[Federal Register Volume 79, Number 127 (Wednesday, July 2, 2014)]
[Proposed Rules]
[Pages 37850-37895]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-13490]



[[Page 37849]]

Vol. 79

Wednesday,

No. 127

July 2, 2014

Part II





Environmental Protection Agency





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40 CFR Part 63





National Emission Standards for Hazardous Air Pollutants: Off-Site 
Waste and Recovery Operations; Proposed Rule

  Federal Register / Vol. 79 , No. 127 / Wednesday, July 2, 2014 / 
Proposed Rules  

[[Page 37850]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2012-0360; FRL-9911-93-0A]
RIN 2060-AR47


National Emission Standards for Hazardous Air Pollutants: Off-
Site Waste and Recovery Operations

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing 
amendments to the national emission standards for hazardous air 
pollutants (NESHAP) for off-site waste and recovery operations (OSWRO) 
to address the results of the residual risk and technology review (RTR) 
conducted under the Clean Air Act (CAA). In light of our residual risk 
and technology review, we are proposing to amend the requirements for 
leak detection and repair and the requirements for certain tanks. In 
addition, the EPA is proposing amendments to revise regulatory 
provisions pertaining to emissions during periods of startup, shutdown 
and malfunction; add requirements for electronic reporting of 
performance test results; revise the routine maintenance provisions; 
clarify provisions pertaining to open-ended valves and lines; add 
monitoring requirements for pressure relief devices; clarify provisions 
for some performance test methods and procedures; and make several 
minor clarifications and corrections.

DATES: 
    Comments. Comments must be received on or before August 18, 2014. A 
copy of comments on the information collection provisions should be 
submitted to the Office of Management and Budget (OMB) on or before 
August 1, 2014.
    Public Hearing. We do not plan to conduct a public hearing unless 
requested. If requested, we will hold a public hearing on July 17, 
2014. To request a hearing, please contact the person listed in the 
following FOR FURTHER INFORMATION CONTACT section by July 14, 2014.

ADDRESSES:
    Comments. Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2012-0360, by one of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov. 
Follow the online instructions for submitting comments.
     Email: [email protected]. Include Docket ID No. EPA-
HQ-OAR-2012-0360 in the subject line of the message.
     Fax: (202) 566-9744, Attention Docket ID No. EPA-HQ-OAR-
2012-0360.
     Mail: Environmental Protection Agency, EPA Docket Center 
(EPA/DC), Mail Code 28221T, Attention Docket ID No. EPA-HQ-OAR-2012-
0360, 1200 Pennsylvania Avenue NW., Washington, DC 20460. Please 
include a total of two copies. In addition, please mail a copy of your 
comments on the information collection provisions to the Office of 
Information and Regulatory Affairs, Office of Management and Budget 
(OMB), Attn: Desk Officer for EPA, 725 17th Street NW., Washington, DC 
20503.
     Hand/Courier Delivery: EPA Docket Center, Room 3334, EPA 
WJC West Building, 1301 Constitution Avenue NW., Washington, DC 20004, 
Attention Docket ID No. EPA-HQ-OAR-2012-0360. 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. EPA-HQ-OAR-
2012-0360. The 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.regulations.gov, 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 http://www.regulations.gov or email. The http://www.regulations.gov Web site 
is an ``anonymous access'' system, which means the EPA will not know 
your identity or contact information unless you provide it in the body 
of your comment. If you send an email comment directly to the EPA 
without going through http://www.regulations.gov, your email 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, the 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 the EPA cannot read your comment 
due to technical difficulties and cannot contact you for clarification, 
the EPA may not be able to consider your comment. Electronic files 
should not include special characters or any form of encryption and be 
free of any defects or viruses. For additional information about the 
EPA's public docket, visit the EPA Docket Center homepage at: http://www.epa.gov/dockets.
    Docket. The EPA has established a docket for this proposed rule 
under Docket ID No. EPA-HQ-OAR-2012-0360. All documents in the docket 
are listed in the regulations.gov index. Although listed in the index, 
some information is not publicly available, e.g., 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. Publicly available 
docket materials are available either electronically in regulations.gov 
or in hard copy at the EPA Docket Center, WJC West Building, Room 3334, 
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 EPA Docket Center is 
(202) 566-1742.
    Public Hearing. If requested, we will hold a public hearing 
concerning this proposed rule on July 17, 2014 in the Research Triangle 
Park, North Carolina area. The EPA will provide further information 
about the hearing at the following Web site, http://www.epa.gov/ttn/oarpg/t3main.html, if a hearing is requested. Persons interested in 
presenting oral testimony at the hearing should contact Ms. Virginia 
Hunt, Sector Policies and Programs Division (E143-01), Office of Air 
Quality Planning and Standards, U.S. Environmental Protection Agency, 
Research Triangle Park, NC 27711, telephone number (919) 541-0832, by 
July 17, 2014. If no one requests to speak at the public hearing by 
July 14, 2014, then a public hearing will not be held, and a 
notification of such will be posted on http://www.epa.gov/ttn/oarpg/t3main.html.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Ms. Paula Hirtz, Sector Policies and Programs Division 
(E143-01), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, NC 27711; 
telephone number: (919) 541-2618; fax number: (919) 541-0246; and email 
address: [email protected]. For specific information regarding the 
risk modeling methodology, contact Ms. Darcie Smith, Health and 
Environmental Impacts Division (C504-06), Office of Air Quality 
Planning and

[[Page 37851]]

Standards, U.S. Environmental Protection Agency, Research Triangle 
Park, NC 27711; telephone number (919) 541-2076; fax number: (919) 541-
0840; and email address: [email protected]. For information about 
the applicability of the National Emission Standards for Hazardous Air 
Pollutants (NESHAP) to a particular entity, contact Ms. Marcia Mia, EPA 
Office of Enforcement and Compliance Assurance, telephone number (202) 
564-7042; email address: [email protected].

SUPPLEMENTARY INFORMATION:

Preamble Acronyms and Abbreviations

    We use multiple acronyms and terms in this preamble. While this 
list may not be exhaustive, to ease the reading of this preamble and 
for reference purposes, the EPA defines the following terms and 
acronyms here:

AEGL--acute exposure guideline levels
AERMOD--air dispersion model used by the HEM-3 model
CAA--Clean Air Act
CalEPA--California EPA
CBI--Confidential Business Information
CDX--Central Data Exchange
CEDRI--Compliance and Emissions Data Reporting Interface
CFR--Code of Federal Regulations
EPA--Environmental Protection Agency
ERPG--Emergency Response Planning Guidelines
ERT--Electronic Reporting Tool
FR--Federal Register
HAP--hazardous air pollutants
HCl--hydrochloric acid
HEM-3--Human Exposure Mdel, Version 1.1.0
HF--hydrogen fluoride
HI--hazard index
HON--Hazardous Organic NESHAP
HQ--hazard quotient
ICR--Information Collection Request
IRIS--Integrated Risk Information System
km--kilometer
kPa--kilopascal
LDAR--leak detection and repair
LOAEL--lowest-observed-adverse-effect level
MACT--maximum achievable control technology
m\3\--cubic meter
mg/kg-day--milligrams per kilogram per day
mg/m\3\--milligrams per cubic meter
MIR--maximum individual risk
NAAQS--National Ambient Air Quality Standards
NAICS--North American Industry Classification System
NAS--National Academy of Sciences
NATA--National Air Toxics Assessment
NESHAP--National Emissions Standards for Hazardous Air Pollutants
NOAA--National Oceanic and Atmospheric Organization
NOAEL--no-observed-adverse-effect level
NRC--National Research Council
NTTAA--National Technology Transfer and Advancement Act
OAQPS--Office of Air Quality Planning and Standards
OMB--Office of Management and Budget
OSWRO--off-site waste and recovery operations
PB-HAP--hazardous air pollutants known to be persistent and bio-
accumulative in the environment
PEL--probable effect levels
POM--polycyclic organic matter
ppm--parts per million
PRD-- pressure relief device
PTE--permanent total enclosure
RCO--recuperative thermal oxidizer
RCRA--Resource Conservation and Recovery Act
REL--reference exposure level
RFA--Regulatory Flexibility Act
RfC--reference concentration
RfD--reference dose
RIA--Regulatory Impact Analysis
RTR--residual risk and technology review
SAB--Science Advisory Board
SBA--Small Business Administration
SCC--source classification code
S/L/Ts--State, local and tribal air pollution control agencies
SOP--standard operating procedures
SSM--startup, shutdown and malfunction
TEQ--toxicity equivalence factor
TOC--total organic compound
TOSHI--target organ-specific hazard index
tpy--tons per year
TRIM.FaTE--Total Risk Integrated Methodology.Fate, Transport and 
Ecological Exposure model
TSDF--Solid Waste Treatment, Storage and Disposal Facility
TTN--Technology Transfer Network
UF--uncertainty factor
UMRA--Unfunded Mandates Reform Act
URE--unit risk estimate
VCS--voluntary consensus standards

    Organization of this Document. The information in this preamble is 
organized as follows:

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related 
information?
    C. What should I consider as I prepare my comments for the EPA?
II. Background
    A. What is the statutory authority for this action?
    B. What is this source category and how does the current NESHAP 
regulate its HAP emissions?
    C. What data collection activities were conducted to support 
this action?
III. Analytical Procedures
    A. How did we estimate post-MACT risks posed by the source 
category?
    B. How did we consider the risk results in making decisions for 
this proposal?
    C. How did we perform the technology review?
IV. Analytical Results and Proposed Decisions
    A. What are the results of the risk assessment and analyses?
    B. What are our proposed decisions regarding risk acceptability, 
ample margin of safety and adverse environmental effects?
    C. What are the results of the technology review and our 
proposed decisions?
    D. What other actions are we proposing?
    E. What compliance dates are we proposing?
V. Summary of Cost, Environmental, and Economic Impacts
    A. What are the affected sources?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
VI. Request for Comments
VII. Submitting Data Corrections
VIII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions to Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

A red-line version of the regulatory language that incorporates the 
proposed changes in this action is available in the docket for this 
action (Docket ID No. EPA-HQ-OAR-2012-0360).

I. General Information

A. Does this action apply to me?

    Table 1 of this preamble lists the NESHAP and associated regulated 
industrial source category that is the subject of this proposal. Table 
1 is not intended to be exhaustive but rather to provide a guide for 
readers regarding the entities that this proposed action is likely to 
affect. The proposed standards, once promulgated, will be directly 
applicable to the affected sources. The Off-site Waste and Recovery 
Operations source category was initially titled the ``Solid Waste 
Treatment, Storage, and Disposal Facilities (TSDF)'' source category, 
which included commercial facilities that treat, store or dispose of 
any solid waste received from off-site, as well as commercial 
facilities that recycle, recover and re-refine wastes received from 
off-site.\1\ On October 13,

[[Page 37852]]

1994 (59 FR 51913), the EPA explained that the source category was 
intended to represent those off-site waste and recovery operations that 
are not specifically listed as a separate distinct NESHAP source 
category such as hazardous waste incineration or municipal solid waste 
landfills and changed the title of the Solid Waste TSDF source category 
to ``Off-Site Waste and Recovery Operations'' to avoid confusion, to 
better distinguish this source category from other source categories, 
and to emphasize that this source category addresses only activities 
that manage wastes received from off-site.
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    \1\ See Initial List of Categories of Sources Under Section 
112(c)(1) of the Clean Air Act Amendments of 1990 (57 FR 31576, July 
16, 1992); U.S. EPA. Documentation for Developing the Initial Source 
Category List (EPA-450/3-91-030; July 1992).

                Table 1--NESHAP and Industrial Source Categories Affected By This Proposed Action
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            Source category                        NESHAP                   Examples of regulated entities
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Off-Site Waste and Recovery Operations.  Off-Site Waste and          Businesses or government agencies that
                                          Recovery Operations.        operate any of the following: Hazardous
                                                                      waste TSDF; Resource Conservation and
                                                                      Recovery Act (RCRA) exempt hazardous
                                                                      wastewater treatment facilities;
                                                                      nonhazardous wastewater treatment
                                                                      facilities other than publicly-owned
                                                                      treatment works; used solvent recovery
                                                                      plants; RCRA exempt hazardous waste
                                                                      recycling operations; used oil re-
                                                                      refineries.
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    This table is not intended to be exhaustive, but rather is meant to 
provide a guide for readers regarding entities likely to be affected by 
this action. If you have any questions regarding the applicability of 
this action to a particular entity, consult either the air permitting 
authority for the entity or your EPA regional representative, as listed 
in 40 CFR 63.13 (General Provisions).

B. Where can I get a copy of this document and other related 
information?

    In addition to being available in the docket, an electronic copy of 
this action is available on the Internet through the EPA's Technology 
Transfer Network (TTN) Web site, a forum for information and technology 
exchange in various areas of air pollution control. Following signature 
by the EPA Administrator, the EPA will post a copy of this proposed 
action on the TTN's policy and guidance page for newly proposed or 
promulgated rules at: http://www.epa.gov/ttn/oarpg/t3pfpr.html. 
Following publication in the Federal Register, the EPA will post the 
Federal Register version of the proposal and key technical documents on 
the project Web site: http://www.epa.gov/ttn/atw/offwaste/oswropg.html. 
Information on the overall RTR program is available at the following 
Web site: http://www.epa.gov/ttn/atw/rrisk/rtrpg.html.

C. What should I consider as I prepare my comments for the EPA?

    Submitting CBI. Do not submit information containing CBI to the EPA 
through http://www.regulations.gov or email. Clearly mark the part or 
all of the information that you claim to be CBI. For CBI information on 
a disk or CD-ROM that you mail to the 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 comments that includes information claimed 
as CBI, you must submit a copy of the comments that does not contain 
the information claimed as CBI for inclusion in the public docket. If 
you submit a CD-ROM or disk that does not contain CBI, mark the outside 
of the disk or CD-ROM clearly that it does not contain CBI. Information 
not marked as CBI will be included in the public docket and the EPA's 
electronic public docket without prior notice. Information marked as 
CBI will not be disclosed except in accordance with procedures set 
forth in 40 Code of Federal Regulations (CFR) part 2. Send or deliver 
information identified as CBI only to the following address: Roberto 
Morales, OAQPS Document Control Officer (C404-02), OAQPS, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711, Attention Docket ID No. EPA-HQ-OAR-2012-0360.

II. Background

A. What is the statutory authority for this action?

    Section 112 of the CAA establishes a two-stage regulatory process 
to address emissions of hazardous air pollutants (HAPs) from stationary 
sources. In the first stage, after the EPA has identified categories of 
sources emitting one or more of the HAP listed in CAA section 112(b), 
CAA section 112(d) requires us to promulgate technology-based NESHAP 
for those sources. ``Major sources'' are those that emit or have the 
potential to emit 10 tons per year (tpy) or more of a single HAP or 25 
tpy or more of any combination of HAPs. For major sources, the 
technology-based NESHAP must reflect the maximum degree of emission 
reductions of HAPs achievable (after considering cost, energy 
requirements and non-air quality health and environmental impacts) and 
are commonly referred to as maximum achievable control technology 
(MACT) standards.
    MACT standards must reflect the maximum degree of emissions 
reduction achievable through the application of measures, processes, 
methods, systems or techniques, including, but not limited to, measures 
that (1) reduce the volume of or eliminate pollutants through process 
changes, substitution of materials or other modifications; (2) enclose 
systems or processes to eliminate emissions; (3) capture or treat 
pollutants when released from a process, stack, storage or fugitive 
emissions point; (4) are design, equipment, work practice or 
operational standards (including requirements for operator training or 
certification); or (5) are a combination of the above. CAA section 
112(d)(2)(A)-(E). The MACT standards may take the form of design, 
equipment, work practice or operational standards where the EPA first 
determines either that (1) a pollutant cannot be emitted through a 
conveyance designed and constructed to emit or capture the pollutant, 
or that any requirement for, or use of, such a conveyance would be 
inconsistent with law; or (2) the application of measurement 
methodology to a particular class of sources is not practicable due to 
technological and economic limitations. CAA section 112(h)(1)-(2).
    The MACT ``floor'' is the minimum control level allowed for MACT 
standards promulgated under CAA section 112(d)(3) and may not be based 
on cost considerations. For new sources, the MACT floor cannot be less 
stringent than the emissions control that is achieved in practice by 
the best-

[[Page 37853]]

controlled similar source. The MACT floor for existing sources can be 
less stringent than floors for new sources but not less stringent than 
the average emissions limitation achieved by the best-performing 12 
percent of existing sources in the category or subcategory (or the 
best-performing five sources for categories or subcategories with fewer 
than 30 sources). In developing MACT standards, the EPA must also 
consider control options that are more stringent than the floor. We may 
establish standards more stringent than the floor based on 
considerations of the cost of achieving the emission reductions, any 
non-air quality health and environmental impacts and energy 
requirements.
    The EPA is required to review these technology-based standards and 
revise them ``as necessary (taking into account developments in 
practices, processes, and control technologies)'' no less frequently 
than every eight years. CAA section 112(d)(6). In conducting this 
review, the EPA is not required to recalculate the MACT floor. Natural 
Resources Defense Council (NRDC) v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 
2008). Association of Battery Recyclers, Inc. v. EPA, 716 F.3d 667 
(D.C. Cir. 2013).
    The second stage in standard-setting focuses on reducing any 
remaining (i.e., ``residual'') risk according to CAA section 112(f). 
Section 112(f)(1) required EPA to prepare a report to Congress 
discussing (among other things) methods of calculating the risks posed 
(or potentially posed) by sources after implementation of the MACT 
standards, the public health significance of those risks and the EPA's 
recommendations as to legislation regarding such remaining risk. The 
EPA prepared and submitted the Residual Risk Report to Congress, EPA-
453/R-99-001 (Risk Report) in March 1999. Section 112(f)(2) then 
provides that if Congress does not act on any recommendation in the 
Report, EPA must analyze and address residual risk for each category or 
subcategory of sources within 8 years after promulgation of such 
standards pursuant to section 112(d).
    Section 112(f)(2) of the CAA requires the EPA to determine for 
source categories subject to MACT standards whether the emission 
standards provide an ample margin of safety to protect public health. 
Section 112(f)(2)(B) of the CAA expressly preserves the EPA's use of 
the two-step process for developing standards to address any residual 
risk and the agency's interpretation of ``ample margin of safety'' 
developed in the National Emissions Standards for Hazardous Air 
Pollutants: Benzene Emissions from Maleic Anhydride Plants, 
Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment 
Leaks, and Coke By-Product Recovery Plants (Benzene NESHAP) (54 FR 
38044, September 14, 1989). The EPA notified Congress in the Risk 
Report that the agency intended to use the Benzene NESHAP approach in 
making CAA section 112(f) residual risk determinations (EPA-453/R-99-
001, p. ES-11). The EPA subsequently adopted this approach in its 
residual risk determinations and in a challenge to the risk review for 
the Synthetic Organic Chemical Manufacturing source category, the 
United States Court of Appeals for the District of Columbia Circuit 
upheld as reasonable the EPA's interpretation that subsection 112(f)(2) 
incorporates the approach established in the Benzene NESHAP. See NRDC 
v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008)(``[S]ubsection 
112(f)(2)(B) expressly incorporates the EPA's interpretation of the 
Clean Air Act from the Benzene standard, complete with a citation to 
the Federal Register.''); see also A Legislative History of the Clean 
Air Act Amendments of 1990, vol. 1, p. 877 (Senate debate on Conference 
Report).
    The first step in the process of evaluating residual risk is the 
determination of acceptable risk. If risks are unacceptable, the EPA 
cannot consider cost in identifying the emissions standards necessary 
to bring risks to an acceptable level. The second step is the 
determination of whether standards must be further revised in order to 
provide an ample margin of safety to protect public health. The ample 
margin of safety is the level at which the standards must be set, 
unless an even more stringent standard is necessary to prevent, taking 
into consideration costs, energy, safety and other relevant factors, an 
adverse environmental effect.
1. Step 1--Determination of Acceptability
    The agency in the Benzene NESHAP concluded that ``the acceptability 
of risk under section 112 is best judged on the basis of a broad set of 
health risk measures and information'' and that the ``judgment on 
acceptability cannot be reduced to any single factor.'' Benzene NESHAP 
at 38046. The determination of what represents an ``acceptable'' risk 
is based on a judgment of ``what risks are acceptable in the world in 
which we live'' (Risk Report at 178, quoting NRDC v. EPA, 824 F. 2d 
1146, 1165 (D.C. Cir. 1987) (en banc) (``Vinyl Chloride''), recognizing 
that our world is not risk-free.
    In the Benzene NESHAP, we stated that ``EPA will generally presume 
that if the risk to [the maximum exposed] individual is no higher than 
approximately one in 10 thousand, that risk level is considered 
acceptable.'' 54 FR at 38045, September 14, 1989. We discussed the 
maximum individual lifetime cancer risk (or maximum individual risk 
(MIR)) as being ``the estimated risk that a person living near a plant 
would have if he or she were exposed to the maximum pollutant 
concentrations for 70 years.'' Id. We explained that this measure of 
risk ``is an estimate of the upper bound of risk based on conservative 
assumptions, such as continuous exposure for 24 hours per day for 70 
years.'' Id. We acknowledged that maximum individual lifetime cancer 
risk ``does not necessarily reflect the true risk, but displays a 
conservative risk level which is an upper-bound that is unlikely to be 
exceeded.'' Id.
    Understanding that there are both benefits and limitations to using 
the MIR as a metric for determining acceptability, we acknowledged in 
the Benzene NESHAP that ``consideration of maximum individual risk * * 
* must take into account the strengths and weaknesses of this measure 
of risk.'' Id. Consequently, the presumptive risk level of 100-in-1 
million (1-in-10 thousand) provides a benchmark for judging the 
acceptability of maximum individual lifetime cancer risk, but does not 
constitute a rigid line for making that determination. Further, in the 
Benzene NESHAP, we noted that:

[p]articular attention will also be accorded to the weight of 
evidence presented in the risk assessment of potential 
carcinogenicity or other health effects of a pollutant. While the 
same numerical risk may be estimated for an exposure to a pollutant 
judged to be a known human carcinogen, and to a pollutant considered 
a possible human carcinogen based on limited animal test data, the 
same weight cannot be accorded to both estimates. In considering the 
potential public health effects of the two pollutants, the Agency's 
judgment on acceptability, including the MIR, will be influenced by 
the greater weight of evidence for the known human carcinogen.

Id. at 38046. The agency also explained in the Benzene NESHAP that:

[i]n establishing a presumption for MIR, rather than a rigid line 
for acceptability, the Agency intends to weigh it with a series of 
other health measures and factors. These include the overall 
incidence of cancer or other serious health effects within the 
exposed population, the numbers of persons exposed within each 
individual lifetime risk range and associated incidence within, 
typically, a 50 km exposure radius around facilities, the science 
policy assumptions and

[[Page 37854]]

estimation uncertainties associated with the risk measures, weight 
of the scientific evidence for human health effects, other 
quantified or unquantified health effects, effects due to co-
location of facilities, and co-emission of pollutants.

Id. At 38045. In some cases, these health measures and factors taken 
together may provide a more realistic description of the magnitude of 
risk in the exposed population than that provided by maximum individual 
lifetime cancer risk alone.
    As noted earlier, in NRDC v. EPA, the court held that section 
112(f)(2) ``incorporates the EPA's interpretation of the Clean Air Act 
from the Benzene Standard.'' The court further held that Congress' 
incorporation of the Benzene standard applies equally to carcinogens 
and non-carcinogens. 529 F.3d at 1081-82. Accordingly, we also consider 
non-cancer risk metrics in our determination of risk acceptability and 
ample margin of safety.
2. Step 2--Determination of Ample Margin of Safety
    CAA section 112(f)(2) requires the EPA to determine, for source 
categories subject to MACT standards, whether those standards provide 
an ample margin of safety to protect public health. As explained in the 
Benzene NESHAP, ``the second step of the inquiry, determining an `ample 
margin of safety,' again includes consideration of all of the health 
factors, and whether to reduce the risks even further . . . . Beyond 
that information, additional factors relating to the appropriate level 
of control will also be considered, including costs and economic 
impacts of controls, technological feasibility, uncertainties and any 
other relevant factors. Considering all of these factors, the agency 
will establish the standard at a level that provides an ample margin of 
safety to protect the public health, as required by section 112.'' 54 
FR at 38046, September 14, 1989.
    According to CAA section 112(f)(2)(A), if the MACT standards for 
HAP ``classified as a known, probable, or possible human carcinogen do 
not reduce lifetime excess cancer risks to the individual most exposed 
to emissions from a source in the category or subcategory to less than 
one in one million,'' the EPA must promulgate residual risk standards 
for the source category (or subcategory), as necessary to provide an 
ample margin of safety to protect public health. In doing so, the EPA 
may adopt standards equal to existing MACT standards if the EPA 
determines that the existing standards (i.e., the MACT standards) are 
sufficiently protective. NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 
2008) (``If EPA determines that the existing technology-based standards 
provide an `ample margin of safety,' then the Agency is free to readopt 
those standards during the residual risk rulemaking.'') The EPA must 
also adopt more stringent standards, if necessary, to prevent an 
adverse environmental effect,\2\ but must consider cost, energy, safety 
and other relevant factors in doing so.
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    \2\ ``Adverse environmental effect'' is defined as any 
significant and widespread adverse effect, which may be reasonably 
anticipated to wildlife, aquatic life or natural resources, 
including adverse impacts on populations of endangered or threatened 
species or significant degradation of environmental qualities over 
broad areas. CAA section 112(a)(7).
---------------------------------------------------------------------------

    The CAA does not specifically define the terms ``individual most 
exposed,'' ``acceptable level'' and ``ample margin of safety.'' In the 
Benzene NESHAP, 54 FR at 38044-38045, September 14, 1989, we stated as 
an overall objective:

    In protecting public health with an ample margin of safety under 
section 112, EPA strives to provide maximum feasible protection 
against risks to health from hazardous air pollutants by (1) 
protecting the greatest number of persons possible to an individual 
lifetime risk level no higher than approximately 1-in-1 million and 
(2) limiting to no higher than approximately 1-in-10 thousand [i.e., 
100-in-1 million] the estimated risk that a person living near a 
plant would have if he or she were exposed to the maximum pollutant 
concentrations for 70 years.

The agency further stated that ``[t]he EPA also considers incidence 
(the number of persons estimated to suffer cancer or other serious 
health effects as a result of exposure to a pollutant) to be an 
important measure of the health risk to the exposed population. 
Incidence measures the extent of health risks to the exposed population 
as a whole, by providing an estimate of the occurrence of cancer or 
other serious health effects in the exposed population.'' Id. at 38045.
    In the ample margin of safety decision process, the agency again 
considers all of the health risks and other health information 
considered in the first step, including the incremental risk reduction 
associated with standards more stringent than the MACT standard or a 
more stringent standard that the EPA has determined is necessary to 
ensure risk is acceptable. In the ample margin of safety analysis, the 
agency considers additional factors, including costs and economic 
impacts of controls, technological feasibility, uncertainties and any 
other relevant factors. Considering all of these factors, the agency 
will establish the standard at a level that provides an ample margin of 
safety to protect the public health, as required by CAA section 112(f). 
54 FR 38046, September 14, 1989.

B. What is this source category and how does the current NESHAP 
regulate its HAP emissions?

    The NESHAP for OSWRO was proposed on October 13, 1994 (59 FR 
51913), promulgated on July 1, 1996 (61 FR 34140), and codified at 40 
CFR part 63, subpart DD. The final rule was amended on July 20, 1999 
(64 FR 38950). In general, the rule applies to waste management units 
and recovery operations that are: (1) Located at major sources of HAP 
emissions; and (2) used to manage, convey or handle used oil, used 
solvent or waste received from other facilities and that contain at 
least one of 97 organic HAP specified in the rule.\3\ The HAP emission 
sources at facilities subject to the OSWRO NESHAP are tanks, 
containers, surface impoundments, oil-water separators, organic-water 
separators, process vents and transfer systems used to manage off-site 
material and equipment leaks. The MACT standards regulate these 
emissions sources through emission limits, equipment standards and work 
practices.
---------------------------------------------------------------------------

    \3\ The OSWRO MACT rule defines ``waste,'' ``used oil'' and 
``used solvent'' in 40 CFR 63.681 Definitions.
---------------------------------------------------------------------------

C. What data collection activities were conducted to support this 
action?

    Under the authority of CAA section 114, we sent questionnaires to 
nine companies that own and operate OSWRO facilities. In the CAA 
section 114 questionnaires, we asked for information about process 
equipment, control devices, work practices, associated emission 
reductions, point and fugitive emissions, and other aspects of facility 
operations. We visited three facilities, and reviewed permit data from 
18 state and local agencies. In addition, we reviewed several EPA 
databases to identify facilities that may be part of the source 
category. We also reviewed data in the EPA's National Emissions 
Inventory (NEI) to identify emission sources and quantities of 
emissions and the Toxics Release Inventory (TRI) to verify emissions 
estimates.
    The data gathered through these activities are described further in 
the memorandum Development of the RTR Emissions Dataset for the Off-
Site Waste and Recovery Operations Source Category, which is available 
in the docket for this proposed rule.

[[Page 37855]]

III. Analytical Procedures

    In this section, we describe the analyses performed to support the 
proposed decisions for the RTR and other issues addressed in this 
proposal.

A. How did we estimate post-MACT risks posed by the source category?

    The EPA conducted a risk assessment that provides estimates of the 
MIR posed by the HAP emissions from each source in the source category, 
the hazard index (HI) for chronic exposures to HAP with the potential 
to cause non-cancer health effects, and the hazard quotient (HQ) for 
acute exposures to HAP with the potential to cause non-cancer health 
effects. The assessment also provides estimates of the distribution of 
cancer risks within the exposed populations, cancer incidence and an 
evaluation of the potential for adverse environmental effects for the 
source category. The eight sections that follow this paragraph describe 
how we estimated emissions and conducted the risk assessment. The 
docket for this proposed rule contains the following document which 
provides more information on the risk assessment inputs and models: 
Draft Residual Risk Assessment for the Off-Site Waste and Recovery 
Operations Source Category. The methods used to assess risks (as 
described in the eight primary steps below) are consistent with those 
peer-reviewed by a panel of the EPA's Science Advisory Board (SAB) in 
2009 and described in their peer review report issued in 2010 \4\; they 
are also consistent with the key recommendations contained in that 
report.
---------------------------------------------------------------------------

    \4\ U.S. EPA SAB. Risk and Technology Review (RTR) Risk 
Assessment Methodologies: For Review by the EPA's Science Advisory 
Board with Case Studies--MACT I Petroleum Refining Sources and 
Portland Cement Manufacturing, May 2010.
---------------------------------------------------------------------------

1. How did we estimate actual emissions and identify the emissions 
release characteristics?
    Data for 38 OSWRO facilities were used to create an RTR emissions 
dataset (i.e., risk model input file). This RTR emissions dataset is 
based on a combination of data gathered through the CAA section 114 
questionnaire and the 2005 NEI. The NEI is a database that contains 
information about sources that emit criteria air pollutants, their 
precursors and HAP. The database includes estimates of annual air 
pollutant emissions from point, nonpoint and mobile sources in the 50 
states, the District of Columbia, Puerto Rico and the Virgin Islands. 
The EPA collects this information and releases an updated version of 
the NEI database every 3 years. The NEI includes information necessary 
for conducting risk modeling, including annual HAP emissions estimates 
from individual emission points at facilities and the related emissions 
release parameters. Other databases, including the TRI and Envirofacts, 
were consulted to verify emissions estimates and to identify facilities 
that are part of the OSWRO source category. As part of our quality 
assurance review, we reviewed the emissions data and release 
characteristics data in the RTR emissions dataset to ensure the data 
were accurate. We also checked the coordinates of each emission source 
in the dataset using tools such as Google Earth and ArcView to ensure 
the emission point locations were correct.
    While data for 38 OSWRO facilities were included in the RTR 
emissions dataset, available data indicate there are 52 currently 
operating major source facilities that are subject to the OSWRO MACT 
standards. The remaining 14 facilities were not included in the 
modeling file because the information available to the EPA, including 
the NEI, did not attribute any amount of HAP emissions to off-site 
waste and recovery operations at these facilities. It was also not 
possible to discern from the emission point identifiers or 
characteristics in the inventory which emissions could be attributed to 
the OSWRO source category. We note that available permit information 
indicates that five of these 14 facilities are only subject to off-site 
waste HAP content determination requirements and are not subject to the 
emissions standards and other requirements of the OSWRO NESHAP due to 
the low amount of HAP in the off-site waste accepted by these 
facilities. Also, available permit data indicates that two additional 
facilities are not subject to the emissions standards and other 
requirements of the OSWRO NESHAP because they comply instead with 40 
CFR part 61, subpart FF, as allowed by the OSWRO NESHAP. For these 
seven facilities, we would not expect any emission points to be labeled 
as OSWRO emission points in the NEI because those emission points are 
not subject to any OSWRO MACT emissions standards. We also did not 
collect data from these facilities through our CAA section 114 
questionnaire. As noted in section VI of this preamble, we are 
requesting site-specific emissions data that would enable us to better 
characterize the maximum risks from the OSWRO source category. A list 
of the 52 facilities and additional information about the development 
of the RTR emissions dataset is provided in the technical document: 
Development of the RTR Emissions Dataset for the Off-Site Waste and 
Recovery Operations Source Category, which is available in the docket 
for this action.
2. How did we estimate MACT-allowable emissions?
    The available emissions data in the RTR emissions dataset include 
estimates of the mass of HAP emitted during the specified annual time 
period. In some cases, these ``actual'' emission levels are lower than 
the emission levels required to comply with the MACT standards. The 
emissions level allowed to be emitted by the MACT standards is referred 
to as the ``MACT-allowable'' emissions level. We discussed the use of 
both MACT-allowable and actual emissions in the final Coke Oven 
Batteries residual risk rule (70 FR 19998-19999, April 15, 2005) and in 
the proposed and final Hazardous Organic NESHAP residual risk rules (71 
FR 34428, June 14, 2006, and 71 FR 76609, December 21, 2006, 
respectively). In those previous actions, we noted that assessing the 
risks at the MACT-allowable level is inherently reasonable since these 
risks reflect the maximum level facilities could emit and still comply 
with national emission standards. We also explained that it is 
reasonable to consider actual emissions, where such data are available, 
in both steps of the risk analysis, in accordance with the Benzene 
NESHAP approach. (54 FR 38044, September 14, 1989.)
    We used the emissions data gathered from the 2005 NEI and responses 
to the CAA section 114 questionnaire to estimate the MACT-allowable 
emissions levels. We estimate that the actual emissions level is 
representative of the MACT-allowable level for all emissions sources 
except tanks and process vents. Based on responses to the CAA section 
114 questionnaire, we estimate that MACT-allowable emissions from tanks 
and process vents could be up to five times the actual emissions. For 
some facilities, we cannot assign HAP emissions to a specific type of 
emission source (e.g., a process vent) due to a lack of specificity in 
the emission point identifiers in the NEI. For facilities where we 
could identify specific emission source types, we applied a factor of 5 
to the actual emissions attributable to tanks and process vents. A 
factor of 1 was applied to the actual emissions for other emissions 
sources (e.g., equipment leaks). For facilities where we could not 
identify specific emission source types, we developed and applied a 
factor of 2.5 to all the OSWRO emissions. The 2.5 factor is

[[Page 37856]]

based on the factor of 5 for tanks and process vents and information 
from the responses to the CAA section 114 questionnaire indicating that 
tank and process vent emissions comprise approximately half of the 
total OSWRO emissions.
    For more detail about this estimate of the MACT-allowable 
emissions, see the memorandum, MACT-Allowable Emissions for the Off-
Site Waste and Recovery Operations Source Category, which is available 
in the docket for this action.
3. How did we conduct dispersion modeling, determine inhalation 
exposures and estimate individual and population inhalation risks?
    Both long-term and short-term inhalation exposure concentrations 
and health risks from the source category addressed in this proposal 
were estimated using the Human Exposure Model (Community and Sector 
HEM-3 version 1.1.0). The HEM-3 performs three primary risk assessment 
activities: (1) Conducting dispersion modeling to estimate the 
concentrations of HAP in ambient air, (2) estimating long-term and 
short-term inhalation exposures to individuals residing within 50 
kilometers (km) of the modeled sources \5\, and (3) estimating 
individual and population-level inhalation risks using the exposure 
estimates and quantitative dose-response information.
---------------------------------------------------------------------------

    \5\ This metric comes from the Benzene NESHAP. See 54 FR 38046.
---------------------------------------------------------------------------

    The air dispersion model used by the HEM-3 model (AERMOD) is one of 
the EPA's preferred models for assessing pollutant concentrations from 
industrial facilities.\6\ To perform the dispersion modeling and to 
develop the preliminary risk estimates, HEM-3 draws on three data 
libraries. The first is a library of meteorological data, which is used 
for dispersion calculations. This library includes 1 year (2011) of 
hourly surface and upper air observations for more than 800 
meteorological stations, selected to provide coverage of the United 
States and Puerto Rico. A second library of United States Census Bureau 
census block \7\ internal point locations and populations provides the 
basis of human exposure calculations (U.S. Census, 2010). In addition, 
for each census block, the census library includes the elevation and 
controlling hill height, which are also used in dispersion 
calculations. A third library of pollutant unit risk factors and other 
health benchmarks is used to estimate health risks. These risk factors 
and health benchmarks are the latest values recommended by the EPA for 
HAP and other toxic air pollutants. These values are available at: 
http://www.epa.gov/ttn/atw/toxsource/summary.html and are discussed in 
more detail later in this section.
---------------------------------------------------------------------------

    \6\ U.S. EPA. Revision to the Guideline on Air Quality Models: 
Adoption of a Preferred General Purpose (Flat and Complex Terrain) 
Dispersion Model and Other Revisions (70 FR 68218, November 9, 
2005).
    \7\ A census block is the smallest geographic area for which 
census statistics are tabulated.
---------------------------------------------------------------------------

    In developing the risk assessment for chronic exposures, we used 
the estimated annual average ambient air concentrations of each HAP 
emitted by each source for which we have emissions data in the source 
category. The air concentrations at each nearby census block centroid 
were used as a surrogate for the chronic inhalation exposure 
concentration for all the people who reside in that census block. We 
calculated the MIR for each facility as the cancer risk associated with 
a continuous lifetime (24 hours per day, 7 days per week, and 52 weeks 
per year for a 70-year period) exposure to the maximum concentration at 
the centroid of inhabited census blocks. Individual cancer risks were 
calculated by multiplying the estimated lifetime exposure to the 
ambient concentration of each of the HAP (in micrograms per cubic meter 
([mu]g/m\3\)) by its unit risk estimate (URE). The URE is an upper 
bound estimate of an individual's probability of contracting cancer 
over a lifetime of exposure to a concentration of 1 microgram of the 
pollutant per cubic meter of air. For residual risk assessments, we 
generally use URE values from the EPA's Integrated Risk Information 
System (IRIS). For carcinogenic pollutants without EPA IRIS values, we 
look to other reputable sources of cancer dose-response values, often 
using California EPA (CalEPA) URE values, where available. In cases 
where new, scientifically credible dose response values have been 
developed in a manner consistent with the EPA guidelines and have 
undergone a peer review process similar to that used by the EPA, we may 
use such dose-response values in place of, or in addition to, other 
values, if appropriate.
    The EPA estimated incremental individual lifetime cancer risks 
associated with emissions from the facilities in the source category as 
the sum of the risks for each of the carcinogenic HAP (including those 
classified as carcinogenic to humans, likely to be carcinogenic to 
humans, and suggestive evidence of carcinogenic potential \8\) emitted 
by the modeled sources. Cancer incidence and the distribution of 
individual cancer risks for the population within 50 km of the sources 
were also estimated for the source category as part of this assessment 
by summing individual risks. A distance of 50 km is consistent with 
both the analysis supporting the 1989 Benzene NESHAP (54 FR 38044, 
September 14, 1989) and the limitations of Gaussian dispersion models, 
including AERMOD.
---------------------------------------------------------------------------

    \8\ These classifications also coincide with the terms ``known 
carcinogen, probable carcinogen, and possible carcinogen,'' 
respectively, which are the terms advocated in the EPA's previous 
Guidelines for Carcinogen Risk Assessment, published in 1986 (51 FR 
33992, September 24, 1986). Summing the risks of these individual 
compounds to obtain the cumulative cancer risks is an approach that 
was recommended by the EPA's Science Advisory Board (SAB) in their 
2002 peer review of EPA's National Air Toxics Assessment (NATA) 
entitled, NATA--Evaluating the National-scale Air Toxics Assessment 
1996 Data--an SAB Advisory, available at: http://yosemite.epa.gov/
sab/sabproduct.nsf/214C6E915BB04E14852570CA007A682C/$File/
ecadv02001.pdf.
---------------------------------------------------------------------------

    To assess the risk of non-cancer health effects from chronic 
exposures, we summed the HQ for each of the HAP that affects a common 
target organ system to obtain the HI for that target organ system (or 
target organ-specific HI, TOSHI). The HQ is the estimated exposure 
divided by the chronic reference value, which is a value selected from 
one of several sources. First, the chronic reference level can be the 
EPA reference concentration (RfC), (http://www.epa.gov/riskassessment/glossary.htm), defined as ``an estimate (with uncertainty spanning 
perhaps an order of magnitude) of a continuous inhalation exposure to 
the human population (including sensitive subgroups) that is likely to 
be without an appreciable risk of deleterious effects during a 
lifetime.'' Alternatively, in cases where an RfC from the EPA's IRIS 
database is not available, or where the EPA determines that using a 
value other than the RfC is appropriate, the chronic reference level 
can be a value from the following prioritized sources: (1) The Agency 
for Toxic Substances and Disease Registry Minimum Risk Level (http://www.atsdr.cdc.gov/mrls/index.asp), which is defined as ``an estimate of 
daily human exposure to a hazardous substance that is likely to be 
without an appreciable risk of adverse non-cancer health effects (other 
than cancer) over a specified duration of exposure''; (2) the CalEPA 
Chronic Reference Exposure Level (REL) (http://www.oehha.ca.gov/air/hot_spots/pdf/HRAguidefinal.pdf), which is defined as ``the 
concentration level (that is expressed in units of micrograms per

[[Page 37857]]

cubic meter ([mu]g/m3) for inhalation exposure and in a dose expressed 
in units of milligram per kilogram-day (mg/kg-day) for oral exposures), 
at or below which no adverse health effects are anticipated for a 
specified exposure duration''; or (3) as noted above, a scientifically 
credible dose-response value that has been developed in a manner 
consistent with the EPA guidelines and has undergone a peer review 
process similar to that used by the EPA, in place of or in concert with 
other values.
    The EPA also evaluated screening estimates of acute exposures and 
risks for each of the HAP at the point of highest off-site exposure for 
each facility (i.e., not just the census block centroids), assuming 
that a person is located at this spot at a time when both the peak 
(hourly) emissions rate and worst-case dispersion conditions occur. The 
acute HQ is the estimated acute exposure divided by the acute dose-
response value. In each case, the EPA calculated acute HQ values using 
best available, short-term dose-response values. These acute dose-
response values, which are described below, include the acute REL, 
acute exposure guideline levels (AEGL) and emergency response planning 
guidelines (ERPG) for 1-hour exposure durations. As discussed below, we 
used conservative assumptions for emissions rates, meteorology and 
exposure location for our acute analysis.
    As described in the CalEPA's Air Toxics Hot Spots Program Risk 
Assessment Guidelines, Part I, The Determination of Acute Reference 
Exposure Levels for Airborne Toxicants, an acute REL value (http://www.oehha.ca.gov/air/pdf/acuterel.pdf) is defined as, ``the 
concentration level at or below which no adverse health effects are 
anticipated for a specified exposure duration.'' Id. at page 2. Acute 
REL values are based on the most sensitive, relevant, adverse health 
effect reported in the peer-reviewed medical and toxicological 
literature. Acute REL values are designed to protect the most sensitive 
individuals in the population through the inclusion of margins of 
safety. Because margins of safety are incorporated to address data gaps 
and uncertainties, exceeding the REL does not automatically indicate an 
adverse health impact.
    AEGL values were derived in response to recommendations from the 
National Research Council (NRC). As described in Standing Operating 
Procedures (SOP) of the National Advisory Committee on Acute Exposure 
Guideline Levels for Hazardous Substances (http://www.epa.gov/oppt/aegl/pubs/sop.pdf),\9\ ``the NRC's previous name for acute exposure 
levels--community emergency exposure levels--was replaced by the term 
AEGL to reflect the broad application of these values to planning, 
response, and prevention in the community, the workplace, 
transportation, the military, and the remediation of Superfund sites.'' 
Id. at 2. This document also states that AEGL values ``represent 
threshold exposure limits for the general public and are applicable to 
emergency exposures ranging from 10 minutes to eight hours.'' Id. at 2.
---------------------------------------------------------------------------

    \9\ National Academy of Sciences (NAS), 2001. Standing Operating 
Procedures for Developing Acute Exposure Levels for Hazardous 
Chemicals, page 2.
---------------------------------------------------------------------------

    The document lays out the purpose and objectives of AEGL by stating 
that ``the primary purpose of the AEGL program and the National 
Advisory Committee for Acute Exposure Guideline Levels for Hazardous 
Substances is to develop guideline levels for once-in-a-lifetime, 
short-term exposures to airborne concentrations of acutely toxic, high-
priority chemicals.'' Id. at 21. In detailing the intended application 
of AEGL values, the document states that ``[i]t is anticipated that the 
AEGL values will be used for regulatory and non-regulatory purposes by 
U.S. Federal and state agencies and possibly the international 
community in conjunction with chemical emergency response, planning, 
and prevention programs. More specifically, the AEGL values will be 
used for conducting various risk assessments to aid in the development 
of emergency preparedness and prevention plans, as well as real-time 
emergency response actions, for accidental chemical releases at fixed 
facilities and from transport carriers.'' Id. at 31.
    The AEGL-1 value is then specifically defined as ``the airborne 
concentration (expressed as ppm (parts per million) or mg/m3 
(milligrams per cubic meter)) of a substance above which it is 
predicted that the general population, including susceptible 
individuals, could experience notable discomfort, irritation, or 
certain asymptomatic non-sensory effects. However, the effects are not 
disabling and are transient and reversible upon cessation of 
exposure.'' Id. at 3. The document also notes that, ``Airborne 
concentrations below AEGL-1 represent exposure levels that can produce 
mild and progressively increasing but transient and non-disabling odor, 
taste, and sensory irritation or certain asymptomatic, non-sensory 
effects.'' Id. Similarly, the document defines AEGL-2 values as ``the 
airborne concentration (expressed as parts per million or milligrams 
per cubic meter) 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.'' Id.
    ERPG values are derived for use in emergency response, as described 
in the American Industrial Hygiene Association's ERP Committee document 
entitled, ERPGS Procedures and Responsibilities (http://sp4m.aiha.org/insideaiha/GuidelineDevelopment/ERPG/Documents/ERP-SOPs2006.pdf), which 
states that, ``Emergency Response Planning Guidelines were developed 
for emergency planning and are intended as health based guideline 
concentrations for single exposures to chemicals.'' \10\ Id. at 1. The 
ERPG-1 value is defined as ``the maximum airborne concentration below 
which it is believed that nearly all individuals could be exposed for 
up to 1 hour without experiencing other than mild transient adverse 
health effects or without perceiving a clearly defined, objectionable 
odor.'' Id. at 2. Similarly, the ERPG-2 value is defined as ``the 
maximum airborne concentration below which it is believed that nearly 
all individuals could be exposed for up to one hour without 
experiencing or developing irreversible or other serious health effects 
or symptoms which could impair an individual's ability to take 
protective action.'' Id. at 1.
---------------------------------------------------------------------------

    \10\ ERP Committee Procedures and Responsibilities. November 1, 
2006. American Industrial Hygiene Association.
---------------------------------------------------------------------------

    As can be seen from the definitions above, the AEGL and ERPG values 
include the similarly-defined severity levels 1 and 2. For many 
chemicals, a severity level 1 value AEGL or ERPG has not been developed 
because the types of effects for these chemicals are not consistent 
with the AEGL-1/ERPG-1 definitions; in these instances, we compare 
higher severity level AEGL-2 or ERPG-2 values to our modeled exposure 
levels to screen for potential acute concerns. When AEGL-1/ERPG-1 
values are available, they are used in our acute risk assessments.
    Acute REL values for 1-hour exposure durations are typically lower 
than their corresponding AEGL-1 and ERPG-1 values. Even though their 
definitions are slightly different, AEGL-1 values are often the same as 
the corresponding ERPG-1 values, and AEGL-2 values are often equal to 
ERPG-2 values. Maximum HQ values from our acute screening risk 
assessments typically

[[Page 37858]]

result when basing them on the acute REL value for a particular 
pollutant. In cases where our maximum acute HQ value exceeds 1, we also 
report the HQ value based on the next highest acute dose-response value 
(usually the AEGL-1 and/or the ERPG-1 value).
    To develop screening estimates of acute exposures in the absence of 
hourly emissions data, generally we first develop estimates of maximum 
hourly emissions rates by multiplying the average actual annual hourly 
emissions rates by a default factor to cover routinely variable 
emissions. We choose the factor to use partially based on process 
knowledge and engineering judgment. The factor chosen also reflects a 
Texas study of short-term emissions variability, which showed that most 
peak emission events in a heavily-industrialized four-county area 
(Harris, Galveston, Chambers and Brazoria Counties, Texas) were less 
than twice the annual average hourly emissions rate. The highest peak 
emissions event was 74 times the annual average hourly emissions rate, 
and the 99th percentile ratio of peak hourly emissions rate to the 
annual average hourly emissions rate was 9.\11\ Considering this 
analysis, to account for more than 99 percent of the peak hourly 
emissions, we apply a conservative screening multiplication factor of 
10 to the average annual hourly emissions rate in our acute exposure 
screening assessments as our default approach. However, we use a factor 
other than 10 if we have information that indicates that a different 
factor is appropriate for a particular source category. For this source 
category, there was no such information available and the default 
factor of 10 was used in the acute screening process.
---------------------------------------------------------------------------

    \11\ See http://www.tceq.state.tx.us/compliance/field_ops/eer/index.html or docket to access the source of these data.
---------------------------------------------------------------------------

    As part of our acute risk assessment process, for cases where acute 
HQ values from the screening step were less than or equal to 1 (even 
under the conservative assumptions of the screening analysis), acute 
impacts were deemed negligible and no further analysis was performed. 
In cases where an acute HQ from the screening step was greater than 1, 
additional site-specific data were considered to develop a more refined 
estimate of the potential for acute impacts of concern. For this source 
category, there were no offsite acute values greater than 1, and no 
refined estimates were developed. Ideally, we would prefer to have 
continuous measurements over time to see how the emissions vary by each 
hour over an entire year. Having a frequency distribution of hourly 
emissions rates over a year would allow us to perform a probabilistic 
analysis to estimate potential threshold exceedances and their 
frequency of occurrence. Such an evaluation could include a more 
complete statistical treatment of the key parameters and elements 
adopted in this screening analysis. Recognizing that this level of data 
is rarely available, we instead rely on the multiplier approach.
    To better characterize the potential health risks associated with 
estimated acute exposures to HAP, and in response to a key 
recommendation from the SAB's peer review of the EPA's RTR risk 
assessment methodologies,\12\ we generally examine a wider range of 
available acute health metrics (e.g., RELs, AEGLs) than we do for our 
chronic risk assessments. This is in response to the SAB's 
acknowledgement that there are generally more data gaps and 
inconsistencies in acute reference values than there are in chronic 
reference values. In some cases, when Reference Value Arrays \13\ for 
HAP have been developed, we consider additional acute values (i.e., 
occupational and international values) to provide a more complete risk 
characterization.
---------------------------------------------------------------------------

    \12\ The SAB peer review of RTR Risk Assessment Methodologies is 
available at: http://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf.
    \13\ U.S. EPA. (2009) Chapter 2.9 Chemical Specific Reference 
Values for Formaldehyde in Graphical Arrays of Chemical-Specific 
Health Effect Reference Values for Inhalation Exposures (Final 
Report). U.S. Environmental Protection Agency, Washington DC, EPA/
600/R-09/061, and available online at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003.
---------------------------------------------------------------------------

4. How did we conduct the multipathway exposure and risk screening?
    The EPA conducted a screening analysis examining the potential for 
significant human health risks due to exposures via routes other than 
inhalation (i.e., ingestion). Initially, we determined whether any 
sources in the source category emitted any hazardous air pollutants 
known to be persistent and bioaccumulative in the environment (PB-HAP). 
The PB-HAP compounds or compound classes are identified for the 
screening from the EPA's Air Toxics Risk Assessment Library (available 
at http://www.epa.gov/ttn/fera/risk_atra_vol1.html).
    For the OSWRO source category, we identified emissions of 
polycyclic organic matter (POM) (analyzed as benzo(a)pyrene toxicity 
equivalence factor (TEQ)), polychlorinated biphenyls, 
hexachlorobenzene, chlordane, lindane (gamma hch), methoxyclor, 
toxaphene, heptachlor, and trifluralin. Because one or more of these 
PB-HAP are emitted by at least one facility in the OSWRO source 
category, we proceeded to the next step of the evaluation. In this 
step, we determined whether the facility-specific emissions rates of 
the emitted PB-HAP were large enough to create the potential for 
significant non-inhalation human health risks under reasonable worst-
case conditions. To facilitate this step, we developed emissions rate 
thresholds for several PB-HAP using a hypothetical upper-end screening 
exposure scenario developed for use in conjunction with the EPA's Total 
Risk Integrated Methodology. Fate, Transport, and Ecological Exposure 
(TRIM.FaTE) model. The PB-HAP with emissions rate thresholds are: Lead, 
cadmium, chlorinated dibenzodioxins and furans, mercury compounds, and 
polycyclic organic matter (POM). We conducted a sensitivity analysis on 
the screening scenario to ensure that its key design parameters would 
represent the upper end of the range of possible values, such that it 
would represent a conservative but not impossible scenario. The 
facility-specific emissions rates of these PB-HAP were compared to the 
emission rate threshold values for these PB-HAP to assess the potential 
for significant human health risks via non-inhalation pathways. We call 
this application of the TRIM.FaTE model the Tier I TRIM-screen or Tier 
I screen.
    For the purpose of developing emissions rates for our Tier I TRIM-
screen, we derived emission levels for these PB-HAP (other than lead 
compounds) at which the maximum excess lifetime cancer risk would be 1-
in-1 million (i.e., for polychlorinated dibenzodioxins and furans and 
POM) or, for HAP that cause non-cancer health effects (i.e., cadmium 
compounds and mercury compounds), the maximum hazard quotient would be 
1. If the emissions rate of any PB-HAP included in the Tier I screen 
exceeds the Tier I screening emissions rate for any facility, we 
conduct a second screen, which we call the Tier II TRIM-screen or Tier 
II screen. In the Tier II screen, the location of each facility that 
exceeded the Tier I emission rate is used to refine the assumptions 
associated with the environmental scenario while maintaining the 
exposure scenario assumptions. We then adjust the risk-based Tier I 
screening level for each PB-HAP for each facility based on an 
understanding of how exposure concentrations estimated for the

[[Page 37859]]

screening scenario change with meteorology and environmental 
assumptions. PB-HAP emissions that do not exceed these new Tier II 
screening levels are considered to pose no unacceptable risks. When 
facilities exceed the Tier II screening levels, it does not mean that 
multipathway impacts are significant, only that we cannot rule out that 
possibility based on the results of the screen. These facilities may be 
further evaluated for multipathway risks using the TRIM.FaTE model.
    For further information on the multipathway analysis approach, see 
the Draft Residual Risk Assessment for the Off-Site Waste and Recovery 
Operations Source Category, which is available in the docket for this 
action.
5. How did we assess risks considering emissions control options?
    In addition to assessing baseline inhalation risks and screening 
for potential multipathway risks, we also estimated risks considering 
the potential emission reductions that would be achieved by the control 
options under consideration. In these cases, the expected emission 
reductions were applied to the specific HAP and emission points in the 
RTR emissions dataset to develop corresponding estimates of risk and 
incremental risk reductions.
6. How did we conduct the environmental risk screening assessment?
a. Adverse Environmental Effect
    The EPA has developed a screening approach to examine the potential 
for adverse environmental effects as required under section 
112(f)(2)(A) of the CAA. Section 112(a)(7) of the CAA defines ``adverse 
environmental effect'' as ``any significant and widespread adverse 
effect, which may reasonably be anticipated, to wildlife, aquatic life, 
or other natural resources, including adverse impacts on populations of 
endangered or threatened species or significant degradation of 
environmental quality over broad areas.''
b. Environmental HAP
    The EPA focuses on seven HAP, which we refer to as ``environmental 
HAP,'' in its screening analysis: Five persistent bioaccumulative HAP 
(PB-HAP) and two acid gases. The five PB-HAP are cadmium, dioxins/
furans, polycyclic organic matter (POM), mercury (both inorganic 
mercury and methyl mercury) and lead compounds. The two acid gases are 
hydrogen chloride (HCl) and hydrogen fluoride (HF). The rationale for 
including these seven HAP in the environmental risk screening analysis 
is presented below.
    HAP that persist and bioaccumulate are of particular environmental 
concern because they accumulate in the soil, sediment and water. The 
PB-HAP are taken up, through sediment, soil, water, and/or ingestion of 
other organisms, by plants or animals (e.g., small fish) at the bottom 
of the food chain. As larger and larger predators consume these 
organisms, concentrations of the PB-HAP in the animal tissues increases 
as does the potential for adverse effects. The five PB-HAP we evaluate 
as part of our screening analysis account for 99.8 percent of all PB-
HAP emissions nationally from stationary sources (on a mass basis from 
the 2005 NEI).
    In addition to accounting for almost all of the mass of PB-HAP 
emitted, we note that the TRIM.Fate model that we use to evaluate 
multipathway risk allows us to estimate concentrations of cadmium 
compounds, dioxins/furans, POM and mercury in soil, sediment and water. 
For lead compounds, we currently do not have the ability to calculate 
these concentrations using the TRIM.Fate model. Therefore, to evaluate 
the potential for adverse environmental effects from lead compounds, we 
compare the estimated HEM-modeled exposures from the source category 
emissions of lead with the level of the secondary National Ambient Air 
Quality Standard (NAAQS) for lead.\14\ We consider values below the 
level of the secondary lead NAAQS to be unlikely to cause adverse 
environmental effects.
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    \14\ The secondary lead NAAQS is a reasonable measure of 
determining whether there is an adverse environmental effect since 
it was established considering ``effects on soils, water, crops, 
vegetation, man-made materials, animals, wildlife, weather, 
visibility and climate, damage to and deterioration of property, and 
hazards to transportation, as well as effects on economic values and 
on personal comfort and well-being.'' 73 FR 66964, November 12, 
2008.
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    Due to their well-documented potential to cause direct damage to 
terrestrial plants, we include two acid gases, HCl and HF, in the 
environmental screening analysis. According to the 2005 NEI, HCl and HF 
account for about 99 percent (on a mass basis) of the total acid gas 
HAP emitted by stationary sources in the U.S. In addition to the 
potential to cause direct damage to plants, high concentrations of HF 
in the air have been linked to fluorosis in livestock. Air 
concentrations of these HAP are already calculated as part of the human 
multipathway exposure and risk screening analysis using the HEM3-AERMOD 
air dispersion model, and we are able to use the air dispersion 
modeling results to estimate the potential for an adverse environmental 
effect.
    The EPA acknowledges that other HAP beyond the seven HAP discussed 
above may have the potential to cause adverse environmental effects. 
Therefore, the EPA may include other relevant HAP in its environmental 
risk screening in the future, as modeling science and resources allow. 
The EPA invites comment on the extent to which other HAP emitted by the 
source category may cause adverse environmental effects. Such 
information should include references to peer-reviewed ecological 
effects benchmarks that are of sufficient quality for making regulatory 
decisions, as well as information on the presence of organisms located 
near facilities within the source category that such benchmarks 
indicate could be adversely affected.
c. Ecological Assessment Endpoints and Benchmarks for PB-HAP
    An important consideration in the development of the EPA's 
screening methodology is the selection of ecological assessment 
endpoints and benchmarks. Ecological assessment endpoints are defined 
by the ecological entity (e.g., aquatic communities including fish and 
plankton) and its attributes (e.g., frequency of mortality). Ecological 
assessment endpoints can be established for organisms, populations, 
communities or assemblages, and ecosystems.
    For PB-HAP (other than lead compounds), we evaluated the following 
community-level ecological assessment endpoints to screen for organisms 
directly exposed to HAP in soils, sediment and water:
     Local terrestrial communities (i.e., soil invertebrates, 
plants) and populations of small birds and mammals that consume soil 
invertebrates exposed to PB-HAP in the surface soil.
     Local benthic (i.e., bottom sediment dwelling insects, 
amphipods, isopods and crayfish) communities exposed to PB-HAP in 
sediment in nearby water bodies.
     Local aquatic (water-column) communities (including fish 
and plankton) exposed to PB-HAP in nearby surface waters.
    For PB-HAP (other than lead compounds), we also evaluated the 
following population-level ecological assessment endpoint to screen for 
indirect HAP exposures of top consumers via the bioaccumulation of HAP 
in food chains:
     Piscivorous (i.e., fish-eating) wildlife consuming PB-HAP-

[[Page 37860]]

contaminated fish from nearby water bodies.
    For cadmium compounds, dioxins/furans, POM and mercury, we 
identified the available ecological benchmarks for each assessment 
endpoint. An ecological benchmark represents a concentration of HAP 
(e.g., 0.77 ug of HAP per liter of water) that has been linked to a 
particular environmental effect level (e.g., a no-observed-adverse-
effect level (NOAEL)) through scientific study. For PB-HAP, we 
identified, where possible, ecological benchmarks at the following 
effect levels:
    Probable effect levels (PEL): Level above which adverse effects are 
expected to occur frequently.
    Lowest-observed-adverse-effect level (LOAEL): The lowest exposure 
level tested at which there are biologically significant increases in 
frequency or severity of adverse effects.
    No-observed-adverse-effect levels (NOAEL): The highest exposure 
level tested at which there are no biologically significant increases 
in the frequency or severity of adverse effect.
    We established a hierarchy of preferred benchmark sources to allow 
selection of benchmarks for each environmental HAP at each ecological 
assessment endpoint. In general, the EPA sources that are used at a 
programmatic level (e.g., Office of Water, Superfund Program) were 
used, if available. If not, the EPA benchmarks used in regional 
programs (e.g., Superfund) were used. If benchmarks were not available 
at a programmatic or regional level, we used benchmarks developed by 
other federal agencies (e.g., National Oceanic and Atmospheric 
Organization (NOAA)) or state agencies.
    Benchmarks for all effect levels are not available for all PB-HAP 
and assessment endpoints. In cases where multiple effect levels were 
available for a particular PB-HAP and assessment endpoint, we use all 
of the available effect levels to help us to determine whether 
ecological risks exist and, if so, whether the risks could be 
considered significant and widespread.
d. Ecological Assessment Endpoints and Benchmarks for Acid Gases
    The environmental screening analysis also evaluated potential 
damage and reduced productivity of plants due to direct exposure to 
acid gases in the air. For acid gases, we evaluated the following 
ecological assessment endpoint:
     Local terrestrial plant communities with foliage exposed 
to acidic gaseous HAP in the air.
    The selection of ecological benchmarks for the effects of acid 
gases on plants followed the same approach as for PB-HAP (i.e., we 
examine all of the available chronic benchmarks). For HCl, the EPA 
identified chronic benchmark concentrations. We note that the benchmark 
for chronic HCl exposure to plants is greater than the reference 
concentration for chronic inhalation exposure for human health. This 
means that where the EPA includes regulatory requirements to prevent an 
exceedance of the reference concentration for human health, additional 
analyses for adverse environmental effects of HCL would not be 
necessary.
    For HF, the EPA identified chronic benchmark concentrations for 
plants and evaluated chronic exposures to plants in the screening 
analysis. High concentrations of HF in the air have also been linked to 
fluorosis in livestock. However, the HF concentrations at which 
fluorosis in livestock occur are higher than those at which plant 
damage begins. Therefore, the benchmarks for plants are protective of 
both plants and livestock.
e. Screening Methodology
    For the environmental risk screening analysis, the EPA first 
determined whether any facilities in the OSWRO source category emitted 
any of the seven environmental HAP. For the OSWRO source category, we 
identified emissions of POM, HCl and HF.
    Because one or more of the seven environmental HAP evaluated are 
emitted by at least one facility in the source category, we proceeded 
to the second step of the evaluation.
f. PB-HAP Methodology
    For cadmium, mercury, POM and dioxins/furans, the environmental 
screening analysis consists of two tiers, while lead compounds are 
analyzed differently as discussed earlier. In the first tier, we 
determined whether the maximum facility-specific emission rates of each 
of the emitted environmental HAP were large enough to create the 
potential for adverse environmental effects under reasonable worst-case 
environmental conditions. These are the same environmental conditions 
used in the human multipathway exposure and risk screening analysis.
    To facilitate this step, TRIM.FaTE was run for each PB-HAP under 
hypothetical environmental conditions designed to provide 
conservatively high HAP concentrations. The model was set to maximize 
runoff from terrestrial parcels into the modeled lake, which in turn, 
maximized the chemical concentrations in the water, the sediments, and 
the fish. The resulting media concentrations were then used to back-
calculate a screening threshold emission rate that corresponded to the 
relevant exposure benchmark concentration value for each assessment 
endpoint. To assess emissions from a facility, the reported emission 
rate for each PB-HAP was compared to the screening threshold emission 
rate for that PB-HAP for each assessment endpoint. If emissions from a 
facility do not exceed the Tier I threshold, the facility ``passes'' 
the screen, and therefore, is not evaluated further under the screening 
approach. If emissions from a facility exceed the Tier I threshold, we 
evaluate the facility further in Tier II.
    In Tier II of the environmental screening analysis, the screening 
emission thresholds are adjusted to account for local meteorology and 
the actual location of lakes in the vicinity of facilities that did not 
pass the Tier I screen. The modeling domain for each facility in the 
Tier II analysis consists of eight octants. Each octant contains 5 
modeled soil concentrations at various distances from the facility (5 
soil concentrations x 8 octants = total of 40 soil concentrations per 
facility) and 1 lake with modeled concentrations for water, sediment 
and fish tissue. In the Tier II environmental risk screening analysis, 
the 40 soil concentration points are averaged to obtain an average soil 
concentration for each facility for each PB-HAP. For the water, 
sediment and fish tissue concentrations, the highest value for each 
facility for each pollutant is used. If emission concentrations from a 
facility do not exceed the Tier II threshold, the facility passes the 
screen, and typically is not evaluated further. If emissions from a 
facility exceed the Tier II threshold, the facility does not pass the 
screen and, therefore, may have the potential to cause adverse 
environmental effects. Such facilities are evaluated further to 
investigate factors such as the magnitude and characteristics of the 
area of exceedance.
g. Acid Gas Methodology
    The environmental screening analysis evaluates the potential 
phytotoxicity and reduced productivity of plants due to chronic 
exposure to acid gases. The environmental risk screening methodology 
for acid gases is a single-tier screen that compares the average off-
site ambient air concentration over the modeling domain to ecological 
benchmarks for each of the acid gases. Because air concentrations are 
compared directly to the ecological benchmarks, emission-based 
thresholds are not calculated for acid gases as they

[[Page 37861]]

are in the ecological risk screening methodology for PB-HAPs.
    For purposes of ecological risk screening, the EPA identifies a 
potential for adverse environmental effects to plant communities from 
exposure to acid gases when the average concentration of the HAP around 
a facility exceeds the LOAEL ecological benchmark. In such cases, we 
further investigate factors such as the magnitude and characteristics 
of the area of exceedance (e.g., land use of exceedance area, size of 
exceedance area) to determine if there is an adverse environmental 
effect.
    For further information on the environmental screening analysis 
approach, see the Draft Residual Risk Assessment for the Off-Site Waste 
and Recovery Operations Source Category, which is available in the 
docket for this action.
7. How did we conduct facility-wide assessments?
    To put the source category risks in context, we typically examine 
the risks from the entire ``facility,'' where the facility includes all 
HAP-emitting operations within a contiguous area and under common 
control. In other words, we examine the HAP emissions not only from the 
source category emission points of interest, but also emissions of HAP 
from all other emission sources at the facility for which we have data. 
The emissions data for estimating these ``facility-wide'' risks were 
obtained from the 2005 NEI (available at http://www.epa.gov/ttn/atw/nata2005). We analyzed risks due to the inhalation of HAP that are 
emitted ``facility-wide'' for the populations residing within 50 km of 
each facility, consistent with the methods used for the source category 
analysis described above. For these facility-wide risk analyses, the 
modeled source category risks were compared to the facility-wide risks 
to determine the portion of facility-wide risks that could be 
attributed to the source category addressed in this proposal. We 
specifically examined the facility that was associated with the highest 
estimate of risk and determined the percentage of that risk 
attributable to the source category of interest. The Draft Residual 
Risk Assessment for the Off-Site Waste and Recovery Operations Source 
Category available through the docket for this action provides the 
methodology and results of the facility-wide analyses, including all 
facility-wide risks and the percentage of source category contribution 
to facility-wide risks.
8. How did we consider uncertainties in risk assessment?
    In the Benzene NESHAP, we concluded that risk estimation 
uncertainty should be considered in our decision-making under the ample 
margin of safety framework. Uncertainty and the potential for bias are 
inherent in all risk assessments, including those performed for this 
proposal. Although uncertainty exists, we believe that our approach, 
which used conservative tools and assumptions, ensures that our 
decisions are health protective and environmentally protective. A brief 
discussion of the uncertainties in the RTR emissions dataset, 
dispersion modeling, inhalation exposure estimates and dose-response 
relationships follows below. A more thorough discussion of these 
uncertainties is included in the Draft Residual Risk Assessment for the 
Off-Site Waste and Recovery Operations Source Category, which is 
available in the docket for this action.
a. Uncertainties in the RTR Emissions Dataset
    Although the development of the RTR emissions dataset involved 
quality assurance/quality control processes, the accuracy of emissions 
values will vary depending on the source of the data, the degree to 
which data are incomplete or missing, the degree to which assumptions 
made to complete the datasets are accurate, errors in emission 
estimates and other factors. The emission estimates considered in this 
analysis generally are annual totals for certain years and they do not 
reflect short-term fluctuations during the course of a year or 
variations from year to year. The estimates of peak hourly emission 
rates for the acute effects screening assessment were based on an 
emission adjustment factor applied to the average annual hourly 
emission rates, which are intended to account for emission fluctuations 
due to normal facility operations.
b. Uncertainties in Dispersion Modeling
    We recognize there is uncertainty in ambient concentration 
estimates associated with any model, including the EPA's recommended 
regulatory dispersion model, AERMOD. In using a model to estimated 
ambient pollutant concentrations, the user chooses certain options to 
apply. For RTR assessments, we select some model options that have the 
potential to overestimate ambient air concentrations (e.g., not 
including plume depletion or pollutant transformation). We select other 
model options that have the potential to underestimate ambient impacts 
(e.g., not including building downwash). Other options that we select 
have the potential to either under- or overestimate ambient levels 
(e.g., meteorology and receptor locations). On balance, considering the 
directional nature of the uncertainties commonly present in ambient 
concentrations estimated by dispersion models, the approach we apply in 
the RTR assessments should yield unbiased estimates of ambient HAP 
concentrations.
c. Uncertainties in Inhalation Exposure
    The EPA did not include the effects of human mobility on exposures 
in the assessment. Specifically, short-term mobility and long-term 
mobility between census blocks in the modeling domain were not 
considered.\15\ The approach of not considering short or long-term 
population mobility does not bias the estimate of the theoretical MIR 
(by definition), nor does it affect the estimate of cancer incidence 
because the total population number remains the same. It does, however, 
affect the shape of the distribution of individual risks across the 
affected population, shifting it toward higher estimated individual 
risks at the upper end and reducing the number of people estimated to 
be at lower risks, thereby increasing the estimated number of people at 
specific high risk levels (e.g., 1-in-10 thousand or 1-in-1 million).
---------------------------------------------------------------------------

    \15\ Short-term mobility is movement from one micro-environment 
to another over the course of hours or days. Long-term mobility is 
movement from one residence to another over the course of a 
lifetime.
---------------------------------------------------------------------------

    In addition, the assessment predicted the chronic exposures at the 
centroid of each populated census block as surrogates for the exposure 
concentrations for all people living in that block. Using the census 
block centroid to predict chronic exposures tends to over-predict 
exposures for people in the census block who live farther from the 
facility and under-predict exposures for people in the census block who 
live closer to the facility. Thus, using the census block centroid to 
predict chronic exposures may lead to a potential understatement or 
overstatement of the true maximum impact, but is an unbiased estimate 
of average risk and incidence. We reduce this uncertainty by analyzing 
large census blocks near facilities using aerial imagery and adjusting 
the location of the block centroid to better represent the population 
in the block, as well as adding additional receptor locations where the 
block population is not well represented by a single location.
    The assessment evaluates the cancer inhalation risks associated 
with

[[Page 37862]]

pollutant exposures over a 70-year period, which is the assumed 
lifetime of an individual. In reality, both the length of time that 
modeled emission sources at facilities actually operate (i.e., more or 
less than 70 years) and the domestic growth or decline of the modeled 
industry (i.e., the increase or decrease in the number or size of 
domestic facilities) will influence the future risks posed by a given 
source or source category. Depending on the characteristics of the 
industry, these factors will, in most cases, result in an overestimate 
both in individual risk levels and in the total estimated number of 
cancer cases. However, in the unlikely scenario where a facility 
maintains, or even increases, its emissions levels over a period of 
more than 70 years, residents live beyond 70 years at the same 
location, and the residents spend most of their days at that location, 
then the cancer inhalation risks could potentially be underestimated. 
However, annual cancer incidence estimates from exposures to emissions 
from these sources would not be affected by the length of time an 
emissions source operates.
    The exposure estimates used in these analyses assume chronic 
exposures to ambient (outdoor) levels of pollutants. Because most 
people spend the majority of their time indoors, actual exposures may 
not be as high, depending on the characteristics of the pollutants 
modeled. For many of the HAP, indoor levels are roughly equivalent to 
ambient levels, but for very reactive pollutants or larger particles, 
indoor levels are typically lower. This factor has the potential to 
result in an overestimate of 25 to 30 percent of exposures.\16\
---------------------------------------------------------------------------

    \16\ U.S. EPA. National-Scale Air Toxics Assessment for 1996. 
(EPA 453/R-01-003; January 2001; page 85.)
---------------------------------------------------------------------------

    In addition to the uncertainties highlighted above, there are 
several factors specific to the acute exposure assessment that should 
be highlighted. The accuracy of an acute inhalation exposure assessment 
depends on the simultaneous occurrence of independent factors that may 
vary greatly, such as hourly emissions rates, meteorology and human 
activity patterns. In this assessment, we assume that individuals 
remain for 1 hour at the point of maximum ambient concentration as 
determined by the co-occurrence of peak emissions and worst-case 
meteorological conditions. These assumptions would tend to be worst-
case actual exposures as it is unlikely that a person would be located 
at the point of maximum exposure when peak emissions and worst-case 
meteorological conditions occur simultaneously.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from 
chronic exposures and non-cancer effects from both chronic and acute 
exposures. Some uncertainties may be considered quantitatively, and 
others generally are expressed in qualitative terms. We note as a 
preface to this discussion a point on dose-response uncertainty that is 
brought out in the EPA's 2005 Cancer Guidelines; namely, that ``the 
primary goal of EPA actions is protection of human health; accordingly, 
as an Agency policy, risk assessment procedures, including default 
options that are used in the absence of scientific data to the 
contrary, should be health protective'' (EPA 2005 Cancer Guidelines, 
pages 1-7). This is the approach followed here as summarized in the 
next several paragraphs. A complete detailed discussion of 
uncertainties and variability in dose-response relationships is given 
in the Draft Residual Risk Assessment for the Off-Site Waste and 
Recovery Operations Source Category, which is available in the docket 
for this action.
    Cancer URE values used in our risk assessments are those that have 
been developed to generally provide an upper bound estimate of risk. 
That is, they represent a ``plausible upper limit to the true value of 
a quantity'' (although this is usually not a true statistical 
confidence limit).\17\ In some circumstances, the true risk could be as 
low as zero; however, in other circumstances the risk could be 
greater.\18\ When developing an upper bound estimate of risk and to 
provide risk values that do not underestimate risk, health-protective 
default approaches are generally used. To err on the side of ensuring 
adequate health protection, the EPA typically uses the upper bound 
estimates rather than lower bound or central tendency estimates in our 
risk assessments, an approach that may have limitations for other uses 
(e.g., priority-setting or expected benefits analysis).
---------------------------------------------------------------------------

    \17\ IRIS glossary (http://www.epa.gov/NCEA/iris/help_gloss.htm).
    \18\ An exception to this is the URE for benzene, which is 
considered to cover a range of values, each end of which is 
considered to be equally plausible, and which is based on maximum 
likelihood estimates.
---------------------------------------------------------------------------

    Chronic non-cancer RfC and reference dose (RfD) values represent 
chronic exposure levels that are intended to be health-protective 
levels. Specifically, these values provide an estimate (with 
uncertainty spanning perhaps an order of magnitude) of a continuous 
inhalation exposure (RfC) or a daily oral exposure (RfD) to the human 
population (including sensitive subgroups) that is likely to be without 
an appreciable risk of deleterious effects during a lifetime. To derive 
values that are intended to be ``without appreciable risk,'' the 
methodology relies upon an uncertainty factor (UF) approach (U.S. EPA, 
1993, 1994) which considers uncertainty, variability and gaps in the 
available data. The UF are applied to derive reference values that are 
intended to protect against appreciable risk of deleterious effects. 
The UF are commonly default values,\19\ e.g., factors of 10 or 3, used 
in the absence of compound-specific data; where data are available, UF 
may also be developed using compound-specific information. When data 
are limited, more assumptions are needed and more UF are used. Thus, 
there may be a greater tendency to overestimate risk in the sense that 
further study might support development of reference values that are 
higher (i.e., less potent) because fewer default assumptions are 
needed. However, for some pollutants, it is possible that risks may be 
underestimated.
---------------------------------------------------------------------------

    \19\ According to the NRC report, Science and Judgment in Risk 
Assessment (NRC, 1994) ``[Default] options are generic approaches, 
based on general scientific knowledge and policy judgment, that are 
applied to various elements of the risk assessment process when the 
correct scientific model is unknown or uncertain.'' The 1983 NRC 
report, Risk Assessment in the Federal Government: Managing the 
Process, defined default option as ``the option chosen on the basis 
of risk assessment policy that appears to be the best choice in the 
absence of data to the contrary'' (NRC, 1983a, p. 63). Therefore, 
default options are not rules that bind the Agency; rather, the 
Agency may depart from them in evaluating the risks posed by a 
specific substance when it believes this to be appropriate. In 
keeping with EPA's goal of protecting public health and the 
environment, default assumptions are used to ensure that risk to 
chemicals is not underestimated (although defaults are not intended 
to overtly overestimate risk). See EPA, 2004, An Examination of EPA 
Risk Assessment Principles and Practices, EPA/100/B-04/001 available 
at: http://www.epa.gov/osa/pdfs/ratf-final.pdf.
---------------------------------------------------------------------------

    While collectively termed ``UF,'' these factors account for a 
number of different quantitative considerations when using observed 
animal (usually rodent) or human toxicity data in the development of 
the RfC. The UF are intended to account for: (1) Variation in 
susceptibility among the members of the human population (i.e., inter-
individual variability); (2) uncertainty in extrapolating from 
experimental animal data to humans (i.e., interspecies

[[Page 37863]]

differences); (3) uncertainty in extrapolating from data obtained in a 
study with less-than-lifetime exposure (i.e., extrapolating from sub-
chronic to chronic exposure); (4) uncertainty in extrapolating the 
observed data to obtain an estimate of the exposure associated with no 
adverse effects; and (5) uncertainty when the database is incomplete or 
there are problems with the applicability of available studies.
    Many of the UF used to account for variability and uncertainty in 
the development of acute reference values are quite similar to those 
developed for chronic durations, but they more often use individual UF 
values that may be less than 10. The UF are applied based on chemical-
specific or health effect-specific information (e.g., simple irritation 
effects do not vary appreciably between human individuals, hence a 
value of 3 is typically used), or based on the purpose for the 
reference value (see the following paragraph). The UF applied in acute 
reference value derivation include: (1) Heterogeneity among humans; (2) 
uncertainty in extrapolating from animals to humans; (3) uncertainty in 
lowest observed adverse effect (exposure) level to no observed adverse 
effect (exposure) level adjustments; and (4) uncertainty in accounting 
for an incomplete database on toxic effects of potential concern. 
Additional adjustments are often applied to account for uncertainty in 
extrapolation from observations at one exposure duration (e.g., 4 
hours) to derive an acute reference value at another exposure duration 
(e.g., 1 hour).
    Not all acute reference values are developed for the same purpose 
and care must be taken when interpreting the results of an acute 
assessment of human health effects relative to the reference value or 
values being exceeded. Where relevant to the estimated exposures, the 
lack of short-term dose-response values at different levels of severity 
should be factored into the risk characterization as potential 
uncertainties.
    Although every effort is made to identify appropriate human health 
effect dose-response assessment values for all pollutants emitted by 
the sources in this risk assessment, some HAP emitted by this source 
category are lacking dose-response assessments. Accordingly, these 
pollutants cannot be included in the quantitative risk assessment, 
which could result in quantitative estimates understating HAP risk. To 
help to alleviate this potential underestimate, where we conclude 
similarity with a HAP for which a dose-response assessment value is 
available, we use that value as a surrogate for the assessment of the 
HAP for which no value is available. To the extent use of surrogates 
indicates appreciable risk, we may identify a need to increase priority 
for new IRIS assessment of that substance. We additionally note that, 
generally speaking, HAP of greatest concern due to environmental 
exposures and hazard are those for which dose-response assessments have 
been performed, reducing the likelihood of understating risk. Further, 
HAP not included in the quantitative assessment are assessed 
qualitatively and considered in the risk characterization that informs 
the risk management decisions, including with regard to consideration 
of HAP reductions achieved by various control options.
    For a group of compounds that are not speciated (e.g., glycol 
ethers), we conservatively use the most protective reference value of 
an individual compound in that group to estimate risk. Similarly, for 
an individual compound in a group (e.g., ethylene glycol diethyl ether) 
that does not have a specified reference value, we also apply the most 
protective reference value from the other compounds in the group to 
estimate risk.
e. Uncertainties in the Multipathway Assessment
    For each source category, we generally rely on site-specific levels 
of PB-HAP emissions to determine whether a refined assessment of the 
impacts from multipathway exposures is necessary. This determination is 
based on the results of a two-tiered screening analysis that relies on 
the outputs from models that estimate environmental pollutant 
concentrations and human exposures for four PB-HAP. Two important types 
of uncertainty associated with the use of these models in RTR risk 
assessments and inherent to any assessment that relies on environmental 
modeling are model uncertainty and input uncertainty.\20\
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    \20\ In the context of this discussion, the term ``uncertainty'' 
as it pertains to exposure and risk encompasses both variability in 
the range of expected inputs and screening results due to existing 
spatial, temporal, and other factors, as well as uncertainty in 
being able to accurately estimate the true result.
---------------------------------------------------------------------------

    Model uncertainty concerns whether the selected models are 
appropriate for the assessment being conducted and whether they 
adequately represent the actual processes that might occur for that 
situation. An example of model uncertainty is the question of whether 
the model adequately describes the movement of a pollutant through the 
soil. This type of uncertainty is difficult to quantify. However, based 
on feedback received from previous EPA Science Advisory Board reviews 
and other reviews, we are confident that the models used in the screen 
are appropriate and state-of-the-art for the multipathway risk 
assessments conducted in support of RTR.
    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the assessment at hand. For Tier 
I of the multipathway screen, we configured the models to avoid 
underestimating exposure and risk. This was accomplished by selecting 
upper-end values from nationally-representative data sets for the more 
influential parameters in the environmental model, including selection 
and spatial configuration of the area of interest, lake location and 
size, meteorology, surface water and soil characteristics and structure 
of the aquatic food web. We also assume an ingestion exposure scenario 
and values for human exposure factors that represent reasonable maximum 
exposures.
    In Tier II of the multipathway assessment, we refine the model 
inputs to account for meteorological patterns in the vicinity of the 
facility versus using upper-end national values and we identify the 
actual location of lakes near the facility rather than the default lake 
location that we apply in Tier I. By refining the screening approach in 
Tier II to account for local geographical and meteorological data, we 
decrease the likelihood that concentrations in environmental media are 
overestimated, thereby increasing the usefulness of the screen. The 
assumptions and the associated uncertainties regarding the selected 
ingestion exposure scenario are the same for Tier I and Tier II.
    For both Tiers I and II of the multipathway assessment, our 
approach to addressing model input uncertainty is generally cautious. 
We choose model inputs from the upper end of the range of possible 
values for the influential parameters used in the models, and we assume 
that the exposed individual exhibits ingestion behavior that would lead 
to a high total exposure. This approach reduces the likelihood of not 
identifying high risks for adverse impacts.
    Despite the uncertainties, when individual pollutants or facilities 
do screen out, we are confident that the potential for adverse 
multipathway impacts on human health is very low. On the other hand, 
when individual pollutants or facilities do not screen out, it does not 
mean that multipathway impacts are significant, only that we cannot 
rule out that possibility and that a refined multipathway analysis for 
the

[[Page 37864]]

site might be necessary to obtain a more accurate risk characterization 
for the source category.
    For further information on uncertainties and the Tier I and II 
screening methods, refer to the risk document Appendix 4, ``Technical 
Support Document for TRIM-Based Multipathway Tiered Screening 
Methodology for RTR.''
f. Uncertainties in the Environmental Risk Screening Assessment
    For each source category, we generally rely on site-specific levels 
of environmental HAP emissions to perform an environmental screening 
assessment. The environmental screening assessment is based on the 
outputs from models that estimate environmental HAP concentrations. The 
same models, specifically the TRIM.FaTE multipathway model and the 
AERMOD air dispersion model, are used to estimate environmental HAP 
concentrations for both the human multipathway screening analysis and 
for the environmental screening analysis. Therefore, both screening 
assessments have similar modeling uncertainties.
    Two important types of uncertainty associated with the use of these 
models in RTR environmental screening assessments--and inherent to any 
assessment that relies on environmental modeling--are model uncertainty 
and input uncertainty.\21\
---------------------------------------------------------------------------

    \21\ In the context of this discussion, the term 
``uncertainty,'' as it pertains to exposure and risk assessment, 
encompasses both variability in the range of expected inputs and 
screening results due to existing spatial, temporal, and other 
factors, as well as uncertainty in being able to accurately estimate 
the true result.
---------------------------------------------------------------------------

    Model uncertainty concerns whether the selected models are 
appropriate for the assessment being conducted and whether they 
adequately represent the movement and accumulation of environmental HAP 
emissions in the environment. For example, does the model adequately 
describe the movement of a pollutant through the soil? This type of 
uncertainty is difficult to quantify. However, based on feedback 
received from previous EPA Science Advisory Board reviews and other 
reviews, we are confident that the models used in the screen are 
appropriate and state-of-the-art for the environmental risk assessments 
conducted in support of our RTR analyses.
    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the assessment at hand. For Tier 
I of the environmental screen for PB-HAP, we configured the models to 
avoid underestimating exposure and risk to reduce the likelihood that 
the results indicate the risks are lower than they actually are. This 
was accomplished by selecting upper-end values from nationally-
representative data sets for the more influential parameters in the 
environmental model, including selection and spatial configuration of 
the area of interest, the location and size of any bodies of water, 
meteorology, surface water and soil characteristics and structure of 
the aquatic food web. In Tier I, we used the maximum facility-specific 
emissions for the PB-HAP (other than lead compounds, which were 
evaluated by comparison to the secondary lead NAAQS) that were included 
in the environmental screening assessment and each of the media when 
comparing to ecological benchmarks. This is consistent with the 
conservative design of Tier I of the screen. In Tier II of the 
environmental screening analysis for PB-HAP, we refine the model inputs 
to account for meteorological patterns in the vicinity of the facility 
versus using upper-end national values, and we identify the locations 
of water bodies near the facility location. By refining the screening 
approach in Tier II to account for local geographical and 
meteorological data, we decrease the likelihood that concentrations in 
environmental media are overestimated, thereby increasing the 
usefulness of the screen. To better represent widespread impacts, the 
modeled soil concentrations are averaged in Tier II to obtain one 
average soil concentration value for each facility and for each PB-HAP. 
For PB-HAP concentrations in water, sediment and fish tissue, the 
highest value for each facility for each pollutant is used.
    For the environmental screening assessment for acid gases, we 
employ a single-tiered approach. We use the modeled air concentrations 
and compare those with ecological benchmarks.
    For both Tiers I and II of the environmental screening assessment, 
our approach to addressing model input uncertainty is generally 
cautious. We choose model inputs from the upper end of the range of 
possible values for the influential parameters used in the models, and 
we assume that the exposed individual exhibits ingestion behavior that 
would lead to a high total exposure. This approach reduces the 
likelihood of not identifying potential risks for adverse environmental 
impacts.
    Uncertainty also exists in the ecological benchmarks for the 
environmental risk screening analysis. We established a hierarchy of 
preferred benchmark sources to allow selection of benchmarks for each 
environmental HAP at each ecological assessment endpoint. In general, 
EPA benchmarks used at a programmatic level (e.g., Office of Water, 
Superfund Program) were used if available. If not, we used EPA 
benchmarks used in regional programs (e.g., Superfund Program). If 
benchmarks were not available at a programmatic or regional level, we 
used benchmarks developed by other agencies (e.g., NOAA) or by state 
agencies.
    In all cases (except for lead compounds, which were evaluated 
through a comparison to the NAAQS), we searched for benchmarks at the 
following three effect levels, as described in section III.A.6 of this 
preamble:
    1. A no-effect level (i.e., NOAEL).
    2. Threshold-effect level (i.e., LOAEL).
    3. Probable effect level (i.e., PEL).
    For some ecological assessment endpoint/environmental HAP 
combinations, we could identify benchmarks for all three effect levels, 
but for most, we could not. In one case, where different agencies 
derived significantly different numbers to represent a threshold for 
effect, we included both. In several cases, only a single benchmark was 
available. In cases where multiple effect levels were available for a 
particular PB-HAP and assessment endpoint, we used all of the available 
effect levels to help us to determine whether risk exists and if the 
risks could be considered significant and widespread.
    The EPA evaluated the following seven HAP in the environmental risk 
screening assessment: cadmium, dioxins/furans, POM, mercury (both 
inorganic mercury and methyl mercury), lead compounds, HCl and HF. 
These seven HAP represent pollutants that can cause adverse impacts for 
plants and animals either through direct exposure to HAP in the air or 
through exposure to HAP that is deposited from the air onto soils and 
surface waters. These seven HAP also represent those HAP for which we 
can conduct a meaningful environmental risk screening assessment. For 
other HAP not included in our screening assessment, the model has not 
been parameterized such that it can be used for that purpose. In some 
cases, depending on the HAP, we may not have appropriate multipathway 
models that allow us to predict the concentration of that pollutant. 
The EPA acknowledges that other HAP beyond the seven HAP that we are 
evaluating may have the potential to cause adverse environmental 
effects and, therefore, the

[[Page 37865]]

EPA may evaluate other relevant HAP in the future, as modeling science 
and resources allow.
    Further information on uncertainties and the Tier I and II 
environmental screening methods is provided in Appendix 5 of the 
document ``Technical Support Document for TRIM-Based Multipathway 
Tiered Screening Methodology for RTR: Summary of Approach and 
Evaluation.'' Also, see the Draft Residual Risk Assessment for the Off-
Site Waste and Recovery Operations Source Category, available in the 
docket for this action.

B. How did we consider the risk results in making decisions for this 
proposal?

    As discussed in section II.A of this preamble, in evaluating and 
developing standards under section 112(f)(2), we apply a two-step 
process to address residual risk. In the first step, the EPA determines 
whether risks are acceptable. This determination ``considers all health 
information, including risk estimation uncertainty, and includes a 
presumptive limit on maximum individual lifetime [cancer] risk (MIR) 
\22\ of approximately [1-in-10 thousand] [i.e., 100-in-1 million].'' 54 
FR 38045, September 14, 1989. If risks are unacceptable, the EPA must 
determine the emissions standards necessary to bring risks to an 
acceptable level without considering costs. In the second step of the 
process, the EPA considers whether the emissions standards provide an 
ample margin of safety ``in consideration of all health information, 
including the number of persons at risk levels higher than 
approximately 1-in-1 million, as well as other relevant factors, 
including costs and economic impacts, technological feasibility, and 
other factors relevant to each particular decision.'' Id. The EPA must 
promulgate tighter emission standards if necessary to provide an ample 
margin of safety.
---------------------------------------------------------------------------

    \22\ Although defined as ``maximum individual risk,'' MIR refers 
only to cancer risk. MIR, one metric for assessing cancer risk, is 
the estimated risk were an individual exposed to the maximum level 
of a pollutant for a lifetime.
---------------------------------------------------------------------------

    In past residual risk actions, the EPA considered a number of human 
health risk metrics associated with emissions from the categories under 
review, including the MIR, the number of persons in various risk 
ranges, cancer incidence, the maximum non-cancer HI and the maximum 
acute non-cancer hazard. See, e.g., 72 FR 25138, May 3, 2007; 71 FR 
42724, July 27, 2006. The EPA considered this health information for 
both actual and MACT-allowable emissions. See, e.g., 75 FR 65068, 
October 21, 2010; 75 FR 80220, December 21, 2010; 76 FR 29032, May 19, 
2011. The EPA also discussed risk estimation uncertainties and 
considered the uncertainties in the determination of acceptable risk 
and ample margin of safety in these past actions. The EPA considered 
this same type of information in support of this action.
    The agency is considering these various measures of health 
information to inform our determinations of risk acceptability and 
ample margin of safety under CAA section 112(f). As explained in the 
Benzene NESHAP, ``the first step judgment on acceptability cannot be 
reduced to any single factor'' and thus ``[t]he Administrator believes 
that the acceptability of risk under [previous] section 112 is best 
judged on the basis of a broad set of health risk measures and 
information.'' 54 FR 38046, September 14, 1989. Similarly, with regard 
to the ample margin of safety determination, ``the Agency again 
considers all of the health risk and other health information 
considered in the first step. Beyond that information, additional 
factors relating to the appropriate level of control will also be 
considered, including cost and economic impacts of controls, 
technological feasibility, uncertainties, and any other relevant 
factors.'' Id.
    The Benzene NESHAP approach provides flexibility regarding factors 
the EPA may consider in making determinations and how the EPA may weigh 
those factors for each source category. In responding to comment on our 
policy under the Benzene NESHAP, the EPA explained that:

    ``[t]he policy chosen by the Administrator permits consideration 
of multiple measures of health risk. Not only can the MIR figure be 
considered, but also incidence, the presence of non-cancer health 
effects, and the uncertainties of the risk estimates. In this way, 
the effect on the most exposed individuals can be reviewed as well 
as the impact on the general public. These factors can then be 
weighed in each individual case. This approach complies with the 
Vinyl Chloride mandate that the Administrator ascertain an 
acceptable level of risk to the public by employing [her] expertise 
to assess available data. It also complies with the Congressional 
intent behind the CAA, which did not exclude the use of any 
particular measure of public health risk from the EPA's 
consideration with respect to CAA section 112 regulations, and 
thereby implicitly permits consideration of any and all measures of 
health risk which the Administrator, in [her] judgment, believes are 
appropriate to determining what will `protect the public health'.''

See 54 FR at 38057, September 14, 1989. Thus, the level of the MIR is 
only one factor to be weighed in determining acceptability of risks. 
The Benzene NESHAP explained that ``an MIR of approximately one in 10 
thousand should ordinarily be the upper end of the range of 
acceptability. As risks increase above this benchmark, they become 
presumptively less acceptable under CAA section 112, and would be 
weighed with the other health risk measures and information in making 
an overall judgment on acceptability. Or, the Agency may find, in a 
particular case, that a risk that includes MIR less than the 
presumptively acceptable level is unacceptable in the light of other 
health risk factors.'' Id. at 38045. Similarly, with regard to the 
ample margin of safety analysis, the EPA stated in the Benzene NESHAP 
that: ``EPA believes the relative weight of the many factors that can 
be considered in selecting an ample margin of safety can only be 
determined for each specific source category. This occurs mainly 
because technological and economic factors (along with the health-
related factors) vary from source category to source category.'' Id. at 
38061. We also consider the uncertainties associated with the various 
risk analyses, as discussed earlier in this preamble, in our 
determinations of acceptability and ample margin of safety.
    The EPA notes that it has not considered certain health information 
to date in making residual risk determinations. At this time, we do not 
attempt to quantify those HAP risks that may be associated with 
emissions from other facilities that do not include the source 
categories in question, mobile source emissions, natural source 
emissions, persistent environmental pollution or atmospheric 
transformation in the vicinity of the sources in these categories.
    The agency understands the potential importance of considering an 
individual's total exposure to HAP in addition to considering exposure 
to HAP emissions from the source category and facility. We recognize 
that such consideration may be particularly important when assessing 
non-cancer risks, where pollutant-specific exposure health reference 
levels (e.g., RfCs) are based on the assumption that thresholds exist 
for adverse health effects. For example, the agency recognizes that, 
although exposures attributable to emissions from a source category or 
facility alone may not indicate the potential for increased risk of 
adverse non-cancer health effects in a population, the exposures 
resulting from emissions from the facility in combination with 
emissions from all of the other sources (e.g., other facilities) to 
which an individual is exposed may be sufficient to result in increased 
risk of adverse non-cancer health effects. In

[[Page 37866]]

May 2010, the SAB advised the EPA ``that RTR assessments will be most 
useful to decision makers and communities if results are presented in 
the broader context of aggregate and cumulative risks, including 
background concentrations and contributions from other sources in the 
area.'' \23\
---------------------------------------------------------------------------

    \23\ EPA's responses to this and all other key recommendations 
of the SAB's advisory on RTR risk assessment methodologies (which is 
available at: http://yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf) 
are outlined in a memo in this proposed rule docket from David 
Guinnup entitled, EPA's Actions in Response to the Key 
Recommendations of the SAB Review of RTR Risk Assessment 
Methodologies.
---------------------------------------------------------------------------

    In response to the SAB recommendations, the EPA is incorporating 
cumulative risk analyses into its RTR risk assessments, including those 
reflected in this proposal. The agency is: (1) Conducting facility-wide 
assessments, which include source category emission points as well as 
other emission points within the facilities; (2) considering sources in 
the same category whose emissions result in exposures to the same 
individuals; and (3) for some persistent and bioaccumlative pollutants, 
analyzing the ingestion route of exposure. In addition, the RTR risk 
assessments have always considered aggregate cancer risk from all 
carcinogens and aggregate non-cancer hazard indices from all non-
carcinogens affecting the same target organ system.
    Although we are interested in placing source category and facility-
wide HAP risks in the context of total HAP risks from all sources 
combined in the vicinity of each source, we are concerned about the 
uncertainties of doing so. Because of the contribution to total HAP 
risk from emission sources other than those that we have studied in 
depth during this RTR review (i.e., those sources located at facilities 
within the source category), such estimates of total HAP risks would 
have significantly greater associated uncertainties than the source 
category or facility-wide estimates. Such aggregate or cumulative 
assessments would compound those uncertainties, making the assessments 
too unreliable.

C. How did we perform the technology review?

    Our technology review focused on the identification and evaluation 
of developments in practices, processes and control technologies that 
have occurred since the MACT standards were promulgated. Where we 
identified such developments, in order to inform our decision of 
whether it is ``necessary'' to revise the emissions standards, we 
analyzed the technical feasibility of applying these developments, and 
the estimated costs, energy implications, non-air environmental 
impacts, as well as considering the emission reductions. We also 
considered the appropriateness of applying controls to new sources 
versus retrofitting existing sources.
    Based on our analyses of the available data and information, we 
identified potential developments in practices, processes and control 
technologies. For this exercise, we considered any of the following to 
be a ``development'':

     Any add-on control technology or other equipment that 
was not identified and considered during development of the original 
MACT standards.
     Any improvements in add-on control technology or other 
equipment (that were identified and considered during development of 
the original MACT standards) that could result in additional 
emissions reduction.
     Any work practice or operational procedure that was not 
identified or considered during development of the original MACT 
standards.
     Any process change or pollution prevention alternative 
that could be broadly applied to the industry and that was not 
identified or considered during development of the original MACT 
standards.
     Any significant changes in the cost (including cost 
effectiveness) of applying controls (including controls the EPA 
considered during the development of the original MACT standards).

    We reviewed a variety of data sources in our investigation of 
potential practices, processes or controls to consider. Among the 
sources we reviewed were the NESHAP for various industries that were 
promulgated since the MACT standards reviewed in this action. We 
reviewed the regulatory requirements and/or technical analyses 
associated with these regulatory actions to identify any practices, 
processes and control technologies considered in these efforts that 
could be applied to emission sources in the OSWRO source category, as 
well as the costs, non-air impacts and energy implications associated 
with the use of these technologies. Additionally, we requested 
information from facilities regarding developments in practices, 
processes or control technology. Finally, we reviewed information from 
other sources, such as state and/or local permitting agency databases 
and industry-supported databases.

IV. Analytical Results and Proposed Decisions

    This section of the preamble provides the results of our RTR for 
the OSWRO source category and our proposed decisions concerning changes 
to the OSWRO NESHAP.

A. What are the results of the risk assessment and analyses?

1. Inhalation Risk Assessment Results
    Table 2 of this preamble provides a summary of the results of the 
inhalation risk assessment for the source category.

                                   Table 2--Off-Site Waste and Recovery Operations Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
  Maximum individual cancer risk (in 1 million) \a\                                                Maximum chronic non-cancer
------------------------------------------------------                              Estimated               TOSHI \b\
                                                        Estimated population at   annual cancer --------------------------------
                                            MACT-      increased risk levels of     incidence                         MACT-      Maximum screening acute
        Actual emissions level            allowable             cancer             (cases per        Actual         allowable       non-cancer HQ \d\
                                          emissions                                   year)         emissions       emissions
                                          level \c\                                                   level           level
--------------------------------------------------------------------------------------------------------------------------------------------------------
9....................................              20  >= 1-in-1 million:                  0.02             0.6               1  HQREL = 1 (glycol
                                                        210,000.                                                                  ethers)
                                                       >= 10-in-1 million: 0...
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Estimated maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\b\ Maximum TOSHI. The target organ with the highest TOSHI for the OSWRO source category for both actual and MACT-allowable emissions is the respiratory
  system.
\c\ The development of allowable emission estimates can be found in the memo entitled MACT-Allowable Emissions for the Off-Site Waste and Recovery
  Operations Source Category, which is available in the docket for this action.
\d\ The maximum off-site acute value of 1 for actuals is driven by emissions of glycol ethers. See Section III.A.E for an explanation of acute dose-
  response values. Acute assessments are not performed with MACT-allowable emissions.


[[Page 37867]]

    The inhalation risk modeling performed to estimate risks based on 
actual and MACT-allowable emissions relied primarily on data from the 
CAA section 114 questionnaire responses and the NEI. The results of the 
chronic inhalation cancer risk assessment indicate that, based on 
estimates of current actual emissions, the maximum lifetime individual 
cancer risk posed by the OSWRO source category is 9-in-1 million, with 
emissions of benzidine and 2,4-toluene diamine accounting for the 
majority of the risk. The total estimated cancer incidence from the 
OSWRO source category based on the actual emissions levels is 0.02 
excess cancer cases per year, or one case every 50 years, with 
emissions of benzidine and 2,4-toluene diamine contributing to the 
majority of the incidence. In addition, we note that approximately 
210,000 people are estimated to have cancer risks greater than or equal 
to 1-in-1 million as a result of actual emissions from this source 
category. When considering MACT-allowable emissions, the maximum 
individual lifetime cancer risk is estimated to be up to 20-in-1 
million, driven by emissions of benzidine and 2,4-toluene diamine. Due 
to the way MACT-allowable risks were calculated, estimates of 
population exposure and cancer incidence are not available, but would 
be greater than those estimates presented based on actual emissions. 
However, since the MIR based on MACT-allowable emissions is 20-in-1 
million, there are no people exposed to cancer risks greater than 100-
in-1 million.
    The maximum modeled chronic non-cancer TOSHI value for the OSWRO 
source category based on actual emissions was estimated to be 0.6, with 
emissions of chlorine contributing to the majority of the TOSHI. There 
are no people estimated to have exposure to TOSHI levels greater than 1 
as a result of actual emissions from this source category. When 
considering MACT-allowable emissions, the maximum chronic non-cancer 
TOSHI value was estimated to be up to 1, driven by emissions of 
chlorine. There are no people estimated to have exposure to TOSHI 
levels greater than 1 as a result of emissions at the MACT-allowable 
levels from this source category.
    Our screening analysis for worst-case acute impacts based on actual 
emissions indicates that an HQ value of 1 is not exceeded for any 
pollutants at any facility, indicating that the HAP emissions are 
believed to be without appreciable risk of acute health effects. In 
characterizing the potential for acute non-cancer risks of concern, it 
is important to remember the upward bias of these exposure estimates 
(e.g., worst-case meteorology coinciding with a person located at the 
point of maximum concentration during the hour) and to consider the 
results along with the conservative estimates used to develop peak 
hourly emissions as described earlier. Refer to Appendix 6 of the Draft 
Residual Risk Assessment for the Off-Site Waste and Recovery Operations 
Source Category in the docket for this action for the detailed acute 
risk results.
2. Multipathway Risk Screening Results
    Multiple facilities reported emissions of PB-HAP, including 2-
acetylaminofluorene (a POM compound), heptachlor, and trifluralin. Only 
one facility reported emissions of a PB-HAP that has an available RTR 
multipathway screening value: 2-acetylaminofluorene, a polycylic 
organic matter (POM) compound that was analyzed as benzo(a)pyrene TEQ. 
Reported emissions of the POM 2-acetylaminofluorene are below the 
multipathway screening level for this compound, indicating low 
potential for multipathway risks as a result of emissions of this PB-
HAP. The remaining PB-HAP do not currently have RTR multipathway 
screening values, and they were not evaluated for potential non-
inhalation risks. These HAP, however, are not emitted in appreciable 
quantities from OSWRO facilities. (For more information on PB-HAP 
emitted from this source category, please see the Draft Residual Risk 
Assessment for the Off-Site Waste and Recovery Operations Source 
Category document available in the docket for this action.)
3. Environmental Risk Screening Results
    As described in section III.A.5, we conducted an environmental risk 
screening assessment for the OSWRO source category. Emissions of three 
environmental HAP were reported by OSWRO facilities: POM, hydrogen 
chloride and hydrogen fluoride. For POM, none of the individual modeled 
concentrations for any facility in the source category exceeded any of 
the ecological benchmarks (either the LOAEL or NOAEL). For the acid 
gases HCl and HF, the average modeled concentration of these chemicals 
around each facility (i.e., the average concentration of all off-
facility-site data points in the modeling domain) did not exceed any 
ecological benchmarks. In addition, each individual modeled 
concentration of hydrogen chloride and hydrogen fluoride (i.e., each 
off-facility-site data point in the modeling domain) was below the 
ecological benchmarks for all facilities.
4. Facility-wide Inhalation Risk Assessment Results
    Table 3 displays the results of the facility-wide risk assessment. 
This assessment is based on actual emission levels. For detailed 
facility-specific results, see Appendix 5 of the Draft Residual Risk 
Assessment for the Off-Site Waste and Recovery Operations Source 
Category in the docket for this proposed rule.

   Table 3--Off-Site Waste and Recovery Operations Facility-Wide Risk
                           Assessment Results
------------------------------------------------------------------------
 
------------------------------------------------------------------------
Number of facilities analyzed........................                 38
Cancer Risk:
    Estimated maximum facility-wide individual cancer                200
     risk (in 1 million).............................
    Number of facilities with estimated facility-wide                  1
     individual cancer risk of 100-in-1 million or
     more............................................
    Number of facilities at which the OSWRO source                     0
     category contributes 50 percent or more to the
     facility-wide individual cancer risks of 100-in-
     1 million or more...............................
    Number of facilities with estimated facility-wide                 17
     individual cancer risk of 1-in-1 million or more
    Number of facilities at which the OSWRO source                     7
     category contributes 50 percent or more to the
     facility-wide individual cancer risk of 1-in-1
     million or more.................................
Chronic Non-cancer Risk:
    Maximum facility-wide chronic non-cancer TOSHI...                  4
    Number of facilities with facility-wide maximum                    2
     non-cancer TOSHI greater than 1.................
    Number of facilities at which the OSWRO source                     0
     category contributes 50 percent or more to the
     facility-wide maximum non-cancer TOSHI of 1 or
     more............................................
------------------------------------------------------------------------


[[Page 37868]]

    The facility-wide MIR and TOSHI are based on actual emissions from 
all emissions sources at the identified OSWRO facilities. The results 
indicate that 17 facilities have a facility-wide cancer MIR greater 
than or equal to 1-in-1 million and one facility has a facility-wide 
cancer MIR greater than or equal to 100-in-1 million. The maximum 
facility-wide MIR is 200-in-1 million due to emissions of beryllium 
compounds from the cement manufacturing processes at the facility site, 
with emission points from the OSWRO production source category 
contributing less than 1 percent of the maximum facility-wide risk. The 
results indicate that two facilities have a facility-wide non-cancer 
TOSHI greater than or equal to 1. The maximum facility-wide TOSHI is 4, 
and this TOSHI occurs at two facilities. At one of these facilities, 
the TOSHI is driven mainly by emissions of beryllium compounds from the 
same cement manufacturing processes mentioned above. The TOSHI at the 
other facility is driven mainly by emissions of chlorine from 
industrial inorganic chemical manufacturing processes and synthetic 
organic chemical manufacturing processes at the facility site. In each 
instance, the OSWRO production source category contributes less than 1 
percent to the facility-wide TOSHI. The focus of this analysis is the 
OSWRO source category and its low relative contribution to facility-
wide risk. The maximum facility-wide MIR and TOSHI values presented 
here are the result of a screening analysis for the other source 
categories located at common facility sites. The screening analysis 
requires further refinement and takes place during the RTR review for 
those source categories. We anticipate reductions of HAP from the 
cement manufacturing processes due to the implementation of the 
recently promulgated MACT standard, with a compliance date of September 
9, 2015, and the upcoming RTR review, with a consent decree deadline of 
June 15, 2017 for proposal and June 15, 2018 for promulgation. We may 
consider options for achieving further reduction of HAP from the 
inorganic chemical and synthetic organic chemical manufacturing 
processes in future reviews for those source categories.
5. What demographic groups might benefit from this regulation?
    To determine whether or not to conduct a demographics analysis, 
which is an assessment of risks to individual demographic groups, we 
look at a combination of factors including the MIR, non-cancer TOSHI, 
population around the facilities in the source category, and other 
relevant factors. Actual emissions from the OSWRO source category 
result in no individuals being exposed to cancer risk greater than 9-
in-1 million or a non-cancer TOSHI greater than 1. In addition, we 
estimate the cancer incidence for the source category to be 0.02 cases 
per year. Therefore, we did not conduct an assessment of risks to 
individual demographic groups for this proposed rule. However, we did 
conduct a proximity analysis, which identifies any overrepresentation 
of minority, low income or indigenous populations near facilities in 
the source category. The results of this analysis are presented in the 
section of this preamble entitled ``Executive Order 12898: Federal 
Actions to Address Environmental Justice in Minority Populations and 
Low-Income Populations.''

B. What are our proposed decisions regarding risk acceptability, ample 
margin of safety and adverse environmental effects?

1. Risk Acceptability
    As discussed in sections II.A and III.B of this preamble, we weigh 
all health risk factors in our risk acceptability determination, 
including the cancer MIR; the number of persons in various cancer and 
non-cancer risk ranges; cancer incidence; the maximum non-cancer TOSHI; 
the maximum acute non-cancer HQ; the extent of non-cancer risks; the 
potential for adverse environmental effects; the distribution of cancer 
and non-cancer risks in the exposed population; and risk estimation 
uncertainties (54 FR 38044, September 14, 1989).
    For the OSWRO source category, the risk analysis we performed 
indicates that the cancer risks to the individual most exposed could be 
up to 9-in-1 million due to actual emissions and up to 20-in-1 million 
due to MACT-allowable emissions. These risks are considerably less than 
100-in-1 million, which is the presumptive upper limit of acceptable 
risk. The risk analysis also shows relatively low cancer incidence 
(0.02 cases per year), as well as no appreciable risk of deleterious 
chronic or acute non-cancer health effects. In addition, the risk 
assessment indicates no significant potential multipathway health 
effects.
    While our analysis of facility-wide risks shows one facility with a 
maximum facility-wide cancer risk of 100-in-1 million or greater and 
two facilities with a maximum chronic non-cancer TOSHI greater than 1, 
it also shows that OSWRO operations did not drive these risks. In fact, 
OSWRO operations contribute less than 1 percent to the cancer MIR and 
less than 1 percent to the non-cancer TOSHI).
    Considering all of the health risk information and factors 
discussed above, including the uncertainties discussed in section 
III.A.8 of this preamble, we propose that the risks from the OSWRO 
source category are acceptable.
2. Ample Margin of Safety Analyses and Proposed Controls
    Although we are proposing that the risks from the OSWRO source 
category are acceptable, risk estimates for 210,000 individuals in the 
exposed population are above 1-in-1 million based on actual emissions. 
We recognize that our risk analysis indicates that the cancer risks to 
the individual most exposed are well within EPA's acceptable range 
(i.e., up to 9-in-1 million due to actual emissions and up to 20-in-1 
million due to MACT-allowable emissions). However, as stated in the 
Benzene NESHAP, in protecting public health with an ample margin of 
safety, ``EPA strives to provide maximum feasible protection against 
risks to health from HAP,'' considering available health information, 
the incremental risk reduction associated with more stringent 
standards, technological feasibility, and other factors, such as costs 
and economic impacts of controls. 54 FR at 38044-38045. Consequently, 
in this analysis, we investigated available emissions control options 
that might reduce the risk associated with emissions from the source 
category. We considered this information along with all of the health 
risks and other health information considered in determining risk 
acceptability. As explained below, we are proposing additional control 
requirements for equipment leaks and certain tanks because considering 
costs and other factors, we have determined that these additional 
controls are capable of further reducing risks to the individual most 
exposed, and thus, they provide an ample margin of safety.
    For the OSWRO source category, we did not identify any options that 
would reduce HAP emissions from containers, surface impoundments, oil-
water separators, organic-water separators or transfer systems beyond 
what is currently required in the rule. For process vents, tanks and 
equipment leaks, we identified additional control options, which are 
described below.
    For 19 of the 38 facilities included in the OSWRO risk analysis, 
the available data (see discussion of emissions data in section III.A 
of this preamble) did not,

[[Page 37869]]

in general, attribute OSWRO emissions to specific emission sources. For 
example, the NEI data for many of these facilities grouped emissions 
under source classification codes (SCC) for non-specific processes, 
such as 39999999--Miscellaneous Industrial Processes. For these 
facilities, we lack information as to which processes and emission 
point types are contributing to the risk estimates developed in the 
risk assessment. In contrast, CAA section 114 response data for the 
other 19 facilities were available, and the emissions data for these 
facilities were attributed to specific emission point types. However, 
the maximum cancer MIR and noncancer TOSHI values for the OSWRO source 
category are attributed to a facility for which only NEI data are 
available and for which we lack information regarding the processes and 
emission point types that contribute to these maximum risk values. 
Because we were unable to precisely determine the magnitude of HAP 
emissions from specific process types and how those emissions relate to 
the risk estimates, we conservatively assumed that the type of 
equipment under investigation was responsible for the maximum risks. 
For example, in our assessment of process vents, we assumed the maximum 
risks for the OSWRO source category were due to process vents, and then 
we evaluated how further controls might reduce this risk. While these 
assumptions may introduce some uncertainty regarding the risk 
reductions that would be achieved for each equipment type, we are 
presenting our analysis using the best information available. As noted 
in section VI of this preamble, we are requesting commenters to provide 
any site-specific emissions or other data that would enable us to 
better characterize the maximum risks and the risk reductions from the 
proposed control options for the OSWRO source category.
    In the ample margin of safety analysis, factors related to the 
appropriate level of control are considered, including the costs and 
economic impacts of the controls. For the OSWRO source category, the 
control options identified to reduce risks are the same as those 
identified in the technology review. As such, we relied on the control 
cost estimates and estimates of control cost effectiveness derived from 
the technology review analyses in our ample margin of safety 
determination. We believe that our ample margin of safety analysis is 
reasonable. However, we note that if we had data to more precisely 
assign HAP emissions to particular emission sources in the risk 
modeling file and if that data were to lead us to conclude that the 
MACT standards reflect an ample margin of safety, we are still 
proposing these same control options under the technology review 
because they are technologically applicable and cost effective for this 
source category based on our experience with similar emission sources 
emitting similar HAP at other chemical type facilities. We request 
comments on the proposed controls discussed below to provide an ample 
margin of safety for this source category.
    For process vents, as discussed in section IV.C of this preamble, 
we identified an emissions control option of requiring compliance with 
a 98 percent reduction rather than a 95 percent reduction in HAP 
emissions. To assess the maximum potential for risk reduction that 
could result from this process vent control option, we assumed that the 
maximum risks for the OSWRO source category are due to emissions from a 
process vent with emissions controlled at 95 percent. In this scenario, 
we estimate the HAP reduction resulting from compliance with a 98 
percent reduction would be 10 tpy from the current emissions level, 
with a cost effectiveness of $350,000/ton HAP reduction. We estimate 
this option would reduce the MIR at the MACT-allowable emissions level 
for the source category from 20-in-1 million to 8-in-1 million and 
reduce the maximum chronic non-cancer TOSHI from 1 to 0.4. Considering 
all of the health risks and other health information considered in our 
determination of risk acceptability, the potential for reductions in 
HAP emissions and risk, the uncertainty associated with the estimated 
potential risk reductions and the costs associated with this option, we 
are proposing that no additional HAP emissions controls for OSWRO 
process vents are necessary to provide an ample margin of safety to 
protect public health.
    For tanks, as discussed in section IV.C of this preamble, we 
identified two emissions control options. Option 1 requires Level 2 
control of emissions for additional tanks containing liquids with lower 
vapor pressures. Option 2 requires compliance with a 98 percent 
reduction rather than a 95 percent reduction in HAP emissions from 
tanks. As discussed above for process vents, to assess the maximum 
potential for risk reduction that could result from these two tank 
control options, we have assumed that the maximum risks for the OSWRO 
source category are due to emissions from tanks. For Option 1, we have 
assumed that the maximum risks are due to tanks that are not currently 
subject to Level 2 controls, which require a 95 percent reduction in 
emissions. In this scenario, we estimate the HAP reduction resulting 
from compliance with the control of additional tanks would be 73 tpy 
from the current emissions level, with a cost effectiveness of $300/ton 
HAP reduction. We estimate this option would reduce the MIR at the 
MACT-allowable emissions level for the source category from 20-in-1 
million to 1-in-1 million and reduce the maximum chronic non-cancer 
TOSHI from 1 to 0.05. Under Option 2, we estimate the HAP reduction 
incremental to Option 1 would be approximately 22 tpy, with a cost 
effectiveness of $13,000/ton HAP reduction and a cost effectiveness 
incremental to Option 1 of $56,000/ton HAP reduction. We estimate this 
option would reduce the MIR at the MACT-allowable emissions level 
incremental to Option 1 for the source category from 1-in-1 million to 
0.4-in-1 million and reduce the maximum chronic non-cancer TOSHI from 
0.05 to 0.02. Considering all of the health risks and other health 
information considered in our determination of risk acceptability, the 
potential risk reductions and the costs associated with Option 1, we 
are proposing to require this additional level of control to provide an 
ample margin of safety. Considering all of the health risks and other 
health information considered in our determination of risk 
acceptability, the potential for reductions in risk, the uncertainty 
associated with the estimated potential risk reductions and the costs 
associated with Option 2, we are proposing that the additional HAP 
emissions controls for OSWRO tanks under Option 2 are not necessary to 
provide an ample margin of safety to protect public health. In 
addition, as discussed further in preamble section IV.C, we are also 
proposing the Option 1 additional control level as a result of the 
technology review.
    For equipment leaks, as discussed in section IV.C of this preamble, 
we identified two emission control options: Option 1 requires 
compliance with 40 CFR part 63, subpart H, rather than 40 CFR part 61, 
subpart V, without the connector leak detection and repair (LDAR) 
requirements of subpart H; Option 2 requires the same as Option 1 but 
includes the connector LDAR requirement of subpart H. As discussed 
above for tanks, to assess the maximum potential for risk reduction 
that could result from these equipment leaks control options, we 
assumed that the maximum risks for the OSWRO source category are due to 
emissions from equipment leaks. We also assumed that

[[Page 37870]]

since emissions from equipment leaks are estimated to be the same at 
actual and MACT-allowable emission levels, the risks due to equipment 
leaks at the MACT-allowable level are the same as risks due to 
equipment leaks at actual emissions levels. We additionally assumed, 
based on our analysis of estimated baseline equipment leak 
emissions,\24\ that half of the equipment leak emissions causing the 
maximum risks are from non-connector components (i.e. pumps and 
valves), and the other half are from connectors. Given these 
assumptions, under Option 1, we estimate the HAP reduction resulting 
from compliance with subpart H without the subpart H connector 
monitoring requirements would be 69 tpy from the baseline actual 
emissions level, with a cost effectiveness of $1,000/ton HAP reduction. 
We estimate this option would reduce the MIR at the MACT-allowable 
emissions level for the equipment leaks at the source category from 9-
in-1 million to 7-in-1 million and reduce the maximum chronic non-
cancer TOSHI from 0.6 to 0.5. Under Option 2, we estimate the 
incremental HAP reduction resulting from compliance with subpart H 
including the subpart H connector monitoring requirements would be 70 
tpy more than Option 1, with an overall cost effectiveness of $4,000/
ton HAP reduction and a cost effectiveness incremental to Option 1 of 
$7,000/ton HAP reduction. We estimate this option would reduce the MIR 
at the MACT-allowable emissions level incremental to Option 1 for the 
equipment leaks at the source category from 7-in-1 million to 5-in-1 
million and reduce the maximum chronic non-cancer TOSHI from 0.5 to 
0.3. We note, as discussed in preamble section IV.C, we are proposing 
the additional control level of Option 2 as a result of the technology 
review. Considering the health risks and other health information 
evaluated in our determination of risk acceptability, that some risk 
reduction occurs with Option 2, and the costs associated with Option 2 
are reasonable, we are proposing to require this additional level of 
control to provide an ample margin of safety.
---------------------------------------------------------------------------

    \24\ See Technology Review and Cost Impacts for the Proposed 
Amendments to the Off-Site Waste and Recovery Operations Source 
Category, which is available in the docket for this action.
---------------------------------------------------------------------------

    In accordance with the approach established in the Benzene NESHAP, 
the EPA weighed all health risk measures and information considered in 
the risk acceptability determination, along with the costs of emissions 
controls, technological feasibility, uncertainties and other relevant 
factors in making our ample margin of safety determination. Considering 
the health risk information, the potential risk reductions and the 
reasonable cost effectiveness of certain control options identified for 
tanks and equipment leaks, we propose that the standards for the OSWRO 
source category be revised to include the proposed control Option 1 for 
tanks and the proposed control Option 2 for equipment leaks to provide 
an ample margin of safety to protect public health.
3. Adverse Environmental Effects
    We conducted an environmental risk screening assessment for the 
OSWRO source category for POM, HCl and HF. For POM, none of the 
individual modeled Tier I concentrations for any facility in the source 
category exceeded any of the ecological benchmarks (either the LOAEL or 
NOAEL). For HF and HCl, the average modeled concentration around each 
facility (i.e., the average concentration of all off-site data points 
in the modeling domain) did not exceed any ecological benchmark. Based 
on these results, we are proposing that it is not necessary to set a 
more stringent standard to prevent such an adverse environmental 
effect, taking into consideration costs, energy, safety, and other 
relevant factors.

C. What are the results of the technology review and our proposed 
decisions?

    As described in section III.C of this preamble, our technology 
review focused on identifying developments in practices, processes and 
control technologies for the emission sources in the OSWRO production 
source category. To identify such developments since the MACT standards 
were developed, we consulted the EPA's RACT/BACT/LAER Clearinghouse, 
reviewed subsequent regulatory development efforts and reviewed data 
from the 2013 CAA Section 114 survey of OSWRO facilities. For the OSWRO 
source category, we did not identify any developments in practices, 
processes or control technologies for containers, surface impoundments, 
oil-water separators, organic-water separators or transfer systems 
beyond what is currently required in the rule. For process vents, tanks 
and equipment leaks, we identified additional control options, and the 
following sections summarize the results of our technology review for 
these emissions sources.
    To perform the technology review, we needed information that was 
not included in the RTR emissions dataset used for modeling OSWRO 
risks. Therefore, to evaluate the costs and cost-effectiveness of 
various control options, we used a model plant approach. The model 
plant approach we used resulted in different baseline emission 
estimates than those included in the risk modeling dataset. More 
information concerning our technology review and model plant approach 
can be found in the memorandum titled, Technology Review and Cost 
Impacts for the Proposed Amendments to the Off-Site Waste and Recovery 
Operations Source Category, which is available in the docket for this 
action.
1. Tanks
    For tanks at existing affected sources, we identified two potential 
developments in practices and control techniques. The current OSWRO 
MACT requirements at 40 CFR 63.685(b)(1) for tanks at an existing 
affected source depend on the capacity of the tank and the vapor 
pressure of the material being stored. ``Level 2'' control is required 
for: (1) Tanks with capacities greater than or equal to 75 cubic meters 
(m\3\), but less than 151 m\3\ and a vapor pressure of 27.6 kilopascals 
(kPa) or greater and (2) tanks with capacities greater than or equal to 
151 m\3\ and a vapor pressure of 5.2 kPa or greater. ``Level 2'' 
control essentially requires one of five options: (1) A fixed roof tank 
equipped with an internal floating roof; (2) a fixed roof tank equipped 
with an external floating roof; (3) a tank with a vapor-tight cover and 
vented through a closed-vent system to a control device that has an 
efficiency of 95 percent or more; (4) a pressure tank; or (5) a tank 
inside a permanent total enclosure (PTE) that is vented through a 
closed-vent system to an enclosed combustion control device. Tanks of 
any capacity (effectively those less than 75 m\3\) with a vapor 
pressure of 76.6 kPa or greater are required to use one of the options 
listed above for Level 2 control, except that fixed roof tanks with 
either an internal or an external floating roof cannot be used. For 
tanks with capacities and vapor pressures less than those stated above, 
``Level 1'' control is required. ``Level 1'' control generally requires 
a fixed roof with closure devices.
    We evaluated two control options that would change the tank 
requirements if adopted. Option 1 would lower the vapor pressure 
threshold above which Level 2 controls would be required for some 
tanks. Option 2 would revise the vapor pressure threshold as in Option 
1 and increase the required control efficiency from the current 95 
percent to a 98 percent emissions reduction for all tanks required to 
use Level 2 controls. Through the review of air toxics MACT standards 
developed subsequent to the

[[Page 37871]]

OSWRO MACT standards, we noted that several other MACT standards refer 
to the Hazardous Organic NESHAP (HON) for their storage tank 
requirements. We evaluated revising the applicability of the OSWRO 
existing source requirements to use the same thresholds for Level 2 
control as the thresholds for control required by the HON. As shown in 
Table 4, Option 1 would require Level 2 emissions control for tanks 
with capacities greater than or equal to 75 m\3\, but less than 151 
m\3\, if the vapor pressure of the stored material is 13 kPa or 
greater, instead of 27.6 kPa or greater as required by the current MACT 
standard. No other tank size or vapor thresholds would be changed with 
Option 1. For tanks at new affected sources, the current OSWRO 
applicability thresholds are consistent with those required for the 
chemical industry under other NESHAP, including the HON, so no revised 
applicability requirements were evaluated for tanks located at new 
sources.
    Because available data for the source category indicate most OSWRO 
tanks currently have fixed-roofs with emissions routed through a closed 
vent system to a control device, under Option 2 we considered the 
impacts of requiring a higher control efficiency than currently 
required by the OSWRO MACT standard. While carbon adsorption and other 
control devices are assumed to have a control efficiency of 95 percent, 
other technologies are capable of achieving greater emissions control, 
such as thermal incinerators. Several of these devices have been 
demonstrated to achieve a control efficiency of 98 percent or greater. 
Under Option 2, we considered the impacts of requiring a 98 percent 
emissions reduction for tanks meeting the lowered vapor pressure 
threshold under Option 1, and all other tanks required to use Level 2 
emission controls, assuming a recuperative thermal oxidizer (RCO) would 
be used to attain this increased level of control.
    Table 5 presents the emission reductions and costs of the two 
options considered for tanks at existing affected sources in the OSWRO 
source category under the technology review. For Option 1, data 
collected through our CAA section 114 questionnaire indicate that only 
some facilities have tanks in the size and vapor pressure range 
considered for this option, and based on these data we estimate that 
approximately three OSWRO facilities have tanks that would require 
additional control under Option 1. As seen in Table 5, for Option 1, we 
estimate the capital costs to be approximately $76,000, and the total 
annualized costs are estimated to be approximately $21,000. The 
estimated HAP emissions reduction is approximately 73 tpy, and the cost 
effectiveness is approximately $300/ton. For Option 2, data collected 
through our CAA section 114 questionnaire indicate that only some 
facilities have tanks that currently require Level 2 emissions controls 
or that would require Level 2 control with the revised vapor pressure 
threshold of Option 1, and based on this data we estimate that 
approximately 10 OSWRO facilities have tanks that would require 
additional control under Option 2. We estimate the capital costs to be 
approximately $2.8 million, and the total annualized costs are 
estimated to be approximately $1.3 million. The estimated HAP emissions 
reduction incremental to Option 1 is approximately 22 tpy, and the 
incremental cost effectiveness between Option 1 and Option 2 is 
approximately $56,000/ton.

                Table 4--Requirements of Tank Options 1 and 2 for Existing OSWRO Affected Sources
----------------------------------------------------------------------------------------------------------------
     Options 1 and 2 applicability thresholds
---------------------------------------------------  Then control
                                       And vapor       level for    Option 1 Requirements  Option 2 Requirements
         If size (m\3\) is          pressure (kPa)   options 1 and
                                          is               2
----------------------------------------------------------------------------------------------------------------
<75...............................           <76.6               1                   Fixed roof.
                                   -----------------------------------------------------------------------------
                                            >=76.6           \a\ 2  95% control \b\......  98% control.\b\
----------------------------------------------------------------------------------------------------------------
75 <= capacity < 151..............           <13.1               1                   Fixed roof.
                                   -----------------------------------------------------------------------------
                                            >=13.1               2  95% control \c\......  98% control.\c\
----------------------------------------------------------------------------------------------------------------
151 <= capacity...................            <5.2               1                   Fixed roof.
                                   -----------------------------------------------------------------------------
                                             >=5.2               2  95% control \c\......  98% control.\c\
----------------------------------------------------------------------------------------------------------------
\a\ Except that fixed roof tanks equipped with an internal floating roof and tanks equipped with an external
  floating roof shall not be used.
\b\ Control efficiency would apply to tanks vented through a closed vent system to a control device and tanks
  inside a PTE that are vented to a combustion control device; use of a pressure tank would still be an
  available control option.
\c\ Control efficiency would apply to tanks vented through a closed vent system to a control device and tanks
  inside a PTE that are vented to a combustion control device; use of an internal or external floating roof or a
  pressure tank would still be available control options.


                           Table 5--Nationwide Emissions Reductions and Costs of Control Options for Tanks at OSWRO Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                            Cost
                                                                  HAP emissions                      Annual cost ($/    effectiveness   Incremental cost
                      Regulatory options                         reduction (tpy)  Capital cost ($)         yr)           ($/ton HAP     effectiveness ($/
                                                                                                                          removed)      ton HAP removed)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Option 1......................................................              72.8            76,000            21,000               300  ................
Option 2......................................................              95.0         2,800,000         1,300,000            13,000            56,000
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on our analysis, the costs of Option 1 are reasonable, given 
the level of HAP emissions reduction that would be achieved with this 
control option. The costs of Option 2 do not appear reasonable, given 
the level of HAP emissions reduction it would achieve. Therefore, as a 
result of the technology review, we are proposing to revise the

[[Page 37872]]

OSWRO MACT standards in accordance with Option 1, i.e., to require 
Level 2 controls for tanks at existing affected sources with capacities 
greater than or equal to 75 m\3\, but less than 151 m\3\, and a vapor 
pressure of 13.1 kPa or greater. We solicit comment on our assessment 
and conclusions regarding all aspects of both options. As noted in 
section IV.B.2, we are concurrently proposing to revise the OSWRO MACT 
standards for existing affected sources to require Level 2 controls for 
these tanks under section 112(f)(2) of the CAA to provide an ample 
margin of safety to protect public health.
2. Equipment Leaks
    The OSWRO MACT standards at 40 CFR 63.691 currently require 
compliance with either 40 CFR part 61, subpart V, or 40 CFR part 63, 
subpart H, to control emissions from equipment leaks at existing and 
new affected sources. While many provisions of these two rules are the 
same or similar, subpart H requires the use of a more stringent leak 
definition for valves in gas and vapor service and in light liquid 
service, pumps in light liquid service, and connectors. Specifically, 
subpart H lowers the leak definition for valves from 10,000 ppm (in 
subpart V) to 500 ppm, lowers the leak definition for pump seals from 
10,000 ppm (in subpart V) to 1,000 ppm, and requires periodic 
instrument monitoring of connectors with a leak definition of 500 ppm, 
as opposed to instrument monitoring only being required if a potential 
leak is detected by visual, audible, olfactory, or other detection 
method (in subpart V). We identified the more stringent leak 
definitions of subpart H as a development in practices, processes or 
control technologies.
    Assuming conservatively that each of the OSWRO facilities currently 
comply with subpart V and do not already comply with subpart H, we 
analyzed the costs and emission reductions of two options: Option 1--
switching from a subpart V LDAR program to a subpart H LDAR program, 
without the subpart H connector monitoring requirements; Option 2--
switching from a subpart V LDAR program to a subpart H LDAR program, 
with the subpart H connector monitoring requirements. The estimated 
costs and emissions reductions associated with these two options for 
the OSWRO source category are shown in Table 6. For Option 1 (subpart H 
without connector monitoring), we estimated the capital costs to be 
approximately $320,000, and the total annualized costs are estimated to 
be approximately $67,000. The estimated HAP emissions reduction is 
approximately 69 tpy, and the cost effectiveness is approximately 
$1,000/ton. For Option 2 (subpart H with connector monitoring), we 
estimated the capital costs to be approximately $1,900,000, and the 
total annualized costs are estimated to be approximately $530,000. The 
estimated HAP emissions reduction is approximately 138 tpy, and the 
cost effectiveness is approximately $4,000/ton. The incremental cost 
effectiveness between Option 1 and Option 2 is approximately $7,000.

                                           Table 6--OSWRO Equipment Leak Options Emission Reductions and Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                            Cost        Incremental cost
                    Regulatory alternatives                       HAP Emissions   Capital cost ($)   Annual cost ($/  effectiveness ($/ effectiveness ($/
                                                                 reduction (tpy)                           yr)        ton HAP removed)  ton HAP removed)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Option 1: Subpart H, no connector monitoring..................              68.5           320,000            67,000             1,000  ................
Option 2: Subpart H with connector monitoring.................             138.1         1,900,000           530,000             4,000             7,000
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on our analysis, the costs of Option 2, which includes all of 
the requirements of Option 1, are reasonable, given the level of HAP 
emissions reduction that would be achieved with this control option. 
Therefore, as a result of the technology review, we are proposing to 
revise the OSWRO MACT standards, in accordance with Option 2, to 
require existing and new affected sources to comply with subpart H 
rather than subpart V, including the subpart H requirements for 
connectors in gas and vapor service and in light liquid service. As 
noted in section IV.B.2, we are concurrently proposing to revise the 
OSWRO MACT standards for existing and new affected sources to require 
compliance with subpart H rather than subpart V, including the subpart 
H requirements for connectors in gas and vapor service and in light 
liquid service under section 112(f)(2) of the CAA to provide an ample 
margin of safety to protect public health. We solicit comment on our 
assessment and conclusions regarding all aspects of both options.
3. Process Vents
    The current OSWRO MACT standards at 40 CFR 63.690 require emissions 
from process vents at existing and new affected sources to be routed 
through a closed vent system to a control device achieving at least 95 
percent control. As discussed above for tanks, while carbon adsorption 
and other control devices are assumed to have a control efficiency of 
95 percent, other technologies are capable of achieving greater 
emissions control, such as thermal incinerators. Several of these 
devices have been demonstrated to achieve a control efficiency of 98 
percent or greater. Based on the combination of reported control 
efficiencies for these devices and known application to low 
concentration organic vapor gas streams, we investigated the use of a 
regenerative thermal oxidizer with a control efficiency of 98 percent 
as a potential control option.
    Table 7 presents the emission reductions and costs of the 98 
percent control options considered for process vents at existing 
affected sources in the OSWRO source category under the technology 
review. Data collected through our CAA section 114 questionnaire 
indicate that only some facilities have process vents, and based on 
these data we estimate that approximately eight OSWRO facilities have 
process vents that would require additional control to reduce emissions 
by 98 percent. We estimated the capital costs of complying with an 
increase from 95 to 98 percent HAP control for process vents to be 
approximately $9.8 million, and the total annualized costs are 
estimated to be approximately $3.3 million. The estimated HAP emissions 
reduction is approximately 10 tpy, and the cost effectiveness is 
approximately $350,000/ton of HAP emission reduction.

[[Page 37873]]



                                   Table 7--OSWRO Process Vent Option Impacts
----------------------------------------------------------------------------------------------------------------
                                                                                                      Cost
          Regulatory option             HAP emissions     Capital cost ($)   Annual cost ($/   effectiveness ($/
                                       reduction (tpy)                             yr)          ton HAP removed)
----------------------------------------------------------------------------------------------------------------
98 percent control..................               9.6          9,800,000          3,300,000            350,000
----------------------------------------------------------------------------------------------------------------

    Based on our estimate of costs and HAP reduction, we do not 
consider increasing the emission reduction to 98 percent to be 
reasonable, and we are not proposing to revise the OSWRO MACT standards 
for process vents pursuant to CAA section 112(d)(6) to require this 
level of emissions control. We solicit comment on our analysis, and as 
noted in section IV.B.2, we also solicit comments regarding the 
emissions controls proposed as a result of this technology review, 
given the uncertainty in the emissions estimates and the potential 
impact on the estimates of cost effectiveness.

D. What other actions are we proposing?

    We are also proposing revisions to the startup, shutdown and 
malfunction (SSM) provisions of the MACT rule to ensure that they are 
consistent with the court decision in Sierra Club v. EPA, 551 F. 3d 
1019 (D.C. Cir. 2008), which vacated two provisions that exempted 
sources from the requirement to comply with otherwise applicable 
section 112(d) emission standards during periods of SSM. Second, we are 
proposing to require electronic reporting of emissions test results. 
Third, we are proposing to revise the routine maintenance provisions 
and limit those provisions only to tanks routing emissions to a control 
device. Fourth, we are proposing to clarify what ``seal the open end at 
all times'' means for open-ended lines and valves in the equipment leak 
provisions of the rule. Fifth, we are proposing that emissions of HAP 
from safety devices and closure devices directly to the atmosphere are 
prohibited, and we are proposing to require monitoring of pressure 
releases from pressure relief devices (PRDs) that release directly to 
the atmosphere. Sixth, we are proposing minor clarifications to the 
sample run times and sample site location required for some performance 
test methods, and we are proposing to allow the use of a different 
performance test method in two cases. Seventh, we are proposing various 
minor clarifications and corrections to the rule. In addition to these 
proposed revisions, we are seeking comments containing information 
regarding flares used by facilities in this source category. We present 
details and the rationales for the proposed changes in the following 
sections.
1. Startup, Shutdown and Malfunctions
a. Background
    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008), the United States Court of Appeals for the District of 
Columbia Circuit vacated portions of two provisions in the EPA's CAA 
section 112 regulations governing the emissions of HAP during periods 
of SSM. Specifically, the Court vacated the SSM exemption contained in 
40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1) holding that under section 
302(k) of the CAA, emissions standards or limitations must be 
continuous in nature and that the SSM exemption violates the CAA's 
requirement that some section 112 standards apply continuously.
    We are proposing to eliminate the SSM exemption in the OSWRO 
NESHAP. Consistent with Sierra Club v. EPA, we are proposing standards 
in this rule that apply at all times. We are also proposing several 
revisions to Table 2 (the General Provisions Applicability Table) as is 
explained in more detail below. For example, we are proposing to 
eliminate the incorporation of the General Provisions' requirement that 
the source develop an SSM plan. We also are proposing to eliminate and 
revise certain recordkeeping and reporting requirements related to the 
SSM exemption as further described below.
    The EPA has attempted to eliminate provisions that are 
inappropriate, unnecessary, or redundant in the absence of the SSM 
exemption in this proposal. We are specifically seeking comment on 
whether we have successfully done so.
    In proposing the standards in this rule, the EPA has taken into 
account startup and shutdown periods and, for the reasons explained 
below, has not proposed alternate standards for those periods.
    Information on periods of startup and shutdown received from OSWRO 
facilities through the CAA section 114 questionnaire responses indicate 
that emissions during these periods are the same as during normal 
operations. The facilities do not process waste unless and until their 
control devices are operating to fully control emissions. Therefore, 
separate standards for periods of startup and shutdown are not 
necessary and are not being proposed. We solicit comment on our 
findings and conclusions regarding periods of startup and shutdown at 
OSWRO facilities.
    Periods of startup, normal operations, and shutdown are all 
predictable and routine aspects of a source's operations. However, by 
contrast, malfunction is defined as a ``sudden, infrequent, and not 
reasonably preventable failure of air pollution control and monitoring 
equipment, process equipment or a process to operate in a normal or 
usual manner * * *'' (40 CFR 63.2). The EPA has determined that CAA 
section 112 does not require that emissions that occur during periods 
of malfunction be factored into development of CAA section 112 
standards. Under section 112, emissions standards for new sources must 
be no less stringent than the level ``achieved'' by the best controlled 
similar source and for existing sources generally must be no less 
stringent than the average emission limitation ``achieved'' by the best 
performing 12 percent of sources in the category. There is nothing in 
section 112 that directs the EPA to consider malfunctions in 
determining the level ``achieved'' by the best performing sources when 
setting emission standards. As the DC Circuit has recognized, the 
phrase ``average emissions limitation achieved by the best performing 
12 percent of sources ``says nothing about how the performance of the 
best units is to be calculated.'' Nat'l Ass'n of Clean Water Agencies 
v. EPA, 734 F.3d 1115, 1141 (D.C. Cir. 2013). While the EPA accounts 
for variability in setting emissions standards, nothing in section 112 
requires the EPA to consider malfunctions as part of that analysis. A 
malfunction should not be treated in the same manner as the type of 
variation in performance that occurs during routine operations of a 
source. A malfunction is a failure of the source to perform in a 
``normal or usual manner'' and no statutory language compels the EPA to 
consider such events in setting standards based on ``best performers.''
    Further, accounting for malfunctions in setting emissions standards 
would be difficult, if not impossible, given the

[[Page 37874]]

myriad different types of malfunctions that can occur across all 
sources in the category and given the difficulties associated with 
predicting or accounting for the frequency, degree, and duration of 
various malfunctions that might occur. As such, the performance of 
units that are malfunctioning is not ``reasonably'' foreseeable. See, 
e.g., Sierra Club v. EPA, 167 F. 3d 658, 662 (D.C. Cir. 1999) (the EPA 
typically has wide latitude in determining the extent of data-gathering 
necessary to solve a problem. We generally defer to an agency's 
decision to proceed on the basis of imperfect scientific information, 
rather than to ``invest the resources to conduct the perfect study.''). 
See also Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) 
(``In the nature of things, no general limit, individual permit, or 
even any upset provision can anticipate all upset situations. After a 
certain point, the transgression of regulatory limits caused by 
`uncontrollable acts of third parties,' such as strikes, sabotage, 
operator intoxication or insanity, and a variety of other 
eventualities, must be a matter for the administrative exercise of 
case-by-case enforcement discretion, not for specification in advance 
by regulation.''). In addition, the goal of a ``best controlled or best 
performing source'' is to operate in such a way as to avoid 
malfunctions of the source and accounting for malfunctions could lead 
to standards that are significantly less stringent than levels that are 
achieved by a well-performing non-malfunctioning source. It is 
reasonable to interpret section 112 to avoid such a result. The EPA's 
approach to malfunctions is consistent with CAA section 112 and is a 
reasonable interpretation of the statute.
    In the event that a source fails to comply with the applicable CAA 
section 112(d) standards as a result of a malfunction event, the EPA 
would determine an appropriate response based on, among other things, 
the good faith efforts of the source to minimize emissions during 
malfunction periods, including preventative and corrective actions, as 
well as root cause analyses to ascertain and rectify excess emissions. 
The EPA would also consider whether the source's failure to comply with 
the CAA section 112(d) standard was, in fact, ``sudden, infrequent, not 
reasonably preventable'' and was not instead ``caused in part by poor 
maintenance or careless operation.'' 40 CFR 63.2 (definition of 
malfunction). Further, to the extent the EPA files an enforcement 
action against a source for violation of an emission standard, the 
source can raise any and all defenses in that enforcement action, and 
the federal district court will determine what, if any, relief is 
appropriate. The same is true for citizen enforcement actions. 
Similarly, the presiding officer in an administrative proceeding can 
consider any defense raised and determine whether administrative 
penalties are appropriate.
    In several prior rules, the EPA had included an affirmative defense 
to civil penalties for violations caused by malfunctions in an effort 
to create a system that incorporates some flexibility, recognizing that 
there is a tension, inherent in many types of air regulations, to 
ensure adequate compliance, while simultaneously recognizing that 
despite the most diligent of efforts, emission standards may be 
violated under circumstances entirely beyond the control of the source. 
Although the EPA recognized that its case-by-case enforcement 
discretion provides sufficient flexibility in these circumstances, it 
included the affirmative defense to provide a more formalized approach 
and more regulatory clarity. See Weyerhaeuser Co. v. Costle, 590 F.2d 
1011, 1057-58 (D.C. Cir. 1978) (holding that an informal case-by-case 
enforcement discretion approach is adequate); but see Marathon Oil Co. 
v. EPA, 564 F.2d 1253, 1272-73 (9th Cir. 1977) (requiring a more 
formalized approach to consideration of ``upsets beyond the control of 
the permit holder.''). Under the EPA's regulatory affirmative defense 
provisions, if a source could demonstrate in a judicial or 
administrative proceeding that it had met the requirements of the 
affirmative defense in the regulation, civil penalties would not be 
assessed. Recently, the United States Court of Appeals for the District 
of Columbia Circuit vacated such an affirmative defense in one of the 
EPA's section 112(d) regulations. NRDC v. EPA, No. 10-1371 (D.C. Cir. 
April 18, 2014) 2014 U.S. App. LEXIS 7281 (vacating affirmative defense 
provisions in a section 112(d) rule establishing emission standards for 
Portland cement kilns). The court found that the EPA lacked authority 
to establish an affirmative defense for private civil suits and held 
that under the CAA, the authority to determine civil penalty amounts 
lies exclusively with the courts, not the EPA. Specifically, the Court 
found: ``As the language of the statute makes clear, the courts 
determine, on a case-by-case basis, whether civil penalties are 
`appropriate.''' See NRDC, 2014 U.S. App. LEXIS 7281 at *21 (``[U]nder 
this statute, deciding whether penalties are `appropriate' in a given 
private civil suit is a job for the courts, not EPA.''). In light of 
NRDC, the EPA is not including a regulatory affirmative defense 
provision in this proposed rule. As explained above, if a source is 
unable to comply with emissions standards as a result of a malfunction, 
the EPA may use its case-by-case enforcement discretion to provide 
flexibility, as appropriate. Further, as the DC Circuit recognized, in 
an EPA or citizen enforcement action, the court has the discretion to 
consider any defense raised and determine whether penalties are 
appropriate. Cf. NRDC, 2014 U.S. App. LEXIS 7281 at *24. (arguments 
that violation were caused by unavoidable technology failure can be 
made to the courts in future civil cases when the issue arises). The 
same logic applies to EPA administrative enforcement actions.
b. Specific SSM-Related Proposed Changes
    To address the United States Court of Appeals for the District of 
Columbia Circuit vacatur of portions of the EPA's CAA section 112 
regulations governing the emissions of HAP during periods of SSM, we 
are proposing revisions and additions to certain provisions of the 
OSWRO rule. As described in detail below, we are proposing to revise 
the General Provisions applicability table (Table 2 to Subpart DD) in 
several of the references related to requirements that apply during 
periods of SSM. We are also proposing revisions related to the 
following provisions of the OSWRO rule: (1) The general duty to 
minimize emissions at all times; (2) the requirement for sources to 
comply with the emission limits in the rule at all times, with 
clarifications for what constitutes a deviation; (3) performance 
testing conditions requirements; (4) excused monitoring excursions 
provisions; and (5) malfunction recordkeeping and reporting 
requirements.
i. General Duty
    We are proposing to revise the General Provisions table (Table 2) 
entry for 40 CFR 63.6(e) by adding rows specifically for 40 CFR 
63.6(e)(1)(i), 63.6(e)(1)(ii), 63.6(e)(1)(iii), and 63.6(e)(3) and to 
include a ``no'' in the second column for the 40 CFR 63.6(e)(1)(i) 
entry. Section 63.6(e)(1)(i) describes the general duty to minimize 
emissions. Some of the language in that section is no longer necessary 
or appropriate in light of the elimination of the SSM exemption. We are 
proposing instead to add general duty regulatory text at 40 CFR 
63.683(e) that reflects the

[[Page 37875]]

general duty to minimize emissions while eliminating the reference to 
periods covered by an SSM exemption. The current language in 40 CFR 
63.6(e)(1)(i) characterizes what the general duty entails during 
periods of SSM. With the elimination of the SSM exemption, there is no 
need to differentiate between normal operations, startup and shutdown, 
and malfunction events in describing the general duty. Therefore the 
language the EPA is proposing for 40 CFR 63.683(e) does not include 
that language from 40 CFR 63.6(e)(1).
    We are also proposing to include a ``no'' in the second column for 
the newly added entry for 40 CFR 63.6(e)(1)(ii). Section 63.6(e)(1)(ii) 
imposes requirements that are not necessary with the elimination of the 
SSM exemption or are redundant with the general duty requirement being 
added at 63.683(e).
    The provisions of 40 CFR 63.6(e)(1)(iii) still apply, and we are 
keeping the ``yes'' in the second column for that section. For 40 CFR 
63.6(e)(2), we are proposing to include a ``no'' in the second column 
for that section because it is a reserved section in the General 
Provisions.
    We are also proposing to clarify in the applicability section of 40 
CFR 63.680(g)(1) and (2) that the emission limits of subpart DD apply 
at all times except when the affected source is not operating and that 
the owner or operator must not shut down items of equipment required or 
used for compliance with the requirements of subpart DD.
ii. SSM Plan
    We are also proposing to include a ``no'' in the second column for 
the newly added 40 CFR 63.6(e)(3) entry. Generally, this paragraph 
requires development of an SSM plan and specifies SSM recordkeeping and 
reporting requirements related to the SSM plan. As noted, the EPA is 
proposing to remove the SSM exemptions. Therefore, affected units will 
be subject to an emission standard during such events. The 
applicability of a standard during such events will ensure that sources 
have ample incentive to plan for and achieve compliance and thus the 
SSM plan requirements are no longer necessary.
iii. Compliance With Standards
    We are proposing to revise the General Provisions table (Table 2) 
entry for 40 CFR 63.6(f)(1) by changing the ``yes'' in column 2 to a 
``no.'' The current language of 40 CFR 63.6(f)(1) exempts sources from 
non-opacity standards during periods of SSM. As discussed above, the 
court in Sierra Club vacated the exemptions contained in this provision 
and held that the CAA requires that some section 112 standard apply 
continuously. Consistent with Sierra Club, the EPA is proposing to 
revise standards in this rule to apply at all times.
iv. Performance Testing
    We are proposing to revise the General Provisions table (Table 2) 
entry for 40 CFR 63.7(e)(1) by changing the ``yes'' in column 2 to a 
``no.'' Section 63.7(e)(1) describes performance testing requirements. 
The EPA is instead proposing to add a performance testing requirement 
at 40 CFR 63.694(l). The performance testing requirements we are 
proposing to add differ from the General Provisions performance testing 
provisions in several respects. The regulatory text does not include 
the language in 40 CFR 63.7(e)(1) that restated the SSM exemption. 
However, consistent with 40 CFR 63.7(e)(1), performance tests conducted 
under this subpart should be based on representative performance (i.e., 
performance based on normal operating conditions) of the affected 
source. The EPA is proposing to add language that requires the owner or 
operator to record the process information that is necessary to 
document operating conditions during the test and include in such 
record an explanation to support that such conditions represent normal 
operation. Section 63.7(e) requires that the owner or operator make 
available to the Administrator such records ``as may be necessary to 
determine the condition of the performance test'' upon request, but 
does not specifically require the information to be recorded. The 
regulatory text the EPA is proposing to add to this provision builds on 
that requirement and makes explicit the requirement to record the 
information.
v. Monitoring
    We are proposing to revise the General Provisions table (Table 2) 
entries for 40 CFR 63.8(c)(1)(i) and (iii) by changing the ``yes'' in 
column 2 to a ``no.'' The cross-references to the general duty and SSM 
plan requirements in those subparagraphs are not necessary in light of 
other requirements of 40 CFR 63.8 that require good air pollution 
control practices (40 CFR 63.8(c)(1)) and that set out the requirements 
of a quality control program for monitoring equipment (40 CFR 63.8(d)).
vi. Recordkeeping
    We are proposing to revise the General Provisions table (Table 2) 
entry for 40 CFR 63.10(b)(2)(i) by changing the ``yes'' in column 2 to 
a ``no.'' Section 63.10(b)(2)(i) describes the recordkeeping 
requirements during startup and shutdown. These recording provisions 
are no longer necessary because the EPA is proposing that recordkeeping 
and reporting applicable to normal operations will apply to startup and 
shutdown. In the absence of special provisions applicable to startup 
and shutdown, such as a startup and shutdown plan, there is no reason 
to retain additional recordkeeping for startup and shutdown periods.
    We are proposing to revise the General Provisions table (Table 2) 
entry for 40 CFR 63.10(b)(2)(ii) by changing the ``yes'' in column 2 to 
a ``no.'' Section 63.10(b)(2)(ii) describes the recordkeeping 
requirements during a malfunction. The EPA is proposing to add such 
requirements to 40 CFR 63.696(h). The regulatory text we are proposing 
to add differs from the General Provisions it is replacing in that the 
General Provisions require the creation and retention of a record of 
the occurrence and duration of each malfunction of process, air 
pollution control, and monitoring equipment. The EPA is proposing that 
this requirement apply to any failure to meet an applicable standard 
and is requiring that the source record the date, time, and duration of 
the failure rather than the ``occurrence.'' The EPA is also proposing 
to add to 40 CFR 63.696(h) a requirement that sources keep records that 
include a list of the affected source or equipment and actions taken to 
minimize emissions, an estimate of the volume of each regulated 
pollutant emitted over the standard for which the source failed to meet 
the standard, and a description of the method used to estimate the 
emissions. Examples of such methods would include product-loss 
calculations, mass balance calculations, measurements when available, 
or engineering judgment based on known process parameters. The EPA is 
proposing to require that sources keep records of this information to 
ensure that there is adequate information to allow the EPA to determine 
the severity of any failure to meet a standard, and to provide data 
that may document how the source met the general duty to minimize 
emissions when the source has failed to meet an applicable standard.
    We are proposing to revise the General Provisions table (Table 2) 
entry for 40 CFR 63.10(b)(2)(iv) by changing

[[Page 37876]]

the ``yes'' in column 2 to a ``no.'' When applicable, the provision 
requires sources to record actions taken during SSM events when actions 
were inconsistent with their SSM plan. The requirement is no longer 
appropriate because SSM plans will no longer be required. The 
requirement previously applicable under 40 CFR 63.10(b)(2)(iv)(B) to 
record actions to minimize emissions and record corrective actions is 
now applicable by reference to 40 CFR 63.696(h).
    We are proposing to revise the General Provisions table (Table 2) 
entry for 40 CFR 63.10(b)(2)(v) by changing the ``yes'' in column 2 to 
a ``no.'' When applicable, the provision requires sources to record 
actions taken during SSM events to show that actions taken were 
consistent with their SSM plan. The requirement is no longer 
appropriate because SSM plans will no longer be required.
vii. Reporting
    We are proposing to revise the General Provisions table (Table 2) 
entry for 40 CFR 63.10(d)(5)(i) by consolidating it with the entry for 
63.10(d)(5)(ii) and changing the ``yes'' in column 2 to ``no.'' Section 
63.10(d)(5)(i) describes the reporting requirements for startups, 
shutdowns, and malfunctions. To replace the General Provisions 
reporting requirements, the EPA is proposing to add reporting 
requirements to 40 CFR 63.697(b)(3). The replacement language differs 
from the General Provisions requirement in that it eliminates periodic 
SSM reports as a stand-alone report. We are proposing language that 
requires sources that fail to meet an applicable standard at any time 
to report the information concerning such events in the semi-annual 
summary report already required under this rule. We are proposing that 
the report must contain the number, date, time, duration, and the cause 
of such events (including unknown cause, if applicable), a list of the 
affected source or equipment, an estimate of the quantity of each 
regulated pollutant emitted over any emission limit, and a description 
of the method used to estimate the emissions.
    Examples of such methods would include product-loss calculations, 
mass balance calculations, measurements when available, or engineering 
judgment based on known process parameters. The EPA is proposing this 
requirement to ensure that there is adequate information to determine 
compliance, to allow the EPA to determine the severity of the failure 
to meet an applicable standard, and to provide data that may document 
how the source met the general duty to minimize emissions during a 
failure to meet an applicable standard.
    We will no longer require owners or operators to determine whether 
actions taken to correct a malfunction are consistent with an SSM plan, 
because plans would no longer be required. The proposed amendments 
therefore eliminate the cross reference to 40 CFR 63.10(d)(5)(i) that 
contains the description of the previously required SSM report format 
and submittal schedule from this section. These specifications are no 
longer necessary because the events will be reported in otherwise 
required reports with similar format and submittal requirements.
    We are proposing to revise the General Provisions table (Table 2) 
entry for 40 CFR 63.10(d)(5)(ii) by consolidating it with the entry for 
63.10(d)(5)(i) and changing the ``yes'' in column 2 to a ``no.'' 
Section 63.10(d)(5)(ii) describes an immediate report for startups, 
shutdown, and malfunctions when a source failed to meet an applicable 
standard but did not follow the SSM plan. We will no longer require 
owners and operators to report when actions taken during a startup, 
shutdown, or malfunction were not consistent with an SSM plan, because 
plans would no longer be required.
2. Electronic Reporting
    In this proposal, the EPA is describing a process to increase the 
ease and efficiency of performance test data submittal while improving 
data accessibility. Specifically, the EPA is proposing that owners and 
operators of OSWRO facilities submit electronic copies of required 
performance test reports by direct computer-to-computer electronic 
transfer using EPA-provided software. The direct computer-to-computer 
electronic transfer is accomplished through the EPA's Central Data 
Exchange (CDX) using the Compliance and Emissions Data Reporting 
Interface (CEDRI). The Central Data Exchange is EPA's portal for 
submittal of electronic data. The EPA-provided software is called the 
Electronic Reporting Tool (ERT) which is used to generate electronic 
reports of performance tests and evaluations. The ERT generates an 
electronic report package which will be submitted using the CEDRI. The 
submitted report package will be stored in the CDX archive (the 
official copy of record) and EPA's public database called WebFIRE. All 
stakeholders will have access to all reports and data in WebFIRE and 
accessing these reports and data will be very straightforward and easy 
(see the WebFIRE Report Search and Retrieval link at http://cfpub.epa.gov/webfire/index.cfm?action=fire.searchERTSubmission). A 
description and instructions for use of the ERT can be found at http://www.epa.gov/ttn/chief/ert/index.html and CEDRI can be accessed through 
the CDX Web site (www.epa.gov/cdx). A description of the WebFIRE 
database is available at: http://cfpub.epa.gov/oarweb/index.cfm?action=fire.main.
    The proposal to submit performance test data electronically to the 
EPA applies only to those performance tests conducted using test 
methods that are supported by the ERT. The ERT supports most of the 
commonly used EPA reference methods. A listing of the pollutants and 
test methods supported by the ERT is available at: http://www.epa.gov/ttn/chief/ert/index.html.
    We believe that industry would benefit from this proposed approach 
to electronic data submittal. Specifically, by using this approach, 
industry will save time in the performance test submittal process. 
Additionally, the standardized format that the ERT uses allows sources 
to create a more complete test report resulting in less time spent on 
data backfilling if a source failed to include all data elements 
required to be submitted. Also through this proposal industry may only 
need to submit a report once to meet the requirements of the applicable 
subpart because stakeholders can readily access these reports from the 
WebFIRE database. This also benefits industry by cutting back on 
recordkeeping costs as the performance test reports that are submitted 
to the EPA using CEDRI are no longer required to be retained in hard 
copy, thereby, reducing staff time needed to coordinate these records.
    Since the EPA will have performance test data in hand, we expect 
that there may be fewer or less substantial data collection requests in 
conjunction with prospective required residual risk assessments or 
technology reviews. This would result in a decrease in staff time 
needed to respond to data collection requests.
    State, local and tribal air pollution control agencies (S/L/Ts) may 
also benefit from having electronic versions of the reports they are 
now receiving. For example, S/L/Ts may be able to conduct a more 
streamlined and accurate review of electronic data submitted to them. 
For example, the ERT would allow for an electronic review process, 
rather than a manual data assessment, therefore, making review and 
evaluation of the source provided data and calculations easier and more 
efficient. In addition, the public stands to benefit from electronic

[[Page 37877]]

reporting of emissions data because the electronic data will be easier 
for the public to access. How the air emissions data are collected, 
accessed and reviewed will be more transparent for all stakeholders.
    One major advantage of the proposed submittal of performance test 
data through the ERT is a standardized method to compile and store much 
of the documentation required to be reported by this rule. The ERT 
clearly states what testing information would be required by the test 
method and has the ability to house additional data elements that might 
be required by a delegated authority.
    In addition the EPA must have performance test data to conduct 
effective reviews of CAA sections 111, 112 and 129 standards, as well 
as for many other purposes including compliance determinations, 
emission factor development and annual emission rate determinations. In 
conducting these required reviews, the EPA has found it ineffective and 
time consuming, not only for us, but also for regulatory agencies and 
source owners and operators, to locate, collect and submit performance 
test data. In recent years, though, stack testing firms have typically 
collected performance test data in electronic format, making it 
possible to move to an electronic data submittal system that would 
increase the ease and efficiency of data submittal and improve data 
accessibility.
    A common complaint heard from industry and regulators is that 
emission factors are outdated or not representative of a particular 
source category. With timely receipt and incorporation of data from 
most performance tests, the EPA would be able to ensure that emission 
factors, when updated, represent the most current range of operational 
practices. Finally, another benefit of the proposed data submittal to 
WebFIRE electronically is that these data would greatly improve the 
overall quality of existing and new emissions factors by supplementing 
the pool of emissions test data for establishing emissions factors.
    In summary, in addition to supporting regulation development, 
control strategy development and other air pollution control 
activities, having an electronic database populated with performance 
test data would save industry, state, local, tribal agencies and the 
EPA significant time, money and effort, while also improving the 
quality of emission inventories and air quality regulations.
3. Routine Maintenance
    40 CFR 63.693(b)(3)(i) of the OSWRO NESHAP allows for control 
devices to be bypassed to perform planned routine maintenance of the 
closed-vent system or control device in situations when the routine 
maintenance cannot be performed during periods that the emission point 
vented to the control device is shut down. The facility is allowed to 
bypass the control device for up to 240 hours per year.
    The routine maintenance provision was originally established in the 
Hazardous Organic NESHAP (HON) (see 40 CFR 63.119(e)(3)-(4); 57 FR 
62710, December 31, 1992 (proposed); 59 FR 19402, April 22, 1994 
(final)) for facilities that elected to use a closed vent system and 
control device to comply with the emission limitation requirements for 
tanks. We included the routine maintenance provision in the HON for 
tanks routing emissions to control devices because the estimated HAP 
emissions to degas the tank would be greater than the emissions that 
would result if the tank emitted directly to the atmosphere for a short 
period of time during routine maintenance of the control device.
    We intended for the OSWRO NESHAP to track the HON maintenance 
provisions, and as such, those provisions should have been limited to 
tanks. We have not identified a basis for applying the routine 
maintenance provisions in the OSWRO NESHAP to emission points other 
than tanks. Therefore, we are proposing to limit the provision to tanks 
routing emissions to a control device, consistent with the rationale 
provided in the HON. We request comment on this proposed revision.
4. Open-Ended Valves and Lines
    The OSWRO NESHAP at 40 CFR 63.691(b) requires an owner or operator 
to control emissions from equipment leaks according to the requirements 
of either 40 CFR part 61, subpart V or 40 CFR part 63, subpart H. For 
open-ended valves and lines, both subpart V in Sec.  61.242-6(a) and 
subpart H in Sec.  63.167(a) require that the open end be equipped with 
a cap, blind flange, plug, or second valve that shall ``seal the open 
end.'' However, ``seal'' is not defined in either subpart, leading to 
uncertainty for the owner or operator as to whether compliance is being 
achieved. Inspections under the EPA's Air Toxics LDAR initiative have 
provided evidence that while certain open-ended lines may be equipped 
with a cap, blind flange, plug or second valve, these are not providing 
a ``seal'' as the EPA interprets the term.\25\
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    \25\ See ``Region V OEL data for VV rulemaking'' available in 
the docket for this action.
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    In response to this uncertainty, we are proposing to amend 40 CFR 
63.691(a) to clarify what ``seal the open end'' means for open-ended 
valves and lines. This proposed clarification explains that, for the 
purpose of complying with the requirements of 40 CFR 63.167 of subpart 
H, open-ended valves and lines are ``sealed'' by the cap, blind flange, 
plug, or second valve instrument monitoring of the open-ended valve or 
line conducted according to Method 21 of 40 CFR part 60, appendix A 
indicates no readings of 500 ppm or greater.
    In addition, 40 CFR 63.167(d) of subpart H and 40 CFR 61.242-6(d) 
of subpart V exempt open-ended valves and lines that are in an 
emergency shutdown system, and which are designed to open 
automatically, from the requirements to be equipped with a cap, blind 
flange, plug, or second valve that seals the open end. We are proposing 
that these open-ended valves and lines follow the requirements of 40 
CFR 63.693(c)(2) for bypass devices that could be used to divert a vent 
stream from the closed-vent system to the atmosphere, which would 
require that each such open-ended line be equipped with either a flow 
indicator or a seal or locking device. We are also proposing 
recordkeeping and reporting requirements in 40 CFR 63.696(j)(2) and 40 
CFR 63.697(b)(6) for these open-ended values and lines.
    We solicit comments on our proposed approach to reducing the 
compliance uncertainty associated with ``sealed'' open-ended valves and 
lines and our proposed requirements for open-ended valves and lines 
that are in an emergency shutdown system and are designed to open 
automatically.
5. Safety Devices, Pressure Tanks, Bypasses and PRDs
    The OSWRO MACT standards contain requirements for safety devices, 
closure devices on pressure tanks, PRDs and bypasses, established with 
the recognition that emission releases to the atmosphere from these 
devices and from bypasses of control equipment occur only in the event 
of unplanned and unpredictable events. While emissions vented to the 
atmosphere in these events may contain HAP that would otherwise be 
subject to the OSWRO MACT emission standards, the OSWRO MACT rule 
followed the EPA's former practice prior to the Sierra Club decision of 
exempting malfunction events from otherwise applicable

[[Page 37878]]

emissions standards. Consequently, as these events were assumed to 
occur during malfunctions, the OSWRO MACT standards did not restrict 
emissions of HAP from these equipment or events to the atmosphere.
    In the Sierra Club decision, the Court determined that the SSM 
exemption violated the CAA and vacated the regulatory provisions in the 
General Provisions containing the exemption. See section IV.D.1 of this 
preamble for additional discussion. To ensure the OSWRO MACT standards 
are consistent with the Court's action, we are proposing to remove the 
SSM exemption from the rule. In addition, in order for our treatment of 
malfunction-caused releases to the atmosphere to conform with the 
reasoning of the Court's ruling, we are proposing to add a provision 
that releases of HAP listed in Table 1 of 40 CFR part 63, subpart DD 
directly to the atmosphere from PRDs and closure devices on pressure 
tanks in off-site material service are prohibited. We are also 
proposing to prohibit bypasses that divert a process vent or closed 
vent system stream to the atmosphere such that it does not first pass 
through an emission control device, except to perform planned routine 
maintenance of the closed-vent system or emission control device for 
tanks, as discussed in section IV.D.3 of this preamble. We are further 
proposing to require owners or operators to keep records and report any 
bypass and the amount of HAP released to the atmosphere with the next 
periodic report. In addition, to add clarity to these proposed 
provisions, we are proposing to add definitions for ``bypass,'' 
``pressure release,'' ``pressure relief device or valve,'' ``in gas/
vapor service,'' ``in light liquid service'' ``in heavy liquid 
service'' and ``in liquid service'' to 40 CFR part 63, subpart DD. We 
are also proposing to remove the definition of ``safety device'' and 
the provisions related to safety devices from 40 CFR part 63, subpart 
DD, which would overlap with and be redundant of parts of the proposed 
definition of ``pressure relief device or valve'' and the provisions 
related to these devices. To our knowledge, pressure relief devices or 
valves are the only safety devices used in OSWRO processes.
    To address potential releases from PRDs, we are also proposing to 
require facility owners or operators subject to the OSWRO MACT 
standards to employ monitoring of PRDs in off-site material service 
using a device or monitoring system that is capable of: (1) Identifying 
the pressure release; (2) recording the time and duration of each 
pressure release; and (3) notifying operators immediately that a 
pressure release is occurring. We are further proposing to require 
owners or operators to keep records and report any pressure release and 
the amount of HAP released to the atmosphere with the next periodic 
report.
    Pressure releases to the atmosphere from PRDs in off-site material 
service have the potential to emit large quantities of HAP. Where a 
release occurs, it is important to identify and mitigate it as quickly 
as possible. We recognize that releases from PRDs sometimes occur in 
order to protect systems from failures that could endanger worker 
safety and the systems that the PRDs are designed to protect. We have 
provided a balanced approach designed to minimize HAP emissions while 
recognizing that these events may be unavoidable even in a well-
designed and maintained system. For purposes of estimating the costs of 
this requirement, we assumed that operators would install electronic 
indicators on each relief device that vents to the atmosphere to 
identify and record the time and duration of each pressure release. 
However, we are proposing that owners and operators could choose to use 
an existing system, such as a parameter monitoring system, as long as 
it is sufficient to identify a pressure release, notify operators 
immediately that a release is occurring and record the time and 
duration of the release.
    Based on our cost assumptions, the nationwide capital cost of 
installing these monitors for the OSWRO industry is approximately $1.75 
million and the annualized cost of installing and operating these 
monitors is $250,000 per year. As noted above, the owner or operator 
may use parameter monitoring systems already in place. Therefore, our 
costs based on the installation of electronic indicators on each relief 
device that vents to the atmosphere is conservative and likely 
overstates the costs.
6. Performance Test Method Clarifications and Alternative Methods
    The OSWRO NESHAP at 40 CFR 63.694 specifies test methods and 
procedures to be used in determining compliance with the requirements 
of subpart DD. We are proposing several minor changes to these 
provisions to correct errors and to provide consistency, clarification 
and flexibility.
    We are proposing several minor clarifications to align the testing 
requirements with standard testing practices. We are proposing that 
test runs last ``at least 1 hour'', rather than stating that tests last 
``1 hour'' in Sec.  63.694(f)(1) and (i)(1). This is consistent with 
standard testing practice and other provisions of the rule that specify 
a minimum sampling time instead of an absolute sampling time. Requiring 
a minimum sampling time allows owners and operators to conduct longer 
sampling runs when necessary. For example, an owner or operator may 
conduct longer sampling runs to achieve a lower detection limit for a 
specific compound. We are proposing to specify that a minimum of three 
test runs are required in Sec.  63.694(l)(3)(i) and (l)(4)(i), 
consistent with the Part 63 General Provisions and standard testing 
practices. We are proposing to specify in Sec.  63.694(m)(2) that in 
the determination of process vent stream flow rate and total HAP 
concentration, the sample site selected must be at the center of the 
vent for vents smaller than 0.10 meter in diameter. EPA Methods 1 and 
1A do not apply to stack diameters smaller than 0.10 meter in diameter, 
and the regulation as currently written states that it is unnecessary 
to traverse vents less than 0.10 meter in diameter, but is unclear on 
how sampling point selection must be chosen. We are proposing to 
clarify that the sampling point must be at the center of the vent; this 
sample point is the point most likely to provide a representative 
sample of the gas stream.
    To provide consistency with other parts of the OSWRO MACT 
standards, we are proposing to clarify the requirements of Sec.  
63.694(j)(3) for determining the maximum HAP vapor pressure for off-
site material in a tank if the Administrator and the owner or operator 
disagree on a determination of the maximum HAP vapor pressure for an 
off-site material stream using knowledge. We are proposing that results 
from direct measurement of the HAP vapor pressure must be used in these 
instances. This is consistent with Sec.  63.694(b)(3)(iv), which uses 
the same language for VOHAP measurements.
    We also are proposing to correct a citation in Sec.  63.694(k)(3). 
The regulation currently references the wrong section of Method 21 for 
instrument response factors. The appropriate section in EPA Method 21 
is 8.1.1, not 3.1.2(a).
    We are proposing to allow the use of either EPA Method 25A or 
Method 18 in Sec.  63.694(l)(3) and (4). We are clarifying that Method 
25A must be used for determining compliance with the enclosed 
combustion device total organic compound (TOC) limit, while Method 18 
is used for determining compliance with the total HAP concentration 
limit. We are making this change because Method 25A is a flame 
ionization method that measures concentration as carbon equivalents. It

[[Page 37879]]

is preferred over Method 18 for the measurement of TOC. Method 18 is 
used to determine the concentration of individual compounds, making it 
appropriate for measuring individual HAPs that can be summed and 
compared with the total HAP limit, especially when a finite list of 
HAPs is specified (such as in Table 1 of the OSWRO NESHAP). Because TOC 
includes all organic compounds (minus methane and ethane) and Method 18 
requires a set list of individual compounds to be measured. In order to 
use Method 18 for TOC measurements, one would have to know every 
organic compound in the gas stream and analyze each individually, which 
is a difficult and nearly impossible task in most cases. Therefore, we 
are proposing that TOC is to be measured with Method 25A and total HAP 
is to be measured with Method 18. The changes in how the test methods 
are applied and how TOC is most appropriately measured result in 
changes in some of the equations in Sec.  63.694 as well.
    We are proposing additional flexibility in some of the test methods 
that are allowed by the OSWRO NESHAP. We are including the use of EPA 
Method 3A as an alternative to EPA Method 3B in Sec.  
63.694(l)(4)(iii)(A) for determining the oxygen concentration to use in 
oxygen correction equations. EPA Method 3A is just as effective as EPA 
Method 3B in determining oxygen concentration. We have also included 
the use of EPA Methods 2F and 2G as options for flow rate measurement 
in Sec.  63.694(l)(2) and (m)(3). These methods are newer velocity 
measurement methods that were published after the original OSWRO rule. 
By allowing these test method alternatives in the rule, we are 
providing greater flexibility to sources and easing the burden on 
sources and delegated agencies by reducing the number of potential 
alternative method requests.
7. Other Clarifications and Corrections
    We are proposing several miscellaneous minor changes to improve the 
clarity of the rule requirements. These proposed changes include:
     Updating the list in Sec.  63.684(b)(5) of combustion 
devices that may be used to destroy the HAP contained in an off-site 
material stream, to include incinerators, boilers or industrial 
furnaces for which the owner or operator complies with the requirements 
of 40 CFR part 63, subpart EEE. Where the OSWRO MACT standards 
currently require that combustion devices used for the purposes of 
compliance with the OSWRO MACT standards must be regulated under 
various subparts of RCRA, many of these units now comply with 40 CFR 
part 63, subpart EEE, which had not been promulgated when the OSWRO 
MACT standards were developed. We are also proposing conforming changes 
to the boiler and process heater control device requirements in Sec.  
63.693(g)(1)(v). These changes clarify that combustion units complying 
with the requirements of subpart EEE may be used for the purposes of 
compliance with the OSWRO MACT standards.
     Revising the tank control level tables and the text in 
Sec.  63.685(b) to clarify the control level required for tanks of any 
capacity (effectively those less than 75 m\3\) with a vapor pressure of 
76.6 kPa or greater. Tanks meeting these capacity and vapor pressure 
thresholds are not included in the control level tables referred to in 
Sec.  63.685(b), currently Tables 3 and 4 of the OSWRO NESHAP, and 
instead text is included in Sec.  63.685(b)(4) for these tanks. To 
clarify the requirements for these tanks, we are proposing to specify 
the requirements for these tanks in the tank control level tables 
(proposed Tables 3, 4 and 5) and remove the text in Sec.  63.685(b)(4).
     Clarifying that where Sec.  63.691 requires the owner or 
operator to control the HAP emitted from equipment leaks in accordance 
with either 40 CFR part 61, subpart V or 40 CFR part 63, subpart H, the 
definitions in 40 CFR 61.241 and 40 CFR 63.161 apply, with the 
differences listed, for the purposes of the OSWRO NESHAP.
     Clarifying the requirement of Sec.  63.683(c)(1)(ii) that 
the average VOHAP concentration of the off-site material must be less 
than 500 ppmw at the point-of-delivery and clarifying the requirements 
of Sec.  63.693(f)(1)(i)(B) and Sec.  63.693(f)(1)(ii)(B) are to 
achieve a total incinerator outlet concentration of less than or equal 
to 20 ppmv on a dry basis corrected to 3 percent oxygen. Due to 
clerical errors, the ppm values of these requirements are not in the 
current OSWRO NESHAP, and we are proposing to insert them.
     Clarifying in Sec. Sec.  63.684(h), 63.693(b)(8) and 
63.694(b)(3)(iv) that the Administrator may require a performance test, 
revisions to a control device design analysis, or that direct 
measurement be used in the determination of a VOHAP concentration, 
rather than that the Administrator may only request such actions.
     Revising several references to the Part 63 General 
Provisions in Table 2 to correct errors, including errors where the 
entries in Table 2 conflict with the regulatory text in subpart DD and 
where references to specific sections of the General Provisions do not 
exist or are reserved.
8. Flare Performance
    In addition to our proposed actions discussed above, we are seeking 
comments on the performance of flares used to control HAP emissions in 
this source category, as governed by the EPA's General Provisions at 40 
CFR 63.11(b). In April 2012, the EPA conducted an external peer review 
of a draft technical report, ``Parameters for Properly Designed and 
Operated Flares'' (http://www.epa.gov/ttn/atw/flare/2012flaretechreport.pdf) (``draft flare technical report''). In this 
report, the EPA evaluated test data and identified a variety of 
parameters that may affect flare performance and that could be 
monitored to help ensure good combustion efficiency. Based on feedback 
received from the external ad-hoc peer review panel, the EPA has since 
undertaken an initiative to re-evaluate parameters that may affect 
overall flare performance at source categories known to use flares for 
controlling HAP emissions (e.g., petroleum refining).
    Currently, OSWRO sources may choose from a variety of control 
techniques to control emissions from this source category. One option 
is to operate a flare to reduce HAP emissions in accordance with the 
provision in 40 CFR 63.693(h). However, responses to the CAA section 
114 questionnaire indicate that flares are not commonly used as control 
devices for this source category, and we know of only one facility that 
uses a flare as a primary control device in order to comply with the 
OSWRO NESHAP. In addition, none of the flare performance data used in 
the draft flare technical report comes from OSWRO sources nor does it 
provide any test data on non-assisted flare types, which based on 
available information, is the only flare type found in the OSWRO source 
category. As indicated in the EPA flare draft technical report, one of 
the primary factors that affects flare performance is over-assisting 
flares with too much steam or air and while this can potentially occur 
in steam-assisted and air-assisted flare designs, non-assisted flare 
types do not have a potential to over-assist. Thus, we have no 
information to suggest that flares at OSWRO sources are achieving poor 
destruction efficiency. We solicit comments on our discussion and 
conclusions regarding flare performance, including additional 
information on flare performance related to this source category.

[[Page 37880]]

Examples of types of information we seek from commenters regarding 
flares for the OSWRO source category include: Frequency of flaring; 
number and types of flares used; waste gas characteristics such as flow 
rate, composition and heat content; assist gas characteristics such as 
target assist gas to waste gas ratios and minimum assist gas flow 
rates; use of flare gas recovery and other flare minimization 
practices; and existing flare monitoring systems.

E. What compliance dates are we proposing?

    Under CAA section 112(d), the proposed compliance date for new and 
existing affected sources for the revised SSM requirements, electronic 
reporting requirements, the revised routine maintenance provisions, the 
operating and pressure release management requirements for PRDs, and 
the revised requirements regarding bypasses and closure devices on 
pressure tanks is the effective date of the final amendments. We are 
proposing this compliance date because available information indicates 
these new and revised requirements should be immediately implementable 
by the facilities.
    We are also proposing that for existing affected sources subject to 
the OSWRO MACT standards, the compliance date for the PRD monitoring 
requirements is 3 years from the effective date of the final 
amendments. This time is needed regardless of whether an owner or 
operator of a facility chooses to comply with the PRD monitoring 
provisions by installing PRD release indicator systems and alarms, 
employing parameter monitoring, routing releases to a control device, 
or choosing another compliance option as permitted under the proposed 
provisions. This time period will allow OSWRO facility owners and 
operators to research equipment and vendors, and to purchase, install, 
test and properly operate any necessary equipment by the compliance 
date. For new affected sources, the proposed compliance date for PRD 
monitoring requirements is the effective date of the final amendments.
    Finally, we are proposing revised requirements for equipment leaks 
and tanks under CAA sections 112(d)(6) and (f)(2). The compliance 
deadlines for standards developed under CAA section 112(f)(2) are 
addressed in CAA sections 112(f)(3) and (4). As provided in CAA Section 
112(f)(4), risk standards shall not apply to existing affected sources 
until 90 days after the effective date of the rule, but the 
Administrator may grant a waiver for a particular source for a period 
of up to 2 years after the effective date. Here, the EPA is already 
aware of the steps needed for OSWRO facilities to comply with the 
proposed standards for equipment leaks and tanks and to reasonably 
estimate the amount of time it will take these facilities to do so. 
Therefore, consistent with CAA section 112(f)(4)(B), we are proposing 
that a two-year compliance period is necessary for the revised tank 
requirements to allow affected facilities to research equipment and 
vendors, purchase, install, test and properly operate any necessary 
equipment by the compliance date. We are also proposing, consistent 
with CAA section 112(f)(4)(B), that a one-year compliance period is 
necessary for the revised equipment leak requirements to allow affected 
facilities that are currently complying with 40 CFR part 61, subpart V 
adequate time to purchase, install and test any necessary equipment and 
modify their existing LDAR programs. In addition, pursuant to CAA 
section 112(d)(6), we are proposing these same compliance dates for the 
revised tank and equipment leak standards. For new affected sources, 
the proposed compliance date for the revised tank and equipment leak 
standards is the effective date of the final amendments.

V. Summary of Cost, Environmental and Economic Impacts

A. What are the affected sources?

    We estimate that there are approximately 52 major source OSWRO 
facilities. Based on available permit information, seven facilities are 
known to be exempt from most of the rule requirements due to the low 
HAP content of the off-site waste they receive or because they comply 
instead with 40 CFR part 61, subpart FF, as allowed by the OSWRO 
NESHAP, and they are not expected to be affected by the proposed rule 
revisions. These facilities are only required to document that the 
total annual quantity of the HAP contained in the off-site material 
received at the plant site is less than 1 megagram per year, and they 
are not subject to any other emissions limits or monitoring, reporting 
or recordkeeping requirements. We are not aware of any new OSWRO 
facilities that are expected to be constructed in the foreseeable 
future.

B. What are the air quality impacts?

    For equipment leaks, we are proposing to eliminate the option of 
complying with 40 CFR part 61, subpart V, and requiring facilities in 
the OSWRO source category to comply with 40 CFR part 63, subpart H, 
including connector monitoring. We estimate the HAP emission reduction 
for this change to be approximately 138 tpy. For tanks, we are 
proposing to require tanks of certain sizes and containing materials 
above certain vapor pressures to use Level 2 controls. We estimate the 
HAP emission reduction for this change to be approximately 73 tpy. We 
do not anticipate any HAP emission reduction from our proposed 
clarification of the rule provision ``seal the open end'' (in the 
context of open-ended valves and lines), clarification of the scope of 
the routine maintenance provisions, or requirement to electronically 
report the results of emissions testing.
    For the proposed revisions to the MACT standards regarding SSM, 
including monitoring of PRDs in off-site material service, we were not 
able to quantify the possible emission reductions so none are included 
in our assessment of air quality impacts.
    Therefore, the estimated total HAP emission reductions for the 
proposed rule revisions for the OSWRO source category are estimated to 
be 211 tpy.

C. What are the cost impacts?

    For equipment leaks, we are proposing to eliminate the option of 
complying with 40 CFR part 61, subpart V, and to require facilities in 
the OSWRO source category to comply with 40 CFR part 63, subpart H 
(including connector monitoring). We estimate the nationwide capital 
costs to be $1.9 million and the annualized costs to be $530,000. For 
tanks, we are proposing to require tanks of certain sizes and 
containing materials above certain vapor pressures to use Level 2 
controls. We estimate the nationwide capital costs to be $76,000 and 
the annualized costs to be $21,000. We do not anticipate any 
quantifiable capital or annualized costs for our proposed definition of 
``seal'' (in the context of open-ended valves and lines), clarification 
of the scope of the routine maintenance provisions and requirement to 
electronically report the results of emissions testing.
    For the proposed requirements to install and operate monitors on 
PRDs, we estimate the nationwide capital costs to be $1.75 million and 
the annualized costs to be $250,000.
    Therefore, the total capital costs for the proposed standards for 
the OSWRO source category are approximately $3.7 million and the total 
annualized costs are approximately $800,000.

D. What are the economic impacts?

    Both the magnitude of control costs needed to comply with a 
regulation and the distribution of these costs among affected 
facilities can have a role in determining how the market will change in 
response to that regulation. Total annualized costs for the proposed

[[Page 37881]]

amendments are estimated to be about $800,000. The average annualized 
cost per facility is estimated to be about $24,000.
    Without detailed industry data, it is not possible to conduct a 
complete quantitative analysis of economic impacts. However, prior 
analyses suggest the impacts of these proposed amendments will be 
minimal. The Economic Impact Analysis for the Final OSWRO NESHAP \26\ 
found that demand for off-site waste services was highly inelastic. 
This means that suppliers are predominantly able to pass along cost 
increases to consumers through higher prices with little, if any, 
decrease in the quantity of service demanded. While we do not have 
specific information on prices charged or the quantity of service 
provided, company revenues are a function of both these factors. The 
cost-to-sales ratio is less than one quarter of one percent for all of 
the 27 firms included in this analysis, suggesting any increase in 
price would be minimal.
---------------------------------------------------------------------------

    \26\ EPA. June 1996.
---------------------------------------------------------------------------

E. What are the benefits?

    We have estimated that this action will achieve HAP emissions 
reduction of 211 tons per year. The proposed standards will result in 
significant reductions in the actual and MACT-allowable emissions of 
HAP and will reduce the actual and potential cancer risks and non-
cancer health effects due to emissions of HAP from this source 
category, as discussed in section IV.B.2. We have not quantified the 
monetary benefits associated with these reductions; however, these 
avoided emissions will result in improvements in air quality and 
reduced negative health effects associate with exposure to air 
pollution of these emissions.

VI. Request for Comments

    We are soliciting comments on all aspects of this proposed action. 
In addition to general comments on this proposed action, we are also 
interested in any additional data that may help to improve the risk 
assessments and other analyses. We are specifically interested in 
receiving any improvements to the data used in the site-specific 
emissions profiles used for risk modeling. Such data should include 
supporting documentation in sufficient detail to allow characterization 
of the quality and representativeness of the data or information. 
Section VII of this preamble provides more information on submitting 
data.

VII. Submitting Data Corrections

    The site-specific emissions profiles used in the source category 
risk and demographic analyses and instructions are available for 
download on the RTR Web page at http://www.epa.gov/ttn/atw/rrisk/rtrpg.html. The data files include detailed information for each HAP 
emissions release point for the facilities included in the source 
category.
    If you believe that the data are not representative or are 
inaccurate, please identify the data in question, provide your reason 
for concern and provide any ``improved'' data that you have, if 
available. When you submit data, we request that you provide 
documentation of the basis for the revised values to support your 
suggested changes. To submit comments on the data downloaded from the 
RTR page, complete the following steps:
    1. Within this downloaded file, enter suggested revisions to the 
data fields appropriate for that information.
    2. Fill in the commenter information fields for each suggested 
revision (i.e., commenter name, commenter organization, commenter email 
address, commenter phone number and revision comments).
    3. Gather documentation for any suggested emissions revisions 
(e.g., performance test reports, material balance calculations).
    4. Send the entire downloaded file with suggested revisions in 
Microsoft[supreg] Access format and all accompanying documentation to 
Docket ID No. EPA-HQ-OAR-2012-0360 (through one of the methods 
described in the ADDRESSES section of this preamble).
    5. If you are providing comments on a single facility or multiple 
facilities, you need only submit one file for all facilities. The file 
should contain all suggested changes for all sources at that facility. 
We request that all data revision comments be submitted in the form of 
updated Microsoft[supreg] Excel files that are generated by the 
Microsoft[supreg] Access file. These files are provided on the RTR Web 
page at: http://www.epa.gov/ttn/atw/rrisk/rtrpg.html.

VIII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is not a ``significant regulatory action'' under the 
terms of Executive Order 12866 (58 FR 51735, October 4, 1993) and is 
therefore not subject to review under Executive Orders 12866 and 13563 
(76 FR 3821, January 21, 2011).

B. Paperwork Reduction Act

    The information collection requirements in this proposed rule have 
been submitted for approval to OMB under the Paperwork Reduction Act, 
44 U.S.C. 3501, et seq. The Information Collection Request (ICR) 
document prepared by the EPA has been assigned the EPA ICR number 
1717.10.
    The information requirements are based on notification, 
recordkeeping and reporting requirements in the NESHAP General 
Provisions (40 CFR part 63, subpart A), which are mandatory for all 
operators subject to national emissions standards. These recordkeeping 
and reporting requirements are specifically authorized by CAA section 
114 (42 U.S.C. 7414). All information submitted to the EPA pursuant to 
the recordkeeping and reporting requirements for which a claim of 
confidentiality is made is safeguarded according to agency policies set 
forth in 40 CFR part 2, subpart B.
    We estimate approximately 52 regulated entities are currently 
subject to subpart DD; however, five facilities are only subject to 
off-site waste HAP content determination requirements and are not 
subject to the emissions standards and other requirements of the OSWRO 
NESHAP due to the low HAP content of the off-site waste they receive. 
Also, two facilities are not subject to the emissions standards and 
other requirements of the OSWRO NESHAP because they comply instead with 
40 CFR part 61, subpart FF, as allowed by the OSWRO NESHAP. Therefore, 
we estimate that there is an annual average of 45 respondents that are 
subject to the annual monitoring, reporting and recordkeeping 
requirements of the regulation. This is a decrease of 191 regulated 
entities from our estimate for the previous ICR (EPA ICR Number 
1717.09, OMB Control Number 2060-0313) for the OSWRO source category. 
The annual monitoring, reporting and recordkeeping burden for this 
collection (averaged over the first 3 years after the effective date of 
the standards) for the proposed amended subpart DD, including existing 
rule provisions unchanged by this proposal, is estimated to be 45,147 
labor hours at a cost of $2.5 million per year. This represents a 
decrease of approximately $15 million and 133,000 labor hours from the 
previous ICR, due primarily to the reduction in the estimated number of 
regulated entities. In order to more accurately assess the change in 
burden resulting from these proposed

[[Page 37882]]

amendments, we estimate that the burden for each of the 45 facilities 
subject to the annual monitoring, reporting and recordkeeping 
requirements of the regulations has increased by $6,000 and 92 labor 
hours from the previous ICR estimate.
    The total burden for the federal government (averaged over the 
first 3 years after the effective date of the standard) is estimated to 
be 449 labor hours per year at an annual cost of $20,200. Burden is 
defined at 5 CFR 1320.3(b).
    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 the 
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, the EPA has established a public docket 
for this rule, which includes this ICR, under Docket ID No. EPA-HQ-OAR-
2012-0360. Submit any comments related to the ICR to the EPA and OMB. 
See the ADDRESSES section at the beginning of this document for where 
to submit comments to the 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 
the EPA. Since OMB is required to make a decision concerning the ICR 
between 30 and 60 days after July 2, 2014, a comment to OMB is best 
assured of having its full effect if OMB receives it by August 1, 2014.
    The final rule will respond to any OMB or public comments on the 
information collection requirements contained in this proposal.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of this proposed rule on 
small entities, small entity is defined as: (1) A small business as 
defined by the Small Business Administration's (SBA) regulations at 13 
CFR 121.201; (2) a small governmental jurisdiction that is a government 
of a city, county, town, school district or special district with a 
population of less than 50,000; and (3) a small organization that is 
any not-for-profit enterprise that is independently owned and operated 
and is not dominant in its field. Facilities in this source category 
are not categorized as a single industry and, as a result, cannot be 
classified under a single NAICS code category. During the development 
of these proposed amendments, the EPA identified 45 facilities affected 
by this proposal. These 45 facilities represent 27 firms in 20 
industries. These industries and the SBA size standards are shown in 
Table 8.

          Table 8--Industries Included in OSWRO Source Category
------------------------------------------------------------------------
        NAICS                  Description           SBA Size standard
------------------------------------------------------------------------
211111...............  Crude Petroleum and         500 employees.
                        Natural Gas Extraction.
221310...............  Water Supply and            $7.0 million annual
                        Irrigation Systems.         receipts.
237310...............  Highway, Street, and        $33.5 million annual
                        Bridge Construction.        receipts.
324110...............  Petroleum Refineries......  1,500 employees.
325180...............  Other Basic Inorganic       1,000 employees.
                        Chemical Manufacturing.
325194...............  Cyclic Crude,               750 employees.
                        Intermediate, and Gum and
                        Wood Chemical
                        Manufacturing.
325199...............  All Other Basic Organic     1,000 employees.
                        Chemical Manufacturing.
325211...............  Plastics Material and       750 employees.
                        Resin Manufacturing.
327310...............  Cement Manufacturing......  750 employees.
331313...............  Alumina Refining and        1,000 employees.
                        Primary Aluminum
                        Production.
333316...............  Photographic and            1,000 employees.
                        Photocopying Equipment
                        Manufacturing.
336411...............  Aircraft Manufacturing....  1,500 employees.
424690...............  Other Chemical and Allied   100 employees.
                        Products Merchant
                        Wholesalers.
561110...............  Office Administrative       $7.0 million annual
                        Services.                   receipts.
562111...............  Solid Waste Collection....  $35.5 million annual
                                                    receipts.
562211...............  Hazardous Waste Treatment   $35.5 million annual
                        and Disposal.               receipts.
562213...............  Solid Waste Combustion and  $35.5 million annual
                        Incinerators.               receipts.
562219...............  Other Nonhazardous Waste    $35.5 million annual
                        Treatment and Disposal.     receipts.
562920...............  Materials Recovery          $19.0 million annual
                        Facilities.                 receipts.
928110...............  National Security \a\.....  n/a.
------------------------------------------------------------------------
\a\ One facility is operated by the U.S. Department of Defense. Small
  business size standards are not established for this sector.

    After considering the economic impacts of this proposed rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. For the 
small business screening analysis, the EPA identified the ultimate 
parent company (firm) for each facility and obtained firm-level 
employment and revenues using various sources, including the American 
Business Directory, Hoovers, corporate Web sites and publically 
available financial reports. The screening analysis shows that four of 
the 27 firms that own facilities in the OSWRO source category can be 
classified as small firms using the SBA size standards for their 
respective industries. Based on the sales test screening methodology, 
all four firms will experience minimal impact, or a cost-to-sales ratio 
of 1 percent or less. Details of this analysis can be found in the memo 
``Economic Impact Analysis for Risk and Technology Review: Off-site 
Waste and Recovery Operations Source Category'' in the docket.
    We continue to be interested in the potential impacts of the 
proposed rule on small entities and welcome comments on issues related 
to such impacts.

D. Unfunded Mandates Reform Act

    This rule does not contain a federal mandate that may result in 
expenditures of $100 million or more for state, local and tribal 
governments, in aggregate, or

[[Page 37883]]

the private sector in any one year. The total annualized cost of this 
rule is estimated to be no more than $800,000 in any one year. Thus, 
this proposed rule is not subject to the requirements of sections 202 
or 205 of the UMRA.
    This proposed rule is also not subject to the requirements of 
section 203 of UMRA because it contains no regulatory requirements that 
might significantly or uniquely affect small governments because it 
contains no requirements that apply to such governments nor does it 
impose obligations upon them.

E. Executive Order 13132: Federalism

    This action 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 Executive Order 13132. None of the facilities subject to 
this action are owned or operated by state governments. Thus, Executive 
Order 13132 does not apply to this proposed rule.
    In the spirit of Executive Order 13132, and consistent with the EPA 
policy to promote communications between the EPA and State and local 
governments, the EPA specifically solicits comment on this proposed 
rule from state and local officials.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have tribal implications, as specified in 
Executive Order 13175 (65 FR 67249, November 9, 2000). There are no 
Off-Site Waste Recovery Operation facilities that are owned or operated 
by tribal governments. Thus, Executive Order 13175 does not apply to 
this action. The EPA specifically solicits comment on this proposed 
action from tribal officials.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    This action is not subject to Executive Order 13045 (62 FR 19885, 
April 23, 1997) because it is not economically significant as defined 
in Executive Order 12866, and because the agency does not believe the 
environmental health risks or safety risks addressed by this action 
present a disproportionate risk to children. Because the proposed rule 
amendments would result in reduced emissions of HAP and reduced risk to 
anyone exposed, the EPA believes that the proposed rule amendments 
would provide additional protection to children. The EPA's risk 
assessments are included in the docket for this proposed rule.
    The public is invited to submit comments or identify peer-reviewed 
studies and data that assess effects of early life exposure to HAP 
emitted by OSWRO facilities.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not subject to Executive Order 13211 (66 FR 28355, 
May 22, 2001), because it is not a significant regulatory action under 
Executive Order 12866.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113 (15 U.S.C. 272 note), directs 
the EPA to use voluntary consensus standards (VCS) in its regulatory 
activities unless to do so would be inconsistent with applicable law or 
otherwise impractical. VCS are technical standards (e.g., materials 
specifications, test methods, sampling procedures and business 
practices) that are developed or adopted by VCS bodies. NTTAA directs 
the EPA to provide Congress, through OMB, explanations when the agency 
decides not to use available and applicable VCS.
    This proposed rule involves technical standards. The EPA proposes 
to add EPA Methods 2F and 2G to the list of methods allowed to 
determine process vent stream gas volumetric flow rate. No applicable 
VCS were identified for these methods. In addition, the EPA is 
proposing to allow EPA Method 3A as an alternative to EPA Method 3B for 
determining the oxygen concentration to use in oxygen correction 
equations. While several candidate VCS were identified (ANSI/ASME PTC 
19-10-1981 Part 10, ASME B133.9-1994 (2001), ISO 10396:1993 (2007), ISO 
12039:2001, ASTM D5835-95 (2013), ASTM D6522-00 (2011), and CAN/CSA 
Z223.2-M86 (1999)), we do not propose to use any of these standards in 
this proposed rule. The use of these VCS would not be practical due to 
lack of equivalency, documentation, validation data and other important 
technical and policy considerations. The EPA also proposes to require 
the use of EPA Method 25A to determine compliance with the control 
device percent reduction requirement, if the owner or operator chooses 
to measure total organic content. While the agency identified two 
candidate VCS (ISO 14965:2000(E), EN 12619 (1999)) as being potentially 
applicable, we do not propose to use either standard in this proposed 
rule. The use of these VCS would not be practical due to the limited 
measurement ranges of these methods. (For more detail, see ``Voluntary 
Consensus Standard Results for NESHAP: Off-Site Waste and Recovery 
Operations 40 CFR Part 63, Subpart DD'' in the docket for this proposed 
rule.)
    The EPA welcomes comments on this aspect of the proposed rule and, 
specifically, invites the public to identify potentially-applicable VCS 
and to explain why such standards should be used in this regulation.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, February 16, 1994) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practical and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    The EPA has determined that this proposed rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority, low income or indigenous populations because it 
increases the level of environmental protection for all affected 
populations without having any disproportionately high and adverse 
human health or environmental effects on any population, including any 
minority, low income or indigenous populations.
    To gain a better understanding of the source category and near 
source populations, the EPA conducted a proximity analysis for OSWRO 
facilities to identify any overrepresentation of minority, low income 
or indigenous populations. This analysis only gives some indication of 
the prevalence of sub-populations that may be exposed to air pollution 
from the sources; it does not identify the demographic characteristics 
of the most highly affected individuals or communities, nor does it 
quantify the level of risk faced by those individuals or communities. 
More information on the source category's risk can be found in section 
IV of this preamble.

[[Page 37884]]

    In determining the aggregate demographic makeup of the communities 
near affected sources, the EPA focused on those census blocks within 3 
miles of affected sources, determined the demographic composition 
(e.g., race, income, etc.) of these census blocks, and compared them to 
the corresponding compositions nationally. The results of this 
proximity analysis show that most demographic categories were below or 
within 20 percent of their corresponding national averages except for 
the African American and minority populations. The African American 
segment of the population within 3 miles of any source affected by this 
proposed rule exceeds the national average by 166 percent, or 21 
percentage points (34 percent versus 13 percent). The minority 
population within 3 miles exceeds the national average by 64 percent, 
or 24 percentage points, (61 percent versus 37 percent). However, as 
noted previously, risks from this source category were found to be 
acceptable for all populations. Additionally, the proposed changes to 
the standard increase the level of environmental protection for all 
affected populations by reducing emissions from equipment leaks and 
tanks.
    Further details concerning this analysis are presented in the 
December 3, 2013 memorandum titled, Environmental Justice Review: Off-
Site Waste and Recovery Operations, RTR, a copy of which is available 
in the docket for this action (EPA-HQ-OAR-2012-0360).

List of Subjects in 40 CFR Part 63

    Environmental protection, Administrative practice and procedures, 
Air pollution control, Hazardous substances, Reporting and 
recordkeeping requirements, Volatile organic compounds.

    Dated: May 30, 2014.
Gina McCarthy,
Administrator.
    For the reasons stated in the preamble, the Environmental 
Protection Agency (EPA) proposes to amend Title 40, chapter I, of the 
Code of Federal Regulations (CFR) as follows:

PART 63--[AMENDED]

0
1. The authority citation for part 63 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart DD--[Amended]

0
2. Section 63.680 is amended by:
0
a. Revising paragraphs (e)(1) and (2); and
0
b. Adding paragraph (g) to read as follows:


Sec.  63.680  Applicability and designation of affected sources.

* * * * *
    (e) * * *
    (1) Existing sources. The owner or operator of an affected source 
that commenced construction or reconstruction before October 13, 1994, 
must achieve compliance with the provisions of this subpart on or 
before the date specified in paragraph (e)(1)(i),(ii), or (iii) of this 
section as applicable to the affected source.
    (i) For an affected source that commenced construction or 
reconstruction before October 13, 1994 and receives off-site material 
for the first time before February 1, 2000, the owner or operator of 
this affected source must achieve compliance with the provisions of the 
subpart (except Sec. Sec.  63.685(b)(1)(ii), 63.691(b), and 
63.691(c)(3)(i) and (ii) of this subpart) on or before February 1, 2000 
unless an extension has been granted by the Administrator as provided 
in 40 CFR 63.6(i). These existing affected sources shall be in 
compliance with the tank requirements of Sec.  63.685(b)(1)(ii) of this 
subpart two years after the publication date of the final amendments on 
[DATE OF PUBLICATION OF THE FINAL RULE IN THE FEDERAL REGISTER], the 
equipment leak requirements of Sec.  63.691(b) of this subpart one year 
after the publication date of the final amendments on [DATE OF 
PUBLICATION OF THE FINAL RULE IN THE FEDERAL REGISTER], and the 
pressure relief device monitoring requirements of Sec.  63.691(c)(3)(i) 
and (ii) of this subpart three years after the publication date of the 
final amendments on [DATE OF PUBLICATION OF THE FINAL RULE IN THE 
FEDERAL REGISTER].
    (ii) For an affected source that commenced construction or 
reconstruction before October 13, 1994, but receives off-site material 
for the first time on or after February 1, 2000, but before [DATE OF 
PUBLICATION OF THE FINAL RULE IN THE FEDERAL REGISTER], the owner or 
operator of the affected source must achieve compliance with the 
provisions of this subpart (except Sec. Sec.  63.685(b)(1)(ii), 
63.691(b), and 63.691(c)(3)(i) and (ii) of this subpart) upon the first 
date that the affected source begins to manage off-site material. These 
existing affected sources shall be in compliance with the tank 
requirements of Sec.  63.685(b)(1)(ii) of this subpart two years after 
the publication date of the final amendments on [DATE OF PUBLICATION OF 
THE FINAL RULE IN THE FEDERAL REGISTER], the equipment leak 
requirements of Sec.  63.691(b) of this subpart one year after the 
publication date of the final amendments on [DATE OF PUBLICATION OF THE 
FINAL RULE IN THE FEDERAL REGISTER], and the pressure relief device 
monitoring requirements of Sec.  63.691(c)(3)(i) and (ii) of this 
subpart three years after the publication date of the final amendments 
on [DATE OF PUBLICATION OF THE FINAL RULE IN THE FEDERAL REGISTER].
    (iii) For an affected source that commenced construction or 
reconstruction before October 13, 1994, but receives off-site material 
for the first time on or after [DATE OF PUBLICATION OF THE FINAL RULE 
IN THE FEDERAL REGISTER], the owner or operator of the affected source 
must achieve compliance with the provisions of this subpart (except 
Sec. Sec.  63.685 (b)(1)(ii), 63.691(b), and 63.691(c)(3)(i) and (ii) 
of this subpart) upon the first date that the affected source begins to 
manage off-site material. These existing affected sources shall be in 
compliance with the tank requirements of Sec.  63.685(b)(1)(ii) of this 
subpart two years after the publication date of the final amendments on 
[DATE OF PUBLICATION OF THE FINAL RULE IN THE FEDERAL REGISTER], the 
equipment leak requirements of Sec.  63.691(b) of this subpart one year 
after the publication date of the final amendments on [DATE OF 
PUBLICATION OF THE FINAL RULE IN THE FEDERAL REGISTER], and the 
pressure relief device monitoring requirements of Sec.  63.691(c)(3)(i) 
and (ii) of this subpart three years after the publication date of the 
final amendments on [DATE OF PUBLICATION OF THE FINAL RULE IN THE 
FEDERAL REGISTER].
    (2) New sources. The owner or operator of an affected source for 
which construction or reconstruction commences on or after October 13, 
1994, must achieve compliance with the provisions of this subpart 
(except Sec. Sec.  63.685(b)(2), 63.691(b), and 63.691(c)(i) and (ii) 
of this subpart) on or before July 1, 1996, or upon initial startup of 
operations, whichever date is later as provided in 40 CFR 63.6(b). New 
affected sources that commenced construction or reconstruction after 
October 13, 1994, but on or before [INSERT DATE OF PUBLICATION IN THE 
FEDERAL REGISTER], shall be in compliance with the tank requirements of 
Sec.  63.685(b)(2) of this subpart two years after the publication date 
of the final amendments, the equipment leak requirements of Sec.  
63.691(b) of this

[[Page 37885]]

subpart one after the publication date of the final amendments, and the 
pressure relief device monitoring requirements of Sec.  63.691(c)(i) 
and (ii) of this subpart three years after the effective date of the 
final amendments. New affected sources that commence construction or 
reconstruction after July 2, 2014 shall be in compliance with the tank 
requirements of Sec.  63.685(b)(2) of this subpart, the equipment leak 
requirements of Sec.  63.691(b) of this subpart, and the pressure 
relief device monitoring requirements of Sec.  63.691(c)(3)(i) and (ii) 
of this subpart upon initial startup or by the effective date of the 
final amendments, whichever is later.
* * * * *
    (g) Applicability of this subpart. (1) The emission limitations set 
forth in this subpart and the emission limitations referred to in this 
subpart shall apply at all times except during periods of non-operation 
of the affected source (or specific portion thereof) resulting in 
cessation of the emissions to which this subpart applies.
    (2) The owner or operator shall not shut down items of equipment 
that are required or utilized for compliance with this subpart during 
times when emissions are being routed to such items of equipment, if 
the shutdown would contravene requirements of this subpart applicable 
to such items of equipment.
0
3. Section 63.681 is amended by:
0
a. Adding, in alphabetical order, definitions for ``Bypass'', ``In gas/
vapor service'', ``In heavy liquid service'', ``In light liquid 
service'', ``In liquid service'', ``Pressure release'', and ``Pressure 
relief device or valve'';
0
b. Revising the definitions of ``Point-of-treatment'' and ``Process 
vent''; and
0
c. Removing the definition of ``Safety device'' to read as follows:


Sec.  63.681  Definitions.

* * * * *
    Bypass means diverting a process vent or closed vent system stream 
to the atmosphere such that it does not first pass through an emission 
control device.
* * * * *
    In gas/vapor service means that a piece of equipment in off-site 
material service contains a gas or vapor at operating conditions.
    In heavy liquid service means that a piece of equipment in off-site 
material service is not in gas/vapor service or in light liquid 
service.
    In light liquid service means that a piece of equipment in off-site 
material service contains a liquid that meets the following conditions:
    (1) The vapor pressure of one or more of the organic compounds is 
greater than 0.3 kilopascals at 20 [deg]C,
    (2) The total concentration of the pure organic compounds 
constituents having a vapor pressure greater than 0.3 kilopascals at 20 
[deg]C is equal to or greater than 20 percent by weight of the total 
process stream, and
    (3) The fluid is a liquid at operating conditions.
    Note to In light liquid service. Vapor pressures may be determined 
by the methods described in 40 CFR 60.485(e)(1).
    In liquid service means that a piece of equipment in off-site 
material service is not in gas/vapor service.
* * * * *
    Point-of-treatment means a point after the treated material exits 
the treatment process but before the first point downstream of the 
treatment process exit where the organic constituents in the treated 
material have the potential to volatilize and be released to the 
atmosphere. For the purpose of applying this definition to this 
subpart, the first point downstream of the treatment process exit is 
not a fugitive emission point due to an equipment leak from any of the 
following equipment components: Pumps, compressors, valves, connectors, 
instrumentation systems, or pressure relief devices.
    Pressure release means the emission of materials resulting from the 
system pressure being greater than the set pressure of the pressure 
relief device. This release can be one release or a series of releases 
over a short time period.
    Pressure relief device or valve means a safety device used to 
prevent operating pressures from exceeding the maximum allowable 
working pressure of the process equipment. A common pressure relief 
device is a spring-loaded pressure relief valve. Devices that are 
actuated either by a pressure of less than or equal to 2.5 pounds per 
square inch gauge or by a vacuum are not pressure relief devices.
* * * * *
    Process vent means an open-ended pipe, stack, or duct through which 
a gas stream containing HAP is continuously or intermittently 
discharged to the atmosphere from any of the processes listed in Sec.  
63.680(c)(2)(i) through (vi) of this subpart. For the purpose of this 
subpart, a process vent is none of the following: a pressure relief 
device; an open-ended line or other vent that is subject to the 
equipment leak control requirements under Sec.  63.691 of this subpart; 
or a stack or other vent that is used to exhaust combustion products 
from a boiler, furnace, process heater, incinerator, or other 
combustion device.
* * * * *
0
4. Section 63.683 is revised by adding paragraphs (e) and (f) to read 
as follows:


Sec.  63.683  Standards: General.

* * * * *
    (e) General Duty. At all times, the owner or operator must operate 
and maintain any affected source, including associated air pollution 
control equipment and monitoring equipment, in a manner consistent with 
safety and good air pollution control practices for minimizing 
emissions. The general duty to minimize emissions does not require the 
owner operator to make any further efforts to reduce emissions if 
levels required by the applicable standard have been achieved. 
Determination of whether a source is operating in compliance with 
operation and maintenance requirements will be based on information 
available to the Administrator, which may include, but is not limited 
to, monitoring results, review of operation and maintenance procedures, 
review of operation and maintenance records, and inspection of the 
source.
    (f) In addition to the cases listed in Sec.  63.695(e)(4) of this 
subpart, deviation means any of the cases listed in paragraphs (f)(1) 
through (6) of this section.
    (1) Any instance in which an affected source subject to this 
subpart, or an owner or operator of such a source, fails to meet any 
requirement or obligation established by this subpart, including, but 
not limited to, any emission limit, operating limit or work practice 
standard.
    (2) When a performance test indicates that emissions of a pollutant 
in Table 1 to this subpart are exceeding the emission standard for the 
pollutant specified in Table 1 to this subpart.
    (3) When the average value of a monitored operating parameter, 
based on the data averaging period for compliance specified in Sec.  
63.695 of this subpart, does not meet the operating limit specified in 
Sec.  63.693 of this subpart.
    (4) When an affected source discharges directly into the atmosphere 
from any of the sources specified in paragraphs (f)(4)(i) and (ii) of 
this section.
    (i) A pressure relief device, as defined in Sec.  63.681 of this 
subpart.
    (ii) A bypass, as defined in Sec.  63.681 of this subpart.
    (5) Any instance in which the affected source subject to this 
subpart, or an owner or operator of such a source, fails to meet any 
term or condition specified

[[Page 37886]]

in paragraph (f)(5)(i) or (ii) of this section.
    (i) Any term or condition that is adopted to implement an 
applicable requirement in this subpart.
    (ii) Any term or condition relating to compliance with this subpart 
that is included in the operating permit for an affected source to 
obtain such a permit.
    (6) Any failure to collect required data, except for periods of 
monitoring system malfunctions, repairs associated with monitoring 
system malfunctions, and required monitoring system quality assurance 
or quality control activities (including, as applicable, calibration 
checks and required zero and span adjustments).
0
5. Section 63.684 is amended by adding paragraph (b)(5)(v) and revising 
paragraph (h) to read as follows:


Sec.  63.684  Standards: Off-site Material Treatment.

* * * * *
    (b) * * *
    (5) * * *
    (v) An incinerator, boiler, or industrial furnace for which the 
owner or operator has submitted a Notification of Compliance under 40 
CFR 63.1207(j) and 63.1210(d) and complies with the requirements of 40 
CFR part 63, subpart EEE at all times (including times when non-
hazardous waste is being burned).
* * * * *
    (h) The Administrator may at any time conduct or require that the 
owner or operator conduct testing necessary to demonstrate that a 
treatment process is achieving the applicable performance requirements 
of this section. The testing shall be conducted in accordance with the 
applicable requirements of this section. The Administrator may elect to 
have an authorized representative observe testing conducted by the 
owner or operator.
0
6. Section 63.685 is amended by:
0
a. Revising paragraphs (b) introductory text, (b)(1), and (b)(2);
0
b. Removing paragraph (b)(4);
0
c. Revising paragraphs (c)(1), (c)(2)(i), (c)(2)(iii)(B), (g)(2), and 
(h)(3); and
0
d. Removing paragraph (i)(3) and redesignating paragraph (i)(4) as 
paragraph (i)(3) to read as follows:


Sec.  63.685  Standards: Tanks.

* * * * *
    (b) According to the date an affected source commenced construction 
or reconstruction and the date an affected source receives off-site 
material for the first time as established in Sec.  63.680(e)(i) 
through (iii) of this subpart, the owner or operator shall control air 
emissions from each tank subject to this section in accordance with 
either paragraph (b)(1)(i) or (ii) of this section.
    (1)(i) For a tank that is part of an existing affected source but 
the tank is not used for a waste stabilization process as defined in 
Sec.  63.681 of this subpart, the owner or operator shall determine 
whether the tank is required to use either Tank Level 1 controls or 
Tank Level 2 controls as specified for the tank by Table 3 of this 
subpart based on the off-site material maximum HAP vapor pressure, the 
tank's design capacity. The owner or operator shall control air 
emissions from a tank required by Table 3 to use Tank Level 1 controls 
in accordance with the requirements of paragraph (c) of this section. 
The owner or operator shall control air emissions from a tank required 
by Table 3 to use Tank Level 2 controls in accordance with the 
requirements of paragraph (d) of this section.
    (ii) For a tank that is part of an existing affected source but the 
tank is not used for a waste stabilization process as defined in Sec.  
63.681 of this subpart, the owner or operator shall determine whether 
the tank is required to use either Tank Level 1 controls or Tank Level 
2 controls as specified for the tank by Table 4 of this subpart based 
on the off-site material maximum HAP vapor pressure and the tank's 
design capacity. The owner or operator shall control air emissions from 
a tank required by Table 4 to use Tank Level 1 controls in accordance 
with the requirements of paragraph (c) of this section. The owner or 
operator shall control air emissions from a tank required by Table 4 to 
use Tank Level 2 controls in accordance with the requirements of 
paragraph (d) of this section.
    (2) For a tank that is part of a new affected source but the tank 
is not used for a waste stabilization process as defined in Sec.  
63.681 of this subpart, the owner or operator shall determine whether 
the tank is required to use either Tank Level 1 controls or Tank Level 
2 controls as specified for the tank by Table 5 of this subpart based 
on the off-site material maximum HAP vapor pressure and the tank's 
design capacity. The owner or operator shall control air emissions from 
a tank required by Table 5 to use Tank Level 1 controls in accordance 
with the requirements of paragraph (c) of this section. The owner or 
operator shall control air emissions from a tank required by Table 5 to 
use Tank Level 2 controls in accordance with the requirements of 
paragraph (d) of this section.
* * * * *
    (c) * * *
    (1) The owner or operator shall determine the maximum HAP vapor 
pressure for an off-site material to be managed in the tank using Tank 
Level 1 controls before the first time the off-site material is placed 
in the tank. The maximum HAP vapor pressure shall be determined using 
the procedures specified in Sec.  63.694(j) of this subpart. 
Thereafter, the owner or operator shall perform a new determination 
whenever changes to the off-site material managed in the tank could 
potentially cause the maximum HAP vapor pressure to increase to a level 
that is equal to or greater than the maximum HAP vapor pressure limit 
for the tank design capacity category specified in Table 3, Table 4, or 
Table 5 of this subpart, as applicable to the tank.
    (2) * * *
    (i) The owner or operator controls air emissions from the tank in 
accordance with the provisions specified in subpart OO of 40 CFR part 
63--National Emission Standards for Tanks--Level 1, except that 40 CFR 
63.902(c)(2) and (3) shall not apply for the purposes of this subpart.
* * * * *
    (iii) * * *
    (B) At all other times, air emissions from the tank must be 
controlled in accordance with the provisions specified in 40 CFR part 
67, subpart OO--National Emission Standards for Tanks--Level 1, except 
that 40 CFR 63.902(c)(2) and (3) shall not apply for the purposes of 
this subpart.
* * * * *
    (g) * * *
    (2) Whenever an off-site material is in the tank, the fixed roof 
shall be installed with each closure device secured in the closed 
position and the vapor headspace underneath the fixed roof vented to 
the control device except that to the control device except that 
venting to the control device is not required, and opening of closure 
devices or removal of the fixed roof is allowed at the following times:
    (i) To provide access to the tank for performing routine 
inspection, maintenance, or other activities needed for normal 
operations. Examples of such activities include those times when a 
worker needs to open a port to sample liquid in the tank, or when a 
worker needs to open a hatch to maintain or repair equipment. Following 
completion of the activity, the owner or operator shall promptly secure 
the closure device in the closed position or reinstall the cover, as 
applicable, to the tank.
    (ii) To remove accumulated sludge or other residues from the bottom 
of the tank.
* * * * *

[[Page 37887]]

    (h) * * *
    (3) Whenever an off-site material is in the tank, the tank shall be 
operated as a closed system that does not vent to the atmosphere except 
at those times when purging of inerts from the tank is required and the 
purge stream is routed to a closed-vent system and control device 
designed and operated in accordance with the requirements of Sec.  
63.693 of this subpart.
    (i) * * *
    (3) The owner or operator shall inspect and monitor the closed-vent 
system and control device as specified in Sec.  63.693.
0
7. Section 63.686 is amended by revising paragraphs (b)(1) through (3) 
to read as follows:


Sec.  63.686  Standards: Oil-water and organic water separators.

* * * * *
    (b) * * *
    (1) A floating roof in accordance with all applicable provisions 
specified in 40 CFR part 63, subpart VV--National Emission Standards 
for Oil-Water Separators and Organic-Water Separators, except that 
Sec. Sec.  63.1043(c)(2), 63.1044(c)(2), and 63.1045(b)(3)(i) shall not 
apply for the purposes of this subpart. For portions of the separator 
where it is infeasible to install and operate a floating roof, such as 
over a weir mechanism, the owner or operator shall comply with the 
requirements specified in paragraph (b)(2) of this section.
    (2) A fixed-roof that is vented through a closed-vent system to a 
control device in accordance with all applicable provisions specified 
in 40 CFR part 63, subpart VV--National Emission Standards for Oil-
Water Separators and Organic-Water Separators, except that Sec. Sec.  
63.1043(c)(2), 63.1044(c)(2), and 63.1045(b)(3)(i) shall not apply for 
the purposes of this subpart.
    (3) A pressurized separator that operates as a closed system in 
accordance with all applicable provisions specified in 40 CFR part 63, 
subpart VV--National Emission Standards for Oil-Water Separators and 
Organic-Water Separators, except that Sec. Sec.  63.1043(c)(2), 
63.1044(c)(2), and 63.1045(b)(3)(i) shall not apply for the purposes of 
this subpart.
0
8. Section 63.687 is amended by revising paragraphs (b)(1) and (2) to 
read as follows:


Sec.  63.687  Standards: Surface impoundments.

* * * * *
    (b) * * *
    (1) A floating membrane cover in accordance with the applicable 
provisions specified in 40 CFR part 63, subpart QQ--National Emission 
Standards for Surface Impoundments, except that Sec. Sec.  63.942(c)(2) 
and (3) and 63.943(c)(2) shall not apply for the purposes of this 
subpart; or
    (2) A cover that is vented through a closed-vent system to a 
control device in accordance with all applicable provisions specified 
in 40 CFR part 63, subpart QQ--National Emission Standards for Surface 
Impoundments, except that Sec. Sec.  63.942(c)(2) and (3) and 
63.943(c)(2) shall not apply for the purposes of this subpart.
0
9. Section 63.688 is amended by revising paragraphs (b)(1)(i), 
(b)(1)(ii), and (b)(3)(i) to read as follows:


Sec.  63.688  Standards: Containers.

* * * * *
    (b) * * *
    (1) * * *
    (i) The owner or operator controls air emissions from the container 
in accordance with the standards for Container Level 1 controls as 
specified in 40 CFR part 63, subpart PP--National Emission Standards 
for Containers, except that Sec. Sec.  63.922(d)(4) and (5) and 
63.923(d)(4) and (5) shall not apply for the purposes of this subpart.
    (ii) As an alternative to meeting the requirements in paragraph 
(b)(1)(i) of this section, an owner or operator may choose to control 
air emissions from the container in accordance with the standards for 
either Container Level 2 controls or Container Level 3 controls as 
specified in subpart PP of 40 CFR part 63--National Emission Standards 
for Containers, except that Sec. Sec.  63.922(d)(4) and (5) and 
63.923(d)(4) and (5) shall not apply for the purposes of this subpart.
* * * * *
    (3) * * *
    (i) The owner or operator controls air emissions from the container 
in accordance with the standards for Container Level 2 controls as 
specified in 40 CFR part 63, subpart PP--National Emission Standards 
for Containers, except that Sec. Sec.  63.922(d)(4) and (5) and 
63.923(d)(4) and (5) shall not apply for the purposes of this subpart.
* * * * *
0
10. Section 63.689 is amended by revising paragraph (d)(5) to read as 
follows:


Sec.  63.689  Standards: Transfer systems.

* * * * *
    (d) * * *
    (5) Whenever an off-site material is in the transfer system, the 
cover shall be installed with each closure device secured in the closed 
position, except the opening of closure devices or removal of the cover 
is allowed to provide access to the transfer system for performing 
routine inspection, maintenance, repair, or other activities needed for 
normal operations. Examples of such activities include those times when 
a worker needs to open a hatch or remove the cover to repair conveyance 
equipment mounted under the cover or to clear a blockage of material 
inside the system. Following completion of the activity, the owner or 
operator shall promptly secure the closure device in the closed 
position or reinstall the cover, as applicable.
* * * * *
0
11. Section 63.691 is amended by:
0
a. Revising paragraph (b); and
0
b. Adding paragraph (c) to read as follows:


Sec.  63.691  Standards: Equipment leaks.

* * * * *
    (b) According to the date an affected source commenced construction 
or reconstruction and the date an affected source receives off-site 
material for the first time, as established in Sec.  63.680(e)(i) 
through (iii) of this subpart, the owner or operator shall control the 
HAP emitted from equipment leaks in accordance with the applicable 
provisions specified in either paragraph (b)(1) or (2) of this section.
    (1)(i) The owner or operator controls the HAP emitted from 
equipment leaks in accordance with Sec. Sec.  61.241 through 61.247 in 
40 CFR part 61, subpart V--National Emission Standards for Equipment 
Leaks, with the difference noted in paragraphs (b)(1)(iii) and (iv) of 
this section for the purposes of this subpart; or
    (ii) The owner or operator controls the HAP emitted from equipment 
leaks in accordance with Sec. Sec.  63.161 through 63.182 in 40 CFR 
part 63, subpart H--National Emission Standards for Organic Hazardous 
Air Pollutants from Equipment Leaks, with the differences noted in 
paragraphs (b)(2)(i) through (iv) of this section for the purposes of 
this subpart.
    (iii) On or after [DATE OF PUBLICATION OF THE FINAL RULE AMENDMENTS 
IN THE FEDERAL REGISTER], for the purpose of complying with the 
requirements of 40 CFR 61.242-6(a)(2), the open end is sealed when 
instrument monitoring of the open-ended valve or line conducted 
according to Method 21 of 40 CFR part 60, appendix A indicates no 
readings of 500 ppm or greater.
    (iv) On or after [DATE OF PUBLICATION OF THE FINAL RULE IN THE 
FEDERAL REGISTER], for the purpose of complying with the requirements 
of 40 CFR 61.242-6(d),

[[Page 37888]]

open-ended valves or lines in an emergency shutdown system which are 
designed to open automatically in the event of a process upset and that 
are exempt from the requirements in 40 CFR 61.242-6(a), (b), and (c) 
must comply with the requirements in Sec.  63.693(c)(2) of this 
subpart.
    (2) The owner or operator controls the HAP emitted from equipment 
leaks in accordance with Sec. Sec.  63.161 through Sec.  63.183 in 40 
CFR part 63, subpart H--National Emission Standards for Organic 
Hazardous Air Pollutants for Equipment Leaks, with the differences 
noted in paragraphs (b)(2)(i) through (v) of this section for the 
purposes of this subpart.
    (i) For each valve in gas/vapor or in light liquid service, as 
defined in Sec.  63.681 of this subpart, that is part of an affected 
source under this subpart, an instrument reading that defines a leak is 
500 ppm or greater as detected by Method 21 of 40 CFR part 60, appendix 
A.
    (ii) For each pump in light liquid service, as defined in Sec.  
63.681 of this subpart, that is part of an affected source under this 
subpart, an instrument reading that defines a leak is 1,000 ppm or 
greater as detected by Method 21 of 40 CFR part 60, appendix A. Repair 
is not required unless an instrument reading of 2,000 ppm or greater is 
detected.
    (iii) On or after [DATE OF PUBLICATION OF THE FINAL RULE IN THE 
FEDERAL REGISTER], for the purpose of complying with the requirements 
of 40 CFR 63.167(a)(2), the open end is sealed when instrument 
monitoring of the open-ended valve or line conducted according to 
Method 21 of 40 CFR part 60, appendix A indicates no readings of 500 
ppm or greater.
    (iv) On or after [DATE OF PUBLICATION OF THE FINAL RULE IN THE 
FEDERAL REGISTER], for the purpose of complying with the requirements 
of 40 CFR 63.167(d), open-ended valves or lines in an emergency 
shutdown system which are designed to open automatically in the event 
of a process upset and that are exempt from the requirements in 40 CFR 
63.167(a), (b), and (c) must comply with the requirements in Sec.  
63.693(c)(2) of this subpart.
    (v) For the purposes of this subpart, the pressure relief device 
requirements of Sec.  63.691(c) of this subpart rather than those of 40 
CFR 63.165 shall apply.
    (c) Requirements for pressure relief devices. Except as provided in 
paragraph (c)(4) of this section, the owner or operator must comply 
with the requirements specified in paragraphs (c)(1) through (3) of 
this section for pressure relief devices in off-site material service.
    (1) Operating requirements. Except during a pressure release event, 
operate each pressure relief device in off-site material gas or vapor 
service with an instrument reading of less than 500 ppm above 
background as detected by Method 21 of 40 CFR part 60, appendix A.
    (2) Pressure release requirements. For pressure relief devices in 
off-site material gas or vapor service, the owner or operator must 
comply with either paragraph (c)(2)(i) or (ii) of this section 
following a pressure release, as applicable.
    (i) If the pressure relief device does not consist of or include a 
rupture disk, the pressure relief device shall be returned to a 
condition indicated by an instrument reading of less than 500 ppm above 
background, as detected by Method 21 of 40 CFR part 60, appendix A, no 
later than 5 calendar days after the pressure release device returns to 
off-site material service following a pressure release, except as 
provided in 40 CFR 63.171.
    (ii) If the pressure relief device consists of or includes a 
rupture disk, except as provided in 40 CFR 63.171, install a 
replacement disk as soon as practicable but no later than 5 calendar 
days after the pressure release.
    (3) Pressure release management. Except as provided in paragraph 
(c)(4) of this section, emissions of HAP listed in Table 1 of this 
subpart may not be discharged directly to the atmosphere from pressure 
relief devices in off-site material service, and according to the date 
an affected source commenced construction or reconstruction and the 
date an affected source receives off-site material for the first time, 
as established in Sec.  63.680(e)(1)(i) through (iii) of this subpart, 
the owner or operator must comply with the requirements specified in 
paragraphs (c)(3)(i) and (ii) of this section for all pressure relief 
devices in off-site material service.
    (i) The owner or operator must equip each pressure relief device in 
off-site material service with a device(s) or use a monitoring system. 
The device or monitoring system may be either specific to the pressure 
release device itself or may be associated with the process system or 
piping, sufficient to indicate a pressure release to the atmosphere. 
Examples of these types of devices or monitoring systems include, but 
are not limited to, a rupture disk indicator, magnetic sensor, motion 
detector on the pressure relief valve stem. The devices or monitoring 
systems must be capable of meeting the requirements specified in 
paragraphs (c)(3)(i)(A) through (C) of this section.
    (A) Identifying the pressure release;
    (B) Recording the time and duration of each pressure release; and
    (C) Notifying operators immediately that a pressure release is 
occurring.
    (ii) If any pressure relief device in off-site material service 
releases directly to the atmosphere as a result of a pressure release 
event, the owner or operator must calculate the quantity of HAP listed 
in Table 1 of this subpart released during each pressure release event 
and report this quantity as required in Sec.  63.697(b)(5). 
Calculations may be based on data from the pressure relief device 
monitoring alone or in combination with process parameter monitoring 
data and process knowledge.
    (4) Pressure relief devices routed to a drain system, process or 
control device. If a pressure relief device in off-site material 
service is designed and operated to route all pressure releases through 
a closed vent system to a drain system, process or control device, 
paragraphs (c)(1), (2), and (3) of this section do not apply. The 
closed vent system and the process or control device (if applicable) 
must meet the requirements of Sec.  63.693 of this subpart. The drain 
system (if applicable) must meet the requirements of Sec.  63.689 of 
this subpart.
0
12. Section 63.693 is amended by:
0
a. Revising paragraphs (b)(3) and (8), (c)(1)(ii), and (c)(2) 
introductory text;
0
b. Adding paragraph (c)(2)(iii); and
0
c. Revising paragraphs (f)(1)(i)(B) and (ii)(B) and (g)(1)(v) to read 
as follows:


Sec.  63.693  Standards: Closed-vent systems and control devices.

* * * * *
    (b) * * *
    (3) Whenever gases or vapors containing HAP are routed from a tank 
through a closed-vent system connected to a control device used to 
comply with the requirements of Sec.  63.685(b)(1), (2), or (3) of this 
subpart, the control device must be operating except as provided for in 
paragraphs (b)(3)(i) and (ii) of this section.
    (i) The control device may only be bypassed for the purpose of 
performing planned routine maintenance of the closed-vent system or 
control device in situations when the routine maintenance cannot be 
performed during periods that tank emissions are vented to the control 
device.
    (ii) On an annual basis, the total time that the closed-vent system 
or control device is bypassed to perform routine maintenance shall not 
exceed 240 hours per each calendar year.
* * * * *

[[Page 37889]]

    (8) In the case when an owner or operator chooses to use a design 
analysis to demonstrate compliance of a control device with the 
applicable performance requirements specified in this section as 
provided for in paragraphs (d) through (g) of this section, the 
Administrator may require that the design analysis be revised or 
amended by the owner or operator to correct any deficiencies identified 
by the Administrator. If the owner or operator and the Administrator do 
not agree on the acceptability of using the design analysis (including 
any changes required by the Administrator) to demonstrate that the 
control device achieves the applicable performance requirements, then 
the disagreement must be resolved using the results of a performance 
test conducted by the owner or operator in accordance with the 
requirements of Sec.  63.694(l) of this subpart. The Administrator may 
choose to have an authorized representative observe the performance 
test conducted by the owner or operator. Should the results of this 
performance test not agree with the determination of control device 
performance based on the design analysis, then the results of the 
performance test will be used to establish compliance with this 
subpart.
* * * * *
    (c) * * *
    (1) * * *
    (ii) A closed-vent system that is designed to operate at a pressure 
below atmospheric pressure. The system shall be equipped with at least 
one pressure gauge or other pressure measurement device that can be 
read from a readily accessible location to verify that negative 
pressure is being maintained in the closed-vent system when the control 
device is operating.
    (2) In situations when the closed-vent system includes bypass 
devices that could be used to divert a vent stream from the closed-vent 
system to the atmosphere at a point upstream of the control device 
inlet, each bypass device must be equipped with either a flow indicator 
as specified in paragraph (c)(2)(i) of this section or a seal or 
locking device as specified in paragraph (c)(2)(ii) of this section, 
except as provided for in paragraph (c)(2)(iii) of this section:
* * * * *
    (iii) Equipment needed for safety reasons, including low leg 
drains, open-ended valves and lines not in emergency shutdown systems, 
and pressure relief devices subject to the requirements of Sec.  
63.691(c) of this subpart are not subject to the requirements of 
paragraphs (c)(2)(i) and (ii) of this section.
* * * * *
    (f) * * *
    (1) * * *
    (i) * * *
    (B) To achieve a total incinerator outlet concentration for the 
TOC, less methane and ethane, of less than or equal to 20 ppmv on a dry 
basis corrected to 3 percent oxygen.
    (ii) * * *
    (B) To achieve a total incinerator outlet concentration for the 
HAP, listed in Table 1 of this subpart, of less than or equal to 20 
ppmv on a dry basis corrected to 3 percent oxygen.
* * * * *
    (g) * * *
    (1) * * *
    (v) Introduce the vent stream to a boiler or process heater for 
which the owner or operator either has been issued a final permit under 
40 CFR part 270 and complies with the requirements of 40 CFR part 266, 
subpart H; or has certified compliance with the interim status 
requirements of 40 CFR part 266, subpart H; or has submitted a 
Notification of Compliance under 40 CFR 63.1207(j) and 63.1210(d) and 
complies with the requirements of 40 CFR part 63, subpart EEE at all 
times (including times when non-hazardous waste is being burned).
* * * * *
0
13. Section 63.694 is amended by revising paragraphs (b)(3)(iv), 
(f)(1), (i)(1), (j)(3), (k)(3), (l) introductory text, (l)(3) 
introductory text, (l)(3)(i), (l)(3)(ii)(B), (l)(4) introductory text, 
(l)(4)(i), (l)(4)(ii)(A) and (B), (l)(4)(iii)(A), and (m)(2) and (3) to 
read as follows:


Sec.  63.694  Testing methods and procedures.

* * * * *
    (b) * * *
    (3) * * *
    (iv) In the event that the Administrator and the owner or operator 
disagree on a determination of the average VOHAP concentration for an 
off-site material stream using knowledge, then the results from a 
determination of VOHAP concentration using direct measurement as 
specified in paragraph (b)(2) of this section shall be used to 
establish compliance with the applicable requirements of this subpart. 
The Administrator may perform or require that the owner or operator 
perform this determination using direct measurement.
    (f) * * *
    (1) The actual HAP mass removal rate (MR) shall be determined based 
on results for a minimum of three consecutive runs. The sampling time 
for each run shall be at least 1 hour.
* * * * *
    (i) * * *
    (1) The actual HAP mass removal rate (MRbio) shall be 
determined based on results for a minimum of three consecutive runs. 
The sampling time for each run shall be at least 1 hour.
* * * * *
    (j) * * *
    (3) Use of knowledge to determine the maximum HAP vapor pressure of 
the off-site material. Documentation shall be prepared and recorded 
that presents the information used as the basis for the owner's or 
operator's knowledge that the maximum HAP vapor pressure of the off-
site material is less than the maximum vapor pressure limit listed in 
Table 3, Table 4, or Table 5 of this subpart for the applicable tank 
design capacity category. Examples of information that may be used 
include: the off-site material is generated by a process for which at 
other locations it previously has been determined by direct measurement 
that the off-site material maximum HAP vapor pressure is less than the 
maximum vapor pressure limit for the appropriate tank design capacity 
category. In the event that the Administrator and the owner or operator 
disagree on a determination of the maximum HAP vapor pressure for an 
off-site material stream using knowledge, then the results from a 
determination of HAP vapor pressure using direct measurement as 
specified in paragraph (j)(2) of this section shall be used to 
establish compliance with the applicable requirements of this subpart. 
The Administrator may perform or require that the owner or operator 
perform this determination using direct measurement.
    (k) * * *
    (3) The detection instrument shall meet the performance criteria of 
Method 21 of 40 CFR part 60, appendix A, except the instrument response 
factor criteria in section 8.1.1 of Method 21 shall be for the weighted 
average composition of the organic constituents in the material placed 
in the unit at the time of monitoring, not for each individual organic 
constituent.
* * * * *
    (l) Control device performance test procedures. Performance tests 
shall be conducted under such conditions as the Administrator specifies 
to the owner or operator based on representative performance of the 
affected source for the period being tested. Representative conditions 
exclude periods of startup and shutdown. The owner or operator may not 
conduct performance tests

[[Page 37890]]

during periods of malfunction. The owner or operator must record the 
process information that is necessary to document operating conditions 
during the test and include in such record an explanation to support 
that such conditions represent normal operation. Upon request, the 
owner or operator shall make available to the Administrator such 
records as may be necessary to determine the conditions of performance 
tests.
* * * * *
    (3) To determine compliance with the control device percent 
reduction requirement, the owner or operator shall use Method 18 of 40 
CFR part 60, appendix A to measure the HAP in Table 1 of this subpart 
or Method 25A of 40 CFR part 60, appendix A to measure TOC. Method 18 
may be used to measure methane and ethane, and the measured 
concentration may be subtracted from the Method 25A measurement. 
Alternatively, any other method or data that has been validated 
according to the applicable procedures in Method 301 in 40 CFR part 63, 
appendix A may be used. The following procedures shall be used to 
calculate percent reduction efficiency:
    (i) A minimum of three sample runs must be performed. The minimum 
sampling time for each run shall be 1 hour. For Method 18, either an 
integrated sample or a minimum of four grab samples shall be taken. If 
grab sampling is used, then the samples shall be taken at approximately 
equal intervals in time such as 15 minute intervals during the run.
    (ii) * * *
    (B) When the TOC mass rate is calculated, the average concentration 
reading (minus methane and ethane) measured by Method 25A of 40 CFR 
part 60, appendix A shall be used in the equation in paragraph 
(l)(3)(ii)(A) of this section.
* * * * *
    (4) To determine compliance with the enclosed combustion device 
total HAP concentration limit of this subpart, the owner or operator 
shall use Method 18 of 40 CFR part 60, appendix A to measure the total 
HAP in Table 1 of this subpart of Method 25A of 40 CFR part 60, 
appendix A to measure TOC. Method 18 may be used to measure methane and 
ethane and the measured concentration may be subtracted from the Method 
25A measurement. Alternatively, any other method or data that has been 
validated according to Method 301 in appendix A of this part, may be 
used. The following procedures shall be used to calculate parts per 
million by volume concentration, corrected to 3 percent oxygen:
    (i) A minimum of three sample runs must be performed. The minimum 
sampling time for each run shall be 1 hour. For Method 18, either an 
integrated sample or a minimum of four grab samples shall be taken. If 
grab sampling is used, then the samples shall be taken at approximately 
equal intervals in time, such as 15 minute intervals during the run.
    (ii) * * *
    (A) The TOC concentration (CTOC) is the average 
concentration readings provided by Method 25 A of 40 CFR part 60, 
appendix A, minus the concentration of methane and ethane.
    (B) The total HAP concentration (CHAP) shall be computed 
according to the following equation:
[GRAPHIC] [TIFF OMITTED] TP02JY14.002

Where:

CHAP = Total concentration of HAP compounds listed in 
Table 1 of this subpart, dry basis, parts per million by volume.
Cij = Concentration of sample components j of sample i, 
dry basis, parts per million by volume.
n = Number of components in the sample.
x = Number of samples in the sample run.

    (iii) * * *
    (A) The emission rate correction factor or excess air, integrated 
sampling and analysis procedures of Method 3B of 40 CFR part 60, 
appendix A shall be used to determine the oxygen concentration 
(%O2dry). Alternatively, the owner or operator may use 
Method 3A of 40 CFR part 60, appendix A to determine the oxygen 
concentration. The samples shall be collected during the same time that 
the samples are collected for determining TOC concentration or total 
HAP concentration.
* * * * *
    (m) * * *
    (2) No traverse site selection method is needed for vents smaller 
than 0.10 meter in diameter. For vents smaller than 0.10 meter in 
diameter, sample at the center of the vent.
    (3) Process vent stream gas volumetric flow rate must be determined 
using Method 2, 2A, 2C, 2D, 2F, or 2G of 40 CFR part 60, appendix A, as 
appropriate.
* * * * *
0
14. Section 63.695 is amended by:
0
a. Revising paragraph (a) introductory text;
0
b. Adding paragraph (a)(5);
0
c. Revising paragraphs (e)(4) and (5); and
0
d. Removing paragraphs (e)(6) and (7) to read as follows:


Sec.  63.695  Inspection and monitoring requirements.

    (a) The owner or operator must install, calibrate, maintain, and 
operate all monitoring system components according to Sec. Sec.  63.8 
of this part, 63.684(e), 63.693(d)(3), (e)(3), (f)(3), (g)(3), and 
(h)(3) of this subpart, and paragraph (a)(5) of this section and 
perform the inspection and monitoring procedures specified in 
paragraphs (a)(1) through (4) of this section.
* * * * *
    (5)(i) Except for periods of monitoring system malfunctions, 
repairs associated with monitoring system malfunctions and required 
monitoring system quality assurance or quality control activities 
(including, as applicable, calibration checks and required zero and 
span adjustments), the owner or operator must operate the continuous 
monitoring system at all times the affected source is operating. A 
monitoring system malfunction is any sudden, infrequent, not reasonably 
preventable failure of the monitoring system to provide data. 
Monitoring system failures that are caused in part by poor maintenance 
or careless operation are not malfunctions. The owner or operator is 
required to complete monitoring system repairs in response to 
monitoring system malfunctions and to return them monitoring system to 
operation as expeditiously as practicable.
    (ii) The owner or operator may not use data recorded during 
monitoring system malfunctions, repairs associated with monitoring 
system malfunctions, or required monitoring system quality assurance or 
control activities in calculations used to report emissions or 
operating levels. The owner or operator must use all the data collected 
during all other required data collection periods in assessing the 
operation of the control device and associated control system. The 
owner or operator must report any periods for which the monitoring 
system failed to collect required data.
* * * * *
    (e) * * *
    (4) A deviation for a given control device is determined to have 
occurred when the monitoring data or lack of monitoring data result in 
any one of the criteria specified in paragraphs (e)(4)(i) through (iii) 
of this section being met. When multiple operating parameters are 
monitored for the same control device and during the same operating day 
more than one of these operating parameters meets a deviation criterion 
specified in paragraphs (e)(4)(i) through (iii) of this

[[Page 37891]]

section, then a single deviation is determined to have occurred for the 
control device for that operating day.
    (i) A deviation occurs when the daily average value of a monitored 
operating parameter is less than the minimum operating parameter limit 
(or, if applicable, greater than the maximum operating parameter limit) 
established for the operating parameter in accordance with the 
requirements of paragraph (e)(3) of this section.
    (ii) A deviation occurs when the period of control device operation 
is 4 hours or greater in an operating day and the monitoring data are 
insufficient to constitute a valid hour of data for at least 75 percent 
of the operating hours. Monitoring data are insufficient to constitute 
a valid hour of data if measured values are unavailable for any of the 
15-minute periods within the hour.
    (iii) A deviation occurs when the period of control device 
operation is less than 4 hours in an operating day and more than 1 of 
the hours during the period does not constitute a valid hour of data 
due to insufficient monitoring data. Monitoring data are insufficient 
to constitute a valid hour of data if measured values are unavailable 
for any of the 15-minute periods within the hour.
    (5) For each deviation, except when the deviation occurs during 
periods of non-operation of the unit or the process that is vented to 
the control device (resulting in cessation of HAP emissions to which 
the monitoring applies), the owner or operator shall be deemed to have 
failed to have applied control in a manner that achieves the required 
operating parameter limits. Failure to achieve the required operating 
parameter limits is a violation of this standard.
* * * * *
0
15. Section 63.696 is amended by revising paragraph (h) and adding 
paragraphs (i) and (j) to read as follows:


Sec.  63.696  Recordkeeping requirements.

* * * * *
    (h) An owner or operator shall record the malfunction information 
specified in paragraphs (h)(1) through (3) of this section.
    (1) In the event that an affected unit fails to meet an applicable 
standard, record the number of failures. For each failure record the 
date, time and duration of the failure.
    (2) For each failure to meet an applicable standard, record and 
retain a list of the affected sources or equipment, an estimate of the 
volume of each regulated pollutant emitted over any emission limit and 
a description of the method used to estimate the emissions.
    (3) Record actions taken to minimize emissions in accordance with 
Sec.  63.683(e) of this subpart and any corrective actions taken to 
return the affected unit to its normal or usual manner of operation.
    (i) For pressure relief devices in off-site material service, keep 
records of the information specified in paragraphs (i)(1) through (5) 
of this section, as applicable.
    (1) A list of identification numbers for pressure relief devices 
that the owner or operator elects to route emissions through a closed-
vent system to a control device, process or drain system under the 
provisions in Sec.  63.691(c)(4) of this subpart.
    (2) A list of identification numbers for pressure relief devices 
that do not consist of or include a rupture disk, subject to the 
provisions in Sec.  63.691(c)(2)(i) of this subpart.
    (3) A list of identification numbers for pressure relief devices 
equipped with rupture disks, subject to the provisions in Sec.  
63.691(c)(2)(ii) of this subpart.
    (4) The dates and results of the Method 21 of 40 CFR part 60, 
appendix A, monitoring following a pressure release for each pressure 
relief device subject to the provisions in Sec.  63.691(c)(2)(i) of 
this subpart. The results of each monitoring event shall include:
    (i) The measured background level.
    (ii) The maximum instrument reading measured at each pressure 
relief device.
    (5) For pressure relief devices in off-site material service 
subject to Sec.  63.691(c)(3) of this subpart, keep records of each 
pressure release to the atmosphere, including the following 
information:
    (i) The source, nature, and cause of the pressure release.
    (ii) The date, time, and duration of the pressure release.
    (iii) An estimate of the quantity of HAP listed in Table 1 of this 
subpart emitted during the pressure release and the calculations used 
for determining this quantity.
    (iv) The actions taken to prevent this pressure release.
    (v) The measures adopted to prevent future such pressure releases.
    (j)(1) For pressure tank closure devices, as specified in Sec.  
63.685(h)(2) of this subpart, keep records of each release to the 
atmosphere, including the information specified in paragraphs (j)(3) 
through (7) of this section.
    (2) For each closed vent system that includes bypass devices that 
could divert a stream away from the control device and into the 
atmosphere, as specified in Sec.  63.693(c)(2) of this subpart, and 
each open-ended valve or line in an emergency shutdown system which is 
designed to open automatically in the event of a process upset, as 
specified in 40 CFR 63.167(d) or 40 CFR 61.242-6(d), keep records of 
each release to the atmosphere, including the information specified in 
paragraphs (j)(3) through (9) of this section.
    (3) The source, nature, and cause of the release.
    (4) The date, time, and duration of the release.
    (5) An estimate of the quantity of HAP listed in Table 1 of this 
subpart emitted during the release and the calculations used for 
determining this quantity.
    (6) The actions taken to prevent this release.
    (7) The measures adopted to prevent future such release.
    (8) Hourly records of whether the bypass flow indicator specified 
under Sec.  63.693(c)(2) of this subpart was operating and whether a 
diversion was detected at any time during the hour, as well as records 
of the times of all periods when the vent stream is diverted from the 
control device or the flow indicator is not operating.
    (9) Where a seal mechanism is used to comply with Sec.  
63.693(c)(2) of this subpart, hourly records of flow are not required. 
In such cases, the owner or operator shall record that the monthly 
visual inspection of the seals or closure mechanism has been done, and 
shall record the duration of all periods when the seal mechanism is 
broken, the bypass line valve position has changed, or the key for a 
lock-and-key type lock has been checked out, and records of any car-
seal that has broken.
0
16. Section 63.697 is amended by:
0
a. Revising paragraph (a) introductory text, adding paragraphs 
(a)(1)(i) and (ii) and (a)(3);
0
b. Revising paragraph (b)(3) and (4); and
0
c. Adding paragraphs (b)(5) and (6) to read as follows:


Sec.  63.697  Reporting requirements.

    (a) Each owner or operator of an affected source subject to this 
subpart must comply with the notification requirements specified in 
paragraph (a)(1) of this section and the reporting requirements 
specified in paragraphs (a)(2) and (3) of this section.
    (1) * * *
    (i) For pressure relief devices in off-site material service 
subject to the requirements of Sec.  63.691(c) of this subpart, the 
owner or operator must submit the information listed in paragraph 
(a)(1)(ii) of this section in the notification of compliance status

[[Page 37892]]

required under Sec.  63.9(h) of this part within 150 days after the 
first applicable compliance date for pressure relief device monitoring.
    (ii) For pressure relief devices in off-site material service, a 
description of the device or monitoring system to be implemented, 
including the pressure relief devices and process parameters to be 
monitored (if applicable), a description of the alarms or other methods 
by which operators will be notified of a pressure release, and a 
description of how the owner or operator will determine the information 
to be recorded under Sec.  63.696(i)(5)(ii) through (iii) of this 
subpart (i.e., the duration of the pressure release and the methodology 
and calculations for determining the quantity of HAP listed in Table 1 
of this subpart emitted during the pressure release).
* * * * *
    (3) Electronic reporting. Within 60 days after the date of 
completing each performance test (as defined in Sec.  63.2 of this 
part) required by this subpart, the owner or operator must submit the 
results of the performance test according to the manner specified by 
either paragraph (a)(3)(i) or (ii) of this section.
    (i) For data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT Web site 
(http://www.epa.gov/ttn/chief/ert/index.html), the owner or operator 
must submit the results of the performance test to the EPA via the 
Compliance and Emissions Data Reporting Interface (CEDRI) accessed 
through the EPA's Central Data Exchange (CDX) (http://cdx.epa.gov/epa_home.asp). Performance test data must be submitted in a file format 
generated through the use of the EPA's ERT. Owners or operators who 
claim that some of the performance test information being submitted is 
confidential business information (CBI) must submit a complete file 
generated through the use of the EPA's ERT, including information 
claimed to be CBI, on a compact disc, flash drive, or other commonly 
used electronic storage media to the EPA. The electronic media must be 
clearly marked as CBI and mailed to U.S. EPA/OAPQS/CORE CBI Office, 
Attention: WebFIRE Administrator, MD C404-02, 4930 Old Page Rd., 
Durham, NC 27703. The same ERT file with the CBI omitted must be 
submitted to the EPA via the EPA's CDX as described earlier in this 
paragraph (a)(3)(i).
    (ii) For data collected using test methods that are not supported 
by the EPA's ERT as listed on the EPA's ERT Web site, the owner or 
operator must submit the results of the performance test to the 
Administrator at the appropriate address listed in 40 CFR 60.4.
    (b) * * *
    (3) Reports of malfunctions. If a source fails to meet an 
applicable standard, report such events in the Periodic Report. Report 
the number of failures to meet an applicable standard. For each 
instance, report the date, time and duration of each failure. For each 
failure the report must include a list of the affected sources or 
equipment, an estimate of the volume of each regulated pollutant 
emitted over any emission limit, and a description of the method used 
to estimate the emissions.
    (4) A summary report specified in Sec.  63.10(e)(3) of this part 
shall be submitted on a semiannual basis (i.e., once every 6-month 
period). The summary report must include a description of all 
deviations as defined in Sec.  63.695(e) of this subpart that have 
occurred during the 6-month reporting period. For each deviation caused 
when the daily average value of a monitored operating parameter is less 
than the minimum operating parameter limit (or, if applicable, greater 
than the maximum operating parameter limit), the report must include 
the daily average values of the monitored parameter, the applicable 
operating parameter limit, and the date and duration of the period that 
the deviation occurred. For each deviation caused by lack of monitoring 
data, the report must include the date and duration of period when the 
monitoring data were not collected and the reason why the data were not 
collected.
    (5) For pressure relief devices in off-site material service 
subject to Sec.  63.691(c) of this subpart, Periodic Reports must 
include the information specified in paragraphs (b)(5)(i) through (iii) 
of this section.
    (i) For pressure relief devices in off-site material service 
subject to Sec.  63.691(c) of this subpart, report the results of all 
monitoring conducted within the reporting period.
    (ii) For pressure relief devices in off-site material service 
subject to Sec.  63.691(c)(2)(i) of this subpart, report any instrument 
reading of 500 ppm above background or greater, if detected more than 5 
days after the pressure release.
    (iii) For pressure relief devices in off-site material service 
subject to Sec.  63.691(c)(3) of this subpart, report each pressure 
release to the atmosphere, including the following information:
    (A) The source, nature, and cause of the pressure release.
    (B) The date, time, and duration of the pressure release.
    (C) An estimate of the quantity of HAP listed in Table 1 of this 
subpart emitted during the pressure release and the method used for 
determining this quantity.
    (D) The actions taken to prevent this pressure release.
    (E) The measures adopted to prevent future such pressure releases.
    (6) Pressure tank closure device or bypass deviation report. The 
owner or operator must submit to the Administrator the information 
specified in paragraph (b)(6)(iv) of this section when any of the 
conditions in paragraphs (b)(6)(i) through (iii) of this section are 
met.
    (i) Any pressure tank closure device, as specified in Sec.  
63.685(h)(2) of this subpart, has released to the atmosphere.
    (ii) Any closed vent system that includes bypass devices that could 
divert a vent a stream away from the control device and into the 
atmosphere, as specified in Sec.  63.693(c)(2) of this subpart, has 
released directly to the atmosphere.
    (iii) Any open-ended valve or line in an emergency shutdown system 
which is designed to open automatically in the event of a process 
upset, as specified in 40 CFR 63.167(d) or 40 CFR 61.242-6(d), has 
released directly to the atmosphere.
    (iv) The pressure tank closure device or bypass deviation report 
must include the information specified in paragraphs (b)(6)(iv)(A) 
through (E) of this section.
    (A) The source, nature and cause of the release.
    (B) The date, time and duration of the discharge.
    (C) An estimate of the quantity of HAP listed in Table 1 of this 
subpart emitted during the release and the method used for determining 
this quantity.
    (D) The actions taken to prevent this release.
    (E) The measures adopted to prevent future such releases.
* * * * *
0
17. Section 63.698 is amended by revising paragraph (c) introductory 
text and adding paragraph (c)(5) to read as follows:


Sec.  63.698  Implementation and enforcement.

* * * * *
    (c) The authorities that cannot be delegated to State, local, or 
Tribal agencies are as specified in paragraphs (c)(1) through (5) of 
this section.
* * * * *
    (5) Approval of alternatives to the electronic reporting 
requirements in Sec.  63.697(a)(3).
0
18. Table 2 to subpart DD of part 63 is amended by:

[[Page 37893]]

0
a. Removing entries 63.1(a)(13) and 63.1(a)(14);
0
b. Revising entries 63.1(b)(2), 63.1(c)(3), and 63.1(c)(4);
0
c. Removing entry 63.4(a)(1) through 63.4(a)(3) and adding entries 
63.4(a)(1)-63.4(a)(2) and 63.4(a)(3);
0
d. Revising entries 63.4(a)(5) and 63.5(a)(1);
0
e. Revising entries 63.5(b)(5), 63.6(b)(3), 63.6(b)(4);
0
f. Removing entry 63.6(e) and adding entries 63.6(e)(1)(i) through 
63.6(e)(1)(iii), 63.6(e)(2), and 63.6(e)(3);
0
g. Revising entry 63.6(f)(1);
0
h. Adding entry 63.7(a)(4);
0
i. Revising entries 63.7(e)(1) and 63.7(f);
0
j. Revising entry 63.8(c)(1)(iii);
0
k. Revising entry 63.9(g);
0
l. Revising entries 63.10(b)(2)(i) through (v);
0
m. Removing entry 63.10(c) and adding entries 63.10(c)(1)-(6), 
63.10(c)(7)-(8), and 63.10(c)(9)-(15);
0
n. Removing entries 63.10(d)(5)(i) and 63.10(d)(5)(ii), and adding 
entry 63.10(d)(5);
0
o. Removing entry 63.10(e) and adding entries 63.10(e)(1)-63.10(e)(2), 
63.10(e)(3), and 63.10(e)(4); and
0
p. Adding entry 63.16 to read as follows:

 Table 2 to Subpart DD of Part 63--Applicability of Paragraphs in Subpart A of This Part 63--General Provisions
                                                  to Subpart DD
----------------------------------------------------------------------------------------------------------------
              Subpart A reference                   Applies to Subpart DD                 Explanation
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
63.1(b)(2)....................................  No...........................  Reserved.
 
                                                  * * * * * * *
63.1(c)(3)....................................  No...........................  Reserved.
63.1(c)(4)....................................  No...........................  Reserved.
 
                                                  * * * * * * *
63.4(a)(1)-63.4(a)(2).........................  Yes..........................
63.4(a)(3)....................................  No...........................  Reserved.
 
                                                  * * * * * * *
63.4(a)(5)....................................  No...........................  Reserved.
 
                                                  * * * * * * *
63.5(a)(1)....................................  Yes..........................
 
                                                  * * * * * * *
63.5(b)(5)....................................  No...........................  Reserved.
 
                                                  * * * * * * *
63.6(b)(3)....................................  No...........................
63.6(b)(4)....................................  No...........................
 
                                                  * * * * * * *
63.6(e)(1)(i).................................  No...........................  See Sec.   63.683(e) of this
                                                                                subpart for general duty
                                                                                requirement.
63.6(e)(1)(ii)................................  No...........................  .................................
63.6(e)(1)(iii)...............................  Yes..........................  .................................
63.6(e)(2)....................................  No...........................  Reserved.
63.6(e)(3)....................................  No...........................
63.6(f)(1)....................................  No...........................
 
                                                  * * * * * * *
63.7(a)(4)....................................  Yes..........................
 
                                                  * * * * * * *
63.7(e)(1)....................................  No...........................  See Sec.   63.694(l) of this
                                                                                subpart.
 
                                                  * * * * * * *
63.7(f).......................................  Yes..........................
 
                                                  * * * * * * *
63.8(c)(1)(iii)...............................  No...........................
 
                                                  * * * * * * *
63.9(g).......................................  Yes..........................
 
                                                  * * * * * * *
63.10(b)(2)(i)................................  No...........................
63.10(b)(2)(ii)...............................  No...........................  See Sec.   63.696(h) of this
                                                                                subpart for recordkeeping of (1)
                                                                                date, time and duration; (2)
                                                                                listing of affected source or
                                                                                equipment, and an estimate of
                                                                                the volume of each regulated
                                                                                pollutant emitted over the
                                                                                standard; and (3) actions to
                                                                                minimize emissions and correct
                                                                                the failure.
63.10(b)(2)(iii)..............................  Yes..........................
63.10(b)(2)(iv)...............................  No...........................
63.10(b)(2)(v)................................  No...........................
 

[[Page 37894]]

 
                                                  * * * * * * *
63.10(c)(1)-(6)...............................  No...........................
63.10(c)(7)-(8)...............................  Yes..........................
63.10(9)-(15).................................  No...........................
 
                                                  * * * * * * *
63.10(d)(5)...................................  No...........................  See Sec.   63.697(b)(3) of this
                                                                                subpart for reporting of
                                                                                malfunctions.
63.10(e)(1)-63.10(e)(2).......................  No...........................
63.10(e)(3)...................................  Yes..........................
63.10(e)(4)...................................  No...........................
 
                                                  * * * * * * *
63.16.........................................  No...........................
----------------------------------------------------------------------------------------------------------------

* * * * *
0
19. Table 3 to subpart DD of part 63 is revised to read as follows:

   Table 3 to Subpart DD of Part 63--Tank Control Levels for Tanks at
     Existing Affected Sources as Required by 40 CFR 63.685(b)(1)(i)
------------------------------------------------------------------------
                                Maximum HAP vapor
                                 pressure of off-
  Tank design capacity (cubic     site material      Tank control level
            meters)              managed in tank
                                  (kilopascals)
------------------------------------------------------------------------
Design capacity less than 75    Maximum HAP vapor  Level 1.
 m\3\.                           pressure less
                                 than 76.6 kPa.
Design capacity less than 75    Maximum HAP vapor  Level 2, except that
 m\3\.                           pressure equal     fixed roof tanks
                                 to or greater      equipped with an
                                 than 76.6 kPa.     internal floating
                                                    roof and tanks
                                                    equipped with an
                                                    external floating
                                                    roof as provided for
                                                    in Sec.
                                                    63.685(d)(1) and (2)
                                                    of this subpart
                                                    shall not be used.
Design capacity equal to or     Maximum HAP vapor  Level 1.
 greater than 75 m\3\ and less   pressure less
 than 151 m\3\.                  than 27.6 kPa.
                                Maximum HAP vapor  Level 2.
                                 pressure equal
                                 to or greater
                                 than 27.6 kPa.
Design capacity equal to or     Maximum HAP vapor  Level 1.
 greater than 151 m\3\.          pressure less
                                 than 5.2 kPa.
                                Maximum HAP vapor  Level 2.
                                 pressure equal
                                 to or greater
                                 than 5.2 kPa.
------------------------------------------------------------------------

0
20. Table 4 to subpart DD of part 63 is revised to read as follows:

   Table 4 to Subpart DD of Part 63--Tank Control Levels for Tanks at
    Existing Affected Sources as Required by 40 CFR 63.685(b)(1)(ii)
------------------------------------------------------------------------
                                Maximum HAP vapor
                                 pressure of off-
  Tank design capacity (cubic     site material      Tank control level
            meters)              managed in tank
                                  (kilopascals)
------------------------------------------------------------------------
Design capacity less than 75    Maximum HAP vapor  Level 1.
 m\3\.                           pressure less
                                 than 76.6 kPa.
Design capacity less than 75    Maximum HAP vapor  Level 2, except that
 m\3\.                           pressure equal     fixed roof tanks
                                 to or greater      equipped with an
                                 than 76.6 kPa.     internal floating
                                                    roof and tanks
                                                    equipped with an
                                                    external floating
                                                    roof as provided for
                                                    in Sec.
                                                    63.685(d)(1) and (2)
                                                    of this subpart
                                                    shall not be used.
Design capacity equal to or     Maximum HAP vapor  Level 1.
 greater than 75 m\3\ and less   pressure less
 than 151 m\3\.                  than 13.1 kPa.
                                Maximum HAP vapor  Level 2.
                                 pressure equal
                                 to or greater
                                 than 13.1 kPa.
Design capacity equal to or     Maximum HAP vapor  Level 1.
 greater than 151 m\3\.          pressure less
                                 than 5.2 kPa.
                                Maximum HAP vapor  Level 2.
                                 pressure equal
                                 to or greater
                                 than 5.2 kPa.
------------------------------------------------------------------------


[[Page 37895]]

0
21. Table 5 is added to subpart DD of part 63 to read as follows:

 Table 5 to Subpart DD of Part 63--Tank Control Levels for Tanks at New
           Affected Sources as Required by 40 CFR 63.685(b)(2)
------------------------------------------------------------------------
                                Maximum HAP vapor
                                 pressure of off-
  Tank design capacity (cubic     site material      Tank control level
            meters)              managed in tank
                                  (kilopascals)
------------------------------------------------------------------------
Design capacity less than 38    Maximum HAP vapor  Level 1.
 m\3\.                           pressure less
                                 than 76.6 kPa.
Design capacity less than 38    Maximum HAP vapor  Level 2, except that
 m\3\.                           pressure equal     fixed roof tanks
                                 to or greater      equipped with an
                                 than 76.6 kPa.     internal floating
                                                    roof and tanks
                                                    equipped with an
                                                    external floating
                                                    roof as provided for
                                                    in Sec.
                                                    63.685(d)(1) and (2)
                                                    of this subpart
                                                    shall not be used.
Design capacity equal to or     Maximum HAP vapor  Level 1.
 greater than 38 m\3\ and less   pressure less
 than 151 m\3\.                  than 13.1 kPa.
                                Maximum HAP vapor  Level 2.
                                 pressure equal
                                 to or greater
                                 than 13.1 kPa.
Design capacity equal to or     Maximum HAP vapor  Level 1.
 greater than 151 m\3\.          pressure less
                                 than 0.7 kPa.
                                Maximum HAP vapor  Level 2.
                                 pressure equal
                                 to or greater
                                 than 0.7 kPa.
------------------------------------------------------------------------

[FR Doc. 2014-13490 Filed 7-1-14; 8:45 am]
BILLING CODE 6560-50-P