[Federal Register Volume 64, Number 189 (Thursday, September 30, 1999)]
[Rules and Regulations]
[Pages 52828-53077]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-20430]



[[Page 52827]]

_______________________________________________________________________

Part II





Environmental Protection Agency





_______________________________________________________________________



40 CFR Part 60, et al.



NESHAPS: Final Standards for Hazardous Air Pollutants for Hazardous 
Waste Combustors; Final Rule

  Federal Register / Vol. 64, No. 189 / Thursday, September 30, 1999 / 
Rules and Regulations  

[[Page 52828]]



ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 60, 63, 260, 261, 264, 265, 266, 270, and 271

[FRL-6413-3]
RIN 2050-AEO1


NESHAPS: Final Standards for Hazardous Air Pollutants for 
Hazardous Waste Combustors

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are promulgating revised standards for hazardous waste 
incinerators, hazardous waste burning cement kilns, and hazardous waste 
burning lightweight aggregate kilns. These standards are being 
promulgated under joint authority of the Clean Air Act (CAA) and 
Resource Conservation and Recovery Act (RCRA). The standards limit 
emissions of chlorinated dioxins and furans, other toxic organic 
compounds, toxic metals, hydrochloric acid, chlorine gas, and 
particulate matter. These standards reflect the performance of Maximum 
Achievable Control Technologies (MACT) as specified by the Clean Air 
Act. These MACT standards also will result in increased protection to 
human health and the environment over existing RCRA standards.

DATES: This final rule is in effect on September 30, 1999. You are 
required to be in compliance with these promulgated standards 3 years 
following the effective date of the final rule (i.e., September 30, 
2002). You are provided with the possibility of a site-specific one 
year extension for the installation of controls to comply with the 
final standards or for waste minimization reductions. The incorporation 
by reference of certain publications listed in the rule was approved by 
the Director of the Federal Register as of September 30, 1999.

ADDRESSES: The official record (i.e., public docket) for this 
rulemaking is identified as Docket Numbers: F-96-RCSP-FFFFF, F-97-CS2A-
FFFFF, F-97-CS3A-FFFFF, F-97-CS4A-FFFFF, F-97-CS5A-FFFFF, F-97-CS6A-
FFFFF, F-98-RCSF-FFFFF, and F-1999-RC2F-FFFFF. The official record is 
located in the RCRA Information Center (RIC), located at Crystal 
Gateway One, 1235 Jefferson Davis Highway, First Floor, Arlington, 
Virginia. The mailing address for the official record is RCRA 
Information Center, Office of Solid Waste (5305W), U.S. Environmental 
Protection Agency Headquarters, 401 M Street, SW, Washington, DC 20460.
    Public comments and supporting materials are available for viewing 
in the RIC. The RIC is open from 9 a.m. to 4 p.m., Monday through 
Friday, excluding federal holidays. To review docket materials, you 
must make an appointment by calling 703-603-9230 or by sending a 
message via e-mail to: RCRA-D[email protected]. You may copy a 
maximum of 100 pages from any regulatory docket at no charge. 
Additional copies cost 15 cent/page. The index for the official record 
and some supporting materials are available electronically. See the 
``Supplementary Information'' section of this Federal Register notice 
for information on accessing the index and these supporting materials.

FOR FURTHER INFORMATION CONTACT: For general information, you can 
contact the RCRA Hotline at 1-800-424-9346 or TDD 1-800-553-7672 
(hearing impaired). In the Washington metropolitan area, call 703-412-
9810 or TDD 703-412-3323. For additional information on the Hazardous 
Waste Combustion MACT rulemaking and to access available electronic 
documents, please go to our Web page: www.epa.gov/hwcmact. Any 
questions or comments on this rule can also be sent to EPA via our Web 
page.
    For more detailed information on technical requirements of this 
rulemaking, you can contact Mr. David Hockey, 703-308-8846, electronic 
mail: Hockey.D[email protected]. For more detailed information on 
permitting associated with this rulemaking, you can contact Ms. 
Patricia Buzzell, 703-308-8632, electronic mail: 
Buzzell.T[email protected]. For more detailed information on 
compliance issues associated with this rulemaking, you can contact Mr. 
Larry Gonzalez, 703-308-8468, electronic mail: 
Gonzalez.L[email protected]. For more detailed information on the 
assessment of potential costs, benefits and other impacts associated 
with this rulemaking, you can contact Mr. Lyn Luben, 703-308-0508, 
electronic mail: Luben.L[email protected]. For more detailed 
information on risk analyses associated with this rulemaking, you can 
contact Mr. David Layland, 703-308-0482, electronic mail: 
Layland.D[email protected].

SUPPLEMENTARY INFORMATION:
    Official Record. The official record is the paper record maintained 
at the address in ADDRESSES above. All comments that were received 
electronically were converted into paper form and placed in the 
official record, which also includes all comments submitted directly in 
writing. Our responses to comments, whether the comments are written or 
electronic, are located in the response to comments document in the 
official record for this rulemaking.
    Supporting Materials Availability on the Internet. The index for 
the official record and the following supporting materials are 
available on the Internet as:
--Technical Support Documents for HWC MACT Standards:
    --Volume I: Description of Source Categories
    --Volume II: HWC Emissions Database
    --Volume III: Selection of MACT Standards and Technologies
    --Volume IV: Compliance with the MACT Standards
    --Volume V: Emission Estimates and Engineering Costs
--Assessment of the Potential Costs, Benefits and Other Impacts of the 
Hazardous Waste Combustion MACT Standards--Final Rule
--Risk Assessment Support to the Development of Technical Standards for 
Emissions from Combustion Units Burning Hazardous Wastes: Background 
Information Document
--Response to Comments for the HWC MACT Standards Document

    To access the information electronically from the World Wide Web 
(WWW), type: www.epa.gov/hwcmact

Outline

Acronyms Used in the Rule

acfm--Actual cubic feet per minute
BIF--Boilers and industrial furnaces
CAA--Clean Air Act
CEMS--Continuous emissions monitors/monitoring system
CFR--Code of Federal Regulations
DOC--Documentation of Compliance
DRE--Destruction and Removal Efficiency
dscf--Dry standard cubic foot
dscm--Dry standard cubic meter
EPA/USEPA--United States Environmental Protection Agency gr--Grains
HSWA--Hazardous and Solid Waste Amendments
kg--Kilogram
MACT--Maximum Achievable Control Technology
mg--Milligrams
Mg--Megagrams (metric tons)
NOC--Notification of Compliance
NESHAP--National Emission Standards for HAPs
ng--Nanograms
NODA--Notice of Data Availability
NPRM--Notice of Proposed Rulemaking
POHC--Principal Organic Hazardous Constituent

[[Page 52829]]

ppmv--Parts per million by volume
ppmw--Parts per million by weight
RCRA--Resource Conservation and Recovery Act
R & D--Research and Development
SSRA--Site specific risk assessment
TEQ--Toxicity equivalence
g--Micrograms

Outline

Part One: Overview and Background for This Rule
    I. What Is the Purpose of This Rule?
    II. In Brief, What Are the Major Features of Today's Rule?
    A. Which Source Categories Are Affected By This Rule?
    B. How Are Area Sources Affected By This Rule?
    C. What Emission Standards Are Established In This Rule?
    D. What Are the Procedures for Complying with This Rule?
    E. What Subsequent Performance Testing Must Be Performed?
    F. What Is the Time Line for Complying with This Rule?
    G. How Does This Rule Coordinate With the Existing RCRA 
Regulatory Program?
    III. What Is the Basis of Today's Rule?
    IV. What Was the Rulemaking Process for Development of This 
Rule?
Part Two: Which Devices Are Subject to Regulation?
    I. Hazardous Waste Incinerators
    II. Hazardous Waste Burning Cement Kilns
    III. Hazardous Waste Burning Lightweight Aggregate Kilns
Part Three: How Were the National Emission Standards for Hazardous 
Air Pollutants (NESHAP) in This Rule Determined?
    I. What Authority Does EPA Have to Develop a NESHAP?
    II. What Are the Procedures and Criteria for Development of 
NESHAPs?
    A. Why Are NESHAPs Needed?
    B. What Is a MACT Floor?
    C. How Are NESHAPs Developed?
    III. How Are Area Sources and Research, Development, and 
Demonstration Sources Treated in this Rule?
    A. Positive Area Source Finding for Hazardous Waste Combustors
    1. How Are Area Sources Treated in this Rule?
    2. What Is an Area Source?
    3. What Is the Basis for Today's Positive Area Source Finding?
    B. How Are Research, Development, and Demonstration (RD&D) 
Sources Treated in this Rule?
    1. Why Does the CAA Give Special Consideration to Research and 
Development (R&D) Sources?
    2. When Did EPA Notice Its Intent to List R&D Facilities?
    3. What Requirements Apply to Research, Development, and 
Demonstration Hazardous Waste Combustor Sources?
    IV. How Is RCRA's Site-Specific Risk Assessment Decision Process 
Impacted by this Rule?
    A. What Is the RCRA Omnibus Authority?
    B. How Will the SSRA Policy Be Applied and Implemented in Light 
of this Mandate?
    1. Is There a Continuing Need for Site-Specific Risk 
Assessments?
    2. How Will the SSRA Policy Be Implemented?
    C. What Is the Difference Between the RCRA SSRA Policy and the 
CAA Residual Risk Requirement?
Part Four: What Is The Rationale for Today's Final Standards?
    I. Emissions Data and Information Data Base
    A. How Did We Develop the Data Base for this Rule?
    B. How Are Data Quality and Data Handling Issues Addressed?
    1. How Are Data from Sources No Longer Burning Hazardous Waste 
Handled?
    2. How Are Nondetect Data Handled?
    3. How Are Normal Versus Worst-Case Emissions Data Handled?
    4. What Approach Was Used to Fill In Missing or Unavailable 
Data?
    II. How Did We Select the Pollutants Regulated by This Rule?
    A. Which Toxic Metals Are Regulated by This Rule?
    1. Semivolatile and Low Volatile Metals
    2. How Are the Five Other Metal Hazardous Air Pollutants 
Regulated?
    B. How Are Toxic Organic Compounds Regulated By This Rule?
    1. Dioxins/Furans
    2. Carbon Monoxide and Hydrocarbons
    3. Destruction and Removal Efficiency
    C. How Are Hydrochloric Acid and Chlorine Gas Regulated By This 
Rule?
    III. How Are the Standards Formatted In This Rule?
    A. What Are the Units of the Standards?
    B. Why Are the Standards Corrected for Oxygen and Temperature?
    C. How Does the Rule Treat Significant Figures and Rounding?
    IV. How Are Nondioxin/Furan Organic Hazardous Air Pollutants 
Controlled?
    A. What Is the Rationale for DRE as a MACT Standard?
    1. MACT DRE Standard
    2. How Can Previous Successful Demonstrations of DRE Be Used To 
Demonstrate Compliance?
    3. DRE for Sources that Feed Waste at Locations Other Than the 
Flame Zone
    4. Sources that Feed Dioxin Wastes
    B. What Is the Rationale for Carbon Monoxide or Hydrocarbon 
Standards as Surrogate Control of Organic Hazardous Air Pollutants?
    V. What Methodology Is Used to Identify MACT Floors?
    A. What Is the CAA Statutory Requirement to Identify MACT 
Floors?
    B. What Is the Final Rule Floor Methodology?
    1. What Is the General Approach Used in this Final Rule?
    2. What MACT Floor Approach Is Used for Each Standard?
    C. What Other Floor Methodologies Were Considered?
    1. April 19, 1996 Proposal
    2. May 1997 NODA.
    D. How Is Emissions Variability Accounted for in Development of 
Standards?
    1. How Is Within-Test Condition Emissions Variability Addressed?
    2. How Is Waste Imprecision in the Stack Test Method Addressed?
    3. How Is Source-to-Source Emissions Variability Addressed?
    VI. What Are the Standards for Existing and New Incinerators?
    A. To Which Incinerators Do Today's Standards Apply?
    B. What Subcategorization Options Did We Evaluate?
    C. What Are the Standards for New and Existing Incinerators?
    1. What Are the Standards for Incinerators?
    2. What Are the Standards for Dioxins and Furans?
    3. What Are the Standards for Mercury?
    4. What Are the Standards for Particulate Matter?
    5. What Are the Standards for Semivolatile Metals?
    6. What Are the Standards for Low Volatile Metals?
    7. What Are the Standards for Hydrochloric Acid and Chlorine 
Gas?
    8. What Are the Standards for Carbon Monoxide?
    9. What Are the Standards for Hydrocarbon?
    10. What Are the Standards for Destruction and Removal 
Efficiency?
    VII. What Are the Standards for Hazardous Waste Burning Cement 
Kilns?
    A. To Which Cement Kilns Do Today's Standards Apply?
    B. How Did EPA Initially Classify Cement Kilns?
    1. What Is the Basis for a Separate Class Based on Hazardous 
Waste Burning?
    2. What Is the Basis for Differences in Standards for Hazardous 
Waste and Nonhazardous Waste Burning Cement Kilns?
    C. What Further Subcategorization Considerations Are Made?
    D. What Are The Standards for Existing and New Cement Kilns?
    1. What Are the Standards for Cement Kilns?
    2. What Are the Dioxin and Furan Standards?
    3. What Are the Mercury Standards?
    4. What Are the Particulate Matter Standards?
    5. What Are the Semivolatile Metals Standards?
    6. What Are the Low Volatile Metals Standards?
    7. What Are the Hydrochloric Acid and Chlorine Gas Standards?
    8. What Are the Hydrocarbon and Carbon Monoxide Standards for 
Kilns Without By-Pass Sampling Systems?
    9. What Are the Carbon Monoxide and Hydrocarbon Standards for 
Kilns With By-Pass Sampling Systems?
    10. What Are the Destruction and Removal Efficiency Standards?
    VIII. What Are the Standards for Existing and New Hazardous 
Waste Burning Lightweight Aggregate Kilns?
    A. To Which Lightweight Aggregate Kilns Do Today's Standards 
Apply?
    B. What Are the Standards for New and Existing Hazardous Waste 
Burning Lightweight Aggregate Kilns?
    1. What Are the Standards for Lightweight Aggregate Kilns?

[[Page 52830]]

    2. What Are the Dioxin and Furan Standards?
    3. What Are the Mercury Standards?
    4. What Are the Particulate Matter Standards?
    5. What Are the Semivolatile Metals Standards?
    6. What Are the Low Volatile Metals Standards?
    7. What Are the Hydrochloric Acid and Chlorine Gas Standards?
    8. What Are the Hydrocarbon and Carbon Monoxide Standards?
    9. What Are the Standards for Destruction and Removal 
Efficiency?
Part Five: Implementation
    I. How Do I Demonstrate Compliance with Today's Requirements?
    A. What Sources Are Subject to Today's Rules?
    1. What Is an Existing Source?
    2. What Is a New Source?
    B. How Do I Cease Being Subject to Today's Rule?
    C. What Requirements Apply If I Temporarily Cease Burning 
Hazardous Waste?
    1. What Must I Do to Comply with Alternative Compliance 
Requirements?
    2. What Requirements Apply If I Do Not Use Alternative 
Compliance Requirements?
    D. What Are the Requirements for Startup, Shutdown and 
Malfunction Plans?
    E. What Are the Requirements for Automatic Waste Feed Cutoffs?
    F. What Are the Requirements of the Excess Exceedance Report?
    G. What Are the Requirements for Emergency Safety Vent Openings?
    H. What Are the Requirements for Combustion System Leaks?
    I. What Are the Requirements for an Operation and Maintenance 
Plan?
    II. What Are the Compliance Dates for this Rule?
    A. How Are Compliance Dates Determined?
    B. What Is the Compliance Date for Sources Affected on April 19, 
1996?
    C. What Is the Compliance Date for Sources That Become Affected 
After April 19, 1996?
    III. What Are the Requirements for the Notification of Intent to 
Comply?
    IV. What Are the Requirements for Documentation of Compliance?
    A. What Is the Purpose of the Documentation of Compliance?
    B. What Is the Rationale for the DOC?
    C. What Must Be in the DOC?
    V. What Are the Requirements for MACT Performance Testing?
    A. What Are the Compliance Testing Requirements?
    1. What Are the Testing and Notification of Compliance 
Schedules?
    2. What Are the Procedures for Review and Approval of Test Plans 
and Requirements for Notification of Testing?
    3. What Is the Provision for Time Extensions for Subsequent 
Performance Tests?
    4. What Are the Provisions for Waiving Operating Parameter 
Limits During Subsequent Performance Tests?
    B. What Is the Purpose of Comprehensive Performance Testing?
    1. What Is the Rationale for the Five Year Testing Frequency?
    2. What Operations Are Allowed During a Comprehensive 
Performance Test?
    3. What Is the Consequence of Failing a Comprehensive 
Performance Test?
    C. What Is the Rationale for Confirmatory Performance Testing?
    1. Do the Comprehensive Testing Requirements Apply to 
Confirmatory Testing?
    2. What Is the Testing Frequency for Confirmatory Testing?
    3. What Operations Are Allowed During Confirmatory Performance 
Testing?
    4. What Are the Consequences of Failing a Confirmatory 
Performance Test?
    D. What Is the Relationship Between the Risk Burn and 
Comprehensive Performance Test?
    1. Is Coordinated Testing Allowed?
    2. What Is Required for Risk Burn Testing?
    E. What Is a Change in Design, Operation, and Maintenance?
    F. What are the Data In Lieu Allowances?
    VI. What Is the Notification of Compliance?
    A. What Are the Requirements for the Notification of Compliance?
    B. What Is Required in the NOC?
    C. What Are the Consequences of Not Submitting a NOC?
    D. What Are the Consequences of an Incomplete Notification of 
Compliance?
    E. Is There a Finding of Compliance?
    VII. What Are the Monitoring Requirements?
    A. What Is the Compliance Monitoring Hierarchy?
    B. How Are Comprehensive Performance Test Data Used to Establish 
Operating Limits?
    1. What Are the Definitions of Terms Related to Monitoring and 
Averaging Periods?
    2. What Is the Rationale for the Averaging Periods for the 
Operating Parameter Limits?
    3. How Are Performance Test Data Averaged to Calculate Operating 
Parameter Limits?
    4. How Are the Various Types of Operating Parameters Monitored 
or Established?
    5. How Are Rolling Averages Calculated Initially, Upon 
Intermittent Operations, and When the Hazardous Waste Feed Is Cut 
Off?
    6. How Are Nondetect Performance Test Feedstream Data Handled?
    C. Which Continuous Emissions Monitoring Systems Are Required in 
the Rule?
    1. What Are the Requirements and Deferred Actions for 
Particulate Matter CEMS?
    2. What Are the Test Methods, Specifications, and Procedures?
    3. What Is the Status of Total Mercury CEMS?
    4. What Is the Status of the Proposed Performance Specifications 
for Multimetal, Hydrochloric Acid, and Chlorine Gas CEMS?
    5. How Have We Addressed Other Issues: Continuous Samplers as 
CEMS, Averaging Periods for CEMS, and Incentives for Using CEMS?
    D. What Are the Compliance Monitoring Requirements?
    1. What Are the Operating Parameter Limits for Dioxin/Furan?
    2. What Are the Operating Parameter Limits for Mercury?
    3. What Are the Operating Parameter Limits for Semivolatile and 
Low Volatile Metals?
    4. What Are the Monitoring Requirements for Carbon Monoxide and 
Hydrocarbon?
    5. What Are the Operating Parameter Limits for Hydrochloric 
Acid/Chlorine Gas?
    6. What Are the Operating Parameter Limits for Particulate 
Matter?
    7. What Are the Operating Parameter Limits for Destruction and 
Removal Efficiency?
    VIII. Which Methods Should Be Used for Manual Stack Tests and 
Feedstream Sampling and Analysis?
    A. Manual Stack Sampling Test Methods
    B. Sampling and Analysis of Feedstreams
    IX. What Are the Reporting and Recordkeeping Requirements?
    A. What Are the Reporting Requirements?
    B. What Are the Recordkeeping Requirements?
    C. How Can You Receive Approval to Use Data Compression 
Techniques?
    X. What Special Provisions Are Included in Today's Rule?
    A. What Are the Alternative Standards for Cement Kilns and 
Lightweight Aggregate Kilns?
    1. What Are the Alternative Standards When Raw Materials Cause 
an Exceedance of an Emission Standard?
    2. What Special Provisions Exist for an Alternative Mercury 
Standard for Kilns?
    B. Under What Conditions Can the Performance Testing 
Requirements Be Waived?
    1. How Is This Waiver Implemented?
    2. How Are Detection Limits Handled Under This Provision?
    C. What Other Waiver Was Proposed, But Not Adopted?
    D. What Equivalency Determinations Were Considered, But Not 
Adopted?
    E. What are the Special Compliance Provisions and Performance 
Testing Requirements for Cement Kilns with In-line Raw Mills and 
Dual Stacks?
    F. Is Emission Averaging Allowable for Cement Kilns with Dual 
Stacks and In-line Raw Mills?
    1. What Are the Emission Averaging Provisions for Cement Kilns 
with In-line Raw Mills?
    2. What Emission Averaging Is Allowed for Preheater or 
Preheater-Precalciner Kilns with Dual Stacks?
    G. What Are the Special Regulatory Provisions for Cement Kilns 
and Lightweight Aggregate Kilns that Feed Hazardous Waste at a 
Location Other Than the End Where Products Are Normally Discharged 
and Where Fuels Are Normally Fired?
    H. What is the Alternative Particulate Matter Standard for 
Incinerators?

[[Page 52831]]

    1. Why is this Alternative Particulate Matter Standard 
Appropriate under MACT?
    2. How Do I Demonstrate Eligibility for the Alternative 
Standard?
    3. What is the Process for the Alternative Standard Petition?
    XI. What Are the Permitting Requirements for Sources Subject to 
this Rule?
    A. What Is the Approach to Permitting in this Rule?
    1. In General What Was Proposed and What Was Commenters' 
Reaction?
    2. What Permitting Approach Is Adopted in Today's Rule?
    3. What Considerations Were Made for Ease of Implementation?
    B. What Is the Applicability of the Title V and RCRA Permitting 
Requirements?
    1. How Are the Title V Permitting Requirements Applicable?
    2. What Is the Relationship Between the Notification of 
Compliance and the Title V Permit?
    3. Which RCRA Permitting Requirements Are Applicable?
    4. What Is the Relationship of Permit Revisions to RCRA 
Combustion Permitting Procedures?
    5. What is the Relationship to the RCRA Preapplication Meeting 
Requirements?
    C. Is Title V Permitting Applicable to Area Sources?
    D. How will Sources Transfer from RCRA to MACT Compliance and 
Title V Permitting?
    1. In General, How Will this Work?
    2. How Will I Make the Transition to CAA Permits?
    3. When Should RCRA Permits Be Modified?
    4. How Should RCRA Permits Be Modified?
    5. How Should Sources in the Process of Obtaining RCRA Permits 
be Switched Over to Title V?
    E. What is Meant by Certain Definitions?
    1. Prior Approval
    2. 50 Percent Benchmark
    3. Facility Definition
    4. No New Eligibility for Interim Status
    5. What Constitutes Construction Requiring Approval?
    XII. State Authorization
    A. What is the Authority for Today's Rule?
    B. How is the Program Delegated Under the Clean Air Act?
    C. How are States Authorized Under RCRA?
Part Six: Miscellaneous Provisions and Issues
    I. Does the Waiver of the Particulate Matter Standard or the 
Destruction and Removal Efficiency Standard Under the Low Risk Waste 
Exemption of the BIF Rule Apply?
    II. What is the Status of the ``Low Risk Waste'' Exemption?
    III. What Concerns Have Been Considered for Shakedown?
    IV. What Are the Management Requirements Prior to Burning?
    V. Are There Any Conforming Changes to Subpart X?
    VI. What Are the Requirements for Bevill Residues?
    A. Dioxin Testing of Bevill Residues
    B. Applicability of Part 266 Appendix VIII Products of 
Incomplete Combustion List
    VII. Have There Been Any Changes in Reporting Requirements for 
Secondary Lead Smelters?
    VIII. What Are the Operator Training and Certification 
Requirements?
    IX. Why Did the Agency Redesignate Existing Regulations 
Pertaining to the Notification of Intent to Comply and Extension of 
the Compliance Date?
Part Seven: National Assessment of Exposures and Risks
    I. What Changes Were Made to the Risk Methodology?
    A. How Were Facilities Selected for Analysis?
    B. How Were Facility Emissions Estimated?
    C. What Receptor Populations Were Evaluated?
    D. How Were Exposure Factors Determined?
    E. How Were Risks from Mercury Evaluated?
    F. How Were Risks from Dioxins Evaluated?
    G. How Were Risks from Lead Evaluated?
    H. What Analytical Framework Was Used to Assess Human Exposures 
and Risk?
    I. What Analytical Framework Was Used to Assess Ecological Risk?
    II. How Were Human Health Risks Characterized?
    A. What Potential Health Hazards Were Evaluated?
    1. Dioxins
    2. Mercury
    3. Lead
    4. Other Metals
    5. Hydrogen Chloride
    6. Chlorine
    B. What are the Health Risks to Individuals Residing Near HWC 
Facilities?
    1. Dioxins
    2. Mercury
    3. Lead
    4. Other Metals
    5. Inhalation Carcinogens
    6. Other Inhalation Exposures
    C. What are the Potential Health Risks to Highly Exposed 
Individuals?
    1. Dioxins
    2. Metals
    3. Mercury
    D. What is the Incidence of Adverse Health Effects in the 
Population?
    1. Cancer Risk in the General Population
    2. Cancer Risk in the Local Population
    3. Risks from Lead Emissions
    4. Risks from Emissions of Particulate Matter
    III. What is the Potential for Adverse Ecological Effects?
    A. Dioxins
    B. Mercury
Part Eight: Analytical and Regulatory Requirements
    I. Executive Order 12866: Regulatory Planning and Review (58 FR 
51735)
    II. What Activities Have Led to Today's Rule?
    A. What Analyses Were Completed for the Proposal?
    1. Costs
    2. Benefits
    3. Other Regulatory Issues
    4. Small Entity Impacts
    B. What Major Comments Were Received on the Proposal RIA?
    1. Public Comments
    2. Peer Review
    III. Why is Today's Rule Needed?
    IV. What Were the Regulatory Options?
    V. What Are the Potential Costs and Benefits of Today's Rule?
    A. Introduction
    B. Combustion Market Overview
    C. Baseline Specification
    D. Analytical Methodology and Findings--Engineering Compliance 
Cost Analysis
    E. Analytical Methodology and Findings--Social Cost Analysis
    F. Analytical Methodology and Findings--Economic Impact Analysis
    1. Market Exit Estimates
    2. Quantity of Waste Reallocated
    3. Employment Impacts
    4. Combustion Price Increases
    5. Industry Profits
    6. National-Level Joint Economic Impacts
    G. Analytical Methodology and Findings--Benefits Assessment
    1. Human Health and Ecological Benefits
    2. Waste Minimization Benefits
    VI. What Considerations Were Given to Issues Like Equity and 
Children's Health?
    A. Executive Order 12898, ``Federal Actions to Address 
Environmental Justice in Minority Populations and Low-Income 
Populations'' (February 11, 1994)
    B. Executive Order 13045: Protection of Children from 
Environmental Health Risks and Safety Risks (62 FR 19885, April 23, 
1997)
    C. Unfunded Mandates Reform Act of 1995 (URMA) (Pub. Law 104-4)
    VII. Is Today's Rule Cost Effective?
    VIII. How Do the Costs of Today's Rule Compare to the Benefits?
    IX. What Consideration Was Given to Small Businesses?
    A. Regulatory Flexibility Act (RFA) as amended by the Small 
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 
U.S.C. 601 et seq.
    B. Analytical Methodology
    C. Results--Direct Impacts
    D. Results--Indirect Impacts
    E. Key Assumptions and Limitations
    X. Were Derived Air Quality and Non-Air Impacts Considered?
    XI. The Congressional Review Act (5 U.S.C. 801 et seq., as added 
by the Small Business Regulatory Enforcement Fairness Act of 1996)
    XII. Paperwork Reduction Act (PRA), 5 U.S.C. 3501-3520
    XIII. National Technology Transfer and Advancement Act of 1995 
(Pub L. 104-113, section 12(d)) (15 U.S.C. 272 note)
    XIV. Executive Order 13084: Consultation and Coordination With 
Indian Tribal Governments (63 FR 27655)
Part Nine: Technical Amendments to Previous Regulations
    I. Changes to the June 19, 1998 ``Fast-track'' Rule
    A. Permit Streamlining Section
    B. Comparable Fuels Section

[[Page 52832]]

Part One: Overview and Background for This Rule

I. What Is the Purpose of This Rule?

    In this final rule, we adopt hallmark standards to more rigorously 
control toxic emissions from burning hazardous waste in incinerators, 
cement kilns, and lightweight aggregate kilns. These emission standards 
and continuation of our RCRA risk policy create a national cap for 
emissions that assures that combustion of hazardous waste in these 
devices is properly controlled.
    The standards themselves implement section 112 of the Clean Air Act 
(CAA) and apply to the three major categories of hazardous waste 
burners--incinerators, cement kilns, and lightweight aggregate kilns. 
For purposes of today's rule, we refer to these three categories 
collectively as hazardous waste combustors. Hazardous waste combustors 
burn about 80% of the hazardous waste combusted annually within the 
United States. As a result, we project that today's standards will 
achieve highly significant reductions in the amount of hazardous air 
pollutants being emitted each year by hazardous waste combustors. For 
example, we estimate that 70 percent of the annual dioxin and furan 
emissions from hazardous waste combustors will be eliminated. Mercury 
emissions already controlled to some degree under existing regulations 
will be further reduced by about 55 percent.
    Section 112 of the CAA requires emissions standards for hazardous 
air pollutants to be based on the performance of the Maximum Achievable 
Control Technology (MACT). The emission standards in this final rule 
are commonly referred to as MACT standards because we use the MACT 
concept to determine the levels of emission control under section 
112(d) of the CAA.1 At the same time, these emissions 
standards satisfy our obligation under the main statute regulating 
hazardous waste management, the Resource Conservation Recovery Act 
(RCRA), to ensure that hazardous waste combustion is conducted in a 
manner adequately protective of human health and the environment. Our 
use of both authorities as the legal basis for today's rule and details 
of the MACT standard-setting process are explained more fully in later 
sections of this preamble. Most significantly, by using both 
authorities in a harmonized fashion, we consolidate regulatory control 
of hazardous waste combustion into a single set of regulations, thereby 
eliminating the potential for conflicting or duplicative federal 
requirements.
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    \1\ The MACT standards reflect the ``maximum degree of reduction 
in emissions of * * * hazardous air pollutants'' that the 
Administrator determines is achievable, taking into account the cost 
of achieving such emission reduction and any nonair quality health 
and environmental impacts and energy requirements. Section 
112(d)(2).
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    Today's rule also has other important features in terms of our 
legal obligations and public commitments. First, promulgation of these 
standards fulfills our legal obligations under the CAA to control 
emissions of hazardous air pollutants from hazardous-waste burning 
incinerators and Portland cement kilns.2 Second, today's 
rule fulfills our 1993 and 1994 public commitments to upgrade emission 
standards for hazardous waste combustors. These commitments are the 
centerpiece of our Hazardous Waste Minimization and Combustion 
Strategy.3 Finally, today's rulemaking satisfies key terms 
of a litigation settlement agreement entered into in 1993 with a number 
of groups that had challenged our previous rule addressing emissions 
from hazardous waste boilers and industrial furnaces.4
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    \2\ In a 1992 Federal Register notice, we published the inital 
list of categories of major and area sources of hazardous air 
pollutants including hazardous waste incinerators and Portland 
cement plants. See 57 FR 31576 (July 16, 1992). Today's rule meets 
our obligation to issue MACT standards for hazardous waste 
incinerators. Today's rule also partially meets our obligation to 
issue MACT standards for Portland cement plants. To complete the 
obligation, we have finalized, in a separate rulemaking, MACT 
standards for the portland cement industry source category. Those 
standards apply to all cement kilns except those kilns that burn 
hazardous waste. See 64 FR 31898 (June 14, 1999). Those standards 
also apply to other HAP emitting sources at a cement plant (such as 
clinker coolers, raw mills, finish mills, and materials handling 
operations) regardless of whether the plant has hazardous waste 
burning cement kilns.
    \3\ EPA Document Number 530-R-94-044, Office of Solid Waste and 
Emergency Response, November 1994.
    \4\ ``Burning of Hazardous Waste in Boilers and Industrial 
Furnaces'' (56 FR 7134, February 21, 1991). These groups include the 
Natural Resources Defense Council, Sierra Club, Environmental 
Technology Council, National Solid Waste Management Association, and 
a number of local citizens' groups.
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II. In Brief, What Are the Major Features of Today's Rule?

    The major features of today's final rule are summarized below.
A. Which Source Categories Are Affected by This Rule?
    This rule establishes MACT standards for three source categories, 
namely: Hazardous waste burning incinerators, hazardous waste burning 
cement kilns, and hazardous waste burning lightweight aggregate kilns. 
As mentioned earlier, we refer to these three source categories 
collectively as hazardous waste combustors.
B. How Are Area Sources Affected by This Rule?
    This rule establishes that MACT standards apply to both major 
sources--sources that emit or have the potential to emit 10 tons or 
greater per year of any single hazardous air pollutant or 25 tons per 
year or greater of hazardous air pollutants in the aggregate--and area 
sources, all others. Area sources may be regulated under MACT standards 
if we find that the category of area sources ``presents a threat of 
adverse effects to human health or the environment * * * warranting 
regulation (under the MACT standards).'' We choose to regulate area 
sources in today's rule and, as a result, all hazardous waste burning 
incinerators, cement kilns, and lightweight aggregate kilns will be 
regulated under standards reflecting MACT.
C. What Emission Standards Are Established in This Rule?
    This rule establishes emission standards for: Chlorinated dioxins 
and furans; mercury; particulate matter (as a surrogate for antimony, 
cobalt, manganese, nickel, and selenium); semivolatile metals (lead and 
cadmium); low volatile metals (arsenic, beryllium, and chromium); 
hydrogen chloride and chlorine gas (combined). This rule also 
establishes standards for carbon monoxide, hydrocarbons, and 
destruction and removal efficiency as surrogates in lieu of individual 
standards for nondioxin/furan organic hazardous air pollutants.
D. What Are the Procedures for Complying With This Rule?
    This rule establishes standards that apply at all times (including 
during startup, shutdown, or malfunction), except if hazardous waste is 
not being burned or is not in the combustion chamber. When not burning 
hazardous waste (and when hazardous waste does not remain in the 
combustion chamber), you may either follow the hazardous waste burning 
standards in this rule or emission standards we promulgate, if any, for 
other relevant nonhazardous waste source categories.
    Initial compliance is documented by stack performance testing. To 
document continued compliance with the carbon monoxide or hydrocarbon 
standards, you must use continuous emissions monitoring systems. For 
the remaining standards, you must document continued compliance by 
monitoring limits on specified operating parameters. These operating 
parameter

[[Page 52833]]

limits 5 are calculated based on performance test conditions 
using specified procedures intended to ensure that the operating 
conditions (and by correlation the actual emissions) do not exceed 
performance test levels at any time. You must also install an automatic 
waste feed cutoff system that immediately stops the flow of hazardous 
waste feed to the combustor if a continuous emissions monitoring system 
records a value exceeding the standard or if an operating parameter 
limit is exceeded (considering the averaging period for the standard or 
operating parameter). The standards and operating parameter limits 
apply when hazardous waste is being fed or remains in the combustion 
chamber irrespective of whether you institute the corrective measures 
prescribed in the startup, shutdown, and malfunction plan.
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    \5\ The term ``operating parameter limit'' and ``operating 
limit'' have the same meaning and are used interchangeably in the 
preamble and rule language.
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E. What Subsequent Performance Testing Must Be Performed?
    You must conduct comprehensive performance testing every five 
years. This testing regime is referred to as ``subsequent performance 
testing.'' You must revise the operating parameter limits as necessary 
based on the levels achieved during the subsequent performance test. In 
addition, you must conduct confirmatory performance testing of dioxins/
furans emissions under normal operating conditions midway between 
subsequent performance tests.
F. What Is the Time Line for Complying With This Rule?
    The compliance date of the standards promulgated in today's rule is 
three years after the date of publication of the rule in the Federal 
Register, or September 30, 2002 (See CAA section 112(i)(3)(A) 
indicating that the Environmental Protection Agency (EPA) may establish 
a compliance date no later than three years from the date of 
promulgation.) A one-year extension of the compliance date may be 
requested if you cannot complete system retrofits by the compliance 
date despite a good faith effort to do so.6 CAA section 
112(i)(3)(B).
Continuous emissions monitoring systems and other continuous monitoring 
systems for the specified operating parameters must be fully 
operational by the compliance date. You must demonstrate compliance by 
conducting a performance test no later than 6 months after the 
compliance date (i.e., three and one-half years from the date of 
publication of today's rule in the Federal Register).
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    \6\ In June 1998, we promulgated a rule to allow hazardous waste 
combustors also to request a one-year extension to the MACT 
compliance date in cases where additional time will be needed to 
install pollution prevention and waste minimization measures to 
significantly reduce the amount or toxicity of hazardous waste 
entering combustion feedstreams. See 63 FR at 43501 (June 19, 1998). 
This provision is recodified in today's rule as 40 CFR 63.1213.
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    To ensure timely compliance with the standards, by the compliance 
date you must place in the operating record a Documentation of 
Compliance identifying limits on the specified operating parameters you 
believe are necessary and sufficient to comply with the emission 
standards. These operating parameter limits (and the carbon monoxide or 
hydrocarbon standards monitored with continuous monitoring systems) are 
enforceable until you submit to the Administrator a Notification of 
Compliance within 90 days of completion of the performance test.
    The Notification of Compliance must document: (1) Compliance with 
the emission standards during the performance test; (2) the revised 
operating parameter limits calculated from the performance test; and 
(3) conformance of the carbon monoxide or hydrocarbon continuous 
emissions monitoring systems and the other continuous monitoring 
systems with performance specifications. You must comply with the 
revised operating parameter limits upon submittal of the Notification 
of Compliance.
G. How Does This Rule Coordinate With the Existing RCRA Regulatory 
Program?
    You must have a RCRA permit for stack air emissions (or RCRA 
interim status) until you demonstrate compliance with the MACT 
standards. You do so by conducting a comprehensive performance test and 
submitting a Notification of Compliance to the Administrator, as 
explained above.7 Hazardous waste combustors with RCRA 
permits remain subject to RCRA stack air emission permit conditions 
until the RCRA permit is modified to delete those conditions. (As 
discussed later in more detail, we recommend requesting modification of 
the RCRA permit at the time you submit the Notification of Compliance.) 
Only those provisions of the RCRA permit that are less stringent than 
the MACT requirements specified in the Notification of Compliance will 
be approved for deletion.8 Hazardous waste combustors still 
in interim status without a full RCRA permit are no longer subject to 
the RCRA stack air emissions standards for hazardous waste combustors 
in Subpart O of Part 265 and subpart H of part 266 once compliance with 
the MACT standards has been demonstrated and a Notification of 
Compliance has been submitted to the Administrator.
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    \7\ Hazardous waste combustors, of course, also continue to be 
subject to applicable RCRA requirements for all other aspects of 
their hazardous waste management activities that are separate from 
the requirements being deferred to the CAA by this rule.
    \8\ RCRA permit requirements that may be less stringent than 
applicable MACT standards are nonetheless enforceable until the RCRA 
permit is modified.
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    You must satisfy both sets of requirements during the relatively 
short period when both RCRA and MACT stack air emissions standards and 
associated requirements in the RCRA permit or in RCRA interim status 
regulations are effective.
    You also may have existing site-specific permit conditions. On a 
case-by-case basis during RCRA permit issuance or renewal, we determine 
whether further regulatory control of emissions is needed to protect 
human health and the environment, notwithstanding compliance with 
existing regulatory standards. Additional conditions may be included in 
the permit in addition to those derived from the RCRA emission 
standards as necessary to ensure that facility operations are 
protective of human health and the environment. Any of these risk-based 
permit provisions more stringent than today's MACT standards (or that 
address other emission hazards) will remain in the RCRA permit.
    After the MACT compliance date, hazardous waste combustors must 
continue to comply with the RCRA permit issuance process to address 
nonMACT provisions (e.g., general facility standards) and potentially 
conduct a risk review under Sec. 270.32(b)(2) to determine if 
additional requirements pertaining to stack or other emissions are 
warranted to ensure protection of human health and the environment.

III. What Is the Basis of Today's Rule?

    As stated previously, this rule issues final National Emissions 
Standards for Hazardous Air Pollutants (NESHAPS) under authority of 
section 112 of the Clean Air Act for three source categories of 
combustors: Hazardous waste burning incinerators, hazardous waste 
burning cement kilns, and hazardous waste burning lightweight aggregate 
kilns. The main purposes of the CAA are to protect and enhance the 
quality of our Nation's

[[Page 52834]]

air resources, and to promote the public health and welfare and the 
productive capacity of the population. CAA section 101(b)(1). To this 
end, sections 112(a) and (d) of the CAA direct EPA to set standards for 
stationary sources emitting (or having the potential to emit) ten tons 
or greater of any one hazardous air pollutant or 25 tons or greater of 
total hazardous air pollutants annually. Such sources are referred to 
as ``major sources.''
    Today's rule establishes MACT emission standards for the following 
hazardous air pollutants emitted by hazardous waste burning 
incinerators, hazardous waste burning cement kilns, and hazardous waste 
burning lightweight aggregate kilns: Chlorinated dioxins and furans, 
mercury, two semivolatile metals (lead and cadmium), three low 
volatility metals (arsenic, beryllium, and chromium), and hydrochloric 
acid/chlorine gas. This rule also establishes MACT control for the 
other hazardous air pollutants identified in CAA section 112(b)(1) 
through the adoption of standards using surrogates. For example, we 
adopt a standard for particulate matter as a surrogate to control five 
metals that do not have specific emission standards established in 
today's rule. These five metals are antimony, cobalt, manganese, 
nickel, and selenium. Also, we adopt standards for carbon monoxide, 
hydrocarbons, and destruction and removal efficiency to control the 
other organic hazardous air pollutants listed in section 112(b)(1) that 
do not have specific emission standards established in this rule.
    Today's standards meet our commitment under the Hazardous Waste 
Minimization and Combustion Strategy, first announced in May 1993, to 
upgrade the emission standards for hazardous waste burning facilities. 
EPA's Strategy has eight goals: (1) Ensure public outreach and EPA-
State coordination; (2) pursue aggressive use of waste minimization 
measures; (3) continue to ensure that combustion and alternative and 
innovative technologies are safe and effective; (4) develop and impose 
more rigorous controls on combustion facilities; (5) continue 
aggressive compliance and enforcement efforts; (6) enhance public 
involvement opportunities in the permitting process for combustion 
facilities; (7) give higher priority to permitting those facilities 
where a final permit decision would result in the greatest 
environmental benefit or the greatest reduction in risk; and (8) 
advance scientific understanding on combustion issues and risk 
assessment and ensure that permits are issued in a manner that provides 
proper protection of human health and the environment.
    We have made significant progress in implementing the Strategy. 
Today's rule meets the Strategy goal of developing and implementing 
rigorous state-of-the-art safety controls on hazardous waste combustors 
by using the best available technologies and the most current 
science.9 We also developed a software tool (i.e., the Waste 
Minimization Prioritization Tool) that allows users to access relative 
persistent, bioaccumulative and toxic hazard scores for any of 2,900 
chemicals that may be present in RCRA waste streams. We also committed 
to the reduction of the generation of the most persistent, 
bioaccumulative and toxic chemicals by 50 percent by 2005. To 
facilitate this reduction we are developing a list of the persistent, 
bioaccumulative and toxic chemicals of greatest concern and a plan for 
working with the regulated community to reduce these chemicals. In 
addition, we promulgated new requirements to enhance public involvement 
in the permitting process 10 and performed risk evaluations 
during the permitting process for high priority facilities. We also 
made allowances for one-year extensions to the MACT compliance period 
as incentives designed to promote the installation of cost-effective 
pollution prevention technologies to replace or supplement emission 
control technologies for meeting MACT standards.
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    \9\ The three source categories covered by today's final rule 
burn more than 80 percent of the total amount of hazardous waste 
being combusted each year. The remaining 15-20 percent is burned in 
industrial boilers and other types of industrial furnaces, which 
will be addressed in a future NESHAPS rulemaking for hazardous waste 
burning sources.
    \10\ See 60 FR 63417 (December 11, 1995).
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    Finally, with regard to the regulatory framework that will result 
from today's rule, we are eliminating the existing RCRA stack emissions 
national standards for hazardous waste incinerators, cement kilns, and 
lightweight aggregate kilns. That is, after submittal of the 
Notification of Compliance established by today's rule (and, where 
applicable, RCRA permit modifications at individual facilities), RCRA 
national stack emission standards will no longer apply to these 
hazardous waste combustors. We originally issued air emission standards 
under the authority of section 3004(a) of RCRA, which calls for EPA to 
promulgate standards ``as may be necessary to protect human health and 
the environment.'' In light of today's new MACT standards, we have 
determined that RCRA emissions standards for these sources would only 
be duplicative and so are no longer necessary to protect human health 
and the environment. Under the authority of section 3004(a), it is 
appropriate to eliminate such duplicative standards.
    Emission standards for hazardous waste burning incinerators and 
other sources burning hazardous wastes as fuel must be protective of 
human health and the environment under RCRA. We conducted a 
multipathway risk assessment to assess the ecological and human health 
risks that are projected to occur under the MACT standards. We have 
concluded that the MACT standards are generally protective of human 
health and the environment and that separate RCRA emission standards 
are not needed. Please see a full discussion of the national assessment 
of exposures and risk in Part VIII of this preamble.
    Additionally, RCRA section 1006(b) directs EPA to integrate the 
provisions of RCRA for purposes of administration and enforcement and 
to avoid duplication, to the maximum extent practicable, with the 
appropriate provisions of the Clean Air Act and other federal statutes. 
This integration must be done in a way that is consistent with the 
goals and policies of these statutes. Therefore, section 1006(b) 
provides further authority for EPA to eliminate the existing RCRA stack 
emissions standards to avoid duplication with the new MACT standards. 
Nevertheless, under the authority of RCRA's ``omnibus'' clause (section 
3005(c)(3); see 40 CFR 270.32(b)(2)), RCRA permit writers may still 
impose additional terms and conditions on a site-specific basis as may 
be necessary to protect human health and the environment.

IV. What Was the Rulemaking Process for Development of This Rule?

    We proposed MACT standards for hazardous waste burning 
incinerators, hazardous waste burning cement kilns, and hazardous waste 
burning lightweight aggregate kilns on April 19, 1996. (61 FR 17358) In 
addition, we published five notices of data availability (NODAs):
    1. August 23, 1996 (61 FR 43501), inviting comment on information 
pertaining to a peer review of three aspects of the proposed rule and 
information pertaining to the since-promulgated ``Comparable Fuels'' 
rule (see 63 FR 43501 (June 19, 1998));
    2. January 7, 1997 (62 FR 960), inviting comment on an updated 
hazardous waste combustor data base containing the emissions and 
ancillary

[[Page 52835]]

data that the Agency used to develop the final rule;
    3. March 21, 1997 (62 FR 13775), inviting comment on our approach 
to demonstrate the technical feasibility of monitoring particulate 
matter emissions from hazardous waste combustors using continuous 
emissions monitoring systems;
    4. May 2, 1997 (62 FR 24212), inviting comment on several topics 
including the status of establishing MACT standards for hazardous waste 
combustors using a revised emissions data base and the status of 
various implementation issues, including compliance dates, compliance 
requirements, performance testing, and notification and reporting 
requirements; and
    5. December 30, 1997 (62 FR 67788), inviting comment on several 
status reports pertaining to particulate matter continuous emissions 
monitoring systems.
    Finally, we have had many formal and informal meetings with 
stakeholders, representing an on-going dialogue on various aspects of 
the rulemaking.
    We carefully considered information and comments submitted by 
stakeholders on these rulemaking actions and during meetings. We 
address their comments in our Response to Comments documents, which can 
be found in the public docket supporting this rulemaking. In addition, 
we addressed certain significant comments at appropriate places in this 
preamble.

Part Two: Which Devices Are Subject to Regulation?

I. Hazardous Waste Incinerators

    Hazardous waste incinerators are enclosed, controlled flame 
combustion devices, as defined in 40 CFR 260.10. These devices may be 
fixed or transportable. Major incinerator designs used in the United 
States are rotary kilns, fluidized beds, liquid injection and fixed 
hearth, while newer designs and technologies are also coming into 
operation. Detailed descriptions of the designs, types of facilities 
and typical air pollution control devices were presented in the April 
1996 NPRM and in the technical background document prepared to support 
the NPRM. (See 61 FR 17361, April 19, 1996.) In 1997, there were 149 
hazardous waste incinerator facilities operating 189 individual units 
in the U.S. Of these 149 facilities, 20 facilities (26 units) were 
commercial hazardous waste incinerators, while the remaining 129 
facilities (163 units) were on-site hazardous waste incinerators.

II. Hazardous Waste Burning Cement Kilns

    Cement kilns are horizontally inclined rotating cylinders, lined 
with refractory-brick, and internally fired. Cement kilns are designed 
to calcine, or drive carbon dioxide out of, a blend of raw materials 
such as limestone, shale, clay, or sand to produce Portland cement. 
When combined with sand, gravel, water, and other materials, Portland 
cement forms concrete, a material used widely in many building and 
construction applications.
    Generally, there are two different processes used to produce 
Portland cement: a wet process and a dry process. In the wet process, 
raw materials are ground, wetted, and fed into the kiln as a slurry. In 
the dry process, raw materials are ground and fed dry into the kiln. 
Wet process kilns are typically longer in length than dry process kilns 
to facilitate water evaporation from the slurried raw material. Dry 
kilns use less energy (heat) and also can use preheaters or 
precalciners to begin the calcining process before the raw materials 
are fed into the kiln.
    A number of cement kilns burn hazardous waste-derived fuels to 
replace some or all of normal fossil fuels such as coal. Most kilns 
burn liquid waste; however, cement kilns also may burn bulk solids and 
small containers containing viscous or solid hazardous waste fuels. 
Containers are introduced either at the upper, raw material end of the 
kiln or at the midpoint of the kiln.
    All existing hazardous waste burning cement kilns use particulate 
matter control devices. These cement plants either use fabric filters 
(baghouses) or electrostatic precipitators to control particulate 
matter.
    In 1997, there were 18 Portland cement plants operating 38 
hazardous waste burning kilns. Of these 38 kilns, 27 kilns use the wet 
process to manufacture cement and 11 kilns use the dry process. Of the 
dry process kilns, one kiln uses a preheater and another kiln used a 
preheater and precalciner. Detailed descriptions of the design types of 
facilities and typical air pollution control devices are presented in 
the technical background document.\11\
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    \11\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume I: Description of Source Categories,'' July 1999.
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    In developing standards, the Agency considered the appropriateness 
of distinguishing among the different types of cement kilns burning 
hazardous waste. We determined that distinguishing subcategories of 
hazardous waste burning cement kilns was not needed to develop uniform, 
achievable MACT standards. (See Part Four, Section VII of the preamble 
for a discussion of subcategory considerations.)

III. Hazardous Waste Burning Lightweight Aggregate Kilns

    The term ``lightweight aggregate'' refers to a wide variety of raw 
materials (such as clay, shale, or slate) that, after thermal 
processing, can be combined with cement to form concrete products. 
Lightweight aggregate concrete is produced either for structural 
purposes or for thermal insulation purposes. A lightweight aggregate 
plant is typically composed of a quarry, a raw material preparation 
area, a kiln, a cooler, and a product storage area. The material is 
taken from the quarry to the raw material preparation area and from 
there is fed into the rotary kiln.
    A rotary kiln consists of a long steel cylinder, lined internally 
with refractory bricks, which is capable of rotating about its axis and 
is inclined horizontally. The prepared raw material is fed into the 
kiln at the higher end, while firing takes place at the lower end. As 
the raw material is heated, it melts into a semiplastic state and 
begins to generate gases that serve as the bloating or expanding agent. 
As temperatures reach their maximum, the semiplastic raw material 
becomes viscous and entraps the expanding gases. This bloating action 
produces small, unconnected gas cells, which remain in the material 
after it cools and solidifies. The product exits the kiln and enters a 
section of the process where it is cooled with cold air and then 
conveyed to the discharge. Kiln operating parameters such as flame 
temperature, excess air, feed size, material flow, and speed of 
rotation vary from plant to plant and are determined by the 
characteristics of the raw material.
    In 1997, there were five lightweight aggregate kiln facilities in 
the United States operating 10 hazardous waste-fired kilns. Detailed 
descriptions of the lightweight aggregate process and air pollution 
control techniques are presented in the technical support document.\12\
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    \12\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume I: Description of Source Categories,'' July 1999.

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[[Page 52836]]

Part Three: How Were the National Emission Standards for Hazardous 
Air Pollutants (NESHAP) in This Rule Determined?

I. What Authority Does EPA Have To Develop a NESHAP?

    The 1990 Amendments to the Clean Air Act (CAA) significantly 
revised the requirements for controlling emissions of hazardous air 
pollutants. EPA is required to develop a list of categories of major 
and area sources of the hazardous air pollutants identified in section 
112 and to develop, over specified time periods, technology-based 
performance standards for sources of these hazardous air pollutants. 
See CAA sections 112(c) and 112(d). These source categories and 
subcategories are to be listed pursuant to section 112(c)(1). We 
published an initial list of 174 categories of such major and area 
sources in the Federal Register on July 16, 1992 (57 FR 31576), which 
was later amended at 61 FR 28197 (June 4, 1996) \13\ and 63 FR 7155 
(February 12, 1998). That list includes the Hazardous Waste 
Incineration, Portland Cement Manufacturing, and Clay Products 
Manufacturing source categories.
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    \13\ A subsequent Notice was published on July 18, 1996 (61 FR 
37542) which corrected typographical errors in the June 4, 1996 
Notice.
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    Promulgation of technology-based standards for these listed source 
categories is not necessarily the final step in the process. CAA 
section 112(f) requires the Agency to report to Congress on the 
estimated risk remaining after imposition of technology-based standards 
and make recommendations as to additional legislation needed to address 
such risk. If Congress does not act on any recommendation presented in 
this report, we are required to impose additional controls if such 
controls are needed to protect public health with an ample margin of 
safety or (taking into account costs, energy, safety, and other 
relevant factors) to prevent adverse environmental effects. In 
addition, if the technology-based standards for carcinogens do not 
reduce the lifetime excess cancer risk for the most exposed individual 
to less than one in a million (1 x 10-6), then we must 
promulgate additional standards.
    We prepared the Draft Residual Risk Report to Congress and 
announced its release on April 22, 1998 (63 FR 19914-19916). In that 
report, we did not propose any legislative recommendation to Congress. 
In section 4.2.4 of the report, we state that: ``The legislative 
strategy embodied in the 1990 CAA Amendments adequately maintains the 
goal of protecting the public health and the environment and provides a 
complete strategy for dealing with a variety of risk problems. The 
strategy recognizes that not all problems are national problems or have 
a single solution. National emission standards will be promulgated to 
decrease the emissions of as many hazardous air pollutants as possible 
from major sources.''

II. What Are the Procedures and Criteria for Development of NESHAPs?

A. Why Are NESHAPs Needed?
    NESHAPs are developed to control hazardous air pollutant emissions 
from both new and existing sources. The statute requires a NESHAP to 
reflect the maximum degree of reduction of hazardous air pollutant 
emissions that is achievable taking into consideration the cost of 
achieving the emission reduction, any nonair quality health and 
environmental impacts, and energy requirements. NESHAPs are often 
referred to as maximum achievable control technology (or MACT) 
standards.
    We are required to develop MACT emission standards based on 
performance of the best control technologies for categories or sub-
categories of major sources of hazardous air pollutants. We also can 
establish lower thresholds for determining which sources are major 
where appropriate. In addition, we may require sources emitting 
particularly dangerous hazardous air pollutants such as particular 
dioxins and furans to control those pollutants under the MACT standards 
for major sources.
    In addition, we regulate area sources by technology-based standards 
if we find that these sources (individually or in the aggregate) 
present a threat of adverse effects to human health or the environment 
warranting regulation. After such a determination, we have a further 
choice whether to require technology-based standards based on MACT or 
on generally achievable control technology.
B. What Is a MACT Floor?
    The CAA directs EPA to establish minimum emission standards, 
usually referred to as MACT floors. For existing sources in a category 
or subcategory with 30 or more sources, the MACT floor cannot be less 
stringent than the ``average emission limitation achieved by the best 
performing 12 percent of the existing sources. * * *'' For existing 
sources in a category or subcategory with less than 30 sources, the 
MACT floor cannot be less stringent than the ``average emission 
limitation achieved by the best performing 5 sources. * * *'' For new 
sources, the MACT floor cannot be ``less stringent than the emission 
control that is achieved by the best controlled similar source. * * *''
    We must consider in a NESHAP rulemaking whether to develop 
standards that are more stringent than the floor, which are referred to 
as ``beyond-the-floor'' standards. To do so, we must consider statutory 
criteria, such as the cost of achieving emission reduction, cost 
effectiveness, energy requirements, and nonair environmental 
implications.
    Section 112(d)(2) specifies that emission reductions may be 
accomplished through the application of measures, processes, methods, 
systems, or techniques, including, but not limited to: (1) Reducing the 
volume of, or eliminating emissions of, such pollutants through process 
changes, substitution of materials, or other modifications; (2) 
enclosing systems or processes to eliminate emissions; (3) collecting, 
capturing, or treating such pollutants when released from a process, 
stack, storage, or fugitive emissions point; (4) design, equipment, 
work practice, or operational standards (including requirements for 
operator training or certification); or (5) any combination of the 
above. See section 112(d)(2).
    Application of techniques (1) and (2) are consistent with the 
definitions of pollution prevention under the Pollution Prevention Act 
and the definition of waste minimization under RCRA. In addition, these 
definitions are in harmony with our Hazardous Waste Minimization and 
Combustion Strategy. These terms have particular applicability in the 
discussion of pollution prevention/waste minimization incentives, which 
were finalized at 63 FR 33782 (June 19, 1998) and which are summarized 
in the permitting and compliance sections of this final rule.
C. How Are NESHAPs Developed?
    To develop a NESHAP, we compile available information and in some 
cases collect additional information about the industry, including 
information on emission source quantities, types and characteristics of 
hazardous air pollutants, pollution control technologies, data from 
emissions tests (e.g., compliance tests, trial burn tests) at 
controlled and uncontrolled facilities, and information on the costs 
and other energy and environmental impacts of emission control 
techniques. We use this information in analyzing and developing 
possible regulatory

[[Page 52837]]

approaches. Of course, we are not always able to assemble the same 
amount of information per industry and typically base the NESHAP on 
information practically available.
    NESHAPs are normally structured in terms of numerical emission 
limits. However, alternative approaches are sometimes necessary and 
appropriate. Section 112(h) authorizes the Administrator to promulgate 
a design, equipment, work practice, or operational standard, or a 
standard that is a combination of these alternatives.

III. How Are Area Sources and Research, Development, and Demonstration 
Sources Treated in This Rule?

A. Positive Area Source Finding for Hazardous Waste Combustors
1. How Are Area Sources Treated in This Rule?
    In today's final rule, we make a positive area source finding 
pursuant to CAA section 112(c)(3) for hazardous waste burning 
incinerators, hazardous waste burning cement kilns, and hazardous waste 
burning lightweight aggregate kilns. This rule subjects both major and 
area sources in these three source categories to the same standards--
the section 112(d) MACT standards. We make this positive area source 
determination because emissions from area sources subject to today's 
rule present a threat of adverse effects to human health and the 
environment. These threats warrant regulation under the section 112 
MACT standards.
2. What Is an Area Source?
    Area sources are sources emitting (or having the potential to emit) 
less than 10 tons per year of an individual hazardous air pollutant, 
and less than 25 tons per year of hazardous air pollutants in the 
aggregate. These sources may be regulated under MACT standards if we 
find that the sources ``presen[t] a threat of adverse effects to human 
health or the environment (by such sources individually or in the 
aggregate) warranting regulation under this section.'' Section 
112(c)(3).
    As part of our analysis, we estimate that all hazardous waste 
burning lightweight aggregate kilns are major sources, principally due 
to their hydrochloric acid emissions. We also estimate that 
approximately 80 percent of hazardous waste burning cement kilns are 
major sources, again due to hydrochloric acid emissions. Only 
approximately 30 percent of hazardous waste burning incinerators appear 
to be major sources, considering only the stack emissions from the 
incinerator. However, major and area source status is determined by the 
entire facility's hazardous air pollutant emissions, so that many on-
site hazardous waste incinerators are major sources because they are 
but one contributing source of emissions among others (sometimes many 
others at large manufacturing complexes) at the same facility.
3. What Is the Basis for Today's Positive Area Source Finding?
    The consequences of us not making a positive area source finding in 
this rule would result in an undesirable bifurcated regulation. First, 
the CAA provides independent authority to regulate certain hazardous 
air pollutant emissions under MACT standards, even if the emissions are 
from area sources. These are the hazardous air pollutants enumerated in 
section 112(c)(6), and include 2,3,7,8 dichlorobenzo-p-dioxins and 
furans, mercury, and some specific polycyclic organic hazardous air 
pollutants--hazardous air pollutants regulated under this rule. See 62 
FR at 24213-24214. Thus, all sources covered by today's rule would have 
to control these hazardous air pollutants to MACT levels, even if we 
were not to make a positive area source determination. Second, because 
all hazardous air pollutants are fully regulated under RCRA, area 
source hazardous waste combustors would have not only a full RCRA 
permit, but also (as just explained) a CAA title V permit for the 
section 112(c)(6) hazardous air pollutants. One purpose of this rule is 
to avoid the administrative burden to sources resulting from this type 
of dual permitting, and these burdensome consequences of not making a 
positive area source finding have influenced our decision that area 
source hazardous waste combustors ``warrant regulation'' under section 
112(d)(2).
    a. Health and Environmental Factors. Our positive area source 
finding is based on the threats presented by emissions of hazardous air 
pollutants from area sources. We find that these threats warrant 
regulation under the MACT standards given the evident Congressional 
intent for uniform regulation of hazardous waste combustion sources, as 
well as the common emission characteristics of these sources and 
amenability to the same emission control mechanisms.
    As discussed in both the April 1996 proposal and May 1997 NODA, all 
hazardous waste combustion sources, including those that may be area 
sources, have the potential to pose a threat of adverse effects to 
human health or the environment, although some commenters disagree with 
this point. These sources emit some of the most toxic, bioaccumulative 
and persistent hazardous air pollutants--among them dioxins, furans, 
mercury, and organic hazardous air pollutants. As discussed in these 
Federal Register notices and elsewhere in today's final rule, potential 
hazardous waste combustor area sources can be significant contributors 
to national emissions of these hazardous air pollutants. (See 62 FR 
17365 and 62 FR 24213.)
    Our positive area source finding also is based on the threat posed 
by products of incomplete combustion. The risks posed by these 
hazardous air pollutants cannot be directly quantified on a national 
basis, because each unit emits different products of incomplete 
combustion in different concentrations. However, among the products of 
incomplete combustion emitted from these sources are potential 
carcinogens.\14\ The potential threat posed by emissions of these 
hazardous air pollutants is manifest and, for several reasons, we do 
not believe that control of these products of incomplete combustion 
should be left to the RCRA omnibus permitting process. First, we are 
minimizing the administrative burden on sources from duplicative 
permitting in this rule by minimizing the extent of RCRA permitting and 
hence minimizing our reliance on the omnibus process. Second, we are 
dealing with hazardous air pollutant emissions from these sources on a 
national rather than a case-by-case basis. We conclude that the control 
of products of incomplete combustion from all hazardous waste 
combustors through state-of-the art organic pollution control is the 
best way to do so from an implementation standpoint. Finally, a basic 
premise of the CAA is that there are so many uncertainties and 
difficulties in developing effective risk-based regulation of hazardous 
air pollutants that the first step should be technology-based standards 
based on Maximum Available Control Technology. See generally S. Rep. 
No. 228, 101st Cong. 1st Sess. 128-32 (1990). The positive area source 
finding and consequent MACT controls is consistent with this primary 
legislative objective.
---------------------------------------------------------------------------

    \14\ E.g., benzene, methylene chloride, hexachlorobenzene, 
carbon tetrachloride, vinal chloride, benzo(a)pyrene, and 
chlorinated dioxins and furans. Energy and Environmental Research 
Corp., surrogate Evaluation for Thermal Treatment Systems, Draft 
Report, October 1994. Also see: USEPA, ``Final technical Support 
Document for HWC MACT Standards, Volume III: Section of MACT 
Standards and Technologies,'' July 1999.
---------------------------------------------------------------------------

    The quantitative risk assessment for the final rule did not find 
risk from

[[Page 52838]]

mercury emissions from hazardous waste burning area source cement kilns 
to be above levels we generally consider acceptable. However, the 
uncertainties underlying the analysis are such that only qualitative 
judgments can be made. We do not believe our analysis can be relied 
upon to make a definitive quantitative finding about the precise 
magnitude of the risk. See Part Five, Section XIII for a discussion of 
uncertainty. Background exposures, which can be quite variable, were 
not considered in the quantitative assessment and are likely to 
increase the risk from incremental exposures to mercury from area 
source cement kilns. Commenters, on the other hand, believed that 
cement kilns did not pose significant risk and questioned our risk 
estimates made in the April 1996 NPRM and May 1997 NODA. However, 
taking into account the uncertainty of our mercury analysis and the 
likelihood of background exposures, a potential for risk from mercury 
may exist. Furthermore, the information available concerning the 
adverse human health effects of mercury, along with the magnitude of 
the emissions of mercury from area source cement kilns, also indicate 
that a threat of adverse effects is presumptive and that a positive 
area source finding is warranted.
    b. Other Reasons Warranting Regulation under Section 112. Other 
special factors indicate that MACT standards are warranted for these 
sources.
    The first reason is Congress's, our, and the public's strong 
preference for similar, if not identical, regulation of all hazardous 
waste combustors. Area sources are currently regulated uniformly under 
RCRA, with no distinction being made between smaller and larger 
emitters. This same desire for uniformity is reflected in the CAA. CAA 
section 112(n)(7) directs the Agency, in its regulation of HWCs under 
RCRA, to ``take into account any regulations of such emissions which 
are promulgated under such subtitle (i.e., RCRA) and shall, to the 
maximum extent practicable and consistent with the provisions of this 
section, ensure that the requirements of such subtitle and this section 
are consistent.'' Congress also dealt with these sources as a single 
class by excluding hazardous waste combustion units regulated by RCRA 
permits from regulation as municipal waste combustors under CAA section 
129(g)(1). Thus, a strong framework in both statutes indicates that air 
emissions from all hazardous waste combustors should be regulated under 
a uniform approach. Failure to adopt such a uniform approach would 
therefore be inconsistent with Congressional intent as expressed in 
both the language and the structure of RCRA and the CAA. Although many 
disagree, several commenters support the approach to apply uniform 
regulations for all hazardous waste combustors and assert that it is 
therefore appropriate and necessary to make the positive area source 
finding.
    Second, a significant number of hazardous waste combustors could 
plausibly qualify as area sources by the compliance date through 
emissions reductions of one or more less dangerous hazardous air 
pollutants, such as total chlorine. We conclude it would be 
inappropriate to exclude from CAA 112(d) regulation and title V 
permitting a significant portion of the sources contributing to 
hazardous air pollutant emissions, particularly nondioxin products of 
incomplete combustion should this occur.
    Third, the MACT controls identified for major sources are 
reasonable and appropriate for potential area sources. The emissions 
control equipment (and where applicable, feedrate control) defined as 
floor or beyond-the-floor control for each source category is 
appropriate and can be installed and operated at potential area 
sources. There is nothing unique about the types and concentrations of 
emissions of hazardous air pollutants from any class of hazardous waste 
combustors that would make MACT controls inappropriate for that 
particular class of hazardous waste combustors, but not the others. 
Commenters also raised the issue of applying generally available 
control technologies (GACT), in lieu of MACT, to area sources. 
Consideration of GACT lead us to the conclusion that GACT would likely 
involve the same types and levels of control as we identified for MACT. 
We believe GACT would be the same as MACT because the standards of this 
rule, based on MACT, are readily achievable, and therefore would also 
be determined to be generally achievable, i.e., GACT.
    Finally, we note that the determination here is unique to these 
RCRA sources, and should not be viewed as precedential for other CAA 
sources. In the language of the statute, there are special reasons that 
these RCRA sources warrant regulation under section 112(d)(2)--and so 
warrant a positive area source finding--that are not present for usual 
CAA sources. These reasons are discussed above--the Congressional 
desire for uniform regulation and our desire (consistent with this 
Congressional objective) to avoid duplicative permitting of these 
sources wherever possible. We repeat, however, that the positive area 
source determination here is not meant as a precedent outside the dual 
RCRA/CAA context.
B. How Are Research, Development, and Demonstration (RD&D) Sources 
Treated in This Rule?
    Today's rule excludes research, development, and demonstration 
sources from the hazardous waste burning incinerator, cement kiln, and 
lightweight aggregate kiln source categories. We discuss below the 
statutory mandate to give special consideration to research and 
development (R&D) sources, an Advanced Notice of Proposed Rulemaking to 
list R&D facilities that we published in 1997, and qualifications for 
exclusion of R&D sources from the hazardous waste combustor source 
categories.
1. Why Does the CAA Give Special Consideration to Research and 
Development (R&D) Sources?
    Section 112(c)(7) of the Clean Air Act requires EPA to ``establish 
a separate category covering research or laboratory facilities, as 
necessary to assure the equitable treatment of such facilities.'' 
Congress included such language in the Act because it was concerned 
that research and laboratory facilities should not arbitrarily be 
included in regulations that cover manufacturing operations. The Act 
defines a research or laboratory facility as ``any stationary source 
whose primary purpose is to conduct research and development into new 
processes and products, where such source is operated under the close 
supervision of technically trained personnel and is not engaged in the 
manufacture of products for commercial sale in commerce, except in a de 
minimis manner.''
    We interpret the Act as requiring the listing of R&D major sources 
as a separate category to ensure equitable treatment of such 
facilities. Language in the Act specifying special treatment of R&D 
facilities (section 112(c)(7)), along with language in the legislative 
history of the Act, suggests that Congress considered it inequitable to 
subject the R&D facilities of an industry to a standard designed for 
the commercial production processes of that industry. The application 
of such a standard may be inappropriate because the wide range of 
operations and sizes of R&D facilities. Further, the frequent changes 
in R&D operations may be significantly different from the typically 
large and continuous production processes.
    We have no information indicating that there are R&D sources, major 
or

[[Page 52839]]

area, that are required to be listed and regulated, other than those 
associated with sources already included in listed source categories 
listed today. Although we are not aware of other R&D sources that need 
to be added to the source category list, such sources may exist, and we 
requested information about them in an Advance Notice of Proposed 
Rulemaking, as discussed in the next section.
2. When Did EPA Notice Its Intent To List R&D Facilities?
    In May 1997 (62 FR 25877), we provided advanced notice that we were 
considering whether to list R&D facilities. We requested public 
comments and information on the best way to list and regulate such 
sources. Comment letters were received from industry, academic 
representatives, and governmental entities. After we compile additional 
data, we will respond to these comments in that separate docket. As a 
result we are not deciding how to address the issue in today's rule. 
The summary of comments and responses will be one part of the basis for 
our future decision whether to list R&D facilities as a source category 
of hazardous air pollutants.
3. What Requirements Apply to Research, Development, and Demonstration 
Hazardous Waste Combustor Sources?
    This rule excludes research, development, and demonstration sources 
from the hazardous waste incinerator, cement kiln, or lightweight 
aggregate kiln source categories and therefore from compliance with 
today's regulations. We are excluding research, development, and 
demonstration sources from those source categories because the emission 
standards and compliance assurance requirements for those source 
categories may not be appropriate. The operations and size of a 
research, development, and demonstration source may be significantly 
different from the typical hazardous waste incinerator that is 
providing ongoing waste treatment service or hazardous waste cement 
kiln or hazardous waste lightweight aggregate kiln that is producing a 
commercial product as well as providing ongoing waste treatment.
    We also are applying the exclusion to demonstration sources because 
demonstration sources are operated more like research and development 
sources than production sources. Thus, the standards and requirements 
finalized today for production sources may not be appropriate for 
demonstration sources. Including demonstration sources in the exclusion 
is consistent with our current regulations for hazardous waste 
management facilities. See Sec. 270.65 providing opportunity for 
special operating permits for research, development, and demonstration 
sources that use an innovative and experimental hazardous waste 
treatment technology or process.
    To ensure that research, development, and demonstration sources are 
distinguished from production sources, we have drawn from the language 
in section 112(c)(7) to define a research, development, and 
demonstration source. Specifically, these are sources engaged in 
laboratory, pilot plant, or prototype demonstration operations: (1) 
Whose primary purpose is to conduct research, development, or short-
term demonstration of an innovative and experimental hazardous waste 
treatment technology or process; and (2) where the operations are under 
the close supervision of technically-trained personnel.15
---------------------------------------------------------------------------

    \15\The statute also qualifies that research and development 
sources do not engage in the manufacture of products for commercial 
sale except in a de minimis manner. Although this qualification is 
appropriate for research and development sources, engaged in short-
term demonstration of an innovative or experimental treatment 
technology or process may produce products for use in commerce. For 
example, a cement kiln engaged in a short-term demonstration of an 
innovative process may nonetheless produce marketable clinker in 
other than de minimis quantities. Consequently, we are not including 
this qualification in the definition of a research, development, and 
demonstration source.
---------------------------------------------------------------------------

    In addition, today's rule limits the exclusion to research, 
development, and demonstration sources that operate for not longer than 
one year after first processing hazardous waste, unless the 
Administrator grants a time extension based on documentation that 
additional time is needed to perform research development, and 
demonstration operations. We believe that this time restriction will 
help distinguish between research, development, and demonstration 
sources and production sources. This time restriction draws from the 
one-year time restriction (unless extended on a case-by-case basis) 
currently applicable to hazardous waste research, development, and 
demonstration sources under Sec. 270.65.
    The exclusion of research, development, and demonstration sources 
applies regardless of whether the sources are located at the same site 
as a production hazardous waste combustor that is subject to the MACT 
standards finalized today. A research, development, and demonstration 
source that is co-located at a site with a production source still 
qualifies for the exclusion. A research, development, and demonstration 
source co-located with a production source is nonetheless expected to 
experience the type and range of operations and be of the size typical 
for other research, development, and demonstration sources.
    Finally, hazardous waste research, development, and demonstration 
sources remain subject to RCRA permit requirements under Sec. 270.65, 
which direct the Administrator to establish permit terms and conditions 
that will assure protection of human health and the environment.
    Although we did not propose this exclusion specifically for 
hazardous waste combustor research, development, and demonstration 
sources, the exclusion is an outgrowth of the May 1997 notice discussed 
above. In that notice we explain that we interpret the CAA as requiring 
the listing of research and development major sources as a separate 
category to ensure equitable treatment of such facilities. A commenter 
on the April 1996 hazardous waste combustor NPRM questioned whether we 
intended to apply the proposed regulations to research and development 
sources. We did not have that intent, and in response are finalizing 
today an exclusion of research, development, and demonstration sources 
from the hazardous waste incinerator, hazardous waste burning cement 
kiln, and hazardous waste burning lightweight aggregate kiln source 
categories.

IV. How Is RCRA's Site-Specific Risk Assessment Decision Process 
Impacted by This Rule?

    RCRA Sections 3004(a) and (q) mandate that standards governing the 
operation of hazardous waste combustion facilities be protective of 
human health and the environment. To meet this mandate, we developed 
national combustion standards under RCRA, taking into account the 
potential risk posed by direct inhalation of the emissions from these 
sources.16 With advancements in the assessment of risk since 
promulgation of the original national standards (i.e., 1981 for 
incinerators and 1991 for boilers and industrial furnaces), we 
recognized in the 1993 Hazardous Waste Minimization and Combustion 
Strategy that additional risk analysis was appropriate. Specifically, 
we noted that the risk posed by indirect exposure (e.g., ingestion of 
contamination in the food chain) to long-term deposition of metals,

[[Page 52840]]

dioxin/furans and other organic compounds onto soils and surface waters 
should be assessed in addition to the risk posed by direct inhalation 
exposure to these contaminants. We also recognized that the national 
assessments performed in support of the original hazardous waste 
combustor standards did not take into account unique and site-specific 
considerations which might influence the risk posed by a particular 
source. Therefore, to ensure the RCRA mandate was met on a facility-
specific level for all hazardous waste combustors, we strongly 
recommended in the Strategy that site-specific risk assessments 
(SSRAs), including evaluations of risk resulting from both direct and 
indirect exposure pathways, be conducted as part of the RCRA permitting 
process. In those situations where the results of a SSRA showed that a 
facility's operations could pose an unacceptable risk (even after 
compliance with the RCRA national regulatory standards), additional 
risk-based, site-specific permit conditions could be imposed pursuant 
to RCRA's omnibus authority (section 3005(c)(3)).
---------------------------------------------------------------------------

    \16\ See No CFR part 264, subpart O for incinerator standards 
and 40 CFR part 266, subpart H for BIF standards.
---------------------------------------------------------------------------

    Today's MACT standards were developed pursuant to section 112(d) of 
the CAA, which does not require a concurrent risk evaluation of those 
standards. To determine if the MACT standards would satisfy the RCRA 
protectiveness mandate in addition to the requirements of the CAA, we 
conducted a national RCRA evaluation of both direct and indirect risk 
as part of this rulemaking. If we found the MACT standards to be 
sufficiently protective so as to meet the RCRA mandate as well, we 
could consider modifying our general recommendation that SSRAs be 
conducted for all hazardous waste combustors, thereby lessening the 
regulatory burden to both permitting authorities and facilities.
    In this section, we discuss: The applicability of both the RCRA 
omnibus authority and the SSRA policy to hazardous waste combustors 
subject to today's rulemaking; the implementation of the SSRA policy; 
the relationship of the SSRA policy to the residual risk requirement of 
section 112(f) of the CAA; and public comments received on these 
topics. A discussion of the national risk characterization methodology 
and results is provided in Part Five, Section XIII of today's notice.
A. What Is the RCRA Omnibus Authority?
    Section 3005(c)(3) of RCRA (codified at 40 CFR 270.32(b)(2)) 
requires that each hazardous waste facility permit contain the terms 
and conditions necessary to protect human health and the environment. 
This provision is commonly referred to as the ``omnibus authority'' or 
``omnibus provision.'' It is the means by which additional site-
specific permit conditions may be incorporated into RCRA permits should 
such conditions be necessary to protect human health and the 
environment.17 SSRAs have come to be used by permitting 
authorities as a quantitative basis for making omnibus determinations 
for hazardous waste combustors.
---------------------------------------------------------------------------

    \17\ The risk-based permit conditions are in addition to those 
conditions required by the RCRA national regulatory standards for 
hazardous waste combustors (e.g., general facility requirements).
---------------------------------------------------------------------------

    In the April 1996 NPRM and May 1997 NODA, we discussed the RCRA 
omnibus provision and its relation to the new MACT standards. 
Commenters question whether the MACT standards supersede the omnibus 
authority with respect to hazardous waste combustor air emissions. 
Other commenters agree in principle with the continued applicability of 
the omnibus authority after promulgation of the MACT standards. These 
commenters recognize that there may be unique conditions at a given 
site that may warrant additional controls to those specified in today's 
notice. For those sources, the commenters acknowledge that permit 
writers must retain the legal authority to place additional operating 
limitations in a source's permit.
    As noted above, the omnibus provision is a RCRA statutory 
requirement and does not have a CAA counterpart. The CAA does not 
override RCRA. Each statute continues to apply to hazardous waste 
combustors unless we determine there is duplication and use the RCRA 
section 1006(b) deferral authority to create a specific regulatory 
exemption.18 Promulgation of the MACT standards, therefore, 
does not duplicate, supersede, or otherwise modify the omnibus 
provision or its applicability to sources subject to today's 
rulemaking. As indicated in the April 1996 NPRM, a RCRA permitting 
authority (such as a state agency) has the responsibility to supplement 
the national MACT standards as necessary, on a site-specific basis, to 
ensure adequate protection under RCRA. We recognize that this could 
result in a situation in which a source may be subject to emission 
standards and operating conditions under two regulatory authorities 
(i.e., CAA and RCRA). Although our intent, consistent with the 
integration provision of RCRA section 1006(b), is to avoid regulatory 
duplication to the maximum extent practicable, we may not eliminate 
RCRA requirements if a source's emissions are not protective of human 
health and the environment when complying with the MACT 
standards.19
---------------------------------------------------------------------------

    \18\ The risk-based permit conditions are in addition to those 
conditions required by the RCRA national regulatory standards for 
hazardous waste combustors (e.g., general facility requirements).
    \19\ RCRA section 1006(b) authorizes deferral of RCRA provisions 
to other EPA-implemented authorities provided, among other things, 
that key RCRA policies and protections are not sacrificed. See 
Chemical Waste Management v. EPA, 976 F. 2d 2, 23, 25 (D.C. Cir. 
1992).
---------------------------------------------------------------------------

B. How Will the SSPA Policy Be Applied and Implemented in Light of This 
Mandate?
1. Is There a Continuing Need for Site-Specific Risk Assessments?
    As stated previously, EPA's Hazardous Waste Minimization and 
Combustion Strategy recommended that SSRAs be conducted as part of the 
RCRA permitting process for hazardous waste combustors where necessary 
to protect human health and the environment. We intended to reevaluate 
this policy once the national hazardous waste combustion standards had 
been updated. We view today's MACT standards as more stringent than 
those earlier standards for incinerators, cement kilns and lightweight 
aggregate kilns. To determine if the MACT standards as proposed in the 
April 1996 NPRM would satisfy the RCRA mandate to protect human health 
and the environment, we conducted a national evaluation of both human 
health and ecological risk. That evaluation, however, did not 
quantitatively assess the proposed standards with respect to mercury 
and nondioxin products of incomplete combustion. This was due to a lack 
of adequate information regarding the behavior of mercury in the 
environment and a lack of sufficient emissions data and parameter 
values (e.g., bioaccumulation values) for nondioxin products of 
incomplete combustion. Since it was not possible to suitably evaluate 
the proposed standards for the potential risk posed by mercury and 
nondioxin products of incomplete combustion, we elected in the April 
1996 NPRM to continue recommending that SSRAs be conducted as part of 
the permitting process until we could conduct a further assessment once 
final MACT standards are promulgated and implemented.
    Although some commenters agree with this approach, a number of 
other commenters question the necessity of a quantitative nondioxin 
product of incomplete combustion assessment to demonstrate RCRA 
protectiveness of the MACT standards. These commenters

[[Page 52841]]

assert that existing site-specific assessments demonstrate that 
emissions of nondioxin products of incomplete combustion are unlikely 
to produce significant adverse human health effects. However, we do not 
agree that sufficient SSRA information exists to conclude that 
emissions from these compounds are unlikely to produce significant 
adverse effects on human health and the environment on a national 
basis. First, only a limited number of completed SSRAs are available 
from which broader conclusions can be drawn. Second, nondioxin products 
of incomplete combustion emissions can vary widely depending on the 
type of combustion unit, hazardous waste feed and air pollution control 
device used. Third, a significant amount of uncertainty exists with 
respect to identifying and quantifying these compounds. Many nondioxin 
products of incomplete combustion cannot be characterized by standard 
analytical methodologies and are unaccounted for by standard emissions 
testing.20 (On a site-specific basis, uncharacterized 
nondioxin products of incomplete combustion are typically addressed by 
evaluating the total organic emissions.) Fourth, nondioxin products of 
incomplete combustion can significantly contribute to the overall risk 
posed by a particular facility. For example, in the Waste Technologies 
Industries incinerator's SSRA, nondioxin organics were estimated to 
contribute approximately 30% of the total cancer risk to the most 
sensitive receptor located in the nearest subarea to the 
facility.21 Fifth, national risk management decisions 
concerning the protectiveness of the MACT standards must be based on 
data that are representative of the hazardous waste combustors subject 
to today's rulemaking. We do not believe that the information afforded 
by the limited number of SSRAs now available is sufficiently complete 
or representative to render a national decision.22
---------------------------------------------------------------------------

    \20\ USEPA, ``Development of a Hazardous Waste Incinerator 
Target Analyte List of Products of Incomplete Combustion'' EPA-600/
R-98-076. 1998.
    \21\ The total cancer risk for this receptor was 1 x 10E-6. The 
results derived for the Waste Technologies Industries incinerator's 
SSRA are a combination of measurements and conservative estimates of 
stack and fugitive emissions, which were developed in tandem with an 
independent external peer review. USEPA, ``Risk Assessment for the 
Waste Technologies Industries Hazardous Waste Incineration Facility 
(East Livepool, Ohio)'' EPA-905-R97-002.
    \22\ Since publication of the April 1996 NPRM, we have expanded 
our national risk evaluation of the other hazardous waste combustor 
emissions (e.g., metals) from 11 facilities to 76 facilities 
assessed for today's final rulemaking. The 76 facilities were 
selected using a stratified random sampling approach that allowed 
for a 90 percent probability of including at least one ``high risk'' 
facility. However, this larger set of facility assessments does not 
include an evaluation nondioxin products of incomplete combustion. 
See Part Five, Section XIII for further discussion.
---------------------------------------------------------------------------

    Some commenters recommend discontinuing conducting SSRAs 
altogether. Other commenters, however, advocate continuing to conduct 
SSRAs, where warranted, as a means of addressing uncertainties inherent 
in the national risk evaluation and of addressing unique, site-specific 
circumstances not considered in the assessment.
    In developing the national risk assessment for the final MAC 
standards, we expanded our original analysis to include a quantitative 
assessment of mercury patterned after the recently published Mercury 
Study Report to Congress.23 We were unable to perform a 
similar assessment of nondioxin products of incomplete combustion 
emissions because of continuing data limitations for these compounds, 
despite efforts to collect additional data since publication of the 
April 1996 NPRM . Thus, we conclude that sufficient data are not 
available to quantitatively assess the potential risk from these 
constituents on a national level as part of today's rulemaking.
---------------------------------------------------------------------------

    \23\ USEPA, ``Mercury Study Report to Congress, Volume III: Fate 
and Transport of Mercury in the Environment,'' EPA 452/R-97-005, 
December 1997.
---------------------------------------------------------------------------

    Given the results of the final national risk assessment for other 
hazardous air pollutants, we generally anticipate that sources 
complying with the MACT standards will not pose an unacceptable risk to 
human health or the environment. However, we cannot make a definitive 
finding in this regard for all hazardous waste combustors subject to 
today's MACT standards for the reasons discussed.
    First, as discussed above, the national risk evaluation did not 
include an assessment of the risk posed by nondioxin products of 
incomplete combustion. As reflected in the Waste Technologies 
Industries SSRA, these compounds can significantly contribute to the 
overall risk posed by a hazardous waste combustor. Without a 
quantitative evaluation of these compounds, we cannot reliably predict 
whether the additional risk contributed by nondioxin products of 
incomplete combustion would or would not result in an unacceptable 
increase in the overall risk posed by hazardous waste combustors 
nationally.
    Second, the quantitative mercury risk analysis conducted for 
today's rulemaking contains significant uncertainties. These 
uncertainties limit the use of the analysis for drawing quantitative 
conclusions regarding the risks associated with the national mercury 
MACT standard. Among others, the uncertainties include an incomplete 
understanding of the fate and transport of mercury in the environment 
and the biological significance of exposures to mercury in fish. (See 
Part Five, Section XIII.) Given these uncertainties, we believe that 
conducting a SSRA, which will assist a permit writer to reduce 
uncertainty on a site-specific basis, may be still warranted in some 
cases.24 As the science regarding mercury fate and transport 
in the environment and exposure improves, and greater certainty is 
achieved in the future, we may be in a better position from which to 
draw national risk management conclusions regarding mercury risk.
---------------------------------------------------------------------------

    \24\ An example of the possible reduction in uncertainty which 
may be derived through the performance of a SSRA includes the degree 
of conversion of mercury to methyl mercury in water bodies. Due to 
the wide range of chemical and physical properties associated with 
surface water bodies, there appears to be a great deal of 
variability concerning mercury methylation. In conducting a SSRA, a 
risk assessor may choose to use a default value to represent the 
percentage of mercury assumed to convert to methyl mercury. 
Conversely, the risk assessor may choose to reduce the uncertainty 
in the analysis by deriving a site-specific value using actual 
surface water data. Chemical and physical properties that may 
influence mercury methylation include, but are not limited to: 
dissolved oxygen content, pH, dissolved organic content, salinity, 
nutrient concentrations, and temperature. See USEPA, ``Human Health 
Risk Assessment Protocol for Hazardous Waste Combustion 
Facilities,'' EPA-530-D-98-001A, External Peer Review Draft, 1998.
---------------------------------------------------------------------------

    Third, we agree with commenters who indicated that, by its very 
nature, the national risk assessment, while comprehensive, cannot 
address unique, site-specific risk considerations \25\ As a result of 
these considerations, a separate analysis or ``risk check'' may be 
necessary to verify that the MACT standards will be adequately 
protective under RCRA for a given hazardous waste combustor.
---------------------------------------------------------------------------

    \25\ Including for example, unusual terrain or dispersion 
features, particularly sensitive ecosystems, unusually high 
contaminant background concentrations, and mercury methylation rates 
in surface water.
---------------------------------------------------------------------------

    Thus, we are recommending that for hazardous waste combustors 
subject to the Phase I final MACT standards, permitting authorities 
should evaluate the need for a SSRA on a case-by-case 
basis.26 SSRAs are not anticipated to be necessary for every 
facility, but should be conducted for facilities where there is some 
reason to believe that operation

[[Page 52842]]

in accordance with the MACT standards alone may not be protective of 
human health and the environment. If a SSRA does demonstrate that 
operation in accordance with the MACT standards may not be protective 
of human health and the environment, permitting authorities may require 
additional conditions as necessary. We consider this an appropriate 
course of action to ensure protection of human health and the 
environment under RCRA, given current limits to our scientific 
knowledge and risk assessment tools.
---------------------------------------------------------------------------

    \26\ We continue to recommend that for those HWCs not subject to 
the Phase I final MACT standards, as SSRA should be conducted as 
part of the RCRA permitting process.
---------------------------------------------------------------------------

2. How Will the SSRA Policy Be Implemented?
    Some commenters suggest that EPA provide regulatory language 
specifically requiring SSRAs. Adequate authority and direction already 
exists to require SSRAs on a case-by-case basis through current 
regulations and guidance (none of which are being reconsidered, revised 
or otherwise reopened in today's rulemaking). The omnibus provision 
(codified in 40 CFR 270.32(b)(2)) directs the RCRA permitting authority 
to include terms and conditions in the RCRA permit as necessary to 
ensure protection of human health and the environment. Under 40 CFR 
270.10(k), the permitting authority may require a permittee or permit 
applicant to submit information where the permitting authority has 
reason to believe that additional permit conditions may be warranted 
under Sec. 270.32(b)(2). Performance of a SSRA is a primary, although 
not exclusive mechanism by which the permitting authority may develop 
the information necessary to make the determination regarding what, if 
any, additional permit conditions are needed for a particular hazardous 
waste combustor. Thus, for hazardous waste combustors, the information 
required to establish permit conditions could include a SSRA, or the 
necessary information required to conduct a SSRA.
    In 1994, we provided guidance concerning the appropriate 
methodologies for conducting hazardous waste combustor 
SSRAs.27 This guidance was updated in 1998 and released for 
publication as an external peer review draft.28 We 
anticipate that use of the updated and more detailed guidance will 
result in a more standardized assessments for hazardous waste 
combustors.
---------------------------------------------------------------------------

    \27\ USEPA. ``Guidance for Performing Screening Level Risk 
Analyses at Combustion Facilities Burning Hazardous Wastes'' Draft, 
April 1994; USEPA. ``Implementation of Exposure Assessment Guidance 
for RCRA Hazardous Waste Combustion Facilities'' Draft, 1994.
    \28\ USEPA. ``Human Health Risk Assessment Protocol for 
Hazardous Waste Combustion Facilities'' EPA-520-D-98-001A, B&C. 
External Peer Review Draft, 1998.
---------------------------------------------------------------------------

    To implement the RCRA SSRA policy, we expect permitting authorities 
to continue evaluating the need for an individual hazardous waste 
combustor risk assessment on a case-by-case basis. We provided a list 
of qualitative guiding factors in the April 1996 NPRM to assist in this 
determination. One commenter is concerned that the subjectivity 
inherent in the list of guiding factors might lead to inconsistencies 
when determining if a SSRA is necessary and suggested that we provide 
additional guidance on how the factors should be used. We continue to 
believe that the factors provided, although qualitative, generally are 
relevant to the risk potential of hazardous waste combustors and 
therefore should be considered when deciding whether or not a SSRA is 
necessary. However, as a practical matter, the complexity of the 
multipathway risk assessment methodology precludes conversion of these 
qualitative factors into more definitive criteria. We will continue to 
compile data from SSRAs to determine if there are any trends which 
would assist in developing more quantitative or objective criteria for 
deciding on the need for a SSRA at any given site. In the interim, 
SSRAs provide the most credible basis for comparisons between risk-
based emission limits and the MACT standards.
    The commenter further suggests that EPA emphasize that the factors 
should be considered collectively due to their complex interplay (e.g., 
exposure is dependent on fate and transport which is dependent on 
facility characteristics, terrain, meteorological conditions, etc.). We 
agree with the commenter. The elements comprising multipathway risk 
assessments are highly integrated. Thus, the considerations used in 
determining if a SSRA is necessary are similarly interconnected and 
should be evaluated collectively.
    The guiding factors as presented in the April 1996 NPRM contained 
several references to the proposed MACT standards. As a result, we 
modified and updated the list to reflect promulgation of the final 
standards and to re-focus the factors to specifically address the types 
of considerations inherent in determining if a SSRA is necessary. The 
revised guiding factors are: (1) Particular site-specific 
considerations such as proximity to receptors, unique dispersion 
patterns, etc.; (2) identities and quantities of nondioxin products of 
incomplete combustion most likely to be emitted and to pose significant 
risk based on known toxicities (confirmation of which should be made 
through emissions testing); (3) presence or absence of other off-site 
sources of pollutants in sufficient proximity so as to significantly 
influence interpretation of a facility-specific risk assessment; (4) 
presence or absence of significant ecological considerations, such as 
high background levels of a particular contaminant or proximity of a 
particularly sensitive ecological area; (5) volume and types of wastes 
being burned, for example wastes containing highly toxic constituents 
both from an acute and chronic perspective; (6) proximity of schools, 
hospitals, nursing homes, day care centers, parks, community activity 
centers that would indicate the presence of potentially sensitive 
receptors; (7) presence or absence of other on-site sources of 
hazardous air pollutants so as to significantly influence 
interpretation of the risk posed by the operation of the source in 
question; and (8) concerns raised by the public. The above list of 
qualitative guiding factors is not intended to be all-inclusive; we 
recognize that there may be other factors equally relevant to the 
decision of whether or not a SSRA is warranted in particular 
situations.
    With respect to existing hazardous waste combustion sources, we do 
not anticipate a large number of SSRAs will need to be performed after 
the compliance date of the MACT standards. SSRAs already have been 
initiated for many of these sources. We strongly encourage facilities 
and permitting authorities to ensure that the majority of those risk 
assessments planned or currently in progress be completed prior to the 
compliance date of the MACT standards. The results of these assessments 
can be used to provide a numerical baseline for emission limits. This 
baseline then can be compared to the MACT limits to determine if site-
specific risk-based limits are appropriate in addition to the MACT 
limits for a particular source.
    Several commenters suggest that completed risk assessments should 
not have to be repeated. We do not anticipate repeating many risk 
assessments. It should be emphasized that changes to comply with the 
MACT standards should not cause an increase in risk for the vast 
majority of the facilities given that the changes, in all probability, 
will be the addition of pollution control equipment or a reduction in 
the hazardous waste being burned. For those few situations in which the 
MACT requirements might result in increased potential risk for a 
particular facility due to unique site-specific considerations, the 
RCRA permit writer, however, may determine

[[Page 52843]]

that a risk check of the projected MACT emission rates is in 
order.29 Should the results of the risk check demonstrate 
that compliance with the MACT requirements does not satisfy the RCRA 
protectiveness mandate, the permitting authority should invoke the 
omnibus provision to impose more stringent, site-specific, risk-based 
permit conditions as necessary to protect human health and the 
environment.
---------------------------------------------------------------------------

    \29\ For example, hazardous waste burning cement kilns that 
previously monitored hydrocarbons in the main stack may elect to 
install a mid-kiln sampling port for carbon monoxide or hydrocarbon 
monitoring to avoid restrictions on hydrocarbon levels in the main 
stack. Thus, their stack hydrocarbon emissions may increase.
---------------------------------------------------------------------------

    With respect to new hazardous waste combustors and existing 
combustors for which a SSRA has never been conducted, we recommend that 
the decision of whether or not a SSRA is necessary be made prior to the 
approval of the MACT comprehensive performance test protocol, thereby 
allowing for the collection of risk emission data at the same time as 
the MACT performance testing, if appropriate (see Part Five, Section 
V). In those instances where it has been determined a SSRA is 
appropriate, the assessment should take into account both the MACT 
standards and any relevant site-specific considerations.
    We emphasize that the incorporation of site-specific, risk-based 
permit conditions into a permit is not anticipated to be necessary for 
the vast majority of hazardous waste combustors. Rather, such 
conditions would be necessary only if compliance with the MACT 
requirements is insufficient to protect human health and the 
environment pursuant to the RCRA mandate and if the resulting risk-
based conditions are more stringent than those required under the CAA. 
Risk-based permit conditions could include, but are not limited to, 
more stringent emission limits, additional operating parameter limits, 
waste characterization and waste tracking requirements.
C. What Is the Difference Between the RCRA SSRA Policy and the CAA 
Residual Risk Requirement?
    Section 112(f) of the CAA requires the Agency to conduct an 
evaluation of the risk remaining for a particular source category after 
compliance with the MACT standards. This evaluation of residual risk 
must occur within eight years of the promulgation of the MACT standards 
for each source category. If it is determined that the residual risk is 
unacceptable, we must impose additional controls on that source 
category to protect public health with an ample margin of safety and to 
prevent adverse environmental effects.
    Our SSRA policy is intended to address the requirements of the RCRA 
protectiveness mandate, which are different from those provided in the 
CAA. For example, the omnibus provision of RCRA requires that the 
protectiveness determination be made on a permit-by-permit or site-
specific basis. The CAA residual risk requirement, conversely, requires 
a determination be made on a source category basis. Further, the time 
frame under which the RCRA omnibus determination is made is more 
immediate; the SSRA is generally conducted prior to final permit 
issuance. The CAA residual risk determination, on the other hand, is 
made at any time within the eight-year time period after promulgation 
of the MACT standards for a source category. Thus, the possibility of a 
future section 112(f) residual risk determination does not relieve RCRA 
permit writers of the present obligation to determine whether the RCRA 
protectiveness requirement is satisfied. Finally, nothing in the RCRA 
national risk evaluation for this rule should be taken as establishing 
a precedent for the nature or scope of any residual risk procedure 
under the CAA.

Part Four: What Is the Rationale for Today's Final Standards?

I. Emissions Data and Information Data Base

A. How Did We Develop the Data Base for This Rule?
    To support the emissions standards in today's rule, we use a 
``fourth generation'' data base that considers and incorporates public 
comments on previous versions of the data base. This final data base 
24 summarizes emissions data and ancillary information on 
hazardous waste combustors that was primarily extracted from 
incinerator trial burn reports and cement and lightweight aggregate 
kiln Certification of Compliance test reports prepared as part of the 
compliance process for the current regulatory standards. Ancillary 
information in the data base includes general facility information 
(e.g., location) process operating data (e.g., waste, fuel, raw 
material compositions, feed rates), and facility equipment design and 
operational information (e.g., air pollution control device 
temperatures).
---------------------------------------------------------------------------

    \24\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume II: HWC Emissions Database,'' July 1999.
---------------------------------------------------------------------------

    The data base supporting the April 1996 proposal was the initial 
data base released for public comment.25 We received a 
substantial number of public comments on this data base including 
identification of data errors and submission of many new trial burn and 
compliance test reports not already in the data base. Subsequently, we 
developed a ``second generation'' data base addressing these comments 
and, on January 7, 1997, published a NODA soliciting public comment on 
the updated data base. Numerous industry stakeholders submitted 
comments on the second generation data base. The data base was revised 
again to accommodate these public comments resulting in a ``third 
generation'' data base. We also published for comment a document 
indicating how specific public comments submitted in response to the 
January NODA were addressed.26 In the May 1997 NODA, we used 
this third generation data base to re-evaluate the MACT standards. 
Since the completion of the third generation data base, we have 
incorporated additional data base comments and new test reports 
resulting in the ``fourth generation'' data base. This final data base 
is used to support all MACT analyses discussed in today's rule. 
Compared to the changes made to develop the third generation data base, 
those changes made in the fourth generation are relatively minor. The 
majority of these changes (e.g., incorporating a few trial burn reports 
and incorporating suggested revisions to the third generation data 
base) were in response to public comments received to May 1997 NODA.
---------------------------------------------------------------------------

    \25\ USEPA, ``Draft Technical Support Document for HWC MACT 
Standards, Volume II: HWC Emissions Database,'' February 1996.
    \26\ See USEPA, ``Draft Report of Revisions to Hazardous Waste 
Combustor Database Based on Public Comments Submitted in Response to 
the January 7, 1997 Notice of Data Availability (NODA),'' May 1997.
---------------------------------------------------------------------------

B. How Are Data Quality and Data Handling Issues Addressed?
    We selected approaches to resolve several data quality and handling 
issues regarding: (1) Data from sources no longer burning hazardous 
waste; (2) assigning values to reported nondetect measurements; (3) 
data generated under normal conditions versus worst-case compliance 
conditions; and (4) use of imputation techniques to fill in missing or 
unavailable data. This section discusses our selected approaches to 
these four issues.

[[Page 52844]]

1. How Are Data From Sources No Longer Burning Hazardous Waste Handled?
    Data and information from sources no longer burning hazardous waste 
are not considered in the MACT standards evaluations promulgated today. 
We note that some facilities have recently announced plans to cease 
burning hazardous waste. Because we cannot continually adjust our data 
base and still finalize this rulemaking, we concluded revisions to the 
data base in early 1998. Announcements or actual facility changes after 
that date simply could not be incorporated.
    Numerous commenters responded to our request for comment on the 
appropriate approach to handle emissions data from sources no longer 
burning hazardous waste. In the April 1996 proposal, we considered all 
available data, including data from sources that had since ceased waste 
burning operations. However, in response to comments to the April 1996 
NPRM, in the May 1997 NODA we excluded data from sources no longer 
burning hazardous waste and reevaluated the MACT floors with the 
revised data base. Of the data included in the fourth generation data 
base, the number of sources that have ceased waste burning operations 
include 18 incineration facilities comprising 18 sources; eight cement 
kiln facilities comprising 12 sources; and one lightweight aggregate 
kiln facility comprising one source.
    Several commenters support the inclusion in the MACT analyses of 
data from sources no longer burning hazardous waste. They believe the 
performance data from these sources are representative of emissions 
control achievable when burning hazardous waste because the data were 
generated under compliance testing conditions. Other commenters suggest 
that data from sources no longer burning hazardous waste should be 
excluded from consideration when conducting MACT floor analyses to 
ensure that the identified MACT floor levels are achievable.
    The approach we adopt today is identical to the one we used for the 
May 1997 NODA. Rather than becoming embroiled in a controversy over 
continued achievability of the MACT standards, we exercise our 
discretion and use a data base consisting of only facilities now 
operating (at least as of the data base finalization date). Ample data 
exist to support setting the MACT standards without using data from 
facilities that no longer burn hazardous waste. To the extent that some 
previous data from facilities not now burning hazardous waste still 
remain in the data base, we ascribe to the view that these data are 
representative of achievable emissions control and can be used.
2. How Are Nondetect Data Handled?
    In today's rule, as in the May 1997 NODA, we evaluated nondetect 
values, extracted from compliance test reports and typically associated 
with feedstream input measurements rather than emissions 
concentrations, as concentrations that are present at one-half the 
detection limit. In the proposal, we assumed that nondetect analyses 
were present at the value of the full detection limit.
    Some commenters support our approach to assume that nondetect 
values are present at one-half the detection limit. The commenter 
states that this approach is consistent with the data analysis 
techniques used in other EPA environmental programs such as in the 
evaluation of groundwater monitoring data. Other commenters oppose 
treating nondetect values at one-half the detection limit, especially 
for dioxins/furans because Method 23 for quantitating stack emissions 
states that nondetect values for congeners be treated as zero when 
calculating total congeners and the toxicity equivalence quotient for 
dioxins/furans. As explained in the NODA, the assumption that nondetect 
measurements are present at one-half the reported detection limit is 
more technically and environmentally conservative and increases our 
confidence that standards and risk findings are appropriate. Further, 
we considered assuming that nondetect values were present at the full 
detection limit, but found that there were no significant differences 
in the MACT data analysis results.27 Therefore, in today's 
rule, we assume nondetect measurements are present at one-half the 
detection limit.
---------------------------------------------------------------------------

    \27\ Using dioxins and furans as an example, for those sources 
using MACT control, this difference is no more than approximately 10 
percent of the standard. USEPA, ``Final Technical Support Document 
for HWC MACT Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

3. How Are Normal Versus Worst-Case Emissions Data Handled?
    The majority of the available emissions data for all of the 
hazardous air pollutants except mercury can be considered worst-case 
because they were generated during RCRA compliance testing. Because 
limits on operating parameters are established based on compliance test 
operations, sources generally operate during compliance testing under 
worst-case conditions to account for variability in operations and 
emissions. However, the data base also contains some normal data for 
these hazardous air pollutants. Normal data include those where 
hazardous waste was burned, but neither spiking of the hazardous waste 
with metals or chlorine nor operation of the combustion unit and 
emission control equipment under detuned conditions occurred.
    In the MACT analyses supporting today's rule, normal data were not 
used to identify or define MACT floor control, with the exception of 
mercury, as discussed below. This approach is identical to the one used 
in the May 1997 NODA. 62 FR 24216.
    Several commenters support the use of normal emissions data in 
defining MACT controls because the effect of ignoring the potentially 
lower emitters from these sources would skew the analysis to higher 
floor results. Other commenters oppose the use of normal data because 
they would not be representative of emissions under compliance test 
conditions--the conditions these same sources will need to operate 
under during MACT performance tests to establish limits on operating 
conditions.28
---------------------------------------------------------------------------

    \28\ These commenters are concerned that, if the standards were 
based on normal emissions data, sources would be inappropriately 
constrained to emissions that are well below what is currently 
normal. This is because of the double ratcheting effect of the 
compliance regime whereby a source must first operate below the 
standard during compliance testing, and then again operate below 
compliance testing levels (and associated operating parameters) to 
maintain day-to-day compliance.
---------------------------------------------------------------------------

    We conclude that it is inappropriate to perform the MACT floor 
analysis for a particular hazardous air pollutant using emissions data 
that are a mixture of normal and worst-case data. The few normal 
emissions data would tend to dominate the identification of best 
performing sources while not necessarily being representative of the 
range of normal emissions. Because the vast majority of our data is 
based on worst-case compliance testing, the definition of floor control 
is based on worst-case data.29 Using worst-case emissions 
data to establish a MACT

[[Page 52845]]

floor also helps account for emissions variability, as discussed in 
Section V.D. below.
---------------------------------------------------------------------------

    \29\ We considered adjusting the emissions data to account for 
spiking to develop a projected normal emissions data base. However, 
we conclude that this is problematic and have not done so. For 
example, it is difficult to project (lower) emissions from 
semivolatile metal-spiked emissions data given that system removal 
efficiency does not correlate linearly with semivolatile metal 
feedrate. In addition, we did not know for certain whether some data 
were spiked. Thus, we would have to use either a truncated data base 
of despiked data or a mixed data base of potentially spiked data and 
despiked data, neither of which would be fully satisfactory.
---------------------------------------------------------------------------

    Sources did not generally spike mercury emissions during RCRA 
compliance testing because they normally feed mercury at levels 
resulting in emissions well below current limits.30 
Consequently, sources are generally complying with generic, 
conservative feedrate limits established under RCRA rather than 
feedrate limits established during compliance testing. Because our data 
base is comprised essentially of normal emissions, we believe this is 
one instance where use of normal data to identify MACT floor is 
appropriate. See discussion in Section V.D. below of how emissions 
variability is addressed for the mercury floors.
---------------------------------------------------------------------------

    \30\ Three of 23 incinerators used to define MACT floor (i.e., 
sources for which mercury feedrate data are available) are known to 
have spiked mercury. No cement kilns used to define MACT floor 
(e.g., excluding sources that have stopped burning hazardous waste) 
are known to have spiked mercury. Only one of ten lightweight 
aggregate kilns used to define MACT floor is known to have spiked 
mercury.
---------------------------------------------------------------------------

4. What Approach Was Used To Fill In Missing or Unavailable Data?
    With respect to today's rule, the term ``imputation'' refers to a 
data handling technique where a value is filled-in for a missing or 
unavailable data point. We only applied this technique to hazardous air 
pollutants that are comprised of more than one pollutant (i.e., 
semivolatile metals, low volatile metals, total chlorine). We used 
imputation techniques in both the proposal and May 1997 NODA; however, 
we decided not to use imputation procedures in the development of 
today's promulgated standards. We used only complete data sets in our 
MACT determinations. Several commenters to the proposal and May 1997 
NODA oppose the use of imputation techniques. Commenters express 
concern that the imputation approach used in the proposal did not 
preserve the statistical characteristics (average and standard 
deviation) of the entire data set. Thus, commenters suggest that 
subsequent MACT analyses were flawed. We reevaluated the data base and 
determined that a sufficient number of data sets are complete without 
the use of an imputation technique.31 A complete discussion 
of various data handling conventions is presented in the technical 
support document.32
---------------------------------------------------------------------------

    \31\ This is especially true because antimony is no longer 
included in the low volatile metal standard.
    \32\ See USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

II. How Did We Select the Pollutants Regulated by This Rule?

    Section 112(b) of the Clean Air Act, as amended, provides a list of 
188 33 hazardous air pollutants for which the Administrator 
must promulgate emission standards for designated major and area 
sources. The list is comprised of metal, organic, and inorganic 
compounds.
---------------------------------------------------------------------------

    \33\ The initial list consisted of 189 HAPs, but we have removed 
caprolactam (CAS number 105602) from the list of hazardous air 
pollutants. See Sec. 63.60.
---------------------------------------------------------------------------

    Hazardous waste combustors emit many of the hazardous air 
pollutants. In particular, hazardous waste combustors can emit high 
levels of dioxins and furans, mercury, lead, chromium, antimony, and 
hydrogen chloride. In addition, hazardous waste combustors can emit a 
wide range of nondioxin/furan organic hazardous air pollutants, 
including benzene, chloroform, and methylene chloride.
    In today's rule, we establish nine emission standards to control 
hazardous air pollutants emitted by hazardous waste combustors. 
Specifically, we establish emission standards for the following 
hazardous air pollutants: Chlorinated dioxins and furans, mercury, two 
semivolatile metals (i.e., lead and cadmium), three low volatility 
metals (i.e., arsenic, beryllium, chromium), and hydrochloric acid/
chlorine gas. In addition, MACT control is provided for other hazardous 
air pollutants via standards for surrogates: (1) A standard for 
particulate matter will control five metal hazardous air pollutants--
antimony, cobalt, manganese, nickel, and selenium; and (2) standards 
for carbon monoxide, hydrocarbons, and destruction and removal 
efficiency will control nondioxin/furan organic hazardous air 
pollutants.
A. Which Toxic Metals Are Regulated by This Rule? 34
---------------------------------------------------------------------------

    \34\ RCRA standards currently control emissions of three toxic 
metals that have not been designated as Clean Air Act hazardous air 
pollutants: Barium, silver, and thallium. These RCRA metals are 
incidentally controlled by today's MACT controls for metal hazardous 
air pollutants in two ways. First, the RCRA metals are semivolatile 
or nonvolatile and will, in part, be controlled by the air pollution 
control systems used to meet the semivolatile metal and low volatile 
metal standards in today's rule. Second, these RCRA metals will be 
controlled by the measures used to meet today's MACT participate 
matter standard. See text that follows.
---------------------------------------------------------------------------

1. Semivolatile and Low Volatile Metals
    The Section 112(b) list of hazardous air pollutants includes 11 
metals: antimony, arsenic, beryllium, cadmium, chromium, cobalt, lead, 
manganese, mercury, nickel, and selenium. To establish an implementable 
approach for controlling these metal hazardous air pollutants, we 
proposed to group the metals by their relative volatility and 
established emission standards for each volatility group. We placed six 
of the eleven metals in volatility groups. The high-volatile group is 
comprised of mercury, the semivolatile group is comprised of lead and 
cadmium, and the low volatile group is comprised of arsenic, beryllium, 
and chromium.35 We refer to these six metals for which we 
have established standards based on volatility group as ``enumerated 
metals.'' We have chosen to control the remaining five metals using 
particulate matter as a surrogate as discussed in the next section.
---------------------------------------------------------------------------

    \35\ Antimony was included in the low volatile group at 
proposal, but we subsequently determined that the MACT particulate 
matter standard serves as an adequate surrogate for this metal. See 
the May 1997 NODA (62 FR at 24216). In making this determination, we 
noted that antimony is an noncarcinogen with relatively low toxicity 
compared with the other five nonmercury metals that were placed in 
volatility groups. To be of particular concern, antimony would have 
to be present in hazardous waste at several orders of magnitude 
higher than shown in the available data.
---------------------------------------------------------------------------

    Grouping metals by volatility is reasonable given that emission 
control strategies are governed primarily by a metal's volatility. For 
example, while semivolatile metals and low volatile metals are in 
particulate form in the emission control train and can be removed as 
particulate matter, mercury species are generally emitted from 
hazardous waste combustors in the vapor phase and cannot be controlled 
by controlling particulate matter unless a sorbent, such as activated 
carbon, is injected into the combustion gas. In addition, low volatile 
metals are easier to control than semivolatile metals because 
semivolatile metals volatilize in the combustion chamber and condense 
on fine particulate matter, which is somewhat more difficult to 
control. Low volatile metals do not volatilize significantly in 
hazardous waste combustors and are emitted as larger, easier to remove, 
particles entrained in the combustion gas.36
---------------------------------------------------------------------------

    \36\ The dynamics associated with the fate of metals in a 
hazardous waste combustor are much more complex than presented here. 
For more information, see USEPA, ``Draft Technical Support Document 
for HWC MACT Standards, Volume VII: Miscellaneous Technical 
Issues,'' February 1996.
---------------------------------------------------------------------------

    Commenters agree with our proposal to group metals by their 
relative volatility. We adopt these groupings for the final rule.
    We note that the final rule does not require a source to control 
its particulate matter below the particulate matter standard to control 
semivolatile and low

[[Page 52846]]

volatile metals. It is true that when we were determining the 
semivolatile and low volatile metal floor standards, we did examine the 
feedrates from only those facilities that were meeting the numerical 
particulate standard. See Part Four, Section V.B.2.c. This is because 
we believe that facilities, in practice, use both feedrate and 
particulate matter air pollution control devices in a complementary 
manner to address metals emissions (except mercury). However, our 
setting of the semivolatile and low volatile metal floor standards does 
not require MACT particulate matter control to be installed, either 
directly or indirectly, as a matter of CAA compliance. We do not think 
it is necessary to require compliance with a particulate matter 
standard as an additional express element of the semivolatile/low 
volatile metal emission standards because the particulate matter 
standard is already required to control the nonenumerated metals, as 
discussed below. However, we could have required compliance with a 
particulate matter standard as part of the semivolatile or low volatile 
metal emission standard because of the practice of using particulate 
matter control as at least part of a facility's strategy to control or 
minimize metal emissions (other than mercury).
2. How Are the Five Other Metal Hazardous Air Pollutants Regulated?
    We did not include five metal hazardous air pollutants (i.e., 
antimony, cobalt, manganese, nickel, selenium) in the volatility groups 
because of: (1) Inadequate emissions data for these metals 
37; (2) relatively low toxicity of antimony, cobalt, and 
manganese; and (3) the ability to achieve control, as explained below, 
by means of surrogates. Instead, we chose the particulate matter 
standard as a surrogate control for antimony, cobalt, manganese, 
nickel, and selenium. We refer to these five metals as ``nonenumerated 
metals'' because standards specific to each metal have not been 
established. We conclude that emissions of these metals is effectively 
controlled by the same air pollution control devices and systems used 
to control particulate matter.
---------------------------------------------------------------------------

    \37\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume II: HWC Emissions Database,'' July 1999.
---------------------------------------------------------------------------

    Some commenters suggest that particulate matter is not a surrogate 
for the five nonenumerated metals. Commenters also note that our own 
study, as well as investigations by commenters, did not show a 
relationship between particulate matter and semivolatile metals and low 
volatile metals when emissions from multiple sources were considered. 
However, we conclude that such a relationship is not expected when 
multiple sources are considered because wide variations in source 
operations can affect: (1) Metals and particulate matter loadings at 
the inlet to the particulate matter control device; (2) metals and 
particulate matter collection efficiency; and (3) metals and 
particulate matter emissions. Factors that can contribute to 
variability in source operations include metal feed rates, ash levels, 
waste types and physical properties (i.e., liquid vs. solid), 
combustion temperatures, and particulate matter device design, 
operation, and maintenance.
    Conversely, emissions of semivolatile metals and low volatile 
metals are directly related to emissions of particulate matter at a 
given source when other operating conditions are held constant (i.e., 
as particulate matter emissions increase, emissions of these metals 
also increase) because semivolatile metals and low volatile metals are 
present as particulate matter at the typical air pollution control 
device temperatures of 200 to 400 deg.F that are required under today's 
rule.38 A strong relationship between particulate matter and 
semivolatile/low volatile metal emissions is evident from our emissions 
data base of trial burn emissions at individual sources where 
particulate matter varies and metals feedrates and other conditions 
that may affect metals emissions were held fairly constant. Other work 
also has clearly demonstrated that improvement in particulate control 
leads to improved metals control.39
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    \38\ The dioxin/furan emission standard requires that gas 
temperatures at the inlet to electrostatic precipitators and fabric 
filters not exceed 400 deg.F. Wet particulate matter control devices 
reduce gas temperatures to below 400 deg.F by virtue of their design 
and operation. The vapor phase contribution (i.e., nonparticulate 
form that will not be controlled by a particulate matter control 
device) of semivolatile metal and low volatile metal at these 
temperatures is negligible.
    \39\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    We also requested comment on whether particulate matter could be 
used as a surrogate for all semivolatile and low volatile metal 
hazardous air pollutants (i.e., all metal hazardous air pollutants 
except mercury). See the May 1997 NODA. This approach is strongly 
recommended by the cement industry. In that Notice, we concluded that, 
because of varying and high levels of metals concentrations in 
hazardous waste, use of particulate matter control alone may not 
provide MACT control for metal hazardous air pollutants.40 
Our conclusion is the same today. Without metal-specific MACT emission 
standards or MACT feedrate standards, sources could feed high levels of 
one or more metal hazardous air pollutant metals. This practice could 
result in high metal emissions, even though the source's particulate 
matter is controlled to the emission standard (i.e., a large fraction 
of emitted particulate matter could be comprised of metal hazardous air 
pollutants). Thus, the use of particulate matter control alone would 
not constitute MACT control of that metal and would be particularly 
troublesome for the enumerated semivolatile and low volatile metal 
because of their toxicity.41
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    \40\ However, for sources not burning hazardous waste and 
without a significant potential for extreme variability in metals 
feedrates, particulate matter is an adequate surrogate for metal 
hazardous air pollutants (e.g., for nonhazardous waste burning 
cement kilns).
    \41\ Using particulate matter as a surrogate for metals is, 
however, the approach we used in the final rule for five metals: 
Antimony, cobalt, manganese, nickel, selenium. Technical and 
practical reasons unique to these metals support this approach. 
First, these metals exhibit relatively low toxicity. Second, for 
some of these metals, we did not have emissions data adequate to 
establish specific standards. Therefore, the best strategy for these 
particular metals, at this time, is to rely on particulate matter as 
a surrogate.
---------------------------------------------------------------------------

    Many commenters suggest that particulate matter is an adequate 
surrogate for all metal hazardous air pollutants. They suggest that, 
given current metal feedrates and emission rates, particularly in the 
cement industry, a particulate matter standard is sufficient to ensure 
that metal hazardous air pollutants (other than mercury) are controlled 
to levels that would not pose a risk to human health or the 
environment. While this may be true in some cases as a theoretical 
matter, it may not be in all cases. Data demonstrating this 
conclusively were not available for all cement kilns. Moreover, this 
approach may not ensure MACT control of the potentially problematic 
(i.e., high potential risk) metals for reasons discussed above (i.e., 
higher metal feedrates will result in higher metals emissions even 
though particulate matter capture efficiency remains constant). 
Consequently, we conclude that semi-volatile metals and low volatile 
metals standards are appropriate in addition to the particulate matter 
standard.
    Finally, several commenters suggest that a particulate matter 
standard is not needed to control the five nonenumerated metals because 
the standards for the enumerated semivolatile and low volatile metals 
would serve as surrogates for those

[[Page 52847]]

metals. Their rationale is that because the nonenumerated metals can be 
classified as either semivolatile or nonvolatile 42, they 
would be controlled along with the enumerated semivolatile and low 
volatile metals. However, MACT control would not be assured for the 
five nonenumerated metals even though they would be controlled by the 
same emission control device as the enumerated semivolatile and low 
volatile metals. For example, a source with high particulate matter 
emissions could achieve the semivolatile and low volatile metal 
emission standards (i.e., MACT control) by feeding low levels of 
enumerated semivolatile and low volatile metals. But, if that source 
also fed high levels of nonenumerated metals, MACT control for those 
metals would not be achieved unless the source was subject to a 
particulate matter MACT standard. Consequently, we do not agree that 
the semivolatile and low volatile metal standards alone can serve as 
surrogates for the nonenumerated metals.
---------------------------------------------------------------------------

    \42\ As a factual matter, selenium can be classified as a 
semivolatile metal and the remaining four nonenumerated metals can 
be classified as low volatile metals.
---------------------------------------------------------------------------

    We also proposed to use particulate matter as a supplemental 
control for nondioxin/furan organic hazardous air pollutants that are 
adsorbed onto the particulate matter. Commenters state, however, that 
the Agency had not presented data showing that particulate matter in 
fact contains significant levels of adsorbed nondioxin/furan organic 
hazardous air pollutants. We now concur with commenters that, for 
cement kiln and lightweight aggregate kiln particulate matter, 
particulate matter emissions have not been shown to contain significant 
levels of adsorbed organic compounds. This is likely because cement 
kiln and lightweight aggregate kiln particulate matter is primarily 
inert process dust (i.e., entrained raw material). Although particulate 
matter emissions from incinerators could contain higher levels of 
carbon that may adsorb some organic compounds, this is not likely a 
significant means of control for those organic hazardous air 
pollutants.43
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    \43\ We recognize that sorbent (e.g., activated carbon) may be 
injected into the combustion system to control mercury or dioxin/
furan. In these cases, particulate matter would be controlled as a 
site-specific compliance parameter for these organics. See the 
discussion in Part Five of this preamble.
---------------------------------------------------------------------------

B. How Are Toxic Organic Compounds Regulated by This Rule?
1. Dioxins/Furans
    We proposed that dioxin/furan emissions be controlled directly with 
a dioxin/furan emission standard based on toxicity equivalents. The 
final rule adopts a TEQ approach for dioxin/furans. In terms of a 
source determining compliance, we expect sources to use accepted TEQ 
references.44
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    \44\ For example, USEPA, ``Interim Procedure for Estimating 
Risks Associated With Exposures to Mixtures of Chlorinated Dibenzo-
p-Dioxin and -Dibenzofurans (CDDs and CDFs) and 1989 Update'', March 
1989; Van den Berg, M., et al. ``Toxic Equivalency Factors (TEFs) 
for PCBs, PCDDs, PCDFs for Humans and Wildlife'' Environmental 
Health Perspectives, Volume 106, Number 12, December 1998.
---------------------------------------------------------------------------

2. Carbon Monoxide and Hydrocarbons
    We proposed that emissions of nondioxin/furan organic hazardous air 
pollutants be controlled by compliance with continuously monitored 
emission standards for either of two surrogates: carbon monoxide or 
hydrocarbons. Carbon monoxide and hydrocarbons are widely accepted 
indicators of combustion conditions. The current RCRA regulations for 
hazardous waste combustors use emissions limits on carbon monoxide and 
hydrocarbons to control emissions of nondioxin/furan toxic organic 
emissions. See 56 FR 7150 (February 21, 1991) documenting the 
relationship between carbon monoxide, combustion efficiency, and 
emissions of organic compounds. In addition, Clean Air Act emission 
standards for municipal waste combustors and medical waste incinerators 
limit emissions of carbon monoxide to control nondioxin/furan organic 
hazardous air pollutants. Finally, hydrocarbon emissions are an 
indicator of organic hazardous air pollutants because hydrocarbons are 
a direct measure of organic compounds.
    Nonetheless, many commenters state that EPA's own surrogate 
evaluation 45 did not demonstrate a relationship between 
carbon monoxide or hydrocarbons and nondioxin/furan organic hazardous 
air pollutants at the carbon monoxide and hydrocarbon levels evaluated. 
Several commenters note that this should not have been a surprise given 
that the carbon monoxide and hydrocarbon emissions data evaluated were 
generally from hazardous waste combustors operating under good 
combustion conditions (and thus, relatively low carbon monoxide and 
hydrocarbon levels). Under these conditions, emissions of nondioxin/
furan organic hazardous air pollutants were generally low, which made 
the demonstration of a relationship more difficult. These commenters 
note that there may be a correlation between carbon monoxide and 
hydrocarbons and nondioxin/furan organic hazardous air pollutants, but 
it would be evident primarily when actual carbon monoxide and 
hydrocarbon levels are higher than the regulatory levels. We agree, and 
conclude that carbon monoxide and hydrocarbon levels higher than those 
we establish as emission standards are indicative of poor combustion 
conditions and the potential for increased emissions of nondioxin/furan 
organic hazardous air pollutants. Consequently, we have adopted our 
proposed approach for today's final rule.46
---------------------------------------------------------------------------

    \45\ See Energy and Environmental Research Corporation, 
``Surrogate Evaluation of Thermal Treatment Systems,'' Draft Report, 
October 17, 1994.
    \46\ As discussed at proposal, however, this relationship does 
not hold for certain types of cement kilns where carbon monoxide and 
hydrocarbons emissions evolve from raw materials. See discussion in 
Section VII of Part Four.
---------------------------------------------------------------------------

3. Destruction and Removal Efficiency
    We have determined that a destruction and removal efficiency (DRE) 
standard is needed to ensure MACT control of nondioxin/furan organic 
hazardous air pollutants.47 We adopt the implementation 
procedures from the current RCRA requirements for DRE (see 
Secs. 264.342, 264.343, and 266.104) in today's final rule. The 
rationale for adopting destruction and removal efficiency as a MACT 
standard is discussed later in Section IV of the preamble.
---------------------------------------------------------------------------

    \47\ Under this standard, several difficult to combust organic 
compounds would be identified and destroyed or removed by the 
combustor to at least a 99.99% (or 99.9999%, as applicable) 
efficiency.
---------------------------------------------------------------------------

C. How Are Hydrochloric Acid and Chlorine Gas Regulated by This Rule?
    We proposed that hydrochloric acid and chlorine gas emissions be 
controlled by a combined total chlorine MACT standard because: (1) The 
test method used to determine hydrochloric acid and chlorine gas 
emissions may not be able to distinguish between the compounds in all 
situations; 48 and (2) both of these hazardous air 
pollutants can be controlled by limiting feedrate of chlorine in 
hazardous waste and wet scrubbing. We have adopted this approach in 
today's final rule.
---------------------------------------------------------------------------

    \48\ See the proposed rule, 61 FR at 17376.
---------------------------------------------------------------------------

    One commenter questions whether it is appropriate to establish a 
combined standard for hydrochloric acid and chlorine gas because the 
removal efficiency of emission control equipment is substantially 
different for the two pollutants. Although we agree that the efficiency 
of emission control equipment is substantially different for the two 
pollutants, we conclude that the MACT control techniques will readily

[[Page 52848]]

enable sources to achieve the hydrochloric acid/chlorine gas emission 
standard. As discussed in Sections VI, VII, and VIII below, MACT 
control for all hazardous waste combustors is control of the hazardous 
waste chlorine feedrate. This control technique is equally effective 
for hydrochloric acid and chlorine gas and represents MACT control for 
cement kilns. MACT control for incinerators also includes wet 
scrubbing. Although wet scrubbing is more efficient for controlling 
hydrochloric acid, it also provides some control of chlorine gas. MACT 
control for lightweight aggregate kilns also includes wet or dry 
scrubbing. Although dry scrubbing does not control chlorine gas, 
chlorine feedrate control combined with dry scrubbing to remove 
hydrochloric acid will enable lightweight aggregate kilns to achieve 
the emission standard for hydrochloric acid/chlorine gas.

III. How Are the Standards Formatted in This Rule?

A. What Are the Units of the Standards?
    With one exception, the final rule expresses the emission standards 
on a concentration basis as proposed, with all standards expressed as 
mass per dry standard cubic meter (e.g., g/dscm), with 
hydrochloric acid/chlorine gas, carbon monoxide, and hydrocarbon 
standards being expressed at parts per million by volume (ppmv). The 
exception is the particulate matter standard for hazardous waste 
burning cement kilns where the standard is expressed as kilograms of 
particulate matter per Mg of dry feed to the kiln.
    Several commenters suggest that the standards should be expressed 
on a mass emission basis (e.g., mg/hour) because of equity concerns 
across source categories and environmental loading concerns. They are 
concerned that expressing the standards on a concentration basis allows 
large gas flow rate sources such as cement kilns to emit a much greater 
mass of hazardous air pollutants per unit time than smaller sources 
such as some on-site incinerators. Concomitantly, small sources would 
incur a higher cost/lb of pollutant removed, they contend, than a large 
source.49 Further, they reason that the larger sources would 
pose a much greater risk to human health and the environment because 
risk is a function of mass emissions of pollutants per unit of time.
---------------------------------------------------------------------------

    \49\ This result is not evident given that the cost of an 
emission control device is generally directly proportional to the 
gas flow rate, not the mass emission rate of pollutants per unit 
time.
---------------------------------------------------------------------------

    Although we agree with commenters' point about differential 
environmental loadings attributable to small versus large sources with 
a concentration-based standard, we note that the mass-based standard 
urged here is inherently incompatible with technology-based MACT 
standards for several reasons.50 A mass-based standard does 
not ensure MACT control at small sources. Small sources have lower flow 
rates and thus would be allowed to emit hazardous air pollutants at 
high concentrations. They could meet the standard with no or minimal 
control. In addition, this inequity between small and large sources 
would create an incentive to divert hazardous waste from large sources 
to small sources (existing and new), causing an increase in emissions 
nationally.
---------------------------------------------------------------------------

    \50\ Although the particulate matter standard for hazardous 
waste burning cement kilns in today's rule is the New Source 
Performance Standard expressed as on a mass basis (i.e., kg of 
particulate matter per megagram of dry feed to the kiln), this 
standard is not based on a ``mass of particulate matter emissions 
per unit of time'' that commenters suggest. Rather, the cement kiln 
standard can be equated to a concentration basis given that cement 
kilns emit a given quantity of combustion gas per unit of dry feed 
to the kiln. In fact, we proposed the cement kiln particulate matter 
standard on a concentration basis, 0.03 gr/dscf, that was calculated 
from the New Source Performance Standard when applied to a typical 
wet process cement kiln.
---------------------------------------------------------------------------

B. Why Are the Standards Corrected for Oxygen and Temperature?
    As proposed, the final standards are corrected to 7 percent oxygen 
and 20 deg.C because the data we use to establish the standards are 
corrected in this manner and because the current RCRA regulations for 
these sources require this correction. These corrections normalize the 
emissions data to a common base, recognizing the variation among the 
different combustors and modes of operation.
    Several commenters note that the proposed oxygen correction 
equation does not appropriately address hazardous waste combustors that 
use oxygen enrichment systems. They recommend that the Agency 
promulgate the oxygen correction factor equation proposed in 1990 for 
RCRA hazardous waste incinerators. See 55 FR at 17918 (April 27, 1990). 
We concur, and adopt the revised oxygen correction factor equation.
C. How Does the Rule Treat Significant Figures and Rounding?
    As proposed, the final rule establishes standards and limits based 
on two significant figures. One commenter notes that a minimum of three 
significant figures must be used for all intermediate calculations when 
rounding the results to two significant figures. We concur. Sources 
should use standard procedures, such as ASTM procedure E-29-90, to 
round final emission levels to two significant figures.

IV. How Are Nondioxin/Furan Organic Hazardous Air Pollutants 
Controlled?

    Nondioxin/furan organic hazardous air pollutants are controlled by 
a destruction and removal efficiency (DRE) standard and the carbon 
monoxide and hydrocarbon standards. Previous DRE tests demonstrating 
compliance with the 99.99% requirement under current RCRA regulations 
may be used to document compliance with the DRE standard provided that 
operations have not been changed in a way that could reasonably be 
expected to affect ability to meet the standard. However, if waste is 
fed at a point other than the flame zone, then compliance with the 
99.99% DRE standard must be demonstrated during each comprehensive 
performance test, and new operating parameter limits must be 
established to ensure that DRE is maintained. A 99.9999% DRE is 
required for those hazardous waste combustors burning dioxin-listed 
wastes. These requirements are discussed in Section IV.A. below.
    In addition, the rule establishes carbon monoxide and hydrocarbons 
emission standards as surrogates to ensure good combustion and control 
of nondioxin/furan organic hazardous air pollutants. Continuous 
monitoring and compliance with either the carbon monoxide or 
hydrocarbon emissions standard is required. If you choose to 
continuously monitor and comply with the carbon monoxide standard, you 
must also demonstrate during the comprehensive performance test 
compliance with the hydrocarbon emission standard. Additionally, you 
must also set operating limits on key parameters that affect combustion 
conditions to ensure continued compliance with the hydrocarbon emission 
standard. Alternatively, continuous monitoring and compliance with the 
hydrocarbon emissions standard eliminates the need to monitor carbon 
monoxide emissions because hydrocarbon emissions are a more direct 
surrogate of nondioxin/furan organic hazardous air pollutant emissions. 
These requirements are discussed in Section IV.B below.
A. What Is the Rationale for DRE as a MACT Standard?
    All sources must demonstrate the ability to destroy or remove 99.99

[[Page 52849]]

percent of selected principal organic hazardous compounds in the waste 
feed as a MACT standard. This requirement, commonly referred to as 
four-nines DRE, is a current RCRA requirement. We are promulgating the 
DRE requirement as a MACT floor standard to control the emissions of 
nondioxin organic hazardous air pollutants. The rule also requires 
sources to establish limits on specified operating parameters to ensure 
compliance with the DRE standard. See Part Five Section VII(B).
    In the April 1996 NPRM, we proposed that the four-nines DRE test 
requirement be retained under RCRA and be performed as part of a RCRA 
approved trial burn because we did not believe that the DRE test could 
be adequately implemented using the generally self-implementing MACT 
performance test and notification process.51 See 61 FR 
17447.
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    \51\ Historically, under RCRA regulations, the permittiing 
authority and hazardous waste combustion source found it necessary 
to go through lengthy negotiations to develop a RCRA trial burn plan 
that adequately demonstrates the unit's ability to achieve four-
nines DRE.
---------------------------------------------------------------------------

    In response to the April proposal, however, we received comments 
that suggest the MACT comprehensive performance test and RCRA DRE trial 
burn could and should be combined, and that we should combine all stack 
air emission requirements for hazardous waste combustors into a single 
permit. Commenters are concerned that our proposed approach required 
sources to obtain two permits for air emissions and potentially be 
unnecessarily subject to dual enforcement.
    We investigated approaches that would achieve the goals of a single 
air emission permit and inclusion of DRE in MACT. We determined that 
the 40 CFR part 63 general provisions, applicable to all MACT regulated 
sources unless superseded, includes a process similar to the process to 
develop a RCRA trial burn test plan and allows permitting authorities 
to review and approve MACT performance test plans. See 40 CFR 63.7. 
Additionally, we determined that, because all hazardous waste 
combustors are currently required to achieve four-nines DRE, the DRE 
requirement could be included as a MACT floor standard rather than a 
RCRA requirement. In the May 1997 NODA, we discussed an alternative 
approach that used a modified form of the general provision's 
performance test plan and approval process. The approach would allow 
combination of the DRE test with the comprehensive performance test 
and, therefore, facilitate implementation of DRE as a MACT standard. We 
also discussed modifying the general approach to extend the performance 
test plan review period to one year in advance of the date a source 
plans to perform the comprehensive performance test. This extended 
review period would provide sufficient time for negotiations between 
permitting authorities and sources to develop and approve comprehensive 
performance test plans. These test plans would identify operating 
parameter limits necessary to ensure compliance with all the proposed 
MACT standards, as well as, implement the four-nines DRE test as a MACT 
floor standard. See 62 FR at 24241. Commenters support the process to 
combine the applicable stack emission requirements into a single 
permit. As for making the DRE test a MACT standard, we received no 
negative comments. Many commenters, however, question the need for 
subsequent DRE testing once a unit demonstrates four-nines DRE. See 
discussion and our response in Subsection 2 below.
    We believe that requiring the DRE test as a MACT standard is 
appropriate. As we previously noted, the four-nines DRE is firmly 
grounded statutory and regulatory requirement that has proven to be an 
effective method to determine appropriate process controls necessary 
for the combustion of hazardous waste. Specifically, RCRA requires that 
all hazardous waste incinerators must demonstrate the minimum 
technology requirement of four-nines DRE (RCRA section 3004(o)(1)(B)). 
Additionally, the current RCRA BIF regulations require that all boiler 
and industrial furnaces meet the four-nines DRE standard. Moreover, 
current RCRA regulations require all sources incinerating certain 
dioxin-listed contaminated wastes (F020-023 and F026-27) to achieve 
99.9999% (six-nines) DRE. See Secs. 264.343(a)(2) and 266.104(a)(3).
    The statutory requirement for incinerators to meet four-nines DRE 
can be satisfied if the associated MACT requirements ensure that 
incinerators will continue to meet the four-nines DRE minimum 
technology requirement, i.e., that MACT standards provide at least the 
``minimum'' RCRA section 3004(o)(1) level of control. To determine if 
the RCRA statutory requirements could be satisfied, we investigated 
whether DRE could be replaced with universal standards for key 
operating parameters based on previous DRE demonstrations (i.e., 
standards for carbon monoxide and hydrocarbon emissions). We found 
that, in the vast majority of DRE test conditions, if a unit operated 
with carbon monoxide levels of less than 100 ppmv and hydrocarbon 
emissions of less than 10 ppmv, the unit met or surpassed four-nines 
DRE. In a small number of test conditions, units emitted carbon 
monoxide and hydrocarbons at levels less than 100 and 10 ppmv 
respectively, but failed to meet four-nines DRE. Most failed test 
conditions were either due to questionable test results or faulty test 
design.52 See U.S. EPA, ``Draft Technical Support Document 
for HWC MACT Standards (NODA), Volume II: Evaluation of CO/HC and DRE 
Database,'' April 1997. Even though we could potentially explain the 
reasons these units failed to achieve four-nines DRE, we determined 
that universal carbon monoxide and hydrocarbon emissions limits may not 
ensure that all units achieve four-nines DRE because carbon monoxide 
and hydrocarbon emissions may not be representative of good combustion 
for all operating conditions that facilities may desire to operate. In 
addition, we could not identify a better method than the DRE test to 
limit combustion failures modes.
---------------------------------------------------------------------------

    \52\ In many of the failed test conditions that we investigated, 
the facility fed a low concentration of organic compound on which 
the DRE was being calculated. As has been observed many times, 
organic compounds can be reformed in the post combustion gas stream 
at concentrations sufficient to fail DRE. This is not indicative of 
a failure in the systems ability to destroy the compound, but is 
more likely the result of a poorly designed test. If the facility 
had fed a higher concentration of organic compound in the waste to 
the combustor, the unit would have been more likely to meet four-
nines DRE with no change in the operating conditions used during the 
test. In other cases, poor test design (i.e., firing aqueous organic 
waste into an unfired secondary combustion chamber) is considered to 
be the cause.
---------------------------------------------------------------------------

    Commenters state that the test conditions under which the DRE 
failures occurred involved feeding practices that were not common in 
the hazardous waste combustion industry. They further state that, if it 
could be ensured that hazardous waste ignited, hydrocarbon and carbon 
monoxide limits would be sufficient to ensure four-nines DRE is 
achieved continuously. Therefore, a DRE demonstration would not be 
warranted. Although we might agree in theory, the fact that tests were 
performed under these test conditions indicates that a source desired 
to operate in that fashion. Only the DRE test identified that the 
combustion failure occurred and was not susceptible to control via 
carbon monoxide and hydrocarbon emissions. This and other similar 
failures can lead to increased emissions of products of incomplete 
combustion and organic hazardous air pollutants. Also, as commenters 
acknowledge, carbon monoxide and hydrocarbon emissions were effective 
surrogates to ensure four-nines DRE only when

[[Page 52850]]

hazardous waste ignited. However, as we identified in the May 1997 
NODA, there are a number of hazardous waste combustion sources that 
operate in a manner that does not ensure ignition of hazardous waste.
    As a result of the DRE test investigation, we determined that a 
successful DRE demonstration is an effective, appropriate, and 
necessary method to identify operating parameter limits that ensure 
proper and achievable combustion of hazardous waste and to limit the 
emissions of organic hazardous air pollutants. Additionally, the DRE 
standard is a direct measure to ensure that the RCRA section 3004(o)(1) 
mandate and its protectiveness goals are being met, and also serves to 
maintain a consistent test protocol for sources combusting hazardous 
waste. The DRE demonstration requirement is also reasonable, provides a 
sound means to allow deferral of a RCRA mandate to the CAA, and 
simplifies implementation by having all stack emissions-related testing 
and compliance requirements promulgated under one statute, the CAA. 
Therefore, we retain the DRE demonstration as part of the MACT 
comprehensive performance test unless a DRE test has already been 
performed with no relevant changes.
1. MACT DRE Standard
    In today's rule, all affected sources are required to meet 99.99% 
DRE of selected Principal Organic Hazardous Constituents (POCs) that 
are as or more difficult to destroy than any organic hazardous 
pollutant fed to the unit. With one exception discussed in subsection 3 
below, this demonstration need be made only once during the operational 
life of a source, either before or during the initial comprehensive 
performance test, provided that the design, operation, and maintenance 
features do not change in a manner that could reasonably be expected to 
affect the ability to meet the DRE standard.
    The DRE demonstration involves feeding a known mass of POHC(s) to a 
combustion unit, and then measuring for that POHC(s) in stack 
emissions. If the POHC(s) is emitted at a level that exceeds 0.01% of 
the mass of the individual POHC(s) fed to the unit, the unit fails to 
demonstrate sufficient DRE.
    Operating limits for key combustion parameters are used to ensure 
four-nines DRE is maintained. The operating parameter limits are 
established based on operations during the DRE test. Examples of 
combustion parameters that are used to set operating limits include 
minimum combustion chamber temperature, minimum gas residence time, and 
maximum hazardous waste feedrate by mass. See Sec. 63.1209(j).
    Today's MACT DRE requirement is essentially the same as that 
currently required under RCRA. The main difference is that the vast 
majority of the MACT DRE demonstrations would not have to be repeated 
as often as currently required under RCRA, as discussed in section 3 
below.
2. How Can Previous Successful Demonstrations of DRE Be Used To 
Demonstrate Compliance?
    Except as discussed below, today's rule requires that, at least 
once during the operational life of a source during or before the 
initial comprehensive performance test, the source must demonstrate the 
ability to achieve 99.99% DRE and must set operating parameter limits 
to ensure that DRE is maintained. However, we recognize that many 
sources have already undergone approved DRE testing. Further, many 
facilities do not intend to modify their units design or operations in 
such a way that DRE performance or parameters would be adversely 
affected. Therefore, the Agency is allowing sources to use results from 
previous EPA or State-approved DRE demonstrations to fulfill the MACT 
four-nines DRE requirement, as well as to set the necessary operating 
limits on parameters that ensure continued compliance.
    If a facility wishes to operate under new operating parameter 
limits that could reasonably be expected to affect the ability to meet 
the standard, a new DRE demonstration must be performed before or 
concurrent with the comprehensive performance test. If the DRE 
operating limits conflict with operating parameter limits that are set 
to ensure compliance with other MACT standards, the unit must comply 
with the more stringent limits. Additionally, if a source is modified 
in such a way that its DRE operating limits are no longer applicable or 
valid, the source must perform a new DRE test. Moreover, if a source is 
modified in any way such that DRE performance or parameters are 
affected adversely, the source must perform a new DRE test.
3. DRE for Sources That Feed Waste at Locations Other Than the Flame 
Zone
    Today's rule requires sources that feed hazardous waste in 
locations other than the flame zone to perform periodic DRE tests to 
ensure that four-nines DRE continues to be achieved over the life of 
the unit. As indicated in the May 1997 NODA at 62 FR 25877, the Agency 
is concerned that these types of sources have a greater potential of 
varying DRE performance due to their waste firing practices. That is, 
due to the unique design and operation of the waste firing system, the 
DRE may vary over time, and those variations cannot be identified or 
limited through operating limits set during a single DRE test. For 
these units, we are requiring that DRE be verified during each 
comprehensive performance test and that new operating parameter limits 
be established to ensure continued compliance.
4. Sources That Feed Dioxin Wastes
    In today's rule, we are requiring all sources that feed certain 
dioxin-listed wastes (i.e., F020-F023, F026, F027) to demonstrate the 
ability to achieve 99.9999 percent (six-nines) DRE as a MACT standard. 
This requirement will serve to achieve a number of goals associated 
with today's regulations. First, under RCRA, six-nines DRE is required 
when burning certain dioxin-listed wastes. If we did not promulgate 
this requirement as a MACT standard, sources that feed dioxin-listed 
waste would be required to maintain two permits to manage their air 
emissions. Thus, by including this requirement as a MACT standard, we 
eliminate any unnecessary duplication. That outcome is contrary to our 
goal which is to limit, to the greatest extent possible, the need for 
sources to obtain two permits governing air emissions under different 
statutory authorities. Second, six-nines DRE helps to improve control 
of nondioxin organic hazardous air pollutants as well. Finally, this 
requirement properly reflects floor control for sources that feed 
dioxin-listed wastes. Currently, all sources that feed dioxin listed 
wastes must achieve six-nines DRE. Before making the decision to 
include six-nines DRE as a MACT standard, we considered whether the 
requirements could be eliminated given that we are issuing dioxin/furan 
emission standards with today's rule. We concluded, first, that we had 
not provided sufficient notice and comment to depart from the current 
regulations applicable to these sources. Second, we also decided that 
because we currently require other similar highly toxic bioaccumulative 
and persistent compounds (e.g., PCB wastes) to be fed to units that 
demonstrate six-nines DRE, a departure from that policy for RCRA dioxin 
wastes would be inconsistent. Finally, we are in discussions that may 
cause us to reevaluate our overall approach to dioxin-listed wastes, 
with the potential to impact this rule and the land disposal 
restrictions program. Any changes to our approach will be included in a 
single rulemaking that would be proposed later.

[[Page 52851]]

B. What Is the Rationale for Carbon Monoxide or Hydrocarbon Standards 
as Surrogate Control of Organic Hazardous Air Pollutants?
    Today's rule adopts limits on emissions of carbon monoxide and 
hydrocarbons as surrogates to ensure good combustion and control of 
nondioxin organic hazardous air pollutants. We require continuous 
emissions monitoring and compliance with either the carbon monoxide or 
hydrocarbon emissions standard. Sources can choose which of these two 
standards it wishes to continuously monitor for compliance. If a source 
chooses the carbon monoxide standard, it must also demonstrate during 
the comprehensive performance test compliance with the hydrocarbon 
emission standard. During this test the source also must set operating 
limits on key parameters that affect combustion conditions to ensure 
continued compliance with the hydrocarbon emission standard. These 
parameters relate to good combustion practices and are identical to 
those for which you must establish limits under the DRE standard. See 
Sec. 63.109(a)(7) and 63.1209(j). However, this source need not install 
and use a continuous hydrocarbon monitor to ensure continued compliance 
with the hydrocarbon standard. As discussed previously, the limits 
established for DRE are identical. If a source elects to use the 
hydrocarbon limit for compliance, then it must continuously monitor and 
comply with the hydrocarbon emissions standard. However, this type of 
source need not monitor carbon monoxide emissions or carbon monoxide 
operating parameters because hydrocarbon emissions are a more direct 
surrogate of nondioxin organic hazardous air pollutant emissions.
    The April 1996 NPRM proposed MACT emission standards for both 
carbon monoxide and hydrocarbon as surrogates to control emissions of 
nondioxin organic hazardous air pollutants. We also proposed that 
cement kilns comply with either a carbon monoxide or hydrocarbons 
standard due to raw material considerations.53 See 61 FR at 
17375-6. Our reliance on only carbon monoxide or only hydrocarbon has 
drawbacks, and therefore we proposed that incinerators and lightweight 
aggregate kilns comply with emissions standards for both. Nonetheless, 
we also acknowledged that requiring compliance with both carbon 
monoxide and hydrocarbon standards may be redundant, and requested 
comment on: (1) Giving sources the option of complying with either 
carbon monoxide or hydrocarbon emission standards; or (2) establishing 
a MACT standard for either carbon monoxide or hydrocarbon, but not 
both.
---------------------------------------------------------------------------

    \53\ See discussion regarding cement kilns compliance with the 
carbon monoxide and/or hydrocarbon standards in Part Four, Section 
VII.D.
---------------------------------------------------------------------------

    Comments to our proposed approach question the necessity of two 
related surrogates to control organic hazardous air pollutants. Many 
commenters assert they are capable of controlling hydrocarbon emissions 
effectively, but due to their system's unique design, they could not 
comply continuously with the carbon monoxide emission standard. In 
general, commenters prefer an approach that would afford them maximum 
flexibility in demonstrating compliance with organic control standards, 
i.e., more like option (1) in the NPRM.
    The May 1997 NODA included a refined version of the option that 
commenters prefer that allowed sources to monitor and comply with 
either a carbon monoxide or hydrocarbon emission standard. In response 
to the May 1997 NODA, commenters nearly unanimously support the option 
that allowed facilities to monitor and comply with either the carbon 
monoxide or hydrocarbon standard as surrogates to limit emissions of 
nondioxin organic hazardous air pollutants. However, a few commenters 
suggest that compliance with carbon monoxide or hydrocarbons in 
combination with DRE testing is redundant and unnecessary. However, in 
their comments, they do not address the issue of DRE failures 
associated with low carbon monoxide or hydrocarbon emissions, other 
than to state that if ignition failure was avoided, emissions of carbon 
monoxide or hydrocarbons would be good indicators of combustion 
efficiency and four-nines DRE. This does not address our concerns, 
which reflect cases in which ignition failures did not occur and in 
which destruction and removal efficiencies were not met.
    In the May 1997 NODA, we discussed another option that required 
sources to comply with the hydrocarbon emission standard and establish 
a site-specific carbon monoxide limit higher than 100 ppmv. This option 
was developed because compliance with the hydrocarbon standard assures 
control of nondioxin organic hazardous air pollutants, and a site-
specific carbon monoxide limit aids compliance by providing advanced 
information regarding combustion efficiency. However, we conclude that 
this option may be best applied as a site-specific remedy in situations 
where a source has trouble maintaining compliance with the hydrocarbon 
standard.
    Today's final rule modifies the May 1997 NODA approach slightly. 
Complying with the carbon monoxide standard now requires documentation 
that hydrocarbon emissions during the performance test are lower than 
the standard, and requires operating limits on parameters that affect 
hydrocarbon emissions. We adopt this modification because some data 
show that high hydrocarbon emissions are possible while simultaneously 
low carbon monoxide emissions are found.54
---------------------------------------------------------------------------

    \54\ In a number of instances, RCRA compliance test records 
showed that sources emitting carbon monoxide at less than 100 ppmv 
emitted hydrocarbons in excess of 10 ppmv.
---------------------------------------------------------------------------

    In the BIF rule (56 FR at 7149-50), we found that both monitoring 
and compliance with either carbon monoxide or hydrocarbon limits and 
achieving four-nines DRE is needed to ensure control of products of 
incomplete combustion (including nondioxin organic hazardous air 
pollutants) that are a result of hazardous waste combustion. DRE, 
although sensitive to identifying combustion failure modes, cannot 
independently ensure that emissions of products of incomplete 
combustion or organic hazardous air pollutants are being controlled. 
DRE can only provide the assurance that, if a hazardous waste combustor 
is operating normally, the source has the capability to transform 
hazardous and toxic organic compounds into different compounds through 
oxidation. These other compounds can include carbon dioxide, water, and 
other organic hazardous air pollutants. Because carbon monoxide 
provides immediate information regarding combustion efficiency 
potentially leading to emissions of organic hazardous air pollutants 
and hydrocarbon provides a direct measure of organic emissions, these 
two parameters individually or in combination provide additional 
control that would not be realized with the DRE operating parameter 
limits alone.55 Neither our data nor data supplied by 
commenters show that only monitoring

[[Page 52852]]

carbon monoxide, hydrocarbons, or DRE by itself can adequately ensure 
control of nondioxin organics. Therefore, the approach used in the BIF 
rule still provides the best regulatory model. We conclude in today's 
rule that hydrocarbons and carbon monoxide monitoring are not redundant 
with the DRE testing requirement to control emissions of organic 
hazardous air pollutants and require both standards. For an additional 
discussion regarding the use of hydrocarbons and carbon monoxide to 
control emissions of organic hazardous air pollutants, see USEPA, 
``Technical Support Document for HWC MACT Standards, Volume III: 
Selection of MACT Standards and Technologies,'' July 1999.
---------------------------------------------------------------------------

    \55\ We acknowledge that although hydrocarbon emissions are a 
direct measure of organic emissions, they are measured with a 
continuous emissions monitoring system known as a flame ionization 
detector. Some data suggest hydrocarbon flame ionization detectors 
do not respond with the same sensitivity to the full spectrum of 
organic compounds that may be present in the combustion gas. 
Additionally, combustion gas conditions also may affect the 
sensitivity and accuracy of the monitor. Nonetheless, monitoring 
hydrocarbons with these detectors appears to be the best method 
reasonably available to provide real-time monitoring of organic 
emissions from a hazardous waste combustor.
---------------------------------------------------------------------------

V. What Methodology Is Used To Identify MACT Floors?

    This section discusses: (1) Methods used to identify MACT floor 
controls and emission levels for the final rule; (2) the rationale for 
using hazardous waste feedrate control as part of MACT floor control 
for the metals and total chlorine standards; (3) alternative methods 
for establishing floor levels considered at proposal and in the May 
1997 NODA; and (4) our consideration of emissions variability in 
identifying MACT floor levels.
A. What Is the CAA Statutory Requirement To Identify MACT Floors?
    We identify hazardous waste incinerators, hazardous waste burning 
cement kilns, and hazardous waste burning lightweight aggregate kilns 
as source categories to be regulated under section 112. We must, 
therefore, develop MACT standards for each category to control 
emissions of hazardous air pollutants. Under CAA section 112, we may 
distinguish among classes, types and sizes of sources within a category 
in establishing such standards.
    Section 112 prescribes a minimum baseline or ``floor'' for 
standards. For new sources, the standards for a source category cannot 
be less stringent than the emission control that is achieved in 
practice by the best-controlled similar source. Section 112(d)(3). The 
standards for existing sources may be less stringent than standards for 
new sources, but cannot be less stringent than ``(A) * * * the average 
emissions limitation achieved by the best performing 12 percent of the 
existing sources (for which the Administrator has emissions 
information) * * *, in the category or subcategory for categories and 
subcategories with 30 or more sources, or (B) the average emissions 
limitation achieved by the best performing 5 sources (for which the 
Administrator has or could reasonably obtain emissions information) in 
the category or subcategory for categories and subcategories with fewer 
than 30 sources.'' Id.
    We also must consider a more stringent standard than the floor, 
referred to in today's rule as a ``beyond-the-floor'' standard. For 
each beyond-the-floor analysis, we evaluate the maximum degree in 
reduction of hazardous air pollutants determined to be achievable, 
taking into account the cost of achieving those reductions, nonair 
quality health and environmental impacts, and energy costs. Section 
112(d)(2). The object of a beyond-the-floor standard is to achieve the 
maximum degree of emission reduction without unreasonable economic, 
energy, or secondary environmental impacts.
B. What Is the Final Rule Floor Methodology?
    Today's rule establishes MACT standards for the following hazardous 
air pollutants, hazardous air pollutant groups or hazardous air 
pollutant surrogates: dioxin/furans, mercury, two semivolatile metals 
(lead and cadmium), three low volatile metals (arsenic, beryllium, and 
chromium), particulate matter, total chlorine (hydrochloric acid and 
chlorine gas), carbon monoxide, hydrocarbons, and destruction and 
removal efficiency. This subsection discusses the overall engineering 
evaluation and data analysis methods we used to establish MACT floors 
for these standards. Additional detail on the specific application of 
these methods for each source category and standard is presented in 
Part Four, Sections VI-VIII, of the preamble and in the technical 
support document.56
---------------------------------------------------------------------------

    \56\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

1. What Is the General Approach Used in This Final Rule?
    The starting point in developing standards is to determine a MACT 
floor emission level, the most lenient level at which a standard can be 
set. To identify the floor level, we first identified the control 
techniques used by the best performing sources. We designate these best 
performing sources the ``MACT pool'' and the emission control 
technologies they use we call ``MACT floor controls.''
    After identifying the MACT pool and MACT floor controls, we 
determine the emission level that the MACT floor controls are routinely 
achieving--that is, an achievable emission level taking into account 
normal operating variability (i.e., variability inherent in a properly 
designed and operated control system). This is called the floor 
emission level. To ensure that the floor emission level is being 
achieved by all sources using floor controls (i.e., not just the MACT 
pool sources), we generally consider emissions data from all sources in 
a source category that use well-designed and properly operated MACT 
floor controls. (We call the data set of all sources using floor 
controls the ``expanded MACT pool.'') Floor levels in this rule are 
generally established as the level achieved by the source in the 
expanded MACT pool with the highest emissions average 57 
using well-designed and properly operated MACT floor controls.
---------------------------------------------------------------------------

    \57\ Each source's emissions usually are expressed as an average 
of three or more emission measurements at the same set of operating 
parameters. This is because compliance is based on the average of 
three or more runs.
---------------------------------------------------------------------------

    Several commenters oppose considering emissions data from all 
sources using MACT floor controls (i.e., the expanded MACT pool) 
because they assert the expansion of the MACT pool results in inflated 
floors. If we adopt these commenters' recommendation, then many sources 
using MACT controls would not meet the standard, even though they were 
using MACT floor control. (Indeed, in some cases, other test conditions 
from the very system used to establish the MACT pool would not meet the 
standard, notwithstanding no significant change in the system's design 
and operation.) This result is inappropriate in that all sources using 
properly designed and operated MACT floor controls should achieve the 
floor emission level if the technology is well designed and operated. 
In the absence of data indicating a design or operation problem, we 
assume the floor emission level based on an expanded MACT pool reflects 
an emission level consistently achievable by MACT floor technology. Our 
resulting limits account for the fact that sources and emissions 
controls will experience normal operating variability even when 
properly designed and operated.
    The MACT floor methodology in this rule does not use a single 
uniform data analysis approach consistently across all three source 
categories and standards. Our data analysis methods vary due to: (1) 
Limitations of our emissions data and ancillary information; (2) 
emissions of some hazardous air pollutants being related to the 
feedrate of the hazardous air pollutant (e.g., semivolatile metal 
emissions are affected by semivolatile metal feedrates) while emissions 
of

[[Page 52853]]

other hazardous air pollutants are not (e.g., dioxin/furan emissions 
are related to postcombustion dioxin/furan formation rather than 
dioxin/furan feedrates); (3) the various types of emissions controls 
currently in use which do not lend themselves to one type of MACT 
analysis; and (4) consideration of existing regulations as themselves 
establishing floor levels.
    Finally, as discussed in Section D, the MACT floor levels 
established through our data analysis approaches account for emissions 
variability without the separate addition of a statistically-derived 
emissions variability factor.
2. What MACT Floor Approach Is Used for Each Standard?
    a. Dioxins and Furans. For dioxins and furans, we adopt the MACT 
floor methodology discussed in the May 1997 NODA. Based on engineering 
information and principles, we identify temperature of combustion gas 
at the particulate matter control device of 400 deg.F or less as MACT 
floor control of dioxin/furan. This technology and level of control has 
been selected because postcombustion formation of dioxin/furan is 
suppressed by lowering postcombustion gas temperatures, and formation 
is reasonably minimized at gas temperatures of 400 deg.F or below. 
Sources controlling gas temperatures to 400 deg.F or less at the 
particulate matter control device represent the level achieved by the 
median of the best performing 12 percent of sources where the source 
category has more than 30 sources (or the median of the best performing 
five sources where the source category has fewer than 30 sources).
    The next step is to identify an emissions level that MACT floor 
control achieved on a routine basis. We analyzed the emissions data 
from all sources (within each source category) using MACT floor control 
and establish the floor level equal to the highest test condition 
average.
    As discussed in greater detail in Part Four, Section VI, 
incinerators with waste heat recovery boilers present a unique 
situation for dioxin/furan control. Our data base shows that 
incinerators equipped with waste heat recovery boilers have 
significantly higher dioxin/furan emissions compared to other 
incinerators. In the waste heat recovery boiler, combustion gas is 
exposed to particles on boiler tubes within the temperature window of 
450 deg. F to 650 deg. F, which promotes surface-catalyzed formation of 
dioxin/furan. Therefore, we establish separate dioxin/furan standards 
for incinerators with waste heat boilers and incinerators without waste 
heat boilers.58 The specified floor control for both waste 
heat boilers and nonwaste heat boilers is combustion gas temperature 
control to 400 deg.F or less at the particulate matter control 
device.59 Floor levels for waste heat boiler incinerators 
are much higher, however, because of the dioxin/furan formation during 
the relatively slow temperature quench in the boiler. See the 
incinerator dioxin/furan discussion in Part Four, Section VI, of 
today's rule for more details.
---------------------------------------------------------------------------

    \58\ We concluded that separate standards to control other 
hazardous air pollutants were not needed for waste heat boiler-
equipped incinerators versus other incinerators. That is, whether or 
not the incinerator is equipped with a waste heat recovery boiler is 
only of concern for dioxin/furan emissions, not the other hazardous 
air pollutants.
    \59\ Wet particulate matter control devices (e.g., venturi 
scrubbers) inherently preclude dioxin/furan formation because: (1) 
They do not suspend particulate matter in the combustion gas flow as 
do fabric filters and electrostatic precipitators, and (2) gas 
temperatures are below 400 deg.F in the scrubber. Given this, floor 
control is use of a wet particulate matter control device or control 
of combustion gas temperature to 400 deg.F or below at the inlet to 
a dry particulate matter control device.
---------------------------------------------------------------------------

    b. What MACT Floor Methodology Is Used for Particulate Matter? We 
adopt a final MACT floor methodology for particulate matter based on 
the approaches discussed in the May 1997 NODA. For incinerators, the 
final MACT floor is determined through engineering principles and 
information, coupled with analysis of the emissions data base. For 
cement kilns, we base final MACT on the existing requirements of the 
New Source Performance Standard applicable to Portland cement kilns. 
Finally, for lightweight aggregate kilns, the final floor level is 
derived directly from the emissions data base (i.e., the highest test 
condition average for sources using properly designed and operated 
floor control).
    i. Incinerators. Today's rule identifies MACT floor control as 
either a well-designed, operated, and maintained fabric filter, 
ionizing wet scrubber, or electrostatic precipitator, based on 
engineering information and an evaluation of the particulate matter 
control equipment used by at least the median of the best performing 12 
percent of sources and the emission levels achieved. These types of 
particulate matter control equipment routinely and consistently achieve 
superior particulate matter performance relative to other controls used 
by the incinerator source category and thus represent MACT. Using 
generally accepted engineering information and principles, we then 
identify an emission level that well-designed, operated and maintained 
fabric filters, ionizing wet scrubbers, and electrostatic precipitators 
routinely achieve.
    The floor level is not directly identified from the emissions data 
base as the highest test condition average for sources using a fabric 
filter, ionizing wet scrubber, or electrostatic precipitator. The 
hazardous waste combustor incinerator data base, however, was used as a 
tool to determine if the identified floor level, established on 
generally accepted engineering information and principles, is in 
general agreement with available particulate matter data. This is 
because we do not have adequate data on the features of the control 
devices to accurately distinguish only those devices that are well-
designed, operated, and maintained and thus representative of MACT. 
Several sources in the emissions data base that are equipped with 
fabric filters, ionizing wet scrubbers, or electrostatic precipitators 
have emission levels well above the emission levels of other sources 
equipped with those devices. This strongly suggests that the higher 
levels are not representative of those achieved by well-designed, 
operated, and maintained units, even when normal operating variability 
is considered. We accordingly did not use these data in establishing 
the standard. See Kennecott v. EPA, 780 F.2d 445, 458 (4th Cir. 1985) 
(EPA ``can reject data it reasonably believes to be unreliable 
including performance data that is higher than other plants operating 
the same control technology.'')
    ii. Cement Kilns. As discussed in the May 1997 NODA and in more 
detail in the standards section for cement kilns in Part Four, Section 
VII, we base the MACT floor emission level on use of a fabric filter or 
electrostatic precipitator to achieve the New Source Performance 
Standard for Portland cement kilns. The MACT floor is equivalent to and 
expressed as the current New Source Performance Standard of 0.15 kg/Mg 
dry feed (0.30 lb/ton dry feed). In the NPRM and the May 1997 NODA, we 
proposed to express the particulate matter standard on a concentration 
basis. However, because we are not yet requiring sources to document 
compliance with the particulate matter standard by using a particulate 
matter continuous emissions monitoring system in this final rule, we 
establish and express the floor emission level equivalent to the New 
Source Performance Standard. Commenters' concerns about separate MACT 
pools for particulate matter, semivolatile metals, and low volatile 
metals are discussed in Part Four, Section VII.
    iii. Lightweight Aggregate Kilns. All lightweight aggregate kilns 
burning

[[Page 52854]]

hazardous waste are equipped with fabric filters. We could not 
distinguish only those sources with fabric filters better designed, 
operated, and maintained than others, and thus represent MACT control. 
Because we could not independently use engineering information and 
principles to otherwise distinguish which well-designed, operated, and 
maintained fabric filters are routinely achieving levels below the 
highest test condition average in the emissions data base (i.e., 
considering the high inlet grain loadings for lightweight aggregate 
kilns), we establish the floor level as that highest test condition 
average emission level. Commenters concerns about a high floor level 
and separate MACT pools for particulate matter, semivolatile metals, 
and low volatile metals are discussed in Part Four, Section VIII.
    c. Metals and Total Chlorine. This rule establishes MACT standards 
for mercury; semivolatile metals comprised of combined emissions of 
lead and cadmium; low volatility metals comprised of combined emissions 
of arsenic, beryllium, and chromium; and total chlorine comprised of 
combined emissions of hydrogen chloride and chlorine gas. As shown by 
the following analysis, these hazardous air pollutants are all 
controlled by the best performing sources, at least in part, by 
feedrate control of the metal or chlorine in the hazardous waste. In 
addition to hazardous waste feedrate control, some of the hazardous air 
pollutants also are controlled by air pollution control equipment. Both 
semivolatile metals and low volatile metals are controlled by a 
combination of hazardous waste metal feedrate control and by 
particulate matter control equipment. Total chlorine is controlled by a 
combination of feedrate control and, for hazardous waste incinerators, 
scrubbing equipment designed to remove acid gases.
    i. How Are the Metals and Chlorine Floor Control(s) Identified? We 
follow the language of CAA section 112(d)(3) to identify the control 
techniques used by the best performing sources. The hazardous waste 
incinerator and hazardous waste cement kiln source categories are 
comprised of 186 and 33 sources, respectively. From the statutory 
language, we conclude that for this analysis the control techniques 
used by the best performing 6% of sources represents the average of the 
best performing 12% of the sources in those categories. It follows, 
therefore, that floor control for metals and chlorine is the 
technique(s) used by the best performing 12 incinerators and two cement 
kilns.
    Because the hazardous waste lightweight aggregate kiln source 
category is comprised of only 10 sources, we follow the language of 
section 112(d)(3)(B) to identify the control technique(s) used by the 
three best performing sources, which represents the median of the best 
performing five sources.
    Our floor control analysis indicates that the best performing 12 
incinerators, two cement kilns, and three lightweight aggregate kilns 
all use hazardous waste feedrate control to limit emissions of mercury, 
semivolatile metal, low volatile metal, and total chlorine. For the 
semivolatile and low volatile metals, the best performing sources also 
use particulate matter control as part of the floor control technique. 
In addition, the best performing incinerator sources also control total 
chlorine and mercury with wet scrubbing. Accordingly, we identify floor 
control for semivolatile metal and low volatile metal as hazardous 
waste feedrate control plus particulate matter control, and floor 
control for incinerators for total chlorine and mercury as hazardous 
waste feedrate control plus wet scrubbing.
    ii. What is the Rationale for Using Hazardous Waste Feedrate 
Control as MACT Floor Control Technique? As discussed above, MACT floor 
control for mercury, semivolatile metals, low volatile metals, and 
total chlorine is based on, or at least partially based on, feedrate 
control of metal and chlorine in the hazardous waste. The feedrate of 
metal hazardous air pollutants will affect emissions of those 
pollutants, and the feedrate of chlorine will affect emissions of total 
chlorine (i.e., hydrochloric acid and chlorine gas) because metals and 
chlorine are elements and are not destroyed during combustion. 
Emissions controls, if any, control only a percentage of the metal or 
total chlorine fed. Therefore, as concentrations of metals and total 
chlorine in the inlet to the control device increase, emissions 
increase.
    At proposal, we identified hazardous waste feedrates as part of the 
technology basis for the proposed floor emission 
standards.60 MACT maximum theoretical emission 
concentrations 61 (MTECs) were established individually for 
mercury, semivolatile metals, low volatile metals, and total chlorine 
at a level equal to the highest MTEC of the average of the best 
performing 12% of sources. For some hazardous air pollutants, hazardous 
waste feedrate control of metals and chlorine was identified as the 
sole component of floor control (i.e., where the best performing 
existing sources do not use pollution control equipment to remove the 
hazardous air pollutant). Examples include mercury and total chlorine 
from cement kilns. For other hazardous air pollutants, we identified 
hazardous waste feedrate control of metals and chlorine as a partial 
component of MACT floor control (e.g., floor control for semivolatile 
metals include good particulate matter control in addition to feedrate 
control of semivolatile metals in hazardous waste).
---------------------------------------------------------------------------

    \60\ See 61 FR at 17366.
    \61\ We developed a term, Maximum Theoretical Emissions 
Concentration, to compare metals and chlorine feedrates across 
sources of different sizes. MTEC is defined as the metals or 
chlorine feedrate divided by the gas flow rate, and is expressed in 
g/dscm.
---------------------------------------------------------------------------

    In the May 1997 NODA, we continued to consider hazardous waste 
feedrate control of metals and chlorine as a valid floor control 
technology. However, rather than defining a specific MACT control 
feedrate level (expressed as a MTEC), we instead relied on another 
analysis tool, an emissions breakpoint analysis, to identify sources 
feeding metals and/or chlorine at high (and not MACT) levels. At the 
time, we believed that the breakpoint analysis was a less problematic 
approach to identify sources using MACT floor control than the 
approaches proposed initially.62
---------------------------------------------------------------------------

    \62\ Comments had objected to our proposed approach of defining 
MTECs as too reliant on engineering inspection of the data.
---------------------------------------------------------------------------

    Given commenters' subsequent concerns with the emissions breakpoint 
analysis as well (see discussion in Section C below), we conclude that 
specifying MTECs as MACT control (partially or solely) is necessary to 
properly reflect the feedrate component of MACT control.
    Notwithstanding how the MACT floor MTEC is defined, many commenters 
suggest that our consideration of hazardous waste feedrate as a floor 
control technique is inappropriate in a technology-based rulemaking and 
not permissible under the CAA. Commenters also state that hazardous 
waste feedrate control is not a control technique due to the wide 
variations in metals and chlorine in the hazardous waste generated at a 
single facility location. Further, they believe even greater variations 
occur in metals and chlorine levels in the hazardous waste generated at 
multiple production sites representing different industrial sectors. 
Thus, commenters suggest that basing a floor emission level on data 
from sources that feed hazardous waste with low levels of metals or 
chlorine is tantamount to declaring that wastes with higher levels of 
metals or chlorine are not to be generated. Other

[[Page 52855]]

commenters note, however, that hazardous waste feedrate control must be 
considered as a floor control technique because feedrate control is 
being used as a control means to comply with existing RCRA regulations 
for these combustors. Still other commenters recommend that we 
establish uniform hazardous waste feedrate limits (i.e., base the 
standard on an emission concentration coupled with a hazardous waste 
feedrate limit on metals and chlorine) across all three hazardous waste 
combustor source categories. Please refer to Part Five, Section 
VII.D.3.c.iv of today's preamble and the Comment Response Document for 
detailed responses to these comments.
    We do not accept the argument that control of hazardous waste 
metals and chlorine levels in hazardous waste cannot be part of the 
floor technology. First, control of hazardous air pollutants in 
hazardous waste feedstock(s) can be part of a MACT standard under 
section 112(d)(2)(A), which clearly indicates that material 
substitution can be part of MACT. Second, hazardous waste combustors 
are presently controlling the level of metal hazardous air pollutants 
and chlorine in the hazardous waste combusted because of RCRA 
regulatory requirements. (See Sec. 266.103(c)(1) and (j) where metal 
and chlorine feedrate controls are required, and where monitoring of 
feedrates are required.) Simply because these existing controls are 
risk-based, rather than technology-based, does not mean that they are 
not means of controlling air emissions cognizable under the CAA. Floor 
standards are to be based on ``emission limitation[s]'' achieved by the 
best existing sources. An ``emission limitation'' includes ``a 
requirement established by the * * * Administrator which limits the 
quantity, rate, or concentration of emissions. * * * including any 
requirement relating to the operation * * * of a source. * * *'' CAA 
section 302(k). This is precisely what current regulations require to 
control metal and chlorine levels in hazardous waste feed.
    Commenters also note that contemplated floor levels were lower than 
the feed limits specified in current regulations for boilers and 
industrial furnaces. This is true, but not an impediment to identifying 
achievable MACT floor levels. Actual performance levels can serve as a 
basis for a floor. An analogy would be where a group of facilities 
achieve better capture efficiency from air pollution control devices 
than required by existing rule. That level of performance (if generally 
achievable) can serve as the basis for a floor standard. Accordingly, 
we use hazardous waste feedrate, entirely or partially, to determine 
floor levels and beyond-the-floor levels for mercury, semivolatile 
metals, low volatile metals, and total chlorine.
    iii. How Are Feedrate and Emissions Levels Representative of MACT 
Floor Control Identified? After identifying feedrate control as floor 
control, we use a data analysis method called the ``aggregate feedrate 
approach'' to establish floor control hazardous waste feedrate levels 
and emission levels for mercury, semivolatile metals, low volatile 
metals, and total chlorine. The first step in the aggregate feedrate 
approach is to identify an appropriate level of aggregated mercury, 
semivolatile metals, low volatile metals, and total chlorine feedrate 
control, expressed as a MTEC, being achieved in practice by the best 
performing incinerator, cement kiln and lightweight aggregate kiln 
sources. This aggregate MTEC level is derived only from the sources 
using MACT floor emission controls.
    The aggregate feedrate approach involves four steps: (1) 
Identifying test conditions in the data base where data are available 
to calculate hazardous waste feedrate MTECs for all three metal 
hazardous air pollutant groups and total chlorine; (2) screening out 
test conditions where a source was not using the MACT floor emission 
control device for hazardous air pollutants that are cocontrolled by an 
air pollution control device 63; (3) ranking the individual 
hazardous air pollutant MTECs, from the different source test 
conditions, from lowest to highest and assigning each a numerical rank, 
with a rank of one being the lowest MTEC; and (4) summing, for each 
test condition, the individual ranking for each of the hazardous air 
pollutants to determine a composite ranking. The total sum is used to 
provide an overall assessment of the aggregate level of hazardous air 
pollutants in the hazardous waste for each test condition. The 
hazardous waste feed streams with lower total sums (i.e., hazardous air 
pollutant levels) are ``cleaner'' in aggregate than those with higher 
total sums.64 (See the technical support document for more 
details on this procedure.65)
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    \63\ For example, to potentially be considered a MACT-controlled 
incinerator with respect to both the emissions control device and 
hazardous waste metals and chlorine feedrate, the incinerator must 
use a wet scrubber for hydrochloric acid and mercury control and 
must use either a fabric filter, ionizing wet scrubber, or 
electrostatic precipitator and achieve the floor particulate matter 
level of 0.015 gr/dscf. Similarly, cement kilns must achieve the 
particulate matter MACT floor (for this analysis only, the New 
Source Performance Standard was converted to an estimated equivalent 
stack gas concentration of 0.03 gr/dscf) and lightweight aggregate 
kilns must meet the particulate matter MACT floor of 0.025 gr/dscf. 
There is no MACT floor hydrochloric acid emissions control device 
for cement kilns and lightweight aggregate kilns.
    \64\ This aggregate hazardous waste MTEC ranking is done 
separately for each of the three combustor source categories.
    \65\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
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    The aggregate MTEC ranking process results in aggregate feedrate 
data from nine incinerators, 10 cement kilns, and 10 lightweight 
aggregate kilns from which to select an appropriate level of feedrate 
control representative of MACT floor control.66 We 
considered selecting the source with either the highest or lowest 
aggregate MTEC in each source category to represent MACT floor control, 
but did not believe this was appropriate based on concerns about 
representativeness and achievability. We conclude that it is 
reasonable, however, to consider the best 50% of the sources for which 
we have data in each source category as the best performing sources. 
This is because, for incinerators and cement kilns, we have only a few 
sources with complete aggregate MTEC data relative to the size of the 
source category. The best 50% of the sources for these categories 
equates to five sources, given that we have aggregate MTEC data for 
nine incinerators and 10 cement kilns. For lightweight aggregate kilns, 
this equates also to five sources given that we have aggregate MTEC 
data for 10 lightweight aggregate kiln sources.
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    \66\ Only nine incinerators were ultimately used because (1) We 
have complete metal emissions data on relatively few sources, and 
(2) many sources do not use particulate matter floor control, a 
major means of controlling semivolatile metals and low volatile 
metals.
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    Additionally, we conclude it is appropriate to identify a feedrate 
MTEC representative of floor control based on the median of the best 
performing five sources. In selecting a representative sample and 
identifying the appropriate MTEC floor control level, we draw guidance 
from section 112(d)(3)(B), in which Congress requires the Agency to use 
the average of the best performing five sources when faced with small 
source categories (i.e., less than 30 sources), and therefore limited 
data, to establish a MACT floor. In addition, this methodology is 
reasonable and appropriate because it allows consideration of a number 
of best performing sources (i.e., five), which is within the range of 
reasonable values we could have selected.
    We considered an approach that selected both the control technique 
and level of control as the average of the best performing 12% of 
incinerator and

[[Page 52856]]

cement kiln sources for which we have aggregate MTEC data. This 
approach resulted in using only the best single source as 
representative of MACT floor control for all existing sources because 
there are only nine incinerators and 10 cement kilns for which we have 
adequate aggregate data. However, the level of feedrate control 
achieved by the single best performing existing source is likely not 
representative of the range of higher feedrate levels achieved by the 
best performing existing sources and, indeed, would inappropriately 
establish as a floor what amounts to a new source standard.
    The final step of the aggregate feedrate approach is to determine 
an emission level that is routinely achieved by sources using MACT 
floor control(s). Similar to the April 1996 NPRM and May 1997 NODA, we 
evaluated all available data for each test condition to determine if a 
hazardous air pollutant is fed at levels at or below the MACT floor 
control MTEC. If so, the test condition is added to the expanded MACT 
pool for that hazardous air pollutant.67 We then define the 
floor emission level for the hazardous air pollutant/hazardous air 
pollutant group as the level achieved by the source with the highest 
emissions average in the MACT expanded pool.
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    \67\ The expanded MACT pool for each hazardous air pollutant is 
comprised of test conditions from sources equipped with the 
prescribed MACT floor emission control device, if any, and feeding 
hazardous waste at an MTEC not exceeding the MACT floor MTEC for 
that hazardous air pollutant.
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    The aggregate feedrate approach is a logical and reasonable 
outgrowth of the aggregate hazardous air pollutant approach to 
establish floor emission levels that we discussed in the April 1996 
NPRM. The initial proposal determined MACT floors separately for each 
hazardous air pollutant controlled by a different control technology, 
but we also proposed an alternative whereby floors would be set on the 
basis of a source's performance for all hazardous air pollutants.
    Many commenters prefer the total aggregate hazardous air pollutant 
approach over the individual hazardous air pollutant approach because 
it better ensures that floor levels would be simultaneously achievable. 
However, we reject the total aggregate approach because it tends to 
result in floors that are likely to be artificially high, reflective of 
limited emissions data for all hazardous air pollutants at each 
facility. These floor levels, therefore, would not reflect performances 
of the best performing sources for particular hazardous air pollutants. 
We are assured of simultaneous achievability in our final methodology 
by: (1) Establishing the MACT floor feedrate control levels on an 
aggregate basis for metals and chlorine, as discussed above, rather 
than for each individual hazardous air pollutant; (2) using the 
particulate matter MACT pool to establish floor levels for particulate 
matter, semivolatile metals, and low volatile metals; and (3) ensuring 
that floor controls are not technically incompatible. In fact, our 
resulting floor emission levels are already achieved in practice by 9 
to 40 percent of sources in each of the three source categories, 
clearly indicating simultaneously achievable standards.68
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    \68\ Our analysis shows that approximately nine percent of 
incinerators, 27 percent of cement kilns, and 40 percent of 
lightweight aggregate kilns currently operating can meet all of the 
floor levels simultaneously. See USEPA, ``Final Technical Support 
Document For HWC MACT Standards, Volume V: Emissions Estimates and 
Engineering Costs,'' July 1999.
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C. What Other Floor Methodologies Were Considered?
    This is a brief overview of the major features of the MACT floor 
methodologies that we proposed in the April 1996 NPRM or discussed in 
the May 1997 NODA, accompanied by our rationale for not pursuing those 
methodologies in this final rule.
1. April 19, 1996 Proposal
    We proposed the same general approach to identify floor control and 
floor emission levels as used in today's final rule. The proposal 
contained an approach to identify the controls used by the best 
performing sources (i.e., the MACT pool) and then identify an emission 
level that those controls are achieving. To identify the floor emission 
level, we considered emissions from all sources using properly designed 
and operated controls (i.e., the expanded MACT pool) and established a 
preliminary floor level as the highest test condition average for those 
sources.
    There are three major differences between the proposed approach and 
today's final approach, however:
    a. Emissions Variability. At proposal, we added a statistically-
derived emissions variability factor to the highest test condition 
average in the expanded MACT pool. Today we conclude that emissions 
variability is considered inherently in the floor methodology. (See 
discussion in section D below for our rationale for not using a 
statistically-derived variability factor.)
    b. MACT Pool for Particulate Matter, Semivolatile Metals, and Low 
Volatile Metals. At proposal, we identified separate and different MACT 
pools (and associated MACT controls) for particulate matter, 
semivolatile metals, and low volatile metals, even though all three are 
controlled by a particulate matter control device. Commenters said this 
is inappropriate and we concur. Specifying the MACT floor particulate 
matter emission control device individually for these pollutants is 
likely to result in three different definitions of floor control. Thus, 
the same particulate matter control device would need to meet three 
different design specifications. As a practical matter, the more 
stringent specification would prevail. But, this highlights the 
impracticability of evaluating floor emission control for these 
standards individually rather than in the aggregate.
    As discussed in the May 1997 NODA, today's approach uses the same 
initial MACT pool to establish the floor levels for particulate matter, 
semivolatile metals, and low volatile metals. The initial MACT pool is 
comprised of those sources meeting the emission control component of 
MACT control. To establish the semivolatile metal and low volatile 
metal floor levels, the particulate matter MACT pool is then analyzed 
to consider MACT hazardous waste feedrate control first for 
semivolatile metals and then for low volatile metals, using the 
aggregate feedrate approach discussed above.
    c. Definition of MACT Control. At proposal, we defined MACT 
emissions control by specifying the design of the emissions control 
device. Commenters suggested that this was problematic because: (1) Our 
data base had limited data on design of the control device; (2) some of 
our available data were incorrect; and (3) the parameters the Agency 
was using to characterize MACT control did not adequately correlate 
with control efficiency. Given these concerns, our May 1997 NODA 
contained an emissions breakpoint approach to identify those sources 
that appeared to have anomalously higher emissions than other sources 
in the potential MACT pool. Our rationale was that given the 
anomalously high emissions, those sources were not, in fact, using MACT 
control.
    Commenters express serious concerns about the validity of the 
nonstatistical approach used to identify the breakpoint. After 
considering various statistical approaches to identify an emissions 
breakpoint, we conclude that the emissions breakpoint approach is 
problematic.69 For these reasons, we are

[[Page 52857]]

not defining MACT emissions control by design parameters or using an 
emissions breakpoint approach to identify MACT emissions or feedrate 
control. Rather, the MACT floor emission control equipment, where 
applicable, is defined generically (e.g., electrostatic precipitator, 
fabric filter), and the aggregate feedrate approach is used to define 
MACT floor feedrates. We believe the aggregate feedrate approach 
addresses the concerns that commenters raise on the proposed approach 
because it more clearly defines MACT control and relies less on 
engineering judgment.
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    \69\ To improve the rigor of our breakpoint approach, we 
investigated a modified Rosner ``outlier'' test that: (1) Uses a 
single tailed test to consider only high ``outliers'' (i.e., test 
conditions that anomalously high emissions, not necessarily true 
outliers in the statistical sense); (2) presumes that any potential 
``outliers'' are at the 80th percentile value or higher; and (3) has 
a confidence level of 90 percent. We abandoned this statistical 
approach because: (1) Although modifications to the standard Rosner 
test were supportable, the modified test has not been peer-reviewed; 
(2) although the target confidence level was 90 percent, the true 
significance level of the test, as revised, is inappropriately low--
approximately 80 percent; and (3) the ``outlier'' test does not 
identify MACT-like test conditions because it only identifies 
anomalously high test conditions rather than the best performing 
test conditions.
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2. May 1997 NODA
    We have incorporated into the final rule several of the procedures 
discussed in the May 1997 NODA. The NODA explained why it is 
inappropriate to add a statistically-derived emissions variability 
factor to the highest test condition average of the expanded MACT pool. 
Despite comments to the contrary, we conclude that emissions 
variability is inherently considered in the floor methodology. See 
discussion in section D below.
    In addition, the NODA discussed using the same initial MACT pool to 
establish the floor levels for particulate matter, semivolatile metals, 
and low volatile metals. We use this same approach in this final rule. 
Commenters generally concurred with that approach.
    As discussed above, we considered using an emissions breakpoint 
technique, but conclude that this approach is problematic and did not 
use the approach for this rule.
D. How Is Emissions Variability Accounted for in Development of 
Standards?
    The methodology we use to establish the final MACT emission 
standards intrinsically accounts for emissions variability without 
adding statistically-derived emissions variability factors. Many 
commenters strongly suggest that statistically-derived emissions 
variability factors must be added to the emission levels we identify 
from the data base as floor emission levels to ensure that the 
standards are routinely achievable.70 Other commenters 
suggest that our floor methodology inherently accounts for emissions 
variability. We discuss below the types of emissions variability and 
why we conclude that emissions variability is inherently accounted for 
by our methodology.
---------------------------------------------------------------------------

    \70\ One commenter recommends specific statistical approaches to 
calculate variability factors and provides examples of how the 
statistical methods should be applied to our emissions data base. 
See comment number CS4A-00041.
---------------------------------------------------------------------------

    We account for three types of emissions variability in establishing 
MACT standards: (1) Within test condition variability among test runs 
(a test condition is comprised of at least three runs that are 
averaged); (2) imprecision in the stack test method; and (3) source-to-
source emissions variability attributable to source-specific factors 
affecting the performance of the same MACT control device. (See, e.g. 
FMC Corp. v. Train, 539 F.2d 973, 985-86 (4th Cir. 1976), holding that 
variability in performance must be considered when ascertaining whether 
a technology-based standard is achievable.) The following sections 
discuss the way in which we account for these types of variability in 
the final rule.
1. How Is Within-Test Condition Emissions Variability Addressed?
    Inherent process variability will cause emissions to vary from run-
to-run within a test condition, even if the stack method is 100 percent 
precise and even though the source is attempting to maintain constant 
operating conditions. This is caused by many factors including: Minor 
changes in the feedrate of feedstreams; combustion perturbations (e.g., 
uncontrollable, minor fluctuations in combustion temperature or fan 
velocity); changes in the collection efficiency of the emission control 
device caused by fluctuations in key parameters (e.g., power input to 
an electrostatic precipitator); and changes in emissions of materials 
(e.g., sulfur dioxide) that may cause test method interferences.
    At proposal, we used a statistical approach to account for 
emissions variability. See 61 FR at 17366. The statistical approach 
identified an emissions variability factor, which was added to the log-
mean of the emission level being achieved based on the available 
``short-term'' compliance test data. We called this emission level the 
``design level.'' The variability factor was calculated to ensure that 
the design level could be achieved 99 percent of the time, assuming 
average within-test condition emissions variability for the source 
using MACT control.
    In the May 1997 NODA, we discussed alternative emission standards 
developed without using a statistically-derived variability factor. 
Adding such a variability factor was determined inappropriate because 
it sometimes resulted in nonsensical results. For example, the 
particulate matter MACT floor level for incinerators under one floor 
methodology would have been higher than the current RCRA standard 
allows, simply due to the impact of an added variability factor. In 
other cases, the floor levels would have been much higher than our 
experience would indicate are routinely being achieved using MACT 
control. We reasoned that these inappropriate and illogical results may 
flow from either the data base used to derive the variability factor 
(e.g., we did not have adequate information to screen out potentially 
outlier runs on a technical basis) or selecting an inappropriate floor-
setting test condition as the design level (e.g., we did not have 
adequate information on design, operation, and maintenance of emissions 
control equipment used by sources in the emissions data base to 
definitively specify MACT control).
    Consequently, we reasoned that adequately accounting for within 
test condition emissions variability is achieved where relatively large 
data sets are available to evaluate for identifying the floor level. 
Large sets of emissions data from MACT sources, which have emissions 
below the floor level, are likely to represent the range of emissions 
variability. For small data sets (e.g., dioxin/furan emissions for 
waste heat recovery boiler equipped incinerators; dioxin/furan 
emissions data for lightweight aggregate kilns), we acknowledged that 
the same logic would not apply. For these small data sets, the floor 
level was set at the highest run for the MACT source with the highest 
test condition average emissions. Many commenters suggest that our 
logic was flawed. Commenters say that, if we desire the floor level to 
be achievable 99 percent of the time (i.e., the basis for the 
statistically-derived variability factor at proposal), the emissions 
data base is far too small to identify the floor level as the highest 
test condition average for sources using MACT control.
    We conclude, however, that the final floor levels identified, using 
the procedures discussed above (i.e., without adding a statistically-
derived emissions variability factor), are levels that can be 
consistently achieved by well designed, operated, and maintained MACT 
sources. We

[[Page 52858]]

conclude this because our emissions data base is comprised of 
compliance test data generated when sources have an incentive to 
operate under worst case conditions (e.g., spiking metals and chlorine 
in the waste feed; detuning the emissions control equipment). Sources 
choose to operate under worst case conditions during compliance testing 
because the current RCRA regulations require that limits on key 
operating parameters not exceed the values occurring during the trial 
burn. Therefore, these sources conduct tests in a manner that will 
establish a wide envelope for their operating parameter limits in order 
to accommodate the expected variability (e.g., variability in types of 
wastes, combustion system parameters, and emission control parameters). 
See 56 FR at 7146 where EPA likewise noted that certain RCRA operating 
permit test conditions are to be ``representative of worst-case 
operating conditions'' to achieve needed operating flexibility. One 
company that operates several hazardous waste incinerators at three 
locations comments that, because of the current RCRA compliance regime, 
which is virtually identical to the compliance procedures of today's 
MACT rule, ``the result is that units must be tested at rates which are 
at least three standard deviations harsher than normal operations and 
normal variability in order to simulate most of the statistical 
likelihood of allowable emission rates.'' 71 The commenter 
also states that because of the consequences of exceeding an operating 
parameter limit under MACT, ``* * * clearly a source will test under 
the worst possible operating conditions in order to minimize future 
(exceedances of the limits).'' Finally, the commenter says that 
``Because of variability and the stiff consequences of exceeding these 
limits, operators do not in fact operate their units anywhere near the 
limits for sustained periods of time, but instead tend to operate 
several standard deviations below them, or at about 33 to 50% of the 
limits.'' 72
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    \71\ See Comment No. CS4A-00029.A, dated August 16, 1996.
    \72\ To estimate the compliance cost of today's rule, we assumed 
that sources would design their systems to meet an emission level 
that is 70% of the standard, herein after called the ``design 
level.''
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    We conclude from these comments, which are consistent with 
engineering principles and with many discussions with experts from the 
regulated community, that MACT sources with compliance test emissions 
at or below the selected floor level are achieving those levels 
routinely because these test conditions are worst-case and are defined 
by the source itself to ensure 100 percent compliance with the relevant 
standard.
    We acknowledge, however, that mercury is a special case because our 
mercury emission data may not be representative of worst-case 
conditions. As discussed in Section I.B.3 above, sources did not 
generally spike mercury emissions during RCRA compliance testing 
because they normally feed mercury at levels resulting in emissions 
well below current limits.73 Although our data base for 
mercury is comprised essentially of normal emissions, emissions 
variability is adequately accounted for in setting floor levels. First, 
mercury emissions variability is minimal because the source can readily 
control emissions by controlling the feedrate of mercury.74 
For cement and lightweight aggregate kilns, mercury is controlled 
solely by controlling feedrate. Given that there is no emission control 
device that could have perturbations affecting emission rates, 
emissions variability at a given level of mercury feedrate control is 
relatively minor. Any variability is attributable to variability in 
feedrate levels due to feedstream sampling and analysis imprecision, 
and stack method imprecision (see discussion below).
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    \73\ Three of 23 incenerators used to define MACT floor (i.e., 
sources for which mercury feedrate data are available) are known to 
have spiked mercury. No cement kilns used to define MACT floor 
(e.g., excluding sources that have stopped burning hazardous waste) 
are known to have spiked mercury. Only one of ten lightweight 
aggregate kilns used to define MACT floor is known to have spiked 
mercury.
    \74\ Although incenerators are generally equipped with wet 
scrubbers that can have a mercury removal efficiency of 15 to 60 
percent, feedrate control is nonetheless the primary means of 
mercury emissions control because of the relatively low removal 
efficiency provided by wet scrubbers.
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    Second, our emissions data indicate that the mercury floor levels 
are being achieved by a wide margin, which is a strong indication that 
a variability factor is not needed. Only one of the 15 incinerators 
using MACT floor control exceeds the design level for the floor 
emission level.75 In addition, only seven of 45 incinerators 
for which we have mercury emissions data exceed the design level, and 
two of those eight are know to have spiked mercury in the hazardous 
waste feed during compliance testing. Only six of the 45 incinerators 
exceed the floor emission level.
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    \75\ Commenters note that the mercury levels fed during RCRA 
compliance testing may not represent the normal range of feedrates, 
and thus the compliance test emission levels may not be 
representative of emission levels achieved in practice. Given that 
only one of 15 incinerators using floor control exceeds the design 
level, it appears that the floor emission level is, in fact, being 
achieved in practice. Some of these 15 sources were likely feeding 
mercury at the high end of their normal range, even though others 
may have been feeding mercury at normal or below normal levels. This 
is also the situation of cement kilns where only two of 2 kilns 
using floor control exceed the design level, and for lightweight 
aggregate kilns where only one of nine kilns using floor exceeds the 
design level.
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    The situation is similar for cement kilns and lightweight aggregate 
kilns. Only two of 22 cement kilns using floor control exceed the 
design level, only five of the 33 kilns in the source category exceed 
the design level, and only one of the 33 kilns exceeds the floor 
emission level. Only one of nine lightweight aggregate kilns using 
floor control exceeds the design level, and only two of the 10 kilns in 
the source category exceed the design level (and one of those kilns is 
known to have spiked mercury in the hazardous waste feed during 
compliance testing). Only one of the 10 kilns exceeds the floor 
emission level, and that kiln spiked mercury.
    We conclude from this analysis that the mercury floor emission 
levels in this rule are readily achieved in practice even though our 
mercury emissions data were not spiked (i.e., they may not represent 
worst-case emissions), and therefore a separate variability factor is 
not needed.
2. How Is Waste Imprecision in the Stack Test Method Addressed?
    Method precision is a measure of how closely emissions data are 
grouped together when measuring the same level of stack emissions 
(e.g., using a paired or quad test train). Method imprecision is 
largely a function of the ability of the sampling crew and analytical 
laboratory to routinely follow best practices. Precision can be 
affected by: (1) Measurement of ancillary parameters including gas flow 
rate, pressure, and temperature; (2) recovery of materials from the 
sampling train; and (3) cleaning, concentrating, and quantitating the 
analyte.
    Several commenters state that we must add a factor to the selected 
floor level to account for method imprecision in addition to a factor 
to account for within-test condition emissions variability. We 
investigated the imprecision for the stack methods used to document 
compliance with today's rule and determined that method imprecision may 
be significant for some hazardous air pollutant/method 
combinations.76 Our results indicate, however, that method 
precision is much better than commenters claim, and that as additional 
data sets become available,

[[Page 52859]]

the statistically-derived precision bars for certain pollutants are 
reasonably expected to be reduced significantly. This is mainly because 
data should become available over a wider range of emission levels thus 
reducing the uncertainty that currently results in large precision bar 
projections for some hazardous air pollutants at emission levels that 
are not close to the currently available paired and quad-train 
emissions data.
---------------------------------------------------------------------------

    \76\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    We conclude that method imprecision, in selecting the floor levels 
for hazardous waste combustors, is adequately addressed for the same 
reasons that we accounted for within-test condition emissions 
variability. Method precision is simply a factor that contributes to 
within-test condition variability. As discussed above, sources consider 
emissions variability when defining their compliance test operating 
conditions to balance emissions standards compliance demonstrations 
with the need to obtain a wide operating envelope of operating 
parameter limits.
3. How Is Source-to-Source Emissions Variability Addressed?
    If the same MACT control device (i.e., same design, operating, and 
maintenance features) were used at several sources within a source 
category, emissions of hazardous air pollutants from the sources could 
vary. This is because factors that affect the performance of the 
control device could vary from source to source. Even though a device 
has the same nominal design, operating, and maintenance features, those 
features could never be duplicated exactly. Thus, emissions could vary 
from source to source.
    We agree that this type of emissions variability must be accounted 
for in the standards to ensure the standards are achieved in practice. 
Source-to-source emissions variability is addressed by identifying the 
floor emission level as the highest test condition average for sources 
in the expanded MACT pool, as discussed above.77
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    \77\ Because of the need to account for this type of 
variability, we disagree with those commenters recommending that: 
(1) The floor emission level be identified as the average emission 
level achieved by the 12 percent of source with the lowest 
emissions; and (2) it is inappropriate to base the floor emission 
level on sources using floor control but that are not within the 12 
percent of sources with the lowest emissions (i.e., the expanded 
MACT pool should not be used to identify floor emission levels). The 
floor emission level must be achieved in practice by sources using 
the appropriately designed and operated floor control. Thus, 
emission levels being achieved by all sources using the 
appropriately designed and operated floor control (i.e., including 
sources using floor control but having emission levels greater than 
the average of the emissions achieved by the 12 percent of sources 
with the lowest emissions) must be considered when identifying the 
floor emission level.
---------------------------------------------------------------------------

    The test condition average emissions for sources in the expanded 
MACT pool for most standards often vary over several orders of 
magnitude. That variability is attributable partially to the type of 
source-to-source emissions variability addressed here as well as the 
inclusion of sources with varying levels of MACT control in the pool. 
Sources are included in the expanded MACT pool if they have controls 
equivalent to or better than MACT floor controls. We are unable to 
identify true source-to-source emissions variability for sources that 
actually have the same MACT controls because we are unable to specify 
in sufficient detail the design, operating, and maintenance 
characteristics of MACT control. Such information is not readily 
available. Therefore, we define MACT control only in general terms. 
This problem (and others) are addressed in today's rule by selecting 
the MACT floor level based on the highest test condition average in the 
expanded MACT pool, which accounts for source-to-source variability.
    We also conclude that the characteristics of the emissions data 
base coupled with the methodology used to identify the floor emission 
level adequately accounts for emissions variability so that the floor 
level is routinely achieved in practice by sources using floor control. 
As further evidence, we note that a large fraction--50 to 100 percent--
of sources in the data base currently meet the floor levels regardless 
of whether they currently use floor control.78
---------------------------------------------------------------------------

    \78\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
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VI. What Are the Standards for Existing and New Incinerators?

A. To Which Incinerators Do Today's Standards Apply?
    The standards promulgated today apply to each existing, 
reconstructed, and newly constructed incinerator (as defined in 40 CFR 
260.10) burning hazardous waste. These standards apply to all major 
source and area source incinerator units and to all units whether they 
are transportable or fixed sources. These standards also apply to 
incinerators now exempt from RCRA stack emission standards under 
Secs. 264.340(b) and (c).\79\ Additionally, these standards apply to 
thermal desorbers that meet the definition of a RCRA incinerator, and 
therefore, are not regulated under subpart X of part 264.
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    \79\ Sections 264.340(b) and (c) exempt from stack emission 
standards incinerators (a) burning solely ignitable, corrosive or 
reactive wastes under certain conditions, and (b) if the waste 
contains no or insignificant levels of hazardous constituents.
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B. What Subcategorization Options Did We Evaluate?
    We considered whether it would be appropriate to subcategorize 
incinerators based on several factors discussed below and conclude that 
subcategorization is not necessary. However, for waste heat recovery 
boiler-equipped incinerators, we establish a separate emission standard 
solely for dioxin/furan. We explained our rationale for separate 
dioxin/furan standards for waste heat recovery boilers in the May 1997 
NODA (62 FR 24220). We said that waste heat recovery boilers emit 
significantly higher dioxin/furan emissions than other incinerators, 
probably because the heat recovery boiler precludes rapid temperature 
quench of the combustion gases to below 400 deg.F, therefore warranting 
separate standards for dioxin/furan only (i.e., the waste heat boiler 
does not affect achievability of the other emission standards).
    We considered several options for subcategorizing the hazardous 
waste incinerator source category based on: (1) Size of the unit (e.g., 
small and large incinerators); (2) method of use of the hazardous waste 
incinerator (e.g., commercial hazardous waste incinerator, captive (on-
site) unit); (3) facility design (e.g., rotary kiln, liquid injection, 
fluidized bed, waste heat boiler), and (4) type of waste fed (e.g., 
hazardous waste mixed with radioactive waste, munitions, liquid, solid 
or aqueous wastes). Subcategorization would be appropriate if one or 
more of these factors affected achievability of emission standards that 
were established without subcategorization. In the May 1997 NODA (62 FR 
24219), we stated that subdividing the hazardous waste incinerator 
source category by size or method of use (such as commercial or on-
site) would be inappropriate because it would not result in standards 
that are more achievable. Many of the standards would be the same for 
the subcategories while the remainder would be more stringent. That 
conclusion is not altered by any of the changes in today's final rule. 
Therefore, subcategorization would add complexity without any tangible 
achievability benefits.
    In the same notice, we also requested comment on subcategorization 
and/or a deferral of standards for mixed waste incinerators based on a 
comment from the Department of Energy that this type of incinerator has 
several unique features that warrant subcategorization.

[[Page 52860]]

There are three Department of Energy mixed waste incinerators. Each 
mixed waste incinerator has a different type of operation and different 
air pollution control devices, and two of the sources have high dioxin/
furan and mercury emissions (several times the dioxin/furan standards 
adopted in today's rule). We received several comments on the mixed 
waste incinerator issue. These commenters contend that, because of the 
radioactive component of the wastes, mixed waste incinerators pose 
greater than average risk, and regulating these facilities should not 
be deferred. These commenters also note that the MACT controls are not 
incompatible with mixed waste incinerators and thus these incinerators 
can readily achieve the emission standards. We agree that MACT controls 
are compatible with mixed waste incinerators, with one exception 
discussed below, and do not establish a mixed waste incinerator 
subcategory.
    The standards promulgated today are generally achievable by all 
types and sizes of incinerators when using MACT controls. We recognize, 
however, that each of the possible subcategories considered has some 
unique features. At the same time, upon consideration of each 
individual issue, we conclude that unique features of a particular 
hazardous waste incinerator can be better dealt with on an individual 
basis (through the permit process or through petitions) instead of 
through extensive subcategorization. As an example, we agree with the 
Department of Energy's contentions that feedstream testing for metals 
is problematic for mixed waste incinerators due to radioactivity of the 
waste and because risk from metal emissions is minimal in mixed waste 
incinerators that use HEPA filters to prevent radioactive emissions. 
Section 63.1209(g)(1) of today's rule provides a mechanism for 
petitioning the Administrator for use of an alternative monitoring 
method.80 This petition process appears to be an appropriate 
vehicle for addressing the concerns expressed by the Department of 
Energy about feedstream testing for metals and use of HEPA filters at 
its mixed waste incinerators.
---------------------------------------------------------------------------

    \80\ The petition for an alternative monitoring method should be 
included in the comprehensive performances test plan submitted for 
review and approval.
---------------------------------------------------------------------------

    In summary, our decision not to subcategorize hazardous waste 
incinerators is based on four reasons:
    (1) Size differences among hazardous waste incinerators do not 
necessarily reflect process, equipment or emissions differences among 
the incinerators. Many small size hazardous waste incinerators have 
emissions lower than those promulgated today even though they are not 
regulated to those low levels.
    (2) Types and concentrations of uncontrolled hazardous air 
pollutants are similar for all suggested subcategories of hazardous 
waste incinerators.
    (3) The same type of control devices, such as electrostatic 
precipitators, fabric filters, and scrubbers, are used by all hazardous 
waste incinerators to control emissions of particular hazardous air 
pollutants.
    (4) The standards are achievable by all types and sizes of well 
designed and operated incinerators using MACT controls.
C. What Are the Standards for New and Existing Incinerators?
1. What Are the Standards for Incinerators?
    We discuss in this section the basis for the emissions standards 
for incinerators. The emissions standards are summarized below:

                                   Standards for Existing and New Incinerators
----------------------------------------------------------------------------------------------------------------
                                                               Emissions standard \1\
    Hazardous air pollutant or    ------------------------------------------------------------------------------
hazardous air pollutant surrogate    Existing sources                          New sources
----------------------------------------------------------------------------------------------------------------
Dioxin /Furan....................  0.20 ng TEQ \2\/     0.20 ng TEQ/dscm.
                                    dscm; or 0.40 ng
                                    TEQ/dscm and
                                    temperature at
                                    inlet to the
                                    initial
                                    particulate matter
                                    control device  400 deg.F.
Mercury..........................  130 g/dscm  45 g/dscm.
Particulate Matter...............  34mg/dscm (0.015gr/  34mg/dscm (0.015gr/dscf).
                                    dscf).
Semivolatile Metals..............  240 g/dscm  24 g/dscm.
Low Volatile Metals..............  97 g/dscm.  97 g/dscm.
Hydrochloric Acid/Chlorine Gas...  77 ppmv............  21 ppmv.
Hydrocarbons 3, 4................  10 ppmv (or 100      10 ppmv (or 100 ppmv carbon monoxide).
                                    ppmv carbon
                                    monoxide).
Destruction and Removal            99.99% for each      Same as for existing incinerators.
 Efficiency.                        specific principal
                                    organic hazardous
                                    constituent,
                                    except 99.9999%
                                    for specified
                                    dioxin-listed
                                    wastes.
----------------------------------------------------------------------------------------------------------------
\1\ All emission levels are corrected to 7 percent oxygen.
\2\ Toxicity equivalent quotient, the international method of relating the toxicity of various dioxin/furan
  congeners to the toxicity of 2,3,7,8-TCDD.
\3\ Hourly rolling average. Hydrocarbons reported as propane.
\4\ Incinerators that elect to continuously comply with the carbon monoxide standard must demonstrate compliance
  with the hydrocarbon standard of 10ppmv during the comprehensive performance test.

2. What Are the Standards for Dioxins and Furans?
    We establish a dioxin/furan standard for existing incinerators of 
either 0.20 ng TEQ/dscm, or a combination of dioxin/furan emissions up 
to 0.40 ng TEQ/dscm and temperature at the inlet to the initial dry 
particulate matter control device not to exceed 400 deg.F.81 
Expressing the standard as a temperature limit as well as a dioxin/
furan concentration limit provides better control of dioxin/furan, 
because sources operating at temperatures below 400 deg.F generally 
have lower emissions and is consistent with the current practice of 
many sources. Further, without the lower alternative TEQ limit of 0.20 
ng/dscm, sources that may be operating dry particulate matter control 
devices at temperatures higher than 400 deg.F while achieving dioxin/
furan emissions below 0.20 ng TEQ/dscm would nonetheless be required to 
incur costs to lower gas temperatures. This would not be appropriate 
because lowering gas temperatures in this case would likely

[[Page 52861]]

achieve limited reductions in dioxin/furan emissions (i.e., because 
emissions are already below 0.20 ng TEQ).
---------------------------------------------------------------------------

    \81\ Incinerators that use wet scrubbers as the initial 
particulate matter control device are presumed to meet the 400 deg.F 
temperature requirement. Consequently, as a practical matter, the 
standard for such incinerators is simply 0.4 ng TEQ/dscm.
---------------------------------------------------------------------------

    For new incinerators, the dioxin/furan standard is 0.20 ng TEQ/
dscm. We discuss below the rationale for these standards.
    a. What is the MACT Floor for Existing Sources? We establish the 
same MACT floor control, as was evaluated in the May 1997 NODA, based 
on the revised data base and the refinements to the analytical 
approaches. This floor control is based on quenching of combustion 
gases to 400 deg.F or below at the dry particulate matter control 
device.82 We selected a temperature of 400 deg.F because 
that temperature is below the temperature range for optimum surface-
catalyzed dioxin/furan formation reactions--450 deg.F to 650 deg.F--and 
most sources operate their particulate matter control device below that 
temperature. In addition, temperature is an important control parameter 
because dioxin/furan emissions increase exponentially as combustion gas 
temperatures at the dry particulate matter control device increase 
above 400 deg.F.
---------------------------------------------------------------------------

    \82\ The temperature limit applies at the inlet to a dry 
particulate matter control device that suspends particulate matter 
in the combustion gas stream (e.g., electrostatic precipitator, 
fabric filter) such that surface-catalyzed formation of dioxin/furan 
is enhanced. The temperature limit does not apply to a cyclone 
control device, for example.
---------------------------------------------------------------------------

    We identify a MACT floor level of 0.40 ng TEQ/dscm for incinerators 
other than those equipped with waste heat recovery boilers. As 
discussed in the May 1997 NODA, the floor level of 0.40 ng TEQ/dscm is 
based on the highest nonoutlier test condition for sources equipped 
with dry particulate matter control devices operated at temperatures of 
400 deg.F or below or wet particulate matter control devices. We 
screened out four test conditions from three facilities because they 
have anomalously high dioxin/furan emissions and are not representative 
of MACT control practices.83 Three of these test conditions 
are from sources that had other test conditions with emission averages 
well below 0.40 ng TEQ/dscm, indicating that the same facilities can 
achieve lower emission levels in different operating modes.
---------------------------------------------------------------------------

    \83\ USEPA, ``Technical Support Document for HWC MACT Standards, 
Volume III: Selection of MACT Standards and Technologies,'' July 
1999, Section 3.1.1.
---------------------------------------------------------------------------

    We identify a MACT floor level for waste heat boiler-equipped 
hazardous waste incinerators of 12 ng TEQ/dscm based on the highest 
emitting individual run for sources equipped with dry particulate 
matter control devices operated at temperatures of 400 deg.F or below 
or wet particulate matter control devices. We use the highest run to 
set the floor level rather than the average of the runs for the test 
condition to address emissions variability concerns given that we have 
a very small data set for waste heat boilers. All waste heat boiler-
equipped hazardous waste incinerators meet this floor level, except for 
a new test conducted after the publication of the May 1997 NODA at high 
temperature conditions that resulted in dioxin/furan emission levels of 
47 ng TEQ/dscm. This source is not using MACT control, however, because 
the temperature at the particulate matter control device exceeded 
400 deg.F. Thus, we do not consider emissions from this source in 
identifying the floor level.
    We received numerous and diverse comments on the April 1996 
proposal and the May 1997 NODA. While some commenters consider the 
dioxin/furan standards too high, a large number comment that the 
standards are too stringent. Many comment that the methodology used for 
calculating the dioxin/furan MACT floor level is inappropriate and that 
the cost-effectiveness of the standards is not reasonable. In 
particular, some commenters suggest separating ``fast quench'' and 
``slow quench'' units. We have fully addressed this latter concern 
because we now establish separate dioxin/furan standards for waste heat 
boilers given that they are a fundamentally different type of process 
and that they have higher dioxin/furan emissions because of the slow 
quench across the boiler. We address the other comments elsewhere in 
the preamble and in the comment response document.
    Approximately 65% of all test conditions at all incinerator sources 
are achieving the 0.40 ng TEQ/dscm level, and over 50% of all test 
conditions achieve the 0.20 ng TEQ/dscm level. We estimate that 
approximately 60 percent of incinerators currently meet the TEQ limit 
as well as the temperature limit. Under the statute, compliance costs 
are not to be considered in MACT floor determinations. For purposes of 
compliance with Executive Order 12866 and the Regulatory Flexibility 
Act, we calculated the annualized cost for hazardous waste incinerators 
to achieve the dioxin/furan MACT floor levels. Assuming that no 
hazardous waste incinerator exits the market due to MACT standards, the 
annual cost is estimated to be $3 million, and the standards will 
reduce dioxin/furan emissions nationally by 3.4 g TEQ per year from the 
baseline emissions level of 24.8 g TEQ per year.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? We investigated the use of activated carbon injection, along 
with limiting temperatures at the inlet to the initial dry particulate 
matter control device to 400 deg.F,84 to achieve two 
alternative beyond-the-floor emission levels: (1) 0.40 ng TEQ/dscm for 
waste heat boiler-equipped incinerators (i.e., slow quench) to reduce 
their emissions to the floor level for other incinerators; and (2) 0.20 
ng TEQ/dscm for all incinerators. Activated carbon injection technology 
is feasible and proven to reduce dioxin/furan emissions by 99 percent 
or greater.85 It is currently used by one waste heat boiler-
equipped hazardous waste incinerator (Waste Technologies Industries in 
East Liverpool, Ohio) and many municipal waste combustors.86 
The removal efficiency of an activated carbon injection system is 
affected by several factors including carbon injection rate and 
adsorption quality of the carbon. Thus, activated carbon injection 
systems can be used by waste heat boiler-equipped incinerators to 
achieve alternative beyond-the-floor emissions of either 0.40 ng TEQ/
dscm or 0.20 ng TEQ/dscm.
---------------------------------------------------------------------------

    \84\ Limiting the temperature at the dry particulate matter 
control device reduces surface-catalyzed formation of dioxin/furan 
and enhances the adsorption of dioxin/furan on the activated carbon.
    \85\ USEPA, ``Technical Support Document for HWC MACT Standards, 
Volume III: Selection of MACT Standards and Technologies,'' July 
1999.
    \86\ We have established in a separate rulemaking that activated 
carbon injection is MACT floor control for municipal waste 
combustors.
---------------------------------------------------------------------------

    We conclude that a beyond-the-floor emission level of 0.40 ng TEQ/
dscm for waste heat boiler-equipped incinerators is cost-effective but 
a 0.20 ng TEQ/dscm emission level for all incinerators is not cost-
effective. We estimate that 23 waste heat boiler-equipped incinerators 
will need to install activated carbon injection systems at an 
annualized cost of approximately $6.6 million. This will result in a 
sizable reduction of 17.9 g TEQ dioxin/furan emissions per year and 
will provide an 84 percent reduction in emissions from the floor 
emission level (21.4 g TEQ per year) for all hazardous waste 
incinerators. This represents a cost-effectiveness of $370,000 per gram 
TEQ removed.
    When we evaluated the alternative beyond-the-floor emission level 
of 0.20 ng TEQ/dscm for all incinerators, we determined that 80 
hazardous waste incinerators would incur costs to reduce dioxin/furan 
emissions by 19.5 g TEQ from the floor level (21.4 g TEQ) at an 
annualized cost of $16.1 million. The cost-effectiveness would be 
$827,000 per gram of TEQ removed. In addition,

[[Page 52862]]

we determined that the vast majority of these emissions reductions 
would be provided by waste heat boiler-equipped incinerators, and would 
be provided by the beyond-the-floor emission level of 0.40 ng TEQ/dscm 
discussed above. The incremental annualized cost of the 0.20 ng TEQ/
dscm option for incinerators other than waste heat boiler-equipped 
incinerators would be $9.5 million, and would result in an incremental 
reduction of only 1.6 g TEQ per year. This represents a high cost for a 
very small additional emission reduction from the floor, or a cost-
effectiveness of $6.0 million per additional gram of TEQ dioxin/furan 
removed. Accordingly, we conclude that the 0.20 ng TEQ/dscm beyond-the-
floor option is not cost-effective.
    We note that dioxin/furan are some of the most toxic compounds 
known due to their bioaccumulative potential and wide range of adverse 
health effects, including carcinogenesis, at exceedingly low doses. We 
consider beyond-the-floor reduction of dioxin/furan emissions a prime 
environmental and human health consideration. As discussed above, our 
data base indicates that a small subset of incinerators--those equipped 
with waste heat recovery boilers--can emit high levels of dioxin/furan, 
up to 12 ng TEQ/dscm, even when operating the dry particulate matter 
control device at 400 deg.F. We are concerned that such high 
dioxin/furan emission levels are not protective of human health and the 
environment, as mandated by RCRA. If dioxin/furan emissions from waste 
heat boiler-equipped incinerators are not reduced by a beyond-the-floor 
emission standard, omnibus RCRA permit conditions would likely be 
needed in many cases. This would defeat our objective of having only 
one permitting framework for stack air emissions at hazardous waste 
incinerators (except in unusual cases). Thus, the beyond-the-floor 
standard promulgated today for waste heat boiler-equipped incinerators 
is not only cost-effective, but also an efficient approach to meed the 
Agency's RCRA mandate.
    Some commenters suggest that the standard for waste heat boiler-
equipped hazardous waste incinerators, which is based on activated 
carbon injection, be set at levels achieved by activated carbon 
injection at the Waste Technologies Industries facility--an average of 
0.07 ng TEQ/dscm. We determined that this would not be appropriate 
because of concerns that such a low emission level may not be routinely 
achievable. An emission level of 0.07 ng TEQ/dscm represents a 99.4 
percent reduction in emissions from the floor level of 12 ng TEQ/dscm. 
Although activated carbon injection can achieve dioxin/furan emissions 
reductions of 99 percent and higher, we are concerned that removal 
efficiency may decrease at low dioxin/furan emission levels. We noted 
our uncertainty about how much activated carbon injection control 
efficiency may be reduced at low dioxin/furan concentrations in the May 
1997 NODA (62 FR at 24220). Several commenters agree with our concern, 
including Waste Technologies Industries.87 No commenters 
provide data or information to the contrary. Because we have data from 
only one hazardous waste incinerator documenting that an emission level 
of 0.07 ng TEQ can be achieved, we are concerned that an emission level 
that low may not be routinely achievable by all sources.
---------------------------------------------------------------------------

    \87\ Waste Technologies Industries suggested, however, that 
after experience with activated carbon injection systems has been 
attained by several hazardous waste incinerators, the Agency could 
then determine whether an emission level of 0.07 ng TEQ/dscm is 
routinely achievable. See comment number 064 in Docket F-97-CS4A-
FFFFF.
---------------------------------------------------------------------------

    c. What Is the MACT Floor for New Sources? For new sources, the CAA 
requires that the MACT floor be the level of control used by the best 
controlled single source. As discussed above, one source, the Waste 
Technologies Industries (WTI) incinerator in Liverpool, Ohio, uses 
activated carbon injection. Therefore, we identify activated carbon 
injection as MACT floor control for new sources. To establish the MACT 
floor emission level that is being achieved in practice for sources 
using activated carbon injection, data are available from only WTI. WTI 
is achieving an emission level of 0.07 ng TEQ/dscm. As discussed above, 
we are concerned that emission level may not be routinely achievable 
because the removal efficiency of activated carbon injection may be 
reduced at such low emission levels. An emission level of 0.20 ng TEQ/
dscm is routinely achievable, however. We note that activated carbon 
injection is MACT floor control for dioxin/furan at new large municipal 
waste combustors. We established a standard of 13 ng/dscm total mass 
``equal to about 0.1 to 0.3 ng/dscm TEQ'' for these sources (60 FR 
65396 (December 19, 1995)), equivalent to approximately 0.20 ng TEQ/
dscm. We conclude, therefore, that a floor level of 0.20 ng TEQ/dscm is 
achievable for new sources using activated carbon injection and 
accordingly set this as the standard.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? As 
discussed in the May 1997 NODA, a beyond-the-floor standard below 0.20 
ng TEQ/dscm would not be appropriate. Although installation of carbon 
beds would enable new hazardous waste incinerators to achieve lower 
dioxin/furan levels, we do not consider the technology to be cost-
effective. The reduction in dioxin/furan emissions would be very small, 
while the costs of carbon beds would be prohibitively high. In 
addition, due to the very small dioxin/furan reduction, the benefit in 
terms of cancer risks reduced also will be very small. Therefore, we 
conclude that a beyond-the-floor standard for dioxin/furan is not 
appropriate.
3. What Are the Standards for Mercury?
    We establish a mercury standard for existing and new incinerators 
of 130 and 45 g/dscm respectively. We discuss below the 
rationale for these standards.
    a. What Is the MACT Floor for Existing Sources? We are establishing 
the same MACT floor level as proposed, 130 g/dscm although, as 
discussed below, the methodology underlying this standard has changed 
from proposal. At proposal, the floor standard was based on the 
performance of either: (1) Feedrate control of mercury at a maximum 
theoretical emission concentration not exceeding 19 g/dscm; or 
(2) wet scrubbing in combination with feedrate control of mercury at a 
level equivalent to a maximum theoretical emission concentration not 
exceeding 51 g/dscm. In the May 1997 NODA, we reevaluated the 
revised data base and defined MACT control as based on performance of 
wet scrubbing in combination with feedrate control of mercury at a 
level equivalent to a maximum theoretical emission concentration of 50 
g/dscm and discussed a floor level of 40 g/dscm.
    Several commenters object to our revised methodology and are 
concerned that we use low mercury feedrates to define floor control. 
These commenters state that standards should not be based on sources 
feeding very small amounts of a particular metal, but rather on their 
ability to minimize the emissions by removing the hazardous air 
pollutant. As discussed previously, we maintain that hazardous waste 
feedrate is an appropriate MACT control technique. We agree with 
commenters' concerns, however, that previous methodologies to define 
floor feedrate control may have identified sources feeding anomalously 
low levels of a metal (or chlorine). To address this concern, we have 
revised the floor determination methodology for mercury, semivolatile 
metals, low volatile metals and total chlorine. A

[[Page 52863]]

detailed description of this methodology--the aggregate feedrate 
approach--is presented in Part Four, Section V of this preamble. 
Adopting this aggregate feedrate approach, we identify a mercury 
feedrate level that is approximately five times higher than the May 
1997 NODA level and higher than approximately 70% of the test 
conditions in our data base.
    Wet scrubbers also provide control of mercury (particularly mercury 
chlorides). Given that virtually all incinerators are equipped with wet 
scrubbers (for control of particulate matter or acid gases), we 
continue to define floor control as both hazardous waste feedrate 
control of mercury and wet scrubbing. The MACT floor based on the use 
of wet scrubbing and feedrate control of mercury is 130 g/
dscm.\88\
---------------------------------------------------------------------------

    \88\ This is coincidentally the same floor level as proposed, 
notwithstanding the use of a different methodology.
---------------------------------------------------------------------------

    The floor level is being achieved by 80% of the test conditions in 
our data base of 30 hazardous waste incinerators. As already discussed 
above, consideration of costs to achieve MACT floor standards play no 
part in our MACT floor determinations, but we nevertheless estimate 
costs to the hazardous waste incinerator universe for administrative 
purposes. We estimate that 35 hazardous waste incinerators, assuming no 
market exit by any facility, will need to adopt measures to reduce 
mercury emissions at their facilities by 3.46 Mg from the current 
baseline of 4.4 Mg at an estimated annualized cost $12.2 million, 
yielding a cost-effectiveness of $3.6 million per Mg of mercury 
reduced.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? As required by statute, we evaluated more stringent beyond-
the-floor controls for further reduction of mercury emissions from the 
floor level. Activated carbon injection systems can achieve mercury 
emission reductions of over 85 percent and we proposed them as beyond-
the-floor control in the April 1996 NPRM. In the May 1997 NODA, we 
reevaluated the use of activated carbon injection 89 as 
beyond-the-floor control, but cited significant cost-effectiveness 
concerns. We reiterate these concerns here. Our technical support 
document 90 provides details of annualized costs and 
reductions that can be achieved.
---------------------------------------------------------------------------

    \89\ Flue gas temperatures would be limited to 400 deg.F at the 
point of carbon injection to enhance mercury removal.
    \90\ USEPA, ``Technical Support Document for HWC MACT Standards, 
Volume V: Emission Estimates and Engineering Costs,'' July 1999.
---------------------------------------------------------------------------

    In addition, we considered a beyond-the-floor level of 50 
g/dscm based on limiting the feedrate of mercury in the 
hazardous waste (i.e., additional feedrate control beyond floor 
control), and conducted an evaluation of the cost of achieving this 
reduction to determine if this beyond-the-floor level would be 
appropriate. The national incremental annualized compliance cost to 
meet this beyond-the-floor level, rather than comply with the floor 
controls, would be approximately $4.2 million for the entire hazardous 
waste incinerator industry and would provide an incremental reduction 
in mercury emissions nationally beyond the MACT floor controls of 0.7 
Mg/yr, yielding a cost-effectiveness of $10 million per additional Mg 
of mercury reduced. Thus, potential benefits in relation to costs are 
disproportionately low, and we conclude that beyond-the-floor mercury 
controls for hazardous waste incinerators are not warranted. Therefore, 
we are not adopting a mercury beyond-the-floor standard.
    Many commenters object to our beyond-the-floor standards as 
proposed, citing high costs for achieving relatively small mercury 
emission reductions, and compare the cost-effectiveness numbers with 
regulations of other sources (electric utilities, municipal and medical 
waste incinerators). Although comparison between rules for different 
sources is not directly relevant (see, e.g., Portland Cement 
Association v. Ruckelshaus 486 F.2d 375, 389 (D.C. Cir. 1973)), we 
nevertheless agree that the cost of a mercury beyond-the-floor standard 
in relation to benefits is substantial. Some commenters, as well as the 
peer review panel, state that beyond-the-floor levels are not supported 
by a need based on risk. Although the issue of residual risk can be 
deferred under the CAA, an immediate question must be addressed if RCRA 
regulation of air emissions is to be deferred. Our analysis \91\ 
indicates that mercury emissions at the floor level do not pose a 
serious threat to the human health and environment and that these 
standards are adequately protective to satisfy RCRA requirements as a 
matter of national policy, subject, of course, to the possibility of 
omnibus permit conditions for individual facilities in appropriate 
cases.
---------------------------------------------------------------------------

    \91\ USEPA, ``Risk Assessment Support to the Development of 
Technical Standards for Emissions from Combustion Units Burning 
Hazardous Wastes: Background Information Document,'' July 1999.
---------------------------------------------------------------------------

    Some commenters state that the technical performance of activated 
carbon injection for mercury control is not adequately proven. 
Activated carbon injection performance has been adequately demonstrated 
at several hazardous waste incinerators, municipal waste combustors, 
and other devices.\92\ Our peer review panel also states that activated 
carbon injection can achieve 85% reduction of mercury emissions.\93\ 
Some commenters also state that we underestimate the cost and 
complexities of retrofitting incinerators to install activated carbon 
injection systems (e.g., air reheaters would be required in many 
cases). We reevaluated the modifications needed for retrofits of 
activated carbon injection systems and have revised the costs of 
installation.
---------------------------------------------------------------------------

    \92\ USEPA, ``Technical Support Document for HWC MACT Standards, 
Volume III: Selection of Proposed MACT Standards and Technologies,'' 
July 1999.
    \93\ Memo from Mr. Shiva Garg, EPA to Docket No. F-96-RCSP-FFFFF 
entitled ``Peer Review Panel Report in support of proposed rule for 
revised standards for hazardous waste combustors'', dated August 5, 
1996.
---------------------------------------------------------------------------

    c. What Is the MACT Floor for New Sources? Floor control must be 
based on the level of control used by the best controlled single 
source. The best controlled source in our data base uses wet scrubbing 
and hazardous waste feedrate control of mercury at a feedrate 
corresponding to a maximum theoretical emission concentration of 0.072 
g/dscm. We conclude that this feedrate is atypically low, 
however, given that the next lowest mercury feedrates in our data base 
are 63, 79, 110, and 130 g/dscm, expressed as maximum 
theoretical emission concentrations. Accordingly, we select the mercury 
feedrate for the second best controlled source under the aggregate 
feedrate approach to represent the floor control mercury feedrate for 
new sources. That feedrate is 110 g/dscm \94\ expressed as a 
maximum theoretical emission concentration, and corresponds to an 
emission level of 45 g/dscm after considering the expanded 
MACT pool (i.e., the highest emission level from all sources using 
floor control). Therefore, we establish a MACT floor level for mercury 
for new sources of 45 g/dscm.\95\ We note that, at proposal 
and in

[[Page 52864]]

the May 1997 NODA, mercury standards of 50 and 40 g/dscm 
respectively were proposed for new sources. Today's final rule is in 
the same range as those proposed emission levels.
---------------------------------------------------------------------------

    \94\ The test conditions with mercury feedrates of 63 and 79 
g/dscm do not have complete data sets for all metals and 
chlorine. Thus, these conditions cannot be used under the aggregate 
feedrate approach to define the floor level of feedrate control. 
Mercury emissions from those test conditions are used, however, to 
identify a floor emission level that is being achieved.
    \95\ In addition, this floor emission level may be readily 
achievable for new sources using activated carbon injection as floor 
control for dioxiin/furan without the need for feedrate control of 
mercury. Activated carbon injection can achieve mercury emissions 
reductions of 85 percent. Given that the upper bound mercury 
feedrate for ``normal'' wastes (i.e., without mercury spiking) in 
our data base corresponds to a maximum theoretical emission 
concentration of 300 g/dscm, such sources could achieve the 
mercury floor emission level of 45 g/dscm using activated 
carbon injection alone.
---------------------------------------------------------------------------

    d. What Are Our Beyond-the-Floor Considerations for New Sources? We 
evaluated the use of activated carbon injection as beyond-the-floor 
control for new sources to achieve emission levels lower than floor 
levels. In the April 1996 NPRM and May 1997 NODA, we stated that new 
sources could achieve a beyond-the-floor level of 4 g/dscm 
based on use of activated carbon injection. We cited significant cost-
effectiveness concerns at that level, however. We reiterate those 
concerns today.
    Many commenters object to our beyond-the-floor standards as 
proposed, citing high costs for achieving relatively small mercury 
emission reductions. They compare the proposed standards unfavorably 
with other sources' regulations (e.g., electric utilities, municipal 
and medical waste incinerators), where the cost-effectiveness values 
are much lower. As stated earlier, comparison between rules for 
different sources is not directly relevant. Nonetheless, we conclude 
that use of activated carbon injection as a beyond-the-floor control 
for mercury for new sources would not be cost-effective. We also note 
that the floor levels are adequately protective to satisfy RCRA 
requirements.
    We also considered additional feedrate control of mercury as 
beyond-the-floor control. We conclude, however, that significant 
emission reductions using feedrate control may be problematic because 
the detection limit of routine feedstream analysis procedures for 
mercury is such that a beyond-the-floor mercury emission limit could be 
exceeded even though mercury is not present in feedstreams at 
detectable levels. Although sources could potentially perform more 
sophisticated mercury analyses, cost-effectiveness considerations would 
likely come into play and suggest that a beyond-the-floor standard is 
not warranted.
4. What Are the Standards for Particulate Matter?
    We establish standards for existing and new incinerators which 
limit particulate matter emissions to 0.015 grains/dry standard cubic 
foot (gr/dscf) or 34 milligrams per dry standard cubic meter (mg/
dscm).\96\ We chose the particulate matter standard as a surrogate 
control for the metals antimony, cobalt, manganese, nickel, and 
selenium. We refer to these five metals as ``nonenumerated metals'' 
because standards specific to each metal have not been established. We 
discuss below the rationale for adopting these standards.
---------------------------------------------------------------------------

    \96\ Particulate matter is a surrogate for the metal hazardous 
air pollutants for which we are not establishing metal emission 
standards: Antimony, cobalt, manganese, nickel, and selenium.
---------------------------------------------------------------------------

    a. What Is the MACT Floor for Existing Sources? Our data base 
consists of particulate matter emissions from 75 hazardous waste 
incinerators that range from 0.0002 gr/dscf to 1.9 gr/dscf. Particle 
size distribution greatly affects the uncontrolled particulate matter 
emissions from hazardous waste incinerators, which, in turn, is 
affected by incinerator type and design, particulate matter entrainment 
rates, waste ash content, waste sooting potential and waste chlorine 
content. Final emissions from the stacks of hazardous waste 
incinerators are affected by the degree of control provided to 
uncontrolled particulate matter emissions by the air pollution control 
devices. Dry collection devices include fabric filters or electrostatic 
precipitators, while wet collection devices include conventional wet 
scrubbers (venturi type) or the newer patented scrubbers like 
hydrosonic, free jet, or the collision type. Newer hazardous waste 
incinerators now commonly use ionizing wet scrubbers or wet 
electrostatic precipitators or a combination of both dry and wet 
devices.
    The MACT floor setting procedure involves defining MACT level of 
control based on air pollution control devices used by the best 
performing sources. Control devices used by these best performing 
sources can be expected to routinely and consistently achieve superior 
performance. Then, we identify an emissions level that well designed, 
well-operated and well-maintained MACT controls can achieve based on 
demonstrated performance, and engineering information and principles.
    The average of the best performing 12 percent of hazardous waste 
incinerators use either fabric filters, electrostatic precipitators 
(dry or wet), or ionizing wet scrubbers (sometimes in combination with 
venturi, packed bed, or spray tower scrubbers). As explained in Part 
Four, Section V, we define floor control for particulate matter for 
incinerators as the use of a well-designed, operated, and maintained 
fabric filter, electrostatic precipitator, or ionizing wet scrubber. 
Sources using certain wet scrubbing techniques such as high energy 
venturi scrubbers, and novel condensation, free-jet, and collision 
scrubbers can also have very low particulate matter emission levels. We 
do not consider these devices to be MACT control, however, because, in 
general, a fabric filter, electrostatic precipitator, or ionizing wet 
scrubber will provide superior particulate matter control. In some 
cases, sources using medium or low energy wet scrubbers are achieving 
very low particulate matter emissions, but only for liquid waste 
incinerators, which typically have low ash content waste. Thus, this 
control technology demonstrates high effectiveness only under atypical 
conditions, and we do not consider it to be MACT floor control for 
particulate matter.
    We conclude that fabric filters, electrostatic precipitators, and 
ionizing wet scrubbers are routinely achieving an emission level of 
0.015 gr/dscf based upon the following considerations:
    i. Sources in our data base are achieving this emission level. Over 
75 percent of the sources in the expanded MACT pool are achieving an 
emission level of 0.015 gr/dscf. We investigated several sources in our 
data base using floor control but failing to achieve this level, and we 
found that the control devices do not appear to be well-designed, 
operated, and maintained. Some of these sources are not using superior 
fabric filter bags (e.g., Gore-tex, Nomex felt, or tri-lift 
fabrics), some exhibit salt carry-over and entrainment from a poorly 
operated wet scrubber located downstream of the fabric filter, and some 
are poorly maintained in critical aspects (such as fabric cleaning 
cycle or bag replacements). \97\
---------------------------------------------------------------------------

    \97\ USEPA, ``Technical Support Document for HWC, MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    ii. Well-designed, operated, and maintained fabric filters and 
electrostatic precipitators can routinely achieve particulate matter 
levels lower than the floor level of 0.015 gr/dscf. Levels less than 
0.005 gr/dscf were demonstrated on hazardous waste incinerators and 
municipal waste combustors in many cases. Well-designed fabric filters 
have a surface collection area of over 0.5 ft2/acfm and high 
performance filter fabrics such as Nomex and Gore-tex. Well-designed 
electrostatic precipitators have advanced power system controls (with 
intermittent or pulse energization), internal plate and electrode 
geometry to

[[Page 52865]]

allow for high voltage potential, flue gas conditioning by addition of 
water or reagents such as sulfur trioxide or ammonia to condition 
particulate matter for lower resistivity, and optimized gas 
distribution within the electrostatic precipitator. The technical 
support document identifies many hazardous waste incinerators using 
such well designed control equipment.
    iii. The 0.015 gr/dscf level is well within the accepted 
capabilities of today's particulate matter control devices in the 
market place. Vendors typically guarantee emission levels for the 
particulate matter floor control devices at less than 0.015 gr/dscf and 
in some cases, as low as 0.005 gr/dscf.
    iv. The 0.015 gr/dscf level is consistent with standards 
promulgated for other incinerator source categories burning municipal 
solid waste and medical waste, both of which are based on performance 
of fabric filters or electrostatic precipitators as MACT. Comparison of 
hazardous waste incinerator floor level to these standards is 
appropriate because particulate matter characteristics such as particle 
size distribution, loading and particulate matter type are comparable 
within the above three types of waste burning source categories.
    v. Hazardous waste incinerators that meet the 0.015 gr/dscf 
particulate matter level also generally achieve semivolatile metal 
system removal efficiencies of over 99% and low volatile metal system 
removal efficiencies over 99.9%. This indicates superior particulate 
matter collection efficiency because these metals are controlled by 
controlling fine and medium-sized particulate matter.
    vi. Over 50 percent of all test conditions in the data base, 
regardless of the type of air pollution control device used, design of 
the hazardous waste incinerator, or the type of waste burned, currently 
meet the 0.015 gr/dscf level. This includes hazardous waste 
incinerators with high particulate matter entrainment rates (such as 
fluidized bed and rotary kilns) as well as those with wastes that 
generate difficult to capture fine particulate matter, such as certain 
liquid injection facilities.
    vii. Many incinerators conducted several tests to develop the most 
flexible operating envelope for day-to-day operations, keeping in view 
the existing RCRA particulate matter standard of 0.08 gr/dscf. In many 
test conditions, they elected to meet (and be limited to) the 0.015 gr/
dscf level, although they were only required to meet a 0.08 gr/dscf 
standard.
    Many commenters object to the use of engineering information and 
principles in the selection of the MACT floor level. Some consider 
engineering information and principles highly subjective and dependent 
on reviewers' interpretation of the data, while others suggest the use 
of accepted statistical methods for handling the data. We performed 
analyses based on available statistical tools for outlier analysis and 
variability, as discussed previously, but conclude that those 
approaches are not appropriate. We continue to believe that the use of 
engineering information and principles is a valid approach to establish 
the MACT floor (i.e., to determine the level of performance 
consistently achievable by properly designed and operated floor control 
technology).
    Some commenters object to the use of ``well-designed, operated and 
maintained'' MACT controls. They consider the term too vague and want 
specific parameters and features (e.g., air to cloth ratio for fabric 
filters and power input for electrostatic precipitators) identified. We 
understand commenters' concerns but such information is simply not 
readily available. Further, many parameters work in relation with 
several others making it problematic to quantify optimum values 
separate from the other values. The system as a whole needs to be 
optimized for best control efficiency on a case-by-case basis.
    Some commenters object to our justification of particulate matter 
achievability on the basis of vendors' claims. They contend that: (1) 
Vendors' claims lack quality control and are driven by an incentive for 
sales; (2) vendors' claims are based on normal operating conditions, 
not on trial burn type conditions; and (3) MACT floor should not be 
based on theoretical performance of state-of-the-art technology. We 
would agree with the comments if the vendor information were from 
advertising literature, but instead, our analysis was based on 
warranties. The financial consequences of vendors' warranties require 
those warranties to be conservative and based on proven performance 
records, both during normal operations and during trial burn 
conditions. In any case, we are using vendor information as 
corroboration, not to establish a level of performance.
    In the May 1997 NODA (62 FR at 24222), we requested comments on the 
alternative MACT evaluation method based on defining medium and low 
energy venturi-scrubbers burning low ash wastes as an additional MACT 
control, but screening out facilities from the expanded MACT floor 
universe that have poor semivolatile metal system removal efficiency. 
The resulting MACT floor emission level under this approach would be 
0.029 gr/dscf. Many commenters agree with the Agency that this 
technique is unacceptable because it ignores a majority (over 75 
percent) of the available particulate matter data in identifying the 
MACT standard. This result is driven by the fact that corresponding 
semivolatile metal data are not available from those sources. Other 
commenters, however, suggest that venturi scrubbers should be 
designated as MACT particulate matter control. These commenters suggest 
that sources using venturi scrubbers are within the average of the best 
performing 12 percent of sources, and there is no technical basis for 
their exclusion. As stated above, we agree that well-designed and 
operated venturi scrubbers can achieve the MACT floor level of 0.015gr/
dscf under some conditions (as when burning low ash wastes), but their 
performance is generally not comparable to that of a fabric filter, 
electrostatic precipitator, or ionizing wet scrubber. Thus, we conclude 
that sources equipped with venturi scrubbers may not be able to achieve 
the floor emission level in all cases, and the floor level would have 
to be inappropriately increased to accommodate unrestricted use of 
those units.
    Some commenters state that we must demonstrate health or 
environmental benefits if the rule were to require sources to replace 
existing, less efficient air pollution control devices (e.g., venturi 
scrubbers incapable of meeting the standard) with a better performing 
device, particularly because particulate matter is not a hazardous air 
pollutant under the CAA. These comments are not persuasive and are 
misplaced as a matter of law. The MACT floor process was established 
precisely to obviate such issues and to establish a minimum level of 
control based on performance of superior air pollution control 
technologies. Indeed, the chief motivation for adopting the technology-
based standards to control emissions of hazardous air pollutants in the 
first instance was the evident failure of the very type of risk-based 
approach to controlling air toxics as is suggested by the commenters. 
(See, e.g., H. Rep. No. 490, 101st Cong. 2d Sess., at 318-19.) Inherent 
in technology-based standard setting, of course, is the possibility 
that some technologies will have to be replaced if they cannot achieve 
the same level of performance as the best performing technologies. 
Finally, with regard to the commenters' points regarding particulate 
matter not being a hazardous air pollutant, we explain

[[Page 52866]]

above why particulate matter is a valid surrogate for certain hazardous 
air pollutants, and can be used as a means of controlling hazardous air 
pollutant emissions. In addition, the legislative history appears to 
contemplate regulation of particulate matter as part of the MACT 
process. (See S. Rep. No. 228, 101st Cong. 1st Sess., at 
170.98)
---------------------------------------------------------------------------

    \98\ Control of particulate matter also helps assure that the 
standards are sufficiently protective to make RCRA regulation of 
these sources' air emissions unnecessary (except potentially on a 
site-specific basis through the omnibus permitting process). See 
Technical Support Document on Risk Assessment.
---------------------------------------------------------------------------

    We do not consider cost in selecting MACT floor levels. 
Nevertheless, for purposes of administrative compliance with the 
Regulatory Flexibility Act and various Executive Orders, we estimate 
the cost burden on the hazardous waste incinerator universe to achieve 
compliance. Approximately 38 percent of hazardous waste incinerators 
currently meet the floor level of 0.015 gr/dscf. The annualized cost 
for the remaining 115 incinerators to meet the floor level, assuming no 
market exits, is estimated to be $17.4 million. Nonenumerated metals 
and particulate matter emissions will be reduced nationally by 5.1 Mg/
yr and 1345 Mg/yr, respectively, or over 50 percent from current 
baseline emissions.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the NPRM, we proposed a beyond-the-floor emission level of 
69 mg/dscm (0.030 gr/dscf) and solicited comment on an alternative 
beyond-the-floor emission level of 34 mg/dscm (0.015 gr/dscf) based on 
improved particulate matter control. (61 FR at 17383.) In the May 1997 
NODA, we concluded that a beyond-the-floor standard may not be 
warranted due to significant cost-effectiveness considerations. (62 FR 
at 24222.)
    In the final rule, we considered more stringent beyond-the-floor 
controls that would provide additional reductions of particulate matter 
emissions using fabric filters, electrostatic precipitators, and wet 
ionizing scrubbers that are designed, operated, and maintained to have 
improved collection efficiency. We considered a beyond-the-floor level 
of 16 mg/dscm (0.007 gr/dscf), approximately one-half the floor 
emission level, for existing incinerators based on improved particulate 
matter control. We then determined the cost of achieving this reduction 
in particulate matter, with corresponding reductions in the 
nonenumerated metals for which particulate matter is a surrogate, to 
determine if this beyond-the-floor level would be appropriate. The 
national incremental annualized compliance cost for incinerators to 
meet this beyond-the-floor level, rather than comply with the floor 
controls, would be approximately $6.8 million for the entire hazardous 
waste incinerator industry and would provide an incremental reduction 
in nonenumerated metals emissions nationally beyond the MACT floor 
controls of 1.7 Mg/yr. Based on these costs of approximately $4.1 
million per additional Mg of nonenumerated metals emissions removed, we 
conclude that this beyond-the-floor option for incinerators is not 
acceptably cost-effective nor otherwise justified. Therefore, we do not 
adopt this beyond-the-floor standard. Poor cost-effectiveness would be 
particularly unacceptable here considering that these metals also have 
relatively low toxicity. Thus, the particulate matter standard for new 
incinerators is 34 mg/dscm. Therefore, the cost-effectiveness threshold 
we would select would be less than for more toxic pollutants such as 
dioxin, mercury or other metals.
    c. What Is the MACT Floor for New Sources? We proposed a floor 
level of 0.030 gr/dscf for new sources based on the best performing 
source in the data base, which used a fabric filter with an air-to-
cloth ratio of 3.8 acfm/ft\2\. In the May 1997 NODA, we reevaluated the 
particulate matter floor level and indicated that floor control for 
existing sources would also appear to be appropriate for new sources. 
We are finalizing the approach discussed in the May 1997 NODA whereby 
floor control is a well-designed, operated, and maintained fabric 
filter, electrostatic precipitator, or ionizing wet scrubber, and the 
floor emission level is 0.015 gr/dscf.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? We 
considered more stringent beyond-the-floor controls that would provide 
additional reductions of particulate matter emissions using fabric 
filters, electrostatic precipitators, and wet ionizing scrubbers that 
are designed, operated, and maintained to have improved collection 
efficiency. We considered a beyond-the-floor level of 16 mg/dscm (0.007 
gr/dscf), approximately one-half the emissions level for existing 
sources, for new incinerators based on improved particulate matter 
control. For analysis purposes, improved particulate matter control 
assumes the use of higher quality fabric filter bag material. We then 
determined the cost of achieving this reduction in particulate matter, 
with corresponding reductions in the nonenumerated metals for which 
particulate matter is a surrogate, to determine if this beyond-the-
floor level would be appropriate. The incremental annualized compliance 
cost for one new large incinerator to meet this beyond-the-floor level, 
rather than comply with floor controls, would be approximately $39,000 
and would provide an incremental reduction in nonenumerated metals 
emissions of approximately 0.05 Mg/yr.99 For a new small 
incinerator, the incremental annualized compliance cost would be 
approximately $7,500 and would provide an incremental reduction in 
nonenumerated metals emissions of approximately 0.008 Mg/yr. Based on 
these costs of approximately $0.8-1.0 million per additional Mg of 
nonenumerated metals removed, we conclude that a beyond-the-floor 
standard of 16 mg/dscm is not warranted due to the high cost of 
compliance and relatively small nonenumerated metals emission 
reductions. Poor cost-effectiveness would be particularly unacceptable 
here considering that these metals also have relatively low toxicity. 
Thus, the particulate matter standard for new incinerators is 34 mg/
dscm.
---------------------------------------------------------------------------

    \99\ Based on the data available, the average emissions in sum 
of the five nonenumerated metals from incinerators using MACT 
particulate matter control is approximately 229 g/dscm. To 
estimate emission reductions of the nonenumerated metals for 
specific test conditions, we assume a linear relationship between a 
reduction in particulate matter and these metals.
---------------------------------------------------------------------------

5. What Are the Standards for Semivolatile Metals?
    Semivolatile metals are comprised of lead and cadmium. We establish 
standards which limit semivolatile metal emissions to 240 g/
dscm for existing sources and 24 g/dscm for new sources. We 
discuss below the rationale for adopting these standards.
    a. What Is the MACT Floor for Existing Sources? As discussed in 
Part Four, Section V of the preamble, floor control for semivolatile 
metals is hazardous waste feedrate control of semivolatile metals plus 
MACT floor particulate matter control. We use the aggregate feedrate 
approach to define the level of semivolatile metal feedrate control. We 
have aggregate feedrate data for 20 test conditions from nine hazardous 
waste incinerators that are using MACT floor control for particulate 
matter. The semivolatile metal feedrate levels, expressed as maximum 
theoretical emission concentrations, for these sources range from 100 
g/dscm to 1.5 g/dscm while the semivolatile emissions range 
from 1 to 6,000 g/dscm. The MACT-defining maximum theoretical 
emission concentration is

[[Page 52867]]

5,300 g/dscm. Upon expanding the MACT pool, only the highest 
emissions test condition of 6,000 g/dscm was screened out 
because the semivolatile metal maximum theoretical emission 
concentration for this test condition was higher than the MACT-defining 
maximum theoretical emission concentration. The highest emission test 
condition in the remaining expanded MACT pool identifies a MACT floor 
emission level of 240 g/dscm.
    We originally proposed a semivolatile metal floor standard of 270 
g/dscm based on semivolatile metal feedrate control. We 
subsequently refined the emissions data base and reevaluated the floor 
methodology, and discussed in the May 1997 NODA a semivolatile metal 
floor level of 100 g/dscm. Commenters express serious concerns 
with the May 1997 NODA approach in two areas. First, they note that the 
MACT-defining best performing sources have very low emissions, not 
entirely due to the performance of MACT control, but also due to 
atypically low semivolatile metal feedrates. Second, they object to our 
use of a ``breakpoint'' analysis to screen out the outliers from the 
expanded MACT pool (which was already small due to the screening 
process to define the feedrate level representative of MACT control). 
Our final methodology makes adjustments to address these concerns. 
Under the aggregate feedrate approach, sources with atypically low 
feedrates of semivolatile metals would not necessarily drive the floor 
control feedrate level. This is because the aggregate feedrate approach 
identifies as the best performing sources (relative to feedrate 
control) those with low feedrates in the aggregate for all metals and 
chlorine. In addition, the floor methodology no longer uses the 
breakpoint approach to identify sources not using floor control. These 
issues are discussed above in detail in Part Four, Section V, of the 
preamble.
    Although cost-effectiveness of floor emission levels is not a 
factor in defining floor control or emission levels, we have estimated 
compliance costs and emissions reductions at the floor for 
administrative purposes. Approximately 66 percent of sources currently 
meet the semivolatile metal floor level of 240 g/dscm. The 
annualized cost for the remaining 64 incinerators to meet the floor 
level, assuming no market exits, is estimated to be $1.8 million. 
Semivolatile metal emissions will be reduced nationally by 55.9 Mg per 
year from the baseline emissions level of 58.5 Mg per year, a reduction 
of 95.5%.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? We considered more stringent semivolatile metal feedrate 
control as a beyond-the-floor control to provide additional reductions 
in emissions. Cost effectiveness considerations would likely come into 
play, however, and suggest that a beyond-the-floor standard is not 
warranted. Therefore, we conclude that a beyond-the-floor standard for 
semivolatile metals for existing sources is not appropriate. We note 
that a beyond-the-floor standard is not needed to meet our RCRA 
protectiveness mandate.
    c. What Is the MACT Floor for New Sources? Floor control for new 
sources is: (1) The level of semivolatile metal feedrate control used 
by the source with the lowest aggregate feedrate for all metals and 
chlorine;100 and (2) use of MACT floor particulate matter 
control for new sources (i.e., a fabric filter, electrostatic 
precipitator, or wet ionizing scrubber achieving a particulate matter 
emission level of 0.015 gr/dscf). Three sources in our data base are 
currently using the floor control selected for all new sources and are 
achieving semivolatile emissions ranging from 2 g/dscm to 24 
g/dscm. To ensure that the floor level is achievable by all 
sources using floor control, we are establishing the floor level for 
semivolatile metals for new sources at 24 g/dscm.
---------------------------------------------------------------------------

    \100\ I.e., a semivolatile metal feedrate equivalent to a 
maximum theoretical emission concentration of 3,500 g/dscm.
---------------------------------------------------------------------------

    d. What Are Our Beyond-the-Floor Considerations for New Sources? We 
considered more stringent beyond-the-floor controls (i.e., a more 
restrictive semivolatile metal feedrate) to provide additional 
reduction in emissions. We determined that cost-effectiveness 
considerations would likely be unacceptable due to the relatively low 
concentrations achieved at the floor. This suggests that a beyond-the-
floor standard is not warranted. We note that a beyond-the-floor 
standard is not needed to meet our RCRA protectiveness mandate.
6. What Are the Standards for Low Volatile Metals?
    Low volatile metals are comprised of arsenic, beryllium, and total 
chromium. We establish standards that limit emissions of these metals 
to 97 g/dscm for both existing and new incinerators. We 
discuss below the rationale for adopting these standards.
    a. What Is the MACT Floor for Existing Sources? We are using the 
same approach for low volatile metals as we did for semivolatile metals 
to define floor control. Floor control for low volatile metals is use 
of particulate matter floor control and control of the feedrate of low 
volatile metals to a level identified by the aggregate feedrate 
approach.
    The low volatile metal feedrates for sources using particulate 
matter floor control range from 300 g/dscm to 1.4 g/dscm when 
expressed as maximum theoretical emission concentrations. Emission 
levels for these sources range from 1 to 803 g/dscm. 
Approximately 60 percent of sources using particulate matter floor 
control have low volatile metal feedrates below the MACT floor 
feedrate--24,000 g/dscm, expressed as a maximum theoretical 
emission concentration.
    Upon expanding the MACT pool, the source using floor control with 
the highest emissions is achieving an emission level of 97 g/
dscm. Accordingly, we are establishing the floor level for low volatile 
metals for existing sources at 97 g/dscm to ensure that the 
floor level is achievable by all sources using floor control.
    We identified a low volatile metal floor level of 210 g/
dscm in the April 1996 proposal. The refined data analysis in the May 
1997 NODA, based on the revised data base, reduced the low volatile 
metal floor level to 55 g/dscm. As with semivolatile metals, 
commenters express serious concerns with the May 1997 NODA approach, 
including selection of the breakpoint ``outlier'' screening approach 
and use of hazardous waste incinerator data with atypically low 
feedrates for low volatile metals. We acknowledge those concerns and 
adjusted our methodology accordingly. See discussions above in Part 
Four, Section V.
    We estimated compliance costs to the hazardous waste incinerator 
universe for administrative purposes. Approximately 63 percent of 
incinerators currently meet the 97 g/dscm floor level. The 
annualized cost for the remaining 69 incinerators to meet the floor 
level, assuming no market exits, is estimated to be $1.9 million, and 
would reduce low volatile metal emissions nationally by 6.9 Mg per year 
from the baseline emissions level of 8 Mg per year.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? We considered more stringent beyond-the-floor controls (i.e., 
a more restrictive low volatile metal feedrate) to provide additional 
reduction in emissions. Due to the relatively low concentrations 
achieved at the floor, we determined that cost-effectiveness 
considerations would likely be unacceptable. Therefore, we conclude 
that a beyond-the-floor standard for low volatile metals for existing 
sources is not

[[Page 52868]]

appropriate. We note that a beyond-the-floor standard is not needed to 
meet our RCRA protectiveness mandate.
    c. What Is the MACT Floor for New Sources? We identified a floor 
level of 260 g/dscm for new sources at proposal based on the 
best performing source in the data base. That source uses a venturi 
scrubber with a low volatile metal feedrate equivalent to a maximum 
theoretical emission concentration of 1,000 g/dscm. Our 
reevaluation of the data base in the May 1997 NODA identified a floor 
level of 55 g/dscm based on use of floor control for 
particulate matter and feedrate control of low volatile metals. Other 
than the comments on the two issues of low feedrate and the 
inappropriate use of a breakpoint analysis discussed above, no other 
significant comments challenged this floor level.
    Floor control for new sources is the same as discussed in the May 
1997 NODA (i.e., use of particulate matter floor control and feedrate 
control of low volatile metals), except the floor feedrate level under 
the aggregate feedrate approach used for today's final rule is 13,000 
g/dscm. Upon expanding the MACT pool, the source using floor 
control with the highest emissions is achieving an emission level of 97 
g/dscm.101 Accordingly, we are establishing the 
floor level for low volatile metals for new sources at 97 g/
dscm to ensure that the floor level is achievable by all sources using 
floor control.
---------------------------------------------------------------------------

    \101\ The emission level for new sources achieving a feedrate 
control of 13,000 g/dscm (expressed as a maximum 
theoretical emission concentration) is the same as the emission 
level for existing sources achieving a feedrate control of 24,000 
g/dscm because sources feeding low volatile metals in the 
range of 13,000 to 24,000 g/dscm have emission levels at or 
below 97 g/dscm. Although these sources feel low volatile 
metals at higher levels than the single best feedrate-controlled 
source, their emission control devices apparently are more 
efficient. Thus, they achieved lower emissions than the single best 
feedrate-controlled source.
---------------------------------------------------------------------------

    d. What Are Our Beyond-the-Floor Considerations for New Sources? We 
considered more stringent beyond-the-floor controls (i.e., a more 
restrictive low volatile metal feedrate) to provide additional 
reduction in emissions. Because of the relatively low concentrations 
achieved, we determined that cost-effectiveness considerations would 
likely be unacceptable. Therefore, we conclude that a beyond-the-floor 
standard for low volatile metals for new sources is not appropriate. We 
note that a beyond-the-floor standard is not needed to meet our RCRA 
protectiveness mandate.
7. What Are the Standards for Hydrochloric Acid and Chlorine Gas?
    We establish standards for hydrochloric acid and chlorine gas, 
combined, for existing and new incinerators of 77 and 21 ppmv 
respectively. We discuss below the rationale for adopting these 
standards.
    a. What Is the MACT Floor for Existing Sources? Almost all 
hazardous waste incinerators currently use some type of add-on stack 
gas wet scrubbing system, in combination with control of the feedrate 
of chlorine, to control emissions of hydrochloric acid and chlorine 
gas. A few sources use dry or semi-dry scrubbing, alone or in 
combination with wet scrubbing, while a few rely upon feedrate control 
only. Wet scrubbing consistently provides a system removal efficiency 
of over 99 percent for various scrubber types and configurations. 
Current RCRA regulations require 99% removal efficiency and most 
sources are achieving greater than 99.9 percent removal efficiency. 
Accordingly, floor control is defined as wet scrubbing achieving a 
system removal efficiency of 99 percent or greater combined with 
feedrate control of chlorine.
    The floor feedrate control level for chlorine is 22 g/
dscm, expressed as a maximum theoretical emission concentration, based 
on the aggregate feedrate approach. The source in the expanded MACT 
pool (i.e., all sources using floor control) with the highest emission 
levels of hydrogen chloride and chlorine gas is achieving an emission 
level of 77 ppmv. Thus, MACT floor for existing sources is 77 ppmv.
    At proposal, we also defined floor control as wet scrubbing 
combined with feedrate control of chlorine. We proposed a floor 
emission level of 280 ppmv based on a chlorine feedrate control level 
of 21 g/dscm, expressed as a maximum theoretical emission 
concentration. The best performing sources relative to emission levels 
all use wet scrubbing and feed chlorine at that feedrate or lower. We 
identified a floor level of 280 ppmv based on all sources in our data 
base using floor control and after applying a statistically-derived 
emissions variability factor. In the May 1997 NODA, we again defined 
floor control as wet (or dry) scrubbing with feedrate control of 
chlorine. We discussed a floor emission level of 75 ppmv based on the 
revised data base and break-point floor methodology. Rather than using 
a break-point analysis in the final rule, we use a floor methodology 
that identifies floor control as an aggregate chlorine feedrate 
combined with scrubbing that achieves a removal efficiency of at least 
99 percent.
    We estimated compliance costs to the hazardous waste incinerator 
universe for administrative purposes. Approximately 70 percent of 
incinerators currently meet the hydrochloric acid and chlorine gas 
floor level of 77 ppmv. The annualized cost for the remaining 57 
incinerators to meet that level, assuming no market exits, is estimated 
to be $4.75 million and would reduce emissions of hydrochloric acid and 
chlorine gas nationally by 2,670 Mg per year from the baseline 
emissions level of 3410 Mg per year, a reduction of 78%.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? We considered more stringent beyond-the-floor controls to 
provide additional reduction in emissions. Due to the relatively low 
concentrations achieved at the floor, we determined that cost-
effectiveness considerations would likely be unacceptable. Therefore, 
we conclude that a beyond-the-floor standard for hydrochloric acid and 
chlorine gas for existing sources is not appropriate. We note that a 
beyond-the-floor standard is not needed to meet our RCRA protectiveness 
mandate.
    c. What Is the MACT Floor for New Sources? We identified a floor 
level of 280 ppmv at proposal based on the best performing source in 
the data base. That source uses wet scrubbing and a chlorine feedrate 
of 17 g/dscm, expressed as a maximum theoretical emission 
concentration. Our reevaluation of the revised data base in the May 
1997 NODA defined a floor level of 75 ppmv. Based on the aggregate 
feedrate approach used for today's final rule, we are establishing a 
floor level of 21 ppmv, based on a chlorine feedrate of 4.7 g/
dscm expressed as a maximum theoretical emission concentration.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? We 
considered more stringent beyond-the-floor controls to provide 
additional reduction in emissions. Due to the relatively low 
concentrations achieved at the floor, we determined that cost-
effectiveness considerations would likely be unacceptable. Therefore, 
we conclude that a beyond-the-floor standard for hydrochloric acid and 
chlorine gas for new sources is not appropriate. We note that a beyond-
the-floor standard is not needed to meet our RCRA protectiveness 
mandate.
8. What Are the Standards for Carbon Monoxide?
    We use carbon monoxide as a surrogate for organic hazardous air 
pollutants. Low carbon monoxide

[[Page 52869]]

concentrations in stack gas are an indicator of good control of organic 
hazardous air pollutants and are achieved by operating under good 
combustion practices.
    We establish carbon monoxide standards of 100 ppmv for both 
existing and new sources based on the rationale discussed below. 
Sources have the option to comply with either the carbon monoxide or 
the hydrocarbon emission standard. Sources that elect to comply with 
the carbon monoxide standard must also document compliance with the 
hydrocarbon standard during the performance test to ensure control of 
organic hazardous air pollutants. See discussion in Part Four, Section 
IV.B.
    a. What Is the MACT Floor for Existing Sources? As proposed, floor 
control for existing sources is operating under good combustion 
practices (e.g., providing adequate excess oxygen; providing adequate 
fuel (waste) and air mixing; maintaining high temperatures and adequate 
combustion gas residence time at those temperatures).102 
Given that there are many interdependent parameters that affect 
combustion efficiency and thus carbon monoxide emissions, we were not 
able to quantify ``good combustion practices.''
---------------------------------------------------------------------------

    \102\ USEPA, ``Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    We are identifying a floor level of 100 ppmv on an hourly rolling 
average, as proposed, because it is being achieved by sources using 
good combustion practices. More than 80 percent of test conditions in 
our data base have carbon monoxide levels below 100 ppmv, and more than 
60 percent have levels below 20 ppmv. Of approximately 20 test 
conditions with carbon monoxide levels exceeding 100 ppmv, we know the 
characteristics of many of these sources are not representative of good 
combustion practices (e.g., use of rotary kilns without afterburners; 
liquid injection incinerators with rapid combustion gas quenching). In 
addition, we currently limit carbon monoxide concentrations for 
hazardous waste burning boilers and industrial furnaces to 100 ppmv to 
ensure good combustion conditions and control of organic toxic 
compounds. Finally, we have established carbon monoxide limits in the 
range of 50 to 150 ppmv on other waste incineration sources (i.e., 
municipal waste combustors, medical waste incinerators) to ensure good 
combustion conditions. We are not aware of reasons why it may be more 
difficult for a hazardous waste incinerator to achieve carbon monoxide 
levels of 100 ppmv.
    We estimated compliance costs to the hazardous waste incinerator 
universe for administrative purposes. Because carbon monoxide emissions 
from these sources are already regulated under RCRA, approximately 97 
percent of incinerators currently meet the floor level of 100 ppmv. The 
annualized cost for the remaining six incinerators to meet the floor 
level, assuming no market exits, is estimated to be $0.9 million and 
would reduce carbon monoxide emissions nationally by 45 Mg per year 
from the baseline emissions level of 9170 Mg per year.103 
Although we cannot quantify a corresponding reduction of organic 
hazardous air pollutant emissions, we estimate these reductions would 
be significant based on the carbon monoxide reductions.
---------------------------------------------------------------------------

    \103\ As discussed previously in the text, you have the option 
of complying with the hydrocarbon emission standard rather than the 
carbon monoxide standard. This is because carbon monoxide is a 
conservative indicator of the potential for emissions of organic 
compounds while hydrocarbon concentrations in stack gas are a direct 
measure of emissions of organic compounds.
---------------------------------------------------------------------------

    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? We considered more stringent beyond-the-floor controls (i.e., 
better combustion practices resulting in lower carbon monoxide levels) 
to provide additional reduction in emissions. Although it is difficult 
to quantify the reduction in emissions of organic hazardous air 
pollutants that would be associated with a lower carbon monoxide limit, 
we concluded that cost-effectiveness considerations would likely come 
into play, and suggest that a beyond-the-floor standard is not 
warranted. Therefore, we conclude that a beyond-the-floor standard for 
carbon monoxide for existing sources is not appropriate. We note that, 
although control of carbon monoxide (or hydrocarbon) is not an absolute 
guarantee that nondioxin/furan products of incomplete combustion will 
not be emitted at levels of concern, this problem (where it may exist) 
can be addressed through the RCRA omnibus permitting process.
    c. What Is the MACT Floor for New Sources? At proposal and in the 
May 1997 NODA, we stated that operating under good combustion practices 
defines MACT floor control for new (and existing) 
sources,104 and the preponderance of data indicate that a 
floor level of 100 ppmv over an hourly rolling average is readily 
achievable. For reasons set forth in the proposal, and absent data to 
the contrary, we conclude that this floor level is appropriate.
---------------------------------------------------------------------------

    \104\ Because we cannot quantify good combustion practices, 
floor control for the single best controlled source is the same as 
for existing sources (i.e., that combination of design, operation, 
and maintenance that achieves good combustion as evidenced by carbon 
monoxide levels of 100 ppmv or less on an hourly rolling average).
---------------------------------------------------------------------------

    d. What Are Our Beyond-the-Floor Considerations for New Sources? We 
considered more stringent beyond-the-floor controls (i.e., better 
combustion practices resulting in lower carbon monoxide levels) to 
provide additional reduction in emissions. For the reasons discussed 
above in the context of beyond-the-floor controls for existing sources, 
however, we conclude that a beyond-the-floor standard for carbon 
monoxide for new sources is not appropriate.
9. What Are the Standards for Hydrocarbon?
    Hydrocarbon concentrations in stack gas are a direct surrogate for 
emissions of organic hazardous pollutants. We establish hydrocarbon 
standards of 10 ppmv for both existing and new sources based on the 
rationale discussed below. Sources have the option to comply with 
either the carbon monoxide or the hydrocarbon emission standard. 
Sources that elect to comply with the carbon monoxide standard, 
however, must nonetheless document compliance with the hydrocarbon 
standard during the comprehensive performance test.
    a. What Is the MACT Floor for Existing Sources? We proposed a 
hydrocarbon emission standard of 12 ppmv 105 based on good 
combustion practices, but revised it in the May 1997 NODA to 10 ppmv 
based on refinements of analysis and the corrected data base.
---------------------------------------------------------------------------

    \105\ Based on an hourly rolling average, reported as propane, 
corrected to 7 percent oxygen, dry basis.
---------------------------------------------------------------------------

    As proposed, floor control for existing sources is operating under 
good combustion practices (e.g., providing adequate excess oxygen; 
providing adequate fuel (waste) and air mixing; maintaining high 
temperatures and adequate combustion gas residence time at those 
temperatures). Given that there are many interdependent parameters that 
affect combustion efficiency and thus hydrocarbon emissions, we are not 
able to quantify good combustion practices.
    We are identifying a floor level for the final rule of 10 ppmv on 
an hourly rolling average because it is being achieved using good 
combustion practices. More than 85 percent of test conditions in our 
data base have hydrocarbon levels below 10 ppmv, and nearly 75 percent 
have levels below 5 ppmv. Although 13 test conditions in our data base 
representing 7 sources have hydrocarbon levels higher than 10 ppmv, we 
conclude that these sources

[[Page 52870]]

are not operating under good combustion practices. For example, one 
source is a rotary kiln without an afterburner. Another source is a 
fluidized bed type incinerator that operates at lower than typical 
combustion temperatures without an afterburner while another source is 
operating at high carbon monoxide levels, indicative of poor combustion 
efficiency.106
---------------------------------------------------------------------------

    \106\ USEPA, ``Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    Some commenters on the May 1997 NODA object to the 10 ppmv level 
and suggest adopting a level of 20 ppmv based on the BIF rule 
(Sec. 266.104(c)), and an earlier hazardous waste incinerator proposal 
(55 FR 17862 (April 27, 1990)). These commenters cite sufficient 
protectiveness at the 20 ppmv level. We conclude that this comment is 
not on point because the MACT standards are technology rather than 
risk-based. The MACT standards must reflect the level of control that 
is not less stringent than the level of control achieved by the best 
performing sources. Because hazardous waste incinerators are readily 
achieving a hydrocarbon level of 10 ppmv using good combustion 
practices, that floor level is appropriate.
    Some commenters also object to the requirement to use heated flame 
ionization hydrocarbon detectors 107 in hazardous waste 
incinerators that use wet scrubbers. The commenters state that these 
sources have a very high moisture content in the flue gas that hinders 
proper functioning of the specified hydrocarbon detectors. We agree 
that hydrocarbon monitors may be hindered in these situations. For this 
and other reasons (e.g., some sources can have high carbon monoxide but 
low hydrocarbon levels), the final rule gives sources the option of: 
(1) Continuous hydrocarbon monitoring; or (2) continuous carbon 
monoxide monitoring and demonstration of compliance with the 
hydrocarbon standard only during the performance test.
---------------------------------------------------------------------------

    \107\ See Performance Specification 8A, appendix B, part 60, 
``Specifications and test procedures for carbon monoxide and oxygen 
continuous monitoring systems in stationary sources.''
---------------------------------------------------------------------------

    We estimated compliance costs to the hazardous waste incinerator 
universe for administrative purposes. Approximately 97 percent of 
incinerators currently meet the hydrocarbon floor level of 10 ppmv. The 
annualized cost for the remaining six incinerators to meet the floor 
level, assuming no market exits, is estimated to be $0.35 million, and 
would reduce hydrocarbon emissions nationally by 28 Mg per year from 
the baseline emissions level of 292 Mg per year. Although the 
corresponding reduction of organic hazardous air pollutant emissions 
cannot be quantified, these reductions are qualitatively assessed as 
significant.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? We considered more stringent beyond-the-floor controls (i.e., 
better combustion practices resulting in lower hydrocarbon levels) to 
provide additional reduction in emissions. Although it is difficult to 
quantify the reduction in emissions of organic hazardous air pollutants 
that would be associated with a lower hydrocarbon limit, cost-
effectiveness considerations would likely come into play, however, and 
suggest that a beyond-the-floor standard is not warranted. Therefore, 
we conclude that a beyond-the-floor standard for hydrocarbon emissions 
for existing sources is not appropriate. We note further that, although 
control of hydrocarbon emissions is not an absolute guarantee that 
nondioxin products of incomplete combustion will not be emitted at 
levels of concern, this problem (where it may exist) can be addressed 
through the RCRA omnibus permitting process.
    c. What Is the MACT Floor for New Sources? At proposal and in the 
May 1997 NODA, we stated that operation under good combustion practices 
at new (and existing) hazardous waste incinerators defines the MACT 
control.108 As discussed above, sources using good 
combustion practices are achieving hydrocarbon levels of 10 ppmv or 
below. Comments on this subject were minor and did not identify any 
problems in achieving the 10 ppmv level by new sources. Thus, we 
conclude that a floor level of 10 ppmv on hourly rolling average is 
appropriate for new sources.
---------------------------------------------------------------------------

    \108\ Because we cannot quantify good combustion practices, 
floor control for the single best controlled soruce is the same as 
for existing sources (i.e., that combination of design, operation, 
and maintenance that achieves good combustion as evidenced by 
hydrocarbon levels of 10 ppmv or less on an hourly rolling average).
---------------------------------------------------------------------------

    d. What Are Beyond-the-Floor Considerations for New Sources? We 
considered more stringent beyond-the-floor controls (i.e., better 
combustion practices) to provide additional reduction in emissions. For 
the reasons discussed above in the context of beyond-the-floor controls 
for existing sources, however, we conclude that a beyond-the-floor 
standard for hydrocarbons for new sources is not appropriate.
10. What Are the Standards for Destruction and Removal Efficiency?
    We establish a destruction and removal efficiency (DRE) standard 
for existing and new incinerators to control emissions of organic 
hazardous air pollutants other than dioxins and furans. Dioxins and 
furans are controlled by separate emission standards. See discussion in 
Part Four, Section IV.A. The DRE standard is necessary, as previously 
discussed, to complement the carbon monoxide and hydrocarbon emission 
standards, which also control these hazardous air pollutants.
    The standard requires 99.99 percent DRE for each principal organic 
hazardous constituent (POHC), except that 99.9999 percent DRE is 
required if specified dioxin-listed hazardous wastes are burned. These 
wastes are listed as--F020, F021, F022, F023, F026, and F027--RCRA 
hazardous wastes under Part 261 because they contain high 
concentrations of dioxins.
    a. What Is the MACT Floor for Existing Sources? Existing sources 
are currently subject to DRE standards under Sec. 264.342 and 
Sec. 264.343(a) that require 99.99 percent DRE for each POHC, except 
that 99.9999 percent DRE is required if specified dioxin-listed 
hazardous wastes are burned. Accordingly, these standards represent 
MACT floor. Since all hazardous waste incinerators are currently 
subject to these DRE standards, they represent floor control, i.e., 
greater than 12 percent of existing sources are achieving these 
controls.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? Beyond-the-floor control would be a requirement to achieve a 
higher percentage DRE, for example, 99.9999 percent DRE for POHCs for 
all hazardous wastes. A higher DRE could be achieved by improving the 
design, operation, or maintenance of the combustion system to achieve 
greater combustion efficiency.
    Sources will not incur costs to achieve the 99.99 percent DRE floor 
because it is an existing RCRA standard. A substantial number of 
existing incinerators are not likely to be routinely achieving 99.999 
percent DRE, however, and most are not likely to be achieving 99.9999 
percent DRE. Improvements in combustion efficiency will be required to 
meet these beyond-the-floor DREs. Improved combustion efficiency is 
accomplished through better mixing, higher temperatures, and longer 
residence times. As a practical matter, most combustors are mixing-
limited. Thus, improved mixing is

[[Page 52871]]

necessary for improved DREs. For a less-than-optimum burner, a certain 
amount of improvement may typically be accomplished by minor, 
relatively inexpensive combustor modifications--burner tuning 
operations such as a change in burner angle or an adjustment of swirl--
to enhance mixing on the macro-scale. To achieve higher and higher 
DREs, however, improved mixing on the micro-scale may be necessary 
requiring significant, energy intensive and expensive modifications 
such as burner redesign and higher combustion air pressures. In 
addition, measurement of such DREs may require increased spiking of 
POHCs and more sensitive stack sampling and analysis methods at added 
expense.
    Although we have not quantified the cost-effectiveness of a beyond-
the-floor DRE standard, we do not believe that it would be cost-
effective. For reasons discussed above, we believe that the cost of 
achieving each successive order-of-magnitude improvement in DRE will be 
at least constant, and more likely increasing. Emissions reductions 
diminish substantially, however, with each order of magnitude 
improvement in DRE. For example, if a source were to emit 100 gm/hr of 
organic hazardous air pollutants assuming zero DRE, it would emit 10 
gm/hr at 90 percent DRE, 1 gm/hr at 99 percent DRE, 0.1 gm/hr at 99.9 
percent DRE, 0.01 gm/hr at 99.99 percent DRE, and 0.001 gm/hr at 99.999 
percent DRE. If the cost to achieve each order of magnitude improvement 
in DRE is roughly constant, the cost-effectiveness of DRE decreases 
with each order of magnitude improvement in DRE. Consequently, we 
conclude that this relationship between compliance cost and diminished 
emissions reductions associated with a more stringent DRE standard 
suggests that a beyond-the-floor standard is not warranted.
    c. What Is the MACT Floor for New Sources? The single best 
controlled source, and all other hazardous waste incinerators, are 
subject to the existing RCRA DRE standard under Sec. 264.342 and 
Sec. 264.343(a). Accordingly, we adopt this standard as the MACT floor 
for new sources.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? As 
discussed above, although we have not quantified the cost-effectiveness 
of a more stringent DRE standard, diminishing emissions reductions with 
each order of magnitude improvement in DRE suggests that cost-
effectiveness considerations would likely come into play. We conclude 
that a beyond-the-floor standard is not warranted.

VII. What Are the Standards for Hazardous Waste Burning Cement Kilns?

A. To Which Cement Kilns Do Today's Standards Apply?
    The standards promulgated today apply to each existing, 
reconstructed, and newly constructed Portland cement manufacturing kiln 
that burns hazardous waste. These standards apply to all hazardous 
waste burning cement kilns (both major source and area source cement 
plants). Portland cement kilns that do not engage in hazardous waste 
burning operations are not subject to this NESHAP. However, these 
hazardous waste burning kilns would be subject to the NESHAP for other 
sources of hazardous air pollutants at the facility (e.g., clinker 
cooler stack) that we finalized in June 1999.109
---------------------------------------------------------------------------

    \109\ On June 14, 1999, we promulgated regulations for kiln 
stack emissions for nonhazardous waste burning cement kilns and 
other sources of hazardous air pollutants at all Portland 
manufacturing plants. (See 64 FR 31898.)
---------------------------------------------------------------------------

B. How Did EPA Initially Classify Cement Kilns?
1. What Is the Basis for a Separate Class Based on Hazardous Waste 
Burning?
    Portland cement manufacturing is one of the initial 174 categories 
of major and area sources of hazardous air pollutants listed pursuant 
to section 112(c)(1) for which section 112(d) standards are to be 
established.110 We divided the Portland cement manufacturing 
source category into two different classes based on whether the cement 
kiln combusts hazardous waste. This action was taken for two principal 
reasons: If hazardous wastes are burned in the kiln, emissions of 
hazardous air pollutants can be different for the two types of kilns in 
terms of both types and concentrations of hazardous air pollutants 
emitted, and metals and chlorine emissions are controlled in a 
significantly different manner.
---------------------------------------------------------------------------

    \110\ EPA published an initial list of 174 categories of area 
and major sources in the Federal Register on July 16, 1992. (See 57 
FR at 31576.)
---------------------------------------------------------------------------

    A comparison of metals levels in coal and in hazardous waste fuel 
burned in lieu of coal on a heat input basis reveals that hazardous 
waste frequently contains higher concentrations of hazardous air 
pollutant metals (i.e., mercury, semivolatile metals, low volatile 
metals) than coal. Hazardous waste contains higher levels of 
semivolatile metals than coal by more than an order of magnitude at 
every cement kiln in our data base.111 In addition, coal 
concentrations of mercury and low volatile metals were less than 
hazardous waste by approximately an order of magnitude at every 
facility except one. Thus, a cement kiln feeding a hazardous waste fuel 
is likely to emit more metal hazardous air pollutants than a 
nonhazardous waste burning cement kiln. Given this difference in 
emissions characteristics, we divided the Portland cement manufacturing 
source category into two classes based on whether hazardous waste is 
burned in the cement kiln.
---------------------------------------------------------------------------

    \111\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    Today's rule does not establish hazardous air pollutant emissions 
limits for other hazardous air pollutant-emitting sources at a 
hazardous waste burning cement plant. These other sources of hazardous 
air pollutants may include materials handling operations, conveyor 
system transfer points, raw material dryers, and clinker coolers. 
Emissions from these sources are subject to the requirements 
promulgated in the June 14, 1999 Portland cement manufacturing NESHAP. 
See 64 FR 31898. These standards are applicable to these other sources 
of hazardous air pollutants at all Portland cement plants, both for 
nonhazardous waste burners and hazardous waste burners.
    In addition, this regulation does not establish standards for 
cement kiln dust management facilities (e.g., cement kiln dust piles or 
landfills). We are developing cement kiln dust storage and disposal 
requirements in a separate rulemaking.
2. What Is the Basis for Differences in Standards for Hazardous Waste 
and Nonhazardous Waste Burning Cement Kilns?
    Today's final standards for hazardous waste burning cement kilns 
are identical in some respects to those finalized for nonhazardous 
waste burning cement kilns on June 14, 1999. The standards differ, 
however, in several important aspects. A comparison of the major 
features of the two sets of standards and the basis for major 
differences is discussed below.
    a. How Does the Regulation of Area Sources Differ? As discussed 
earlier, this rule makes a positive area source finding under section 
112(c)(3) of the CAA (i.e., a finding that hazardous air pollutant 
emissions from an area source can pose potential risk to human health 
and the environment) for existing hazardous waste burning cement kilns 
and subjects area sources to the same standards that apply to major 
sources. (See Part Three, Section III.B of today's preamble.) For 
nonhazardous waste burning cement kilns, however, we regulate area 
sources under authority of

[[Page 52872]]

section 112(c)(6) of the CAA, and so apply MACT standards only to the 
section 112(c)(6) hazardous air pollutants emitted from such sources.
    The positive finding for hazardous waste burning cement kilns is 
based on several factors and, in particular, on concern about potential 
health risk from emissions of mercury and nondioxin/furan organic 
hazardous air pollutants which are products of incomplete combustion.
    However, we do not have this same level of concern with hazardous 
air pollutant emissions from nonhazardous waste burning cement kilns 
located at area source cement plants, and so did not make a positive 
area source finding. As discussed above, mercury emissions from 
hazardous waste burning cement kilns are generally higher than those 
from nonhazardous waste burning cement kilns. Also, nondioxin and 
nonfuran organic hazardous air pollutants emitted from hazardous waste 
burning cement kilns have the potential to be greater than those from 
nonhazardous waste burning cement kilns because hazardous waste can 
contain high concentrations of a wide-variety of organic hazardous air 
pollutants. In addition, some hazardous waste burning cement kilns feed 
containers of hazardous waste at locations (e.g., midkiln, raw material 
end of the kiln) other than the normal coal combustion zone. If such 
firing systems are poorly designed, operated, or maintained, emissions 
of nondioxin and furan organic hazardous air pollutants could be 
substantial (and, again, significantly greater than comparable 
emissions from nonhazardous waste Portland cement plants). Finally, 
hazardous air pollutant emissions from nonhazardous waste burning 
cement kilns currently are not regulated uniformly under another 
statute as is the case for hazardous waste burning cement kilns which 
affects which pollutants are controlled at the floor for each class.
    Under the June 1999 final rule, existing and new nonhazardous waste 
burning cement kilns at area source plants are subject to dioxin and 
furan emission standards, and a hydrocarbon 112 standard for 
new nonhazardous waste burning cement kilns that are area sources. 
These standards are promulgated under the authority of section 
112(c)(6). That section requires the Agency to establish MACT standards 
for source categories contributing significantly in the aggregate to 
emissions of identified, particularly hazardous air pollutants. The 
MACT process was also applied to the control of mercury, although the 
result was a standard of no control.
---------------------------------------------------------------------------

    \112\ Hydrocarbon emissions would be limited as a surrogate for 
polycyclic organic matter, a category of organic hazardous air 
pollutants identified in section 112(c)(6).
---------------------------------------------------------------------------

    b. How Do the Emission Standards Differ? The dioxin, furan and 
particulate matter emission standards for nonhazardous waste burning 
cement kilns are identical to today's final standard for hazardous 
waste burning cement kilns. The standards for both classes of kilns are 
floor standards and are identical because hazardous waste burning is 
not likely to affect emissions of either dioxin/furan 113 or 
particulate matter. We also conclude that beyond-the-floor standards 
for these pollutants would not be cost-effective for either class of 
cement kilns.
---------------------------------------------------------------------------

    \113\ Later in the text, however, we discuss how hazardous waste 
burning may potentially affect dioxin and furan emissions and the 
additional requirements for hazardous waste burning cement kilns 
that address this concern.
---------------------------------------------------------------------------

    Under today's rule, hazardous waste burning cement kilns are 
subject to emission standards for mercury, semivolatile metals, low 
volatile metals, and hydrochloric acid/chlorine gas, but we did not 
finalize such standards for nonhazardous waste burning cement kilns. 
Currently, emissions of these hazardous air pollutants from hazardous 
waste burning cement kilns are regulated under RCRA. Therefore, we 
could establish floor levels for each pollutant under the CAA. These 
hazardous air pollutants, however, currently are not controlled for 
nonhazardous waste burning cement kilns and floor levels would be 
uncontrolled levels (i.e., the highest emissions currently 
achieved).114 We considered beyond-the-floor controls and 
emission standards for mercury and hydrochloric acid for nonhazardous 
waste burning cement kilns, but conclude that beyond-the-floor 
standards are not cost-effective, especially considering the lower 
rates of current emissions for nonhazardous waste burning plants.
---------------------------------------------------------------------------

    \114\ Although semivolatile metal and low volatile metal are 
controlled by nonhazardous waste burning cement kilns, along with 
other metallic hazardous air pollutants, by controlling particulate 
matter. These metals are not individually controlled by nonhazardous 
waste burning cement kilns as they are for hazardous waste burning 
cement kilns by virtue of individual metal feedrate limits 
established under existing RCRA regulations.
---------------------------------------------------------------------------

    Finally, under today's rule, hazardous waste burning cement kilns 
are subject to emission limits on carbon monoxide and hydrocarbon and a 
destruction and removal efficiency standard to control nondioxin/furan 
organic hazardous air pollutants. We identified these controls as floor 
controls because carbon monoxide and hydrocarbon emissions are 
controlled for these sources under RCRA regulations, as is destruction 
and removal efficiency.115 For nonhazardous waste burning 
cement kilns, carbon monoxide and hydrocarbon emissions currently are 
not controlled, and the destruction and removal efficiency standard, 
established under RCRA, does not apply. Therefore, carbon monoxide, 
hydrocarbon control and the destruction and removal efficiency standard 
are not floor controls for this second group of cement kilns. We 
considered beyond-the-floor controls for hydrocarbon from nonhazardous 
waste burning cement kilns and determined that beyond-the-floor 
controls for existing sources are not cost-effective. The basis of this 
conclusion is discussed in the proposed rule for nonhazardous waste 
burning cement kilns (see 63 FR at 14202). We proposed and finalized, 
however, a hydrocarbon emission standard for new source nonhazardous 
waste cement kilns based on feeding raw materials without an excessive 
organic content.116 See 63 FR at 14202 and 64 FR 31898.
---------------------------------------------------------------------------

    \115\ For hazardous waste burning cement kilns, existing RCRA 
carbon monoxide and hydrocarbon standards do not apply to the main 
stack of a kiln equipped with a by-pass or other means of measuring 
carbon monoxide or hydrocarbon at mid kiln to ensure good combustion 
of hazardous waste. Therefore, there is no carbon monoxide or 
hydrocarbon floor control for such stacks, and we conclude that 
beyond-the-floor controls would not be cost-effective.
    \116\ Consistent with the nonhazardous waste burnign cement kiln 
proposal, however, we subject the main stack of such new source 
hazardous waste burning cemen tkilns to a hydrocarbon standard.
---------------------------------------------------------------------------

    We did not consider a destruction and removal efficiency standard 
as a beyond-the-floor control for nonhazardous waste burning cement 
kilns because, based historically on a unique RCRA statutory provision, 
the DRE standard is designed to ensure destruction of organic hazardous 
air pollutants in hazardous waste fed to hazardous waste combustors. 
The underlying rationale for such a standard is absent for nonhazardous 
waste burning cement kilns that do not combust hazardous waste and that 
feed materials (e.g., limestone, coal) that contain only incidental 
levels of organic hazardous air pollutants.
    c. How Do the Compliance Procedures Differ? We finalized compliance 
procedures for nonhazardous waste burning cement kilns that are similar 
to those finalized today for hazardous waste burning cement kilns. For 
particulate matter, we are implementing a coordinated program to 
document the feasibility of particulate matter continuous emissions 
monitoring

[[Page 52873]]

systems on both nonhazardous waste and hazardous waste burning cement 
kilns. We plan to establish a continuous emissions monitoring systems-
based emission level through future rulemaking that is achievable by 
sources equipped with MACT control (i.e., an electrostatic precipitator 
or fabric filter designed, operated, and maintained to meet the New 
Source Performance Standard particulate matter standard). In the 
interim, we use the opacity standard as required by the New Source 
Performance Standard for Portland cement plants under Sec. 60.62 to 
ensure compliance with the particulate matter standard for both 
hazardous waste and nonhazardous waste burning cement kilns.
    For dioxin/furan, the key compliance parameter will be identical 
for both hazardous waste and nonhazardous waste burning cement kilns--
control of temperature at the inlet to the particulate matter control 
device. Other factors that could contribute to the formation of dioxins 
and furans, however, are not completely understood. As a result, 
hazardous waste burning cement kilns have additional compliance 
requirements to ensure that hazardous waste is burned under good 
combustion conditions. These additional controls are necessary because 
of the dioxin and furan precursors that can be formed from improper 
combustion of hazardous waste, given the hazardous waste firing systems 
used by some hazardous waste burning cement kilns and the potential for 
hazardous waste to contain high concentrations of many organic 
hazardous air pollutants not found in conventional fuels or cement kiln 
raw materials.
    We also require both hazardous waste and nonhazardous waste burning 
cement kilns to conduct performance testing midway between the five-
year periodic comprehensive performance testing to confirm that dioxin/
furan emissions do not exceed the standard when the source operates 
under normal conditions.
C. What Further Subcategorization Considerations Are Made?
    We also fully considered further subdividing the class of hazardous 
waste burning cement kilns itself. For the reasons discussed below, we 
decided that subcategorization is not needed to determine achievable 
MACT standards for all hazardous waste burning cement kilns.
    We considered, but rejected, subdividing the hazardous waste 
burning cement kiln source category on the basis of raw material feed 
preparation, more specifically wet process versus dry process. In the 
wet process, raw materials are ground, wetted, and fed into the kiln as 
a slurry. Approximately 70 percent of the hazardous waste burning 
cement kilns in operation use a wet process. In the dry process, raw 
materials are ground dry and fed into the kiln dry. Within the dry 
process there are three variations: Long kiln dry process, preheater 
process, and preheater-precalciner process. We decided not to 
subcategorize the hazardous waste burning cement kiln category based on 
raw material feed preparation because: (1) The wet process kilns and 
all variations of the dry process kilns use similar raw materials, 
fossil fuels, and hazardous waste fuels; (2) the types and 
concentrations of uncontrolled hazardous air pollutant emissions are 
similar for both process types;117 (3) the same types of 
particulate matter pollution control equipment, specifically either 
fabric filters or electrostatic precipitators, are used by both process 
types, and the devices achieve the same level of performance when used 
by both process types; and (4) the MACT controls we identify are 
applicable to both process types of cement kilns. For example, MACT 
floor controls for metals and chlorine include good particulate matter 
control and hazardous waste feedrate control, as discussed below, the 
particulate matter standard promulgated today is based on the New 
Source Performance Standard, which applies to all cement kilns 
irrespective of process type. Further, a cement kiln operator has great 
discretion in the types of hazardous waste they accept including the 
content of metals and chlorine in the waste. These basic control 
techniques--particulate matter control and feedrate control of metals 
and chlorine--clearly show that subcategorization based on process type 
is not appropriate.
---------------------------------------------------------------------------

    \117\ Although dry process kilns with a separate by-pass stack 
can have higher metals emissions from that stack compared to the 
main stack of other kilns, today's rule allows such kilns to 
flowrate-average its emissions between the main and by-pass stack. 
The average emissions are similar to the emissions from dry and wet 
kilns that have only one stack. Similarly, kilns with in-line raw 
mills have higher mercury emissions when the raw mill is off. 
Today's rule allows such kilns to time-weight average their 
emissions, however, and the time-weighted emissions for those kilns 
are similar to emissions from other hazardous waste burning cement 
kilns.
---------------------------------------------------------------------------

    Some commenters stated that it is not feasible for wet process 
cement kilns to use fabric filters, especially in cold climates, and 
thus subcategorization based on process type is appropriate. The 
problem, commenters contend, is that the high moisture content of the 
flue gas will clog the fabric if the cement-like particulate is wetted 
and subsequently dried, resulting in reduced performance and early 
replacement of the fabric filter bags. Other commenters disagreed with 
these assertions and stated that fabric filter technology can be 
readily applied to wet process kilns given the exit temperatures of the 
combustion gases and the ease of insulating fabric filter systems to 
minimize cold spots in the baghouse to avoid dew point problems and 
minimize corrosion. These commenters pointed to numerous wet process 
applications currently in use at cement kilns with fabric filter 
systems located in cold climates to support their claims.118 
In light of the number of wet process kilns already using fabric 
filters and their various locations, we conclude that wet process 
cement kilns can be equipped with fabric filter systems and that 
subdividing by process type on this basis is not necessary or 
warranted. A review of the particulate matter emissions data for one 
wet hazardous waste burning cement kiln using a fabric filter shows 
that it is achieving the particulate matter standard. We do not have 
data in our data base from the only other wet hazardous waste burning 
cement kiln using a fabric filter; however, this cement kiln recently 
installed and upgraded to a new fabric filter system.
---------------------------------------------------------------------------

    \118\ We are aware of four wet process cement kiln facilities 
operating with fabric filters: Dragon (Thomaston, ME), Giant 
(Harleyville, SC), Holnam (Dundee, MI), and LaFarge (Paulding, OH). 
Commenters also identified kilns in Canada operating with fabric 
filters.
---------------------------------------------------------------------------

    We also fully considered, but ultimately rejected, subdividing the 
hazardous waste burning cement kiln source category between long kilns 
and short kilns (preheater and preheater-precalciner) technologies, and 
those with in-line kiln raw mills. This subcategorization approach was 
recommended by many individual cement manufacturing member companies 
and a cement manufacturing trade organization. Based on information on 
the types of cement kilns that are currently burning hazardous waste, 
these three subcategories consist of the following four subdivisions: 
(1) Short kilns with separate by-pass and main stacks; (2) short kilns 
with a single stack that handles both by-pass and preheater or 
precalciner emissions; (3) long dry kilns that use kiln gas to dry raw 
meal in the raw mill; and (4) others wet kilns, and long dry kilns not 
using in-line kiln raw mill drying. Currently, each of the first three 
categories consists of only one cement kiln facility while

[[Page 52874]]

the kilns at the remaining 15 facilities are in the fourth category: 
wet kilns or long dry kilns that do not use in-line kiln raw mill 
drying.
    Commenters state that these subcategories should be considered 
because the unique design or operating features of the different types 
of kilns could have a significant impact on emissions of one or more 
hazardous air pollutants that we proposed to regulate. Specifically, 
commenters noted the potential flue gas characteristic differences for 
cement kilns using alkali bypasses on short kilns and in-line kiln raw 
mills. For example, kilns with alkali bypasses are designed to divert a 
portion of the flue gas, approximately 10-30%, to remove the 
problematic alkalis, such as potassium and sodium oxides, that can 
react with other compounds in the cool end of the kiln resulting in 
operation problems. Thus, bypasses allow evacuation of the undesirable 
alkali metals and salts, including semivolatile metals and chlorides, 
entrained in the kiln exit gases before they reach the preheater 
cyclones. As a result, the commenters stated that the emission 
concentration of semivolatile metals in the bypass stack is greater 
than in the main stack, and therefore the difference in emissions 
supports subcategorization.
    We agree, in theory, that the emissions profile for some hazardous 
air pollutants can be different for the three kilns types--short kilns 
with and without separate bypass stacks, long kilns with in-line kiln 
raw mills. To consider this issue further, we analyzed floor control 
and floor emissions levels based only on the data and information from 
the other long wet kilns and long dry kilns not using raw mill drying. 
We then considered whether the remaining three kiln types could apply 
the same MACT controls and achieve the resulting emission standards. We 
conclude that these three types of kilns at issue can use the MACT 
controls and achieve the corresponding emission levels identified in 
today's rule for the wet kilns and long dry kilns not using raw mill 
drying.119 As a result, we conclude that there is no 
practical necessity driving a subcategorization approach even though 
one would be theoretically possible. Further, to ensure that today's 
standards are achievable by all cement kilns, we establish a provision 
that allows cement kilns operating in-line kiln raw mills to average 
their emissions based on a time-weighted average concentration that 
considers the length of time the in-line raw mill is on-line and off 
line. We also adopt a provision that allows short cement kilns with 
dual stacks to average emissions on a flow-weighted basis to 
demonstrate compliance with the emissions standards. (See Part Five, 
Section X--Special Provisions for a discussion of these provisions.)
---------------------------------------------------------------------------

    \119\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    In the case of hydrocarbons and carbon monoxide, we developed final 
standards that reflect the concerns raised by several commenters. We 
determined that this approach best accommodated the unique design and 
operating differences between long wet and long dry process and short 
kilns using either a preheater or a preheater and precalciner.
    Existing hazardous waste preheater and preheater-precalciner cement 
kilns, one of each type is burning hazardous waste, are equipped with 
bypass ducts that divert a portion of the kiln off-gas through a 
separate particulate matter control device to remove problematic alkali 
metals. Long cement kilns do not use bypasses designed to remove alkali 
metals. The significance of this operational difference is that 
hydrocarbon and carbon monoxide levels in the bypass gas of short kilns 
is more representative of the combustion efficiency of burning 
hazardous waste and other fuels in the kiln than the measurements made 
in the main stack. Main stack gas measurements of hydrocarbons and 
carbon monoxide, regardless of process type, also include contributions 
from trace levels of organic matter volatilized from the raw materials, 
which can mask the level of combustion efficiency achieved in the kiln.
    Today's tailored standards require cement kilns to monitor 
hydrocarbons and carbon monoxide at the location best indicative of 
good combustion. For short kilns with bypasses, the final rule requires 
monitoring of hydrocarbons and carbon monoxide in the bypass. Long 
kilns are required to comply with the hydrocarbon and carbon monoxide 
standards in the main stack. However, long kilns that operate a mid-
kiln sampling system, for the purpose of removing a representative 
portion of the kiln off-gas to measure combustion efficiency, can 
comply with the hydrocarbon and carbon monoxide standards at the 
midkiln sampling point.
    In addition, establishing separate hydrocarbon and carbon monoxide 
standards reflects the long and short kiln subcategorization approach 
recommended by some commenters. The standards differ because MACT floor 
control for hydrocarbons and carbon monoxide is based primarily on the 
existing requirements of the Boiler and Industrial Furnace rule. In 
that rule, the unique design and operating features of long and short 
kilns were considered in establishing type specific emission limits for 
hydrocarbons and carbon monoxide. Thus, MACT floor control for long and 
short kilns is different. However, we note these same unique design and 
operating features were not a factor in establishing standards for 
other pollutants, including mercury, semivolatile and low volatile 
metals, and hydrochloric acid/chlorine gas, in the Boiler and 
Industrial Furnace rule.
    For the reasons discussed above, subcategorization would not appear 
to be needed to establish uniform, achievable MACT standards for all 
cement kilns burning hazardous waste. Thus, because the differences 
among kiln types ``does not affect the feasibility and effectiveness of 
air pollution control technology,'' subcategorization is not 
appropriate. S. Rep. No. 228, 101st Cong. 1st sess. 166.
D. What Are The Standards for Existing and New Cement Kilns?
1. What Are the Standards for Cement Kilns?
    In this section, the basis for the emissions standards for cement 
kilns is discussed. The kiln emission limits apply to the kiln stack 
gases, in-line kiln raw mill stack gases if combustion gases pass 
through the in-line raw mill, and kiln alkali bypass stack gases if 
discharged through a separate stack from cement plants that burn 
hazardous waste in the kiln. The emissions standards are summarized 
below:

[[Page 52875]]



               Standards for Existing and New Cement Kilns
------------------------------------------------------------------------
 Hazardous air pollutant or              Emissions standard 1
   hazardous air pollutant   -------------------------------------------
          surrogate             Existing sources         New sources
------------------------------------------------------------------------
Dioxin and furan............  0.20 ng TEQ/dscm; or  0.20 ng TEQ/dscm; or
                               0.40 ng TEQ/dscm      0.40 ng TEQ/dscm
                               and control of flue   and control of flue
                               gas temperature not   gas temperature not
                               to exceed 400 deg.F   to exceed 400 deg.F
                               at the inlet to the   at the inlet to the
                               particulate matter    particulate matter
                               control device.       control device.
Mercury.....................  120 g/dscm.  56 g/dscm.
Particulate matter 2........  0.15 kg/Mg dry feed   0.15 kg/Mg dry feed
                               and 20% opacity.      and 20% opacity.
Semivolatile metals.........  240 g/dscm.  180 g/dscm.
Low volatile metals.........  56 g/dscm..  54 g/dscm.
Hydrochloric acid and         130 ppmv............  86 ppmv.
 chlorine gas.
Hydrocarbons: kilns without   20 ppmv (or 100 ppmv  Greenfield kilns: 20
 by-pass 3, 6.                 carbon monoxide) 3.   ppmv (or 100 ppmv
                                                     carbon monoxide and
                                                     50 ppmv 5
                                                     hydrocarbons).
                              ....................  All others: 20 ppmv
                                                     (or 100 ppmv carbon
                                                     monoxide) 3.
Hydrocarbons: kilns with by-  No main stack         50 ppmv 5.
 pass; main stack 4, 6.        standard.
Hydrocarbons: kilns with by-  10 ppmv (or 100 ppmv  10 ppmv (or 100 ppmv
 pass; by-pass duct and        carbon monoxide).     carbon monoxide).
 stack 3, 4, 6.
Destruction and removal        For existing and new sources, 99.99% for
 efficiency.                        each principal organic hazardous
                                   constituent (POHC) designated. For
                                 sources burning hazardous wastes F020,
                               F021, F022, F023, F026, or F027, 99.9999%
                                       for each POHC designated.
------------------------------------------------------------------------
\1\ All emission levels are corrected to 7% O2, dry basis.
\2\ If there is an alkali by-pass stack associated with the kiln or in-
  line kiln raw mill, the combined particulate matter emissions from the
  kiln or in-line kiln raw mill and the alkali by-pass must be less than
  the particulate matter emissions standard.
\3\ Cement kilns that elect to comply with the carbon monoxide standard
  must demonstrate compliance with the hydrocarbon standard during the
  comprehensive performance test.
\4\ Measurement made in the by-pass sampling system of any kiln (e.g.,
  alkali by-pass of a preheater and/or precalciner kiln; midkiln
  sampling system of a long kiln).
\5\ Applicable only to newly-constructed cement kilns at greenfield
  sites (see discussion in Part Four, Section VII.D.9). 50 ppmv standard
  is a 30-day block average limit. Hydrocarbons reported as propane.
\6\ Hourly rolling average. Hydrocarbons are reported as propane.

2. What Are the Dioxin and Furan Standards?
    In today's rule, we establish a standard for new and existing 
cement kilns that limits dioxin/furan emissions to either 0.20 ng TEQ/
dscm; or 0.40 ng TEQ/dscm and temperature at the inlet to the 
particulate matter control device not to exceed 
400 deg.F.120 Our rationale for these standards is discussed 
below.
---------------------------------------------------------------------------

    \120\ The temperature limit applies at the inlet to a dry 
particulate matter control device that suspends particulate matter 
in the combustion gas stream (e.g., electrostatic precipitator, 
fabric filter) such that surface-catalyzed formation of dioxin/furan 
is enhanced. The temperature limit does not apply to a cyclone 
control device, for example.
---------------------------------------------------------------------------

    a. What Is the MACT Floor for Existing Sources? In the April 1996 
proposal, we identified floor control as either temperature control at 
the inlet to the particulate matter control device of less than 
418 deg.F, or achieving a specific level of dioxin/furan emissions 
based upon levels achievable using proper temperature control. (61 FR 
at 17391.) The proposed floor emission level was 0.20 ng TEQ/dscm, or 
temperature at the inlet to the electrostatic precipitator or fabric 
filter not to exceed 418 deg.F. In the May 1997 NODA, we identified an 
alternative data analysis method to identify floor control and the 
floor emission level. Floor control for dioxin/furan was defined as 
temperature control at the inlet to the electrostatic precipitator or 
fabric filter at 400 deg.F, which was based on further engineering 
evaluation of the emissions data and other available information. That 
analysis resulted in a floor emission level of 0.20 ng TEQ/dscm, or 
0.40 ng TEQ/dscm and temperature at the inlet to the electrostatic 
precipitator or fabric filter not to exceed 400 deg.F. (62 FR at 
24226.) The 0.40 ng TEQ/dscm standard is the level that all cement 
kilns, including data from nonhazardous waste burning cement kilns, are 
achieving when operating at the MACT floor control level or better. We 
considered a data set that included dioxin/furan emissions from 
nonhazardous waste burning cement kilns because these data are 
adequately representative of general dioxin/furan behavior and control 
in either type of kiln. The impacts of hazardous waste constituents 
(HAPs) on the emissions of those HAPs prevent us from expanding our 
database for other HAPs in a similar way.
    We conclude that the floor methodology discussed in the May 1997 
NODA is appropriate and we adopt this approach in today's final rule. 
We identified two technologies for control of dioxin/furan emissions 
from cement kilns in the May 1997 NODA. The first technology achieves 
low dioxin/furan emissions by quenching kiln gas temperatures at the 
exit of the kiln so that gas temperatures at the inlet to the 
particulate matter control device are below the temperature range of 
optimum dioxin/furan formation. For example, we are aware of several 
cement kilns that have recently added flue gas quenching units upstream 
of the particulate matter control device to reduce the inlet 
particulate matter control device temperature resulting in 
significantly reduced dioxin/furan levels.121 The other 
technology is activated carbon injected into the kiln exhaust gas. 
Since activated carbon injection is not currently used by any hazardous 
waste burning cement kilns, this technology was evaluated only as part 
of a beyond-the-floor analysis.
---------------------------------------------------------------------------

    \121\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards. Volume III: Selection of Proposed MACT Standards and 
Technologies'', July 1999. See Section 3.2.1.
---------------------------------------------------------------------------

    As discussed in the May 1997 NODA, specifying a temperature 
limitation of 400 deg.F or lower is appropriate for floor control 
because, from an engineering perspective, it is within the range of

[[Page 52876]]

reasonable values that could have been selected considering that: (1) 
The optimum temperature window for surface-catalyzed dioxin/furan 
formation is approximately 450-750 deg.F; and (2) temperature levels 
below 350 deg.F can cause dew point condensation problems resulting in 
particulate matter control device corrosion, filter cake cementing 
problems, increased dust handling problems, and reduced performance of 
the control device. (62 FR at 24226.)
    Several commenters disagreed with our selection of 400 deg.F as the 
particulate matter control device temperature limitation and stated 
that other higher temperature limitations were equally appropriate as 
MACT floor control. Based on these NODA comments, we considered 
selecting a temperature limitation of 450 deg.F, generally regarded to 
be the lower end of the temperature range of optimum dioxin/furan 
formation. However, available data indicate that dioxin/furan formation 
can be accelerated at kilns operating their particulate matter control 
device at temperatures between 400-450 deg.F. Data from several kilns 
show dioxin/furan emissions as high as 1.76 ng TEQ/dscm when operating 
in the range of 400-450 deg.F. Identifying a higher temperature limit 
such as 450 deg.F is not consistent with other sources achieving much 
lower emissions at 400 deg.F, and thus identifying a higher temperature 
limit would not be MACT floor control.
    Some commenters also state that EPA has failed to demonstrate that 
the best performing 12 percent of existing sources currently use 
temperature control to reduce dioxin/furan emissions, and therefore, 
temperature control is more appropriately considered in subsequent 
beyond-the-floor analyses. However, particulate matter control device 
operating temperatures associated with the emissions data used to 
establish the dioxin/furan standard are based on the maximum operating 
limits set during compliance certification testing required by the 
Boiler and Industrial Furnace rule. See 40 CFR 266.103(c)(1)(viii). As 
such, cement kilns currently must comply with these temperature limits 
on a continuous basis during day-to-day operations, and therefore, 
these temperature limits are properly assessed during an analysis of 
MACT floors.
    Several commenters also oppose consideration of dioxin/furan 
emissions data from nonhazardous waste burning cement kilns in 
establishing the floor standard. Commenters state that pooling the 
available emissions data from hazardous waste burning cement kiln with 
data from nonhazardous waste burning cement kilns to determine the MACT 
floor violates the separate category approach that EPA decided upon for 
the two classes of cement kilns. Notwithstanding our decision to divide 
the Portland cement manufacturing source category based on the kiln's 
hazardous waste burning status, we considered both hazardous waste 
burning cement kiln and nonhazardous waste burning cement kiln data 
together because both data sets are adequately representative of 
general dioxin/furan behavior and control in either type of kiln. This 
similarity is based on our engineering judgement that hazardous waste 
burning does not have an impact on dioxin/furan formation, dioxin/furan 
is formed post-combustion. Though the highest dioxin/furan emissions 
data point from MACT (i.e., operating control device less than 
400 deg.F) hazardous waste and nonhazardous waste burning cement kiln 
sources varies somewhat (0.28 vs 0.37 ng TEQ/dscm respectively), it is 
our judgment that additional emissions data, irrespective of hazardous 
waste burning status, would continue to point to a floor of within the 
range of 0.28 to 0.37 ng TEQ/dscm. This approach ensures that the floor 
levels for hazardous waste burning cement kilns are based on the 
maximum amount of relevant data, thereby ensuring that our judgment on 
what floor level is achievable is as comprehensive as possible.
    We estimate that approximately 70 percent of test condition data 
from hazardous waste burning cement kilns are currently emitting less 
than 0.40 ng TEQ/dscm (irrespective of the inlet temperature to the 
particulate matter control device). In addition, approximately 50 
percent of all test condition data are less than 0.20 ng TEQ/dscm. The 
national annualized compliance cost for cement kilns to reduce dioxin/
furan emissions to comply with the floor standard is $4.8 million for 
the entire hazardous waste burning cement industry and will reduce 
dioxin/furan emissions by 5.4 g TEQ/yr or 40 percent from current 
baseline emissions.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? We considered in the April 1996 proposal and May 1997 NODA a 
beyond-the-floor standard of 0.20 ng TEQ/dscm based on activated carbon 
injection at a temperature of less than 400 deg.F. We continue to 
believe that a beyond-the-floor standard 0.20 ng TEQ/dscm based on 
activated carbon injection is the appropriate beyond-the-floor standard 
to evaluate given the risks posed by dioxin/furan emissions.
    Carbon injection is routinely effective at removing 99 percent of 
dioxin/furans for numerous municipal waste combustor and mixed waste 
incinerator applications and one hazardous waste incinerator 
application. However, currently no hazardous waste burning cement kilns 
use activated carbon injection for dioxin/furan removal. For cement 
kilns, we believe that it is conservative to assume only 95 percent is 
achievable given that the floor level is already low at 0.40 ng/dscm. 
As dioxin/furans decrease, activated carbon injection efficiency is 
expected to decrease. In addition, we assumed for cost-effectiveness 
calculations that cement kilns needing activated carbon injection to 
achieve the beyond-the-floor standard would install the activated 
carbon injection system after the normal particulate matter control 
device and add a new, smaller fabric filter to remove the injected 
carbon with the absorbed dioxin/furan and mercury.122 The 
costing approach addresses commenter's concerns that injected carbon 
may interfere with cement kiln dust recycling practices.
---------------------------------------------------------------------------

    \122\ We received many comments on the use of activated carbon 
injection as a beyond-the-floor control techniques at cement kilns. 
Since we do not adopt a beyond-the-floor standard based on activated 
carbon injection in the final rule, these comments and our responses 
to them are only discussed in our document that responds to public 
comments.
---------------------------------------------------------------------------

    The national incremental annualized compliance cost for the 
remaining cement kilns to meet this beyond-the-floor level, rather than 
comply with the floor controls, would be approximately $2.5 million for 
the entire hazardous waste burning cement industry and would provide an 
incremental reduction in dioxin/furan emissions nationally beyond the 
MACT floor controls of 3.7 g TEQ/yr. Based on these costs, 
approximately $0.66 million per g dioxin/furan removed, we determined 
that this dioxin/furan beyond-the-floor option for cement kilns is not 
justified. Therefore, we are not adopting a beyond-the-floor standard 
of 0.2 ng TEQ/dscm.
    We note that one possible explanation of high cost-effectiveness of 
the beyond-the-floor standard may be due to the significant reduction 
in national dioxin/furan emissions achieved over the past several years 
by hazardous waste burning cement kilns due to emissions improving 
modifications. The hazardous waste burning cement kiln national dioxin/
furan emissions estimate for 1997 decreased by nearly

[[Page 52877]]

97% since 1990, from 431 g TEQ/yr to 13.1 g TEQ/yr.123
---------------------------------------------------------------------------

    \123\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume V: Emission Estimates and Engineering Costs'', 
July 1999. See also 63 FR 17338, April 10, 1998.
---------------------------------------------------------------------------

    c. What Is the MACT Floor for New Sources? At proposal, we 
identified floor control for new sources as temperature control at the 
inlet to the particulate matter control device at 409 deg.F. The 
proposed floor emission level was 0.20 ng TEQ/dscm, or temperature at 
the inlet to the particulate matter control device not to exceed 
409 deg.F. In the May 1997 NODA, we identified an alternative data 
analysis method to identify floor control and the floor emission level. 
The May 1997 NODA dioxin/furan floor control for new sources was 
defined as temperature control at the inlet to the electrostatic 
precipitator or fabric filter at 400 deg.F, which was based on an 
engineering evaluation of the emissions data and other available 
information. That analysis resulted in a floor emission level of 0.20 
ng TEQ/dscm, or 0.40 ng TEQ/dscm and temperature at the inlet to the 
electrostatic precipitator or fabric filter not to exceed 400 deg.F. We 
continue to believe that the floor methodology is appropriate for new 
sources and we adopt this approach in this final rule.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
both the April 1996 proposal and May 1997 NODA, we proposed activated 
carbon injection as beyond-the-floor control and a beyond-the-floor 
standard of 0.20 ng TEQ/dscm for new sources. For reasons discussed 
above for existing sources, we conclude that it is also not cost-
effective for new cement kilns to achieve this level. Thus, we do not 
adopt a beyond-the-floor dioxin/furan standard for new cement kilns.
3. What Are the Mercury Standards?
    In today's rule, we establish a standard for existing and new 
cement kilns that limits mercury emissions to 120 and 56 g/
dscm, respectively. The rationale for these standards is discussed 
below.
    a. What Is the MACT Floor for Existing Sources? All cement kilns 
use either electrostatic precipitators or fabric filters for 
particulate matter control. However, since mercury is generally in the 
vapor form in and downstream of the combustion chamber, including the 
air pollution control device, electrostatic precipitators and fabric 
filters do not achieve good mercury control. Mercury emissions from 
cement kilns are currently regulated by the Boiler and Industrial 
Furnace rule, which establishes limits on the maximum feedrate of 
mercury in total feedstreams (e.g., hazardous waste, raw materials, 
coal). Thus, MACT floor control is based on hazardous waste feed 
control.
    In the April 1996 proposal, we identified floor control as 
hazardous waste feedrate control not to exceed a feedrate level of 110 
g/dscm, expressed as a maximum theoretical emission 
concentration, and proposed a floor standard of 130 g/dscm 
based on an analysis of data from all cement kilns with a hazardous 
waste mercury feedrate of this level or lower. (61 FR at 17393.) In May 
1997 NODA, we conducted a breakpoint analysis on low to high ranked 
mercury emissions data from sources floor control and established the 
floor level as the test condition average emission of the breakpoint 
source. The breakpoint analysis was intended to reflect an engineering-
based evaluation of the data so that the few cement kilns spiking 
mercury during compliance testing did not drive the floor standard to 
levels higher than the preponderance of the emissions data. We reasoned 
that sources with emissions higher than the breakpoint source were not 
controlling the hazardous waste feedrate of mercury to levels 
representative of MACT. This analysis resulted in a MACT floor level of 
72 g/dscm. (62 FR at 24227.)
    For today's rule, in response to comments questioning our May 1997 
NODA approach, we use a revised engineering evaluation and data 
analysis method to establish the MACT floor for mercury. As discussed 
in greater detail in the methodology section previously, we use an 
aggregate feedrate approach to establish MACT floors for the three 
metal hazardous air pollutant groups and hydrochloric acid/chlorine 
gas. The aggregate feedrate approach first identifies a MACT floor 
feedrate level for mercury and then establishes the floor emission 
level as the highest emissions level achieved by any cement kilns using 
floor control or better. Using this approach, the resulting mercury 
floor emission level is 120 g/dscm.
    We received comments on several overarching issues including the 
appropriateness of considering feedrate control of mercury in hazardous 
waste as a MACT floor control technique and the specific procedure of 
identifying breakpoints in arrayed emissions data. These issues and our 
response to them are discussed in the floor methodology section in Part 
Four, Section V. In addition, we received comment on a special 
provision that would allow cement kilns (and lightweight aggregate 
kilns) to petition the Administrator for an alternative mercury 
standard for kilns with mercury concentrations in their mineral and 
related process raw materials that causes an exceedance of the emission 
standard. This issue and the alternative standard promulgated in the 
final rule is fully discussed in Part Five, Section X.A.
    We also received comments from the cement manufacturing industry 
indicating that cement kilns with in-line raw mills have unique design 
and operating procedures that necessitate the use of emission averaging 
when demonstrating compliance with the emission standards. These 
commenters stated that the mercury standard is not achievable without a 
procedure for kilns to emissions average. The commenters supported a 
provision allowing cement kilns with in-line raw mills to demonstrate 
compliance with the emission standards on a time-weighted average basis 
to account for different emission characteristics when the raw mill is 
active as opposed to when it is inactive. After fully considering 
comments received, we adopt an emission averaging provision in the 
final rule. This provision is fully discussed in Part Five, Section 
X.E.
    Several commenters expressed concern that the mercury emissions 
data base for cement kilns is comprised of normal data, that is, cement 
kilns did not spike mercury during RCRA compliance testing as they did 
for other metals and chlorine. Thus, commenters stated that an 
emissions variability factor should be added to a floor level derived 
directly from the emissions data to ensure that the floor emission 
level is being achieved in practice. As discussed in Section V.D.1 
above, we conclude that emissions variability is adequately accounted 
for by the MACT floor methodology finalized today.
    We estimate that 85 percent of cement kilns currently meet the 
floor level. The national annualized compliance cost for cement kilns 
to reduce mercury emissions to comply with the floor level is $1.1 
million for the entire hazardous waste burning cement industry and will 
reduce mercury emissions by 0.2 Mg/yr or 15 percent from current 
baseline emissions.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the April 1996 NPRM, we proposed a beyond-the-floor 
standard of 50 g/dscm based on flue gas temperature reduction 
to 400  deg.F followed by activated carbon injection for mercury 
capture. (61 FR at 17394.) In the May 1997 NODA, we considered a 
beyond-the-floor standard of 30 g/dscm based on activated 
carbon

[[Page 52878]]

injection; however, an evaluation was not conducted to determine if 
such a level would be cost-effective. (62 FR at 24227.)
    In developing the final rule, we identified three techniques for 
control of mercury as a basis to evaluate a beyond-the-floor standard: 
(1) Activated carbon injection; (2) limiting the feed of mercury in the 
hazardous waste; and (3) limiting the feed of mercury in the raw 
materials. The results of each analysis are discussed below.
    i. Activated Carbon Injection. To investigate activated carbon 
injection, we applied a carbon injection capture efficiency of 80 
percent to the floor emission level of 120 g/dscm. Our basis 
for selecting a capture efficiency of 80 percent 124 is 
discussed in the support document.125 The resulting beyond-
the-floor emission level is 25 g/dscm.
---------------------------------------------------------------------------

    \124\ We received many comments on the use of activated carbon 
injection as a beyond-the-floor control technique at cement kilns. 
Since we do not adopt a beyond-the-floor standard based on activated 
carbon injection in the final rule, these comments and our responses 
to them are only discussed in our document that responds to public 
comments.
    \125\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies.'' July 1999.
---------------------------------------------------------------------------

    We then determined the cost of achieving this reduction to 
determine if a beyond-the-floor standard of 25 g/dscm would be 
appropriate. The national incremental annualized compliance cost for 
the remaining cement kilns to meet this beyond-the-floor level, rather 
than comply with the floor controls, would be approximately $11.1 
million for the entire hazardous waste burning cement kiln industry and 
would provide an incremental reduction in mercury emissions nationally 
beyond the MACT floor controls of 0.7 Mg/yr. Based on these costs of 
approximately $16 million per additional Mg of mercury removed, we 
conclude that this mercury beyond-the-floor option for cement kilns is 
not acceptably cost-effective nor otherwise justified. Therefore, we do 
not adopt this beyond-the-floor standard.
    ii. Limiting the Feedrate of Mercury in the Hazardous Waste. We 
also considered a beyond-the-floor standard of 50 g/dscm based 
on limiting the feedrate of mercury in the hazardous waste. An emission 
level of 50 g/dscm represents the practicable extent that 
additional feedrate control of mercury in hazardous waste (beyond 
feedrate control needed to achieve the floor emission level) can be 
used and still achieve modest emissions reductions. We investigated the 
cost of achieving this reduction to determine if this beyond-the-floor 
standard would be appropriate. The national incremental annualized 
compliance cost for cement kilns to meet a beyond-the-floor level of 50 
g/dscm, rather than comply with the floor controls, would be 
approximately $4.2 million for the entire hazardous waste burning 
cement kiln industry and would provide an incremental reduction in 
mercury emissions nationally beyond the MACT floor controls of 0.4 Mg/
yr. Based on these costs of approximately $10.9 million per additional 
Mg of mercury removed, we conclude that this mercury beyond-the-floor 
option for cement kilns is not warranted. Therefore, we did not adopt 
this mercury beyond-the-floor standard.
    iii. Limiting the Feedrate of Mercury in Raw Materials. Finally, we 
considered a beyond-the-floor standard based on limiting the feedrate 
of mercury in the raw materials. Cement manufacturing involves the 
heating of raw materials such as limestone, clay, shale, sand, and iron 
ore. Limestone, shale, and clay comprise the vast majority of raw 
material feed to the kiln, and these materials are typically mined at 
quarries nearby the cement kiln. Since feed materials can contain 
significant quantities of hazardous air pollutants, we considered 
establishing a beyond-the-floor standard based on limiting the feedrate 
of mercury in these raw materials. A source can achieve a reduction in 
mercury emissions by substituting a feed material containing lower 
levels of mercury for a primary raw material with higher mercury 
levels. For example, shale is the primary feed material used as a 
source of silica. Under this beyond-the-floor option, a source using a 
high mercury-containing shale could substitute a feed material lower in 
mercury such as a coal ash to achieve lower mercury emissions. This 
beyond-the-floor option appears to be less cost-effective compared to 
either of the options evaluated above, however. This conclusion is 
based on the fact that cement kilns are sited proximate to primary raw 
material supply and transporting large quantities of an alternative 
source of raw material(s) is likely to be cost-prohibitive, thereby 
making a beyond-the-floor standard not cost-effective. Therefore, we do 
not adopt this mercury beyond-the-floor standard.
    Thus, the promulgated mercury standard for existing hazardous waste 
burning cement kilns is the floor level of 120 g/dscm.
    c. What Is the MACT Floor for New Sources? In the April 1996 
proposal, we identified floor control for new sources as hazardous 
waste mercury feedrate control not to exceed a feedrate level of 28 
g/dscm expressed as a maximum theoretical emission 
concentration. We proposed a floor level of 82 g/dscm. We 
discussed a floor emission level for new cement kilns in the May 1997 
NODA of 72 g/dscm, based on a floor feedrate control level of 
110 g/dscm.
    Today we identify floor control for new cement kilns as feedrate 
control of mercury in the hazardous waste, expressed as a maximum 
theoretical emission concentration, based on the single source with the 
best aggregate feedrate of mercury in hazardous waste. Using the 
aggregate feedrate approach to establish this floor level of control 
and the corresponding floor emission level, we identify a MACT floor 
emission level of 56 g/dscm for new hazardous waste burning 
cement kilns.126
---------------------------------------------------------------------------

    \126\ Given that the emission level is substantially higher than 
the feedrate level expressed as a maximum theoretical emission 
concentration, 56 vs 7 g/dscm, the contributions of mercury 
from raw materials and coal for the floor-setting source must be 
substantial.
---------------------------------------------------------------------------

    d. What Are Our Beyond-the-Floor Considerations for New Sources? At 
proposal, we based beyond-the-floor control for new cement kilns on 
activated carbon injection and proposed a standard of 50 g/
dscm. In the May 1997 NODA we considered a beyond-the-floor standard of 
30 g/dscm based on activated carbon injection as done for 
existing sources.
    We identified two techniques for control of mercury as a basis to 
evaluate a beyond-the-floor standard for new sources: (1) Activated 
carbon injection; and (2) limiting the feedrate of mercury in the 
hazardous waste. The results of each analysis are discussed below.
    i. Activated Carbon Injection. As discussed above, we conclude that 
flue gas temperature reduction to 400 deg.F followed by activated 
carbon injection to remove mercury is an appropriate beyond-the-floor 
control option for improved mercury control at cement kilns. Based on 
the MACT floor emission level of 56 g/dscm and assuming a 
carbon injection capture efficiency of 80 percent, we identified a 
beyond-the-floor emission level of 10 g/dscm. We then 
determined the cost of achieving this reduction to determine if a 
beyond-the-floor standard of 10 g/dscm would be appropriate. 
The incremental annualized compliance cost for one new large cement 
kiln to meet this beyond-the-floor level, rather than comply with floor 
controls, would be approximately $2.3 million and would provide an 
incremental reduction in mercury emissions beyond the MACT floor 
controls of approximately 0.17 Mg/yr. For a new small cement kiln, the

[[Page 52879]]

incremental annualized compliance cost would be approximately $0.9 
million and would provide an incremental reduction in mercury emissions 
beyond the MACT floor controls of approximately 0.04 Mg/yr. Based on 
these costs of approximately $13-22 million per additional Mg of 
mercury removed, we concluded that a beyond-the-floor standard of 10 
g/dscm is not justified due to the high cost of compliance and 
relatively small mercury emissions reductions.
    ii. Limiting the Feedrate of Mercury in Hazardous Waste. We also 
considered a beyond-the-floor standard based on limiting the feedrate 
of mercury in the hazardous waste. Considering that the floor emission 
level for new cement kilns is approximately half of the floor emission 
level for existing kilns (56 versus 120 g/dscm), we conclude 
that a mercury beyond-the-floor standard for cement kilns is not 
warranted. This conclusion is based on the limited incremental 
emissions reductions achieved 127 and because the cost-
effectiveness of beyond-the-floor controls for new cement kilns would 
be even higher than for existing sources, which we found unacceptable 
in paragraph (b) above. Therefore, we do not adopt a mercury beyond-
the-floor standard based on limiting feedrate of mercury in hazardous 
waste.
---------------------------------------------------------------------------

    \127\ Achieving substantial additional mercury emissions 
reductions by further controls on hazardous waste feedrate may be 
problematic because the mercury contribution from raw materials and 
coal represents an even larger proportion of the total mercury fed 
to the kiln.
---------------------------------------------------------------------------

    Thus, the promulgated mercury standard for new hazardous waste 
burning cement kilns is the floor emissions level of 56 g/
dscm.
4. What Are the Particulate Matter Standards?
    We establish standards for both existing and new cement kilns which 
limit particulate matter emissions to 0.15 kg/Mg dry 
feed.128 In addition, opacity cannot exceed 20 percent. We 
chose the particulate matter standard as a surrogate control for the 
metals antimony, cobalt, manganese, nickel, and selenium. We refer to 
these five metals as ``nonenumerated metals'' because standards 
specific to each metal have not been established. The rationale for 
adopting these standards is discussed below.
---------------------------------------------------------------------------

    \128\ Approximately equivalent to a particulate matter 
concentration of 0.03 gr/dscf (69 mg/dscm) as expressed in the April 
1996 NPRM and May 1997 NODA. The calculation is approximate due to 
the different types of cement kilns and their associated flow rates.
---------------------------------------------------------------------------

    a. What Is the MACT Floor for Existing Sources? In the April 1996 
proposal, we discussed particulate matter floor control based upon the 
performance of a fabric filter with an air-to-cloth ratio of 2.3 acfm/
f, 2 resulting in a nominal floor emission level of 0.065 
gr/dscf. However, we believed it more appropriate to establish the 
floor standard based on the cement kiln 1971 New Source Performance 
Standard. (See discussion in 61 FR at 17392.) The 1971 New Source 
Performance Standard is 0.15 kg/Mg dry feed (0.30 lb/ton of dry feed). 
(see 40 CFR 60.60.) Cement kilns currently achieve this standard with 
well-designed and properly operated electrostatic precipitators and 
fabric filters.
    In the May 1997 NODA, we considered two data analysis methods to 
identify the particulate matter floor emission level. The first method 
established and expressed the floor level equivalent to the existing 
New Source Performance Standard promulgated in 1971. We subsequently 
proposed and finalized this approach for nonhazardous waste burning 
cement kilns. See 63 FR at 14198-199 and 64 FR 31898, respectively. The 
second approach discussed expressed the New Source Performance Standard 
as a stack gas concentration limit, as opposed to a production-based 
emission limit format. The May 1997 reevaluation suggested that the 
1971 New Source Performance Standard was approximately equivalent to a 
particulate matter concentration of 0.03 gr/dscf (69 mg/
dscm).129 We indicated a preference for expressing the 
particulate matter standard on a concentration basis because we also 
proposed that sources would comply with the particulate matter standard 
with a particulate matter continuous emissions monitoring system.
---------------------------------------------------------------------------

    \129\ See USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999 for a discussion of the approximate 
equivalency.
---------------------------------------------------------------------------

    However, we now conclude that basing the floor on the 1971 New 
Source Performance Standard is the most appropriate approach. Cement 
kilns achieve the 1971 New Source Performance Standard with well-
designed and properly operated fabric filters and electrostatic 
precipitators. Since approximately 20% of hazardous waste burning 
cement kilns now are subject to the 1971 New Source Performance 
Standard, consideration of this existing federal regulation as a floor 
is appropriate because greater than 12% of existing sources are 
achieving it. The available emissions test data show a wide range of 
particulate matter results--some emissions data are well below while 
other data are at the 1971 New Source Performance Standard 
level.130 Even though the hazardous waste burning cement 
kiln particulate matter data span two orders of 
magnitude,131 we have limited data on design parameters of 
the particulate matter control device and could not identify a cause 
(i.e., differentiate among control equipment) for the wide range in 
particulate matter emissions. We thus believe that the variation 
reflects normal operating variability. Therefore, the MACT floor 
emission level for existing cement kilns is the 1971 New Source 
Performance Standard.
---------------------------------------------------------------------------

    \130\ The variation in the particulate matter data is consistent 
with data from nonhazardous waste burning cement kilns. We neither 
expect nor have any data indicating that waste-burning operations 
increase particulate matter emissions at a cement kiln. An estimated 
30% of existing nonhazardous waste burning cement kilns are subject 
to the requirements of the new Source Performance Standard for 
cement plants. The particulate matter data for these kilns also 
exhibit a wide range in measurements. (63 FR at 14198.)
    \131\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    The New Source Performance Standard at Sec. 60.62 also specifies 
that opacity must be monitored continuously and establishes an opacity 
standard of 20 percent as a measure to ensure compliance with the 
particulate matter standard. We are therefore also adopting this 
opacity standard for today's rule.132 We are adopting it for 
the final rule because: (1) We proposed to base the particulate matter 
standard for hazardous waste burning cement kilns on the New Source 
Performance Standard, and the opacity standard is an integral component 
of that standard; and (2) we proposed to base the MACT particulate 
matter standard for nonhazardous waste burning cement kilns on the New 
Source Performance Standard and explicitly identified both the 
particulate emission and opacity components of the standard. Hazardous 
waste burning cement kiln stakeholders have commented on both the 
nonhazardous waste and hazardous waste cement kiln proposed rules and 
suggest that there is little or no difference in emissions from the two 
classes of kilns and that they should be regulated the same. Although 
we do not agree that emissions of all hazardous pollutants are the same 
for both classes of kilns and should be regulated the same, we agree 
that particulate

[[Page 52880]]

emissions are comprised largely of entrained raw material and are not 
significantly affected by burning hazardous waste. Thus, we concur that 
the standard for particulate matter should be the same for both classes 
of sources and are therefore adopting the New Source Performance 
Standard opacity standard for the final rule.133 In the NPRM 
and the May 1997 NODA, we proposed to express the particulate matter 
standard on a concentration basis rather than express it as the same 
format as the 1971 New Source Performance Standard, which is a 
production-based emission limit format. However, because we are not yet 
requiring sources to document compliance with the particulate matter 
standard by using a particulate matter continuous emissions monitoring 
system in this final rule 134, we establish and express the 
floor emission level equivalent to the 1971 New Source Performance 
Standard. Thus, the particulate matter floor is 0.15 kg/Mg dry feed 
based on the performance of a well-designed and operated fabric filter 
or electrostatic precipitator.
---------------------------------------------------------------------------

    \132\ Given that we adopt the New Source Performance Standard 
for particulate matter and opacity for the MACT standards for 
hazardous waste burning cement kilns, we exempt these sources from 
the New Source Performance Standard to avoid duplicative regulation. 
See Sec. 63.1204(h).
    \133\ We are not adopting the opacity standard component of the 
New Source Performance Standard for hazardous waste burning 
lightweight aggregate kilns, however. This is because that opacity 
standard (see Sec. 60.732) is a measure to ensure compliance with 
the particulate emissions component of that standard, which is 
substantially higher than the MACT standard that we promulgate 
today. Thus, the NSPS opacity standard for lightweight aggregate 
kilns would not be a useful measure of compliance with today's 
particulate matter standard for lightweight aggregate kilns.
    \134\ We anticipate rulemaking on a particulate matter 
continuous emissions monitoring system requirement for hazardous 
waste combustors in the near future. Under this rulemaking, 
combustors would be required to document compliance with national 
emission standards by complying with continuous emissions monitoring 
system-based particulate matter levels that are being achieved by 
sources equipped with MACT controls. See Part Five, Section VII.C. 
for details.
---------------------------------------------------------------------------

    Several commenters expressed concern in their comments to the NPRM 
that the Agency identified separate, different MACT pools and 
associated MACT controls for particulate matter, semivolatile metals, 
and low volatile metals, even though all three are controlled, at least 
in part, by a particulate matter control device. Commenters stated that 
our approach is likely to result in three different design 
specifications. We agree with the need to use the same pool for 
particulate matter, semivolatile metals, and low volatile metals and 
used the same initial MACT pool to establish the floor levels for these 
pollutants. See Part Four, Section V for a detailed discussion of our 
floor methodology.
    We estimate that over 60 percent of cement kilns currently meet the 
floor emission level. The national annualized compliance cost for 
cement kilns to reduce particulate matter emissions to comply with the 
floor level is $6.2 million for the entire hazardous waste burning 
cement industry and will reduce nonenumerated metals and particulate 
matter emissions by 1.1 Mg/yr and 873 Mg/yr, respectively, or over 30 
percent from current baseline emissions.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the proposal and May 1997 NODA, we considered a beyond-the-
floor level of 34 mg/dscm (0.015 gr/dscf) based on improved particulate 
matter control. However, after examining the costs of such control and 
the relatively low incremental reductions in air emissions that would 
result, we determined that a beyond-the-floor standard would not likely 
be cost-effective. (61 FR at 17393.)
    Several commenters support a beyond-the-floor option for 
particulate matter because some cement kilns are readily achieving 
particulate matter levels well below the floor emission level based on 
the New Source Performance Standard. Other commenters oppose a beyond-
the-floor option for cement kilns because of the high costs and 
anticipated poor cost-effectiveness. In the final rule, we evaluated a 
beyond-the-floor emission level for existing cement kilns to determine 
if such a level would be appropriate.
    Improved particulate matter control for existing cement kilns would 
require the use of high efficiency electrostatic precipitators and 
fabric filters. These may include fabric filters with low air-to-cloth 
ratios, high performance fabrics, electrostatic precipitators with 
large specific collection areas, and advanced control systems. 
Currently, the majority of hazardous waste burning cement kilns use 
electrostatic precipitators for particulate matter control and usually 
achieve removal efficiencies greater than 99.8%. Cement kilns can meet 
the MACT floor with well designed and properly operated particulate 
matter control equipment that for many kilns may require only minor 
system upgrades from their current systems. A beyond-the-floor 
standard, however, would likely involve more than a minor system 
upgrade, and may require new control equipment or retrofitting a 
baghouse with new higher performance fabric materials. The total 
annualized costs associated with such major system upgrades would be 
significant, while only achieving modest incremental emissions 
reductions in particulate matter and nonenumerated metals.
    In the final rule, we considered a beyond-the-floor level of 34 mg/
dscm, approximately one-half the New Source Performance Standard, for 
existing cement kilns based on improved particulate matter control. For 
analysis purposes, improved particulate matter control entails the use 
of higher quality fabric filter bag material. We then determined the 
cost of achieving this level of particulate matter, with corresponding 
reductions in the nonenumerated metals for which particulate matter is 
a surrogate, to determine if this beyond-the-floor level would be 
appropriate. The national incremental annualized compliance cost for 
cement kilns to meet this beyond-the-floor level, rather than comply 
with the floor controls, would be approximately $7.4 million for the 
entire hazardous waste burning cement kiln industry and would provide 
an incremental reduction in nonenumerated metals emissions nationally 
beyond the MACT floor controls of 0.7 Mg/yr. Based on these costs of 
approximately $10.7 million per additional Mg of nonenumerated metals 
emissions removed, we conclude that this beyond-the-floor option for 
cement kilns is not acceptably cost-effective nor otherwise justified. 
Therefore, we do not adopt this beyond-the-floor standard. The 
promulgated particulate matter standard for existing hazardous waste 
burning cement kilns is the floor emission level of 0.15 kg/Mg dry feed 
and opacity not to exceed 20 percent.
    c. What Is the MACT Floor for New Sources? In the proposal, we 
defined floor control based on the performance of a fabric filter with 
an air-to-cloth ratio of less than 1.8 acfm/ft2. As discussed for 
existing sources, we proposed the floor level based on the existing 
cement kiln New Source Performance Standard. 61 FR at 17400. In the May 
1997 NODA, we again considered basing the floor emission level on the 
New Source Performance Standard and solicited comment on the two 
alternatives to express the standard identical to those discussed above 
for existing cement kilns. (62 FR at 24228.)
    All cement kilns use fabric filters and electrostatic precipitators 
to control particulate matter. As discussed earlier, we have limited 
detailed information on the design and operation characteristics of 
existing control equipment currently used by cement kilns. As a result, 
we are unable to identify a specific design or technology that can 
consistently achieve lower emission levels than the controls used by 
cement kilns achieving the New Source Performance Standard. Cement 
kilns meet the New Source Performance Standard with well-

[[Page 52881]]

designed and properly operated fabric filters and electrostatic 
precipitators. Thus, floor control for new cement kilns is also a well-
designed and properly operated fabric filter and electrostatic 
precipitator. As discussed for existing sources, we conclude that 
expressing the floor based on the New Source Performance Standards is 
appropriate for the final rule. Therefore, the MACT floor level for new 
cement kilns is 0.15 kg/Mg dry feed and opacity not to exceed 20 
percent.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the April 1996 NPRM and May 1997 NODA, we considered a beyond-the-floor 
standard based on improved particulate matter control to be consistent 
with existing sources. However, we proposed that such a beyond-the-
floor level was not likely cost-effective.
    As discussed for existing sources, we considered a beyond-the-floor 
level of 34 mg/dscm, approximately one-half the New Source Performance 
Standard, for new cement kilns based on improved particulate matter 
control. For analysis purposes, improved particulate matter control 
entails the use of higher quality fabric filter bag material. We then 
determined the cost of achieving this level of particulate matter, with 
corresponding reductions in the nonenumerated metals for which 
particulate matter is a surrogate, to determine if this beyond-the-
floor level would be appropriate. The incremental annualized compliance 
cost for one new large cement kiln to meet this beyond-the-floor level, 
rather than comply with floor controls, would be approximately $309,000 
and would provide an incremental reduction in nonenumerated metals 
emissions of approximately 0.18 Mg/yr.135 For a new small 
cement kiln, the incremental annualized compliance cost would be 
approximately $120,000 and would provide an incremental reduction in 
nonenumerated metals emissions of approximately 0.04 Mg/yr. Based on 
these costs of approximately $1.7-3.0 million per additional Mg of 
nonenumerated metals removed, we conclude that a beyond-the-floor 
standard of 0.015 gr/dscf is not justified due to the high cost of 
compliance and relatively small nonenumerated metals emission 
reductions. Thus, the particulate matter standard for new cement kilns 
is the floor level of 0.15 kg/Mg dry feed and opacity not to exceed 20 
percent.
---------------------------------------------------------------------------

    \135\ Based on the data available, the average emissions in sum 
of the five nonenumerated metals from cement kilns using MACT 
particulate matter control is approximately 80 g/dscm. To 
estimate emission reductions of the nonenumerated metals, we assume 
a linear relationship between a reduction in particulate matter and 
these metals.
---------------------------------------------------------------------------

5. What Are the Semivolatile Metals Standards?
    Today's rule establishes standards for existing and new cement 
kilns that limit semivolatile metals emissions to 240 and 180 
g/dscm, respectively. The rationale for these standards is 
discussed below.
    a. What Is the MACT Floor for Existing Sources? In the April 1996 
proposal, we defined floor control as a fabric filter with an air-to-
cloth ratio less than 2.1 acfm/ft 2 and a hazardous waste 
feedrate level of 84,000 g/dscm, expressed as a maximum 
theoretical emission concentration. The proposed floor emission level 
was 57 g/dscm, based on the level a source with properly 
designed and operated floor technology could achieve. In the proposed 
rule, we also solicited comment on an alternative floor approach 
whereby ``equivalent technology'' to MACT control is identified and 
evaluated. This approach resulted in an emission level of 160 
g/dscm (See 61 FR at 17395.) In the May 1997 NODA, we 
discussed a floor methodology where we used a breakpoint analysis to 
identify sources that were not using floor control with respect either 
to semivolatile metals hazardous waste feedrate or emissions control. 
Under this approach, we ranked semivolatile metals emissions data from 
sources that were using MACT floor particulate matter control, i.e., 
sources achieving the New Source Performance Standard or better. We 
identified the floor level as the test condition average associated 
with the breakpoint source. Thus, sources with atypically high 
emissions because of high semivolatile metals feedrates or poor 
semivolatile metals control even though they appeared to be using floor 
control for particulate matter were screened from the pool of sources 
used to define the floor emission level. Based on this analysis, we 
identified a floor level in the May 1997 NODA of 670 g/dscm. 
(See 62 FR at 24228.)
    As discussed previously in the methodology section, we use a 
revised engineering evaluation and data analysis method to establish 
the MACT floor for semivolatile metals based on the same underlying 
data previously noticed for comment. The aggregate feedrate approach, 
in conjunction with floor control for particulate matter, identified a 
semivolatile metals floor emission level of 650 g/dscm.
    In addition, several commenters stated strongly that the feedrate 
of semivolatile metals in hazardous waste cannot be considered MACT 
floor control in conjunction with particulate matter control. These 
commenters believe that floor control for semivolatile metals is 
control of particulate matter only. We disagree with these commenters 
for reasons we discuss in Part Four, Section V of the preamble, mainly 
that feedrate is currently control for hazardous waste combustors under 
RCRA regulations, and conclude that control of the feedrate of 
semivolatile metals in hazardous waste is floor control, in conjunction 
with particulate matter control.
    We estimate that approximately 60 percent of cement kilns currently 
meet this floor level. The national annualized compliance cost for 
cement kilns to reduce semivolatile metal emissions to comply with the 
floor level is $1.3 million for the entire hazardous waste burning 
cement industry and will reduce semivolatile metal emissions by 19.5 
Mg/yr or 65 percent from current baseline emissions.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the proposal, we considered a beyond-the-floor standard for 
semivolatile metals based on improved particulate matter control below 
the New Source Performance Standard. However, we concluded that a 
beyond-the-floor standard would not be cost-effective, given that the 
semivolatile metal floor level of 57 g/dscm alone resulted in 
an estimated 94 percent semivolatile metal reduction in emissions. (see 
61 FR at 17396.) In the May 1997 NODA, we considered a lower 
particulate matter emissions level of 0.015 gr/dscf, based on improved 
particulate matter control, as a beyond-the-floor standard to further 
reduce semivolatile and low volatile metals. Even though we did not 
quantify cost-effectiveness values, we expressed concern that a beyond-
the-floor standard would not likely be cost-effective. (see 62 FR at 
24229.)
    Commenters believed there were several control techniques that 
should be considered, therefore, we identified three potential beyond-
the-floor control techniques in developing the final rule: (1) Limiting 
the feedrate of semivolatile metals in hazardous waste; (2) improved 
particulate matter control; and (3) limiting the feedrate of 
semivolatile metals in raw materials. We conclude that a beyond-the-
floor standard is warranted based on limiting the feedrate of 
semivolatile metals in hazardous waste. The results of each analysis 
are discussed below.
    i. Limiting the Feedrate of Semivolatile Metals in Hazardous Waste. 
Under this approach, we selected a beyond-the-floor emission level of 
240

[[Page 52882]]

g/dscm from among the range of possible levels that reflect 
improved feedrate control. This emission level represents a significant 
increment of emission reduction from the floor of 650 g/dscm, 
it is within the range of levels that are likely to be reasonably 
achievable using feedrate control, and it is consistent with the 
incinerator standard thereby advancing a potential policy objective of 
essentially common standards among combustors of hazardous waste.
    The national incremental annualized compliance cost for the 
remaining cement kilns to meet this beyond-the-floor level, rather than 
comply with the floor controls, would be approximately $2.7 million for 
the entire hazardous waste burning cement kiln industry and would 
provide an incremental reduction, beyond emissions at the MACT floor, 
in semivolatile metal emissions nationally of 5.5 Mg/yr. The cost-
effectiveness of this standard would be approximately $500,000 per 
additional Mg of semivolatile metals removed. Notwithstanding the 
relatively poor cost-effectiveness of this standard on a dollar per Mg 
removed basis, we conclude that additional beyond-the-floor control of 
the feedrate of semivolatile metals in hazardous waste to achieve an 
emission level of 240 g/dscm is warranted because this 
standard would reduce lead and cadmium emissions which are particularly 
toxic hazardous air pollutants. See Health Human Effects discussion in 
USEPA, ``Technical Background Document for HWC MACT Standards: Health 
and Ecological Risk Assessment'', July 1999. Further, approximately 90% 
of the lead and cadmium fed to the cement kiln is from the hazardous 
waste,136 not the raw material (about 9%) or coal (about 
1%). We are willing to accept a more marginal cost-effectiveness to 
ensure that hazardous waste combustion sources are using the best 
controls for pollutants introduced almost exclusively for the burning 
of hazardous waste. We do so to provide a strong incentive for waste 
minimization of lead and cadmium sent for combustion. By providing 
stringent limits, we can help assure that hazardous waste with lead 
does not otherwise move from better controlled units in other 
subcategories to units in this subcategory because of a lesser degree 
of control. Moreover, this beyond-the-floor semivolatile metal standard 
supports our Children's Health Initiative in that lead emissions, which 
are of highest significance to children's health, will be reduced by 
another 20-25 percent from today's baseline. As part of this 
initiative, we are committed to reducing lead emissions wherever and 
whenever possible. Finally, this beyond-the-floor standard is 
consistent with European Union standards for hazardous waste 
incinerators of approximately 200 g/dscm for lead and cadmium 
combined. For all these reasons, we accept the cost-effectiveness of 
this level of feedrate control and adopt a beyond-the-floor standard of 
240 g/dscm for existing cement kilns.
---------------------------------------------------------------------------

    \136\ USEPA, ``Final Technical Support document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies'', July 1999.
---------------------------------------------------------------------------

    Additionally, we received comments shortly before promulgation from 
the cement kiln industry that expressed their achievability and 
economic concerns with a beyond-the-floor standard in the range of 240 
g/dscm based on limiting the feedrate of semivolatile metals 
in the hazardous waste. We considered their comments in adopting the 
240 g/dscm beyond-the-floor standard and included a copy of 
their November 18, 1998 presentation to the Office of Management and 
Budget in the docket along with our responses to their concerns, many 
of which are addressed above.
    ii. Improved Particulate Matter Control. We also evaluated improved 
particulate matter control as a beyond-the-floor control option for 
improved semivolatile metals control. Cadmium and lead are volatile at 
the high temperatures within the cement kiln itself, but typically 
condense onto the fine particulate at control device temperatures, 
where they are collected. As a result, control of semivolatile metals 
emissions is closely associated with particulate matter control. 
Examples of improved particulate matter control include the use of more 
expensive fabric filter bags, optimizing the design and operation 
features of the existing control equipment, and the addition to or the 
replacement of control equipment with a new fabric filter.
    We evaluated the costs to achieve a beyond-the-floor emission level 
of 240 g/dscm based on improved particulate matter control. 
The national incremental annualized compliance cost for cement kilns to 
meet this beyond-the-floor level, rather the floor level, would be 
approximately $4.1 million for the entire hazardous waste burning 
cement kiln industry and would provide an incremental reduction in 
semivolatile metal emissions beyond the MACT floor controls of 5.5 Mg/
yr. Because this beyond-the-floor control option would have a cost-
effectiveness of approximately $800,00 per additional Mg of 
semivolatile metal removed, contrasted to a cost-effectiveness of 
approximately $500,000 using hazardous waste feedrate control and 
remove an identical amount of semivolatile metals, we conclude that 
basing the beyond-the-floor standard on improved particulate matter 
control is not warranted.
    iii. Limiting the Feedrate of Semivolatile Metals in Raw Materials. 
A source can achieve a reduction in semivolatile metal emissions by 
substituting a feed material containing lower levels of lead and/or 
cadmium for a primary raw material with higher levels of these metals. 
We expect this beyond-the-floor option to be less cost-effective 
compared to either of the options evaluated above. Cement kilns are 
sited proximate to primary raw material supply and transporting large 
quantities of an alternative source of raw material(s) is likely to be 
cost-prohibitive. Therefore, we are not adopting a semivolatile metal 
beyond-the-floor standard based on limiting the feedrate of 
semivolatile metals in raw materials.137
---------------------------------------------------------------------------

    \137\ We, however, reject the proposition in comments that we 
are without legal authority to regulate HAPs in raw materials 
processed in cement kilns based on legislative history to the 1990 
amendments. This legislative history is not reflected in the 
statutory text, which unambiguously gives us that authority.
---------------------------------------------------------------------------

    Thus, the promulgated semivolatile metals standard for existing 
hazardous waste burning cement kilns is a beyond-the-floor standard of 
240 g/dscm based on limiting the feedrate of semivolatile 
metals in the hazardous waste.
    c. What Is the MACT Floor for New Sources? In the proposal, we 
defined floor control as a fabric filter with an air-to-cloth ratio 
less than 2.1 acfm/ft 2 and a hazardous waste feedrate level 
of 36,000 g/dscm, expressed as a maximum theoretical emission 
concentration. The proposed floor emission level for new cement kilns 
was 55 g/dscm. (See 61 FR at 17400.) In the May 1997 NODA, we 
concluded that the floor control and emission level for existing 
sources for semivolatile metals also would be appropriate for new 
sources. Floor control was based on a combination of good particulate 
matter control and limiting hazardous waste feedrate of semivolatile 
metals. We used a breakpoint analysis of the semivolatile metal 
emissions data to exclude sources achieving substantially poorer 
semivolatile metal control than the majority of sources because of 
atypically high semivolatile metals feedrates or poor emission control. 
We established the floor level at the test condition average of the 
breakpoint source: 670 g/dscm. (See 62 FR at 24229.)
    As discussed above for existing sources, we developed the final 
rule

[[Page 52883]]

using the aggregate feedrate approach to identify MACT floors for the 
metals. See Methodology Section for detailed discussion of aggregate 
feedrate approach. Using this approach, we establish the semivolatile 
metal floor emission level for new sources at 180 g/dscm.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the April 1996 NPRM and May 1997 NODA, we considered a semivolatile 
metal beyond-the-floor emission level for new sources, but determined 
that it would not be cost-effective.
    For the final rule, we do not consider a beyond-the-floor level for 
new cement kilns because the MACT floor for new cement kilns is already 
lower than the beyond-the-floor emission standard for existing sources. 
As a result, a beyond-the-floor standard for new cement kilns is not 
warranted due to the likely significant costs of control and the 
minimal incremental emissions reductions. In addition, our policy goal 
of state of the art control of lead is achieved at the floor standard 
for new sources. We, therefore, adopt a semivolatile metal floor 
standard of 180 g/dscm for new hazardous waste burning cement 
kilns.
6. What Are the Low Volatile Metals Standards?
    We establish standards for existing and new cement kilns in today's 
rule that limit low volatile metal emissions to 56 and 54 g/
dscm, respectively. The rationale for these standards is discussed 
below.
    a. What Is the MACT Floor tor Existing Sources? In the April 1996 
NPRM, we defined floor control as either: (1) A fabric filter with an 
air-to-cloth ratio less than 2.3 acfm/ft \2\ and a hazardous waste 
feedrate level of 140,000 g/dscm, expressed as a maximum 
theoretical emission concentration; or (2) an electrostatic 
precipitator with a specific collection area of 350 ft \2\/kacfm and 
the same hazardous waste feedrate level of 140,000 g/dscm. The 
proposed floor level was 130 g/dscm. (See 61 FR at 17396.) In 
the May 1997 NODA, we used a breakpoint analysis to identify sources 
that were not using floor control with respect either to low volatile 
metals hazardous waste feedrate or emissions control. Under this 
approach, we ranked low volatile metals emissions data from sources 
that were achieving the particulate matter floor of 69 mg/dscm or 
better. We identified the floor level as the test condition average 
associated with the breakpoint source. Thus, sources with atypically 
high emissions because of high low volatile metals feedrates or poor 
low volatile metals control, even though they were using floor control 
for particulate matter, were screened from the pool of sources used to 
define the floor emission level. The May 1977 NODA MACT floor level was 
63 g/dscm. (See 62 FR at 24229.)
    We received limited comments in response to the NPRM and May 1997 
NODA concerning the low volatile metals floor standard. We received 
comments, however, on several overarching issues including the 
appropriateness of considering feedrate control of metals including low 
volatile metals in hazardous waste as a MACT floor control technique 
and the specific procedure of identifying breakpoints in arrayed 
emissions data. These issues and our responses to them are discussed in 
the floor methodology section in Part Four, Section V.
    Today we use a revised engineering evaluation and data analysis 
method to establish the MACT floor for low volatile metals on the same 
underlying data previously noticed for comment. As explained earlier, 
the aggregate feedrate approach, in conjunction with floor control for 
particulate matter, replaces the breakpoint analysis for metals and 
results in a low volatile metal floor emission level of 56 g/
dscm.
    We estimate that over 76 percent of cement kilns in our data base 
meet the floor level. The national annualized compliance cost for 
cement kilns to reduce low volatile metal emissions to comply with the 
floor level is $0.8 million for the entire hazardous waste burning 
cement industry, and will reduce low volatile metal emissions by 0.2 
Mg/yr or approximately 25 percent from current baseline emissions.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the proposal, we considered a beyond-the-floor standard for 
low volatile metals based on improved particulate matter control. 
However, we concluded that a beyond-the-floor standard would not likely 
be cost-effective based on the limited emissions reductions of low 
volatility metals. In the May 1997 NODA, we considered a lower 
particulate matter emissions level, based on improved particulate 
matter control, as a beyond-the-floor standard with corresponding 
beyond-the-floor reductions in low volatile and semivolatile metals. 
Even though we did not quantify cost-effectiveness values, we expressed 
concern that a beyond-the-floor standard would not likely be cost-
effective. (62 FR at 24229.)
    For today's final rule, we identified three potential beyond-the-
floor techniques for control of low volatile metals: (1) Improved 
particulate matter control; (2) limiting the feedrate of low volatile 
metals in the hazardous waste; and (3) limiting the feedrate of low 
volatile metals in the raw materials. We discuss the results of our 
analysis of each option below.
    Improved Particulate Matter Control. Our judgment is that a beyond-
the-floor standard based on improved particulate matter control would 
be less cost-effective than a beyond-the-floor standard based on 
limiting the feedrate of low volatile metals in the hazardous waste. 
First, our data show that all cement kilns are already achieving 
greater than a 99% system removal efficiency for low volatile metals, 
with most attaining 99.99% removal. Thus, equipment retrofit costs for 
improved control would be significant and result in only a small 
increment in reduction of emissions. Our beyond-the-floor analysis for 
semivolatile metals supports this conclusion. There, the semivolatile 
metals analysis showed that the beyond-the-floor option based on 
limiting the feedrate of semivolatile metals was approximately 30% more 
cost-effective than a beyond-the-floor option based on improved 
particulate matter control. We believe the low volatile metals would 
require similar particulate matter control device retrofits at cement 
kilns as for semivolatile metals. However, the total emissions 
reduction achieved would be less because hazardous waste burning cement 
kilns emit less low volatile metals than semivolatile metals. We do not 
have any of the serious concerns present for semivolatile metals that 
suggest we should accept a more marginal cost-effectiveness. Thus, we 
conclude that a beyond-the-floor standard for low volatile metals based 
on improved particulate matter control is not warranted.
    Limiting the Feedrate of Low Volatile Metals in the Hazardous 
Waste. We also considered a beyond-the-floor standard of 40 g/
dscm for low volatile metals based on additional feedrate control of 
low volatile metals in the hazardous waste. This would reduce the floor 
emission level by approximately 30 percent. Our investigation shows 
that this beyond-the-floor option would achieve an incremental 
reduction in low volatile metals of only 0.1 Mg/yr. Given that this 
beyond-the-floor level would not achieve appreciable emissions 
reductions, we conclude that cost-effectiveness considerations would 
likely come into play suggesting that this beyond-the-floor standard is 
not warranted.

[[Page 52884]]

    Limiting the Feedrate of Low Volatile Metals in the Raw Materials. 
Sources can achieve a reduction in low volatile metal emissions by 
substituting a feed material containing lower levels of arsenic, 
beryllium, and/or chromium for a primary raw material with higher 
levels of these metals. We believe that this beyond-the-floor option 
would be even less cost-effective than either of the options evaluated 
above, however. Cement kilns are sited proximate to primary raw 
material supply and transporting large quantities of an alternative 
source of raw material(s) is likely to be cost-prohibitive. Therefore, 
we do not adopt a low volatile metal beyond-the-floor standard based on 
limiting the feedrate of low volatile metals in raw materials.
    For the reasons discussed above, we do not adopt a beyond-the-floor 
level for low volatile metals and establish the emission standard for 
existing hazardous waste burning cement kilns at 56 g/dscm.
    c. What Is the MACT Floor for New Sources? In the proposal, we 
defined floor control as a fabric filter with an air-to-cloth ratio 
less than 2.3 acfm/ft2 and a hazardous waste feedrate 
control level of 25,000 g/dscm, expressed as a maximum 
theoretical emission concentration. The proposed floor for new cement 
kilns was 44 g/dscm. (61 FR at 17400.) In the May 1997 NODA, 
we concluded that the floor control and emission level for existing 
sources for low volatile metals would also be appropriate for new 
sources. Floor control was based on a combination of good particulate 
matter control and limiting hazardous waste feedrate of low volatile 
metals. We used a breakpoint analysis of the low volatile metal 
emissions data to exclude sources achieving substantially poorer low 
volatile metal control than the majority of sources. We established the 
floor level at the test condition average of the breakpoint source. The 
NODA floor was 63 g/dscm. (62 FR at 24230.)
    As discussed above for existing sources, in developing the final 
rule we use the aggregate feedrate approach to identify MACT floors for 
the metals and hydrochloric acid/chlorine gas in combination with MACT 
floor control for particulate matter. Based on the low volatile metal 
feedrate in hazardous waste from the single best performing cement kiln 
using floor control for particulate matter, the MACT floor for new 
hazardous waste burning cement kilns is 54 g/dscm.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the proposal and May 1997 NODA, we considered a low volatile metal 
beyond-the-floor level for new sources, but determined it would not be 
cost effective. For reasons similar to those discussed for existing 
sources, we do not believe that a beyond-the-floor standard is 
warranted for new cement kilns due to the high expected compliance cost 
and relatively low reductions in emissions of low volatile metals. 
Therefore, we adopt a low volatile metals standard of 54 g/
dscm for new hazardous waste burning cement kilns.
7. What Are the Hydrochloric Acid and Chlorine Gas Standards?
    In today's rule, we establish standards for existing and new cement 
kilns that limit hydrochloric acid and chlorine gas emissions to 130 
and 86 ppmv, respectively. The rationale for these standards is 
discussed below.
    a. What Is the MACT Floor for Existing Sources? In the proposal, we 
identified floor control for hydrochloric acid/chlorine gas as feedrate 
control of chlorine in the hazardous waste and proposed a floor 
standard of 630 ppmv. (61 FR at 17396.) In the May 1997 NODA, we used a 
data analysis method similar to that at proposal and discussed a floor 
emission level of 120 ppmv. (62 FR at 24230.)
    Some commenters to the May 1997 NODA expressed concern that cement 
kilns may not be able to meet the hydrochloric acid/chlorine gas 
standard while making low alkali cement. Commenters noted that chlorine 
is sometimes added specifically to volatilize potassium and sodium 
compounds that must be removed to produce low alkali cement. One 
commenter manufacturing a low alkali cement submitted data showing a 
large range in hydrochloric acid/chlorine gas emissions while operating 
under varying conditions and production requirements. This commenter 
stated that they may not be able to meet the NODA hydrochloric acid/
chlorine gas standard of 120 ppmv while making low alkali cement. We 
conclude, however, that the data they submitted do not adequately 
support this ultimate conclusion. The commenter's emissions data range 
from 6 ppmv to 83 ppmv while operating under RCRA compliance testing 
conditions. These emission levels are well below the final standard of 
130 ppmv, and the expected operational range in this rule is 70% of the 
standard. We conclude that the hydrochloric acid/chlorine gas standard 
of 130 ppmv finalized today is readily achievable by all cement kilns 
irrespective of the type of cement manufactured.
    For today's rule, we use a revised engineering evaluation and data 
analysis method to establish the MACT floor for hydrochloric acid and 
chlorine gas on the same underlying data previously noticed for 
comment. Using the aggregate feedrate approach discussed previously, we 
establish a hydrochloric acid/chlorine gas floor emission level of 130 
ppmv.
    We estimate that approximately 88 percent of cement kilns in our 
data base currently meet the floor level. The national annualized 
compliance cost for cement kilns to reduce hydrochloric acid/chlorine 
gas emissions to comply with the floor level is $1.4 million for the 
entire hazardous waste burning cement industry and will reduce 
hydrochloric acid/chlorine gas emissions by 383 Mg/yr or 12 percent 
from current baseline emissions.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the proposal, we defined beyond-the-floor control as wet 
scrubbing with a 99 percent removal efficiency, but determined that a 
beyond-the-floor standard would not be cost-effective. (61 FR at 
17397.) In the May 1997 NODA, we identified a more stringent floor 
standard and therefore reasoned that a beyond-the-floor standard based 
on wet scrubbing would likely also not be cost-effective. (62 FR at 
24230.)
    For today's rule, we identified three potential beyond-the-floor 
techniques for control of hydrochloric acid/chlorine gas emissions: (1) 
Scrubbing; (2) limiting the feedrate of chlorine in the hazardous 
waste; and (3) limiting the feedrate of chlorine in the raw materials. 
We discuss our analysis of each option below.
    Scrubbing. We continue to believe that a beyond-the-floor standard 
based on dry or wet scrubbing is not likely to be cost-effective. 
Cement kilns achieve control of hydrochloric acid/chlorine gas 
emissions from alkaline raw materials in the kiln. Control 
effectiveness varies among kilns based on the alkalinity of the raw 
materials. Thus, the cement manufacturing process serves essentially as 
a dry scrubber. We conclude, therefore, that the addition of a dry 
scrubber will only marginally improve hydrochloric acid/chlorine gas 
removal and is not warranted as beyond-the-floor control.
    It is also our judgment that a beyond-the-floor standard based on 
wet scrubbing is not warranted. The total estimated engineering 
retrofit costs would be approximately equivalent to those identified at 
proposal for this option. However, emissions reductions would be less 
given that the final MACT floor level is more stringent than the

[[Page 52885]]

level proposed. Therefore, the cost-effectiveness of a beyond-the-floor 
standard would be less attractive than the number we rejected at 
proposal. As a result, we must reaffirm that conclusion here.
    Limiting the Feedrate of Chlorine in the Hazardous Waste. We also 
considered a beyond-the-floor standard for hydrochloric acid/chlorine 
gas based on additional feedrate control of chlorine in the hazardous 
waste. We are concerned, however, that cement kilns making low alkali 
cement may not be able to achieve a beyond-the-floor standard by 
controlling feedrate of chlorine in the hazardous waste. As noted 
above, chlorine is sometimes added specifically to volatilize potassium 
and sodium compounds that must be removed from the clinker to produce 
low alkali cement. Based on limited data submitted by a cement facility 
manufacturing low alkali cement, achievability of a beyond-the-floor 
standard of 70 ppmv, representing a 45% reduction from the floor level, 
may not be feasible for this source using feedrate control and others 
by inference. Therefore, we conclude that a beyond-the-floor standard 
based on chlorine feedrate control in the hazardous waste is not 
appropriate.
    Limiting the Feedrate of Chlorine in the Raw Materials. A source 
can achieve a reduction in hydrochloric acid/chlorine gas emissions by 
substituting a feed material containing lower levels of chlorine for a 
primary raw material with higher levels of chlorine. This beyond-the-
floor option is less cost-effective compared to the scrubbing options 
evaluated above because cement kilns are sited proximate to the primary 
raw material supply and transporting large quantities of an alternative 
source of raw material(s) is not technically achievable. Therefore, we 
do not adopt a hydrochloric acid/chlorine gas beyond-the-floor standard 
based on limiting the feedrate of chlorine in raw materials.
    In summary, we establish the hydrochloric acid/chlorine gas 
standard for existing hazardous waste burning cement kilns at the floor 
level of 130 ppmv.
    c. What Is the MACT Floor for New Sources? At proposal, we defined 
floor control for new sources as hazardous waste feedrate control for 
chlorine and the proposed floor level was 630 ppmv. (See 61 FR at 
17401.) In the May 1997 NODA, we concluded that the floor control and 
emission level for existing sources for hydrochloric acid/chlorine gas 
would also be appropriate for new sources. Floor control was based on 
limiting hazardous waste feedrates of chlorine. After screening out 
some data with anomalous system removal efficiencies compared to the 
majority of sources, we established the floor level at the test 
condition average of the breakpoint source. We identified a floor level 
for new kilns of 120 ppmv. (See 62 FR at 24230.)
    As discussed above for existing sources, in developing the final 
rule, we use the aggregate feedrate approach to identify MACT floors 
for hydrochloric acid/chlorine gas. The resulting MACT emissions floor 
for new hazardous waste burning cement kilns is 86 ppmv.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the proposal, we considered a beyond-the-floor standard for new cement 
kilns of 67 ppmv based on wet scrubbing and concluded that it would not 
be cost-effective. In the May 1997 NODA, we also concluded that a 
beyond-the-floor standard based on wet scrubbing would likewise not be 
cost-effective. Considering the level of the floor standard for new 
kilns, we do not believe that a more stringent beyond-the-floor 
standard is warranted for the final rule, especially considering our 
concerns for cement kilns manufacturing low alkali cements.
    In summary, we adopt the floor level of 86 ppmv as the standard for 
hydrochloric acid/chlorine gas for new sources.
8. What Are the Hydrocarbon and Carbon Monoxide Standards for Kilns 
Without By-Pass Sampling Systems? 138
---------------------------------------------------------------------------

    \138\ See USEPA, ``Final Technical Support Document for 
Hazardous Waste Combustor MACT Standards, Volume I: Description of 
Source Categories,'' July 1999, for further explanation of by-pass 
and midkiln sampling systems. Hydrocarbon and carbon monoxide 
standards for kilns equipped with by-pass sampling systems are 
discussed in Section VI.D.9 f the text.
---------------------------------------------------------------------------

    See Sec. 63.1205(a)(5) and (b)(5).
    In today's rule, we establish hydrocarbon and carbon monoxide 
standards for new and existing cement kilns without by-pass sampling 
systems as surrogates to control emissions of nondioxin organic 
hazardous air pollutants. The standards for existing sources limit 
hydrocarbon or carbon monoxide concentrations to 20 ppmv \139\ or 100 
ppmv, \140\ respectively. The standards for new sources limit: (1) 
Hydrocarbons to 20 ppmv; or (2) carbon monoxide to 100. New, greenfield 
\141\ kilns that elect to comply with the 100 ppmv carbon monoxide 
standard, however, must also comply with a 50 ppmv \142\ hydrocarbon 
standard. New and existing sources that elect to comply with the 100 
ppmv carbon monoxide standard, including new greenfield kilns that 
elect to comply with the carbon monoxide standard and 50 ppmv 
hydrocarbon standard, must also demonstrate compliance with the 20 ppmv 
hydrocarbon standard during the comprehensive performance test.\143\ 
(See Part Four, Section IV.B of the preamble for the rationale for this 
requirement.) We discuss the rationale for these standards below.
---------------------------------------------------------------------------

    \139\ Hourly rolling average, reported as propane, dry basis, 
and corrected to 7% oxygen.
    \140\ Hourly rolling average, dry basis, corrected to 7% oxygen.
    \141\ A greenfield cement kiln is a kiln that commenced 
construction or reconstruction after April 19, 1996 at a site where 
no cement kiln previously existed, irrespective of the class of kiln 
(i.e., nonhazardous waste or hazardous waste burning). A newly 
constructed or reconstructed cement kiln at an existing site would 
not be classified as a greenfield cement kiln, and would be subject 
to the same carbon monoxide and hydrocarbon standards as an existing 
cement kiln.
    \142\ Thirty day block average, reported as propane, dry basis, 
and corrected to 7 percent oxygen.
    \143\ As discussed in Part 5, Section X.F, sources that feed 
hazardous waste at a location other than the end where products are 
normally discharged and where fuels are normally fired must comply 
with the 20 ppmv hydrocarbon standard i.e., these sources do not 
have the option to comply with the carbon monoxide standard).
---------------------------------------------------------------------------

    a. What Is the MACT Floor for Existing Sources? As discussed in 
Part Four, Section II.B.2, we proposed limits on hydrocarbon emissions 
for kilns without by-pass sampling systems as a surrogate to control 
nondioxin organic hazardous air pollutants. In the April 1996 proposal 
(61 FR at 17397), we identified a hydrocarbon floor emission level of 
20 ppmv for cement kilns not equipped with by-pass sampling systems, 
and proposed that floor control be based on the current federally-
enforceable RCRA boiler and industrial furnace standards, control of 
organics in raw materials coupled with operating under good combustion 
practices to minimize fuel-related hydrocarbon. In the May 1997 NODA, 
we also indicated that this approach was appropriate.
    Some commenters stated that a carbon monoxide limit of 100 ppmv was 
necessary for these cement kilns to better control organic hazardous 
air pollutants. Commenters also wrote that, alone, neither carbon 
monoxide nor hydrocarbons is an acceptable surrogate for organic 
hazardous air pollutant emissions. Additionally, commenters suggested 
that by requiring both carbon monoxide and hydrocarbon limits, we would 
further reduce emissions of organic hazardous air pollutants.
    We conclude that continuous compliance with both a carbon monoxide 
and hydrocarbon standard is unwarranted for the following reasons. 
First, stack gas carbon monoxide levels are not a universally reliable 
indicator

[[Page 52886]]

of combustion intensity and efficiency for kilns without by-pass 
sampling systems. This is due to carbon monoxide generation by 
disassociation of carbon dioxide to carbon monoxide at the high 
sintering zone temperatures and evolution of carbon monoxide from the 
trace organic constituents in raw material feedstock.\144\ (See 56 FR 
at 7150, 7153-55). Thus, carbon monoxide can be a too conservative 
surrogate for this type of kiln for potential emissions of hazardous 
air pollutants from combustion of hazardous waste. There are other 
sources of carbon monoxide unrelated to combustion of hazardous 
waste.\145\
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    \144\ Raw materials enter the upper end of the kiln and move 
counter-current to the combustion gas. Thus, as the raw materials 
are heated in the kiln, organic compounds can evolve from trace 
levels of organics in the raw materials. These organic compounds can 
be measured as hydrocarbons and, when only partially oxidized, 
carbon monoxide. This process is not related to combustion of 
hazardous waste or other fuels in the combustion zone at the other 
end of the kiln.
    \145\ Of course, if a source elects to comply with the carbon 
monoxide standard, then we are more assured of good combustion 
conditions in the combustion zone, and thus good control of organic 
hazardous air pollutants that could be potentially emitted from 
feeding hazardous waste in the combustion zone.
---------------------------------------------------------------------------

    Second, requiring continuous compliance with both a carbon monoxide 
and hydrocarbon emission limitation in the stack can be redundant for 
control of organic emissions from combustion of hazardous waste 
because: (1) Hydrocarbon alone is a direct and reliable surrogate for 
organic hazardous air pollutants; and (2) in most cases carbon monoxide 
is a conservative indicator of good combustion conditions and thus good 
control of organic hazardous air pollutants. As discussed in the 
following paragraphs, however, we have concluded that a source must 
demonstrate compliance with the hydrocarbon standard during the 
comprehensive performance test if it elects to continuously comply with 
the carbon monoxide standard to ensure that carbon monoxide is an 
adequate continuously monitored indicator of combustion efficiency. See 
Part Four, Section IV of the preamble for a discussion of the merits of 
using limits on stack gas concentrations of carbon monoxide and 
hydrocarbon to control organic emissions.
    One commenter suggested cement kilns be given the option to comply 
with a carbon monoxide limit of 100 ppmv instead of the 20 ppmv 
hydrocarbon limit. The commenter emphasized that this option is 
currently allowed under the RCRA boiler and industrial furnace 
regulations, and that it would be conservative because hydrocarbon 
levels would always be below 20 ppmv when carbon monoxide levels are 
below 100 ppmv. As discussed below, we agree that cement kilns should 
be given the option to comply with either standard, but do not agree 
that compliance with the carbon monoxide standard ensures compliance 
with the hydrocarbon standard.
    We have determined that it is necessary to require a source that 
elects to continuously comply with the carbon monoxide standard to also 
demonstrate compliance with the 20 ppmv hydrocarbon standard during the 
comprehensive performance test. We concluded that this requirement is 
necessary because we have limited data that shows a source can produce 
high hydrocarbon emissions while simultaneously producing low carbon 
monoxide emissions. This requirement to demonstrate compliance with the 
hydrocarbon standard during the performance test is sufficient to 
ensure that carbon monoxide alone is an appropriate continuously 
monitored indicator of combustion efficiency. See Part 4, Section IV.B, 
for a more detailed discussion. Consistent with this principle, 
incinerators and lightweight aggregate kilns are also required to 
demonstrate compliance with hydrocarbon standard during the 
comprehensive performance test if they elect to comply with the carbon 
monoxide standard.
    In today's final rule, we are identifying a carbon monoxide level 
of 100 ppmv and a hydrocarbon level of 20 ppmv as floor control for 
existing sources because they are currently enforceable Federal 
standards for hazardous waste burning cement kilns. See Sec. 266.104(b) 
and (c). As current rules allow, sources would have the option of 
complying with either limit. However, sources that elect to comply with 
the carbon monoxide standard must also demonstrate compliance with the 
hydrocarbon standard during the comprehensive performance test.
    Given that these are current RCRA rules, all cement kilns without 
by-pass sampling systems can currently achieve these emission levels. 
Thus, we estimate no emissions reductions (or new costs) for compliance 
with these floor levels.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the April 1996 proposal, we identified beyond-the-floor 
control levels for carbon monoxide and hydrocarbon in the main stack of 
50 ppmv and 6 ppmv, respectively. (See 61 FR at 17397.) These beyond-
the-floor levels were based on the use of a combustion gas afterburner. 
We indicated in the proposal, however, that the beyond-the-floor 
control was not practical since no kilns currently achieved these 
emission levels, and because of the high costs to retrofit a kiln with 
an afterburner.
    One commenter wrote that we rejected the 50 ppmv and 6 ppmv beyond-
the-floor carbon monoxide and hydrocarbon standards, respectively, 
without providing any justification. In order to confirm the reasoning 
discussed above, we have now estimated that the annualized cost for an 
afterburner for cement kilns will range from $3-8 million dollars per 
facility.\146\ As proposed, and as we reiterated in the May 1997 NODA a 
beyond-the-floor standard based on an afterburner would be not be cost-
effective due to the high retrofit costs and minimal incremental 
emissions reductions, and we do not adopt a beyond-the-floor standard 
for existing cement kilns.
---------------------------------------------------------------------------

    \146\ See `Final Technical Support Document for Hazardous Waste 
Combustor MACT Standards, Volume V: Emission Estimates and 
Engineering Costs'', February, 1999.
---------------------------------------------------------------------------

    In summary, we adopt the floor emission levels as standards for 
carbon monoxide, 100 ppmv, and hydrocarbons, 20 ppmv.
    c. What Is the MACT Floor for New Sources? In the April 1996 
proposal (see 61 FR at 17401) and the May 1997 NODA, we identified a 
new source hydrocarbon floor emission level of 20 ppmv for new cement 
kilns not equipped with by-pass sampling systems based on the current 
Federally-enforceable BIF standards. The hydrocarbon limit is based on 
control of organics in raw materials coupled with good combustion 
practices.
    In developing the final rule, we considered the comment discussed 
above that the rule should allow compliance with either a carbon 
monoxide standard of 100 ppmv or a hydrocarbon standard of 20 ppmv. 
Given that this option is available under the current BIF rule for new 
and existing sources, we now conclude that it represents MACT floor for 
new sources, except as discussed below.
    As discussed previously, we have also proposed MACT standards for 
nonhazardous waste burning cement kilns. See 63 FR 14182, March 24, 
1998. In that proposal, we determined that some existing sources have 
used the combination of feed material selection, site location, and 
feed material blending to optimize operations. We then concluded that 
site selection based on availability of acceptable raw material 
hydrocarbon content is a feasible approach to control hydrocarbon 
emissions at new sources. See 63 FR at 14202-03. We proposed a new 
source

[[Page 52887]]

floor hydrocarbon emission level of 50 ppmv at nonhazardous waste 
burning Portland cement kilns because it is being consistently achieved 
during thirty-day block averaging periods when high hydrocarbon content 
raw materials are avoided. We have since promulgated a standard of 50 
ppmv for hydrocarbons for new nonhazardous waste burning cement kilns. 
64 FR 31898.
    We now conclude for the same reasons that site selection is floor 
control for new source, greenfield hazardous waste burning cement kilns 
\147\ and that the floor hydrocarbon emission level is 50 ppmv.\148\ 
Sources must document compliance with this standard for each thirty-day 
block period of operation. We reconcile this hydrocarbon floor level of 
50 ppmv with the floor levels discussed above of 20 ppmv hydrocarbons 
or 100 ppmv carbon monoxide by establishing the floor as follows. For 
new source greenfield kilns, the floor is either: (1) 20 ppmv 
hydrocarbons; or (2) 100 ppmv carbon monoxide and 50 ppmv hydrocarbons. 
For other new sources not located at greenfield sites, the floor is 
either 20 ppmv hydrocarbons or 100 ppmv carbon monoxide, which is 
identical to the standards for existing sources.
---------------------------------------------------------------------------

    \147\ At least one hazardous waste burning cement kiln in our 
data base used raw material substitution to control hydrocarbon 
emissions.
    \148\ We concluded that this new source hydrocarbon standard of 
50 ppms should not apply to new sources that are not located at 
greenfield sites since these kilns are not capable of using site-
selection to control hydrocarbon emissions.
---------------------------------------------------------------------------

    The combined 20 ppmv hydrocarbon and 100 ppmv carbon monoxide 
standards control organic hazardous air pollutant emissions that 
originate from the incomplete combustion of hazardous waste. The 50 
ppmv hydrocarbon standard for new greenfield kilns controls organic 
hazardous air pollutant emissions that originate from the raw material. 
We conclude that the 50 ppmv hydrocarbon standard is necessary to deter 
new kilns from siting at locations that have on-site raw material that 
is high in organic content, since siting a cement kiln at such a 
location could result in elevated hydrocarbon emissions.
    We considered whether new greenfield kilns would be required to 
monitor hydrocarbons continuously, or just document compliance with the 
50 ppmv limit during the comprehensive performance test. We determined 
that hydrocarbons must be continuously monitored because compliance 
with the 100 ppmv carbon monoxide limit may not always ensure 
compliance with the 50 ppmv hydrocarbon limit. This is because 
hydrocarbons could potentially evolve from raw materials in the upper 
drying zone end of the kiln under conditions that inhibit sufficient 
oxidation of the hydrocarbons to form carbon monoxide.
    As with existing sources, we are requiring new sources that elect 
to continuously comply with the carbon monoxide standard, and new 
greenfield sources that elect to comply with the carbon monoxide and 50 
ppmv hydrocarbon standard, to also demonstrate compliance with the 20 
ppmv hydrocarbon standard during the comprehensive performance test. 
Consistent with this principle, incinerators and lightweight aggregate 
kilns are also required to demonstrate compliance with the hydrocarbon 
standard during the comprehensive performance test if they elect to 
comply with the carbon monoxide standard.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the April 1996 proposal, we identified beyond-the-floor emission levels 
for carbon monoxide and hydrocarbon of 50 ppmv and 6 ppmv, 
respectively, for new sources. (See 61 FR at 17401.) These beyond-the-
floor levels were based on the use of a combustion gas afterburner. We 
indicated in the proposal, however, that beyond-the-floor control was 
not practical since none of the kilns in our data base are achieving 
these emission levels, and because of the high costs to retrofit kilns 
with an afterburner. We reiterated in the May 1997 NODA that a beyond-
the-floor standard based on use of an afterburner would not be cost-
effective.
    One commenter supported these beyond-the-floor standards for new 
sources, but did not explain why these were considered to be 
appropriate standards. As discussed above for existing sources, we 
continue to believe that a beyond-the-floor standard based on use of an 
afterburner would not be cost-effective.
    In summary, we adopt the floor levels as standards for new sources. 
For new source greenfield kilns, the standard monitored continuously is 
either: (1) 20 ppmv hydrocarbons; or (2) 100 ppmv carbon monoxide and 
50 ppmv hydrocarbons. For other new source kilns, the standard is 
either 20 ppmv hydrocarbons or 100 ppmv carbon monoxide monitored 
continuously. New sources that elect to comply with the carbon monoxide 
standard, and new greenfield sources that elect to comply with the 
carbon monoxide and 50 ppmv hydrocarbon standard, must also demonstrate 
compliance with the 20 ppmv hydrocarbon standard, but only during the 
comprehensive performance test.
9. What Are the Carbon Monoxide and Hydrocarbon Standards for Kilns 
With By-Pass Sampling Systems? 149
---------------------------------------------------------------------------

    \149\ This also includes cement kilns which have midkiln 
sampling systems. See USEPA, ``Final Technical Support Document for 
Hazardous Waste Combustor MACT Standards, Volume I: Description of 
Source Categories,'' July 1999, for further explanation of by-pass 
and midkiln sampling systems.
---------------------------------------------------------------------------

    See Sec. 63.1204(a)(5) and (b)(5).
    We establish carbon monoxide and hydrocarbon standards for existing 
and new cement kilns with by-pass sampling systems as surrogates to 
control emissions of nondioxin organic hazardous air 
pollutants.150 Existing kilns are required to comply with 
either a carbon monoxide standard of 100 ppmv or a hydrocarbon standard 
of 10 ppmv on an hourly rolling average basis. Both standards apply to 
combustion gas sampled in the by-pass or a midkiln sampling port that 
samples representative kiln gas. Sources that elect to comply with the 
carbon monoxide standard, however, must also document compliance with 
the hydrocarbon standard during the comprehensive performance 
test.151 See Part Four, Section IV.B of the preamble for the 
rationale for this requirement.
---------------------------------------------------------------------------

    \150\ As discussed in Part 5, Section X.F, cement kilns equipped 
with bypass sampling systems that feed hazardous waste at a location 
other than the end where products are normally discharged and at a 
location downstream of the bypass sampling location (relative to the 
combustion gas flow direction) must comply with the 20 ppmv main 
stack hydrocarbon standard discussed in the previous section in lieu 
of the bypass gas hydrocarbon standard.
    \151\As discussed in Part 5, Section X.F, cement kilns that feed 
hazardous waste at a location other than the end where products are 
normally discharged and where fuels are normally fired must comply 
wit the 10 ppmv hydrocarbon standard (i.e., these sources do not 
have the option to comply with the carbon monoxide standard).
---------------------------------------------------------------------------

    New kilns are subject to the same by-pass gas carbon monoxide and 
hydrocarbon standards as existing sources. But, new, greenfield 
152 kilns must also comply with a 50 ppmv hydrocarbon 
standard continuously monitored in the main stack. Sources must 
document compliance with this standard for each thirty-day block period 
of operation.
---------------------------------------------------------------------------

    \152\ A greenfield cement kiln is a kiln that commenced 
construction or reconstruction after April 19, 1996 at a site where 
no cement kiln previously existed, irrespective of the class of kiln 
(i.e., nonhazardous waste or hazardous waste burning). A newly 
constructed or reconstructed cement kiln at an existing site would 
not be classified as a greenfield cement kiln, and would be subject 
to the same carbon monoxide and hydrocarbon standards as an existing 
cement kiln.
---------------------------------------------------------------------------

    We discuss the rationale for adopting these standards below.

[[Page 52888]]

    a. What Is the MACT Floor for Existing Sources? In the April 1996 
proposal, we identified floor carbon monoxide and hydrocarbon emission 
standards for by-pass gas of 100 ppmv and 6.7 ppmv, respectively. Floor 
control was good combustion practices. (See 61 FR at 17397.) In the May 
1997 NODA, we used an alternative data analysis method to identify a 
hydrocarbon floor level of 10 ppmv.153 See 62 FR at 24230. 
Our decision to use engineering information and principles to set the 
proposed floor standard was based, in part, on the limited hydrocarbon 
data in our data base. In addition, we reasoned that the hydrocarbon 
levels being achieved in an incinerator, (i.e., 10 ppmv) are also being 
achieved in a cement kiln's by-pass duct.154
---------------------------------------------------------------------------

    \153\ The proposed hydrocarbon standard of 6.7 ppmv was based on 
a statistical and breakpoint analysis. Today's final rule, 
consistent with May 1997 NODA, instead uses engineering information 
and principles to identify the floor hydrocarbon level of 10 ppmv.
    \154\ See USEPA, ``Final Technical Support Document for 
Hazardous Waste Combustor MACT Standards, Volume III: Selection of 
MACT Standards and Technologies,'' February, 1999.
---------------------------------------------------------------------------

    Some commenters stated that we did not have sufficient hydrocarbon 
emissions data from cement kilns equipped with by-pass sampling systems 
to justify a by-pass duct hydrocarbon standard. We disagree and 
conclude that we have adequate data because the MACT data base includes 
seven cement kilns that monitored hydrocarbons at the bypass sampling 
location. These sources are achieving hydrocarbon levels of 10 ppmv or 
less.155 The fact that these sources achieve hydrocarbon 
levels below 10 ppmv supports our use of engineering information and 
principles to set the floor limit at 10 ppmv.156
---------------------------------------------------------------------------

    \155\ Four of these kilns have ceased hazardous waste 
operations, and one of the kilns collected that data during time 
periods other than Certification of Compliance testing.
    \156\ We note that we could have elected to establish this 10 
ppmv hydrocarbon standard as a beyond-the-floor standard rather than 
a floor standard.
---------------------------------------------------------------------------

    Many commenters questioned whether cement kilns with by-pass 
sampling systems should comply with both a hydrocarbon and carbon 
monoxide standard. Those in favor of requiring cement kilns to comply 
with both standards wrote that neither carbon monoxide nor hydrocarbons 
are sufficient surrogates for organic hazardous air pollutant 
emissions. Commenters also noted that by requiring both a carbon 
monoxide and hydrocarbon limit, we would achieve appropriate organic 
hazardous air pollutant emission reductions. Other commenters wrote 
that continuous compliance with both a hydrocarbon and a carbon 
monoxide standard would be redundant and unnecessarily costly. We agree 
with the latter view, in that requiring continuous compliance with both 
standards for bypass gas is redundant for control of organic emissions 
from combustion of hazardous waste because, as previously discussed: 
(1) Hydrocarbon alone is a direct and reliable surrogate for organic 
hazardous air pollutants; and (2) in most cases, carbon monoxide is a 
conservative indicator of good combustion conditions and thus good 
control of organic hazardous air pollutants. However, as discussed 
earlier, we have concluded that a source must demonstrate compliance 
with the hydrocarbon standard during the comprehensive performance test 
if it elects to continuously comply with the carbon monoxide standard 
to ensure that carbon monoxide is an adequate continuously monitored 
indicator of combustion efficiency. See discussion in Part Four, 
Section IV.B of the preamble for more discussion on this issue.
    One commenter stated that due to some by-pass gas quenching 
methods, and the need to correct for moisture and oxygen, it may not be 
possible to accurately measure hydrocarbons to the level of the 
proposed standard, i.e., 6.7 ppmv. We disagree with this reasoning 
because, as explained in the technical support document, cement kiln 
by-pass hydrocarbon levels should be reasonably achievable and 
measurable by decreasing the span and increasing the calibration 
frequency of the hydrocarbon monitor.157 We also note that a 
cement kiln has the option to petition the Administrator for 
alternative monitoring approaches under Sec. 63.8(f) if the source has 
valid reasons why a total hydrocarbon monitor cannot be used to 
document compliance.
---------------------------------------------------------------------------

    \157\ See USEPA, ``Final Technical Support Document for 
Hazardous Waste Combustor MACT Standards, Volume III: Selection of 
MACT Standards and Technologies,'' February, 1999.
---------------------------------------------------------------------------

    We conclude that floor control can achieve by-pass gas emission 
levels of 100 ppmv for carbon monoxide and 10 ppmv for hydrocarbons. As 
discussed in Part Four, Section IV.B, a source may comply with either 
standard. If the source elects to comply with the carbon monoxide 
standard, however, it must also demonstrate compliance with the 
hydrocarbon standard during comprehensive performance testing.
    We estimate that all cement kilns with by-pass sampling systems can 
currently achieve the carbon monoxide floor of 100 ppmv. We also 
estimate that approximately 97 percent of cement kilns with by-pass 
sampling systems meet the hydrocarbon floor level of 10 ppmv. The 
national annualized compliance cost for cement kilns to comply with the 
floor level is $37K and hydrocarbon emissions will be reduced by 11 Mg/
yr, two percent from current baseline emissions .
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the April 1996 proposal, we identified a beyond-the-floor 
control level for carbon monoxide and hydrocarbons in the main stack of 
50 ppmv and 6 ppmv, respectively, based on the use of a combustion gas 
afterburner. (See 61 FR at 17399.) We indicated in the proposal that 
this beyond-the-floor level was not practical, however, since none of 
the kilns currently achieve these emission levels and because of the 
high costs of retrofitting kilns with an afterburner. We estimate that 
the annualized cost for each cement kiln to operate afterburners range 
from three to eight million dollars.158 We continue to 
believe that it is not cost-effective based on the high retrofit costs 
and minimal incremental emissions reductions to adopt these beyond-the-
floor standards.
---------------------------------------------------------------------------

    \158\ See ``Final Technical Support Document for Hazardous Waste 
Combustor MACT Standards, Volume V: Emission Estimates and 
Engineering Costs'', February, 1999.
---------------------------------------------------------------------------

    In the April 1996 NPRM, we also considered limiting main stack 
hydrocarbon emissions to a beyond-the-floor level of 20 ppmv based on 
the use of a low-organic raw material.159 This was in 
addition to floor controls limiting carbon monoxide and/or hydrocarbon 
levels in the by-pass. See 61 FR at 17398. We considered this beyond-
the-floor option to address concerns that: (1) organics desorbed from 
raw materials may contain hazardous air pollutants, even absent any 
influence from burning hazardous waste; and, (2) it is reasonable to 
hypothesize that the chlorine released from burning hazardous waste can 
react with the organics desorbed from the raw material to form 
generally more toxic chlorinated hazardous air pollutants. Many 
commenters supported this approach. For the reasons discussed below, 
however, we conclude it is not appropriate to adopt this beyond-the-

[[Page 52889]]

floor hydrocarbon standard for existing sources.
---------------------------------------------------------------------------

    \159\ The definition of floor control for existing cement kilns 
equipped with by-pass sampling systems does not include the use of 
low organic raw material. Although we have limited data indicating 
that some kilns used low organic raw material to control hydrocarbon 
emissions, there are enough facilities using this method of control 
to establish it as a floor control for existing sources.
---------------------------------------------------------------------------

    Also, many commenters stated that we should establish a main stack 
hydrocarbon standard because, as stated above, hazardous waste 
combustion byproducts from cement kilns, particularly chlorine, can 
react with organic compounds desorbed from raw materials to form 
hazardous air pollutants. Commenters believe that an additional main 
stack hydrocarbon emission standard would limit the emissions of 
chlorinated organic hazardous air pollutants that are generated due to 
the interaction of the hazardous waste combustion byproducts and the 
organics desorbed from the raw material.
    We disagree that a main stack hydrocarbon emission limit is an 
appropriate beyond-the-floor control for existing sources. First, we do 
not believe it is cost-effective to require an existing kiln to 
substitute its raw material with an off-site raw 
material.160 Cement kilns are sited proximate to the primary 
raw material supply and transporting large quantities of an alternative 
source of raw material(s) is likely to be very costly. Second, 
establishing a main stack hydrocarbon limit for existing sources is 
likely to be counter-productive in controlling organic hazardous air 
pollutants. It may compel the operator to avoid the unacceptable costs 
of importing low organic raw material by increasing back-end kiln 
temperatures to oxidize organics desorbed from raw material, thus 
lowering hydrocarbon levels. This increase in temperature may result in 
increased dioxin formation and is counter to our dioxin control 
strategy. Third, it is debatable whether there is a strong relationship 
between chlorine feedrates and chlorinated organic hazardous air 
pollutant emissions, as is suggested by commenters.161 
Finally, we anticipate that any potential risks associated with the 
possible formation of these chlorinated hazardous air pollutants at 
high hydrocarbon emission levels can be adequately addressed in a site-
specific risk assessment conducted as part of the RCRA permitting 
process. This increased potential for emissions of chlorinated 
hazardous air pollutants is not likely to warrant evaluation via a 
site-specific risk assessment under RCRA, however, unless main stack 
hydrocarbon levels are substantially higher than the 20 ppmv limit 
currently applicable under RCRA for cement kilns not equipped with by-
pass systems.
---------------------------------------------------------------------------

    \160\ We did not quantify actual costs associated with raw 
material substitution due to the lack of information.
    \161\ It is true that some studies have shown a relationship 
between chlorine levels in the flue gas and the generation of 
chlorobenzene in cement kiln emissions: the more chlorine, the more 
chlorobenzene is generated. Some full-scale tests, however, have 
shown that there is no observable or consistent trend when comparing 
``baseline'' (i.e., nonhazardous waste operation) organic hazardous 
air pollutant emissions with organic hazardous air pollutant 
emissions associated with hazardous waste operations, as well as 
comparing hazardous waste conditions with varying levels of 
chlorine. See USEPA, ``Final Technical Support Document for 
Hazardous Waste Combustor MACT Standards, Volume III: Selection of 
MACT Standards and Technologies,'' July 1999, for further 
discussion.
---------------------------------------------------------------------------

    In summary, we adopt the floor levels as standards for carbon 
monoxide, 100 ppmv, and hydrocarbons, 10 ppmv. As discussed above, a 
source may comply with either standard. If the source elects to comply 
with the carbon monoxide standard, however, it must also demonstrate 
compliance with the hydrocarbon standard during comprehensive 
performance testing.
    c. What Is the MACT Floor for New Sources? In the April 1996 
proposal, we identified new source floor standards for carbon monoxide 
and hydrocarbon emissions in the by-pass of 100 ppmv and 6.7 ppmv, 
respectively. We identified good combustion practices as floor control. 
(See 61 FR at 17401.) In the May 1997 NODA, we used an alternative data 
analyses method, in part, to identify an alternative new source 
hydrocarbon floor level. (See 62 FR at 24230.) As a result of this 
analysis and the use of engineering information and principles, we 
identified a floor hydrocarbon emission level of 10 ppmv in the by-pass 
for new cement kilns. We continue to believe that the new source 
hydrocarbon floor methodology discussed in the May 1997 NODA, and the 
new source carbon monoxide floor methodology discussed in the April 
1996 proposal, are appropriate. Therefore, we adopt these floor 
emission levels for by-pass gas in today's final rule.
    We also establish a 50 ppmv hydrocarbon floor level for the main 
stack of new greenfield kilns. As discussed above (Part Four, Section 
VII.8.c), we concluded during development of the final rule that some 
cement kilns are currently controlling their feed material selection, 
site location, and feed material blending to optimize operations. 
Because these controls can be used to control hydrocarbon content of 
the raw material and, thus, hydrocarbon emissions in the main stack, 
they represent floor control for main stack hydrocarbons for new 
sources.162 We established a floor hydrocarbon emission 
level of 50 ppmv because it is being consistently achieved during 
thirty-day block averaging periods when high hydrocarbon content raw 
materials are avoided.
---------------------------------------------------------------------------

    \162\ At least one hazardous waste burning cement kiln in our 
data base used raw material substitution to control hydrocarbon 
emissions.
---------------------------------------------------------------------------

    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the April 1996 proposal, we identified main stack beyond-the-floor 
emission levels for carbon monoxide and hydrocarbon of 50 ppmv and 6 
ppmv, respectively, for new sources. (See 61 FR at 17401.) These 
beyond-the-floor levels were based on the use of a combustion gas 
afterburner. We indicated in the proposal, however, that beyond-the-
floor control was not practical since none of the kilns in our data 
base are achieving these emission levels, and because of the high costs 
to retrofit kilns with an afterburner. We reiterated in the May 1997 
NODA, that a beyond-the-floor standard based on use of an afterburner 
would not be cost-effective.
    One commenter wrote that we rejected these beyond-the-floor carbon 
monoxide and hydrocarbon standards without providing any justification. 
Another commenter supported these beyond-the-floor standards for new 
sources. As discussed above (in greater detail) for existing sources, 
we continue to believe that a beyond-the-floor standard based on use of 
an afterburner would not be cost-effective.
    In the April 1996 proposal, we considered limiting main stack 
hydrocarbon emissions at new sources equipped with by-pass sampling 
systems to a beyond-the-floor level of 20 ppmv.163 This 
addressed concerns that: (1) Organics desorbed from raw materials 
contain hazardous air pollutants, even absent any influence from 
burning hazardous waste; and (2) it is reasonable to hypothesize that 
the chlorine released from burning hazardous waste can react with the 
organics desorbed from the raw material to form generally more toxic 
chlorinated hazardous air pollutants. Although not explicitly stated, 
beyond-the-floor control would have been control of feed material 
selection, site location, and feed material blending to control the 
hydrocarbon content of the raw material and, thus, hydrocarbon 
emissions in the main stack. As discussed above, however, we adopt 
today a main stack hydrocarbon floor standard of 50 ppmv for newly 
constructed greenfield cement kilns equipped with by-pass systems. We 
are not adopting a main stack beyond-the floor hydrocarbon standard of 
20 ppmv for these kilns because we

[[Page 52890]]

are concerned that it may not be readily achievable using beyond-the-
floor control.
---------------------------------------------------------------------------

    \163\ This was in addition to limiting hydrocarbon and/or carbon 
monoxide at the by-pass sampling location.
---------------------------------------------------------------------------

    In summary, we establish the following standards for new sources 
based on floor control: (1) By-pass gas emission standards for carbon 
monoxide and hydrocarbons of 100 ppmv and 10 ppmv, respectively; 
164 and (2) a main stack hydrocarbon standard of 50 ppmv at 
greenfield sites.
---------------------------------------------------------------------------

    \164\ A source may comply with either bypass gas standard. If 
the source elects to comply with the carbon monoxide standard, 
however, it must also demonstrate compliance with the hydrocarbon 
standard during comprehensive performance testing.
---------------------------------------------------------------------------

10. What Are the Destruction and Removal Efficiency Standards?
    We establish a destruction and removal efficiency (DRE) standard 
for existing and new cement kilns to control emissions of organic 
hazardous air pollutants other than dioxins and furans. Dioxins and 
furans are controlled by separate emission standards. See discussion in 
Part Four, Section IV.A. The DRE standard is necessary, as previously 
discussed, to complement the carbon monoxide and hydrocarbon emission 
standards, which also control these hazardous air pollutants.
    The standard requires 99.99 percent DRE for each principal organic 
hazardous constituent (POHC), except that 99.9999 percent DRE is 
required if specified dioxin-listed hazardous wastes are burned. These 
wastes are listed as--F020, F021, F022, F023, F026, and F027--RCRA 
hazardous wastes under part 261 because they contain high 
concentrations of dioxins.
    a. What Is the MACT Floor for Existing Sources? Existing sources 
are currently subject to DRE standards under Sec. 266.104(a) that 
require 99.99 percent DRE for each POHC, except that 99.9999 percent 
DRE is required if specified dioxin-listed hazardous wastes are burned. 
Accordingly, these standards represent MACT floor. Since all hazardous 
waste cement kilns are currently subject to these DRE standards, they 
represent floor control, i.e., greater than 12 percent of existing 
sources are achieving these controls.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? Beyond-the-floor control would be a requirement to achieve a 
higher percentage DRE, for example, 99.9999 percent DRE for POHCs for 
all hazardous wastes. A higher DRE could be achieved by improving the 
design, operation, or maintenance of the combustion system to achieve 
greater combustion efficiency.
    Sources will not incur costs to achieve the 99.99% DRE floor 
because it is an existing RCRA standard . A substantial number of 
existing hazardous waste combustors are not likely to be routinely 
achieving 99.999% DRE, however, and most are not likely to be achieving 
99.9999% DRE. Improvements in combustion efficiency will be required to 
meet these beyond-the-floor DREs. Improved combustion efficiency is 
accomplished through better mixing, higher temperatures, and longer 
residence times. As a practical matter, most combustors are mixing-
limited. Thus, improved mixing is necessary for improved DREs. For a 
less-than-optimum burner, a certain amount of improvement may typically 
be accomplished by minor, relatively inexpensive combustor 
modifications--burner tuning operations such as a change in burner 
angle or an adjustment of swirl--to enhance mixing on the macro-scale. 
To achieve higher and higher DREs, however, improved mixing on the 
micro-scale may be necessary requiring significant, energy intensive 
and expensive modifications such as burner redesign and higher 
combustion air pressures. In addition, measurement of such DREs may 
require increased spiking of POHCs and more sensitive stack sampling 
and analysis methods at added expense.
    Although we have not quantified the cost-effectiveness of a beyond-
the-floor DRE standard, we do not believe that it would be cost-
effective. For reasons discussed above, we believe that the cost of 
achieving each successive order-of-magnitude improvement in DRE will be 
at least constant, and more likely increasing. Emissions reductions 
diminish substantially, however, with each order of magnitude 
improvement in DRE. For example, if a source were to emit 100 gm/hr of 
organic hazardous air pollutants assuming zero DRE, it would emit 10 
gm/hr at 90 percent DRE, 1 gm/hr at 99 percent DRE, 0.1 gm/hr at 99.9 
percent DRE, 0.01 gm/hr at 99.99 percent DRE, and 0.001 gm/hr at 99.999 
percent DRE. If the cost to achieve each order of magnitude improvement 
in DRE is roughly constant, the cost-effectiveness of DRE decreases 
with each order of magnitude improvement in DRE. Consequently, we 
conclude that this relationship between compliance cost and diminished 
emissions reductions associated with a more stringent DRE standard 
suggests that a beyond-the-floor standard is not warranted.
    c. What Is the MACT Floor for New Sources? The single best 
controlled source, and all other hazardous waste cement kilns, are 
subject to the existing RCRA DRE standard under Sec. 266.104(a). 
Accordingly, we adopt this standard as the MACT floor for new sources.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? As 
discussed above, although we have not quantified the cost-effectiveness 
of a more stringent DRE standard, diminishing emissions reductions with 
each order of magnitude improvement in DRE suggests that cost-
effectiveness considerations would likely come into play. We conclude 
that a beyond-the-floor standard is not warranted.

VIII. What Are the Standards for Existing and New Hazardous Waste 
Burning Lightweight Aggregate Kilns?

A. To Which Lightweight Aggregate Kilns Do Today's Standards Apply?
    The standards promulgated today apply to each existing, 
reconstructed, and newly constructed lightweight aggregate plant where 
hazardous waste is burned in the kiln. These standards apply to major 
source and area source lightweight aggregate facilities. Lightweight 
aggregate kilns that do not engage in hazardous waste burning 
operations are not subject to this NESHAP; however, these kilns will be 
subject to future MACT standards for the Clay Products source category.
B. What Are the Standards for New and Existing Hazardous Waste Burning 
Lightweight Aggregate Kilns?
1. What Are the Standards for Lightweight Aggregate Kilns?
    In this section, the basis for the emissions standards for 
hazardous waste burning lightweight aggregate kilns is discussed. The 
kiln emission limits apply to the kiln stack gases from lightweight 
aggregate plants that burn hazardous waste. The emissions standards are 
summarized below:

[[Page 52891]]



       Standards for Existing and New Lightweight Aggregate Kilns
------------------------------------------------------------------------
 Hazardous air pollutant or             Emissions standard \1\
   hazardous air pollutant   -------------------------------------------
          surrogate             Existing sources         New sources
------------------------------------------------------------------------
Dioxin/furan................  0.20 ng TEQ/dscm; or  0.20 ng TEQ/dscm; or
                               0.40 ng TEQ/dscm      0.40 ng TEQ/dscm
                               and rapid quench of   and rapid quench of
                               the flue gas at the   the flue gas at the
                               exit of the kiln to   exit of the kiln to
                               less than 400 deg.F.  less than 400
                                                     deg.F.
Mercury.....................  47 g/dscm..  43 g/dscm.
Particulate matter..........  57 mg/dscm (0.025 gr/ 57 mg/dscm (0.025 gr/
                               dscf).                dscf).
Semivolatile metals \2\.....  250 g/dscm.  43 g/dscm.
Low volatile metals \3\.....  110 g/dscm.  110 g/dscm.
Hydrochloric acid/chlorine    230 ppmv............  41 ppmv.
 gas.
Hydrocarbons 2,3............  20 ppmv (or 100 ppmv  20 ppmv (or 100 ppmv
                               carbon monoxide).     carbon monoxide).
Destruction and removal        For existing and new sources, 99.99% for
 efficiency.                        each principal organic hazardous
                                   constituent (POHC) designated. For
                                 sources burning hazardous wastes F020,
                               F021, F022, F023, F026, or F027, 99.9999%
                                       for each POHC designated.
------------------------------------------------------------------------
\1\ All emission levels are corrected to 7% O2, dry basis.
\2\ Hourly rolling average. Hydrocarbons are reported as propane.
\3\ Lightweight aggregate kilns that elect to continuously comply with
  the carbon monoxide standard must demonstrate compliance with the
  hydrocarbon standard of 20 ppmv during the comprehensive performance
  test.

2. What Are the Dioxin and Furan Standards?
    In today's rule, we establish a standard for new and existing 
lightweight aggregate kilns that limits dioxin/furan emissions to 
either 0.20 ng TEQ/dscm; or 0.40 ng TEQ/dscm and rapid quench of the 
flue gas at the exit of the kiln to less than 400 deg.F. Our rationale 
for adopting these standards is discussed below.
    a. What Is the MACT Floor for Existing Sources? In the April 1996 
proposal, we had dioxin/furan emissions data from only one lightweight 
aggregate kiln and pooled that data with the dioxin/furan data for 
hazardous waste burning cement kilns to identify the MACT floor 
emission level. We stated that it is appropriate to combine the two 
data sets because they are adequately representative of general dioxin/
furan behavior and control in either type of kiln. Consequently, floor 
control and the floor emission level for lightweight aggregate kilns 
were the same as for cement kilns. We proposed a floor emission level 
of 0.20 ng TEQ/dscm, or temperature at the inlet to the fabric filter 
not to exceed 418 deg.F. (61 FR at 17403.)
    Several commenters opposed our proposed approach of pooling the 
lightweight aggregate kiln data with the cement kiln dioxin/furan data 
for the MACT floor analysis. In order to respond to commenter concerns, 
we obtained additional dioxin/furan emissions data from lightweight 
aggregate kiln sources. In a MACT reevaluation discussed in the May 
1997 NODA, we presented an alternative data analysis method to identify 
floor control and the floor emission level. In that NODA, dioxin/furan 
floor control was defined as temperature control not to exceed 
400 deg.F at the inlet to the fabric filter. That analysis resulted in 
a floor emission level of 0.20 ng TEQ/dscm, or 4.1 ng TEQ/dscm and 
temperature at the inlet to the fabric filter not to exceed 400 deg.F. 
(62 FR at 24231.) An emission level of 4.1 ng TEQ/dscm represents the 
highest single run from the test condition with the highest run 
average. We concluded that 4.1 ng TEQ/dscm was a reasonable floor 
level, from an engineering perspective, given our limited dioxin/furan 
data base for lightweight aggregate kilns. (We noted that if this were 
a large data set, we would have identified the floor emission level 
simply as the highest test condition average.) Due to variability among 
the runs of the test condition with the highest condition average and 
because a floor level of 4.1 ng TEQ/dscm is 40 percent higher than the 
highest test condition average of 2.9 ng TEQ/dscm lightweight aggregate 
kilns using floor control will be able to meet routinely a floor 
emission level of 4.1 ng TEQ/dscm.
    We maintain that the floor methodology discussed in the May 1997 
NODA is appropriate and we adopt this approach in today's rule. In that 
NODA we identified two technologies for control of dioxin/furan 
emissions from lightweight aggregate kilns. The first technology 
controls dioxin/furans by quenching kiln gas temperatures at the exit 
of the kiln so that gas temperatures at the inlet to the particulate 
matter control device are below the temperature range of optimum 
dioxin/furan formation. The other technology is activated carbon 
injected into the kiln exhaust gas. Because activated carbon injection 
is not currently used by any hazardous waste burning lightweight 
aggregate kilns, this technology was evaluated only as part of a 
beyond-the-floor analysis.
    One commenter opposes our approach specifying a MACT floor control 
temperature limitation of 400 deg.F at the particulate matter control 
device. Instead, the commenter supports a temperature limitation of 
417 deg.F, which is the highest temperature associated with any dioxin/
furan test condition in our data base. Although only two of the three 
test conditions for which we have dioxin/furan emissions data operated 
the fabric filter at 400 deg.F or lower (the third operated at 
417 deg.F), we do have other fabric filter operating temperatures from 
kilns performing RCRA compliance testing for other hazardous air 
pollutants that document fabric filter operations at 400 deg.F or 
lower. From these data, we conclude that lightweight aggregate kilns 
can operate the fabric filter at temperatures of 400 deg.F or lower. 
Thus, identifying floor control at a temperature limitation of 
400 deg.F ensures that all lightweight aggregate kilns will be 
operating consistent with sound operational practices for controlling 
dioxin/furan emissions.
    As discussed in the May 1997 NODA, specifying a temperature 
limitation of 400 deg.F or lower is appropriate for floor control 
because, from an engineering perspective, it is within the range of 
reasonable values that could have been selected considering that: (1) 
The optimum temperature window for surface-catalyzed dioxin/furan 
formation is approximately 450-750 deg.F; and (2) temperature levels 
below 350 deg.F can cause dew point condensation problems resulting in 
particulate matter control device corrosion. Further, lightweight 
aggregate kilns can operate at air pollution control device 
temperatures between 350 to 400 deg.F. In

[[Page 52892]]

fact, all lightweight aggregate kilns use (or have available) fabric 
filter ``tempering'' air dilution and water quench for cooling kiln 
exit gases prior to the fabric filter (some kilns also augment this 
with uninsulated duct radiation cooling). Thus, the capability of 
operating fabric filters at temperatures lower than 400 deg.F currently 
exists and is practical. See the technical support document for further 
discussion.165
---------------------------------------------------------------------------

    \165\ USEPA, ``Final Technical Support document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    In summary, today's floor emission level for dioxin/furan emissions 
for existing lightweight kilns is 0.20 ng TEQ/dscm or 4.1 ng TEQ/dscm 
and control of temperature at the inlet to the fabric filter not to 
exceed 400 deg.F. We estimate that all lightweight aggregate kiln 
sources currently are meeting the floor level.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? We considered in the April 1996 proposal a beyond-the-floor 
standard of 0.20 ng TEQ/dscm based on injection of activated carbon at 
a flue gas temperature of less than 400 deg.F. (61 FR at 17403.) In the 
May 1997 NODA, we considered a beyond-the-floor standard of 0.20 ng 
TEQ/dscm standard based on rapidly quenching combustion gases at the 
exit of the kiln to 400 deg.F, and insulating the duct-work between the 
kiln exit and the fabric filter to maintain gas temperatures high 
enough to avoid dew point problems. (62 FR at 24232.)
    One commenter, however, disagrees that there is adequate evidence 
(test data) supporting rapid quench of kiln exit gases to less than 
400 deg.F can achieve a level of 0.20 ng TEQ/dscm. Based on these NODA 
comments and upon closer analysis of all available data, we find that a 
level of 0.20 ng TEQ/dscm has not been clearly demonstrated for 
lightweight aggregate kilns with rapid quench less than 400 deg.F prior 
to the particulate matter control device. The data show that some 
lightweight aggregate kilns can achieve a level of 0.20 TEQ ng/dscm 
with rapid quench. In addition, one commenter, who operates two 
lightweight aggregate kilns with heat exchangers that cool the flue gas 
to a temperature of approximately 400 deg.F at the fabric filter, 
stated that they achieve dioxin/furan emissions slightly below 0.20 ng 
TEQ/dscm. However, because of the small dioxin/furan data base we are 
concerned that these limited data may not show the full range of 
emissions. Due to the similarity of dioxin/furan control among cement 
kilns and lightweight aggregate kilns, we looked to the cement kiln 
data to complement our limited lightweight aggregate kiln dataset. As 
discussed earlier, cement kilns are able to control dioxin/furans to 
0.40 ng TEQ/dscm with temperature control. Since we do not expect a 
lightweight aggregate kiln to achieve lower dioxin/furan emissions than 
a cement kiln with rapid quench, we agree with these commenters and 
conclude that lightweight aggregate kilns can control dioxin/furans to 
0.40 ng TEQ/dscm with rapid quench of kiln exit gases to less than 
400 deg.F.
    Thus, for the final rule, we considered two beyond-the-floor 
levels: (1) Either 0.20 ng TEQ/dscm; or 0.40 ng TEQ/dscm and rapid 
quench of the kiln exhaust gas to a temperature less than 400 deg.F; 
and (2) a level of 0.20 ng TEQ/dscm based on activated carbon 
injection.
    The first option is a beyond-the-floor standard of either 0.20 ng 
TEQ/dscm, or 0.40 ng TEQ/dscm and rapid quench of the kiln exhaust gas 
to less than 400 deg.F. The national incremental annualized compliance 
cost for lightweight aggregate kilns to meet this beyond-the-floor 
level rather than comply with the floor controls would be approximately 
$50,000 for the entire hazardous waste burning lightweight aggregate 
kiln industry, and would provide an incremental reduction in dioxin/
furan emissions beyond the MACT floor controls of nearly 2 g TEQ/yr.
    Based on these costs of approximately $25 thousand per additional g 
of dioxin/furan removed and on the significant reduction in dioxin/
furan emissions achieved, we have determined that this dioxin/furan 
beyond-the-floor option for lightweight aggregate kilns is justified, 
especially given our special concern about dioxin/furans. Dioxin/furans 
are some of the most toxic compounds known due to their bioaccumulation 
potential and wide range of health effects, including carcinogenesis, 
at exceedingly low doses. Exposure via indirect pathways is a chief 
reason that Congress singled out dioxin/furans for priority MACT 
control in section 112(c)(6) of the CAA. See S. Rep. No. 128, 101st 
Cong. 1st Sess. at 154-155.
    We also evaluated, but rejected, activated carbon injection as a 
beyond-the-floor option. Carbon injection is routinely effective at 
removing 99 percent of dioxin/furans at numerous municipal waste 
combustor and medical waste combustor applications and one hazardous 
waste incinerator application. However, no hazardous waste burning 
lightweight aggregate kiln currently uses activated carbon injection 
for dioxin/furan removal. We believe that it is conservative to assume 
that only 95 percent is achievable given potential uncertainties in its 
application to lightweight aggregate kilns. In addition, we assumed for 
cost-effectiveness calculations that lightweight aggregate kilns 
needing activated carbon injection would install the activated carbon 
injection system after the existing fabric filter device and add a new 
smaller fabric filter to remove the injected carbon with the absorbed 
dioxin/furans and mercury. This costing approach addresses commenter's 
concerns that injected carbon may interfere with current dust recycling 
practices.
    The national incremental annualized compliance cost for lightweight 
aggregate kilns to meet a beyond-the-floor level based on activated 
carbon injection rather than comply with the floor controls would be 
approximately $1.2 million for the entire hazardous waste burning 
lightweight aggregate kiln industry. This would provide an incremental 
reduction in dioxin/furan emissions beyond the MACT floor controls of 
2.2 g TEQ/yr, or 90 percent. Based on these costs of approximately 
$0.53 million per additional g of dioxin/furan removed and the small 
incremental dioxin/furan emissions reduction beyond the dioxin/furan 
beyond-the-floor option discussed above (2.0 g TEQ/yr versus 2.2 g TEQ/ 
yr), we have determined that this second beyond-the-floor option for 
lightweight aggregate kilns is not justified. Therefore, we are not 
promulgating a beyond-the-floor standard of 0.20 ng TEQ/dscm for 
lightweight aggregate kilns based on activated carbon injection.
    Thus, the promulgated dioxin/furan standard for existing 
lightweight aggregate kilns is a beyond-the-floor standard of 0.20 ng 
TEQ/dscm; or 0.40 ng TEQ/dscm and rapid quench to a temperature not to 
exceed 400 deg.F based on rapid quench of flue gas at the exit of the 
kiln.
    c. What Is the MACT Floor for New Sources? In the April 1996 
proposal, the floor analysis for new lightweight aggregate kilns was 
the same as for existing kilns, and the proposed standard was the same. 
The proposed floor emission level was 0.20 ng TEQ/dscm, or temperature 
at the inlet to the particulate matter control device not to exceed 
418 deg.F. (61 FR at 17408.) In the May 1997 NODA, we used an 
alternative data analysis method to identify floor control and the 
floor emission level. As done for existing sources, floor control for 
new sources was defined as temperature control at the inlet to the 
particulate matter control device to less than 400 deg.F. That

[[Page 52893]]

analysis resulted in a floor emission level of 0.20 ng TEQ/dscm, or 4.1 
ng TEQ/dscm and temperature at the inlet to the fabric filter not to 
exceed 400 deg.F. Our engineering evaluation indicated that the best 
controlled source is one that is controlling temperature control at the 
inlet to the fabric filter at 400 deg.F. (62 FR at 24232.) We continue 
to believe that the floor methodology discussed in the May 1997 NODA is 
appropriate for new sources and we adopt this approach in the final 
rule. The floor level for new lightweight aggregate kilns is 0.20 ng 
TEQ/dscm, or 4.1 ng TEQ/dscm and temperature at the inlet to the 
particulate matter control device not to exceed 400 deg.F.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the April 1996 proposal, we proposed activated carbon injection as 
beyond-the-floor control and a beyond-the-floor standard of 0.20 ng 
TEQ/dscm. (61 FR at 17408.) In the May 1997 NODA, we identified a 
beyond-the-floor standard of 0.20 ng TEQ/dscm based on rapid quench of 
kiln gas to less than 400 deg.F combined with duct insulation or 
activated carbon injection operated at less than 400 deg.F. (62 FR at 
24232.) These beyond-the-floor considerations are identical to those 
discussed above for existing sources.
    The beyond-the-floor standard identified for existing sources 
continues to be appropriate for new sources for the same reasons. Thus, 
the promulgated dioxin/furan standard for new lightweight aggregate 
kilns is the same as the standard for existing standards, i.e., 0.20 ng 
TEQ/dscm or 0.40 ng TEQ/dscm and rapid quench of the kiln exhaust gas 
to less than 400 deg.F.
3. What Are the Mercury Standards?
    In the final rule, we establish a standard for existing and new 
lightweight aggregate kilns that limits mercury emissions to 47 and 33 
g/dscm, respectively. The rationale for adopting these 
standards is discussed below.
    a. What Is the MACT Floor for Existing Sources? All lightweight 
aggregate kilns use fabric filters, and one source uses a venturi 
scrubber in addition to a fabric filter. However, since mercury is 
generally in the vapor form in and downstream of the combustion 
chamber, including in the air pollution control device, fabric filters 
alone do not achieve significant mercury control. Mercury emissions 
from lightweight aggregate kilns are currently controlled under 
existing regulations through limits on the maximum feedrate of mercury 
in total feedstreams (e.g., hazardous waste, raw materials). Thus, MACT 
floor control is based on limiting the feedrate of mercury in hazardous 
waste.
    In the April 1996 proposal, we identified floor control as 
hazardous waste feedrate control not to exceed a feedrate level of 17 
g/dscm, expressed as a maximum theoretical emissions 
concentration, and proposed a floor emission level of 72 g/
dscm based on an analysis of data from all lightweight aggregate kilns 
with a hazardous waste feedrate of mercury of this level or lower. (61 
FR at 17404.) In the May 1997 NODA, we conducted a breakpoint analysis 
on ranked mercury emissions data and established the floor emission 
level equal to the test condition average of the breakpoint source. (62 
FR at 24232.) The breakpoint analysis was intended to reflect an 
engineering-based evaluation of the data whereby the few lightweight 
aggregate kilns spiking extra mercury during testing procedures did not 
drive the floor emission level to levels higher than the preponderance 
of the emission data. We reasoned that sources with emissions higher 
than the breakpoint source were not controlling the hazardous waste 
feedrate of mercury to levels representative of MACT. The May 1997 NODA 
analysis resulted in a MACT floor level of 47 g/dscm.
    One commenter states that the use of mercury stack gas measurements 
from RCRA compliance test reports is inappropriate for setting the MACT 
floor since they are based on feeding normal wastes. With the exception 
of one source, no mercury spiking was done during the RCRA compliance 
testing because lightweight aggregate kilns complied with Tier I levels 
allowable in the Boiler and Industrial Furnace rule. The commenter 
notes that the Tier I allowable levels are above, by orders of 
magnitude, the total mercury fed into lightweight aggregate kilns. 
Thus, to set the mercury MACT floor, the commenter states that we need 
to consider the potential range of mercury levels in the hazardous 
waste and raw materials, which may not represented by the RCRA 
compliance stack gas measurements.
    We recognize that stack gas tests generating mercury emissions data 
were conducted with normal unspiked waste streams containing normal 
levels of mercury in hazardous waste. However, we concluded that it is 
appropriate in this particular circumstance to use unspiked data to 
define a MACT floor. See discussion in Part Four, Section V.D.1. It 
would hardly reflect MACT to base the floor emission level on a 
feedrate of mercury greater than that which actually occurs in 
hazardous waste fuels burned in these units. Furthermore, the final 
rule standard is projected to be achievable by lightweight aggregate 
kilns for the vast majority of the wastes they are currently handling. 
The standard would allow lightweight aggregate kilns to burn wastes 
with about 0.5 ppmw mercury, without use of add-on mercury control 
techniques such as carbon injection. Data provided by a commenter 
indicates that approximately 90% of the waste streams lightweight 
aggregate kilns currently burn do not contain mercury levels at 2 ppmw. 
Further, the commenter indicates that these wastes are typically less 
than 0.02 ppmw mercury when more refined and costly analysis techniques 
are used. Thus, the standard is consistent with the current practice of 
lightweight aggregate kilns burning low-mercury waste.
    We received comments from the lightweight aggregate kiln industry 
expressing concern with the stringency of the mercury standard. These 
commenters oppose a mercury standard of 47 g/dscm, in part, 
because of the difficulty and increased cost of demonstrating 
compliance with day-to-day mercury feedrate limits. One potential 
problem pertains to raw material mercury detection limits. The 
commenter states that mercury is generally not measured in the raw 
material at detectable levels at their facilities. The commenter points 
out that if a kiln assumes mercury is present in the raw material at 
the detection limit, the resulting calculated uncontrolled mercury 
emission concentration could exceed, or be a significant percentage of, 
the mercury emission standard. This may prevent a kiln from complying 
with the mercury emission standard even though MACT control is used. 
Further, the commenter anticipates that more frequent analysis, 
additional laboratory equipment and staff, and improved testing and 
analysis procedures will be required to show compliance with a standard 
of 47 g/dscm. The commenter states that the costs of 
compliance will increase significantly at each facility to address this 
nondetect issue.
    Four provisions in the final rule offer flexibility in complying 
with the mercury standard. For example, one provision allows sources to 
petition for an alternative mercury standard that only requires 
compliance with a hazardous waste mercury feedrate limitation, provided 
that mercury not been present historically in the raw material at 
detectable levels. This approach ensures that kilns using MACT controls 
can achieve the mercury standard. The details of this provision are 
discussed in Part Five, Section

[[Page 52894]]

X.A.2. Another provision allows kilns a waiver of performance testing 
requirements when the source feeds low levels of mercury. Under this 
provision, a kiln qualifies for a waiver of the performance testing 
requirements for mercury if all mercury from all feedstreams fed to the 
combustion unit does not exceed the mercury emission standard. For 
kilns using this waiver, we allow kilns to assume mercury in the raw 
material is present at one-half the detection limit whenever the raw 
materials feedstream analysis determines that mercury is not present at 
detectable levels. The details of this provision are presented in Part 
Five, Section X.B. For a discussion of the other two methods that can 
be used to comply with the mercury emission standard, see Part Five, 
Section VII.B.6.
    For today's rule we use a revised engineering evaluation and data 
analysis method to establish the MACT floor emission level for mercury. 
The approach used to establish MACT floors for the three metal 
hazardous air pollutant groups and hydrochloric acid/chlorine gas is 
the aggregate feedrate approach. Using this approach, the resulting 
mercury floor emission level is 47 g/dscm.
    We estimate that approximately 75 percent of lightweight aggregate 
kiln sources currently are meeting the floor emission level. The 
national annualized compliance cost for lightweight aggregate kilns to 
reduce mercury emissions to comply with the floor emission level is 
$0.7 million for the entire hazardous waste burning lightweight 
aggregate kiln industry, and will reduce mercury emissions by 
approximately 0.03 Mg/yr or 47 percent from current baseline emissions.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the April 1996 NPRM, we considered a beyond-the-floor 
standard based on flue gas temperature reduction to 400 deg.F or less 
followed by activated carbon injection, but determined that a beyond-
the-floor level would not be cost-effective and therefore warranted. 
(61 FR at 17404.) In the May 1997 NODA, we considered a beyond-the-
floor standard of 15 g/dscm based on an activated carbon 
injection. However, we indicated in the NODA that a beyond-the-floor 
standard would not likely be justified given the high cost of treatment 
and the relatively small amount of mercury removed from air emissions. 
(62 FR at 24232.)
    In developing the final rule, we identified three techniques for 
control of mercury as a basis to evaluate a beyond-the-floor standard: 
(1) Activated carbon injection; (2) limiting the feed of mercury in the 
hazardous waste; and (3) limiting the feed of mercury in the raw 
materials. The results of each analysis are discussed below.
    Activated Carbon Injection. To investigate this beyond-the-floor 
control option, we applied a carbon injection capture efficiency of 80 
percent to the floor emission level of 47 g/dscm. The 
resulting beyond-the-floor emission level is 10 g/dscm.
    The national incremental annualized compliance cost for lightweight 
aggregate kilns to meet this beyond-the-floor level rather than comply 
with the floor controls would be approximately $0.6 million for the 
entire hazardous waste burning lightweight aggregate kiln industry and 
would provide an incremental reduction in mercury emissions beyond the 
MACT floor controls of 0.02 Mg/yr. Based on these costs of 
approximately $34 million per additional Mg of mercury removed and the 
small emissions reductions that would be realized, we conclude that 
this mercury beyond-the-floor option for hazardous waste burning 
lightweight aggregate kilns is not acceptably cost-effective nor 
otherwise justified. Therefore, we do not adopt this beyond-the-floor 
standard.
    Limiting the Feedrate of Mercury in Hazardous Waste. We also 
considered, but rejected, a beyond-the-floor emission level based on 
limiting the feed of mercury in the hazardous waste. This mercury 
beyond-the-floor option for lightweight aggregate kilns is not 
warranted because data submitted by commenters indicate that 
approximately 90% of the hazardous waste burned by lightweight 
aggregate kilns contains mercury at levels below method detection 
limits. We conclude from these data that there are little additional 
mercury reductions possible by reducing the feed of mercury in the 
hazardous waste. Therefore, we are not adopting a beyond-the-floor 
emission level because it will not be cost-effective due to the 
relatively small amount of mercury removed from air emissions and 
likely problems with method detection limitations.
    Limiting the Feedrate of Mercury in Raw Materials. A source can 
achieve a reduction in mercury emissions by substituting a feed 
material containing lower levels of mercury for a primary raw material 
higher mercury levels. This beyond-the-floor option appears to be less 
cost effective compared to either of the options evaluated above. 
Because lightweight aggregate kilns are sited proximate to primary raw 
material supply and transporting large quantities of an alternative 
source of raw material(s) is expected to be cost prohibitive. 
Therefore, we do not adopt this mercury beyond-the-floor standard.
    Thus, the promulgated mercury standard for existing hazardous waste 
burning lightweight aggregate kilns is the floor emission level of 47 
g/dscm.
    c. What Is the MACT Floor for New Sources? In the April 1996 
proposal, we identified floor control for new sources as hazardous 
waste feedrate control of mercury not to exceed a feedrate level of 17 
g/dscm expressed as a maximum theoretical emissions 
concentration. We proposed a floor emission level of 72 g/
dscm. (61 FR at 17408.) In May 1997 NODA, we conducted a breakpoint 
analysis on ranked mercury emissions data from sources utilizing the 
MACT floor technology and established the floor emission level as the 
test condition average of the breakpoint source. The breakpoint 
analysis was intended to reflect an engineering-based evaluation of the 
data so that the one lightweight aggregate kiln spiking extra mercury 
during testing procedures did not drive the floor emission level to 
levels higher than the preponderance of the emissions data. This 
analysis resulted in a MACT floor level of 47 g/dscm. (62 FR 
at 24233.)
    For the final rule, we identify floor control for new lightweight 
aggregate kilns as feed control of mercury in the hazardous waste, 
based on the single source with the best aggregate feedrate of mercury 
in hazardous waste. Using the aggregate feedrate approach to establish 
this floor level of control and corresponding floor emission level, we 
identify a MACT floor emission level of 33 g/dscm for new 
lightweight aggregate kilns.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
both the proposal and the NODA, we considered a beyond-the-floor 
standard for new sources based on activated carbon injection, but 
determined that it would not be cost-effective to adopt the beyond-the-
floor standard given the high cost of treatment and the relatively 
small amount of mercury removed from air emissions. (61 FR at 17408 and 
62 FR at 24233.)
    In the final rule, we identified three techniques for control of 
mercury as a basis to evaluate a beyond-the-floor standard: (1) 
Activated carbon injection; and (2) limiting the feed of mercury in the 
hazardous waste. The results of each analysis are discussed below.
    Activated Carbon Injection. As discussed above, we conclude that 
flue gas temperature reduction to 400  deg.F followed by activated 
carbon injection to remove mercury is an appropriate beyond-the-floor 
control option for improved mercury control at

[[Page 52895]]

lightweight aggregate kilns. The control of flue gas temperature is 
necessary to ensure good collection efficiency. Based on the MACT floor 
emission level of 33 g/dscm and assuming a carbon injection 
capture efficiency of 80 percent, we identified a beyond-the-floor 
emission level of 7 g/dscm. As discussed above for existing 
sources, we do not believe that a beyond-the-floor standard of 7 
g/dscm is warranted for new lightweight aggregate kilns due to 
the high cost of treatment and relatively small amount of mercury 
removed from air emissions. The incremental annualized compliance cost 
for one new lightweight aggregate kiln to meet this beyond-the-floor 
level, rather than comply with floor controls, would be approximately 
$0.46 million and would provide an incremental reduction in mercury 
emissions beyond the MACT floor controls of approximately 0.008 Mg/yr. 
Based on these costs of approximately $58 million per additional Mg of 
mercury removed, a beyond-the-floor standard of 7 g/dscm is 
not warranted due to the high cost of compliance and relatively small 
mercury emissions reductions. Notwithstanding our goal of reducing the 
loading to the environment by bioaccumulative pollutants such as 
mercury whenever possible, these costs are not justified.
    Limiting the Feedrate of Mercury in Hazardous Waste. As discussed 
above for existing sources, we conclude that a beyond-the-floor based 
on limiting the feed of mercury in the hazardous waste is not 
justified. Considering that the floor emission level for new 
lightweight aggregate kilns is approximately one third lower than the 
floor emission level for existing kilns (33 versus 47 g/dscm), 
we again conclude that a mercury beyond-the-floor standard is not 
warranted because emission reductions of mercury would be less than 
existing sources at comparable costs. Thus, the cost-effectiveness is 
higher for new kilns than for existing kilns. Further, achieving 
substantial additional mercury reductions by further controls on 
hazardous waste feedrate may be problematic because the mercury 
contribution from raw materials and coal represents an even larger 
proportion of the total mercury fed to the kiln. Therefore, we do not 
adopt a mercury beyond-the-floor standard based on limiting feed of 
mercury in hazardous waste for new sources.
    Thus, the promulgated mercury standard for new hazardous waste 
burning lightweight aggregate kilns is the floor emission level of 33 
g/dscm.
4. What Are the Particulate Matter Standards?
    We establish standards for both existing and new lightweight 
aggregate kilns that limit particulate matter emissions to 57 mg/dscm. 
The particulate matter standard is a surrogate control for the metals 
antimony, cobalt, manganese, nickel, and selenium. We refer to these 
five metals as ``nonenumerated metals'' because standards specific to 
each metal have not been established. The rationale for adopting these 
standards is discussed below.
    a. What Is the MACT Floor for Existing Sources? In the April 1996 
NPRM, we defined floor control based upon the performance of a fabric 
filter with an air-to-cloth ratio of 2.8 acfm/ft2. The MACT 
floor was 110 mg/dscm (0.049 gr/dscf). (61 FR at 17403.) In the May 
1997 NODA, we defined the technology basis as a fabric filter for a 
MACT floor, but did not characterize the design and operation 
characteristics of the particulate matter control equipment, air-to-
cloth ratio of a fabric filter, because we had limited information on 
these parameters. (62 FR at 24233.) Instead, for each particulate 
matter test condition, we evaluated the corresponding semivolatile 
metal system removal efficiency and screened out sources with 
relatively poor system removal efficiencies as a means to identify and 
eliminate from consideration those sources not using MACT floor 
control. Our reevaluation of the lightweight aggregate kiln particulate 
matter data resulted in a MACT floor of 50 mg/dscm (0.022 gr/dscf).
    Some commenters state that a floor emission level of 50 mg/dscm 
(0.022 gr/dscf) is too high and a particulate matter standard of 23 mg/
dscm (0.010 gr/dscf) is more appropriate because it is consistent with 
the level of performance achieved by incinerators using fabric filters. 
Even though we agree that well designed and properly operated fabric 
filters in use at all lightweight aggregate kilns can achieve low 
levels, we are concerned that an emission level of 23 mg/dscm would not 
be appropriate given the high inlet grain loading inherent with the 
lightweight aggregate manufacturing process, typically much higher than 
the particulate loading to incinerators.
    Commenters also express concern that the Agency identified 
separate, different MACT pools and associated MACT controls for 
particulate matter, semivolatile metals, and low volatile metals, even 
though all three are controlled, at least in part, by the particulate 
matter control device. These commenters stated that our approach is 
likely to result in three different design specifications. We agree 
with these commenters and, in the final rule, the same initial MACT 
pool is used to establish the floor levels for particulate matter, 
semivolatile metals, and low volatile metals. See discussion in Part 
Four, Section V.
    For the final rule, we conclude that the general floor methodology 
discussed in the May 1997 NODA is appropriate. MACT control for 
particulate matter is based on the performance of fabric filters. Since 
we lack data to fully characterize control equipment from all sources 
and we lack information on the relationship between the design 
parameters and the system performance, we evaluated both low and 
semivolatile metal system removal efficiencies associated with the 
source's particulate matter emissions to identify those sources not 
using MACT floor control. Our data show that all lightweight aggregate 
kilns are achieving greater than 99 percent system removal efficiency 
for both low and semivolatile metals, with some attaining 99.99 percent 
removal. Since we found no sources with system removal efficiencies 
indicative of poor performance, we conclude that all lightweight 
aggregate kilns are using MACT controls and the floor emission limit is 
identified as 57 mg/dscm (0.025 gr/dscf).
    The performance level of 57 mg/dscm is generally consistent with 
that expected from well designed and operated fabric filters, and that 
achieved by other similar types of combustion sources operating with 
high inlet grain loadings. We have particulate matter data from all 
lightweight aggregate kiln sources, and multiple test conditions, 
conducted at 3 year intervals, are available for many of the sources. 
We conclude that the number of test conditions available adequately 
covers the range of variability of well operated and designed fabric 
filters.166
---------------------------------------------------------------------------

    \166\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    We considered, but rejected, basing the particulate matter floor 
for lightweight aggregate kilns on the New Source Performance Standard. 
The New Source Performance Standard limits particulate matter emissions 
to 92 mg/dscm (0.040 gr/dscf), uncorrected for oxygen. (See 40 CFR 
60.730, Standards of Performance for Calciners and Dryers in Mineral 
Industries.) We rejected the New Source Performance Standard as the 
basis for the floor emission level

[[Page 52896]]

because our MACT analysis of data from existing sources indicates that 
a particulate matter floor level lower than the New Source Performance 
Standard is currently being achieved by existing hazardous waste 
burning lightweight aggregate kilns. Further, all available emission 
data for hazardous waste burning lightweight aggregate kilns are well 
below the New Source Performance Standard particulate matter standard. 
Thus, the particulate matter floor emission level is 57 mg/dscm based 
on an analysis of existing emissions data.
    We estimate that, based on a design level of 70 percent of the 
standard, over 90 percent of lightweight aggregate kiln sources 
currently are meeting the floor level. The national annualized 
compliance cost for lightweight aggregate kilns to reduce particulate 
matter emissions to comply with the floor emission level is $18,000 for 
the entire hazardous waste burning lightweight aggregate kiln industry, 
and our floor will reduce nonenumerated metals and particulate matter 
emissions by 0.01 Mg/yr and 2.7 Mg/yr, respectively, or 7 percent from 
current baseline emissions.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the NPRM, we proposed a beyond-the-floor emission level of 
69 mg/dscm (0.030 gr/dscf) and solicited comment on an alternative 
beyond-the-floor emission level of 34 mg/dscm (0.015 gr/dscf) based on 
improved particulate matter control. (61 FR at 17403.) In the May 1997 
NODA, we concluded that a beyond-the-floor standard may not be 
warranted given a reduced particulate matter floor level compared to 
the proposed floor emission level. (62 FR at 24233.)
    In the final rule, we considered a beyond-the-floor level of 34 mg/
dscm for existing lightweight aggregate kilns based on improved 
particulate matter control. For analysis purposes, improved particulate 
matter control entails the use of higher quality fabric filter bag 
material. We then determined the cost of achieving this level of 
particulate matter, with corresponding reductions in the nonenumerated 
metals for which particulate matter is a surrogate, to determine if 
this beyond-the-floor level would be appropriate. The national 
incremental annualized compliance cost for lightweight aggregate kilns 
to meet this beyond-the-floor level, rather than comply with the floor 
controls, would be approximately $110,000 for the entire hazardous 
waste burning lightweight aggregate kiln industry and would provide an 
incremental reduction in nonenumerated metals emissions nationally 
beyond the MACT floor controls of 0.03 Mg/yr. Based on these costs of 
approximately $3.7 million per additional Mg of nonenumerated metals 
emissions removed, we conclude that this beyond-the-floor option for 
lightweight aggregate kilns is not acceptably cost-effective nor 
otherwise justified. Therefore, we do not adopt this beyond-the-floor 
standard. Thus, the promulgated particulate matter standard for 
existing hazardous waste burning lightweight aggregate kilns is the 
floor emission level of 57 mg/dscm.
    c. What Is the MACT Floor for New Sources? In the April 1996 
proposal, we defined floor control for new sources based on the level 
of performance of a fabric filter with an air-to-cloth ratio of 1.5 
acfm/ft2. The MACT floor emission level was 120 mg/dscm (0.054 gr/
dscf). (61 FR at 17408.) In the May 1997 NODA, MACT control was defined 
as a well-designed and properly operated fabric filter, and the floor 
emission level for new lightweight aggregate kilns was 50 mg/dscm 
(0.022 gr/dscf). (62 FR at 24233.)
    All lightweight aggregate kilns use fabric filters to control 
particulate matter. As discussed earlier, we have limited information 
on the design and operation characteristics of existing control 
equipment currently used by lightweight aggregate kilns. As a result, 
we are unable to identify a specific technology that can consistently 
achieve lower emission levels than the controls used by lightweight 
aggregate kilns achieving the MACT floor level for existing sources. 
Lightweight aggregate kilns achieve the floor emission level with well-
designed and properly operated fabric filters. Thus, floor control for 
new kilns is likewise a well-designed and properly operated fabric 
filter. Therefore, as discussed for existing sources, the MACT floor 
level for new lightweight aggregate kilns is 57 mg/dscm (0.025 gr/
dscf).
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the April 1996 NPRM, we proposed a beyond-the-floor standard of 69 mg/
dscm (0.030 gr/dscf) based on improved particulate matter control, 
which was consistent with existing sources. (61 FR at 17408.) In the 
May 1997 NODA, we concluded, as we did for existing sources, that a 
beyond-the-floor level for particulate matter may not be warranted due 
to the high costs of control and relatively small amount of particulate 
matter removed from air emissions. (62 FR at 24233.)
    As discussed for existing sources, we considered a beyond-the-floor 
level of 34 mg/dscm for new lightweight aggregate kilns based on 
improved particulate matter control. For analysis purposes, improved 
particulate matter control entails the use of higher quality fabric 
filter bag material. We then determined the cost of achieving this 
level of particulate matter, with corresponding reductions in the 
nonenumerated metals for which particulate matter is a surrogate, to 
determine if this beyond-the-floor level would be appropriate. The 
incremental annualized compliance cost for one new lightweight 
aggregate kiln to meet this beyond-the-floor level, rather than comply 
with floor controls, would be approximately $38 thousand and would 
provide an incremental reduction in nonenumerated metals emissions of 
approximately 0.012 Mg/yr.167 Based on these costs of 
approximately $3.1 million per additional Mg of nonenumerated metals 
removed, we conclude that a beyond-the-floor standard of 34 mg/dscm is 
not justified due to the high cost of compliance and relatively small 
nonenumerated metals emission reductions. Further, a standard of 57 mg/
dscm would adequately control the unregulated hazardous air pollutant 
metals for which it is being used as a surrogate. Thus, the particulate 
matter standard for new lightweight aggregate kilns is the floor level 
of 57 mg/dscm.
---------------------------------------------------------------------------

    \167\ Based on the data available, the average emissions in sum 
of the five nonenumerated metal from lightweight aggregate kilns 
using MACT particulate matter control is approximately 83 
g/dscm. To estimate emission reductions of the 
nonenumerated metals, we assume a linear relationship between a 
reduction in particulate matter and these metals.
---------------------------------------------------------------------------

5. What Are the Semivolatile Metals Standards?
    In the final rule, we establish a standard for existing and new 
lightweight aggregate kilns that limits semivolatile metal emissions to 
250 and 43 g/dscm, respectively. The rationale for adopting 
these standards is discussed below.
    a. What Is the MACT Floor for Existing Sources? All lightweight 
aggregate kilns use a combination of particulate matter control, i.e., 
a fabric filter, and hazardous waste feedrate to control emissions of 
semivolatile metals. Current RCRA regulations establish limits on the 
maximum feedrate of lead and cadmium in all feedstreams. Thus, 
hazardous waste feedrate control is part of MACT floor control.
    In the April 1996 proposal, we defined floor control as either (1) 
a fabric filter with an air-to-cloth ratio of 1.5 acfm/ft 2 
and a hazardous waste feedrate level of 270,000 g/dscm,

[[Page 52897]]

expressed as a maximum theoretical emissions concentration; or (2) a 
combination of a fabric filter and venturi scrubber with an air-to-
cloth ratio of 4.2 acfm/ft 2 and a hazardous waste feedrate 
level of 54,000 g/dscm. The proposed floor emission level was 
12 g/dscm. (61 FR at 17405.) In the May 1997 NODA, we 
discussed a floor methodology where we used a breakpoint analysis to 
identify sources that were not using floor control with respect either 
to semivolatile metals hazardous waste feedrate or emissions control. 
Under this approach, we ranked semivolatile metal emissions data from 
sources that were achieving the particulate matter floor level of 50 
mg/dscm or better. We identified the floor level as the test condition 
average associated with the breakpoint source. Thus, sources with 
atypically high emissions because of high semivolatile feedrate levels 
or poor semivolatile metals control were screened from the pool of 
sources used to define the floor emission level. Based on this 
analysis, we identified a floor emission level of 76 g/dscm. 
(62 FR at 24234.)
    We received few public comments in response to the proposal and May 
1997 NODA concerning the lightweight aggregate kiln semivolatile metals 
floor emission level. We did receive comments on the application of 
techniques to identify breakpoints in the arrayed emissions data. This 
issue and our response to it are discussed in the floor methodology 
section in Part Four, Section V. We also received comments that our 
semivolatile metals analysis in the proposal and May 1997 NODA included 
several data base inaccuracies that, when corrected, would result in a 
higher floor level. We agree with the commenters and we revised the 
data base as necessary for the final rule analysis.
    In the final rule, in general response to these comments, we use a 
revised engineering evaluation and data analysis method to establish 
the floor emission level for semivolatile metals. We use the aggregate 
feedrate approach in conjunction with floor control for particulate 
matter of 57 mg/dscm to identify a semivolatile metal floor emission 
level of 1,700 g/dscm. We estimate that all lightweight 
aggregate kiln sources currently are meeting the floor level.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the April 1996 NPRM, we considered a beyond-the-floor 
emission level for semivolatile metals based on improved particulate 
matter control. We concluded that a beyond-the-floor emission level 
would not be cost-effective given that the proposed semivolatile metal 
floor level of 12 g/dscm alone would result in an estimated 97 
percent reduction in semivolatile metal emissions. (61 FR at 17405.) In 
the May 1997 NODA, we considered a beyond-the-floor emission level 
based on improved particulate matter control, but indicated that such a 
standard was not likely to be cost-effective due to the high costs of 
control. (62 FR at 24234.)
    In developing the final rule, we identified three techniques for 
control of semivolatile metals as a basis to evaluate a beyond-the-
floor standard: (1) Limiting the feed of semivolatile metals in the 
hazardous waste; (2) improved particulate matter control; and (3) 
limiting the feed of semivolatile metals in the raw materials. The 
results of each analysis are discussed below.
    Limiting the Feedrate of Semivolatile Metals in Hazardous Waste. 
Under this option, as with cement kilns, we selected for evaluation a 
beyond-the-floor emission level of 240 g/dscm to evaluate from 
among the range of possible levels that reflect improved feedrate 
control of semivolatile metals in hazardous waste. This emission level 
represents a significant increment of emission reduction from the floor 
level of 1700 g/dscm, it is within the range of levels that 
are likely to be reasonably achievable using feedrate control, and it 
is generally consistent with the incinerator and cement kiln standards, 
thereby advancing a policy objective of essentially common standards 
among combustors of hazardous waste.
    In performing an analysis of the 240 g/dscm beyond-the-
floor limit, we found that additional reductions beyond 250 g/
dscm represent a significant reduction in cost-effectiveness of 
incremental beyond-the-floor levels. A beyond-the-floor standard of 250 
g/dscm achieves the same goals as a beyond-the-floor standard 
of 240 g/dscm in a more cost-effective manner. The national 
incremental annualized compliance cost for the lightweight aggregate 
kilns to meet this 250 g/dscm beyond-the-floor level, rather 
than comply with the floor controls, would be approximately $88,000 and 
would provide an incremental reduction beyond emissions at the MACT 
floor in semivolatile metal emissions of an additional 0.17 Mg/yr. The 
cost-effectiveness of this emission level is approximately $530,000 per 
additional Mg of semivolatile metal removed.
    We conclude that additional control of the feedrate of semivolatile 
metals in hazardous waste to achieve an emission level of 250 
g/dscm is warranted because this standard would reduce lead 
and cadmium emissions, which are particularly toxic hazardous air 
pollutants. In addition, Solite Corporation, which operates the 
majority of the hazardous waste burning lightweight aggregate kilns, 
stated in their public comments that a standard of 213 g/dscm 
is achievable and adequately reflects the variability of lead and 
cadmium in raw material for their kilns. Further, the vast majority of 
the lead and cadmium fed to the lightweight aggregate kiln is from the 
hazardous waste,168 not from the raw material or coal. We 
are willing to accept a more marginal cost-effectiveness for sources 
voluntarily burning hazardous waste in lieu of other fuels to ensure 
that sources are using best controls.
---------------------------------------------------------------------------

    \168\ USEPA, ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies'', July 1999.
---------------------------------------------------------------------------

    Moreover, this beyond-the-floor semivolatile metal standard better 
supports our Children's Health Initiative in that lead emissions, which 
are of highest significance to children's health, will be reduced by 
another 60 percent from today's baseline. We are committed to reducing 
lead emissions wherever and whenever possible. Finally, we note that 
this beyond-the-floor standard is also consistent with European Union 
standards for hazardous waste incinerators of approximately 200 
g/dscm for lead and cadmium combined. Therefore, we are 
adopting today a beyond-the-floor standard of 250 g/dscm for 
existing lightweight aggregate kilns.
    Improved Particulate Matter Control. We also evaluated improved 
particulate matter control as another beyond-the-floor control option 
for improved semivolatile metals control. We investigated a beyond-the-
floor standard of 250 g/dscm, an emission level consistent 
with the preferred option based on limiting the feedrate of 
semivolatile metals in hazardous waste. The national incremental 
annualized compliance cost for lightweight aggregate kilns to meet this 
beyond-the-floor level, rather than comply with the floor controls, 
would be approximately $88,000 thousand for all lightweight aggregate 
kilns and would provide an incremental reduction in semivolatile metal 
emissions beyond the MACT floor controls of 0.17 Mg/yr. Based on these 
costs of approximately $530,000 per additional Mg of semivolatile metal 
removed, we determined that this beyond-the-floor option may be 
warranted. However, as discussed below, the cost-effectiveness for this 
beyond-the-floor option is approximately equivalent to the costs

[[Page 52898]]

estimated for a beyond-the-floor option based on limiting the feed of 
semivolatile metals in the hazardous waste. We decided to base the 
beyond-the-floor standard for semivolatile metals on the feedrate 
option to be consistent with the cement kiln approach. Of course light-
weight aggregate kilns are free to choose to improve particulate matter 
control in lieu of feedrate controls as their vehicle to achieve 
compliance with 250 ug/dscm.
    Limiting the Feedrate of Semivolatile Metals in Raw Materials. A 
source can achieve a reduction in semivolatile metals emissions by 
substituting a feed material containing lower levels of lead and/or 
cadmium for a primary raw material higher in lead and/or cadmium 
levels. This beyond-the-floor option appears to be less cost effective 
compared to either of the options evaluated above because lightweight 
aggregate kilns are sited proximate to primary raw material supply. 
Transporting large quantities of an alternative source of raw 
material(s) is expected to be cost prohibitive. Therefore, we do not 
adopt this semivolatile metal beyond-the-floor standard.
    Thus, the promulgated semivolatile metals standard for existing 
hazardous waste burning lightweight aggregate kilns is a beyond-the-
floor standard of 250 g/dscm based on limiting the feedrate of 
semivolatile metals in the hazardous waste.
    c. What Is the MACT Floor for New Sources? In the April 1996 
proposal, we defined floor control as a fabric filter with an air-to-
cloth ratio of 1.5 acfm/ft2 and a hazardous waste feedrate 
level of 270,000 g/dscm, expressed as a maximum theoretical 
emissions concentration. The proposed floor emission level was 5.2 
g/dscm. (61 FR at 17408.) In the May 1997 NODA, we concluded 
that the floor control and emission level for existing sources for 
semivolatile metals would also be appropriate for new sources. Floor 
control was based on a combination of good particulate matter control 
and limiting hazardous waste feedrates of semivolatile metals to 
control emissions. We used a breakpoint analysis of the semivolatile 
metal emissions data to exclude sources achieving substantially poorer 
semivolatile metal control than the majority of sources. The NODA floor 
emission level was 76 g/dscm for new sources. (62 FR at 
24234.)
    In the final rule, as discussed previously, we use a revised 
engineering evaluation and data analysis method to establish the floor 
emission level for semivolatile metals. We use the aggregate feedrate 
approach in conjunction with floor control for particulate matter of 57 
mg/dscm to identify a semivolatile metal floor emission level of 43 
g/dscm.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the April 1996 NPRM and May 1997 NODA, we considered a semivolatile 
metal beyond-the-floor emission level for new sources, but determined 
that the standard would not be cost-effective because the floor 
emission levels already achieved significant reductions in semivolatile 
metals emissions. (61 FR at 17408 and 62 FR at 24234.)
    For the final rule, we do not adopt a beyond-the-floor emission 
level because the MACT floor for new sources is already substantially 
lower than the beyond-the-floor emission standard for existing sources. 
As a result, a beyond-the-floor standard for new lightweight aggregate 
kilns is not warranted due to the high costs of control versus the 
minimal emissions reductions that would be achieved. Therefore, we 
adopt the semivolatile metal MACT floor standard of 43 g/dscm 
for new hazardous waste burning lightweight aggregate kilns.
6. What Are the Low Volatile Metals Standards?
    In the final rule, we establish a standard for both existing and 
new lightweight aggregate kilns that limits low volatile metal 
emissions to 110 g/dscm. The rationale for adopting these 
standards is discussed below.
    a. What Is the MACT Floor for Existing Sources? In the April 1996 
proposal, we defined floor control based on the performance of a fabric 
filter with an air-to-cloth ratio of 1.8 acfm/ft2 and a 
hazardous waste feedrate level of 46,000 g/dscm, expressed as 
a maximum theoretical emissions concentration. The proposed floor 
emission level was 340 g/dscm. (61 FR at 17405.) In the May 
1997 NODA, we discussed a floor methodology where we used a breakpoint 
analysis to identify sources that were not using floor control with 
respect either to low volatile metals hazardous waste feedrate or 
emissions control. Under this approach, we ranked low volatile metal 
emissions data from sources that were achieving the particulate matter 
floor level of 50 mg/dscm or better. We identified the floor level as 
the test condition average associated with the breakpoint source. Thus, 
sources with atypically high emissions because of high low volatile 
feedrate levels or poor low volatile metals control were screened from 
the pool of sources used to define the floor emission level. Based on 
this analysis, we identified a floor emission level of 37 g/
dscm. (62 FR at 24234.)
    We received few comments, in response to the April 1996 NPRM and 
May 1997 NODA, concerning the low volatile metals floor emission level. 
We received comments, however, on several overarching issues including 
the appropriateness of considering feedrate control of metals 
(including low volatile metals) in hazardous waste as a MACT floor 
control technique and the specific procedure of identifying breakpoints 
of arrayed emissions data. These issues and our responses to them are 
discussed in the floor methodology section in Part Four, Section V.
    For today's rule, we use a revised engineering evaluation and data 
analysis method to establish the MACT floor level for low volatile 
metals. The aggregate feedrate approach in conjunction with MACT 
particulate matter control to 57 mg/dscm results in a low volatile 
metal floor emission level of 110 g/dscm.
    We estimate that over 80 percent of existing lightweight aggregate 
kiln sources in our data base meet the floor level. The national 
annualized compliance cost for lightweight aggregate kilns to reduce 
low volatile metal emissions to comply with the floor emission level is 
$52,000 for the entire hazardous waste burning lightweight aggregate 
kiln industry, and will reduce low volatile metal emissions by 0.04 Mg/
yr or 40 percent from current baseline emissions.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the April 1996 NPRM and May 1997 NODA, we considered a 
beyond-the-floor standard for low volatile metals based on improved 
particulate matter control. However, we concluded that a beyond-the-
floor standard would not be cost-effective due to the high cost of 
emissions control and relatively small amount of low volatile metals 
removed from air emissions. (61 FR at 17406 and 62 FR at 24235.)
    For today's rule, we identified three potential beyond-the-floor 
techniques for control of low volatile metals: (1) Improved particulate 
matter control; (2) limiting the feed of low volatile metals in the 
hazardous waste; and (3) limiting the feed of low volatile metals in 
the raw materials. The results of each analysis are discussed below.
    Improved Particulate Matter Control. Our judgment is that a beyond-
the-floor standard based on improved particulate matter control would 
be less cost-effective that a beyond-the-floor option based on limiting 
the feedrate of low

[[Page 52899]]

volatile metals in the hazardous waste. Our data show that lightweight 
aggregate kilns are already achieving a 99.9% system removal efficiency 
of low volatile metals and some sources are even attaining 99.99%. 
Thus, pollution control equipment retrofit costs for improved control 
would be significant. Thus, we conclude a beyond-the-floor emission 
level for low volatile metals based on improved particulate matter 
control for lightweight aggregate kilns is not warranted.
    Limiting the Feedrate of Low Volatile Metals in the Hazardous 
Waste. We also considered a beyond-the-floor level of 70 g/
dscm based on additional feedrate control of low volatile metals in the 
hazardous waste. Our investigation shows that this beyond-the-floor 
option would achieve an incremental reduction in low volatile metals of 
only 0.01 Mg/yr. Given that this beyond-the-floor level would not 
achieve appreciable emissions reductions, significant cost-
effectiveness considerations would likely arise, thus suggesting that 
this beyond-the-floor standard is not warranted.
    Limiting the Feedrate of Low Volatile Metals in Raw Materials. A 
source can achieve a reduction in low volatile metal emissions by 
substituting a feed material containing lower levels of these metals 
for a primary raw material higher low volatile metal levels. This 
beyond-the-floor option appears to be less cost-effective compared to 
either of the options evaluated above because lightweight aggregate 
kilns are sited proximate to primary raw material supply. Transporting 
large quantities of an alternative source of raw material(s) is 
expected to be very costly and not cost-effective considering the 
limited emissions reductions that would be achieved. Therefore, we do 
not adopt this low volatile metals beyond-the-floor standard.
    For reasons discussed above, we do not adopt a beyond-the-floor 
level for low volatile metals, and establish the emissions standard for 
existing hazardous waste burning lightweight aggregate kilns at 110 
g/dscm.
    c. What Is the MACT Floor for New Sources? At proposal, we defined 
floor control based on the performance of a fabric filter with an air-
to-cloth ratio of 1.3 acfm/ft2 a hazardous waste feedrate 
level of 37,000 g/dscm, expressed as a maximum theoretical 
emissions concentration. The proposed floor level was 55 g/
dscm. (61 FR at 17408.) In the May 1997 NODA, we concluded that the 
floor control and emission level for existing sources for low volatile 
metals would also be appropriate for new sources. Floor control was 
based on a combination of good particulate matter control and limiting 
hazardous waste feedrate of low volatile metals to control emissions. 
We used a breakpoint analysis of the low volatile metal emissions data 
to exclude sources achieving substantially poorer low volatile metal 
control than the majority of sources. The NODA floor was 37 g/
dscm. (62 FR at 24235.)
    In the final rule, in response to general comments on the May 1997 
NODA, we use a revised engineering evaluation and data analysis method 
to establish the floor emission level for low volatile metals. We use 
the aggregate feedrate approach in conjunction with floor control for 
particulate matter of 57 mg/dscm to identify a low volatile metal floor 
emission level of 110 g/dscm.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the April 1996 NPRM and May 1997 NODA, we considered a low volatile 
metal beyond-the-floor level, but determined that a beyond-the-floor 
standard would not be cost-effective due to the high cost of treatment 
and relatively small amount of low volatile metals removed from air 
emissions. We received no comments to the contrary.
    For the final rule, as discussed for existing sources, we do not 
adopt a beyond-the-floor level for new sources, and conclude that the 
floor emission level is appropriate. Therefore, we adopt the low 
volatile metal floor level of 110 g/dscm as the emission 
standard for new hazardous waste burning lightweight aggregate kilns.
7. What Are the Hydrochloric Acid and Chlorine Gas Standards?
    In the final rule, we establish a standard for existing and new 
lightweight aggregate kilns that limits hydrochloric acid and chlorine 
gas emissions to 230 and 41 ppmv, respectively. The rationale for 
adopting these standards is discussed below.
    a. What Is the MACT Floor for Existing Sources? In the April 1996 
proposal, we identified floor control for hydrochloric acid/chlorine 
gas as either: (1) Hazardous waste feedrate control of chlorine to 1.5 
g/dscm, expressed as a maximum theoretical emissions concentration; or 
(2) a combination of a venturi scrubber and hazardous waste feedrate 
level of 14 g/dscm, expressed as a maximum theoretical emissions 
concentration. The proposed floor emission level was 2100 ppmv. (61 FR 
at 17406.) In the May 1997 NODA, we used the same data analysis method 
as proposed, except that a computed emissions variability factor was no 
longer added. The floor emission level was 1300 ppmv. (62 FR at 24235.)
    We received few comments concerning the hydrochloric acid/chlorine 
gas floor methodology and emission level. One commenter supports the 
use of a variability factor in calculating the floor emission level. 
Generally, the final emission standards, including hydrochloric acid/
chlorine gas, already accounts for emissions variability without adding 
a statistically-derived emissions variability factor. This issue and 
our response to it are discussed in detail in the floor methodology 
section in Part Four, Section V.
    For today's rule, we use a revised engineering evaluation and data 
analysis method to establish the MACT floor level for hydrochloric acid 
and chlorine gas. The aggregate feedrate approach results in a floor 
emission level of 1500 ppmv.
    We estimate that approximately 31 percent of lightweight aggregate 
kilns in our data base currently meet the floor emission level. The 
national annualized compliance cost for sources to reduce hydrochloric 
acid and chlorine gas emissions to comply with the floor level is 
$350,000 for the entire hazardous waste burning lightweight aggregate 
kiln industry, and will reduce hydrochloric acid and chlorine gas 
emissions by 182 Mg/yr or 10 percent from current baseline emissions.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the April 1996 proposal, we defined beyond-the-floor 
control as wet or dry lime scrubbing with a control efficiency of 90 
percent. We proposed a beyond-the-floor standard of 450 ppmv, which 
included a statistical variability factor. (61 FR at 17406.) In the May 
1997 NODA, the beyond-the-floor standard was 130 ppmv based on wet or 
dry scrubbing with a control efficiency of 90 percent. (62 FR at 
24235.)
    We identified three potential beyond-the-floor techniques for 
control of hydrochloric acid and chlorine gas emissions: (1) Dry lime 
scrubbing; (2) limiting the feed of chlorine in the hazardous waste; 
and (3) limiting the feed of chlorine in the raw materials. The result 
of each analysis is discussed below.
    Dry Lime Scrubbing. Based on a joint emissions testing program with 
Solite Corporation in 1997, dry lime scrubbing at a stoichiometric lime 
ratio of 3:1 achieved greater than 85 percent removal of hydrochloric 
acid and chlorine gas. For the final rule, we considered a beyond-the-
floor emission level of 230 ppmv based on a 85 percent removal 
efficiency from the floor level of 1500 ppmv.

[[Page 52900]]

    The national incremental annualized compliance cost for all 
lightweight aggregate kilns to meet this beyond-the-floor level is 
approximately $1.5 million. This would provide an incremental reduction 
in hydrochloric acid/chlorine gas emissions beyond the MACT floor 
controls of an additional 1320 Mg/yr, or 80 percent. Based on these 
costs of approximately $1,100 per additional Mg hydrochloric acid/
chlorine gas removed, this hydrochloric acid/chlorine gas beyond-the-
floor option for lightweight aggregate kilns is justified. Therefore, 
we are adopting a beyond-the-floor standard of 230 ppmv for existing 
lightweight aggregate kilns.
    One commenter disagreed with our proposal to base the beyond-the-
floor standard on dry lime scrubbing achieving 90% removal. The 
commenter states that dry lime scrubbing cannot cost-effectively 
achieve 90 percent control of hydrochloric acid and chlorine gas 
emissions. To achieve a 90 percent capture efficiency at a 
stoichiometric ratio of 3:1, the commenter maintains that a source 
would need to install special equipment and make operational 
modifications that are less cost-effective than simple dry lime 
scrubbing at a lower removal efficiency. The commenter identifies this 
lower level of control at 80 percent based on the joint emissions 
testing program.169 The commenter does agree, however, that 
dry lime scrubbing can achieve 90 percent capture without the 
installation of special equipment by operating at a stoichiometric lime 
ratio greater than 3:1. One significant consequence of operating at 
higher stoichiometric lime ratios, the commenter states, is the adverse 
impact to the collected particulate matter. Currently, the collected 
particulate matter is recycled into the lightweight aggregate product. 
At higher stoichiometric lime ratios, unreacted lime and collected 
chloride and sulfur salts would prevent this recycling practice and 
would require the disposal of all the collected particulate matter at 
significant and unjustified costs.
---------------------------------------------------------------------------

    \169\ See ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    We agree with the commenter that data from the joint emissions 
testing program does not support a 90 percent capture efficiency by 
simple dry lime scrubbing at a stoichiometric lime ratio of 3:1. We 
disagree with the commenter that the data support an efficiency no 
greater than 80 percent. In the testing program, we evaluated the 
capture efficiency of lime during four runs at a stoichiometric lime 
ratio of approximately 3:1. The results show that hydrochloric acid was 
removed at rates ranging from 86 to 91 percent with one exception. For 
that one run, the removal was calculated as 81 percent. For reasons 
detailed in the Comment Response Document and in the technical support 
document,170 we conclude that the data from this run should 
not be considered because the calculated stoichiometric lime ratio is 
suspect. When we remove this data point from consideration, the 
available information clearly indicates that dry lime scrubbing at a 
stoichiometric ratio of 3:1 can achieve greater than 85 percent 
removal. Therefore, in the final rule, we base the beyond-the-floor 
standard of 230 ppmv on 85 percent removal.
---------------------------------------------------------------------------

    \170\ See ``Final Technical Support Document for HWC MACT 
Standards, Volume III: Selection of MACT Standards and 
Technologies,'' July 1999.
---------------------------------------------------------------------------

    Limiting the Feedrate of Chlorine in the Hazardous Waste. We also 
considered a beyond-the-floor standard for hydrochloric acid/chlorine 
gas based on additional feedrate control of chlorine in the hazardous 
waste. This option achieves lower emission reductions and is less cost-
effective than the dry lime scrubbing option discussed above. 
Therefore, we are not adopting a hydrochloric acid/chlorine gas beyond-
the-floor standard based on limiting the feed of chlorine in the 
hazardous waste.
    Limiting the Feedrate of Chlorine in the Raw Materials. A source 
can achieve a reduction in hydrochloric acid/chlorine gas emissions by 
substituting a feed material containing lower levels of chlorine for a 
primary raw material higher chlorine levels. This beyond-the-floor 
option appears to be less cost effective compared to either of the 
options evaluated above because lightweight aggregate kilns are sited 
proximate to primary raw material supply. Transporting large quantities 
of an alternative source of raw material(s) is expected to be very 
costly and not cost-effective considering the limited emissions 
reductions that would be achieved. Therefore, we do not adopt this 
hydrochloric acid/chlorine gas beyond-the-floor standard.
    In summary, we establish the hydrochloric acid/chlorine gas 
standard for existing lightweight aggregate kilns at 230 ppmv based on 
scrubbing.
    c. What Is the MACT Floor for New Sources? In the April 1996 
proposal, we defined MACT floor control for new sources as a venturi 
scrubber with a hazardous waste feedrate level of 14 g/dscm, expressed 
as a maximum theoretical emissions concentration. We proposed a floor 
emission level of 62 ppmv. (61 FR at 17409.) In the May 1997 NODA, we 
concluded that the floor control and emission level for existing 
sources for hydrochloric acid/chlorine gas would also be appropriate 
for new sources. Floor control was based on limiting hazardous waste 
feedrates of chlorine to control hydrochloric acid/chlorine gas 
emissions. We screened out some data with anomalous system removal 
efficiencies compared to the majority of sources. The floor emission 
level for new lightweight aggregate kilns was 43 ppmv. (62 FR at 
24235.)
    In the final rule, we use a similar engineering evaluation and data 
analysis method as discussed in the May 1997 NODA to establish the 
floor emission level for hydrochloric acid/chlorine gas. We identified 
MACT floor control as wet scrubbing since the best controlled source is 
using this control technology. One lightweight aggregate facility uses 
venturi-type wet scrubbers for the control of hydrochloric acid/
chlorine gas. We evaluated the chlorine system removal efficiencies 
achieved by wet scrubbing at this facility. Our data show that this 
facility is consistently achieving greater than 99 percent control of 
hydrochloric acid/chlorine gas. Because we have no data with system 
removal efficiencies indicative of poor performance, we conclude that 
all data from this facility are reflective of MACT control (wet 
scrubbers), and, therefore, the floor emission limit for new sources is 
set equal to the highest test condition average of these data. Thus, 
the MACT floor emission limit for new lightweight aggregate kilns is 
identified as 41 ppmv.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the April 1996 proposal and May 1997 NODA, we did not propose a beyond-
the-floor standard for new sources because the floor emission level was 
based on wet scrubbing, which is the best available control technology 
for hydrochloric acid/chlorine gas. (61 FR at 17409 and 62 FR at 
24235.) We continue to believe that a beyond-the-floor emission level 
for new sources is not warranted due to the high costs of treatment and 
the small additional amount of chlorine that would be removed. 
Therefore, the MACT standard for new lightweight aggregate kilns is 
identified as 41 ppmv.
8. What Are the Hydrocarbon and Carbon Monoxide Standards?
    In the final rule, we establish hydrocarbon and carbon monoxide 
standards as surrogates to control emissions of nondioxin organic 
hazardous air pollutants for existing and

[[Page 52901]]

new lightweight aggregate kilns. The standards limit hydrocarbon and 
carbon monoxide concentrations to 20 ppmv 171 or 100 ppmv, 
172 respectively. Existing and new lightweight aggregate 
kilns can elect to comply with either the hydrocarbon limit or the 
carbon monoxide limit on a continuous basis. Lightweight aggregate 
kilns that choose to comply with the carbon monoxide limit on a 
continuous basis must also demonstrate compliance with the hydrocarbon 
standard during the comprehensive performance test. However, continuous 
hydrocarbon monitoring following the performance test is not 
required.173 We discuss the rationale for establishing these 
standards below.
---------------------------------------------------------------------------

    \171\ Hourly rolling average, reported as propane, dry basis and 
corrected to 7 percent oxygen.
    \172\Hourly rolling average, dry basis, corrected to 7 percent 
oxygen.
    \173\As discussed in Part 5, Section X.F, lightweight aggregate 
kilns that feed hazardous waste at a location other than the end 
where products are normally discharged and where fuels are normally 
fired must comply with the 20 ppmv hydrocarbon standards (i.e., 
these sources do not have the option to comply with the carbon 
monoxide standard).
---------------------------------------------------------------------------

    a. What Is the MACT Floor for Existing Sources? As discussed in 
Part Four, Section II.A.2, we proposed limits on hydrocarbon and carbon 
monoxide emissions as surrogates to control nondioxin organic hazardous 
air pollutants. In the April 1996 NPRM, we identified floor control as 
combustion of hazardous waste under good combustion practices to 
minimize the generation of fuel-related hydrocarbons. We proposed a 
hydrocarbon emission level of 14 ppmv and a carbon monoxide level of 
100 ppmv. The hydrocarbon level was based on an analysis of the 
available emissions data, while the basis of the carbon monoxide level 
was existing federal regulations (see Sec. 266.104(b)). (61 FR at 
17407.) In the May 1997 NODA, we solicited comment a hydrocarbon 
emission level of 10 ppmv. The hydrocarbon floor level was changed to 
10 ppmv from 14 ppmv because of a change in the lightweight aggregate 
kiln universe of facilities. The lightweight aggregate kiln with the 
highest hydrocarbon emissions stopped burning hazardous waste. With the 
exclusion of the hydrocarbon data from this one source, the remaining 
lightweight aggregate kilns appeared to be able to meet a hydrocarbon 
standard on the order of 6 ppmv. However, since we were unable to 
identify an engineering reason why lightweight aggregate kilns using 
good combustion practices should be able to achieve lower hydrocarbon 
emissions than incinerators, we indicated that it may be more 
appropriate to establish the hydrocarbon standard at 10 ppmv, which was 
equal to the incinerator emission level discussed in that NODA. In the 
NODA, we also continued to indicate our preference for a carbon 
monoxide emission level of 100 ppmv. (62 FR at 24235.)
    One commenter states that some lightweight aggregate kilns may not 
be able to meet a 10 ppmv hydrocarbon standard due to organics in raw 
materials. Notwithstanding our data base of short-term data indicating 
the achievability of a hydrocarbon standard of 10 ppmv, the commenter 
states that this standard may be unachievable over the long-term 
because trace levels of organic matter in the raw materials vary 
significantly. Hydrocarbon emissions could increase as the source uses 
raw materials from different on-site quarry locations. Thus, the 
commenter supports a hydrocarbon emission level consistent with cement 
kilns (i.e., 20 ppmv), and opposes a floor emission level that is 
comparable to incinerators for which low temperature organics 
desorption from raw materials is not a complicating issue.
    Our limited hydrocarbon data, as discussed above, indicates that a 
hydrocarbon level of 10 ppmv is achievable for lightweight aggregate 
kilns.174 However, we agree that over long-term operations, 
lightweight aggregate kilns may encounter variations in the level of 
trace organics in raw materials, similar to cement kilns, that may 
preclude some kilns from achieving a hydrocarbon limit of 10 ppmv. 
Thus, we conclude that a hydrocarbon emission level of 20 ppmv, the 
same floor level for cement kilns, is also appropriate for lightweight 
aggregate kilns. A hydrocarbon standard of 20 ppmv also is based on 
existing federally-enforceable RCRA regulations, to which lightweight 
aggregate kilns are currently subject. (See Sec. 266.104(c).)
---------------------------------------------------------------------------

    \174\ Our data base for hydrocarbons consists of short-term 
emissions data.
---------------------------------------------------------------------------

    Some commenters also support a requirement for both a carbon 
monoxide and hydrocarbon limit for lightweight aggregate kilns. These 
commenters state that requiring both hydrocarbon and carbon monoxide 
limits would further reduce emissions of organic hazardous air 
pollutants. One commenter notes that 83 percent of existing lightweight 
aggregate kilns are currently achieving both a hydrocarbon level of 20 
ppmv and a carbon monoxide standard of 100 ppmv.
    We carefully considered the merits and drawbacks to requiring both 
a hydrocarbon and carbon monoxide standard. First, stack gas carbon 
monoxide levels may not be a universally reliable indicator of 
combustion intensity and efficiency for some lightweight aggregate 
kilns due, first, to carbon monoxide generation by disassociation of 
carbon dioxide to carbon monoxide at high temperatures and, second, to 
evolution of carbon monoxide from the trace organic constituents in raw 
material feedstock.175 One commenter supports our view by 
citing normal variability in carbon monoxide levels at their kiln with 
no apparent relationship to combustion conditions, such as temperature, 
residence time, excess oxygen levels. Thus, carbon monoxide can be 
overly conservative surrogate for some kilns.176
---------------------------------------------------------------------------

    \175\ Raw materials enter the upper end of the kiln and move 
counter-current to the combustion gas. Thus, as the raw materials 
are convectively heated in the upper end kiln above the flame zone, 
organic compounds can evolve from trace levels of organics in the 
raw materials. These organic compounds can be measured as 
hydrocarbons, and when only partially oxidized, carbon monoxide. 
This process is not related to combustion of hazardous waste or 
other fuels in the combustion zone at the other end of the kiln.
    \176\ Of course, if a source elects to comply with the carbon 
monoxide standard, then we are sure that it is achieving good 
combustion conditions and good control of organic hazardous air 
pollutants that could be potentially emitted from hazardous waste 
fed into the combustion zone.
---------------------------------------------------------------------------

    Second, requiring both continuous monitoring of carbon monoxide and 
hydrocarbon in the stack is at least somewhat redundant for control of 
organic emissions from combustion of hazardous waste because: (1) 
Hydrocarbons alone are a direct and reliable surrogate for measuring 
the destruction of organic hazardous air pollutants; and (2) carbon 
monoxide is generally a conservative indicator of good combustion 
conditions and thus good control of organic hazardous air pollutants. 
See Part Four, Section IV.B of the preamble for a discussion of our 
approach to using carbon monoxide or hydrocarbons to control organic 
emissions.
    We identify a carbon monoxide level of 100 ppmv and a hydrocarbon 
level of 20 ppmv as floor control for existing sources because they are 
existing federally enforceable standards for hazardous waste burning 
lightweight aggregate kilns. See Sec. 266.104(b) and (c). As current 
rules allow, sources would have the option of complying with either 
limit. Given that these are current rules, all lightweight aggregate 
kilns can currently achieve these emission levels. Thus, we estimate no 
emissions reductions or costs for these floor levels.
    Lightweight aggregate kilns that choose to continuously monitor and

[[Page 52902]]

comply with the carbon monoxide standard must demonstrate during the 
performance test that they are also in compliance with the hydrocarbon 
emission standard. In addition, kilns that monitor carbon monoxide 
alone must also set operating limits on key parameters that affect 
combustion conditions to ensure continued compliance with the 
hydrocarbon emission standard. We developed this modification because 
of some limited data that show a source can produce high hydrocarbon 
emissions while simultaneously producing low carbon monoxide emissions. 
We conclude from this information that it is necessary to confirm the 
carbon monoxide-hydrocarbon emissions relationship for every source 
that selects to monitor carbon monoxide emissions alone. See discussion 
in Part Four, Section IV.B.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? In the April 1996 proposal, we identified beyond-the-floor 
control levels for carbon monoxide and hydrocarbon in the main stack of 
50 ppmv and 6 ppmv, respectively. (61 FR at 17407.) These beyond-the-
floor levels were based on the use of a combustion gas afterburner. We 
indicated in the proposal, however, that this type of beyond-the-floor 
control would be cost prohibitive. Our preliminary estimates suggested 
that going beyond-the-floor for carbon monoxide and hydrocarbons would 
more than double the national costs of complying with the proposed 
standards. We continue to believe that a beyond-the-floor standard for 
carbon monoxide and hydrocarbons based on an afterburner is not 
justified and do not adopt a beyond-the-floor standard for existing 
lightweight aggregate kilns.
    In summary, we adopt the floor emission levels for hydrocarbons, 20 
ppmv, or carbon monoxide, 100 ppmv, as standards in the final rule.
    c. What Is the MACT Floor for New Sources? In the April 1996 NPRM, 
we identified MACT floor control as operating the kiln under good 
combustion practices. Because we were unable to quantify good 
combustion practices, floor control for the single best controlled 
source was the same as for existing sources. We proposed, therefore, a 
floor emission level of 14 ppmv for hydrocarbons and a 100 ppmv limit 
for carbon monoxide. (61 FR at 17409.) In the May 1997 NODA, we 
continued to identify MACT floor control as good combustion practices 
and we took comment on the same emission levels as existing sources: 20 
ppmv for hydrocarbons and 100 ppmv for carbon monoxide. (62 FR at 
24235.)
    In developing the final rule, we considered the comment that the 
rule should allow compliance with either a carbon monoxide standard of 
100 ppmv or a hydrocarbon standard of 20 ppmv. Given that this option 
is available under the existing regulations for new and existing 
sources, we conclude that this represents MACT floor for new sources. 
These emission levels are achieved by operating the kiln under good 
combustion practices to minimize fuel-related hydrocarbons and carbon 
monoxide emissions. As current rules allow, sources would have the 
option of complying with either limit. See Sec. 266.104(b) and (c).
    We also considered site selection based on availability of 
acceptable raw material hydrocarbon content as an approach to establish 
a hydrocarbon emission level at new lightweight aggregate kilns. This 
approach is similar to that done for new hazardous waste burning cement 
kilns at greenfield sites (see discussion above). For cement kilns, we 
finalize a new source floor hydrocarbon emission standard at a level 
consistent with the proposed standard for nonhazardous waste burning 
cement kilns. Because we are planning to issue MACT emission standards 
for nonhazardous waste lightweight aggregate kiln sources, we will 
revisit establishing a hydrocarbon standard at new lightweight 
aggregate kilns at that time so that a hydrocarbon standard, if 
determined appropriate, is consistent for these sources. We are 
deferring this decision to a later date to ensure that hazardous waste 
sources are regulated no less stringently than nonhazardous waste 
lightweight aggregate kilns.
    In summary, we are identifying a carbon monoxide level of 100 ppmv 
and a hydrocarbon level of 20 ppmv as floor control for new sources 
because they are existing federally enforceable standards for hazardous 
waste burning lightweight aggregate kilns. As discussed for existing 
sources above, lightweight aggregate kilns that choose to continuously 
monitor and comply with the carbon monoxide standard must demonstrate 
during the performance test that they are also in compliance with the 
hydrocarbon emission standard.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? In 
the April 1996 proposal, we identified beyond-the-floor emission levels 
for hydrocarbons and carbon monoxide of 6 ppmv and 50 ppmv, 
respectively for new sources. These beyond-the-floor levels were based 
on the use of a combustion gas afterburner. (61 FR at 17409.) We 
indicated in the proposal, however, that beyond-the-floor control was 
not justified due to the significant costs to retrofit kilns with 
afterburner controls. We estimated that going beyond-the-floor for 
hydrocarbons and carbon monoxide would more than double the national 
costs of complying with the proposed standards. We concluded that 
beyond-the-floor standards were not warranted. In the May 1996 NODA, we 
again indicated that a beyond-the-floor standard based on use of an 
afterburner would not be cost-effective and, therefore, justified. As 
discussed above for existing sources, we conclude that a beyond-the-
floor standard for carbon monoxide and hydrocarbons based on use of an 
afterburner would not be justified and do not adopt a beyond-the-floor 
standard for new lightweight aggregate kilns. (62 FR 24235.)
    In summary, we adopt the floor emission levels for hydrocarbons, 20 
ppmv, or carbon monoxide, 100 ppmv, as standards in the final rule.
9. What Are the Standards for Destruction and Removal Efficiency?
    We establish a destruction and removal efficiency (DRE) standard 
for existing and new lightweight aggregate kilns to control emissions 
of organic hazardous air pollutants other than dioxins and furans. 
Dioxins and furans are controlled by separate emission standards. See 
discussion in Part Four, Section IV.A. The DRE standard is necessary, 
as previously discussed, to complement the carbon monoxide and 
hydrocarbon emission standards, which also control these hazardous air 
pollutants.
    The standard requires 99.99 percent DRE for each principal organic 
hazardous constituent (POHC), except that 99.9999 percent DRE is 
required if specified dioxin-listed hazardous wastes are burned. These 
wastes--F020, F021, F022, F023, F026, and F027--are listed as RCRA 
hazardous wastes under part 261 because they contain high 
concentrations of dioxins.
    a. What Is the MACT Floor for Existing Sources? Existing sources 
are currently subject to DRE standards under Sec. 266.104(a) that 
require 99.99 percent DRE for each POHC, except that 99.9999 percent 
DRE is required if specified dioxin-listed hazardous wastes are burned. 
Accordingly, these standards represent MACT floor. Since all hazardous 
waste lightweight aggregate kilns must currently achieve these DRE 
standards, they represent floor control.
    b. What Are Our Beyond-the-Floor Considerations for Existing 
Sources? Beyond-the-floor control would be a requirement to achieve a 
higher

[[Page 52903]]

percentage DRE, for example, 99.9999 percent DRE for POHCs for all 
hazardous wastes. A higher DRE could be achieved by improving the 
design, operation, or maintenance of the combustion system to achieve 
greater combustion efficiency.
    Even though the 99.99 percent DRE floor is an existing RCRA 
standard, a substantial number of existing hazardous waste combustors 
are not likely to be routinely achieving 99.999 percent DRE, however, 
and most are not likely to be achieving 99.9999 percent DRE. 
Improvements in combustion efficiency will be required to meet these 
beyond-the-floor DREs. Improved combustion efficiency is accomplished 
through better mixing, higher temperatures, and longer residence times. 
As a practical matter, most combustors are mixing-limited and may not 
easily achieve 99.9999 percent DRE. For a less-than-optimum burner, a 
certain amount of improvement may typically be accomplished by minor, 
relatively inexpensive combustor modifications--burner tuning 
operations such as a change in burner angle or an adjustment of swirl--
to enhance mixing on the macro-scale. To achieve higher DREs, however, 
improved mixing on the micro-scale may be necessary. This involves 
significant, energy intensive and expensive modifications such as 
burner redesign and higher combustion air pressures. In addition, 
measurement of such DREs may require increased spiking of POHCs and 
more sensitive stack sampling and analysis methods at added expense.
    Although we have not quantified the cost-effectiveness of a beyond-
the-floor DRE standard, it would not appear to be cost-effective. For 
reasons discussed above, the cost of achieving each successive order-
of-magnitude improvement in DRE will be at least constant, and more 
likely increasing. Emissions reductions diminish substantially, 
however, with each order of magnitude improvement in DRE. For example, 
if a source were to emit 100 gm/hr of organic hazardous air pollutants 
assuming zero DRE, it would emit 10 gm/hr at 90 percent DRE, 1 gm/hr at 
99 percent DRE, 0.1 gm/hr at 99.9 percent DRE, 0.01 gm/hr at 99.99 
percent DRE, and 0.001 gm/hr at 99.999 percent DRE. If the cost to 
achieve each order of magnitude improvement in DRE is roughly constant, 
the cost-effectiveness of DRE decreases with each order of magnitude 
improvement in DRE. Consequently, we conclude that this relationship 
between compliance cost and diminished emissions reductions suggests 
that a beyond-the-floor standard is not warranted in light of the 
resulting, poor cost-effectiveness.
    c. What Is the MACT Floor for New Sources? The single best 
controlled source, and all other hazardous waste lightweight aggregate 
kilns, are subject to the existing RCRA DRE standard under 
Sec. 266.104(a). Accordingly, we adopt this standard of 99.99% DRE for 
most wastes and 99.9999% DRE for dioxin listed wastes as the MACT floor 
for new sources.
    d. What Are Our Beyond-the-Floor Considerations for New Sources? As 
discussed above, although we have not quantified the cost-effectiveness 
of a more stringent DRE standard, diminishing emissions reductions with 
each order of magnitude improvement in DRE suggests that cost-
effectiveness considerations would likely come into play. We conclude 
that a beyond-the-floor standard is not warranted.

Part Five: Implementation

I. How Do I Demonstrate Compliance with Today's Requirements?

    If you operate a hazardous waste burning incinerator, cement kiln, 
or lightweight aggregate kiln, you are required to comply with the 
standards and requirements in today's rule at all times, with one 
exception. If you are not feeding hazardous waste to the combustion 
device and if hazardous waste does not remain in the combustion 
chamber, these rules do not apply under certain conditions discussed 
below. You must comply with all of the notification requirements, 
emission standards, and compliance and monitoring provisions of today's 
rule by the compliance date, which is three years after September 30, 
1999. As referenced later, the effective date of today's rule is 
September 30, 1999. The compliance and general requirements of this 
rule are discussed in detail in the follow sections. Also, we have 
included the following time line that will assist you in determining 
when many of the notifications and procedures, discussed in the later 
sections of this part, are required to be submitted or accomplished.
A. What Sources Are Subject to Today's Rules?
    Sources affected by today's rule are defined as all incinerators, 
cement kilns and lightweight aggregate kilns burning hazardous waste 
on, or following September 30, 1999. This definition is essentially the 
same as we proposed in the April 1996 NPRM. Comments, regarding this 
definition, suggested that there was confusion as to when and under 
what conditions you would be subject to today's hazardous waste MACT 
regulations. In this rule, we specify that once you are subject to 
today's regulations, you remain subject to these regulations until you 
comply with the requirements for sources that permanently suspend 
hazardous waste burning operations, as discussed later.
    However, just because you are subject to today's regulations does 
not mean that you must comply with the emission standards or operating 
limits at all times. In later sections of today's rule, we identify 
those limited periods and situations in which compliance with today's 
emission standards and operating limits may not be required.
1. What Is an Existing Source?
    Today's rule clarifies that existing sources are sources that were 
constructed or under construction on the publication date for our 
NPRM---April 19, 1996. This is consistent with the current regulatory 
definition of existing sources, but is different from the definition in 
our April 1996 
NPRM. In the April 1996 NPRM, we defined existing sources as those 
burning hazardous waste on the proposal date (April 19, 1996) and 
defined new sources as sources that begin burning hazardous waste after 
the proposal date. Commenters note that the proposed definition of new 
sources is not consistent with current regulations found in 40 CFR part 
63 or the Clean Air Act. Commenters also believe that our definition 
does not consider the intent of Congress, i.e., to require only those 
sources that incur significant costs during upgrade or modification to 
meet the most stringent new source emission standards. Commenters note 
that a large number of sources that are currently not burning hazardous 
waste could modify their combustion units to burn hazardous waste at a 
cost that would not surpass the reconstruction threshold and therefore 
they should not be required to meet the new source emission standards. 
Commenters suggest we use the statutory definition of an existing 
source found at section 112(a)(4) of the CAA and codified at 40 CFR 
63.2. We agree with commenters and therefore adopt the definition of an 
existing source found at 40 CFR 63.2.
2. What Is a New Source?
    Today's rule clarifies that new sources are those that commence 
construction or meet the definition of a reconstructed source following 
the proposal date of April 19, 1996. In the proposal, we define new 
sources as those that newly begin to burn hazardous waste after the 
proposal date. However, as noted earlier, commenters object to the

[[Page 52904]]

proposed definition because of conflicts with the statutory language of 
the CAA and the current definition found in MACT regulations. In the 
CAA regulations, we define new sources as those that are newly 
constructed or reconstructed after a rule is proposed. Here again, we 
agree with commenters and adopt the current regulatory definition of 
new sources. We also adopt the CAA definition of reconstruction. This 
definition also is generally consistent with the RCRA definition of 
reconstruction and should avoid any confusion regarding what standards 
apply to reconstructed sources.
B. How Do I Cease Being Subject to Today's Rule?
    Once you become an affected source as defined in Sec. 63.2, you 
remain an affected source until you: (1) Cease hazardous waste burning 
operations, (i.e., hazardous waste is not in the combustion chamber); 
(2) notify the Administrator, and other appropriate regulatory 
authorities, that you have ceased hazardous waste burning operations; 
and (3) begin complying with other applicable MACT standards and 
regulations, if any, including notifications, monitoring and 
performance tests requirements.
    If you permanently stop burning hazardous waste, the RCRA 
regulations require you to initiate closure procedures within three 
months of the date you received your last shipment of hazardous waste, 
unless you have obtained an extension from the Administrator. The 
requirement to initiate closure pertains to your RCRA status and should 
not be a barrier to operational changes that affect your regulatory 
status under today's MACT requirements. This approach is a departure 
from the requirements proposed in the April 1996 NPRM, but is 
consistent with the approach we identified in the May 1997 NODA.
    Once you permanently stop burning hazardous waste, you may only 
begin burning hazardous waste under the procedures outlined for new or 
existing sources that become affected sources following September 30, 
1999. See later discussion.
C. What Requirements Apply If I Temporarily Cease Burning Hazardous 
Waste?
    Under today's rule, if you temporarily cease burning hazardous 
waste for any reason, you remain subject to today's requirements as an 
affected source. However, even as an affected source, you may not have 
to comply with the emission standards or operating limits of today's 
rule when hazardous waste is not in the combustion chamber. Today's 
standards, associated operating parameter limits, and monitoring 
requirements are applicable at all times unless hazardous waste is not 
in the combustion chamber and either: (1) You elect to comply with 
other MACT standards that would be applicable if you were not burning 
hazardous waste (e.g. the nonhazardous waste burning Portland Cement 
Kiln MACT, the nonhazardous waste burning lightweight aggregate kiln 
MACT (Clay Products Manufacturing), or the Industrial Incinerator 
MACT); or (2) you are in a startup, shutdown, or malfunction mode of 
operation. We note that until these alternative MACT standards are 
promulgated, you need to comply only with other existing applicable air 
requirements if any. This approach is consistent with the current RCRA 
regulatory approach for hazardous waste combustion sources, but differs 
from our April 1996 proposed approach.
    In our April 1996 NPRM, we proposed that sources always be subject 
to all of the proposed regulatory requirements, regardless of whether 
hazardous waste was in the combustion chamber. Commenters question the 
legitimacy of this requirement because the requirement was: (1) more 
stringent than current requirements; (2) not based on CAA statutory 
authority; and (3) contrary to current allowances under current MACT 
general provisions.
    In response, we agree with commenters on issues (1) and (3) above. 
However, we disagree with commenters on issue number (2). The CAA does 
not allow sources to be subject to multiple MACT standards 
simultaneously. Because current CAA regulations also allow sources to 
modify their operations such that they can become subject to different 
MACT rules so long as they provide notification to the Administrator, 
our proposed approach appears to further complicate a situation that it 
was intended to resolve. One of the main reasons we proposed to subject 
hazardous waste burning sources to the final standards at all times was 
to eliminate the ability of sources to arbitrarily switch between 
regulation as a hazardous waste burning source and regulation as a 
nonhazardous waste burning source. We were concerned about the 
compliance implications associated with numerous notifications to the 
permitting authority to govern operations that may only occur for a 
short period of time. However, our concern appears unfounded because 
the MACT general provisions currently allow sources to change their 
regulatory status following notification, and we cannot achieve this 
goal without restructuring the entire MACT program. Therefore, 
consistent with the current program, we adopt an approach that allows a 
source to comply with alternative compliance requirements, while 
remaining subject to today's rule. This regulatory approach eliminates 
the reporting requirements and compliance determinations we intended to 
avoid with our proposed approach, while preserving the essence of the 
current RCRA approach, which applies more stringent emissions standards 
when hazardous waste is in the combustor.
1. What Must I Do to Comply with Alternative Compliance Requirements?
    If you wish to comply with alternative compliance requirements, you 
must: (1) Comply with all of the applicable notification requirements 
of the alternative regulation; (2) comply with all the monitoring, 
record keeping and testing requirements of the alternative regulation; 
(3) modify your Notice Of Compliance (or Documentation of Compliance) 
to include the alternative mode(s) of operation; and (4) note in your 
operating record the beginning and end of each period when complying 
with the alternative regulation.
    If you intend to comply with an alternative regulation for longer 
than three months, then you also must comply with the RCRA requirements 
to initiate RCRA closure. You may be able to obtain an extension of the 
date you are required to begin RCRA closure by submitting a request to 
the Administrator.
2. What Requirements Apply If I Do Not Use Alternative Compliance 
Requirements?
    If you elect not to use the alternative requirements for compliance 
during periods when you are not feeding hazardous waste, you must 
comply with all of the operating limits, monitoring requirements, and 
emission standards of this rule at all times.177 However, if 
you are a kiln operator, you also may be able to obtain and comply with 
the raw material variance discussed later.
---------------------------------------------------------------------------

    \177\ The operating requirements do not apply during startup, 
shutdown, or malfunction provided that hazardous waste is not in the 
combustion chamber. See the discussion below in the text.
---------------------------------------------------------------------------

D. What Are the Requirements for Startup, Shutdown and Malfunction 
Plans?
    Sources affected by today's rule are subject to the provisions of 
40 CFR 63.6 with regard to startup, shutdown and malfunction plans. 
However, the plan applies only when hazardous waste is

[[Page 52905]]

not in the combustion chamber. If you exceed an operating requirement 
during startup, shutdown, or malfunction when hazardous waste is in the 
combustion chamber, your exceedance is not excused by following your 
plan. If you exceed an operating requirement during startup, shutdown, 
or malfunction when hazardous waste is not in the combustion chamber, 
you must follow your startup, shutdown, and malfunction plan to come 
back into compliance as quickly as possibly, unless you have elected to 
comply with the requirements of alternative section 112 or 129 
regulations that would apply if you did not burn hazardous waste. 
Failure to comply with the operating requirements to follow your 
startup, shutdown, and malfunction plan during the applicable periods 
is representative of a violation and may subject you to appropriate 
enforcement action.
    In the April 1996 NPRM (see 63 FR at 17449), we proposed that 
startup, shutdown, and malfunction plans would not be applicable to 
sources affected by the proposed rule because affected sources must be 
in compliance with the standards at all times hazardous waste is in the 
combustion chamber. We reasoned that hazardous waste could not be fired 
unless you were in compliance with the emission standards and operating 
requirements, and stated that the information contained in the plan and 
the purpose of the plan was not intended to apply to sources affected 
by this rule.
    In response, commenters state that startup, shutdown, and 
malfunction plans are appropriate for hazardous waste burning sources 
because malfunctioning operations are going to occur, and these plans 
are designed to reestablish compliant or steady state operations as 
quickly as possible. Furthermore, commenters maintain that because 
sources must prepare and follow facility-specific plans to address 
situations that could lead to increased emissions, rather than just 
note such an occurrence in the operating record, the public and we are 
better assured that the noncompliant operations are being remedied 
rather than awaiting for an after-the-fact enforcement action. 
Commenters also note that hazardous waste burning sources are no 
different than other MACT sources who are required to use such plans.
    After considering comments, we agree with commenters that startup, 
shutdown, and malfunction plans are valuable compliance tools and 
should be applicable to hazardous waste burning sources. However, we 
are concerned that some sources may attempt to use startup, shutdown, 
and malfunction plans to circumvent enforcement actions by claiming 
they were never out of compliance if they followed their plan. 
Therefore, we restrict the applicability of startup, shutdown, and 
malfunction plans to periods when hazardous waste is not in the 
combustion chamber. This restriction addresses the concern that 
operations under startup, shutdown, and malfunction could lead to 
increased emissions of hazardous air pollutants.
    We considered whether to specifically prohibit sources from feeding 
hazardous waste during periods of startup and shutdown. However, we 
decided not to adopt this requirement because of a potential regulatory 
problem. The requirement could have inadvertently subjected sources 
that experience unscheduled shutdowns to enforcement action if 
hazardous waste remained in the combustion chamber during the shutdown 
process even if operating requirements were not exceeded. Additionally, 
we decided that the prohibition was unnecessary because performance 
test protocols restrict the operations of all sources when determining 
operating parameter limits. The following factors are pertinent in this 
regard: (1) Sources are required to be in compliance with their 
operating parameter limits at all times hazardous waste is in the 
combustion chamber; (2) operating parameter limits are determined 
through a performance test which must be performed under steady-state 
conditions (see Sec. 63.1207(g)(1)(iii)); and (3) periods of startup 
and shutdown are not steady state conditions and therefore operating 
parameter limits determined through performance testing would not be 
indicative of those periods. Accordingly, burning hazardous waste 
during startup or shutdown would significantly increase the potential 
for a source to exceed an operating parameter limit, and we expect that 
sources would be unwilling to take that chance as a practical matter.
E. What Are the Requirements for Automatic Waste Feed Cutoffs?
    As proposed, you must operate an automatic waste feed cutoff system 
that immediately and automatically cuts off hazardous waste feed to the 
combustion device when:
    (1) Any of the following are exceeded: Operating parameter limits 
specified in Sec. 63.1209; an emission standard monitored by a 
continuous emissions monitoring system; and the allowable combustion 
chamber pressure; (2) The span value of any continuous monitoring 
system, except a continuous emissions monitoring system, is met or 
exceeded; (3) A continuous monitoring system monitoring an operating 
parameter limit under Sec. 63.1209 or emission level malfunctions; or 
(4) Any component of the automatic waste feed cutoff system fails.
    These requirements are provided at Sec. 63.1206(c)(3). The system 
must be fully functional on the compliance date and interlocked with 
the operating parameter limits you specify in the Document of 
Compliance (as discussed later) as well as the other parameters listed 
above.
    Also as proposed, after an automatic waste feed cutoff, you must 
continue to route combustion gases through the air pollution control 
system and maintain minimum combustion chamber temperature as long as 
hazardous waste remains in the combustion chamber. These requirements 
minimize emissions of regulated pollutants, including organic hazardous 
air pollutants, that could result from a perturbation caused by the 
waste feed cutoff. Additionally, you must continue to calculate all 
rolling averages and cannot restart feeding hazardous waste until all 
operating limits are within allowable levels.
    Additionally, as currently required for BIFs, we proposed that the 
automatic waste feed cutoff system and associated alarms must be tested 
at least once every seven days. This must be done when hazardous waste 
is burned to verify operability, unless you document in the operating 
record that weekly inspections will unduly restrict or upset operations 
and that less frequent inspections will be adequate. At a minimum, you 
must conduct operational testing at least once every 30 days.
    Commenters express the following concerns with the proposed 
automatic waste feed cutoff requirements: (1) Violations of the 
automatic waste feed cutoff linked operating parameters should not 
constitute a violation of the associated emission standard; (2) 
apparent redundancy exists between the proposed MACT requirements with 
the current RCRA requirements; (3) the proposed automatic waste feed 
cutoff requirements are inappropriate for all sources; and (4) 
uncertainty exists about how ``instantaneous'' is defined with regard 
to the nature of the automatic waste feed cutoff requirement.
    We address issue (1) later in this section. With respect to issue 
(2), our permitting approach (i.e., a single CAA title V permit to 
control all stack emissions) minimizes the potential redundancy of two 
permitting programs.
    In response to issue (3), we acknowledge that not all sources may 
be capable of setting operating limits or

[[Page 52906]]

continuously monitoring all of the prescribed operating parameters due 
to unique design characteristics inherent to individual units. However, 
you may take advantage of the provisions found in Sec. 63.8(f) which 
allow you to request the use of alternative monitoring techniques. See 
also Sec. 63.1209(g)(1).
    For issue (4), commenters express concern that requiring an 
immediate, instantaneous, and abrupt cutoff of the entire waste feed 
can cause perturbations in the combustion system that could result in 
exceedances of additional operating limits. We agree with commenters 
that a ramping down of the waste feedrate could preclude this problem 
in many cases and in the final rule allow a one-minute ramp down for 
pumpable wastes. To ensure that your ramp down procedures are bona fide 
and not simply a one-minute delay ending in an abrupt cutoff, you must 
document your ramp down procedures in the operating and maintenance 
plan. The procedures must specify that the ramp down begins immediately 
upon initiation of automatic waste feed cutoff and provides for a 
gradual ramp down of the hazardous waste feed. Note that if an emission 
standard or operating limit is exceeded during the ramp down, you 
nonetheless have failed to comply with the emission standards or 
operating requirements. The ramp down is not applicable, however, if 
the automatic waste feed cutoff is triggered by an exceedance of any of 
the following operating limits: minimum combustion chamber temperature; 
maximum hazardous waste feedrate; or any hazardous waste firing system 
operating limits that may be established for your combustor on a site-
specific basis. This is because these operating conditions are 
fundamental to proper combustion of hazardous waste and an exceedance 
could quickly result in an exceedance of an emission standard. We 
restrict the ramp down to pumpable wastes because: (1) Solids are often 
fed in batches where ramp down is not relevant (i.e., ramp down is only 
relevant to continuously fed wastes); and (2) incinerators burning 
solids also generally burn pumpable wastes and ramping down on 
pumpables only should preclude the combustion perturbations that could 
occur if all wastes were abruptly cutoff.
    Finally, with respect to issue number (1), if you exceed an 
operating parameter limit while hazardous waste is in the combustion 
chamber, then you have failed to ensure compliance with the associated 
emission standard. Accordingly, appropriate enforcement action on the 
exceedance can be initiated to address the exceedance. This enforcement 
process is consistent with current RCRA enforcement procedures 
regarding exceedances of operating parameter limits. However, as 
commenters note, we acknowledge that an exceedance of an operating 
parameter limit does not necessarily demonstrate that an associated 
emissions standard is exceeded. Nevertheless, in general, an exceedance 
of an operating parameter limit in a permit or otherwise required is an 
actionable event for enforcement purposes.
    Operating parameter limits are developed through performance tests 
that successfully demonstrate compliance with the standards. If a 
source exceeds an operating limit set during the performance test to 
show compliance with the standard, the source can no longer assure 
compliance with the associated standard. Furthermore, these operating 
parameter limits appear in enforceable documents, such as your NOC or 
your title V permit.
F. What Are the Requirements of the Excess Exceedance Report?
    In today's rule, we finalize the requirement to report to the 
Administrator when you incur 10 exceedances of operating parameter 
limits or emissions standards monitored with a continuous emissions 
monitoring system within a 60 day period. See Sec. 63.1206(c)(3)(vi). 
If a source has 10 exceedances within the 60 day period, the 60 day 
period restarts after the notification of the 10th exceedance. This 
provision is intended to identify sources that have excess exceedances 
due to system malfunction or performance irregularities. This 
notification requirement both highlights the source to regulatory 
officials and provides an added impetus to the facility to correct the 
problem(s) that may exist to limit future exceedances. For example, a 
source that must submit an excess exceedance report may be unable to 
operate under its current operating limits, which suggests that the 
source may need to perform a new comprehensive performance test to 
establish more appropriate operating limits.
    We discussed this provision in the April 1996 NPRM. Some commenters 
may have misunderstood our proposal while others felt that 10 
exceedances in sixty days was not a feasible number to set the 
reporting limit. Other commenters state that an industry wide MACT-like 
analysis is necessary to identify an achievable or appropriate number 
of exceedances upon which to set the reporting limit.
    We disagree with such comments. A MACT-like analysis is not called 
for in this case because this requirement is not an emission standard. 
This is a notification procedure that is a compliance tool to identify 
sources that cannot operate routinely in compliance with their 
operating parameter limits and emissions standards monitored with a 
continuous emissions monitoring system. Ideally, all sources should 
operate in compliance with all the standards and operating parameter 
limits at all times. Because, in the past, sources have been able to 
exceed their operating limits without having to notify the Agency, this 
does not mean that we condone, expect, or are unconcerned with such 
activity. In fact, the main reason we require this notification is 
because such activity exists to the current extent and because the 
Regions and States have identified it as a problem. We select 10 
exceedances in sixty days as the value that triggers reporting after 
discussions with Regional and State permit writers. Our discussions 
revealed that many hazardous waste combustion sources are required to 
notify regulatory officials following a single exceedance of an 
operating limit, while others don't have any reporting requirements 
linked to exceedances. Regions and States noted that because there is 
no current regulatory requirement for exceedance notifications, it is 
very difficult to require such notifications on a site-specific basis. 
Following these discussions, we contemplated requiring a notification 
following a single exceedance, but decided that the such a reporting 
limit might unnecessarily burden regulatory officials with reports from 
facilities that have infrequent exceedances. Therefore, our approach of 
10 exceedances in a 60 day period is a reasonably implementable limit 
and is not overly burdensome. Adopting this approach achieves an 
appropriate balance between burden on facilities and regulators and the 
need to identify underlying operational problems that may present 
unacceptable risks to the public and environment.
    To reiterate, this provision applies to any 10 exceedances of 
operating parameter limits or emission standards monitored with a 
continuous emissions monitoring system.
G. What Are the Requirements for Emergency Safety Vent Openings?
    In today's rule, we finalize requirements that govern the operation 
of emergency safety vents. See Sec. 63.1206(c)(4). These requirements: 
clarify the regulatory status of emergency safety vent events; require

[[Page 52907]]

development of an emergency safety vent operating plan that specifies 
procedures to minimize the frequency and duration of emergency safety 
vent openings; and specify procedures to follow when an emergency 
safety vent opening occurs.
    Key requirements regarding emergency safety vent openings include:
    (1) Treatment of combustion gases--As proposed, you must route 
combustion system off-gases through the same emission control system 
used during the comprehensive performance test. Any bypass of the 
pollution control system is considered an exceedance of operating 
limits defined in the Documentation of Compliance (DOC) or Notification 
of Compliance (NOC);
    (2) Emergency safety vent operating plan--As proposed, if you use 
an emergency safety vent in your system design, you must develop and 
submit with the DOC and NOC an emergency safety vent operating plan 
that outlines the procedures you will take to minimize the frequency 
and duration of emergency safety vent openings and details the 
procedure you will follow during and after an emergency safety vent 
opening; and
    (3) Emergency safety vent reporting requirements--As proposed, if 
you operate an emergency safety vent, you must submit a report to the 
appropriate regulatory officials within five days of an emergency 
safety vent opening. In that report, you must detail the cause of the 
emergency safety vent opening and provide information regarding 
corrective measures you will institute to minimize such events in the 
future.
    Commenters on the April 1996 NPRM (61 FR at 17440) state that 
emergency safety vent openings are safety devices designed to prevent 
catastrophic failures, safeguard the unit and operating personnel from 
pressure excursions and protect the air pollution control train from 
high temperatures and pressures. They suggest that restricting these 
operations is contrary to common sense. Furthermore, they state that 
emergency safety vent openings are most often due to local power 
outages and fluctuations in water flows going to the air pollution 
equipment. Commenters believe that emergency safety vent openings 
should not be considered violations and that not every emergency safety 
vent opening should be reportable for a variety of reasons including:
--Emergency safety vent openings have not been shown to be acutely 
hazardous. A study finds that they will not have any short-term impact 
on the health of workers on-site or residents of the nearby off-site 
community.
--Proper use of emergency safety vent systems minimizes the potential 
for impacts on operators and the neighboring public.
--Many emergency safety vents are downstream of the secondary 
combustion chamber and thus have low organic emissions.
--Some facilities have emergency safety vents connected to the air 
pollution control system and should be considered in compliance as long 
as the continuous emissions monitoring systems monitoring data does not 
indicate an exceedance.

    Commenters propose several alternatives:

--Recording emergency safety vent openings (including the time, 
duration and cause of each event) in the operating record, available to 
the Administrator, or any authorized representative, upon request.
--Making emergency safety vent openings a part of startup, shutdown, 
malfunction and abatement plans.
--Reporting openings that occurs more frequently than once in any 90 
day period, whereupon the Administrator may require corrective 
measures.
--Reporting only emergency safety vent openings in excess of 10 in a 60 
day period.
--Conditions relating to an emergency safety vent operation should be a 
part of the site-specific permit.
--Rely on the present RCRA permit process which provides the 
opportunity for permit writers and hazardous waste combustion device 
owner/operators to review emergency safety vent system designs.

    We agree that emergency safety vents are necessary safety devices 
for some incinerator designs that are intended to safeguard employees 
and protect the equipment from the dangers associated with system over-
pressures or explosions. However, simply because emergency safety vents 
are necessary safety devices for some incinerator designs in the event 
of a major malfunction does not mean that their routine use is 
acceptable. We cannot overlook an event when combustion gases are 
emitted into the environment prior to proper treatment by the pollution 
control system. Therefore, an emergency safety vent opening is evidence 
that compliance is not being achieved. Nonetheless, we expect sources 
to continue to use safety vents when the alternative could be a 
catastrophic failure and substantial liability even though opening the 
vent is evidence of failure to comply with the emission standards.
    Today's requirements are based on the fundamental need to ensure 
protection of human health and the environment against unquantified and 
uncontrolled hazardous air pollutant emissions. We do not agree that a 
change in the proposed emergency safety vent reporting requirement is 
warranted. These events are indicative of serious operational problems, 
and each event should be reported and investigated to reduce the 
potential of future similar events. As for including the emergency 
safety vent operating plan in the source-specific startup, shutdown, 
and malfunction plan, we see no reason to discourage that practice 
provided that a combined plan specifically addresses the events 
preceding and following an emergency safety vent opening.
H. What Are the Requirements for Combustion System Leaks?
    You must prevent leaks of gaseous, liquid or solid materials from 
the combustion system when hazardous waste is being fed to or remains 
in the combustion chamber. To demonstrate compliance with this 
requirement you must either: (1) Maintain the combustion system 
pressure lower than ambient pressure at all times; (2) totally enclose 
the system; or (3) gain approval from the Administrator to use an 
alternative approach that provides the same level of control achieved 
by options 1 and 2.
    Currently, these requirements exist for all sources under RCRA 
regulations. Many commenters question whether they were capable of 
meeting this requirement for various technical reasons. We acknowledge 
that certain situations may exist that prevent or limit a source from 
instantaneously monitoring pressure inside the combustion system, but 
in such situations, we can approve alternative techniques (under 
Sec. 63.1209(g)(1)) that allow sources to achieve the objectives of the 
requirements. Because this requirement is identical to the current RCRA 
requirements, and because we have specifically provided alternative 
techniques to demonstrate compliance, modifications to this provision 
are not warranted.
I. What Are the Requirements for an Operation and Maintenance Plan?
    You must prepare and at all times operate according to a operation 
and maintenance plan that describes in detail procedures for operation, 
inspection, maintenance, and corrective measures for all components of 
the combustor, including associated pollution control equipment, that 
could affect emissions of regulated hazardous

[[Page 52908]]

air pollutants. The plan must prescribe how you will operate and 
maintain the combustor in a manner consistent with good air pollution 
control practices for minimizing emissions at least to the levels 
achieved during the comprehensive performance test. You must record the 
plan in the operating record. See Sec. 63.1206(c)(7)(i).
    In addition, if you own or operate a hazardous waste incinerator or 
hazardous waste burning lightweight aggregate kiln equipped with a 
baghouse, your operation and maintenance plan for the baghouse must 
include a prescribed inspection schedule for baghouse components and 
use of a bag leak detection system to identify malfunctions. This 
baghouse operation and maintenance plan must be submitted to the 
Administrator with the initial comprehensive performance test for 
review and approval. See Sec. 63.1206(c)(7)(ii).
    We require an operation and maintenance plan to implement the 
provisions of Sec. 63.6(e). That paragraph requires you to operate and 
maintain your source in a manner consistent with good air pollution 
control practices for minimizing emissions. That paragraph, as all 
Subpart A requirements, applies to all MACT sources unless requirements 
in the subpart for a source category state otherwise. In addition, 
Sec. 63.6(e)(2) states that the Administrator will determine whether 
acceptable operation and maintenance procedures are used by reviewing 
information including operation and maintenance procedures and records. 
Thus, paragraph (e)(2) effectively requires you to develop operation 
and maintenance procedures. Consequently, explicitly requiring you to 
develop an operation and maintenance plan is a logical outgrowth of the 
proposed rule.
    Similarly, although we did not prescribe baghouse inspection 
requirements or require a bag leak detection system at proposal for 
incinerators and lightweight aggregate kilns, this is a logical 
outgrowth of the proposed rule. Section 63.6(e) requires sources to 
operate and maintain emission control equipment in a manner consistent 
with good air pollution control practices for minimizing emissions. 
Inspection of baghouse components is required to provide adequate 
maintenance, and a bag leak detection system is a state-of-the-art 
monitoring system that identifies major baghouse malfunctions. Absent 
use of a particulate matter CEMS or opacity monitor, use of a bag leak 
detection system is an essential monitoring approach to ensure that the 
baghouse continues to operate in a manner consistent with good air 
pollution control practices. Bag leak detection systems are required 
under the MACT standards for secondary lead smelters. See Sec. 63.548. 
We have also proposed to require them as MACT requirements for several 
other source categories including primary lead smelters (see 63 FR 
19200 (April 17, 1998)) and primary copper smelters (see 63 FR 19581 
(April 20, 1998)). In addition, we have published a guidance document 
on the installation and use of bag leak detection systems: USEPA, 
``Fabric Filter Bag Leak Detection,'' September 1997, EPA-454/R-98-015. 
Thus, although not explicitly required at proposal, a requirement to 
use bag leak detection systems is a logical outgrowth of the (proposed) 
requirements of Sec. 63.6(e).
    We are not prescribing a schedule for inspection of baghouse 
components or requiring a bag leak detection system for cement kilns 
because cement kilns must use a continuous opacity monitoring system 
(COMS) to demonstrate compliance with an opacity standard. A COMS is a 
better indicator of baghouse performance than a bag leak detection 
system. We could not use COMS for incinerators and lightweight 
aggregate kilns, however, because we do not have data to identify an 
opacity standard that is achievable by MACT sources (i.e., sources 
using MACT control and achieving the particulate matter standard).
    We are not specifying the type of sensor that must be used other 
than: (1) The system must be certified by the manufacturer to be 
capable of detecting particulate matter emissions at concentrations of 
1.0 milligram per actual cubic meter; and (2) the sensor must provide 
output of relative particulate matter loadings. Several types of 
instruments are available to monitor changes in particulate emission 
rates for the purpose of detecting fabric filter bag leaks or similar 
failures. The principles of operation of these instruments include 
electrical charge transfer and light scattering. The guidance document 
cited above applies to charge transfer monitors that use 
triboelectricity to detect changes in particle mass loading, but other 
types of monitors may be used. Specifically, opacity monitors may be 
used.
    The economic impacts of requiring fabric filter bag leak detection 
systems are minimal. These systems are relatively inexpensive. They 
cost less than $11,000 to purchase and install. Further, we understand 
that most hazardous waste burning lightweight aggregate kilns are 
already equipped with triboelectric sensors. Finally, there are few 
hazardous waste incinerators that are currently equipped with fabric 
filters.

II. What Are the Compliance Dates for this Rule?

A. How Are Compliance Dates Determined?
    In today's rule, as with other MACT rules, we specify the 
compliance date and then provide you additional time to demonstrate 
compliance through performance testing. Generally, you must be in 
compliance with the emission standards on September 30, 2002 unless you 
are granted a site-specific extension of the compliance date of up to 
one year. By September 30, 2002, you must complete modifications to 
your unit and establish preliminary operating limits, which must be 
included in the Documentation of Compliance (DOC) and recorded in the 
operating record. Following the compliance date you have up to 180 days 
to complete the initial comprehensive performance test and an 
additional 90 days to submit the results of the performance test in the 
Notification of Compliance (NOC). In the NOC, you also must certify 
compliance with applicable emission standards and define the operating 
limits that ensure continued compliance with the emission standards.
    In the April 1996 NPRM, we proposed that sources comply with all 
the substantive requirements of the rule on the compliance date. This 
required sources to conduct their performance test as well as submit 
results in the NOC by the compliance date. The compliance date 
discussed in the April 1996 NPRM contained a statutory limitation of 
three years following the effective date of the final rule (i.e., the 
publication date of the final rule) with the possibility of a site-
specific extension of up to one year for the installation of controls 
to comply with the final standards, or to allow for waste minimization 
reductions.
    In the May 1997 NODA, we acknowledged that the April 1996 NPRM 
definition of compliance date and our approach to implementation 
created a number of unforseen difficulties (see 63 FR at 24236). 
Commenters note that the proposed compliance date definition and the 
ramifications of noncompliance create the potential for an 
unnecessarily large number of source shut-downs due to an insufficient 
period to perform all the required tasks. Commenters recommend we 
follow the general provisions applicable to all MACT regulated sources, 
which allow sources to demonstrate compliance through

[[Page 52909]]

performance testing and submission of emission test results up to 270 
days following the compliance date.
    In the May 1997 NODA, we outlined an approach that allowed 
facilities to use the Part 63 general approach, which requires sources 
to complete performance testing within 180 days of the compliance date 
and submit test results 90 days after completing the performance 
test.178 Today, we adopt this approach to foster consistent 
implementation of this rule as a CAA regulation.
---------------------------------------------------------------------------

    \178\ The general provisions of part 63 allow for 180 days after 
the compliance date to conduct a performance test and 60 days to 
submit its results to the appropriate regulatory agency. However, as 
commenters note, dioxin/furan analyses can require 90 days to 
complete. Therefore, the time allowed for submission of test results 
should be extended to 90 days, increasing the total time following 
the compliance date to 270 days. We agree with commenters and 
increase the time allowed for submission of test results from 60 to 
90 days.
---------------------------------------------------------------------------

    Your individual dates for: (1) Compliance; (2) comprehensive 
performance testing; (3) submittal of test results; and (4) submittal 
of your NOC and title V permit requests depend on whether you were an 
existing source on April 19, 1996. Compliance dates for existing and 
new sources are discussed in the following two subsections.
B. What Is the Compliance Date for Sources Affected on April 19, 1996?
    The compliance date for all affected sources constructed, or 
commencing construction or reconstruction before April 19, 1996 is 
September 30, 2002.
C. What Is the Compliance Date for Sources That Become Affected After 
April 19, 1996?
    If you began construction or reconstruction after April 19, 1996, 
your compliance date is the latter of September 30, 1999 or the date 
you commence operations. If today's final emission standards are less 
stringent or as stringent as the standards proposed on April 19, 1996, 
you must be in compliance with the 1996 proposed standards upon 
startup. If today's final standards are more stringent than the 
proposed standards, you must be in compliance with the more stringent 
standards by September 30, 2002.

III. What Are the Requirements for the Notification of Intent to 
Comply?

    For the reader's convenience, we summarize here the Notice of 
Intent to Comply (NIC) requirements finalized in the ``fast-track'' 
rule of June 19, 1998. (See 63 FR at 33782.)
    The NIC requires you to prepare an implementation plan that 
identifies your intent to comply with the final rule and the basic 
means by which you intend to do so. That plan must be released to the 
public in a public forum and formally submitted to the Agency. The 
notice of intent certifies your intentions--either to comply or not to 
comply--and identifies milestone dates that measure your progress 
toward compliance with the final emission standards or your progress 
toward closure, if you choose not to comply. Prior to submitting the 
NIC to the regulatory Agency, you must provide notice of a public 
meeting and conduct an informal public meeting with your community to 
discuss the draft NIC and your plans for achieving compliance with the 
new standards.
    We have redesignated the existing NIC provisions to meld them into 
the appropriate sections of subpart EEE. We have also revised the 
regulatory language to include references to the new provisions 
promulgated today. See Part Six, Section IX of today's preamble.

IV. What Are the Requirements for Documentation of Compliance?

A. What Is the Purpose of the Documentation of Compliance?
    The purpose of the Documentation of Compliance 179 (DOC) 
is for you to certify by the compliance date that: (1) You have made a 
good faith effort to establish limits on the operating parameters 
specified in Sec. 63.1209 that you believe ensure compliance with the 
emissions standards; (2) required continuous monitoring systems are 
operational and meet specifications; and (3) you are in compliance with 
the other operating requirements. See Sec. 63.1211(d). This is 
necessary because all sources must be in compliance by the compliance 
date even though they are not required to demonstrate compliance, 
through performance testing, until 180 days after the compliance date. 
To fulfill the requirements of the DOC, you must place it in the 
operating record by the compliance date, September 30, 2002. (See 
compliance dates in Section II above.) Information that must be in the 
DOC includes all information necessary to determine your compliance 
status (e.g., operating parameter limits; functioning automatic waste 
feed cutoff system). All operating limits identified in the DOC are 
enforceable limits. However, if these limits are determined, after the 
initial comprehensive performance test, to have been inadequate to 
ensure compliance with the MACT standards, you will not be deemed to be 
out of compliance with the MACT emissions standards, if you complied 
with the DOC limits.180
---------------------------------------------------------------------------

    \179\ We renamed the proposed Precertification of Compliance as 
the Documentation of Compliance to avoid any confusion with the RCRA 
requirement of similar name.
    \180\ Once you determine that you failed to demonstrate 
compliance during the performance test, all monitoring data is 
subject to potential case-by-case use as credible evidence to show 
noncompliance following that determination. Therefore, you could 
potentially find yourself in noncompliance for the period which the 
DOC limits were in effect following that determination, but before 
submission of the NOC.
---------------------------------------------------------------------------

B. What Is the Rationale for the DOC?
    In the May 1997 NODA, we discussed the concept of the 
precertification of compliance (Pre-COC). The discussion required 
sources to precertify their compliance status on the compliance date by 
requiring them to submit a notification to the appropriate regulatory 
agency. This notification would detail the operating limits under which 
a source would operate during the period following the compliance date, 
but before submittal of the initial comprehensive performance test 
results in the Notification of Compliance.
    Commenters question this provision since the Pre-COC operating 
limits would be effective only for the 270 days following the 
compliance date. Other commenters support the Pre-COC requirements 
provided the process is focused, straightforward, and limited to the 
minimum operating parameters necessary to document compliance. 
Commenters also stress that the Agency needed to specify the 
requirements of the prenotification, using appropriate sections of 40 
CFR 266.103(b) and Section 63.9 when developing the specific regulatory 
requirements. In addition, commenters suggest that the Agency clarify 
the relationship between the Pre-COC and the title V permit, and 
indicate how or if the Pre-COC operating limits would be placed in the 
title V permit.
    Other commenters state that the rationale underlying the Pre-COC is 
faulty because sources would remain subject to the RCRA permit 
conditions until the NOC is submitted or until the title V permit is 
issued, which was our proposed approach to permitting at that time. 
Therefore, the Agency's concern that sources could be between 
regulatory regimes is not relevant. Commenters also state that Pre-COC 
requirements would be resource intensive and a needless exercise that 
diverted time and attention from preparing to come into compliance with 
MACT standards.
    The DOC requirements and process adopted today provide the Agency 
and public a sound measure of assurance

[[Page 52910]]

that, on the compliance date, combustion sources are operated within 
limits that should ensure compliance with the MACT standards and 
protection to human health and the environment. We agree that operating 
limits in the DOC will be in effect only for a short period of time and 
that affected sources will not be between regulatory regimes at any 
time. Given the relatively short period of time the DOC conditions will 
be in effect, however, we chose for the final rule not to specify 
whether the conditions need to be incorporated into a title V permit 
and do not require the permitting authority to do so. We provide 
flexibility for agencies implementing title V programs to determine the 
appropriate level of detail to include in the permit, thereby allowing 
them to minimize the potential need for permit revisions. In addition, 
we do not require that the DOC be submitted to the permitting 
authority, to avoid burdening the permitting agency with unnecessary 
paper work during the period that they are reviewing site-specific 
performance test plans. In today's rule, we better define the period 
during which the DOC applies by specifying that the DOC is superseded 
by the NOC upon the postmark date for submittal of the NOC. Once you 
mail the NOC, its contents become enforceable unless and until 
superseded by test results submitted within 270 days following 
subsequent performance testing. This approach provides clarity on when 
the NOC supersedes the DOC.
C. What Must Be in the DOC?
    You must complete your site-specific DOC and place it in your 
operating record by the compliance date. The DOC must contain all of 
the information necessary to determine your compliance status during 
periods of operation including all operating parameter limits. You must 
identify the DOC operating limits through the use of available data and 
information. If your unit requires modification or upgrades to achieve 
compliance with the emission standards, you can base this judgment on 
results of shakedown tests and/or manufacturers assertions or 
specifications. If your unit does not require modifications or upgrades 
to meet the emission standards of today's rule, you can develop the 
operating limits through analysis of previous performance tests or 
knowledge of the performance capabilities of your control equipment.
    Your limitations on operating parameters must be based on an 
engineering evaluation prepared under your direction or supervision in 
accordance with a system designed. This evaluation must ensure that 
qualified personnel properly gathered and evaluated the information and 
supporting documentation, and considering at a minimum the design, 
operation, and maintenance characteristics of the combustor and 
emissions control equipment, the types, quantities, and characteristics 
of feedstreams, and available emissions data.
    This requirement should not involve a significant effort because 
your decisions on whether to upgrade and modify your units will be 
based on the current performance of your control equipment and the 
performance capabilities of new equipment you purchase. We expect that, 
by the compliance date, you will have an adequate understanding of your 
unit's capabilities, given the three years to develop this expertise. 
Therefore, by the compliance date, you are expected to identify 
operating limits that are based on technical or engineering judgment 
that should ensure compliance with the emission standards.

V. What Are the Requirements for MACT Performance Testing?

A. What Are the Compliance Testing Requirements?
    Today's final rule requires two types of performance testing to 
demonstrate compliance with the MACT emission standards: Comprehensive 
and confirmatory performance testing. See Sec. 63.1207. The purpose of 
comprehensive performance testing is to demonstrate compliance and 
establish operating parameter limits. You must conduct your initial 
comprehensive performance tests by 180 days (i.e., approximately six 
months) after your compliance date. You must submit results within 90 
days (i.e., approximately 3 months) of completing your comprehensive 
performance test. If you fail a comprehensive performance test, you 
must stop burning hazardous waste until you can demonstrate compliance 
with today's MACT standards. Comprehensive performance testing must be 
repeated at least every five years, but may be required more frequently 
if you change operations or fail a confirmatory performance test.
    The purpose of confirmatory performance tests is to confirm 
compliance with the dioxin/furan emission standard during normal 
operations. You must conduct confirmatory performance tests midway 
between comprehensive performance tests. Confirmatory performance tests 
may be conducted under normal operating conditions. If you fail a 
confirmatory performance test, you must stop burning hazardous waste 
until you demonstrate compliance with the dioxin/furan standard by 
conducting a comprehensive performance test to establish revised 
operating parameter limits.
    The specific requirements and procedures for these two performance 
tests are discussed later in this section. In addition, this section 
discusses the interaction between the RCRA permitting process and the 
MACT performance test.
1. What Are the Testing and Notification of Compliance Schedules?
    Section 63.7 of the CAA regulations contains the general 
requirements for testing and notification of compliance. In today's 
rule, we adopt some Sec. 63.7 requirements without change and adopt 
others with modifications. As summarized earlier, you must commence 
your initial comprehensive performance test within 180 days after your 
compliance date, consistent with the general Sec. 63.7 requirements. 
You must complete testing within 60 days of commencement, unless a time 
extension is granted. This requirement is necessary because testing and 
notification of compliance deadlines are based on the date of 
commencement or completion of testing. Those deadlines could be 
meaningless if a source had unlimited time to complete testing. 
Although we propose to require testing to be completed within 30 days 
of commencement, commenters state that unforeseen events could occur 
(e.g., system breakdown causing extensive repairs; loss of samples from 
breakage of equipment or other causes requiring additional test runs) 
that could extend the testing period beyond normal time frames. We 
concur, and provide for a 60-day test period as well as a case-by-case 
time extension that may be granted by permit officials if warranted 
because of problems beyond our control.
    Additionally, you must submit comprehensive performance test 
results to the Administrator within 90 days of test completion, unless 
a time extension is granted. We are allowing an additional 30 days for 
result submittal beyond the Secs. 63.7(g) and 63.8(e)(5) 60-day 
deadlines because the dioxin/furan analyses required in today's rule 
may take this additional time to complete. We also are including a 
provision for a case-by-case time extension in the final rule because 
commenters express concern that the limited laboratory facilities 
nationwide may be taxed by the need to handle analyses simultaneously 
for many hazardous

[[Page 52911]]

waste combustors. The available analytical services may not be able to 
handle the workload, that could cause some sources to miss the proposed 
90-day deadline. We concur with commenters' concerns and have added a 
provision to allow permit officials to grant a case-by-case time 
extension, if warranted.
    Test results must be submitted as part of the notification of 
compliance (NOC) submitted to the Administrator under Secs. 63.1207(j) 
and 63.1210(d) documenting compliance with the emission standards and 
continuous monitoring system requirements, and identifying applicable 
operating parameter limits. These provisions are similar to 
Secs. 63.7(g) and 63.8(e)(5), except that the NOC must be postmarked by 
the 90th day following the completion of performance testing and the 
continuous monitoring system performance evaluation.
    Overall, the initial NOC must be postmarked within 270 days (i.e., 
approximately nine months) after your compliance date. You must 
initiate subsequent comprehensive performance tests within 60 months 
(i.e., five years) of initiating your initial comprehensive performance 
test. You must submit subsequent NOCs, containing test results, within 
90 days after the completion of subsequent tests.
    The rule allows you to initiate subsequent tests any time up to 30 
days after the deadline for the subsequent performance test. Thus, you 
can modify the combustor or add new emission control equipment at any 
time and conduct new performance testing to document compliance with 
the emission standards. In addition, this testing window allows you to 
plan to commence testing well in advance of the deadline to address 
unforseen events that could delay testing.181 This testing 
window applies to both comprehensive performance tests and confirmatory 
performance tests. For example, if the deadline for your second 
comprehensive performance test is January 10, 2008, you may commence 
the test at any time after completing the initial comprehensive 
performance test but not later than February 10, 2008. The deadline for 
subsequent comprehensive and confirmatory performance tests are based 
on the commencement date of the previous comprehensive performance 
test.
---------------------------------------------------------------------------

    \181\ We note that a case-by-case time extension for 
commencement of subsequent performance testing is also provided 
under Sec. 63.1207(i).
---------------------------------------------------------------------------

2. What Are the Procedures for Review and Approval of Test Plans and 
Requirements for Notification of Testing?
    In the April 1996 NPRM, we proposed in Sec. 63.7(b)(1) to require 
submittal of a ``notification of performance test'' to the 
Administrator 60 days prior to the planned test date. This notification 
included the site-specific test plan itself for review and approval by 
the Administrator (Sec. 63.8(e)(3)). In the May 1997 NODA, to ensure 
coordination of destruction removal efficiency (DRE) and MACT 
performance testing, we considered requiring you to submit the test 
plan one year rather than 60 days prior to the scheduled test date to 
allow the regulatory official additional time to consider DRE testing 
in context with MACT comprehensive performance testing. This one-year 
test review period would only have applied to sources required to 
perform a DRE test.
    In today's final rule, we maintain the requirement for you to 
submit the test plan one year prior to the scheduled test date, but 
apply that requirement to all sources, not just those performing a DRE 
test. After consideration of comments (described below), we determined 
that this one-year period is needed to provide regulatory officials 
sufficient time (i.e., nine months) to review and approve or notify you 
of intent to disapprove the plan. Nine months is needed for the review 
for all sources given the amount of technical information that would be 
included in the test plan, and would also allow time to assess whether 
a source is required to perform a DRE test (see Part IV, Section IV, 
for discussion of DRE testing requirements; see also 
Sec. 63.1206(b)(8)). During this nine-month period, the regulatory 
officials will review your test plan and determine if it is adequate to 
demonstrate compliance with the emission standards and establish 
operating requirements.
    After submittal of the test plan, review and approval or 
notification of intent to deny approval of the test plan will follow 
the requirements of Sec. 63.7(c)(3). That section provides procedures 
for you to provide additional information before final action on the 
plan. It also requires you to comply with the testing schedule even if 
permit officials have not approved your test plan. The only exception 
to this requirement is if you proposed to use alternative test methods 
to those specified in the rule. In that case, you may not conduct the 
performance test until the test plan is approved, and you have 60 days 
after approval to conduct the test.
    Several commenters suggest that it would be difficult for permit 
officials to review and approve test plans within the nine-month window 
given that many test plans may be submitted at about the same time. 
They cite experiences under RCRA trial burn plan approvals where permit 
officials have taken much longer than nine months to approve a plan, 
and have requested that the final rule allow for a longer review 
period. Commenters are concerned with the consequences of being 
required to conduct the performance test even though permit officials 
may not have had time to approve the test plan. They recite various 
concerns that permit officials may at a later date determine that the 
performance test was inadequate and require retesting. Commenters 
suggest that the rule establish the date for the initial comprehensive 
performance test as 60 days following approval of the test plan, 
whenever that may occur, thus extending the deadline for the 
performance test indefinitely from the current requirement of six 
months after the compliance date.
    We maintain that the nine-month review period is appropriate for 
several reasons. First, we are unwilling to build into the regulations 
an indefinite period for review. This would have the potential to delay 
implementation of the MACT emission standards without any clear and 
compelling reason to do so.
    Second, the RCRA experience with protracted approval schedules, 
sometimes over a decade ago, is not applicable or analogous to the MACT 
situation. Under the RCRA regulatory regime, particularly at the early 
stages, there were few incentives for either permit officials or owners 
or operators to expeditiously negotiate acceptable test plans. No 
statutory deadlines existed for a compliance date, and existing 
facilities operated under interim status (a type of grand fathering 
tantamount to a permit). This interim status scheme placed at least 
some controls on hazardous waste combustors during the permit 
application and trial burn test plan review periods. As a result, 
regulatory officials could take significant amounts of time to address 
what was then a new type of approval, that for trial burn testing to 
meet RCRA final permit standards.
    Under MACT, the situation today is quite different. In light of the 
statutory compliance date of 3 years and the existing regulatory 
framework, sources know as of today's final rule that they need to 
respond promptly and effectively to permit officials' concerns about 
the test plan because the performance test must be conducted

[[Page 52912]]

within six months after the compliance date whether or not the test 
plan is approved. And they have at least two years to prepare and 
submit these plans, and to work with regulatory officials even before 
doing so. For their part, permit officials recognize that they have the 
responsibility to review and approve the plan or notify the source of 
their intent to deny approval within the nine-month window given that 
the source must proceed with expensive testing on a fixed deadline 
whether or not the plan is approved. To the extent regulatory officials 
anticipate that many test plans will be submitted at about the same 
time, the agencies have at least two years to figure out ways to 
accommodate this scenario from a resource and a prioritization 
standpoint. If permit officials nevertheless fail to act within the 
nine-month review and approval period, a source could argue that this 
failure is tacit approval of the plan and that later ``second-
guessing'' is not allowable. This should be a very strong incentive for 
regulatory officials to act within the nine months, especially with a 
two-year lead time to avoid this type of situation
    In addition, the RCRA experience is not a particularly good 
harbinger of the future MACT test plan approval, as commenters suggest, 
because most sources will have already completed trial burn testing 
under RCRA. Thus, both the regulatory agencies and the facilities have 
been through one round of test plan submittal, review, and approval for 
their combustion units. Given that MACT testing is very similar to RCRA 
testing, approved RCRA test protocols can likely be modified as 
necessary to accommodate any changes required under the MACT rule. 
Although some of these changes may be significant, we expect that many 
will not be. For example, RCRA trial burn testing always included DRE 
testing. Under the MACT rule, DRE testing will not be required for most 
sources. And for sources where DRE testing is required under MACT, most 
will have already been through a RCRA approval of the DRE test 
protocol, which should substantially simplify the process under MACT.
    The third reason that we maintain the nine-month review and 
approval window is appropriate is that discussions with several states 
leads us to conclude that they are prepared to meet their obligations 
under this provision. This is a highly significant indicator that the 
nine-month review and approval period is a reasonable period of time, 
particularly since all permitting agencies have at least two years to 
plan for submittal of test plans from the existing facilities in their 
jurisdictions.
    In summary, sound reasons exist to expect that today's final rule 
provides sufficient time for the submittal, review, and approval of 
test plans. Furthermore, clear incentives exist for both owners and 
operators and permit officials to work together expeditiously to ensure 
that an approval or notice of intent to disapprove the test plan can be 
provided within the nine-months allotted.
    On a separate issue, we also retain, in today's final rule, the 60-
day time frame and requirements of Sec. 63.7(b)(1) for submittal of the 
notification of performance test. Additionally, the final rule 
continues to provide an opportunity for, but does not require, the 
regulatory agency to review and oversee testing.
3. What Is the Provision for Time Extensions for Subsequent Performance 
Tests?
    The Administrator may grant up to a one year time extension for any 
performance test subsequent to the initial comprehensive performance 
test. This enables you to consolidate MACT performance testing and any 
other emission testing required for issuance or reissuance of Federal/
State permits.182
---------------------------------------------------------------------------

    \182\ In addition, this provision also may assist you when 
unforseen events beyond your control (e.g., power outage, natural 
disaster) prevent you from meeting the testing deadline.
---------------------------------------------------------------------------

    At the time of proposal, we were concerned about how to allow 
coordination of MACT performance tests and RCRA trial burns. As 
discussed elsewhere, the RCRA trial burn is superseded by MACT 
performance testing. However, a one-year time extension may still be 
necessary for you to coordinate performance of a RCRA risk burn. In 
addition, commenters state that there may be additional reasons to 
grant extension requests (e.g. some TSCA-regulated hazardous waste 
combustors may be required to perform stack tests beyond those required 
by MACT). Furthermore, some sources may have to comply with state 
programs requiring RCRA trial burn testing. To address these 
situations, to promote coordinated testing, and to avoid unnecessary 
source costs, the final rule allows up to a one-year time extension for 
the performance test.
    When performance tests and other emission tests are consolidated, 
the deadline dates for subsequent comprehensive performance tests are 
adjusted correspondingly. For example, if the deadline for your 
confirmatory performance test is January 1 and your state-required 
trial burn is scheduled for September 1 of the same year, you can apply 
to adjust the deadline for the confirmatory performance test to 
September 1. If granted, this also would delay by a corresponding time 
period the deadline dates for subsequent comprehensive performance 
tests.
    The procedures for granting or denying a time extension for 
subsequent performance tests are the same as those found in 
Sec. 63.6(i), which allow the Administrator to grant sources up to one 
additional year to comply with standards.183 These are also 
the same procedures apply to a request for a time extension for the 
initial NOC.
---------------------------------------------------------------------------

    \183\ Note, however, that Sec. 63.6(i) applies to an entirely 
different situation: extension of time for initial compliance with 
the standards, not subsequent performance testing.
---------------------------------------------------------------------------

4. What Are the Provisions for Waiving Operating Parameter Limits 
During Subsequent Performance Tests?
    Operating parameter limits are automatically waived during 
subsequent comprehensive performance tests under an approved 
performance test plan. See Sec. 63.1207(h). This waiver applies only 
for the duration of the comprehensive performance test and during 
pretesting for an aggregate period up to 720 hours of operation. You 
are still required to be in compliance with MACT emissions standards at 
all times during these tests, however.
    In the April 1996 NPRM, we proposed to allow the burning of 
hazardous waste only under the operating limits established during the 
previous comprehensive performance test (to ensure compliance with 
emission standards not monitored with a continuous emissions monitoring 
system). Two types of waivers from this requirement would have been 
provided during subsequent comprehensive performance tests: (1) An 
automatic waiver to exceed current operating limits up to 5 percent; 
and (2) a waiver that the Administrator may grant if warranted to allow 
the source to exceed the current operating limits without restriction. 
We proposed an automatic waiver because, without the waiver, the 
operating limits would become more and more stringent with subsequent 
comprehensive performance tests. This is because sources would be 
required to operate within the more stringent conditions to ensure that 
they did not exceed a current operating limit. This would result in a 
shrinking operating envelope over time.
    A number of commenters question the comprehensive performance 
test's 5%

[[Page 52913]]

limit over existing permit conditions. Some commenters state that the 
EPA should not limit a facility's operating envelope from test to test 
based on operating conditions established during the previous test. The 
operator should be free to set any conditions for the comprehensive 
performance test, short of what the regulator deems to pose a short-
term environmental or health threat or inadequate to ensure compliance 
with an emission standard. Commenters also state that the requirement 
that the facility accept the more stringent of the existing 5% limit or 
the test result will inevitably result in the ratcheting down of limits 
over time. Since certain conditions have much greater variation than 5% 
over a limit, sufficient variability must be allowed so the operator 
can run a test under the conditions it wishes to use as the basis for 
worst case operation.
    We agree that a waiver is necessary to avoid ratcheting down the 
operating limits in subsequent tests. Further, in view of the natural 
variability in hazardous waste combustor operations, a 5% waiver may be 
insufficient. Because you are required to comply with the emission 
standards, there does not appear to be any reason to establish national 
restrictions on operations during subsequent performance tests. 
Therefore, the final rule allows a waiver from previously established 
operating parameter limits, as long as you comply with MACT emission 
standards and are operating under an approved comprehensive performance 
test plan. Operating parameter limits will be reset based on the new 
tests. Furthermore, the permitting authority will review and has the 
opportunity to disapprove any proposed test conditions which may result 
in an exceedance of an emission standard.
B. What Is the Purpose of Comprehensive Performance Testing?
    The purposes of the comprehensive performance test are to: (1) 
Demonstrate compliance with the continuous emissions monitoring 
systems-monitored emission standards for carbon monoxide and 
hydrocarbons; (2) conduct manual stack sampling to demonstrate 
compliance with the emission standards for pollutants that are not 
monitored with a continuous emissions monitoring system (e.g., dioxin/
furan, particulate matter, DRE, mercury, semivolatile metal, low 
volatile metal, hydrochloric acid/chlorine gas); (3) establish limits 
on the operating parameters required by Sec. 63.1209 (Monitoring 
Requirements) to ensure compliance is maintained with those emission 
standards for which a continuous emissions monitoring system is not 
used for compliance monitoring; and (4) demonstrate that performance of 
each continuous monitoring system is consistent with applicable 
requirements and the quality assurance plan. In general, the 
comprehensive performance test is similar in purpose to the RCRA trial 
burn and BIF interim status compliance test, but with relatively less 
Agency oversight and a higher degree of self-implementation, as 
discussed below.
    The basic framework for comprehensive performance testing is set 
forth in the existing general requirements of subpart A, part 63. 
Therefore, for convenience of the reader, we will review key elements 
of those regulations and highlight any modifications made specifically 
for hazardous waste combustors.
1. What Is the Rationale for the Five Year Testing Frequency?
    As discussed earlier, you must perform comprehensive performance 
testing every five years. We require periodic comprehensive performance 
testing because we are concerned that long-term stress to the critical 
components of a source (e.g., firing systems, emission control 
equipment) could adversely affect emissions.
    In the April 1996 NPRM, we proposed that large sources (i.e., those 
with a stack gas flow rate greater than 23,127 acfm) and sources that 
accept off-site wastes would be required to perform comprehensive 
performance testing every three years. We also proposed that small, on-
site sources perform comprehensive performance testing every five years 
unless the Administrator determined otherwise on a case-specific basis. 
Commenters suggest that the proposed three year testing frequency is 
too restrictive. They said that test plan approval time, bad weather, 
mechanical failure, and the testing itself combine to make the proposed 
test frequency too tight for tests of this magnitude.
    We agree that, due to the magnitude of the comprehensive 
performance test, a more appropriate testing schedule is required. 
Therefore, we adopt a comprehensive performance testing frequency of 
every five years for small and large sources. In addition, this 
comprehensive performance testing schedule should correspond to the 
renewal of the title V permit. More frequent comprehensive performance 
testing is required, however, if there is a change in design, 
operation, or maintenance that may adversely affect compliance. See 
Sec. 63.1206(b)(6).
2. What Operations Are Allowed During a Comprehensive Performance Test?
    Because day-to-day limits are established for operating parameters 
during the comprehensive performance test, we allow operation during 
the performance test as necessary provided the unit complies with the 
emission standards. Accordingly, you can spike feedstreams with metals 
or chlorine, for example, to ensure that the feedrate limits are 
sufficient to accommodate normal operations while allowing some 
flexibility to feed higher rates. See Part Four, Section I. B. above 
for further discussion of normal operations. We note that this differs 
from Sec. 63.7(e) which requires performance testing under ``normal'' 
operating conditions. See Sec. 63.1207(g).
    Most commenters agree that the comprehensive performance test 
should be conducted under extreme conditions at the edge of the 
operating envelope. Commenters point out that they needed to operate in 
this mode to establish operating parameter limits to cover all possible 
normal operating emissions values. Commenters also state that 
feedstreams may need to be spiked with metals or chlorine to ensure 
limits high enough to allow operational flexibility. We agree that 
these modes of operation are needed to establish operating parameter 
limits that cover all possible normal operating emissions 
values.184 There is precedent for this approach in current 
rules regulating hazardous waste combustors (e.g., the RCRA incinerator 
and BIF rules).
---------------------------------------------------------------------------

    \184\ Allowing sources to operate during MACT comprehensive 
performance testing under the worst-case conditions, as allowed 
during RCRA compliance testing, rather than under normal conditions 
as provided by Sec. 63.7(e) for other MACT sources, ensures that the 
emissions standards do not restrict hazardous waste combustors using 
MACT control to operations resulting in emissions that are lower 
than normal. Therefore, allowing performance testing on a worst-case 
basis provides that the MACT emission standards are achievable in 
practice by sources using MACT control.
---------------------------------------------------------------------------

    In addition, two or more modes of operation may be identified, for 
which separate performance tests must be conducted and separate limits 
on operating conditions must be established. If you identify two modes 
of operation for your source, you must note in the operating record 
which mode you are operating under at all times. For example, two modes 
of operation must be identified for a cement kiln that routes kiln off-
gas through the raw meal mill to help dry the raw meal. When the raw 
meal mill is not operating (perhaps 15% of the time), the kiln gas 
bypasses the raw meal mill. Emissions of particulate matter and other 
hazardous air

[[Page 52914]]

pollutants or surrogates may vary substantially depending on whether 
the kiln gas bypasses the raw meal mill.
    As discussed below for confirmatory testing, when conducting the 
comprehensive performance test, you also must operate under 
representative conditions for specified parameters that may affect 
dioxin/furan emissions. These conditions must ensure that emissions are 
representative of normal operating conditions. Also, when demonstrating 
compliance with the particulate matter, semivolatile metal, and low 
volatile metal emission standards, when using manual stack sampling, 
and when demonstrating compliance with the dioxin/furan and mercury 
emission standards using carbon injection or carbon bed, you must 
operate under representative conditions for the cleaning cycle of the 
particulate matter control device. This is because particulate matter 
emissions increase momentarily during cleaning cycles and can affect 
emissions of these pollutants.
3. What Is the Consequence of Failing a Comprehensive Performance Test?
    If you determine that you failed any emission standard during the 
performance test based on: (1) Continuous emissions monitoring systems 
recordings; (2) results of analysis of samples taken during manual 
stack sampling; or (3) results of the continuous emissions monitoring 
systems performance evaluation, you must immediately stop burning 
hazardous waste. However, if you conduct the comprehensive performance 
test under two or more modes of operation, and you meet the emission 
standards when operating under one or more modes of operation, you are 
allowed to continue burning under the mode of operation for which the 
standards were met.
    If you fail one or more emission standards during all modes of 
operation tested, you may burn hazardous waste only for a total of 720 
hours and only for the purposes of pretesting (i.e., informal testing 
to determine if the combustor can meet the standards operating under 
modified conditions) or comprehensive performance testing under 
modified conditions. The same standards apply for the retest as applied 
for the original test. These conditions apply when you fail the initial 
or subsequent comprehensive performance test.
    A number of commenters suggest that the 720 operating hours allowed 
after a failed performance test should be renewable, as they are under 
existing incinerator and BIF rules. We are persuaded by the commenters' 
rationale and will adopt this practice in today's rule. The final rule 
allows the 720 hours of operation following a failed performance test 
to be renewed as often as the Administrator deems reasonable. We note 
that hazardous waste combustors are currently subject to virtually 
these same requirements under RCRA rules.
    If you fail a comprehensive performance test, you must still submit 
a NOC as required indicating the failure. We want to ensure that the 
regulatory authorities are fully aware of a failure and the need for 
the facility to initiate retesting.
    We do not specifically address other consequences of failing the 
comprehensive performance test in the regulatory language. We will 
instead rely on the regulating agency's enforcement policy to govern 
the type of enforcement response at a facility that exceeds an emission 
standard, fails to ensure compliance with the standards, or fails to 
meet a compliance deadline.
C. What Is the Rationale for Confirmatory Performance Testing?
    Confirmatory performance testing for dioxin/furan is required 
midway between the cycle required for comprehensive performance testing 
to ensure continued compliance with the emission standard. We require 
such testing only for dioxin/furan given: (1) The health risks 
potentially posed by dioxin/furan emissions; (2) the lack of a 
continuous emissions monitoring system for dioxin/furan; (3) the lack 
of a material that directly and unambiguously relates to dioxin/furan 
emissions which could be monitored continuously by means of feedrate 
control (as opposed to, for example, metals feedrates, which directly 
relate to metals emissions); and (4) wear and tear on the equipment, 
including any emission control equipment, which over time could result 
in an increase in dioxin/furan emissions even though the source stays 
in compliance with applicable operating limits.
    Although emissions of dioxins/furans appear to be primarily a 
function of whether particulate matter is retained in post-combustion 
regions of the combustor (e.g., in an electrostatic precipitator or 
fabric filter, or on boiler tubes) in the temperature range that 
enhances dioxin/furan formation, the factors that affect dioxin/furan 
formation are imperfectly understood. Certain materials seem to inhibit 
formation while others seem to enhance formation. Some materials seem 
to be precursors (e.g., PCBs). Changes in the residence time of 
particulate matter in a control device may affect the degree of 
chlorination of dioxins/furans, and thus the toxicity equivalents of 
the dioxins/furans. Given these uncertainties, the health risks posed 
by dioxins/furans, and the relatively low cost of dioxin/furan testing, 
it appears prudent to require confirmatory testing to determine if 
changes in feedstocks or operations that are not limited by the MACT 
rule may have increased dioxin/furan emissions to levels exceeding the 
standard. We also note that confirmatory dioxin/furan testing is 
required for municipal waste combustors (60 FR at 65402 (December 19, 
1995)).
    Confirmatory testing differs from comprehensive testing, however, 
in that you are required to operate under normal, representative 
conditions during confirmatory testing. This will reduce the cost of 
the test, while providing the essential information, because you will 
not have to establish new operating limits based on the confirmatory 
test.
1. Do the Comprehensive Testing Requirements Apply to Confirmatory 
Testing?
    The following comprehensive performance testing requirements 
discussed above also apply to confirmatory testing: Agency oversight, 
notification of performance test, notification of compliance, time 
extensions, and failure to submit a timely notice of compliance. 
However, we modify some of the comprehensive test requirement for 
confirmatory tests, as discussed below.
2. What Is the Testing Frequency for Confirmatory Testing?
    You are required to conduct confirmatory performance testing 30 
months (i.e., 2.5 years) after the previous comprehensive performance 
test. The same two-month testing window, applicable for comprehensive 
tests, also applies to confirmatory tests.
    Several commenters state that the proposed schedule for 
confirmatory tests is too frequent. The April 1996 NPRM would have 
required large and off-site sources to conduct confirmatory performance 
testing 18 months after the previous comprehensive performance test. 
Small, on-site sources would have been required to conduct the testing 
30 months after the previous comprehensive performance test. One 
commenter suggests that the frequency should be at multiples of 12 
months to avoid seasonal weather problems in many locations. Other 
commenters state that EPA's justification for confirmatory tests is not 
supported by evidence

[[Page 52915]]

showing increased emissions due to equipment aging and that the 
performance of combustion practice parameters is already assured 
through continuous monitoring systems.
    We agree that due to the magnitude and expense of the test, a more 
appropriate testing schedule would be every 2.5 years, mid-way between 
the comprehensive performance test cycle. In addition, we agree that 
testing in certain locations at certain times of the year (e.g., 
northern states in the winter) can be undesirable. Although possible, 
it would add to the difficulty and expense of the testing. As 
previously discussed, sources can request a time extension to allow for 
a more appropriate testing season. However, the regulatory date for 
confirmatory testing remains midcycle to the comprehensive performance 
testing.
3. What Operations Are Allowed During Confirmatory Performance Testing?
    As proposed, you are required to operate under normal conditions 
during confirmatory performance testing. Normal operating conditions 
are defined as operations during which: (1) The continuous emissions 
monitoring systems that measure parameters that could relate to dioxin/
furan emissions--carbon monoxide or hydrocarbons--are recording 
emission levels within the range of the average value for each 
continuous emissions monitoring system (the sum of all one-minute 
averages, divided by the number of one minute averages) over the 
previous 12 months to the maximum allowed; (2) each operating parameter 
limit established to maintain compliance with the dioxin/furan emission 
standard (see discussion in Part Five, Section VI.D.1 below and 
Sec. 63.1209(k)) is held within the range of the average values over 
the previous 12 months and the maximum or minimums, as appropriate, 
that are allowed; (3) chlorine feedrates are set at normal or greater; 
and (4) when using carbon injection or carbon bed, the test is 
conducted under representative conditions for the cleaning cycle of the 
particulate matter control device. See Sec. 63.1207(g)(2).
    We define normal operating conditions in this manner because, 
otherwise, sources could elect to limit levels of the regulated dioxin/
furan operating parameters (e.g., hazardous waste feedrate, combustion 
chamber temperature, temperature at the inlet to the dry particulate 
matter control device) to ensure minimum emissions. Thus, without 
specifying what constitutes normal conditions, the confirmatory test 
could be meaningless. On the other hand, the definition of normal 
conditions is broad enough to allow adequate flexibility in operations 
during the test. The confirmatory test confirms that your under day-to-
day operations are meeting the dioxin/furan standard. Thus, the 
confirmatory test differs from the comprehensive performance test in 
which you may choose to extend to the edge of the operating envelope to 
establish operating parameters.
    The April 1996 NPRM would have required normal operating conditions 
for particulate matter continuous emissions monitoring systems. For the 
final rule, particulate matter levels are limited during confirmatory 
testing to ensure normal operations only when your source is equipped 
with carbon injection or carbon bed for dioxin/furan emissions control 
(see dioxin/furan operating limits discussion below).
    The April 1996 NPRM also would have required you to operate under 
representative conditions for types of organic compounds in the waste 
(e.g., aromatics, aliphatics, nitrogen content, halogen/carbon ratio, 
oxygen/carbon ratio) and volatility of wastes when demonstrating 
compliance with the dioxin/furan emission standard. Several commenters 
object to this requirement. We agree that restrictions on these organic 
compounds in the waste are redundant and not necessary to assure good 
combustion. In addition, the requirement would be impracticable because 
in most cases measured data would not be available on these parameters. 
Therefore, the final rule does not require ``representative'' wastes 
with regard to these organic compounds for confirmatory testing.
    It is prudent to require that chlorine be fed at normal levels or 
greater during the dioxin/furan confirmatory performance test. Although 
most studies show poor statistical correlation between dioxin/furan 
emissions and chlorine feedrate, some practical considerations are 
important. Chlorinated dioxin/furan obviously contain chlorine and some 
level of chlorine is necessary for its formation. During the 
confirmatory testing for dioxin/furan, we want you to operate your 
combustor under normal conditions relative to factors that can affect 
emissions of dioxin/furan. Therefore, you must feed chlorine at normal 
or greater levels given the potential for chlorine feedrates to affect 
dioxin/furan emissions. For the confirmatory performance test, normal 
is defined as the average chlorine fed over the previous 12 months. If 
you have established a maximum chlorine value for metals or total 
chlorine compliance in your previous comprehensive performance test, 
then that value can be used in the confirmatory test.
    Several commenters suggest that when defining normal operation, a 
provision should be made to exclude inappropriate data, such as those 
occurring during instrument malfunction, at unit down time, or during 
instrument zero/calibration adjustment. The April 1996 NPRM did not 
allow for any data to be excluded. To define ``normal'' operation, we 
agree it is reasonable to exclude inappropriate data. For the final 
rule, calibration data, malfunction data, and data obtained when not 
burning hazardous waste do not fall into the definition of ``normal'' 
operation.
4. What Are the Consequences of Failing a Confirmatory Performance 
Test?
    If you determine that you failed the dioxin/furan emission standard 
based on results of analysis of samples taken during manual stack 
sampling, you must immediately stop burning hazardous waste. You must 
then modify the design or operation of the unit, conduct a new 
comprehensive performance test to demonstrate compliance with the 
dioxin/furan emission standard (and other standards if the changes 
could adversely affect compliance with those standards), and establish 
new operating parameter limits. Further, prior to submitting a NOC 
based on the new comprehensive performance test, you can burn hazardous 
waste only for a total of 720 hours (renewable based on the discretion 
of the Administrator) and only for purposes of pretesting or 
comprehensive performance testing. These conditions apply when you fail 
the initial or any periodic confirmatory performance test.
    However, if you conduct the comprehensive performance test under 
two or more modes of operation, and meet the dioxin/furan emission 
standards during confirmatory testing when operating under one or more 
modes of operation, you may continue burning under the modes of 
operation for which you meet the standards.
    Other than stopping burning of hazardous waste, we do not 
specifically address the consequences of failing the confirmatory 
performance test in the regulatory language but will instead rely on 
the regulating agency's enforcement policy to govern the type of 
enforcement response at a facility that exceeds an emission standard, 
fails to ensure compliance with the standards, or fails to meet a 
compliance deadline. This approach is consistent with the way

[[Page 52916]]

other MACT standards are implemented.
    Some commenters suggest that the requirement to stop burning waste 
after a failed confirmatory test is overly harsh. They suggest that 
temporarily restricted burning should be allowed, conservative enough 
to insure compliance, while a permanent solution is developed. We 
continue to believe that a source should stop burning hazardous waste 
until it reestablishes operating parameter limits that ensure 
compliance with the dioxin/furan emission standard. We note that 
hazardous waste combustors are currently subject to virtually these 
same requirements under RCRA rules.
D. What Is the Relationship Between the Risk Burn and Comprehensive 
Performance Test?
1. Is Coordinated Testing Allowed?
    Traditionally, a RCRA trial burn serves three primary functions: 
(1) Demonstration of compliance with performance standards such as 
destruction and removal efficiency; (2) determination of operating 
conditions that assure the hazardous waste combustor can meet 
applicable performance standards; and (3) collection of emissions data 
for incorporation into a SSRA that, subsequently, is used to establish 
risk-based permit conditions where necessary.185 Today's 
rulemaking transfers the first two functions of a RCRA trial burn from 
the RCRA program to the CAA program. The responsibility for collecting 
emissions data needed to perform a SSRA is not transferred because 
SSRAs are exclusively a RCRA matter.
---------------------------------------------------------------------------

    \185\ Under 40 CFR 270.10(k), which is the RCRA Part B 
information requirement that supports implementation of the RCRA 
omnibus permitting authority, a regulatory authority may require a 
RCRA permittee or an applicant to submit information to establish 
permit conditions as necessary to protect human health and the 
environment. Under this authority, risk burns and SSRAs may be 
required.
---------------------------------------------------------------------------

    Generally speaking, the type of emissions data needed to conduct a 
SSRA includes concentration and gas flow rate data for dioxin/furans, 
nondioxin/furan organics, metals, hydrogen chloride, and chlorine gas. 
Additionally, particle-size distribution data are normally needed for 
the air modeling component of the SSRA. We have recently published 
guidance on risk burns and the data to be collected. See USEPA, ``Human 
Health Risk Assessment Protocol for Hazardous Waste Combustion 
Facilities'' External Peer Review Draft, EPA-530-D-98-001A, B & C and 
USEPA, ``Guidance on Collection of Emissions Data to Support Site-
Specific Risk Assessments at Hazardous Waste Combustion Facilities,'' 
EPA 530-D-98-002, August 1998.
    A large number of hazardous waste combustors subject to today's 
rule will have completed a RCRA trial burn and SSRA emissions testing 
prior to the date of the MACT comprehensive performance test. There may 
exist, however, some facilities for which this is not the case. For 
these facilities, the Agency proposed, in both the April 1996 NPRM and 
the May 1997 NODA, an option of coordinating SSRA emissions data 
collection with MACT performance testing. Facilities choosing to 
perform coordinated testing would be expected to factor SSRA data 
collection requirements into the MACT performance test plan. Commenters 
support this approach, emphasizing that coordinated testing would 
conserve the resources of both the regulatory authority and regulated 
source. The Agency agrees with the commenters and continues to support 
coordinated testing. There is no need, however, for today's final rule 
to include regulatory language for coordinated testing since it is 
simply matter of submitting and implementing a test plan which 
accomplishes the objectives of both a risk burn and MACT performance 
test.
    Coordinated testing may not be possible for all hazardous waste 
combustors subject to today's MACT standards. Some sources may not be 
able to test under one set of conditions that addresses all data needs 
for both MACT implementation and SSRAs. SSRA emissions testing 
traditionally is performed under worst-case conditions, but may be 
obtained under normal testing conditions when necessary.186 
As noted in the April 1996 NPRM, as well as in this preamble, we 
generally anticipate sources will conduct MACT performance testing 
under conditions that are at the edge of the operating envelope or the 
worst-case to ensure operating flexibility. Regardless of which test 
conditions are used to collect SSRA emissions data, under the 
coordinated testing scenario, those conditions should be consistent 
with the MACT performance test to the extent possible.
---------------------------------------------------------------------------

    \186\ Criteria for determining the circumstances under which 
SSRA emissions data should be collected using normal versus worst-
case testing conditions are provided in EPA's Guidance on Collection 
of Emissions Data to Support Site-Specific Risk Assessments at 
Hazardous Waste Combustion Facilities (EPA 530-D-98-002, August 
1998).
---------------------------------------------------------------------------

    Similarly, a source may experience difficulty integrating MACT 
performance testing with SSRA emissions testing due to conflicting 
goals in establishing enforceable operating parameters, i.e., a 
parameter cannot be maximized for purposes of the SSRA data collection 
while at the same time be properly maximized or minimized for purposes 
of performance testing. It is additionally important to ensure that the 
feed material used during the performance testing is appropriate for 
SSRA emissions testing. When collecting emissions data for a SSRA, 
testing with actual worst-case waste is preferred to ensure that the 
testing material is representative of the toxic, persistence and 
bioaccumulative characteristics of the waste that ultimately will be 
burned. However, even if multiple tests need to be performed to 
accomplish all of the objectives, it is still advantageous to conduct 
these tests in the same general time frame to minimize mobilization and 
sampling costs.
    The timing of the required tests may cause difficulty for some 
sources wishing to use coordinated testing. As we discussed in the May 
1997 NODA, if the timing of the SSRA data collection does not coincide 
with the MACT performance test requirement, the performance test should 
not be unduly delayed. Commenters agree with this approach.
2. What Is Required for Risk Burn Testing?
    We expect that sources for which coordinated testing is not 
possible will need to obtain SSRA emissions data through a separate 
risk burn. Similar to a traditional RCRA trial burn, risk burn testing 
should be conducted pursuant to a test plan that is reviewed and 
approved by the RCRA permitting authority. 40 CFR 270.10(k) provides 
that the permitting authority may require the submittal of information 
to establish permit conditions to ensure a facility's operations will 
be protective of human health and the environment. This regulatory 
requirement provides for the collection of emissions data, as 
appropriate, for incorporation into a SSRA as well as for the 
performance of the SSRA itself. We clarify in amendments to 
Secs. 270.19, 270.22, 270.62 and 270.66 that the Director may apply 
provisions from those sections, on a case-by-case basis, to establish a 
regulatory framework for conducting the risk burn under Sec. 270.10(k) 
and imposing risk-based conditions under Sec. 270.32(b)(2) (omnibus 
provisions). This clarifying language is intended to prevent any 
confusion from other language added to Secs. 270.19, 270.22, 270.62 and 
270.66 today stating that

[[Page 52917]]

these provisions otherwise no longer apply once a source has 
demonstrated compliance with the MACT standards and limitations of 40 
CFR part 63, subpart EEE. (See Part Five, Section XI.B.3 for further 
discussion.) Facilities and regulatory authorities may consult existing 
EPA guidance documents for information regarding the elements of risk 
burn testing.187
---------------------------------------------------------------------------

    \187\ USEPA. ``Human Health Risk Assessment Protocol for 
Hazardous Waste Combustion Facilities'' External Peer Review Draft. 
EPA-530-D-98-001A,B&C. Date.; USEPA, ``Guidance on Collection of 
Emissions Data to Support Site-Specific Risk Assessments at 
Hazardous Waste Combustion Facilities'' EPA 530-D-98-002. August 
1998.
---------------------------------------------------------------------------

E. What Is a Change in Design, Operation, and Maintenance? (See 
Sec. 63.1206(b)(6).)
    The April 1996 NPRM noted that sources may change their design, 
operation, or maintenance practices in a manner that may adversely 
affect their ability to comply with the emission standards. These 
sources would be required to conduct a new comprehensive performance 
test to demonstrate compliance with the affected emission standards and 
would be required to re-establish operating limits on the affected 
parameters specified in Sec. 63.1209. (See 61 at FR 17518.) The 
proposal stated that until a complete and accurate revised NOC is 
submitted to the Administrator, sources would be permitted to burn 
hazardous waste following such changes for time a period not to exceed 
720 hours and only for the purposes of pretesting or comprehensive 
performance testing. The approach in the April 1996 NPRM remains 
appropriate, and we are adopting it in today's final rule with minor 
modifications.
    For changes made after submittal of your NOC that may adversely 
affect compliance with any emission standard, as defined later in this 
section, today's rule requires you to notify the Administrator at least 
60 days prior to the change unless you document circumstances that 
dictate that such prior notice is not reasonably feasible. The 
notification must include a description of the changes and which 
emission standards may be affected. The notification must also include 
a comprehensive performance test schedule and test plan that will 
document compliance with the affected emission standard(s). You must 
conduct a comprehensive performance test to document compliance with 
the affected emission standard(s) and establish operating parameter 
limits as required and submit a revised NOC to the Administrator. You 
also must not burn hazardous waste for more than a total of 720 hours 
after the change and prior to submitting your NOC, and you must burn 
hazardous waste during this time period only for the purposes of 
pretesting or comprehensive performance testing.
    Some commenters are uncomfortable with the proposed regulatory 
language, stating that it was too generic and that the Agency could 
require a comprehensive performance test even after minor changes in 
maintenance practices. One commenter suggests that EPA incorporate a 
list of changes significant enough to affect compliance, similar to 
what is currently done in the RCRA permit modification classification 
scheme in Appendix I of Sec. 270.42.
    We intentionally proposed an approach that provides some degree of 
flexibility to permit authorities. Individual facilities will need to 
consult with these permit authorities who will make the decision on the 
site-specific facts. We do not intend to require a comprehensive 
performance test after minor modifications to system design, or after 
implementing minor changes to operating or maintenance practices. We 
considered incorporating sections of Appendix I of Sec. 270.42 to 
further clarify when comprehensive performance tests would be 
required.188 However, it is impossible to envision all 
scenarios in which changes in design, operation, or maintenance 
practices may or may not trigger the requirement of a complete, or even 
partial, comprehensive performance test. Discussion of specific 
scenarios is more suitable in an Agency guidance document as opposed to 
regulatory provisions, and implemented on a site-specific basis. Thus, 
the April 1996 NPRM set out the regulatory approach as well as can be 
done, and we are adopting it today with minor modifications.
---------------------------------------------------------------------------

    \188\ One approach would be to require performance tests for 
modifications covered by the class 2 and class 3 permit 
modifications associated with combustion source design and operating 
parameter changes.
---------------------------------------------------------------------------

    In the April 1996 NPRM, we did not address what must be done when 
you change design, operation, or maintenance practices during the time 
period between the compliance date and when you submit your NOC. If you 
make a change during this time period, today's rule requires you to 
revise your DOC, which is maintained on-site, to incorporate any 
revised limits necessary to comply with the standards. For purposes of 
this provision, today's rule defines ``change'' as any change in 
reported design, operation, or maintenance practices you previously 
documented to the Administrator in your comprehensive performance test 
plan, NOC, DOC, or startup, shutdown, and malfunction plan.
    Commenters point out that the proposal did not discuss 
recordkeeping requirements necessary for the Administrator to determine 
if you are adequately concluding that changes in design, operation, or 
maintenance practices do not trigger a comprehensive performance test 
requirement 189. As a result, today's rule requires you to 
document in your operating record whenever you make a change (as 
defined above) in design, operation, or maintenance practices, 
regardless of whether the change may adversely affect your ability to 
comply with the emission standards. See Sec. 63.1206(b)(6)(ii). You are 
also required to maintain on site an updated comprehensive performance 
test plan, NOC, and startup, shutdown, and malfunction plan that 
reflect these changes. See Sec. 63.1211(c).
---------------------------------------------------------------------------

    \189\ We cannot determine if a source has accurately concluded 
that a change does not adversely affect its ability to comply with 
the emission standards if we are never aware that changes were made 
to the source.
---------------------------------------------------------------------------

F. What Are the Data In Lieu Allowances?
    You are allowed to submit data from previous emissions tests in 
lieu of performing a MACT performance test to set operating limits. See 
Sec. 63.1207(c)(2). To use previous emissions test data, the data must 
have been collected less than 5 years before the date you intend to 
submit your notification of compliance. The data must also have been 
collected as part of a test that was for the purpose of demonstrating 
compliance with RCRA or CAA requirements. Additionally, you must submit 
your request to use previous test data in your comprehensive 
performance test plan which is submitted 1 year in advance of the MACT 
performance test. Finally, you must schedule your subsequent MACT 
performance test and MACT confirmatory test 5 years and 2.5 years 
respectively following the date the emissions test data your submitting 
was collected.
    We developed this allowance in response to comments that suggested 
we should allow previous RCRA testing to be used in lieu of performing 
a new MACT performance test if the data could be used to demonstrate 
compliance and establish operating limits to ensure compliance with the 
MACT emissions standards. Commenters reasoned, and we agreed, that such 
an allowance was reasonable and necessary for those sources that

[[Page 52918]]

must perform emissions tests to satisfy other state or federal 
requirements. As we developed this allowance, we decided that it is 
necessary to limit the age of the data and specify the date of the 
following performance test because we need to be consistent with the 
MACT performance test requirements with respect to testing frequency. 
We can further justify the time and testing limitations of the data in 
lieu of allowance by acknowledging that we don't want some sources 
gaining an advantage over others by extending the date between 
performance tests. However, we also weighed the fact that some sources 
may be required to perform RCRA testing fairly close to the compliance 
date or promulgation date of today's rule and we didn't want to 
penalize them by forcing them to perform a new performance test before 
five years had elapsed since their previous test. So we settled on an 
approach that allows the use of previous emissions test data and 
effectively sets the same testing frequency as is applied to test data 
collected via a MACT performance test following the compliance date. 
This approach doesn't penalize or favor any source over another and it 
allows each source to take advantage of this provision when it makes 
sense. For instance, a source may be granted approval to use data from 
a RCRA trial burn performed 1 year before today's date, thus not 
requiring the source to perform a comprehensive performance test 270 
days following the compliance date. Instead, the source must schedule 
its next MACT performance test five years after the date the test was 
performed. However, the source must perform a confirmatory test 270 
days following the compliance date because the test schedule for the 
confirmatory test is also linked to the date of the performance test. 
So in this situation the source must determine if its better to run the 
comprehensive performance test on a normal schedule after the 
compliance date or delay the comprehensive test and perform a 
confirmatory test instead.

VI. What Is the Notification of Compliance?

A. What Are the Requirements for the Notification of Compliance?
    You must submit to the Administrator the results of the 
comprehensive performance test in a notification of compliance (NOC) no 
later than three months after the conclusion of the performance test. 
You must submit the initial NOC later than nine months following the 
compliance date.
B. What Is Required in the NOC?
    You must include the following information in the NOC:

--Results of the comprehensive performance test, continuous monitoring 
system performance evaluation, and any other monitoring procedures or 
methods that you conducted;
--Test methods used to determine the emission concentrations and 
feedstream concentrations, as well as a description of any other 
monitoring procedures or methods that you conducted;
--Limits for the operating parameters;
--Procedures used to identify the operating parameter limits specified 
in Sec. 63.1209;
--Other information documenting compliance with the operating 
requirements, including but not limited to automatic waste feed cutoff 
system operability and operator training;
--A description of the air pollution control equipment and the 
associated hazardous air pollutant that each device is designed to 
control; and
--A statement from you or your company's responsible official that the 
facility is in compliance with the standards and requirements of this 
rule.
C. What Are the Consequences of Not Submitting a NOC?
    The normal CAA enforcement procedures apply if you fail to submit a 
timely notification of compliance. We do not adopt our proposed 
approach that would have required you to immediately stop burning 
hazardous waste if you failed to submit a timely NOC.
    We proposed regulatory language stating that failure to submit a 
notification of compliance by the required date would result in the 
source being required to immediately stop burning hazardous waste. This 
proposal was similar to requirements applied to BIFs certifying 
compliance under RCRA. Under the proposal, if you wanted to burn 
hazardous waste in the future, you would be required to comply with the 
standards and permit requirements for new MACT and RCRA sources.
    In the 1997 NODA, however, we proposed to rely on the regulating 
agency's policy regarding enforcement response to govern the type of 
enforcement response at a facility that fails to submit a notification 
of compliance. Based on NODA comments and review of this enforcement 
process, we are not including in the final rule regulatory language 
addressing the consequences of failure to submit a timely or complete 
NOC. Instead, we rely on the regulating agency's policy regarding 
enforcement response to govern the type of enforcement response at a 
facility that fails to meet a compliance deadline. This approach is 
more practical to implementing today's MACT standards and is more 
consistent with the way other MACT standards are implemented.
D. What Are the Consequences of an Incomplete Notification of 
Compliance?
    In response to our April 1996 NPRM, commenters state that we were 
unclear as to the consequences of an incomplete NOC. Furthermore, 
commenters state that it was important that we specify what is needed 
and the consequences if an NOC is incomplete or more information is 
needed. Additionally, commenters recommend that if the NOC contains 
emission information, the certification statement, and a signature, we 
should judge the NOC to be administratively complete and an acceptable 
submission. In addition, commenters suggest that if the regulatory 
official reviewing the NOC determines that additional information is 
required, the source should be given ample time to submit that 
information.
    Our enforcement approach to incomplete submissions, under RCRA or 
the CAA, is generally determined on a site-specific basis. We will not 
attempt to foresee and develop enforcement responses to all the 
possible levels of incompleteness for the NOC. This is beyond the scope 
of our national rulemaking. Furthermore, defining what constitutes an 
incomplete submission requires us to specifically prescribe a complete 
submission, which is not possible for all situations or all source 
designs. Some sources may require more detail than others in defining 
the parameters necessary to determine compliance on a continuous basis. 
Therefore, we instead define the minimum information necessary in the 
submission and allow the implementing agency to determine if more 
information is necessary in a facility's site-specific NOC.
    In response to comments advocating that facilities be given ample 
time to submit additional information required by the regulatory 
official, we prefer to allow the implementing agency to determine the 
time periods that will be granted to submit additional information 
because some information requests may require widely varying degrees of 
time and effort to develop. Many potential problems associated with 
incomplete submissions can be prevented through interaction between

[[Page 52919]]

the source and the regulatory agency during the test plan review and 
approval process. We do not want our rules to act as disincentive to 
those discussions by providing a complete shield, regardless of the 
severity of the omission.
E. Is There a Finding of Compliance?
    We adopt the requirement we proposed for the regulatory agencies to 
make a finding of compliance based on performance test results (see 
Sec. 63.1206(b)(3)). This provision specifies that the regulatory 
agency must determine whether an affected source is in compliance with 
the emissions standards and other requirements of subpart EEE, as 
provided by the general provisions governing findings of compliance in 
Sec. 63.6(f)(3). Thus, the regulatory agency is obligated to make this 
finding upon obtaining all the compliance information required by the 
standards, including the written reports of performance test results, 
monitoring results, and other applicable information. This includes, 
but may not be limited to, the information submitted by the source in 
its NOC.

VII. What Are the Monitoring Requirements?

    In this section, we discuss the following topics: (1) The 
compliance monitoring hierarchy that places a preference on compliance 
with a CEMS; (2) how limits on operating parameters are established 
from comprehensive performance test data; (3) status and use of CEMS 
other than carbon monoxide, hydrocarbon, and oxygen CEMS; and (4) final 
compliance monitoring requirements for each emission standard.
A. What Is the Compliance Monitoring Hierarchy?
    We proposed the following three-tiered compliance monitoring 
hierarchy in descending order of preference to ensure compliance with 
the emission standards: (1) Use of a continuous emission monitoring 
system (CEMS) for a hazardous air pollutant; (2) absent a CEMS for that 
hazardous air pollutant, use of a CEMS for a surrogate of that 
hazardous air pollutant and, when necessary, setting limits on 
operating parameters to account for the limitations of using 
surrogates; and (3) lacking a CEMS for either, requiring periodic 
emissions testing and site-specific limits on operating parameters. 
Accordingly, we proposed to require the use of carbon monoxide, 
hydrocarbon, oxygen, particulate matter, and total mercury CEMS. We 
also proposed performance specifications for multimetal, hydrochloric 
acid, and chlorine gas CEMS to give sources the option of using a CEMS 
for compliance with the semivolatile and low volatile metal emissions 
standards, and the hydrochloric acid/chlorine gas emission standard.
    Commenters question the availability and reliability of CEMS other 
than those for carbon monoxide, hydrocarbon, and oxygen. We concur with 
some of the commenters' concerns and are not requiring use of a total 
mercury CEMS in the final rule or specifying the installation deadline 
and performance specifications for particulate matter CEMS. In 
addition, we have not promulgated performance specifications for these 
CEMS or multimetal, hydrochloric acid, and chlorine gas CEMS. We 
nonetheless continue to encourage sources to evaluate the feasibility 
of using these CEMS to determine the performance specifications, 
correlation acceptance criteria, and detector availability that can be 
achieved. Sources may request approval from permitting officials under 
Sec. 63.8(f) to use CEMS to document compliance with the emission 
standards in lieu of periodic performance testing and compliance with 
limits on operating parameters. See discussion in Section VII.C below 
on these issues.
B. How Are Comprehensive Performance Test Data Used To Establish 
Operating Limits?
    In this section, we discuss: (1) The definitions of terms related 
to monitoring and averaging periods; (2) the rationale for the 
averaging periods for operating parameter limits, (3) how comprehensive 
performance test data are averaged to calculate operating parameter 
limits; (4) how the various types of operating parameters are 
monitored/established; (5) how nondetect performance test feedstream 
data are handled; and (6) how rolling averages are calculated 
initially, upon intermittent operations, and when the hazardous waste 
feed is cut off.
1. What Are the Definitions of Terms Related to Monitoring and 
Averaging Periods?
    In the April 1996 NPRM, we proposed definitions for several terms 
that relate to monitoring and averaging periods. For the reasons 
discussed below, we conclude that the proposed definitions are 
appropriate and are adopting them in today's rule. We also finalize 
definitions for ``average run average'' and ``average highest or lowest 
rolling average'' which were not proposed. We conclude these new 
definitions are necessary to clarify the meaning and intent of 
regulatory provisions associated with the monitoring requirements that 
are discussed in Part 5, Section VII.D. of this preamble.
    We promulgate the following definitions in today's rule (see 
Sec. 63.1201).
    ``Average highest or lowest rolling average'' means the average of 
each run's highest or lowest rolling average run within the test 
condition for the applicable averaging period.
    ``Average run average'' means the average of each run's average of 
all associated one minute values.
    ``Continuous monitor'' means a device that: (1) Continuously 
samples a regulated parameter without interruption; (2) evaluates the 
detector response at least once every 15 seconds; and (3) computes and 
records the average value at least every 60 seconds, except during 
allowable periods of calibration and as defined otherwise by the CEMS 
Performance Specifications in appendix B of part 60.
    ``Feedrate operating limits'' means limits on the feedrate of 
materials (e.g., metals, chlorine) to the combustor that are 
established based on comprehensive performance testing. The limits are 
established and monitored by knowing the concentration of the limited 
material (e.g., chlorine) in each feedstream and the flow rate of each 
feedstream.
    ``Feedstream'' means any material fed into a hazardous waste 
combustor, including, but not limited to, any pumpable or nonpumpable 
solid, liquid, or gas.
    ``Flowrate'' means the rate at which a feedstream is fed into a 
hazardous waste combustor.
    ``Instantaneous monitoring'' means continuously sampling, 
detecting, and recording the regulated parameter without use of an 
averaging period.
    ``One-minute average'' means the average of detector responses 
calculated at least every 60 seconds from responses obtained at least 
each 15 seconds.
    ``Rolling average'' means the average of all one-minute averages 
over the averaging period.
    One commenter opposes the requirement to take instrument readings 
every 15 seconds. This commenter contends that such an approach is 
simply impractical, unnecessary, and imposes a harsh burden upon 
members of the regulated community. Another commenter maintains that 
the CEMS Data Acquisition System should be capable of sampling the 
analyzer outputs at least every 15 seconds. With today's processing 
power and speed, the commenter states that this can easily be achieved. 
We agree with the second commenter and are requiring instrument

[[Page 52920]]

readings at least every 15 seconds because this is currently required 
in the Boilers and Industrial Furnace rulemaking. (See 
Sec. 266.102(e)(6))
    Another commenter states that the Agency's definition of 
``instantaneous monitoring'' of combustion chamber pressure to control 
combustion system leaks is not clear.190 The commenter 
states that, although an instantaneous limit cannot be exceeded at any 
time, continuous monitoring systems are required to detect parameter 
values only once every 15 seconds. We note that the final rule requires 
instantaneous monitoring only for the combustion chamber pressure limit 
to control combustion system leaks. The rule requires an automatic 
waste feed cutoff if the combustion chamber pressure at any time (i.e., 
instantaneously) exceeds ambient pressure (see Sec. 63.1209(p)). The 
definition of a continuous monitoring system is that it must record 
instrument readings at least every 15 seconds. For instantaneous 
monitoring of pressure, the detector must clearly record a response 
more frequently than every 15 seconds.191 It must detect and 
record pressure constantly without interruption and without any 
averaging period.
---------------------------------------------------------------------------

    \190\ ``Combustion system leaks'' is the term used in today's 
rule to refer to leaks that are called fugitive emissions under 
current RCRA regulations. We use the term combustion system leaks to 
refer to those emissions because the term fugitive emissions has 
other meanings under part 63.
    \191\ Typical pressure transducers in use today are capable of 
responding to pressure changes once every fifty milliseconds. See 
USEPA, ``Final Technical Support Document for Hazardous Waste 
Combustor MACT Standards, Volume IV: Compliance with the Hazardous 
Waste Combustor Standard,'' July 1999.
---------------------------------------------------------------------------

2. What Is the Rationale for the Averaging Periods for the Operating 
Parameter Limits?
    The final rule establishes the following averaging periods: (1) No 
averaging period (i.e., instantaneous monitoring) for maximum 
combustion chamber pressure to control combustion system leaks; (2) 12-
hour rolling averages for maximum feedrate of mercury, semivolatile 
metals, low volatile metals, chlorine, and ash (for incinerators); and, 
(3) one-hour averaging periods for all other operating parameters. As 
discussed later in this section, we conclude that the proposed ten-
minute averaging periods are not necessary, on a national basis, to 
better ensure compliance with the emission standards at hazardous waste 
combustors, and have not adopted these averaging periods in this 
rulemaking.
    a. When Is an Instantaneous Limit Used? An instantaneous limit is 
required only for maximum combustion chamber pressure to control 
combustion system leaks. This is because any perturbation above the 
limit may result in uncontrolled emissions exceeding the standards.
    b. When Is an Hourly Rolling Average Limit Used? An hourly rolling 
average limit is required for all parameters that are based on 
operating data from the comprehensive performance test, except 
combustion chamber pressure and feedrate limits. Hourly rolling 
averages are required for these parameters rather than averaging 
periods based on the duration of the performance test because we are 
concerned that there may be a nonlinear relationship between operating 
parameter levels and emission levels of hazardous air pollutants.
    c. Why Has the Agency Decided Not to Adopt Ten-Minute Averaging 
Periods? Dual ten-minute and hourly rolling averages were proposed for 
most parameters for which limits are based on the comprehensive 
performance test. See 61 FR at 17417. We proposed ten-minute rolling 
averages in addition to hourly rolling averages for these parameters 
because short term excursions of the parameter can result in a 
disproportionately large excursion of the hazardous air pollutant being 
controlled.
    Commenters claim that the Agency's concerns with emission 
excursions due to short term perturbations of these operating 
parameters were not supported with data and are therefore unjustified, 
and claim that averaging periods shorter than those required in the 
existing BIF regulations would provide no environmental benefit.
    We acknowledge that the Agency does not have extensive short-term 
emission data that show operating parameter excursions can result in 
disproportionately large excursions of hazardous air pollutants being 
emitted. These short-term data cannot be obtained without the use of 
continuous emission monitors that measure dioxin/furans, metals, and 
chlorine on a real-time basis. Such monitors, for the most part, are 
not currently used for compliance purposes at hazardous waste 
combustors. However, known relationships between operating parameters 
and hazardous air pollutant emissions indicate that a nonlinear 
relationship exists between operating parameter levels and emissions. 
This nonlinear relationship can result in source emissions that exceed 
levels demonstrated in the performance test if the operating parameters 
are not properly controlled. An explanation of these nonlinear 
relationships, including examples that explain why this relationship 
can result in daily emissions that exceed levels demonstrated in the 
performance test, are included in the Final Technical Support 
Document.192 Thus, at least in theory, an environmental 
benefit can result from shorter averaging periods, including ten-minute 
rolling averages and perhaps instantaneous readings in certain 
situations.
---------------------------------------------------------------------------

    \192\ See USEPA, ``Final Technical Support Document for 
Hazardous Waste Combustor MACT Standards, Volume IV: Compliance With 
the Hazardous Waste Combustor Standards, July 1999, Chapters 2 and 
3.
---------------------------------------------------------------------------

    We also acknowledge, however, that the Agency's ability to assess 
this potential benefit in practice for all hazardous waste combustors 
affected by this final rule is limited significantly by the paucity of 
short-term, minute-by-minute, operating parameter data. Without this 
data we cannot effectively evaluate whether operating parameter 
excursions occur to an extent that warrant national ten-minute 
averaging period requirements for all hazardous waste combustors. We 
therefore conclude that averaging period requirements shorter than 
those required by existing BIF regulations are not now appropriate for 
adoption on a national level, and do not adopt ten-minute averaging 
period requirements in this rulemaking.
    We maintain, however, that there may be site-specific circumstances 
that warrant averaging periods shorter than one hour in duration, 
including possibly instantaneous measurements. Regulatory officials may 
determine, on a site-specific basis, that shorter averaging periods are 
necessary to better assure compliance with the emission standards. The 
provisions in Sec. 63.1209(g)(2) authorize the regulatory official to 
make such a determination. Factors that may be considered when 
determining whether shorter averaging periods are appropriate include 
(1) the ability of a source to effectively control operating parameter 
excursions to levels achieved during the performance test; (2) the 
source's previous compliance history regarding operating parameter 
limit exceedances; and (3) the difference between the source's 
performance test emission levels and the relevant emission standard. 
For additional information, see the Final Technical Support Document, 
Volume 4, Chapter 2.
    d. What Is the Basis for 12-Hour Rolling Averages for Feedrates? 
The rule requires 12-hour averages for the feedrate of mercury, 
semivolatile metals, low volatile metals, chlorine, and ash (for 
incinerators) because feedrate and emissions are, for the most part, 
linearly

[[Page 52921]]

related. A 12-hour averaging period for feedrates is appropriate 
because it is the upper end of the range of time required to perform 
three runs of a comprehensive performance test. Thus, a 12-hour 
averaging period will ensure (if all other factors affecting emissions 
are constant) that emissions will not exceed performance test levels 
during any interval of time equivalent to the time required to conduct 
a performance test. A 12-hour averaging period is also achievable and 
appropriate from a compliance perspective because the emission 
standards are based on emissions data obtained over (roughly) these 
sampling periods.193
---------------------------------------------------------------------------

    \193\ See Chemical Waste Management v. EPA, 976 F.2d, 2, 34 
(D.C. Cir. 1992) (It is inherently reasonable to base compliance on 
the same type of data used to establish the requirement).
---------------------------------------------------------------------------

    e. Has the Agency Over-Specified Compliance Requirements? Some 
commenters state that the Agency is over-specifying compliance 
requirements by requiring limits on many operating parameters, 
requiring dual ten-minute and hourly rolling average limits on many 
parameters, and requiring that sources interlock the operating 
parameter limits with the automatic waste feed cutoff system. These 
commenters wrote that this compliance regime may lead to system over-
control and instability, and an unreasonable and unnecessary increase 
in automatic waste feed cutoffs, a result that is contrary to good 
process control principles. They propose that we work with industry to 
develop a process control system and performance specification 
regulatory approach to establish minimum system standards. These would 
include: (1) Minimum process instrument sampling time; (2) maximum 
calculation capability for output signals; (3) minimum standard for 
process control sequences; and (4) minimum requirements for 
incorporating automatic waste feed cutoffs into the control scheme. The 
specifications would be incorporated into guidance, rather than 
regulation. Commenters suggest that the rule should only specify 
general goals, similar to the guidance approach we took for hazardous 
waste incinerators in the 1981 RCRA regulations.194
---------------------------------------------------------------------------

    \194\ The incinerator regulations promulgated in 1981, at the 
outset of the RCRA regulatory program, used such a general guidance 
approach. However, sources have had over 15 years since then to gain 
experience with process control techniques associated with the 
combustion of hazardous waste.
---------------------------------------------------------------------------

    We evaluated these comments carefully, balancing the need to 
provide industry with operational flexibility with the need for 
compliance assurance. As previously discussed, we are not adopting ten-
minute averaging period requirements in this rulemaking, although it 
can be imposed on a site-specific basis under appropriate 
circumstances. This addresses commenter's concerns that relate to the 
complexity of the proposed dual averaging period requirements. We 
acknowledge, however, that today's rule requires that more operating 
parameter limits be interlocked to the automatic waste feed cutoff 
system than is currently required by RCRA regulations. Nonetheless, we 
conclude that the compliance regime of today's final rule is necessary 
to ensure compliance with the emission standards and will not overly 
constrain process control systems for the following reasons.
    Automatic waste feed cutoffs are (by definition) automatic, and the 
control systems used to avoid automatic waste feed cutoffs require 
adequate response time and are primarily site-specific in design. The 
closer a source pushes the edge of the operating envelope, the better 
that control system must perform to ensure that an operating parameter 
limit (and emission standard) is not exceeded. Therefore, a source has 
extensive control over the impact of these requirements.
    Under the compliance regime of today's rule, sources will continue 
to perform comprehensive performance testing under ``worst case'' 
conditions as they currently do under RCRA requirements to establish 
limits on operating parameters that are well beyond normal levels. This 
cushion between normal operating levels and operating parameter limits 
enables the source to take corrective measures well before a limit is 
about to be exceeded, thus avoiding an automatic waste feed cutoff.
    Regulatory officials do not have the extensive resources that would 
be required to develop and implement industry-specific control 
guidelines and we are not confident that this approach would provide 
adequate compliance assurance. Although specifying only emissions 
standards and leaving the compliance method primarily up to the source 
and the permit writer (aided by guidance) would provide flexibility, it 
would place a burden on the permit writers and the source during the 
development and approval of the performance test plan and the finding 
of compliance subsequent to Notification of Compliance. In addition, 
this level of interaction between permitting officials and the source 
is contrary to our policy of structuring the MACT standards to be as 
self-implementing as possible.195 The Agency therefore 
maintains its position that the compliance scheme adopted in today's 
rule, is appropriate.
---------------------------------------------------------------------------

    \195\ The time that would be associated with this type of review 
and negotiation between permit writer and source would be better 
spent on developing, reviewing, and approving the comprehensive 
performance test plan under today's compliance regime.
---------------------------------------------------------------------------

    f. Why Isn't Risk Considered in Determining Averaging Periods? 
Several commenters state that long averaging periods (e.g., monthly 
metal feedrate rolling averages) for the operating parameter limits and 
CEMS-monitored emission standards would be appropriate. These 
commenters believe that long averaging periods would be appropriate 
given that the Agency has performed a risk assessment and concluded 
that the emission standards would be protective over long periods of 
exposure. They state that long averaging periods would ensure that 
emissions are safe and reduce compliance costs.
    Consideration of risk is not an appropriate basis for determining 
averaging periods to ensure compliance with the technology-based MACT 
emission standards.196 As previously stated, we must 
establish averaging periods that ensure compliance with the emission 
standard for time durations equivalent to the emission sampling periods 
used to demonstrate compliance. Longer averaging periods would not 
ensure compliance with the emission standard because many of the 
operating parameters do not relate to emissions linearly.
---------------------------------------------------------------------------

    \196\ We note, however, that within eight years of promulgating 
MACT standards for a source category, we must consider risk in 
determining under section 112(f) whether standards more stringent 
than MACT are necessary to provide an ample margin of safety to 
protect public health and the environment.
---------------------------------------------------------------------------

    In addition, a longer averaging period is not warranted even for 
those operating parameters than may relate linearly to emissions 
because this would allow a source to emit hazardous air pollutants in 
excess of the emission standard for times periods equivalent to the 
stack emission sampling periods used to demonstrate compliance. For 
example, a monthly averaging period for metal feedrates could result in 
a source emitting metals at a level three times the regulatory standard 
continuously for a one week period.197 This would not be 
consistent with the level of control that was achieved by the best 
performing sources in our data base. Modifying the results of the MACT 
process based on risk considerations is thus contrary to Congressional 
intent that MACT

[[Page 52922]]

standards, at a minimum, must represent the level of control being 
achieved by the average of the best performing 12 percent of the 
sources. We therefore conclude that we must limit averaging times at 
least to time durations equivalent to the emission sampling periods 
used to demonstrate compliance.
---------------------------------------------------------------------------

    \197\ For this to occur, the source would have to emit metals 
far below the standard for time periods before and after this one-
week period.
---------------------------------------------------------------------------

    g. Will Relaxing Feedrate Averaging Times Increase Environmental 
Loading? One commenter questions whether relaxing the averaging time 
for the feedrate of metals and chlorine from an hourly rolling average 
under current RCRA regulations to the 12-hour rolling average of 
today's rule would increase total environmental loading of pollutants 
and be counter to the Agency's pollution prevention objectives. 
Contrary to the commenter's concern, we conclude that today's rule will 
decrease environmental loading of hazardous air pollutants because the 
emission standards are generally more stringent than current RCRA 
standards. Today's standards more than offset any difference in 
environmental loading associated with longer averaging times. As 
previously discussed, the averaging periods in today's rule were chosen 
to ensure compliance with the emission standard for intervals of time 
equivalent to the time required to conduct a performance test.
    Although current RCRA standards generally establish hourly rolling 
averages for the feedrate of metals, sources are actually allowed to 
establish up to 24-hour rolling averages for arsenic, beryllium, 
chromium, cadmium, and lead, provided they restrict the feedrate of 
these metals at any time to ten times what would be normally allowed 
under an hourly rolling average basis. For these reasons, the 
commenter's concern is not persuasive.
3. How Are Performance Test Data Averaged To Calculate Operating 
Parameter Limits?
    The rule specifies which of two techniques you must use to average 
data from the comprehensive performance test to calculate limits on 
operating parameters: (1) Calculate the limit as the average of the 
maximum (or minimum, as specified) rolling averages for each run of the 
test; or (2) calculate the limit as the average of the test run 
averages for each run of the test.
    Hourly rolling averages for two parameters--combustion gas flowrate 
(or kiln production rate as a surrogate) and hazardous waste feedrate--
are based on the average of the maximum hourly rolling averages for 
each run. Hourly rolling average and 12-hour rolling average limits for 
all other parameters, however, are based on the average level occurring 
during the comprehensive performance test. We determined that this more 
conservative approach is appropriate for these parameters because they 
can have a greater effect on emissions, and because it is consistent 
with how manual method emissions results are determined.198
---------------------------------------------------------------------------

    \198\ Manual method emission test results for each run 
represents average emissions over the entire run.
---------------------------------------------------------------------------

    These are examples of how the averages work. The hourly rolling 
average hazardous waste feedrate limit for a source is calculated using 
the first technique. If the highest hourly rolling averages for each 
run of the comprehensive performance test were 200 lbs/hour, 210 lbs/
hr, 220 lbs/hr, the hourly rolling average feedrate limit would be 210 
lbs/hr.
    The second approach uses the average of the test run averages for a 
given test condition to calculate the limit. Each test run average is 
calculated by summing all the one-minute readings within the test run 
and dividing that sum by the number of one-minute readings. For 
example, if: (1) The sum of all the one-minute semivolatile metal 
feedrate readings for each run within a test condition is 2,400 lbs/
hour, 2,500 lbs/hour, and 2,600 lbs/hour; and (2) there are 240, 250, 
and 200 one-minute readings in each run, respectively; then (3) the 
average feedrate for each of these three runs is 10 lbs/hour, 10 lbs/
hour, and 13 lbs/hour, respectively. The 12-hour rolling average 
semivolatile metal feed rate limit for this example is the average of 
these three values: 11 lbs/hour. This averaging methodology is not 
equivalent to an approach where the limit is calculated by taking the 
time-weighted average over all three runs within the test condition, 
because, as noted by the example, sampling times may be different for 
each run. The time-weighted average feedrate over all three test runs 
for the previous example is equivalent to 10.9 lbs/hr.199 
Although the two averaging techniques may not result in averages that 
are significantly different, we conclude that basing the limits on the 
average of the test run averages is more appropriate, because this 
approach is identical to how we determine compliance with the emission 
standards.
---------------------------------------------------------------------------

    \199\ This time weighted average is calculated by summing all 
the one-minute feedrate values in the test condition and dividing 
that sum by the number of one minute readings in the test condition.
---------------------------------------------------------------------------

    These averaging techniques are the same as we proposed (see 61 FR 
at 17418).200 A number of commenters object to the more 
conservative second technique of basing the limits on the average 
levels that occur during the test. The commenters claim that this 
approach ensures a source would not comply with the limits 50% of the 
time when operating under the same conditions as the performance test. 
Further, they are concerned that this approach would establish 
operating parameter limits that would ``ratchet'' emissions to levels 
well below the standards, and further ratcheting would occur with each 
subsequent performance test (i.e., because the current operating limits 
could not be exceeded during subsequent performance testing). Some 
commenters prefer the approach of setting the limit as the average of 
the highest (or lowest) rolling average from each run, technique one 
above, which is the same approach used in the BIF rule.
---------------------------------------------------------------------------

    \200\ Except that average hourly rolling average limits are 
calculated as the average of the test run averages rather than 
simply the average over all runs as proposed.
---------------------------------------------------------------------------

    Notwithstanding the conservatism of the promulgated approach 
(technique two above) for many operating parameter limits, we maintain 
that the approach results in achievable limits and is necessary to 
ensure compliance with the emission standards. Comprehensive 
performance tests are designed to demonstrate compliance with the 
emission standards and establish corresponding operating parameter 
limits. Thus, sources will operate under ``worst-case'' conditions 
during the comprehensive performance tests, just as they do currently 
for RCRA trial burns. Given that the source can readily control (during 
the performance test and thereafter) the parameters for which limits 
are established based on the average of the test run averages during 
performance testing (i.e., rather than on the average of the highest 
(or lowest) hourly rolling averages), and that these parameters will be 
at their extreme levels during the performance test, the limits are 
readily achievable.
    There may be situations, however, where a source cannot 
simultaneously demonstrate worst-case operating conditions for all the 
regulated operating parameters. An example of this may be minimum 
combustion chamber temperature and maximum temperature at the inlet to 
the dry particulate matter control device because when the combustion 
chamber temperature is minimized, the inlet temperature to the control 
device may also be minimized. Sources should consult permitting 
officials to resolve

[[Page 52923]]

compliance difficulties associated with conflicting operating 
parameters. Potential solutions to conflicting parameters could be to 
conduct the performance test under two different modes of operation to 
set these conflicting operating parameter limits, or for the 
Administrator to use the discretionary authority provided by 
Sec. 63.1209(g)(2) to set alternative operating parameter limits.
    We address commenters' concern that subsequent performance tests 
would result in a further ratcheting down of operating parameter limits 
by waiving the operating limits during subsequent comprehensive 
performance tests (see Sec. 63.1207(h)). The final rule also waives 
operating limits for pretesting prior to comprehensive performance 
testing for a total operating time not to exceed 720 hours. See 
discussion in Part Five, Section VI for more information on this 
provision.
    Some commenters suggest that we use a statistical analysis to 
determine rolling average limits, such that the limits are calculated 
as the mean plus or minus three standard deviations of all rolling 
averages for all runs. Commenters state that this would ensure that the 
operating parameter limits are achievable. If such an approach were 
adopted, there would be no guarantee that a source is maintaining 
compliance with the emission standards for the time durations of the 
manual stack sampling method used to demonstrate compliance during the 
comprehensive performance test. Such an approach could conceivably 
encourage a source to intentionally vary operating parameter levels 
during the comprehensive performance test to such an extent that the 
statistically-derived rolling average limits would be significantly 
higher than the true average of the test condition. This could also 
result in widely varying statistical correction factors from one source 
to another, which is undesirable for reasons of consistency and 
fairness.
    Such a statistical approach prevents us from establishing the 
minimum emission standards that Congress generally envisioned under 
MACT because we would not be assured that the sources are achieving the 
emission standard. We would also have difficulty estimating 
environmental benefits if this statistical approach were used because 
we would not know what level of emission control each source achieves. 
Again, the methodology promulgated for averaging performance test data 
to calculate operating parameter limits results in limits that are 
achievable and necessary to ensure compliance with the emission 
standards for time durations equivalent to emission sampling periods.
    Several commenters oppose the compliance regime whereby limits on 
operating parameters are established during performance testing. They 
are concerned that this approach encourages sources to operate under 
worst-case conditions during testing. One commenter states that this 
approach effectively punishes sources for demonstrating emissions 
during their performance test that are lower than the standards (i.e., 
by establishing limits on operating parameters that would be well below 
those needed to comply with the standards).
    We understand these concerns, but absent the availability of 
continuous emissions monitoring systems, we are unaware of another 
compliance assurance approach that effectively addresses the (perhaps 
unique) problem posed by hazardous waste combustors. The Agency is 
using this same approach to implement the RCRA regulations for these 
sources. Compliance assurance for hazardous waste combustors cannot be 
maintained using the general provisions of Subpart A in Part 63--
procedures that apply to all MACT sources unless we promulgate 
superseding provisions for a particular source category. Those 
procedures require performance testing under normal operating 
conditions, but operating limits are not established based on 
performance test operations. This approach is appropriate for most 
industrial processes because process constraints and product quality 
typically limit ``normal'' operations to a fairly narrow range that is 
easily defined.
    Hazardous waste combustors may be somewhat unique MACT sources, 
however, in that the characteristics of the hazardous waste feed (e.g., 
metals concentration, heating value) can vary over a wide range and 
have a substantial effect on emissions of hazardous air pollutants. In 
addition, system design, operating, and maintenance features can 
substantially affect pollutant emissions. This is not the same 
situation for many other MACT source categories where feedstream 
characteristics and system design, operation, and maintenance features 
must be confined to a finite range so that the source can continue to 
produce a product. Hazardous waste incinerators do not have such 
inherent controls (i.e., because they provide a waste treatment service 
rather than produce a product), and cement and lightweight aggregate 
kilns can vary substantially hazardous waste characteristics in the 
fuel, as well as system design, operation, and maintenance features and 
still produce marketable product.
    To address commenters' concerns at least in part, however, we have 
included a metals feedrate extrapolation provision in the final rule. 
This will reduce the incentive to spike metals in feedstreams during 
performance testing (and thus reduce the cost of testing, the hazard to 
test crews, and the environmental loading) by explicitly allowing 
sources to request approval to establish metal feedrate limits based on 
extrapolating upward from levels fed during performance testing. See 
discussion in Section VII.D.4 below, and Secs. 63.1209(l)(1) and 
63.1209(n)(2)(ii).
4. How Are the Various Types of Operating Parameters Monitored or 
Established?
    The operating parameters for which you must establish limits can be 
categorized according to how they are monitored or established as 
follows: (1) Operating parameters monitored directly with a continuous 
monitoring system; (2) feedrate limits; and (3) miscellaneous operating 
parameters. (Each of these parameters is discussed in Section VII.D 
below.)
    a. What Operating Parameters Are Monitored Directly with a 
Continuous Monitoring System? Operating parameters that are monitored 
directly with a continuous monitoring system include: Combustion gas 
temperature in the combustion chamber and at the inlet to a dry 
particulate matter control device; baghouse pressure drop; for wet 
scrubbers, pressure drop across a high energy wet scrubber (e.g., 
venturi, calvert), liquid feed pressure, pH, liquid-to-gas ratio, 
blowdown rate (coupled with either a minimum recharge rate or a minimum 
scrubber water tank volume or level), and scrubber water solids 
content; minimum power input to each field of an electrostatic 
precipitator; flue gas flowrate or kiln production rate; hazardous 
waste flowrate; and adsorber carrier stream flowrate. These operating 
parameters are monitored and recorded on a continuous basis during the 
comprehensive performance test and during normal operations. The 
continuous monitoring system also transforms and equates the data to 
its associated averaging period during the performance test so that 
operating parameter limits can be established. The continuous 
monitoring system must operate in conformance with Sec. 63.1209(b).
    b. How Are Feedrate Limits Monitored? Feedrate limits are monitored 
by knowing the concentration of the regulated parameter

[[Page 52924]]

in each feedstream and continuously monitoring the flowrate of each 
feedstream. See Sec. 63.1209(c)(4). You must establish limits on the 
feedrate parameters specified in Sec. 63.1209, including: semivolatile 
metals, low volatile metals, mercury; chlorine, ash (for incinerators), 
activated carbon, dioxin inhibitor, and dry scrubber sorbent. The 
flowrate continuous monitoring system must operate in conformance with 
Sec. 63.1209(b).
    c. How Are the Miscellaneous Operating Parameters Monitored/
Established? Other operating parameters specified in Sec. 63.1209 
include: Specifications for activated carbon, acid gas sorbent, 
catalyst for catalytic oxidizers, and dioxin inhibitor; and maximum age 
of carbon in a carbon bed. Because each of these operating parameters 
may be unique to your source, you are expected to characterize the 
parameter (e.g., using manufacturer specifications) and determine how 
it will be monitored and recorded. This information must be included in 
the comprehensive performance test plan that will be reviewed and 
approved by permitting officials.
5. How Are Rolling Averages Calculated Initially, Upon Intermittent 
Operations, and When the Hazardous Waste Feed Is Cut Off?
    a. How Are Rolling Averages Calculated Initially? You must begin 
complying with the limits on operating parameters specified in the 
Documentation of Compliance on the compliance date.201 See 
Sec. 63.1209(b)(5)(i). Given that the one-hour, and 12-hour rolling 
averages for limits on various parameters must be updated each minute, 
this raises the question of how rolling averages are to be calculated 
upon initial startup of the rolling average requirements. We have 
determined that an operating parameter limit will not become effective 
on the compliance date until you have recorded enough monitoring data 
to calculate the rolling average for the limit. For example, the hourly 
rolling average limit on the temperature at the inlet to an 
electrostatic precipitator does not become effective until you have 
recorded 60 one-minute average temperature values on the compliance 
date. Given that compliance with the standards begins nominally at 
12:01 am on the compliance date, the hourly rolling average temperature 
limit does not become effective as a practical matter until 1:01 am on 
the compliance date. Similarly, the 12-hour rolling average limit on 
the feedrate of mercury does not become effective until you have 
recorded 12 hours of one-minute average feedrate values after the 
compliance date. Thus, the 12-hour rolling average feedrate limits 
become effective as a practical matter at 12:01 pm on the compliance 
date.
---------------------------------------------------------------------------

    \201\ The operating parameters for which you must specify limits 
are provided in Sec. 63.1209. You must include these limits in the 
Documentation of Compliance, and you must record the Documentation 
of Compliance in the operating record.
---------------------------------------------------------------------------

    Although we did not specifically address this issue at proposal, 
commenters raised the question in the context of CEMS. Given that the 
same issue applies to all continuous monitoring systems, we adopt the 
same approach for all continuous monitoring systems, including CEMS. 
See discussion below in Section VII.C.5.b. We adopt the approach 
discussed here because a rolling average limit on an operating 
parameter does not exist until enough one-minute average values have 
been obtained to calculate the rolling average.
    b. How Are Rolling Averages Calculated upon Intermittent 
Operations? We have determined that you are to ignore periods of time 
when one-minute average values for a parameter are not recorded for any 
reason (e.g., source shutdown) when calculating rolling averages. See 
Sec. 63.1209(b)(5)(ii). For example, consider how the hourly rolling 
average for a parameter would be calculated if a source shuts down for 
yearly maintenance for a three week period. The first one-minute 
average value recorded for the parameter for the first minute of 
renewed operations is added to the last 59 one-minute averages before 
the source shutdown for maintenance to calculate the hourly rolling 
average.
    We adopt this approach for all continuous monitoring systems, 
including CEMS (see discussion below in Section VII.C.5.b) because it 
is simple and reasonable. If, alternatively, we were to allow the 
``clock to be restarted'' after an interruption in recording parameter 
values, a source may be tempted to ``clean the slate'' of high values 
by interrupting the recording of the parameter values (e.g., by taking 
the monitor off-line for a span or drift check). Not only would this 
mean that operating limits would not be effective again until an 
averaging period's worth of values were recorded, but it would be 
contrary to our policy of penalizing a source for operating parameter 
limit exceedances by not allowing hazardous waste burning to resume 
until the parameter is within the limit. Not being able to burn 
hazardous waste during the time that the parameter exceeds its limit is 
intended to be an immediate economic incentive to minimize the 
frequency, duration, and intensity of exceedances.
    c. How Are Rolling Averages Calculated when the Hazardous Waste 
Feed Is Cut Off? Even though the hazardous waste feed is cut off, you 
must continue to monitor operating parameters and calculate rolling 
averages for operating limits. See Sec. 63.1209(b)(5)(iii). This is 
because the emission standards and operating parameter limits continue 
to apply even though hazardous waste is not being burned. See, however, 
the discussion in Part Five, Sections I.C and I.D above for exceptions 
(i.e., when a hazardous waste combustor is not burning hazardous waste, 
the emission standards and operating requirements do not apply: (1) 
During startup, shutdown, and malfunctions; or (2) if you document 
compliance with other applicable CAA section 112 or 129 standards).
6. How Are Nondetect Performance Test Feedstream Data Handled?
    You must establish separate feedrate limits for semivolatile metal, 
low volatile metal, mercury, total chlorine, and/or ash for each 
feedstream for which the comprehensive performance test feedstream 
analysis determines that these parameters are not present at detectable 
levels. The feedrate limit must be defined as nondetect at the full 
detection limit achieved during the performance test. See 
Sec. 63.1207(n).
    You will not be deemed to be exceeding this feedrate limit when 
detectable levels of the constituent are measured, provided that: (1) 
Your total system constituent feedrate, considering the detectable 
levels in the feedstream (whether above or below the detection limit 
achieved during the performance test) that is limited to nondetect 
levels, is below your total system constituent feedrate limit; or (2) 
except for ash, your uncontrolled constituent emission rate for all 
feedstreams, calculated in accordance with the procedures outlined in 
the performance test waiver provisions (see Sec. 63.1207(m)) are below 
the applicable emission standards.
    We did not address in the April 1996 NPRM how you must handle 
nondetect compliance test feedstream results when determining feedrate 
limits, nor did commenters suggest an approach. After careful 
consideration, we conclude that the approach presented above is 
reasonable and appropriate.
    The LWAK industry has expressed concern about excessive costs with 
compliance activities that would be needed for the mercury standard. 
They

[[Page 52925]]

claim that the increased costs associated with achieving lower mercury 
detection limits are large, and does not result in significant 
environmental benefits.
    The final rule includes four different methods an LWAK can use to 
comply with the mercury emission standard in order to provide maximum 
flexibility. The basic compliance approach (described below) does not 
require an LWAK to achieve specified minimum mercury detection limits 
for mercury standard compliance purposes.202 Under this 
approach, analytical procedures that achieve given detection limits are 
evaluated on a site-specific basis as part of the waste analysis plan 
review and approval process, which is submitted as part of the 
performance test plan. An LWAK can make the case to the regulatory 
official that the increased costs associated with achieving a very low 
mercury detection limit is not warranted. We therefore do not believe 
that the LWAK industry will incur significant additional analytical 
costs over current practices for daily mercury compliance activities. 
We acknowledge, however, that site-specific circumstances may lead a 
regulatory official to conclude that lower detection limits are 
warranted. To better understand this concept, the following paragraphs 
summarize this basic mercury emission standard compliance scheme and 
discusses why a regulatory official may determine, on a site-specific 
basis, that lower detection limits are needed to better assure 
compliance with the emission standard.
---------------------------------------------------------------------------

    \202\ The other three approaches are (1) performance test waiver 
provisions (see preamble, part 5, section X.B); (2) alternative 
standards when raw materials cause an exceedance of the emission 
standard (see preamble, part 5, section X.A); and, (3) alternative 
mercury standards for kilns that have non-detect levels of mercury 
in the raw material (see preamble, part 5, section X.A). These 
mercury standard compliance alternatives require a source to achieve 
feedstream detection limits that either ensure compliance with an 
emission standard or ensure compliance with a hazardous waste 
feedrate limit that is used in lieu of a numerical emission 
standard. See previous referenced preamble for further discussion.
---------------------------------------------------------------------------

    Under this basic approach, the source conducts a performance test 
and samples the emissions for mercury to demonstrate compliance with 
the emission standard. To ensure compliance with the emission standard 
during day-to-day operations, the source must comply with mercury 
feedrate limits that are based on levels achieved during the 
performance test. A source must establish separate mercury feedrate 
limits for each feed location. As previously discussed in this section, 
for feedstreams where mercury is not present at detectable levels, the 
feedrate limit must be defined as ``nondetect at the full detection 
limit''.
    There is no regulatory requirement for a source to achieve a given 
detection limit under this approach. We acknowledge, however, that 
feedstream detection limits can be high enough such that a mercury 
feedrate limit that is based on nondetect performance test results may 
not completely ensure compliance with the emission standard during day-
to-day operations. For example, the LWAK industry has indicated that a 
hazardous waste mercury detection limit of 2 ppm is reasonably 
achievable at an on-site laboratory. If we assume that mercury is 
present in the hazardous waste at a concentration of 1.99 ppm (just 
below the detection limit), the expected mercury emission concentration 
would be approximately 80 g/dscm, which is above the 
standard.203 (Note also that this does not consider mercury 
emission contributions from the raw material.) This is not to say that 
this LWAK will be exceeding the mercury emission standard during day-
to-day operations. However, their inability to achieve low mercury 
detection limits results in less assurance that the source is 
continuously complying with the emission standard.
---------------------------------------------------------------------------

    \203\ This assumes that all the mercury fed to the unit is 
emitted, and is based on typical LWAK gas emission rates.
---------------------------------------------------------------------------

    The regulatory official should consider such emission standard 
compliance assurance concerns when reviewing the waste analysis plan to 
determine if lower detection limits are appropriate (if, in fact such 
lower detection limits are reasonably achievable). Factors that should 
be considered in this review should include: (1) The costs associated 
with achieving lower detection limits; and (2) the estimated maximum 
mercury concentrations that can occur if the source's feedstreams 
contain mercury just below the detection limit (as described above).
C. Which Continuous Emissions Monitoring Systems Are Required in the 
Rule?
    Although the final rule does not require you to use continuous 
emissions monitoring systems (CEMS) for parameters other than carbon 
monoxide, hydrocarbon, oxygen, and particulate matter 204 we 
have a strong preference for CEMS because they: (1) Are a direct 
measure of the hazardous air pollutant or surrogate for which we have 
established emission standards; (2) lead to a high degree of certainty 
regarding compliance assurance; and (3) allow the public to be better 
informed of what a source's emissions are at any time. Additionally, 
from a facility standpoint, CEMs provide you with real time feedback on 
your combustion operations and give you a greater degree of process 
control. Therefore, we encourage you to use CEMS for other parameters 
such as total mercury, multimetals, hydrochloric acid, and chlorine 
gas. You may use the alternative monitoring provision of Sec. 63.8(f) 
to petition the Administrator (i.e., permitting officials) to use CEMS 
to document compliance with the emission standards in lieu of emissions 
testing and the operating parameter limits specified in Sec. 63.1209. 
You may submit the petition at any time, such as with the comprehensive 
performance test plan. See Section VII.C.5.c below for a discussion of 
the incentives for using CEMS.
---------------------------------------------------------------------------

    \204\ The final rule requires that particulate matter CEMS be 
installed, but defers the effective date of the requirement to 
install, calibrate, maintain, and operate PM CEMS until these 
actions can be completed.
---------------------------------------------------------------------------

    In this section, we discuss the status of development of particular 
CEMS and provide guidance on issues that pertain to case-by-case 
approval of CEMS in lieu of compliance using operating parameter limits 
and periodic emissions testing. Key issues include appropriate CEMS 
performance specifications, reference methods for determining the 
performance of CEMS, averaging periods, and temporary waiver of 
emission standards if necessary to enable sources to correlate 
particulate matter CEMS to the reference method.
1. What Are the Requirements and Deferred Actions for Particulate 
Matter CEMS?
    In the April 1996 NPRM, we proposed the use of particulate matter 
CEMS to document compliance with the particulate matter emission 
standards. Particulate matter CEMS are used for compliance overseas 
205, but are not yet a regulatory compliance tool in the 
U.S. Concurrent with this proposal, we undertook a demonstration of 
particulate matter CEMS at a hazardous waste incinerator to determine 
if these CEMS were feasible in U.S. applications. We selected the test 
incinerator as representative of a worst-case application for a 
particulate matter CEMS at any hazardous waste

[[Page 52926]]

combustor. It was important to document feasibility of the CEMS at a 
worst-case application to minimize time and resources needed to 
determine whether the CEMS were suitable for compliance assurance at 
all hazardous waste combustors.
---------------------------------------------------------------------------

    \205\ The EU guidelines for hazardous waste combustion state 
that particulate matter is a parameter for which compliance must be 
documented continuously. In addition, proposals from vendors that we 
received in response to our February 27, 1996 NODA (see 61 FR 7262) 
indicate that there are many installations elsewhere overseas where 
particulate matter CEMS are used for compliance assurance.
---------------------------------------------------------------------------

    We published preliminary results of our CEMS testing and sought 
comment on our approach to demonstrating particulate matter CEMS in the 
March 1997 NODA. We then revised our approach and sought comment on the 
final report in the December 1997 NODA. The December 1997 NODA also 
clarified several issues that came to light during the demonstration 
test pertaining to the manual reference method, particulate matter 
CEMS, and general quality assurance issues. These clarifications were 
embodied in a new manual method, Method 5-I (Method 5i), a revision to 
the proposed Performance Specification 11 for particulate matter CEMS, 
and a new quality assurance procedure, Procedure 2.
    We believe that our tests adequately demonstrate that particulate 
matter CEMS are a feasible, accurate, and reliable technology that can 
and should be used for compliance assurance. In addition, preliminary 
analyses of the cost of PM CEMS applied to hazardous waste combustors 
suggest that these costs are reasonable. Accordingly, the final rule 
contains a requirement to install PM CEMS. However, we agree with 
comments that indicate a need to develop source-specific performance 
requirements for particulate matter CEMS and to resolve other 
outstanding technical issues. These issues include all questions 
related to implementation of the particulate matter CEMS requirement 
(i.e. relation to all other testing, monitoring, notification, and 
recordkeeping), relation of the particulate matter CEMS requirement to 
the PM emission standard, as well as technical issues involving 
performance, maintenance and correlation of the particulate matter CEMS 
itself. These issues will be addressed in a subsequent rulemaking. 
Therefore, we defer the effective date of this requirement pending 
further testing and additional rulemaking.
    As a result, in today's final rule, we require that particulate 
matter CEMS be installed at all hazardous waste burning incinerators, 
cement kilns, and lightweight aggregate kilns. However, since we have 
not finalized the performance specifications for the use of these 
instruments or resolved some of the technical issues noted above, we 
are deferring the effective date of the requirement to install, 
calibrate, maintain and operate particulate matter CEMS until these 
actions can be completed. The particulate matter CEMS installation 
deadline will be established through future rulemaking, along with 
other pertinent requirements, such as final Performance Specification 
11, Appendix F Procedure 2. Finally, it should be noted that EPA has a 
concurrent rulemaking process underway for nonhazardous waste burning 
cement kilns and plans to adopt the same approach in that rule.
2. What Are the Test Methods, Specifications, and Procedures for 
Particulate Matter CEMS?
    a. What Is Method 5i? We promulgate in the final rule a new manual 
method for measuring particulate matter, Method 5i. See appendix A to 
part 60. We first published this new method in the December 1997 NODA. 
One outgrowth of these particulate matter CEMS demonstration tests is 
that we made significant improvements in making low concentration 
Method 5 particulate measurements. We first discussed these 
improvements in the preliminary report released in the March 1997 NODA, 
and commenters to that NODA ask that these improvements be documented. 
We documented these improvements by creating Method 5i.
    We incorporated the following changes to Method 5 into Method 5i: 
Improved sample collection; minimization of possible contamination; 
Improved sample analysis; and an overall emphasis on elimination of 
systemic errors in measurement. These improvement achieved significant 
improvements in method accuracy and precision at low particulate matter 
concentrations, relative to Method 5.
    We are promulgating Method 5i today, in advance of any particulate 
matter CEMS requirement, for several reasons. We expect this new method 
will be preferred in all cases where low concentration (i.e., below 45 
mg/dscm (0.02 gr/dscf) 206) measurements are 
required for compliance with the standard. Given that all incinerators, 
nearly all lightweight aggregate kilns, and some cement kilns are 
likely to have emissions lower than 45 mg/dscm, we expect that Method 
5i will become the particulate method of choice for most hazardous 
waste combustors. In addition, we expect that Method 5i will be used to 
correlate manual method results to particulate matter CEMS outputs for 
those sources that elect to petition the Administrator to use a CEMS in 
lieu of operating parameter limits for compliance assurance with the 
particulate matter standard.207 This is because, unlike the 
worst-case particulate matter measurements normally used to verify 
compliance with the standard, low (or lower than normal) concentration 
particulate matter data are required to develop a good correlation 
between the CEMS output and the manual, reference method.
---------------------------------------------------------------------------

    \206\ As noted later in the text, the filter and assembly used 
for Method 5i is smaller than the one used for Method 5. This means 
that the Method 5i filter plugs more easily than the one used for 
Method 5. This issue becomes important at particulate matter 
concentrations above 45 mg/dscm, or 0.02 gr/dscf.
    \207\ As alluded to previously, sources may elect to use a CEMS 
to comply with the numerical value of the particulate matter 
emission standard on a six-hour rolling average in lieu of complying 
with operating parameter limits specified by Sec. 63.1209(m).
---------------------------------------------------------------------------

    Many of the issues commenters raise relate to how Method 5i should 
be used to correlate particulate matter CEMS outputs to manual method 
measurements. Even though we are deferring a CEMS requirement, we 
address several key issues here given that sources may elect to 
petition the Administrator under Sec. 63.8(f) to use a CEMS. This 
discussion may provide a better understanding on our thinking on 
particulate matter CEMS issues. In addition, certain comments are 
specific to how Method 5i is performed. These comments and our 
responses are relevant even if you use Method 5i only as a stack 
particulate method and not to correlate a particulate matter CEMS to 
the reference method.
    i. Why Didn't EPA Validate Method 5i Against Method 5? Several 
commenters recommend that we perform a full Method 301 validation to 
confirm that Method 5i is equivalent to Method 5. We determined that a 
full Method 301 validation is not necessary because the differences in 
the two methods do not constitute a major change in the way particulate 
samples are collected from an operational or an analytical standpoint. 
We validated the filter extraction and weighting process--the only 
modification from Method 5 (see ``Particulate Matter CEMS Demonstration 
Test Final Report,'' Appendix A, in the Technical Support Document 
208) `` and documented that Method 5i gives nearly identical 
results as Method 5. Therefore, we disagree with the commenters' 
underlying concern and conclude that Method 5i has been validated.
---------------------------------------------------------------------------

    \208\ See USEPA, ``Final Technical Support Document for 
Hazardous Waste Combustor MACT Standards, Volume IV: Compliance With 
the Hazardous Waste Combustor Standards,'' July 1999.
---------------------------------------------------------------------------

    ii. When Are Paired Trains Required? We have included in Method 5i 
a requirement that paired trains must be

[[Page 52927]]

used to increase method precision. This requirement applies whether you 
use Method 5i to demonstration compliance with the emission standard or 
to correlate a particulate matter CEMS. In addition, if you elect to 
petition the Administrator for approval to use a particulate matter 
CEMS and elect to use Method 5 to correlate the CEMS, you must also 
obtain paired Method 5 data to improve method precision and, thus, the 
correlation.
    During our CEMS testing, we collected particulate matter data using 
two simultaneously-conducted manual method sampling trains. We called 
the results from these simultaneous runs ``paired data.'' We discussed 
the use of paired trains in the December 1997 NODA as being optional 
but requested comment on whether we should require paired trains, state 
a strong preference for them, or be silent on the issue. Many 
commenters believe paired trains should be used at all times so 
precision can be documented. With these comments in mind, and 
consistent with our continued focus on the collection of high quality 
emission measurements, we include a requirement in Method 5i to obtain 
paired data. Method 5i also includes a minimum acceptable relative 
standard deviation between these data pairs. As discussed below, both 
data in the pair are rejected if the data exceed the acceptable 
relative standard deviation.
    To improve the correlation between the manual method and a 
particulate matter CEMS, we also recommend that sources electing to use 
Method 5 also obtain paired Method 5 data. Again, data sets that exceed 
an acceptable relative standard deviation, as discussed below, should 
be rejected. This recommendation will be implemented during the 
Administrator's review of your petition requesting use a particulate 
matter CEMS. If you elect to correlate the CEMS using Method 5, you are 
expected to include in your petition a statement that you will obtain 
paired data and will conform with our recommended relative standard 
deviation for the paired data.
    iii. What Are the Procedures for Identifying Outliers? We have 
established maximum relative standard deviation values for paired data 
for both Method 5i and Method 5. If a data pair exceed the relative 
standard deviation, the pair is identified as an outlier and is not 
considered in the correlation of a particulate matter CEMS with the 
reference method. In addition, Method 5i pairs that exceed the relative 
standard deviation are considered outliers and cannot be used to 
document compliance with the emission standard.
    In the initial phase of our CEMS tests, we established a procedure 
for eliminating imprecise data. This consisted of eliminating a set of 
paired data if the data disagree by more than some previously 
established amount. Two identical methods running at the same time 
should yield the same result; if they do not, the precision of both 
data is suspect. Commenters agree with the need to identify and 
eliminate imprecise data to enhance method precision. This is an 
especially important step when comparing manual particulate matter 
measurements to particulate matter CEMS measurements. As a result, we 
include criteria in Method 5i to ensure data precision.
    When evaluating the particulate matter CEMS Demonstration Test 
data, we screened the data to remove these precision outliers. Data 
outliers at that time were defined as paired data points with a 
relative standard deviation 209 of greater than 30 percent. 
We developed this 30% criterion by analyzing historical Method 5 data. 
Several commenters, including a particulate matter CEMS vendor with 
extensive European experience with correlation programs, recommend that 
we tighten the relative standard deviation criteria. We concur, because 
Method 5i is more precise than Method 5 given the improvements 
discussed above. Therefore, one would logically expect a reasonable 
precision criterion such as the relative standard deviation derived 
from Method 5i data to be less than a similarly reasonable one derived 
from Method 5 data. We investigated the particulate matter CEMS 
Demonstration Test data base as well other available Method 5i data 
(such as the data from a test program recently conducted at another US 
incinerator). We conclude that a 10% relative standard deviation for 
particulate matter emissions greater than or equal to 10 mg/dscm, 
increased linearly to 25% for concentrations down to 1 mg/dscm, is a 
better representation of acceptable, precise Method 5i paired data 
210. Data obtained at concentrations lower than 1 mg/dscm 
have no relative standard deviation limit.
---------------------------------------------------------------------------

    \209\ RSD, or ``relative standard deviation'', is a 
dimensionless number greater than zero defined as the standard 
deviation of the samples, divided by the mean of the samples. In the 
special case where only 2 data represent the sample, the mathematics 
of determining the relative standard deviation simplifies greatly to 
|CA-CB |/(CA + CB), 
where CA and CB are the concentration results 
from the two trains that represent the pair.
    \210\ See Chapter 11, Section 2 of the technical background 
document for details on the statistical procedures used to derive 
these benchmarks: USEPA, ``Final Technical Support Document for 
Hazardous Waste Combustor MACT Standards, Volume IV: Compliance With 
the Hazardous Waste Combustor Standards,'' July 1999.
---------------------------------------------------------------------------

    The relative standard deviation criterion for Method 5 data used 
for particulate matter CEMS correlations continues to be 30%.
    iv. Why Didn't EPA Issue Method 5i as Guidance Rather than 
Promulgating It as a Method? Most commenters state that Method 5i 
should be guidance rather than a published method and it should not be 
a requirement for performing particulate matter CEMS correlation 
testing or documenting compliance with the emission standard. In 
particular, several commenters in the cement kiln industry express 
concern over the limitations of Method 5i regarding the mass of 
particulate it could collect. This section addresses these concerns.
    We have promulgated Method 5i as a method because it provides 
significant improvement in precision and accuracy of low level 
particulate matter measurements relative to Method 5. Consequently, 
although Method 5i is not a required method, we expect that permitting 
officials will disapprove comprehensive performance test plans that 
recommend using Method 5 for low level particulate levels. Further, we 
expect that petitions to use a particulate matter CEMS that recommend 
performance acceptance criteria (e.g., confidence level, tolerance 
level, correlation coefficient) based on correlating the CEMS with 
Method 5 measurements will be disapproved. This is because we expect 
the CEMS to be able to achieve better acceptance criteria values using 
Method 5i (because it is more accurate and precise than Method 5), and 
expect better relative standard deviation between test pairs (resulting 
in lower cost of correlation testing because fewer data would be 
screened out as outliers).
    Given that we expect and want widespread use of Method 5i, and to 
ensure that its key provisions are followed, it is appropriate to 
promulgate it as a method rather than guidance. If the procedure were 
issued only as guidance, the source or stack tester could choose to 
omit key provisions, thus negating the benefits of the method.
    Relative to the direct reference in Method 5i that the method is 
``most effective for total particulate matter catches of 50 mg or 
less,'' this means the method is most effective at hazardous waste 
combustors with particulate matter emissions below approximately 45 mg/
dscm (0.02 gr/dscf). This applicability statement is not 
intended to be a bright line; total train catches exceeding 50 mg would 
not invalidate

[[Page 52928]]

the method. Rather, we include this guidance to users of the method to 
help them determine whether the method is applicable for their source. 
Note that this statement is found in the applicability section of the 
method, rather than the method description sections that follow. As 
such, the reference is clearly an advisory statement, not a quality 
assurance criterion. Total train catches above 50 mg are acceptable 
with the method and the results from such trains can be used to 
document compliance with the emission standard and for correlating 
CEMS. But, users of Method 5i are advised that problems (such as 
plugging of the filter) may arise when emissions are expected to exceed 
45 mg/dscm. 211
---------------------------------------------------------------------------

    \211\ Stack testers have developed ways to deal with plugging of 
a filter. Many stack testers simply remove the filter before it 
plugs, install a new, clean filter, and continue the sampling 
process where they left off with the old filter. The mass gain is 
then the total mass accumulated on all filters during the run. 
However, using multiple filters for a single run takes more time, 
not only to install the new filter but also to condition and weigh 
multiple filters for a single run. For Method 5i, it would also 
involve more capital cost because the stack tester would need more 
light-weight filter assemblies to perform the same number of runs. 
For these reasons and even though the situation can be acceptably 
managed, it is impractical to have the filter plug. This led to our 
recommendation that Method 5i is best suited for particulate matter 
(i.e., filter) loadings of at most 50 mg, or stack concentrations of 
less than 45 mg/dscm (roughly 0.02 gr/dscf).
---------------------------------------------------------------------------

    v. What Additional Costs Are Associated with Method 5i? Commenters 
raise several issues regarding the additional costs of performing 
Method 5i testing relative to using Method 5. There is an added cost 
for the purchase of new Method 5i filter housings. These new 
lightweight holders are the key addition to the procedure needed to 
improve precision and accuracy and represent a one-time expense that 
emission testing firms or sources that perform testing in-house will 
have to incur to perform Method 5i. We do not view this cost as 
significant and conclude that the use of a light-weight filter housing 
is a reasonable and appropriate feature of the method.
    Other commenters suggest that the requirement for pesticide-grade 
acetone in the version of Method 5i contained in the December 1997 NODA 
unnecessarily raises the cost of performing the method. Instead, they 
ask us to identify a performance level for the acetone instead of a 
grade requirement because it would allow test crews to meet that 
performance in the most economical manner. We agree that prescribing a 
certain type of acetone may unnecessarily increase costs and removed 
the requirement for pesticide-grade acetone. Accordingly, the same 
purity requirements cited in Method 5 for acetone are maintained for 
Method 5i. The prescreening of acetone purity in the laboratory prior 
to field use, consistent with present Method 5 requirements, is also 
maintained in Method 5i.
    Commenters make similar cost-related comments relative to the 
requirement for Teflon beakers. At the request of several 
commenters, we have expanded the requirement for Teflon 
beakers to allow the use of beakers made from other similar light-
weight materials. Because materials other than Teflon can 
be used to fabricate light-weight breakers, changing the requirement 
from a technology basis to a performance basis will reduce costs while 
achieving the performance goals of the method.
    There were no significant comments regarding the added cost of 
paired-train testing.
    vi. What Is the Practical Quantification Limit of the Method 5i 
Filter Sample? We received several comments related to the minimum 
detection limit of Method 5i, including: the minimum sample required, 
guidance on how long to sample, what mass should ideally be collected 
on any filter, and the practical quantification limit.
    Commenters are concerned that while we address the maximum amount 
of particulate matter the method could handle, we are silent on the 
issue of what minimum sample is required. This is important because 
analytical errors, such as weighing of the filters, tend to have the 
same error value associated with it irrespective of the mass loading. 
To address this concern, Method 5i provides guidance on determining the 
minimum mass of the collected sample based on estimated particulate 
matter concentrations.
    Related to the particulate mass collection issue is the issue of 
how long a user of Method 5i needs to sample in order to an adequate 
amount of particulate on the filter. The amount of particulate matter 
collected is directly related to time duration of the sampling period, 
i.e., the longer one samples, the more particulate is collected and 
vice-versa. Therefore, Method 5i provides guidance on selecting a 
suitable sampling time based on the estimated concentration of the gas 
stream.
    Both these issues directly relate to how much particulate matter 
should ideally be collected on any individual filter. Our experience 
indicates a minimum target mass is 10 to 20 mg.
    Finally, we conclude that the targeted practical quantification 
limit for Method 5i is 3.0 mg of sample. Discussion of how this 
quantification limit is determined is highly technical and beyond the 
scope of this preamble. See the technical support document for more 
details.212
---------------------------------------------------------------------------

    \212\ See USEPA, ``Final Technical Support Document for 
Hazardous Waste Combustor MACT Standards, Volume IV: Compliance With 
the Hazardous Waste Combustor Standards,'' July 1999.
---------------------------------------------------------------------------

    vii. How Are Blanks Used with Method 5i? Several commenters 
question the use of acetone blanks or made recommendations for 
additional blanks. We clarify in this section the collection and use of 
sample blank data.
    We recognize that high blank results can adversely effect the 
analytical results, especially at low particulate matter 
concentrations. To avoid the effect high blank results can have on the 
analytical results, today's Method 5i adopts a strategy similar to 
several of the organic compound test procedures (such as Method 23 in 
part 60 and Method 0010 in SW-846) that require collection of blanks 
but do not permit correction to the analytical results. Collection and 
analysis of blanks remains an important component in the sampling and 
analysis process for documenting the quality of the data, however. If a 
test run has high blank results, the data may be suspect. Permitting 
officials will address this issue on a case-by-case basis.
    The importance of minimizing contamination is stressed throughout 
Method 5i for both sample handling and use of high purity sample media. 
If proper handling procedures are observed, we expect that the blank 
values will be less than the method detection limit or within the value 
for constant weight determination (0.5 mg). Therefore, the allowance 
for blank correction that is provided in Method 5 is not permitted in 
Method 5i. The method also recommends several additional types of 
blanks to provide further documentation of the integrity and purity of 
the acetone throughout the duration of the field sampling program.
    b. What Is the Status of Particulate Matter CEMS Performance 
Specification 11 and Quality Assurance/Quality Control Procedure 2? We 
are not finalizing proposed Performance Specification 11 and Quality 
Assurance/Quality Control Procedure 2 because the final rule does not 
require the use of particulate matter CEMS. We considered stakeholder 
comments on these documents, however, and have incorporated many 
comments into the current drafts. We plan to publish these documents 
when we address the particulate matter CEMS requirement. In the 
interim, we will make them available as guidance to sources that are

[[Page 52929]]

considering the option of using a particulate matter CEMS to document 
compliance.
    c. How Have We Resolved Other Particulate Matter CEMS Issues? In 
this section we discuss two additional issues: (1) Why didn't we 
require continuous opacity monitors for compliance with the particulate 
matter standard for incinerators and lightweight aggregate kilns; and 
(2) can high correlation emissions testing runs exceed the particulate 
matter standard?
    i. Why Didn't We Require Continuous Opacity Monitors for Compliance 
Assurance for Incinerators and Lightweight Aggregate Kilns? As 
discussed elsewhere in today's notice, we require cement kilns to use 
continuous opacity monitors (COMS) to comply with a 20 percent opacity 
standard to ensure compliance with the particulate matter emission 
standard. This is the opacity component of the New Source Performance 
Standard for particulate matter for Portland cement plants. See 
Sec. 60.62. Because we are adopting the mass-based portion of the New 
Source Performance Standard for particulate matter as the MACT standard 
(i.e., 0.15 kg/Mg dry feed), the opacity component of the New Source 
Performance Standard is useful for compliance assurance.
    We do not require that incinerators and lightweight aggregate kilns 
use opacity monitors for compliance assurance because we are not able 
to identify an opacity level that is achievable by sources using MACT 
control and that would ensure compliance with the particulate matter 
standards for these source categories. This is the same issue discussed 
above in the context of particulate matter CEMS and is the primary 
reason that we are not requiring use of these CEMS at this time.
    Although we are requiring that cement kilns use COMS for compliance 
assurance, these monitors cannot provide the same level of compliance 
assurance as particulate matter CEMS. Opacity monitors measure a 
characteristic of particulate matter (i.e., opacity) and cannot 
correlate with the manual stack method as well as a particulate matter 
CEMS. COMS are particularly problematic for sources with small stack 
diameters (e.g., incinerators) and low emissions because both of these 
factors contribute to very low opacity readings which results in high 
measurement error as a percentage of the opacity value. Thus, we are 
obtaining additional data to support rulemaking in the near future to 
require use of particulate matter CEMS for compliance assurance.
    Approximately 80 percent of hazardous waste burning cement kilns 
are not currently subject to the New Source Performance Standard and 
many of these sources may not be equipped with COMS that meet 
Performance Specification 1 in appendix B, part 60. Thus, many 
hazardous waste burning cement kilns will be required to install COMS, 
even though we intend to require use of particulate matter CEMS in the 
near future. We do not believe that this requirement will be overly 
burdensome, however, because sources may request approval to install 
particulate matter CEMS rather than COMS. See Sec. 63.8(f). Our testing 
of particulate matter CEMS at a cement kiln will be completed well 
before sources need to make decisions on how best to comply with the 
COMS requirement of the rule. We will develop regulations and guidance 
on performance specifications and correlation criteria for particulate 
matter CEMS as a result of that testing, and sources can use that 
guidance to request approval to use a particulate matter CEMS in lieu 
of a COMS. We expect that most sources will elect to use this approach 
to minimize compliance costs over the long term.
    ii. Can High Correlation Runs Exceed the Particulate Matter 
Standard? The final rule states that the particulate matter and opacity 
standards of parts 60, 61, 63, 264, 265, and 266 (i.e., all applicable 
parts of Title 40) do not apply during particulate matter CEMS 
correlation testing, provided that you comply with certain provisions 
discussed below that ensure that the provision is not abused. This 
provision, as the rest of the rule, is effective immediately. Thus, you 
need not wait for the compliance date to take advantage of this 
particulate matter CEMS correlation test provision.
    We include this provision in the rule because many commenters 
question whether high correlation test runs that exceed the particulate 
matter emission standard constitute noncompliance with the standard. We 
have responded to this concern previously by stating that a single 
manual method test run that exceeds the standard does not constitute 
noncompliance with the standard because compliance is based on the 
average of a minimum of three runs.213 We now acknowledge, 
however, that during high run correlation testing a source may need to 
exceed the emission standard even after averaging emissions across 
runs. Similarly, a source may need to exceed a particulate matter 
operating parameter limit. Given the benefits of compliance assurance 
using a CEMS, we agree with commenters that short-term excursions of 
the particulate matter standard or operating parameter limits for the 
purpose of CEMS correlation testing is warranted. The benefits that a 
CEMS provides for compliance assurance outweighs the short-term 
emissions exceedances that may occur during high end emissions 
correlation testing. Consequently, we have included a conditional 
waiver of the applicability of all Federal particulate matter and 
opacity standards (and associated operating parameter limits).
---------------------------------------------------------------------------

    \213\ One exception is the destruction and removal efficiency 
standard, for which compliance is based on a single test run and not 
the average of three runs.
---------------------------------------------------------------------------

    The waiver of applicability of the particulate matter and opacity 
emission standards and associated operating parameter limits is 
conditioned on the following requirements to ensure that the waiver is 
not abused. Based on information from commenters and expertise gained 
during our testing, the rule requires that you develop and submit to 
permitting officials a particulate matter CEMS correlation test plan 
along with a statement of when and how any excess emissions will occur 
during the correlation tests (i.e., how you will modify operating 
conditions to ensure a wide range of particulate emissions, and thus a 
valid correlation test). If the permitting officials fail to respond to 
the test plan in 30 days, you can proceed with the tests as described 
in the test plan. If the permitting officials comment on the plan, you 
must address those comments and resubmit the plan for approval.
    In addition, runs that exceed any particulate matter or opacity 
emission standard or operating parameter limit are limited to no more 
than a total of 96 hours per correlation test (i.e., including all runs 
of all test conditions). We determined that the 96 hour total duration 
for exceedances for a correlation test is reasonable because it is 
comprised of one day to increase emissions to the desired level and 
reach system equilibrium, two days of testing 214 at the 
equilibrium condition followed by a return to normal equipment settings 
indicative of compliance with emissions standards and operating 
parameter limits, and one

[[Page 52930]]

day to reach equilibrium at normal conditions. Finally, to ensure these 
periods of high emissions are due to the bona fide need described here, 
a manual method test crew must be on-site and making measurements (or 
in the event some unforseen problem develops, prepared to make 
measurements) at least 24 hours after you make equipment or workplace 
modifications to increase particulate matter emissions to levels of the 
high correlation runs.
---------------------------------------------------------------------------

    \214\ The two days assumes sources will conduct a total of 18 
runs, 6 runs in each of the low, medium, and high particulate matter 
emission ranges. To approve use of a particulate matter CEMS, we 
will likely require that a minimum of 15 runs comprise a correlation 
test. If this is the case, some runs will likely be eliminated 
because they fail method or source-specific quality assurance/
quality control procedures.
---------------------------------------------------------------------------

3. What Is the Status of Total Mercury CEMS?
    We are not requiring use of total mercury CEMS in this rulemaking 
because data in hand do not adequately demonstrate nationally that 
these CEMS are reliable compliance assurance tools at all types of 
facilities. Nonetheless, we are committed to the development of CEMS 
that measure total mercury emissions and are continuing to pursue the 
development of these CEMS in our research efforts.
    In the April 1996 NPRM, we proposed that total mercury CEMS be used 
for compliance with the mercury standards. We also said if you elect to 
use a multimetals CEMS that passed proposed acceptability criteria, you 
could use that CEMS instead of a total mercury CEMS to document 
compliance with the mercury standard. Finally, we indicated that if 
neither mercury nor multimetal CEMS were required in the final rule 
(i.e., because they have not been adequately demonstrated), compliance 
assurance would be based on specified operating parameter limits.
    In the March 1997 NODA, we elicited comment on early aspects of our 
approach to demonstrate total mercury CEMS. And, in the December 1997 
NODA, we presented a summary of the demonstration test results and our 
preliminary conclusion that we were unable to adequately demonstrate 
total mercury CEMS at a cement kiln, a site judged to be a reasonable 
worst-case for performance of the total mercury CEMS. As new data are 
not available, we continue to adhere to this conclusion, and comments 
received in response to the December 1997 NODA concur with this 
conclusion. Therefore, we are not requiring total mercury CEMS in this 
rulemaking.
    Nonetheless, the current lack of data to demonstrate total mercury 
CEMS at a cement kiln or otherwise on a generic bases (i.e., for all 
sources within a category) does not mean that the technology, as 
currently developed, cannot be shown to work at particular sources. 
Consequently, the final rule provides you the option of using total 
mercury CEMS in lieu of complying with the operating parameter limits 
of Sec. 63.1209(l). As for particulate matter and other CEMS, the rule 
allows you to petition the Administrator (i.e., permitting officials) 
under Sec. 63.8(f) to use a total mercury CEMS based on documentation 
that it can meet acceptable performance specifications, correlation 
acceptance criteria (i.e., correlation coefficient, tolerance level, 
and confidence level). Although we are not promulgating the proposed 
performance specification for total mercury CEMS (Performance 
Specification 12) given that we were not able to document that a 
mercury CEMS can meet the specification in a (worst-case) cement kiln 
application, the proposed specification may be useful to you as a point 
of departure for a performance specification that you may recommend is 
achievable and reasonable.
4. What Is the Status of the Proposed Performance Specifications for 
Multimetal, Hydrochloric Acid, and Chlorine Gas CEMS?
    We are not promulgating proposed Performance Specifications 10, 13, 
and 14 for multimetal, hydrochloric acid, and chlorine gas CEMS because 
we have not determined that the CEMS can achieve the specifications.
    In the April 1996 NPRM, we proposed performance specifications for 
multimetal, hydrochloric acid, and chlorine gas CEMS to allow sources 
to use these CEMS for compliance with the metals and hydrochloric acid/
chlorine gas standards. Given that we have not demonstrated that these 
CEMS can meet their performance specifications and our experience with 
a mercury CEMS where we were not able to demonstrate that the mercury 
CEMS could meet our proposed performance specification, we are not 
certain that these CEMS can meet the proposed performance 
specifications. Accordingly, it would be inappropriate to promulgate 
them.
    As discussed previously, we encourage sources to investigate the 
use of CEMS and to petition permitting officials under Sec. 63.8(f) to 
obtain approval to use them. The proposed performance specifications 
may be useful to you as a point of departure in your efforts to 
document performance specifications that are achievable and that ensure 
reasonable correlation with reference manual methods.
5. How Have We Addressed Other Issues: Continuous Samplers as CEMS, 
Averaging Periods for CEMS, and Incentives for Using CEMS?
    a. Are Continuous Samplers a CEMS? Several commenters, mostly 
owner/operators of on-site incinerators, suggest that we should adjust 
certain CEMS criteria (e.g., averaging period, response time) to allow 
use of a continuous sampler known as the 3M Method. The 3M Method is a 
continuous metals sampling system. It automatically extracts stack gas 
and accumulates a sample on a filter medium over any desired period--24 
hours, days, or weeks. The sample is manually extracted, analyzed, and 
reported. Various incinerator operators are using or have expressed an 
interest in using this type of approach to demonstrate compliance with 
current RCRA metals emission limits. Many commenters contend that the 
3M Method is a CEMS and that we developed our performance 
specifications for CEMS to exclude techniques like the 3M Method.
    After careful analysis, we conclude that the 3M Method is not a 
CEMS. It does not meet our long-standing definition of a CEMS in parts 
60 or 63. Specifically, it is not a fully automated piece(s) of 
equipment used to extract a sample, condition and analyze the sample, 
and report the results of the analysis in the units of the standard. 
Also, the 3M Method is unable to ``complete a minimum of one cycle of 
operation (sampling, analyzing, and data recording) for each successive 
15-minute period'' as required by Sec. 63.8(c)(4)(ii). As a result, 
making the subtle changes (e.g., to the averaging period, response 
time) to our multimetal CEMS performance specification that commenters 
recommend would not alter the fact that the device does not 
automatically analyze the sample on the frequency required for a CEMS.
    A continuous sampler (coupled with periodic analysis of the sample) 
is inferior to a CEMS for two reasons. First, if the sampling period is 
longer than the time it takes to perform three manual performance 
tests, compliance with the standard cannot be assured. Approaches like 
the 3M Method tend to have reporting periods on the order of days, 
weeks, or even a month. The reporting period is comprised of the time 
required to accumulate the sample and the additional time to analyze 
the sample and report results. Because the stringency of a standard is 
a function of both the numerical value of the standard and the 
averaging period (e.g., at a given numerical limit, the longer the 
averaging period the less stringent the standard), a compliance 
approach having a sampling period greater than the 12 hours we estimate 
it may take to conduct three manual method stack test runs using Method 
29 cannot ensure

[[Page 52931]]

compliance with the standard.215 If the sampling period were 
greater than the time required to conduct three test runs, the 
numerical value of the standard would have to be reduced to ensure an 
equally stringent standard. Unfortunately, we do not know how to derive 
alternative emission limits as a function of the averaging period that 
would be equivalent to the emission standard. We raised this issue at 
proposal, and commenters did not offer a solution.
---------------------------------------------------------------------------

    \215\ A technical support document for the February 1991 
municipal waste combustor rule contains a good description of how 
not only the numerical limit, but the averaging period as well, 
determines the overall stringency of the standard. See Appendices A 
and B found in ``Municipal Waste Combustion: Background Information 
for Promulgated Standards and Guidelines--Summary of Public Comments 
and Responses Appendices A to C'', EPA-450/3-91-004, December 1990.
---------------------------------------------------------------------------

    Second, the results from a continuous sampler are reported after 
the fact, resulting in higher excess emissions than with a CEMS. 
Depending on the sample analysis frequency, it could take days or weeks 
to determine that an exceedance has occurred and that corrective 
measures need to be taken. A CEMS can provide near real-time 
information on emissions such that exceedances can be avoided or 
minimized.
    Absent the generic availability of multimetal CEMS, continuous 
samplers such as the 3M Method may nonetheless be a valuable compliance 
tool. We have acknowledged that relying on operating parameter limits 
may be an imperfect approach for compliance assurance. Sampling and 
analysis of feedstreams to determine metals feedrates can be 
problematic given the complexities of some waste matrices. In addition, 
the operating parameters for the particulate matter control device for 
which limits must be established may not always correlate well with the 
device's control efficiency for metals and thus metals emissions. 
Because of these concerns, we encourage sources to investigate the 
feasibility of multimetal CEMS. But, absent a CEMS, a continuous 
sampler may provide an attractive alternative or complement to some of 
the operating parameter limits under Secs. 63.1209 (l) and (n). You may 
petition permitting officials under Sec. 63.8(f) to use the 3M Method 
(or other sampler) as an alternative method of compliance with the 
emissions standards. Permitting officials will balance the benefits of 
a continuous sampler with the benefits of the operating parameter 
limits on a case-by-case basis.
    b. What Are the Averaging Periods for CEMS and How Are They 
Implemented? We discuss the following issues in this section: (1) 
Duration of the averaging period; (2) frequency of updating the 
averaging period; and (3) how averaging periods are calculated 
initially and under intermittent operations.
    i. What Is the Duration of the Averaging Period? We conclude that a 
six-hour averaging period is most appropriate for particulate matter 
CEMS, and a 12-hour averaging period is most appropriate for total 
mercury, multi metals, hydrogen chloride, and chlorine gas CEMS.
    We proposed that the averaging period for CEMS (i.e., other than 
carbon monoxide, hydrocarbon, and oxygen) be equivalent to the time 
required to conduct three runs of the comprehensive performance test 
using manual stack methods. As discussed above and at proposal, we 
proposed this approach because, to ensure compliance with the standard, 
the CEMS averaging period must be the same as the time required to 
conduct the performance test.216
---------------------------------------------------------------------------

    \216\ Actually, the CEMS averaging period can be no longer than 
the time required to conduct three runs of the performance test to 
ensure compliance with the standard. Although compliance with the 
standard would be ensured if the CEMS averaging period were less 
than the time required to conduct the performance test, this 
approach would be overly stringent because it would ensure 
compliance with an emission level lower than the standard.
---------------------------------------------------------------------------

    Commenters suggest two general approaches to establish averaging 
periods for CEMS: technology-based and risk-based. Commenters 
supporting a technology-based approach favor our proposed approach and 
rationale where the time duration of three emissions tests would be the 
averaging period for CEMS. Commenters favoring a risk-based approach 
state that the averaging period should be years rather than hours 
because the risk posed by emissions at levels of the standard were not 
found to be substantial, assuming years of exposure. We disagree with 
this rationale. CEMS are an option (that sources may request under 
Sec. 63.8(f)) to document compliance with the emission standard. As 
discussed above, if the averaging period for CEMS were longer than the 
duration of the comprehensive performance test, we could not ensure 
that a source maintains compliance with the standards.
    Establishing an averaging period based on the time to conduct three 
manual method stack test runs is somewhat subjective. There is no fixed 
sampling time for manual methods--sampling periods vary depending on 
the amount of time required to ``catch'' enough sample. Thus, we have 
some discretion in selecting an averaging period using this approach. 
Commenters generally favor longer averaging periods as an incentive for 
using CEMS (i.e., because a limit is less stringent if compliance is 
based on a long versus short averaging period). We agree that choosing 
a longer averaging period would provide an incentive for the use of 
CEMS, but conclude that the selected averaging period must be within 
the range (i.e., high end) of times required to perform the three stack 
test runs.
    We derive the averaging period for particulate matter CEMS as 
follows. Most particulate matter manual method tests are one hour in 
duration, but a few stack sampling companies sample for longer periods, 
up to two hours. Therefore, we use the high end of the range of values, 
2 hours, as the basis for calculating the averaging period. We 
recommend a six-hour rolling average considering that it may require 2 
hours to conduct each of three stack tests.
    For mercury, multi-metals, hydrochloric acid, and chlorine gas 
CEMS, we recommend a 12-hour rolling averaging. The data base we used 
to determine the standards shows that the sampling periods for manual 
method tests for these standards ranged from one to four hours. 
Choosing the high end of the range of values, 4 hours, as the basis for 
calculating the averaging period, we conclude that a 12-hour rolling 
average would be appropriate.
    ii. How Frequently Is the Rolling Average Updated? We conclude that 
the rolling average for particulate matter, total mercury, and 
multimetal CEMS should be updated hourly, while the rolling average for 
hydrochloric acid and chlorine gas CEMS should be updated each minute.
    We proposed that all rolling averages would be updated every minute 
and would be based on the average of the one-minute block average CEMS 
observations that occurred over the averaging period. This proposed 
one-minute update is the same that is used for carbon monoxide and 
total hydrocarbon CEMS under the RCRA BIF regulations. (We are 
retaining that update frequency in the final rule for those monitors, 
and recommend it for hydrochloric acid and chlorine gas CEMS.)
    Commenters favor selecting the frequency of updating the rolling 
average taking into account the variability of the CEMS and limitations 
concerning how the correlation data are collected. We agree with this 
approach, as discussed below.
    1. Particulate Matter CEMS. Commenters said that particulate matter 
CEMS correlation tests are approximately one hour in duration and, if 
the rolling average were updated

[[Page 52932]]

each minute, the CEMS would observe more variability in emissions 
within this one hour than the manual method (which is an average of 
those emissions during the hour). For this reason, we conclude it is 
reasonable that particulate matter CEMS data be recorded as a block-
hour and that the rolling average be updated every hour as the average 
of the previous six block-hours. Updating the particulate matter CEMS 
every hour also means the number of compliance opportunities is the 
same irrespective of whether a light-scattering or beta-gage 
particulate matter CEMS is used (i.e., because beta-gage CEMS make 
observations periodically while light-scattering CEMS make observations 
continuously).
    Furthermore, to ensure consistency with existing air rules 
governing CEMS other than opacity, a valid hour should be comprised of 
four or more equally spaced measurements during the hour. See 
Sec. 60.13(h). This means that batch systems, such as beta gages, must 
complete one cycle of operation every 15 minutes, or more frequently if 
possible. See Sec. 63.8(c)(4)(ii). CEMS that produce a continuous 
stream of data, such as light-scattering CEMS, will produce data 
throughout the hour.
    You may not be able to have four valid 15-minute measurement in an 
hour, however, to calculate an hourly block-average. Examples include 
when the source shuts down or the CEMS produces flagged (i.e., 
problematic) data. In addressing this issue, we balanced the need for 
the average of the measurements taken during the hour to be 
representative of emissions during the hour with the need to 
accommodate problems with data availability that will develop. We 
conclude that a particulate matter CEMS needs to sample stack gas and 
produce a valid result from this sample for most of the hour. This 
means that the CEMS needs to be observing stack gas at least half (30 
minutes, or two 15-minute cycles of operation) of the block-hour. 
Emissions from less than one hour might be unrepresentative of 
emissions during the hour, and on balance we conclude that this 
approach is reasonable. If a particulate matter CEMS does not sample 
stack gas and produce a valid result from that sample for at least 30 
minutes of a given hour, the hour is not a valid block-hour. In 
documenting compliance with the data availability recommendation in the 
draft performance specification, invalid block-hours due to 
unavailability of the CEMS that occur when the source is in operation 
count against data availability. If the hour is not valid because the 
source was not operating for more than 30 minutes of the hour, however, 
the invalid block-hour does not count against the data availability 
recommendation.217
---------------------------------------------------------------------------

    \217\ Data availability is defined as the fraction, expressed as 
a percentage, of the number of block-hours the CEMS is operational 
and obtaining valid data during facility operations, divided by the 
number of block-hours the facility was operating.
---------------------------------------------------------------------------

    2. Total Mercury and Multimetal CEMS. As discussed for particulate 
matter CEMS, we also expect manual methods will be required to 
correlate total mercury and multimetal CEMS prior to using them for 
compliance. For the reasons discussed above in the context of 
particulate matter CEMS, we therefore recommend the observations from 
these CEMS be recorded as block-hour averages and that the 12-hour 
rolling average be updated every hour based on the average of the 
previous 12 block-hour averages.
    3. Hydrochloric Acid and Chlorine Gas CEMS. Unlike the particulate 
matter, total mercury, and multimetal CEMS, hydrochloric acid and 
chlorine gas CEMS are likely to be calibrated using Protocol 1 gas 
bottles rather than correlated to manual method stack test results. 
Therefore, the variability of observations measured by the CEMS over 
some averaging period versus the duration of a stack test is not an 
issue. We conclude that it is appropriate to update the 12-hour rolling 
average for these CEMS every minute, as required for carbon monoxide 
and hydrocarbons CEMS.
    iii. How Are Averaging Periods Calculated Initially and under 
Intermittent Operations?
    1. Practical Effective Date of Rolling Averages for CEMS. As 
discussed in Part Five, Sections VII.B.4 above in the context of 
continuous monitoring systems in general, CEMS recordings will not 
become effective for compliance monitoring on the compliance date until 
you have recorded enough observations to calculate the rolling average 
applicable to the CEMS. For example, the six hourly rolling average for 
particulate matter CEMS does not become effective until you have 
recorded six block-hours of observations on the compliance date. Given 
that compliance with the standards begins nominally at 12:01 am on the 
compliance date, the six hour rolling average for particulate matter 
CEMS does not become effective as a practical matter until 6:01 am on 
the compliance date. Similarly, the 12-hour rolling average for a 
multimetal CEMS does not become effective until you have recorded 12 
block-hours of observations after the compliance date. Thus, the 12-
hour rolling average for multimetals CEMS becomes effective as a 
practical matter at 12:01 p.m. on the compliance date.
    We adopt this approach simply because a rolling average does not 
exist until enough observations have been recorded to calculate the 
rolling average.
    2. How Rolling Averages Are Calculated Upon Intermittent 
Operations. We have determined that you are to ignore periods of time 
when CEMS observations are not recorded for any reason (e.g., source 
shutdown) when calculating rolling averages. For example, consider how 
the six hour rolling average for a particulate matter CEMS would be 
calculated if a source shuts down for yearly maintenance for a three 
week period. The first one-hour block average value recorded when the 
source renews operations is added to the last 5 one-hour block averages 
recorded before the source shut down for maintenance to calculate the 
six hour rolling average.
    We adopt this approach for all continuous monitoring systems, 
including CEMS, because it is simple and reasonable. See discussion in 
Part Five, Section B.4 above.
    c. What Are the Incentives for Using CEMS as Alternative 
Monitoring? We strongly support the use of CEMS for compliance with 
standards, even though we are not requiring their use in today's rule 
(except for carbon monoxide, hydrocarbon, and oxygen CEMS) for the 
reasons discussed above. We endorse the principle that, as technology 
advances, current rules should not act as an obstacle to adopting new 
CEMS technologies for compliance. For instance, today's rule does not 
require total mercury CEMS because implementation and demonstration 
obstacles observed during our tests under what we consider worst-case 
conditions (i.e., a cement kiln) could not be resolved in sufficient 
time to require total mercury CEMS at all hazardous waste combustors. 
However, we fully expect total mercury CEMS will improve to the point 
that the technical issues encountered in our tests can be resolved. At 
that point, we do not want the compliance regime of today's rule--
comprised of emissions testing and limits on operating parameters--to 
be so rigid as to preclude the use of CEMS. Commenters are generally 
supportive of this concept, but note that facilities would be reluctant 
to adopt new technologies without adequate incentives. This section 
describes potential incentives: emissions testing would not be 
required; limits on operating parameters would not apply while the CEMS 
is in service; and the feedstream analysis requirements for the

[[Page 52933]]

parameters measured by the CEMS (i.e., metals or chlorine) would not 
apply.
    i. What Incentives Do Commenters Suggest? Several commenters 
suggest that we provide various incentives to encourage development and 
implementation of new and emerging CEMS. Comments by the Coalition for 
Responsible Waste Incineration (CRWI) include a variety of actions to 
encourage voluntary installation of CEMS,218 including: 
Reduce testing for any parameter measured by a CEMS to the correlation 
and maintenance of that CEMS; waive operating parameter limits that are 
linked to the pollutant measured by the CEMS; minimize regulatory 
oversight on waste analysis if compliance is consistently demonstrated 
by a CEMS; increase the emission limit for a source using a CEMS to 
account for the uncertainty of CEMS observations; allow a phase-in 
period when a source can evaluate CEMS performance and develop 
maintenance practices and the CEMS would not be used for compliance; 
allow a phase-in period to establish a reasonable availability 
requirement for that CEMS at a particular location; and allow sources 
to evaluate CEMS on a trial basis to determine if these instruments are 
appropriate for their operations with no penalties if the units do not 
work or have excessive downtime. Many of CRWI's suggestions have merit, 
as discussed below.
---------------------------------------------------------------------------

    \218\ By ``optional use of CEMS'', we mean using CEM not 
required by this rule, i.e., other than those for carbon monoxide, 
oxygen, and hydrocarbon.
---------------------------------------------------------------------------

    ii. How Do We Respond to Commenter's Recommended Incentives?
    1. Waiver of Emissions Testing and Operating Parameter Limits. 
CRWI's first two suggestions (reduced testing and waiver of operating 
parameter limits) are closely linked. The purpose of conducting a 
comprehensive performance test is to document compliance with emission 
standard initially (and periodically thereafter) and establish limits 
on specified operating parameters to ensure that compliance is 
maintained. Because a CEMS ensures compliance continuously, it serves 
the purpose of both the performance test and compliance with operating 
parameter limits. Accordingly, we agree with CRWI that both emissions 
testing and operating parameter limits for the pollutant in question 
would not apply to sources using a CEMS.
    There is one key caveat to this position, however. Because 100% 
availability of any CEMS is unrealistic, we require a means of assuring 
compliance with the emission standards during periods when the CEMS is 
not available. To meet that need, you may elect to install redundant 
CEMS or assure continuous compliance by monitoring and recording 
traditional operating parameter limits during periods when the CEMS is 
not available. Most likely, you will elect to use operating parameters 
as the back-up when the CEMS is unavailable because it would be a less 
expensive approach. You could establish these operating parameter 
limits, though, through CEMS measurements rather than comprehensive 
performance test measures. In fact, it may be prudent for you to 
evaluate relationships between various operating parameters for the 
particulate matter control device 219 and emission levels 
recorded by the CEMS to develop a good predictive model of emissions. 
You could then petition the Administrator (i.e., permitting officials) 
under Sec. 63.8(f) to base compliance during CEMS malfunctions on 
limits on alternative monitoring parameters derived from the predictive 
model.
---------------------------------------------------------------------------

    \219\ You are not restricted to those specified in Sec. 63.1209. 
You may identify parameters for your source that correlate better 
with particulate emissions than those we have specified generically.
---------------------------------------------------------------------------

    2. Waiver of Feedstream Analysis Requirements. If you obtain 
approval to use a CEMS for compliance under the petitioning provisions 
of Sec. 63.8(f), we agree with the commenter's recommendation that you 
should not be subject to the feedstream analysis requirements pertinent 
to the pollutant you are measuring with a CEMS. As examples, if you use 
a total mercury CEMS, you are not subject to a feedrate limit for 
mercury, and if you operate an incinerator and use a particulate matter 
CEMS, you are not subject to a feedrate limit for total ash.
    If you are not subject to a feedrate limit for ash, metals, or 
chorine because you use a CEMS for compliance, you are not subject to 
the feedstream analysis requirements for these materials. As a 
practical matter, however, this waiver may be moot because, as 
discussed above, you will probably elect to comply with operating 
parameter limits during CEMS malfunctions. However, a second, back-up 
CEMS would also be acceptable. Absent a second CEMS, you would need to 
establish feedrate limits for these materials as a back-up compliance 
approach, and you would need to know the feedrate at any time given 
that the CEMS may malfunction at any time. In addition, even when the 
CEMS is operating within the performance specifications approved by the 
permitting officials, you have the responsibility to minimize 
exceedances by, for example, characterizing your feedstreams adequately 
to enable you to take corrective measures if a CEMS-monitored emission 
is approaching the standard. This level of feedstream characterization, 
however, is less than the characterization required to establish and 
comply with feedrate operating limits during CEMS malfunctions or 
absent a CEMS.
    3. Increase the Averaging Period for CEMS-Monitored Pollutants. The 
averaging period for a CEMS-monitored pollutant should not be 
artificially inflated (i.e., increased beyond the time required to 
conduct three manual method test runs) because the standard would be 
less stringent. See previous discussions on this issue.
    4. Increase Emission Limits to Account for CEMS Uncertainty. We do 
not agree with the suggestion that an emission limit needs to be 
increased on a site-specific basis to accommodate CEMS inaccuracy and 
imprecision (i.e., the acceptance criteria in the CEMS performance 
specification that the source recommends and the permitting officials 
approve will necessarily allow some inaccuracy and imprecision). Again, 
we encourage sources to use a CEMS because it is a better indicator of 
compliance than the promulgated compliance regime (i.e., periodic 
emissions testing and operating parameter limits). We established the 
final emission standards with achievability (through the use of the 
prescribed compliance methods) in mind. We have accounted for the 
inaccuracies and imprecisions in the emissions data in the process of 
establishing the standard. See previous discussions in Part Four, 
Section V.D. If the CEMS performance specification acceptance criteria 
(that must be approved by permitting officials under a Sec. 63.8(f) 
petition) were to allow the CEMS measurements to be more inaccurate or 
imprecise than the promulgated compliance regime of performance testing 
coupled with limits on operating parameters, the potential for improved 
compliance assurance with the CEMS would be negated. Consequently, we 
reject the idea that the standards need to be increased on a site-
specific basis as an incentive for sources to use CEMS.
    5. Allow a CEMS Phase-In Period. CRWI's final three incentive 
suggestions deal with the need for a CEMS phase-in period. This phase-
in period would be used to evaluate CEMS performance, including 
identifying acceptable performance specification levels, maintenance 
requirements, and measurement location. CRWI further suggested that the 
Agency not penalize

[[Page 52934]]

a source if the CEMS does not work or has excessive downtime.
    CRWI provided these comments in response to our proposal to require 
compliance using CEMS and that sources document that the CEMS meets a 
prescribed performance specification and correlation acceptance 
criteria. Although we agree that a phase-in period would be 
appropriate, the issue is moot given that we are not requiring the use 
of CEMS.220 Prior to submitting a petition under 
Sec. 63.8(f) to gain approval to use a CEMS, we presume a source will 
identify the performance specification, correlation criteria, and 
availability factors they believe are achievable. (We expect sources to 
use the criteria we have proposed, as revised after considering 
comments and further analysis and provided through guidance, as a point 
of departure.) Thus, each source will have unlimited opportunity to 
phase-in CEMS and subsequently recommend under Sec. 63.8(f) performance 
specifications and correlation acceptance criteria.
---------------------------------------------------------------------------

    \220\ Other than carbon monoxide, hydrocarbon, and oxygen CEMS.
---------------------------------------------------------------------------

    We do not agree as a legal matter that we can state generically 
that CEMS data obtained during the demonstration period are shielded 
from enforcement if the CEMS data are credible and were to indicate 
exceedance of an emission standard. In this situation, we cannot shield 
a source from action by either by a regulatory agency or a citizen 
suit. On balance, given our legal constraints, our policy desire to 
have CEMS used for compliance, and uncertainty about the ultimate 
accuracy of the CEMS data, we can use our enforcement discretion 
whether to use particulate matter CEMS data as credible evidence in the 
event the CEMS indicates an exceedance until the time the CEMS is 
formally adopted as a compliance tool. Sources and regulators may 
decide to draft a formal testing agreement that states that the CEMS 
data obtained prior to the time the CEMS is accepted as a compliance 
tool cannot be used as credible evidence of exceedance of an emission 
standard.
D. What Are the Compliance Monitoring Requirements?
    In this section we discuss the operating parameter limits that 
ensure compliance with each emission standard.
1. What Are the Operating Parameter Limits for Dioxin/Furan?
    You must maintain compliance with the dioxin/furan emission 
standard by establishing and complying with limits on operating 
parameters. See Sec. 63.1209(k). The following table summarizes these 
operating parameter limits. All sources must comply with the operating 
parameter limits applicable to good combustion practices. Other 
operating parameter limits apply if you use the dioxin/furan control 
technique to which they apply.

BILLING CODE 6560-50-P

[[Page 52935]]

[GRAPHIC] [TIFF OMITTED] TR30SE99.000



[[Page 52936]]

[GRAPHIC] [TIFF OMITTED] TR30SE99.001



BILLING CODE 6560-50-C

[[Page 52937]]

    Dioxin/furan emissions from hazardous waste combustors are 
primarily attributable to surface-catalyzed formation reactions 
downstream from the combustion chamber when gas temperatures are in the 
450  deg.F to 650  deg.F window (e.g., in an electrostatic precipitator 
or fabric filter; in extensive ductwork between the exit of a 
lightweight aggregate kiln and the inlet to the fabric filter; as 
combustion gas passes through an incinerator waste heat recovery 
boiler). In addition, dioxin/furan partition in two phases in stack 
emissions: a portion is adsorbed onto particulate matter and a portion 
is emitted as a vapor (gas). Because of these factors, and absent a 
CEMS for dioxin/furan, we are requiring a combination of approaches to 
control dioxin/furan emissions: (1) Temperature control at the inlet to 
a dry particulate matter control device to limit dioxin/furan formation 
in the control device; (2) operation under good combustion conditions 
to minimize dioxin/furan precursors and dioxin/furan formation during 
combustion; and (3) compliance with operating parameter limits on 
dioxin/furan emission control equipment (e.g., carbon injection) that 
you may elect to use.
    We discuss below the operating parameter limits that apply to each 
dioxin/furan control technique.
    a. Combustion Gas Temperature Quench. To minimize dioxin/furan 
formation in a dry particulate matter control device that suspends 
collected particulate matter in the gas flow (e.g., electrostatic 
precipitator, fabric filter), the rule limits the gas temperature at 
the inlet to these control devices 221 to levels occurring 
during the comprehensive performance test. For lightweight aggregate 
kilns, however, you must monitor the gas temperature at the kiln exit 
rather than at the inlet to the particulate matter control device. This 
is because the dioxin/furan emission standard for lightweight aggregate 
kilns specifies rapid quench of combustion gas to 400  deg.F or less at 
the kiln exit. 222
---------------------------------------------------------------------------

    \221\ The temperature at the inlet to a cyclone separator used 
as a prefiltering process for removing larger particles is not 
limited. Cyclones do not suspend collected particulate matter in the 
gas stream. Thus, these devices do not have the same potential to 
enhance dioxin/furan formation as electrostatic precipitators and 
fabric filters.
    \222\ As discussed in Part Four, Section VIII, lightweight 
aggregate kilns can have extensive ducting between the kiln exit and 
the inlet to the fabric filter. If gas temperatures are limited at 
the inlet to the fabric filter, substantial dioxin/furan formation 
could occur in the ducting.
---------------------------------------------------------------------------

    If your combustor is equipped with a wet scrubber as the initial 
particulate matter control device, you are not required to establish 
limits on combustion gas temperature at the scrubber. This is because 
wet scrubbers do not suspend collected particulate matter in the gas 
stream and gas temperatures are well below 400  deg.F in the 
scrubber.223 Thus, scrubbers do not enhance surface-
catalyzed formation reactions.
---------------------------------------------------------------------------

    \223\ For this reason, you are not required to document during 
the comprehensive performance test that gas temperatures in the wet 
scrubber are not greater than 400  deg.F. Also, we note that the 400 
 deg.F temperature limit of the dioxin/furan standard does not apply 
to wet scrubbers, but rather to the inlet to a dry particulate 
matter control device and the kiln exit of a lightweight aggregate 
kiln.
---------------------------------------------------------------------------

    We proposed limits on the gas temperature at the inlet to a dry 
particulate matter control device (see 61 FR at 17424). Temperature 
control at this location is important because surface-catalyzed 
formation reactions can increase by a factor of 10 for every 150  deg.F 
increase in temperature within the window of 350  deg.F to 
approximately 700  deg.F. We received no adverse comments on the 
proposal, and thus, are adopting this compliance requirement in the 
final rule.
    You must establish an hourly rolling average temperature limit 
based on operations during the comprehensive performance test. The 
hourly rolling average limit is established as the average of the test 
run averages. See Part Five, Sections VII.B.1 and B.3 above for a 
discussion on the approach for calculating limits from comprehensive 
performance test data.
    b. Good Combustion Practices. All hazardous waste combustors must 
use good combustion practices to control dioxin/furan emissions by: (1) 
Destroying dioxin/furan that may be present in feedstreams; (2) 
minimizing formation of dioxin/furan during combustion; and (3) 
minimizing dioxin/furan precursor that could enhance post-combustion 
formation reactions. As proposed, you must establish and continuously 
monitor limits on three key operating parameters that affect good 
combustion: (1) Maximum hazardous waste feedrate; (2) minimum 
temperature at the exit of each combustion chamber; and (3) residence 
time in the combustion chamber as indicated by gas flowrate or kiln 
production rate. We have also determined that you must establish 
appropriate monitoring requirements to ensure that the operation of 
each hazardous waste firing system is maintained. We discuss each of 
these parameters below.
    i. Maximum Hazardous Waste Feedrate. You must establish and 
continuously monitor a maximum hazardous waste feedrate limit for 
pumpable and nonpumpable wastes. See 61 FR at 17422. An increase in 
waste feedrate without a corresponding increase in combustion air can 
cause inefficient combustion that may produce (or incompletely destroy) 
dioxin/furan precursors. You must also establish hazardous waste 
feedrate limits for each location where waste is fed.
    One commenter suggests that there is no reason to limit the 
feedrate of each feedstream; a limit on the total hazardous waste 
feedrate to each combustion chamber would be a more appropriate control 
parameter. We concur in part. Limits are not established for each 
feedstream. Rather, limits apply to total and pumpable wastes feedrates 
for each feed location. Limits on pumpable wastes are needed because 
the physical form of the waste can affect the rate of oxygen demand and 
thus combustion efficiency. Pumpable wastes often will expose a greater 
surface area per mass of waste than nonpumpable wastes, thus creating a 
more rapid oxygen demand. If that demand is not satisfied, inefficient 
combustion will occur. We also note that these waste feedrate limit 
requirements are consistent with current RCRA permitting requirements 
for hazardous waste combustors.
    As proposed, you must establish hourly rolling average limits for 
hazardous waste feedrate from comprehensive performance test data as 
the average of the highest hourly rolling averages for each run. See 
Part Five, Section VII.B.3 above for the rationale for this approach 
for calculating limits from comprehensive performance test data.
    ii. Minimum Gas Temperature in the Combustion Zone. You must 
establish and continuously monitor limits on minimum gas temperature in 
the combustion zone of each combustion chamber irrespective of whether 
hazardous waste is fed into the chamber. See 61 FR at 17422. These 
limits are needed because, as combustion zone temperatures decrease, 
combustion efficiency can decrease resulting in increased formation of 
(or incomplete destruction of) dioxin/furan precursors.224
---------------------------------------------------------------------------

    \224\ See USEPA, ``Final Technical Support Document for 
Hazardous Waste Combustor MACT Standards, Volume IV: Compliance with 
the Hazardous Waste Combustor Standards'', February, 1999.
---------------------------------------------------------------------------

    Monitoring combustion zone temperatures can be problematic, 
however, because the actual burning zone temperature cannot be measured 
at many units (e.g., cement kilns). For this reason, the BIF rule 
requires

[[Page 52938]]

measurement of the ``combustion chamber temperature where the 
temperature measurement is as close to the combustion zone as 
possible.'' See Sec. 266.103(c)(1)(vii). In some cases, temperature is 
measured at a location quite removed from the combustion zone due to 
extreme temperatures and the harsh conditions at the combustion zone. 
We discussed this issue at proposal and indicated that we were 
concerned that monitoring at such remote locations may not accurately 
reflect changes in combustion zone temperatures. See 61 FR at 17423.
    We requested comment on possible options to address the issue. 
Under one option, the final rule would have allowed the source to 
identify a parameter that correlates with combustion zone temperature 
and to provide data or information to support the use of that parameter 
in the operating record. Under another option, the final rule would 
have enabled regulatory officials on a case-specific basis to require 
the use of alternate parameters as deemed appropriate, or to determine 
that there is no practicable approach to ensure that minimum combustion 
chamber temperature is maintained (and what the recourse/consequence 
would be).
    Some commenters recommend the status quo as identified by the BIF 
rule requirements for monitoring combustion zone temperature. These 
commenters suggest that more prescriptive requirements would not be 
implementable for cement kilns because use of the temperature 
measurement instrumentation would simply not be practicable under 
combustion zone conditions in a cement kiln. We agree that combustion 
zone temperature monitoring for certain types of sources requires some 
site-specific considerations (as evidenced in our second proposed 
option discussed above), and conclude that more specific language than 
that used in the BIF rule to address this issue would not be 
appropriate. Accordingly, we adopt language similar to the BIF rule in 
today's final rule. You must measure the temperature of each combustion 
chamber at a location that best represents, as practicable, the bulk 
gas temperature in the combustion zone of that chamber. You are 
required to identify the temperature measurement location and method in 
the comprehensive performance test plan, which is subject to Agency 
approval.
    The temperature limit(s) apply to each combustion zone, as 
proposed. See 61 FR at 17423. For incinerators with a primary and 
secondary chamber, you must establish separate limits for the 
combustion zone in each chamber.225 For kilns, you must 
establish separate temperature limits at each location where hazardous 
waste may be fired (e.g., the hot end where clinker is discharged; and 
the upper end of the kiln where raw material is fed). We also proposed 
to include temperature limits for hazardous waste fired at the midkiln. 
One commenter indicates that it is technically infeasible to measure 
temperature directly at the midkiln waste feeding location, however. We 
agree that midkiln gas temperature is difficult to measure due to the 
rotation of the kiln.226 Thus, the final rule allows 
temperature measurement at the kiln back-end as a surrogate.
---------------------------------------------------------------------------

    \225\ The temperature limits apply to a combustion chamber even 
if hazardous waste is not burned in the chamber for two reasons. 
First, an incinerator may rely on an afterburner that is fired with 
a fuel other than hazardous waste to ensure good combustion of 
organic compounds volatilized from hazardous waste in the primary 
chamber. Second, MACT controls apply to total emissions (except 
where the rule makes specific provisions), irrespective of whether 
they derive from burning hazardous waste or other material, or from 
raw materials.
    \226\ See USEPA. ``Final Technical Support Document for 
Hazardous Waste Combustor MACT Standards, Volume IV: Compliance with 
the Hazardous Waste Combustor Standards'', February, 1999, for 
further discussion.
---------------------------------------------------------------------------

    You must establish an hourly rolling average temperature limit 
based on operations during the comprehensive performance test. The 
hourly rolling average limit is established as the average of the test 
run averages. See Part Five, Sections VII.B.1 and B.3 above for a 
discussion on the approach for calculating limits from comprehensive 
performance test data.
    iii. Maximum Flue Gas Rate or Kiln Production Rate. As proposed, 
you must establish and continuously monitor a limit on maximum flue gas 
flowrate or, as a surrogate, kiln production rate. See 61 FR at 17423. 
Flue gas flowrates in excess of those that occur during comprehensive 
performance testing reduce the time that combustion gases are exposed 
to combustion chamber temperatures. Thus, combustion efficiency can 
decrease potentially causing an increase in dioxin/furan precursors 
and, ultimately, dioxin/furan emissions.227
---------------------------------------------------------------------------

    \227\ We note that an increase in gas flowrate can also 
adversely affect the performance of a dioxin/furan emission control 
device (e.g., carbon injection, catalytic oxidizer). Thus, gas 
flowrate is controlled for this reason as well.
---------------------------------------------------------------------------

    For cement kilns and lightweight aggregate kilns, the rule allows 
the use of production rate as a surrogate for flue gas flowrate. This 
is the approach currently used for the BIF rule for these devices, 
given that flue gas flowrate correlates with production rate (e.g., 
feedrate of raw materials or rate of production of clinker or 
aggregate).
    At proposal, however, we expressed concern that production rate may 
not relate well to flue gas flowrate in situations where the moisture 
content of the feed to the combustor changes dramatically. See 61 FR at 
17423. Some commenters concur and also express concern that production 
rate is not a reliable surrogate for flue gas flowrate because changes 
in ambient temperature can cause increased heat rates and changes in 
operating conditions can result in variability in excess air rates. 
Based on an analysis of kiln processes, however, we conclude that these 
issues should not be a concern. With respect to changes in moisture 
content of the feed, kilns tend to have a steady and homogeneous waste 
and raw material processing system. Thus, the feed moisture content 
does not fluctuate widely, and variation in moisture content of the 
stack does not significantly affect gas flowrate.228 Thus, 
production rate should be an adequate surrogate for gas flowrate for 
our purposes here.
---------------------------------------------------------------------------

    \228\ See USEPA, ``Final TSD for hazardous Waste Combustor MACT 
Standards, Volume IV: Compliance with the Hazardous Waste Combustor 
Standards'', February, 1999 for further discussion.
---------------------------------------------------------------------------

    You must establish a maximum gas flowrate or production rate limit 
as the average of the maximum hourly rolling averages for each run of 
the comprehensive performance test. See Part Five, Sections VII.B.3 
above for the rationale for the approach for calculating limits from 
comprehensive performance test data.
    iv. Operation of Each Hazardous Waste Firing System. You must 
recommend in the comprehensive performance test plan that you submit 
for review and approval operating parameters, limits, and monitoring 
approaches to ensure that each hazardous waste firing system continues 
to operate as efficiently as demonstrated during the comprehensive 
performance test.
    It is important to maintain operation of the hazardous waste firing 
system at levels of the performance test to ensure that the same or 
greater surface area of the waste is exposed to combustion conditions 
(e.g., temperature and oxygen). Oxidation takes place more quickly and 
completely as the surface area per unit of mass of the waste increases. 
If the firing system were to degrade over time such that smaller 
surface area is exposed to combustion conditions, inefficient 
combustion could result leading potentially to an increase in dioxin/
furan precursors.

[[Page 52939]]

    At proposal, we discussed establishing operating parameter limits 
only for minimum nozzle pressure and maximum viscosity of wastes fired 
using a liquid waste injection system. In developing the final rule, 
however, we determined that RCRA permit writers currently establish 
operating parameter limits on each waste firing system to ensure 
compliance with the RCRA destruction and removal efficiency (DRE) 
standard. We are continuing the DRE requirement as a MACT standard, and 
as discussed in Section VII.D.7 below, the DRE operating parameter 
limits are identical to those required to maintain good combustion 
practices for compliance with the dioxin/furan standard. This is 
because compliance with the DRE standard is ensured by maintaining good 
combustion practices. Consequently, we include a requirement to 
establish limits on operating parameters for each waste or fuel firing 
system as a measure of good combustion practices for the dioxin/furan 
standard as well to be technically correct and for purposes of 
completeness.229 Because this requirement is identical to an 
existing RCRA requirement, it will not impose an incremental burden.
---------------------------------------------------------------------------

    \229\ Because incomplete combustion of fuels (e.g., oil, coal, 
tires) could contribute to increased dioxin/furan emissions by 
producing dioxin/furan precursors, permitting official may require 
(during review and approval of the comprehensive performance test 
plan) that you establish limits on operating parameters for firing 
systems in addition to those firing hazardous waste.
---------------------------------------------------------------------------

    The rule does not prescribe generic operating parameters and how to 
identify limits because, given the variety of firing systems and waste 
and fuel properties, they are better defined on a site-specific basis. 
Examples of monitoring parameters for a liquid waste firing system 
would be, as proposed, minimum nozzle pressure established as an hourly 
rolling average based on the average of the minimum hourly rolling 
averages for each run, coupled with a limit on maximum waste viscosity. 
The viscosity limit could be monitored periodically based on sampling 
and analysis. Examples of monitoring parameters for a lance firing 
system for sludges could be minimum pressure established as discussed 
above, plus a limit on the solids content of the waste.
    v. Consideration of Restrictions on Batch Size, Feeding Frequency, 
and Minimum Oxygen Concentration. We proposed site-specific limits on 
maximum batch size, batch feeding frequency, and minimum combustion gas 
oxygen concentration as additional compliance requirements to ensure 
good combustion practices. See 61 FR at 17423. After carefully 
considering all comments, and for the reasons discussed below, we 
conclude that the carbon monoxide and hydrocarbon emission standards 
assure use of good combustion practices during batch feed operations. 
This is because the carbon monoxide and hydrocarbon CEMS are reliable 
and continuous indicators of combustion efficiency. In situations where 
batch feed operating requirements may be needed to better assure good 
combustion practices, however, we rely on the permit writer's 
discretionary authority under Sec. 63.1209(g)(2) to impose additional 
operating parameter limits on a site-specific basis.
    Many hazardous waste combustors burn waste fuel in batches, such as 
metal drums or plastic containers. Some containerized waste can 
volatilize rapidly, causing a momentary oxygen-deficient condition that 
can result in an increase in emissions of carbon monoxide, hydrocarbon, 
and dioxin/furan precursors. We proposed to limit batch size, batch 
feeding frequency, and minimum combustion gas oxygen concentration to 
address this concern.
    Commenters suggest that the proposed batch feed requirements (that 
would limit operations to the smallest batch, the longest time 
interval, and the maximum oxygen concentration demonstrated during the 
comprehensive performance test) would result in extremely conservative 
limits that would severely limit a source's ability to batch-feed 
waste. Given these concerns and our reanalysis of the need for these 
limits, we conclude that the carbon monoxide and hydrocarbon emission 
standards will effectively ensure good combustion practices for most 
batch feed operations. Consequently, the final rule does not require 
limits for batch feed operating parameters.
    Carbon monoxide or hydrocarbon monitoring may not be adequate for 
all batch feed operations, however, to ensure good combustion practices 
are maintained. We anticipate that permitting officials will determine 
on a site-specific basis, typically during review of the initial 
comprehensive performance test plan, whether limits on one or more 
batch feed operating parameters need to be established to ensure good 
combustion practices are maintained. This review should consider your 
previous compliance history (e.g., frequency of automatic waste feed 
cutoffs attributable to batch feed operations that resulted in an 
exceedance of an operating limit or standard under RCRA regulations 
prior to the compliance date), together with the design and operating 
features of the combustor. Providing permitting officials the authority 
under Sec. 63.1209(g)(2) to establish batch feed operating parameter 
limits only where warranted precludes the need to impose the limits on 
all sources.
    Permitting officials may also determine that limits on batch feed 
operating parameters are needed for a particular source based on the 
frequency of automatic waste feed cutoffs after the MACT compliance 
date. Permitting officials would consider cutoffs that are attributable 
to batch feed operations and that result in an exceedance of an 
operating parameter limit or the carbon monoxide or hydrocarbon 
emission standard. Given that you must notify permitting officials if 
you have 10 or more automatic waste feed cutoffs in a 60-day period 
that result in an exceedance of an operating parameter limit or CEMS-
monitored emission standard, permitting officials should take the 
opportunity to determine if batch feed operations contributed to the 
frequency of exceedances. If so, permitting officials should use the 
authority under Sec. 63.1209(g)(2) to establish batch feed operating 
parameter limits.
    Although we are not finalizing batch feed operating parameter 
limits, we anticipate that permitting officials will require you 
(during review and approval of the test plan) to simulate worst-case 
batch feed operating conditions during the comprehensive performance 
test when demonstrating compliance with the dioxin/furan and 
destruction and removal efficiency standards. It would be inappropriate 
for you to operate your batch feed system during the comprehensive 
performance test in a manner that is not considered worst-case, 
considering the types and quantities of wastes you may burn, and the 
range of values you may encounter during operations for batch feed-
related operating parameters (e.g., oxygen levels, batch size and/or 
btu content, waste volatility, batch feeding frequency).
    To ensure that the CEMS-monitored carbon monoxide and hydrocarbon 
emission standards ensure good combustion practices for batch feed 
operations, the final rule includes special requirements to ensure that 
``out-of-span'' carbon monoxide and hydrocarbon CEMS readings are 
adequately accounted for. We proposed batch feed operating parameter 
limits in part because of concern that the carbon monoxide and 
hydrocarbon CEMS may not accurately calculate hourly rolling averages 
when you encounter emission concentrations that exceed the span of the 
CEMS. This is an important

[[Page 52940]]

consideration because batch feed operations have the potential to 
generate large carbon monoxide or hydrocarbon spikes--large enough at 
times to exceed the span of the detector. When this occurs, the CEMS in 
effect ``pegs out'' and the analyzer may only record data at the upper 
end of its span, while in fact carbon monoxide/hydrocarbon 
concentrations are much higher. In these situations, the true carbon 
monoxide/hydrocarbon concentration is not being used to calculate the 
hourly rolling average. This has two significant consequences of 
concern to us.230
---------------------------------------------------------------------------

    \230\ As explained in Part Five, Section VII.D.4 of the text, 
this concern is not limited to batch feed operations.
---------------------------------------------------------------------------

    First, you could experience a large carbon monoxide/hydrocarbon 
spike (as a result of feeding a large or highly volatile batch) which 
causes the monitor to ``peg out.'' In this situation, the CEMS would 
record carbon monoxide/hydrocarbon levels that are lower than actual 
levels. This under-reporting of emission levels would result in an 
hourly rolling average that is biased low. You may in fact be exceeding 
the emission standard even though the CEMS indicates you are in 
compliance. Second, if a carbon monoxide/hydrocarbon excursion causes 
an automatic waste feed cutoff, you may be allowed to resume hazardous 
waste burning much sooner than you would be allowed if the CEMS were 
measuring true hourly rolling averages. This is because you must 
continue monitoring operating parameter limits and CEMS-monitored 
emission standards after an automatic waste feed cutoff and you may not 
restart hazardous waste feeding until all limits and CEMS-monitored 
emission standards are within permissible levels.231
---------------------------------------------------------------------------

    \231\ A higher hourly rolling average carbon monoxide level that 
is above the standard requires a longer period of time to drop below 
the standard.
---------------------------------------------------------------------------

    As explained in Part Five, Section VII.D.4 below, we have resolved 
these ``out of span'' concerns by including special provisions in 
today's rule for instances when you encounter hydrocarbon/carbon 
monoxide CEMS measurements that are above the upper span required by 
the performance specifications.232 These special provisions 
require you to assume hydrocarbons and carbon monoxide are being 
emitted at levels of 500 ppmv and 10,000 ppmv, respectively, when any 
one minute average exceeds the upper span level of the 
detector.233 Although we did not propose these special 
provisions, they are a logical outgrowth of the proposed batch feed 
requirements and commenters concerns about those requirements.
---------------------------------------------------------------------------

    \232\ The carbon monoxide CEMS upper span level for the high 
range is 3000 ppmv. The upper span level for hydrocarbon CEMS is 100 
ppmv. (See Performance Specifications 4B and 8A in Appendix B, part 
60, and the appendix to subpart EEE, part 63--Quality Assurance 
Procedures for Continuous Emissions Monitors Used for Hazardous 
Waste Combustors, Section 6.3).
    \233\ You would not be required to assume these one-minute 
values if you use a CEMS that meets the performance specifications 
for a range that is higher than the recorded one-minute average. In 
this case, the CEMS must meet performance specifications for the 
higher range as well as the ranges specified in the performance 
specifications in Appendix B, part 60. See Sec. 63.1209 (a)(3) and 
(a)(4).
---------------------------------------------------------------------------

    For the reasons discussed above, we conclude that national 
requirements for batch feed operating parameter limits are not 
warranted.
    c. Activated Carbon Injection. If your combustor is equipped with 
an activated carbon injection system, you must establish and comply 
with limits on the following operating parameters: Good particulate 
matter control, minimum carbon feedrate, minimum carrier fluid flowrate 
or nozzle pressure drop, and identification of the carbon brand and 
type or the adsorption characteristics of the carbon. These are the 
same compliance parameters that we proposed. See 61 FR at 17424.
    i. Good Particulate Matter Control. You must comply with the 
operating parameter limits for particulate matter control (see 
discussion in Section VII.D.6 below and Sec. 63.1209(m)) because carbon 
injection controls dioxin/furan in conjunction with particulate matter 
control. Dioxin/furan is adsorbed onto carbon that is injected into the 
combustion gas, and the carbon is removed from stack gas by a 
particulate control device.
    Although we proposed to require good particulate matter control as 
a control technique for dioxin/furan irrespective of whether carbon 
injection was used, commenters indicate that we have no data 
demonstrating the relationship between particulate matter and dioxin/
furan emissions. Commenters further indicate that dioxin/furan occur 
predominately in the gas phase, not adsorbed onto particulate. We agree 
with commenters that hazardous waste combustors operating under the 
good combustion practices required by this final rule are not likely to 
have significant carbon particulates in stack gas (i.e., because 
carbonaceous particulates (soot) are indicative of poor combustion 
efficiency). Thus, unless activated carbon injection is used as a 
control technique, dioxin/furan will occur predominately in the gas 
phase. We therefore conclude that requiring good particulate control as 
a control technique for dioxin/furan is not warranted unless a source 
is equipped with activated carbon injection.234
---------------------------------------------------------------------------

    \234\ We discuss below, however, that good particulate matter 
control is also required if a source is equipped with a carbon bed. 
This is to ensure that particulate control upstream of the carbon 
bed is maintained to performance test levels to prevent blinding of 
the bed and loss of removal efficiency.
---------------------------------------------------------------------------

    ii. Minimum Carbon Feedrate. As proposed, you must establish and 
continuously monitor a limit on minimum carbon feedrate to ensure that 
dioxin/furan removal efficiency is maintained. You must establish an 
hourly rolling average feedrate limit based on operations during the 
comprehensive performance test. The hourly rolling average limit is 
established as the average of the test run averages. See Part Five, 
Sections VII.B.1 and B.3 above for a discussion of the approach for 
calculating limits from comprehensive performance test data.
    iii. Minimum Carrier Fluid Flowrate or Nozzle Pressure Drop. A 
carrier fluid, gas or liquid, is necessary to transport and inject the 
carbon into the gas stream. As proposed, you must establish and 
continuously monitor a limit on either minimum carrier fluid flowrate 
or pressure drop across the nozzle to ensure that the flow and 
dispersion of the injected carbon into the flue gas stream is 
maintained.
    We proposed to require you to base the limit on the carbon 
injection manufacturer's specifications. One commenter notes that there 
are no manufacturer specifications for carrier gas flowrate or pressure 
drop. Therefore, the final rule allows you to use engineering 
information and principles to establish the limit for minimum carrier 
fluid flowrate or pressure drop across the injection nozzle. You must 
identify the limit and the rationale for deriving it in the 
comprehensive performance test plan that you submit for review and 
approval.
    iv. Identification of Carbon Brand and Type or Adsorption 
Properties. You must either identify the carbon brand and type used 
during the comprehensive performance test and continue using that 
carbon, or identify the adsorption properties of that carbon and use a 
carbon having equivalent or better properties. This will ensure that 
the carbon's adsorption properties are maintained.235
---------------------------------------------------------------------------

    \235\ Examples of carbon properties include specific surface 
area, pore volume, average pore size, pore size distribution, bulk 
density, porosity, carbon source, impregnation, and activization 
procedure. See USEPA, ``Technical Support Document for HWC MACT 
Standards, Volume IV: Compliance with the HWC MACT Standards,'' July 
1999.
---------------------------------------------------------------------------

    We proposed to require you to use the same brand and type of carbon 
that was

[[Page 52941]]

used during the comprehensive performance test. Commenters object to 
this requirement and suggest that they should have the option of using 
alternative types of carbon that would achieve equivalent or better 
performance than the carbon used during the performance test. We 
concur, and the final rule allows you to document in the comprehensive 
performance test plan key parameters that affect adsorption and the 
limits you have established on those parameters based on the carbon to 
be used during the performance test. You may substitute at any time a 
different brand or type of carbon provided that the replacement has 
equivalent or improved properties and conforms to the key sorbent 
parameters you have identified. You must include in the operating 
record written documentation that the substitute carbon will provide 
the same level of control as the original carbon.
    d. Activated Carbon Bed. If your combustor is equipped with an 
activated carbon bed, you must establish and comply with limits on the 
following operating parameters: good particulate matter control; 
maximum age of each carbon bed segment; identification of carbon brand 
and type or adsorption properties, and maximum temperature at the inlet 
or exit of the bed. These are the same compliance parameters that we 
proposed. See 61 FR at 17424.
    i. Good Particulate Matter Control. You must comply with the 
operating parameter limits for particulate matter control (see 
discussion in Section VII.D.6 below and Sec. 63.1209(m)). If good 
control of particulate matter is not maintained prior to the inlet to 
the carbon bed, particulate matter could contaminate the bed and affect 
dioxin/furan removal efficiency. In addition, if particulate matter 
control is used downstream from the carbon bed, those controls must 
conform to good particulate matter control. This is because this 
``polishing'' particulate matter control device may capture carbon-
containing dioxin/furan that may escape from the carbon bed. Thus, the 
efficiency of this polishing control must be maintained to ensure 
compliance with the dioxin/furan emission standard.
    ii. Maximum Age of Each Bed Segment. As proposed, you must 
establish a maximum age of each bed segment to ensure that removal 
efficiency is maintained. Because activated carbon removes dioxin/furan 
(and mercury) by adsorption, carbon in the bed becomes less effective 
over time as the active sites for adsorption become occupied. Thus, bed 
age is an important operating parameter.
    At proposal, we requested comment on using carbon aging or some 
form of a breakthrough calculation to identify a limit on carbon age. 
See 61 FR at 17424. A breakthrough calculation would give a theoretical 
minimum carbon change-out schedule that you could use to ensure that 
breakthrough (i.e., the dramatic reduction in efficiency of the carbon 
bed due to too many active sites being occupied) does not occur.
    Commenters indicate that carbon effectiveness depends on the carbon 
bed age and pollutant types and concentrations in the gas streams, and 
therefore a carbon change-out schedule should be based on a 
breakthrough calculation rather than carbon age. We agree that a 
breakthrough calculation may be a better measurement of carbon 
effectiveness, but it would be difficult to define generically for all 
situations. A breakthrough calculation could be performed only after 
experimentation determines the relationship between incoming adsorbed 
chemicals and the adsorption rate of the carbon. The adsorption rate of 
carbon could be determined experimentally, but the speciation of 
adsorbed chemicals in a flue gas stream is site-specific and may vary 
greatly at a given site over time.
    We conclude that because carbon age contributes to carbon 
ineffectiveness, it serves as an adequate surrogate and is less 
difficult to implement on a national basis. Therefore, the rule 
requires sources to identify maximum carbon age as the maximum age of 
each bed segment during the comprehensive performance test. Carbon age 
is measured in terms of the cumulative volume of combustion gas flow 
through the carbon since its addition to the bed. Sources may use the 
manufacturer's specifications rather than actual bed age during the 
initial comprehensive performance test to identify the initial limit on 
maximum bed age. If you elect to use manufacturer's specifications for 
the initial limit on bed age, you must also recommend in the 
comprehensive performance test plan submitted for review and approval a 
schedule of dioxin/furan testing prior to the confirmatory performance 
test that will confirm that the manufacturer's specification of bed age 
is sufficient to ensure that you maintain compliance with the emission 
standard.
    If either existing or new sources prefer to use some form of 
breakthrough calculation to establish maximum bed age, you may petition 
permitting officials under Sec. 63.1209(g)(1) 236 to apply 
for an alternative monitoring scheme.
---------------------------------------------------------------------------

    \236\ We have incorporated the alternative monitoring provisions 
of Sec. 63.8(f) in Sec. 63.1209(g)(1) so that alternative monitoring 
provisions for nonCEMS CMS can be implemented by authorized States. 
The alternative monitoring provisions of Sec. 63.1209(g)(1) do not 
apply to CEMS, however. The alternative monitoring provisions of 
Sec. 63.8(f) continue to apply to CEMS because implementation of 
those provisions is not eligible to be delegated to States at this 
time.
---------------------------------------------------------------------------

    iii. Identification of Carbon Brand and Type or Adsorption 
Properties. You must either identify the carbon brand and type used 
during the comprehensive performance test and continue using that 
carbon, or identify the adsorption properties of that carbon and use a 
carbon having equivalent or better properties. This requirement is 
identical to that discussed above for activated carbon injection 
systems.
    iv. Maximum Temperature at the Inlet or Exit of the Bed. You must 
establish and continuously monitor a limit on the maximum temperature 
at the inlet or exit of the carbon bed. This is because a combustion 
gas temperature spike can cause adsorbed dioxin/furan (and mercury) to 
desorb and reenter the gas stream. In addition, the adsorption 
properties of carbon are adversely affected at higher temperatures.
    At proposal, we requested comment on whether it would be necessary 
to control temperature at the inlet to the carbon bed. See 61 FR at 
17425. Some commenters support temperature control noting the concern 
that temperature spikes could cause desorption of dioxin/furan (and 
mercury). We concur, and are requiring you to establish a maximum 
temperature limit at the inlet or exit of the bed. We are allowing you 
the option of measuring temperature at either end of the bed to give 
you greater flexibility in locating the temperature continuous 
monitoring system. Monitoring temperature at either end of the bed 
should be adequate to ensure that bed temperatures are maintained at 
levels not exceeding those during the comprehensive performance test 
(because the temperature remains relatively constant across the bed).
    You must establish an hourly rolling average temperature limit 
based on operations during the comprehensive performance test. The 
hourly rolling average limit is established as the average of the test 
run averages. See Part Five, Sections VII.B.1 and B.3 above for a 
discussion of the approach for calculating limits from comprehensive 
performance test data.
    e. Catalytic Oxidizer. If your combustor is equipped with a 
catalytic oxidizer, you must establish and comply with limits on the 
following operating parameters: minimum gas temperature

[[Page 52942]]

at the inlet of the catalyst; maximum age in use; catalyst replacement 
specifications; and maximum flue gas temperature at the inlet of the 
catalyst. These are the same compliance parameters that we proposed. 
See 61 FR at 17425.
    Catalytic oxidizers used to control stack emissions are similar to 
those used in automotive and industrial applications. The flue gas 
passes over catalytic metals, such as palladium and platinum, supported 
by an alumina washcoat on some metal or ceramic substrate. When the 
flue gas passes through the catalyst, a reaction takes place similar to 
combustion, converting hydrocarbons to carbon monoxide, then carbon 
dioxide. Catalytic oxidizers can also be ``poisoned'' by lead and other 
metals in the same manner as automotive and industrial catalysts.
    i. Minimum Gas Temperature at the Inlet of the Catalyst. You must 
establish and continuously monitor a limit on the minimum flue gas 
temperature at the inlet of the catalyst to ensure that the catalyst is 
above light-off temperature. Light-off temperature is that minimum 
temperature at which the catalyst is hot enough to catalyze the 
reactions of hydrocarbons and carbon monoxide.
    You must establish an hourly rolling average temperature limit 
based on operations during the comprehensive performance test. The 
hourly rolling average limit is established as the average of the test 
run averages.
    ii. Maximum Time In-Use. You must establish a limit on the maximum 
time in-use of the catalyst because a catalyst is poisoned and 
generally degraded over use. You must establish the limit based on the 
manufacturer's specifications.
    iii. Catalytic Metal Loading, Maximum Space-Time, and Substrate 
Construct. When you replace a catalyst, the replacement must be of the 
same design to ensure that destruction efficiency is maintained. 
Consequently, the rule requires that you specify the following catalyst 
properties: Loading of catalytic metals; space-time; and monolith 
substrate construction.
    Catalytic metal loading is important because, without sufficient 
catalytic metal on the catalyst, it does not function properly. Also, 
some catalytic metals are more efficient than others. Therefore, the 
replacement catalyst must have at least the same catalytic metal 
loading for each catalytic metal as the catalyst used during the 
comprehensive performance test.
    Space-time, expressed in inverse seconds (s-1), is 
defined as the maximum rated volumetric flow through the catalyst 
divided by the volume of the catalyst. This is important because it is 
a measure of the gas flow residence time and, hence, the amount of time 
the flue gas is in the catalyst. The longer the gas is in the catalyst, 
the more time the catalyst has to cause hydrocarbons and carbon 
monoxide to react. Replacement catalysts must have the same or lower 
space-time as the one used during the comprehensive performance test.
    Substrate construction is also an important parameter affecting 
destruction efficiency of the catalyst. Three factors are important. 
First, substrates for industrial applications are typically monoliths, 
made of rippled metal plates banded together around the circumference 
of the catalyst. Ceramic monoliths and pellets can also be used. 
Because of the many types of substrates, you must use the same 
materials of construction, monolith or pellets and metal or ceramic, 
used during the comprehensive performance test as replacements. Second, 
monoliths form a honeycomb like structure when viewed from one end. The 
pore density (i.e., number of pores per square inch) is critical 
because the pores must be small enough to ensure intimate contact 
between the flue gas and the catalyst but large enough to allow 
unrestricted flow through the catalyst. Therefore, if you use a 
monolith substrate during the comprehensive performance test, the 
replacement catalyst must have the same pore density. Third, catalysts 
are supported by a washcoat, typically alumina. We require that 
replacement catalysts have the same type and loading of washcoat as was 
on the catalyst used during the comprehensive performance test.
    iv. Maximum Flue Gas Temperature at the Inlet to the Catalyst. You 
must establish and continuously monitor a limit on maximum flue gas 
temperature at the inlet to the catalyst. Inlet temperature is 
important because sustained high flue gas temperature can result in 
sintering of the catalyst, degrading its performance. You must 
establish the limit as an hourly rolling average, based on manufacturer 
specifications.
    In the proposed rule, we would have allowed a waiver from these 
operating parameter limits if you documented to the Administrator that 
establishing limits on other operating parameters would be more 
appropriate to ensure that the dioxin/furan destruction efficiency of 
the oxidizer is maintained after the performance test. See 61 FR at 
17425. We are not finalizing a specific waiver for catalytic oxidizer 
parameters because you are eligible to apply for the same relief under 
the existing alternative monitoring provisions of Sec. 63.1209(g)(1).
    f. Dioxin/Furan Formation Inhibitor. If you feed a dioxin/furan 
formation inhibitor into your combustor as an additive (e.g., sulfur), 
you must: (1) Establish a limit on minimum inhibitor feedrate; and (2) 
identify either the brand and type of inhibitor or the properties of 
the inhibitor.
    i. Minimum Inhibitor Feedrate. As proposed, you must establish and 
continuously monitor a limit on minimum inhibitor feedrate to help 
ensure that dioxin/furan formation reactions continue to be inhibited 
at levels of the comprehensive performance test. See 61 FR at 17425. 
You must establish an hourly rolling average feedrate limit based on 
operations during the comprehensive performance test. The hourly 
rolling average limit is established as the average of the test run 
averages.
    This minimum inhibitor feedrate pertains to additives to 
feedstreams, not naturally occurring inhibitors that may be found in 
fossil fuels, hazardous waste, or raw materials. At proposal, we 
requested comment on whether it would be appropriate to establish 
feedrate limits on the amount of naturally occurring inhibitors based 
on levels fed during the comprehensive performance test. See 61 FR at 
17425. For example, it is conceivable that a source would choose to 
burn high sulfur fuel or waste only during the comprehensive 
performance test and then switch back to low sulfur fuels or waste 
after the test, thus reducing dioxin/furan emissions during the 
comprehensive test to levels that would not be maintained after the 
test. Commenters do not provide information on this matter and we do 
not have enough information on the types or effects of naturally 
occurring substances that may act as inhibitors. Therefore, the final 
rule does not establish limits on naturally occurring inhibitors. 
Permitting officials, however, may choose to address the issue of 
naturally occurring inhibitors when warranted during review of the 
comprehensive performance test plan. (See discretionary authority of 
permitting officials under Sec. 63.1209(g)(2) to impose additional or 
alternative operating parameter limits on a site-specific basis.)
    ii. Identification of Either the Brand and Type of Inhibitor or the 
Properties of the Inhibitor. As proposed, you must either identify the 
inhibitor brand and type used during the comprehensive performance test 
and continue using that inhibitor, or identify the properties of that 
inhibitor that affect its ability to inhibit dioxin/furan formation 
reactions and use an inhibitor having equivalent

[[Page 52943]]

or better properties. This requirement is identical to that discussed 
above for activated carbon systems.
2. What Are the Operating Parameter Limits for Mercury?
    You must maintain compliance with the mercury emission standard by 
establishing and complying with limits on operating parameters. See 
Sec. 63.1209(l). The following table summarizes these operating 
parameter limits. All sources must comply with the limits on mercury 
feedrate. Other operating parameter limits apply if you use the mercury 
control technique to which they apply.

[GRAPHIC] [TIFF OMITTED] TR30SE99.002


    Mercury emissions from hazardous waste combustors are controlled by 
controlling the feedrate of mercury, wet scrubbing to remove soluble 
mercury species (e.g, mercuric chloride), and carbon adsorption. We 
discuss below the operating parameter limits that apply to each control 
technique. We also discuss why we are not limiting the temperature at 
the inlet to the dry particulate matter control device as a control 
parameter for mercury.
    a. Maximum Mercury Feedrate. As proposed, you must establish and 
comply with a maximum total feedrate limit for mercury for all 
feedstreams. See 61 FR at 17428. The amount of mercury fed into the 
combustor directly affects emissions and the removal efficiency of 
emission control equipment. To establish and comply with the feedrate 
limit, you must sample and analyze and continuously monitor the 
flowrate of all feedstreams (including hazardous waste, raw materials, 
and other fuels and additives) except natural gas, process air, and 
feedstreams from vapor recovery systems for mercury content.\237\ As 
proposed, you must establish a maximum 12-hour rolling average feedrate 
limit based on operations during the comprehensive performance test as 
the average of the test run averages.
---------------------------------------------------------------------------

    \237\ See discussion in Section VII.D.3. below in the text for 
rationale for exempting these feedstreams for monitoring for mercury 
content.
---------------------------------------------------------------------------

    Rather than establish mercury feedrate limits as the levels fed 
during the comprehensive performance test, you may request as part of 
your performance test plan to use the mercury feedrates and associated 
emission rates during the performance test to extrapolate to higher 
allowable feedrate limits and emission rates. See Section VII.D.3 below 
for a discussion of the rationale and procedures for obtaining approval 
to extrapolate metal feedrates.
    In addition, you may use the performance test waiver provision 
under Sec. 63.1207(m) to document compliance with the emission 
standard. Under that provision, you must monitor the total mercury 
feedrate from all feedstreams and the gas flowrate and document that 
the maximum theoretical emission concentration does not exceed the 
mercury emission standard. Thus, this is another compliance approach 
where you would not establish feedrate limits on mercury during the 
comprehensive performance test.
    b. Wet Scrubbing. As proposed, if your combustor is equipped with a 
wet scrubber, you must establish and comply with limits on the same 
operating parameters (and in the same manner) that apply to compliance 
assurance with the hydrochloric acid/chlorine gas emission standard for 
wet scrubbers. See Section VII.D.5 below for a discussion of those 
parameters.
    c. Activated Carbon Injection. As proposed, if your combustor is 
equipped with an activated carbon injection system, you must establish 
and comply with limits on the same operating parameters (and in the 
same manner) that apply to compliance assurance with the dioxin/furan 
emission standard for activated carbon injection systems.
    d. Activated Carbon Bed. As proposed, if your combustor is equipped 
with an activated carbon bed, you must establish and comply with limits 
on the same operating parameters (and in the same manner) that apply to 
compliance assurance with the dioxin/furan emission standard for 
activated carbon beds.
    e. Consideration of a Limit on Maximum Inlet Temperature to a Dry 
Particulate Matter Control Device. The final rule does not require you 
to control inlet temperature to a dry particulate

[[Page 52944]]

matter air pollution control device to control mercury emissions. At 
proposal, we expressed concern that high inlet temperatures to a dry 
particulate matter control device could cause low mercury removal 
efficiency because mercury volatility increases with increasing 
temperature. See 61 FR at 17428. Therefore, we proposed to limit inlet 
temperatures to levels during the comprehensive performance test.
    Commenters suggest that a maximum inlet temperature for dry 
particulate matter control devices is not needed because mercury is 
generally highly volatile within the range of inlet temperatures of all 
dry particulate matter control devices. We are persuaded by the 
commenters that inlet temperature to these devices is not critically 
important to mercury control, although temperature can potentially have 
an impact on the volatility of certain mercury species (e.g., oxides). 
We conclude that the other operating parameter limits are sufficient to 
ensure compliance with the mercury emission standard. In particular, we 
note that a limit on maximum inlet temperature to these control devices 
is required for compliance assurance with the dioxin/furan, 
semivolatile metal, and low volatile metal emission standards.
3. What Are the Operating Parameter Limits for Semivolatile and Low 
Volatile Metals?
    You must maintain compliance with the semivolatile metal and low 
volatile metal emission standards by establishing and complying with 
limits on operating parameters. See Sec. 63.1209(n). The following 
table summarizes these operating parameter limits. All sources must 
comply with the limits on feedrates of semivolatile metals, low 
volatile metals, and chlorine. Other operating parameter limits apply 
depending on the type of particulate matter control device you use.

BILLING CODE 6560-50-P

[[Page 52945]]

[GRAPHIC] [TIFF OMITTED] TR30SE99.003



BILLING CODE 6560-50-C

[[Page 52946]]

    Semivolatile and low volatile metal emissions from hazardous waste 
combustors are controlled by controlling the feedrate of the metals and 
particulate matter emissions. In addition, because chlorine feedrate 
can affect the volatility of metals and thus metals levels in the 
combustion gas, and because the temperature at the inlet to the dry 
particulate matter control device can affect whether the metal is in 
the vapor (gas) or solid (particulate) phase, control of these 
parameters is also important to control emissions of these metals. We 
discuss below the operating parameter limits that apply to each control 
technique. We also discuss use of metal surrogates during performance 
testing, provisions for allowing extrapolation of performance test 
feedrate levels to calculate metal feedrate limits, and conditional 
waiver of the limit on low volatile metals in pumpable feedstreams.
    a. Good Particulate Matter Control. As proposed, you must comply 
with the operating parameter limits for particulate matter control (see 
discussion in Section VII.D.6 below and Sec. 63.1209(m)) because 
semivolatile and low volatile metals are primarily in the solid 
(particulate) phase at the gas temperature (i.e., 400 deg.F or lower) 
of the particulate matter control device. Thus, these metals are 
largely removed from flue gas as particulate matter.
    b. Maximum Inlet Temperature to Dry Particulate Matter Control 
Device. As proposed, you must establish and continuously monitor a 
limit on the maximum temperature at the inlet to a dry particulate 
matter control device. Although most semivolatile and low volatile 
metals are in the solid, particulate phase at the temperature at the 
inlet to the dry control device mandated by today's rule (i.e., 
400 deg.F or lower), some species of these metals remain in the vapor 
phase. We are requiring a limit on maximum temperature at the inlet to 
the control device to ensure that the fraction of these metals that are 
volatile (and thus not controlled by the particulate matter control 
device) does not increase during operations after the comprehensive 
performance test.
    As proposed, you must establish an hourly rolling average 
temperature limit based on operations during the comprehensive 
performance test. The hourly rolling average limit is established as 
the average of the test run averages. See Part Five, Sections VII.B.1 
and B.3 above for a discussion of the approach for calculating limits 
from comprehensive performance test data.
    Commenters suggest that this limit may conflict with the maximum 
temperature limit at the inlet to the particulate matter control device 
that is also required for compliance assurance with the dioxin/furan 
emission standard. We do not understand commenters' concern. If for 
some reason the dioxin/furan and metals emissions tests are not 
conducted simultaneously, the governing temperature limit will be the 
lower of the limits established from the separate tests. This provides 
compliance assurance for both standards.
    c. Maximum Semivolatile and Low Volatile Metals Feedrate Limits. 
You must establish limits on the maximum total feedrate of both 
semivolatile metals and low volatile metals from all feedstreams at 
levels fed during the comprehensive performance test. Metals feedrates 
are related to emissions in that, as metals feedrates increase at a 
source, metals emissions increase. See Part Four, Section II.A above 
for discussion on the relationship between metals feedrates and 
emissions. Thus, metals feedrates are an important control technique.
    For low volatile metals, you must also establish a limit on the 
maximum total feedrate of pumpable liquids from all feedstreams. The 
rule requires a separate limit for pumpable feedstreams because metals 
present in pumpable feedstreams may partition between the combustion 
gas and bottom ash (or kiln product) at a higher rate than metals in 
nonpumpable feedstreams (i.e., low volatile metals in pumpable 
feedstreams tend to partition primarily to the combustion gas). The 
rule does not require a separate limit for semivolatile metals in 
pumpable feedstreams because partitioning between the combustion gas 
and bottom ash or product for these metals does not appear to be 
affected by the physical state of the feedstream.238
---------------------------------------------------------------------------

    \238\ See USEPA., ``Technical Support Document for HWC MACT 
Standards, Volume IV: Compliance with the MACT Standards,'' February 
1998.
---------------------------------------------------------------------------

    To establish and comply with the feedrate limits, you must sample 
and analyze and continuously monitor the flowrate of all feedstreams 
(including hazardous waste, raw materials, and other fuels and 
additives) except natural gas, process air, and feedstreams from vapor 
recovery systems for semivolatile and low volatile metals content. As 
proposed, you must establish maximum 12-hour rolling average feedrate 
limits based on operations during the comprehensive performance test as 
the average of the test run averages.
    i. Use of Metal Surrogates. You may use one metal within a 
volatility group as a surrogate during comprehensive performance 
testing for other metals in that volatility group. For example, you may 
use chromium as a surrogate during the performance test for all low 
volatile metals. Similarly, you may use lead as a surrogate for 
cadmium, the other semivolatile metal. This is because the metals 
within a volatility group have generally the same volatility. Thus, 
they will generally be equally difficult to control with an emissions 
control device.
    In addition, you may use either semivolatile metal as a surrogate 
for any low volatile metal because semivolatile metals will be more 
difficult to control than low volatile metals.239 This will 
help alleviate concerns regarding the need to spike each metal during 
comprehensive performance testing. If you want to spike metals, you 
need not spike each metal to comply with today's rule but only one 
metal within a volatility group (or potentially one semivolatile metal 
for both volatility groups).
---------------------------------------------------------------------------

    \239\ This is because a greater portion of semivolatile metals 
volatilize in the combustion chamber and condenses in the flue gas 
on small particulates or as fume. The major portion of low volatile 
metals in flue gas are entrained on larger particulates (rather than 
condensing from volatile species) and are thus easier to remove with 
a particulate control device.
---------------------------------------------------------------------------

    ii. Extrapolation of Performance Test Feedrate Levels to Calculate 
Metal Feedrate Limits.240 You may request under 
Sec. 63.1209(n)(2)(ii) to use the metal feedrates and emission rates 
associated with the comprehensive performance test to extrapolate 
feedrate limits and emission rates at levels higher than demonstrated 
during the performance test. Extrapolation can be advantageous because 
it avoids much of the spiking that sources normally undertake during 
compliance testing and the associated costs, risks to operating and 
testing personnel, and environmental loading from emissions.
---------------------------------------------------------------------------

    \240\ Although this extrapolation discussion is presented in 
context of semivolatile and low volatile metal feedrates, similar 
provisions could be implemented for mercury feedrates.
---------------------------------------------------------------------------

    Under an approved extrapolation approach, you would be required to 
feed metals at no less than normal rates to narrow the amount of 
extrapolation requested. Further, we expect that some spiking would be 
desired to increase confidence in the measured, performance test 
feedrate levels that will be used to project feedrate limits (i.e., the 
errors associated with sampling and analyzing heterogeneous feedstreams 
can be minimized by spiking known quantities). Extrapolation approaches 
that request feedrate limits that are significantly higher than the 
historical range of

[[Page 52947]]

feedrates should not be approved. Extrapolated feedrate limits should 
be limited to levels within the range of the highest historical 
feedrates for the source. We are taking this policy position to avoid 
creating an incentive to burn wastes with higher than historical levels 
of metals. Metals are not destroyed by combustion but rather are 
emitted as a fraction of the amount fed to the combustor. If you want 
to burn wastes with higher than historical levels of metals, you must 
incur the costs and address the hazards to plant personnel and testing 
crews associated with spiking metals into your feedstreams during 
comprehensive performance testing.
    Although we also investigated downward interpolation (i.e., between 
the measured feedrate and emission level and zero), we are concerned 
that downward interpolation may not be conservative. Our data indicates 
that system removal efficiency can decrease as metal feedrate 
decreases. Thus, actual emissions may be higher than emissions 
projected by interpolation for lower feedrates. Consequently, we are 
not allowing downward interpolation.
    We are not specifying an extrapolation methodology to provide as 
much flexibility as possible to consider extrapolation methodologies 
that would best meet individual needs. We have investigated 
extrapolation approaches 241 and discussed in the May 1997 
NODA a statistical extrapolation methodology. Commenters raise 
concerns, however, about defining a single acceptable extrapolation 
method. They note that other methods might be developed in the future 
that prove to be better, especially for a given source. We agree that 
the approach discussed in the NODA may be too inflexible and are not 
promulgating it today.242 Consequently, today's rule does 
not specify a single method but allows you to recommend a method for 
review and approval by permitting officials.
---------------------------------------------------------------------------

    \241\ See USEPA, ``Draft Technical Support Document for HWC MACT 
Standards (NODA), Volume III: Evaluation of Metal Emissions Database 
to Investigate Extrapolation and Interpolation Issues,'' April 1997.
    \242\ We plan to develop guidance on approaches that provide 
greater flexibility.
---------------------------------------------------------------------------

    Your recommended extrapolation methodology must be included in the 
performance test plan. See Sec. 63.1207(f)(1)(x). Permitting officials 
will review the methodology considering in particular whether: (1) 
Performance test metal feedrates are appropriate (i.e., whether 
feedrates are at least at normal levels, whether some level of spiking 
would be appropriate depending on the heterogeneity of the waste, and 
whether the physical form and species of spiked material is 
appropriate); and (2) the requested, extrapolated feedrates are 
warranted considering historical metal feedrate data.
    We received comments both in favor of and in opposition to metals 
extrapolation and interpolation. Those in favor suggest extrapolation 
would simplify the comprehensive performance test procedure, reduce 
costs, and decrease emissions during testing. Those in opposition are 
concerned about: (1) Whether there is a predictable relationship 
between feedrates and emission rates; (2) the possibility of higher 
overall metals loading to the environment over the life of the facility 
(i.e., because higher feedrate limits would be relatively easy to 
obtain); (3) the difficulty in defining a ``normal'' feedrate for 
facilities with variable metal feeds; and (4) whether all conditions 
influencing potential metals emissions, such as combustion temperature 
and metal compound speciation, could be adequately considered.
    Given the pros and cons associated with various extrapolation 
methodologies and policies, we are still concerned that sources would 
be able to: (1) Feed metals at higher rates without a specific 
compliance demonstration of the associated metals emissions; and (2) 
obtain approval to feed metals at higher levels than normal, even 
though all combustion sources should be trying to minimize metals 
feedrates. However, because the alternative is metal spiking (as 
evidenced in facility testing for BIF compliance) and metal spiking is 
a significant concern as well, we find that the balance is better 
struck by allowing, with site-specific review and where warranted 
approval, extrapolation as a means to reduce unnecessary emissions, 
reduce unnecessary costs incurred by facilities, and better protect the 
health of testing personnel during performance tests.
    iii. Conditional Waiver of Limit on Low Volatile Metals in Pumpable 
Feedstreams. Commenters indicate that they may want to base feedrate 
limits only on the worst-case feedstream--pumpable hazardous waste. The 
feedrate limit would be based only on the feedrate of the pumpable 
hazardous waste during the comprehensive performance test, even though 
nonpumpable feedstreams would be contributing some metals to emissions. 
In this situation, commenters suggest that separate feedrate limits for 
total and pumpable feedstreams would not be needed. We agree that if 
you define the total feedstream feedrate limit as the pumpable 
feedstream feedrate during the performance test, dual limits are not 
required. The feedrate of metals in total feedstreams must be monitored 
and shown to be below the pumpable feedstream-based limit. See 
Sec. 63.1209(n)(2)(C).
    iv. Response to other Comments. We discuss below our response to 
several other comments: (1) Recommendation for national uniform 
feedrate limits; (2) concerns that feedstream monitoring is 
problematic; and (3) recommendations that monitoring natural gas and 
vapor recovery system feedstreams is unnecessary.
    A commenter states that nationally uniform feedrate limits are 
needed for metals and chlorine and that any other approach would be 
inconsistent with the CAA. The commenter stated that hazardous waste 
combustion device operators should not be allowed to self-select any 
level of toxic metal feedrate just because they can show compliance 
with the MACT standard. We believe that standards prescribing national 
feedrate limits on metals or chlorine are not necessary to ensure MACT 
control of metals and hydrochloric acid/chlorine gas and may be overly 
restrictive. Emissions of metals and hydrochloric acid/chlorine gas are 
controlled by controlling the feedrate of metals and chlorine, and 
emission control devices. In developing MACT standards for a source 
category, if we can identify emission levels that are being achieved by 
the best performing sources using MACT control, we generally establish 
the MACT standard as an emission level rather than prescribed operating 
limits (e.g., feedrate limits). This approach is preferable because it 
gives the source the option of determining the most cost-effective 
measures to comply with the standard. Some sources may elect to comply 
with the emission standards using primarily feedrate control, while 
others may elect to rely primarily on emission controls. Under either 
approach, the emission levels are equivalent to those being achieved by 
the best performing existing sources. Other factors that we considered 
in determining to express the standards as an emission level rather 
than feedrate limits include: (1) There is not a single, universal 
correlation factor between feedrate and metal emissions to use to 
determine a national feedrate that would be equivalent to the emission 
levels achieved by the best performing sources; (2) emission standards 
communicate better to the public that meaningful controls are being 
applied because the hazardous waste combustor

[[Page 52948]]

emission standards can be compared to standards for other waste 
combustors (e.g., municipal and medical waste combustors) and 
combustion devices; and (3) CEMS, the ultimate compliance assurance 
tool that we encourage sources to use,243 are incompatible 
with standards expressed as feedrate limits.
---------------------------------------------------------------------------

    \243\ As discussed previously in the text, feedrate limits as a 
compliance tool can be problematic for difficult to sample or 
analyze feedstreams. Further, the emissions resulting from a given 
feedrate level may increase (or decrease) over time, providing 
uncertainty about actual emissions.
---------------------------------------------------------------------------

    Another commenter is concerned that feedrate monitoring of highly 
heterogeneous waste streams is problematic and analytical turnaround 
times can be rather long. The commenter suggests that alternatives 
beyond feedstream monitoring (such as predictive emissions monitoring) 
should be allowed. Although we acknowledge that there may be 
difficulties in monitoring the feedrate of metals or chlorine in 
certain waste streams, there generally is no better way to assure 
compliance with these standards other than using CEMS. Predictive 
modeling appears to introduce unnecessarily some greater compliance 
uncertainty than feedstream testing. Thus, we conclude that feedstream 
monitoring is a necessary monitoring tool if a multimetals CEMS is not 
used. (We also note that feedstream monitoring under MACT will not be 
substantially more burdensome or problematic than the requirements now 
in place under RCRA regulations.)
    In addition, another commenter suggests that sources should not 
have to monitor metals and chlorine in natural gas feedstreams because 
it is impractical and levels are low and unvarying. The commenter 
suggests that sources should be allowed to use characterization data 
from natural gas vendors. We agree that the cost and possible hazards 
of monitoring natural gas for metals and chlorine is not warranted 
because our data shows metals are not present at levels of concern. 
Therefore, you are not required to monitor metals and chlorine levels 
in natural gas feedstreams. However, you must document in the 
comprehensive performance test plan the expected levels of these 
constituents and account for the expected levels in documenting 
compliance with feedrate limits (e.g., by assuming worst-case 
concentrations and monitoring the natural gas flowrate). See 
Sec. 63.1209(c)(5).
    Finally, some commenters are concerned that feedstreams from vapor 
recovery systems (e.g., waste fuel tank and container emissions) are 
difficult, costly, and often dangerous to monitor frequently for metals 
and chlorine levels. Particularly because of some of the safety issues 
concerned, the rule does not require continuous monitoring of metals 
and chlorine for feedstreams from vapor recovery systems. However, as 
is the case for natural gas, you must document in the comprehensive 
performance test plan the expected levels of these constituents and 
account for the expected levels in documenting compliance with feedrate 
limits.
    d. Maximum Chlorine Feedrate. As proposed, you must establish a 
limit on the maximum feedrate for total chlorine (both organic and 
inorganic) in all feedstreams based on the level fed during the 
comprehensive performance test. A limit on maximum chlorine feedrate is 
necessary because most metals are more volatile in the chlorinated 
form. Thus, for example, more low volatile metals may report to the 
combustion gas as a vapor than would be otherwise be entrained in the 
combustion gas absent the presence of chlorine. In addition, the vapor 
form of the metal is more difficult to control. Although most 
semivolatile and low volatile metal species are in the particulate 
phase at gas temperatures at the inlet to the particulate matter 
control device, semivolatile metals that condense from the vapor phase 
partition to smaller particulates and are more difficult to control 
than low volatile metals that are emitted in the form of entrained, 
larger particulates.
    To establish and comply with the feedrate limit, you must sample 
and analyze, and continuously monitor the flowrate, of all feedstreams 
(including hazardous waste, raw materials, and other fuels and 
additives) except natural gas, process air, and feedstreams from vapor 
recovery systems for total chlorine content. As proposed, you must 
establish a maximum 12-hour rolling average feedrate limit based on 
operations during the comprehensive performance test as the average of 
the test run averages.
    Commenters suggest that chlorine feedrate limits are not needed for 
sources with semivolatile and low volatile metal feedrates, when 
expressed as maximum theoretical emission concentrations, less than the 
emission standard. We agree. In this situation, you would be eligible 
for the waiver of performance test under Sec. 63.1207(m). The 
requirements of that provision (e.g., monitor and record metals 
feedrates and gas flowrates to ensure that metals feedrate, expressed 
as a maximum theoretical emission concentration, does not exceed the 
emission standard) apply in lieu of the operating parameter limits 
based on performance testing discussed above. We note, however, that 
you would still need to establish a maximum feedrate limit for total 
chlorine as an operating parameter limit for the hydrochloric acid/
chlorine gas emission standard (discussed below), unless you also 
qualified for a waiver of that emission standard under Sec. 63.1207(m).
4. What Are the Monitoring Requirements for Carbon Monoxide and 
Hydrocarbon?
    You must maintain compliance with the carbon monoxide and 
hydrocarbon emission standards using continuous emissions monitoring 
systems (CEMS). In addition, you must use an oxygen CEMS to correct 
continuously the carbon monoxide and hydrocarbon levels recorded by 
their CEMS to 7 percent oxygen.
    As proposed, the averaging period for carbon monoxide and 
hydrocarbon CEMS is a one-hour rolling average updated each minute. 
This is consistent with current RCRA requirements and commenters did 
not recommend an alternative averaging period.
    We also are promulgating performance specifications for carbon 
monoxide, hydrocarbon, and oxygen CEMS. The carbon monoxide and oxygen 
CEMS performance specifications are codified as Performance 
Specification 4B in appendix B, part 60. This performance specification 
is the same as the specification currently used for BIFs in appendix 
IX, part 266. It also is very similar to existing appendix B, part 60 
Performance Specifications 3 (for oxygen) and 4A (for carbon monoxide). 
New specification 4B references many of the provisions of 
Specifications 3 and 4A.
    The hydrocarbon CEMS performance specification is codified as 
Performance Specification 8A in appendix B, part 60. This specification 
is also identical to the specification currently used for BIFs in 
section 2.2 of appendix IX, part 266, with one exception. We deleted 
the quality assurance section and placed it in the appendix to subpart 
EEE of part 63 promulgated today to be consistent with our approach to 
part 60 performance specifications.
    We discuss below several issues pertaining to monitoring with these 
CEMS: (1) The requirement to establish site-specific alternative span 
values in some situations; (2) consequences of exceeding the span value 
of the CEMS; and (3) the need to adjust the oxygen correction factor 
during startup and shutdown.
    a. When Are You Required to Establish Site-Specific Alternative 
Span

[[Page 52949]]

Values? As proposed, if you normally operate at an oxygen correction 
factor of more than 2 (e.g., a cement kiln monitoring carbon monoxide 
in the by-pass duct), you must use a carbon monoxide or hydrocarbon 
CEMS with a span proportionately lower than the values prescribed in 
the performance specifications relative to the oxygen correction factor 
at the CEMS sampling point. See the appendix to Subpart EEE, part 63: 
Quality Assurance Procedures for Continuous Emissions Monitors Used for 
Hazardous Waste Combustors.
    This requirement arose from our experience with implementing the 
BIF rule when we determined that the prescribed span values for the 
carbon monoxide and hydrocarbon CEMS may lead to high error in 
corrected emission values due to the effects of making the oxygen 
correction. For example, a cement kiln may analyze for carbon monoxide 
emissions in the by-pass duct with oxygen correction factors on the 
order of 10. At the low range of the carbon monoxide CEMS span--200 ppm 
as prescribed by Performance Specification 4B--with an acceptable 
calibration drift of three percent, an error of 6 ppm is the result. 
Accounting for the oxygen correction factor of 10, however, drives the 
error in the measurement due to calibration drift up to 60 ppm. This is 
more than half the carbon monoxide emission standard of 100 ppm and is 
not acceptable. At carbon monoxide readings close to the 100 ppm 
standard, true carbon monoxide levels may be well above or well below 
the standard.
    Consider the same example under today's requirement. For an oxygen 
correction factor of 10, the low range span for the carbon monoxide 
CEMS must be 200 divided by 10, or 20 ppm. The allowable calibration 
drift of three percent of the span allows an error of 0.6 ppm at 20 
ppm. Applying an oxygen correction factor of 10 results in an absolute 
calibration drift error of 6ppm at an oxygen-corrected carbon monoxide 
reading of 200.
    b. What Are the Consequences of Exceeding the Span Value for Carbon 
Monoxide and Hydrocarbon CEMS? If you do not elect to use a carbon 
monoxide CEMS with a higher span value of 10,000 ppmv and a hydrocarbon 
CEMS with a higher span value of 500 ppmv, you must configure your CEMS 
so that a one-minute carbon monoxide value reported as 3,000 ppmv or 
greater must be recorded (and used to calculate the hourly rolling 
average) as 10,000 ppmv, and a one-minute hydrocarbon value reported as 
200 ppmv or greater must be recorded as 500 ppmv.
    If you elect to use a carbon monoxide CEMS with a span range of 0-
10,000 ppmv, you must use one or more carbon monoxide CEMS that meet 
the Performance Specification 4B for three ranges: 0-200 ppmv; 1-3,000 
ppmv; and 0-10,000 ppmv. Specification 4B provides requirements for the 
first two ranges. For the (optional) high range of 0-10,000 ppmv, the 
CEMS must also comply with Performance Specification 4B, except that 
the calibration drift must be less than 300 ppmv and calibration error 
must be less than 500 ppmv. These values are based on the allowable 
drift and error, expressed as a percentage of span, that the 
specification requires for the two lower span levels.
    If you elect to use a hydrocarbon CEMS with a span range of 0-500 
ppmv, you must use one or more hydrocarbon CEMS that meet Performance 
Specification 8A for two ranges: 0-100 ppmv, and 0-500 ppmv. 
Specification 8A provides requirements for the first range. For the 
(optional) high range of 0-500 ppmv, the CEMS must also comply with 
Performance Specification 8A, except: (1) The zero and high-level daily 
calibration gas must be between 0 and 100 ppmv and between 250 and 450 
ppmv, respectively; (2) the strip chart recorder, computer, or digital 
recorder must be capable of recording all readings within the CEMS 
measurement range and must have a resolution of 2.5 ppmv; (3) the CEMS 
calibration must not differ by more than 15 ppmv after each 
24 hour period of the seven day test at both zero and high levels; (4) 
the calibration error must be no greater than 25 ppmv; and (5) the zero 
level, mid-level, and high level values used to determine calibration 
error must be in the range of 0-200 ppmv, 150-200 ppmv, and 350-400 
ppmv, respectively. These requirements for the optional high range (0-
500 ppmv) are derived proportionately from the requirements in 
Specification 8A for the lower range (0-100 ppmv).
    The rule provides this requirement because we are concerned that, 
when carbon monoxide and hydrocarbon monitors record a one-minute value 
at the upper span level, the actual level of carbon monoxide or 
hydrocarbons may be much higher (i.e., these CEMS often ``peg-out'' at 
the upper span level). This has two inappropriate consequences. First, 
the source may actually be exceeding the carbon monoxide or hydrocarbon 
standard even though the CEMS indicates that it is not. Second, if the 
carbon monoxide or hydrocarbon hourly rolling average were to exceed 
the standard, triggering an automatic waste feed cutoff, the emission 
level may drop back below the standard much sooner than it otherwise 
would if the actual one-minute average emission levels were recorded 
(i.e., rather than one-minute averages pegged at the upper span value). 
Thus, this diminishes the economic disincentive for incurring automatic 
waste feed cutoffs of not being able to restart the hazardous waste 
feed until carbon monoxide and hydrocarbon levels are below the 
standard.
    We considered applying these ``out-of-span'' requirements when any 
recorded value (i.e., any value recorded by the CEMS on a frequency of 
at least every 15 seconds), rather than one-minute average values, 
exceeded the upper span level. Commenters point out, however, that CEMS 
may experience short-term electronic glitches that cause the monitored 
output to spike for a very short time period. We concur, and conclude 
that we should be concerned only about one-minute average values 
because these short-term electronic glitches (that are not caused by 
emission excursions) could result in an undesirable increase in 
automatic waste feed cutoffs.
    You may prefer to use carbon monoxide or hydrocarbon CEMS that have 
upper span values between 3,000 and 10,000 ppmv and between 100 and 500 
ppmv, respectively. If you believe that you would not have one-minute 
average carbon monoxide or hydrocarbon levels as high as 10,000 ppmv 
and 500 ppmv, respectively, you may determine that it would be less 
expensive to use monitors with lower upper span levels (e.g., you may 
be able to use a single carbon monoxide CEMS to meet performance 
specifications for all three spans--the two lower spans required by 
Specification 4B, and a higher span (but less than 10,000)). You must 
still record, however, any one-minute average carbon monoxide or 
hydrocarbon levels that are at or above the span as 10,000 ppmv and 500 
ppmv, respectively.
    c. How Is the Oxygen Correction Factor Adjusted during Startup and 
Shutdown? You must identify in your Startup Shutdown, and Malfunction 
Plan a projected oxygen correction factor to use during periods of 
startup and shutdown. The projected oxygen correction factor should be 
based on normal operations. See Sec. 63.1206(c)(2)(iii). The rule 
provides this requirement because the oxygen concentration in the 
combustor can exceed 15% during startup and shutdown, causing the 
correction factor to increase exponentially from the normal value. Such 
large correction factors result in corrected carbon

[[Page 52950]]

monoxide and hydrocarbon levels that are inappropriately inflated.
5. What Are the Operating Parameter Limits for Hydrochloric Acid/
Chlorine Gas?
    You must maintain compliance with the hydrochloric acid/chlorine 
gas emission standard by establishing and complying with limits on 
operating parameters. See Sec. 63.1209(o). The following table 
summarizes these operating parameter limits. All sources must comply 
with the maximum chlorine feedrate limit. Other operating parameter 
limits apply depending on the type of hydrochloric acid/chlorine gas 
emission control device you use.

BILLING CODE 6560-50-P

[[Page 52951]]

[GRAPHIC] [TIFF OMITTED] TR30SE99.004



BILLING CODE 6560-50-C

[[Page 52952]]

    Hydrochloric acid/chlorine gas emissions from hazardous waste 
combustors are controlled by controlling the feedrate of total chlorine 
(organic and inorganic) and either wet or dry scrubbers. We discuss 
below the operating parameter limits that apply to each control 
technique.
    a. Maximum Chlorine Feedrate Limit. As proposed, you must establish 
a limit on the maximum feedrate of chlorine, both organic and 
inorganic, from all feedstreams based on levels fed during the 
comprehensive performance test. Chlorine feedrate is an important 
emission control technique because the amount of chlorine fed into a 
combustor directly affects emissions of hydrochloric acid/chlorine gas. 
To establish and comply with the feedrate limit, you must sample and 
analyze, and continuously monitor the flowrate, of all feedstreams 
(including hazardous waste, raw materials, and other fuels and 
additives) except natural gas, process air, and feedstreams from vapor 
recovery systems for chlorine content.244 Also as proposed, 
you must establish a maximum 12-hour rolling average feedrate limit 
based on operations during the comprehensive performance test as the 
average of the test run averages.
---------------------------------------------------------------------------

    \244\ See discussion in Section VII.D.3 above in the text for 
the rationale for exempting these feedstreams for monitoring for 
chlorine content.
---------------------------------------------------------------------------

    One commenter states that a chlorine feedrate is not necessary for 
cement kilns because cement kilns have an inherent incentive to control 
chlorine feedrates: to avoid operational problems such as the formation 
of material rings in the kiln or alkali-chloride condensation on the 
walls. Although we understand that cement kilns must monitor chlorine 
feedrates for operational reasons, several cement kilns in our data 
base emit levels of hydrochloric acid/chlorine gas at levels above 
today's emissions standard. We conclude, therefore, that the 
operational incentive to limit chlorine feedrates is not adequate to 
ensure compliance with the hydrochloric acid/chlorine gas emission 
standard.
    b. Wet Scrubbers. If your combustor is equipped with a wet 
scrubber, you must establish, continuously monitor, and comply with 
limits on the following operating parameters:
    i. Maximum Flue Gas Flowrate or Kiln Production Rate. As proposed, 
you must establish a limit on maximum flue gas flowrate or kiln 
production rate as a surrogate. See 61 FR at 17433. Gas flowrate is a 
key parameter affecting the control efficiency of a wet scrubber (and 
any emissions control device). As gas flowrate increases, control 
efficiency generally decreases unless other operating parameters are 
adjusted to accommodate the increased flowrate. Cement kilns and 
lightweight aggregate kilns may establish a limit on maximum production 
rate (e.g., raw material feedrate or clinker or aggregate production 
rate) in lieu of a maximum gas flowrate given that production rate 
directly relates to flue gas flowrate.
    As proposed, you must establish a maximum gas flowrate or 
production rate limit as the average of the maximum hourly rolling 
averages for each run of the comprehensive performance test.
    We did not receive adverse comment on this compliance parameter.
    ii. Minimum Pressure Drop Across the Scrubber. You must establish a 
limit on minimum pressure drop across the scrubber. If your combustor 
is equipped with a high energy scrubber (e.g., venturi, calvert), you 
must establish an hourly rolling average limits based on operations 
during the comprehensive performance test. The hourly rolling average 
is established as the average of the test run averages.
    If your combustor is equipped with a low energy scrubber (e.g., 
spray tower), you must establish a limit on minimum pressure drop based 
on the manufacturer's specification. You must comply with the limit on 
an hourly rolling average basis.
    Pressure drop across a wet scrubber is an important operating 
parameter because it is an indicator of good mixing of the two fluids, 
the scrubber liquid and the flue gas. A low pressure drop indicates 
poor mixing and, hence, poor efficiency. A high pressure drop indicates 
good removal efficiency.
    One commenter states that wet scrubber pressure drop is not an 
important parameter for packed-bed, low energy wet scrubbers. The 
commenter states that the performance of a packed-bed scrubber is based 
on good liquid-to-gas contacting. Thus, performance is dependent on 
packing design and scrubber fluid flow. In addition, the commenter 
states that scrubber liquid flow rate (and recirculation rate and make-
up water flow rate) are adequate for assuring proper scrubber 
operation. We note that for many types of low energy wet scrubbers, 
pressure drop can be a rough indicator of scrubber liquid and flue gas 
contacting. Thus, although it is not a critical parameter, the minimum 
pressure drop of a low energy scrubber should still be monitored and 
complied with on a continuous basis.
    Because pressure drop for a low energy scrubber (e.g., spray 
towers, packed beds, or tray towers) is not as important as for a high 
energy scrubber to maintain performance, however, the rule requires you 
to establish a limit on the minimum pressure drop for a low energy 
scrubber based on manufacturer specifications, rather than levels 
demonstrated during compliance testing. You must comply with this limit 
on an hourly rolling average basis. The pressure drop for high energy 
wet scrubbers, such as venturi or calvert scrubbers, however, is a key 
operating parameter to ensure the scrubber maintains performance. 
Accordingly, you must base the minimum pressure drop for these devices 
on levels achieved during the comprehensive test, and you must 
establish an hourly rolling average limit.
    iii. Minimum Liquid Feed Pressure. You must establish a limit on 
minimum liquid feed pressure to a low energy scrubber. The limit must 
be based on manufacturer's specifications and you must comply with it 
on an hourly rolling average basis.
    The rule requires a limit on liquid feed pressure because the 
removal efficiency of a low energy wet scrubber can be directly 
affected by the atomization efficiency of the scrubber. A drop in 
liquid feed pressure may be an indicator of poor atomization and poor 
scrubber removal efficiency. We are not requiring a limit on minimum 
liquid feed pressure for high energy scrubbers because liquid flow rate 
rather than feed pressure is the dominant operating parameter for high 
energy scrubbers.
    We acknowledge, however, that not all wet scrubbers rely on 
atomization efficiency to maintain performance. If manufacturer's 
specifications indicate that atomization efficiency is not an important 
parameter that controls the efficiency of your scrubber, you may 
petition permitting officials under Sec. 63.1209(g)(1) to waive this 
operating parameter limit.
    iv. Minimum Liquid pH. You must establish dual ten-minute and 
hourly rolling average limits on minimum pH of the scrubber water based 
on operations during the comprehensive performance test. The hourly 
rolling average is established as the average of the test run averages.
    The pH of the scrubber liquid is an important operating parameter 
because, at low pH, the scrubber solution is more acidic and removal 
efficiency of hydrochloric acid and chlorine gas decreases.
    These requirements, except for the proposed ten-minute averaging 
period, are the same as we proposed. See 61 FR at 17433. We did not 
receive adverse comments.

[[Page 52953]]

    v. Minimum Scrubber Liquid Flowrate or Minimum Liquid/Gas Ratio. 
You must establish an hourly rolling average limits on either minimum 
scrubber liquid flowrate and maximum flue gas flowrate or minimum 
liquid/gas ratio based on operations during the comprehensive 
performance test. The hourly rolling average is established as the 
average of the test run averages.
    Liquid flowrate and flue gas flowrate or liquid/gas ratio are 
important operating parameters because a high liquid-to-gas-flowrate 
ratio is indicative of good removal efficiency.
    We had proposed to limit the liquid-to-gas ratio only. Commenters 
suggest that a limit on liquid-to-gas flow ratio would not be needed if 
the liquid flowrate and flue gas flowrate were limited instead. They 
reason that, because gas flowrate is already limited, limiting liquid 
flowrate as well would ensure that the liquid-to-gas ratio is 
maintained. We agree. During normal operations, the liquid flowrate can 
only be higher than levels during the performance test, and gas 
flowrate can only be lower than during the performance test. Thus, the 
numerator in the liquid flowrate/gas flowrate ratio could only be 
larger, and the denominator could only be smaller. Consequently, the 
liquid flowrate/gas flowrate during normal operations will always be 
higher than during the comprehensive performance test. Consequently, we 
agree that a limit on liquid-to-gas-ratio is not needed if you 
establish a limit on liquid flowrate and flue gas flowrate. 
Establishing limits on these parameters is adequate to ensure that the 
liquid flowrate/gas ratio is maintained.245
---------------------------------------------------------------------------

    \245\ In fact, complying with limits on liquid flowrate and gas 
flowrate, rather than complying with a liquid flowrate/gas flowrate 
ratio, is a more conservative approach to ensure that the 
performance test ratio is maintained (at a minimum). Thus, we prefer 
that you establish a limit on liquid flowrate (in conjunction with 
the limit gas flowrate) in lieu of a limit on the ratio.
---------------------------------------------------------------------------

    c. Dry Scrubbers. A dry scrubber removes hydrochloric acid from the 
flue gas by adsorbing the hydrochloric acid onto sorbent, normally an 
alkaline substance like limestone. As proposed, if your combustor is 
equipped with a dry scrubber, you must establish, continuously monitor, 
and comply with limits on the following operating parameters: Gas 
flowrate or kiln production rate; sorbent feedrate; carrier fluid 
flowrate or nozzle pressure drop; and sorbent specifications. See 61 FR 
at 17434.
    i. Maximum Flue Gas Flowrate or Kiln Production Rate. As proposed, 
you must establish a limit on maximum flue gas flowrate or kiln 
production rate as a surrogate. The limit is established and monitored 
as discussed above for wet scrubbers.
    ii. Minimum Sorbent Feedrate. You must establish an hourly rolling 
average limit on minimum sorbent feedrate based on feedrate levels 
during the comprehensive performance test. The hourly rolling average 
is established as the average of the test run averages.
    Sorbent feedrate is important because, as more sorbent is fed into 
the dry scrubber, removal efficiency of hydrochloric acid and chlorine 
gas increases.246 Conversely, lower sorbent feedrates tend 
to cause removal efficiency to decrease.
---------------------------------------------------------------------------

    \246\ We note that sorbent should be fed to a dry scrubber in 
excess of the stoichiometric requirements for neutralizing the anion 
component in the flue gas. Lower levels of sorbent, even above 
stoichiometric requirements, would limit the removal of acid gasses.
---------------------------------------------------------------------------

    At proposal, we invited comment on whether a ten-minute rolling 
average is appropriate for sorbent feedrate (61 FR at 17434). We were 
concerned that some facilities may not automate their dry scrubbers to 
add sorbent solutions but instead add batches of virgin sorbent 
solution. Thus, we were concerned that a ten-minute rolling average may 
not be practicable in all cases. Some commenters are concerned that a 
ten-minute limit would be difficult to measure, especially in the case 
of batch addition of sorbent. Nonetheless, we have determined upon 
reanalysis that sorbent is not injected into the flue gas in 
``batches.'' Although sorbent may be added in batches to storage or 
mixing vessels, it must be injected into the flue gas continuously to 
provide continuous and effective removal of acid gases. Thus, ten-
minute rolling average limits would be practicable and appropriate for 
sorbent injection feedrates if ten-minute averages were required in 
this final rule.247 However, as discussed in Part Five, 
Section VII.B, we have decided to not require ten-minute averaging 
periods on a national basis. Permitting officials may, however, 
determine that shorter averaging periods are needed to better assure 
compliance with the emission standard.
---------------------------------------------------------------------------

    \247\ We note that flowrate measurement devices are available 
for ten-minute average times (e.g., those based on volumetric screw 
feeders which provide instantaneous measurements).
---------------------------------------------------------------------------

    iii. Minimum Carrier Fluid Flowrate or Nozzle Pressure Drop. A 
carrier fluid, normally air or water, is necessary to transport and 
inject the sorbent into the gas stream. As proposed, you must establish 
and continuously monitor a limit on either minimum carrier gas or water 
flowrate or pressure drop across the nozzle to ensure that the flow and 
dispersion of the injected sorbent into the flue gas stream is 
maintained. You must base the limit on manufacturer's specifications, 
and comply with the limit on a one-hour rolling average basis.
    Without proper carrier flow to the dry scrubber, the sorbent flow 
into the scrubber will decrease causing the efficiency to decrease. 
Nozzle pressure drop is also an indicator of carrier gas flow into the 
scrubber. At higher pressure drops, more sorbent is carried to the dry 
scrubber.
    iv. Identification of Sorbent Brand and Type or Adsorption 
Properties. You must either identify the sorbent brand and type used 
during the comprehensive performance test and continue using that 
sorbent, or identify the adsorption properties of that sorbent and use 
a sorbent having equivalent or better properties. This will ensure that 
the sorbent's adsorption properties are maintained.
    We proposed to require sources to continue to use the same sorbent 
brand and type as they used during the comprehensive performance test 
or obtain a waiver from this requirement from the Administrator. See 61 
FR at 17434. As discussed above in the context of specifying the brand 
of carbon used in carbon injection systems to control dioxin/furan, we 
have determined that sources should have the option of using 
manufacturer's specifications to specify the sorption properties of the 
sorbent used during the comprehensive performance test. You may use 
sorbent of other brands or types provided that it has equivalent or 
better sorption properties. You must include in the operating record 
written documentation that the substitute sorbent will provide the same 
level of control as the original sorbent.
6. What Are the Operating Parameter Limits for Particulate Matter?
    You must maintain compliance with the particulate matter emission 
standard by establishing and complying with limits on operating 
parameters. See Sec. 63.1209(m). The following table summarizes these 
operating parameter limits. All incinerators must comply with the limit 
on maximum ash feedrate. Other operating parameter limits apply 
depending on the type of particulate matter control device you use.

BILLING CODE 6560-50-P

[[Page 52954]]

[GRAPHIC] [TIFF OMITTED] TR30SE99.005



BILLING CODE 6560-50-C

[[Page 52955]]

    Particulate matter emissions from hazardous waste combustors are 
controlled by controlling the feedrate of ash to incinerators and using 
a particulate matter control device. We discuss below the operating 
parameter limits that apply to each control technique.
    a. Maximum Ash Feedrate. As proposed, if you own or operate an 
incinerator, you must establish a limit on the maximum feedrate of ash 
from all feedstreams based on the levels fed during the comprehensive 
performance test. To establish and comply with the feedrate limit, you 
must sample and analyze, and continuously monitor the flowrate of all 
feedstreams (including hazardous waste, and other fuels and additives) 
except natural gas, process air, and feedstreams from vapor recovery 
systems for ash content.248 Also as proposed, you must 
establish a maximum 12-hour rolling average feedrate limit based on 
operations during the comprehensive performance test as the average of 
the test run averages. See 61 FR at 17438.
---------------------------------------------------------------------------

    \248\ See discussion in Section VII.D.3 above in the text for 
the rationale for exempting these feedstreams from monitoring for 
ash content.
---------------------------------------------------------------------------

    Ash feedrate for incinerators is an important particulate matter 
control parameter because ash feedrates can relate directly to 
emissions of particulate matter (i.e., ash contributes to particulate 
matter in flue gas). We are not requiring an ash feedrate limit for 
cement or lightweight aggregate kilns because particulate matter from 
those combustors is dominated by raw materials entrained in the flue 
gas. The contribution to particulate matter of ash from hazardous waste 
or other feedstreams is not significant. We discussed this issue at 
proposal.
    A commenter states that ash feedrate limits are not needed for 
combustors using fabric filters, suggesting that fabric filter pressure 
drop and opacity monitoring are sufficient for compliance assurance. We 
discuss previously in this section (i.e., Part Five, Section VII) our 
concern that neither opacity monitors, nor limits on control device 
operating parameter, nor limits on the feedrates of constituents that 
can contribute directly to emissions of hazardous air pollutants 
comprise an ideal compliance assurance regime. We would prefer the use 
of a particulate matter CEMS for compliance assurance but cannot 
achieve that goal at this time. Absent the use of a CEMS and given the 
limitations of the individual compliance tools currently available, we 
are reluctant to forgo on a national, generic basis requiring limits on 
an operating parameter such as ash feedrate that we know can relate 
directly to particulate emissions. However, you may petition permitting 
officials under Sec. 63.1209(g)(1) for approval to waive the ash 
feedrate limit based on data or information documenting that pressure 
drop across the fabric filter coupled with an opacity monitor would 
provide equivalent or better compliance assurance than a limit on ash 
feedrate.
    b. Wet Scrubbers. As proposed, if your combustor is equipped with a 
wet scrubber, you must establish, continuously monitor, and comply with 
limits on the operating parameters discussed below. High energy wet 
scrubbers (e.g., venturi, calvert) remove particulate matter by 
capturing particles in liquid droplets and separating the droplets from 
the gas stream. Ionizing wet scrubbers use both an electrical charge 
and wet scrubbing to remove particulate matter. Low energy wet 
scrubbers that are not ionizing wet scrubbers (e.g., packed bed, spray 
tower) are only subject to the scrubber water solids content operating 
parameter requirements for particulate matter control because they are 
primarily used to control emissions of acid gases and only provide 
incidental particulate matter control.
    i. Maximum Flue Gas Flowrate or Kiln Production Rate. For high 
energy and ionic wet scrubbers, you must establish a limit on maximum 
flue gas flowrate or kiln production rate as a surrogate. See 61 FR at 
17438. Gas flowrate is a key parameter affecting the control efficiency 
of a wet scrubber (and any emissions control device). As gas flowrate 
increases, control efficiency generally decreases unless other 
operating parameters are adjusted to accommodate the increased 
flowrate. Cement kilns and lightweight aggregate kilns may establish a 
limit on maximum production rate (e.g., raw material feedrate or 
clinker or aggregate production rate) in lieu of a maximum gas flowrate 
given that production rate directly relates to flue gas flowrate.
    As proposed, you must establish a maximum gas flowrate or 
production rate limit as the average of the maximum hourly rolling 
averages for each run of the comprehensive performance test.
    ii. Minimum Pressure Drop Across the Scrubber. For high energy 
scrubbers only, you must establish an hourly rolling average limits on 
minimum pressure drop across the scrubber based on operations during 
the comprehensive performance test. The hourly rolling average is 
established as the average of the test run averages. See the discussion 
in Section VII.D.5.b above for a discussion on the approach for 
calculating limits from comprehensive performance test data.
    iii. Minimum Scrubber Liquid Flowrate or Minimum Liquid/Gas Ratio. 
For high energy wet scrubbers, you must establish an hourly rolling 
average limits on either minimum scrubber liquid flowrate and maximum 
flue gas flowrate or minimum liquid/gas ratio based on operations 
during the comprehensive performance test. The hourly rolling average 
is established as the average of the test run averages. See the 
discussion in Section VII.D.5.b above for a discussion on the approach 
for calculating limits from comprehensive performance test data.
    iv. Maximum Solids Content of Scrubber Water or Minimum Blowdown 
Rate Plus Minimum Scrubber Tank Volume or Level. For all wet scrubbers, 
to maintain the solids content of the scrubber water to levels no 
higher than during the comprehensive performance test, you must 
establish a limit on either: (1) Maximum solids content of the scrubber 
water; or (2) minimum blowdown rate plus minimum scrubber tank volume 
or level. If you elect to establish a limit on maximum solids content 
of the scrubber water, you must comply with the limit either by: (1) 
Continuously monitoring the solids content and establishing 12-hour 
rolling average limits based on solids content during the comprehensive 
performance test; or (2) periodic manual sampling and analysis of 
scrubber water for solids content. Under option 1, the 12-hour rolling 
average is established as the average of the test run averages. Under 
option 2, you must either comply with a default sampling and analysis 
frequency for scrubber water solids content of once per hour or 
recommend an alternative frequency in your comprehensive performance 
test plan that you submit for review and approval.
    Solids content in the scrubber water is an important operating 
parameter because as the solids content increases, particulate 
emissions increase. This is attributable to evaporation of scrubber 
water and release of previously captured particulate back into the flue 
gas. Blowdown is the amount of scrubber liquid removed from the process 
and not recycled back into the wet scrubber. As scrubber liquid is 
removed and not recycled, solids are removed. Thus, blowdown is an 
operating parameter that affects solids content and can be used as a 
surrogate for measuring solids content directly. See 61 FR 17438.
    The proposed rule would have required continuously monitored limits 
on either minimum blowdown or a

[[Page 52956]]

maximum solids content. In response to comments and upon reanalysis of 
the issues, we conclude that we need to make two revisions to these 
requirements. First, we are concerned that it may be problematic to 
continuously monitor the solids content of scrubber water. 
Consequently, we revised the requirements to allow manual sampling and 
analysis on an hourly basis, unless you justify an alternative 
frequency. Second, we are concerned that a limit on blowdown rate 
without an associated limit on either minimum scrubber water tank 
volume or level would not be adequate to provide control of solids 
content. The solids concentration in blowdown tanks could be higher at 
lower water levels. Therefore, water levels need to be at least 
equivalent to the levels during the comprehensive performance test. 
This should not be a significant additional burden. Sources should be 
monitoring the water level in the scrubber water tank as a measure of 
good operating practices. Consequently, we revise the requirement to 
require a minimum tank volume or level in conjunction with a minimum 
blowdown rate for sources that elect to use that compliance option.
    c. Fabric Filter. If your combustor is equipped with a fabric 
filter, you must establish, continuously monitor, and comply with 
limits on the operating parameters discussed below.
    i. Maximum Flue Gas Flowrate or Kiln Production Rate. As proposed, 
you must establish a limit on maximum flue gas flowrate or kiln 
production rate as a surrogate. Gas flowrate is a key parameter 
affecting the control efficiency of a fabric filter (and any emissions 
control device). As gas flowrate increases, control efficiency 
generally decreases unless other operating parameters are adjusted to 
accommodate the increased flowrate. Cement kilns and lightweight 
aggregate kilns may establish a limit on maximum production rate (e.g., 
raw material feedrate or clinker or aggregate production rate) in lieu 
of a maximum gas flowrate given that production rate directly relates 
to flue gas flowrate.
    As proposed, you must establish a maximum gas flowrate or 
production rate limit as the average of the maximum hourly rolling 
averages for each run of the comprehensive performance test.
    ii. Minimum Pressure Drop and Maximum Pressure Drop Across the 
Fabric Filter. You must establish a limit on minimum pressure drop and 
maximum pressure drop across each cell of the fabric filter based on 
manufacturer's specifications.
    Filter failure is typically due to filter holes, bleed-through 
migration of particulate through the filter and cake, and small ``pin 
holes'' in the filter and cake. Because low pressure drop is an 
indicator of one of these types of failure, pressure drop across the 
fabric filter is an indicator of fabric filter failure.
    We had proposed to establish limits on minimum pressure drop based 
on the performance test. Commenters indicate, however, that maintaining 
a pressure drop not less than levels during the performance test will 
not ensure baghouse performance. We concur. The pressure change caused 
by fabric holes may not be measurable, especially at large sources with 
multiple chamber filter housing units that operate in parallel. In 
addition, operating at high pressure drop may not be desirable because 
high pressures can create pin holes.
    Nonetheless, establishing a limit on minimum pressure drop based on 
manufacturer's recommendations, as suggested by a commenter, is a 
reasonable and prudent approach to help ensure fabric filter 
performance. We have since determined that an operating parameter limit 
for maximum pressure drop across each cell of the fabric filter, based 
on manufacturer specifications, is also necessary. As discussed above, 
a high pressure drop in a cell of a fabric filter may cause small 
pinholes to form or may be indicative of bag blinding or plugging, 
which could result in increased particulate emissions. We do not 
consider this additional provision to be burdensome, especially because 
both the maximum and minimum pressure drop limits are based on 
manufacturer specifications on an hourly rolling average. These 
pressure drop monitoring requirements, in combination with COMS for 
cement kilns and bag leak detection systems for incinerators and 
lightweight aggregate kilns, provide a significant measure of assurance 
that control performance is maintained.
    d. Electrostatic Precipitators and Ionizing Wet Scrubbers. As 
proposed, if your combustor is equipped with an electrostatic 
precipitator or ionizing wet scrubber, you must establish, continuously 
monitor, and comply with limits on the operating parameters discussed 
below.
    i. Maximum Flue Gas Flowrate or Kiln Production Rate. You must 
establish a limit on maximum flue gas flowrate or kiln production rate 
as a surrogate. Gas flowrate is a key parameter affecting the control 
efficiency of an emissions control device. As gas flowrate increases, 
control efficiency generally decreases unless other operating 
parameters are adjusted to accommodate the increased flowrate. Cement 
kilns and lightweight aggregate kilns may establish a limit on maximum 
production rate (e.g., raw material feedrate or clinker or aggregate 
production rate) in lieu of a maximum gas flowrate given that 
production rate directly relates to flue gas flowrate.
    As proposed, you must establish a maximum gas flowrate or 
production rate limit as the average of the maximum hourly rolling 
averages for each run of the comprehensive performance test.
    ii. Minimum Secondary Power Input to Each Field. You must establish 
an hourly rolling average limit on minimum secondary power (kVA) input 
to each field of the electrostatic precipitator or ionizing wet 
scrubber based on operations during the comprehensive performance test. 
The hourly rolling average is established as the average of the test 
run averages.
    Electrostatic precipitators capture particulate matter by charging 
the particulate in an electric field and collecting the charged 
particulate on an inversely charged collection plate. Higher voltages 
improve magnetic field strength, resulting in charged particle 
migration to the collection plate. High current leads to an increased 
particle charging rate and increased electric field strength near the 
collection electrode, increasing collection at the plate, as well. 
Therefore, maximizing both voltage and current by specifying minimum 
power input to the electrostatic precipitator is desirable for good 
particulate matter collection in electrostatic precipitators. For these 
reasons, the rule requires you to monitor power input to each field of 
the electrostatic precipitator to ensure that collection efficiency is 
maintained at performance test levels.
    Power input to an ionizing wet scrubber is important because it 
directly affects particulate removal. Ionizing wet scrubbers charge the 
particulate prior to it entering a packed bed wet scrubber. The 
charging aids in the collection of the particulate onto the packing 
surface in the bed. The particulate is then washed off the packing by 
the scrubber liquid. Therefore, power input is a key parameter to 
proper operation of an ionizing wet scrubber.
    One commenter suggests that a minimum limit on electrostatic 
precipitator voltage be used instead of power input because, at low 
particulate matter loadings, operation at maximum power input is 
inefficient. Another commenter suggests that neither a limit on voltage 
or power input is appropriate because a minimum limit would

[[Page 52957]]

actually cause a potential decrease in operational efficiency (required 
power input and voltage are strong functions of gas and particulate 
characteristics, electrostatic precipitator arcing and sparking at high 
voltage and power requirements, etc.). Alternatively, they recommend 
that a limit on the minimum number of energized electrostatic 
precipitator fields be established. We continue to maintain that a 
minimum limit on power input to each field of the electrostatic 
precipitator is generally accepted as an appropriate parameter for 
assuring electrostatic precipitator performance. Consequently, it is an 
appropriate parameter for a generic, national standard. If you believe, 
however, that in your situation limits on alternative operating 
parameters may better assure that control performance is maintained you 
may request approval to use alternative monitoring approaches under 
Sec. 63.1209(1).
    Another commenter suggests that, in addition to a minimum power 
input for an ionizing wet scrubber, a limit should be set on the 
maximum time allowable to be below the minimum voltage. While feasible, 
we conclude that this limit is not necessary on a national basis 
because the one hour rolling average requirement limits the amount of 
time a source can operate below its minimum voltage limit. We 
acknowledge, however, that a permit writer may find it necessary to 
require shorter averaging periods (e.g., ten-minute or instantaneous 
limits) to better control the amount of time a source can operate at 
levels below its limit.
7. What Are the Operating Parameter Limits for Destruction and Removal 
Efficiency?
    You must establish, monitor, and comply with the same operating 
parameter limits to ensure compliance with the destruction and removal 
efficiency (DRE) standard as you establish to ensure good combustion 
practices are maintained for compliance with the dioxin/furan emission 
standard. See Sec. 63.1209(j) and the discussion in Section VII.D.1 
above. This is because compliance with the DRE standard is ensured by 
maintaining combustion efficiency using good combustion practices. 
Thus, the DRE operating parameters are: maximum waste feedrate for 
pumpable and nonpumpable wastes, minimum gas temperature for each 
combustion chamber, maximum gas flowrate or kiln production rate, and 
parameters that you recommend to ensure the operations of each 
hazardous waste firing system are maintained.249
---------------------------------------------------------------------------

    \249\ You are required to establish operating requirements only 
for hazardous waste firing systems because of DRE standard applies 
only to hazardous waste. Permitting officials may determine on a 
site-specific basis under authority of Sec. 63.1209(g)(2), however, 
that combustion of other fuels or wastes may affect your ability to 
maintain DRE for hazardous waste. Accordingly, permitting officials 
may define operating requirements for other (i.e., other than 
hazardous waste) waste or fuel firing systems. Permitting officials 
may also determine under that provision on a site-specific basis 
that operating requirements other than those prescribed for DRE (and 
good combustion practices) may be needed to ensure compliance with 
the DRE standard.
---------------------------------------------------------------------------

VIII. Which Methods Should Be Used for Manual Stack Tests and 
Feedstream Sampling and Analysis?

    This part discusses the manual stack test and the feedstream 
sampling and analysis methods required by today's rule.
A. Manual Stack Sampling Test Methods
    To demonstrate compliance with today's rule, you must use: (1) 
Method 0023A for dioxin and furans; (2) Method 29 for mercury, 
semivolatile metals, and low volatile metals; (3) Method 26A for 
hydrochloric acid and chlorine; and (4) Method 5 or 5i for particulate 
matter. These methods are found at 40 CFR part 60, appendix A, and in 
``Test Methods for Evaluating Solid Waste, Physical/Chemical Methods,'' 
EPA publication.
    In the NPRM, we proposed that BIF manual stack test methods 
currently located in SW-846 be required to demonstrate compliance with 
the proposed standards. Based on public comments from the proposal, in 
the December 1997 NODA we considered simply citing the ``Air Methods'' 
found in appendix A to part 60. Our rationale was that facilities may 
be required to perform two identical tests, one from SW-846 for 
compliance with MACT or RCRA and one from part 60, appendix A, for 
compliance with other air rules using identical test methods simply 
because one method is an SW-846 method and the other an Air Method. See 
62 FR at 67803. To facilitate compliance with all air emissions stack 
tests, we stated that we would list the methods found in 40 CFR part 
60, appendix A, as the stack test methods used to comply with the 
standards. Later in this section we present an exception for dioxin and 
furan testing.
    In today's rule, we adopt the approach of the December 1997 NODA 
and require that the test methods found in 40 CFR part 60, appendix A 
be used to demonstrate compliance with the emission standards of 
today's rule, except for dioxin and furan. Specifically, today's rule 
requires you to use Method 0023A in SW-846 for sampling dioxins and 
furans from stack emissions. As noted by commenters, improvements have 
been made to the dioxin and furan Method 0023A in the Third Update of 
SW-846 that have been previously incorporated into today's regulations. 
See the 40 CFR 63.1208(a), incorporation of SW-846 by reference. 
However, these have not yet been incorporated into 40 CFR part 60, 
Appendix A. To capture these improvements to the method, today's rule 
incorporates by reference SW-846 Method 0023A. We have evaluated both 
methods. Use of the improved Method 0023A will not affect the 
achievability of the dioxin and furan standard.
    In the proposal, we sought comment on the handling of nondetect 
values for congeners analyzed using the dioxin and furan method. We 
also sought comment on whether the final rule should specify minimum 
sampling times. We proposed allowing facilities to assume that 
emissions of dioxins and furans congeners are zero if the analysis 
showed a nondetect for that congener and the sample time for the test 
method run was at least 3 hours. See 61 FR 17378. Dioxin/furan results 
may not be blank corrected. We received several comments this proposed 
approach, which are summarized below.
    One commenter believes that a minimum dioxin/furan sampling time of 
two hours is sufficient. Another commenter believes that a minimum 
sample time as well as a minimum sample volume should be specified. 
Several commenters agree that nondetects should be treated as zero 
(which is consistent with the German standard) and prefer the three 
hour minimum sample period because this would help eliminate intra-
laboratory differences and difficulties with matrix effects in 
attaining low detection limits. One commenter believes that EPA should 
specify the required detection limit for each congener analysis, 
otherwise the provision to assign zeroes to nondetected congeners in 
the TEQ calculation is open to abuse and could result in an 
understatement of the true dioxin/furan emissions. This commenter also 
believes that a source should not be allowed to sample dioxin/furans 
for time periods less than three hours, even if they assume nondetects 
are present at the detection limit.
    Upon carefully considering all the above comments, we conclude that 
the following approach best addresses the nondetect issue. The final 
rule requires all sources to sample dioxin/furans for a minimum of 
three hours for each run,

[[Page 52958]]

and requires all sources to collect a flue gas sample of at least 2.5 
dscm. We conclude both these requirements are necessary to maintain 
consistency from source to source, and to better assure that the 
dioxin/furan emission results are accurate and representative. We 
conclude that these two requirements are achievable and appropriate 
250. These requirements are consistent with the requirements 
included in the proposed Portland Cement Kiln MACT rule (see 64 FR at 
31898). The final rule also allows a source to assume all nondetected 
congeners are not present in the emissions when calculating TEQ values 
for compliance purposes.
---------------------------------------------------------------------------

    \250\ See Final Technical Support Document, Volume IV, Chapter 
3, for further discussion.
---------------------------------------------------------------------------

    We considered whether it would be appropriate to specify required 
minimum detection limits for each congener analysis in order to better 
assure that sources achieved reasonable detection limits, as one 
commenter recommended. Such a requirement would prevent abuse and 
understatements of the true dioxin/furan emissions. We conclude, 
however, that it is not appropriate to finalize minimum detection 
limits in this rulemaking without giving the opportunity to all 
interested parties to review and comment on such an approach.
    However, we are concerned that (1) sources have no incentive to 
achieve low detection limits; and (2) sources may abuse the provision 
that allows nondetected congener results to be treated as if they were 
not present. As explained in the Final Technical Support Document 
referenced in the preceding paragraph, if one assumes that all dioxin/
furan congeners are present at what we consider to be poor detection 
limits using Method 23A, the resultant TEQ can approach the emission 
standard. This outcome is clearly inappropriate from a compliance 
perspective.
    As a result, we highly recommend that this issue be addressed in 
the review process of the performance test workplan. Facilities should 
submit information that describes the target detection limits for all 
congeners, and calculate a dioxin/furan TEQ concentration assuming all 
congeners are present at the detection limit (similar to what is done 
for risk assessments). If this value is close to the emission standard, 
both the source and the regulatory official should determine if it is 
appropriate to either sample for longer time periods or investigate 
whether it is possible to achieve lower detection limits by using 
different analytical procedures that are approved by the Agency.
    Also, EPA has developed analytical standards for certain mono-
through tri-chloro dioxin and furan congeners. We encourage you to test 
for these congeners in addition to the congeners that comprise today's 
standards. This can be done at very little increased cost. If you test 
for these additional congeners, please include the results in your 
Notification of Compliance. We would like this data so we can develop a 
database from which to determine which (if any) of these compounds can 
act as surrogate(s) for the dioxin and furan congeners which comprise 
the total and TEQ. If easily measurable surrogate(s) can be found, we 
can then start the development of a CEMS for these surrogates. A 
complete list of these congeners will be included in the implementation 
document for this rule and updated periodically through guidance.
    One commenter suggests that a source be allowed to conduct one 
extended dioxin/furan sampling event as opposed to three separate runs 
with three separate sampling trains because this would minimize the 
radioactive waste generated for sources that combust mixed waste. We 
conclude this issue should be handled on a site-specific basis, 
although an allowance of such an approach seems reasonable. A source 
can petition the Agency under the provisions of Sec. 63.7(f) for an 
alternative test method for such a site-specific determination.
    The final rule also adopts the approach discussed in the December 
1997 NODA for sampling of mercury, semi-volatile metals, and low-
volatile metals. Therefore, for stack sampling of mercury, semi-
volatile metals, and low-volatile metals, you are required to use 
Method 29 in 40 CFR part 60, appendix A. No adverse comments were 
received concerning this approach in the December 1997 NODA.
    For compliance with the hydrochloric acid and chlorine standards, 
today's rule requires that you use Method 26A in 40 CFR part 60, 
appendix A. Commenters state that we should instead require a method 
involving the Fourier Transform Infrared and Gas Filter Correlation 
Infrared instrumental techniques. Commenters contend that Method 26A is 
biased high at cement kilns because it collects ammonium chloride in 
addition to the hydrochloric acid and chlorine gas emissions it was 
designed to report. Commenters also indicate that the Fourier Transform 
Infrared and Gas Filter Correlation Infrared were validated against 
Method 26A and that these alternative methods do not bias the results 
high due to ammonium chloride 251. The data for today's 
hydrochloric acid standard was derived using the SW-846 equivalent to 
Method 26A (Method 0050) as the reference method. Therefore, today's 
standard accounts for the ammonium chloride collection bias. We reject 
the idea that we should require other methods. If the commenters are 
correct, other methods would not sample the ammonium chloride portion, 
thus making the standard less stringent. You can obtain Administrator 
approval for using Fourier Transform Infrared or Gas Filter Correlation 
Infrared techniques following the provisions found in 40 CFR 63.7 if 
those methods are found to pass a part 63, appendix A, Method 301 
validation at the source.
---------------------------------------------------------------------------

    \251\ After further review and consideration of the GFCIR Method 
(322), we will not be promulgating its use in the Portland Cement 
Kiln NESHAP rulemaking due to problems encountered with the method 
during emission testing at lime manufacturing plants.
---------------------------------------------------------------------------

    Compliance with the particulate matter standards requires the use 
of either Method 5 or Method 5i in 40 CFR part 60, appendix A. See a 
related discussion of Method 5i in Part 5, section VII.C.2.a of the 
preamble to today's rule. Although Method 5i has better precision than 
Method 5, your choice of methods depends on the emissions during the 
performance test. In cases of low levels of particulate matter (i.e., 
for total train catches of less than 50 mg), we prefer that Method 5i 
be used. For higher emissions, Method 5 may be used 252. In 
practice this will likely mean that all incinerators and most 
lightweight aggregate kilns will use Method 5i for compliance, while 
some lightweight aggregate kilns and most cement kilns will use Method 
5.
---------------------------------------------------------------------------

    \252\ We note that this total train catch is not intended to be 
a data acceptance criteria. Thus, total train catches exceeding 50 
mg do not invalidate the method.
---------------------------------------------------------------------------

    Today's rule also allows the use of any applicable SW-846 test 
methods to demonstrate compliance with requirements of this subpart. As 
an example, some commenters noted a preference to perform particulate 
matter and hydrochloric acid tests together using Method 0050. Today's 
rule would allow that practice. Applicable SW-846 test methods are 
incorporated for use into today's rule via reference. See section 
1208(a).
B. Sampling and Analysis of Feedstreams
    Today's rule does not require the use of SW-846 methods for the 
sampling and analysis of feedstreams. Consistent with our approach to 
move toward performance based measurement

[[Page 52959]]

 systems for other than method-defined parameters,253 
today's rule allows the use of any reliable analytical method to 
determine feedstream concentrations of metals, halogens, and other 
constituents. It is your responsibility to ensure that the sampling and 
analysis are unbiased, precise, and representative of the waste. For 
the waste, you must demonstrate that: (1) Each constituent of concern 
is not present above the specification level at the 80% upper 
confidence limit around the mean; and (2) the analysis could have 
detected the presence of the constituent at or below the specification 
level at the 80% upper confidence limit around the mean. You can refer 
to the Guidance for Data Quality Assessment--Practical Methods for Data 
Analysis, EPA QA/G-9, January 1998, EPA/600/R-96/084 for more 
information. Proper selection of an appropriate analytical method and 
analytical conditions (as allowed by the scope of that method) are 
demonstrated by adequate recovery of spiked analytes (or surrogate 
analytes) and reproducible results. Quality control data obtained must 
also reflect consistency with the data quality objectives and intent of 
the analysis. You can read the January 31, 1996, memorandum from Barnes 
Johnson, Director of the Economics, Methods, and Risk Assessment 
Division, to James Berlow, Director of the Hazardous Waste Minimization 
and Management Division for more information on this topic.
---------------------------------------------------------------------------

    \253\ Feedstream sampling and analysis are not method defined 
parameters.
---------------------------------------------------------------------------

IX. What Are the Reporting and Recordkeeping Requirements?

    We discuss in this section reporting and recordkeeping requirements 
and a provision in the rule for allowing data compression to reduce the 
recordkeeping burden.
A. What Are the Reporting Requirements?
    The reporting requirements of the rule include notifications and 
reports that must be submitted to the Administrator as well as 
notifications, requests, petitions, and applications that you must 
submit to the Administrator only if you elect to request approval to 
comply with certain reduced or alternative requirements. These 
reporting requirements are summarized in the following tables. We 
discuss previously in various sections of today's preamble the 
rationale for additional or revised reporting requirements to those 
currently required under subpart A of part 63 for all MACT sources. In 
other cases, the reporting requirements for hazardous waste combustors 
are the same as for other MACT sources (e.g., initial notification 
under existing Sec. 63.9(b). We also show in the tables the 
reference(s) in the regulations for the reporting requirement.

   Summary of Notifications That You Must Submit to the Administrator
------------------------------------------------------------------------
               Reference                           Notification
------------------------------------------------------------------------
63.9(b)................................  Initial notifications that you
                                          are subject to Subpart EEE.
63.1210(b) and (c).....................  Notification of intent to
                                          comply.
63.9(d)................................  Notification that you are
                                          subject to special compliance
                                          requirements.
63.1207(e), 63.9(e) 63.9(g) (1) and (3)  Notification of performance
                                          test and continuous monitoring
                                          system evaluation, including
                                          the performance test plan and
                                          CMS performance evaluation
                                          plan.
163.1210(d), 63.1207(j), 63.9(h),        Notification of compliance,
 63.10(d)(2), 63.10(e)(2).                including results of
                                          performance tests and
                                          continuous monitoring system
                                          performance evaluations.
63.1206(b)(6)..........................  Notification of changes in
                                          design, operation, or
                                          maintenance.
63.9(j)................................  Notification and documentation
                                          of any change in information
                                          already provided under Sec.
                                          63.9.
------------------------------------------------------------------------
\1\ You may also be required on a case-by-case basis to submit a
  feedstream analysis plan under Sec.  63.1209(c)(3).


      Summary of Reports That You Must Submit to the Administrator
------------------------------------------------------------------------
               Reference                              Report
------------------------------------------------------------------------
63.1211(b).............................  Compliance progress report
                                          associated and submitted with
                                          the notification of intent to
                                          comply.
63.10(d)(4)............................  Compliance progress reports, if
                                          required as a condition of an
                                          extension of the compliance
                                          date granted under Sec.
                                          63.6(i).
63.1206(c)(3)(vi)......................  Excessive exceedances reports.
63.1206(c)(4)(iv)......................  Emergency safety vent opening
                                          reports.
63.10(d)(5)(i).........................  Periodic startup, shutdown, and
                                          malfunction reports.
63.10(d)(5)(ii)........................  Immediate startup, shutdown,
                                          and malfunction reports.
63.10(e)(3)............................  Excessive emissions and
                                          continuous monitoring system
                                          performance report and summary
                                          report.
------------------------------------------------------------------------


Summary of Notifications, Requests, Petitions, and Applications That You
    Must Submit to the Administrator Only if You Elect To Comply With
                   Reduced or Alternative Requirements
------------------------------------------------------------------------
                                              Notification, request,
               Reference                     petition, or application
------------------------------------------------------------------------
63.1206(b)(5), 63.1213, 63.6(i),         You may request an extension of
 63.9(c).                                 the compliance date for up to
                                          one year.
63.9(i)................................  You may request an adjustment
                                          to time periods or postmark
                                          deadlines for submittal and
                                          review of required
                                          information.
63.1209(g)(1)..........................  You may request approval of:
                                          (1) alternative monitoring
                                          methods, except for standards
                                          that you must monitor with a
                                          continuous emission monitoring
                                          system (CEMS) and except for
                                          requests to use a CEMS in lieu
                                          of operating parameter limits;
                                          or (2) a waiver of an
                                          operating parameter limit.
63.1209(a)(5), 63.8(f).................  You may request: (1) approval
                                          of alternative monitoring
                                          methods for compliance with
                                          standards that are monitored
                                          with a CEMS; and (2) approval
                                          to use a CEMS in lieu of
                                          operating parameter limits.

[[Page 52960]]

 
63.1204(d)(4)..........................  Notification that you elect to
                                          comply with the emission
                                          averaging requirements for
                                          cement kilns with in-line raw
                                          mills.
63.1204(e)(4)..........................  Notification that you elect to
                                          comply with the emission
                                          averaging requirements for
                                          preheater or preheater/
                                          precalciner kilns with dual
                                          stacks.
63.1206(b)(1)(ii)(A)...................  Notification that you elect to
                                          document compliance with all
                                          applicable requirements and
                                          standards promulgated under
                                          authority of the Clean Air
                                          Act, including Sections 112
                                          and 129, in lieu of the
                                          requirements of Subpart EEE
                                          when not burning hazardous
                                          waste.
63.1206(b)(9)(iii)(B)..................  If you elect to conduct
                                          particulate matter CEMS
                                          correlation testing and wish
                                          to have federal particulate
                                          matter and opacity standards
                                          and associated operating
                                          limits waived during the
                                          testing, you must notify the
                                          Administrator by submitting
                                          the correlation test plan for
                                          review and approval.
63.1206(b)(10).........................  Owners and operators of
                                          lightweight aggregate kilns
                                          may request approval of
                                          alternative emission standards
                                          for mercury, semivolatile
                                          metal, low volatile metal, and
                                          hydrochloric acid/chlorine gas
                                          under certain conditions.
63.1206(b)(11).........................  Owners and operators of cement
                                          kilns may request approval of
                                          alternative emission standards
                                          for mercury, semivolatile
                                          metal, low volatile metal, and
                                          hydrochloric acid/chlorine gas
                                          under certain conditions.
63.1207(c)(2)..........................  You may request to base initial
                                          compliance on data in lieu of
                                          a comprehensive performance
                                          test.
63.1207(i).............................  You may request up to a one-
                                          year time extension for
                                          conducting a performance test
                                          (other than the initial
                                          comprehensive performance
                                          test) to consolidate testing
                                          with other state or federally-
                                          required testing.
63.1209(l)(1)..........................  You may request to extrapolate
                                          mercury feedrate limits.
63.1209(n)(2)(ii)......................  You may request to extrapolate
                                          semivolatile and low volatile
                                          metal feedrate limits.
63.10(e)(3)(ii)........................  You may request to reduce the
                                          frequency of excess emissions
                                          and CMS performance reports.
63.10(f)...............................  You may request to waive
                                          recordkeeping or reporting
                                          requirements.
63.1211(e).............................  You may request to use data
                                          compression techniques to
                                          record data on a less frequent
                                          basis than required by Sec.
                                          63.1209.
------------------------------------------------------------------------

    Some commenters suggest that the rule needs to provide additional 
reporting of information regarding metals fed to cement kilns, 
including quarterly reporting of daily average metal feedrates, maximum 
hourly feedrates, and all testing and analytical information on the 
toxic metal content of cement kiln dust and clinker product. Also, they 
suggest that toxic metals that are Toxics Release Inventory pollutants 
and that are released to the land from cement kiln dust disposal should 
be reported. While these reports might have some value for other 
purposes, we must carefully scrutinize all reporting and recordkeeping 
burdens for a rulemaking and determine whether the reporting and 
recordkeeping requirements are necessary to ensure compliance with the 
standards. (We, as an agency, cannot increase overall our reporting and 
recordkeeping burden.)
    We do not believe that these reports are needed to ensure 
compliance with the standards and therefore are not requiring them. On 
balance, quarterly filing requirements would be too burdensome. A 
source must document compliance with all operating parameter limits and 
emission standards at all times, and its records are subject to 
inspection at any time. There is no additional need to provide 
quarterly reports.
    One commenter suggests that the proposed rule incorrectly focuses 
on maximizing data collection as opposed to ensuring performance, thus 
frustrating the use of better technology and methods. We, of course, 
are also interested in ensuring performance by all reasonable means, 
which for example accounts for our continued focus on continuous 
emission monitors. However, we are not able to sacrifice data 
collection as a means for ensuring compliance as well as a means to 
undergird future rulemakings, assess achievability, and determine site-
specific compliance limits, where necessary.
B. What Are the Recordkeeping Requirements?
    You must keep the records summarized in the table below for at 
least five years from the date of each occurrence, measurement, 
maintenance, corrective action, report, or record. See existing 
Sec. 63.10(b)(1). At a minimum, you must retain the most recent two 
years of data on site. You may retain the remaining three years of data 
off site. You may maintain such files on: microfilm, a computer, 
computer floppy disks, optical disk, magnetic tape, or microfiche.
    We discuss previously in various sections of today's preamble the 
rationale for additional or revised recordkeeping requirements to those 
currently required under subpart A of part 63 for all MACT sources. In 
other cases, the recordkeeping requirements for hazardous waste 
combustors are the same as for other MACT sources (e.g., record of the 
occurrence and duration of each malfunction of the air pollution 
control equipment; see existing Sec. 63.10(b)(2)(ii)). We also show in 
the table the reference(s) in the regulations for the recordkeeping 
requirement.

[[Page 52961]]



Summary of Documents, Data, and Information That You Must Include in the
                            Operating Record
------------------------------------------------------------------------
               Reference                  Document, data, or information
------------------------------------------------------------------------
63.1201(a), 63.10 (b) and (c)..........  General. Information required
                                          to document and maintain
                                          compliance with the
                                          regulations of Subpart EEE,
                                          including data recorded by
                                          continuous monitoring systems
                                          (CMS), and copies of all
                                          notifications, reports, plans,
                                          and other documents submitted
                                          to the Administrator.
63.1211(d).............................  Documentation of compliance.
63.1206 (c)(3)(vii)....................  Documentation and results of
                                          the automatic waste feed
                                          cutoff operability testing.
63.1209 (c)(2).........................  Feedstream analysis plan.
63.1204 (d)(3).........................  Documentation of compliance
                                          with the emission averaging
                                          requirements for cement kilns
                                          with in-line raw mills.
63.1204 (e)(3).........................  Documentation of compliance
                                          with the emission averaging
                                          requirements for preheater or
                                          preheater/precalciner kilns
                                          with dual stacks.
63.1206(b)(1) (ii)(B)..................  If you elect to comply with all
                                          applicable requirements and
                                          standards promulgated under
                                          authority of the Clean Air
                                          Act, including Sections 112
                                          and 129, in lieu of the
                                          requirements of Subpart EEE
                                          when not burning hazardous
                                          waste, you must document in
                                          the operating record that you
                                          are in compliance with those
                                          requirements.
63.1206 (c)(2).........................  Startup, shutdown, and
                                          malfunction plan.
63.1206(c) (3)(v)......................  Corrective measures for any
                                          automatic waste feed cutoff
                                          that results in an exceedance
                                          of an emission standard or
                                          operating parameter limit.
63.1206(c) (4)(ii).....................  Emergency safety vent operating
                                          plan.
63.1206 (c)(4)(iii)....................  Corrective measures for any
                                          emergency safety vent opening.
63.1206 (c)(6).........................  Operator training and
                                          certification program.
63.1209 (k)(6)(iii), 63.1209             Documentation that a substitute
 (k)(7)(ii), 63.1209 (k)(9)(ii),          activated carbon, dioxin/furan
 63.1209 (o)(4)(iii).                     formation reaction inhibitor,
                                          or dry scrubber sorbent will
                                          provide the same level of
                                          control as the original
                                          material.
------------------------------------------------------------------------

    Some commenters are concerned that the specification of media on 
which these files may be maintained unnecessarily limits the options to 
facilities, especially those not equipped with computer or other 
electronic data gathering equipment. We conclude, however, that the 
options listed under Sec. 63.10(b)(1) seem to provide the greatest 
flexibility possible, including the reasonable management of paper 
records through the use of microfilm or microfiche. We encourage the 
use of computer and electronic equipment, however, for logistical 
reasons (retrieval and inspection can be easier) and as a means to 
enhance dissemination to the local community to foster an atmosphere of 
full and open disclosure about facility operations.
C. How Can You Receive Approval to Use Data Compression Techniques?
    You may submit a written request to the Administrator under 
Sec. 63.1211(f) for approval to use data compression techniques to 
record data from CMS, including CEMS, on a frequency less than that 
required by Sec. 63.1209. You must submit the request for review and 
approval as part of the comprehensive performance test plan. For each 
CEMS or operating parameter for which you request to use data 
compression techniques, you must provide: (1) A fluctuation limit that 
defines the maximum permissible deviation of a new data value from a 
previously generated value without requiring you to revert to recording 
each one-minute average; and (2) a data compression limit defined as 
the closest level to an operating parameter limit or emission standard 
at which reduced recording is allowed.
    You must record one-minute average values at least every ten 
minutes. If after exceeding a fluctuation limit you remain below the 
limit for a ten-minute period, you may reinitiate your data compression 
technique provided that you are not exceeding the data compression 
limit.
    The fluctuation limit should represent a significant change in the 
parameter measured, considering the range of normal values. The data 
compression limit should reflect a level at which you are unlikely to 
exceed the specific operating parameter limit or emission standard, 
considering its averaging period, with the addition of a new one-minute 
average.
    We provide the following table of recommended fluctuation and data 
compression limits as guidance. These are the same limits that we 
discussed in the May 1997 NODA.

                               Recommended Fluctuation and Data Compression Limits
----------------------------------------------------------------------------------------------------------------
                                               Fluctuation limit ()                    Data compression limit
----------------------------------------------------------------------------------------------------------------
Continuous Emission Monitoring System:
    Carbon monoxide........................  10 ppm.......................  50 ppm.
    Hydrocarbon............................  2 ppm........................  60% of standard.
Combustion Gas Temperature Quench: Maximum   10 deg.F.....................  Operating parameter limit (OPL)
 inlet temperature for dry particulate                                       minus 30 deg.F.
 matter control device or, for lightweight
 aggregate kilns, temperature at kiln exit.
Good Combustion Practices:
    Maximum gas flowrate or kiln production  10% of OPL...................  60% of OPL.
     rate.
    Maximum hazardous waste feedrate.......  10% of OPL...................  60% of OPL.
    Maximum gas temperature for each         20 deg.F.....................  OPL plus 50 deg.F.
     combustion chamber.
Activated Carbon Injection:
    Minimum carbon injection feedrate......  5% of OPL....................  OPL plus 20%.
    Minimum carrier fluid flowrate or        20% of OPL...................  OPL plus 25%.
     nozzle pressure drop.
Activated Carbon Bed: Maximum gas            10 deg.F.....................  OPL minus 30 deg.F.
 temperature at inlet or exit of the bed.
Catalytic Oxidizer:
    Minimum flue gas temperature at          20 deg.F.....................  OPL plus 40 deg.F.
     entrance.
    Maximum flue gas temperature at          20 deg.F.....................  OPL minus 40 deg.F.
     entrance.
Dioxin Inhibitor: Minimum inhibitor          10% of OPL...................  60% of OPL.
 feedrate.
Feedrate Control:

[[Page 52962]]

 
    Maximum total metals feedrate (all       10% of OPL...................  60% of OPL.
     feedstreams).
    Maximum low volatile metals feedrate,    10% of OPL...................  60% of OPL.
     pumpable feedstreams.
    Maximum total ash feedrate (all          10% of OPL...................  60% of OPL.
     feedstreams).
    Maximum total chlorine feedrate (all     10% of OPL...................  60% of OPL.
     feedstreams).
Wet scrubber:
    Minimum pressure drop across scrubber..  0.5 inches water.............  OPL plus 2 inches water.
    Minimum liquid feed pressure...........  20% of OPL...................  OPL plus 25%.
    Minimum liquid pH......................  0.5 pH unit..................  OPL plus 1 pH unit.
    Maximum solids content in liquid.......  5% of OPL....................  OPL minus 20%.
    Minimum blowdown (liquid flowrate).....  5% of OPL....................  OPL plus 20%.
    Minimum liquid flowrate or liquid        10% of OPL...................  OPL plus 30%.
     flowrate/gas flowrate ratio.
Dry scrubber:
    Minimum sorbent feedrate...............  10% of OPL...................  OPL plus 30%.
    Minimum carrier fluid flowrate or        10% of OPL...................  OPL plus 30%.
     nozzle pressure drop.
Fabric filter: Minimum pressure drop across  1 inch water.................  OPL plus 2 inches water.
 device.
Electrostatic precipitator and ionizing wet  5% of OPL....................  OPL plus 20%.
 scrubber: Minimum power input (kVA:
 current and voltage).
----------------------------------------------------------------------------------------------------------------

    Data compression is the process by which a facility automatically 
evaluates whether a specific data point needs to be recorded. Data 
compression does not represent a change in the continuous monitoring 
requirement in the rule. One-minute averages will continue to be 
generated. With data compression, however, each one-minute average is 
automatically compared with a set of specifications (i.e., fluctuation 
limit and data compression limit) to determine whether it must be 
recorded. New data are recorded when the one-minute average value falls 
outside these specifications.
    We did not propose data compression techniques in the April 1996 
NPRM. In response to the proposed monitoring and recording 
requirements, however, commenters raise concerns about the burden of 
recording one-minute average values for the array of operating 
parameter limits that we proposed. Commenters suggest that allowing 
data compression would significantly reduce the recordkeeping burden 
while maintaining the integrity of the data for compliance monitoring. 
We note that data compression should also benefit regulatory officials 
by allowing them to focus their review on those data that are 
indicative of nonsteady-state operations and that are close to the 
operating parameter limit or, for CEMS, the emission standard.
    In response to these concerns, we presented data compression 
specifications in the May 1997 NODA. Public comments on the NODA are 
uniformly favorable. Therefore, we are including a provision in the 
final rule that allows you to request approval to use data compression 
techniques. The fluctuation and data compression limits presented above 
are offered as guidance to assist you in developing your recommended 
data compression methodology.
    We are not promulgating data compression specifications because the 
dynamics of monitored parameters are not uniform across the regulated 
universe. Thus, establishing national specifications would be 
problematic. Various data compression techniques can be successfully 
implemented for a monitored parameter to obtain compressed data that 
reflect the performance on a site-specific basis. Thus, the rule 
requires you to recommend a data compression approach that addresses 
the specifics of your operations. The fluctuation and data compression 
limits presented above are offered solely as guidance and are not 
required.
    The rule requires that you record a value at least once every ten 
minutes to ensure that a minimum, credible data base is available for 
compliance monitoring. If you operate under steady-state conditions at 
levels well below operating parameter limits and CEMS-monitored 
emission standards, data compression techniques may enable you to 
achieve a potential reduction in data recording up to 90 percent.

X. What Special Provisions Are Included in Today's Rule?

A. What Are the Alternative Standards for Cement Kilns and Lightweight 
Aggregate Kilns?
    In the May 1997 NODA, we discussed alternative standards for cement 
kilns and lightweight aggregate kilns that have metal or chlorine 
concentrations in their mineral and related process raw materials that 
might cause an exceedance of today's standard(s), even though the 
source uses MACT control. (See 62 FR 24238.) After carefully 
considering commenters input, we adopt a process that allows sources to 
petition the Administrator for alternative mercury, semivolatile metal, 
low volatile metal, or hydrochloric acid/chlorine gas standards under 
two different sets of circumstances. One reason for a source to 
consider a petition is when a kiln cannot achieve the standard, while 
using MACT control, because of raw material contributions to their 
hazardous air pollutant emissions. The second reason is limited to 
mercury, and applies when mercury is not present at detectable levels 
in the source's raw material. These alternative standards are discussed 
separately below.
1. What Are the Alternative Standards When Raw Materials Cause an 
Exceedance of an Emission Standard? See sections 1206(b) (10) and (11)
    a. What Approaches Have We Publicly Discussed? We acknowledge that 
a kiln using properly designed and operated MACT control technologies, 
including control of metals levels in hazardous waste feedstocks, may 
not be capable of achieving the emission standards (i.e., the mercury, 
semivolatile metal, low volatile metal, and/or hydrochloric acid/
chlorine gas standards). This can occur when hazardous air pollutants 
(i.e., metals and chlorine) contained in the raw material volatilize or 
are entrained in the flue gas such that their contribution to total 
metal and chlorine emissions cause an exceedance of the emission 
standard.
    Our proposal first acknowledged this possible situation. In the 
April 1996 NPRM, we proposed metal and chlorine standards that were 
based, in part, on specified levels of hazardous waste feedrate control 
as MACT control. To address our concern that kilns may not

[[Page 52963]]

be able to achieve the standards when using MACT control technologies, 
given raw material contributions to emissions, we performed an 
analysis. Our analysis estimated the total emissions of each kiln 
including emissions from raw materials, while also assuming the source 
was using MACT hazardous waste feedrate and particulate matter control. 
Results of this analysis, which were discussed in the proposal, 
indicated that there may be several kilns that would not be able to 
achieve the proposed emission standards while using MACT control, due 
to levels of metals and chlorine in raw material and/or conventional 
fuel. (See 61 FR at 17393-17406.) Commenters requested that we provide 
an equivalency determination to allow sources to comply with a control 
efficiency requirement (e.g., a minimum metal system removal 
efficiency) in lieu of the emission standard. (See response below.)
    In the May 1997 NODA, we discussed revised standards that defined 
MACT control, in part, based on hazardous waste metal and chlorine 
feedrate control--as did the NPRM. (See 62 FR 24225-24235.) However, 
our revised approach did not define specific levels of hazardous waste 
metal and chlorine feedrate control, therefore, making it difficult to 
attribute a kiln's failure to meet emission standards to metals levels 
in raw materials.254 In response to a commenter's request, 
we discussed, in the May 1997 NODA, an alternative approach to address 
raw material contributions. Our approach did not subject a source to 
the MACT standards if the source could document that metal or chlorine 
concentrations in their hazardous waste, and any nonmineral feedstock, 
is within the range of normal industry levels. The purpose of this 
requirement was to ensure that metal and chlorine emissions 
attributable to nonmineral feedstreams were roughly equivalent to those 
from sources achieving the MACT emission standards. The use of an 
industry average, or normal metal and chlorine level, was to serve as a 
surrogate MACT feedrate control level for the alternative standard 
because we did not define a specific level of control as MACT. We also 
requested comment on how best to determine normal hazardous waste metal 
and chlorine levels.
---------------------------------------------------------------------------

    \254\ We could not estimate a cement kiln's total emissions 
(i.e., to determine emission standard achievability) based on the 
assumption that the kiln is feeding metals in the hazardous waste at 
the MACT control feedrate levels.
---------------------------------------------------------------------------

    Today's final rule uses a revised standard setting methodology that 
defines specific levels of hazardous waste metal and chlorine feedrates 
as MACT control.255 As a result, we do not need to define 
normal, or average, metal and chlorine levels for the purposes of this 
alternative standard provision.
---------------------------------------------------------------------------

    \255\ As explained earlier, the emission standards for metals 
and chlorine reflect the performance of MACT control, which includes 
control of metals and chlorine in the hazardous waste feed 
materials. As further explained, sources are not required to adopt 
MACT control. Sources must, however, achieve the level of 
performance which MACT control achieves. Therefore, sources are not 
required to control metals and chlorine hazardous waste feedrates to 
the same levels as MACT control in order to comply with the 
standards for metals and chlorine. Rather, the source can elect to 
achieve the emission standard by any means, which may or may not 
involve hazardous waste feedrate control
---------------------------------------------------------------------------

    b. What Comments Did We Receive on Our Approaches? There were many 
comments supporting and many opposing the concept of allowing 
alternative standards. Several commenters focus on the Agency's legal 
basis for this type of alternative standard. Some, supporting an 
alternative standard, wrote that feedrate control of raw materials at 
mineral processing plants is not a permissible basis for MACT control. 
In support of their position, some directed our attention to the 
language found in the Conference Report to the 1990 CAA 
amendments.256 However, as we noted in the April 1996 NPRM 
and as was mentioned by many commenters 257, the Conference 
Report language is not reflected in the statute. Section 112(d)(2)(A) 
of the statute states, without caveat, that MACT standards may be based 
on ``process changes, substitution of materials or other 
modifications.''
---------------------------------------------------------------------------

    \256\ H.R. Rep. No. 101-952, at p. 339, 101st Cong., 2d Sess. 
(Oct. 26, 1990).
    \257\ See 62 FR 24239, May 2, 1997.
---------------------------------------------------------------------------

    As noted above, our MACT approach in today's rule relies on metal 
and chlorine hazardous waste feedrate control as part of 
developing MACT emission standards. It should be noted, that we do not 
directly regulate raw material metal and chlorine input under this 
approach, although there is no legal bar for us to do so. Since raw 
material feedrate control is not an industry practice, raw material 
feedrate control is not part of the MACT floor. In addition, we do not 
adopt such control as a beyond-the-floor standard. We conclude it is 
not cost-effective to require kilns to control metal and chlorine 
emissions by substituting their current raw materials with off-site raw 
materials. (See metal and chlorine emission standard discussions for 
cement kilns and lightweight aggregate kilns in Part Four, Sections VII 
and VIII.) 258
---------------------------------------------------------------------------

    \258\ The nonhazardous waste Portland Cement Kiln MACT 
rulemaking likewise controls semivolatile metal and low volatile 
metal emissions by limiting particulate matter emissions, and did 
not adopt beyond-the-floor standards based on raw material metal and 
chlorine feedrate control--see 64 FR 31898.
---------------------------------------------------------------------------

    Although today's rule offers a petition process, we considered 
varying levels of metal and chlorine emissions attributable to raw 
material in identifying the metal and chlorine emission standards 
through our MACT floor methodology. This consideration helps to ensure 
that the emission standards are achievable for sources using MACT 
control. Therefore, we anticipate very few sources, if any, will need 
to petition the Administrator for alternative standards. However, it is 
possible that raw material hazardous air pollutant levels, at a given 
kiln location, could vary over time and preclude kilns from achieving 
the emission standards. We believe, therefore, that it is appropriate 
to adopt a provision to allow kilns to petition for alternative 
standards so that future changes in raw material feedstock will not 
prevent compliance with today's emission standards.
    Other commenters believe that alternative standards are not 
necessary because there are kilns with relatively high raw material 
metal concentrations already achieving the proposed standards. To 
address this point, and to reevaluate the ability of kilns to achieve 
the emission standards without new control of metals and chlorine in 
raw material and conventional fuel, we again estimated the total metal 
and chlorine emissions, assuming each kiln fed metal and chlorine at 
the defined MACT feedrate control levels.259
---------------------------------------------------------------------------

    \259\ When estimating emissions, the Agency assumed the kiln was 
feeding metals and chlorine in its hazardous waste at the lower of 
the MACT defining maximum theoretical emission concentration levels 
or the level actually demonstrated during its performance test. See 
Final Technical Support Document for Hazardous Waste Combustor MACT 
Standards, Volume II: Selection of MACT Standards and Technologies, 
July 1999, for further discussion.
---------------------------------------------------------------------------

    The following table summarizes the estimated achievability of the 
emission standards assuming kilns used MACT control. Our analysis 
determined achievability both at the emission standard and at the 
design level--70 percent of the standard. (To ensure compliance most 
kilns will ``design'' their system to operate, at a minimum, 30 percent 
below the standard.) The table describes the number of test conditions 
in our data base that would not meet the emission standard or meet the 
design level by estimating total emissions. For example, all cement 
kiln test conditions achieve the mercury emission standard, assuming 
all cement

[[Page 52964]]

kilns used MACT control. On the other hand, the table also indicates 
that four cement kiln test conditions out of 27 do not achieve the 
design level for mercury. In our analysis, if all test conditions 
achieved both the standard and the design level, we concluded that 
there is no reason to believe raw material contributions to metal and 
chlorine emissions might cause a compliance problem.

      Cement Kiln and Lightweight Aggregate Kiln Emission Standard
                          Achievability Results
------------------------------------------------------------------------
                                                         Low
       Source category         Mercury  Semivolatile  Volatile    Total
                                            metal       metal   chlorine
------------------------------------------------------------------------
No. of cement kiln test        \1\0/27     \1\1/38     \1\1/39   \1\2/42
 conditions in MACT data base
 not achieving standard......
No of cement kiln test            4/27        6/38        3/39      3/42
 conditions in MACT data base
 not achieving 70 % design
 level.......................
No of lightweight aggregate       0/17        5/22        2/22      3/18
 kiln test conditions in MACT
 data base not achieving
 standard....................
No of lightweight aggregate       0/17        5/22        4/22     10/18
 kiln test conditions in MACT
 data base not achieving 70%
 design level................
------------------------------------------------------------------------
*Number after slash denotes total number of test conditions.

    Our analysis illustrates that, subject to the assumptions made, 
some lightweight aggregate kilns and cement kilns have raw material 
hazardous air pollutant levels that could affect their ability to 
achieve the emission standard if no additional emission controls were 
implemented (e.g., additional hazardous waste feedrate control, or 
better air pollution control device efficiency). Nevertheless, we 
conclude that it is difficult to determine whether raw material 
hazardous air pollutant contributions to the emissions result in 
unachievable emission standards because of the difficulty associated 
with differentiating raw material hazardous air pollutant emissions 
from hazardous waste pollutant emissions. This uncertainty has led us 
to further conclude that it is appropriate to allow kilns to petition 
for alternative standards, provided that they submit site-specific 
information that shows raw material hazardous air pollutant 
contributions to the emissions prevent the kiln from complying with the 
emission standard even though the kiln is using MACT control.
    Many commenters dislike the idea of an alternative standard. They 
wrote that regulation of raw material metal content may be necessary to 
control semivolatile metal and low volatile metal emissions at 
hazardous waste burning kilns because: (1) These kilns have relatively 
high chlorine levels in the flue gas (which predominately originate 
from the hazardous waste); and (2) chlorine tends to increase metal 
volatility. We agree that increased flue gas chlorine content from 
hazardous waste burning operations may result in increased metals 
volatility, which then could result in higher raw material metal 
emissions.260 The increased presence of chlorine at 
hazardous waste burning kilns presents a concern. To address this 
concern, we require kilns to submit data or information, as part of the 
alternative standard petition, documenting that increased chlorine 
levels associated with the burning of hazardous waste, as compared to 
nonhazardous waste operations, do not significantly increase metal 
emissions attributable to raw material. This requirement is explained 
in greater detail later in this section.
---------------------------------------------------------------------------

    \260\ The potential for increased metal emissions is stronger 
for semivolatile metals (lead, in particular), but low volatile 
metal emissions still have potential to increase with increased flue 
gas chlorine concentrations. See Final Technical Support Document 
for Hazardous Waste Combustor MACT Standards, Volume II: Selection 
of MACT Standards and Technologies, July 1999, for further 
discussion.
---------------------------------------------------------------------------

    Many commenters also point out that the alternative standard, at 
least as originally proposed, could result in metal and chlorine 
emissions exceeding the standard to possible levels of risk to human 
health and the environment. We agree that this potential could exist; 
however, the RCRA omnibus process serves as a safeguard against levels 
of emissions that present risk to human health or the environment. 
Therefore, sources operating pursuant to alternative standards may 
likely be required to perform a site-specific risk assessment to 
demonstrate that their emissions do not pose an unacceptable risk. The 
results of the risk assessment would then be used to develop facility-
specific metal and chlorine emission limits (if necessary), which would 
be implemented and enforced through omnibus conditions in the RCRA 
permit.261
---------------------------------------------------------------------------

    \261\ RCRA permits for hazardous waste combustors address total 
emissions, regardless of the source of the pollutant due to the 
nexus with the hazardous waste treatment activities. See Horsehead v 
Browner, 16 F. 3d 1246, 1261-63 (D.C. Cir. 1994)(Hazardous waste 
combustion standards may address hazardous constituents attributable 
to raw material inputs so long as thee is a reasonable nexus with 
the hazardous waste combustion activites).
---------------------------------------------------------------------------

    c. How Do I Demonstrate Eligibility for the Alternative Standard? 
To demonstrate eligibility, you must submit data or information which 
shows that raw material hazardous air pollutant contributions to the 
emissions prevent you from complying with the emission standard, even 
though you use MACT control for the standard from which you seek 
relief. To allow flexibility in implementation, we do not mandate what 
this demonstration must entail. However, we believe that a 
demonstration should include a performance test while using MACT 
control or better (i.e., the hazardous waste feedrate control and air 
pollution control device efficiencies that are the basis of the 
emission standard from which you seek an alternative). If you still do 
not achieve the emission standards when operating under these 
conditions, you may be eligible for the alternative standard (provided 
you further demonstrate that you meet the additional eligibility 
requirements discussed below). If you choose to conduct this 
performance test after your compliance date, you should first obtain 
approval to temporarily exceed the emission standards (for testing 
purposes only) to make this demonstration, otherwise you may be subject 
to enforcement action.
    In addition, you must make a showing of adequate system removal 
efficiency to be eligible for an alternative standard for semivolatile 
metal, low volatile metal, or hydrochloric acid/chlorine gas. This 
requirement provides a check to ensure that you are exceeding the 
emission standard solely because of raw material contributions to the 
emissions, and not because of poor system removal efficiency for the 
hazardous air pollutants for which you are seeking relief. (It is 
possible that poor system removal efficiencies for these hazardous air 
pollutants result in emissions that are higher than the emission 
standards, even though the particulate matter emission standard is 
met.) This check could be done without the expense of a second 
performance test. The system removal efficiency achieved in the 
performance test described above could be calculated for the hazardous 
air pollutants at issue. You would then

[[Page 52965]]

multiply the MACT control hazardous waste feedrate level (or the 
feedrate level you choose to comply with) 262 for the same 
hazardous air pollutant by a factor of one minus the system removal 
efficiency. This estimated emission value would then be compared to the 
emission standard, and would have to be below the standard for you to 
qualify for the alternative standard.
---------------------------------------------------------------------------

    You may choose to comply with a hazardous waste feedrate limit 
that is lower than the MACT control levels required by this 
alternative standard.
---------------------------------------------------------------------------

    As discussed in the next section, this alternative standard 
requires you to use MACT control as defined in this rulemaking. For 
lightweight aggregate kilns, MACT control for chlorine is feedrate 
control and use of an air pollution control system that achieves a 
given system removal efficiency for chlorine. Thus, lightweight 
aggregate kilns that petition the Administrator for an alternative 
chlorine standard must also demonstrate, as part of a performance test, 
that it achieves a specified minimum system removal efficiency for 
chlorine. This eligibility requirement is identical to the above-
mentioned eligibility demonstration that requires sources to make a 
showing of adequate system removal efficiency, with the exception that 
here we specify the system removal efficiency that must be 
achieved.263
---------------------------------------------------------------------------

    \263\ The requirement to achieve an 85.0% and 99.6% chlorine 
system removal efficiency for existing and new lightweight aggregate 
kilns, respectively, together with the requirement to comply with a 
hazardous waste chlorine feedrate limitation, ensures that chlorine 
emissions attributable to hazardous waste are below the standards.
---------------------------------------------------------------------------

    For an alternative mercury standard, you do not have to perform a 
performance test demonstration and evaluation. We do not require this 
test because the mandatory hazardous waste mercury feedrate specified 
in Sec. 63.1206(b)(10) and (11) ensures that your hazardous waste 
mercury contribution to the emissions will always be below the mercury 
standard.264
---------------------------------------------------------------------------

    \264\ The MACT defining hazardous waste maximum theoretical 
emission concentration for mercury is less than mercury standard 
itself, thus hazardous waste mercury contributions to the emissions 
will always be below the standard.
---------------------------------------------------------------------------

    Finally, if you apply for semivolatile metal or low volatile metal 
alternative standards, you also must demonstrate, by submitting data or 
information, that increased chlorine levels associated with the burning 
of hazardous waste, as compared to nonhazardous waste operations, do 
not significantly increase metal emissions attributable to raw 
material. We expect that you will have to conduct two different 
emission tests to make this demonstration (although the number of tests 
should be determined on a site-specific basis). The first test is to 
determine metal emission concentrations when the kiln is burning 
conventional fuel with typical chlorine levels. The second test is to 
determine metal emissions when chlorine feedrates are equivalent to 
allowable chlorine feedrates when burning hazardous waste. You should 
structure these tests so that metal feedrates for both tests are 
equivalent. You would then compare metal emission data to determine if 
increased chlorine levels significantly affects raw material metal 
emissions.
    d. What Is the Format of the Alternative Standard? The alternative 
standard requires that you use MACT control, or better, as applicable 
to the standard for which you seek the alternative. MACT control, as 
previously discussed, consists of hazardous waste feed control plus 
(for all relevant hazardous air pollutants except mercury) further 
control via air pollution control devices. Cement kilns and lightweight 
aggregate kilns will first have to comply with a specified hazardous 
waste metal and chlorine feedrate limit, as defined by the MACT 
defining maximum theoretical emission concentration level for the 
applicable hazardous air pollutant or hazardous air pollutant group. 
This work practice is necessary because there is no other reliable 
means of measuring that hazardous air pollutants in hazardous waste are 
controlled to the MACT control levels, i.e., that hazardous air 
pollutants in raw material are the sole cause of not achieving the 
emission standard. (See CAA section 112(h).) To demonstrate control of 
hazardous air pollutant metals emissions to levels reflecting the air 
pollution control device component of MACT control, you must be in 
compliance with the particulate matter standard. Finally, we require 
lightweight aggregate kilns to use an air pollution control device that 
achieves the specified MACT control total chlorine removal efficiency. 
This work practice is necessary because there is no other way to 
measure whether the failure to achieve the chlorine emission standard 
is caused by chlorine levels in raw materials.265 See 
Sec. 63.1206(b)(10) and (11) for a list of the maximum achievable 
control technology requirements for purposes of this alternative 
standard.266
---------------------------------------------------------------------------

    \265\ There is no corresponding chlorine air pollution control 
device efficiency requirement for cement kilns since air pollution 
control is not the basis for MACT control of cement kiln chlorine 
emissions.
    \266\ See also ``Final Technical Support Document for Hazardous 
Waste Combustor MACT Standards, Volume IV: Selection of MACT 
Standards and Technologies'', Chapter 11, July 1999, for further 
discussion on how the maximum achievable control technologies were 
chosen for the hazardous air pollutants.
---------------------------------------------------------------------------

    There may be site-specific circumstances which require other 
provisions, imposed by the Administrator, in addition to the mandatory 
requirement to use MACT control. These provisions could be operating 
parameter requirements such as a further hazardous waste feedrate 
limitation. For instance, a kiln that petitions the Administrator for 
an alternative semivolatile emission standard may need to limit its 
hazardous waste chlorine feedrate to better assure that chlorine 
originating from the hazardous waste does not significantly affect 
semivolatile metal emissions attributable to the raw material. As 
discussed above, a kiln must demonstrate that increased chlorine levels 
from hazardous waste do not adversely affect raw material metal 
emissions to be eligible for this alternative standard. For this 
scenario, the alternative standard would be in the form of a 
semivolatile metal hazardous waste feedrate restriction which would 
require you to use MACT control, in addition to a hazardous waste 
chlorine feedrate limit.
    Additional provisions also could include emission limitations that 
differ from those included in today's rulemaking. For example, the 
Administrator may determine it appropriate to require you to comply 
with metal or chlorine emission limitations that are than the standards 
in this final rulemaking. The emission limitation would likely consider 
the elevated levels of metal or chlorine in your raw material. This 
type of emission limitation would be no different, except for the 
numerical difference than the emission limitations in today's rule 
because it would limit total metal and chlorine emissions while at the 
same time ensuring MACT control is used. If the Administrator 
determines that such an emission limitation is appropriate, you must 
comply with both a hazardous waste feedrate restriction, which requires 
you to use MACT control, and an emission limitation. A potential method 
of determining an appropriate emission limitation would be to base the 
limit on levels demonstrated in the comprehensive performance test.
    e. What Is the Process for an Alternative Standard Petition? If you 
are seeking alternative standards because raw materials cause you to 
exceed the standards, you must submit a petition request to the 
Administrator that includes your recommended alternative

[[Page 52966]]

standard provisions. At a minimum, your petition must include data or 
information which demonstrates that you meet the eligibility 
requirements and that ensure you use MACT control, as defined in 
today's rule.
    Until the authorized regulatory agency approves the provisions of 
the alternative standard in your petition (or establishes other 
alternative standards) and until you submit a revised NOC that 
incorporates the revised standards, you may not operate under your 
alternative standards in lieu of the applicable emission standards 
found in Secs. 63.1204 and 63.1205. We recommend that you submit a 
petition well in advance of your scheduled comprehensive performance 
test, perhaps including the petition together with your comprehensive 
performance test plan. You may need to submit this petition in phases 
to ultimately receive approval to operate pursuant to the alternative 
standard provisions, similar to the review process associated with 
performance test workplans and performance test reports. After initial 
approval, alternative standard petitions should be resubmitted every 
five years for review and approval, concurrent with subsequent future 
comprehensive performance tests, and should contain all pertinent 
information discussed above.
    You may find it necessary to complete any testing associated with 
documenting your eligibility requirements prior to your comprehensive 
performance test to determine if in fact you are eligible for this 
alternative standard, or you may choose to conduct this testing at the 
same time you conduct your comprehensive performance test. This should 
be determined on a site-specific basis, and will require coordination 
with the Administrator or Administrator's designee.
2. What Special Provisions Exist for an Alternative Mercury Standard 
for Kilns?
    See Sec. 63.1206(b)(10) and (11).
    a. What Happens if Mercury Is Historically Not Present at 
Detectible Levels? Situations may exist in which a kiln cannot comply 
with the mercury standard pursuant to the provisions in Sec. 63.1207(m) 
when using MACT control and when mercury is not present in the raw 
material at detectable levels.267 As a result, today's rule 
provides a petition process for an alternative mercury standard which 
only requires compliance with a hazardous waste mercury feedrate 
limitation, provided that historically mercury not been present in the 
raw material at detectable levels.
---------------------------------------------------------------------------

    \267\ The provisions in Sec. 63.1207(m) waive the requirement 
for you to conduct a performance test, and the requirement to set 
operating limits based on performance test data, provided you 
demonstrate that uncontrolled mercury emissions are below the 
emission standard (see Part 4, Section X.B). These provisions allow 
you to assume mercury is present at half the detection limit in the 
raw material, when a feedstream analysis determines that mercury is 
not present at detectable levels, when calculating your uncontrolled 
emissions.
---------------------------------------------------------------------------

    We received comments from the lightweight aggregate kiln industry 
expressing concern with the stringency of the mercury standard. 
Commenters oppose stringent mercury standards, in part, because of the 
difficulty of complying with day-to-day mercury feedrate limits. One 
potential problem cited pertains to raw material mercury detection 
limits. Commenters point out that if a kiln assumed mercury is present 
in the raw material at the detection limit, the resulting calculated 
uncontrolled mercury emission concentration could exceed, or be a 
significant percentage of, the mercury emission standard. This may 
prevent a kiln from complying with the mercury emission standard 
pursuant to the provisions of Sec. 63.1207(m), even though MACT control 
was used.
    We agree with commenters that this is a potential problem. In 
addition, it is not appropriate to implement a mercury standard 
compliance scheme that is relatively more burdensome for kilns with no 
mercury present in raw material, as compared to kilns with high levels 
of mercury in their raw material.268 Because we establish 
provisions that provide alternatives to kilns with high levels of 
mercury in the raw material, we are doing the same for those kilns 
which do not have mercury present in raw material at detectable levels.
---------------------------------------------------------------------------

    \268\ Kilns that comply with alternative mercury standards 
because of high mercury levels in their raw material are not 
required to monitor the mercury content of their raw material unless 
the Administrator requires this as an additional alternative 
standard requirement. Thus, absent the alternative mercury standard 
discussed in this section, a source that does not have mercury 
present in their mercury at detectable levels would be subject to 
more burdensome raw material feedstream analysis requirements.
---------------------------------------------------------------------------

    b. What Are the Alternative Standard Eligibility Requirements? To 
be eligible for this alternative mercury standard, you must submit data 
or information which demonstrates that historically mercury has not 
been present in your raw material at detectable levels. You do not need 
to show that mercury has never been present at detectable levels. The 
determination of whether your data and information sufficiently 
demonstrate that mercury has not historically been present in your raw 
material at detectable levels will be made on a site-specific basis. To 
assist in this determination, you also should provide information that 
describes the analytical methods (and their associated detection 
limits) used to measure mercury in the raw material, together with 
information describing how frequently you measured raw material mercury 
content.
    If you are granted this alternative standard, you will not be 
required to monitor mercury content in your raw material for compliance 
purposes. However, after initial approval, this alternative standard 
must be reapproved every five years (see discussion below). Therefore, 
you should develop a raw material mercury sampling and analysis program 
that can be used in future alternative mercury standard petition 
requests for the purpose of demonstrating that mercury has not 
historically been present in raw material at detectable levels.
    c. What Is the Format of Alternative Mercury Standard? The 
alternative standard requires you to use MACT control for mercury 
(i.e., the level of hazardous waste feedrate control specified in 
today's rule). This alternative standard for mercury is conceptually 
identical to the emission standards in this final rule, because it 
requires the use of an equivalent level of hazardous air pollutant MACT 
control as compared to the MACT control used to determine the emission 
standards.
    The mercury feedrate control level will differ for new and existing 
sources, and will differ for cement kilns and lightweight aggregate 
kilns. See Sec. 63.1206(b) (10) and (11) for a list of the mercury 
hazardous waste feedrate control levels for purposes of this 
alternative standard.269
---------------------------------------------------------------------------

    \269\ Also see Final Technical Support Document for Hazardous 
Waste Combustor MACT Standards, Volume IV: Selection of MACT 
Standards and Technologies, Chapeter 11, July 1999, for further 
discussion on how the maximum achievable control technologies were 
chosen for mercury.
---------------------------------------------------------------------------

    d. What Is the Process for The Alternative Mercury Standard 
Petition? If you are seeking this alternative mercury standard, you 
must submit a petition request to the Administrator that includes the 
required information discussed above. You will not be allowed to 
operate under this alternative standard, in lieu of the applicable 
emission standards found in Secs. 63.1204 and 63.1205, unless and until 
the Administrator approves the provisions of this alternative standard 
and until you submit a revised NOC that incorporates this alternative 
standard.

[[Page 52967]]

We recommend that you submit these petitions well in advance of your 
scheduled comprehensive performance test, perhaps including the 
petition together with your comprehensive performance test plan. After 
initial approval, alternative standard petitions should be resubmitted 
every five years for review and approval, concurrent with subsequent 
future comprehensive performance tests, and should contain all 
pertinent information discussed above.
B. Under What Conditions Can the Performance Testing Requirements Be 
Waived? See Sec. 63.1207(m).
    In the April 1996 NPRM, we proposed a waiver of performance testing 
requirements for sources that feed low levels of mercury, semivolatile 
metal, low volatile metal, or chlorine (see 61 FR at 17447). Under the 
proposed waiver, a source would be required to assume that all mercury, 
semivolatile metal, low volatile metal, or chlorine (dependent on which 
hazardous air pollutant(s) the source wishes to petition for a waiver) 
fed to the combustion unit, for all feedstreams, is emitted from the 
stack. The source also would need to show that these uncontrolled 
emission concentrations do not exceed the associated emission 
standards, taking into consideration stack gas flow rate. The above 
requirements would apply for all periods that a source elects to 
operate under this waiver and for which the source is subject to the 
requirements of this rulemaking. All comments received on this topic 
support this approach, and no commenters suggest alternative procedures 
to implement this provision. Today's rule finalizes the proposed 
performance test waiver provision, with one minor change expected to 
provide industry with greater flexibility when demonstrating compliance 
without compromising protectiveness.
1. How Is This Waiver Implemented?
    The April 1996 proposal identified two implementation methods to 
document compliance with this waiver provision. In today's rule we 
finalize both proposed methods and add another implementation method to 
provide greater flexibility when demonstrating compliance with the 
provisions of this performance test waiver. As proposed, the first 
approach allows establishment and continuous compliance with one 
maximum total feedstream feedrate limit for mercury, semivolatile 
metal, low volatile metal, or chlorine and one minimum stack gas flow 
rate. The combined maximum feedrate and minimum stack gas flow rate 
must result in uncontrolled emissions below the applicable mercury, 
semivolatile metal, low volatile metal, or chlorine emission standards. 
Both limits would be complied with continuously; any exceedance would 
require the initiation of an automatic waste feed cut-off.
    Also as proposed, the second approach accommodates operation under 
different ranges of stack gas flow rates and/or metal and chlorine 
feedrates. Today's rule allows establishment of different modes of 
operation with corresponding minimum stack gas flow rate limits and 
maximum feedrates for metals or chlorine. If you use this approach, you 
must clearly identify in the operating record which operating mode is 
in effect at all times, and you must properly adjust your automatic 
waste feed cutoff levels accordingly.
    The third approach, which is an outgrowth of our proposed 
approaches, allows continuous calculation of uncontrolled stack gas 
emissions, assuming all metals or chlorine fed to combustion unit are 
emitted out the stack. If you use this approach, you must record these 
calculated values and comply with the mercury, semivolatile metal, low 
volatile metal, or chlorine emission standards on a continuous basis. 
This approach provides greater operational flexibility, but increases 
recordkeeping since the uncontrolled emission level must be 
continuously recorded and included in the operating record for 
compliance purposes.
    If you claim this waiver provision, you must, in your performance 
test workplan, document your intent to use this provision and explain 
which implementation approach is used. Other than those limits required 
by this provision, you will not be required to establish or comply with 
operating parameter limits associated with the metals or chlorine for 
which the waiver is claimed. Your NOC also must specify which 
implementation method is used. The NOC must incorporate the minimum 
stack gas flowrate and maximum metal and chlorine feedrate as operating 
parameter limits, or include a statement which specifies that you will 
comply with emission standard(s) by continuously recording your 
uncontrolled metal and chlorine emission rate.
    If you cannot continuously monitor stack gas flow rate, for the 
purpose of demonstrating compliance with the provisions of this waiver, 
you may use an appropriate surrogate in place of stack gas flow rate 
(e.g., cement kiln production rate). However, if you use a surrogate, 
you must provide in your performance test workplan data that clearly 
and reasonably correlates the surrogate parameter to stack gas flow 
rate.
2. How Are Detection Limits Handled Under This Provision?
    We did not address in April 1996 NPRM how nondetect metal and 
chlorine feedstream results are handled when demonstrating compliance 
with the feedrate limits or when calculating uncontrolled emission 
concentrations under this provision. Commenters likewise did not offer 
suggestions of how to handle nondetect data for this provision. After 
careful consideration, for the purposes of this waiver, we require that 
you must assume that the metals and chlorine are present at the full 
detection limit value when the analysis determines the metals and 
chlorine are not detected in the feedstream (except as described in the 
following paragraph). Because performance testing is waived under this 
provision, it is appropriate to adopt a more conservative assumption 
that metals and chlorine are present at the full detection limit for 
the purposes of this waiver. (In other portions of today's rule we make 
the assumption that 50 percent presence is appropriate given the 
different context involved). Assuming full detection limits provides an 
additional level of assurance that resulting emissions still reflect 
MACT and do not pose a threat to human health and the environment. If 
you cannot demonstrate compliance with the provisions of this waiver 
when assuming full detection limits, then you should not claim this 
waiver and should conduct emissions testing to demonstrate compliance 
with the emission standard.
    Based on the comments and as discussed in the previous section 
(Section A.2.a), we conclude it is not appropriate, for purposes of 
this performance test waiver provision, to require a kiln to assume 
mercury is present at the full detection limit in its raw material when 
the feedstream analysis determines mercury is not present at detectable 
levels. As a result, we allow kilns to assume mercury is present at 
one-half the detection limit in raw materials when demonstrating 
compliance with the performance test waiver provisions whenever the raw 
material feedstream analysis determines that mercury is not present at 
detectable levels.
C. What Other Waiver Was Proposed, But Not Adopted?
    Waiver of the Mercury, Semivolatile Metal, Low Volatile Metal, or 
Chlorine Standard

[[Page 52968]]

    We proposed not to subject sources to one or more of the mercury, 
semivolatile metal, low volatile metal, or chlorine emission standards 
(and other requirements) 270 if their feedstreams did not 
contain detectable levels of that associated metal or chlorine (e.g., 
if their feedstreams did not contain a detectable level of chlorine, 
the hydrochloric acid/chlorine gas standard would be waived--see 61 FR 
at 17447). As part of this waiver, a feedstream sampling and analysis 
plan would be developed and implemented to document that feedstreams 
did not contain detectable levels of the metals or chlorine.
---------------------------------------------------------------------------

    \270\ Ancillary performance testing, monitoring, notification, 
record keeping, and reporting requirements.
---------------------------------------------------------------------------

    Several commenters supported this waiver, stating that it is of no 
benefit to human health or the environment to require performance 
testing, monitoring, notification, and record-keeping of constituents 
not fed to the combustion unit. However, commenters were divided in 
their support of the need to set minimum feedstream detection limits. 
Those supporting specified detection limits wrote that detection limits 
are needed to ensure that appropriate analytical procedures are used 
and needed to provide consistency between sources. Those opposing 
specified detection limits believed that detection limits are highly 
dependent on feedstream matrices. Therefore, to impose a detection 
limit that applies to all sources and all feedstreams would not be 
practicable. One commenter questioned basing this waiver on nondetect 
values because a feedstream analyses that detects, at any time, a 
quantity of the metal or chlorine just above the detection limit may be 
considered to be out of compliance.
    We agree that little or no environmental benefit may be gained by 
requiring performance testing, monitoring, notification, and record 
keeping for a constituent not fed to the combustion unit. However, 
based on our careful analysis of comments and on our reevaluation of 
the practical implementation issue inherent in this type of waiver, we 
find that it may not always be practicable to use detection limits to 
determine if a waste does or does not contain metals or chlorine. We 
are concerned that facility-specific detection limits may vary, from 
source to source, at levels such that sources with detection limits in 
the high-end of the distribution (due to their complex waste matrix) 
have the potential for significant metal or chlorine emissions. Under 
the facility-specific detection limit approach, a high-end detection 
limit source with relatively high emissions could qualify for the 
waiver; however, a source with a simpler feedstream matrix with 
significantly lower amounts of metals in the feedstream (but just above 
the detection limit) would not qualify. This not only turns the 
potential benefit of a waiver provision on its head, but raises serious 
questions of national consistency, fairness, and evenness of 
environmental protection to surrounding communities. We also conclude 
that it is impractical to set one common detection limit for each 
hazardous air pollutant as part of this waiver because, as commenters 
stated, detection limits are matrix dependent.
    Due to these issues, we were unable to devise an implementable and 
acceptable nondetect waiver provision, and therefore do not adopt one 
in today's final rule. As is described in the previous section (Section 
B), however, we do provide a waiver of performance testing requirements 
to sources that feed low levels of mercury, semivolatile metal, low 
volatile metal, or chlorine. Although this waiver provision does not 
waive the emission standard, monitoring, notification, recordkeeping, 
and reporting requirements, it does waive emission tests and compliance 
with operating parameter limits for the associated metals or chlorine.
D. What Equivalency Determinations Were Considered, But Not Adopted?
    In response to comments we received from the April 1996 NPRM, we 
included in the May 1997 NODA a discussion of an allowance of a one-
time compliance demonstration for hydrocarbon and carbon monoxide at 
cement kilns equipped with temporary midkiln sampling locations. (See 
62 FR 24239.) This equivalency determination required that alternative, 
continuously monitored, operating parameters be used in lieu of 
continuous monitoring of hydrocarbon/carbon monoxide. As discussed 
below, we conclude that the shortcomings associated with the proposed 
alternative operating parameters created sufficient uncertainties, for 
implementation and overall environmental protection, that we are not 
adopting an equivalency determination option in this rulemaking. 
However, cement kilns have the opportunity to petition the 
Administrator under Sec. 63.8(f) and 63.1209(g)(1) to make a site-
specific case for this type of equivalency determination.
    In response to the April 1996 NPRM, we received comments indicating 
that some kilns would need to either operate at inefficient back-end 
temperatures (to oxidize hydrocarbons desorbed from the raw material) 
or be required to install and maintain a midkiln sampling system to 
demonstrate compliance with the hydrocarbon/carbon monoxide standards. 
Commenters believe that this may not be feasible for some kilns 
because: (1) Raising back end temperatures may increase dioxin 
formation; (2) most long kilns are not equipped to sample emissions at 
the midkiln location; (3) costs associated with retrofit and 
maintenance may be considered high; and (4) maintenance problems 
associated with the sampling duct are difficult to overcome.
    We received numerous comments on the proposed hydrocarbon/carbon 
monoxide equivalency approach described in the May 1997 NODA. Many 
cement kilns support the option and defend the use of alternative 
operating parameters in lieu of continuous carbon monoxide and 
hydrocarbon monitors. Many commenters oppose using any parameters other 
than carbon monoxide or hydrocarbon as a combustion efficiency 
indicator and as surrogate emission standards for the nondioxin organic 
hazardous air pollutants. We have found that a number of factors 
suggest that a special provision allowing use of alternative operating 
parameters, in lieu of carbon monoxide and/or hydrocarbon, is neither 
necessary nor appropriate to include in this rulemaking.
    The alternative operating parameters associated with a one-time 
demonstration would have to assure that compliance with the carbon 
monoxide/hydrocarbon standard is maintained at the midkiln location on 
a continuous basis. We considered adopting several different operating 
parameters in lieu of hydrocarbon/carbon monoxide monitoring to achieve 
this goal. Maximum production rate was considered as a continuous 
residence time indicator. Minimum combustion zone temperature, 
continuously monitored destruction and removal efficiency using sulphur 
hexafluoride, and minimum effluent NOX limits were also 
examined to ensure adequate temperature is continuously maintained in 
the combustion zone. To ensure adequate turbulence, we considered using 
minimum kiln effluent oxygen concentration. Commenters did not suggest 
additional alternative operating parameters.
    Each of these operating parameters have potential shortcomings, and 
we are not convinced that use of these parameters, even in combination, 
provides a combustion efficiency indicator as reliable as continuous

[[Page 52969]]

hydrocarbon/carbon monoxide monitoring. We have identified the 
following potential problems with these alternative operating 
parameters: (1) Effluent kiln oxygen concentration may not correlate 
well to carbon monoxide/hydrocarbon produced from oxygen deficient 
zones in the kiln; 271,272 (2) pyrometers, or other 
temperature monitoring systems, may not provide direct and reliable 
measurements of combustion zone temperature; 273 (3) some 
combustion products of sulphur hexaflouride are toxic and regulated 
hazardous air pollutants; 274 (4) there are no demonstrated 
performance specifications for continuous sulphur hexaflouride 
monitors; and (5) it is contrary to other air emission limitations (in 
principle) to require minimum (not maximum) NOX limits.
---------------------------------------------------------------------------

    \271\ An oxygen deficient zone in the kiln due to inadequate 
mixing, which could potentially result in the emission of 
significant amounts of carbon monoxide and organic hazardous air 
pollutants, could be well mixed with excess air by the time it 
reaches the kiln exit, where oxygen is monitored. Thus the oxygen 
monitor may not record any oxygen concentration change and would not 
serve as an adequate control to ensure proper combustion turbulence.
    \272\ We do not have, nor did commenters submit, data which show 
whether effluent kiln oxygen concentration adequately correlates 
with carbon monoxide/hydrocarbon produced from oxygen deficient 
zones in the kiln.
    \273\ See Part Five, Section VII.D.(2)(b)(iii), for further 
discussion on combustion zone temperature measurements.
    \274\ Hydrofluoric acid, a CAA hazardous air pollutant, is a 
possible combustion byproduct of sulphur hexafluoride.
---------------------------------------------------------------------------

    On balance, the lack of adequate documentation allowing us to 
resolve these uncertainties and potential problem areas prevents us 
from further considering this type of hydrocarbon/carbon monoxide 
equivalency determination provision for inclusion in today's final 
rule. As stated above, however, cement kilns have the opportunity to 
petition the Administrator under Sec. 63.8(f) to make a site-specific 
case for this type of equivalency determination.
    As is explained in Part Four, Section VII.C(9)(c), today's 
rulemaking subjects newly constructed hazardous waste burning cement 
kilns at greenfield sites to a main stack hydrocarbon standard of 
either 20 or 50 ppmv. We clarify that this standard applies to these 
sources even if they applied and received approval for an alternative 
monitoring approach described above, because the intent of this 
hydrocarbon standard is to control organic hazardous air pollutants 
desorbed from raw material and not to control combustion efficiency.
E. What are the Special Compliance Provisions and Performance Testing 
Requirements for Cement Kilns with In-line Raw Mills and Dual Stacks?
    Preheater/precalciner cement kilns with dual stacks and cement 
kilns with in-line raw mills require special compliance provisions and 
performance testing requirements because they are unique in design.
    Preheater/precalciner kilns with dual stacks have two separate air 
pollution control systems. As discussed in Section F below, emission 
characteristics from these separate stacks could be different. As a 
result, these kilns must conduct emission testing in both stacks to 
document compliance with the emission standards 275 and must 
establish separate operating parameter limits for each air pollution 
control device. See Sec. 63.1204(e)(1).
---------------------------------------------------------------------------

    \275\ This does not apply to the hydrocarbon and carbon monoxide 
standard. See discussion in Part Four, Section VII.D on hydrocarbon 
and carbon monoxide standards for cement kilns.
---------------------------------------------------------------------------

    Cement kilns with in-line raw mills either operate with the raw 
mill on-line or with the raw mill off-line. As discussed in Section F 
below, these two different modes of operation could have different 
emission characteristics. As a result, cement kilns with in-line raw 
mills must conduct emission testing when the raw mill is off-line and 
when the raw mill is on-line to document compliance with the emission 
standards and must establish separate operating parameters for each 
mode of operation. These kilns must document in the operating record 
each time they change from one mode of operation to the alternate mode. 
They must also begin calculating new rolling averages for operating 
parameter limits and comply with the operating parameter limits for 
that mode of operation, after they officially switch modes of 
operation. If there is a transition period associated with changing 
modes of operation, the kiln operator has the discretion to determine 
when, during this transition, the kiln has officially switched to the 
alternate mode of operation and when it must begin complying with the 
operating parameter limits for that alternate mode of operation. See 
63.1204(d)(1).
    Preheater/precalciner kilns with dual stacks that also have in-line 
raw mills do not have to conduct dioxin/furan testing in the bypass 
stack to demonstrate compliance with the standard when the raw mill is 
off-line. We have concluded that dioxin/furan emissions in the bypass 
stack are not dependent on the raw mill operating status because 
dioxin/furan emissions are primarily dependent on temperature control. 
A kiln may assume that when the raw mill is off-line, the dioxin/furan 
emissions in the bypass stack are identical to the dioxin/furan 
emissions when the raw mill is on-line and may comply with the bypass 
stack dioxin/furan raw mill on-line operating parameters for both modes 
of operation. See Sec. 63.1204(d)(1).
F. Is Emission Averaging Allowable for Cement Kilns with Dual Stacks 
and In-line Raw Mills?
    In the April 1996 NPRM, we did not subdivide cement kilns by 
process type when setting emission standards (see 61 FR at 17372-
17373). As a result, we received many comments from the cement kiln 
industry indicating that preheater/precalciner cement kilns with dual 
stacks and cement kilns with in-line raw mills have unique design and 
operating procedures that necessitate the use of emission averaging 
when demonstrating compliance with the emission standards. We addressed 
these comments in the May 1997 NODA by discussing an allowance for 
emission averaging (for all standards except for hydrocarbon/carbon 
monoxide) at preheater/precalciner cement kilns with dual stacks when 
demonstrating compliance with the emission standards (see 62 FR at 
24240). We also discussed allowing cement kilns with in-line raw mills 
to demonstrate compliance with the emission standards on a time-
weighted average basis to account for different emission 
characteristics when the raw mill is active as opposed to when it is 
inactive. In light of the favorable comments received, and the lack of 
significant concerns to the contrary, we adopt these emission averaging 
provisions in today's rule.
1. What Are the Emission Averaging Provisions for Cement Kilns with In-
line Raw Mills?
    See Sec. 63.1204(d).
    As explained in the May 1997 NODA, emissions of hazardous air 
pollutants can be different when the raw mill is active versus periods 
of time when the mill is out of service. We received many comments on 
this issue, all in favor of an emissions averaging approach to 
accommodate these different modes of operation. As a result, we adopt a 
provision that allows cement kilns that operate in-line raw mills to 
average their emissions on a time-weighted basis to show compliance 
with the metal and chlorine emission standards.
    Emission averaging for in line raw mills will not be allowed when 
they demonstrate compliance with the hydrocarbon/carbon monoxide 
standard

[[Page 52970]]

because hydrocarbon and carbon monoxide are monitored continually and 
serve as a continuous indicator of combustion efficiency. No commenter 
states that emission averaging is needed for hydrocarbon/carbon 
monoxide. Emission averaging for particulate matter will not be allowed 
because this standard is based on the New Source Performance Standards 
found in Sec. 60.60 subpart F. We interpret these standards to apply 
regardless if the raw mill is on or off. (Note that this is consistent 
with the proposed Nonhazardous Waste Portland Cement Kiln Rule. See 56 
FR 14188). In addition, emission averaging for dioxin/furan will not be 
allowed because cement kilns with in-line raw mills are expected to 
control temperature during both modes of operation to comply with the 
standard. No commenter stated that emission averaging was needed for 
dioxin/furan.
    a. What Is the Averaging Methodology? In the May 1997 NODA, we did 
not specify an averaging methodology. As a result, commenters suggested 
that the following equation would adequately calculate the time-
weighted average concentration of a regulated constituent when 
considering the length of time the in-line raw mill is on-line and off-
line:
[GRAPHIC] [TIFF OMITTED] TR30SE99.028

Where:
Ctotal = time-weighted average concentration of a regulated 
constituent considering both raw mill on time and off time.
Cmill-off = average performance test concentration of 
regulated constituent with the raw mill off-line.
Cmill-on = average performance test concentration of 
regulated constituent with the raw mill on-line.
Tmill-off = time when kiln gases are not routed through the 
raw mill.
Tmill-on = time when kiln gases are routed through the raw 
mill.

    We agree that this equation properly calculates the time-weighted 
average concentration of the regulated constituent when considering 
both raw mill operation and raw mill down time and are adopting it in 
today's rule.
    b. What Is Required During Emission Testing? As discussed, sources 
that use this emission averaging provision must conduct performance 
testing for both modes of operation (with the raw mill both on-line and 
off-line), demonstrating appropriate operating parameters during both 
test conditions. One commenter suggests that the Agency allow sources 
to demonstrate both raw mill on-line and off-line operations within the 
same test runs. This would allow a test under one condition instead of 
two and would give more flexibility by ensuring identical operating 
parameters for raw mill on-line operations as opposed to off-line 
operations. This also could theoretically result in fewer automatic 
waste feed cutoffs when transitioning from one mode of operation to 
another. Although this approach may have some benefit, we conclude that 
it is necessary to demonstrate, through separate emission testing, the 
comparison of emissions when operating with the raw mill on-line as 
opposed to the raw mill off-line. The separate emission testing is 
necessary to demonstrate whether emissions are higher or lower when the 
raw mill is not active to assure compliance with the emission standards 
on a time-weighed basis.276
---------------------------------------------------------------------------

    \276\ The Agency does not have, nor did commenters submit, 
sufficient data to determine whether emissions will be higher or 
lower when the raw mill is inactive.
---------------------------------------------------------------------------

    c. How Is Compliance Demonstrated? In the May 1997 NODA, we did not 
discuss specific compliance provisions of an emission averaging 
approach. After careful consideration, however, we determine that to 
use this emission averaging provision, you must document and 
demonstrate compliance with the emission standards on an annual basis 
by using the above equation. Shorter averaging times were considered, 
but were not chosen since it may be difficult for a kiln with an in-
line raw mill to comply with a short averaging period if the raw mill 
must be off-line for an extended period of time. Therefore, you must 
annually document in your operating record that compliance with the 
emission standard was demonstrated for the previous year's operation by 
calculating your estimated annual emissions with the above equation. 
The one-year block average begins on the day you submit your NOC. You 
must include all hazardous waste operations in that one year block 
period, and you also must include all nonhazardous waste operations 
that you elect to comply with hazardous waste MACT standards, when 
demonstrating annual compliance.277
---------------------------------------------------------------------------

    \277\ Today's rulemaking allows a hazardous waste source, when 
not burning hazardous waste, to either comply with the hazardous 
waste cement kiln MACT standards or the non hazardous waste cement 
kiln standards (see Part Five, Section I).
---------------------------------------------------------------------------

    d. What Notification Is Required? Again, in the May 1997 NODA, we 
did not discuss specific notification requirements. After careful 
consideration, we determined that if you use this emission averaging 
provision, you must notify the Administrator of your intent to do so in 
your performance test workplan. Several commenters favor allowing time-
weighted emissions averaging, so long as historical data are submitted 
to justify allowable time weighting factors (explained below). We agree 
with these comments and require that you submit historical raw mill 
operation data in your performance test workplan. These data should be 
used to estimate the future down-time the raw mill will experience. You 
must document in your performance test workplan that estimated 
emissions and estimated raw mill down-time will not result in an 
exceedance of the emission standard on an annual basis. You also must 
document in your NOC that the emission standard will not be exceeded 
based on the documented emissions from the compliance test and 
predicted raw mill down-time.
2. What Emission Averaging Is Allowed for Preheater or Preheater-
Precalciner Kilns with Dual Stacks? (See Sec. 63.1204(e).)
    As explained in the May 1997 NODA, and in an earlier 
section of this preamble (see Part Four, Section V.II.B), emissions of 
hazardous air pollutants can be different in a preheater or preheater-
precalciner cement kiln's main stack as opposed to the bypass stack. We 
received many comments on this issue, all in favor of the emissions 
averaging approach discussed in the NODA to accommodate the different 
emission characteristics in these stacks. Therefore, we today finalize 
a provision to allow preheater or preheater-precalciner cement kilns 
with dual stacks to average emissions on a flow-weighted basis to 
demonstrate compliance with chlorine and metal emission standards.
    Emission averaging to demonstrate compliance with the hydrocarbon/
carbon monoxide standard is not

[[Page 52971]]

needed at preheater and preheater-precalciner cement kilns with dual 
stacks since today's rule requires these kilns to monitor hydrocarbon 
or carbon monoxide in the bypass stack only.278 Emission 
averaging for particulate matter is no longer needed since the format 
of the standard (0.15 kg/Mg dry feed) implicitly requires the kiln to 
consider mass emissions from both stacks to demonstrate compliance with 
the emission standard. In addition, emission averaging for dioxin/furan 
will not be allowed because cement kilns with dual stacks are expected 
to control temperature in both air pollution control systems to comply 
with the standard. No commenter stated that emission averaging was 
needed for dioxin/furan.
---------------------------------------------------------------------------

    \278\ New kilns at greenfield locations must also comply with a 
main stack hydrocarbon standards. For these sources, emission 
averaging for hydrocarbons would not appropriate because the purpose 
of the main stack hydrocarbon standard is to control organic 
hazardous air pollutants that originate from the raw material.
---------------------------------------------------------------------------

    a. What Is the Average Methodology? In the May 1997 NODA, we did 
not specify an averaging methodology. However, commenters suggested 
that the following is an appropriate equation to calculate the flow-
weighted average concentration of a regulated constituent when 
considering emissions from both stacks:
[GRAPHIC] [TIFF OMITTED] TR30SE99.029

Where:
Ctot = flow-weighted average concentration of the regulated 
constituent
Cmain = average performance test concentration demonstrated 
in the main stack
Cbypass = average performance test concentration 
demonstrated in the bypass stack
Qmain = volumetric flowrate of main stack effluent gas
Qbypass = volumetric flowrate of bypass effluent gas

We agree that this equation properly calculates the flow-weighted 
average concentration of the regulated constituent when considering 
emissions from both stacks and it is adopted in today's rule.
    b. What Emissions Testing and Compliance Demonstrations Are 
Necessary? To use this emission averaging provision, you must 
simultaneously conduct performance testing in both stacks during your 
comprehensive performance test to compare emission levels of the 
regulated constituents (as proposed). These emission data must be used 
as inputs to the above equation to demonstrate compliance with the 
emission standard.
    You must develop operating parameter limits, and incorporate these 
limits into your NOC, that ensures your emission concentrations, as 
calculated with the above equation, do not exceed the emission 
standards on a twelve-hour rolling average basis. These operating 
parameters should limit the ratio of the bypass stack flowrate and 
combined bypass and main stack flowrate such that the emission standard 
is complied with on a twelve-hour rolling average basis. Whereas this 
was not proposed, we conclude that this provision is necessary to 
assure compliance with the standards since the ratio of stack gas 
flowrate and bypass stack flowrate could deviate from the levels 
demonstrated during the performance test.
    c. What Notification Is Required? In the May 1997 NODA, we did not 
discuss specific notification requirements. After careful 
consideration, however, we determine that to use this emission 
averaging provision, you must notify the Administrator of your intent 
to do so in your performance test workplan. The performance test 
workplan must include, at a minimum, information that describes your 
proposed operating limits. You must document your use of this emission 
averaging provision in your NOC and document the results of your 
emissions averaging analysis after estimating the flow weighted average 
emissions with the above equation. You must also incorporate into the 
NOC the operating limits that ensures compliance with emission 
standards on a twelve-hour rolling average basis.
G. What Are the Special Regulatory Provisions for Cement Kilns and 
Lightweight Aggregate Kilns that Feed Hazardous Waste at a Location 
Other Than the End Where Products Are Normally Discharged and Where 
Fuels Are Normally Fired? (Sec. 63.1206(b)(12) and (b)(8)(ii))
    As discussed in Part Four, Section IV.B., the Agency is allowing 
you to comply with either a carbon monoxide or hydrocarbon standard. 
However, we have concluded that this option to comply with either 
standard should not apply if you operate a cement kiln or lightweight 
aggregate kiln and feed hazardous waste at a location other than the 
end where products are normally discharged and where fuels are normally 
fired these other locations include, at the mid kiln or the cold, upper 
end of the kiln. Consistent with the Boilers and Industrial Furnace 
regulations (see Sec. 266.104(d)), we are today requiring you to comply 
with the hydrocarbon standard, and are not giving you the option to 
comply with the carbon monoxide standard, if you feed hazardous waste 
in this manner. This is because we are concerned that hazardous waste 
could be fired into a location such that nonmetal compounds in the 
waste may be merely evaporated or thermally cracked to form pyrolysis 
byproducts rather than be completely combusted.279 If this 
occurs, there is the potential that little carbon monoxide will be 
generated even though significant hydrocarbons are being emitted. 
Carbon monoxide monitoring would thus not ensure that organic hazardous 
air pollutant emissions are being properly controlled. We do not 
anticipate this requirement to be overly burdensome, since it is a 
current requirement of the Boilers and Industrial Furnace regulation.
---------------------------------------------------------------------------

    \279\ See Final Rule, Burning of Hazardous Waste in Boilers and 
Industrial Furances, February 21, 1991, 56 FR at 7158.
---------------------------------------------------------------------------

    We have also concluded that it would not be appropriate for you to 
comply with the hydrocarbon standard in the bypass duct if you operate 
a cement kiln and feed hazardous waste into a location downstream of 
your bypass sampling location relative to flue gas flow direction. Such 
operation would result in hazardous waste combustion that would not be 
monitored by a hydrocarbon monitor. Today's rulemaking thus requires 
you to comply with the main stack hydrocarbon standard of 20 ppmv if 
you feed hazardous waste in this manner. This is also consistent with 
the Boilers and Industrial Furnace regulations, which do not allow you 
to monitor hydrocarbons in the bypass duct if you operate a short kiln 
and if you feed hazardous waste in the preheater or precalciner (see 
Sec. 266.104(f)(1)).
    In addition to the above requirements, if you operate a cement kiln 
or

[[Page 52972]]

lightweight aggregate kiln and feed hazardous waste at a location other 
than the end where products are normally discharged and where fuels are 
normally fired, you are also required to demonstrate compliance with 
the destruction and removal efficiency standard every five years as 
opposed to a one-time destruction and removal demonstration We require 
you to do this because the unique design and operation of such a waste 
firing system necessitates a compliance demonstration for this standard 
every five years (see previous discussion in part Four, Section 
IV.A.3.).
H. What is the Alternative Particulate Matter Standard for 
Incinerators? See Sec. 63.1206(b)(15).
    As discussed in Part Four, Section II.A.2, today's rule establishes 
a particulate matter standard of 0.015 gr/dscf for incinerators as a 
surrogate to control nonenumerated metal hazardous air pollutants 
(i.e., antimony, cobalt, manganese, nickel, selenium). Of course, 
particulate matter air pollution control devices also exert control on 
other metals (except highly volatile species such as mercury), 
including the enumerated metals. (The enumerated metal hazardous air 
pollutants are those CAA metal hazardous air pollutants regulated 
directly via individual emission standards in today's rule, i.e., 
mercury, semivolatile metals, low volatile metals). A number of 
commenters, primarily incinerator operators, assert that a particulate 
matter standard should not be used as a surrogate control for metals in 
situations where the particulate matter does not contain any metal 
hazardous air pollutants (i.e., situations when the waste does not 
contain any metals, except perhaps mercury and the resulting ash 
contains only relatively benign ash or soot). These commenters argue 
that the cost associated with reducing particulate matter levels below 
0.015 gr/dscf would be excessive and that some type of alternative 
standard (reflecting superior metal feedrate control) be created.
    After considering these comments and another type of particulate 
matter control technology, we conclude that it is appropriate to offer 
an alternative particulate matter standard of 0.03 gr/dscf for 
incinerators that have de minimis levels of hazardous air pollutant 
metals in their feedstreams, and we have adopted a petition process to 
allow incinerators to seek this alternative standard. An alternative 
particulate matter standard is within the scope of our overall preamble 
discussions of the control of particulate matter and metal emissions, 
the ways in which the Agency was considering feedrate as part of its 
MACT analysis, our approaches to enumerated and non-enumerated CAA 
hazardous air pollutant metals, and the presentation of options for 
compliance testing when only de minimis levels of metals are present.
1. Why is this Alternative Particulate Matter Standard Appropriate 
under MACT?
    An alternative particulate matter floor level of 0.030 gr/dscf is 
appropriate for an incinerator that can demonstrate it has de minimis 
levels of CAA hazardous air pollutant metals (except mercury), as 
defined below, in its feedstreams. As discussed in other portions of 
this preamble and in our technical background documents for this 
rulemaking, control of metals (other than mercury) is a function, in a 
practical sense, of both the feedrate of those metals into the 
combustion device as well as the design, operation, and maintenance of 
a source's air pollution control devices for particulate matter. Given 
the intertwined relationship between these two factors, the Agency has 
concluded that a particulate matter floor control level of 0.015 gr/
dscf is not warranted for sources using superior feedrate control (i.e. 
beyond MACT) to reduce metal emissions, which in this case would be 
shown by having non-detectable levels of metals in their feedstreams 
(discussed in more detail below).280
---------------------------------------------------------------------------

    \280\ We do not require you to document that your feedstreams 
have de minimis mercury levels to qualify for this alternative 
standard because mercury is a volatile metal and is generally not 
controlled with particulate matter control technologies.
---------------------------------------------------------------------------

    We also conclude that the floor control for this alternative 
standard is the use of a venturi scrubber or the use of the same, but 
less sophisticated, particulate matter control technologies that were 
established for the 0.015 gr/dscf standard.281 These floor 
technologies, including venturi scrubbers, were the basis of our 
particulate matter floor standard of 0.029 gr/dscf which was published 
for comment in the May 1997 NODA. See 62 FR at 24221. Although we have 
since determined that 0.015 gr/dscf is a technically achievable and 
appropriate MACT floor control level for incinerators based on a suite 
of technologies that does not include venturi scrubbers, we conclude 
that an alternative floor level of 0.030 gr/dscf that includes venturi 
scrubbers in the floor is appropriate for sources using superior metal 
feedrate control. Put another way, we view the average of the 12 
percent best performing incinerators as including incinerators with 
venturi scrubbers when the incinerator is exercising beyond-MACT feed 
control of hazardous air pollutant metals.282 We also note 
that the final rule for medical waste incinerators establishes a 
particulate matter standard of 0.030 gr/dscf for medium sized existing 
sources and small new sources that is based on medium efficiency 
venturi scrubbers. See 62 FR at 48348. The alternative floor level of 
0.030 gr/dscf that is adopted in this final rulemaking is appropriate 
when we include venturi scrubbers as an alternative floor control 
technology when superior feed rate control is being 
employed.283
---------------------------------------------------------------------------

    \281\ As discussed in Part Four, Section VI.C.4.a, particulate 
matter floor control for hazardous waste incinerators is defined as 
the use of either fabric filters, electrostatic precipitators (dry 
or wet), or ionizing wet scrubbers (sometimes in combination with 
venturi, packed bed, or spray tower scrubbers) that achieve 
particulate matter emission levels of 0.015 gr/dscf or less.
    \282\ See Final Technical Support Document, Volume 3, Chapter 
Four, July, 1999, for further discussion.
    \283\ The cement kilns and lightweight aggregate kilns that are 
also covered by today's final rule have feedrates of metals far 
above any de minimis threshold. See Final Technical Support 
Document, Volume 3, Chapter Four, July, 1999, for further 
discussion. Therefore, in light of the commenters requesting 
alternative standards and in light of the feedstream levels of 
metals going into the kilns, we have elected to offer an alternative 
particulate matter standard only to incinerators.
---------------------------------------------------------------------------

    Particulate matter control below 0.030 gr/dscf is still necessary 
to control metal emissions at sources with de minimis levels of 
hazardous air pollutant metals in their feedstreams for several 
reasons. Even if an incinerator obtains non-detect analytical results 
for one or more metals in its feedstream, this does not conclusively 
prove that metals are absent. Rather, all that such laboratory results 
mean is that the metals are not contained in the feedstream above the 
detection limit used in the analysis. This detection limit may be low 
but it can also be fairly high depending on the waste matrix. As 
previously discussed in Part Five, Section X.C.1, commenters have 
indicated that feedstream metal detection limits are highly dependent 
on the feedstream matrix.
    Given that our prerequisite for the alternative standard is that de 
minimis levels of metals are present, we must take into account this 
phenomenon of matrix-dependent detection limits. We are unwilling 
simply to allow facilities upon a showing of non-detectable levels of 
metals to avoid particulate matter controls entirely, especially given 
the complementary controls in practice provided by both feedrate 
control and

[[Page 52973]]

particulate matter air pollution control devices. On the other hand, it 
would be overly narrow to give essentially no credit for superior 
feedrate control (shown by non-detectable levels of metals) by 
requiring these incinerators to meet 0.015 gr/dscf. It appears, 
therefore, to be an appropriate balance to allow facilities with non-
detectable levels of metals (other than mercury) to meet a standard of 
0.030 gr/dscf. This will assure control reflecting performance of the 
best performing plants that use superior (i.e., beyond MACT) feedrate 
control, especially in the event that detection limits for a particular 
waste matrix are unusually high. Because we are moving to a Performance 
Based Measurement System (PBMS) we cannot rely upon previously approved 
EPA standard methods as a means to predict detection levels in various 
matrices. Therefore, we are retaining a particulate matter standard 
0.030 gr/dscf to offset the potential for high detection limits.
2. How Do I Demonstrate Eligibility for the Alternative Standard?
    Although we adopt a particulate matter standard as a surrogate to 
control nonenumerated metal hazardous air pollutants, particulate 
matter control is an integral part of the semivolatile and low volatile 
metal emission standards as well, as discussed above. See Part Four, 
Section II.A.1, for further discussion. We therefore conclude that you 
must document that not only the nonenumerated metals meet the de 
minimis criteria explained below, but that the semivolatile and low 
volatile metals do as well. This provides assurance that superior 
feedrate control is being achieved for all hazardous air pollutant 
metals, which in turn allows us to provide you with the opportunity to 
use the alternative particulate matter standard.
    To demonstrate eligibility, you must document that you meet two 
qualification requirements. First, you must document that your 
feedstreams do not contain detectable levels of CAA hazardous air 
pollutant metals, apart from mercury (i.e., antimony, cobalt, 
manganese, nickel, selenium, lead, cadmium, chromium, arsenic and 
beryllium). This requirement is necessary to ensure that you have de 
minimis levels of metals in your feedstreams, and assures us that you 
are using superior feedrate control. You must conduct feedstream 
analyses at least annually to document that your feedstreams do not 
contain detectable levels of these metals. Permitting officials may, on 
a site-specific basis, require more frequent feedstream analyses to 
better ensure that you comply with this eligibility requirement.
    Second, you must document that your calculated uncontrolled metal 
emissions, i.e., no system removal efficiency, are below the numerical 
semivolatile and low volatile metal emission standards. When 
calculating these uncontrolled emissions, you must assume metals are 
present at one-half the detection limit and are categorized into their 
appropriate volatility grouping for purposes of this requirement. The 
one-half detection limit assumption provides a relatively, but not 
overly, conservative way assuring that de minimis determinations are 
not given to sources with very high detection limits.
    For example, the combined uncontrolled emissions for lead, cadmium 
and selenium, when assuming these metals are present at one-half the 
detection limit, must be below 240 g/dscm. The combined 
uncontrolled emissions for antimony, cobalt, manganese, nickel, 
chromium, arsenic and beryllium, when assuming these metals are present 
at one-half the detection limit, must be below 97 g/dscm. We 
require this second eligibility requirement because (1) it ensures you 
have de minimis levels of metals in your feedstreams even though metals 
can be present at levels below the detection limit, and (2) it 
encourages you to obtain reasonable detection limits.
3. What Is the Process for the Alternative Standard Petition?
    If you are seeking this alternative particulate matter standard, 
you must submit a petition request to the Administrator, or authorized 
regulatory Agency, that includes the documentation discussed above. You 
will not be allowed to operate under this alternative standard until 
the Administrator determines that you meet the above qualification 
requirements. Although we are not requiring that you include this 
petition as part of the comprehensive performance test workplan, we 
strongly recommend that you do so. This approach has several 
advantages: (1) It will clarify which PM standard you are complying 
with as of your documentation of compliance, and avoid potential 
confusion about your state of compliance; (2) it will help ensure that 
the planned performance tests cover all of the relevant parameters and 
standards and will facilitate interpretation of performance test 
results; (3) it will help avoid costs of having to conduct a separate 
performance test to show compliance with the alternative standard, 
which would include re-testing and re-establishment of many of the same 
parameters as would be covered in the initial comprehensive performance 
test; and (4) it will help maximize the time that the regulatory agency 
needs to evaluate your demonstration of the prerequisite, non-detect 
levels of metals in your feed, including the time needed for you to 
respond to any additional information that may be requested by the 
agency. Agency approval of a comprehensive performance test workplan 
that also includes this petition request will be deemed as approval for 
you to operate pursuant to this alternative standard. In our 
implementation of today's final rule, we will address as appropriate 
various considerations related to processing these petitions, including 
the timing of the submittal, review and approval. We fully expect that 
Agency permit officials will act expeditiously on these petitions so 
that both the source and the reviewing official know what particulate 
matter level the comprehensive performance test must show is being 
achieved.

XI. What Are the Permitting Requirements for Sources Subject to this 
Rule?

    As indicated in Part One, we intend the requirements of this rule 
to meet our obligations for hazardous waste combustor air emission 
standards under two environmental statutes, the Clean Air Act and the 
Resource Conservation and Recovery Act. The overlapping air emission 
requirements of these two statutes have historically resulted in some 
duplication of effort. In developing a permitting scheme that 
accommodates the requirements of both statutes, with regard to the new 
air emissions limitations and standards being promulgated in this rule, 
our goal is to avoid any such duplication to the extent possible. This 
goal is consistent with the RCRA statutory directive of section 
1006(b)(1) to ``integrate all provisions of (RCRA) for purposes of 
administration and enforcement and (* * *) avoid duplication, to the 
maximum extent practicable, with the appropriate provisions of the 
Clean Air Act.'' 284 It also is consistent with our 
objectives to streamline requirements and follow principles that 
promote ``good government.''
---------------------------------------------------------------------------

    \284\ See also CAA section 112(n)(7) (requirements of section 
112 should be consistent with those of RCRA Subtitle C to the 
maximum extent practicable).

---------------------------------------------------------------------------

[[Page 52974]]

A. What Is the Approach to Permitting in this Rule?
1. In General What Was Proposed and What Was Commenters' Reaction?
    In the April 1996 NPRM, we proposed placing the MACT air emissions 
standards in the CAA regulations at 40 CFR part 63 and proposed to 
reference the standards in the RCRA regulations at 40 CFR parts 264 and 
266. (see 61 FR 17451, April 19, 1996). At that time, we believed that 
placing the standards in both the CAA and RCRA regulations would 
provide maximum flexibility to regulatory authorities at the Regional, 
State, or local levels to coordinate permitting and enforcement 
activities in the manner most appropriate for their individual 
circumstances.285 We also believed that this approach would 
alleviate the potential for duplicative requirements across permitting 
programs.
---------------------------------------------------------------------------

    \285\ When referring to permitting under the CAA, we mean 
operating permits under title V of the CAA. The regulations 
governing state and federal title V permit programs are codified in 
40 CFR parts 70 and 71, respectively.
---------------------------------------------------------------------------

    In addition, we presented two examples of ways for permitting 
hazardous waste combustors subject to the new MACT standards. These 
examples reflected, in part, the proposed approach of incorporating the 
new MACT standards into both RCRA and CAA implementing 
regulations.286 (See 61 FR 17451, April 19, 1996.) In the 
first example, the two permitting programs would work together to issue 
one permit, under joint CAA and RCRA authority, that would meet all the 
requirements of both programs. In the second example, the two 
permitting programs would coordinate their efforts with each program 
issuing a separate permit; the items common to both (e.g., the air 
emissions standards) would be included in one permit and incorporated 
by reference into the other permit.
---------------------------------------------------------------------------

    \286\ The possibility of issuing only one EPA permit under 
either CAA or RCRA authority, and the ensuing legal barriers 
rendering that approach infeasible, also were discussed in the 
preamble for the proposed rule (61 FR 17451, April 19, 1996).
---------------------------------------------------------------------------

    Comments on the April 1996 NPRM expressed widespread support for 
providing flexibility for regulatory agencies to implement common sense 
permitting schemes that fit their organization and resources. However, 
commenters disagreed as to which approach would best provide such 
flexibility. A few commenters thought that the April 1996 NPRM 
approach, placing the standards in both CAA and RCRA regulations, would 
both provide flexibility to choose which program would issue permits 
and therefore avoid duplication.
    On the other hand, we received several comments challenging our 
assumption that placement of the standards in both CAA and RCRA 
regulations would optimize flexibility for regulatory agencies. These 
commenters believed that the regulatory agencies would be, in fact, 
more limited. They noted that both the RCRA and CAA programs would be 
responsible for incorporating the standards, to some extent, into their 
permits, even if just by referencing the other. Commenters also were 
concerned with the potential for conflicting conditions between the two 
permits, particularly with regard to testing, monitoring, and 
certification requirements. In addition, they felt that the conditions 
common to both permits might be subject to separate decision-making 
processes. For example, they might potentially be subject to two 
different administrative or judicial appeals procedures and two permit 
modification procedures. If this happened, the Agency would not achieve 
its stated objective of avoiding duplication between the two programs. 
Additionally, our example pointing to close coordination between 
programs to avoid duplication was countered by commenters examples 
where such coordination has not occurred, either due to logistical 
problems within regulatory agencies or to differences in administrative 
processes between the two programs.
    Commenters also expressed concern about the potential for 
enforcement of the same requirement under two different statutes that 
they believed the proposed approach would create. Since the 
requirements would have to be incorporated into both RCRA permits and 
CAA title V permits, sources would have to comply with both. Although 
we stated in the proposal that we did not expect to take enforcement 
action under both permits (see 62 FR 17452), commenters noted that this 
would not restrain State or local authorities from initiating dual 
enforcement actions. In addition, commenters pointed out that they 
would be vulnerable to citizen suits under both statutes.
    The majority of the commenters voiced a desire for the Agency to 
avoid duplicate requirements or redundant processes. We received 
several suggestions for alternative approaches, which can be grouped in 
three ways: (1) Requiring regulatory agencies to develop a separate 
permitting program to cover elements common to both CAA and RCRA (i.e., 
air emissions and related operating requirements) while maintaining 
separate permits for the other elements; (2) Developing a single multi-
media permit to cover all RCRA and CAA requirements applicable to 
hazardous waste combustors; and (3) placing the standards only in CAA 
regulations and incorporation only into the title V permits.
    The first alternative, i.e., requiring a separate permitting 
program for air emissions and related parameters, is a very different 
approach that would likely require the development of more new 
regulations. However, duplication may be avoided without promulgation 
of an ``independent'' permitting scheme just for the elements common to 
both RCRA and CAA programs. Other alternatives would not involve the 
time and effort needed to craft and adopt a new regulatory scheme, such 
as that suggested.
    We believe that the second alternative, pursuing multi-media 
permits, had some merit. As commenters pointed out, the Agency's 
Permits Improvement Team expressed support for multimedia permits in 
its ``Concept Paper.'' The Permits Improvement Team also acknowledged, 
however, that true multimedia permits have been difficult to develop. 
We still support multimedia permitting, and this rule does not preclude 
this approach. Nevertheless, we do not believe that, at this point, we 
can rely on multimedia permitting as an overall approach to 
implementing this rule. Some States have successfully piloted multi-
media permitting or implemented ``one-stop'' permits that address both 
RCRA and CAA requirements. We encourage States to continue these 
efforts and to apply them to hazardous waste combustor permitting to 
the extent possible. Even for States that do not currently pursue 
multimedia or one-stop permits, this rule presents unique opportunities 
to start moving in that direction.
    The third alternative had a couple of variations. The 
straightforward version was simply to place the MACT air emission 
standards in the CAA regulations, incorporate them into title V 
permits, and continue to issue RCRA permits for other RCRA-regulated 
aspects of the combustion unit, as well as of the rest of the facility 
(e.g., corrective action, general facility standards, other combustor-
specific concerns such as materials handling, risk-based emissions 
limits and operating requirements, as appropriate, and other hazardous 
waste management units). A variation of this was to develop a RCRA 
permit-by-rule provision to defer to title V permits. The 
straightforward approach was favored by the majority of the commenters. 
Some offered, as further support for this

[[Page 52975]]

position, a reference to the recommendation put forth by the Permit 
Improvement Team's Alternatives to Individual Permits Task Force that 
called for permitting air emissions from hazardous waste combustors 
under the CAA. The variation of developing a RCRA permit-by-rule 
provision is not as responsive to commenters' concerns because, among 
other things, that approach would not avoid the potential for dual 
enforcement. Although the permit-by-rule has the effect of deferring to 
the title V permit, the facility is still considered to have a RCRA 
permit for the combustor's air emissions.
2. What Permitting Approach Is Adopted in Today's Rule?
    We found the arguments for the straightforward approach (i.e., 
placing the standards only in the CAA regulations and relying on the 
title V permitting program) persuasive. Based on the comments we 
received, and our subsequent analysis, we narrowed our options for how 
to permit hazardous waste combustors subject to the new MACT standards 
and elaborated on our preferred approach in the May 1997 NODA (see 62 
FR 24249). In the NODA, we described an approach to place the MACT 
emissions standards only in the CAA regulations at 40 CFR part 63 
Subpart EEE, and rely on implementation through the air program, 
including operating permit programs developed under title V. Under this 
approach, which we are adopting in today's final rule, MACT air 
emissions and related operating requirements are to be included in 
title V permits; RCRA permits will continue to be required for all 
other aspects of the combustion unit and the facility that are governed 
by RCRA (e.g., corrective action, general facility standards, other 
combustor-specific concerns such as materials handling, risk-based 
emissions limits and operating requirements, as appropriate, and other 
hazardous waste management units).
    Placement of the emissions standards solely in part 63 appears to 
be the most feasible way to avoid duplicative permitting requirements. 
We agree with the commenters' views that placement of the standards in 
both RCRA and CAA regulations would require both permits to address air 
emissions. Permitting authorities would not be able to choose which 
program would be responsible for implementing the requirements. Placing 
the standards in both sets of regulations would obligate both programs 
to address the standards in permits issued under their respective 
authorities. Simply put, permitting authorities would not be free to 
incorporate the new standards into either CAA title V permits or RCRA 
permits; rather, they would need to incorporate the new standards, to 
some degree, into both permits.287 Having determined that 
placement of the standards in both sets of regulations is not 
desirable, we revisited the question of whether one program could defer 
to the other. The CAA does not provide authority to defer to other 
environmental statutes,288 so we could not place the MACT 
standards solely in RCRA regulations, which would have consequently 
allowed them to be incorporated only into a RCRA permit. On the other 
hand, RCRA does provide authority to forego RCRA emissions standards in 
favor of MACT standards imposed under the CAA. As stated above in Part 
One, Section I, under the authority of RCRA section 3004(a), it is 
appropriate to eliminate these RCRA standards because they would only 
be duplicative and so are no longer necessary to protect human health 
and the environment. Also as discussed there, RCRA section 1006(b) 
provides further authority for the Administrator to eliminate the 
existing RCRA air emissions standards in order to avoid duplication 
with the new MACT standards. Thus, we use our authority to defer RCRA 
controls on the air emissions to the part 63 MACT standards, which 
ultimately are incorporated into title V permits issued under the CAA.
---------------------------------------------------------------------------

    \287\ As discussed earlier, states may be able to develop 
combined permits that address both RCRA and CAA requirements. Such 
permits would have to cite the appropriate authority (CAA or RCRA) 
for each condition, and have to be signed by the appropriate 
officials of each program. Permit conditions would continue to be 
enforced under their respective authorities as well.
    \288\ Although CAA section 112(n)(7) is directed at harmonizing 
requirements with RCRA, it does not provide a jurisdictional basis 
for deferral (i.e., nonpromulgation of mandated section 112(d) MACT 
standards in light of the existence of RCRA standards).
---------------------------------------------------------------------------

    The majority of the comments received following publication of the 
May 1997 NODA supported our preferred approach to permitting the 
hazardous waste combustors. Several commenters expressed appreciation 
for this effort, and concluded that our approach would avoid 
duplication and have the RCRA and title V permits work to complement 
each other rather than potentially contradict each other. Although 
sources will still have two permits, the scope and subject matter of 
each will be distinguishable. The title V permit will focus on the 
operation of the combustion unit (e.g., air emissions and related 
parameters) while the RCRA permit will continue to focus on basic 
hazardous waste management at the facility (e.g., general facility 
standards, corrective action, other units, and so on). The only time 
there might be conditions in both RCRA and title V permits that address 
the same hazardous waste combustor operating requirements and limits is 
when there is a need to impose more stringent risk-based conditions, 
e.g., under RCRA ``omnibus'' authority, in the RCRA permit. The RCRA 
permitting authority would add terms and conditions based on the 
omnibus clause only if it found, at a specific facility, that the MACT 
standards were not sufficient to protect human health or the 
environment. This issue is discussed in greater detail in Part III, 
Section IV (RCRA Decision Process). In those limited cases, sources and 
permitting agencies may agree to identify the RCRA limit in the title V 
permit. Since one goal of the title V program is to clarify a source's 
compliance obligations, it will be beneficial, and convenient, to 
acknowledge the existence of more stringent limits or operating 
conditions derived from RCRA authority for the source in the title V 
permit, even though the requirements would not reflect CAA 
requirements. We strongly encourage Regional, State, and local 
permitting authorities to take advantage of this beneficial option.
    Some commenters continued to maintain that flexibility to choose 
which program would permit air emissions would only be provided if we 
were to promulgate the standards in both CAA and RCRA regulations. They 
reiterated the position they had taken in their comments on the initial 
proposal that this approach would not result in duplication across the 
programs; they discounted concerns over duplicative requirements or 
dual enforcement scenarios by saying that it was basically not in a 
permitting authority's best interests to issue duplicate permits. We 
found the contrary, that placement of the standards in both sets of 
regulations does not provide flexibility for a regulatory agency to 
choose one permit program or another. Such an approach would obligate 
both permits to cover air emissions and related operating requirements. 
This result does not achieve our or the commenters' objective of 
avoiding duplication across programs. Although the actual burden on 
permit writers may not be significant if, for example, the title V 
permit were to just cross-reference the appropriate sections of the 
RCRA permit, the requirements would still be enforceable under both 
vehicles, and would go through dual administrative processes. As 
mentioned above, EPA would like to

[[Page 52976]]

avoid this type of dual enforcement and dual process scenario in 
implementing the new standards.
3. What Considerations Were Made for Ease of Implementation?
    Our approach in the final rule does not limit the options available 
to state permitting authorities for implementing the new standards. The 
primary concern about which program (RCRA or CAA) assumes lead 
responsibility for administering air emissions requirements appears to 
revolve around resource issues. The RCRA program has been the lead 
program for permitting hazardous waste combustors for many years, 
consequently, RCRA program staff have developed a great deal of 
expertise in this area. They are familiar with source owners and 
operators, the combustion units, and special considerations associated 
with permitting hazardous waste combustion activities. Some commenters 
are concerned that by deferring regulation of air emissions standards 
to the CAA, that expertise will no longer be available. They express 
doubt about the ability of air toxics implementation programs and title 
V programs to take on these sources, given the complexity of hazardous 
waste combustor operations and the volume of title V permits that need 
to be issued over the next several years.289
---------------------------------------------------------------------------

    \289\ Title V permits are required for many more sources than 
those subject to the HWC MACT standards. Currently, there are 
approximately 20,000 sources that are subject to title V; there are 
only about HWCs subject to today's rule.
---------------------------------------------------------------------------

    In response to these comments, we note that many State Air programs 
currently play key roles in permitting hazardous waste combustors under 
RCRA. Furthermore, States may find that much of the expertise used to 
regulate other air sources is directly applicable to regulating the 
hazardous waste combustor sources subject to the new MACT standards, 
and that the resources in their air programs are sufficient to handle 
these additional sources. If, however, a State shares commenters' 
concerns that its air program, as it currently exists, may not be able 
to take on these sources, the State may continue using the resources 
and expertise of its RCRA program even though the new standards are 
being promulgated as part of the CAA regulations.
    In the May 1997 NODA, we discussed the flexibility afforded to 
States by codifying the standards under only one statute (see 62 FR 
24246). Two potential options were described in the NODA for how this 
might be achieved: (1) A State could simply have its RCRA staff 
implement the hazardous waste combustor MACT standards; or (2) a State 
could formally incorporate the standards into its State RCRA program. 
In response to the NODA, some State environmental agencies commented 
that, as a matter of State law, they would not be able to incorporate 
the new standards into their authorized hazardous waste programs unless 
they are included in federal RCRA regulations. We acknowledge, 
therefore, that some States may not be able to pursue the second 
option. In any case, we recommend against this option because, as 
discussed below, it would perpetuate having duplication between two 
permits. The first option would, however, still be feasible. For 
example, the States could explore the flexibility provided through 
Performance Partnership Agreements 290 if they would like to 
have their RCRA program staff continue their work with the hazardous 
waste combustors.
---------------------------------------------------------------------------

    \290\ Within negotiated agreements, there is flexibility in 
Performance Partnership Grants to strategically move funds, and 
flexibility in Performance Partnership Agreements found in the 
National Environmental Performance Partnership System to 
strategically integrate programs.
---------------------------------------------------------------------------

    If a State chooses to use either of the above options to continue 
applying RCRA expertise to hazardous waste combustors, we anticipate 
that RCRA program staff would be responsible for many of the 
implementation activities, such as reviewing documents submitted by the 
source (e.g., the Notice of Intent to Comply, the progress report, and 
the performance test plan), and working with the source to resolve any 
differences (e.g., on anticipated operating requirements or on results 
of comprehensive performance tests).
    Where the process issues would start to diverge between the two 
options is at the actual permitting stage. Under the first option (RCRA 
staff implementing CAA regulations), the standards would be 
incorporated only into title V permits. Title V permits cover a wide 
range of applicable requirements under the CAA; the hazardous waste 
combustor MACT standards are likely to be just one piece.291 
We believe that the RCRA permit writer would draft the hazardous waste 
combustor portion of the title V permit, and would coordinate with the 
title V permit writer in the CAA program who has responsibility for the 
source's overall permit to ensure that the hazardous waste combustor 
portion is properly incorporated. In short, the RCRA permit writer 
would simply be developing a component of a title V permit instead of 
developing a component of a RCRA permit. State permitting authorities 
that wish to continue using their RCRA expertise will undoubtedly 
explore this approach.
---------------------------------------------------------------------------

    \291\ If the HWC MACT standards are the only applicable CAA 
requirements, however, then there would be no other components of a 
title V permit for the source.
---------------------------------------------------------------------------

    If a State pursues the second option of incorporating the new 
hazardous waste combustor MACT standards into its State RCRA program, 
there may still be a need to incorporate the standards into both title 
V and RCRA permits. The CAA does not provide authority to defer title V 
permitting to other environmental programs. Thus, the source would 
still be subject to title V requirements (i.e., a RCRA permit could not 
``replace'' a title V permit). Furthermore, an EPA Region or a State 
who chooses to obtain authorization for the hazardous waste combustor 
MACT standards under RCRA would also have to start implementing the new 
standards under CAA authority (including title V permitting 
requirements) even as the State begins efforts to incorporate the 
standards into its State RCRA program.
    Although close cooperation between the RCRA and title V permit 
writers could minimize duplicative efforts in developing permits and 
avoid conflicting conditions in the two permits (for example, by 
putting the conditions in one permit and just referencing them in the 
other), this approach still results in the potential for enforcement 
and citizen suits under both permits. 292 As discussed 
above, we intend to avoid duplicate permitting and enforcement 
scenarios for hazardous waste combustor MACT standards; thus, we 
strongly encourage States that choose to pursue this approach to 
develop implementation schemes that minimize the potential for such 
duplication to the extent practicable.
---------------------------------------------------------------------------

    \292\ Some States have successfully issued ``one-stop'' 
multimedia permits which include provisions from both the CAA and 
RCRA programs in a single permit. However, it is EPA's understanding 
that these permits cite both the RCRA and CAA authority; thus, the 
potential for enforcement under both statutes still remains.
---------------------------------------------------------------------------

B. What Is the Applicability of the Title V and RCRA Permitting 
Requirements?
    This section briefly summarizes the applicability of both title V 
and RCRA permitting requirements under the permitting scheme discussed 
in Section XI. A. above. It also discusses the relationship of this 
permitting scheme to both the proposed revisions to combustion 
permitting procedures from June 1994 and to the RCRA preapplication 
meeting requirements. Our decision to subject hazardous waste 
combustors that are considered area

[[Page 52977]]

sources under the CAA to title V permitting is discussed in a separate 
section.
1. How Are the Title V Permitting Requirements Applicable?
    We intend, by placing the new standards only in 40 CFR part 63 and 
not cross-referencing them in RCRA regulations, to rely on existing air 
programs to implement the new requirements, including operating permits 
programs developed under title V. All hazardous waste combustors 
subject to the MACT standards promulgated in this rule will thus be 
subject to title V permitting requirements for air emissions and 
related operating requirements (this includes hazardous waste 
combustors that are considered area sources under the CAA, as discussed 
in more detail below). In this rule, we are not amending any of the 
existing air permitting procedures. The procedures of 40 CFR part 71 
for federal operating permits, or a State title V program approved 
under part 70, will remain applicable. Thus, all current CAA 
requirements governing permit applications, permit content, permit 
issuance, renewal, reopenings and revisions will apply to air emissions 
from hazardous waste combustors pursuant to promulgation of the 
hazardous waste combustor MACT standards.293
---------------------------------------------------------------------------

    \293\ Requirements of other CAA permitting programs, such as 
construction permits, will continue to apply, as appropriate, to the 
HWC's sources subject to today's rule.
---------------------------------------------------------------------------

    The public participation requirements for title V permits in parts 
70 and 71, such as allowing an opportunity for public hearing and 
public comments on draft permits, also apply (see 40 CFR 70.7(h) and 
71.11). We are committed to enhancing public participation in all of 
our programs. In 1996, we published a guidance manual on public 
involvement in the RCRA program intended to improve cooperation and 
communication among all participants in the RCRA permitting process 
(RCRA Public Participation Manual, EPA530-R-96-007, September 1996). 
Although the Manual is written in the context of the RCRA program, the 
principles are common to all program areas. For example, the Manual 
encourages early and meaningful involvement for communities and open 
access to information. It also acknowledges the important role of 
public participation in addressing environmental justice concerns. 
Since these principles are applicable in all situations, we encourage 
air programs and sources subject to the hazardous waste combustor MACT 
standards to refer to the RCRA manual for additional guidance on 
implementing effective public participation activities.
2. What Is the Relationship Between the Notification of Compliance and 
the Title V Permit?
    The hazardous waste combustor MACT standards promulgated in this 
final rule include emissions limitations for several hazardous air 
pollutants, as well as detailed compliance, testing, monitoring, and 
notification requirements. Under these provisions, you not only 
demonstrate compliance with the emissions limitations, but also 
demonstrate that you have established operating requirements and 
monitoring methods that ensure continuous compliance with those limits. 
These demonstrations are made during a comprehensive performance test 
and subsequently documented in an NOC.
    We are requiring, in Sec. 63.1210(f), that you comply with the 
general provisions governing the NOC codified in Sec. 63.9(h). Those 
provisions specify that in addition to describing the air pollution 
control equipment (or method) for each emission point for each 
hazardous air pollutant, the NOC also must include information such as: 
methods that were used to demonstrate compliance; performance test 
results; and methods for determining continuous compliance (including 
descriptions of monitoring and reporting requirements and test 
methods). We also are requiring in Sec. 63.1207(j) that you comply with 
the all of the operating requirements specified in the NOC upon 
submittal to the Administrator.
    Although these requirements are self-implementing, in that you must 
comply in accordance with the time frames set forth in today's rule, 
the requirements are ultimately implemented through title V operating 
permits (see 40 CFR parts 70 and 71). Section 63.1206(c)(1) specifies 
that: (1) You can only operate under the operating requirements 
specified in the DOC or NOC (with some exceptions as laid out in the 
regulations); (2) the DOC and NOC must contain operating requirements 
including, but not limited to, those in Sec. 63.1206 (compliance with 
the standards and general requirements) and Sec. 63.1209 (monitoring 
requirements); (3) operating requirements in the NOC are applicable 
requirements for the purposes of 40 CFR parts 70 and 71; and, (4) 
operating requirements in the NOC must be incorporated into the title V 
permit. In addition, because title V permits can only be issued if, 
among other conditions, ``the conditions of the permit provide for 
compliance with all applicable requirements'' (see Secs. 70.7(a)(1)(iv) 
and 71.7(a)(1(iv)), parts 70 and 71 are clear that title V permits must 
contain the operating requirements documented in the NOC.
    As mentioned above, you must comply with all operating requirements 
specified in the NOC as of the postmark date when the NOC is submitted 
to the Administrator. Operating requirements documented in the NOC must 
be included in your title V permit--either through initial issuance if 
you do not yet have a title V permit, or through a permit revision if 
you already have a permit. Including information from the initial NOC 
in title V permits should not create the potential for any compliance 
conflicts. Because it is the first time the NOC operating requirements 
are incorporated into the permit, there would be no requirements 
already on permit with which the NOC would conflict.
    However, the potential for compliance conflicts could be created 
when a subsequent NOC is submitted. For example, you are required to 
conduct periodic comprehensive performance testing (see 
Sec. 63.1207(d)(1)). Subsequent to each test, you must submit another 
NOC to the Administrator. Because of the dynamics of the testing and 
permitting cycles, it is possible that once you have information from 
the initial NOC in the permit, you could find yourself, after 
subsequent testing, in a situation where there might be potentially 
conflicting requirements with which you must comply (i.e., requirements 
in the title V permit and requirements in the most recently submitted 
NOC). This might occur, for example, if any of the operating 
requirements changed from the previous test.294 The 
potential for compliance conflicts that might arise from this situation 
can be avoided, however, by following the guidance presented below.
---------------------------------------------------------------------------

    \294\ On the other hand, if the limits did not change, there 
would be no conflict between the NOC and the permit.
---------------------------------------------------------------------------

    The requirements in parts 70 and 71 govern the timing and 
procedures for permit issuance, revisions, and renewals, and you should 
refer to those requirements when obtaining or maintaining your permit. 
For today's rule, we provide guidance on what we recommend as to how 
operating requirements in the NOC should be incorporated into title V 
permits.295
---------------------------------------------------------------------------

    \295\ We are recommending this approach as guidance in the 
preamble, but not including any associated regulatory provisions. 
This guidance is essentially an interpretation of the current part 
70 and 71 rules.

---------------------------------------------------------------------------

[[Page 52978]]

    For incorporating information from an initial NOC into a title V 
permit, when you have an existing title V permit, we recommend that you 
and your permitting agency follow the procedures for significant 
modifications. The primary rationale for using these procedures is to 
afford the public an opportunity to review all of the information 
pertinent to your compliance obligations. We want to ensure a level of 
public involvement when including operating requirements in title V 
permits that is commensurate with that under RCRA. In RCRA, operating 
parameters are initially developed pursuant to trial burns and 
incorporated into permits either through initial issuance (in the case 
of facilities operating under RCRA interim status) or through a RCRA 
class 2 or 3 permit modification (in the case of new facilities). In 
either situation, significant opportunities exist for public review and 
input parallel to those under initial title V permit issuance or 
significant permit modification procedures.
    With regard to a subsequent NOC developed pursuant to periodic 
performance tests, we prefer an implementation scheme for this rule 
that avoids unnecessary permit revisions. Thus, we recommend that you 
coordinate your five-year comprehensive performance testing schedule 
with your five-year permit term to the extent possible. This would 
allow changes in the NOC to be incorporated into the permit at renewal 
rather than through separate permit revisions. This also helps to 
minimize the number of permit revisions, as well as, the likelihood of 
having two sets of requirements with which to comply.
    We recognize, however, that such coordination may not always be 
possible or feasible. At times, it may be necessary to include 
information from the most recent NOC through a permit revision. We 
expect that this will be accomplished using, at most, the minor permit 
modification procedures in Sec. 70.7(e)(2) or Sec. 71.7(e)(1). Keeping 
in mind that the information from the initial NOC was included either 
as part of the initial permit issuance or as a significant revision, 
the information was already subject to review by both the regulatory 
agency and the public. Thus, the public should have a clear 
understanding of your compliance obligations. The obligation to comply 
with the emissions limitations in Secs. 63.1203, 63.1204, or 
Sec. 63.1205 does not change even if any of the associated compliance 
information, such as operating limits, is revised pursuant to 
subsequent performance tests. Given our experience in regulating (under 
RCRA) the types of sources subject to today's MACT standards, we do not 
expect the information in a NOC to change significantly over time. We 
have been regulating these sources for almost twenty years; the testing 
and monitoring requirements we are promulgating in this rule reflect 
the ``lessons learned'' over time. Thus, the initial set of compliance 
parameters are likely to need primarily minor changes over time. You 
and your regulatory agency also are experienced in setting operating 
parameter limits and monitoring systems to ensure compliance with 
performance standards. Again, this expertise and experience suggests 
that primarily minor adjustments will need to be made. In light these 
factors, we are confident that changes in the NOC may be appropriately 
incorporated into title V permits using the minor permit revisions 
procedures. Furthermore, regulatory agencies are obligated under 
Sec. 63.1206(b)(3) to make a finding of compliance based on performance 
test results. This requirement provides an additional administrative 
safeguard to ensure that you are setting the proper operating limits.
    The minor permit modification process will allow you to meet your 
compliance obligations under Sec. 63.1207(j) and begin to comply with 
the conditions in the NOC upon submittal (i.e., post-mark). Under 
Secs. 70.7(e)(2)(v) and 71.7(e)(1)(v), you may make the change proposed 
in the minor permit modification application immediately after filing 
such application. Following this, you must comply with both the 
applicable requirements governing the change and the proposed permit 
terms and conditions (i.e., the information from the NOC that you are 
incorporating into your permit). The provisions in this section also 
ensure that you will not be in the position of having to choose between 
compliance with the NOC or compliance with your permit because this 
section also specifies that during this time period, you need not 
comply with the existing permit terms and conditions you seek to 
modify.296 Since the NOC is submitted to the Administrator 
once you have a title V permit (see Sec. 63.9(h)(3)), we expect that 
you will submit the NOC together with a minor permit modification 
application. Any modifications added to the permit through this process 
can be reviewed by the public at the time of permit renewal.
---------------------------------------------------------------------------

    \296\ If, however, the source fails to comply with its proposed 
permit terms and conditions during this time period, the existing 
terms and conditions it seeks to modify may be enforced against it 
(Secs. 70.7(e)(2)(v) and 71.7(e)(1)(v)).
---------------------------------------------------------------------------

    We encourage permitting authorities to develop permits in a way 
that minimizes the need for future permit revisions and is consistent 
with the requirements in parts 70 and 71. For example, you may request 
that your permitting authority develop a permit that contains 
alternative operating scenarios. This would allow you to alternate 
among various approved operating scenarios while concurrently noting 
the change in your operating record.
3. Which RCRA Permitting Requirements Are Applicable?
    The RCRA permitting requirements particular to incinerators and 
boilers and industrial furnaces are found in 40 CFR 270.19, 270.22, 
270.62, and 270.66. These permitting requirements apply to new 
facilities, to those operating under interim status while they pursue a 
permit, and to sources seeking to renew their permits. In today's final 
rule, we amend the introductory text in each of these sections to 
reflect that RCRA permitting requirements for hazardous waste combustor 
air emissions and related operating parameters will not apply once you 
demonstrate compliance with the requirements of the new MACT standards 
by completing a comprehensive performance test and submitting a NOC to 
the Administrator.297 The timing for the deferral of the 
RCRA permitting requirements is consistent with the timing in today's 
rule for the deferral of applicable standards in 40 CFR parts 264 and 
265.
---------------------------------------------------------------------------

    \297\ The final rule language in these sections differs from 
that in the NPRM to reflect placement of the standards only in part 
63 and deferral of RCRA controls to the air program.
---------------------------------------------------------------------------

    Even though we rely on the title V permitting program to address 
air emissions from hazardous waste combustors, we still need RCRA 
permits at these sources to address: (1) Other RCRA regulations 
applicable to all types of RCRA units, including hazardous waste 
combustors, that are not duplicated under the CAA; (2) any risk-based 
emissions limits and operating parameters, as appropriate; and (3) 
other RCRA units at the facility. Also, new facilities (including new 
hazardous waste combustor units) must obtain RCRA permits prior to 
starting construction. Thus, the remaining RCRA permitting requirements 
in 40 CFR part 270 governing permit applications and permit content 
continue to apply. These

[[Page 52979]]

include the provisions in Secs. 270.10(k) and 270.32(b)(2), which 
together provide authority to require a facility owner or operator to 
submit information necessary to establish permit conditions and to 
impose site-specific conditions, including risk-based conditions, 
through the RCRA permit.
    Even though you will still have two permits, the scope and subject 
matter of each are distinguishable. The title V permit will focus on 
the operation of the combustion unit (e.g., air emissions and related 
parameters) while the RCRA permit will continue to focus on the other 
basic aspects of hazardous waste management. The RCRA permit would thus 
include conditions to ensure compliance with relevant requirements in 
40 CFR part 264, including: General facility standards; preparedness 
and prevention; contingency planning and emergency procedures; 
manifesting; recordkeeping and reporting; releases from solid waste 
management units; closure; post-closure; financial responsibility; 
corrective action; storage; materials handling; and air emissions 
standards for process vents and equipment leaks from tanks and 
containers.
    The only time we foresee that conditions in both RCRA and title V 
permits may govern the same hazardous waste combustor operating 
parameters and limits is when there is a need to impose more stringent 
or more extensive risk-based conditions, e.g., under RCRA omnibus 
authority, to ensure protection of public health and the environment. 
This situation is discussed in greater detail in Part Three, Section IV 
(RCRA Site Specific Risk Assessment Decision Process).
4. What Is the Relationship of Permit Revisions to RCRA Combustion 
Permitting Procedures?
    In June, 1994, we published a proposed rule for RCRA Expanded 
Public Participation and Revisions to Combustion Permitting Procedures 
(59 FR 28680, June 2, 1994). The proposal contained amended procedures 
for interim status combustion facilities during the trial burn period 
that were intended to make the procedures for interim status facilities 
more like those governing permitted facilities. We finalized the 
expanded public participation requirements (see section immediately 
below), but did not finalize the proposed permitting revisions. At the 
time we began to finalize the proposal, we were already committed to 
issuing comprehensive air emissions standards under MACT. It was 
anticipated that there would be overlap between the emissions standards 
in the proposed MACT rule and the combustion permitting procedures in 
the June 1994 proposed rule. It did not make sense to finalize 
provisions in one rulemaking effort only to propose changing them yet 
again in another rulemaking effort. Now, given the approach being 
adopted in today's final rule to permit hazardous waste combustor air 
emissions under title V of the CAA, there is no longer as strong a need 
to pursue the amended procedures for RCRA permitting in the June 1994 
proposal. We do not, therefore, intend at this time to finalize these 
proposed permitting amendments.
5. What Is the Relationship to the RCRA Preapplication Meeting 
Requirements?
    In 1995, we finalized the expanded RCRA public participation 
requirements (60 FR 63417, December 11, 1995). These included 
requirements for a facility to advertise and conduct an informal 
meeting with the neighboring community to discuss anticipated 
operations prior to submitting a RCRA Part B permit application. Since 
hazardous waste combustors subject to the new MACT standards (and title 
V permitting) still need RCRA permits for other hazardous waste 
management activities, you are still subject to the RCRA preapplication 
meeting requirements in 40 CFR 124.31. Even though operations and 
emissions associated with the combustor unit are now to be addressed 
primarily under CAA requirements, we anticipate that the public will 
continue to exhibit a great deal of interest in combustor activities at 
RCRA meetings. They may not always be familiar with our administrative 
``boundaries'' dictated by the various environmental statutes. Given 
this potential lack of familiarity, and because combustor units and 
emissions are already discussed at these meetings, we strongly 
encourage you to continue including combustor unit operations in 
discussions during RCRA preapplication meetings. Furthermore, 
conditions for hazardous waste combustor activities may sometimes be 
imposed under RCRA, for example, in cases where the results of a site-
specific risk assessment indicate a need for conditions more stringent 
or more extensive than those imposed under MACT. You should be prepared 
to discuss the site-specific risk assessment process and how it may 
result in additional conditions being included to their RCRA permits.
    All other public participation requirements in 40 CFR part 124 
associated with the RCRA permitting process continue to apply. These 
include requirements for public notice at application submittal, public 
notice of the draft permit, opportunity for public comments on the 
draft permit, and opportunity for public hearings. These requirements 
also are explained in the RCRA Public Participation Manual (EPA530-R-
96-007, September 1996), which provides guidance on how to implement 
RCRA public participation requirements, as well as, recommendations on 
how to tailor public involvement activities to the situation at hand. 
For example, if the community around a facility does not speak English 
as a primary language, the manual encourages use of multilingual fact 
sheets. As mentioned previously, we encourage you and States to apply 
the principles contained in the RCRA manual to hazardous waste 
combustor MACT compliance and title V activities as well.
C. Is Title V Permitting Applicable to Area Sources?
    Under today's rule, hazardous waste combustors meeting the 
definition of an area source will be subject to today's MACT standards 
(see discussion in Part One, Section III.B). As discussed in the May 
1997 NODA, under Sec. 63.1(c)(2), area sources subject to MACT are 
subject to title V permitting as well, unless the standards for that 
source category (e.g., subpart EEE for hazardous waste combustors) 
specify that: (1) States will have the option to exclude area sources 
from title V permit requirements; or (2) States will have the option to 
defer permitting of area sources. We received several comments on our 
NODA discussion (see 62 FR 24215) on the issue of subjecting area 
sources to title V permitting. The comments were fairly evenly split--
several supported requiring area sources to obtain title V permits, 
while several were against it. After considering the comments, we have 
chosen not to provide the option to the States to exclude hazardous 
waste combustor area sources from title V permitting requirements or to 
defer permitting of these sources.
    Commenters that support the Agency's position affirm that title V 
permits serve an important role to incorporate all requirements 
applicable to a source in one enforceable permitting document. They 
maintain that the compliance certifications and opportunities for 
public involvement inherent in the title V program will serve a useful 
and valuable public service. Other supporters note that requiring all 
hazardous waste combustors to obtain title V permits will help to 
ensure that the permits are both consistent and adequate. The idea of

[[Page 52980]]

consistency being a desirable end result is echoed by others as well. 
One commenter points out that area sources in several other source 
categories are not exempt from title V permitting requirements, and 
recommends that hazardous waste combustor area sources also be subject 
to title V to maintain consistency with the rest of the MACT program. 
Finally, some commenters state that if the Agency were not to pursue 
title V permitting for hazardous waste combustor area sources, then the 
Agency would have to strengthen the nontitle V permitting programs with 
respect to public involvement and agency approval of modifications 
relating to facility emissions.
    We agree with these points. Title V permits clarify your regulatory 
obligation, thereby making it easier for you to keep track of your many 
compliance obligations across several air programs. Clarifying the 
regulatory obligations improves compliance in many cases; we have seen 
an increase in compliance among air sources with the advent of the 
title V permitting program. For example, through the process of 
applying for and issuing title V permits, applicable requirements of 
which a source is unaware or with which it is found to be out of 
compliance are identified. Once these requirements are included in a 
title V permit, the source must certify compliance with these 
requirements both initially and then on an annual basis.
    We concur with commenters about the benefits of the public 
involvement opportunities afforded by the title V permit program. Our 
experience in the RCRA combustion program has shown that many of the 
sources that would fall into the area source classification (e.g., some 
commercial incinerators and cement kilns burning hazardous waste as 
fuel) are the ones in which the public is generally most interested. 
Subjecting hazardous waste combustor area sources to title V permitting 
will ensure that the public will continue to be involved in permit 
decisions under the CAA, as they have been under RCRA. For example, the 
public will have an opportunity to comment on and request a public 
hearing for a draft title V permit. They have access to State or 
Federal court to challenge title V permits, depending upon whether the 
permit is a part 70 or part 71 permit. Title V also provides greater 
access to information about sources in many cases. Under title V, 
States and EPA cannot deny basic information about sources to citizens 
unless it is protected as confidential business information. 
Conversely, there could be disparity in what information citizens might 
be able to obtain under State non-title V operating permits.
    Consistency is a key objective as well. Part 70 sets out the 
minimum criteria that a State program must meet. If a State fails to 
develop and implement a program that meets these minimum criteria, then 
a part 71 federal operating permits program is put into place. These 
minimum criteria provide for consistency across State and Federal title 
V permitting programs, which might not occur under other State air 
permitting programs. Consistency within CAA programs is not the only 
concern. We also are, as part of our approach to integrating regulation 
of these sources under RCRA and the CAA, striving to maintain 
consistency with how sources have been regulated under RCRA. Under 
RCRA, all of the sources that would fall into an area source 
classification are currently treated the same as the sources that are 
classified as major under the CAA. It is appropriate to continue 
treating all hazardous waste combustor sources in the same manner 
(i.e., to apply the same permitting requirements to all of these 
sources) under the CAA.
    Commenters that do not support applying title V requirements to 
area sources generally base their position on three arguments. First, 
they argue that Congress had consciously differentiated between area 
and major sources when developing the CAA, so that there would be a 
strong incentive for facilities to limit emissions and thus avoid the 
additional requirements imposed on major sources. These commenters 
maintain that subjecting area sources to title V requirements would 
create a disincentive for these sources to minimize emissions. 
Secondly, they suggest that other CAA permitting mechanisms, such as 
federally enforceable state operating permits, might be more 
appropriate for the hazardous waste combustor area sources. One 
commenter notes that some sources have already invested a lot of time 
and effort working with permitting authorities to develop federally 
enforceable state operating permits that limit their potential to emit 
below major source levels, and that the Agency's action subjecting 
these sources to title V permits would render this work meaningless. 
Finally, they assert that this would be the first time the Agency did 
not provide the option to the States to either defer title V permitting 
for area sources or exempt them entirely, and they express concern 
about the precedent that would be set if the Agency were to start 
requiring area sources to obtain title V permits in this rule.
    After careful consideration, we are not persuaded by these counter-
arguments. Although the CAA does differentiate in some provisions 
between area and major sources, it did not specify that area sources 
should be exempt from the title V permitting program. On the contrary, 
it provides discretionary authority in section 502(a) for the 
Administrator to decide whether to exempt a source category, in whole 
or in part, from title V permitting requirements. Furthermore, the 
implementing regulations in 40 CFR 70.3(b)(2), 71.3(b)(2), and 
63.1(c)(2) specify that the Administrator will determine whether to 
exempt any or all area sources from the requirement to obtain a title V 
permit at the time new MACT standards are promulgated. Clearly, the 
decision to subject area sources to title V permitting is intended to 
be made in the context of both the source category and the applicable 
standards. The exemption from title V may only be provided if 
compliance with the requirements would be ``impracticable, infeasible, 
or unnecessarily burdensome.'' CAA section 502(a). Given that the 
hazardous waste combustors subject to today's rule, including those 
that may meet the definition of area sources, have all been subject to 
common permitting regulations under RCRA, subjecting these sources to 
title V permitting is not impracticable, infeasible, or unnecessarily 
burdensome. Furthermore, if we exempt area sources from title V 
permitting requirements, we would most likely have continued to apply 
RCRA permit requirements for stack emissions to these sources. Thus, 
the area sources would have been subject to dual permitting regimes 
(e.g., federally enforceable state operating permits under the CAA and 
RCRA permits) and the resulting burden associated with duplicative 
regulation. This would be contrary to a major goal of today's rule. In 
conclusion, we decided that it is appropriate to subject all hazardous 
waste combustor sources subject to today's MACT standards to title V 
permitting requirements. As noted earlier in this preamble, this is 
also consistent with the Congressional scheme under RCRA that mandates 
regulation of all hazardous waste combustors for all pollutants of 
concern.
    Although we provided the option to defer title V permitting for 
some area sources subject to other MACT standards, this rule is not the 
first time we have not allowed States to defer area sources from title 
V requirements. See, e.g., 64 FR 31898, 31925 (June 14, 1999) (NESHAP 
for Portland Cement Manufacturing Industry to be codified at

[[Page 52981]]

40 CFR part 63, subpart LLL). Moreover, EPA regulations governing other 
categories of solid waste combustors under CAA section 129 do not 
differentiate between major and minor sources in imposing title V 
permitting requirements. See, e.g., CAA section 129(e); 40 CFR 70.3(a) 
and 70.3(b)(1), and 40 CFR 60.32e(i). Given that the decision to apply 
title V requirements is made in a specific context, we do not share 
commenters' concern about the precedent our approach might set for 
other situations. We will continue to evaluate each situation on its 
own merit. Finally, we do not agree with commenters that this approach 
will provide a disincentive to limit emissions because sources will 
still be ``capped'' by the emissions limits being promulgated in 
today's rule. Neither would progress already achieved in developing 
federally enforceable state operating permits be rendered meaningless, 
as suggested by some commenters. We anticipate that a source will 
likely be able to use the information gathered during the process of 
developing a federally enforceable state operating permit (e.g., 
information about its emissions and applicable requirements) in 
completing a title V application. Commenters appear to think that 
sources will have to start totally anew and without an ability to use 
past experience and results. This is neither a realistic nor practical 
view of how sources are likely to act.
    Commenters opposed to subjecting hazardous waste combustor area 
sources to title V had also noted that these sources would be receiving 
RCRA permits for the air emissions as well. This argument would have 
merit if we choose to promulgate the new standards in both CAA and RCRA 
regulations. Since we are promulgating the MACT standards only in the 
CAA regulations, however, requirements on air emissions from hazardous 
waste combustor area sources would not be included in RCRA 
permits.298 Commenters also discount our position in the 
NODA about difficulties that would arise if an area source were to move 
from one permitting program to another as they make modifications to 
their emissions levels that could change their major/area source 
determination. They point to our ``once in, always in'' approach to 
MACT standards that is stringently applied. Under this approach, once a 
MACT standard goes into effect, a major source will always be regulated 
under that standard, even if it later decreases its emissions to below 
major source levels. This ensures that sources cannot routinely 
``flip'' between being regulated or unregulated, which in turn means 
that sources would not be moving in and out of the title V permitting 
universe. The commenter was correct in raising this to our attention. 
We are not relying on this argument to support our decision to subject 
hazardous waste combustor area sources to the standards or to title V.
---------------------------------------------------------------------------

    \298\ The exception would be, as discussed earlier, cases where 
States, at their own choosing, have incorporated the HWC MACT 
standards into their State RCRA programs.
---------------------------------------------------------------------------

D. How will Sources Transfer from RCRA to MACT Compliance and Title V 
Permitting?
1. In General, How Will this Work?
    As discussed in Section A (Placement of Standards and Approach to 
Permitting), we are deferring RCRA controls on hazardous waste 
combustor air emissions to the part 63 hazardous waste combustor MACT 
standards, which are ultimately incorporated into title V permits 
issued under the CAA. Promulgation of the new hazardous waste combustor 
MACT standards under the CAA does not, however, by itself implement 
this deferral or eliminate the need to continue complying with 
applicable RCRA requirements--either those in a source's RCRA permit or 
in RCRA interim status performance standards. These requirements 
include obligations for RCRA permitting (for example, interim status 
facilities will continue to be subject to RCRA permitting requirements, 
including trial burn planning and testing).
    Therefore, today's rule adopts specific provisions that address the 
transition from RCRA permitting to the CAA regulatory scheme. As 
discussed in Section B.3 (Applicability of RCRA permitting 
requirements), the requirements in Secs. 270.19, 270.22, 270.62, and 
270.66 do not apply once a source demonstrates compliance with the 
standards in part 63 subpart EEE by conducting a comprehensive 
performance test and submitting an NOC to the regulatory 
agency.299 In this section, we discuss how regulators can 
implement the deferral from RCRA to hazardous waste combustor MACT 
compliance and title V permitting.
---------------------------------------------------------------------------

    \299\ If, however, there is a need to collect information under 
Sec. 270.10(k) then the permitting authority may require, on a case-
by-case basis, that facilities use the provisions found in these 
sections.
---------------------------------------------------------------------------

    a. What Requirements Apply Prior to Compliance Date? You have three 
years following promulgation of the MACT standards to achieve 
compliance with the emissions standards. However, the rule is effective 
shortly after promulgation. During the approximately three years 
between the effective date and the compliance date, you will be subject 
to applicable requirements for hazardous waste combustor MACT 
compliance and title V permitting. For example, there are compliance-
related requirements in 40 CFR part 63 subpart EEE that are separate 
from the actual standards for emissions levels, such as those in 
Secs. 63.1210(b) and 63.1211(b) for submitting a Notice of Intent to 
Comply and a progress report, respectively. Requirements in 40 CFR 
parts 70 and 71 for operating permit programs developed under title V 
will also apply. These include requirements governing timing for 
submitting initial applications, reopenings to include the standards, 
and revisions to incorporate applicable requirements into title V 
permits. The interface between an NOC and the title V permit has 
already been discussed. Consequently, our discussion on implementing 
the deferral of RCRA controls focuses on the transition away from RCRA 
permits and permit processing once a facility demonstrates compliance 
with the standards through a comprehensive performance test and submits 
a NOC to the regulatory agency.
    Many of the activities undertaken during the three year compliance 
period play a role in implementing the transition of RCRA controls to 
MACT compliance and title V. For example, some of you may have to make 
changes to their design or operations to come into compliance with the 
new standards. If you have a RCRA permit, you may need to modify the 
RCRA permit to reflect any of these changes before they are actually 
made. This may be necessary to remain in compliance with the RCRA 
permit while setting the stage for demonstrating compliance with CAA 
MACT requirements. We urge you (the source) to seek guidance from your 
RCRA permitting authorities as early as possible in this process. As 
part of our ``fast track rule'' (see 63 FR 33781, June 19, 1998), we 
promulgated a streamlined process in 40 CFR 270.42(j) for modifying the 
RCRA permit, so that you can make these necessary changes and begin 
operating in accordance with the new limits before the compliance date 
arrives. To take advantage of the streamlined process, however, you 
must first comply with the Notice of Intent to Comply requirements in 
Sec. 63.1210. The Notice of Intent to Comply requirements obligate you 
to advertise and conduct an informal meeting with the neighboring 
community to discuss plans to comply with the new standards, and to 
subsequently provide information about

[[Page 52982]]

these plans to the regulatory agency.300 We anticipate 
discussion at this meeting will include modifications to the RCRA 
permit that must be processed before you can start upgrading equipment 
to meet the emissions limits set by MACT. The goal of these activities 
is to ensure that by the end of the three-year compliance period, you 
will be in compliance with both the MACT standards and their RCRA 
permits or interim status requirements.
---------------------------------------------------------------------------

    \300\ The requirements for providing notice of and conducting 
the public meeting as part of the Notice of Intent to Comply 
provisions are based on the RCRA preapplication meeting requirements 
in 40 CFR 124.31.
---------------------------------------------------------------------------

    b. What Requirements Apply After Compliance Date? After the 
compliance date, a transition period exists during which there will be, 
in effect, two sets of standards concerning emissions from hazardous 
waste combustors: (1) The MACT standards in 40 CFR part 63; and (2) the 
performance standards that are still in the RCRA permit or in the 40 
CFR part 265 interim status regulations. During this period, in cases 
where operating parameters and limits are addressed by both programs 
(MACT and RCRA), you must comply with all applicable parameters and 
limits; those which are more stringent will govern. We anticipate that 
the MACT standards will be compatible with the RCRA performance 
standards, although in some cases the DOC is likely to set narrower or 
different operating conditions. Thus, in complying with the MACT 
standards, you also will comply with corresponding conditions in the 
RCRA permit or in the RCRA interim status regulations. However, at some 
sites, certain RCRA permit conditions may be more stringent than the 
corresponding MACT standards or may establish independent operating 
requirements. Some potential reasons why such a situation would occur 
are discussed in the May 2, 1997 Notice of Data Availability (62 FR 
21249, 5/2/97). In these situations, you must comply with the more 
stringent or more extensive conditions in the RCRA permit.
    We also note that there may be situations where it is not clear 
whether a RCRA compliance requirement is less stringent than a MACT 
requirement. This can occur, for example, when the two compliance 
requirements have different averaging periods and different numerical 
limits. In this situation, we recommend that the source coordinate with 
permitting officials early in the MACT process, perhaps when the source 
submits RCRA permit modification pursuant to the fast-track rulemaking, 
in order to determine which requirement is more stringent. We believe 
the permitting officials should give sources an appropriate level of 
flexibility when making this determination.
    Our approach of placing the MACT air emission standards for 
hazardous waste combustors in 40 CFR part 63 subpart EEE and not 
including them, even by reference, in the RCRA regulations means that 
the air emissions must ultimately be incorporated into title V permits 
issued under the CAA. To completely implement the deferral of RCRA 
controls, conditions governing air emissions and related operating 
parameters should also be ultimately removed from RCRA permits. (For 
the special case of risk-based conditions derived from RCRA omnibus 
authority, see earlier discussions.) Similarly, hazardous waste 
combustors that are in the process of obtaining RCRA permits will 
likely need to have the combustor air emissions and related parameters 
transitioned to MACT compliance and title V permits at some point.
    We intend to avoid duplication between the CAA and RCRA programs. 
We encourage you and regulators to work together to defer permit 
conditions governing air emissions and related operating parameters 
from RCRA to MACT compliance and title V, and to eliminate any RCRA 
provisions that are no longer needed from those permits. As discussed 
below, we are adopting a provision in today's final rule to help 
permitting authorities accomplish this task in the most streamlined way 
possible. The RCRA permits will, of course, retain conditions governing 
all other aspects of the hazardous waste combustor unit and the rest of 
the facility that continue to be regulated under RCRA (e.g., general 
facility standards, corrective action, financial responsibility, 
closure, and other hazardous waste management units). Furthermore, if 
any risk-based site-specific conditions have been previously included 
in the RCRA permit, based either on the BIF metals and/or hydrochloric 
acid/chlorine requirements 301 or the omnibus authority, the 
regulatory authority will need to evaluate those conditions vis-a-vis 
the MACT standards and the operating parameters identified in the NOC. 
If the MACT-based counterparts do not adequately address the risk in 
question, those conditions would need to be retained in the RCRA permit 
or included within an appropriate air mechanism. In those limited 
cases, sources and permitting agencies may instead agree to identify 
the RCRA limit in the title V permit. Since one goal of the title V 
program is to clarify a source's compliance obligations, it will be 
beneficial, and convenient, to acknowledge the existence of more 
stringent limits or operating conditions derived from RCRA authority 
for the source in the title V permit, even though the requirements 
would not reflect CAA requirements. We strongly encourage Regional, 
State, and local permitting authorities to take advantage of this 
beneficial option.
---------------------------------------------------------------------------

    \301\ The BIF limits for metals under RCRA are based on 
different level of site-specific testing and risk analysis (Tier I 
through Tier III). It is possible that, if it were based on the more 
stringent analysis, a RCRA BIF limit could be more stringent than 
the corresponding MACT standard.
---------------------------------------------------------------------------

2. How Will I Make the Transition to CAA Permits?
    In the May 1997 NODA, we expressed our intent to rely on the title 
V permitting program for implementation of the new standards, and asked 
for comments on how and when the transition from RCRA should occur (see 
62 FR 24250, May 2, 1997). We are amending the regulations in 40 CFR 
part 270 to specify the point at which the RCRA regulatory requirements 
for permitting would cease to apply. However, once you have a permit, 
you must comply with the conditions in that permit until they are 
either removed or they expire. Many commenters expressed an interest in 
what happens to conditions in a RCRA permit once the new standards are 
published. We received a variety of suggestions, but a common thread 
was a request for EPA to lay out a clear path through the permit 
transition process. While we recognize the desirability of having a 
uniformly defined route for getting from one permit to another, it is 
important to provide flexibility to allow a plan that makes the most 
sense for the situation at hand. There is not a ``one size fits all'' 
approach that would be appropriate in all cases. Thus, we are not 
prescribing a transition process via regulation, but providing guidance 
in the following discussion which we hope will assist regulatory 
agencies in determining a route that makes the most sense in a given 
situation. Given the level of interest expressed, we will, in the 
ensuing discussion, map out a process for implementing the deferral of 
air emissions controls from RCRA to MACT compliance and title V 
permitting. We address key considerations that should factor into the 
decision of how and when to implement the deferral of permit 
conditions.302
---------------------------------------------------------------------------

    \302\ Although we are not mandating an approach to transition by 
regulation, we are, as discussed in Section 2. How Should RCRA 
Permit Be Modified? below, providing a tool in the RCRA permit 
modification table in 40 CFR 270.42, Appendix I, that may be used to 
assist regulators and sources in effecting the transition.

---------------------------------------------------------------------------

[[Page 52983]]

    In identifying key aspects of the transition, we seek the optimal 
balance of three basic considerations raised by commenters and other 
stakeholders. The considerations are to: (1) Address public perception 
issues associated with taking conditions out of a RCRA permit; (2) 
minimize the amount of time a source might be potentially subject to 
overlapping requirements of RCRA and the CAA (and thus subject to 
enforcement under both RCRA and the CAA for the same violation); and 
(3) provide flexibility to do what makes the most sense in a given 
situation. The first two considerations are primarily factors of time--
when should conditions be removed from the RCRA permit? The third 
consideration is more a factor of how--what mechanism should be used 
for removing RCRA conditions?
    Why do these particular considerations carry such importance? As 
for the first, one of the points emphasized in our National Hazardous 
Waste Minimization and Combustion Strategy is the importance of 
bringing hazardous waste combustors under permits as quickly as 
possible. The Strategy has been driving EPA Regions and authorized 
States to place their top permitting priority on the hazardous waste 
combustor universe. Consequently, the Strategy may have created a 
certain perception on behalf of the public about the importance of the 
actual permit document. The actual issue we are trying to address here 
is more of a concern about a potential break in regulatory coverage of 
a source as it transitions from RCRA permitting requirements to the CAA 
regulatory scheme.
    While it might appear that we are altering the policy expressed in 
the Strategy if we allow removal of conditions from a RCRA permit 
before the title V permit is in place, it is not the actual permit 
document that is of paramount importance. Rather, our focus is and has 
been on maintaining a complete and enforceable set of operating 
conditions and standards. One of the underlying tenets of the position 
taken on permitting in the Combustion Strategy was a commitment to 
bring hazardous waste combustors under enforceable controls that 
demonstrate compliance with performance standards. Under RCRA, the 
permit was the available vehicle to achieve better enforcement of 
tighter conditions than exist in interim status.
    We remain committed to this underlying tenet. However, the 
mechanism for achieving this objective under the CAA is not necessarily 
the title V permit. In RCRA, the permitting process provides the 
vehicle for the regulatory agency to approve testing protocols 
(including estimated operating parameters), to ensure completion of the 
testing, and to develop final operating parameters proven to achieve 
performance standards. The final RCRA permit is the culmination of 
these activities. Under MACT, these activities do not culminate in a 
permit, but in a NOC. The development of the NOC is separate from the 
development of the title V permit. The title V permitting process is 
primarily a vehicle for consolidating in one document all of the 
requirements applicable to the source. Conversely, it is the NOC that 
contains enforceable operating conditions demonstrated through the 
comprehensive performance test to achieve compliance with the hazardous 
waste combustor MACT standards (which are generally more stringent than 
the RCRA combustion performance standards). Thus, the NOC captures the 
intent of the Strategy with regard to ensuring enforceable controls 
demonstrated to achieve compliance with relevant standards are in 
place.
    Another basis for our position on permitting in the Combustion 
Strategy is the level of oversight by the regulatory agency during the 
permitting process, which is typically greater than that which occurs 
during interim status. For example, although BIFs operating under 
interim status are required to conduct compliance testing and 
subsequently operate under conditions they identify in a certification 
of compliance, there are no requirements for the regulatory agency to 
review and approve compliance test plans or results. On the other hand, 
oversight by the regulatory agency is more intensive during the 
permitting process, e.g., through the trial burn planning (including 
regulatory approval of the trial burn plan), testing, and development 
of permit conditions. Although the process required for interim status 
BIFs under RCRA may, at first, seem analogous to the CAA MACT process, 
i.e., sources being required to conduct comprehensive performance tests 
and subsequently operate under conditions in an NOC, there is a 
significant difference. The difference is the level of oversight that 
occurs in the MACT process. According to the MACT requirements in 40 
CFR 63.1207(e) and 63.1206(b)(3), the regulatory agency must review and 
approve the performance test protocol and must make a finding of 
compliance based on the test results that are reported in the NOC. The 
NOC consequently represents a level of agency oversight that is 
actually more analogous to the RCRA permit process than to interim 
status procedures.
    An additional reason for the importance, under the Combustion 
Strategy, of bringing hazardous waste combustors under permits was to 
allow for the imposition of additional permit conditions where 
necessary to protect human health and the environment. In general, 
these conditions are established based on the results of a site-
specific risk assessment and imposed under the RCRA omnibus authority. 
This objective will continue to be met even though we are deferring 
regulation of hazardous waste combustor air emissions, in general, to 
the CAA. Coming into compliance with the more stringent and more 
encompassing MACT standards will accomplish part of the Combustion 
Strategy's goal of improved protection. For any cases where the 
protection afforded by the MACT standards is not sufficient, the RCRA 
omnibus authority and RCRA permitting process will continue to be used 
to impose additional conditions in the RCRA permit (or, as discussed 
earlier, in a title V permit).
    With regard to the remaining considerations, we seek here to reduce 
duplicative requirements across environmental media programs (i.e., air 
emissions under the CAA and RCRA). This objective to reduce duplication 
is behind our goal of minimizing the amount of time a source might be 
potentially subject to dual permitting and enforcement scenarios. In 
order to allow for common sense in implementing environmental 
regulations, we need to provide flexibility here to do what makes sense 
in a given situation. We have provided this flexibility in today's rule 
by not prescribing only one process for transitioning from RCRA to the 
CAA.
3. When Should RCRA Permits Be Modified?
    We identified two options in the May, 1997, NODA for when 
conditions should be ultimately removed from RCRA permits (see 62 FR 
24250). Our preferred option at the time is to wait until the source 
had completed its comprehensive performance test and the standards had 
been included in its title V permit. The alternative option we 
identified would be to modify the RCRA permit once the facility submits 
the results of its comprehensive performance test.

[[Page 52984]]

    Of the comments that spoke to the timing issue, some advocate 
waiting for the title V permit, but most opposed this position. The 
majority of commenters favor effecting the transition either on the 
compliance date, since we had said in the NODA that the pre-NOC would 
be due to the regulatory agency on that date 303 and would 
contain enforceable conditions, or upon submittal of the NOC, since it 
contains enforceable operating conditions demonstrated to achieve 
compliance with the standards. All three of these approaches are 
identified in the time line shown in Figure 1. Readers will note that 
the time line shows two potential points for the title V permit to be 
issued (options 1A and 1B). Option 1A is based on the statutory time 
frames for issuing title V permits. Under this option, the title V 
permit may be issued prior to the compliance date for the new 
standards, but it might only include the standards themselves and a 
schedule of compliance. Under option 1B, the operating requirements in 
the NOC that actually have been demonstrated to achieve compliance 
would be included in the permit.
---------------------------------------------------------------------------

    \303\ We are adopting a DOC (previously the pre-NOC) requirement 
in today's final rule, but it is amended from how we presented it in 
the NODA (as discussed in Part Five, Section IV). Rather than 
submitting the DOC to the regulatory agency, a source must maintain 
it in their operating record. We encourage source owners and 
operators to set up the operating record in an unrestricted location 
that is reasonably accessible by the public.
---------------------------------------------------------------------------

    We evaluated each of the options in terms of the two timing-related 
considerations listed above: addressing the perception issue that stems 
from removing conditions from the RCRA permit (which, as discussed 
above, is really a concern about a break in regulatory coverage--i.e., 
that there might be a period of time when the source would not have 
enforceable controls demonstrated to achieve compliance with stack 
emissions standards), and minimizing the amount of time sources would 
potentially be subject to the same requirement(s) under both RCRA and 
CAA. These considerations may not always be compatible. For example, 
one way to address the perception of creating a break in regulatory 
coverage would be to continue to place emphasis on the permit, rather 
than on the tenet behind the permit (of having enforceable controls 
that demonstrate compliance with performance standards). This would 
mean waiting to remove conditions from a RCRA permit until a source has 
demonstrated compliance with the MACT standards and incorporated the 
appropriate combustion operating requirements in its NOC into the title 
V permit (i.e., option 1B). However, this approach would maximize the 
amount of time the source potentially would be subject to overlapping 
requirements under RCRA and the CAA. On the other hand, one way to 
address the overlapping requirements consideration would be to allow 
removal of conditions from the RCRA permit at the time the standards 
are promulgated. But, this would create a time period during which the 
source would not have enforceable controls proven to achieve 
compliance, which would not address the concern about avoiding a break 
in regulatory coverage. Clearly neither of these extremes can provide a 
good balance between the two timing-related considerations.

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[GRAPHIC] [TIFF OMITTED] TR30SE99.007



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[[Page 52987]]

    We evaluated each option to determine which most effectively 
balances the relevant issues. Options 1A and 1B focus primarily on 
tying the transition timing to title V permitting. Option 2 links the 
timing for transition to the DOC (previously called the pre-NOC). 
Option 3, which we are recommending be followed, ties transition to 
submittal of the NOC.
    a. Option 1A. This option is a variation of an option discussed in 
the May, 1997, NODA. There we stated, ``The Agency's current thinking 
is that the RCRA permit should continue to apply until a facility 
completes its comprehensive performance testing and its title V permit 
is issued (or its existing title V permit is modified) to include the 
MACT standards. The RCRA permit would then be modified to remove the 
air emissions limitations which are covered in the title V permit.'' 
(see 62 FR 24250). Although this description basically applies to 
option 1B, the discussion in the NODA might also have been interpreted 
to mean that once the standards are in a title V permit, the 
corresponding emissions limits should be removed from the RCRA permit. 
When reviewing the implementation time line in terms of the statutory 
and regulatory time frames governing the title V process, we found that 
sources might well have title V permits issued or modified to include 
the new standards a year before they ever conduct performance testing. 
Although the permit would likely include the standards and a schedule 
for complying with the new limits, it would not include any of the key 
combustion operating requirements demonstrated in the performance test. 
Thus, even though option 1A would seem to address the concern about a 
break in coverage because the title V permit would have been issued, in 
actuality, the underlying tenet of the Combustion Strategy--that the 
source have enforceable operating parameters proven to achieve the new 
standards--is not fully addressed.
    b. Option 1B. This option calls for the NOC to be incorporated into 
title V permits before any conditions could be removed from RCRA 
permits. As discussed earlier, this approach would not be consistent 
with our goal of minimizing duplication across permitting programs, 
even though it was identified as our current thinking in the NODA. As 
discussed in the NOC/title V Interface Section, the initial NOC must be 
incorporated into the title V permit as a significant permit 
modification, which could add another nine months to the transition 
period. Moreover, commenters express concern over impacts that existing 
delays in title V permitting activities might have. Commenters wrote 
that given the tremendous volume of permits to be issued (hazardous 
waste combustors being just one small subset) there would be no way to 
predict how long it might take regulatory agencies to initially issue 
or modify title V permits to include the standards, or to modify 
permits to include NOCs, despite time frames set forth in the title V 
regulations. We agree that delaying removal of air emissions and 
related parameters from RCRA permits until this occurs would 
unnecessarily extend the amount of time sources might be subject to 
overlapping requirements. As pointed out by commenters, having 
overlapping requirements may present technical and administrative 
difficulties. Examples of technical difficulties include, but are not 
limited to, the potential for conflicting requirements with regard to 
testing, monitoring, and compliance certifications. Examples of 
administrative difficulties include, but are not limited to, permit 
maintenance issues stemming from different permit modification 
procedures and appeals procedures.
    c. Option 2. Option 2 reflects the time frame suggested by some 
commenters for effecting the transition upon submittal of the DOC, 
which, under the NODA discussion, would have been due to the regulatory 
agency on the compliance date (note: commenters appear to use the terms 
``compliance date'' and ``effective date'' interchangeably, but they 
are quite different). Basing transition on the DOC was still a viable 
option to consider, even with our amended approach of having the source 
maintain the DOC in its operating record. The DOC contains enforceable 
operating conditions for key combustion parameters that the source 
anticipates will achieve compliance with the new standards. Although 
the source would have had to comply with other enforceable part 63 
requirements by this point (e.g., requirements for the Notice of Intent 
to Comply, the progress report, and the performance test plan), this 
would be the first point where a source might have overlapping 
requirements governing air emissions and related operating parameters--
those in the DOC and those in the RCRA permit. Recommending removal of 
RCRA permit conditions at this point would thus minimize the potential 
for duplicative requirements. However, we conclude that it would still 
not address the perception issue adequately. Specifically, even though 
the source is subject to enforceable operating requirements, the source 
has not actually demonstrated compliance with the new standards.
    d. Option 3. This option reflects the alternative approach we 
suggested in the May, 1997, NODA, as well as the preferred option of 
the majority of those who submitted comments on the timing issue. Under 
this recommended option, a source might well have a title V permit that 
addresses the new standards to some extent, even if just by including 
the standards themselves and a schedule for compliance. More 
importantly, the source will have conducted its comprehensive 
performance test, and submitted an NOC containing key operating 
parameters demonstrated to actually achieve compliance (and which are 
enforceable). Although there would be some time during which a source 
might have overlapping requirements (those in its NOC and those in its 
RCRA permit), this would be a finite and predictable amount of time. 
After considering all the comments, we conclude that option 3 best 
meets the dual challenges of ensuring the source is continuously 
subject to enforceable controls demonstrated to achieve compliance 
while minimizing the time you would be subject to permitting 
requirements for, and enforcement of, operating parameters and limits 
under both RCRA and the CAA. Therefore, today's rule adopts option 3.
    We acknowledge that this approach does not completely eliminate 
concerns expressed by some commenters about the potential for 
facilities to be subject to dual enforcement mechanisms. Although this 
potential may exist during the brief transition period when a source 
has enforceable conditions under both CAA and RCRA, we will exercise 
enforcement discretion to avoid any duplicative inspections or actions, 
and we encourage States to do so as well. If any inspections are 
scheduled to occur during the brief transition period (which may be 
unlikely given how short this period is), the regulatory agency could 
conduct joint inspections by RCRA and CAA enforcement staff. Joint 
inspections might help to alleviate some of the potential for any 
duplicative efforts, either in terms of individual inspections 
targeting the same areas, or enforcement actions being taken under both 
RCRA and CAA authorities.
    Under Option 3, you would most likely have a title V permit that 
addresses the hazardous waste combustor MACT standards to some extent. 
We expect that if the permit were issued prior to the comprehensive 
performance test and the submittal of the NOC, it would contain the 
standards

[[Page 52988]]

themselves, and related requirements in part 63 subpart EEE, such as 
the requirements to develop and public notice performance test 
protocols, to develop and maintain in its operating record the DOC with 
anticipated (and enforceable) operating limits, to conduct the 
comprehensive performance test and periodic confirmatory tests, and to 
submit the NOC, including the test results, to the regulatory agency.
    The public would have had an opportunity to comment on the 
requirements in the title V permit as part of the normal CAA 
administrative process for issuing permits. Furthermore, the public 
would have had other opportunities to be involved in your compliance 
planning. For example, under the requirements for the Notice of Intent 
to Comply in Sec. 63.1210(b), you would have had to conduct an informal 
meeting with the community to discuss how you intend to come into 
compliance with the new standards. You also are required in 
Sec. 63.1207(e) to provide public notice of the performance test plan, 
so the public would have the opportunity to review the detailed testing 
protocol that describes how the operating parameters will achieve 
compliance.
4. How Should RCRA Permits Be Modified?
    Once you have been issued a RCRA permit, you must comply with the 
conditions of that permit. Unless the conditions have been written into 
the permit with sunset (i.e., automatic expiration) clauses governing 
their applicability, conditions remain in effect until the permit is 
either modified to remove them or the permit is terminated or expires. 
Promulgation of final MACT standards for hazardous waste combustors 
does not in itself eliminate your obligation to comply with your RCRA 
permit. In the May 1997 NODA, we stated that the RCRA permit would be 
modified to remove air emission limitations that are covered under 
MACT, but did not elaborate on what modification procedures would be 
followed. We solicited comments on how the transition should occur.
    Of the commenters that addressed this issue, the recurring theme in 
the comments is for EPA to provide a mechanism that would impose 
minimal burden on sources and permit writers to process the 
modifications. Some express a desire to see the RCRA conditions removed 
in some automatic fashion once the MACT standards became effective. A 
mechanism for accomplishing this, suggests one commenter, would be to 
include a requirement in the final rule that would effect removal of 
conditions from all RCRA permits. One commenter suggests adding a new 
line item to Appendix I in Sec. 270.42, designated as class 1, to 
address the transition to MACT. Another suggests a new line item 
designated as class 1 requiring prior agency approval. A third suggests 
a new line item designated as class 2.
    We do not agree with eliminating conditions from all RCRA permits 
as part of a national rulemaking effort (i.e., we do not agree with an 
``automatic'' removal), particularly given the existence of authorized 
sate programs and state-issued permits. Permits may contain site-
specific conditions developed to address particular situations, e.g., 
conditions based on the results of a site-specific risk assessment. To 
ensure that the regulatory agency continues to meet its RCRA obligation 
to ensure protection of human health and the environment, these 
conditions may need to be evaluated on a case-by-case basis vis-a-vis 
the MACT standards before they are removed. If the RCRA risk-based 
conditions are more stringent or more extensive than the corresponding 
MACT requirements, the conditions must remain in the RCRA permit.
    We do agree with commenters that there should be a streamlined 
approach to removing conditions from a RCRA permit that are covered by 
the hazardous waste combustor MACT regulations at the time an NOC 
demonstrating compliance is submitted to the regulatory agency. All 
other conditions would, of course, remain in the RCRA permit. Once you 
demonstrate compliance with MACT, we consider the transition from RCRA 
to be primarily an administrative matter since you will not only be 
subject to comparable enforceable requirements under CAA authority, but 
also will continue to be subject to any site-specific conditions under 
RCRA that are more stringent than MACT. Our intent is not to impose an 
additional burden on you or permit writers for a largely administrative 
requirement. To this end, we are adding a new line item to the permit 
modification table in 40 CFR 270.42, Appendix I, to specifically 
address the transition from RCRA to the CAA.
    The approach of adding a new line item to the permit modification 
table is consistent with the comments we received pursuant to the May 
1997 NODA. We agree with the commenter who suggests the new item be 
designated as a class 1 modification requiring prior Agency approval. 
This classification effectively balances the need to retain some 
regulatory oversight of the changes with the goal of minimizing the 
amount of time a source will be subject to regulation under both RCRA 
and the CAA for essentially the same requirements. A class 1 
modification without prior approval, suggests one commenter, would not 
be sufficient to accomplish the transition with adequate confidence in 
proper regulatory coverage. Even though we consider the deferral to be 
an administrative matter, it is important to retain some level of 
regulatory oversight prior to effecting the change to provide the 
opportunity to address any differences between the two programs. On the 
other hand, the administrative exercise of transitioning from RCRA to 
the CAA does not warrant the extra measures (and attendant time 
commitment) of a class 2 modification procedure.
    We are designating the new line item (A.8.) in the Appendix I table 
as class 1 requiring prior Agency approval. Thus, the administrative 
procedures associated with this mechanism will not be overly 
burdensome, yet RCRA permit writers will have an opportunity to confer 
with their counterparts in the air program prior to approving the 
request to eliminate conditions from the RCRA permit. This allows the 
RCRA permit writer to verify that you have completed the comprehensive 
performance test and submitted your NOC. In the few situations where 
site-specific, risk-based conditions have been incorporated into RCRA 
permits, it also provides the RCRA permit writer with the opportunity 
to review such conditions vis-a-vis the MACT standards to ensure any 
conditions that are more stringent or extensive than those applicable 
under MACT are retained in the RCRA permit. The public also would be 
informed that the transition from RCRA was being effected because the 
modification procedures require a notice to the facility mailing list. 
We recommend that the public notice for the RCRA permit modification 
also briefly mention that you have completed performance testing under 
the CAA, and are operating under enforceable conditions that are at 
least as stringent as those being removed from your RCRA permit.
    One commenter offered suggestions for preparing the RCRA 
modification requests. We found some of these suggestions helpful and 
recommend that, to facilitate processing of the RCRA modification 
requests, you (1) identify in your modification requests which RCRA 
conditions should be removed, and (2) attach your NOC to the requests.
    From another perspective, today's approach for removing conditions 
from the RCRA permit also may encourage

[[Page 52989]]

you to work closely with the air program to expeditiously resolve any 
potential or actual disagreements on the results of the comprehensive 
performance test and conditions in the NOC. The RCRA permit writer is 
not likely to approve the modification request until he or she has 
received confirmation that their air program counterpart is satisfied 
with your compliance demonstration under MACT (i.e., that they have 
made the finding of compliance based on the test results documented in 
the NOC, as discussed in the following paragraph). Thus, you should 
continue to be subject to requirements under both RCRA and the CAA 
until the differences, if any, are resolved.
    We are not including a requirement in either part 63 subpart EEE or 
part 270 specifically for the regulatory agency to approve the NOC 
before approving the RCRA modification request. We have incorporated 
the general provision for making a finding of compliance (see 
Sec. 63.6(f)(3)) into the requirements of subpart EEE at 
Sec. 63.1206(b)(3). According to these provisions, the regulatory 
agency has an obligation to make a finding of compliance with 
applicable emissions standards upon obtaining all of the compliance 
information, including the written reports of performance test results. 
Because of this obligation, air program staff currently review stack 
test results that are submitted in NOCs subsequent to performance 
testing, and routinely transmit an official letter to you indicating 
the acceptability of the test results. Furthermore, if you fail the 
comprehensive performance test, there are requirements in part 63 
subpart EEE specifying what you must then do. Given this combination of 
regulatory obligations and current practices, we see no need to impose 
additional requirements governing review of performance test results. 
This approach is also consistent with the timing for when permit 
requirements are deferred to CAA (see the amended rule language for 40 
CFR 270.19, 270.22, 270.62, and 270.66)).
5. How Should Sources in the Process of Obtaining RCRA Permits Be 
Switched Over to Title V?
    In the initial NPRM and the May, 1997, NODA, we did not 
specifically describe, or solicit comment on, permit process issues for 
facilities operating under RCRA interim status, or facilities seeking 
to renew their RCRA permits (which can occur even after the nominal 
permit term has expired). In the above sections, we focused on 
implementing the deferral of RCRA controls by determining how and when 
to move conditions out of existing RCRA permits. For facilities that do 
not yet have RCRA permits, or that need to renew their RCRA permits, 
the focus of the discussion shifts to how and when to move nonrisk-
based air emissions considerations out of the RCRA permitting process. 
As indicated earlier, RCRA interim status facilities will continue to 
be subject to RCRA permitting requirements for air emissions standards 
and related operating parameters, including trial burn planning and 
testing, until they have demonstrated compliance with the new standards 
by conducting a comprehensive performance test and submitting an NOC to 
the agency. Facilities in the process of renewing their RCRA permits 
will also continue to be subject to RCRA permitting requirements until 
the same point.
    Again, there is no single approach for moving these two categories 
of facilities out of the RCRA permitting process (i.e., for stack air 
emissions requirements). The most appropriate route to follow in each 
case depends on a host of factors, including, for example: (1) The 
status of the facility in the RCRA permitting process at the time this 
rule is published; (2) the priorities and schedule of the regulatory 
agency; (3) the level of environmental concern at a given site; and (4) 
the number of similar facilities in the permitting queue. The 
regulatory agency (presumably in coordination with the facility) will 
balance all of these factors. In mapping out a site-specific approach, 
we are encouraging permitting agencies to give weight to two key 
factors. First, we should minimize to the extent practicable the amount 
of time a facility would be subject to duplicative requirements between 
RCRA and CAA programs. Second, as indicated in Part Five, Section V.B 
(Risk Burn/Comprehensive Performance Testing), testing under one 
program should not be unnecessarily delayed in order to coordinate with 
testing under the other. For example, if a facility is planning to 
conduct a RCRA trial burn within a fairly short amount of time after 
the rule is promulgated, they generally should not be allowed to delay 
the trial burn to coordinate with comprehensive performance testing 
under MACT that may not occur for three more years.\304\
---------------------------------------------------------------------------

    \304\ There may be a short delay allowed for the purpose of 
combining RCRA trial burn and MACT performance test plans. Of 
course, even if the timing for the two tests is such that they may 
be coordinated, that does not mean that one can simply replace the 
other, particularly because test conditions for one may not be 
applicable to the other (refer to Section V.B for additional 
discussion on this topic).
---------------------------------------------------------------------------

    Even though we cannot prescribe a single national approach for the 
transition from RCRA permitting for air emissions, we can provide some 
other recommendations to help permitting authorities and facility 
owners or operators determine a sound approach. In this section, we 
walk through some examples, intended as guidance, for transitioning 
facilities that are in the process of obtaining or renewing a RCRA 
permit. We hope that these examples will also enhance consistency among 
the various regulatory agencies.
    a. Example 1. Facility has submitted a RCRA permit renewal 
application. Some sources, particularly hazardous waste incinerators, 
have RCRA permits that are close to expiring. These sources may already 
have initiated the renewal process by the time this rule is 
promulgated. In these situations, we anticipate the source might need 
to modify its current permit to accommodate any upgrades necessary to 
comply with the new standards. Facilities may modify RCRA permits that 
have been continued under Sec. 270.51 pending final disposition of the 
renewal application. Thus, facilities will be able to use the 
streamlined permit modification procedures that were promulgated in 
Sec. 270.42(j) to effect the necessary changes pending resolution of 
their renewal application. Depending on where they are in the renewal 
process, the permitting authority may, alternatively, elect to fold the 
modifications into the actual renewal process, thereby streamlining 
some of the administrative requirements.
    Issuance of RCRA hazardous waste combustor permits often takes 
several years. If the source and the permitting authority are in the 
early stages of renewal, the schedule of permitting activities may not 
call for a trial burn to be conducted until sometime close to when the 
source would be required to conduct comprehensive performance testing 
under MACT. If so, the source may be able to either coordinate the 
testing requirements of the two programs, e.g., if a RCRA risk burn is 
necessary, or to perform just the comprehensive performance test under 
MACT. If, on the other hand, they are further along in the renewal 
process, the trial burn might be scheduled for the near future. In this 
case, the approach outlined in Example 2 below might be more 
appropriate to follow.
    Regardless of the approach followed to transition the air emissions 
and related operating parameters for the combustion unit to the Air 
program, the

[[Page 52990]]

RCRA permit must still be renewed for all other aspects of hazardous 
waste management at the facility.
    b. Example 2. Permitting authority has approved, or is close to 
approving, the RCRA trial burn plan at the time the final MACT 
standards are promulgated. Both interim status facilities and those 
seeking permit renewal are subject to requirements in Secs. 270.62 and 
270.66 to develop and obtain approval for trial burn plans. 
Requirements in these sections also call for permitting authorities to 
provide public notice of approved (or tentatively approved) trial burn 
plans and projected schedules for conducting the burns. We anticipate 
that many of the hazardous waste combustors seeking permits who are 
subject to this rulemaking will have already had their trial burn plans 
approved, or close to being approved, by the time this rule is 
promulgated. In such situations, we expect the facility to continue 
with the trial burn as planned.
    If the burn is successful, we anticipate the permitting authority 
will issue a final RCRA permit that covers both the operations of the 
hazardous waste combustor unit as well as all other hazardous waste 
management activities at the site. We recommend that the permit be 
worded flexibly to facilitate transition to title V once the source 
subsequently demonstrates compliance with the MACT standards. For 
example, conditions in the RCRA permit that would ultimately be covered 
under title V might have associated sunset provisions indicating that 
the conditions will cease to apply once the combustor unit demonstrates 
compliance with the MACT standards. This would ensure that the amount 
of time the source might be subject to emissions limits and operating 
parameters under both RCRA and the CAA would be minimized. It would 
also eliminate the need to engage in a separate permit modification 
action to remove the conditions after the MACT compliance 
demonstration.
    Facilities in this scenario may determine they need to make some 
changes to their equipment or operations to meet the new emissions 
limits. These facilities will be able to use the streamlined permit 
modification procedures that were promulgated in Sec. 270.42(i).
    If the trial burn is not successful, we expect permitting 
authorities to refer to the RCRA trial burn failure policy (see 
Memorandum on Trial Burns, EPA530-F-94-023, July 1994). This policy 
includes discussion in the following areas: (1) Taking immediate steps 
to restrict operations; (2) initiating procedures for permit denial 
(which would be appropriate for interim status or renewal candidates); 
(3) initiating proceedings to terminate the permit (which would be 
appropriate for proposed new facilities); and (4) authorizing trial 
burn retesting after the facility investigates reasons for the failure 
and makes changes to address them.
    c. Example 3. The permitting authority does not anticipate 
approving the trial burn plan, or the trial burn is not scheduled to 
occur until after the Notice of Intent to Comply is submitted. As 
suggested in the previous example, if a facility is ready to proceed 
with a trial burn at the time the final hazardous waste combustor MACT 
rule is promulgated, we expect that activities will proceed as planned. 
Once the Notice of Intent to Comply is submitted, however, the 
regulatory authority will have a better understanding of how and when 
the facility intends to comply with the emissions standards, and how 
the trial burn would fit in with the MACT compliance demonstration. 
Thus, we expect the regulatory authority may wish to decide whether to 
separately continue with the trial burn schedule laid out in the RCRA 
permitting process or, conversely, coordinate with MACT comprehensive 
performance testing, based on a number of considerations, including, 
for example: (1) The facility's schedule and planned modifications for 
MACT compliance; (2) progress on completing and approving the RCRA 
trial burn plan; (3) whether the risk testing that may be necessary 
under RCRA is likely to fit in with the MACT performance test schedule; 
and (4) whether the facility wants to combine risk testing under RCRA 
with the MACT performance test.
    Even after a source conducts its comprehensive performance test and 
subsequently submits the NOC to the regulatory agency, separate risk 
testing might be necessary. For example, if the comprehensive 
performance test did not generate sufficient data for a site-specific 
risk assessment, a RCRA ``risk burn'' might be required (see discussion 
in Part Five, Section V.B.).
E. What Is Meant by Certain Definitions?
    When we considered incorporating MACT standards into both RCRA and 
CAA regulations, we anticipated some confusion about definitions that 
differ between the two programs. In the NPRM, we solicited comments on 
our expressed preference not to reconcile these issues on a national 
basis. (See 61 FR 17452). Several commenters suggest that EPA reconcile 
the issues and clarify definitions. In the final rule, we have made 
some changes, as discussed below, to ensure consistency of 
interpretation and to minimize uncertainty for facilities seeking to 
comply with today's rule. With these changes, we believe that revisions 
to the definitions themselves are not necessary.
1. Prior Approval
    In the proposed rule, we stated that RCRA and CAA are similar in 
that they both require EPA prior approval before construction or 
reconstruction of a facility. There were no adverse comments received 
regarding this statement. The requirements for obtaining prior approval 
are apparently clear under both programs.
    We suggested in the proposed rule that readers of part 63 might be 
unaware of their obligations under RCRA. Therefore, as proposed, we are 
inserting the following note into Sec. 63.1206 Compliance Dates, ``An 
owner or operator wishing to commence construction of a hazardous waste 
incinerator or hazardous waste-burning equipment for a cement kiln or 
lightweight aggregate kiln must first obtain some type of RCRA 
authorization, whether it be a RCRA permit, a modification to an 
existing RCRA permit, or a change under already existing interim 
status. See 40 CFR part 270''. No adverse comments were submitted.
2. 50 Percent Benchmark
    As stated in the proposed rule, RCRA and CAA both classify 
``reconstruction'' as any modifications of a facility that cost more 
than 50 percent of the replacement cost of the facility. However, the 
significance of this term is different depending on which statute is 
being applied. Two commenters confirmed that the distinction is 
critical. Therefore, they concluded that, to avoid confusion, EPA 
should defer to the CAA definition of ``reconstruction'' under RCRA 
Section 1006(b) because it is the more flexible and appropriate 
definition.
    The primary concern about the 50 percent benchmark is in relation 
to the limit imposed on RCRA interim status facilities for making 
modifications. To ensure that this limit would not present a barrier to 
making upgrades necessary to comply with MACT, we finalized a revision 
to Sec. 270.72(b) to specify that interim status facilities can exceed 
the 50 percent limit if necessary to comply with MACT. (See 63 FR 
33829, June 19, 1998). Therefore, there is no potential for practical 
conflict among the CAA and RCRA regulatory regimes, and no further 
amendment or clarification is needed.

[[Page 52991]]

3. Facility Definition
    As stated in the NPRM, the definition of ``facility'' differs 
between CAA and RCRA. The definition has bearing in determining the 
value of the facility with respect to the 50 percent rule on 
modifications as discussed above. We proposed that the RCRA definition 
should be used for the RCRA application to changes during interim 
status, and the CAA definition should be used when determining 
applicability of MACT standards to new versus existing sources. 
Commenters disagreed with this approach and concluded that EPA should 
defer to the CAA definition of facility because it encompasses the 
entire operations at a site. We continue to believe that the CAA 
definition should apply to CAA requirements and that the RCRA 
definition should apply to RCRA requirements, since the definitions are 
used for a different purpose under each statute. By clarifying the 50 
percent benchmark issue for RCRA interim status facilities as discussed 
above, we believe this satisfies commenters' concerns and, thus, it is 
not necessary to reconcile the facility definition.
4. No New Eligibility for Interim Status
    RCRA bestows interim status on facilities that were in existence on 
November 19, 1980, or are in existence on the effective date of 
statutory or regulatory changes that render the facility subject to 
RCRA permitting requirements. The original RCRA rules for hazardous 
waste incinerators and BIFs were finalized in 1980 and 1991, 
respectively. Because these rules established the dates on which 
incinerators and BIFs were first subject to RCRA permitting 
requirements, the effective dates of those rules created the only 
opportunity for interim status eligibility. The interim status windows 
that occurred in 1980 and 1991 thus are not modified by this rule. The 
lone exception is that facilities currently burning only nonhazardous 
wastes that become newly listed or identified hazardous waste under 
other future rules would still be able, under existing law, to qualify 
for interim status (Sec. 270.42(g)).
5. What Constitutes Construction Requiring Approval?
    The proposed rule noted that RCRA and CAA both have restrictions 
requiring approval prior to construction, but that each statute defines 
construction differently. We expressed our intent in the NPRM to retain 
the two definitions. In the final rule, we continue to support 
retaining the two definitions. Since most facilities currently possess 
RCRA and CAA permits, these definitions are already being applied 
concurrently with no apparent problems. Consequently, this is the most 
practical and least confusing approach for permittees and regulators.

XII. State Authorization

A. What Is the Authority for Today's Rule?
    Today's rule is being issued under the joint authority of the Clean 
Air Act (CAA), 42 U.S.C. 7401 et seq., and the Resource Conservation 
Recovery Act (RCRA), 42 U.S.C. 6924(o), 6924(q) and 6925. The new MACT 
air emissions standards are located in 40 CFR part 63. Pursuant to 
sections 1006(b) and 3004(a) of RCRA, 42 U.S.C. 6905(b) and 6924(a), 
the MACT program will only be carried out under the CAA delegated 
program. We strongly encourage States to adopt today's MACT standards 
under their CAA statute and to apply for delegation under the CAA if 
they do not have section 112 delegation. State implementation of the 
MACT portions of this rule through its delegated CAA program will 
facilitate coordination between the regulated entity and its State and 
reduce duplicative permitting requirements under the CAA and RCRA.
    In addition to promulgating the MACT standards, today's rule 
modifies the RCRA program in other various respects and States 
authorized for the RCRA base program must revise their programs 
accordingly. For example, this rule revises the test for determining 
whether a facility's waste retains the Bevill exclusion by adding 
dioxins/furans to the list of constituents to be analyzed.
B. How Is the Program Delegated Under the Clean Air Act?
    States can implement and enforce the new MACT standards through 
their delegated 112(l) CAA program and/or by having title V authority. 
A State's title V authority is independent of whether it has been 
delegated section 112(l) of the CAA.
    Section 112(l) of the CAA allows us to approve State rules or 
programs to implement and enforce emission standards and other 
requirements for air pollutants subject to section 112. Under this 
authority, we developed delegation procedures and requirements located 
at 40 CFR part 63, subpart EEE, for National Emission Standards for 
Hazardous Air Pollutants (NESHAPS) under section 112 of the CAA (see 58 
FR 62262, November 26, 1993, as amended, 61 FR 36295, July 10, 1996). 
Similar authority for our approval of state operating permit programs 
under title V of the CAA is located at 40 CFR part 70 (see 57 FR 32250, 
July 21, 1992).
    Submission of rules or programs by States under 40 CFR part 63 
(section 112) is voluntary. Once a State receives approval from us for 
a standard under section 112(l) of the CAA, the State is delegated the 
authority to implement and enforce the part 63 standards under the 
State's rules and regulations (the approved State standard would be 
federally enforceable). States also may apply for a partial 112 
program, such that the State is not required to adopt all rules 
promulgated in 40 CFR part 63. We will implement the portions of the 
112 program not delegated to the State. For example, documents such as 
the NOC will be submitted to the Administrator when due, if the State 
is not approved for the standards in today's rule.
    Under 40 CFR 70.4(a) and section 502(d) of the CAA, States were 
required to submit to the Administrator a proposed part 70 (title V) 
permitting program by November 15, 1993. If a State did not receive our 
approval by November 15, 1995 for its title V program, the title V 
program had to be implemented by us in that State. As of today's rule, 
all States have approved title V programs.\305\ This means that all 
States have the authority to incorporate all MACT standards (changes to 
section 112 of the CAA) into the title V permits as permit conditions, 
and have the authority to enforce all the terms and conditions of the 
title V permits. See 40 CFR 70.4(3)(vii).
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    \305\ Under the CAA, Indian tribes may apply to EPA to be 
treated as States and obtain approval of their own Clean Air Act 
programs. Section 301(d) of the Clean Air Act, 42 U.S.C. 7601(d); 
see also 40 CFR part 49. Tribes may thus become empowered to 
implement the section 112 and title V portions of today's rule is 
areas where they demonstrate jurisdiction and the capacity to do so. 
Currently under RCRA, there is no Tribal authorization for the RCRA 
Subtitle C hazardous waste program and thus EPA generally implements 
the RCRA portions of today's rule in Indian Country.
    EPA has authority to implement the federal operating permits 
program 940 CFR part 71) where a State fails to adequately 
administer and enforce an approved part 70 program, or where a State 
fails to appropriately respond to an EPA objection to a part 70 
permit. Additionally, some sources in U.S. Territories, the Outer 
Continental Shelf, and Indian Country, are subject, or will soon be 
subject, to part 71.
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    The MACT standards are effective upon promulgation of this rule. 
Facilities with a remaining permit term of three or more years will be 
required to submit title V applications to their permitting authorities 
to revise their permits.\306\ States will write the new

[[Page 52992]]

MACT standards into any new, renewed, or revised title V permit and 
enforce all terms and conditions in the title V permit. A State's 
authority to write and enforce title V permits is independent of its 
authority to implement the changes to the MACT standards (changes to 
section 112 of the CAA). Therefore, while both we and the State can 
enforce the federal MACT standards within a title V permit, until the 
State receives approval from us for required changes to section 112 of 
the CAA, we will implement the 112 program.
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    \306\ Title V permits are issued for a period not to exceed five 
years. See 40 CFR 70.4(b)(3)(iii). You will have three years to come 
into compliance with the new MACT standards. If you have fewer than 
three years remaining on your title V permit term, our part 70 
regulations do not require you to reopen and revise your permit to 
incorporate the new MACT standard into the title V permit. See 40 
CFR 70.7(f)(1)(i). However, the CAA does allow State programs to 
require revisions to your permit to incorporate the new MACT 
standard. Therefore, if you have fewer than three years remaining on 
your title V permit, you should consult your state permitting 
program regulations to determine whether a revision to your permit 
is necessary to incorporate the new part 63 MACT standards. If your 
are not required to revise your permit to incorporate the new 
standard, you must still fully comply with today's standard.
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C. How Are States Authorized Under RCRA?
    Under section 3006(g) of RCRA, enacted as part of the Hazardous and 
Solid Waste Amendments (HSWA) of 1984, new requirements imposed by us 
as a result of authorities provided by HSWA take effect in authorized 
States at the same time as they do in unauthorized States--as long as 
the new requirements are more stringent than the requirements a State 
is authorized to implement. We implement these new requirements until 
the State is authorized for them. After receiving authorization, the 
State administers the program in lieu of the Federal government, 
although we retain enforcement authority under sections 3008, 3013, and 
7003 of RCRA.
    Most of the new Federal RCRA requirements in today's final rule are 
being promulgated through the HSWA amendments to RCRA. Regulatory 
changes based on HSWA authorities are considered promulgated through 
HSWA. The following RCRA sections, enacted as part of HSWA, apply to 
today's rule: 3004(o) (changes to the MACT standards), 3004(q) (fuel 
blending), and 3005 (omnibus). As a part of HSWA, these RCRA provisions 
are federally enforceable in an authorized State until the necessary 
changes to a State's authorization are approved by us. See RCRA section 
3006, 42 U.S.C. 6926. The Agency is adding these requirements to Table 
1 in Sec. 271.1(j), which identifies rulemakings that are promulgated 
pursuant to HSWA.
    In contrast, the change to the permit modification table (Appendix 
I to Sec. 270.42) is promulgated through authorities provided to us 
prior to HSWA. Therefore, this change does not become effective until 
States adopt the revision and become authorized for that revision.
    Under RCRA, States that have received authorization to implement 
and enforce RCRA regulatory programs are required to review and, if 
necessary, to modify their programs when we promulgate changes to the 
federal standards that result in the new federal program being more 
stringent or broader in scope than the existing federal standards. This 
is because under section 3009 of RCRA, States are barred from 
implementing requirements that are less stringent than the federal 
program. See also 40 CFR 271.21.
    In four respects, we consider today's final rule to be more 
stringent than current federal RCRA requirements: (1) The added 
definitions for dioxins/furans and TEQ (40 CFR 260.10); (2) the 
requirement that permits for miscellaneous units must include 
appropriate terms and conditions from part 63, subpart EEE standards 
(40 CFR 264.601); (3) the establishment of new standards to control 
particulate matter (40 CFR 266.105(c)); and (4) the addition of dioxin/
furans as listed potential Products of Incomplete Combustion (PIC) (40 
CFR 266.112; Appendix VIII to 40 CFR part 266). Authorized States must 
adopt these requirements as part of their State programs and apply to 
us for approval of their program revisions. The procedures and 
deadlines for State program revisions are set forth in 40 CFR 271.21.
    Section 3009 of RCRA allows States to impose standards that are 
more stringent or more extensive (i.e., broader) in scope than those in 
the Federal program (see also 40 CFR 271.1(i)(1)). Thus, for those 
Federal changes that are less stringent, or reduce the scope of the 
Federal program, States are not required to modify their programs. 
Further, EPA will not implement those provisions promulgated under HSWA 
authority that are not more stringent than the previous federal 
regulations in States that have been authorized for those previous 
federal provisions. EPA will implement these new provisions in States 
that are not authorized to implement the previous federal regulations.
    In two respects, we consider today's rule to be less stringent than 
current federal requirements: (1) The inapplicability of certain 
provisions of RCRA once specified part 63, subpart EEE and other 
requirements have been met (40 CFR 264.340(b)(1); 265.340(b)(1); 
266.100(b)(1), 266.100(d)(1) and (d)(3); 266.100(h); 270.19; 270.22; 
270.62; and 270.66); and (2) the provision for RCRA permit 
modifications to remove inapplicable RCRA conditions (Appendix I to 40 
CFR part 270.42).\307\
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    \307\ States choosing to adopt the other less stringent changes 
to RCRA in today's rule also should adopt the change to 40 CFR 
270.42. The change to 40 CFR 270.42 provides the RCRA permit 
modification procedure to eliminate inapplicable RCRA requirements 
once specified part 63, subpart EEE and other requirements have been 
met.
---------------------------------------------------------------------------

    The rest of the requirements in today's rule, in our view, are 
neither more nor less stringent than current regulatory requirements. 
They are either reiterations or clarifications of our existing 
regulations or policies (40 CFR 264.340(b)(2), 265.340(b)(2), 
266.100(b)(2), and 266.101).
    Although States must adopt only those requirements that are more 
stringent, in the spirit of RCRA section 1006(b), which directs us to 
avoid duplicative RCRA and CAA requirements, we strongly urge States to 
adopt all aspects of today's final rule (including the clarifying as 
well as less stringent sections). The adoption of all portions of 
today's final rule by state agencies will ensure clear, consistent 
requirements for owners, operators, affected sources, State regulators, 
and the public. Pursuant to today's rule, the permitting requirements 
will be implemented solely through the CAA title V program. If a RCRA 
permitted facility is required to use RCRA risk-based air emissions 
standards in addition to the CAA designated technology based standards, 
we will exercise our omnibus authority in section 3005 of RCRA to 
modify the facility's RCRA permit.\308\ Therefore, we believe that the 
standards promulgated today properly implement the goals of sections 
3004(o) and (q) of RCRA to ensure the safe and proper management of the 
affected combustion units and the goal of section 1006(b) of RCRA to 
avoid duplicative and potentially confusing permitting requirements 
under two different environmental statutes (RCRA and CAA). For these 
reasons, we encourage States to adopt these

[[Page 52993]]

regulations as quickly as their legislative and regulatory processes 
will allow.
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    \308\ If a State has a provision in its State air statute or 
regulation that is equivalent to the RCRA omnibus authority (RCRA 
section 3005(c)), we expect that the State will be able to use its 
air authority in pace of its RCRA omnibus authority.
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Part Six: Miscellaneous Provisions and Issues

I. Does the Waiver of the Particulate Matter Standard or the 
Destruction and Removal Efficiency Standard Under the Low Risk Waste 
Exemption of the BIF Rule Apply?

    Section 266.109 of the current BIF regulation provides a 
conditional exemption from the destruction and removal efficiency 
standard and the particulate matter standard for low risk wastes. We 
proposed to restrict eligibility for the waiver of the particulate 
matter standard to BIFs other than cement and lightweight aggregate 
kilns because the waiver could supersede the MACT requirements for the 
particulate matter standards. We had the same concern for the 
destruction and removal efficiency requirements. See 61 FR at 17470. 
After reconsidering the issue, we are clarifying that today's MACT 
requirements are separately applicable and enforceable and that no 
action is needed to ensure that a BIF waiver does not supersede the 
MACT requirements. See the discussions in Part Five of today's preamble 
regarding integration of the MACT and RCRA standards.

II. What Is the Status of the ``Low Risk Waste'' Exemption?

    Section 264.340(b) and (c) exempts certain incinerators from the 
RCRA emission standards if the hazardous waste burned contains (or 
could reasonably be expected to contain) insignificant concentrations 
of Appendix VIII, part 261, hazardous constituents. We proposed that 
this ``low risk waste'' provision no longer be applicable incinerators 
on the MACT compliance date because a risk-based exemption from 
technology-based MACT standards seemed inappropriate. See 61 FR at 
17470. After reconsidering the issue, we have determined that no 
specific action is necessary because the MACT standards are separately 
applicable and enforceable standards. See the discussion in Part Five 
of today's preamble regarding integration of the MACT and RCRA 
standards.

III. What Concerns Have Been Considered for Shakedown?

    In the proposal, we expressed concern that some new units do not 
effectively use their allotted 720-hour pre-trial burn shakedown period 
or appropriate extensions to correct operational problems. This can 
potentially lead to trial burn failures and emission exceedances, which 
pose unnecessary risks to human health and the environment. Therefore, 
we proposed three shakedown options to enhance regulatory control over 
trial burn testing:
    (1) Prior to scheduling trial burns, we would require facilities to 
provide the Director a minimum showing of operational readiness.
    (2) We would require notification of operational readiness prior 
to, and following, the shakedown period.
    (3) We would provide guidance on how to effectively prepare for a 
trial burn. These options were proposed for inclusion under both the 
CAA and RCRA regulations, and comments were requested regarding their 
usefulness.
    A few commenters preferred Option 3 because it would be useful in 
determining how to effectively prepare for a trial burn. Regarding 
Options 1 and 2, two commenters felt the cost, time, and resources 
required for a trial burn already provide adequate financial incentive 
to prepare, plan, and conduct trial burns efficiently. Two commenters 
felt that Option 3 provided the potential for inequities in 
implementation of the guidance by the permit writer. In general, most 
commenters agreed that additional regulatory requirements are not 
necessary.
    In light of the comments, we decided not to adopt any of the 
proposed options. We acknowledge that it is in the facility's best 
interest to conduct a successful trial burn that most facilities will 
properly utilize their shakedown period. However, during the transition 
period from RCRA to MACT compliance, we strongly encourage facilities 
to properly use their shakedown period to correct operational problems 
that pose unnecessary risks to human health and the environment.
    Therefore, with the exception of risk burns, we are pursuing the 
deferral of RCRA trial burns to the MACT performance test requirements. 
A source remains subject to RCRA trial burns during the transition 
period to MACT compliance. For facilities where unique considerations 
make a SSRA necessary, risk-based permit conditions may result. In such 
cases, there likely would need to be conditions for all phases of 
operation in the RCRA permit. Thus, start-up and shakedown would still 
be an issue for some RCRA combustor facilities given that they would 
have to be in compliance with the unique RCRA emission standards even 
during startup and shakedown (unless the permit conditions specify 
otherwise).

IV. What Are the Management Requirements Prior to Burning?

    Today, we are finalizing the proposal to revise 40 CFR 266.101 
(``Management prior to burning'') to clarify that fuel blending 
activities are regulated under RCRA. See 61 FR at 17474 (April 19, 
1996). As described in detail in the proposal, this is already implicit 
(and for some units, explicit) in existing rules. Therefore, today's 
rule is more an interpretive clarification. See 52 FR 11820 (April 13, 
1987). By incorporating the term ``treatment'' into the regulation, we 
are clarifying that fuel blending activities that are conducted in 
units other than 90-day tanks or containers also are subject to 
regulation.
    We received two comments expressing concern that this would subject 
all fuel blending-related equipment permitting, without allowing for 
case-by-case determinations. For example, these commenters believe that 
some pre-processing activities conducted by blenders (shredding, drum 
crushing, and other physical handling) do not meet the definition of 
treatment and should not be subject to permitting standards. However, 
we feel that these activities meet the existing definition of 
treatment. They are ``processe(s) . . . designed to change the physical 
. . . composition of . . . hazardous waste so as to . . . render such 
waste amenable for recovery'' via combustion. See 40 CFR 260.10 
(definition of ``treatment'').
    Moreover, these pre-processing activities should be subject to 
permitting requirements. Controls on these activities are necessary to 
protect against releases of hazardous constituents to the environment 
due to the nature of those operations (e.g., crushing or shredding of 
drums containing hazardous wastes, grinding of waste materials, etc.). 
See Shell Oil v. EPA, 950 F. 2d 741, 753-56 (D.C. Cir. 1991), which 
broadly construes the definition of treatment to assure that the RCRA 
goal of cradle-to-grave management of hazardous wastes is satisfied and 
that specific types of units remain subject to subtitle C regulation. 
For units that do not already meet the definition of a specific unit, 
subpart X is available to provide the appropriate standards.

V. Are There Any Conforming Changes to Subpart X?

    In today's rule, we are making a conforming change to part 264 
subpart X (Sec. 264.601) to make reference to part 63 subpart EEE.
    Hazardous waste treatment, storage, and disposal facilities that 
are not

[[Page 52994]]

classified under other categories (e.g., tank systems, surface 
impoundments, waste piles, incinerators, etc.) are classified as 
miscellaneous units and regulated under part 264 subpart X. However, 
due to the varying types and designs of miscellaneous units, subpart X 
does not include specific performance standards. Instead, subpart X 
makes reference to requirements in other sections of the regulations. 
Section 264.601 of subpart X states that ``Permit terms and provisions 
shall include those requirements of subparts I through O and subparts 
AA through CC of this part, part 270, and part 146 that are appropriate 
for the miscellaneous unit being permitted .'' This statement directs 
the permitting agency to look at the requirements (e.g., performance 
standards, operating parameters, monitoring requirements, etc.) from 
other sections in the regulations when developing appropriate permit 
conditions for miscellaneous units.
    In the past, permitting authorities have often looked to the part 
264 subpart O regulations for incinerators to develop the appropriate 
permit conditions for units such as thermal desorbers and carbon 
regeneration units. Since today's rule upgrades the air emission 
standards for certain source categories, these new standards also 
should be considered when determining the appropriate requirements for 
miscellaneous units, most notably those engaged in any type of thermal 
operation. Therefore, the language in Sec. 264.601 of subpart X is 
being modified to incorporate a reference to part 63 subpart EEE.

VI. What Are the Requirements for Bevill Residues?

A. Dioxin Testing of Bevill Residues
    In the proposal, we proposed to add polychlorinated dibenzo-p-
dioxin and polychlorinated dibenzo-furan compounds to appendix VIII of 
part 266. Appendix VIII lists those compounds that may be generated as 
products of incomplete combustion and that must be included in testing 
of Bevill residues conducted pursuant to 40 CFR 266.112. Products of 
incomplete combustion can be unburned organic compounds that were 
originally present in the waste, thermal decomposition products 
resulting from organic constituents in the waste, or compounds 
synthesized during or immediately after combustion. We noted in the 
proposal that there is a considerable body of evidence to show that 
dioxin and furan compounds can be formed in the post-combustion regions 
of hazardous waste burning boilers, industrial furnaces, and 
incinerators, especially at temperatures between 250-450 deg.C.\309\ 
\310\ Collected particulate matter in the post-combustion regions of 
furnaces can provide sites for adsorption of precursors, formation of 
dioxins and furans by surface chlorination of precursors, catalytic 
production of chlorine for subsequent chlorination of dioxin and furan 
precursors, and de novo synthesis of dioxins and furans. This same 
particulate matter may be subsequently managed as excluded Bevill 
residue.
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    \309\ USEPA, ``Estimating Exposure to Dioxin-Like Compounds'', 
EPA/600/6-88/005Ca, June 1994.
    \310\ USEPA, ``Combustion Emissions Technical Resource Document 
(CETRED)''. EPA/530/R-94/014, May 1994.
---------------------------------------------------------------------------

    No evidence was provided by commenters to show that dioxins and 
furans cannot be formed in cooler, post-combustion regions of furnaces 
(e.g., ductwork, boiler tubes, heat exchange surfaces, and air 
pollution control devices). A few commenters referenced the total 
number of nondetects for all of the compounds in the cement kiln dust 
database. However, the relevance of this information specifically to 
dioxins and furans was unclear. Dioxins and furans have repeatedly been 
detected in cement kiln dust, as well as other Bevill residues.\311\ 
\312\
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    \311\ USEPA, ``Report to Congress on Cement Kiln Dust'', EPA/
530/R-94/001, December 1993.
    \312\ USEPA, ``Dioxins/Furans, Metals, Chlorine, Hydrochloric 
acid, and Related Testing at a Hazardous Waste-Burning Light-Weight 
Aggregate Kiln'', June 1997 Draft Report.
---------------------------------------------------------------------------

    The majority of commenters were concerned about implementation 
issues. Many felt that the addition of dioxins and furans to part 266 
appendix VIII, in conjunction with the proposed requirement for daily 
sampling and analysis of Bevill residues, would make Bevill 
demonstrations prohibitively expensive. They also noted that the 
turnaround time for daily dioxin and furan analyses would delay 
compliance demonstrations and result in shortages in storage capacity. 
One commenter felt that daily sampling for dioxins and furans is not 
warranted because cement kiln dust at their site has already been shown 
to meet the proposed Bevill exclusion criteria for dioxins and furans. 
None of these arguments directly address our basic premise that dioxin 
and furan compounds can be generated in combustion systems, are of 
concern to the protection of human health and the environment, and, as 
such, should be included in part 266 appendix VIII. Rather, these 
comments pertain to issues that are more readily and appropriately 
resolved within the context of site-specific Bevill testing plans.
    The proposed daily residue test frequency, which was cited most 
often as an impediment in conjunction with dioxin and furan analysis, 
is not being promulgated as part of today's rule. The rule will leave 
maximum flexibility for development of appropriate dioxin and furan 
analysis frequencies considering site-specific factors. Most facilities 
should be able to substantially limit the number of dioxin and furan 
analyses after an initial sampling effort. Most residue test plans rely 
on the concentration-based comparisons to F039 nonwastewater levels (40 
CFR 266.112(b)(2)) in combination with a phased testing approach. Under 
the phased approach, test frequency can be substantially reduced for 
those constituents where initial sampling efforts reveal that 
concentrations are well below the F039 levels. Of the facilities where 
residue testing for dioxins and furans has been performed, we are aware 
of only two facilities where dioxins and furans have exceeded the F039 
levels. Thus, the burden of higher analytical costs is expected to be 
appropriately limited to those few sites with significant dioxin and 
furan residue concentrations.
    Several commenters pointed out that some Bevill residues (e.g., 
slag from primary smelters) are generated prior to the post-combustion 
regions typically associated with dioxin and furan formation. Indeed, 
the preamble discussion in the proposal focused exclusively on post-
combustion residues and did not address Bevill-exempt primary smelter 
slags. We currently do not have analytical data on dioxins and furans 
in smelter slag. However, our current information on dioxin and furan 
formation mechanisms suggests that it would be highly unlikely to 
expect significant dioxins and furans in smelter slag. Therefore, we 
agree that dioxin and furan analyses should be limited to those 
residues where there is a reasonable expectation that dioxins and 
furans could be present (e.g., post-combustion residues).
    Finally, two commenters disagreed with our assertion that dioxins 
and furans have been shown, in a national comparison, to be higher in 
residues from hazardous waste burning cement kilns than from other 
cement kilns. Although this information was included in the proposal as 
background, it is not necessary to reconcile various interpretations 
regarding national trends for today's rule. The 40 CFR 266.112 
provisions are site-specific, and 40 CFR 266.112(b)(1) provides ample 
opportunity for you to demonstrate, on a site-specific basis as 
necessary, that waste-derived residues are not

[[Page 52995]]

significantly different from normal residues.
    After considering all of the comments on the proposal, we are 
adding dioxins and furans to part 266 appendix VIII in today's rule. A 
notation has been included to clarify that dioxin and furan analyses 
are required only for post-combustion residues. Commenters provided no 
compelling information to challenge the classification of dioxins and 
furans as products of incomplete combustion which can be formed in 
post-combustion regions of combustion systems, and the presence of 
dioxin and furan compounds in several post-combustion Bevill residues 
is clearly documented. Also, the increased use of carbon injection 
technology to achieve dioxin and furan stack emissions reductions could 
increase dioxin and furan contamination of Bevill residues in the 
future. The addition of dioxins and furans to part 266 appendix VIII is 
not expected to unduly burden the regulated community because 
facilities with dioxins and furans well below exclusion levels should 
be able to justify a minimum test frequency.
    Dioxins and furans will be listed in part 266 appendix VIII simply 
as ``Polychlorinated dibenzo-p-dioxins'' and ``Polychlorinated dibenzo-
furans''. However, the specific form of dioxins and furans that must be 
determined analytically will depend on the portion of the two-part test 
that is being implemented. If you are performing a comparison with 
normal residues pursuant to 40 CFR 266.112(b)(1), specific congeners 
and homologues must be measured and converted to TEQ values using the 
procedure provided in part 266, appendix IX, section 4.0. We received 
no comments regarding this portion of the proposal. If you are 
utilizing the concentration-based comparison to the F039 nonwastewater 
levels in 40 CFR 268.43 as outlined in 40 CFR 266.112(b)(2), then only 
the tetra-, penta-, and hexa-homologues need to be measured (these are 
the only homologues with established F039 concentration limits). One 
commenter seemed uncertain as to whether the tetra-, penta-, and hexa-
homologue concentrations should be converted to TEQ values. We have 
revised the regulatory language to clarify that total concentrations 
for each homologue, not TEQs, should be used for the F039 comparisons. 
Another commenter objected to the use of F039 levels for the health-
based comparison, noting that the F039 concentrations are technology-
based levels. Our rationale for relying on the F039 concentrations has 
been explained previously (see 58 FR at 59598, November 9, 1993) and is 
not being revisited in today's rule.
B. Applicability of Part 266 Appendix VIII Products of Incomplete 
Combustion List
    In the proposal, we noted the confusion regarding whether every 
constituent listed on the part 266 appendix VIII list must be included 
in residue testing at every facility. We proposed to clarify that the 
part 266 appendix VIII list is applicable in its entirety to every 
facility.
    The only comments received on this issue were objections to our 
characterization of this change as a clarification. The commenters felt 
this was a substantive change that should not be enforced prior to the 
effective date of any final rule establishing the revision as law. The 
Agency is proceeding in today's rule to make the part 266 appendix VIII 
list applicable in its entirety to every facility by changing the title 
of the appendix from ``Potential PICs for Determination of Exclusion of 
Waste-Derived Residues'' to ``Organic Compounds for Which Residues Must 
Be Analyzed.'' This change is considered a revision to the part 266 
regulations effective 30 days after the date of publication of today's 
rule. We will not seek to retroactively enforce this provision.

VII. Have There Been Any Changes in Reporting Requirements for 
Secondary Lead Smelters?

    We proposed that secondary lead smelters subject to MACT standards 
for the secondary lead source category not be subject to RCRA air 
emission standards. 61 FR at 17474 (April 19, 1996). This exemption 
would apply only if a secondary lead smelter processed the type of feed 
material we evaluated in promulgating the secondary lead MACT 
standards, namely, lead-bearing hazardous wastes containing less than 
500 ppm toxic nonmetals and/or hazardous wastes listed in appendix XI 
to 40 CFR part 266. Id. at 14475. Secondary lead smelters are presently 
not subject to RCRA air emission standards under these circumstances. 
See existing Sec. 266.100 (c)(1) and (c)(3). However, they are subject 
to certain notification and recordkeeping requirements found in 
Sec. 266.100 (c)(1)(I) and (c) (3) and on-going sampling and analysis 
requirements in Sec. 266.100 (c)(1)(ii) and Sec. 266.100 (c)(3)(i)(D). 
The practical effect of the proposal was to continue to relieve 
secondary lead smelters of these administrative requirements.
    The proposal was supported by the public commenters. The reason for 
the proposal remains. That is, now that secondary lead smelters are 
complying with MACT standards for their source category, it is not 
necessary for them to be regulated under RCRA also for their air 
emissions. 60 FR 29750 (June 23, 1995). For the same reason, it is 
unnecessary to have the same level of recordkeeping and other 
administrative oversight as when these units were exempt from RCRA air 
emission requirements but not yet complying with CAA standards for 
hazardous air pollutants. 61 FR at 14474. Consequently, we are 
finalizing this portion of the proposal.
    Today's rule takes the form of an amendment to the RCRA BIF rule 
(new Sec. 266.100 (h)) and indicates that secondary lead smelters are 
exempt from all provisions of the BIF rule except for Sec. 266.101, 
which contains the restrictions on types of hazardous waste which may 
be burned, as described in the first paragraph above. As proposed, a 
secondary lead smelter must provide a one-time notice to the Regional 
Administrator or State Director identifying each hazardous waste burned 
and stating that the facility claims an exemption from other 
requirements in the BIF rules. Those secondary lead smelters which have 
already notified pursuant to existing regulatory provisions (namely 
Sec. 266.100 (c) (1) (i) or Sec. 266.100 (c) (3) (i) (D)) would not 
have to renotify.

VIII. What Are the Operator Training and Certification Requirements?

    Section 129 of the CAA requires us to develop and promulgate a 
program for training and certification of operators of facilities that 
burn municipal and medical wastes. We accordingly promulgated operator 
training and certification requirements for the operators of municipal 
waste combustors (60 FR 65424 (December 19, 1995)) and medical waste 
incinerators (62 FR 48348 (September 15, 1997)). At proposal, we 
considered similar requirements for hazardous waste combustor operators 
also and requested comments on whether: (1) Operator certification 
requirements are necessary for hazardous waste combustors, and (2) the 
American Society of Mechanical Engineers (ASME) standards (or an 
equivalent state certification program) are appropriate and sufficient. 
We note that ASME has established a Standard for the Qualification and 
Certification of Hazardous Waste Incinerator Operators in collaboration 
with the American National Standards Institute (ASME Standard Number 
QHO-1-1994) and has been providing certifications since 1996.

[[Page 52996]]

    Commenters differed widely on two key issues: (1) Whether such a 
training program should be voluntary, mandatory, or even necessary, 
considering that RCRA already requires some site-specific training 
program (40 CFR 264.16); and (2) whether the certifying agency should 
be an independent body like ASME versus an industry organization like 
the Cement Kiln Recycling Coalition. Most commenters favored the 
establishment of a mandatory operator certification program by an 
independent organization that develops consensus standards (e.g., ASME, 
American Society for Testing and Materials, or American National 
Standards Institute) in order to preserve the integrity of 
certification. We agree and note that ASME has already done commendable 
work in developing certification programs for operators of municipal 
waste combustors, medical waste incinerators, high capacity fossil-fuel 
fired plants, and hazardous waste incinerators. Each combustor program 
includes defined criteria for certification, including operator 
qualifications, recommended training, examination content, minimum 
passing grades, and due process. These programs are incorporated (at 
least in part) into EPA's combustion regulations to satisfy the CAA 
section 129 mandate, and we are extending similar requirements in 
today's rule to all hazardous waste combustor operators also. We find 
that the concerns about good operator training and certification that 
underlie the section 129 requirement for municipal waste combustors and 
medical waste incinerators apply as well to those persons charged with 
the responsibility for safe handling and burning of hazardous waste.
    Some kiln operators and the Cement Kiln Recycling Coalition have 
commented that cement and lightweight aggregate kilns are much larger 
and more diverse facilities than most hazardous waste incinerators, 
that these kilns operate with employee unions that object to additional 
outside certification when site-specific training programs are already 
in place, and that the ASME certification programs are not pertinent or 
applicable to them. We recognize that there are some differences in the 
operation of incinerators and cement and lightweight aggregate kilns. 
However, these differences do not suggest that operator training and 
certification should be abandoned. Rather, they serve to emphasize the 
importance of having a rigorous operator training and certification 
program in place and having it subject to regulatory agency scrutiny. 
In that regard, we are aware of the Cement Kiln Recycling Coalition's 
efforts to develop a suitable industry-wide training and certification 
program for the kilns. However, the Cement Kiln Recycling Coalition's 
efforts to date have not resulted in a final industry-wide set of 
standards that can be relied upon in today's rule, and we note that the 
current general facility training programs under Sec. 264.16 do not 
fully cover the areas that would need to be addressed at facilities 
burning hazardous waste. For example, Sec. 264.16 neither identifies 
important areas of training with respect to daily operations (such as 
hazardous waste and residues handling operations, air pollution control 
device operations, troubleshooting, normal start-up and shut-down 
procedures, continuous emissions monitoring system operation and 
maintenance etc.) nor discriminates among the different categories of 
operators. Also, Sec. 264.16 does not specify any operator 
certification nor minimum standards for certification, which are needed 
to ensure the initial and continual competence of the hazardous waste 
combustor facility operators.
    We expect that kiln specific programs will be developed in the near 
future after complete analysis for consistency, reliability and 
conformance with principles of good operating and operator practices 
(including training and certification). Today's rule therefore 
specifies that each hazardous waste combustor facility must develop an 
operator training and certification program. In the case of cement and 
lightweight aggregate kilns, the facility must submit its program to 
the Agency for approval. The submittal will be evaluated for 
completeness, reliability and conformance with appropriate principles 
of good operator and operating practices (including training and 
certification). If a state-approved certification program becomes 
available, the facility's program must conform to that state program. 
These are to ensure that sufficient specifics are included in each 
facility program. In the case of hazardous waste incinerators, the 
facility's program must conform to either a state-approved 
certification program or, if none exists, to the ASME certification 
program (Standard No. QHO-1-1994). Again, this is to ensure that 
sufficient specifics are contained in a facility program.

IX. Why Did the Agency Redesignate Existing Regulations Pertaining to 
the Notification of Intent To Comply and Extension of the Compliance 
Date?

    In today's final rule, we redesignate existing regulations 
pertaining to the Notification of Intent to Comply with subpart EEE and 
extensions of the compliance date to install pollution prevention or 
waste minimization controls to meld them into the new provisions of the 
subpart. This ensures that similar topics (e.g., notifications, 
compliance requirements) are grouped together in the rule. We also 
revise those existing regulations to: (1) Convert the regulatory 
language to plain language consistent with the new provisions; (2) 
include references to the new provisions; and (3) include references to 
the actual effective date of the rule.
    We promulgated these regulations as Part 1 of revised standards for 
hazardous waste combustors. See 63 FR 33782 (June 19, 1998). We are 
promulgating part 2 today, which comprises the emission standards and 
compliance requirements. Today's revisions to the existing standards 
does not constitute a repromulgation and does not reopen the comment 
period for those standards.
    We are redesignating the existing regulations as indicated in the 
following table:

----------------------------------------------------------------------------------------------------------------
          Existing regulation                         Topic                      Predesignated regulation
----------------------------------------------------------------------------------------------------------------
Sec.  63.1211(a) and (b)...............  Notification requirements for   Sec.  63.1210(b) and (c)
                                          the notification of intent to
                                          comply.
Sec.  63.1211(c).......................  Requirements for sources that   Sec.  63.1206(a)(2)
                                          do not intend to comply.
Sec.  63.1212..........................  Progress report requirements    Sec.  63.1211(b)
                                          for the notification of
                                          intent to comply.
Sec.  63.1213..........................  Certification that must         Sec.  63.1212(a)
                                          accompany the notice of
                                          intent to comply.
Sec.  63.1214..........................  Extension of the compliance     Sec.  63.1206(a)(1)
                                          date.
Sec.  63.1215..........................  Requirements for sources that   Sec.  63.1212(b)
                                          become affected sources after
                                          the effective date of the
                                          emission standards.

[[Page 52997]]

 
Sec.  63.1216..........................  Extension of the compliance     Sec.  63.1213
                                          date to install pollution
                                          prevention or waste
                                          minimization controls.
----------------------------------------------------------------------------------------------------------------

Part Seven: National Assessment of Exposures and Risks

    We received many public comments on the risk assessment for the 
proposed rule.313 In addition, the risk assessment was peer 
reviewed in accordance with EPA guidelines. Many of the commenters 
commented on similar topics. These topics included the 
representativeness of the HWC facilities modeled, the estimation of 
facility emissions, the exposure scenarios evaluated, and the 
assessment of risks from mercury. As of result of these comments, we 
made significant changes in the risk assessment for the final rule. 
Also, new information became available after proposal on food intake 
rates for home-produced foods and methods for assessing exposures to 
mercury. In addition, EPA issued guidance for use of probabilistic 
techniques in risk assessments and a policy for evaluating risks to 
children. These were also considered in making revisions to the risk 
assessment. A complete discussion of the risk assessment for today's 
rule may be found in the background document.314
---------------------------------------------------------------------------

    \313\ ``Risk Assessment Support to the Development of Technical 
Standards for Emissions from Combustion Units Burning Hazardous 
Wastes: Background Information Document,'' February, 1996.
    \314\ See the background document, ``Human Health and Ecological 
Risk Assessment Support to the Development of Technical Standards 
for Emissions from Combustion Units Burning Hazardous Wastes: 
Background Document--Final Report,'' July, 1999.
---------------------------------------------------------------------------

I. What Changes Were Made to the Risk Methodology?

A. How Were Facilities Selected for Analysis?
    The representativeness of the example facilities used in the risk 
assessment at proposal was widely questioned by commenters. We analyzed 
eleven example facilities for the proposed rule: two commercial 
incinerators, two on-site incinerators, two lightweight aggregate 
kilns, and five cement kilns.315 While these facilities 
represented a geographically diverse set of facilities in each source 
category, it was not possible to demonstrate in any formal way that the 
facilities were representative of the universe of facilities covered by 
the rule.
---------------------------------------------------------------------------

    \315\ See 61 FR 17370 and ``Risk Assessment Support to the 
Development of Technical Standards for Emissions from Combustion 
Units Burning Hazardous Wastes: Background Information Document'' 
(February, 1996).
---------------------------------------------------------------------------

    Because of this difficulty, we concluded that the most efficient 
approach for assuring the representativeness of the facilities analyzed 
was to select a stratified random sample. The number of strata was 
determined by the number of categories and subcategories of sources for 
which risk information was desired. The final sample of facilities 
chosen for analysis includes 66 randomly selected facilities and 10 of 
the 11 facilities selected at proposal for a total sample of 76 
facilities out of a universe of 165 facilities within the contiguous 
United States.316 The sample sizes are as follows:
---------------------------------------------------------------------------

    \316\ A large on-site incinerator analyzed at proposal that is 
undergoing RCRA closure was excluded from the analysis.

                          Hazardous Waste Combustion Facility Stratum and Sample Sizes
----------------------------------------------------------------------------------------------------------------
                                                                                                     High end
  Combustion facility category     Stratum size    Random sample    NPRM sample    Final sample      sampling
                                                       size            size            size         probability
--------------------------------------------------------------------------------------------------------\1\-----
Cement Kilns....................              18              10               5              15              98
Lightweight Aggregate Kilns.....               5               3               2               5             100
Commercial Incinerators:
    Including Waste Heat Boilers              20              11               2              13              97
    Excluding Waste Heat Boilers              12               7               2               9              95
Large On-Site Incinerators:
    Including Waste Heat Boilers              43              17               1              18              94
    Excluding Waste Heat Boilers              36              15               0              15              90
Small On-Site Incinerators:
    Including Waste Heat Boilers              79              25               0              25              96
    Excluding Waste Heat Boilers              65              16               0              16              88
Incinerators With Waste Heat                  29              15               1              16             92
 Boilers........................
----------------------------------------------------------------------------------------------------------------
\1\ Probability that a facility that lies in the upper 10% of the distribution of risk will be sampled.

For the randomly selected facilities, sample sizes within a given 
category were chosen such that the probability of sampling a facility 
in the upper ten percent of the distribution of risk would be 90 
percent or greater. The probabilities actually achieved range from 88 
to 100 percent depending on the size of the original, non-randomly 
chosen sample and changes in the sampling frame that occurred during 
the random sampling process.317
---------------------------------------------------------------------------

    \317\ Changes in the sampling frame occurred as a result of 
facilities that were missing from the original sampling frame were 
misclassified, or were no longer burning hazardous waste and had 
begun RCRA closure.
---------------------------------------------------------------------------

    We did not target area sources specifically for sampling because 
the statutory definition of major sources versus area sources is based 
on facility-wide emissions of hazardous air pollutants and such 
information was not available at the time the sampling was performed. 
Therefore, it was not possible to determine the sampling frame. We 
expect that on-site incinerators, both large and small, at large 
industrial facilities are major sources rather than area sources. 
Because area sources are of interest, we made risk inferences based on 
those area source incinerators that could be identified and had 
otherwise been

[[Page 52998]]

sampled.318 For cement kilns, all area sources were sampled 
and used for making such inferences.
---------------------------------------------------------------------------

    \318\ Area source incinerators that were identified included 
commercial incinerators and on-site incinerators at U.S. Department 
of Defense installations.
---------------------------------------------------------------------------

B. How Were Facility Emissions Estimated?
    At proposal, we estimated baseline emissions (reflecting current 
conditions) for the example facilities from the distribution of stack 
gas concentrations for the corresponding category of sources. Both 
central tendency and high end emissions estimates were made based on 
the 50th and 90th percentiles of the stack gas concentration 
distributions. For the purpose of evaluating risks associated with the 
proposal, we assumed that facilities emitted at the design level 
determined to be necessary to meet the standard, even if this meant an 
increase in emissions over baseline. Many commenters thought that using 
percentiles to estimate emissions was inappropriate and that site-
specific emissions should be used instead. Commenters also thought that 
it was incorrect to project an increase in risk with the proposed 
standards (which occurred as a result of allowing emissions to increase 
over baseline). We agree with these comments. For the final rule, we 
estimated emissions based on site-specific stack gas emission 
concentrations and flow rates. Site-specific stack gas concentration 
data were used where emissions measurements were available; otherwise, 
stack gas concentrations were imputed. For today's rule, we assumed 
emissions would remain unchanged from baseline in instances where a 
facility's emissions are already below the design level (which is taken 
as 70 percent of the MACT standard).319 In instances where a 
facility's emissions exceed the design level, we determined the 
percentage reduction in emissions required to meet the design level. We 
then applied this reduction to each chemical constituent to which the 
standard applies.
---------------------------------------------------------------------------

    \319\ This is also consistent with the assumption made in the 
cost and economic analysis that facilities that are currently 
emitting below the design level will not need to retrofit using new 
control technology.
---------------------------------------------------------------------------

    The imputation approach we used in instances where measured data 
were not available involves the random selection of emissions 
concentrations from a pool of emissions concentrations for other 
facilities and test conditions that are believed to be reasonably 
representative of the facility in question. For groups of interrelated 
constituents (e.g., different dioxin congeners or mercury species), 
imputation was carried out for the group of interrelated constituents 
taken together rather than each individual constituent separately. We 
used the random imputation approach to preserve the variability in 
emissions exhibited by the pooled data. Another commonly used approach 
for estimating emissions, emissions factors, generally represents 
average conditions and does not reflect the variability in emissions 
across facilities in a given source category. Because the objective of 
the risk assessment is to characterize the distribution of risks across 
a given source category, we deemed the use of average emissions to be 
inappropriate except where only very limited data are available (i.e., 
for cobalt, copper, and manganese). Although the random imputation 
approach may significantly over or under estimate emissions for a given 
facility (a problem also inherent in emission factors), we expect that 
the distributions of risk across a given source category are better 
characterized using random imputation than with an emissions factor 
approach or any other approach that does not account for the variation 
in emissions from one facility to the next.
    Emissions estimates were made for all chemical constituents covered 
by the rule for which sufficient data were available, including all 
2,3,7,8-chlorine substituted dibenzo(p)dioxins and dibenzofurans, 
elemental mercury (Hg0), divalent mercury (Hg+2), 
lead, cadmium, arsenic, beryllium, trivalent chromium 
(Cr+3), hexavalent chromium (Cr+6), chlorine, and 
hydrogen chloride. In addition, emissions estimates were made for 
particulate matter (PM10 and PM2.5) and nine 
other metals, three of which (cobalt, copper, and manganese) were not 
assessed at proposal but were included in the risk assessment for the 
final rule. Chemical-specific emissions estimates could not be made for 
organic constituents other than dioxins and furans (e.g., various 
products of incomplete combustion) due to the lack of sufficient 
emission measurements. We assessed the risks from all constituents for 
which chemical-specific emissions estimates could be made, as well as 
from particulate matter. A complete discussion of the emissions 
estimates used in the risk assessment may be found in the technical 
support documents for today's rule.320
---------------------------------------------------------------------------

    \320\ See ``Final technical Support Document for HWC MACT 
Standards, Volume V: Emission Estimates and Engineering Costs.'' 
July, 1999.
---------------------------------------------------------------------------

C. What Receptor Populations Were Evaluated?
    The risk assessment at proposal examined risks to individuals 
engaged in subsistence activities such as farming and fishing. Some 
commenters viewed these types of activities as unlikely to occur and 
questioned whether these types of exposures are representative of 
actual exposures and risk. Other commenters thought the exposure 
pathways included in the analysis did not fully reflect potential 
exposures to individuals living a true subsistence lifestyle. We share 
the concerns raised by commenters and have refocused the assessment on 
non-subsistence receptor populations such as commercial farmers, 
recreational anglers, and non-farm residents whose numbers and 
locations can be estimated from available census data. At the same 
time, we retained the subsistence scenarios and revised them to be more 
reflective of a subsistence lifestyle. Although it is not known 
precisely how many individuals are engaged in subsistence activities or 
exactly where those activities take place, subsistence does occur in 
some segments of the U.S. population, and we believe it is important to 
evaluate the associated risks.
D. How Were Exposure Factors Determined?
    Since the risk assessment at proposal, we have developed new 
information on factors that are used to estimate exposures. We obtained 
data collected from previously published studies and used the data to 
derive exposure factor information, including information for 
children.321 In particular, we reanalyzed data collected by 
USDA to estimate consumption of home-produced foods, such as meat, 
milk, poultry, fish, and eggs. Over half of farm households report 
consuming home-produced meats, including nearly 40 percent that report 
consumption of home-produced beef. In the Northeast, nearly 40 percent 
of farm households report consuming home-produced dairy products, and, 
in the Midwest, nearly 20 percent do. The percentage is lower 
elsewhere, averaging about 13 percent nationally. Presumably most of 
these households are associated with dairy farms. Most farm households 
that consume home-produced foods are engaged in farming as an 
occupation rather than a means of subsistence.
---------------------------------------------------------------------------

    \321\  EPA published the new exposure factor information in the 
``Exposure Factors Handbook,'' EPA/600/P-95/002Fb, August, 1997.
---------------------------------------------------------------------------

    The data indicate that individual consumption of home-produced 
foods is

[[Page 52999]]

higher than consumption of the same foods in the general populace. We 
have used the information on home-produced foods to estimate the 
exposures to farm households and to households engaged in subsistence 
farming. Only the primary food commodity produced on the farm was 
assumed to be consumed by farm households. In contrast, a wide variety 
of foods was assumed to be produced and consumed by households engaged 
in subsistence farming.
E. How Were Risks from Mercury Evaluated?
    Commenters viewed the absence of a quantitative assessment of risks 
from mercury as a significant failing at proposal. However, a number of 
issues related to assessing risks from mercury had not been adequately 
resolved at the time of proposal that would have allowed us to proceed 
with a quantitative analysis. We have since issued our Mercury Study 
Report to Congress, a study that has been subject to extensive peer 
review, and the Utility Study Report to Congress.322 
323 With today's rule, we conclude that sufficient technical 
basis exists for conducting a quantitative assessment of mercury risks 
from hazardous waste combustors. We recognize, however, that 
significant uncertainties remain and the results of our mercury 
analysis should be interpreted with caution and be used only 
qualitatively.
---------------------------------------------------------------------------

    \322\ ``Mercury Study Report to Congress, Volume III: Fate and 
Transport of Mercury in the Environment,'' U.S. Environmental 
Protection Agency, EPA-452/R-97-005, December 1997.
    \323\ ``Study of Hazardous Air Pollutant Emissions from Electric 
Utility Steam Generating Units--Final Report to Congress,'' U.S. 
Environmental Protection Agency, EPA-453/R-98-004a and b, February 
1998.
---------------------------------------------------------------------------

    Although the mercury analysis that accompanies today's rule is 
patterned after the analysis done for the Mercury Study, there are 
differences between the two studies in the methods used. The model we 
used for evaluating the fate and transport of mercury in lakes is the 
same as the IEM-2M model used in the Mercury Study Report to Congress. 
However, modifications were made to adapt it for use with rivers and 
streams.324 Both studies used the ISC air dispersion model 
for modeling wet deposition of mercury. However, for the Mercury Study 
the ISC model was modified to include dry deposition of mercury vapor 
whereas, for the current analysis, we used a simplified treatment of 
dry vapor deposition. In the Mercury Study, air modeling was carried 
out to a distance of 50 kilometers whereas, for the current analysis, 
air modeling (and, therefore, the effective size of the modeled 
watersheds) was limited to a distance of 20 kilometers. Long-range 
transport of mercury emissions (beyond 50 kilometers) was considered in 
the Mercury Study but was not included in the current analysis. In the 
Mercury Study, a large number of different sources were investigated to 
identify whether reductions in anthropogenic or environmental sources 
of mercury would reduce the total exposures of mercury to the general 
population. The current analysis was designed to assess what reductions 
may occur in incremental exposures from specific industrial sources of 
mercury to specific individuals rather than what reductions would occur 
in total exposures of mercury. Also, the Mercury Study modeled 
exposures under varying background assumptions, but the current 
analysis did not assess the impact that variable background 
concentrations would have on the risk results. In addition, the Mercury 
Study received external peer review, whereas we have not conducted an 
external peer review of the current analysis.
---------------------------------------------------------------------------

    \324\ For a discussion of the mercury surface water model, see 
the background document, ``Human Health and Ecological Risk 
Assessment Support to the Development of Technical Standards for 
Emissions from Combustion Units Burning Hazardous Wastes: Background 
Document--Final Report,'' July, 1999.
---------------------------------------------------------------------------

    In addition, there are a variety of uncertainties related to the 
fate and transport of mercury in the environment, such as the 
deposition of mercury emitted to the atmosphere via wet and dry removal 
processes, the transport of mercury deposited in upland areas of a 
watershed to a body of water, and the disposition of mercury in the 
water body itself, including methylation and demethylation processes, 
sequestering in the water column and sediments, and uptake in aquatic 
organisms. Furthermore, the form of mercury emitted by a given facility 
is thought to be a determining factor in the fate and transport of 
mercury in the atmosphere. Only limited data are available on the form 
of the mercury emitted from hazardous waste combustors. A more complete 
discussion of the uncertainties related to the fate and transport of 
mercury may be found in the Mercury Study Report to Congress.
    Also important to consider is that the reference dose for methyl 
mercury represents a ``no-effects'' level that is presumed to be 
without appreciable risk. We used an uncertainty factor of 10 to derive 
the reference dose for methyl mercury from a benchmark dose that 
represents the lower 95% confidence level for the 10% incidence rate of 
neurologic abnormalities in children.325 Therefore, there is 
a margin of safety between the reference dose and the level 
corresponding to the threshold for adverse effects, as indicated by the 
human health data. Furthermore, we applied the reference dose, which 
was developed for maternal exposures, to childhood exposures. This 
introduces additional uncertainty in the risk estimates for children. 
Additional uncertainties associated with assessing individual mercury 
risks to nonsubsistence populations and subsistence receptors are 
discussed under the ``Human Health Risk Characterization'' section 
below.
---------------------------------------------------------------------------

    \325\ The uncertainty factor is intended to cover three areas of 
uncertainty: Lack of data from a two-generation reproductive assay; 
variability in the human population, in particular the wide 
variation in the distribution and biological half-life of methyl 
mercury; and lack of data on long term sequelae of developmental 
effects.
---------------------------------------------------------------------------

    We do not know the direction or magnitude of many of the 
uncertainties discussed above and did not attempt to quantify the 
overall uncertainty of the analysis. Thus, the cumulative impact of 
these uncertainties is unknown, and the uncertainties implicit in the 
quantitative mercury analysis continue to be sufficiently great so as 
to limit its ultimate use for decision-making. Therefore, we have used 
the quantitative assessment to make qualitative judgments about the 
risks from mercury but have not relied on the quantitative assessment 
(nor do we believe it is appropriate) to draw quantitative conclusions 
about the risks associated with particular national emissions 
standards.
F. How Were Risks From Dioxins Evaluated?
    Few changes have been made to the methods used for assessing risk 
from dioxins since proposal. Some commenters thought we should modify 
the toxicity equivalence factors that are used to characterize the 
relative risk from 2,3,7,8-chlorine substituted congeners relative to 
that from 2,3,7,8,-tetrachlorodibenzo(p)dioxin. As a matter of policy, 
we continue to use the international consensus values that were 
published by EPA in 1989. We are aware that revisions to the toxicity 
equivalence factors are being considered by the international 
scientific community. However, we have not adopted revised values and 
continue to use the 1989 toxicity equivalence factors.
    We have changed the data being relied upon to characterize the 
bioaccumulation of dioxins in fish. Specifically, we believe that the 
biota-

[[Page 53000]]

sediment accumulation factors used at proposal, which were derived from 
data for the Great Lakes, significantly understate the bioaccumulation 
potential in aquatic systems that have recent and ongoing 
contamination. Studies in Sweden and elsewhere show that where 
contamination is ongoing, biota-sediment accumulation factors may be 
higher by as much as an order of magnitude or more relative to the 
Great Lakes and other aquatic systems where levels in biota are 
influenced primarily by past contamination. For the risk assessment for 
today's rule, biota-sediment accumulation factors were derived from 
data collected by the Connecticut Department of Environmental 
Protection. The Connecticut study, which is discussed in detail in the 
dioxin reassessment, involved extensive monitoring of soils, sediments, 
and fish near resource recovery facilities operating in the 
state.326 The data show biota-sediment accumulation factors 
that are a factor of two to nine times higher (depending on the 
individual congener) than those used previously.
---------------------------------------------------------------------------

    \326\ ``Estimating Exposure to Dioxin-Like Compounds, Volume 
III: Site-Specfic Assessment Procedures, U.S. Environmental 
Protection Agency, External Review Draft, EPA/600/6-88/005Cc, June 
1994
---------------------------------------------------------------------------

G. How Were Risks from Lead Evaluated?
    Risks from exposures to lead were assessed at proposal by comparing 
model-predicted lead levels in soil to a health-based soil benchmark 
criterion. Commenters pointed out that there are pathways of exposure 
other than those related to soils and that we should look at the 
overall impact of lead emissions on blood lead levels in children. We 
agree with these comments and have modified the risk assessment to 
include other pathways of exposure such as inhalation and dietary 
exposures, in addition to soil ingestion. The revised assessment 
employs the Intake/Exposure Uptake BioKinetic model to assess the 
incremental impact of lead intake on blood lead levels in children. The 
results of the blood lead modeling are used together with information 
on background levels of blood lead in the general population to 
estimate the number of children whose blood levels exceed 10 micrograms 
per deciliter. Our goal is to reduce children's blood lead to below 
this level.
H. What Analytical Framework Was Used To Assess Human Exposures and 
Risk?
    As a result of the public and peer review comments received on the 
risk assessment at proposal, we modified the analysis to focus on the 
entire population of persons that are exposed to facility emissions 
rather than persons living on a few individual farms and residences. A 
study area was defined for each sample facility as the area surrounding 
the facility out to a distance of 20 kilometers (or about 12 miles). 
All persons residing within the study area were included in the 
analysis.327 The study area was divided up into sixteen (16) 
sectors defined by the intersection of rings at two, five, ten and 
twenty kilometers and radii extending to the north, south, east, and 
west. For each sector, census data were used to estimate the population 
of those persons living in farm households by type of farm and the 
population of those persons living in non-farm households. Census data 
were also used to determine the age of all household members. Four age 
groups were delineated: Preschoolers (0 to 5 years), preteens (6 to 11 
years), adolescents (12 to 19 years) and adults (20 years and older).
---------------------------------------------------------------------------

    \327\ Because the analysis at proposal indicated that exposures 
beyond 20 kilometers were well below levels of concern, we did not 
consider persons exposed to facility emissions that are transported 
beyond 20 kilometers. Also, as discussed elsewhere, the risk 
assessment was peer reviewed in accordance with EPA guidelines, and 
peer reviewes did not comment that the range of the local scale 
study area was insufficient (or recommend that it be increased to 50 
or more kilometers).
---------------------------------------------------------------------------

    Within each study area, three or four bodies of water were chosen 
for analysis based on their proximity to the sample facility and the 
likelihood of their being used for recreational purposes, as indicated 
by factors such as size and accessibility. Water bodies were also 
chosen if they were used to supply drinking water to the surrounding 
community. The watershed of each water body was delineated out to a 
distance of 20 kilometers from the facility.
    We conducted a multi-pathway exposure analysis for all the human 
receptors considered in the risk assessment. Household members 
regardless of the type of household were assumed to be exposed to 
facility emissions through direct inhalation and incidental ingestion 
of soil. In addition, in study areas where surface waters are used for 
drinking water, household members were also assumed to be exposed 
through tap water ingestion. A portion of non-farm households were 
assumed to engage in home gardening based on the prevalence of home 
gardening in national surveys. Farm households were assumed to consume 
the primary food commodity produced on the farm. This contrasts with 
the subsistence farmer who was assumed to consume predominantly home-
produced foods, including meat, milk, poultry, fish, and eggs, as well 
as fruits and vegetables. For the purpose of characterizing the range 
of risks that could result from subsistence farming, it was assumed 
that a subsistence farm was located in every sector in a given study 
area. A portion of the households in each study area were assumed to 
engage in recreational fishing based on the prevalence of recreational 
fishing in national surveys. It was assumed that individual 
recreational anglers would fish at all of the water bodies delineated 
in a given study area. In contrast, households engaged in subsistence 
fishing were assumed to consume fish from only a single body of water. 
For the purpose of characterizing the range of risks that could result 
from subsistence fishing, the assumption was made that every body of 
water delineated in a given study area was used for subsistence 
fishing.
    Air dispersion and deposition modeling were performed for each 
study area at all sample facilities using facility-specific information 
on stack configuration and emissions, along with site-specific 
meteorological data, terrain data (in areas of elevated terrain), and 
land use data. Air modeling was conducted to a distance of 20 
kilometers. Long-range transport of emissions beyond this distance was 
not considered. Bioaccumulation in the terrestrial food chain was 
modeled from estimates of deposition and uptake in plants and 
subsequent uptake in agricultural livestock from consumption of forage 
and silage. Bioaccumulation in the aquatic food chain was modeled from 
estimates of deposition to watershed soils (and subsequent soil erosion 
and runoff) and direct deposition to water bodies and subsequent uptake 
in fish. Surface water modeling was conducted for each body of water 
using site-specific information relative to watershed size, surface 
runoff, soil erosion, water body size, and dilution flow.
    Exposure modeling was performed using central tendency exposure 
factors (e.g., duration of exposure and daily food intake) for all 
receptor populations. As noted below, an exposure variability analysis 
was also performed for selected constituents and receptor populations 
using exposure factor distributions. Exposure pathways varied depending 
on the particular human receptor and the types of activities that lead 
to human exposures. Age-specific rates of mean daily food intake and 
media contact rates, in conjunction with sector-specific media 
concentrations and concentrations in food, were used

[[Page 53001]]

to calculate the total (administered or potential) dose from all 
exposure pathways combined. Lifetime average daily dose was used as the 
exposure metric for assessing cancer risk and average daily dose 
(reflecting less than lifetime exposure) was used for assessing risks 
of non-cancer effects.
    We estimated the risk of developing cancer from the estimated 
lifetime average daily dose and the slope of the dose-response curve. A 
cancer slope factor is derived from either human or animal data and is 
taken as the upper bound on the slope of the dose-response curve in the 
low-dose region, generally assumed to be linear, expressed as a 
lifetime excess cancer risk per unit exposure. Total carcinogenic risk 
was determined for each receptor population assuming additivity. The 
same approach was used for estimating cancer risks in both adults and 
children. This is also the same approach we used at proposal for 
estimating lifetime cancer risks stemming from childhood exposures. 
However, individuals exposed to carcinogens in the first few years of 
life may be at increased risk of developing cancer. For this reason, we 
recognize that significant uncertainties and unknowns exist regarding 
the estimation of lifetime cancer risks in children. Although the risk 
assessment at proposal was externally peer reviewed, EPA's charge to 
the peer review panel did not specifically identify the issue of cancer 
risk in children and the peer review panel did not address it.
    To characterize the potential risk of non-cancer effects, we 
compared the average daily dose (reflecting less than lifetime 
exposure) to a reference dose and expressed the result as a ratio or 
hazard quotient. The reference dose is an estimate of a daily exposure 
to the human population, including sensitive subgroups, that is likely 
to be without an appreciable risk of deleterious effects during a 
lifetime. The hazard quotient, by indicating how close the average 
daily dose is to the reference dose, is a measure of relative risk. 
However, the hazard quotient is not an absolute measure of risk. For 
inhalation exposures, we compared modeled air concentrations to a 
reference concentration and expressed the result as a ratio or 
inhalation hazard quotient. The reference concentration is an estimate 
of a concentration in air that is likely to be without an appreciable 
risk of deleterious effects in the human population, including 
sensitive subgroups, from continuous exposures over a lifetime. In 
addition, inhalation and ingestion hazard indices were generated for 
each receptor population by adding the constituent-specific hazard 
quotients by route of exposure. The hazard index is an indicator of the 
potential for risk from exposures to chemical mixtures.
    For dioxins, we used a margin of exposure approach to assess the 
potential risks of non-cancer effects. The average daily dose, in terms 
of 2,3,7,8-TCDD toxicity equivalents (TEQ), was compared to background 
TEQ exposures in the general population and expressed as a ratio or 
incremental margin of exposure. An incremental margin of exposure was 
generated for infants exposed through intake of breast milk and for 
other age groups exposed through dietary intake and other pathways of 
exposure. For lead, we characterized the risk of adverse effects in 
children by modeling body burden levels in blood that result from 
intake of lead in the diet, direct inhalation, and incidental soil 
ingestion and comparing these levels to levels at which community-wide 
efforts aimed at prevention of elevated blood levels are indicated.
    Distributions of individual risk were generated for a given 
category of sources by weighting the individual risks using sector-
specific population weights and facility-specific sampling weights. 
Such distributions, which were derived using central tendency exposure 
factors, were generated for all constituents and receptor populations. 
In addition, for those receptor populations and chemical constituents 
that exhibited risks within an order of magnitude of a potential level 
of concern (using central tendency exposure factors), we performed an 
exposure variability analysis. Normalized, age-specific distributions 
of food intake and exposure duration were used to adjust the risk 
estimates to generate a distribution of risks in each sector. For 
children, food intake changes significantly with age, which can affect 
the lifetime average daily dose. To adjust for this, a life table 
analysis was conducted in which individuals were followed over the 
duration of exposure to arrive at an age adjustment factor. The 
individual sector distributions were combined for a given source 
category using Monte Carlo sampling and the appropriate sector-specific 
population weights and facility-specific sampling weights.
    Estimates of population risk, or the incidence of health effects in 
the exposed population, were made for selected receptor populations and 
chemical constituents. Local excess cancer incidence was estimated from 
the mean individual risk for a given sector and the number of persons 
who reside in a sector. These sector-specific cancer incidence rates 
were then adjusted using facility-specific sampling weights and summed 
for a given category of sources. Cancer incidence associated with the 
consumption of dioxin contaminated beef, pork, and milk by the general 
population was estimated at the sector level from the number of dairy 
cattle and the number of beef cattle and hogs slaughtered annually, 
adjusted using facility-specific sampling weights, and summed by source 
category. Excess incidence of lead poisoning in children (over and 
above background) was estimated at the sector level from the intake of 
lead in the diet, direct inhalation, and incidental soil ingestion, 
adjusted using facility-specific sampling weights, and summed.
    Generally speaking, incidence rates for non-cancer effects can be 
estimated from the number of persons exposed above the reference dose 
(i.e., the number of exceedances) and the annual turnover in the 
exposed population. However, non-cancer incidence rates of interest, 
such as the incidence of exceedances of the methyl mercury reference 
dose from consumption of freshwater fish, could not be estimated due to 
the difficulty in determining the number and frequency of visits made 
by recreational anglers to a given body of water. However, by making 
certain assumptions, it was possible to make an estimate of the portion 
of recreational anglers who consume fish from local water bodies that 
may be at risk.328
---------------------------------------------------------------------------

    \328\ The assumption is that fishing activity typical of 
recreational fishing takes place only at the particular water bodies 
delineated in the analysis.
---------------------------------------------------------------------------

    Due to concerns of commenters about the representativeness of the 
risk assessment, we also made estimates of confidence intervals about 
the risk estimates. Estimation of confidence intervals was made 
possible by virtue of the sampling design used for facility selection. 
The confidence intervals quantify the magnitude of the uncertainty of 
the risk estimates associated with sampling error only. We emphasize 
that the confidence intervals do not reflect other sources of 
uncertainty, which may be of considerably greater magnitude.
    In addition to the risk estimates for individual chemical 
constituents, we estimated the incidence of excess mortality and 
morbidity associated with particulate matter emissions. Mortality and 
morbidity estimates were made for children and the elderly, as well as 
the general population, using concentration-response functions derived 
from human epidemiological studies. Incidence rates

[[Page 53002]]

in a given sector were estimated from the size of the exposed 
population, including susceptible populations such as children and the 
elderly, and either annual mean PM10 and PM2.5 
concentrations or distributions of daily PM10 and 
PM2.5 concentrations. Morbidity effects include respiratory 
and cardiovascular illnesses requiring hospitalization, as well as 
other illnesses not requiring hospitalization, such as acute and 
chronic bronchitis, acute upper and lower respiratory symptoms, and 
asthmatic attacks. As with other incidence estimates, sector-specific 
incidence rates were adjusted using facility-specific sampling weights 
and summed for a given source category.
I. What Analytical Framework Was Used to Assess Ecological Risk?
    Public comments on the ecological assessment at proposal expressed 
the view that we should expand the assessment beyond water quality 
criteria. We agree with these commenters and have extended the 
ecological analysis to include the use of soil and sediment criteria, 
in addition to water quality criteria. Also, the analysis was expanded 
to include additional metals that are of ecological concern, such as 
mercury and copper.
    The ecological assessment represents a screening level analysis 
that uses media-specific ecological criteria thought to be protective 
of a range of ecological receptors. Modeled surface water 
concentrations were compared to water quality criteria protective of 
aquatic life, such as algae, fish, and aquatic invertebrates, as well 
as piscivorous wildlife. Similarly, modeled soil concentrations were 
compared to soil criteria protective of the terrestrial soil community, 
as well as terrestrial plants and mammalian and avian wildlife. Modeled 
sediment concentrations were compared to sediment criteria protective 
of the benthic aquatic community. As a screening level analysis, we did 
not attempt to determine whether the specific ecological receptors upon 
which the media-specific criteria are based are actually present at a 
given site. Furthermore, we did not ascertain the occurrence of 
threatened or endangered species at individual sites. However, the 
ecological receptors upon which the media-specific criteria are based 
are commonly occurring species and may not be any less sensitive than 
other species and may be more sensitive than some, including perhaps 
threatened or endangered species.329
---------------------------------------------------------------------------

    \329\ Multiple ecological criteria were available for most 
constituents and the lowest criteria were used to establish the 
media-specific values that were in the eco-analysis. In addition, 
ecotoxicological benchmarks for mammals and birds were typically 
derived from studies involving measures of reproductive success.
---------------------------------------------------------------------------

II. How Were Human Health Risks Characterized?

    This section describes the conclusions of the human health risk 
assessment. For a full discussion of the methodology and the results of 
the assessment, see the background document for today's 
rule.330
---------------------------------------------------------------------------

    \330\ ``Human Health and Ecological Risk Assessment Support to 
the Development of Technical Standards for Emissions from Combustion 
Units Burning Hazardous Wastes: Background Document--Final Report,'' 
July 1999.
---------------------------------------------------------------------------

A. What Potential Health Hazards Were Evaluated?
    This section summarizes the potential health hazards from exposures 
to emissions from hazardous waste combustors, in particular the human 
health hazards associated with the chemical constituents evaluated in 
the risk assessment, including dioxins, mercury, lead, other metals, 
hydrogen chloride and chlorine, and particulate matter.
1. Dioxins
    A large body of evidence demonstrates that chlorinated 
dibenzo(p)dioxins and dibenzofurans can have a wide variety of health 
effects, ranging from cancer to various developmental, reproductive and 
immunological effects. Dioxins are persistent and highly 
bioaccumulative in the environment and most human exposures occur 
through consumption of foods derived from animal products such as meat, 
milk, fish, poultry, and eggs. In 1985, we developed a carcinogenic 
slope factor for 2,3,7,8-TCDD of 1.56e-4 per picogram per kilogram body 
weight per day.331 The slope factor represents the 95 
percent upper confidence limit estimate of the lifetime excess cancer 
risk. Re-analysis of data from laboratory animals and cancer in humans 
lends support to the slope factor derived in 1985, and we continue to 
use the 1985 estimate pending completion of our dioxin 
reassessment.332 333
---------------------------------------------------------------------------

    \331\ USEPA, ``Health Assessment Document for Polychlorinated 
Dibenzo-p-Dioxins,'' EPA/600/8-84-014F, September 1985.
    \332\ USEPA, ``Health Assessment Document for 2,3,7,8-
Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds,'' External 
Review Draft, EPA/600/BP-92/001b, June 1994.
    \333\ USEPA, ``Dose Response Modeling of 2,3,7,8-TCDD,'' 
Workshop Review Draft, EPA/600/P-92/100C8, January 1997.
---------------------------------------------------------------------------

    For non-cancer effects, we believe it is inappropriate to develop a 
reference dose, or level which is without appreciable risk, using 
standard uncertainty factors. This is due to the high levels of 
background exposures in the general population and the low levels at 
which effects have been seen in laboratory animals. Instead, we have 
chosen to use a margin of exposure approach in which the average daily 
dose from a given facility is compared to the average daily dose in the 
general population. The ratio of the two represents the incremental 
margin of exposure and, as such, measures the relative increase in 
exposures over background.
2. Mercury
    The most bioavailable form of mercury is methyl mercury, and most 
human exposures to methyl mercury occur through consumption of fish. 
Methyl mercury is known to cause neurological and developmental effects 
in humans at low levels. The most susceptible human population is 
thought to be developing fetuses. We have developed a reference dose 
for methyl mercury of 0.1 microgram per kilogram body weight per day 
that is presumed to be protective of the most sensitive human 
populations.334 The reference dose is based on neurotoxic 
effects observed in children exposed in utero. Although epidemiological 
studies in fish-eating populations are ongoing, we believe that the 
reference dose is the best estimate at the present time of a daily 
exposure that is likely to be without an appreciable risk of 
deleterious effects. However, because it was derived from maternal 
exposures, application of the reference dose to assess children's 
exposures carries with it additional uncertainty beyond that otherwise 
related to the data and methods used for its development.
---------------------------------------------------------------------------

    \334\ USEPA, ``Mercury Study Report to Congress,'' EPA-452/R-97-
007, December 1997.
---------------------------------------------------------------------------

3. Lead
    Exposures to lead in humans are associated with toxic effects in 
the nervous system at low doses and at higher doses in the kidneys and 
cardiovascular system. Infants and children are particularly 
susceptible to

[[Page 53003]]

the effects of lead due to behavioral characteristics such as mouthing 
behavior, heightened absorption in the respiratory and gastrointestinal 
tracts, and the intrinsic sensitivity of developing organ systems. 
Symptoms of neurotoxicity include impairment in psychomotor, auditory, 
and cognitive function. These effects extend down to levels in blood of 
at least 10 micrograms lead per deciliter. Impairment of intellectual 
development, as measured by standardized tests, is thought to occur at 
levels below 10 micrograms per deciliter. Maternal lead exposure has 
been shown to be a risk factor in premature infant mortality, lead 
being associated with reduced birth weight and decreases in gestational 
age. Lead has also been associated with hypertension in both men and 
women and, as such, may be a risk factor for coronary disease, stroke, 
and premature mortality. Although dose-response relationships have been 
developed between blood lead levels and many of these health effects, 
EPA has not applied the relationships in the HWC risk analysis due to 
uncertainties related to the relatively small changes in blood lead 
expected to occur as a consequence of the MACT standards and the 
uncertain significance of any health benefits that might be attributed 
to such changes. Instead, our characterization of risks from lead 
focuses on the reductions in blood levels themselves and EPA's goal of 
reducing blood lead in children to below 10 micrograms per deciliter.
4. Other Metals
    Metals that pose a risk for cancer include arsenic, cadmium, and 
chromium. Human epidemiological studies have shown an increase in lung 
cancer from inhalation exposures to arsenic, primarily in 
occupationally exposed individuals, and multiple internal cancers (such 
as liver, lung, kidney, and bladder), as well as skin cancer, from 
exposures to arsenic through drinking water. Human epidemiological 
studies have also shown an association between exposures to cadmium and 
lung cancer in occupational settings. These studies have been confirmed 
by animal studies which have shown significant increases in lung tumors 
from inhalation exposures to cadmium. However, cadmium administered 
orally has shown no evidence of carcinogenic response. A strong 
association between occupational exposures to chromium and lung cancer 
has been found in multiple studies. Although workers were exposed to 
both trivalent and hexavalent chromium, animal studies have shown that 
only hexavalent chromium is carcinogenic. There have been no studies 
that have reported that either hexavalent or trivalent chromium is 
carcinogenic by the oral route of exposure.
    Other metals may pose a risk of noncancer effects. For example, in 
animal studies thallium has been shown to have ocular, neurological, 
and dermatological effects and effects on blood chemistry and the 
reproductive system. Signs and symptoms of similar and other effects 
have been observed in occupational studies of thallium exposures.
5. Hydrogen Chloride
    Data on the effects of low-level inhalation exposures to hydrogen 
chloride are limited to studies in laboratory animals. Based on a 
lifetime study in rats which showed histopathological changes in the 
nasal mucosa, larynx, and trachea associated with exposures to hydrogen 
chloride, we estimated a reference concentration of 0.02 
milligrams per cubic meter. The reference concentration was derived 
from a human equivalent lowest observed adverse effects level of 6 
milligrams per cubic meter using an uncertainty factor of 300 to 
account for extrapolation from a lowest observed adverse effects level 
to a no observed adverse effects level, as well as extrapolation from 
animals to humans (including sensitive individuals).
6. Chlorine
    Chlorine gas is a potent irritant of the eyes and respiratory 
system. Based on a lifetime study in rats and mice which showed 
histopathological changes affecting all airway tissues in the nose, we 
derived an interim chronic toxicity benchmark for chlorine gas of 0.001 
milligrams per cubic meter. This value was derived from a human 
equivalent no observed adverse effects level of 0.04 milligrams per 
cubic meter and an uncertainty factor of 30 to account for 
extrapolation from animals to humans (including sensitive individuals). 
The human equivalent no observed adverse effects level from this study 
is also supported by a year-long study in monkeys.335
---------------------------------------------------------------------------

    \335\ For a complete description of the derivation of the 
chronic toxicity benchmark for chlorine, see the background 
document, ``Human Health and Ecological Risk Assessment Support to 
the Development of Technical Standards for Emissions from Combustion 
Units Burning Hazardous Wastes: Background--Final Report,'' July, 
1999.
---------------------------------------------------------------------------

B. What Are the Health Risks to Individuals Residing Near HWC 
Facilities?
    In this section, we address risks to populations that could be 
enumerated using estimation methods based on U.S. Census data and 
Census of Agriculture data. Estimates of the population of persons 
residing within 20 kilometers of hazardous waste combustion facilities 
were made for beef, dairy, produce, and pork farming households and for 
non-farm households. The number of home gardeners was estimated using 
national survey data on the portion of households that engage in home 
gardening. Estimates were made for each of four different age groups. 
In addition, population estimates were made for recreational anglers 
age 16 and older based on U.S. Fish and Wildlife Service survey data on 
recreational fishing and hunting.336
---------------------------------------------------------------------------

    \336\ However, it was not possible to determine the number of 
recreational anglers that fish specifically at water bodies located 
in the vicinity of hazardous waste combustion facilities, such as 
those that were selected for modeling analyses.
---------------------------------------------------------------------------

    The risks to individuals of carcinogenic effects are expressed as 
the estimated increase in the probability that an individual will 
develop cancer over a lifetime. For non-cancer effects, risks are 
expressed as a hazard quotient, which is the ratio of an estimate of an 
individual's exposure to a health benchmark thought to be without 
appreciable risk. Both cancer and non-cancer risks are summarized in 
terms of percentiles of the national distribution of risks to 
individuals across a combustor category. High end risks are represented 
by the 90th to 99th percentiles of the distribution. Distributions for 
only the most highly exposed receptor populations are discussed here. 
The most highly exposed population varies depending on the particular 
chemical constituent, its fate and transport in the environment, and 
the pathways that lead to human exposures. Also, 90 percent confidence 
limits are estimated for each percentile. The size of the confidence 
interval reflects sampling error which is introduced by not sampling 
all the facilities in a given category of sources.\337\ In some 
instances, estimates of the 90 percent confidence limits could not be 
made either because there were too few data points or there was 
insufficient spread in the data. For lightweight aggregate kilns, there 
is no sampling error because the sample included all known

[[Page 53004]]

hazardous waste burning lightweight aggregate kilns.
---------------------------------------------------------------------------

    \337\ A 90 percent confidence interval indicates that there is a 
10 percent chance that the actual value could lie outside the 
interval indicated, either higher or lower.
---------------------------------------------------------------------------

1. Dioxins
    For dioxins, our analysis shows that the most exposed population is 
children of dairy farmers who consume home-produced milk. High 
exposures were estimated for this population due to the relatively high 
consumption of milk by households that consume home-produced milk, the 
relatively high intake of milk by children compared to other age 
groups, and the tendency of chlorinated dioxins and furans to 
bioaccumulate in milk fat. A distribution of cancer risks for dioxins 
was generated which reflects variability in individual exposures due to 
site-specific differences in dioxin emissions, location of exposure, 
and other factors, as well as differences between individuals in 
exposure factors such as the length of exposure and the amount of milk 
consumed.
    As a result of today's rule, we project that high end lifetime 
excess cancer risks will be reduced in this population from 2 in 
100,000 (99th percentile) for both lightweight aggregate kilns and 
incinerators with waste heat recovery boilers to below one in one 
million (99th percentile) for lightweight aggregate kilns and 1 in one 
million (99th percentile, 90 percent upper confidence limit of 2 in one 
million) for incinerators with waste heat recovery boilers. For cement 
kilns, high end lifetime excess cancer risks are reduced only slightly, 
from 7 in one million (99th percentile) to 5 in one million (99th 
percentile). These reductions, which represent the reduction in the 
increment of exposure that results from dioxin emissions from hazardous 
waste combustors, are relatively small in relation to background 
exposures to dioxins generally. Considering that the number of 
individuals in the affected population is relatively small, only a few 
individuals may benefit from such reductions.
    We also project that the incremental margin of exposure relative to 
background will be reduced in the same population from 0.2 (99th 
percentile for lightweight aggregate kilns) and 0.3 (99th percentile 
for incinerators with waste heat recovery boilers, 90 percent upper 
confidence limit of 0.5) to below 0.1 across all categories of 
combustors. Therefore, the risks associated with non-cancer effects 
from hazardous waste combustors are an order of magnitude or more lower 
than any (unknown and unquantifiable) risks that may be attributable to 
background exposures.
    Unlike the distribution of cancer risks, the distribution of the 
margin of exposure reflects only site-to-site differences and does not 
reflect differences between individuals in the amount of milk consumed. 
Therefore, the exposures at the upper percentiles are likely to be 
underestimated.338 Additional uncertainty is introduced 
because background exposures to dioxins in children have not been well 
characterized.
---------------------------------------------------------------------------

    \338\ The precise extent of underestimation at the upper 
percentiles associated with variability in milk consumption is 
unknown but is expected to be a factor of two.
---------------------------------------------------------------------------

    Other uncertainties include milk consumption rates and the 
limitations of the data available to assess consumption of home-
produced milk. In addition, there are a variety of uncertainties 
related to the fate and transport of dioxins in the environment, 
including partitioning behavior into vapor and particle phases 
following release to the atmosphere and subsequent deposition via 
various wet and dry removal processes, uptake in plants such as forage 
and silage used by dairy cows for grazing and feeding, and the factors 
which affect the disposition of dioxins in dairy cattle and the extent 
of bioaccumulation in cow's milk.
2. Mercury
    For mercury, our analysis shows that the most exposed population is 
recreational anglers and their families who consume recreationally-
caught freshwater fish. This is because methyl mercury is readily 
formed in aquatic ecosystems and bioaccumulates in fish. Children have 
the highest exposures due to their higher consumption of fish, relative 
to body weight, compared to adults. Risks from exposures to methyl 
mercury are expressed here in terms of a hazard quotient, which is 
defined as the ratio of the modeled average daily dose to our reference 
dose. Although the reference dose was developed to be protective of 
exposures in utero, we applied the reference dose not just to maternal 
exposures but also to non-maternal adult and childhood exposures based 
on the presumption that the reference dose should be protective of 
neurological and developmental effects in these populations as well.
    A distribution of hazard quotients was generated that reflects 
variability in individual exposures due to site-specific differences in 
mercury emissions, location of water bodies, and other factors, as well 
as differences between individuals in the amount of fish consumed. 
Other factors, such as water body-specific differences in the extent of 
methylation of inorganic mercury and the age and species of fish 
consumed were not reflected in the risk distribution. However, it is 
unclear what effect such factors would have on the distribution given 
the high degree of variability that is attributable to the factors that 
were considered in our analysis.
    The results of our quantitative analysis for mercury are as 
follows. For cement kilns, we project that high end hazard quotients in 
adults will be reduced from a range of 0.09 to 0.4 (90th percentile, 
upper confidence limit of 0.1, and 99th percentile, respectively) at 
baseline to a range from 0.06 to 0.2 under today's rule (90th 
percentile, upper confidence limit of 0.08, and 99th percentile, 
respectively). In children, high end hazard quotients are projected to 
be reduced from a range of 0.2 to 0.8 (90th percentile, upper 
confidence limit of 0.3, and 99th percentile, respectively) at baseline 
to a range of 0.2 to 0.6 under today's rule (90th percentile, upper 
confidence limit of 0.2, and 99th percentile, respectively). For 
lightweight aggregate kilns, high end hazard quotients in both adults 
and children are below 0.1 at baseline and under today's rule. For 
incinerators, high end hazard quotients are below 0.01 in adults and 
below 0.1 in children at baseline and under today's rule. Taken 
together, these results appear to suggest that risks from mercury 
emissions (on an incremental basis) are likely to be small, although we 
cannot be certain of this for the reasons discussed below.
    The risk results for mercury are subject to a considerable degree 
of uncertainty. In addition to the uncertainties discussed above in 
``Overview of Methodology--Mercury'', there are other uncertainties 
when assessing individual mercury risks to nonsubsistence populations. 
In order to assess exposures to mercury emissions, we assumed that 
recreational anglers fish only at the water bodies within a given study 
area that were selected for modeling (and at no other water bodies) and 
that the extent of fishing activity at a given water body is related to 
the size of the water body.339 As a result, in those 
situations where relatively low fish concentrations were modeled (and 
particularly if the water body was relatively large), a large portion 
of fish were assumed to have relatively low levels of mercury 
contamination and, therefore, recreational anglers who consume 
relatively large amounts of recreationally-caught fish were estimated 
to have relatively low levels

[[Page 53005]]

of exposure. In reality, some portion of the fish consumed by 
recreational anglers is likely to be contaminated with mercury at 
levels typical of background conditions. The effect of such background 
exposures is to increase actual exposures, except perhaps at the high 
end of the exposure distribution.340
---------------------------------------------------------------------------

    \339\ Ideally, detailed information on the fishing activities of 
individual anglers, including the size of the catch taken from 
individual locations, would be used to better assess exposures from 
consumption of recreationally-caught fish.
    \340\ We have previously estimated that median exposures to 
methyl mercury in the general population from seafood consumption 
are in the range of 0.01 to 0.03 g/kg BW/day (Mercury Study 
Report to Congress, December 1997). These exposures correspond to 
hazard quotients of 0.1 to 0.3, values which (except for cement 
kilns) are higher than the 90th to 99th percentile hazard quotients 
estimated here for incremental exposures among recreational anglers.
---------------------------------------------------------------------------

    We believe that the uncertainties implicit in the quantitative 
mercury analysis continue to be sufficiently great so as to limit its 
ultimate use for decision-making. Therefore, we have used the 
quantitative analysis to make qualitative judgments about the risks 
from mercury but have not relied on the quantitative analysis (nor do 
we believe it is appropriate) to draw quantitative conclusions about 
the risks associated with the MACT standards.
3. Lead
    For lead, children are the population of primary concern for 
several reasons, including behavioral factors, absorption, and the 
susceptibility of the nervous system during a child's development. We 
have chosen to use blood lead level as the exposure metric, consistent 
with the U.S. Centers for Disease Control criteria for initiating 
intervention efforts. Lead exposures occur through a variety of 
pathways, including inhalation, incidental ingestion of soil and 
household dust, and dietary intake. Our analysis indicates that the 
population having the highest exposures are children who consume home-
produced fruits and vegetables. However, children who do not consume 
home-produced foods also have relatively high exposures due to 
incidental ingestion of soil and household dust.
    Blood lead distributions were generated that represent incremental 
exposures to lead emissions from hazardous waste combustors. These 
distributions reflect variability in individual exposures due to site-
specific differences in lead emissions, location of exposure, and other 
factors, as well as differences between individual children in behavior 
patterns, absorption, and other pharmacokinetic factors. The IEUBK 
model that was used to estimate blood lead levels considers inter-
individual variability in behavior related to lead exposure, such as 
mouthing activity. However, the model does not explicitly consider 
variability for the specific dietary pathways assessed for children of 
home gardeners, that is, consumption of home-produced fruits and 
vegetables. Therefore, the blood lead distributions may not fully 
reflect inter-individual variability that results from such individual 
differences.
    Modeled blood lead (PbB) levels can be compared with background 
exposures in the same age group (children ages 0 to 5 years) in the 
general population. The median blood lead level in children in the 
general population is 2.7 micrograms per deciliter (g/dL), and 
4.4 and 1.3 percent of children have blood lead levels that exceed 10 
and 15 g/dL, the levels at which community wide prevention and 
individual intervention efforts, respectively, are 
recommended.341 However, the percentages vary widely 
depending on such factors as race, ethnicity, income, and age of the 
housing units occupied. Children whose blood lead levels are already 
elevated are the most susceptible to further increases in blood lead 
levels.
---------------------------------------------------------------------------

    \341\ Data from the Centers for Disease Control's National 
Health and Nutrition Examination survey (NHANES III, phase 2) 
conducted from October 1991 to September 1994.
---------------------------------------------------------------------------

    As a result of today's rule, we project that high end (90th to 99th 
percentile) incremental blood lead (PbB) levels in children will 
decrease from 0.24 to 0.50 micrograms per deciliter to 0.02 to 0.03 
g/dL for cement kilns. For incinerators, incremental PbB 
levels are projected to decrease from 0.6 to 1.2 g/dL (90th to 
99th percentile) to 0.02 to 0.03 g/dL. For lightweight 
aggregate kilns, incremental PbB levels are projected to decrease from 
0.02 to 0.03 g/dL (90th to 99th percentile) to less than 0.01 
g/dL under the MACT standards. Although these reductions in 
incremental exposures represent only a fraction of the PbB level of 
concern (10 g/dL), they can be significant in children with 
PbB levels that are already elevated from exposures to other sources of 
lead. In addition, there is evidence that effects on the neurological 
development of children may occur at blood lead levels so low as to be 
essentially without a threshold. Under the MACT standards, blood lead 
levels attributable to HWCs will be one percent or less of background 
levels typical of children in the general population.
4. Other Metals
    We assessed both direct and indirect human exposures to a dozen 
different metals in addition to mercury. Exposures to non-mercury 
metals are generally quite low. Under today's rule, we project that 
lifetime excess cancer risks from exposures to carcinogenic metals 
(i.e., arsenic) will be below 1 in 10 million for all source 
categories. Hazard quotients for all source categories are projected to 
be at or below 0.01 (99th percentile) for all non-mercury metals under 
the MACT standards. These risks reflect variability in individual 
exposures due to site-specific differences in emissions, location of 
exposure, and other factors. However, the risks do not reflect 
differences between individuals in exposure factors such as the length 
of exposure and the amount of food ingested. Therefore, we may have 
underestimated risks at the upper percentiles of the 
distribution.342 A full exposure factor variability analysis 
was not carried out because the risks using mean exposure factors are 
comparatively low. Risks from exposure to metals are also subject to 
uncertainty related to modeling of fate and transport in the 
environment such as deposition of airborne metals to soils, forage, and 
silage and subsequent uptake in farm animals.
---------------------------------------------------------------------------

    \342\ For dioxins, inclusion of exposure factor variability 
increased the risk of cancer at the upper (90th to 99th) percentiles 
by less than a factor of two to a factor of five. However, the 
effect on the distribution of risks could differ for metals 
depending on the health effect of concern (i.e., cancer versus non-
cancer), the pathway of exposure, and relative differences in the 
site-to-site variability of emissions.
---------------------------------------------------------------------------

5. Inhalation Carcinogens
    We also assessed the combined cancer risk associated with 
inhalation exposures to all inhalation carcinogens, assuming additivity 
of the risks from individual compounds. The populations that have the 
highest inhalation exposures are adult farm or non-farm residents. 
Adults have the longest exposure duration relative to other age groups 
and adult farmers have less mobility and, therefore, longer durations 
of exposure than non-farm residents. However, depending on the location 
of farms and non-farm households, adult non-farm residents can have 
lifetime average exposures that are as high as adult farm residents.
    Under today's rule, we project that lifetime excess cancer risks 
from inhalation exposures will be below 1 in 10 million for all source 
categories. The risks for inhalation carcinogens reflect variability in 
individual exposures due to site-specific differences in metals 
emissions, location of exposure, and other factors. However, they do 
not reflect differences between individuals

[[Page 53006]]

in the length of exposure or other exposure factors. Therefore, we may 
have underestimated risks at the upper percentiles of the 
distribution.343 A full exposure factor variability analysis 
was not carried out for inhalation carcinogens because the risks using 
mean exposure factors are comparatively low.
---------------------------------------------------------------------------

    \343\ The precise extent of underestimation at the upper 
percentiles associated with variability in the duration of exposure 
is unknown but is expected to be a factor of three or less.
---------------------------------------------------------------------------

    Estimates of inhalation risks are subject to a number of 
uncertainties. Individuals spend a majority of their time indoors and 
it is uncertain how representative modeled, outdoor, ambient air 
concentrations are of concentrations indoors. Also, the daily 
activities of individuals living in the vicinity of a given facility 
will tend to moderate actual exposures compared to modeled exposures at 
a fixed location. Meteorological information was generally obtained 
from locations well removed from modeled facilities and, therefore, may 
not be representative of conditions in the immediate vicinity of the 
stack. Limited information was available on the size of structures 
located near or adjacent to stacks at the modeled facilities. Building 
downwash, that can result from the presence of such structures, may 
significantly increase ground-level ambient air concentrations, 
particularly at locations that are relatively close to the point of 
release. In addition, the effect of elevated terrain was only 
considered when the terrain rose above the height of the stack. 
However, elevated terrain below stack height can lead to an increase in 
ground-level concentrations depending on the distance from the stack. 
Nevertheless, our projections of inhalation cancer risks are 
sufficiently low that we do not believe the uncertainties introduced by 
these factors impacts our conclusion that these risks are relatively 
low.
6. Other Inhalation Exposures
    Of the compounds we evaluated that are not carcinogenic, the 
highest inhalation exposures are for hydrogen chloride and chlorine 
gas. We express the risks from these in terms of an 
inhalation hazard quotient, which is defined as the ratio of the 
modeled air concentration to our reference concentration. The receptor 
population with the highest inhalation hazard quotients is variable and 
depends on site-to-site differences in the location of farm and non-
farm households and differences in emissions. A distribution of hazard 
quotients was generated that reflects variability in individual 
exposures due to site-specific differences in chlorine emissions, 
location of exposure, and other factors. However, the distribution does 
not reflect individual differences in activity patterns or breathing 
rates.344 Also, because the reference concentration is 
intended to be protective of long-term, chronic exposures over a 
lifetime, the distribution does not reflect temporal variations in 
exposure.345
---------------------------------------------------------------------------

    \344\ Differences in breathing rates are not considered because 
the exposure factors used in deriving the reference concentration 
are fixed.
    \345\ Although short-term exposures to hydrogen chloride and 
chlorine gas resulting from routine releases can be significantly 
higher than long-term exposures, we do not believe that such 
exposures are high enough to pose a health concern because the 
threshold for acute effects is quite high in comparison to that for 
chronic effects.
---------------------------------------------------------------------------

    Under today's rule, we project that inhalation hazard quotients 
will be at or below 0.01 for both hydrogen chloride and chlorine gas 
for all source categories. The same uncertainties related to indoor 
versus outdoor concentrations and atmospheric dispersion modeling are 
also applicable to hydrogen chloride and chlorine. However, our 
projections of non-cancer inhalation risks are sufficiently low that we 
do not believe the uncertainties impact our conclusion that these risks 
are relatively low.
C. What Are the Potential Health Risks to Highly Exposed Individuals?
    We also assessed exposures to individuals that could be more highly 
exposed than the populations that could be characterized using census 
data. These include persons engaged in subsistence activities such as 
farming and fishing. Although the frequency of these activities is 
unknown, such activities do occur in some segments of the U.S. 
population, and we believe that it is important to evaluate risks 
associated with such activities. In addition, risks associated with 
subsistence farming place a bound on potential risks to farmers who 
raise more than one type of livestock. Information on the numbers of 
farms that produce more than one food commodity (e.g., beef and milk) 
is not available from the U.S. Census of Agriculture. Therefore, in 
assessing risks to farm populations, we may have underestimated the 
risks to farmers and their families that consume more than one type of 
home-produced food commodity.
    We assumed that subsistence farmers obtain substantially all of 
their dietary intake from home-produced foods, including meats, milk, 
poultry, fish, and fruits and vegetables. We used data on the mean rate 
of consumption of home-produced foods in households that consume home-
produced foods to estimate the average daily intakes from subsistence 
farming. For subsistence fishing, we used data on the mean rate of fish 
consumption among Native American tribes that rely on fish for a major 
part of their dietary intake.
    We do not have specific information on the existence or location of 
subsistence farms or water bodies used for subsistence fishing at sites 
where hazardous waste combustors are located. Therefore, we 
hypothetically assumed that subsistence farming does occur at each of 
the modeled facilities and, furthermore, that it occurs within each of 
the sixteen sectors within a study area. We also assumed that 
subsistence fishing takes places at each of the modeled water bodies. 
The results of the analysis are summarized in the form of frequency 
distributions of individual risk. The distributions must be interpreted 
in relation to the frequency of the modeled scenarios and not the 
likelihood of such exposures actually occurring.346
---------------------------------------------------------------------------

    \346\ Moreover, the modeled scenarios cannot be considered 
equally probable because the sectors in which farms were located are 
of unequal area, being much smaller closer to a facility and much 
larger farther away and because any particular sector may be more or 
less likely to support farming activities depending on soils, 
precipitation, existing land uses, and other conditions. Similarly, 
the modeled water bodies may be more or less likely to support 
intensive fishing activity depending on their size, productivity, 
and other characteristics.
---------------------------------------------------------------------------

    The risk results for subsistence receptors are highly uncertain, 
primarily due to the lack of information on the location of subsistence 
farms (or even the occurrence of subsistence farms within the study 
area of a given facility) and the assumption that individuals engaged 
in subsistence farming obtain essentially their entire dietary intake 
from home-produced foods.
1. Dioxins
    Under today's rule, we project that lifetime excess cancer risks 
from dioxin exposures associated with subsistence farming will be below 
1 in 100,000 for all categories of combustors, with the exception of 
cement kilns at the lowest frequency of occurrence. The lifetime excess 
cancer risk for cement kilns is estimated to be 2 in 100,000 at a 
frequency of 1 percent. This indicates that only 1 in 100 sectors are 
expected to have risks of this magnitude or greater, assuming that 
subsistence farms are located in all sectors at all hazardous waste 
burning cement kilns. However, because the sectors increase in size 
with increasing distance, the probability that a subsistence farm would 
be exposed to

[[Page 53007]]

this level of risk is probably considerably less than 1 percent.
    We project that the incremental margin of exposure relative to 
background will be reduced to 0.1 or below for incinerators under 
today's rule except at the lowest frequency of occurrence (i.e., 1 
percent) for which a margin of exposure of 0.2 is projected. However, 
the incremental margins of exposure for cement kilns and lightweight 
aggregate kilns are projected to remain above 0.1 at a frequency of 10 
percent or greater (ranging up to 0.2 at a frequency of 5 percent for 
lightweight aggregate kilns and 0.7 at a frequency of 1 percent for 
cement kilns). This indicates that more than 1 in 10 sectors are 
expected to have risks associated with non-cancer effects that are 
within an order of magnitude of any (unknown and unquantifiable) risks 
that may be attributable to background exposures. However, for the 
reasons stated previously, the probability that a subsistence farm 
would be exposed to this level of risk is probably considerably lower 
than indicated by the number of sectors.
    Under today's rule, we project lifetime excess cancer risks from 
dioxin exposures associated with subsistence fishing will be below 1 in 
one million for incinerators and lightweight aggregate kilns. For 
cement kilns, high end cancer risks under today's rule range from 3 in 
one million to 4 in one million (at frequencies of 10 and 5 percent, 
respectively) in adults and from 2 in one million to 4 in one million 
(at frequencies of 10 and 5 percent, respectively) in children (6 to 11 
years of age). We project that the incremental margin of exposure 
relative to background will be below 0.1 for subsistence fishing for 
both children and adults for all categories of combustors under today's 
rule.
2. Metals
    Our analysis indicates that the highest risks from metals (other 
than mercury) are from arsenic, thallium, and lead. Under today's rule, 
we project that lifetime excess cancer risks from arsenic exposures 
associated with subsistence farming will be below 1 in one million for 
all source categories. Hazard quotients for thallium are projected to 
be at or below 0.01 (99th percentile) under today's rule, except for 
cement kilns. For cement kilns, hazard quotients for thallium are 
projected to range from 0.03 to 0.4 (90th to 99th percentiles). 
Incremental blood lead levels are projected to be at or below 0.03 
g/dL for all source categories under today's rule. Blood lead 
at these levels are about one percent of background levels typical of 
children in the general population.
3. Mercury
    From the results of our quantitative analysis we project that, 
under today's rule, hazard quotients for incremental exposures to 
mercury associated with subsistence fishing will be at or below 1 in 
both adults and children. These results apply to incinerators, 
lightweight aggregate kilns, and cement kilns at the very lowest 
frequency of occurrence that was analyzed (i.e., 1 percent).
    The risk results for mercury are subject to a considerable degree 
of uncertainty. In addition to the uncertainties discussed above in 
``Overview of Methodology--Mercury'', there are other uncertainties 
when assessing individual mercury risks to subsistence receptors. We 
assumed that individuals engaged in subsistence fishing obtain all the 
fish they consume from a single water body. To the extent that 
individuals may fish at more than one water body, the effect of this 
assumption may be to exaggerate the risk from water bodies having 
relatively high modeled fish concentrations.
    The uncertainties implicit in the quantitative mercury analysis 
continue to be sufficiently great so as to limit its ultimate use for 
decision-making. Therefore, we have used the quantitative analysis to 
make qualitative judgments about the risks from mercury but have not 
relied on the quantitative analysis (nor do we believe it is 
appropriate) to draw quantitative conclusions about the risks 
associated with the MACT standards.
D. What Is the Incidence of Adverse Health Effects in the Population?
    We estimated the overall risk to human receptor populations for 
those chemical constituents that posed the highest individual risks and 
whose populations could be enumerated. These included excess cancer 
incidence in the general population from the consumption of 
agricultural commodities produced in the vicinity of hazardous waste 
burning facilities, excess cancer incidence in the local population, 
and excess incidence of children with elevated blood lead levels. In 
addition, we estimated the avoided incidence of mortality and morbidity 
in the local population associated with reductions in exposures to 
particulate matter emissions.347 Incidence is generally 
expressed in terms of the annual number of new cases of disease in the 
exposed population. However, for diseases such as cancer which have a 
long latency period, the annual incidence represents the lifetime 
incidence associated with an exposure of one year. For diseases with 
recurring symptoms, the annual incidence represents the number of 
episodes of disease over a year's time.
---------------------------------------------------------------------------

    \347\ Excess incidence refers to the incidence of disease beyond 
that which would otherwise be observed in the population, absent 
exposures to the sources in question. Avoided incidence is the 
reduction in incidence of disease in the population that would be 
expected from a reduction in exposures to the sources in question.
---------------------------------------------------------------------------

1. Cancer Risk in the General Population
    Agricultural commodities produced in the vicinity of hazardous 
waste combustors may be consumed by the general population (i.e., 
individuals who reside outside the study area). Commodities such as 
meat and milk may be contaminated with dioxins and, therefore, pose 
some risk to individuals that consume them. We estimated the amount of 
``diet accessible'' dioxin in meat and milk produced at hazardous waste 
combustors that would be consumed by the general population and 
estimated the number of additional cancer cases that could result from 
such exposures. The approach is predicated on the assumption that 
cancer risks follow a linear, no-threshold model in the low dose 
region.
    Our agricultural commodity analysis indicates that, as a result of 
today's rule, annual excess cancer incidence in the general population 
will be reduced from 0.5 cases per year (90 percent confidence 
interval, 0.4 to 0.6) to 0.1 cases per year (90 percent confidence 
interval, 0.1 to 0.2). Most of the risk is associated with the 
consumption of milk and other dairy products. The combustor categories 
that contribute most to the reduction are incinerators with waste heat 
recovery boilers and lightweight aggregate kilns.
2. Cancer Risk in the Local Population
    Individuals that live and work in the vicinity of hazardous waste 
combustors are exposed to a number of compounds that are carcinogenic 
by oral or inhalation routes of exposure or both. These include dioxin, 
arsenic, beryllium, cadmium, chromium, and nickel. We estimated the 
annual cancer incidence in each of the enumerated receptor populations 
based on the mean individual risk in each sector and sector-specific 
population estimates. The resulting incidence estimates were weighted 
using facility-specific sampling weights and summed.
    Our analysis of cancer risks in the local population indicates 
that, as a result of today's rule, annual excess

[[Page 53008]]

cancer incidence will be reduced from 0.1 cases per year (90 percent 
confidence interval, 0.08 to 0.2) to 0.02 cases per year (90 percent 
confidence interval, 0.01 to 0.03). Nearly all of the risk reduction, 
which occurs almost entirely among non-farm residents, is attributable 
to incinerators and results mainly from reductions in emissions of 
metals, primarily arsenic, cadmium, and chromium.
3. Risks From Lead Emissions
    Children that live near hazardous waste combustor are exposed to 
lead emissions through the diet and through inhalation and incidental 
soil ingestion. Children that already have elevated blood lead levels 
may have their levels further increased as a result of such exposures, 
some of whom may have their blood lead levels increased beyond 10 
g/dL. We estimated the increase, or excess incidence, of 
elevated blood levels above 10 g/dL by estimating the number 
of children in each sector with blood lead levels above 10 g/
dL as a result of background exposure and subtracting that from the 
number of children above 10 g/dL as a result of both 
background exposure and incremental exposures from hazardous waste 
combustors. This estimate represents the annual rate of increase in the 
number of children with elevated blood lead beyond background.
    Our analysis indicates that, as a result of today's rule, the 
excess incidence of elevated blood lead will be reduced from 7 cases 
per year to less than 0.1 cases per year. The reduction is primarily 
attributable to incinerators, although a small reduction (0.4 cases per 
year) is attributable to cement kilns. These reductions occur entirely 
among non-farm residents. Children of minority and low income 
households generally have higher background exposures to lead and are 
more likely to have blood levels elevated above 10 g/dL than 
children from other demographic groups and, therefore, are more likely 
to benefit from reductions in lead exposures. However, our analysis did 
not consider the influence of such socioeconomic factors. For this 
reason, we believe that we may have underestimated the reductions in 
excess incidence of elevated blood lead levels, including potential 
reductions attributable to cement kilns and lightweight aggregate 
kilns.
4. Risks From Emissions of Particulate Matter
    Human epidemiological studies have demonstrated a correlation 
between community morbidity and mortality and ambient levels of 
particulate matter, particularly fine particulate matter (below 2.5 or 
10 microns in diameter, depending on the study), across a wide variety 
of geographic settings. Lower particulate matter is associated with 
lower mortality, lower rates of hospital admissions, and a lower 
incidence of respiratory disease. Concentration-response functions for 
various health endpoints have been derived from these studies, and we 
used these functions to estimate the reduction in the incidence of 
mortality and morbidity associated with a reduction in emissions of 
particulate matter.
    Our analysis indicates that, as a result of today's rule, there 
will be between 1 and 4 fewer premature mortalities per year associated 
with particulate matter emissions (depending on which study is used). 
In addition, we project there will be 6 fewer hospitalizations, 25 
fewer cases of chronic bronchitis, 180 fewer cases of lower respiratory 
disease, per year.
    The mortality estimates are subject to some uncertainty due to the 
fact that the lower estimate (which is derived from long-term studies) 
assumes no threshold for effects and the upper estimate (which is 
derived from short-term studies) may include mortalities that are 
premature by as little as a few days. The no threshold assumption may 
be appropriate, however, considering that the reduction in mortality is 
projected to occur entirely from incinerators, especially on-site 
incinerators. Such incinerators are located at manufacturing facilities 
that are likely to have other particulate matter emissions and both on-
site, and commercial incinerators are typically located in industrial 
areas where there may be many other sources of particulate matter 
emissions, resulting in ambient particulate matter levels that are well 
above any threshold. Also, because the particulate matter modeling was 
conducted to 20 rather than 50 kilometers, the inhalation risks may be 
understated, especially from PM that is 2.5 microns in diameter and 
smaller which can be transported over long distances from HWCs.

III. What Is the Potential for Adverse Ecological Effects?

    The ecological assessment is based on a screening level analysis in 
which model-estimated media concentrations are compared to media-
specific ecotoxicological criteria that are protective of multiple 
ecological receptors. The analysis used an ecological hazard quotient 
as the metric for assessing ecological risk. The ecological hazard 
quotient is the ratio of the model-estimated media concentration to the 
ecotoxicological criterion. Hazard quotients above 1 suggest that a 
potential for adverse ecological effects may exist. Ecotoxicological 
criteria for soils, surface waters, and sediments were used in the 
analysis. Ecotoxicological criteria for soil are intended to be broadly 
protective of terrestrial ecosystems, including the soil community, 
terrestrial plants, and consumers such as mammals and birds. 
Ecotoxicological criteria for surface water are intended to be 
protective of the aquatic community, including fish and aquatic 
invertebrates, primary producers such as algae and aquatic plants, and 
fish-eating mammals and birds. Sediment criteria are intended to be 
protective of the benthic community. The analysis was conducted for 
dioxins, mercury, and fourteen other metals. Only the results for 
dioxins and mercury are discussed here. Very low or no potential for 
ecological risk was found for the other metals.348 For a 
full discussion of the ecological assessment, see the background 
document for today's rule.349
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    \348\ Although minor exceedances of the ecotoxicological 
criteria for lead were noted for incinerators, the exceedances were 
eliminated under today's rule.
    \349\ ``Human Health and Ecological Risk Assessment Support to 
the Development of Technical Standards for Emissions from Combustion 
Units Burning Hazardous Wastes: Background Document--Final Report,'' 
July, 1999.
---------------------------------------------------------------------------

A. Dioxins
    A variation on the general screening level approach was used for 
assessing ecological risks from dioxins in surface water. Rather than 
basing the assessment on ambient water quality criteria for the 
protection of wildlife, ecotoxicological benchmarks for 2,3,7,8-
tetrachlorodibenzo(p)dioxin (TCDD) for fish-eating birds and mammals 
(i.e., no observed adverse effects levels) were used to make a direct 
comparison with estimated intakes of dioxins in fish in terms of 
2,3,7,8-TCDD toxicity equivalents (TEQ). This approach accounts for the 
different rates of bioaccumulation of the various 2,3,7,8 
dibenzo(p)dioxin and dibenzofuran congeners and avoids the conservatism 
of comparing an ambient water quality criterion for 2,3,7,8-TCDD to 
model-estimated water concentrations in terms of 2,3,7,8-TCDD TEQs. The 
results of our analysis indicate no exceedances of the ecotoxicological 
benchmarks for 2,3,7,8-TCDD for any category of hazardous waste 
combustors. One limitation of the ecological assessment for dioxins is 
that water quality criteria for the protection of aquatic life are not

[[Page 53009]]

available. However, fish and aquatic invertebrates are generally less 
sensitive to dioxins than mammals and birds.
    For assessing the potential for ecological risk in terrestrial 
ecosystems, soil criteria developed for 2,3,7,8-TCDD for the protection 
of mammals and birds were compared to model-estimated soil 
concentrations in terms of 2,3,7,8-TCDD TEQs. Because the more highly 
chlorinated 2,3,7,8 dibenzo(p)dioxin and dibenzofuran congeners are 
expected to bioaccumulate in prey species more slowly than 2,3,7,8-
TCDD, the potential for ecological risk is likely to be overstated. Our 
analysis indicates that, at baseline, less than one percent of the 
study areas surrounding hazardous waste combustors have the potential 
for ecological risk from dioxins in soil. Under today's rule, we 
project no exceedances of the ecotoxicological criteria for dioxins in 
soil. The soil ecotoxicological criterion for dioxins is derived from 
studies of reproductive and developmental effects in mammals. Potential 
impacts to terrestrial plant and soil communities could not be 
evaluated due to a lack of sufficient ecological toxicity data. 
However, vertebrates such as mammals and birds are known to be more 
sensitive to dioxin exposure than invertebrates. Therefore, we consider 
the potential for risk to invertebrate receptors to be low.
B. Mercury
    The ecological assessment of mercury is based on water quality 
criteria for the protection of wildlife that were developed for the 
Mercury Study Report to Congress. The assessment used the lowest of the 
available water quality criteria for individual fish-eating avian and 
mammalian wildlife species. The frequency distribution of ecological 
hazard quotients for total mercury indicates the potential for adverse 
ecological effects for cement kilns. Our analysis indicates that, for 
cement kilns, exceedances of the ecotoxicological criteria for total 
mercury may occur over 40 percent of study area surface waters at 
baseline. Above a hazard quotient of 1, the frequency of exceedances 
drops off quickly, with hazard quotients above 2 occurring at a 
frequency of 1 percent. The ecological hazard quotients remain 
essentially unchanged under today's rule. However, we project no 
exceedances of the ecotoxicological criteria for methyl mercury. 
Because methyl mercury is the form of mercury that is of greatest 
concern for fish-eating mammals and birds, the lack of exceedances 
suggests that the potential for ecological effects is relatively low. 
Our analysis also suggests relatively low potential for ecological 
effects for incinerators and lightweight aggregate kilns. Although our 
analysis indicates that exceedances of the ecotoxicological criteria 
for total mercury may occur over 22 percent of study area surface 
waters for lightweight aggregate kilns and 6 percent for incinerators 
at baseline, these are reduced to no exceedances and less than 1 
percent, respectively, under today's rule. Moreover, we project no 
exceedances of the ecotoxicological criteria for methyl mercury. The 
significance of these results must be judged in the context of the 
considerable uncertainties related to the fate and transport of mercury 
in the environment, as discussed elsewhere in today's notice, the 
presence of background levels of mercury, and the level of protection 
afforded by the underlying ecotoxicological criteria.
    For soils, our analysis indicates that less than one percent of the 
study areas surrounding hazardous waste combustors have the potential 
for ecological risk at baseline. Under today's rule, we project no 
exceedances of the ecotoxicological criteria for mercury for 
incinerators and lightweight aggregate kilns. For cement kilns, we 
project exceedances at a frequency of much less than one percent. The 
soil ecotoxicological criterion for mercury is derived from studies of 
the reproductive capacity of earthworms. Although earthworms serve a 
vital function in the soil community, given the redundancy and 
abundance of soil organisms and the low frequency of exceedances, we 
believe that adverse impacts to the terrestrial ecosystem, including 
higher trophic levels such as terrestrial mammals, are unlikely.
    As a screening level analysis, the ecological assessment is subject 
to a number of limitations. The analysis assumes the occurrence of the 
ecological receptors on which the ecotoxicological criteria are based 
in all modeled sectors and water bodies. Although the ecological 
receptors included in the analysis are commonly occurring species, they 
may not be present in the same locations at which exceedances are 
predicted due to a lack of suitable habitat or other factors. 
Furthermore, the range of predator and prey species may exceed the 
spatial extent of the estimated exceedances. Many primary and secondary 
consumers are opportunistic feeders with substantial variability in 
both the type of food items consumed as well as the seasonal patterns 
of feeding and foraging. These behaviors can be expected to moderate 
exposures to chemical contaminants and reduce the potential for risk. 
On the other hand, gaps exist in the ecotoxicological data base such 
that not all combinations of chemical constituents and ecological 
receptors could be evaluated. In addition, media concentrations could 
not be estimated for all habitats that may be important to ecological 
receptors, such as wetlands. Also, our analysis did not consider the 
possible impact of background concentrations. Therefore, although as a 
screening level analysis the ecological assessment has a tendency 
toward conservatism, we cannot say for certain that no potential exists 
for ecological risks that fall beyond the scope of the assessment.

Part Eight: Analytical and Regulatory Requirements

I. Executive Order 12866: Regulatory Planning and Review (58 FR 51735)

Is This a Significant Regulatory Action?
    Under Executive Order 12866 (58 FR 51735, October 4, 1993), we must 
determine whether a regulatory action is ``significant'' and, 
therefore, subject to OMB review and the requirements of the Executive 
Order. The Order defines ``significant regulatory action'' as one that 
is likely to result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more, 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or state, local, or tribal governments or 
communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlement, grants, 
user fees, or loan programs or the rights and obligations of recipients 
thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
this Executive Order.
    Under the terms of Executive Order 12866, we have reviewed today's 
rule and determined that it does not represent an ``economically 
significant'' regulatory action, as defined under point one above. The 
aggregate annualized social costs for this rule are under $100 million 
(ranging from $50 to $63 million for the final standards). However, it 
has been determined that this rule is a ``significant regulatory 
action'' because it may raise novel legal or policy issues (point four 
above). As such, this action was submitted to OMB for review. Changes 
made in response to OMB suggestions or recommendations will be 
documented in the public record.

[[Page 53010]]

    We have prepared economic support materials for today's final 
action. These documents are entitled: Assessment of the Potential 
Costs, Benefits, and Other Impacts of the Hazardous Waste Combustion 
MACT Standards--Final Rule, and, Addendum To The Assessment of the 
Potential Costs, Benefits, and Other Impacts of the Hazardous Waste 
Combustion MACT Standards--Final Rule. The Addendum and Assessment 
documents were designed to adhere to analytical requirements 
established under the Executive Order, and corresponding Agency and OMB 
guidance; subject to data, analytical, and resource limitations.
    This part of the Preamble is organized as follows: I. Executive 
Order 12866 (as addressed above), II. What Activities have Led to 
Today's Rule?--presenting a summary of the analytical methodology and 
findings from the 1996 RIA for the proposed action, and, a summary of 
substantive peer review and public stakeholder comments on this 
document, with Agency responses, III. Why is Today's Rule Needed?--
justifying the need for Federal intervention, IV. What Were The 
Regulatory Options?--presenting a brief discussion of the scope of 
alternative regulatory options examined, V. What Are the Potential 
Costs and Benefits of Today's Rule?--summarizing methodology and 
findings from the final Assessment document, VI. What Considerations 
Were Given to Issues Like Equity and Children's Health?, VII. Is 
Today's Rule Cost-Effective?, VIII. How Do the Costs of Today's Rule 
Compare to the Benefits?, IX. What Consideration Was Given to Small 
Businesses? X. Were Derived Air Quality and Non-Air Impacts Considered? 
XI. Is Today's Rule Subject to Congressional Review?, XII. How is the 
Paperwork Reduction Act Considered in Today's Rule?, XIII. Was the 
National Technology Transfer and Advancement Act Considered?, and, XIV. 
Were Tribal Government Issues Considered? (Executive Order 13084).
    The RCRA docket established for today's final rulemaking maintains 
a copy of the complete final Assessment and Addendum documents for 
public review. Readers interested in these economic support materials 
are strongly encouraged to read both documents to ensure full 
understanding of the methodology, data, findings, and limitations of 
the analysis.

II. What Activities Have Led to Today's Rule?

    In May of 1993, we introduced a draft Waste Minimization and 
Combustion Strategy designed to reduce reliance on the combustion of 
hazardous waste and encourage reduced generation of these wastes. Among 
the key objectives of the strategy was the reduction of health and 
ecological risks posed by the combustion of hazardous wastes. As part 
of this strategy, we initiated the development of MACT emissions 
standards for hazardous waste combustion facilities.
    On April 19, 1996, we published the proposal, which included 
revisions to standards for hazardous waste incinerators and hazardous 
waste burning cement kilns and lightweight aggregate kilns. These 
proposed MACT standards were designed to address a variety of hazardous 
air pollutants, including dioxins/furans, mercury, semivolatile and low 
volatile metals, and chlorine. We also proposed to use emissions of 
carbon monoxide and hydrocarbons as surrogates for products of 
incomplete combustion.
A. What Analyses Were Completed for the Proposal?
    We completed an economic analysis in support of the proposal. This 
Regulatory Impact Assessment (RIA), examined and compared the costs and 
benefits of the proposed standards, as required under Executive Order 
12866. Industry economic impacts, environmental justice, waste 
minimization incentives, and other impacts were also examined. This RIA 
also fulfilled the requirements of the Regulatory Flexibility Act by 
evaluating the effects of regulations on small entities. This document, 
Regulatory Impact Assessment for Proposed Hazardous Waste Combustion 
MACT Standards (November 13, 1995), Appendices (November 13, 1995), and 
two Addenda (November 13, 1995 and February 12, 1996) are available in 
the docket established for the proposed action.
    Throughout the development of the proposal, we considered many 
alternative regulatory options. A full discussion of the methodology 
and findings of all options considered is in the Regulatory Impact 
Assessment (RIA). Only the floor option and our preferred option (i.e., 
the floor option and beyond-the-floor options for selected hazardous 
air pollutants) are discussed in this summary.
1. Costs
    To develop industry compliance cost estimates, we categorized or 
modeled combustion units based on source category and size and 
estimated engineering costs for the air pollution control devices 
needed to achieve the proposed standards. Based on current emissions 
and air pollution control device information, we developed assumptions 
regarding the type of upgrades that units would require. This ``model 
plants'' engineering cost analysis was used because our data were 
limited.
    Total annual compliance cost estimates for the floor option and the 
beyond-the-floor standards ranged from $93 million to $136 million, 
respectively, beyond the baseline. For the floor option, on-site 
incinerators represented 55 percent of total nationwide costs, cement 
kilns represented 29 percent, commercial incinerators represented 14 
percent, and lightweight aggregate kilns represented 2 percent. Of the 
total beyond-the-floor costs, on-site incinerators represented 50 
percent, cement kilns represented 32 percent, commercial incinerators 
represented 15 percent, and lightweight aggregate kilns represented 3 
percent. For the incremental impacts of going from the floor to beyond-
the-floor, lightweight aggregate kilns were projected to experience a 
100 percent increase in compliance costs, cement kilns would experience 
a 63 percent increase, commercial incinerators and on'site 
incinerators, at 54 and 34 percent, respectively. Overall, compliance 
costs associated with the proposed action were projected to result in 
significant economic impacts to the combustion industry.
    The RIA also examined average total annual compliance costs per 
combustion unit. This indicator was designed to assess the relative 
impact of the rule on each facility type in the combustion universe. 
Findings projected that cement kilns were likely to incur the greatest 
average incremental cost per unit, totaling $770,000 annually at the 
floor and $1.1 million annually for the proposed beyond-the-floor 
standards. The costs for LWAKs ranged from $490,000 to $825,000. The 
costs for on-site incinerators ranged from $340,000 to $486,000. The 
costs for commercial incinerators ranged from $493,000 to $730,000. 
These costs assume no market exits. Once market exit occurs, average 
per unit costs may be significantly lower, particularly for on-site 
incinerators.
    The analysis also examined the floor and proposed beyond-the-floor 
impacts on a per ton basis. In the baseline, average prices charged to 
burn hazardous waste were estimated to be $178 per ton for cement 
kilns, $188 per ton for lightweight aggregate kilns, $646 per ton for 
commercial incinerators, and $580 per ton for on-site incinerators 
(approximate internal transfer price).

[[Page 53011]]

Baseline burn costs (before consolidation) for these facilities were 
found to average $104 per ton for cement kilns, $194 per ton for 
lightweight aggregate kilns, $806 per ton for commercial incinerators, 
and $28,460 per ton for on-site incinerators. 350 
Incremental compliance costs at the floor and proposed BTF levels were 
estimated to be $23 to $31 per ton for commercial incinerators, $40 to 
$50 per ton for cement kilns, $39 to $56 per ton for lightweight 
aggregate kilns, and $47 to $57 per ton for on-site incinerators.
---------------------------------------------------------------------------

    \350\ Baseline costs were calculated by identifying all costs of 
hazardous waste burning. For commercial incinerators and on-site 
incinerators, all costs of construction, operation and maintenance 
are included. This also includes RCRA permits and existing air 
pollution control devices. The costs for on-site burners are 
extremely high because the costs are distributed across the small 
amount of hazardous waste burned. For cement kilns and lightweight 
aggregate kilns, only the incremental costs of with burning 
hazardous waste are included (e.g., permits). The cost of the actual 
units (which are primarily for producing cement or aggregate) are 
not included in the baseline.
---------------------------------------------------------------------------

    From comparison of these prices and baseline burn costs, some high-
cost facilities, especially commercial and on-site incinerators, 
appeared to be burning below break-even levels. The incremental 
compliance costs of the proposal would make these facilities even less 
competitive. The RIA estimated that, of the facilities which are 
currently burning hazardous waste, three cement kilns, two lightweight 
aggregate kilns, six commercial incinerators, and eighty-two on-site 
incinerators would likely stop burning hazardous waste over the long 
term. These were incremental to projected baseline market exits 
estimated at the time of proposal. Most of the facilities that exit the 
market were ones that burned smaller amounts of hazardous waste.
    We also conducted a generalized cost effectiveness analysis for the 
proposal. We found that the cost per hazardous air pollutant is often 
difficult to estimate because the air pollution control devices often 
control more than one pollutant. Therefore, it was not feasible to 
estimate precise costs per pollutant. Once the compliance expenditures 
had been estimated, the total mass emission reduction achieved when 
facilities comply with the standards option was estimated. The total 
incremental cost per incremental reduction in pollutant emissions was 
then estimated. Considering all facilities together, dioxin, mercury, 
and metals costs per unit reduction are quite high because small 
amounts of the dioxin and metals are released into the environment. For 
other pollutants, expenditures per ton are much lower. Please refer to 
the November 13, 1995 draft RIA for a complete discussion of the 
methodology and findings.
2. Benefits
    Our evaluation showed that background levels of dioxin in beef, 
milk, pork, chicken, and eggs were approximately 0.50, 0.07, 0.30, 
0.20, and 0.10 parts per trillion fresh weight, respectively, on a 
toxicity equivalent (TEQ) basis. These background levels and 
information on food consumption were then used to estimate dietary 
intake in the general population. That estimate was 120 picograms TEQ 
per day. We also collected background data on dioxins in fish, taken 
from 388 locations nationwide. At 89 percent of the locations, fish 
contained detectable levels of at least two of the dioxin and furan 
compounds for which analyses were conducted. We then estimated total 
dioxin emissions from hazardous waste combustors at 0.94 kg TEQ per 
year. This represented about 9 percent of total anthropogenic emissions 
of dioxins in the U.S. at the time. The dioxin estimates have been 
revised since then.
    While no one-to-one relationship between emissions and risk exists, 
it was inferred that hazardous waste-burning sources were likely to 
contribute significantly to dioxin levels in foods. In the proposal, we 
estimated that these dioxin emissions would be reduced to 0.07 kg TEQ 
per year at the floor levels and to 0.01 kg TEQ per year at the beyond 
the floor levels. We estimated this to result in decreases of 
approximately 8 and 9 percent in total estimated anthropogenic U.S. 
emissions, respectively. Our position at proposal was that reductions 
in these emissions, in conjunction with reductions from other dioxin-
emitting sources, would help reduce dioxin levels in foods over time 
and, therefore, reduce the likelihood of adverse health effects, 
including cancer.
    Mercury is a concern in both occupational and environmental 
settings. Human exposures to methyl mercury occur primarily from 
ingestion of fish. Mercury contamination results in routine fish 
consumption bans or advisories in over two thirds of the States. At the 
proposal, we estimated a safe exposure level to methyl mercury (the 
reference dose) at 0.0001 mg per kg per day. We collected data on 
chemical residues in fish from 388 locations nationwide and found that 
fish contained detectable levels of mercury at 92 percent of the 
locations. Similar results have been obtained in other studies, 
strongly suggesting that long-range atmospheric transport and 
deposition of anthropogenic emissions is occurring. Our research found 
that, for persons who eat significant amounts of freshwater fish, 
exposures to mercury may be significant compared to the threshold at 
which effects may occur in susceptible individuals.
    Our estimates for the proposal indicated that hazardous waste 
combustors emitted a total of 10.1 Mg of mercury per year, representing 
about 4 percent of the U.S. anthropogenic total. Implementation of the 
floor levels were estimated to reduce mercury emissions from all 
hazardous waste-burning sources to 3.3 Mg per year. The proposed 
beyond-the-floor levels would drop this to an estimated 2.0 Mg per 
year. Such reductions were estimated to lower total anthropogenic U.S. 
emissions by approximately 3 percent. Reductions in these mercury 
emissions, in conjunction with the Agency's efforts to reduce emissions 
from other mercury-emitting sources, would help diminish mercury levels 
in fish over time and, therefore, reduce the likelihood of adverse 
health effects occurring in fish-consuming populations.
    Other benefits we investigated for the proposal included ecological 
benefits, property value benefits, soiling and material damage, 
aesthetic damages, and recreational and commercial fishing impacts. 
Overall, the analysis of the ecological risk suggested that water 
quality criteria may be exceeded only in small watersheds located near 
waste combustion facilities. Furthermore, such exceedances would occur 
only when assuming very high emissions. The preliminary analysis for 
the proposal indicated that property value impacts may be very 
significant because of emission reductions from hazardous waste 
combustion facilities. A detailed review of this analysis, as well as 
other benefits (e.g., avoided clean-up as result of reduced particulate 
matter releases), is presented in chapter 5 of the November 13, 1995 
Regulatory Impact Assessment.
3. Other Regulatory Issues
    We also examined other issues associated with the proposal. These 
included environmental justice, unfunded federal mandates, regulatory 
takings, and waste minimization.
    a. Environmental Justice. We completed an analysis of demographic 
characteristics of populations near cement plants and commercial 
hazardous waste incinerators and compared them to county and state 
populations. This analysis focused on spatial relationships between 
these

[[Page 53012]]

facilities and the adjacent minority and low income populations. The 
study did not describe the actual health status of these populations 
nor how their health might be affected in proximity to hazardous waste 
facilities. Results indicated that 27 percent of all cement plants and 
37 percent of the sample of incinerators had minority percentages 
within a one mile radius which exceed the corresponding county minority 
percentages by more than five percentage points. Eighteen percent of 
all cement plants and 36 percent of the sample of incinerators had 
poverty percentages which exceed the county poverty percentages by more 
than five percentage points. Please see chapter seven of the November 
13, 1995 RIA for a full discussion of the environmental justice 
methodology and findings conducted for the proposal.
    b. Unfunded Federal Mandates. Our analysis of compliance with the 
Unfunded Mandates Reform Act (UMRA) of 1995 found that the proposal 
contained no State, local, tribal government, or private sector Federal 
mandates as defined under the regulatory provisions of Title II of 
UMRA. We concluded that the rule implements requirements specifically 
set forth by Congress, as stated in the CAA and RCRA. The proposed 
standards were not projected to result in mandated annualized costs of 
$100 million or more to any state, local, or tribal government. 
Furthermore, the proposed standards would not significantly or uniquely 
affect small governments.
    c. Regulatory Takings. We found no indication that the proposed 
MACT standards would be considered a taking, as defined by legislation 
being considered by Congress at the time. Property would not be 
physically invaded or taken for public use without the consent of the 
owner. Also, the proposed standards would not deprive property owners 
of economically beneficial or productive use of their property or 
reduce the property's value.
    d. Incentives for Waste Minimization and Pollution Prevention. We 
briefly examined the potential for waste minimization in the proposal. 
Preliminary results suggested that generators have a number of options 
for reducing or eliminating waste. To evaluate whether facilities would 
adopt applicable waste minimization measures, a simplified pay back 
analysis was used. Using information on per-facility capital costs for 
each technology, we estimated the time period required for the cost of 
the waste minimization measure to be returned in reduced combustion 
expenditures. Our assessment of waste minimization found that 
approximately 630,000 tons of waste may be amenable to waste 
minimization. For a complete description of the analysis please see the 
November 13, 1995 Regulatory Impact Assessment.
4. Small Entity Impacts
    The Regulatory Flexibility Act (RFA) of 1980 requires Federal 
agencies to consider impacts on small entities throughout the 
regulatory process. Section 603 of the RFA calls for an initial 
screening analysis to determine whether small entities will be 
adversely affected by the regulation. If affected small entities are 
identified, regulatory alternatives must be considered to mitigate the 
potential impacts. Small entities, as described by the Act, are only 
those ``businesses, organizations, and governmental jurisdictions 
subject to regulation.'' We used information from Dunn & Bradstreet, 
the American Business Directory, and other sources to identify small 
businesses. Based on the number of employees and annual sales 
information, we identified eleven firms which might be considered 
directly affected small entities. We found that directly affected small 
entities were unlikely to be significantly affected and that over one-
third of those that were considered small, while having a relatively 
small number of employees, had annual sales in excess of $50 million 
per year. Also, small entities impacted by the proposal were found to 
be those that burn very little waste and hence face very high cost per 
ton burned. These facilities were expected to discontinue burning 
hazardous waste rather than complying with the proposal. These costs of 
discontinuing waste burning would not be so high as to be a significant 
impact. Thus, we found that the proposal may, at most, have a minor 
impact on a limited number of affected small businesses.
B. What Major Comments Were Received on the Proposal RIA?
    The November 13, 1995 Regulatory Impact Assessment (RIA) received 
comment from many concerned stakeholders. We also conducted a formal 
peer review of the RIA. We appreciate all comments received and 
incorporated many of the suggestions into the final Assessment document 
to improve the analysis. A summary of the key issues presented by 
stakeholders and the peer reviewers is presented below, along with our 
responses. You are requested to review the complete documents: Comment 
Response Document--Addressing The Public Comments Received On: 
Regulatory Impact Assessment for Proposed Hazardous Waste Combustion 
MACT Standards, Draft, November 13, 1995, and, Peer Review Response 
Document--Addressing The Peer Review Received On: Regulatory Impact 
Assessment for Proposed Hazardous Waste Combustion MACT Standards, 
Draft, November 13, 1995. These documents, available in the RCRA docket 
established for today's action, present complete responses to all 
substantive comments received on the 1995 RIA.
1. Public Comments
    We received several general comments on the accuracy of the 
baseline and compliance costs applied in the RIA. Several commenters 
suggested that we revise baseline and compliance costs to improve their 
accuracy, which we did. Instead of using a model plant approach for 
assigning compliance and baseline costs to modeled combustion 
facilities, costs for today's rule have been estimated using combustion 
system-specific parameters including gas flow rate, baseline emissions, 
air pollution control devices currently in place, total chlorine in 
feed, stack moisture, and temperature at the inlet to the air pollution 
control device. These system-specific baseline and compliance costs 
allow for greater accuracy in estimating national costs and predicting 
which facilities are likely to stop burning hazardous waste. Also, the 
baseline costs include clinker production penalties at cement kilns and 
use updated incinerator capital costs, labor requirements, and ash 
disposal costs.
    Various commenters were concerned that the consolidation routine in 
the economic modeling was unrealistic. For the final economic 
assessment, we revised the consolidation routine to incorporate 
capacity constraints that affect the ability of combustion facilities 
to consolidate wastes into fewer systems at a given facility. Maximum 
capacity rates (tons per year) were derived by using the feed rates in 
OSW's database (pounds per year) and assuming 8,000 hours per year of 
operation. Wastes are assumed to be consolidated into fewer combustion 
systems at a single facility to the extent that the capacity 
constraints allow the systems to absorb the displaced hazardous wastes.
    Many commenters felt that the waste minimization analysis of the 
1995 RIA was unrealistic and overestimated gains. They suggested that 
the waste minimization analysis be improved to reflect other 
constraints faced by waste generators. For the 1999 Assessment, we 
conducted an expanded and significantly improved analysis of waste

[[Page 53013]]

minimization alternatives, using a more detailed decision framework for 
evaluating waste minimization investment decisions. This framework 
attempts to capture the full inventory of costs, savings, and revenues, 
including indirect, less tangible items typically omitted from waste 
minimization analysis, such as liability and corporate image. For each 
alternative that was identified as viable for currently combusted waste 
streams, cost curves were developed for a range of waste quantities, as 
cost varies by waste quantity. These cost curves were then used to 
determine whether a waste generator would shift from combustion to 
waste minimization alternatives as combustion prices rise.
    Some commenters suggested that we model waste markets to reflect 
segmentation across waste types, instead of simply applying different 
prices for kilns and incinerators. In response, we have developed a 
revised pricing approach that covers seven categories of waste types 
and prices. The economic model used for the 1999 Assessment 
incorporates these seven different waste types and prices. Waste 
management prices depend on several factors: Waste form (solid/liquid/
sludge), heat content, method of delivery (e.g., bulk versus drum), and 
contamination level (e.g., metals or chlorine content). In addition, 
regulatory constraints (e.g., prohibitions against burning certain 
types of wastes) and technical constraints (e.g., adverse effects of 
certain waste streams on cement product quality) also influence 
combustion prices. Although data limitations prevent the inclusion of 
all factors, the information on heat content and constituent 
concentrations from EPA's National Hazardous Waste Constituent Survey 
(NHWCS) allowed us to enhance the characterization of combusted waste.
    A few commenters indicated that the baseline costs of waste burning 
for cement kilns should include the shared joint costs of cement 
production. We do not include cement production costs in the costs of 
waste burning because they are not part of the incremental costs 
introduced by hazardous waste burning at kilns. We believe this 
assumption is appropriate, given that cement production is the 
principal activity of cement kilns that burn hazardous waste. 
Furthermore, that same kiln would be required in the production of 
cement regardless of hazardous waste combustion activities. We did, 
however, evaluate whether some of the more economical marginal kilns 
may be covering cement production costs with hazardous waste burning 
revenues. These findings are reported in the 1999 Assessment document.
    Some were concerned that shutdown costs and environmental risks 
associated with combustion facility closures were not accounted for in 
the 1995 economic analysis. We found that many of the facilities that 
are expected to close are those that are were operating significantly 
below capacity in the baseline. This suggests that such facilities may 
not have been fully recovering their capital costs and are likely to 
close, even in the absence of the MACT standards. Therefore, while 
closure is not costless, closure costs attributable directly to the 
MACT standards are likely to be relatively small. With regard to 
increased risks from transportation of hazardous wastes, the 
incremental health risks will be minimal since these facilities are 
burning small quantities of waste. In fact, we estimate that less than 
1.5 percent of the wastes currently burned at combustion facilities 
will be reallocated due to facility closure. Moreover, spills and other 
accidents caused by trucking hazardous waste (the most common means of 
shipment for hazardous materials) generally are considered low-
probability events, especially relative to the total number of 
accidents occurring within transportation overall.
    Some commenters felt that potential impacts on generators and fuel 
blenders were not adequately addressed. In the 1995 RIA, we considered 
these costs and determined that hazardous waste generators and fuel 
blenders would likely see price increases for combusted waste streams, 
though the magnitude of the price increase will depend on the type of 
waste and the non-combustion waste management alternatives available 
for that waste type. The price increase faced by generators was 
estimated at 10 percent of market prices.
    The major hazardous waste burning sectors frequently presented 
alternative views regarding various key waste burning issues. These 
included: Facility market exits, revenues, impacts resulting from waste 
feedrate modifications, impacts from alternative fuel usage, price 
impacts, and available practical capacity. We have reviewed and 
evaluated the substantiative information submitted by all concerned 
stakeholders and believe our final Assessment and Addendum documents 
reflect a fair and balanced representation of baseline conditions and 
post-rule incremental economic impacts.
2. Peer Review
    The peer reviewers suggested that we clarify the aims, objectives, 
and organizing principles for the 1995 RIA. They stated that, while the 
1995 RIA generally meets the requirements set forth by OMB's Guidance 
regarding the economic analysis of federal regulations under Executive 
Order 12866, the RIA would be substantially improved if it fully 
conformed with OMB's Guidance, especially with regard to organization 
and statement of objectives. For the 1999 Assessment, we have tried to 
restructure the document to be more in line with OMB's 1996 Guidance 
for conducting Economic Analysis of Federal Regulations Under Executive 
Order 12866. The 1999 Assessment includes the following elements in the 
first chapter to address concerns of the reviewers: the objectives of 
the Economic Assessment, the analytical requirements the document 
fulfills, the rationale for regulatory action, an examination of 
alternative regulatory options, the anticipated effect of the MACT 
standards, and the analytic approach and organization for the 
subsequent chapters.
    The peer reviewers also suggested that the compliance costs need to 
be clearly distinguished from social costs, as defined by the theory of 
applied welfare economics. For the 1999 Assessment, we have been 
careful to clarify the difference between compliance costs and social 
costs and explain how the rule will likely affect producers and 
consumers. The final Assessment explicitly lays out the economic 
framework for the social cost analysis and distinguishes these from 
compliance cost estimates. The hazardous waste combustion market is 
diverse, dynamic, and segmented. Because data are not adequate to 
support a full econometric analysis at this level of complexity, we 
have applied a simplified approach that brackets the welfare loss 
attributable to today's rule. This approach bounds potential economic 
welfare losses by considering two scenarios: (1) Compliance costs 
assuming no market adjustments (the upper bound) and (2) market 
adjusted compliance costs (the lower bound).
    The peer reviewers also suggested that the benefits analysis was 
not fully responsive to the requirements of Executive Order 12866. For 
the 1999 Assessment, we have applied results from an extensive multi-
pathway risk assessment to develop human health and ecological benefit 
estimates. For the human health analysis, benefits are estimated from 
cancer and noncancer

[[Page 53014]]

risk reductions. Cancer risk reduction estimates are monetized by 
applying the value of a statistical life (VSL) to the risk reduction 
expected to result from the MACT standards. Monetary values are 
assigned to noncancer benefits using a direct-cost approach which 
focuses on the expenditures averted by decreasing the occurrence of an 
illness or other health effect. Ecological benefits are also included 
in the 1999 Assessment.
    The peer reviewers suggested that easily burned waste streams would 
command lower prices and that this should be reflected in the economic 
modeling. They also indicated that certain combustion sectors may only 
handle these easy-to-burn waste types and that this should be reflected 
in baseline costs for these combustors. The pricing approach used in 
the 1999 Assessment assigns different prices to different types of 
wastes. Waste management prices depend on several factors, which 
include: waste form (solid/liquid/sludge), heat content, method of 
delivery (e.g., bulk versus drum), and contamination level (e.g., 
metals or chlorine content). In addition, regulatory constraints (e.g., 
prohibitions against burning certain types of wastes) and technical 
constraints (e.g., adverse effects of certain waste streams on cement 
product quality) also influence combustion prices. Although data 
limitations prevent us from accounting for all factors, the information 
on heat content and constituent concentrations from EPA's National 
Hazardous Waste Constituent Survey (NHWCS) allowed us to enhance the 
characterization of combusted waste. In addition to pricing 
refinements, the 1999 Assessment adjusts baseline costs to reflect 
differences in the performance and capabilities across combustion 
systems.
    The peer reviewers were also concerned that the 1995 RIA applied 
outdated data in the analysis. The most recent available data were used 
in the 1995 RIA. The 1999 Assessment, once again, applies the most 
recently available, and verified data.
    The peer reviewers suggested that fully-loaded cost-per-ton 
estimates should be provided for each waste minimization alternative so 
that these could be compared with combustion prices. For the 1999 
Assessment, we conducted an expanded and significantly improved 
analysis of waste minimization alternatives. This analysis used a more 
detailed decision framework for evaluating waste minimization 
investment decisions that captures the full inventory of costs, 
savings, and revenues, including indirect, less tangible items 
typically omitted from waste minimization analysis, such as liability 
and corporate image. For each viable waste minimization alternative for 
currently combusted waste streams, cost curves were developed for a 
range of waste quantities because cost varies by waste quantity. These 
cost curves were then used to determine whether a waste generator would 
shift from combustion to waste minimization alternatives as combustion 
prices rise.

III. Why Is Today's Rule Needed?

    Today's rule will reduce the level of several hazardous air 
pollutants, including dioxins and furans, mercury, semi-volatile and 
low volatile metals, and chlorine gas. Carbon monoxide, hydrocarbons, 
and particulate matter will also be reduced. Most hazardous waste 
combustion facilities are currently operating with some air pollution 
control devices in place. However, existing pollutants from these 
facilities are still emitted at levels found to result in risks to 
human health and the environment. Human exposure to these combustion 
air toxics occurs both directly and indirectly and leads to cancer, 
respiratory diseases, and possibly developmental abnormalities. A 
preliminary screening analysis suggests that ecosystems are also at 
risk from these air pollutants.
    The hazardous waste combustion industry operates in a dynamic 
market. Several combustion facilities and systems have closed or 
consolidated over the past several years and this trend is likely to 
continue. These closures and consolidations may lead to reduced air 
pollution, in the aggregate, from hazardous waste facilities. However, 
the ongoing demand for hazardous waste combustion services will 
ultimately result in a steady equilibrium as the market adjusts over 
the long-term. We therefore expect that air pollution problems from 
these facilities, and the corresponding threats to human health and 
ecological receptors, will continue if today's rule were not 
implemented.
    The market has generally failed to correct the air pollution 
problems resulting from the combustion of hazardous wastes. This has 
occurred for several reasons. First, there exists no natural market 
incentive for hazardous waste combustion facilities to incur additional 
costs implementing control measures because the individuals and 
entities who bear the negative human health and ecological impacts 
associated with these actions have no direct control over waste burning 
decisions. This may be referred to as an environmental externality, 
where the private industry costs of combustion do not fully reflect the 
human health and environmental costs of hazardous waste combustion. 
Second, the parties injured by the combusted pollutants are not likely 
to have the resources or technological expertise to seek compensation 
from the damaging entity (combustion facility) through legal or other 
means. Finally, emissions from hazardous waste combustion facilities 
directly affect a ``public good,'' the air. Improved air quality 
benefits human health and the environment. These benefits cannot be 
limited to just those who pay for reduced pollution. The absence of 
government intervention, therefore, will result in a free market that 
does not provide the socially optimal quantity and quality of public 
goods, such as air.
    We recognize the need for federal regulation as the optimal means 
of correcting market failures leading to the negative environmental 
externalities resulting from the combustion of hazardous waste. The 
complex nature of the pollutants, waste feeds, waste generators, and 
the diverse nature of the combustion market would limit the 
effectiveness of a non-regulatory approach such as taxes, fees, or an 
educational-outreach program. Furthermore, requirements for MACT 
standards under the Clean Air Act, as mandated by Congress, has 
compelled us to select today's regulatory approach.

IV. What Were the Regulatory Options?

    We carefully assembled and evaluated all data and relevant 
information acquired since the proposal. We considered several 
alternative MACT options since the proposal, ultimately leading to 
today's rule. Please refer to Part Four of this preamble for more 
detail on option development and the specific approach and methodology 
used in developing the final standards. This section of today's 
preamble briefly discusses and assesses the final regulatory levels and 
two primary options. The final regulatory levels, as discussed in Part 
Four, establish a combination of floor and beyond-the-floor standards 
for the pollutants of concern. Of the options analyzed, one addresses a 
floor only scenario and the other examines beyond-the-floor levels for 
dioxins/furans and mercury, based on activated carbon injection (ACI). 
The reader may wish to examine the Assessment document for a complete 
discussion of the analytical methodology, costs, benefits, and other 
projected impacts of today's rule and options. This Assessment document 
is available in the RCRA docket for today's rule.

[[Page 53015]]

V. What Are the Potential Costs and Benefits of Today's Rule?

A. Introduction
    The value of any regulatory policy is traditionally measured by the 
net change in social welfare that it generates. Our economic assessment 
for today's rule evaluates costs, benefits, economic impacts, and other 
impacts such as environmental justice, children's health, unfunded 
mandates, waste minimization incentives, and small entity impacts. To 
conduct this analysis, we examined the current combustion market and 
practices, developed and implemented a methodology for examining 
compliance and social costs, applied an economic model to analyze 
industry economic impacts, quantified (and, where possible, monetized) 
benefits, and followed appropriate guidelines and procedures for 
examining equity considerations, children's health, and other impacts. 
The data we used in this analysis were the most recently available at 
the time of the analysis. Data verification, relevance, and public 
disclosure issues prevented us from incorporating data from certain 
sources. Furthermore, because our data were limited, the estimated 
findings from these analyses should be viewed as national, not site 
specific impacts.
B. Combustion Market Overview
    The hazardous waste industry comprises three key segments: 
hazardous waste generators, fuel blenders and intermediaries, and 
hazardous waste incinerators. Hazardous waste is combusted at three 
main types of facilities: Commercial incinerators, on-site 
incinerators, and waste burning kilns (cement kilns and lightweight 
aggregate kilns). Commercial incinerators are generally larger in size 
and designed to manage virtually all types of solids, as well as liquid 
wastes. On-site incinerators are more often designed as liquid-
injection systems that handle liquids and pumpable solids. Waste 
burning kilns burn hazardous wastes to generate heat and power for 
their manufacturing processes.
    As of the date of our analysis, 172 combustion facilities are 
permitted to burn hazardous waste in the United States. On-site 
incinerators (private and government) represent 129 facilities (or 75 
percent of this total), commercial incinerators represent 20 
facilities, cement kilns represent 18 facilities, and lightweight 
aggregate kilns represent five facilities. A facility may have one or 
more combustion systems. Companies that generate large quantities of 
uniform hazardous wastes generally find it more economical and 
efficient to combust these wastes on-site using their own noncommercial 
systems. Commercial incineration facilities manage a wide range of 
waste streams generated in small to medium quantities by diverse 
industries. Cement kilns and lightweight aggregate kilns derive heat 
and energy by combining clean burning (solvents and organics) high-Btu 
liquid hazardous wastes with conventional fuels. The EPA Biennial 
Reporting System (BRS) reports a total demand for all combusted 
hazardous waste, across all three types of facilities, at nearly 3.3 
million tons in 1995.
    Most of the waste managed by combustion comes from a relatively 
narrow set of industries. The entire chemical industry in 1995 
generated 74 percent of all combusted waste. Within this sector, the 
organic chemicals subsector was the largest source of waste sent to 
combustion, providing about 32 percent of all combusted waste. The 
pesticide and agricultural chemical industry generated 12 percent of 
the total. No other single sector generated more than 10 percent of the 
total.
    Regulatory requirements, liability concerns, and economics 
influence the demand for combustion services. Regulatory forces 
influence the demand for combustion by mandating certain hazardous 
waste treatment standards (land disposal restriction requirements, 
etc.). Liability concerns of waste generators affect combustion demand 
because combustion, by destroying organic wastes, greatly reduces the 
risk of future environmental problems. Finally, if alternative waste 
management options are more expensive, hazardous waste generators will 
likely choose to send their wastes to combustion facilities in order to 
increase their overall profitability.
    Throughout much of the 1980s, hazardous waste combustors enjoyed a 
strong competitive position and generally maintained a high level of 
profitability. During this period, EPA regulations requiring combustion 
greatly expanded the waste tonnage for this market. In addition, 
federal permitting requirements, as well as powerful local opposition 
to siting of new incinerators, constrained the entry of new combustion 
systems. As a result, combustion prices rose steadily, ultimately 
reaching record levels in 1987. The high profits of the late 1980s 
induced many firms to enter the market, in spite of the difficulties 
and delays anticipated in the permitting and siting process. Hazardous 
waste markets have changed significantly since the late 1980s. In the 
early 1990s, substantial overcapacity resulted in fierce competition, 
declining prices, poor financial performance, numerous project 
cancellations, and some facility closures. Since the mid 1990s, several 
additional combustion facilities have closed, while many of those that 
have remained open have consolidated their operations. There still 
remains significant overcapacity throughout the hazardous waste 
combustion industry.
C. Baseline Specification
    Proper and consistent baseline specification is vital to the 
accurate assessment of incremental costs, benefits, and other economic 
impacts associated with today's rule. The baseline essentially 
describes the world absent today's rule. The incremental impacts of 
today's rule are evaluated by predicting post MACT compliance responses 
with respect to the baseline. The baseline, as applied in this 
analysis, is the point at which today's rule is promulgated. We 
recognize that the baseline should not simply describe a point in time, 
but rather should describe the state of the world over time, absent 
today's rule. The Assessment describes the data sources used in 
specifying the baseline and examines how each of these factors are 
likely to change over time in the absence of today's rule. Finally, 
because this analysis precedes final rule promulgation, data sources 
used to determine the baseline will necessarily predate the point of 
rule promulgation. A full discussion of baseline specification is 
presented in the Assessment document for today's rule.
D. Analytical Methodology and Findings--Engineering Compliance Cost 
Analysis
    The total compliance costs for existing hazardous waste combustion 
facilities are developed using engineering models that assign pollution 
control measures and costs to each modeled combustion system. The 
engineering model also incorporates other compliance costs, such as 
monitoring requirements, permit modifications, sampling and analyses, 
and other recordkeeping and reporting requirements. We applied the same 
basic approach in developing compliance costs for new sources as was 
used for existing sources. Please see the Assessment document for a 
complete discussion of the analytical methodology applied for existing 
and new facilities.
    Compliance costs presented in this section are based on a static 
analysis assuming no market adjustments.

[[Page 53016]]

Results from this static analysis should therefore be considered 
``high-end'' estimates. The engineering compliance cost analysis 
reveals that each combustion system will likely comply with the final 
standards through a different combination of pollution control 
measures. This is likely to result in widely diverse per system 
compliance costs across combustion sectors. The average annualized per 
system costs, across all sectors, are projected to range from about 
$0.16 to $0.72 million for compliance with the final standards. Per 
system costs at the floor are estimated to range from $0.16 to $0.68 
million, while these costs under the beyond-the-floor activated carbon 
injection (ACI) option would range from $0.36 to $0.99 million. Cement 
kilns were generally found to experience the highest per system 
compliance costs, while the commercial and on-site incinerators would 
generally experience the lowest per system costs. The compliance costs 
per ton of hazardous waste burned are projected to increase from 31 to 
41 percent for cement kilns and about 35 percent for lightweight 
aggregate kilns. The increase for commercial incinerators is estimated 
at 20 percent of the baseline burn costs. The regulated community is 
also likely to experience some cost savings as a result of the 
streamlined administrative procedures established through today's final 
rule.
    The compliance cost analysis contains a variety of uncertainties. 
The most significant include: The limited availability of emissions 
data upon which engineering controls are based, lack of baseline air 
pollution control device data for a number of facilities, and the 
difficulty in determining the extent to which feed control may be used 
as a feasible alternative method of compliance. While uncertainties are 
acknowledged, we do not believe that the above data limitations 
significantly bias the results either upward or downward.
    In addition to costs incurred by the private sector, today's rule 
is also likely to result in incremental costs and savings to government 
regulatory entities at different levels as they administer and enforce 
the new emissions standards and related requirements. EPA Regional 
offices, state agencies, as well as some local agencies may incur some 
combination of incremental costs associated with permitting. 
Modifications of the permitting process related to Clean Air Act 
provisions could cost governmental entities, nationwide, approximately 
$330,000 per year. Potential government activities could also include 
the state rulemaking efforts necessary for agencies to modify their 
RCRA permitting processes as part of the ``Fast-Track'' provisions. 
State rulemakings and authorization of the modified procedures could 
cost states between $500,000 and $700,000, nationwide. Streamlined RCRA 
permit modification procedures may also result in aggregate savings 
ranging from $0.4 to $2.1 million. Overall economic impacts on 
particular governmental regulatory entities will depend on a variety of 
factors that are difficult to characterize with precision. Furthermore, 
economic impacts associated with governmental activities will differ in 
the way in which a particular governmental entity may choose to 
implement the requirements.
E. Analytical Methodology and Findings--Social Cost Analysis
    We examined social cost impacts potentially associated with today's 
rule. Total social costs include the value of resources used to comply 
with the standards by the private sector, the value of resources used 
to administer the regulation by the government, and the value of output 
lost due to shifts of resources to less productive uses. To evaluate 
these shifts in resources and changes in output requires predicting 
changes in behavior by all affected parties in response to the 
regulation, including responses of directly-affected entities, as well 
as indirectly-affected private parties.
    For this analysis, social costs are grouped into two categories: 
economic welfare (changes in consumer and producer surplus), and 
government administrative costs. The economic welfare analysis 
conducted for today's rule uses a simplified partial equilibrium 
approach to estimate social costs. In this analysis, changes in 
economic welfare are measured by summing the changes in consumer and 
producer surplus. This simplified approach bounds potential economic 
welfare losses associated with the rule by considering two scenarios: 
Compliance costs assuming no market adjustments, and market adjusted 
compliance costs.
    Social costs presented in this section assume market adjustments. 
Under this scenario, increased compliance costs are examined in the 
context of likely incentives combustion facilities would have to 
continue burning hazardous wastes and the competitive balance in 
different combustion sectors. Furthermore, combustion facilities are 
likely to try to recover these increased costs by charging higher 
prices to generators and fuel blenders. This scenario estimates market 
adjusted compliance costs by assessing baseline profitability, 
profitability post-rule using different price increase scenarios, and 
waste management alternatives in order to help predict combustion price 
increases.
    Overall, the difference in aggregate compliance costs for all 
sectors of the existing regulated community to meet any of the examined 
scenarios is not substantial. Total annualized market adjusted costs 
for all sectors are estimated to range from $44 to $50 million under 
the floor option. Under the beyond-the-floor (ACI) option, these costs 
are estimated to range from $98 to $107 million. For all sectors to 
meet the final standards, our best estimate of total annualized costs 
ranges from $50 to $63 million, depending upon level of price pass-
through. All cost estimates are incremental to the baseline. These 
estimates, however, are not incremental to any mutual requirements 
potentially associated with cement kilns meeting standards established 
under the nonhazardous waste burner cement kiln rule.
    Cement kilns ($17-24 million) and private on-site incinerators 
($20-24 million) make up about 76 percent of aggregate national costs 
under the final standards. For cement kilns, this is due primarily to 
the high costs per system. For private on-site incinerators, the high 
costs are primarily due to the large number of combustion systems. 
Total costs are less for commercial incinerators ($5-6 million, or 10 
percent) because of lower costs per system relative to cement kilns and 
due to the limited number of commercial units relative to on-site 
incinerators. Lightweight aggregate kilns ($3 million) represent about 
5 to 6 percent of the total costs, due primarily to the limited number 
of units. Government on-site units make up the remainder.
F. Analytical Methodology and Findings--Economic Impact Analysis
    Various market adjustments are expected in response to the 
increased costs of hazardous waste combustion associated with today's 
rule. Economic impacts may be measured through numerous factors. This 
analysis examines market exit estimates, waste reallocations, 
employment impacts, combustion price increases, industry impacts, and 
the multirule or joint impacts analysis. Economic impacts presented in 
this section are distinct from the social costs analysis, which 
represents only the monetary value of market disturbances.

[[Page 53017]]

1. Market Exit Estimates
    The hazardous waste combustion industry operates in a dynamic 
market, with a number of systems/facilities projected to exit the 
hazardous waste burning market under baseline conditions (see Section 
V. B of this Part). As a result, this analysis presents market exit 
estimates expected to result under the baseline, as well as from 
today's rule. This approach is developed in an effort to present a more 
accurate estimate of ``real-world'' incremental impacts resulting from 
the final standards. Market exit estimates are derived from a breakeven 
analysis designed to determine system and facility viability. This 
analysis is subject to several assumptions, including: engineering cost 
data on the baseline costs of waste burning, cost estimates for 
pollution control devices, prices for combustion services, and 
assumptions about the waste quantities burned at these facilities. It 
is important to note that, for most sectors, exiting the hazardous 
waste combustion market is not equivalent to closing a plant. (Actual 
plant closure would only be expected in the case of an exit from the 
hazardous waste combustion market of a commercial incinerator closing 
all its systems.)
    A relatively small percentage of facilities (including no 
lightweight aggregate kilns) are projected to stop burning hazardous 
waste as a result of the incremental requirements associated with 
today's rule. Those facilities that do exit were found to be marginally 
profitable in the baseline, burning low quantities of hazardous waste. 
The economic model post-consolidation results indicate that, in 
response to today's rule, the following number of combustion facilities 
are expected to cease burning hazardous waste in the short term: Cement 
kilns, zero out of 18 facilities; lightweight aggregate kilns, zero out 
of five facilities; commercial incinerators, zero out of 20 facilities; 
and private on-site incinerators, 16 out of 111 facilities.
    The number of anticipated market exits increases in the long term 
due to the necessity of recovering the capital costs of combustion. 
However, because this also holds true in the baseline, an increased 
number of projected long-term baseline market exits may, in some cases, 
actually decrease the number of incremental long-term exits. There 
remain zero incremental market exits for LWAKs and commercial 
incinerators over the long-term. Incremental market exits for cement 
kilns, however, increase from zero in the short-term to up to two over 
the long-term. Incremental market exits for private on-site 
incinerators decline from 16 in the short-term to 13 over the long-
term. This is due to a 62 percent increase in baseline market exits 
from the short-term to the long-term.
2. Quantity of Waste Reallocated
    Combustion systems that can no longer cover costs (i.e., those 
below the dynamic breakeven quantity) are projected to stop burning 
hazardous waste. Hazardous wastes from these systems will likely be 
reallocated to other viable combustion systems at the same facility if 
there is sufficient capacity, alternative combustion facilities that 
continue burning, or waste management alternatives (e.g., solvent 
reclamation). Because combustion is likely to remain the lowest cost 
option, we expect most reallocated wastes will continue to be managed 
at combustion facilities.
    The economic model indicates that, in response to today's rule, 
between 14,000 to 42,000 tons of currently burned hazardous waste could 
be reallocated to other facilities or waste management alternatives. 
This estimate represents between 0.4 and 1.3 percent of the total 
quantity of combusted hazardous wastes and is incremental to projected 
long-term baseline reallocations of approximately 100,000 tons. 
Currently, there is more than adequate capacity within the remaining 
sources of the combustion market to accommodate this reallocated waste, 
even at the high-end estimate.
3. Employment Impacts
    Today's rule is likely to cause employment shifts across all of the 
hazardous waste combustion sectors. These shifts will occur as specific 
combustion facilities find it no longer economically feasible to keep 
all of their systems running, or to stay in the hazardous waste market 
at all. When this occurs, workers at these locations may lose their 
jobs. At the same time, the rule may result in employment gains, as new 
purchases of pollution control equipment stimulate additional hiring in 
the pollution control manufacturing sector and as additional staff are 
required at combustion facilities for various compliance activities.
    a. Employment Impacts--Losses. Primary employment losses in the 
combustion industry are likely to occur when combustion systems 
consolidate the waste they are burning into fewer systems or when a 
facility exits the hazardous waste combustion market altogether. 
Operation and maintenance labor hours are expected to be reduced for 
each system that stops burning hazardous waste. For each facility that 
completely exits the market, employment losses will likely also include 
supervisory and administrative labor.
    Total incremental employment dislocations potentially resulting 
from the final standards range from approximately 100 to 230 full-time-
equivalent (FTE) jobs under the floor and the recommended options. 
Under the beyond-the-floor (ACI) option the high-end estimate of 
employment dislocations increases by almost 9 percent to approximately 
250 FTEs. Among the different sectors, on-site incinerators are 
responsible for most of the total estimated number of job losses. Their 
significant share of the losses is a function of both the large number 
of on-site incinerators in the universe as well as the relatively high 
number of expected exits within this sector. Cement kilns are 
responsible for the second largest number of expected employment losses 
due to the number of systems that consolidate waste-burning at these 
facilities.
    b. Employment Impacts--Gains. In addition to employment losses, 
today's rule will also lead to job gains as firms invest to comply with 
the various requirements of the rule and add additional operation and 
maintenance personnel for the new pollution equipment and other 
compliance activities, such as new reporting and record keeping 
requirements.
    The total annual employment gains (without particulate matter 
continuous emission monitors) associated with the floor and recommended 
final standards are approximately 300 FTEs. The beyond-the-floor (ACI) 
option may increase the high-end employment gain estimate to as much as 
620 FTEs. About one-third to one-half of all estimated job gains are 
projected to occur in the pollution control equipment industry. The 
remaining job gains will occur at the combustion facilities as 
additional personnel are hired for operation and maintenance and 
permitting requirements.
    While it may appear that this analysis suggests overall net job 
creation under particular options and within particular combustion 
sectors, such a conclusion would be inappropriate. Because the gains 
and losses occur in different sectors of the economy, they should not 
be added together. Doing so would mask important distributional effects 
of the rule. In addition, the employment gain estimates reflect within 
sector impacts only and therefore do not account for job displacement 
across sectors as

[[Page 53018]]

investment funds are diverted from other areas of the larger economy.
4. Combustion Price Increases
    All combustion facilities that remain in operation will experience 
increased operational costs under today's rule. To protect their 
profits, each facility will have an incentive to pass these increased 
costs on to their customers (generators and blenders) in the form of 
higher combustion prices. Generators and blenders are expected to pay 
these higher prices unless they have less expensive waste management 
alternatives.
    Under the theory of market price adjustments, as applied in the 
economic model, waste would be sent to the least expensive alternatives 
first, all else being equal. At the same time, prices would rise to the 
point at which all demand for waste management is met. In theory, the 
last tons would be managed by substituting non-combustion or waste 
minimization alternatives. The most efficient waste management 
substitute for these wastes would cap price increases, resulting in a 
new market price. Combustion facilities, in turn, would each set their 
prices at this market price in order to maximize profits. Less 
efficient waste management scenarios may earn just enough to stay in 
business over the short term, but would not recover capital costs. 
Combustion systems operating above the market price would lower their 
prices or exit the market. In reality, the hazardous waste combustion 
marketplace is very complex, and the determination of an adjusted 
market price would be an ongoing process affected by numerous factors, 
including price differentials among regions, waste stream types, and 
generators.
    Available economic data on the cost of waste management 
alternatives for combusted hazardous waste, including source reduction 
and other waste minimization options, are not precise enough to allow 
for an accurate estimate of the maximum price increase that combustors 
may pass through to generators and fuel blenders. However, available 
data do indicate that the demand for hazardous waste combustion is 
relatively inelastic and that combustion facilities are likely to pass 
through approximately 75 percent of compliance costs in the least-cost 
sector. High-cost sectors, however, may pass through less than the 75 
percent estimate. We also analyzed a 25 percent price pass through 
scenario. Under the recommended final standards, the weighted average 
combustion price per ton is projected to increase anywhere from about 
0.5 to 11 percent, depending upon sector and scenario. Prices were 
found to increase by as much as 25 percent under the beyond-the-floor 
(ACI) option.
5. Industry Profits
    Hazardous waste-burning profits for all combustion sectors, on 
average, are expected to decline post-rule. This decline, however, will 
not be consistent across sectors. Hazardous waste-burning profits for 
cement kilns are projected to decrease by no more than 10 percent, 
while profits for commercial incinerators would decrease by no more 
than 2 percent. These profit margin estimates are based on a simple 
calculation that subtracts projected operating costs from revenues. 
These estimates provide relative measures of profit changes and should 
not be used to predict absolute profit margins in these industries.
    Compliance costs associated with meeting today's rule are estimated 
to represent less than 2 percent of the pollution control expenditures 
in industries that contain facilities with on-site incinerators. For 
cement kilns, however, compliance costs are expected to increase total 
pollution control expenditures by no more than 60 percent at waste-
burning facilities.
    To comply with today's rule, many facilities will need to purchase 
additional pollution control equipment. From the perspective of the 
pollution control industry, these expenditures will translate into 
additional revenues and profits. Total profits for the air pollution 
control industry are likely to increase as a result of today's rule.
6. National-Level Joint Economic Impacts
    Analyzing national-level economic impacts in a market context 
provides an opportunity to assess the distributional effects on cement 
producers, lightweight aggregate kilns, and commercial incinerators. As 
a supplement to today's analysis, we used the model developed for the 
Portland Cement MACT rulemaking to estimate national-level economic 
impacts of today's Hazardous Waste Combustion (HWC) MACT rule in an 
interactive market context. This analysis was conducted to estimate 
joint impacts of today's rule in conjunction with the Portland Cement 
MACT rule and the Cement Kiln Dust rule. The Portland Cement MACT model 
incorporates compliance costs for each affected cement kiln, 
lightweight aggregate kiln, and commercial incinerator and then 
projects national level impacts associated with these facilities and 
for the general Portland cement market. On-site incinerators were not 
included in this analysis because they do not generally compete in the 
commercial hazardous waste combustion market. Results from this 
analysis are separated into three categories: Market-, industry-, and 
social-level impacts associated with imposition of the recommended 
final standards and the two HWC MACT options (floor and beyond-the-
floor (ACI)).
    Joint national-level economic impact results combining the HWC MACT 
options with the Portland Cement MACT and Cement Kiln Dust Rule are 
summarized in this section. Market, industry, and social cost impacts 
are discussed. This analysis assumes simultaneous implementation of all 
three rules.
    Market-level impacts for this joint scenario, assuming the floor 
option, result in increased costs of cement production and burning 
hazardous waste at affected cement kilns. The national market price of 
Portland cement is projected to increase by about 2.0 percent, while 
domestic production would decline by about 4.0 percent. Market impacts 
for the joint scenario with the recommended final standards and the 
beyond-the-floor (ACI) option were found to be generally equivalent to 
results under the floor option. The extent to which domestic cement 
producers face competition from foreign cement imports will limit the 
degree of domestic price increases. Furthermore, the U.S. cement market 
is regionally specific. While nationwide average market price and 
production impacts are estimated to be relatively minor, producers in 
selected regions may experience significant revenue and production 
impacts, either positive or negative.
    Under the joint scenario with the floor option, the market prices 
for both liquid and solid hazardous waste incineration are projected to 
increase by about 8.6 percent and 1.4 percent, respectively. The price 
change for liquids is higher than that observed for the floor only, 
while the price change for solids is virtually the same. For cement 
kilns, the increased costs associated with all three regulations, 
combined with their reductions in cement production, is projected to 
cause their supply of hazardous waste incineration services to fall by 
around 11.0 percent for both liquids and solids. In response to the 
regulatory costs, lightweight aggregate kilns also reduce their supply 
of liquid hazardous waste incineration by around 9.0 percent. For 
commercial incinerators, the supply of hazardous waste incineration 
increases by nearly 6.0 percent for liquids and close to 3.0

[[Page 53019]]

percent for solids. The market impacts for the joint scenario, using 
the recommended final standards and the beyond-the-floor (ACI) 
alternative, were found to be similar to those for the floor option. 
One exception is the market price for liquids, which increases by a 
greater percentage under the joint scenario with the beyond-the-floor 
(ACI) alternative. This results in a greater reduction in liquid 
hazardous waste burned at cement kilns and lesser decreases in liquids 
incinerated at commercial incinerators.
    Industry-level impacts under the joint impacts scenario with the 
floor option indicate that Portland cement plants may see total gross 
revenues decline by nearly 3.0 percent from their current baseline. 
This decline in total revenue results from foregone revenues associated 
with producing less Portland cement and lost revenues from burning 
hazardous waste. The total net costs for these cement plants are also 
projected to decrease, reflecting the increase in costs associated with 
burning hazardous waste, plus the increase in cement kiln dust 
management costs, and the decrease in costs associated with producing 
less cement. The net result, indicates a decline in aggregate 
nationwide earnings before interest and taxes (EBIT) of about 5.5 
percent from the current baseline. Lightweight aggregate kilns are also 
projected to incur a decline in hazardous waste-related EBIT of about 
5.5 percent. Alternatively, as a group, the commercial incinerators are 
expected to experience a net gain of around 11.0 percent in annual 
earnings under this joint scenario with the floor option. These joint 
industry-level impacts on EBIT indicate a similar pattern across each 
regulatory scenario, except for lightweight aggregate kilns under the 
beyond-the-floor (ACI) option, where EBIT declines by nearly 14.0 
percent. Industry-level impacts under the joint impact analysis also 
includes estimates of plant or system closures. The joint analysis 
under each hazardous waste combustion scenario indicates that three 
cement plants and 14 to 15 kilns may cease production. Furthermore, 
five cement kilns are projected to stop burning hazardous waste. The 
analysis also indicates that one lightweight aggregate kiln may 
discontinue burning hazardous waste and one to two commercial 
incinerators may close operations and stop burning hazardous waste with 
the joint implementation of all three rules. These market exit 
estimates include projected baseline closures.
    Social-level impacts, or social costs, under the joint scenarios 
indicate that, for both Portland cement and hazardous waste 
incineration services, consumers are worse off due to the increase in 
prices and reductions in consumption. For producers of Portland cement 
and incineration services, cement kilns and lightweight aggregate kilns 
are worse off (on a nationwide basis) due to the decline in market 
share, while commercial incinerators are better off due to the increase 
in prices and market share.
    Refer to the final Assessment document and appendices for a 
complete discussion of joint impacts.
G. Analytical Methodology and Findings--Benefits Assessment
    This section discusses the benefits assessment for today's rule. 
Results from our multi-pathway human health and ecological risk 
assessment are used to evaluate incremental benefits to society of 
emission reductions at hazardous waste combustion 
facilities.351 Total monetized benefits are estimated at 
$19.2 million. This section also summarizes how today's rule may lead 
to changes in the types and quantities of wastes generated and managed 
at combustion facilities through increased waste minimization.
---------------------------------------------------------------------------

    \351\ The RIA for the proposal included results from a screening 
analysis designed to assess the potential magnitude of property 
value benefits caused by the MACT standards. This analysis is not 
included in the Economic Assessment for the Final Rule due to 
limitations of the benefits transfer approach and because property 
value benefits likely overlap with human health and ecological 
benefits. Including property value benefits would result in double-
counting.
---------------------------------------------------------------------------

1. Human Health and Ecological Benefits
    a. Risk Assessment Overview. The basis for the benefits assessment 
is our multi-pathway risk assessment model. This model estimates 
baseline risks from hazardous waste combustion emissions, as well as 
expected risks after today's rule is implemented. The model examines 
both inhalation and ingestion pathways to estimate human health risks. 
A less detailed screening-level analysis is used to identify the 
potential for ecological risks. The risk assessment is carried out for 
the regulatory baseline (no regulation), the final recommended 
standards, and the two MACT options (floor and beyond-the-floor (ACI)). 
The assessment uses a case study approach in which 76 hazardous waste 
combustion facilities and their site-specific land uses and 
environmental settings are characterized. The randomly selected 
facilities in the study include 43 on-site incinerators, 13 commercial 
incinerators, 15 cement kilns, and five lightweight aggregate kilns.
    The pollutants analyzed in the risk assessment are dioxins and 
furans, selected metals, particulate matter, chlorine, and hydrogen 
chloride. The metals modeled in the analysis include antimony, arsenic, 
barium, beryllium, cadmium, chromium, copper, cobalt, lead, manganese, 
mercury, nickel, selenium, silver, and thallium. The fate and transport 
of the emissions of these pollutants is modeled to arrive at 
concentrations in air, soil, surface water, and sediments. To assess 
human health risks, these concentrations can be converted to estimated 
doses to the exposed populations using exposure factors such as 
inhalation and ingestion rates. These doses are then used to calculate 
cancer and noncancer risks, if the appropriate health benchmarks are 
available. To assess potential ecological risks, soil, surface water 
and sediment concentrations are compared with eco-toxicological 
criteria representing protective screening values for ecological risks. 
Because these criteria are based on de minimis ecological effects and 
thus represent conservative values, an exceedance of the eco-
toxicological criteria does not necessarily indicate ecological 
damages. It simply suggests that potential damages cannot be ruled out.
    To characterize the cancer and noncancer risks to the populations 
listed above, the risk assessment breaks down the area surrounding each 
modeled combustion facility into 16 polar grid sectors. For each polar 
grid sector, risk estimates can be developed for different age groups 
and receptor populations (e.g., 0 to 5 year old children of subsistence 
fishers). This approach is used because geographic and demographic 
differences across polar grid sectors leads to sectoral variation in 
individual risks. Thus, individual risk results are aggregated across 
sectors to generate the distribution of risk to individuals in the 
affected area. An additional Monte Carlo analysis was conducted to 
incorporate variability in other exposure factors such as inhalation 
and ingestion rates for three scenarios that were thought to comprise 
the majority of the risk to the study area population. These scenarios 
address cancer risk from dioxin exposure to beef and dairy farms and 
noncancer risk from methyl mercury exposure to recreational anglers.
    b. Human Health Benefits--Methodology. Human health benefits are 
assessed by identifying those pollutants for which emission reductions 
are expected to result in improvements to human health or the

[[Page 53020]]

environment. The relevant results from the risk assessment for the 
pollutants of concern are then examined, focusing on population risk 
results based on central tendency exposure parameters. The risk 
assessment data are expressed as indicators of potential benefits, such 
as reduced cancer incidence or reduced potential for developing 
particular illnesses or abnormalities. Where possible, monetary values 
are assigned to these benefits using a benefits transfer approach.
    To assign monetary values to cancer risk reduction estimates, we 
apply the value of a statistical life to the risk reduction expected to 
result from the MACT standards. The value of a statistical life is 
based on an individual's willingness to pay to reduce a risk of 
premature death or their willingness to accept increases in mortality 
risk. Because there are many different estimates of value of a 
statistical life in the economic literature, we estimate the reduced 
mortality benefits using a range of value of a statistical life 
estimates from 26 policy-relevant value-of-life studies. The estimated 
value of a statistical life figures from these studies range from $0.7 
million to $15.9 million (adjusted to 1996 dollars), with a mean value 
of $5.6 million. The expected number of annual premature statistical 
deaths avoided are multiplied by the value of a statistical life 
estimate to determine the estimated monetary value of the mortality 
risk reductions.
    A variety of approaches are used to evaluate the benefits 
associated with noncancer risk reductions. For particulate matter, both 
morbidity and mortality benefits are estimated. Particulate matter is 
the only non-carcinogen in the risk assessment for which there is 
sufficient dose-response information to estimate numbers of cases of 
disease and deaths from exposures. For lead and mercury, upper bound 
estimates of the population at risk are used. This is because 
information is only available on the potential of an adverse effect, 
with no estimates available on the likelihood of these effects.
    We assign monetary values to noncancer benefits using a direct cost 
approach which focuses on the expenditures averted, and the opportunity 
cost of time spent in the hospital, by decreasing the occurrence of an 
illness or other health effect. While the willingness to pay approach 
used for valuing the cancer risk reductions is conceptually superior to 
the direct cost approach, measurement difficulties, such as estimating 
the severity of various illnesses, precludes us from using this 
approach here. Direct cost measures are expected to understate true 
benefits because they do not include cost of pain, suffering, and time 
lost. On the other hand, because we use upper bound estimates of the 
population at risk, we cannot conclude that the results are biased in 
one direction or the other.
    c. Human Health Benefits--Results. Human health benefits are 
expected from both cancer and noncancer risk reductions. Less than one 
cancer case per year is expected to be avoided due to reduced emissions 
from combustion facilities. The majority of the cancer risk reductions 
are linked to consumption of dioxin-contaminated agricultural products 
exported beyond the boundaries of the study area. Less than one-third 
of the cancer risk reductions occur in local populations living near 
combustion facilities. Cancer risks for local populations are 
attributed primarily to reductions in arsenic and chromium emissions. 
These pollutants account for almost 85 percent of total local cancer 
incidences in the baseline. By applying value of a statistical life 
estimates to these cases, the total annual cancer risk reductions 
(benefits) in going from the baseline to the final standards, are 
valued at between $0.13 and $9.9 million, with a best estimate of 
approximately $2.02 million.
    Across all receptor populations, individual cancer risks are 
greatest for subsistence farmers. Dioxin is the primary pollutant that 
drives the cancer risk for this sensitive receptor population. A lack 
of population data prevented us from quantifying benefits for this sub-
population. It is possible, however, to characterize the reduction in 
risk from baseline to implementation of today's rule. With the 
exception of one particular scenario, the cancer risk for all 
subsistence farmers is reduced to below levels of concern after 
implementation of today's rule. Today's rule is also expected to result 
in lower cancer risks for children of subsistence farmers.
    Most of the noncancer human health benefits from today's rule come 
from reductions in particulate matter. Some additional noncancer 
benefits come from reduced blood lead levels in children living near 
combustion facilities. Total annual noncancer benefits from 
quantifiable sources are valued at between $9.85 and $73.8 million, 
with a best estimate of about $17.2 million. Uncertainties implicit in 
the quantitative mercury analysis continue to be sufficiently great so 
as to limit its ultimate use in the monetization of noncancer benefits. 
Please review the Addendum and chapter six of the Assessment document 
for a complete discussion of human health benefits resulting from 
today's rule.
    d. Ecological Benefits--Methodology. Ecological benefits are based 
on a screening analysis for ecological risks that compares soil, 
surface water, and sediment concentrations with eco-toxicological 
criteria based on de minimis thresholds for ecological effects. Because 
these criteria represent conservative values, an exceedance of the eco-
toxicological criteria only indicates the potential for adverse 
ecological effects and does not necessarily indicate ecological 
damages. For this reason, benefits of avoiding adverse ecological 
impacts are discussed only in qualitative terms.
    The basic approach for determining whether ecosystems or biota are 
potentially at risk consists of five steps: (1) Identify susceptible 
ecological receptors that represent relatively common species and 
communities of wildlife, (2) develop eco-toxicological criteria for 
receptors that represent acceptable pollutant concentrations, (3) 
estimate baseline and post-rule pollutant concentrations in sediments, 
soils, and surface waters of the study areas, (4) for each land area or 
water body modeled, compare the modeled media concentrations to 
ecologically protective levels to estimate eco-toxicological hazard 
quotients, and (5) total the land and water areas containing hazard 
quotients exceeding one and compare this number for the baseline and 
post-rule scenario. The reduction in the land and water area 
potentially at risk indicates a potential for avoiding adverse 
ecological impacts. Monetary values are not assigned to these potential 
benefits.
    e. Ecological Benefits--Results. Ecological benefits are 
attributable primarily to reductions in dioxin and mercury for 
terrestrial ecosystems. For these ecosystems, hazard quotients are 
reduced to acceptable levels for approximately 115 to 150 square 
kilometers of land located within 20 kilometers of all combustion 
facilities. Ecological benefits associated with freshwater aquatic 
ecosystems are attributable to reductions in lead, with hazard 
quotients reduced to acceptable levels for approximately 35 to 40 
square kilometers of these surface waters. These reductions of 
ecological risk criteria below levels of concern only indicates a 
potential for ecological improvement.
2. Waste Minimization Benefits
    While many facilities may implement end-of-pipe controls such as 
fabric

[[Page 53021]]

filters and high-energy scrubbers to achieve MACT control, emission 
reductions may also be accomplished by reducing the volume or toxicity 
of wastes currently combusted. In addition, generators may also 
consider waste management alternatives such as solvent recycling. For 
purposes of this analysis, these types of responses will be referred to 
as ``waste minimization.'' This section summarizes the potential waste 
minimization benefits resulting from implementation of today's rule.
    As today's rule is implemented, the costs of burning hazardous 
waste will increase, resulting in market incentives for greater waste 
minimization. To predict the quantity of waste that could be 
reallocated from combustion to waste minimization due to economic 
considerations, we conducted a comprehensive waste minimization 
analysis that considered in-process recycling, out-of-process 
recycling, and source reduction. The objective of the analysis was to 
predict the quantity of hazardous wastes that may be reallocated to 
these waste minimization alternatives under different combustion price 
increase scenarios.
    Overall, the analysis shows that a variety of waste minimization 
alternatives are available for managing those hazardous waste streams 
that are currently combusted. The quantity projected to be reallocated 
from combustion to waste minimization alternatives, however, depends 
upon the expected price increase for combustion services. At potential 
price increases ranging from $10 to $20 per ton, as much as 240,000 
tons of hazardous waste may be reallocated from combustion to waste 
minimization alternatives. This represents approximately 7 percent of 
the total quantity of hazardous waste currently combusted.

VI. What Considerations Were Given to Issues Like Equity and Children's 
Health?

    By applicable statute and executive order, we are required to 
complete an analysis of today's rule with regard to equity 
considerations and other regulatory concerns. This section assesses the 
potential impacts of today's rule as it relates to environmental 
justice, children's health issues, and unfunded federal mandates. Small 
entity impacts are examined in a separate section.
A. Executive Order 12898, ``Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations'' (February 
11, 1994)
    This Order is designed to address the environmental and human 
health conditions of minority and low-income populations. To comply 
with the Executive Order, we have assessed whether today's rule may 
have disproportionate effects on minority populations or low-income 
populations. We have analyzed demographic data presented in the reports 
``Race, Ethnicity, and Poverty Status of the Populations Living Near 
Cement Plants in the United States'' (EPA, August 1994) and ``Race, 
Ethnicity, and Poverty Status of the Populations Living Near Hazardous 
Waste Incinerators in the United States'' (EPA, October 1994). These 
reports examine the number of low-income and minority individuals 
living near a relatively large sample of cement kilns and hazardous 
waste incinerators and provide county, state, and national population 
percentages for various sub-populations. The demographic data in these 
reports provide several important findings when examined in conjunction 
with the risk reductions projected from today's rule.
    We find that combustion facilities, in general, are not located in 
areas with disproportionately high minority and low-income populations. 
However, there is evidence that hazardous waste burning cement kilns 
are somewhat more likely to be located in areas that have relatively 
higher low-income populations. Furthermore, there are a small number of 
commercial hazardous waste incinerators located in highly urbanized 
areas where there is a disproportionately high concentration of 
minorities and low-income populations within one and five mile radii. 
The reduced emissions at these facilities due to today's rule could 
represent meaningful environmental and health improvements for these 
populations. Overall, today's rule should not result in any adverse 
environmental or health effects on minority or low-income populations. 
Any impacts on these populations are likely to be positive due to the 
reduction in emissions from combustion facilities near minority and 
low-income population groups. The Assessment document available in the 
RCRA docket established for today's rule presents the full 
Environmental Justice Analysis.
B. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks (62 FR 19885, April 23, 1997)
    Executive Order 13045: ``Protection of Children from Environmental 
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies 
to any rule that: (1) Is determined to be ``economically significant'' 
as defined under E.O. 12866, and (2) concerns an environmental health 
or safety risk that EPA has reason to believe may have a 
disproportionate effect on children. If the regulatory action meets 
both criteria, the Agency must evaluate the environmental health or 
safety effects of the planned rule on children, and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the Agency.
    Today's final rule is not subject to the Executive Order because it 
is not economically significant as defined under point one of the 
Order, and because the Agency does not have reason to believe the 
environmental health or safety risks addressed by this action present a 
disproportionate risk to children.
    The topic of environmental threats to children's health is growing 
in regulatory importance as scientists, policy makers, and village 
members continue to recognize the extent to which children are 
particularly vulnerable to environmental hazards. Recent EPA actions 
including today's rule, are in the forefront of addressing 
environmental threats to the health of children. The risk assessment 
conducted in support of today's rule indicates that children are the 
beneficiaries of much of the reduction in potential illnesses and other 
adverse effects associated with combustion facility emissions. The risk 
assessment used a multi-pathway and multi-constituent evaluation in 
order to examine potential effects of combined exposures on children. 
Setting environmental standards that address combined exposures and 
that are protective of the heightened risks faced by children are both 
goals named within EPA's ``National Agenda to Protect Children's Health 
from Environmental Threats.'' Areas for potential reductions in risks 
and related health effects that were identified by the risk assessment 
are all targeted as priority issues within EPA's September 1996 report, 
Environmental Health Threats to Children.
    A few significant physiological characteristics are largely 
responsible for children's increased susceptibility to

[[Page 53022]]

environmental hazards. First, children eat proportionately more food, 
drink proportionately more fluids, and breathe more air per pound of 
body weight than do adults. As a result, children potentially 
experience greater levels of exposure to environmental threats than do 
adults. Second, because children's bodies are still in the process of 
development, their immune systems, neurological systems, and other 
immature organs can be more easily and considerably affected by 
environmental hazards. The connection between these physical 
characteristics and children's susceptibility to environmental threats 
are reflected in the higher baseline risk levels for children living 
near hazardous waste combustion facilities. The risk assessment 
addresses threats to children's health associated with hazardous waste 
combustion by evaluating reductions in risk for children as well as for 
adults and the population overall. For all exposed sub-populations, the 
assessment evaluated risks to four different age groups: 0 to 5 years, 
6 to 11 years, 12 to 19 years, and adults over 20 years. Where 
possible, the risk assessment has provided both population and 
individual risk results for children. Both cancer and noncancer risks 
are examined across the age groups of children, focusing on the most 
susceptible sub-populations. The combined effects of several 
carcinogens, one of the goals named within the Agency's ``National 
Agenda to Protect Children's Health from Environmental Threats,'' were 
examined.
    The key findings from the risk assessment indicate that children do 
not face significant cancer risks from hazardous waste combustion 
emissions. Only in the case of children of subsistence farmers do 
baseline cancer risks exceed 1 x 10-5 for the most highly 
exposed children. Implementation of the final standards would reduce 
these risks below levels of concern 352.
---------------------------------------------------------------------------

    \352\ Also, the analysis used the same approach to estimate 
cancer risks in both adults and children. However, individuals 
exposed to carcinogens in the first few years of life may be at 
increased risk of developing cancer. For this reason, we recognize 
that significant uncertainties and unknowns exist regarding the 
estimation of lifetime cancer risks in children. We also note that 
this analysis of cancer risks in children has not been externally 
peer reviewed.
---------------------------------------------------------------------------

    The analysis also found that much of the noncancer risk reductions 
resulting from implementation of today's rule may benefit children 
specifically. These are projected as a result of lower exposures to 
mercury, lead, and particulate matter, three types of pollutants 
addressed in the noncancer risk reductions which primarily affect 
children. Mercury emission reductions may reduce risks of developmental 
abnormalities in potential future offspring of recreational anglers and 
subsistence fishermen. In addition, particulate matter reductions may 
prevent some asthma attacks affecting children, but these benefits have 
not been quantified. Finally, reduced lead exposures for children are 
expected from today's rule. This benefit may help prevent cognitive and 
nervous system developmental abnormalities for children of the most 
highly exposed sub-populations, including subsistence fishermen and 
beef and dairy farmers. Analytical and data limitations prevented 
reasonable monetization of these findings.
C. Unfunded Mandates Reform Act of 1995 (UMRA) (Pub. L. 104-4)
    Executive Order 12875, ``Enhancing the Intergovernmental 
Partnership'' (October 26, 1993), calls on federal agencies to provide 
a statement supporting the need to issue any regulation containing an 
unfunded federal mandate and describing prior consultation with 
representatives of affected state, local, and tribal governments. 
Signed into law on March 22, 1995, the Unfunded Mandates Reform Act 
(UMRA) supersedes Executive Order 12875, reiterating the previously 
established directives while also imposing additional requirements for 
federal agencies issuing any regulation containing an unfunded mandate.
    Today's rule is not subject to the requirements of sections 202, 
204 and 205 of UMRA. In general, a rule is subject to the requirements 
of these sections if it contains ``Federal mandates'' that may result 
in the expenditure by State, local, and tribal governments, in the 
aggregate, or by the private sector, of $100 million or more in any one 
year. Today's final rule does not result in $100 million or more in 
expenditures. The aggregate annualized social costs for today's rule 
are projected to range from $50 to $63 million under the final 
standards.
    For rules that are subject to the requirements of these sections, 
key requirements include a written statement with an analysis of 
benefits and costs; input from state, local and tribal governments; and 
selection of the least burdensome option (if allowed by law) or an 
explanation for the option selected. We recognize the potential for 
aggregate one-time capital expenditures to exceed $100 million in any 
one year should various industry sectors choose not to amortize capital 
expenditures. Under this scenario, the Assessment document for today's 
rule meets analytical requirements established under UMRA.
    Today's rule is not subject to the requirements of section 203 of 
UMRA. Section 203 requires agencies to develop a small government 
Agency plan before establishing any regulatory requirements that may 
significantly or uniquely affect small governments, including tribal 
governments. EPA has determined that this rule will not significantly 
or uniquely affect small governments. The small entity impacts 
analysis, presented in Appendix G of the final Assessment, found that 
no hazardous waste combustion units are owned by small governments.
    Finally, because we are issuing today's rule under the statutory 
authority of the Clean Air Act, the rule should be exempt from all 
relevant requirements of the UMRA. In addition, compliance with the 
rule is voluntary for nonfederal governmental entities since state and 
local agencies choose whether or not to apply to EPA for the permitting 
authority necessary to implement today's rule.

VII. Is Today's Rule Cost Effective?

    We have developed a cost-effectiveness measure that examines cost 
per unit reduction of emissions for each hazardous air pollutant, 
pollutant group, or surrogate. Cost-effectiveness measures are useful 
for comparing across different air pollution regulations. Moreover, we 
have typically used cost-effectiveness measures (defined as ``dollar-
per-unit of pollutant removed'') to assess the decision to go beyond-
the-floor for MACT standards.
    Developing cost-effectiveness estimates for individual air 
pollutants assists us in making beyond-the-floor decisions for 
individual pollutants. The two analytic components of the individual 
cost-effectiveness analysis are: (1) Estimates of emission control 
expenditures per air pollutant for each regulatory option, and (2) 
estimates of emission reductions under each regulatory option. 
Individual cost-effectiveness measures for each MACT option are 
calculated as follows:
     HWC MACT Floor--Costs and emission reductions are 
incremental to the baseline,
     HWC MACT Final Standards--Costs and emission reductions 
are incremental to the MACT Floor, and
     Beyond-the-Floor--Activated Carbon Injection (ACI) MACT--
Costs and emission reductions are incremental to the MACT Floor.
    Single-level cost-effectiveness results across all HWC MACT options 
range

[[Page 53023]]

from seven hundred dollars to $34.3 million per megagram reduced for 
all pollutants, individually, except dioxin. Dioxin control ranges from 
$25,000 to $903,000 per gram reduced. Dioxin control for incinerators 
to meet the floor standard is estimated at $903,000 per gram, with an 
additional $368,000 per gram to go from the floor to the final BTF TEQ 
standard. The control of SVM emitted from cement kilns is estimated to 
cost $67,000 per megagram from the baseline to the floor. Moving from 
the floor standard to the final BTF SVM standard for cement kilns is 
estimated to cost $502,000 per megagram. These results indicate that 
the more highly toxic pollutants such as dioxin are often much more 
expensive to control on a per-gram basis.
    We did not apply cost-effectiveness alone in establishing beyond-
the-floor levels for selected constituents regulated under the final 
HWC MACT standards. Several other measurement factors were incorporated 
into the beyond-the-floor decision, including: health benefits 
(especially those for children), regulatory precedent, cost-
effectiveness of other MACT standards, and reliability of baseline 
data.
    The method for calculating cost-effectiveness makes several 
simplifying assumptions. The two most important address the metrics 
employed for measuring cost-effectiveness and the actual methodology 
used to estimate the cost and emission reduction figures. Alternative 
measurement criteria for different constituents may lead to perceived 
distortions in scope. The cost-effectiveness methodology assumes that 
all facilities continue operating and install pollution control 
equipment or implement feed reductions to comply with the MACT 
standards. Both of these limiting assumptions may lead to overstatement 
or understatement of results. Other limitations that will influence 
these cost-effectiveness estimates include: (1) The feed control 
costing approach, which may lead to the overstatement of expenditures 
per pollutant due to the assumption of upper-bound cost estimates, (2) 
apportionment of costs, which are currently assigned according to the 
percentage reduction required to meet the standard for each pollutant 
controlled by the device, and (3) the assumption that units control 
emissions to the 70 percent design level.

VIII. How Do the Costs of Today's Rule Compare to the Benefits?

    Comparing overall costs and benefits may help provide an assessment 
of this rule's overall efficiency and impacts on society. This section 
compares the total social costs of today's rule with its total 
monetized and nonmonetized benefits. The total annual monetized 
benefits of today's rule are estimated at $19.2 million (undiscounted) 
for the recommended final standards. These monetized benefits, however, 
may represent only a subset of potential avoided health effects, both 
cancer and noncancer cases. In comparison, the total annualized social 
costs of the rule are projected to range from $50 to $63 million. 
Social costs also include government administrative costs.
    Across regulatory options, costs exceed monetized benefits more 
than two-fold. However, today's rule is expected to provide benefits 
that cannot be readily expressed in monetary terms. These benefits 
include health benefits to sensitive sub-populations such as 
subsistence anglers and improvements to terrestrial and aquatic 
ecological systems. When these benefits are taken into account, along 
with equity-enhancing effects such as environmental justice and impacts 
on children's health, the benefit-cost comparison becomes more complex 
but also more favorable. Consequently, the final regulatory decision 
becomes a policy judgment which takes into account efficiency as well 
as equity concerns and the positive direction of real, but 
unquantifiable, benefits.

IX. What Consideration Was Given to Small Businesses?

A. Regulatory Flexibility Act (RFA) as amended by the Small Business 
Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 USC 601 et seq.
    This Act generally requires an agency to prepare a regulatory 
flexibility analysis of any rule subject to notice and comment 
rulemaking requirements under the Administrative Procedure Act or any 
other statute unless the agency certifies that the rule will not have a 
significant economic impact on a substantial number of small entities. 
Small entities include small businesses, small not-for-profit 
enterprises, and small governmental jurisdictions.
    We have determined that hazardous waste combustion facilities are 
not owned by small entities (local governments, tribes, etc.) other 
than businesses. Therefore, only businesses were analyzed. For the 
purposes of the impact analyses, small entity is defined either by the 
number of employees or by the dollar amount of sales. The level at 
which a business is considered small is determined for each Standard 
Industrial Classification (SIC) code by the Small Business 
Administration.353
---------------------------------------------------------------------------

    \353\ SIC codes are used rather than the new NAICS codes because 
waste generator, blender, and combustor data were only available 
according to SIC code. However, a general conversion table 
containing NAICS codes for each reported SIC code is presented in 
the Assessment document.
---------------------------------------------------------------------------

    Affected individual waste combustors (incinerators, cement kilns, 
and lightweight aggregate kilns) will bear the impacts of today's rule. 
These units will incur direct economic impacts as a result of today's 
rule. While not required under the Act and guidelines, we have also 
examined potential secondary impacts on small business units 
potentially affected by today's rule, such as hazardous waste 
generators and fuel blenders. Although hazardous waste combustors are 
the only group that would bear direct economic impacts from today's 
rule, this ``secondary impacts'' analysis was conducted because we 
assume that some portion of the burden would be passed on to customers 
of combustion facilities through price increases. This section 
describes the small entity analysis we conducted in support of today's 
rule.
B. Analytical Methodology
    For combustors and blenders, we conducted facility-by-facility 
analyses of small businesses. We examined company data on employment 
and sales and then compared these data to statutory small business 
thresholds based on employment or annual sales, as defined for its 
industry by the Small Business Administration in 13 CFR part 121. 
Combustion or blender units where the facility or parent company data 
fell below the small business thresholds were classified as small 
businesses. The analysis was more complex for generators, however, 
because the rule may indirectly affect more than 11,000 generators. 
Given the large number of generators who would be affected by today's 
rule, it was necessary to conduct an initial, broad screening analysis 
to identify small business generators that might face significant 
secondary impacts. This screening analysis involved assigning each 
facility to an industry group, identifying industry groups that are 
dominated by small businesses, and then assuming that all generators in 
those small business dominated industries are small. Further analyses 
were then conducted on these groups or specific facilities.
    We next compiled compliance cost data in an effort to establish a 
threshold for measuring ``significant economic impact.'' This threshold 
was set where compliance costs exceed one percent of

[[Page 53024]]

facility gross sales. If costs do not exceed one percent of sales, then 
the regulation is unlikely to have a significant economic impact on 
small businesses within the category examined. Finally, we examined 
whether the significant economic impact (if any) would be borne by a 
``substantial number'' of small businesses. If the regulation results 
in required compliance costs exceeding one percent of gross sales for 
more than 100 small businesses or 20 percent of all small businesses 
within the industry category examined, then the ``substantial number'' 
threshold is exceeded.
    The cost of compliance with the new standards will determine the 
severity of impacts on small businesses. The costs to combustors used 
in this analysis coincide with the 70 percent engineering standard 
analyzed in the full economic assessment. The price increases 
experienced by generators and blenders were calculated on a per ton 
basis of waste shipped using 25 and 75 percent price pass-through 
scenarios. The price impacts were assumed to be uniform across facility 
types, with both generators and blenders experiencing the price pass-
through effect. In practice, this pass through would likely be split 
between the two, depending on market factors. Note that the impacts 
from these price increases are indirect effects, as only hazardous 
waste combustors bear direct economic impact of today's rule.
C. Results--Direct Impacts
    Only six facilities, out of the total universe of 172 hazardous 
waste combustion facilities, met the definition of small businesses. Of 
these six, two were found to experience annual compliance costs 
exceeding one percent of sales. Both of these facilities are owned by a 
common parent that qualifies as a small business. Therefore, this final 
rule affects a very limited number of small business combustors and has 
effects of greater than one percent on only two of these facilities 
(one business).
    While the significant economic impact threshold was exceeded for 
two facilities (one corporation), these impacts do not extend to a 
substantial number of small entities. With just two facilities 
exceeding the one percent threshold, neither a substantial number of 
facilities nor a substantial fraction of an affected industry would 
face these impacts. After considering the economic impacts of today's 
final rule on small entities, I certify that this action will not have 
a significant economic impact on a substantial number of small 
entities.
    Although this final rule will not have a significant economic 
impact on a substantial number of directly impacted small entities, EPA 
nonetheless has assessed the potential of this rule to adversely impact 
small entities subject to the rule.
D. Results--Indirect Impacts
    Direct impacts of the rule extend only to combustors of hazardous 
waste. To supplement our analysis, indirect impacts on generators and 
blenders were also examined. We understand that some portion of the 
combustor's compliance costs would most likely be passed on to 
generators and blenders, and we have made an effort to analyze these 
impacts in the spirit of the legislation.
    We found that indirect economic effects on generators would not 
impose a significant impact on a substantial number of small 
generators. Under both price pass-through scenarios (25 and 75 
percent), some generators exceeded the one percent cost as percentage 
of sales threshold for ``significant impacts.'' In no case, however, 
was the ``substantial number'' threshold exceeded. Under the 25 percent 
pass-through scenario, 18 generators had a cost as percentage of sales 
greater than one percent, but that accounts for only 0.85 percent of 
all small business generators. While the impact threshold was exceeded 
by 58 generators in the 75 percent pass through scenario, this is still 
less than the 100 entity threshold established for a substantial 
number. You should note that the sales thresholds were selected 
conservatively as the average sales for the smallest establishments in 
the SIC code.
    Like generators, blenders do not incur direct costs as a result of 
the rule. However, they may bear a portion of its impact indirectly as 
costs are passed through from combustors. A total of 21 small business 
blenders were identified. Depending on the pass-through assumption, 
between six and 14 blenders exceed the significant impact threshold. 
Impacts for some of these facilities were found to represent a 
significant share of their annual gross sales.
    Under the 25 percent price pass-through scenario, the number of 
blenders exceeding the cost as percentage of sales threshold do not 
represent a substantial number of facilities, either in absolute number 
or as a percentage of total blenders. Under the 75 percent scenario, 
however, the 14 establishments with cost as percentage of sales greater 
than one percent represent just over 20 percent of the 67 blenders 
identified for this analysis. In a few cases, the cost as percentage of 
sales could exceed 10 percent.
E. Key Assumptions and Limitations
    This analysis was based on several simplifying assumptions. Four 
key assumptions may have the most significant impact on findings. 
First, not all small generators may be captured in our analysis of 
small business dominated industries. This exclusion may be offset by 
the fact that some generators who are not small may be incorporated in 
the small business dominated industries. Second, to calculate the 
benchmark sales for generators, we used average sales by four-digit SIC 
code for firms with fewer than 20 employees. This may understate 
economic impacts for the smallest firms in the industry while 
overstating impacts for larger firms. Third, compliance costs were 
assumed to be passed through almost completely to the shipper of the 
waste. This may overstate the impact on generators and blenders. 
Finally, we assumed that all waste currently managed by combustion 
continues to be disposed of in this manner. Impacts on combustors, 
generators, and blenders may be overstated if waste minimization or 
other lower cost alternatives are available.
    Results from this report should also be evaluated within the 
context of some key analytical limitations. For example, in recent 
years there has been significant volatility in market behavior and 
pricing practices in the hazardous waste combustion industry. 
Furthermore, combustion prices have experienced a general downward tend 
since 1985 as a result of overcapacity in the market and slow growth in 
the generation of hazardous waste. Accounting for this price trend, the 
increase expected under today's rule may affect generators and blenders 
less significantly than anticipated. Finally, many hazardous waste 
generators may be more concerned about other aspects of waste 
management than with prices.

X. Were Derived Air Quality and Non-Air Impacts Considered?

    The final Combustion MACT standards are projected to result in the 
reallocation and diversion of relatively small amounts of hazardous 
waste resulting in an unspecified increase in the level of fossil fuel 
substitution. This substitution with nonhazardous waste fuel sources 
may result in marginal increases in the annual number of mining and 
transport injuries, in addition to potential increased emissions of 
criteria pollutants (SOx, NOx, and 
CO2). We recognize these

[[Page 53025]]

concerns but feel any potential non-air impacts are largely addressed 
through alternative regulatory or market scenarios. First, some of the 
hazardous waste reallocated from current combustors will likely be sent 
to other waste-burning facilities, thereby off-setting primary or 
supplementary fossil fuel usage. Even if fossil fuel burning does 
increase to some degree, these SO2 and NOx 
emissions are expected to be regulated under existing standards, e.g., 
criteria pollutant emissions are currently addressed by the Clean Air 
Act. Finally, we find that even if fossil fuel use is increased, the 
risks to miners (primarily coal miners) are voluntary risks. Miners are 
compensated for these increased risks through wage premiums established 
in response to market dynamics and recurrent negotiations between union 
and corporate representatives.
    While the primary environmental impact of the MACT standards are 
improvements in air quality resulting from emissions reductions at 
combustion facilities, other non-air environmental impacts also result 
from the rule. Namely, use of some air pollution control equipment and 
shifts in waste burning result in increased water, solid waste, and 
energy impacts. We did not assess the monetary costs of these impacts 
because we expect the incremental costs will be small relative to the 
total compliance costs of the rule. You are requested to review the 
Addendum prepared in support of today's final rule for an expanded 
discussion of these impacts.

XI. The Congressional Review Act (5 U.S.C. 801 et seq., as Added by the 
Small Business Regulatory Enforcement Fairness Act of 1996)

Is Today's Rule Subject to Congressional Review?
    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A Major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2). This rule will be effective September 30, 1999.

XII. Paperwork Reduction Act (PRA), 5 U.S.C. 3501-3520

How Is the Paperwork Reduction Act Considered in Today's Rule?
    The Office of Management and Budget (OMB) has approved the 
information collection requirements (ICR) contained in this rule under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. 
and has assigned OMB control numbers 2050-0073 (``New and Amended RCRA 
Reporting and Recordkeeping Requirements for Boilers and Industrial 
Furnaces Burning Hazardous Waste'') for the RCRA provisions and 2060-
0349 (``New and Amended Reporting and Recordkeeping Requirements for 
National Emissions Standards for Hazardous Air Pollutants from 
Hazardous Waste Combustors'') for the CAA provisions.
    EPA is required under section 112(d) of the Clean Air Act to 
regulate emissions of HAPs listed in section 112(b). The requested 
information is needed as part of the overall compliance and enforcement 
program. The ICR requires that affected sources retain records of 
parameter and emissions monitoring data at facilities for a period of 
five years, which is consistent with the General Provisions to 40 CFR 
part 63 and the permit requirements under 40 CFR part 70. All sources 
subject to this rule will be required to obtain operating permits 
either through the State-approved permitting program or, if one does 
not exist, in accordance with the provisions of 40 CFR part 71, when 
promulgated. Section 3007(b) of RCRA and 40 CFR part 2, subpart B, 
which defines EPA's general policy on the public disclosure of 
information, contain provisions for confidentiality.
    The public reporting burden for this collection of information for 
the CAA provisions under OMB control number 2060-0349 is estimated to 
average 297 hours per respondent per year for an estimated 229 
respondents. The annual public reporting and record keeping burden for 
collection of information is estimated to be 67,977 hours and a cost of 
approximately $1.6 million. The total annualized capital costs and 
total annualized operation and maintenance costs associated with these 
requirements are $15,000 and nearly $1.6 million, respectively.
    The estimates for RCRA provisions under OMB control number 2050-
0073 include an annual public reporting and record keeping burden 
reduction for collection of information of 131,228 hours and a cost 
burden reduction of $4.9 million. The reductions in total annualized 
capital costs and total annualized operation and maintenance costs 
associated with these requirements are $2.1 million and $2.8 million, 
respectively. The negative cost represents the reduced burden on 25 
facilities getting out of the hazardous waste combustor universe due to 
the comparable fuels exemption. A further reduction in this RCRA 
information collection requirement burden will occur after three years 
when the combustors will start reporting under the CAA information 
collection requirements.
    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. This includes the time 
needed to review instructions; develop, acquire, install, and utilize 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    An Agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations are listed in 40 CFR part 9 and 48 CFR Chapter 15. EPA is 
amending the table in 40 CFR part 9 of currently approved ICR control 
numbers issued by OMB for various regulations to list the information 
requirements contained in this final rule.

XIII. National Technology Transfer and Advancement Act of 1995 (Pub L. 
104-113, Sec. 12(d) (15 U.S.C. 272 Note)

Was the National Technology Transfer and Advancement Act Considered?
    The rulemaking involves technical standards. Therefore, EPA 
conducted a search to identify potentially applicable voluntary 
consensus standards (VCS). However, we identified no such standards, 
and none were brought to our attention in the comments, that would 
ensure consistency throughout the regulated community. Our response-to-
comments document discusses this determination. Therefore, we have 
decided to use the Air Methods contained in part 60, appendix A.

[[Page 53026]]

    As noted in the proposed rule, the National Technology Transfer and 
Advancement Act of 1995 (NTTAA) directs EPA to use voluntary consensus 
standards in its regulatory activities unless to do so would be 
inconsistent with applicable law or otherwise impractical. Voluntary 
consensus standards are technical standards (e.g., materials 
specifications, test methods, sampling procedures, and business 
practices) that are developed or adopted by voluntary consensus 
standards bodies. The NTTAA directs EPA to provide Congress, through 
OMB, explanations when the Agency decides not to use available and 
applicable voluntary consensus standards.
    In the proposal, we discussed the manual emission test methods that 
would be required for emission tests and calibration of continuous 
emission monitors and relied heavily on the BIF methods in 40 CFR part 
266, appendix IX. On December 30, 1997, we published a NODA which in 
part questioned whether the task of determining the appropriate manual 
method tests to be used for compliance should be simplified. The stack 
sampling and analysis methods for hazardous waste combustors are under 
the current BIF and incinerator rules for compliance tests (with a few 
exceptions) that are located in SW-846. For compliance with the New 
Source Performance Standard and other air rules, methods are located in 
40 CFR part 60, appendix A. Potentially, you could be required to 
perform two identical tests, one for compliance with MACT or RCRA and 
one for compliance with other air rules, using identical test methods 
simply because one method is an ``SW-846'' method and the other an 
``air method.'' Further, the NODA stated that stack test methods 
hazardous waste combustors use for compliance should be found in one 
place to facilitate compliance. Therefore, we stated our intention to 
reference 40 CFR part 60, appendix A (Except for dioxin/furans, where 
we stated method 0023A of SW-846.), when it requires a specific stack-
sampling test method.
    Since the time of the proposal, we instituted the ``Performance-
Based Measurement System.'' This system identifies performance related 
criteria that can be used to evaluate alternative methods. Methods 
determined to contain criteria or are a ``Methods-Based Parameters'' 
method are required, and are the only methods that can be used for 
regulatory tests.
    Commenters generally supported use of the Air Methods contained in 
part 60, appendix A, or their ``SW-846'' equivalent. Furthermore, 
because these methods were used to establish the final standards 
contained in today's rulemaking, application of non approved methods 
would result in unreliable and inconsistent measurements. Therefore, 
today's rule will require the use of the Air Methods contained in part 
60, appendix A. Section 63.7 describes procedures for the use of 
alternative test methods for MACT sources. This procedure involves 
using Method 301 of part 63, appendix A, to validate an alternate test 
method and submitting the data to us. We then decide if the proposed 
method is acceptable. Absent this approval under Sec. 63.7 procedures, 
alternate methods cannot be used.
    Today's rule, by requiring the use of only part 60, appendix A 
methods (method 0023A of SW-846 for dioxin/furans) for compliance 
determinations and particulate matter continuous emission monitor 
correlations, would maintain national consistency with the selection of 
specific manual stack sampling methods. We have determined that this 
approach would facilitate ease of implementation with today's ``self 
implementing'' MACT rule. Again, alternate methods may be approved by 
the Administrator via the provisions of Sec. 63.7(f) and part Sec. 63, 
appendix A, Method 301, Field Validation or Pollutant Measurement 
Methods from Various Waste Media.

XIV. Executive Order 13084: Consultation and Coordination With Indian 
Tribal Governments (63 FR 27655)

Were Tribal Government Issues Considered?
    The requirements of section 3(b) of Executive Order 13084 do not 
apply to this rule. They apply to rules that are not required by 
statute, that significantly or uniquely affect the communities of 
Indian tribal governments, and that impose substantial direct 
compliance costs on those communities. EPA cannot issue those rules 
unless the Federal government provides the funds necessary to pay the 
direct compliance costs incurred by the tribal governments, or EPA 
consults with those governments and gives required information to OMB. 
But today's rule does not significantly or uniquely affect the 
communities of Indian tribal governments.
    For many of the same reasons described in the Unfunded Mandates 
Reform Act discussion (section VI.C above), the requirements of 
Executive Order 13084 do not apply to today's rule. Promulgation of 
today's rule is under the statutory authority of the CAA. Also, while 
Executive Order 13084 does not provide a specific gauge for determining 
whether a regulation ``significantly or uniquely affects'' an Indian 
tribal government, today's rule does not impose substantial direct 
compliance costs on tribal governments and their communities. Tribal 
communities are not predominantly located near hazardous waste 
combustion facilities, when compared with other communities throughout 
the nation. Finally, tribal governments will not be required to assume 
any permitting responsibilities associated with this final rule because 
permitting authority is voluntary for nonfederal government entities.
    Shortly after forming the regulatory workgroup for this rulemaking 
in April 1994, we looked for ways to obtain the input of state, local, 
and tribal governments into the rulemaking process. As a result, 
representatives from four State environmental agencies agreed to 
participate in the workgroup. These representatives were asked to 
consider the impacts of this rule of the state, local, and tribal 
level. These representatives served on the workgroup until Final Agency 
Review in November 1998. As members of the workgroup, they participated 
in workgroup meetings and conference calls resulting in the development 
of rulemaking issues and their solutions. They also provided written 
comments on our work products on several occasions, including the 
proposal, the May 1997 NODA, and the Final Agency Review package.
    In their comments on the proposal and subsequent notices of data 
availability, these representatives raised concerns over the following 
issues:

--Use of site-specific risk assessments under RCRA
--Continuous emissions monitors
--Manual sampling methods
--Compliance schedule
--Use of test data to establish operating limits
--Automatic waste feed cutoffs
--Performance testing schedule
--Recordkeeping requirements
--Permitting issues
--Assessment of potential costs and benefits
--Human health benefits
--Area sources
--Notification and reporting requirements
--Protectiveness of human health as required by RCRA
--Redundant requirements
--State authorization
--Public participation
--CAAA and RCRA coordination

[[Page 53027]]

--Adequate public comment
--Implementation flexibility
--Allocation of grants
--And many other technical issues

    We addressed the issues raised by these four representatives to the 
fullest extent possible in today's rule. The comments received from 
these representatives are included in the rulemaking docket, together 
with all other comments received. We highlighted and addressed some of 
these comments in today's preamble. We responded to all comments in the 
Response to Comments document, which has been made available to the 
Office of Management and Budget and is available in the docket for 
today's rule.

Part Nine: Technical Amendments to Previous Regulations

I. Changes to the June 19, 1998 ``Fast-Track'' Rule

A. Permit Streamlining Section
    Today's regulations correct a typographical error to Sec. 270.42 
Appendix I entry L(9) promulgated in the Fast-track rule. Entry L(9) 
incorrectly cited Sec. 270.42(i), whereas today's regulations correctly 
amends entry L(9) to cite Sec. 270.42(j).
B. Comparable Fuels Section
    In the June 19th rule, we explained that our methodology for 
identifying the comparable fuels specifications was to select the 
highest benchmark fuel value in our data base for each constituent (see 
63 FR at 33786). However, the results reported in the final rule--Table 
1 to Sec. 261.38--do not consistently follow our methodology. In 
several instances, the highest value was not presented in the table, as 
pointed out by commenters to the final rule. Therefore, in today's 
rule, we are amending the comparable fuels portion of the Fast-track 
rule to make necessary conforming changes to the comparable fuels 
specifications as listed in Table 1 of Sec. 261.38--Detection and 
Detection Limit Values for Comparable Fuel Specifications. Please see 
the USEPA, ``Final Technical Support Document for HWC MACT Standards, 
Volume 4'' July 1999, for a detailed discussion of the changes to Table 
1.
    In addition, because these are technical corrections (i.e. 
corrections where we made arithmetic or other inadvertent mistakes in 
applying our stated methodology for calculating the comparative fuel 
levels) we find that giving notice and opportunity for public comment 
is unnecessary within the meaning of 5 U.S.C. 553 (b) (B). In fact, the 
errors were brought to our attention by an entity that applied the 
stated methodology and derived the correct values which we are 
restoring in this amendment. (We did, however, provide actual notice of 
these intended corrections to entities we believed most interested in 
the issue, so that these entities did have an opportunity for comment 
to us.) For the same reasons, we find that there is good cause for the 
rule to take effect immediately, rather than wait 30 days. See 5 U.S.C. 
553 (d) (3). Finally, since notice and comment is unnecessary, this 
correction is not a ``rule'' for purposes of the Regulatory Flexibility 
Act (see 5 U.S.C. 601 (2)), and may take effect immediately before 
submission to Congress for review (see 5 U.S.C. 808 (2)).

List of Subjects

40 CFR Part 60

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Aluminum, Ammonium sulfate plants, Batteries, 
Beverages, Carbon monoxide, Cement industry, Coal, Copper, Dry 
cleaners, Electric power plants, Fertilizers, Fluoride, Gasoline, Glass 
and glass products, Grains, Graphic arts industry, Heaters, Household 
appliances, Insulation, Intergovernmental relations, Iron, Labeling, 
Lead, Lime, Metallic and nonmetallic mineral processing plants, Metals, 
Motor vehicles, Natural gas, Nitric acid plants, Nitrogen dioxide, 
Paper and paper products industry, Particulate matter, Paving and 
roofing materials, Petroleum, Phosphate, Plastics materials and 
synthetics, Polymers, Reporting and recordkeeping requirements, Sewage 
disposal, Steel, Sulfur oxides, Sulfuric acid plants, Tires, Urethane, 
Vinyl, Volatile organic compounds, Waste treatment and disposal, Zinc.

40 CFR Part 63

    Air pollution control, Hazardous substances, Incorporation by 
Reference, Reporting and recordkeeping requirements

40 CFR Part 260

    Administrative practice and procedure, Confidential business 
information, Environmental protection, Hazardous waste.

40 CFR Part 261

    Environmental Protection Hazardous waste, Recycling, Reporting and 
recordkeeping requirements.

40 CFR Part 264

    Air pollution control, Environmental protection, Hazardous waste, 
Insurance, Packaging and containers, Reporting and recordkeeping 
requirements, Security measures, Surety bonds.

40 CFR Part 265

    Air pollution control, Environmental protection, Hazardous waste, 
Insurance, Packaging and containers, Reporting and recordkeeping 
requirements, Security measures, Surety bonds, Water supply.

40 CFR Part 266

    Environmental protection, Energy, Hazardous waste, Recycling, 
Reporting and recordkeeping requirements.

40 CFR Part 270

    Administrative practice and procedure, Confidential business 
information, Environmental Protection Agency, Hazardous materials 
transportation, Hazardous waste, Reporting and recordkeeping 
requirements, Water pollution control, Water supply.

40 CFR Part 271

    Administrative practice and procedure, Confidential business 
information, Environmental Protection Agency, Hazardous materials 
transportation, Hazardous waste, Indians-lands, Intergovernmental 
relations, Penalties, Reporting and recordkeeping requirements, Water 
pollution control, Water supply.

    Dated: July 30, 1999.
Carol M. Browner,
Administrator.

     .For the reasons set out in the preamble, title 40 of the Code of 
Federal Regulations is amended as follows:

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

    1. The authority citation for part 60 continues to read as follows:

    Authority: 42 U.S.C. 7401-7601.

    2. Appendix A to part 60 is amended by adding a new entry for 
``Method 5I'' in numerical order to read as follows:

Appendix A--Test Methods

* * * * *
Method 5I--Determination of Low Level Particulate Matter Emissions From 
Stationary Sources
    Note: This method does not include all of the specifications 
(e.g., equipment and supplies) and procedures (e.g., sampling and 
analytical) essential to its performance. Certain information is 
contained in other EPA procedures found in this part. Therefore, to 
obtain reliable results, persons using this method should have 
experience with and a thorough knowledge of the following Methods: 
Methods 1, 2, 3, 4 and 5.


[[Page 53028]]


    1. Scope and Application.
    1.1  Analyte. Particulate matter (PM). No CAS number assigned.
    1.2  Applicability. This method is applicable for the 
determination of low level particulate matter (PM) emissions from 
stationary sources. The method is most effective for total PM 
catches of 50 mg or less. This method was initially developed for 
performing correlation of manual PM measurements to PM continuous 
emission monitoring systems (CEMS), however it is also useful for 
other low particulate concentration applications.
    1.3  Data Quality Objectives. Adherence to the requirements of 
this method will enhance the quality of the data obtained from air 
pollutant sampling methods. Method 5I requires the use of paired 
trains. Acceptance criteria for the identification of data quality 
outliers from the paired trains are provided in Section 12.2 of this 
Method.
    2. Summary of Method.
    2.1.  Description. The system setup and operation is essentially 
identical to Method 5. Particulate is withdrawn isokinetically from 
the source and collected on a 47 mm glass fiber filter maintained at 
a temperature of 120  14 deg.C (248  
25 deg.F). The PM mass is determined by gravimetric analysis after 
the removal of uncombined water. Specific measures in this procedure 
designed to improve system performance at low particulate levels 
include:

1. Improved sample handling procedures
2 Light weight sample filter assembly
3. Use of low residue grade acetone

Accuracy is improved through the minimization of systemic errors 
associated with sample handling and weighing procedures. High purity 
reagents, all glass, grease free, sample train components, and light 
weight filter assemblies and beakers, each contribute to the overall 
objective of improved precision and accuracy at low particulate 
concentrations.
    2.2  Paired Trains. This method must be performed using a paired 
train configuration. These trains may be operated as co-located 
trains (to trains operating collecting from one port) or as 
simultaneous trains (separate trains operating from different ports 
at the same time). Procedures for calculating precision of the 
paired trains are provided in Section 12.
    2.3  Detection Limit. a. Typical detection limit for manual 
particulate testing is 0.5 mg. This mass is also cited as the 
accepted weight variability limit in determination of ``constant 
weight'' as cited in Section 8.1.2 of this Method. EPA has performed 
studies to provide guidance on minimum PM catch. The minimum 
detection limit (MDL) is the minimum concentration or amount of an 
analyte that can be determined with a specified degree of confidence 
to be different from zero. We have defined the minimum or target 
catch as a concentration or amount sufficiently larger than the MDL 
to ensure that the results are reliable and repeatable. The 
particulate matter catch is the product of the average particulate 
matter concentration on a mass per volume basis and the volume of 
gas collected by the sample train. The tester can generally control 
the volume of gas collected by increasing the sampling time or to a 
lesser extent by increasing the rate at which sample is collected. 
If the tester has a reasonable estimate of the PM concentration from 
the source, the tester can ensure that the target catch is collected 
by sampling the appropriate gas volume.
    b. However, if the source has a very low particulate matter 
concentration in the stack, the volume of gas sampled may need to be 
very large which leads to unacceptably long sampling times. When 
determining compliance with an emission limit, EPA guidance has been 
that the tester does not always have to collect the target catch. 
Instead, we have suggested that the tester sample enough stack gas, 
that if the source were exactly at the level of the emission 
standard, the sample catch would equal the target catch. Thus, if at 
the end of the test the catch were smaller than the target, we could 
still conclude that the source is in compliance though we might not 
know the exact emission level. This volume of gas becomes a target 
volume that can be translated into a target sampling time by 
assuming an average sampling rate. Because the MDL forms the basis 
for our guidance on target sampling times, EPA has conducted a 
systematic laboratory study to define what is the MDL for Method 5 
and determined the Method to have a calculated practical 
quantitation limit (PQL) of 3 mg of PM and an MDL of 1 mg.
    c. Based on these results, the EPA has concluded that for PM 
testing, the target catch must be no less than 3 mg. Those sample 
catches between 1 mg and 3 mg are between the detection limit and 
the limit of quantitation. If a tester uses the target catch to 
estimate a target sampling time that results in sample catches that 
are less than 3 mg, you should not automatically reject the results. 
If the tester calculated the target sampling time as described above 
by assuming that the source was at the level of the emission limit, 
the results would still be valid for determining that the source was 
in compliance. For purposes other than determining compliance, 
results should be divided into two categories--those that fall 
between 3 mg and 1 mg and those that are below 1 mg. A sample catch 
between 1 and 3 mg may be used for such purposes as calculating 
emission rates with the understanding that the resulting emission 
rates can have a high degree of uncertainty. Results of less than 1 
mg should not be used for calculating emission rates or pollutant 
concentrations.
    d. When collecting small catches such as 3 mg, bias becomes an 
important issue. Source testers must use extreme caution to reach 
the PQL of 3 mg by assuring that sampling probes are very clean 
(perhaps confirmed by low blank weights) before use in the field. 
They should also use low tare weight sample containers, and 
establish a well-controlled balance room to weigh the samples.
    3. Definitions.
    3.1  Light Weight Filter Housing. A smaller housing that allows 
the entire filtering system to be weighed before and after sample 
collection. (See. 6.1.3)
    3.2  Paired Train. Sample systems trains may be operated as co-
located trains (two sample probes attached to each other in the same 
port) or as simultaneous trains (two separate trains operating from 
different ports at the same time).
    4. Interferences.
    a. There are numerous potential interferents that may be 
encountered during performance of Method 5I sampling and analyses. 
This Method should be considered more sensitive to the normal 
interferents typically encountered during particulate testing 
because of the low level concentrations of the flue gas stream being 
sampled.
    b. Care must be taken to minimize field contamination, 
especially to the filter housing since the entire unit is weighed 
(not just the filter media). Care must also be taken to ensure that 
no sample is lost during the sampling process (such as during port 
changes, removal of the filter assemblies from the probes, etc.).
    c. Balance room conditions are a source of concern for analysis 
of the low level samples. Relative humidity, ambient temperatures 
variations, air draft, vibrations and even barometric pressure can 
affect consistent reproducible measurements of the sample media. 
Ideally, the same analyst who performs the tare weights should 
perform the final weights to minimize the effects of procedural 
differences specific to the analysts.
    d. Attention must also be provided to weighing artifacts caused 
by electrostatic charges which may have to be discharged or 
neutralized prior to sample analysis. Static charge can affect 
consistent and reliable gravimetric readings in low humidity 
environments. Method 5I recommends a relative humidity of less than 
50 percent in the weighing room environment used for sample 
analyses. However, lower humidity may be encountered or required to 
address sample precision problems. Low humidity conditions can 
increase the effects of static charge.
    e. Other interferences associated with typical Method 5 testing 
(sulfates, acid gases, etc.) are also applicable to Method 5I.
    5. Safety.
    Disclaimer. This method may involve hazardous materials, 
operations, and equipment. This test method may not address all of 
the safety concerns associated with its use. It is the 
responsibility of the user to establish appropriate safety and 
health practices and to determine the applicability and observe all 
regulatory limitations before using this method.
    6. Equipment and Supplies.
    6.1  Sample Collection Equipment and Supplies. The sample train 
is nearly identical in configuration to the train depicted in Figure 
5-1 of Method 5. The primary difference in the sample trains is the 
lightweight Method 5I filter assembly that attaches directly to the 
exit to the probe. Other exceptions and additions specific to Method 
5I include:
    6.1.1  Probe Nozzle. Same as Method 5, with the exception that 
it must be constructed of borosilicate or quartz glass tubing.
    6.1.2  Probe Liner. Same as Method 5, with the exception that it 
must be

[[Page 53029]]

constructed of borosilicate or quartz glass tubing.
    6.1.3  Filter Holder. The filter holder is constructed of 
borosilicate or quartz glass front cover designed to hold a 47-mm 
glass fiber filter, with a wafer thin stainless steel (SS) filter 
support, a silicone rubber or Viton O-ring, and Teflon tape seal. 
This holder design will provide a positive seal against leakage from 
the outside or around the filter. The filter holder assembly fits 
into a SS filter holder and attaches directly to the outlet of the 
probe. The tare weight of the filter, borosilicate or quartz glass 
holder, SS filter support, O-ring and Teflon tape seal generally 
will not exceed approximately 35 grams. The filter holder is 
designed to use a 47-mm glass fiber filter meeting the quality 
criteria in of Method 5. These units are commercially available from 
several source testing equipment vendors. Once the filter holder has 
been assembled, desiccated and tared, protect it from external 
sources of contamination by covering the front socket with a ground 
glass plug. Secure the plug with an impinger clamp or other item 
that will ensure a leak-free fitting.
    6.2  Sample Recovery Equipment and Supplies. Same as Method 5, 
with the following exceptions:
    6.2.1  Probe-Liner and Probe-Nozzle Brushes. Teflon 
or nylon bristle brushes with stainless steel wire handles, should 
be used to clean the probe. The probe brush must have extensions (at 
least as long as the probe) of Teflon, nylon or similarly inert 
material. The brushes must be properly sized and shaped for brushing 
out the probe liner and nozzle.
    6.2.2  Wash Bottles. Two Teflon wash bottles are recommended 
however, polyethylene wash bottles may be used at the option of the 
tester. Acetone should not be stored in polyethylene bottles for 
longer than one month.
    6.2.3  Filter Assembly Transport. A system should be employed to 
minimize contamination of the filter assemblies during transport to 
and from the field test location. A carrying case or packet with 
clean compartments of sufficient size to accommodate each filter 
assembly can be used. This system should have an air tight seal to 
further minimize contamination during transport to and from the 
field.
    6.3  Analysis Equipment and Supplies. Same as Method 5, with the 
following exception:
    6.3.1  Lightweight Beaker Liner. Teflon or other lightweight 
beaker liners are used for the analysis of the probe and nozzle 
rinses. These light weight liners are used in place of the 
borosilicate glass beakers typically used for the Method 5 weighings 
in order to improve sample analytical precision.
    6.3.2  Anti-static Treatment. Commercially available gaseous 
anti-static rinses are recommended for low humidity situations that 
contribute to static charge problems.
    7. Reagents and Standards.
    7.1  Sampling Reagents. The reagents used in sampling are the 
same as Method 5 with the following exceptions:
    7.1.1  Filters. The quality specifications for the filters are 
identical to those cited for Method 5. The only difference is the 
filter diameter of 47 millimeters.
    7.1.2  Stopcock Grease. Stopcock grease cannot be used with this 
sampling train. We recommend that the sampling train be assembled 
with glass joints containing O-ring seals or screw-on connectors, or 
similar.
    7.1.3  Acetone. Low residue type acetone, 0.001 
percent residue, purchased in glass bottles is used for the recovery 
of particulate matter from the probe and nozzle. Acetone from metal 
containers generally has a high residue blank and should not be 
used. Sometimes, suppliers transfer acetone to glass bottles from 
metal containers; thus, acetone blanks must be run prior to field 
use and only acetone with low blank values (0.001 percent 
residue, as specified by the manufacturer) must be used. Acetone 
blank correction is not allowed for this method; therefore, it is 
critical that high purity reagents be purchased and verified prior 
to use.
    7.1.4  Gloves. Disposable, powder-free, latex surgical gloves, 
or their equivalent are used at all times when handling the filter 
housings or performing sample recovery.
    7.2  Standards. There are no applicable standards or audit 
samples commercially available for Method 5I analyses.
    8. Sample Collection, Preservation, Storage, and Transport.
    8.1  Pretest Preparation. Same as Method 5 with several 
exceptions specific to filter assembly and weighing.
    8.1.1  Filter Assembly. Uniquely identify each filter support 
before loading filters into the holder assembly. This can be done 
with an engraving tool or a permanent marker. Use powder free latex 
surgical gloves whenever handling the filter holder assemblies. 
Place the O-ring on the back of the filter housing in the O-ring 
groove. Place a 47 mm glass fiber filter on the O-ring with the face 
down. Place a stainless steel filter holder against the back of the 
filter. Carefully wrap 5 mm (\1/4\ inch) wide Teflon'' tape one 
timearound the outside of the filter holder overlapping the 
stainless steel filter support by approximately 2.5 mm (\1/8\ inch). 
Gently brush the Teflon tape down on the back of the stainless steel 
filter support. Store the filter assemblies in their transport case 
until time for weighing or field use.
    8.1.2  Filter Weighing Procedures. a. Desiccate the entire 
filter holder assemblies at 20  5.6 deg.C (68 
 10 deg.F) and ambient pressure for at least 24 hours. 
Weigh at intervals of at least 6 hours to a constant weight, i.e., 
0.5 mg change from previous weighing. Record the results to the 
nearest 0.1 mg. During each weighing, the filter holder assemblies 
must not be exposed to the laboratory atmosphere for a period 
greater than 2 minutes and a relative humidity above 50 percent. 
Lower relative humidity may be required in order to improve 
analytical precision. However, low humidity conditions increase 
static charge to the sample media.
    b. Alternatively (unless otherwise specified by the 
Administrator), the filters holder assemblies may be oven dried at 
105 deg.C (220 deg.F) for a minimum of 2 hours, desiccated for 2 
hours, and weighed. The procedure used for the tare weigh must also 
be used for the final weight determination.
    c. Experience has shown that weighing uncertainties are not only 
related to the balance performance but to the entire weighing 
procedure. Therefore, before performing any measurement, establish 
and follow standard operating procedures, taking into account the 
sampling equipment and filters to be used.
    8.2  Preliminary Determinations. Select the sampling site, 
traverse points, probe nozzle, and probe length as specified in 
Method 5.
    8.3  Preparation of Sampling Train. Same as Method 5, Section 
8.3, with the following exception: During preparation and assembly 
of the sampling train, keep all openings where contamination can 
occur covered until justbefore assembly or until sampling is about 
to begin. Using gloves, place a labeled (identified) and weighed 
filter holder assembly into the stainless steel holder. Then place 
this whole unit in the Method 5 hot box, and attach it to the probe. 
Do not use stopcock grease.
    8.4  Leak-Check Procedures. Same as Method 5.
    8.5  Sampling Train Operation.
    8.5.1.  Operation. Operate the sampling train in a manner 
consistent with those described in Methods 1, 2, 4 and 5 in terms of 
the number of sample points and minimum time per point. The sample 
rate and total gas volume should be adjusted based on estimated 
grain loading of the source being characterized. The total sampling 
time must be a function of the estimated mass of particulate to be 
collected for the run. Targeted mass to be collected in a typical 
Method 5I sample train should be on the order of 10 to 20 mg. Method 
5I is most appropriate for total collected masses of less than 50 
milligrams, however, there is not an exact particulate loading 
cutoff, and it is likely that some runs may exceed 50 mg. Exceeding 
50 mg (or less than 10 mg) for the sample mass does not necessarily 
justify invalidating a sample run if all other Method criteria are 
met.
    8.5.2  Paired Train. This Method requires PM samples be 
collected with paired trains.
    8.5.2.1  It is important that the systems be operated truly 
simultaneously. This implies that both sample systems start and stop 
at the same times. This also means that if one sample system is 
stopped during the run, the other sample systems must also be 
stopped until the cause has been corrected.
    8.5.2.2  Care should be taken to maintain the filter box 
temperature of the paired trains as close as possible to the Method 
required temperature of 120  14 deg.C (248  
25 deg.F). If separate ovens are being used for simultaneously 
operated trains, it is recommended that the oven temperature of each 
train be maintained within  14 deg.C ( 
25 deg.F) of each other.
    8.5.2.3  The nozzles for paired trains need not be identically 
sized.
    8.5.2.4  Co-located sample nozzles must be within the same plane 
perpendicular to the gas flow. Co-located nozzles and pitot 
assemblies should be within a 6.0 cm  x  6.0 cm square (as cited for 
a quadruple train in Reference Method 301).
    8.5.3  Duplicate gas samples for molecular weight determination 
need not be collected.

[[Page 53030]]

    8.6  Sample Recovery. Same as Method 5 with several exceptions 
specific to the filter housing.
    8.6.1  Before moving the sampling train to the cleanup site, 
remove the probe from the train and seal the nozzle inlet and outlet 
of the probe. Be careful not to lose any condensate that might be 
present. Cap the filter inlet using a standard ground glass plug and 
secure the cap with an impinger clamp. Remove the umbilical cord 
from the last impinger and cap the impinger. If a flexible line is 
used between the first impinger condenser and the filter holder, 
disconnect the line at the filter holder and let any condensed water 
or liquid drain into the impingers or condenser.
    8.6.2  Transfer the probe and filter-impinger assembly to the 
cleanup area. This area must be clean and protected from the wind so 
that the possibility of losing any of the sample will be minimized.
    8.6.3  Inspect the train prior to and during disassembly and 
note any abnormal conditions such as particulate color, filter 
loading, impinger liquid color, etc.
    8.6.4  Container No. 1, Filter Assembly. Carefully remove the 
cooled filter holder assembly from the Method 5 hot box and place it 
in the transport case. Use a pair of clean gloves to handle the 
filter holder assembly.
    8.6.5  Container No. 2, Probe Nozzle and Probe Liner Rinse. 
Rinse the probe and nozzle components with acetone. Be certain that 
the probe and nozzle brushes have been thoroughly rinsed prior to 
use as they can be a source of contamination.
    8.6.6  All Other Train Components. (Impingers) Same as Method 5.
    8.7  Sample Storage and Transport. Whenever possible, containers 
should be shipped in such a way that they remain upright at all 
times. All appropriate dangerous goods shipping requirements must be 
observed since acetone is a flammable liquid.
    9. Quality Control.
    9.1  Miscellaneous Field Quality Control Measures.
    9.1.1  A quality control (QC) check of the volume metering 
system at the field site is suggested before collecting the sample 
using the procedures in Method 5, Section 4.4.1.
    9.1.2  All other quality control checks outlined in Methods 1, 
2, 4 and 5 also apply to Method 5I. This includes procedures such as 
leak-checks, equipment calibration checks, and independent checks of 
field data sheets for reasonableness and completeness.
    9.2  Quality Control Samples.
    9.2.1  Required QC Sample. A laboratory reagent blank must be 
collected and analyzed for each lot of acetone used for a field 
program to confirm that it is of suitable purity. The particulate 
samples cannot be blank corrected.
    9.2.2  Recommended QC Samples. These samples may be collected 
and archived for future analyses.
    9.2.2.1  A field reagent blank is a recommended QC sample 
collected from a portion of the acetone used for cleanup of the 
probe and nozzle. Take 100 ml of this acetone directly from the wash 
bottle being used and place it in a glass sample container labeled 
``field acetone reagent blank.'' At least one field reagent blank is 
recommended for every five runs completed. The field reagent blank 
samples demonstrate the purity of the acetone was maintained 
throughout the program.
    9.2.2.2  A field bias blank train is a recommended QC sample. 
This sample is collected by recovering a probe and filter assembly 
that has been assembled, taken to the sample location, leak checked, 
heated, allowed to sit at the sample location for a similar duration 
of time as a regular sample run, leak-checked again, and then 
recovered in the same manner as a regular sample. Field bias blanks 
are not a Method requirement, however, they are recommended and are 
very useful for identifying sources of contamination in emission 
testing samples. Field bias blank train results greater than 5 times 
the method detection limit may be considered problematic.
    10.  Calibration and Standardization Same as Method 5, Section 
5.
    11. Analytical Procedures.
    11.1  Analysis. Same as Method 5, Sections 11.1--11.2.4, with 
the following exceptions:
    11.1.1  Container No. 1. Same as Method 5, Section 11.2.1, with 
the following exception: Use disposable gloves to remove each of the 
filter holder assemblies from the desiccator, transport container, 
or sample oven (after appropriate cooling).
    11.1.2  Container No. 2. Same as Method 5, Section 11.2.2, with 
the following exception: It is recommended that the contents of 
Container No. 2 be transferred to a 250 ml beaker with a Teflon 
liner or similar container that has a minimal tare weight before 
bringing to dryness.
    12. Data Analysis and Calculations.
    12.1  Particulate Emissions. The analytical results cannot be 
blank corrected for residual acetone found in any of the blanks. All 
other sample calculations are identical to Method 5.
    12.2  Paired Trains Outliers. a. Outliers are identified through 
the determination of precision and any systemic bias of the paired 
trains. Data that do not meet this criteria should be flagged as a 
data quality problem. The primary reason for performing dual train 
sampling is to generate information to quantify the precision of the 
Reference Method data. The relative standard deviation (RSD) of 
paired data is the parameter used to quantify data precision. RSD 
for two simultaneously gathered data points is determined according 
to: 
[GRAPHIC] [TIFF OMITTED] TR30SE99.008

where, Ca and Cb are concentration values determined from trains A 
and B respectively. For RSD calculation, the concentration units are 
unimportant so long as they are consistent.
    b. A minimum precision criteria for Reference Method PM data is 
that RSD for any data pair must be less than 10% as long as the mean 
PM concentration is greater than 10 mg/unit volume. If the mean PM 
concentration is less than 10 mg/unit volume higher RSD values are 
acceptable. At mean PM concentration of 1 mg/unit volume acceptable 
RSD for paired trains is 25%. Between 1 and 10 mg/unit volume 
acceptable RSD criteria should be linearly scaled from 25% to 10%. 
Pairs of manual method data exceeding these RSD criteria should be 
eliminated from the data set used to develop a PM CEMS correlation 
or to assess RCA.
    13. Method Performance. [Reserved]
    14. Pollution Prevention. [Reserved]
    15. Waste Management. [Reserved]
    16. Alternative Procedures. Same as Method 5.
    17. Bibliography. Same as Method 5.
    18. Tables, Diagrams, Flowcharts and Validation Data. Figure 5I-
1 is a schematic of the sample train.

BILLING CODE 6560-50-P 

[[Page 53031]]

[GRAPHIC] [TIFF OMITTED] TR30SE99.009



BILLING CODE 6560-50-C

[[Page 53032]]

    3. Appendix B to part 60 is amended by adding Performance 
Specifications 4B and 8A in numerical order to read as follows:

Appendix B--Performance Specifications

* * * * *
Performance Specification 4B---Specifications and test procedures 
for carbon monoxide and oxygen continuous monitoring systems in 
stationary sources

a. Applicability and Principle

    1.1  Applicability. a. This specification is to be used for 
evaluating the acceptability of carbon monoxide (CO) and oxygen 
(O2) continuous emission monitoring systems (CEMS) at the 
time of or soon after installation and whenever specified in the 
regulations. The CEMS may include, for certain stationary sources, 
(a) flow monitoring equipment to allow measurement of the dry volume 
of stack effluent sampled, and (b) an automatic sampling system.
    b. This specification is not designed to evaluate the installed 
CEMS' performance over an extended period of time nor does it 
identify specific calibration techniques and auxiliary procedures to 
assess the CEMS' performance. The source owner or operator, however, 
is responsible to properly calibrate, maintain, and operate the 
CEMS. To evaluate the CEMS' performance, the Administrator may 
require, under section 114 of the Act, the operator to conduct CEMS 
performance evaluations at times other than the initial test.
    c. The definitions, installation and measurement location 
specifications, test procedures, data reduction procedures, 
reporting requirements, and bibliography are the same as in PS 3 
(for O2) and PS 4A (for CO) except as otherwise noted 
below.
    1.2  Principle. Installation and measurement location 
specifications, performance specifications, test procedures, and 
data reduction procedures are included in this specification. 
Reference method tests, calibration error tests, calibration drift 
tests, and interferant tests are conducted to determine conformance 
of the CEMS with the specification.

b. Definitions

    2.1  Continuous Emission Monitoring System (CEMS). This 
definition is the same as PS 2 Section 2.1 with the following 
addition. A continuous monitor is one in which the sample to be 
analyzed passes the measurement section of the analyzer without 
interruption.
    2.2  Response Time. The time interval between the start of a 
step change in the system input and when the pollutant analyzer 
output reaches 95 percent of the final value.
    2.3  Calibration Error (CE). The difference between the 
concentration indicated by the CEMS and the known concentration 
generated by a calibration source when the entire CEMS, including 
the sampling interface is challenged. A CE test procedure is 
performed to document the accuracy and linearity of the CEMS over 
the entire measurement range.

3. Installation and Measurement Location Specifications

    3.1  The CEMS Installation and Measurement Location. This 
specification is the same as PS 2 Section 3.1 with the following 
additions. Both the CO and O2 monitors should be 
installed at the same general location. If this is not possible, 
they may be installed at different locations if the effluent gases 
at both sample locations are not stratified and there is no in-
leakage of air between sampling locations.
    3.1.1  Measurement Location. Same as PS 2 Section 3.1.1.
    3.1.2  Point CEMS. The measurement point should be within or 
centrally located over the centroidal area of the stack or duct 
cross section.
    3.1.3  Path CEMS. The effective measurement path should: (1) 
Have at least 70 percent of the path within the inner 50 percent of 
the stack or duct cross sectional area, or (2) be centrally located 
over any part of the centroidal area.
    3.2  Reference Method (RM) Measurement Location and Traverse 
Points. This specification is the same as PS 2 Section 3.2 with the 
following additions. When pollutant concentration changes are due 
solely to diluent leakage and CO and O2 are 
simultaneously measured at the same location, one half diameter may 
be used in place of two equivalent diameters.
    3.3  Stratification Test Procedure. Stratification is defined as 
the difference in excess of 10 percent between the average 
concentration in the duct or stack and the concentration at any 
point more than 1.0 meter from the duct or stack wall. To determine 
whether effluent stratification exists, a dual probe system should 
be used to determine the average effluent concentration while 
measurements at each traverse point are being made. One probe, 
located at the stack or duct centroid, is used as a stationary 
reference point to indicate change in the effluent concentration 
over time. The second probe is used for sampling at the traverse 
points specified in Method 1 (40 CFR part 60 appendix A). The 
monitoring system samples sequentially at the reference and traverse 
points throughout the testing period for five minutes at each point.

d. Performance and Equipment Specifications

    4.1  Data Recorder Scale. For O2, same as specified 
in PS 3, except that the span must be 25 percent. The span of the 
O2 may be higher if the O2 concentration at 
the sampling point can be greater than 25 percent. For CO, same as 
specified in PS 4A, except that the low-range span must be 200 ppm 
and the high range span must be 3000 ppm. In addition, the scale for 
both CEMS must record all readings within a measurement range with a 
resolution of 0.5 percent.
    4.2  Calibration Drift. For O2, same as specified in 
PS 3. For CO, the same as specified in PS 4A except that the CEMS 
calibration must not drift from the reference value of the 
calibration standard by more than 3 percent of the span value on 
either the high or low range.
    4.3  Relative Accuracy (RA). For O2, same as 
specified in PS 3. For CO, the same as specified in PS 4A.
    4.4  Calibration Error (CE). The mean difference between the 
CEMS and reference values at all three test points (see Table I) 
must be no greater than 5 percent of span value for CO monitors and 
0.5 percent for O2 monitors.
    4.5  Response Time. The response time for the CO or 
O2 monitor must not exceed 2 minutes.

e. Performance Specification Test Procedure

    5.1  Calibration Error Test and Response Time Test Periods. 
Conduct the CE and response time tests during the CD test period.

F. The CEMS Calibration Drift and Response Time Test Procedures

    The response time test procedure is given in PS 4A, and must be 
carried out for both the CO and O2 monitors.

7. Relative Accuracy and Calibration Error Test Procedures

    7.1  Calibration Error Test Procedure. Challenge each monitor 
(both low and high range CO and O2) with zero gas and EPA 
Protocol 1 cylinder gases at three measurement points within the 
ranges specified in Table I.

             Table I. Calibration Error Concentration Ranges
------------------------------------------------------------------------
                                      CO Low
         Measurement point             range       CO High      O2 (%)
                                       (ppm)     range (ppm)
------------------------------------------------------------------------
1.................................    0-40        0-600           0-2
2.................................   60-80      900-1200         8-10
3.................................  140-160     2100-2400       14-16
------------------------------------------------------------------------

Operate each monitor in its normal sampling mode as nearly as 
possible. The calibration gas must be injected into the sample 
system as close to the sampling probe outlet as practical and should 
pass through all CEMS components used during normal sampling. 
Challenge the CEMS three non-consecutive times at each measurement 
point and record the responses. The duration of each gas

[[Page 53033]]

injection should be sufficient to ensure that the CEMS surfaces are 
conditioned.
    7.1.1  Calculations. Summarize the results on a data sheet. 
Average the differences between the instrument response and the 
certified cylinder gas value for each gas. Calculate the CE results 
according to: 
[GRAPHIC] [TIFF OMITTED] TR30SE99.010

where d is the mean difference between the CEMS response and the 
known reference concentration and FS is the span value.
    7.2  Relative Accuracy Test Procedure. Follow the RA test 
procedures in PS 3 (for O2) section 3 and PS 4A (for CO) 
section 4.
    7.3  Alternative RA Procedure. Under some operating conditions, 
it may not be possible to obtain meaningful results using the RA 
test procedure. This includes conditions where consistent, very low 
CO emission or low CO emissions interrupted periodically by short 
duration, high level spikes are observed. It may be appropriate in 
these circumstances to waive the RA test and substitute the 
following procedure.
    Conduct a complete CEMS status check following the 
manufacturer's written instructions. The check should include 
operation of the light source, signal receiver, timing mechanism 
functions, data acquisition and data reduction functions, data 
recorders, mechanically operated functions, sample filters, sample 
line heaters, moisture traps, and other related functions of the 
CEMS, as applicable. All parts of the CEMS must be functioning 
properly before the RA requirement can be waived. The instrument 
must also successfully passed the CE and CD specifications. 
Substitution of the alternate procedure requires approval of the 
Regional Administrator.

8. Bibliography

    1. 40 CFR Part 266, Appendix IX, Section 2, ``Performance 
Specifications for Continuous Emission Monitoring Systems.''
* * * * *
Performance Specification 8A--Specifications and test procedures for 
total hydrocarbon continuous monitoring systems in stationary 
sources

1. Applicability and Principle

    1.1  Applicability. These performance specifications apply to 
hydrocarbon (HC) continuous emission monitoring systems (CEMS) 
installed on stationary sources. The specifications include 
procedures which are intended to be used to evaluate the 
acceptability of the CEMS at the time of its installation or 
whenever specified in regulations or permits. The procedures are not 
designed to evaluate CEMS performance over an extended period of 
time. The source owner or operator is responsible for the proper 
calibration, maintenance, and operation of the CEMS at all times.
    1.2  Principle. A gas sample is extracted from the source 
through a heated sample line and heated filter to a flame ionization 
detector (FID). Results are reported as volume concentration 
equivalents of propane. Installation and measurement location 
specifications, performance and equipment specifications, test and 
data reduction procedures, and brief quality assurance guidelines 
are included in the specifications. Calibration drift, calibration 
error, and response time tests are conducted to determine 
conformance of the CEMS with the specifications.

2. Definitions

    2.1  Continuous Emission Monitoring System (CEMS). The total 
equipment used to acquire data, which includes sample extraction and 
transport hardware, analyzer, data recording and processing 
hardware, and software. The system consists of the following major 
subsystems:
    2.1.1  Sample Interface. That portion of the system that is used 
for one or more of the following: Sample acquisition, sample 
transportation, sample conditioning, or protection of the analyzer 
from the effects of the stack effluent.
    2.1.2  Organic Analyzer. That portion of the system that senses 
organic concentration and generates an output proportional to the 
gas concentration.
    2.1.3  Data Recorder. That portion of the system that records a 
permanent record of the measurement values. The data recorder may 
include automatic data reduction capabilities.
    2.2  Instrument Measurement Range. The difference between the 
minimum and maximum concentration that can be measured by a specific 
instrument. The minimum is often stated or assumed to be zero and 
the range expressed only as the maximum.
    2.3  Span or Span Value. Full scale instrument measurement 
range. The span value must be documented by the CEMS manufacturer 
with laboratory data.
    2.4  Calibration Gas. A known concentration of a gas in an 
appropriate diluent gas.
    2.5  Calibration Drift (CD). The difference in the CEMS output 
readings from the established reference value after a stated period 
of operation during which no unscheduled maintenance, repair, or 
adjustment takes place. A CD test is performed to demonstrate the 
stability of the CEMS calibration over time.
    2.6  Response Time. The time interval between the start of a 
step change in the system input (e.g., change of calibration gas) 
and the time when the data recorder displays 95 percent of the final 
value.
    2.7  Accuracy. A measurement of agreement between a measured 
value and an accepted or true value, expressed as the percentage 
difference between the true and measured values relative to the true 
value. For these performance specifications, accuracy is checked by 
conducting a calibration error (CE) test.
    2.8  Calibration Error (CE). The difference between the 
concentration indicated by the CEMS and the known concentration of 
the cylinder gas. A CE test procedure is performed to document the 
accuracy and linearity of the monitoring equipment over the entire 
measurement range.
    2.9  Performance Specification Test (PST) Period. The period 
during which CD, CE, and response time tests are conducted.
    2.10  Centroidal Area. A concentric area that is geometrically 
similar to the stack or duct cross section and is no greater than 1 
percent of the stack or duct cross-sectional area.

3. Installation and Measurement Location Specifications

    3.1  CEMS Installation and Measurement Locations. The CEMS must 
be installed in a location in which measurements representative of 
the source's emissions can be obtained. The optimum location of the 
sample interface for the CEMS is determined by a number of factors, 
including ease of access for calibration and maintenance, the degree 
to which sample conditioning will be required, the degree to which 
it represents total emissions, and the degree to which it represents 
the combustion situation in the firebox (where applicable). The 
location should be as free from in-leakage influences as possible 
and reasonably free from severe flow disturbances. The sample 
location should be at least two equivalent duct diameters downstream 
from the nearest control device, point of pollutant generation, or 
other point at which a change in the pollutant concentration or 
emission rate occurs and at least 0.5 diameter upstream from the 
exhaust or control device. The equivalent duct diameter is 
calculated as per 40 CFR part 60, appendix A, method 1, section 2.1. 
If these criteria are not achievable or if the location is otherwise 
less than optimum, the possibility of stratification should be 
investigated as described in section 3.2. The measurement point must 
be within the centroidal area of the stack or duct cross section.
    3.2  Stratification Test Procedure. Stratification is defined as 
a difference in excess of 10 percent between the average 
concentration in the duct or stack and the concentration at any 
point more than 1.0 meter from the duct or stack wall. To determine 
whether effluent stratification exists, a dual probe system should 
be used to determine the average effluent concentration while 
measurements at each traverse point are being made. One probe, 
located at the stack or duct centroid, is used as a stationary 
reference point to indicate the change in effluent concentration 
over time. The second probe is used for sampling at the traverse 
points specified in 40 CFR part 60 appendix A, method 1. The 
monitoring system samples sequentially at the reference and traverse 
points throughout the testing period for five minutes at each point.

4. CEMS Performance and Equipment Specifications

    If this method is applied in highly explosive areas, caution and 
care must be exercised in choice of equipment and installation.
    4.1  Flame Ionization Detector (FID) Analyzer. A heated FID 
analyzer capable of meeting or exceeding the requirements of these 
specifications. Heated systems must maintain the temperature of the 
sample gas between 150  deg.C (300  deg.F) and 175  deg.C (350 
deg.F) throughout the system. This requires all system components 
such as the probe, calibration valve, filter, sample lines, pump, 
and the FID to be kept heated at all times such that no moisture is 
condensed out of the

[[Page 53034]]

system. The essential components of the measurement system are 
described below:
    4.1.1  Sample Probe. Stainless steel, or equivalent, to collect 
a gas sample from the centroidal area of the stack cross-section.
    4.1.2  Sample Line. Stainless steel or Teflon tubing to 
transport the sample to the analyzer.

    Note: Mention of trade names or specific products does not 
constitute endorsement by the Environmental Protection Agency.

    4.1.3  Calibration Valve Assembly. A heated three-way valve 
assembly to direct the zero and calibration gases to the analyzer is 
recommended. Other methods, such as quick-connect lines, to route 
calibration gas to the analyzers are applicable.
    4.1.4  Particulate Filter. An in-stack or out-of-stack sintered 
stainless steel filter is recommended if exhaust gas particulate 
loading is significant. An out-of-stack filter must be heated.
    4.1.5  Fuel. The fuel specified by the manufacturer (e.g., 40 
percent hydrogen/60 percent helium, 40 percent hydrogen/60 percent 
nitrogen gas mixtures, or pure hydrogen) should be used.
    4.1.6  Zero Gas. High purity air with less than 0.1 parts per 
million by volume (ppm) HC as methane or carbon equivalent or less 
than 0.1 percent of the span value, whichever is greater.
    4.1.7  Calibration Gases. Appropriate concentrations of propane 
gas (in air or nitrogen). Preparation of the calibration gases 
should be done according to the procedures in EPA Protocol 1. In 
addition, the manufacturer of the cylinder gas should provide a 
recommended shelf life for each calibration gas cylinder over which 
the concentration does not change by more than 2 percent 
from the certified value.
    4.2  CEMS Span Value. 100 ppm propane. The span value must be 
documented by the CEMS manufacturer with laboratory data.
    4.3  Daily Calibration Gas Values. The owner or operator must 
choose calibration gas concentrations that include zero and high-
level calibration values.
    4.3.1  The zero level may be between zero and 0.1 ppm (zero and 
0.1 percent of the span value).
    4.3.2  The high-level concentration must be between 50 and 90 
ppm (50 and 90 percent of the span value).
    4.4  Data Recorder Scale. The strip chart recorder, computer, or 
digital recorder must be capable of recording all readings within 
the CEMS' measurement range and must have a resolution of 0.5 ppm 
(0.5 percent of span value).
    4.5  Response Time. The response time for the CEMS must not 
exceed 2 minutes to achieve 95 percent of the final stable value.
    4.6  Calibration Drift. The CEMS must allow the determination of 
CD at the zero and high-level values. The CEMS calibration response 
must not differ by more than 3 ppm (3 
percent of the span value) after each 24-hour period of the 7-day 
test at both zero and high levels.
    4.7  Calibration Error. The mean difference between the CEMS and 
reference values at all three test points listed below must be no 
greater than 5 ppm (5 percent of the span value).
    4.7.1  Zero Level. Zero to 0.1 ppm (0 to 0.1 percent of span 
value).
    4.7.2  Mid-Level. 30 to 40 ppm (30 to 40 percent of span value).
    4.7.3  High-Level. 70 to 80 ppm (70 to 80 percent of span 
value).
    4.8  Measurement and Recording Frequency. The sample to be 
analyzed must pass through the measurement section of the analyzer 
without interruption. The detector must measure the sample 
concentration at least once every 15 seconds. An average emission 
rate must be computed and recorded at least once every 60 seconds.
    4.9  Hourly Rolling Average Calculation. The CEMS must calculate 
every minute an hourly rolling average, which is the arithmetic mean 
of the 60 most recent 1-minute average values.
    4.10  Retest. If the CEMS produces results within the specified 
criteria, the test is successful. If the CEMS does not meet one or 
more of the criteria, necessary corrections must be made and the 
performance tests repeated.

5. Performance Specification Test (PST) Periods

    5.1  Pretest Preparation Period. Install the CEMS, prepare the 
PTM test site according to the specifications in section 3, and 
prepare the CEMS for operation and calibration according to the 
manufacturer's written instructions. A pretest conditioning period 
similar to that of the 7-day CD test is recommended to verify the 
operational status of the CEMS.
    5.2  Calibration Drift Test Period. While the facility is 
operating under normal conditions, determine the magnitude of the CD 
at 24-hour intervals for seven consecutive days according to the 
procedure given in section 6.1. All CD determinations must be made 
following a 24-hour period during which no unscheduled maintenance, 
repair, or adjustment takes place. If the combustion unit is taken 
out of service during the test period, record the onset and duration 
of the downtime and continue the CD test when the unit resumes 
operation.
    5.3  Calibration Error Test and Response Time Test Periods. 
Conduct the CE and response time tests during the CD test period.

6. Performance Specification Test Procedures

    6.1  Relative Accuracy Test Audit (RATA) and Absolute 
Calibration Audits (ACA). The test procedures described in this 
section are in lieu of a RATA and ACA.
    6.2  Calibration Drift Test.
    6.2.1  Sampling Strategy. Conduct the CD test at 24-hour 
intervals for seven consecutive days using calibration gases at the 
two daily concentration levels specified in section 4.3. Introduce 
the two calibration gases into the sampling system as close to the 
sampling probe outlet as practical. The gas must pass through all 
CEM components used during normal sampling. If periodic automatic or 
manual adjustments are made to the CEMS zero and calibration 
settings, conduct the CD test immediately before these adjustments, 
or conduct it in such a way that the CD can be determined. Record 
the CEMS response and subtract this value from the reference 
(calibration gas) value. To meet the specification, none of the 
differences may exceed 3 percent of the span of the CEM.
    6.2.2  Calculations. Summarize the results on a data sheet. An 
example is shown in Figure 1. Calculate the differences between the 
CEMS responses and the reference values.
    6.3  Response Time. The entire system including sample 
extraction and transport, sample conditioning, gas analyses, and the 
data recording is checked with this procedure.
    6.3.1  Introduce the calibration gases at the probe as near to 
the sample location as possible. Introduce the zero gas into the 
system. When the system output has stabilized (no change greater 
than 1 percent of full scale for 30 sec), switch to monitor stack 
effluent and wait for a stable value. Record the time (upscale 
response time) required to reach 95 percent of the final stable 
value.
    6.3.2  Next, introduce a high-level calibration gas and repeat 
the above procedure. Repeat the entire procedure three times and 
determine the mean upscale and downscale response times. The longer 
of the two means is the system response time.
    6.4  Calibration Error Test Procedure.
    6.4.1  Sampling Strategy. Challenge the CEMS with zero gas and 
EPA Protocol 1 cylinder gases at measurement points within the 
ranges specified in section 4.7.
    6.4.1.1  The daily calibration gases, if Protocol 1, may be used 
for this test.

BILLING CODE 6560-50-P

[[Page 53035]]

[GRAPHIC] [TIFF OMITTED] TR30SE99.011



BILLING CODE 6560-50-C

[[Page 53036]]

    6.4.1.2  Operate the CEMS as nearly as possible in its normal 
sampling mode. The calibration gas should be injected into the 
sampling system as close to the sampling probe outlet as practical 
and must pass through all filters, scrubbers, conditioners, and 
other monitor components used during normal sampling. Challenge the 
CEMS three non-consecutive times at each measurement point and 
record the responses. The duration of each gas injection should be 
for a sufficient period of time to ensure that the CEMS surfaces are 
conditioned.
    6.4.2  Calculations. Summarize the results on a data sheet. An 
example data sheet is shown in Figure 2. Average the differences 
between the instrument response and the certified cylinder gas value 
for each gas. Calculate three CE results according to Equation 1. No 
confidence coefficient is used in CE calculations.

7. Equations

    Calibration Error. Calculate CE using Equation 1.
    [GRAPHIC] [TIFF OMITTED] TR30SE99.012
    
Where:

d= Mean difference between CEMS response and the known reference 
concentration, determined using Equation 2.
[GRAPHIC] [TIFF OMITTED] TR30SE99.013

Where:

di = Individual difference between CEMS response and the 
known reference concentration.

8. Reporting

    At a minimum, summarize in tabular form the results of the CD, 
response time, and CE test, as appropriate. Include all data sheets, 
calculations, CEMS data records, and cylinder gas or reference 
material certifications.

BILLING CODE 6560-50-P

[[Page 53037]]

[GRAPHIC] [TIFF OMITTED] TR30SE99.014



BILLING CODE 6560-50-C

[[Page 53038]]

9. References

    1. Measurement of Volatile Organic Compounds-Guideline Series. 
U.S. Environmental Protection Agency, Research Triangle Park, North 
Carolina, 27711, EPA-450/2-78-041, June 1978.
    2. Traceability Protocol for Establishing True Concentrations of 
Gases Used for Calibration and Audits of Continuous Source Emission 
Monitors (Protocol No. 1). U.S. Environmental Protection Agency ORD/
EMSL, Research Triangle Park, North Carolina, 27711, June 1978.
    3. Gasoline Vapor Emission Laboratory Evaluation-Part 2. U.S. 
Environmental Protection Agency, OAQPS, Research Triangle Park, 
North Carolina, 27711, EMB Report No. 76-GAS-6, August 1975.
* * * * *

PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS 
FOR SOURCE CATEGORIES

    1. The authority citation for part 63 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

    2. Part 63, subpart EEE, is revised to read as follows:

Subpart EEE--National Emission Standards for Hazardous Air 
Pollutants from Hazardous Waste Combustors

General

Sec.
63.1200  Who is subject to these regulations?
63.1201  Definitions and acronyms used in this subpart.
63.1202 [Reserved]

Emissions Standards and Operating Limits

63.1203  What are the standards for hazardous waste incinerators?
63.1204  What are the standards for hazardous waste burning cement 
kilns?
63.1205  What are the standards for hazardous waste burning 
lightweight aggregate kilns?

Monitoring and Compliance Provisions

63.1206  When and how must you comply with the standards and 
operating requirements?
63.1207  What are the performance testing requirements?
63.1208  What are the test methods?
63.1209  What are the monitoring requirements?

Notification, Reporting and Recordkeeping

63.1210  What are the notification requirements?
63.1211  What are the recordkeeping and reporting requirements?
63.1212  What are the other requirements pertaining to the NIC and 
associated progress reports?

Other

63.1213  How can the compliance date be extended to install 
pollution prevention or waste minimization controls?
Table 1 to Subpart EEE of Part 63--General Provisions Applicable to 
Subpart EEE
Appendix A to Subpart EEE--Quality Assurance Procedures for 
Continuous Emissions Monitors Used for Hazardous Waste Combustors

Subpart EEE--National Emission Standards for Hazardous Air 
Pollutants from Hazardous Waste Combustors General


Sec. 63.1200  Who is subject to these regulations?

    The provisions of this subpart apply to all hazardous waste 
combustors: hazardous waste incinerators, hazardous waste burning 
cement kilns, and hazardous waste burning lightweight aggregate kilns, 
except as provided in Table 1 of this section. Hazardous waste 
combustors are also subject to applicable requirements under parts 260-
270 of this chapter.
    (a) What if I am an area source? (1) Both area sources and major 
sources are subject to this subpart.
    (2) Both area sources and major sources, not previously subject to 
title V, are immediately subject to the requirement to apply for and 
obtain a title V permit in all States, and in areas covered by part 71 
of this chapter.
    (b) These regulations in this subpart do not apply to sources 
that meet the criteria in Table 1 of this Section, as follows:

   Table 1 to Sec.  63.1200.-- Hazardous Waste Combustors Exempt from
                               Subpart EEE
------------------------------------------------------------------------
               If                       And if               Then
------------------------------------------------------------------------
(1) You are a previously          (i) You ceased      You are no longer
 affected source.                  feeding hazardous   subject to this
                                   waste for a         subpart (Subpart
                                   period of time      EEE).
                                   greater than the
                                   hazardous waste
                                   residence time
                                   (i.e., hazardous
                                   waste no longer
                                   resides in the
                                   combustion
                                   chamber);.
                                  (ii) You are in
                                   compliance with
                                   the closure
                                   requirements of
                                   subpart G, parts
                                   264 or 265 of
                                   this chapter;.
                                  (iii) You begin
                                   complying with
                                   the requirements
                                   of all other
                                   applicable
                                   standards of this
                                   part (Part 63);
                                   and.
                                  (iv) You notify
                                   the Administrator
                                   in writing that
                                   you are no longer
                                   an affected
                                   source under this
                                   subpart (Subpart
                                   EEE).
(2) You are a research,           You operate for no  You are not
 development, and demonstration    longer than one     subject to this
 source.                           year after first    subpart (Subpart
                                   burning hazardous   EEE). This
                                   waste (Note that    exemption applies
                                   the Administrator   even if there is
                                   can extent this     a hazardous waste
                                   one-year            combustor at the
                                   restriction on a    plant site that
                                   case-by-case        is regulated
                                   basis upon your     under this
                                   written request     subpart. You
                                   documenting when    still, however,
                                   you first burned    remain subject to
                                   hazardous waste     Sec.  270.65 of
                                   and the             this chapter.
                                   justification for
                                   needing
                                   additional time
                                   to perform
                                   research,
                                   development, or
                                   demonstration
                                   operations.).
(3) The only hazardous wastes       ................  You are not
 you burn are exempt from                              subject to the
 regulation under Sec.                                 requirements of
 266.100(b) of this chapter.                           this subpart
                                                       (Subpart EEE).
------------------------------------------------------------------------


[[Page 53039]]

    (c) Table 1 of this section specifies the provisions of subpart A 
(General Provisions, Secs. 63.1-63.15) that apply and those that do not 
apply to sources affected by this subpart.


Sec. 63.1201  Definitions and acronyms used in this subpart.

    (a) The terms used in this subpart are defined in the Act, in 
subpart A of this part, or in this section as follows:
    Air pollution control system means the equipment used to reduce the 
release of particulate matter and other pollutants to the atmosphere.
    Automatic waste feed cutoff (AWFCO) system means a system comprised 
of cutoff valves, actuator, sensor, data manager, and other necessary 
components and electrical circuitry designed, operated and maintained 
to stop the flow of hazardous waste to the combustion unit 
automatically and immediately (except as provided by 
Sec. 63.1206(c)(2)(viii)) when any operating requirement is exceeded.
    By-pass duct means a device which diverts a minimum of 10 percent 
of a cement kiln's off gas, or a device which the Administrator 
determines on a case-by-case basis diverts a sample of kiln gas that 
contains levels of carbon monoxide or hydrocarbons representative of 
the levels in the kiln.
    Combustion chamber means the area in which controlled flame 
combustion of hazardous waste occurs.
    Continuous monitor means a device which continuously samples the 
regulated parameter specified in Sec. 63.1209 without interruption, 
evaluates the detector response at least once every 15 seconds, and 
computes and records the average value at least every 60 seconds, 
except during allowable periods of calibration and except as defined 
otherwise by the CEMS Performance Specifications in appendix B, part 60 
of this chapter.
    Dioxin/furan and dioxins and furans mean tetra-, penta-, hexa-, 
hepta-, and octa-chlorinated dibenzo dioxins and furans.
    Existing source means any affected source that is not a new source.
    Feedrate operating limits means limits on the feedrate of materials 
(e.g., metals, chlorine) to the combustor that are established based on 
comprehensive performance testing. The limits are established and 
monitored by knowing the concentration of the limited material (e.g., 
chlorine) in each feedstream and the flowrate of each feedstream.
    Feedstream means any material fed into a hazardous waste combustor, 
including, but not limited to, any pumpable or nonpumpable solid, 
liquid, or gas.
    Flowrate means the rate at which a feedstream is fed into a 
hazardous waste combustor.
    Hazardous waste is defined in Sec. 261.3 of this chapter.
    Hazardous waste burning cement kiln means a rotary kiln and any 
associated preheater or precalciner devices that produce clinker by 
heating limestone and other materials for subsequent production of 
cement for use in commerce, and that burns hazardous waste at any time.
    Hazardous waste combustor means a hazardous waste incinerator, 
hazardous waste burning cement kiln, or hazardous waste burning 
lightweight aggregate kiln.
    Hazardous waste incinerator means a device defined as an 
incinerator in Sec. 260.10 of this chapter and that burns hazardous 
waste at any time.
    Hazardous waste lightweight aggregate kiln means a rotary kiln that 
produces clinker by heating materials such as slate, shale and clay for 
subsequent production of lightweight aggregate used in commerce, and 
that burns hazardous waste at any time.
    Hazardous waste residence time means the time elapsed from cutoff 
of the flow of hazardous waste into the combustor (including, for 
example, the time required for liquids to flow from the cutoff valve 
into the combustor) until solid, liquid, and gaseous materials from the 
hazardous waste, excluding residues that may adhere to combustion 
chamber surfaces, exit the combustion chamber. For combustors with 
multiple firing systems whereby the residence time may vary for the 
firing systems, the hazardous waste residence time for purposes of 
complying with this subpart means the longest residence time for any 
firing system in use at the time of waste cutoff.
    Initial comprehensive performance test means the comprehensive 
performance test that is used as the basis for initially demonstrating 
compliance with the standards.
    In-line kiln raw mill means a hazardous waste burning cement kiln 
design whereby kiln gas is ducted through the raw material mill for 
portions of time to facilitate drying and heating of the raw material.
    Instantaneous monitoring means continuously sampling, detecting, 
and recording the regulated parameter without use of an averaging 
period.
    Monovent means an exhaust configuration of a building or emission 
control device (e.g. positive pressure fabric filter) that extends the 
length of the structure and has a width very small in relation to its 
length (i.e., length to width ratio is typically greater than 5:1). The 
exhaust may be an open vent with or without a roof, louvered vents, or 
a combination of such features.
    MTEC means maximum theoretical emissions concentration of metals or 
HCl/Cl, expressed as g/dscm, and is calculated by dividing the 
feedrate by the gas flowrate.
    New source means any affected source the construction or 
reconstruction of which is commenced after April 19, 1996.
    One-minute average means the average of detector responses 
calculated at least every 60 seconds from responses obtained at least 
every 15 seconds.
    Operating record means a documentation retained at the facility for 
ready inspection by authorized officials of all information required by 
the standards to document and maintain compliance with the applicable 
regulations, including data and information, reports, notifications, 
and communications with regulatory officials.
    Operating requirements means operating terms or conditions, limits, 
or operating parameter limits developed under this subpart that ensure 
compliance with the emission standards.
    Raw material feed means the prepared and mixed materials, which 
include but are not limited to materials such as limestone, clay, 
shale, sand, iron ore, mill scale, cement kiln dust and flyash, that 
are fed to a cement or lightweight aggregate kiln. Raw material feed 
does not include the fuels used in the kiln to produce heat to form the 
clinker product.
    Research, development, and demonstration source means a source 
engaged in laboratory, pilot plant, or prototype demonstration 
operations:
    (1) Whose primary purpose is to conduct research, development, or 
short-term demonstration of an innovative and experimental hazardous 
waste treatment technology or process; and
    (2) Where the operations are under the close supervision of 
technically-trained personnel.
    Rolling average means the average of all one-minute averages over 
the averaging period.
    Run means the net period of time during which an air emission 
sample is collected under a given set of operating conditions. Three or 
more runs constitutes a test. Unless otherwise specified, a run may be 
either intermittent or continuous.
    Run average means the average of the one-minute average parameter 
values for a run.
    TEQ means toxicity equivalence, the international method of 
relating the toxicity of various dioxin/furan congeners to the toxicity 
of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

[[Page 53040]]

    You means the owner or operator of a hazardous waste combustor.
    (b) The acronyms used in this subpart refer to the following:
    AWFCO means automatic waste feed cutoff.
    CAS means chemical abstract services registry.
    CEMS means continuous emissions monitoring system.
    CMS means continuous monitoring system.
    DRE means destruction and removal efficiency.
    MACT means maximum achievable control technology.
    MTEC means maximum theoretical emissions concentration.
    NIC means notification of intent to comply.


Sec. 63.1202  [Reserved]

Emissions Standards and Operating Limits


Sec. 63.1203  What are the standards for hazardous waste incinerators?

    (a) Emission limits for existing sources You must not discharge or 
cause combustion gasses to be emitted into the atmosphere that contain:
    (1) For dioxins and furans:
    (i) Emissions in excess of 0.20 ng TEQ/dscm corrected to 7 percent 
oxygen; or
    (ii) Emissions in excess of 0.40 ng TEQ/dscm corrected to 7 percent 
oxygen provided that the combustion gas temperature at the inlet to the 
initial particulate matter control device is 400 deg.F or lower based 
on the average of the test run average temperatures; \1\
---------------------------------------------------------------------------

    \1\ For purposes of compliance, operation of a wet particulate 
control device is presumed to meet the 400 deg.F or lower 
requirement.
---------------------------------------------------------------------------

    (2) Mercury in excess of 130 g/dscm corrected to 7 percent 
oxygen;
    (3) Lead and cadmium in excess of 240 ``g/dscm, combined emissions, 
corrected to 7 percent oxygen;
    (4) Arsenic, beryllium, and chromium in excess of 97 ``g/dscm, 
combined emissions, corrected to 7 percent oxygen;
    (5) For carbon monoxide and hydrocarbons, either:
    (i) Carbon monoxide in excess of 100 parts per million by volume, 
over an hourly rolling average (monitored continuously with a 
continuous emissions monitoring system), dry basis and corrected to 7 
percent oxygen, and hydrocarbons in excess of 10 parts per million by 
volume over an hourly rolling average (monitored continuously with a 
continuous emissions monitoring system), dry basis, corrected to 7 
percent oxygen, and reported as propane, at any time during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec. 63.1206(b)(7); or
    (ii) Hydrocarbons in excess of 10 parts per million by volume, over 
an hourly rolling average (monitored continuously with a continuous 
emissions monitoring system), dry basis, corrected to 7 percent oxygen, 
and reported as propane;
    (6) Hydrochloric acid and chlorine gas in excess of 77 parts per 
million by volume, combined emissions, expressed as hydrochloric acid 
equivalents, dry basis and corrected to 7 percent oxygen; and
    (7) Particulate matter in excess of 34 mg/dscm corrected to 7 
percent oxygen.
    (b) Emission limits for new sources. You must not discharge or 
cause combustion gases to be emitted into the atmosphere that contain:
    (1) Dioxins and furans in excess of 0.20 ng TEQ/dscm, corrected to 
7 percent oxygen;
    (2) Mercury in excess of 45 g/dscm corrected to 7 percent 
oxygen;
    (3) Lead and cadmium in excess of 24 g/dscm, combined 
emissions, corrected to 7 percent oxygen;
    (4) Arsenic, beryllium, and chromium in excess of 97 g/
dscm, combined emissions, corrected to 7 percent oxygen;
    (5) For carbon monoxide and hydrocarbons, either:
    (i) Carbon monoxide in excess of 100 parts per million by volume, 
over an hourly rolling average (monitored continuously with a 
continuous emissions monitoring system), dry basis and corrected to 7 
percent oxygen, and hydrocarbons in excess of 10 parts per million by 
volume over an hourly rolling average (monitored continuously with a 
continuous emissions monitoring system), dry basis, corrected to 7 
percent oxygen, and reported as propane, at any time during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec. 63.1206(b)(7); or
    (ii) Hydrocarbons in excess of 10 parts per million by volume, over 
an hourly rolling average (monitored continuously with a continuous 
emissions monitoring system), dry basis, corrected to 7 percent oxygen, 
and reported as propane;
    (6) Hydrochloric acid and chlorine gas in excess of 21 parts per 
million by volume, combined emissions, expressed as hydrochloric acid 
equivalents, dry basis and corrected to 7 percent oxygen; and
    (7) Particulate matter in excess of 34 mg/dscm corrected to 7 
percent oxygen.
    (c) Destruction and removal efficiency (DRE) standard. (1) 99.99% 
DRE. Except as provided in paragraph (c)(2) of this section, you must 
achieve a destruction and removal efficiency (DRE) of 99.99% for each 
principle organic hazardous constituent (POHC) designated under 
paragraph (c)(3) of this section. You must calculate DRE for each POHC 
from the following equation:
[GRAPHIC] [TIFF OMITTED] TR30SE99.015

Where:

Win=mass feedrate of one principal organic hazardous 
constituent (POHC) in a waste feedstream; and
Wout=mass emission rate of the same POHC present in exhaust 
emissions prior to release to the atmosphere
    (2) 99.9999% DRE. If you burn the dioxin-listed hazardous wastes 
FO20, FO21, FO22, FO23, FO26, or FO27 (see Sec. 261.31 of this 
chapter), you must achieve a destruction and removal efficiency (DRE) 
of 99.9999% for each principle organic hazardous constituent (POHC) 
that you designate under paragraph (c)(3) of this section. You must 
demonstrate this DRE performance on POHCs that are more difficult to 
incinerate than tetro-, penta-, and hexachlorodibenzo-p-dioxins and 
dibenzofurans. You must use the equation in paragraph (c)(1) of this 
section calculate DRE for each POHC. In addition, you must notify the 
Administrator of your intent to incinerate hazardous wastes FO20, FO21, 
FO22, FO23, FO26, or FO27.
    (3) Principal organic hazardous constituents (POHCs). (i) You must 
treat the Principal Organic Hazardous Constituents (POHCs) in the waste 
feed that you specify under paragraph (c)(3)(ii) of this section to the 
extent required by paragraphs (c)(1) and (c)(2) of this section.
    (ii) You must specify one or more POHCs from the list of hazardous 
air pollutants established by 42 U.S.C. 7412(b)(1), excluding 
caprolactam (CAS number 105602) as provided by Sec. 63.60, for each 
waste to be burned. You must base this specification on the degree of 
difficulty of incineration of the organic constituents in the waste and 
on their concentration or mass in the waste feed, considering the 
results of waste analyses or other data and information.
    (d) Significant figures. The emission limits provided by paragraphs 
(a) and (b) of this section are presented with two significant figures. 
Although you must perform intermediate calculations using at least 
three significant figures, you may round the resultant emission levels 
to two significant figures to document compliance.

[[Page 53041]]

    (e) Air emission standards for equipment leaks, tanks, surface 
impoundments, and containers. You are subject to the air emission 
standards of subparts BB and CC, part 264, of this chapter.


Sec. 63.1204  What are the standards for hazardous waste burning cement 
kilns?

    (a) Emission limits for existing sources. You must not discharge or 
cause combustion gases to be emitted into the atmosphere that contain:
    (1) For dioxins and furans:
    (i) Emissions in excess of 0.20 ng TEQ/dscm corrected to 7 percent 
oxygen; or
    (ii) Emissions in excess of 0.40 ng TEQ/dscm corrected to 7 percent 
oxygen provided that the combustion gas temperature at the inlet to the 
initial dry particulate matter control device is 400 deg.F or lower 
based on the average of the test run average temperatures;
    (2) Mercury in excess of 120 g/dscm corrected to 7 percent 
oxygen;
    (3) Lead and cadmium in excess of 240 g/dscm, combined 
emissions, corrected to 7 percent oxygen;
    (4) Arsenic, beryllium, and chromium in excess of 56 g/
dscm, combined emissions, corrected to 7 percent oxygen;
    (5) Carbon monoxide and hydrocarbons. (i) For kilns equipped with a 
by-pass duct or midkiln gas sampling system, either:
    (A) Carbon monoxide in the by-pass duct or midkiln gas sampling 
system in excess of 100 parts per million by volume, over an hourly 
rolling average (monitored continuously with a continuous emissions 
monitoring system), dry basis and corrected to 7 percent oxygen, and 
hydrocarbons in the by-pass duct in excess of 10 parts per million by 
volume over an hourly rolling average (monitored continuously with a 
continuous emissions monitoring system), dry basis, corrected to 7 
percent oxygen, and reported as propane, at any time during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec. 63.1206(b)(7); or
    (B) Hydrocarbons in the by-pass duct or midkiln gas sampling system 
in excess of 10 parts per million by volume, over an hourly rolling 
average (monitored continuously with a continuous emissions monitoring 
system), dry basis, corrected to 7 percent oxygen, and reported as 
propane;
    (ii) For kilns not equipped with a by-pass duct or midkiln gas 
sampling system, either:
    (A) Hydrocarbons in the main stack in excess of 20 parts per 
million by volume, over an hourly rolling average (monitored 
continuously with a continuous emissions monitoring system), dry basis, 
corrected to 7 percent oxygen, and reported as propane; or
    (B) Carbon monoxide in the main stack in excess of 100 parts per 
million by volume, over an hourly rolling average (monitored 
continuously with a continuous emissions monitoring system), dry basis 
and corrected to 7 percent oxygen, and hydrocarbons in the main stack 
in excess of 20 parts per million by volume over an hourly rolling 
average (monitored continuously with a continuous emissions monitoring 
system), dry basis, corrected to 7 percent oxygen, and reported as 
propane, at any time during the destruction and removal efficiency 
(DRE) test runs or their equivalent as provided by Sec. 63.1206(b)(7).
    (6) Hydrochloric acid and chlorine gas in excess of 130 parts per 
million by volume, combined emissions, expressed as hydrochloric acid 
equivalents, dry basis, corrected to 7 percent oxygen; and
    (7) Particulate matter in excess of 0.15 kg/Mg dry feed and opacity 
greater than 20 percent.
    (i) You must use suitable methods to determine the kiln raw 
material feedrate.
    (ii) Except as provided in paragraph (a)(7)(iii) of this section, 
you must compute the particulate matter emission rate, E, from the 
following equation:
[GRAPHIC] [TIFF OMITTED] TR30SE99.016

where:

E = emission rate of particulate matter, kg/Mg of kiln raw material 
feed;
Cs = concentration of particulate matter, kg/dscm;
Qsd = volumetric flowrate of effluent gas, dscm/hr;
P = total kiln raw material feed (dry basis), Mg/hr.

    (iii) If you operate a preheater or preheater/precalciner kiln with 
dual stacks, you must test simultaneously and compute the combined 
particulate matter emission rate, Ec, from the following 
equation:
[GRAPHIC] [TIFF OMITTED] TR30SE99.017

where:

Ec = the combined emission rate of particulate matter from 
the kiln and bypass stack, kg/Mg of kiln raw material feed;
Csk = concentration of particulate matter in the kiln 
effluent, kg/dscm;
Qsdk = volumetric flowrate of kiln effluent gas, dscm/hr;
Csb = concentration of particulate matter in the bypass 
stack effluent, kg/dscm;
Qsdb = volumetric flowrate of bypass stack effluent gas, 
dscm/hr;
P = total kiln raw material feed (dry basis), Mg/hr.

    (b) Emission limits for new sources. You must not discharge or 
cause combustion gases to be emitted into the atmosphere that contain:
    (1) For dioxins and furans:
    (i) Emissions in excess of 0.20 ng TEQ/dscm corrected to 7 percent 
oxygen; or
    (ii) Emissions in excess of 0.40 ng TEQ/dscm corrected to 7 percent 
oxygen provided that the combustion gas temperature at the inlet to the 
initial dry particulate matter control device is 400  deg.F or lower 
based on the average of the test run average temperatures;
    (2) Mercury in excess of 56 g/dscm corrected to 7 percent 
oxygen;
    (3) Lead and cadmium in excess of 180 g/dscm, combined 
emissions, corrected to 7 percent oxygen;
    (4) Arsenic, beryllium, and chromium in excess of 54 g/
dscm, combined emissions, corrected to 7 percent oxygen;
    (5) Carbon monoxide and hydrocarbons. (i) For kilns equipped with a 
by-pass duct or midkiln gas sampling system, carbon monoxide and 
hydrocarbons emissions are limited in both the bypass duct or midkiln 
gas sampling system and the main stack as follows:
    (A) Emissions in the by-pass or midkiln gas sampling system are 
limited to either:
    (1) Carbon monoxide in excess of 100 parts per million by volume, 
over an hourly rolling average (monitored continuously with a 
continuous emissions monitoring system), dry basis and corrected to 7 
percent oxygen, and hydrocarbons in excess of 10 parts per million by 
volume over an hourly rolling average (monitored continuously with a 
continuous emissions monitoring system), dry basis, corrected to 7 
percent oxygen, and reported as propane, at any time during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec. 63.1206(b)(7); or
    (2) Hydrocarbons in the by-pass duct or midkiln gas sampling system 
in excess of 10 parts per million by volume, over an hourly rolling 
average (monitored continuously with a continuous emissions monitoring 
system), dry basis, corrected to 7 percent oxygen, and reported as 
propane; and
    (B) Hydrocarbons in the main stack are limited, if construction of 
the kiln

[[Page 53042]]

commenced after April 19, 1996 at a plant site where a cement kiln 
(whether burning hazardous waste or not) did not previously exist, to 
50 parts per million by volume, over a 30-day block average (monitored 
continuously with a continuous monitoring system), dry basis, corrected 
to 7 percent oxygen, and reported as propane.
    (ii) For kilns not equipped with a by-pass duct or midkiln gas 
sampling system, hydrocarbons and carbon monoxide are limited in the 
main stack to either:
    (A) Hydrocarbons not exceeding 20 parts per million by volume, over 
an hourly rolling average (monitored continuously with a continuous 
emissions monitoring system), dry basis, corrected to 7 percent oxygen, 
and reported as propane; or
    (B) (1) Carbon monoxide not exceeding 100 part per million by 
volume, over an hourly rolling average (monitored continuously with a 
continuous emissions monitoring system), dry basis, corrected to 7 
percent oxygen; and
    (2) Hydrocarbons not exceeding 20 parts per million by volume, over 
an hourly rolling average (monitored continuously with a continuous 
monitoring system), dry basis, corrected to 7 percent oxygen, and 
reported as propane at any time during the destruction and removal 
efficiency (DRE) test runs or their equivalent as provided by 
Sec. 63.1206(b)(7); and
    (3) If construction of the kiln commenced after April 19, 1996 at a 
plant site where a cement kiln (whether burning hazardous waste or not) 
did not previously exist, hydrocarbons are limited to 50 parts per 
million by volume, over a 30-day block average (monitored continuously 
with a continuous monitoring system), dry basis, corrected to 7 percent 
oxygen, and reported as propane.
    (6) Hydrochloric acid and chlorine gas in excess of 86 parts per 
million, combined emissions, expressed as hydrochloric acid 
equivalents, dry basis and corrected to 7 percent oxygen; and
    (7) Particulate matter in excess of 0.15 kg/Mg dry feed and opacity 
greater than 20 percent.
    (i) You must use suitable methods to determine the kiln raw 
material feedrate.
    (ii) Except as provided in paragraph (a)(7)(iii) of this section, 
you must compute the particulate matter emission rate, E, from the 
equation specified in paragraph (a)(7)(ii) of this section.
    (iii) If you operate a preheater or preheater/precalciner kiln with 
dual stacks, you must test simultaneously and compute the combined 
particulate matter emission rate, Ec, from the equation specified in 
paragraph (a)(7)(iii) of this section.
    (c) Destruction and removal efficiency (DRE) standard--(1) 99.99% 
DRE. Except as provided in paragraph (c)(2) of this section, you must 
achieve a destruction and removal efficiency (DRE) of 99.99% for each 
principle organic hazardous constituent (POHC) designated under 
paragraph (c)(3) of this section. You must calculate DRE for each POHC 
from the following equation:
[GRAPHIC] [TIFF OMITTED] TR30SE99.018

Where:

Win=mass feedrate of one principal organic hazardous 
constituent (POHC) in a waste feedstream; and
Wout=mass emission rate of the same POHC present in exhaust 
emissions prior to release to the atmosphere

    (2) 99.9999% DRE. If you burn the dioxin-listed hazardous wastes 
FO20, FO21, FO22, FO23, FO26, or FO27 (see Sec. 261.31 of this 
chapter), you must achieve a destruction and removal efficiency (DRE) 
of 99.9999% for each principle organic hazardous constituent (POHC) 
that you designate under paragraph (c)(3) of this section. You must 
demonstrate this DRE performance on POHCs that are more difficult to 
incinerate than tetro-, penta-, and hexachlorodibenzo-p-dioxins and 
dibenzofurans. You must use the equation in paragraph (c)(1) of this 
section calculate DRE for each POHC. In addition, you must notify the 
Administrator of your intent to burn hazardous wastes FO20, FO21, FO22, 
FO23, FO26, or FO27.
    (3) Principal organic hazardous constituents (POHCs). (i) You must 
treat the Principal Organic Hazardous Constituents (POHCs) in the waste 
feed that you specify under paragraph (c)(3)(ii) of this section to the 
extent required by paragraphs (c)(1) and (c)(2) of this section.
    (ii) You must specify one or more POHCs from the list of hazardous 
air pollutants established by 42 U.S.C. 7412(b)(1), excluding 
caprolactam (CAS number 105602) as provided by Sec. 63.60, for each 
waste to be burned. You must base this specification on the degree of 
difficulty of incineration of the organic constituents in the waste and 
on their concentration or mass in the waste feed, considering the 
results of waste analyses or other data and information.
    (d) Cement kilns with in-line kiln raw mills--(1) General. (i) You 
must conduct performance testing when the raw mill is on-line and when 
the mill is off-line to demonstrate compliance with the emission 
standards, and you must establish separate operating parameter limits 
under Sec. 63.1209 for each mode of operation, except as provided by 
paragraph (d)(1)(iv) of this section.
    (ii) You must document in the operating record each time you change 
from one mode of operation to the alternate mode and begin complying 
with the operating parameter limits for that alternate mode of 
operation.
    (iii) You must establish rolling averages for the operating 
parameter limits anew (i.e., without considering previous recordings) 
when you begin complying with the operating limits for the alternate 
mode of operation.
    (iv) If your in-line kiln raw mill has dual stacks, you may assume 
that the dioxin/furan emission levels in the by-pass stack and the 
operating parameter limits determined during performance testing of the 
by-pass stack when the raw mill is off-line are the same as when the 
mill is on-line.
    (2) Emissions averaging. You may comply with the mercury, 
semivolatile metal, low volatile metal, and hydrochloric acid/chlorine 
gas emission standards on a time-weighted average basis under the 
following procedures:
    (i) Averaging methodology. You must calculate the time-weighted 
average emission concentration with the following equation:
Where:

Ctotal=time-weighted average concentration of a regulated 
constituent considering both raw mill on time and off time.
Cmill-off=average performance test concentration of 
regulated constituent with the raw mill off-line.
Cmill-on=average performance test concentration of regulated 
constituent with the raw mill on-line.
Tmill-off=time when kiln gases are not routed through the 
raw mill
Tmill-on=time when kiln gases are routed through the raw 
mill 
[GRAPHIC] [TIFF OMITTED] TR30SE99.019


[[Page 53043]]


    (ii) Compliance. (A) If you use this emission averaging provision, 
you must document in the operating record compliance with the emission 
standards on an annual basis by using the equation provided by 
paragraph (d)(2) of this section.
    (B) Compliance is based on one-year block averages beginning on the 
day you submit the initial notification of compliance.
    (iii) Notification. (A) If you elect to document compliance with 
one or more emission standards using this emission averaging provision, 
you must notify the Administrator in the initial comprehensive 
performance test plan submitted under Sec. 63.1207(e).
    (B) You must include historical raw mill operation data in the 
performance test plan to estimate future raw mill down-time and 
document in the performance test plan that estimated emissions and 
estimated raw mill down-time will not result in an exceedance of an 
emission standard on an annual basis.
    (C) You must document in the notification of compliance submitted 
under Sec. 63.1207(j) that an emission standard will not be exceeded 
based on the documented emissions from the performance test and 
predicted raw mill down-time.
    (e) Preheater or preheater/precalciner kilns with dual stacks.--(1) 
General. You must conduct performance testing on each stack to 
demonstrate compliance with the emission standards, and you must 
establish operating parameter limits under Sec. 63.1209 for each stack, 
except as provided by paragraph (d)(1)(iv) of this section for dioxin/
furan emissions testing and operating parameter limits for the by-pass 
stack of in-line raw mills.
    (2) Emissions averaging. You may comply with the mercury, 
semivolatile metal, low volatile metal, and hydrochloric acid/chlorine 
gas emission standards specified in this section on a gas flowrate-
weighted average basis under the following procedures:
    (i) Averaging methodology. You must calculate the gas flowrate-
weighted average emission concentration using the following equation: 
[GRAPHIC] [TIFF OMITTED] TR30SE99.020

Where

Ctot=gas flowrate-weighted average concentration of the 
regulated constituent
Cmain=average performance test concentration demonstrated in 
the main stack
Cbypass=average performance test concentration demonstrated 
in the bypass stack
Qmain=volumetric flowrate of main stack effluent gas
Qbypass=volumetric flowrate of bypass effluent gas

    (ii) Compliance. (A) You must demonstrate compliance with the 
emission standard(s) using the emission concentrations determined from 
the performance tests and the equation provided by paragraph (e)(1) of 
this section; and
    (B) You must develop operating parameter limits for bypass stack 
and main stack flowrates that ensure the emission concentrations 
calculated with the equation in paragraph (e)(1) of this section do not 
exceed the emission standards on a 12-hour rolling average basis. You 
must include these flowrate limits in the Notification of Compliance.
    (iii) Notification. If you elect to document compliance under this 
emissions averaging provision, you must:
    (A) Notify the Administrator in the initial comprehensive 
performance test plan submitted under Sec. 63.1207(e). The performance 
test plan must include, at a minimum, information describing the 
flowrate limits established under paragraph (e)(2)(ii)(B) of this 
section; and
    (B) Document in the Notification of Compliance submitted under 
Sec. 63.1207(j) the demonstrated gas flowrate-weighted average 
emissions that you calculate with the equation provided by paragraph 
(e)(2) of this section.
    (f) Significant figures. The emission limits provided by paragraphs 
(a) and (b) of this section are presented with two significant figures. 
Although you must perform intermediate calculations using at least 
three significant figures, you may round the resultant emission levels 
to two significant figures to document compliance.
    (g) Air emission standards for equipment leaks, tanks, surface 
impoundments, and containers. You are subject to the air emission 
standards of subparts BB and CC, part 264, of this chapter.
    (h) When you comply with the particulate matter requirements of 
paragraphs (a)(7) or (b)(7) of this section, you are exempt from the 
New Source Performance Standard for particulate matter and opacity 
under Sec. 60.60 of this chapter.


Sec. 63.1205  What are the standards for hazardous waste burning 
lightweight aggregate kilns?

    (a)  Emission limits for existing sources. You must not discharge 
or cause combustion gases to be emitted into the atmosphere that 
contain:
    (1) For dioxins and furans:
    (i) Emissions in excess of 0.20 ng TEQ/dscm corrected to 7 percent 
oxygen; or
    (ii) Emissions in excess of 0.40 ng TEQ/dscm corrected to 7 percent 
oxygen provided that the combustion gas temperature at the exit of the 
(last) combustion chamber (or exit of any waste heat recovery system) 
is rapidly quenched to 400 deg.F or lower based on the average of the 
test run average temperatures;
    (2) Mercury in excess of 47 g/dscm corrected to 7 percent 
oxygen;
    (3) Lead and cadmium in excess of 250 g/dscm, combined 
emissions, corrected to 7 percent oxygen;
    (4) Arsenic, beryllium, and chromium in excess of 110 g/
dscm, combined emissions, corrected to 7 percent oxygen;
    (5) Carbon monoxide and hydrocarbons. (i) Carbon monoxide in excess 
of 100 parts per million by volume, over an hourly rolling average 
(monitored continuously with a continuous emissions monitoring system), 
dry basis and corrected to 7 percent oxygen, and hydrocarbons in excess 
of 20 parts per million by volume over an hourly rolling average 
(monitored continuously with a continuous emissions monitoring system), 
dry basis, corrected to 7 percent oxygen, and reported as propane, at 
any time during the destruction and removal efficiency (DRE) test runs 
or their equivalent as provided by Sec. 63.1206(b)(7); or
    (ii) Hydrocarbons in excess of 20 parts per million by volume, over 
an hourly rolling average, dry basis, corrected to 7 percent oxygen, 
and reported as propane;
    (6) Hydrochloric acid and chlorine gas in excess of 230 parts per 
million by volume, combined emissions, expressed as hydrochloric acid 
equivalents, dry

[[Page 53044]]

basis and corrected to 7 percent oxygen; and
    (7) Particulate matter in excess of 57 mg/dscm corrected to 7 
percent oxygen.
    (b) Emission limits for new sources. You must not discharge or 
cause combustion gases to be emitted into the atmosphere that contain:
    (1) For dioxins and furans:
    (i) Emissions in excess of 0.20 ng TEQ/dscm corrected to 7 percent 
oxygen; or
    (ii) Emissions in excess of 0.40 ng TEQ/dscm corrected to 7 percent 
oxygen provided that the temperature at the exit of the (last) 
combustion chamber (or exit of any waste heat recovery system) is 
rapidly quenched to 400 deg.F or lower based on the average of the test 
run average temperatures;
    (2) Mercury in excess of 33 g/dscm corrected to 7 percent 
oxygen;
    (3) Lead and cadmium in excess of 43 g/dscm, combined 
emissions, corrected to 7 percent oxygen;
    (4) Arsenic, beryllium, and chromium in excess of 110 g/
dscm, combined emissions, corrected to 7 percent oxygen;
    (5) Carbon monoxide in excess of 100 parts per million by volume, 
over an hourly rolling average (monitored continuously with a 
continuous emissions monitoring system), dry basis and corrected to 7 
percent oxygen, and hydrocarbons in excess of 20 parts per million by 
volume over an hourly rolling average (monitored continuously with a 
continuous emissions monitoring system), dry basis, corrected to 7 
percent oxygen, and reported as propane, at any time during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec. 63.1206(b)(7); or
    (ii) Hydrocarbons in excess of 20 parts per million by volume, over 
an hourly rolling average, dry basis, corrected to 7 percent oxygen, 
and reported as propane;
    (6) Hydrochloric acid and chlorine gas in excess of 41 parts per 
million by volume, combined emissions, expressed as hydrochloric acid 
equivalents, dry basis and corrected to 7 percent oxygen; and
    (7) Particulate matter in excess of 57 mg/dscm corrected to 7 
percent oxygen.
    (c) Destruction and removal efficiency (DRE) standard--(1) 99.99% 
DRE. Except as provided in paragraph (c)(2) of this section, you must 
achieve a destruction and removal efficiency (DRE) of 99.99% for each 
principal organic hazardous constituent (POHC) designated under 
paragraph (c)(3) of this section. You must calculate DRE for each POHC 
from the following equation: 
[GRAPHIC] [TIFF OMITTED] TR30SE99.021

Where:

Win=mass feedrate of one principal organic hazardous 
constituent (POHC) in a waste feedstream; and
Wout=mass emission rate of the same POHC present in exhaust 
emissions prior to release to the atmosphere

    (2) 99.9999% DRE. If you burn the dioxin-listed hazardous wastes 
FO20, FO21, FO22, FO23, FO26, or FO27 (see Sec. 261.31 of this 
chapter), you must achieve a destruction and removal efficiency (DRE) 
of 99.9999% for each principal organic hazardous constituent (POHC) 
that you designate under paragraph (c)(3) of this section. You must 
demonstrate this DRE performance on POHCs that are more difficult to 
incinerate than tetro-, penta-, and hexachlorodibenzo-dioxins and 
dibenzofurans. You must use the equation in paragraph (c)(1) of this 
section calculate DRE for each POHC. In addition, you must notify the 
Administrator of your intent to burn hazardous wastes FO20, FO21, FO22, 
FO23, FO26, or FO27.
    (3) Principal organic hazardous constituents (POHCs). (i) You must 
treat the Principal Organic Hazardous Constituents (POHCs) in the waste 
feed that you specify under paragraph (c)(3)(ii) of this section to the 
extent required by paragraphs (c)(1) and (c)(2) of this section.
    (ii) You must specify one or more POHCs from the list of hazardous 
air pollutants established by 42 U.S.C. 7412(b)(1), excluding 
caprolactam (CAS number 105602) as provided by Sec. 63.60, for each 
waste to be burned. You must base this specification on the degree of 
difficulty of incineration of the organic constituents in the waste and 
on their concentration or mass in the waste feed, considering the 
results of waste analyses or other data and information.
    (d) Significant figures. The emission limits provided by paragraphs 
(a) and (b) of this section are presented with two significant figures. 
Although you must perform intermediate calculations using at least 
three significant figures, you may round the resultant emission levels 
to two significant figures to document compliance.
    (e) Air emission standards for equipment leaks, tanks, surface 
impoundments, and containers. You are subject to the air emission 
standards of subparts BB and CC, part 264, of this chapter.

Monitoring and Compliance Provisions


Sec. 63.1206  When and how must you comply with the standards and 
operating requirements?

    (a) Compliance dates-- (1) Compliance date for existing sources. 
You must comply with the standards of this subpart no later than 
September 30, 2002 unless the Administrator grants you an extension of 
time under Sec. 63.6(i) or Sec. 63.1213, or you comply with the 
requirements of paragraph (a)(2) of this section for sources that do 
not intend to comply with the emission standards.
    (2) Sources that do not intend to comply. Except for those sources 
meeting the requirements of Sec. 63.1210(b)(1)(iv), sources:
    (i) That signify in their Notification of Intent to Comply (NIC) an 
intent not to comply with the requirements of this subpart, must stop 
burning hazardous waste on or before October 1, 2001.
    (ii) That do not intend to comply with this subpart must include in 
their NIC a schedule that includes key dates for the steps to be taken 
to stop burning hazardous waste. Key dates include the date for 
submittal of RCRA closure documents required under subpart G, part 264, 
of this chapter.
    (3) New or reconstructed sources. (i) If you commenced construction 
or reconstruction of your hazardous waste combustor after April 19, 
1996, you must comply with this subpart by the later of September 30, 
1999 or the date the source starts operations, except as provided by 
paragraph (a)(3)(ii) of this section.
    (ii) For a standard in this subpart that is more stringent than the 
standard proposed on April 19, 1996, you may achieve compliance no 
later than September 30, 2002 if you comply with the standard proposed 
on April 19, 1996 after September 30, 1999. This exception does not 
apply, however, to new or reconstructed area source hazardous waste 
combustors that become major sources after September 30, 1999. As 
provided by Sec. 63.6(b)(7), such sources must comply with this subpart 
at startup.
    (b) Compliance with standards--(1) Applicability. The emission 
standards

[[Page 53045]]

and operating requirements set forth in this subpart apply at all times 
except:
    (i) During startup, shutdown, and malfunction, provided that 
hazardous waste is not in the combustion chamber (i.e., the hazardous 
waste feed to the combustor has been cutoff for a period of time not 
less than the hazardous waste residence time) during those periods of 
operation, as provided by paragraph (c)(2)(ii) of this section; and
    (ii) When hazardous waste is not in the combustion chamber (i.e., 
the hazardous waste feed to the combustor has been cutoff for a period 
of time not less than the hazardous waste residence time), and you 
have:
    (A) Submitted a written, one-time notice to the Administrator 
documenting compliance with all applicable requirements and standards 
promulgated under authority of the Clean Air Act, including sections 
112 and 129; and
    (B) Documented in the operating record that you are complying with 
such applicable requirements in lieu of the emission standards and 
operating requirements of this subpart.
    (2) Methods for determining compliance. The Administrator will 
determine compliance with the emission standards of this subpart as 
provided by Sec. 63.6(f)(2). Conducting performance testing under 
operating conditions representative of the extreme range of normal 
conditions is consistent with the requirements of 
Secs. 63.6(f)(2)(iii)(B) and 63.7(e)(1) to conduct performance testing 
under representative operating conditions.
    (3) Finding of compliance. The Administrator will make a finding 
concerning compliance with the emission standards and other 
requirements of this subpart as provided by Sec. 63.6(f)(3).
    (4) Extension of compliance with emission standards. The 
Administrator may grant an extension of compliance with the emission 
standards of this subpart as provided by Secs. 63.6(i) and 63.1213.
    (5) Changes in design, operation, or maintenance--(i) Changes that 
may adversely affect compliance. If you plan to change (as defined in 
paragraph (b)(6)(iii) of this section) the design, operation, or 
maintenance practices of the source in a manner that may adversely 
affect compliance with any emission standard that is not monitored with 
a CEMS:
    (A) Notification. You must notify the Administrator at least 60 
days prior to the change, unless you document circumstances that 
dictate that such prior notice is not reasonably feasible. The 
notification must include:
    (1) A description of the changes and which emission standards may 
be affected; and
    (2) A comprehensive performance test schedule and test plan under 
the requirements of Sec. 63.1207(f) that will document compliance with 
the affected emission standard(s);
    (B) Performance test. You must conduct a comprehensive performance 
test under the requirements of Secs. 63.1207(f)(1) and (g)(1) to 
document compliance with the affected emission standard(s) and 
establish operating parameter limits as required under Sec. 63.1209, 
and submit to the Administrator a Notification of Compliance under 
Secs. 63.1207(j) and 63.1210(d); and
    (C) Restriction on waste burning. (1) Except as provided by 
paragraph (b)(5)(i)(C)(2) of this section, after the change and prior 
to submitting the notification of compliance, you must not burn 
hazardous waste for more than a total of 720 hours and only for 
purposes of pretesting or comprehensive performance testing.
    (2) You may petition the Administrator to obtain written approval 
to burn hazardous waste in the interim prior to submitting a 
Notification of Compliance for purposes other than testing or 
pretesting. You must specify operating requirements, including limits 
on operating parameters, that you determine will ensure compliance with 
the emission standards of this subpart based on available information. 
The Administrator will review, modify as necessary, and approve if 
warranted the interim operating requirements.
    (ii) Changes that will not affect compliance. If you determine that 
a change will not adversely affect compliance with the emission 
standards or operating requirements, you must document the change in 
the operating record upon making such change. You must revise as 
necessary the performance test plan, Documentation of Compliance, 
Notification of Compliance, and start-up, shutdown, and malfunction 
plan to reflect these changes.
    (iii) Definition of ``change''. For purposes of paragraph (b)(6) of 
this section, ``change'' means any change in design, operation, or 
maintenance practices that were documented in the comprehensive 
performance test plan, Notification of Compliance, or startup, 
shutdown, and malfunction plan.
    (6) Compliance with the carbon monoxide and hydrocarbon emission 
standards. This paragraph applies to sources that elect to comply with 
the carbon monoxide and hydrocarbon emissions standards under 
Secs. 63.1203 through 63.1205 by documenting continuous compliance with 
the carbon monoxide standard using a continuous emissions monitoring 
system and documenting compliance with the hydrocarbon standard during 
the destruction and removal efficiency (DRE) performance test or its 
equivalent.
    (i) If a DRE test performed after March 30, 1998 is acceptable as 
documentation of compliance with the DRE standard, you may use the 
highest hourly rolling average hydrocarbon level achieved during those 
DRE test runs to document compliance with the hydrocarbon standard. An 
acceptable DRE test is a test that was used to support successful 
issuance or reissuance of an operating permit under part 270 of this 
chapter.
    (ii) If during this acceptable DRE test you did not obtain 
hydrocarbon emissions data sufficient to document compliance with the 
hydrocarbon standard, you must either:
    (A) Perform, as part of the performance test, an ``equivalent DRE 
test'' to document compliance with the hydrocarbon standard. An 
equivalent DRE test is comprised of a minimum of three runs each with a 
minimum duration of one hour during which you operate the combustor as 
close as reasonably possible to the operating parameter limits that you 
established based on the initial DRE test. You must use the highest 
hourly rolling average hydrocarbon emission level achieved during the 
equivalent DRE test to document compliance with the hydrocarbon 
standard; or (B) Perform a DRE test as part of the performance test.
    (7) Compliance with the DRE standard. (i) Except as provided in 
paragraphs (b)(7)(ii) and (b)(7)(iii) of this section:
    (A) You must document compliance with the Destruction and Removal 
Efficiency (DRE) standard under Secs. 63.1203 through 63.1205 only once 
provided that you do not modify the source after the DRE test in a 
manner that could affect the ability of the source to achieve the DRE 
standard; and
    (B) You may use DRE testing performed after March 30, 1998 for 
purposes of issuance or reissuance of a RCRA permit under part 270 of 
this chapter to document conformance with the DRE standard if you have 
not modified the design or operation of the source since the DRE test 
in a manner that could affect the ability of the source to achieve the 
DRE standard.
    (ii) For sources that feed hazardous waste at a location in the 
combustion system other than the normal flame zone:

[[Page 53046]]

    (A) You must demonstrate compliance with the DRE standard during 
each comprehensive performance test; and
    (B) You may use DRE testing performed after March 30, 1998 for 
purposes of issuance or reissuance of a RCRA permit under part 270 of 
this chapter to document conformance with the DRE standard in lieu of 
DRE testing during the initial comprehensive performance test if you 
have not modified the design or operation of the source since the DRE 
test in a manner that could affect the ability of the source to achieve 
the DRE standard.
    (iii) For sources that do not use DRE testing performed prior to 
the compliance date to document conformance with the DRE standard, you 
must perform DRE testing during the initial comprehensive performance 
test.
    (8) Applicability of particulate matter and opacity standards 
during particulate matter CEMS correlation tests. (i) Any particulate 
matter and opacity standards of parts 60, 61, 63, 264, 265, and 266 of 
this chapter (i.e., any title 40 particulate or opacity standards) 
applicable to a hazardous waste combustor do not apply while you 
conduct particulate matter continuous emissions monitoring system 
(CEMS) correlation tests (i.e., correlation with manual stack methods) 
under the conditions of paragraphs (b)(8)(iii) through (vii) of this 
section.
    (ii) Any permit or other emissions or operating parameter limits or 
conditions, including any limitation on workplace practices, that are 
applicable to hazardous waste combustors to ensure compliance with any 
particulate matter and opacity standards of parts 60, 61, 63, 264, 265, 
and 266 of this chapter (i.e., any title 40 particulate or opacity 
standards) do not apply while you conduct particulate matter CEMS 
correlation tests under the conditions of paragraphs (b)(8)(iii) 
through (vii) of this section.
    (iii) For the provisions of this section to apply, you must:
    (A) Develop a particulate matter CEMS correlation test plan that 
includes the following information. This test plan may be included as 
part of the comprehensive performance test plan required under 
Secs. 63.1207(e) and (f):
    (1) Number of test conditions and number of runs for each test 
condition;
    (2) Target particulate matter emission level for each test 
condition;
    (3) How you plan to modify operations to attain the desired 
particulate matter emission levels; and
    (4) Anticipated normal particulate matter emission levels; and
    (B) Submit the test plan to the Administrator for approval at least 
90 calendar days before the correlation test is scheduled to be 
conducted.
    (iv) The Administrator will review and approve/disapprove the 
correlation test plan under the procedures for review and approval of 
the site-specific test plan provided by Sec. 63.7(c)(3)(i) and (iii). 
If the Administrator fails to approve or disapprove the correlation 
test plan within the time period specified by Sec. 63.7(c)(3)(i), the 
plan is considered approved, unless the Administrator has requested 
additional information.
    (v) The particulate matter and opacity standards and associated 
operating limits and conditions will not be waived for more than 96 
hours, in the aggregate, for a correlation test, including all runs of 
all test conditions.
    (vi) The stack sampling team must be on-site and prepared to 
perform correlation testing no later than 24 hours after you modify 
operations to attain the desired particulate matter emissions 
concentrations, unless you document in the correlation test plan that a 
longer period of conditioning is appropriate.
    (vii) You must return to operating conditions indicative of 
compliance with the applicable particulate matter and opacity standards 
as soon as possible after correlation testing is completed.
    (9) Alternative standards for existing or new hazardous waste 
burning lightweight aggregate kilns using MACT. (i) You may petition 
the Administrator to recommend alternative semivolatile metal, low 
volatile metal, mercury, or hydrochloric acid/chlorine gas emission 
standards if:
    (A) You cannot achieve one or more of these standards while using 
maximum achievable control technology (MACT) because of the raw 
material contribution to emissions of the regulated metals or 
hydrochloric acid/chlorine gas; or
    (B) You determine that mercury is not present at detectable levels 
in your raw material.
    (ii) The alternative standard that you recommend under paragraph 
(b)(9)(i)(A) of this section may be an operating requirement, such as a 
hazardous waste feedrate limitation for metals and/or chlorine, and/or 
an emission limitation.
    (iii) The alternative standard must include a requirement to use 
MACT, or better, applicable to the standard for which the source is 
seeking relief, as defined in paragraphs (b)(9)(viii) and (ix) of this 
section.
    (iv) Documentation required. (A) The alternative standard petition 
you submit under paragraph (b)(9)(i)(A) of this section must include 
data or information documenting that raw material contributions to 
emissions of the regulated metals or hydrochloric acid/chlorine gas 
prevent you from complying with the emission standard even though the 
source is using MACT, as defined in paragraphs (b)(9)(viii) and (ix) of 
this section, for the standard for which you are seeking relief.
    (B) Alternative standard petitions that you submit under paragraph 
(b)(9)(i)(B) of this section must include data or information 
documenting that mercury is not present at detectable levels in raw 
materials.
    (v) You must include data or information with semivolatile metal 
and low volatility metal alternative standard petitions that you submit 
under paragraph (b)(9)(i)(A) of this section documenting that increased 
chlorine feedrates associated with the burning of hazardous waste, when 
compared to non-hazardous waste operations, do not significantly 
increase metal emissions attributable to raw materials.
    (vi) You must include data or information with semivolatile metal, 
low volatile metal, and hydrochloric acid/chlorine gas alternative 
standard petitions that you submit under paragraph (b)(9)(i)(A) of this 
section documenting that semivolatile metal, low volatile metal, and 
hydrochloric acid/chlorine gas emissions attributable to the hazardous 
waste only will not exceed the emission standards in Sec. 63.1205(a) 
and (b).
    (vii) You must not operate pursuant to your recommended alternative 
standards in lieu of emission standards specified in Sec. 63.1205(a) 
and (b):
    (A) Unless the Administrator approves the provisions of the 
alternative standard petition request or establishes other alternative 
standards; and
    (B) Until you submit a revised Notification of Compliance that 
incorporates the revised standards.
    (viii) For purposes of this alternative standard provision, MACT 
for existing hazardous waste burning lightweight aggregate kilns is 
defined as:
    (A) For mercury, a hazardous waste feedrate corresponding to an 
MTEC of 24g/dscm or less;
    (B) For semivolatile metals, a hazardous waste feedrate 
corresponding to an MTEC of 280,000 g/dscm or less, and use of 
a particulate matter control device that achieves particulate matter 
emissions of 57 mg/dscm or less;
    (C) For low volatile metals, a hazardous waste feedrate 
corresponding to an MTEC of 120,000 g/dscm or less, and use of 
a particulate matter control

[[Page 53047]]

device that achieves particulate matter emissions of 57 mg/dscm or 
less; and
    (D) For hydrochloric acid/chlorine gas, a hazardous waste chlorine 
feedrate corresponding to an MTEC of 2,000,000 g/dscm or less, 
and use of an air pollution control device with a hydrochloric acid/
chlorine gas removal efficiency of 85 percent or greater.
    (ix) For purposes of this alternative standard provision, MACT for 
new hazardous waste burning lightweight aggregate kilns is defined as:
    (A) For mercury, a hazardous waste feedrate corresponding to an 
MTEC of 4 g/dscm or less;
    (B) For semivolatile metals, a hazardous waste feedrate 
corresponding to an MTEC of 280,000 g/dscm or less, and use of 
a particulate matter control device that achieves particulate matter 
emissions of 57 mg/dscm or less;
    (C) For low volatile metals, a hazardous waste feedrate 
corresponding to an MTEC of 46,000 g/dscm or less, and use of 
a particulate matter control device that achieves particulate matter 
emissions of 57 mg/dscm or less;
    (D) For hydrochloric acid/chlorine gas, a hazardous waste chlorine 
feedrate corresponding to an MTEC of 14,000,000 g/dscm or 
less, and use of a wet scrubber with a hydrochloric acid/chlorine gas 
removal efficiency of 99.6 percent or greater.
    (10) Alternative standards for existing or new hazardous waste 
burning cement kilns using MACT. (i) You may petition the Administrator 
to recommend alternative semivolatile, low volatile metal, mercury, 
and/or hydrochloric acid/chlorine gas emission standards if:
    (A) You cannot achieve one or more of these standards while using 
maximum achievable control technology (MACT) because of raw material 
contributions to emissions of the regulated metals or hydrochloric 
acid/chlorine gas; or (B) You determine that mercury is not present at 
detectable levels in your raw material.
    (ii) The alternative standard that you recommend under paragraph 
(b)(10)(i)(A) of this section may be an operating requirement, such as 
a hazardous waste feedrate limitation for metals and/or chlorine, and/
or an emission limitation.
    (iii) The alternative standard must include a requirement to use 
MACT, or better, applicable to the standard for which the source is 
seeking relief, as defined in paragraphs (b)(10)(viii) and (ix) of this 
section.
    (iv) Documentation required. (A) The alternative standard petition 
you submit under paragraph (b)(10)(i)(A) of this section must include 
data or information documenting that raw material contributions to 
emissions prevent you from complying with the emission standard even 
though the source is using MACT, as defined in paragraphs (b)(10)(viii) 
and (ix) of this section, for the standard for which you are seeking 
relief.
    (B) Alternative standard petitions that you submit under paragraph 
(b)(10)(i)(B) of this section must include data or information 
documenting that mercury is not present at detectable levels in raw 
materials.
    (v) You must include data or information with semivolatile metal 
and low volatile metal alternative standard petitions that you submit 
under paragraph (b)(10)(i)(A) of this section documenting that 
increased chlorine feedrates associated with the burning of hazardous 
waste, when compared to non-hazardous waste operations, do not 
significantly increase metal emissions attributable to raw materials.
    (vi) You must include data or information with semivolatile metal, 
low volatile metal, and hydrochloric acid/chlorine gas alternative 
standard petitions that you submit under paragraph (b)(10)(i)(A) of 
this section documenting that emissions of the regulated metals and 
hydrochloric acid/chlorine gas attributable to the hazardous waste only 
will not exceed the emission standards in Sec. 63.1204(a) and (b).
    (vii) You must not operate pursuant to your recommended alternative 
standards in lieu of emission standards specified in Sec. 63.1204(a) 
and (b):
    (A) Unless the Administrator approves the provisions of the 
alternative standard petition request or establishes other alternative 
standards; and
    (B) Until you submit a revised Notification of Compliance that 
incorporates the revised standards.
    (viii) For purposes of this alternative standard provision, MACT 
for existing hazardous waste burning cement kilns is defined as:
    (A) For mercury, a hazardous waste feedrate corresponding to an 
MTEC of 88g/dscm or less;
    (B) For semivolatile metals, a hazardous waste feedrate 
corresponding to an MTEC of 31,000 g/dscm or less, and use of 
a particulate matter control device that achieves particulate matter 
emissions of 0.15 kg/Mg dry feed or less;
    (C) For low volatile metals, a hazardous waste feedrate 
corresponding to an MTEC of 54,000 g/dscm or less, and use of 
a particulate matter control device that achieves particulate matter 
emissions of 0.15 kg/Mg dry feed or less; and
    (D) For hydrochloric acid/chlorine gas, a hazardous waste chlorine 
feedrate corresponding to an MTEC of 720,000 g/dscm or less.
    (ix) For purposes of this alternative standard provision, MACT for 
new hazardous waste burning cement kilns is defined as:
    (A) For mercury, a hazardous waste feedrate corresponding to an 
MTEC of 7 g/dscm or less;
    (B) For semivolatile metals, a hazardous waste feedrate 
corresponding to an MTEC of 31,000 g/dscm or less, and use of 
a particulate matter control device that achieves particulate matter 
emissions of 0.15 kg/Mg dry feed or less;
    (C) For low volatile metals, a hazardous waste feedrate 
corresponding to an MTEC of 15,000 g/dscm or less, and use of 
a particulate matter control device that achieves particulate matter 
emissions of 0.15 kg/Mg dry feed or less;
    (D) For hydrochloric acid/chlorine gas, a hazardous waste chlorine 
feedrate corresponding to an MTEC of 420,000 g/dscm or less.
    (11) Calculation of hazardous waste residence time. You must 
calculate the hazardous waste residence time and include the 
calculation in the performance test plan under Sec. 63.1207(f) and the 
operating record. You must also provide the hazardous waste residence 
time in the Documentation of Compliance under Sec. 63.1211(d) and the 
Notification of Compliance under Secs. 63.1207(j) and 63.1210(d).
    (12) Documenting compliance with the standards based on performance 
testing. (i) You must conduct a minimum of three runs of a performance 
test required under Sec. 63.1207 to document compliance with the 
emission standards of this subpart.
    (ii) You must document compliance with the emission standards based 
on the arithmetic average of the emission results of each run, except 
that you must document compliance with the destruction and removal 
efficiency standard for each run of the comprehensive performance test 
individually.
    (13) Cement kilns and lightweight aggregate kilns that feed 
hazardous waste at a location other than the end where products are 
normally discharged and where fuels are normally fired. (i) Cement 
kilns that feed hazardous waste at a location other than the end where 
products are normally discharged and where fuels are normally fired 
must comply with the hydrocarbon standards of Sec. 63.1204 as follows:
    (A) Existing sources must comply with the 20 parts per million by 
volume hydrocarbon standard in the main stack under 
Sec. 63.1204(a)(5)(ii)(A);

[[Page 53048]]

    (B) New sources must comply with the 20 parts per million by volume 
hydrocarbon standard in the main stack under Sec. 63.1204(b)(5)(ii)(A).
    (ii) Lightweight aggregate kilns that feed hazardous waste at a 
location other than the end where products are normally discharged and 
where fuels are normally fired must comply with the hydrocarbon 
standards of Sec. 63.1205 as follows:
    (A) Existing sources must comply with the 20 parts per million by 
volume hydrocarbon standard under Sec. 63.1205(a)(5)(ii);
    (B) New sources must comply with the 20 parts per million by volume 
hydrocarbon standard under Sec. 63.1205(b)(5)(ii).
    (14) Alternative particulate matter standard for incinerators with 
de minimis metals. (i) General. You may petition the Administrator for 
an alternative particulate matter standard of 68 mg/dscm, corrected to 
7% oxygen, if you meet the de minimis metals criteria of paragraph 
(b)(14)(ii) of this section.
    (ii) Documentation required. The alternative standard petition you 
submit under paragraph (b)(14)(i) of this section must include data or 
information documenting that:
    (A) Your feedstreams do not contain detectable levels of antimony, 
cobalt, manganese, nickel, selenium, lead, cadmium, chromium, arsenic 
and beryllium;
    (B) Your combined uncontrolled lead, cadmium and selenium 
emissions, when assuming these metals are present in your feedstreams 
at one-half the detection limit, are below 240 ug/dscm, corrected to 7% 
oxygen.
    (C) Your combined uncontrolled antimony, cobalt, manganese, nickel, 
chromium, arsenic and beryllium emissions, when assuming these metals 
are present in your feedstreams at one-half the detection limit, are 
below 97 ug/dscm, corrected to 7% oxygen.
    (iii) Frequency of analysis. You must sample and analyze your 
feedstreams at least annually to document that you meet the de minimis 
criteria in paragraph (b)(14)(ii) of this section.
    (iv) You must not operate pursuant to this alternative standard 
unless the Administrator determines and provides written confirmation 
that you meet the eligibility requirements in paragraph (b)(14)(ii) of 
this section.
    (c) Operating requirements.--(1) General. (i) You must operate only 
under the operating requirements specified in the Documentation of 
Compliance under Sec. 63.1211(d) or the Notification of Compliance 
under Secs. 63.1207(j) and 63.1210(d), except:
    (A) During performance tests under approved test plans according to 
Sec. 63.1207(e), (f), and (g), and
    (B) Under the conditions of paragraph (b)(1)(i) or (ii) of this 
section;
    (ii) The Documentation of Compliance and the Notification of 
Compliance must contain operating requirements including, but not 
limited to, the operating requirements in this section and Sec. 63.1209
    (iii) Failure to comply with the operating requirements is failure 
to ensure compliance with the emission standards of this subpart;
    (iv) Operating requirements in the Notification of Compliance are 
applicable requirements for purposes of parts 70 and 71 of this 
chapter;
    (v) The operating requirements specified in the Notification of 
Compliance will be incorporated in the title V permit.
    (2) Startup, shutdown, and malfunction plan. (i) Except as provided 
by paragraph (c)(2)(ii) of this section, you are subject to the 
startup, shutdown, and malfunction plan requirements of 
Sec. 63.6(e)(3).
    (ii) Even if you follow the startup and shutdown procedures and the 
corrective measures upon a malfunction that are prescribed in the 
startup, shutdown, and malfunction plan, the emission standards and 
operating requirements of this subpart apply if hazardous waste is in 
the combustion chamber (i.e., if you are feeding hazardous waste or if 
startup, shutdown, or a malfunction occurs before the hazardous waste 
residence time has transpired after hazardous waste cutoff).
    (iii) You must identify in the plan a projected oxygen correction 
factor based on normal operations to use during periods of startup and 
shutdown.
    (iv) You must record the plan in the operating record.
    (3) Automatic waste feed cutoff (AWFCO).-- (i) General. Upon the 
compliance date, you must operate the hazardous waste combustor with a 
functioning system that immediately and automatically cuts off the 
hazardous waste feed, except as provided by paragraph (c)(3)(viii) of 
this section:
    (A) When any of the following are exceeded: Operating parameter 
limits specified under Sec. 63.1209; an emission standard monitored by 
a CEMS; and the allowable combustion chamber pressure;
    (B) When the span value of any CMS detector, except a CEMS, is met 
or exceeded;
    (C) Upon malfunction of a CMS monitoring an operating parameter 
limit specified under Sec. 63.1209 or an emission level; or
    (D) When any component of the automatic waste feed cutoff system 
fails.
    (ii) Ducting of combustion gases. During an AWFCO, you must 
continue to duct combustion gasses to the air pollution control system 
while hazardous waste remains in the combustion chamber (i.e., if the 
hazardous waste residence time has not transpired since the hazardous 
waste feed cutoff system was activated).
    (iii) Restarting waste feed. You must continue to monitor during 
the cutoff the operating parameters for which limits are established 
under Sec. 63.1209 and the emissions required under that section to be 
monitored by a CEMS, and you must not restart the hazardous waste feed 
until the operating parameters and emission levels are within the 
specified limits.
    (iv) Failure of the AWFCO system. If the AWFCO system fails to 
automatically and immediately cutoff the flow of hazardous waste upon 
exceedance of parameter required to be interlocked with the AWFCO 
system under paragraph (c)(3)(i) of this section, you have failed to 
comply with the AWFCO requirements of paragraph (c)(3) of this section.
    (v) Corrective measures. If, after any AWFCO, there is an 
exceedance of an emission standard or operating requirement, 
irrespective of whether the exceedance occurred while hazardous waste 
remained in the combustion chamber (i.e., whether the hazardous waste 
residence time has transpired since the hazardous waste feed cutoff 
system was activated), you must investigate the cause of the AWFCO, 
take appropriate corrective measures to minimize future AWFCOs, and 
record the findings and corrective measures in the operating record.
    (vi) Excessive exceedance reporting. (A) For each set of 10 
exceedances of an emission standard or operating requirement while 
hazardous waste remains in the combustion chamber (i.e., when the 
hazardous waste residence time has not transpired since the hazardous 
waste feed was cutoff) during a 60-day block period, you must submit to 
the Administrator a written report within 5 calendar days of the 10th 
exceedance documenting the exceedances and results of the investigation 
and corrective measures taken.
    (B) On a case-by-case basis, the Administrator may require 
excessive exceedance reporting when fewer than 10 exceedances occur 
during a 60-day block period.
    (vii) Testing. The AWFCO system and associated alarms must be 
tested at least weekly to verify operability, unless you

[[Page 53049]]

document in the operating record that weekly inspections will unduly 
restrict or upset operations and that less frequent inspection will be 
adequate. At a minimum, you must conduct operability testing at least 
monthly. You must document and record in the operating record AWFCO 
operability test procedures and results.
    (viii) Ramping down waste feed. (A) You may ramp down the waste 
feedrate of pumpable hazardous waste over a period not to exceed one 
minute, except as provided by paragraph (c)(3)(viii)(B) of this 
section. If you elect to ramp down the waste feed, you must document 
ramp down procedures in the operating and maintenance plan. The 
procedures must specify that the ramp down begins immediately upon 
initiation of automatic waste feed cutoff and the procedures must 
prescribe a bona fide ramping down. If an emission standard or 
operating limit is exceeded during the ramp down, you have failed to 
comply with the emission standards or operating requirements of this 
subpart.
    (B) If the automatic waste feed cutoff is triggered by an 
exceedance of any of the following operating limits, you may not ramp 
down the waste feed cutoff: Minimum combustion chamber temperature, 
maximum hazardous waste feedrate, or any hazardous waste firing system 
operating limits that may be established for your combustor.
    (4) ESV openings.--(i) Failure to meet standards. If an emergency 
safety vent (ESV) opens when hazardous waste remains in the combustion 
chamber (i.e., when the hazardous waste residence time has not 
transpired since the hazardous waste feed cutoff system was activated) 
such that combustion gases are not treated as during the most recent 
comprehensive performance test (e.g., if the combustion gas by-passes 
any emission control device that was operating during the performance 
test), it is evidence of your failure to comply with the emission 
standards of this subpart.
    (ii) ESV operating plan. (A) You must develop an ESV operating 
plan, comply with the operating plan, and keep the plan in the 
operating record.
    (B) The ESV operating plan must provide detailed procedures for 
rapidly stopping the waste feed, shutting down the combustor, and 
maintaining temperature and negative pressure in the combustion chamber 
during the hazardous waste residence time, if feasible. The plan must 
include calculations and information and data documenting the 
effectiveness of the plan's procedures for ensuring that combustion 
chamber temperature and negative pressure are maintained as is 
reasonably feasible.
    (iii) Corrective measures. After any ESV opening that results in a 
failure to meet the emission standards as defined in paragraph 
(c)(4)(i) of this section, you must investigate the cause of the ESV 
opening, take appropriate corrective measures to minimize such future 
ESV openings, and record the findings and corrective measures in the 
operating record.
    (iv) Reporting requirement. You must submit to the Administrator a 
written report within 5 days of an ESV opening that results in failure 
to meet the emission standards of this subpart (as defined in paragraph 
(c)(4)(i) of this section) documenting the result of the investigation 
and corrective measures taken.
    (5) Combustion system leaks. (i) Combustion system leaks of 
hazardous air pollutants must be controlled by:
    (A) Keeping the combustion zone sealed to prevent combustion system 
leaks; or
    (B) Maintaining the maximum combustion zone pressure lower than 
ambient pressure using an instantaneous monitor; or
    (C) Upon prior written approval of the Administrator, an 
alternative means of control to provide control of combustion system 
leaks equivalent to maintenance of combustion zone pressure lower than 
ambient pressure; and
    (ii) You must specify in the operating record the method used for 
control of combustion system leaks.
    (6) Operator training and certification. (i) You must establish a 
training and certification program for each person who has 
responsibilities affecting operations that may affect emissions of 
hazardous air pollutants from the source. Such persons include, but are 
not limited to, chief facility operators, control room operators, 
continuous monitoring system operators, persons that sample and analyze 
feedstreams, persons that manage and charge feedstreams to the 
combustor, persons that operate emission control devices, ash and waste 
handlers, and maintenance personnel.
    (ii) You must ensure that the source is operated and maintained at 
all times by persons who are trained and certified to perform these and 
any other duties that may affect emissions of hazardous air pollutants.
    (iii) For hazardous waste incinerators, the training and 
certification program must conform to a state-approved training and 
certification program or, if there is no such state program, to the 
American Society of Mechanical Engineers Standard Number QHO-1-1994.
    (iv) For hazardous waste burning cement and lightweight aggregate 
kilns, the training and certification program must be approved by the 
state or the Administrator, and must be complete and reliable and 
conform to principles of good operator and operating practices 
(including training and certification).
    (v) You must record the operator training and certification program 
in the operating record.
    (7) Operation and maintenance plan.--(i) General. (A) You must 
prepare and at all times operate according to an operation and 
maintenance plan that describes in detail procedures for operation, 
inspection, maintenance, and corrective measures for all components of 
the combustor, including associated pollution control equipment, that 
could affect emissions of regulated hazardous air pollutants.
    (B) The plan must prescribe how you will operate and maintain the 
combustor in a manner consistent with good air pollution control 
practices for minimizing emissions at least to the levels achieved 
during the comprehensive performance test.
    (C) This plan ensures compliance with the operation and maintenance 
requirements of Sec. 63.6(e) and minimizes emissions of pollutants, 
automatic waste feed cutoffs, and malfunctions.
    (D) You must record the plan in the operating record.
    (ii) Requirements for baghouses at lightweight aggregate kilns and 
incinerators. If you own or operate a hazardous waste incinerator or 
hazardous waste burning lightweight aggregate kiln equipped with a 
baghouse (fabric filter), you must prepare and at all times operate 
according to an operations and maintenance plan that describes in 
detail procedures for inspection, maintenance, and bag leak detection 
and corrective measures for each baghouse used to comply with the 
standards under this subpart.
    (A) The operation and maintenance plan for baghouses must be 
submitted to the Administrator with the initial comprehensive 
performance test plan for review and approval.
    (B) The procedures specified in the operations and maintenance plan 
for inspections and routine maintenance of a baghouse must, at a 
minimum, include the following requirements:
    (1) Daily visual observation of baghouse discharge or stack;
    (2) Daily confirmation that dust is being removed from hoppers 
through visual inspection, or equivalent means

[[Page 53050]]

of ensuring the proper functioning of removal mechanisms;
    (3) Daily check of compressed air supply for pulse-jet baghouses;
    (4) Daily visual inspection of isolation dampers for proper 
operation;
    (5) An appropriate methodology for monitoring cleaning cycles to 
ensure proper operation;
    (6) Weekly check of bag cleaning mechanisms for proper functioning 
through visual inspection or equivalent means;
    (7) Weekly check of bag tension on reverse air and shaker-type 
baghouses. Such checks are not required for shaker-type baghouses using 
self-tensioning (spring loaded) devices;
    (8) Monthly confirmation of the physical integrity of the baghouse 
through visual inspection of the baghouse interior for air leaks;
    (9) Monthly inspection of bags and bag connections;
    (10) Quarterly inspection of fans for wear, material buildup, and 
corrosion through visual inspection, vibration detectors, or equivalent 
means; and
    (11) Continuous operation of a bag leak detection system as a 
continuous monitor.
    (C) The procedures for maintenance specified in the operation and 
maintenance plan must, at a minimum, include a preventative maintenance 
schedule that is consistent with the baghouse manufacturer's 
instructions for routine and long-term maintenance.
    (D) The bag leak detection system required by paragraph 
(c)(7)(ii)(B)(11) of this section must meet the following 
specifications and requirements:
    (1) The bag leak detection system must be certified by the 
manufacturer to be capable of continuously detecting and recording 
particulate matter emissions at concentrations of 1.0 milligram per 
actual cubic meter or less;
    (2) The bag leak detection system sensor must provide output of 
relative particulate matter loadings;
    (3) The bag leak detection system must be equipped with an alarm 
system that will sound an audible alarm when an increase in relative 
particulate loadings is detected over a preset level;
    (4) The bag leak detection system shall be installed and operated 
in a manner consistent with available written guidance from the U.S. 
Environmental Protection Agency or, in the absence of such written 
guidance, the manufacturer's written specifications and recommendations 
for installation, operation, and adjustment of the system;
    (5) The initial adjustment of the system shall, at a minimum, 
consist of establishing the baseline output by adjusting the 
sensitivity (range) and the averaging period of the device, and 
establishing the alarm set points and the alarm delay time;
    (6) Following initial adjustment, you must not adjust the 
sensitivity or range, averaging period, alarm set points, or alarm 
delay time, except as detailed in the operation and maintenance plan 
required under paragraph (c)(7)(ii)(A) of this section. You must not 
increase the sensitivity by more than 100 percent or decrease the 
sensitivity by more than 50 percent over a 365 day period unless such 
adjustment follows a complete baghouse inspection which demonstrates 
the baghouse is in good operating condition;
    (7) For negative pressure or induced air baghouses, and positive 
pressure baghouses that are discharged to the atmosphere through a 
stack, the bag leak detector must be installed downstream of the 
baghouse and upstream of any wet acid gas scrubber; and
    (8) Where multiple detectors are required, the system's 
instrumentation and alarm system may be shared among the detectors.
    (E) The operation and maintenance plan required by paragraph 
(c)(7)(ii) of this section must include a corrective measures plan that 
specifies the procedures you will follow in the case of a bag leak 
detection system alarm. The corrective measures plan must include, at a 
minimum, the procedures used to determine and record the time and cause 
of the alarm as well as the corrective measures taken to correct the 
control device malfunction or minimize emissions as specified below. 
Failure to initiate the corrective measures required by this paragraph 
is failure to ensure compliance with the emission standards in this 
subpart.
    (1) You must initiate the procedures used to determine the cause of 
the alarm within 30 minutes of the time the alarm first sounds; and
    (2) You must alleviate the cause of the alarm by taking the 
necessary corrective measure(s) which may include, but are not to be 
limited to, the following measures:
    (i) Inspecting the baghouse for air leaks, torn or broken filter 
elements, or any other malfunction that may cause an increase in 
emissions;
    (ii) Sealing off defective bags or filter media;
    (iii) Replacing defective bags or filter media, or otherwise 
repairing the control device;
    (iv) Sealing off a defective baghouse compartment;
    (v) Cleaning the bag leak detection system probe, or otherwise 
repairing the bag leak detection system; or
    (vi) Shutting down the combustor.


Sec. 63.1207  What are the performance testing requirements?

    (a) General. The provisions of Sec. 63.7 apply, except as noted 
below.
    (b) Types of performance tests--(1) Comprehensive performance test. 
You must conduct comprehensive performance tests to demonstrate 
compliance with the emission standards provided by Secs. 63.1203, 
63.1204, and 63.1205, establish limits for the operating parameters 
provided by Sec. 63.1209, and demonstrate compliance with the 
performance specifications for continuous monitoring systems.
    (2) Confirmatory performance test. You must conduct confirmatory 
performance tests to:
    (i) Demonstrate compliance with the dioxin/furan emission standard 
when the source operates under normal operating conditions; and
    (ii) Conduct a performance evaluation of continuous monitoring 
systems required for compliance assurance with the dioxin/furan 
emission standard under Sec. 63.1209(k).
    (c) Initial comprehensive performance test--(1) Test date. Except 
as provided by paragraph (c)(2) of this section, you must commence the 
initial comprehensive performance test not later than six months after 
the compliance date.
    (2) Data in lieu of the initial comprehensive performance test. (i) 
You may request that previous emissions test data serve as 
documentation of conformance with the emission standards of this 
subpart provided that the previous testing was:
    (A) Initiated after March 30, 1998;
    (B) For the purpose of demonstrating emissions under a RCRA permit 
issuance or reissuance proceeding under part 270 of this chapter;
    (C) In conformance with the requirements of paragraph (g)(1) of 
this section; and
    (D) Sufficient to establish the applicable operating parameter 
limits under Sec. 63.1209.
    (ii) You must submit data in lieu of the initial comprehensive 
performance test in lieu of (i.e., if the data are in lieu of all 
performance testing) or with the notification of performance test 
required under paragraph (e) of this section.
    (d) Frequency of testing. You must conduct testing periodically as 
prescribed in paragraphs (d)(1) through (3) of this section. The date 
of commencement of the initial comprehensive performance test is the 
basis for establishing the deadline to commence the initial 
confirmatory performance test and the next

[[Page 53051]]

comprehensive performance test. You may conduct performance testing at 
any time prior to the required date. The deadline for commencing 
subsequent confirmatory and comprehensive performance testing is based 
on the date of commencement of the previous comprehensive performance 
test. Unless the Administrator grants a time extension under paragraph 
(i) of this section, you must conduct testing as follows:
    (1) Comprehensive performance testing. You must commence testing no 
later than 61 months after the date of commencing the previous 
comprehensive performance test. If you submit data in lieu of the 
initial performance test, you must commence the subsequent 
comprehensive performance test within 61 months of the date six months 
after the compliance date.
    (2) Confirmatory performance testing. You must commence 
confirmatory performance testing no later than 31 months after the date 
of commencing the previous comprehensive performance test. If you 
submit data in lieu of the initial performance test, you must commence 
the initial confirmatory performance test within 31 months of the date 
six months after the compliance date. To ensure that the confirmatory 
test is conducted approximately midway between comprehensive 
performance tests, the Administrator will not approve a test plan that 
schedules testing within 18 months of commencing the previous 
comprehensive performance test.
    (3) Duration of testing. You must complete performance testing 
within 60 days after the date of commencement, unless the Administrator 
determines that a time extension is warranted based on your 
documentation in writing of factors beyond your control that prevent 
you from meeting the 60-day deadline.
    (e) Notification of performance test and CMS performance 
evaluation, and approval of test plan and CMS performance evaluation 
plan. (1) The provisions of Sec. 63.7(b) and (c) and Sec. 63.8(e) 
apply, except:
    (i) Comprehensive performance test. You must submit to the 
Administrator a notification of your intention to conduct a 
comprehensive performance test and CMS performance evaluation and a 
site-specific test plan and CMS performance evaluation plan at least 
one year before the performance test and performance evaluation are 
scheduled to begin.
    (A) The Administrator will notify you of approval or intent to deny 
approval of the test plan and CMS performance evaluation plan within 9 
months after receipt of the original plan.
    (B) You must submit to the Administrator a notification of your 
intention to conduct the comprehensive performance test at least 60 
calendar days before the test is scheduled to begin.
    (ii) Confirmatory performance test. You must submit to the 
Administrator a notification of your intention to conduct a 
confirmatory performance test and CMS performance evaluation and a test 
plan and CMS performance evaluation plan at least 60 calendar days 
before the performance test is scheduled to begin. The Administrator 
will notify you of approval or intent to deny approval of the test and 
CMS performance evaluation plans within 30 calendar days after receipt 
of the original plans.
    (2) After the Administrator has approved the test and CMS 
performance evaluation plans, you must make the plans available to the 
public for review. You must issue a public notice announcing the 
approval of the plans and the location where the plans are available 
for review.
    (f) Content of performance test plan. The provisions of 
Secs. 63.7(c)(2)(i)-(iii) and (v) regarding the content of the test 
plan apply. In addition, you must include the following information in 
the test plan:
    (1) Content of comprehensive performance test plan. (i) An analysis 
of each feedstream, including hazardous waste, other fuels, and 
industrial furnace feedstocks, as fired, that includes:
    (A) Heating value, levels of ash (for hazardous waste incinerators 
only), levels of semivolatile metals, low volatile metals, mercury, and 
total chlorine (organic and inorganic); and
    (B) Viscosity or description of the physical form of the 
feedstream;
    (ii) For organic hazardous air pollutants established by 42 U.S.C. 
7412(b)(1), excluding caprolactam (CAS number 105602) as provided by 
Sec. 63.60:
    (A) An identification of such organic hazardous air pollutants that 
are present in the feedstream, except that you need not analyze for 
organic hazardous air pollutants that would reasonably not be expected 
to be found in the feedstream. You must identify any constituents you 
exclude from analysis and explain the basis for excluding them. You 
must conduct the feedstream analysis according to Sec. 63.1208(g);
    (B) An approximate quantification of such identified organic 
hazardous air pollutants in the feedstreams, within the precision 
produced by the analytical procedures of Sec. 63.1208(g); and
    (C) A description of blending procedures, if applicable, prior to 
firing the feedstream, including a detailed analysis of the materials 
prior to blending, and blending ratios;
    (iii) A detailed engineering description of the hazardous waste 
combustor, including:
    (A) Manufacturer's name and model number of the hazardous waste 
combustor;
    (B) Type of hazardous waste combustor;
    (C) Maximum design capacity in appropriate units;
    (D) Description of the feed system for each feedstream;
    (E) Capacity of each feed system;
    (F) Description of automatic hazardous waste feed cutoff system(s);
    (G) Description of the design, operation, and maintenance practices 
for any air pollution control system; and
    (H) Description of the design, operation, and maintenance practices 
of any stack gas monitoring and pollution control monitoring systems;
    (iv) A detailed description of sampling and monitoring procedures 
including sampling and monitoring locations in the system, the 
equipment to be used, sampling and monitoring frequency, and planned 
analytical procedures for sample analysis;
    (v) A detailed test schedule for each hazardous waste for which the 
performance test is planned, including date(s), duration, quantity of 
hazardous waste to be burned, and other relevant factors;
    (vi) A detailed test protocol, including, for each hazardous waste 
identified, the ranges of hazardous waste feedrate for each feed 
system, and, as appropriate, the feedrates of other fuels and 
feedstocks, and any other relevant parameters that may affect the 
ability of the hazardous waste combustor to meet the emission 
standards;
    (vii) A description of, and planned operating conditions for, any 
emission control equipment that will be used;
    (viii) Procedures for rapidly stopping the hazardous waste feed and 
controlling emissions in the event of an equipment malfunction;
    (ix) A determination of the hazardous waste residence time;
    (x) If you are requesting to extrapolate metal feedrate limits from 
comprehensive performance test levels:
    (A) A description of the extrapolation methodology and rationale 
for how the approach ensures compliance with the emission standards;
    (B) Documentation of the historical range of normal (i.e., other 
than during compliance testing) metals feedrates for each feedstream;
    (C) Documentation that the level of spiking recommended during the

[[Page 53052]]

performance test will mask sampling and analysis imprecision and 
inaccuracy to the extent that extrapolation of feedrates and emission 
rates from performance test data will be as accurate and precise as if 
full spiking were used;
    (xi) If you do not continuously monitor regulated constituents in 
natural gas, process air feedstreams, and feedstreams from vapor 
recovery systems, you must include documentation of the expected levels 
of regulated constituents in those feedstreams;
    (xii) Documentation justifying the duration of system conditioning 
required to ensure the combustor has achieved steady-state operations 
under performance test operating conditions, as provided by paragraph 
(g)(1)(iii) of this section; and
    (xiii) Such other information as the Administrator reasonably finds 
necessary to determine whether to approve the performance test plan.
    (2) Content of confirmatory test plan. (i) A description of your 
normal hydrocarbon or carbon monoxide operating levels, as specified in 
paragraph (g)(2)(i) of this section, and an explanation of how these 
normal levels were determined;
    (ii) A description of your normal applicable operating parameter 
levels, as specified in paragraph (g)(2)(ii) of this section, and an 
explanation of how these normal levels were determined;
    (iii) A description of your normal chlorine operating levels, as 
specified in paragraph (g)(2)(iii) of this section, and an explanation 
of how these normal levels were determined;
    (iv) If you use carbon injection or a carbon bed, a description of 
your normal cleaning cycle of the particulate matter control device, as 
specified in paragraph (g)(2)(iv) of this section, and an explanation 
of how these normal levels were determined;
    (v) A detailed description of sampling and monitoring procedures 
including sampling and monitoring locations in the system, the 
equipment to be used, sampling and monitoring frequency, and planned 
analytical procedures for sample analysis;
    (vi) A detailed test schedule for each hazardous waste for which 
the performance test is planned, including date(s), duration, quantity 
of hazardous waste to be burned, and other relevant factors;
    (vii) A detailed test protocol, including, for each hazardous waste 
identified, the ranges of hazardous waste feedrate for each feed 
system, and, as appropriate, the feedrates of other fuels and 
feedstocks, and any other relevant parameters that may affect the 
ability of the hazardous waste combustor to meet the dioxin/furan 
emission standard;
    (viii) A description of, and planned operating conditions for, any 
emission control equipment that will be used;
    (ix) Procedures for rapidly stopping the hazardous waste feed and 
controlling emissions in the event of an equipment malfunction; and
    (x) Such other information as the Administrator reasonably finds 
necessary to determine whether to approve the confirmatory test plan.
    (g) Operating conditions during testing. You must comply with the 
provisions of Sec. 63.7(e). Conducting performance testing under 
operating conditions representative of the extreme range of normal 
conditions is consistent with the requirement of Sec. 63.7(e)(1) to 
conduct performance testing under representative operating conditions.
    (1) Comprehensive performance testing.--(i) Operations during 
testing. For the following parameters, you must operate the combustor 
during the performance test under normal conditions (or conditions that 
will result in higher than normal emissions):
    (A) Chlorine feedrate. You must feed normal (or higher) levels of 
chlorine during the dioxin/furan performance test;
    (B) Ash feedrate. For hazardous waste incinerators, you must 
conduct the following tests when feeding normal (or higher) levels of 
ash: The semivolatile metal and low volatile metal performance tests; 
and the dioxin/furan and mercury performance tests if activated carbon 
injection or a carbon bed is used; and
    (C) Cleaning cycle of the particulate matter control device. You 
must conduct the following tests when the particulate matter control 
device undergoes its normal (or more frequent) cleaning cycle: The 
particulate matter, semivolatile metal, and low volatile metal 
performance tests; and the dioxin/furan and mercury performance tests 
if activated carbon injection or a carbon bed is used.
    (ii) Modes of operation. Given that you must establish limits for 
the applicable operating parameters specified in Sec. 63.1209 based on 
operations during the comprehensive performance test, you may conduct 
testing under two or more operating modes to provide operating 
flexibility.
    (iii) Steady-state conditions. (A) Prior to obtaining performance 
test data, you must operate under performance test conditions until you 
reach steady-state operations with respect to emissions of pollutants 
you must measure during the performance test and operating parameters 
under Sec. 63.1209 for which you must establish limits. During system 
conditioning, you must ensure that each operating parameter for which 
you must establish a limit is held at the level planned for the 
performance test. You must include documentation in the performance 
test plan under paragraph (f) of this section justifying the duration 
of system conditioning.
    (B) If you own or operate a hazardous waste cement kiln that 
recycles collected particulate matter (i.e., cement kiln dust) into the 
kiln, you must sample and analyze the recycled particulate matter prior 
to obtaining performance test data for levels of selected metals that 
must be measured during performance testing to document that the system 
has reached steady-state conditions (i.e., that metals levels have 
stabilized). You must document the rationale for selecting metals that 
are indicative of system equilibrium and include the information in the 
performance test plan under paragraph (f) of this section. To determine 
system equilibrium, you must sample and analyze the recycled 
particulate matter hourly for each selected metal, unless you submit in 
the performance test plan a justification for reduced sampling and 
analysis and the Administrator approves in writing a reduced sampling 
and analysis frequency.
    (2) Confirmatory performance testing. You must conduct confirmatory 
performance testing for dioxin/furan under normal operating conditions 
for the following parameters:
    (i) Carbon monoxide (or hydrocarbon) CEMS emission levels must be 
within the range of the average value to the maximum value allowed. The 
average value is defined as the sum of the hourly rolling average 
values recorded (each minute) over the previous 12 months divided by 
the number of rolling averages recorded during that time;
    (ii) Each operating limit (specified in Sec. 63.1209) established 
to maintain compliance with the dioxin/furan emission standard must be 
held within the range of the average value over the previous 12 months 
and the maximum or minimum, as appropriate, that is allowed. The 
average value is defined as the sum of the rolling average values 
recorded over the previous 12 months divided by the number of rolling 
averages recorded during that time. The average value must not include 
calibration data, malfunction data, and data obtained when not burning 
hazardous waste;
    (iii) You must feed chlorine at normal feedrates or greater; and 
(iv) If the

[[Page 53053]]

combustor is equipped with carbon injection or carbon bed, normal 
cleaning cycle of the particulate matter control device.
    (h) Operating conditions during subsequent testing. (1) Current 
operating parameter limits established under Sec. 63.1209 are waived 
during subsequent comprehensive performance testing under an approved 
test plan.
    (2) Current operating parameter limits are also waived during 
pretesting prescribed in the approved test plan prior to comprehensive 
performance testing for an aggregate time not to exceed 720 hours of 
operation. Pretesting means:
    (i) Operations when stack emissions testing for dioxin/furan, 
mercury, semivolatile metals, low volatile metals, particulate matter, 
or hydrochloric acid/chlorine gas is being performed; and
    (ii) Operations to reach steady-state operating conditions prior to 
stack emissions testing under paragraph (g)(1)(iii) of this section.
    (i) Time extension for subsequent performance tests. After the 
initial comprehensive performance test, you may request up to a one-
year time extension for conducting a comprehensive or confirmatory 
performance test to consolidate performance testing with other state or 
federally required emission testing, or for other reasons deemed 
acceptable by the Administrator. If the Administrator grants a time 
extension for a comprehensive performance test, the deadlines for 
commencing the next comprehensive and confirmatory tests are based on 
the date that the subject comprehensive performance test commences.
    (1) You must submit in writing to the Administrator any request 
under this paragraph for a time extension for conducting a performance 
test.
    (2) You must include in the request for an extension for conducting 
a performance test the following:
    (i) A description of the reasons for requesting the time extension;
    (ii) The date by which you will commence performance testing.
    (3) The Administrator will notify you in writing of approval or 
intention to deny approval of your request for an extension for 
conducting a performance test within 30 calendar days after receipt of 
sufficient information to evaluate your request. The 30-day approval or 
denial period will begin after you have been notified in writing that 
your application is complete. The Administrator will notify you in 
writing whether the application contains sufficient information to make 
a determination within 30 calendar days after receipt of the original 
application and within 30 calendar days after receipt of any 
supplementary information that you submit.
    (4) When notifying you that your application is not complete, the 
Administrator will specify the information needed to complete the 
application. The Administrator will also provide notice of opportunity 
for you to present, in writing, within 30 calendar days after 
notification of the incomplete application, additional information or 
arguments to the Administrator to enable further action on the 
application.
    (5) Before denying any request for an extension for performance 
testing, the Administrator will notify you in writing of the 
Administrator's intention to issue the denial, together with:
    (i) Notice of the information and findings on which the intended 
denial is based; and
    (ii) Notice of opportunity for you to present in writing, within 15 
calendar days after notification of the intended denial, additional 
information or arguments to the Administrator before further action on 
the request.
    (6) The Administrator's final determination to deny any request for 
an extension will be in writing and will set forth specific grounds 
upon which the denial is based. The final determination will be made 
within 30 calendar days after the presentation of additional 
information or argument (if the application is complete), or within 30 
calendar days after the final date specified for the presentation if no 
presentation is made.
    (j) Notification of compliance.--(1) Comprehensive performance 
test. (i) Except as provided by paragraph (j)(4) of this section, 
within 90 days of completion of a comprehensive performance test, you 
must postmark a Notification of Compliance documenting compliance or 
noncompliance with the emission standards and continuous monitoring 
system requirements, and identifying operating parameter limits under 
Sec. 3.1209.
    (ii) Upon postmark of the Notification of Compliance, you must 
comply with all operating requirements specified in the Notification of 
Compliance in lieu of the limits specified in the Documentation of 
Compliance required under Sec. 63.1211(d).
    (2) Confirmatory performance test. Except as provided by paragraph 
(j)(4) of this section, within 90 days of completion of a confirmatory 
performance test, you must postmark a Notification of Compliance 
documenting compliance or noncompliance with the applicable dioxin/
furan emission standard.
    (3) See Secs. 63.7(g), 63.9(h), and 63.1210(d) for additional 
requirements pertaining to the Notification of Compliance (e.g., you 
must include results of performance tests in the Notification of 
Compliance).
    (4) Time extension. You may submit a written request to the 
Administrator for a time extension documenting that, for reasons beyond 
your control, you may not be able to meet the 90-day deadline for 
submitting the Notification of Compliance after completion of testing. 
The Administrator will determine whether a time extension is warranted.
    (k) Failure to submit a timely notification of compliance. (1) If 
you fail to postmark a Notification of Compliance by the specified 
date, you must cease hazardous waste burning immediately.
    (2) Prior to submitting a revised Notification of Compliance as 
provided by paragraph (k)(3) of this section, you may burn hazardous 
waste only for the purpose of pretesting or comprehensive performance 
testing and only for a maximum of 720 hours (renewable at the 
discretion of the Administrator).
    (3) You must submit to the Administrator a Notification of 
Compliance subsequent to a new comprehensive performance test before 
resuming hazardous waste burning.
    (l) Failure of performance test.--(1) Comprehensive performance 
test. (i) If you determine (based on CEM recordings, results of 
analyses of stack samples, or results of CMS performance evaluations) 
that you have exceeded any emission standard during a comprehensive 
performance test for a mode of operation, you must cease hazardous 
waste burning immediately under that mode of operation. You must make 
this determination within 90 days following completion of the 
performance test.
    (ii) If you have failed to demonstrate compliance with the emission 
standards for any mode of operation:
    (A) Prior to submitting a revised Notification of Compliance as 
provided by paragraph (l)(1)(ii)(C) of this section, you may burn 
hazardous waste only for the purpose of pretesting or comprehensive 
performance testing under revised operating conditions, and only for a 
maximum of 720 hours (renewable at the discretion of the 
Administrator), except as provided by paragraph (l)(3) of this section;
    (B) You must conduct a comprehensive performance test under revised 
operating conditions following

[[Page 53054]]

the requirements for performance testing of this section; and
    (C) You must submit to the Administrator a Notification of 
Compliance subsequent to the new comprehensive performance test.
    (2) Confirmatory performance test. If you determine (based on CEM 
recordings, results of analyses of stack samples, or results of CMS 
performance evaluations) that you have failed the dioxin/furan emission 
standard during a confirmatory performance test, you must cease burning 
hazardous waste immediately. You must make this determination within 90 
days following completion of the performance test. To burn hazardous 
waste in the future:
    (i) You must submit to the Administrator for review and approval a 
test plan to conduct a comprehensive performance test to identify 
revised limits on the applicable dioxin/furan operating parameters 
specified in Sec. 63.1209(k);
    (ii) You must submit to the Administrator a Notification of 
Compliance with the dioxin/furan emission standard under the provisions 
of paragraphs (j) and (k) of this section and this paragraph (l). You 
must include in the Notification of Compliance the revised limits on 
the applicable dioxin/furan operating parameters specified in 
Sec. 63.1209(k); and
    (iii) Until the Notification of Compliance is submitted, you must 
not burn hazardous waste except for purposes of pretesting or 
confirmatory performance testing, and for a maximum of 720 hours 
(renewable at the discretion of the Administrator), except as provided 
by paragraph (l)(3) of this section.
    (3) You may petition the Administrator to obtain written approval 
to burn hazardous waste in the interim prior to submitting a 
Notification of Compliance for purposes other than testing or 
pretesting. You must specify operating requirements, including limits 
on operating parameters, that you determine will ensure compliance with 
the emission standards of this subpart based on available information 
including data from the failed performance test. The Administrator will 
review, modify as necessary, and approve if warranted the interim 
operating requirements. An approval of interim operating requirements 
will include a schedule for submitting a Notification of Compliance.
    (m) Waiver of performance test. (1) The waiver provision of this 
paragraph applies in addition to the provisions of Sec. 63.7(h).
    (2) You are not required to conduct performance tests to document 
compliance with the mercury, semivolatile metal, low volatile metal or 
hydrochloric acid/chlorine gas emission standards under the conditions 
specified below. You are deemed to be in compliance with an emission 
standard if the twelve-hour rolling average maximum theoretical 
emission concentration (MTEC) determined as specified below does not 
exceed the emission standard:
    (i) Determine the feedrate of mercury, semivolatile metals, low 
volatile metals, or total chlorine and chloride from all feedstreams;
    (ii) Determine the stack gas flowrate; and
    (iii) Calculate a MTEC for each standard assuming all mercury, 
semivolatile metals, low volatile metals, or total chlorine (organic 
and inorganic) from all feedstreams is emitted;
    (3) To document compliance with this provision, you must:
    (i) Monitor and record the feedrate of mercury, semivolatile 
metals, low volatile metals, and total chlorine and chloride from all 
feedstreams according to Sec. 63.1209(c);
    (ii) Monitor with a CMS and record in the operating record the gas 
flowrate (either directly or by monitoring a surrogate parameter that 
you have correlated to gas flowrate);
    (iii) Continuously calculate and record in the operating record the 
MTEC under the procedures of paragraph (m)(2) of this section; and
    (iv) Interlock the MTEC calculated in paragraph (m)(2)(iii) of this 
section to the AWFCO system to stop hazardous waste burning when the 
MTEC exceeds the emission standard.
    (4) In lieu of the requirement in paragraphs (m)(3)(iii) and (iv) 
of this section, you may:
    (i) Identify in the notification of compliance a minimum gas 
flowrate limit and a maximum feedrate limit of mercury, semivolatile 
metals, low volatile metals, and/or total chlorine and chloride from 
all feedstreams that ensures the MTEC as calculated in paragraph 
(m)(2)(iii) of this section is below the applicable emission standard; 
and
    (ii) Interlock the minimum gas flowrate limit and maximum feedrate 
limit in paragraph (m)(3)(iv) of this section to the AWFCO system to 
stop hazardous waste burning when the gas flowrate or mercury, 
semivolatile metals, low volatile metals, and/or total chlorine and 
chloride feedrate exceeds the limit in paragraph (m)(4)(i) of this 
section.
    (5) When you determine the feedrate of mercury, semivolatile 
metals, low volatile metals, or total chlorine and chloride for 
purposes of this provision, except as provided by paragraph (m)(6) of 
this section, you must assume that the analyte is present at the full 
detection limit when the feedstream analysis determines that the 
analyte is not detected in the feedstream.
    (6) Owners and operators of hazardous waste burning cement kilns 
and lightweight aggregate kilns may assume that mercury is present in 
raw material at half the detection limit when the raw material 
feedstream analysis determines that mercury is not detected.
    (7) You must state in the site-specific test plan that you submit 
for review and approval under paragraph (e) of this section that you 
intend to comply with the provisions of this paragraph. You must 
include in the test plan documentation that any surrogate that is 
proposed for gas flowrate adequately correlates with the gas flowrate.
    (n) Feedrate limits for nondetectable constituents. (1) You must 
establish separate semivolatile metal, low volatile metal, mercury, and 
total chlorine (organic and inorganic), and/or ash feedrate limits for 
each feedstream for which the comprehensive performance test feedstream 
analysis determines that these constituents are not present at 
detectable levels.
    (2) You must define the feedrate limits established under paragraph 
(n)(1) of this section as nondetect at the full detection limit 
achieved during the performance test.
    (3) You will not be deemed to be in violation of the feedrate limit 
established in paragraph (n)(2) of this section when detectable levels 
of the constituent are measured, whether at levels above or below the 
full detection limit achieved during the performance test, provided 
that:
    (i) Your total feedrate for that constituent, including the 
detectable levels in the feedstream which is limited to nondetect 
levels, is below your feedrate limit for that constituent; or
    (ii) Except for ash, your maximum theoretical emission 
concentration (MTEC) for the constituent (i.e., semivolatile metal, low 
volatile metal, mercury, and/or hydrochloric acid/chlorine gas) 
calculated according to paragraph (m) of this section, and considering 
the contribution from all feedstreams including the detectable levels 
in the feedstream which is limited to nondetect levels, is below the 
emission standard in Secs. 63.1203, 63.1204, and 63.1205.

[[Page 53055]]

Sec. 63.1208  What are the test methods?

    (a) References. When required in subpart EEE of this part, the 
following publication is incorporated by reference, ``Test Methods for 
Evaluating Solid Waste, Physical/Chemical Methods,'' EPA Publication 
SW-846 Third Edition (November 1986), as amended by Updates I (July 
1992), II (September 1994), IIA (August 1993), IIB (January 1995), and 
III (December 1996). The Third Edition of SW-846 and Updates I, II, 
IIA, IIB, and III (document number 955-001-00000-1) are available for 
the Superintendent of Document, U.S. Government Printing Office, 
Washington, DC 20402, (202) 512-1800. Copies of the Third Edition and 
its updates are also available from the National Technical Information 
Services (NTIS), 5285 Port Royal Road, Springfield, VA 22161, (703) 
487-4650. Copies may be inspected at the Library, U.S. Environmental 
Protection Agency, 401 M Street, SW, Washington, DC 20460; or at the 
Office of the Federal Register, 800 North Capitol Street, NW, Suite 
700, Washington, DC.
    (b) Test methods. You must use the following test methods to 
determine compliance with the emissions standards of this subpart:
    (1) Dioxins and furans. (i) You must use Method 0023A, Sampling 
Method for Polychlorinated Dibenzo-p-Dioxins and Polychlorinated 
Dibenzofurans emissions from Stationary Sources, EPA Publication SW-
846, as incorporated by reference in paragraph (a) of this section, to 
determine compliance with the emission standard for dioxins and furans;
    (ii) You must sample for a minimum of three hours, and you must 
collect a minimum sample volume of 2.5 dscm;
    (iii) You may assume that nondetects are present at zero 
concentration.
    (2) Mercury. You must use Method 29, provided in appendix A, part 
60 of this chapter, to demonstrate compliance with emission standard 
for mercury.
    (3) Cadmium and lead. You must use Method 29, provided in appendix 
A, part 60 of this chapter, to determine compliance with the emission 
standard for cadmium and lead (combined).
    (4) Arsenic, beryllium, and chromium. You must use Method 29, 
provided in appendix A, part 60 of this chapter, to determine 
compliance with the emission standard for arsenic, beryllium, and 
chromium (combined).
    (5) Hydrochloric acid and chlorine gas. You may use Methods 26A, 
320, or 321 provided in appendix A, part 60 of this chapter, to 
determine compliance with the emission standard for hydrochloric acid 
and chlorine gas (combined). You may use Methods 320 or 321 to make 
major source determinations under Sec. 63.9(b)(2)(v).
    (6) Particulate matter. You must use Methods 5 or 5I, provided in 
appendix A, part 60 of this chapter, to demonstrate compliance with the 
emission standard for particulate matter.
    (7) Other Test Methods. You may use applicable test methods in EPA 
Publication SW-846, as incorporated by reference in paragraph (a) of 
this section, as necessary to demonstrate compliance with requirements 
of this subpart, except as otherwise specified in paragraphs (b)(2)-
(b)(6) of this section.
    (8) Feedstream analytical methods. You may use any reliable 
analytical method to determine feedstream concentrations of metals, 
chlorine, and other constituents. It is your responsibility to ensure 
that the sampling and analysis procedures are unbiased, precise, and 
that the results are representative of the feedstream. For each 
feedstream, you must demonstrate that:
    (i) Each analyte is not present above the reported level at the 80% 
upper confidence limit around the mean; and
    (ii) The analysis could have detected the presence of the 
constituent at or below the reported level at the 80% upper confidence 
limit around the mean. (See Guidance for Data Quality Assessment--
Practical Methods for Data Analysis, EPA QA/G-9, January 1998, EPA/600/
R-96/084).
    (9) Opacity. If you determine compliance with the opacity standard 
under the monitoring requirements of Secs. 63.1209(a)(1)(iv) and 
(a)(1)(v), you must use Method 9, provided in appendix A, part 60 of 
this chapter.


Sec. 63.1209  What are the monitoring requirements?

    (a) Continuous emissions monitoring systems (CEMS) and continuous 
opacity monitoring systems (COMS). (1)(i) You must use a CEMS to 
demonstrate and monitor compliance with the carbon monoxide and 
hydrocarbon standards under this subpart. You must also use an oxygen 
CEMS to continuously correct the carbon monoxide and hydrocarbon levels 
to 7 percent oxygen.
    (ii) For cement kilns, except as provided by paragraphs (a)(1)(iv) 
and (a)(1)(v) of this section, you must use a COMS to demonstrate and 
monitor compliance with the opacity standard under Secs. 63.1204(a)(7) 
and (b)(7) at each point where emissions are vented from these affected 
sources including the bypass stack of a preheater or preheater/
precalciner kiln with dual stacks.
    (A) You must maintain and operate each COMS in accordance with the 
requirements of Sec. 63.8(c) except for the requirements under 
Sec. 63.8(c)(3). The requirements of Sec. 63.1211(d) shall be complied 
with instead of Sec. 63.8(c)(3); and
    (B) Compliance is based on six-minute block average.
    (iii) You must install, calibrate, maintain, and operate a 
particulate matter CEMS to demonstrate and monitor compliance with the 
particulate matter standards under this subpart. However, compliance 
with the requirements in their section to install, calibrate, maintain 
and operate the PM CEMS is not required until such time that the Agency 
promulgates all performance specifications and operational requirements 
applicable to PM CEMS.
    (iv) If you operate a cement kiln subject to the provisions of this 
subpart and use a fabric filter with multiple stacks or an 
electrostatic precipitator with multiple stacks, you may, in lieu of 
installing the COMS required by paragraph (a)(1)(ii) of this section, 
comply with the opacity standard in accordance with the procedures of 
Method 9 to part 60 of this chapter:
    (A) You must conduct the Method 9 test while the affected source is 
operating at the highest load or capacity level reasonably expected to 
occur within the day;
    (B) The duration of the Method 9 test shall be at least 30 minutes 
each day;
    (C) You must use the Method 9 procedures to monitor and record the 
average opacity for each six-minute block period during the test; and
    (D) To remain in compliance, all six-minute block averages must not 
exceed the opacity standard under Secs. 63.1204(a)(7) and (b)(7).
    (v) If you operate a cement kiln subject to the provisions of this 
subpart and use a particulate matter control device that exhausts 
through a monovent, or if the use of a COMS in accordance with the 
installation specification of Performance Specification 1 (PS-1) of 
appendix B to part 60 of this chapter is not feasible, you may, in lieu 
of installing the COMS required by paragraph (a)(1)(ii) of this 
section, comply with the opacity standard in accordance with the 
procedures of Method 9 to part 60 of this chapter:
    (A) You must conduct the Method 9 test while the affected source is 
operating at the highest load or capacity level reasonably expected to 
occur within the day;
    (B) The duration of the Method 9 test shall be at least 30 minutes 
each day;
    (C) You must use the Method 9 procedures to monitor and record the

[[Page 53056]]

average opacity for each six-minute block period during the test; and
    (D) To remain in compliance, all six-minute block averages must not 
exceed the opacity standard under Secs. 63.1204(a)(7) and (b)(7).
    (2) Performance specifications. You must install, calibrate, 
maintain, and continuously operate the CEMS and COMS in compliance with 
the quality assurance procedures provided in the appendix to this 
subpart and Performance Specifications 1 (opacity), 4B (carbon monoxide 
and oxygen), and 8A (hydrocarbons) in appendix B, part 60 of this 
chapter.
    (3) Carbon monoxide readings exceeding the span. (i) Except as 
provided by paragraph (a)(3)(ii) of this section, if a carbon monoxide 
CEMS detects a response that results in a one-minute average at or 
above the 3,000 ppmv span level required by Performance Specification 
4B in appendix B, part 60 of this chapter, the one-minute average must 
be recorded as 10,000 ppmv. The one-minute 10,000 ppmv value must be 
used for calculating the hourly rolling average carbon monoxide level.
    (ii) Carbon monoxide CEMS that use a span value of 10,000 ppmv when 
one-minute carbon monoxide levels are equal to or exceed 3,000 ppmv are 
not subject to paragraph (a)(3)(i) of this section. Carbon monoxide 
CEMS that use a span value of 10,000 are subject to the same CEMS 
performance and equipment specifications when operating in the range of 
3,000 ppmv to 10,000 ppmv that are provided by Performance 
Specification 4B for other carbon monoxide CEMS, except:
    (A) Calibration drift must be less than 300 ppmv; and
    (B) Calibration error must be less than 500 ppmv.
    (4) Hydrocarbon readings exceeding the span. (i) Except as provided 
by paragraph (a)(4)(ii) of this section, if a hydrocarbon CEMS detects 
a response that results in a one-minute average at or above the 100 
ppmv span level required by Performance Specification 8A in appendix B, 
part 60 of this chapter, the one-minute average must be recorded as 500 
ppmv. The one-minute 500 ppmv value must be used for calculating the 
hourly rolling average HC level.
    (ii) Hydrocarbon CEMS that use a span value of 500 ppmv when one-
minute hydrocarbon levels are equal to or exceed 100 ppmv are not 
subject to paragraph (a)(4)(i) of this section. Hydrocarbon CEMS that 
use a span value of 500 ppmv are subject to the same CEMS performance 
and equipment specifications when operating in the range of 100 ppmv to 
500 ppmv that are provided by Performance Specification 8A for other 
hydrocarbon CEMS, except:
    (A) The zero and high-level calibration gas must have a hydrocarbon 
level of between 0 and 100 ppmv, and between 250 and 450 ppmv, 
respectively;
    (B) The strip chart recorder, computer, or digital recorder must be 
capable of recording all readings within the CEM measurement range and 
must have a resolution of 2.5 ppmv;
    (C) The CEMS calibration must not differ by more than 
15 ppmv after each 24-hour period of the seven day test at 
both zero and high levels;
    (D) The calibration error must be no greater than 25 ppmv; and
    (E) The zero level, mid-level, and high level calibration gas used 
to determine calibration error must have a hydrocarbon level of 0-200 
ppmv, 150-200 ppmv, and 350-400 ppmv, respectively.
    (5) Petitions to use CEMS for other standards. You may petition the 
Administrator to use CEMS for compliance monitoring for particulate 
matter, mercury, semivolatile metals, low volatile metals, and 
hydrochloric acid/chlorine gas under Sec. 63.8(f) in lieu of compliance 
with the corresponding operating parameter limits under this section.
    (6) Calculation of rolling averages.--(i) Calculation of rolling 
averages initially. The carbon monoxide and hydrocarbon CEMS must begin 
recording one-minute average values by 12:01 am and hourly rolling 
average values by 1:01 am, when 60 one-minute values will be available 
for calculating the initial hourly rolling average.
    (ii) Calculation of rolling averages upon intermittent operations. 
You must ignore periods of time when one-minute values are not 
available for calculating the hourly rolling average. When one-minute 
values become available again, the first one-minute value is added to 
the previous 59 values to calculate the hourly rolling average.
    (iii) Calculation of rolling averages when the hazardous waste feed 
is cutoff. (A) Except as provided by paragraph (a)(6)(iii)(B) of this 
section, you must continue to monitoring carbon monoxide and 
hydrocarbon when the hazardous waste feed is cutoff if the source is 
operating. You must not resume feeding hazardous waste if the emission 
levels exceed the standard.
    (B) You are not subject to the CEMS requirements of this subpart 
during periods of time you meet the requirements of 
Sec. 63.1206(b)(1)(ii) (compliance with emissions standards for 
nonhazardous waste burning sources when you are not burning hazardous 
waste).
    (7) Operating parameter limits for hydrocarbons. If you elect to 
comply with the carbon monoxide and hydrocarbon emission standards by 
continuously monitoring carbon monoxide with a CEMS, you must 
demonstrate that hydrocarbon emissions during the comprehensive 
performance test do not exceed the hydrocarbon emissions standard. In 
addition, the limits you establish on the destruction and removal 
efficiency (DRE) operating parameters required under paragraph (j) of 
this section also ensure that you maintain compliance with the 
hydrocarbon emission standard. If you do not conduct the hydrocarbon 
demonstration and DRE tests concurrently, you must establish separate 
operating parameter limits under paragraph (j) of this section based on 
each test and the more restrictive of the operating parameter limits 
applies.
    (b) Other continuous monitoring systems (CMS). (1) You must use CMS 
(e.g., thermocouples, pressure transducers, flow meters) to document 
compliance with the applicable operating parameter limits under this 
section.
    (2) Except as specified in paragraphs (b)(2)(i) through (ii) of 
this section, you must install and operate non-CMS in conformance with 
Sec. 63.8(c)(3) that requires you, at a minimum, to comply with the 
manufacturer's written specifications or recommendations for 
installation, operation, and calibration of the system:
    (i) Calibration of thermocouples. The calibration of a thermocouple 
or other temperature sensor must be verified at least once every three 
months; and
    (ii) Accuracy and calibration of weight measurement devices. The 
accuracy of weight measurement devices used to monitor flowrate of a 
feedstream (e.g., activated carbon feedrate, sorbent feedrate, 
nonpumpable waste) must be  1 percent of the weight being 
measured. The calibration of the device must be verified at least once 
every three months.
    (3) CMS must sample the regulated parameter without interruption, 
and evaluate the detector response at least once each 15 seconds, and 
compute and record the average values at least every 60 seconds.
    (4) The span of the non-CEMS CMS detector must not be exceeded. You 
must interlock the span limits into the automatic waste feed cutoff 
system required by Sec. 63.1206(c)(3).
    (5) Calculation of rolling averages.--(i) Calculation of rolling 
averages

[[Page 53057]]

initially. Continuous monitoring systems must begin recording one-
minute average values at 12:01 am on the compliance data and begin 
recording rolling averages when enough one-minute average values are 
available to calculate the required rolling average (e.g., when 60 one-
minute averages are available to calculate an hourly rolling average; 
when 720 one-minute averages are available to calculate a 12-hour 
rolling average).
    (ii) Calculation of rolling averages upon intermittent operations. 
You must ignore periods of time when one-minute values are not 
available for calculating rolling averages. When one-minute values 
become available again, the first one-minute value is added to the 
previous one-minute values to calculate rolling averages.
    (iii) Calculation of rolling averages when the hazardous waste feed 
is cutoff. (A) Except as provided by paragraph (b)(5)(iii)(B) of this 
section, you must continue to monitoring operating parameter limits 
with a CMS when the hazardous waste feed is cutoff if the source is 
operating. You must not resume feeding hazardous waste if an operating 
parameter exceeds its limit.
    (B) You are not subject to the CMS requirements of this subpart 
during periods of time you meet the requirements of 
Sec. 63.1206(b)(1)(ii) (compliance with emissions standards for 
nonhazardous waste burning sources when you are not burning hazardous 
waste).
    (c) Analysis of feedstreams.--(1) General. Prior to feeding the 
material, you must obtain an analysis of each feedstream that is 
sufficient to document compliance with the applicable feedrate limits 
provided by this section.
    (2) Feedstream analysis plan. You must develop and implement a 
feedstream analysis plan and record it in the operating record. The 
plan must specify at a minimum:
    (i) The parameters for which you will analyze each feedstream to 
ensure compliance with the operating parameter limits of this section;
    (ii) Whether you will obtain the analysis by performing sampling 
and analysis or by other methods, such as using analytical information 
obtained from others or using other published or documented data or 
information;
    (iii) How you will use the analysis to document compliance with 
applicable feedrate limits (e.g., if you blend hazardous wastes and 
obtain analyses of the wastes prior to blending but not of the blended, 
as-fired, waste, the plan must describe how you will determine the 
pertinent parameters of the blended waste);
    (iv) The test methods which you will use to obtain the analyses;
    (v) The sampling method which you will use to obtain a 
representative sample of each feedstream to be analyzed using sampling 
methods described in appendix I, part 26, of this chapter, or an 
equivalent method; and
    (vi) The frequency with which you will review or repeat the initial 
analysis of the feedstream to ensure that the analysis is accurate and 
up to date.
    (3) Review and approval of analysis plan. You must submit the 
feedstream analysis plan to the Administrator for review and approval, 
if requested.
    (4) Compliance with feedrate limits. To comply with the applicable 
feedrate limits of this section, you must monitor and record feedrates 
as follows:
    (i) Determine and record the value of the parameter for each 
feedstream by sampling and analysis or other method;
    (ii) Determine and record the mass or volume flowrate of each 
feedstream by a CMS. If you determine flowrate of a feedstream by 
volume, you must determine and record the density of the feedstream by 
sampling and analysis (unless you report the constituent concentration 
in units of weight per unit volume (e.g., mg/l)); and
    (iii) Calculate and record the mass feedrate of the parameter per 
unit time.
    (5) Waiver of monitoring of constituents in certain feedstreams. 
You are not required to monitor levels of metals or chlorine in the 
following feedstreams to document compliance with the feedrate limits 
under this section provided that you document in the comprehensive 
performance test plan the expected levels of the constituent in the 
feedstream and account for those assumed feedrate levels in documenting 
compliance with feedrate limits: natural gas, process air, and 
feedstreams from vapor recovery systems.
    (d) Performance evaluations. (1) The requirements of Secs. 63.8(d) 
(Quality control program) and (e) (Performance evaluation of continuous 
monitoring systems) apply, except that you must conduct performance 
evaluations of components of the CMS under the frequency and procedures 
(for example, submittal of performance evaluation test plan for review 
and approval) applicable to performance tests as provided by 
Sec. 63.1207.
    (2) You must comply with the quality assurance procedures for CEMS 
prescribed in the appendix to this subpart.
    (e) Conduct of monitoring. The provisions of Sec. 63.8(b) apply.
    (f) Operation and maintenance of continuous monitoring systems. The 
provisions of Sec. 63.8(c) apply except:
    (1) Section 63.8(c)(3). The requirements of Sec. 63.1211(d), that 
requires CMSs to be installed, calibrated, and operational on the 
compliance date, shall be complied with instead of section 63.8(c)(3);
    (2) Section 63.8(c)(4)(ii). The performance specifications for 
carbon monoxide, hydrocarbon, and oxygen CEMSs in subpart B, part 60 of 
this chapter that requires detectors to measure the sample 
concentration at least once every 15 seconds for calculating an average 
emission rate once every 60 seconds shall be complied with instead of 
section 63.8(c)(4)(ii); and
    (3) Sections 63.8(c)(4)(i), (c)(5), and (c)(7)(i)(C) pertaining to 
COMS apply only to owners and operators of hazardous waste burning 
cement kilns..
    (g) Alternative monitoring requirements other than continuous 
emissions monitoring systems (CEMS).--(1) Requests to use alternative 
methods. (i) You may submit an application to the Administrator under 
this paragraph for approval of alternative monitoring requirements to 
document compliance with the emission standards of this subpart. For 
requests to use additional CEMS, however, you must use paragraph (a)(5) 
of this section and Sec. 63.8(f).
    (A) The Administrator will not approve averaging periods for 
operating parameter limits longer than specified in this section unless 
you document using data or information that the longer averaging period 
will ensure that emissions do not exceed levels achieved during the 
comprehensive performance test over any increment of time equivalent to 
the time required to conduct three runs of the performance test.
    (B) If the Administrator approves the application to use an 
alternative monitoring requirement, you must continue to use that 
alternative monitoring requirement until you receive approval under 
this paragraph to use another monitoring requirement.
    (ii) You may submit an application to waive an operating parameter 
limit specified in this section based on documentation that neither 
that operating parameter limit nor an alternative operating parameter 
limit is needed to ensure compliance with the emission standards of 
this subpart.
    (iii) You must comply with the following procedures for 
applications submitted under paragraphs (g)(1)(i) and (ii) of this 
section:

[[Page 53058]]

    (A) Timing of the application. You must submit the application to 
the Administrator not later than with the comprehensive performance 
test plan.
    (B) Content of the application. You must include in the 
application:
    (1) Data or information justifying your request for an alternative 
monitoring requirement (or for a waiver of an operating parameter 
limit), such as the technical or economic infeasibility or the 
impracticality of using the required approach;
    (2) A description of the proposed alternative monitoring 
requirement, including the operating parameter to be monitored, the 
monitoring approach/technique (e.g., type of detector, monitoring 
location), the averaging period for the limit, and how the limit is to 
be calculated; and
    (3) Data or information documenting that the alternative monitoring 
requirement would provide equivalent or better assurance of compliance 
with the relevant emission standard, or that it is the monitoring 
requirement that best assures compliance with the standard and that is 
technically and economically practicable.
    (C) Approval of request to use an alternative monitoring 
requirement or waive an operating parameter limit. The Administrator 
will notify you of approval or intention to deny approval of the 
request within 90 calendar days after receipt of the original request 
and within 60 calendar days after receipt of any supplementary 
information that you submit. The Administrator will not approve an 
alternative monitoring request unless the alternative monitoring 
requirement provides equivalent or better assurance of compliance with 
the relevant emission standard, or is the monitoring requirement that 
best assures compliance with the standard and that is technically and 
economically practicable. Before disapproving any request, the 
Administrator will notify you of the Administrator's intention to 
disapprove the request together with:
    (1) Notice of the information and findings on which the intended 
disapproval is based; and
    (2) Notice of opportunity for you to present additional information 
to the Administrator before final action on the request. At the time 
the Administrator notifies you of intention to disapprove the request, 
the Administrator will specify how much time you will have after being 
notified of the intended disapproval to submit the additional 
information.
    (D) Responsibility of owners and operators. You are responsible for 
ensuring that you submit any supplementary and additional information 
supporting your application in a timely manner to enable the 
Administrator to consider your application during review of the 
comprehensive performance test plan. Neither your submittal of an 
application, nor the Administrator's failure to approve or disapprove 
the application, relieves you of the responsibility to comply with the 
provisions of this subpart.
    (2) Administrator's discretion to specify additional or alternative 
requirements. The Administrator may determine on a case-by-case basis 
at any time (e.g., during review of the comprehensive performance test 
plan, during compliance certification review) that you may need to 
limit additional or alternative operating parameters (e.g., opacity in 
addition to or in lieu of operating parameter limits on the particulate 
matter control device) or that alternative approaches to establish 
limits on operating parameters may be necessary to document compliance 
with the emission standards of this subpart.
    (h) Reduction of monitoring data. The provisions of Sec. 63.8(g) 
apply.
    (i) When an operating parameter is applicable to multiple 
standards. Paragraphs (j) through (p) of this section require you to 
establish limits on operating parameters based on comprehensive 
performance testing to ensure you maintain compliance with the emission 
standards of this subpart. For several parameters, you must establish a 
limit for the parameter to ensure compliance with more than one 
emission standard. An example is a limit on minimum combustion chamber 
temperature to ensure compliance with both the DRE standard of 
paragraph (j) of this section and the dioxin/furan standard of 
paragraph (k) of this section. If the performance tests for such 
standards are not performed simultaneously, the most stringent limit 
for a parameter derived from independent performance tests applies.
    (j) DRE. To remain in compliance with the destruction and removal 
efficiency (DRE) standard, you must establish operating limits during 
the comprehensive performance test (or during a previous DRE test under 
provisions of Sec. 63.1206(b)(7)) for the following parameters, unless 
the limits are based on manufacturer specifications, and comply with 
those limits at all times that hazardous waste remains in the 
combustion chamber (i.e., the hazardous waste residence time has not 
transpired since the hazardous waste feed cutoff system was activated):
    (1) Minimum combustion chamber temperature. (i) You must measure 
the temperature of each combustion chamber at a location that best 
represents, as practicable, the bulk gas temperature in the combustion 
zone. You must document the temperature measurement location in the 
test plan you submit under Sec. 63.1207(e);
    (ii) You must establish a minimum hourly rolling average limit as 
the average of the test run averages;
    (2) Maximum flue gas flowrate or production rate. (i) As an 
indicator of gas residence time in the control device, you must 
establish and comply with a limit on the maximum flue gas flowrate, the 
maximum production rate, or another parameter that you document in the 
site-specific test plan as an appropriate surrogate for gas residence 
time, as the average of the maximum hourly rolling averages for each 
run.
    (ii) You must comply with this limit on a hourly rolling average 
basis;
    (3) Maximum hazardous waste feedrate. (i) You must establish limits 
on the maximum pumpable and total (i.e., pumpable and nonpumpable) 
hazardous waste feedrate for each location where hazardous waste is 
fed.
    (ii) You must establish the limits as the average of the maximum 
hourly rolling averages for each run.
    (iii) You must comply with the feedrate limit(s) on a hourly 
rolling average basis;
    (4) Operation of waste firing system. You must specify operating 
parameters and limits to ensure that good operation of each hazardous 
waste firing system is maintained.
    (k) Dioxins and furans. You must comply with the dioxin and furans 
emission standard by establishing and complying with the following 
operating parameter limits. You must base the limits on operations 
during the comprehensive performance test, unless the limits are based 
on manufacturer specifications.
    (1) Gas temperature at the inlet to a dry particulate matter 
control device. (i) For hazardous waste burning incinerators and cement 
kilns, if the combustor is equipped with an electrostatic precipitator, 
baghouse (fabric filter), or other dry emissions control device where 
particulate matter is suspended in contact with combustion gas, you 
must establish a limit on the maximum temperature of the gas at the 
inlet to the device on an hourly rolling average. You must establish 
the hourly rolling average limit as the average of the test run 
averages.
    (ii) For hazardous waste burning lightweight aggregate kilns, you 
must establish a limit on the maximum temperature of the gas at the 
exit of the (last) combustion chamber (or exit of

[[Page 53059]]

any waste heat recovery system) on an hourly rolling average. The limit 
must be established as the average of the test run averages;
    (2) Minimum combustion chamber temperature. (i) You must measure 
the temperature of each combustion chamber at a location that best 
represents, as practicable, the bulk gas temperature in the combustion 
zone. You must document the temperature measurement location in the 
test plan you submit under Secs. 63.1207(e) and (f);
    (ii) You must establish a minimum hourly rolling average limit as 
the average of the test run averages.
    (3) Maximum flue gas flowrate or production rate. (i) As an 
indicator of gas residence time in the control device, you must 
establish and comply with a limit on the maximum flue gas flowrate, the 
maximum production rate, or another parameter that you document in the 
site-specific test plan as an appropriate surrogate for gas residence 
time, as the average of the maximum hourly rolling averages for each 
run.
    (ii) You must comply with this limit on a hourly rolling average 
basis;
    (4) Maximum waste feedrate. (i) You must establish limits on the 
maximum pumpable and total (pumpable and nonpumpable) waste feedrate 
for each location where waste is fed.
    (ii) You must establish the limits as the average of the maximum 
hourly rolling averages for each run.
    (iii) You must comply with the feedrate limit(s) on a hourly 
rolling average basis;
    (5) Particulate matter operating limit. If your combustor is 
equipped with an activated carbon injection or a carbon bed system, you 
must limit particulate matter emissions to the level achieved during 
the comprehensive performance test as prescribed by paragraph (m) of 
this section;
    (6) Activated carbon injection parameter limits. If your combustor 
is equipped with an activated carbon injection system:
    (i) Carbon feedrate. You must establish a limit on minimum carbon 
injection rate on an hourly rolling average calculated as the average 
of the test run averages. If your carbon injection system injects 
carbon at more than one location, you must establish a carbon feedrate 
limit for each location.
    (ii) Carrier fluid. You must establish a limit on minimum carrier 
fluid (gas or liquid) flowrate or pressure drop as an hourly rolling 
average based on the manufacturer's specifications. You must document 
the specifications in the test plan you submit under Secs. 63.1207(e) 
and (f);
    (iii) Carbon specification. (A) You must specify and use the brand 
(i.e., manufacturer) and type of carbon used during the comprehensive 
performance test until a subsequent comprehensive performance test is 
conducted, unless you document in the site-specific performance test 
plan required under Secs. 63.1207(e) and (f) key parameters that affect 
adsorption and establish limits on those parameters based on the carbon 
used in the performance test.
    (B) You may substitute at any time a different brand or type of 
carbon provided that the replacement has equivalent or improved 
properties compared to the carbon used in the performance test and 
conforms to the key sorbent parameters you identify under paragraph 
(k)(6)(iii)(A) of this section. You must include in the operating 
record documentation that the substitute carbon will provide the same 
level of control as the original carbon.
    (7) Carbon bed parameter limits. If your combustor is equipped with 
a carbon bed system:
    (i) Maximum bed age. (A) Except as provided by paragraph 
(k)(7)(i)(C) of this section, the maximum age of the carbon in each 
segment of the bed before you must replace the carbon is the age of the 
bed during the comprehensive performance test.
    (B) You must measure carbon age in terms of the cumulative volume 
of combustion gas flow through carbon since its addition. For beds with 
multiple segments, you must establish the maximum age for each segment.
    (C) For the initial comprehensive performance test, you may base 
the initial limit on maximum age of the carbon in each segment of the 
bed on manufacturer's specifications. If you use manufacturer's 
specifications rather than actual bed age to establish the initial 
limit, you must also recommend in the initial comprehensive performance 
test plan a schedule for subsequent dioxin/furan emissions testing, 
prior to the confirmatory performance test, that you will use to 
document to the Administrator that the initial limit on maximum bed age 
ensures compliance with the dioxin/furan emission standard. If you fail 
to confirm compliance with the emission standard during this testing, 
you must conduct additional testing as necessary to document that a 
revised lower limit on maximum bed age ensures compliance with the 
standard.
    (ii) Carbon specification. (A) You must specify and use the brand 
(i.e., manufacturer) and type of carbon used during the comprehensive 
performance test until a subsequent comprehensive performance test is 
conducted, unless you document in the site-specific performance test 
plan required under Secs. 63.1207(e) and (f) key parameters that affect 
adsorption and establish limits on those parameters based on the carbon 
used in the performance test.
    (B) You may substitute at any time a different brand or type of 
carbon provided that the replacement has equivalent or improved 
properties compared to the carbon used in the performance test. You 
must include in the operating record documentation that the substitute 
carbon will provide an equivalent or improved level of control as the 
original carbon.
    (iii) Maximum temperature. You must measure the temperature of the 
carbon bed at either the bed inlet or exit and you must establish a 
maximum temperature limit on an hourly rolling average as the average 
of the test run averages.
    (8) Catalytic oxidizer parameter limits. If your combustor is 
equipped with a catalytic oxidizer, you must establish limits on the 
following parameters:
    (i) Minimum flue gas temperature at the entrance of the catalyst. 
You must establish a limit on minimum flue gas temperature at the 
entrance of the catalyst on an hourly rolling average as the average of 
the test run averages.
    (ii) Maximum time in-use. You must replace a catalytic oxidizer 
with a new catalytic oxidizer when it has reached the maximum service 
time specified by the manufacturer.
    (iii) Catalyst replacement specifications. When you replace a 
catalyst with a new one, the new catalyst must be equivalent to or 
better than the one used during the previous comprehensive test, as 
measured by:
    (A) Catalytic metal loading for each metal;
    (B) Space time, expressed in the units s-1, the maximum 
rated volumetric flow of combustion gas through the catalyst divided by 
the volume of the catalyst; and
    (C) Substrate construction, including materials of construction, 
washcoat type, and pore density.
    (iv) Maximum flue gas temperature. You must establish a maximum 
flue gas temperature limit at the entrance of the catalyst as an hourly 
rolling average, based on manufacturer's specifications.
    (9) Inhibitor feedrate parameter limits. If you feed a dioxin/furan 
inhibitor into the combustion system, you must establish limits for the 
following parameters:
    (i) Minimum inhibitor feedrate. You must establish a limit on 
minimum inhibitor feedrate on an hourly rolling

[[Page 53060]]

average as the average of the test run averages.
    (ii) Inhibitor specifications. (A) You must specify and use the 
brand (i.e., manufacturer) and type of inhibitor used during the 
comprehensive performance test until a subsequent comprehensive 
performance test is conducted, unless you document in the site-specific 
performance test plan required under Secs. 63.1207(e) and (f) key 
parameters that affect the effectiveness of the inhibitor and establish 
limits on those parameters based on the inhibitor used in the 
performance test.
    (B) You may substitute at any time a different brand or type of 
inhibitor provided that the replacement has equivalent or improved 
properties compared to the inhibitor used in the performance test and 
conforms to the key parameters you identify under paragraph 
(k)(9)(ii)(A) of this section. You must include in the operating record 
documentation that the substitute inhibitor will provide the same level 
of control as the original inhibitor.
    (l) Mercury. You must comply with the mercury emission standard by 
establishing and complying with the following operating parameter 
limits. You must base the limits on operations during the comprehensive 
performance test, unless the limits are based on manufacturer 
specifications.
    (1) Feedrate of total mercury. You must establish a 12-hour rolling 
average limit for the total feedrate of mercury in all feedstreams as 
the average of the hourly rolling averages for each run, unless mercury 
feedrate limits are extrapolated from performance test feedrate levels 
under the following provisions.
    (i) You may request as part of the performance test plan under 
Secs. 63.7(b) and (c) and Secs. 63.1207(e) and (f) to use the mercury 
feedrates and associated emission rates during the comprehensive 
performance test to extrapolate to higher allowable feedrate limits and 
emission rates.
    (ii) The extrapolation methodology will be reviewed and approved, 
as warranted, by the Administrator. The review will consider in 
particular whether:
    (A) Performance test metal feedrates are appropriate (i.e., whether 
feedrates are at least at normal levels; depending on the heterogeneity 
of the waste, whether some level of spiking would be appropriate; and 
whether the physical form and species of spiked material is 
appropriate); and
    (B) Whether the extrapolated feedrates you request are warranted 
considering historical metal feedrate data.
    (iii) The Administrator will review the performance test results in 
making a finding of compliance required by Secs. 63.6(f)(3) and 
63.1206(b)(3) to ensure that you have interpreted emission test results 
properly and that the extrapolation procedure is appropriate for your 
source.
    (2) Wet scrubber. If your combustor is equipped with a wet 
scrubber, you must establish operating parameter limits prescribed by 
paragraph (o)(3) of this section.
    (3) Activated carbon injection. If your combustor is equipped with 
an activated carbon injection system, you must establish operating 
parameter limits prescribed by paragraph (k)(7) of this section.
    (4) Activated carbon bed. If your combustor is equipped with a 
carbon bed system, you must establish operating parameter limits 
prescribed by paragraph (k)(8) of this section.
    (m) Particulate matter. You must comply with the particulate matter 
emission standard by establishing and complying with the following 
operating parameter limits. You must base the limits on operations 
during the comprehensive performance test, unless the limits are based 
on manufacturer specifications.
    (1) Control device operating parameter limits (OPLs). (i) Wet 
scrubbers. For sources equipped with wet scrubbers, including ionizing 
wet scrubbers, high energy wet scrubbers such as venturi, hydrosonic, 
collision, or free jet wet scrubbers, and low energy wet scrubbers such 
as spray towers, packed beds, or tray towers, you must establish limits 
on the following parameters:
    (A) For high energy scrubbers only, minimum pressure drop across 
the wet scrubber on an hourly rolling average, established as the 
average of the test run averages;
    (B) For all wet scrubbers:
    (1) To ensure that the solids content of the scrubber liquid does 
not exceed levels during the performance test, you must either:
    (i) Establish a limit on solids content of the scrubber liquid 
using a CMS or by manual sampling and analysis. If you elect to monitor 
solids content manually, you must sample and analyze the scrubber 
liquid hourly unless you support an alternative monitoring frequency in 
the performance test plan that you submit for review and approval; or
    (ii) Establish a minimum blowdown rate using a CMS and either a 
minimum scrubber tank volume or liquid level using a CMS.
    (2) For maximum solids content monitored with a CMS, you must 
establish a limit on a twelve-hour rolling average as the average of 
the test run averages.
    (3) For maximum solids content measured manually, you must 
establish an hourly limit, as measured at least once per hour, unless 
you support an alternative monitoring frequency in the performance test 
plan that you submit for review and approval. You must establish the 
maximum hourly limit as the average of the manual measurement averages 
for each run.
    (4) For minimum blowdown rate and either a minimum scrubber tank 
volume or liquid level using a CMS, you must establish a limit on an 
hourly rolling average as the average of the test run averages.
    (C) For high energy wet scrubbers only, you must establish limits 
on either the minimum liquid to gas ratio or the minimum scrubber water 
flowrate and maximum flue gas flowrate on an hourly rolling average. If 
you establish limits on maximum flue gas flowrate under this paragraph, 
you need not establish a limit on maximum flue gas flowrate under 
paragraph (m)(2) of this section. You must establish these hourly 
rolling average limits as the average of the test run averages; and
    (D) You must establish limits on minimum power input for ionizing 
wet scrubbers on an hourly rolling average as the average of the test 
run averages.
    (ii) Baghouses. If your combustor is equipped with a baghouse, you 
must establish a limit on minimum pressure drop and maximum pressure 
drop across each baghouse cell based on manufacturer's specifications. 
You must comply with the limit on an hourly rolling average.
    (iii) Electrostatic precipitators. If your combustor is equipped 
with an electrostatic precipitator, you must establish a limit on 
minimum secondary power input (kVa) for each field on an hourly rolling 
average as the average of the test run averages. Secondary power is 
power actually fed to the electrostatic precipitator rather than 
primary power fed to the transformer-rectifier sets.
    (iv) Other particulate matter control devices. For each control 
device that is not a high energy or ionizing wet scrubber, baghouse, or 
electrostatic precipitator but is operated to comply with the 
particulate matter emission standards of this subpart, you must ensure 
that the control device is properly operated and maintained as required 
by Sec. 63.1206(c)(7) and by monitoring the operation of the control 
device as follows:

[[Page 53061]]

    (A) During each comprehensive performance test conducted to 
demonstrate compliance with the particulate matter emissions standard, 
you must establish a range of operating values for the control device 
that is a representative and reliable indicator that the control device 
is operating within the same range of conditions as during the 
performance test. You must establish this range of operating values as 
follows:
    (1) You must select a set of operating parameters appropriate for 
the control device design that you determine to be a representative and 
reliable indicator of the control device performance.
    (2) You must measure and record values for each of the selected 
operating parameters during each test run of the performance test. A 
value for each selected parameter must be recorded using a continuous 
monitor.
    (3) For each selected operating parameter measured in accordance 
with the requirements of paragraph (m)(1)(iv)(A)(1) of this section, 
you must establish a minimum operating parameter limit or a maximum 
operating parameter limit, as appropriate for the parameter, to define 
the operating limits within which the control device can operate and 
still continuously achieve the same operating conditions as during the 
performance test.
    (4) You must prepare written documentation to support the operating 
parameter limits established for the control device and you must 
include this documentation in the performance test plan that you submit 
for review and approval. This documentation must include a description 
for each selected parameter and the operating range and monitoring 
frequency required to ensure the control device is being properly 
operated and maintained.
    (B) You must install, calibrate, operate, and maintain a monitoring 
device equipped with a recorder to measure the values for each 
operating parameter selected in accordance with the requirements of 
paragraph (m)(1)(iv)(A)(1) of this section. You must install, 
calibrate, and maintain the monitoring equipment in accordance with the 
equipment manufacturer's specifications. The recorder must record the 
detector responses at least every 60 seconds, as required in the 
definition of continuous monitor.
    (C) You must regularly inspect the data recorded by the operating 
parameter monitoring system at a sufficient frequency to ensure the 
control device is operating properly. An excursion is determined to 
have occurred any time that the actual value of a selected operating 
parameter is less than the minimum operating limit (or, if applicable, 
greater than the maximum operating limit) established for the parameter 
in accordance with the requirements of paragraph (m)(1)(iv)(A)(3) of 
this section.
    (D) Operating parameters selected in accordance with paragraph 
(m)(1)(iv) of this section may be based on manufacturer specifications 
provided you support the use of manufacturer specifications in the 
performance test plan that you submit for review and approval.
    (2) Maximum flue gas flowrate or production rate. (i) As an 
indicator of gas residence time in the control device, you must 
establish a limit on the maximum flue gas flowrate, the maximum 
production rate, or another parameter that you document in the site-
specific test plan as an appropriate surrogate for gas residence time, 
as the average of the maximum hourly rolling averages for each run.
    (ii) You must comply with this limit on a hourly rolling average 
basis;
    (3) Maximum ash feedrate. Owners and operators of hazardous waste 
incinerators must establish a maximum ash feedrate limit as the average 
of the highest hourly rolling averages for each run.
    (n) Semivolatile metals and low volatility metals. You must comply 
with the semivolatile metal (cadmium and lead) and low volatile metal 
(arsenic, beryllium, and chromium) emission standards by establishing 
and complying with the following operating parameter limits. You must 
base the limits on operations during the comprehensive performance 
test, unless the limits are based on manufacturer specifications.
    (1) Maximum inlet temperature to dry particulate matter air 
pollution control device. You must establish a limit on the maximum 
inlet temperature to the primary dry metals emissions control device 
(e.g., electrostatic precipitator, baghouse) on an hourly rolling 
average basis as the average of the test run averages.
    (2) Maximum feedrate of semivolatile and low volatile metals. (i) 
General. You must establish feedrate limits for semivolatile metals 
(cadmium and lead) and low volatile metals (arsenic, beryllium, and 
chromium) as follows, except as provided by paragraph (n)(2)(ii) of 
this section:
    (A) You must establish a 12-hour rolling average limit for the 
feedrate of cadmium and lead, combined, in all feedstreams as the 
average of the average hourly rolling averages for each run;
    (B) You must establish a 12-hour rolling average limit for the 
feedrate of arsenic, beryllium, and chromium, combined, in all 
feedstreams as the average of the average hourly rolling averages for 
each run; and
    (C) You must establish a 12-hour rolling average limit for the 
feedrate of arsenic, beryllium, and chromium, combined, in all pumpable 
feedstreams as the average of the average hourly rolling averages for 
each run. Dual feedrate limits for both pumpable and total feedstreams 
are not required, however, if you base the total feedrate limit solely 
on the feedrate of pumpable feedstreams.
    (ii) Feedrate extrapolation. (A) You may request as part of the 
performance test plan under Secs. 63.7(b) and (c) and Secs. 63.1207(e) 
and (f) to use the semivolatile metal and low volatile metal feedrates 
and associated emission rates during the comprehensive performance test 
to extrapolate to higher allowable feedrate limits and emission rates.
    (B) The extrapolation methodology will be reviewed and approved, as 
warranted, by the Administrator. The review will consider in particular 
whether:
    (1) Performance test metal feedrates are appropriate (i.e., whether 
feedrates are at least at normal levels; depending on the heterogeneity 
of the waste, whether some level of spiking would be appropriate; and 
whether the physical form and species of spiked material is 
appropriate); and
    (2) Whether the extrapolated feedrates you request are warranted 
considering historical metal feedrate data.
    (C) The Administrator will review the performance test results in 
making a finding of compliance required by Secs. 63.6(f)(3) and 
63.1206(b)(3) to ensure that you have interpreted emission test results 
properly and that the extrapolation procedure is appropriate for your 
source.
    (3) Control device operating parameter limits (OPLs). You must 
establish operating parameter limits on the particulate matter control 
device as specified by paragraph (m)(1) of this section;
    (4) Maximum total chlorine and chloride feedrate. You must 
establish a 12-hour rolling average limit for the feedrate of total 
chlorine and chloride in all feedstreams as the average of the average 
hourly rolling averages for each run.
    (5) Maximum flue gas flowrate or production rate. (i) As an 
indicator of gas residence time in the control device, you must 
establish a limit on the maximum flue gas flowrate, the

[[Page 53062]]

maximum production rate, or another parameter that you document in the 
site-specific test plan as an appropriate surrogate for gas residence 
time, as the average of the maximum hourly rolling averages for each 
run.
    (ii) You must comply with this limit on a hourly rolling average 
basis.
    (o) Hydrochloric acid and chlorine gas. You must comply with the 
hydrogen chloride and chlorine gas emission standard by establishing 
and complying with the following operating parameter limits. You must 
base the limits on operations during the comprehensive performance 
test, unless the limits are based on manufacturer specifications.
    (1) Feedrate of total chlorine and chloride. You must establish a 
12-hour rolling average limit for the total feedrate of chlorine 
(organic and inorganic) in all feedstreams as the average of the 
average hourly rolling averages for each run.
    (2) Maximum flue gas flowrate or production rate. (i) As an 
indicator of gas residence time in the control device, you must 
establish a limit on the maximum flue gas flowrate, the maximum 
production rate, or another parameter that you document in the site-
specific test plan as an appropriate surrogate for gas residence time, 
as the average of the maximum hourly rolling averages for each run.
    (ii) You must comply with this limit on a hourly rolling average 
basis;
    (3) Wet scrubber. If your combustor is equipped with a wet 
scrubber:
    (i) If your source is equipped with a high energy wet scrubber such 
as a venturi, hydrosonic, collision, or free jet wet scrubber, you must 
establish a limit on minimum pressure drop across the wet scrubber on 
an hourly rolling average as the average of the test run averages;
    (ii) If your source is equipped with a low energy wet scrubber such 
as a spray tower, packed bed, or tray tower, you must establish a 
minimum pressure drop across the wet scrubber based on manufacturer's 
specifications. You must comply with the limit on an hourly rolling 
average;
    (iii) If your source is equipped with a low energy wet scrubber, 
you must establish a limit on minimum liquid feed pressure to the wet 
scrubber based on manufacturer's specifications. You must comply with 
the limit on an hourly rolling average;
    (iv) You must establish a limit on minimum pH on an hourly rolling 
average as the average of the test run averages;
    (v) You must establish limits on either the minimum liquid to gas 
ratio or the minimum scrubber water flowrate and maximum flue gas 
flowrate on an hourly rolling average as the average of the test run 
averages. If you establish limits on maximum flue gas flowrate under 
this paragraph, you need not establish a limit on maximum flue gas 
flowrate under paragraph (o)(2) of this section; and
    (vi) You must establish a limit on minimum power input for ionizing 
wet scrubbers on an hourly rolling average as the average of the test 
run averages.
    (4) Dry scrubber. If your combustor is equipped with a dry 
scrubber, you must establish the following operating parameter limits:
    (i) Minimum sorbent feedrate. You must establish a limit on minimum 
sorbent feedrate on an hourly rolling average as the average of the 
test run averages.
    (ii) Minimum carrier fluid flowrate or nozzle pressure drop. You 
must establish a limit on minimum carrier fluid (gas or liquid) 
flowrate or nozzle pressure drop based on manufacturer's 
specifications.
    (iii) Sorbent specifications. (A) You must specify and use the 
brand (i.e., manufacturer) and type of sorbent used during the 
comprehensive performance test until a subsequent comprehensive 
performance test is conducted, unless you document in the site-specific 
performance test plan required under Secs. 63.1207(e) and (f) key 
parameters that affect adsorption and establish limits on those 
parameters based on the sorbent used in the performance test.
    (B) You may substitute at any time a different brand or type of 
sorbent provided that the replacement has equivalent or improved 
properties compared to the sorbent used in the performance test and 
conforms to the key sorbent parameters you identify under paragraph 
(o)(4)(iii)(A) of this section. You must record in the operating record 
documentation that the substitute sorbent will provide the same level 
of control as the original sorbent.
    (p) Maximum combustion chamber pressure. If you comply with the 
requirements for combustion system leaks under Sec. 63.1206(c)(5) by 
maintaining the maximum combustion chamber zone pressure lower than 
ambient pressure, you must monitor the pressure instantaneously and the 
automatic waste feed cutoff system must be engaged when negative 
pressure is not maintained at any time.
    (q) Operating under different modes of operation. If you operate 
under different modes of operation, you must establish operating 
parameter limits for each mode. You must document in the operating 
record when you change a mode of operation and begin complying with the 
operating parameter limits for an alternative mode of operation. You 
must begin calculating rolling averages anew (i.e., without considering 
previous recordings) when you begin complying with the operating 
parameter limits for the alternative mode of operation.

Notification, Reporting and Recordkeeping


Sec. 63.1210  What are the notification requirements?

    (a) Summary of requirements. (1) You must submit the following 
notifications to the Administrator:

------------------------------------------------------------------------
          Reference                           Notification
------------------------------------------------------------------------
63.9(b)......................  Initial notifications that you are
                                subject to Subpart EEE of this Part.
63.1210(b) and (c)...........  Notification of intent to comply.
63.9(d)......................  Notification that you are subject to
                                special compliance requirements.
63.1207(e), 63.9(e)            Notification of performance test and
 63.9(g)(1) and (3).            continuous monitoring system evaluation,
                                including the performance test plan and
                                CMS performance evaluation plan.\1\
63.1210(d), 63.1207(j),        Notification of compliance, including
 63.9(h), 63.10(d)(2),          results of performance tests and
 63.10(e)(2).                   continuous monitoring system performance
                                evaluations.
63.1206(b)(6)................  Notification of changes in design,
                                operation, or maintenance.
63.9(j)......................  Notification and documentation of any
                                change in information already provided
                                under Sec.  63.9.
------------------------------------------------------------------------
\1\ You may also be required on a case-by-case basis to submit a
  feedstream analysis plan under Sec.  63.1209(c)(3).

    (2) You must submit the following notifications to the 
Administrator if you request or elect to comply with alternative 
requirements:

[[Page 53063]]



------------------------------------------------------------------------
                                  Notification, request, petition, or
          Reference                           application
------------------------------------------------------------------------
63.1206(b)(5), 63.1213,        You may request an extension of the
 63.6(i), 63.9(c).              compliance date for up to one year.
63.9(i)......................  You may request an adjustment to time
                                periods or postmark deadlines for
                                submittal and review of required
                                information.
63.1209(g)(1)................  You may request approval of: (1)
                                alternative monitoring methods, except
                                for standards that you must monitor with
                                a continuous emission monitoring system
                                (CEMS) and except for requests to use a
                                CEMS in lieu of operating parameter
                                limits; or (2) a waiver of an operating
                                parameter limit.
63.1209(a)(5), 63.8(f).......  You may request: (1) approval of
                                alternative monitoring methods for
                                compliance with standards that are
                                monitored with a CEMS; and (2) approval
                                to use a CEMS in lieu of operating
                                parameter limits.
63.1204(d)(4)................  Notification that you elect to comply
                                with the emission averaging requirements
                                for cement kilns with in-line raw mills.
63.1204(e)(4)................  Notification that you elect to comply
                                with the emission averaging requirements
                                for preheater or preheater/precalciner
                                kilns with dual stacks.
63.1206(b)(1)(ii)(A).........  Notification that you elect to document
                                compliance with all applicable
                                requirements and standards promulgated
                                under authority of the Clean Air Act,
                                including Sections 112 and 129, in lieu
                                of the requirements of Subpart EEE of
                                this Part when not burning hazardous
                                waste.
63.1206(b)(5)(i)(C)(2).......  You may request to burn hazardous waste
                                for more than 720 hours and for purposes
                                other than testing or pretesting after a
                                making a change in the design or
                                operation that could affect compliance
                                with emission standards and prior to
                                submitting a revised Notification of
                                Compliance.
63.1206(b)(9)(iii)(B)........  If you elect to conduct particulate
                                matter CEMS correlation testing and wish
                                to have federal particulate matter and
                                opacity standards and associated
                                operating limits waived during the
                                testing, you must notify the
                                Administrator by submitting the
                                correlation test plan for review and
                                approval.
63.1206(b)(10)...............  Owners and operators of lightweight
                                aggregate kilns may request approval of
                                alternative emission standards for
                                mercury, semivolatile metal, low
                                volatile metal, and hydrochloric acid/
                                chlorine gas under certain conditions.
63.1206(b)(11)...............  Owners and operators of cement kilns may
                                request approval of alternative emission
                                standards for mercury, semivolatile
                                metal, low volatile metal, and
                                hydrochloric acid/chlorine gas under
                                certain conditions.
63.1206(b)(14)...............  Owners and operators of incinerators may
                                comply with an alternative particulate
                                matter standard of 68 mg/dscm, corrected
                                to 7% oxygen, under a petition
                                documenting de minimis metals levels in
                                feedstreams.
63.1207(c)(2)................  You may request to base initial
                                compliance on data in lieu of a
                                comprehensive performance test.
63.1207(d)(3)................  You may request more than 60 days to
                                complete a performance test if
                                additional time is needed for reasons
                                beyond your control.
63.1207(i)...................  You may request up to a one-year time
                                extension for conducting a performance
                                test (other than the initial
                                comprehensive performance test) to
                                consolidate testing with other state or
                                federally-required testing.
63.1207(j)(4)................  You may request more than 90 days to
                                submit a Notification of Compliance
                                after completing a performance test if
                                additional time is needed for reasons
                                beyond your control.
63.1207(l)(3)................  After failure of a performance test, you
                                may request to burn hazardous waste for
                                more than 720 hours and for purposes
                                other than testing or pretesting.
63.1209(l)(1)................  You may request to extrapolate mercury
                                feedrate limits.
63.1209(n)(2)(ii)............  You may request to extrapolate
                                semivolatile and low volatile metal
                                feedrate limits.
63.10(e)(3)(ii)..............  You may request to reduce the frequency
                                of excess emissions and CMS performance
                                reports.
63.10(f).....................  You may request to waive recordkeeping or
                                reporting requirements.
63.1211(e)...................  You may request to use data compression
                                techniques to record data on a less
                                frequent basis than required by Sec.
                                63.1209.
------------------------------------------------------------------------

    (b) Notification of intent to comply (NIC). (1) You must prepare a 
Notification of Intent to Comply that includes the following 
information:
    (i) General information:
    (A) The name and address of the owner/operator and the source;
    (B) Whether the source is a major or an area source;
    (C) Waste minimization and emission control technique(s) being 
considered;
    (D) Emission monitoring technique(s) you are considering;
    (E) Waste minimization and emission control technique(s) 
effectiveness;
    (F) A description of the evaluation criteria used or to be used to 
select waste minimization and/or emission control technique(s); and
    (G) A statement that you intend to comply with the emission 
standards of this subpart.
    (ii) Information on key activities and estimated dates for these 
activities that will bring the source into compliance with emission 
control requirements of this subpart. The submission of key activities 
and dates is not intended to be static and you may revise them during 
the period the NIC is in effect. You must submit revisions to the 
Administrator and make them available to the public. You must include 
the following key activities and dates:
    (A) The dates for beginning and completion of engineering studies 
to evaluate emission control systems or process changes for emissions;
    (B) The date by which you will award contracts for emission control 
systems or process changes for emission control, or the date by which 
you will issue orders for the purchase of component parts to accomplish 
emission control or process changes;
    (C) The date by which you will submit construction applications;
    (D) The date by which you will initiate on-site construction, 
installation of emission control equipment, or process change;
    (E) The date by which you will complete on-site construction, 
installation of emission control equipment, or process change; and
    (F) The date by which you will achieve final compliance. The 
individual dates and milestones listed in paragraphs (b)(1)(ii)(A) 
through (F) of this section as part of the NIC are not requirements and 
therefore are not enforceable deadlines; the requirements of paragraphs 
(b)(1)(ii)(A) through (F) of this section must be included as part of 
the NIC only to inform the public of

[[Page 53064]]

your intention to comply with the emission standards of this subpart.
    (iii) A summary of the public meeting required under paragraph (c) 
of this section.
    (iv) If you do not intent to comply, but will not stop burning 
hazardous waste by October 1, 2001 a certification that:
    (A) You will stop burning hazardous waste on or before September 
30, 2002; and
    (B) It is necessary to combust the hazardous waste from another on-
site source, during the year prior to September 30, 2002 because that 
other source is:
    (1) Installing equipment to come into compliance with the emission 
standards of this subpart; or
    (2) Installing source reduction modifications to eliminate the need 
for further combustion of wastes.
    (2) You must make a draft of the NIC available for public review no 
later than 30 days prior to the public meeting required under paragraph 
(c)(1) of this section.
    (3) You must submit the final NIC to the Administrator no later 
than October 2, 2000.
    (c) NIC public meeting and notice. (1) Prior to the submission of 
the NIC to the permitting agency, and no later than July 31, 2000, you 
must hold at least one informal meeting with the public to discuss 
anticipated activities described in the draft NIC for achieving 
compliance with the emission standards of this subpart. You must post a 
sign-in sheet or otherwise provide a voluntary opportunity for 
attendees to provide their names and addresses.
    (2) You must submit a summary of the meeting, along with the list 
of attendees and their addresses developed under paragraph (b)(1) of 
this section, and copies of any written comments or materials submitted 
at the meeting, to the Administrator as part of the final NIC, in 
accordance with paragraph (b)(1)(iii) of this section.
    (3) You must provide public notice of the NIC meeting at least 30 
days prior to the meeting. You must provide public notice in all of the 
following forms:
    (i) Newspaper advertisement. You must publish a notice in a 
newspaper of general circulation in the county or equivalent 
jurisdiction of your facility. In addition, you must publish the notice 
in newspapers of general circulation in adjacent counties or equivalent 
jurisdiction where such publication would be necessary to inform the 
affected public. You must publish the notice as a display 
advertisement.
    (ii) Visible and accessible sign. You must post a notice on a 
clearly marked sign at or near the source. If you place the sign on the 
site of the hazardous waste combustor, the sign must be large enough to 
be readable from the nearest spot where the public would pass by the 
site.
    (iii) Broadcast media announcement. You must broadcast a notice at 
least once on at least one local radio station or television station.
    (iv) Notice to the facility mailing list. You must provide a copy 
of the notice to the facility mailing list in accordance with 
Sec. 124.10(c)(1)(ix) of this chapter.
    (4) You must include the following in the notices required under 
paragraph (c)(3) of this section:
    (i) The date, time, and location of the meeting;
    (ii) A brief description of the purpose of the meeting;
    (iii) A brief description of the source and proposed operations, 
including the address or a map (e.g., a sketched or copied street map) 
of the source location;
    (iv) A statement encouraging people to contact the source at least 
72 hours before the meeting if they need special access to participate 
in the meeting;
    (v) A statement describing how the draft NIC can be obtained; and
    (vi) The name, address, and telephone number of a contact person 
for the NIC.
    (d) Notification of compliance. (1) The Notification of Compliance 
status requirements of Sec. 63.9(h) apply, except that:
    (i) The notification is a Notification of Compliance, rather than 
compliance status;
    (ii) The notification is required for the initial comprehensive 
performance test and each subsequent comprehensive and confirmatory 
performance test; and
    (iii) You must postmark the notification before the close of 
business on the 90th day following completion of relevant compliance 
demonstration activity specified in this subpart rather than the 60th 
day as required by Sec. 63.9(h)(2)(ii).
    (2) Upon postmark of the Notification of Compliance, the operating 
parameter limits identified in the Notification of Compliance, as 
applicable, shall be complied with, the limits identified in the 
Documentation of Compliance or a previous Notification of Compliance 
are no longer applicable.
    (3) The Notification of Compliance requirements of Sec. 63.1207(j) 
also apply.


Sec. 63.1211  What are the recordkeeping and reporting requirements?

    (a) Summary of reporting requirements. You must submit the 
following reports to the Administrator:

------------------------------------------------------------------------
          Reference                              Report
------------------------------------------------------------------------
63.1211(b)...................  Compliance progress report associated and
                                submitted with the notification of
                                intent to comply.
63.10(d)(4)..................  Compliance progress reports, if required
                                as a condition of an extension of the
                                compliance date granted under Sec.
                                63.6(i).
63.1206(c)(3)(vi)............  Excessive exceedances reports.
63.1206(c)(4)(iv)............  Emergency safety vent opening reports.
63.10(d)(5)(i)...............  Periodic startup, shutdown, and
                                malfunction reports.
63.10(d)(5)(ii)..............  Immediate startup, shutdown, and
                                malfunction reports.
63.10(e)(3)..................  Excessive emissions and continuous
                                monitoring system performance report and
                                summary report.
------------------------------------------------------------------------

    (b) Compliance progress reports associated with the notification of 
intent to comply. (1) General. Not later than October 1, 2001, you must 
comply with the following, unless you comply with paragraph (b)(2)(ii) 
of this section:
    (i) Complete engineering design for any physical modifications to 
the source needed to comply with the emission standards of this 
subpart;
    (ii) Submit applicable construction applications to the 
Administrator; and
    (iii) Enter into a binding contractual commitment to purchase, 
fabricate, and install any equipment, devices, and ancillary structures 
needed to comply with the emission standards of this subpart.
    (2) Demonstration. (i) You must submit to the Administrator a 
progress report on or before October 1, 2001 which contains information 
demonstrating that you have met the requirements of paragraph (b)(1) of 
this section. This information will be used by the Administrator to 
determine if you have made adequate progress towards compliance with 
the emission standards of this subpart.

[[Page 53065]]

    (ii) If you intend to comply with the emission standards of this 
subpart, but can do so without undertaking any of the activities 
described in paragraph (b)(1) of this section, you must submit 
documentation either:
    (A) Demonstrating that you, at the time of the progress report, are 
in compliance with the emission standards and operating requirements; 
or
    (B) Specifying the steps that you will take to comply, without 
undertaking any of the activities listed in paragraphs (b)(1)(i) 
through (b)(1)(iii) of this section.
    (iii) If you do not comply with paragraph (b)(1) or (b)(2)(ii) of 
this section, you must stop burning hazardous waste on or before 
October 1, 2001.
    (3) Schedule. (i) You must include in the progress report a 
detailed schedule that lists key dates for all projects that will bring 
the source into compliance with the emission standards and operating 
requirements of this subpart (i.e., key dates for the activities 
required under paragraphs (b)(1)(i) through (iii) of this section). 
Dates must cover the time frame from the progress report through the 
compliance date of the emission standards and operating requirements of 
this subpart.
    (ii) The schedule must contain the following dates:
    (A) Bid and award dates for construction contracts and equipment 
supply contractors;
    (B) Milestones such as ground breaking, completion of drawings and 
specifications, equipment deliveries, intermediate construction 
completions, and testing;
    (C) The dates on which applications were submitted for or obtained 
operating and construction permits or licenses;
    (D) The dates by which approvals of any permits or licenses are 
anticipated; and
    (E) The projected date by which you will comply with the emission 
standards and operating requirements of this subpart.
    (4) Notice of intent to comply. You must include a statement in the 
progress report that you intend or do not intend to comply with the 
emission standards and operating requirements of this subpart.
    (5) Sources that do not intend to comply. (i) If you indicated in 
your NIC your intent not to comply with the emission standards and 
operating requirements of this subpart and stop burning hazardous waste 
prior to submitting a progress report, or if you meet the requirements 
of Sec. 63.1206(a)(2), you are exempt from the requirements of 
paragraphs (b)(2) and (b)(3) of this section. However, you must include 
in your progress report the date on which you stopped burning hazardous 
waste and the date(s) you submitted RCRA closure documents.
    (ii) If you signify in the progress report, submitted not later 
than October 1, 2001, your intention not to comply with the emission 
standards and operating requirements of this subpart, you must stop 
burning hazardous waste on or before October 1, 2001.
    (c) Summary of recordkeeping requirements. You must retain the 
following in the operating record:

------------------------------------------------------------------------
          Reference                  Document, data, or information
------------------------------------------------------------------------
63.1201(a), 63.10(b) and (c).  General. Information required to document
                                and maintain compliance with the
                                regulations of Subpart EEE, including
                                data recorded by continuous monitoring
                                systems (CMS), and copies of all
                                notifications, reports, plans, and other
                                documents submitted to the
                                Administrator.
63.1211(d)...................  Documentation of compliance.
63.1206(c)(3)(vii)...........  Documentation and results of the
                                automatic waste feed cutoff operability
                                testing.
63.1209(c)(2)................  Feedstream analysis plan.
63.1204(d)(3)................  Documentation of compliance with the
                                emission averaging requirements for
                                cement kilns with in-line raw mills.
63.1204(e)(3)................  Documentation of compliance with the
                                emission averaging requirements for
                                preheater or preheater/precalciner kilns
                                with dual stacks.
63.1206(b)(1)(ii)(B).........  If you elect to comply with all
                                applicable requirements and standards
                                promulgated under authority of the Clean
                                Air Act, including Sections 112 and 129,
                                in lieu of the requirements of Subpart
                                EEE when not burning hazardous waste,
                                you must document in the operating
                                record that you are in compliance with
                                those requirements.
63.1206(c)(2)................  Startup, shutdown, and malfunction plan.
63.1206(c)(3)(v).............  Corrective measures for any automatic
                                waste feed cutoff that results in an
                                exceedance of an emission standard or
                                operating parameter limit.
63.1206(c)(4)(ii)............  Emergency safety vent operating plan.
63.1206(c)(4)(iii)...........  Corrective measures for any emergency
                                safety vent opening.
63.1206(c)(6)................  Operator training and certification
                                program.
63.1206(c)(7)................  Ramp down procedures for waste feed
                                cutoffs.
63.1209(k)(6)(iii),            Documentation that a substitute activated
 63.1209(k)(7)(ii),             carbon, dioxin/furan formation reaction
 63.1209(k)(9)(ii),             inhibitor, or dry scrubber sorbent will
 63.1209(o)(4)(iii).            provide the same level of control as the
                                original material.
------------------------------------------------------------------------

    (d) Documentation of compliance. (1) By the compliance date, you 
must develop and include in the operating record a Documentation of 
Compliance.
    (2) The Documentation of Compliance must identify the applicable 
emission standards under this subpart and the limits on the operating 
parameters under Sec. 63.1209 that will ensure compliance with those 
emission standards.
    (3) You must include a signed and dated certification in the 
Documentation of Compliance that:
    (i) Required CEMs and CMS are installed, calibrated, and 
continuously operating in compliance with the requirements of this 
subpart; and
    (ii) Based on an engineering evaluation prepared under your 
direction or supervision in accordance with a system designed to ensure 
that qualified personnel properly gathered and evaluated the 
information and supporting documentation, and considering at a minimum 
the design, operation, and maintenance characteristics of the combustor 
and emissions control equipment, the types, quantities, and 
characteristics of feedstreams, and available emissions data:
    (A) You are in compliance with the emission standards of this 
subpart; and
    (B) The limits on the operating parameters under Sec. 63.1209 
ensure compliance with the emission standards of this subpart.
    (4) You must comply with the emission standards and operating 
parameter limits specified in the Documentation of Compliance.

[[Page 53066]]

    (e) Data compression. You may submit a written request to the 
Administrator for approval to use data compression techniques to record 
data from CMS, including CEMS, on a frequency less than that required 
by Sec. 63.1209. You must submit the request for review and approval as 
part of the comprehensive performance test plan.
    (1) You must record a data value at least once each ten minutes.
    (2) For each CEMS or operating parameter for which you request to 
use data compression techniques, you must recommend:
    (i) A fluctuation limit that defines the maximum permissible 
deviation of a new data value from a previously generated value without 
requiring you to revert to recording each one-minute value.
    (A) If you exceed a fluctuation limit, you must record each one-
minute value for a period of time not less than ten minutes.
    (B) If neither the fluctuation limit nor the data compression limit 
are exceeded during that period of time, you may reinitiate recording 
data values on a frequency of at least once each ten minutes; and
    (ii) A data compression limit defined as the closest level to an 
operating parameter limit or emission standard at which reduced data 
recording is allowed.
    (A) Within this level and the operating parameter limit or emission 
standard, you must record each one-minute average.
    (B) The data compression limit should reflect a level at which you 
are unlikely to exceed the specific operating parameter limit or 
emission standard, considering its averaging period, with the addition 
of a new one-minute average.


Sec. 63.1212  What are the other requirements pertaining to the NIC and 
associated progress reports?

    (a) Certification of intent to comply. (1) The Notice of Intent to 
Comply (NIC) and Progress Report must contain the following 
certification signed and dated by an authorized representative of the 
source: I certify under penalty of law that I have personally examined 
and am familiar with the information submitted in this document and all 
attachments and that, based on my inquiry of those individuals 
immediately responsible for obtaining the information, I believe that 
the information is true, accurate, and complete. I am aware that there 
are significant penalties for submitting false information, including 
the possibility of fine and imprisonment.
    (2) An authorized representative should be a responsible corporate 
officer (for a corporation), a general partner (for a partnership), the 
proprietor (of a sole proprietorship), or a principal executive officer 
or ranking elected official (for a municipality, State, Federal, or 
other public agency).
    (b) Sources that begin burning hazardous waste after September 30, 
1999. (1) If you begin to burn hazardous waste after September 30, 1999 
but prior to June 30, 2000 you must comply with the requirements of 
Secs. 63.1206(a)(2), 63.1210(b) and (c), 63.1211(b), and paragraph (a) 
of this section, and associated time frames for public meetings and 
document submittals.
    (2) If you intend to begin burning hazardous waste after June 30, 
2000, you must comply with the requirements of Secs. 63.1206(a)(2), 
63.1210(b) and (c), 63.1211(b), and paragraph (a) of this section prior 
to burning hazardous waste. In addition:
    (i) You must make a draft NIC available to the public, notice the 
public meeting, conduct a public meeting, and submit a final NIC prior 
to burning hazardous waste; and
    (ii) You must submit your progress report at the time you submit 
your final NIC.

Other


Sec. 63.1213  How can the compliance date be extended to install 
pollution prevention or waste minimization controls?

    (a) Applicability. You may request from the Administrator or State 
with an approved Title V program an extension of the compliance data of 
up to one year. An extension may be granted if you can reasonably 
document that the installation of pollution prevention or waste 
minimization measures will significantly reduce the amount and/or 
toxicity of hazardous wastes entering the feedstream(s) of the 
hazardous waste combustor(s), and that you could not install the 
necessary control measures and comply with the emission standards and 
operating requirements of this subpart within three years after their 
effective date.
    (b) Requirements for requesting an extension. (1) You must make 
your requests for a (up to) one-year extension in writing, and it must 
be received not later than 12 months before the compliance date. The 
request must contain the following information:
    (i) A description of pollution prevention or waste minimization 
controls that, when installed, will significantly reduce the amount 
and/or toxicity of hazardous wastes entering the feedstream(s) of the 
hazardous waste combustor(s). Pollution prevention or waste 
minimization measures may include: equipment or technology 
modifications, reformulation or redesign of products, substitution of 
raw materials, improvements in work practices, maintenance, training, 
inventory control, or recycling practices conducted as defined in 
Sec. 261.1(c) of this chapter;
    (ii) A description of other pollution controls to be installed that 
are necessary to comply with the emission standards and operating 
requirements;
    (iii) A reduction goal or estimate of the annual reductions in 
quantity and/or toxicity of hazardous waste(s) entering combustion 
feedstream(s) that you will achieve by installing the proposed 
pollution prevention or waste minimization measures;
    (iv) A comparison of reductions in the amounts and/or toxicity of 
hazardous wastes combusted after installation of pollution prevention 
or waste minimization measures to the amounts and/or toxicity of 
hazardous wastes combusted prior to the installation of these measures. 
If the difference is less than a fifteen percent reduction, include a 
comparison to pollution prevention and waste minimization reductions 
recorded during the previous five years;
    (v) Reasonable documentation that installation of the pollution 
prevention or waste minimization changes will not result in a net 
increase (except for documented increases in production) of hazardous 
constituents released to the environment through other emissions, 
wastes or effluents;
    (vi) Reasonable documentation that the design and installation of 
waste minimization and other measures that are necessary for compliance 
with the emission standards and operating requirements of this subpart 
cannot otherwise be installed within the three year compliance period, 
and
    (vii) The information required in Sec. 63.6(i)(6)(i)(B) through 
(D).
    (2) You may enclose documentation prepared under an existing State-
required pollution prevention program that contains the information 
prescribed in paragraph (b) of this section with a request for 
extension in lieu of complying with the time extension requirements of 
that paragraph.
    (c) Approval of request for extension of compliance date. Based on 
the information provided in any request made under paragraph (a) of 
this section, the Administrator or State with an approved title V 
program may grant an extension of the compliance date of this subpart. 
The extension will be in writing in accordance with 
Secs. 63.6(i)(10)(i) through 63.6(i)(10)(v)(A).

[[Page 53067]]



                      Table 1 to Subpart EEE.--General Provisions Applicable to Subpart EEE
----------------------------------------------------------------------------------------------------------------
              Reference                Applies to Subparts EEE                     Explanation
----------------------------------------------------------------------------------------------------------------
63.1................................  Yes.....................
63.2................................  Yes.....................
63.3................................  Yes.....................
63.4................................  Yes.....................
63.5................................  Yes.....................
63.6(a), (b), (c), and (d)..........  Yes.....................
63.6(e).............................  Yes.....................  Except Sec.  63.1206(b)(1) and (c)(2)(ii)
                                                                 require compliance with the emission standards
                                                                 during startup, shutdown, and malfunction if
                                                                 hazardous waste is burned or remains in the
                                                                 combustion chamber during those periods of
                                                                 operation.
63.6(f)(1)..........................  Yes.....................  Same exception that applies to Sec.  63.6(e).
63.6(f)(2)..........................  Yes.....................  Except that the performance test requirements of
                                                                 Sec.  63.1207 apply instead of Sec.
                                                                 63.6(f)(2)(iii)(B).
63.6(f)(3)..........................  Yes.....................
63.6(g).............................  Yes.....................
63.6(h).............................  Yes.....................  Except only cement kilns are subject to an
                                                                 opacity standard, and Sec.  63.1206(b)(1)
                                                                 requires compliance with the opacity standard
                                                                 at all times that hazardous waste is in the
                                                                 combustion chamber.
63.6(i).............................  Yes.....................  Section Sec.  63.1213 specifies that the
                                                                 compliance date may also be extended for
                                                                 inability to install necessary emission control
                                                                 equipment by the compliance date because of
                                                                 implementation of pollution prevention or waste
                                                                 minimization controls.
63.6(j).............................  Yes.....................
63.7(a).............................  Yes.....................
63.7(b).............................  Yes.....................  Except Sec.  63.1207(e) requires you to submit
                                                                 the site-specific test plan for approval at
                                                                 least one year before the comprehensive
                                                                 performance test is scheduled to begin.
63.7(c).............................  Yes.....................  Except Sec.  63.1207(e) requires you to submit
                                                                 the site-specific test plan (including the
                                                                 quality assurance provisions under Sec.
                                                                 63.7(c)) for approval at least one year before
                                                                 the comprehensive performance test is scheduled
                                                                 to begin.
63.7(d).............................  Yes.....................
63.7(e).............................  Yes.....................  Except: (1) Sec.  63.1207 prescribes operations
                                                                 during performance testing; (2) Sec.  63.1209
                                                                 specifies operating limits that will be
                                                                 established during performance testing (such
                                                                 that testing is likely to be representative of
                                                                 the extreme range of normal performance); and
                                                                 (3) Secs.  63.1206(b)(1) and (c)(2) require
                                                                 compliance with the emission standards during
                                                                 startup, shutdown, and malfunction if hazardous
                                                                 waste is burned or remains in the combustion
                                                                 chamber during those periods of operation.
63.7(f).............................  Yes.....................
63.7(g).............................  Yes.....................  Except that Sec.  63.1207(j) requiring the
                                                                 results of the performance test (and the
                                                                 notification of compliance) to be submitted
                                                                 within 90 days of completing the test, unless
                                                                 the Administrator grants a time extension,
                                                                 applies instead of Sec.  63.7(g)(1).
63.7(h).............................  Yes.....................  Except Sec.  63.1207(c)(2) allows data in lieu
                                                                 of the initial comprehensive performance test,
                                                                 and Sec.  63.1207(m) provides a waiver of
                                                                 certain performance tests. You must submit
                                                                 requests for these waivers with the site-
                                                                 specific test plan.
63.8(a) and (b).....................  Yes.....................
63.8(c).............................  Yes.....................  Except: (1) Sec.  63.1211(d) that requires CMS
                                                                 to be installed, calibrated, and operational on
                                                                 the compliance date applies instead of Sec.
                                                                 63.8(c)(3); (2) the performance specifications
                                                                 for CO, HC, and O2 CEMS in subpart B, part 60,
                                                                 of this chapter requiring that the detectors
                                                                 measure the sample concentration at least once
                                                                 every 15 seconds for calculating an average
                                                                 emission level once every 60 seconds apply
                                                                 instead of Sec.  63.8(c)(4)(ii); and (3) Secs.
                                                                 63.8(c)(4)(i), (c)(5), and (c)(7)(i)(C)
                                                                 pertaining to COMS apply only to cement kilns.
63.8(d).............................  Yes.....................
63.8(e).............................  Yes.....................  Except Sec.  63.1207(e) requiring sources to
                                                                 submit the site-specific comprehensive
                                                                 performance test plan and the CMS performance
                                                                 evaluation plan for approval at least one year
                                                                 prior to the planned test date applies instead
                                                                 of Secs.  63.8(e)(2) and (3)(iii).
63.8(f).............................  Yes.....................
63.8(g).............................  Yes.....................  Except Sec.  63.8(g)(2) regarding data reduction
                                                                 for COMS applies only to cement kilns.
63.9(a).............................  Yes.....................
63.9(b).............................  Yes.....................  Note: Section 63.9(b)(1)(ii) pertains to
                                                                 notification requirements for area sources that
                                                                 become a major source, and Sec.  93.9(b)(2)(v)
                                                                 requires a major source determination. Although
                                                                 area sources are subject to all provisions of
                                                                 this subpart (Subpart EEE), these sections
                                                                 nonetheless apply because the major source
                                                                 determination may affect the applicability of
                                                                 part 63 standards or title V permit
                                                                 requirements to other sources (i.e., other than
                                                                 a hazardous waste combustor) of hazardous air
                                                                 pollutants at the facility.
63.9(c) and (d).....................  Yes.....................
63.9(e).............................  Yes.....................  Except Sec.  63.1207(e) which requires the
                                                                 comprehensive performance test plan to be
                                                                 submitted for approval one year prior to the
                                                                 planned performance test date applies instead
                                                                 of Sec.  63.9(e).
63.9(f).............................  No......................
63.9(g).............................  Yes.....................  Except Sec.  63.9(g)(2) pertaining to COMS does
                                                                 not apply.
63.9(h).............................  Yes.....................  Except Sec.  63.1207(j) requiring the
                                                                 notification of compliance to be submitted
                                                                 within 90 days of completing a performance test
                                                                 unless the Administrator grants a time
                                                                 extension applies instead of Sec.
                                                                 63.9(h)(2)(ii). Note: Even though area sources
                                                                 are subject to this subpart, the major source
                                                                 determination required by Sec.
                                                                 63.9(h)(2)(i)(E) is applicable to hazardous
                                                                 waste combustors for the reasons discussed
                                                                 above.
63.9(i) and (j).....................  Yes.....................

[[Page 53068]]

 
63.10...............................  Yes.....................  Except reports of performance test results
                                                                 required under Sec.  63.10(d)(2) may be
                                                                 submitted up to 90 days after completion of the
                                                                 test.
63.11...............................  No......................
63.12-63.15.........................  Yes.....................
----------------------------------------------------------------------------------------------------------------

Appendix to Subpart EEE of Part 63--Quality Assurance Procedures 
for Continuous Emissions Monitors Used for Hazardous Waste 
Combustors

1. Applicability and Principle

    1.1  Applicability. a. These quality assurance requirements are 
used to evaluate the effectiveness of quality control (QC) and 
quality assurance (QA) procedures and the quality of data produced 
by continuous emission monitoring systems (CEMS) that are used for 
determining compliance with the emission standards on a continuous 
basis as specified in the applicable regulation. The QA procedures 
specified by these requirements represent the minimum requirements 
necessary for the control and assessment of the quality of CEMS data 
used to demonstrate compliance with the emission standards provided 
under subpart EEE of this part 63. Owners and operators must meet 
these minimum requirements and are encouraged to develop and 
implement a more extensive QA program. These requirements superede 
those found in part 60, appendix F of this chapter. Appendix F does 
not apply to hazardous waste-burning devices.
    b. Data collected as a result of the required QA and QC measures 
are to be recorded in the operating record. In addition, data 
collected as a result of CEMS performance evaluations required by 
Section 5 in conjunction with an emissions performance test are to 
be submitted to the Administrator as provided by Sec. 63.8(e)(5). 
These data are to be used by both the Agency and the CEMS operator 
in assessing the effectiveness of the CEMS QA and QC procedures in 
the maintenance of acceptable CEMS operation and valid emission 
data.
    1.2  Principle. The QA procedures consist of two distinct and 
equally important functions. One function is the assessment of the 
quality of the CEMS data by estimating accuracy. The other function 
is the control and improvement of the quality of the CEMS data by 
implementing QC policies and corrective actions. These two functions 
form a control loop. When the assessment function indicates that the 
data quality is inadequate, the source must immediately stop burning 
hazardous waste. The CEM data control effort must be increased until 
the data quality is acceptable before hazardous waste burning can 
resume.
    a. In order to provide uniformity in the assessment and 
reporting of data quality, this procedure explicitly specifies the 
assessment methods for response drift and accuracy. The methods are 
based on procedures included in the applicable performance 
specifications provided in appendix B to part 60 of this chapter. 
These procedures also require the analysis of the EPA audit samples 
concurrent with certain reference method (RM) analyses as specified 
in the applicable RM's.
    b. Because the control and corrective action function 
encompasses a variety of policies, specifications, standards, and 
corrective measures, this procedure treats QC requirements in 
general terms to allow each source owner or operator to develop a QC 
system that is most effective and efficient for the circumstances.

2. Definitions

    2.1  Continuous Emission Monitoring System (CEMS). The total 
equipment required for the determination of a pollutant 
concentration. The system consists of the following major 
subsystems:
    2.1.1  Sample Interface. That portion of the CEMS used for one 
or more of the following: sample acquisition, sample transport, and 
sample conditioning, or protection of the monitor from the effects 
of the stack effluent.
    2.1.2  Pollutant Analyzer. That portion of the CEMS that senses 
the pollutant concentration and generates a proportional output.
    2.1.3  Diluent Analyzer. That portion of the CEMS that senses 
the diluent gas (O2) and generates an output proportional to the gas 
concentration.
    2.1.4  Data Recorder. That portion of the CEMS that provides a 
permanent record of the analyzer output. The data recorder may 
provide automatic data reduction and CEMS control capabilities.
    2.2  Relative Accuracy (RA). The absolute mean difference 
between the pollutant concentration determined by the CEMS and the 
value determined by the reference method (RM) plus the 2.5 percent 
error confidence coefficient of a series of test divided by the mean 
of the RM tests or the applicable emission limit.
    2.3  Calibration Drift (CD). The difference in the CEMS output 
readings from the established reference value after a stated period 
of operation during which no unscheduled maintenance, repair, or 
adjustment took place.
    2.4  Zero Drift (ZD). The difference in CEMS output readings at 
the zero pollutant level after a stated period of operation during 
which no unscheduled maintenance, repair, or adjustment took place.
    2.5  Calibration Standard. Calibration standards produce a known 
and unchanging response when presented to the pollutant analyzer 
portion of the CEMS, and are used to calibrate the drift or response 
of the analyzer.
    2.6  Relative Accuracy Test Audit (RATA). Comparison of CEMS 
measurements to reference method measurements in order to evaluate 
relative accuracy following procedures and specification given in 
the appropriate performance specification.
    2.7  Absolute Calibration Audit (ACA). Equivalent to calibration 
error (CE) test defined in the appropriate performance specification 
using NIST traceable calibration standards to challenge the CEMS and 
assess accuracy.
    2.8  Rolling Average. The average emissions, based on some 
(specified) time period, calculated every minute from a one-minute 
average of four measurements taken at 15-second intervals. CEMS 
other than carbon monoxide and total hydrocarbon CEMS may have 
rolling averages calculated every hour from a one-hour average of at 
least four measurements taken at intervals not exceeding 15 minutes.

c. QA/QC Requirements

    3.1  QC Requirements. a. Each owner or operator must develop and 
implement a QC program. At a minimum, each QC program must include 
written procedures describing in detail complete, step-by-step 
procedures and operations for the following activities.
    1. Checks for component failures, leaks, and other abnormal 
conditions.
    2. Calibration of CEMS.
    3. CD determination and adjustment of CEMS.
    4. Integration of CEMS with the automatic waste feed cutoff 
(AWFCO) system.
    5. Preventive Maintenance of CEMS (including spare parts 
inventory).
    6. Data recording, calculations, and reporting.
    7. Checks of record keeping.
    8. Accuracy audit procedures, including sampling and analysis 
methods.
    9. Program of corrective action for malfunctioning CEMS.
    10. Operator training and certification.
    11. Maintaining and ensuring current certification or naming of 
cylinder gasses, metal solutions, and particulate samples used for 
audit and accuracy tests, daily checks, and calibrations.
    b. Whenever excessive inaccuracies occur for two consecutive 
quarters, the current written procedures must be revised or the CEMS 
modified or replaced to correct the deficiency causing the excessive 
inaccuracies. These written procedures must be kept on record and 
available for inspection by the enforcement agency.
    3.2  QA Requirements. Each source owner or operator must develop 
and implement a QA plan that includes, at a minimum, the following.

[[Page 53069]]

    1. QA responsibilities (including maintaining records, preparing 
reports, reviewing reports).
    2. Schedules for the daily checks, periodic audits, and 
preventive maintenance.
    3. Check lists and data sheets.
    4. Preventive maintenance procedures.
    5. Description of the media, format, and location of all records 
and reports.
    6. Provisions for a review of the CEMS data at least once a 
year. Based on the results of the review, the owner or operator must 
revise or update the QA plan, if necessary.

d. CD and ZD Assessment and Daily System Audit

    4.1  CD and ZD Requirement. Owners and operators must check, 
record, and quantify the ZD and the CD at least once daily 
(approximately 24 hours) in accordance with the method prescribed by 
the manufacturer. The CEMS calibration must, at a minimum, be 
adjusted whenever the daily ZD or CD exceeds the limits in the 
Performance Specifications. If, on any given ZD and/or CD check the 
ZD and/or CD exceed(s) two times the limits in the Performance 
Specifications, or if the cumulative adjustment to the ZD and/or CD 
(see Section 4.2) exceed(s) three times the limits in the 
Performance Specifications, hazardous waste burning must immediately 
cease and the CEMS must be serviced and recalibrated. Hazardous 
waste burning cannot resume until the owner or operator documents 
that the CEMS is in compliance with the Performance Specifications 
by carrying out an ACA.
    4.2  Recording Requirements for Automatic ZD and CD Adjusting 
Monitors. Monitors that automatically adjust the data to the 
corrected calibration values must record the unadjusted 
concentration measurement prior to resetting the calibration, if 
performed, or record the amount of the adjustment.
    4.3  Daily System Audit. The audit must include a review of the 
calibration check data, an inspection of the recording system, an 
inspection of the control panel warning lights, and an inspection of 
the sample transport and interface system (e.g., flowmeters, 
filters, etc.) as appropriate.
    4.4  Data Recording and Reporting. All measurements from the 
CEMS must be retained in the operating record for at least 5 years.

5. Performance Evaluation

    Carbon Monoxide (CO), Oxygen (O2), and Hydrocarbon 
(HC) CEMS. An Absolute Calibration Audit (ACA) must be conducted 
quarterly, and a Relative Accuracy Test Audit (RATA) (if applicable, 
see sections 5.1 and 5.2) must be conducted yearly. An Interference 
Response Tests must be performed whenever an ACA or a RATA is 
conducted. When a performance test is also required under 
Sec. 63.1207 to document compliance with emission standards, the 
RATA must coincide with the performance test. The audits must be 
conducted as follows.
    5.1  Relative Accuracy Test Audit (RATA). This requirement 
applies to O2 and CO CEMS. The RATA must be conducted at 
least yearly. Conduct the RATA as described in the RA test procedure 
(or alternate procedures section) described in the applicable 
Performance Specifications. In addition, analyze the appropriate 
performance audit samples received from the EPA as described in the 
applicable sampling methods.
    5.2  Absolute Calibration Audit (ACA). The ACA must be conducted 
at least quarterly except in a quarter when a RATA (if applicable, 
see section 5.1) is conducted instead. Conduct an ACA as described 
in the calibration error (CE) test procedure described in the 
applicable Performance Specifications.
    5.3  Interference Response Test. The interference response test 
must be conducted whenever an ACA or RATA is conducted. Conduct an 
interference response test as described in the applicable 
Performance Specifications.
    5.4  Excessive Audit Inaccuracy. If the RA from the RATA or the 
CE from the ACA exceeds the criteria in the applicable Performance 
Specifications, hazardous waste burning must cease immediately. 
Hazardous waste burning cannot resume until the owner or operator 
takes corrective measures and audit the CEMS with a RATA to document 
that the CEMS is operating within the specifications.

6. Other Requirements

    6.1  Performance Specifications. CEMS used by owners and 
operators of HWCs must comply with the following performance 
specifications in appendix B to part 60 of this chapter:

              Table I: Performance Specifications for CEMS
------------------------------------------------------------------------
                                                            Performance
                           CEMS                            specification
------------------------------------------------------------------------
Carbon monoxide..........................................          4B
Oxygen...................................................          4B
Total hydrocarbons.......................................          8A
------------------------------------------------------------------------

    6.2  Downtime due to Calibration. Facilities may continue to 
burn hazardous waste for a maximum of 20 minutes while calibrating 
the CEMS. If all CEMS are calibrated at once, the facility must have 
twenty minutes to calibrate all the CEMS. If CEMS are calibrated 
individually, the facility must have twenty minutes to calibrate 
each CEMS. If the CEMS are calibrated individually, other CEMS must 
be operational while the individual CEMS is being calibrated.
    6.3  Span of the CEMS.
    6.3.1  CO CEMS. The CO CEM must have two ranges, a low range 
with a span of 200 ppmv and a high range with a span of 3000 ppmv at 
an oxygen correction factor of 1. A one-range CEM may be used, but 
it must meet the performance specifications for the low range in the 
specified span of the low range.
    6.3.2  O2 CEMS. The O2 CEM must have a 
span of 25 percent. The span may be higher than 25 percent if the 
O2 concentration at the sampling point is greater than 25 
percent.
    6.3.3  HC CEMS. The HC CEM must have a span of 100 ppmv, 
expressed as propane, at an oxygen correction factor of 1.
    6.3.4  CEMS Span Values. When the Oxygen Correction Factor is 
Greater than 2. When an owner or operator installs a CEMS at a 
location of high ambient air dilution, i.e., where the maximum 
oxygen correction factor as determined by the permitting agency is 
greater than 2, the owner or operator must install a CEM with a 
lower span(s), proportionate to the larger oxygen correction factor, 
than those specified above.
    6.3.5  Use of Alternative Spans. Owner or operators may request 
approval to use alternative spans and ranges to those specified. 
Alternate spans must be approved in writing in advance by the 
Administrator. In considering approval of alternative spans and 
ranges, the Administrator will consider that measurements beyond the 
span will be recorded as values at the maximum span for purposes of 
calculating rolling averages.
    6.3.6  Documentation of Span Values. The span value must be 
documented by the CEMS manufacturer with laboratory data.
    6.4.1  Moisture Correction. Method 4 of appendix A, part 60 of 
this chapter, must be used to determine moisture content of the 
stack gasses.
    6.4.2  Oxygen Correction Factor. Measured pollutant levels must 
be corrected for the amount of oxygen in the stack according to the 
following formula:
[GRAPHIC] [TIFF OMITTED] TR30SE99.022

Where:
Pc = concentration of the pollutant or standard corrected 
to 7 percent oxygen, dry basis;
Pm = measured concentration of the pollutant, dry basis;
E = volume fraction of oxygen in the combustion air fed into the 
device, on a dry basis (normally 21 percent or 0.21 if only air is 
fed);
Y = measured fraction of oxygen on a dry basis at the sampling 
point.

    The oxygen correction factor is:
    [GRAPHIC] [TIFF OMITTED] TR30SE99.023
    
    6.4.3  Temperature Correction. Correction values for temperature 
are obtainable from standard reference materials.
    6.5  Rolling Average. A rolling average is the arithmetic 
average of all one-minute averages over the averaging period.
    6.5.1  One-Minute Average for CO and HC CEMS and Operating 
Parameter Limits. One-minute averages are the arithmetic average of 
the four most recent 15-second observations and must be calculated 
using the following equation:
[GRAPHIC] [TIFF OMITTED] TR30SE99.024

Where:

c = the one minute average
ci = a fifteen-second observation from the CEM

    Fifteen second observations must not be rounded or smoothed. 
Fifteen-second observations may be disregarded only as a

[[Page 53070]]

result of a failure in the CEMS and allowed in the source's quality 
assurance plan at the time of the CMS failure. One-minute averages 
must not be rounded, smoothed, or disregarded.
    6.5.2  Ten Minute Rolling Average Equation. The ten minute 
rolling average must be calculated using the following equation:
[GRAPHIC] [TIFF OMITTED] TR30SE99.025

Where:

CRA = The concentration of the standard, expressed as a 
rolling average
ci = a one minute average

    6.5.3  Hourly Rolling Average Equation for CO and THC CEMS and 
Operating Parameter Limits. The rolling average, based on a specific 
number integer of hours, must be calculated using the following 
equation:

[GRAPHIC] [TIFF OMITTED] TR30SE99.026

Where:

cRA = The concentration of the standard, expressed as a 
rolling average
ci = a one minute average

    6.5.4  Averaging Periods for CEMS other than CO and THC. The 
averaging period for CEMS other than CO and THC CEMS must be 
calculated as a rolling average of all one-hour values over the 
averaging period. An hourly average is comprised of 4 measurements 
taken at equally spaced time intervals, or at most every 15 minutes. 
Fewer than 4 measurements might be available within an hour for 
reasons such as facility downtime or CEMS calibration. If at least 
two measurements (30 minutes of data) are available, an hourly 
average must be calculated. The n-hour rolling average is calculated 
by averaging the n most recent hourly averages.
    6.6  Units of the Standards for the Purposes of Recording and 
Reporting Emissions. Emissions must be recorded and reported 
expressed after correcting for oxygen, temperature, and moisture. 
Emissions must be reported in metric, but may also be reported in 
the English system of units, at 7 percent oxygen, 20 deg.C, and on a 
dry basis.
    6.7  Rounding and Significant Figures. Emissions must be rounded 
to two significant figures using ASTM procedure E-29-90 or its 
successor. Rounding must be avoided prior to rounding for the 
reported value.

7. Bibliography

    1. 40 CFR Part 60, Appendix F, ``Quality Assurance Procedures: 
Procedure 1. Quality Assurance Requirements for Gas Continuous 
Emission Monitoring Systems Used For Compliance Determination''.

Subpart LLL--National Emission Standards for Hazardous Air 
Pollutants From the Portland Cement Manufacturing Industry

    3. Section 63.1350 is amended by revising paragraph (k) to read as 
follows:


Sec. 63.1350  Monitoring requirements.

* * * * *
    (k) The owner or operator of an affected source subject to a 
particulate matter standard under Sec. 63.1343 shall install, 
calibrate, maintain, and operate a particulate matter continuous 
emission monitoring system (PM CEMS) to measure the particulate matter 
discharged to the atmosphere. All requirements relating to 
installation, calibration, maintenance, operation or performance of the 
PM CEMS and implementation of the PM CEMS requirement are deferred 
pending further rulemaking.
* * * * *

PART 260--HAZARDOUS WASTE MANAGEMENT SYSTEM: GENERAL

    1. The authority citation for part 260 continues to read as 
follows:

    Authority: 42 U.S.C. 6905, 6912(a), 6921-6927, 6930, 6934, 6935, 
6937, 6938, 6939, and 6974.

Subpart B--Definitions

    2. Section 260.10 is amended by adding definitions in alphabetical 
order to read as follows:


Sec. 260.10  Definitions.

* * * * *
    Dioxins and furans (D/F) means tetra, penta, hexa, hepta, and octa-
chlorinated dibenzo dioxins and furans.
* * * * *
    TEQ means toxicity equivalence, the international method of 
relating the toxicity of various dioxin/furan congeners to the toxicity 
of 2,3,7,8-tetrachlorodibenzo-p-dioxin.
* * * * *

PART 261--IDENTIFICATION AND LISTING OF HAZARDOUS WASTE

    1. The authority citation for part 261 continues to read as 
follows:

    Authority: 42 U.S.C. 6905, 6912(a), 6921, 6922, 6924(y), and 
6938.

    2. Section 261.38 is amended by revising Table 1 to read as 
follows:


Sec. 261.38  Comparable/Syngas Fuel Exclusion.

* * * * *

        Table 1 to Sec.  261.38.--Detection and Detection Limit Values for Comparable Fuel Specification
----------------------------------------------------------------------------------------------------------------
                                                                                                        Minimum
                                                                   Composite   Heating  Concentration   required
                   Chemical name                        CAS No.      value      value   limit  (mg/kg  detection
                                                                    (mg/kg)   (BTU/lb)  at 10,000 BTU/ limit (mg/
                                                                                             lb)          kg)
----------------------------------------------------------------------------------------------------------------
Total Nitrogen as N................................            NA       9000     18400      4900       .........
Total Halogens as Cl...............................            NA       1000     18400       540       .........
Total Organic Halogens as Cl.......................            NA  .........  ........     (\1\)       .........
Polychlorinated biphenyls, total [Arocolors, total]     1336-36-3         ND  ........        ND             1.4
Cyanide, total.....................................       57-12-5         ND  ........        ND             1.0
Metals:
    Antimony, total................................   7440-36-012         ND  ........         0.23    .........
    Arsenic, total.................................     7440-38-2         ND  ........         0.23    .........
    Barium, total..................................     7440-39-3         ND  ........        23       .........
    Beryllium, total...............................     7440-41-7         ND  ........         1.2     .........
    Cadmium, total.................................     7440-43-9  .........        ND  .............        1.2
    Chromium, total................................     7440-47-3         ND  ........         2.3     .........
    Cobalt.........................................     7440-48-4         ND  ........         4.6     .........
    Lead, total....................................     7439-92-1         57     18100        31       .........
    Manganese......................................     7439-96-5         ND  ........         1.2     .........
    Mercury, total.................................     7439-97-6         ND  ........         0.25    .........
    Nickel, total..................................     7440-02-0        106     18400        58       .........
    Selenium, total................................     7782-49-2         ND  ........         0.23    .........

[[Page 53071]]

 
    Silver, total..................................     7440-22-4         ND  ........         2.3     .........
    Thallium, total................................     7440-28-0         ND  ........        23       .........
Hydrocarbons:
    Benzo[a]anthracene.............................       56-55-3         ND  ........      2400       .........
    Benzene........................................       71-43-2       8000     19600      4100       .........
    Benzo[b]fluoranthene...........................      205-99-2         ND  ........      2400       .........
    Benzo[k]fluoranthene...........................      207-08-9         ND  ........      2400       .........
    Benzo[a]pyrene.................................       50-32-8         ND  ........      2400       .........
    Chrysene.......................................      218-01-9         ND  ........      2400       .........
    Dibenzo[a,h]anthracene.........................       53-70-3         ND  ........      2400       .........
    7,12-Dimethylbenz[a]anthracene.................       57-97-6         ND  ........      2400       .........
    Fluoranthene...................................      206-44-0         ND  ........      2400       .........
    Indeno(1,2,3-cd)pyrene.........................      193-39-5         ND  ........      2400       .........
    3-Methylcholanthrene...........................       56-49-5         ND  ........      2400       .........
    Naphthalene....................................       91-20-3       6200     19400      3200       .........
    Toluene........................................      108-88-3      69000     19400     36000       .........
Oxygenates:
    Acetophenone...................................       98-86-2         ND  ........      2400       .........
    Acrolein.......................................      107-02-8         ND  ........        39       .........
    Allyl alcohol..................................      107-18-6         ND  ........        30       .........
    Bis(2-ethylhexyl)phthalate [Di-2-ethylhexyl          117-81-7         ND  ........      2400       .........
     phthalate]....................................
    Butyl benzyl phthalate.........................       85-68-7         ND  ........      2400       .........
    o-Cresol [2-Methyl phenol].....................       95-48-7         ND  ........      2400       .........
    m-Cresol [3-Methyl phenol].....................      108-39-4         ND  ........      2400       .........
    p-Cresol [4-Methyl phenol].....................      106-44-5         ND  ........      2400       .........
    Di-n-butyl phthalate...........................       84-74-2         ND  ........      2400       .........
    Diethyl phthalate..............................       84-66-2         ND  ........      2400       .........
    2,4-Dimethylphenol.............................      105-67-9         ND  ........      2400       .........
    Dimethyl phthalate.............................      131-11-3         ND  ........      2400       .........
    Di-n-octyl phthalate...........................      117-84-0         ND  ........      2400       .........
    Endothall......................................      145-73-3         ND  ........       100       .........
    Ethyl methacrylate.............................       97-63-2         ND  ........        39       .........
    2-Ethoxyethanol [Ethylene glycol monoethyl           110-80-5         ND  ........       100       .........
     ether]........................................
    Isobutyl alcohol...............................       78-83-1         ND  ........        39       .........
    Isosafrole.....................................      120-58-1         ND  ........      2400       .........
    Methyl ethyl ketone [2-Butanone]...............       78-93-3         ND  ........        39       .........
    Methyl methacrylate............................       80-62-6         ND  ........        39       .........
    1,4-Naphthoquinone.............................      130-15-4         ND  ........      2400       .........
    Phenol.........................................      108-95-2         ND  ........      2400       .........
    Propargyl alcohol [2-Propyn-1-ol]..............      107-19-7         ND  ........        30       .........
    Safrole........................................       94-59-7         ND  ........      2400       .........
Sulfonated Organics:
    Carbon disulfide...............................       75-15-0         ND  ........        ND            39
    Disulfoton.....................................      298-04-4         ND  ........        ND          2400
    Ethyl methanesulfonate.........................       62-50-0         ND  ........        ND          2400
    Methyl methanesulfonate........................       66-27-3         ND  ........        ND          2400
    Phorate........................................      298-02-2         ND  ........        ND          2400
    1,3-Propane sultone............................     1120-71-4         ND  ........        ND           100

[[Page 53072]]

 
    Tetraethyldithiopyrophosphate [Sulfotepp]......     3689-24-5         ND  ........        ND          2400
    Thiophenol [Benzenethiol]......................      108-98-5         ND  ........        ND            30
    O,O,O-Triethyl phosphorothioate................      126-68-1         ND  ........        ND          2400
Nitrogenated Organics:
    Acetonitrile [Methyl cyanide]..................       75-05-8         ND  ........        ND            39
    2-Acetylaminofluorene [2-AAF]..................       53-96-3         ND  ........        ND          2400
    Acrylonitrile..................................      107-13-1         ND  ........        ND            39
    4-Aminobiphenyl................................       92-67-1         ND  ........        ND          2400
    4-Aminopyridine................................      504-24-5         ND  ........        ND           100
    Aniline........................................       62-53-3         ND  ........        ND          2400
    Benzidine......................................       92-87-5         ND  ........        ND          2400
    Dibenz[a,j]acridine............................      224-42-0         ND  ........        ND          2400
    O,O-Diethyl O-pyrazinyl phosphorothioate             297-97-2         ND  ........        ND          2400
     [Thionazin]...................................
    Dimethoate.....................................       60-51-5         ND  ........        ND          2400
    p-(Dimethylamino) azobenzene [4-Dime                  60-11-7         ND  ........        ND          2400
     thylaminoazobenzene]..........................
    3,3'-Dimethylbenzidine.........................      119-93-7         ND  ........        ND          2400
    ,-Dimethylphenethylamine.....      122-09-8         ND  ........        ND          2400
    3,3'-Dimethoxybenzidine........................      119-90-4         ND  ........        ND           100
    1,3-Dinitrobenzene [m-Dinitrobenzene]..........       99-65-0         ND  ........        ND          2400
    4,6-Dinitro-o-cresol...........................      534-52-1         ND  ........        ND          2400
    2,4-Dinitrophenol..............................       51-28-5         ND  ........        ND          2400
    2,4-Dinitrotoluene.............................      121-14-2         ND  ........        ND          2400
    2,6-Dinitrotoluene.............................      606-20-2         ND  ........        ND          2400
    Dinoseb [2-sec-Butyl-4,6-dinitrophenol]........       88-85-7         ND  ........        ND          2400
    Diphenylamine..................................      122-39-4         ND  ........        ND          2400
    Ethyl carbamate [Urethane].....................       51-79-6         ND  ........        ND           100
    Ethylenethiourea (2-Imidazolidinethione).......       96-45-7         ND  ........        ND           110
    Famphur........................................       52-85-7         ND  ........        ND          2400
    Methacrylonitrile..............................      126-98-7         ND  ........        ND            39
    Methapyrilene..................................       91-80-5         ND  ........        ND          2400
    Methomyl.......................................    16752-77-5         ND  ........        ND            57
    2-Methyllactonitrile, [Acetone cyanohydrin]....       75-86-5         ND  ........        ND           100
    Methyl parathion...............................      298-00-0         ND  ........        ND          2400
    MNNG (N-Metyl-N-nitroso-N'-nitroguanidine).....       70-25-7         ND  ........        ND           110
    1-Naphthylamine, [-Naphthylamine].....      134-32-7         ND  ........        ND          2400
    2-Naphthylamine, [-Naphthylamine].....       91-59-8         ND  ........        ND          2400
    Nicotine.......................................       54-11-5         ND  ........        ND           100
    4-Nitroaniline, [p-Nitroaniline]...............      100-01-6         ND  ........        ND          2400
    Nitrobenzene...................................       98-95-3         ND  ........        ND          2400
    p-Nitrophenol, [p-Nitrophenol].................      100-02-7         ND  ........        ND          2400
    5-Nitro-o-toluidine............................       99-55-8         ND  ........        ND          2400
    N-Nitrosodi-n-butylamine.......................      924-16-3         ND  ........        ND          2400
    N-Nitrosodiethylamine..........................       55-18-5         ND  ........        ND          2400
    N-Nitrosodiphenylamine, [Diphenylnitrosamine]..       86-30-6         ND  ........        ND          2400
    N-Nitroso-N-methylethylamine...................    10595-95-6         ND  ........        ND          2400
    N-Nitrosomorpholine............................       59-89-2         ND  ........        ND          2400
    N-Nitrosopiperidine............................      100-75-4         ND  ........        ND          2400
    N-Nitrosopyrrolidine...........................      930-55-2         ND  ........        ND          2400
    2-Nitropropane.................................       79-46-9         ND  ........        ND            30
    Parathion......................................       56-38-2         ND  ........        ND          2400
    Phenacetin.....................................       62-44-2         ND  ........        ND          2400
    1,4-Phenylene diamine, [p-Phenylenediamine]....      106-50-3         ND  ........        ND          2400
    N-Phenylthiourea...............................      103-85-5         ND  ........        ND            57
    2-Picoline [alpha-Picoline]....................      109-06-8         ND  ........        ND          2400
    Propylthioracil, [6-Propyl-2-thiouracil].......       51-52-5         ND  ........        ND           100
    Pyridine.......................................      110-86-1         ND  ........        ND       24004700

[[Page 53073]]

 
    Strychnine.....................................       57-24-9         ND  ........        ND           100
    Thioacetamide..................................       62-55-5         ND  ........        ND            57
    Thiofanox......................................    39196-18-4         ND  ........        ND           100
    Thiourea.......................................       62-56-6         ND  ........        ND            57
    Toluene-2,4-diamine [2,4-Diaminotoluene].......       95-80-7         ND  ........        ND            57
    Toluene-2,6-diamine [2,6-Diaminotoluene].......      823-40-5         ND  ........        ND            57
    o-Toluidine....................................       95-53-4         ND  ........        ND          2400
    p-Toluidine....................................      106-49-0         ND  ........        ND           100
    1,3,5-Trinitrobenzene, [sym-Trinitobenzene]....       99-35-4         ND  ........        ND          2400
Halogenated Organic:
    Allyl chloride.................................      107-05-1         ND  ........        ND            39
    Aramite........................................      140-57-8         ND  ........        ND          2400
    Benzal chloride [Dichloromethyl benzene].......       98-87-3         ND  ........        ND           100
    Benzyl chloride................................     100-44-77         ND  ........        ND           100
    bis(2-Chloroethyl)ether [Dichoroethyl ether]...      111-44-4         ND  ........        ND          2400
    Bromoform [Tribromomethane]....................       75-25-2         ND  ........        ND            39
    Bromomethane [Methyl bromide]..................       74-83-9         ND  ........        ND            39
    4-Bromophenyl phenyl ether [p-Bromo diphenyl         101-55-3         ND  ........        ND          2400
     ether]........................................
    Carbon tetrachloride...........................       56-23-5         ND  ........        ND            39
    Chlordane......................................       57-74-9         ND  ........        ND            14
    p-Chloroaniline................................      106-47-8         ND  ........        ND          2400
    Chlorobenzene..................................      108-90-7         ND  ........        ND            39
    Chlorobenzilate................................      510-15-6         ND  ........        ND          2400
    p-Chloro-m-cresol..............................       59-50-7         ND  ........        ND          2400
    2-Chloroethyl vinyl ether......................      110-75-8         ND  ........        ND            39
    Chloroform.....................................       67-66-3         ND  ........        ND            39
    Chloromethane [Methyl chloride]................       74-87-3         ND  ........        ND        394700
    2-Chloronaphthalene [beta-Chloronaphthalene]...       91-58-7         ND  ........        ND          2400
    2-Chlorophenol [o-Chlorophenol]................       95-57-8         ND  ........        ND          2400
    Chloroprene [2-Chloro-1,3-butadiene]...........     1126-99-8         ND  ........        ND            39
    2,4-D [2,4-Dichlorophenoxyacetic acid].........       94-75-7         ND  ........        ND             7.0
    Diallate.......................................     2303-16-4         ND  ........        ND          2400
    1,2-Dibromo-3-chloropropane....................       96-12-8         ND  ........        ND            39
    1,2-Dichlorobenzene [o-Dichlorobenzene]........       95-50-1         ND  ........        ND          2400
    1,3-Dichlorobenzene [m-Dichlorobenzene]........      541-73-1         ND  ........        ND          2400
    1,4-Dichlorobenzene [p-Dichlorobenzene]........      106-46-7         ND  ........        ND          2400
    3,3'-Dichlorobenzidine.........................       91-94-1         ND  ........        ND          2400
    Dichlorodifluoromethane [CFC-12]...............       75-71-8         ND  ........        ND            39
    1,2-Dichloroethane [Ethylene dichloride].......      107-06-2         ND  ........        ND            39
    1,1-Dichloroethylene [Vinylidene chloride].....       75-35-4         ND  ........        ND            39
    Dichloromethoxy ethane [Bis(2-                       111-91-1         ND  ........        ND          2400
     chloroethoxy)methane..........................
    2,4-Dichlorophenol.............................      120-83-2         ND  ........        ND          2400
    2,6-Dichlorophenol.............................       87-65-0         ND  ........        ND          2400
    1,2-Dichloropropane [Propylene dichloride].....       78-87-5         ND  ........        ND            39
    cis-1,3-Dichloropropylene......................    10061-01-5         ND  ........        ND            39
    trans-1,3-Dichloropropylene....................    10061-02-6         ND  ........        ND            39
    1,3-Dichloro-2-propanol........................       96-23-1         ND  ........        ND            30
    Endosulfan I...................................      959-98-8         ND  ........        ND             1.4
    Endosulfan II..................................    33213-65-9         ND  ........        ND             1.4
    Endrin.........................................       72-20-8         ND  ........        ND             1.44700

[[Page 53074]]

 
    Endrin aldehyde................................     7421-93-4         ND  ........        ND             1.4
    Endrin Ketone..................................    53494-70-5         ND  ........        ND             1.4
    Epichlorohydrin [1-Chloro-2,3-epoxy propane]...      106-89-8         ND  ........        ND            30
    Ethylidene dichloride [1,1-Dichloroethane].....       75-34-3         ND  ........        ND            39
    2-Fluoroacetamide..............................      640-19-7         ND  ........        ND           100
    Heptachlor.....................................       76-44-8         ND  ........        ND             1.4
    Heptachlor epoxide.............................     1024-57-3         ND  ........        ND             2.8
    Hexachlorobenzene..............................      118-74-1         ND  ........        ND          2400
    Hexachloro-1,3-butadiene [Hexachlorobutadiene].       87-68-3         ND  ........        ND          2400
    Hexachlorocyclopentadiene......................       77-47-4         ND  ........        ND          2400
    Hexachloroethane...............................       67-72-1         ND  ........        ND          2400
    Hexachlorophene................................       70-30-4         ND  ........        ND         59000
    Hexachloropropene [Hexachloropropylene]........     1888-71-7         ND  ........        ND          2400
    Isodrin........................................      465-73-6         ND  ........        ND          2400
    Kepone [Chlordecone]...........................      143-50-0         ND  ........        ND          4700
    Lindane [gamma-BHC] [gamma-                           58-89-9         ND  ........        ND             1.4
     Hexachlorocyclohexane]........................
    Methylene chloride [Dichloromethane]...........       75-09-2         ND  ........        ND            39
    4,4'-Methylene-bis(2-chloroaniline)............      101-14-4         ND  ........        ND           100
    Methyl iodide [Iodomethane]....................       74-88-4         ND  ........        ND            39
    Pentachlorobenzene.............................      608-93-5         ND  ........        ND          2400
    Pentachloroethane..............................       76-01-7         ND  ........        ND            39
    Pentachloronitrobenzene [PCNB] [Quintobenzene]        82-68-8         ND  ........        ND          2400
     [Quintozene]..................................
    Pentachlorophenol..............................       87-86-5         ND  ........        ND          2400
    Pronamide......................................    23950-58-5         ND  ........        ND          2400
    Silvex [2,4,5-Trichlorophenoxypropionic acid]..       93-72-1         ND  ........        ND             7.0
    2,3,7,8-Tetrachlorodibenzo-p-dioxin [2,3,7,8-       1746-01-6         ND  ........        ND            30
     TCDD].........................................
    1,2,4,5-Tetrachlorobenzene.....................       95-94-3         ND  ........        ND          2400
    1,1,2,2-Tetrachloroethane......................       79-34-5         ND  ........        ND            39
    Tetrachloroethylene [Perchloroethylene]........      127-18-4         ND  ........        ND            39
    2,3,4,6-Tetrachlorophenol......................       58-90-2         ND  ........        ND          2400
    1,2,4-Trichlorobenzene.........................      120-82-1         ND  ........        ND          2400
    1,1,1-Trichloroethane [Methyl chloroform]......       71-55-6         ND  ........        ND            39
    1,1,2-Trichloroethane [Vinyl trichloride]......       79-00-5         ND  ........        ND            39
    Trichloroethylene..............................       79-01-6         ND  ........        ND            39
    Trichlorofluoromethane                                75-69-4         ND  ........        ND            39
     [Trichlormonofluoromethane]...................
    2,4,5-Trichlorophenol..........................       95-95-4         ND  ........        ND          2400
    2,4,6-Trichlorophenol..........................       88-06-2         ND  ........        ND          2400
    1,2,3-Trichloropropane.........................       96-18-4         ND  ........        ND            39
    Vinyl Chloride.................................       75-01-4         ND  ........        ND           39
----------------------------------------------------------------------------------------------------------------
Notes:
NA--Not Applicable.
ND--Nondetect.
\1\ 25 or individual halogenated organics listed below.

* * * * *

PART 264--STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE 
TREATMENT, STORAGE, AND DISPOSAL FACILITIES

    1. The authority citation for part 264 continues to read as 
follows:

    Authority: 42 U.S.C. 6905, 6912(a), 6924, and 6925.

    2. Section 264.340 is amended by redesignating paragraphs (b), (c), 
and (d) as paragraphs (c), (d), and (e), respectively, and adding 
paragraph (b), to read as follows:


Sec. 264.340  Applicability.

* * * * *
    (b) Integration of the MACT standards. (1) Except as provided by 
paragraph (b)(2) of this section, the standards of this part no longer 
apply when an owner or operator demonstrates compliance with the 
maximum achievable control technology (MACT) requirements of part 63, 
subpart EEE of this chapter by conducting a comprehensive performance 
test and submitting to the Administrator a Notification of Compliance 
under Secs. 63.1207(j) and 63.1210(d) of this chapter documenting 
compliance with the requirements of subpart EEE of part 63 of this 
Chapter. Nevertheless, even after this demonstration of compliance with 
the MACT standards, RCRA permit conditions that were based on the 
standards of this part will continue to be in effect until they are 
removed from the permit or the permit is terminated or revoked, unless 
the permit expressly provides otherwise.
    (2) The MACT standards do not replace the closure requirements of 
Sec. 264.351 or the applicable requirements of subparts A through H, BB 
and CC of this part.
* * * * *
    3. Section 264.601 is amended by revising the introductory text to 
read as follows:


Sec. 264.601  Environmental performance standards.

    A miscellaneous unit must be located, designed, constructed, 
operated,

[[Page 53075]]

maintained, and closed in a manner that will ensure protection of human 
health and the environment. Permits for miscellaneous units are to 
contain such terms and provisions as necessary to protect human health 
and the environment, including, but not limited to, as appropriate, 
design and operating requirements, detection and monitoring 
requirements, and requirements for responses to releases of hazardous 
waste or hazardous constituents from the unit. Permit terms and 
provisions must include those requirements of subparts I through O and 
subparts AA through CC of this part, part 270, part 63 subpart EEE, and 
part 146 of this chapter that are appropriate for the miscellaneous 
unit being permitted. Protection of human health and the environment 
includes, but is not limited to:
* * * * *

PART 265--INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF 
HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES

    1. The authority citation for part 265 continues to read as 
follows:

    Authority: 42 U.S.C. 6905, 6906, 6912, 6922, 6923, 6924, 6925, 
6935, 6936 and 6937.

    2. Section 265.340 is amended by redesignating paragraph (b) as 
paragraph (c), and adding paragraph (b), to read as follows:


Sec. 265.340  Applicability.

* * * * *
    (b) Integration of the MACT standards. (1) Except as provided by 
paragraph (b)(2) of this section, the standards of this part no longer 
apply when an owner or operator demonstrates compliance with the 
maximum achievable control technology (MACT) requirements of part 63, 
subpart EEE, of this chapter by conducting a comprehensive performance 
test and submitting to the Administrator a Notification of Compliance 
under Secs. 63.1207(j) and 63.1210(d) of this chapter documenting 
compliance with the requirements of part 63, subpart EEE of this 
chapter.
    (2) The following requirements continue to apply even where the 
owner or operator has demonstrated compliance with the MACT 
requirements of part 63, subpart EEE of this chapter: Sec. 265.351 
(closure) and the applicable requirements of subparts A through H, BB 
and CC of this part.
* * * * *

PART 266--STANDARDS FOR THE MANAGEMENT OF SPECIFIC HAZARDOUS WASTES 
AND SPECIFIC TYPES OF HAZARDOUS WASTE MANAGEMENT FACILITIES

    1. The authority citation for part 266 continues to read as 
follows:

    Authority: Secs. 1006, 2002 (a), 3004, 6905, 6906, 6912, 6922, 
6924, 6925, and 6937.

    2. Section 266.100 is amended by redesignating paragraphs (b), (c), 
(d), (e), and (f) as paragraphs (c), (d), (e), (f), and (g), adding 
paragraph (b), revising introductory text to newly designated paragraph 
(d)(1), revising the introductory text to newly designated paragraph 
(d)(3), and adding paragraph (h), to read as follows:


Sec. 266.100  Applicability.

* * * * *
    (b) Integration of the MACT standards. (1) Except as provided by 
paragraph (b)(2) of this section, the standards of this part no longer 
apply when an affected source demonstrates compliance with the maximum 
achievable control technology (MACT) requirements of part 63, subpart 
EEE, of this chapter by conducting a comprehensive performance test and 
submitting to the Administrator a Notification of Compliance under 
Secs. 63.1207(j) and 63.1210(d) of this chapter documenting compliance 
with the requirements of subpart EEE. Nevertheless, even after this 
demonstration of compliance with the MACT standards, RCRA permit 
conditions that were based on the standards of this part will continue 
to be in effect until they are removed from the permit or the permit is 
terminated or revoked, unless the permit expressly provides otherwise.
    (2) The following standards continue to apply:
    (i) The closure requirements of Secs. 266.102(e)(11) and 
266.103(l);
    (ii) The standards for direct transfer of Sec. 266.111;
    (iii) The standards for regulation of residues of Sec. 266.212; and
    (iv) The applicable requirements of subparts A through H, BB and CC 
of parts 264 and 265 of this chapter.
* * * * *
    (d) * * *
    (1) To be exempt from Secs. 266.102 through 266.111, an owner or 
operator of a metal recovery furnace or mercury recovery furnace must 
comply with the following requirements, except that an owner or 
operator of a lead or a nickel-chromium recovery furnace, or a metal 
recovery furnace that burns baghouse bags used to capture metallic 
dusts emitted by steel manufacturing, must comply with the requirements 
of paragraph (d)(3) of this section, and owners or operators of lead 
recovery furnaces that are subject to regulation under the Secondary 
Lead Smelting NESHAP must comply with the requirements of paragraph (h) 
of this section.
* * * * *
    (3) To be exempt from Secs. 266.102 through 266.111, an owner or 
operator of a lead or nickel-chromium or mercury recovery furnace, 
except for owners or operators of lead recovery furnaces subject to 
regulation under the Secondary Lead Smelting NESHAP,
* * * * *
    (h) Starting June 23, 1997, owners or operators of lead recovery 
furnaces that process hazardous waste for recovery of lead and that are 
subject to regulation under the Secondary Lead Smelting NESHAP, are 
conditionally exempt from regulation under this subpart, except for 
Sec. 266.101. To be exempt, an owner or operator must provide a one-
time notice to the Director identifying each hazardous waste burned and 
specifying that the owner or operator claims an exemption under this 
paragraph. The notice also must state that the waste burned has a total 
concentration of non-metal compounds listed in part 261, appendix VIII, 
of this chapter of less than 500 ppm by weight, as fired and as 
provided in paragraph (d)(2)(i) of this section, or is listed in 
appendix XI to this part 266.
    3. Section 266.101 is amended by revising paragraph (c)(1) to read 
as follows:


Sec. 266.101  Management prior to burning.

* * * * *
    (c) Storage and treatment facilities. (1) Owners and operators of 
facilities that store or treat hazardous waste that is burned in a 
boiler or industrial furnace are subject to the applicable provisions 
of parts 264, 265, and 270 of this chapter, except as provided by 
paragraph (c)(2) of this section. These standards apply to storage and 
treatment by the burner as well as to storage and treatment facilities 
operated by intermediaries (processors, blenders, distributors, etc.) 
between the generator and the burner.
* * * * *
    4. Section 266.105 is amended by redesignating paragraph (c) as 
paragraph (d) and adding paragraph (c), to read as follows:


Sec. 266.105  Standards to control particulate matter.

* * * * *

[[Page 53076]]

    (c) Oxygen correction. (1) Measured pollutant levels must be 
corrected for the amount of oxygen in the stack gas according to the 
formula:
[GRAPHIC] [TIFF OMITTED] TR30SE99.027

Where:
Pc is the corrected concentration of the pollutant in the stack gas, Pm 
is the measured concentration of the pollutant in the stack gas, E is 
the oxygen concentration on a dry basis in the combustion air fed to 
the device, and Y is the measured oxygen concentration on a dry basis 
in the stack.

    (2) For devices that feed normal combustion air, E will equal 21 
percent. For devices that feed oxygen-enriched air for combustion (that 
is, air with an oxygen concentration exceeding 21 percent), the value 
of E will be the concentration of oxygen in the enriched air.
    (3) Compliance with all emission standards provided by this subpart 
must be based on correcting to 7 percent oxygen using this procedure.
* * * * *
    5. Section 266.112, paragraph (b)(1) introductory text is amended 
by adding a sentence at the end and paragraph (b)(2)(i) is revised to 
read as follows:


Sec. 266.112  Regulation of residues.

* * * * *
    (b) * * *
    (1) * * * For polychlorinated dibenzo-p-dioxins and polychlorinated 
dibenzo-furans, analyses must be performed to determine specific 
congeners and homologues, and the results converted to 2,3,7,8-TCDD 
equivalent values using the procedure specified in section 4.0 of 
appendix IX of this part.
* * * * *
    (2) * * *
    (i) Nonmetal constituents. The concentration of each nonmetal toxic 
constituent of concern (specified in paragraph (b)(1) of this section) 
in the waste-derived residue must not exceed the health-based level 
specified in appendix VII of this part, or the level of detection 
(using analytical procedures prescribed in SW-846), whichever is 
higher. If a health-based limit for a constituent of concern is not 
listed in appendix VII of this part, then a limit of 0.002 micrograms 
per kilogram or the level of detection (using analytical procedures 
contained in SW-846, or other appropriate methods), whichever is 
higher, must be used. The levels specified in appendix VII of this part 
(and the default level of 0.002 micrograms per kilogram or the level of 
detection for constituents as identified in Note 1 of appendix VII of 
this paragraph) are administratively stayed under the condition, for 
those constituents specified in paragraph (b)(1) of this section, that 
the owner or operator complies with alternative levels defined as the 
land disposal restriction limits specified in Sec. 268.43 of this 
chapter for F039 nonwastewaters. In complying with those alternative 
levels, if an owner or operator is unable to detect a constituent 
despite documenting use of best good-faith efforts as defined by 
applicable Agency guidance or standards, the owner or operator is 
deemed to be in compliance for that constituent. Until new guidance or 
standards are developed, the owner or operator may demonstrate such 
good faith efforts by achieving a detection limit for the constituent 
that does not exceed an order of magnitude above the level provided by 
Sec. 268.43 of this chapter for F039 nonwastewaters. In complying with 
the Sec. 268.43 of this chapter F039 nonwastewater levels for 
polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-furans, 
analyses must be performed for total hexachlorodibenzo-p-dioxins, total 
hexachlorodibenzofurans, total pentachlorodibenzo-p-dioxins, total 
pentachlorodibenzofurans, total tetrachlorodibenzo-p-dioxins, and total 
tetrachlorodibenzofurans.

    Note to this paragraph: The administrative stay, under the 
condition that the owner or operator complies with alternative 
levels defined as the land disposal restriction limits specified in 
Sec. 268.43 of this chapter for F039 nonwastewaters, remains in 
effect until further administrative action is taken and notice is 
published in the Federal Register and the Code of Federal 
Regulations.
* * * * *
    6. Appendix VIII to part 266 is revised to read as follows:

Appendix VIII To Part 266.--Organic Compounds for Which Residues Must Be
                                Analyzed
------------------------------------------------------------------------
                 Volatiles                          Semivolatiles
------------------------------------------------------------------------
Benzene...................................  Bis(2-ethylhexyl)phthalate
Toluene...................................  Naphthalene
Carbon tetrachloride......................  Phenol
Chloroform................................  Diethyl phthalate
Methylene chloride........................  Butyl benzyl phthalate
Trichloroethylene.........................  2,4-Dimethylphenol
Tetra chloroethylene......................  o-Dichlorobenzene
1,1,1-Trichloroethane.....................  m-Dichlorobenzene
Chlorobenzene.............................  p-Dichlorobenzene
cis-1,4-Dichloro-2-butene.................  Hexachlorobenzene
Bromochloromethane........................  2,4,6-Trichlorophenol
Bromodichloromethane......................  Fluoranthene
Bromoform.................................  o-Nitrophenol
Bromomethane..............................  1,2,4-Trichlorobenzene
Methylene bromide.........................  o-Chlorophenol
Methyl ethyl ketone.......................  Pentachlorophenol
                                            Pyrene
                                            Dimethyl phthalate
                                            Mononitrobenzene
                                            2,6-Toluene diisocyanate
                                            Polychlorinated dibenzo-p-
                                             dioxins \1\
                                            Plychlorinated dibenzo-
                                             furans \1\
------------------------------------------------------------------------
\1\ Analyses for polychlorinated dibenzo-p-dioxins and polychlorinated
  dibenzo-furans are required only for residues collected from areas
  downstream of the combustion chamber (e.g., ductwork, boiler tubes,
  heat exchange surfaces, air pollution control devices, etc.).

PART 270--EPA ADMINISTERED PERMIT PROGRAMS: THE HAZARDOUS WASTE 
PERMIT PROGRAM

    1. The authority citation for part 270 continues to read as 
follows:

    Authority: 42 U.S.C. 6905, 6912, 6924, 6925, 6927, 6939, and 
6974.

    2. Section 270.19 is amended by revising the introductory text and 
adding paragraph (e) to read as follows:


Sec. 270.19  Specific part B information requirements for incinerators.

* * * * *
    Except as Sec. 264.340 of this Chapter and Sec. 270.19(e) provide 
otherwise, owners and operators of facilities that incinerate hazardous 
waste must fulfill the requirements of paragraphs (a), (b), or (c) of 
this section.
* * * * *
    (e) When an owner or operator demonstrates compliance with the air 
emission standards and limitations in 40 CFR part 63, subpart EEE, of 
this chapter (i.e., by conducting a comprehensive performance test and 
submitting a Notification of Compliance), the requirements of this 
section do not apply. Nevertheless, the Director may apply the 
provisions of this section, on a case-by-case basis, for purposes of 
information collection in accordance with Secs. 270.10(k) and 
270.32(b)(2).
    3. Section 270.22 is amended by adding introductory text to read as 
follows:

[[Page 53077]]

Sec. 270.22  Specific part B information requirements for boilers and 
industrial furnaces burning hazardous waste.

    When an owner or operator of a cement or lightweight aggregate kiln 
demonstrates compliance with the air emission standards and limitations 
in 40 CFR part 63, subpart EEE (i.e., by conducting a comprehensive 
performance test and submitting a Notification of Compliance), the 
requirements of this section do not apply. Nevertheless, the Director 
may apply the provisions of this section, on a case-by-case basis, for 
purposes of information collection in accordance with Secs. 270.10(k) 
and 270.32(b)(2).
* * * * *
    4. Appendix I to Sec. 270.42 is amended by adding an entry 8 in 
numerical order in section A and revising entry 9 in section L to read 
as follows:

               Table 1.--Regulations Implementing the Hazardous and solid Waste Amendments of 1984
----------------------------------------------------------------------------------------------------------------
                                   Title of
      Promulgation date           regulation          Federal Register reference            Effective date
----------------------------------------------------------------------------------------------------------------
 
*                  *                  *                  *                  *                  *
                                                        *
September 30, 1999...........  Standards for     [Insert FR page numbers]...........  September 30, 1999.
                                Hazardous Air
                                Pollutants for
                                Hazardous Waste
                                Combustors.
----------------------------------------------------------------------------------------------------------------



    Appendix I to Sec.  270.42--Classification of Permit Modification
------------------------------------------------------------------------
                          Modification                            Class
------------------------------------------------------------------------
A. General Permit Provisions:
 
                  *        *        *        *        *
  8. Changes to remove permit conditions that are no longer        \1\ 1
   applicable (i.e., because the standards upon which they are
   based are no longer applicable to the facility).
 
                  *        *        *        *        *
L. Incinerators, Boilers, and Industrial Furnaces:
 
                  *        *        *        *        *
  9. Technology Changes Needed to meet Standards under 40 CFR      \1\ 1
   part 63 (Subpart EEE--National Emission Standards for
   Hazardous Air Pollutants From Hazardous Waste Combustors),
   provided the procedures of Sec.  270.42(j) are followed.
 
                 *        *        *        *        *
------------------------------------------------------------------------
\1\ Class 1 modifications requiring prior Agency approval.

    5. Section 270.62 is amended by adding introductory text to read as 
follows:


Sec. 270.62  Hazardous waste incinerator permits.

    When an owner or operator demonstrates compliance with the air 
emission standards and limitations in 40 CFR part 63, subpart EEE 
(i.e., by conducting a comprehensive performance test and submitting a 
Notification of Compliance), the requirements of this section do not 
apply. Nevertheless, the Director may apply the provisions of this 
section, on a case-by-case basis, for purposes of information 
collection in accordance with Secs. 270.10(k) and 270.32(b)(2).
* * * * *
    6. Section 270.66 is amended by adding introductory text to read as 
follows:


Sec. 270.66  Permits for boilers and industrial furnaces burning 
hazardous waste.

    When an owner or operator of a cement or lightweight aggregate kiln 
demonstrates compliance with the air emission standards and limitations 
in 40 CFR part 63, subpart EEE (i.e., by conducting a comprehensive 
performance test and submitting a Notification of Compliance), the 
requirements of this section do not apply. Nevertheless, the Director 
may apply the provisions of this section, on a case-by-case basis, for 
purposes of information collection in accordance with Secs. 270.10(k) 
and 270.32(b)(2).
* * * * *

PART 271--REQUIREMENTS FOR AUTHORIZATION OF STATE HAZARDOUS WASTE 
PROGRAMS

    1. The authority citation for part 271 continues to read as 
follows:

    Authority: 42 U.S.C. 6905, 6912(a), and 6926.

    2. Section 271.1(j) is amended by adding the following entries to 
Table 1 in chronological order by date of publication in the Federal 
Register, to read as follows:


Sec. 271.1  Purpose and scope.

* * * * *
    (j) *  *  *

               Table 1.--Regulations Implementing the Hazardous and Solid Waste Amendments of 1984
----------------------------------------------------------------------------------------------------------------
                                                                Federal Register
         Promulgation date             Title of regulation          reference               Effective date
----------------------------------------------------------------------------------------------------------------
 
*                  *                  *                  *                  *                  *
                                                        *
September 30, 1999.................  Standards for           ......................  Sept. 30, 1999.
                                      Hazardous Air
                                      Pollutants for
                                      Hazardous Waste
                                      Combustors.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 99-20430 Filed 9-29-99; 8:45 am]
BILLING CODE 6560-50-U