[Federal Register Volume 69, Number 76 (Tuesday, April 20, 2004)]
[Proposed Rules]
[Pages 21198-21385]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-7858]



[[Page 21197]]

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Part II





Environmental Protection Agency





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40 CFR Parts 63, 264, et al.



National Emission Standards for Hazardous Air Pollutants: Proposed 
Standards for Hazardous Air Pollutants for Hazardous Waste Combustors 
(Phase I Final Replacement Standards and Phase II); Proposed Rule

  Federal Register / Vol. 69, No. 76 / Tuesday, April 20, 2004 / 
Proposed Rules  

[[Page 21198]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 63, 264, 265, 266, 270, and 271

[FRL-7644-1]
RIN 2050-AE01


National Emission Standards for Hazardous Air Pollutants: 
Proposed Standards for Hazardous Air Pollutants for Hazardous Waste 
Combustors (Phase I Final Replacement Standards and Phase II)

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: This action proposes national emission standards for hazardous 
air pollutants (NESHAP) for hazardous waste combustors. These 
combustors include hazardous waste burning incinerators, cement kilns, 
lightweight aggregate kilns, industrial/commercial/institutional 
boilers and process heaters, and hydrochloric acid production furnaces, 
known collectively as hazardous waste combustors (HWCs). EPA has 
identified these HWCs as major sources of hazardous air pollutant (HAP) 
emissions. These proposed standards will, when final, implement section 
112(d) of the Clean Air Act (CAA) by requiring hazardous waste 
combustors to meet HAP emission standards reflecting the application of 
the maximum achievable control technology (MACT).
    The HAP emitted by facilities in the incinerator, cement kiln, 
lightweight aggregate kiln, industrial/commercial/institutional boiler, 
process heater, and hydrochloric acid production furnace source 
categories include arsenic, beryllium, cadmium, chromium, dioxins and 
furans, hydrogen chloride and chlorine gas, lead, manganese, and 
mercury. Exposure to these substances has been demonstrated to cause 
adverse health effects such as irritation on the lung, skin, and mucus 
membranes, effects on the central nervous system, kidney damage, and 
cancer. The adverse health effects associated with the exposure to 
these specific HAP are further described in the preamble. In general, 
these findings have only been shown with concentrations higher than 
those typically in the ambient air.
    This action also presents our tentative decision regarding the 
February 28, 2002, petition for rulemaking submitted by the Cement Kiln 
Recycling Coalition to the Administrator, relating to EPA's 
implementation of the so-called omnibus permitting authority under 
section 3005(c) of the Resource Conservation and Recovery Act (RCRA), 
which requires that each permit issued under RCRA contain such terms 
and conditions as are determined necessary to protect human health and 
the environment. In that petition, the Cement Kiln Recycling Coalition 
requests that we repeal the existing site-specific risk assessment 
policy and technical guidance for hazardous waste combustors and that 
we promulgate the policy and guidance as rules in accordance with the 
Administrative Procedure Act if we continue to believe that site-
specific risk assessments may be necessary.

DATES: Submit comments on or before July 6, 2004.

ADDRESSES: Submit your comments, identified by Docket ID No. OAR-2004-
0022 by one of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov. Follow the on-line instructions for submitting 
comments.
     Agency Web site: http://www.epa.gov/edocket. 
EDOCKET, EPA's electronic public docket and comment system, is EPA's 
preferred method for receiving comments. Follow the on-line 
instructions for submitting comments.
     E-mail: http://www.epa.gov/edocket.
     Fax: 202-566-1741.
     Mail: OAR Docket, Environmental Protection 
Agency, Mailcode: B102, 1200 Pennsylvania Ave., NW., Washington, DC 
20460. Please include a total of 2 copies.
     Hand Delivery: EPA/DC, EPA West, Room B102, 1301 
Constitution Ave., NW., Washington, DC. Such deliveries are only 
accepted during the Docket's normal hours of operation, and special 
arrangements should be made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. OAR-2004-0022. 
EPA's policy is that all comments received will be included in the 
public docket without change and may be made available online at http://www.epa.gov/edocket, including any personal information provided, 
unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through EDOCKET, regulations.gov, or e-
mail. The EPA EDOCKET and the federal regulations.gov Web sites are 
``anonymous access'' systems, which means EPA will not know your 
identity or contact information unless you provide it in the body of 
your comment. If you send an e-mail comment directly to EPA without 
going through EDOCKET or regulations.gov, your e-mail address will be 
automatically captured and included as part of the comment that is 
placed in the public docket and made available on the Internet. If you 
submit an electronic comment, EPA recommends that you include your name 
and other contact information in the body of your comment and with any 
disk or CD-ROM you submit. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses. For additional information about EPA's public 
docket visit EDOCKET on-line or see the Federal Register of May 31, 
2002 (67 FR 38102).
    For additional instructions on submitting comments, go to unit II 
of the SUPPLEMENTARY INFORMATION section of this document.
    Docket: All documents in the docket are listed in the EDOCKET index 
at http://www.epa.gov/edocket. Although listed in the index, some 
information is not publicly available, i.e., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, is not placed on the Internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available either electronically in EDOCKET or in hard 
copy at the OAR Docket, EPA/DC, EPA West, Room B102, 1301 Constitution 
Ave., NW., Washington, DC. The Public Reading Room is open from 8:30 
a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The 
telephone number for the Public Reading Room is (202) 566-1744, and the 
telephone number for the OAR Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: For general information, call the RCRA 
Call Center at 1-800-424-9346 or TDD 1-800-553-7672 (hearing impaired). 
Callers within the Washington Metropolitan Area must dial 703-412-9810 
or TDD 703-412-3323 (hearing impaired). The RCRA Call Center is open 
Monday-Friday, 9 a.m. to 4 p.m., eastern standard time. For more 
information about this proposal, contact Michael Galbraith at 703-605-
0567, or [email protected].

SUPPLEMENTARY INFORMATION:

I. Regulated Entities

    The promulgation of the proposed rule would affect the following 
North

[[Page 21199]]

American Industrial Classification System (NAICS) and Standard 
Industrial Classification (SIC) codes:

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                                                                                         Examples of potentially
             Category                           NAICS code                 SIC code        regulated entities
----------------------------------------------------------------------------------------------------------------
Any industry that combusts         562211.............................            4953  Incinerator, hazardous
 hazardous waste as defined in                                                           waste.
 the proposed rule.
                                   327310.............................            3241  Cement manufacturing,
                                                                                         clinker production.
                                   327992.............................            3295  Ground or treated
                                                                                         mineral and earth
                                                                                         manufacturing.
                                   325................................              28  Chemical Manufacturers.
                                   324................................              29  Petroleum Refiners.
                                   331................................              33  Primary Aluminum.
                                   333................................              38  Photographic equipment
                                                                                         and supplies.
                                   488, 561, 562......................              49  Sanitary Services,
                                                                                         N.E.C.
                                   421................................              50  Scrap and waste
                                                                                         materials.
                                   422................................              51  Chemical and Allied
                                                                                         Products, N.E.C.
                                   512, 541, 561, 812.................              73  Business Services,
                                                                                         N.E.C.
                                   512, 514, 541, 711.................              89  Services, N.E.C.
                                   924................................              95  Air, Water and Solid
                                                                                         Waste Management.
----------------------------------------------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. This table lists examples of the types of entries EPA is now 
aware could potentially be regulated by this action. Other types of 
entities not listed could also be affected. To determine whether your 
facility, company, business, organization, etc., is regulated by this 
action, you should examine the applicability criteria in Part II of 
this preamble. If you have any questions regarding the applicability of 
this action to a particular entity, consult the person listed in the 
preceding FOR FURTHER INFORMATION CONTACT section.

II. What Should I Consider as I Prepare My Comments for EPA?

    1. Submitting CBI. Do not submit this information to EPA through 
EDOCKET, regulations.gov or e-mail. Clearly mark the part or all of the 
information that you claim to be CBI. For CBI information in a disk or 
CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as 
CBI and then identify electronically within the disk or CD-ROM the 
specific information that is claimed as CBI). In addition to one 
complete version of the comment that includes information claimed as 
CBI, a copy of the comment that does not contain the information 
claimed as CBI must be submitted for inclusion in the public docket. 
Information so marked will not be disclosed except in accordance with 
procedures set forth in 40 CFR part 2.
    2. Tips for Preparing Your Comments. When submitting comments, 
remember to:
    A. Identify the rulemaking by docket number and other identifying 
information (subject heading, Federal Register date and page number).
    B. Follow directions--The agency may ask you to respond to specific 
questions or organize comments by referencing a Code of Federal 
Regulations (CFR) part or section number.
    C. Explain why you agree or disagree; suggest alternatives and 
substitute language for your requested changes.
    D. Describe any assumptions and provide any technical information 
and/or data that you used.
    E. If you estimate potential costs or burdens, explain how you 
arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
    F. Provide specific examples to illustrate your concerns, and 
suggest alternatives.
    G. Explain your views as clearly as possible, avoiding the use of 
profanity or personal threats.
    H. Make sure to submit your comments by the comment period deadline 
identified.

Outline

Part One: Background and Summary

I. Background Information
    A. What Criteria Are Used in the Development of NESHAP?
    B. What Is the Regulatory Development Background of the Source 
Categories in the Proposed Rule?
    C. What Is the Statutory Authority for this Standard?
    D. What Is the Relationship Between the Proposed Rule and Other 
MACT Combustion Rules?
    E. What Are the Health Effects Associated with Pollutants 
Emitted by Hazardous Waste Combustors?
II. Summary of the Proposed Rule
    A. What Source Categories Are Affected by the Proposed Rule?
    B. What HAP Are Emitted?
    C. Does Today's Proposed Rule Apply to My Source?
    D. What Emissions Limitations Must I Meet?
    E. What Are the Testing and Initial Compliance Requirements?
    F. What Are the Continuous Compliance Requirements?
    G. What Are the Notification, Recordkeeping, and Reporting 
Requirements?

Part Two: Rationale for the Proposed Rule

I. How Did EPA Determine Which Hazardous Waste Combustion Sources 
Would Be Regulated?
    A. How Are Area Sources Regulated?
    B. What Hazardous Waste Combustors Are Not Covered by this 
Proposal?
    C. How Would Sulfuric Acid Regeneration Facilities Be Regulated?
II. What Subcategorization Considerations Did EPA Evaluate?
    A. What Subcategorization Options Did We Consider for 
Incinerators?
    B. What Subcategorization Options Did We Consider for Cement 
Kilns?
    C. What Subcategorization Options Did We Consider for 
Lightweight Aggregate Kilns?
    D. What Subcategorization Options Did We Consider for Boilers?
    E. What Subcategorization Options Did We Consider for 
Hydrochloric Acid Production Furnaces?
III. What Data and Information Did EPA Consider to Establish the 
Proposed Standards?
    A. Data Base for Phase I Sources
    B. Data Base for Phase II Sources
    C. Classification of the Emission Data
    D. Invitation to Comment on Data Base
IV. How Did EPA Select the Format for the Proposed Rule?
    A. What Is the Rationale for Generally Selecting an Emission 
Limit Format Rather than a Percent Reduction Format?
    B. What Is the Rationale for Selecting a Hazardous Waste Thermal 
Emissions Format for Some Standards, and an Emissions Concentration 
Format for Others?
    C. What Is the Rationale for Selecting Surrogates to Control 
Multiple HAP?
    D. What Is the Rationale for Requiring Compliance with Operating 
Parameter Limits to Ensure Compliance with Emission Standards?

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V. How Did EPA Determine the Proposed Emission Limitations for New 
and Existing Units?
    A. How Did EPA Determine the Proposed Emission Limitations for 
New Units?
    B. How Did EPA Determine the Proposed Emission Limitations for 
Existing Units?
VI. How Did EPA Determine the MACT Floor for Existing and New Units?
    A. What MACT Methodology Approaches Are Used to Identify the 
Best Performers for the Proposed Floors, and When Are They Applied?
    B. How Did EPA Select the Data to Represent Each Source When 
Determining Floor Levels?
    C. How Did We Evaluate Whether It Is Appropriate to Issue 
Separate Emissions Standards for Various Subcategories?
    D. How Did We Rank Each Source's Performance Levels to Identify 
the Best Performing Sources for the Three MACT Methodologies?
    E. How Did EPA Calculate Floor Levels That Are Achievable for 
the Average of the Best Performing Sources?
    F. Why Did EPA Default to the Interim Standards When 
Establishing Floors?
    G. What Other Options Did EPA Consider?
VII. How Did EPA Determine the Proposed Emission Standards for 
Hazardous Waste Burning Incinerators?
    A. What Are the Proposed Standards for Dioxin and Furan?
    B. What Are the Proposed Standards for Mercury?
    C. What Are the Proposed Standards for Particulate Matter?
    D. What Are the Proposed Standards for Semivolatile Metals?
    E. What Are the Proposed Standards for Low Volatile Metals?
    F. What Are the Proposed Standards for Hydrogen Chloride and 
Chlorine Gas?
    G. What Are the Standards for Hydrocarbons and Carbon Monoxide?
    H. What Are the Standards for Destruction and Removal 
Efficiency?
VIII. How Did EPA Determine the Proposed Emission Standards for 
Hazardous Waste Burning Cement Kilns?
    A. What Are the Proposed Standards for Dioxin and Furan?
    B. What Are the Proposed Standards for Mercury?
    C. What Are the Proposed Standards for Particulate Matter?
    D. What Are the Proposed Standards for Semivolatile Metals?
    E. What Are the Proposed Standards for Low Volatile Metals?
    F. What Are the Proposed Standards for Hydrogen Chloride and 
Chlorine Gas?
    G. What Are the Standards for Hydrocarbons and Carbon Monoxide?
    H. What Are the Standards for Destruction and Removal 
Efficiency?
IX. How Did EPA Determine the Proposed Emission Standards for 
Hazardous Waste Burning Lightweight Aggregate Kilns?
    A. What Are the Proposed Standards for Dioxin and Furan?
    B. What Are the Proposed Standards for Mercury?
    C. What Are the Proposed Standards for Particulate Matter?
    D. What Are the Proposed Standards for Semivolatile Metals?
    E. What Are the Proposed Standards for Low Volatile Metals?
    F. What Are the Proposed Standards for Hydrogen Chloride and 
Chlorine Gas?
    G. What Are the Standards for Hydrocarbons and Carbon Monoxide?
    H. What Are the Standards for Destruction and Removal 
Efficiency?
X. How Did EPA Determine the Proposed Emission Standards for 
Hazardous Waste Burning Solid Fuel-Fired Boilers?
    A. What Is the Rationale for the Proposed Standards for Dioxin 
and Furan?
    B. What Is the Rationale for the Proposed Standards for Mercury?
    C. What Is the Rationale for the Proposed Standards for 
Particulate Matter?
    D. What Is the Rationale for the Proposed Standards for 
Semivolatile Metals?
    E. What Is the Rationale for the Proposed Standards for Low 
Volatile Metals?
    F. What Is the Rationale for the Proposed Standards for Total 
Chlorine?
    G. What Is the Rationale for the Proposed Standards for Carbon 
Monoxide or Hydrocarbons?
    H. What Is the Rationale for the Proposed Standard for 
Destruction and Removal Efficiency?
XI. How Did EPA Determine the Proposed Emission Standards for 
Hazardous Waste Burning Liquid Fuel-Fired Boilers?
    A. What Are the Proposed Standards for Dioxin and Furan?
    B. What Is the Rationale for the Proposed Standards for Mercury?
    C. What Is the Rationale for the Proposed Standards for 
Particulate Matter?
    D. What Is the Rationale for the Proposed Standards for 
Semivolatile Metals?
    E. What Is the Rationale for the Proposed Standards for 
Chromium?
    F. What Is the Rationale for the Proposed Standards for Total 
Chlorine?
    G. What Is the Rationale for the Proposed Standards for Carbon 
Monoxide or Hydrocarbons?
    H. What Is the Rationale for the Proposed Standard for 
Destruction and Removal Efficiency?
XII. How Did EPA Determine the Proposed Emission Standards for 
Hazardous Waste Burning Hydrochloric Acid Production Furnaces?
    A. What Is the Rationale for the Proposed Standards for Dioxin 
and Furan?
    B. What Is the Rationale for the Proposed Standards for Mercury, 
Semivolatile Metals, and Low Volatile Metals?
    C. What Is the Rationale for the Proposed Standards for Total 
Chlorine?
    D. What Is the Rationale for the Proposed Standards for Carbon 
Monoxide or Hydrocarbons?
    E. What Is the Rationale for the Proposed Standard for 
Destruction and Removal Efficiency?
XIII. What Is the Rationale for Proposing An Alternative Risk-Based 
Standard for Total Chlorine in Lieu of the MACT Standard?
    A. What Is the Legal Authority to Establish Risk-Based 
Standards?
    B. What Is the Rationale for the National Exposure Standards?
    C. How Would You Determine if Your Total Chlorine Emission Rate 
Meets the Eligibility Requirements Defined by the National Exposure 
Standards?
    D. What Is the Rationale for Caps on the Risk-Based Emission 
Limits?
    E. What Would Your Risk-Based Eligibility Demonstration Contain?
    F. When Would You Complete and Submit Your Eligibility 
Demonstration?
    G. How Would the Risk-Based HCl-Equivalent Emission Rate Limit 
Be Implemented?
    H. How Would You Ensure that Your Facility Remains Eligible for 
the Risk-Based Emission Limit?
    I. Request for Comment on an Alternative Approach: Risk-Based 
National Emission Standards
XIV. How Did EPA Determine Testing and Monitoring Requirements for 
the Proposed Rule?
    A. What Is the Rationale for the Proposed Testing Requirements?
    B. What Are the Dioxin/Furan Testing Requirements for Boilers 
that Would Not Be Subject to a Numerical Dioxin/Furan Emission 
Standard?
    C. What Are the Proposed Test Methods?
    D. What Is the Rationale for the Proposed Continuous Monitoring 
Requirements?
    E. What Are the Averaging Periods for the Operating Parameter 
Limits, and How Are Performance Test Data Averaged to Calculate the 
Limits?
    F. How Would Sources Comply with Emissions Standards Based on 
Normal Emissions?
    G. How Would Sources Comply with Emission Standards Expressed as 
Hazardous Waste Thermal Emissions?
    H. What Happens if My Thermal Emissions Standard Limits 
Emissions to Below the Detection Limit of the Stack Test Methods?
    I. Are We Concerned About Possible Negative Biases Associated 
With Making Hydrogen Chloride Measurements in High Moisture 
Conditions?
    J. What Are the Other Proposed Compliance Requirements?
XV. How Did EPA Determine Compliance Times for this Proposed Rule?
XVI. How Did EPA Determine the Required Records and Reports for the 
Proposed Rule?
    A. Summary of Requirements Currently Applicable to Incinerators, 
Cement Kilns, and Lightweight Aggregate Kilns and that Would Be 
Applicable to Boilers and Hydrochloric Acid Production Furnaces
    B. Why Is EPA Proposing Notification of Intent to Comply and 
Compliance Progress Report Requirements?
XVII. What Are the Title V and RCRA Permitting Requirements for 
Phase I and Phase II Sources?
    A. What Is the General Approach to Permitting Hazardous Waste 
Combustion Sources?
    B. How Will the Replacement Standards Affect Permitting for 
Phase I Sources?
    C. What Permitting Requirements Is EPA Proposing for Phase II 
Sources?

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    D. How Would this Proposal Affect the RCRA Site-Specific Risk 
Assessment Policy?
XVIII. What Alternatives to the Particulate Matter Standard Is EPA 
Proposing or Requesting Comment On?
    A. What Alternative to the Particulate Matter Standard Is EPA 
Proposing for Incinerators, Liquid Fuel-Fired Boilers, and Solid 
Fuel-Fired Boilers?
    B. What Alternative to the Particulate Matter Standard Is EPA 
Requesting Comment On?
XIX. What Are the Proposed RCRA State Authorization and CAA 
Delegation Requirements?
    A. What Is the Authority for this Rule?
    B. Are There Any Changes to the CAA Delegation Requirements for 
Phase I Sources?
    C. What Are the Proposed CAA Delegation Requirements for Phase 
II Sources?

Part Three: Proposed Revisions to Compliance Requirements

I. Why Is EPA Proposing to Allow Phase I Sources to Conduct the 
Initial Performance Test to Comply with the Replacement Rules 12 
Months After the Compliance Date?
II. Why Is EPA Requesting Comment on Requirements Promulgated as 
Interim Standards or as Final Amendments?
    A. Interim Standards Amendments to the Startup, Shutdown, and 
Malfunction Plan Requirements
    B. Interim Standards Amendments to the Compliance Requirements 
for Ionizing Wet Scrubbers
    C. Why Is EPA Requesting Comment on the Fugitive Emission 
Requirements?
    D. Why Is EPA Requesting Comment on Bag Leak Detector 
Sensitivity?
    E. Final Amendments Waiving Operating Parameter Limits during 
Testing without an Approved Test Plan
III. Why Is EPA Requesting Comment on Issues and Amendments that 
Were Previously Proposed?
    A. Definition of Research, Development, and Demonstration Source
    B. Identification of an Organics Residence Time that Is 
Independent of, and Shorter than, the Hazardous Waste Residence Time
    C. Why Is EPA Not Proposing to Extend APCD Controls after the 
Residence Time Has Expired when Sources Operate under Alternative 
Section 112 or 129 Standards?
    D. Why Is EPA Proposing to Allow Use of Method 23 as an 
Alternative to Method 0023A for Dioxin/Furan?
    E. Why Is EPA Not Proposing the ``Matching the Profile'' 
Alternative Approach to Establish Operating Parameter Limits?
    F. Why Is EPA Not Proposing to Allow Extrapolation of OPLs?
    G. Why Is EPA Proposing to Delete the Limit on Minimum 
Combustion Chamber Temperature for Dioxin/Furan for Cement Kilns?
    H. Why Is EPA Requesting Additional Comment on Whether to Add a 
Maximum pH Limit for Wet Scrubbers to Control Mercury Emissions?
    I. How Is EPA Proposing to Ensure Performance of Electrostatic 
Precipitators, Ionizing Wet Scrubbers, and Fabric Filters?
IV. Other Proposed Compliance Revisions
    A. What Is the Proposed Clarification to the Public Notice 
Requirement for Approved Test Plans?
    B. What Is the Proposed Clarification to the Public Notice 
Requirement for the Petition to Waive a Performance Test?

Part Four: Impacts of the Proposed Rule

I. What Are the Air Impacts?
II. What Are the Water and Solid Waste Impacts?
III. What Are the Energy Impacts?
IV. What are the Control Costs?
V. Can We Achieve the Goals of the Proposed Rule in a Less Costly 
Manner?
VI. What are the Economic Impacts?
    A. Market Exit Estimates
    B. Quantity of Waste Reallocated
    C. Employment Impacts
VII. What Are the Benefits of Reductions in Particulate Matter 
Emissions?
VIII. What are the Social Costs and Benefits of the Proposed Rule?
    A. Combustion Market Overview
    B. Baseline Specification
    C. Analytical Methodology and Findings--Social Cost Analysis
    D. Analytical Methodology and Findings--Benefits Assessment
IX. How Does the Proposed Rule Meet the RCRA Protectiveness Mandate?
    A. Background
    B. Assessment of Risks

Part Five: Administrative Requirements

I. Executive Order 12866: Regulatory Planning and Review
II. Paperwork Reduction Act
III. Regulatory Flexibility Act
IV. Unfunded Mandates Reform Act
V. Executive Order 13132: Federalism
VI. Executive Order 13175: Consultation and Coordination with Indian 
Tribal Governments
VII. Executive Order 13045: Protection of Children from 
Environmental Health and Safety Risks
VIII. Executive Order 13211: Actions that Significantly Affect 
Energy Supply, Distribution, or Use
IX. National Technology Transfer and Advancement Act
X. Executive Order 12898: Federal Actions to Address Environmental 
Justice in Minority Populations and Low-Income Populations
XI. Congressional Review

Abbreviations and Acronyms Used in This Document

acfm--actual cubic feet per minute
Btu--British thermal units
CAA--Clean Air Act
CFR--Code of Federal Regulations
DRE--destruction and removal efficiency
dscf--dry standard cubic foot
dscm--dry standard cubic meter
EPA--Environmental Protection Agency
FR--Federal Register
gr/dscf--grains per dry standard cubic foot
HAP--hazardous air pollutant(s)
ICR--Information Collection Request
kg/hr--kilograms per hour
kW-hour--kilo Watt hour
MACT--Maximum Achievable Control Technology
mg/dscm--milligrams per dry standard cubic meter
MMBtu--million British thermal unit
ng/dscm--nanograms per dry standard cubic meter
NESHAP--national emission standards for HAP
ng--nanograms
POHC--principal organic hazardous constituent
ppmv--parts per million by volume
ppmw--parts per million by weight
Pub. L.--Public Law
RCRA--Resource Conservation and Recovery Act
SRE--system removal efficiency
TEQ--toxicity equivalence
ug/dscm--micrograms per dry standard cubic meter
U.S.C.--United States Code

Part One: Background and Summary

I. Background Information

A. What Criteria Are Used in the Development of NESHAP?

1. What Information Is Covered in This Preamble and How Is It 
Organized?
    In this preamble, EPA summarizes the important features of these 
proposed standards that apply to hazardous waste burning incinerators, 
cement kilns, lightweight aggregate kilns, boilers, and hydrochloric 
acid production furnaces, known collectively as HWCs. This preamble 
describes: (1) The environmental, energy, and economic impacts of these 
proposed standards; (2) the basis for each of the decisions made 
regarding the proposed standards; (3) requests public comments on 
certain issues; and (4) discusses administrative requirements relative 
to this action.
2. Where in the Code of Federal Regulations Will These Standards Be 
Codified?
    The Code of Federal Regulations (CFR) is a codification of the 
general and permanent rules published in the Federal Register by the 
Executive departments and agencies of the Federal Government. The code 
is divided into 50 titles that represent broad areas subject to Federal 
regulation. These proposed rules would be published in Title 40, 
Protection of the Environment, Part 63, Subpart EEE: National Emission 
Standards for Hazardous Air Pollutants From Hazardous Waste Combustors.

[[Page 21202]]

3. What Criteria Are Used in the Development of NESHAP?
    Section 112 of the Clean Air Act (CAA) requires EPA to promulgate 
regulations for the control of HAP emissions from each source category 
listed by EPA under section 112(c). The statute requires the 
regulations to reflect the maximum degree of reduction in emissions of 
HAP that is achievable taking into consideration the cost of achieving 
the emission reduction, any nonair quality health and environmental 
impacts, and energy requirements. This level of control is commonly 
referred to as MACT (i.e., maximum achievable control technology). The 
MACT regulation can be based on the emission reductions achievable 
through 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, 
substitutions 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 emission point; (4) design, equipment, work 
practices, or operational standards as provided in subsection 112(h); 
or (5) a combination of the above. See section 112(d)(2) of the CAA.
    For new sources, MACT standards cannot be less stringent than the 
emission control achieved in practice by the best-controlled similar 
source. See section 112(d)(3) of the Act. The MACT standards for 
existing sources can be less stringent than standards for new sources, 
but they cannot be less stringent than the average emission limitation 
achieved by the best-performing 12 percent of existing sources for 
categories and subcategories with 30 or more sources, or the best-
performing 5 sources for categories or subcategories with fewer than 30 
sources. Id. This level of control is usually referred to as the MACT 
``floor'', the term used in the Legislative History.
    In essence, MACT standards ensure that all major sources of air 
toxic (i.e., HAP) emissions achieve the level of control already being 
achieved by the better-controlled and lower-emitting sources in each 
category. This approach provides assurance to citizens that each major 
source of toxic air pollution will be required to effectively control 
its emissions of air toxics. At the same time, this approach provides a 
level playing field, ensuring that facilities that employ cleaner 
processes and good emission controls are not disadvantaged relative to 
competitors with poorer controls.

B. What Is the Regulatory Development Background of the Source 
Categories in the Proposed Rule?

    Today's notice proposes standards for controlling emissions of HAP 
from hazardous waste combustors. Hazardous waste combustors comprise 
several categories of sources that burn hazardous waste: incinerators, 
cement kilns, lightweight aggregate kilns, boilers and hydrochloric 
acid production furnaces. We call incinerators, cement kilns, and 
lightweight aggregate kilns Phase I sources because we have already 
promulgated standards for those source categories. We call boilers and 
hydrochloric acid production furnaces Phase II sources because we 
intended to promulgate MACT standards for those source categories after 
promulgating MACT standards for Phase I sources. The regulatory 
background of Phase I and Phase II source categories is discussed 
below.
1. Phase I Source Categories
    Phase I combustor sources are regulated under the Resource 
Conservation and Recovery Act (RCRA), which establishes a ``cradle-to-
grave'' regulatory structure overseeing the safe treatment, storage, 
and disposal of hazardous waste. We issued RCRA rules to control air 
emissions from incinerators in 1981, 40 CFR parts 264 and 265, subpart 
O, and from cement kilns and lightweight aggregate kilns that burn 
hazardous waste in 1991, 40 CFR part 266, subpart H. These rules rely 
generally on risk-based standards to achieve the RCRA protectiveness 
mandate.
    The Phase I source categories are also subject to standards under 
section 112(d) of the Clean Air Act. We promulgated standards for Phase 
I sources on September 30, 1999 (64 FR 52828). This final rule is 
referred to as the Phase I rule or 1999 final rule. These emission 
standards created a technology-based national cap for hazardous air 
pollutant emissions from the combustion of hazardous waste in these 
devices. The rule regulates emissions of numerous hazardous air 
pollutants: dioxin/furans, other toxic organics (through surrogates), 
mercury, other toxic metals (both directly and through a surrogate), 
and hydrogen chloride and chlorine gas. Where necessary, section 
3005(c)(3) of RCRA provides the authority to impose additional 
conditions in a RCRA permit to protect human health and the 
environment.
    A number of parties, representing interests of both industrial 
sources and of the environmental community, sought judicial review of 
the Phase I rule. On July 24, 2001, the United States Court of Appeals 
for the District of Columbia Circuit (the Court) granted portions of 
the Sierra Club's petition for review and vacated the challenged 
portions of the standards. Cement Kiln Recycling Coalition v. EPA, 255 
F. 3d 855 (D.C. Cir. 2001). The Court held that EPA had not 
demonstrated that its calculation of MACT floors met the statutory 
requirement of being no less stringent than (1) the average emission 
limitation achieved by the best performing 12 percent of existing 
sources and (2) the emission control achieved in practice by the best 
controlled similar source for new sources. 255 F.3d at 861, 865-66. As 
a remedy, the Court, after declining to rule on most of the issues 
presented in the industry petitions for review, vacated the 
``challenged regulations,'' stating that: ``[W]e have chosen not to 
reach the bulk of industry petitioners' claims, and leaving the 
regulations in place during remand would ignore petitioners' 
potentially meritorious challenges.'' Id. at 872. Examples of the 
specific challenges the Court indicated might have merit were 
provisions relating to compliance during start up/shut down and 
malfunction events, including emergency safety vent openings, the 
dioxin/furan standard for lightweight aggregate kilns, and the 
semivolatile metal standard for cement kilns. Id. However, the Court 
stated, ``[b]ecause this decision leaves EPA without standards 
regulating [hazardous waste combustor] emissions, EPA (or any of the 
parties to this proceeding) may file a motion to delay issuance of the 
mandate to request either that the current standards remain in place or 
that EPA be allowed reasonable time to develop interim standards.'' Id.
    Acting on this invitation, all parties moved the Court jointly to 
stay the issuance of its mandate for four months to allow EPA time to 
develop interim standards, which would replace the vacated standards 
temporarily, until final standards consistent with the Court's mandate 
are promulgated. The interim standards were published on February 13, 
2002 (67 FR 6792). EPA did not justify or characterize these standards 
as conforming to MACT, but rather as an interim measure to prevent the 
adverse environmental and other consequences that would result from the 
regulatory gap resulting from no standards being in place. Id. at 6795-
96.
    The motion also indicates that EPA will issue final standards which 
comply

[[Page 21203]]

with the Court's opinion by June 14, 2005, and it indicates that EPA 
and Petitioner Sierra Club intend to enter into a settlement agreement 
requiring us to promulgate final rules by that date, and that date be 
judicially enforceable. EPA and Sierra Club entered into that 
settlement agreement on March 4, 2002.
    The joint motion also details other actions we agreed to take, 
including issuing a one-year extension to the September 30, 2002, 
compliance date (66 FR 63313, December 6, 2001), and promulgating 
several of the compliance and implementation amendments to the rule 
which we proposed on July 3, 2001 (66 FR 35126). These final amendments 
were published on February 14, 2002 (67 FR 6968).
2. Phase II Source Categories
    Phase II combustors--boilers and hydrochloric acid production 
furnaces--are also regulated under the Resource Conservation and 
Recovery Act (RCRA) pursuant to 40 CFR part 266, subpart H, and (for 
reasons discussed below) are also subject to the MACT standard setting 
process in section 112(d) of the CAA. We delayed promulgating MACT 
standards for these source categories pending reevaluation of the MACT 
standard setting methodology following the Court's decision to vacate 
the standards for the Phase I source categories. We have also entered 
into a judicially enforceable consent decree with Sierra Club which 
requires EPA to promulgate MACT standards for the Phase II sources by 
June 14, 2005--the same date that (for independent reasons) is required 
for the replacement standards for Phase I sources.

C. What Is the Statutory Authority for This Standard?

    Section 112 of the Clean Air Act requires that the EPA promulgate 
regulations requiring the control of HAP emissions from major and 
certain area sources. The control of HAP is achieved through 
promulgation of emission standards under sections 112(d) and (in a 
second round of standard setting) (f) and, in appropriate 
circumstances, work practice standards under section 112(h).
    EPA's initial list of categories of major and area sources of HAP 
selected for regulation in accordance with section 112(c) of the Act 
was published in the Federal Register on July 16, 1992 (57 FR 31576). 
Incinerators, cement kilns, lightweight aggregate kilns, industrial/
commercial/institutional boilers and process heaters, and hydrochloric 
acid production furnaces are among the listed 174 categories of 
sources. The listing was based on the Administrator's determination 
that they may reasonably be anticipated to emit several of the 188 
listed HAP in quantities sufficient to designate them as major sources.

D. What Is the Relationship Between the Proposed Rule and Other MACT 
Combustion Rules?

    The proposed amendments to the subpart EEE, part 63, standards for 
hazardous waste combustors would apply to the source categories that 
are currently subject to that subpart--incinerators, cement kilns, and 
lightweight aggregate kilns that burn hazardous waste. Today's proposed 
rule, however, would also amend subpart EEE to establish MACT standards 
for the Phase II source categories--those boilers and hydrochloric acid 
production furnaces that burn hazardous waste.
    Generally speaking, you are an affected source pursuant to subpart 
EEE if you combust, or have previously combusted, hazardous waste in an 
incinerator, cement kiln, lightweight aggregate kiln, boiler, or 
hydrochloric acid production furnace. You continue to be an affected 
source until you cease burning hazardous waste and initiate closure 
requirements pursuant to RCRA. See Sec.  63.1200(b). If you never 
previously combusted hazardous waste, or have ceased burning hazardous 
waste and initiated RCRA closure requirements, you are not subject to 
subpart EEE. Rather, EPA has promulgated or proposed separate MACT 
standards for sources that do not burn hazardous waste within the 
following source categories: commercial and industrial solid waste 
incinerators (40 CFR part 60, subparts CCCC and DDDD); Portland cement 
manufacturing facilities (40 CFR part 63, subpart LLL); industrial/
commercial/institutional boilers and process heaters (40 CFR part 63, 
proposed subpart DDDDD); and hydrochloric acid production facilities 
(40 CFR part 63, subpart NNNNN). In addition, EPA considered whether to 
establish MACT standards for lightweight aggregate manufacturing 
facilities that do not burn hazardous waste, and determined that they 
are not major sources of HAP emissions. Thus, EPA has not established 
MACT standards for lightweight aggregate manufacturing facilities that 
do not burn hazardous waste.
    Note that non-stack emissions points are not regulated under 
subpart EEE.\1\ Emissions attributable to storage and handling of 
hazardous waste prior to combustion (i.e., emissions from tanks, 
containers, equipment, and process vents) would continue to be 
regulated pursuant to either RCRA subpart AA, BB, and CC or an 
applicable MACT that applies to the before-mentioned material handling 
devices. Emissions unrelated to the hazardous waste operations may be 
regulated pursuant to other MACT rulemakings. For example, Portland 
cement manufacturing facilities that combust hazardous waste are 
subject to both subpart EEE and subpart LLL, and hydrochloric acid 
production facilities that combust hazardous waste may be subject to 
both subpart EEE and subpart NNNNN.\2\ In these instances subpart EEE 
controls HAP emissions from the cement kiln and hydrochloric acid 
production furnace stack, while subparts LLL and NNNNN would control 
HAP emissions from other operations that are not directly related to 
the combustion of hazardous waste (e.g., clinker cooler emissions for 
cement production facilities, and hydrochloric acid product 
transportation and storage for hydrochloric acid production 
facilities).
---------------------------------------------------------------------------

    \1\ Note, however, that fugitive emissions attributable to the 
combustion of hazardous waste from the combustion device are 
regulated pursuant to subpart EEE.
    \2\ Hydrochloric acid production furnaces that combust hazardous 
waste would also be affected sources subject to subpart NNNNN if 
they produce a liquid acid product that contains greater than 30% 
hydrochloric acid.
---------------------------------------------------------------------------

    Note that if you temporarily cease burning hazardous waste for any 
reason, you remain an affected source and are still subject to the 
applicable Subpart EEE requirements. However, even as an affected 
source, the proposed emission standards or operating limits derived 
from the hazardous waste combustors do not apply if: (1) Hazardous 
waste is not in the combustion chamber and you elect to comply with 
other MACT (or CAA section 129) standards that otherwise would be 
applicable if you were not burning hazardous waste, e.g., the 
nonhazardous waste burning Portland Cement Kiln MACT (subpart LLL); or 
(2) you are in a startup, shutdown, or malfunction mode of operation.

E. What Are the Health Effects Associated With Pollutants Emitted by 
Hazardous Waste Combustors?

    Today's proposed rule protects air quality and promotes the public 
health by reducing the emissions of some of the HAP listed in section 
112(b)(1) of the CAA. Emissions data collected in the development of 
this proposed rule show that metals, particulate matter, hydrogen 
chloride and chlorine gas, dioxins and furans, and other organic 
compounds are emitted from hazardous waste combustors. The HAP that 
would

[[Page 21204]]

be controlled with this rule are associated with a variety of adverse 
health affects. These adverse health effects include chronic health 
disorders (e.g., irritation of the lung, skin, and mucus membranes and 
effects on the blood, digestive tract, kidneys, and central nervous 
system), and acute health disorders (e.g., lung irritation and 
congestion, alimentary effects such as nausea and vomiting, and effects 
on the central nervous system). Provided below are brief descriptions 
of risks associated with HAP that are emitted from hazardous waste 
combustors. Note that a more detailed discussion of the risks 
associated with these emissions is included in Part Four.
Antimony
    Antimony occurs at very low levels in the environment, both in the 
soils and foods. Higher concentrations, however, are found at antimony 
processing sites, and in their hazardous wastes. The most common 
industrial use of antimony is as a fire retardant in the form of 
antimony trioxide. Chronic occupational exposure to antimony (generally 
antimony trioxide) is most commonly associated with ``antimony 
pneumoconiosis,'' a condition involving fibrosis and scarring of the 
lung tissues. Studies have shown that antimony accumulates in the lung 
and is retained for long periods of time. Effects are not limited to 
the lungs, however, and myocardial effects (effects on the heart 
muscle) and related effects (e.g., increased blood pressure, altered 
EKG readings) are among the best-characterized human health effects 
associated with antimony exposure. Reproductive effects (increased 
incidence of spontaneous abortions and higher rates of premature 
deliveries) have been observed in female workers exposed in antimony 
processing facilities. Similar effects on the heart, lungs, and 
reproductive system have been observed in laboratory animals.
    EPA recently assessed the carcinogenicity of antimony and found the 
evidence for carcinogenicity to be weak, with conflicting evidence from 
inhalation studies with laboratory animals, equivocal data from the 
occupational studies, negative results from studies of oral exposures 
in laboratory animals, and little evidence of mutagenicity or 
genotoxicity.\3\ As a consequence, EPA concluded that insufficient data 
are available to adequately characterize the carcinogenicity of 
antimony and, accordingly, the carcinogenicity of antimony cannot be 
determined based on available information. However, IARC (International 
Agency for Research on Cancer) in an earlier evaluation, concluded that 
antimony trioxide is ``possibly carcinogenic to humans'' (Group 2B).
---------------------------------------------------------------------------

    \3\ See ``Evaluating the Carcinogenicity of Antimony,'' Risk 
Assessment Issue Paper (98-030/07-26-99), Superfund Technical 
Support Center, National Center for Environmental Assessment, July 
26, 1999.
---------------------------------------------------------------------------

Arsenic
    Acute (short-term) high-level inhalation exposure to arsenic dust 
or fumes has resulted in gastrointestinal effects (nausea, diarrhea, 
abdominal pain), and central and peripheral nervous system disorders. 
Chronic (long-term) inhalation exposure to inorganic arsenic in humans 
is associated with irritation of the skin and mucous membranes. Human 
data suggest a relationship between inhalation exposure of women 
working at or living near metal smelters and an increased risk of 
reproductive effects, such as spontaneous abortions. Inorganic arsenic 
exposure in humans by the inhalation route has been shown to be 
strongly associated with lung cancer, while ingestion or inorganic 
arsenic in humans has been linked to a form of skin cancer and also to 
bladder, liver, and lung cancer. EPA has classified inorganic arsenic 
as a Group A, human carcinogen.
Beryllium
    Beryllium is a hard, grayish metal naturally found in minerals, 
rocks, coal, soil, and volcanic dust. Beryllium dust enters the air 
from burning coal and oil. This beryllium dust will eventually settle 
over the land and water. It enters water from erosion of rocks and 
soil, and from industrial waste. Some beryllium compounds will dissolve 
in water, but most stick to particles and settle to the bottom. Most 
beryllium in soil does not dissolve in water and remains bound to soil. 
Beryllium does not accumulate in the food chain.
    Beryllium can be harmful if you breathe it. The effects depend on 
how much you are exposed to and for how long. If beryllium air levels 
are high enough, an acute condition can result. This condition 
resembles pneumonia and is called acute beryllium disease. Long-term 
exposure to beryllium can increase the risk of developing lung cancer.
Cadmium
    The acute (short-term) effects of cadmium inhalation in humans 
consist mainly of effects on the lung, such as pulmonary irritation. 
Chronic (long-term) inhalation or oral exposure to cadmium leads to a 
build-up of cadmium in the kidneys that can cause kidney disease. 
Cadmium has been shown to be a developmental toxicant in animals, 
resulting in fetal malformations and other effects, but no conclusive 
evidence exists in humans. An association between cadmium exposure and 
an increased risk of lung cancer has been reported from human studies, 
but these studies are inconclusive due to confounding factors. Animal 
studies have demonstrated an increase in lung cancer from long-term 
inhalation exposure to cadmium. EPA has classified cadmium as a Group 
B1, probable carcinogen.
Chlorine Gas
    Acute exposure to high levels of chlorine in humans can result in 
chest pain, vomiting, toxic pneumonitis, and pulmonary edema. At lower 
levels chlorine is a potent irritant to the eyes, the upper respiratory 
tract, and lungs. Chronic exposure to chlorine gas in workers has 
resulted in respiratory effects including eye and throat irritation and 
airflow obstruction. Animal studies have reported decreased body weight 
gain, eye and nose irritation, nonneoplastic nasal lesions, and 
respiratory epithelial hyperplasia from chronic inhalation exposure to 
chlorine. No information is available on the carcinogenic effects of 
chlorine in humans from inhalation exposure. We have not classified 
chlorine for potential carcinogenicity.
Chromium
    Chromium may be emitted in two forms, trivalent chromium (chromium 
III) or hexavalent chromium (chromium VI). The respiratory tract is the 
major target organ for chromium VI toxicity, for acute (short-term) and 
chronic (long-term) inhalation exposures. Shortness of breath, 
coughing, and wheezing have been reported from acute exposure to 
chromium VI, while perforations and ulcerations of the septum, 
bronchitis, decreased pulmonary function, pneumonia, and other 
respiratory effects have been noted from chronic exposure. Limited 
human studies suggest that chromium VI inhalation exposure may be 
associated with complications during pregnancy and childbirth, while 
animal studies have not reported reproductive effects from inhalation 
exposure to chromium VI. Human and animal studies have clearly 
established that inhaled chromium VI is a carcinogen, resulting in an 
increased risk of lung cancer. EPA has classified chromium VI as a 
Group A, human carcinogen.
    Chromium III is less toxic than chromium VI. The respiratory tract 
is also the major target organ for

[[Page 21205]]

chromium III toxicity, similar to chromium VI. Chromium III is an 
essential element in humans, with a daily intake of 50 to 200 
micrograms per day recommended for an adult. The body can detoxify some 
amount of chromium VI to chromium III. EPA has not classified chromium 
III with respect to carcinogenicity.
Cobalt
    Cobalt is a relatively rare metal that is produced primarily as a 
by-product during refining of other metals, primarily copper. Cobalt 
has been widely reported to cause respiratory effects in humans exposed 
by inhalation, including respiratory irritation, wheezing, asthma, and 
pneumonia. Cardiomyopathy (or damage to the heart muscle) has also been 
reported, although this effect is better known from oral exposure. 
Other effects of oral exposure in humans are polycythemia (an 
abnormally high number of red blood cells) and the blocking of uptake 
of iodine by the thyroid. In addition, cobalt is a sensitizer in humans 
by any route of exposure. Sensitized individuals may react to 
inhalation of cobalt by developing asthma or to ingestion or dermal 
contact with cobalt by developing dermatitis. Cobalt is a vital 
component of vitamin B12, though there is no evidence that 
intake of cobalt is ever limiting in the human diet.
    A number of epidemiological studies have found that exposures to 
cobalt are associated with an increased incidence of lung cancer in 
occupational settings. The International Agency for Research on Cancer 
(IARC, part of the World Health Organization) classifies cobalt and 
cobalt compounds as ``possibly carcinogenic to humans'' (Group 2B). The 
American Conference of Governmental Industrial Hygienists (ACGIH) has 
classified cobalt as a confirmed animal carcinogen with unknown 
relevance to humans (category A3). An EPA assessment concludes that 
under EPA's 1986 guidelines, cobalt would be classified as a probable 
human carcinogen (group B1) based on limited evidence of 
carcinogenicity in humans and sufficient evidence of carcinogenicity in 
animals, as evidenced by an increased incidence of alveolar/bronchiolar 
tumors in recent studies of both rats and mice. Under EPA's proposed 
cancer guidelines, cobalt is considered likely to be carcinogenic to 
humans.\4\
---------------------------------------------------------------------------

    \4\ See ``Derivation of a Provisional Carcinogenicity Assessment 
for Cobalt and Compounds,'' Risk Assessment Issue Paper (00-122/1-
15-02), Superfund Technical Support Center, National Center for 
Environmental Assessment, January 15, 2002.
---------------------------------------------------------------------------

Dioxins and Furans
    Exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) at 
levels 10 times or less above those modeled to approximate average 
background exposure have resulted in adverse non-cancer health effects 
in animals. These effects include changes in hormone systems, 
alterations in fetal development, reduced reproductive capacity, and 
immunosuppression. Effects that may be linked to dioxin and furan 
exposures at low dose in humans include changes in markers of early 
development and hormone levels. Dioxin and furan exposures are 
associated with altered liver function and lipid metabolism changes in 
activity of various liver enzymes, depression of the immune system, and 
endocrine and nervous system effects. EPA in its 1985 dioxin assessment 
classified 2,3,7,8-TCDD as a probable human carcinogen. The 
International Agency for Research on Cancer (IARC) concluded in 1997 
that the overall weight of the evidence was sufficient to characterize 
2,3,7,8-TCDD as a known human carcinogen.\5\ In 2001 the U.S. 
Department of Health and Human Services National Toxicology Program in 
their 9th Report on Carcinogens classified 2,3,7,8-TCDD as a known 
human carcinogen.\6\
---------------------------------------------------------------------------

    \5\ IARC (International Agency for Research on Cancer). (1997) 
IARC monographs on the evaluation of carcinogenic risks to humans. 
Vol. 69. Polychlorinated dibenzo-para-dioxins and polychlorinated 
dibenzofurans. Lyon, France.
    \6\ The U.S. Department of Health and Human Services, National 
Toxicology Program 9th Report on Carcinogens, Revised January 2001.
---------------------------------------------------------------------------

Hydrogen Chloride/Hydrochloric Acid
    Hydrogen chloride, also called hydrochloric acid, is corrosive to 
the eyes, skin, and mucous membranes. Acute (short-term) inhalation 
exposure may cause eye, nose, and respiratory tract irritation and 
inflammation and pulmonary edema in humans. Chronic (long-term) 
occupational exposure to hydrochloric acid has been reported to cause 
gastritis, bronchitis, and dermatitis in workers. Prolonged exposure to 
low concentrations may also cause dental discoloration and erosion. No 
information is available on the reproductive or developmental effects 
of hydrochloric acid in humans. In rats exposed to hydrochloric acid by 
inhalation, altered estrus cycles have been reported in females and 
increased fetal mortality and decreased fetal weight have been reported 
in offspring. EPA has not classified hydrochloric acid for 
carcinogenicity.
Lead
    Lead is a very toxic element, causing a variety of effects at low 
dose levels. Brain damage, kidney damage, and gastrointestinal distress 
may occur from acute (short-term) exposure to high levels of lead in 
humans. Chronic (long-term) exposure to lead in humans results in 
effects on the blood, central nervous system (CNS), blood pressure, and 
kidneys. Children are particularly sensitive to the chronic effects of 
lead, with slowed cognitive development, reduced growth and other 
effects reported. Reproductive effects, such as decreased sperm count 
in men and spontaneous abortions in women, have been associated with 
lead exposure. The developing fetus is at particular risk from maternal 
lead exposure, with low birth weight and slowed postnatal 
neurobehavioral development noted. Human studies are inconclusive 
regarding lead exposure and cancer, while animal studies have reported 
an increase in kidney cancer from lead exposure by the oral route. EPA 
has classified lead as a Group B2, probable human carcinogen.
Manganese
    Health effects in humans have been associated with both 
deficiencies and excess intakes of manganese. Chronic (long-term) 
exposure to low levels of manganese in the diet is considered to be 
nutritionally essential in humans, with a recommended daily allowance 
of 2 to 5 milligrams per day (mg/d). Chronic exposure to high levels of 
manganese by inhalation in humans results primarily in central nervous 
system (CNS) effects. Visual reaction time, hand steadiness, and eye-
hand coordination were affected in chronically-exposed workers. 
Manganism, characterized by feelings of weakness and lethargy, tremors, 
a mask-like face, and psychological disturbances, may result from 
chronic exposure to higher levels. Impotence and loss of libido have 
been noted in male workers afflicted with manganism attributed to 
inhalation exposures. EPA has classified manganese in Group D, not 
classifiable as to carcinogenicity in humans.
Mercury
    Mercury exists in three forms: elemental mercury, inorganic mercury 
compounds (primarily mercuric chloride), and organic mercury compounds 
(primarily methyl mercury). Each form exhibits different health 
effects. Various sources may release elemental or inorganic mercury; 
environmental methyl mercury is

[[Page 21206]]

typically formed by biological processes after mercury has precipitated 
from the air.
    Acute (short-term) exposure to high levels of elemental mercury in 
humans results in central nervous system (CNS) effects such as tremors, 
mood changes, and slowed sensory and motor nerve function. High 
inhalation exposures can also cause kidney damage and effects on the 
gastrointestinal tract and respiratory system. Chronic (long-term) 
exposure to elemental mercury in humans also affects the CNS, with 
effects such as increased excitability, irritability, excessive 
shyness, and tremors. EPA has not classified elemental mercury with 
respect to cancer.
    Acute exposure to inorganic mercury by the oral route may result in 
effects such as nausea, vomiting, and severe abdominal pain. The major 
effect from chronic exposure to inorganic mercury is kidney damage. 
Reproductive and developmental animal studies have reported effects 
such as alterations in testicular tissue, increased embryo resorption 
rates, and abnormalities of development. Mercuric chloride (an 
inorganic mercury compound) exposure has been shown to result in 
forestomach, thyroid, and renal tumors in experimental animals. EPA has 
classified mercuric chloride as a Group C, possible human carcinogen.
Nickel
    Nickel is a commonly used industrial metal, and is frequently 
associated with iron and copper ores. Contact dermatitis is the most 
common effect in humans from exposure to nickel, whether via 
inhalation, oral, or dermal exposure. Cases of nickel-contact 
dermatitis have been reported following occupational and non-
occupational exposure, with symptoms of itching of the fingers, wrists, 
and forearms. Many studies have also demonstrated dermal effects in 
sensitive humans from ingested nickel, invoking an eruption or 
worsening of eczema. Chronic inhalation exposure to nickel in humans 
results in direct respiratory effects, such as asthma due to primary 
irritation, or an allergic response and an increased risk of chronic 
respiratory tract infections.
    Animal studies have reported a variety of inflammatory effects on 
the lungs, as well as effects on the kidneys and immune system from 
inhalation exposure to nickel. Significant differences in inhalation 
toxicity among the various forms of nickel have been documented, with 
soluble nickel compounds being more toxic to the respiratory tract than 
less soluble compounds (e.g., nickel oxide). Animal studies have also 
reported effects on the respiratory and gastrointestinal systems, 
heart, blood, liver, kidney, and body weight from oral exposure to 
nickel, as well as to the fetus.
    EPA currently classifies nickel refinery dust and nickel subsulfide 
(a major component of nickel refinery dust) as class A human 
carcinogens based on increased risks of lung and nasal cancer in human 
epidemiological studies of occupational exposures to nickel refinery 
dust, increased tumor incidences in animals by several routes of 
administration in several animal species, and positive results in 
genotoxicity assays. More recently, a pair of inhalation studies 
performed under the auspices of the National Toxicology Program (NTP) 
of the National Institutes of Health concluded that there was no 
evidence of carcinogenic activity of soluble nickel salts in rats or 
mice and that there was some evidence of carcinogenic activity of 
nickel oxide in male and female rats based on increased incidence of 
alveolar/bronchiolar adenoma or carcinoma and increased incidence of 
benign or malignant pheochromocytoma (a tumor of the adrenal gland) and 
equivocal evidence in mice based on marginally increased incidence of 
alveolar/bronchiolar adenoma or carcinoma in females and no evidence in 
males. The Tenth Annual Report on Carcinogens classifies nickel 
compounds as ``known to be human carcinogens.'' \7\ This is consistent 
with the International Agency for Cancer Research (IARC) which 
classifies nickel compounds as Group 1 human carcinogens.
---------------------------------------------------------------------------

    \7\ Report on Carcinogens, Tenth Edition; U.S. Department of 
Health and Human Services, Public Health Service, National 
Toxicology Program, December 2002.
---------------------------------------------------------------------------

Organic HAP
    Organic HAPs include halogenated and nonhalogenated organic classes 
of compounds such as polycyclic aromatic hydrocarbons (PAHs) and 
polychlorinated biphenyls (PCBs). Both PAHs and PCBs are classified as 
potential human carcinogens, and are considered toxic, persistent and 
bioaccumulative. They include compounds such as benzene, methane, 
propane, chlorinated alkanes and alkenes, phenols and chlorinated 
aromatics. Adverse health effects of HAPs include damage to the immune 
system, as well as neurological, reproductive, developmental, 
respiratory and other health problems.
Particulate Matter \8\
---------------------------------------------------------------------------

    \8\ The discussion of PM effects is drawn from the executive 
summary of the ``Fourth External Review Draft of Air Quality 
Criteria for Particulate Matter,'' National Center for Environmental 
Assessment, Office of Research and Development, U.S. Environmental 
Protection Agency, EPA/600/P-99/002aD, June, 2003.
---------------------------------------------------------------------------

    Atmospheric PM is composed of sulfate, nitrate, ammonium, and other 
ions, elemental carbon, particle-bound water, a wide variety of organic 
compounds, and a large number of elements contained in various 
compounds, some of which originate from crustal materials and others 
from combustion sources. Combustion sources are the primary origin of 
trace metals found in fine particles in the atmosphere. Ambient PM can 
be of primary or secondary origin.\9\
---------------------------------------------------------------------------

    \9\ Secondary PM is not emitted directly but is formed in the 
atmosphere by gas phase or aqueous phase reactions of emissions of 
various precursor compounds.
---------------------------------------------------------------------------

    A large body of evidence exists from epidemiological studies that 
demonstrates a relationship between ambient particulate matter (PM) and 
mortality and morbidity in the general population and, when combined 
with evidence from other studies (e.g., clinical and animal studies), 
indicates that exposure to PM is a probable contributing cause to the 
adverse human health effects that have been observed. For example, many 
different studies report that increased cardiovascular and respiratory-
related mortality risks are significantly associated with various 
measures (both long-term and short-term) of ambient PM. Some studies 
suggest that a portion of the increased mortality may be associated 
with concurrent exposures to PM and other criteria pollutants, such as 
SO2. Much evidence exists of positive associations between 
ambient PM concentrations and increased respiratory-related hospital 
admissions, emergency room, and other medical visits. Additional 
findings implicate PM as likely associated with an increased occurrence 
of chronic bronchitis and a contributing factor in the exacerbation of 
asthmatic conditions. Recent reports from prospective cohort studies of 
long-term ambient PM exposures provide substantial evidence of an 
association between increased risk of lung cancer and PM, especially 
exposure to fine PM or its components.
    PM has other effects, beyond the health effects to human beings. 
The major effect of atmospheric PM on ecosystems is indirect and occurs 
through the deposition of nitrates and sulfates and the acidifying 
effects of the associated hydrogen ions contained in

[[Page 21207]]

wet and dry deposition.\10\ Acidification of surface waters can have 
long-term adverse effects on aquatic ecosystems, including effects on 
fish populations, macro invertebrates, species richness, and 
zooplankton abundance. In the soil environment, acid deposition has the 
potential to inhibit nutrient uptake, alter the ecological processes of 
energy flow and nutrient cycling, change ecosystem structure, and 
affect ecosystem biodiversity. In addition, ambient fine particles are 
well known as the major cause of visibility impairment. Visibility 
impairment (or haziness) is widespread in the U.S. and is greatest in 
the eastern United States and southern California. In addition, PM 
exerts important effects on materials, such as soiling, corrosion, and 
degradation of surfaces, and accelerates weathering of man-made and 
natural materials.
---------------------------------------------------------------------------

    \10\ Nitrates and sulfates in PM are derived primarily from 
emissions of SOX and NOX.
---------------------------------------------------------------------------

    A large body of evidence exists from epidemiological studies that 
demonstrates a relationship between ambient particulate matter (PM) and 
mortality and morbidity in the general population and, when combined 
with evidence from other studies (e.g., clinical and animal studies), 
indicates that exposure to PM is a probable contributing cause to the 
adverse human health effects that have been observed. For example, many 
different studies report that increased cardiovascular and respiratory-
related mortality risks are significantly associated with various 
measures (both long-term and short-term) of ambient PM. Some studies 
suggest that a portion of the increased mortality may be associated 
with concurrent exposures to PM and other criteria pollutants, such as 
SO2. Much evidence exists of positive associations between 
ambient PM concentrations and increased respiratory-related hospital 
admissions, emergency room, and other medical visits. Additional 
findings implicate PM as likely associated with an increased occurrence 
of chronic bronchitis and a contributing factor in the exacerbation of 
asthmatic conditions. Recent reports from prospective cohort studies of 
long-term ambient PM exposures provide substantial evidence of an 
association between increased risk of lung cancer and PM, especially 
exposure to fine PM or its components.
    PM has other effects, beyond the health effects to human beings. 
The major effect of atmospheric PM on ecosystems is indirect and occurs 
through the deposition of nitrates and sulfates and the acidifying 
effects of the associated hydrogen ions contained in wet and dry 
deposition.\11\ Acidification of surface waters can have long-term 
adverse effects on aquatic ecosystems, including effects on fish 
populations, macro invertebrates, species richness, and zooplankton 
abundance. In the soil environment, acid deposition has the potential 
to inhibit nutrient uptake, alter the ecological processes of energy 
flow and nutrient cycling, change ecosystem structure, and affect 
ecosystem biodiversity. In addition, ambient fine particles are well 
known as the major cause of visibility impairment. Visibility 
impairment (or haziness) is widespread in the U.S. and is greatest in 
the eastern United States and southern California. In addition, PM 
exerts important effects on materials, such as soiling, corrosion, and 
degradation of surfaces, and accelerates weathering of man-made and 
natural materials.
---------------------------------------------------------------------------

    \11\ Nitrates and sulfates in PM are derived primarily from 
emissions of SOX and NOX.
---------------------------------------------------------------------------

Selenium
    Selenium occurs naturally in soils, is associated with copper 
refining, and several industrial processes, and has been used in 
pesticides. It is an essential element and bioaccumulates in certain 
plant species, and has been associated with toxic effects in livestock 
(blind staggers syndrome). Soils containing high levels of selenium 
(seleniferous soils can lead to high concentration of selenium in 
certain plants, and pose a hazard to livestock and other species. 
Bioaccumulation and magnification of selenium has also been observed in 
aquatic organisms and has been shown to be toxic to piscivorous fish. 
In humans, selenium partitions to the kidneys and liver, and is 
excreted through the urine and feces. Selenium intoxication in humans 
causes a syndrome known as selenosis. The condition is characterized by 
chronic dermatitis, fatigue, anorexia, gastroenteritis, hepatic 
degeneration, enlarged spleen and increased concentrations of Se in the 
hair and nails. Clinical signs of selenosis include a characteristic 
``garlic odor'' of excess selenium excretion in the breath and urine, 
thickened and brittle nails, hair and nail loss, lowered hemoglobin 
levels, mottled teeth, skin lesions and CNS abnormalities (peripheral 
anesthesia, acroparesthesia and pain in the extremities). Aquatic birds 
are extremely sensitive to selenium; toxic effects include 
teratogenesis. Based on available data, both aquatic birds and aquatic 
mammals are sensitive ecological receptors.

II. Summary of the Proposed Rule

A. What Source Categories Are Affected by the Proposed Rule?

1. Incinerators That Burn Hazardous Waste
    A hazardous waste burning incinerator is defined under Sec.  
63.1201(a) as a device that meets the definition of an incinerator in 
40 CFR part 260.10 and that burns hazardous waste at any time. 
Hazardous waste incinerators are currently subject to the emission 
standards of part 63, subpart EEE.\12\ Hazardous waste incinerator 
design types include rotary kilns, liquid injection incinerators, 
fluidized bed incinerators, and fixed hearth incinerators. Most 
incinerators have air pollution control equipment to capture 
particulate matter (and nonvolatile metals) and scrubbing equipment for 
the capture of acid gases. At least four incinerators are equipped with 
activated carbon injection systems or carbon beds to control dioxin/
furan emissions (as well as other HAP emissions).
---------------------------------------------------------------------------

    \12\ Incinerators that burn hazardous waste will also remain 
subject to the RCRA hazardous waste incinerator emission limitations 
pursuant to Sec.  264 subpart O until they demonstrate compliance 
with the interim MACT standards and remove the emission limitations 
from their RCRA permit. See Sec.  270.42 appendix I, section a.8 and 
introductory paragraph to Sec.  270.62.
---------------------------------------------------------------------------

    Incinerators can be further classified as either commercial or 
onsite. Commercial incinerators accept and treat, for a tipping fee, 
wastes that have been generated off-site. The purpose of commercial 
incinerators is to generate profit from treating hazardous wastes. On-
site facilities treat only wastes that have been generated at the 
facility to avoid the costs of off-site treatment. In 2003, there were 
approximately 107 hazardous waste incinerators in operation, 15 of 
which were commercial facilities, the remaining being on-site 
facilities.
2. Cement Kilns That Burn Hazardous Waste
    A hazardous waste burning cement kiln is defined under Sec.  
63.1201(a). Cement kilns that burn hazardous waste are currently 
subject to the emission standards of part 63, subpart EEE.\13\ Cement 
kilns are long, cylindrical, slightly inclined rotating furnaces that 
are lined with refractory brick to protect the steel shell and retain 
heat within the

[[Page 21208]]

kiln. Cement kilns are designed to calcine, or expel carbon dioxide by 
roasting, a blend of raw materials such as limestone, shale, clay, or 
sand to produce Portland cement. The raw materials enter the kiln at 
the elevated end, and the combustion fuels generally are introduced 
into the lower end of the kiln where the clinker product is discharged. 
The materials are continuously and slowly moved to the lower end by 
rotation of the kiln. As they move down the kiln, the raw materials are 
changed to cementitious minerals as a result of increased temperatures 
within the kiln.
---------------------------------------------------------------------------

    \13\ Cement kilns that burn hazardous waste will also remain 
subject to the RCRA Boilers and Industrial Furnace emission 
limitations pursuant to Sec.  266 subpart H until they demonstrate 
compliance with the interim MACT standards and remove the emission 
limitations from their RCRA permit. See Sec.  270.42 appendix I, 
section a.8 and introductory paragraph to Sec.  270.66.
---------------------------------------------------------------------------

    Portland cement is a fine powder, usually gray in color, that 
consists of a mixture of minerals comprising primarily calcium 
silicates, aluminates, and aluminoferrites, to which small amounts of 
gypsum have been added during the finish grinding operations. Portland 
cement is the key ingredient in Portland cement concrete, which is used 
in almost all construction applications.
    Cement kilns covered by this proposal burn hazardous waste-derived 
fuels to replace some or all of normal fossil fuels, typically coal. 
Most kilns burn liquid waste; however, cement kilns also may burn 
solids and small containers containing viscous or solid hazardous waste 
fuels. The annual hazardous waste fuel replacement rate varies 
considerably across sources from approximately 25 to 85 percent.
    In 2003, there were 14 Portland cement plants in nine states 
operating a total of 25 hazardous waste burning kilns. All cement kilns 
use either bag houses or electrostatic precipitators to control 
particulate matter emissions.
3. Lightweight Aggregate Kilns That Burn Hazardous Waste
    A hazardous waste burning lightweight aggregate kiln is defined 
under Sec.  63.1201(a). Lightweight aggregate kilns that burn hazardous 
waste are currently subject to the emission standards of part 63, 
subpart EEE.\14\ Raw materials such as shale, clay, and slate are 
crushed and introduced at the upper end of the rotary kiln. In passing 
through the kiln, the materials reach temperatures of 1,900-2,100 [deg] 
F. Heat is provided by a burner at the lower end of the kiln where the 
product is discharged. As the raw material is heated, it melts into a 
semi-plastic state and begins to generate gases that serve as the 
bloating or expanding agent. As temperatures reach their maximum, the 
semi-plastic 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. Lightweight 
aggregate kilns are designed to expand the raw material by thermal 
processing into a coarse aggregate used in the production of 
lightweight concrete products such as concrete block, structural 
concrete, and pavement.
---------------------------------------------------------------------------

    \14\ Lightweight aggregate kilns that burn hazardous waste will 
also remain subject to the RCRA Boilers and Industrial Furnace 
emission limitations pursuant to Sec.  266 subpart H until they 
demonstrate compliance with the interim MACT standards and remove 
the emission limitations from their RCRA permit. See Sec.  270.42 
appendix I, section a.8 and introductory paragraph to Sec.  270.66.
---------------------------------------------------------------------------

    The lightweight aggregate kilns affected by this proposal burn 
hazardous waste-derived fuels to replace some or all of normal fossil 
fuels. Two of the facilities burn only liquid hazardous wastes, while 
the third facility burns both liquid and solid wastes. The annual 
hazardous waste fuel replacement rate is 100 percent.
    In 2003, there were three lightweight aggregate kiln facilities in 
two states operating a total of seven hazardous waste-fired kilns. All 
lightweight aggregate kilns use baghouses to control particulate matter 
and one facility also uses a venturi scrubber to control acid gas 
emissions.
4. Boilers That Burn Hazardous Waste
    Boilers that burn hazardous waste are currently regulated under 
RCRA at part 266, subpart H. We propose to use the RCRA definition of 
boiler under 40 CFR 260.10 for purposes of today's rulemaking for 
simplicity and continuity. This definition includes industrial, 
commercial, and institutional boilers as well as thermal units known in 
industry as process heaters. We propose to subcategorize boilers based 
on the type of fuel that is burned, which would result in separate 
emission standards for solid fuel-fired boilers and liquid fuel-fired 
boilers. We discuss subcategorization options in more detail in Part 
Two, Section II.
    Boilers are typically described by either their design or type of 
fuel burned. Hazardous waste burning boilers comprise two basic 
different boiler designs--watertube and firetube. The choice of which 
design to use depends on factors such as the desired steam quality, 
thermal efficiency, size, economics, fuel type, and responsiveness. 
Watertube boilers are those that flow the water through tubes running 
the length of the boiler. The hot combustion gas surrounds these tubes, 
causing the water inside to get hot. Most hazardous waste burning 
boilers use this design. Watertube boilers can also burn a variety of 
fuel types including coal, oil, gas, wood, and municipal or industrial 
wastes. Firetube boilers are similar to watertube type, except the 
placement of the water and combustion gas is reversed. Here the hot 
combustion gas flows through the tubes, while the water surrounds the 
tubes. This design does have some disadvantages, however, in that they 
work well with only gas and liquid fuels.
    Process heaters are similar to boilers (as conventionally defined), 
except they heat a fluid other than water. This fluid is often an oil 
or some other fluid with more suitable heating properties. Process 
heaters are often used in circumstances where the amount of heat needed 
is greater than what can be delivered by steam. For the purposes of 
this rulemaking and consistent with current RCRA regulations, process 
heaters would be classified as boilers.
    Descriptions of liquid and solid fuel-fired boilers that burn 
hazardous waste are provided below.
    a. Liquid Fuel-Fired Boilers. A liquid fuel-fired boiler is a 
device that meets the definition of a boiler under 40 CFR 260.10 and 
that burns any combination of liquid and gas fuels, but no solids. See 
proposed definition in Sec.  63.1201(a). A liquid fuel is defined as a 
fuel that is pumpable (e.g., liquid wastes, sludges, or slurries). Most 
liquid hazardous waste burning boilers co-fire natural gas, fuel oil, 
or process gases to achieve the proper combustion temperatures and a 
consistent steam supply.
    There are approximately 104 liquid fuel-fired boilers that burn 
hazardous waste, 85 of which have not installed back-end air pollution 
control equipment. The rest of the liquid boilers use either a wet 
scrubber, electrostatic precipitator, or fabric filter. These boilers 
co-fire liquid hazardous waste with either natural gas or heating oil 
at heat input rates of 10% to 100%.
    b. Solid Fuel-Fired Boilers. A solid fuel-fired boiler is a device 
that meets the definition of a boiler under 40 CFR 260.10 and that 
burns solid fuels, including both pulverized and stoker coal.\15\ See 
proposed definition in Sec.  63.1201(a). Boilers that co-fire solid 
fuel with liquid or gaseous fuels are solid fuel-fired boilers.
---------------------------------------------------------------------------

    \15\ Please note that the RCRA definition of boiler includes 
devices defined under part 63 as boilers and process heaters.
---------------------------------------------------------------------------

    There are 12 solid fuel-fired boilers that burn hazardous waste. 
These boilers co-fire liquid hazardous waste with coal at heat input 
rates of 6% to 33%. Nine of these boilers are stoker-fired, and three 
burn pulverized coal. Two boilers are equipped with fabric filters to 
control particulate matter and

[[Page 21209]]

metals, and 10 are equipped with electrostatic precipitators.
5. Hydrochloric Acid Production Furnaces That Process Hazardous Waste
    Hydrochloric acid production furnaces that burn hazardous waste are 
currently regulated under RCRA at part 266, subpart H. We propose to 
use the RCRA definition of hydrochloric acid production furnace under 
40 CFR 260.10 for purposes of today's rulemaking for simplicity and 
continuity. See proposed definition in Sec.  63.1201(a).
    Hydrochloric acid production furnaces burn chlorinated hazardous 
wastes to make an aqueous hydrochloric acid for on-site use as an 
ingredient in a manufacturing process. The hazardous waste feedstocks 
have a chlorine content of over 20% by weight. The hydrochloric acid 
produced by burning the chlorinated byproducts dissolves in the 
scrubber water to produce an acid product containing hydrochloric acid 
greater than 3% by weight. There are 17 hazardous waste burning 
hydrochloric acid production furnaces currently in operation.
    Chlorine-bearing feedstreams, wastes, and auxiliary fuels (usually 
natural gas) are burned in these hydrochloric acid production furnaces 
in a refractory lined chamber similar to a liquid waste incinerator 
chamber. Combustion is maintained at a high temperature, with adequate 
excess hydrogen to ensure the conversion of chlorine in the feedstreams 
to hydrogen chloride in the combustion gases. Many furnaces also have 
waste heat boilers, similar to those used by some incinerators, to 
recover heat and return it to the production process. Others use a 
water spray quench to cool the combustion gases.
    The cooled combustion flue gas is routed to an acid recovery 
system, consisting of multiple wet scrubbing absorption units. These 
units are usually packed tower or film tray scrubbers which operate 
with an acidic scrubbing solution. The scrubbing solution is recycled 
to concentrate the acid until it reaches the desired concentration 
level, at which point it is recovered for use as a valuable product. A 
final polishing scrubber, operated with a caustic liquid solution, is 
used to control emissions of hydrogen chloride and chlorine gas.

B. What HAP Are Emitted?

    Incinerators, cement kilns, lightweight aggregate kilns, and 
hydrochloric acid production furnaces that burn hazardous waste can 
emit high levels of dioxin/furans depending on the design and operation 
of the emission control equipment, and, for incinerators, whether a 
waste heat recovery boiler is used. Our data base shows that boilers 
that burn hazardous waste generally do not emit high levels of dioxin/
furans.
    All hazardous waste combustors can emit high levels of other 
organic HAP if they are not designed, operated, and maintained to 
operate under good combustion conditions.
    Hazardous waste combustors can also emit high levels of metal HAP, 
depending on the level of metals in the waste feed and the design and 
operation of air emissions control equipment. Hydrochloric acid 
production furnaces, however, generally feed and emit low levels of 
metal HAP.
    Hazardous waste combustors can also emit high levels of particulate 
matter, except that hydrochloric acid production furnaces generally 
feed wastes with low ash content and emit low levels of particulate 
matter.\16\ The majority of particulate matter emissions from hazardous 
waste combustors is in the form of fine particulate (i.e., 50% or more 
of the particulate matter emitted is 2.5 microns in diameter or 
less).\17\ Particulate emissions from incinerators and liquid fuel-
fired boilers depend on the ash content of the waste feed and the 
design and operation of air emission control equipment. Particulate 
emissions from cement kilns and lightweight aggregate kilns are not 
significantly affected by the ash content of the hazardous waste fuel 
because uncontrolled particulate emissions are attributable primarily 
to raw material entrained in the combustion gas. Thus, particulate 
emissions from kilns depend on operating conditions that affect 
entrainment of raw material, and the design and operation of the 
emission control equipment.
---------------------------------------------------------------------------

    \16\ Emissions of particulate matter are of interest because 
metal HAP, except notably for mercury, are in the particulate form 
in stack gas. Thus, controlling particulate matter controls metal 
HAP.
    \17\ Particulate size distributions are somewhat dependent on 
the type of combustor. See USEPA ``Draft Technical Support Document 
for HWC MACT Replacement Standards, Volume V: Emission Estimates and 
Engineering Costs,'' March 2004, Chapter 7 for more information.
---------------------------------------------------------------------------

C. Does Today's Proposed Rule Apply to My Source?

    The following sources that burn hazardous waste are considered to 
be affected sources subject to today's proposed rule: Incinerators, 
cement kilns, lightweight aggregate kilns, boilers, and hydrochloric 
acid production furnaces. Affected sources do not include: (1) Sources 
exempt from regulation under 40 CFR part 266, subpart H, because the 
only hazardous waste they burn is listed under 40 CFR 266.100(c); (2) 
research, development, and demonstration sources exempt under Sec.  
63.1200(b); and (3) boilers exempt from regulation under 40 CFR part 
266, subpart H, because they meet the definition of small quantity 
burner under 40 CFR 266.108. See Sec.  63.1200(b).
    Affected sources also do not include emission points that are 
unrelated to the combustion of hazardous waste (e.g., cement kiln 
clinker cooler stack emissions, hydrochloric acid production facility 
emissions originating from product or waste storage tanks and transfer 
operations, etc.). This is because subpart EEE only controls HAP 
emission points that are directly related to the combustion of 
hazardous waste. Under separate rulemakings, the Agency has or will 
establish MACT standards, where warranted, to control HAP emissions 
from non-hazardous waste related emission points.
    Hazardous waste combustors are affected sources irrespective of 
whether they are major sources or area sources. As discussed in Part 
Two, Section I.A, we are proposing to subject area sources of boilers 
and hydrochloric acid production furnaces to the major source MACT 
standards for mercury, dioxin/furans, carbon monoxide/hydrocarbons, and 
destruction and removal efficiency pursuant to section 112(c)(6). As 
promulgated in the 1999 rule, both area source and major source 
incinerators, cement kilns, and lightweight aggregate kilns will 
continue to be subject to the full suite of Subpart EEE emission 
standards.

D. What Emissions Limitations Must I Meet?

    Under today's proposal, you would have to comply with the emission 
limits in Tables 1 and 2. Note that these emission limitations are 
discussed in greater detail for each source category (and subcategory) 
in Part Two, Section VII thru XII. Note also that we are proposing 
several alternative emission standards: (1) You may elect to comply 
with an alternative to the particulate matter standard for incinerators 
and liquid fuel-fired boilers that would limit emissions of total metal 
HAP; and (2) you may elect to comply with an alternative to the total 
chlorine standard applicable to all source categories, except 
hydrochloric acid production furnaces, under which you may establish 
site-specific, risk-based emission limits for hydrogen chloride and 
chlorine gas based on national

[[Page 21210]]

exposure standards. These alternative standards are discussed in Part 
Two, Section XVIII and Section XIII, respectively.

                                                    Table 1.--Proposed Standards for Existing Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                       Hydrochloric acid
                                     Incinerators        Cement kilns         Lightweight      Solid fuel-fired    Liquid fuel-fired      production
                                                                            aggregate kilns       boilers \1\         boilers \1\        furnaces \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dioxin/Furans ( ng TEQ/dscm)....  0.28 for dry APCD   0.20 or 0.40 +      0.40..............  CO or THC standard  0.40 for dry APCD   0.40
                                   and WHB sources;    400[deg]F at APCD                       as a surrogate.     sources; CO or HC
                                   \6\ 0.40 for        inlet.                                                      standard as
                                   others.                                                                         surrogate for
                                                                                                                   others.
Mercury.........................  130 ug/dscm.......  64 ug/dscm \2\....  67 ug/dscm \2\....  10 ug/dscm........  3.7E-6 lb/MMBtu 2,  Total chlorine
                                                                                                                   5.                  standard as
                                                                                                                                       surrogate
Particulate Matter..............  0.015 gr/dscf \8\.  0.028 gr/dscf.....  0.025 gr/dscf.....  0.030 gr/dscf \8\.  0.032 gr/dscf \8\.  Total chlorine
                                                                                                                                       standard as
                                                                                                                                       surrogate
Semivolatile Metals (lead +       59 ug/dscm........  4.0E-4 lbs/MMBtu    3.1E-4 lb/MMBtu     170 ug/dscm.......  1.1E-5 lb/MMBtu 2,  Total chlorine
 cadmium).                                             \5\.                \5\ and 250 ug/                         5.                  standard as
                                                                           dscm \3\.                                                   surrogate
Low Volatile Metals (arsenic +    84 ug/dscm........  1.4E-5 lbs/MMBtu    9.5E-5 lbs/MMBtu    210 ug/dscm.......  1.1E-4 lb/MMBtu 4,  Total chlorine
 beryllium + chromium).                                \5\.                \5\ and 110 ug/                         5.                  standard as
                                                                           dscm \3\.                                                   surrogate
Total Chlorine (hydrogen          1.5 ppmv \7\......  110 ppmv \7\......  600 ppmv \7\......  440 ppmv \7\......  2.5E-2 lb/MMBtu     14 ppmv or
 chloride + chlorine gas).                                                                                         \5, 7\.             99.9927% system
                                                                                                                                       removal
                                                                                                                                       efficiency
Carbon Monoxide (CO) or           100 ppmv CO or 10   See Part Two,       100 ppmv CO or 20                 (2) 100 ppmv CO or 10 ppmv HWC
 Hydrocarbons HWC.                 ppmv HWC.           Section VIII.       ppmv HWC.
Destruction and Removal            99.99% for each principal organic hazardous pollutant. For sources burning hazardous wastes F020, F021, F022, F023,
 Efficiency (DRE).                 F026, or F027, however, 99.9999% for each principal organic hazardous pollutant.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Particulate matter, semivolatile metal, low volatile, and total chlorine standards apply to major sources only for solid fuel-fired boilers, liquid
  fuel-fired boilers, and hydrochloric acid production furnaces.
\2\ Standard is based on normal emissions data.
\3\ Sources must comply with both the thermal emissions and emission concentration standards.
\4\ Low volatile metal standard for liquid fuel-fired boilers is for chromium only. Arsenic and beryllium are not included in the low volatile metal
  total for liquid fuel-fired boilers.
\5\ Standards are expressed as mass of pollutant contributed by hazardous waste per million Btu contributed by the hazardous waste.
\6\ APCD denotes ``air pollution control device'', WHB denotes ``waste heat boiler''.
\7\ Sources may elect to comply with site-specific, risk-based emission limits for hydrogen chloride and chlorine gas based on national exposure
  standards. See Part Two, Section XIII.
\8\ Sources may elect to comply with an alternative to the particulate matter standard. See Part Two, Section XVIII.


                                                      Table 2.--Proposed Standards for New Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                       Hydrochloric acid
                                     Incinerators        Cement kilns         Lightweight     Solid fuel boilers      Liquid fuel         production
                                                                            aggregate kilns           \1\             boilers \1\        furnaces \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dioxin/Furans ( ng TEQ/dscm)....  0.11 for dry APCD   0.20 or 0.40 +      0.40..............  Carbon monoxide     0.015 or 400[deg]F  0.40
                                   or WHBs \5\; 0.2    400[deg]F at                            (CO) or             at the inlet to
                                   for others.         inlet to                                hydrocarbon (HC)    particulate
                                                       particulate                             as a surrogate.     matter control
                                                       matter control                                              device for dry
                                                       device.                                                     APCD; CO or HC
                                                                                                                   standard as
                                                                                                                   surrogate for
                                                                                                                   others.
Mercury.........................  8 ug/dscm.........  35 ug/dscm \2\....  67 ug/dscm \2\....  10 ug/dscm........  3.8E-7 lb/MMBtu 2,  Tcl as surrogate
                                                                                                                   4.
Particulate matter..............  0.00070 gr/dscf     0.0058 gr/dscf....  0.0099 gr/dscf....  0.015 gr/dscf \7\.  0.0076 gr/dscf \7\  TCL as surrogate
                                   \7\.
Semivolatile Metals (lead +       6.5 ug/dscm.......  6.2E-5 lb/MMBtu     2.4E-5 lb/MMBtu     170 ug/dscm.......  4.3E-6 lb/MMBtu 2,  TCL as surrogate
 cadmium).                                             \4\.                \4\.                                    4.
Low Volatile Metals (arsenic +    8.9 ug/dscm.......  1.4E-5 lb/MMBtu     3.2E-5 lb/MMBtu     190 ug/dscm.......  3.6E-5 lb/MMBtu in  TCL as surrogate
 beryllium + chromium).                                \4\.                \4\.                                    HW 3, 4.
Total Chlorine (Hydrogen          0.18 ppmv \6\.....  78 ppmv \6\.......  600 ppmv \6\......  73 ppmv \6\.......  7.2E-4 lb/MMBtu 4,  1.2 ppmv or
 chloride + chlorine gas).                                                                                         6.                  99.99937% SRE

[[Page 21211]]

 
Carbon monoxide CO or             100 ppmv (CO) or    See Part Two,       100 ppmv CO or 20                    100 ppmv CO or 10 ppmv HWC
 Hydrocarbons (HWC).               10 ppmv HWC.        Section VIII.       ppmv HWC.
Destruction and Removal           99.99% for each principal organic hazardous pollutant. For sources burning hazardous wastes F020, F021, F022, F023,
 Efficiency.                       F026, or F027, however, 99.9999% for each principal organic hazardous pollutant.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Particulate matter, semivolatile metal, low volatile metal, and total chlorine standards apply to major sources only for solid fuel-fired boilers,
  liquid fuel-fired boilers, and hydrochloric acid production furnaces.
\2\ Standard is based on normal emissions data.
\3\ Low volatile metal standard for liquid fuel-fired boilers is for chromium only. Arsenic and beryllium are not included in the low volatile metal
  total for liquid fuel-fired boilers.
\4\ Standards are expressed as mass of pollutant contributed by hazardous waste per million Btu contributed by the hazardous waste.
\5\ APCD denotes ``air pollution control device'', WHB denotes ``waste heat boiler''.
\6\ Sources may elect to comply with site-specific, risk-based emission limits for hydrogen chloride and chlorine gas based on national exposure
  standards. See Part Two, Section XIII.
\7\ Sources may elect to comply with an alternative to the particulate matter standard. See Part Two, Section XVIII.

E. What Are the Testing and Initial Compliance Requirements?

    We are proposing testing and initial compliance requirements for 
solid fuel-fired boilers, liquid fuel-fired boilers and hydrochloric 
acid production furnaces that are identical to those that are 
applicable to incinerators, cement kilns, and lightweight aggregate 
kilns already in place at Sec. Sec.  63.1206, 63.1207, and 63.1208. 
Please note also that in Part Three of today's preamble we request 
comment on, or propose revisions to, several testing and initial 
compliance requirements. Any amendments to the testing and compliance 
requirements that we promulgate as a result of those discussions would 
be applicable to all hazardous waste combustors.
    In addition, we are proposing to revise the existing initial 
compliance requirements for incinerators, cement kilns, and lightweight 
aggregate kilns. Under the proposed revision, owners and operators of 
incinerators, cement kilns, and lightweight aggregate kilns would be 
required to conduct the initial comprehensive performance test to 
document compliance with the replacement standards proposed today 
(Sec. Sec.  63.1219, 63.1220, and 63.1221) within 12 months of the 
compliance date. Owners and operators of solid fuel-fired boilers, 
liquid fuel-fired boilers and hydrochloric acid production furnaces 
would be required to conduct an initial comprehensive performance test 
within six months of the compliance date, and periodic comprehensive 
performance tests every five years. The purpose of the comprehensive 
performance test is to document compliance with the emission standards, 
document that continuous monitoring systems meet performance 
requirements, and establish limits on operating parameters that would 
be monitored by continuous monitoring systems.
    Owners and operators of liquid fuel-fired boilers equipped with a 
dry air pollution control device and hydrochloric acid production 
furnaces would be required to conduct a dioxin/furan confirmatory 
performance test 2.5 years after each comprehensive performance test 
(i.e., midway between comprehensive performance tests). The purpose of 
the dioxin/furan confirmatory performance test is to document 
compliance with the dioxin/furan standard when operating within the 
range of normal operations. Owners and operators of solid fuel-fired 
boilers, and liquid fuel-fired boilers that are not subject to a 
numerical dioxin/furan emission standard (i.e., liquid fuel-fired 
boilers other than those equipped with an electrostatic precipitator or 
fabric filter), would be required to conduct a one-time dioxin/furan 
test to enable the Agency to evaluate the effectiveness of the carbon 
monoxide/hydrocarbon standard and destruction and removal efficiency 
standard in controlling dioxin/furan emissions for those sources. The 
Agency would use those emissions data when reevaluating the MACT 
standards under section 112(d)(6) and when determining whether to 
develop residual risk standards for these sources pursuant to CAA 
section 112(f)(2).
    Owners and operators of solid fuel-fired boilers, liquid fuel-fired 
boilers and hydrochloric acid production furnaces would be required to 
use the following stack test methods to document compliance: (1) Method 
29 for mercury, semivolatile metals, and low volatile metals; and (2) 
Method 26A for hydrogen chloride and chlorine gas; (3) either Method 
0023A or Method 23 for dioxin/furans; and (4) either Method 5 or 5i for 
particulate matter.
    The following is a proposed time-line for testing and initial 
compliance requirements for owners and operators of solid fuel-fired 
boilers, liquid fuel-fired boilers and hydrochloric acid production 
furnaces: (1) The compliance date is three years from publication of 
the final rule; (2) you must place in the operating record a 
Documentation of Compliance by the compliance date identifying that the 
operating parameter limits you have determined using available 
information will ensure compliance with the emission standards; (3) you 
must commence the initial comprehensive performance test within six 
months of the compliance date; (4) you must complete the initial 
comprehensive performance test within 60 days of commencing the test; 
and (5) you must submit a Notification of Compliance within 90 days of 
completing the test documenting compliance with emission standards and 
CMS requirements.

F. What Are the Continuous Compliance Requirements?

    We are proposing continuous compliance requirements for solid fuel-
fired boilers, liquid fuel-fired boilers and hydrochloric acid 
production furnaces that are identical to those already in place at 
Sec.  63.1209 and applicable to incinerators, cement kilns, and 
lightweight aggregate kilns. Please note, however, that in Part Three 
of today's preamble we request comment on, or propose revisions to, 
several continuous compliance requirements. Any amendments to the 
continuous compliance requirements that we promulgate as a result of 
those discussions would be applicable to all hazardous waste 
combustors.

[[Page 21212]]

    Owners and operators of solid fuel-fired boilers, liquid fuel-fired 
boilers and hydrochloric acid production furnaces would be required to 
use carbon monoxide or hydrocarbon continuous emissions monitors (as 
well as an oxygen continuous emissions monitor to correct the carbon 
monoxide or hydrocarbon values to 7% oxygen) to ensure compliance with 
the carbon monoxide or hydrocarbon emission limits.
    Owners and operators of solid fuel-fired boilers, liquid fuel-fired 
boilers and hydrochloric acid production furnaces would also be 
required to establish limits on the feedrate of metals, chlorine, and 
(for some source categories) ash, key combustor operating parameters, 
and key operating parameters of the control device based on operations 
during the comprehensive performance test. You must continuously 
monitor these parameters with continuous monitoring systems. See Part 
Two, Section XIV.C for a discussion of the specific parameters for 
which you must establish limits.

G. What Are the Notification, Recordkeeping, and Reporting 
Requirements?

    We are proposing notification, recordkeeping, and reporting 
requirements for solid fuel-fired boilers, liquid fuel-fired boilers 
and hydrochloric acid production furnaces that are identical to those 
already in place at Sec. Sec.  63.1210 and 63.1211 and applicable to 
incinerators, cement kilns, and lightweight aggregate kilns. Please 
note, however, that we are proposing a new requirement applicable to 
all hazardous waste combustors that would require you to submit a 
Notification of Intent to Comply and a Compliance Progress Report. See 
Part Two, Section XVI.B.
    The proposed notification, recordkeeping, and reporting 
requirements are summarized in Part Two, Section XVI.

Part Two: Rationale for the Proposed Rule

I. How Did EPA Determine Which Hazardous Waste Combustion Sources Would 
Be Regulated

A. How Are Area Sources Regulated?

    We are proposing to subject area source boilers and hydrochloric 
acid production furnaces to the major source MACT standards for 
mercury, dioxin/furan, carbon monoxide/hydrocarbons, and destruction 
and removal efficiency pursuant to section 112(c)(6).\18\ Both area 
source and major source incinerators, cement kilns, and lightweight 
aggregate kilns will continue to be subject to the full suite of 
Subpart EEE emission standards.\19\
---------------------------------------------------------------------------

    \18\ We are using carbon monoxide or hydrocarbons and 
destruction and removal efficiency as surrogates for control of 
polycyclic organic matter emissions.
    \19\ In support of the 1999 Final Rule, EPA determined 
incinerators, cement kilns, and lightweight aggregate kilns that are 
area sources can emit HAP at levels that pose a hazard to human 
health and the environment. Accordingly, EPA subjected area sources 
within those source categories to the same emission standards that 
apply to major sources. See 64 FR at 52837-38.
---------------------------------------------------------------------------

    Section 112(c)(6) of the CAA requires EPA to list and promulgate 
section 112(d)(2) or (d)(4) standards (i.e., standards reflecting MACT) 
for categories and subcategories of sources emitting seven specific 
pollutants. Four of those listed pollutants are emitted by boilers and 
hydrochloric acid production furnaces: mercury, 2,3,7,8-
tetrachlorodibenzofuran, 2,3,7,8-tetrachlorodibenzo-p-dioxin, and 
polycyclic organic matter. EPA must assure that source categories 
accounting for not less than 90 percent of the aggregated emissions of 
each enumerated pollutant are subject to MACT standards. Congress 
singled out the pollutants in section 112(c)(6) as being of ``specific 
concern'' not just because of their toxicity but because of their 
propensity to cause substantial harm to human health and the 
environment via indirect exposure pathways (i.e., from the air through 
other media, such as water, soil, food uptake, etc.). Furthermore, 
these pollutants have exhibited special potential to bioaccumulate, 
causing pervasive environmental harm in biota and, ultimately, human 
health risks.
    We estimate that approximately 1,800 pounds of mercury are emitted 
annually in aggregate from hazardous waste burning boilers in the 
United States.\20\ Also, we estimate that hazardous waste burning 
boilers and hydrochloric acid production furnaces emit in aggregate 
approximately 1.1 and 1.6 grams TEQ per year of dioxin/furan, 
respectively. The Agency has already counted on the control of these 
pollutants from area sources in the industrial/commercial/institutional 
boiler source category when we accounted for at least 90 percent of the 
emissions of these hazardous air pollutants as being subject to 
standards under section 112(c)(6). See 63 FR 17838; April 10, 1998. 
Therefore, we are proposing to subject boiler and hydrochloric acid 
furnace area sources to the major source MACT standards for mercury, 
dioxin/furan, carbon monoxide/hydrocarbons, and destruction and removal 
efficiency pursuant to section 112(c)(6).
---------------------------------------------------------------------------

    \20\ See USEPA ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume V: Emission Estimates and Engineering 
Costs,'' March, 2004, Chapter 3.
---------------------------------------------------------------------------

    We are proposing that only major source boilers and hydrochloric 
acid furnaces would be subject to the full suite of subpart EEE 
emission standards we propose today. Section 112(c)(3) of the CAA 
requires us to subject area sources to the full suite of standards 
applicable to major sources if we find ``a threat of adverse effects to 
human health or the environment'' that warrants such action. We cannot 
make this finding for area source boilers and halogen acid production 
furnaces.\21\ Consequently, area sources in these categories would be 
subject to the MACT standards for mercury, dioxin/furan, carbon 
monoxide/hydrocarbons, and destruction and removal efficiency standards 
only to control the HAP listed under section 112(c)(6). RCRA standards 
under Part 266, Subpart H for particulate matter, metals other than 
mercury, and hydrogen chloride and chlorine gas would continue to apply 
to these area sources unless an area source elects to comply with the 
major source standards in lieu of the RCRA standards. See proposed 
Sec.  266.100(b)(3) and the proposed revisions to Sec. Sec.  270.22 and 
270.66.
---------------------------------------------------------------------------

    \21\ We believe that two or fewer boilers are area sources. We 
do not believe any hydrochloric acid production furnaces are area 
sources.
---------------------------------------------------------------------------

B. What Hazardous Waste Combustors Are Not Covered by This Proposal?

1. Small Quantity Burners
    Boilers that are exempt from the RCRA hazardous waste-burning 
boilers rule under 40 CFR 266.108 because they burn small quantities of 
hazardous waste fuel would also be exempt from today's proposed rule. 
Those boilers would be subject, however, to the MACT standards the 
Agency has proposed for industrial/commercial/institutional boilers. 
See 68 FR 1660, January 13, 2003.
    The type and concentration of HAP emissions from boilers that co-
fire small quantities of hazardous waste fuel with other fuels under 
Sec.  266.108 should be characterized more by the metals and chlorine 
levels in the primary fuels and the effect of combustion conditions on 
the primary fuels than by the composition and other characteristics of 
the hazardous waste fuel. Under Sec.  266.108, boilers that burn small 
quantities of hazardous waste fuel cannot fire hazardous waste at any 
time at a rate greater than 1 percent of the

[[Page 21213]]

total fuel requirements for the boiler. In addition, a boiler with a 
stack height of 20 meters or less cannot fire more than 84 gallons of 
hazardous waste fuel a month, which would equate to an average firing 
rate of 0.5 quarts per hour. Finally, the hazardous waste fuel must 
have a heating value of 5,000 Btu/lb to ensure it is a bonafide fuel, 
and cannot contain hazardous wastes that are listed because they 
contain chlorinated dioxins/furans. Given these restrictions, we 
believe that HAP emissions are not substantially related to the 
hazardous waste fuels these boilers burn. Thus, these boilers are more 
appropriately regulated under the MACT standards proposed at part 63, 
subpart DDDDD, than the MACT standards proposed today for hazardous 
waste combustors.
    Boilers that burn small quantities of hazardous waste fuel under 
Sec.  266.108 would become subject to part 63, subpart DDDDD, three 
years after publication of the final rule for hazardous waste 
combustors (i.e., the rules we are proposing today). Subpart DDDDD 
exempts ``a boiler or process heater required to have a permit under 
section 3005 of the Solid Waste Disposal Act [i.e., RCRA] or covered by 
40 CFR part 63, subpart EEE (e.g., hazardous waste combustors).'' See 
40 CFR 63.7491(d). Boilers that burn small quantities of hazardous 
waste fuel under Sec.  266.108 are exempt from the substantive emission 
standards of part 266, subpart H, and the permit requirements of 40 CFR 
part 270 (establishing RCRA permit requirements). In addition, owners 
and operators of such boilers would not know whether they are covered 
by part 63, subpart EEE, until we promulgate the final rule for 
hazardous waste combustors. Thus, it is appropriate to require that 
these boilers begin complying with subpart DDDDD three years after we 
publish the final rule for hazardous waste combustors.
2. Sources Exempt From RCRA Emission Regulation Under 40 CFR Part 
266.100(c)
    Consistent with the Phase I Hazardous Waste Combustor MACT rule 
promulgated in 1999, we would not subject boilers and hydrochloric acid 
production furnaces to today's proposed requirements if the only 
hazardous waste combusted is exempt from regulation pursuant to Sec.  
266.100(c), including certain types of used oil, landfill gas, and 
otherwise exempt or excluded waste. This is appropriate because HAP 
emissions from sources that qualify for this exemption would not be 
significantly impacted by the combustion of hazardous waste. Thus, 
emissions from these sources would be more appropriately regulated by 
other promulgated MACT standards that specifically address emissions 
from these sources.
3. Research, Development, and Demonstration Sources
    Consistent with the Phase I Hazardous Waste Combustor MACT rule 
promulgated in 1999, we would not subject boilers and hydrochloric acid 
production furnaces that are research, development, and demonstration 
sources to today's proposed requirements. We explained at promulgation 
of the Phase I MACT standards that the hazardous waste combustor 
emission standards may not be appropriate for research, development, 
and demonstration sources because of their typically intermittent 
operations and small size. See 64 FR at 52839. Given that emissions 
from these sources are addressed under RCRA on case-by-case basis 
pursuant to Sec.  270.65, we continue to believe this is appropriate, 
and we are today proposing the same exemption for boilers and 
hydrochloric acid production furnaces.

C. How Would Sulfuric Acid Regeneration Facilities Be Regulated?

    Sulfuric acid regeneration facilities burn spent sulfuric acid and 
sulfur-bearing hazardous wastes or hazardous waste fuel to produce 
sulfuric acid and are subject to 40 CFR part 266, subpart H, (i.e., the 
RCRA Boiler and Industrial Furnace Rule) as a listed industrial 
furnace. We are not proposing MACT standards for these sources because 
EPA did not list sulfuric acid regeneration facilities as a category of 
major sources of HAP emissions. See 57 FR 31576 (July 16, 1992). We 
obtained emissions and other data on these sources and confirmed that 
they emit very low levels of HAP.\22\ Accordingly, these combustors 
will remain subject to RCRA regulations under part 266, subpart H.
---------------------------------------------------------------------------

    \22\ See U.S. EPA, ``Draft Technical Support Document for HWC 
MACT Replacement Standards, Volume II: HWC Emissions Data Base,'' 
March 2004.
---------------------------------------------------------------------------

II. What Subcategorization Considerations Did EPA Evaluate?

    CAA section 112(d)(1) allows us to distinguish amongst classes, 
types, and sizes of sources within a category when establishing floor 
levels. Subcategorization typically reflects ``differences in 
manufacturing process, emission characteristics, or technical 
feasibility.'' See 67 FR 78058. A classic example, provided in the 
legislative history to CAA 112(d), is of a different process leading to 
different emissions and different types of control strategies--the 
specific example being Soderberg and prebaked anode primary aluminum 
processes. See ``A Legislative History of the Clean Air Act Amendments 
of 1990,'' vol. 1 at 1138-39 (floor debates on Conference Report). If 
we determine, for instance, that a given source category includes 
sources that are designed differently such that the type or 
concentration of HAP emissions are different we may subcategorize these 
sources and issue separate standards.
    We have determined that it is appropriate to subcategorize sources 
that combust hazardous waste from those sources that do not. EPA 
published an initial list of categories of major and area sources of 
HAP selected for regulation in accordance with section 112(c) of the 
Act on July 16, 1992 (57 FR 31576). Hazardous waste incineration, 
Portland cement manufacturing, clay products manufacturing (including 
lightweight aggregate manufacturing), industrial/commercial/
institutional boilers and process heaters, and hydrochloric acid 
production are among the listed 174 categories of sources. Although 
some cement kilns, lightweight aggregate kilns, boilers and process 
heaters, and hydrochloric acid production furnaces burn hazardous 
waste, EPA did not list hazardous waste burning sources as separate 
source categories. Nonetheless, we generally believe that hazardous 
waste combustion sources can emit different types or concentrations of 
HAP emissions because hazardous waste combustors: (1) Have different 
fuel HAP concentrations; (2) use different control techniques (e.g., 
feed control); and (3) have a different regulatory history given that 
their toxic emissions were regulated pursuant to RCRA standards. As a 
result, we believe it is appropriate to subcategorize each source 
category listed above to define sources that burn hazardous waste as a 
separate classes of combustors. We also assessed if further subdividing 
each class of hazardous waste burning combustors is warranted using 
both engineering judgement and statistical analysis. In our proposed 
approach, we first use engineering information and principles to 
identify potential subcategorization options. We then determine if 
there is a statistical difference in the emission characteristics 
between these options. See Part Two, Section VI.C for a discussion of 
this statistical analysis. Finally, we review the results of the 
statistical analysis to determine whether they are an appropriate basis 
for

[[Page 21214]]

subcategorization.\23\ We describe below the subcategorization options 
we considered for each source category.
---------------------------------------------------------------------------

    \23\ For example, although the statistical analysis may find a 
significant difference in emission levels between potential 
subcategories, the emission levels may be more a function of the 
emission control equipment rather than a function of the design and 
operation of the combustors within the subcategories. If differences 
in emission levels are attributable to use of different emission 
control devices, and if there is nothing inherent in the design or 
operation of sources in both subcategories that would preclude 
applicability of those control devices, subcategorization would not 
be warranted.
---------------------------------------------------------------------------

A. What Subcategorization Options Did We Consider for Incinerators?

    We considered whether to propose separate standards for three 
hazardous waste incinerator subcategory options. First, we assessed 
whether government-owned incinerator facilities had different emission 
characteristics when compared to non-government facilities for the 
mercury, semivolatile metal, low volatile metal, particulate matter, 
and total chlorine floors. After evaluating the data, we determined 
that emission characteristics from these two subcategories are not 
statistically different, and, therefore are not proposing separate 
emission standards.
    Second, we assessed whether liquid injection incinerators emitted 
significantly different levels of metals and particulate matter 
compared to incinerators that feed solid wastes (e.g., rotary kilns, 
fluid bed units, and hearth fired units). We define liquid injection 
units as those incinerators that exclusively feed pumpable waste 
streams and solid feed units as those that feed a combination of liquid 
and solid wastes. We determined that emissions of metal HAP from these 
potential subcategories are not statistically different.\24\ We, 
therefore, are not proposing separate emission standards for metal HAP. 
The statistical analysis for particulate matter shows that emissions 
from liquid feed injection incinerators are higher than emissions from 
solid feed injection units. However, we believe that separate standards 
for particulate matter are not warranted because the difference in 
emissions was more a factor of the types of back-end air pollution 
devices used by the sources rather than incinerator design. We would 
expect particulate emissions to be potentially higher for solid feed 
units, not lower, because solid feed units have higher ash feedrates 
and air pollution control device inlet particulate matter loadings. 
Therefore, we must conclude that the difference is the product of less 
effective back-end air pollution control.
---------------------------------------------------------------------------

    \24\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards'', 
March 2004, Chapter 4.
---------------------------------------------------------------------------

    Third, we assessed whether incinerators equipped with dry air 
pollution control devices and/or waste heat boilers have different 
dioxin/furan emission characteristics when compared to other sources, 
i.e., sources with either wet air pollution control or no air pollution 
control devices. Our statistical analysis determined that dioxin/furan 
emissions from sources equipped with waste heat boilers and/or dry air 
pollution control devices are higher.\25\ We believe use of wet air 
pollution control systems (and use of no air pollution control system) 
can result in different dioxin/furan emission characteristics because 
they have different post-combustion particle residence times and 
temperature profiles, which can affect dioxin/furan surface catalyzed 
formation reaction rates. As a result, we believe that it is 
appropriate to subcategorize these different types of combustors.
---------------------------------------------------------------------------

    \25\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards'', 
March 2004, Chapter 4.
---------------------------------------------------------------------------

    Note that we do not subcategorize based on the type of air 
pollution control device used. See 69 FR 394 (January 5, 2004). Dioxin/
furan emission characteristics are unique in that they are not 
typically fed into the combustion device, but rather are formed in the 
combustor or post combustion within ductwork, a heat recovery boiler, 
or the air pollution control system. Wet and dry air pollution control 
systems are generally not considered to be dioxin/furan control systems 
because their primary function is to remove metals and/or total 
chlorine from the combustion gas. They generally do not remove dioxin/
furans from the incinerator flue gas unless they are used in tandem 
with carbon injection systems or carbon beds. (In contrast, carbon 
injection systems and carbon beds are considered to be dioxin/furan air 
pollution control systems). Thus, the differences in dioxin formation 
here reflect something more akin to a process difference resulting in 
different emission characteristics, rather than a difference in 
pollution-capture efficiencies among pollution control devices. We thus 
are not proposing to subcategorize based on whether a source is 
equipped with a dioxin/furan control system.
    We also considered whether to further subcategorize based on the 
presence of a waste heat boiler or dry air pollution control device. 
Our analysis determined that dioxin/furan emissions from incinerators 
with waste heat boilers are not statistically different from those 
equipped with dry air pollution control devices.\26\ We conclude that 
further subcategorization is not necessary. See Part Two, Section VII.A 
for more discussion on the proposed dioxin/furan standards for 
incinerators.
---------------------------------------------------------------------------

    \26\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards'', 
March 2004, Chapter 4.
---------------------------------------------------------------------------

B. What Subcategorization Options Did We Consider for Cement Kilns?

    We considered subdividing hazardous waste burning cement kilns by 
the clinker manufacturing process: wet process kilns without in-line 
raw mills versus preheater/precalciner kilns with in-line raw mills. 
All cement kilns that burn hazardous waste use one of these clinker 
manufacturing processes. Based on available emissions data, we 
evaluated design and operating features of each process to determine if 
the features could have a significant impact on emissions. For the 
reasons discussed below, we believe that subcategorization is not 
warranted.
    In the wet process, raw materials are ground, wetted, and fed into 
the kiln as a slurry. Twenty-two of the 25 cement kilns that burn 
hazardous waste use the wet process to manufacture clinker. In the 
preheater/precalciner kilns, raw materials are ground dry in a raw mill 
and fed into the kiln dry. The remaining three of the 25 cement kilns 
burning hazardous waste use preheater/precalciner kilns with in-line 
raw mills.
    Combustion gases and raw materials move in a counterflow direction 
inside a cement kiln for both processes. The kiln is inclined, and raw 
materials are fed into the upper end while fuels are typically fired 
into the lower end. Combustion gases move up the kiln counter to the 
flow of raw materials. The raw materials get progressively hotter as 
they travel down the length of the kiln. The raw materials begin to 
soften and fuse at temperatures between 2,250 and 2,700 [deg]F to form 
the clinker product.
    Wet process kilns are longer than the preheater/precalciner kilns 
in order to facilitate evaporation of the water from the slurried raw 
material. The preheater/precalciner kilns begin the calcining process--
heating of the limestone to drive off carbon dioxide to obtain lime 
(calcium oxide)--before the raw materials are fed into the kiln. This 
is accomplished by routing the flue gases from the kiln up through the 
preheater tower while the raw materials are passing down the preheater 
tower.

[[Page 21215]]

The heat of the flue gas is transferred to the raw material as they 
interact in the preheater tower. The precalciner is a secondary firing 
system--typically fired with coal--located at the base of the preheater 
tower.
    Though not necessary in a wet process kiln, a preheater/precalciner 
kiln uses an alkali bypass designed to divert a portion of the flue gas 
to remove problematic volatile constituents such as alkalies (potassium 
and sodium oxides), chlorides, and sulfur that, if not removed, can 
lead to operating problems. In addition, removal of the alkalies is 
necessary so that their concentrations are below maximum acceptable 
levels in the clinker. An alkali bypass diverts between 10-30% of the 
kiln off-gas before it reaches the lower cyclone stages of the 
preheater tower. Without use of a bypass, the high concentration of 
volatile constituents at the lower cyclone stage of the preheater tower 
would create operational problems. Bypass gases are quenched and sent 
to a dedicated particulate matter control device to capture and remove 
the volatile constituents.
    All preheater/precalciner kilns that burn hazardous waste use the 
hot flue gases to dry the raw materials as they are being ground in the 
in-line raw mill. Typically, the raw mill is operating or ``on'' 
approximately 85% of the time. The kilns with in-line raw mills must 
operate both in the ``on'' mode--gases are routed through the raw mill 
supporting raw material drying and preparation--and in the ``off'' 
mode--necessary down time for raw mill maintenance. Given that there 
are few preheater/precalciner cement kilns that burn hazardous waste, 
we had limited emissions data to evaluate to see if there was a 
significant difference in emissions. Moreover, we do not have any data 
from a preheater/precalciner kiln operating under similar operating 
conditions (e.g., metals and chlorine feed concentrations) both for the 
``on'' mode and ``off'' mode.
    We evaluated whether there was a significant difference in HAP 
emissions between wet process kilns without in-line raw mills versus 
preheater/precalciner kilns with in-line raw mills. We found a 
statistically significant difference in mercury emissions between wet 
process kilns and preheater/precalciner kilns in the ``off'' mode.\27\ 
But, we conclude that there is no significant difference in emissions 
of dioxin/furans, particulate matter, semivolatile metals, low volatile 
metals, and total chlorine between these types of kiln systems.\28\
---------------------------------------------------------------------------

    \27\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards'', 
March 2004, Chapter 4.
    \28\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume V: Emission Estimates and Engineering 
Costs'', March 2004, Chapter 4.
---------------------------------------------------------------------------

    For wet process cement kilns without in-line raw mills, mercury 
remains in the vapor phase at the typical operating temperatures in the 
kiln and particulate matter control equipment, and exits the kiln as 
volatile stack emissions with only a small fraction partitioning to the 
clinker or cement kiln dust. In the preheater/precalciner kilns with 
in-line raw mill, we believe that a significant portion of the 
volatilized mercury condenses on to the surfaces of the cooler raw 
material in the operating raw mill. The raw material with adsorbed 
mercury ends up in the raw material storage bin which will eventually 
be fed to the kiln and re-volatilized. During the periods that the in-
line raw mill is ``on'', mercury is effectively captured in the raw 
mill essentially establishing an internal recycle loop of mercury that 
builds-up within the system. Eventually, when the in-line raw mill 
switches to the ``off'' mode, the re-volatilized mercury exits the kiln 
as volatile stack emissions. Notwithstanding the apparent removal of 
mercury during periods that the in-line raw mill is ``on'' in a 
preheater/precalciner kiln, over time the mercury is emitted eventually 
as volatile stack emissions because system removal efficiencies for 
mercury are essentially zero. Thus, over a longer period of time (e.g., 
one month), the mass of mercury emitted by a wet process kiln without 
an in-line raw mill and a preheater/precalciner kiln with an in-line 
raw mill (assuming identical mercury-containing feedstreams) would be 
the same. However, at any given point in time, the stack gas 
concentration of mercury of the two types of kilns could be 
significantly different.
    As noted above, our data base shows a significant difference in 
mercury emissions between preheater/precalciner kilns when operating in 
the ``off'' mode and emissions both from wet process kilns and 
preheater/precalciner kilns in the ``on'' mode. In spite of this 
difference, we don't believe it is technically justified to 
subcategorize cement kilns for mercury.\29\
---------------------------------------------------------------------------

    \29\ We note that in the September 1999 final rule we 
established a provision that allows cement kilns operating in-line 
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. See Sec.  63.1204(d).
---------------------------------------------------------------------------

    In conclusion, we propose not to subcategorize the hazardous waste 
burning class of cement kilns by wet process kilns and preheater/
precalciner kilns with in-line raw mills.

C. What Subcategorization Options Did We Consider for Lightweight 
Aggregate Kilns?

    Following promulgation of the September 1999 Final Rule, Solite 
Corporation filed a Petition for Review challenging the total chlorine 
standard for new kilns. For new sources, the Clean Air Act states that 
the MACT floor cannot be ``less stringent than the emission control 
that is achieved by the best controlled similar source.'' Solite 
Corporation challenged the standard on the ground that Norlite 
Corporation, another hazardous waste-burning lightweight aggregate kiln 
source, should not be the best controlled similar source because they 
are designed to burn for purposes of treatment hazardous wastes 
containing high levels of chlorine and high mercury. Solite states that 
Norlite's superior emission control equipment is designed to control 
the chlorine and mercury in these wastes that are burned for treatment, 
rather than primarily as fuel for lightweight aggregate production. 
Thus, Solite states that Norlite's sources should be considered a 
separate class of lightweight aggregate kilns.
    Though we believe that subcategorizing by the concentrations of HAP 
in the hazardous waste is not appropriate, we considered subdividing 
hazardous waste burning lightweight aggregate kilns by the types of 
hazardous waste they combust: low Btu wastes with higher concentrations 
of chlorine and mercury and high Btu wastes with lower concentrations 
of chlorine and mercury. We believe, however, that separate emission 
standards for lightweight aggregate kilns based on the types of 
hazardous waste they burn are unnecessary because the floor levels 
would not differ significantly under either approach.
    Analysis of available total chlorine emissions from compliance 
testing indicates that the emissions are significantly different for 
sources burning hazardous waste with high levels of chlorine compared 
to sources burning wastes with much lower levels of chlorine. Total 
chorine emissions range from 14 to 116 ppmv for sources feeding higher 
concentrations of chlorine but using a venturi scrubber to control 
emissions and range from 500 to 2,400 ppmv for sources feeding waste 
with lower levels of chlorine and not using a wet scrubber. However, 
when we identify floor levels for these potential subcategories (both 
for existing and new sources), the calculated floor

[[Page 21216]]

level would be less stringent than the interim emission standard 
sources are currently achieving. Because all sources are achieving the 
more stringent interim standard, the interim standard becomes the 
default floor level. Therefore, subdividing would not affect the 
proposed floor level.
    We have compliance test mercury emissions data representing maximum 
emissions for only one source, and we have snap-shot mercury emissions 
data within the range of normal emissions for all sources. Snap-shot 
mercury emissions range from: (1) 11 to 20 ug/dscm for sources with the 
potential to feed higher concentrations of mercury because they use a 
venturi scrubber to control emissions; and (2) 1 to 47 ug/dscm for 
sources that typically feed lower mercury containing wastes and do not 
use a wet scrubber to control mercury. We performed a statistical test 
and confirmed that there is no statistically significant difference in 
the snap-shot mercury emissions between sources that have the potential 
to feed higher levels of mercury because they are equipped with a wet 
scrubber and with other sources. Therefore, it appears that 
subcategorization for mercury is not warranted.\30\
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    \30\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standard, Volume III: Selection of MACT Standards'', 
March 2004, Chapter 4.
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D. What Subcategorization Options Did We Consider for Boilers?

    We discuss below the rationale for proposing to subcategorize 
boilers by the physical form of the fuels they burn--solid fuel-fired 
boilers and liquid fuel-fired boilers. We also discuss further 
subcategorization options we considered for each of those subcategories 
and explain why we believe that further subcategorization is not 
warranted.
1. Subcategorization by Physical Form of Fuels Burned
    There are substantial design differences and emission 
characteristics among boilers that cofire hazardous waste primarily 
with coal versus oil or gas. Because of these differences, it is 
appropriate to subcategorize boilers by the physical form of the fuel 
burned. We note that the Agency has already proposed that industrial/
commercial/institutional boilers and process heaters that do not burn 
hazardous waste should be subcategorized by the physical form of fuels 
fired.\31\
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    \31\ See 68 FR at 1670 (January 13, 2003).
---------------------------------------------------------------------------

    Twelve boilers cofire hazardous waste with coal. These boilers are 
designed to handle high ash content solid fuels, including the 
relatively large quantities of boiler bottom ash and particulate matter 
that are entrained in the combustion gas. The coal also contributes to 
emissions of metal HAP. Approximately 104 boilers co-fire hazardous 
waste with natural gas or fuel oil. These units are not designed to 
handle the high ash loadings that are associated with coal-fired units, 
and the primary fuels for these boilers contribute little to HAP 
emissions. See ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume I: Description of Source Categories'' 
(Chapter 2.4) and ``Volume III: Selection of MACT Standards'' (Chapter 
4) for a discussion of the design differences between liquid and coal 
fuel-fired boilers.
    Because the type of primary fuel burned dictates the design of the 
boiler and emissions control systems, and can affect the concentration 
of HAP, it is appropriate to subcategorize boilers by the physical form 
of the fuel.
2. Subcategorization Considerations Among Solid Fuel Boilers
    We considered whether to subcategorize solid fuel-fired boilers to 
establish separate particulate matter standards. All 12 of the solid 
fuel-fired boilers co-fire hazardous waste with coal. Three of the 12 
boilers burn pulverized coal while the remaining nine are stoker-fired 
boilers. Pulverized coal-fired boilers have higher uncontrolled 
emissions than stoker-fired boilers because the coal is pulverized to a 
talcum powder consistency and burned in suspension. Stoker-fired 
boilers burn lump coal partially or totally on a grate. Thus, much more 
of the coal ash is entrained in the combustion gas for pulverized coal-
fired boilers than for stoker-fired boilers.
    Although the pulverized coal-fired boilers have higher uncontrolled 
particulate matter emissions (i.e., at the inlet to the emission 
control device), controlled emissions from the pulverized coal-fired 
boilers are not statistically different than emissions from the stoker-
fired boilers, primarily because all solid fuel-fired boilers are 
equipped with either a baghouse or electrostatic precipitator.\32\ 
Accordingly, we conclude that it is not appropriate to establish 
separate particulate matter standards for pulverized coal-fired boilers 
versus stoker-fired boilers. This is consistent with the proposal for 
industrial/institutional/commercial boilers and process heaters that do 
not burn hazardous waste.
---------------------------------------------------------------------------

    \32\ See USEPA ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards,'' 
March 2004, Chapter 4.
---------------------------------------------------------------------------

3. Subcategorization Considerations for Liquid Fuel Boilers
    We believe it is appropriate to combine liquid and gas fuel boilers 
into one subcategory because emissions from gas fuel boilers are within 
the range of emissions one finds from liquid fuel boilers. Also, most 
of the hazardous waste burning liquid fuel boilers, in fact, burn gas 
fossil fuels to supplement the liquid hazardous waste fuel. Even though 
there are no hazardous waste gas burning boilers currently in 
operation, today we propose to subject hazardous waste gas burning 
boilers that may begin operating in the future to the standards for 
liquid fuel-fired boilers. See proposed definition of liquid boiler in 
Sec.  63.2101(a).
    We also assessed whether liquid fuel-fired boilers equipped with 
dry air pollution control devices had different dioxin/furan emission 
characteristics when compared to other sources, i.e., sources with 
either wet air pollution control devices or no air pollution control 
device. Our statistical analysis indicated that dioxin/furan emissions 
from sources equipped with dry air pollution control devices are 
higher.\33\ We believe use of wet air pollution control systems (and 
use of no air pollution control system) can result in different dioxin/
furan emission characteristics because they have different post-
combustion particle residence times and temperature profiles, which can 
affect dioxin/furan surface catalyzed formation reaction rates. As a 
result, we believe that it is appropriate to have different 
subcategories for these different types of combustors. As discussed 
previously for incinerators in Part Two, Section II.A, the differences 
in dioxin formation here reflect something more akin to a process 
difference resulting in different emission characteristics, rather than 
a difference in pollution-capture efficiencies among pollution control 
devices. We thus are not subcategorizing based on whether a source is 
equipped with a dioxin/furan control system.
---------------------------------------------------------------------------

    \33\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards'', 
March 2004, Chapter 4.
---------------------------------------------------------------------------

E. What Subcategorization Options Did We Consider for Hydrochloric Acid 
Production Furnaces?

    Consistent with our incinerator subcategorization analysis (see 
Section A of this Part), we also considered whether to establish 
separate floor emission standards for dioxin/furans for

[[Page 21217]]

hydrochloric acid production furnaces equipped with waste heat recovery 
boilers versus those without boilers. As discussed below, we conclude 
that there is no significant statistical difference in dioxin/furan 
emissions between furnaces equipped with boilers and those without 
them. As a result we do not propose to have different subcategories for 
these sources.
    Ten of the 16 hydrochloric acid production furnaces are equipped 
with waste heat recovery boilers, and all hydrochloric acid production 
furnaces are equipped with wet scrubbers that quench the combustion gas 
immediately after it exits the furnace or boiler. We have dioxin/furan 
emissions data for eight of the ten furnaces with boilers. Two furnaces 
have low dioxin/furan emissions--approximately 0.1 ng TEQ/dscm, while 
the other six furnaces have emissions ranging from 0.5 to 6.8 ng TEQ/
dscm. We have dioxin/furan emissions data for five of the six furnaces 
without boilers. Dioxin/furan emissions for four furnaces are below 
0.15 ng TEQ/dscm. But, one furnace has dioxin/furan emissions of 1.7 ng 
TEQ/dscm.
    It appears that dioxin/furan emissions from hydrochloric acid 
production furnaces may not be governed by whether the furnace is 
equipped with a waste heat recovery boiler. We performed a statistical 
test and confirmed that there is no statistically significant 
difference in dioxin/furan emissions between furnaces equipped with 
boilers and those without boilers.\34\ Thus, we conclude that it is not 
appropriate to establish separate dioxin/furan emission standards for 
furnaces with boilers and those without boilers.
---------------------------------------------------------------------------

    \34\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards'', 
March 2004, Chapter 4.
---------------------------------------------------------------------------

III. What Data and Information Did EPA Consider To Establish the 
Proposed Standards?

    The proposed standards are based on our hazardous waste combustor 
data base. The data base contains general facility information, stack 
gas emissions data, combustor design information, composition and feed 
concentration data for the hazardous waste, fossil fuel, and raw 
materials, combustion unit operating conditions, and air pollution 
control device operating information. We gathered the emissions data 
and information from test reports submitted by hazardous waste 
combustor facilities to EPA Regional Offices or State agencies. Many of 
the test reports were prepared as part of the compliance demonstration 
process for the current RCRA standards, and may include results from 
trial burns, certification of compliance demonstrations, annual 
performance tests, mini-burns, and risk burns.

A. Data Base for Phase I Sources

    The current data base for Phase I sources contain test results for 
over 100 incinerators, 26 cement kilns, and 9 lightweight aggregate 
kilns. In many cases, especially for cement and lightweight aggregate 
kilns, the data base contain test reports from multiple testing 
campaigns. For example, our data base includes results for a cement 
kiln that conducted emissions testing for the years 1992, 1995, and 
2000.
    We first compiled a data base for hazardous waste burning 
incinerators, cement kilns, and lightweight aggregate kilns to support 
the proposed MACT standards in 1996 (61 FR 17358, April 19, 1996). 
Based on public comments, a revised Phase I data base was published for 
public comment (62 FR 960, January 7, 1997). The data base was again 
revised based on public comments, and we used this data base to develop 
the Phase I MACT standards promulgated in 1999 (64 FR 52828, September 
30, 1999).
    Following promulgation of the interim standards, we initiated a 
data collection effort in early 2002 to obtain additional test reports. 
The effort focused on obtaining test reports from sources for which we 
had no information, obtaining data from more recent testing, and 
updating the list of operating Phase I sources. Sources once identified 
as hazardous waste combustors, but that have since ceased operations as 
a hazardous waste combustor, were removed from the data base. This 
revised data base was noticed for public comment in July 2002 (67 FR 
44452, July 2, 2002) and updated based on public comments. See USEPA 
``Draft Technical Support Document for HWC MACT Replacement Standards, 
Volume II: HWC Emissions Data Base,'' March 2004, Appendix A for 
comments and responses.
    In comments on the data base notice, industry stakeholders question 
whether emissions data obtained for some sources are appropriate to use 
to identify MACT floor for today's proposed replacement standards. 
Stakeholders suggest that it is inappropriate to use emissions data 
from sources that tested after retrofitting their emission control 
systems to meet the emission standards promulgated in September 1999 
(and since vacated and replaced by the February 2002 Interim 
Standards). Stakeholders refer to this as MACT-on-MACT: establishing 
MACT floor based on sources that already upgraded to meet the 1999 
standards. Stakeholders identified emissions data from only 
approximately three of the Phase I sources (all incinerators) as being 
obtained after the source upgraded to meet the 1999 standards. None of 
these incinerator sources are consistently identified as a best 
performer when establishing the proposed MACT standards.
    Notwithstanding stakeholder concerns, we believe it is appropriate 
to consider all of the data collected in the 2002 effort.\35\ First, 
section 112(d)(3) states that floor standards for existing sources are 
to reflect the average emission achieved by the designated per cent of 
best performing sources ``for which the Administrator has emissions 
information'' (emphasis added). Second, the motivation for a source's 
performance is legally irrelevant in developing MACT floor levels. 
National Lime Ass'n v. EPA, 233 F. 3d at 640. In any case, it would be 
problematic to identify sources that upgraded their facilities (and 
reduced their emissions) for purposes of complying with the 1999 
standards versus for other purposes (e.g., normal replacement 
schedule). Moreover, the MACT-on-MACT formulation is not correct. 
Although the Interim Standards did result in reduction of emissions 
from many sources, those standards are not MACT standards, and do not 
purport to be. See February 13, 2002, Interim Standards Rulemaking, 67 
FR at 7693. Finally, we note that, although we were prepared to use the 
same data base for today's proposed rules as we used for the September 
1999 rule to save the time and resources required to collect new data, 
industry stakeholders wanted to submit new emissions data for us to 
consider in developing the replacement standards. Rather than allowing 
industry stakeholders to submit potentially selected emissions data, 
however, we agreed to undertake a substantial data collection effort in 
2002. It is unfortunate that industry stakeholders now suggest that 
some portion of the new data is not appropriate for establishing MACT.
---------------------------------------------------------------------------

    \35\ However, we did not consider emissions data from Ash Grove 
Cement Company (Chanute, Kansas), an owner and operator of a new 
preheater/precalciner kiln, because the test report is a MACT 
comprehensive performance test demonstrating compliance with the new 
source standards of the September 1999 final rule. We judged these 
data are inappropriate for consideration for the floor analyses for 
existing sources.
---------------------------------------------------------------------------

    Notwithstanding our view that all of the 2002 data base should be 
considered in establishing MACT standards, we

[[Page 21218]]

specifically request comment on: (1) Whether emissions data should be 
deleted from the data base that were obtained from sources that owners 
and operators assert were upgraded to meet the 1999 rule; and (2) 
whether, because it may be problematic to identify such data, we should 
identify MACT using the original 1999 data base.
    Stakeholders have also raised concerns that the Agency may be 
considering inappropriately emissions data in its MACT analyses based 
on the language of section 112(d)(3)(A) of the Clean Air Act. Section 
112(d)(3)(A) says emissions standards for existing sources shall not be 
less stringent, and may be more stringent than--

the average emission limitation achieved by the best performing 12 
percent of the existing sources (for which the Administrator has 
emissions information), excluding those sources that have, within 18 
months before the emission standard is proposed or within 30 months 
before such standard is promulgated, whichever is later, first 
achieved a level of emission rate or emission reduction which 
complies, or would comply if the source is not subject to such 
standard, with the lowest achievable emission rate (as defined by 
section 171) applicable to the source category and prevailing at the 
time, in the category or subcategory for categories and 
subcategories with 30 or more sources,

    Section 171 pertains to nonattainment areas for a particular 
pollutant. The lowest achievable emission rate (LAER) for a pollutant 
in a nonattainment area is the most stringent emission limitation which 
is contained in the implementation plan of any State, or the most 
stringent emission limitation which is achieved in practice. Given that 
stakeholders neither identified any lowest achievable emission rates 
for any pollutants applicable to nonattainment areas nor identified any 
sources that are subject to such lowest achievable emission rates, we 
conclude that there are no sources to exclude.

B. Data Base for Phase II Sources

    Phase II sources are comprised of boilers and hydrochloric acid 
production furnaces that burn hazardous waste. The data base for Phase 
II sources was initially compiled by EPA in 1999. In developing this 
data base, we collected the most recent test report available for each 
source that included test results under compliance test operating 
conditions. The most recent test report, however, may have also 
included data used for other purposes (e.g., risk burn to obtain data 
for a site-specific risk assessment), which are also included in the 
data base. In nearly all instances, the dates of the test reports 
collected were either 1998 or 1999.
    After the initial compilation, we published the Phase II data base 
for public comment in June 2000 (65 FR 39581, June 27, 2000). Since the 
June 2000 notice, we have not collected additional emissions data for 
Phase II sources; however, we revised the data base to address public 
comments received in response to the June 2000 notice. We noticed the 
Phase II data base (together with the one for Phase I sources) for 
public comment in July 2002 (67 FR 44452, July 2, 2003) and revised the 
data base based on comments received. The current data base for Phase 
II sources contains test reports for over 115 boilers and 17 
hydrochloric acid production furnaces. See USEPA ``Draft Technical 
Support Document for HWC MACT Replacement Standards, Volume II: HWC 
Emissions Data Base,'' March 2004.

C. Classification of the Emission Data

    The hazardous waste combustor data base \36\ comprises emissions 
data from tests conducted for various purposes, including compliance 
testing, risk burns, annual performance testing, and research testing. 
Therefore, some emissions data represent the highest emissions the 
source has emitted in each of its compliance demonstrations, some data 
represent normal or typical operating conditions and emissions, and 
some data represent operating conditions and emissions during 
compliance testing in a test campaign where there are other compliance 
tests with higher emissions.
---------------------------------------------------------------------------

    \36\ Though the Phase I and II data bases were developed and 
titled separately, for purposes of today's proposal we are combining 
both into one data base termed the ``hazardous waste combustor data 
base.''
---------------------------------------------------------------------------

    Hazardous waste combustors generally emit their highest emissions 
during RCRA compliance testing while demonstrating compliance with 
emission standards. For real-time compliance assurance, sources are 
required to establish limits on particular operating parameters that 
are representative of operating levels achieved during compliance 
testing. Thus, the emission levels achieved during these compliance 
tests are typically the highest emission levels a source emits under 
reasonably anticipable circumstances. To ensure that these operating 
limits do not impede normal day-to-day operations, sources generally 
take measures to operate during compliance testing under conditions 
that are at the extreme high end of the range of normal operations. For 
example, sources often feed ash, metals, and chlorine during compliance 
testing at substantially higher than normal levels (e.g., by spiking 
the waste feed) to maximize the feed concentration, and they often 
detune the air pollution control equipment to establish operating 
limits on the control equipment that provide operating flexibility. By 
designing the compliance test to generate emissions at the extreme high 
end of the normal range of emissions, sources can establish operating 
limits that account for variability in operations (e.g., composition 
and feedrate of feedstreams, as well as variability of pollution 
control equipment efficiency) and that do not impede normal operations.
    The data base also includes normal emissions data that are within 
the range of typical operations. Sources will sometimes measure 
emissions of a pollutant during a compliance test even though the test 
is not designed to establish operating limits for that pollutant (i.e., 
it is not a compliance test for the pollutant). An example is a trial 
burn where a lightweight aggregate kiln measures emissions of all RCRA 
metals, but uses the Tier I metals feedrate limit to comply with the 
mercury emission standard.\37\ Other examples of emissions data that 
are within the range of normal emissions are annual performance tests 
that some sources are required to conduct under State regulations, or 
RCRA risk burns. Both of these types of tests are generally performed 
under normal operating conditions, and would not necessarily reflect 
day-to-day emission variability. However, such data may be appropriate 
to use to evaluate long-term average performance.
---------------------------------------------------------------------------

    \37\ A Tier 1 feedrate limit is a conservative compliance option 
offered pursuant to RCRA requirements which assumes all of the 
metal/chlorine that is fed to the combustion unit is emitted 
(uncontrolled). Sources electing to comply with Tier 1 limits are 
not required to conduct emissions testing and are not required to 
establish operating parameter limits based on a compliance test. See 
Sec.  266.106.
---------------------------------------------------------------------------

    Other emissions tests may generate emissions in-between normal and 
the highest compliance test emissions. An example is a compliance test 
designed to demonstrate compliance with the particulate matter standard 
where: (1) The air pollution control equipment is detuned; and (2) the 
source measured lead and cadmium emissions even though it elected to 
comply with RCRA Tier 1 feedrate limits for those metals and, thus, 
does not spike those metals. We would conclude that lead and cadmium 
emissions--together they comprise the semivolatile metals--are between 
normal and the highest compliance test emissions. Emissions are not 
likely to be as high as

[[Page 21219]]

compliance test emissions because the source did not use the test to 
demonstrate compliance with emission standards for the metals (and so 
did not spike the metals). However, emissions of the metals are likely 
to be higher than normal because the air pollution control equipment 
was detuned.
    To distinguish between normal and compliance test data, we 
classified emissions data for each pollutant for each test condition as 
compliance test (CT); normal (N); in between (IB); or not applicable 
(NA).\38\ These classifications apply on a HAP-by-HAP basis. For 
example, some HAP measured during a test condition may be classified as 
representing compliance test emissions for those HAP, while other HAP 
measured during the test condition may be classified as representing 
normal emissions. See USEPA ``Draft Technical Support Document for HWC 
MACT Replacement Standards, Volume II: HWC Emissions Data Base,'' March 
2004, Chapter 2, for additional details.
---------------------------------------------------------------------------

    \38\ NA means the normal versus compliance test classification 
is not applicable. Research testing data is an example of the type 
of data that would get a NA rating.
---------------------------------------------------------------------------

D. Invitation To Comment on Data Base

    As previously discussed, we updated the data base based on comments 
received since it was last made publicly available. We believe the data 
base used to determine today's proposed standards is complete and 
accurate. However, given the complexity of the data base, we believe it 
is appropriate to once again solicit comments on the accuracy of the 
data. If you find errors, please submit the pages from the test report 
that document the missing or incorrect entries and the cover page of 
the test report as a reference. In addition, we identified several 
sources that are no longer burning hazardous waste and removed their 
emissions data and related information from the data base. We encourage 
owners and operators of hazardous waste combustors to review our list 
of operating combustors to ensure its accuracy. See USEPA ``Draft 
Technical Support Document for HWC MACT Replacement Standards, Volume 
III: Selection of MACT Standards and Technologies,'' March 2004.

IV. How Did EPA Select the Format for the Proposed Rule?

    The proposed rule includes emission limits for dioxin/furans, 
mercury, particulate matter, semivolatile metals, low volatile metals, 
hydrogen chloride/chlorine gas, and carbon monoxide or hydrocarbons. We 
also propose percent reduction standards for: (1) Destruction and 
removal efficiency \39\ for organic HAP; and (2) total chlorine control 
for hydrochloric acid production furnaces. Finally, sources would be 
required to establish operating parameter limits under prescribed 
procedures to ensure continuous compliance with the emission standards.
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    \39\ Please note that we propose today a destruction and removal 
efficiency standard only for boilers and process heaters and 
hydrochloric acid production furnaces. We are not reproposing the 
destruction and removal efficiency standard in subpart EEE currently 
in effect for incinerators, cement kilns, and lightweight aggregate 
kilns.
---------------------------------------------------------------------------

    We discuss below the rationale for: (1) Selecting an emission limit 
format rather than a percent reduction format in most cases; (2) 
selecting a hazardous waste thermal emissions format for the emission 
limit in some cases, and an emissions concentration format in others; 
(3) selecting surrogates to control multiple HAP; and (4) using 
operating parameter limits to ensure compliance with emission 
standards.

A. What Is the Rationale for Generally Selecting an Emission Limit 
Format Rather Than a Percent Reduction Format?

    Using emission limits as the format for most of the proposed 
standards provides flexibility for the regulated community by allowing 
a regulated source to choose any control technology or technique to 
meet the emission limits, rather than requiring each unit to use a 
prescribed method that may not be appropriate in each case. (See CAA 
section 112(h), relating to authority to adopt work place standards). 
Although a percent reduction format would allow flexibility in choosing 
the control technology to achieve the reduction, a percent reduction 
technology does not allow the option of achieving the standard by feed 
control--minimizing the feed of metals or chlorine. Consequently, we 
propose percent reduction standards only in special circumstances.
    We are proposing a percent reduction standard for boilers and 
hydrochloric acid production furnaces, i.e., a destruction and removal 
efficiency standard for organic HAP, because all sources currently 
comply with such a standard under RCRA and RCRA implementing rules. 
Further, we do not have emissions data on trace levels of organic HAP 
that would be needed to establish emission limits for particular 
compounds.
    We also propose a total chlorine percent reduction standard as a 
compliance option for hydrochloric acid production furnaces in lieu of 
the proposed stack gas concentration limit because a stack gas 
concentration limit may ultimately result in limiting the feed of 
chlorine to furnaces with MACT emission control equipment. Given that 
these furnaces produce hydrochloric acid from chlorinated feedstocks, 
limiting the feed of chlorine is inappropriate. See Part Two, Section 
VI.A and XII for more discussion on the total chlorine standard for 
hydrochloric acid production furnaces.

B. What Is the Rationale for Selecting a Hazardous Waste Thermal 
Emissions Format for Some Standards, and an Emissions Concentration 
Format for Others?

    We are proposing numerical emission limits in two formats: 
hazardous waste thermal emissions, and stack gas emissions 
concentrations. Hazardous waste thermal emissions are expressed as mass 
of pollutant contributed by hazardous waste per million Btu of heat 
contributed by hazardous waste. Emission concentration based standards 
are expressed as mass of pollutant (from all feedstocks) per unit of 
stack gas (e.g., [mu]g/dscm).
1. What Is the Rationale for the Hazardous Waste Thermal Emissions 
Format?
    In the 1999 rule, we assessed hazardous waste feed control levels 
for metals and chlorine by evaluating each source's maximum theoretical 
emission concentration (MTEC) using the ``aggregate MTEC'' approach. 
See 64 FR at 52854. MTEC is defined as the metals or chlorine feedrate 
divided by the gas flow rate, and is expressed in [mu]g/dscm. We used 
MTECs to assess feed control levels because it normalizes metal and 
chlorine feedrates across sources of different sizes. Industry 
stakeholders have claimed that use of MTECs to assess feed control 
levels for energy recovery units (e.g., cement kilns) when establishing 
floor standards inappropriately penalizes sources that burn hazardous 
waste fuels at high firing rates (i.e., percent of heat input from 
hazardous waste). This is because hazardous waste fuels generally have 
higher levels of metals and chlorine than the fossil fuels they 
displace, thus metal and chlorine feedrates and emissions may increase 
as the hazardous waste firing rate increases.
    Although we are not using the aggregate MTEC approach to evaluate 
feed control in today's proposal, the SRE/Feed approach explained in 
Part Two, Section VI.A, does assess each source's metal and chlorine 
hazardous waste feed control levels. In order to avoid the hazardous 
waste firing rate bias discussed above for energy recovery

[[Page 21220]]

units, we believe it is appropriate to instead assess feed control for 
energy recovery units by ranking each source's thermal feed 
concentration, which is equivalent to the mass of metal or chlorine in 
the hazardous waste per million BTUs hazardous waste fired to the 
combustion unit. This approach not only normalizes metal and chlorine 
feedrates across sources of different sizes, but also normalizes these 
feedrates across energy recovery units with different hazardous waste 
firing rates. For example, a kiln that feeds hazardous waste with a 
given metal concentration to fulfill 100% of its energy demand would be 
an equally ranked feed control source when compared to an identical 
kiln that fulfills 50% of its energy demand from coal and 50% from 
hazardous waste with an identical metal concentration.
    Similarly, it is our preference to express today's proposed 
emission standards for metals and chlorine in units of hazardous waste 
thermal emissions as opposed to expressing the standards in units of 
stack gas concentrations. As previously discussed, hazardous waste 
thermal emission standards are expressed as mass of HAP emissions 
attributable to the hazardous waste per million Btu hazardous waste 
fired to combustor. As with thermal feed concentration, thermal 
emissions normalizes emissions across energy recovery units with 
different hazardous waste firing rates. The hazardous waste thermal 
emissions format addresses two concerns. First, it avoids the above 
discussed bias against sources that burn hazardous waste fuels at high 
firing rates. We prefer not to discourage energy recovery from 
hazardous waste as opposed to potentially establishing standards that 
effectively restrict the hazardous waste firing rate in an energy 
recovery combustor. (See, for example, the requirement in CAA section 
112(d)(2) to take energy considerations into account when promulgating 
MACT standards, as well as the objective in RCRA section 1003(b)(6) to 
encourage properly conducted recycling and reuse of hazardous waste).
    Second, because the hazardous waste thermal emissions approach 
controls only emissions attributable to the hazardous waste feed (see 
discussion in following section), the rule can be simplified by not 
including waivers for sources that cannot meet the standard because of 
metals or chlorine contributed by nonhazardous waste feedstreams. To 
ensure that hazardous waste combustors will be able to achieve the 
standards if they use MACT control for metals and chlorine attributable 
to the hazardous waste feed, but irrespective of metals and chlorine in 
nonhazardous waste feedstreams, current MACT standards for cement and 
lightweight aggregate kilns that burn hazardous waste provide 
alternative standards that sources can request under a petitioning 
procedure. See Sec.  63.1206(b)(9-10). These alternative standards 
would be unnecessary under the hazardous waste thermal emissions 
approach because, by definition, the approach controls only hazardous 
waste-derived metals and chlorine.
2. Which Standards Would Use the Hazardous Waste Thermal Emissions 
Format?
    We propose a hazardous waste thermal emissions format for mercury, 
semivolatile metals, low volatile metals, and total chlorine (i.e., the 
HAPs found in hazardous waste fuels) for source categories that burn 
hazardous waste fuels where we have data to calculate a hazardous waste 
thermal emissions limit. Cement kilns, lightweight aggregate kilns and 
liquid-fuel fired boilers burn hazardous waste fuels and are thus 
candidates for the hazardous waste thermal emission standards. 
Incinerators and solid fuel-fired boilers are not candidates for 
thermal emission standards because some sources within these source 
categories do not combust hazardous waste for energy recovery, i.e., 
they burn low heating value hazardous waste for the purpose of treating 
the waste.\40\ Consequently, these sources could not duplicate a 
hazardous waste thermal emissions standard based on emissions from 
sources that burn hazardous waste fuels, even though their stack gas 
emission concentrations could be as low or lower than emissions from a 
best performing source under the hazardous waste thermal emissions 
approach.
---------------------------------------------------------------------------

    \40\ Three of the 13 solid fuel-fired boilers burn low heating 
value hazardous waste for treatment.
---------------------------------------------------------------------------

    We propose a hazardous waste thermal emissions format for all HAP 
for which we can apportion emissions between the hazardous waste fuel 
feed and other feedstreams. Under this approach, we apportion total 
stack emissions between hazardous waste fuel and other feedstreams 
using the ratio of the feedrate contribution from hazardous waste to 
the total feedrate of the pollutant. Thus, the particulate matter, 
metals, and total chlorine standards are candidates because we often 
have data on hazardous waste and total feedrates of these pollutants.
    We believe, however, that a hazardous waste thermal emissions 
format is not appropriate for particulate matter for cement and 
lightweight aggregate kilns because particulate matter emissions from 
cement and lightweight aggregate kilns are primarily entrained raw 
material, not ash contributed by the hazardous waste fuel. There is 
therefore no correlation between particulate matter emissions and 
hazardous waste thermal input rate.
    In addition, please note that we could have expressed the proposed 
particulate matter standard for liquid boilers in units of hazardous 
waste thermal emissions since (unlike the case of kilns just discussed) 
particulate matter emissions are attributable to the hazardous waste 
fuel. However, for consistency, we elected to use the same format for 
all the particulate matter standards. We invite comment as to whether 
the particulate matter standard for liquid boilers should be expressed 
in units of hazardous waste thermal emissions.
    We do not have adequate data to establish hazardous waste thermal 
emissions-based standards for several cases. An example is when we have 
only normal feedrate and emissions data (e.g., the mercury standard for 
cement kilns). We prefer to establish emission standards under the 
hazardous waste thermal emissions format using compliance test data 
because the metals and chlorine feedrate information from compliance 
tests that we use to apportion emissions to calculate emissions 
attributable to hazardous waste are more reliable than feedrate data 
measured during testing under normal, typical operations.\41\ Thus, as 
a general rule, we prefer to express emission standards for energy 
recovery units using the hazardous waste thermal emissions format only 
when we have sufficient compliance test feed data.\42\ These situations 
are discussed below in more detail in Part Two, Sections VIII, IX, and 
XI where we discuss the rationale for the proposed emission standards 
for energy recovery units.
---------------------------------------------------------------------------

    \41\ Feedrate data from testing during normal, typical 
operations may not be as accurate as data from compliance testing 
because of the sampling and analytical error associated with low 
feedrates. In contrast, sources generally spike metals and chlorine 
during compliance testing, so that measurement error is somewhat 
masked by the higher feedrate values.
    \42\ Two exceptions are the mercury and semivolatile metal 
standard for liquid fuel-fired boilers. We propose to express this 
standard in the hazardous waste thermal emissions format even though 
it is based on normal test data because we do not use feedrate data 
to apportion emissions in this case. Rather, we assume semivolatile 
metal emissions from liquid fuel-fired boilers are attributable 
solely to the hazardous waste given that these sources co-fire 
hazardous waste with natural gas or, in a few cases, fuel oil.

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[[Page 21221]]

3. How Are Emissions From Other Feedstreams Regulated Under the 
Hazardous Waste Thermal Emissions Format?
    Under the thermal emissions format, only emissions of HAP 
contributed by the hazardous waste are directly regulated by today's 
proposed standards. Non-mercury metal HAP emissions from raw materials 
and fossil fuels would be subject to MACT standards, even though it may 
not be feasible to directly control their feedrate. We are proposing 
standards for particulate matter as surrogates to control these HAP 
metals contributed by raw materials and fossil fuel.

C. What Is the Rationale for Selecting Surrogates To Control Multiple 
HAP?

    HWCs can emit a wide variety of HAP, depending on the types and 
concentrations of pollutants in the hazardous waste feed. Because of 
the large number of HAP potentially present in emissions, we propose to 
use several surrogates to control multiple HAP. This will reduce the 
burden of implementation and compliance on both regulators and the 
regulated community.
1. Surrogates for Metal HAP
    We are proposing to control metal HAP emissions attributable to the 
hazardous waste by subjecting sources to metal and particulate matter 
emission limitations.\43\ We grouped metal HAP according to their 
volatility because volatility is a primary consideration when selecting 
an emission control technology.\44\ We then considered the following to 
identify metals that would be ``enumerated'' and directly controlled 
with an emission limit: (1) The amount of available data for the metal 
HAP; (2) the potential for hazardous waste to contain substantial 
levels of a metal; and (3) the toxicity of the metal. Other, 
``nonenumerated'' metal HAP would be controlled using particulate 
matter as a surrogate.
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    \43\ As discussed later, we are also propsoing particulate 
matter standards to generally serve as surrogates to control 
relevant metal HAP in non-hazardous waste feed streams when 
appropriate.
    \44\ See 64 FR at 52845-47 (September 30, 1999).
---------------------------------------------------------------------------

    Mercury is highly volatile, especially toxic, and may not be 
controllable by the same air pollution control mechanisms as the other 
HAP metals, so we are proposing a standard for mercury individually. 
Two semivolatile metals can be prevalent in hazardous waste and are 
particularly hazardous: lead and cadmium. We group these two metals 
together and propose an emission standard for these metals, combined. 
The combined emissions of lead and cadmium cannot exceed the 
semivolatile metal emission limit. Three low volatile metals can be 
prevalent in hazardous waste and are particularly hazardous: arsenic, 
beryllium, and chromium. We group these three metals together and 
propose an emission standard for these metals, combined. The combined 
emissions of arsenic, beryllium, and chromium cannot exceed the low 
volatile metal emission limit.
    The particulate matter standard generally serves as a surrogate to 
control non-enumerated metals in the hazardous waste as well as a 
surrogate to control relevant metal HAP in non-hazardous waste feed 
streams. We generally chose not to propose numerical metal HAP emission 
standards that would have accounted for all metal HAP for two reasons 
(note that such an approach would be in lieu of a proposed particulate 
matter standard because particulate matter is not a listed HAP). We 
generally do not have as much compliance test emissions information in 
our database for the nonenumerated metal HAP compared to the enumerated 
metal HAP. Thus it would be more difficult to assess the control levels 
for these additional metals. We also believe that a particulate matter 
standard, in lieu of emission standards that directly regulate all the 
metals, simplifies compliance activities in that sources would not have 
to monitor feed control levels of these nonenumerated metals on a 
continuous basis.
    Note that particulate matter is not an appropriate surrogate where 
standards are based, in part (or in whole) on feedrate control. This is 
because, unlike the case where HAP metals are controlled by air 
pollution control devices, HAP metal reductions in hazardous waste 
feedrate are not necessarily correlated with particulate matter 
reductions, i.e., hazardous waste feedrate reductions could reduce HAP 
metal emissions without a correlated reduction in particulate matter 
emissions. (See National Lime, 233 F. 3d at 639 noting this 
possibility.) Moreover, particulate matter that is emitted generally 
contain greater percentages of HAP metals when the metal concentrations 
in the hazardous waste feed increase. Thus, low particulate matter 
emissions do not necessarily guarantee low metal HAP emissions, 
especially in instances where the hazardous waste feeds are highly 
concentrated with metal HAP.
    We do not believe that the proposed emission standards for 
semivolatile and low volatile metals serve as adequate surrogate 
control for the nonenumerated metal HAP. Compliance with the 
semivolatile and low volatile metal emission standards does not ensure 
that sources are using MACT back-end control devices because they could 
be achieving compliance by primarily implementing hazardous waste feed 
control for the enumerated metals. Thus, if a source uses superior feed 
control only for the enumerated metals, the nonenumerated metal 
emissions would not be controlled to MACT levels if it were not using a 
MACT particulate matter control device. The proposed semivolatile and 
low volatile metal standards are also inappropriate surrogates for 
controlling nonmercury metal HAP in the nonhazardous waste feedstreams 
for kilns and solid fuel-fired boilers for the same reason. These 
sources may comply with the proposed semivolatile and low volatile 
metal emission standards by implementing hazardous waste feed control. 
This would not assure that the nonmercury metal HAP emissions 
attributable to the nonhazardous waste feedstreams are controlled to 
MACT levels. A particulate matter standard provides this assurance.
    Note that we are proposing that incinerators and liquid boilers 
that emit particulate matter at levels higher than the proposed 
standard but do not emit significant levels of non-mercury metal HAP 
can elect to comply with an alternative standard. Under the proposed 
alternative standard, these sources would be required to: (1) Limit 
emissions of all semivolatile metals, including nonenumerated 
semivolatile metals, to the emission limit for semivolatile metals; and 
(2) limit emissions of all low volatile metals, including nonenumerated 
low volatile metals, to the emission limit for low volatile metals. See 
Part Two, Section XVIII for more discussion on this alternative.
2. Surrogates for Organic HAP
    For Phase II sources, we propose two standards as surrogates to 
control emissions of organic HAP: carbon monoxide or hydrocarbons, and 
destruction and removal efficiency.\45\ Both of these standards control 
organic HAP by ensuring combustors are operating under good combustion

[[Page 21222]]

practices that should result in destruction of the organic HAP. Note 
that boilers and hydrochloric acid production furnaces that burn 
hazardous waste are currently subject to RCRA requirements that 
regulate carbon monoxide or hydrocarbon emissions and destruction and 
removal efficiency standard under RCRA regulations. We propose to 
control dioxin/furans by a separate standard because dioxin/furan can 
also be formed post-combustion in ductwork, waste heat recovery 
boilers, or dry air pollution control devices (e.g., electrostatic 
precipitators and fabric filters).
---------------------------------------------------------------------------

    \45\ Please note that we are proposing the organic emission 
standards--carbon monoxide or hydrocarbons, and desturction and 
removal efficiency--for boilers and process heaters and hydrochloric 
acid production furnaces only. Requirements to comply with these 
standards are currently in effect under subpart EEE for 
incinerators, cement kilns, and lightweight aggregate kilns. We are 
not reporposing or reopening consideration of those standards in 
today's notice.
---------------------------------------------------------------------------

    Hydrocarbon emissions are a direct measure of many organic 
compounds, including organic HAP. Carbon monoxide emissions are a more 
conservative indicator of hydrocarbon and organic HAP emissions because 
the presence of carbon monoxide at elevated levels is indicative of 
incomplete oxidation of organic compounds. Sources generally choose to 
comply with the carbon monoxide standard because carbon monoxide 
continuous emissions monitors are less expensive and easier to maintain 
than hydrocarbon monitors.
    We also propose to use the destruction and removal efficiency 
standard to help ensure boilers and hydrochloric acid production 
furnaces operate under good combustion conditions. We propose to adopt 
the standard and implementation procedures that currently apply to 
these sources under RCRA regulations at Sec.  266.104. We propose, 
however, to require a one-time only compliance requirement for 
destruction and removal efficiency, unless a source changes its design 
or operation in a manner that could adversely affect its ability to 
meet the destruction and removal efficiency standard. Further, previous 
destruction and removal efficiency testing performed under RCRA could 
be used to document the one-time compliance.

D. What Is the Rationale for Requiring Compliance With Operating 
Parameter Limits To Ensure Compliance With Emission Standards?

    In addition to meeting emission limits, today's proposal would 
require sources to establish limits on key operating parameters for the 
combustor and emission control devices. Each source would establish 
site-specific limits for the parameters based on operations during the 
comprehensive performance test, using prescribed procedures for 
calculating the limits. The operating parameter limits would reasonably 
ensure that the combustor and emission control devices continue to 
operate in a manner that will achieve the same level of control as 
during the comprehensive performance test.
    We selected the operating parameters for which sources would 
establish limits because: (1) The parameters can substantially affect 
emissions of HAP; (2) they are feasible to monitor continuously; (3) 
they are currently used to monitor performance under the Interim 
Standards Rule for incinerators, cement kilns, and lightweight 
aggregate kilns that burn hazardous waste; and (4) this is the same 
general compliance approach that is currently applicable to all 
hazardous waste combustion sources pursuant to the RCRA emission 
standard requirements.

V. How Did EPA Determine the Proposed Emission Limitations for New and 
Existing Units?

A. How Did EPA Determine the Proposed Emission Limitations for New 
Units?

    All standards established pursuant to section 112 of the CAA must 
reflect MACT, the maximum degree of reduction in emissions of air 
pollutants that the Administrator, taking into consideration the cost 
of achieving such emission reduction, and any non-air quality health 
and environmental impacts and energy requirements, determines is 
achievable for each category. The CAA specifies that the degree of 
reduction in emissions that is deemed achievable for new hazardous 
waste combustors must be at least as stringent as the emissions control 
that is achieved in practice by the best-controlled similar unit (as 
noted earlier, this specified level of minimum stringency is referred 
to as the MACT floor, the term used when the statutory provision was 
first introduced in Congress). However, EPA may not consider costs or 
other impacts in determining the MACT floor. EPA may adopt a standard 
that is more stringent than the floor (i.e., a beyond-the-floor 
standard) if the Administrator considers the standard to be achievable 
after considering cost, environmental, and energy impacts.

B. How Did EPA Determine the Proposed Emission Limitations for Existing 
Units?

    For existing sources, MACT can be less stringent than standards for 
new sources, but cannot be less stringent than the average emission 
limitation achieved by the best-performing 12 percent of existing 
sources for categories and subcategories with 30 or more sources. EPA 
may not consider costs or other impacts in determining the MACT floor. 
The EPA may require a control option that is more stringent than the 
floor (beyond-the-floor) if the Administrator considers the cost, 
environmental, and energy impacts to be reasonable.
    It has been argued that EPA is limited in the level of performance 
it can evaluate in assessing which are the 12 percent existing best 
performing sources to standards codified in permits, or other 
regulatory limitations. The argument is based on use of the term 
``emission limitation'' in section 112 (d) (3), the argument being that 
``emission limitation'' is a term defined in section 302 (k) to mean 
``a requirement established by the State or the Administrator which 
limits the quantity, rate, or concentration of air pollutants * * *''. 
EPA does not accept this argument, and indeed doubts that such an 
interpretation of the statute is even permissible. In brief:
    (i) Statutory text indicates that MACT floors for existing sources 
is to based on actual performance. Section 112 (d) (3) (A) speaks to 
the actual performance of sources, and requires that the floor for 
existing sources reflect actual performance. The key statutory phrase 
is not just ``emission limitation'' but ``emission limitation 
achieved'', a phrase referring to actual performance, not just a limit 
simply set out in a permit or regulation. The floor is to be calculated 
using ``emissions information'', a reference again to actual 
performance. The provision likewise states that certain sources 
achieving a lowest achievable emission rate (LAER) level of performance 
without being subject to LAER (a regulatory limit) are not to be 
considered in assessing best performers, redundant language if only 
regulatory limits could be considered.
    In fact, it is clear from context when Congress used the term 
``emission limitation'' to refer to regulatory limits, and when it uses 
the term to refer to a level of performance actually achieved. Compare 
CAA section 111(b)(1)(B) (EPA is to consider ``emissions limitations 
and percent reductions achieved in practice'' when considering whether 
to revise new source performance standards) with section 110(a)(2)(A) 
(State Implementation Plans must contain ``enforceable emission 
limitations'').
    (ii) The argument leads to absurd and illegal results. The argument 
that existing source MACT floors can only be based on regulatory limits 
leads to results that are illegal, absurd, or both. Congress enacted 
section 112 to assure technology-based control of HAP which had 
heretofore gone unregulated due to the vagaries and glacial pace of

[[Page 21223]]

implementing the previous risk-based regime for HAP. 1 Legislative 
History at 790, 860; 2 Legislative History at 3174-78, 3340-42. The 
result, at the time of the 1990 amendments is that there were 
widespread regulatory limits for only one of the 190 listed HAPs (lead, 
for which there was a National Ambient Air Quality Standard) plus 
NESHAPs for a half dozen other HAPs. Thus, ``emission limitations'', in 
the sense used in the argument, did not exist for most HAPs. This would 
lead necessarily to the result of no existing source floors because no 
``emission limitations'' exist. This result is illegal. National Lime 
v. EPA, 233 F. 3d 625, 634 (D.C. Cir. 2000). Where regulatory limits 
are higher than actual performance levels, existing source floors 
likewise would be higher than performance levels, a result both absurd 
and illegal. Sierra Club v. EPA, 167 F. 3d 658, 662-63 (D.C. Cir. 
1999). In fact, at the time of the 1999 rule for this source category 
(hazardous waste combustion), RCRA regulatory limits were higher than 
the level of performance achieved even by the very worst performing 
source in the category (for some HAPs, by orders of magnitude). Yet 
under the argument, the floor for existing sources would have to be 
higher than even this worst performing single source.
    (iii) Legislative History shows that Congress intended the existing 
source floor to reflect actual best performance. The legislative 
history to the MACT floor provision for existing sources likewise makes 
clear that the standard was to reflect actual performance, not 
regulatory limits. 2 Legislative History pp. 2887, 2898; 3353; 1 
Legislative History p. 870. The legislative history to the parallel 
provision for municipal waste combusters in section 129(a)(2) (which 
floor requirement reads identically to section 112(d)(3)) is equally 
clear, stating that the floor for such sources is to reflect emission 
limitations which either have been achieved in practice or are 
reflected in permit limitations, whichever is more stringent. See 
Sierra Club v. EPA, 167 F. 3d at 662 (noting this legislative history.)
    (iv) The argument has already been rejected in litigation. The D.C. 
Circuit, in the three cases dealing with MACT floors, has held in all 
three cases that the floor standard must reflect actual performance. 
Sierra Club, 167 F. 3d at 162-63; National Lime, 233 F. 3d at 632; 
Cement Kiln Recycling Coalition, 255 F. 3d at 865-66.
    For these reasons, we reject the argument that existing source 
floors are compelled to reflect only regulatory limits. Such limits may 
be a permissible means of establishing existing source floors, but only 
if regulatory limits ``are a reasonable means of estimating the 
performance of the top 12 percent of [sources] in each [category or 
subcategory].'' Sierra Club, 167 F. 3d at 661.
    Somewhat ironically, there is a regulatory limit which is relevant 
in establishing floors for incinerators, cement kilns and lightweight 
aggregate kilns. The interim standards fix a level of performance for 
all of these sources. Thus, any floor standard can be no less stringent 
than this standard (see National Lime 233 F. 3d at 640 (reason for 
which a level of performance is being achieved is irrelevant in 
ascertaining MACT floors)). Based on actual performance, however, 
floors may be more stringent.

VI. How Did EPA Determine the MACT Floor for Existing and New Units?

    We followed five basic steps to calculate the proposed MACT floors. 
First, we determined which MACT methodology approach is most 
appropriate to apply to the given pollutant for each source category. 
Second, we selected which of the available emissions data best 
represent each source's performance. Third, we evaluated whether it is 
appropriate to issue separate emissions standards for various 
subcategories. Fourth, we identified the best performing sources based 
on the chosen methodology and data. Finally, we calculated floor levels 
for new and existing sources. The following sections include a 
description of each of these steps. Please note that we are also 
proposing to invoke CAA section 112(d)(4) to establish risk-based 
standards on a site-specific basis for total chlorine for hazardous 
waste combustors (except for hydrochloric acid production furnaces). 
Under the proposed approach, sources may elect to comply with either 
risk-based standards or section 112(d) MACT standards. See Part Two, 
Section XIII for more details.

A. What MACT Methodology Approaches Are Used To Identify the Best 
Performers for the Proposed Floors, and When Are They Applied?

    A MACT methodology approach is a set of procedures used to define 
and identify the best performing sources consistent with CAA section 
112(d)(3). We have developed and used the following three different 
MACT methodologies to identify the best performing sources for the full 
suite of proposed floor standards for new and existing sources: (1) 
System Removal Efficiency (SRE)/Feed approach; (2) Air Pollution 
Control Technology Approach; and (3) Emissions-Based approach. These 
three methodologies, together with their rationales and when they are 
used, are described in the following sections. Note that each 
methodology described below assesses best performing sources for each 
pollutant or pollutant group independently, often resulting in 
different best performers for each pollutant. For a more detailed 
description of these methodologies and when they are applied, see USEPA 
``Draft Technical Support Document for HWC MACT Replacement Standards, 
Volume III: Selection of MACT Standards,'' March 2004, Chapters 7 
through 15.
1. What Is SRE/Feed Approach, and When Are We Proposing To Apply It?
    The SRE/Feed MACT approach defines best performers as those sources 
with the best combined front-end hazardous waste feed control and back-
end air pollution control efficiency as defined by our ranking 
procedure. The approach is applicable to HAP whose emissions can be 
controlled by controlling the hazardous waste feed of the HAP: metals 
and chlorine.\46\
    These two parameters--feedrate of metals and chlorine in hazardous 
waste, and performance of the emission control device measured by 
system removal efficiency \47\ determine emissions of metals and 
chlorine contributed by the hazardous waste feed. Back-end air 
pollution control is evaluated by assessing each source's pollutant 
system removal efficiency, which is a measure of the percentage of HAP 
that is emitted compared to the amount fed to the unit. In identifying 
system removal efficiency as a measure of best performing, the Agency 
is rejecting the notion that ``best performing'' must mean a source 
with the lowest absolute rate of emission of a HAP. A source emitting 
300 pounds of a HAP, but removing that HAP at a rate of 99.9% from its 
emissions, can logically be considered a better performing source than 
one emitting 100 pounds of the same HAP but

[[Page 21224]]

removing it at an efficiency of only 50 percent.
---------------------------------------------------------------------------

    \46\ The particulate matter standard is used as a surrogate to 
control nonmercury metal HAP in the nonhazardous waste feedstreams 
and to control the nonenumerated metals in the hazardous waste. As 
explained Part Two, Section VI.A.2.b., control of ash feed may not 
be an effective technique to control metal HAP. Thus, we do not use 
the SRE/Feed approach to identify floor levels for particulate 
matter since ash feed control may not be a reliable indicator of 
performance.
    \47\ Although system removal efficiency measures primarily the 
performance of the back-end emission control device, it also 
measures any other internal control mechanisms, such as partitioning 
of metals to the product in a cement or lightweight aggregate kiln.
---------------------------------------------------------------------------

    Use of feedrate and system removal efficiency as measures of 
performance is appropriate because these parameters incorporate the 
effects of the myriad factors that can indirectly affect emissions, 
such as level of maintenance of the combustor or emission control 
equipment, and operator training, as well as design and operating 
parameters that directly affect performance of the emission control 
device (e.g., air to cloth ratio and bag type for a fabric filter; use 
of a power controller on an electrostatic precipitator). For example, 
an incinerator with a well-designed and operated fabric filter would 
have a higher performance rating measured by system removal efficiency 
than an identical incinerator equipped with the same fabric filter 
which is, in addition, poorly maintained because of inadequate operator 
training. Also, although feedrate of metals and chlorine in 
nonhazardous waste feedstreams such as raw materials and fossil fuels 
fed to a cement kiln can affect HAP emissions substantially, those 
emissions can be feasibly controlled only by back-end control (measured 
here by system removal efficiency).\48\ This is because neither fuel 
switching nor raw material switching is practicable for production 
facilities such as cement and lightweight aggregate kiln facilities. 
Thus, feedrate of metals and chlorine contributed by the hazardous 
waste--the only controllable feed parameter for these sources--is an 
appropriate metric.
---------------------------------------------------------------------------

    \48\ See discussion in the proposed lime production MACT 
explaining why neither raw material or fossil fuel substitution are 
available means of controlling the feedrate of HAP. See 67 FR at 
78059-61 (Dec. 20, 2002). The rationale for lime kilns also applies 
to cement and lightweight aggregate kilns. Briefly, in the context 
of floor control: (1) A kiln's principle raw materials (limestone 
for cement kilns and clay for lightweight aggregate kilns) are not 
available to other kilns; and (2) we are not aware of raw materials, 
or sources of coal or oil, that have characteristic and consistent 
(low) concentrations of HAP. In the context of beyond-the-floor 
control, additional issues include: (1) The cost of transporting raw 
materials with lower levels of HAP (if it were feasible to identify 
them) would be prohibitive; and (2) although switching from coal or 
oil to natural gas would reduce the feedrate of HAP, the limitations 
of the natural gas distribution infrastructure are such that natural 
gas is not readily available to many sources.
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    For incinerators and solid fuel-fired boilers, feed control is 
evaluated by assessing each source's hazardous waste pollutant maximum 
theoretical emission concentration.\49\ Feed control for energy 
recovery units (cement kilns, lightweight aggregate kilns, and liquid 
fuel-fired boilers) are evaluated by assessing each source's hazardous 
waste pollutant thermal feed concentration when possible (i.e., when 
EPA has sufficient data to make the calculation).
---------------------------------------------------------------------------

    \49\ In the 1999 rule, we developed the term maximum theoretical 
emissions concentration to compare metals and chlorine feed control 
levels across sources of different sizes. See 64 FR at 52854. 
Maximum theoretical emissions concentration is defined as the metals 
or chlorine feedrate divided by the gas flowrate, and is expressed 
in terms of [mu]g/dscm. See Part Two, section IV.B.1 for more 
discussion on how we normalize feedrates and emissions across 
sources.
---------------------------------------------------------------------------

    We rank each source's pollutant hazardous waste feed control level 
against all the other source's feed control level, assigning a relative 
rank of 1 to the source with the lowest, i.e., best, feed control level 
and assigning the highest ranking score to the source with the highest, 
i.e., worst, feed control level. We do the same with each source's 
system removal efficiency. We rank each source's pollutant system 
removal efficiency against all the other sources' system removal 
efficiencies, assigning a relative rank of 1 to the source with the 
highest, i.e., best, system removal efficiency and assigning the 
highest ranking score to the source with the lowest, i.e., worst, 
system removal efficiency. We then add each source's feed control 
ranking score and system removal efficiency ranking score to yield an 
SRE/Feed aggregated score. Each source's aggregated score is arrayed 
and ranked from lowest to highest, i.e., best to worst, and, for 
existing sources, the best performers are the sources at the 12th 
percentile aggregate score and below. Floor levels are then calculated 
by using the emissions from these best performing sources. The SRE/
Feed-based standards are expressed in units of hazardous waste thermal 
emissions when possible for energy recovery units.
    Please note that the SRE/Feed approach can occasionally identify a 
floor level for new sources that is higher than the floor level for 
existing sources, as discussed below in Sections VII to XII. This is 
because the source with the best SRE/Feed aggregate score, and thus, 
the single best performing source under this approach, does not always 
achieve the lowest emissions among the best performing sources after 
accounting for emissions variability. In two cases only, the emissions 
for the best performing SRE/Feed source, after accounting for emissions 
variability, are higher than the average of the best performing five 
(or 12%) of sources--the floor for existing sources--after considering 
emissions variability.\50\ For example, the single best performing SRE/
Feed source may have both higher emissions and run variability than 
other best performing sources. This source's emissions are averaged 
with the other best performers to identify the floor level, and its run 
variability is dampened when we calculate the floor for existing 
sources by pooling run variability across the best performing sources. 
When the single best performer's emissions are evaluated individually, 
however, a relatively high run variability is not dampened. In those 
few situations where the best performing SRE/Feed source has higher 
emissions, after accounting for emissions variability (i.e., the 
potential floor for new sources), than the floor for existing sources, 
we default to the floor for existing sources to identify the floor for 
new sources. We request comment on whether it would be more appropriate 
to identify the floor for new sources under the SRE/Feed approach by 
selecting the source with the lowest emissions among the best 
performing existing sources, after considering run variability, rather 
than the lowest SRE/Feed aggregate score.
---------------------------------------------------------------------------

    \50\ This occurred for the low volatile metal standard for 
cement kilns and the mercury standard for solid-fuel fired boilers.
---------------------------------------------------------------------------

    The SRE/Feed methodology is generally applied only to HAP where we 
can accurately assess each source's relative hazardous waste feed 
control and back-end air pollution control: mercury, semivolatile 
metals, low volatile metals, and total chlorine. Dioxin/furans are not 
considered to be feed control HAP because they generally are not fed 
into the combustor; rather, they are formed in the combustor and post 
combustion. Also, whereas particulate matter (for all source 
categories) and total chlorine (for hydrochloric acid production 
furnaces) could be considered to be feed-controlled and back-end 
controlled pollutants, we do not believe it is appropriate to assess 
feed control as a control mechanism for these situations for reasons 
discussed below in Section 2 (largely dealing with the inability to 
control HAP in raw material feed or in fossil fuel). As a result, we 
did not apply the SRE/Feed approach to these pollutants.
    Finally, the SRE/Feed approach is also not applied when we do not 
have sufficient compliance test data to accurately assess each source's 
relative back-end control efficiency. This occurs in a limited number 
of circumstances when the majority of the emissions data reflect normal 
operations. The mercury and semivolatile metal standard for liquid 
boilers are examples of when we do not believe we possess sufficient 
data to accurately assess each source's back end control efficiency 
because we are concerned that the normal feed data are too sensitive to 
sampling and measurement error to provide a reliable

[[Page 21225]]

system removal efficiency that would be used reliably in the ranking 
procedure. Our preference is to use system removal efficiencies that 
are based on compliance testing because sources typically spike the 
pollutant feeds during these compliance tests to known elevated levels, 
resulting in calculated system removal efficiencies that are more 
reliable.
2. What Are the Air Pollution Control Technology Approaches, and When 
Are They Applied?
    The air pollution control technology approach is applied in two 
situations where we consider it inappropriate to directly assess 
hazardous waste feed control--the particulate matter standard for all 
sources categories and the total chlorine standard for hydrochloric 
acid production furnaces. We apply slightly different methodologies to 
each of these situations, as discussed below.
    a. What Methodology Was Used To Identify the Best Performing 
Sources for the Particulate Matter Floors? The best performing sources 
for the proposed particulate matter floor levels are determined using a 
methodology that is conceptually similar to that used in the Industrial 
Boiler MACT proposal. See 68 FR at 1660. We call this methodology the 
``air pollution control technology'' approach because it defines best 
performers as those that use the best type of back-end air pollution 
control technology.
    This methodology first assesses all the back-end control 
technologies used by all the sources within the source category, and 
ranks the general effectiveness of these control technologies from best 
to worst using engineering information and principles. For example, for 
particulate matter control, high efficiency particulate air filters may 
be ranked as the best air pollution control device, followed by 
baghouses, electrostatic precipitators, and high energy wet scrubbers. 
In this example, all sources equipped with a high efficiency 
particulate air (i.e., HEPA) filter would get the best ranking (e.g., 
``1''), and all sources equipped with high energy wet scrubbers would 
get the worst ranking (e.g., 4).
    The sources are arrayed and ranked from best to worst based on 
their control technology rankings. For existing sources, MACT control 
is defined as the control technology or technologies used by the best 
12 percent of these sources. For example, using the previous 
particulate matter control rankings, if more than 12 percent of the 
sources within the source category were using high efficiency 
particulate air filters, then MACT control would be defined to be high 
efficiency particulate air filters. If 10 percent of all the sources 
were equipped with high efficiency particulate air filters, and 4 
percent were equipped with baghouses, then MACT control would be 
defined as both high efficiency particulate air filters and baghouses.
    After the MACT control technology or technologies are determined, 
the MACT floor levels are calculated using emissions data from those 
sources using MACT control. See Part Two, Section IV.D.3 for more 
discussion on the ranking procedure that is used to identify the best 
performing sources under this approach. Also see USEPA ``Draft 
Technical Support Document for HWC MACT Replacement Standards, Volume 
III: Selection of MACT Standards,'' March 2004, Chapter 9, for more 
information. This methodology consequently focuses on performance of 
the best pollution control device, but does not assess further control 
that might result from lower HAP feedrates.\51\
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    \51\ This methodology does not, however, expand the MACT pool to 
include sources with emission levels greater than those of the best 
12 per cent of performers using MACT control (the approach the Court 
in CKRC held was inadequately justified as representing the 12 
percent of best performing sources).
---------------------------------------------------------------------------

    We believe it is appropriate to identify the best performing 
sources using particulate matter emissions from those using MACT back-
end control without considering hazardous waste ash feedrate control. 
For cement kilns, lightweight aggregate kilns, and solid fuel-fired 
boilers, particulate emissions are largely contributed by non-hazardous 
waste feedstreams (i.e., entrained raw material for kilns, and 
entrained coal ash for solid fuel-fired boilers). Thus, hazardous waste 
feed control is an inappropriate factor to consider when assessing 
particulate matter control efficiency. Assessment of, and control of, 
total ash feedrate (i.e., hazardous waste plus raw materials and 
nonhazardous waste fuel ash feed) would also be inappropriate because, 
as discussed below, total ash feedrate may not be a reliable indicator 
of a source's emission control level for metal HAP, and could 
inappropriately result in a methodology that assesses (and controls) 
raw material and/or nonhazardous waste fuel input.
    Although particulate matter emissions for incinerators and liquid 
fuel-fired boilers are more directly related to these devices' 
hazardous waste ash feedrate, the hazardous waste ash feedrate for 
these sources may not be a reliable indicator of a source's feedrate 
(and emissions) of nonenumerated metal HAP given that the ash feed into 
the combustor may contain high or low concentrations of regulated metal 
HAP. A source that feeds low levels of ash thus may not be a best 
performing source for metal HAP emissions if its metal concentration 
levels in its ash are relatively high. Such a source could be 
identified as a best performing source because its particulate matter 
emissions and ash feed is low, even though its metal HAP emissions are 
relatively high. This result would also inappropriately assess and 
control elements of the hazardous waste ash feed that are not regulated 
HAP (e.g., silica input). For these reasons, using the air pollution 
control technology approach to establish particulate matter floors 
without explicitly considering ash feedrate is appropriate since it 
focuses on the control technology (i.e., back-end air pollution control 
technology) that is known to control metal HAP emissions.\52\
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    \52\ Please note that, although we do not explicitly consider 
ash feedrate when establishing the particulate matter floor, ash 
feedrate is an appropriate and necessary compliance assurance 
parameter for incinerators and liquid fuel-fired boilers where ash 
from hazardous waste feedstreams contribute substantially (or 
entirely) to particulate emissions.
---------------------------------------------------------------------------

    b. What Methodology Is Used To Identify the Best Performing Sources 
for the Total Chlorine Floor for Hydrochloric Acid Production Furnaces? 
We apply the air pollution control technology approach to total 
chlorine for hydrochloric acid production furnaces differently. For 
this floor calculation, we are proposing to use the same methodology 
that the Agency used for the hydrochloric acid production MACT final 
rule for sources that do not burn hazardous waste. See 68 FR at 19076. 
This methodology defines best performers as those sources with the best 
total chlorine system removal efficiency. Each source's total chlorine 
system removal efficiency is arrayed and ranked from highest to lowest, 
and the best existing performers are the sources at the 12th percentile 
ranking and below. We calculate the system removal efficiency floor 
level using the total chlorine system removal efficiencies achieved by 
these best performing sources. Consistent with the non hazardous waste 
hydrochloric acid production MACT final rule, we also propose to allow 
sources to comply with a total chlorine stack gas concentration limit 
that is calculated by multiplying the highest hazardous waste chlorine 
maximum theoretical emission concentration in the data base by 1 minus 
the MACT system removal efficiency. This ensures that a source

[[Page 21226]]

complying with the alternative concentration-based standard would not 
emit higher levels of total chlorine than a source equipped with wet 
scrubbers that achieve MACT system removal efficiency. We believe this 
alternative standard is appropriate because it gives sources the option 
of complying with the floor by implementing hazardous waste feed 
control.\53\
---------------------------------------------------------------------------

    \53\ A source could operate with a ``less than MACT'' system 
removal efficiency provided that it controls its hazardous waste 
chlorine feed levels such that its emissions are lower than the 
emission standard.
---------------------------------------------------------------------------

    We believe this methodology is appropriate even though it does not 
directly assess hazardous waste total chlorine feed control because 
these sources are in the business of feeding highly chlorinated 
hazardous wastes so that they can recover the chlorine for use in their 
production process. Requiring these sources to minimize hazardous waste 
chlorine feed would be directly regulating their raw material and would 
directly affect their ability to produce their product. Again, in this 
situation, we believe it is appropriate to use a methodology approach 
that solely focuses on back-end control, since back-end control assures 
removal of the target pollutant without inappropriately requiring a 
source to control feedstreams in a manner that affects its ability to 
produce its intended product.
3. What Is the Emissions-Based Approach, and When Is It Applied?
    The emissions-based approach defines best performers as those 
sources with the lowest emissions in our database. We array and rank 
each source's pollutant emission levels from lowest to highest. The 
best existing performers are the sources at the 12th percentile ranking 
and below. We calculate floor levels using the emission levels from 
these best performing sources. We express the emissions-based standards 
in units of hazardous waste thermal emissions when possible for energy 
recovery units, and use the approach whenever the SRE/Feed or air 
pollution control technology approaches are not used. Specifically, we 
use the emissions-based approach for the dioxin/furan floors for all 
source categories, and for the mercury and semivolatile metal floors 
for liquid fuel-fired boilers.
    The SRE/Feed and air pollution technology-based approaches cannot 
be used for the dioxin/furan floors because dioxin/furans are generated 
in the combustor or post-combustion within the air pollution control 
device. Since dioxin/furans are generally not fed to the units, the 
SRE/Feed methodology would not properly assess dioxin/furan emission 
control performance. In theory, the technology-based approach for 
particulate matter could be applied to the dioxin/furan floors. 
However, such a technology approach would, for the most part, identify 
the same best performers as the emissions-based approach because there 
is only one primary control technology being used by all the sources--
temperature control at the inlet to the dry air pollution control 
device.
    The SRE/Feed approach cannot be used for the mercury and 
semivolatile metal floors for the liquid fuel-fired boilers because we 
do not have sufficient compliance test data to accurately assess each 
source's back-end control efficiency. The technology-based approach is 
also not appropriate because sources within this source category 
control these HAP both by feed control and by back-end control. As a 
result, a methodology that considers only one of the two primary 
control techniques may not be appropriate.
4. Why Doesn't EPA Simply Apply the Emissions-Based Approach to All 
Source Categories and HAP?
    Under the most simplistic interpretation of CAA 112(d), we would 
apply the emissions-based approach to all source categories and HAP in 
calculating floors for existing sources. We considered proposing this 
option. As described later in Part Two, Section VI.G, it was one of 
three options for which we conducted a complete economics analysis. We 
discuss below, however, why we believe the air pollution control 
technology and SRE/Feed approaches more reasonably ascertains the 
performance of the average of the best 12 percent of existing sources.
    a. Why Do We Prefer the SRE/Feed Approach Over the Emissions-Based 
Approach? We believe the SRE/Feed approach is a reasonable and 
appropriate MACT methodology for the hazardous waste combustion source 
categories because it better estimates the performance of the average 
of the 12 percent best performing sources, and (as a necessary 
corollary) assures that the floor standards would be achievable by such 
sources. As previously discussed, we apply the SRE/Feed approach to HAP 
that are actively controlled (via floor controls) by both hazardous 
waste feed control and back-end air pollution control. There are only 
two ways to control emissions of these HAP from these sources--limit 
the feedrate of metal and chlorine and remove them prior to venting the 
exhaust gas out the stack. These two control mechanisms are used 
simultaneously by all sources in this category at varying levels.
    We do not believe the lowest emission levels in our data base in 
fact represent the full range of emissions achieved in practice by the 
best performing sources. Indeed, it would be unlikely if this were the 
case, since these data are necessarily ``snapshots'' of emissions from 
the source, obtained in one-time testing events.\54\ Notwithstanding 
that such testing seeks to encompass much of the variability in system 
performance, no single test can be expected to do so. Thus, inherent 
variability such as feedrate fluctuation over time due to production 
process changes, uncertainties associated with correlations between 
operating parameter levels and emissions, precision and accuracy 
differences in different testing crews and analytical laboratories, and 
changes in emission of materials (SO2 being an example) that 
may cause test method interferences. See generally 64 FR at 52857and 
52587-59.
---------------------------------------------------------------------------

    \54\ One-time testing events, however, are a necessity because 
Continuous Emission Monitors still do not exist for most of the HAPs 
emitted by these sources.
---------------------------------------------------------------------------

    An emissions-based approach for cement kilns, lightweight aggregate 
kilns, and solid fuel-fired boilers that assesses performance based on 
stack gas concentrations (as opposed to hazardous waste thermal 
emissions) may not appropriately estimate the performance of the 
average of the 12 percent best performing sources given that those best 
performers may have low emissions in part because their raw material 
and/or fossil fuels contained low levels of HAP during the emissions 
test. We do not believe feed control of HAP in raw material and fossil 
fuel should be assessed as a MACT floor control primarily because it 
could result in floor levels that are not replicable by the best 
performing sources, nor duplicable by other sources. See Part Two, 
Section VI.A.1.
    Moreover, although the emissions-based approach is not facially 
inconsistent with section 112 of the Act, there are serious questions 
as to whether its applicability here leads to limits that could be 
achieved even by the average of the best performing sources (under the 
emissions-based approach). The alternative emissions-based floor 
Options 1 and 2 discussed in Part Two, Section VI.G result in floor 
levels across all HAP that are achievable simultaneously by fewer than 
6% of the sources for the cement kiln, incinerator, and liquid fuel-
fired boiler source

[[Page 21227]]

categories.\55\ See USEPA ``Draft Technical Support Document for HWC 
MACT Replacement Standards, Volume III: Selection of MACT Standards,'' 
March 2004, Chapters 10 and 19, for a summary of the simultaneous 
achievability analysis. A reason the floors which would result from 
this methodology are so low is that there already have been at least 
one and, for many of the sources, two rounds of regulatory reduction of 
emissions from these sources (under the RCRA rules, and then under the 
Interim Standards MACT rules for incinerators and kilns). The 
emissions-based approach thus yields results more akin to new source 
standards, confirmation being that the levels are not even achievable 
as a whole by the average of the 12 percent best performing sources. 
The simultaneous achievability of today's proposed floors, for which we 
use the SRE/Feed approach for certain HAP preferentially over the 
emissions-based approach, is substantially better (but not dramatically 
more than 6%) for cement kilns and liquid fuel-fired boilers than the 
achievability under the emissions-based approach.
---------------------------------------------------------------------------

    \55\ Simultaneous achievability percentages for lightweight 
aggregate kilns, solid fuel-fired boilers, and hydrochloric acid 
production furnaces must be interpreted differently given that there 
are significantly fewer than 30 sources within these source 
categories. As a result, we believe that the emission standards 
should be simultaneously achievable by at least two or three sources 
for these source categories given that CAA 112(d) defines best 
performing sources as the average of the best five sources.
---------------------------------------------------------------------------

    There are other reasons why the emissions-based approach results in 
such low simultaneous achievability percentages. If the emissions-based 
approach is applied to feed-controlled HAP, the best performers are 
defined as those sources that are either: (1) The lowest feeders; (2) 
the best back-end controlled units; or (3) the best combination of 
front-end control or back-end control. The emissions-based approach 
selects the lowest emitters from the previous three categories and does 
not necessarily account for the full range of emissions that are 
achieved in practice by well designed and operated feed control units, 
well designed and operated back-end controlled units, or well designed 
and operated combination of both front-end and back-end controlled 
units. As explained below, the SRE/Feed methodology better accounts for 
the range of emissions from these well designed and operated 
sources.\56\
---------------------------------------------------------------------------

    \56\ Note, however, that many of the best performing sources for 
the SRE/Feed approach are the same as those for emissions-based 
approach, primarily because there is a good correlation between the 
SRE/Feed aggregated ranking score and emissions in that the emission 
levels generally increase as the as the aggregate ranking score 
increases.
---------------------------------------------------------------------------

    For example, assume we have 100 sources in a hypothetical source 
category, and source A is the 5th best feed controlled source and the 
30th best back-end controlled source. Source B, on the other hand, is 
the 30th best feed controlled source and the 5th best back-end 
controlled source. The SRE/Feed ranking procedure would score these two 
sources equally, even though their emissions may be different. Let's 
also assume that these two sources are among the best performers for 
the SRE/Feed approach. We would not expect their emission levels to be 
dramatically different under the SRE/Feed approach because source A is 
a superior front-end controlled source with a relatively poorer back-
end control device, and source B is a superior back-end controlled 
source with relatively poorer feed control. Even though sources A and B 
do not have the same emissions, they are both considered to be well 
designed and operated sources because they both use a superior 
combination of front-end and back-end control. The difference in 
emissions merely reflects the range of emissions from well designed and 
operated sources.
    If the emissions-based approach was applied in the source A and B 
example, the source with the higher emissions would have a worse 
emission ranking, and thus may not be identified as a best performer. 
Thus, even though we would consider this higher emitting source under 
the SRE/Feed approach to be a well-designed and operated source, it 
would not be capable of achieving the calculated floor level. We 
believe this outcome may be problematic, for example, because sources 
that are already operating with a well-designed and operated back-end 
control unit should not have to upgrade its back-end control technology 
simply because it is not achieving a floor level driven, in part, by 
other sources within the source category that are implementing lower 
feed control rates that are impractical for it to achieve.\57\ It may 
be questionable to require these well controlled back-end units to 
implement better feed control to achieve this emission-based floor 
level because: (1) they may not be capable of implementing feed control 
without sending/diverting the waste elsewhere--yet these units are 
providing a needed and required service in treating hazardous waste; 
and (2) it could be argued that hazardous waste containing high levels 
of metals and chlorine should in fact be treated in the well-designed 
and operated back-end controlled units (see RCRA sections 3004 (d) to 
(m), requiring advanced treatment of hazardous waste before the waste 
can be land disposed).
---------------------------------------------------------------------------

    \57\ Moreover, the superior low metal and chlorine feedrates 
that on-site incinerators and boilers are ``achieving'' may simply 
reflect the composition of the waste generated by the manufacturing 
operation.
---------------------------------------------------------------------------

    Similarly, sources that are already achieving superior feedrate 
control should not necessarily have to upgrade their feedrate control 
further simply because they are not achieving a floor level driven, in 
part, by sources with superior back-end control. Improving already 
superior feedrate control may be problematic simply because they may 
not be capable of implementing additional feed control (e.g., source 
reduction) at their facility, or having generators implement further 
feedrate control. EPA believes that hazardous waste feed control is an 
important element of what constitutes ``best performing'' sources from 
this source category, and does not wish to structure the rule to 
discourage the practice by developing standards which do not directly 
take this means of control into account. See CAA section 112(d)(2)(A) 
(feed control is an explicit means of achieving MACT); and see also the 
pollution prevention and waste minimization goals of both the CAA 
(sections 112(d) (2) and 101(c) and RCRA (section 1003(b)). The SRE/
Feed approach thus better preserves the opportunity for sources to 
achieve the floor levels if they are using either superior front-end 
control or back-end control (or superior combination of both). At the 
same time, it addresses both means by which sources in this category 
can control their HAP emissions: hazardous waste feed control and back-
end air pollution capture through control technology.
    The example in the previous paragraph of the source using superior 
feed control is clearly applicable to incinerators and boilers that 
combust hazardous waste. These are somewhat unique source categories in 
that they are comprised of many different industrial sectors that may 
not be capable of achieving/duplicating the same metal and chlorine 
feedrate control levels of other sources within their respective source 
category given that hazardous waste feed control levels are directly 
influenced by amount of HAP that are generated in their specific 
production process. Similarly, other sources that comprise commercial 
hazardous waste combustors (i.e., kilns and commercial incinerators) 
are subject to the feed control levels that are governed

[[Page 21228]]

primarily by third parties (i.e., the generators or fuel blenders). The 
emissions-based approach identifies the best performers as those 
sources with the lowest emissions and does not consider differences in 
emission characteristics across all the industrial sectors that combust 
hazardous waste. We contemplated whether we should assess if 
subcategorization is appropriate based on the various industrial 
sectors that combust hazardous waste. We believe, however, that such an 
assessment would be difficult given the vast number of industrial 
sectors that generate hazardous waste which is treated by combustion.
    The emissions-based approach could be identifying a suite of floor 
levels across HAP that would require sources to operate at feedrate 
control levels in the aggregate that are in theory achieved by few, if 
any, well-operated and designed feed controlled sources. For example, 
the best performing sources for the emissions-based approach for the 
incinerator semivolatile and low volatile metal floors are entirely 
different. This may occur because sources have different relative feed 
control levels for mercury, semivolatile metals, low volatile metals, 
and total chlorine (e.g., a source could have superior semivolatile 
metal feed control but only moderate low volatile metal feed control).
    Finally, the emissions-based approach may result in low 
simultaneous achievability percentages because a back-end control 
technology for one pollutant may not control the emissions of another 
pollutant as efficiently. For example, wet air pollution control 
systems may control total chlorine emissions very well, but are not as 
efficient at limiting particulate matter emissions when compared to a 
baghouse. Thus, best performers under the emissions-based floor 
approach for total chlorine could be driven by sources with wet air 
pollution control systems, and the particulate matter floor could be 
driven by sources equipped with baghouses, resulting in a combined set 
of floors that are conceivably achieved by few sources, a result 
confirmed, as noted above, in that less than 6% of existing sources 
would be achieving floor standards developed using the emission-based 
approach.\58,\ \59\
---------------------------------------------------------------------------

    \58\ Although the SRE/Feed approach does not directly address 
this issue within the methodology, the simultaneous achievability of 
the SRE/Feed-based floors is substantially better (but not 
dramatically more than 6%) for cement kilns and liquid fuel-fired 
boilers than the achievability under the emissions-based approach.
    \59\ Note that we considered using a floor methodology that 
simultaneously assesses all the pollutant emissions from each 
source. This methodology would define best performers as those 
sources with the best aggregate emissions across all (or a subset of 
all) the HAP and would perhaps more directly achieve the goal of 
obtaining a full suite of emission standards that are achievable by 
at least 6% of the sources. We rejected this approach in the 1999 
rule, since it could potentially result in least-common denominator 
source levels. See 64 FR at 52856. However, at least for 
incinerators and kilns, there is less potential concern with such a 
result because the Interim Standards have already reduced sources' 
emissions of all HAP considerably and the Interim Standards cap the 
level of floors for these sources. Nonetheless we may not have 
enough complete emissions information for all HAP for many source 
categories to adequately assess enough source's true ``aggregate 
emissions.'' See Section VI.G.
---------------------------------------------------------------------------

    We thus believe that using the SRE/Feed approach preferentially 
over the emissions-based approach and technology based approach is 
appropriate because use of the SRE/Feed approach results in floor 
levels that better reflect the range of emissions from well-designed 
and operated sources and also results in floor levels across all HAP 
that are achievable simultaneously by at least 6 percent of the sources 
within each source category.
    b. Why Do We Prefer the Air Pollution Control Technology Approach 
Over the Emissions-Based Approach? As previously discussed, we apply 
the air pollution control technology approach in two situations where 
we consider it inappropriate to directly assess hazardous waste feed 
control using an SRE/Feed type approach: the particulate matter 
standard for all source categories; and, the total chlorine standard 
for hydrochloric acid production furnaces. We discuss below why the 
emissions-based approach is not our preferred methodology for these 
standards.
    For particulate matter, the emissions-based approach identifies the 
lowest emitters as best performers, irrespective of the types of 
controls that were used. This would not necessarily reflect emissions 
that are in fact capable of being achieved by sources using MACT back-
end control technology as defined by the air pollution control 
technology approach because, as discussed above, our data are 
``snapshots'' of emissions from each source, obtained in one-time 
testing events. As a result, the particulate matter floors that are 
based on the emissions-based approach would not necessarily account for 
inherent variability such as ash feedrate fluctuation over time due to 
production process changes,\60\ uncertainties associated with 
correlations between operating parameter levels and emissions, 
precision and accuracy differences in different testing crews and 
analytical laboratories, and changes in emission of materials (SO 
2 being an example) that may cause test method 
interferences. The air pollution control technology approach may better 
account for this inherent variability because it assesses the emissions 
ranges from those sources that utilize the defined back-end MACT 
control devices, as opposed to merely selecting the lowest emitters 
irrespective of the type of control it uses.
---------------------------------------------------------------------------

    \60\ The emissions-based approach may not account for 
particulate matter emissions variability factors that are 
attributable to factors other than MACT control. For example, two 
sources with identical air pollution control devices could have 
different particulate matter emission concentrations merely because 
they process different types and amounts of raw material and/or 
nonhazardous waste fuels. From a MACT perspective, the source with 
the higher emissions would not be a poorer performer because feed 
control of raw material and nonhazardous waste fuels are not MACT 
floor controls.
---------------------------------------------------------------------------

    Also, using the emissions-based approach for incinerators and 
liquid boilers (for the particulate matter standard) and hydrochloric 
acid production furnaces (for the total chlorine standard) is not our 
preferred approach because it assesses in part, hazardous waste ash and 
chlorine feed control. As discussed above, the emissions-based approach 
defines best performers as those sources with the lowest emissions, and 
thus inherently accounts for and assesses hazardous waste ash and 
chlorine feed control in that sources with lower ash feedrates and 
chlorine feedrates may have lower emissions.\61\ This is not our 
preferred way of establishing floors for these HAP for the reasons 
discussed above in Section A.2.
---------------------------------------------------------------------------

    \61\ The best performers identified by the air pollution 
technology approach are less likely to be driven by low ash feeding 
facilities for the particulate matter standard because all the 
sources equipped with MACT-defined back-end control devices 
typically feed high levels of ash, thus we believe particulate 
matter emission levels from these sources are more a function of the 
air pollution control device control efficiency rather than the ash 
feed levels.
---------------------------------------------------------------------------

B. How Did EPA Select the Data To Represent Each Source When 
Determining Floor Levels?

    After we determine which MACT methodology is appropriate for a 
given pollutant and source category, we select which of the available 
emissions data to use for each source to: (1) Determine if 
subcategorization is warranted; (2)

[[Page 21229]]

identify the best performing sources; and (3) calculate the floor 
levels. Our emissions data base is complex because it includes, in 
part, compliance test data, emissions data that is representative of 
the normal operating range of the source, and, for the Phase I sources, 
multiple emission test data that have been collected over a number of 
years. See Part Two, Section III for more discussion on data base 
issues.
    We follow a general ``data hierarchy'' to determine which of these 
data types to use to represent each source's performance (with the 
performance being reassessed for each HAP). First, we prefer to 
explicitly use compliance test data rather than data representative of 
normal operations because compliance test data best reflect the upper 
range of emissions from each source and thus best accounts for day-to-
day emissions variability. Use of compliance test data allows us to 
express emission floors as ``short-term limits'' (e.g., hourly or 
twelve hour rolling averages), which is consistent with the current 
interim MACT standard format for incinerators, cement kilns, and 
lightweight aggregate kilns. Short-term limits are also consistent with 
the RCRA emission standards currently applicable to boilers and 
hydrochloric acid production furnaces. Finally, we prefer to use 
compliance test data because the majority of the available data are 
compliance test data.
    Absent sufficient compliance test data for sources within the 
source category to calculate floor levels, we default to explicitly 
using data that are representative of the source's operating range 
under conditions not designed to assess performance variability. Since 
these so-called normal data do not typically reflect the upper range of 
emissions from each source, we believe it is necessary to account for 
emissions variability (in part) by expressing floors that are based on 
normal data as long-term, annual average emission limits (since the 
snap-shot data, by definition, do not reflect short-term variability).
    We considered using all available emissions data to calculate the 
floors, irrespective of whether they were normal or compliance test 
data. We believe, however, that it is inappropriate to mix such 
dissimilar data when calculating floor levels because it would bring 
into question how to account for day-to-day emissions variability when 
setting the format of the standard. For example, if a floor were 
calculated using 50% percent normal data and 50% compliance data, 
should the standard be expressed as a long-term limit or short-term 
limit? This is critical because the averaging period associated with 
the numerical emission limitation affects the stringency of the 
standard. It is also unclear how mixing dissimilar data would affect 
the statistical variability factor we apply to each floor to assure 
that floor levels are achievable by the average of the best performing 
sources. As discussed in Part Two, Section VI.E, we apply the 
statistical variability factor to the floor levels to assure that the 
average of the best performing sources would be able to replicate the 
emission test results that were used to calculate the floor levels. 
Mixing dissimilar data not only complicates the analyses, but also 
could result in inconsistent evaluation of data (hence inconsistent 
results), primarily because the ratio of normal data to compliance data 
differs across HAP within each source and across all sources. We 
therefore believe it is appropriate to assess ``like data'' explicitly 
to assure results are consistent across HAP and source categories.
    We prefer to use the most recent compliance test data to represent 
each source in situations where we have data from multiple test 
campaigns that were collected at different times. For example, we 
typically have multiple test campaign emission information for cement 
kilns and lightweight aggregate kilns because: (1) We conducted a 
comprehensive data collection effort for these sources to update the 
data base that was used to support the 1999 final rule; and (2) these 
sources, prior to receiving their RCRA permit, are required to conduct 
emissions tests every three years.
    We believe it is appropriate to only use the most recent compliance 
test data for a source because those data best reflect current 
operations and emission levels. Older compliance test data may not be 
representative of current emissions because: (1) Permitted feed and air 
pollution control device operating levels may have been changed/
upgraded; (2) combustion unit and associated air pollution control 
equipment design may have been changed/upgraded; and (3) standard 
operating practices that relate to maintenance and upkeep may have been 
changed/upgraded. As a result, we believe that a source's most recent 
compliance data best reflect a source's upper range of emissions. We 
considered using all of the sources historical compliance emissions 
data to perhaps better account for day-to-day emissions variability. We 
believe, however, that it is not appropriate to consider older 
compliance emission test data to account for day-to-day emission 
variability because: (1) The older compliance data may reflect varying 
emissions merely because the source was previously operating with 
poorer control levels, which is not an appropriate factor to consider 
when assessing day-to-day emission variability; and (2) the most recent 
compliance test data adequately accounts for day-to-day variability 
because the operating levels demonstrated during the most recent 
compliance test generally represent the maximum upper range of 
operations and emissions.\62\
---------------------------------------------------------------------------

    \62\ Operating parameter limits are established based on 
compliance test operations to ensure emissions achieved during 
normal operations do not exceed the emissions that were demonstrated 
in the compliance test.
---------------------------------------------------------------------------

    We do not apply the concept of using the most recent emissions test 
information to normal emissions data (as previously discussed, we use 
normal emission data to calculate floor levels only in situations where 
we do not have sufficient compliance test data). We instead use all 
normal emissions data that are available because we are concerned that 
a source's most recent normal emissions may not be representative of 
its average emissions. The most recent normal emissions data could 
reflect emissions at the upper range of normal operations or the lower 
end of normal operations. If we were to use only the most recent normal 
emissions information, we may identify as best performers those sources 
that were operating below their average levels. This would be 
inappropriate because the floor level may be unachievable by the best 
performing sources.
    Finally, for liquid fuel-fired and solid fuel-fired boilers, we 
eliminated emission test runs from the MACT analysis when we had 
information that the source conducted sootblowing during that emission 
test run. Boilers that burn fuels with high ash content are designed to 
blow the soot off the tubes periodically to maintain proper heat 
transfer. The soot can contain metal HAP, and emissions of these HAP 
can increase during sootblowing. Although the current RCRA particulate 
matter and metals emissions standards for these sources at Sec. Sec.  
266.105 and 266.106 do not require sootblowing during compliance 
testing, we have provided guidance recommending that sources blow soot 
during one of the three runs of a compliance test condition and 
calculate average emissions considering the frequency and duration of 
sootblowing.\63\ We conclude that these sootblowing run data should not 
be

[[Page 21230]]

considered when establishing MACT floor, however, for several reasons. 
We do not know if all sources that blow soot followed the guidance to 
blow soot during a run of the test condition. If they did not, they 
could be identified as a best performer but may not be able to achieve 
the floor level when blowing soot. In addition, several boilers that 
blew soot during a run of the test condition did not use our 
recommended approach to calculate time-weighted average emissions 
considering the frequency and duration of sootblowing. For these 
sources, we cannot calculate time-weighted average emissions. We also 
note that, for sources with emission control equipment, emissions 
during sootblowing runs are not significantly higher than when not 
blowing soot. This is because soot particles are relatively large and 
easily controlled. For sources with no emission control equipment, 
sootblowing increased particulate matter emissions for some sources, 
but not others. In addition, we could not use the sootblowing run to 
help address emissions variability by evaluating run variability 
because the (in some cases) higher emissions during sootblowing are 
unrelated to the factors affecting run variability that we are 
evaluating (e.g., method precision and other largely uncontrollable 
factors that affect run-to-run emissions during a test condition). 
Finally, we note that the Agency did not propose to require sootblowing 
to demonstrate compliance with the MACT standards for industrial, 
commercial, and institutional boilers and process heaters.\64\ Although 
for these reasons we conclude that it is appropriate not to consider 
sootblowing run data to establish the MACT floor, we request comment on 
alternative views.\65\
---------------------------------------------------------------------------

    \63\ USEPA, ``Technical Implementation Document for EPA's Boiler 
and Industrial Furnace Regulations'' EPA530-R-92-011, March 1992, 
NTIS  PB92-154 947.
    \64\ See 68 FR 1660 (January 13, 2003).
    \65\ We note that a floor level considering sootblowing may be 
higher than a floor level based on discounting sootblowing runs.
---------------------------------------------------------------------------

    Because we do not consider sootblowing when establishing floor 
levels, sootblowing would not be required during performance testing to 
demonstrate compliance with the standards for particulate matter and 
semivolatile and low volatile metals.\66\
---------------------------------------------------------------------------

    \66\ The comparative risk assessment for this proposed rule did 
not evaluate the impact of sootblowing on average emissions. To 
ensure that RCRA permits are protective of human health and the 
environment, regulatory officials may determine that the effect of 
sootblowing on average emissions (i.e., considering the frequency 
and duration of sootblowing) should be considered in some 
situations, such as a source with uncontrolled or poorly controlled 
particulate emissions and with relatively high particulate matter or 
toxic metal emissions.
---------------------------------------------------------------------------

C. How Did We Evaluate Whether It Is Appropriate To Issue Separate 
Emissions Standards for Various Subcategories?

    The third step we use to calculate MACT floor levels evaluates 
subcategorization options. CAA section 112(d)(1) allows us to 
distinguish among classes, types, and sizes of sources within a 
category when establishing floor levels. Subcategorization typically 
reflects ``differences in manufacturing process, emission 
characteristics, or technical feasibility.'' See 67 FR 78058.
    We use both engineering principles and a statistical analysis to 
assess whether it is appropriate to subcategorize and issue separate 
emission standards. We first use engineering principles to determine 
potential subcategory options. These subcategory options are discussed 
in more detail in Part Two Section II for each source category. As 
discussed in greater detail below, we then determine if there is a 
statistical difference in the emission characteristics between these 
potential subcategory options. Finally, we conduct a technical analysis 
to determine if the statistical analysis results are consistent with 
sound engineering judgement.
    ``Analysis of Variance'' (ANOVA) is the statistical test used to 
cross-check these engineering judgements. ANOVA, a conventional 
statistical method, evaluates whether there are differences in the mean 
of HAP emissions levels from two or more different potential 
subcategories (i.e., do the different subcategories of HAP data come 
from distinctly different populations). Subcategories are considered 
significantly different using a 95% confidence level. ANOVA is used in 
combination with engineering principles to sequentially identify 
significant differences between various different combinations of 
potential subcategories. See U.S. EPA ``Draft Technical Support 
Document for HWC MACT Replacement Standards, Volume III: Selection of 
MACT Standards,'' March 2004, Chapter 4, for detailed steps and results 
of the ANOVA evaluation process.

D. How Did We Rank Each Source's Performance Levels To Identify the 
Best Performing Sources for the Three MACT Methodologies?

    The fourth step used in determining the MACT floor levels involves 
ranking each source's performance level to identify the best 
performers. Below we discuss the general ranking procedure used for 
each of the three MACT methodologies and the statistical methodology 
used to perform the ranking process.
1. Emissions-Based Methodology Ranking Procedure
    As previously discussed in Part Two, Section VI.A, the emissions-
based approach defines best performers as those sources with the lowest 
emissions in our database. Each source's emission test runs are first 
converted to an upper 99% confidence level in order to rank performance 
not only on the average emission levels each source achieves, but also 
on the emissions variability each source demonstrates during the 
emissions tests. We believe this is appropriate because a source's 
ability to consistently control its emissions below the MACT floor 
levels is important in determining whether a source is in fact a well 
designed and operated source.\67\ We then array and rank each source by 
its 99% upper confidence emission levels from best to worst (i.e., 
lowest to highest). For existing source floors, we identify the best 
performers as either sources at the 12th percentile ranking and below 
or the lowest 5 ranked sources values if we have data from less than 30 
sources. The best performing source for the new source floor is simply 
the source with the single lowest ranked 99% upper confidence emission 
level.
---------------------------------------------------------------------------

    \67\ For example, a source with average emissions of 100 and 
calculated variability of 10 would be ranked as a better performing 
source when compared to a source with average emissions of 100 and a 
calculated variability of 20.
---------------------------------------------------------------------------

2. SRE/Feed Ranking Procedure
    As previously discussed, the SRE/Feed methodology approach defines 
best performers as those sources with the best combined front-end 
hazardous waste feed control and back-end air pollution control 
efficiency as defined by our ranking procedure. The first step involves 
ranking each source's feed control level. As with the emissions-based 
approach, we first convert each source's feed control run levels (i.e., 
hazardous waste maximum theoretical emission concentration level or 
thermal feed concentrations) to an upper 99% confidence level. We then 
array each source's 99% upper confidence feed control levels from best 
to worst (i.e., lowest to highest). Next we assign a feed control 
ranking score to each source. The source with the lowest feed control 
value gets a ranking of 1, and the source with highest feed control 
value receives the highest numerical ranking.
    The second step ranks each source's system removal efficiency, 
which is a measure of the percent of metal or

[[Page 21231]]

chlorine that is emitted as compared to the amount fed to the 
combustion unit. Again, we first convert each source's system removal 
efficiency run values to an upper 99% confidence level value. We then 
array each source's 99% upper confidence levels from best to worst 
(i.e., highest to lowest). Next we assign a system removal efficiency 
ranking score to each source. The source with the best system removal 
efficiency gets a ranking of 1, and the source with the worst system 
removal efficiency receives the highest numerical ranking.
    As with the emissions ranking procedure discussed above, our feed 
control and system removal efficiency ranking procedure measures 
performance not only on the average feed control and system removal 
efficiency level each source achieves, but also on the feed and system 
removal efficiency variability each source demonstrates during the 
emissions tests. This is appropriate because a source's ability to 
consistently regulate its control mechanisms to achieve MACT emissions 
is important in determining whether a source is in fact a well designed 
and operated source.
    Third, we add each source's feed control ranking score and system 
removal efficiency ranking score together in order to calculate an 
aggregated SRE/Feed score. We then array and rank each source's 
aggregated score from best to worst (i.e., lowest to highest). For 
existing source floors, we identify the best performers as sources at 
the 12th percentile aggregate ranking and below or sources with the 
lowest 5 aggregated scores if we have data from less than 30 sources. 
The best performing source for the new source floor is simply the 
source with the single lowest aggregated score.
3. Technology Approach Ranking Procedure for the Particulate Matter 
Standard
    As previously discussed in Part Two, Section VI.A.2.a, the best 
performing sources for the particulate matter proposed floor levels are 
determined from a pool of sources that use the MACT-defining back-end 
control technology. We assess only the emissions from those sources 
equipped with the MACT-defining control technology (or technologies), 
and, as with the previously discussed methodologies, we convert each 
source's emission run values to an upper 99% confidence level value. 
Emissions information from each source is then grouped based on the 
type of MACT control each source uses. The first group contains 
emissions information from sources equipped with the best ranked MACT 
control device; the second group includes emissions information from 
sources equipped with the second best ranked MACT control technology 
(if there is more than MACT control technology), and so on.
    We then array and rank each source's 99% upper confidence emission 
levels from best to worst (i.e., lowest to highest) within each of 
these groups. If there is only one defined MACT control technology, the 
best performing sources are those sources with the lowest 99% upper 
confidence emission levels amongst the sources using this MACT control 
technology. The lowest emitting sources are added to a list of best 
performers up until the number of sources that are included in this 
list is representative of 12 percent of sources within the source 
category (for the existing source floor determination). If there is 
more than one defined MACT control technology, the list of best 
performers first considers sources with the lowest 99% upper confidence 
emission levels that are equipped with the best ranked control device 
up until the number of sources that are included in this list is 
representative of 12 percent of sources within the sources category. If 
additional sources need to be added to this list to appropriately 
represent 12% of the sources within the source category, then sources 
with the lowest emissions that are equipped with the second best MACT 
control device are added until the appropriate number of best 
performing sources are obtained.\68\ For the new source floor, the best 
performer is simply the single source equipped with the best ranked 
MACT control device with the lowest 99% upper confidence emission 
level.
---------------------------------------------------------------------------

    \68\ Note that this methodolgy does not base the floor on the 
highest emitting source amongst these best performers (as did the 
``expanded MACT pool'' did for 1999 rule). Rather, the floor is 
determined by calculating the average performance of all best 
performing sources.
---------------------------------------------------------------------------

4. Technology Approach Ranking Procedure for the Total Chlorine Floor 
for Hydrochloric Acid Production Furnaces
    As previously discussed in Part Two, Section VI.A.2.b, the 
technology approach used to determine the total chlorine floor levels 
for hydrochloric acid production furnaces defines best performers as 
those sources with the best total chlorine system removal efficiency. 
The ranking procedure used for this methodology is identical to that 
used in the emissions-based approach with the exception that system 
removal efficiencies are ranked instead of emissions. Each source's 
total chlorine system removal efficiency run values are first converted 
to an upper 99% confidence level. We then array and rank each source's 
99% upper confidence system removal efficiencies from best to worst 
(i.e., highest to lowest). For existing source floors, we define best 
performers as either: (1) Sources at the 12th percentile ranking and 
below; or (2) sources with the lowest 5 rankings if we have data from 
less than 30 sources. The best performing source for the new source 
floor is simply the source with the single highest 99% upper confidence 
system removal efficiency.
5. Description of the Statistical Procedures Used To Identify the 99% 
Confidence Levels
    As previously discussed, each source's performance level is first 
converted to an upper 99% confidence level in order to rank performance 
not only on the average performance level each source achieves, but 
also on the emissions variability each source demonstrates during the 
emissions tests. We believe this is appropriate because a source's 
ability to consistently control its emissions below the MACT floor 
levels is important in determining whether a source is in fact a well 
designed and operated source.
    Sources are ranked based on their projected ``upper 99% confidence 
limit'' (or lower 99% confidence limit for system removal efficiency). 
For emissions and feedrates, upper 99% confidence limits are determined 
using a ``prediction limit'' calculation procedure. The prediction 
limit is an estimate of the level which will capture 99 out of 100 
future test condition averages (where each average comprise three 
individual test runs). HAP emissions data within each source are 
determined to be normally distributed. The prediction limit is 
calculated for each source based on the average, standard deviation, 
and number of individual test runs.
    For system removal efficiencies, the lower 99% confidence limit is 
determined using the ``two parameter Beta distribution''. The beta 
distribution is used for modeling proportions, i.e., system removal 
efficiencies, is highly robust, and appropriately bounded by zero and 
1. Beta distribution modeling parameters are determined based on the 
``method of moments'' using the average and standard deviation of the 
individual source data. The lower 99% estimate comes directly from the 
Beta distribution model. See USEPA ``Draft Technical Support Document 
for HWC MACT Replacement Standards, Volume III: Selection of MACT 
Standards,''

[[Page 21232]]

March 2004, Chapter 8, for further discussion.

E. How Did EPA Calculate Floor Levels That Are Achievable for the 
Average of the Best Performing Sources?

    The emissions data we used to establish MACT floor were obtained by 
manual sampling of stack gas. To ensure that the average of the best 
performing sources can routinely achieve the floor during future 
performance testing under the MACT standards, we must account for 
emissions variability.
    We account for long-term emissions variability by: (1) Using 
compliance test emissions data, when available, to establish floors; 
(2) when other than compliance test data must be used to establish the 
floor, basing compliance on an annual average. In addition, we add a 
statistically-derived variability factor to the floor to account for 
run-to-run variability. This variability factor ensures that the 
average of the best performing sources can achieve the floor level in 
99 of 100 future tests if the best performing sources replicate the 
operating conditions and other factors that affect the emissions we use 
to represent the performance of those sources.
1. How Does Using Compliance Test Data Account for Variability?
    We use RCRA compliance test emissions data, when available, to 
establish the floors because compliance test data largely account for 
emissions variability. Under RCRA compliance testing, sources must 
establish operating limits based on operating conditions demonstrated 
during the test. Each source designs the compliance test such that the 
operating limits it establishes account for the variability of 
operating parameter levels it expects to encounter during its normal 
operations (e.g., feedrate of metals and chlorine; air pollution 
control device operating parameters, production rate). Thus, operating 
conditions during these tests generally reflect the upper range of 
emissions from these sources. Using a source's compliance test 
emissions to establish the floor accounts largely for long-term 
emissions variability. However, this does not necessarily account for 
factors that affect variability. As previously discussed, our snap-shot 
data base emissions information does not necessarily account for 
inherent variability such as feedrate fluctuation over time due to 
production process changes, uncertainties associated with correlations 
between operating parameter levels and emissions, precision and 
accuracy differences that may result from using different stack 
sampling crews and analytical laboratories, and changes in emission of 
materials (SO2 being an example) that may cause test method 
interferences.
    Use of compliance test data also does not account for run-to-run 
variability. We thus use a statistically-derived variability factor to 
account for the variability in emissions that would result if the best 
performing sources were to replicate their compliance tests, as 
discussed below.\69\
---------------------------------------------------------------------------

    \69\ EPA did not statistically assess run-to-run variability in 
the 1999 rule (although we noted that it existed; see 64 FR at 
52857. The reason is that by using the expanded MACT pool approach 
to account for variability (using surrogate sources from outside the 
best performing to assess the best performing sources' variability) 
we felt we had accounted for all such run-to-run variability. Id. 
Since we are not proposing to expand the MACT pool here, it is 
necessary to account for run-to-run variability by some other means.
---------------------------------------------------------------------------

    In addition, use of compliance test data may not account for long-
term variability of particulate matter emissions from sources equipped 
with a fabric filter. Accordingly, we also use a statistically-derived 
variability factor to account for this variability, as discussed below.
2. How Does Using Long-Term Averaging Account for Emissions Variability 
When Using Other Than Compliance Test Data?
    RCRA compliance test emissions data are not available for some 
metals (mercury in particular) for some source categories. In these 
cases, we use other emissions test data to establish the floor. These 
other test data are snap shots of emissions within the range of normal 
emissions. To largely account for emissions variability when using 
emissions data assumed to represent the average of normal emissions, we 
propose to express the floor as a long-term, yearly, average. Sources 
would comply with the floor by establishing limits on metal feedrate 
and air pollution control device operating parameters. Compliance with 
the metal feedrate limits would be based on an annual average feedrate, 
while compliance with the air pollution control device operating limits 
would be based on short-term limits (e.g., hourly rolling average). We 
propose short-term averages for air pollution control device operating 
parameters because the parameters may not correlate with emissions 
linearly; emissions resulting when an air pollution control device 
parameter is above the limit thus may not be offset by emissions 
resulting when the air pollution control device parameter is below the 
limit. See 1999 rule, 64 FR at 52920.
    As discussed above, we also use a statistically derived variability 
factor to account for the variability in emissions that would result if 
the best performing sources were to replicate the emissions tests we 
use to establish the floor, as discussed below.
    We use the normal emissions data to represent the average emissions 
from a source even though we do not know where the emissions may fall 
within the range of normal emissions; the emissions may be at the high 
end, low end, or close to the average emissions. It may be reasonable 
to assume the emissions represent average emissions, given that we have 
emissions data from several sources, and that emissions for these 
sources in the aggregate could be expected to fall anywhere within the 
range of normal emissions. Note that, as previously discussed, we have 
not applied the concept of using the most recent emissions test 
information to normal emissions data because we are concerned a 
source's most recent normal emissions may not be representative of a 
source's true average emissions. These emissions could reflect 
emissions at the upper range of normal operations, or instead, could 
reflect emissions at the lower end of normal operations. If we were to 
use only the most recent normal emissions information, the MACT 
standard setting process may identify best performers as those sources 
that operate below their normal levels. This may be inappropriate 
because the floor level may be unachievable even by the best performing 
sources. We invite comment as to whether floors that are based on 
normal data are in fact achievable by the best performing sources, and 
whether there is perhaps a more appropriate method to identify floors 
that are based on normal data.
3. What Statistical Procedures Did EPA Use To Calculate Floor Levels?
    In order to calculate a floor that would be achievable by the 
average of the best performing sources, we considered the variability 
in emissions across runs of the test conditions of the best performing 
sources. We also use statistical procedures to account for long-term 
variability in particulate matter emissions for sources equipped with 
fabric filters. We discuss these procedures and the rationale for using 
them below.
    a. Run-to-Run Variability. The MACT floor level is determined by 
modeling a normally distributed population that has an average and 
variability that are equal to that of the ``average'' of the best 
performing MACT pool sources. The MACT floor is calculated using a

[[Page 21233]]

modified prediction limit procedure. The prediction limit is designed 
to capture 99 out of 100 future three-run averages from the ``average'' 
of the best performing MACT sources.
    Specifically, the modified prediction limit for calculating the 
MACT floor is the sum of the average of the best performing sources and 
the ``pooled'' variability of the best performing sources. The pooled 
variability term accounts for the expected variability in future 
measurements due to variations resulting from system operation and 
measurement activities. The pooled variability term is based in part on 
the observed variance of individual runs within test conditions from 
the best performing MACT pool sources. The pooled variability term 
assumes that variability from the individual best performing sources 
are independent (not related), and thus are additive (and not 
averaged). The pooled variability term is a function of the variances 
of the individual MACT pool sources, the number of MACT pool sources, 
the desired 99% confidence level, and the number of future test runs 
for demonstrating compliance (assumed to be 3). See USEPA ``Draft 
Technical Support Document for HWC MACT Replacement Standards, Volume 
III: Selection of MACT Standards,'' March 2004, Chapter 7, for 
discussion of the detailed steps and prediction limit formula used to 
calculate the MACT floors.
    b. Particulate Matter Variability for Fabric Filters. Compliance 
test emissions of particulate matter from sources that are equipped 
with a fabric filter may not account for long-term variability because 
it is difficult to maximize emissions during the compliance test.\70\ 
Fabric filters control particulate matter emissions generally to the 
same concentration irrespective of the particulate matter loading at 
the inlet to the fabric filter. Because there are no operating 
parameters that can be readily changed to increase emissions, it is 
difficult to maximize emissions of particulate matter from a fabric 
filter during compliance testing.\71\
---------------------------------------------------------------------------

    \70\ We note that semivolatile and low volatile metal emissions, 
however, can be maximized during compliance testing for sources 
equipped with a fabric filter. Metals may be spiked in the hazardous 
waste feed to levels that account for long-term feedrate 
variability. Although the particulate matter emission concentration 
would not be expected to increase during a metals compliance test 
for a source equipped with a fabric filter, the semivolatile and low 
volatile metals emissions concentrations would increase. This is 
because the concentration of metals in the emitted particulate 
matter would increase.
    \71\ We note that this situation is unique for fabric filters. 
Sources equipped with other control devices--electrostatic 
precipitators, ionizing wet scrubbers, and wet scrubbers--can 
readily change the device's operating conditions (e.g., power input 
to an electrostatic precipitator; pressure drop across a wet 
scrubber) during compliance testing to ``detune'' collection 
efficiency and increase emissions. In addition, these other control 
devices provide ``percent reduction'' control of pollutants whereby 
as inlet loading increases, emission concentrations also increase. 
Thus, increasing the inlet loading (e.g., by spiking the ash 
feedrate to an incinerator) even without detuning the control device 
would also increase emissions of particulate matter for devices 
other than a fabric filter.
---------------------------------------------------------------------------

    To address long-term variability in particulate matter emissions 
for fabric filters we developed a universal variability factor (UVF). 
The UVF represents the standard deviation of the pooled runs from 
multiple compliance tests for a source, and is imputed as a function of 
the source's emission concentration. We use the UVF to account for both 
long-term and run-to-run variability to calculate the floor using the 
procedures discussed above in lieu of the pooled variability term for 
the most-recent test condition run variability.
    To develop the data base to calculate the UVF, we considered each 
best performing source that is equipped with a fabric filter and for 
which we have two or more compliance tests for particulate matter. We 
considered all compliance test particulate matter emissions data for 
these sources, including those test conditions we previously labeled as 
``IB'' (representing in-between), indicating that emissions levels are 
lower than for another test condition of the compliance test campaign. 
We include historical test campaign data where available for 
incinerators, cement kilns, and lightweight aggregate kilns. 
Considering historical compliance test data and compliance test data 
labeled IB is appropriate because any differences in emission levels 
(over time or among compliance test results for a test campaign) should 
be indicative of emissions variability given that fabric filters 
generally produce constant emission concentrations and are difficult to 
detune to increase emissions for compliance testing. Finally, we 
combined test conditions for multiple on-site sources where both the 
combustor and fabric filter have similar design and operating 
characteristics. Combining the test conditions for such sources as if 
they represent emissions from a single source better accounts for 
emissions variability.
    To calculate the UVF, we calculated the pooled standard deviation 
of the runs for each source for which we have data for two or more 
compliance tests and plotted this standard deviation versus particulate 
matter emission concentration for all such sources. It is reasonable to 
aggregate the data for sources across all source categories given that 
there is no reason to believe that the standard deviation/emissions 
relationship would vary from source category to source category. We 
then identified the best-fit curve for the data. The best fit curve is 
a power function that achieved a R2 of 0.83, indicating a 
good power function correlation between standard deviation and emission 
concentration.\72\
---------------------------------------------------------------------------

    \72\ The procedure we use to identify the universal variability 
factor for particulate matter emissions for sources equipped with 
fabric filters is discussed in detail in USEPA, ``Draft Technical 
Support Document for HWC MACT Replacement Standards, Volume III: 
Selection of MACT Standards,'' March 2004, Chapter 5.3. Please note 
that we consider alternative approaches to identify the universal 
variability factor as discussed in the technical support document, 
and request comment on those alternatives.
---------------------------------------------------------------------------

    We use the best-fit curve to impute a standard deviation for each 
best performing source (that is equipped with a fabric filter) as a 
function of the source's particulate matter emissions. We use the 
source's average compliance test emissions (i.e., including historical 
compliance test emissions that we label in the data base as ``WC'' and 
``IB'') to represent average emissions.

F. Why Did EPA Default to the Interim Standards When Establishing 
Floors?

    When we calculate floor levels for several standards for the Phase 
I sources, the floor levels would be higher than the currently 
applicable interim standards at Sec. Sec.  63.1203, 63.1204, and 
63.1205. As explained earlier, we conclude that today's proposed floor 
levels can be no higher than the interim standards because all sources, 
not just the best performing sources, are achieving the interim 
standards. The most recent emissions data in our data base are from 
compliance testing in 2001 and do not represent emissions tests from 
sources used to demonstrate compliance with the interim standards, thus 
the data we used to calculate the proposed floor levels generally does 
not reflect the control upgrades necessary for compliance with the 
interim standards. The fact that we are ``capping'' the floor at the 
interim standard level does not mean our proposed methodology is less 
conservative than the methodology used in the 1999 rule. Our calculated 
floor levels can be higher than the interim standards for several 
reasons. As a result of our data collection effort, we have compiled 
more emissions information from some source categories that result in 
higher calculated floor levels (e.g., dioxin/furans for lightweight 
aggregate

[[Page 21234]]

kilns). Some of the instances where we ``capped'' the floor at the 
interim standard level occurred when the interim standard was a beyond-
the-floor standard promulgated in 1999 (e.g., semivolatile metals for 
lightweight aggregate kilns). Finally, some standards are ``capped'' 
because we used different types of data to calculate the proposed 
floors (e.g., the 1999 rule generally considered normal mercury data to 
establish the mercury floor for incinerators, whereas today's proposed 
approach used compliance test data to calculate the mercury floor).

G. What Other Options Did EPA Consider?

    We considered five other alternative approaches to establish the 
full suite of floor levels for each source category. The first two 
alternative options use different combinations of the three main 
methodology options to determine the proposed floors. Note that we also 
conducted a complete economics and benefits analysis for these first 
two alternative options. See USEPA ``Draft Technical Support Document 
for HWC MACT Replacement Standards, Volume V: Emission Estimates and 
Engineering Costs,'' March, 2004 for more information. The third option 
identifies best performing sources by considering emissions of metals 
and particulate matter simultaneously, instead of pollutant by 
pollutant. The fourth option is an approach recommended by the 
Environmental Treatment Council. Finally, the fifth option identifies 
best performing sources as those sources with the best back-end control 
efficiencies, as measured by their associated system removal 
efficiencies. After review of comments we may use one or more of these 
approaches in toto or part to establish final standards. We explain 
below how these approaches work and the rationale for considering them.
1. What Is Alternative Option 1, and What Is the Rationale?
    Under alternative option 1, we do not use the SRE/Feed methodology 
to calculate any floors. We use the emissions-based approach to 
establish all the floors, other than the exceptions that are explained 
below. We express emission standards for energy recovery units in units 
of hazardous waste thermal emissions when appropriate. All other 
emission standards under this approach are expressed as stack gas 
emission concentrations. The two exceptions under this option uses the 
technology-based approach for the particulate matter standard (for all 
source categories) and the total chlorine standard for hydrochloric 
acid production furnaces, as was done for today's proposed standards.
    We evaluated this option because it is simpler and more 
straightforward to use than the SRE/Feed Approach. The best performing 
sources simply are those with the lowest emissions in our data base, 
irrespective of the level of feed control or back-end control a source 
achieves. The advantages of using the air pollution control technology 
approach and expressing emission standards using the hazardous waste 
thermal emissions format for energy recovery units are retained. 
Although we have doubts that standards based on these limits are 
achievable even by the best performing sources (as noted earlier) and 
that this approach could be based on unrepresentatively low hazardous 
waste feedrates, we invite comment as to whether this approach is 
appropriate. We present the results of using alternative option 1 to 
identify floor levels for existing sources in Table 3 below. See U.S. 
EPA ``Draft Technical Support Document for HWC MACT Replacement 
Standards, Volume III: Selection of MACT Standards,'' March 2004, 
Chapters 16, 17, and 18 for documentation of the floor levels.

                                         Table 3.--Floor Levels for Existing Sources Under Alternative Option 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                       Hydrochloric acid
                                     Incinerators        Cement kilns         Lightweight      Solid fuel-fired    Liquid fuel-fired      production
                                                                            aggregate kilns       boilers \1\         boilers \1\        furnaces \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dioxin/Furans (ng TEQ/dscm).....  0.28 for dry APCD   0.20 or 0.40 +      0.20 or 400[deg]F   CO or THC standard  3.0 or 400[deg]F    CO or THC standard
                                   and WHB             400[deg]F at APCD   at kiln             as a surrogate.     at APCD inlet for   as a surrogate.
                                   sources,\6\ 0.20    inlet.\7\           outlet.\7\                              dry APCD sources;
                                   or 0.40 +                                                                       CO or THC
                                   400[deg]F at APCD                                                               standard as
                                   inlet for                                                                       surrogate for
                                   others.\7\                                                                      others.
Mercury.........................  130 [mu]g/dscm \7\  31 [mu]g/dscm \2\.  19 [mu]g/dscm \2\.  10 [mu]g/dscm.....  3.7E-6 lb/MMBtu 2,  Total chlorine
                                                                                                                   5.                  standard as
                                                                                                                                       surrogate.
Particulate Matter..............  0.015 gr/dscf \7\.  0.028 gr/dscf.....  0.025 gr/dscf \7\.  0.063 gr/dscf.....  0.032 gr/dscf.....  Total chlorine
                                                                                                                                       standard as
                                                                                                                                       surrogate.
Semivolatile Metals (lead         19 [mu]g/dscm.....  1.3E-4 lb/MMBtu     3.1E-4 lb/MMBtu     170 [mu]g/dscm....  1.1E-5 lb/MMBtu 2,  Total chlorine
 +cadmium).                                            \5\.                \5\ and 250 [mu]g/                      5.                  standards as
                                                                           dscm.\3\                                                    surrogate.
Low Volatile Metals (arsenic +    14 [mu]g/dscm.....  1.1E-5 lbs/MMBtu    9.5E-5 lb/MMBtu     210 [mu]g/dscm....  7.7E-5 lb/MMBtu 4,  Total chlorine
 beryllium + chromium).                                \5\.                \5\ and 100 [mu]g/                      5.                  standard as
                                                                           dscm.\3\                                                    surrogate.
Total Chlorine (hydrogen          0.93 ppmv.........  41 ppmv...........  600 ppmv \7\......  440 ppmv..........  5.7E-3 lb/MMBtu     14 ppmv or
 chloride + chlorine gas).                                                                                         \5\.                99.9927% system
                                                                                                                                       removal
                                                                                                                                       efficiency.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Particulate matter, semivolatile metal, low volatile metal, and total chlorine standards apply to major sources only for solid fuel-fired boilers,
  liquid fuel-fired boilers, and hydrochloric acid production furnaces.
\2\ Standard is based on normal emissions data.
\3\ Sources must comply with both the thermal emissions and emission concentration standards.
\4\ Low volatile metal standard for liquid fuel-fired boilers is for chromium only. Arsenic and beryllium are not included in the low volatile metal
  total for liquid fuel-fired boilers.
\5\ Standards are expressed as mass of pollutant contributed by hazardous waste per million Btu contributed by the hazardous waste.
\6\ APCD denotes ``air pollution control device,'' WHB denotes ``waste heat boiler.''

[[Page 21235]]

 
\7\ Floor level represents the ``capped interim standard level,'' which means the floor level determined by the associated methodology was less
  stringent than the interim standard level.

2. What Is Alternative Option 2, and What Is the Rationale?
    Under alternative option 2, we use the emissions-based approach to 
establish all floors and there are no exceptions. All floor levels are 
expressed in units of stack gas concentrations (we do not express any 
floors for energy recovery units in terms of thermal emissions). The 
best performing sources for all floors are those with the lowest 
emissions, on a stack gas concentration basis.
    We are not proposing this alternative option because it has the 
disadvantages that the more complicated provisions of Option 1 (and to 
some extent Option 2) address: (1) By not using the SRE/Feed Approach 
for metals and total chlorine, it does not ensure that sources could 
use either feedrate control or back-end control to achieve the floor; 
(2) the approach may be inappropriately biased against sources that 
burn hazardous waste fuel at high firing rates because it does not 
express the standards in units of hazardous waste thermal emissions; 
(3) it inappropriately considers feed control for particulate matter 
and for hydrochloric acid production furnaces by not using the Air 
Pollution Control Device Approach for those floors; and (4) it may not 
appropriately estimate the performance of the average of the 12 percent 
best performing sources given that those best performers may have low 
emissions in part because their raw material and/or fossil fuels 
contained low levels of HAP during the emissions test (and because we 
do not believe feed control of HAP in raw material and fossil fuel 
should be assessed as a MACT floor control because it could result in 
floor levels that are not replicable by the best performing sources, 
nor duplicable by other sources).
    We invite comment as to whether this alternative approach is 
appropriate, noting the doubts we have voiced above. We present the 
results of using this alternative option 2 to identify floor levels for 
existing sources in Table 4 below. See USEPA ``Draft Technical Support 
Document for HWC MACT Replacement Standards, Volume III: Selection of 
MACT Standards,'' March 2004, Chapter 16, for more information.

                                         Table 4.--Floor Levels for Existing Sources Under Alternative Option 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                       Hydrochloric acid
                                     Incinerators        Cement kilns         Lightweight      Solid fuel-fired    Liquid fuel-fired      production
                                                                            aggregate kilns        boilers 1           boilers 1          furnaces 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dioxin/Furans (ng TEQ/dscm).....  0.28 for dry APCD   0.20 or 0.40 +      0.20 or 400[deg]F   CO or THC standard  3.0 or 400[deg]F    CO or THC standard
                                   and WHB sources;    400[deg]F at APCD   at kiln             as a surrogate.     at APCD inlet for   as a surrogate.
                                   5 0.20 or 0.40 +    inlet.6             outlet.\6\                              dry APCD sources;
                                   400[deg]F at APCD                                                               CO or THC
                                   inlet for                                                                       standard as
                                   others.6                                                                        surrogate for
                                                                                                                   others.
Mercury.........................  130 [mu]g/dscm 6..  31 [mu]g/dscm 2...  19 [mu]g/dscm 2...  10 [mu]g/dscm.....  0.47 [mu]g/dscm 2.  Total chlorine
                                                                                                                                       standard as
                                                                                                                                       surrogate.
Particulate Matter..............  0.0040 gr/dscf....  0.016 gr/dscf.....  0.025 gr/dscf 6...  0.065 gr/dscf.....  0.0028 gr/dscf....  Total chlorine
                                                                                                                                       standard as
                                                                                                                                       surrogate.
Semivolatile Metals (lead +       19 [mu]g/dscm.....  68 [mu]g/dscm.....  130 [mu]g/dscm....  170 [mu]g/dscm....  8.7 [mu]g/dscm 2..  Total chlorine
 cadmium).                                                                                                                             standard as
                                                                                                                                       surrogate.
Low Volatile Metals (arsenic +    14 [mu]g/dscm.....  8.9 [mu]g/dscm....  82 [mu]g/dscm.....  210 [mu]g/dscm....  28 [mu]g/dscm 4...  Total chlorine
 beryllium + chromium).                                                                                                                standards as
                                                                                                                                       surrogate.
Total Chlorine (hydrogen          0.93 ppmv.........  41 ppmv...........  600 ppmv 6........  440 ppmv..........  2.4 ppmv..........  2.0 ppmv.
 chloride + chlorine gas).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
1 Particulate matter, semivolatile metal, low volatile metal, and total chlorine standards apply to major sources only for solid fuel-fired boilers,
  liquid fuel-fired boilers, and hydrochloric acid production furnaces.
2 Standard is based on normal emissions data.
3 Sources must comply with both the thermal emissions and emission concentration standards.
4 Low volatile metal standard for liquid fuel-fired boilers is for chromium only. Arsenic and beryllium are not included in the low volatile metal total
  for liquid fuel-fired boilers.
5 APCD denotes ``air pollution control device'', WHB denotes ``waste heat boiler'.
6 Floor level represents the ``capped interim standard level'', which means the floor level determined by the associated methodology was less stringent
  than the interim standard level.

3. What Is Alternative Option 3, and What Is the Rationale?
    Under alternative option 3, we evaluated an approach to identify 
the best performing sources for particulate matter, semivolatile 
metals, and low volatile metals that considers how well a source is 
controlling these pollutants simultaneously. Simultaneous control of 
these pollutants is an appropriate consideration because these 
pollutants are controlled by the same emission control device, the 
particulate matter control device (e.g., a wet scrubber, electrostatic 
precipitator, or fabric filter). We call this alternative approach the 
Simultaneous Achievability for Particulates (SAP) Approach. See USEPA, 
``Draft Technical Support Document for HWC MACT Replacement Standards, 
Volume III: Selection of MACT Standards,'' March 2004, Chapters 10 and 
19.

[[Page 21236]]

    We evaluated semivolatile metal and low volatile metal emissions 
for energy recovery sources--cement kilns, lightweight aggregate kilns, 
and liquid fuel-fired boiler--under two emissions-based SAP 
alternatives: hazardous waste thermal emissions, and stack gas 
concentrations. The hazardous waste thermal emissions option assesses 
semivolatile metal and low volatile metal thermal emissions for energy 
recovery units, while assessing particulate matter using the emissions-
based stack gas concentration approach. The emissions-based stack-gas 
concentration approach assesses stack gas concentrations (as opposed to 
thermal emissions) for all HAP. Note that we did not evaluate 
hydrochloric acid production furnaces under this SAP approach because 
we propose to use the total chlorine standard as a surrogate to control 
emissions of particulate matter and metals for these sources.
    Under the SAP approach, we rank emissions for each pollutant across 
the sources for which we have emissions data for that pollutant. For 
ranking, we use the upper 99% confidence interval for the average of 
the runs of the test condition for a source. For example, if we have 
semivolatile metal emissions data for 15 sources, the lowest 
semivolatile metal emissions level is ranked one and the highest is 
ranked 15. To identify the best performing sources for all three 
pollutants simultaneously, we calculate an aggregate rank score for 
each source. For example, if source A has a rank of 5 for particulate 
matter, a rank of 10 for semivolatile metals, a rank of 15 for low 
volatile metals, the aggregate rank score for that source is 10, the 
average rank across the pollutants. If we do not have emissions data 
for a pollutant for a source, there is no rank score for that 
pollutant, and that pollutant is not considered in the aggregate rank 
score for the source.
    To identify the best performing sources in the aggregate, we rank 
the aggregate rank scores for the sources from lowest to highest. If we 
have emissions data for all three pollutants for all sources, the 5 (or 
12% if we have data for more than 30 sources) sources with the lowest 
aggregate rank scores are the best performing sources. If we have 
incomplete data sets for some sources for a source category, the best 
performing sources for a pollutant (i.e., particulate matter, 
semivolatile metals, or low volatile metals) are the sources with the 
lowest aggregate rank scores and for which we have emissions data.
    We present the alternative MACT floors for existing sources under 
the SAP approach in Table 5 below.

                       Table 5.--Floor Levels for Existing Sources Under the SAP Approach
----------------------------------------------------------------------------------------------------------------
                                                          Particulate
         Source category              Emissions-based    matter floor   Semivolatile metals  Low volatile metals
                                         approach          (gr/dscf)           floor                floor
----------------------------------------------------------------------------------------------------------------
Incinerators.....................  Stack Gas Conc......        0.0040  53 [mu]g/dscm.......  50 [mu]g/dscm.
Cement Kilns.....................  Thermal Emissions...        0.027   190 lb/trillion Btu.  20 lb/trillion Btu.
                                   Stack Gas Con.......        0.015   103 [mu]g/dscm......  14 [mu]g/dscm.
Lightweight Aggregate Kilns......  Thermal Emissions...        0.019   300 lb/trillion Btu.  95 lb/trillion Btu.
                                   Stack Gas Conc......        0.019   120 [mu]g/dscm......  89 [mu]g/dscm.
Solid Fuel-Fired Boilers.........  Stack Gas Conc......        0.090   180 [mu]g/dscm......  230 [mu]g/dscm.
Liquid Fuel-Fired Boilers........  Thermal Emissions...        0.0039  81 lb/trillion Btu..  180 lb/trillion
                                                                                              Btu.
                                   Stack Gas Conc......        0.0039  26 [mu]g/dscm.......  210 [mu]g/dscm.
----------------------------------------------------------------------------------------------------------------

    We request comment on this alternative approach for identifying 
MACT floors. If we use this approach in the final rule to identify MACT 
floors, we would promulgate a beyond-the-floor standard for particulate 
matter of 0.030 gr/dscf for existing solid fuel-fired boilers for the 
same reasons we are proposing today a beyond-the-floor standard. See 
Part Two, Section X.C for a discussion of today's proposed beyond-the-
floor particulate matter standard for solid fuel-fired boilers.
    See USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards,'' March 
2004, Chapters 10 and 19, for a more detailed explanation of this SAP 
analysis.
4. What Is Alternative Option 4, and What Is the Rationale?
    The Environmental Technology Council (ETC) recommends an approach 
to calculate floor levels for metals and chlorine that uses a low 
feedrate screen and addresses emissions variability differently than 
the options we evaluated.\73\ We may use this approach in total or in 
part to support a final rule, and therefore request comment on the 
approach.
---------------------------------------------------------------------------

    \73\ Update on MACT Floor Evaluations Revised Data Base, 
Environmental Technology Council, February 2003.
---------------------------------------------------------------------------

    Under ETC's approach, test conditions are screened from further 
consideration if metals or chlorine were not fed at levels that 
challenge the emissions control system.\74\ Feedrates of metals and 
chlorine in hazardous waste are normalized to account for size of the 
combustor by converting feedrates to maximum theoretical emissions 
concentrations. A low maximum theoretical emissions concentration 
filter is used to screen out emissions from low feed test conditions, 
where the filter is the lower 99% confidence limit of the mean of the 
maximum theoretical emissions concentrations for all test conditions 
for all sources within a source category.
---------------------------------------------------------------------------

    \74\ This approach therefore identifies a de minimis feed 
control level for each source category and does not evaluate 
emissions from these de minimus feeders in the MACT analysis because 
these de minimis feed control levels may not be feasible for other 
sources to duplicate. The screen is performed individually by 
pollutant so that if semivolatile metals were fed at rates that 
challenged the emissions control system but low volatile metals were 
not, only the low volatile metal emissions data for that test 
condition would be screened from further analysis.
---------------------------------------------------------------------------

    ETC's approach also excludes specialty units, defined as sources 
that burn munitions and radiological waste (i.e., Department of Defense 
and Department of Energy sources). ETC believes that these sources burn 
wastes with atypical concentrations of ash and metals that may 
inappropriately skew the calculation of floor levels. Under this 
approach, we would either subcategorize and issue separate emission 
standards for these specialty units, or omit these speciality units 
from the MACT analysis and require the specialty units to comply with 
the floor levels that are determined from emissions of the non-
specialty units.
    After applying the low maximum theoretical emissions concentration 
filter and excluding specialty units, this approach identifies the best 
performing sources by ranking emissions from

[[Page 21237]]

lowest to highest.\75\ Run variability is not considered at this point. 
For incinerators, cement kilns, and lightweight aggregate kilns where 
we may have historical compliance test emissions from several test 
campaigns for a source, test conditions from the campaign with the 
lowest compliance test emissions are used to identify the best 
performers.
---------------------------------------------------------------------------

    \75\ This low feed screen is not applied to cement kilns and 
lightweight aggregate kilns for the particulate matter standard 
because ash feedrate is not considered to be a dominant factor that 
influences particulate matter emissions (rather, particulate matter 
emissions are more a function of the back-end control device 
efficiency).
---------------------------------------------------------------------------

    The average of the emissions from the best performing sources are 
used to calculate the floor, and an emissions variability factor is 
added. For incinerators, cement kilns, and lightweight aggregate kilns 
where we may have historical compliance test emissions data from 
several test campaigns for a source, three approaches are considered to 
select representative emissions for each best performing source: (1) 
The highest compliance test emissions from any test campaign; (2) the 
average of the highest compliance test emissions from all test 
campaigns; and (3) the highest emissions during the most recent 
compliance test campaign. By identifying the best performers based on 
compliance test emissions from the test campaign with the lowest 
emissions and calculating the floor using compliance test emissions 
under these alternative approaches, emissions variability is addressed 
in part.\76\
---------------------------------------------------------------------------

    \76\ This approach for partially accounting for emissions 
variability is effective only for those incinerators, cement kilns, 
and lightweight aggregate kilns for which we have emissions data for 
more than one test campaign.
---------------------------------------------------------------------------

    Emissions variability is accounted for by adding an emissions 
variability factor to the average emissions for the best performing 
sources. The variability factor is a measure of the average run-to-run 
variability for the test conditions for the best performing sources. 
The variability factor is determined as the upper confidence limit 
(calculated at the 99% confidence interval) around the mean of the runs 
for each test condition for each best performer. (For sources with more 
than one compliance test condition, the variability factor for each 
source is first determined as the average of the variabilities 
associated with each compliance test condition).\77\ The upper 
confidence limits are averaged across the best performing sources, and 
the average confidence limit is added to the average emissions from the 
best performers to identify the floor.
---------------------------------------------------------------------------

    \77\ We do not use this step in our statistical analysis because 
we identify one test condition only as being representative of the 
emissions for each source. Alternatively, ETC's approach includes an 
option where the average of the historical compliance test 
conditions is considered for Phase I sources. Under this option, 
ETC's approach considers the average run-to-run variability for 
those historical compliance tests.
---------------------------------------------------------------------------

    We invite comment as to whether this alternative approach is 
appropriate. We calculated alternative floor levels for new and 
existing sources with minor adjustments.\78\ We present the results of 
applying that approach in Table 6 below. See USEPA ``Draft Technical 
Support Document for HWC MACT Replacement Standards, Volume III: 
Selection of MACT Standards,'' March 2004, Chapters 12 and 21, for more 
information on how we applied this approach to our data base.
---------------------------------------------------------------------------

    \78\ Note that we modified part of ETC's suggested methodology 
in some instances, which has resulted in our calculated floor levels 
to differ from ETC's calculated floor levels. These modifications 
are discussed in USEPA ``Draft Technical Support Document for HWC 
MACT Replacement Standards, Volume III: Selection of MACT 
Standards,'' March 2004, Chapter 12.

                                       Table 6.--Floor Levels for Existing Sources Under the Modified ETC Approach
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                          Incinerators
                                                                   --------------------------                     Lightweight   Solid fuel-  Liquid fuel-
                                                 Data base                        Excluding     Cement kilns       aggregate       fired        fired
                                                                        All       speciality                         kilns        boilers      boilers
                                                                                    units
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mercury ([mu]g/dscm)...................  Avg of historical CT data    130 (308)    130 (308)                48              37  ...........  ...........
                                                                            \1\          \1\
                                         Most recent CT data......    130 (308)    130 (308)                40              31           14          4.8
                                                                            \1\          \1\
                                         Highest of historical CT     130 (308)    130 (308)                68              45  ...........  ...........
                                          data.                             \1\          \1\
----------------------------------------
Particulate Matter (gr/dscf)...........  Avg of historical CT data       0.0043       0.0043             0.025           0.017  ...........  ...........
                                         Most recent CT data......       0.0043       0.0043             0.025           0.017         0.11       0.0090
                                         Highest of historical CT        0.0043       0.0043     0.030 (0.032)           0.017  ...........  ...........
                                          data.                                                            \1\
----------------------------------------
Semivolatile Metals ([mu]g/dscm).......  Avg of historical CT data           53           32               230   250 (901) \1\  ...........  ...........
                                         Most recent CT data......           53           32               160   250 (746) \1\          230          8.2
                                         Highest of historical CT            53           32               300  250 (1208) \1\  ...........  ...........
                                          data.
----------------------------------------
Low Volatile Metals ([mu]g/dscm).......  Avg of historical CT data           39           46                51   110 (119) \1\  ...........  ...........
                                         Most recent CT data......           39           36                42   110 (129) \1\          320           52
                                         Highest of historical CT            39           56            56 \1\   110 (133) \1\  ...........  ...........
                                          data.
----------------------------------------
Total Chlorine (ppmv)..................  Avg of historical CT data          1.4          1.8                85  600 (1655) \1\  ...........  ...........
                                         Most recent CT data......          1.4          1.8                86  600 (1811) \1\          410          3.2
                                         Highest of historical CT           1.4          1.8                89  600 (1823) \1\  ...........  ...........
                                          data.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: ``CT'' means Compliance Test.
 

[[Page 21238]]

 
\1\ Floor would be capped by the Interim Standards. Number in parentheses represents the calculated floor level, the number preceding is the ``capped''
  interim standard level.

5. What Is Alternative Option 5, and What Is the Rationale?
    Alternative Option 5 would use system removal efficiency (SRE) to 
identify the best performing sources for the mercury, semivolatile 
metals, low volatile metals, and total chlorine floor levels. This is 
similar to the approach we propose to establish the total chlorine 
standard for hydrochloric acid production furnaces. See discussion in 
Part Two, Section VI.A.2.b.
    Floor levels would be expressed as an SRE or an emission 
concentration where the emission concentration is based on the 
emissions achieved by the best performing SRE sources.\79\ A source 
could elect to comply with either floor. An emissions floor as an 
alternative to the SRE floor is appropriate because a source may be 
achieving emission levels lower than those achieved by the best 
performing SRE sources even though it may not be achieving MACT floor 
SRE. For example, a source may be achieving low emissions without 
achieving MACT SRE by using superior feedrate control.
---------------------------------------------------------------------------

    \79\ We note that an SRE option, in some form, could be added to 
any of the emission-based approaches previously discussed.
---------------------------------------------------------------------------

    The SRE floor is an SRE that the average of the best performing SRE 
sources could be expected to achieve in 99 of 100 future tests when 
operating under the conditions used to establish the SRE.\80\ The 
emissions floor is a stack gas concentration, or thermal emission 
concentration for source categories that burn hazardous waste fuels, 
that the average of the best performing SRE sources could be expected 
to achieve in 99 of 100 future tests when operating under the 
conditions used to establish the SRE and emission level.
---------------------------------------------------------------------------

    \80\ Note that we only considered SREs associated with emission 
values designated as compliance test (CT) in the database. See USEPA 
``Draft Technical Support Document for HWC MACT Replacement 
Standards, Volume III: Selection of MACT Standards,'' March 2004, 
Chapters 11 and 20, for more information.
---------------------------------------------------------------------------

    We note that this approach is not applicable for situations where 
sources in a source category do not use back-end control to control 
metals or total chlorine. For example, cement kilns do not use back-end 
control to control mercury or total chlorine.\81\
---------------------------------------------------------------------------

    \81\ Although the alkalinity in cement kiln raw materials helps 
control total chlorine emissions, we are concerned that the system 
removal efficiencies achieved may not be readily reproducible.
---------------------------------------------------------------------------

    This approach is also not applicable for situations where our data 
base is comprised of normal emissions data. As discussed previously, 
SREs calculated from normal test conditions may be unreliable because a 
small error in the feedrate calculation at low feedrates can have a 
substantial impact on the calculated SRE.
    In situations where this SRE-based approach is not applicable, we 
would use an alternative approach to identify MACT floor, such as the 
Emissions approach.
    Floor levels for existing sources under this approach are presented 
in Table 7.
    We also investigated a variation of this approach where sources 
with atypically high feedrates for metals or chlorine are excluded from 
the calculation of the alternative emission level. This variation may 
be appropriate to ensure that sources with high feedrates do not drive 
the alternative emission concentration-based floor inappropriately high 
even though the source may be a best performing SRE source. Under this 
variation, note that sources with high feedrates are used, however, to 
identify the best performing SRE sources and MACT SRE. This is because 
sources with the highest feedrates may employ the best performing back-
end control systems to meet current standards or otherwise control 
emissions. As a measure of atypically high feedrates, we use the 99th 
upper percentile feedrate around the mean of feedrate data in the data 
set available for the analysis. To ensure that we continue to use 5 
sources or 12 percent of sources to calculate the emission 
concentration-based floor under this variation, we replace a best 
performing SRE source that is screened out of the concentration-based 
floor analysis because of high feedrates with the source with the next 
best SRE.\82\
---------------------------------------------------------------------------

    \82\ Since sources with atypically high feedrates may still have 
low emissions, sources with hazardous waste feed control levels 
above the threshold are flagged, but not immediately removed from 
the data set. Sources' SREs are ranked from best to worst, initially 
choosing the best ranked 5 or 12% of sources as the interim MACT 
pool. The remaining sources are temporarily set aside, and the 
sources comprising the interim MACT pool are ranked again from 
lowest to highest emissions. Sources from the interim MACT pool that 
have been flagged due to having feedrates above the upper 99th 
percentile are systematically (from highest to lowest emissions) 
removed from the MACT pool and replaced with sources with the next 
highest ranked SREs if the emissions from the next best source 
initially excluded from the interim MACT pool has lower emissions. 
The sources comprising the revised interim MACT pool now become the 
final MACT pool. Emissions from those sources are again used to 
calculate the MACT floor, with the resulting MACT floor again 
expressed as an emission standard.
---------------------------------------------------------------------------

    Floor levels for existing sources under this feedrate-screened 
variation are presented in Table 8.
    We invite comment on these alternative floor approaches. For more 
information on how the approach would work, see USEPA ``Draft Technical 
Support Document for HWC MACT Replacement Standards, Volume III: 
Selection of MACT Standards,'' March 2004, Chapters 13 and 22.

[[Page 21239]]



                                                             Table 7.--Floor Levels for Existing Sources Under Alternative Option 5
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Mercury                   Semivolatile metals               Low volatile metals                  Total chlorine
                                                           -------------------------------------------------------------------------------------------------------------------------------------
                                                                           Emissions                         Emission                          Emission                           Emission
                      Source category                                --------------------                  concentration                     concentration                      concentration
                                                             SRE \1\                         SRE \1\   --------------------    SRE \1\   --------------------    SRE \1\   ---------------------
                                                                        Stack    Thermal                  Stack    Thermal                  Stack    Thermal                 Stack gas   Thermal
                                                                       gas \2\     \3\                   gas \2\     \3\                   gas \2\     \3\                      \2\        \3\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Incinerators..............................................        27    20,000   n/a \8\        99.89         74   n/a \8\        99.969        33   n/a \8\        99.990         3.1   n/a \8\
                                                                           \9\
                                                           -----------
Cement Kilns..............................................            n/a 4, 5                  99.966        71       140        99.989        11        22               n/a 4, 5
                                                           -----------
Lightweight Aggregate Kilns...............................            n/a 4, 6                  99.78        330       310        99.89        100        95               n/a 4, 6
                                                           -----------
Solid Fuel-Fired Boilers..................................        11  ........   n/a \8\        99.78        180   n/a \8\        97.9         230   n/a \8\               n/a 4, 5
                                                           -----------
Liquid Fuel-Fired Boilers.................................             n/a \4\
                                                                       n/a \4\                  90.4 \7\  27 \7\    45 \7\        99.70         25       55
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ SRE is system removal efficiency expressed as a percent.
\2\ Stack gas concentration is expressed in [mu]g/dscm for all except total chlorine, which is expressed as ppmv.
\3\ Thermal emission is expressed in lb/trillion Btu, except total chlorine which is expressed in lb/billion Btu.
\4\ Unable to determine SRE due to normal feedrate data.
\5\ No SRE due to no reliable back-end control.
\6\ Only one source has back-end control.
\7\ LVM Standards for liquid fuel-fired boilers are for Chromium, only.
\8\ Thermal emissions not appropriate for source categories with sources that do not burn hazardous waste fuels.
\9\ We believe this methodology yields inappropriate MACT mercury floors for incinerators because we have only 11 compliance test conditions, and the best performers spiked
  uncharacteristically high levels of mercury during their compliance test.


                                                Table 8.--Floor Levels for Existing Sources Under Alternative Option 5 With High Feedrate Screen
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Mercury                   Semivolatile metals               Low volatile metals                  Total chlorine
                                                           -------------------------------------------------------------------------------------------------------------------------------------
                                                                           Emissions                         Emission                          Emission                           Emission
                      Source category                                --------------------                  concentration                     concentration                      concentration
                                                             SRE \1\                         SRE \1\   --------------------    SRE \1\   --------------------    SRE \1\   ---------------------
                                                                        Stack    Thermal                  Stack    Thermal                  Stack    Thermal                 Stack gas   Thermal
                                                                       gas \2\     \3\                   gas \2\     \3\                   gas \2\     \3\                      \2\        \3\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Incinerators..............................................        27     7,500   n/a \8\        99.89         64   n/a \8\        99.969        29   n/a \8\        99.990         1.3   n/a \8\
                                                                           \9\
                                                           -----------
Cement Kilns..............................................            n/a 4, 5                  99.966        65       130        99.989        11        18               n/a 4, 5
                                                           -----------
Lightweight Aggregate Kilns...............................            n/a 4, 6                  99.78        330       310        99.89        100        95               n/a 4, 6
                                                           -----------
Solid Fuel-Fired Boilers..................................        11  ........   n/a \8\        99.78        180   n/a \8\        97.9         230   n/a \8\               n/a 4, 5
                                                           -----------
Liquid Fuel-Fired Boilers.................................             n/a \4\
                                                                       n/a \4\                  90.4 \7\  27 \7\   110 \7\        99.70         23       55
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ SRE is system removal efficiency expressed as a percent.
\2\ Stack gas concentration is expressed in [mu]g/dscm for all except total chlorine, which is expressed as ppmv.
\3\ Thermal emission is expressed in lb/trillion Btu, except total chlorine which is expressed in lb/billion Btu.
\4\ Unable to determine SRE due to normal feedrate data.
\5\ No SRE due to no reliable back-end control.
\6\ Only one source has back-end control.
\7\ LVM Standards for liquid fuel-fired boilers are for Chromium, only.
\8\ Thermal emissions not appropriate for source categories with sources that do not burn hazardous waste fuels.
\9\ We believe this methodology yields inappropriate MACT mercury floors for incinerators because we have only 11 compliance test conditions, and the best performers spiked
  uncharacteristically high levels of mercury during the their compliance test.


[[Page 21240]]

VII. How Did EPA Determine the Proposed Emission Standards for 
Hazardous Waste Burning Incinerators?

    The proposed standards for existing and new incinerators that burn 
hazardous waste are summarized in the table below. See proposed Sec.  
63.1219.

          Proposed Standards for Existing and New Incinerators
------------------------------------------------------------------------
                                         Emission standard \1\
 Hazardous air pollutant or  -------------------------------------------
          surrogate             Existing sources         New sources
------------------------------------------------------------------------
Dioxin and furan--sources     0.28 ng TEQ/dscm....  0.11 ng TEQ/dscm.
 equipped with waste heat
 boilers or dry air
 pollution control system
 \2\.
Dioxin and furan--sources     0.2 ng TEQ/dscm; or   0.20 ng TEQ/dscm.
 not equipped with waste       0.40 ng TEQ/dscm
 heat boilers or dry air       and temperature at
 pollution control system      inlet to the
 \2\.                          initial particulate
                               matter control
                               device <=400[deg]F.
Mercury.....................  130 [mu]g/dscm......  8.0 [mu]g/dscm.
Particulate matter..........  34 mg/dscm (0.015 gr/ 1.6 mg/dscm (0.00070
                               dscf).                gr/dscf).
Semivolatile metals.........  59 [mu]g/dscm.......  6.5 [mu]g/dscm.
Low volatile metals.........  84 [mu]g/dscm.......  8.9 [mu]g/dscm.
Hydrogen chloride and         1.5 ppmv or the       0.18 ppmv or the
 chlorine gas \3\.             alternative           alternative
                               emission limits       emission limits
                               under Sec.            under Sec.
                               63.1215.              63.1215.
Hydrocarbons \4,5\..........  10 ppmv (or 100 ppmv  10 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). For sources burning
                               hazardous wastes F020, F021, F022, F023,
                               F026, or F027, however, 99.9999% for each
                               POHC.
------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen dry basis.
\2\ A wet air pollution system followed by a dry air pollution control
  system is not considered to be a dry air pollution control system for
  purposes of this standard. A dry air pollution systems followed a wet
  air pollution control system is considered to be a dry air pollution
  control system for purposes of this standard.
\3\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\4\ Sources that elect to comply with the carbon monoxide standard must
  demonstrate compliance with the hydrocarbon standard during the
  comprehensive performance test.
\5\ Hourly rolling average. Hydrocarbons reported as propane.

A. What Are the Proposed Standards for Dioxin and Furan?

    The proposed standards for dioxin/furan for sources equipped with 
dry air pollution control devices and/or waste heat boilers are 0.28 ng 
TEQ/dscm for existing sources and 0.11 ng TEQ/dscm for new sources. For 
incinerators using either wet air pollution control or no air pollution 
control devices, the proposed standards for dioxin/furan are 0.20 ng 
TEQ/dscm or 0.40 ng TEQ/dscm while limiting the temperature at the 
inlet to the particulate matter control device to less than 400 [deg]F 
for existing sources and 0.20 ng TEQ/dscm for new sources.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Dioxin and furan emissions for existing incinerators are currently 
limited by Sec.  63.1203(a)(1) to 0.20 ng TEQ/dscm; or 0.40 ng TEQ/dscm 
provided that the combustion gas temperature at the inlet to the 
initial particulate matter control device is limited to 400 [deg]F or 
less. (For purposes of compliance, operation of a wet air pollution 
control system is presumed to meet the 400 [deg]F or lower 
requirement.) This standard was promulgated in the Interim Standards 
Rule (See 67 FR at 6796, February 13, 2002).
    Since promulgation of the September 1999 final rule, we have 
obtained additional dioxin/furan emissions data. We now have dioxin/
furan emissions data for over 55 sources. The emissions in our data 
base range from less than 0.001 to 34 ng TEQ/dscm.
    As discussed in Part Two, Section II, we assessed whether 
incinerators equipped with dry air pollution control devices and/or 
waste heat boilers have statistically different emissions than sources 
with either wet air pollution control or no air pollution control 
equipment.\83\ Our statistical analysis indicates dioxin/furan 
emissions between these types of incinerators are significantly 
different. (As we explained there, these differences relate to 
differences in dioxin/furan formation mechanisms, not pollution control 
device efficiency.) Therefore, we believe subcategorization is 
warranted for this emission standard and we are proposing separate 
floor levels.
---------------------------------------------------------------------------

    \83\ A source with a wet air pollution system followed by a dry 
air pollution control system is not considered to be a dry air 
pollution control system for purposes of this standard, while a 
source with a dry air pollution system followed a wet air pollution 
control system is considered to be a dry air pollution control 
system. In addition, we note that a spray dryer is not considered to 
be a wet air pollution control system for purposes of 
subcategorization.
---------------------------------------------------------------------------

    To identify the floor level for incinerators equipped with dry air 
pollution control equipment and/or waste heat boilers, we evaluated the 
compliance test emissions data associated with the most recent test 
campaign using the Emissions Approach described in Part Two, Section 
VI. The calculated floor is 0.28 ng TEQ/dscm, which considers emissions 
variability. This is an emission level that the average of the best 
performing sources could be expected to achieve in 99 of 100 future 
tests when operating under conditions identical to the compliance test 
conditions during which the emissions data were obtained. The 
calculated floor level of 0.28 ng TEQ/dscm is based on five best 
performing sources that achieved this floor level either by the use of 
temperature control at the inlet to dry air pollution control device 
and good combustion or by the use of activated carbon injection. The 
single best performer is equipped with a dry air pollution control 
system and a waste heat boiler, and uses activated carbon injection, 
good combustion, and temperature control to control dioxin/furan 
emissions. The remaining four

[[Page 21241]]

best performers are equipped with dry air pollution systems but do not 
have waste heat recovery boilers. Two of these sources use activated 
carbon, good combustion, and temperature control to control dioxin/
furan emissions.\84\ The other two without waste heat recovery boilers 
use a combination of good combustion and temperature control to control 
emissions.
---------------------------------------------------------------------------

    \84\ One source uses an activated carbon injection system, and 
the other uses a carbon bed.
---------------------------------------------------------------------------

    We then judged the relative stringency of the calculated floor 
level to the interim standard to determine if the proposed floor level 
needed to be ``capped'' by the current interim standard to ensure the 
proposed floor level is not less stringent than an existing federal 
emission standard. A comparison of the calculated floor level of 0.28 
ng TEQ/dscm to the interim standard--0.20 ng TEQ/dscm or 0.40 ng TEQ/
dscm provided that the combustion gas temperature at the inlet to the 
initial particulate matter control device is limited to less than 400 
[deg]F--indicates that a floor level of 0.28 ng TEQ/dscm is more 
stringent than the current interim standard. This judgment is based on 
our belief that the majority of these incinerators are currently 
complying with the 0.40 ng TEQ/dscm and temperature limitation portion 
of the interim standard.\85\ We estimate that this emission level is 
being achieved by 71% of sources and would reduce dioxin/furan 
emissions by 0.28 grams per year.
---------------------------------------------------------------------------

    \85\ We request comment, however, on whether this judgment is 
correct. If an incinerator is operated with a dry air pollution 
control device inlet temperature greater than 400 [deg]F, then it 
may be appropriate to instead require sources to comply with the 
more stringent of the two standards, that is, 0.20 ng TEQ/dscm.
---------------------------------------------------------------------------

    We also considered whether to further subcategorize based on 
whether the incinerator is equipped with a waste heat recovery boiler 
or dry air pollution control device. Our analysis determined that the 
dioxin/furan emissions from incinerators with waste heat recovery 
boilers are not statistically different from those equipped with dry 
air pollution control systems. We propose, therefore, that further 
subcategorization is not necessary given that incinerators using either 
waste heat recovery boilers or dry air pollution control systems can 
readily achieve the calculated floor level using control technologies 
demonstrated by the best performing sources.
    For sources with either wet air pollution control systems or no air 
pollution control equipment, but are not equipped with a heat recovery 
boiler, we contemplated identifying an emission limit but instead rely 
on surrogates for control of organic HAP, namely good combustion 
practices, to be demonstrated by complying with the carbon monoxide or 
hydrocarbon emissions standard and compliance with the destruction and 
removal efficiency standard.\86\ We believe that it would be 
inappropriate to establish a numerical dioxin/furan floor level for 
sources with wet or no air pollution control systems because the floor 
emission level would not be replicable by the best performing sources 
nor duplicable by other sources. Dioxin/furan formation mechanisms are 
complex. Sources with wet or no air pollution control devices may have 
difficulty complying with a numerical dioxin/furan limit that is based 
on the lowest emitting dioxin/furan sources within this subcategory 
because there is not a demonstrated floor control technology that these 
sources can use to ``dial in'' to achieve a given emission level. 
Moreover, dioxin/furan emissions could result from operation under poor 
combustion conditions and formation on particulate matter surfaces in 
duct work, on heat recovery boiler tubes, and on particulates entrained 
in the combustion gas stream. As a result, we would instead identify 
floor control for these sources to be operating under good combustion 
practices by complying with the destruction and removal efficiency and 
carbon monoxide/hydrocarbon standards.
---------------------------------------------------------------------------

    \86\ Use of ``good combustion practices'' does not necessarily 
preclude significant dioxin/furan formation. Our data base suggests, 
however, that incinerators using wet air pollution control systems 
achieve dioxin/furan emissions less than 0.40 ng TEQ/dscm. See 
USEPA, ``Draft Technical Support Document for HWC MACT Replacement 
Standards, Volume III: Selection of MACT Standards,'' March 2004, 
Chapter 2.
---------------------------------------------------------------------------

    Though MACT floor for these units is operating under good 
combustion practices, there is a regulatory limit which is relevant in 
identifying the floor level. Hazardous waste incinerators are complying 
with an interim standard for dioxin/furan--an emission limit of 0.20 ng 
TEQ/dscm or, alternatively, 0.40 ng TEQ/dscm provided that the 
combustion gas temperature at the inlet to the initial particulate 
matter control device is limited to 400 [deg]F or less--that fixes a 
level of performance for the source category. Given that all sources 
are meeting this interim standard and that the interim standard is 
judged as more stringent than a MACT floor of ``good combustion 
practices,'' the dioxin/furan floor level can be no less stringent than 
the current regulatory limit.\87\ Therefore, the proposed floor level 
for incinerators with either wet air pollution control systems or no 
air pollution control equipment that are not equipped with a heat 
recovery boiler is either 0.20 ng TEQ/dscm or 0.40 ng TEQ/dscm provided 
that the combustion gas temperature at the inlet to the initial 
particulate matter control device is limited to 400 [deg]F or less. 
This emission level is currently being achieved by all sources because 
the interim standard is an enforceable standard currently in effect.
---------------------------------------------------------------------------

    \87\ Even though all sources have recently demonstrated 
compliance with the interim standards, the dioxin/furan data in our 
data base preceded the compliance demonstration.
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated beyond-the-floor standards based on the use of control 
technology which removes dioxin/furan, namely use of an activated 
carbon injection system or a carbon bed system as beyond-the-floor 
control for further reduction of dioxin/furan emissions. Activated 
carbon is currently used at three incinerators to control dioxin/furan. 
We evaluated a beyond-the-floor level of 0.10 ng TEQ/dscm for all 
incinerators, which represents a 65-75% reduction in dioxin/furan 
emissions from the floor level. We selected this level because it 
represents a level that is considered routinely achievable with 
activated carbon.\88\
---------------------------------------------------------------------------

    \88\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume V: Emissions Estimates and Engineering 
Costs,'' March 2004, Chapter 4.3.
---------------------------------------------------------------------------

    For incinerators equipped with dry air pollution control equipment 
and/or waste heat boilers, the national incremental annualized 
compliance cost for these sources to meet the beyond-the-floor level 
rather than comply with the floor controls would be approximately $2.2 
million and would provide an incremental reduction in dioxin/furan 
emissions beyond the floor level controls of 0.5 grams TEQ per year. 
Nonair quality health and environmental impacts and energy effects were 
evaluated to estimate the impacts between activated carbon injection 
and carbon beds and controls likely to be used to meet the floor level. 
We estimate that this beyond-the-floor option would increase the amount 
of hazardous waste generated by 1,500 tons per year in addition to 
using an additional 3 million kW-hours per year beyond the requirements 
to achieve the floor level. The costs associated with these hazardous 
waste treatment/disposal and energy impacts are accounted for in the 
national annualized compliance cost estimates. Therefore, based on 
these factors and costs of approximately $4.4 million per

[[Page 21242]]

additional gram of dioxin/furan removed, we are not proposing a beyond-
the-floor standard based on activated carbon injection and carbon bed 
systems.
    For sources with either wet air pollution control systems or no air 
pollution control equipment that are not equipped with a heat recovery 
boiler, the national incremental annualized compliance cost for these 
sources to meet the beyond-the-floor level would be approximately $3.9 
million and would provide an incremental reduction in dioxin/furan 
emissions beyond the MACT floor controls of 0.35 grams TEQ per year. 
Nonair quality health and environmental impacts and energy effects were 
also evaluated. We estimate that this beyond-the-floor option would 
increase the amount of hazardous waste generated by 700 tons per year. 
The option would also require sources to use an additional 2 million 
kW-hours per year and 70 million gallons of water beyond the 
requirements to achieve the floor level. Therefore, based on these 
factors and costs of approximately $11 million per additional gram of 
dioxin/furan removed, we are not proposing a beyond-the-floor standard 
based on activated carbon injection and carbon bed systems.
3. What Is the Rationale for the MACT Floor for New Sources?
    Dioxin and furan emissions for new incinerators are currently 
limited by Sec.  63.1203(b)(1) to 0.20 ng TEQ/dscm. This standard was 
promulgated in the Interim Standards Rule (See 67 FR at 6796, February 
13, 2002).
    For incinerators equipped with dry air pollution control equipment 
and/or waste heat boilers, the calculated floor level is 0.11 ng TEQ/
dscm, which considers variability. This is an emission level that the 
single best performing source identified using the Emissions Approach 
could be expected to achieve in 99 out of 100 future tests when 
operating under conditions identical to the compliance test conditions 
during which the emissions data were obtained.
    For sources with either wet air pollution control systems or no air 
pollution control equipment that are not equipped with a heat recovery 
boiler, as previously discussed for existing sources, we believe that 
it would be inappropriate to establish numerical dioxin/furan emission 
for these sources. We would instead identify floor control for these 
sources to be operating under good combustion practices by complying 
with the destruction and removal efficiency and carbon monoxide/
hydrocarbon standards.
    Though MACT floor for these units is operating under good 
combustion practices, there is a regulatory limit which is relevant in 
identifying the floor level. New hazardous waste incinerators are 
subject to an interim emission standard for dioxin/furan of 0.20 ng 
TEQ/dscm. Given that the interim standard is judged more stringent than 
a MACT floor of ``good combustion practices,'' the dioxin/furan floor 
level can be no less stringent than the current regulatory limit. 
Therefore, the proposed floor level for incinerators with either wet 
air pollution control systems or no air pollution control equipment 
that are not equipped with a heat recovery boiler is 0.20 ng TEQ/dscm. 
Therefore, we are proposing the current interim standard of 0.20 ng 
TEQ/dscm as the floor level for new sources.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated beyond-the-floor standards based on the use of a 
carbon bed system to achieve additional removal of dioxin/furan. Given 
the relatively low dioxin/furan levels at the floor, we made a 
conservative assumption that the use of a carbon bed will provide an 
additional 50% dioxin/furan control. We applied this removal efficiency 
to the dioxin/furan floor levels to identify the beyond-the-floor 
levels.
    For a new incinerator with average gas flowrate equipped with dry 
air pollution control equipment and/or a waste heat boiler, the 
national incremental annualized compliance cost to meet the beyond-the-
floor level of 0.06 ng TEQ/dscm rather than comply with the floor 
controls would be approximately $0.22 million and would provide an 
incremental reduction in dioxin/furan emissions beyond the floor level 
controls of 0.013 grams TEQ per year. Nonair quality health and 
environmental impacts and energy effects were evaluated. Therefore, 
based on these factors and costs of approximately $17 million per 
additional gram of dioxin/furan removed, we are not proposing a beyond-
the-floor standard based on activated carbon bed systems.
    For a source with either a wet air pollution control system or no 
air pollution control equipment that is not equipped with a heat 
recovery boiler, the national incremental annualized compliance cost 
for a new incinerator with an average gas flowrate to meet a beyond-
the-floor level of 0.10 ng TEQ/dscm would be approximately $0.22 
million and would provide an incremental reduction in dioxin/furan 
emissions beyond the MACT floor controls of 0.024 grams TEQ per year. 
Considering the nonair quality health and environmental impacts and 
energy effects in addition to costs of approximately $9.3 million per 
additional gram of dioxin/furan removed, we are not proposing a beyond-
the-floor standard based on a carbon bed system.

B. What Are the Proposed Standards for Mercury?

    We are proposing to establish standards for existing and new 
incinerators that limit emissions of mercury to 130 [mu]g/dscm and 8 
[mu]g/dscm, respectively.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Mercury emissions for existing incinerators are currently limited 
to 130 [mu]g/dscm by Sec.  63.1203(a)(2). This standard was promulgated 
in the Interim Standards Rule (See 67 FR at 6796).
    We have both normal and compliance test emissions data for over 50 
sources. For several sources, we have emissions data from more than one 
test campaign. The mercury stack emissions in our data base range from 
less than 1 to 35,000 [mu]g/dscm, which are expressed as mass of 
mercury per unit volume of stack gas.
    To identify the floor level, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 610 [mu]g/dscm, which 
considers emissions variability. Even though all sources have recently 
demonstrated compliance with the interim standard of 130 [mu]g/dscm, 
all the mercury emissions data in our data base precede initial 
compliance with these interim standards. As a result, the calculated 
floor level of 610 [mu]g/dscm is less stringent than the interim 
standard, which is a regulatory limit relevant in identifying the floor 
level (so as to avoid any backsliding from a current level of 
performance achieved by all incinerators, and hence, the level of 
minimal stringency at which EPA could calculate the MACT floor). 
Therefore, we are proposing the floor level as the current emission 
standard of 130 [mu]g/dscm. This emission level is currently being 
achieved by all sources.
    We invite comment on an alternative approach to identify the floor 
level using available normal emissions data instead of the compliance 
test data. For reasons we discussed above in Part Two, our floor-
setting methodology favors compliance test data over normal emissions 
data. However, there are available more mercury emissions data

[[Page 21243]]

characterized as normal--over 40 test conditions--than the eleven 
compliance test results. Given that the data base includes considerably 
more normal emissions than compliance test data, we invite comment on 
whether the floor analysis should be based on the normal emissions data 
instead of the compliance test data. The floor level considering the 
normal data using the Emissions Approach is 7.8 [mu]g/dscm, which 
considers emissions variability. If we were to adopt such an approach, 
we would require sources to comply with the limit on an annual basis 
because the floor analysis is based on normal emissions data. Under 
this approach, compliance would not be based on the use of a total 
mercury continuous emissions monitoring system because these monitors 
have not been adequately demonstrated as a reliable compliance 
assurance tool at all types of incinerator sources. Instead, a source 
would maintain compliance with the mercury standard by establishing and 
complying with short-term limits on operating parameters for pollution 
control equipment and annual limits on maximum total mercury feedrate 
in all feedstreams.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified two potential beyond-the-floor techniques for control 
of mercury: (1) Activated carbon injection; and (2) control of mercury 
in the hazardous waste feed.
    Use of Activated Carbon Injection. We evaluated activated carbon 
injection as beyond-the-floor control for further reduction of mercury 
emissions. Activated carbon injection is currently being used at three 
incinerators and has been demonstrated for controlling mercury and has 
achieved efficiencies ranging from 80% to greater than 90% depending on 
various factors such as injection rate, mercury speciation in the flue 
gas, flue gas temperature, and carbon type. Given the limited 
experience at hazardous waste combustion systems, we made a 
conservative assumption that the use of activated carbon will provide 
70% mercury control. We evaluated a beyond-the-floor level of 39 [mu]g/
dscm.
    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 $7.1 million and would 
provide an incremental reduction in mercury emissions beyond the MACT 
floor controls of 0.39 tons per year. Nonair quality health and 
environmental impacts and energy effects were evaluated to estimate the 
impacts between activated carbon injection and controls likely to be 
used to meet the floor level. We estimate that this beyond-the-floor 
option would increase the amount of hazardous waste generated by 1,800 
tons per year and would require sources to use an additional 5.8 
million kW-hours per year beyond the requirements to achieve the floor 
level. The costs associated with these hazardous waste treatment/
disposal and energy impacts are accounted for in the national 
annualized compliance cost estimates. Therefore, based on these factors 
and costs of approximately $18 million per additional ton of mercury 
removed, we are not proposing a beyond-the-floor standard based on 
activated carbon injection.
    Feed Control of Mercury in the Hazardous Waste. We also evaluated a 
beyond-the-floor level of 100 [mu]g/dscm, which represents a 20% 
reduction from the floor level. We chose a 20% reduction as a level 
that represents the practicable extent that additional feedrate control 
of mercury in hazardous waste (beyond feedrate control that may be 
necessary to achieve the floor level) can be used and still achieve 
modest emissions reductions.\89\ 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 $1.8 
million and would provide an incremental reduction in mercury emissions 
beyond the MACT floor controls of 0.11 tons per year. Nonair quality 
health and environmental impacts and energy effects were also 
evaluated. Therefore, based on these factors and costs of approximately 
$17 million per additional ton of mercury removed, we are not proposing 
a beyond-the-floor standard based on feed control of mercury in the 
hazardous waste.
---------------------------------------------------------------------------

    \89\ Ideally, a methodology to estimate costs of feed control 
should consider lost revenues associated with hazardous wastes not 
fired and costs to implement feed control of metals and chlorine. We 
attempted to conduct such an analysis; however, we concluded that 
there are too many uncertainties to do this analysis. Instead, we 
developed an alternative approach to cost feed control of metals and 
chlorine in the hazardous waste based on the assumption that a 
source would not implement a feed control strategy if the costs 
exceed the costs to retrofit an existing air pollution control 
device. Thus, our cost estimates of feed control represent an upper 
bound estimate on likely costs to control metals or chlorine in 
hazardous waste. See USEPA, ``Draft Technical Support Document for 
HWC MACT Replacement Standards, Volume V: Emission Estimates and 
Engineering Costs,'' March 2004, Chapter 4.
---------------------------------------------------------------------------

    For the reasons discussed above, we propose a mercury emissions 
standard of 130 [mu]g/dscm for existing incinerators.
3. What Is the Rationale for the MACT Floor for New Sources?
    Mercury emissions from new incinerators are currently limited to 45 
[mu]g/dscm by Sec.  63.1203(b)(2). This standard was promulgated in the 
Interim Standards Rule (See 67 FR at 6796).
    The MACT floor for new sources for mercury would be 8 [mu]g/dscm, 
which considers emissions variability. This is an emission level that 
the single best performing source identified with the SRE/Feed Approach 
considering compliance test data could be expected to achieve in 99 of 
100 future tests when operating under conditions identical to the test 
conditions during which the emissions data were obtained.
    As we did for existing sources, we also invite comment on basing 
the floor analysis on the normal emissions data using the Emissions 
Approach. The floor level using the normal data is 0.70 [mu]g/dscm, 
which considers emissions variability. If we were to adopt such an 
approach, we would require sources to comply with the limit on an 
annual basis because it is based on normal emissions data.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We identified two potential beyond-the-floor techniques for control 
of mercury: (1) Use of a carbon bed; and (2) control of mercury in the 
hazardous waste feed.
    Carbon Bed System. We evaluated a carbon bed system as beyond-the-
floor control for further reduction of mercury emissions. Given the 
relatively low floor level, we made a conservative assumption that the 
use of a carbon bed system would provide 50% mercury control. The 
incremental annualized compliance cost for a new incinerator with 
average gas flow rate to meet a beyond-the-floor level of 4 [mu]g/dscm, 
rather than comply with the floor level, would be approximately $0.22 
million and would provide an incremental reduction in mercury emissions 
of approximately 2.1 pounds per year. Nonair quality health and 
environmental impacts and energy effects are accounted for in the 
national annualized compliance cost estimates. Therefore, based on 
these factors and costs of approximately $200 million per additional 
ton of mercury removed, we are not proposing a beyond-the-floor 
standard based on a carbon bed system.
    Feed Control of Mercury in the Hazardous Waste. We also believe 
that the expense for a reduction in mercury emissions based on further 
control of mercury concentrations in the

[[Page 21244]]

hazardous waste is not warranted. A beyond-the-floor level of 6.4 
[mu]g/dscm, which represents a 20% reduction from the floor level, 
would result in a small incremental reduction in mercury emissions. For 
similar reasons discussed above for existing sources, we likewise 
conclude that a beyond-the-floor standard based on controlling the 
mercury in the hazardous waste feed would not be justified because of 
the costs and emission reductions. Therefore, we propose a mercury 
standard of 8 [mu]g/dscm for new sources.

C. What Are the Proposed Standards for Particulate Matter?

    We are proposing to establish standards for existing and new 
incinerators that limit emissions of particulate matter to 0.015 and 
0.00070 gr/dscf, respectively.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Particulate matter emissions for existing incinerators are 
currently limited to 0.015 gr/dscf (34 mg/dscm) by Sec.  63.1203(a)(7). 
This standard was promulgated in the Interim Standards Rule (See 67 FR 
at 6796). The particulate matter standard is a surrogate control for 
the hazardous air pollutant metals antimony, cobalt, manganese, nickel, 
and selenium.
    We have compliance test emissions data for most incinerators. For 
some sources, we have compliance test emissions data from more than one 
compliance test campaign. Our data base of particulate matter stack 
emission concentrations range from 0.0002 to 0.078 gr/dscf.
    To identify the MACT floor for incinerators, we evaluated the 
compliance test emissions data associated with the most recent test 
campaign using the Air Pollution Control Technology Approach. The 
calculated floor is 0.020 gr/dscf (46 mg/dscm), which considers 
emissions variability. This is an emission level that the average of 
the best performing sources could be expected to achieve in 99 of 100 
future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. The calculated floor level of 0.020 gr/dscf is less stringent 
than the interim standard of 0.015 gr/dscf, which is a regulatory limit 
relevant in identifying the floor level (so as to avoid any backsliding 
from a current level of performance achieved by all incinerators, and 
hence, the level of minimal stringency at which EPA could calculate the 
MACT floor). Therefore, we are proposing the floor level as the current 
emission standard of 0.015 gr/dscf. This emission level is currently 
being achieved by all sources.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated improved particulate matter control to achieve a 
beyond-the-floor standard of 17 mg/dscm (0.0075 gr/dscf). For an 
existing incinerator that needs a significant reduction in particulate 
matter emissions, we assumed and costed a new baghouse to achieve the 
beyond-the-floor level. If little or modest emissions reductions were 
needed, then improved control was costed as design, operation, and 
maintenance modifications of the existing particulate matter control 
equipment.
    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 $3.9 million and would 
provide an incremental reduction in particulate matter emissions beyond 
the MACT floor of 48 tons per year. Nonair quality health and 
environmental impacts and energy effects were evaluated to estimate the 
nonair quality health and environmental impacts between further 
improvements to control particulate matter and controls likely to be 
used to meet the floor level. We estimate that this beyond-the-floor 
option would increase the amount of hazardous waste generated by 48 
tons per year and would also require sources to use an additional 2.7 
million kW-hours per year beyond the requirements to achieve the floor 
level. The costs associated with these impacts are accounted for in the 
national annualized compliance cost estimates. Therefore, based on 
these factors and costs of approximately $81,000 per additional ton of 
particulate matter removed, we are not proposing a beyond-the-floor 
standard based on improved particulate matter control.
3. What Is the Rationale for the MACT Floor for New Sources?
    Particulate matter emissions from new incinerators are currently 
limited to 0.015 gr/dscf (34 mg/dscm) by Sec.  63.1203(b)(7). This 
standard was promulgated in the Interim Standards Rule (See 67 FR at 
6796).
    The MACT floor for new sources for particulate matter would be 1.6 
mg/dscm (0.00070 gr/dscf), which considers emissions variability. This 
is an emission level that the single best performing source identified 
with the Air Pollution Control Technology Approach could be expected to 
achieve in 99 of 100 future tests when operating under operating 
conditions identical to the test conditions during which the emissions 
data were obtained.
    As discussed in Part Two, Section II, we considered whether to 
propose separate standards (subcategorize) for particulate matter for 
several different potential subcategories such as government-owned 
versus non-government incinerators and liquid injection versus solid 
fuel-fired incinerators. We determined that the emission 
characteristics from these potential subcategories are not 
statistically different, and, therefore, separate standards for 
particulate matter are not warranted. We request comment on whether 
these subcategorization considerations capture the appropriate 
differences in manufacturing process, emission characteristics, or 
technical feasibility for particulate matter. We note, for example, the 
single best performing source, which is the basis of the floor level 
for new incinerators, is an incinerator used to decontaminate scrap 
metal. Though we believe these sources are best performers because they 
use highly efficient baghouses for the capture of particulate matter, 
and, therefore, appropriate for inclusion in the analysis, we invite 
comment on whether we have considered the appropriate subcategories for 
particulate matter. We note that a floor level based on the second best 
performing incinerator source would be 0.0021 gr/dscf.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated improved emissions control based on a state-of-the-art 
baghouse using a high quality fabric filter bag material to achieve a 
beyond-the-floor standard of 1.2 mg/dscm (0.0005 gr/dscf). The 
incremental annualized compliance cost for a new incinerator to meet 
this beyond-the-floor level, rather than comply with the floor level, 
would be approximately $80,000 and would provide an incremental 
reduction in particulate matter emissions of approximately 0.15 tons 
per year. Nonair quality health and environmental impacts and energy 
effects were also evaluated and are accounted for in the national 
annualized compliance cost estimates. We estimate that this option 
would require a new source to use an additional 0.2 million kW-hours 
per year. For these reasons and a cost-effectiveness of $0.53 million 
per ton of particulate matter removed, we are not proposing a beyond-
the-floor standard based on improved particulate matter control for new 
incinerators. Therefore, we propose a particulate

[[Page 21245]]

matter standard of 1.6 mg/dscm for new sources.

D. What Are the Proposed Standards for Semivolatile Metals?

    We are proposing to establish standards for existing and new 
incinerators that limit emissions of semivolatile metals (cadmium and 
lead) to 59 ug/dscm and 6.5 ug/dscm, respectively.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Semivolatile metals emissions from existing incinerators are 
currently limited to 240 ug/dscm by Sec.  63.1203(a)(3). This standard 
was promulgated in the Interim Standards Rule (See 67 FR at 6796). 
Incinerators control emissions of semivolatile metals with air 
pollution control equipment and/or by controlling the feed 
concentration of semivolatile metals in the hazardous waste.
    We have compliance test emissions data for nearly 30 incinerators. 
Semivolatile metal stack emissions range from approximately 4 to 29,000 
ug/dscm. These emissions are expressed as mass of semivolatile metals 
per unit volume of stack gas. Lead was usually the most significant 
contributor to semivolatile emissions during compliance test 
conditions.
    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 59 ug/dscm, which considers 
emissions variability. This is an emission level that the average of 
the best performing sources could be expected to achieve in 99 of 100 
future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 52% 
of sources. The floor level would reduce semivolatile metals emissions 
by 0.43 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified two potential beyond-the-floor techniques for control 
of semivolatile metals: (1) Improved particulate matter control; and 
(2) control of semivolatile metals in the hazardous waste feed.
    Improved Particulate Matter Control. Controlling particulate matter 
also controls emissions of semivolatile metals. We evaluated a beyond-
the-floor level of 30 [mu]g/dscm, which is a 50% reduction from the 
floor level, based on additional reductions of particulate matter 
emissions by operating and maintaining existing control equipment to 
have improved collection efficiency. 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 $3.0 million and would provide an incremental reduction 
in semivolatile metals emissions beyond the MACT floor controls of 190 
pounds per year. Nonair quality health and environmental impacts and 
energy effects were evaluated to estimate the impacts between further 
improvements to control particulate matter and controls likely to be 
used to meet the floor level. We estimate that this beyond-the-floor 
option would increase the amount of hazardous waste generated by 50 
tons per year and would require sources to use an additional 3.4 
million kW-hours per year beyond the requirements to achieve the floor 
level. The costs associated with these hazardous waste treatment and 
energy impacts are accounted for in the national annualized compliance 
cost estimates. Therefore, based on these factors and costs of 
approximately $31 million per additional ton of semivolatile metals 
removed, we are not proposing a beyond-the-floor standard based on 
improved particulate matter control.
    Feed Control of Semivolatile Metals in the Hazardous Waste. We also 
evaluated a beyond-the-floor level of 47 [mu]g/dscm, which represents a 
20% reduction from the floor level. We chose a 20% reduction as a level 
that represents the practicable extent that additional feedrate control 
of semivolatile metals in the hazardous waste can be used and still 
achieve modest emissions reductions. 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 $1.7 million and would provide an incremental reduction 
in semivolatile metals emissions beyond the MACT floor of 90 pounds per 
year. Nonair quality health and environmental impacts and energy 
effects were also evaluated and are accounted for in the national 
annualized compliance cost estimates. For these reasons and costs of 
approximately $39 million per additional ton of semivolatile metals 
removed, we are not proposing a beyond-the-floor standard based on feed 
control of semivolatile metals in the hazardous waste.
    For the reasons discussed above, we propose to establish the 
emission standard for existing incinerators at 59 [mu]g/dscm.
3. What Is the Rationale for the MACT Floor for New Sources?
    Semivolatile metals emissions from new incinerators are currently 
limited to 120 [mu]g/dscm by Sec.  63.1203(b)(3). This standard was 
promulgated in the Interim Standards Rule (See 67 FR at 6796).
    The MACT floor for new sources for semivolatile metals would be 6.5 
[mu]g/dscm, which considers emissions variability. This is an emission 
level that the single best performing source identified with the SRE/
Feed Approach could be expected to achieve in 99 of 100 future tests 
when operating under conditions identical to the test conditions during 
which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We identified two potential beyond-the-floor techniques for control 
of semivolatile metals: (1) Improved control of particulate matter; and 
(2) control of semivolatile metals in the hazardous waste feed.
    Improved Particulate Matter Control. We evaluated a standard of 3.3 
[mu]g/dscm, which is a 50% reduction from the floor level, based on a 
state-of-the-art baghouse using a high quality fabric filter bag 
material as beyond-the-floor control for further reductions in 
semivolatile metals emissions. The incremental annualized compliance 
cost for a new incinerator with an average gas flow rate to meet this 
beyond-the-floor level, rather than comply with the floor level, would 
be approximately $80,000 and would provide an incremental reduction in 
semivolatile metals emissions of approximately 2 pounds per year. 
Nonair quality health and environmental impacts and energy effects were 
also evaluated and are included in the cost estimates. We estimate that 
this option would require a new source to use an additional 0.2 million 
kW-hours per year. For these reasons and costs of $94 million per ton 
of semivolatile metals removed, we are not proposing a beyond-the-floor 
standard based on improved particulate matter control for new sources.
    Feed Control of Semivolatile Metals in the Hazardous Waste. We also 
believe that the expense for a reduction in semivolatile metals 
emissions based on further control of semivolatile metals 
concentrations in the hazardous waste is not warranted. A beyond-the-
floor level of 5.2 [mu]g/dscm, which represents a 20% reduction from 
the floor level, would result in little additional semivolatile metals 
reductions. For similar reasons discussed above for existing sources, 
we

[[Page 21246]]

judge that a beyond-the-floor standard based on controlling the 
semivolatile metals in the hazardous waste feed would not be justified 
because of the costs and expected emission reductions. Therefore, we 
propose a semivolatile metals standard of 6.5 [mu]g/dscm for new 
sources.

E. What Are the Proposed Standards for Low Volatile Metals?

    We are proposing to establish standards for existing and new 
incinerators that limit emissions of low volatile metals (arsenic, 
beryllium, and chromium) to 84 [mu]g/dscm and 8.9 [mu]g/dscm, 
respectively.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Low volatile metals emissions from existing incinerators are 
currently limited to 97 [mu]g/dscm by Sec.  63.1203(a)(4). This 
standard was promulgated in the Interim Standards Rule (See 67 FR at 
6796). Incinerators control emissions of low volatile metals with air 
pollution control equipment and/or by controlling the feed 
concentration of low volatile metals in the hazardous waste.
    We have compliance test emissions data for nearly 30 incinerators. 
Low volatile metal stack emissions range from approximately 1 to 4,300 
[mu]g/dscm. These emissions are expressed as mass of low volatile 
metals per unit volume of stack gas.
    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 84 [mu]g/dscm, which 
considers emissions variability. This is an emission level that the 
average of the best performing sources could be expected to achieve in 
99 of 100 future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 85% 
of sources and would reduce low volatile metals emissions by 56 pounds 
per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified two potential beyond-the-floor techniques for control 
of low volatile metals: (1) Improved particulate matter control; and 
(2) control of low volatile metals in the hazardous waste feed.
    Improved Particulate Matter Control. Controlling particulate matter 
also controls emissions of low volatile metals. We evaluated a beyond-
the-floor level of 42 [mu]g/dscm, which is a 50% reduction from the 
floor level, based on additional reductions of particulate matter 
emissions by operating and maintaining existing control equipment to 
have improved collection efficiency. 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 $0.88 million and would provide an incremental reduction 
in low volatile metals emissions beyond the MACT floor controls of 365 
pounds per year. Nonair quality health and environmental impacts and 
energy effects were evaluated to estimate the impacts between further 
improvements to control particulate matter and controls likely to be 
used to meet the floor level. We estimate that this beyond-the-floor 
option would increase the amount of hazardous waste generated by 100 
tons per year and would require sources to use an additional 0.7 
million kW-hours per year beyond the requirements to achieve the floor 
level. The costs associated with these impacts are accounted for in the 
national annualized compliance cost estimates. Therefore, based on 
these factors and costs of approximately $4.8 million per additional 
ton of low volatile metals removed, we are not proposing a beyond-the-
floor standard based on improved particulate matter control.
    Feed Control of Low Volatile Metals in the Hazardous Waste. We also 
evaluated a beyond-the-floor level of 67 [mu]g/dscm, which represents a 
20% reduction from the floor level. We chose a 20% reduction as a level 
that represents the practicable extent that additional feedrate control 
of low volatile metals in the hazardous waste can be used and still 
achieve modest emissions reductions. 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 $0.25 million and would provide an incremental reduction 
in low volatile metals emissions beyond the MACT floor controls of 0.11 
tons per year. Nonair quality health and environmental impacts and 
energy effects were also evaluated and are accounted for in the 
national annualized compliance cost estimates. Therefore, based on 
these factors and costs of approximately $2.2 million per additional 
ton of low volatile metals removed, we are not proposing a beyond-the-
floor standard based on feed control of low volatile metals in the 
hazardous waste.
    For the reasons discussed above, we propose to establish the 
emission standard for existing incinerators at 84 [mu]g/dscm.
3. What Is the Rationale for the MACT Floor for New Sources?
    Low volatile metal emissions from new incinerators are currently 
limited to 97 [mu]g/dscm by Sec.  63.1203(b)(4). This standard was 
promulgated in the Interim Standards Rule (See 67 FR at 6796).
    The MACT floor for new sources for low volatile metals would be 8.9 
[mu]g/dscm, which considers emissions variability. This is an emission 
level that the single best performing source identified with the SRE/
Feed Approach could be expected to achieve in 99 of 100 future tests 
when operating under conditions identical to the test conditions during 
which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We identified two potential beyond-the-floor techniques for control 
of low volatile metals: (1) Improved control of particulate matter; and 
(2) control of low volatile metals in the hazardous waste feed.
    Improved Particulate Matter Control. We evaluated a standard of 4.5 
[mu]g/dscm, which is a 50% reduction from the floor level, based on a 
state-of-the-art baghouse using a high quality fabric filter bag 
material as beyond-the-floor control for further reductions in low 
volatile metals emissions. The incremental annualized compliance cost 
for a new incinerator with average gas flowrate to meet this beyond-
the-floor level, rather than comply with the floor level, would be 
approximately $80,000 and would provide an incremental reduction in low 
volatile metals emissions of approximately 2.3 pounds per year. Nonair 
quality health and environmental impacts and energy effects were also 
evaluated and are included in the cost estimates. For these reasons and 
costs of $69 million per ton of low volatile metals removed, we are not 
proposing a beyond-the-floor standard based on improved particulate 
matter control for new sources.
    Feed Control of Low Volatile Metals in the Hazardous Waste. We also 
believe that the expense associated with a reduction in low volatile 
metals emissions based on further control of low volatile metals 
concentrations in the hazardous waste is not warranted. A beyond-the-
floor level of 7.1 [mu]g/dscm, which represents a 20% reduction from 
the floor level, would result in little additional low volatile metals 
reductions. For similar reasons discussed above for existing sources, 
we

[[Page 21247]]

judge that a beyond-the-floor standard based on controlling the low 
volatile metals in the hazardous waste feed would not be cost-effective 
or otherwise appropriate. Therefore, we propose a low volatile metals 
standard of 8.9 [mu]g/dscm for new sources.

F. What Are the Proposed Standards for Hydrogen Chloride and Chlorine 
Gas?

    We are proposing to establish standards for existing and new 
incinerators that limit total chlorine emissions (hydrogen chloride and 
chlorine gas, combined, reported as a chloride equivalent) to 1.5 and 
0.18 ppmv, respectively. However, we are also proposing to establish 
alternative risk-based standards, pursuant to CAA section 112(d)(4), 
which a source could elect to comply with by in lieu of the MACT 
emission standards for total chlorine. The emission limits would be 
based on national exposure standards that ensure protection of public 
health with an ample margin of safety. See Part Two, Section XIII for 
additional details.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Total chlorine emissions from existing incinerators are limited to 
77 ppmv by Sec.  63.1203(a)(6). This standard was promulgated in the 
Interim Standards Rule (See 67 FR at 6796). Incinerators control 
emissions of total chlorine with air pollution control equipment and/or 
by controlling the feed concentration of chlorine in the hazardous 
waste.
    We have compliance test emissions data for most incinerators. Total 
chlorine emissions range from less than 1 ppmv to 460 ppmv.
    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 1.5 ppmv, which considers 
emissions variability. This is an emission level that the best 
performing feed control sources could be expected to achieve in 99 of 
100 future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 11% 
of sources and reductions to the floor level would reduce total 
chlorine emissions by 286 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified two potential beyond-the-floor techniques for control 
of total chlorine: (1) Improved control with wet scrubbing; and (2) 
control of chlorine in the hazardous waste feed.
    Use of Wet Scrubbing. We evaluated a beyond-the-floor level of 0.8 
ppmv based on improved wet scrubbers that would include increasing the 
liquid to gas ratio, increasing the liquor pH, and replacing the 
existing packing material with new more efficient packing material. We 
made a conservative assumption that an improved wet scrubber will 
provide 50% total chlorine control beyond the controls needed to 
achieve the floor level given the low total chlorine levels at the 
floor. Applying this wet scrubbing removal efficiency to the total 
chlorine floor level of 1.5 ppmv leads to a beyond-the-floor level 0.8 
ppmv. 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 $1.7 million and would 
provide an incremental reduction in total chlorine emissions beyond the 
MACT floor controls of 6 tons per year. We also evaluated nonair 
quality health and environmental impacts and energy effects between 
improved wet scrubbers and controls likely to be used to meet the floor 
level. We estimate that this beyond-the-floor option would increase the 
amount of waste water generated by 270 million gallons per year. The 
option would also require sources to use an additional 3.2 million kW-
hours per year and 270 million gallons of water beyond the requirements 
to achieve the floor level. The costs associated with these impacts are 
accounted for in the national annualized compliance cost estimates. 
Therefore, based on these factors and costs of approximately $0.29 
million per additional ton of total chlorine removed, we are not 
proposing a beyond-the-floor standard based on improved wet scrubbing.
    Feed Control of Chlorine in the Hazardous Waste. We also evaluated 
a beyond-the-floor level of 1.2 ppmv, which represents a 20% reduction 
from the floor level. We chose a 20% reduction as a level that 
represents the practicable extent that additional feedrate control of 
chlorine in hazardous waste can be used and still achieve appreciable 
emissions reductions. 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 $0.69 million and 
would provide an incremental reduction in total chlorine emissions 
beyond the MACT floor controls of 2.5 tons per year. Nonair quality 
health and environmental impacts and energy effects were also evaluated 
and are accounted for in the national annualized compliance cost 
estimates. Therefore, based on these factors and costs of approximately 
$0.28 million per additional ton of total chlorine removed, we are not 
proposing a beyond-the-floor standard based on feed control of chlorine 
in the hazardous waste.
    For the reasons discussed above, we propose to establish the 
emission standard for existing incinerators at 1.5 ppmv.
3. What Is the Rationale for the MACT Floor for New Sources?
    Total chlorine emissions from incinerators are currently limited to 
21 ppmv by Sec.  63.1203(b)(6). This standard was promulgated in the 
Interim Standards Rule (See 67 FR at 6796). The MACT floor for new 
sources for total chlorine would be 0.18 ppmv, which considers 
emissions variability. This is an emission level that the single best 
performing source identified with the SRE/Feed Approach could be 
expected to achieve in 99 of 100 future tests when operating under 
conditions identical to the test conditions during which the emissions 
data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We identified similar potential beyond-the-floor techniques for 
control of total chlorine for new sources: (1) Use of improved wet 
scrubbers; and (2) control of chlorine in the hazardous waste feed.
    Use of Wet Scrubbing. We evaluated a beyond-the-floor level of 0.1 
ppmv using wet scrubbers as beyond-the-floor control for further 
reductions in total chlorine emissions. We made a conservative 
assumption that an improved wet scrubber will provide 50% total 
chlorine reductions beyond the controls needed to achieve the floor 
level given the low total chlorine levels at the floor. The incremental 
annualized compliance cost for a new incinerator with an average gas 
flowrate to meet this beyond-the-floor level, rather than comply with 
the floor level, would be approximately $0.2 million and would provide 
an incremental reduction in total chlorine emissions of approximately 
35 pounds per year. Nonair quality health and environmental impacts and 
energy effects were also evaluated and are included in the cost 
estimates. We estimate that this option would increase the amount of 
wastewater generated by 50 million gallons per year and would require a 
new source to use an additional 0.5 million kW-hours per year beyond 
the requirements to achieve the floor level. For these reasons and

[[Page 21248]]

costs of $12 million per ton of chlorine removed, we are not proposing 
a beyond-the-floor standard based on improved wet scrubbing control for 
new sources.
    Feed Control of Chlorine in the Hazardous Waste. We also believe 
that the expense associated with a reduction in chlorine emissions 
based on further control of chlorine concentrations in the hazardous 
waste is not warranted. We considered a beyond-the-floor level of 0.14 
ppmv, which represents a 20% reduction from the floor level. For 
similar reasons discussed above for existing sources, we judge that a 
beyond-the-floor standard based on controlling the chlorine in the 
hazardous waste feed would not be cost-effective or otherwise 
appropriate. Therefore, we propose a chlorine standard of 0.18 ppmv for 
new sources.

G. What Are the Standards for Hydrocarbons and Carbon Monoxide?

    Hydrocarbon and carbon monoxide standards are surrogates to control 
emissions of organic hazardous air pollutants for existing and new 
incinerators. The standards limit hydrocarbons and carbon monoxide 
concentrations to 10 ppmv or 100 ppmv. See Sec. Sec.  63.1203(a)(5) and 
(b)(5). Existing and new incinerators can elect to comply with either 
the hydrocarbon limit or the carbon monoxide limit on a continuous 
basis. Sources that 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. 
The rationale for these decisions are discussed in the September 1999 
final rule (64 FR at 52900). We view the standards for hydrocarbons and 
carbon monoxide as unaffected by the Court's vacature of the challenged 
regulations in its decision of July 24, 2001. We therefore are not 
proposing these standards for incinerators, but rather are mentioning 
them here for the reader's convenience.

H. What Are the Standards for Destruction and Removal Efficiency?

    The destruction and removal efficiency (DRE) standard is a 
surrogate to control emissions of organic hazardous air pollutants 
other than dioxin/furans. The standard for existing and new 
incinerators requires 99.99% DRE for each principal organic hazardous 
constituent, except that 99.9999% DRE is required if specified dioxin-
listed hazardous wastes are burned. See Sec. Sec.  63.1203(c). The 
rationale for these decisions are discussed in the September 1999 final 
rule (64 FR at 52902). We view the standards for DRE as unaffected by 
the Court's vacature of the challenged regulations in its decision of 
July 24, 2001. We therefore are not proposing these standards for 
incinerators, but rather are mentioning them here for the reader's 
convenience.

VIII. How Did EPA Determine the Proposed Emission Standards for 
Hazardous Waste Burning Cement Kilns?

    In this section, the basis for the proposed emission standards is 
discussed. See proposed Sec.  63.1220 The proposed 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.\90\ The 
proposed standards for existing and new cement kilns that burn 
hazardous waste are summarized in the table below:
---------------------------------------------------------------------------

    \90\ Currently, we are not aware of any preheater/preacalciner 
kiln that vents its alkali bypass gases through a separate stack.

          Proposed Standards for Existing and New Cement Kilns
------------------------------------------------------------------------
                                         Emission standard \1\
 Hazardous air pollutant or  -------------------------------------------
          surrogate             Existing sources         New sources
------------------------------------------------------------------------
Dioxin and furan \1\........  0.20 ng TEQ/dscm; or 0.40 ng TEQ/dscm and
                               control of flue gas temperature not to
                               exceed 400[deg]F at the inlet to the
                               particulate matter control device.
=============================
Particulate Matter..........  65 mg/dscm (0.028 gr/ 13 mg/dscm (0.0058
                               dscf).                gr/dscf).
Semivolatile metals \3\.....  4.0 x 10-4 lb/MMBtu.  6.2 x 10-5 lb/MMBtu.
Low volatile metals \3\.....  1.4 x 10-5 lb/MMBtu.  1.4 x 10-5 lb/MMBtu.
Hydrogen chloride and         110 ppmv or the       78 ppmv or the
 chlorine gas \4\.             alternative           alternative
                               emission limits       emission limits
                               under Sec.            under Sec.
                               63.1215.              63.1215.
Hydrocarbons: kilns without   20 ppmv (or 100 ppmv  Greenfield kilns: 20
 bypass \5,\ \6\.              carbon monoxide)      ppmv (or 100 ppmv
                               \5\.                  carbon monoxide and
                                                     50 ppmv \7\
                                                     hydrocarbons). All
                                                     others: 20 ppmv (or
                                                     100 ppmv carbon
                                                     monoxide) \5\.
Hydrocarbons: kilns with      No main stack         50 ppmv \7\.
 bypass; main stack \6,\ \8\.  standard.
Hydrocarbons: kilns with      10 ppmv (or 100 ppmv  10 ppmv (or 100 ppmv
 bypass; bypass duct and       carbon monoxide).     carbon monoxide).
 stack \5,\ \6,\ \8\.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen, dry basis. If
  there is a separate alkali bypass stack, then both the alkali bypass
  and main stack emissions must be less than the emission standard.
\2\ Mercury standard is an annual limit.
\3\ Standards are expressed as mass of pollutant stack emissions
  attributable to the hazardous waste per million British thermal unit
  heat input of the hazardous waste.
\4\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\5\ Sources that elect to comply with the carbon monoxide standard must
  demonstrate compliance with the hydrocarbon standard during the
  comprehensive performance test.
\6\ Hourly rolling average. Hydrocarbons reported as propane.

[[Page 21249]]

 
\7\ Applicable only to newly-constructed cement kilns at greenfield
  sites (see 64 FR at 52885). The 50 ppmv standard is a 30-day block
  average limit.
\8\ Measurement made in the bypass sampling system of any kiln (e.g.,
  alkali bypass of a preheater/precalciner kiln; midkiln gas sampling
  system of a long kiln).

A. What Are the Proposed Standards for Dioxin and Furan?

    We are proposing to establish standards for existing and new cement 
kilns that limit emissions of dioxin and furans to either 0.20 ng TEQ/
dscm or 0.40 ng TEQ/dscm and control of flue gas temperature not to 
exceed 400[deg]F at the inlet to the particulate matter control device.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Dioxin and furan emissions for existing cement kilns are currently 
limited by Sec.  63.1204(a)(1) to 0.20 ng TEQ/dscm or 0.40 ng TEQ/dscm 
and control of flue gas temperature not to exceed 400[deg]F at the 
inlet to the particulate matter control device. This standard was 
promulgated in the Interim Standards Rule (See 67 FR at 6796, February 
13, 2002).
    Since promulgation of the 1999 final rule, we have obtained 
additional dioxin/furan emissions data. We now have compliance test 
emissions data for all but one cement kiln that burns hazardous waste. 
The compliance test dioxin/furan emissions in our data base range from 
approximately 0.004 to 20 ng TEQ/dscm.\91\ Cement kilns control dioxin 
by quenching kiln gas temperatures so that gas temperatures at the 
inlet to the particulate matter control device are below the range of 
optimum dioxin/furan formation.
---------------------------------------------------------------------------

    \91\ Even though all sources have recently demonstrated 
compliance with the interim standards, the dioxin/furan data in our 
data base preceded the compliance demonstration. This explains why 
we have emissions data that are higher than the interim standard.
---------------------------------------------------------------------------

    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
Emissions Approach described in Part Two, Section VI.C above. The 
calculated floor is 0.22 ng TEQ/dscm, which considers emissions 
variability. These best performing sources controlled inlet 
temperatures to the particulate matter control device from 380[deg]-
475[deg]F. Although some best performing sources had inlet temperatures 
to the particulate matter control device within the optimum temperature 
range (i.e., 400[deg]F) for formation of dioxin/furan, their 
emissions were lower than other non-best performing sources. Our data 
base shows that these other non-best performing sources, when operating 
within a temperature range up to 475[deg]F, had emissions of dioxin/
furan as high as 1.2 ng TEQ/dscm. We cannot explain why some sources 
emit dioxin/furan at significantly lower levels than other sources 
operating at similar control device inlet temperatures. As noted 
earlier, there are many uncertainties and imperfectly understood 
complexities relating to dioxin/furan formation.
    The data generally support the relationship between inlet 
temperature to the particulate matter control device and dioxin/furan 
emissions: When inlet temperatures are below the optimum range of 
formation, dioxin/furan emissions are lower. However, the converse may 
not hold: When inlet temperatures are within the optimum range of 
formation, dioxin/furan emissions may or may not be higher (but in most 
cases are higher). Moreover, we are concerned that a floor level of 
0.22 ng TEQ/dscm is not replicable by all sources using temperature 
control because we have emissions data from sources operating below the 
optimum temperature range of dioxin/furan formation that is higher than 
the calculated floor level of 0.22 ng TEQ/dscm. As a result of this 
concern, we would identify the floor level as 0.22 ng TEQ/dscm or 
controlling the inlet temperature to the particulate matter control 
device.
    Allowing a source to comply with a temperature limit alone, 
however, absent a numerical dioxin/furan emission limit, is less 
stringent than the current interim standard of 0.20 ng TEQ/dscm, or 
0.40 ng TEQ/dscm and control of flue gas temperature not to exceed 
400[deg]F at the inlet to the particulate matter control device. The 
current interim standard is a regulatory limit that is relevant in 
identifying the floor level because it fixes a level of performance for 
the source category. Given that all sources are achieving this interim 
standard and that the interim standard is judged as more stringent than 
the calculated MACT floor, the dioxin/furan floor level can be no less 
stringent than the current regulatory limit. We are, therefore, 
proposing the dioxin/furan floor level as 0.20 ng TEQ/dscm or 0.40 ng 
TEQ/dscm and control of flue gas temperature not to exceed 400[deg]F at 
the inlet to the particulate matter control device. This emission level 
is being achieved by all sources because it is the current required 
interim standard.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated activated carbon injection as beyond-the-floor control 
for further reduction of dioxin/furan emissions. Activated carbon has 
been demonstrated for controlling dioxin/furans in various combustion 
applications. However, currently no cement kiln that burns hazardous 
waste uses activated carbon injection. We evaluated a beyond-the-floor 
level of 0.10 ng TEQ/dscm, which represents a 75% reduction in dioxin/
furan emissions from the floor level. We selected this level because it 
represents a level that is considered routinely achievable with 
activated carbon injection. In addition, we assumed for costing 
purposes that cement kilns needing activated carbon injection to 
achieve the beyond-the-floor level would install the activated carbon 
injection system after the existing particulate matter control device 
and add a new, smaller baghouse to remove the injected carbon with the 
adsorbed dioxin/furan. We chose this costing approach to address 
potential concerns that injected carbon may interfere with cement kiln 
dust recycling practices.
    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 $21 million and would provide an 
incremental reduction in dioxin/furan emissions beyond the MACT floor 
controls of 3.4 grams TEQ per year. Nonair quality health and 
environmental impacts and energy effects were evaluated to estimate the 
impacts between activated carbon injection and controls likely to be 
used to meet the floor level. We estimate that this beyond-the-floor 
option would increase the amount of solid waste \92\ generated by 7,800 
tons per year and would require sources to use an additional 2.6 
million kW-hours per year beyond the requirements to achieve the floor 
level. The costs associated with these impacts are accounted for in the 
national annualized compliance cost estimates. Therefore, based on 
these factors and costs of approximately $6.2 million per additional 
gram of dioxin/furan removed, we are not proposing a

[[Page 21250]]

beyond-the-floor standard based on use of activated carbon injection.
---------------------------------------------------------------------------

    \92\ Under the exemption from hazardous waste status in Sec.  
261.4(b)(8), cement kiln dust is not currently classified as a 
hazardous waste.
---------------------------------------------------------------------------

3. What Is the Rationale for the MACT Floor for New Sources?
    Dioxin and furan emissions for new cement kilns are currently 
limited by Sec.  63.1204(b)(1) to either 0.20 ng TEQ/dscm or 0.40 ng 
TEQ/dscm and control of flue gas temperature not to exceed 400[deg]F at 
the inlet to the particulate matter control device. This standard was 
promulgated in the Interim Standards Rule (See 67 FR at 6796).
    The calculated MACT floor for new sources would be 0.21 ng TEQ/
dscm, which considers emissions variability. This is an emission level 
that the single best performing source identified by the Emissions 
Approach could be expected to achieve in 99 of 100 future tests when 
operating under conditions identical to the test conditions during 
which the emissions data were obtained. As discussed for existing 
sources, we are concerned that a floor level of 0.21 ng TEQ/dscm would 
not be reproducible by all sources using temperature control because we 
have emissions data from sources operating below the optimum 
temperature range of dioxin/furan formation that is higher than the 
calculated floor level of 0.21 ng TEQ/dscm. As a result of this 
concern, we would identify the MACT floor as 0.21 ng TEQ/dscm or 
controlling the inlet temperature to the particulate matter control 
device.
    Allowing a source to comply with a temperature limit alone, 
however, absent a numerical dioxin/furan emission limit, is less 
stringent than the current interim standard of 0.20 ng TEQ/dscm, or 
0.40 ng TEQ/dscm and control of flue gas temperature not to exceed 
400[deg]F at the inlet to the particulate matter control device. The 
current interim standard is a regulatory limit that is relevant in 
identifying the floor level because it fixes a level of performance for 
new cement kilns. Given that all sources are achieving this interim 
standard and that the interim standard is judged as more stringent than 
the calculated MACT floor, the dioxin/furan floor level can be no less 
stringent than the current regulatory limit. We are, therefore, 
proposing the dioxin/furan floor level as 0.20 ng TEQ/dscm or 0.40 ng 
TEQ/dscm and control of flue gas temperature not to exceed 400[deg]F at 
the inlet to the particulate matter control device.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated activated carbon injection as beyond-the-floor control 
for further reduction of dioxin/furan emissions. We evaluated a beyond-
the-floor level of 0.10 ng TEQ/dscm, which represents a 75% reduction 
in dioxin/furan emissions from the floor level. We selected this level 
because it represents a level that is considered routinely achievable 
with activated carbon injection. In addition, we assumed for costing 
purposes that a new cement kiln will install the activated carbon 
injection system after the existing particulate matter control device 
and add a new, smaller baghouse to remove the injected carbon with the 
adsorbed dioxin/furan. The incremental annualized compliance cost for a 
new cement kiln to meet this beyond-the-floor level, rather than comply 
with the floor level, would be approximately $1.0 million and would 
provide an incremental reduction in dioxin/furan emissions of 
approximately 0.17 grams TEQ per year, for a cost-effectiveness of $5.8 
million per gram of dioxin/furan removed. Nonair quality health and 
environmental impacts and energy effects were not significant factors. 
For these reasons, we are not proposing a beyond-the-floor standard 
based on activated carbon injection for new cement kilns. Therefore, we 
are proposing the standard as 0.20 ng TEQ/dscm or 0.40 ng TEQ/dscm or 
control of flue gas temperature not to exceed 400[deg]F at the inlet to 
the particulate matter control device.

B. What Are the Proposed Standards for Mercury?

    We are proposing to establish standards for existing and new cement 
kilns that limit emissions of mercury to 64 and 35 [mu]g/dscm, 
respectively. If we were to adopt these standards, then sources would 
comply with the limit on an annual basis because the standards are 
based on normal emissions data.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Mercury emissions for existing cement kilns are currently limited 
to 120 [mu]g/dscm by Sec.  63.1204(a)(2).\93\ This standard was 
promulgated in the Interim Standards Rule (See 67 FR at 6796). None of 
the cement kilns burning hazardous waste use a dedicated control device 
to remove mercury from the gas stream; however, kilns control the feed 
concentration of mercury in the hazardous waste.
---------------------------------------------------------------------------

    \93\ An alternative mercury standard is available for existing 
cement kilns whereby a source can elect to comply with a hazardous 
waste maximum theoretical emissions concentration or MTEC of mercury 
of 120 [mu]g/dscm. MTEC is a term 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 units of [mu]g/dscm.
---------------------------------------------------------------------------

    We have emissions data for all sources. All of these data are best 
classified as from normal operations, although, as explained below, 
there is a substantial range within these data. For most sources, we 
have normal emissions data from more than one test campaign. The normal 
mercury stack emissions in our data base range from less than 2 to 118 
[mu]g/dscm. These emissions are expressed as mass of mercury (from all 
feedstocks) per unit volume of stack gas.
    To identify the MACT floor, we evaluated all normal emissions data 
using the SRE/Feed Approach. We considered normal emissions data from 
all test campaigns.\94\ For example, one source in our data base has 
normal emissions data for three different testing campaigns: 1992, 
1995, and 1998. Under this approach we would consider the emissions 
data from the three separate years or campaigns. We believe this 
approach better captures the range of average emissions for a source 
than only considering the most recent normal emissions. Given that no 
cement kilns burning hazardous waste use a control device which 
captures mercury from the flue gas stream, for purposes of this 
analysis we assumed all sources achieved a SRE of zero. The effect of 
this assumption is that the sources with the lowest mercury 
concentrations in the hazardous waste were identified as the best 
performing sources.
---------------------------------------------------------------------------

    \94\ Given that we only have normal feedrate and emissions data 
for mercury for cement kilns, we do not believe it is appropriate to 
establish a hazardous waste thermal emissions-based standard. We 
prefer to establish emission standards under the hazardous waste 
thermal emissions format using compliance test data because the 
metals feedrate information from compliance tests that we use to 
apportion emissions to calculate emissions attributable to hazardous 
waste are more reliable than feedrate data measured during testing 
under normal, typical operations.
---------------------------------------------------------------------------

    The calculated floor is 64 [mu]g/dscm, which considers emissions 
variability, based on a hazardous waste maximum theoretical emissions 
concentration (MTEC) of 26 [mu]g/dscm. This is an emission level that 
the average of the best performing sources could be expected to achieve 
in 99 of 100 future tests when operating under conditions identical to 
the compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 59% 
of sources and would reduce mercury emissions by 0.23 tons per year. If 
we were to adopt such a floor level, we are proposing that sources 
comply with the limit on an annual basis because it is based on normal 
emissions data. Under this approach,

[[Page 21251]]

compliance would not be based on the use of a total mercury continuous 
emissions monitoring system because these monitors have not been 
adequately demonstrated as a reliable compliance assurance tool at 
cement kiln sources. Instead, a source would maintain compliance with 
the mercury standard by establishing and complying with short-term 
limits on operating parameters for pollution control equipment and 
annual limits on maximum total mercury feedrate in all feedstreams.
    We did not use the stack emissions data of preheater/precalciner 
kilns in the floor analysis because we believe the mercury emissions 
are biased low when the in-line raw mill is on-line and biased high 
when the in-line raw mill is off-line. (See earlier discussion on why 
we are proposing not to subcategorize hazardous waste burning cement 
kilns for mercury between wet process kilns and preheater/precalciner 
kilns with in-line raw mills.) For either case, we believe the normal 
mercury data are not representative of average emissions and, 
therefore, not appropriate to include in the floor analysis. We request 
comment on this data handling decision.
    In the September 1999 final rule, we acknowledged that a cement 
kiln using properly designed and operated MACT control technologies, 
including controlling the levels of metals in the hazardous waste, may 
not be capable of achieving a given emission standard because of 
mineral and process raw material contributions that might cause an 
exceedance of the emission standard. To address this concern, we 
promulgated a provision that allows kilns to petition for alternative 
standards provided they submit site-specific information that shows raw 
material hazardous air pollutant contributions to the emissions prevent 
the source from complying with the emission standard even though the 
kiln is using MACT control. See Sec.  63.1206(b)(10).
    Today's proposed floor of 64 [mu]g/dscm, which was based on a 
hazardous waste MTEC of 26 [mu]g/dscm, may likewise necessitate such an 
alternative because contributions of mercury in the raw materials and 
fossil fuels at some sources may cause an exceedance of the emission 
standard. The Agency intends to retain a source's ability to comply 
with an alternative standard, and we request comment on two approaches 
to accomplish this. The first approach would be to structure the 
alternative standard similar to the petitioning process used under 
Sec.  63.1206(b)(10). In the case of mercury for an existing cement 
kiln, MACT would be defined as a hazardous waste feedrate corresponding 
to an MTEC of 26 [mu]g/dscm. If we were to adopt this approach, we 
would require sources, upon approval of the petition by the 
Administrator, to comply with this hazardous waste MTEC on an annual 
basis because it is based on normal emissions data. Under the second 
approach, we would structure the alternative standard similar to the 
framework used for the alternative interim standards for mercury under 
Sec.  63.1206(b)(15). The operating requirement would be an annual MTEC 
not to exceed 26 [mu]g/dscm. We also request comment on whether there 
are other approaches that would more appropriately provide relief to 
sources that cannot achieve a total stack gas concentration standard 
because of emissions attributable to raw material and nonhazardous 
waste fuels.
    In June 2003, the Cement Kiln Recycling Coalition (CKRC) \95\ 
submitted to EPA information on actual mercury concentrations in the 
hazardous waste burn tanks of all 14 cement facilities for a three year 
period covering 1999 to 2001. In general, the information shows the 
mercury concentration (in parts per million) in the hazardous waste for 
each burn tank.\96\ In total, approximately 20,000 mercury burn tank 
concentration data points are included in CKRC's submission.\97\ The 
data show that approximately 50% of the individual burn tank 
measurements are 0.6 ppmw or less, 75% are less than 1.1 ppmw, 88% are 
less than 2 ppmw, and 97% of all burn tank measurements are less than 5 
ppmw. For a hypothetical wet process cement kiln that gets 50% of its 
required heat input from hazardous waste, a hazardous waste with a 
mercury concentration of 0.6 ppmw equates approximately to an 
uncontrolled (i.e., a system removal efficiency of zero) stack gas 
concentration of 24 [mu]g/dscm. This estimated stack gas concentration, 
of course, does not include contributions to emissions from other 
mercury-containing feedstocks including raw materials and fossil fuels. 
Mercury concentrations of 1.1, 2, and 5 ppmw in the hazardous waste 
equate to uncontrolled stack gas concentrations of approximately 43, 
79, and 196 [mu]g/dscm.\98\
---------------------------------------------------------------------------

    \95\ Cement Kiln Recycling Coalition is a trade organization 
that represents cement companies that burn hazardous wastes as a 
fuel. CKRC also represents companies that manage and market 
hazardous waste fuels used in cement kilns.
    \96\ For two cement facilities, the mercury concentration data 
are only available on a monthly-averaged basis.
    \97\ Data from three of the facilities had a significant number 
of individual measurements reported as not detectable and also had 
relatively high analysis detection limits (compared to levels 
achieved by other cement plants). The detection limit for most 
cement kilns was typically 0.1 ppm or less. For purposes of today's 
preamble discussion, the measurements from these three cement plants 
are excluded from the data characterization conclusions.
    \98\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards,'' 
March 2004, Chapter 23.
---------------------------------------------------------------------------

    We compared the concentration of mercury in the hazardous waste 
associated with the normal emissions data in our data base to the 3-
year historical burn tank concentration data to estimate whether the 
normal data in our data base--the basis of today's proposed floor of 64 
[mu]g/dscm--are likely to represent the high end, low end, or close to 
average emissions. Mercury feed concentration information is not 
available for every test condition; however, the mercury concentrations 
in the hazardous waste burned by the best performing sources during the 
tests that generated the normal emissions ranged from 0.1 to 0.44 ppmw. 
For the best performing sources comprising the MACT pool for which we 
can make a comparison, it appears that the normal concentrations in the 
hazardous waste during testing represent the low end (15th percentile 
or less) of average mercury concentrations. We invite comment on 
whether the normal emissions data in our data base are representative 
of average emissions in practice and whether evaluating the data to 
identify a floor level is appropriate.
    In addition, we request comment on how to identify a floor level 
using the 3-year hazardous waste mercury concentration data. One 
potential approach would be to establish a hazardous waste feed 
concentration standard expressed in ppmw. To identify a floor level 
expressed as a hazardous waste feed concentration in ppmw, we 
identified and evaluated the 3-year historical burn tank concentration 
data of the five best performing facilities (those sources with the 
lowest mean concentration considering variability). The calculated 
alternative floor level is 2.2 ppmw in the hazardous waste. To put this 
in context for a hypothetical wet process cement kiln that gets 50% of 
its required heat input from hazardous waste, a mercury concentration 
of 2.2 ppmw in the hazardous waste equates approximately to an 
uncontrolled stack gas concentration of 86 [mu]g/dscm.\99\ This

[[Page 21252]]

estimated stack gas concentration, of course, does not include 
contributions to emissions from other mercury-containing feedstocks 
such as raw materials and fossil fuels. If we were to adopt such an 
approach, we would require sources to comply with the feed 
concentration standard on a short term basis (e.g., 12 hour average).
---------------------------------------------------------------------------

    \99\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards'', 
March 2004, Chapter 23.
---------------------------------------------------------------------------

    We also invite comment on whether we should judge an annual limit 
of 64 [mu]g/dscm as less stringent than either the current emission 
standard of 120 [mu]g/dscm or the hazardous waste MTEC of mercury of 
120 [mu]g/dscm for cement kilns (so as to avoid any backsliding from a 
current level of performance achieved by all sources, and hence, the 
level of minimal stringency at which EPA could calculate the MACT 
floor). In order to comply with the current emission standard, 
generally a source must conduct manual stack sampling to demonstrate 
compliance with the mercury emission standard and then establish a 
maximum mercury feedrate limit based on operations during the 
performance test. Following the performance test, the source complies 
with a limit on the maximum total mercury feedrate in all feedstreams 
on a 12-hour rolling average (not an annual average). Alternatively, a 
source can elect to comply with a hazardous waste MTEC of mercury of 
120 [mu]g/dscm that would require the source to limit the mercury 
feedrate in the hazardous waste on a 12-hour rolling average. The floor 
level of 64 [mu]g/dscm proposed today would allow a source to feed more 
variable mercury-containing feedstreams (e.g., a hazardous waste with 
an mercury MTEC greater than 120 [mu]g/dscm) than the current 12-hour 
rolling average because today's proposed floor level is an annual 
limit. For example, we estimated a hazardous waste MTEC for each burn 
tank measurement associated with the 3-year historical concentration 
data submitted by CKRC. We found that approximately 5% of burn tank 
measurements would exceed a hazardous waste MTEC of 120 [mu]g/dscm, 
including sources upon which the proposed floor is based.\100\
---------------------------------------------------------------------------

    \100\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards'', 
March 2004, Chapter 23.
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified three potential beyond-the-floor techniques for 
control of mercury: (1) Activated carbon injection; (2) control of 
mercury in the hazardous waste feed; and (3) control of mercury in the 
raw materials and auxiliary fuels. For reasons discussed below, we are 
not proposing a beyond-the-floor standard for mercury.
    Use of Activated Carbon Injection. We evaluated activated carbon 
injection as beyond-the-floor control for further reduction of mercury 
emissions. Activated carbon has been demonstrated for controlling 
mercury in several combustion applications; however, currently no 
cement kiln that burns hazardous waste uses activated carbon injection. 
Given this lack of experience using activated carbon injection, we made 
a conservative assumption that the use of activated carbon injection 
will provide 70% mercury control and evaluated a beyond-the-floor level 
of 19 [mu]g/dscm. In addition, for costing purposes we assumed that 
cement kilns needing activated carbon injection to achieve the beyond-
the-floor level would install the activated carbon injection system 
after the existing particulate matter control device and add a new, 
smaller baghouse to remove the injected carbon with the adsorbed 
mercury. We chose this costing approach to address potential concerns 
that injected carbon may interfere with cement kiln dust recycling 
practices.
    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 $16.8 million and would provide 
an incremental reduction in mercury emissions beyond the MACT floor 
controls of 0.41 tons per year. Nonair quality health and environmental 
impacts and energy effects were evaluated to estimate the impacts 
between activated carbon injection and controls likely to be used to 
meet the floor level. We estimate that this beyond-the-floor option 
would increase the amount of solid waste generated by 4,400 tons per 
year and would require sources to use an additional 21 million kW-hours 
per year beyond the requirements to achieve the floor level. The costs 
associated with these impacts are accounted for in the national 
annualized compliance cost estimates. Therefore, based on these factors 
and costs of approximately $41 million per additional ton of mercury 
removed, we are not proposing a beyond-the-floor standard based on 
activated carbon injection.
    Feed Control of Mercury in the Hazardous Waste. We also evaluated a 
beyond-the-floor level of 51 [mu]g/dscm, which represents a 20% 
reduction from the floor level. We chose a 20% reduction as a level 
representing the practicable extent that additional feedrate control of 
mercury in hazardous waste (beyond feedrate control that may be 
necessary to achieve the floor level) can be used and still achieve 
modest emissions reductions.\101\ 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 $3.7 
million and would provide an incremental reduction in mercury emissions 
beyond the MACT floor controls of 180 pounds per year. Nonair quality 
health and environmental impacts and energy effects were also 
evaluated. Therefore, based on these factors and costs of approximately 
$42 million per additional ton of mercury removed, we are not proposing 
a beyond-the-floor standard based on feed control of mercury in the 
hazardous waste.
---------------------------------------------------------------------------

    \101\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume V: Emission Estimates and Engineering 
Costs'', March 2004, Chapter 4.
---------------------------------------------------------------------------

    Feed Control of Mercury in the Raw Materials and Auxiliary Fuels. 
Cement kilns could achieve a reduction in mercury emissions by 
substituting a raw material containing lower levels of mercury for a 
primary raw material with a higher level. We believe that this beyond-
the-floor option would be even less cost-effective than either of the 
options discussed above, however. Given that sources are sited near the 
supply of the primary raw material, transporting large quantities of an 
alternate source of raw materials is likely to be cost-prohibitive, 
especially considering the small expected emissions reductions that 
would result.
    We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of mercury would be an appropriate 
control option for sources. Given that most cement kilns burning 
hazardous waste also burn coal as a fuel, we considered switching to 
natural gas as a potential beyond-the-floor option. We are concerned 
about the availability of natural gas to all cement kilns because 
natural gas pipelines are not available in all regions of the United 
States. See 68 FR 1673. Moreover, even where pipelines provide access 
to natural gas, supplies of natural gas may not be adequate. For 
example, it is common practice in cities during winter months (or 
periods of peak demand) to prioritize natural gas usage for residential 
areas before industrial usage. Requiring cement kilns to switch to 
natural gas would place an even greater strain on natural gas 
resources. Consequently, even where pipelines exist, some sources may 
not be able to use natural gas during times of limited

[[Page 21253]]

supplies. Thus, natural gas may not be a viable control option for some 
sources. Therefore, we are not proposing a beyond-the-floor standard 
based on limiting mercury in the raw material feed and auxiliary fuels.
    For the reasons discussed above, we propose not to adopt a beyond-
the-floor standard for mercury and propose to establish the emission 
standard for existing cement kilns at 64 [mu]g/dscm. If we were to 
adopt such a standard, we are proposing that sources comply with the 
standard on an annual basis because it is based on normal emissions 
data.
3. What Is the Rationale for the MACT Floor for New Sources?
    Mercury emissions from new cement kilns are currently limited to 
120 [mu]g/dscm by Sec.  63.1204(b)(2). New cement kilns can comply with 
an alternative mercury standard that limits the hazardous waste maximum 
theoretical emissions concentration or MTEC of mercury of 120 [mu]g/
dscm. This standard was promulgated in the Interim Standards Rule (See 
67 FR at 6796).
    The MACT floor for new sources for mercury would be 35 [mu]g/dscm, 
which considers emissions variability, based on a hazardous waste MTEC 
of 5.1 [mu]g/dscm. This is an emission level that the single best 
performing source identified with the SRE/Feed Approach could be 
expected to achieve in 99 of 100 future tests when operating under 
conditions identical to the test conditions during which the emissions 
data were obtained. As for existing sources, we assumed all sources 
equally achieved a SRE of zero. The effect of this assumption is that 
the single source with the lowest mercury concentration in the 
hazardous waste was identified as the best performing source. We also 
invite comment on whether we should judge an annual limit of 35 [mu]g/
dscm as less stringent than either the current emission standard of 120 
[mu]g/dscm or the hazardous waste MTEC of mercury of 120 [mu]g/dscm for 
cement kilns (so as to avoid any backsliding from a current level of 
performance achieved by all sources).
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We identified the same three potential beyond-the-floor techniques 
for control of mercury: (1) Use of activated carbon; (2) control of 
mercury in the hazardous waste feed; and (3) control of the mercury in 
the raw materials and auxiliary fuels.
    Use of Activated Carbon Injection. We evaluated activated carbon 
injection as beyond-the-floor control for further reduction of mercury 
emissions. We made a conservative assumption that the use of activated 
carbon injection will provide 70% mercury control and evaluated a 
beyond-the-floor level of 11 [mu]g/dscm. The incremental annualized 
compliance cost for a new cement kiln to meet this beyond-the-floor 
level, rather than comply with the floor level, would be approximately 
$1.0 million and would provide an incremental reduction in mercury 
emissions of approximately 88 pounds per year. We also estimate that 
this option would increase the amount of solid waste generated by 400 
tons per year and would require sources to use an additional 1.9 
million kW-hours per year. Nonair quality health and environmental 
impacts and energy effects are accounted for in the national annualized 
compliance cost estimates. Therefore, based on these factors and costs 
of $23 million per ton of mercury removed, we are not proposing a 
beyond-the-floor standard based on activated carbon injection for new 
cement kilns.
    Feed Control of Mercury in the Hazardous Waste. We also believe 
that the expense for further reduction in mercury emissions based on 
further control of mercury concentrations in the hazardous waste is not 
warranted. A beyond-the-floor level of 28 ug/dscm, which represents a 
20% reduction from the floor level, would result in little additional 
mercury reductions. For similar reasons discussed above for existing 
sources, we conclude that a beyond-the-floor standard based on 
controlling the mercury in the hazardous waste feed would not be 
justified because of the costs coupled with estimated emission 
reductions.
    Feed Control of Mercury in the Raw Materials and Auxiliary Fuels. 
Cement kilns could achieve a reduction in mercury emissions by 
substituting a raw material containing lower levels of mercury for a 
primary raw material with a higher level. For a new source at an 
existing cement plant, we believe that this beyond-the-floor option 
would not be cost-effective due to the costs of transporting large 
quantities of an alternate source of raw materials to the cement plant. 
Given that the plant site already exists and sited near the source of 
raw material, replacing the raw materials at the plant site with lower 
mercury-containing materials would be the source's only option. For a 
new cement kiln constructed at a new site--a greenfield site \102\--we 
are not aware of any information and data from a source that has 
undertaken or is currently located at a site whose raw materials are 
low in mercury which would consistently decrease mercury emissions. 
Further, we are uncertain as to what beyond-the-floor standard would be 
achievable using a lower, if it exists, mercury-containing raw 
material. Although we are doubtful that selecting a new plant site 
based on the content of metals in the raw material is a realistic 
beyond-the-floor option considering the numerous additional factors 
that go into such a decision, we solicit comment on whether and what 
level of a beyond-the-floor standard based on controlling the level of 
mercury in the raw materials is appropriate.
---------------------------------------------------------------------------

    \102\ A greenfield cement kiln is a kiln constructed at a site 
where no cement kiln previously existed; however, a newly 
constructed or reconstructed cement kiln at an existing site would 
not be considered as a greenfield cement kiln.
---------------------------------------------------------------------------

    We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of mercury would be an appropriate 
control option for sources. We considered using natural gas in lieu of 
a fossil fuel such as coal containing higher concentrations of mercury 
as a potential beyond-the-floor option. As discussed for existing 
sources, we are concerned about the availability of the natural gas 
infrastructure in all regions of the United States and believe that 
using natural gas would not be a viable control option for all new 
sources. Therefore, we are not proposing a beyond-the-floor standard 
based on limiting mercury in the raw material feed and auxiliary fuels.
    Therefore, we propose a mercury standard of 35 ug/dscm for new 
sources. If we were to adopt such a standard, we are proposing that 
sources comply with the standard on an annual basis because it is based 
on normal emissions data.

C. What Are the Proposed Standards for Particulate Matter?

    We are proposing to establish standards for existing and new cement 
kilns that limit emissions of particulate matter to 65 mg/dscm (0.028 
gr/dscf) and 13 mg/dscm (0.0058 gr/dscf), respectively.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Particulate matter emissions for existing cement kilns are 
currently limited to 0.15 kilograms of particulate matter per megagram 
dry feed \103\ and 20% opacity by Sec.  63.1204(a)(7). This standard 
was promulgated in the Interim Standards Rule (See 67 FR at

[[Page 21254]]

6796). The particulate matter standard is a surrogate control for the 
metals antimony, cobalt, manganese, nickel, and selenium in the 
hazardous waste and all HAP metals in the raw materials and auxiliary 
fuels which are controllable by particulate matter control. All cement 
kilns control particulate matter with baghouses and electrostatic 
precipitators.
---------------------------------------------------------------------------

    \103\ This standard equates approximately to a stack gas 
concentration level of 0.030 gr/dscf for wet process kilns and 0.040 
gr/dscf for preheater/precalciner kilns. The conversion varies by 
process type because the amount of flue gas generated per ton of raw 
material feed varies by process type.
---------------------------------------------------------------------------

    We have compliance test emissions data for all cement kiln sources. 
For most sources, we have compliance test emissions data from more than 
one compliance test campaign. Our data base of particulate matter stack 
emission concentrations range from 0.0008 to 0.063 gr/dscf.
    To identify the floor level, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
Air Pollution Control Technology Approach. The calculated floor is 65 
mg/dscm (0.028 gr/dscf), which considers emissions variability. This is 
an emission level that the average of the best performing sources could 
be expected to achieve in 99 of 100 future tests when operating under 
conditions identical to the compliance test conditions during which the 
emissions data were obtained. We estimate that this emission level is 
being achieved by 44% of sources and would reduce particulate matter 
emissions by 43 tons per year.
    We are also proposing to delete the current opacity standard in 
conjunction with revisions to the compliance assurance requirements for 
particulate matter for cement kilns. These proposed compliance 
assurance amendments include requiring a cement kiln source using a 
baghouse to comply with the same bag leak detection system requirements 
that are currently applicable to all other hazardous waste combustors 
(see Sec.  63.1209(m)). A cement kiln source using an ESP has the 
option either to (1) use a particulate matter emissions detector as a 
process monitor in lieu of complying with operating parameter limits, 
as we are proposing for all other hazardous waste combustor sources; or 
(2) establish site-specific, enforceable operating parameter limits 
that are linked to the automatic waste feed cutoff system. See Part 
Three, Section III for a discussion of the proposed changes.
    We also request comment on whether the particulate matter standard 
should be expressed on a concentration basis (as proposed today) or on 
a production-based format. A concentration-based standard is expressed 
as mass of particulate matter per dry standard volume of gas (e.g., mg/
dscm as proposed today) while a production-based standard is expressed 
as mass of particulate matter emitted per mass of dry raw material feed 
to the kiln (e.g., the format of the interim standard). We evaluated 
the compliance test production-based data associated with the most 
recent test campaign to determine what the floor level would be under 
this approach. The calculated floor would be 0.10 kilograms of 
particulate matter per megagram dry feed. We note that a concentration 
format can be viewed as penalizing more energy efficient kilns, which 
burn less fuel and produce less kiln exhaust gas per megagram of dry 
feed. This is because with a concentration-based standard the more 
energy-efficient kilns would be restricted to a lower level of 
particulate matter emitted per unit of production.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated improved particulate matter control to achieve a 
beyond-the-floor standard of 32 mg/dscm (0.014 gr/dscf), which is a 50% 
reduction from MACT floor emissions.\104\ For an existing source that 
needs a significant reduction in particulate matter emissions, we 
assumed and estimated costs for a new baghouse to achieve the beyond-
the-floor level. If little or modest emissions reductions were needed, 
then improved control was costed as design, operation, and maintenance 
modifications of the existing particulate matter control equipment.
---------------------------------------------------------------------------

    \104\ We did not evaluate a beyond-the-floor standard based on 
fuel substitution because particulate matter emissions from cement 
kilns are primarily entrained raw material, not ash contributed by 
the hazardous waste fuel. There is, therefore, no correlation 
between particulate matter emissions and the level of ash in the 
hazardous waste.
---------------------------------------------------------------------------

    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 $4.8 million and would provide an 
incremental reduction in particulate matter emissions beyond the MACT 
floor controls of 385 tons per year. Nonair quality health and 
environmental impacts and energy effects were evaluated to estimate the 
impacts between further improvements to control particulate matter and 
controls likely to be used to meet the floor level. We estimate that 
this beyond-the-floor option would increase the amount of solid waste 
generated by 385 tons per year and would require sources to use an 
additional 15 million kW-hours per year beyond the requirements to 
achieve the floor level. The costs associated with these impacts are 
accounted for in the national annualized compliance cost estimates. 
Therefore, based on these factors and costs of approximately $12,400 
per additional ton of particulate matter removed, we are not proposing 
a beyond-the-floor standard based on improved particulate matter 
control.
3. What Is the Rationale for the MACT Floor for New Sources?
    Particulate matter emissions from new cement kilns are currently 
limited to 0.15 kilograms of particulate matter per megagram dry feed 
and 20% opacity by Sec.  63.1204(b)(7). This standard was promulgated 
in the Interim Standards Rule (See 67 FR at 6796).
    The MACT floor for new sources for particulate matter would be 13 
mg/dscm (0.0058 gr/dscf), which considers emissions variability. This 
is an emission level that the single best performing source identified 
with the Air Pollution Control Technology Approach could be expected to 
achieve in 99 of 100 future tests when operating under operating 
conditions identical to the test conditions during which the emissions 
data were obtained. We are also proposing to delete the current opacity 
standard in conjunction with revisions to the compliance assurance 
requirements for particulate matter for cement kilns. See Part Three, 
Section III for details.
    As discussed for existing sources, we also request comment on 
whether the particulate matter standard should be expressed on a 
concentration basis or on a production-based format. We evaluated the 
compliance test production-based data associated with the most recent 
test campaign to determine what the floor level would be under this 
approach. The calculated floor would be 0.028 kilograms of particulate 
matter per megagram dry feed.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated improved emissions control based on a state-of-the-art 
baghouse using a high quality fabric filter bag material to achieve a 
beyond-the-floor standard of 6.7 mg/dscm (0.0029 gr/dscf). This 
reduction represents a 50% reduction in particulate matter emissions 
from MACT floor levels. The incremental annualized compliance cost for 
a new cement kiln to meet this beyond-the-floor level, rather than 
comply with the floor level, would be approximately $0.38 million and 
would provide an incremental reduction in particulate matter emissions 
of approximately 2.6 tons per year. We estimate that this

[[Page 21255]]

beyond-the-floor option would increase the amount of solid waste 
generated by less than 6 tons per year and would require sources to use 
an additional 1.8 million kW-hours per year beyond the requirements to 
achieve the floor level. The costs associated with these impacts are 
accounted for in the national annualized compliance cost estimates. 
Therefore, based on these factors and costs of approximately $61,400 
per additional ton of particulate matter removed, we are not proposing 
a beyond-the-floor standard based on improved particulate matter 
control for new cement kilns. Therefore, we propose a particulate 
matter standard of 13 mg/dscm for new sources.

D. What Are the Proposed Standards for Semivolatile Metals?

    We are proposing to establish standards for existing cement kilns 
that limit emissions of semivolatile metals (cadmium and lead, 
combined) to 4.0 x 10-4 lbs semivolatile metals emissions 
attributable to the hazardous waste per million Btu heat input of the 
hazardous waste. The proposed standard for new sources is 6.2 x 
10-5 lbs semivolatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Semivolatile metals emissions from existing cement kilns are 
currently limited to 330 [mu]g/dscm by Sec.  63.1204(a)(3). This 
standard was promulgated in the Interim Standards Rule (See 67 FR at 
6796). Cement kilns control emissions of semivolatile metals with 
baghouses or electrostatic precipitators and/or by controlling the feed 
concentration of semivolatile metals in the hazardous waste.
    We have compliance test emissions data for all cement kiln sources. 
For most sources, we have compliance test emissions data from more than 
one compliance test campaign. Semivolatile metal stack emissions range 
from approximately 1 to 2,800 [mu]g/dscm. These emissions are expressed 
as mass of semivolatile metals (from all feedstocks) per unit volume of 
stack gas. Hazardous waste thermal emissions range from 3.0 x 
10-6 to 3.7 x 10-3 lbs per million Btu. Hazardous 
waste thermal emissions represent the mass of semivolatile metals 
emissions attributable to the hazardous waste per million Btu heat 
input of the hazardous waste. Lead was the most significant contributor 
to semivolatile emissions during compliance test conditions.
    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 4.0 x 10-4 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste, which considers 
emissions variability. This is an emission level that the average of 
the best performing sources could be expected to achieve in 99 of 100 
future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 81% 
of sources and would reduce semivolatile metals emissions by 1 ton per 
year.
    To put the proposed floor level in context for a hypothetical wet 
process cement kiln that gets 50% of its required heat input from 
hazardous waste, a thermal emissions level of 4.0 x 10-4 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste equates approximately to 
a stack gas concentration of 180 [mu]g/dscm. This estimated stack gas 
concentration does not include contributions to emission from other 
semivolatile metals-containing materials such as raw materials and 
fossil fuels. The additional contribution to stack emissions of 
semivolatile metals in an average raw material and coal is estimated to 
range as high as 20 to 50 [mu]g/dscm. Thus, for the hypothetical wet 
process cement kiln the thermal emissions floor level of 4.0 x 
10-4 lbs semivolatile metals attributable to the hazardous 
waste per million Btu heat input of the hazardous waste is estimated to 
be less than 230 [mu]g/dscm, which is less than the current interim 
standard of 330 [mu]g/dscm. Given that comparing the proposed floor 
level to the interim standard requires numerous assumptions (as just 
illustrated) including hazardous waste fuel replacement rates, heat 
input requirements per ton of clinker, concentrations of semivolatile 
metals in the raw material and coal, and system removal efficiency, we 
have a more detailed analysis in the background document.\105\ Our 
detailed analysis indicates the proposed floor level is at least as 
stringent as the interim standard (so as to avoid any backsliding from 
a current level of performance achieved by all cement kilns, and hence, 
the level of minimal stringency at which EPA could calculate the MACT 
floor). Thus, we conclude that a dual standard--the semivolatile metals 
standard as both the calculated floor level, expressed as a hazardous 
waste thermal emissions level, and the current interim standard--is not 
needed for this standard.
---------------------------------------------------------------------------

    \105\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards,'' 
March 2004, Chapter 23.
---------------------------------------------------------------------------

    In the September 1999 final rule, we acknowledged that a cement 
kiln using properly designed and operated MACT control technologies, 
including controlling the levels of metals in the hazardous waste, may 
not be capable of achieving a given emission standard because of 
mineral and process raw material contributions that might cause an 
exceedance of the emission standard. To address this concern, we 
promulgated a provision that allows 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 source from complying with the emission standard 
even though the kiln is using MACT control. See Sec.  63.1206(b)(10). 
If we were to adopt the semivolatile (and low volatile) metals standard 
using a thermal emissions format, then there would be no need for these 
alternative standard provisions for semivolatile metals (since, as 
explained earlier, that standard is based solely on semivolatile metals 
contributions from hazardous waste fuels). Therefore, we would delete 
the provisions of Sec.  63.1206(b)(10) as they apply to semivolatile 
(and low volatile) metals. We invite comment on this approach.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified three potential beyond-the-floor techniques for 
control of semivolatile metals: (1) Improved particulate matter 
control; (2) control of semivolatile metals in the hazardous waste 
feed; and (3) control of the semivolatile metals in the raw materials 
and fuels. For reasons discussed below, we are not proposing a beyond-
the-floor standard for semivolatile metals.
    Improved Particulate Matter Control. Controlling particulate matter 
also controls emissions of semivolatile metals. Our data show that all 
cement kilns are already achieving greater than 98.6% system removal 
efficiency for semivolatile metals, with most attaining 99.9% removal. 
Thus, additional controls of particulate matter are likely to result in 
only modest additional reductions of semivolatile metals emissions. We 
evaluated a beyond-the-floor level of 2.0 x 10-4 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste, which

[[Page 21256]]

represents a 50% reduction in emissions from MACT floor levels. 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 $2.7 million and would provide an 
incremental reduction in semivolatile metals emissions beyond the MACT 
floor controls of 1.2 tons per year. Nonair quality health and 
environmental impacts and energy effects were evaluated to estimate the 
impacts between further improvements to control particulate matter and 
controls likely to be used to meet the floor level. We estimate that 
this beyond-the-floor option would increase the amount of solid waste 
generated by 300 tons per year and would also require sources to use an 
additional 5.7 million kW-hours of energy per year to achieve the floor 
level. The costs associated with these impacts are accounted for in the 
national annualized compliance cost estimates. Therefore, based on 
these factors and costs of approximately $2.3 million per additional 
ton of semivolatile metals removed, we are not proposing a beyond-the-
floor standard based on improved particulate matter control.
    Feed Control of Semivolatile Metals in the Hazardous Waste. We also 
evaluated a beyond-the-floor level of 3.2 x 10-4 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste, which represents a 20% 
reduction from the floor level. We chose a 20% reduction as a level 
representing the practicable extent that additional feedrate control of 
semivolatile metals in hazardous waste can be used and still achieve 
appreciable emissions reductions. 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 $0.30 
million and would provide an incremental reduction in semivolatile 
metals emissions beyond the MACT floor controls of 0.36 tons per year. 
Nonair quality health and environmental impacts and energy effects were 
evaluated and are included in the national compliance cost estimates. 
Therefore, based on these factors and costs of approximately $0.84 
million per additional ton of semivolatile metals removed, we are not 
proposing a beyond-the-floor standard based on feed control of 
semivolatile metals in the hazardous waste.
    Feed Control of Semivolatile Metals in the Raw Materials and 
Auxiliary Fuels. Cement kilns could achieve a reduction in semivolatile 
metal emissions by substituting a raw material containing lower levels 
of lead and/or cadmium for a primary raw material with higher levels of 
these metals. We believe that this beyond-the-floor option would even 
be less cost-effective than either of the options discussed above, 
however. Given that cement kilns are sited near the primary raw 
material supply, acquiring and transporting large quantities of an 
alternate source of raw materials is likely to be cost-prohibitive. 
Therefore, we are not proposing a beyond-the-floor standard based on 
limiting semivolatile metals in the raw material feed. We also 
considered whether fuel switching to an auxiliary fuel containing a 
lower concentration of semivolatile metals would be an appropriate 
control option for sources. Given that most cement kilns burning 
hazardous waste also burn coal as a fuel, we considered switching to 
natural gas as a potential beyond-the-floor option. For the same 
reasons discussed for mercury, we judge a beyond-the-floor standard 
based on fuel switching as unwarranted.
    For the reasons discussed above, we propose to establish the 
emission standard for existing cement kilns at 4.0 x 10-4 
lbs semivolatile metals emissions attributable to the hazardous waste 
per million Btu heat input of the hazardous waste.
3. What Is the Rationale for the MACT Floor for New Sources?
    Semivolatile metals emissions from new cement kilns are currently 
limited to 180 [mu]g/dscm by Sec.  63.1204(b)(3). This standard was 
promulgated in the Interim Standards Rule (See 67 FR at 6796).
    The MACT floor for new sources for semivolatile metals would be 6.2 
x 10-5 lbs semivolatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste, 
which considers emissions variability. This is an emission level that 
the single best performing source identified with the SRE/Feed Approach 
could be expected to achieve in 99 of 100 future tests when operating 
under conditions identical to the test conditions during which the 
emissions data were obtained.
    To put the proposed floor level in context for a hypothetical wet 
process cement kiln that gets 50% of its required heat input from 
hazardous waste, a thermal emissions level of 6.2 x 10-5 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste equates approximately to 
a stack gas concentration of 80 [mu]g/dscm, including contributions 
from typical raw materials and coal. Thus, for the hypothetical wet 
process cement kiln the thermal emissions floor level of 6.2 x 
10-5 lbs semivolatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste is 
estimated to be less than the current interim standard for new sources 
of 180 [mu]g/dscm.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We identified the same three potential beyond-the-floor techniques 
for control of semivolatile metals: (1) Improved control of particulate 
matter; (2) control of semivolatile metals in the hazardous waste feed; 
and (3) control of semivolatile metals in the raw materials and fuels.
    Improved Particulate Matter Control. Controlling particulate matter 
also controls emissions of semivolatile metals. We evaluated improved 
control of particulate matter based on a state-of-the-art baghouse 
using a high quality fabric filter bag material as beyond-the-floor 
control for further reductions in semivolatile metals emissions. We 
evaluated a beyond-the-floor level of 2.5 x 10-5 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste. The incremental 
annualized compliance cost for a new cement kiln with an average gas 
flow rate to meet this beyond-the-floor level, rather than to comply 
with the floor level, would be approximately $0.38 million and would 
provide an incremental reduction in semivolatile metals emissions of 
approximately 144 pounds per year. Nonair quality health and 
environmental impacts and energy effects were evaluated and are 
included in the cost estimates. For these reasons and costs of $5.3 
million per ton of semivolatile metals removed, we are not proposing a 
beyond-the-floor standard based on improved particulate matter control 
for new cement kilns.
    Feed Control of Semivolatile Metals in the Hazardous Waste. We also 
believe that the expense for further reduction in semivolatile metals 
emissions based on further control of semivolatile metals 
concentrations in the hazardous waste is not warranted. We also 
evaluated a beyond-the-floor level of 5.0 x 10-5 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste, which represents a 20% 
reduction from the floor level. Nonair quality health and environmental 
impacts and energy effects were evaluated and are included in the 
compliance cost estimates. For similar

[[Page 21257]]

reasons discussed above for existing sources, we conclude that a 
beyond-the-floor standard based on controlling the concentration of 
semivolatile metals levels in the hazardous waste feed would not be 
justified because of the costs coupled with estimated emission 
reductions.
    Feed Control of Semivolatile Metals in the Raw Materials and 
Auxiliary Fuels. Cement kilns could achieve a reduction in semivolatile 
metals emissions by substituting a raw material containing lower levels 
of cadmium and lead for a primary raw material with a higher level. For 
a new source at an existing cement plant, we believe that this beyond-
the-floor option would not be cost-effective due to the costs of 
transporting large quantities of an alternate source of raw materials 
to the cement plant. Given that the plant site already exists and sited 
near the source of raw material, replacing the raw materials at the 
plant site with lower semivolatile metals-containing materials would be 
the source's only option. For a cement kiln constructed at a new 
greenfield site, we are not aware of any information and data from a 
source that has undertaken or is currently located at a site whose raw 
materials are inherently lower in semivolatile metals that would 
consistently achieve reduced semivolatile metals emissions. Further, we 
are uncertain as to what beyond-the-floor standard would be achievable 
using a lower, if it exists, semivolatile metals-containing raw 
material. Although we are doubtful that selecting a new plant site 
based on the content of metals in the raw material is a realistic 
beyond-the-floor option considering the numerous additional factors 
that go into such a decision, we solicit comment on whether and what 
level of a beyond-the-floor standard based on controlling the level of 
semivolatile metals in the raw materials is appropriate.
    We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of semivolatile metals would be an 
appropriate control option for sources. Given that most cement kilns 
burning hazardous waste also burn coal as a fuel, we considered 
switching to natural gas as a potential beyond-the-floor option. For 
the same reasons discussed for mercury, we judge a beyond-the-floor 
standard based on fuel switching as unwarranted.
    For the reasons discussed above, we propose to establish the 
emission standard for new cement kilns at 6.2 x 10-5 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste.

E. What Are the Proposed Standards for Low Volatile Metals?

    We are proposing to establish standards for existing and new cement 
kilns that limit emissions of low volatile metals (arsenic, beryllium, 
and chromium, combined) to 1.4 x 10-5 lbs low volatile 
metals emissions attributable to the hazardous waste per million Btu 
heat input of the hazardous waste.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Low volatile metals emissions from existing cement kilns are 
currently limited to 56 [mu]g/dscm by Sec.  63.1204(a)(4). This 
standard was promulgated in the Interim Standards Rule (see 67 FR at 
6796). Cement kilns control emissions of low volatile metals with 
baghouses or electrostatic precipitators and/or by controlling the feed 
concentration of low volatile metals in the hazardous waste.
    We have compliance test emissions data for all cement kiln sources. 
For most sources, we have compliance test emissions data from more than 
one compliance test campaign. Low volatile metal stack emissions range 
from approximately 1 to 100 [mu]g/dscm. These emissions are expressed 
as mass of low volatile metals (from all feedstocks) per unit volume of 
stack gas. Hazardous waste thermal emissions range from 9.2 x 
10-7 to 1.0 x 10-5 lbs per million Btu. Hazardous 
waste thermal emissions represent the mass of low volatile metals 
emissions attributable to the hazardous waste per million Btu heat 
input of the hazardous waste. For nearly every cement kiln, chromium 
was the most significant contributor to low volatile emissions.
    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 1.4 x 10-5 lbs 
low volatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste, which considers 
emissions variability. This is an emission level that the average of 
the best performing sources could be expected to achieve in 99 of 100 
future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 52% 
of sources and would reduce low volatile metals emissions by 0.10 tons 
per year.
    To put the proposed floor level in context for a hypothetical wet 
process cement kiln that gets 50% of its required heat input from 
hazardous waste, a thermal emissions level of 1.4 x 10-5 lbs 
low volatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste equates approximately to 
a stack gas concentration of 7 [mu]g/dscm. This estimated stack gas 
concentration does not include contributions to emission from other low 
volatile metals-containing materials such as raw materials and fossil 
fuels. The additional contribution to stack emissions of low volatile 
metals in an average raw material and coal is estimated to range from 
less than 1 to 15 [mu]g/dscm. Thus, for the hypothetical wet process 
cement kiln the thermal emissions floor level of 1.4 x 10-5 
lbs low volatile metals attributable to the hazardous waste per million 
Btu heat input of the hazardous waste is estimated to be less than 22 
[mu]g/dscm, which is less than the current interim standard of 56 
[mu]g/dscm. Given that comparing the proposed floor level to the 
interim standard requires numerous assumptions (as just illustrated) 
including hazardous waste fuel replacement rates, heat input 
requirements per ton of clinker, concentrations of low volatile metals 
in the raw material and coal, and system removal efficiency, we have 
included a more detailed analysis in the background document.\106\ Our 
detailed analysis indicates the proposed floor level is as least as 
stringent as the interim standard (so as to avoid any backsliding from 
a current level of performance achieved by all cement kilns, and hence, 
the level of minimal stringency at which EPA could calculate the MACT 
floor). Thus, we conclude that a dual standard--the low volatile metals 
standard as both the calculated floor level, expressed as a hazardous 
waste thermal emissions level, and the current interim standard--is not 
needed for this standard.
---------------------------------------------------------------------------

    \106\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards,'' 
March 2004, Chapter 23.
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified three potential beyond-the-floor techniques for 
control of low volatile metals: (1) Improved particulate matter 
control; (2) control of low volatile metals in the hazardous waste 
feed; and (3) control of the low volatile metals in the raw materials. 
For reasons discussed below, we are not proposing a beyond-the-floor 
standard for low volatile metals.

[[Page 21258]]

    Improved Particulate Matter Control. Controlling particulate matter 
also controls emissions of low volatile metals. Our data show that all 
cement kilns are already achieving greater than 99.9% system removal 
efficiency for low volatile metals, with most attaining 99.99% removal. 
Thus, additional control of particulate matter emissions is likely to 
result in only a small increment in reduction of low volatile metals 
emissions. We evaluated a beyond-the-floor level of 7.0 x 
10-6 lbs low volatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste, 
which represents a 50% reduction in emissions from MACT floor levels. 
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 $3.7 million and would provide an 
incremental reduction in low volatile metals emissions beyond the MACT 
floor controls of 120 pounds per year. Nonair quality health and 
environmental impacts and energy effects were evaluated to estimate the 
impacts between further improvements to control particulate matter and 
controls likely to be used to meet the floor level. We estimate that 
this beyond-the-floor option would increase the amount of solid waste 
generated by 72 tons per year and would also require sources to use an 
additional 1.2 million kW-hours per year beyond the requirements to 
achieve the floor level. The costs associated with these impacts are 
accounted for in the national annualized compliance cost estimates. 
Therefore, based on these factors and costs of approximately $63 
million per additional ton of low volatile metals removed, we are not 
proposing a beyond-the-floor standard based on improved particulate 
matter control.
    Feed Control of Low Volatile Metals in the Hazardous Waste. We also 
evaluated a beyond-the-floor level of 1.1 x 10-5 lbs low 
volatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste, which represents a 20% 
reduction from the floor level. We chose a 20% reduction as a level 
representing the practicable extent that additional feedrate control of 
mercury in hazardous waste can be used and still achieve appreciable 
emissions reductions. 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 $1.2 million and 
would provide an incremental reduction in low volatile metals emissions 
beyond the MACT floor controls of 38 pounds per year. Nonair quality 
health and environmental impacts and energy effects were evaluated and 
are included in the cost estimates. Therefore, based on these factors 
and costs of approximately $64 million per additional ton of low 
volatile metals removed, we are not proposing a beyond-the-floor 
standard based on feed control of low volatile metals in the hazardous 
waste.
    Feed Control of Low Volatile Metals in the Raw Materials and 
Auxiliary Fuels. Cement kilns could achieve a reduction in low volatile 
metal emissions by substituting a raw 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 even be less cost-effective than either of the options 
discussed above, however. Given that cement kilns are sited near the 
primary raw material supply, acquiring and transporting large 
quantities of an alternate source of raw materials is likely to be 
cost-prohibitive. Therefore, we are not proposing a beyond-the-floor 
standard based on limiting low volatile metals in the raw material 
feed. We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of low volatile metals would be an 
appropriate control option for sources. Given that most cement kilns 
burning hazardous waste also burn coal as a fuel, we considered 
switching to natural gas as a potential beyond-the-floor option. For 
the same reasons discussed for mercury, we judge a beyond-the-floor 
standard based on fuel switching as unwarranted.
    For the reasons discussed above, we propose to establish the 
emission standard for existing cement kilns at 1.4 x 10-5 
lbs low volatile metals emissions attributable to the hazardous waste 
per million Btu heat input of the hazardous waste.
3. What Is the Rationale for the MACT Floor for New Sources?
    Low volatile metals emissions from new cement kilns are currently 
limited to 54 [mu]g/dscm by Sec.  63.1204(b)(4). This standard was 
promulgated in the Interim Standards Rule (see 67 FR at 6796, February 
13, 2002).
    The floor level for new sources for low volatile metals would be 
1.4 x 10-5 lbs low volatile metals emissions attributable to 
the hazardous waste per million Btu heat input of the hazardous waste, 
which considers emissions variability. This is an emission level that 
the single best performing source identified with the SRE/Feed Approach 
could be expected to achieve in 99 of 100 future tests when operating 
under conditions identical to the test conditions during which the 
emissions data were obtained.
    To put the proposed floor level in context for a hypothetical wet 
process cement kiln that gets 50% of its required heat input from 
hazardous waste, a thermal emissions level of 1.4 x 10-5 lbs 
low volatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste equates approximately to 
a stack gas concentration of 22 [mu]g/dscm, including contributions 
from typical raw materials and coal. Thus, for the hypothetical wet 
process cement kiln the thermal emissions floor level of 6.2 x 
10-\5\ lbs low volatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste is 
estimated to be more stringent than the current interim standard for 
new sources of 54 [mu]g/dscm.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We identified the same three potential beyond-the-floor techniques 
for control of low volatile metals: (1) Improved control of particulate 
matter; (2) control of low volatile metals in the hazardous waste feed; 
and (3) control of low volatile metals in the raw materials and fuels.
    Improved Particulate Matter Control. Controlling particulate matter 
also controls emissions of low volatile metals. We evaluated improved 
control of particulate matter based on a state-of-the-art baghouse 
using a high quality fabric filter bag material as beyond-the-floor 
control for further reductions in low volatile metals emissions. We 
evaluated a beyond-the-floor level of 6.0 x 10-6 lbs low 
volatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste. The incremental 
annualized compliance cost for a new cement kiln to meet this beyond-
the-floor level, rather than comply with the floor level, would be 
approximately $0.38 million and would provide an incremental reduction 
in low volatile metals emissions of approximately 33 pounds per year. 
Nonair quality health and environmental impacts and energy effects were 
evaluated and are included in the cost estimates. For these reasons and 
costs of $23.5 million per ton of low volatile metals removed, we are 
not proposing a beyond-the-floor standard based on improved particulate 
matter control for new cement kilns.

[[Page 21259]]

    Feed Control of Low Volatile Metals in the Hazardous Waste. We also 
evaluated a beyond-the-floor level of 1.1 x 10-5 lbs low 
volatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste, which represents a 20% 
reduction from the floor level. We believe that the expense for further 
reduction in low volatile metals emissions based on further control of 
low volatile metals concentrations in the hazardous waste is not 
warranted given the costs, nonair quality health and environmental 
impacts, and energy effects.
    Feed Control of Low Volatile Metals in the Raw Materials and 
Auxiliary Fuels. Cement kilns could achieve a reduction in low volatile 
metals emissions by substituting a raw material containing lower levels 
of low volatile metals for a primary raw material with a higher level. 
For a new source at an existing cement plant, we believe that this 
beyond-the-floor option would not be cost-effective due to the costs of 
transporting large quantities of an alternate source of raw materials 
to the cement plant. Given that the plant site already exists and sited 
near the source of raw material, replacing the raw materials at the 
plant site with lower low volatile metals-containing materials would be 
the source's only option. For a cement kiln constructed at a new 
greenfield site, we are not aware of any information and data from a 
source that has undertaken or is currently located at a site whose raw 
materials are inherently lower in low volatile metals that would 
consistently achieve reduced low volatile metals emissions. Further, we 
are uncertain as to what beyond-the-floor standard would be achievable 
using a lower, if it exists, low volatile metals-containing raw 
material. Although we are doubtful that selecting a new plant site 
based on the content of metals in the raw material is a realistic 
beyond-the-floor option considering the numerous additional factors 
that go into such a decision, we solicit comment on whether and what 
level of a beyond-the-floor standard based on controlling the level of 
low volatile metals in the raw materials is appropriate.
    We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of low volatile metals would be an 
appropriate control option for sources. Given that most cement kilns 
burning hazardous waste also burn coal as a fuel, we considered 
switching to natural gas as a potential beyond-the-floor option. For 
the same reasons discussed for mercury, we judge a beyond-the-floor 
standard based on fuel switching as unwarranted.
    Therefore, we are proposing a low volatile metals standard of 1.4 x 
10-5 lbs low volatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste.

F. What Are the Proposed Standards for Hydrogen Chloride and Chlorine 
Gas?

    We are proposing to establish standards for existing and new cement 
kilns that limit total chlorine emissions (hydrogen chloride and 
chlorine gas, combined, reported as a chloride equivalent) to 110 and 
83 ppmv, respectively. However, we are also proposing to establish 
alternative risk-based standards, pursuant to CAA section 112(d)(4), 
which could be elected by the source in lieu of the MACT emission 
standards for total chlorine. The emission limits would be based on 
national exposure standards that ensure protection of public health 
with an ample margin of safety. See Part Two, Section XIII for 
additional details.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Total chlorine emissions from existing cement kilns are limited to 
130 ppmv by Sec.  63.1204(a)(6). This standard was promulgated in the 
Interim Standards Rule (See 67 FR at 6796). None of the cement kilns 
burning hazardous waste use a dedicated control device, such as a wet 
scrubber, to remove total chlorine from the gas stream. However, the 
natural alkalinity in some of the raw materials is highly effective at 
removing chlorine from the gas stream. Our data base shows that the 
majority of the system removal efficiency (SRE) data of total 
chlorine--over 80%--indicate a SRE greater than 95%. This scrubbing 
effect, though quite effective, varies across different sources and 
also at individual sources over time due to differences in raw 
materials, operating conditions, cement kiln dust recycle rates, and 
production requirements. Likewise, our data show that total chlorine 
emissions from a given source can vary over a considerable range. Based 
on these data, we conclude that the best (highest) SRE achieved at a 
given source is not duplicable or replicable.
    The majority of the chlorine fed to the cement kiln during a 
compliance test comes from the hazardous waste.\107\ In all but a few 
cases the hazardous waste contribution to the total amount of chlorine 
fed to the kiln represented at least 75% of the total chlorine loading 
to the kiln. As we identified in the September 1999 final rule, the 
proposed MACT floor control for total chlorine is based on controlling 
the concentration of chlorine in the hazardous waste. The chlorine 
concentration in the hazardous waste will affect emissions of total 
chlorine at a given SRE because emissions increase as the chlorine 
loading increases.
---------------------------------------------------------------------------

    \107\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards'', 
March 2004, Chapter 2.
---------------------------------------------------------------------------

    We have compliance test emissions data for all cement kiln sources. 
For most sources, we have compliance test emissions data from more than 
one compliance test campaign. Total chlorine emissions range from less 
than 1 ppmv to 192 ppmv.
    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using a 
variant of the SRE/Feed Approach because of concerns about a cement 
kiln's ability to replicate a given SRE. To identify the floor level we 
first evaluated the chlorine feed level in the hazardous waste for all 
sources. The best performing sources had the lowest maximum theoretical 
emissions concentration or MTEC, considering variability. We then 
applied a SRE of 90% to the best performing sources' total MTEC (i.e., 
includes chlorine contributions to emissions from all feedstreams such 
as raw material and fossil fuels) to identify the floor level. Given 
our concerns about the reproducibility of SREs of total chlorine, we 
selected a SRE of 90% because our data base shows that all sources have 
demonstrated this SRE at least once (and often several times) during a 
compliance test. The calculated floor is 110 ppmv, which considers 
emissions variability. This is an emission level that the best 
performing feed control sources could be expected to achieve in 99 of 
100 future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 93% 
of sources and would reduce total chlorine emissions by 64 tons per 
year.
    We also invite comment on an alternative approach to establish a 
floor level expressed as a hazardous waste thermal feed 
concentration.\108\ A hazardous waste thermal feed concentration is 
expressed as mass of chlorine in the hazardous waste per

[[Page 21260]]

million Btu heat input contributed by the hazardous waste. The floor 
would be based on the best five performing sources with the lowest 
thermal feed concentration of chlorine in the hazardous waste 
considering each source's most recent compliance test data. One 
advantage of this approach is that the uncertainty surrounding the 
capture (SRE) of chlorine in a kiln is removed. The calculated floor 
level would be 2.4 lbs chlorine in the hazardous waste per million Btu 
in the hazardous waste, which considers variability. For a hypothetical 
wet process cement kiln that gets 50% of its required heat input from 
hazardous waste, a hazardous waste with a chlorine concentration of 2.4 
lbs chlorine per million Btu and achieving 90% SRE equates 
approximately to a stack gas concentration of 75 ppmv. This estimated 
stack gas concentration does not include contributions to emission from 
other chlorine-containing materials such as raw materials and fossil 
fuels. The additional contribution to stack emissions of total chlorine 
in an average raw material and coal is estimated to range from less 
than 1 to 35 ppmv. Thus, for the hypothetical wet process cement kiln 
this floor level is estimated to be less than 110 ppmv, which is less 
than the current interim standard of 130 ppmv.
---------------------------------------------------------------------------

    \108\ We are also requesting comment on whether the hazardous 
waste feed concentration floor level should be the standard itself 
(i.e., no stack emission concentration standard) or as an 
alternative to the stack emission standard (e.g., sources have the 
opinion to comply with either the calculated stack emissions 
concentration or the hazardous waste feed concentration limit).
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified three potential beyond-the-floor techniques for 
control of total chlorine: (1) Use of wet scrubbers; (2) control of 
chlorine in the hazardous waste feed; and (3) control of the chlorine 
in the raw materials. For reasons discussed below, we are not proposing 
a beyond-the-floor standard for total chlorine.
    Use of Wet Scrubbers. We evaluated the use of wet scrubbers as 
beyond-the-floor control for further reduction of mercury emissions. 
Wet scrubbers are not currently being used at any hazardous waste 
burning cement kilns to capture hydrogen chloride. We evaluated a 
beyond-the-floor level of 55 ppmv. 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 $3.4 
million and would provide an incremental reduction in total chlorine 
emissions beyond the MACT floor controls of 370 tons per year. Nonair 
quality health and environmental impacts and energy effects were 
evaluated to estimate the impacts between wet scrubbing and controls 
likely to be used to meet the floor level. We estimate that this 
beyond-the-floor option would increase the amount of water usage and 
waste water generated by 1.5 billion gallon per year. The option would 
also require sources to use an additional 12 million kW-hours per year 
beyond the requirements to achieve the floor level. The costs 
associated with these impacts are accounted for in the national 
annualized compliance cost estimates. Therefore, based on these factors 
and costs of approximately $9,300 per additional ton of total chlorine 
removed, we are not proposing a beyond-the-floor standard based on wet 
scrubbing.
    Feed Control of Chlorine in the Hazardous Waste. We also evaluated 
a beyond-the-floor level of 88 ppmv, which represents a 20% reduction 
from the floor level. We chose a 20% reduction as a level that 
represents the practicable extent that additional feedrate control of 
chlorine in the hazardous waste can be used and still achieve modest 
emissions reductions. 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 $1.1 million and 
would provide an incremental reduction in total chlorine emissions 
beyond the MACT floor controls of 100 tons per year. Nonair quality 
health and environmental impacts and energy effects were also evaluated 
and are included in the compliance cost estimates. Therefore, based on 
these factors and costs of approximately $11,000 per additional ton of 
total chlorine, we are not proposing a beyond-the-floor standard based 
on feed control of chlorine in the hazardous waste.
    Feed Control of Chlorine in the Raw Materials and Auxiliary Fuels. 
Cement kilns could achieve a reduction in total chlorine emissions by 
substituting a raw material containing lower levels of chlorine for a 
primary raw material with higher levels of chlorine. We believe that 
this beyond-the-floor option would even be less cost-effective than 
either of the options discussed above because most chlorine feed to the 
kiln is in the hazardous waste. In addition, given that cement kilns 
are sited near the primary raw material supply, acquiring and 
transporting large quantities of an alternate source of raw materials 
is likely to be cost-prohibitive. Therefore, we are not proposing a 
beyond-the-floor standard based on limiting chlorine in the raw 
material feed. We also considered whether fuel switching to an 
auxiliary fuel containing a lower concentration of chlorine would be an 
appropriate control option for kilns. Given that most cement kilns 
burning hazardous waste also burn coal as a fuel, we considered 
switching to natural gas as a potential beyond-the-floor option. For 
the same reasons discussed for mercury, we judge a beyond-the-floor 
standard based on fuel switching as unwarranted.
    For the reasons discussed above, we propose not to adopt a beyond-
the-floor standard for total chlorine and propose to establish the 
emission standard for existing cement kilns at 110 ppmv.
3. What Is the Rationale for the MACT Floor for New Sources?
    Total chlorine emissions from new cement kilns are currently 
limited to 86 ppmv by Sec.  63.1204(b)(6). This standard was 
promulgated in the Interim Standards Rule (See 67 FR at 6796). The MACT 
floor for new sources for total chlorine would be 78 ppmv, which 
considers emissions variability. This is an emission level that the 
single best performing source identified with the SRE/Feed Approach 
could be expected to achieve in 99 of 100 future tests when operating 
under conditions identical to the test conditions during which the 
emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We identified similar potential beyond-the-floor techniques for 
control of total chlorine for new sources: (1) Use of wet scrubbing; 
(2) control of chlorine in the hazardous waste feed; and (3) control of 
chlorine in the raw materials and fuels.
    Use of Wet Scrubbers. We considered wet scrubbing as beyond-the-
floor control for further reductions in total chlorine emissions and 
evaluated a beyond-the-floor level of 39 ppmv. The incremental 
annualized compliance cost for a new cement kiln to meet this beyond-
the-floor level, rather than comply with the floor level, would be 
approximately $1.2 million and would provide an incremental reduction 
in total chlorine emissions of approximately 22 tons per year. Nonair 
quality health and environmental impacts and energy effects were 
evaluated and are included in the cost estimates. For these reasons and 
costs of $24,000 per ton of total chlorine removed, we are not 
proposing a beyond-the-floor standard based on wet scrubbing for new 
cement kilns.
    Feed Control of Low Volatile Metals in the Hazardous Waste. We also 
evaluated a beyond-the-floor level of 62 ppmv, which represents a 20% 
reduction from the floor level. We believe that the expense for further 
reduction in total chlorine emissions

[[Page 21261]]

based on further control of chlorine concentrations in the hazardous 
waste is not warranted given the costs, nonair quality health and 
environmental impacts, and energy effects.
    Feed Control of Chlorine in the Raw Materials and Auxiliary Fuels. 
Cement kilns could achieve a reduction in total chlorine emissions by 
substituting a raw material containing lower levels of chlorine for a 
primary raw material with a higher level. For a new source at an 
existing cement plant, we believe that this beyond-the-floor option 
would not be cost-effective due to the costs of transporting large 
quantities of an alternate source of raw materials to the cement plant. 
Given that the plant site already exists and sited near the source of 
raw material, replacing the raw materials at the plant site with lower 
chlorine-containing materials would be the source's only option. For a 
cement kiln constructed at a new greenfield site, we are not aware of 
any information and data from a source that has undertaken or is 
currently located at a site whose raw materials are inherently lower in 
chlorine that would consistently achieve reduced total chlorine 
emissions. Further, we are uncertain as to what beyond-the-floor 
standard would be achievable using a lower, if it exists, chlorine-
containing raw material. Although we are doubtful that selecting a new 
plant site based on the content of chlorine in the raw material is a 
realistic beyond-the-floor option considering the numerous additional 
factors that go into such a decision, we solicit comment on whether and 
what level of a beyond-the-floor standard based on controlling the 
level of chlorine in the raw materials is appropriate.
    We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of chlorine would be an appropriate 
control option for sources. Given that most cement kilns burning 
hazardous waste also burn coal as a fuel, we considered switching to 
natural gas as a potential beyond-the-floor option. For the same 
reasons discussed for mercury, we judge a beyond-the-floor standard 
based on fuel switching as unwarranted.
    Therefore, we are proposing a total chlorine standard of 78 ppmv 
for new cement kilns.

G. What Are the Standards for Hydrocarbons and Carbon Monoxide?

    Hydrocarbon and carbon monoxide standards are surrogates to control 
emissions of organic hazardous air pollutants for existing and new 
cement kilns. For cement kilns without bypass or midkiln sampling 
systems, the standard for existing sources limit hydrocarbon or carbon 
monoxide concentrations to 20 ppmv or 100 ppmv, respectively. The 
standards for new sources limit (1) hydrocarbons to 20 ppmv; or (2) 
carbon monoxide to 100 ppmv. New, greenfield kilns\109\, that elect to 
comply with the 100 ppmv carbon monoxide standard, however, must also 
comply with a 50 ppmv 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. However, continuous hydrocarbon 
monitoring following the performance test is not required.
---------------------------------------------------------------------------

    \109\ 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 is not 
classified as a greenfield cement kiln, and is subject to the same 
carbon monoxide and hydrocarbon standards as an existing cement 
kiln.
---------------------------------------------------------------------------

    For cement kilns with bypass or midkiln sampling systems, existing 
cement kilns are required to comply with either a carbon monoxide 
standard of 100 ppmv or a hydrocarbon standard of 10 ppmv. Both 
standards apply to combustion gas sampled in the bypass or a midkiln 
sampling port that samples representative kiln gas. See Sec. Sec.  
63.1204(a)(5) and (b)(5). The rationale for these decisions are 
discussed in the September 1999 final rule (64 FR at 52885). We view 
the standards for hydrocarbons and carbon monoxide as unaffected by the 
Court's vacature of the challenged regulations in its decision of July 
24, 2001. We therefore are not proposing these standards for cement 
kilns, but rather are mentioning them here for the reader's 
convenience.

H. What Are the Standards for Destruction and Removal Efficiency?

    The destruction and removal efficiency (DRE) standard is a 
surrogate to control emissions of organic hazardous air pollutants 
other than dioxin/furans. The standard for existing and new lightweight 
aggregate kilns requires 99.99% DRE for each principal organic 
hazardous constituent, except that 99.9999% DRE is required if 
specified dioxin-listed hazardous wastes are burned. See Sec. Sec.  
63.1204(c). The rationale for these decisions are discussed in the 
September 1999 final rule (64 FR at 52890). We view the standards for 
DRE as unaffected by the Court's vacature of the challenged regulations 
in its decision of July 24, 2001. We therefore are not proposing these 
standards for cement kilns, but rather are mentioning them here for the 
reader's convenience.

IX. How Did EPA Determine the Proposed Emission Standards for Hazardous 
Waste Burning Lightweight Aggregate Kilns?

    In this section, the basis for the proposed emission standards is 
discussed. See proposed Sec.  63.1221. The proposed emission limits 
apply to the stack gases from lightweight aggregate kilns that burn 
hazardous waste and are summarized in the table below:

   Proposed Standards for Existing and New Lightweight Aggregate Kilns
------------------------------------------------------------------------
                                         Emission standard \1\
 Hazardous air pollutant or  -------------------------------------------
          surrogate             Existing sources         New sources
------------------------------------------------------------------------
Dioxin and furan............  0.40 ng TEQ/dscm....  0.40 ng TEQ/dscm.
Mercury \2\.................  67 [mu]g/dscm.......  67 [mu]g/dscm.
Particulate Matter..........  57 mg/dscm (0.025 gr/ 23 mg/dscm (0.0099
                               dscf).                gr/dscf).
Semivolatile metals \3\.....  3.1 x 10-4 lb/MMBtu   2.4 x 10-5 lb/MMBtu
                               and 250 [mu]g/dscm.   and 43 [mu]g/dscm.
Low volatile metals \3\.....  9.5 x 10-5 lb/MMBtu   3.2 x 10-5 lb/MMBtu
                               and 110 [mu]g/dscm.   and 110 [mu]g/dscm.
Hydrogen chloride and         600 ppmv............  600 ppmv.
 chlorine gas \4\.
Hydrocarbons 5, 6...........  20 ppmv (or 100 ppmv  20 ppmv (or 100 ppmv
                               carbon monoxide).     carbon monoxide).

[[Page 21262]]

 
Destruction and removal       For existing and new sources, 99.99% for
 efficiency.                   each principal organic hazardous
                               constituent (POHC). For sources burning
                               hazardous wastes F020, F021, F022, F023,
                               F026, or F027, however, 99.9999% for each
                               POHC.
------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen, dry basis.
\2\ Mercury standard is an annual limit.
\3\ Standards are expressed as mass of pollutant emissions contributed
  by hazardous waste per million British thermal unit contributed by the
  hazardous waste.
\4\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\5\ Sources that elect to comply with the carbon monoxide standard must
  demonstrate compliance with the hydrocarbon standard during the
  comprehensive performance test.
\6\ Hourly rolling average. Hydrocarbons reported as propane.

A. What Are the Proposed Standards for Dioxin and Furan?

    We are proposing to establish standards for existing and new 
lightweight aggregate kilns that limit emissions of dioxin and furans 
to 0.40 ng TEQ/dscm.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Dioxin and furan emissions for existing lightweight aggregate kilns 
are currently limited by Sec.  63.1205(a)(1) to 0.20 ng TEQ/dscm or 
rapid quench of the flue gas at the exit of the kiln to less than 
400[deg]F. This standard was promulgated in the Interim Standards Rule 
(See 67 FR at 6797).
    Since promulgation of the September 1999 final rule, we have 
obtained additional dioxin/furan emissions data. We now have compliance 
test emissions data for all lightweight aggregate kilns that burn 
hazardous waste. The compliance test dioxin/furan emissions in our 
database range from approximately 0.9 to 58 ng TEQ/dscm.
    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 (400-
750[deg]F) may be problematic for some of these sources. Some of these 
sources have extensive (long) duct-work between the kiln exit and the 
inlet to the control device. For these sources, quenching the gases at 
the kiln exit to a low enough temperature to limit dioxin/furan 
formation may conflict with the source's ability to avoid acid gas dew 
point related problems in the long duct-work and control device. As a 
result, some sources quench the kiln exit gases to a temperature that 
is in the optimum temperature range for surface-catalyzed dioxin/furan 
formation. Available compliance test emissions data indicate that inlet 
temperatures to the control device range from 435-450[deg]F. This means 
that temperatures in the duct-work are higher and well within the range 
of optimum dioxin/furan formation.
    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
Emissions Approach described in Part Two, Section VI above. The 
calculated floor is 14 ng TEQ/dscm, which considers emissions 
variability. However, the current interim emission standard--0.20 ng 
TEQ/dscm or rapid quench of the flue gas at the exit of the kiln to 
less than 400[deg]F--is a regulatory limit that is relevant in 
identifying the floor level because it fixes a level of performance for 
the source category. We estimate that sources achieving the ``rapid 
quench of the flue gas at the exit of the kiln to less than 400[deg]F'' 
part of the current standard can emit up to 6.1 ng TEQ/dscm. Given that 
all sources are achieving the interim standard and that the interim 
standard is judged as more stringent than the calculated MACT floor, 
the dioxin/furan floor level can be no less stringent than the current 
regulatory limit.\110\ We are, therefore, proposing the dioxin/furan 
floor level as the current emission standard of 0.20 ng TEQ/dscm or 
rapid quench of the flue gas at the exit of the kiln to less than 
400[deg]F. This emission level is being achieved by all sources because 
it is the interim standard. In addition, there are no emissions 
reductions for existing lightweight aggregate kilns to comply with the 
floor level.
---------------------------------------------------------------------------

    \110\ Even though all sources have recently demonstrated 
compliance with the interim standards, the dioxin/furan data in our 
data base preceded the compliance demonstration. This explains why 
we have emissions data that are higher than the interim standard.
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated activated carbon injection as beyond-the-floor control 
for further reduction of dioxin/furan emissions. Activated carbon has 
been demonstrated for controlling dioxin/furans in various combustion 
applications; however, no lightweight aggregate kiln that burns 
hazardous waste uses activated carbon injection. We evaluated a beyond-
the-floor level of 0.40 ng TEQ/dscm, which represents a level that is 
considered routinely achievable using activated carbon injection. In 
addition, we assumed for costing purposes that lightweight aggregate 
kilns needing activated carbon injection to achieve the beyond-the-
floor level would install the activated carbon injection system after 
the existing particulate matter control device and add a new, smaller 
baghouse to remove the injected carbon with the adsorbed dioxin/furans. 
We chose this costing approach to address potential concerns that 
injected carbon may interfere with lightweight aggregate dust use 
practices.
    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 $1.8 million and would 
provide an incremental reduction in dioxin/furan emissions beyond the 
MACT floor controls of 1.9 grams TEQ per year. Nonair quality health 
and environmental impacts and energy effects were evaluated to estimate 
the nonair quality health and environmental impacts between activated 
carbon injection and controls likely to be used to meet the floor 
level. We estimate that this beyond-the-floor option would increase the 
amount of solid waste generated by 550 tons per year and would require 
sources to use an additional 1 million kW-hours per year beyond the 
requirements to achieve the floor level. The costs associated with 
these impacts are accounted for in the national compliance cost 
estimates.
    Therefore, based on these factors and costs of approximately $0.95 
million per additional gram of dioxin/furan TEQ

[[Page 21263]]

removed, we are proposing a beyond-the-floor standard of 0.40 ng TEQ/
dscm for existing lightweight aggregate kilns. We judge that the cost 
to achieve this beyond-the-floor level is warranted given our special 
concern about dioxin/furan. Dioxin/furan 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 
our dioxin/furan for priority MACT control in CAA section 112(c)(6). 
See S. Rep. No. 128, 101st Cong. 1st Sess. at 154-155. In addition, we 
note that a beyond-the-floor standard of 0.40 ng TEQ/dscm is consistent 
with historically controlled levels under MACT for hazardous waste 
incinerators and cement kilns, and Portland cement plants. See 
Sec. Sec.  63.1203(a)(1), 63.1204(a)(1), and 63.1343(d)(3). Also, EPA 
has determined previously in the 1999 Hazardous Waste Combustor MACT 
final rule that dioxin/furan in the range of 0.40 ng TEQ/dscm or less 
are necessary for the MACT standards to be considered generally 
protective of human health under RCRA (using the 1985 cancer slope 
factor), thereby eliminating the need for separate RCRA standards under 
the authority of RCRA section 3005(c)(3) and 40 CFR 270.10(k). Finally, 
we note that this decision is not inconsistent with EPA's decision not 
to promulgate beyond-the-floor standards for dioxin/furan for hazardous 
waste burning lightweight aggregate kilns, cement kilns, and 
incinerators at cost-effectiveness values in the range of $530,000 to 
$827,000 per additional gram of dioxin/furan TEQ removed. See 64 FR at 
52892, 52876, and 52961. In those cases, EPA determined that 
controlling dioxin/furan emissions from a level of 0.40 ng TEQ/dscm to 
a beyond-the-floor level of 0.20 ng TEQ/dscm was not warranted because 
dioxin/furan levels below 0.40 ng TEQ/dscm are generally considered to 
be below the level of health risk concern.
    We specifically request comment on whether this beyond-the-floor 
standard is warranted.
3. What Is the Rationale for the MACT Floor for New Sources?
    Dioxin and furan emissions for new lightweight aggregate kilns are 
currently limited by Sec.  63.1205(b)(1) to 0.20 ng TEQ/dscm or rapid 
quench of the flue gas at the exit of the kiln to less than 400[deg]F. 
This standard was promulgated in the Interim Standards Rule (See 67 FR 
at 6797).
    The calculated MACT floor for new sources would be 1.3 ng TEQ/dscm, 
which considers emissions variability, or rapid quench of the flue gas 
at the exit of the kiln to less than 400[deg]F. This is an emission 
level that the single best performing source identified by the 
Emissions Approach. However, we are concerned that the calculated floor 
level of 1.3 ng TEQ/dscm is not duplicable by all sources using 
temperature control because we estimate that sources rapidly quenching 
the flue gas at the exit of the kiln to less than 400[deg]F can emit up 
to 6.1 ng TEQ/dscm. Therefore, we are proposing the floor as the 
current emission standard of 0.20 ng TEQ/dscm or rapid quench of the 
flue gas at the exit of the kiln to less than 400[deg]F.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated activated carbon injection as beyond-the-floor control 
for further reduction of dioxin/furan emissions, and considered a 
beyond-the-floor level of 0.40 ng TEQ/dscm, which represents a level 
that is considered routinely achievable with activated carbon 
injection. In addition, we assumed for costing purposes that a new 
lightweight aggregate kiln will install the activated carbon injection 
system after the existing particulate matter control device and add a 
new, smaller baghouse to remove the injected carbon with the adsorbed 
dioxin/furan. The incremental annualized compliance cost for a new 
source to meet this beyond-the-floor level, rather than comply with the 
floor level, would be approximately $0.26 million and would provide an 
incremental reduction in dioxin/furan emissions of 0.37 grams per year. 
Nonair quality health, environmental impacts, and energy effects are 
accounted for in the cost estimates. Therefore, based on these factors 
and cost of $0.71 million per gram TEQ removed, we are proposing a 
beyond-the-floor standard based on activated carbon injection. We 
believe that the cost to achieve this beyond-the-floor level is 
warranted given our special concern about dioxin/furan. Dioxin/furan 
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. In addition, as discussed above, we note that 
the beyond-the-floor emission level of 0.40 ng TEQ/dscm is consistent 
with historically controlled levels under MACT for hazardous waste 
incinerators and cement kilns, and Portland cement plants. See 
Sec. Sec.  63.1203(a)(1), 63.1204(a)(1), and 63.1343(d)(3). EPA has 
determined previously in the 1999 Hazardous Waste Combustor MACT final 
rule that dioxin/furan in the range of 0.40 ng TEQ/dscm or less are 
necessary for the MACT standards to be considered generally protective 
of human health under RCRA, thereby eliminating the need for separate 
RCRA standards.
    We specifically request comment on whether this beyond-the-floor 
standard is warranted.

B. What Are the Proposed Standards for Mercury?

    We are proposing to establish standards for existing and new 
lightweight aggregate kilns that limit emissions of mercury to 67 
[mu]g/dscm.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Mercury emissions for existing lightweight aggregate kilns are 
currently limited to 120 [mu]g/dscm by Sec.  63.1205(a)(2). Existing 
lightweight aggregate kilns have the option to comply with an 
alternative mercury standard that limits the hazardous waste maximum 
theoretical emissions concentration (MTEC) of mercury to 120 [mu]g/
dscm.\111\ This standard was promulgated in the Interim Standards Rule 
(See 67 FR at 6797). One lightweight aggregate facility with two kilns 
uses a venturi scrubber to remove mercury from the flue gas stream and 
the remaining sources limit the feed concentration of mercury in the 
hazardous waste to control emissions.
---------------------------------------------------------------------------

    \111\ MTEC is a term 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 
units of [mu]g/dscm.
---------------------------------------------------------------------------

    We have compliance test emissions data for only one source; 
however, we have normal emissions data for all sources. For most 
sources, we have normal emissions data from more than one test 
campaign. We used these emissions data to represent the average 
emissions from a source even though we do not know whether the 
emissions represent the high end, low end, or close to the average 
emissions. The normal mercury stack emissions range from less than 1 to 
47 [mu]g/dscm, while the highest compliance test emissions data is 
1,050 [mu]g/dscm. These emissions are expressed as mass of mercury 
(from all feedstocks) per unit volume of stack gas.
    To identify the MACT floor, we evaluated all normal emissions data 
using the SRE/Feed Approach. We considered normal stack emissions data 
from all test campaigns.\112\ For example,

[[Page 21264]]

one source in our data base has normal emissions data for three 
different testing campaigns: 1992, 1995, and 1999. Under this approach 
we considered the emissions data from the three separate years or 
campaigns. As explained earlier, we believe this approach better 
captures the range of average emissions for a source than only 
considering the most recent normal emissions. In addition, for sources 
without control equipment to capture mercury, we assumed the sources 
achieved a SRE of zero. The effect of this assumption is that the 
sources (without control equipment for mercury) with the lower mercury 
concentrations in the hazardous waste were identified as the better 
performing sources.
---------------------------------------------------------------------------

    \112\ Given that the majority of feedrate and emissions data for 
mercury is normal, we do not believe it is appropriate to establish 
a hazardous waste thermal emissions-based standard. We prefer to 
establish emission standards under the hazardous waste thermal 
emissions format using compliance test data because the metals 
feedrate information from compliance tests that we use to apportion 
emissions to calculate emissions attributable to hazardous waste are 
more reliable than feedrate data measured during testing under 
normal, typical operations.
---------------------------------------------------------------------------

    The calculated floor is 67 [mu]g/dscm, which considers emissions 
variability, based on a hazardous waste maximum theoretical emissions 
concentration (MTEC) of 42 [mu]g/dscm. This is an emission level that 
the average of the best performing sources could be expected to achieve 
in 99 of 100 future tests when operating under operating conditions 
identical to the compliance test conditions during which the emissions 
data were obtained. We estimate that this emission level is being 
achieved by 57% of sources and would reduce mercury emissions by 8 
pounds per year. If we were to adopt such a floor level, we are 
proposing that sources comply with the limit on an annual basis because 
it is based on normal emissions data. Under this approach, compliance 
would not be based on the use of a total mercury continuous emissions 
monitoring system because these monitors have not been adequately 
demonstrated as a reliable compliance assurance tool at all types of 
incinerator sources. Instead, a source would maintain compliance with 
the mercury standard by establishing and complying with short-term 
limits on operating parameters for pollution control equipment and 
annual limits on maximum total mercury feedrate in all feedstreams.
    In the September 1999 final rule, we acknowledged that a 
lightweight aggregate kiln using properly designed and operated MACT 
control technologies, including controlling the levels of metals in the 
hazardous waste, may not be capable of achieving a given emission 
standard because of process raw material contributions that might cause 
an exceedance of the emission standard. To address this concern, we 
promulgated a provision that allows sources to petition for alternative 
standards provided they submit site-specific information that shows raw 
material hazardous air pollutant contributions to the emissions prevent 
the source from complying with the emission standard even though the 
kiln is using MACT control. See Sec.  63.1206(b)(9).
    Today's proposed floor of 67 [mu]g/dscm, which was based on a 
hazardous waste MTEC of 42 [mu]g/dscm, may likewise necessitate such an 
alternative because contributions of mercury in the raw materials and 
fossil fuels at some sources may cause an exceedance of the emission 
standard. The Agency intends to retain a source's ability to comply 
with an alternative standard, and we request comment on two approaches 
to accomplish this. The first approach would be to structure the 
alternative standard similar to the petitioning process used under 
Sec.  63.1206(b)(9). In the case of mercury for an existing lightweight 
aggregate kiln, MACT would be defined as a hazardous waste feedrate 
corresponding to an MTEC of 42 [mu]g/dscm. If we were to adopt this 
approach, we would require sources, upon approval of the petition by 
the Administrator, to comply with this hazardous waste MTEC on an 
annual basis because it is based on normal emissions data. Under the 
second approach, we would structure the alternative standard similar to 
the framework used for the alternative interim standards for mercury 
under Sec.  63.1206(b)(15). The operating requirement would be an 
annual MTEC not to exceed 42 [mu]g/dscm. We also request comment on 
whether there are other approaches that would more appropriately 
provide relief to sources that cannot achieve a total stack gas 
concentration standard because of emissions attributable to raw 
material and nonhazardous waste fuels.
    In comments submitted to EPA in 1997, Solite Corporation (Solite), 
owner and operator of five \113\ of the seven lightweight aggregate 
kilns, stated that the normal emissions data in our data base are 
unrepresentative of average emissions of mercury because the normal 
range of mercury concentrations in the hazardous waste burned during 
the compliance and trial burn tests was not captured during the tests. 
In their 1997 comments, Solite provided information on actual mercury 
concentrations in the hazardous waste burn tanks over a year and a 
quarter period. The information showed that 87% of the burn tanks 
contained mercury at concentrations below the facility's detection 
limit of 2 ppm. Additional analyses of a limited number of these 
samples conducted at an off-site lab showed that the majority of 
samples were actually less than 0.2 ppm.\114\
---------------------------------------------------------------------------

    \113\ Solite Corporation has four kilns at its Cascade facility 
and three kilns at its Arvonia facility. However, only three kilns 
and two kilns, respectively, can be fired with hazardous waste at 
any one time. For purposes of today's proposal, Solite Corporation 
is assumed to operate a total of five kilns.
    \114\ A hazardous waste with a mercury concentration of 2 ppm 
equates approximately to a mercury emissions level of 200-250 [mu]g/
dscm, and a source firing a hazardous waste with a mercury 
concentration of 0.2 ppm approximately equates to 20-25 [mu]g/dscm. 
The existing standard of 120 [mu]g/dscm allows a source to burn a 
hazardous waste with a mercury concentration of approximately 1 ppm.
---------------------------------------------------------------------------

    We examined the test reports of the five best performing sources 
that are the basis of today's proposed floor level to determine the 
concentration level of mercury in the hazardous wastes. The hazardous 
waste burned by the best performing sources during the tests that 
generated the normal emissions data had mercury concentrations that 
ranged from 0.02 to 0.2 ppm.\115\ Even though the concentrations of 
mercury in the hazardous waste seem low, we cannot judge how these snap 
shot concentrations compare to long-term normal concentrations because 
the majority of the burn tank concentration data submitted by Solite 
are nondetect measurements at a higher detection limit.
---------------------------------------------------------------------------

    \115\ These mercury concentrations were analyzed by an off-site 
lab that had equipment capable of detecting mercury at lower 
concentrations. Sixteen of the 27 measurements of the best 
performers were reported as non-detects.
---------------------------------------------------------------------------

    Solite informed us in July 2003 that they are in the process of 
upgrading the analysis equipment at their on-site laboratory. Once 
completed, Solite expects to be capable of detecting mercury in the 
hazardous waste at concentrations of 0.2 ppm. Solite also indicated 
that they intend to assemble and submit to EPA several months of burn 
tank concentration data analyzed with the new equipment. We will add 
these data to the docket of today's proposal once available. As we 
discussed for cement kilns for mercury, we are requesting comment on 
approaches to establish a hazardous waste feed concentration standard 
based on long-term feed concentrations of mercury in the hazardous 
waste. Likewise, we invite comments on establishing a mercury feed

[[Page 21265]]

concentration standard for lightweight aggregate kilns.
    We also invite comment on whether we should judge an annual limit 
of 67 [mu]g/dscm as less stringent than either the current emission 
standard of 120 [mu]g/dscm or the hazardous waste MTEC of mercury of 
120 [mu]g/dscm for lightweight aggregate kilns (so as to avoid any 
backsliding from a current level of performance achieved by all 
sources, and hence, the level of minimal stringency at which EPA could 
calculate the MACT floor). In order to comply with the current emission 
standard, generally a source must conduct manual stack sampling to 
demonstrate compliance with the mercury emission standard and then 
establish a maximum mercury feedrate limit based on operations during 
the performance test. Following the performance test, the source 
complies with a limit on the maximum total mercury feedrate in all 
feedstreams on a 12-hour rolling average (not an annual average). 
Alternatively, a source can elect to comply with a hazardous waste MTEC 
of mercury of 120 [mu]g/dscm that would require the source to limit the 
mercury feedrate in the hazardous waste on a 12-hour rolling average. 
The floor level of 67 [mu]g/dscm proposed today would allow a source to 
feed more variable mercury-containing feedstreams (e.g., a hazardous 
waste with a mercury MTEC greater than 120 [mu]g/dscm) than the current 
12-hour rolling average because today's proposed floor level is an 
annual limit. For example, the concentration of mercury in the 
hazardous waste exceeded a hazardous waste MTEC of 120 [mu]g/dscm in a 
minimum of 13% of the burn tanks based on the data submitted by Solite 
in their 1997 comments (discussed above). As mentioned above, Solite 
intends to submit several months of burn tank concentration data using 
upgraded analysis equipment at their on-site laboratory that we will 
consider when comparing the relative stringency of an annual limit of 
67 [mu]g/dscm and a short-term limit of 120 [mu]g/dscm.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified three potential beyond-the-floor techniques for 
control of mercury: (1) Activated carbon injection; (2) control of 
mercury in the hazardous waste feed; and (3) control of mercury in the 
raw materials and auxiliary fuels. For reasons discussed below, we are 
not proposing a beyond-the-floor standard for mercury.
    Use of Activated Carbon Injection. We evaluated activated carbon 
injection as beyond-the-floor control for further reduction of mercury 
emissions. Activated carbon has been demonstrated for controlling 
mercury in several combustion applications; however, currently no 
lightweight aggregate kiln that burns hazardous waste uses activated 
carbon injection. Given this lack of experience using activated carbon 
injection, we made a conservative assumption that the use of activated 
carbon injection will provide 70% mercury control and evaluated a 
beyond-the-floor level of 20 [mu]g/dscm. In addition, for costing 
purposes we assumed that sources needing activated carbon injection to 
achieve the beyond-the-floor level would install the activated carbon 
injection system after the existing baghouse and add a new, smaller 
baghouse to remove the injected carbon with the adsorbed mercury. We 
chose this costing approach to address potential concerns that injected 
carbon may interfere with lightweight aggregate kiln dust use 
practices.
    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 $1.1 million and would 
provide an incremental reduction in mercury emissions beyond the MACT 
floor controls of 11 pounds per year. Nonair quality health and 
environmental impacts and energy effects were evaluated to estimate the 
impacts between activated carbon injection and controls likely to be 
used to meet the floor level. We estimate that this beyond-the-floor 
option would increase the amount of solid waste generated by 270 tons 
per year and would require sources to use an additional 1.2 million kW-
hours per year beyond the requirements to achieve the floor level. The 
costs associated with these impacts are accounted for in the national 
annualized compliance cost estimates. Therefore, based on these factors 
and costs of approximately $209 million per additional ton of mercury 
removed, we are not proposing a beyond-the-floor standard based on 
activated carbon injection.
    Feed Control of Mercury in the Hazardous Waste. We also evaluated a 
beyond-the-floor level of 54 [mu]g/dscm, which represents a 20% 
reduction from the floor level. We chose a 20% reduction as a level 
representing the practicable extent that additional feedrate control of 
mercury in hazardous waste (beyond feedrate control that may be 
necessary to achieve the floor level) can be used and still achieve 
modest emissions reductions.\116\ 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 $0.3 million and would provide an incremental reduction 
in mercury emissions beyond the MACT floor controls of 3 pounds per 
year. Nonair quality health and environmental impacts and energy 
effects were also evaluated. Therefore, based on these factors and 
costs of approximately $229 million per additional ton of mercury 
removed, we are not proposing a beyond-the-floor standard based on feed 
control of mercury in the hazardous waste.
---------------------------------------------------------------------------

    \116\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume V: Emission Estimates and Engineering 
Costs'', March 2004, Chapter 4.
---------------------------------------------------------------------------

    Feed Control of Mercury in the Raw Materials and Auxiliary Fuels. 
Lightweight aggregate kilns could achieve a reduction in mercury 
emissions by substituting a raw material containing a lower level of 
mercury for a primary raw material with a higher level. We believe that 
this beyond-the-floor option would be even less cost-effective than 
either of the options discussed above, however. Given that sources are 
sited near the supply of the primary raw material, transporting large 
quantities of an alternate source of raw materials, even if available, 
is likely to be cost-prohibitive, especially considering the small 
expected emissions reductions that would result.
    We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of mercury would be an appropriate 
control option for sources. Two facilities typically burn hazardous 
waste at a fuel replacement rate of 100%, while one facility has burned 
a combination of fuel oil and natural gas in addition to the hazardous 
waste. We considered switching only to natural gas as the auxiliary 
fuel as a potential beyond-the-floor option. We do not believe that 
switching to natural gas is a viable control option for the same 
reasons discussed above for cement kilns.
    For the reasons discussed above, we propose to establish the 
emission standard for existing lightweight aggregate kilns at 67 [mu]g/
dscm. If we were to adopt such a standard, we are proposing that 
sources comply with the standard on an annual basis because it is based 
on normal emissions data.

[[Page 21266]]

3. What Is the Rationale for the MACT Floor for New Sources?
    Mercury emissions from new lightweight aggregate kilns are 
currently limited to 120 [mu]g/dscm by Sec.  63.1205(b)(2). This 
standard was promulgated in the Interim Standards Rule (see 67 FR at 
6797).
    The MACT floor for new sources for mercury would be 67 [mu]g/dscm, 
which considers emissions variability. This is an emission level that 
the single best performing source identified with the SRE/Feed Approach 
could be expected to achieve in 99 of 100 future tests when operating 
under operating conditions identical to the compliance test conditions 
during which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We identified the same three potential beyond-the-floor techniques 
for control of mercury: (1) Use of activated carbon; (2) control of 
mercury in the hazardous waste feed; and (3) control of the mercury in 
the raw materials and auxiliary fuels.
    Use of Activated Carbon Injection. We evaluated activated carbon 
injection as beyond-the-floor control for further reduction of mercury 
emissions. We made a conservative assumption that the use of activated 
carbon injection will provide 70% mercury control and evaluated a 
beyond-the-floor level of 20 [mu]g/dscm. The incremental annualized 
compliance cost for a new lightweight aggregate kiln with average gas 
flow rate to meet this beyond-the-floor level, rather than comply with 
the floor level, would be approximately $0.26 million and would provide 
an incremental reduction in mercury emissions of approximately 42 
pounds per year. Nonair quality health and environmental impacts and 
energy effects are accounted for in the national annualized compliance 
cost estimates. Therefore, based on these factors and costs of $12 
million per ton of mercury removed, we are not proposing a beyond-the-
floor standard based on activated carbon injection for new sources.
    Feed Control of Mercury in the Hazardous Waste. We also believe 
that the expense for further reduction in mercury emissions based on 
further control of mercury concentrations in the hazardous waste is not 
warranted. A beyond-the-floor level of 54 [mu]g/dscm, which represents 
a 20% reduction from the floor level, would result in little additional 
mercury reductions. For similar reasons discussed above for existing 
sources, we conclude that a beyond-the-floor standard based on 
controlling the mercury in the hazardous waste feed would not be 
justified because of the costs coupled with estimated emission 
reductions.
    Feed Control of Mercury in the Raw Materials and Auxiliary Fuels. 
Lightweight aggregate kilns could achieve a reduction in mercury 
emissions by substituting a raw material containing lower levels of 
mercury for a primary raw material with a higher level. For a new 
source at an existing lightweight aggregate plant, we believe that this 
beyond-the-floor option would not be cost-effective due to the costs of 
transporting large quantities of an alternate source of raw materials 
to the facility. Given that the plant site already exists and sited 
near the source of raw material, replacing the raw materials at the 
plant site with lower mercury-containing materials would be the 
source's only option. For a new lightweight aggregate kiln constructed 
at a new site--a greenfield site \117\--we are not aware of any 
information and data from a source that has undertaken or is currently 
located at a site whose raw materials are low in mercury which would 
consistently decrease mercury emissions. Further, we are uncertain as 
to what beyond-the-floor standard would be achievable using a lower, if 
it exists, mercury-containing raw material. Although we are doubtful 
that selecting a new plant site based on the content of metals in the 
raw material is a realistic beyond-the-floor option considering the 
numerous additional factors that go into such a decision, we solicit 
comment on whether and what level of a beyond-the-floor standard based 
on controlling the level of mercury in the raw materials is 
appropriate.
---------------------------------------------------------------------------

    \117\ A greenfield source is a kiln constructed at a site where 
no lightweight aggregate kiln previously existed; however, a newly 
constructed or reconstructed kiln at an existing site would not be 
considered as a greenfield kiln.
---------------------------------------------------------------------------

    We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of mercury would be an appropriate 
control option for sources. We considered using natural gas in lieu of 
a fuel containing higher concentrations of mercury as a potential 
beyond-the-floor option. As discussed for existing sources, we are 
concerned about the availability of the natural gas infrastructure in 
all regions of the United States and believe that using natural gas 
would not be a viable control option for all new sources. Therefore, we 
are not proposing a beyond-the-floor standard based on limiting mercury 
in the raw material feed and auxiliary fuels.
    Therefore, we propose a mercury standard of 67 [mu]g/dscm for new 
sources. If we were to adopt such a standard, we are proposing that 
sources comply with the standard on an annual basis because it is based 
on normal emissions data.

C. What Are the Proposed Standards for Particulate Matter?

    We are proposing to establish standards for existing and new 
lightweight aggregate kilns that limit emissions of particulate matter 
to 0.025 and 0.0099 gr/dscf, respectively. This standard would control 
unenumerated HAP metals in hazardous waste, and all non-Hg HAP metals 
in the raw material and fossil fuel inputs to the kiln.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Particulate matter emissions for existing lightweight aggregate 
kilns are currently limited to 0.025 gr/dscf (57 mg/dscm) by Sec.  
63.1205(a)(7). This standard was promulgated in the Interim Standards 
Rule (See 67 FR at 6797). The particulate matter standard is a 
surrogate control for the non-mercury metal HAP. All lightweight 
aggregate kilns control particulate matter with baghouses.
    We have compliance test emissions data for all lightweight 
aggregate kiln sources. For most sources, we have compliance test 
emissions data from more than one compliance test campaign. Our 
database of particulate matter stack emissions range from 0.001 to 
0.042 gr/dscf.
    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
APCD Approach. The calculated floor is 0.029 gr/dscf, which considers 
emissions variability. This is an emission level that the average of 
the best performing sources could be expected to achieve in 99 of 100 
future tests when operating under operating conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. The calculated floor level of 0.029 gr/dscf is less stringent 
than the interim standard of 0.025 gr/dscf, which is a regulatory limit 
relevant in identifying the floor level (so as to avoid any backsliding 
from a current level of performance achieved by all lightweight 
aggregate kilns, and hence, the level of minimal stringency at which 
EPA could calculate the MACT floor). Therefore, we are proposing the 
floor level as the current emission standard of 0.025 gr/dscf. This 
emission level is currently being achieved by all sources.

[[Page 21267]]

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated improved particulate matter control to achieve a 
beyond-the-floor standard of 29 mg/dscm (0.013 gr/dscf). 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 $0.32 million and would provide an 
incremental reduction in particulate matter emissions beyond the MACT 
floor controls of 8.6 tons per year. Nonair quality health and 
environmental impacts and energy effects were evaluated to estimate the 
impacts between further improvements to control particulate matter and 
controls likely to be used to meet the floor level. We estimate that 
this beyond-the-floor option would increase the amount of solid waste 
generated by 9 tons per year beyond the requirements to achieve the 
floor level. Therefore, based on these factors and costs of 
approximately $36,600 per additional ton of particulate matter removed, 
we are not proposing a beyond-the-floor standard based on improved 
particulate matter control.
3. What Is the Rationale for the MACT Floor for New Sources?
    Particulate matter emissions from new lightweight aggregate kilns 
are currently limited to 0.025 gr/dscf by Sec.  63.1205(b)(7). This 
standard was promulgated in the Interim Standards Rule (See 67 FR at 
6797, February 13, 2002).
    The MACT floor for new sources for particulate matter would be 23 
mg/dscm (0.0099 gr/dscf), which considers emissions variability. This 
is an emission level that the single best performing source identified 
with the APCD Approach could be expected to achieve in 99 of 100 future 
tests when operating under operating conditions identical to the 
compliance test conditions during which the emissions data were 
obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated improved particulate matter control to achieve a 
beyond-the-floor standard. We evaluated a beyond-the-floor level of 12 
mg/dscm (0.005 gr/dscf). The incremental annualized compliance cost for 
a new lightweight aggregate kiln with an average gas flow rate to meet 
this beyond-the-floor level, rather than comply with the floor level, 
would be approximately $91,400 million and would provide an incremental 
reduction in particulate matter emissions of approximately 2 tons per 
year. Nonair quality health and environmental impacts and energy 
effects were also evaluated and are included in the cost estimates. 
Therefore, based on these factors and costs of approximately $45,600 
per additional ton of particulate removed, we are not proposing a 
beyond-the-floor standard based on improved particulate matter control 
for new lightweight aggregate kilns. Therefore, we propose a 
particulate matter standard of 2.3 mg/dscm (0.0099 gr/dscf) for new 
sources.

D. What Are the Proposed Standards for Semivolatile Metals?

    We are proposing to establish standards for existing lightweight 
aggregate kilns that limit emissions of semivolatile metals (cadmium 
and lead, combined) to 3.1 x 10-4 lbs semivolatile metals 
emissions attributable to the hazardous waste per million Btu heat 
input of the hazardous waste and 250 [mu]g/dscm. The proposed standard 
for new sources is 2.4 x 10-5 lbs semivolatile metals 
emissions attributable to the hazardous waste per million Btu heat 
input of the hazardous waste and 43 [mu]g/dscm.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Semivolatile metals emissions from existing lightweight aggregate 
kilns are currently limited to 250 [mu]g/dscm by Sec.  63.1205(a)(3). 
This standard was promulgated in the Interim Standards Rule (See 67 FR 
at 6797). Lightweight aggregate kilns control emissions of semivolatile 
metals with baghouses and/or by controlling the feed concentration of 
semivolatile metals in the hazardous waste.
    We have compliance test emissions data for all lightweight 
aggregate kiln sources. For most sources, we have compliance test 
emissions data from more than one compliance test campaign. 
Semivolatile metal stack emissions range from approximately 1 to over 
1,600 [mu]g/dscm. These emissions are expressed as mass of semivolatile 
metals (from all feedstocks) per unit volume of stack gas. Hazardous 
waste thermal emissions range from 3.0 x 10-6 to 1.1 x 
10-3 lbs per million Btu. Hazardous waste thermal emissions 
represent the mass of semivolatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste. For 
most lightweight aggregate kilns, lead was the major contributor to 
semivolatile emissions.
    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 3.1 x 10-4 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste, which considers 
emissions variability. This is an emission level that the average of 
the best performing sources could be expected to achieve in 99 of 100 
future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 71% 
of sources, and would reduce semivolatile metals emissions by 30 pounds 
per year.
    To put the proposed floor level in context for a hypothetical 
lightweight aggregate kiln that gets 90% of its required heat input 
from hazardous waste, a thermal emissions level of 3.1 x 
10-4 lbs semivolatile metals attributable to the hazardous 
waste per million Btu heat input of the hazardous waste equates 
approximately to a stack gas concentration of 300 [mu]g/dscm. This 
estimated stack gas concentration does not include contributions to 
emission from other semivolatile metals-containing materials such as 
raw materials and fossil fuels. The additional contribution to stack 
emissions of semivolatile metals in an average raw material is 
estimated to range as high as 20 to 50 [mu]g/dscm. Thus, for the 
hypothetical lightweight aggregate kiln the thermal emissions floor 
level of 3.1 x 10-4 lbs semivolatile metals attributable to 
the hazardous waste per million Btu heat input of the hazardous waste 
is estimated to be less than 350 [mu]g/dscm, which is higher than the 
current interim standard of 250 [mu]g/dscm. Given that comparing the 
proposed floor level to the interim standard requires numerous 
assumptions (as just illustrated) including hazardous waste fuel 
replacement rates, heat input requirements per ton of clinker, 
concentrations of semivolatile metals in the raw material and fuels, 
and system removal efficiency, we have included a more detailed 
analysis in the background document.\118\ Our detailed analysis 
indicates the proposed floor level could be less stringent than the 
interim standard for some sources. In order to avoid any backsliding 
from the current level of performance achieved by all lightweight 
aggregate kilns, we propose a dual standard: the semivolatile metals 
standard as both the

[[Page 21268]]

calculated floor level, expressed as a hazardous waste thermal 
emissions level, and the current interim standard. This would ensure 
that all sources are complying with a limit that is at least as 
stringent as the interim standard.
---------------------------------------------------------------------------

    \118\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards,'' 
March 2004, Chapter 23.
---------------------------------------------------------------------------

    In the September 1999 final rule, we acknowledged that a 
lightweight aggregate kiln using properly designed and operated MACT 
control technologies, including controlling the levels of metals in the 
hazardous waste, may not be capable of achieving a given emission 
standard because of mineral and process raw material contributions that 
might cause an exceedance of the emission standard. To address this 
concern, we promulgated a provision that allows 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 source from complying with 
the emission standard even though the kiln is using MACT control. See 
Sec.  63.1206(b)(9). If we were to adopt the proposed dual semivolatile 
(and low volatile) metals standards approach, we propose to retain the 
alternative standard provisions under Sec.  63.1206(b)(9) for 
semivolatile metals (and low volatile metals). We invite comment on 
this approach.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified three potential beyond-the-floor techniques for 
control of semivolatile metals: (1) Improved particulate matter 
control; (2) control of semivolatile metals in the hazardous waste 
feed; and (3) control of the semivolatile metals in the raw materials 
and fuels.
    Improved Particulate Matter Control. Controlling particulate matter 
also controls emissions of semivolatile metals. Our data show that all 
lightweight aggregate kilns are already achieving greater than 99.7% 
system removal efficiency for semivolatile metals, with many attaining 
99.9% removal. Thus, additional control of particulate matter are 
likely to result in only modest additional reductions of semivolatile 
metals emissions. We evaluated a beyond-the-floor level of 1.5 x 
10-4 lbs semivolatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste, 
which represents a 50% reduction in emissions from MACT floor levels. 
The national incremental annualized compliance cost for lightweight 
aggregate kilns to meet this beyond-the-floor level rather than to 
comply with the floor controls would be approximately $84,200 and would 
provide an incremental reduction in semivolatile metals emissions 
beyond the MACT floor controls of 20 pounds per year. Nonair quality 
health and environmental impacts and energy effects were evaluated to 
estimate the impacts between further improvements to control 
particulate matter and controls likely to be used to meet the floor 
level. We estimate that this beyond-the-floor option would increase the 
amount of solid waste generated by less than 10 tons per year and would 
also require sources to use an additional 2,000 kW-hours per year 
beyond the requirements to achieve the floor level. The costs 
associated with these impacts are accounted for in the national 
annualized compliance cost estimates. Therefore, based on these factors 
and costs of approximately $7.6 million per additional ton of 
semivolatile metals removed, we are not proposing a beyond-the-floor 
standard based on improved particulate matter control.n
    Feed Control of Semivolatile Metals in the Hazardous Waste. We also 
evaluated a beyond-the-floor level of 2.5 x 10-4 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste, which represents a 20% 
reduction from the floor level. We chose a 20% reduction as a level 
representing the practicable extent that additional feedrate control of 
semivolatile metals in hazardous waste can be used and still achieve 
appreciable emissions reductions. 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 $6,000 and would provide an incremental reduction in 
semivolatile metals emissions beyond the MACT floor controls of less 
than one pound per year. Nonair quality health and environmental 
impacts and energy effects were evaluated and are included in the 
national compliance cost estimates. Therefore, based on these factors 
and costs of approximately $20 million per additional ton of 
semivolatile metals removed, we are not proposing a beyond-the-floor 
standard based on feed control of semivolatile metals in the hazardous 
waste.
    Feed Control of Semivolatile Metals in the Raw Materials and 
Auxiliary Fuels. Lightweight aggregate kilns could achieve a reduction 
in semivolatile metal emissions by substituting a raw material 
containing lower levels of cadmium and/or lead for a primary raw 
material with higher levels of these metals. We believe that this 
beyond-the-floor option would even be less cost-effective than either 
of the options discussed above, however. Given that facilities are 
sited near the primary raw material supply, acquiring and transporting 
large quantities of an alternate source of raw materials is likely to 
be cost-prohibitive. Therefore, we are not proposing a beyond-the-floor 
standard based on limiting semivolatile metals in the raw material 
feed.
    We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of semivolatile metals would be an 
appropriate control option for sources. Two facilities typically burn 
hazardous waste at a fuel replacement rate of 100%, while one facility 
has burned a combination of fuel oil and natural gas in addition to the 
hazardous waste. We considered switching only to natural gas as the 
auxiliary fuel as a potential beyond-the-floor option. We do not 
believe that switching to natural gas is a viable control option for 
similar reasons discussed above for cement kilns.
    For the reasons discussed above, we propose to establish the 
emission standard for existing lightweight aggregate kilns at 3.1 x 
10-4 lbs semivolatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste and 
250 [mu]g/dscm.
3. What Is the Rationale for the MACT Floor for New Sources?
    Semivolatile metals emissions from new lightweight aggregate kilns 
are currently limited to 43 [mu]g/dscm by Sec.  63.1205(b)(3). This 
standard was promulgated in the Interim Standards Rule (See 67 FR at 
6797).
    The MACT floor for new sources for semivolatile metals would be 2.4 
x 10-5 lbs semivolatile metals emissions attributable to the 
hazardous waste per million Btu in the hazardous waste, which considers 
emissions variability. This is an emission level that the single best 
performing source identified with the SRE/Feed Approach could be 
expected to achieve in 99 of 100 future tests when operating under 
operating conditions identical to the compliance test conditions during 
which the emissions data were obtained.
    To put the proposed floor level in context for a hypothetical 
lightweight aggregate kiln that gets 90% of its required heat input 
from hazardous waste, a thermal emissions level of 2.4 x 
10-5 lbs semivolatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste can 
equate to a stack gas concentration as high as 60 [mu]g/dscm, including 
contributions from typical raw materials. Thus, for the

[[Page 21269]]

hypothetical lightweight aggregate kiln the thermal emissions floor 
level of 2.4 x 10-5 lbs semivolatile metals emissions 
attributable to the hazardous waste per million Btu heat input of the 
hazardous waste is estimated to be as high as 60 [mu]g/dscm, which is 
higher than the current interim standard of 43 [mu]g/dscm. In order to 
avoid any backsliding from the current level of performance for a new 
lightweight aggregate kiln source, we propose a dual standard: the 
semivolatile metals standard as both the calculated floor level, 
expressed as a hazardous waste thermal emissions level, and the current 
interim standard. This would ensure that all sources are complying with 
a limit that is at least as stringent as the interim standard. Thus, 
the proposed MACT floor for new lightweight aggregate kilns is 2.4 x 
10-5 lbs semivolatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste and 
43 [mu]g/dscm.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We identified the same three potential beyond-the-floor techniques 
for control of semivolatile metals: (1) Improved control of particulate 
matter; (2) control of semivolatile metals in the hazardous waste feed; 
and (3) control of semivolatile metals in the raw materials and fuels.
    Improved Particulate Matter Control. Controlling particulate matter 
also controls emissions of semivolatile metals. We evaluated improved 
control of particulate matter based on a state-of-the-art baghouse 
using a high quality fabric filter bag material as beyond-the-floor 
control for further reductions in semivolatile metals emissions. We 
evaluated a beyond-the-floor level of 1.2 x 10-5 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste. The incremental 
annualized compliance cost for a new lightweight aggregate kiln with 
average gas flowrate to meet this beyond-the-floor level, rather than 
to comply with the floor level, would be approximately $0.11 million 
and would provide an incremental reduction in semivolatile metals 
emissions of approximately 13 pounds per year. Nonair quality health 
and environmental impacts and energy effects were evaluated and are 
included in the cost estimates. We estimate that this beyond-the-floor 
option would increase the amount of solid waste generated by 3 tons per 
year and would also require sources to use an additional 0.3 million 
kW-hours per year beyond the requirements to achieve the floor level. 
Therefore, based on these factors and costs of approximately $18 
million per ton of semivolatile metals removed, we are not proposing a 
beyond-the-floor standard based on improved particulate matter control 
for new lightweight aggregate kilns.
    Feed Control of Semivolatile Metals in the Hazardous Waste. We also 
believe that the expense for further reduction in semivolatile metals 
emissions based on further control of semivolatile metals 
concentrations in the hazardous waste is not warranted. We considered a 
beyond-the-floor level of 1.9 x 10-5 lbs semivolatile metals 
emissions attributable to the hazardous waste per million Btu heat 
input of the hazardous waste, which represents a 20% reduction from the 
floor level. Nonair quality health and environmental impacts and energy 
effects were evaluated and are included in the compliance cost 
estimates. For similar reasons discussed above for existing sources, we 
conclude that a beyond-the-floor standard based on controlling the 
concentration of semivolatile metals levels in the hazardous waste feed 
would not be justified because of the costs and estimated emission 
reductions.
    Feed Control of Semivolatile Metals in the Raw Materials and 
Auxiliary Fuels. Lightweight aggregate kilns could achieve a reduction 
in semivolatile metals emissions by substituting a raw material 
containing lower levels of cadmium and lead for a primary raw material 
with a higher level. For a new source at an existing facility, we 
believe that this beyond-the-floor option would not be cost-effective 
due to the costs of transporting large quantities of an alternate 
source of raw material to the facility. Given that the plant site 
already exists and is sited near the source of raw material, replacing 
the raw materials at the plant site with lower semivolatile metals-
containing materials would be the source's only option. For a kiln 
constructed at a new greenfield site, we are not aware of any 
information and data from a source that has undertaken or is currently 
located at a site whose raw materials are inherently lower in 
semivolatile metals that would consistently achieve reduced 
semivolatile metals emissions. Further, we are uncertain as to what 
beyond-the-floor standard would be achievable using, if it exists, a 
lower semivolatile metals-containing raw material. Although we are 
doubtful that selecting a new plant site based on the content of metals 
in the raw material is a realistic beyond-the-floor option considering 
the numerous additional factors that go into such a decision, we 
solicit comment on whether and what level of a beyond-the-floor 
standard based on controlling the level of semivolatile metals in the 
raw materials is appropriate.
    We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of semivolatile metals would be an 
appropriate control option for sources. Two facilities typically burn 
hazardous waste at a fuel replacement rate of 100%, while one facility 
has burned a combination of fuel oil and natural gas in addition to the 
hazardous waste. We considered switching only to natural gas as the 
auxiliary fuel as a potential beyond-the-floor option. We do not 
believe that switching to natural gas is a viable control option for 
the same reasons discussed above for cement kilns.
    For the reasons discussed above, we propose to establish the 
emission standard for new lightweight aggregate kilns at 2.4 x 
10-5 lbs semivolatile metals emissions attributable to the 
hazardous waste per million Btu heat content in the hazardous waste and 
43 [mu]g/dscm.

E. What Are the Proposed Standards for Low Volatile Metals?

    We are proposing to establish standards for existing lightweight 
aggregate kilns that limit emissions of low volatile metals (arsenic, 
beryllium, and chromium) to 9.5 x 10-5 lbs low volatile 
metals emissions attributable to the hazardous waste per million Btu 
heat input of the hazardous waste and 110 [mu]g/dscm. The proposed 
standard for new sources is 3.2 x 10-5 lbs low volatile 
metals emissions attributable to the hazardous waste per million Btu 
heat input of the hazardous waste and 110 [mu]g/dscm.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Low volatile metals emissions from existing lightweight aggregate 
kilns are currently limited to 110 [mu]g/dscm by Sec.  63.1205(a)(4). 
This standard was promulgated in the Interim Standards Rule (see 67 FR 
at 6797). Lightweight aggregate kilns control emissions of low volatile 
metals with baghouses and/or by controlling the feed concentration of 
low volatile metals in the hazardous waste.
    We have compliance test emissions data for all lightweight 
aggregate kiln sources. For most sources, we have compliance test 
emissions data from more than one compliance test campaign. Low 
volatile metal stack emissions range from approximately 16 to 200 
[mu]g/dscm. These emissions are expressed as mass of low volatile 
metals (from all feedstocks) per unit volume of

[[Page 21270]]

stack gas. Hazardous waste thermal emissions range from 9.7 x 
10-6 to 1.8 x 10-4 lbs per million Btu. Hazardous 
waste thermal emissions represent the mass of low volatile metals 
emissions attributable to the hazardous waste per million Btu heat 
input of the hazardous waste. For most lightweight aggregate kilns, 
chromium was the major contributor to low volatile emissions.
    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 9.5 x 10-5 lbs 
low volatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste, which considers 
emissions variability. This is an emission level that the average of 
the best performing sources could be expected to achieve in 99 of 100 
future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 57% 
of sources and would reduce low volatile metals emissions by 30 pounds 
per year.
    To put the proposed floor level in context for a hypothetical 
lightweight aggregate kiln that gets 90% of its required heat input 
from hazardous waste, a thermal emissions level of 9.5 x 
10-5 lbs low volatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste 
equates approximately to a stack gas concentration of 90 [mu]g/dscm. 
This estimated stack gas concentration does not include contributions 
to emission from other low volatile metals-containing materials such as 
raw materials. The additional contribution to stack emissions of low 
volatile metals in an average raw material is estimated to be 50 [mu]g/
dscm. Thus, for the hypothetical lightweight aggregate kiln the thermal 
emissions floor level of 9.5 x 10-5 lbs low volatile metals 
emissions attributable to the hazardous waste per million Btu heat 
input of the hazardous waste is estimated to be 150 [mu]g/dscm, which 
is higher than the current interim standard of 110 [mu]g/dscm. Given 
that comparing the proposed floor level to the interim standard 
requires numerous assumptions including hazardous waste fuel 
replacement rates, heat input requirements per ton of clinker, 
concentrations of low volatile metals in the raw material and fuels, 
and system removal efficiency, we have included a more detailed 
analysis in the background document.\119\ Our detailed analysis 
indicates the proposed floor level could be less stringent than the 
interim standard for some sources. In order to avoid any backsliding 
from the current level of performance achieved by all lightweight 
aggregate kilns, we propose a dual standard: the low volatile metals 
standard as both the calculated floor level, expressed as a hazardous 
waste thermal emissions level, and the current interim standard. This 
would ensure that all sources are complying with a limit that is at 
least as stringent as the interim standard.
---------------------------------------------------------------------------

    \119\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards,'' 
March 2004, Chapter 23.
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified three potential beyond-the-floor techniques for 
control of low volatile metals: (1) Improved particulate matter 
control; (2) control of low volatile metals in the hazardous waste 
feed; and (3) control of the low volatile metals in the raw materials 
and fuels.
    Improved Particulate Matter Control. Controlling particulate matter 
also controls emissions of low volatile metals. Our data show that all 
lightweight aggregate kilns are already achieving greater than 99.8% 
system removal efficiency for low volatile metals, with many attaining 
99.9% or greater removal. Thus, additional control of particulate 
matter emissions is likely to result in only a small increment in 
reduction of low volatile metals emissions. We evaluated a beyond-the-
floor level of 4.7 x 10-5 lbs low volatile metals emissions 
attributable to the hazardous waste per million Btu heat input of the 
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 $0.24 
million and would provide an incremental reduction in low volatile 
metals emissions beyond the MACT floor controls of 28 pounds per year. 
Nonair quality health and environmental impacts and energy effects were 
evaluated to estimate the impacts between further improvements to 
control particulate matter and controls likely to be used to meet the 
floor level. We estimate that this beyond-the-floor option would 
increase the amount of solid waste generated by less than 30 tons per 
year and would also require sources to use an additional 46,000 kW-
hours of energy per year. Therefore, based on these factors and costs 
of approximately $17 million per additional ton of low volatile metals 
removed, we are not proposing a beyond-the-floor standard based on 
improved particulate matter control.
    Feed Control of Low Volatile Metals in the Hazardous Waste. We also 
evaluated a beyond-the-floor level of 7.6 x 10-5 lbs low 
volatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste, which represents a 20% 
reduction from the floor level. We chose a 20% reduction as a level 
representing the practicable extent that additional feedrate control of 
low volatile metals in hazardous waste (beyond feedrate control that 
may be necessary to achieve the floor level) can be used and still 
achieve modest emissions reductions. 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 $150,000 and would provide an incremental reduction in 
low volatile metals emissions beyond the MACT floor controls of 14 
pounds per year. Nonair quality health and environmental impacts and 
energy effects were considered and are included in the cost estimates. 
Therefore, based on these factors and costs of approximately $22 
million per additional ton of low volatile metals removed, we are not 
proposing a beyond-the-floor standard based on feed control of low 
volatile metals in the hazardous waste.
    Feed Control of Low Volatile Metals in the Raw Materials and 
Auxiliary Fuels. Lightweight aggregate kilns could achieve a reduction 
in low volatile metal emissions by substituting a raw 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 even be less cost-effective 
than either of the options discussed above, however. Given that 
facilities are sited near the primary raw material supply, acquiring 
and transporting large quantities of an alternate source of raw 
materials is likely to be cost-prohibitive. Therefore, we are not 
proposing a beyond-the-floor standard based on limiting low volatile 
metals in the raw material feed.
    We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of low volatile metals would be an 
appropriate control option for sources. Two facilities typically burn 
hazardous waste at a fuel replacement rate of 100%, while one facility 
has burned a combination of fuel oil and natural gas in addition to the 
hazardous waste. We considered switching only to natural gas as the 
auxiliary fuel as a potential beyond-the-

[[Page 21271]]

floor option. We do not believe that switching to natural gas is a 
viable control option for similar reasons discussed above for cement 
kilns.
    For the reasons discussed above, we propose to establish the 
emission standard for existing lightweight aggregate kilns at 9.5 x 
10-5 lbs low volatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste and 
110 [mu]g/dscm.
3. What Is the Rationale for the MACT Floor for New Sources?
    Low volatile metals emissions from new lightweight aggregate kilns 
are currently limited to 110 [mu]g/dscm by Sec.  63.1205(b)(4). This 
standard was promulgated in the Interim Standards Rule (See 67 FR at 
6797).
    The MACT floor for new sources for low volatile metals would be 3.2 
x 10-5 lbs low volatile metals emissions in the hazardous 
waste per million Btu in the hazardous waste, which considers emissions 
variability. This is an emission level that the single best performing 
source identified with the SRE/Feed Approach could be expected to 
achieve in 99 of 100 future tests when operating under operating 
conditions identical to the compliance test conditions during which the 
emissions data were obtained.
    As discussed for existing sources, in order to avoid any 
backsliding from the current level of performance for a new lightweight 
aggregate kiln source, we propose a dual standard: the low volatile 
metals standard as both the calculated floor level, expressed as a 
hazardous waste thermal emissions level, and the current interim 
standard. This would ensure that all sources are complying with a limit 
that is at least as stringent as the interim standard. Thus, the 
proposed MACT floor for new lightweight aggregate kilns is 3.2 x 
10-5 lbs low volatile metals emissions attributable to the 
hazardous waste per million Btu heat input of the hazardous waste and 
110 [mu]g/dscm.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We considered three potential beyond-the-floor techniques for 
control of low volatile metals: (1) Improved particulate matter 
control; (2) control of low volatile metals in the hazardous waste 
feed; and (3) control of the low volatile metals in the raw materials 
and fuels.
    Improved Particulate Matter Control. Controlling particulate matter 
also controls emissions of low volatile metals. We evaluated improved 
control of particulate matter based on a state-of-the-art baghouse 
using a high quality fabric filter bag material as beyond-the-floor 
control for further reductions in low volatile metals emissions. We 
evaluated a beyond-the-floor level of 1.6 x 10-5 lbs low 
volatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste. The incremental 
annualized compliance cost for a new lightweight aggregate kiln with 
average gas flowrate to meet this beyond-the-floor level, rather than 
to comply with the floor level, would be approximately $0.11 million 
and would provide an incremental reduction in low volatile metals 
emissions of approximately 16 pounds per year. Nonair quality health 
and environmental impacts and energy effects were evaluated and are 
included in the cost estimates. We estimate that this beyond-the-floor 
option would increase the amount of solid waste generated by 3 tons per 
year and would also require sources to use an additional 0.3 million 
kW-hours per year beyond the requirements to achieve the floor level. 
Therefore, based on these factors and costs of nearly $14 million per 
ton of low volatile metals removed, we are not proposing a beyond-the-
floor standard based on improved particulate matter control for new 
lightweight aggregate kilns.
    Feed Control of Low Volatile Metals in the Hazardous Waste. We also 
believe that the expense for further reduction in low volatile metals 
emissions based on further control of low volatile metals 
concentrations in the hazardous waste is not warranted. We considered a 
beyond-the-floor level of 2.6 x 10-5 lbs low volatile metals 
emissions attributable to the hazardous waste per million Btu heat 
input of the hazardous waste, which represents a 20% reduction from the 
floor level. Nonair quality health and environmental impacts and energy 
effects were evaluated and are included in the compliance cost 
estimates. For similar reasons discussed above for existing sources, we 
conclude that a beyond-the-floor standard based on controlling the 
concentration of low volatile metals levels in the hazardous waste feed 
would not be justified because of the costs and estimated emission 
reductions.
    Feed Control of Low Volatile Metals in the Raw Materials and 
Auxiliary Fuels. Lightweight aggregate kilns could achieve a reduction 
in low volatile metals emissions by substituting a raw material 
containing lower levels of arsenic, beryllium, and/or chromium for a 
primary raw material with a higher level. For a new source at an 
existing facility, we believe that this beyond-the-floor option would 
not be cost-effective due to the costs of transporting large quantities 
of an alternate source of raw material to the facility. Given that the 
plant site already exists and is sited near the source of raw material, 
replacing the raw materials at the plant site with lower low volatile 
metals-containing materials would be the source's only option. For a 
kiln constructed at a new greenfield site, we are not aware of any 
information and data from a source that has undertaken or is currently 
located at a site whose raw materials are inherently lower in low 
volatile metals that would consistently achieve reduced low volatile 
metals emissions. Further, we are uncertain as to what beyond-the-floor 
standard would be achievable using, if it exists, a lower low volatile 
metals-containing raw material. Although we are doubtful that selecting 
a new plant site based on the content of metals in the raw material is 
a realistic beyond-the-floor option considering the numerous additional 
factors that go into such a decision, we solicit comment on whether and 
what level of a beyond-the-floor standard based on controlling the 
level of low volatile metals in the raw materials is appropriate.
    We also considered whether fuel switching to an auxiliary fuel 
containing a lower concentration of low volatile metals would be an 
appropriate control option for sources. Two facilities typically burn 
hazardous waste at a fuel replacement rate of 100%, while one facility 
has burned a combination of fuel oil and natural gas in addition to the 
hazardous waste. We considered switching only to natural gas as the 
auxiliary fuel as a potential beyond-the-floor option. We do not 
believe that switching to natural gas is a viable control option for 
the same reasons discussed above for cement kilns.
    For the reasons discussed above, we propose to establish the 
emission standard for new lightweight aggregate kilns at 3.2 x 
10-\5\ lbs low volatile metals emissions attributable to the 
hazardous waste per million Btu heat content in the hazardous waste and 
110 [mu]g/dscm.

F. What Are the Proposed Standards for Hydrogen Chloride and Chlorine 
Gas?

    We are proposing to establish standards for existing and new 
lightweight aggregate kilns that limit total chlorine emissions 
(hydrogen chloride and chlorine gas, combined, reported as a chloride 
equivalent) to 600 ppmv. Although we are also proposing to invoke CAA 
section 112(d)(4) to establish alternative risk-based standards in lieu 
of the MACT emission standards for total chlorine, the risk-based 
standards would be capped at the

[[Page 21272]]

interim standards. Given that we are proposing MACT standards 
equivalent to the interim standards--600 ppmv, an emission level you 
are currently achieving--you would not be eligible for the section 
112(d)(4) risk-based standards. See Part Two, Section XIII for 
additional details.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Total chlorine emissions from existing cement kilns are limited to 
600 ppmv by Sec.  63.1205(a)(6). This standard was promulgated in the 
Interim Standards Rule (See 67 FR at 6797). One of the three 
lightweight aggregate facilities uses a venturi scrubber to remove 
total chlorine from the gas stream. The system removal efficiency (SRE) 
achieved by this facility during compliance testing shows removal 
efficiencies ranging from 96 to 99%. Sources at the other two 
facilities do not use air pollution control equipment to capture 
emissions of total chlorine, and, therefore, SREs are negligible.
    The majority of the chlorine fed to the lightweight aggregate kiln 
during a compliance test comes from the hazardous waste. In all but a 
few cases the hazardous waste contribution to the total amount of 
chlorine fed to the kiln represented at least 80% of the total loading 
to the kiln. The proposed MACT floor control for total chlorine is, in 
part, based on controlling the concentration of chlorine in the 
hazardous waste. The chlorine concentration in the hazardous waste will 
affect emissions of total chlorine at a given SRE because emissions 
will increase as the chlorine loading increases.
    We have compliance test emissions data for all lightweight 
aggregate kiln sources. For most sources, we have compliance test 
emissions data from more than one compliance test campaign. Total 
chlorine emissions range from 14 to 116 ppmv for the source using a 
venturi scrubber and range from 500 to 2,400 ppmv at sources without 
scrubbing control equipment.
    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 3.0 lbs total chlorine 
emissions attributable to the hazardous waste per million Btu heat 
input of the hazardous waste, which considers emissions variability. 
This is an emission level that the average of the best performing 
sources could be expected to achieve in 99 of 100 future tests when 
operating under conditions identical to the compliance test conditions 
during which the emissions data were obtained.
    To put the proposed floor level in context for a hypothetical 
lightweight aggregate kiln that gets 90% of its required heat input 
from hazardous waste, a thermal emissions level of 3.0 lbs total 
chlorine emissions attributable to the hazardous waste per million Btu 
heat input of the hazardous waste equates approximately to a stack gas 
concentration of 1,970 ppmv. This estimated stack gas concentration 
does not include contributions to emission from other chlorine-
containing materials such as raw materials. Given that the calculated 
floor level is less stringent than the current interim emission 
standard of 600 ppmv. In order to avoid any backsliding from the 
current level of performance achieved by all lightweight aggregate 
kilns, we are proposing the floor standard as the current emission 
standard of 600 ppmv. This emission level is currently being achieved 
by all sources.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We considered a beyond-the-floor standard of 150 ppmv based on the 
assumption that dry lime scrubbing will provide 75% control of hydrogen 
chloride.\120\ In addition, for costing purposes we assumed that 
lightweight aggregate kilns needing total chlorine reductions to 
achieve the beyond-the-floor level would install the dry scrubbing 
system after the existing particulate matter control device and add a 
new, smaller baghouse to remove the products of the reaction and any 
unreacted lime. We chose this conservative costing approach to address 
potential concerns that unreacted lime and collected chloride and 
sulfur salts may interfere with lightweight aggregate dust use 
practices.
---------------------------------------------------------------------------

    \120\ We also considered controlling the chlorine levels in the 
hazardous waste feed and controlling the chlorine levels in the raw 
materials as potential beyond-the-floor techniques; however, it is 
our judgment that they are not likely to be as cost-effective as dry 
lime scrubbing.
---------------------------------------------------------------------------

    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 $1.9 million and would 
provide an incremental reduction in total chlorine emissions beyond the 
MACT floor controls of 280 tons per year, for a cost-effectiveness of 
$6,800 per additional ton of total chlorine removed. We evaluated 
nonair quality health and environmental impacts and energy effects 
associated with this beyond-the-floor standard and estimate that this 
beyond-the-floor option would increase the amount of solid waste 
generated by 12,700 tons per year and would also require sources to use 
an additional 175,000 kW-hours per year and 31 million gallons of water 
beyond the requirements to achieve the floor level.
    We note that a cost of $6,800 per additional ton of total chlorine 
removed is in the ``grey area'' between a cost the Agency has concluded 
is cost-effective and a cost the Agency has concluded is not cost-
effective under other MACT rules. EPA concluded that a cost of $1,100 
per ton of total chlorine removed for hazardous waste burning 
lightweight aggregate kilns was cost-effective in the 1999 MACT final 
rule. See 68 FR at 52900. EPA concluded, however, that a cost of 
$45,000 per ton of hydrogen chloride removed was not cost-effective for 
industrial boilers. See 68 FR at 1677. Consequently, we are concerned 
that a cost of $6,800 per additional ton of total chlorine removed is 
not warranted. Therefore, after considering cost-effectiveness and 
nonair quality health and environmental impacts and energy effects, we 
are not proposing a beyond-the-floor standard.
    We specifically request comment on whether a beyond-the-floor 
standard is warranted.
3. What Is the Rationale for the MACT Floor for New Sources?
    Total chlorine emissions from new lightweight aggregate kilns are 
currently limited to 600 ppmv by Sec.  63.1205(b)(6). This standard was 
promulgated in the Interim Standards Rule (See 67 FR at 6797). The MACT 
floor for new sources for total chlorine would be 0.93 lbs chlorine in 
the hazardous waste per million Btu in the hazardous waste, which 
considers emissions variability.
    To put the proposed floor level in context for a hypothetical 
lightweight aggregate kiln that gets 90% of its required heat input 
from hazardous waste, a thermal emissions level of 0.93 lbs total 
chlorine emissions attributable to the hazardous waste per million Btu 
heat input of the hazardous waste equates approximately to a stack gas 
concentration of 610 ppmv. This estimated stack gas concentration does 
not include contributions to emission from other chlorine-containing 
materials such as raw materials. Given that the calculated floor level 
is less stringent than the current interim emission standard of 600 
ppmv. In order to avoid any backsliding from the current standard for a 
new lightweight aggregate kilns, we are proposing the floor standard as 
the current emission standard of 600 ppmv.

[[Page 21273]]

4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    Similar to existing sources, we considered a beyond-the-floor 
standard of 150 ppmv based on the assumption that dry lime scrubbing 
will provide 75% control of hydrogen chloride. The incremental 
annualized compliance cost for a new lightweight aggregate kiln with 
average gas flowrate to meet this beyond-the-floor level, rather than 
to comply with the floor level, would be approximately $0.42 million 
and would provide an incremental reduction in total chlorine emissions 
of approximately 150 tons per year for a cost-effectiveness of 
approximately $2,800 per additional ton of total chlorine removed. 
Nonair quality health and environmental impacts and energy effects were 
evaluated and are included in the cost estimates. We estimate that this 
beyond-the-floor option would increase the amount of solid waste 
generated by 23 tons per year and would also require sources to use an 
additional 0.3 million kW-hours per year and 2 million gallons of water 
beyond the requirements to achieve the floor level.
    A cost of $2,800 per additional ton of total chlorine removed is in 
the ``grey area'' between a cost the Agency has concluded is cost-
effective and a cost the Agency has concluded is not cost-effective 
under other MACT rules, as discussed above. Therefore, we are concerned 
that a cost-effectiveness of $2,800 per additional ton of total 
chlorine removed may not be warranted. After considering cost-
effectiveness and nonair quality health and environmental impacts and 
energy effects, we are not proposing a beyond-the-floor standard.
    We specifically request comment on whether a beyond-the-floor 
standard is warranted.

G. What Are the Standards for Hydrocarbons and Carbon Monoxide?

    Hydrocarbon and carbon monoxide standards are surrogates to control 
emissions of organic hazardous air pollutants for existing and new 
lightweight aggregate kilns. The standards limit hydrocarbons and 
carbon monoxide concentrations to 20 ppmv or 100 ppmv. See Sec. Sec.  
63.1205(a)(5) and (b)(5). Existing and new lightweight aggregate kilns 
can elect to comply with either the hydrocarbon limit or the carbon 
monoxide limit on a continuous basis. Sources that 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. The rationale for these decisions 
are discussed in the September 1999 final rule (64 FR at 52900). We 
view the standards for hydrocarbons and carbon monoxide as unaffected 
by the Court's vacature of the challenged regulations in its decision 
of July 24, 2001. We therefore are not proposing these standards for 
lightweight aggregate kilns, but rather are mentioning them here for 
the reader's convenience.
H. What Are the Standards for Destruction and Removal Efficiency?
    The destruction and removal efficiency (DRE) standard is a 
surrogate to control emissions of organic hazardous air pollutants 
other than dioxin/furans. The standard for existing and new lightweight 
aggregate kilns requires 99.99% DRE for each principal organic 
hazardous constituent, except that 99.9999% DRE is required if 
specified dioxin-listed hazardous wastes are burned. See Sec. Sec.  
63.1205(c). The rationale for these decisions are discussed in the 
September 1999 final rule (64 FR at 52902). We view the standards for 
DRE as unaffected by the Court's vacature of the challenged regulations 
in its decision of July 24, 2001. We therefore are not proposing these 
standards for lightweight aggregate kilns, but rather are mentioning 
them here for the reader's convenience.

X. How Did EPA Determine the Proposed Emission Standards for Hazardous 
Waste Burning Solid Fuel-Fired Boilers?

    The proposed standards for existing and new solid fuel-fired 
boilers that burn hazardous waste are summarized in the table below. 
See proposed Sec.  63.1216.

    Proposed Standards for Existing and New Solid Fuel-Fired Boilers
------------------------------------------------------------------------
                                         Emission standard \1\
 Hazardous air pollutant  or -------------------------------------------
          surrogate             Existing sources         New sources
------------------------------------------------------------------------
Dioxin and furan............  100 ppmv carbon       100 ppmv carbon
                               monoxide or 10 ppmv   monoxide or 10 ppmv
                               hydrocarbons..        hydrocarbons.
Mercury.....................  10 [mu]g/dscm.......  10 [mu]g/dscm.
Particulate matter..........  69 mg/dscm (0.030 gr/ 34 mg/dscm (0.015 gr/
                               dscf).                dscf).
Semivolatile metals.........  170 [mu]g/dscm......  170 [mu]g/dscm.
Low volatile metals.........  210 [mu]g/dscm......  190 [mu]g/dscm.
Hydrogen chloride and         440 ppmv or the       73 ppmv or the
 chlorine gas \2\.             alternative           alternative
                               emission limits       emission limits
                               under Sec.            under Sec.
                               63.1215.              63.1215.
Carbon monoxide or            100 ppmv carbon       100 ppmv carbon
 hydrocarbons \3\.             monoxide or 10 ppmv   monoxide or 10 ppmv
                               hydrocarbons.         hydrocarbons.
-----------------------------
Destruction and Removal       For existing and new sources, 99.99% for
 Efficiency.                   each principal organic hazardous
                               constituent (POHC). For sources burning
                               hazardous wastes F020, F021, F022, F023,
                               F026, or F027, however, 99.9999% for each
                               POHC.
------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen, dry basis.
\2\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\3\ Hourly rolling average. Hydrocarbons reported as propane.

    We considered whether fuel switching could be considered a control 
technology to achieve MACT floor control. We investigated whether fuel 
switching would achieve lower HAP emissions and whether it could be 
technically achieved considering the existing design of solid fuel-
fired boilers. We also considered the availability of various types of 
fuel. After considering these factors, we determined that fuel 
switching is not an appropriate control technology for purposes of 
determining the MACT floor level of control. This decision is based on 
the overall effect of fuel switching on HAP emissions, technical

[[Page 21274]]

and design considerations, and concerns about fuel availability.
    We determined that while fuel switching from coal to natural gas or 
oil would decrease particulate matter and some metal HAP emissions, 
emissions of some organic HAP would increase, resulting in uncertain 
benefits.\121\ We believe that it is inappropriate in a MACT rulemaking 
to consider as MACT a control option that potentially will decrease 
emissions of one HAP while increasing emissions of another HAP. In 
order to adopt such a strategy, we would need to assess the relative 
risk associated with each HAP emitted, and determine whether requiring 
the control in question would result in overall lower risk. Such an 
analysis is not appropriate at this stage in the regulatory process. 
For example, the term ``clean coal'' refers to coal that is lower in 
sulfur content and not necessarily lower in HAP content. Data gathered 
by EPA also indicates that within specific coal types HAP content can 
vary significantly. Switching to a low sulfur coal may actually 
increase emissions of some HAP. Therefore, it is not appropriate for 
EPA to include fuel switching to a low sulfur coal as part of the MACT 
standards for boilers that burn hazardous waste.
---------------------------------------------------------------------------

    \121\ C. Leatherwood, ERG, to J. Eddinger, OAQPS, EPA, 
Memorandum: Development of Fuel Switching Costs and Emission 
Reductions for Industrial/Commercial/Institutional Boilers and 
Process Heaters National Emission Standards for Hazardous Air 
Pollutants, October 2002.
---------------------------------------------------------------------------

    We also considered the availability of alternative fuel types. 
Natural gas pipelines are not available in all regions of the U.S., and 
natural gas is simply not available as a fuel for many solid fuel-fired 
boilers. Moreover, even where pipelines provide access to natural gas, 
supplies of natural gas may not be adequate. For example, it is common 
practice in cities during winter months (or periods of peak demand) to 
prioritize natural gas usage for residential areas before industrial 
usage. Requiring EPA regulated combustion units to switch to natural 
gas would place an even greater strain on natural gas resources. 
Consequently, even where pipelines exist, some units would not be able 
to run at normal or full capacity during these times if shortages were 
to occur. Therefore, under any circumstances, there would be some units 
that could not comply with a requirement to switch to natural gas.
    In addition, we have significant concern that switching fuels would 
be infeasible for sources designed and operated to burn specific fuel 
types. Changes in the type of fuel burned by a boiler may require 
extensive changes to the fuel handling and feeding system (e.g., a 
stoker-fired boiler using coal as primary fuel would need to be 
redesigned to handle fuel oil or gaseous fuel as the primary fuel). 
Additionally, burners and combustion chamber designs are generally not 
capable of handling different fuel types, and generally cannot 
accommodate increases or decreases in the fuel volume and shape. Design 
changes to allow different fuel use, in some cases, may reduce the 
capacity and efficiency of the boiler. Reduced efficiency may result in 
less complete combustion and, thus, an increase in organic HAP 
emissions. For the reasons discussed above, we conclude that fuel 
switching to cleaner solid fuels or to liquid or gaseous fuels is not 
an appropriate criteria for identifying the MACT floor level of control 
for solid fuel-fired boilers.

A. What Is the Rationale for the Proposed Standards for Dioxin and 
Furan?

    The proposed standard for dioxin/furan for existing and new sources 
is compliance with the proposed carbon monoxide or hydrocarbon (CO/HC) 
emission standard and compliance with the proposed destruction and 
removal efficiency (DRE) standard. The CO/HC and DRE standards control 
emissions of organic HAPs in general, and are discussed in Sections G 
and H below. This standard ensures that boilers operate under good 
combustion practices as a surrogate for dioxin/furan control. Operating 
under good combustion practices minimizes levels of products of 
incomplete combustion, including potentially dioxin/furan, and organic 
compounds that could be precursors for post-combustion formation of 
dioxin/furan. The rationale for the dioxin/furan standard is discussed 
below.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    The proposed MACT floor control for existing sources is compliance 
with the proposed CO/HC emission standard and compliance with the 
proposed DRE standard.
    Solid fuel-fired boilers that burn hazardous waste cofire the 
hazardous waste with coal at firing rates of 6-33% of total heat input. 
We have dioxin/furan emission data for one source, and those emissions 
are 0.07 ng TEQ/dscm.
    Although dioxin/furan can be formed post-combustion in an 
electrostatic precipitator or baghouse that is operated at temperatures 
within the range of 400[deg] to 750[deg]F, the boiler for which we have 
dioxin/furan emissions data is equipped with an electrostatic 
precipitator that operated at 500[deg]F during the emissions test. 
Although this is well within the optimum temperature range for 
formation of dioxin/furan, dioxin/furan emissions were low. In 
addition, this boiler fed chlorine at levels four times greater than 
any other solid fuel boiler.\122\ We also have emissions data from 16 
nonhazardous waste coal-fired boilers equipped with electrostatic 
precipitators and baghouses operated at temperatures up to 480[deg]F, 
all of which have dioxin/furan emissions below 0.3 ng TEQ/dscm.\123\ We 
conclude from these data and the information discussed below that rapid 
quench of post-combustion gas temperatures to below 400[deg]F--the 
control technique that is the basis for the MACT standards for 
hazardous waste burning incinerators, and cement and lightweight 
aggregate kilns--is not the dominant dioxin/furan control mechanism for 
coal-fired boilers.
---------------------------------------------------------------------------

    \122\ Uncontrolled hydrogen chloride in combustion gas was 
approximately 700 ppmv.
    \123\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards,'' 
March 2004, Chapter 2.
---------------------------------------------------------------------------

    We believe that sulfur contributed by the coal fuel is a dominant 
control mechanism by inhibiting formation of dioxin/furan. Coal 
generally contributes from 65% to 95% percent of the boiler's heat 
input with the remainder provided by hazardous waste fuel. The presence 
of sulfur in combustor feedstocks has been shown to dramatically 
inhibit the catalytic formation of dioxin/furan in downstream 
temperature zones from 400[deg]F to 750[deg]F. High sulfur coals tend 
to inhibit dioxin/furan formation better than low sulfur coals. Id.
    Adsorption of any dioxin/furan that may be formed on coal fly ash, 
and subsequent capture in the electrostatic precipitator or baghouse, 
also may contribute to the low dioxin/furan emissions despite some 
boilers operating at relatively high back-end gas temperatures. This 
effect is similar to that of using activated carbon injection to 
control dioxin/furan emissions. Adsorption of dioxin/furan on fly ash 
is related to the carbon content of the fly ash, and, thus, the type of 
coal burned. Id.
    Operating under good combustion conditions to minimize emissions of 
organic compounds such as polychlorinated biphenols, benzene, and 
phenol that can be precursors to dioxin/furan formation is an important 
requisite to control dioxin/furan emissions. Although sulfur-induced 
inhibition may be the dominant mechanism to control dioxin/furan

[[Page 21275]]

emissions from coal-fired boilers, minimizing dioxin/furan precursors 
by operating under good combustion practices certainly plays a part in 
controlling dioxin/furan emissions.
    We propose to use the CO/HC and DRE standards as surrogates to 
ensure that boilers operate under good combustion conditions because 
quantified levels of control provided by sulfur in the coal and 
adsorption onto collected fly ash may not be replicable by the best 
performing sources nor duplicable by other sources. Although coal 
sulfur content may be a dominant factor affecting dioxin/furan 
emissions, we do not know what minimum level of sulfur provides 
significant control. Moreover, sulfur in coal causes emissions of 
sulfur oxides, a major criteria pollutant, and particulate sulfates. 
Similarly, we cannot quantify a minimum carbon content of coal that 
would form carbonaceous fly ash with superior dioxin/furan adsorptive 
properties. In addition, restricting coal types that may be burned 
based on carbon content may have an adverse impact on energy production 
at sources burning hazardous waste as fuel. (These considerations raise 
the question of whether boilers operating under these conditions would 
still be ``best'' performers when these adverse impacts are taken into 
account.) For these reasons, and because we have emissions data from 
only one source, we cannot establish a numerical dioxin/furan emission 
standard.
    Operating under good combustion practices is floor control because 
all hazardous waste burning boilers are required by existing RCRA 
regulations to operate under good combustion conditions to minimize 
emissions of toxic organic compounds. See Sec.  266.104 requiring 
compliance with DRE and CO/HC emission standards.\124\ We also find, as 
required by CAA section 112(h)(1), that these proposed standards are 
consistent with section 112(d)'s objective of reducing emissions of 
these HAPs to the extent achievable.
---------------------------------------------------------------------------

    \124\ Section 266.104 requires compliance with a CO limit of 100 
ppmv or a HC limit of 20 ppmv, while we are proposing today a CO 
limit of 100 ppmv or a HC limit of 10 ppmv (see Section X.H in the 
text). Although today's proposed HC limit is more stringent than the 
current limit for boilers, all solid fuel boilers chose to comply 
with the 100 ppmv CO limit. Moreover, for those liquid-fuel fired 
boilers that chose to comply with the 20 ppmv HC limit, their HC 
emissions are below 10 ppmv.
---------------------------------------------------------------------------

    We request comment on an alternative floor that would be 
established as the highest dioxin/furan emission level in our data 
base. Because we have dioxin/furan emission data from only one coal-
fired boiler that burns hazardous waste, we would combine that data 
point with emissions data from coal-fired boilers that do not burn 
hazardous waste since the factors that affect dioxin/furan emissions 
from these boilers are not significantly influenced by hazardous waste. 
These additional data would better represent the range of emissions 
from coal-fired boilers. Under this approach, the dioxin/furan floor 
would be an emission level of 0.30 ng TEQ/dscm. We would also use this 
approach to establish the same floor for new sources.
    Finally, we note that we propose to require a one-time dioxin/furan 
emission test for sources that would not be subject to a numerical 
dioxin/furan emission standard, such as solid fuel-fired boilers. As 
discussed in Part Two, Section XIV.B below, the testing would assist in 
developing both section 112(d)(6) standards and section 112(f) residual 
risk standards.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    As discussed above, we propose to use the CO/HC and DRE standards 
as surrogates to ensure good combustion conditions, and thus, control 
of dioxin/furan emissions. We are not proposing beyond-the-floor 
standards for CO/HC and DRE, as discussion in Sections G and H below.
    We investigated use of activated carbon injection or, for sources 
equipped with baghouses, catalytically impregnated fabric felt/membrane 
filter materials to achieve a beyond-the-floor standard of 0.10 ng TEQ/
dscm.\125\ To estimate the cost-effectiveness of these beyond-the-floor 
control techniques, we imputed dioxin/furan emissions levels for the 
six sources for which we don't have measured emissions data. To impute 
the missing emissions levels, we used the emissions data from the 
hazardous waste burning boiler as well as the emissions data from 
nonhazardous waste coal-fired boilers. It may be appropriate to meld 
these emissions data because hazardous waste burning should not affect 
dioxin/furan emissions from coal-fired boilers. In fact, the 
nonhazardous waste coal-fired boilers had somewhat higher emissions 
than the hazardous waste coal-fired boiler. (The emissions from the 
nonhazardous waste coal-fired boilers may simply represent the range of 
emissions that could be expected from hazardous waste coal-fired 
boilers, as well, given that we have emissions data from only one 
hazardous waste boiler.)
---------------------------------------------------------------------------

    \125\ We considered a beyond-the-floor standard of 0.20 ng TEQ/
dscm but determined that it may not result in emissions reductions 
because the majority of sources (the hazardous waste coal-fired 
boiler and the nonhazardous waste coal-fired boilers) appear to emit 
dioxin/furan at levels below 0.20 ng TEQ/dscm.
---------------------------------------------------------------------------

    The national incremental annualized compliance cost for solid fuel-
fired boilers to meet this beyond-the-floor level rather than comply 
with the floor controls would be approximately $3.4 million and would 
provide an incremental reduction in dioxin/furan emissions beyond the 
MACT floor controls of 0.26 grams TEQ tons per year. We also evaluated 
the nonair quality health and environmental impacts and energy effects 
between activated carbon injection and controls likely to be used to 
meet the floor level. We estimate that this beyond-the-floor option 
would increase the amount of hazardous waste \126\ generated by 3,300 
tons per year and would also require sources to use an additional 1.2 
million kW-hours per year. Based on these impacts and costs of 
approximately $13 million per additional grams of dioxin/furan removed, 
we are not proposing a beyond-the-floor standard based on activated 
carbon injection.
---------------------------------------------------------------------------

    \126\ To estimate the cost of a beyond-the-floor standard 
conservatively, we assumed the solid waste generated would be 
subject to regulation as hazardous waste. These costs are likely 
over-estimated, however, because these residues are not likely to 
fail the criteria for retaining the Bevill exclusion under 40 CFR 
266.112.
---------------------------------------------------------------------------

    For these reasons, we propose a floor standard for dioxin/furan for 
existing sources of compliance with the proposed CO/HC emission 
standard and compliance with the proposed DRE standard.\127\
---------------------------------------------------------------------------

    \127\ We note that we propose to require solid fuel-fired 
boilers (and liquid fuel-fired boilers that are not subject to a 
numerical dioxin/furan standard) to conduct a one-time dioxin/furan 
emission test to provide data to assist in developing both section 
112(d)(6) standards and section 112(f) residual risk standards. See 
discussion in Section XIV.B of the preamble.
---------------------------------------------------------------------------

3. What Is the Rationale for the MACT Floor for New Sources?
    As discussed above, we propose to use the CO/HC and DRE standards 
as surrogates to ensure good combustion conditions, and thus, control 
of dioxin/furan emissions. Because we are proposing the same DRE and 
CO/HC standards for existing sources and new sources as discussion in 
Sections G and H below, we are proposing the same dioxin/furan floor 
for new and existing sources.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We are not proposing beyond-the-floor standards for CO/HC for 
dioxin/furan for new solid fuel-fired boilers because we are not 
proposing beyond-the-floor standards for CO/HC and DRE

[[Page 21276]]

for new sources. See discussion in Sections G and H below.
    In addition, we evaluated activated carbon injection or, for 
sources equipped with baghouses, use of catalytically impregnated 
fabric felt/membrane filter materials as beyond-the-floor control for 
further reduction of dioxin/furan emissions to achieve a beyond-the-
floor level of 0.15 ng TEQ/dscm. The incremental annualized compliance 
cost for a new solid fuel-fired boiler with average gas flowrate to 
meet this beyond-the-floor level, rather than comply with the floor 
level, would be approximately $0.28 million and would provide an 
incremental reduction in dioxin/furan emissions of approximately 0.21 
grams TEQ per year, for a cost-effectiveness of $1.3 million per gram 
of dioxin/furan removed. We estimate that this beyond-the-floor option 
would increase the amount of hazardous waste (or solid waste if the 
source retains the Bevill exclusion under 40 CFR 266.112) generated for 
a new solid fuel-fired boiler with average gas flowrate by 270 tons per 
year and would require a source to use an additional 0.1 million kW-
hours per year beyond the requirements to achieve the floor level. 
After considering these impacts and a cost of $1.3 million per gram of 
dioxin/furan removed, we conclude that a beyond-the-floor standard 
based on activated carbon injection or catalytically impregnated fabric 
felt/membrane filter is not warranted for new sources. Consequently, we 
propose a floor standard for dioxin/furan for new sources: Compliance 
with the proposed CO/HC and DRE emissions standards.

B. What Is the Rationale for the Proposed Standards for Mercury?

    The proposed standard for mercury for solid fuel-fired boilers is 
10 [mu]g/dscm for both existing sources and new sources.\128\
---------------------------------------------------------------------------

    \128\ As information, EPA proposed MACT standards for mercury 
for solid fuel-fired industrial, commercial, and institutional 
boilers that do not burn hazardous waste of 5.3 [mu]g/dscm for 
existing sources and 3.4 [mu]g/dscm for new sources. See 68 FR 1660 
(Jan. 13, 2003). These standards are based on use of fabric filters 
to control mercury emissions.
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
    The MACT floor for existing sources is 10 [mu]g/dscm based on 
adsorption of mercury onto coal fly ash and removal of fly ash by the 
electrostatic precipitator or baghouse.
    All solid fuel-fired boilers are equipped with electrostatic 
precipitators or baghouses. We have compliance test emissions data for 
three sources equipped with electrostatic precipitators which document 
maximum mercury emissions ranging from 3 ug/dscm to 11 [mu]g/dscm and 
system removal efficiencies of 83% to 96%. These three sources 
represent seven of the 12 solid fuel-fired boilers.\129\ The Agency has 
also determined that coal-fired utility boilers can achieve significant 
control of mercury by adsorption on fly ash and particulate matter 
control.\130\
---------------------------------------------------------------------------

    \129\ Owners and operators have used the emissions data from the 
three boilers as ``data in lieu of testing'' emissions from other, 
identical boilers at the same facility. One of the three boilers as 
two such sister identical boilers, and the other two boilers each 
have a sister identical boiler. Thus, emissions from these three 
boilers represent emissions from seven of the 12 solid fuel-fired 
boilers.
    \130\ Memo from Frank Princiotta, USEPA, to John Seitz, USEPA, 
entitled ``Control of Mercury Emissions from Coal-fired Utility 
Boilers,'' dated October 25, 2000.
---------------------------------------------------------------------------

    To identify the MACT floor, we evaluated the compliance test 
emissions data using the SRE/Feed Approach. The calculated floor is 10 
[mu]g/dscm, which considers emissions variability. This is an emission 
level that the average of the best performing sources could be expected 
to achieve in 99 of 100 future tests when operating under operating 
conditions identical to the compliance test conditions during which the 
emissions data were obtained. We estimate that this emission level is 
being achieved by 67% of sources and would provide a reduction in 
mercury emissions of 0.015 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified two potential beyond-the-floor techniques for control 
of mercury: (1) Activated carbon injection; and (2) control of mercury 
in the hazardous waste feed. For reasons discussed below, we are not 
proposing a beyond-the-floor standard for mercury.
    a. Use of Activated Carbon Injection. We evaluated activated carbon 
injection as beyond-the-floor control for further reduction of mercury 
emissions. Activated carbon has been demonstrated for controlling 
mercury from waste combustion systems and has achieved efficiencies 
ranging from 80% to greater than 90% depending on factors such as: 
Activated carbon type/impregnation; injection rate; mercury speciation 
in the flue gas; and flue gas temperature. We made a conservative 
assumption that the use of activated carbon will provide 70% mercury 
control for coal-fired boilers given the low mercury levels at the 
floor. Applying this activated carbon removal efficiency to the mercury 
floor level of 10 [mu]g/dscm would provide a beyond-the-floor level of 
3.0 [mu]g/dscm.
    The national incremental annualized compliance cost for solid fuel 
boilers to meet this beyond-the-floor level rather than comply with the 
floor controls would be approximately $1.1 million and would provide an 
incremental reduction in mercury emissions beyond the MACT floor 
controls of 0.03 tons per year. We evaluated nonair quality health and 
environmental impacts and energy effects and estimate that this beyond-
the-floor option would increase the amount of hazardous waste (or solid 
waste if the source retains the Bevill exclusion under 40 CFR 266.112) 
generated by 1,000 tons per year and would require sources to use an 
additional 0.35 million kW-hours per year beyond the requirements to 
achieve the floor level. Based on these factors and costs of 
approximately $35 million per additional ton of mercury removed, we are 
not proposing a beyond-the-floor standard based on activated carbon 
injection.
    b. Feed Control of Mercury in the Hazardous Waste. We also 
evaluated a beyond-the-floor level of 8 [mu]g/dscm, which represents a 
20% reduction from the floor level. The national incremental annualized 
compliance cost for solid fuel boilers to meet this beyond-the-floor 
level rather than comply with the floor controls would be approximately 
$0.11 million and would provide an incremental reduction in mercury 
emissions beyond the MACT floor controls of 0.005 tons per year. Nonair 
quality health and environmental impacts and energy effects are not 
significant factors for feedrate control.
    We are not proposing a beyond-the-floor standard based on feed 
control of mercury in the hazardous waste because it would not be cost-
effective at approximately $23 million per additional ton of mercury 
removed. Consequently, we propose a floor standard for mercury for 
existing sources of 10 [mu]g/dscm.
3. What Is the Rationale for MACT Floor for New Sources?
    MACT floor for new sources would be 10 [mu]g/dscm, the same as the 
floor for existing sources. This is an emission level that the single 
best performing source identified by the SRE/Feed Approach could be 
expected to achieve in 99 of 100 future tests when operating under 
operating conditions identical to the compliance test conditions during 
which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We identified the same two potential beyond-the-floor techniques 
for control

[[Page 21277]]

of mercury: (1) Use of activated carbon injection; and (2) control of 
mercury in the hazardous waste feed.
    We evaluated use of carbon injection for new sources to achieve a 
beyond-the-floor emission level of 5.0 [mu]g/dscm. The incremental 
annualized compliance cost for a new solid fuel boiler with average gas 
flowrate to meet this beyond-the-floor level, rather than comply with 
the floor level, would be approximately $0.28 million and would provide 
an incremental reduction in mercury emissions of approximately 0.008 
tons per year, for a cost-effectiveness of $37 million per ton of 
mercury removed. We estimate that this beyond-the-floor option would 
increase the amount of hazardous waste (or solid waste if the source 
retains the Bevill exclusion under 40 CFR 266.112) generated for a new 
solid fuel-fired boiler with average gas flowrate by 270 tons per year 
and would require a source to use an additional 0.1 million kW-hours 
per year beyond the requirements to achieve the floor level. After 
considering these impacts and, primarily, cost-effectiveness, we are 
not proposing a beyond-the-floor standard based on activated carbon 
injection for new sources. Consequently, we propose a floor standard 
for mercury of 10 [mu]g/dscm for new sources.

C. What Is the Rationale for the Proposed Standards for Particulate 
Matter?

    The proposed standards for particulate matter for solid fuel-fired 
boilers are 69 mg/dscm (0.030 gr/dscf) for existing sources and 34 mg/
dscm (0.015 gr/dscf) for new sources.\131\ The particulate matter 
standard serves as a surrogate for nonmercury HAP metals in emissions 
from the coal burned in the boiler, and for nonenumerated HAP metal 
emissions attributable to the hazardous waste fuel burned in the 
boiler.
---------------------------------------------------------------------------

    \131\ As information, EPA proposed MACT standards for 
particulate matter for solid fuel-fired industrial, commercial, and 
institutional boilers that do not burn hazardous waste of 0.035 gr/
dscf for existing sources and 0.013 gr/dscf for new sources. See 68 
FR 1660 (Jan. 13, 2003). These standards are based on control of 
particulate matter emissions using a fabric filter.
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
    All solid fuel-fired boilers are equipped with electrostatic 
precipitators or baghouses. We have compliance test emissions data for 
seven boilers. Emissions from these seven boilers represent emissions 
from all 12 solid fuel-fired boilers.\132\ Particulate emissions range 
from 0.021 gr/dscf to 0.037 gr/dscf.\133\
---------------------------------------------------------------------------

    \132\ Owners and operators have determined that emissions from 
these seven boilers represent emissions from five other identical, 
sister boilers. Owners and operators have used the emissions from 
these seven boilers as ``data in lieu of testing'' emissions from 
the other five identical boilers.
    \133\ Although particulate matter emissions are predominantly 
attributable to coal ash rather than ash from hazardous waste fuel, 
we did not combine emissions data for coal-fired boilers that do not 
burn hazardous waste with the data for boilers that burn hazardous 
waste because we have particulate emissions data for all boilers 
that burn hazardous waste.
---------------------------------------------------------------------------

    To identify the floor level, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
air pollution control device approach. See discussion in Part Two, 
Section VI.A.2.a. The calculated floor is 140 mg/dscm (0.063 gr/dscf), 
which considers emissions variability. This is an emission level that 
the average of the best performing sources could be expected to achieve 
in 99 of 100 future tests when operating under conditions identical to 
the compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 75% 
of sources. Compliance with the floor level would reduce particulate 
matter emissions by 33 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated improved design, operation, and maintenance of the 
existing electrostatic precipitators (e.g., humidification to improve 
gas conditioning) and baghouses (e.g., improved bags) for these boilers 
to achieve a beyond-the-floor emission level of 69 mg/dscm (0.030 gr/
dscf). We also evaluated a more stringent standard based on adding a 
polishing fabric filter to achieve a beyond-the-floor emission level of 
0.015 gr/dscf. The national incremental annualized compliance cost for 
solid fuel boilers to meet a beyond-the-floor level of 69 mg/dscm 
rather than comply with the floor controls would be approximately $1.3 
million and would provide an incremental reduction in particulate 
matter emissions beyond the MACT floor controls of 400 tons per year 
and an incremental reduction in metal HAP of 6.8 tons per year. We 
evaluated nonair quality health and environmental impacts and energy 
effects and estimate that this beyond-the-floor option would increase 
the amount of hazardous waste (or solid waste if the source retains its 
Bevill exclusion under 40 CFR 266.112) generated by 380 tons per year 
and would require sources to use an additional 3.3 million kW-hours per 
year and to use an additional 160 million gallons of water beyond the 
requirements to achieve the floor level.
    Notwithstanding these nonair quality health and environmental 
impacts and energy effects, a beyond-the-floor standard of 69 mg/dscm 
(0.030 gr/dscf) based on improved particulate matter control is 
warranted because it is cost-effective at a cost of approximately 
$3,200 per additional ton of particulate matter removed and a cost of 
approximately $190,000 per additional ton of metal HAP removed.\134\ In 
addition, the average incremental annualized cost would be only 
$120,000 per facility. We also note that, although section 112(d) only 
authorizes control of HAPs, and particulate matter is not itself a HAP 
but a surrogate for HAP metals, Congress expected the MACT program to 
result in significant emissions reductions of criteria air pollutants 
(of which particulate matter is one), and viewed this as an important 
benefit of the MACT (and residual risk) provisions. See 5 Legislative 
History at 8512 (Senate Committee Report). Finally, we note that this 
beyond-the-floor standard of 0.030 gr/dscf would be comparable to the 
floor-based standard the Agency recently promulgated for solid fuel-
fired boilers that do not burn hazardous waste: 0.07 lb/MM Btu 
(approximately 0.034 gr/dscf). See NESHAP for Industrial/Commercial/
Institutional Boilers and Process Heaters, signed Feb. 26, 2004. 
Because hazardous waste does not contribute substantially to 
particulate matter emissions from coal-fired boilers, MACT standards 
for solid fuel boilers should be similar irrespective of whether they 
burn hazardous waste.
---------------------------------------------------------------------------

    \134\ Note that we are not proposing beyond-the-floor 
particulate matter standards for incinerators, cement kilns, 
lightweight aggregate kilns, and liquid fuel-fired boilers because 
those standards would have a cost-effectiveness of $12,000 to 
$80,000 per ton of particulate matter removed, substantially higher 
than the $3,200 per ton cost-effectiveness of a beyond-the-floor 
standard for solid fuel-fired boilers.
---------------------------------------------------------------------------

    A 34 mg/dscm beyond-the-floor standard for existing sources based 
on use of a polishing fabric filter would remove an additional 570 tons 
per year of particulate matter beyond the floor level at a cost-
effectiveness of $9,800 per ton removed. We conclude that this standard 
would not be as cost-effective as a 69 mg/dscm standard and would 
result in greater nonair quality health and environmental impacts and 
energy effects. For these reasons, we propose a beyond-the-floor 
particulate matter standard of 0.030 gr/dscf (69 mg/dscm) for existing 
sources. We specifically request comment on whether this beyond-the-
floor standard is warranted.

[[Page 21278]]

3. What Is the Rationale for the MACT Floor for New Sources?
    MACT floor for new sources would be 90 mg/dscm (0.040 gr/dscf), 
considering emissions variability. This is an emission level that the 
single best performing source identified by the APCD Approach (i.e., 
the source using a fabric filter with the lowest emissions) could be 
expected to achieve in 99 of 100 future tests when operating under 
operating conditions identical to the compliance test conditions during 
which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated use of a fabric filter to achieve a beyond-the-floor 
emission level of 34 mg/dscm (0.015 gr/dscf). The incremental 
annualized cost for a new solid fuel-fired boiler with average gas 
flowrate to meet this beyond-the-floor level, rather than comply with 
the floor level, would be approximately $280,000 and would provide an 
incremental reduction in particulate emissions of approximately 44 tons 
per year, for a cost-effectiveness of $6,400 per ton of particulate 
matter removed. We estimate that this beyond-the-floor option would 
increase the amount of hazardous waste (or solid waste if the source 
retains the Bevill exclusion under 40 CFR 266.112) generated for a new 
solid fuel-fired boiler with average gas flowrate by 44 tons per year 
and would require a source to use an additional 1.1 million kW-hours 
per year beyond the requirements to achieve the floor level. 
Notwithstanding these impacts, a standard of 34 mg/dscm (0.015 gr/dscf) 
is warranted because it would be cost-effective and it would remove 
additional nonenumerated metal HAP. We also note that this beyond-the-
floor standard of 0.015 gr/dscf for new sources would be comparable to 
the floor-based standard the Agency recently promulgated for new solid 
fuel-fired boilers that do not burn hazardous waste: 0.025 lb/MM Btu 
(approximately 0.012 gr/dscf). See NESHAP for Industrial/Commercial/
Institutional Boilers and Process Heaters, signed Feb. 26, 2004.
    For these reasons, we propose a beyond-the-floor particulate matter 
standard of 34 mg/dscm (0.015 gr/dscf) for new sources. We specifically 
request comment on whether this beyond-the-floor standard is warranted.

D. What Is the Rationale for the Proposed Standards for Semivolatile 
Metals?

    The proposed standard for semivolatile metals (lead and cadmium, 
combined) for solid fuel-fired boilers is 170 [mu]g/dscm for both 
existing and new sources.\135\
---------------------------------------------------------------------------

    \135\ As information, EPA proposed to control nonmercury metal 
HAP emissions for industrial, commercial, and institutional boilers 
that do not burn hazardous waste with a particulate matter emission 
standard only. See 68 FR 1660 (Jan. 13, 2003). For hazardous waste 
combustors, we propose to control specific, enumerated semivolatile 
and low volatile metals with separate emission standards because 
hazardous waste can have a wide range of concentrations of these 
metals, and, thus, particulate matter may contain a wide range of 
metal concentrations. Thus, particulate matter may not be an 
effective surrogate for particular metal HAP. Nonetheless, for 
practical reasons, we rely on particulate matter to control 
nonenumerated metal HAP.
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
    We have compliance test emissions data for four boilers. Emissions 
from these four boilers represent emissions from nine of the 12 solid 
fuel-fired boilers.\136\ Semivolatile metal emissions range from 62 
[mu]g/dscm to 170 [mu]g/dscm. These emissions are expressed as mass of 
semivolatile metals (from all feedstocks) per unit of stack gas.
---------------------------------------------------------------------------

    \136\ Owners and operators have determined that emissions from 
these four boilers represent emissions from five other identical, 
sister boilers. Owners and operators have used the emissions from 
these four boilers as ``data in lieu of testing'' emissions from the 
other five identical boilers.
---------------------------------------------------------------------------

    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 170 [mu]g/dscm, which 
considers emissions variability. This is an emission level that the 
average of the best performing sources could be expected to achieve in 
99 of 100 future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this floor level is being achieved by 42% of 
sources and would reduce semivolatile metals emissions by 0.22 tons per 
year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated three beyond-the-floor approaches for semivolatile 
metals for existing sources: (1) Improved control of particulate 
matter; (2) control of semivolatile metals in the hazardous waste feed; 
and (3) a no-cost standard derived from the beyond-the-floor 
particulate matter standard. For reasons discussed below, we are not 
proposing a beyond-the-floor standard for semivolatile metals.
    a. Improved Particulate Matter Control. Controlling particulate 
matter also controls emissions of semivolatile metals. Consequently, we 
evaluated a beyond-the-floor level of 85 [mu]g/dscm, a 50 percent 
reduction in semivolatile metal emissions, that would be achieved by 
reducing particulate matter emissions. The national incremental 
annualized compliance cost for solid fuel boilers to meet this beyond-
the-floor level rather than comply with the floor controls would be 
approximately $0.29 million and would provide an incremental reduction 
in semivolatile metals emissions beyond the MACT floor controls of 0.29 
tons per year. We evaluated the nonair quality health and environmental 
impacts and energy effects of this beyond-the-floor standard and 
estimate that the amount of hazardous waste generated would increase by 
approximately 133 tons per year, an additional 61 million gallons per 
year of water would be used, and an additional 1.3 million kW-hours per 
year of electricity would be used. Therefore, based on these factors 
and costs of approximately $1 million per additional ton of 
semivolatile metals removed, we are not proposing a beyond-the-floor 
standard based on improved particulate matter control.
    b. Feed Control of Semivolatile Metals in the Hazardous Waste. We 
also evaluated a beyond-the-floor level of 140 [mu]g/dscm based on 
additional control of semivolatile metals in the hazardous waste feed. 
This represents a 20% reduction from the floor level. The national 
incremental annualized compliance cost for solid fuel boilers to meet 
this beyond-the-floor level rather than comply with the floor controls 
would be approximately $36,000 and would provide an incremental 
reduction in semivolatile metals emissions beyond the MACT floor 
controls of 0.046 tons per year. Although nonair quality health and 
environmental impacts and energy effects are not significant factors, 
we are not proposing a beyond-the-floor standard based on feed control 
of semivolatile metals in the hazardous waste because it is not cost-
effective at approximately $0.78 million per additional ton of 
semivolatile metals removed.
    c. No-cost Standard Derived from the Beyond-the-Floor Particulate 
Matter Standard. The beyond-the-floor standard for particulate matter 
would also provide beyond-the-floor control for semivolatile metals if 
sources were to comply with the beyond-the-floor particulate matter 
standard using improved particulate matter control

[[Page 21279]]

rather than by reducing the feedrate of ash. To identify a beyond-the-
floor emission level for semivolatile metals that would derive from the 
beyond-the-floor particulate matter standard, we assumed that emissions 
of semivolatile metals would be reduced by the same percentage that 
sources would need to reduce particulate matter emissions. We then 
developed a revised semivolatile metal emission data base considering 
these particulate matter standard-derived reductions and reductions 
needed to meet the semivolatile metal floor level. We analyzed these 
revised emissions to identify the best performing sources and an 
emission level that the average of the best performers could achieve 99 
out of 100 future tests. This emission level--82 [mu]g/dscm--is a 
beyond-the-floor semivolatile metal standard that can be achieved at no 
cost because the costs have been allocated to the particulate matter 
beyond-the-floor standard.
    We are concerned, however, that sources may choose to comply with 
the beyond-the-floor particulate matter standard by controlling the 
feedrate of ash in the hazardous waste feed, which may or may not 
reduce the feedrate and emissions of metal HAP. If so, it would be 
inappropriate to consider the beyond-the-floor standard for 
semivolatile metals discussed above as a no-cost standard. We 
specifically request comment on whether sources may comply with beyond-
the-floor particulate matter standard by controlling the feedrate of 
ash.
    For these reasons, we propose a floor standard for semivolatile 
metals of 170 [mu]g/dscm for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
    MACT floor for new sources would be 170 [mu]g/dscm, considering 
emissions variability. This is the same as the floor for existing 
sources. This is an emission level that the single best performing 
source identified by the SRE/Feed Approach could be expected to achieve 
in 99 of 100 future tests when operating under operating conditions 
identical to the compliance test conditions during which the emissions 
data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated three beyond-the-floor approaches for semivolatile 
metals for new sources: (1) Improved particulate matter controls; (2) 
control of semivolatile metals in the hazardous waste feed; and (3) a 
no-cost standard derived from the beyond-the-floor particulate matter 
standard.
    a. Improved Particulate Matter Controls. We evaluated improved 
control of particulate matter using a fabric filter as beyond-the-floor 
control for further reductions in semivolatile metals emissions. We 
evaluated a beyond-the-floor level of 71 [mu]g/dscm. The incremental 
annualized compliance cost for a new solid fuel boiler with average gas 
flowrate to meet this beyond-the-floor level, rather than comply with 
the floor level, would be approximately $0.28 million and would provide 
an incremental reduction in semivolatile metals emissions of 
approximately 0.15 tons per year, for a cost-effectiveness of $1.8 
million per ton of semivolatile metals removed. We estimate that this 
beyond-the-floor option would increase the amount of hazardous waste 
(or solid waste if the source retains the Bevill exclusion under 40 CFR 
266.112) generated for a new solid fuel-fired boiler with average gas 
flowrate by 44 tons per year and would require the source to use an 
additional 1.2 million kW-hours per year beyond the requirements to 
achieve the floor level. After considering these impacts and cost-
effectiveness, we conclude that a beyond-the-floor standard for new 
sources based on use of a fabric filter to improve control of 
particulate matter is not warranted.
    b. Feedrate Control. For similar reasons discussed above for 
existing sources, we conclude that a beyond-the-floor standard based on 
controlling the semivolatile metals in the hazardous waste feed would 
not be cost-effective.
    c. No-cost Standard Derived from the Beyond-the-Floor Particulate 
Matter Standard. As discussed above in the context of existing sources, 
the beyond-the-floor standard for particulate matter would also provide 
beyond-the-floor control for semivolatile metals if sources were to 
comply with the beyond-the-floor particulate matter standard using 
improved particulate matter control rather than by reducing the 
feedrate of ash. Under this approach, the no-cost beyond-the-floor 
standard for semivolatile metals for new sources would be 44 [mu]g/
dscm. As discussed above, however, we are concerned that sources may 
choose to comply with the beyond-the-floor particulate matter standard 
by controlling the feedrate of ash in the hazardous waste feed, which 
may or may not reduce the feedrate and emissions of metal HAP. If so, 
it would be inappropriate to consider this beyond-the-floor standard as 
a no-cost standard. We specifically request comment on whether sources 
may comply with beyond-the-floor particulate matter standard by 
controlling the feedrate of ash.
    For these reasons, we propose a semivolatile metals standard of 170 
[mu]g/dscm for new sources.

E. What Is the Rationale for the Proposed Standards for Low Volatile 
Metals?

    The proposed standards for low volatile metals (arsenic, beryllium, 
and chromium) for solid fuel-fired boilers is 210 [mu]g/dscm for 
existing sources and 190 [mu]g/dscm for new sources.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    We have compliance test emissions data for four boilers. Emissions 
from these four boilers represent emissions from 10 of the 12 solid 
fuel-fired boilers.\137\ Low volatile metal emissions range from 41 
[mu]g/dscm to 230 [mu]g/dscm. These emissions are expressed as mass of 
low volatile metals (from all feedstocks) per unit of stack gas.
---------------------------------------------------------------------------

    \137\ Owners and operators have determined that emissions from 
these four boilers represent emissions from five other identical, 
sister boilers. Owners and operators have used the emissions from 
these four boilers as ``data in lieu of testing'' emissions from the 
other five identical boilers.
---------------------------------------------------------------------------

    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 210 [mu]g/dscm, which 
considers emissions variability. This is an emission level that the 
average of the best performing sources could be expected to achieve in 
99 of 100 future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 67% 
of sources and that it would reduce low volatile metals emissions by 
0.45 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated three beyond-the-floor approaches for low volatile 
metals for existing sources: (1) Improved control of particulate 
matter; (2) control of low volatile metals in the hazardous waste feed; 
and (3) a no-cost standard derived from the beyond-the-floor 
particulate matter standard. For reasons discussed below, we are not 
proposing a beyond-the-floor standard for low volatile metals.
    a. Improved Particulate Matter Control. Controlling particulate 
matter also controls emissions of low volatile metals. We evaluated a 
beyond-the-floor level of 105 [mu]g/dscm. The national incremental 
annualized compliance cost for solid fuel boilers to meet this

[[Page 21280]]

beyond-the-floor level rather than comply with the floor controls would 
be approximately $0.32 million and would provide an incremental 
reduction in low volatile metals emissions beyond the MACT floor 
controls of 0.37 tons per year. We evaluated the nonair quality health 
and environmental impacts and energy effects of this beyond-the-floor 
standard and estimate that the amount of hazardous waste generated 
would increase by approximately 83 tons per year, an additional 54 
million gallons of water per year would be used, and electricity 
consumption would increase by 1.2 million kW-hours per year. 
Considering these impacts and a cost of approximately $0.87 million per 
additional ton of low volatile metals removed, we are not proposing a 
beyond-the-floor standard based on improved particulate matter control.
    b. Feed Control of Low Volatile Metals in the Hazardous Waste. We 
also evaluated a beyond-the-floor level of 170 [mu]g/dscm, which 
represents a 20% reduction from the floor level. The national 
incremental annualized compliance cost for solid fuel boilers to meet 
this beyond-the-floor level rather than comply with the floor controls 
would be approximately $98,000 and would provide an incremental 
reduction in low volatile metals emissions beyond the MACT floor 
controls of 0.13 tons per year. Although nonair quality health and 
environmental impacts and energy effects are not significant factors, 
we are not proposing a beyond-the-floor standard based on feedrate 
control of low volatile metals in the hazardous waste because it would 
not be cost-effective at approximately $0.78 million per additional ton 
of low volatile metals removed.
    c. No-cost Standard Derived from the Beyond-the-Floor Particulate 
Matter Standard. As discussed above in the context of semivolatile 
metals, the beyond-the-floor standard for particulate matter would also 
provide beyond-the-floor control for low volatile metals if sources 
were to comply with the beyond-the-floor particulate matter standard 
using improved particulate matter control rather than by reducing the 
feedrate of ash. To identify a beyond-the-floor emission level for low 
volatile metals that would derive from the beyond-the-floor particulate 
matter standard, we assumed that emissions of low volatile metals would 
be reduced by the same percentage that sources would need to reduce 
particulate matter emissions. We then developed a revised low volatile 
metal emission data base considering these particulate matter standard-
derived reductions and reductions needed to meet the low volatile metal 
floor level. We analyzed these revised emissions to identify the best 
performing sources and an emission level that the average of the best 
performers could achieve 99 out of 100 future tests. This emission 
level--110 [mu]g/dscm--is a beyond-the-floor low volatile metal 
standard that can be achieved at no cost because the costs have been 
allocated to the particulate matter beyond-the-floor standard.
    We are concerned, however, that sources may choose to comply with 
the beyond-the-floor particulate matter standard by controlling the 
feedrate of ash in the hazardous waste feed, which may or may not 
reduce the feedrate and emissions of metal HAP. If so, it would be 
inappropriate to consider the beyond-the-floor standard for low 
volatile metals discussed above as a no-cost standard. We specifically 
request comment on whether sources may comply with beyond-the-floor 
particulate matter standard by controlling the feedrate of ash.
    For these reasons, we propose a floor standard for low volatile 
metals of 210 [mu]g/dscm for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
    MACT floor for low volatile metals for new sources would be 190 
[mu]g/dscm, considering emissions variability. This is an emission 
level that the single best performing source identified by the SRE/Feed 
Approach could be expected to achieve in 99 of 100 future tests when 
operating under operating conditions identical to the compliance test 
conditions during which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated three beyond-the-floor approaches for low volatile 
metals for new sources: (1) Improved particulate matter control; (2) 
control of low volatile metals in the hazardous waste feed; and (3) a 
no-cost standard derived from the beyond-the-floor particulate matter 
standard.
    a. Improved Particulate Matter Control. We evaluated improved 
control of particulate matter using a fabric filter to achieve an 
emission level of 79 [mu]g/dscm as beyond-the-floor control for low 
volatile metals emissions. The incremental annualized compliance cost 
for a new solid fuel boiler to meet this beyond-the-floor level, rather 
than comply with the floor level, would be approximately $0.28 million 
and would provide an incremental reduction in low volatile metals 
emissions of approximately 0.17 tons per year, for a cost-effectiveness 
of $1.7 million per ton of low volatile metals removed. We estimate 
that this beyond-the-floor option would increase the amount of 
hazardous waste (or solid waste if the source retains the Bevill 
exclusion under 40 CFR 266.112) generated for a new solid fuel-fired 
boiler with average gas flowrate by 44 tons per year and would require 
the source to use an additional 1.2 million kW-hours per year beyond 
the requirements to achieve the floor level. After considering these 
impacts and cost-effectiveness, we conclude that a beyond-the-floor 
standard based on improved particulate matter control using a fabric 
filter for new sources is not warranted.
    b. Feedrate Control. For similar reasons discussed above for 
existing sources, we conclude that a beyond-the-floor standard based on 
controlling the low volatile metals in the hazardous waste feed would 
not be cost-effective.
    c. No-cost Standard Derived from the Beyond-the-Floor Particulate 
Matter Standard. As discussed above in the context of existing sources, 
the beyond-the-floor standard for particulate matter would also provide 
beyond-the-floor control for low volatile metals if sources were to 
comply with the beyond-the-floor particulate matter standard using 
improved particulate matter control rather than by reducing the 
feedrate of ash. Under this approach, the no-cost beyond-the-floor 
standard for low volatile metals for new sources would be 34 [mu]g/
dscm. As discussed above, however, we are concerned that sources may 
choose to comply with the beyond-the-floor particulate matter standard 
by controlling the feedrate of ash in the hazardous waste feed, which 
may or may not reduce the feedrate and emissions of metal HAP. If so, 
it would be inappropriate to consider this beyond-the-floor standard as 
a no-cost standard. We specifically request comment on whether sources 
may comply with beyond-the-floor particulate matter standard by 
controlling the feedrate of ash.
    For these reasons, we propose a low volatile metals standard of 190 
[mu]g/dscm for new sources.

F. What Is the Rationale for the Proposed Standards for Total Chlorine?

    The proposed standards for hydrogen chloride and chlorine gas 
(i.e., total chlorine, reported as a hydrogen chloride equivalents) for 
solid fuel-fired boilers are 440 ppmv for existing sources and 73 ppmv 
for new sources.\138\
---------------------------------------------------------------------------

    \138\ As information, EPA proposed MACT standards for hydrogen 
chloride for solid fuel-fired industrial, commercial, and 
institutional boilers that do not burn hazardous waste of 68 ppmv 
for existing sources and 15 ppmv for new sources. See 68 FR 1660 
(Jan. 13, 2003). These standards are based on use of wet scrubbers 
to control hydrogen chloride.

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[[Page 21281]]

1. What Is the Rationale for the MACT Floor for Existing Sources?
    Solid fuel-fired boilers that burn hazardous waste are equipped 
with electrostatic precipitators or baghouses and do not have back-end 
controls for total chlorine. Total chlorine emissions are controlled by 
controlling the feedrate of chlorine in the hazardous waste feed. We 
have compliance test emissions data for five boilers. Emissions from 
these five boilers represent emissions from 10 of the 12 solid fuel-
fired boilers.\139\ Total chlorine emissions range from 60 ppmv to 700 
ppmv.
---------------------------------------------------------------------------

    \139\ Owners and operators have determined that emissions from 
these five boilers represent emissions from five other identical, 
sister boilers. Owners and operators have used the emissions from 
these five boilers as ``data in lieu of testing'' emissions from the 
other five identical boilers.
---------------------------------------------------------------------------

    To identify the MACT floor, we evaluated the compliance test 
emissions data associated with the most recent test campaign using the 
SRE/Feed Approach. The calculated floor is 440 ppmv, which considers 
emissions variability. This is an emission level that the best 
performing feed control sources could be expected to achieve in 99 of 
100 future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this emission level is being achieved by 83% 
of sources and that it would reduce total chlorine emissions by 420 
tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated dry scrubbing to achieve a beyond-the-floor emission 
level of 110 ppmv for total chlorine for existing sources, assuming 
conservatively a 75% removal efficiency. The national annualized 
incremental compliance cost for solid fuel-fired boilers to comply with 
this beyond-the-floor level rather than the floor level would be $3.7 
million, and emissions of total chlorine would be reduced by an 
additional 790 tons per year, for a cost-effectiveness of $4,700 per 
ton of total chlorine removed. We evaluated the nonair quality health 
and environmental impacts and energy effects of this beyond-the-floor 
level and estimate that the amount of hazardous waste generated would 
increase by 18,000 tons per year, an additional 27 million gallons of 
water per year would be used, and electricity consumption would 
increase by 0.11 million kW-hours per year.
    We note that a cost of $4,700 per additional ton of total chlorine 
removed is in the ``grey area'' between a cost the Agency has concluded 
is cost-effective and a cost the Agency has concluded is not cost-
effective under other MACT rules. EPA concluded that a cost of $1,100 
per ton of total chlorine removed for hazardous waste burning 
lightweight aggregate kilns was cost-effective in the 1999 MACT final 
rule. See 68 FR at 52900. EPA concluded, however, that a cost of 
$45,000 per ton of hydrogen chloride removed was not cost-effective for 
industrial boilers. See 68 FR at 1677.
    Although a beyond-the-floor standard of 110 ppmv for solid fuel 
boilers under today's rule would provide health benefits from 
collateral reductions in SO2 emissions,\140\ we are 
concerned that a cost of $4,700 per additional ton of total chlorine 
removed is not warranted. Therefore, after considering cost-
effectiveness and nonair quality health and environmental impacts and 
energy effects, we are not proposing a beyond-the-floor standard based 
on dry scrubbing. We specifically request comment on whether a beyond-
the-floor standard is warranted.
---------------------------------------------------------------------------

    \140\ See U.S. EPA, ``Addendum to the Assessment of the 
Potential Costs, Benefits, and Other Impacts of the Hazardous Waste 
Combustion MACT Replacement Standards--Proposed Rule,'' March 2004.
---------------------------------------------------------------------------

    We also evaluated use of feedrate control of chlorine in hazardous 
waste to achieve a beyond-the-floor level of 350 ppmv, which represents 
a 20% reduction from the floor level. The national annualized 
incremental compliance cost for solid fuel-fired boilers to comply with 
this beyond-the-floor level rather than the floor level would be $0.08 
million, and emissions of total chlorine would be reduced by an 
additional 40 tons per year, for a cost-effectiveness of $2,000 per ton 
of total chlorine removed. Although nonair quality health and 
environmental impacts and energy effects are not significant factors 
for feedrate control, we are not proposing a beyond-the-floor standard 
based on hazardous waste feedrate control because we are concerned 
about the practicability of achieving these emissions reductions, and 
our estimate of the associated cost, using feedrate control. We 
specifically request comment on use of feedrate control of chlorine in 
hazardous waste as a beyond-the-floor control technique, the emission 
reductions that could be achieved, and the costs of achieving those 
reductions.
3. What Is the Rationale for the MACT Floor for New Sources?
    MACT floor for new sources would be 73 ppmv. This is an emission 
level that the single best performing source identified by the 
Emissions Approach (i.e., the source with the lowest emissions) could 
be expected to achieve in 99 of 100 future tests when operating under 
operating conditions identical to the compliance test conditions during 
which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated dry lime scrubbing to achieve a beyond-the-floor 
emission level of 37 ppmv for total chlorine for new sources, assuming 
conservatively a 50% removal efficiency.\141\ The incremental 
annualized compliance cost for a new solid fuel boiler with average gas 
flowrate to meet this beyond-the-floor level, rather than comply with 
the floor level, would be approximately $610,000 and would provide an 
incremental reduction in total chlorine emissions of approximately 42 
tons per year. Although nonair quality health and environmental impacts 
and energy effects are not significant factors, we conclude that a 
beyond-the-floor standard of 37 ppmv is not warranted because it would 
not be cost-effective at approximately $14,000 per additional ton of 
total chlorine removed.
---------------------------------------------------------------------------

    \141\ Although we assumed dry scrubbing can readily achieve 75% 
removal of total chlorine for beyond-the-floor control for existing 
sources, assuming 50% removal for beyond-the-floor control for new 
sources is appropriate. This is because the floor for new sources--
73 ppmv--is substantially lower than the floor for existing 
sources--440 ppmv--and dry scrubbing is less efficient at lower 
uncontrolled emission levels.
---------------------------------------------------------------------------

    For these reasons, we propose a floor standard for total chlorine 
of 73 ppmv for new sources.

G. What Is the Rationale for the Proposed Standards for Carbon Monoxide 
or Hydrocarbons?

    To control emissions of organic HAP, existing and new sources would 
be required to comply with either a carbon monoxide standard of 100 
ppmv or a hydrocarbon standard of 10 ppmv.\142\
---------------------------------------------------------------------------

    \142\ As information, EPA proposed MACT standards for carbon 
monoxide for new solid fuel-fired industrial, commercial, and 
institutional boilers that do not burn hazardous waste of 400 ppmv 
corrected to 3% oxygen. See 68 FR 1660 (Jan. 13, 2003).
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
    Solid fuel-fired boilers that burn hazardous waste are currently 
subject to RCRA standards that require

[[Page 21282]]

compliance with either a carbon monoxide standard of 100 ppmv, or a 
hydrocarbon standard of 20 ppmv. Compliance is based on an hourly 
rolling average as measured with a CEMS. See Sec.  266.104(a). We are 
proposing today floor standards of 100 ppmv for carbon monoxide or 10 
ppmv for hydrocarbons.
    Floor control for existing sources is operating under good 
combustion practices including: (1) Providing adequate excess air with 
use of oxygen CEMS and feedback air input control; (2) providing 
adequate fuel/air mixing; (3) homogenizing hazardous waste fuels (such 
as by blending or size reduction) to control combustion upsets due to 
very high or very low volatile content wastes; (4) regulating waste and 
air feedrates to ensure proper combustion temperature and residence 
time; (5) characterizing waste prior to burning for combustion-related 
composition (including parameters such as heating value, volatile 
content, liquid waste viscosity, etc.); (6) ensuring the source is 
operated by qualified, experienced operators; and (7) periodic 
inspection and maintenance of combustion system components such as 
burners, fuel and air supply lines, injection nozzles, etc. Given that 
there are many interdependent parameters that affect combustion 
efficiency and thus carbon monoxide and hydrocarbon emissions, we are 
not able to quantify ``good combustion practices.''
    Ten of 12 solid fuel-fired boilers are currently complying with the 
RCRA carbon monoxide limit of 100 ppmv on an hourly rolling average. 
The remaining two boilers are complying with the RCRA hydrocarbon limit 
of 20 ppmv on an hourly rolling average. Those boilers have hydrocarbon 
levels below 5 ppmv, however, indicative of operating under good 
combustion practices.
    We propose a floor level for carbon monoxide level of 100 ppmv 
because it is a currently enforceable Federal standard. Although the 
best performing sources are achieving carbon monoxide levels below 100 
ppmv, it is not appropriate to establish a lower floor level because 
carbon monoxide is a surrogate for nondioxin/furan organic HAP. As 
such, lowering the carbon monoxide floor may not significantly reduce 
organic HAP emissions. In addition, it would be inappropriate to apply 
a MACT methodology to the carbon monoxide emissions from the best 
performing sources because those sources may not be able to replicate 
their emission levels. This is because there are myriad factors that 
affect combustion efficiency and, subsequently, carbon monoxide 
emissions. Extremely low carbon monoxide emissions cannot be assured by 
controlling only one or two operating parameters We note also that we 
used this rationale to establish a carbon monoxide standard of 100 ppmv 
for Phase I sources in the September 1999 Final Rule.
    We propose a floor level for hydrocarbons of 10 ppmv even though 
the currently enforceable standard is 20 ppmv because: (1) The two 
sources that comply with the RCRA hydrocarbon standard can readily 
achieve 10 ppmv; and (2) reducing hydrocarbon emissions within the 
range of 20 ppmv to 10 ppmv should reduce emissions of nondioxin/furan 
organic HAP. We do not apply a prescriptive MACT methodology to 
establish a hydrocarbon floor below 10 ppmv, however, because we have 
data from only two sources. In addition, we note that the hydrocarbon 
emission standard for Phase I sources established in the September 1999 
Final Rule is 10 ppmv also.
    There would be no incremental emission reductions associated with 
these floors because all sources are currently achieving the floor 
levels.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We considered beyond-the-floor levels for carbon monoxide and 
hydrocarbons based on use of better combustion practices but conclude 
that they may not be replicable by the best performing sources nor 
duplicable by other sources given that we cannot quantify good 
combustion practices. Moreover, we cannot ensure that carbon monoxide 
or hydrocarbon levels lower than the floors would significantly reduce 
emissions of nondioxin/furan organic HAP. This is because the portion 
of hydrocarbons that is comprised of nondioxin/furan organic HAP is 
likely to become lower as combustion efficiency improves and 
hydrocarbon levels decrease. Thus, at beyond-the-floor hydrocarbon 
levels, we would expect a larger portion of residual hydrocarbons to be 
compounds that are not organic HAP.
    Nonair quality health and environmental impacts and energy 
requirements are not significant factors for use of better combustion 
practices as beyond-the-floor control.
    For these reasons, we conclude that beyond-the-floor standards for 
carbon monoxide and hydrocarbons are not warranted for existing 
sources.
3. What Is the Rationale for the MACT Floor for New Sources?
    MACT floor for new sources would be the same as the floor for 
existing sources--100 ppmv for carbon monoxide and 10 ppmv for 
hydrocarbons--and based on the same rationale.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    As discussed in the context of beyond-the-floor considerations for 
existing sources, we considered beyond-the-floor standards for carbon 
monoxide and hydrocarbons for new sources based on use of better 
combustion practices. But, we conclude that beyond the floor standards 
may not be replicable by the best performing sources nor duplicable by 
other sources given that we cannot quantify good combustion practices. 
Moreover, we cannot ensure that carbon monoxide or hydrocarbon levels 
lower than the floors would significantly reduce emissions of 
nondioxin/furan organic HAP.
    Nonair quality health and environmental impacts and energy 
requirements are not significant factors for use of better combustion 
practices as beyond-the-floor control.
    For these reasons, we conclude that beyond-the-floor standards for 
carbon monoxide and hydrocarbons are not warranted for new sources.

H. What Is the Rationale for the Proposed Standard for Destruction and 
Removal Efficiency?

    To control emissions of organic HAP, existing and new sources would 
be required to comply with a destruction and removal efficiency (DRE) 
of 99.99% for organic HAP. For sources burning hazardous wastes F020, 
F021, F022, F023, F026, or F027, however, the DRE standard is 99.9999% 
for organic HAP.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Solid fuel-fired boilers that burn hazardous waste are currently 
subject to RCRA DRE standards that require 99.99% destruction of 
designated principal organic hazardous constituents (POHCs). For 
sources that burn hazardous wastes F020, F021, F022, F023, F026, or 
F027, however, the DRE standard is 99.9999% destruction of designated 
POHCs. See Sec.  266.104(a).
    The DRE standard helps ensure that a combustor is operating under 
good combustion practices and thus minimizing emissions of organic HAP. 
Under the MACT compliance regime, sources would designate POHCs that 
are organic HAP or that are surrogates for organic HAP.

[[Page 21283]]

    We propose to establish the RCRA DRE standard as the floor for 
existing sources because it is a currently enforceable Federal 
standard. There would be no incremental emission reductions associated 
with this floor because sources are currently complying with the 
standard.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We considered a beyond-the-floor level for DRE based on use of 
better combustion practices but conclude that it may not be replicable 
by the best performing sources nor duplicable by other sources given 
that we cannot quantify better combustion practices. Moreover, we 
cannot ensure that a higher DRE standard would significantly reduce 
emissions of organic HAP given that DRE measures the destruction of 
organic HAP present in the boiler feed rather than gross emissions of 
organic HAP. Although a source's combustion practices may be adequate 
to destroy particular organic HAP in the feed, other organic HAP that 
may be emitted as products of incomplete combustion may not be 
controlled by the DRE standard.\143\
---------------------------------------------------------------------------

    \143\ The carbon monoxide/hydrocarbon emission standard would 
control organic HAP that are products of incomplete combustion by 
also ensuring use of good combustion practices.
---------------------------------------------------------------------------

    For these reasons, and after considering non-air quality health and 
environmental impacts and energy requirements, we are not proposing a 
beyond-the-floor DRE standard for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
    We propose to establish the RCRA DRE standard as the floor for new 
sources because it is a currently enforceable Federal standard.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    Using the same rationale as we used to consider a beyond-the-floor 
DRE standard for existing sources, we conclude that a beyond-the-floor 
DRE standard for new sources is not warranted. Consequently, after 
considering non-air quality health and environmental impacts and energy 
requirements, we are proposing the floor DRE standard for new sources.

XI. How Did EPA Determine the Proposed Emission Standards for Hazardous 
Waste Burning Liquid Fuel-Fired Boilers?

    The proposed standards for existing and new liquid fuel-fired 
boilers that burn hazardous waste are summarized in the table below. 
See proposed Sec.  63.1217.

 
    Proposed Standards for Existing and New Liquid Fuel-Fired Boilers
------------------------------------------------------------------------
                                           Emission standard \1\
   Hazardous air pollutant or    ---------------------------------------
            surrogate              Existing sources       New sources
------------------------------------------------------------------------
Dioxin and furan: sources         0.40 ng TEQ/dscm..  0.015 ng TEQ/dscm
 equipped with dry air pollution                       or control of
 control system \2\.                                   flue gas
                                                       temperature not
                                                       to exceed
                                                       400[deg]F at the
                                                       inlet to the
                                                       particulate
                                                       matter control
                                                       device.
Dioxin and furan: sources         100 ppmv carbon     100 ppmv carbon
 equipped with wet or with no      monoxide or 10      monoxide or 10
 air pollution control systems     ppmv hydrocarbons.  ppmv hydrocarbons
 \2\.
Mercury \3\.....................  3.7E-6 lbs/MM Btu.  3.8E-7 lbs/MM BTU
Particulate matter..............  72 mg/dscm (0.032   17 mg/dscm (0.0076
                                   gr/dscf).           gr/dscf)
Semivolatile metals \3\.........  1.1E-5 lbs/MM BTU.  4.3E-6 lbs/MM BTU
Low volatile metals: chromium     1.1E-4 lbs/MM BTU.  3.6E-5 lbs/MM BTU
 only 3, 4.
Hydrogen chloride and chlorine    2.5E-2 lbs/MM BTU   7.2E-4 lbs/MM BTU
 gas3, 5.                          or the              or the chlorine
                                   alternative         alternative
                                   emission limits     emission limits
                                   under Sec.          under Sec.
                                   63.1215.            63.1215
Carbon monoxide or hydrocarbons   100 ppmv carbon     100 ppmv carbon
 \6\.                              monoxide or 10      monoxide or 10
                                   ppmv                ppmv
                                   hydrocarbons..      hydrocarbons.
Destruction and Removal           For existing and new sources, 99.99%
 Efficiency.                       for each principal organic hazardous
                                   constituent (POHC). For sources
                                   burning hazardous wastes F020, F021,
                                   F022, F023, F026, or F027, however,
                                   99.9999% for each POHC.
------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen, dry basis.
\2\ A wet air pollution system followed by a dry air pollution control
  system is not considered to be a dry air pollution control system for
  purposes of this standard. A dry air pollution systems followed a wet
  air pollution control system is considered to be a dry air pollution
  control system for purposes of this standard.
\3\ Standards are expressed as mass of pollutant emissions contributed
  by hazardous waste per million Btu contributed by the hazardous waste.
 
\4\ Standard is for chromium only and does not include arsenic and
  beryllium.
\5\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\6\ Hourly rolling average. Hydrocarbons reported as propane.

    We considered whether fuel switching could be considered a MACT 
floor control technology for liquid fuel-fired boilers to achieve lower 
HAP emissions. We conclude that HAP emissions from liquid fuel-fired 
boilers are attributable primarily to the hazardous waste fuels rather 
than the natural gas or fuel oil that these boilers burn. Consequently, 
we conclude that fuel switching is not an effective MACT floor control 
technology to reduce HAP emissions for liquid fuel-fired boilers.

A. What Are the Proposed Standards for Dioxin and Furan?

    We propose to establish a dioxin/furan standard for existing liquid 
fuel-fired boilers equipped with dry air pollution control devices of 
0.40 ng TEQ/dscm. The standard for new sources would be 0.015 ng TEQ/
dscm or control of flue gas temperature not to exceed 400 [deg]F at the 
inlet to the particulate matter control device. For liquid fuel-fired 
boilers equipped either with wet air pollution control systems or with 
no air pollution systems, we propose a standard for both existing and 
new sources as compliance with the proposed standards for carbon 
monoxide/hydrocarbon and destruction and removal efficiency. In 
addition, we note that we propose to require a one-time dioxin/furan 
emission test for

[[Page 21284]]

sources that would not be subject to a numerical dioxin/furan emission 
standard, including liquid fuel-fired boilers with wet or no emission 
control device, and new liquid fuel-fired boilers equipped with a dry 
air pollution control device. As discussed in Part Two, Section XIV.B 
below, the testing would assist in developing both section 112(d)(6) 
standards and section 112(f) residual risk standards.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    As discussed in Part Two, Section I.B.5, we used a statistical 
analysis to conclude that liquid boilers equipped with dry air 
pollution control devices have different dioxin/furan emission 
characteristics compared to sources with either wet air pollution 
control or no air pollution control devices.\144\ Note that we consider 
the type of emission control device as a basis for subcategorization 
because the type of control device affects formation of dioxin/furan: 
dioxin/furan can form in dry particulate matter control devices while 
it cannot form in wet (or no) control devices. We therefore believe 
subcategorization is warranted and we propose to identify separate 
floor levels for sources equipped with dry particulate matter control 
devices versus sources with wet or no emission control device.
---------------------------------------------------------------------------

    \144\ Sources with a wet air pollution system followed by a dry 
air pollution control system is not considered to be a dry air 
pollution control system for purposes of this standard. Sources with 
a dry air pollution systems followed a wet air pollution control 
system is considered to be a dry air pollution control system for 
purposes of this standard.
---------------------------------------------------------------------------

    a. MACT Floor for Boilers Equipped with Dry Control Systems. To 
identify the floor level for liquid fuel boilers equipped with dry air 
pollution control systems, we considered whether dioxin/furan can be 
controlled by controlling the temperature at the inlet to the 
particulate matter control device. We conclude that this control 
mechanism may not be the predominant factor that affects dioxin/furan 
emissions from these sources. We have emissions data for three boilers 
equipped with electrostatic precipitators or fabric filters. Emissions 
from two of the boilers are below 0.03 ng TEQ/dscm. We do not have data 
on the gas temperature at the inlet to the emission control device for 
these sources. The third boiler, however, has dioxin/furan emissions of 
2.4 ng TEQ/dscm when the flue gas temperature at the inlet to the 
fabric filter is 410 [deg]F. We conclude from this information that 
this boiler is not likely to be able to achieve dioxin/furan emissions 
below 0.40 ng TEQ/dscm if the gas temperature is reduced to below 400 
[deg]F. This is contrary to the finding we made for cement kilns and 
incinerators without heat recovery boilers and equipped with dry 
particulate matter control devices. In those cases, we conclude that 
gas temperature control at the dry particulate matter control device is 
the predominant factor affecting dioxin/furan emissions. See 
discussions in Sections VII and VIII above. Consequently, other factors 
are likely contributing to high dioxin/furan emissions from the liquid 
fuel-fired boiler equipped with a fabric filter operated at a gas 
temperature of 410 [deg]F, such as metals in the waste feed or soot on 
boiler tubes that may catalyze dioxin/furan formation reactions.
    We evaluated the compliance test emissions data using the Emissions 
Approach and calculated a numerical dioxin/furan floor level of 3.0 ng 
TEQ/dscm, which considers emissions variability. As discussed above, 
however, one of the three sources for which we have emissions data is 
not likely to be able to achieve this emission level using gas 
temperature control at the inlet to the dry particulate matter control 
device. Consequently, we propose to identify the floor level as 3.0 ng 
TEQ/dscm or control of flue gas temperature not to exceed 400 [deg]F at 
the inlet to the particulate matter control device. This floor level is 
duplicable by all sources, and would minimize dioxin/furan emissions 
for sources where flue gas temperature at the control device 
substantially affects dioxin/furan emissions. We estimate that this 
emission level is being achieved by all sources and, thus, would not 
reduce dioxin/furan emissions.
    b. MACT Floor for Boilers Equipped with Wet or No Control Systems. 
We have dioxin/furan emissions data for 33 liquid fuel-fired boilers 
equipped with a wet or no particulate matter control device. Emissions 
levels are below 0.1 ng TEQ/dscm for 30 of the sources. Emission levels 
for the other three sources are 0.19, 0.36, and 0.44 ng TEQ/dscm.
    As previously discussed in Part Two, Section VII.A, we believe that 
it would be inappropriate to establish a numerical dioxin/furan 
emission floor level for sources using wet or no air pollution control 
systems based on the emissions achieved by the best performing sources 
because a numerical floor level would not be replicable by the best 
performing sources nor duplicable by other sources. As a result, we 
propose to define the MACT floor for sources with wet or no emission 
control devices as operating under good combustion practices by 
complying with the destruction and removal efficiency and carbon 
monoxide/hydrocarbon standards.\145\ There would be no emissions 
reductions for these existing boilers to comply with the floor level 
because they are currently complying with the carbon monoxide/
hydrocarbon standard and destruction and removal efficiency standard 
pursuant to RCRA requirements.
---------------------------------------------------------------------------

    \145\ The fact that we determined floor control for existing 
sources as good combustion practices does not mean that all sources 
using floor control will have low dioxin/furan emissions. As 
discussed in Part Two, Section XIV.B., we are proposing to require 
liquid fuel-fired boilers that would not be subject to a numerical 
dioxin/furan emission standard to perform a one-time dioxin/furan 
emissions test to quantify the effectiveness of today's proposed 
surrogate for dioxin/furan emission control.
---------------------------------------------------------------------------

    We also request comment on an alternative MACT floor expressed as a 
dioxin/furan emission concentration for liquid fuel boilers with wet or 
no emission control devices.\146\ Although it would be inappropriate to 
identify a floor concentration based on the average emissions of the 
best performing sources as discussed above, we possibly could identify 
the floor as the highest emission concentration from any source in our 
data base, after considering emissions variability.
---------------------------------------------------------------------------

    \146\ Although the floor for liquid fuel boilers equipped with a 
dry emission control device would not be a numerical standard (i.e., 
3.0 ng TEQ/dscm or control of temperature of flue gas at the inlet 
to the control device to 400 [deg]F), we propose a numerical beyond-
the-floor standard for those boilers, as discussed below in the 
text.
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated use of activated carbon injection systems or carbon 
beds as beyond-the-floor control for further reduction of dioxin/furan 
emissions. Activated carbon has been demonstrated for controlling 
dioxin/furans in various combustion applications.
    a. Beyond-the-Floor Considerations for Boilers Equipped with Dry 
Control Systems. For liquid fuel-fired boilers using dry air pollution 
control equipment, we evaluated a beyond-the-floor level of 0.40 ng 
TEQ/dscm based on activated carbon injection or control of flue gas 
temperature not to exceed 400 [deg]F at the inlet to the particulate 
matter control device. The national incremental annualized compliance 
cost for sources to meet this beyond-the-floor level rather than comply 
with the floor controls would be approximately $80,000 and would 
provide an incremental reduction in dioxin/furan emissions beyond the 
MACT floor

[[Page 21285]]

controls of 0.06 grams TEQ per year for a cost-effectiveness of $1.3 
million per additional gram of dioxin/furan removed. We evaluated the 
nonair quality health and environmental impacts and energy effects of 
this beyond-the-floor standard and estimate that the amount of 
hazardous waste generated would increase by 100 tons per year, an 
additional 25 trillion Btu per year of natural gas would be consumed, 
and electricity consumption would increase by 0.50 million kW-hours per 
year.
    We judge that the cost to achieve this beyond-the-floor level is 
warranted given our special concern about dioxin/furan. Dioxin/furan 
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 our dioxin/furan for priority MACT control 
in CAA section 112(c)(6). See S. Rep. No. 128, 101st Cong. 1st Sess. at 
154-155. In addition, we note that the beyond-the-floor emission level 
of 0.40 ng TEQ/dscm is consistent with historically controlled levels 
under MACT for hazardous waste incinerators and cement kilns, and 
Portland cement plants. See Sec. Sec.  63.1203(a)(1), 63.1204(a)(1), 
and 63.1343(d)(3). Also, EPA has determined previously in the 1999 
Hazardous Waste Combustor MACT final rule that dioxin/furan in the 
range of 0.40 ng TEQ/dscm or less are necessary for the MACT standards 
to be considered generally protective of human health under RCRA (using 
the 1985 cancer slope factor), thereby eliminating the need for 
separate RCRA standards under the authority of RCRA section 3005(c)(3) 
and 40 CFR 270.10(k). Finally, we note that this decision is not 
inconsistent with EPA's decision not to promulgate beyond-the-floor 
standards for dioxin/furan for hazardous waste burning lightweight 
aggregate kilns, cement kilns, and incinerators at cost-effectiveness 
values in the range of $530,000 to $827,000 per additional gram of 
dioxin/furan TEQ removed. See 64 FR at 52892, 52876, and 52961. In 
those cases, EPA determined that controlling dioxin/furan emissions 
from a level of 0.40 ng TEQ/dscm to a beyond-the-floor level of 0.20 ng 
TEQ/dscm was not warranted because dioxin/furan levels below 0.40 ng 
TEQ/dscm are generally considered to be below the level of health risk 
concern.
    For these reasons, we believe that proposing a beyond-the-floor 
standard of 0.40 ng TEQ/dscm is warranted notwithstanding the nonair 
quality health and environmental impacts and energy effects identified 
above and costs of approximately $1.3 million per additional gram of 
dioxin/furan TEQ removed. We specifically request comment on our 
decision to propose this beyond-the-floor standard.
    b. Beyond-the-Floor Considerations for Boilers Equipped with Wet or 
No Control Systems. For liquid fuel-fired boilers equipped with wet or 
no air pollution control systems, we evaluated a beyond-the-floor level 
of 0.20 ng TEQ/dscm based on activated carbon. The national incremental 
annualized compliance cost for these sources to meet this beyond-the-
floor level rather than comply with the floor controls would be 
approximately $550,000 and would provide an incremental reduction in 
dioxin/furan emissions beyond the MACT floor controls of 0.12 grams TEQ 
per year. We evaluated the nonair quality health and environmental 
impacts and energy effects of this beyond-the-floor standard and 
estimate that the amount of hazardous waste generated would increase by 
100 tons per year, an additional 25 trillion Btu per year of natural 
gas would be consumed, an additional 4 million gallons per year of 
water would be used, and electricity consumption would increase by 0.50 
million kW-hours per year. We are not proposing a beyond-the-floor 
standard of 0.20 ng TEQ/dscm for liquid boilers that use a wet or no 
air pollution control system because it would not be cost-effective at 
$4.6 million per gram of TEQ removed.
    We are also considering an alternative beyond-the-floor standard 
for existing liquid fuel boilers with wet or no particulate matter 
control devices of 0.40 ng TEQ/dscm. Although all but one source for 
which we have data are currently achieving this emission level, boilers 
for which we do not have dioxin/furan emissions data may have emissions 
higher than 0.40 ng TEQ/dscm. In addition, dioxin/furan emissions from 
a given boiler may vary over time. Other factors that may contribute 
substantially to dioxin/furan formation, such as the level and type of 
soot on boiler tubes, or feeding metals that catalyze dioxin/furan 
formation reactions, differ across boilers and may change over time at 
a given boiler. Thus, dioxin/furan levels for these sources may be 
higher than 0.40 ng TEQ/dscm. For example, we recently obtained dioxin/
furan emissions data for a liquid fuel-fired boiler equipped with a wet 
emission control system documenting emissions of 1.4 ng TEQ/dscm.\147\ 
To control dioxin/furan emissions to a beyond-the-floor standard of 
0.40 ng TEQ/dscm, you would use activated carbon. We specifically 
request comment on this beyond-the-floor option, including how we 
should estimate compliance costs and emissions reductions.
---------------------------------------------------------------------------

    \147\ These data were recently obtained and are not in the MACT 
data base. See ``Region 4 Boiler Dioxin Data,'' Excel spreadsheet, 
March 10, 2004.
---------------------------------------------------------------------------

3. What Is the Rationale for the MACT Floor for New Sources?
    The calculated floor level for new liquid fuel boilers equipped 
with dry air pollution control systems is 0.015 ng TEQ/dscm, which we 
identified using the Emissions Approach. If dioxin/furan emissions 
could be controlled predominantly by controlling the gas temperature at 
the inlet to the dry particulate matter control device, this would be 
the emission level that the single best performing source could be 
expected to achieve in 99 out of 100 future tests when operating under 
conditions identical to the compliance test conditions during which the 
emissions data were obtained. This emission level may not be replicable 
by this source and duplicable by other (new) sources, however, because 
factors other than flue gas temperature control at the control device 
may affect dioxin/furan emissions. See discussion of this issue in the 
context of the floor level for existing sources. Therefore, we propose 
to establish the floor level as 0.015 ng TEQ/dscm or control of flue 
gas temperature not to exceed 400 [deg]F at the inlet to the 
particulate matter control device.
    As previously discussed, we believe that it would be inappropriate 
to establish a numerical dioxin/furan emission floor level for liquid 
boilers with wet or with no air pollution control systems. Therefore, 
we propose floor control for these units as good combustion practices 
provided by complying with the proposed destruction and removal 
efficiency and carbon monoxide/hydrocarbon standards.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated use of activated carbon as beyond-the-floor control 
for further reduction of dioxin/furan emissions. Activated carbon has 
been demonstrated for controlling dioxin/furan in various combustion 
applications.
    a. Beyond-the-Floor Considerations for Boilers Equipped with Dry 
Control Systems. For liquid fuel-fired boilers using dry air pollution 
control equipment, we evaluated a beyond-the-floor level of 0.01 ng 
TEQ/dscm using activated carbon injection. The national incremental 
annualized compliance cost

[[Page 21286]]

for a source with an average gas flowrate to meet this beyond-the-floor 
level rather than comply with the floor controls would be approximately 
$0.15 million and would provide an incremental reduction in dioxin/
furan emissions beyond the MACT floor controls of 0.005 grams TEQ per 
year. We evaluated the nonair quality health and environmental impacts 
and energy effects of this beyond-the-floor standard and estimate that, 
for a new liquid fuel-fired boiler with average gas flowrate, the 
amount of hazardous waste generated would increase by 120 tons per year 
and electricity consumption would increase by 0.1 million kW-hours per 
year. After considering these impacts and costs of approximately $32 
million per additional gram of dioxin/furan removed, we are not 
proposing a beyond-the-floor standard of 0.01 ng TEQ/dscm for liquid 
fuel-fired boilers using dry air pollution control systems.
    We are also considering an alternative beyond-the-floor standard of 
0.40 ng TEQ/dscm for new liquid fuel boilers equipped with a dry 
particulate matter control device. A new source that achieves the floor 
level by controlling the gas temperature at the inlet to the dry 
particulate matter control device to 400 [deg]F may have dioxin/furan 
emissions at levels far exceeding 0.40 ng TEQ/dscm. See discussion 
above regarding factors other than gas temperature at the control 
device that can affect dioxin/furan emissions from liquid fuel-fired 
boilers (and discussion of emissions of 2.4 ng TEQ/dscm for a boiler 
operating a fabric filter at 410 [deg]F). Therefore, it may be 
appropriate to establish a beyond-the-floor standard to limit emissions 
to 0.40 ng TEQ/dscm based on use of activated carbon injection. We also 
note that this beyond-the-floor standard may be appropriate to ensure 
that emission levels from new sources do not exceed the proposed 0.40 
ng TEQ/dscm beyond-the-floor standard for existing sources. Because 
standards for new sources are based on the single best performing 
source while standards for existing sources are based on the average of 
the best 12% (or best 5) performing sources, standards for new sources 
should not be less stringent than standards for existing sources. We 
specifically request comment on this beyond-the-floor option, including 
how we should estimate compliance costs and emissions reductions.
    b. Beyond-the-Floor Considerations for Boilers Equipped with Wet or 
No Control Systems. We evaluated a beyond-the-floor level of 0.20 ng 
TEQ/dscm for liquid fuel-fired boilers equipped with wet or with no air 
pollution control systems based on use of activated carbon. The 
national incremental annualized compliance cost for a source with 
average gas flowrate to meet this beyond-the-floor level rather than 
comply with the floor controls would be approximately $0.15 million and 
would provide an incremental reduction in dioxin/furan emissions beyond 
the MACT floor controls of 0.06 grams TEQ per year. We evaluated the 
nonair quality health and environmental impacts and energy effects of 
this beyond-the-floor standard and estimate that, for a source with 
average gas flowrate, the amount of hazardous waste generated would 
increase by 120 tons per year and electricity consumption would 
increase by 0.1 million kW-hours per year. After considering these 
impacts and costs of approximately $2.4 million per additional gram of 
dioxin/furan removed, we are not proposing a beyond-the-floor standard 
for liquid fuel-fired boilers using a wet or no air pollution control 
system.
    We are also considering an alternative beyond-the-floor standard of 
0.40 ng TEQ/dscm for new liquid fuel boilers equipped with wet or with 
no air pollution control systems. A new source that achieves the floor 
level--compliance with the standards for carbon monoxide/hydrocarbon 
and destruction and removal efficiency--may have high dioxin/furan 
emissions at levels far exceeding 0.40 ng TEQ/dscm. See discussion 
above regarding factors other than gas temperature at the control 
device that can affect dioxin/furan emissions from liquid fuel-fired 
boilers. Therefore, it may be appropriate to establish a beyond-the-
floor standard to limit emissions to 0.40 ng TEQ/dscm based on use of 
activated carbon. We specifically request comment on this beyond-the-
floor option, including how we should estimate compliance costs and 
emissions reductions.

B. What Is the Rationale for the Proposed Standards for Mercury?

    We propose to establish standards for existing liquid fuel-fired 
boilers that limit emissions of mercury to 3.7E-6 lbs mercury emissions 
attributable to the hazardous waste per million Btu heat input from the 
hazardous waste. The proposed standards for new sources would be 3.8E-7 
lbs mercury emissions attributable to the hazardous waste per million 
Btu heat input from the hazardous waste.\148\ These standards are 
expressed as hazardous waste thermal emission concentrations because 
liquid fuel-fired boilers burn hazardous waste for energy recovery. See 
discussion in Part Two, Section IV.B of the preamble.
---------------------------------------------------------------------------

    \148\ As information, EPA did not propose MACT emission 
standards for mercury for liquid fuel-fired boilers that do not burn 
hazardous waste. See 68 FR 1660 (Jan. 13, 2003). Note that, in 
today's rule, we propose to control mercury only in hazardous waste 
fuels, an option obviously not available to boilers that do not burn 
hazardous waste.
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
    MACT floor for existing sources is 3.7E-6 lbs mercury emissions 
attributable to the hazardous waste per million Btu heat input from the 
hazardous waste, which is based primarily by controlling the feed 
concentration of mercury in the hazardous waste. Approximately 11% of 
liquid boilers also use wet scrubbers that can control emissions of 
mercury.
    We have normal emissions data within the range of normal emissions 
for 32% of the sources.\149\ The normal mercury stack emissions in our 
data base are all less than 7 [mu]g/dscm. These emissions are expressed 
as mass of mercury (from all feedstocks) per unit of stack gas. 
Hazardous waste thermal emissions, available for 12% of sources, range 
from 1.0E-7 to 1.0E-5 lbs mercury emissions attributable to the 
hazardous waste per million Btu heat input from the hazardous waste. 
Hazardous waste thermal emissions represent the mass of mercury 
contributed by the hazardous waste per million Btu contributed by the 
hazardous waste.
---------------------------------------------------------------------------

    \149\ Several owners and operators have used the emissions data 
as ``data in lieu of testing'' emissions from other, identical 
boilers at the same facility. For purposes of identifying the number 
of boilers represented in this paragraph, the percentage includes 
the data-in-lieu sources.
---------------------------------------------------------------------------

    To identify the MACT floor, we evaluated all normal emissions data 
using the Emissions Approach. The calculated floor is 3.7E-6 lbs 
mercury emissions attributable to the hazardous waste per million Btu 
heat input from the hazardous waste. This is an emission level that the 
average of the best performing sources could be expected to achieve in 
99 of 100 future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. We estimate that this floor level is being achieved by 40% of 
sources and would reduce mercury emissions by 0.68 tons per year.
    Because the floor level is based on normal emissions data, 
compliance would be documented by complying with a hazardous waste 
mercury thermal feed concentration on an annual rolling average. See 
discussion in Part Two, Section XIV.F below.
    We did not use the SRE/Feed Approach to identify the floor level 
because the vast majority of mercury feed levels in the hazardous waste 
and

[[Page 21287]]

the emissions measurements did not have detectable concentrations of 
mercury. Given that a system removal efficiency, or SRE, is the 
percentage of mercury emitted compared to the amount fed, we concluded 
that it would be inappropriate to base this analysis on SREs that were 
derived from measurements below detectable levels.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified two potential beyond-the-floor techniques for control 
of mercury: (1) Activated carbon injection; and (2) control of mercury 
in the hazardous waste feed. For reasons discussed below, we are not 
proposing a beyond-the-floor standard for mercury.
    a. Use of Activated Carbon Injection. We evaluated activated carbon 
injection as beyond-the-floor control for further reduction of mercury 
emissions. Activated carbon has been demonstrated for controlling 
mercury in several combustion applications; however, currently no 
liquid fuel boilers burning hazardous waste uses activated carbon 
injection. We evaluated a beyond-the-floor level of 1.1E-6 lbs mercury 
emissions attributable to the hazardous waste per million Btu heat 
input from the hazardous waste. The national incremental annualized 
compliance cost for liquid fuel-fired boilers to meet this beyond-the-
floor level rather than comply with the floor controls would be 
approximately $12 million and would provide an incremental reduction in 
mercury emissions beyond the MACT floor controls of 0.097 tons per 
year. We evaluated nonair quality health and environmental impacts and 
energy effects of using activated carbon injection to meet this beyond-
the-floor emission level and estimate that the amount of hazardous 
waste generated would increase by 4,800 tons per year and that sources 
would consume an additional 44 trillion Btu per year of natural gas and 
use an additional 9.6 million kW-hours per year beyond the requirements 
to achieve the floor level. Therefore, based on these factors and costs 
of approximately $124 million per additional ton of mercury removed, we 
are not proposing a beyond-the-floor standard based on activated carbon 
injection.\150\
---------------------------------------------------------------------------

    \150\ We note that the beyond-the-floor dioxin/furan standard we 
propose for liquid fuel-fired boilers equipped with dry particulate 
matter control devices would also provide no-cost beyond-the-floor 
mercury control for sources that use activated carbon injection to 
control dioxin/furan. If such sources achieve the beyond-the-floor 
dioxin/furan standard by other means (control of temperature at the 
inlet to the control device; control of feedrate of metals that may 
catalyze formation of dioxin/furan), however, collateral reductions 
in mercury emissions would not be realized.
---------------------------------------------------------------------------

    b. Feed Control of Mercury in the Hazardous Waste. We also 
evaluated a beyond-the-floor level of 3.0E-6 lbs mercury emissions 
attributable to the hazardous waste per million Btu heat input from the 
hazardous waste, which represents a 20% reduction from the floor level. 
The national incremental annualized compliance cost for liquid fuel-
fired boilers to meet this beyond-the-floor level rather than comply 
with the floor controls would be approximately $4.2 million and would 
provide an incremental reduction in mercury emissions beyond the MACT 
floor controls of 0.036 tons per year. Nonair quality health and 
environmental impacts and energy effects are not significant factors 
for feedrate control. Therefore, based on these factors and costs of 
approximately $115 million per additional ton of mercury removed, we 
are not proposing a beyond-the-floor standard based on feed control of 
mercury in the hazardous waste.
    For the reasons discussed above, we do not propose a beyond-the-
floor standard for mercury for existing sources. We propose a standard 
based on the floor level: 3.7E-6 lbs mercury emissions attributable to 
the hazardous waste per million Btu heat input from the hazardous 
waste.
3. What Is the Rationale for the MACT Floor for New Sources?
    The MACT floor for new sources for mercury would be 3.8E-7 lbs 
mercury emissions attributable to the hazardous waste per million Btu 
heat input from the hazardous waste and would be implemented as an 
annual average because it is based on normal emissions data. This is an 
emission level that the single best performing source identified with 
the Emissions Approach could be expected to achieve in 99 of 100 future 
tests when operating under operating conditions identical to the 
compliance test conditions during which the emissions data were 
obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated activated carbon injection as beyond-the-floor control 
to achieve an emission level of 2.0E-7 lbs mercury emissions 
attributable to the hazardous waste per million Btu heat input from the 
hazardous waste. The incremental annualized compliance cost for a new 
liquid fuel-fired boiler with average gas flowrate to meet this beyond-
the-floor level, rather than comply with the floor level, would be 
approximately $0.15 million and would provide an incremental reduction 
in mercury emissions of less than 0.0002 tons per year, for a cost-
effectiveness of $1 billion per ton of mercury removed. We evaluated 
the nonair quality health and environmental impacts and energy effects 
of this beyond-the-floor standard and estimate that, for a new liquid 
fuel-fired boiler with average gas flowrate, the amount of hazardous 
waste generated would increase by 120 tons per year and electricity 
consumption would increase by 0.1 million kW-hours per year. Although 
nonair quality health and environmental impacts and energy effects are 
not significant factors, we are not proposing a beyond-the-floor 
standard based on activated carbon injection for new sources because it 
would not be cost-effective. Therefore, we propose a mercury standard 
based on the floor level: 3.8E-7 lbs mercury emissions attributable to 
the hazardous waste per million Btu heat input from the hazardous 
waste.

C. What Is the Rationale for the Proposed Standards for Particulate 
Matter?

    The proposed standards for particulate matter for liquid fuel-fired 
boilers are 59 mg/dscm (0.026 gr/dscf) for existing sources and 17 mg/
dscm (0.0076 gr/dscf) for new sources.\151\ The particulate matter 
standard serves as a surrogate for nonenumerated HAP metal emissions 
attributable to the hazardous waste fuel burned in the boiler. Although 
the particulate matter standard would also control nonmercury HAP metal 
from nonhazardous waste fuels, the natural gas or fuel oil these 
boilers burn as primary or auxiliary fuel do not contain significant 
levels of metal HAP.
---------------------------------------------------------------------------

    \151\ As information, EPA proposed MACT standards for 
particulate matter for solid fuel-fired industrial, commercial, and 
institutional boilers that do not burn hazardous waste of 0.035 gr/
dscf for existing sources and 0.013 gr/dscf for new sources.
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
    Few liquid fuel-fired boilers are equipped particulate matter 
control equipment such as electrostatic precipitators and baghouses, 
and, therefore, many sources control particulate matter emissions by 
limiting the ash content of the hazardous waste. We have compliance 
test emissions data from nearly all liquid boilers representing maximum 
allowable emissions. Particulate emissions range from 0.0008 to 0.078 
gr/dscf.
    To identify the floor level, we evaluated the compliance test 
emissions

[[Page 21288]]

data associated with the most recent test campaign using the APCD 
Approach. The calculated floor is 72 mg/dscm (0.032 gr/dscf), which 
considers emissions variability. This is an emission level that the 
average of the performing sources could be expected to achieve in 99 of 
100 future tests when operating under operating conditions identical to 
the compliance test conditions during which the emissions data were 
obtained. We estimate that this floor level is being achieved by 44% of 
sources and would reduce particulate matter emissions by 1,200 tons per 
year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated use of fabric filters to improve particulate matter 
control to achieve a beyond-the-floor standard of 36 mg/dscm (0.016 gr/
dscf). The national incremental annualized compliance cost for liquid 
fuel-fired boilers to meet this beyond-the-floor level rather than 
comply with the floor controls would be approximately $16 million and 
would provide an incremental reduction in particulate matter emissions 
beyond the MACT floor controls of 520 tons per year. We evaluated the 
nonair quality health and environmental impacts and energy effects of 
this beyond-the-floor standard and estimate that the amount of 
hazardous waste generated would increase by 520 tons per year and 
electricity consumption would increase by 13 million kW-hours per year. 
After considering these factors and costs of approximately $30,000 per 
additional ton of particulate matter removed, we are not proposing a 
beyond-the-floor standard.
    For the reasons discussed above, we propose a standard for 
particulate matter for existing liquid fuel-fired boilers based on the 
floor level: 72 mg/dscm (0.032 gr/dscf).
3. What Is the Rational for the MACT Floor for New Sources?
    MACT floor for new sources would be 17 mg/dscm (0.0076 gr/dscf), 
considering emissions variability. This is an emission level that the 
single best performing source identified by the APCD Approach (i.e., 
the source using a fabric filter \152\ with the lowest emissions) could 
be expected to achieve in 99 of 100 future tests when operating under 
operating conditions identical to the compliance test conditions during 
which the emissions data were obtained.
---------------------------------------------------------------------------

    \152\ The source also is equipped with a high efficiency 
particulate air (HEPA) filter.
---------------------------------------------------------------------------

4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated use of an advanced fabric filter using high efficiency 
membrane bag material and a low air to cloth ratio to achieve a beyond-
the-floor emission level of 9 mg/dscm (0.0040 gr/dscf). The incremental 
annualized cost for a new liquid fuel-fired boiler with average gas 
flowrate to meet this beyond-the-floor level, rather than comply with 
the floor level, would be approximately $0.15 million and would provide 
an incremental reduction in particulate emissions of approximately 2.9 
tons per year, for a cost-effectiveness of $53,000 per ton of 
particulate matter removed. We evaluated the nonair quality health and 
environmental impacts and energy effects of this beyond-the-floor 
standard and estimate that, for a new liquid fuel-fired boiler with 
average gas flowrate, the amount of hazardous waste generated would 
increase by 3 tons per year and electricity consumption would increase 
by 0.54 million kW-hours per year. Considering these factors and cost-
effectiveness, we conclude that a beyond-the-floor standard of 9 mg/
dscm is not warranted.
    For the reasons discussed above, we propose a floor-based standard 
for particulate matter for new liquid fuel-fired boilers: 9.8 mg/dscm 
(0.0043 gr/dscf)

D. What Is the Rationale for the Proposed Standards for Semivolatile 
Metals?

    We propose a standard for existing liquid fuel-fired boilers that 
limits emissions of semivolatile metals (cadmium and lead, combined) to 
1.1E-5 lbs semivolatile metals emissions attributable to the hazardous 
waste per million Btu heat input from the hazardous waste. The proposed 
standard for new sources is 4.3E-6 lbs semivolatile metals emissions 
attributable to the hazardous waste per million Btu heat input from the 
hazardous waste.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    MACT floor for existing sources is 1.1E-5 lbs semivolatile metals 
emissions attributable to the hazardous waste per million Btu heat 
input of the hazardous waste, which is based on particulate matter 
control (for those few sources using a control device) and controlling 
the feedrate of semivolatile metals in the hazardous waste.
    We have emissions data within the range of normal emissions for 
nearly 40% of the sources.\153\ The normal semivolatile stack emissions 
in our database range from less than 1 to 46 ug/dscm. These emissions 
are expressed conventionally as mass of semivolatile metals (from all 
feedstocks) per unit of stack gas. Hazardous waste thermal emissions, 
available for 25% of sources, range from 1.2E-6 to 4.8E-5 lbs 
semivolatile metals emissions attributable to the hazardous waste per 
million Btu heat input of the hazardous waste.
---------------------------------------------------------------------------

    \153\ Several owners and operators have used the emissions data 
as ``data in lieu of testing'' emissions from other, identical 
boilers at the same facility. For purposes of identifying the number 
of boilers represented in this paragraph, the percentages include 
the data-in-lieu sources.
---------------------------------------------------------------------------

    We identified a MACT floor of 1.1E-5 expressed as a hazardous waste 
thermal emission by applying the Emissions Approach to the normal 
hazardous waste thermal emissions data.\154\ This is an emission level 
that the average of the best performing sources could be expected to 
achieve in 99 of 100 future tests when operating under conditions 
identical to the compliance test conditions during which the emissions 
data were obtained. We estimate that this floor level is being achieved 
by 33% of sources and would reduce semivolatile metals emissions by 1.7 
tons per year.
---------------------------------------------------------------------------

    \154\ We propose to use the Emissions Approach rather than the 
SRE/Feed approach because our data base is comprised of emissions 
obtained during normal rather than compliance test operations. 
Because of the relatively low semivolatile metal feedrates during 
normal operations, we are concerned that the system removal 
efficiencies that we would calculate may be inaccurate (e.g., 
sampling and analysis imprecision at low feed rates can have a 
substantial impact on calculated system removal efficiencies).
---------------------------------------------------------------------------

    Because the floor level is based on normal emissions data, 
compliance would be documented by complying with a hazardous waste 
mercury thermal feed concentration on an annual rolling average. See 
discussion in Part Two, Section XIV.F below.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified two potential beyond-the-floor techniques for control 
of semivolatile metals: (1) Improved particulate matter control; and 
(2) control of mercury in the hazardous waste feed. For reasons 
discussed below, we are not proposing a beyond-the-floor standard for 
semivolatile metals.
    a. Improved Particulate Matter Control. We evaluated installation 
of a new fabric filter or improved design, operation, and maintenance 
of the existing electrostatic precipitator and fabric filter as beyond-
the-floor control

[[Page 21289]]

for further reduction of semivolatile metals emissions. We evaluated a 
beyond-the-floor level of 5.5E-6 lbs semivolatile metals emissions 
attributable to the hazardous waste per million Btu heat input from the 
hazardous waste. The national incremental annualized compliance cost 
for liquid fuel-fired boilers to meet this beyond-the-floor level 
rather than comply with the floor controls would be approximately $6.5 
million and would provide an incremental reduction in semivolatile 
metals emissions beyond the MACT floor controls of 0.06 tons per year. 
We evaluated nonair quality health and environmental impacts and energy 
effects and determined that this beyond-the-floor option would increase 
the amount of hazardous waste generated by approximately 45 tons per 
year and would increase electricity usage by 0.8 million kW-hours per 
year. After considering these factors and costs of approximately $100 
million per additional ton of semivolatile metals removed, we are not 
proposing a beyond-the-floor standard based on improved particulate 
matter control.
    b. Feed Control of Semivolatile Metals in the Hazardous Waste. We 
also evaluated a beyond-the-floor level of 8.8E-6 lbs semivolatile 
metals emissions attributable to the hazardous waste per million Btu 
heat input from the hazardous waste, which represents a 20% reduction 
from the floor level. The national incremental annualized compliance 
cost for liquid fuel-fired boilers to meet this beyond-the-floor level 
rather than comply with the floor controls would be approximately $4.8 
million and would provide an incremental reduction in semivolatile 
metals emissions beyond the MACT floor controls of 0.06 tons per year. 
Nonair quality health and environmental impacts and energy effects are 
not significant factors for feedrate control. Therefore, considering 
these factors and costs of approximately $81 million per additional ton 
of semivolatile metals removed, we are not proposing a beyond-the-floor 
standard based on feed control of semivolatile metals in the hazardous 
waste.
    For the reasons discussed above, we propose a floor standard for 
semivolatile metals for existing liquid fuel-fired boilers of 1.1E-5 
lbs semivolatile metals emissions attributable to the hazardous waste 
per million Btu heat input from the hazardous waste.
3. What Is the Rationale for the MACT Floor for New Sources?
    The MACT floor for new sources for semivolatile metals would be 
4.3E-6 lbs semivolatile metals emissions attributable to the hazardous 
waste per million Btu heat input from the hazardous waste. This is an 
emission level that the single best performing source identified with 
the Emissions Approach \155\ could be expected to achieve in 99 of 100 
future tests when operating under operating conditions identical to the 
compliance test conditions during which the emissions data were 
obtained.
---------------------------------------------------------------------------

    \155\ We use the Emissions Approach rather than the SRE/Feed 
Approach when we use normal rather than compliance test data to 
establish the standard, as discussed previously.
---------------------------------------------------------------------------

    Because the floor level is based on normal emissions data, 
compliance would be documented by complying with a hazardous waste 
mercury thermal feed concentration on an annual rolling average. See 
discussion in Part Two, Section XIV.F below.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated a beyond-the-floor level of 2.1E-6 lbs semivolatile 
metals emissions attributable to the hazardous waste per million Btu 
heat input from the hazardous waste based on an advanced fabric filter 
using high efficiency membrane bag material and a low air to cloth 
ratio. The incremental annualized compliance cost for a new liquid 
fuel-fired boiler with average gas flowrate to meet this beyond-the-
floor level, rather than comply with the floor level, would be 
approximately $0.15 million and would provide an incremental reduction 
in semivolatile metals emissions of less than 0.002 tons per year, for 
a cost-effectiveness of $87 million per ton of semivolatile metals 
removed. We evaluated the nonair quality health and environmental 
impacts and energy effects of this beyond-the-floor standard and 
estimate that, for a new liquid fuel-fired boiler with average gas 
flowrate, the amount of hazardous waste generated would increase by 2 
tons per year and electricity consumption would increase by 0.54 
million kW-hours per year. Considering these factors and cost-
effectiveness, we conclude that a beyond-the-floor standard is not 
warranted. Therefore, we propose a semivolatile metals standard based 
on the floor level: 4.3E-6 lbs semivolatile metals emissions 
attributable to the hazardous waste per million Btu heat input from the 
hazardous waste for new sources.

E. What Is the Rationale for the Proposed Standards for Chromium?

    We propose to establish standards for existing and new liquid fuel-
fired boilers that limit emissions of chromium to 1.1E-4 lbs and 3.6E-5 
lbs chromium emissions attributable to the hazardous waste per million 
Btu heat input from the hazardous waste, respectively.
    We propose to establish emission standards on chromium-only because 
our data base has very limited compliance test data on emissions of 
total low volatile metals: arsenic, beryllium, and chromium. We have 
compliance test data on only two sources for total low volatile metals 
emissions while we have compliance test data for 12 sources for 
chromium-only. Although we have total low volatile metals emissions for 
12 sources when operating under normal operations, we prefer to use 
compliance test data to establish the floor because they better address 
emissions variability.
    By establishing a low volatile metal floor based on chromium 
emissions only we are relying on the particulate matter standard to 
control the other enumerated low volatile metals--arsenic and 
beryllium--as well as nonenumerated metal HAP. We request comment on 
this approach and note that, as discussed below, an alternative 
approach would be to establish a MACT floor based on normal emissions 
data for all three enumerated low volatile metals.
    We request comment on whether the compliance test data for 
chromium-only are appropriate for establishing a MACT floor for 
chromium. We are concerned that some sources in our data base may have 
used chromium as a surrogate for arsenic and beryllium during RCRA 
compliance testing such that their chromium emissions may be more 
representative of their total low volatile metals emissions than only 
chromium. If we determine this to be the case, we could apply the floor 
we calculate using chromium emissions to total low volatile metal 
emissions. Alternatively, we could use the normal emissions data we 
have on 12 sources and our MACT methodology to establish a total low 
volatile metals floor.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    MACT floor for existing sources is 1.1E-4 lbs chromium emissions 
attributable to the hazardous waste per million Btu heat input from the 
hazardous waste, which is based on particulate matter control (for 
those few sources using a control device) and controlling the feed 
concentration of chromium in the hazardous waste.
    We have compliance test emissions data for approximately 17% of the

[[Page 21290]]

sources.\156\ The compliance test chromium stack emissions in our 
database range from 2 to 900 ug/dscm. These emissions are expressed as 
mass of chromium (from all feedstocks) per unit of stack gas. Hazardous 
waste thermal emissions, available for 13% of sources, range from 3.2E-
6 to 8.8E-4 lbs chromium emissions attributable to the hazardous waste 
per million Btu heat input from the hazardous waste.
---------------------------------------------------------------------------

    \156\ Several owners and operators have used the emissions data 
as ``data in lieu of testing'' emissions from other, identical 
boilers at the same facility. For purposes of identifying the number 
of boilers represented in this paragraph, the percentages include 
the data-in-lieu sources.
---------------------------------------------------------------------------

    To identify the floor level, we evaluated all compliance test 
thermal emissions data using the SRE/Feed Approach (see discussion in 
Section VI.C above). The calculated floor is 1.1E-4 lbs chromium 
emissions attributable to the hazardous waste per million Btu heat 
input from the hazardous waste feed, which considers emissions 
variability. This is an emission level that the average of the best 
performing sources could be expected to achieve in 99 of 100 future 
tests when operating under conditions identical to the compliance test 
conditions during which the emissions data were obtained. We estimate 
that this floor level is being achieved by 36% of sources and would 
reduce chromium emissions by 9.4 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified two potential beyond-the-floor techniques for control 
of chromium emissions: (1) Use of a fabric filter to improve 
particulate matter control; and (2) control of chromium in the 
hazardous waste feed. For reasons discussed below, we are not proposing 
a beyond-the-floor standard for chromium.
    a. Use of a Fabric Filter to Improve Particulate Matter Control. We 
evaluated use of a fabric filter as beyond-the-floor control for 
further reduction of chromium emissions. We evaluated a beyond-the-
floor level of 5.5E-5 lbs chromium emissions attributable to the 
hazardous waste per million Btu heat input from the hazardous waste. 
The national incremental annualized compliance cost for liquid fuel-
fired boilers to meet this beyond-the-floor level rather than comply 
with the floor controls would be approximately $5.9 million and would 
provide an incremental reduction in chromium emissions beyond the MACT 
floor controls of 0.50 tons per year. We evaluated nonair quality 
health and environmental impacts and energy effects and determined that 
this beyond-the-floor option would increase the amount of hazardous 
waste generated by approximately 160 tons per year and would increase 
electricity usage by 3.0 million kW-hours per year. Based on these 
impacts and a cost of approximately $12 million per additional ton of 
chromium removed, we are not proposing a beyond-the-floor standard 
based on improved particulate matter control.
    b. Feed Control of Chromium in the Hazardous Waste. We evaluated 
additional feed control of chromium in the hazardous waste as a beyond-
the-floor control technique to reduce floor emission levels by 25% to 
achieve a standard of 8.8E-5 lbs chromium emissions attributable to the 
hazardous waste per million Btu heat input from the hazardous waste. 
This beyond-the-floor level of control would reduce chromium by an 
additional 0.20 tons per year at a cost-effectiveness of $22 million 
per ton of chromium removed. Nonair quality health and environmental 
impacts and energy effects are not significant factors for feedrate 
control. We conclude that use of additional hazardous waste chromium 
feedrate control would not be cost-effective and are not proposing a 
beyond-the-floor standard based on this control technique.
    For the reasons discussed above, we do not propose a beyond-the-
floor standard for chromium. Consequently, we propose to establish the 
emission standard for existing liquid fuel-fired boilers at the floor 
level: a hazardous waste thermal emission standard of 1.1E-4 lbs 
chromium emissions attributable to hazardous waste per million Btu of 
hazardous waste feed.
3. What Is the Rationale for the MACT Floor for New Sources?
    The MACT floor for new sources for chromium would be 3.6E-5 lbs 
chromium emissions attributable to the hazardous waste per million Btu 
heat input from the hazardous waste feed. This is an emission level 
that the single best performing source identified with the SRE/Feed 
Approach could be expected to achieve in 99 of 100 future tests when 
operating under operating conditions identical to the compliance test 
conditions during which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated use of an advanced fabric filter using high efficiency 
membrane bag material and a low air to cloth ratio as beyond-the-floor 
control to reduce chromium emissions to a beyond-the-floor level of 
1.8E-5 lbs chromium emissions attributable to the hazardous waste per 
million Btu heat input from the hazardous waste. The incremental 
annualized compliance cost for a new liquid fuel-fired boiler with 
average gas flowrate to meet this beyond-the-floor level, rather than 
comply with the floor level, would be approximately $0.15 million and 
would provide an incremental reduction in chromium emissions of 0.014 
tons per year, for a cost-effectiveness of $11 million per ton of 
chromium removed. We evaluated the nonair quality health and 
environmental impacts and energy effects of this beyond-the-floor 
standard and estimate that, for a new liquid fuel-fired boiler with 
average gas flowrate, the amount of hazardous waste generated would 
increase by 2 tons per year and electricity consumption would increase 
by 0.54 million kW-hours per year. Considering these factors and cost-
effectiveness, we conclude that a beyond-the-floor standard is not 
warranted. Therefore, we propose a chromium emission standard for new 
sources based on the floor level: 3.6E-5 lbs chromium emissions 
attributable to the hazardous waste per million Btu heat input from the 
hazardous waste feed.

F. What Is the Rationale for the Proposed Standards for Total Chlorine?

    We are proposing to establish a standard for existing liquid fuel-
fired boilers that limit emissions of hydrogen chloride and chlorine 
gas (i.e., total chlorine) to 2.5E-2 lbs total chlorine emissions 
attributable to the hazardous waste per million Btu heat input from the 
hazardous waste. The proposed standard for new sources would be 7.2E-4 
lbs total chlorine emissions attributable to the hazardous waste per 
million Btu heat input from the hazardous waste.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Most liquid fuel-fired boilers that burn hazardous waste do not 
have back-end controls such as wet scrubbers for total chlorine 
control. For these sources, total chlorine emissions are controlled by 
most sources by controlling the feedrate of chlorine in the hazardous 
waste feed. Approximately 15% of sources use wet scrubbing systems to 
control total chlorine emissions.
    We have compliance test data representing maximum emissions for 40% 
of the boilers. Total chlorine emissions range from less than 1 to 900 
ppmv. Hazardous waste thermal emissions, available for 27% of boilers, 
range from 1.00E-4 to 1.4 lbs total

[[Page 21291]]

chlorine emissions attributable to the hazardous waste per million Btu 
heat input from the hazardous waste.
    The calculated floor is 2.5E-2 lbs total chlorine emissions 
attributable to the hazardous waste per million Btu heat input from the 
hazardous waste using the SRE/Feed Approach to identify the best 
performing sources (see discussion in section VI.C above). This is an 
emission level that the average of the performing sources could be 
expected to achieve in 99 of 100 future tests when operating under 
operating conditions identical to the compliance test conditions during 
which the emissions data were obtained. We estimate that this floor 
level is being achieved by 70% of sources and would reduce total 
chlorine emissions by 660 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We identified two potential beyond-the-floor techniques for control 
of total chlorine emissions: (1) Use of a wet scrubber; and (2) control 
of chlorine in the hazardous waste feed. For reasons discussed below, 
we are not proposing a beyond-the-floor standard for total chlorine.
    a. Use of Wet Scrubbing. We considered a beyond-the-floor standard 
of 1.3E-2 lbs total chlorine emissions attributable to the hazardous 
waste per million Btu heat input from the hazardous waste based on wet 
scrubbing to reduce emissions beyond the floor level by 50 percent. The 
national incremental annualized compliance cost for liquid fuel-fired 
boilers to meet this beyond-the-floor level rather than comply with the 
floor controls would be approximately $7.8 million and would provide an 
incremental reduction in total chlorine emissions beyond the MACT floor 
controls of 430 tons per year. We evaluated nonair quality health and 
environmental impacts and energy effects and determined that this 
beyond-the-floor option would increase both the amount of hazardous 
wastewater generated and water usage by approximately 3.2 billion 
gallons per year and would increase electricity usage by 30 million kW-
hours per year. Considering these impacts and a cost-effectiveness of 
approximately $18,000 per additional ton of total chlorine removed, we 
are not proposing a beyond-the-floor standard based on wet scrubbing.
    b. Feed Control of Chlorine in the Hazardous Waste. We evaluated 
additional feed control of chlorine in the hazardous waste as a beyond-
the-floor control technique to reduce floor emission levels by 20% to 
achieve a standard of 2.0E-2 lbs total chlorine emissions attributable 
to the hazardous waste per million Btu heat input from the hazardous 
waste. The national incremental annualized compliance cost for liquid 
fuel-fired boilers to meet this beyond-the-floor level rather than 
comply with the floor controls would be approximately $3.9 million and 
would provide an incremental reduction in total chlorine emissions 
beyond the MACT floor controls of 170 tons per year. Nonair quality 
health and environmental impacts and energy effects are not significant 
factors for feedrate control. We conclude that use of additional 
hazardous waste chlorine feedrate control would not be cost-effective 
at $23,000 per ton of total chlorine removed and are not proposing a 
beyond-the-floor standard based on this control technique.
    For the reasons discussed above, we propose a total chlorine 
standard for existing liquid fuel-fired boilers based on the floor 
level: 2.5E-2 lbs total chlorine emissions attributable to the 
hazardous waste per million Btu heat input from the hazardous waste.
3. What Is the Rationale for the MACT Floor for New Sources?
    The MACT floor for new sources for total chlorine would be 7.2E-4 
lbs total chlorine emissions attributable to the hazardous waste per 
million Btu heat input from the hazardous waste. This is an emission 
level that the single best performing source identified with the SRE/
Feed Approach could be expected to achieve in 99 of 100 future tests 
when operating under operating conditions identical to the compliance 
test conditions during which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated wet scrubbing as beyond-the-floor control for further 
reductions in total chlorine emissions to achieve a beyond-the-floor 
level of 3.6E-4 lbs total chlorine emissions attributable to the 
hazardous waste per million Btu heat input from the hazardous waste. 
The incremental annualized compliance cost for a new liquid fuel-fired 
boiler with an average gas flowrate to meet this beyond-the-floor 
level, rather than comply with the floor level, would be approximately 
$0.44 million and would provide an incremental reduction in total 
chlorine emissions of approximately 0.13 tons per year, for a cost-
effectiveness of $3.3 million per ton of total chlorine removed. We 
evaluated nonair quality health and environmental impacts and energy 
effects and determined that, for a new source with average an average 
gas flowrate, this beyond-the-floor option would increase both the 
amount of hazardous wastewater generated and water usage by 
approximately 140 million gallons per year and would increase 
electricity usage by 1.3 million kW-hours per year. After considering 
these impacts and cost-effectiveness, we conclude that a beyond-the-
floor standard based on wet scrubbing for new liquid fuel-fired boilers 
is not warranted.
    For the reasons discussed above, we propose a total chlorine 
standard for new sources based on the floor level: 7.2E-4 lbs total 
chlorine emissions attributable to the hazardous waste per million Btu 
heat input from the hazardous waste.

G. What Is the Rationale for the Proposed Standards for Carbon Monoxide 
or Hydrocarbons?

    To control emissions of organic HAP, existing and new sources would 
be required to comply with either a carbon monoxide standard of 100 
ppmv or a hydrocarbon standard of 10 ppmv.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Liquid fuel-fired boilers that burn hazardous waste are currently 
subject to RCRA standards that require compliance with either a carbon 
monoxide standard of 100 ppmv, or a hydrocarbon standard of 20 ppmv. 
Compliance is based on an hourly rolling average as measured with a 
CEMS. See Sec.  266.104(a). We are proposing today floor standards of 
100 ppmv for carbon monoxide or 10 ppmv for hydrocarbons.
    Floor control for existing sources is operating under good 
combustion practices including: (1) Providing adequate excess air with 
use of oxygen CEMS and feedback air input control; (2) providing 
adequate fuel/air mixing; (3) homogenizing hazardous waste fuels (such 
as by blending or size reduction) to control combustion upsets due to 
very high or very low volatile content wastes; (4) regulating waste and 
air feedrates to ensure proper combustion temperature and residence 
time; (5) characterizing waste prior to burning for combustion-related 
composition (including parameters such as heating value, volatile 
content, liquid waste viscosity, etc.); (6) ensuring the source is 
operated by qualified, experienced operators; and (7) periodic 
inspection and maintenance of combustion system components such as 
burners, fuel and air supply lines, injection nozzles, etc. Given that 
there are many interdependent parameters that affect combustion 
efficiency and thus carbon

[[Page 21292]]

monoxide and hydrocarbon emissions, we are not able to quantify ``good 
combustion practices.''
    All liquid fuel-fired boilers are currently complying with the RCRA 
carbon monoxide limit of 100 ppmv on an hourly rolling average. No 
boilers are complying with the RCRA hydrocarbon limit of 20 ppmv on an 
hourly rolling average.
    We propose a floor level for carbon monoxide level of 100 ppmv 
because it is a currently enforceable Federal standard. Although the 
best performing sources are achieving carbon monoxide levels below 100 
ppmv, it is not appropriate to establish a lower floor level because 
carbon monoxide is a surrogate for nondioxin/furan organic HAP. As 
such, lowering the carbon monoxide floor may not significantly reduce 
organic HAP emissions. In addition, it would be inappropriate to apply 
a MACT methodology to the carbon monoxide emissions from the best 
performing sources because those sources may not be able to replicate 
their emission levels. This is because there are myriad factors that 
affect combustion efficiency and, subsequently, carbon monoxide 
emissions. Extremely low carbon monoxide emissions cannot be assured by 
controlling only one or two operating parameters We note also that we 
used this rationale to establish a carbon monoxide standard of 100 ppmv 
for Phase I sources in the September 1999 Final Rule.
    We propose a floor level for hydrocarbons of 10 ppmv even though 
the currently enforceable standard is 20 ppmv because: (1) The two 
sources that comply with the RCRA hydrocarbon standard can readily 
achieve 10 ppmv; and (2) reducing hydrocarbon emissions within the 
range of 20 ppmv to 10 ppmv should reduce emissions of nondioxin/furan 
organic HAP. We do not apply a prescriptive MACT methodology to 
establish a hydrocarbon floor below 10 ppmv, however, because we have 
data from only two sources. In addition, we note that the hydrocarbon 
emission standard for Phase I sources established in the September 1999 
Final Rule is 10 ppmv also.
    There would be no incremental emission reductions associated with 
these floors because all sources are currently achieving the floor 
levels.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We considered beyond-the-floor levels for carbon monoxide and 
hydrocarbons based on use of better combustion practices but conclude 
that they may not be replicable by the best performing sources nor 
duplicable by other sources given that we cannot quantify good 
combustion practices. Moreover, as discussed above, we cannot ensure 
that lower carbon monoxide or hydrocarbon levels would significantly 
reduce emissions of nondioxin/furan organic HAP.
    Nonair quality health and environmental impacts and energy 
requirements are not significant factors for use of better combustion 
practices as beyond-the-floor control.
    For these reasons, we conclude that beyond-the-floor standards for 
carbon monoxide and hydrocarbons are not warranted for existing 
sources.
3. What Is the Rationale for the MACT Floor for New Sources?
    MACT floor for new sources would be the same as the floor for 
existing sources--100 ppmv for carbon monoxide and 10 ppmv for 
hydrocarbons--and based on the same rationale.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    As discussed in the context of beyond-the-floor considerations for 
existing sources, we considered beyond-the-floor standards for carbon 
monoxide and hydrocarbons for new sources based on use of better 
combustion practices. But we conclude that beyond the floor standards 
may not be replicable by the best performing sources nor duplicable by 
other sources given that we cannot quantify good combustion practices. 
Moreover, we cannot ensure that lower carbon monoxide or hydrocarbon 
levels would significantly reduce emissions of nondioxin/furan organic 
HAP.
    Nonair quality health and environmental impacts and energy 
requirements are not significant factors for use of better combustion 
practices as beyond-the-floor control.
    For these reasons, we are not proposing a beyond-the-floor standard 
for carbon monoxide and hydrocarbons.

H. What Is the Rationale for the Proposed Standard for Destruction and 
Removal Efficiency?

    To control emissions of organic HAP, existing and new sources would 
be required to comply with a destruction and removal efficiency (DRE) 
of 99.99% for organic HAP. For sources burning hazardous wastes F020, 
F021, F022, F023, F026, or F027, however, the DRE standard is 99.9999% 
for organic HAP.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Liquid fuel-fired boilers that burn hazardous waste are currently 
subject to RCRA DRE standards that require 99.99% destruction of 
designated principal organic hazardous constituents (POHCs). For 
sources that burn hazardous wastes F020, F021, F022, F023, F026, or 
F027, however, the DRE standard is 99.9999% destruction of designated 
POHCs. See Sec.  266.104(a).
    The DRE standard helps ensure that a combustor is operating under 
good combustion practices and thus minimizing emissions of organic HAP. 
Under the MACT compliance regime, sources would designate POHCs that 
are organic HAP or that are surrogates for organic HAP.
    We propose to establish the RCRA DRE standard as the floor for 
existing sources because it is a currently enforceable Federal 
standard. There would be no incremental costs or emission reductions 
associated with this floor because sources are currently complying with 
the standard.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We considered a beyond-the-floor level for DRE based on use of 
better combustion practices but conclude that it may not be replicable 
by the best performing sources nor duplicable by other sources given 
that we cannot quantify better combustion practices. Moreover, we 
cannot ensure that a higher DRE standard would significantly reduce 
emissions of organic HAP given that DRE measures the destruction of 
organic HAP present in the boiler feed rather than gross emissions of 
organic HAP. Although a source's combustion practices may be adequate 
to destroy particular organic HAP in the feed, other organic HAP that 
may be emitted as products of incomplete combustion may not be 
controlled by the DRE standard.\157\
---------------------------------------------------------------------------

    \157\ The carbon monoxide/hydrocarbon emission standard would 
control organic HAP that are products of incomplete combustion by 
also ensuring use of good combustion practices.
---------------------------------------------------------------------------

    For these reasons, and after considering nonair quality health and 
environmental impacts and energy requirements, we are not proposing a 
beyond-the-floor DRE standard for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
    We propose to establish the RCRA DRE standard as the floor for new 
sources because it is a currently enforceable Federal standard.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    Using the same rationale as we used to consider a beyond-the-floor 
DRE

[[Page 21293]]

standard for existing sources, we conclude that a beyond-the-floor DRE 
standard for new sources is not warranted. Consequently, after 
considering nonair quality health and environmental impacts and energy 
requirements, we are proposing the floor DRE standard for new sources.

XII. How Did EPA Determine the Proposed Emission Standards for 
Hazardous Waste Burning Hydrochloric Acid Production Furnaces?

    The proposed standards for existing and new hydrochloric acid 
production furnaces that burn hazardous waste are summarized in the 
table below. See proposed Sec.  63.1218.

  Proposed Standards for Existing and New Hydrochloric Acid Production
                                Furnaces
------------------------------------------------------------------------
                                         Emission standard\1\
 Hazardous air pollutant or  -------------------------------------------
          surrogate             Existing sources         New sources
------------------------------------------------------------------------
Dioxin and furan............  0.40 ng TEQ/dscm....  0.40 ng TEQ/dscm.
Hydrochloric acid and         14 ppmv or 99.9927%   1.2 ppmv or
 chlorine gas \2\.             System Removal        99.99937% System
                               Efficiency.           Removal Efficiency.
Carbon monoxide or            100 ppmv carbon       100 ppmv carbon
 hydrocarbons \3\.             monoxide or 10 ppmv   monoxide or 10 ppmv
                               hydrocarbons.         hydrocarbons.
Destruction and Removal       For existing and new sources, 99.99% for
 Efficiency.                   each principal organic hazardous
                               constituent (POHC). For sources burning
                               hazardous wastes F020, F021, F022, F023,
                               F026, or F027, however, 99.9999% for each
                               POHC.
------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen, dry basis.
\2\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\3\ Hourly rolling average. Hydrocarbons reported as propane.

A. What Is the Rationale for the Proposed Standards for Dioxin and 
Furan?

    The proposed standard for dioxin/furan for existing and new sources 
is 0.40 ng TEQ/dscm.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    The proposed MACT floor for existing sources is compliance with the 
proposed CO/HC emission standard and compliance with the proposed DRE 
standard.
    Hydrochloric acid production furnaces use wet scrubbers to remove 
hydrochloric acid from combustion gases to produce the hydrochloric 
acid product and to minimize residual emissions of hydrochloric acid 
and chlorine gas. Thus, dioxin/furan cannot be formed on particulate 
surfaces in the emission control device as can happen with 
electrostatic precipitators and fabric filters. Nonetheless, dioxin/
furan emissions from hydrochloric acid production furnaces can be very 
high. We have dioxin/furan emissions data for 18 test conditions 
representing 14 of the 17 sources. Dioxin/furan emissions range from 
0.02 ng TEQ/dscm to 6.8 ng TEQ/dscm.
    We investigated whether it would be appropriate to establish 
separate dioxin/furan standards for furnaces equipped with waste heat 
recovery boilers versus those without boilers. Ten of the 17 
hydrochloric acid production furnaces are equipped with boilers. We 
considered whether waste heat recovery boilers may be causing the 
elevated dioxin/furan emissions, as appeared to be the case for 
incinerators equipped with boilers. See 62 FR at 24220 (May 2, 1997) 
where we explain that heat recovery boilers preclude rapid temperature 
quench of combustion gases, thus allowing particle-catalyzed formation 
of dioxin/furan. The dioxin/furan data for hydrochloric acid production 
furnaces indicate, however, that furnaces with boilers have dioxin/
furan emissions ranging from 0.05 to 6.8 ng TEQ/dscm, while furnaces 
without boilers have dioxin/furan emissions ranging from 0.02 to 1.7 ng 
TEQ/dscm. Based on a statistical analysis of the data sets (see 
discussion in Part Two, Section II.E), we conclude that the dioxin/
furan emissions for furnaces equipped with boilers are not 
significantly different from dioxin/furan emissions for furnaces 
without boilers. Thus, we conclude that separate dioxin/furan emission 
standards are not warranted.
    We cannot identify or quantify a dioxin/furan control mechanism for 
these furnaces. Consequently, we conclude that establishing a floor 
emission level based on emissions from the best performing sources 
would not be appropriate because the best performing sources may not be 
able to replicate their emission levels, and other sources may not be 
able to duplicate those emission levels.
    We note, however, that dioxin/furan emissions can be affected by 
the furnace's combustion efficiency. Operating under poor combustion 
conditions can generate dioxin/furan and organic precursors that may 
contribute to post-combustion dioxin/furan formation. Because we cannot 
quantify a dioxin/furan floor level and because hydrochloric acid 
production furnaces are currently required to operate under good 
combustion practices by RCRA standards for carbon monoxide/hydrocarbons 
and destruction and removal efficiency, we identify those RCRA 
standards as the proposed MACT floor. See Sec.  266.104 requiring 
compliance with destruction and removal efficiency and carbon monoxide/
hydrocarbon emission standards.\158\ We also find, as required by CAA 
section 112(h)(1), that these proposed standards are consistent with 
section 112(d)'s objective of reducing emissions of these HAP to the 
extent achievable.
---------------------------------------------------------------------------

    \158\ Section 266.104 requires compliance with a carbon monoxide 
limit of 100 ppmv or a hydrocarbon limit of 20 ppmv, while we are 
proposing today a carbon monoxide limit of 100 ppmv or a hydrocarbon 
limit of 10 ppmv (see Section XII.H in the text). Although today's 
proposed hydrocarbon limit is more stringent than the current limit 
for hydrochloric acid production furnaces, all sources chose to 
comply with the 100 ppmv carbon monoxide limit.
---------------------------------------------------------------------------

    We also request comment on an alternative MACT floor expressed as a 
dioxin/furan emission concentration. Although it would be inappropriate 
to identify a floor concentration based on the average emissions of the 
best performing sources as discussed above, we could identify the floor 
as the highest emission concentration from any source in our data base, 
after considering emissions variability. Under this approach, the 
highest emitting source could be expected to achieve the floor 99 out 
of 100 future tests when

[[Page 21294]]

operating under the same conditions as it did when the emissions data 
were obtained. A floor that is expressed as a dioxin/furan emission 
level would prevent sources from emitting at levels higher than the 
(currently) worst-case source (actually, the worst-case performance 
test result) currently emits. We specifically request comment on this 
alternative MACT floor.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated use of an activated carbon bed (preceded by gas 
reheating to above the dewpoint) as beyond-the-floor control for 
dioxin/furan. Carbon beds can achieve greater than 99% reduction in 
dioxin/furan emissions.\159\ We considered alternative beyond-the-floor 
levels of 0.40 ng TEQ/dscm and 0.20 ng TEQ/dscm.
---------------------------------------------------------------------------

    \159\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume V: Emissions Estimates and Engineering 
Costs,'' March 2004, Chapter 4.
---------------------------------------------------------------------------

    The incremental annualized cost of a beyond-the-floor emission 
level of 0.40 ng TEQ/dscm would be $1.9 million and would provide an 
incremental reduction in dioxin/furan emissions of 2.3 grams TEQ per 
year, for a cost-effectiveness of $0.83 million per gram TEQ 
removed.\160\ A beyond-the-floor emission level of 0.20 ng TEQ/dscm 
would provide very little incremental emissions reduction--0.1 grams 
TEQ per year--at additional costs. We evaluated nonair quality health 
and environmental impacts and energy effects and determined that this 
beyond-the-floor option would increase the amount of hazardous 
wastewater generated by 210 tons per year, and would increase 
electricity usage by 1.8 million kW-hours per year and natural gas 
consumption by 96 trillion Btu per year.
---------------------------------------------------------------------------

    \160\ Please note that, under the proposed floor level, sources 
would not incur retrofit costs or achieve dioxin/furan emissions 
reductions because they currently comply with the floor controls 
under current RCRA regulations at 40 CFR 266.104.
---------------------------------------------------------------------------

    We judge that the cost to achieve a beyond-the-floor standard of 
0.40 ng TEQ/dscm is warranted given our special concern about dioxin/
furan. Dioxin/furan 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/
furan for priority MACT control in CAA section 112(c)(6). See S. Rep. 
No. 128, 101st Cong. 1st Sess. at 154-155. In addition, we note that 
the beyond-the-floor emission level of 0.40 ng TEQ/dscm is consistent 
with historically controlled levels under MACT for hazardous waste 
incinerators and cement kilns, and Portland cement plants. See 
Sec. Sec.  63.1203(a)(1), 63.1204(a)(1), and 63.1343(d)(3). Also, EPA 
has determined previously in the 1999 Hazardous Waste Combustor MACT 
final rule that dioxin/furan in the range of 0.40 ng TEQ/dscm or less 
are necessary for the MACT standards to be considered generally 
protective of human health under RCRA (using the 1985 cancer slope 
factor), thereby eliminating the need for separate RCRA standards under 
the authority of RCRA section 3005(c)(3) and 40 CFR 270.10(k). Finally, 
we note that this decision is not inconsistent with EPA's decision not 
to promulgate beyond-the-floor standards for dioxin/furan for hazardous 
waste burning lightweight aggregate kilns, cement kilns, and 
incinerators at cost-effectiveness values in the range of $530,000 to 
$827,000 per additional gram of dioxin/furan TEQ removed. See 64 FR at 
52892, 52876, and 52961. In those cases, EPA determined that 
controlling dioxin/furan emissions from a level of 0.40 ng TEQ/dscm to 
a beyond-the-floor level of 0.20 ng TEQ/dscm was not warranted because 
dioxin/furan levels below 0.40 ng TEQ/dscm are generally considered to 
be below the level of health risk concern.
    For these reasons, we believe that proposing a beyond-the-floor 
standard of 0.40 ng TEQ/dscm is warranted notwithstanding the nonair 
quality health and environmental impacts and energy effects identified 
above and costs of approximately $0.83 million per additional gram of 
dioxin/furan TEQ removed. We specifically request comment on our 
decision to propose this beyond-the-floor standard.
3. What Is the Rationale for the MACT Floor for New Sources?
    MACT floor for new sources is the same as for existing sources 
under the same rationale: compliance with the carbon monoxide/
hydrocarbon emission standard and compliance with the destruction and 
removal efficiency standard.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    As for existing sources, we evaluated use of an activated carbon 
bed as beyond-the-floor control for new sources to achieve an emission 
level of 0.40 ng TEQ/dscm. We estimate that the incremental annualized 
cost for a new hydrochloric acid production furnace with average gas 
flowrate to reduce dioxin/furan emissions at the floor of 0.68 ng TEQ/
dscm \161\ to achieve a beyond-the-floor emission level of 0.40 ng TEQ/
dscm would be $0.15 million. These controls would provide an 
incremental reduction in dioxin/furan emissions of 0.66 grams TEQ per 
year, for a cost-effectiveness of $230,000 per gram TEQ removed. We 
evaluated nonair quality health and environmental impacts and energy 
effects and determined that, for a new source with an average gas 
flowrate, this beyond-the-floor option would increase the amount of 
hazardous wastewater generated by 9 tons per year, and would increase 
electricity usage by 0.14 million kW-hours per year and natural gas 
consumption by 9.2 trillion Btu per year.
---------------------------------------------------------------------------

    \161\ We estimate beyond-the-floor control costs assuming a new 
source emits the highest levels likely under floor control based on 
compliance with the carbon monoxide and destruction and removal 
efficiency standards.
---------------------------------------------------------------------------

    We judge that the cost to achieve a beyond-the-floor standard of 
0.40 ng TEQ/dscm is warranted given our special concern about dioxin/
furan. Dioxin/furan 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 our dioxin/
furan for priority MACT control in CAA section 112(c)(6). See S. Rep. 
No. 128, 101st Cong. 1st Sess. at 154-155. In addition, we note that 
the beyond-the-floor standard of 0.40 ng TEQ/dscm is consistent with 
historically controlled levels under MACT for hazardous waste 
incinerators and cement kilns, and Portland cement plants. See 
Sec. Sec.  63.1203(a)(1), 63.1204(a)(1), and 63.1343(d)(3). Also, EPA 
has determined previously in the 1999 Hazardous Waste Combustor MACT 
final rule that dioxin/furan in the range of 0.40 ng TEQ/dscm or less 
are necessary for the MACT standards to be considered generally 
protective of human health under RCRA (using the 1985 cancer slope 
factor), thereby eliminating the need for separate RCRA standards under 
the authority of RCRA section 3005(c)(3) and 40 CFR 270.10(k).
    For these reasons, we believe that proposing a beyond-the-floor 
standard of 0.40 ng TEQ/dscm is warranted notwithstanding the nonair 
quality health and environmental impacts and energy effects identified 
above and costs of approximately $0.23 million per additional gram of 
dioxin/furan TEQ removed. We specifically request comment on our 
decision to propose this beyond-the-floor standard.

[[Page 21295]]

B. What Is the Rationale for the Proposed Standards for Mercury, 
Semivolatile Metals, and Low Volatile Metals?

    We propose to require compliance with the total chlorine standard 
as a surrogate for the mercury, semivolatile metals, and low volatile 
metals standards.
    As discussed above, hydrochloric acid production furnaces use wet 
scrubbers to remove hydrochloric acid from combustion gases to produce 
the hydrochloric acid product and to minimize residual emissions of 
hydrochloric acid and chlorine gas. Wet scrubbers also remove metal 
HAP, including mercury, from combustion gases. To minimize 
contamination of hydrochloric acid product with metals, hydrochloric 
acid production furnaces generally feed hazardous waste with low levels 
of metal HAP. Moreover, the wet scrubbers used to recover the 
hydrochloric acid product and minimize residual emissions of 
hydrochloric acid and chlorine gas also control emissions of metal HAP 
to very low levels. Based on emissions testing within the range of 
normal emissions (i.e., not compliance test, maximum allowed 
emissions), hydrochloric acid production furnaces emit mercury at 
levels from 0.1 to 0.4 [mu]g/dscm, semivolatile metals at levels from 
0.1 to 4.1 [mu]g/dscm, and low volatile metals at levels from 0.1 to 43 
[mu]g/dscm.162, 163
---------------------------------------------------------------------------

    \162\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards,'' 
March 2004, Chapter 2.
    \163\ Except that one source emitted 330 [mu]g/dscm low volatile 
metals and 0.043 gr/dscf particulate matter during compliance 
testing. This source apparently detuned the acid gas absorber and 
other acid gas control equipment given that it achieved less than 
99% system removal efficiency for total chlorine and had total 
chlorine emissions of 500 ppmv. This source would not be allowed to 
operate under these conditions under today's proposed rule: 14 ppmv 
total chlorine emission limit, or 99.9927 system removal efficiency. 
Thus, under the proposed rule, emissions of low volatile metals and 
particulate matter would be substantially lower.
---------------------------------------------------------------------------

    We also note that these sources emit low levels of particulate 
matter. Compliance test, maximum allowable emissions of particulate 
matter range from 0.001 to 0.013 gr/dscf.
    Because wet scrubbers designed to recover the hydrochloric acid 
product and control residual emissions of hydrogen chloride and 
chlorine gas also control emissions of mercury, and semivolatile and 
low volatile metals (including nonenumerated metals), use of MACT wet 
scrubbers to comply with the proposed total chlorine standard discussed 
below will also ensure MACT control of metal HAP. Accordingly, we 
propose to use the total chlorine standard as a surrogate for the 
mercury, semivolatile metals, and low volatile metals standards.

C. What Is the Rationale for the Proposed Standards for Total Chlorine?

    The proposed standards for total chlorine are 14 ppmv or 99.9927 
percent total chlorine system removal efficiency (SRE) for existing 
sources and 1.2 ppmv or 99.99937 percent total chlorine SRE for new 
sources. A source may elect to comply with either standard.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    The proposed MACT floor for existing sources is compliance with 
either a total chlorine emission level of 14 ppmv or a total chlorine 
SRE of 99.9927 percent.
    Hydrochloric acid production furnaces use wet scrubbers to remove 
hydrochloric acid from combustion gases to produce the hydrochloric 
acid product and to minimize residual emissions of hydrochloric acid 
and chlorine gas. We have compliance test, maximum allowable total 
chlorine emissions data for all 17 hydrochloric acid production 
furnaces. Total chlorine emissions range from 0.4 to 500 ppmv, and 
total chlorine system removal efficiencies (SRE) range from 98.967 to 
99.9995 percent.
    As discussed in Section VI.C above, control of the feedrate of 
chlorine in hazardous waste fed to the furnace is not an appropriate 
MACT emission control technique because hydrochloric acid production 
furnaces are designed to produce hydrochloric acid from chlorinated 
feedstocks. Consequently, the approaches we normally use to identify 
the best performing sources--SRE/Feed Approach or Emissions Approach--
are not appropriate because they directly or indirectly consider 
chlorine feedrate. More simply, limiting feedrate means not producing 
the intended product, a result inconsistent with MACT. See 2 
Legislative History at 3352 (House Report) (``MACT is not intended to * 
* * drive sources to the brink of shutdown''). To avoid this concern, 
we identify a floor SRE, and provide an alternative floor as a total 
chlorine emission limit based on floor SRE and the highest chlorine 
feedrate for any source in the data base. By using the highest chlorine 
feedrate to calculate the alternative total chlorine emission limit, we 
ensure that feedrate control (i.e., nonproduction of product) is not a 
factor in identifying the proposed MACT floor. The alternative total 
chlorine emission limit would require a source that may not be 
achieving floor SRE to achieve total chlorine emission levels no 
greater than the level that would be emitted by any source achieving 
floor SRE.
    The floor SRE is 99.9927 percent. It is calculated from the five 
best SREs, and considers emissions variability. Floor SRE is an SRE 
that the average of the performing sources could be expected to achieve 
in 99 of 100 future tests when operating under conditions identical to 
the compliance test conditions during which the emissions data were 
obtained. We estimate that this SRE is being achieved by 29% of 
sources.
    The alternative floor emission limit is 14 ppmv, and is the 
emission level that the source with the highest chlorine feedrate--
2.9E+8 [mu]g/dscm--would achieve when achieving 99.9927 percent SRE.
    Approximately 24% of sources are achieving the alternative floor 
levels, and these floor levels would reduce total chlorine emissions by 
145 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We evaluated improved design, operation, and maintenance of 
existing scrubbers to achieve a beyond-the-floor emission level of 7 
ppmv for total chlorine for existing sources, assuming a 50% reduction 
in emissions from the floor level.
    The national annualized compliance cost for hydrochloric acid 
production furnaces to comply with this beyond-the-floor standard would 
be $0.25 million, and emissions of total chlorine would be reduced by 3 
tons per year. The cost-effectiveness of this beyond-the-floor standard 
would be $76,000 per ton of total chlorine removed.
    We evaluated nonair quality health and environmental impacts and 
energy effects and determined that this beyond-the-floor option would 
increase both the amount of hazardous wastewater generated and water 
usage by approximately 82 million gallons per year and would increase 
electricity usage by 0.34 million kW-hours per year. Generation of 
nonwastewater hazardous waste would decrease by 7 tons per year. 
Considering these impacts and cost-effectiveness as well, we conclude 
that a beyond-the-floor standard for existing sources would not be 
warranted.
    For these reasons, we propose a floor total chlorine standard of 14 
ppmv or 99.9927% SRE for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
    The proposed MACT floor for new sources is compliance with either a 
total chlorine emission level of 1.2 ppmv or

[[Page 21296]]

a total chlorine SRE of 99.99937 percent. We use the same rationale for 
identifying alternative floors for new sources as discussed above in 
the context of existing sources.
    The new source floor SRE is the SRE that the single best performing 
source (i.e, source with the best SRE) could be expected to achieve in 
99 of 100 future tests when operating under conditions identical to the 
compliance test conditions during which the emissions data were 
obtained. The new source floor alternative emission limit is an 
emission level that the source with the highest chlorine feedrate--
2.9E+8 [mu]g/dscm--would achieve when achieving 99.99937 percent SRE.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    We evaluated a beyond-the-floor standard for new sources of 0.60 
ppmv based on achieving a 50 percent reduction in emissions by 
improving the design/operation/maintenance of the wet scrubber. The 
incremental annualized cost for a new solid fuel-fired boiler with 
average gas flowrate to meet a beyond-the-floor level of 0.60 ppmv 
would be approximately $0.15 million and would provide an incremental 
reduction in total chlorine emissions of 0.07 tons per year, for a 
cost-effectiveness of $2.1 million per ton of total chlorine removed.
    We evaluated nonair quality health and environmental impacts and 
energy effects and determined that, for a new source with average gas 
flowrate, this beyond-the-floor option would increase both the amount 
of hazardous wastewater generated and water usage by approximately 26 
million gallons per year and would increase electricity usage by 0.25 
million kW-hours per year. Considering these impacts and cost-
effectiveness as well, we conclude that a beyond-the-floor standard for 
new sources would not be warranted.
    For the reasons discussed above, we propose a total chlorine 
standard of 1.2 ppmv or a total chlorine SRE of 99.99937 percent for 
new sources.

D. What Is the Rationale for the Proposed Standards for Carbon Monoxide 
or Hydrocarbons?

    To control emissions of organic HAP, existing and new sources would 
be required to comply with either a carbon monoxide standard of 100 
ppmv or a hydrocarbon standard of 10 ppmv.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Hydrochloric acid production furnaces that burn hazardous waste are 
currently subject to RCRA standards that require compliance with either 
a carbon monoxide standard of 100 ppmv, or a hydrocarbon standard of 20 
ppmv. Compliance is based on an hourly rolling average as measured with 
a CEMS. See Sec.  266.104(a). All hydrochloric acid production furnaces 
have elected to comply with the 100 ppmv carbon monoxide standard. We 
propose floor standards of 100 ppmv for carbon monoxide or 10 ppmv for 
hydrocarbons for the same reasons discussed above in the context of 
liquid fuel-fired boilers.
    There would be no incremental emission reductions associated with 
these floors because sources are currently achieving the carbon 
monoxide standard.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    Our considerations for beyond-the-floor standards for existing 
hydrochloric acid production furnaces are identical to those discussed 
above for existing liquid fuel-fired boilers. For the reasons discussed 
above in the context of liquid fuel-fired boilers, we conclude that 
beyond-the-floor standards for carbon monoxide and hydrocarbons for 
existing hydrochloric acid production furnaces are not warranted.
3. What Is the Rationale for the MACT Floor for New Sources?
    MACT floor for new sources would be the same as the floor for 
existing sources--100 ppmv for carbon monoxide and 10 ppmv for 
hydrocarbons--and based on the same rationale.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    Our considerations for beyond-the-floor standards for new 
hydrochloric acid production furnaces are identical to those discussed 
above for new liquid fuel-fired boilers. For the reasons discussed 
above in the context of liquid fuel-fired boilers, we conclude that 
beyond-the-floor standards for carbon monoxide and hydrocarbons for new 
hydrochloric acid production furnaces are not warranted.

E. What Is the Rationale for the Proposed Standard for Destruction and 
Removal Efficiency?

    To control emissions of organic HAP, existing and new sources would 
be required to comply with a destruction and removal efficiency (DRE) 
of 99.99% for organic HAP. For sources burning hazardous wastes F020, 
F021, F022, F023, F026, or F027, however, the DRE standard is 99.9999% 
for organic HAP.
1. What Is the Rationale for the MACT Floor for Existing Sources?
    Hydrochloric acid production furnaces that burn hazardous waste are 
currently subject to RCRA DRE standards that require 99.99% destruction 
of designated principal organic hazardous constituents (POHCs). For 
sources that burn hazardous wastes F020, F021, F022, F023, F026, or 
F027, however, the DRE standard is 99.9999% destruction of designated 
POHCs. See Sec.  266.104(a).
    The DRE standard helps ensure that a combustor is operating under 
good combustion practices and thus minimizing emissions of organic HAP. 
Under the MACT compliance regime, sources would designate POHCs that 
are organic HAPs or that are surrogates for organic HAPs.
    We propose to establish the RCRA DRE standard as the floor for 
existing sources because it is a currently enforceable Federal 
standard. There would be no incremental emission reductions associated 
with this floor because sources are currently complying with the 
standard.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
    We considered a beyond-the-floor level for DRE based on use of 
better combustion practices but conclude that it may not be replicable 
by the best performing sources nor duplicable by other sources given 
that we cannot quantify better combustion practices. Moreover, we 
cannot ensure that a higher DRE standard would significantly reduce 
emissions of organic HAP given that DRE measures the destruction of 
organic HAP present in the boiler feed rather than gross emissions of 
organic HAP. Although a source's combustion practices may be adequate 
to destroy particular organic HAP in the feed, other organic HAP may be 
emitted as products of incomplete combustion.
    For these reasons, and after considering nonair quality health and 
environmental impacts and energy requirements, we are not proposing a 
beyond-the-floor DRE standard for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
    We propose to establish the RCRA DRE standard as the floor for new 
sources because it is a currently enforceable Federal standard.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
    Using the same rationale as we used to consider a beyond-the-floor 
DRE

[[Page 21297]]

standard for existing sources, we conclude that a beyond-the-floor DRE 
standard for new sources is not warranted. Consequently, after 
considering nonair quality health and environmental impacts and energy 
requirements, we are proposing the floor DRE standard for new sources.

XIII. What Is the Rationale for Proposing an Alternative Risk-Based 
Standard for Total Chlorine in Lieu of the MACT Standard?

    Under authority of CAA section 112(d)(4), we propose standard 
procedures to allow you to establish a risk-based emission limit for 
total chlorine in lieu of compliance with the section 112(d)(2) MACT 
emission standard. See proposed Sec.  63.1215. The risk-based approach 
would be applicable to all hazardous waste combustors except 
hydrochloric acid production furnaces. Because we are proposing to use 
the MACT standard for total chlorine as a surrogate to control metal 
HAP for the hydrogen chloride production furnace source category, we 
cannot allow any variance from the standard. For the other hazardous 
waste combustor source categories, we are proposing the section 
112(d)(4) standard as an alternative to the MACT standard. Sources 
could choose which of these two standards they would prefer to apply.
    The alternative risk-based emission limit for total chlorine would 
be based on national exposure standards established by EPA that ensure 
protection of public health with an ample margin of safety. The 
standard would consist of a nationally-applicable, uniform algorithm 
that would be used to establish site-specific emission limitations 
based on site-specific input from each source choosing to use this 
approach. Thus, these standards would provide a uniform level of risk 
reduction, consistent with the requirement of section 112(d)(4) that 
EPA establish ``emission standards'', i.e., a requirement established 
by EPA which limits quantity, rate or concentration of air emissions 
(see CAA section 302(k)).
    We also request comment on an alternative approach to implement 
section 112(d)(4) for cement kilns in which we establish a national 
risk-based emission standard for total chlorine that would be 
applicable to all cement kilns. Under this approach, EPA would issue a 
single total chlorine emission standard using an emission level that 
meets our national exposure standards if each cement kiln were to emit 
at that level.
    We believe that most hazardous waste combustors are likely to 
consider establishing risk-based standards for total chlorine because 
the MACT standards proposed today are more stringent, and in some cases 
substantially more stringent, than currently applicable standards 
(e.g., the total chlorine standard for incinerators is currently 77 
ppmv while we propose today a MACT standard of 1.4 ppmv).

A. What Is the Legal Authority To Establish Risk-Based Standards?

    Under the authority of section 112(d)(4), the Administrator may 
establish emission standards based on risk, in lieu of the technology-
based MACT standards, when regulating HAP for which health threshold 
levels have been established. Under section 112(d)(4), Congress gave 
EPA the discretion to consider the health threshold of any HAP and to 
use that health threshold, with an ample margin of safety, to set 
emission standards for the source category or subcategory. In the 
legislative history accompanying this provision, the Senate Report 
stated,

    ``To avoid expenditures by regulated entities that secure no 
public health or environmental benefit, the Administrator is given 
discretionary authority to consider the evidence for a health 
threshold higher than MACT at the time the standard is under review. 
The Administrator is not required to take such factors into account; 
that would jeopardize the standard-setting schedule imposed under 
this section with the kind of lengthy study and debate that has 
crippled the current program. But where health thresholds are well 
established, for instance in the case of ammonia, and the pollutant 
presents no risk of other adverse health effects, the Administrator 
may use the threshold with an ample margin of safety (and not 
considering cost) to set emissions limitations for sources in the 
category or subcategory.'' (S. Rep. No. 228, 101st Cong. 1st Sess. 
at 171 (1989); see also id. at 175-176 (1989).)

    EPA has previously used section 112(d)(4) authority in the 
Industrial Boiler and Process Heater MACT Final Rule signed Feb. 26, 
2004, the Pulp and Paper MACT Phase II (66 FR 3180, January 12, 2001) 
and the Lime Manufacturing MACT (69 FR 394, January 5, 2004), and has 
proposed to use it in a different manner in several other MACT 
rulemakings (e.g., the Reciprocating Internal Combustion Engine MACT 
(67 FR 77830, December 19, 2002).\164\ The approach we propose today is 
nearly identical to the approach EPA recently adopted for the 
Industrial Boiler and Process Heater MACT source category, which allows 
a source to establish a site-specific risk-based emission limit for 
threshold HAP using prescribed procedures. This approach differs from 
the previous MACT rules where EPA simply determined, on a national 
basis, what level of exposure from each source in the category would be 
protective of public health with an ample margin of safety, and did not 
pose significant adverse environmental impacts. This previous approach 
resulted in a determination that no standard was necessary because no 
source in the category could exceed such a risk-based standard. Today's 
proposal varies in that the level of protection afforded by the 
standard is uniform, but the limits for individual sources differ due 
to site-specific factors. As explained later in this section of the 
preamble, EPA is, however, also considering for cement kilns applying 
the single national standard approach adopted in earlier rules.
---------------------------------------------------------------------------

    \164\ The Agency also proposed to use Section 112(d)(4) 
authority in two other MACT rulemakings--the Combustion Turbine MACT 
(68 FR 1888, January 14, 2003), and the Chlorine Production MACT (67 
FR 44671)--but determined that MACT standards for those source 
categories are not warranted and delisted the source categories from 
the section 112(c) list of major sources pursuant to the authority 
in section 112(c)(9).
---------------------------------------------------------------------------

B. What Is the Rationale for the National Exposure Standards?

    We identify as national exposure standards threshold levels that 
are protective of human health from both chronic and acute exposure. In 
addition, because EPA has discretion whether or not to promulgate risk-
based standards pursuant to section 112(d)(4), we would not allow an 
alternative standard where emission levels may result in adverse 
environmental effects that would otherwise be reduced or eliminated. We 
would not issue the alternative standard even though it may be shown 
that emissions do not approach or exceed levels requisite to protect 
public health with an ample margin of safety because we believe the 
statute requires that we consider effects on terrestrial animals, 
plants, and aquatic ecosystems in addition to public health in 
establishing a standard pursuant to section 112(d)(4). See S. Rep. 228 
at 176: ``Employing a health threshold or safety level rather than the 
MACT criteria to set standards shall not result in adverse 
environmental effects which would otherwise be reduced or eliminated.''
1. What Are the Human Health Threshold Levels?
    a. Chronic Exposure. Hydrogen chloride is corrosive to the eyes, 
skin, and mucous membranes. Chronic exposure may cause gastritis, 
bronchitis, dermatitis, and dental discoloration and erosion. Chronic 
exposure to chlorine gas can cause respiratory effects

[[Page 21298]]

including eye and throat irritation and airflow obstruction. See 
discussion in Part One, Section I.E of this preamble.
    Given that neither hydrogen chloride nor chlorine gas is known to 
produce a carcinogenic response,\165\ we use reference air 
concentrations (RfC) to assess the likelihood of non-cancer health 
effects in humans. The RfC is an estimate of a continuous inhalation 
exposure to the human population, including sensitive subgroups, that 
is likely to be without an appreciable risk of deleterious effects over 
a lifetime. We use an RfC for hydrogen chloride of 20 [mu]g/m\3\, as 
presented in EPA's Integrated Risk Information System (IRIS). We 
propose to use an RfC for chlorine gas of 0.2 [mu]g/m\3\ based on a 
provisional assessment prepared by EPA on inhalation hazards from 
chlorine.\166\ This is the same as the value for chlorine used by the 
State of California's Office of Environmental Health Hazard Assessment, 
which they refer to as a chronic ``Reference Exposure Level'' (REL). 
Because RfCs can change over time based on new information, the rule 
would require you to use the current RfC value found at http://epa.gov/ttn/atw/toxsource/summary.html.
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    \165\ EPA conducted an assessment of the carcinogenicity of 
chlorine gas and concluded that it is not likely to be a human 
carcinogen (see EPA's June 22, 1999 Risk Assessment Issue Paper for 
Derivation of a Provisional Chronic Inhalation RfC for Chlorine, 
p.12). The International Agency for Research on Cancer (IARC) 
concluded that hydrochloric acid is not classifiable as to its 
carcinogenicity to humans (see IARC Monographs, Vol. 54: 
Occupational Exposures to Mists and Vapours from Strong Inorganic 
Acids; and Other Industrial Chemicals (1992) p.189).
    \166\ See EPA's externally peer-reviewed ``Risk Assessment Issue 
Paper for Derivation of a Provisional Chronic Inhalation RfC for 
Chlorine'' (June 22, 1999) that can be found in the docket for 
today's proposal.
---------------------------------------------------------------------------

    We considered how to account for the fact that chlorine gas 
photolyzes in the atmosphere in bright sunlight to chlorine ions and 
then quickly reacts with hydrogen or methane to form hydrogen chloride. 
The half-life of chlorine due to photolysis in bright sunlight is 
estimated to be 10 minutes.\167\ Nonetheless, this is generally 
sufficient time for the plume to reach nearby ground-level receptors 
without significant transformation. In addition, such transformation is 
possible only a portion of the time. Photolysis does not occur at night 
and is reduced on overcast or cloudy days. Generally speaking, the rate 
of photolysis depends on the particular wavelength and intensity of 
solar radiation reaching the earth's surface which varies greatly 
depending on the solar angle which changes with the time of day, the 
season of the year, and the latitude at a given location. While the 
ideal approach would be explicit modeling of photolysis rates as a 
function of solar insolation, sky conditions, absorption cross-section, 
quantum yield, and subsequent transformation to hydrogen chloride, to 
our knowledge no such regulatory air dispersion model currently exists.
---------------------------------------------------------------------------

    \167\ As determined by a modeling analysis done by the Air 
Pollution Research Center at the University of California at 
Riverside, as reported in a California Air Resources Board fact 
sheet, ``Toxic Air Contaminant Identification List Summaries--ARB/
SSD/SES,'' p. 231, September 1997. See also http://www.arb.ca.gov/toxics/tac/factshts/chlorine.pdf.
---------------------------------------------------------------------------

    Because it is reasonable to believe that receptors will be exposed 
to chlorine gas before appreciable transformation occurs due to the 
variability and complexity of the transformation and the fact that 
chlorine gas is considerably more toxic than hydrogen chloride, we 
conclude that, for the purpose of protection of public health, it is 
prudent to assume that chlorine gas is not transformed to hydrogen 
chloride.
    b. Acute Threshold Levels. Short-term exposure to hydrogen chloride 
may cause eye, nose, and respiratory tract irritation and inflamation 
and pulmonary edema. Short-term exposure to high levels of chlorine gas 
can result in chest pain, vomiting, toxic pneumonitis, and pulmonary 
edema. At lower levels, chlorine gas is a potent irritant to the eyes, 
the upper respiratory tract, and lungs. See Part One, Section I.E. 
Please note that, although we discuss here how we would consider acute 
exposure, we conclude below that you need not assess acute exposure to 
establish an emission limit for total chlorine. See discussion in 
Section B.2.e.
    To assess effects from acute exposure, we would use the acute 
exposure guideline level (AEGL). AEGL toxicity values are estimates of 
adverse health effects due to a single exposure lasting 8 hours or 
less. Consensus toxicity values for effects of acute exposures have 
been developed by several different organizations. EPA, in conjunction 
with the National Research Council and National Academy of Sciences, is 
in the process of setting acute exposure guideline levels. A national 
advisory committee organized by EPA has developed AEGLs for priority 
chemicals for 10-minute, 30-minute, 1-hour, 4-hour, and 8-hour airborne 
exposures. They have also determined for each exposure duration the 
levels of these chemicals that will protect against notable discomfort 
(AEGL-1), serious effects (AEGL-2), and life-threatening effects or 
death (AEGL-3).\168\ To be protective of public health, we propose to 
use the AEGL-1 values to assess acute exposure: 2.7 mg/m\3\ (1.8 ppm) 
for hydrogen chloride, and 1.4 mg/m\3\ (0.5 ppm) for chlorine gas.\169\ 
Airborne concentrations of a substance above the AEGL-1 could cause 
notable discomfort, irritation, or certain asymptomatic nonsensory 
effects in the general population, including susceptible individuals. 
Please note, however, that airborne concentrations below the AEGL-1 
could produce mild odor, taste, or other sensory irritations. Effects 
above the AEGL-1 (but below the AEGL-2) are not disabling and are 
transient and reversible upon cessation of exposure.
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    \168\ The full definitions of the AEGL values are more nuanced. 
AEGL 1: The airborne concentration of a substance above which it is 
predicted that the general population, including susceptible 
individuals, could experience notable discomfort, irritation, or 
certain asymptomatic nonsensory effects. However, the effects are 
not disabling and are transient and reversible upon cessation of 
exposure. AEGL 2: The airborne concentration of a substance above 
which it is predicted that the general population, including 
susceptible individuals, could experience irreversible or other 
serious, long-lasting adverse health effects or an impaired ability 
to escape. AEGL 3: The airborne concentration of a substance above 
which it is predicted that the general population, including 
susceptible individuals, could experience life-threatening health 
effects or death.
    \169\ For hydrogen chloride and chlorine gas (individually), the 
AEGL-1 values for 10-minute, 30-minute, 1-hour, and 8-hour exposures 
are the same. Therefore, when comparing predicted ambient levels of 
exposure to the AEGL-1 value, we believe it is reasonable to 
evaluate maximum 1-hour ground level concentrations.
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2. What Exposures Would You Be Required to Assess?
    We discuss below the following issues: (1) Use of the Hazard Index 
to assess exposure to both hydrogen chloride and chlorine gas; (2) 
exposure to emissions of respiratory irritant HAP other than hydrogen 
chloride and chlorine gas; (3) exposure to emissions of respiratory 
irritant HAP from collocated sources; (4) exposure to ambient 
background levels of respiratory irritant HAP; and (5) our conclusion 
that acute exposure need not be assessed to establish emission limits 
because the Hazard Index for chronic exposure is expected to be higher 
in all situations.
    a. Hazard Index. Noncancer risk assessments typically use a metric 
called the Hazard Quotient (HQ) to assess risks of exposures to 
noncarcinogens. The HQ is the ratio of a receptor's potential exposure 
(or modeled concentration) to the health reference value or threshold 
level (e.g., RfC or AEGL) for an individual pollutant. HQ values less 
than 1.0 indicate that exposures are below the

[[Page 21299]]

health reference value or threshold level and, therefore, that such 
exposures are without appreciable risk of adverse effects in the 
exposed population. HQ values above 1 do not necessarily imply that 
adverse effects will occur, but that the likelihood of such effects in 
a given population increases as HQ values exceed 1.0.\170\
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    \170\ See US EPA Glossary of Key Terms for National Air Toxics 
Assessment, at http://www.epa.gov//ttn/atw/nata/gloss1.html.
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    When the risk of noncancer effects from exposure to more than one 
pollutant to the same target organ must be assessed, the effects are 
generally considered to be additive and the HQ values for each 
pollutant are summed to form an analogous metric called the Hazard 
Index (HI). Assuming additivity, HI values less than 1.0 indicate that 
exposures to the mixtures are likely to be without appreciable risk of 
adverse effects in the exposed population. HI values above 1.0 do not 
necessarily imply that adverse effects from exposure to the mixture 
will occur, but that the likelihood of such effects in a given 
population increases as HI values exceed 1.0.
    For purposes of establishing risk-based emission limits for total 
chlorine, we propose to allow a maximum HI value of not greater than 
1.0.
    b. Exposure to Emissions of HAP other than Hydrogen Chloride and 
Chlorine Gas that Have a Common Mechanism of Action. We have identified 
in the table below 40 HAP that are respiratory irritants, including 
hydrogen chloride and chlorine gas. Because these HAP have a common 
mechanism of action, we must determine whether exposure to these HAP 
must be considered when determining that the HI is less than or equal 
to 1.0.
Respiratory Irritant HAP
1,2-Epoxybutane
1,3-dichloropropene
2,4-Toluene diisocyanate
2-Chloroacetophenone
Acetaldehyde
Acrolein
Acrylic acid
Acrylonitrile
Antimony
Beryllium
Bis(2-ethylhexyl)phthalate
Chlorine
Chloroprene
Chromium
Cobalt
Diethanolamine
Epichlorohydrin
Ethylene glycol
Formaldehyde
Hexachlorocyclopentadiene
Hexamethylene 1,6-diisocyanate
Hydrochloric acid
Maleic anhydride
Methyl bromide
Methyl isocyanate
Methyl methacrylate
Methylene diphenyl diisocyanate
N-hexane
Naphthalene
Nickel
Nitrobenzene
Phosgene
Phthalic anhydride
Propylene dichloride
Propylene oxide
Styrene oxide
Titanium tetrachloride
Toluene
Triethylamine
Vinyl acetate

    In making this determination, we would consider only those 
respiratory irritants that are HAP (as opposed to also considering 
respiratory irritants that are criteria pollutants) not only because 
section 112 deals with control of emissions of HAP, but also because 
ambient levels of criteria pollutants that have a common mechanism of 
action with hydrogen chloride and chlorine gas (e.g., SOX, 
NOX, PM, ozone) are controlled through the applicable State 
Implementation Plans demonstrating compliance with the National Ambient 
Air Quality Standards for these pollutants.
    In addition to hydrogen chloride and chlorine gas, several of the 
respiratory irritant HAP listed in the table above may be emitted by 
hazardous waste combustors, including the metals antimony trioxide, 
beryllium, chromium (VI), cobalt, and nickel, and the organic compounds 
Bis(2-ethylhexyl)phthalate, formaldehyde, napthalene, and toluene.\171\ 
We do not believe, however, that these respiratory irritant HAP would 
be emitted by hazardous waste combustors at levels that would result in 
significant Hazard Quotient values. Beryllium and chromium would be 
controlled by emission standards for low volatile metals and the 
remaining metal HAP would be controlled by a particulate matter 
standard. Emissions of the respiratory irritant organic HAP would be 
controlled to trace levels by the MACT standards for carbon monoxide or 
hydrocarbons and destruction and removal efficiency (DRE). Accordingly, 
we propose to require you to quantify and assess emissions from the 
hazardous waste combustor of hydrogen chloride and chlorine gas only; 
you would not be required to account for these other respiratory 
irritant HAP because they would not contribute substantially to the 
Hazard Index.
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    \171\ Betty Willis, et al., Agency for Toxic Substances and 
Disease Registry, U.S. Department of Health and Human Services, 
``Public Health Reviews of Hazardous Waste Thermal Treatment 
Technologies: A Guidance Manual for Public Health Assessors,'' March 
2002, Table 4.
---------------------------------------------------------------------------

    c. Exposure to Emissions of Respiratory Irritant HAP from 
Collocated Sources. You would be required to account for exposure to 
emissions of hydrogen chloride and chlorine gas from all on-site 
hazardous waste combustors subject to subpart EEE, part 63. EPA will 
address exposure to emissions of respiratory irritant HAP from other 
sources that may be collocated with a hazardous waste combustor--for 
example, process vents and fossil fuel boilers--under the residual risk 
requirements of section 112(f) for both hazardous waste combustors and 
(potentially) other MACT source categories. See A Legislative History 
of the Clean Air Act Amendments of 1990 (Senate Print 103-38, 103d 
Cong. 1st sess.) vol. 1 at 868-69 (floor statement of Sen. Durenberger 
(Senate floor manager for section 112) during debate on the Conference 
Report, indicating that EPA is obligated to consider ``combined risks 
of all sources that are collocated with such sources within the same 
major source'' but going on to state that the determination of ample 
margin of safety from emissions from all collocated sources need not 
occur at the same time, but rather can be spread out over the course of 
the residual risk determination process for all major sources.
    d. Exposure to Ambient Background Levels of Respiratory Irritant 
HAP. Background levels of respiratory irritant HAP attributable to 
emissions from off-site sources would not be considered when 
establishing risk-based limits for total chlorine under section 
112(d)(4). Rather, these background levels will be addressed (as may be 
necessary) through other CAA programs such as the urban air toxics 
program.
    e. Acute Exposure Need Not Be Assessed. We have determined that you 
need not assess acute exposure to establish an emission limit for total 
chlorine. You would not be required to model maximum 1-hour average 
off-site ground level concentrations to calculate a Hazard Index (HI) 
based on acute exposure for purposes of establishing an emission limit 
for total chlorine. We conclude that the chronic exposure Hazard Index 
(HI) for the hazardous waste combustor(s) would always exceed the acute 
exposure HI. Thus, the emission limit for total chlorine based on 
chronic exposure would always be more stringent than the limit based on

[[Page 21300]]

acute exposure. As an example, the Cement Kiln Recycling Coalition 
evaluated both chronic and acute exposure to hydrogen chloride and 
chlorine gas for the 14 cement facilities that burn hazardous 
waste.\172\ In all cases, the chronic HI exceeded the acute HI. In 
addition, we determined that the Hazard Quotient (HQ) for chronic 
exposure was always higher than the HQ for acute exposure for the HAP 
we evaluated in the risk assessment we used to support the 1999 Final 
MACT Rule for hazardous waste combustors.\173\
---------------------------------------------------------------------------

    \172\ See Trinity Consultants, ``Analysis of HCl/Cl2 Emissions 
from Cement Kilns for 112(d)(4) Consideration in the HWC MACT 
Replacement Standards,'' September 17, 2003.
    \173\ See USEPA, ``Human Health and Ecological Risk Assessment 
Support to the Development of Technical Standards for Emissions from 
Combustion Units Burning Hazardous Wastes: Background Document,'' 
July 1999.
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    Not requiring an acute exposure analysis reduces the burden on both 
the regulated community and regulatory officials to develop and review 
an analysis that would be superseded by the chronic exposure analysis 
when establishing an emission limit for total chlorine.
    Please note that this discussion relates to evaluating acute 
exposure in establishing an emission limit for total chlorine. Although 
we conclude that the chronic exposure Hazard Index would always be 
higher than the acute exposure Hazard Index, and thus would be the 
basis for the total chlorine emission rate limit, this relates to acute 
versus chronic exposure to a constant, maximum average (e.g., a maximum 
annual average) emission rate of total chlorine from a hazardous waste 
combustor. Acute exposure must be considered, however, when 
establishing operating requirements (e.g., feedrate limit for total 
chlorine and chloride) to ensure that short-term emissions do not 
result in an acute exposure Hazard Index of 1.0 or greater even though 
long-term (e.g., annual average) emissions do not exceed the limit. See 
discussion in Section G.1 below.
3. Does the Proposed Approach Ensure an Ample Margin of Safety?
    Section 112(d)(4) allows EPA to develop risk-based standards for 
HAP ``for which a health threshold has been established'', and the 
resulting standard is to provide an ``ample margin of safety.'' The 
``ample margin of safety'' standard, at least as applied to 
nonthreshold pollutants, typically connotes a two-step process (based 
on the standard first announced in the so-called Vinyl Chloride 
decision (NRDC v. EPA, 824 F. 2d at 1146 (D.C. Cir. 1987)), whereby EPA 
``first [determines] * * * a `safe' or `acceptable' level of risk 
considering only health factors, followed by a second step to set a 
standard that provides an `ample margin of safety', in which costs, 
feasibility, and other relevant factors in addition to health may be 
considered.'' 54 FR at 38045. It is not clear that Congress intended 
this analysis to apply to section 112(d)(4) standards, since the 
principal legislative history to the provision indicates that costs are 
not to be considered in setting standards under section 112(d)(4) (S. 
Rep. 228 at 173), whereas cost normally is a relevant consideration in 
the second part of the ample margin of safety process, as described 
above. Further, if issues of feasibility, cost, and other non-health 
factors are to be taken into account in establishing section 112(d)(4) 
standards, it would be exceedingly difficult, if not practically 
impossible, to do so on a site-specific basis, undermining the approach 
we are proposing here. Nor is it clear that the two-step approach is 
necessarily warranted when considering threshold pollutants, since 
there is greater certainty regarding levels at which adverse health 
effects occur. See Vinyl Chloride, 824 F. 2d at 1165 n. 11.\174\
---------------------------------------------------------------------------

    \174\ Indeed, using the classic two-step approach to ``ample 
margin of safety'' could result in the same standards we are 
proposing as MACT for HCl and Cl2 for all of the affected source 
categories (if one assumes that all of the standards would be below 
protective risk-based levels for all sources), since we believe that 
the proposed technology-based standards would be justifiable based 
on considerations of technical feasibility and cost, and so would 
provide a reasonable margin of safety beyond the risk-based level 
considered protective.
---------------------------------------------------------------------------

    We specifically request comment on how to ensure that the emission 
limits calculated using the health threshold values (e.g., RfCs and 
AEGL-1 values), and after considering emissions of respiratory irritant 
HAP from collocated hazardous waste combustors, achieve an ample margin 
of safety.
4. How Are Effects on Terrestrial Animals Addressed?
    We believe the RfC values for hydrogen chloride and chlorine gas 
should be generally protective for chronic effects in most, if not all, 
fauna. We note that the RfC values are based on animal studies. 
Although the AEGL-1 values for acute exposure are based on human data, 
we nonetheless expect that they too would be generally protective of 
most fauna, absent information to the contrary.
5. How Are Effects on Plants Addressed?
    EPA has not established ecotoxicity values that are protective of 
vegetation. Nonetheless, for the reasons discussed below we do not 
believe that ambient concentrations of hydrogen chloride and chlorine 
gas that meet the human health threshold values discussed above will 
pose adverse effects on plants.
    As discussed in the preamble to the Lime Manufacturing NESHAP 
proposed rule (67 FR 78056),\175\ chronic exposure to about 600 [mu]g/
m3 can be expected to result in discernible effects, 
depending on the plant species. Effects of acute, 20-minute exposures 
of 6,500 to 27,000 [mu]g/m3 include leaf injury and decrease 
in chlorophyll levels in various species. The hydrogen chloride RfC of 
20 [mu]g/m3 is well below the 600 [mu]g/m3 effect 
level, and the AEGL-1 value for hydrogen chloride of 2,700 [mu]g/
m3 is far below the 6500 [mu]g/m3 acute effect 
level. Therefore, no adverse exposure effects are anticipated.
---------------------------------------------------------------------------

    \175\ EPA published the final rule at 69 FR 394, January 5, 
2004.
---------------------------------------------------------------------------

    We specifically request additional information on ecotoxicity for 
both acute and chronic exposure of vegetation to hydrogen chloride and 
chlorine gas.

C. How Would You Determine if Your Total Chlorine Emission Rate Meets 
the Eligibility Requirements Defined by the National Exposure 
Standards?

    Under the risk-based approach to establish an alternative to the 
MACT standard for your total chlorine emission limit, you would have to 
demonstrate that emissions of total chlorine from on-site hazardous 
waste combustors result in exposure to the actual most-exposed 
individual residing off site of a Hazard Index of less than or equal to 
1.0. (Put another way, we are proposing to establish this level of risk 
as the national emission limitation, with the rule further establishing 
the mechanisms by which this demonstration can be made, such 
demonstrations yielding a site-specific limit for total chlorine.) 
\176\ The rule would also establish two ways by which you could make 
this demonstration: by a look-up table analysis or by a site-specific 
compliance demonstration (as explained below). The look-up table is 
much simpler to use, but establishes emission rates that are quite 
conservative because there are few site-specific parameters considered 
and

[[Page 21301]]

therefore the model's default assumptions are conservative. If you 
elect not to comply with those conservative emission rates, you may 
perform a site-specific compliance demonstration.
---------------------------------------------------------------------------

    \176\ Rather than establishing emission rate limits for hydrogen 
chloride and chlorine gas, or for total chlorine, for each 
combustor, you would actually establish an HCl-equivalent emission 
rate limit for each combustor, as discussed below in the text.
---------------------------------------------------------------------------

    The look-up table identifies the total chlorine emission limit in 
terms of a toxicity-weighted HCl-equivalent emission rate. Under the 
site-specific compliance demonstration alternative, the total chlorine 
limit would also be expressed as a toxicity weighted HCl-equivalent 
emission rate even though you would model emissions of hydrogen 
chloride and chlorine gas from each on-site hazardous waste combustor. 
We define the toxicity-weighted HCl-equivalent emission rate below.
1. Toxicity-Weighted HCl-Equivalent Emission Rates
    Although the MACT emission standards for total chlorine are 
expressed as a stack gas emission concentration--ppmv--we must use an 
emission rate (e.g., lb/hr) format for risk-based standards. This is 
because health and environmental risk is related to the mass rate of 
emissions over time.
    In addition, we propose to use a toxicity-weighted HCl-equivalent 
emission rate (HCl-equivalents) as the metric for the combined 
emissions of hydrogen chloride and chlorine gas. The HCl-equivalent 
emission rate considers the RfCs of hydrogen chloride and chlorine gas 
when calculating the combined emission rate according to this equation:
    ERdtw = [Sigma](ERi x (RfCHC1/
RfCi))

where:

    ERtw is the HC1-equivalent emission rate, lb/hr
    ERi is the emission rate of HAP i in lbs/hr
    RfCi is the reference concentration of HAP i
    RfCHC1 is the reference concentration of HCl
    Expressing the risk-based emission limit as HCl-equivalents enables 
you to use the equation to apportion the emission rate limit between 
hydrogen chloride and chlorine gas as you choose. Thus, you need to be 
concerned with ensuring compliance with the HCl-equivalent emission 
rate only, rather than with emission rates for hydrogen chloride and 
chlorine gas individually.
    Under the look-up table analysis discussed below, you would use the 
hydrogen chloride and chlorine gas emission rates you choose for each 
on-site hazardous waste combustor to calculate the HCl-equivalent 
emission rate for the combustor. You would sum the HCl-equivalent 
emission rates for your hazardous waste combustors. If you elect to use 
the site-specific compliance demonstration to document eligibility, you 
would model emission rates of hydrogen chloride and chlorine gas that 
you choose for each on-site hazardous waste combustor to document that 
the facility Hazard Index is less than or equal to 1.0. You would then 
use the hydrogen chloride and chlorine gas emission rates you model to 
establish an HCl-equivalent emission rate limit for each combustor.
2. How Would You Conduct a Look-Up Table Analysis?
    You would sum the HCl-equivalent rates for all combustors, and 
compare the sum to the appropriate allowable emission rate in Table 1 
of proposed Sec.  63.1215. Emission rates are provided as a function of 
stack height and distance to the nearest property boundary. If you have 
more than one hazardous waste combustor at your facility, you would use 
the average value for stack height (i.e., the averaged stack heights of 
the different hazardous waste combustors at your facility), and the 
minimum distance between any hazardous waste combustor stack and the 
property boundary.\177\
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    \177\ HCl production furnaces are not eligible for the risk-
based total chlorine emission limits because we are proposing that 
the MACT standard for total chlorine would be used as a surrogate to 
control metal HAP. Nonetheless, if you operate an HCl production 
furnace at a facility where you would establish risk-based emission 
limits for total chlorine for other hazardous waste combustors, you 
would account for total chlorine emissions from the HCl production 
furnace in your risk-based eligibility demonstration for the other 
combustors. If, for example, you use the look-up table to 
demonstrate eligibility, you would include the stack height of the 
HCl production furnace in the calculation of average stack height 
for your combustors, and you would consider whether the HCl 
production furnace stack is the closest hazardous waste combustor 
stack to the property boundary.
---------------------------------------------------------------------------

    If one or both of these values for stack height and distance to 
nearest property boundary do not match the exact values in the look-up 
table, you would use the next lowest table value. This would ensure 
that the HCl-equivalent emission rate limits are protective.
    You would not be eligible for the look-up table analysis if your 
facility is located in complex terrain because the plume dispersion 
models used to calculate the emission rates are not applicable to 
sources in complex terrain.
    You would be eligible to comply with the risk-based alternative 
HCl-equivalent emission rate limits you calculate for each combustor if 
the facility HCl-equivalent emission rate limit (i.e., the sum of the 
HCl-equivalent emission rates for all hazardous waste combustors) does 
not exceed the appropriate value specified in the look-up table. Please 
note, however, that we also propose to cap the HCl-equivalent emission 
rate limits for incinerators, cement kilns, and lightweight aggregate 
kilns at a level that ensures that the current total chlorine emission 
standards are not exceeded. See discussion below in Section D.
    Please note that the emission rates provided in Table 1 are 
different from those provided for industrial boilers in the Industrial 
Boiler and Process Heater MACT rule recently promulgated. This is 
because the key parameters used by the SCREEN3 atmospheric dispersion 
model to predict the normalized air concentrations that EPA used to 
establish HCl-equivalent emission rates as a function of stack height 
and distance to property boundary for industrial boilers--stack 
diameter, stack exit gas velocity, and stack exit gas temperature--are 
substantially different for hazardous waste burning incinerators, 
cement kilns, and lightweight aggregate kilns. Thus, the maximum HCl-
equivalent emission rates for hazardous waste combustors would 
generally be lower than those EPA established for industrial boilers.
    To ensure that the HCl-equivalent emission rate limits in a look-up 
table analysis for hazardous waste combustors would not result in a 
Hazard Index of more than 1.0, we propose to establish limits based on 
the maximum annual average normalized air concentrations in U.S. EPA, 
``A Tiered Modeling Approach for Assessing the Risk Due to Sources of 
Hazardous Air Pollutants,'' March 1992, Table 1. Those normalized air 
concentrations are based on conservative simulations of toxic pollutant 
sources with Gaussian plume dispersion models. The simulations are 
conservative regarding factors such as meteorology, building downwash, 
plume rise, etc.
    We specifically request comment on whether the HCl-equivalent 
emission rates in Table 1 are too conservative and thus have limited 
utility because they apply to all hazardous waste combustors 
generically. Alternatively, we could establish less conservative 
emission rates in look-up tables specific to various classes of 
hazardous waste combustors (e.g., cement kilns, incinerators) that have 
similar stack properties that affect predicted emissions. We request 
comment on whether industry stakeholders would be likely to use the 
proposed look-up table eligibility demonstration or revised

[[Page 21302]]

look-up tables tailored to specific classes of hazardous waste 
combustors, in lieu of the site-specific compliance eligibility 
demonstration.
3. How Would You Conduct a Site-Specific Compliance Demonstration?
    If you fail to demonstrate that your facility is able to comply 
with the alternative risk-based emission limit using the look-up table 
approach, you may choose to perform a site-specific compliance 
demonstration. We are proposing that you may use any scientifically-
accepted peer-reviewed risk assessment methodology for your site-
specific compliance demonstration. An example of one approach for 
performing the demonstration for air toxics can be found in the EPA's 
``Air Toxics Risk Assessment Reference Library, Volume 2, Site-Specific 
Risk Assessment Technical Resource Document,'', which may be obtained 
through the EPA's Air Toxics Web site at http://www.epa.gov/ttn/atw.
    Your facility would be eligible for the alternative risk-based 
total chlorine emission limit if your site-specific compliance 
demonstration shows that the maximum Hazard Index for hydrogen chloride 
and chlorine gas emissions from all on-site hazardous waste combustors 
at a location where people live (i.e., the maximum actual most exposed 
individual) is less than or equal to 1.0, rounded to the nearest tenths 
decimal place (0.1).\178\ You would estimate long-term inhalation 
exposures for this individual most exposed to the facility's emissions 
through the estimation of annual or multi-year average ambient 
concentrations. You would use site-specific, quality-assured data 
wherever possible, and health-protective default assumptions wherever 
site-specific data are not available. You would document the data and 
methods used for the assessment so that it is transparent and can be 
reproduced by an experienced risk assessor and emissions measurement 
expert.
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    \178\ When calculating Hazard Index values, the final HI value 
should be rounded to one decimal place given the uncertainties in 
the analyses. For example, an HI calculated to be 0.94 would be 
presented as 0.9, while an HI calculated to be 0.96 would be 
presented as 1.0 (which would pass the eligibility demonstration). 
Intermediate calculations should use as many significant figures as 
appropriate.
---------------------------------------------------------------------------

    Your site-specific compliance demonstration need not assume any 
attenuation of exposure concentrations due to the penetration of 
outdoor pollutants into indoor exposure areas. In addition, we are 
proposing that the demonstration need not assume any reaction or 
deposition of hydrogen chloride and chlorine gas from the emission 
point to the point of exposure. In particular, you would assume that 
chlorine gas is not photolyzed to hydrogen chloride, as discussed in 
Section B.1 above.
    If your site-specific compliance demonstration documents that the 
maximum Hazard Index from your hazardous waste combustors is less than 
or equal to 1.0, you would establish a maximum HCl-equivalent emission 
rate limit for each combustor using the hydrogen chloride and chlorine 
gas emission rates you modeled in the site-specific compliance 
demonstration. Please note, however, that we also propose to cap the 
HCl-equivalent emission rate limits for incinerators, cement kilns, and 
lightweight aggregate kilns at a level that ensures that the current 
total chlorine emission standards are not exceeded. See discussion 
below in Section D.

D. What Is the Rationale for Caps on the Risk-Based Emission Limits?

    The HCl-equivalent emission rate limits would be capped for 
incinerators, cement kilns, and lightweight aggregate kilns at a level 
that ensures total chlorine emissions do not exceed the interim 
standards provided by Sec. Sec.  63.1203, 63.1204, and 63.1205. These 
caps on the risk-based emission limits would ensure that emission 
levels do not increase above the emission levels that sources are 
currently required to achieve, thus precluding ``back-sliding.'' Given 
the discretionary nature of section 112(d)(4), and the general purpose 
of the section 112(d) standard-setting process to lock-in performance 
of current emission control technology, we think it appropriate to 
invoke the provision in a manner that does not result in emission 
increases over current regulatory levels.
    We considered whether to propose emission caps for boilers at the 
levels allowed by the RCRA emission standards under Sec.  266.107 but 
conclude that this would be inappropriate. This is because the RCRA 
emission standards are also risk-based standards but are based on risk 
criteria that we considered appropriate in 1987 when we proposed those 
rules. The risk criteria we propose today are substantially different 
from those used to implement Sec.  266.107. For example, the RfC for 
hydrogen chloride is higher now while the RfC for chlorine gas is 
lower. In addition, we considered a Hazard Index of 0.25 acceptable 
under the RCRA rule, while we propose today a Hazard Index limit of 
less than or equal to 1.0. Because the risk criteria for the current 
RCRA rules are substantially different from the risk criteria we 
propose today for invoking Section 112(d)(4), we do not believe it is 
appropriate to use the RCRA standards as a cap for establishing risk-
based standards under Section 112(d)(4).
    Capping risk-based emission limits for incinerators, cement kilns, 
and lightweight aggregate kilns at an HCl-equivalent emission rate 
corresponding to the MACT interim standards would not increase 
compliance costs (by definition). Thus, the cap would help ensure that 
emissions are protective of public health with an ample margin of 
safety, and that there are no significant adverse environmental 
impacts.
    To implement the cap, you would ensure that the hydrogen chloride 
and chlorine gas emission rates you use to calculate the HCl-equivalent 
emission rate for incinerators, cement kilns, and lightweight aggregate 
kilns would not result in total chlorine emission concentrations 
exceeding the standards provided by Sec. Sec.  63.1203, 63.1204, and 
63.1205.

E. What Would Your Risk-Based Eligibility Demonstration Contain?

    To enable regulatory officials to review and approve the results of 
your risk-based demonstration, you would include the following 
information, at a minimum: (1) Identification of each hazardous waste 
combustor combustion gas emission point (e.g., generally, the flue gas 
stack); (2) the maximum capacity at which each combustor will operate, 
and the maximum rated capacity for each combustor, using the metric of 
stack gas volume emitted per unit of time, as well as any other metric 
that is appropriate for the combustor (e.g., million Btu/hr heat input 
for boilers; tons of dry raw material feed/hour for cement kilns); (3) 
stack parameters for each combustor, including, but not limited to 
stack height, stack area, stack gas temperature, and stack gas exit 
velocity; (4) plot plan showing all stack emission points, nearby 
residences, and property boundary line; (5) identification of any stack 
gas control devices used to reduce emissions from each combustor; (6) 
identification of the RfC values used to calculate the HCl-equivalent 
emissions rate; (7) calculations used to determine the HCl-equivalent 
emission rate as prescribed above; (8) for incinerators, cement kilns, 
and lightweight aggregate kilns, calculations used to determine that 
the HCl-equivalent emission rate limit for each combustor does not 
exceed the standards for total chlorine at Sec. Sec.  63.1203, 63.1204, 
and 63.1205; and (9) the HCl-equivalent emission rate limit for each 
hazardous waste

[[Page 21303]]

combustor that you will certify in the Documentation of Compliance 
required under Sec.  63.1211(d) that you will not exceed, and the 
limits on the operating parameters specified under Sec.  63.1209(o) 
that you will establish in the Documentation of Compliance.
    If you use the look-up table analysis to demonstrate that your 
facility is eligible for the risk-based alternative for the total 
chlorine emission limit, your eligibility demonstration would also 
contain, at a minimum, the following: (1) Calculations used to 
determine the average stack height of on-site hazardous waste 
combustors; (2) identification of the combustor stack with the minimum 
distance to the property boundary of the facility; (3) comparison of 
the values in the look-up table to your maximum HCl-equivalent emission 
rate.
    If you use a site-specific compliance demonstration to demonstrate 
that your facility is eligible for the risk-based alternative for the 
total chlorine emission limit, your eligibility demonstration would 
also contain, at a minimum, the following: (1) Identification of the 
risk assessment methodology used; (2) documentation of the fate and 
transport model used; and (3) documentation of the fate and transport 
model inputs, including the stack parameters listed above converted to 
the dimensions required for the model. In addition, you would include 
all of the following that apply: (1) Meteorological data; (2) building, 
land use, and terrain data; (3) receptor locations and population data; 
and (4) other facility-specific parameters input into the model. Your 
demonstration would also include: (1) Documentation of the fate and 
transport model outputs; (2) documentation of any exposure assessment 
and risk characterization calculations; and (3) documentation of the 
predicted Hazard Index for HCl-equivalents and comparison to the limit 
of less than or equal to 1.0.

F. When Would You Complete and Submit Your Eligibility Demonstration?

    You would be required to submit your eligibility demonstration to 
the permitting authority for review and approval.\179\ In addition you 
would submit an electronic copy of the demonstration to [email protected] 
(preferably) or a hard copy to: U.S. EPA, Risk and Exposure Assessment 
Group, Emission Standards Division (C404-01), Attn: Group Leader, 
Research Triangle Park, North Carolina 27711.
---------------------------------------------------------------------------

    \179\ Since the Title V permitting authority is delegated to 
States in virtually all instances, the permit limit would thus be 
issued as a matter of State authority (generally in parallel with a 
delegation of section 112 authority pursuant to CAA section 112(l)), 
and be reviewable only in State courts.
---------------------------------------------------------------------------

    Requiring prior approval of these eligibility demonstrations is 
warranted because hazardous waste combustor may feed chlorine at high 
feedrates which may result in emissions of hydrogen chloride and 
chlorine gas that approach or exceed the RfCs (i.e., absent compliance 
with either the MACT standards or the section 112(d)(4) risk-based 
standards). Thus, prior approval of alternative HCl-equivalent emission 
rate limits is warranted to ensure that emissions are protective with 
an ample margin of safety.
1. Existing Sources
    If you operate an existing source, you must be in compliance with 
the emission standards on the compliance date. Consequently, if you 
elect to comply with the alternative risk-based emission rate limit for 
total chlorine, you must have completed the eligibility demonstration 
and received approval from your delegated permitting authority by the 
compliance date.
    You would submit documentation supporting your eligibility 
demonstration not later than 12 months prior to the compliance date.
    Your permitting officials will notify you of approval or intent to 
disapprove your eligibility demonstration within 6 months after receipt 
of the original demonstration, and within 3 months after receipt of any 
supplemental information that you submit. A notice of intent to 
disapprove your eligibility demonstration will identify incomplete or 
inaccurate information or noncompliance with prescribed procedures and 
specify how much time you will have to submit additional information. 
If your permitting authority has not approved your eligibility 
demonstration to comply with a risk-based HCl-equivalent emission 
rate(s) by the compliance date, you must comply with the MACT emission 
standards for total chlorine gas under Sec. Sec.  63.1216, 63.1217, 
63.1219, 63.1220, and 63.1221.\180\
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    \180\ Please note that, if your eligibility demonstration is not 
approved prior to the compliance date, a request to extend the 
compliance date to enable you to undertake measures to comply with 
the MACT standards for total chlorine will not be approved unless 
you made a good faith effort to submit a complete, accurate, and 
timely eligibility demonstration and to respond to concerns raised 
by the permitting authority or U.S. EPA.
---------------------------------------------------------------------------

2. New Sources
    If you operate a source that is not an existing source and that 
becomes subject to Subpart EEE, you must comply with the MACT emission 
standards for total chlorine unless and until your eligibility 
demonstration has been approved by the permitting authority.
    If you operate a new or reconstructed source that starts up before 
the effective date of the emission standards proposed today, or a solid 
fuel-fired boiler or liquid fuel-fired boiler that is an area source 
that increases its emissions or its potential to emit such that it 
becomes a major source of HAP before the effective date of the emission 
standards proposed today (and thus becomes subject to emission 
standards applicable to major sources, including the standard for total 
chlorine), you would be required to comply with the emission standards 
under Sec. Sec.  63.1216 and 63.1217 until your eligibility 
demonstration is completed, submitted, and approved by your permitting 
authority.
    If you operate a new or reconstructed source that starts up after 
the effective date of the emission standards proposed today, or a solid 
fuel-fired boiler or liquid fuel-fired boiler that is an area source 
that increases its emissions or its potential to emit such that it 
becomes a major source of HAP after the effective date of the emission 
standards proposed today (and thus becomes subject to emission 
standards applicable to major sources including the standard for total 
chlorine), you would be required to comply with the emission standards 
under Sec. Sec.  63.1216 and 63.1217 until your eligibility 
demonstration is completed, submitted, and approved by your permitting 
authority.

G. How Would the Risk-Based HCl-Equivalent Emission Rate Limit Be 
Implemented?

    Upon approval by the permitting authority of your eligibility 
demonstration, the HCl-equivalent emission rate limit established in 
the demonstration for your hazardous waste combustor(s) becomes the 
applicable emission limit for total chlorine in lieu of the MACT 
standard for total chlorine.
1. What Are the Testing and Monitoring Requirements?
    To ensure compliance with the alternative HCl-equivalent emission 
rate limit for your combustor(s), you would conduct performance testing 
as required for the MACT standards and establish limits on the same 
operating parameters that apply to sources complying with the MACT 
standards for total chlorine under Sec.  63.1209(o). You would 
establish and comply with these operating parameter limits just as you 
would establish and comply with the limits for the MACT emission 
standard for total chlorine, with the exception of the

[[Page 21304]]

chlorine feedrate limit, as discussed below. For example, existing 
sources would establish these limits in the Documentation of Compliance 
required under Sec.  63.1211(c) and begin complying with them not later 
than the compliance date. Existing sources would also revise the 
operating limits as necessary based on the initial comprehensive 
performance test and begin complying with the revised operating limits 
not later than when the Notification of Compliance is postmarked, as 
required under Sec. Sec.  63.1207(j) and 63.1210(b).
    The limit on chlorine feedrate required under Sec.  63.1209(o)(1) 
would be established differently to ensure compliance with the HCl-
equivalent emission rate limit rather than the total chlorine emission 
standard. To ensure that facility-wide hazardous waste combustor 
emissions of HCl-equivalents result in exposures equivalent to a Hazard 
Index of less than or equal to 1.0, the feedrate limit for chlorine 
would be established as the average of the test run averages and the 
averaging period for compliance would be one year. A yearly rolling 
average is appropriate for risk-based emission limits rather than the 
12-hour rolling average applicable to the MACT standards because the 
risk-based emission limit is based on chronic exposure.
    As discussed in Section B.2.e above, although we conclude that the 
chronic exposure Hazard Index would always be higher and thus be the 
basis for the total chlorine emission rate limit, we still must be 
concerned about acute exposure attributable to short-term emission 
rates higher than the maximum average emission rate limit. For example, 
the annual average limit on chlorine (i.e., total chlorine and 
chloride) feedrate would allow a source to feed very high levels of 
chlorine for short periods of time, potentially resulting in 
exceedances of the acute exposure Hazard Index based the AEGL-1 values 
for hydrogen chloride and chlorine gas. We specifically request comment 
on how a short-term limit on chlorine feedrate could be established for 
each hazardous waste combustor to ensure that the acute exposure Hazard 
Index is less than or equal to 1.0. One approach would be for you to 
extrapolate from the chlorine feedrate during the comprehensive 
performance test to the feedrate projected to achieve emission rates of 
hydrogen chloride and chlorine gas that result in an acute exposure 
Hazard Index of 1.0.\181\ This feedrate would be a 1-hour average 
feedrate limit. This approach uses the reasonable assumption that there 
is a proportional relationship between chlorine feedrate and the 
emission rate of hydrogen chloride and chlorine gas. To extrapolate 
feedrates, you would consider the system removal efficiency achieved 
during the performance test for sources equipped with wet or dry acid 
gas scrubbers and for cement kilns.\182\ Other sources would assume a 
zero system removal efficiency because any removal efficiency that may 
be measured would be incidental and not reproducible.
---------------------------------------------------------------------------

    \181\ We also request comment on whether extrapolation of the 
chlorine feedrate should be allowed to 100% of the Hazard Index 
limit of 1.0, or whether a more conservative approach of limited 
extrapolation to a fraction of the Hazard Index (e.g., 0.8) would be 
warranted, given the uncertainties inherent in projecting emissions 
from extrapolated feedrates.
    \182\ We request comment on whether the system removal 
efficiency a cement kiln demonstrates during a performance test 
because of the alkalinity of the raw material is reasonably 
indicative of the system removal efficiency it routinely achieves 
(i.e., is the system removal efficiency reasonably reproducible).
---------------------------------------------------------------------------

    The approach discussed above would be applicable if you use the 
site-specific compliance eligibility demonstration. If you use the 
look-up table for your eligibility demonstration, an alternative 
approach would be needed to establish a short-term chlorine feedrate 
limit. One approach would be to establish a look-up table for maximum 
1-hour average HCl-equivalents based on acute exposure. Acute exposure 
HCl-equivalents would be calculated using the AEGL-1 values for 
hydrogen chloride and chlorine gas, and the look-up table of acute 
exposure maximum emission rate limits would be based on normalized air 
concentrations for maximum 1-hour average ground level 
concentrations.\183\ You would extrapolate the chlorine feedrate from 
the level achieved during the comprehensive performance test to a level 
that would not exceed the acute exposure HCl-equivalent emission rate 
limit for each combustor provided in the look-up table. This feedrate 
would be a 1-hour average feedrate limit.
---------------------------------------------------------------------------

    \183\ We would use the normalized maximum 1-hour average 
concentrations in U.S. EPA, ``A Tiered Modeling Approach for 
Assessing the Risk Due to Sources of Hazardous Air Pollutants,'' 
March 1992, Table 2.
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    We specifically request comment on these approaches to establish a 
short-term limit on the feedrate of total chlorine and chloride to 
ensure that the acute exposure Hazard Index for hydrogen chloride and 
chlorine gas is less than or equal to 1.0.
2. What Test Methods Would You Use?
    Although you would comply with the MACT standard for total chlorine 
using stack Method 26/26A, certain sources would not be allowed to use 
that method to demonstrate compliance with the risk-based HCl-
equivalent emission rate limit.\184\ Cement kilns and sources equipped 
with a dry acid gas scrubber should use EPA Method 320/321 or ASTM D 
6735-01 to measure hydrogen chloride, and the back-half (caustic 
impingers) of Method 26/26A to measure chlorine gas. Incinerators, 
boilers, and lightweight aggregate kilns should use EPA Method 320/321 
or ASTM D 6735-01 to measure hydrogen chloride, and Method 26/26A to 
measure total chlorine, and calculate chlorine gas by difference if: 
(1) the bromine/chlorine ratio in feedstreams is greater than 5 
percent; or (2) the sulfur/chlorine ratio in feedstreams is greater 
than 50 percent.
---------------------------------------------------------------------------

    \184\ Even though Method 26/26A may bias total chlorine emission 
measurements low for cement kilns for reasons discussed in the text, 
it is appropriate to allow compliance with the technology-based MACT 
emission standards for total chlorine using that method. Because the 
MACT standards are developed using data obtained using Method 26/
26A, allowing that method for compliance will achieve reductions in 
total chlorine emissions. For the same reason, it would be 
inappropriate to require compliance with unbiased methods because 
the average of the best performing sources might not be able to 
achieve the standard.
---------------------------------------------------------------------------

    a. Method 26/26A Has a Low Bias for Hydrogen Chloride in Certain 
Situations. Method 26/26A has a low bias for hydrogen chloride for 
sources that emit particulate matter than can adsorb hydrogen chloride: 
cement kilns and sources equipped with a dry acid gas scrubber. 
Particulate matter caught by the Method 26/26A filter scrubs hydrogen 
chloride from the sample gas, and can result in measurements that are 
biased low by 2 to 30 times.\185\ Chlorine gas is not adsorbed so that 
chlorine gas emissions are not biased by this mechanism.
---------------------------------------------------------------------------

    \185\ USEPA, ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume III: Selection of MACT Standards and 
Technologies,'' March 2004.
---------------------------------------------------------------------------

    b. Method 26/26A Can Have a Low Bias for Chlorine Gas and a High 
Bias for Hydrogen Chloride, but Has No Bias for Total Chlorine. Method 
26/26A also has a low bias for chlorine and a high bias for hydrogen 
chloride when bromine is present at significant levels. Bromine has a 
strong effect on the bias. Although the various interhalogen reactions 
are extremely complex and may depend on a variety of system parameters, 
it appears that each bromine molecule can react with a chlorine 
molecule in the acidic impingers of Method 26/26A where hydrogen 
chloride is captured, converting the chlorine to chloride ions which 
are

[[Page 21305]]

reported as hydrogen chloride. Total chlorine measurements (i.e., 
hydrogen chloride and chlorine gas, combined, reported as Cl-
equivalents), however, are not affected. To minimize this bias, we 
propose to require sources that have a bromine/chlorine feedrate 
exceeding 5 percent to use alternative methods discussed below. Given 
the strong bias that bromine can have on M26/26A measurements, we 
believe a 5 percent limit on the ratio is within the range of 
reasonable values that we could select. We specifically request comment 
on this or other approaches to minimize the bromine bias.
    Method 26/26A also has a low bias for chlorine and a high bias for 
hydrogen chloride when sulfur is present at substantial levels relative 
to the levels of chlorine. The capture of chlorine in the acidic 
impingers that collect hydrogen chloride has been shown to rapidly 
increase when the ratio of SO2/HCl (both expressed in ppmv) exceeds 
0.5. Again, total chlorine measurements are not biased. To minimize 
this bias, we believe that a 50 percent limit on the ratio of the 
sulfur/chlorine feedrate is within the range of reasonable values that 
we could select. We specifically request comment on this or other 
approaches to minimize the sulfur dioxide bias.
    c. Unbiased Methods Are Available. The Agency recently developed 
three methods for hydrogen chloride in the context of the Portland 
Cement MACT rule for purposes of area source determinations: Methods 
320, 321, and 322. Although M322 (GFCIR, Gas Filter Correlation Infra-
Red) is easier to use and less expensive than M320/M321 (FTIR, Fourier 
Transform Infra-Red), the Agency did not promulgated M322 in the final 
Portland Cement MACT rule because of accuracy concerns resulting from 
emissions sampling of lime manufacturing kilns in the context of 
developing the Lime Manufacturing MACT rule.
    The Agency has also adopted an American Society of Testing and 
Materials (ASTM) standard for measuring hydrogen chloride emissions: 
ASTM D 6735-01. This method (and M321) is allowed for area source 
determinations under the Lime Manufacturing MACT rule. 69 FR 394 (Jan. 
5, 2004). The method is an impinger method, like M26/26A, but with 
several improvements. For example, the method uses a rejection probe 
(i.e., the probe is directed counter to the gas flow), the filter is 
heated to minimize adsorption of hydrogen chloride on particulate 
matter that may catch on the filter, glassware must be conditioned, and 
improved quality assurance/quality control procedures are prescribed.

H. How Would You Ensure That Your Facility Remains Eligible for the 
Risk-Based Emission Limit?

1. Changes Over Which You Have Control
    Changes in design, operation, or maintenance of a hazardous waste 
combustor that may affect the rate of emissions of HCl-equivalents from 
the combustor are subject to the requirements of Sec.  63.1206(b)(5).
    If you change the information documented in the demonstration of 
eligibility for the HCl-equivalent emission rate limit which is used to 
establish the HCl-equivalent emission rate limit, you would be subject 
to the following procedures.
    a. Changes that Would Decrease the Allowable HCl-Equivalent 
Emission Rate Limit. If you plan to make a change that would decrease 
the allowable HCl-equivalent emission rate limit documented in your 
eligibility demonstration, you would comply with Sec.  
63.1206(b)(5)(i)(A-C) regarding notifying the permitting authority of 
the change, submitting a comprehensive performance test schedule and 
test plan, comprehensive performance testing, and restriction on 
burning hazardous waste prior to submitting a revised Notification of 
Compliance. An example of a change that would decrease the allowable 
HCl-equivalent emission rate limit is location of the property boundary 
closer to the nearest hazardous waste combustor stack when using the 
look-up table to make the eligibility demonstration.
    b. Changes that Would Not Decrease the Allowable HCl-Equivalent 
Emission Rate Limit. If you determine that a change would not decrease 
the allowable HCl-equivalent emission rate limit documented in your 
eligibility demonstration, you would document the change in the 
operating record upon making such change. If the change would increase 
your allowable HCl-equivalent emission rate limit and you elect to 
establish a higher HCl-equivalent limit, you must submit a revised 
eligibility demonstration for review and approval. Upon approval of the 
revised eligibility demonstration, you must comply with Sec.  
63.1206(b)(5)(i)(A)(2), (B), and (C) regarding submitting a 
comprehensive performance test schedule and test plan, comprehensive 
performance testing, and restriction on burning hazardous waste prior 
to submitting a revised Notification of Compliance.
2. Changes Over Which You Do Not Have Control
    Over time, factors and information over which you do not have 
control and which you use to make your eligibility demonstration may 
change. For example, if you use a site-specific compliance 
demonstration, individuals may locate within the area impacted by 
emissions such that the most exposed individual may be exposed to 
higher ground level concentrations than previously estimated. This 
could lower your allowable HCl-equivalent emission rate limit. 
Consequently, you would be required to review the documentation you use 
in your eligibility demonstration every five years on the anniversary 
of the comprehensive performance test and submit for review with the 
test plan either a certification that the information used in your 
eligibility demonstration has not changed in a manner that would 
decrease the allowable HCl-equivalent emission rate limit, or a revised 
eligibility demonstration for a revised HCl-equivalent emission rate 
limit.
    If you determine that you cannot demonstrate compliance with a 
lower allowable HCl-equivalent emission rate limit during the 
(subsequent) comprehensive performance test because you cannot complete 
changes to the design or operation of the source prior to the test, you 
may request that the permitting authority grant you additional time as 
necessary to make those changes, not to exceed three years.

I. Request for Comment on an Alternative Approach: Risk-Based National 
Emission Standards

    As noted earlier, another approach to implement section 112(d)(4)--
and one EPA has used in past MACT rules--would be to establish national 
emission standards for each source category to ensure that the 
emissions from each source within the category are protective of public 
health with an ample margin of safety (and do not pose adverse 
environmental impacts). Under this approach, dispersion modeling of 
representative worst-case sources (or all sources) within a category 
would be used to identify an emission level that meets the section 
112(d)(4) criteria for all sources within the category. Thus, the same 
risk-based national emission standard would be established for each 
source in each source category under this approach, rather than the 
approach we discuss above of establishing a national exposure standard 
based on a uniform level of protection that you would use to establish 
a site-specific emission limit.

[[Page 21306]]

    The approach of establishing a risk-based national emission 
standard for a source category has the advantage of being less 
burdensome to implement both for the regulated community and regulatory 
authorities. It has the disadvantage, however, of requiring 
documentation ``up front'' to support the proposed emission standards. 
EPA does not have the time, data, or resources to conduct the analyses 
required to support this approach.
    The Cement Kiln Recycling Coalition (CKRC), however, has submitted 
documentation supporting a national risk-based emission standard for 
total chlorine for cement kilns.\186\ CKRC uses normalized air 
concentrations from ISC-PRIME and ISCST3 to estimate maximum annual 
average and maximum 1-hour average off-site ground level concentrations 
of hydrogen chloride and chlorine gas for each source. CKRC assumes 
that each kiln emits total chlorine at 130 ppmv, the current Interim 
Standard, and that emissions of hydrogen chloride and chlorine gas 
partition at the same ratio as measured during the most recent 
compliance test. The analysis indicates that the facility Hazard Index 
for 1-hour exposures was below 0.2 for the kilns at all facilities, and 
the facility Hazard Index for long-term exposures was below 0.2 for the 
kilns at 8 of 14 facilities. Emissions from kilns at the remaining 6 
facilities can potentially result in facility Hazard Index values up to 
0.7.
---------------------------------------------------------------------------

    \186\ Trinity Consultants, ``Analysis of HCl/Cl2 Emissions from 
Cement Kilns for 112(d)(4) Consideration in the HWC MACT Replacement 
Standards,'' September 17, 2003.
---------------------------------------------------------------------------

    Notwithstanding that CKRC followed the guidance we suggested to 
identify a section 112(d)(4) risk-based emission standard for a source 
category, we conclude that establishing a stack gas concentration-based 
total chlorine standard of 130 ppmv may not be protective with an ample 
margin of safety. Even though the highest Hazard Index for any facility 
in the category is below the maximum HI of less than 1.0, the Hazard 
Index value for a facility could increase even though sources do not 
exceed an emission standard of 130 ppmv. This is because the Hazard 
Index is affected by the mass emission rate (e.g., lb/hr) of hydrogen 
chloride and chlorine gas individually. Thus the Hazard Index could 
increase from the values CKRC has calculated even though each source 
complies with a 130 ppmv total chlorine emission standard given that: 
(1) The RfC for chlorine gas is 100 times lower than the RfC for 
hydrogen chloride; (2) the partitioning of total chlorine between 
hydrogen chloride and chlorine gas could change so that a greater 
portion is emitted as chlorine; and (3) the mass emission rate of 
hydrogen chloride and chlorine gas would increase if the stack gas 
flowrate increases.
    Because of these concerns, the more appropriate metric for a risk-
based standard for total chlorine would be the toxicity-weighted HCl-
equivalent emission rate discussed above in Section C.1.
    To achieve our dual objective of establishing a protective risk-
based emission standard expressed as a toxicity-weighted HCl-equivalent 
emission rate (lb/hr) and ensuring that the standard does not allow 
total chlorine emission concentrations (ppmv) higher than the current 
interim standard of 130 ppmv, we propose that an HCl-equivalent 
emission rate limit be established that is achievable by all cement 
facilities. This would be an HCl-equivalent emission rate for which on-
site cement kiln emissions of hydrogen chloride and chlorine gas do not 
exceed a Hazard Index of 1.0. To make this determination, facilities 
would assume that emissions of hydrogen chloride and chlorine gas 
partition at the same ratio as measured during the most recent 
compliance test. Finally, the HCl-equivalent emission rate limit would 
be capped, if necessary, at a limit that ensures that total chlorine 
concentrations for each kiln do not exceed 130 ppmv.
    If this information and supporting documentation is provided to us, 
we would promulgate a toxicity-weighted HCl-equivalent emission rate 
that would be applicable to cement kilns.
    On a related matter, we evaluated whether using hydrogen chloride 
and chlorine gas emissions data obtained with stack sampling Method 26/
26A to project hydrogen chloride and chlorine gas emissions in CKRC's 
analysis compromised the results. Method 26/26A is known to 
underestimate hydrogen chloride emissions from cement kilns.\187\ We 
discuss above in Section F.2 concerns about Method 26/26A and the 
rationale for proposing to require sources to use methods other than 
Method 26/26A to measure emissions of hydrogen chloride and chlorine 
gas for compliance with risk-based standards. Briefly, Method 26/26A 
results for hydrogen chloride are biased low for cement kilns, although 
results for chlorine gas are unaffected. Even though CKRC used Method 
26A results to apportion the 130 ppmv total chlorine assumed emissions 
between hydrogen chloride and chlorine gas for each source, the 
calculated Hazard Index values are not compromised. Given that the 
hydrogen chloride emission levels are biased low, the chlorine gas/
hydrogen chloride ratio that CKRC used to apportion the 130 ppmv total 
chlorine emissions between chlorine gas and hydrogen chloride emissions 
for each source is biased high. Thus, CKRC projected chlorine gas 
emissions that are biased high and hydrogen chloride emissions that are 
biased low. These biases result in calculating conservative (i.e., 
higher than actual) Hazard Index values because the health threshold 
values are lower for chlorine gas than for hydrogen chloride.\188\ 
Thus, actual Hazard Index values at an emission level of 130 ppmv total 
chlorine would be lower than those that CKRC calculated.
---------------------------------------------------------------------------

    \187\ See 63 FR at 14196 (March 24, 1998).
    \188\ For the same reasons, HCl-equivalent emission rates that 
CKRC may use in an eligibility demonstration for the source category 
would be biased conservatively high.
---------------------------------------------------------------------------

XIV. How Did EPA Determine Testing and Monitoring Requirements for the 
Proposed Rule?

    The CAA requires us to develop regulations that include monitoring 
and testing requirements. CAA section 114 (a) (3). The purpose of these 
requirements is to allow us to determine whether an affected source is 
operating in compliance with the rule.
    We propose testing and monitoring requirements for solid fuel-fired 
boilers, liquid fuel-fired boilers and hydrochloric acid production 
furnaces that are identical to those applicable to incinerators, cement 
kilns, and lightweight aggregate kilns under Sec. Sec.  63.1207, 
63.1208, and 63.1209.\189\ Please note, however, that we discuss below 
a proposed requirement for boilers that would not be subject to a 
numerical dioxin/furan emission standard to conduct a one-time test for 
dioxin/furan emissions. In addition, in Part Three of today's preamble, 
we request comment on, or propose revisions to, several compliance 
requirements. Any amendments to the compliance requirements that we 
promulgate would be applicable to all hazardous waste combustors. In 
addition, we discuss below in this

[[Page 21307]]

section proposed compliance procedures for emission standards that 
would be based on normal rather than compliance test data and that 
would be applicable to all hazardous waste combustors subject to such a 
standard. Finally, we discuss below in this section proposed compliance 
procedures for emission standards based on hazardous waste thermal 
emissions that would be applicable to all hazardous waste combustors.
---------------------------------------------------------------------------

    \189\ Please note that we also propose to revise the existing 
schedule for the initial comprehensive performance test for 
incinerators, cement kilns, and lightweight aggregate kilns. Under 
the proposed revised schedule, owners and operators of incinerators, 
cement kilns, and lightweight aggregate kilns would be required to 
conduct the initial comprehensive performance test to document 
compliance with the replacement standards proposed today (Sec. Sec.  
63.1219, 63.1220, and 63.1221) within 12 months of the compliance 
date. See discussion in Part Three, Section I.F.
---------------------------------------------------------------------------

    The rationale for the testing and monitoring requirements, and 
implementation of the requirements, is the same as discussed in the 
rulemakings promulgating those requirements for hazardous waste-burning 
incinerators, cement kilns, and lightweight aggregate kilns, and as 
discussed in Part Three of today's preamble. See 61 FR 43501 (August 
23, 1996), 62 FR 24212 (May 2, 1997), 67 FR 6791 (February 13, 2002), 
and 67 FR 6967 (February 14, 2002). For this reason, we only summarize 
those identical requirements and our rationale for them in today's 
notice.\190\
---------------------------------------------------------------------------

    \190\ For this reason, in the technical support documents for 
today's proposed rule we also refer extensively to the technical 
support documents for the Phase I rule.
---------------------------------------------------------------------------

A. What Is the Rationale for the Proposed Testing Requirements?

    The proposed rule requires solid fuel-fired boilers and liquid 
fuel-fired boilers to perform an initial comprehensive performance test 
for dioxin/furan,\191\ mercury, particulate matter, semivolatile 
metals, low volatile metals, and total chloride to demonstrate 
compliance with emission standards. Hydrochloric acid production 
furnaces would be required to perform an initial comprehensive 
performance test for dioxin/furan and total chloride to demonstrate 
compliance with emission standards. All three source categories are 
also subject to the destruction and removal efficiency standard. 
Compliance with the destruction and removal efficiency standard, 
however, is based on a one-time emissions test, and previous 
destruction and removal efficiency testing under RCRA requirements may 
be used for that demonstration if design, operation, or maintenance of 
the source has not changed in a manner that could adversely affect 
combustion efficiency and, thus, destruction and removal efficiency. 
Finally, all three source categories would be required to demonstrate 
compliance with the carbon monoxide/hydrocarbon emission standard 
during the comprehensive performance test (and at all other times).
---------------------------------------------------------------------------

    \191\ Those boilers that would be subject to a numerical dioxin/
furan standard (i.e., liquid fuel-fired boilers equipped with an 
electrostatic precipitator or fabric filter) would be required to 
conduct periodic comprehensive and confirmatory testing. Other 
boilers would be required to conduct a one-time test for dioxin/
furan emissions under the conditions discussed below in the text.
---------------------------------------------------------------------------

    The comprehensive performance test would be conducted every five 
years to ensure that the performance of the air pollution control 
device has not deteriorated and that other factors that may affect 
emissions have not caused an increase in emissions above the standards.
    The proposed rule also requires confirmatory testing to ensure 
compliance with the dioxin/furan emission standards, the test to be 
conducted mid-way between comprehensive performance tests when 
operating under typical conditions rather than at performance test 
conditions. More frequent confirmatory testing for dioxin/furan is 
needed because dioxin/furan emissions can be affected by various and 
interrelated factors, some of which are not fully understood, and 
because of the particular health hazard posed by emissions of dioxin/
furan.
    To ensure continuous compliance with the emissions standards, you 
would be required to establish limits on key operating parameters 
susceptible to continuous monitoring. The limits would be based on 
operating values achieved during the comprehensive performance test 
when the source successfully demonstrates compliance.\192\ Because 
operating limits are calibrated based on operations during the 
comprehensive performance test, sources generally operate at the upper 
end of the range of normal operations during these tests. These 
proposed requirements are discussed below in Section XII.C.
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    \192\ Because the dioxin/furan confirmatory test is conducted 
under operating conditions that are within the range of normal 
operations rather than at the upper end of the range of normal 
operations as during a comprehensive performance test, you would not 
reestablish operating conditions for dioxin/furan based on the 
confirmatory performance test.
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B. What Are the Dioxin/Furan Testing Requirements for Boilers That 
Would Not Be Subject to a Numerical Dioxin/Furan Emission Standard?

    As explained earlier, we are not proposing numerical dioxin/furan 
emission standards for solid fuel-fired boilers and for those liquid 
fuel-fired boilers that are equipped with wet scrubbers or no 
particulate control device. Rather, those boilers would be subject to 
the carbon monoxide/hydrocarbon emission standard and the destruction 
and removal efficiency standard to help minimize dioxin/furan 
emissions. See discussion in Part Two, Sections X.A and XI.A.
    We propose that solid fuel-fired boilers and those liquid fuel-
fired boilers that would not be subject to a numerical dioxin/furan 
emission standard conduct a one-time dioxin/furan emission test to 
quantify the effectiveness of today's proposed surrogate dioxin/furan 
emission controls. This test would be performed no later than the 
initial comprehensive performance test required under the proposed 
standards. The results of this one-time test would be reported with the 
test results for the first comprehensive performance test. See proposed 
Sec.  3.1207(b)(3).
1. What Is the Rationale for Requiring the Test?
    We are adopting this provision pursuant to our authority in CAA 
section 114 (a)(1)(D), which allows EPA to require ``any person * * * 
who is subject to any requirement of this chapter'' (which includes 
section 112) on a one-time, periodic or continuous basis, to ``sample 
such emissions (in accordance with such procedures or methods, at such 
locations, at such intervals, during such periods and in such manner as 
the Administrator shall prescribe)''. The purpose of such monitoring is 
``developing or assisting in the development of'' standards under 
various provisions of the Act, including section 112. In this case, 
monitoring will assist in making determinations under both section 
112(d)(6) and section 112(f), which could lead to development of 
standards under either or both of these provisions.
    Section 112(d)(6) of the Act requires us to ``review, and revise as 
necessary emission standards promulgated under this section no less 
than every eight years.'' We believe testing that results from 
compliance with today's proposed standards will, in nearly all cases, 
establish an adequate database for us to perform this review. However, 
we would not have sufficient dioxin/furan emissions data for those 
boilers that are subject to the carbon monoxide/hydrocarbon standard 
and destruction and removal efficiency standard in lieu of a numerical 
dioxin/furan standard. We have data from approximately one-third of the 
boilers that are not subject to a numerical dioxin/furan standard. 
Although those data indicate that these sources emit low concentrations 
of dioxin/furan despite the absence of any dioxin/furan control 
equipment, we are concerned about extrapolating this performance to the 
entire universe of

[[Page 21308]]

the subject boilers because our data set may not be statistically 
random and the potential hazard posed by dioxin/furan is high. In fact, 
the design of these sources would seem to have the potential for 
formation of significant dioxin/furan concentrations.\193\ We think 
this proposed testing would add a one-time cost of approximately 
$10,000 for each source for which dioxin/furan test data are not 
already available, and the cost appears reasonable to enable us to meet 
our section 112(d)(6) and 112(f) mandates. Section 112(d)(6) requires 
EPA, at specified times, to determine if further technology-based 
emission reductions are warranted. Quantified dioxin/furan emission 
information from these sources will assist in this determination. 
Section 112(f) requires EPA (among other things) to determine if 
emissions from all sources subject to section 112(d) standards must be 
further reduced in order to assure an ample margin of safety to protect 
public health. Having actual emission data from these sources obviously 
will assist in making the required section 112(f) determinations for 
these sources.
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    \193\ Incinerators equipped with waste heat recovery boilers are 
known to emit high levels of dioxin/furan, and hydrochloric acid 
production furnaces with waste heat recovery boilers can also emit 
high levels of dioxin/furan. Because the mechanisms that affect 
formation and control of dioxin/furan are complex and not fully 
understood, we are concerned that some of the factors that cause 
high dioxin/furan emissions from incinerators and hydrochloric acid 
production furnaces equipped with waste heat recovery boilers may 
also affect dioxin/furan emissions from boilers.
---------------------------------------------------------------------------

2. What Are the Operating Requirements for the Test?
    You must perform the dioxin/furan test under feed and operating 
conditions that are most likely to maximize dioxin/furan emissions, 
similar to a dioxin/furan comprehensive performance test. Based on 
currently available research, the following factors should be 
considered for the testing: (1) Dioxin/furan testing should be 
conducted at the point in the maintenance cycle for the boiler when the 
boiler tubes are more fouled and soot-laden, and not after maintenance 
involving soot or ash removal from the tubes; (2) dioxin/furan testing 
should be performed following (or during) a period of feeding normal or 
greater quantities of metals; (3) dioxin/furan testing should be 
performed while feeding normal or greater quantities of chlorine; (4) 
the flue gas temperature in some portion of the heat recovery section 
of the boiler should be within the dioxin formation temperature window 
of 750 to 400[deg]F during the testing; (5) the testing should not be 
conducted under optimal combustion conditions; (6) for units equipped 
with wet air pollution control systems, the testing should be conducted 
after a high solids loading has developed in the scrubber system; and 
(7) for solid fuel-fired boilers, the sulfur content of the coal should 
be equivalent to or lower than normal coal sulfur levels, and the gas 
temperature at the inlet to the electrostatic precipitator or fabric 
filter should be close to the operating limit. In addition, unless 
sulfur compounds are routinely fed to the unit, dioxin/furan testing 
should not be performed after a period of firing high sulfur fuel or 
injection of sulfur additives.
    The majority of these recommendations are based on research 
demonstrating that soot deposits can enhance dioxin/furan formation in 
the presence of chlorine and catalytic metal contaminants, with 
formation continuing even after cessation of those contaminant feeds to 
the system.194, 195 The boiler tube deposits serve as a sink 
and source for dioxin/furan reactants (catalytic metals and chlorine), 
and combined soot-copper deposits have been shown to cause more dioxin/
furan formation than a deposit of soot or copper alone. From analysis 
of soot deposits taken from different sections of a firetube boiler, 
the highest measured dioxin/furan concentrations were found in those 
deposits containing the highest concentrations of copper and chloride. 
Those same deposits were removed from the boiler passages where flue 
gas temperatures ranged from 600-300[deg]C, which is within the often-
cited optimal temperature region for dioxin/furan formation. Tube 
deposits have also been shown to have a negative effect on dioxin 
emissions when those deposits have been affected by sulfur dioxide, 
which is why dioxin/furan testing is not recommended following a period 
of feeding higher-than-normal levels of sulfur to the boiler.
---------------------------------------------------------------------------

    \194\ Lee, C.W.; Kilgroe, J.D.; Raghunathan, K. Environ. Eng. 
Sci. 1998, 15(1), 71-84.
    \195\ Gullett, B.K.; Touati, A.; Lee, C.W. Environ. Sci. 
Technol. 2000, 34, 2069-2074.
---------------------------------------------------------------------------

    The recommendation not to test under optimal combustion conditions 
has been explained previously in the September 1999 Final Rule preamble 
discussion. See 64 FR at 52937. Good combustion practices minimize 
dioxin/furan emissions by: (1) Destroying trace dioxins/furans that may 
be present in feed streams; (2) minimizing gas-phase formation of 
dioxins/furans; and (3) minimizing dioxin/furan precursors that may 
enhance post-combustion formation.
    For units equipped with wet air pollution control systems, it is 
also recommended that testing be conducted after a high solids loading 
has developed in the scrubber system. Research conducted to explore the 
phenomenon of increased dioxin/furan flue gas concentrations across 
some wet scrubber systems has shown differing flue gas outlet dioxin/
furan homologue profiles than flue gas inlet profiles to the scrubber, 
but similar flue gas outlet homologue profiles to scrubber suspended 
solids and sludge profiles.\196\ This result suggests that some type of 
memory effect may be associated with suspended solids in a scrubber 
system which can cause higher dioxin/furans emissions.
---------------------------------------------------------------------------

    \196\ Takaoka, M.; Liao, P.; Takeda, N.; Fujiwara, T.; Oshita, 
K. Chemosphere 2003, 53, 153-161.
---------------------------------------------------------------------------

    You may use data-in-lieu of testing to document dioxin/furan 
emissions for similar on-site boilers. In addition, dioxin/furan 
emission data from previous testing would be acceptable, provided the 
test was performed in a manner likely to maximize dioxin/furan 
emissions.

C. What Are the Proposed Test Methods?

    The proposed emission standards are method-based standards, meaning 
that the stack test methods used for compliance must be the same as 
those used to generate the emissions data we used to calculate the 
standards. Because alternative stack methods may report lower 
emissions, it is appropriate to require use of the same methods for 
compliance as sources used to generate the emissions data in our data 
base.
    For this reason, you would be required to use the following stack 
test methods for compliance: (1) Method 29 for mercury, semivolatile 
metals, and low volatile metals; and (2) Method 26/26A for total 
chlorine.\197\ For dioxin/furan, the rule would require use of Method 
0023A unless you receive approval to use Method 23. We discuss the 
rationale for allowing site-specific approvals to use Method 23 in Part 
Three, Section II.D of today's preamble. In addition, for particulate 
matter, you would be required to use either Method 5, the method used 
to generate the data in our data base or Method 5i. We allow use of 
Method 5i because it is more

[[Page 21309]]

precise than Method 5 at lower particulate matter loadings.
---------------------------------------------------------------------------

    \197\ Please note that we discuss in Section XIII of the 
preamble above concerns with the accuracy of M26/26A for measuring 
emissions of total chlorine for cement kilns. As we explain there, 
although M26/26A is appropriate for demonstrating compliance with 
the MACT standards for cement kilns, it is not acceptable for 
demonstrating compliance with risk-based standards developed under 
authority of section 112(d)(4) of the Act.
---------------------------------------------------------------------------

    These test methods are codified in 40 CFR part 60, appendix A.\198\
---------------------------------------------------------------------------

    \198\ Method 0023A, however, is included in ``Test Methods for 
Evaluating Solid Waste, Physical/Chemical Methods,'' EPA Publication 
SW-846 Third Edition (November 1986), as amended.
---------------------------------------------------------------------------

D. What Is the Rationale for the Proposed Continuous Monitoring 
Requirements?

    The most direct means of ensuring compliance with emissions limits 
is the use of continuous emission monitoring systems (CEMS). We 
consider other options when CEMS are not available or when we consider 
the impacts of including such requirements unreasonable. When 
monitoring options other than CEMS are considered, it is often 
necessary for us to balance more reasonable costs against the quality 
or accuracy of the emissions monitoring data. Although monitoring 
operating parameters cannot provide a direct measurement of emissions, 
it is often a suitable substitute for CEMS. The information provided 
can be used to ensure that air pollution control equipment is operating 
properly. Because most parameter requirements are calibrated during 
comprehensive performance testing,\199\ they provide a reasonable 
surrogate for direct monitoring of emissions. This information 
reasonably assures the public that the reductions envisioned by the 
proposed rule are being achieved.
---------------------------------------------------------------------------

    \199\ Except that some parameters are limited based on the 
recommendations/specifications of the manufacturer of the control 
device.
---------------------------------------------------------------------------

1. What CEMS Requirements Did EPA Consider?
    To comply with the carbon monoxide or hydrocarbon emission limits, 
you would be required to use a carbon monoxide or hydrocarbon CEMS as 
well as an oxygen CEMS to correct the carbon monoxide or hydrocarbon 
values to 7% oxygen. See Sec.  63.1209(a). Because boilers and 
hydrochloric acid production furnaces are currently required to use 
these CEMS to comply with existing RCRA emission standards for carbon 
monoxide or hydrocarbons, there would be a minimal incremental 
compliance cost.\200\
---------------------------------------------------------------------------

    \200\ If you elect to comply with the carbon monoxide standard 
rather than the hydrocarbon standard, you would be required to 
document that hydrocarbon emissions during the comprehensive 
performance test meet the standard.
---------------------------------------------------------------------------

    We also evaluated the cost of applying hydrogen chloride CEMS to 
boilers and hydrochloric acid production furnaces. We estimate the 
capital costs for hydrogen chloride CEMS to be $88,000 per unit and 
annualized costs to be $33,000 per unit. We determined these costs 
would be unreasonably high considering: (1) The CEMS detects hydrogen 
chloride but not chlorine gas, so that compliance with the total 
chlorine emission standard could not be monitored; (2) the 
effectiveness of operating parameter limits to ensure compliance with 
the emission standard for total chlorine; and (3) the relatively low 
level of hazard posed by emissions of total chlorine.
    Finally, we conclude that the use of CEMS to document compliance 
with particulate matter or metal HAP emission standards has not been 
demonstrated on hazardous waste combustors in the United States.
2. What Operating Parameter Limits Would Be Required?
    To ensure continuous compliance with the proposed emission limits, 
you would be required to establish limits on key operating parameters 
and continuously monitor the parameters including: feedrate of metals, 
chlorine, and, for some source categories, ash; key combustor operating 
parameters; and key operating parameters of the control device. See 
Sec.  63.1209(j-o). You would also be required to document monitoring 
by recordkeeping and reporting. We selected the following requirements 
based on reasonable cost, ease of execution, and usefulness of the 
resulting data to both owners and operators and EPA for ensuring 
continuous compliance with the emission limits.
    To ensure continuous compliance with the dioxin/furan emission 
limit, you would be required to establish: (1) A limit on maximum gas 
temperature at the inlet to a dry particulate matter control device; 
(2) a limit on minimum combustion chamber temperature; (3) a limit on 
maximum flue gas flowrate or production rate; (4) a limit on maximum 
waste feedrate; (5) if your combustor is equipped with an activated 
carbon injection system: limits on the particulate matter control 
device, as discussed below; a limit on minimum carbon injection rate; a 
limit on minimum carrier fluid flowrate or pressure drop; and you must 
specify and use the brand (i.e., manufacturer) and type of carbon used 
during the comprehensive performance test, unless you document key 
parameters that affect adsorption and establish limits on those 
parameters based on the carbon used in the comprehensive performance 
test; (6) if your combustor is equipped with a carbon bed: you must 
monitor the bed life to ensure that it has not reached the end of its 
useful life to minimize dioxin/furan (and mercury) emissions at least 
to the levels required by the emission standards; you must replace the 
bed or bed segment before it has reached the end of its useful life; 
you must specify and use the brand (i.e., manufacturer) and type of 
carbon used during the comprehensive performance test, unless you 
document key parameters that affect adsorption and establish limits on 
those parameters based on the carbon used in the comprehensive 
performance test; and you must establish a limit on maximum gas 
temperature either at the bed inlet or outlet; (7) if your combustor is 
equipped with a catalytic oxidizer: limits on minimum and maximum gas 
temperature at the inlet to the catalyst; you must replace the oxidizer 
when it has reached the maximum service time specified by the 
manufacturer; and when replacing the catalyst, the new catalyst must be 
equivalent to or better than the one used during the previous 
comprehensive performance test as measured by catalytic metal loading 
for each metal, space time, and substrate construction; (8) if you feed 
a dioxin/furan inhibitor into the combustion system: a limit on minimum 
inhibitor feedrate; and you must specify and use the brand (i.e., 
manufacturer) and type of inhibitor used during the comprehensive 
performance test, unless you document key parameters that affect the 
effectiveness of the inhibitor and establish limits on those parameters 
based on the inhibitor used in the comprehensive performance test. See 
Sec.  63.1209(k).
    To ensure continuous compliance with the mercury emission limit, 
owners and operators of boilers would be required to establish: (1) A 
limit on the total feedrate of mercury in all feedstreams for solid 
fuel-fired boilers, and a limit on mercury in hazardous waste 
feedstreams per million Btu of hazardous waste fired for liquid-fuel-
fired boilers; \201,\ \202\ (2) if your boiler is equipped with a wet 
scrubber, limits prescribed for control of total chlorine with a wet 
scrubber, except for a limit on minimum pH of the scrubber water; (3) 
if your boiler is equipped with an activated carbon injection system, 
limits on the particulate matter control device as discussed below, and 
limits on the activated carbon injection system as

[[Page 21310]]

discussed above for dioxin/furan; and (4) if your boiler is equipped 
with an activated carbon bed, limits on the carbon bed as discussed 
above for dioxin/furan.
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    \201\ This is because the mercury emission standard for liquid 
fuel-fired boilers is a hazardous waste thermal emission 
concentration. Liquid fuel-fired boilers would also be required to 
monitor the heating value of hazardous waste feeds to ensure 
compliance with the hazardous waste thermal emission concentration.
    \202\ The mercury feedrate limit would be based on levels fed 
during the comprehensive performance test unless the regulatory 
authority approves a request for you to extrapolate to a higher 
allowable feedrate (and emission rate) limit.
---------------------------------------------------------------------------

    You may comply with mercury feedrate limits only, however, if you 
elect to assume that all mercury in the feed is emitted. For solid 
fuel-fired boilers, you would assume that all mercury in all 
feedstreams is emitted under this alternative approach. You would also 
establish a limit on minimum flue gas flowrate to ensure compliance 
with the mercury emission standard. For liquid fuel-fired boilers where 
the mercury emission standard is expressed as hazardous waste thermal 
emissions, you would assume that all mercury in all hazardous waste 
feedstreams is emitted. You would have to comply with a hazardous waste 
thermal feed concentration that would be expressed as the mass of 
mercury in the hazardous waste per million Btu heat input contributed 
by the hazardous waste. Also, please note that these compliance 
requirements would not apply to hydrochloric acid production furnaces 
because (as explained earlier) we propose to use the total chlorine 
standard as a surrogate for the mercury, particulate matter, 
semivolatile metal, and low volatile metal standards for these sources. 
See Sec.  63.1209(l).
    To ensure continuous compliance with the particulate matter 
emission limit, you would be required to establish: (1) Limits on the 
control device operating parameters; (2) a limit on maximum flue gas 
flowrate or production rate; and a limit on maximum ash feedrate. If 
your boiler is equipped with a wet scrubber, you would establish limits 
on: (1) For high energy scrubbers only, minimum pressure drop across 
the scrubber and either minimum liquid to gas ratio or minimum scrubber 
water flowrate and maximum flue gas flowrate; and (2) for all 
scrubbers, the solids content of the scrubber liquid or a minimum 
blowdown rate. If your boiler is equipped with an electrostatic 
precipitator, ionizing wet scrubber, or fabric filter, please note that 
we discuss in Part Three, Section II.I. below proposed compliance 
parameters for these control devices. Briefly, if your boiler is 
equipped with a fabric filter, you must comply with bag leak detection 
system requirements. If your boiler is equipped with an electrostatic 
precipitator or ionizing wet scrubber, you must either: (1) Install and 
operate a particulate matter loading detector as a process monitor to 
indicate when you must take corrective measures; or (2) establish 
limits on key operating parameters, on a site-specific basis, that are 
representative and reliable indicators that the control device is 
operating within the same range of conditions as during the 
comprehensive performance test, and link those operating limits to the 
automatic waste feed cutoff system. Please note that the particulate 
matter compliance requirements would not apply to hydrochloric acid 
production furnaces, as discussed above. See Sec.  63.1209(m).
    To ensure continuous compliance with the semivolatile and low 
volatile metal emission limits, you would be required to establish: (1) 
A limit on the maximum inlet temperature to the primary dry particulate 
matter control device; (2) a limit on maximum feedrate of semivolatile 
and low volatile metals from all feedstreams for solid fuel-fired 
boilers, and a limit on semivolatile metals and low volatile metals in 
hazardous waste feedstreams per million Btu of hazardous waste fired 
for liquid-fuel-fired boilers; 203, 204 (3) limits (or 
process monitors) on the particulate matter control device as discussed 
above; (4) a limit on maximum feedrate of total chlorine or chloride in 
all feedstreams; and (5) a limit on maximum flue gas flowrate or 
production rate. You may comply with semivolatile and low volatile 
metal feedrate limits only, however, if you elect to assume that all 
semivolatile and low volatile metals in the feed is emitted. For solid 
fuel-fired boilers, you would assume that all semivolatile and low 
volatile metals in all feedstreams are emitted under this alternative 
approach. You would also establish a limit on minimum flue gas flowrate 
to ensure compliance with the semi- and low volatile metals emission 
standard. For liquid fuel-fired boilers where the semivolatile and low 
volatile metals emission standards are expressed as hazardous waste 
thermal emissions, you would assume that all semivolatile and low 
volatile metals in all hazardous waste feedstreams are emitted. You 
would have to comply with a hazardous waste thermal feed concentration 
that would be expressed as the mass of semivolatile (or low volatile) 
metals in the hazardous waste per million Btu heat input contributed by 
the hazardous waste. Also, please note that the semivolatile metal and 
low volatile metal compliance requirements would not apply to 
hydrochloric acid production furnaces, as discussed above. See Sec.  
63.1209(n).
---------------------------------------------------------------------------

    \203\ This is because the semivolatile metal and low volatile 
metal emission standards for liquid fuel-fired boilers are hazardous 
waste thermal emission concentrations. You would also be required to 
monitor the heating value of hazardous waste feedstreams to ensure 
compliance with the hazardous waste thermal emission concentration.
    \204\ The semivolatile and low volatile metal feedrate limits 
would be based on levels fed during the comprehensive performance 
test unless the regulatory authority approves a request for you to 
extrapolate to higher allowable feedrate (and emission rate) limits. 
Please note that the semivolatile and low volatile metal feed limits 
for liquid fuel-fired boilers are hazardous waste thermal 
concentration limits (pounds of metal per million Btu), not mass 
feedrate limits, given that the emission standards are expressed as 
hazardous waste thermal emissions.
---------------------------------------------------------------------------

    To ensure continuous compliance with the total chlorine emission 
limit, you would be required to establish: (1) A limit on maximum 
feedrate of total chlorine and chloride from all feedstreams for solid 
fuel-fired boilers, and a limit on total chlorine and chloride in 
hazardous waste feedstreams per million Btu of hazardous waste fired 
for liquid-fuel-fired boilers;\205\ (2) a limit on maximum flue gas 
flowrate or production rate; (3) if your combustor is equipped with a 
high or low energy wet scrubber: a limit on minimum pH of the scrubber 
water; a limit on either the minimum liquid to gas ratio or the minimum 
scrubber water flowrate and maximum flue gas flowrate; (4) if your 
combustor is equipped with a high energy wet scrubber, a limit on 
minimum pressure drop across the scrubber; (5) if your combustor is 
equipped with a low energy wet scrubber: a limit on minimum pressure 
drop across the scrubber; and a limit on minimum liquid feed pressure 
to the scrubber; and (6) if your combustor is equipped with a dry 
scrubber: a limit on minimum sorbent feedrate; a limit on minimum 
carrier fluid flowrate or nozzle pressure drop; and you must specify 
and use the brand (i.e., manufacturer) and type of sorbent used during 
the comprehensive performance test, unless you document key parameters 
that affect the effectiveness of the sorbent and establish limits on 
those parameters based on the sorbent used in the comprehensive 
performance test. If your combustor is equipped with an ionizing wet 
scrubber, please note that we discuss in Part Three, Section II.I. 
below proposed compliance parameters for this control device. Briefly, 
if your combustor is equipped with an ionizing wet scrubber, you must 
either: (1) Install and operate a particulate matter loading detector 
as a process monitor to indicate when you must take corrective 
measures; or (2)

[[Page 21311]]

establish limits on key operating parameters, on a site-specific basis, 
that are representative and reliable indicators that the control device 
is operating within the same range of conditions as during the 
comprehensive performance test, and link those operating limits to the 
automatic waste feed cutoff system.
---------------------------------------------------------------------------

    \205\ This is because the total chlorine emission standard for 
liquid fuel-fired boilers is a hazardous waste thermal emission 
concentration. You would also be required to monitor the heating 
value of hazardous waste feedstreams to ensure compliance with the 
hazardous waste thermal emission standard.
---------------------------------------------------------------------------

    You may comply with a total chlorine and chloride feedrate limit 
only, however, if you elect to assume that all chlorine in the feed is 
emitted. For solid fuel-fired boilers, you would assume that all 
chlorine in all feedstreams is emitted under this alternative approach. 
You would also establish a limit on minimum flue gas flowrate to ensure 
compliance with the total chlorine standard. For liquid fuel-fired 
boilers where the total chlorine emission standard is expressed as 
hazardous waste thermal emissions, you would assume that all chlorine 
in all hazardous waste feedstreams is emitted. You would have to comply 
with a hazardous waste thermal feed concentration that would be 
expressed as the mass of chlorine in the hazardous waste per million 
Btu heat input contributed by the hazardous waste. See Sec.  
63.1209(o).
    To ensure continuous compliance with the destruction and removal 
efficiency standard, you would be required to: (1) Establish a limit on 
minimum combustion chamber temperature; (2) establish a limit on 
maximum flue gas flowrate or production rate; (3) establish a limit on 
maximum hazardous waste feedrate; and (4) specify operating parameters 
and limits to ensure that good operation of each hazardous waste firing 
system is maintained. See Sec.  63.1209(j).

E. What Are the Averaging Periods for the Operating Parameter Limits, 
and How Are Performance Test Data Averaged To Calculate the Limits?

    Except as discussed in Section XIV.F below, we propose that owners 
and operators of solid fuel-fired boilers, liquid fuel-fired boilers, 
and hydrochloric acid production furnaces establish averaging periods 
for the operating parameter limits and calculate the limits from 
comprehensive performance test data under the same approaches required 
currently for incinerators, cement kilns, and lightweight aggregate 
kilns. A detailed discussion of how those approaches work, and the 
rationale for them, are provided at 64 FR at 52919-22 (September 30, 
1999). That discussion is summarized below.
    We propose the following averaging periods: (1) No averaging period 
(i.e., instantaneous monitoring) for maximum combustion chamber 
pressure to control combustion system leaks; \206\ (2) 12-hour rolling 
averages for maximum feedrate of mercury, semivolatile metals, low 
volatile metals, total chlorine and chloride, and ash; and (3) one-hour 
rolling averages for all other operating parameters. We propose a 12-
hour rolling average for metal, total chlorine and chloride, and ash 
feedrate limits to correspond to the potential duration of three runs 
of a comprehensive performance test, considering that feedrate and 
emissions, are, for the most part, linearly related. We propose an 
hourly rolling average limit for all parameters that are based on 
operating data from the comprehensive performance test, except 
combustion chamber pressure and metal, chlorine, and ash feedrate 
limits. Hourly rolling averages are appropriate 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 
HAP or HAP surrogates.
---------------------------------------------------------------------------

    \206\ Please note, however, that we request comment on the 
appropriateness of these combustion system leak requirements in Part 
Three of today's preamble.
---------------------------------------------------------------------------

    We propose two approaches to calculate limits for 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 production rate and hazardous waste 
feedrate--would be 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, would be based on the 
average level occurring during the comprehensive performance test. We 
conclude 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 emissions results are 
determined.\207\ We also conclude that limits based on the average 
level occurring during the comprehensive performance are readily 
achievable. This is because sources generally conduct performance 
testing at the extreme upper end of the range of normal operations to 
provide the operating flexibility needed after establishing operating 
parameter limits. Because sources can readily control (during the 
performance test and thereafter) the parameters for which limits are 
established, the operating limits based on the average of the 
performance test runs should be readily achievable under routine 
operations.
---------------------------------------------------------------------------

    \207\ Manual method emission test results for each run represent 
average emissions over the entire run.
---------------------------------------------------------------------------

F. How Would Sources Comply With Emissions Standards Based on Normal 
Emissions?

    Several proposed emission standards would be based on emissions 
that are within the normal range of operations for the source rather 
than on compliance test emissions that represent the extreme upper end 
of the range of normal emissions: \208\ mercury standards for cement 
kilns, lightweight aggregate kilns, and liquid fuel-fired boilers, and 
semivolatile metal emissions for liquid fuel-fired boilers. To ensure 
compliance with emission standards based on normal emissions data, you 
would document during the comprehensive performance test a system 
removal efficiency for the metals and back-calculate from the emission 
standard a maximum metal feedrate limit that must not be exceeded on an 
annual rolling average. If your source is not equipped with an emission 
control system (such as activated carbon to control mercury) for the 
metals in question, however, you must assume zero system removal 
efficiency. This is because a source that is not equipped with an 
emission control system may be able to document a positive system 
removal efficiency, but it is not likely to be reproducible. It is 
likely to be an artifact of the calculation of emissions and feeds 
rather than a removal efficiency that is reliable and reproducible.
---------------------------------------------------------------------------

    \208\ Compliance test emissions represent the upper range of 
emissions from a source because operating parameter limits for the 
HAP or HAP surrogate are established based on this compliance test.
---------------------------------------------------------------------------

    To ensure that you can calculate a valid, reproducible system 
removal efficiency for sources equipped with a control system that 
effectively controls the metal in question, you may need to spike 
metals in the feed during the comprehensive performance test at levels 
that may result in emissions that are higher than the standard. This 
would be acceptable because compliance with an emission standard 
derived from normal emissions data is based on compliance with an 
annual average feedrate limit calculated as prescribed here, rather 
than compliance with the emission standard during the comprehensive 
performance test.
    We propose a one-year averaging period for the metal feedrate limit

[[Page 21312]]

because the emission standard represents normal, average emissions. 
Although the averaging period could be substantially shorter or longer, 
a one-year averaging period is within the range of reasonable averaging 
periods and would be readily achievable for a standard based on normal 
emissions. The annual rolling average metal feedrate would be updated 
each hour based on the average of the 60 previous 1-minute averages.
    We propose to retain the hourly rolling average requirement for the 
other operating parameter limits, however, for the reasons discussed 
above (i.e., to be conservative given the nonlinear relationship 
between the operating parameter and emissions, and because the limits 
would be readily achievable).

G. How Would Sources Comply With Emission Standards Expressed as 
Hazardous Waste Thermal Emissions?

    Several proposed emission standards would be expressed as hazardous 
waste thermal emissions: mass of pollutant emissions attributable to 
the hazardous waste feed per million Btu of hazardous waste fed to the 
combustor.
    To demonstrate compliance with a hazardous waste thermal emissions-
based standard during a comprehensive performance test, you would 
calculate the hazardous waste thermal emissions by apportioning mass 
emissions of mercury, semivolatile metals, low volatile metals, or 
total chlorine according to the ratio of the mass feedrate of mercury, 
semivolatile metals, low volatile metals, or total chlorine and 
chloride from hazardous waste feedstreams to the feedrate for all 
feedstreams and dividing by the heat input rate (i.e., million Btu/hr) 
attributable to the hazardous waste.
    To ensure continuous compliance with the hazardous waste thermal 
emissions-based standard, you would calculate an operating limit based 
on the hazardous waste thermal feed concentration during the 
performance test.\209\ The hazardous waste thermal feed concentration 
limit would be calculated as the mass feedrate (lb/hr) of mercury, 
semivolatile metals, low volatile metals, or total chlorine and 
chloride from hazardous waste feedstreams divided by the heat input 
rate (million Btu/hr) from hazardous waste feedstreams. For compliance, 
you would continuously monitor the feedrate of hazardous waste on a 12-
hour rolling average updated each minute or, for standards based on 
normal emissions, on an annual rolling average updated each hour. You 
must know the concentration of mercury, semivolatile metals, low 
volatile metals, or total chlorine and chloride in the hazardous waste 
at all times, and the heating value of the hazardous waste at all 
times. Using this information, you would calculate and record the 
hazardous waste thermal feed concentration on a 12-hour rolling 
average, or for standards based on normal emissions, on an annual 
rolling average updated each hour.
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    \209\ If the hazardous waste thermal emission standard is 
derived from normal rather than compliance test emissions data, 
however, the hazardous waste thermal feed concentration would be 
calculated as discussed above in Section F of the preamble.
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H. What Happens if My Thermal Emissions Standard Limits Emissions to 
Below the Detection Limit of the Stack Test Methods?

    Under today's proposed thermal emissions standards, the standard 
may limit emissions to levels that are below the analytical detection 
limit of the stack test method. For example, this may occur with the 
semi-volatile metals standard for liquid fuel boilers when allowable 
emission levels are below the analytical detection capabilities of 
Method 29 when the hazardous waste firing rate or heating value is low. 
To address this issue, we are requesting comment on an approach that 
would allow you to be in compliance with today's proposed thermal 
emission standards if certain sampling and analytical criteria are met.
    The first criterion would ensure that the test crew accumulates 
enough of the analyte (e.g., metal HAP) in the sample train to ensure 
that it is measurable by the laboratory. For example, the amount of HAP 
accumulated in a one hour sample may not be sufficient for the 
laboratory to quantify. On the other hand, a three hour test would be 
more likely to accumulate enough sample, since three times the amount 
of that HAP would be collected. Most Method 29 results that comprise 
our emissions database are from two to three hour samples. The first 
criterion would be met if the facility samples the flue gas for at 
least three hours for each run.
    The second criterion would ensure that the laboratory uses adequate 
quality assurance procedures to measure the HAP in the sample. Section 
13.2 of Method 29 provides the analytical detection limits for the 
various laboratory methods used to determine the amount of HAP 
accumulated in the sample. The second criterion would be met if the 
laboratory reports analytical detection limits that are less than or 
equal to those reported in section 13.2.
    The final criterion is that no HAP represented by the standard can 
be present above the analytical detection limit. For the semi-volatile 
metals standard, this means that neither lead nor cadmium could be 
present above the analytical detection limits for any run of the test. 
You would assume that the HAP is present at the full detection limit, 
if lead or cadmium are present above the analytical detection limit 
during any run of the test.
    If you wish to use this provision to demonstrate compliance with 
the standard, you would be required to show that all three criteria 
have been met in the Notification of Compliance sent to the appropriate 
permitting agency. You would not be required to provide advance notice 
or obtain prior approval from the permitting authority.

I. Are We Concerned About Possible Negative Biases Associated With 
Making Hydrogen Chloride Measurements in High Moisture Conditions?

    Several industry stakeholders have brought several scientific 
papers to our attention that indicate that Method 26A, used for 
compliance with the hydrogen chloride and chlorine gas standards, may 
have a significant low bias at wet stacks with low hydrogen chloride 
concentrations. These stakeholders have asked us not to establish 
standards for hydrogen chloride and chlorine standard below 20 ppmv to 
address this substantial negative bias.
    We agree that there was a concern early in the development and 
deployment of Method 26A that water droplets would not evaporate in the 
sampling train and would therefore dissolve hydrogen chloride in the 
sample train, before the hydrogen chloride can be caught by the 
impingers. EPA determined that this potential problem can be precluded 
by providing enough heat to the sample train to evaporate all water 
droplets that might collect in the sample probe or filter. Once the 
water is evaporated, the hydrogen chloride reenters the sample gas 
stream and is collected by the impingers.
    EPA's Office of Research and Development (ORD) performed laboratory 
studies to document and fully understand this problem. We also 
monitored the application of Method 26A and it's SW-846 equivalent to 
determine how these concerns may impact hydrogen chloride measurements 
made on wet stacks. Our conclusion is that the situations encountered 
in ORD's laboratory studies are not encountered when making stack test 
measurements.
    The Coalition for Responsible Waste Incineration, CRWI, provided a 
paper authored by Joette Steger, et al., which

[[Page 21313]]

illustrates this point. (See memorandum to docket for today's proposed 
rule from H. Scott Rauenzahn, U.S. EPA, entitled ``Method 26A and 
CRWI's Concerns,'' dated March 25, 2004.) Steger found that Method 26A 
has a significant negative bias when 40 to 50 percent of the water in 
the sample is in the form of water droplets. Under similar sample 
conditions, with 60 percent of the water in the form of droplets, 
Steger found that providing more heat to the sample train corrected the 
negative bias concern.
    We also checked our hydrogen chloride emissions data for hazardous 
waste combustors to see if water droplets could be present in the 
sample line. We found that water droplets could be present in three of 
our incinerator test conditions: 327C10 at 5 percent water droplets; 
808C1 at 12.5 percent water droplets; and 3024C1 at 8 percent water 
droplets. None of these stack conditions approach the 40 to 50 percent 
water droplets observed to be a problem by Steger. These stack gas 
conditions most closely resemble Steger's run B-5, with 10% water 
droplets. No negative bias was observed for Steger's run B-5. We 
conclude that this negative bias, while conceptually possible, is not 
encountered at hazardous waste combustors with wet stacks.
    We request comments on our analysis of these trade association's 
concerns, and request more data regarding this issue.

J. What Are the Other Proposed Compliance Requirements?

    We propose other compliance requirements for solid fuel-fired 
boilers, liquid fuel-fired boilers, and hydrochloric acid production 
furnaces that are the same as those currently in place at Sec.  63.1206 
for incinerators, cement kilns, and lightweight aggregate kilns. The 
rationale for the requirements is the same as discussed in previous 
rulemakings for incinerators, cement kilns, and lightweight aggregate 
kilns, and compliance procedures would be the same as currently 
required for those sources.
    The other compliance requirements include provisions for: startup, 
shutdown, and malfunction plans; operation and maintenance plans 
including a requirement for bag leak detector systems for fabric 
filters; automatic hazardous waste feed cutoff systems, including a 
requirement for exceedance reporting; combustion system leak 
requirements; changes in design, operation, or maintenance that could 
adversely affect compliance with emission standards; operator training 
and certification requirements; and requirements for sources that elect 
to comply with the carbon monoxide standard to document one-time that 
hydrocarbons also meet the hydrocarbon standard; and provisions 
allowing a one-time demonstration of compliance with the destruction 
and removal efficiency standard.
    Please note that we propose revisions to, or request comment on, 
some of these compliance requirements in Part Three of the preamble. 
Any revisions to these requirements that we might make in the final 
rule would be applicable to all hazardous waste combustors.

XV. How Did EPA Determine Compliance Times for this Proposed Rule?

    Section 112 of the CAA specifies the dates by which affected 
sources must comply with the emission standards. New or reconstructed 
units must be in compliance with the proposed rule immediately upon 
startup or [DATE THE FINAL RULE IS PUBLISHED IN THE Federal Register], 
whichever is later. A new or reconstructed unit for purposes of 
complying with this proposed rule is one that begins construction after 
April 20, 2004.\210\
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    \210\ Please note that a new or reconstructed unit for purposes 
of complying with the Interim Standards applicable to incinerators, 
cement kilns, and lightweight aggregate kilns is a unit that began 
operation after September 30, 1999.
---------------------------------------------------------------------------

    Existing sources are allowed up to three years to comply with the 
final rule. See proposed Sec.  63.1206(a)(1)(ii) and (a)(2). This is 
the maximum period allowed by the CAA. We believe that three years for 
compliance is necessary to allow adequate time to design, install, and 
test control systems that will be retrofitted onto existing units.

XVI. How Did EPA Determine the Required Records and Reports for the 
Proposed Rule?

    We propose notification, reporting, and recordkeeping requirements 
for solid fuel-fired boilers, liquid fuel-fired boilers and 
hydrochloric acid production furnaces that are identical to those 
already in place at Sec. Sec.  63.1210 and 63.1211 and applicable to 
incinerators, cement kilns, and lightweight aggregate kilns. Please 
note, however, that we are proposing a new requirement applicable to 
all hazardous waste combustors that would require you to submit a 
Notification of Intent to Comply and a Compliance Progress Report.

A. Summary of Requirements Currently Applicable to Incinerators, Cement 
Kilns, and Lightweight Aggregate Kilns and That Would Be Applicable to 
Boilers and Hydrochloric Acid Production Furnaces

    Owners and operators of solid fuel-fired boilers, liquid fuel-fired 
boilers, and hydrochloric acid production furnaces would be required to 
submit the following notifications to the Administrator in addition to 
those required by the NESHAP General Provisions, subpart A of 40 CFR 
part 63: (1) Notification of changes in design, operation, or 
maintenance (Sec.  63.1206(b)(5)(i)); (2) notification of performance 
test and continuous monitoring system evaluation, including the 
performance test plan and continuous monitoring system performance 
evaluation plan (Sec. Sec.  63.1207(e)); and (3) notification of 
compliance, including results of performance tests and continuous 
monitoring system evaluations (Sec. Sec.  63.1210(b), 63.1207(j); 
63.1207(k), and 63.1207(l)). You would also be required to submit 
notifications to the Administrator if you request or elect to comply 
with various alternative requirements. Those notifications are listed 
at Sec.  63.1210(a)(2).
    Owners and operators of solid fuel-fired boilers, liquid fuel-fired 
boilers, and hydrochloric acid production furnaces would be required to 
submit the following reports to the Administrator in addition to those 
required by the NESHAP General Provisions, subpart A of 40 CFR part 63: 
(1) Startup, shutdown, and malfunction plan (if electing to comply with 
Sec.  63.1206(c)(2)(ii)(B)); (2) excessive exceedances report (Sec.  
63.1206(c)(3)(vi)); and (3) emergency safety vent opening reports 
(Sec.  63.1206(c)(4)(iv)).
    Owners and operators of solid fuel-fired boilers, liquid fuel-fired 
boilers, and hydrochloric acid production furnaces would be required to 
keep records documenting compliance with the requirements of Subpart 
EEE. Recordkeeping requirements are prescribed in Sec.  63.1211(b), and 
include requirements under the NESHAP General Provisions, subpart A of 
40 CFR part 63.

B. Why Is EPA Proposing Notification of Intent to Comply and Compliance 
Progress Report Requirements?

1. What Is the Notification of Intent to Comply?
    In the June 1998 ``fast track'' rule (63 FR 33782), we required 
that sources subject to the Phase I subpart EEE standards complete a 
Notification of

[[Page 21314]]

Intent to Comply (NIC) no later than October 2, 2000 and conduct a NIC 
public meeting no later than July 31, 2000. The NIC and its associated 
public meeting served four primary purposes during the early 
implementation and compliance phases of the Phase I subpart EEE 
requirements which we believe were of benefit to regulators, sources 
and the public alike.
    First, the NIC served as a compliance planning tool for Phase I 
sources because it required you to develop an outline of the key 
activities that needed to be completed in order to meet the subpart EEE 
standards by the compliance date. It also required that you include the 
estimated dates for each of those key activities. Because the NIC was 
required to be completed within the first year of implementing the 
Phase I requirements, it also may have had the added and important 
benefit of encouraging sources to reduce their HAP emissions early. By 
focusing a source's attention on the means by which it would achieve 
compliance well before the actual compliance date, the NIC may have 
prompted some sources to upgrade their combustion design and operations 
earlier, thereby yielding an early reduction in HAP emissions. The NIC 
also may have prompted earlier waste minimization efforts for the same 
reason.
    Second, the NIC also served as a planning tool for regulatory 
authorities. Based on the information provided in the NIC, regulators 
could determine what activities were likely to occur and when over the 
course of the three-year compliance period. For example, they could 
estimate how many sources needed to modify their combustion units and 
existing RCRA permits prior to performance testing, how many sources 
intended to stop burning hazardous waste, and how many sources intended 
to apply for the comparable fuels exclusion. Using this information, 
regulators could plan how to most efficiently allocate their resources 
in response to the forthcoming compliance activities of the sources.
    Third, the NIC promoted early public involvement by fostering an 
open dialogue between sources and the public regarding compliance 
strategies for meeting the Phase I subpart EEE standards. Experience 
has shown that members of the public are interested in being kept 
adequately informed of and having input into the compliance and 
permitting activities of hazardous waste combustion facilities. The NIC 
and its associated public meeting provided an opportunity for the 
public to share their views, thereby allowing the source to develop a 
final compliance strategy that met the goals of both the source and the 
surrounding community.
    Fourth, the public involvement aspect of the NIC also offset any 
public participation opportunities that may have been ``lost'' if 
sources chose to take advantage of the RCRA streamlined permit 
modification process. Many Phase I sources had to modify their 
combustion systems' design and/or operations in order to comply with 
the MACT standards. Sources that were already operating under RCRA 
combustion permits needed to first modify those permits before 
initiating any MACT compliance related changes. Normally, a Class 2 or 
3 modification would be necessary to incorporate into a RCRA permit the 
types of changes we expected would be necessary for sources complying 
with Phase I standards. Given that Class 2 and 3 modifications could 
have consumed a year or more of a source's three-year subpart EEE 
compliance period, we developed a streamlined permit modification 
process solely for the purpose of implementing subpart EEE upgrades. 
Under the streamlined process, you could request a Class 1 modification 
with prior Agency approval to address and incorporate any necessary 
MACT upgrades into your RCRA permit. To be eligible to use the 
streamlined permit modification, however, you first must have complied 
with the NIC requirements, including those related to public 
involvement.
2. What Happened to the NIC Provisions?
    We promulgated the NIC on June 19, 1998 (63 FR 33782) along with 
several other requirements related to the Phase I NESHAP. On May 14, 
2001, we removed the NIC and two other provisions from the federal 
regulations in response to a court mandate to vacate. See 66 FR 24270. 
In Chemical Manufacturers Ass'n v EPA, 217 F. 3d 861 (D.C. Cir. 2000), 
the court vacated three provisions of the Phase I rule: the Early 
Cessation requirement, the NIC and the Compliance Progress Report.\211\ 
While the panel majority held that we possessed the legal authority to 
impose an Early Cessation requirement, the panel also held that we had 
claimed the authority to do so without making a showing of a health and 
environmental benefit (such as reduced HAP emissions or less hazardous 
waste generated) and that this was an impermissible statutory 
interpretation. See 217 F. 3d at 865-67. The panel majority further 
held that because it could not determine whether we would have 
promulgated the NIC and Progress Report requirements absent the Early 
Cessation provision, both the NIC and Progress Report requirements 
should be vacated as well. However, the panel did agree to issue a stay 
of its mandate for a long enough period of time to allow sources to 
submit their NICs so that they would be eligible for the RCRA 
streamlined permit modification.
---------------------------------------------------------------------------

    \211\ Under the Early Cessation provision, we required sources 
that did not intend to comply with the Phase I standards to stop 
burning hazardous waste within two years of the effective date of 
the Phase I rule. Under the Compliance Progress Report provision, we 
required sources to report to their regulatory agencies the status 
of their progress toward compliance with the standards.
---------------------------------------------------------------------------

    As discussed above, the NIC was intended to serve as a compliance 
planning and communication tool. We did not intend the NIC to serve as 
the basis for requiring a source to cease burning hazardous waste. 
However, as a planning and communication tool we expected sources that 
did not intend to comply with the standards to state this in their NIC 
and include a schedule of activities that the source would need to 
complete in order to stop burning hazardous waste within the two-year 
Early Cessation time frame. We believe that the court recognized this 
interpretation as our original intent in their agreement to stay their 
issuance of the mandate until after sources had submitted their final 
NICs on October 1, 2000. By allowing the Phase I sources to complete 
the NIC process, the court provided sources with the opportunity to 
effectively plan their compliance strategies and take advantage of the 
RCRA streamlined permit modification. It also provided the public with 
the opportunity for a level of participation that they may not have had 
otherwise.
3. Why Is EPA Proposing To Re-Institute the NIC for Phase I Sources?
    As stated above, we believe that the NIC was a valuable planning 
and communication tool for sources, regulators, and the public during 
the early implementation and compliance stages of the 1999 Phase I 
subpart EEE requirements. The NIC also provided an additional benefit 
to sources upgrading their combustion systems by compensating for any 
``lost'' public participation opportunities when using the RCRA 
streamlined permit modification process. As discussed in Part One, I. B 
and D, we are proposing in today's notice to supplant the existing 
Phase I standards with final Replacement standards. We anticipate that 
a significant number of Phase I sources may need to conduct additional 
upgrades, or in some cases upgrade for the first time, to comply with 
the Replacements standards. See

[[Page 21315]]

Sec. Sec.  63.1219, 63.1220, and 63.1221. Re-instituting the NIC for 
these sources could provide the same planning and communication 
benefits during the initial Replacement standards compliance period 
that it did for the original Phase I standards.
    Specifically, we expect that by focusing attention early on the 
necessary tasks and strategies for achieving compliance, Phase I 
sources will be in a better position to meet the Replacement standards 
by the compliance date. Regulators will gain insight from the 
information provided in the NIC to effectively allocate their resources 
to accommodate future regulatory activities. And, the NIC will provide 
the public with the opportunity and mechanism to keep abreast of any 
significant changes an existing source might need to make as a result 
of the Replacement standards. We do not believe that the same planning 
and communication opportunities gained from completing the NIC process 
are available from other portions of the air regulatory program. For 
example, although the public will be notified of a source's obligation 
to comply with the Replacement standards during the reopening or 
renewal of the source's title V, this notification, in most cases, will 
not occur as early in the three-year subpart EEE compliance period, nor 
is it likely to include the specific information regarding the source's 
compliance strategy.\212\
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    \212\ If a major title V source has a remaining permit term of 
three or more years on the date the Replacement standards are 
promulgated, the title V permitting authority must complete a 
reopening of the source's title V permit to incorporate the 
requirements of these standards not later than 18 months after 
promulgation. Major sources having remaining permit terms of less 
than three years on the date the Replacement standards are 
promulgated may wait until permit renewal to incorporate the new 
standards. Area sources with title V permits likewise may wait until 
permit renewal. Permitting authorities must follow the same public 
notice procedures for title V permit reopenings and renewals as is 
required for initial permit issuance under title V, including 
providing public notice of the action, providing a public comment 
period of at least 30 days, and providing an opportunity for a 
public hearing. See 40 CFR 70.7 and 71.7.
---------------------------------------------------------------------------

    In addition, while we believe that there will be fewer Phase I 
sources in the position of having RCRA combustion permit conditions 
after demonstrating compliance with the Interim standards, for those 
that do and wish to use the streamlined permit modification process to 
allow any necessary Replacement standards upgrades, a second NIC would 
provide the same public participation benefits as did the first 
NIC.\213\ 40 CFR 270.42(j) currently allows a source to use the RCRA 
streamlined modification process provided that the source first 
complied with the NIC requirements that were in place prior to October 
11, 2000. Since many sources complied with those NIC requirements in 
1999 and 2000, the existing regulatory language would allow those same 
sources to further modify their RCRA permits for Replacement standards 
upgrades. The regulatory language does not make any distinction 
regarding when the upgrades are to take place in relation to when the 
NIC requirements were to have been fulfilled. We do not believe that it 
is appropriate for a source to rely on previous informational and 
public participation activities carried out to comply with the earlier 
NIC requirements and emission standards to address upgrades occurring 
years later in response to a different set of standards any more than 
it would be appropriate to allow the public participation activities of 
a previous RCRA modification to suffice for a later modification. By 
requiring sources that choose to use the RCRA streamlined permit 
modification process for Replacement standards upgrades to first 
complete a NIC, including its associated public meeting, that 
specifically addresses those Replacement standards upgrades, the 
community will be kept better informed of additional changes to the 
combustion system and the impact on the RCRA permit.
---------------------------------------------------------------------------

    \213\ Once a source conducts its CPT and submits an Notification 
of compliance documenting compliance with the Subpart EEE standards, 
the source may request that its RCRA permit be modified to remove 
any duplicative limits or conditions. Only those risk-based 
provisions that are more stringent than the MACT requirements as 
specified in the Notification of compliance or that address other 
emission hazards will remain in the RCRA permit. We expect that many 
sources will document compliance with the Phase I Interim standards 
between 2003 and 2004 and will request the removal of any 
duplicative, less stringent provisions from their RCRA permits 
shortly thereafter.
---------------------------------------------------------------------------

4. Why Is EPA Proposing To Require the NIC for Phase II Sources?
    We believe that the NIC would provide the same benefits with 
respect to communication and compliance strategy planning for the Phase 
II sources that it has for Phase I sources. In addition, without 
completing the NIC process, Phase II sources will not be eligible to 
take advantage of the RCRA streamlined permit modification when 
upgrading their combustion systems. We are proposing that Phase II 
sources comply with the same NIC requirements as their Phase I 
counterparts.
5. How Will the NIC Process Work?
    We are proposing to apply a similar NIC process to that which we 
promulgated in the June 19, 1998 ``fast track'' rule (63 FR 33782). The 
following is a general description of that process. Within nine months 
of the promulgation of the final Phase I Replacement standards and 
Phase II standards, you would develop and make publicly available a 
draft NIC. The draft NIC would contain general information such as 
whether you are a major or an area source and what waste minimization, 
emission control techniques, and emission monitoring techniques you 
might be considering. At the same time, you would also provide a notice 
to the public of at least one informal NIC public meeting. Within ten 
months, you would hold this public meeting to discuss the activities 
you described in the draft NIC for achieving compliance with the 
subpart EEE standards. The meeting provides an opportunity for a mutual 
understanding between you and the public regarding compliance options, 
including consideration of both technical (e.g., equipment changes to 
upgrade air pollution control devices) and operational (e.g., process 
changes to minimize waste generation) alternatives. We expect the 
exchange between you and the community at the meeting to be similar to 
that which would occur at RCRA pre-application meetings. That is, we 
intend for the meeting to provide an open, flexible and informal 
occasion for you and the public to discuss various aspects of your 
compliance strategy, provide an opportunity for sharing ideas and 
provide an opportunity for building a framework for a solid and 
positive working relationship. Lastly, you would submit a final NIC to 
your regulatory authority that would include the information provided 
in the draft NIC (revised as necessary after the public meeting) as 
well as a summary of the public meeting. This final NIC would be 
submitted to your regulatory authority within one year of the 
promulgation of the final Phase I Replacement standards and Phase II 
standards.
    In summary, we believe that the NIC would provide important 
planning and communication opportunities for both Phase I and Phase II 
sources. It also would allow all Phase I, as needed, and Phase II 
sources to take advantage of the RCRA streamlined permit modification 
procedure. Thus, we are proposing NIC requirements for both Phase I and 
Phase II sources.

[[Page 21316]]

6. What Is the Compliance Progress Report?
    In addition to the NIC, we also promulgated Compliance Progress 
Report requirements in the 1998 ``fast track'' rule. See 63 FR 33782. 
The purpose of the Progress Report was to help regulatory agencies 
determine if sources were making reasonable headway in their efforts to 
come into compliance. The Progress Report was required to be submitted 
at the midpoint of the three-year compliance period and contain 
information that essentially built on the information you previously 
provided in the NIC. For example, if you indicated in the NIC that you 
needed to make specific physical modifications to your combustion 
system in order to comply with the standards, you would be expected to 
describe your progress in making those modifications in your Compliance 
Progress Report. Although the Progress Report was primarily intended as 
a tool for the regulatory agencies, we believe it also may have been 
beneficial to sources as well. For example, the Progress Report could 
have been used by sources as a mechanism to review and make any 
necessary changes to their original strategy for achieving compliance.
    As discussed in the previous section, the Court vacated the early 
cessation, NIC and Compliance Progress Report provisions of the Phase I 
rule in Chemical Manufacturers Ass'n v EPA, 217 F. 3d 861 (D.C. Cir. 
2000). Although the Court's primary focus was the early cessation 
provision, it also vacated the Progress Report requirements because it 
could not determine whether we would have promulgated those 
requirements absent the early cessation provision.
7. Why Is EPA Requesting Comment on Requiring the Compliance Progress 
Report for Phase I and Phase II Sources?
    We believe that the Progress Report would be a useful tool for both 
regulators and sources in measuring progress toward achieving 
compliance with the Subpart EEE standards and determining if any 
revisions to a source's compliance strategy are necessary. Unlike the 
NIC, however, we do not have practical experience with the application 
of the Compliance Progress Report, because the Court vacated its 
requirements prior to their implementation. As a result, we are 
requesting comment on whether or not the Compliance Progress Report 
should be required for Phase I or Phase II sources.
8. How Would the Compliance Progress Report Requirement Work?
    The Compliance Progress Report requirements would be similar to 
those promulgated for Phase I sources in the June 19, 1998 ``fast 
track'' rule (63 FR 33782). Within two years of the promulgation of the 
final standards, you would develop and submit to your regulatory 
authority a Compliance Progress Report. The Report would include 
information which demonstrates your progress toward compliance. This 
could include, for example, completed engineering designs for any 
physical modifications to the combustion unit that are needed to comply 
with the standards; copies of construction applications; and binding 
contractual commitments to purchase, fabricate, and install any 
necessary equipment, devices, and ancillary structures. In addition, 
you would be expected to include a detailed schedule that lists the 
dates for all remaining key activities and projects that will bring you 
into compliance with the standards. For example, you would include bid 
and award dates for construction contracts, milestones for 
groundbreaking, and dates for the approval of permits and licenses. We 
would also expect you to include in your report any updates or changes 
to the information you previously provided in your NIC, including if 
you have changed your compliance plan based on engineering studies or 
evaluations that you have conducted since your NIC submittal.\214\ 
Sources that intend to cease burning hazardous waste prior to or on the 
compliance date would still be expected to submit a report describing 
key activities and projected dates for initiating RCRA closure and 
discontinuing hazardous waste activities at the combustion unit.
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    \214\ For example, if you reported in your NIC that you intended 
to upgrade your existing unit, but later determined that it was more 
appropriate to replace the unit with a new unit, we would expect you 
to inform your regulatory agency of this change in your compliance 
plan in your Compliance Progress Report.
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XVII. What Are the Title V and RCRA Permitting Requirements for Phase I 
and Phase II Sources?

    In today's notice of proposed rulemaking, we are maintaining the 
same general approach we took in the 1999 rule with respect to title V 
and RCRA permitting requirements and the Phase I sources. We feel that 
this approach, to place the MACT air emissions and related operating 
requirements in the title V permit and to continue to require RCRA 
permits for all other aspects of the combustion unit and the facility 
that are governed by RCRA, is still the most appropriate method to meet 
our obligations under both statutes. In 1999, our goal in developing a 
permitting scheme to accommodate both statutes with respect to air 
emission limitations and standards, was to avoid duplication to the 
extent practicable and to streamline requirements. We remain committed 
to that goal, as we revise and refine the permitting approach we 
finalized in 1999.

A. What Is the General Approach To Permitting Hazardous Waste 
Combustion Sources?

    In the September 1999 rule, we finalized a permitting approach that 
places the MACT air emissions and related operating requirements in the 
title V permit and retains all other RCRA related requirements (e.g., 
corrective action, general facility standards, other combustor specific 
concerns such as material handling, risk-based emission limits and 
operating requirements, and other hazardous waste management units) in 
the RCRA permit. See 64 FR 52828, 52833-52834 (September 30, 2000). 
Under this approach, sources comply with their RCRA emission limits and 
operating requirements until they demonstrate compliance with the MACT 
standards by conducting a comprehensive performance test and submitting 
a Notification of Compliance (NOC) to the Administrator (or authorized 
State) that documents compliance.\215\ Upon documenting compliance 
through the NOC, sources may begin the transition from RCRA permitting 
to title V permitting.
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    \215\ There is no change to our decision to subject Phase I area 
sources to the same MACT standards and title V permitting 
requirements as the major sources. For Phase II sources, area 
sources are required to meet the same MACT standards as major 
sources, but only for: dioxin/furan, mercury, carbon monoxide/
hydrocarbons, and destruction and removal efficiency. See Part Two, 
Section I.A. for more information on regulation of area sources. 
Therefore, Phase II area sources will be required to obtain a title 
V permit only for those MACT standards as discussed later in 
Paragraph C.4. of this section.
---------------------------------------------------------------------------

    We believe that this approach still makes the most sense in terms 
of providing flexibility and minimizing duplication between the two 
permitting programs, while ensuring that there is no break in 
regulatory coverage. It is also appropriate given where sources will be 
in the transition process of complying with the MACT Interim Standards 
upon promulgation of the Phase I Replacement standards and the Phase II 
standards. The majority of Phase I sources will have initiated a

[[Page 21317]]

significant modification of their title V permits to include the 
operating requirements of their NOC and a modification of their RCRA 
permits to remove duplicative conditions. By this time, permitting 
authorities and sources are familiar with the current permitting 
approach and have worked through many issues to make compliance with 
the Interim Standards and the ensuing transition successful. We feel 
that permitting authorities and sources would prefer to draw upon their 
experiences and utilize the expertise they have developed, rather than 
exploring ways to implement a new permitting scheme. Therefore, we are 
retaining the same general approach to permitting for Phase I sources 
and are proposing to apply this same general approach to Phase II 
sources in today's Notice of proposed rulemaking: to place the MACT 
emission standards only in the CAA regulation at 40 CFR part 63 subpart 
EEE, and rely on implementation through the air program and operating 
permit programs developed under title V.
1. What Is the Authority for the Proposals Discussed in This Section?
    EPA is issuing these proposals to modify RCRA permits under the 
authority of sections 1006(b), 2002, 3004, 3005 and 7004(b) of RCRA. 
With regard to the regulatory framework that would result from today's 
proposal, we are proposing to eliminate the existing RCRA stack 
emissions national standards for hazardous air pollutants for hazardous 
waste combustors. That is, after submittal of the NOC 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 
emission standards under the authority of section 3004(a) and (q) of 
RCRA, which calls for EPA to promulgate standards ``as may be necessary 
to protect human health and the environment.'' We believe that the 
proposed MACT standards are generally protective of human health and 
the environment, and that separate RCRA emission standards are not 
needed to protect human health and the environment. Refer to Part Four, 
Section IX. How Does the Proposed Rule Meet the RCRA Protectiveness 
Mandate? for a discussion on this topic.
    In addition, 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.
    We are not proposing, however, that RCRA permit conditions to 
control emissions from these sources will never be necessary, only that 
the national RCRA standards appear to be unnecessary. Under the 
authority of RCRA's ``omnibus'' clause section 3005(c)(3); see 40 CFR 
270.32(b)(2)), RCRA permit writers may impose additional terms and 
conditions on a site-specific basis as may be necessary to protect 
human health and the environment. Thus, if MACT standards are not 
protective of human health and the environment in an individual 
instance, RCRA permit writers will establish permit limits that are 
protective.
    In RCRA, Congress gave EPA broad authority to provide for public 
participation in the RCRA permitting process. Section 7004(b) of RCRA 
requires EPA to provide for, encourage, and assist public participation 
in the development, revision, implementation, and enforcement of any 
regulation, guideline, information, or program under the Act.
2. Is EPA Proposing a Different Permitting Approach for New Sources?
    As discussed above, we are maintaining the same general permitting 
approach as before. However, we are proposing to eliminate the 
unintended result of the previous regulatory construct, which caused 
new sources to initially be subject to the RCRA air emission and 
operating requirements. In particular, we want to specify that any 
hazardous waste burning incinerators, cement kilns, lightweight 
aggregate kilns, boilers, and hydrochloric acid production furnaces 
newly entering the RCRA permitting process (e.g., sources that are 
seeking an initial RCRA permit or permit modification to include a new 
hazardous waste combustion unit) after promulgation of the Phase I 
Replacement standards and Phase II standards are not subject to certain 
specified RCRA permit requirements or performance standards. The 
approach we are proposing today is similar to the one we proposed in 
the July 3, 2001, proposed amendment rule (see 66 FR 35146), but was 
not finalized. The amendment was not finalized due to several 
unresolved issues and thus, it was agreed (during litigation settlement 
discussions), that we would revisit and address the issues in the Phase 
I Replacement standards and Phase II standards rulemaking.
    a. Why Is EPA Proposing a Different Permitting Approach for New 
Sources? In the September 1999 rule, we had amended language in 40 CFR 
264.340, 265.340, 266.100, 270.19, 270.22, 270.62, and 270.66 to 
accommodate the permit transition from RCRA to the CAA. To summarize, 
the amended language in these sections says that once a source 
demonstrates compliance with the standards in 40 CFR part 63 subpart 
EEE, the requirements in specified part 264, 265, 266, and part 270 
sections would no longer apply. However, the amended language neglected 
to specifically address if, how, or when new sources would make the 
transition from RCRA permitting requirements to CAA MACT requirements.
    As we discussed in the preamble to the July 3, 2001, proposed 
amendments, under RCRA, new sources must obtain a permit or a permit 
modification before they may start construction of a new source/unit. 
The way the current part 270 language reads, new sources subject to the 
1999 rule and the Interim Standards rule are not able to demonstrate 
compliance with the part 63 standards until after a RCRA permit is 
issued, the source is built, and they conduct performance testing. This 
means they would have to submit a trial burn plan with their RCRA 
permit application and also submit suggested conditions for the various 
phases of operation--start-up/shake-down, trial burn, and post-trial 
burn. Likewise, RCRA permitted facilities that are adding a new 
combustion source would have to provide the same information with their 
permit modification request. Whether the source is new or adding a new 
combustion source, the permit writer would have to review this 
information and write conditions into the RCRA permit governing all 
phases of combustor operations. This expenditure of resources, on the 
part of the source and the permitting agency, is unnecessary given that 
the conditions will become inactive or be removed from the RCRA permit 
upon compliance with the MACT standards. For new sources, compliance 
with the MACT standards is upon start-up. Therefore, today we are 
proposing that new sources (whether a new source or a new source at an 
existing permitted source) who will be subject to the Phase I 
Replacement standards and Phase II standards upon start-up, not follow 
the RCRA permitting process for establishing combustor emissions and

[[Page 21318]]

operating requirements (i.e., submission of a trial burn plan with the 
RCRA permit application, submission of suggested conditions for the 
various phases of operation--start-up/shake-down, trial burn, and post-
trial burn, and ultimately obtaining a permit with operating and 
emission standards).
    b. How Is EPA Proposing to Change the Current Requirements for New 
Sources? In the July 3, 2001 proposal, we developed regulatory language 
to clarify our intent not to require new sources to obtain a RCRA 
permit with respect to combustor operations and emissions. In response 
to that proposal, we received comments from the Sierra Club expressing 
concerns that the increased opportunities for public participation 
established in the RCRA Expanded Public Participation Rule (60 FR 
63417, December 11, 1995) would be lost. This rule involves communities 
earlier in the permitting process, provides more opportunities for 
participation, expands public access to information, and offers 
guidance on how facilities can improve public participation. In a 
follow-up discussion with the Sierra Club, they specifically expressed 
interest in being able to influence decisions on the construction of 
hazardous waste combustors. Upon consideration, we agree with the 
Sierra Club that in our previous effort to streamline the RCRA 
permitting process for new sources, we did not fully consider that 
important opportunities for public participation may be lost. Although 
we still believe that new sources, whether a new source or an existing 
source adding a new source, should not be required to follow the RCRA 
permitting process, we also believe that the Sierra Club's concerns 
have merit. It makes sense to afford the public the same (or as close 
as possible) public participation opportunities for new units under the 
HWC MACT/CAA framework that they had under the RCRA regulations. 
Therefore we are modifying our earlier proposal as discussed in the 
paragraphs below, to consider several options that will attempt to 
address these concerns, as well as provide a means to improve the 
existing regulatory requirements for new sources.
    The RCRA Expanded Public Participation Rule implemented four new 
requirements for facilities and permitting agencies that enable 
communities to become more active participants throughout the 
permitting process. They are: (1) Permit applicants must hold an 
informal public meeting before applying for a permit; (2) permitting 
agencies must announce the submission of a permit application which 
will tell community members where they can view the application while 
the agency reviews it; (3) permitting agencies may require a facility 
to set up an information repository at any point during the permitting 
process if warranted; and (4) permitting agencies must notify the 
public prior to a trial (or test) burn. Consequently, we will focus on 
each of these and propose mechanisms that mirror or fulfill the RCRA 
public participation requirements.
    We stated earlier in this section that under RCRA, new sources must 
obtain a permit (or a permit modification at an existing source) before 
they may start construction of a new source. This holds true regardless 
of whether we finalize an approach that does not require new sources to 
obtain a RCRA permit that contains the combustor operating and 
emissions standards (i.e., a RCRA permit will still be required to 
address all other activities at the facility including corrective 
action, general facility standards, other combustor specific concerns 
such as material handling, risk-based emission limits and operating 
requirements, and other hazardous waste management units). So, in 
applying for a RCRA permit, new hazardous waste facilities/sources will 
still be required to meet the public participation requirements. 
However, the problem arises if new sources are not required to provide 
information relative to the combustor (i.e., sources were formerly, at 
this point in the process, required to submit a trial burn plan), but 
only for the other proposed hazardous waste management activities at 
the source. Thus, the source would not be required to discuss the 
proposed combustor-specific operations and emissions at the informal 
public meeting, nor would the permit application that is made available 
to the public to review, contain information regarding the combustor 
operations or emissions.
    In an effort to provide an opportunity for public participation 
equivalent to RCRA, we believe that the Notification of Intent to 
Comply (NIC) requirements, as proposed in Part Two, Section XVI.B., 
serve in place of the first two RCRA public participation requirements. 
The primary functions of the NIC are to serve as a compliance planning 
tool and to promote early public involvement in the permitting process. 
In terms of compliance planning, the draft NIC must contain general 
information including the waste minimization, emission control, and 
emission monitoring techniques that are being considered and how the 
source intends to comply with the emission standards. With regard to 
early public involvement, a draft of the NIC must be made available to 
the public for review within 9 months of the effective date of the 
final Replacement Standards and Phase II Standards rule. One month 
later, the source must hold an informal public meeting to discuss the 
activities described in the NIC. The NIC requirements apply to new 
sources as well (see Sec.  63.1212(b)(1) in today's Notice), but the 
timing will vary according to the date a new source begins burning 
hazardous waste. For example, if a new source begins burning 3 months 
after the rule's effective date, then it will have only 6 months before 
it must prepare and make a draft NIC available for public review.\216\ 
More significantly, according to 40 CFR 63.1212(b)(2), as proposed in 
today's Notice, new sources that are to begin burning more than 9 
months after the effective date of the final rule will be required to 
meet all of the NIC and Compliance progress report requirements in 
Sec. Sec.  63.1210(b) and (c), 63.1211(c), and 63.1212(a) prior to 
burning hazardous waste.
---------------------------------------------------------------------------

    \216\ Note that new sources must have prepared and included 
their documentation of compliance in the operating record upon 
start-up. New sources then have 6 months from the date of start-up 
to begin their comprehensive performance test.
---------------------------------------------------------------------------

    We feel that the NIC requirements are commensurate with the public 
participation requirements to hold an informal public meeting to inform 
the community of the proposed combustor operations and to make the 
compliance information available for public review and comment. On the 
other hand, we also recognize that there are a few gaps. For instance, 
the NIC requirements are not associated with a permit action and the 
regulatory agency is not required to be present at the NIC public 
meeting. We would, however, expect the source to consider any comments 
raised during the NIC process as it develops its final compliance 
strategy and final NIC.\217\ Also, if a new source begins burning after 
the effective date of today's rule, but prior to 9 months after the 
effective date, the NIC is not required to be made available for public 
review before a new source begins burning. In other words, the public 
is not provided information relative to the combustor's operations, 
emissions, and compliance schedule prior to it beginning operations. 
Given these gaps, we are proposing a scenario in which the NIC 
requirements for new sources under MACT, could be crafted

[[Page 21319]]

to achieve a comparable level of public participation as under RCRA.
---------------------------------------------------------------------------

    \217\ If necessary, concerns raised regarding the regulation of 
the combustor can be addressed through application of RCRA's omnibus 
provision (RCRA section 3005(c)(3)).
---------------------------------------------------------------------------

    We are proposing to require that all new sources prepare a draft 
NIC and make it available to the public at the same time as their RCRA 
pre-application meeting notice. We also propose that new sources submit 
their comprehensive performance test plan at this time. By submitting 
the NIC and CPT plan together, the public would be provided with 
compliance-related information relevant to the combustor as well as the 
proposed combustor operations and emissions (i.e., the public is 
provided testing information through the CPT that they would have 
received via the trial burn plan). Lastly, as part of this option we 
propose that the NIC public meeting coincide with the informal public 
meeting for the RCRA permit. By holding a simultaneous meeting, the 
public is given the opportunity to inquire and comment on both the 
source's proposed activities and the combustor's proposed operations 
with regulatory officials from both the Air and RCRA programs present. 
We request comment on this discussion.\218\
    With respect to the information repository regulations at 40 CFR 
124.33, the purpose of the information repository is to make 
information (i.e., documents, reports, data, and information deemed 
necessary) available to the public during the permit issuance process 
and during the life of a permit. While the Title V permit procedures 
specify that information relevant to the permitting decision be made 
available to the public,\219\ this information would not be accessible 
prior to construction or operation of the combustor. Under RCRA, the 
information repository would be established some time after submission 
of the permit application, but before construction and operation of the 
combustor. Even though an information repository is not a required 
component of the RCRA permit process, the regulations provide a 
permitting agency with the discretion to evaluate the need for and 
require a source to establish and maintain one. Therefore, so that the 
public is afforded the same opportunities to view and copy information 
such as the NIC, test plans, draft Title V permit and application, 
reports and so forth under MACT, we are considering two options. We 
could include a provision similar to Sec.  124.33 in the NIC 
regulations for new sources. It would allow a regulatory agency, on a 
case-by-case basis, to require a source to establish an information 
repository specific to the combustor. We believe the NIC regulations 
are a suitable location to place such a provision, since the NIC is the 
first opportunity for the public to discuss the combustor operations 
and emissions. Alternatively, rather than incorporate provisions for an 
information repository in the NIC regulations, the applicability 
language in Sec.  124.33 could be amended to include new combustion 
sources that will comply with Part 63, subpart EEE upon start-up. We 
request comment on this discussion.
---------------------------------------------------------------------------

    \218\ Since the public participation requirements of 40 CFR 
124.31 and 124.32 only apply to initial RCRA permits and renewals 
with significant changes, a corresponding regulatory amendment would 
need to be made to the applicability paragraphs to include 
modifications to RCRA permits only for new combustion sources that 
will comply with Part 63, subpart EEE upon start-up. Also, 
63.1212(b) would need to be amended to reference Sec. Sec.  124.31 
and 124.32.
    \219\ 40 CFR Sec.  70.7(h)(2) requires that information 
including the draft Title V permit, the application, all relevant 
supporting materials, and other materials available to the 
permitting authority that are relevant to the permit decision, be 
made available to interested persons.
---------------------------------------------------------------------------

    The last RCRA public participation requirement requires the 
permitting agency to notify the public prior to a trial burn or test 
burn at a combustion facility. If new sources are not required to 
follow the RCRA permitting process with respect to combustor emissions 
and operations, they also would not be required to submit a trial burn 
plan with their permit application or conduct a trial burn. However, 
under MACT, new (and existing) combustion sources are required to 
submit performance test and continuous monitoring system (CMS) 
performance evaluation test plans for approval. The MACT performance 
test serves the same purpose as the RCRA trial burn test: To 
demonstrate compliance with the relevant emission standards and to 
collect data to determine at what levels the corresponding operating 
conditions should be set. Similar, but not identical to the RCRA 
requirements at 40 CFR 270.62 and 270.66 requiring the permitting 
agency to notify the public prior to a trial/test burn, the MACT 
performance test regulations (see Sec.  63.1207(e)(2)), specify that a 
source must issue a public notice announcing the approval of the test 
plans and provide a location where the public may view them. Although 
the timing of the public notices are slightly different, the 
regulations both provide notice to the public about testing. Under 
RCRA, notice is given to the public prior (usually 30 days) to 
commencement of the trial burn, whereas under MACT, notice is given 
when the test plans are approved. The newly amended regulations of 
Sec.  63.1207(e)(2) proposed in this Notice, specify that sources must 
make the test plans available for review at least 60 days prior to 
commencement of the test and must provide the expected time period for 
commencing (and completing) the test. Thus, the public is informed of 
the test and provided estimates of test dates through public notice of 
the approved test plan.
    Thus far, the approach we have proposed is intended to ensure that 
the public will have the same opportunities for participation and 
access to information as they would if new sources continued to be 
subject to the RCRA permit process to include the combustor emission 
and operating requirements. By proposing that new sources not be 
required to obtain a RCRA permit with combustor emission and operating 
requirements, it provides for the smoothest and most practical 
transition from RCRA requirements to MACT requirements.\220\
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    \220\ This approach does not eliminate the possibility that some 
combustor-specific requirements may be retained in the RCRA permit 
such as: Risk-based conditions, compliance with an alternative MACT 
standard, compliance with startup, shutdown and malfunction events 
under RCRA rather than the CAA, etc. See section XVII, D.2. for a 
more complete discussion. Consequently, sources would be expected to 
include the applicable RCRA conditions in their RCRA permit 
application.
---------------------------------------------------------------------------

    Aside from the approach we have focused on, there are others that 
may be worthy of consideration. We can also look at the option of a 
transition point for new sources that would specify how far a new 
source would proceed down the RCRA permit path before it could 
``transition'' over to compliance with the MACT standards and CAA 
permitting. There are three additional options we can consider relative 
to a transition point: (1) After the RCRA Part B application is 
submitted; (2) after the RCRA permit is issued; and (3) after the 
source places its Documentation of Compliance (DOC) in the operating 
record.
    Beginning with the first option, each successive one moves in the 
direction toward the way new sources currently make the transition from 
RCRA to MACT and includes modifications to the RCRA information 
requirements. We envision each of these options to be a variation of 
the current RCRA permit process. Under the first option, the transition 
point would occur after the source submits its RCRA Part B application. 
The key to this option is that the source would be subject to the 
public participation requirements of 40 CFR 124.31 and 124.32, to hold 
an informal public meeting and to have the submission of the permit 
application noticed. However, new sources would

[[Page 21320]]

not be required to include the combustor's operation and emission 
information in the Part B application. Rather, the source would only be 
required to discuss the compliance-related activities related to the 
combustor as part of the informal public meeting. For the second 
option, the transition point would be after the permitting agency 
issues the RCRA permit. The source would not only discuss the 
combustor's compliance-related activities as part of the RCRA informal 
public meeting as in the first option, but it would also address the 
operations and emissions through development of a trial burn plan, or a 
CPT plan in lieu of the trial burn plan, or even a coordinated CPT/RCRA 
trial burn plan, if it is likely that the source will require some RCRA 
permit conditions (i.e., risk-based conditions). With this option, even 
though all activities pre-permit issuance must address the source and 
the combustor's operations and emissions, the approved permit would not 
contain the operating and emission requirements (with the exception of 
risk-based or alternative standards). For the third option, the 
transition point would be after the source places its DOC in the 
operating record, which indicates the source's compliance with the MACT 
standards. Basically, the source would proceed down the RCRA permit 
path as in option two by complying with the public participation 
requirements, submitting a trial burn plan/CPT plan/coordinated plan, 
suggesting conditions for the various phases of operation, and 
receiving a RCRA permit. However, in this option, the permit would need 
to address combustor operations and emissions to the extent that it 
would cover the construction and start-up/shakedown periods.
    With respect to the public participation requirements, all three 
options automatically factor in the first two RCRA public participation 
requirements (by virtue of where the transition would be made). 
However, we did not discuss how we would account for the remaining two 
public participation requirements. We believe that the information 
repository and the notification of a trial burn requirements can be 
addressed in the same manner as we discussed in our proposed approach. 
So, for these options, we would incorporate an appropriate requirement, 
either through the NIC regulations or the public participation 
regulations, that would allow for an information repository to be 
established. Regarding the notice of a trial burn, we believe that the 
notice of the performance test is equivalent.
    In summary, our proposed approach involves modifying the NIC 
provisions to include RCRA public participation requirements. The 
second group of options consider a range of transition points that are 
also worthy of consideration. We invite comment on this discussion.
3. What Are the Proposed Changes to the RCRA Permitting Requirements 
That Will Facilitate the Transition to MACT?
    To alleviate potential conflicts between the RCRA permit 
requirements and MACT, we are proposing an additional streamlined 
permit modification provision, requiring prior Agency approval, which 
would allow an existing RCRA permit to be better aligned with specific 
provisions contained in the Subpart EEE requirements. The intent of 
this provision is to reduce potential burdens associated with 
compliance with overlapping RCRA and MACT requirements, while still 
maintaining the overall integrity of the RCRA permit.
    a. How Will the Overlap During Performance Testing Be Addressed? 
When we finalized the performance test requirements and the changes to 
the RCRA permitting requirements in the September 30, 1999, rule, we 
did not consider how sources would conduct their performance tests 
while at the same time, maintain compliance with their RCRA permit 
requirements. For instance, during the performance test, a source will 
likely want to conduct testing at the edge of the operating envelope or 
the worst case for certain parameters to ensure operating flexibility. 
This could conflict with established operating and emissions limits 
required in the source's RCRA permit and consequently, prevent the 
source from optimizing its testing range.
    Currently, sources have three options that would allow them to 
resolve any potential conflicts between their performance test and 
their RCRA permit requirements. One option would be for a source to 
submit a RCRA Class 2 or 3 permit modification request to temporarily 
change or waive specific RCRA permit requirements during the MACT 
performance test (see Sec.  270.42, appendix I, L.5). Another option 
would be for a source to request approval for such changes through its 
RCRA trial burn plan or coordinated MACT / RCRA test plan (see Sec.  
270.42, appendix I, L.7.a. or d.). In this case, a source could include 
proposed test conditions in its plan to temporarily waive specific RCRA 
permit requirements during the test. The last option would be for a 
source to request a temporary authorization that would allow specific 
RCRA permit requirements to be waived for a period of 180 days (see 
Sec.  270.42(e)).
    We do not believe that any of the options discussed above provide 
an optimal solution to resolving conflicts between a source's 
performance test protocol and its RCRA permit operating and emissions 
limits. A Class 2 or 3 RCRA permit modification may not be an option 
for many sources due to the time typically involved in processing these 
requests. Sources that choose to modify their permits would need to do 
so well in advance of conducting their performance test to ensure that 
the modification would be processed in time to conduct the test on 
schedule. This may result in sources submitting modification requests 
prior to approval of their performance test plans. We believe that RCRA 
permit writers are unlikely to approve any modifications to RCRA permit 
requirements without the assurance that the source will be operating 
under an approved test plan. Resolving conflicts using a trial burn or 
coordinated test plan is not a viable option for a source that has 
already completed its trial burn/risk burn testing. Lastly, while a 
temporary authorization is relatively streamlined, it is meant to be 
used in unique cases affecting an individual facility. We believe that 
it is most logical and easily implemented to propose a modification 
that can be used consistently to remedy a common problem affecting an 
entire group of facilities with similar operations (e.g., hazardous 
waste burning combustors facing barriers to testing due to RCRA permit 
requirements). Therefore, in today's Notice, we are proposing to allow 
sources to waive specific RCRA permit operating and emissions limits 
during pretesting, initial, and subsequent performance testing through 
a new streamlined permit modification procedure.\221\
---------------------------------------------------------------------------

    \221\ For subsequent performance tests, we anticipate that this 
modificaiton would be useful for sources that may have risk-based or 
alternative requirements in their RCRA permits.
---------------------------------------------------------------------------

    We believe that a process for waiving specific RCRA permit 
requirements during performance testing is consistent with our 
objectives to streamline requirements and minimize conflicts between 
the RCRA and CAA programs without sacrificing the protections afforded 
by RCRA. Moreover, we view this new permit modification to be 
complementary to the provisions of Sec.  63.1207(h) for waiving 
operating parameter limits (OPLs) during

[[Page 21321]]

performance testing. In the February 14, 2002 final amendments rule, we 
reiterated that OPLs in the Documentation of Compliance (DOC) may be 
revised at any time to reflect testing parameters for the initial 
performance test prior to submission of the NOC and so, in effect, are 
automatically waived. Also, we revised the language in Sec.  
63.1207(h)(1) and (2) to not require that subsequent performance test 
plans be approved in order to waive OPLs, but rather that sources only 
record the emission test results of the pretesting.
    b. Are There Other Instances Where the New Streamlined Permit 
Modification Can Be Used? In addition to our efforts today to minimize 
overlapping permit requirements during performance testing, we are also 
proposing to allow the new streamlined permit modification to address 
other potential conflicts. In implementing the 1999 rule, it has become 
clear that there are several other instances when conflicts may arise 
where RCRA permit requirements overlap with MACT requirements. For 
example, the required averaging period for an operating parameter might 
be slightly different between MACT and the RCRA permit, requiring two 
different data acquisition schemes during the interim period between 
submittal of the Documentation of Compliance (DOC) and the final 
modification of the RCRA permit after receipt of the NOC. Or, if a RCRA 
permit requires periodic emissions testing, the specified test schedule 
in the permit might not be aligned with the required test schedule for 
MACT, causing a facility to perform duplicate testing instead of 
allowing a single coordinated RCRA/MACT test event. Conflicts in 
operating limitations, monitoring and recordkeeping requirements, and 
scheduling provisions can be especially prevalent during this interim 
period. Consequently, we believe the new streamlined permit 
modification procedure would be appropriate to address these probable 
overlaps.
    c. Why Is a New Streamlined Permit Modification Procedure Being 
Proposed? This new streamlined modification differs from the one we 
finalized in the June 1998 ``fast track'' rule (63 FR 33782). In 1998, 
we provided for a streamlined RCRA permit modification process whereby 
you could request a Class 1 modification with prior Agency approval to 
address and incorporate any necessary MACT upgrades into your RCRA 
permit (see 40 CFR 270.42, appendix I, L(9)). The streamlined permit 
modification provision, which was intended solely for the purpose of 
implementing physical or operating upgrades, allowed sources that were 
already operating under RCRA combustion permits to modify their 
combustion systems' design and/or operations in order to comply with 
the MACT standards without having to obtain a Class 2 or 3 RCRA permit 
modification. Thus, L(9) was not intended to account for overlapping 
requirements. Further, to be eligible to use L(9), you first must have 
complied with the NIC requirements, including those related to public 
involvement. Refer to Part Two, Section XVI for a discussion of the 
NIC.
    However, similar to the streamlined modification we finalized as 
L(9), we feel that this new streamlined modification warrants a Class 1 
modification with prior Agency approval. We feel that a Class 1 is 
appropriate considering that: we do not expect that there would be 
significant changes when requesting certain RCRA permit requirements to 
be waived; it would be applicable for a relatively short period of 
time; regulatory oversight is incorporated via approval of the 
modification request and; the intended goal of the modification is to 
achieve environmental improvement ultimately through implementation of 
more protective standards.
    d. How Will the New Streamlined Permit Modification Work? Our 
proposed approach allows for a waiver of specific RCRA permit 
requirements provided that you: (1) Submit a Class 1 permit 
modification request specifying the requested changes to the RCRA 
permit, with an accompanying explanation of why the changes are 
necessary and how the revised provisions will be sufficiently 
protective, and (2) obtain Agency approval prior to implementing the 
changes.\222\ When utilized to waive permit requirements during the 
performance test, you also must have an approved performance test plan 
prior to submitting your modification request. (We believe that the 
Class 1 modification with prior Agency approval will ensure that your 
proposed test conditions are reasonable with respect to your existing 
permit limits (i.e. that they are sufficiently protective); and that an 
approved performance test plan confirms that you have met the 
regulatory requirements for performance test plans.)
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    \222\ Refer to the new section in the RCRA permit modification 
table in 40 CFR 270.42, appendix I, L(10) and new regulatory 
language in 270.42(k), that must be used to waive specified permit 
requirements.
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    We propose that you submit your streamlined modification request in 
sufficient time to allow the Director a minimum of 30 days (with the 
option to extend the deadline for another 30 days) to review and 
approve your request. For purposes of performance testing, we propose 
that you submit your request at the time you receive approval of your 
performance test plan, which is 90 days in advance of the test and 
coincides with the time limitations imposed on the Director for 
approval. Additionally, we are requiring that the waiver of permit 
limits only be relevant during the actual testing events and during 
pretesting for an aggregate period of up to 720 hours of operation. In 
other words, it would not apply for the duration of time allotted to 
begin and complete the test (i.e., the entire 60 days).
    As a side note, we realize that some sources may not have an 
approved performance test plan by the date their test is scheduled to 
begin because the Administrator failed to approve (or deny) it within 
the specified time period, which could render this new streamlined 
modification impractical. However, we expect that sources would 
petition the Administrator to waive their performance test date for up 
to 6 months, with an additional 6 months possible, rather than to 
proceed with the performance test without the surety of an approved 
test plan.\223\
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    \223\ See 40 CFR 63.1207(e)(3) for performance test time 
extension requirements.
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B. How Will the Replacement Standards Affect Permitting for Phase I 
Sources?

1. Where Will Phase I Sources Be in Their Transition to MACT With 
Respect to Their RCRA Permits?
    We discussed earlier that by the time the Phase I Replacement 
standards and Phase II standards are finalized, most Phase I sources 
will have completed their initial comprehensive performance test and 
submitted their NOC documenting compliance with the MACT Interim 
Standards.\224\ This marks the point at which sources will begin to 
transition from RCRA permitting requirements to CAA requirements and 
title V permitting. For sources with RCRA permits, they must continue 
to comply with the operating standards and emission limits in their 
permits until any duplicative requirements are either removed through a 
permit modification, expire, or are automatically inactivated via a 
sunset clause contained in the permit. For sources operating under 
interim status,

[[Page 21322]]

they must comply with the RCRA interim status requirements until they 
demonstrate and document compliance with the MACT Interim Standards. We 
anticipate that sources who are in the process of renewing their RCRA 
permits would work with their permit writers to include sunset clauses 
to inactivate duplicative requirements upon compliance with the MACT 
Interim Standards. Given the permit actions taken during the transition 
period leading up to compliance with the Interim Standards, we believe 
that many sources will have had duplicative requirements removed from 
their permits by the time the Replacement Standards are promulgated. 
For sources that have not had their RCRA permits modified, we expect 
that they will proceed with a modification to remove duplicative 
requirements.\225\
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    \224\ Some sources will receive extensions of up to one year to 
conduct their initial comprehensive performance test (see 40 CFR 
63.1207(e)(3)). Therefore, their transition point will occur at a 
later time designated by the extension.
    \225\ A streamlined permit modification was developed in the 
1999 rule to allow the removal of duplicative conditions from RCRA 
permits (see Sec.  270.42, appendix I, section A.8).
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2. Where Will Phase I Sources Be in Their Transition to MACT With 
Respect to Their Title V Permits?
    With regard to title V permits, Phase I major and area sources were 
required to submit a title V permit application 12 months after the 
effective date of the 1999 rule--or were required to reopen existing 
title V permits with 3 or more years remaining in the permit term, 18 
months after the effective date--to include the MACT standards. Sources 
with less than 3 years remaining could wait until renewal to 
incorporate the 1999 standards.\226\ Upon promulgation of the Interim 
Standards on February 13, 2002, major sources were required to reopen 
their permits or could wait until renewal to include the revised 
standards according to the same time frames mentioned above. Therefore, 
we expect that all Phase I sources would have title V permits 
containing the MACT Interim Standards and potentially, operating 
standards in accordance with their DOC, at the time the Replacement 
Standards rule is promulgated. Furthermore, most sources will have 
initiated a significant modification to their permits to include the 
revised operating requirements of their NOC. Regardless of these 
required compliance activities leading up to the promulgation date of 
the Replacement Standards rule, Phase I sources will again need to 
reopen within 18 months or wait until renewal to incorporate the MACT 
Replacement standards.
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    \226\ Only major sources are required to reopen their title V 
permits when 3 or more years remain in the permit term. Even though 
area sources were subject to the same standards and title V permit 
requirements, they can wait until renewal regardless of the time 
remaining to incorporate new or revised standards. The reopening 
provisions of 40 CFR 70.7(f) and 71.7(f) only apply to major 
sources.
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3. What Is Different With Respect To Permitting in Today's Notice of 
Proposed Rulemaking?
    Based upon our decision to utilize the same general permitting 
approach as in the 1999 and Interim Standards rules, we expect sources 
to follow the same transition scheme as it relates to RCRA permit 
requirements and the CAA requirements and title V permitting for the 
Replacement Standards rule. One aspect, however, that was not addressed 
in those rules was how the permitting of new sources would be affected. 
Hence, we discuss approaches in this Notice of Proposed Rulemaking (see 
Section A.1. above) that would require them to obtain RCRA permits only 
for corrective action, general facility standards, other combustor 
specific concerns such as material handling, risk-based emission limits 
and operating requirements, and other hazardous waste management units 
at the source. Should the approach we are proposing be finalized, there 
may not be any operating requirements and emission standards to remove 
from their RCRA permits.
    We also discussed a new streamline permit modification procedure in 
section A.2. ``What Are the Proposed Changes to the RCRA Permitting 
Requirements that Will Facilitate the Transition to MACT?''. This new 
procedure allows sources to waive specific RCRA permit operating and 
emission limits during pretesting, performance testing, and other 
instances where there may be conflicts during the interim period 
between submission of the Documentation of Compliance and final RCRA 
permit modification.
    Another important difference is our proposal to codify the 
authority for permit writers to evaluate the need for and, where 
appropriate, require Site-Specific Risk Assessments (SSRA). We are also 
proposing to codify the authority for permit writers to add conditions 
to RCRA permits that they determine, based on the results of an SSRA, 
are necessary to protect human health and the environment. In doing so, 
our intent is to change the regulatory mechanism that is the basis for 
SSRAs, while retaining the same SSRA policy from a substantive 
standpoint. Under this approach, permitting authorities continue to 
have the responsibility to ensure the protectiveness of RCRA permits.
    Next, we have proposed to re-institute the NIC (see Part Two, 
Section XVI for a discussion of the NIC) for Phase I sources and to 
require the NIC for Phase II sources. While the NIC serves as a 
compliance planning tool and to promote early public involvement, it is 
also a requirement before the streamlined permit modification procedure 
in 40 CFR 270.42(j) and 270.42, appendix I, section L.9, can be 
utilized to make changes to either the combustor design or operations, 
in order to comply with the final Replacement Standards. Thus, sources 
who have not yet made the transition from their RCRA permits to title V 
permits must comply with the NIC requirements to take advantage of the 
streamlined permit modification.
    Last, a subtle difference pertaining to the transition scheme stems 
from the time span between compliance with the Interim Standards and 
the effective date of the Replacement Standards relative to RCRA 
permits. Sources who received extensions to the date for commencing 
their initial comprehensive performance test, whether a 6 month or 12 
month extension, will not be required to submit an NOC until either a 
few months before or just after the effective date of the final 
Replacement Standards rule. Therefore, these sources would be modifying 
their RCRA permits just before or after the effective date of the final 
rule. Nevertheless, we anticipate that sources will proceed with 
modification of their RCRA permits to remove duplicative requirements.

C. What Permitting Requirements Is EPA Proposing for Phase II Sources?

    Phase II sources are presently subject to the RCRA permitting 
requirements for hazardous waste combustors provided in 40 CFR 270.22 
and 270.66. We are proposing in today's notice to apply the same 
approach to permitting Phase II sources that we did for Phase I sources 
in the September 1999 rule. Specifically, we propose to:
    (1) Place the new Phase II emission standards only in the CAA 
regulations at 40 CFR part 63, subpart EEE, and rely on their 
implementation through the air program,
    (2) Specify that, with few exceptions, the analogous standards in 
the RCRA regulations no longer apply once a facility demonstrates 
compliance with the MACT standards in subpart EEE, and
    (3) Require that the new standards be incorporated into operating 
permits issued under title V of the CAA rather than be incorporated 
into RCRA permits.
    Our goal with regard to permitting Phase II sources remains the 
same as the goal that we had for Phase I sources--to accommodate the 
requirements of

[[Page 21323]]

both the RCRA and CAA statutes, while at the same time avoiding 
duplication between the two programs to the extent practicable. The 
permitting approach we developed for Phase I sources in the September 
1999 rule enables us to achieve this goal. In that rule, we amended the 
applicability of 40 CFR 270.19, 270.22, 270.62, and 270.66 so that once 
a source demonstrates compliance with the MACT standards, it is no 
longer subject to the full array of RCRA combustion permitting 
activities, unless the Director of the permitting agency decides to 
apply specific RCRA regulatory provisions, on a case-by-case basis, for 
purposes of information collection in accordance with Sec. Sec.  
270.10(k) and 270.32(b)(2). We are proposing to make a similar change 
to 40 CFR 270.22 and 270.66 for Phase II sources. In addition, we are 
proposing for Phase II sources, as we are for Phase I sources, that new 
sources not follow the RCRA permitting process for establishing 
combustor emissions and operating requirements. Of course, as for Phase 
I sources, Phase II sources would remain subject to the RCRA permitting 
requirements for all other aspects of their combustion unit and 
facility operations, including general facility standards, corrective 
action, other combustor-specific concerns such as materials handling, 
risk-based emission limits and operating requirements, as appropriate, 
and other hazardous waste management units at the site.\227\ Also, some 
sources will retain specific RCRA permitting requirements if they 
choose to comply with an alternative MACT standard; address startup, 
shutdown and malfunction events under RCRA rather than the CAA; or, if 
an area source, comply with the RCRA metals, particulate matter, or 
chlorine standards and associated requirements. It is also important to 
note that if you later decide to add a new combustion unit to your 
facility, you must first modify your RCRA permit to include the new 
unit. This is because your RCRA permit must reflect all hazardous waste 
management units at the facility. Although the emissions from the new 
unit will be regulated under the CAA MACT standards, as noted above, 
your RCRA permit must address any other related requirements for the 
new unit.
---------------------------------------------------------------------------

    \227\ Even though the RCRA air emission standards for combustors 
will no longer apply once compliance is demonstrated with MACT 
(except in certain cases), other RCRA air emission standards will 
continue to apply to other hazardous waste management units at the 
facility. For example, part 264, subpart CC, still applies to air 
emissions from tanks, surface impoundments, and containers.
---------------------------------------------------------------------------

1. What Other Permitting Requirements Are We Proposing To Apply To 
Phase II Sources?
    As part of the Phase I rule, we promulgated additional specific 
changes to the RCRA permitting requirements in 40 CFR part 270 to 
facilitate implementation of the new standards and permit transition 
from RCRA to the CAA. First, we added a streamlined RCRA permit 
modification process to allow sources to make changes to either their 
combustor design or operations, as necessary, in order to comply with 
the Phase I standards. This modification process, a Class 1 with prior 
Agency approval, was promulgated in the June 19, 1998 ``Fast Track'' 
rule and is provided in 40 CFR 270.42(j) and 270.42, appendix I, 
section L.9. See 63 FR 33785. Second, we further amended the Sec.  
270.42, appendix I permit modification table to add a new line item 
that streamlines modification procedures for removing conditions from a 
permit that are no longer applicable (e.g., because the standards upon 
which they are based are no longer applicable to the source). This new 
line item is a Class 1 modification requiring prior Agency approval and 
is provided in section A.8 of appendix I.\228\ Third, we added a new 
section, 40 CFR 270.235, to the RCRA permitting requirements that 
address startup, shutdown, and malfunction events and the integration 
of those requirements between the RCRA program and the CAA program. 
Fourth, we amended the requirements in 40 CFR 270.72 governing changes 
that facilities can make while they are operating under interim 
status.\229\ We believe that each of the above changes that we made to 
the RCRA permitting regulations for Phase I sources are also 
appropriate for Phase II sources and thus, are proposing that these 
same features apply to Phase II sources. They will serve to ease 
implementation of the new standards and transition combustion sources 
from RCRA to the CAA.
---------------------------------------------------------------------------

    \228\ It is important to note that you only may request the 
removal of duplicative combustion limits and conditions from your 
RCRA permit. Any risk-based conditions that are more stringent than 
the MACT requirements would be retained.
    \229\ Section 270.72(b) imposes a limit on the extent of the 
changes, stating that they cannot amount to ``reconstruction'' 
(defined in the regulation as ``when the capital investment in the 
changes to the facility exceeds 50 percent of the capital cost of a 
comparable entirely new hazardous waste management facility''). 
Although we did not expect the individual costs to perform changes 
required to comply with the MACT standards to exceed this 50 percent 
limit, the limit is cumulative for all changes at an interim status 
facility. Thus, conceivably there could be situations where MACT-
related changes would cause a source to exceed the limit. To ensure 
that the limit would not be a hindrance to MACT compliance, we added 
an exemption to paragraph (b) of that section for changes necessary 
to comply with standards under 40 CFR part 63, subpart EEE.
---------------------------------------------------------------------------

    We did not amend any title V regulations in 40 CFR parts 70 or 71 
for Phase I sources. It was our intent during the Phase I rulemaking, 
and continues to be our intent for Phase II, to rely on the existing 
air program to implement the new MACT requirements, including their 
incorporation into a title V operating permit. Thus, we are proposing 
that all current CAA title V requirements governing permit 
applications, permit content, permit issuance, renewal, reopenings and 
revisions will apply to air emissions from Phase II sources. In 
addition, the requirements of other CAA permitting programs, such as 
air construction permits, likewise will continue to apply, as 
appropriate. We also included provisions in the subpart EEE 
requirements that address the relationship between the standards and 
title V permits. Specifically, we stated in 40 CFR 63.1206(c)(1)(iv) 
and (v) that the operating requirements in the Notification of 
Compliance are applicable requirements for purposes of parts 70 and 71, 
and that these operating requirements will be incorporated into title V 
permits. We are proposing the same approach for the interface between 
the Phase II standards and title V permits.
2. What Other Permitting Requirements Are We Proposing in Today's 
Notice That Would Also Be Applicable to Phase II Sources?
    In today's notice, we are proposing three changes to the general 
permitting approach for all sources subject to part 63, subpart EEE, 
including Phase II sources. First, we are proposing to allow sources to 
waive specific RCRA permit operating and emission limits using a 
streamlined permit modification procedure. This would apply for 
pretesting, performance testing, and other instances where there may be 
conflicts during the interim period between submittal of the DOC and 
final RCRA permit modification. Second, we are proposing that new units 
not be required to obtain a RCRA permit that includes emission limits 
or conditions, with certain exceptions (e.g., more stringent risk-based 
limits). Third, we are proposing to codify the authority for permit 
writers to evaluate the need for and, where appropriate, require SSRAs. 
We are also proposing to codify the authority for permit writers to add 
conditions to RCRA permits that they determine, based on the results of 
an SSRA, are necessary to protect human health and the environment. We 
believe

[[Page 21324]]

that each of the above proposals are appropriate for Phase II as well 
as Phase I sources and, therefore, are applying them to all hazardous 
waste combustors subject to part 63, subpart EEE. See the discussions 
provided in A.1 and A.2 of this section.
3. How Will the Permitting Approach Work for Phase II Sources?
    In the preamble to the September 1999 rule, we discussed at length 
how to implement the new permitting approach, including aspects such as 
when and how to transition sources from RCRA permitting to title V. See 
64 FR 52981. We have also provided a fact sheet on permit transition in 
our Hazardous Waste Combustion NESHAP Toolkit, which is available at 
the following Internet address: http://www.epa.gov/epaoswer/hazwaste/combust/toolkit/index.htm. The information provided in the above-
mentioned preamble and the fact sheet is appropriate for Phase II as 
well as Phase I sources. Below is a summary of this information for 
sources that already have RCRA permits and for sources that are 
currently operating under RCRA Interim Status. The permitting approach 
for new sources is discussed earlier in A.1 of this section.
    a. Implementing the New Permitting Approach for Phase II Sources 
that Already Have RCRA Permits. If you already have a RCRA permit, you 
must continue to comply with the conditions in your permit until either 
they expire or your permitting authority modifies your permit to remove 
them. You can request a permit modification, using line item A.8 
provide in appendix I of Sec.  270.42, to request that your permitting 
authority remove any duplicative conditions once you have conducted 
your comprehensive performance test and submitted a Notification of 
Compliance documenting compliance to your CAA regulatory agency. The 
appropriate CAA regulatory agency in most cases will be the state 
environmental agency.
    When you submit your RCRA permit modification request you should 
identify the conditions in your RCRA permit that you believe should be 
removed. We recommend that you also attach a copy of your Notification 
of Compliance. This information will help the RCRA permit writer 
determine whether there are any risk-based conditions that need to 
remain in your RCRA permit. For example, any conditions imposed under 
RCRA omnibus authority, or similar state authority, based on the 
results of a site-specific risk assessment that are more stringent than 
the corresponding MACT standard or limitation documented in the 
Notification of Compliance would have to remain in the RCRA permit. You 
should also inform your RCRA permit writer if you intend to comply with 
any specific RCRA requirements in lieu of those provided in part 63, 
subpart EEE, such as the RCRA startup, shutdown, and malfunction 
requirements. Providing this information to the RCRA permit writer 
likely will expedite review of your permit modification request.
    We expect that in some situations RCRA permit writers may not 
approve a request to remove conditions until they know that their 
counterparts in the Air program have reviewed the Notification of 
Compliance and verified that the facility has successfully demonstrated 
compliance with the MACT standards. This may happen, for example, with 
facilities that have historically generated a lot of interest or 
concern from the community or that have had previous problems in 
maintaining compliance with performance standards. If you have received 
confirmation that the regulatory agency has made a Finding of 
Compliance based on your Notification of Compliance, we recommend you 
include that with your RCRA permit modification request as well. Once 
people in the Air program responsible for reviewing the Notification of 
Compliance have completed their evaluation of the documentation and 
test results, we encourage them to inform their RCRA counterparts. This 
courtesy will help RCRA permit writers complete their review of the 
RCRA permit modification requests, thereby facilitating the permit 
transition.
    b. Implementing the New Permitting Approach for Sources that Are 
Operating under RCRA Interim Status. If you are currently operating 
under RCRA interim status, you must continue to meet RCRA performance 
standards governing emissions of hazardous air pollutants in 40 CFR 
part 266 until you conduct your comprehensive performance test and 
submit your Notification of Compliance documenting compliance with the 
MACT standards to the regulatory agency. The RCRA combustion permitting 
procedures in 40 CFR part 270 also continue to apply until you 
demonstrate compliance.
    There is not a ``one size fits all'' answer to how facilities 
operating under RCRA interim status should make the transition. RCRA 
permit writers, in coordination with facility owners or operators, 
should map out the most appropriate route to follow in each case. In 
mapping out site-specific approaches to transition, both the regulators 
and the facility owners or operators should keep in mind the goal we 
mentioned earlier of minimizing the amount of time a facility might be 
subject to duplicative requirements under the two programs. Factors 
they should take into consideration include, but are not limited to the 
following. (1) The status of the facility in the RCRA permitting 
process at the time the final MACT rule is promulgated. For example--If 
a facility is on the verge of conducting a RCRA trial burn, it should 
proceed with the trial burn and continue through the RCRA permitting 
process. (2) The facility's anticipated schedule for demonstrating 
compliance with the MACT standards. For example--If the facility plans 
to come into compliance with the standards early, it may make sense to 
transition before completing the RCRA permitting process. (3) The 
priorities and schedule of the regulatory agency. For example--A state 
agency may have made certain commitments (e.g., to the public or to its 
state legislature) regarding their RCRA or CAA programs that might 
impact its decisions regarding the transition. (4) The level of 
environmental concern at a given site. For example--To make sure that 
the facility is being operated in a manner protective of human health 
and the environment, the regulatory agency may decide to proceed with 
RCRA permitting, including the site-specific risk assessment, rather 
than delay the RCRA process to coordinate with testing under MACT.
    If after evaluating all the relevant factors a decision is made to 
proceed with a RCRA permit in advance of a source's MACT compliance 
demonstration, we suggest including language to facilitate the eventual 
transition. Regulators can attach ``sunset'' provisions to those 
conditions that will no longer apply once a source demonstrates 
compliance with the part 63 subpart EEE standards.
    In making the transition from one program to the other, testing 
under one program should not be unnecessarily delayed in order to 
coordinate with testing required under the other. As proposed for Phase 
II, sources would be conducting periodic performance testing (every 
five years) anyway, just as the Phase I sources are required to do. In 
both our Hazardous Waste Minimization and Combustion Strategy and in 
the September 1999 Phase I rule, we emphasized the importance of 
bringing hazardous waste combustion units under enforceable controls 
that have been demonstrated to achieve compliance with performance 
standards. Stack testing is essentially

[[Page 21325]]

the way to make this demonstration, whether it is performed under the 
RCRA or CAA regulatory schemes, and so should be performed as 
expeditiously as possible.
4. How Do We Propose Regulating Phase II Area Sources?
    In today's Notice, we are not making a positive area source finding 
as we have with the Phase I area sources. However, we are using the 
``specific pollutants'' authority in section 112(c)(6) of the CAA to 
propose that area sources be subject to MACT standards only for certain 
hazardous air pollutants. Thus, area sources will be subject to title V 
permitting requirements for those pollutants specified per CAA section 
112(c)(6).
    Under 40 CFR 63.1(c)(2), area sources subject to MACT standards are 
also subject to title V permitting, unless the standards for the source 
category specifies 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 did not allow the 
states these options in the September 1999 rule for Phase I sources, 
and we are not proposing to offer them for Phase II sources either. 
Since the RCRA program does not make a distinction between regulating 
major and area sources and would no longer be able to address the 
pollutants covered by MACT (because the underlying RCRA standards in 40 
CFR parts 264, 265, and 266 would no longer be applicable once the 
source demonstrates compliance with subpart EEE), we believe that area 
sources should not be exempt from the title V permitting requirements. 
It is important that there not be a gap in permitting coverage as we 
implement the deferral from regulation under RCRA to regulation under 
the CAA. In addition, section 502(a) of the CAA requires that any area 
source exemptions from the title V permitting requirements be 
predicated on a finding that compliance with the requirements is 
impracticable, infeasible, or unnecessarily burdensome. We do not 
believe that the title V permitting requirements will be impracticable, 
infeasible, or unnecessarily burdensome for Phase II area sources, 
because these sources are already complying with RCRA permitting 
requirements.
    As explained above, we are using the ``specific pollutants'' 
authority to propose that area sources be subject to MACT standards 
only for certain hazardous air pollutants: dioxin/furans, mercury, DRE 
and carbon monoxide/hydrocarbons. (See Part Two, Section II.C.) For 
particulate matter, chlorine and HAP metals other than mercury, we are 
proposing that area sources have the option of complying with the MACT 
standards for Phase II major sources or continuing to comply with the 
RCRA emission standards and requirements. Those Phase II area sources 
that choose to comply with the RCRA standards and requirements will be 
subject to title V permits for some of their emissions and RCRA permits 
for others. In summary, regardless of whether an area source elects to 
comply with all or only the pollutants pursuant to CAA section 
112(c)(6), a title V permit will be required.

D. How Would this Proposal Affect the RCRA Site-Specific Risk 
Assessment Policy?

1. What Is the Site-Specific Risk Assessment Policy?
    In the September 30, 1999 Phase I rule, we articulated a revised 
Site-Specific Risk Assessment (SSRA) policy recommendation for 
hazardous waste burning incinerators, cement kilns and light-weight 
aggregate kilns. Specifically, we recommended that for hazardous waste 
combustors subject to the Phase I MACT standards, permitting 
authorities should evaluate the need for an SSRA on a case-by-case 
basis. We further stated that while SSRAs are not anticipated to be 
necessary for every facility, they should be conducted where there is 
some reason to believe that operation in accordance with the MACT 
standards alone may not be protective of human health and the 
environment. If the permitting authority concludes that a risk 
assessment is necessary for a particular combustor, the permitting 
authority must provide the factual and technical basis for its decision 
in the facility's administrative record. Should the SSRA demonstrate 
that supplemental requirements are needed to protect human health and 
the environment, additional conditions and limitations should be 
included in the facility's RCRA permit pursuant to the omnibus 
authority. The basis and supporting information for those supplemental 
requirements also must be documented in the facility's administrative 
record. For hazardous waste combustors not subject to the Phase I 
standards, we continued to recommend that SSRAs be conducted as part of 
the RCRA permitting process. See 64 FR 52841.\230\
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    \230\ We provided further clarification of the appropriate use 
of the SSRA policy and technical guidance in an April 10, 2003 
memorandum from Marianne Lamont Horinko, Assistant Administrator for 
OSWER, to the EPA Regional Administrators titled Use of the Site-
Specific Risk Assessment Policy and Guidance for Hazardous Waste 
Combustion Facilities. This document is available in the docket 
(Docket  RCRA-2003-0016) established for today's proposed 
action.
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2. Are SSRAs Likely To Be Necessary After Sources Comply With the Phase 
I Replacement Standards and Phase II Standards?
    As explained earlier, all Phase I replacement standards must be 
equivalent to or more stringent than the negotiated interim standards. 
Many of the replacement standards proposed in today's notice would be 
more stringent than the interim standards (e.g., 64 [mu]g/dscm as 
opposed to 120 [mu]g/dscm for the existing source cement kiln mercury 
standard). And, with the exception of the mercury standard for both new 
and existing LWAKs and the total chlorine standard for new LWAKs, they 
are also equivalent to or more stringent than the 1999-promulgated 
standards, which EPA determined to be generally protective in a 
national risk assessment conducted for that 
rulemaking.231, 232 For today's proposed action, we 
conducted a comparative risk analysis of the Phase I replacement 
standards to the 1999-promulgated Phase I standards. Specifically, we 
compared certain characteristics of the Phase I source universe as it 
exists today to the 1999 Phase I source universe to determine if there 
were any significant differences that might influence or impact the 
potential risk. We focused on the following four key characteristics: 
emission rates, stack gas characteristics, meteorological conditions, 
and exposed populations. Based on the results of our comparative 
analysis, we believe that the risk to human health and the environment 
from Phase I sources complying with the proposed replacement standards 
will be, for the most part, the same or less than the estimated risk 
from sources complying with the 1999-promulgated standards. See Part 
Four, Section IX, How Does the Proposed Rule Meet the RCRA 
Protectiveness Mandate?.
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    \231\ The 1999-promulgated total chlorine standard for new LWAKs 
was 41 ppmv. The proposed replacement standard is 150 ppmv. We do 
not view the total chlorine replacement standard as a concern 
because the 1999-promulgated total chlorine standard for existing 
sources was higher (230 ppmv) and found to be generally protective 
in the national risk assessment conducted for that rulemaking. With 
respect to risk from mercury for LWAKs, see ``Inferential Risk 
Analysis in Support of Standards for Emissions of Hazardous Air 
Pollutants from Hazardous Waste Combustors,'' prepared under 
contract to EPA by Research Triangle Institute, Research Triangle 
Park, NC.
    \232\ See Human Health and Ecological Risk Assessment Support to 
the Development of Technical Standards for Emissions from Combustion 
Units Burning Hazardous Wastes: Background Document, July 1999.

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[[Page 21326]]

    Although the replacement standards are generally equivalent to or 
more stringent than both the interim and 1999-promulgated standards, we 
cannot assess to what extent this may change the frequency with which 
SSRAs are determined to be necessary. In the end, the MACT standards 
are technology-based and so, risk analysis notwithstanding, cannot 
assure that emissions from each affected source will be protective of 
human health and the environment. For example, a particular source 
could emit types and concentrations of non-dioxin PICs different from 
those we modeled, and so could continue to pose risk not accounted for 
in our analysis. Sources' emissions of criteria pollutants, which are 
non-HAPs and so are beyond the direct scope of MACT, also could 
possibly pose risk which could necessitate site specific risk 
assessment.\233\ Another potential example involves emissions of 
nonmercury metal HAP by cement kilns and lightweight aggregate kilns. 
The semivolatile and low volatile metal thermal emission standards 
directly address emissions attributable to the hazardous waste, as 
opposed to a source's total HAP metal emissions. Thus, although these 
proposed limits reflect MACT, by normalizing the standards to thermal 
firing rate (for the appropriate reasons explained earlier), they do 
not create a HAP metal ``emissions cap.'' HAP metal emission 
contributions from nonhazardous waste fuels and raw materials are not 
directly regulated by this type of emission standard, but are rather 
controlled appropriately with the particulate matter standard.\234\
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    \233\ See 56 FR at 7145 (Feb. 21, 1991) explaining why there can 
be circumstances where a risk-based standard for particulate matter 
(a criteria pollutant) for hazardous waste combustion sources may be 
needed, and how such a standard could be integrated into the 
National Ambient Air Quality Standard implementation process.
    \234\ Particulate matter is an appropriate surrogate to control 
metal emissions in nonhazardous waste fuels and raw material in lieu 
of a numerical metal emission limit because a numerical metal 
emission standard may inappropriately control feedrate of HAP metals 
in the raw materials and fossil fuels (since such control would be 
neither replicable nor duplicable, and is not justified as a beyond-
the-floor standard).
---------------------------------------------------------------------------

    In contrast, RCRA permits can address the total emissions from the 
combustion unit, assuming an appropriate nexus with hazardous waste 
combustion. Thus, for those combustors that must comply with a thermal 
emission standard and that feed materials other than hazardous waste, 
the permitting authority may decide that an SSRA is appropriate to 
determine if additional limits (i.e., a total emissions cap) are 
necessary to ensure that all metal HAP emissions from the combustion 
unit remain at a level that is protective of human health and the 
environment.
    With respect to Phase II sources, the standards we are proposing in 
today's notice are significantly more stringent than the existing 
technical standards required under RCRA (40 CFR part 266, subpart H). 
To evaluate the protectiveness of the proposed Phase II standards, we 
conducted the same comparative risk analysis for Phase II sources that 
we conducted for Phase I sources. Specifically, we evaluated the 
differences between the 1999 Phase I source universe and the existing 
Phase II source universe with respect to the four key source 
characteristics mentioned above to determine if there were any 
significant differences that might influence or impact the potential 
risk. As discussed in the background document, (``Draft Technical 
Support Document for HWC MACT Replacement Standards, Volume V: 
Emissions Estimates and Engineering Costs'') we estimated emissions for 
each facility based on site-specific stack gas concentrations and flow 
rates measured during trial burn or compliance tests. We then assumed 
that sources would design their systems to meet an emission level below 
the proposed standard. For today's proposed standards, the design level 
is generally the lower of: (1) 70% of the standard; or (2) the 
arithmetic average of the emissions data of the best performing 
sources.\235\ We believe the comparative analysis lends support to our 
view that the standards for Phase II sources are generally protective. 
For a detailed discussion of the comparative risk analysis methodology 
and results, see the background document entitled ``Inferential Risk 
Analysis in Support of Standards for Emissions of Hazardous Air 
Pollutants from Hazardous Waste Combustors,'' prepared under contract 
to EPA by Research Triangle Institute, Research Triangle Park, NC.
---------------------------------------------------------------------------

    \235\ If available test data in our data base indicate that the 
source was emitting below the design level, we assumed that the 
source would continue to emit at the levels measured in test.
---------------------------------------------------------------------------

    As with the Phase I sources, we cannot reliably predict to what 
extent SSRAs will continue to be necessary for Phase II sources once 
they have complied with the MACT standards. In view of the standards 
alone there are at least three possible scenarios for which SSRAs may 
continue to be needed. First, we are proposing thermal emission 
standards for liquid fuel-fired boilers. Thus, similar to cement kilns 
and LWAKs, permitting authorities may determine that an SSRA is 
necessary to ensure that all emissions from liquid fuel-fired boilers 
are protective of human health and the environment. Second, we are 
proposing that liquid fuel-fired boilers with wet APCD or no APCD and 
solid fuel-fired boilers comply with a CO or total hydrocarbon limit as 
a surrogate for the dioxin/furan emission standard. Permitting 
authorities may determine that an SSRA is necessary for these sources 
if there is some concern that the CO or total hydrocarbon limit alone 
may not be adequately protective. Third, we are not proposing standards 
for all HAPs emitted by Phase II area sources. Instead, consistent with 
CAA section 112(c)(6), we are proposing MACT standards only for dioxin/
furans, mercury, carbon monoxide and hydrocarbons, and DRE. For the 
remaining metals, particulate matter and TCl, we are providing area 
sources with the option of complying with the MACT standards for major 
sources or continuing to comply with the existing RCRA technical 
standards. Sources that choose to comply with the RCRA standards may 
need to consider an SSRA, because the RCRA standards alone may not be 
sufficiently protective (i.e., since they do not address the potential 
risk from indirect exposures to long-term deposition of metals onto 
soils and surface waters). To date, we have identified only three area 
sources in the Phase II universe. Thus, the number of sources that 
could decide to continue complying with the above-mentioned RCRA 
standards is expected to be very limited.
    It is useful to note that there are other site-specific factors or 
circumstances beyond the standards themselves that can be important to 
the SSRA decision making process for an individual combustor. For 
example, a source's proximity to a water body or an endangered species 
habitat, repeated occurrences of contaminant advisories for nearby 
water bodies, the number of hazardous air pollutant emission sources 
within a facility and the surrounding community, whether or not the 
waste feed to the combustor is comprised of persistent, bioaccumulative 
or toxic contaminants, and sensitive receptors with potentially 
significantly different exposure pathways, such as Native Americans, 
will likely influence a permitting authority's decision of whether or 
not an SSRA is necessary. In addition, uncertainties inherent in our 
comparative risk analysis and the national risk assessment conducted in 
support of the 1999-promulgated

[[Page 21327]]

standards also may influence a permitting authority's decision. For 
example, the 1999 national risk assessment contained some uncertainties 
regarding the fate and transport of mercury in the environment and the 
biological significance of mercury exposures in fish. Another example 
relates to nondioxin products of incomplete combustion. Due to 
insufficient emissions data and parameter values, the 1999 national 
risk assessment did not include an evaluation of risk posed by 
nondioxin products of incomplete combustion. See 64 FR 52840 and 52841 
for additional discussion of uncertainties regarding the national risk 
assessment. Also, the comparative risk analysis conducted in support of 
today's action did not account for cumulative emissions at a source or 
background exposures from other sources.
3. What Changes Are EPA Proposing With Respect To the Site-Specific 
Risk Assessment Policy?
    As stated earlier in this section, we recommended in the preamble 
to the 1999 rulemaking that permitting authorities evaluate the need 
for an SSRA on a case-by-case basis for hazardous waste combustors 
subject to the Phase I MACT standards. For hazardous waste combustors 
not subject to the Phase I standards, we continued to recommend that 
SSRAs be conducted as part of the RCRA permitting process if necessary 
to protect human health and the environment. We indicated that the RCRA 
omnibus provision authorized permit writers to require applicants to 
submit SSRA results where an SSRA was determined to be necessary. 
Today, we are proposing to codify the authority for permit writers to 
evaluate the need for and, where appropriate, require SSRAs. We are 
also proposing to codify the authority for permit writers to add 
conditions to RCRA permits that they determine, based on the results of 
an SSRA, are necessary to protect human health and the environment. In 
doing so, our intent is to change the regulatory mechanism that is the 
basis for SSRAs, while retaining the same SSRA policy from a 
substantive standpoint. Under this approach, permitting authorities 
continue to have the responsibility to ensure the protectiveness of 
RCRA permits. We are requesting comment on this proposal.
    RCRA sections 3004(a) and (q) require that we promulgate standards 
for hazardous waste treatment, storage and disposal facilities and 
hazardous waste energy recovery facilities as may be necessary to 
protect human health and the environment. RCRA section 1006(b) directs 
us to integrate the provisions of RCRA with the appropriate provisions 
of the CAA and other federal statutes to the maximum extent 
practicable. Thus, to the extent that the RCRA emission standards and 
associated requirements promulgated under section 3004(a) or (q) are 
duplicative of the CAA MACT standards, section 1006(b) provides us with 
the authority to eliminate duplicative RCRA standards and associated 
requirements. For this reason, we have provided that most RCRA emission 
standards and associated requirements no longer apply to incinerators, 
cement kilns, and lightweight aggregate kilns once these sources 
demonstrate compliance with MACT requirements. As explained earlier, we 
are proposing to do the same in today's notice for solid fuel-fired 
boilers, liquid fuel-fired boilers and HCl production furnaces.
    Although the Phase I replacement and Phase II standards provide a 
high level of protection to human health and the environment, thereby 
allowing us to nationally defer the RCRA emission requirements to MACT, 
additional controls may be necessary on an individual source basis to 
ensure that adequate protection is achieved in accordance with RCRA. We 
believe that this will continue to be the case even after the Phase I 
replacement and Phase II standards are promulgated as discussed earlier 
in this section. Up to this point in time, we have relied exclusively 
on RCRA section 3005(c)(3) and its associated regulations (e.g., 40 CFR 
270.10(k)) when conducting or requiring a risk assessment on a site-
specific basis. Because risk assessments are likely to continue to be 
necessary at some facilities, we are proposing to explicitly codify the 
authority to require them on a case-by-case basis and add conditions to 
RCRA permits based on SSRA results under the authority of sections 
3004(a) and (q) and 3005 of RCRA. We continue to believe that section 
3005(c)(3) and its associated regulations provide the authority to 
require and perform SSRAs and to write permit conditions based on SSRA 
results. Indeed, as explained below, EPA will likely continue to 
include permit conditions based on the omnibus authority in some 
circumstances when conducting these activities, and state agencies in 
states with authorized programs will continue to rely on their own 
authorized equivalents, at least for some period of time. However, 
since we foresee that SSRAs will likely continue to be necessary at 
some hazardous waste combustion facilities, we are proposing to 
expressly codify these authorities for the convenience of both 
regulators and the regulated community.
    We are not proposing that SSRAs automatically be conducted for 
hazardous waste combustion units, because we continue to believe that 
the decision of whether or not a risk assessment is necessary must be 
made based upon relevant site-specific factors associated with an 
individual combustion unit and that there are combustion units for 
which an SSRA will not be necessary. We further believe that it is the 
permitting authority, with information provided by hazardous waste 
combustion facilities, that is best equipped to make this decision.
4. How Would the New SSRA Regulatory Provisions Work?
    The SSRA regulatory provisions are proposed under both base program 
authority (sections 3004(a) and 3005(b)) and HSWA authority (section 
3004(q)). Thus, where EPA or a state regulator has determined that a 
risk assessment is necessary, the applicability of the new provisions 
will vary according to the nature of the combustion unit in question 
(whether it is regulated under 3004(q), or only 3004(a) and 3005(b)), 
and the authorization status of the state. Depending on the facts, the 
new authority would be applicable, or the omnibus provision would 
remain the principal authority for requiring site-specific risk 
assessments and imposing risk-based conditions where appropriate.
    As explained in the state authorization section of this preamble 
(see Part Two, Section XIX.C), EPA does not consider these provisions 
to be either more or less stringent than the pre-existing federal 
program, since they simply make explicit an authority that has been and 
remains available under the omnibus authority and its implementing 
regulations. Thus, states with authorized equivalents to the federal 
omnibus authority will not be required to adopt these provisions, so 
long as they interpret their omnibus authority broadly enough to 
require risk assessments where necessary. Nonetheless, we encourage 
states to adopt these provisions to promote regulatory transparency.
    We are proposing to add a paragraph to the general permit 
application requirements of 40 CFR 270.10 to specifically allow a 
permit writer to require that a permittee or an applicant submit an 
SSRA or the information necessary for the regulatory agency to conduct 
an SSRA, if one is determined to be necessary. The permit writer may 
decide that an SSRA is needed if there

[[Page 21328]]

is some reason to believe that additional controls beyond those 
required pursuant to 40 CFR parts 63, 264 or 266 may be needed to 
ensure protection of human health and the environment under RCRA. We 
are also proposing to allow the permit writer to require that the 
applicant provide information, if needed, to make the decision of 
whether a risk assessment should be required. In addition, we are 
proposing to amend the applicability language of 40 CFR 270.19, 270.22, 
270.62, and 270.66 to allow a permit writer that has determined that an 
SSRA is necessary for a specific combustion unit to continue to apply 
the relevant requirements of these sections on a case-by-case basis and 
as they relate to the performance of the SSRA after the source has 
demonstrated compliance with the MACT standards.
    The basis for the decision to conduct the risk assessment must be 
included in the administrative record for the facility and made 
available to the public during the comment period for the draft permit. 
If the facility, or any other party, files comments on a draft permit 
decision objecting to the permitting authority's conclusions regarding 
the need for a risk assessment, the authority must respond fully to the 
comments. In addition, the risk assessment itself also must be included 
in the administrative record and made available to the public during 
the comment period for the permit. Any resulting permit conditions from 
the SSRA also must be documented and supported in the administrative 
record. We are proposing to add a paragraph to 40 CFR 270.32 to address 
the inclusion of conditions and limitations in RCRA permits as a result 
of the findings of an SSRA.
5. Why Is EPA Not Providing National Criteria for Determining When an 
SSRA Is or Is Not Necessary?
    We are not proposing national criteria for determining when an SSRA 
is necessary. In the preamble to the April 1996 Phase I NPRM, we 
provided a list of guiding factors which we later updated and modified 
in the preamble to the September 1999 final rulemaking. See 61 FR 17372 
and 64 FR 52842. We view these guiding factors as items that, because 
they may be relevant to the potential risk from a hazardous waste 
combustion unit, could be considered by a permitting authority when 
deciding if an SSRA is necessary. We did not, and do not, intend for 
them to be definitive criteria from which permitting authorities would 
make their decision. As we stated in 1999, we believed that the 
complexity of multi-pathway risk assessments precluded the conversion 
of these qualitative guiding factors into more definitive criteria. 
Since that time, we have reaffirmed our belief that the decision 
process regarding SSRAs does not lend itself to the application of 
required national criteria. Most combustors may be characterized using 
one or more of the qualitative guiding factors we provided in 1999, but 
not all. These factors were not intended to be an exclusive list of 
considerations, nor do we believe that this decision is necessarily 
susceptible to an exclusive list of factors. The decision whether to 
require a risk assessment is inherently site specific, and permitting 
authorities need to have the flexibility to evaluate a range of factors 
that can vary from facility to facility. In addition, it is useful to 
recognize that as risk assessment science continues to mature, the 
factors may change in terms of relative importance and it may not be 
prudent to obligate permitting authorities to an exclusive list that 
could not be easily adjusted to keep pace with scientific advancements.
    In a study conducted by U.S. EPA Region 4, the guiding factors were 
used to rank 13 hazardous waste combustion facilities into high, medium 
and low risk potential groupings to ascertain if the factors could be 
used as a prioritization tool for determining whether or not an SSRA 
was necessary. The region found that all facilities evaluated exhibited 
a ``high'' level of concern with respect to at least one or more site-
specific characteristics relating to the guiding factors and that 
further analysis was required before the region could be assured that 
the source would operate in a manner that is adequately protective 
under RCRA. As a result, the region concluded that the guiding factors 
alone could not be used to make a protectiveness finding. The region's 
study, which is entitled Technical Support Assistance of MACT 
Implementation Qualitative Risk Check is available in the docket 
(Docket RCRA-2003-0016) established for today's notice.
    Moreover, simply determining whether a combustor fits a particular 
guiding factor does not address the complex interplay that may exist 
between the guiding factors. Nor, does it measure the level of relative 
importance of one factor over another. For example, is the proximity of 
potentially sensitive receptors more important than multiple on-site 
emission points? For all of these reasons, we believe that codification 
of a list of factors would not be appropriate here.
6. What Is the Cement Kiln Recycling Coalition's SSRA Rulemaking 
Petition?
    On February 28, 2002, the Cement Kiln Recycling Coalition (CKRC) 
submitted a petition for rulemaking ``Petition Under RCRA Sec.  7004(a) 
For (1) Repeal of Regulations Issued Without Proper Legal Process and 
(2) Promulgation of Regulations If Necessary With Proper Legal 
Process'' to the Administrator containing two independent requests with 
respect to SSRAs. First, CKRC requested that we repeal the existing 
SSRA policy and technical guidance because it believes that the policy 
and guidance ``are regulations issued without appropriate notice and 
comment rulemaking procedures.'' Second, CKRC requested that after we 
repeal the policy and guidance, ``should EPA believe it can establish 
the need to require SSRAs in certain situations, CKRC urges EPA to 
undertake an appropriate notice and comment rulemaking process seeking 
to promulgate regulations establishing such requirements.''
    As stated in the petition, ``CKRC does not believe that these SSRA 
requirements are in any event necessary or appropriate.'' In addition, 
CKRC disagrees with our use of the RCRA omnibus provision as the 
authority to conduct SSRAs or to collect the information and data 
necessary to conduct SSRAs and further contends that the regulations 
associated with the omnibus provision are insufficient in detail. CKRC 
asserts that we have chosen to establish SSRA requirements through 
guidance documents. CKRC also raised the following three general 
concerns: (1) Whether an SSRA is needed for hazardous waste combustors 
that will be receiving a RCRA permit when the combustor is in full 
compliance with the RCRA boiler and industrial furnace regulations and/
or with the MACT regulations; (2) How an SSRA should be conducted; and 
(3) What is the threshold level for a ``yes'' or ``no'' decision that 
additional risk-based permit conditions are necessary. In support of 
its petition, CKRC refers to Appalachian Power Co. v. EPA, 208 F.3d 
1015 (D.C. Cir. 2000), GE v. EPA, 290 F.3d 377 (D.C. Cir. 2002), and 
Ethyl Corporation v. EPA, 306 F.3d 1144 (D.C. Cir. 2002). The petition 
is available in the docket established for today's proposed action.
    CKRC filed the petition filed under RCRA section 7004(a), which 
provides that: ``Any person may petition the Administrator for the 
promulgation, amendment, or repeal of any regulation under this Act. 
Within a reasonable time following receipt of such a petition, the

[[Page 21329]]

Administrator shall take action with respect to the petition and shall 
publish notice of such action in the Federal Register, together with 
the reasons therefor.''
    Shortly after receiving the petition, we conducted a preliminary 
evaluation of CKRC's concerns as stated in the petition.\236\ We 
determined that any decision regarding the petition should be made in 
coordination with our development of the proposed Replacement MACT 
standards for Phase I sources and the proposed new MACT standards for 
Phase II sources. Thus, we decided that today's notice was the most 
appropriate vehicle to announce and request comment on our tentative 
decision concerning the petition.
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    \236\ EPA does not consider the request to repeal EPA's guidance 
documents to be a valid petition under this section, since the 
documents are guidance documents, not regulations. Nonetheless, 
because CKRC has also petitioned the Agency to issue regulations, 
and to be responsive to issues raised by the regulated community, 
EPA has decided to use the procedure established in 40 CFR 260.20 
for section 7004 petitions to respond to both of CKRC's requests. 
EPA does not concede by relying on the section 7004(a) procedure 
that its guidance documents are regulations.
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    In the meantime, we believed that it was important to take certain 
measures to ensure that the SSRA policy and guidance were being used in 
the manner that we had intended. In an April 10, 2003 memorandum from 
Marianne Lamont Horinko, Assistant Administrator of the Office of Solid 
Waste and Emergency Response, to the U.S. EPA Regional Administrators, 
we took two of these measures. First, we requested that the regions 
review certain documents (e.g., regional memoranda, policy and guidance 
documents, Memoranda of Agreement of Grant Workplans with the states) 
to determine if any contained misleading or incorrect information 
concerning the SSRA policy and technical guidance. If any were found to 
contain misleading or incorrect information, we requested that the 
region take immediate measures to clarify or correct the information. 
Second, we reiterated, in detail, the appropriate use of the SSRA 
policy and guidance for hazardous waste combustors, as well as the 
appropriate use of the RCRA omnibus authority as it relates to SSRAs. 
In a May 15, 2002, memoranda from Robert Springer, Director of the 
Office of Solid Waste, to the RCRA Senior Policy Advisors, we took the 
third measure to ensure proper application of the SSRA policy by our 
regional permit writers. In this memorandum, we instituted an EPA 
headquarters review process of future regional decisions concerning the 
need for an SSRA for hazardous waste combustion units seeking a RCRA 
permit determination. Specifically, we requested that the regions 
provide us with a written summary of the basis for any future decisions 
to conduct or not conduct an SSRA. It is our intention that the review 
process focus on whether or not permit writers have adequately 
supported their decisions. It is important to point out that because 
many of the decisions regarding SSRAs are now being made at the state 
level, we do not yet know how many regional SSRA decision summaries 
will be submitted for our review. Both the April 10, 2003, and May 15, 
2003, memoranda are provided in the docket established for today's 
proposed action.
    EPA is in the process of an additional effort to ensure proper use 
of the guidance: we are reviewing the guidance documents themselves, 
and, to the extent we find language that could be construed as limiting 
discretion, we intend to revise the documents to make clear that they 
are non-binding. CKRC indicated in its petition that, in its view, the 
documents contain language that could be construed as mandatory. While 
EPA does not necessarily agree, and believes that, in context, it is 
clear that the guidance in the documents is discretionary, EPA is 
nonetheless reviewing the documents to ensure that they are carefully 
drafted.
    After consideration of the petition, we have made a tentative 
decision to partially grant and partially deny CKRC's requests. 
Specifically, we are proposing to deny CKRC's request that we repeal 
the SSRA policy and guidance and we are proposing to grant CKRC's 
request in part by promulgating an explicit authority to require SSRAs 
on a site-specific basis using notice and comment rulemaking 
procedures. We are requesting comment on our tentative decision.
    With respect to CKRC's first request that we repeal the SSRA policy 
and guidance, and in response to their specific concern of whether an 
SSRA is necessary for combustors that are in full compliance with the 
RCRA and/or MACT regulations, we believe that SSRAs do serve a useful 
purpose and can be necessary even if a facility is in full compliance 
with the existing RCRA and/or MACT technical standards. RCRA requires 
that all hazardous waste permits be protective of human health and the 
environment. As discussed in the preamble to the 1999 Phase I 
rulemaking, the existing RCRA incinerator and Boiler and Industrial 
Furnace (BIF) regulations do not address the potential risk that may be 
posed from indirect exposures to combustor emissions. See 64 FR 52828, 
52839-52842 (September 30, 1999). Further, the technical requirements 
associated with the RCRA standards have not been updated to reflect 
changes in technology or science for a decade or more and, thus, may 
not be sufficiently protective with respect to the potential risk from 
direct exposures either. For example, our knowledge regarding the 
formation, control and toxicity of dioxin/furans has vastly improved 
since the promulgation of the RCRA standards. Therefore, until such 
time that hazardous waste combustors comply with the MACT standards, 
SSRAs can serve a useful function in ensuring that RCRA combustor 
permits will be protective of human health and the environment.
    Moreover, even once the MACT standards are fully implemented for 
incinerators and BIFs, we believe that there may continue to be 
instances in which the permitting authority determines that additional 
protections are necessary (e.g., where site-specific conditions 
indicate that there may be a potential risk to a sensitive ecosystem or 
population), as was explained above in Section 2, Are SSRAs Likely to 
be Necessary After Sources Comply with the Phase I Replacement 
Standards and Phase II Standards? See also, the explanations at 64 FR 
52840-52841. Because there may continue to be a need for SSRAs at some 
level, we agree with CKRC that it would be appropriate to explicitly 
codify the authority to require SSRAs and SSRA-based permit conditions, 
for the sake of regulatory clarity and transparency (although we 
continue to believe that the RCRA omnibus provision provides sufficient 
authority to conduct SSRAs). EPA requests comment on the variety of 
site-specific circumstances that might give rise to the need for an 
SSRA, and whether other mechanisms might exist to address those 
circumstances.
    As stated earlier, CKRC raised three general concerns, the first of 
which we discussed in the preceding paragraphs. The second concern 
relates to the technical recommendations that EPA has offered for 
conducting an SSRA. CKRC disagrees with our use of guidance, instead 
arguing that EPA's recommendations should have been issued through the 
notice and comment rulemaking process.
    We disagree that the Agency's technical recommendations either must 
or should be issued as a regulation. Risk assessment--especially multi-
pathway, indirect exposure assessment--is a highly technical and 
evolving field. Any regulatory approach EPA might codify in this area 
is likely to become outdated, or at least artificially constraining, 
shortly after promulgation in ways that

[[Page 21330]]

EPA cannot anticipate now. In EPA's view, this is an area that is 
uniquely fitted for a guidance approach, rather than regulation. In 
fact, across Agency programs, EPA has generally adopted a guidance 
approach to risk assessment for exactly this reason. See, e.g., 
Guidelines for Reproductive Toxicity Risk Assessment, 61 FR 56274 
(October 31, 1996). EPA's Superfund program has not promulgated 
regulations specifying risk assessment methods. Instead, the program 
uses site-specific approaches for determining risk, employing methods 
offered in EPA guidance as appropriate. The same is true for the RCRA 
corrective action program. Although we have attempted to provide our 
guidance recommendations in a form that responds to or encompasses many 
of the issues that can arise when conducting an SSRA, we recognize that 
the flexibility to apply other methodologies, assumptions, or 
recommendations has been important to both regulators and the regulated 
community in terms of developing an appropriate site-specific 
protocol.\237\ For example, some of EPA's technical recommendations may 
not be appropriate for the combustion device in question, and risk 
assessors must have the flexibility to make adjustments for the 
specific conditions present at the source, and the state of risk 
assessment science at the time that the SSRA is being performed. As an 
obvious example, sources that are located in a dry, desert climate with 
no nearby permanent or temporary water bodies of concern should not be 
required to include a fisher exposure scenario in an SSRA. In addition, 
risk assessors should be free to use the most recent air modeling tools 
and toxicity values available rather than be limited to those that may 
be out-of-date because a regulation has not been revised following the 
development of the new tools or values. Guidance allows for this 
flexibility.
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    \237\ Permitting authorities, in some cases, have developed 
their own guidance methodologies responsive to the specific needs 
associated with their facilities. For example, North Carolina, 
Texas, and New York have each developed their own risk assessment 
methodologies. We think this flexibility employed in the field 
supports our judgment that risk assessment methodologies should not 
be codified.
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    CKRC points out the EPA codified certain parameters for BIF risk 
assessments, to show that it is possible to do so. While EPA agrees it 
is possible, the codification in the BIF area is the exception, not the 
rule. It has been our experience in implementing the BIF regulations 
that codification of certain risk parameters has proven to be overly 
constraining because risk science is a continually changing field. For 
example, by codifying the toxicity values, risk managers were not able 
to utilize more recent values available through EPA's Integrated Risk 
Information System (IRIS) \238\ and other resources. Also, shortly 
after we codified the air modeling guidelines in support of the risk 
parameters and procedures, the Air program revised their air modeling 
guidelines, rendering some of the BIF air modeling guidelines 
inconsistent and so, they were removed. Further, it is important to 
note that at the time of codification, BIF risk assessments were not 
intended to address indirect routes of exposure, thus making the 
parameters easier to implement. Today, however, risk assessments are 
more complex due to the necessary inclusion of multi-pathway and 
indirect exposure routes. Given the complexity of multi-pathway and 
indirect exposure assessments and the fact that risk science is 
continuously evolving, it would be difficult and again, overly 
constraining, to codify risk parameters today.
---------------------------------------------------------------------------

    \238\ IRIS is a collection of continuously updated chemical 
files which contain descriptive and quantitative information with 
respect to: oral reference doses and inhalation reference 
concentrations (RfDs and RfCs, respectively) for chronic 
noncarcinogenic health effects; and hazard identification, oral 
slope factors, and oral and inhalation unit risks for carcinogenic 
effects. For more information, see http://www.epa.gov/iris/index.html.
---------------------------------------------------------------------------

    We also believe that a guidance approach is consistent with the 
fact that permit writers must make site-specific decisions whether to 
do risk assessments at all. We expect that permit writers will reach 
their decisions based on different factors and concerns--in some cases, 
factors and concerns that we may not have identified at this time. We 
think that it makes little sense to allow this kind of flexibility 
regarding whether to do a risk assessment and for what purposes, while 
prescribing how one must be conducted if one is required.
    CKRC further contends that the guidance is overly conservative and 
constitutes ``a confusing pattern of drafts over a number of years in a 
seemingly endless fashion'' that has resulted in their members 
incurring significant costs. Because of the variability in the many 
factors that influence the risk from hazardous waste combustors, the 
guidance contains some conservative recommendations and assumptions in 
order to address this wide range. However, based on input from users of 
the guidance, we have attempted to correct the recommendations and 
assumptions that we consider to be overly conservative and, as stated 
previously, because they are guidance recommendations and not 
requirements, the risk assessor may choose not to follow them. More 
recently, we have solicited public and peer review comments on the 1998 
guidance,\239\ and are in the process of revising it based on the 
comments received. This includes comments CKRC submitted related to the 
components of the guidance they contended were overly 
conservative.\240\
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    \239\ USEPA. ``Human Health Risk Assessment Protocol for 
Hazardous Waste Combustion Facilities'' EPA-520-D-98-001A, B&C. 
External Peer Review Draft, 1998. (http://www.epa.gov/ epaoswer/
hazwaste/combust/risk.htm)
    \240\ We are not responding to the specific comments here, but 
will respond to them as part of the public process for developing 
the final guidance documents.
---------------------------------------------------------------------------

    With respect to CKRC's assertion that the guidance is ``a confusing 
pattern of drafts over a number of years'', we acknowledge that we have 
issued a number of guidance documents since 1990. However, we disagree 
that this has resulted in a confusing pattern of drafts. The 
development and release of the guidance documents correspond to three 
specific regulatory time periods in the area of hazardous waste 
combustion. In addition, the issuance of subsequent versions relates to 
the fact that the Agency has repeatedly solicited public and peer 
review comments on its technical guidance, and has built upon the 
experience of regulators and facilities in using earlier guidance.
    In 1990, EPA developed its initial guidance document during the 
same time period as the RCRA BIF emission standards. In 1993, we 
released an addendum to the 1990 guidance in response to the draft 
Hazardous Waste Minimization and Combustion Strategy and our increasing 
concerns about the potential impacts from indirect routes of exposure, 
and solicited comments from the public and the Science Advisory Board. 
A revised document taking into account these comments was issued one 
year later.\241\
---------------------------------------------------------------------------

    \241\ 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. (These 
documents are available as part of the ``Exposure Assessment 
Guidance for RCRA Hazardous Waste Combustion Facilities'' EPA530-R-
R-94-021. Copies may be ordered through the National Service Center 
for Environmental Publications' Web site at http://www.epa.gov/ncepihom/)
---------------------------------------------------------------------------

    At the time that we were developing the Phase 1 MACT standards, we 
again updated our combustion risk assessment guidance by releasing a 
document specifically addressing human health risk in 1998 and one 
addressing ecological risk in 1999, again soliciting public input and 
peer review on these

[[Page 21331]]

documents.\242\ For purposes of clarity, both of these documents refer 
to all earlier guidance where appropriate and discuss briefly the 
progression of the guidance. Although the 1998 human health guidance 
and the 1999 ecological guidance provide our current thinking regarding 
SSRA methodology for hazardous waste combustors, we noted to our permit 
writers that we recommended that they should continue to use the 1994 
guidance for those SSRAs that were in progress.
---------------------------------------------------------------------------

    \242\ We noted earlier that the 1998 guidance is currently being 
revised in consideration of public and peer review comments 
received. With respect to the 1999 guidance (USEPA. ``Screening 
Level Ecological Risk Assessment Protocol for Hazardous Waste 
Combustion Facilities'' EPA-530-D-99-001A, B&C. Peer Review Draft, 
1999), we solicited public comment and plan to conduct a peer 
review. (http://www.epa.gov/epaoswer/hazwaste/combust/ecorisk.htm)
---------------------------------------------------------------------------

    Although CKRC claims to find these guidance documents confusing, 
EPA's judgment is that most interested parties--both regulators and the 
regulated community--have found the guidance to be useful, and that the 
documents have substantially reduced the uncertainty and confusion that 
surrounded multi-pathway risk assessments a decade ago. As stated 
above, no one is obligated to follow this guidance, and regulators 
often depart from it; but EPA believes it has been extremely helpful on 
the whole, rather than confusing.
    CKRC has alleged that SSRA's typically cost between $200,000 and 
$1,000,000 for an individual facility. We are aware that prior to the 
release of the 1998 guidance, combustion risk assessments were more 
costly than we understand them to be today. For an individual facility, 
we do not know to what extent these costs are attributed to the act of 
conducting a risk assessment, to recommendations provided in our 
guidance, to changes that the facility chose to make during the risk 
assessment, or the facility's desire to develop its own site-specific 
protocol. Not including the collection and analysis of emission risk 
data, we have been advised that the cost of an average SSRA today is 
approximately $84,000. (See document entitled Hazardous Waste 
Combustion MACT--Replacement Standards: Proposed Rule. Preliminary Cost 
Assessment for Site Specific Risk Assessment, November, 2003, as 
provided in the docket for today's action.) The emission risk data is 
projected to add on average between $57,000 (if the facility collects 
its emission risk data at the same time as its emission standards 
performance data) and $285,000 (if the facility must conduct a separate 
emission test solely for the purpose of collecting data for the SSRA). 
Therefore, including emission data collection, the average cost of an 
SSRA is between $141,000 and $370,000. This is considerably less than 
the cost range provided by CKRC of $200,000 to $1,000,000. 
Additionally, EPA's upper bound cost of $370,000 is significantly less 
than the upper bound cost of $1,300,000, as reported by CKRC in their 
petition (and the attached affidavit).\243\ We believe that the cost of 
SSRAs has decreased over time, particularly since the release of the 
1998 guidance. This may be in large part because the 1998 guidance is 
much more comprehensive than previous guidance documents and because 
private software companies have developed computer programs based on 
the guidance, which can further decrease costs associated with the risk 
calculations for each exposure scenario.
---------------------------------------------------------------------------

    \243\ The cost ranges for CKRC include both the cost of risk 
assessments and emission data collection. In its petition, CKRC 
provided a range of costs ($100,000 to $500,000 for risk assessments 
and $100,000 to $500,000 for emission data collection), but also 
provided an upper bound cost ($728,297 for a risk assessment and 
$588,790 for emission data collection, plus additional permit costs 
to equate to $1.3M).
---------------------------------------------------------------------------

    CKRC also expressed specific concern that it and its members have 
been denied an opportunity to comment on the combustion risk assessment 
guidance documents. We strongly disagree with this assertion. We have 
repeatedly sought public comment on the guidance documents. For the 
1998 human health guidance we not only requested public comment, but 
also submitted the document for an external peer review and held a peer 
review meeting which was open to the public. Since the peer review 
meeting, we have been incorporating both the public and peer review 
comments into the human health guidance. While we have not yet 
completed this task and released a final document, any member of the 
public may at any time discuss any concerns that they have with our 
recommendations. In addition, regardless of whether a risk assessor 
uses the recommendations provided in our guidance or not, we have 
encouraged the permit writer and facility representatives to meet prior 
to any analysis to discuss the appropriate risk methodology and data 
input needs for an SSRA. Such a meeting allows both the permitting 
authority and the facility the opportunity to raise questions and 
objections concerning the appropriateness of different methodologies, 
assumptions, or default values and their application to the hazardous 
waste combustor. Facility representatives and any member of the public 
also may comment on the risk assessment methodology as part of the 
public comment process associated with the RCRA permit.
    The third general concern raised by CKRC in its petition was that 
we had not provided a threshold level for a ``yes'' or ``no'' decision 
to trigger the need for additional risk-based permit conditions. EPA 
agrees that its guidance does not establish a bright-line threshold 
level for determining whether to impose additional permit conditions; 
such a binding requirement would only be appropriately established 
through rulemaking. However, EPA has provided recommendations about the 
overall targets for acceptable risk levels. See USEPA. Implementation 
of Exposure Assessment Guidance for RCRA Hazardous Waste Combustion 
Facilities, Draft, 1994. Moreover, we do not intend to codify our 
recommended target levels for some of the same reasons that we are not 
proposing to codify the risk assessment technical guidance. Our 
recommended target levels provide risk managers with a starting point 
from which to determine if a combustor's potential risk may or may not 
be acceptable. However, we believe that it is important, and indeed 
essential, that risk managers be afforded sufficient flexibility to 
apply different target levels as dictated by the circumstances 
surrounding the combustor. For example, a risk manager may wish to 
apply a more stringent carcinogenic target level for a combustor that 
is located in a densely populated area with a high concentration of 
industrial emission sources.
    In summary, we have made a tentative decision to deny CKRC's 
request that we repeal the SSRA policy and guidance and to grant CKRC's 
request in part by proposing to codify the authority to require SSRAs. 
We are not proposing to codify the SSRA guidance or our recommended 
risk methodology for hazardous waste combustors. We are requesting 
comment on our tentative decision.

XVIII. What Alternatives to the Particulate Matter Standard Is EPA 
Proposing or Requesting Comment On?

    As discussed in Part Two, Section IV.C, we are proposing 
particulate matter standards as surrogates to control metal HAP.\244\ 
We are not proposing numerical metal HAP emission standards that would 
have accounted for all metal HAP because we generally do not have as 
much compliance test

[[Page 21332]]

emissions information in our database for the nonenumerated metal HAP 
compared to the enumerated metal HAP,\245\ and because we believe that 
a particulate matter standard, in lieu of emission standards that 
directly regulate all the metals in all feedstreams, simplifies 
compliance activities.
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    \244\ Particulate matter is not a listed HAP pursuant to CAA 
112(b).
    \245\ ``Enumerated'' metals are those HAP metals that are 
directly controlled with an emission limit, i.e., lead, cadmium, 
arsenic, beryllium, and chromium. The remaining nonmercury metal HAP 
are controlled using particulate matter as a surrogate.
---------------------------------------------------------------------------

    Nonetheless, we are today proposing an alternative to the 
particulate matter standard for incinerators, liquid fuel-fired 
boilers, and solid fuel-fired boilers that is conceptually similar to 
the alternative metal emission control requirements that were 
previously promulgated for incinerators. We are also requesting comment 
on another alternative to the particulate matter standard that would 
apply to all source categories that would be subject to particulate 
matter standards (i.e., all source categories except hydrochloric acid 
production furnaces).
    We discuss these two different alternatives below.

A. What Alternative to the Particulate Matter Standard Is EPA Proposing 
For Incinerators, Liquid Fuel-Fired Boilers, and Solid Fuel-Fired 
Boilers?

    We promulgated an alternative to the particulate matter standard 
for incinerators feeding low levels of metals in the July 3, 2001, 
direct final rule. See 66 FR at 35093. Today we propose a simplified 
alternative to the particulate matter standard for incinerators, and we 
propose to expand the provision to also apply to liquid and solid fuel-
fired boilers. Below, we first describe the alternative that was 
originally promulgated for incinerators, after which we describe the 
simplified approach and our rationale for proposing it.
    The July 3, 2001, final rule allows incinerators to operate under 
alternative metal emission control requirements reflecting MACT in lieu 
of complying with the 0.015 gr/dscf particulate emission standard. 
Under the alternative, no particulate matter emission standard applies 
to incinerators under subpart EEE; however, the incinerator remains 
subject to the RCRA particulate matter standard of 0.08 gr/dscf 
pursuant to Sec.  264.343(c). This is because Clean Air Act standards 
can supplant RCRA standards only when the CAA standard is sufficiently 
protective of human health and the environment to make the RCRA 
standard duplicative (within the meaning of RCRA section 1006 (b) 
(3)).\246\ See Part Two, Section XVII.D.
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    \246\ Sources electing to comply with these alternative 
requirements thus remain subject to the RCRA PM standard in their 
RCRA permit. The RCRA permit must include applicable operating 
limits that ensure compliance with the RCRA PM limit.
---------------------------------------------------------------------------

    This previously promulgated alternative to the particulate matter 
standard has three components. The first component is simply to meet 
metal emission limitations for semivolatile and low volatile metals. 
The emission limitations apply to both enumerated and non-enumerated 
metal HAP, excluding mercury. Enumerated semivolatile metals are those 
metals that are directly controlled with the numerical semivolatile 
emission standard, i.e., cadmium and lead. Enumerated low volatile 
metals are those metals that are directly controlled with the numerical 
low volatile metals emission standard, i.e., arsenic, beryllium and 
chromium. Non-enumerated metals are those remaining metal HAP: 
antimony, cobalt, manganese, nickel, and selenium that are not 
controlled directly with an emission standard, but are rather 
controlled through the surrogate particulate matter standard.\247\ For 
purposes of these alternative requirements, the non-enumerated metals 
are classified as either a semivolatile or a low volatile metal, and 
included in the calculation of compliance with the corresponding 
emissions limit. The level of the standard is the same as that which 
applies to other incinerators, but the standard would apply to all 
metal HAP, not just those enumerated in the present low volatile metal 
and semivolatile metal standards.
---------------------------------------------------------------------------

    \247\ Please note that the particulate matter standard is not 
redundant to the semivolatile and low volatile metal standards. 
Although controlling particulate matter also controls semivolatile 
and low volatile metals in combustion gas, these metals can also be 
controlled by feedrate control. Thus, sources can achieve the 
emission standard for semivolatile and low volatile metals primarily 
by feedrate control. In such cases, the particulate matter standard 
would be controlling nonenumerated metals primarily.
---------------------------------------------------------------------------

    The second component is a requirement for the incinerator to 
demonstrate that it is using reasonable hazardous waste metal feed 
control, i.e., a defined metal feedrate that is better than the MACT-
defining metal feed floor control level. The third component is a 
requirement for the incinerator to demonstrate that its air pollution 
control system achieves, at a minimum, a 90 percent system removal 
efficiency for semivolatile metals.
    Today we propose a simplified version of the above described 
alternative in that we propose to require you to comply only with the 
first component described above, which is to achieve metal emission 
standards for semivolatile and low volatile metals. As discussed above, 
the level of the proposed standard is the same as that which applies to 
other sources, but the standard would apply to all metal HAP, not just 
those enumerated in the present semivolatile and low volatile metal 
standards. As with the previously promulgated alternative, no 
particulate matter emission standard would apply to these sources under 
subpart EEE; however, sources would remain subject to the RCRA 
particulate matter standard of 0.08 gr/dscf pursuant to Sec. Sec.  
264.343(c) or 266.105.
    We propose to eliminate the requirements for you to demonstrate 
that: (1) You are using reasonable hazardous waste metal feed control, 
i.e., a defined metal feed control that is better than the MACT-
defining feed control level; and (2) your source is equipped with an 
air pollution control system that achieves at least a 90 percent system 
removal efficiency for semivolatile metals. We believe these two 
requirements are not necessary to ensure you are in fact controlling 
metals below MACT levels given that all sources electing to comply with 
this alternative must limit both the enumerated metals and non-
enumerated metals to levels below the proposed levels that apply only 
to enumerated metals. Today's proposed approach, in effect, lowers the 
existing semivolatile and low volatile metal emissions limits because 
the contribution of nonenumerated metals must be accounted for when 
achieving the same numerical semivolatile and low volatile emission 
limits. We believe this is appropriate because this effectively lower 
emissions limit for enumerated metals compensates for the lower 
emission levels that would have been achieved if the source used a 
particulate matter control device capable of achieving the particulate 
matter standard. Put another way, we regard this emission limitation as 
an equivalent means of meeting the standard for HAP metals (except 
mercury) already established in the rule.
    As discussed above, the approach we promulgated on July 3, 2001 
required you, in practice, to feed low levels of metals on a continuous 
basis in order to qualify for the alternative. The rule required that 
the source's feed control level must be equivalent to or lower than 25% 
of the MACT-defining hazardous waste feed control level. We considered 
whether it would be appropriate to also apply such a

[[Page 21333]]

qualification requirement to today's proposed alternative. 
Unfortunately, the methodology used to calculate today's proposed 
emission standards does not base the standards on a specific MACT-
defining feed control level. Thus, we do not have a MACT feed control 
level that we can readily use to define an appropriate low feed control 
level. We request comment on whether it is appropriate and/or necessary 
to establish a minimum feed control level, and if so, how it could be 
determined.
1. What Emission Limitation Must Incinerators Comply With Under This 
Alternative?
    For existing incinerators, the emissions limits under this 
alternative would be: (1) A semivolatile metal emission limit of 59 
[mu]g/dscm for the combined emissions of lead, cadmium, and selenium; 
and (2) a low volatile metal emission limit of 84 [mu]g/dscm for 
combined emissions of arsenic, beryllium, chromium, antimony, cobalt, 
manganese, and nickel (all emissions corrected to 7% oxygen).
    For new sources, the emissions limits would be: (1) a semivolatile 
emission limit of 7 [mu]g/dscm for combined emissions of lead, cadmium, 
and selenium; and (2) a low volatile emission limit of 9 [mu]g/dscm for 
emissions of arsenic, beryllium, chromium, antimony, cobalt, manganese, 
and nickel (all emissions corrected to 7% oxygen).
2. What Emission Limitation Must Liquid Fuel-Fired Boilers Comply With 
Under This Alternative?
    For existing liquid fuel-fired boilers, the emissions limits under 
this alternative would be: (1) A semivolatile metal emission limit of 
1.1E-5 lb/MM BTU for the combined emissions of lead, cadmium, and 
selenium; and (2) a low volatile metal emission limit of 7.7E-5 lb/MM 
BTU for combined emissions of arsenic, beryllium, chromium, antimony, 
cobalt, manganese, and nickel (all emissions corrected to 7% oxygen).
    For new sources, the emissions limits would be: (1) A semivolatile 
metal emission limit of 4.3E-6 lb/MM BTU for combined emissions of 
lead, cadmium, and selenium; and (2) a low volatile metal emission 
limit of 3.6E-5 lb/MM BTU for emissions of arsenic, beryllium, 
chromium, antimony, cobalt, manganese, and nickel (all emissions 
corrected to 7% oxygen).
3. What Emission Limitation Must Solid Fuel-Fired Boilers Comply With 
Under This Alternative?
    For existing solid fuel-fired boilers, the emissions limits under 
this alternative would be: (1) A semivolatile metal emission limit of 
170 [mu]g/dscm for the combined emissions of lead, cadmium, and 
selenium; and (2) a low volatile metal emission limit of 210 [mu]g/dscm 
for combined emissions of arsenic, beryllium, chromium, antimony, 
cobalt, manganese, and nickel (all emissions corrected to 7% oxygen).
    For new sources, the emissions limits would be: (1) A semivolatile 
metal emission limit of 170 [mu]g/dscm for combined emissions of lead, 
cadmium, and selenium; and (2) a low volatile metal emission limit of 
190 [mu]g/dscm for emissions of arsenic, beryllium, chromium, antimony, 
cobalt, manganese, and nickel (all emissions corrected to 7% oxygen).
4. Why Don't We Offer This Alternative to Lightweight Aggregate Kilns 
and Cement Kilns?
    This alternative is intended to apply to sources that feed de 
minimis levels of metal HAP. We do not believe hazardous waste burning 
lightweight aggregate kilns and cement kilns feed these metals at de 
minimis levels primarily because raw materials and coal that is co-
fired may contain these metal HAP, and because hazardous waste that is 
combusted by sources that receive off-site hazardous waste shipments 
(i.e., commercial hazardous waste combustors) typically contain these 
metal HAP. Thus, we think that allowing this alternative would not be 
of practical significance because we do not believe these sources could 
meet the standard. As a result, we are not proposing this alternative 
for these source categories.

B. What Alternative to the Particulate Matter Standard Is EPA 
Requesting Comment On?

    As previously discussed, we do not have sufficient metal HAP 
compliance data to calculate MACT floors that would account for all the 
nonmercury metal HAP in all feedstreams. We discuss below, however, an 
alternative approach to the particulate matter standard that could be 
implemented if sources monitor and collect nonmercury metal HAP feed 
concentration data prior to the compliance date. Such an approach, if 
promulgated, would result in site-specific metal HAP emission limits 
that would be dependent, in part, on each source's average feed 
concentration levels of metal HAP in their hazardous and nonhazardous 
waste feedstreams, and, for energy recovery units, each source's 
hazardous waste firing rate. We discuss this alternative below, and we 
request comment as to whether this approach is appropriate given the 
complexities associated with its implementation. Also see USEPA, 
``Draft Technical Support Document for HWC MACT Replacement Standards, 
Volume IV: Compliance With MACT Standards,'' March 2004, Chapter 23.9, 
for more discussion.
1. What Are the Components of the Total Metal Emissions Limitations?
    This total metal emission limitation would regulate all nonmercury 
metal HAP with separate semivolatile HAP metal and low volatile HAP 
metal emission limits. Each semivolatile and low volatile metal limit 
would have separate MACT components that would control and limit 
enumerated and nonenumerated metal HAP emissions that are attributable 
to: (1) Hazardous waste feedstreams; (2) nonhazardous waste, non-fuel 
feedstreams (e.g., cement kiln raw material); and (3) nonhazardous 
waste fuels (e.g., coal). Some of these components may or may not apply 
depending on the source category. Each semivolatile and low volatile 
metal component is converted to a mass emission limitation, and each 
source's resultant total metal emissions would be limited to the 
summation of each of the applicable components. We describe these MACT 
components below.
    a. Energy Recovery Units: Allowable Enumerated Semivolatile and Low 
Volatile Metal Emissions Attributable to the Hazardous Waste. This 
first component limits enumerated metal emissions attributable to 
hazardous waste feedstreams from energy recovery units, i.e., liquid 
boilers, cement kilns, and lightweight aggregate kilns, and is 
equivalent to the enumerated semivolatile and low volatile metal mass 
emission rate that would be allowed by today's proposed standards. Each 
source's allowable mass emission rate limit for this component would be 
equivalent to its associated hazardous waste thermal feed rate 
(expressed as million Btu hazardous waste per hour) multiplied by the 
proposed semivolatile and low volatile metal thermal emission standard.
    b. Solid Fuel-Fired Boilers and Incinerators: Allowable Enumerated 
Semivolatile and Low Volatile Metal Emissions Attributable to All 
Feedstreams. This second component applies only to solid fuel-fired 
boilers and incinerators, and limits enumerated

[[Page 21334]]

metal mass emissions attributable to all feedstreams, i.e., hazardous 
waste, nonhazardous waste, and nonhazardous waste fuels. This component 
limit is equivalent to the enumerated semivolatile and low volatile 
metal mass emission rate that would be allowed by today's proposed 
standards. Today's proposed standards for incinerators and solid-fuel-
fired boilers limits total emissions from all feedstreams, and are 
expressed as stack gas concentration limits. Each source's allowable 
mass emission rate limit for this component would be equivalent to its 
gas flowrate multiplied by the proposed standard.
    c. All Source Categories: Allowable Nonenumerated Semivolatile and 
Low Volatile Metal Emissions Attributable to the Hazardous Waste. This 
third component limits nonenumerated semivolatile and low volatile 
metal emissions attributable to hazardous waste feedstreams, and is 
applicable to all source categories. We currently do not have 
sufficient data to calculate a MACT emission limitation for 
nonenumerated metals in the hazardous waste. As a result, sources 
complying with this alternative would be required to collect three 
years of nonenumerated semivolatile and low volatile metal hazardous 
waste feed control concentrations.\248\ Incinerators and solid fuel-
fired boilers would be required to collect hazardous waste maximum 
theoretical emissions concentrations, and energy recovery units would 
be required to collect three years of hazardous waste thermal feed 
concentration data for these metal groups.\249\ Each incinerator and 
solid fuel-fired boiler's allowable semivolatile and low volatile metal 
mass emission rate for this component would be equivalent to its 
associated three year average hazardous waste maximum theoretical 
emissions concentrations for each metal group multiplied by: (1) One 
minus the MACT system removal efficiency; and (2) its associated 
volumetric gas flow rate. Each energy recovery unit's allowable mass 
emission rate for this component would be equivalent to its associated 
three year average hazardous waste thermal feed concentration for each 
metal group multiplied by: (1) One minus the MACT system removal 
efficiency; and (2) its associated hazardous waste thermal feedrate 
(expressed as million Btu hazardous waste per hour). The MACT system 
removal efficiency that would be applied separately for semivolatile 
metals and low volatile metals would be determined as described in Part 
Two, Section VI.G.5 for each source category.
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    \248\ We request comment on how such an approach would work for 
new sources, given that new sources may not have historical feed 
concentration data at the time they begin operations.
    \249\ Each source would be required to calculate its associated 
three year average nonenumerated metal hazardous waste 
concentrations for both semivolatile metals (selenium) and low 
volatile metals (antimony, cobalt, manganese, and nickel) expressed 
in either hazardous waste thermal concentrations, i.e., pounds per 
million Btus (for energy recovery units) or maximum theoretical 
emissions concentrations, i.e., pounds per dry standard cubic feet 
(for incinerators and solid fuel-fired boilers).
---------------------------------------------------------------------------

    d. Energy Recovery Units: Enumerated and Nonenumerated Metal HAP 
Emissions Attributable to Nonhazardous Waste Fuels. The fourth 
component limits enumerated and nonenumerated semivolatile and low 
volatile metal mass emissions attributable to nonhazardous waste fuels 
(e.g., coal) and is applicable to energy recovery units, i.e., cement 
kilns, lightweight aggregate kilns, and liquid fuel-fired boilers. 
Energy recovery units complying with this alternative would be required 
to collect three years of enumerated and nonenumerated semivolatile and 
low volatile metal nonhazardous waste fuel thermal feed concentration 
levels.\250\ Each source's allowable mass emission rate for this 
component would be equivalent to its associated three year average 
metal nonhazardous waste fuel thermal feed concentration for each metal 
group \251\ multiplied by: (1) One minus the MACT system removal 
efficiency for the specified metal group; and (2) its associated 
nonhazardous waste thermal feedrate.\252\ As discussed above, the MACT 
system removal efficiency that would be applied separately for 
semivolatile metals and low volatile metals would be determined as 
described in Part Two, Section VI.G.5 for each source category.
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    \250\ Sources would not be required to collect three years of 
data if the nonhazardous waste fuels such as natural gas do not 
contain metal HAP.
    \251\ Each source would be required to calculate its associated 
three year average metal concentrations in their coal for both 
semivolatile metals (lead, cadmium, and selenium) and low volatile 
metals (arsenic, beryllium, chromium, antimony, cobalt, manganese, 
and nickel) expressed in pounds per million Btu of coal.
    \252\ This would be equivalent to a kiln's coal feedrate 
expressed in million Btus per hour.
---------------------------------------------------------------------------

    e. Incinerators and Solid Fuel-Fired Boilers: Nonenumerated Metal 
HAP Emissions Attributable to Nonhazardous Waste Fuels. The fifth 
component limits nonenumerated semivolatile and low volatile metal mass 
emissions attributable to nonhazardous waste fuels (e.g., coal, fuel 
oil) and is applicable to incinerators and solid fuel-fired boilers. 
Sources complying with this alternative would be required to collect 
three years of nonenumerated semivolatile and low volatile metal 
nonhazardous waste fuel thermal feed concentrations. Each source's 
allowable mass emission rate for this component would be equivalent to 
its associated three year average metal nonhazardous waste fuel thermal 
feed concentration for each metal group \253\ multiplied by: (1) One 
minus the MACT system removal efficiency for the specified metal group; 
and (2) its associated nonhazardous waste fuel thermal feedrate 
(expressed as million btu per hour). As discussed above, the MACT 
system removal efficiency that would be applied separately for 
semivolatile metals and low volatile metals would be determined as 
described in Part Two, Section VI.G.5 for each source category.
---------------------------------------------------------------------------

    \253\ Each source would be required to calculate its associated 
three year average nonenumerated metal concentrations in their 
nonhazardous waste fuel for both semivolatile metals (selenium) and 
low volatile metals (antimony, cobalt, manganese, and nickel) 
expressed in pounds per million Btu.
---------------------------------------------------------------------------

    f. Incinerators and Solid Fuel-Fired Boilers: Nonenumerated Metal 
HAP Emissions Attributable to Nonfuel Nonhazardous Waste. The sixth 
component limits nonenumerated metal HAP emissions attributable to 
nonfuel nonhazardous waste feedstreams from incinerators and solid 
fuel-fired boilers. Sources complying with this alternative would be 
required to collect three years of nonenumerated semivolatile and low 
volatile metal nonfuel nonhazardous waste feedstream concentration 
data, expressed as mass of metal fed in its nonfuel nonhazardous waste 
feedstream per total thermal input into the combustor. Each source's 
allowable mass emission rate for this component would be equivalent to 
its associated three year average metal nonfuel nonhazardous waste 
thermal feed concentration for each metal group \254\ multiplied by: 
(1) One minus the MACT system removal efficiency for the specified 
metal group; and (2) its associated total thermal feedrate (expressed 
as million Btus per hour). As discussed above, the MACT system removal 
efficiency that would be applied separately for semivolatile metals and 
low volatile metals would be determined as described in Part Two, 
Section VI.G.5 for each source category.
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    \254\ Each source would be required to calculate its associated 
three year average nonenumerated metal thermal feed concentrations 
in their nonfuel nonhazardous waste feedstreams for both 
semivolatile metals (selenium) and low volatile metals (antimony, 
cobalt, manganese, and nickel) expressed in pounds per million Btu.
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    g. Cement Kilns and Lightweight Aggregate Kilns: Enumerated and 
Nonenumerated Metal HAP Emissions Attributable to Raw Materials. The

[[Page 21335]]

seventh component limits enumerated and nonenumerated metal HAP 
emissions attributable to raw material from cement kilns and 
lightweight aggregate kilns. Cement kilns and lightweight aggregate 
kilns complying with this alternative would be required to collect 
three years of enumerated and nonenumerated semivolatile and low 
volatile metal raw material feed concentration data, expressed as mass 
of metal fed in raw material per total thermal input into the 
kiln.\255\ Each cement kiln and lightweight aggregate kiln's allowable 
mass emission rate for this component would be equivalent to its 
associated three year average metal raw material thermal feed 
concentration for each metal group \256\ multiplied by: (1) one minus 
the MACT system removal efficiency for the specified metal group; and 
(2) its associated total thermal feedrate. As discussed above, the MACT 
system removal efficiency that would be applied separately for 
semivolatile metals and low volatile metals would be determined as 
described in Part Two, Section VI.G.5 for each source category.
---------------------------------------------------------------------------

    \255\ Total thermal input to kiln would include both hazardous 
and nonhazardous fuel thermal input.
    \256\ Each source would be required to calculate its associated 
three year average metal thermal feed concentrations in their raw 
material for both semivolatile metals (lead, cadmium, and selenium) 
and low volatile metals (arsenic, beryllium, chromium, antimony, 
cobalt, manganese, and nickel) expressed in pounds per million Btus.
---------------------------------------------------------------------------

2. Would Sources Still Be Required To Comply With a Particulate Matter 
Standard if They Comply With This Alternative?
    As previously discussed in Part Two, Section VI.F, we conclude that 
today's proposed floor levels can be no higher than the interim 
standards because all sources, not just the best performing sources, 
are achieving the interim standards. It is not clear whether this 
alternative total metal emission limitation is less stringent than the 
current interim particulate matter standard for incinerators, cement 
kilns, and lightweight aggregate kilns.\257\ As a result, incinerators, 
cement kilns, and lightweight aggregate kilns complying with this 
alternative would also be required to comply with the interim standard 
for particulate matter. Liquid and solid fuel-fired boilers complying 
with this alternative would remain subject to the RCRA particulate 
matter standard of 0.08 gr/dscf pursuant to Sec.  264.343(c).\258\
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    \257\ There is not a direct correlation between particulate 
matter emissions and metal emissions given that metal emission 
levels are both a function of feed control and particulate matter 
control.
    \258\ As previously discussed, this is because Clean Air Act 
standards can supplant RCRA standards only when the CAA standard is 
sufficiently protective of human health and the environment to make 
the RCRA standard duplicative (within the meaning of RCRA section 
1006 (b) (3)).
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3. How Would Sources Demonstrate Compliance With This Alternative?
    Sources complying with this alternative would be required to 
calculate its site-specific semivolatile and low volatile metal mass 
emission rate limitation as described above. Each source's emission 
limitation would not only be a function of its average three years of 
metal concentration data collected, but also would be a function of 
either its gas flowrate (for incinerators and solid fuel fired 
boilers), hazardous waste thermal firing rate (for cement kilns, 
lightweight aggregate kilns, and liquid fuel-fired boilers), and total 
thermal input rate (for all sources). As a result each source's mass 
emission limitation would vary over time as the dependent variables 
change (e.g., a cement kiln's allowable mass emission limitation would 
increase if its hazardous waste thermal firing rate increases).
    Sources would demonstrate compliance with these site-specific metal 
emission rate limitations during its comprehensive performance test and 
would establish operating parameter limits on its air pollution control 
device to ensure that the source achieves the metal system removal 
efficiency that was demonstrated during the test during normal day-to-
day operations. Sources would then establish total metal feedrate 
limits that would assure compliance with this site-specific metal 
emission limitation. Given that these metal emission limitations may 
vary over time, we request comment as to whether these emission 
limitations (and associated feedrate operating limits) should be 
instantaneous limits based on each source's current operating levels 
(e.g., hazardous waste thermal input rate for energy recovery units, or 
gas flowrate for incinerators), or rather 12 hour rolling average 
limits that would be updated each minute.

XIX. What Are the Proposed RCRA State Authorization and CAA Delegation 
Requirements?

A. What Is the Authority for This Rule?

    Today's rule amends the promulgated standards located at 40 CFR 
part 63, subpart EEE. It amends the standards for the Phase I source 
categories--incinerators, cement kilns, and lightweight aggregate kilns 
that burn hazardous waste, and it also amends subpart EEE to establish 
MACT standards for the Phase II source categories--boilers and 
hydrochloric acid production furnaces that burn hazardous waste. 
Additionally, this rule amends several RCRA regulations located in 40 
CFR part 270 to reflect changes in applicability, addition of a new 
permit modification procedure and additions related site-specific risk 
assessments and permitting.
1. How Is This Rule Delegated Under the CAA?
    Consistent with the September 1999 rule, we recommend that state, 
local, and tribal (S/L/T) air pollution control agencies apply for 
delegation of this subpart (and all NESHAP) under section 112(l) of the 
CAA, if they have not done so already, so that they can exercise 
delegable authorities for the final Phase I Replacement standards and 
Phase II standards. Delegable authorities are the discretionary 
activities, such as approving changes to the reporting schedule, that 
are part of each NESHAP. EPA retains some of those authorities, but 
allows most to be implemented by those S/L/T agencies who accept 
straight delegation of the NESHAP; in this case, subpart EEE. The 
delegable authorities, those that can and cannot be delegated, are 
described in section 63.1214 of this subpart. (For more information on 
delegation of part 63 provisions, see 65 FR 55810-55846.) All major 
sources of air pollutants, such as all sources subject to this subpart, 
must have a title V operating permit which would contain all applicable 
requirements, including those for this subpart. (For more information, 
please see 40 CFR part 70.) While S/L/T agencies can implement and 
enforce MACT standards through their approved title V programs, 
approval of title V programs alone do not allow S/L/T authorities to be 
the primary enforcement authority and they cannot exercise delegable 
provisions' authorities. An approved title V program means that S/L/T 
agencies commit to incorporating all MACT standards into title V 
permits as permit conditions and to enforcing all the terms and 
conditions of the permit.\259\ Having an approved title V program, for

[[Page 21336]]

instance, does not automatically allow S/L/T agencies to approve test 
plans, requests for (minor and intermediate) changes to monitoring, 
performance test waivers, document notifications, or other Category I 
Authorities (see 40 CFR 63.91(g)(1)(i)). For those S/L/T agencies who 
have been previously delegated authority for the MACT standards under 
40 CFR part 63 subpart EEE, we encourage you to request approval of the 
revisions to emission standards and various other compliance 
requirements of today's proposal when promulgated.
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    \259\ Accordingly, S/L/T agencies are required to reopen 
existing title V permits that have 3 or more years remaining in the 
permit term to include the promulgated standards. If there are less 
than 3 years remaining, S/L/T agencies may wait until renewal to 
incorporate the standards. Provided that a source is not required to 
reopen its title V permit, it must still fully comply with the 
promulgated standards (40 CFR 70.7(f)(1)(i)).
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B. Are There Any Changes to the CAA Delegation Requirements for Phase I 
Sources?

    With regard to CAA delegation requirements for Phase I sources, we 
intend to clarify which provisions in 40 CFR part 63 subpart EEE are 
delegable and those that are not in today's Notice of proposed 
rulemaking. We recently published a final rule, Clarifications to 
Existing National Emissions Standards for Hazardous Air Pollutants 
Delegations' Provisions on June 23, 2003 (see 68 FR 37334), that 
clarifies and streamlines delegable provisions for each existing 
NESHAP. Prior to finalization of this rule, many permitting authorities 
and sources alike were left to interpret which Category I authorities 
were delegable according to provisions specific to one NESHAP versus 
another. In light of this final rule, which outlines the non-delegable 
provisions for subpart EEE, some confusion remains today as to which 
actions can be taken by a delegated S/L/T agency. Therefore, we intend 
to clarify specific actions in subpart EEE that can or cannot be taken 
by permitting agencies who have received delegation under 112(l) of the 
CAA for subpart EEE.
    Sections 63.91(g)(1)(i) and (g)(2)(i) list authorities that are 
generally delegable to S/L/T agencies and those that are not, 
respectively. These apply to all NESHAP. Similar information contained 
in Sec.  63.1214 explains that some of the discretionary authorities, 
such as approval of alternative reporting schedules, under subpart EEE, 
can be implemented and enforced by a delegated authority. It also lists 
the authorities that are retained by EPA and are not delegable to S/L/T 
agencies even if they have received delegation for subpart EEE. These 
non-delegable authorities are: (1) Approval of alternatives to 
requirements in Sec. Sec.  63.1200, 63.1203 through 63.1205, and 
63.1206(a); (2) approval of major alternatives to test methods under 
Sec.  63.7(e)(2)(ii) and (f); (3) approval of major alternatives to 
monitoring under Sec.  63.8(f) and; (4) approval of major alternatives 
to recordkeeping and reporting under Sec.  63.10(f). It is important to 
note that if the alternatives mentioned in items (2) through (4) are 
determined to be minor or intermediate according to the definitions in 
Sec.  63.90(a), then they are considered delegable and can be approved 
by a S/L/T agency who has been granted authority for subpart EEE.\260\ 
To aid in the determination of whether a request is major, 
intermediate, or minor, we recommend that you consult the September 14, 
2000 final rule, Hazardous Air Pollutants: Amendments to the Approval 
of State Programs and Delegation of Federal Authorities (65 FR 55810). 
The preamble to this rule provides examples, as well as the regulatory 
definitions as they exist today in 40 CFR 63.90(a). Additionally, you 
may consult a guidance document entitled, How to Review and Issue Clean 
Air Act Applicability Determinations and Alternative Monitoring (EPA 
305-B-99-004, February 1999).
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    \260\ EPA Regions may choose whether they will or will not 
delegate authority to S/L/T agencies to approve minor and 
intermediate changes.
---------------------------------------------------------------------------

    While Sec.  63.1214(c) and Sec.  63.90(a) provide which authorities 
are not delegable for subpart EEE sources and define degrees of 
changes, they may not be clear in certain applications. We will address 
specific sections in subpart EEE, through the following preamble 
discussion and through regulatory amendments, where we believe there is 
a need for clarity based upon our experiences with the implementation 
of the Phase I standards thus far. Also, there are some alternatives in 
subpart EEE that were inadvertently left out of Sec.  63.1214(c) which 
we are adding through this Notice of proposed rulemaking.
    Beginning with test methods, major alternatives are not delegable. 
(See 40 CFR 63.90(a) for definitions of major, intermediate, and minor 
changes to test methods.) We noted in Sec.  63.1214(c)(2) that major 
alternatives to the test methods as addressed in the general provisions 
at Sec.  63.7(e)(2)(ii) and (f) were not delegable, however, we did not 
specifically include test methods relevant to subpart EEE. Section 
63.1208(b) specifies the test methods sources must use to determine 
compliance with emission standards in subpart EEE. This section is 
delegable in its entirety to S/L/T agencies who have been delegated 
authority for subpart EEE, as long as the request is not a major 
change. Additionally, the CEMS required in Sec.  63.1209(a)(1), 
although a monitoring requirement, is considered to be a test method 
since it serves as the benchmark measurement method for demonstrating 
compliance with emission standards. The authority to approve changes to 
the CEMS-related requirements is also delegable to S/L/T agencies as 
long as the request is not a major change. To summarize, if a source 
proposes a major change to a test method specified in Sec. Sec.  
63.1208(b) and 63.1209(a)(1), it must send the request to the 
appropriate EPA Region and EPA's Office of Air Quality Planning and 
Standards,\261\ since major changes to test methods are not delegable. 
We are adding Sec. Sec.  63.1208(b) and 63.1209(a)(1), to the 
authorities in Sec.  63.1214(c)(2) that are not delegable for major 
changes.
---------------------------------------------------------------------------

    \261\ Send requests to: Conniesue B. Oldham, Ph.D., Group 
Leader, Source Measurement Technology Group (D205-02), Office of Air 
Quality Planning and Standards, U.S. Environmental Protection 
Agency, Research Triangle Park, NC 27711.
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    Consistent with the major alternatives to test methods, major 
alternatives to monitoring are not delegable. (See 40 CFR 63.90(a) for 
definitions of major, intermediate, and minor changes to test methods.) 
We noted in Sec.  63.1214(c)(2) that major alternatives to monitoring 
as addressed in the general provisions in Sec.  63.8(f) were not 
delegable, but we did not specifically address the relevant monitoring 
requirements in subpart EEE. Section 63.1209 specifies the monitoring 
requirements sources must use to determine compliance with emission 
standards in EEE. Depending upon the pollutant to be monitored, either 
a CEMS or COMS is required.
    Before discussing whether changes to monitoring in subpart EEE are 
delegable, it is important first to review how requests for changes to 
monitoring are handled under the general provisions of Sec.  63.8(f). 
In general, requests for alternative monitoring follow the same 
approach, with respect to delegation authority, as requests for 
alternative test methods discussed above; requests that are defined as 
major should be sent to the appropriate EPA Region and requests that 
are intermediate or minor should be sent to the delegated S/L/T agency. 
A request to use other monitoring in lieu of a CEMS is always 
considered a major change. However, if a source proposes to use a CEMS 
in lieu of an operating parameter, the request may be considered an 
intermediate change, so long as the CEMS to be used is regarded as a 
``proven technology'' and could be submitted to a S/L/T agency for 
approval. The rationale for this is that the use of a CEMS, rather than 
monitoring via an operating parameter, provides a better measure of 
compliance

[[Page 21337]]

and thus, we want to encourage the use of CEMS when possible. While we 
want to encourage the use of CEMS, we recognize that S/L/T agencies may 
not always have the technical resources to review these applications, 
particularly when there are no federally promulgated performance 
specifications for the CEMS. In such cases, we expect that the S/L/T 
agency will rely on EPA Regions for approval.
    In subpart EEE, Sec.  63.1209, there are two alternative approaches 
to monitoring that sources may use. One is located at Sec.  
63.1209(a)(5), Petitions to use CEMS for other standards, and the other 
is at Sec.  63.1209(g)(1), Alternative monitoring requirements other 
than continuous emissions monitoring systems. Section 63.1209(a)(5) 
allows sources to request to use CEMS to monitor particulate matter, 
mercury, semivolatile metals, low volatile metals, and/or hydrochloric 
acid/chlorine gas in lieu of compliance with operating parameter 
limits. In these cases, a source would be monitoring the pollutant of 
concern and comparing the emissions measurements directly against an 
emission limitation rather than comparing the measurements to an 
operating parameter. We consider a request under Sec.  63.1209(a)(5) to 
be a major change to monitoring and consequently, it is not delegable. 
We classify Sec.  63.1209(a)(5) to be a major change (rather than an 
intermediate change which can be delegable) mainly because we have not 
yet promulgated Performance Specifications for the CEMS that may be 
used. In other words, it could be argued that these CEMS do not yet 
qualify as fully ``proven technology''. We understand that it could be 
argued either way, but for the reasons discussed in the previous 
paragraph and as an added measure of consistency, requests to use CEMS 
in lieu of operating parameters should be submitted to the EPA Region 
for approval. Therefore, we are adding Sec.  63.1209(a)(5) to the 
authorities in Sec.  63.1214(c)(2) that are not delegable for major 
changes.
    The other alternative monitoring provision, Sec.  63.1209(g)(1), 
allows sources to use alternative monitoring methods, with the 
exception of the standards that must be monitored with a CEMS, and to 
request a waiver of an operating parameter limit. Section 63.1209(g)(1) 
applies to requests for alternative parameter monitoring that involve 
the use of a different detector (i.e., thermocouple, pressure 
transducer, or flow meter), a different monitoring location, a 
different method as recommended by the manufacturer, or a different 
averaging period that is more stringent than the applicable standard. 
For example, sources equipped with wet scrubbers are required to 
establish a minimum pressure drop limit to assure adequate contact 
between the gas and liquid. A source may petition to have this 
monitoring requirement waived if the manufacturer does not recommend 
pressure drop as a critical control parameter that affects the unit's 
operating efficiency. Depending upon the type of wet scrubber, an 
appropriate minimum limit may be specified for steam injection rate, 
disk spin rate, or a maximum temperature limit on liquid and flue gas, 
rather than pressure drop. Also, sources could request more stringent 
averaging periods in order to ``mirror'' the averaging periods required 
under RCRA. This may facilitate an easier transition from RCRA to MACT 
during the time period sources may need to comply with both sets of 
requirements. Since we do not consider these changes to be major, 
requests under Sec.  63.1209(g)(1) should be sent to the delegated S/L/
T agency for approval. Accordingly, we are amending the language in 
Sec.  63.1209(g)(1) to specify that a source may submit an application 
to the Administrator or a State with an approved Title V program. Also, 
we are revising the title under Sec.  63.1209(g)(1) so that it is more 
specific regarding its intended use.
    Lastly, major alternatives to recordkeeping and reporting also are 
not delegable. (See 40 CFR 63.90(a) for definitions of major, 
intermediate, and minor changes to test methods.) We noted in Sec.  
63.1214(c)(2) that major alternatives to the general provisions of 
Sec.  63.10(f) were not delegable, but we did not specifically address 
any relevant recordkeeping and reporting requirements in subpart EEE. 
Section 63.1211 specifies the recordkeeping and reporting requirements 
sources must comply with in subpart EEE. This section is delegable in 
its entirety to S/L/T agencies who have been delegated authority to 
implement and enforce subpart EEE, as long as the request is not a 
major change. It is worthwhile to note that paragraph (e), Data 
compression, may be incorrectly interpreted as a major change itself to 
the recordkeeping and reporting requirements, because it appears as 
though there are no criteria to define fluctuation or data compression 
limits. However, this is not the case. In the preamble to the September 
1999 final rule (see 64 FR 52961 and 52962), we provided guidance for 
preparing a request to use data compression techniques and recommended 
fluctuation and data compression limits. This guidance was not affected 
by the court's vacatur of portions of this rule, so it remains in 
effect. Consequently, this allows permitting authorities to be 
consistent in their evaluation of requests. We view paragraph (e) to be 
a minor change itself and so a written request to use data compression 
techniques can be submitted to a delegated S/L/T agency. We are adding 
Sec.  63.1211(a)--(d) to the authorities in Sec.  63.1214(c)(2) that 
are not delegable for major changes.
    In addition to the clarifications and amendments addressed above, 
there are two important delegation issues we would like to emphasize. 
The first is simply to remind sources and permitting authorities alike 
that, if a provision in this subpart specifies that you may petition or 
request that the ``Administrator or State with an approved Title V 
program * * *,'' then a state that has not been delegated for that 
requirement, but has an approved Title V program, does have the 
authority to approve or disapprove the request. For instance, Sec.  
63.6(i)(1) and Sec.  63.1213(a) both specify that the ``Administrator 
(or a State with an approved permit program)'' can grant a compliance 
extension request. The second is that EPA Regions can decide whether or 
not to delegate the authority to approve intermediate changes to state 
and local agencies. In some cases, a state may have received delegation 
to approve only minor changes. Where there is uncertainty, we recommend 
that sources try to determine if a request is major, intermediate, or 
minor based on the definitions in 40 CFR 63.90(a), and then consult 
with their S/L/T agency and/or EPA Region to determine where to submit 
the request. Or, sources may submit requests to the S/L/T agency or EPA 
Region who will then determine where it should go for approval.

C. What Are the Proposed CAA Delegation Requirements for Phase II 
Sources?

    With respect to CAA delegation requirements for Phase II sources, 
they are the same as those for Phase I sources. Since both Phase I and 
Phase II MACT standards are located in the same subpart, EEE, the same 
delegation provisions apply to both. Generally speaking, authority to 
approve alternatives to standards or major changes to test methods, 
monitoring, and recordkeeping and reporting are not delegated to S/L/T 
agencies. Authority to approve intermediate and minor changes to test 
methods, monitoring, and recordkeeping and reporting are delegated to 
S/L/T agencies who have been delegated authority to implement

[[Page 21338]]

subpart EEE. All other subpart EEE implementation requirements may be 
handled by the delegated S/L/T agency. For specific information, please 
refer to the previous section, A.1. What are the clarifications and 
changes to CAA delegable authorities for this rule?
    How Would States Become Authorized under RCRA for this Rule? Under 
section 3006 of RCRA, EPA may authorize qualified states to administer 
their own hazardous waste programs in lieu of the federal program 
within the state. Following authorization, EPA retains enforcement 
authority under sections 3008, 3013, and 7003 of RCRA, although 
authorized states have primary enforcement responsibility. The 
standards and requirements for state authorization are found at 40 CFR 
part 271.
    Prior to enactment of the Hazardous and Solid Waste Amendments of 
1984 (HSWA), a State with final RCRA authorization administered its 
hazardous waste program entirely in lieu of EPA administering the 
federal program in that state. The federal requirements no longer 
applied in the authorized state, and EPA could not issue permits for 
any facilities in that state, since only the state was authorized to 
issue RCRA permits. When new, more stringent federal requirements were 
promulgated, the state was obligated to enact equivalent authorities 
within specified time frames. However, the new federal requirements did 
not take effect in an authorized state until the state adopted the 
federal requirements as state law.
    In contrast, under RCRA section 3006(g) (42 U.S.C. 6926(g)), which 
was added by HSWA, new requirements and prohibitions imposed under HSWA 
authority take effect in authorized states at the same time that they 
take effect in unauthorized states. EPA is directed by the statute to 
implement these requirements and prohibitions in authorized states, 
including the issuance of permits, until the state is granted 
authorization to do so. While states must still adopt HSWA related 
provisions as state law to retain final authorization, EPA implements 
the HSWA provisions in authorized states until the states do so.
    Authorized states are required to modify their programs only when 
EPA enacts federal requirements that are more stringent or broader in 
scope than existing federal requirements. RCRA section 3009 allows the 
states to impose standards more stringent than those in the federal 
program (see also 40 CFR 271.1). Therefore, authorized states may, but 
are not required to, adopt federal regulations, both HSWA and non-HSWA, 
that are considered less stringent than previous federal regulations.
    The amendments to the RCRA regulations proposed today in sections 
40 CFR 270.10, 270.22, 270.32, 270.42, 270.66, and 270.235 are 
considered to be either less stringent or equivalent to the existing 
Federal program. Thus, states are not required to modify their programs 
to adopt and seek authorization for these provisions, although we 
strongly encourage them to do so to facilitate the transition from the 
RCRA program to the CAA program and to promote national consistency. 
Additionally, 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.
    The amendments in sections 40 CFR 270.22 and 270.66 in today's 
notice are proposed under the HSWA amendments to RCRA. Further, today's 
proposed amendment in 40 CFR 270.235 to apply this provision to solid 
and liquid fuel-fired boilers and HCL production furnaces, is proposed 
under HSWA statutory authority. The amendments to the RCRA regulations 
proposed today in sections 40 CFR 270.10 and 270.32 are proposed under 
both non-HSWA and HSWA authority, depending on the type of unit to 
which these amendments are applied (under HSWA authority if applied to 
BIFs or non-HSWA authority if applied to incinerators). Refer to Part 
Two, Section XVII.D.4 for a more detailed discussion of the 
implementing authorities for proposed regulations in 40 CFR 270.10 and 
270.32. The following RCRA sections, enacted as part of HSWA, apply to 
today's rule: 3004(o), 3004(q), and 3005(c)(3). 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 271.1(j), which identifies rulemakings that 
are promulgated pursuant to HSWA.

Part Three: Proposed Revisions to Compliance Requirements

    In this section, we discuss proposed revisions to compliance 
requirements that may affect all hazardous waste combustors. We also 
request comment on whether we should make revisions to other compliance 
requirements, and explain why we conclude not to make revisions to 
other compliance requirements that we proposed (or requested comment 
on) previously.

I. Why Is EPA Proposing To Allow Phase I Sources To Conduct the Initial 
Performance Test To Comply With the Replacement Rules 12 Months After 
the Compliance Date?

    We propose to allow owners and operators of incinerators, cement 
kilns, and lightweight aggregate kilns to commence the initial 
comprehensive performance test to comply with the replacement standards 
proposed at Sec. Sec.  63.1219, 63.1220, and 63.1221 within 12 months 
of the compliance date rather than within six months of the compliance 
date. See proposed Sec.  63.1207(c)(3). Owners and operators of solid 
fuel-fired boilers, liquid fuel-fired boilers, and hydrochloric acid 
production furnaces, however, must commence the initial comprehensive 
performance test within six months of the compliance date.
    During development of the joint motion by petitioners to the United 
States Court of Appeals for the District of Columbia Circuit that 
resulted in the Agency promulgating the Interim Standards Rule on 
February 13, 2002,\262\ stakeholders representing owners and operators 
of incinerators, cement kilns, and lightweight aggregate kilns 
requested that we propose to allow them 12 months after the compliance 
date to commence the initial comprehensive performance test. These 
stakeholders request a 12 month window rather than the six month window 
currently required under Sec.  63.1207(c) to give them longer to 
amortize the cost of the comprehensive performance test demonstrating 
compliance with the Interim Standards before having to retest to 
demonstrate compliance with the replacement standards proposed 
today.\263\ We believe this request has merit and so are proposing to 
allow them to commence the initial comprehensive performance test 
within 12 months after the compliance date.\264\
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    \262\ See discussion in Part One, Section I.B.1.
    \263\ These stakeholders assumed, correctly, that today's 
proposed replacement emission standards would be substantially more 
stringent than the current (September 1999 Final Rule) standards.
    \264\ Please note that this does not affect the compliance date. 
You must be in compliance with the replacement standards on the 
compliance date, and certify in the Documentation of Compliance that 
you have established operating parameter limits that you believe 
will ensure compliance with the standards. You must record the 
Documentation of Compliance in the operating record by the 
compliance date.

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[[Page 21339]]

II. Why Is EPA Requesting Comment on Requirements Promulgated as 
Interim Standards or as Final Amendments?

    As discussed in Part One, Section I.B., EPA promulgated interim 
standards (called the Interim Standards Rule) on February 13, 2002 that 
amended compliance and implementation provisions of the September 1999 
Final Rule. The amended provisions were specified in a joint motion by 
petitioners to the United States Court of Appeals for the District of 
Columbia Circuit (the Court). Although petitioners agreed that the 
amendments should be promulgated (see 67 FR at 6794), petitioners 
requested that EPA reopen certain amended provisions for public 
comment.
    Also as discussed in Part One, Section I.B, EPA promulgated 
amendments (called Final Amendments) to the September 1999 Final Rule 
on February 14, 2002 that revised certain implementation and compliance 
requirements. These amendments were also specified in the joint motion 
to the Court, and petitioners requested that EPA reopen specific 
amended provisions for public comment.
    We discuss these provisions in this section, and reopen them for 
public comment. (We note, however, that we are not reopening for 
comment any RCRA rules, and are not soliciting comment on any aspect of 
those rules, or otherwise reconsidering or reexaming any such rules. 
Any references to RCRA rules in the discussion which follows is solely 
as an aid to readers.) Although we are not proposing additional 
revisions to these provisions, we may determine after review of public 
comments on the issues we raise that revisions are appropriate. If so, 
we would promulgate those amendments in the Replacement Rule.
    Although these provisions currently apply only to incinerators, 
cement kilns, and lightweight aggregate kilns, we are proposing today 
to apply them to boilers and hydrochloric acid production furnaces as 
well. (See Part Two, Sections XIII-XV.) Accordingly, any amendments to 
these requirements that we may promulgate would also apply to boilers 
and hydrochloric acid production furnaces.

A. Interim Standards Amendments to the Startup, Shutdown, and 
Malfunction Plan Requirements

    The September 1999 Final Rule required compliance with the emission 
standards and operating requirements at all times that hazardous waste 
is in the combustion system, including during startup, shutdown, and 
malfunctions. Industry stakeholders noted that requiring compliance 
with emission standards and operating requirements during startup, 
shutdown, and malfunctions is inconsistent with the General Provisions 
of subpart A, part 63, that apply to MACT sources (unless alternative 
requirements are prescribed for a source category). Stakeholders stated 
that it is inappropriate to penalize a source for exceeding emission 
standards and operating requirements during malfunctions because some 
exceedances are unavoidable and sources are already required to take 
corrective measures prescribed in the startup, shutdown, and 
malfunction plan (SSMP) to minimize emissions.
    In response to industry stakeholder concerns, the Interim Standards 
Rule amended the SSMP requirements to: (1) Exempt sources from the 
Subpart EEE emission standards and operating requirements during 
startup, shutdown, and malfunctions; (2) continue to subject sources to 
RCRA requirements during malfunctions, unless they comply with 
alternative MACT requirements including expanding the SSMP to minimize 
the frequency and severity of malfunctions, and submit the plan to the 
delegated CAA authority for review and approval \265\; (3) continue to 
subject sources that burn hazardous waste during startup and shutdown 
to RCRA requirements for startup and shutdown, unless they comply with 
alternative MACT requirements, and require sources to include waste 
feed restrictions and operating conditions and limits in the startup, 
shutdown, and malfunction plan; (4) require sources to include in the 
SSMP a requirement to comply with the automatic hazardous waste feed 
cutoff system during startup, shutdown, and malfunctions; and (5) make 
conforming revisions to the emergency safety vent opening requirements. 
See 67 FR at 6798-6802.
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    \265\ These requirements are needed to minimize emissions of HAP 
during startup, shutdown, and malfunctions and, thus, help meet our 
RCRA mandate to ensure that emissions from hazardous waste 
combustors do not pose a hazard to human health and the environment. 
Sources may elect either to remain under RCRA control during these 
events or to comply under MACT with requirements to develop and 
implement a comprehensive and proactive startup, shutdown, and 
malfunction plan that is reviewed and approved by the delegated 
regulatory authority.
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    In response to Sierra Club's request during development of the 
joint motion to the Court, we specifically request comment on the 
following issues. Notwithstanding the rationale for revising the 
September 1999 Final Rule to exempt sources from the subpart EEE 
emission standards and operating requirements during malfunctions, 
would it be appropriate to require compliance with those standards and 
operating requirements during malfunctions to ensure that owners and 
operators have an incentive to minimize the frequency and duration of 
malfunctions that result in exceedances of the standards or operating 
requirements. Given that most excess emissions would occur during 
startup, shutdown, and malfunctions, should the SSMP be submitted for 
review by the delegated regulatory authority and made available for 
public review under all options for controlling emissions during 
startup, shutdown, and malfunctions? Providing a mechanism for public 
review may help ensure that the SSMP is complete, proactive, and 
provides appropriate corrective measures.\266\ And finally, should the 
final rule clarify the definitions of startup, shutdown, and 
malfunctions to preclude, for example, an owner or operator incorrectly 
classifying an exceedance of an operating limit while hazardous waste 
remains in the combustion chamber as a malfunction when, in fact, the 
exceedance occurred because of a not infrequent event that could have 
been prevented by proper operation and maintenance of equipment?
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    \266\ We also request comment on whether the startup, shutdown, 
and malfunction plan should be expanded beyond the scope required 
under Sec.  63.6(e)(3) (requiring appropriate corrective measures in 
reaction to a malfunction) to address specific, proactive measures 
that the owner and operator have considered and are taking to 
minimize the frequency and severity of malfunctions.
---------------------------------------------------------------------------

B. Interim Standards Amendments to the Compliance Requirements for 
Ionizing Wet Scrubbers

    The September 1999 Final Rule required sources to establish a limit 
on minimum total power to an ionizing wet scrubber. The Interim 
Standards Rule deleted that requirement to conform with the 
requirements for electrostatic precipitators given that an ionizing wet 
scrubber is essentially an ESP integrated with a packed bed scrubber. 
See 67 FR at 6802-03.\267\ In lieu of establishing a limit on the 
minimum total power requirement to an ionizing wet scrubber, sources 
and delegated CAA authorities will use the alternative monitoring 
provisions of Sec.  63.1209(g) to identify appropriate controls for an 
ionizing wet scrubber on a site-specific basis. This is

[[Page 21340]]

the same approach that is used for electrostatic precipitators.
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    \267\ EPA voluntarily vacated operating parameter limits for 
electrostatic precipitators (and fabric filters) on May 14, 2001. 
See 66 FR at 24272. Until new operating parameter limits are 
promulgated, sources and delegated CAA authorities will use Sec.  
63.1209(g) to establish operating parameter limits for electrostatic 
precipitators (and fabric filters) on a site-specific basis.
---------------------------------------------------------------------------

    Please note that we are requesting comment today on compliance 
requirements for electrostatic precipitators and fabric filters. In 
that discussion (see Section III.I below), we explain that we are 
proposing to apply the same compliance requirements to both 
electrostatic precipitators and ionizing wet scrubbers.

C. Why Is EPA Requesting Comment on the Fugitive Emission Requirements?

    The September 1999 Final Rule required sources to control 
combustion system leaks by either: (1) Keeping the combustion zone 
sealed; (2) maintaining the maximum combustion zone pressure lower than 
ambient pressure using an instantaneous monitor; or (3) using an 
alternative means to provide control of system leaks equivalent to 
maintaining the maximum combustion zone pressure lower than ambient. 
After publication of the September 1999 Final Rule, stakeholders 
expressed concern that the option to maintain combustion zone pressure 
lower than ambient pressure (option 2 above) could result in overly 
prescriptive requirements. Stakeholders believed that this regulatory 
language could be interpreted to require sources to monitor and record 
combustion zone pressure at a frequency of every 50 milliseconds. 
Stakeholders also requested that we clarify that combustion system 
leaks refers to fugitive emissions resulting from the combustion of 
hazardous waste, and not fugitive emissions that originate from 
nonhazardous process streams.
    In response to these concerns, we proposed amendments to the 
combustion system leak provisions on July 3, 2001. See 66 FR at 35132. 
We promulgated several revisions in the Final Amendments Rule after 
considering stakeholder comments. See 67 FR at 6973.
    The amended provisions that we are reopening for public comment 
today are discussed below. First, we amended the definition of an 
instantaneous pressure monitor to better clarify that the intent of the 
combustion system leak requirements is to prevent fugitive emissions 
from the combustion of hazardous waste rather than from nonhazardous 
feedstreams. The revised definition also clarifies that instantaneous 
pressure monitors must detect and record pressure at a frequency 
adequate to detect combustion system leak events, as determined on a 
site-specific basis. See Sec.  63.1201(a) and Sec.  63.1209(p). Second, 
we added a provision that requires sources to specify the method used 
to control combustion system leaks in the performance test workplan and 
Notification of Compliance. See Sec.  63.1206(c)(5)(ii). Finally, in 
response to numerous comments, we added a provision that will allow 
sources, upon prior written approval of the Administrator, to use other 
techniques that can be demonstrated to prevent fugitive emissions 
without the use of instantaneous pressure limits. See Sec.  
63.1206(c)(5)(i)(D).
    The provision allowing sources, upon prior written approval, to use 
other techniques that are demonstrated to prevent fugitive emissions 
without the use of instantaneous pressure limits was the most 
controversial. Specifically, some stakeholders believe this revised 
regulatory language is inappropriate because it suggests sources can 
sustain a positive pressure event and still prevent fugitive emissions. 
We believe that all positive pressure events do not necessarily result 
in fugitive emissions. As discussed in detail in the Final Amendments 
Rule, there are state-of-the-art rotary kiln seal designs (such as 
shrouded and pressurized seals) which are capable of handling positive 
pressures without fugitive releases. However, we believe these kilns 
are highly unusual, and that other conventional rotary kilns used in 
the hazardous waste combustion industry may not have seals which are 
designed for such positive pressure operation. In fact, we believe 
that, for most rotary kilns in use today, positive pressure events can 
result in fugitive releases. The level of such fugitive releases will 
be dependent on factors including the magnitude and duration of the 
pressure excursion and the design and operation of the kiln.
    Furthermore, one commenter recommends that sources should be 
allowed to petition the regulatory official to use an alternative 
approach, i.e., an approach that does not require instantaneous 
pressure limits, only if they meet specific combustor design criteria. 
For example, it may be appropriate to apply this provision only to 
sources that we know are designed in manner that would not necessitate 
use of instantaneous pressure limits to prevent fugitive emissions 
(e.g., kilns with multiple graphite seals with pressurized chambers 
between the seals to prevent out-leakage, or overlapping spring plate 
seals to form an air seal). We request comment on whether this 
specificity is necessary, or whether it is more appropriate to 
determine this on a site-specific basis (as is currently required). We 
also request comment on whether all the previously discussed combustion 
system leak regulatory revisions are appropriate.

D. Why Is EPA Requesting Comment on Bag Leak Detector Sensitivity?

    The September 1999 Final Rule required sources equipped with fabric 
filters to install a bag leak detection system where the detector has 
the capability to detect PM emissions at concentrations of 1.0 
milligrams per actual cubic meter, or less. In response to industry 
stakeholder concerns that a detector need not be able to detect levels 
as low as 1.0 mg/acfm to detect subtle changes in baseline, normal 
emissions of PM, we proposed in the July 3, 2001, proposed rule (66 FR 
at 35134-35) to allow sources to use detectors with less sensitivity 
provided that the detector could detect subtle increases in normal 
emissions (e.g., caused by pinhole leaks in the bags). The stakeholders 
noted that sources equipped with well designed and operated fabric 
filters can have normal, baseline emissions well above 1.0 mg/acfm and 
be in compliance with the particulate matter emission standards. 
Stakeholders recommended that we revise the bag leak detection 
requirements to explicitly allow detectors with lower sensitivity in 
lieu of source's having to petition the delegated regulatory authority 
under the alternative monitoring provisions of Sec.  63.1209(g)(1) to 
receive case-by-case approval. All commenters on the proposed amendment 
supported the revision, and we finalized the amendment in the February 
14, 2002, Final Amendments. See 67 FR at 6981.
    In response to a petitioner's request during development of the 
joint motion to the Court, however, we specifically request additional 
comment on whether allowing detectors that have a level of detection 
that is higher than 1.0 mg/acfm will enable the detector to detect 
subtle increases in normal emissions. The petitioner is concerned that 
a detector with a level of detection higher than 1.0 mg/acfm may not 
have the same sensitivity as a detector that can detect PM at 1.0 mg/
acfm. Thus, petitioner is concerned that the less sensitive detector 
may not be able to detect subtle increases in PM emissions due to bag 
degredation as readily as a detector that can detect at 1.0 mg/acfm. We 
specifically request comment on this issue.
    We reopen this issue for comment without prejudice to the existing 
regulations which allow for less sensitive bag leak detectors. You may 
use less sensitive bag leak detectors until the compliance date for any 
change we may make in the final rule.

[[Page 21341]]

E. Final Amendments Waiving Operating Parameter Limits During Testing 
Without an Approved Test Plan

    The September 1999 Final Rule waived operating parameter limits 
during subsequent performance testing under an approved performance 
test plan. In response to stakeholder concerns, we addressed two issues 
in the Final Amendments: (1) Applicability of operating parameter 
limits, established in the Documentation of Compliance, during an 
initial performance test conducted without an approved test plan; and 
(2) applicability of operating parameter limits, established in the 
Notification of Compliance, during subsequent performance tests 
conducted without an approved test plan. See 67 FR at 6978.
    Regarding the initial performance test, we explained that a source 
can revise the operating parameter limits specified in the 
Documentation of Compliance at any time based on supporting 
information. This information would also be included in the performance 
test plan to support deviating from the operating limits established in 
the previous Documentation of Compliance. Given that sources operate 
after the compliance date until the Notification of Compliance is 
submitted under operating limits established in the Documentation of 
Compliance, and that the technical support for the operating limits 
established in the Documentation of Compliance is the same as would be 
included in the test plan, it is appropriate to allow initial 
performance testing and associated pretesting without an approved test 
plan.
    Regarding subsequent performance testing, we amended the rule to 
waive the operating parameter limits during performance testing and 
associated pretesting even when testing without an approved test plan. 
We reasoned that stack emissions data obtained during the testing would 
document whether the source maintained compliance with the emission 
standards. (Please note that during testing, including pretesting, 
stack emissions must be documented for any emissions standard for which 
the source waives an operating parameter limit.) Absent approval of the 
test plan, documentation of potential violation of an emission standard 
is nonetheless an ample incentive to operate within the emission 
standards.
    In response to a petitioner's request during development of the 
joint motion to the Court, however, we request comment on whether 
documentation of stack emissions during subsequent performance testing 
and associated pretesting is adequate to ensure compliance with the 
emission standards absent an approved test plan.

III. Why Is EPA Requesting Comment on Issues and Amendments That Were 
Previously Proposed?

    In a July 3, 2001, proposed rule, EPA proposed several revisions to 
implementation and compliance requirements, and discussed other 
implementation and compliance issues. See 66 FR 35126. We promulgated 
several of those amendments in the February 14, 2002, Final Amendments 
Rule, and we stated in that rule that we would address the remaining 
proposed amendments and other issues in a future rulemaking. See 67 FR 
at 6970-71. We discuss below those remaining proposed amendments and 
issues.
    Although these issues and proposed amendments originally pertained 
only to incinerators, cement kilns, and lightweight aggregate kilns, 
any amendments that we may promulgate subsequent to this notice would 
also apply to boilers and hydrochloric acid production furnaces.

A. Definition of Research, Development, and Demonstration Source.

    In response to industry stakeholder concerns, EPA requested comment 
in the July 3, 2001, proposed rule on approaches to preclude 
inappropriate use of the exemption for research, development, and 
demonstration sources. See 66 FR at 35128. We indicated we were 
considering two approaches: (1) Clearly distinguishing between research 
and development sources, and limiting the exemption for demonstration 
sources to one year or less; or (2) requiring documentation of how a 
source's demonstration of an innovative or experimental hazardous waste 
treatment technology or process is different from the waste management 
services provided by a commercial hazardous waste combustor.
    Two stakeholders provided comments, and both recommended that EPA 
not revise the definition of research, development, and demonstration 
source. One commenter suggested that EPA should be able to determine if 
a source is inappropriately claiming the exemption for research, 
development, and demonstration source without amending the regulation. 
The other commenter suggested that, rather than amend the regulation, 
EPA should reiterate that RCRA regulations continue to apply to exempt 
research, development, and demonstration sources.\268\
---------------------------------------------------------------------------

    \268\ 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.
---------------------------------------------------------------------------

    We concur with the commenters and are not proposing to amend the 
definition of research, development, and demonstration source.

B. Identification of an Organics Residence Time That Is Independent of, 
and Shorter Than, the Hazardous Waste Residence Time

    In response to industry stakeholder recommendations, EPA requested 
comment in the July 3, 2001, proposed rule on whether it is practicable 
to calculate a hazardous waste organics residence time that defines 
when organic constituents in solid materials have been destroyed. See 
66 FR at 35128-30. Under stakeholders' recommendation, after the 
hazardous waste organics residence time expires, sources could comply 
with standards the Agency has promulgated under sections 112 or 129 of 
the Clean Air Act to control organic emissions for source categories 
that do not burn hazardous waste in lieu of the hazardous waste 
combustor standards and associated compliance requirements under 
subpart EEE, part 63, for dioxin/furan, destruction and removal 
efficiency, and carbon monoxide or hydrocarbon emissions.\269\
---------------------------------------------------------------------------

    \269\ Stakeholders also wanted the hazardous waste residence 
time (for organics) to expire as soon as possible to avoid 
violations associated with exceedances of an organics emission 
standard or associated operating requirement during malfunctions 
when hazardous waste remained in the combustion chamber. The rule 
has been amended, however, to state that an exceedance of an 
emission standard or operating requirement during a malfuncation is 
not a violation provided that the source has developed an 
appropriate startup, shutdown, and malfuncation plan, and follows 
the corrective measures provided by the plan. See 67 FR at 6798-
6801.
---------------------------------------------------------------------------

    In the July 3, 2001, proposed rule, we raised several concerns 
regarding the approach recommended by stakeholders to calculate an 
organics residence time, and specifically requested comment on how 
these concerns could be addressed. See 66 FR at 35130. Although several 
stakeholders provided comment on the discussion we presented in the 
July 3, 2001, proposed rule, commenters did not address the concerns we 
raised. Rather, commenters generally note that calculation of an 
organics residence time for solid waste streams would be difficult to 
characterize generically. Accordingly, commenters suggest that the rule 
be amended to specifically allow calculation of an organics residence 
time on a site-specific basis.
    We are reluctant to encourage site-specific petitions to calculate 
an

[[Page 21342]]

organics residence time, however, given that the concerns we raised in 
the July 3, 2001, proposal have not been addressed.\270\ Moreover, we 
believe that stakeholders' primary motive for identifying an organics 
residence time has been eliminated by the February 13, 2002, amendment 
to the rule stating that an exceedance of an emission standard or 
operating requirement during a malfunction when hazardous waste remains 
in the combustion chamber is not a violation provided that the source 
follows the corrective measures provided by an appropriate startup, 
shutdown, and malfunction plan.
---------------------------------------------------------------------------

    \270\ We questioned whether available information on low oxygen 
destruction would adequately model destruction under the pyrolytic 
conditions that occur within solid matrices and whether it is 
practicable to perform valid engineering calculations for multiple 
waste streams that are not homogeneous and that contain multiple 
organic constituents of concern.
---------------------------------------------------------------------------

    For these reasons, we are not proposing an organics residence time 
or explicitly encouraging sources to petition the delegated CAA 
authority on a site-specific basis to identify an organics residence 
time.

C. Why Is EPA Not Proposing To Extend APCD Controls After the Residence 
Time Has Expired When Sources Operate Under Alternative Section 112 or 
129 Standards?

    In the July 3, 2001, proposed rule, we proposed to extend 
applicability of operating requirements for dry particulate matter 
emission control devices before you could switch modes of operation and 
become subject to Section 112 or 129 standards for sources that do not 
burn hazardous waste. See 66 FR at 35130-32. We proposed to require you 
to maintain compliance with applicable emission standards for 
semivolatile metals, low volatile metals, and particulate matter, 
including the operating parameter limits for dry control systems, after 
the hazardous waste residence time has expired until the control device 
undergoes a complete cleaning cycle. We were concerned that dry 
particulate matter control devices such as electrostatic precipitators 
and baghouses retain collected particulate matter contaminated with 
waste-derived metals; and dioxin/furan when activated carbon injection 
is used. In such cases, we were concerned that waste-derived metals and 
dioxin/furan may be emitted at levels exceeding the hazardous waste 
combustor emission standards if you were to switch modes of operation 
and comply with potentially less stringent alternative MACT standards 
for sources that do not burn hazardous waste (e.g., subpart LLL for 
cement kilns, section 129 standards the Agency is developing for 
commercial and industrial solid waste incinerators, and MACT standards 
the Agency is developing for boilers).\271\
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    \271\ Please note that you are subject to the standards under 
subpart EEE at all times, including after the hazardous waste 
residence time has expired, unless you have established an 
alternative mode of operation under Sec.  63.1209(q)(1).
---------------------------------------------------------------------------

    Commenters raised several concerns about the practicability of 
maintaining compliance with the semivolatile metals, low volatile 
metals, and particulate matter standards after the hazardous waste 
residence time has expired until the particulate matter device 
undergoes a complete cleaning cycle. Commenters explained that it is 
difficult to determine when a cleaning cycle has been completed for 
multi-field electrostatic precipitators and multi-compartment fabric 
filters because fabric filter cleaning is typically a continuous 
process, and electrostatic precipitator plate cleaning frequency varies 
significantly depending on the plate position within the electrostatic 
precipitator. Commenters also stated that the proposed requirement 
would encourage more frequent cleaning of electrostatic precipitators 
and fabric filters than normal, which could increase emissions of HAP 
and adversely affect bag life.
    After review of comments and further consideration, we conclude 
that it is not necessary to revise the standards to extend 
applicability of the operating requirements for dry particulate matter 
control devices before you could switch modes of operation and become 
subject to MACT standards for sources that do not burn hazardous waste. 
We now believe that it is highly unlikely that entrained particulate 
matter contaminated with hazardous waste derived metals would be 
released from the electrostatic precipitator or fabric filter at rates 
higher than when feeding hazardous waste when the source begins 
operating under the alternative MACT (or section 129) standards for 
sources that do not burn hazardous waste. In addition, incinerators, 
cement kilns, and solid-fuel-fired boilers would be subject to 
alternative standards and operating limits for particulate matter. 
Although lightweight aggregate kilns would not be subject to 
alternative standards for particulate matter,\272\ lightweight 
aggregate kilns that burn hazardous waste are equipped with fabric 
filters where their performance is not highly sensitive to operating 
conditions. And, although liquid fuel-fired boilers would not be 
subject to alternative Section 129 standards for particulate 
matter,\273\ over 80% of liquid fuel-fired boilers that burn hazardous 
waste are not equipped with a control device, and only about one third 
of those with a control device are equipped with an electrostatic 
precipitator or fabric filter. Thus, the absence of particulate matter 
controls under the alternative section 129 standards is not a 
significant concern.
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    \272\ The Agency determined that lightweight aggregate kilns 
that do not burn hazardous waste are not a significant source of HAP 
emissions and, thus, that MACT standards are not necessary for that 
source category.
    \273\ The Agency did not propose PM standards for existing 
liquid fuel-fired industrial, commercial, and institutional boilers 
and process heaters. See 68 FR 1660.
---------------------------------------------------------------------------

    For these reasons, we are not proposing to extend applicability of 
the operating requirements for dry particulate matter control devices 
before you could switch modes of operation and become subject to MACT 
standards for sources that do not burn hazardous waste.

D. Why Is EPA Proposing To Allow Use of Method 23 as an Alternative to 
Method 0023A for Dioxin/Furan?

    The September 1999 Final Rule requires use of Method 0023A for 
stack sampling of dioxin/furan emissions. In response to industry 
stakeholder requests, we proposed in the July 3, 2001, proposed rule to 
allow you to petition the delegated regulatory authority to use Method 
23 found in 40 CFR part 60, appendix A, instead of Method 0023A. See 66 
FR at 35137. We are revising the proposal today to allow you to use 
Method 23 in lieu of Method 0023A after justifying use of Method 23 as 
part of your performance test plan that must be reviewed and approved 
by the delegated regulatory authority. See proposed Sec.  
63.1208(b)(1)(i)(B). This approach would achieve the same objectives as 
a petition, but would be simpler to implement because it would not 
require a separate petition/document.
    In the July 3, 2001, proposed rule, we explain that Method 0023A is 
an improved version of Method 23 in that it can improve the quality 
assurance of the method. By analyzing the sampling train front half 
catch (filter and probe rinse) separately from the back half catch 
(sorbent and rinses), Method 0023A provides quality assurance of 
recovery of dioxin/furan contained in solid phase particulate and 
collected on the filter and probe. Under Method 23, poor recovery of 
dioxin/furan contained in solid phase particulate may go unnoticed 
because the front half catch and back half catch are combined before 
analysis. This may be of particular

[[Page 21343]]

importance for sources that use activated carbon injection or sources 
that have carbonaceous material in particulate matter.
    Although Method 0023A can improve quality assurance, it is slightly 
more expensive than Method 23 and, in many situations, quality 
assurance may not be improved. For example, Method 0023A may not be 
warranted in the future if Method 0023A analyses document that dioxin/
furan are not detected, are detected at low levels in the front half of 
Method 0023A, or are detected at levels well below the emission 
standard, and the design and operation of the combustor has not changed 
in a manner that could increase dioxin/furan emissions.
    Environmental stakeholders comment that use of Method 23 would 
allow sources to emit dioxin/furan in excess of the standards without 
being detected. We disagree. Owners and operators seeking to use Method 
0023A would be required to document using data or information that 
Method 23 would provide front half recoveries comparable to Method 
0023A.
    Industry stakeholders comment that we should simply revise the rule 
to allow use of either method, rather than requiring a petitioning 
process to use Method 23. As discussed above (and in the July 3, 2001, 
proposal), we believe that there are situations where the quality 
assurance and added cost of Method 0023A may be warranted, and, so, are 
not proposing to allow use of Method 23 without justification and prior 
approval. We agree, however, that the formal petitioning process that 
we proposed is not necessary. Rather, we propose today to require you 
to justify use of Method 23 as part of the performance test plan that 
you submit to the delegated regulatory authority for review and 
approval. See proposed Sec.  63.1207(f)(1)(xxv).
    In the interim, you may request to use Method 23 in lieu of Method 
0023A under Sec.  63.7(e)(2)(i) which allows use of a test method with 
minor changes in methodology. You should submit your request and the 
supporting justification to the delegated regulatory authority.

E. Why Is EPA Not Proposing the ``Matching the Profile'' Alternative 
Approach To Establish Operating Parameter Limits?

    In response to stakeholder concerns about the stringency of 
calculating most operating parameter limits as the average of the test 
run averages of the comprehensive performance test, EPA requested 
comment in the July 3, 2001, proposed rule on an alternative approach 
to establish operating parameter limits. See 66 FR at 35138-39.
    The alternative approach, called ``matching the profile'', was 
intended to allow sources to identify limits for operating parameters 
that would allow the operating parameters to have the same average 
variability as experienced during the comprehensive performance test. 
The parameter could exceed the average achieved during the performance 
test for a period of time, provided that it was equivalently lower than 
the average for the same duration of time.
    Commenters generally note that the matching the profile approach 
has a significant disadvantage in that multiple limits would be 
established for each parameter. Accordingly, commenters recommend that 
we not include this approach in the regulation, but rather continue to 
offer it as guidance. Moreover, commenters note that sources can 
request approval of alternative monitoring approaches under Sec.  
63.1209(g)(1), and they are concerned that codification of only one 
approach, and particularly an approach with potentially limited 
utility, could lead the delegated CAA authority to conclude incorrectly 
that other approaches may not be appropriate.
    We believe that this matter is best dealt with on a site-specific 
basis, but note that by specifying one approach in the rule, we do not 
mean to preclude use of a different approach pursuant to Sec.  
63.1209(g)(1). Sources thus may request approval of the profiling 
approach, or another approach, to establish operating limits on a site-
specific basis under Sec.  63.1209(g)(1).

F. Why Is EPA Not Proposing To Allow Extrapolation of OPLs?

    In response to industry stakeholder concerns, we requested comment 
in the July 3, 2001, proposed rule on whether the rule should allow 
extrapolation of an operating parameter limit to a higher limit using a 
site-specific, empirically-derived relationship between the parameter 
and emissions of the pollutant in question.\274\ See 66 FR at 35139-40. 
We also requested comment on whether the rule should allow use of 
established engineering principles that define the relationship between 
operating parameter and emissions to extrapolate operating limits and 
emissions in lieu of a site-specific, empirically-derived relationship.
---------------------------------------------------------------------------

    \274\ Please note that the rule already allows extrapolation of 
mercury feedrates (Sec.  63.1209(l)(1)(i)) and semivolatile and low 
volatile metal feedrates (Sec.  63.1209(n)(2)(ii)).
---------------------------------------------------------------------------

    Industry stakeholders are concerned that the rule inappropriately 
penalizes sources that achieve comprehensive performance test emission 
levels well below the standard by requiring them to establish operating 
limits based on performance test operations at those low emission 
levels. They note that operating under conditions to artificially 
increase emissions during testing (e.g., by detuning emission control 
equipment) may not be feasible or desirable from a worker/public health 
and cost perspective.
    Although stakeholders acknowledge that they may request such 
extrapolation as an alternative monitoring approach under Sec.  
63.1209(g)(1), they note that explicitly defining an extrapolation 
approach in the rule may better facilitate their efforts to obtain 
approval from the delegated regulatory authority.
    Several industry stakeholders agreed with the principle of 
extrapolation as we discussed it in the July 3, 2001, notice, but 
disagreed with the requirements for, and limits on, extrapolation that 
we recommended. Several other stakeholders oppose the use of 
extrapolation generally because of concern that it is difficult to 
define completely and accurately the relationship between an operating 
parameter and emissions.
    Given the extent of the issues associated with explicitly providing 
for extrapolation of operating parameter limits, particularly on a 
categorical rather than a site-specific level, and given that you 
already have the ability to request approval of extrapolation 
procedures under Sec.  63.1209(g)(1), we are not proposing to revise 
the rule to explicitly allow extrapolation. We believe that 
extrapolation must be justified by a site-specific analysis.

G. Why Is EPA Proposing To Delete the Limit on Minimum Combustion 
Chamber Temperature for Dioxin/Furan for Cement Kilns?

    In response to stakeholder concerns that it is technically 
impracticable for cement kilns to establish a minimum combustion 
chamber temperature based on the average of the test run averages for 
each run of the comprehensive performance test, EPA requested comment 
in the July 3, 2001, proposed rule on whether the rule should continue 
to require cement kilns to establish and comply with a minimum 
combustion chamber temperature limit. See 66 FR at 35140.
    We received a total of five comments to the July 3, 2001, proposed 
rule. Three commenters opposed deleting the requirement for cement 
kilns to establish and comply with a minimum combustion chamber 
temperature.

[[Page 21344]]

Currently, cement kilns are required to establish a minimum combustion 
chamber temperature as an operating parameter limit to ensure 
compliance with the destruction and removal efficiency and dioxin/furan 
standards. See Sec. Sec.  63.1209(j)(1) and (k)(2). These commenters 
generally cited the need for monitoring combustion chamber temperature 
by noting that combustion chamber temperature is a principal factor in 
ensuring combustion efficiency and destruction of toxic organic 
compounds.
    Two commenters support deleting the minimum combustion chamber 
temperature requirements. Commenters state that a cement kiln 
inherently controls the kiln temperature to produce clinker because the 
required material temperatures must exceed approximately 2,500[deg]F 
with combustion gas temperatures higher still. These commenters note 
that a cement kiln operates well above minimum temperatures required to 
destroy the organic compounds in the hazardous waste, and, therefore, a 
minimum combustion chamber temperature limit is not necessary to 
control organic hazardous air pollutant emissions.
    Commenters also state that combustion chamber temperatures cannot 
be maintained at low enough levels for the duration of the 
comprehensive performance test to establish workable operating limits 
that would allow them to burn hazardous waste fuels economically 
without frequent waste feed cutoffs because of potential exceedances of 
the limit. Commenters indicate that combustion chamber temperature 
levels are fairly constant within a narrow range and note that there is 
a very narrow range of temperatures and feed composition in which a 
cement kiln must operate in order to produce quality clinker and a 
marketable product. Moreover, commenters state that cement kiln 
operators must take extreme actions, including potentially equipment-
damaging steps, to lower kiln temperatures to establish an economically 
viable minimum combustion chamber limit. Finally, commenters indicate 
that these problems are compounded by the requirement in the MACT rule 
to establish the hourly rolling limit based on the average of the test 
run averages (Sec. Sec.  63.1209(j)(1)(ii) and (k)(2)(ii)).
    We are not proposing to delete the requirement for cement kilns to 
establish and comply with a minimum combustion chamber temperature to 
help ensure compliance with the destruction and removal efficiency 
standard. Even though we remain reluctant to delete this requirement, 
commenters may, if they choose, provide additional comments on whether 
the rule should continue to require cement kilns to establish a minimum 
combustion chamber temperature limit as specified in Sec.  
63.1209(j)(1).
    We are, however, proposing to delete the requirement to establish a 
minimum combustion chamber temperature limit for dioxin/furan under 
Sec.  63.1209(k)(2). As mentioned above, sources are currently required 
to establish a minimum combustion chamber temperature as an operating 
parameter limit for both the destruction and removal efficiency and 
dioxin/furan standards. This proposed amendment would not affect the 
requirement for cement kilns to establish a minimum combustion chamber 
temperature under Sec.  63.1209(j)(1) during the destruction and 
removal efficiency demonstration. Currently, the destruction and 
removal efficiency demonstration need be made only once during the 
operational life of a source 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 destruction and removal 
efficiency standard. See Sec.  63.1206(b)(7). If a facility wishes to 
operate under new operating parameter limits that could be expected to 
affect the ability to meet the destruction and removal efficiency 
standard, then the source will need to conduct another destruction and 
removal efficiency test. In addition, if a source feeds hazardous waste 
at locations other than the flame zone, the destruction and removal 
efficiency demonstration must be verified during each comprehensive 
performance test and new operating parameter limits must be 
established.
    Sources that fire hazardous waste only at the flame zone (i.e., the 
kiln end where clinker product is normally discharged) are required to 
make only one destruction and removal efficiency demonstration test 
during the operational life of the kiln. During this destruction and 
removal efficiency demonstration test, the source would set a minimum 
combustion chamber temperature limit under Sec.  63.1209(j)(1) that 
would be the limit for the operational life of the kiln. However, as 
the rule is currently written, such sources would need to establish a 
minimum combustion chamber temperature limit during subsequent 
comprehensive performance tests for the dioxin/furan test under Sec.  
63.1209(k)(2). The source would be required to comply with the more 
stringent (higher) of two minimum combustion chamber temperature 
limits, which could lead to a situation where the controlling minimum 
combustion chamber temperature limit is based on the dioxin/furan test 
rather than the destruction and removal efficiency demonstration.
    We believe that this may be an inappropriate outcome given that the 
operating limit for minimum combustion chamber temperature is a more 
important parameter to ensure compliance with the destruction and 
removal efficiency standard than to ensure compliance with the dioxin/
furan standard. Our data indicate that limiting the gas temperature at 
the inlet to the particulate matter control device, an operating 
parameter limit established during each comprehensive performance test 
(Sec.  63.1209(k)(1)), is a critical dioxin/furan control parameter. We 
are, therefore, inviting comment on deleting the requirement to 
establish a minimum combustion chamber temperature limit when complying 
with the dioxin/furans standard. This proposed amendment does not 
affect the other operating parameter limits under Sec.  63.1209(k) that 
must be established for dioxin/furan such as establishing a limit on 
the gas temperature at the inlet to the particulate matter control 
device.
    For cement kilns that fire hazardous wastes at locations other than 
the flame zone, the current requirements would effectively remain the 
same. Given that a source conducts the destruction and removal 
efficiency demonstration and dioxin/furan test simultaneously and that 
a source is also required to establish a minimum combustion chamber 
temperature limit when demonstrating compliance with and establishing 
operating parameter limits for the destruction and removal efficiency 
standard, the minimum combustion chamber temperature limits is 
effectively retained.

H. Why Is EPA Requesting Additional Comment on Whether To Add a Maximum 
pH Limit for Wet Scrubbers To Control Mercury Emissions?

    We requested comment in the July 3, 2001, proposed rule as to 
whether it is appropriate to establish a limit on maximum pH to control 
mercury. See 66 FR at 35142-43. We are requesting additional comment 
today on this issue given the results of a recent study indicating that 
increasing the pH of scrubber liquid can increase mercury emissions.

[[Page 21345]]

1. What Were the Major Comments on the Discussion in the July 3, 2001, 
Proposed Rule?
    One commenter supports placing limits on the maximum pH of wet 
scrubber liquids for mercury control, but did not provide any 
additional rationale on the technical validity of the limit. Other 
commenters oppose the imposition of a maximum pH limit. One commenter 
wants to see stronger evidence that pH has an impact, and suggests a 
reproposal is needed. Another suggests that EPA conduct source testing 
to confirm that pH has an impact. Others suggest that if EPA continues 
to believe that wet scrubber operating parameter limits are important 
for mercury control, then the wet scrubber mercury operating parameter 
limits should be determined on a case-by-case basis because the 
relationship between mercury control and wet scrubber pH is not well 
established and there are numerous other factors that affect mercury 
control in wet scrubbers, especially for facilities that burn waste 
with various chemical compositions.
2. What Is the Rationale for Considering a Maximum pH Limit To Control 
Mercury?
    The use of a low pH liquid scrubber solution has been suggested to 
be beneficial for mercury control because it helps prevent the re-
release of captured mercury. Ionic mercury (Hg+\2\) is 
highly soluble in wet scrubber liquid; as opposed to Hg\o\, which has a 
very low solubility in a typical water/alkali scrubber solution. Once 
absorbed, Hg+\2\ can be reduced to Hg\o\ by compounds in the 
liquid scrubber solution such as SO2 and HSO3. 
Hg\o\ may then be revolatilized back into the stack gas. This is 
supported by numerous observations of Hg\o\ at the wet scrubber outlet 
which are higher than Hg\o\ at the scrubber inlet 
275, 276, 277. These studies suggest that the low scrubber 
liquid pH prevents captured mercury from revolatilizing from the 
scrubber liquid by: (1) limiting the capture of reducing agents; and 
(2) favoring the formation of stable mercury-chlorine compounds such as 
HgCl2 due to available Cl-. In contrast, other 
studies postulate that a high scrubber liquid pH might actually be 
beneficial for the control of mercury, particularly elemental Hg \278\. 
Basic, high pH solutions have the increased ability to absorb chlorine 
gas. Dissolved chlorine gas is suggested to enhance the scrubber's 
ability to oxidize and capture Hg\o\ (specifically, dissolved chlorine 
gas dissociates in basic solutions to produce OCl- ions 
which oxidize Hg\o\ to soluble Hg+\2\). In contrast, the 
presence of hydrogen chloride or sulfur as SO2 or 
H2SO3 in the scrubber solution reduces the liquid scrubber 
pH, reduces OCl-, and reduces the Hg\o\ oxidative potential 
of the scrubber liquid.
---------------------------------------------------------------------------

    \275\ B. Siret and S. Eagleson, ``A New Wet Scrubbing Technology 
for Control of Elemental (Metallic) and Ionic Mercury Emissions,'' 
Proceedings of 1997 Conference on Incineration and Thermal Treatment 
Technology, pp. 821-824, 1997.
    \276\ G. T. Amrhein, G. Kudlac, D. Madden, ``Full-Scale Testing 
of Mercury Control for Wet FGD Systems,'' Presented at the 27th 
International Technical Conference on Coal Utilization and Fuel 
Systems, Clearwater, Fl, March 4-7, 2002.
    \277\ C.S. Krivanek, ``Mercury Control Technologies for MWCs: 
The Unanswered Questions,'' 1993 Air and Waste Management Sponsored 
Municipal Solid Waste Combustor Specialty Conference, 1993.
    \278\ W. Linak, J. Ryan, B. Ghorishi, and J. Wendt, ``Issues 
Related to Solution Chemistry in Mercury Sampling Impingers,'' 
Journal or Air and Waste Management Association, Vol. 51, pp. 688-
698, May 2001.
---------------------------------------------------------------------------

    Although limited test data from full-scale coal fired boiler 
evaluations indicate an inconsistent impact of scrubber liquid pH on 
mercury control,\279\ a recent study \280\ confirms that ionic mercury 
(e.g., HgCl2) that is initially captured in the scrubber can 
be reduced in the liquid to elemental Hg (i.e., H\o\) and then 
revolatilized to the stack gas. The study concludes that the reduction 
of ionic mercury in the liquid is likely due to dissolved sulfur 
compounds and that decreasing the pH of the liquid will decrease the 
reduction process and subsequently decrease mercury emissions. This new 
work is additional evidence that a maximum pH limit might be 
appropriate, especially if sulfur is present in feeds.
---------------------------------------------------------------------------

    \279\ For example, McDermott Technology (McDermott Technology, 
Internet Web page at http://www.mtiresearch.com on ``Mercury 
Emission Results,'' date unknown) report no impact, while DeVito and 
Rosenhoover (M. DeVito and W. Rosenhoover, CONSOL Coal Inc., ``Flue 
Gas Hg Measurements from Coal-fired Boilers Equipped with Wet 
Scrubbers,'' date unknown) observe that mercury control efficiency 
appears to increase with increasing pH.
    \280\ J. Chang and S. Ghorishi, ``Simulation and Evaluation of 
Elemental Mercury Concentration Increase in Flue Gas Across a Wet 
Scrubber,'' Environmental Science and Technology, Vol 37, No. 24, 
2003, pp. 5763-5766.
---------------------------------------------------------------------------

    Other recent work indicates that there are numerous factors that 
influence the control of mercury in wet scrubbers. Mercury speciation 
in the flue gas is vitally important to the ability to control mercury 
in wet scrubbers. In hazardous waste combustor flue gases, mercury 
tends to be predominately in two forms: (1) elemental (Hg\o\); and (2) 
ionic (Hg+\2\, typically as HgCl2). Speciation 
depends on numerous factors including the presence of chlorine or 
sulfur, both of which are reactive with mercury. For example, increased 
levels of chlorine may increase the amount of HgCl2 and 
reduce the amount of Hg\o\. This might suggest that a minimum chlorine 
feedrate limit is needed to ensure Hg scrubber efficiency is 
maintained, which is counter to the maximum chlorine feedrate limit 
used to control emissions of total chlorine and semivolatile and low 
volatile metals. Speciation is also affected by the flue gas 
temperature cooling profile, which can impact mercury reaction 
kinetics. For example, rapid cooling may limit the equilibrium 
formation of HgCl2 (i.e., super equilibrium levels of Hg\o\ 
can survive from rapid cooling). This might suggest that a maximum flue 
gas cooling limit is needed, which is counter to that for controlling 
dioxin/furan.
    Control of mercury in wet scrubbers is also affected by the 
scrubber liquid chemical composition. As discussed above, scrubber 
liquid composition has a dramatic impact on the control of mercury. 
Specifically, the presence of reducing compounds such as SO2 
and HSO3 can lead to increased mercury emission by reducing 
soluble HgCl2 to insoluble Hg\o\ which can be desorbed while 
oxidative compounds such as chlorine gas and special oxidation 
additives such as NaClO2, acidified KMnO3, 
Na2S, and TMT (tri-mercapto-triazine) would generally help 
control mercury emissions by inhibiting reduction of HgCl2 
to Hg\o\ and/or enhancing the capture of Hg\o\.
    Finally, control of mercury in wet scrubbers is affected by the 
scrubber liquid to gas ratio.
    Given the recent study discussed above indicating that increasing 
the pH of scrubber liquid can increase mercury emissions, we request 
additional comment on whether it would be appropriate to establish a 
limit on the maximum pH of scrubber liquid to ensure compliance with 
the mercury emission standard. We also request comment on issues 
relative to establishing and complying with both a maximum limit on pH 
to control mercury emissions and a minimum limit on pH to control total 
chlorine. For example, you would establish the maximum and minimum pH 
limits under separate performance tests. You would establish the 
minimum pH limit during a performance test to demonstrate compliance 
with the total chlorine standard while you would establish the maximum 
pH limit during a performance test to demonstrate compliance with the 
mercury standard. In addition, we request comment on the anticipated 
range of pH levels between the maximum and minimum limits and whether 
the range could potentially be small enough to inhibit operations 
substantially. For example, if the pH

[[Page 21346]]

required to achieve your desired scrubber control efficiency for total 
chlorine (i.e., the minimum pH limit) is just below the pH level 
required to achieve your desired control efficiency for mercury (i.e., 
the maximum pH limit), you may have limited operating flexibility.
    Finally, we note that, in the interim until we determine whether to 
promulgate a maximum pH limit to control mercury emissions, site-
specific or other information may lead the delegated regulatory 
authority to conclude under Sec.  63.1209(g)(2) that a limit on the 
maximum pH of wet scrubber liquid may be warranted to ensure compliance 
with the mercury emission standard.

I. How Is EPA Proposing to Ensure Performance of Electrostatic 
Precipitators, Ionizing Wet Scrubbers, and Fabric Filters?

    If your combustor is equipped with a fabric filter, you would be 
required to use the bag leak detection system under Sec.  
63.1206(c)(7)(ii) to ensure performance of the fabric filter is 
maintained in lieu of operating parameter limits.\281\ In addition, we 
propose to revise the bag leak requirements under Sec.  
63.1206(c)(7)(ii) to require you to operate and maintain the fabric 
filter such that the bag leak detection system alarm does not sound 
more than 5 percent of the operating time during a 6-month period.
---------------------------------------------------------------------------

    \281\ As discussed below in the text, we propose to revise the 
current rules to delete the exemption for cement kilns from the bag 
leak detection system requirements.
---------------------------------------------------------------------------

    If your combustor is equipped with an electrostatic precipitator or 
ionizing wet scrubber, we propose to give you the option of: (1) Using 
a particulate matter continuous emissions detector for process 
monitoring to signal when you must take corrective measures to address 
maintenance or other factors causing relative or absolute mass 
particulate matter loadings to be higher than the levels achieved 
during the performance test; or (2) establishing site-specific 
operating parameter limits. If you choose to use a continuous emissions 
detector, you must not exceed the alarm set-point you establish based 
on the performance test more than 5 percent of the operating time 
during a 6-month period. If you choose to establish site-specific 
operating parameter limits, you must link each limit to the automatic 
waste feed cutoff system.
1. What Is the Background of this Issue?
    The current regulations require you to establish site-specific 
operating parameter limits to ensure performance of electrostatic 
precipitators, ionizing wet scrubbers, and fabric filters. See Sec.  
63.1209(m)(1)(iv).\282\ Regulatory officials review and approve those 
operating parameter limits and may require additional or alternative 
limits under Sec.  63.1209(g)(2).
---------------------------------------------------------------------------

    \282\ Please note that Sec.  63.1209(m)(1)(iv) inadvertently 
indicates that the requirement to establish site-specific operating 
limits applies to control devices other than ionizing wet scrubbers, 
baghouses, and electrostatic precipitators. We should have revised 
that paragraph to require site-specific operating parameter limits 
for those control devices when we revised paragraph (m)(1) to delete 
the operating parameter limits for those devices. The delegated 
regulatory authority can use Sec.  63.1209(g)(2) to require you to 
establish site-specific operating parameter limits for those control 
devices prior to the effective date of the final rule based on 
today's proposed rule.
---------------------------------------------------------------------------

    In the July 3, 2001 proposed rule, we requested comment on how to 
establish prescriptive requirements to ensure performance of these 
control devices. See 66 FR at 35143-45. We requested comment on four 
approaches to ensure performance of electrostatic precipitators: (1) 
Requiring an increasing kVA pattern across the electrostatic 
precipitator; (2) limiting kVA on only the back \1/3\ of fields; (3) 
use of a CMS that measures relative particulate matter loadings; and 
(4) use of predictive emission monitoring systems. These approaches 
would also be applicable to ionizing wet scrubbers. We also requested 
comment on whether and how cell pressure drop should be used to ensure 
performance of fabric filters.
    We received comments in favor of and opposing most of these 
approaches.\283\ Some stakeholders also recommend other approaches. One 
commenter favors use of specific power as an operating parameter for 
electrostatic precipitator performance. Specific power is the secondary 
power/gas flow rate. Another commenter suggests continuing with 
establishing site-specific operating parameter limits.
---------------------------------------------------------------------------

    \283\ USEPA, ``Response to Comments on July 2001 Proposed 
Rule,'' March 2004.
---------------------------------------------------------------------------

 2. What Is the Rationale for Proposing to Revise the Compliance 
Requirements for Fabric Filters?
     After reviewing comments and further investigation, we conclude 
that controls in addition to a bag leak detection system are not needed 
to ensure performance of fabric filters. Use of pressure drop to ensure 
performance is problematic for reasons we discussed in the July 3, 2001 
proposed rule. Moreover, the bag leak detection system provides a 
direct measure of small (and greater) increases in particulate matter 
loading that enable you to take immediate corrective measures.
    We conclude, however, that the bag leak detection system 
requirements under Sec.  63.1206(c)(7)(ii) are not prescriptive enough 
to ensure proper operation and maintenance of the fabric filter. 
Current provisions require you to take immediate corrective measures 
when the bag leak detection system alarm sounds, indicating that 
particulate loadings exceed the set-point. There is no limit on the 
duration of time, however, that the bag house may be operating under 
these conditions. To ensure that you take both corrective and proactive 
measures to minimize the frequency and duration of bag leak detection 
system alarms, you must operate and maintain the fabric filter to 
ensure that the bag leak detection system alarm does not sound more 
than 5 percent of the operating time during a 6-month period.\284\ We 
note that the Agency also proposed this requirement for boilers and 
process heaters that do not burn hazardous waste. See 68 FR at 1708 
(January 13, 2003). If you exceed the alarm set-point more than 5 
percent of the time during a 6-month period, you would be required to 
notify the delegated regulatory authority within 5 days. In the 
notification, you must describe the causes of the excessive exceedances 
and the revisions to the design, operation, or maintenance of the 
combustor or baghouse you are taking to minimize exceedances. This 
notification would alert the regulatory authority of the excessive 
exceedances so that they may review and confirm the corrective measures 
you are undertaking. See proposed Sec.  63.1206(c)(7)(ii)(C).
---------------------------------------------------------------------------

    \284\ Periods of time when the combustor is operating but the 
bag leak detection system is malfunctioning must be considered 
exceedances of the set-point.
---------------------------------------------------------------------------

    We also conclude that the current exemption from the bag leak 
detection system requirements for cement kilns should be eliminated. We 
did not require bag leak detection systems for cement kilns in the 
September 1999 Final Rule because cement kilns are subject to an 
opacity standard and must monitor opacity with a continuous monitor. As 
a practical matter, however, the opacity levels achieved during the 
comprehensive performance test will be lower, often substantially 
lower, than the opacity standard. Thus, absent effective operating 
parameter limits on the fabric filter based on performance test 
operations, we cannot ensure that performance is maintained at the 
level achieved during the performance test (and that you remain in 
compliance with the particulate matter and other

[[Page 21347]]

standards \285\). Consequently, we propose to require that cement kilns 
comply with the bag leak detection requirements (as proposed to be 
revised) under Sec.  63.1206(c)(7)(ii).\286\ We note that, although 
triboelectric detectors are generally used as bag leak detectors given 
their ability to detect very low loadings of particulate matter, cement 
kilns may use the transmissometers they currently use for opacity 
monitoring provided that the transmissometer is sensitive enough to 
detect subtle increases in particulate matter loading over normal (not 
performance test) loadings.
---------------------------------------------------------------------------

    \285\ Because controlling particulate matter also controls 
semivolatile and low volatile metals (and dioxin/furan if you use 
activated carbon injection), exceeding the particulate matter 
loadings achieved during the performance test is also evidence of 
failure to ensure compliance with the emission standards for those 
pollutants.
    \286\ Because the proposed bag leak detection requirements are 
more stringent than the opacity standard, exempting cement kilns 
from the New Source Performance Standards for particulate matter and 
opacity under Sec.  60.60 continues to be appropriate. See 
Sec. Sec.  63.1204(h) and 63.1220(h).
---------------------------------------------------------------------------

    Finally, we request comment on whether it is practicable to 
establish the alarm set-point for the back leak detection system based 
on the detector response achieved during the performance test rather 
than as recommended in the Agency's guidance document.\287\ The 
guidance document recommends that you establish the alarm set-point at 
a level that is twice the detector response achieved during bag 
cleaning. Although establishing the set-point at this level would avoid 
frequent exceedances due to normal bag cleaning, we are concerned that 
it may not be low enough to detect gradual degradation in fabric filter 
performance that, for example, can be caused by pinholes in the bags. 
Moreover, establishing the set-point at a detector response that is 
twice the response achieved during bag cleaning may not be low enough 
to require you to take corrective measures if particulate matter 
loadings increase above the levels achieved during the performance 
test, and thus at loadings that may indicate an exceedance of the 
particulate matter emission standard. To avoid alarms caused by bag 
cleaning cycles, the alarm set-point would be established as the 
average detector response of the test run averages during the 
particulate matter performance test, and would be established as a 6-
hour rolling average updated each hour with a one-hour block average. 
This is the time that could be required to conduct three runs of a 
particulate matter performance test. The one-hour block average would 
be the average of the detector responses over each 15-minute block.
---------------------------------------------------------------------------

    \287\ USEPA, ``Fabric Filter Bag Leak Detection Guidance,'' 
September 1997.
---------------------------------------------------------------------------

3. What Is the Rationale for Proposing to Revise the Compliance 
Requirements for Electrostatic Precipitators and Ionizing Wet 
Scrubbers?
    We propose a two-tiered approach to ensure performance of 
electrostatic precipitators and ionizing wet scrubbers: (1) Use of a 
particulate matter continuous emissions detector for process monitoring 
to signal when you must take corrective measures to address maintenance 
or other factors causing relative or absolute mass particulate matter 
loadings to be higher than the levels achieved during the performance 
test; or (2) use of site-specific operating parameter limits. You could 
choose to comply with either tier.
    a. How Would Tier I Work? Under Tier I, you would use a particulate 
matter continuous emissions detector for process monitoring to signal 
when you must take corrective measures to address maintenance or other 
factors causing relative or absolute mass particulate matter loadings 
to be higher than the levels achieved during the performance test. You 
would establish an alarm set-point as the average detector response 
achieved during the particulate matter emissions performance test. The 
limit would be applied as a 6-hour rolling average updated each hour 
with a one-hour block average to correspond to the time it could take 
to conduct three runs of a performance test. The one-hour block average 
would be the average of the detector responses over each 15-minute 
block.
    If you exceed the alarm set-point, you must immediately take the 
corrective measures you specify in your operation and maintenance plan 
to bring the response below the set-point. To ensure that you take both 
corrective and proactive measures to minimize the frequency and 
duration of exceedances, you would be required to operate and maintain 
the electrostatic precipitator and ionizing wet scrubber to ensure that 
the alarm set-point is not exceeded more than 5 percent of the 
operating time during a 6-month period.\288\ This is consistent with 
the proposed requirement to limit the period of time that a fabric 
filter may be operating under conditions of poor performance. If you 
exceed the alarm set-point more than 5 percent of the time during a 6-
month period, you would be required to notify the delegated regulatory. 
This notification would alert the regulatory authority of the excessive 
exceedances so that they may take corrective measures, such as 
requiring you to revise the operation and maintenance plan.
---------------------------------------------------------------------------

    \288\ Periods of time when the combustor is operating but the 
bag leak detection system is malfunctioning must be considered 
exceedances of the set-point.
---------------------------------------------------------------------------

    You may use any detector as a particulate matter continuous monitor 
provided that the detector response correlates with relative or 
absolute particulate matter mass emissions and that it can detect small 
changes in particulate matter loadings.\289\ You would include in the 
performance test plan a description of the particulate matter detector 
you select and information documenting that the detector response 
correlates with relative or absolute particulate matter loadings and 
that the detector can detect small changes in particulate matter 
loadings above the levels anticipated during the comprehensive 
performance test. For example, if you anticipate to achieve a 
particulate matter emission level of 0.010 gr/dscf during the 
comprehensive performance test, your detector should be able to 
distinguish between particulate matter loadings of 0.010 gr/dscf and 
0.011 gr/dscf.
---------------------------------------------------------------------------

    \289\ Please note that, for the purpose of process monitoring 
proposed here, you need not correlate the particulate matter 
detector to particulate matter emission concentrations.
---------------------------------------------------------------------------

    b. How Would Tier II Work? Under Tier II, you would comply with 
site-specific operating parameter limits you establish under Sec.  
63.1209(m)(1)(iv). As currently required, the operating limits would be 
linked to the automatic waste feed cutoff system. Exceedance of an 
operating limit would be a violation and is evidence of failure to 
ensure compliance with the particulate matter, semivolatile metal, and 
low volatile metal emission standards.

IV. Other Proposed Compliance Revisions

A. What Is the Proposed Clarification to the Public Notice Requirement 
for Approved Test Plans?

    We are proposing in today's notice to add clarifying language to 
the section 1207(e)(2) public notification requirement for approved 
performance test and CMS performance evaluation test plans. The Agency 
believes that adequate public involvement is an essential element to 
the continuing and successful management of hazardous waste. Providing 
opportunities for timely and adequate public notice is necessary to 
fully inform nearby communities of a source's plans to initiate 
important waste management

[[Page 21348]]

activities. In 1995, we expanded the RCRA public participation 
requirements for hazardous waste combustion sources to require that the 
State Director issue a public notice prior to a source conducting a 
RCRA trial burn emission test. See 60 FR 63417, 40 CFR 270.62(b)(6) and 
40 CFR 270.66(d)(3). The purpose of this notification requirement was 
to inform the public of an upcoming trial burn should an individual be 
interested in reviewing the results of the test. When we promulgated 
the Phase I hazardous waste combustion NESHAP in 1999, we included a 
similar requirement in subpart EEE for the same general purpose. 
Section 1207(e)(2) of subpart EEE requires that sources issue a public 
notice announcing the approval of site-specific performance test plans 
and CMS performance evaluation test plans and provide the location 
where the plans will be made available to the public for review. We 
neglected, however, to include direction regarding how and when sources 
should notify the public, what the notification should contain, or 
where and for how long the test plans should be made available. As a 
result, we are proposing to add clarifying language to the section 
1207(e)(2) public notification requirement. We are using the RCRA trial 
burn notification requirements as a foundation for the proposed 
clarifications.
1. How Should Sources Notify the Public?
    The source must make a reasonable effort to provide adequate 
notification of the approval of their site-specific performance test 
and CMS performance evaluation test plans. Because this notification is 
intended for informational purposes only, we are proposing that sources 
use their facility/public mailing list. We expect that by the time a 
source receives approval of its subpart EEE test plans, a facility/
public mailing list already would have been developed in response to 
the source's RCRA and CAA permitting activities. As such, we are 
proposing that sources use the facility/public mailing list developed 
under 40 CFR 70.7(h)(1), 71.11(d)(3)(i)(E) and 124.10(c)(1)(ix), for 
purposes of this notification. Sources may voluntarily choose to use 
other mechanisms in addition to a distribution to the facility/public 
mailing list, if previous experience has shown that such additional 
mechanisms are necessary to reach all interested segments of the 
community. For example, sources may consider using press releases, 
advertisements, visible signs, and outreach to local community, 
professional, and interest groups in addition to the required 
distribution to the facility/public mailing list.
2. When Should Sources Notify the Public of Approved Test Plans?
    The existing regulations require that sources issue a public notice 
after the Administrator has approved the site-specific performance test 
and CMS performance evaluation test plans. It is important to remember 
that the purpose of this notification is similar to that required under 
RCRA for trial burn tests. See 60 FR 63417, 40 CFR 270.62(b)(6) and 40 
CFR 270.66(d)(3). The notification is intended to provide information 
to the public regarding the upcoming performance test. It is not 
intended to solicit comment on the performance test plan. We considered 
proposing that the notification occur within 30 days of the source's 
receipt of test plan approval. However, we chose not to proceed with 
this option because we were concerned that the notification would not 
be as meaningful to the public if too much time elapses between the 
test plan approval notification and the actual initiation of the 
performance test. In order to provide the public with adequate notice 
of the upcoming test and a reasonable period of time to review the 
approved plans prior to the test, we are proposing that the source 
issue its notice after test plan approval, but no later than 60 days 
prior to conducting the test. We believe that this also will allow the 
source sufficient time to prepare its public notice and corresponds to 
the 40 CFR 63.1207(e)(1)(i)(B) requirement for a source to notify the 
Administrator of its intention to initiate the test.
3. What Should the Notification Include?
    Similar to the public involvement requirements for RCRA trial burn 
tests, we are proposing that the notification contain the following 
information:
    (1) The name and telephone number of the source's contact person;
    (2) The name and telephone number of the regulatory agency's 
contact person;
    (3) The location where the approved performance test and CMS 
performance evaluation test plans and any necessary supporting 
documentation can be reviewed and copied;
    (4) The time period for which the test plans will be available for 
public review, and;
    (5) An expected time period for commencement and completion of the 
performance test and CMS performance evaluation test.
4. Where Should the Plans Be Made Available and for How Long?
    The site-specific performance test and CMS performance evaluation 
test plans must be made available at an unrestricted location which is 
accessible to the public during reasonable hours and provides a means 
for the public to obtain copies of the plans if needed. To provide for 
adequate time for the public to review the test plans, we are proposing 
that the plans be made available for a total of 60 days, beginning on 
the date that the source issues its public notice.

B. What Is the Proposed Clarification to the Public Notice Requirement 
for the Petition To Waive a Performance Test?

    Sources that petition the Administrator for an extension of time to 
conduct a performance test (in other words, obtain a performance test 
waiver), are required under section 1207(e)(3)(iv) to notify the public 
of their petition. Although the regulatory language does provide some 
direction regarding how the source may notify the public (e.g., using a 
public mailing list), it does not provide any direction regarding when 
this notice must be issued or what it must contain. As a result, we are 
proposing in today's notice to add clarifying language to the Section 
1207(e)(3)(iv) public notice requirement.
1. When Should Sources Notify the Public of a Petition To Waive a 
Performance Test?
    We are proposing that a source notify the public of a petition to 
waive a performance test at the same time that the source submits its 
petition to the Administrator. Although not explicitly stated in 
section 1207(e)(3)(iv), this was our original intent. In the July 3, 
2001, preamble to the subpart EEE proposed technical amendments, we 
provided a time line of the waiver petitioning process for an initial 
Comprehensive Performance Test.\290\ In that time line, we indicated 
that the submittal of the petition and the public notification should 
occur at the same time.
---------------------------------------------------------------------------

    \290\ It should be noted that the petition for waiver of a 
performance test applies to both the initial test and all subsequent 
tests. See 40 CFR 1207(e)(3).
---------------------------------------------------------------------------

2. What Should the Notification Include?
    The notification of a petition to waive a performance test is an 
informational notification. As such, we are proposing that it include 
the same level of information as that provided by a source for the 
notification of an approved test plan:

[[Page 21349]]

    (1) The name and telephone number of the source's contact person;
    (2) The name and telephone number of the regulatory agency's 
contact person;
    (3) The date the source submitted its site-specific performance 
test plan and CMS performance evaluation test plans; and
    (4) The length of time requested for the waiver.

Part Four: Impacts of the Proposed Rule

I. What Are the Air Impacts?

    Table 1 of this preamble shows the emissions reductions achieved by 
the proposed rule for all existing hazardous waste combustor sources. 
For Phase I sources--incinerators, cement kilns, and lightweight 
aggregate kilns--the emission reductions represent the difference in 
emissions between sources controlled to the proposed standards and 
estimated emissions when complying with the interim MACT standards 
promulgated on February 13, 2002. For Phase II sources--industrial/
commercial/institutional boilers and process heaters and hydrochloric 
acid production facilities--the reductions represent the difference in 
emissions between the proposed standards and the current baseline of 
control provided by 40 CFR part 266, subpart H.
    Nationwide baseline HAP emissions from hazardous waste combustors 
are estimated to be approximately 13,000 tons per year at the current 
level of control. Today's proposed standards would reduce emissions of 
hazardous air pollutants and particulate matter by approximately 3,300 
tons per year.
    Nationwide emissions of dioxin/furans from all hazardous waste 
combustors will be reduced by 4.7 grams TEQ per year. Emissions of HAP 
metals from all hazardous waste combustors will be reduced by 23 tons 
per year, including one ton per year of mercury. We estimate that 
particulate matter itself, a surrogate for HAP metals will be reduced 
by over 1,700 tons per year. Finally, emissions of hydrogen chloride 
and chlorine gas from all hazardous waste combustors will reduced by 
nearly 1,500 tons and over 100 tons per year, respectfully.\291\ A 
discussion of the emission estimates methodology and results is 
presented in ``Draft Technical Support Document for HWC MACT 
Replacement Standards, Volume V: Emission Estimates and Engineering 
Costs'' (Chapter 3) in the docket for today's proposal.
---------------------------------------------------------------------------

    \291\ We are, however, proposing to establish alternative risk-
based standards, pursuant to CAA section 112(d)(4), which could be 
elected by the source in lieu of the MACT emission standards for 
total chlorine. The emission limits would be based on national 
exposure standards that ensure protection of public health with an 
ample margin of safety. See Part Two, Section XIII for additional 
details.If we were to adopt alternative risk-based standards, then 
the national annual emissions reductions for total chlorine are 
overstated.

   Table 1.--Nationwide Annual Emissions Reductions of HAPs and Other
                               Pollutants
------------------------------------------------------------------------
                                                           Estimated
                                                            emission
                      Pollutant                         reductions (tons
                                                         per year) \1\
------------------------------------------------------------------------
Dioxin/furans........................................               0.3
Mercury..............................................               0.93
Cadmium..............................................               0.50
Lead.................................................               3.30
Arsenic..............................................               1.27
Beryllium............................................               0.31
Chromium.............................................               8.97
Antimony.............................................               1.18
Cobalt...............................................               0.42
Nickel...............................................               1.57
Selenium.............................................               0.28
Manganese............................................               4.50
Hydrogen Chloride....................................            1470
Chlorine Gas.........................................             107
Particulate Matter...................................           1727
------------------------------------------------------------------------
\1\ Dioxin/furan emissions reductions and reductions expressed as grams
  TEQ.

II. What Are the Water and Solid Waste Impacts?

    We estimate that water usage would increase by 4.8 billion gallons 
per year if the proposed MACT standards were adopted. In addition to 
the increased water usage, an additional 4.6 billion gallons per year 
of wastewater would be produced. We estimate the additional solid waste 
that would need to be treated as a result of the proposed standards to 
be 10,400 tons per year. The costs associated with these hazardous 
waste treatment/disposal and water requirements are accounted for in 
the national annualized compliance cost estimates. A discussion of the 
methodology used to estimate impacts is presented in ``Draft Technical 
Support Document for HWC MACT Replacement Standards, Volume V: Emission 
Estimates and Engineering Costs' (Chapters 4 and 5) that is available 
in the docket.

III. What Are the Energy Impacts?

    We estimate an increase of approximately 133 million kilowatt hours 
(kWh) in national annual energy usage as a result of the proposed 
standards. The increase results from the electricity required to 
operate air pollution control devices installed to meet the proposed 
standards, such as baghouses and wet scrubbers.

IV. What Are the Control Costs?

    Control costs, as presented in this section, refer only to 
engineering, operation, and maintenance costs associated with unit/
system upgrades necessary to meet the proposed replacement standards. 
These costs do not incorporate any market-based adjustments. All costs 
presented in this section are annualized estimates in 2002 dollars.
    We estimate there are a total of 276 sources \292\ that may be 
subject to requirements of the proposed rule. Liquid and solid fuel 
boilers represent approximately 43 percent of this total, followed by 
on-site incinerators at 33 percent, and cement and lightweight 
aggregate kilns at 12 percent. Commercial incinerators and hydrochloric 
acid production furnaces make up the remaining 12 percent of the total.
---------------------------------------------------------------------------

    \292\ For purposes of this discussion, a source is defined as 
the air pollution control system associated with the hazardous waste 
combustion unit(s). A source may contain one or more combustion 
units, and a facility may operate one or more sources.
---------------------------------------------------------------------------

    Total national engineering costs for the proposed standards are 
estimated to range from $57.7 million to $77.9 million per year. The 
low end of this range reflects total upgrade costs excluding controls 
to meet the total chlorine standard.\293\ All Phase II sources combined 
represent about 66 percent or 80 percent of this total, depending upon 
section 112(d)(4) scenario. The average cost per source is expected to 
be highest for lightweight aggregate kilns and solid fuel boilers, 
ranging from $329,000 to $400,000 and $217,000 to $283,000, 
respectively. Average liquid fuel boiler costs range from $378,000 to 
$419,000 per system. Hydrochloric acid production furnaces were found 
to have average system costs of about $200,000 under both section 
112(d)(4) scenarios. On-site incinerators and commercial incinerators 
were found to generally have the lowest average cost ranges. Average 
annualized engineering costs for on-site incinerators are estimated to 
range from $16,300 to $139,000 per source, while average annual per 
source engineering costs for commercial incinerators are estimated to 
range from $67,000 to $247,000. For all Phase I sources (140 sources; 
commercial incinerators, on-site incinerators, cement kilns, and

[[Page 21350]]

lightweight aggregate kilns), average annualized engineering costs are 
estimated to range from $76,000 to $184,000 per source. The combined 
Phase II sources (136 sources; solid and liquid fuel-fired boilers and 
hydrochloric acid production furnaces) had average annualized 
engineering costs ranging from $341,000 to $380,000 per source. Across 
all sectors covered by today's proposal (Phase I and Phase II sources), 
average annualized costs were found to range from $209,000 to $282,000 
per source.
---------------------------------------------------------------------------

    \293\ We are proposing using section 112(d)(4) of the Clean Air 
Act to establish risk-based standards for total chlorine for 
hazardous waste combustors (except for hydrochloric acid production 
furnaces). The low-end of this cost range assumes all facilities 
emit total chlorine levels below risk-based levels of concern. Under 
this scenario, no total chlorine controls are assumed to necessary.
---------------------------------------------------------------------------

    Engineering compliance (control) costs have also been assessed on a 
per ton of waste burned basis. Captive energy recovery sources 
(includes solid and liquid fuel-fired boilers, and hydrochloric acid 
production furnaces), burning a total of 1,001,500 tons of hazardous 
waste per year, are projected to experience the highest average 
incremental costs, ranging from $46 to $52 per ton. Commercial energy 
recovery sources (cement kilns and LWAKs), burning approximately 
1,093,800 tons per year, may see incremental control costs ranging from 
$7.50 to $8.50 per ton. Captive (on-site) and commercial incinerators 
burn an estimated 1,010,600 tons and 452,200 tons per year, 
respectively. These sources are estimated to experience average 
incremental engineering costs ranging from $1.50 to $12.70 per ton for 
captive and $2.20 to $8.20 per ton for commercial sources.
    The aggregate control costs presented in this section do not 
reflect the anticipated real world cost burden on the economy. Any 
market disruption, such as the implementation of hazardous waste MACT 
or risk-based standards will cause a short-tem disequilibrium in the 
hazardous waste burning market. Following the implementation of the 
replacement standards, market adjustments will occur in a natural 
economic process designed to reach a new market equilibrium. Actual 
cost impacts to society are more accurately measured by taking into 
account market adjustments. These costs are commonly termed Social 
Costs, and are generally less than total engineering costs due to cost 
efficiencies implemented during the market adjustment process. Social 
Costs theoretically represent the total real world costs of all goods 
and services society must give up in order to gain the added protection 
to human health and the environment. Social Costs are presented in Part 
VIII of this Section.

V. Can We Achieve the Goals of the Proposed Rule in a Less Costly 
Manner?

    Section 1(b)(3) of Executive Order 12866 instructs Executive Branch 
Agencies to consider and assess available alternatives to direct 
regulation prior to making a determination for regulation. This 
regulatory determination assessment should be considered, ``to the 
extent permitted by law, and where applicable.'' The ultimate purpose 
of the regulatory determination assessment is to ensure that the most 
efficient tool, regulation, or other type of action is applied in 
meeting the targeted objective(s). Requirements for MACT standards 
under the Clean Air Act, as mandated by Congress, have compelled us to 
select today's regulatory approach. Furthermore, we are under legal 
obligation to meet the targeted objectives of today's proposal through 
a regulatory action. As a result, alternatives to direct regulatory 
action were not evaluated.
    In addition to the statutory and legal mandates necessitating 
today's proposed rulemaking, we believe that federal regulation is the 
most efficient approach for helping to correct 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.
    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 a regulatory action was not 
implemented.
    We believe that the market has generally failed to correct the air 
pollution problems resulting from the combustion of hazardous wastes 
for several reasons. First, there exists no natural market incentive 
for hazardous waste combustion facilities to incur additional costs 
implementing control measures. This occurs 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 environmental externality occurs because 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 source) through legal or other means.\294\ 
Finally, emissions from hazardous waste combustion facilities directly 
affect a ``public good,'' the air. Improved air quality benefits human 
health and the environment. The absence of government intervention, 
therefore, will perpetuate a market that fails to fully internalize key 
negative externalities, resulting in a sub-optimal quantity and quality 
of public goods, such as air.
---------------------------------------------------------------------------

    \294\ Some economists consider this a failure of full and proper 
enforcement of property rights.
---------------------------------------------------------------------------

    We have assessed several regulatory options designed to mitigate 
the unacceptable levels of risk to human health and the environment 
resulting from the combustion of hazardous waste in the targeted units. 
We believe, based on available data, that our preferred regulatory 
approach,\295\ as presented in today's proposed rule, is the most cost-
efficient method for reducing the level of several hazardous air 
pollutants. These include: dioxin and furan, mercury, semivolatile and 
low volatile metals, and total chlorine emissions (i.e., hydrogen 
chloride and chlorine). Carbon monoxide, hydrocarbons, and particulate 
matter will also be reduced.
---------------------------------------------------------------------------

    \295\ Including our proposal to apply section 112(d)(4) to 
establish risk-based standards for total chlorine for all sources, 
except hydrochloric acid production furnaces.
---------------------------------------------------------------------------

    We evaluated seven alternative methodologies in the development of 
today's proposed approach. These were: system removal efficiency plus 
feed control, straight emission-based, modified emission-based, 
exclusive technology approach, simultaneous achievability, using the 
CAA section 112(d)(4) to establish risk-based standards for total 
chlorine, and beyond-the-floor. Numerous different combinations of 
these methodologies were assessed. Selection of the Agency preferred 
approach was based, in part on methodological clarity, implementation 
simplicity, cost and economic impacts, stakeholder input, and necessary 
protectiveness to human health and the environment.

[[Page 21351]]

VI. What Are the Economic Impacts?

    Various market adjustments (i.e., economic impacts) are expected in 
response to the changes in hazardous waste combustion costs anticipated 
as a result of the replacement standards, as proposed. Economic impacts 
may be measured through several factors. This section presents 
estimated economic impacts relative to market exits, waste 
reallocations, and employment impacts. Economic impacts presented in 
this section are distinct from social costs, which correspond only to 
the estimated monetary value of market disturbances.

A. Market Exit Estimates

    The hazardous waste combustion industry operates in a dynamic 
market, with systems entering and exiting the market on a routine 
basis. Our analysis defines ``market exit'' as ceasing to burn 
hazardous waste. We have projected post-rule hazardous waste combustion 
system market exits based on economic feasibility only. Market exit 
estimates are derived from a breakeven analysis designed to determine 
system 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.)
    Under the Agency's proposed approach, we estimate there may be 
anywhere from 51 to 58 systems (sources) that stop burning hazardous 
waste. This represents anywhere from 18 percent to 21 percent of the 
total number of systems affected by the rule. The range is based on the 
inclusion or exclusion of total chlorine controls.\296\ At the high-end 
of this range, onsite incinerators represent about 55 percent of the 
total number of market exits. Liquid and solid fuel boilers (includes 
process heaters) account for 41 percent, and commercial incinerators 
account for the remaining. No cement kilns, lightweight aggregate 
kilns, or hydrochloric acid production furnaces are projected to exit 
the market as a result of the rule. Market exits are estimated to 
change only slightly under the alternative regulatory options.
---------------------------------------------------------------------------

    \296\ Even though we are proposing to allow sources (except 
hydrochloric acid production furnaces) to invoke section 112(d)(4) 
in lieu of MACT chlorine control requirements, we have not attempted 
to estimate the following: (1) The total number of sources that may 
elect to implement this provision, and, (2) what level of control 
may be necessary following a section 112(d)(4) risk-based 
determination, since this would vary on a site-by-site basis.
---------------------------------------------------------------------------

B. Quantity of Waste Reallocated

    Some combustion systems (sources) may no longer be able to cover 
their hazardous waste burning costs as a result of rule requirements, 
as proposed. These sources are expected to divert or reroute their 
wastes to alternative burners.\297\ For multiple system facilities, 
this diversion may include on-site (non-commercial) waste consolidation 
among fewer systems at the same facility. A certain portion of this 
waste may also be reallocated to waste management alternatives (e.g., 
solvent reclamation). Combustion, however, is likely to remain the 
lowest cost option. Thus, we expect that the vast majority of 
reallocated waste will continue to be managed at combustion facilities.
---------------------------------------------------------------------------

    \297\ This analysis includes the cost of waste transport to 
alternative combustion sources, burning fees, and purchase of 
alternative fuels (if appropriate).
---------------------------------------------------------------------------

    Our economic model indicates that, in response to today's rule, 
approximately 87,500 to 120,900 tons of hazardous waste may be 
reallocated, representing up to 3.4 percent of the total 1999 estimated 
quantity of hazardous waste burned at all sources. This estimate 
includes on-site consolidations and off-site diversions. Off-site 
diversions alone represent no more than 1.5 percent of the total waste 
burned. About 56 percent to 65 percent of the total reallocated waste 
quantity is expected to be consolidated among fewer systems at the same 
non-commercial facility. Commercial incinerators and commercial energy 
recovery (cement kilns and lightweight aggregate kilns) facilities are 
projected to receive all hazardous waste that is rerouted off-site. 
Onsite incinerators and boilers are the primary source of all off-site 
diverted waste. Based on the high estimate for total waste reallocated 
(120,900 tons), commercial incinerators and cement kilns are projected 
to receive 37 percent and 7 percent, respectively. The remainder, as 
mentioned above, is projected to be consolidated on-site. Currently, 
there is more than adequate capacity to accommodate all off-site waste 
diversions.

C. Employment Impacts

    Today's rule is likely to cause employment shifts across all of the 
hazardous waste combustion sectors. These shifts may 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 or experience forced relocations. 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 selected 
combustion facilities to accommodate reallocated waste and/or various 
compliance activities.
1. Employment Impacts--Dislocations (losses)
    Primary employment dislocations (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 proposed replacement standards are estimated to range from 308 
to 387 full-time-equivalent (FTE) jobs. Depending upon the scenario, 
on-site incinerators and boilers are responsible for anywhere from 
about 85 to 100 percent all potential job dislocations. Their 
significant share of the losses is a function of both the large number 
of systems affected, and the number of expected exits within these 
sectors.
2. Employment Impacts--Gains
    In addition to employment dislocations, today's rule is also 
expected to result in job gains. These gains are projected to occur to 
both the air pollution control industry and to combustion firms as they 
hire personnel to accommodate reallocated waste and/or comply with the 
various requirements of the rule. Hazardous waste combustion sources 
are projected to need additional operation and maintenance personnel 
for the new pollution control equipment and other compliance 
activities, such as new reporting and record keeping requirements.
    The total annual employment gains associated with the proposed 
standards are estimated to range from 407 to 525 FTEs. Job gains to the 
air pollution

[[Page 21352]]

control industry \298\ represent about 31 percent of this total. Among 
all combustors, boilers are projected to experience the greatest number 
of job gains, followed by cement and lightweight aggregate kilns. Job 
gains in these sectors alone represent about 55 percent to 61 percent 
of total projected gains, depending upon regulatory scenario.
---------------------------------------------------------------------------

    \298\ Manufacturers and distributers of air pollution control 
devices are expected to increase sales as a result of this action.
---------------------------------------------------------------------------

    While it may appear that this analysis suggests overall net job 
creation, 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 potential job 
displacement across sectors. This may occur if investment funds are 
diverted from other areas of the larger economy.

VII. What Are the Benefits of Reductions in Particulate Matter 
Emissions?

    For the 1999 rule, we estimated the avoided incidence of mortality 
and morbidity associated with reductions in particulate matter (PM) 
emissions.\299\ Estimates of cases of mortality and morbidity avoided 
were made for children and the elderly, as well as the general 
population, using concentration-response functions derived from human 
epidemiological studies. Morbidity effects included respiratory and 
cardiovascular illnesses requiring hospitalization, as well as other 
illnesses not requiring hospitalization, such as acute and chronic 
bronchitis and acute upper and lower respiratory symptoms. Decreases in 
particulate matter-related minor restricted activity days (MRADs) and 
work loss days (WLDs) were also estimated. Rates of avoided incidence, 
work days lost, and days of restricted activity were estimated for each 
of 16 sectors surrounding a facility using the concentration-response 
functions and sector-specific estimates of the corresponding population 
and model-derived ambient air concentration, either annual mean 
PM10 or PM2.5 concentrations or distributions of 
daily PM10 or PM2.5 concentrations, depending on 
the concentration-response function. The sectors were defined by 4 
concentric rings out to a distance of 20 kilometers (about 12 miles), 
each of which was divided into 4 quadrants. The sector-specific rates 
were weighted by facility-specific sampling weights and then summed to 
give the total incidence rates for a given source category.\300\
---------------------------------------------------------------------------

    \299\ See ``Human Health and Ecological Risk Assessment Support 
to the Development of Technical Standards for Emissions from 
Combustion Units Burning Hazardous Wastes: Background Document,'' 
July 1999.
    \300\ It should be noted that the avoided incidence estimates 
were based entirely on the incremental decrease in ambient air 
concentrations associated with emission controls on the hazardous 
waste sources subject to the 1999 rule. Background levels of 
particulate matter were assumed to be sufficiently high to exceed 
any possible threshold of effect but ambient background levels of 
particulate matter were not otherwise considered in the analysis.
---------------------------------------------------------------------------

    Since performing the risk assessment for the 1999 Assessment, the 
Agency has updated its benefits methodology to reflect recent advances 
in air quality modeling and human health benefits modeling. To estimate 
PM exposure for the 1999 risk assessment, the Agency used the 
Industrial Source Complex Model-Short Term Version 3 (ISCST3). More 
recent EPA benefits analyses have used more advanced air-quality 
models. For example, the Agency's assessment of the industrial boilers 
and process heaters NESHAP used the Climatological Regional Dispersion 
Model (CRDM), which uses a national source-receptor matrix to estimate 
exposure associated with PM emissions.\301\ Similarly, the Agency's 
analysis of the proposed Inter-state Air Quality Rule used the Regional 
Modeling System for Aerosols and Deposition (REMSAD), which also 
accounts for the long-range transport of particles.\302\ In contrast, 
ISCST3 modeled exposure within a 20-kilometer radius of each emissions 
source for the 1999 risk assessment.\303\ To the extent that PM is 
transported further than 20 km from each emissions source, the 1999 
risk assessment may underestimate PM exposure. In addition, to estimate 
exposure in the 1999 risk assessment, EPA used block-group-level data 
from the 1990 Census. More recent studies use data from the 2000 
Census.
---------------------------------------------------------------------------

    \301\ U.S. EPA, Regulatory Impact Analysis of The Final 
Industrial Boilers and Process Heaters NESHAP: Final Report, 
February 2004.
    \302\ U.S. EPA, Benefits of the Proposed Inter-State Air Quality 
Rule, January 2004.
    \303\ Research Triangle Institute, Human Health and Ecological 
Risk Assessment Support to The Development of Technical Standards 
for Emissions from Combustion Units Burning Hazardous Wastes: 
Background Document, prepared for U.S. EPA, Office of Solid Waste, 
July 1999.
---------------------------------------------------------------------------

    More recent EPA benefits analyses also apply a different 
concentration-response function for PM mortality than that used for the 
1999 risk assessment. In 1999, EPA used the concentration-response 
function published by Pope, et al. in 1995.\304\ Since that time, 
health scientists have refined estimates of the concentration-response 
relationship, and EPA has updated its methodology for estimating 
benefits to reflect these more recent estimates. In the regulatory 
impact analysis of the non-hazardous boiler MACT standards, EPA used 
the Krewski, et al. re-analysis of the 1995 Pope study to estimate 
avoided premature mortality.\305\ Since the relative risk estimated in 
the Krewski study (1.18) is nearly the same as that presented in Pope 
et al. (1.17), the Agency assumes that updating the 1999 risk 
assessment to reflect the results of the 2000 Krewski study would have 
minimal impact on the estimated benefits associated with the proposed 
HWC MACT replacement standards.
---------------------------------------------------------------------------

    \304\ Pope, C.A., III, M.J. Thun, M.M. Namboodiri, D.W. Dockery, 
J.S. Evans, F.E. Speizer, and C.W. Heath, Jr. 1995. Particulate air 
pollution as a predictor of mortality in a prospective study of U.S. 
adults. American Journal of Respiratory and Critical Care 
Medicine151:669-674, as cited in Research Triangle Institute, op. 
cit.
    \305\ Krewski D, Burnett RT, Goldbert MS, Hoover K, Siemiatycki 
J, Jerrett M, Abrahamowicz M, White WH. 2000. Reanalysis of the 
Harvard Six Cities Study and the American Cancer Society Study of 
Particulate Air Pollution and Mortality. Special Report to the 
Health Effects Institute, Cambridge, MA, July 2000.
---------------------------------------------------------------------------

    For the current proposal, we took the avoided incidence estimates 
from the September 1999 final rule and adjusted them to reflect the 
particulate matter emission reductions projected to occur under the 
proposed standards and the reduction in the numbers of facilities 
burning hazardous wastes since the analysis for the final rule was 
completed. For cement kilns, lightweight aggregate kilns, and 
incinerators, the estimates were made by adjusting the respective 
estimates at the source category level by the ratio of emission 
reductions (for today's proposed rule vs. the 1999 final rule) and the 
ratio of the number of facilities affected by the rules (facilities 
currently burning hazardous wastes vs. facilities burning hazardous 
wastes in the analysis for the September 1999 final rule).\306\ For 
liquid and solid fuel-fired boilers and hydrochloric acid production 
furnaces, we extrapolated the avoided incidence from the incinerator 
source category using a similar approach except that the ratios of the 
exposed populations were used (corresponding to the concentration-

[[Page 21353]]

response functions from the 1999 analysis), instead of the number of 
facilities. We estimated the exposed populations for hazardous waste-
burning boilers and hydrochloric acid production furnaces using the 
same GIS methods as the September 1999 final rule (i.e., a 16 sector 
overlay). Nonetheless, the extrapolated estimates are subject to some 
uncertainty. The estimates of avoided incidence of mortality and 
morbidity are shown in Table 2. The estimates of days of restricted 
activity and days of work lost are shown in Table 3.
---------------------------------------------------------------------------

    \306\ To account for the increase in population since the 1990 
census was taken, for the Phase I sources we also adjusted the 
avoided incidence estimates by the ratio of the population at the 
national level (corresponding to the concentration-response 
function) for the year 2000 census vs. the 1990 census. For Phase II 
source, we used the year 2000 census to develop source category-
specific population estimates for use in the extrapolations.

                                            Table 2.--PM-Related Avoided Incidence of Mortality and Morbidity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                        Hospital admissions                         Respiratory                      Illnesses
                                         ---------------------------------------------------------------------------------------------------------------
             Source category                                Respiratory                       Chronic          Acute           Lower           Upper
                                             Mortality        illness     Cardiovascular    bronchitis      bronchitis      respiratory     respiratory
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cement Kilns............................             0.0             0.0             0.0             0.0             0.0             0.1             0.0
Lightweight Aggregate Kilns.............             0.0             0.0             0.0             0.0             0.0             0.0             0.0
Incinerators............................             0.0             0.0             0.0             0.0             0.0             0.0             0.0
Solid Fuel Boilers......................             0.0             0.0             0.0             0.1             0.1             0.7             0.1
HCl Production Furnaces.................             0.0             0.0             0.0             0.0             0.0             0.0             0.0
Liquid Fuel Boilers.....................             0.3             0.9             0.4             5.5             4.2            37.2             4.3
    Total...............................             0.3             0.9             0.4             5.6             4.3            38.0             4.4
--------------------------------------------------------------------------------------------------------------------------------------------------------


                           Table 3.--PM-Related Restricted Activity and Work Loss Days
----------------------------------------------------------------------------------------------------------------
                                                                    Minor          Restricted
                       Source category                            restricted     activity days   Work  loss days
----------------------------------------------------------------------------------------------------------------
Cement Kilns.................................................              3.1              1.0              0.4
Lightweight Aggregate Kilns..................................              0.0              0.0              0.0
Incinerators.................................................              0.0              0.0              0.0
Solid Fuel-Fired Boilers.....................................             59.0             19.4              7.1
HCl Production Furnaces......................................              0.0              0.0              0.0
Liquid Fuel-Fired Boilers....................................           3692.2           1215.9            443.2
                                                              ------------------
    Total....................................................           3754.4           1236.4            450.7
----------------------------------------------------------------------------------------------------------------

    We also conducted an analysis of key factors that influence the PM-
related health benefits by statistically comparing attributes of the 
sources subject to today's proposed rule versus the sources subject to 
the 1999 rule. The greater the similarities between the sources covered 
by today's proposal and the sources subject to the 1999 rule, the more 
confidence we have in the extrapolated incidence estimates. The more 
the dissimilarities, the greater is the uncertainty in the estimates. 
The comparative analysis is discussed in a separate background document 
for today's rule.\307\
---------------------------------------------------------------------------

    \307\ See ``Inferential Risk Analysis in Support of Standards 
for Emissions of Hazardous Air Pollutants from Hazardous Waste 
Combustors,'' prepared under contract to EPA by Research Triangle 
Institute, Research Triangle Park, NC.
---------------------------------------------------------------------------

VIII. What are the Social Costs and Benefits of the Proposed Rule?

    The value of any regulatory action is traditionally measured by the 
net change in social welfare that it generates. Our economic assessment 
for today's rule evaluates compliance costs, social costs, benefits, 
economic impacts, selected other impacts (e.g., children's health, 
unfunded mandates), 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 (results 
discussed above), examined 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. Because 
our data were limited, the findings from these analyses are more 
accurately viewed as national estimates.

A. Combustion Market Overview

    The hazardous waste industry consists of three key segments: 
hazardous waste generators, fuel blenders/intermediaries, and hazardous 
waste burners. Hazardous waste is combusted at four main types of 
facilities: commercial incinerators, on-site incinerators, waste 
burning kilns (cement kilns and lightweight aggregate kilns), and 
industrial boilers. 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 and boilers generally burn hazardous wastes to generate 
heat and power for their manufacturing processes.
    As discussed above, we have identified a total of 276 sources 
(systems) permitted to burn hazardous waste in the United States. 
Liquid fuel-fired boilers account for 107 sources, followed by on-site 
incinerators at 92 sources. Cement kilns, hydrochloric acid production 
furnaces, and commercial incinerators account for 26, 17, and 15 
sources, respectively. Solid fuel-fired boilers and lightweight 
aggregate kilns make up the remaining, at 12 and seven systems, 
respectively. These 276 sources are operated by a total of 150 
different facilities. On-site incinerators account for 69 facilities, 
or 46 percent of this total, followed by all boiler facilities at 45 
percent (67 facilities). There are 14 cement kilns, 10 commercial 
incineration facilities and three lightweight aggregate kilns. A single 
facility may have one or more combustion systems. Facilities with 
multiple systems may have the same or different types. Thus, the 
numbers presented above will not sum to 150 facilities.

[[Page 21354]]

    The number of sources per facility in the combustion universe 
ranges from one to 12. On average, boilers, hydrochloric acid 
production furnaces, and lightweight aggregate kilns, with an average 
of 2.0 sources per facility, contain more waste burning combustion 
systems per facility than do incinerators and cement kilns, with an 
average of 1.4 sources per facility. On-site incinerators, with 1.3 
sources per facility, have the lowest average among all types of 
combustion devices in the universe.
    Combustion systems operating at chemical and allied product 
facilities represent 72 percent (199 sources) of the total number of 
hazardous waste burning systems. Stone, clay, and glass production 
accounts for 12 percent (34 sources), followed by electric, gas, and 
sanitation services at 8 percent (22 sources).
    The EPA Biennial Reporting System (BRS) reports a total demand for 
all combusted hazardous waste, across all facilities, at 3.56 million 
tons (U.S. ton) in 1999. Commercial energy recovery (cement kilns and 
lightweight aggregate kilns) burned about 31 percent of this total, 
followed by on-site incinerators at just over 28 percent, captive 
energy recovery (all boilers) at 28 percent, and commercial 
incineration at nearly 13 percent. About 62 percent of all waste burned 
in 1999 was organic liquids. This is followed by inorganic liquids (15 
percent), sludges (13 percent), and solids (9 percent). Hazardous gases 
represent about 0.1 percent of the total annual quantity burned. In 
terms of waste source, the industrial organic chemicals sector 
generates approximately a third of all hazardous waste burned, followed 
by pesticides and agricultural chemicals, business services, organic 
fibers, medicinal chemicals, pharmaceuticals, plastics materials and 
resins, petroleum, and miscellaneous.
    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, 
lightweight aggregate kilns, and boilers derive heat and energy by 
combining clean burning (solvents and organics) high-Btu liquid 
hazardous wastes \308\ with conventional fuels.
---------------------------------------------------------------------------

    \308\ Many cement kilns are also able to burn a certain level of 
solid waste.
---------------------------------------------------------------------------

    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, system consolidations, and facility closures. Since the 
mid 1990s, several additional combustion facilities have closed, while 
many of those that have remained open have consolidated, or further 
consolidated their operations. Available excess capacity is currently 
estimated at about 20 percent of the total 1999 quantity combusted.

B. 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 proposed rule. The baseline essentially 
describes the world absent the proposed 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. Thus, 
incremental cost and economic impacts are projected beyond the 
standards established in the February 13, 2002, Interim Standards Final 
Rule.

C. Analytical Methodology and Findings--Social Cost Analysis

    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 away from the current market 
equilibrium. 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. The private sector compliance costs of $57.7 million 
to $77.9 million per year, as presented in Section IV, assume no market 
adjustments. These costs may be considered to represent the high-end of 
total social costs. Our best estimate of social costs assume rational 
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.
    For all sectors to meet the proposed replacement standards, total 
annualized market-adjusted costs are estimated to range from $41 to $50 
million. The low end of this range assumes no chlorine control 
costs.\309\ The Phase II sources represent about 83 percent of the 
high-end total. Our economic model indicates that two sectors as a 
whole, commercial incinerators and cement kilns, would experience net 
gains following all market adjustments. This occurs due to marginally 
higher prices,

[[Page 21355]]

increased waste receipts, and relatively low upgrade costs. Total 
annual government costs are approximately one-half million dollars for 
the proposed approach.
---------------------------------------------------------------------------

    \309\ We are proposing using section 112(d)(4) of the Clean Air 
Act to establish risk-based standards for total chlorine for 
hazardous waste combustors (except for hydrochloric acid production 
furnaces). The low-end of this cost range assumes all facilities 
emit total chlorine levels below risk-based levels of concern. Under 
this scenario, no total chlorine controls are assumed to be 
necessary.
---------------------------------------------------------------------------

D. Analytical Methodology and Findings--Benefits Assessment

    This section discusses the monetized and non-monetized benefits to 
human health and the environment potentially associated with today's 
rule. Monetized human health benefits are derived from reductions in PM 
and dioxin/furan exposure and are based on a Value of Statistical Life 
(VSL) estimate of $5.5 million.\10\ Monetized environmental benefits 
are estimated from visibility improvements expected in response to 
reduced air pollution. Non-monetized benefits are associated with human 
health, ecological, and waste minimization factors.
---------------------------------------------------------------------------

    \310\ Office of Management and Budget. Circular A-4. September 
17, 2003.
---------------------------------------------------------------------------

1. Monetized Benefits
    Particulate Matter--We developed monetized estimates of human 
health benefits associated with reduced emissions of particulate matter 
(PM). We also estimated the value of improved visibility associated 
with reduced PM emissions.
    Results from our risk assessment extrapolation procedure, as 
discussed under Section VII above, are used to evaluate incremental 
human health benefits potentially associated with particulate matter 
emission reductions at hazardous waste combustion facilities. This 
analysis used avoided cost factors from the July 1999 Assessment 
document, combined with the updated estimates of avoided adverse health 
effects related only to particulate matter emissions.
    Under the Agency preferred approach, reduced PM emissions are 
estimated to result in monetized human health benefits of approximately 
$4.18 million per year. This is an undiscounted figure. Avoided PM 
morbidity cases account for $2.34 million of this total and include: 
respiratory illness, cardiovascular disease, chronic bronchitis, work 
loss days, and minor restricted activity. Chronic bronchitis accounts 
for approximately 90 percent of the total morbidity cases. All 
morbidity cases are assumed to be avoided within the first year 
following reduced PM emissions and are not discounted under any 
scenario.
    Avoided premature deaths (mortality) account for the remaining 
$1.84 million per year. Assuming a discount rate of three and seven 
percent, PM mortality benefits would be $1.70 million and $1.54 
million, respectively. Our discounted analysis of PM mortality benefits 
assumes that 25 percent of premature mortalities occur during the first 
year, 25 percent occur during the second year, and 16.7 percent occur 
in each of the three subsequent years after exposure. This methodology 
is consistent with the Agency's analysis of the proposed Clear Skies 
Act of 2003. Total monetized PM benefits, therefore, are estimated to 
range from $4.24 million/year to $4.52 million per year. These findings 
appear to indicate that particulate matter reductions from the interim 
baseline to the replacement standards are small relative to the 
reductions achieved in going to the interim standards. This assessment 
does not consider corresponding health benefits associated with the 
reduction of metals carried by the PM.
    Dioxin/furan--Dioxin/furan emissions are projected to be reduced by 
a total of 4.68 grams per year under the Agency Preferred Approach. Of 
this total, 0.42 grams/year are derived in going from the interim 
standards baseline to the floor levels. The remaining 4.26 grams/year 
are derived by going from the floor to beyond-the-floor (BTF) 
standards. In the July 23, 1999 Addendum to the Assessment, cancer risk 
reductions linked to consumption of dioxin-contaminated agricultural 
products accounted for the vast majority of the 0.36 cancer cases per 
year that were expected to be avoided due to the 1999 standards. Cancer 
risk reductions associated with the replacement standards are expected 
to be less than 0.36 cases per year, but greater than zero.
    Assuming that the proportional relationship between dioxin/furans 
emissions and premature cancer deaths is constant, we estimate that 
approximately 0.058 premature cancer deaths will be avoided on an 
annual basis under the Agency Preferred Approach because of reduced 
dioxin/furans emissions. This estimate reflects a cancer risk slope 
factor of 1.56 x 105 [mg/kg/day]-1. This cancer 
slope factor is derived from the Agency's 1985 health assessment 
document for polychlorinated dibenzo-p-dioxins \311\ and represents an 
upper bound 95th percentile confidence limit of the excess cancer risk 
from a lifetime exposure.
---------------------------------------------------------------------------

    \311\ USEPA, 1985. Health Assessment Document for 
Polychlorinated Dibenzo-p-Dioxins. EPA/600/8-84/014F. Final Report. 
Office of Health and Environmental Assessment. Washington, DC. 
September, 1985.
---------------------------------------------------------------------------

    For the past 12 years the Agency has been conducting a reassessment 
of the human health risks associated with dioxin and dioxin-like 
compounds. This reassessment \312\ will soon be under review at the 
National Academy of Sciences (NAS), as specified by Congress in the 
Conference Report accompanying EPA's fiscal year 2003 appropriation 
(Title IV of Division K of the Conference Report for the Consolidated 
Appropriations Resolution of 2003). Evidence compiled from this draft 
reassessment indicates that the carcinogenic effects of dioxin/furans 
may be six times as great as believed in 1985, reflecting an upper 
bound cancer risk slope factor of 1 x 106 [mg/kg/day]-1 for 
some individuals. Agency scientists' more likely (central tendency) 
estimates (derived from the ED01 rather than the 
LED01) result in slope factors and risk estimates that are 
within 2-3 times of the upper bound estimates (i.e., between 3 x 
105 [mg/kg/day]-1 and 5 x 105 [mg/kg/
day]-1) based on the available epidemiological and animal 
cancer data. Risks could be as low as zero for some individuals. Use of 
the alternative upper bound cancer risk slope factor would result in up 
to 0.35 premature cancer deaths avoided in response to the proposed 
replacement standards for dioxin/furans. The assessment of upper bound 
cancer risk using this alternative slope factor should not be 
considered Agency policy. The proposed standards for dioxin in today's 
rule were not based on this draft reassessment.
---------------------------------------------------------------------------

    \312\ U.S.EPA, Exposure and Human Health Reassessment of 
2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds, 
September 2000. Note: Toxicity risk factors presented in this 
document should not be considered EPA's official estimate of dioxin 
toxicity, but rather reflect EPA's ongoing effort to reevaluate 
dioxin toxicity.
---------------------------------------------------------------------------

    Total non-discounted human health benefits associated with 
projected dioxin reductions are estimated at $0.32 million/year. Total 
benefits are estimated to range from $0.12 million/year to $0.17 
million/year at a 3 percent discount rate, and $0.03 million/year to 
$0.08 million/year at a 7 percent rate. The two figures under each 
discount scenario reflect an assumed latency period of 21 or 34 years.
    Visibility Benefits--In addition to the human health benefits 
discussed above, we also assessed visibility improvements. Particulate 
matter emissions are a primary cause of reduced visibility. Changes in 
the level of ambient particulate matter caused by the reduction in 
emissions associated with the Agency preferred approach are expected to 
increase the level of visibility in some parts of the United States. We 
derived upper and lower bound benefits estimates associated with 
particulate matter emissions

[[Page 21356]]

reductions using two different methodologies, each comparing reductions 
to those associated with the Clean Air Act. The first approach assumes 
a linear relationship between particulate matter reductions and 
visibility improvements. Under this approach, the Agency preferred 
replacement standards may result in a visibility benefit of 
approximately $5.78 million per year. Our second approach is to assume 
a linear relationship between health benefits and visibility benefits 
associated with reduction in particulate matter emissions. Under this 
approach, the proposed replacement standards could result in a 
visibility benefit of approximately $0.11 million/year. This method 
represents our lower bound estimate of visibility benefits.
2. Non-Monetized Benefits
    We examined, but did not monetize human health benefits potentially 
associated with reduced exposure to lead, mercury, and total chlorine. 
Non monetized ecological benefits potentially associated with 
reductions in dioxin/furan, selected metals, total chlorine, and 
particulate matter were also examined. Finally, waste minimization is 
examined as a non-monetized benefit.
    Lead--The proposed replacement standards are expected to reduce 
lead emissions by approximately five tons per year. In comparison, the 
1999 standards were expected to reduce lead emissions by 89 tons per 
year, and were expected to reduce cumulative lead exposures for two 
children age 0-5 to less than 10 [mu]g/dL. The lead benefits associated 
with the proposed replacement standards are therefore expected to be 
modest, reducing the cumulative lead exposures for less than two 
children age 0-5, less than 10 [mu]g/dL annually. The proposed 
replacement standards will also result in reduced lead levels for 
children of sub-populations with especially high levels of exposure. 
Children of subsistence fishermen, commercial beef farmers, and 
commercial dairy farmers who face the greatest levels of cumulative 
lead exposure will also experience comparable reductions in overall 
exposure as a result of the MACT standards.
    Mercury--Mercury emitted from hazardous waste burning incinerators, 
kilns, boilers, and other natural and man-made sources is carried by 
winds through the air and eventually is deposited to water and land. 
Recent estimates (which are highly uncertain) of annual total global 
mercury emissions from all sources (natural and anthropogenic) are 
about 5,000 to 5,500 tons per year (tpy). Of this total, about 1,000 
tpy are estimated to be natural emissions and about 2,000 tpy are 
estimated to be contributions through the natural global cycle of re-
emissions of mercury associated with past anthropogenic activity. 
Current anthropogenic emissions account for the remaining 2,000 tpy. 
Point sources such as fuel combustion; waste incineration; industrial 
processes; and metal ore roasting, refining, and processing are the 
largest point source categories on a world-wide basis. Given the global 
estimates noted above, U.S. anthropogenic mercury emissions are 
estimated to account for roughly 3 percent of the global total, and 
U.S. hazardous waste burning incinerators, kilns, and boilers are 
estimated to account for about 0.0045 percent of total global 
emissions.
    Mercury exists in three forms: elemental mercury, inorganic mercury 
compounds (primarily mercuric chloride), and organic mercury compounds 
(primarily methylmercury). Mercury is usually released in an elemental 
form and later converted into methylmercury by bacteria. Methylmercury 
may be more toxic to humans than other forms of mercury, in part 
because it is more easily absorbed in the body.\313\ If the deposition 
is directly to a water body, then the processes of aqueous fate, 
transport, and transformation begin. If deposition is to land, then 
terrestrial fate and transport processes occur first and then aqueous 
fate and transport processes occur once the mercury has cycled into a 
water body. In both cases, mercury may be returned to the atmosphere 
through resuspension. In water, mercury is transformed to methylmercury 
through biological processes and for exposures affected by this 
rulemaking. Methylmercury is considered to be the form of greatest 
concern. Once mercury has been transformed into methylmercury, it can 
be ingested by the lower trophic level organisms where it can 
bioaccumulate in fish tissue (i.e., concentrations of mercury remain in 
the fish's system for a long period of time and accumulates in the fish 
tissue as predatory fish consume other species in the food chain). Fish 
and wildlife at the top of the food chain can, therefore, have mercury 
concentrations that are higher than the lower species, and they can 
have concentrations of mercury that are higher than the concentration 
found in the water body itself. In addition, when humans consume fish 
containing methylmercury, the ingested methylmercury is almost 
completely absorbed into the blood and distributed to all tissues 
(including the brain); it also readily passes through the placenta to 
the fetus and fetal brain.\314\
---------------------------------------------------------------------------

    \313\ Regulatory Impact Analysis of the Final Industrial Boilers 
and Process Heaters NESHAP: Final Report, February 2004.
    \314\ Regulatory Impact Analysis of the Final Industrial Boilers 
and Process Heaters NESHAP: Final Report, February 2004.
---------------------------------------------------------------------------

    Based on the findings of the National Research Council, EPA has 
concluded that benefits of Hg reductions would be most apparent at the 
human consumption stage, as consumption of fish is the major source of 
exposure to methylmercury. At lower levels, documented Hg exposure 
effects may include more subtle, yet potentially important, 
neurodevelopmental effects.
    Some subpopulations in the U.S., such as: Native Americans, 
Southeast Asian Americans, and lower income subsistence fishers, may 
rely on fish as a primary source of nutrition and/or for cultural 
practices. Therefore, they consume larger amounts of fish than the 
general population and may be at a greater risk to the adverse health 
effects from Hg due to increased exposure. In pregnant women, 
methylmercury can be passed on to the developing fetus, and at 
sufficient exposure may lead to a number of neurological disorders in 
children. Thus, children who are exposed to low concentrations of 
methylmercury prenatally may be at increased risk of poor performance 
on neurobehavioral tests, such as those measuring attention, fine motor 
function, language skills, visual-spatial abilities (like drawing), and 
verbal memory. The effects from prenatal exposure can occur even at 
doses that do not result in effects in the mother. Mercury may also 
affect young children who consume fish containing mercury. Consumption 
by children may lead to neurological disorders and developmental 
problems, which may lead to later economic consequences.
    In response to potential risks of mercury-containing fish 
consumption, EPA and FDA have issued fish consumption advisories which 
provide recommended limits on consumption of certain fish species for 
different populations. EPA and FDA have developed a new joint advisory 
that was released in March 2004. This new FDA-EPA fish advisory 
recommends that women and young children reduce the risks of Hg 
consumption in their diet by moderating their fish consumption, 
diversifying the types of fish they consume, and by checking any local 
advisories that may exist for local rivers and streams. This 
collaborative FDA-EPA effort will greatly assist in

[[Page 21357]]

educating the most susceptible populations. Additionally, the 
reductions of Hg from this regulation may potentially lead to fewer 
fish consumption advisories (both from federal or state agencies), 
which will benefit the fishing community. Currently 44 states have 
issued fish consumption advisories for non-commercial fish for some or 
all of their waters due to contamination of mercury. The scope of FCA 
issued by states varies considerably, with some warnings applying to 
all water bodies in a state and others applying only to individual 
lakes and streams. Note that the absence of a state advisory does not 
necessarily indicate that there is no risk of exposure to unsafe levels 
of mercury in recreationally caught fish. Likewise, the presence of a 
state advisory does not indicate that there is a risk of exposure to 
unsafe levels of mercury in recreationally caught fish, unless people 
consume these fish at levels greater than those recommended by the fish 
advisory.
    Reductions in methylmercury concentrations in fish should reduce 
exposure, subsequently reducing the risks of mercury-related health 
effects in the general population, to children, and to certain 
subpopulations. Fish consumption advisories (FCA) issued by the States 
may also help to reduce exposures to potential harmful levels of 
methylmercury in fish. To the extent that reductions in mercury 
emissions reduces the probability that a water body will have a FCA 
issued, there are a number of benefits that will result from fewer 
advisories, including increased fish consumption, increased fishing 
choices for recreational fishers, increased producer and consumer 
surplus for the commercial fish market, and increased welfare for 
subsistence fishing populations.
    There is a great deal of variability among individuals in fish 
consumption rates; however, critical elements in estimating 
methylmercury exposure and risk from fish consumption include the 
species of fish consumed, the concentrations of methylmercury in the 
fish, the quantity of fish consumed, and how frequently the fish is 
consumed. The typical U.S. consumer eating a wide variety of fish from 
restaurants and grocery stores is not in danger of consuming harmful 
levels of methylmercury from fish and is not advised to limit fish 
consumption. Those who regularly and frequently consume large amounts 
of fish, either marine or freshwater, are more exposed. Because the 
developing fetus may be the most sensitive to the effects from 
methylmercury, women of child-bearing age are regarded as the 
population of greatest interest. The EPA, Food and Drug Administration, 
and many States have issued fish consumption advisories to inform this 
population of protective consumption levels.
    The EPA's 1997 Mercury Study RTC supports a plausible link between 
anthropogenic releases of Hg from industrial and combustion sources in 
the U.S. and methylmercury in fish. However, these fish methylmercury 
concentrations also result from existing background concentrations of 
Hg (which may consist of Hg from natural sources, as well as Hg which 
has been re-emitted from the oceans or soils) and deposition from the 
global reservoir (which includes Hg emitted by other countries). Given 
the current scientific understanding of the environmental fate and 
transport of this element, it is not possible to quantify how much of 
the methylmercury in locally-caught fish consumed by the U.S. 
population is contributed by U.S. emissions relative to other sources 
of Hg (such as natural sources and re-emissions from the global pool). 
As a result, the relationship between Hg emission reductions from Phase 
I and Phase II sources assessed in this rule, and methylmercury 
concentrations in fish cannot be calculated in a quantitative manner 
with confidence. In addition, there is uncertainty regarding over what 
time period these changes would occur.
    Given the present understanding of the Hg cycle, the flux of Hg 
from the atmosphere to land or water at one location is comprised of 
contributions from: the natural global cycle; the cycle perturbed by 
human activities; regional sources; and local sources. Recent advances 
allow for a general understanding of the global Hg cycle and the impact 
of the anthropogenic sources. It is more difficult to make accurate 
generalizations of the fluxes on a regional or local scale due to the 
site-specific nature of emission and deposition processes. Similarly, 
it is difficult to quantify how the water deposition of Hg leads to an 
increase in fish tissue levels. This will vary based on the specific 
characteristics of the individual lake, stream, or ocean.
    Total Chlorine--We were not able to quantify the benefits 
associated with reductions in total chlorine emissions. Total chlorine 
is a combination of hydrogen chloride and chlorine gas. The replacement 
standards proposed today are expected to reduce total chlorine 
emissions by 2,638 tons. Hydrogen chloride is corrosive to the eyes, 
skin, and mucous membranes. Acute inhalation can cause eye, nose, and 
respiratory tract irritation and inflamation, and pulmonary edema. 
Chronic occupational inhalation has been reported to cause gastritis, 
bronchitis, and dermatitis in workers. Long term exposure can also 
cause dental discoloration and erosion. No information is available on 
the reproductive or developmental effects in humans. Chlorine gas 
inhalation can cause bronchitis, asthma and swelling of the lungs, 
headaches, heart disease, and meningitis. Acute exposure causes more 
severe respiratory and lung effects, and can result in fatalities in 
extreme cases. No information is available on the reproductive or 
developmental effects in humans. The proposed replacement standards are 
expected to reduce chlorine exposure for people in close proximity to 
hazardous waste combustion facilities, and are therefore likely to 
reduce the risk of all associated health effects.
    Ecological Benefits--We examined ecological benefits through a 
comparison of the 1999 Assessment and the proposed replacement 
standards. Ecological benefits in the 1999 Assessment were based on 
reductions of approximately 100 tons per year in dioxin/furans and 
selected metals. Lead was the only pollutant of concern for aquatic 
ecosystems, while mercury appeared to be of greatest concern for 
terrestrial ecosystems. Dioxin/furan and lead emission reductions also 
provided some potential benefits for terrestrial ecosystems. The 
proposed replacement standards are expected to reduce dioxin/furan and 
selected metal emissions by about 15 to 20 percent of the 1999 
estimate. The proposed replacement standards will produce fewer 
incremental benefits than those estimated for the 1999 Assessment (and 
later, for the 2002 Interim Standards). However, the 1999 Assessment 
did not estimate the ecological benefits of MACT standards for 
industrial boilers and industrial furnaces. These systems were excluded 
from the universe in 1999 but are part of the universe addressed by the 
proposed replacement standards. As a result, while the total ecological 
benefits of the proposed rule are likely to be modest, areas near 
facilities with boilers may enjoy more significant ecological benefits 
under the proposed replacement standards than areas near facilities 
that have already complied with the 2002 Interim standards.
    Mercury, lead, and chlorides are among the HAPs that can cause 
damage to the health and visual appearance of

[[Page 21358]]

plants.\315\ While the total value of forest health is difficult to 
estimate, visible deterioration in the health of forests and plants can 
cause a measurable change in recreation behavior. Several studies that 
measure the change in outdoor recreation behavior according to forest 
health are available to place a value on aesthetic degradation of 
forests.\316\ Although these studies are available, additional research 
is needed to fully understand the effects of these HAPs on the forest 
ecosystem. Thus, these benefits are not quantified in this analysis.
---------------------------------------------------------------------------

    \315\ Although the primary pollutants which are detrimental to 
vegetation aesthetics and growth are tropospheric ozone, sulfur 
dioxide, and hydrogen fluoride, three pollutants which are not 
regulated in the MACT standards, some literature exists on the 
relationship between metal deposition and vegetation health. 
(Mercury Study Report to Congress Volume VI, 1997) (Several studies 
are cited in this report.)
    \316\ See, for example, Brown, T.C. et al. 1989, Scenic Beauty 
and Recreation Value: Assessing the Relationship, In J. Vining, ed., 
Social Science and Natural Resources Recreation Management, Westview 
Press, Boulder, Colorado; this work studies the relationship between 
forest characteristics and the value of recreational participation. 
Also see Peterson, D.G. et al. 1987, Improving Accuracy and Reducing 
Cost of Environmental Benefit Assessments. Draft Report to the U.S. 
EPA, by Energy and Resource Consultants, Boulder, Colorado; Walsh et 
al. 1990, Estimating the public benefits of protecting forest 
quality, Journal of Forest Management, 30:175-189., and Homes et al. 
1992, Economic Valuation of Spruce-Fir Decline in the Southern 
Appalachian Mountains: A comparison of Value Elicitation Methods. 
Presented at the Forestry and the Environment: Economic Perspectives 
Conference, March 9-11, 1992 Jasper, Alberta, Canada for estimates 
of the WTP of visitors and residents to avoid forest damage.
---------------------------------------------------------------------------

    Emissions that are sufficient to cause structural and aesthetic 
damage to vegetation are likely to affect growth as well. Little 
research has been done on the effects of compounds such as chlorine, 
heavy metals (as air pollutants), and PM on agricultural 
productivity.\317\ Even though the potential for visible damage and 
production decline from metals and other pollutants suggests the 
proposed replacement standards could increase agricultural 
productivity, these changes cannot be quantified.
---------------------------------------------------------------------------

    \317\ MacKenzie, James J., and Mohamed T. El-Ashry, Air 
Pollution's Toll on Forests and Crops (New Haven, Yale University 
Press, 1989).
---------------------------------------------------------------------------

3. Waste Minimization Benefits
    Facilities that burn hazardous waste and remain in operation 
following implementation of the replacement standards are expected to 
experience marginally increased costs as a result of the MACT 
standards. This will result in an incentive to pass these increased 
costs on to their customers in the form of higher combustion prices. In 
the 1999 Assessment we conducted a waste minimization analysis to 
inform the expected price change. The analysis concluded that the 
demand for combustion is relatively inelastic. While a variety of waste 
minimization alternatives are available for managing hazardous waste 
streams that are currently combusted, the costs of these alternatives 
generally exceed the cost of combustion. When the additional costs of 
compliance with the MACT standards are taken into account, waste 
minimization alternatives still tend to exceed the higher combustion 
costs. This inelasticity suggests that, in the short term, large 
reductions in waste quantities are not likely. However, over the longer 
term (i.e., as production systems are updated), companies may continue 
to seek alternatives to expensive waste-management (i.e., source 
reduction). To the extent that increases in combustion prices provide 
additional incentive to adopt more efficient processes, the proposed 
replacement standards may contribute to the longer term process based 
waste minimization efforts.
    No waste minimization impacts are captured in our quantitative 
analysis of costs and benefits. A quantitative assessment of the 
benefits associated with waste minimization may result in double-
counting of some of the benefits described earlier. For example, waste 
minimization may reduce emissions of hazardous air pollutants and 
therefore have a positive effect on public health. Furthermore, 
emission reductions beyond those necessary for compliance with the 
replacement standards are not addressed in the benefits assessment. In 
addition, waste minimization is likely to result in specific types of 
benefits not captured in this Assessment. For example, waste generators 
that engage in waste minimization may experience a reduction in their 
waste handling costs and could also reduce the risk related to waste 
spills and waste management. Finally, waste minimization procedures 
potentially stimulated by today's action, as proposed, may result in 
additional costs to facilities that implement these technologies. These 
have not been assessed in our analysis but are likely to at least 
partially offset corresponding benefits.
4. Conclusion
    Total non-discounted monetized benefits are estimated to range from 
$$4.6 million/year to $10.3 million/year. It is important to emphasize 
that monetized benefits represent only a portion of the total benefits 
associated with this rule. A significant portion of the benefits are 
not monetized. Specifically, ecological benefits, and human health 
benefits associated with reductions in chlorine, mercury, and lead are 
not quantified or monetized. In some locations these benefits may be 
significant. In addition, specific sub-populations near combustion 
facilities, including children and minority populations, may be 
disproportionately affected by environmental risks and may therefore 
enjoy more significant benefits. For a complete discussion of the 
methodology, data, findings, and limitations associated with our 
benefits analysis the reader is encouraged to review the Assessment and 
Addendum documents, as identified under Part Five, Section I.

IX. How Does the Proposed Rule Meet the RCRA Protectiveness Mandate?

    As discussed in more detail below, we believe today's proposed 
standards, based on evaluating estimated emissions from sources, are 
generally protective. We therefore propose that these standards apply 
in lieu of RCRA air emission standards in most instances.

A. Background

    Section 3004(a) of RCRA requires the Agency to promulgate standards 
for hazardous waste treatment, storage, and disposal facilities as 
necessary to protect human health and the environment. The standards 
for hazardous waste incinerators generally rest on this authority. In 
addition, section 3004(q) requires the Agency to promulgate standards 
for emissions from facilities that burn hazardous waste fuels (e.g., 
cement and lightweight aggregate kilns, boilers, and hydrochloric acid 
production furnaces) as necessary to protect human health and the 
environment. Using RCRA authority, the Agency has historically 
established emission (and other) standards for hazardous waste 
combustors that are either entirely risk-based (e.g., site-specific 
standards for metals under the Boiler and Industrial Furnace rule), or 
are technology-based but determined by a generic risk assessment to be 
protective (e.g., the DRE standard for incinerators and BIFs).
    The MACT standards proposed today implement the technology-based 
regime of CAA section 112. There is, however, a residual risk component 
to air toxics standards. Section 112(f) of the Clean Air Act requires 
the Agency to impose, within eight years after promulgation of the 
technology-based standards promulgated under section 112(d) (i.e., the 
authority for today's proposed standards), additional controls if 
needed to protect public health with an ample

[[Page 21359]]

margin of safety or to prevent adverse environmental effect.
    RCRA section 1006 directs that EPA ``integrate all provisions of 
[RCRA] for purposes of administration and enforcement and . . . avoid 
duplication, to the maximum extent possible, with the appropriate 
provisions of the Clean Air Act. . . .'' Thus, although considerations 
of risk are not ordinarily part of the MACT process, in order to avoid 
duplicative standards where possible, we have evaluated the 
protectiveness of the standards proposed today.
    As noted above, under RCRA, EPA must promulgate standards ``as may 
be necessary to protect human health and the environment.'' RCRA 
section 3004(a) and (q). Technology-based standards developed under CAA 
section 112 do not automatically satisfy this requirement, but may do 
so in fact. See 59 FR at 29776 (June 6, 1994) and 60 FR at 32593 (June 
23, 1995) (RCRA regulation of secondary lead smelter emissions 
unnecessary at this time given stringency of technology-based standard 
and pendency of section 112(f) determination). If the MACT standards, 
as a factual matter, are sufficiently protective to also satisfy the 
RCRA mandate, then no independent RCRA standards are required. 
Conversely, if MACT standards are inadequate, the RCRA authorities 
would have to be used to fill the gap.

B. Assessment of Risks

    The Agency has conducted an evaluation, for the purposes of 
satisfying the RCRA statutory mandates, of the degree of protection 
afforded by the MACT standards being proposed today. We have not 
conducted a comprehensive risk assessment for this proposal; however, a 
comprehensive risk assessment for incinerators, cement kilns, and 
lightweight aggregate kilns was conducted for the 1999 MACT rule. For 
this proposed rule, we are instead comparing characteristics of the 
sources covered by the 1999 rule to the sources covered by the 
replacement rule that are related to risk (e.g., emissions\318\, stack 
characteristics, meteorology, and population). In the 1999 rule we 
concluded that the promulgated standards were sufficiently protective 
and the existing RCRA standards for incinerators, cement kilns, and 
lightweight aggregate kilns need not be retained. Based on the results 
of statistical comparisons, we infer whether risks for incinerators, 
cement kilns, lightweight aggregate kilns, boilers, and hydrochloric 
acid production furnaces will be about the same, less than, or greater 
than the risks estimated for the 1999 rule. We think the comparative 
analysis lends additional support to our view regarding the 
protectiveness of the proposed standards.\319\
---------------------------------------------------------------------------

    \318\ We estimated emissions for each facility based on site-
specific stack gas concentrations and flow rates measured during 
trial burn or compliance tests. For sources where stack gas 
measurements were unavailable, data were imputed by random selection 
from a pool of measurements for similar units. We assumed that 
sources would design their systems to meet an emission level below 
the proposed standard. (In the case of dioxin/furan for sources that 
would not be subject to a numerical emission standard, we assumed 
liquid boilers without dry air pollution control systems and solid 
fuel-fired boilers were emitting at their baseline emissions level 
as portrayed in the data base.) We called this the ``design level.'' 
If available test data in our data base indicate that the source was 
emitting below the design level, we assumed that the source would 
continue to emit at the levels measured in test. For sources 
emitting above the design level of a standard, we assumed they would 
need to reduce emissions to the design level. In the 1999 rule, the 
design level was taken as 70% of the standard. For today's proposed 
standards, the design level is generally the lower of: (1) 70% of 
the standard; or (2) the arithmetic average of the emissions data of 
the best performing sources.
    \319\ See ``Inferential Risk Analysis in Support of Standards 
for Emissions of Hazardous Air Pollutants from Hazardous Waste 
Combustors,'' prepared under contract to EPA by Research Triangle 
Institute, Research Triangle Park, NC.
---------------------------------------------------------------------------

    We believe today's proposed standards provide a substantial degree 
of protection to human health and the environment. We therefore do not 
believe that we need to retain the existing RCRA standards for boilers 
and hydrochloric acid production furnaces (just as we found that 
existing RCRA standards for incinerators, cement kilns, and lightweight 
aggregate kilns were no longer needed after the 1999 rule). However, as 
previously discussed in more detail in Part Two, Section XVII.D, site-
specific risk assessments may be warranted on an individual source 
basis to ensure that the MACT standards provide adequate protection in 
accordance with RCRA.

Part Five: Administrative Requirements

I. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order 12866 [58 FR 51735 (October 4, 1993)], the 
Agency 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 or 
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 entitlements, 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 
the Executive Order.
    Pursuant to the terms of Executive Order 12866, it has been 
determined that this rule is a ``significant regulatory action'' 
because this action may raise novel legal or policy issues due to the 
standards development methodology applied in development of the 
proposed replacement standards. 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.
    The aggregate annualized social costs for this rule are under $100 
million (ranging from $41 to $50 million/yr). We have prepared an 
economic assessment in support of today's action. This document is 
entitled: Assessment of the Potential Costs, Benefits, and Other 
Impacts of the Hazardous Waste Combustion MACT Replacement Standards--
Proposed Rule, March 2004. This Assessment is designed to adhere to 
analytical requirements established under Executive Order 12866, and 
corresponding Agency and OMB guidance; subject to data, analytical, and 
resource limitations. An Addendum entitled: Addendum to the Assessment 
of the Potential Costs, Benefits, and Other Impacts of the Hazardous 
Waste Combustion MACT Replacement Standards--Proposed Rule, March 2004, 
has also been prepared. This Addendum addresses belated changes made to 
the final proposed standards that were not captured in the Assessment. 
The RCRA docket established for today's rulemaking maintains a copy of 
the Assessment and Addendum documents for public review. Interested 
persons are encouraged to read both documents for a full understanding 
of the analytical methodology, findings, and limitations associated 
with this report. Comments and supporting data are encouraged and 
welcomed.

II. Paperwork Reduction Act

    The information collection requirements in this proposed rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the Paperwork Reduction

[[Page 21360]]

Act, 44 U.S.C. 3501 et seq. The Information Collection Request (ICR) 
document prepared by EPA has been assigned EPA ICR number 1773.07.
    EPA is proposing today's regulations under section 112 of the CAA, 
to protect and enhance the quality of our nation's air resources, and 
to promote public health and welfare and the productive capacity of the 
population. See CAA section 101(b)(1). To this end, CAA sections 112(a) 
and (d) direct EPA to set standards for stationary sources emitting the 
hazardous air pollutants. The records and reports required by the 
information collection under this proposal will be used to show 
compliance with the requirements of the rule. EPA believes that if 
these minimum requirements specified under the regulations are not met, 
EPA will not fulfill its Congressional mandate to protect public health 
and the environment.
    The information collection required under this ICR is mandatory for 
the regulated sources as it is essential to properly enforce the 
emission limitation requirements of the rule and will be used to 
further the proper performance of the functions of EPA. EPA has made 
extensive efforts to integrate the monitoring, compliance testing and 
recordkeeping requirements of the CAA and RCRA, so that the burden on 
the sources is kept to a minimum, and the facilities are able to avoid 
duplicate and unnecessary submissions. We also ensure, to the fullest 
extent of the law, the confidentiality of the submitted information.
    The projected annual burden under today's proposal is estimated at 
70,199 hours at a total cost of $5.1 millions. For the hour burden, we 
estimate a total of 2,612 responses from 243 respondents, or an average 
of 27 hours per response, or 289 hours per respondent. The cost burden 
to respondents or recordkeepers resulting from the collection of 
information includes a total capital and start-up cost component, a 
total operation and maintenance component and a purchase of services 
component. The capital and start-up cost component is estimated at 
$36,184 annualized over its expected useful life, and the operation and 
maintenance component is estimated at $488,947 annualized over its 
expected useful life. The frequency of different responses varies and 
is monthly or annually for some and on occasion for others.
    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 in 40 CFR are listed in 40 CFR part 9.
    To comment on the Agency's need for this information, the accuracy 
of the provided burden estimates, and any suggested methods for 
minimizing respondent burden, including the use of automated collection 
techniques, EPA has established a public docket for this rule, which 
includes this ICR, under Docket ID number RCRA-2003-0016. Submit any 
comments related to the ICR for this proposed rule to EPA and OMB. See 
Addresses section at the beginning of this notice for where to submit 
comments to EPA. Send comments to OMB at the Office of Information and 
Regulatory Affairs, Office of Management and Budget, 725 17th Street, 
NW., Washington, DC 20503, Attention: Desk Office for EPA. Since OMB is 
required to make a decision concerning the ICR between 30 and 60 days 
after April 20, 2004, a comment to OMB is best assured of having its 
full effect if OMB receives it by May 20, 2004. The final rule will 
respond to any OMB or public comments on the information collection 
requirements contained in this proposal.

III. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) as amended by the Small 
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 U.S.C. 
601 et seq. 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. This analysis must be completed unless the agency is 
able to certify 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 small 
entity impacts. 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 North American Industrial Classification System (NAICS) code 
by the Small Business Administration.
    Affected individual waste combustors (incinerators, cement kilns, 
lightweight aggregate kilns, solid and liquid fuel-fired boilers, and 
hydrochloric acid production furnaces) will bear the impacts of today's 
rule. These units will incur direct economic impacts as a result of 
today's rule. Few of the hazardous waste combustion facilities affected 
by this proposed rule were found to be owned by small businesses, as 
defined by the Small Business Administration (SBA). From our universe 
of 150 facilities, we identified six facilities that are currently 
owned by small businesses. Three of these are liquid boilers, one is an 
on-site incinerator, one is a cement kiln, and one is an LWAK. 
Annualized economic impacts of the proposed replacement standards were 
found to range from 0.01 percent to 2.23 percent of gross annual 
corporate revenues. Economic impacts to five of the companies were 
found to be less than one percent, while the sixth company was found to 
experience potential impacts between one and 3 percent (2.23 percent). 
These findings reflect worst-case cost estimates under the Agency 
Preferred Approach. Actual economic impacts are likely to be less as 
market adjustments take effect (see appendix H of the Assessment and 
Assessment of Small Entity Impacts in the Addendum).
    Based on the above findings we believe that one small company with 
potential impacts between one and 3 percent of gross revenues does not 
reflect a significant economic impact on a substantial number of 
potentially affected small entities. Therefore, after considering the 
economic impacts of today's proposed rule on small entities, I certify 
that this action will not have a significant economic impact on a 
substantial number of small entities. The reader is encouraged to 
review and comment on our regulatory flexibility screening analysis 
prepared in support of this determination: Regulatory Flexibility 
Screening Analysis for the Proposed Hazardous Waste Combustion MACT 
Replacement Standards. This

[[Page 21361]]

document is incorporated as Appendix H of the Assessment document.

IV. Unfunded Mandates Reform Act

    Signed into law on March 22, 1995, the Unfunded Mandates Reform Act 
(UMRA) calls on all 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.
    Today's proposed 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 cost for today's 
rule is estimated to range from $41 to $50 million.

V. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' is defined in the 
Executive Order to include regulations that have ``substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government.''
    Under Executive Order 13132, EPA may not issue a regulation that 
has federalism implications, that imposes substantial direct compliance 
costs, and that is not required by statute, unless the Federal 
government provides the funds necessary to pay the direct compliance 
costs incurred by State and local governments, or EPA consults with 
State and local officials early in the process of developing the 
proposed regulation.
    This proposed rule does not have federalism implications. It will 
not have substantial direct effects on the States, on the relationship 
between the national government and the States, or on the distribution 
of power and responsibilities among the various levels of government, 
as specified in the Order. The proposed rule focuses on requirements 
for facilities burning hazardous waste, without affecting the 
relationships between Federal and State governments. Thus, Executive 
Order 13132 does not apply to this rule. Although section 6 of 
Executive Order 13132 does not apply to this rule, EPA did include 
three State representatives on our Agency workgroup. These 
representatives participated in the development of this proposed rule. 
State officials were contacted concerning the methodology used in 
standards development.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between EPA and State and local 
governments, EPA specifically solicits comment on this proposed rule 
from State and local officials.

VI. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    Executive Order 13175 \320\: Consultation and Coordination with 
Indian Tribal Governments (65 FR 67249, November 9, 2000), requires EPA 
to develop an accountable process to ensure ``meaningful and timely 
input by tribal officials in the development of regulatory policies 
that have tribal implications.'' Our Agency workgroup for this 
rulemaking includes Tribal representation. We have determined that this 
rule, as proposed, does not have tribal implications, as specified in 
the Order. No Tribal governments are known to own or operate hazardous 
waste combustors subject to the requirements of this proposed rule. 
Furthermore, this proposed rule focuses on requirements for all 
regulated sources without affecting the relationships between tribal 
governments in its implementation, and applies to all regulated 
sources, without distinction of the surrounding populations affected. 
Thus, Executive Order 13175 does not apply to this rule. EPA 
specifically solicits additional comment on this proposed rule from 
tribal officials.
---------------------------------------------------------------------------

    \320\ Executive Order 13084 is revoked by this Executive Order.
---------------------------------------------------------------------------

VII. Executive Order 13045: Protection of Children From Environmental 
Health and Safety Risks

    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.

VIII. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This rule is not subject to Executive Order 13211, ``Actions 
Concerning Regulations That Significantly Affect Energy Supply, 
Distribution, or Use'' (66 FR 28355 (May 22, 2001)). This rule, as 
proposed will not seriously disrupt energy supply, distribution 
patterns, prices, imports or exports. Furthermore, this rule is not an 
economically significant action under Executive Order 12866.

IX. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note) 
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.
    This proposed rulemaking involves environmental monitoring or 
measurement. Consistent with the Agency's Performance Based Measurement 
System (``PBMS''), EPA proposes not to require the use of specific, 
prescribed analytic methods. Rather, the Agency plans to allow the use 
of any method that meets the prescribed performance criteria. The PBMS 
approach is intended to be more flexible and cost-effective for the 
regulated community; it is also intended to encourage innovation in 
analytical technology and improved data quality. EPA is not precluding 
the use of any method, whether it constitutes a

[[Page 21362]]

voluntary consensus standard or not, as long as it meets the 
performance criteria specified.
    EPA welcomes comments on this aspect of the proposed rulemaking 
and, specifically, invites the public to identify potentially-
applicable voluntary consensus standards and to explain why such 
standards should be used in this regulation.

X. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898, ``Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations'' (February 
11, 1994) requires us to complete an analysis of today's rule with 
regard to equity considerations. The Order is designed to address the 
environmental and human health conditions of minority and low-income 
populations. This section briefly discusses potential impacts (direct 
or disproportional) today's rule may have in the area of environmental 
justice.
    To comply with the Executive Order, we have assessed whether 
today's rule may have negative or disproportionate effects on minority 
or low-income populations. We have recently analyzed demographic data 
from the U.S. Census. Previously we examined data from two other 
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 or 
disproportional health or safety 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.

XI. Congressional Review

    The Congressional Review Act (CRA), 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. Prior to publication of the final rule in 
the Federal Register, we will submit all necessary information to the 
U.S. Senate, the U.S. House of Representatives, and the Comptroller 
General of the United States. Under the CRA, a major rule cannot take 
effect until 60 days after it is published in the Federal Register. As 
proposed, this action is not a ``major rule'' as defined by 5 U.S.C. 
804(2).

List of Subjects

40 CFR Part 63

    Environmental protection, Air pollution control, Hazardous 
substances, Incorporation by reference, Reporting and recordkeeping 
requirements.

40 CFR Part 264

    Environmental protection, Air pollution control, Hazardous waste, 
Insurance, Packaging and containers, Reporting and recordkeeping 
requirements, Security measures, Surety bonds.

40 CFR Part 265

    Environmental protection, Air pollution control, Hazardous waste, 
Insurance, Packaging and containers, Reporting and recordkeeping 
requirements.

40 CFR Part 266

    Environmental protection, Energy, Hazardous waste, Recycling, 
Reporting and recordkeeping requirements.

40 CFR Part 270

    Environmental protection, Administrative practice and procedure, 
Confidential business information, Hazardous materials transportation, 
Hazardous waste, Reporting and recordkeeping requirements.

40 CFR Part 271

    Administrative practice and procedure, Hazardous materials 
transportation, Hazardous waste, Intergovernmental relations, Reporting 
and recordkeeping requirements.

    Dated: March 31, 2004.
Michael O. Leavitt,
Administrator.
    For the reasons set out in the preamble, title 40, chapter I, of 
the Code of Federal Regulations is proposed to be amended as follows:

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. Section 63.1200 is amended by revising the introductory text and 
paragraph (a)(2) to read as follows:


Sec.  63.1200  Who is subject to these regulations?

    The provisions of this subpart apply to all hazardous waste 
combustors: incinerators that burn hazardous waste, cement kilns that 
burn hazardous waste, lightweight aggregate kilns that burn hazardous 
waste, solid fuel-fired boilers that burn hazardous waste, liquid fuel-
fired boilers that burn hazardous waste, and hydrochloric acid 
production furnaces that burn hazardous waste. Hazardous waste 
combustors are also subject to applicable requirements under parts 260-
270 of this chapter.
    (a) * * *
    (2) Both area sources and major sources subject to this subpart, 
but 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.
* * * * *
    3. Section 63.1201 is amended in paragraph (a) by revising the 
definition of ``New source'', and adding definitions for ``Hydrochloric 
acid production furnace'', ``Liquid fuel-fired boiler'', and ``Solid 
fuel-fired boiler'' in alphabetical order to read as follows:


Sec.  63.1201  Definitions and acronyms used in this subpart.

    (a) * * *

[[Page 21363]]

    Hydrochloric acid production furnace and HCl production furnace 
mean a halogen acid furnace defined in Sec.  260.10 of this chapter 
that produces aqueous hydrochloric acid (HCl) product and that burns 
hazardous waste at any time.
* * * * *
    Liquid fuel-fired boiler and liquid boiler mean a boiler defined in 
Sec.  260.10 of this chapter that does not burn solid fuels and that 
burns hazardous waste at any time. Liquid fuel-fired boiler includes 
boilers that only burn gaseous fuels.
* * * * *
    New source means any affected source the construction or 
reconstruction of which is commenced after the dates specified under 
Sec. Sec.  63.1206(a)(1)(i)(B), (a)(1)(ii)(B), and (a)(2)(ii).
* * * * *
    Solid fuel-fired boiler and solid boiler mean a boiler defined in 
Sec.  260.10 of this chapter that burns a solid fuel and that burns 
hazardous waste at any time.
* * * * *
    4. Section 63.1206 is amended by:
    a. Revising paragraph (a).
    b. Revising paragraphs (b)(1)(ii), (b)(6) introductory text, 
(b)(7)(i)(A), (b)(9)(i) introductory text, (b)(10)(i) introductory 
text, (b)(11), (b)(13)(i) introductory text, and (b)(3)(ii).
    c. Revising paragraphs (c)(1)(i) introductory text and (c)(7)(ii) 
introductory text.
    d. Adding paragraphs (c)(7)(ii)(C) and (c)(7)(iii).
    The revisions and additions read as follows:


Sec.  63.1206  When and how must you comply with the standards and 
operating requirements?

    (a) Compliance dates. (1) Compliance dates for incinerators, cement 
kilns, and lightweight aggregate kilns that burn hazardous waste--(i) 
Compliance date for standards under Sec. Sec.  63.1203, 63.1204, and 
63.1205--(A) Compliance dates for existing sources. You must comply 
with the emission standards under Sec. Sec.  63.1203, 63.1204, and 
63.1205 and the other requirements of this subpart no later than the 
compliance date, September 30, 2003, unless the Administrator grants 
you an extension of time under Sec.  63.6(i) or Sec.  63.1213.
    (B) New or reconstructed sources. (1) If you commenced construction 
or reconstruction of your hazardous waste combustor after April 19, 
1996, you must comply with the emission standards under Sec. Sec.  
63.1203, 63.1204, and 63.1205 and the other requirements of this 
subpart by the later of September 30, 1999 or the date the source 
starts operations, except as provided by paragraph (a)(1)(i)(B)(2) of 
this section. The costs of retrofitting and replacement of equipment 
that is installed specifically to comply with this subpart, between 
April 19, 1996 and a source's compliance date, are not considered to be 
reconstruction costs.
    (2) For a standard under Sec. Sec.  63.1203, 63.1204, and 63.1205 
that is more stringent than the standard proposed on April 19, 1996, 
you may achieve compliance no later than September 30, 2003 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 the standards under Sec. Sec.  63.1203, 63.1204, and 
63.1205 at startup.
    (ii) Compliance date for standards under Sec. Sec.  63.1219, 
63.1220, and 63.1221--(A) Compliance dates for existing sources. You 
must comply with the emission standards under Sec. Sec.  63.1219, 
63.1220, and 63.1221 and the other requirements of this subpart no 
later than the compliance date, [date three years after date of 
publication of the final rule in the Federal Register], unless the 
Administrator grants you an extension of time under Sec.  63.6(i) or 
Sec.  63.1213.
    (B) New or reconstructed sources. (1) If you commenced construction 
or reconstruction of your hazardous waste combustor after April 20, 
2004, you must comply with the emission standards under Sec. Sec.  
63.1219, 63.1220, and 63.1221 and the other requirements of this 
subpart by the later of [date of publication of the final rule in the 
Federal Register] or the date the source starts operations, except as 
provided by paragraph (a)(1)(ii)(B)(2) of this section. The costs of 
retrofitting and replacement of equipment that is installed 
specifically to comply with this subpart, between April 20, 2004, and a 
source's compliance date, are not considered to be reconstruction 
costs.
    (2) For a standard under Sec. Sec.  63.1219, 63.1220, and 63.1221 
that is more stringent than the standard proposed on April 20, 2004, 
you may achieve compliance no later than [date three years after date 
of publication of the final rule in the Federal Register] if you comply 
with the standard proposed on April 20, 2004, after [date of 
publication of the final rule in the Federal Register]. This exception 
does not apply, however, to new or reconstructed area source hazardous 
waste combustors that become major sources after [date three years 
after date of publication of the final rule in the Federal Register]. 
As provided by Sec.  63.6(b)(7), such sources must comply with the 
standards under Sec. Sec.  63.1219, 63.1220, and 63.1221 at startup.
    (2) Compliance dates for solid fuel-fired boilers, liquid fuel-
fired boilers, and hydrogen chloride production furnaces that burn 
hazardous waste for standards under Sec. Sec.  63.1216, 63.1217, and 
63.1218.--(i) Compliance date for existing sources. You must comply 
with the standards of this subpart no later than the compliance date, 
[date three years after date of publication of the final rule in the 
Federal Register], unless the Administrator grants you an extension of 
time under Sec.  63.6(i) or Sec.  63.1213.
    (ii) New or reconstructed sources. (A) If you commenced 
construction or reconstruction of your hazardous waste combustor after 
April 20, 2004, you must comply with this subpart by the later of [date 
of publication of the final rule in the Federal Register] or the date 
the source starts operations, except as provided by paragraph 
(a)(2)(ii)(B) of this section. The costs of retrofitting and 
replacement of equipment that is installed specifically to comply with 
this subpart, between April 20, 2004, and a source's compliance date, 
are not considered to be reconstruction costs.
    (B) For a standard in the subpart that is more stringent than the 
standard proposed on April 20, 2004, you may achieve compliance no 
later than [date three years after date of publication of the final 
rule in the Federal Register] if you comply with the standard proposed 
on April 20, 2004, after [date of publication of the final rule in the 
Federal Register]. This exception does not apply, however, to new or 
reconstructed area source hazardous waste combustors that become major 
sources after [date three years after date of publication of the final 
rule in the Federal Register]. As provided by Sec.  63.6(b)(7), such 
sources must comply with this subpart at startup.
    (3) Early compliance. If you choose to comply with the emission 
standards of this subpart prior to the dates specified in paragraphs 
(a)(1) and (a)(2) of this section, your compliance date is the earlier 
of the date you postmark the Notification of Compliance under Sec.  
63.1207(j)(1) or the dates specified in paragraphs (a)(1) and (a)(2) of 
this section.
    (b) * * *
    (1) * * *
    (ii) When hazardous waste is not in the combustion chamber (i.e., 
the hazardous waste feed to the combustor has been cut off for a period 
of time not less than the hazardous waste residence

[[Page 21364]]

time) and you have documented in the operating record that you are 
complying with all otherwise applicable requirements and standards 
promulgated under authority of sections 112 (e.g., subparts LLL, NNNNN, 
DDDDD) or 129 of the Clean Air Act in lieu of the emission standards 
under Sec. Sec.  63.1203, 63.1204, 63.1205, 63.1215, 63.1216, 63.1217, 
63.1218, 63.1219, and 63.1220; the monitoring and compliance standards 
of this section and Sec. Sec.  63.1207 through 63.1209, except the 
modes of operation requirements of Sec.  63.1209(q); and the 
notification, reporting, and recordkeeping requirements of Sec. Sec.  
63.1210 through 63.1212.
* * * * *
    (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 of this subpart 
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.
* * * * *
    (7) * * * (i) * * *
    (A) You must document compliance with the Destruction and Removal 
Efficiency (DRE) standard under this subpart 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.
* * * * *
    (9) * * * (i) You may petition the Administrator to recommend 
alternative semivolatile metal, low volatile metal, mercury, or 
hydrogen chloride/chlorine gas emission standards under Sec.  63.1205 
if:
* * * * *
    (10) * * * (i) You may petition the Administrator to recommend 
alternative semivolatile metal, low volatile metal, mercury, or 
hydrogen chloride/chlorine gas emission standards under Sec.  63.1204 
if:
* * * * *
    (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 Sec. Sec.  63.1207(j) and 63.1210(d).
* * * * *
    (13) * * *
    (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 carbon monoxide and hydrocarbon 
standards of this subpart as follows:
* * * * *
    (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 this subpart as follows:
    (A) Existing sources must comply with the 20 parts per million by 
volume hydrocarbon standard of this subpart;
    (B) New sources must comply with the 20 parts per million by volume 
hydrocarbon standard of this subpart.
* * * * *
    (c) * * * (1) * * * (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 Sec. Sec.  
63.1207(j) and 63.1210(d), except:
* * * * *
    (7) * * *
    (ii) Bag leak detection system requirements. If your combustor is 
equipped with a baghouse (fabric filter), you must continuously operate 
a bag leak detection system that meets the specifications and 
requirements of paragraph (c)(7)(ii)(A) of this section and you must 
comply with the corrective measures requirements of paragraph 
(c)(7)(ii)(B) of this section.
* * * * *
    (C) Excessive exceedances notification. If you operate the 
combustor when the detector response exceeds the alarm set-point more 
than 5 percent of the time during any 6-month block time period, you 
must submit a notification to the Administrator within 5 days that 
describes the causes of the exceedances and the revisions to the 
design, operation, or maintenance of the combustor or baghouse you are 
taking to minimize exceedances.
    (iii) Particulate matter detection system requirements for 
electrostatic precipitators and ionizing wet scrubbers. If your 
combustor is equipped with an electrostatic precipitator or ionizing 
wet scrubber, and you elect not to establish under Sec.  
63.1209(m)(1)(iv) site-specific operating parameter limits that are 
linked to the automatic waste feed cutoff system under paragraph (c)(3) 
of this section, you must continuously operate a particulate matter 
detection system that meets the specifications and requirements of 
paragraph (c)(7)(iii)(A) of this section and you must comply with the 
corrective measures requirements of paragraph (c)(7)(iii)(B) of this 
section.
    (A) Particulate matter detection system requirements.--(1) The 
particulate matter detection system must be certified by the 
manufacturer to be capable of continuously detecting and recording 
particulate matter emissions at the loadings you expect to achieve 
during the comprehensive performance test;
    (2) The particulate matter detector shall provide output of 
relative or absolute particulate matter loadings;
    (3) The particulate matter detection system shall be equipped with 
an alarm system that will sound an audible alarm when an increase in 
relative or absolute particulate loadings is detected over the set-
point
    (4) You must install and operate the particulate matter detection 
system 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) You must establish the alarm set-point as the average detector 
response of the test run averages achieved during the comprehensive 
performance test demonstrating compliance with the particulate matter 
emission standard. You must comply with the alarm set-point on a 6-hour 
rolling average, updated each hour with a one-hour block average that 
is the average of the detector responses over each 15-minute block.
    (6) Where multiple detectors are required to monitor multiple 
control devices, the system's instrumentation and alarm system may be 
shared among the detectors.
    (B) Particulate matter detection system corrective measures 
requirements. The operating and maintenance plan required by paragraph 
(c)(7)(i) of this section must include a corrective measures plan that 
specifies the procedures you will follow in the case of a particulate 
matter 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

[[Page 21365]]

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 shutting down the 
combustor.
    (C) Excessive exceedances notification. If you operate the 
combustor when the detector response exceeds the alarm set-point more 
than 5 percent of the time during any 6-month block time period, you 
must submit a notification to the Administrator within 5 days that 
describes the causes of the exceedances and the revisions to the 
design, operation, or maintenance of the combustor or electrostatic 
precipitator or ionizing wet scrubber you are taking to minimize 
exceedances.
    5. Section 63.1207 is amended by:
    a. Revising paragraph (b)(1).
    b. Adding paragraph (b)(3).
    c. Revising paragraph (c)(1).
    d. Adding paragraph (c)(3).
    e. Revising paragraphs (e)(2) and (e)(3)(iv).
    f. Revising paragraphs (f)(1)(ii)(D ), (f)(1)(xiii), and 
(f)(1)(xiv).
    g. Adding paragraph (f)(1)(xv).
    h. Revising paragraphs (j)(1)(ii) and (j)(3).
    i. Revising paragraph (l)(1) introductory text.
    The revisions and additions read as follows:


Sec.  63.1207  What are the performance testing requirements?

* * * * *
    (b) * * *
    (1) Comprehensive performance test. You must conduct comprehensive 
performance tests to demonstrate compliance with the emission standards 
provided by the subpart, establish limits for the operating parameters 
provided by Sec.  63.1209, and demonstrate compliance with the 
performance specifications for continuous monitoring systems.
* * * * *
    (3) One-Time Dioxin/Furan Test for Boilers Not Subject to a 
Numerical Dioxin/Furan Standard. For boilers that are not subject to a 
numerical dioxin/furan emission standard under Sec. Sec.  63.1216 and 
63.1217--solid fuel-fired boilers, and those liquid fuel-fired boilers 
that are not equipped with a dry particulate matter control device--you 
must conduct a one-time emission test for dioxin/furan under feed and 
operating conditions that are most likely to maximize dioxin/furan 
emissions, similar to a dioxin/furan compliance test.
    (i) You must conduct the dioxin/furan emissions test no later than 
the deadline for conducting the initial comprehensive performance test.
    (ii) You may use dioxin/furan emissions data from previous testing 
to meet this requirement, provided that:
    (A) The testing was conducted under feed and operating conditions 
that are most likely to maximize dioxin/furan emissions, similar to a 
dioxin/furan compliance test;
    (B) You have not changed the design or operation of the boiler in a 
manner that could significantly affect stack gas dioxin/furan emission 
concentrations; and
    (C) The data meet quality assurance objectives that may be 
determined on a site-specific basis.
    (iii) You may use dioxin/furan emissions data from a boiler to 
represent emissions from another on-site boiler in lieu of testing 
(i.e., data in lieu of testing) if the design and operation, including 
fuels and hazardous waste feed, of the boilers are identical.
    (iv) You must include the results of the one-time dioxin/furan 
emissions test with the results of the initial comprehensive 
performance test in the Notification of Compliance.
    (v) You must repeat the dioxin/furan emissions test if you change 
the design or operation of the source in a manner that may increase 
dioxin/furan emissions.
    (c) * * * (1) Test date. Except as provided by paragraphs (c)(2) 
and (c)(3) of this section, you must commence the initial comprehensive 
performance test not later than six months after the compliance date.
* * * * *
    (3) For incinerators, cement kilns, and lightweight aggregate 
kilns, you must commence the initial comprehensive performance test to 
demonstrate compliance with the standards under Sec. Sec.  63.1219, 
63.1220, and 63.1221 not later than 12 months after the compliance 
date.
* * * * *
    (e) * * *
    (2) After the Administrator has approved the site-specific test 
plan and CMS performance evaluation test plan, but no later than 60 
calendar days before initiation of the test, you must make the test 
plans available to the public for review. You must issue a public 
notice to all persons on your facility/public mailing list (developed 
pursuant to 40 CFR 70.7(h), 71.11(d)(3)(i)(E) and 124.10(c)(1)(ix)) 
announcing the approval of the test plans and the location where the 
test plans are available for review. The test plans must be accessible 
to the public for 60 calendar days, beginning on the date that you 
issue your public notice. The location must be unrestricted and provide 
access to the public during reasonable hours and provide a means for 
the public to obtain copies. The notification must include the 
following information at a minimum:
    (i) The name and telephone number of the source's contact person;
    (ii) The name and telephone number of the regulatory agency's 
contact person;
    (iii) The location where the approved test plans and any necessary 
supporting documentation can be reviewed and copied;
    (iv) The time period for which the test plans will be available for 
public review; and
    (v) An expected time period for commencement and completion of the 
performance test and CMS performance evaluation test.
    (3) * * *
    (iv) Public notice. At the same time that you submit your petition 
to the Administrator, you must notify the public (e.g., distribute a 
notice to the facility/public mailing list developed pursuant to 40 CFR 
70.7(h), 71.11(d)(3)(i)(E) and 124.10(c)(1)(ix)) of your petition to 
waive a performance test. The notification must include all of the 
following information at a minimum:
    (A) The name and telephone number of the source's contact person;
    (B) The name and telephone number of the regulatory agency's 
contact person;
    (C) The date the source submitted its site-specific performance 
test plan and CMS performance evaluation test plans; and
    (D) The length of time requested for the waiver.
    (f) * * *
    (1) * * *
    (ii) * * *
    (D) The Administrator may approve on a case-by-case basis a 
hazardous waste feedstream analysis for organic hazardous air 
pollutants in lieu of the analysis required under paragraph 
(f)(1)(ii)(A) of this section if the reduced analysis is sufficient to 
ensure that the POHCs used to demonstrate compliance with the 
applicable DRE standards of this subpart continue to be representative 
of the organic hazardous air pollutants in your hazardous waste 
feedstreams;
* * * * *

[[Page 21366]]

    (xiii) For cement kilns with in-line raw mills, if you elect to use 
the emissions averaging provision of this subpart, you must notify the 
Administrator of your intent in the initial (and subsequent) 
comprehensive performance test plan, and provide the information 
required by the emission averaging provision;
    (xiv) For preheater or preheater/precalciner cement kilns with dual 
stacks, if you elect to use the emissions averaging provision of this 
subpart, you must notify the Administrator of your intent in the 
initial (and subsequent) comprehensive performance test plan, and 
provide the information required by the emission averaging provision;
    (xv) If you request to use Method 23 for dioxin/furan you must 
provide the information required under Sec.  63.1208(b)(1)(i)(B);
* * * * *
    (j) * * * (1) * * *
    (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).
* * * * *
    (3) See Sec. Sec.  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).
* * * * *
    (l) Failure of performance test--(1) Comprehensive performance 
test. The provisions of this paragraph do not apply to the initial 
comprehensive performance test if you conduct the test prior to your 
compliance date.
* * * * *
    6. Section 63.1208 is amended by revising paragraphs (b)(1)(i) and 
(b)(5) to read as follows:


Sec.  63.1208  What are the test methods?

* * * * *
    (b) * * *
    (1) * * * (i) To determine compliance with the emission standard 
for dioxins and furans, you must use:
    (A) Method 0023A, Sampling Method for Polychlorinated Dibenzp-p-
Dioxins and Polychlorinated Dibenzofurans emissions from Stationary 
Sources, EPA Publication SW-846, as incorporated by reference in 
paragraph (a) of this section; or
    (B) Method 23, provided in appendix A, part 60 of this chapter, 
except that for coal-fired boilers, sources equipped with an activated 
carbon injection system, and other sources that the Administrator 
determines may emit carbonaceous particulate matter that may bias 
Method 23 results, you may use Method 23 only upon the Administrator's 
approval. In determining whether to grant approval to use Method 23, 
the Administrator may consider factors including whether dioxin/furan 
are detected at levels substantially below the emission standard, and 
whether previous Method 0023 analyses detected low levels of dioxin/
furan in the front half.
* * * * *
    (5) Hydrogen chloride and chlorine gas--(i) Compliance with MACT 
standards. To determine compliance with the emission standard for 
hydrogen chloride and chlorine gas (combined), you must use:
    (A) Method 26/26A as provided in appendix A, part 60 of this 
chapter; or
    (B) Methods 320 or 321 as provided in appendix A, part 60 of this 
chapter, or ASTM D 6735-01, Test Method for Measurement of Gaseous 
Chlorides and Fluorides from Mineral Calcining Exhaust Sources--
Impinger Method to measure emissions of hydrogen chloride, and Method 
26/26A to measure emissions of chlorine gas.
    (ii) Compliance with risk-based limits under Sec.  63.1215. To 
demonstrate compliance with emission limits established under Sec.  
63.1215, you must use Methods 26/26A, 320,or 321, or ASTM D 6735-01, 
Test Method for Measurement of Gaseous Chlorides and Fluorides from 
Mineral Calcining Exhaust Sources--Impinger Method, except:
    (A) For cement kilns and sources equipped with a dry acid gas 
scrubber, you must use Methods 320 or 321, or ASTM D 6735-01 to measure 
hydrogen chloride, and the back-half, caustic impingers of Method 26/
26A to measure chlorine gas; and
    (B) For incinerators, boilers, and lightweight aggregate kilns, you 
must use Methods 320 or 321, or ASTM D 6735-01 to measure hydrogen 
chloride, and Method 26/26A to measure total chlorine, and calculate 
chlorine gas by difference if:
    (1) The bromine/chlorine ratio in feedstreams is greater than 5 
percent; or
    (2) The sulfur/chlorine ratio in feedstreams is greater than 50 
percent.
* * * * *
    7. Section 63.1209 is amended by:
    a. Revising paragraphs (a)(1)(ii)(A), (a)(1)(iv)(D), and 
(a)(1)(v)(D).
    b. Revising paragraph (f)(1).
    c. Revising the heading of paragraph (g)(1) introductory text and 
paragraph (g)(1)(i).
    d. Revising paragraphs (k)(1)(i) and (k)(2)(i).
    e. Revising paragraph (l)(1).
    f. Revising paragraph (m)(1)(iv) introductory text.
    g. Revising paragraph (n)(2).
    h. Revising paragraph (o)(1).
    i. Revising paragraph (q)(1)(ii).
    The revisions read as follows:


Sec.  63.1209  What are the monitoring requirements?

    (a) * * * (1) * * *
    (ii) * * *
    (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
* * * * *
    (iv) * * *
    (D) To remain in compliance, all six-minute block averages must not 
exceed the opacity standard.
    (v) * * *
    (D) To remain in compliance, all six-minute block averages must not 
exceed the opacity standard.
* * * * *
    (f) * * *
    (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 Sec.  63.8(c)(3).
* * * * *
    (g) * * *
    (1) Requests to use alternatives to operating parameter monitoring 
requirements. (i) You may submit an application to the Administrator or 
State with an approved Title V program under this paragraph for 
approval of alternative operating parameter 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).
* * * * *
    (k) * * *
    (1) * * * (i) For sources other than a lightweight aggregate kiln, 
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.
* * * * *
    (2) * * * (i) For sources other than cement kilns, you must measure 
the

[[Page 21367]]

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. Sec.  63.1207(e) and (f);
* * * * *
    (l) * * *
    (1) Feedrate of mercury. (i) For incinerators, cement kilns, and 
lightweight aggregate kilns, when complying with the mercury emission 
standards under Sec. Sec.  63.1203, 63.1204, and 63.1205, and for solid 
fuel-fired boilers, you must establish a 12-hour rolling average limit 
for the total feedrate of mercury in all feedstreams as the average of 
the test run averages.
    (ii) For incinerators, cement kilns, and lightweight aggregate 
kilns, when complying with the mercury emission standards under 
Sec. Sec.  63.1219, 63.1220, and 63.1221, you must establish an annual 
rolling average limit for the total feedrate of mercury in all 
feedstreams as follows:
    (A) You must calculate a mercury system removal efficiency for each 
test run as [1--mercury emission rate (g/s) / mercury feedrate (g/s)], 
and calculate the average system removal efficiency of the test run 
averages, except if your source is not equipped with a control system 
that consistently and reproducibly controls mercury emissions, you must 
assume zero system removal efficiency. If emissions exceed the mercury 
emission standard, it is not a violation because compliance with these 
mercury emission standards, which are derived from normal emissions 
data, is based on compliance with the mercury feedrate limit on an 
annual rolling average.
    (B) You must calculate the annual average mercury feedrate limit as 
the mercury emission standard ([mu]g/m \3\) divided by the system 
removal efficiency. The feedrate limit is expressed as an emission 
concentration, [mu]g mercury/m \3\ of stack gas.
    (C) You must comply with the emission concentration-based annual 
average mercury feedrate limit by measuring the mercury feedrate (g/s) 
and the stack gas flowrate (m \3\/s) at least once a minute to 
calculate a 60-minute average emission concentration-based feedrate as 
[mercury feedrate (g/s) / gas flowrate (m \3\/s)].
    (D) You must calculate an annual rolling average mercury feedrate 
that is updated each hour.
    (iii) For liquid fuel-fired boilers, you must establish an annual 
rolling average hazardous waste mercury thermal concentration limit, as 
follows:
    (A) You must calculate a mercury system removal efficiency for each 
test run as [1--mercury emission rate (g/s) / mercury feedrate (g/s)], 
and calculate the average system removal efficiency of the test run 
averages, except if your source is not equipped with a control system 
that consistently and reproducibly controls mercury emissions, you must 
assume zero system removal efficiency. If emissions exceed the mercury 
emission standard, it is not a violation because compliance with the 
mercury emission standard, which is derived from normal emissions data, 
is based on compliance with the hazardous waste mercury thermal 
concentration limit on an annual rolling average.
    (B) You must calculate the annual average hazardous waste mercury 
thermal concentration limit as the mercury emission standard (lb/MM 
Btu) divided by the system removal efficiency. The hazardous waste 
thermal concentration limit is expressed as: lb mercury in hazardous 
waste feedstreams per million Btu of hazardous waste.
    (C) You must comply with the annual average hazardous waste mercury 
thermal concentration limit by measuring the feedrate of mercury in all 
hazardous waste feedstreams (lb/s) and the hazardous waste thermal 
feedrate (MM Btu/s) at least once a minute to calculate a 60-minute 
average thermal emission concentration as [hazardous waste mercury 
feedrate (g/s) / hazardous waste thermal feedrate (MM Btu/s)].
    (D) You must calculate an annual rolling average hazardous waste 
mercury thermal concentration that is updated each hour.
    (iv) Extrapolation of feedrate levels. (A) In lieu of establishing 
mercury feedrate limits as specified in paragraphs (l)(1)(i) through 
(iii) of this section, you may request as part of the performance test 
plan under Sec. Sec.  63.6(b) and (c) and Sec. Sec.  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. 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.
    (B) The Administrator will review the performance test results in 
making a finding of compliance required by Sec. Sec.  63.6(f)(3) and 
63.1206(b)(3) to ensure that you have interpreted the performance test 
results properly and the extrapolation procedure is appropriate for 
your source.
* * * * *
    (m) * * *
    (1) * * *
    (iv) Other particulate matter control devices. For each particulate 
matter control device that is not a fabric filter or high energy wet 
scrubber, or is not an electrostatic precipitator or ionizing wet 
scrubber for which you elect to monitor particulate matter loadings 
under Sec.  63.1206(c)(7)(iii) of this chapter for process control, 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:
* * * * *
    (n) * * *
    (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)(vii) of 
this section.
    (ii) For incinerators, cement kilns, and lightweight aggregate 
kilns, when complying with the emission standards under Sec. Sec.  
63.1203, 63.1204, 63.1205, and 63.1219 and for solid fuel-fired 
boilers, you must establish 12-hour rolling average limits for the 
total feedrate of semivolatile and low volatile metals in all 
feedstreams as the average of the test run averages and as specified in 
paragraph (n)(2)(iv) of this section.
    (iii) For cement kilns, when complying with the emission standards 
under Sec.  63.1220, you must establish 12-hour rolling average 
feedrate limits for semivolatile and low volatile metals as the thermal 
concentration of semivolatile metals or low volatile metals in all 
hazardous waste feedstreams. You must calculate hazardous waste thermal 
concentrations for semivolatile metals and low volatile metals for each 
run as the total mass feedrate of semivolatile metals or low volatile 
metals for all hazardous waste feedstreams divided by the total heat 
input rate for all hazardous waste feedstreams. The 12-hour rolling 
average feedrate limits for semivolatile metals and low volatile metals 
are the

[[Page 21368]]

average of the hazardous waste thermal concentrations for the runs.
    (iv) Lightweight aggregate kilns under Sec.  63.1221--(A) Existing 
sources. When complying with the emission standards under Sec.  
63.1221, you must establish semivolatile metal and low volatile metal 
feedrate limits as 12-hour rolling average feedrate limits and 12-hour 
rolling average hazardous waste thermal concentrations as specified in 
paragraphs (n)(2)(ii) and (iii). You must comply with both feedrate 
limits for semivolatile metals and low volatile metals.
    (B) New sources. When complying with the emission standards under 
Sec.  63.1221, you must establish semivolatile metal and low volatile 
metal feedrate limits as 12-hour rolling average hazardous waste 
thermal concentrations as specified in paragraphs (n)(2)(ii) and (iii).
    (v) Liquid fuel-fired boilers. (A) For semivolatile metals, you 
must establish an annual rolling average hazardous waste thermal 
concentration limit, as follows:
    (1) You must calculate a semivolatile metals system removal 
efficiency for each test run as [1--semivolatile metals emission rate 
(g/s) / semivolatile metals feedrate (g/s)], and calculate the average 
system removal efficiency of the test run averages, except if your 
source is not equipped with a control system that consistently and 
reproducibly controls semivolatile metals emissions, you must assume 
zero system removal efficiency. If emissions exceed the semivolatile 
metals emission standard, it is not a violation because compliance with 
the semivolatile metals emission standard, which is derived from normal 
emissions data, is based on compliance with the semivolatile metals 
hazardous waste thermal concentration limit on an annual rolling 
average.
    (2) You must calculate the annual average hazardous waste 
semivolatile metals thermal concentration limit as the semivolatile 
metals emission standard (lb/MM Btu) divided by the system removal 
efficiency. The hazardous waste thermal concentration limit is 
expressed as: pounds semivolatile metals in hazardous waste feedstreams 
per million Btu of hazardous waste.
    (3) You must comply with the annual average hazardous waste 
semivolatile metals thermal concentration limit by measuring the 
feedrate of semivolatile metals in all hazardous waste feedstreams (lb/
s) and the hazardous waste thermal feedrate (MM Btu/s) at least once a 
minute to calculate a 60-minute average thermal emission concentration 
as [hazardous waste semivolatile metals feedrate (g/s) / hazardous 
waste thermal feedrate (MM Btu/s)].
    (4) You must calculate an annual rolling average hazardous waste 
semivolatile metals thermal concentration that is updated each hour.
    (B) For low volatile metals, you must establish 12-hour rolling 
average feedrate limits for chromium as the thermal concentration of 
chromium in all hazardous waste feedstreams. You must calculate a 
hazardous waste thermal concentration for chromium for each run as the 
total mass feedrate of chromium for all hazardous waste feedstreams 
divided by the total heat input rate for all hazardous waste 
feedstreams. The 12-hour rolling average feedrate limit for chromium is 
the average of the hazardous waste thermal concentrations for the runs.
    (vi) LVM limits for pumpable wastes. You must establish separate 
feedrate limits for low volatile metals in pumpable feedstreams using 
the procedures prescribed above for total low volatile metals. 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.
    (vii) Extrapolation of feedrate levels. In lieu of establishing 
feedrate limits as specified in paragraphs (l)(1)(i) through (iii) of 
this section, you may request as part of the performance test plan 
under Sec. Sec.  63.6(b) and (c) and 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. 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);
    (B) Whether the extrapolated feedrates you request are warranted 
considering historical metal feedrate data; and
    (C) Whether you have interpreted the performance test results 
properly and the extrapolation procedure is appropriate for your 
source.
* * * * *
    (o) * * *
    (1) Feedrate of total chlorine and chloride--(i) Incinerators, 
cement kilns, lightweight aggregate kilns, solid fuel-fired boilers, 
and hydrochloric acid production furnaces. You must establish 12-hour 
rolling average limit for the total feedrate of chlorine (organic and 
inorganic) in all feedstreams as the average of the test run averages.
    (ii) Liquid fuel-fired boilers. You must establish a 12-hour 
rolling average limit for the feedrate of chlorine (organic and 
inorganic) as the thermal concentration of chlorine in all hazardous 
waste feedstreams. You must calculate a hazardous waste thermal 
concentration for chlorine for each run as the total mass feedrate of 
chlorine for all hazardous waste feedstreams divided by the total heat 
input rate for all hazardous waste feedstreams. The 12-hour rolling 
average feedrate limit chlorine is the average of the hazardous waste 
thermal concentrations for the runs.
* * * * *
    (q) * * *
    (1) * * *
    (ii) You must specify (e.g., by reference) the otherwise applicable 
requirements as a mode of operation in your Documentation of Compliance 
under Sec.  63.1211(d), your Notification of Compliance under Sec.  
63.1207(j), and your title V permit application. These requirements 
include the otherwise applicable requirements governing emission 
standards, monitoring and compliance, and notification, reporting, and 
recordkeeping.
* * * * *
    8. Section 63.1210 is amended by:
    a. Revising the table in paragraph (a)(1) and the table in 
paragraph (a)(2).
    b. Redesignating paragraph (b) as (d).
    c. Adding new paragraph (b).
    d. Adding new paragraph (c).
    The revisions and additions read as follows:


Sec.  63.1210  What are the notification requirements?

    (a) * * *
    (1) * * *

------------------------------------------------------------------------
             Reference                          Notification
------------------------------------------------------------------------
63.9(b)...........................  Initial notifications that you are
                                     subject to subpart EEE of this
                                     part.
63.9(d)...........................  Notification that you are subject to
                                     special compliance requirements.

[[Page 21369]]

 
63.9(j)...........................  Notification and documentation of
                                     any change in information already
                                     provided under Sec.   63.9.
63.1206(b)(5)(i)..................  Notification of changes in design,
                                     operation, or maintenance.
63.1206(c)(7)(ii)(C)..............  Notification of excessive bag leak
                                     detection system exceedances.
63.1207(e), 63.9(e), 63.9(g)(1)     Notification of performance test and
 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,
 63.1207(k), 63.1207(l), 63.9(h),    including results of performance
 63.10(d)(2), 63.10(e)(2).           tests and continuous monitoring
                                     system performance evaluations.
------------------------------------------------------------------------
\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) * * *

------------------------------------------------------------------------
                                     Notification, request, petition, or
             Reference                           application
------------------------------------------------------------------------
63.9(i)...........................  You may request an adjustment to
                                     time periods or postmark deadlines
                                     for submittal and review of
                                     required information.
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.
63.1204(d)(2)(iii),                 Notification that you elect to
 63.1220(d)(2)(iii).                 comply with the emission averaging
                                     requirements for cement kilns with
                                     in-line raw mills.
63.1204(e)(2)(iii),                 Notification that you elect to
 63.1220(e)(2)(iii).                 comply with the emission averaging
                                     requirements for preheater or
                                     preheater/precalciner kilns with
                                     dual stacks.
63.1206(b)(4), 63.1213, 63.6(i),    You may request an extension of the
 63.9(c).                            compliance date for up to one year.
63.1206(b)(5)(i)(C)...............  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)(8)(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)(8)(v)..................  You may request approval to have the
                                     particulate matter and opacity
                                     standards and associated operating
                                     limits and conditions waived for
                                     more than 96 hours for a
                                     correlation test.
63.1206(b)(9).....................  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)(10)....................  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 elect to comply with an
                                     alternative to the particulate
                                     matter standard.
63.1206(b)(15)....................  Owners and operators of cement and
                                     lightweight aggregate kilns may
                                     request to comply with the
                                     alternative to the interim
                                     standards for mercury.
63.1206(c)(2)(ii)(C)..............  You may request to make changes to
                                     the startup, shutdown, and
                                     malfunction plan.
63.1206(c)(5)(i)(C)...............  You may request an alternative means
                                     of control to provide control of
                                     combustion system leaks.
63.1206(c)(5)(i)(D)...............  You may request other techniques to
                                     prevent fugitive emissions without
                                     use of instantaneous pressure
                                     limits.
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(e)(3), 63.7(h)............  You may request a time extension if
                                     the Administrator fails to approve
                                     or deny your test plan.
63.1207(h)(2).....................  You may request to waive current
                                     operating parameter limits during
                                     pretesting for more than 720 hours.
63.1207(f)(1)(ii)(D)..............  You may request a reduced hazardous
                                     waste feedstream analysis for
                                     organic hazardous air pollutants if
                                     the reduced analysis continues to
                                     be representative of organic
                                     hazardous air pollutants in your
                                     hazardous waste feedstreams.
63.1207(g)(2)(v)..................  You may request to operate under a
                                     wider operating range for a
                                     parameter during confirmatory
                                     performance testing.
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(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.
63.1209(g)(1).....................  You may request approval of: (1)
                                     Alternatives to operating parameter
                                     monitoring requirements, 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(l)(1).....................  You may request to extrapolate
                                     mercury feedrate limits.
63.1209(n)(2).....................  You may request to extrapolate
                                     semivolatile and low volatile metal
                                     feedrate limits.
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.
------------------------------------------------------------------------


[[Page 21370]]

    (b) Notification of intent to comply (NIC). (1) You must prepare a 
Notification of Intent to Comply that includes all of 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 general description of how you intend to comply with the 
emission standards of this subpart.
    (ii) As applicable to each source, information on key activities 
and estimated dates for these activities that will bring the source 
into compliance with emission control requirements of this subpart. You 
must include all of the following key activities and dates in your NIC:
    (A) The dates by which you will develop engineering designs for 
emission control systems or process changes for emissions;
    (B) The date by which you will commit internal or external 
resources for installing emission control systems or making 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 your how you intend 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 intend to cease burning hazardous waste prior to or on 
the compliance date, you must include in your NIC a schedule of key 
dates for the steps to be taken to stop hazardous waste activity at 
your combustion unit. Key dates include the date for submittal of RCRA 
closure documents required under subpart G, part 264 of this chapter.
    (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 one year following the effective date of the emission standards of 
this subpart.
    (c) NIC public meeting and notice. (1) Prior to the submission of 
the NIC to the permitting agency, and no later than 10 months after the 
effective date of the emission standards of this subpart, 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 all of 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 (and final NIC, if 
requested) can be obtained; and
    (vi) The name, address, and telephone number of a contact person 
for the NIC.
    9. Section 63.1211 is amended by:
    a. Revising the table in paragraph (b).
    b. Redesignating paragraphs (c) and (d) as (d) and (e).
    c. Adding new paragraph (c).
    The revisions and additions read as follows:


Sec.  63.1211  What are the recordkeeping and reporting requirements?

* * * * *
    (b) * * *

------------------------------------------------------------------------
             Reference                 Document, data, or information
------------------------------------------------------------------------
63.1200, 53.10 (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.
63.1204(d)(1)(ii),                  Documentation of mode of operation
 63.1220(d)(1)(ii).                  changes for cement kilns with in-
                                     line raw mills.
63.1204(d)(2)(ii),                  Documentation of compliance with the
 63.1220(d)(2)(ii).                  emission averaging requirements for
                                     cement kilns with in-line raw
                                     mills.
63.1204(e)(2)(ii),                  Documentation of compliance with the
 63.1220(e)(2)(ii).                  emission averaging requirements for
                                     preheater or preheater/precalciner
                                     kilns with dual stacks.

[[Page 21371]]

 
63.1206(b)(1)(ii).................  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(b)(5)(ii).................  Documentation that a change will not
                                     adversely affect compliance with
                                     the emission standards or operating
                                     requirements.
63.1206(b)(11)....................  Calculation of hazardous waste
                                     residence time.
63.1206(c)(2).....................  Startup, shutdown, and malfunction
                                     plan.
63.1206(c)(2)(v)(A)...............  Documentation of your investigation
                                     and evaluation of excessive
                                     exceedances during malfunctions.
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)(3)(vii)................  Documentation and results of the
                                     automatic waste feed cutoff
                                     operability testing.
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)(5)(ii).................  Method used for control of
                                     combustion system leaks.
63.1206(c)(6).....................  Operator training and certification
                                     program.
63.1206(c)(7)(i)(D)...............  Operation and maintenance plan.
63.1209(c)(2).....................  Feedstream analysis plan.
63.1209(k)(6)(iii),                 Documentation that a substitute
 63.1209(k)(7)(ii),                  activated carbon, dioxin/furan
 63.1209(k)(9)(ii),                  formation reaction inhibitor, or
 63.1209(o)(4)(iii).                 dry scrubber sorbent will provide
                                     the same level of control as the
                                     original material.
63.1209(k)(7)(i)(C)...............  Results of carbon bed performance
                                     monitoring.
63.1209(q)........................  Documentation of changes in modes of
                                     operation.
63.1211(d)........................  Documentation of compliance.
------------------------------------------------------------------------

    (c) Compliance progress reports associated with the notification of 
intent to comply--(1) General. Not later than two years following the 
effective date of the emission standards of this subpart, you must 
comply with the following, unless you comply with paragraph (c)(2)(ii) 
of this section:
    (i) Develop 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) Document an internal or external commitment of resources, 
i.e., funds or personnel, to purchase, fabricate, and install any 
equipment, devices, and ancillary structures needed to comply with the 
emission standards and operating requirements of this subpart.
    (2) Progress report. (i) You must submit to the Administrator a 
progress report not later than two years following the effective date 
of the emission standards of this subpart, which contains information 
documenting that you have met the requirements of paragraph (c)(1) of 
this section and updates the information you previously provided in 
your NIC. 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. In any evaluation of adequate 
progress, the Administrator may consider any delays in a source's 
progress caused by the time required to obtain necessary permits (e.g., 
operating and construction permits or licenses) from governmental 
regulatory agencies when the sources have submitted timely and complete 
permit applications.
    (ii) If you can comply with the emission standards and operating 
requirements of this subpart, without undertaking any of the activities 
described in paragraph (c)(1) of this section, you must submit a 
progress report documenting either:
    (A) That you, at the time of the progress report, are in compliance 
with the emission standards and operating requirements; or
    (B) The steps you will take to comply, without undertaking any of 
the activities listed in paragraphs (c)(1)(i) through (c)(1)(iii) of 
this section.
    (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 for the time period between submission of 
the progress report and the compliance date of the emission standards 
and operating requirements of this subpart.
    (ii) The schedule must contain anticipated or actual dates for all 
of the following:
    (A) Bid and award dates, as necessary, 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 will be submitted for operating 
and construction permits or licenses;
    (D) The dates by which approvals of any operating and construction 
permits or licenses are anticipated; and
    (E) The projected date by which you expect to comply with the 
emission standards and operating requirements of this subpart.
    (4) Sources that intend to cease burning hazardous waste prior to 
or on the compliance date. (i) If you indicated in your NIC your intent 
to cease burning hazardous waste and do so prior to submitting a 
progress report, you are exempt from the requirements of paragraphs 
(c)(1) through (c)(3) of this section. However, you must submit and 
include in your progress report the date on which you stopped burning 
hazardous waste and the date(s) you submitted, or plan to submit RCRA 
closure documents.
    (ii) If you signify in the progress report, submitted not later 
than two years following the effective date of the emission standards 
of this subpart, your intention to cease burning hazardous waste, you 
must stop burning hazardous waste on or before the compliance date of 
the emission standards of this subpart.
* * * * *
    10. Section 63.1212 is added to subpart EEE to read as follows:


Sec.  63.1212  What are the other requirements pertaining to the NIC 
and associated progress report?

    (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

[[Page 21372]]

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 the effective 
date of the emission standards of this subpart. (1) If you begin to 
burn hazardous waste after the effective date of the emission standards 
of this subpart, but prior to nine months after the effective date of 
the emission standards of this subpart, you must comply with the 
requirements of Sec. Sec.  63.1206(a)(2), 63.1210(b) and (c), 
63.1211(c), 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 more than nine 
months after the effective date of the emission standards of this 
subpart, you must comply with the requirements of Sec. Sec.  
63.1206(a)(2), 63.1210(b) and (c), 63.1211(c), 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.
    11. Section 63.1214 is amended by revising paragraphs (c)(1), 
(c)(2), (c)(3), and (c)(4) to read as follows:


Sec.  63.1214  Implementation and enforcement.

* * * * *
    (c) * * *
    (1) Approval of alternatives to requirements in Sec. Sec.  63.1200, 
63.1203, 63.1204, 63.1205, 63.1206(a), 63.1215, 63.1216, 63.1217, 
63.1218, 63.1219, 63.1220, and 63.1221.
    (2) Approval of major alternatives to test methods under Sec. Sec.  
63.7(e)(2)(ii) and (f), 63.1208(b), and 63.1209(a)(1), as defined in 
Sec.  63.90, and as required in this subpart.
    (3) Approval of major alternatives to monitoring under Sec. Sec.  
63.8(f) and 63.1209(a)(5), as defined in Sec.  63.90, and as required 
in this subpart.
    (4) Approval of major alternatives to recordkeeping and reporting 
under Sec. Sec.  63.10(f) and 63.1211(a) through (d), as defined in 
Sec.  63.90, and as required in this subpart.
    12. Section Sec.  63.1215 is added to subpart EEE to read as 
follows:


Sec.  63.1215  What are the alternative risk-based standards for total 
chlorine?

    (a) General. You may establish and comply with site-specific, risk-
based emission limits for total chlorine under the procedures 
prescribed in this section. You may comply with these risk-based 
emission limits in lieu of the emission standards for total chlorine 
provided under Sec. Sec.  63.1216, 63.1217, 63.1219, 63.1220, and 
63.1221 of this chapter after review and approval by the permitting 
authority. To identify and comply with the limits, you must:
    (1) Identify hydrogen chloride and chlorine gas emission rates for 
each on-site hazardous waste combustor. You may select hydrogen 
chloride and chlorine gas emission rates as you choose to demonstrate 
eligibility for the total chlorine standards under this section, except 
as provided by paragraph (b)(4) of this section;
    (2) Perform an eligibility demonstration to determine if your HCl-
equivalent emission rate limits meet the national exposure standards, 
as prescribed by paragraphs (b) and (c) of this section;
    (3) Submit your eligibility demonstration for review and approval, 
as prescribed by paragraph (d) of this section;
    (4) Demonstrate compliance with the HCl-equivalent emission rate 
limits, as prescribed by the testing and monitoring requirements under 
paragraph (e) of this section; and
    (5) Comply with the requirements for changes, as prescribed by 
paragraph (f) of this section.
    (b) HCl-equivalent emission rates. (1) You must establish a total 
chlorine limit for each hazardous waste combustor as an HCl-equivalent 
emission rate.
    (2) You must calculate the toxicity-weighted HCl-equivalent 
emission rate for each combustor as follows:

    ERtw = [sum](ERi x (RfCHCl/
RfCi))

Where:

ERtw is the HCl-equivalent emission rate, lb/hr
ERi is the emission rate of HAP i in lbs/hr
RfCi is the reference concentration of HAP i
RfCHCl is the reference concentration of HCl

    (3) You must use the RfC values for hydrogen chloride and chlorine 
gas found at http://epa.gov/ttn/atw/toxsource/sumnmary.html.
    (4) The hydrogen chloride and chlorine gas emission rates you use 
to calculate the HCl-equivalent emission rate limit for incinerators, 
cement kilns, and lightweight aggregate kilns must not result in total 
chlorine emission concentrations exceeding the standards provided by 
Sec. Sec.  63.1203, 63.1204, and 63.1205.
    (c) Eligibility demonstration--(1) General. You must perform an 
eligibility demonstration to determine whether your selected hydrogen 
chloride and chlorine gas emission rates meet the national exposure 
standards using either a look-up table analysis prescribed by paragraph 
(c)(3) of this section, or a site-specific compliance demonstration 
prescribed by paragraph (c)(4) of this section.
    (2) Definition of eligibility. Your facility is eligible for the 
alternative risk-based standards for total chlorine if either:
    (i) The sum of the calculated HCl-equivalent emission rates for all 
on-site hazardous waste combustors is below the appropriate value in 
the look-up table; or
    (ii) Your site-specific compliance demonstration indicates that 
your maximum Hazard Index for hydrogen chloride and chlorine gas 
emissions from all on-site hazardous waste combustors at a location 
where people live is less than or equal to 1.0, rounded to the nearest 
tenths decimal place (0.1).
    (3) Look-up table analysis. (i) The look-up table is provided as 
Table 1 to this section.
    (ii) To determine the correct HCl-equivalent emission rate value 
from the look-up table, you must use the average stack height for your 
hazardous waste combustors (i.e., the mean of the stack height of all 
on-site hazardous waste combustors) and the minimum distance between 
any hazardous waste combustor stack and the property boundary.
    (iii) If one or both of these values for stack height and distance 
to nearest property boundary do not match the exact values in the look-
up table, you would use the next lowest table value.
    (iv) You are not eligible for the look-up table analysis if your 
facility is located in complex terrain.
    (v) If the sum of the calculated HCl-equivalent emission rates for 
all on-site hazardous waste combustors is below the appropriate value 
in the look-up

[[Page 21373]]

table, the emission limit for total chlorine for each combustor is the 
HCl-equivalent emission rate you calculated.
    (4) Site-specific compliance demonstration. (i) You may use any 
scientifically-accepted peer-reviewed risk assessment methodology for 
your site-specific compliance demonstration. An example of one approach 
for performing the demonstration for air toxics can be found in the 
EPA's ``Air Toxics Risk Assessment Reference Library, Volume 2, Site-
Specific Risk Assessment Technical Resource Document,'' which may be 
obtained through the EPA's Air Toxics Web site at http://www.epa.gov/ttn/atw.
    (ii) Your facility is eligible for the alternative risk-based total 
chlorine emission limit if your site-specific compliance demonstration 
shows that the maximum Hazard Index for hydrogen chloride and chlorine 
gas emissions from each on-site hazardous waste combustor is less than 
or equal to 1.0 rounded to the nearest tenths decimal place (0.1).
    (iii) At a minimum, your site-specific compliance demonstration 
must:
    (A) Estimate long-term inhalation exposures through the estimation 
of annual or multi-year average ambient concentrations;
    (B) Estimate the inhalation exposure for the actual individual most 
exposed to the facility's emissions from hazardous waste combustors;
    (C) Use site-specific, quality-assured data wherever possible;
    (D) Use health-protective default assumptions wherever site-
specific data are not available, and:
    (E) Contain adequate documentation of the data and methods used for 
the assessment so that it is transparent and can be reproduced by an 
experienced risk assessor and emissions measurement expert.
    (iv) Your site-specific compliance demonstration need not:
    (A) Assume any attenuation of exposure concentrations due to the 
penetration of outdoor pollutants into indoor exposure areas;
    (B) Assume any reaction or deposition of the emitted pollutants 
during transport from the emission point to the point of exposure.
    (v) If your site-specific compliance demonstration documents that 
the maximum Hazard Index for hydrogen chloride and chlorine gas 
emissions from your hazardous waste combustors is less than or equal to 
1.0, you would establish a maximum HCl-equivalent emission rate limit 
for each combustor based on the hydrogen chloride and chlorine gas 
emission rates used in this site-specific compliance demonstration.
    (d) Review and approval of eligibility demonstrations--(1) Content 
of the eligibility demonstration--(i) General. The eligibility 
demonstration must include the following information, at a minimum:
    (A) Identification of each hazardous waste combustor combustion gas 
emission point (e.g., generally, the flue gas stack);
    (B) The maximum capacity at which each combustor will operate, and 
the maximum rated capacity for each combustor, using the metric of 
stack gas volume emitted per unit of time, as well as any other metric 
that is appropriate for the combustor (e.g., million Btu/hr heat input 
for boilers; tons of dry raw material feed/hour for cement kilns);
    (C) Stack parameters for each combustor, including, but not limited 
to stack height, stack area, stack gas temperature, and stack gas exit 
velocity;
    (D) Plot plan showing all stack emission points, nearby residences, 
and property boundary line;
    (E) Identification of any stack gas control devices used to reduce 
emissions from each combustor;
    (F) Identification of the RfC values used to calculate the HCl-
equivalent emissions rate;
    (G) Calculations used to determine the HCl-equivalent emission 
rate;
    (H) For incinerators, cement kilns, and lightweight aggregate 
kilns, calculations used to determine that the HCl-equivalent emission 
rate limit for each combustor does not exceed the standards for total 
chlorine at Sec. Sec.  63.1203, 63.1204, and 63.1205; and
    (I) The HCl-equivalent emission rate limit for each hazardous waste 
combustor that you will certify in the Documentation of Compliance 
required under Sec.  63.1211(d) that you will not exceed, and the 
limits on the operating parameters specified under Sec.  63.1209(o) 
that you will establish in the Documentation of Compliance.
    (ii) Additional content of look-up table demonstration. If you use 
the look-up table analysis, your eligibility demonstration must also 
contain, at a minimum, the following:
    (A) Calculations used to determine the average stack height of on-
site hazardous waste combustors;
    (B) Identification of the combustor stack with the minimum distance 
to the property boundary of the facility; and
    (C) Comparison of the values in the look-up table to your maximum 
HCl-equivalent emission rate.
    (iii) Additional content of a site-specific compliance 
demonstration. If you use a site-specific compliance demonstration, 
your eligibility demonstration must also contain, at a minimum, the 
following:
    (A) Identification of the risk assessment methodology used;
    (B) Documentation of the fate and transport model used;
    (C) Documentation of the fate and transport model inputs, including 
the stack parameters listed in paragraph (d)(1)(i)(C) of this section 
converted to the dimensions required for the model;
    (D) As applicable:
    (1) Meteorological data;
    (2) Building, land use, and terrain data;
    (3) Receptor locations and population data; and
    (4) Other facility-specific parameters input into the model;
    (E) Documentation of the fate and transport model outputs;
    (F) Documentation of any exposure assessment and risk 
characterization calculations; and,
    (G) Documentation of the predicted Hazard Index for HCl-equivalents 
and comparison to the limit of less than 1.0.
    (2) Review and approval--(i) Existing sources. (A) If you operate 
an existing source, you must be in compliance with the emission 
standards on the compliance date. If you elect to comply with the 
alternative risk-based emission rate limit for total chlorine, you must 
have completed the eligibility demonstration and received approval from 
your delegated permitting authority by the compliance date.
    (B) You must submit the eligibility demonstration to your 
permitting authority for review and approval not later than 12 months 
prior to the compliance date. You must submit a separate copy of the 
eligibility demonstration to: U.S. EPA, Risk and Exposure Assessment 
Group, Emission Standards Division (C404-01), Attn: Group Leader, 
Research Triangle Park, North Carolina 27711.
    (C) Your permitting authority will notify you of approval or intent 
to disapprove your eligibility demonstration within 6 months after 
receipt of the original demonstration, and within 3 months after 
receipt of any supplemental information that you submit. A notice of 
intent to disapprove your eligibility demonstration will identify 
incomplete or inaccurate information or noncompliance with prescribed 
procedures and specify how much time you will have to submit additional 
information.
    (D) If your permitting authority has not approved your eligibility 
demonstration to comply with a risk-based HCl-equivalent emission 
rate(s) by the compliance date, you must comply with the MACT emission

[[Page 21374]]

standards for total chlorine gas under Sec. Sec.  63.1216, 63.1217, 
63.1219, 63.1220, and 63.1221 of this chapter.
    (ii) New sources. General. (A) If you operate a source that is not 
an existing source and that becomes subject to subpart EEE, you must 
comply with the MACT emission standards for total chlorine unless and 
until your eligibility demonstration has been approved by the 
permitting authority.
    (B) If you operate a new or reconstructed source that starts up 
before the effective date of the emission standards proposed today, or 
a solid fuel-fired boiler or liquid fuel-fired boiler that is an area 
source that increases its emissions or its potential to emit such that 
it becomes a major source of HAP before the effective date of 
Sec. Sec.  63.1216 and 63.1217, you would be required to comply with 
the emission standards under Sec. Sec.  63.1216 and 63.1217 until your 
eligibility demonstration is approved by your permitting authority.
    (C) If you operate a new or reconstructed source that starts up 
after the effective date of the emission standards proposed today, or a 
solid fuel-fired boiler or liquid fuel-fired boiler that is an area 
source that increases its emissions or its potential to emit such that 
it becomes a major source of HAP after the effective date of Sec. Sec.  
63.1216 and 63.1217, you would be required to comply with the emission 
standards under Sec. Sec.  63.1216 and 63.1217 until your eligibility 
demonstration is approved by your permitting authority.
    (e) Testing and monitoring requirements--(1) General. You must 
document compliance during the comprehensive performance test under 
Sec.  63.1207 with the HCl-equivalent emission rate limit established 
in an approved eligibility demonstration for each hazardous waste 
combustor.
    (2) Test methods. (i) If you operate a cement kiln or a combustor 
equipped with a dry acid gas scrubber, you must should use EPA Method 
320/321 or ASTM D 6735-01, or an equivalent method, to measure hydrogen 
chloride, and the back-half (caustic impingers) of Method 26/26A, or an 
equivalent method, to measure chlorine gas.
    (ii) If you operate an incinerator, boiler, or lightweight 
aggregate kiln, you must use EPA Method 320/321 or ASTM D 6735-01, or 
an equivalent method, to measure hydrogen chloride, and Method 26/26A, 
or an equivalent method, to measure total chlorine, and calculate 
chlorine gas by difference if:
    (A) The bromine/chlorine ratio in feedstreams is greater than 5 
percent; or
    (B) The sulfur/chlorine ratio in feedstreams is greater than 50 
percent.
    (3) Operating parameter limits. (i) You must establish limits on 
the same operating parameters that apply to sources complying with the 
MACT standard for total chlorine under Sec.  63.1209(o), except that 
feedrate limits on total chlorine and chloride must be established as 
specified under paragraph (e)(3)(ii) of this section.
    (ii) Annual rolling average feedrate. You must establish an annual 
rolling average feedrate limit for total chlorine and chloride as the 
average of the test run averages during the comprehensive performance 
test.
    (A) To document compliance with the feedrate limit, you must know 
the total chlorine and chloride concentration of feedstreams at all 
times and continuously monitor the flowrate of all feedstreams.
    (B) You must measure the flowrate of each feedstream at least once 
each minute and update the annual rolling average hourly based on the 
average of the 60 previous 1-minute measurements.
    (f) Changes--(1) Changes over which you have control. (i) Changes 
in design, operation, or maintenance of a hazardous waste combustor 
that may affect the rate of emissions of HCl-equivalents from the 
combustor are subject to the requirements of Sec.  63.1206(b)(5).
    (ii) If you change the information documented in the demonstration 
of eligibility for the HCl-equivalent emission rate limit and which is 
used to establish the HCl-equivalent emission rate limit, you are 
subject to the following requirements:
    (A) Changes that would decrease the allowable HCl-equivalent 
emission rate limit. If you plan to make a change that would decrease 
the allowable HCl-equivalent emission rate limit documented in your 
eligibility demonstration, you must comply with Sec.  
63.1206(b)(5)(i)(A)-(C);
    (B) Changes that would not decrease the allowable HCl-equivalent 
emission rate limit. (1) If you determine that a change would not 
decrease the allowable HCl-equivalent emission rate limit documented in 
your eligibility demonstration, you must document the change in the 
operating record upon making such change.
    (2) If the change would increase your allowable HCl-equivalent 
emission rate limit and you elect to establish a higher HCl-equivalent 
limit, you must submit a revised eligibility demonstration for review 
and approval. Upon approval of the revised eligibility demonstration, 
you must comply with Sec.  63.1206(b)(5)(i)(A)(2), (B), and (C).
    (2) Changes over which you do not have control. (i) You must review 
the documentation you use in your eligibility demonstration every five 
years on the anniversary of the comprehensive performance test and 
submit for review and approval with the comprehensive performance test 
plan either a certification that the information used in your 
eligibility demonstration has not changed in a manner that would 
decrease the allowable HCl-equivalent emission rate limit, or a revised 
eligibility demonstration for a revised HCl-equivalent emission rate 
limit.
    (ii) If you determine that you cannot demonstrate compliance with a 
lower allowable HCl-equivalent emission rate limit during the 
comprehensive performance test because you cannot complete changes to 
the design or operation of the source prior to the test, you may 
request that the permitting authority grant you additional time as 
necessary to make those changes, not to exceed three years.

   Table 1. to Sec.   63.1215.--Allowable Toxicity-Weighted Emission Rate Expressed in HCL Equivalents (lb/hr)
----------------------------------------------------------------------------------------------------------------
                                                       Distance to property boundary (m)
        Stack ht  (m)        -----------------------------------------------------------------------------------
                                   10            30            50            100           200           500
----------------------------------------------------------------------------------------------------------------
2...........................        0.0244        0.0322        0.0338        0.0627         0.173         0.766
5...........................        0.0475        0.0612        0.0881        0.168          0.309         0.881
10..........................        0.165         0.187         0.216         0.336          0.637         1.59
20..........................        0.661         1.01          1.01          1.2            1.87          4.31
35..........................        2.02          2.02          4.04          4.11           5.08         10.4
50..........................        4.11          4.11          4.11          9.74          10.8          18.0
----------------------------------------------------------------------------------------------------------------


[[Page 21375]]

    13. Section 63.1216 and an undesignated center heading are added to 
subpart EEE to read as follows:

Emissions Standards and Operating Limits for Solid Fuel-Fired Boilers, 
Liquid Fuel-Fired Boilers, and Hydrochloric Acid Production Furnaces


Sec.  63.1216  What are the standards for solid fuel-fired boilers that 
burn hazardous waste?

    (a) Emission limits for existing sources. You must not discharge or 
cause combustion gases to be emitted into the atmosphere that contain:
    (1) For dioxin and furan, either carbon monoxide or hydrocarbon 
emissions in excess of the limits provided by paragraph (a)(5) of this 
section;
    (2) Mercury in excess of 10 ug/dscm corrected to 7 percent oxygen;
    (3) Except for an area source as defined in Sec.  63.2, cadmium and 
lead in excess of 170 ug/dscm, combined emissions, corrected to 7 
percent oxygen;
    (4) Except for an area source as defined in Sec.  63.2, arsenic, 
beryllium, and chromium in excess of 210 ug/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. If you elect to comply with this carbon monoxide 
standard rather than the hydrocarbon standard under paragraph 
(a)(5)(ii) of this section, you must also document that, during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec.  63.1206(b)(7), hydrocarbons do not exceed 10 parts 
per million by volume during those runs, 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
    (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) Except for an area source as defined in Sec.  63.2, hydrogen 
chloride and chlorine gas in excess of 440 parts per million by volume, 
combined emissions, expressed as a chloride (Cl(-)) 
equivalent, dry basis and corrected to 7 percent oxygen; and
    (7) Except for an area source as defined in Sec.  63.2, particulate 
matter in excess of 68 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 dioxin and furan, either carbon monoxide or hydrocarbon 
emissions in excess of the limits provided by paragraph (b)(5) of this 
section;
    (2) Mercury in excess of 10 [mu]g/dscm corrected to 7 percent 
oxygen;
    (3) Except for an area source as defined in Sec.  63.2, cadmium and 
lead in excess of 170 [mu]g/dscm, combined emissions, corrected to 7 
percent oxygen;
    (4) Except for an area source as defined in Sec.  63.2, arsenic, 
beryllium, and chromium in excess of 190 [mu]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. If you elect to comply with this carbon monoxide 
standard rather than the hydrocarbon standard under paragraph 
(b)(5)(ii) of this section, you must also document that, during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec. Sec.  63.1206(b)(7), hydrocarbons do not exceed 10 
parts per million by volume during those runs, 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
    (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) Except for an area source as defined in Sec.  63.2, hydrogen 
chloride and chlorine gas in excess of 73 parts per million by volume, 
combined emissions, expressed as a chloride (Cl(-)) 
equivalent, dry basis and corrected to 7 percent oxygen; and
    (7) Except for an area source as defined in Sec.  63.2, 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 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:

DRE = [1-(Wout / Win)] x 100%
Where:
Win = mass feedrate of one 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 
F020, F021, F022, F023, F026, or F027 (see Sec.  261.31 of this 
chapter), you must achieve a DRE of 99.9999% for each 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 tetra-, penta-, and hexachlorodibenzo-p-dioxins and dibenzofurans. 
You must use the equation in paragraph (c)(1) of this section to 
calculate DRE for each POHC. In addition, you must notify the 
Administrator of your intent to incinerate hazardous wastes F020, F021, 
F022, F023, F026, or F027.
    (3) Principal organic hazardous constituents (POHCs). (i) You must 
treat the 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.
    14. Section 63.1217 is added to subpart EEE to read as follows:


Sec.  63.1217  What are the standards for liquid fuel-fired boilers 
that burn hazardous waste?

    (a) Emission limits for existing sources. You must not discharge or 
cause combustion gases to be emitted into the atmosphere that contain:

[[Page 21376]]

    (1)(i) Dioxin and furan in excess of 0.40 ng TEQ/dscm corrected to 
7 percent oxygen for incinerators equipped with either a waste heat 
boiler or dry air pollution control system; or
    (ii) Either carbon monoxide or hydrocarbon emissions in excess of 
the limits provided by paragraph (a)(5) of this section for sources not 
equipped with either a waste heat boiler or dry air pollution control 
system;
    (iii) A source equipped a wet air pollution control system followed 
by a dry air pollution control system is not considered to be a dry air 
pollution control system, and a source equipped with a dry air 
pollution control system followed a wet air pollution control system is 
considered to be a dry air pollution control system for purposes of 
this emission limit;
    (2) Mercury in excess of 3.7 x 10-6 lbs mercury 
emissions attributable to the hazardous waste per million British 
thermal unit heat input from the hazardous waste;
    (3) Except for an area source as defined in Sec.  63.2, in excess 
of 1.1 x 10-5 lbs combined emissions of cadmium and lead 
attributable to the hazardous waste per million British thermal unit 
heat input from the hazardous waste;
    (4) Except for an area source as defined in Sec.  63.2, in excess 
of 1.1 x 10-4 lbs chromium emissions attributable to the 
hazardous waste per million British thermal unit heat input from the 
hazardous waste;
    (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. If you elect to comply with this carbon monoxide 
standard rather than the hydrocarbon standard under paragraph 
(a)(5)(ii) of this section, you must also document that, during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec.  63.1206(b)(7), hydrocarbons do not exceed 10 parts 
per million by volume during those runs, 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
    (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) Except for an area source as defined in Sec.  63.2, in excess 
of 2.5 x0-2 lbs combined emissions of hydrogen chloride and 
chlorine gas attributable to the hazardous waste per million British 
thermal unit heat input from the hazardous waste; and
    (7) Except for an area source as defined in Sec.  63.2 or as 
provided by paragraph (e)(2) of this section, particulate matter in 
excess of 59 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)(i) Dioxin and furan in excess of 0.015 ng TEQ/dscm corrected to 
7 percent oxygen for incinerators equipped with either a waste heat 
boiler or dry air pollution control system; or
    (ii) Either carbon monoxide or hydrocarbon emissions in excess of 
the limits provided by paragraph (a)(5) of this section for sources not 
equipped with either a waste heat boiler or dry air pollution control 
system;
    (iii) A source equipped a wet air pollution control system followed 
by a dry air pollution control system is not considered to be a dry air 
pollution control system, and a source equipped with a dry air 
pollution control system followed a wet air pollution control system is 
considered to be a dry air pollution control system for purposes of 
this emission limit;
    (2) In excess of 3.8 x 10-7 lbs mercury emissions 
attributable to the hazardous waste per million British thermal unit 
heat input from the hazardous waste;
    (3) Except for an area source as defined in Sec.  63.2, in excess 
of 4.3 x 10-6 lbs combined emissions of cadmium and lead 
attributable to the hazardous waste per million British thermal unit 
heat input from the hazardous waste;
    (4) Except for an area source as defined in Sec.  63.2, in excess 
of 3.6 x 10-5 lbs chromium emissions attributable to the 
hazardous waste per million British thermal unit heat input from the 
hazardous waste;
    (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. If you elect to comply with this carbon monoxide 
standard rather than the hydrocarbon standard under paragraph 
(a)(5)(ii) of this section, you must also document that, during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec.  63.1206(b)(7), hydrocarbons do not exceed 10 parts 
per million by volume during those runs, 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
    (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) Except for an area source as defined in Sec.  63.2, in excess 
of 7.2 x 10-4 lbs combined emissions of hydrogen chloride 
and chlorine gas attributable to the hazardous waste per million 
British thermal unit heat input from the hazardous waste; and
    (7) Except for an area source as defined in Sec.  63.2 or as 
provided in paragraph (e)(3) of this section, particulate matter in 
excess of 9.8 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 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:

DRE = [1-(Wout / Win)] x 100%
Where:
Win = mass feedrate of one 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 
F020, F021, F022, F023, F026, or F027 (see Sec.  261.31 of this 
chapter), you must achieve a DRE of 99.9999% for each 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 tetra-, penta-, and hexachlorodibenzo-p-dioxins and dibenzofurans. 
You must use the equation in paragraph (c)(1) of this section to 
calculate DRE for each POHC. In addition, you must notify the 
Administrator of your intent to incinerate hazardous wastes F020, F021, 
F022, F023, F026, or F027.
    (3) Principal organic hazardous constituents (POHCs). (i) You must 
treat the 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

[[Page 21377]]

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) Alternative to the particulate matter standard for liquid fuel-
fired boilers. (1) General. In lieu of complying with the applicable 
particulate matter standards of paragraphs (a)(7) and (b)(7) of this 
section, you may elect to comply with the following alternative metal 
emission control requirements:
    (2) Alternative metal emission control requirements for existing 
sources. (i) You must not discharge or cause combustion gases to be 
emitted into the atmosphere that contain in excess of 1.1 x 
10-5 lbs combined emissions of cadmium, lead, and selenium 
attributable to the hazardous waste per million British thermal unit 
heat input from the hazardous waste, corrected to 7 percent oxygen; 
and,
    (ii) You must not discharge or cause combustion gases to be emitted 
into the atmosphere that contain in excess of 7.7 x 10-5 lbs 
combined emissions of antimony, arsenic, beryllium, chromium, cobalt, 
manganese, and nickel attributable to the hazardous waste per million 
British thermal unit heat input from the hazardous waste, corrected to 
7 percent oxygen.
    (3) Alternative metal emission control requirements for new 
sources. (i) You must not discharge or cause combustion gases to be 
emitted into the atmosphere that contain in excess of 4.3 x 
10-6 lbs combined emissions of cadmium, lead, and selenium 
attributable to the hazardous waste per million British thermal unit 
heat input from the hazardous waste, corrected to 7 percent oxygen; 
and,
    (ii) You must not discharge or cause combustion gases to be emitted 
into the atmosphere that contain in excess of 3.6 x 10-5 lbs 
combined emissions of antimony, arsenic, beryllium, chromium, cobalt, 
manganese, and nickel attributable to the hazardous waste per million 
British thermal unit heat input from the hazardous waste, corrected to 
7 percent oxygen.
    15. Section 63.1218 is added to subpart EEE to read as follows:


Sec.  63.1218  What are the standards for hydrochloric acid production 
furnaces that burn hazardous waste?

    (a) Emission limits for existing sources. You must not discharge or 
cause combustion gases to be emitted into the atmosphere that contain:
    (1) Dioxin and furan emissions in excess of 0.40 ng TEQ/dscm, 
corrected to 7 percent oxygen;
    (2) For mercury, hydrogen chloride and chlorine gas emissions in 
excess of the levels provided by paragraph (a)(6) of this section;
    (3) For lead and cadmium, hydrogen chloride and chlorine gas 
emissions in excess of the levels provided by paragraph (a)(6) of this 
section;
    (4) For arsenic, beryllium, and chromium, hydrogen chloride and 
chlorine gas emissions in excess of the levels provided by paragraph 
(a)(6) of this section;
    (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. If you elect to comply with this carbon monoxide 
standard rather than the hydrocarbon standard under paragraph 
(a)(5)(ii) of this section, you must also document that, during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec.  63.1206(b)(7), hydrocarbons do not exceed 10 parts 
per million by volume during those runs, 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
    (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) For hydrogen chloride and chlorine gas, either:
    (i) Emission in excess of 14 parts per million by volume, combined 
emissions, expressed as a chloride (Cl(-) equivalent, dry 
basis and corrected to 7 percent oxygen; or
    (ii) Emissions greater than the levels that would be emitted if the 
source is achieving a system removal efficiency (SRE) of less than 
99.9927 percent for total chlorine and chloride fed to the combustor. 
You must calculate SRE from the following equation:

SRE = [1-(Cl out / Cl in)] X 100%

Where:

Clin = mass feedrate of total chlorine or chloride in all 
feedstreams, reported as chloride; and
Clout = mass emission rate of hydrogen chloride and chlorine 
gas, reported as chloride, in exhaust emissions prior to release to the 
atmosphere.

    (7) For particulate matter, hydrogen chloride and chlorine gas 
emissions in excess of the levels provided by paragraph (a)(6) of this 
section.
    (b) Emission limits for new sources. You must not discharge or 
cause combustion gases to be emitted into the atmosphere that contain:
    (1) Dioxin and furan emissions in excess of 0.40 ng TEQ/dscm, 
corrected to 7 percent oxygen;
    (2) For mercury, hydrogen chloride and chlorine gas emissions in 
excess of the levels provided by paragraph (a)(6) of this section;
    (3) For lead and cadmium, hydrogen chloride and chlorine gas 
emissions in excess of the levels provided by paragraph (a)(6) of this 
section;
    (4) For arsenic, beryllium, and chromium, hydrogen chloride and 
chlorine gas emissions in excess of the levels provided by paragraph 
(a)(6) of this section;
    (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. If you elect to comply with this carbon monoxide 
standard rather than the hydrocarbon standard under paragraph 
(b)(5)(ii) of this section, you must also document that, during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec.  63.1206(b)(7), hydrocarbons do not exceed 10 parts 
per million by volume during those runs, 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
    (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) For hydrochloric acid and chlorine gas, either:
    (i) Emission in excess of 1.2 parts per million by volume, combined 
emissions, expressed as a chloride

[[Page 21378]]

(Cl (-)) equivalent, dry basis and corrected to 7 percent 
oxygen; or
    (ii) Emissions greater than the levels that would be emitted if the 
source is achieving a system removal efficiency (SRE) of less than 
99.99937 percent for total chlorine and chloride fed to the combustor. 
You must calculate SRE from the following equation:

SRE = [1-(Cl out / Cl in)] x 100%
Where:

Cl in = mass feedrate of total chlorine or chloride in all 
feedstreams, reported as chloride; and
Cl out = mass emission rate of hydrogen chloride and 
chlorine gas, reported as chloride, in exhaust emissions prior to 
release to the atmosphere.

    (7) For particulate matter, hydrogen chloride and chlorine gas 
emissions in excess of the levels provided by paragraph (a)(6) 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 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:

DRE = [1-(Wout / Win)] x 100%

Where:

    Win = mass feedrate of one 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 
F020, F021, F022, F023, F026, or F027 (see Sec.  261.31 of this 
chapter), you must achieve a DRE of 99.9999% for each 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 tetra-, penta-, and hexachlorodibenzo-p-dioxins and dibenzofurans. 
You must use the equation in paragraph (c)(1) of this section to 
calculate DRE for each POHC. In addition, you must notify the 
Administrator of your intent to incinerate hazardous wastes F020, F021, 
F022, F023, F026, or F027.
    (3) Principal organic hazardous constituents (POHCs). (i) You must 
treat the 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.
    16. Section 63.1219 and a new undesignated center heading are added 
to subpart EEE to read as follows:

Replacement Emissions Standards and Operating Limits for Incinerators, 
Cement Kilns, and Lightweight Aggregate Kilns


Sec.  63.1219  What are the replacement standards for hazardous waste 
incinerators?

    (a) Emission limits for existing sources. You must not discharge or 
cause combustion gases to be emitted into the atmosphere that contain:
    (1)(i) Dioxin and furan in excess of 0.28 ng TEQ/dscm corrected to 
7 percent oxygen for incinerators equipped with either a waste heat 
boiler or dry air pollution control system; or
    (ii) Dioxin and furan in excess of 0.40 ng TEQ/dscm corrected to 7 
percent oxygen for sources not equipped with either a waste heat boiler 
or dry air pollution control system;
    (iii) A source equipped a wet air pollution control system followed 
by a dry air pollution control system is not considered to be a dry air 
pollution control system, and a source equipped with a dry air 
pollution control system followed a wet air pollution control system is 
considered to be a dry air pollution control system for purposes of 
this emission limit;
    (2) Mercury in excess of 130 [mu]g/dscm corrected to 7 percent 
oxygen;
    (3) Cadmium and lead in excess of 59 [mu]g/dscm, combined 
emissions, corrected to 7 percent oxygen;
    (4) Arsenic, beryllium, and chromium in excess of 84 [mu]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. If you elect to comply with this carbon monoxide 
standard rather than the hydrocarbon standard under paragraph 
(a)(5)(ii) of this section, you must also document that, during the 
destruction and removal efficiency (DRE) test runs or their equivalent 
as provided by Sec.  63.1206(b)(7), hydrocarbons do not exceed 10 parts 
per million by volume during those runs, 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
    (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) Hydrogen chloride and chlorine gas (total chlorine) in excess 
of 1.5 parts per million by volume, combined emissions, expressed as a 
chloride (Cl(-)) equivalent, dry basis and corrected to 7 
percent oxygen; and
    (7) Except as provided by paragraph (e)(2) of this section, 
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)(i) Dioxin and furans in excess of 0.11 ng TEQ/dscm corrected to 
7 percent oxygen for incinerators equipped with either a waste heat 
boiler or dry air pollution control system; or
    (ii) Dioxin and furans in excess of 0.20 ng TEQ/dscm corrected to 7 
percent oxygen for sources not equipped with either a waste heat boiler 
or dry air pollution control system;
    (iii) A source equipped a wet air pollution control system followed 
by a dry air pollution control system is not considered to be a dry air 
pollution control system, and a source equipped with a dry air 
pollution control system followed a wet air pollution control system is 
considered to be a dry air pollution control system for purposes of 
this standard;
    (2) Mercury in excess of 8 [mu]g/dscm corrected to 7 percent 
oxygen;
    (3) Cadmium and lead in excess of 6.5 [mu]g/dscm, combined 
emissions, corrected to 7 percent oxygen;
    (4) Arsenic, beryllium, and chromium in excess of 8.9 [mu]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

[[Page 21379]]

hourly rolling average (monitored continuously with a continuous 
emissions monitoring system), dry basis and corrected to 7 percent 
oxygen. If you elect to comply with this carbon monoxide standard 
rather than the hydrocarbon standard under paragraph (b)(5)(ii) of this 
section, you must also document that, during the destruction and 
removal efficiency (DRE) test runs or their equivalent as provided by 
Sec.  63.1206(b)(7), hydrocarbons do not exceed 10 parts per million by 
volume during those runs, 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
    (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) Hydrogen chloride and chlorine gas in excess of 0.18 parts per 
million by volume, combined emissions, expressed as a chloride 
(Cl(-)) equivalent, dry basis and corrected to 7 percent 
oxygen; and
    (7) Except as provided by paragraph (e)(3) of this section, 
particulate matter in excess of 1.6 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:

DRE = [1 - (Wout / Win )] x 100%

Where:
Win = mass feedrate of one 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 
F020, F021, F022, F023, F026, or F027 (see Sec.  261.31 of this 
chapter), you must achieve a DRE of 99.9999% for each 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 tetra-, penta-, and hexachlorodibenzo-p-dioxins and dibenzofurans. 
You must use the equation in paragraph (c)(1) of this section to 
calculate DRE for each POHC. In addition, you must notify the 
Administrator of your intent to incinerate hazardous wastes F020, F021, 
F022, F023, F026, or F027.
    (3) Principal organic hazardous constituent (POHC). (i) You must 
treat each POHC 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) Alternative to the particulate matter standard for 
incinerators--(1) General. In lieu of complying with the applicable 
particulate matter standards of paragraphs (a)(7) and (b)(7) of this 
section, you may elect to comply with the following alternative metal 
emission control requirements:
    (2) Alternative metal emission control requirements for existing 
sources. (i) You must not discharge or cause combustion gases to be 
emitted into the atmosphere that contain cadmium, lead, and selenium in 
excess of 59 [mu]g/dscm, combined emissions, corrected to 7 percent 
oxygen; and,
    (ii) You must not discharge or cause combustion gases to be emitted 
into the atmosphere that contain antimony, arsenic, beryllium, 
chromium, cobalt, manganese, and nickel in excess of 84 [mu]g/dscm, 
combined emissions, corrected to 7 percent oxygen.
    (3) Alternative metal emission control requirements for new 
sources. (i) You must not discharge or cause combustion gases to be 
emitted into the atmosphere that contain cadmium, lead, and selenium in 
excess of 6.5/dscm, combined emissions, corrected to 7 percent oxygen; 
and,
    (ii) You must not discharge or cause combustion gases to be emitted 
into the atmosphere that contain antimony, arsenic, beryllium, 
chromium, cobalt, manganese, and nickel in excess of 8.9 [mu]g/dscm, 
combined emissions, corrected to 7 percent oxygen.
    17. Section 63.1220 is added to subpart EEE to read as follows:


Sec.  63.1220  What are the replacement 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)(i) Dioxin and furan in excess of 0.20 ng TEQ/dscm corrected to 
7 percent oxygen; or
    (ii) Dioxin and furan 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 64 [mu]g/dscm corrected to 7 percent 
oxygen;
    (3) In excess of 4.0 x 10-4 lbs combined emissions of 
cadmium and lead attributable to the hazardous waste per million 
British thermal unit heat input from the hazardous waste;
    (4) In excess of 1.4 x 10-5 lbs combined emissions of 
arsenic, beryllium, and chromium attributable to the hazardous waste 
per million British thermal unit heat input from the hazardous waste;
    (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 mid-kiln 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. If you 
elect to comply with this carbon monoxide standard rather than the 
hydrocarbon standard under paragraph (a)(5)(i)(B) of this section, you 
must also document that, during the destruction and removal efficiency 
(DRE) test runs or their equivalent as provided by Sec.  63.1206(b)(7), 
hydrocarbons in the by-pass duct or mid-kiln gas sampling system do not 
exceed 10 parts per million by volume during those runs, 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) 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

[[Page 21380]]

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. If you elect to comply with this 
carbon monoxide standard rather than the hydrocarbon standard under 
paragraph (a)(5)(ii)(A) of this section, you also must document that, 
during the destruction and removal efficiency (DRE) test runs or their 
equivalent as provided by Sec.  63.1206(b)(7), hydrocarbons in the main 
stack do not exceed 20 parts per million by volume during those runs, 
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) Hydrogen chloride and chlorine gas in excess of 110 parts per 
million by volume, combined emissions, expressed as a chloride 
(Cl(-)) equivalent, dry basis, corrected to 7 percent 
oxygen; and
    (7) Particulate matter in excess of 65 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)(i) Dioxin and furan in excess of 0.20 ng TEQ/dscm corrected to 
7 percent oxygen; or
    (ii) Dioxin and furan 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 35 [mu]g/dscm corrected to 7 percent 
oxygen;
    (3) In excess of 6.2 x 10-5 lbs combined emissions of 
cadmium and lead attributable to the hazardous waste per million 
British thermal unit heat input from the hazardous waste;
    (4) In excess of 1.4 x 10-5 lbs combined emissions of 
arsenic, beryllium, and chromium attributable to the hazardous waste 
per million British thermal unit heat input from the hazardous waste;
    (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. If you elect to comply with this carbon monoxide 
standard rather than the hydrocarbon standard under paragraph 
(b)(5)(i)(A)(2) of this section, you also must document that, during 
the destruction and removal efficiency (DRE) test runs or their 
equivalent as provided by Sec.  63.1206(b)(7), hydrocarbons do not 
exceed 10 parts per million by volume during those runs, 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
    (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 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 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
    (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) Hydrogen chloride and chlorine gas in excess of 78 parts per 
million, combined emissions, expressed as a chloride (Cl(-)) 
equivalent, dry basis and corrected to 7 percent oxygen; and
    (7) Particulate matter in excess of 13 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:

DRE = [1 - (Wout / Win )] x 100%

Where:

Win = mass feedrate of one 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 
F020, F021, F022, F023, F026, or F027 (see Sec.  261.31 of this 
chapter), you must achieve a DRE of 99.9999% for each 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 tetra-, penta-, and hexachlorodibenzo-p-dioxins and dibenzofurans. 
You must use the equation in paragraph (c)(1) of this section to 
calculate DRE for each POHC. In addition, you must notify the 
Administrator of your intent to incinerate hazardous wastes F020, F021, 
F022, F023, F026, or F027.

[[Page 21381]]

    (3) Principal organic hazardous constituent (POHC). (i) You must 
treat each POHC 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. The provisions of 
Sec.  63.1204(d) apply.
    (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:

Ctotal = {Cmill-off x (Tmill-off/
(Tmill-off + Tmill-on)){time}  + 
{Cmill-on x (Tmill-on/(Tmill-off + 
Tmill-on )){time} 

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; and
Tmill-on = time when kiln gases are routed through the raw 
mill.

    (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:

Ctot = {Cmain x (Qmain/
(Qmain + Qbypass)){time}  + {Cbypass x 
(Qbypass/(Qmain + Qbypass)){time} 

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; and
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) [Reserved].
    (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.

[[Page 21382]]

    18. Section 63.1221 is added to subpart EEE to read as follows:


Sec.  63.1221  What are the replacement 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) Dioxins and furans in excess of 0.40 ng TEQ/dscm corrected to 7 
percent oxygen;
    (2) Mercury in excess of 67 [mu]g/dscm corrected to 7 percent 
oxygen;
    (3)(i) In excess of 3.1 x 10-\4\ lbs combined emissions 
of cadmium and lead attributable to the hazardous waste per million 
British thermal unit heat input from the hazardous waste; and
    (ii) Lead and cadmium in excess of 250 [mu]g/dscm, combined 
emissions, corrected to 7 percent oxygen;
    (4)(ii) In excess of 9.5 x 10-\5\ lbs combined emissions 
of arsenic, beryllium, and chromium attributable to the hazardous waste 
per million British thermal unit heat input from the hazardous waste; 
and
    (ii) Arsenic, beryllium, and chromium in excess of 110 [mu]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. If you elect to comply 
with this carbon monoxide standard rather than the hydrocarbon standard 
under paragraph (a)(5)(ii) of this section, you also must document 
that, during the destruction and removal efficiency (DRE) test runs or 
their equivalent as provided by Sec.  63.1206(b)(7), hydrocarbons do 
not exceed 20 parts per million by volume during those runs, 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
    (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) Hydrogen chloride and chlorine gas in excess of 600 parts per 
million by volume, combined emissions, expressed as a chloride 
(Cl(-)) equivalent, dry 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) Dioxins and furans in excess of 0.40 ng TEQ/dscm corrected to 7 
percent oxygen;
    (2) Mercury in excess of 67 [mu]g/dscm corrected to 7 percent 
oxygen;
    (3)(i) In excess of 2.4 x 10-\5\ lbs combined emissions 
of cadmium and lead attributable to the hazardous waste per million 
British thermal unit heat input from the hazardous waste; and
    (ii) Lead and cadmium in excess of 43 [mu]g/dscm, combined 
emissions, corrected to 7 percent oxygen;
    (4)(i) In excess of 3.2 x 10-\5\ lbs combined emissions 
of arsenic, beryllium, and chromium attributable to the hazardous waste 
per million British thermal unit heat input from the hazardous waste; 
and
    (ii) Arsenic, beryllium, and chromium in excess of 110 [mu]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. If you elect to comply 
with this carbon monoxide standard rather than the hydrocarbon standard 
under paragraph (b)(5)(ii) of this section, you also must document 
that, during the destruction and removal efficiency (DRE) test runs or 
their equivalent as provided by Sec.  63.1206(b)(7), hydrocarbons do 
not exceed 20 parts per million by volume during those runs, 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
    (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) Hydrogen chloride and chlorine gas in excess of 600 parts per 
million by volume, combined emissions, expressed as a chloride 
(Cl-) equivalent, dry basis and corrected to 7 percent 
oxygen; and
    (7) Particulate matter in excess of 23 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:

DRE = [1- (Wout / Win)] x 100%

Where:

Win = mass feedrate of one 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 
F020, F021, F022, F023, F026, or F027 (see Sec.  261.31 of this 
chapter), you must achieve a destruction and removal efficiency (DRE) 
of 99.9999% for each 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 tetra-, penta-, and 
hexachlorodibenzo-dioxins and dibenzofurans. You must use the equation 
in paragraph (c)(1) of this section to calculate DRE for each POHC. In 
addition, you must notify the Administrator of your intent to burn 
hazardous wastes F020, F021, F022, F023, F026, or F027.
    (3) Principal organic hazardous constituents (POHCs). (i) You must 
treat each POHC 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.

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, 6925, 6927, 6928(h), 
and 6974.


[[Page 21383]]


    2. Section 264.340 is amended by revising the first sentence of 
paragraph (b)(1) and adding paragraph (b)(5) to read as follows:


Sec.  264.340  Applicability.

* * * * *
    (b) * * * (1) Except as provided by paragraphs (b)(2) through 
(b)(5) 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 
Sec. Sec.  63.1207(j) and 63.1210(d) of this chapter documenting 
compliance with the requirements of part 63, subpart EEE, of this 
chapter. * * *
* * * * *
    (5) The particulate matter standard of Sec.  264.343(c) remains in 
effect for incinerators that elect to comply with the alternative to 
the particulate matter standard of Sec.  63.1219(e) of this chapter.
* * * * *

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 revising paragraph (b)(1) to read 
as follows:


Sec.  265.340  Applicability.

* * * * *
    (b) * * * (1) Except as provided by paragraphs (b)(2) and (b)(3) 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 Sec. Sec.  63.1207(j) 
and 63.1210(d) of this chapter documenting compliance with the 
requirements of part 63, subpart EEE, of this chapter.
* * * * *

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: 42 U.S.C. 1006, 2002(a), 3001-3009, 3014, 6905, 6906, 
6912, 6921, 6922, 6924-6927, 6934, and 6937.

    2. Section 266.100 is amended by revising the first sentence of 
paragraph (b)(1) and adding paragraph (b)(3) to read as follows:


Sec.  266.100  Applicability.

* * * * *
    (b) * * * (1) Except as provided by paragraphs (b)(2) and (b)(3) 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 Sec. Sec.  63.1207(j) 
and 63.1210(d) of this chapter documenting compliance with the 
requirements of part 63, subpart EEE, of this chapter. * * *
* * * * *
    (3) If you own or operate a boiler or hydrochloric acid furnace 
that is an area source under Sec.  63.2 of this chapter and you elect 
not to comply with the emission standards under Sec. Sec.  63.1216, 
63.1217, and 63.1218 of this chapter for particulate matter, 
semivolatile and low volatile metals, and total chlorine, you also 
remain subject to:
    (i) Section 266.105--Standards to control particulate matter;
    (ii) Section 266.106--Standards to control metals emissions, except 
for mercury; and
    (iii) Section 266.107--Standards to control hydrogen chloride and 
chlorine gas.
* * * * *

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 270.10 is amended by adding paragraph (l) to read as 
follows:


Sec.  270.10  General application requirements.

* * * * *
    (l) If the Director concludes that there is reason to believe that 
compliance with the standards in 40 CFR part 63, subpart EEE alone may 
not be protective of human health or the environment, the Director 
shall require additional information or assessment(s) that the Director 
determines are necessary to ensure protection of human health and the 
environment. The Director also may require a permittee or an applicant 
to provide information necessary to determine whether such an 
assessment(s) should be required.
    3. Section 270.19 is amended by revising paragraph (e) to read as 
follows:


Sec.  270.19  Specific part B information requirements for 
incinerators.

* * * * *
    (e) When an owner or operator demonstrates compliance with the air 
emission standards and limitations in part 63, subpart EEE, of this 
chapter (i.e., by conducting a comprehensive performance test and 
submitting a Notification of Compliance under Sec. Sec.  63.1207(j) and 
63.1210(d) of this chapter documenting compliance with all applicable 
requirements of part 63, subpart EEE, of this chapter), the 
requirements of this section do not apply, except those provisions the 
Director determines are necessary to ensure compliance with Sec. Sec.  
264.345(a) and 264.345(c) of this chapter if you elect to comply with 
Sec.  270.235(a)(1)(i) to minimize emissions of toxic compounds from 
startup, shutdown, and malfunction events. Nevertheless, the Director 
may apply the provisions of this section, on a case-by-case basis, for 
purposes of information collection in accordance with Sec. Sec.  
270.10(k), 270.10(l), 270.32(b)(2), and 270.32(b)(3) of this chapter.
    3. Section 270.22 is amended by revising the introductory text to 
read as follows:


Sec.  270.22  Specific part B information requirements for boilers and 
industrial furnaces burning hazardous waste.

    When an owner or operator of a cement kiln, lightweight aggregate 
kiln, solid fuel-fired boiler, liquid fuel-fired boiler, or 
hydrochloric acid production furnace demonstrates compliance with the 
air emission standards and limitations in part 63, subpart EEE, of this 
chapter (i.e., by conducting a comprehensive performance test and 
submitting a Notification of Compliance under Sec. Sec.  63.1207(j) and 
63.1210(d) of this chapter documenting compliance with all applicable 
requirements of part 63, subpart EEE, of this chapter), the 
requirements of this section do not apply. The requirements of this 
section

[[Page 21384]]

do apply, however, if the Director determines certain provisions are 
necessary to ensure compliance with Sec. Sec.  266.102(e)(1) and 
266.102(e)(2)(iii) of this chapter if you elect to comply with Sec.  
270.235(a)(1)(i) to minimize emissions of toxic compounds from startup, 
shutdown, and malfunction events; or if you are an area source and 
elect to comply with the Sec. Sec.  266.105, 266.106, and 266.107 
standards and associated requirements for particulate matter, hydrogen 
chloride and chlorine gas, and non-mercury metals; or the Director 
determines certain provisions apply, on a case-by-case basis, for 
purposes of information collection in accordance with Sec. Sec.  
270.10(k), 270.10(l), 270.32(b)(2), and 270.32(b)(3).
* * * * *
    4. Section 270.32 is amended by adding paragraph (b)(3) to read as 
follows:


Sec.  270.32  Establishing permit conditions.

* * * * *
    (b) * * *
    (3) If, as the result of an assessment(s) or other information, the 
Administrator or Director determines that conditions are necessary in 
addition to those required under 40 CFR parts 63, subpart EEE, 264 or 
266 to ensure protection of human health and the environment, he shall 
include those terms and conditions in a RCRA permit for a hazardous 
waste combustion unit.
* * * * *
    5. Section 270.42 is amended by:
    a. Revising paragraph (j)(1).
    b. Redesignating paragraph (j)(2) as (j)(3).
    c. Adding new paragraph (j)(2).
    d. Adding new paragraph (k); and
    e. Adding a new entry 10 in numerical order in the table under 
section L of Appendix I.
    The revisions and additions reads as follows:


Sec.  270.42  Permit modification at the request of the permittee.

* * * * *
    (j) * * *
    (1) Facility owners or operators must have complied with the 
Notification of Intent to Comply (NIC) requirements of 40 CFR 63.1210 
that were in effect prior to October 11, 2000, (See 40 CFR part 63 
Sec. Sec.  63.1200-63.1499 revised as of July 1, 2000) in order to 
request a permit modification under this section for the purpose of 
technology changes needed to meet the 40 CFR 63.1203, 63.1204, and 
63.1205 standards.
    (2) Facility owners or operators must comply with the Notification 
of Intent to Comply (NIC) requirements of 40 CFR 63.1210(b) and 63.1212 
before a permit modification can be requested under this section for 
the purpose of technology changes needed to meet the 40 CFR 63.1215, 
63.1216, 63.1217, 63.1218, 63.1219, 63.1220, and 63.1221 standards 
promulgated on [date of publication of the final rule in the Federal 
Register].
* * * * *
    (k) Waiver of RCRA permitting requirements in support of transition 
to the part 63 MACT standards. (1) You may request to have specific 
RCRA operating and emissions limits waived by submitting a Class 1 
permit modification request under Appendix I of this section, section 
L(10). You must:
    (i) Identify the specific RCRA permit operating and emissions 
limits which you are requesting to waive;
    (ii) Provide an explanation of why the changes are necessary in 
order to minimize or eliminate conflicts between the RCRA permit and 
MACT compliance; and
    (iii) Discuss how the revised provisions will be sufficiently 
protective.
    (2) To request this modification in conjunction with MACT 
performance testing where permit limits may only be waived during 
actual test events and pretesting, as defined under 40 CFR 
63.1207(h)(2)(i) and (ii), for an aggregate time not to exceed 720 
hours of operation (renewable at the discretion of the Administrator) 
you must:
    (i) Demonstrate that your site-specific emissions test plan and 
continuous monitoring system performance evaluation test plan have been 
submitted and approved by the Administrator as required in 40 CFR 
63.1207(e), and
    (ii) Submit your modification request upon approval of your test 
plan.
    (3) The Director shall approve or deny the request within 30 days 
of receipt of the request. The Director may, at his or her discretion, 
extend this 30 day deadline one time for up to 30 days by notifying the 
facility owner or operator.
* * * * *

   Appendix I to Sec.   270.42--Classification of Permit Modification
------------------------------------------------------------------------
                          Modifications                            Class
------------------------------------------------------------------------
 
                                * * * * *
10. Changes to RCRA permit provisions needed to support            \1\ 1
 transition to 40 CFR part 63 (Subpart EEE--National Emission
 Standards for Hazardous Air Pollutants From Hazardous Waste
 Combustors), provided the procedures of Sec.   270.42(k) are
 followed.......................................................
 
                               * * * * *
------------------------------------------------------------------------
\1\ Class 1 modifications requiring prior Agency approval.

    6. Section 270.62 is amended by revising the 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 part 63, subpart EEE, of this 
chapter (i.e., by conducting a comprehensive performance test and 
submitting a Notification of Compliance under Sec. Sec.  63.1207(j) and 
63.1210(d) of this chapter documenting compliance with all applicable 
requirements of part 63, subpart EEE, of this chapter), the 
requirements of this section do not apply, except those provisions the 
Director determines are necessary to ensure compliance with Sec. Sec.  
264.345(a) and 264.345(c) of this chapter if you elect to comply with 
Sec.  270.235(a)(1)(i) to minimize emissions of toxic compounds from 
startup, shutdown, and malfunction events. Nevertheless, the Director 
may apply the provisions of this section, on a case-by-case basis, for 
purposes of information collection in accordance with Sec. Sec.  
270.10(k), 270.10(l), 270.32(b)(2), and 270.32(b)(3) of this chapter.
* * * * *
    7. Section 270.66 is amended by revising the 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 kiln, lightweight aggregate 
kiln, solid fuel-fired boiler, liquid fuel-fired boiler, or 
hydrochloric acid production furnace demonstrates compliance with the 
air emission standards and limitations in part 63, subpart EEE, of this 
chapter (i.e., by conducting a comprehensive performance test and 
submitting a Notification of Compliance under Sec. Sec.  63.1207(j) and 
63.1210(d) of this chapter documenting compliance with all applicable 
requirements of part 63, subpart EEE, of this chapter), the 
requirements of this section do not apply. The requirements of this 
section do apply, however, if the Director determines certain 
provisions are necessary to ensure compliance with Sec. Sec.  
266.102(e)(1) and 266.102(e)(2)(iii) of

[[Page 21385]]

this chapter if you elect to comply with Sec.  270.235(a)(1)(i) to 
minimize emissions of toxic compounds from startup, shutdown, and 
malfunction events; or if you are an area source and elect to comply 
with the Sec. Sec.  266.105, 266.106, and 266.107 standards and 
associated requirements for particulate matter, hydrogen chloride and 
chlorine gas, and non-mercury metals; or the Director determines 
certain provisions apply, on a case-by-case basis, for purposes of 
information collection in accordance with Sec. Sec.  270.10(k), 
270.10(l), 270.32(b)(2), and 270.32(b)(3).
* * * * *
    8. Section 270.235 is amended by:
    a. Revising paragraphs (a)(1) introductory text and (a)(2) 
introductory text.
    b. Revising paragraphs (b)(1) introductory text and (b)(2).
    The revisions read as follows:


Sec.  270.235  Options for incinerators, cement kilns, lightweight 
aggregate kilns, solid fuel-fired boilers, liquid fuel-fired boilers 
and hydrochloric acid production furnaces to minimize emissions from 
startup, shutdown, and malfunction events.

    (a) * * * (1) Revisions to permit conditions after documenting 
compliance with MACT. The owner or operator of a RCRA-permitted 
incinerator, cement kiln, lightweight aggregate kiln, solid fuel-fired 
boiler, liquid fuel-fired boiler, or hydrochloric acid production 
furnace may request that the Director address permit conditions that 
minimize emissions from startup, shutdown, and malfunction events under 
any of the following options when requesting removal of permit 
conditions that are no longer applicable according to Sec. Sec.  
264.340(b) and 266.100(b) of this chapter:
* * * * *
    (2) Addressing permit conditions upon permit reissuance. The owner 
or operator of an incinerator, cement kiln, lightweight aggregate kiln, 
solid fuel-fired boiler, liquid fuel-fired boiler, or hydrochloric acid 
production furnace that has conducted a comprehensive performance test 
and submitted to the Administrator a Notification of Compliance 
documenting compliance with the standards of part 63, subpart EEE, of 
this chapter may request in the application to reissue the permit for 
the combustion unit that the Director control emissions from startup, 
shutdown, and malfunction events under any of the following options:
* * * * *
    (b) * * * (1) Interim status operations. In compliance with 
Sec. Sec.  265.340 and 266.100(b), the owner or operator of an 
incinerator, cement kiln, lightweight aggregate kiln, solid fuel-fired 
boiler, liquid fuel-fired boiler, or hydrochloric acid production 
furnace that is operating under the interim status standards of part 
265 or 266 of this chapter may control emissions of toxic compounds 
during startup, shutdown, and malfunction events under either of the 
following options after conducting a comprehensive performance test and 
submitting to the Administrator a Notification of Compliance 
documenting compliance with the standards of part 63, subpart EEE, of 
this chapter.
* * * * *
    (2) Operations under a subsequent RCRA permit. When an owner or 
operator of an incinerator, cement kiln, lightweight aggregate kiln, 
solid fuel-fired boiler, liquid fuel-fired boiler, or hydrochloric acid 
production furnace that is operating under the interim status standards 
of parts 265 or 266 of this chapter submits a RCRA permit application, 
the owner or operator may request that the Director control emissions 
from startup, shutdown, and malfunction events under any of the options 
provided by paragraphs (a)(2)(i), (a)(2)(ii), or (a)(2)(iii) of this 
section.
* * * * *

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 entry 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
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Insert date of publication of final   Standards for Hazardous  [Insert FR page numbers   [Insert date of
 rule in the Federal Register (FR)].   Air Pollutants for       of final rule].           publication of final
                                       Hazardous Waste                                    rule].
                                       Combustors.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 04-7858 Filed 4-19-04; 8:45 am]
BILLING CODE 6560-50-P