```

[Federal Register Volume 79, Number 6 (Thursday, January 9, 2014)]
[Proposed Rules]
[Pages 1675-1731]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-30132]

[[Page 1675]]

Vol. 79

Thursday,

No. 6

January 9, 2014

Part II

Environmental Protection Agency

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40 CFR Part 63

National Emission Standards for Hazardous Air Pollutants: Generic 
Maximum Achievable Control Technology Standards; and Manufacture of 
Amino/Phenolic Resins; Proposed Rule

Federal Register / Vol. 79 , No. 6 / Thursday, January 9, 2014 / 
Proposed Rules

[[Page 1676]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2012-0133; FRL-9903-68-OAR]
RIN 2060-AR49

National Emission Standards for Hazardous Air Pollutants: Generic 
Maximum Achievable Control Technology Standards; and Manufacture of 
Amino/Phenolic Resins

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing amendments, with regard to regulations 
applicable to three industrial source categories, to two national 
emission standards for hazardous air pollutants (NESHAP): NESHAP for 
Source Categories: Generic Maximum Achievable Control Technology 
Standards; and NESHAP: Manufacture of Amino/Phenolic Resins. The three 
source categories addressed in this action are Acrylic and Modacrylic 
Fibers Production, Polycarbonate Production and Amino/Phenolic Resins 
Production. For all three of these source categories, the EPA is 
proposing decisions concerning the residual risk and technology 
reviews. The EPA is also proposing amendments to correct and clarify 
regulatory provisions related to emissions during periods of startup, 
shutdown and malfunction; add provisions for affirmative defense; add 
requirements for electronic reporting of performance test results; 
clarify provisions pertaining to open-ended valves and lines; add 
monitoring requirements for pressure relief devices; and add standards 
for previously unregulated hazardous air pollutant (HAP) emissions 
sources for certain emission points. We estimate that these proposed 
amendments will reduce HAP emissions from these three source categories 
by a combined 22 tons per year.

DATES: Comments. Comments must be received on or before March 10, 2014. 
A copy of comments on the information collection provisions should be 
submitted to the Office of Management and Budget (OMB) on or before 
February 10, 2014.
    Public Hearing. If anyone contacts the EPA requesting a public 
hearing by January 24, 2014, we will hold a public hearing on February 
10, 2014. If a hearing is requested, the last day to pre-register in 
advance to speak at the hearing will be February 3, 2014. Additionally, 
requests to speak will be taken the day of the hearing at the hearing 
registration desk, although preferences on speaking times may not be 
able to be fulfilled. If you require the service of a translator or 
special accommodations such as audio description, please let us know at 
the time of registration. If no one contacts the EPA requesting a 
public hearing to be held concerning this proposed rule by January 24, 
2014, a public hearing will not take place. For further information on 
the hearing, see section I.E of this preamble.

ADDRESSES: Comments. Submit your comments, identified by Docket ID No. 
EPA-HQ-OAR-2012-0133, by one of the following methods:
    http://www.regulations.gov: Follow the online instructions 
for submitting comments.
     Email: a-and-r-docket@epa.gov, Attention Docket ID No. 
EPA-HQ-OAR-2012-0133.
     Fax: (202) 566-9744, Attention Docket ID No. EPA-HQ-OAR-
2012-0133.
     Mail: U.S. Postal Service, send comments to: EPA Docket 
Center, EPA West (Air Docket), Attention Docket ID No. EPA-HQ-OAR-2012-
0133, U.S. Environmental Protection Agency, Mailcode: 2822T, 1200 
Pennsylvania Ave. 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 Delivery: U.S. Environmental Protection Agency, EPA 
West (Air Docket), Room 3334, 1301 Constitution Ave. NW., Washington, 
DC 20004, Attention Docket ID No. EPA-HQ-OAR-2012-0133. 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-
2012-0133. 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 avoid the use of 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 rulemaking under 
Docket ID No. EPA-HQ-OAR-2012-0133. 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, EPA West, 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 a public hearing is requested by January 24, 
2014, it will be held on February 10, 2014, at the EPA's Research 
Triangle Park Campus, 109 T.W. Alexander Drive, Research Triangle Park, 
North Carolina 27711. The hearing will convene at 10:00 a.m. (Eastern 
Standard Time) and end at 5:00 p.m. (Eastern Standard Time). A lunch 
break will be held from 12:00 p.m. (Eastern Standard Time) until 1:00 
p.m. (Eastern Standard Time). Please contact Ms. Virginia Hunt at (919) 
541-0832 or at hunt.virginia@epa.gov to request a

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hearing, to determine if a hearing will be held and to register to 
speak at the hearing, if one is held.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Mr. Nick Parsons, Sector Policies and Programs Division 
(E143-01), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-5372; fax number: (919) 541-0246; 
and email address: parsons.nick@epa.gov. For specific information 
regarding the risk modeling methodology, contact Mr. Mark Morris, 
Health and Environmental Impacts Division (C539-02), Office of Air 
Quality Planning and Standards, U.S. Environmental Protection Agency, 
Research Triangle Park, North Carolina 27711; telephone number: (919) 
541-5416; fax number: (919) 541-0840; email address: 
morris.mark@epa.gov. For information about the applicability of these 
three NESHAP to a particular entity, contact Ms. Tavara Culpepper, 
Office of Enforcement and Compliance Assurance (OECA), telephone 
number: (202) 564-0902; email address: culpepper.tavara@epa.gov.

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:

ACGIH American Conference of Governmental Industrial Hygienists
ADAF age-dependent adjustment factors
AEGL acute exposure guideline levels
AERMOD air dispersion model used by the HEM-3 model
AMF Acrylic and Modacrylic Fibers
APR Amino/Phenolic Resins
BACT best available control technology
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
EJ environmental justice
EPA Environmental Protection Agency
ERPG Emergency Response Planning Guidelines
ERT Electronic Reporting Tool
FR Federal Register
GACT generally achievable control technology
HAP hazardous air pollutants
HCl hydrochloric acid
HEM-3 Human Exposure Model, Version 1.1.0
HI hazard index
HON National Emission Standards for Organic Hazardous Air Pollutants 
From the Synthetic Organic Chemical Manufacturing Industry
HQ hazard quotient
ICR Information Collection Request
IRIS Integrated Risk Information System
km kilometer
LAER lowest achievable emission rate
LDAR leak detection and repair
MACT maximum achievable control technology
MACT Code Code within the NEI used to identify processes included in 
a source category
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
NEI National Emissions Inventory
NESHAP National Emissions Standards for Hazardous Air Pollutants
NIOSH National Institutes for Occupational Safety and Health
NRC National Research Council
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OECA Office of Enforcement and Compliance Assurance
OMB Office of Management and Budget
PAH polycyclic aromatic hydrocarbons
PB-HAP hazardous air pollutants known to be persistent and bio-
accumulative in the environment
PC Polycarbonate
POM polycyclic organic matter
ppm parts per million
PRD pressure relief device
RACT reasonably available control technology
RBLC RACT/BACT/LAER Clearinghouse
REL reference exposure level
RFA Regulatory Flexibility Act
RfC reference concentration
RfD reference dose
RTO regenerative thermal oxidizer
RTR residual risk and technology review
SAB Science Advisory Board
SBA Small Business Administration
SOCMI Synthetic Organic Chemical Manufacturing Industry
SOP standard operating procedures
SSM startup, shutdown and malfunction
TEQ toxic equivalency quotient
TLV threshold limit value
TOSHI target organ-specific hazard index
tpy tons per year
TRIM.FaTE Total Risk Integrated Methodology.Fate, Transport, and 
Ecological Exposure model
TTN Technology Transfer Network
UF uncertainty factor
[mu]g/m\3\ microgram per cubic meter
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
VCS voluntary consensus standards
VOC volatile organic compounds

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

I. General Information
    A. Executive Summary
    B. Does this action apply to me?
    C. Where can I get a copy of this document and other related 
information?
    D. What should I consider as I prepare my comments for the EPA?
    E. Public Hearing
II. Background
    A. What is the statutory authority for this action?
    B. What are the source categories and how did the MACT standards 
regulate their HAP emissions?
    C. What data collection activities were conducted to support 
this action?
    D. What other relevant background information and data are 
available?
III. Analytical Procedures
    A. How did we estimate post-MACT risks posed by the source 
categories?
    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 for the AMF Source 
Category
    A. What actions are we taking pursuant to CAA sections 112(d)(2) 
and 112(d)(3)?
    B. What are the results of the risk assessment and analyses?
    C. What are our proposed decisions regarding risk acceptability, 
ample margin of safety and adverse environmental effects?
    D. What are the results and proposed decisions based on our 
technology review?
V. Analytical Results and Proposed Decisions for the APR Source 
Category
    A. What actions are we taking pursuant to CAA sections 112(d)(2) 
and 112(d)(3)?
    B. What are the results of the risk assessment and analyses?
    C. What are our proposed decisions regarding risk acceptability, 
ample margin of safety and adverse environmental effects?
    D. What are the results and proposed decisions based on our 
technology review?
VI. Analytical Results and Proposed Decisions for the PC Source 
Category
    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 and proposed decisions based on our 
technology review?
VII. What other actions are we proposing?
    A. Startup, Shutdown and Malfunction
    B. Electronic Reporting
    C. Open-Ended Valves and Lines
    D. Flare Performance
VIII. What compliance dates are we proposing?
IX. 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?
X. Request for Comments

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XI. Submitting Data Corrections
XII. 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-2012-0133).

I. General Information

A. Executive Summary

1. Purpose of the Regulatory Action
    Section 112(d)(1) of the CAA requires the EPA to establish NESHAP 
for source categories and subcategories of both major sources and area 
sources of HAP that are listed for regulation under CAA section 112(c). 
For major sources of HAP, under CAA sections 112(d)(2) and (3), the EPA 
is required to set standards that reflect the emissions performance 
achieved by the maximum achievable control technology (MACT) and by 
other measures used at sources in the subject source category. For area 
sources, under CAA section 112(d)(5) the EPA is allowed to instead 
adopt standards reflecting generally achievable control technology 
(GACT). Section 112(d)(6) of the CAA requires the EPA to review these 
NESHAP regulations for each covered source category and to revise them 
as necessary (taking into account developments in practices, processes 
and control technologies) no less frequently than every 8 years. 
Section 112(f)(2) of the CAA requires the EPA to assess, within 8 years 
of promulgation of the original NESHAP for major sources and area 
sources subject to MACT, the remaining risks due to emissions of HAP 
from these source categories and determine whether the emissions 
standards provide an ample margin of safety to protect public health. 
Section 112(f)(5) provides that the EPA is not required to conduct this 
latter review for area sources subject to GACT. We refer to these 
reviews collectively as residual risk and technology reviews (RTRs).
    This action presents the results of, and proposed decisions based 
on, the EPA's reviews of the following three source categories: Acrylic 
and Modacrylic Fibers Production (AMF), Amino/Phenolic Resins 
Production (APR) and Polycarbonate Production (PC). As detailed below, 
the EPA is proposing amendments, based on the relevant RTR, to 
regulations applicable to each of these three source categories. In 
addition, we are also proposing amendments to the relevant regulations 
to address the following: Emissions during periods of startup, shutdown 
and malfunction; standards for previously unregulated HAP emissions 
sources; revisions to require monitoring of pressure relief devices in 
organic HAP service that release to the atmosphere; clarification of 
provisions pertaining to open-ended valves and lines; and revisions to 
require electronic reporting of performance test results.
2. Summary of the Major Provisions of the Regulatory Action in Question
    With regard to the AMF source category, the EPA has determined that 
no amendments are needed for this source category based on the risk 
review under CAA section 112(f). However, based on the technology 
review under CAA section 112(d)(6), the EPA is proposing to eliminate 
the less stringent of two currently available options for complying 
with leak detection and repair program requirements--while retaining 
the more stringent compliance requirement. In addition, under CAA 
sections 112(d)(2) and (3), the EPA is proposing requirements to 
address certain emission points that were not previously regulated.
    With regard to the APR source category, the EPA has determined that 
no amendments are needed for this source category based on the risk and 
technology reviews under CAA sections 112(d)(6) and 112(f). However, 
under CAA sections 112(d)(2) and (3), the EPA is proposing requirements 
to address certain emission points that were not previously regulated.
    With regard to the PC source category, the EPA has determined that 
no amendments are needed for this source category based on the risk 
review under CAA section 112(f). However, based on the technology 
review under CAA section 112(d)(6), the EPA is proposing to eliminate 
the less stringent of two currently available options for complying 
with leak detection and repair program requirements--while retaining 
the more stringent compliance requirement.
    The EPA is also proposing revisions to all three source categories 
in four areas. First, the EPA is proposing to revise the standards so 
that they apply at all times, including during periods of startup, 
shutdown and malfunction (SSM). Second, the EPA is proposing to require 
electronic reporting of performance test results. Third, the EPA is 
clarifying the provisions regarding open-ended lines by adding a 
definition for what constitutes a ``sealed'' open-ended line. Finally, 
the EPA is proposing to require monitoring of pressure relief devices 
(PRDs) in organic HAP service that release to the atmosphere, and that 
a pressure release from such a PRD is a violation.
3. Costs and Emissions Reductions
    Table 1 below summarizes the estimated costs and potential 
emissions reductions for this action. See section IX of this preamble 
for further discussion of the costs and impacts.

      Table 1--Summary of the Costs and Emissions Reductions for the Proposed Acrylic and Modacrylic Fibers
           Production, Amino/Phenolic Resins Production and Polycarbonate Production NESHAP Amendments
----------------------------------------------------------------------------------------------------------------
                                                      Number                                         Emissions
                 Source category                     affected      Capital costs    Annualized      reductions
                                                      plants            ($)        costs  ($/yr)       (tpy)
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Acrylic and Modacrylic Fibers Production........               1         $38,000          $6,000             0.2
Amino/Phenolic Resins Production................              18       1,500,000         400,000            20.1
Polycarbonate Production........................               4          67,000           9,400             2.1
----------------------------------------------------------------------------------------------------------------

[[Page 1679]]

B. Does this action apply to me?

    Table 2 of this preamble lists the NESHAP and associated regulated 
industrial source categories that are the subject of this proposal. 
Table 2 is not intended to be exhaustive, but rather to provide a guide 
for readers regarding entities that this proposed action is likely to 
affect. The proposed standards, once finalized, will be directly 
applicable to the affected sources. Federal, state, local and tribal 
government entities would not be affected by this proposed action. As 
defined in the ``Initial List of Categories of Sources Under Section 
112(c)(1) of the Clean Air Act Amendments of 1990'' (see 57 FR 31576, 
July 16, 1992), the ``Acrylic and Modacrylic Fibers Production'' source 
category includes any facility engaged in manufacturing fibers in which 
the fiber-forming substance is any long-chain, synthetic polymer 
composed of at least 85 percent, by weight, acrylonitrile units. As 
defined in the ``Initial List of Categories of Sources Under Section 
112(c)(1) of the Clean Air Act Amendments of 1990'' (see 57 FR 31576, 
July 16, 1992) and subsequently amended (see 65 FR 3276, January 20, 
2000), the ``Amino/Phenolic Resins Production'' source category 
includes any facility engaged in manufacturing amino resins or phenolic 
resins. As defined in the ``Initial List of Categories of Sources Under 
Section 112(c)(1) of the Clean Air Act Amendments of 1990'' (see 57 FR 
31576, July 16, 1992), the ``Polycarbonate Production'' source category 
includes any facility which manufactures a special class of polyester 
formed from the dihydroxy compound and any carbonate diester or by 
ester interchange.

    Table 2--NESHAP and Industrial Source Categories Affected by This
                             Proposed Action
------------------------------------------------------------------------
 
------------------------------------------------------------------------
               NESHAP and source category                 NAICS Code \a\
------------------------------------------------------------------------
Generic Maximum Achievable         Acrylic and                    325220
 Control Technology Standards.      Modacrylic Fibers           (325222)
                                    Production.
                                   Polycarbonate                  325211
                                    Production.                 (325211)
------------------------------------------------------------------------
Amino/Phenolic Resins Production                                  325211
                                                                (325211)
------------------------------------------------------------------------
\a\ North American Industry Classification System 2012 (2007 in
  parenthesis).

C. 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 proposal 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. The TTN 
provides information and technology exchange in various areas of air 
pollution control. 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 sites: http://www.epa.gov/ttn/atw/gmact/gmactpg.html and http://www.epa.gov/ttn/atw/amino/aminopg.html. Information on the overall residual risk and technology 
review program is available at the following Web site: http://www.epa.gov/ttn/atw/rrisk/rtrpg.html.

D. 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: Nick 
Parsons, c/o OAQPS Document Control Officer (C404-02), Office of Air 
Quality Planning and Standards, U.S. Environmental Protection Agency, 
Research Triangle Park, North Carolina 27711, Attn: Docket ID No. EPA-
HQ-OAR-2012-0133.

E. Public Hearing

    If a hearing is held, it will provide interested parties the 
opportunity to present data, views or arguments concerning the proposed 
action. The EPA will make every effort to accommodate all speakers who 
arrive and register. Because this hearing, if held, will be at a U.S. 
governmental facility, individuals planning to attend the hearing 
should be prepared to show valid picture identification to the security 
staff in order to gain access to the meeting room. In addition, you 
will need to obtain a property pass for any personal belongings you 
bring with you. Upon leaving the building, you will be required to 
return this property pass to the security desk. No large signs will be 
allowed in the building, cameras may only be used outside of the 
building and demonstrations will not be allowed on federal property for 
security reasons. The EPA may ask clarifying questions during the oral 
presentations but will not respond to the presentations at that time. 
Written statements and supporting information submitted during the 
comment period will be considered with the same weight as oral comments 
and supporting information presented at the public hearing. If a 
hearing is held on February 10, 2014, written comments on the proposed 
rule must be postmarked by March 10, 2014. Commenters should notify Ms. 
Virginia Hunt if they will need specific equipment, or if there are 
other special needs related to providing comments at the hearing. The 
EPA will provide equipment for commenters to show overhead slides or 
make computerized slide presentations if we receive special requests in 
advance. Oral testimony will be limited to 5 minutes for each

[[Page 1680]]

commenter. The EPA encourages commenters to provide the EPA with a copy 
of their oral testimony electronically (via email or CD) or in hard 
copy form. Verbatim transcripts of the hearings and written statements 
will be included in the docket for the rulemaking. The EPA will make 
every effort to follow the schedule as closely as possible on the day 
of the hearing; however, please plan for the hearing to run either 
ahead of schedule or behind schedule. Information regarding the hearing 
(including information as to whether or not one will be held) will be 
available at: http://www.epa.gov/ttn/oarpg/t3main.html. Again, all 
requests for a public hearing to be held must be received by January 
24, 2014.

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 HAP 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 emissions reductions of HAPs 
achievable (after considering cost, energy requirements and non-air 
quality health and environmental impacts) and are commonly referred to 
as MACT standards.
    MACT standards must require 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 
emission 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 that either: (1) a pollutant cannot be emitted through a 
conveyance designed and constructed to emit or capture the pollutants 
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-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 
emissions reductions, any non-air quality health and environmental 
impacts and energy requirements.
    The EPA is then 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). 
This provision requires, first, that the EPA 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. Congress did 
not act in response, thereby triggering the EPA's obligation under CAA 
section 112(f)(2) to analyze and address residual risk.
    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.

[[Page 1681]]

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.'' Id. 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 
(DC 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 38045. 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 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 approach 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 38046.
    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 (DC 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,\1\ but must consider cost, energy, safety 
and other relevant factors in doing so.
---------------------------------------------------------------------------

    \1\ ``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 38044-38045, 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

[[Page 1682]]

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 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.

B. What are the source categories and how did the MACT standards 
regulate their HAP emissions?

1. Acrylic and Modacrylic Fibers Production Source Category
    The NESHAP for Acrylic and Modacrylic Fibers Production (``AMF MACT 
standards''), with the exception of wastewater processes, were 
promulgated on June 29, 1999 (64 FR 34854), and codified at 40 CFR part 
63, subpart YY. The provisions for wastewater were promulgated 
separately on November 22, 1999 (64 FR 63695), and also codified at 40 
CFR part 63, subpart YY. The AMF MACT standards were established in a 
consolidated rulemaking for certain small source categories consisting 
of five or fewer major sources. The standards for these source 
categories were developed under the EPA's Generic MACT program.
    Acrylic and modacrylic fibers are manufactured fibers in which the 
fiber-forming substance is a long-chain synthetic polymer containing 
acrylonitrile units. The fiber-forming substance in acrylic fibers is 
composed of at least 85 percent acrylonitrile units by weight, whereas 
modacrylic fibers are less than 85 but at least 35 percent 
acrylonitrile units by weight. These acrylic and modacrylic fibers have 
been used in textiles (including apparel, carpet, awnings, tents, 
sandbags and auto upholstery) and in industrial applications like 
concrete reinforcements and industrial filters. These fibers are also 
used as carbon fiber precursors. Carbon fibers developed from acrylic 
fibers have high tensile strength and are used in aerospace 
applications, such as aircraft airframes and engine structures, as well 
as other applications where light weight and high strength are needed, 
including racing car bodies, golf club shafts, bicycle frames, fishing 
rods, automobile springs, sailboat masts and many other items.
    The production of AMF involves a polymerization reaction process 
using either a solution or suspension process in either a batch or 
continuous mode. The resulting polymer (called ``spin dope'') is spun 
into fibers using either wet or dry spinning techniques. The spun 
fibers are then treated to remove excess solvent and to improve fiber 
characteristics through processes such as washing, stretching, crimping 
and drying.
    Sources of HAP emissions from the production of AMF include: (1) 
Storage vessels used to store acrylonitrile monomer and co-monomers; 
(2) process vents on reactors, vessels and storage vessels used for 
acrylic polymerization, monomer recovery, fiber spinning and solvent 
recovery operations; (3) fugitive emissions from AMF spinning lines; 
(4) wastewater treatment systems; and (5) equipment leaks. In the 
production of AMF, HAP are used primarily as raw materials or reaction 
inhibitors in the polymerization reaction process. The AMF MACT 
standards include emission limits for existing and new fiber spinning 
lines using spin dope from a suspension polymerization process, new 
sources using a solution polymerization process and for process vents 
at all facilities. The AMF MACT standards include a combination of 
equipment standards and work practices for equipment leaks and 
wastewater, and a combination of equipment standards and emission 
limits for storage vessels.
    To meet the requirements of the AMF MACT standards, the emissions 
from storage vessels are typically controlled either by floating roofs 
or fixed roofs that route emissions through a closed vent system to a 
combustion or recovery device. Emissions from wastewater are generally 
controlled by equipment modifications (e.g., covers on surface 
impoundments, containers and drain systems) and pretreatment to remove 
HAP and biodegradation or pretreatment and discharge to a publicly 
owned treatment works for biodegradation. Emissions from equipment 
leaks are typically reduced by leak detection and repair (LDAR) work 
practice programs. Controls for process vents include combustion or 
recovery devices, and controls for fiber spinning lines include 
enclosure of the spinning and washing areas with venting to a 
combustion or recovery device.
    We identified one major source currently operating that is subject 
to the AMF MACT standards. Acrylonitrile accounts for the majority of 
the HAP emissions from the AMF processes at this facility 
(approximately 32 tpy and over 99 percent of the total HAP emissions by 
mass). The only other HAP reported by this facility is hydroquinone 
(approximately 3 lbs/yr). As we have stated previously, other organic 
HAP, where present, would only be associated with those pollutant 
streams containing acrylonitrile, and where sources control 
acrylonitrile emissions, comparable levels of control will be achieved 
for other organic HAP emitted from AMF facilities. See NESHAP: Generic 
Maximum Achievable Control Technology (Generic MACT); Final Rule, 
Process Wastewater Provisions; Proposed Rule, 64 FR 34854, 34858 (June 
29, 1999). The same is true here--hydroquinone is emitted only from 
equipment leaks, and equipment leaks are already subject to control 
through the LDAR program in the rule.
    We estimate that the actual emissions levels for all emission 
sources are representative of the MACT-allowable levels (i.e., the 
maximum emission levels allowed if in compliance with the MACT 
standards), as we are not aware of any situations in which the facility 
is conducting additional work practices or operating a control device 
such that it achieves a greater emission reduction than required. For 
more detail about this estimate of the ratio of actual-to-MACT-
allowable emissions and the estimation of the MACT-allowable emission 
levels (and associated risks and impacts), see the memorandum, MACT 
Allowable Emissions and Risks for the Acrylic and Modacrylic Fibers, 
Amino/Phenolic Resins, and Polycarbonate Production Source Categories, 
available in the docket for this action (EPA-HQ-OAR-2012-0133).
2. Amino/Phenolic Resins Production
    The NESHAP for the Manufacture of Amino/Phenolic Resins (``APR MACT 
standards''; also referred to as Group III Polymers and Resins) were 
promulgated on January 20, 2000 (65 FR 3275), and codified at 40 CFR 
part 63, subpart OOO. The APR MACT standards apply to major sources and 
regulate HAP emissions resulting from the manufacture of amino resins 
or phenolic resins. These two products can broadly be classified as 
formaldehyde-based thermosetting resins. An amino resin is a resin 
produced through the reaction of formaldehyde, or a formaldehyde-
containing solution, with one or more compounds that contain an amino 
group; these compounds include melamine, urea and urea derivatives. A 
phenolic resin is a resin that is a condensation product of 
formaldehyde and phenol, or a formaldehyde substitute and/or a phenol 
substitute.

[[Page 1683]]

Substitutes for formaldehyde include acetaldehyde or furfuraldehyde. 
Substitutes for phenol include other phenolic-starting compounds such 
as cresols, xylenols, p-tert-butylphenol, p-phenylphenol and 
nonylphenol. Formaldehyde, phenol, acetaldehyde and cresols are HAP, 
but the other reactants are not. Amino/phenolic resins are used in the 
manufacture of plywood, particle board, adhesives, wood furniture and 
plastic parts.
    Generally, the production of APR entails four processes: (1) Raw 
material (i.e., solvent and catalyst) storage and refining; (2) polymer 
formation in a reactor; (3) material recovery; and (4) finishing (e.g., 
cooling, filtering, drying or pulverizing).
    Sources of HAP emissions from the production of APR include reactor 
batch process vents, non-reactor batch process vents, continuous 
process vents, equipment leaks, wastewater, storage vessels and heat 
exchangers. In the production of APR, HAP are used primarily as 
reactants or extraction solvents. The APR MACT standards include a 
combination of equipment standards and emission limits for the various 
emission sources.
    To meet the requirements of the APR MACT standards, the typical 
control techniques used to reduce emissions include LDAR programs for 
heat exchangers and other equipment. Boilers, combustion and recovery 
devices may be used to control emissions from batch process vents.
    We identified 18 currently-operating facilities subject to the APR 
MACT standards. Methanol, formaldehyde and phenol account for the 
majority of the HAP emissions from the APR production processes at 
these facilities (approximately 357 tpy and 96 percent of the total HAP 
emissions by mass). A variety of other chemicals are used in the 
production of APR, and these facilities also reported emissions of 23 
other HAP. Emissions of three persistent bioaccumulative HAP (PB-HAP) 
are reported in the data set for this source category, including lead 
compounds, cadmium compounds, and polycyclic organic matter (POM) 
(which includes polyaromatic hydrocarbons (PAH)).
    We estimate that the actual emissions levels for all sources are 
representative of the MACT-allowable levels (i.e., the maximum emission 
levels allowed if in compliance with the MACT standards), as we are not 
aware of any situations in which facilities are conducting additional 
work practices or operating a control device such that it achieves a 
greater emission reduction than required, except batch process vents. 
As it is possible that the capture systems and control devices used at 
some facilities achieve greater emission reductions than what is 
required by the NESHAP for batch process vents, the MACT-allowable 
level for organic HAP emissions from reactor batch process vents could 
be up to 3.4 times the actual emissions and the MACT-allowable level 
for organic HAP emissions from non-reactor batch process vents could be 
up to 1.6 times the actual emissions for some facilities in this source 
category. For more detail about this estimate of the ratio of actual-
to-MACT-allowable emissions and the estimation of MACT-allowable 
emission levels (and associated risks and impacts), see the memorandum, 
MACT Allowable Emissions and Risks for the Acrylic and Modacrylic 
Fibers, Amino/Phenolic Resins, and Polycarbonate Production Source 
Categories, available in the docket for this action (EPA-HQ-OAR-2012-
0133).
3. Polycarbonate Production Source Category
    The NESHAP for Polycarbonate Production (``PC MACT standards''), 
with the exception of wastewater processes, were promulgated on June 
29, 1999 (64 FR 34854), and codified at 40 CFR part 63, subpart YY. The 
provisions for wastewater were promulgated separately on November 22, 
1999 (64 FR 63695), and also codified at 40 CFR part 63, subpart YY. 
Along with the AMF and other source categories, the PC source category 
standards were established in a consolidated rulemaking for certain 
small source categories consisting of five or fewer major sources. The 
standards for these source categories were developed under the EPA's 
Generic MACT program.
    Polycarbonates are thermoplastic polymers that can be either 
transparent or opaque, are heat resistant and are scratch and impact 
resistant. These properties make PC useful in a variety of 
applications, including as a dielectric in capacitors, car headlights, 
water bottles, sports helmets, compact discs and DVDs, eyewear lenses, 
medical devices, toys and other products.
    The production of PC involves a polymerization reaction process 
using either a solution or suspension process in either a batch or 
continuous mode. All production of PC in the United States is currently 
based on the polymerization reaction of bisphenols with phosgene in the 
presence of catalysts, solvents (mainly methylene chloride) and other 
additives. After the reaction, the resulting polymer is purified and 
sent to a recovery process to remove remaining methylene chloride. The 
resin is dried and stored in silos.
    All phosgene used as a feedstock for the production of PC is 
produced onsite to reduce potential hazards associated with 
transporting and storing this material. The phosgene is fed directly 
from dedicated phosgene production equipment to PC polymerization 
process equipment. Consequently, phosgene production is integrated with 
the production of PC; the production of PC cannot occur without the 
other process operating. Since dedicated phosgene production units are 
integral to the PC production process, the EPA considers such phosgene 
production units to be part of the PC source category (63 FR 55178, 
October 18, 1998).
    Sources of HAP emissions from the production of PC include storage 
vessels used to store methylene chloride and other organic solvents; 
process vents on polymerization, polymer solution purification and 
solvent recovery equipment; wastewater treatment systems; and equipment 
leaks. In the production of PC, HAP are used as monomers, co-monomers 
and solvents in the polymerization reaction. The PC MACT standards 
include emission limits for continuous process vents. The PC MACT 
standards include a combination of equipment standards and work 
practices for equipment leaks and wastewater and a combination of 
equipment standards and emission limits for storage vessels.
    To meet the requirements of the PC MACT standards, the typical 
control devices used to reduce emissions from storage vessels are fixed 
roofs with emissions routed through a closed vent system to a 
combustion or recovery device. Emissions from wastewater are generally 
controlled by equipment modifications (e.g., covers on surface 
impoundments, containers and drain systems) and treatment to remove the 
HAP, including steam stripping followed by recovery or combustion of 
the stripped HAP. Emissions from equipment leaks are typically reduced 
by leak detection and repair work practice programs. Controls for 
continuous and batch process vents include combustion or recovery 
devices.
    We identified four currently-operating facilities subject to the PC 
MACT standards. Methylene chloride, ethyl chloride and triethylamine 
account for the majority of the HAP emissions from the PC production 
processes at these facilities (approximately 330 tpy and over 99 
percent of the total HAP emissions by mass). Phosgene and chlorobenzene 
emissions were also reported from the PC production processes at these 
facilities.

[[Page 1684]]

    We estimate that the actual emissions levels for all sources are 
representative of the MACT-allowable levels (i.e., the maximum emission 
levels allowed if in compliance with the MACT standards), as we are not 
aware of any situations in which facilities are conducting additional 
work practices or operating a control device such that it achieves a 
greater emission reduction than required, except storage vessels. As it 
is possible that the capture systems and control devices used at some 
facilities achieve greater HAP emission reductions than what is 
required by the NESHAP for some storage vessels, depending on the 
vessel capacity and vapor pressure of the stored material, the MACT-
allowable level of HAP emissions could be up to 2.5 times the actual 
emissions for storage vessels in this source category. For more detail 
about this estimate of the ratio of actual to MACT-allowable emissions 
and the estimation of the MACT-allowable emission levels (and 
associated risks and impacts), see the memorandum, MACT Allowable 
Emissions and Risks for the Acrylic and Modacrylic Fibers, Amino/
Phenolic Resins, and Polycarbonate Production Source Categories, 
available in the docket for this action (EPA-HQ-OAR-2012-0133).

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

    To perform the risk assessments for these source categories, we 
developed data sets for the APR and PC source categories based on 
information in the 2005 National Emissions Inventory (NEI) (available 
at http://www.epa.gov/ttnchie1/net/2005inventory.html). 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. We reviewed the NEI 
data and made adjustments where necessary to ensure the proper 
facilities were included and to ensure the proper processes were 
allocated to each source category. We also reviewed the emissions and 
other data to identify data anomalies that could affect risk estimates, 
such as whether a pollutant was expected to be emitted from facilities 
in a source category or whether an emission point was located within a 
facility's fenceline. The NEI data were also reviewed by industry trade 
groups, including the American Chemistry Council and the Society of 
Chemical Manufacturers and Affiliates, as well as several state air 
agencies. Where the EPA received new information from the industry and 
air agency review, including updated emissions data and process 
information, facility closure information and information that some 
facilities were not subject to the APR or PC MACT standards, we revised 
the NEI data where we concluded the comments supported such adjustment. 
We used this reviewed and revised data set to conduct the risk 
assessment and other analyses for each source category. Due to the 
conservative nature of our emissions estimates, as described in the 
emissions data memo cited below, we believe that the data set provides 
a conservative estimate for use in assessing the risk from these source 
categories. Further details on the changes made to the 2005 NEI data 
can be found in the memorandum, Emissions Data and Acute Risk Factor 
Used in Residual Risk Modeling: Acrylic and Modacrylic Fibers, Amino/
Phenolic Resins, and Polycarbonate Production, available in the docket 
for this action (EPA-HQ-OAR-2012-0133).
    To perform the risk assessment for the AMF source category, we 
developed a data set based on information submitted to the EPA for this 
purpose by the one operating facility in the source category. On 
February 23, 2012, the EPA visited this facility, Cytec Carbon Fibers, 
LLC, located in Piedmont, South Carolina. The purpose of this visit was 
to better understand the acrylic fiber production processes, the 
controls in place to reduce HAP emissions and the characteristics of 
the emission points at this facility. As part of this visit, the EPA 
requested that facility personnel examine the 2008 NEI HAP inventory 
data that the EPA had for the facility. The EPA provided this data to 
the facility prior to the site visit to give the facility the 
opportunity to correct or update the data. After review of the data, 
the facility submitted updated information, and the updated data formed 
the basis for the data set used for modeling.

D. What other relevant background information and data are available?

    To conduct the technology review, we reviewed information developed 
since these rules were originally promulgated in 1999 and 2000. Since 
those rules have been promulgated, the EPA has developed other air 
toxics regulations for a number of other source categories that emit 
organic HAP from the same type of emission sources that are present in 
the three source categories included in this technology review. In 
these other air toxic regulatory actions, we consistently evaluated any 
new practices, processes and control techniques. For this technology 
review, we took into account the regulatory requirements and/or 
technical analyses associated with these other regulatory actions to 
identify any practices, processes and control techniques considered in 
these efforts that could possibly be applied to the source categories 
addressed in this action.
    We also downloaded from the reasonably available control technology 
(RACT)/best available control technology (BACT)/lowest achievable 
emission rate (LAER) Clearinghouse for processes in the AMF, APR and PC 
source categories with permits dating back to the promulgation dates of 
each MACT regulation. Finally, we conducted an online search of all 
relevant publications, journals, permits and other documents to 
identify any new practices, processes or control technologies for HAP 
emissions sources since the dates of promulgation of the standards.
    To evaluate unregulated emission points at facilities regulated by 
the APR MACT standards, we relied on existing data submitted to the EPA 
during development of the existing APR MACT standards. To evaluate 
unregulated emission points for the AMF MACT standards, we relied 
primarily on data submitted to the EPA by the one operating facility in 
the source category, along with information gathered during the EPA's 
visit to the facility.

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 categories?

    The EPA conducted risk assessments that provided estimates of the 
MIR posed by the HAP emissions from each source in each 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 assessments also provided estimates of the 
distribution of cancer risks within the exposed populations, cancer 
incidence and an evaluation of the potential for adverse environmental 
effects for each source category. The risk assessment consisted of 
eight primary steps, as discussed below. The docket for this rulemaking 
contains the following documents which provide more

[[Page 1685]]

information on the risk assessment inputs and models: Draft Residual 
Risk Assessment for the Acrylic and Modacrylic Fibers Production Source 
Category, Draft Residual Risk Assessment for the Amino/Phenolic Resins 
Production Source Category, and Draft Residual Risk Assessment for the 
Polycarbonate Production 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 
\2\; they are also consistent with the key recommendations contained in 
that report.
---------------------------------------------------------------------------

    \2\ 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?
    As discussed in section II.C of this preamble, we created the 
preliminary data sets for the APR and PC source categories using data 
in the 2005 NEI, supplemented by data collected from industry, industry 
trade associations and state air agencies (when available). For the AMF 
source category, we used data collected from the one facility subject 
to the AMF MACT standards.
2. How did we estimate MACT-allowable emissions?
    The available emissions data in the MACT 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.)
    As described above, the actual emissions data were compiled based 
on the NEI and information gathered from facilities through industrial 
trade associations and state air agencies for the APR and PC source 
categories and through the one facility subject to the AMF MACT 
standards. To estimate emissions at the MACT-allowable level, we 
developed a ratio of MACT-allowable to actual emissions for each 
emissions source type in each source category, based on the level of 
control required by the MACT standards compared to the level of 
reported actual emissions and available information on the level of 
control achieved by the emissions controls in use. For example, if 
there was information to suggest several facilities in a source 
category were controlling storage tank emissions by 98 percent while 
the MACT standards required only 92-percent control, we would estimate 
that MACT-allowable emissions from these emission points could be as 
much as four times higher (8-percent allowable emissions compared with 
2 percent actually emitted), and the ratio of MACT-allowable to actual 
would be 4:1 for this emission point type at the facilities in this 
source category. After developing these ratios for each emission point 
type in each source category, we next applied these ratios on a 
facility-by-facility basis to the maximum chronic risk values from the 
inhalation risk assessment to obtain facility-specific maximum risk 
values based on MACT-allowable emissions. Further explanation of this 
evaluation is provided in the technical document, MACT Allowable 
Emissions and Risks for the Acrylic and Modacrylic Fibers, Amino/
Phenolic Resins, and Polycarbonate Production Source Categories, 
available in the docket for this action (EPA-HQ-OAR-2012-0133).
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 categories 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 \3\; and (3) estimating 
individual and population-level inhalation risks using the exposure 
estimates and quantitative dose-response information.
---------------------------------------------------------------------------

    \3\ 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.\4\ 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 of hourly 
surface and upper air observations for 189 meteorological stations, 
selected to provide coverage of the United States and Puerto Rico. A 
second library of United States Census Bureau census block \5\ 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.
---------------------------------------------------------------------------

    \4\ 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).
    \5\ A census block is generally 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 concentration 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

[[Page 1686]]

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.
    With regard to formaldehyde (one of the primary HAP emitted by 
facilities in the APR source category), the EPA determined in 2004 that 
the Chemical Industry Institute of Toxicology (CIIT) cancer dose-
response value for formaldehyde (5.5 x 10-9 per mg/m\3\) was 
based on better science than the IRIS cancer dose-response value (1.3 x 
10-5 per mg/m\3\). Thus, we switched at that time from using 
the IRIS value to the CIIT value in risk assessments supporting 
regulatory actions. Based on subsequent published research, however, 
the EPA changed its determination regarding the CIIT model and, in 
2010, the EPA returned to using the 1991 IRIS value. The EPA has been 
working on revising the formaldehyde IRIS assessment, and the National 
Academy of Sciences (NAS) completed its review of the EPA's draft in 
April of 2011.\6\ The EPA is reviewing the public comments and the NAS 
independent scientific peer review. The EPA will follow the NAS Report 
recommendations and will present results obtained by implementing the 
biologically-based dose-response (BBDR) model for formaldehyde. The EPA 
will compare these estimates with those currently presented in the 
External Review draft of the assessment and will discuss their 
strengths and weaknesses. As recommended by the NAS committee, 
appropriate sensitivity and uncertainty analyses will be an integral 
component of implementing the BBDR model. The draft IRIS assessment 
will be revised in response to the NAS peer review, and public comments 
and the final assessment will be posted on the IRIS database. In the 
interim, we will present findings using the 1991 IRIS value as a 
primary estimate, and may also consider other information as the 
science evolves. As noted above and described in the risk assessment, 
the IRIS URE for formaldehyde is 1.3 x 10-5 mg/m\3\, 
whereas, the CIIT URE for formaldehyde is 5.5 x 10-9 mg/
m\3\.
---------------------------------------------------------------------------

    \6\ http://www.nap.edu/catalog.php?record_id=13142.
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    We note here that several carcinogens have a mutagenic mode of 
action.\7\ Of these compounds, POM is emitted by facilities in the APR 
source category. For these compounds, the age-dependent adjustment 
factors (ADAF) described in the EPA's Supplemental Guidance for 
Assessing Susceptibility from Early-Life Exposure to Carcinogens \8\ 
were applied. This adjustment has the effect of increasing the 
estimated lifetime risks for these pollutants by a factor of 1.6.\9\ In 
addition, the EPA expresses carcinogenic potency for compounds in the 
POM group in terms of benzo[a]pyrene equivalence, based on evidence 
that carcinogenic POM have the same mutagenic mechanism of action as 
does benzo[a]pyrene. For this reason, the EPA's Science Policy Council 
\10\ recommends applying the Supplemental Guidance to all carcinogenic 
polycyclic aromatic hydrocarbons for which risk estimates are based on 
relative potency. Accordingly, we have applied the ADAF to 
benzo[a]pyrene equivalent portion of all POM mixtures.
---------------------------------------------------------------------------

    \7\ U.S. EPA, 2006. Performing risk assessments that include 
carcinogens described in the Supplemental Guidance as having a 
mutagenic mode of action. Science Policy Council Cancer Guidelines 
Implementation Workgroup Communication II: Memorandum from W.H. 
Farland dated June 14, 2006. http://epa.gov/osa/spc/pdfs/CGIWGCommunication_II.pdf.
    \8\ U.S. EPA, 2005. Supplemental Guidance for Assessing Early-
Life Exposure to Carcinogens. EPA/630/R-03/003F. http://www.epa.gov/ttn/atw/childrens_supplement_final.pdf.
    \9\ Only one of these mutagenic compounds, benzo[a]pyrene, is 
emitted by any of the sources covered by this proposal.
    \10\ U.S. EPA, 2005. Science Policy Council Cancer Guidelines 
Implementation Workgroup Communication I: Memorandum from W.H. 
Farland dated October 4, 2005, to Science Policy Council. http://www.epa.gov/osa/spc/pdfs/canguid1.pdf.
---------------------------------------------------------------------------

    The EPA estimated incremental individual lifetime cancer risks 
associated with emissions from the facilities in the source categories 
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 \11\) 
emitted by the modeled sources. Cancer incidence and the distribution 
of individual cancer risks for the population within 50 km of any 
source were also estimated for the source categories as part of these 
assessments by summing individual risks. A distance of 50 km is 
consistent with both the analysis supporting the 1989 Benzene NESHAP 
(54 FR 38044) and the limitations of Gaussian dispersion models, 
including AERMOD.
---------------------------------------------------------------------------

    \11\ 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 SAB in their 2002 peer review of the 
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 level, 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 cubic 
meter ([mu]g/m\3\) for inhalation exposure and in a dose expressed in 
units of milligram per kilogram-day (mg/kg-day) for oral exposures), at 
or

[[Page 1687]]

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) emission rates 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 emission 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 value 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/opptintr/aegl/pubs/sop.pdf),\12\ ``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.
---------------------------------------------------------------------------

    \12\ 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 nonregulatory 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/m\3\ 
(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 nonsensory 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 nondisabling odor, 
taste, and sensory irritation or certain asymptomatic, nonsensory 
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.'' \13\ 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.
---------------------------------------------------------------------------

    \13\ 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 result when basing them on the acute

[[Page 1688]]

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.\14\ 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 these 
source categories, a factor of 10 was applied to all emissions, with 
one exception. A factor of two was applied for emissions from equipment 
leaks for all three source categories. A further discussion of why 
these factors were chosen can be found in the memorandum, Emissions 
Data and Acute Risk Factor Used in Residual Risk Modeling: Acrylic and 
Modacrylic Fibers, Amino/Phenolic Resins, and Polycarbonate Production, 
available in the docket for this action (EPA-HQ-OAR-2012-0133).
---------------------------------------------------------------------------

    \14\ 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 these 
source categories, the data refinements employed consisted of using a 
peak-to-mean hourly emissions ratio based on source category-specific 
knowledge or data (rather than the default factor of 10) and using the 
site-specific facility layout to distinguish facility property from an 
area where the public could be exposed. These refinements are discussed 
more fully in the Draft Residual Risk Assessment for the Acrylic and 
Modacrylic Fibers Production Source Category, Draft Residual Risk 
Assessment for the Amino/Phenolic Resins Production Source Category, 
and Draft Residual Risk Assessment for the Polycarbonate Production 
Source Category, which are available in the docket for this action. 
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,\15\ 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 \16\ for 
HAP have been developed, we consider additional acute values (i.e., 
occupational and international values) to provide a more complete risk 
characterization. As a result, for most chemicals, the 15-minute 
occupational ceiling values are set at levels higher than a one-hour 
AEGL-1, making comparisons to them irrelevant unless the AEGL-1 or 
ERPG-1 levels are exceeded (U.S. EPA 2009). Such is not the case when 
comparing the available acute inhalation health effect reference values 
for formaldehyde (U.S. EPA 2009). See section V.B.2 of this preamble 
for additional information on the acute dose-response values for 
formaldehyde.
---------------------------------------------------------------------------

    \15\ 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.
    \16\ 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.
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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). We first determined whether any sources 
in the source categories 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 AMF and PC source categories, we did not identify emissions 
of any PB-HAP. Because we did not identify PB-HAP emissions, no further 
evaluation of multipathway risk was conducted for these source 
categories.
    For the APR source category, we identified emissions of lead 
compounds (1 facility), cadmium compounds (2 facilities) and POM 
(analyzed as benzo(a)pyrene toxic equivalency quotient (TEQ)) (2 
facilities). Because one or more of these PB-HAP are emitted by at 
least one facility in the APR source category, we proceeded to the 
second step of the evaluation. In this step, we determined whether the 
facility-specific emissions rates of each 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 each 
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. 
We conducted a sensitivity analysis on the screening scenario to ensure 
that its key design parameters would represent the upper end of the

[[Page 1689]]

range of possible values, such that it would represent a conservative 
but not impossible scenario. The facility-specific emissions rates of 
each of the PB-HAP were compared to the emission rate threshold values 
for each of the PB-HAP identified 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.
    For the purpose of developing emissions rates for our Tier I TRIM-
Screen, we derived emission levels for each PB-HAP (other than lead) at 
which the maximum excess lifetime cancer risk would be 1-in-1 million 
or, for HAP that cause non-cancer health effects, the maximum hazard 
quotient would be 1. If the emissions rate of any PB-HAP exceeds the 
Tier I screening emissions rate for any facility, we conduct a Tier II 
multipathway screen. In the Tier II screen, the location of each 
facility that exceeds 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 
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.
    In evaluating the potential multi-pathway risk from emissions of 
lead compounds, rather than developing a screening emissions rate for 
them, we compared maximum estimated chronic inhalation exposures with 
the level of the current National Ambient Air Quality Standard (NAAQS) 
for lead. Values below the level of the primary (health-based) lead 
NAAQS were considered to have a low potential for multi-pathway risk.
    For further information on the multipathway analysis approach, see 
the Draft Residual Risk Assessment for the Acrylic and Modacrylic 
Fibers Production Source Category, Draft Residual Risk Assessment for 
the Amino/Phenolic Resins Production Source Category, and Draft 
Residual Risk Assessment for the Polycarbonate Production Source 
Category, which are 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 emissions reductions that would be achieved by the 
control options under consideration. In these cases, the expected 
emissions reductions were applied to the specific HAP and emissions 
points in the source category 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. 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 (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, 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, we compare the 
HEM modeled inhalation exposures from the source category emissions of 
lead with the level of the secondary National Ambient Air Quality 
Standard (NAAQS) for lead.\17\ We consider values below the level of 
the secondary lead NAAQS to be unlikely to cause adverse environmental 
effects.
---------------------------------------------------------------------------

    \17\ 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.''
---------------------------------------------------------------------------

    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 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 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

[[Page 1690]]

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 except for lead, 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, 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-
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., 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 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 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, 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, EPA first determined 
whether any facilities in the AMF, APR and PC source categories emitted 
any of the seven environmental HAP. For the AMF and PC source 
categories, we did not identify emissions of any of the seven 
environmental HAP included in the screen. Because we did not identify 
environmental HAP emissions, no further evaluation of environmental 
risk was conducted for those source categories. For the APR source 
category, we identified emissions of lead compounds (1 facility), 
cadmium compounds (2 facilities) and POM (analyzed as benzo(a)pyrene 
TEQ) (2 facilities).
    Because one or more of the seven environmental HAP evaluated are 
emitted by at least one facility in the APR 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, and lead is 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

[[Page 1691]]

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 are in the 
ecological risk screening methodology for PB-HAPs.
    For purposes of ecological risk screening, 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 Acrylic and 
Modacrylic Fibers Production Source Category, Draft Residual Risk 
Assessment for the Amino/Phenolic Resins Production Source Category, 
and Draft Residual Risk Assessment for the Polycarbonate Production 
Source Category, which are 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 emissions sources at the facility for which we have 
data. The emissions data for generating these ``facility-wide'' risks 
were obtained from the 2005 NEI for the APR and PC source categories, 
and from the 2008 NEI for the AMF source category. 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 each of the three 
source categories addressed in this proposal. The Draft Residual Risk 
Assessment for the Acrylic and Modacrylic Fibers Production Source 
Category, Draft Residual Risk Assessment for the Amino/Phenolic Resins 
Production Source Category, and Draft Residual Risk Assessment for the 
Polycarbonate Production Source Category, available through the docket 
for this action, provide 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 emissions datasets, 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 Acrylic and 
Modacrylic Fibers Production Source Category, Draft Residual Risk 
Assessment for the Amino/Phenolic Resins Production Source Category, 
and Draft Residual Risk Assessment for the Polycarbonate Production 
Source Category, which are available in the docket for this action 
(EPA-HQ-OAR-2012-0133).
a. Uncertainties in the Emissions Datasets
    Although the development of the RTR datasets 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 emissions 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 emissions rates for the 
acute effects screening assessment were based on an emission adjustment 
factor applied to the average annual hourly emissions 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 estimate 
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

[[Page 1692]]

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.\18\ 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).
---------------------------------------------------------------------------

    \18\ Short-term mobility is movement from one microenvironment 
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 receptors where the block 
population is not well represented by a single location.
    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 receptors where the block 
population is not well represented by a single location.
    The assessment evaluates the cancer inhalation risks associated 
with pollutant exposures over a 70-year period, which is the assumed 
lifetime of an individual. In reality, both the length of time that 
modeled emissions 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 overstatement of 25 to 30 percent of exposures.\19\
---------------------------------------------------------------------------

    \19\ 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 during the time of worst-case impact.
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 Acrylic and Modacrylic 
Fibers Production Source Category, Draft Residual Risk Assessment for 
the Amino/Phenolic Resins Production Source Category, and Draft 
Residual Risk Assessment for the Polycarbonate Production Source 
Category, which are 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

[[Page 1693]]

represent a ``plausible upper limit to the true value of a quantity'' 
(although this is usually not a true statistical confidence limit).\20\ 
In some circumstances, the true risk could be as low as zero; however, 
in other circumstances the risk could be greater.\21\ 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).
---------------------------------------------------------------------------

    \20\ IRIS glossary (http://www.epa.gov/NCEA/iris/help_gloss.htm).
    \21\ 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,\22\ 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.
---------------------------------------------------------------------------

    \22\ 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 the 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 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 these source 
categories 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 unspeciated (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 Screening 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

[[Page 1694]]

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.\23\
---------------------------------------------------------------------------

    \23\ 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 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.\24\
---------------------------------------------------------------------------

    \24\ 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, which was 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

[[Page 1695]]

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). 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, which was 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, 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 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 
Acrylic and Modacrylic Fibers Production Source Category, Draft 
Residual Risk Assessment for the Amino/Phenolic Resins Production 
Source Category, and Draft Residual Risk Assessment for the 
Polycarbonate Production 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 level on maximum individual lifetime [cancer] risk (MIR) 
\25\ of approximately [1-in-10 thousand] [i.e., 100-in-1 million].'' 54 
FR 38045. 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.
---------------------------------------------------------------------------

    \25\ 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 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 Federal Register proposed rule.
    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. 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:

[[Page 1696]]

    ``[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'.''

54 FR 38057. 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 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.'' \26\
---------------------------------------------------------------------------

    \26\ 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 to this rulemaking 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 today's 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 
overlapping sources in the same category; and (3) for some persistent 
and bioaccumulative 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 emissions sources other than those that we have studied in 
depth during this RTR review, 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 emissions 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

[[Page 1697]]

reviewed were the NESHAP for various industries that were promulgated 
since the MACT standards being 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 
emissions sources in the AMF, APR and PC source categories, as well as 
the costs, non-air impacts and energy implications associated with the 
use of these technologies.
    We also consulted the EPA's RACT/BACT/LAER Clearinghouse (RBLC), 
which is a central database of air pollution control technology 
information that was established by the EPA to promote the sharing of 
information among permitting agencies and to aid in identifying future 
possible control technology options that might apply broadly to 
numerous sources within a category or apply only on a source-by-source 
basis.
    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 for the AMF Source 
Category

A. What actions are we taking pursuant to CAA sections 112(d)(2) and 
112(d)(3)?

    We identified the absence of an emissions limit for a potentially 
significant emission source within the provisions of the AMF MACT 
standards. Specifically, there are no emissions standards or other 
requirements for spinning lines that use a spin dope produced from a 
solution polymerization process at existing facilities.\27\ As this 
process is a significant source of emissions for the one facility in 
the source category, we are proposing to set standards for this process 
under CAA section 112(d)(2) and (3) in this action.
---------------------------------------------------------------------------

    \27\ Note that these uncontrolled emissions were included in the 
risk assessment for the AMF source category.
---------------------------------------------------------------------------

    Since there is only one facility in the source category, the 
current emissions level of the spinning line at this affected source at 
this facility represents the MACT floor. As part of our beyond-the-
floor analysis, we considered control options for the spinning line 
more stringent than the MACT floor. We identified two beyond-the-floor 
options: (1) A scrubber operating at 85 percent control efficiency; and 
(2) a regenerative thermal oxidizer operating at 95 percent control 
efficiency. Based on the emission stream flow rate and emissions 
information provided by the one facility in this source category, the 
capital costs of the scrubber option are estimated to be approximately 
$2.6 million, and the total annualized costs are estimated to be 
approximately $622,000. The capital costs of the thermal oxidizer 
option are estimated to be approximately $3.4 million and the total 
annualized costs are estimated to be approximately $1.5 million.
    The estimated HAP emissions reduction from the scrubber option is 
approximately 27 tpy. The cost effectiveness for the scrubber option is 
approximately $23,000/ton. The estimated HAP emissions reduction from 
the thermal oxidizer option is approximately 30 tpy. The cost 
effectiveness for the thermal oxidizer option is approximately $50,000/
ton. The incremental cost effectiveness between the 85 percent control 
option and the 95 percent control option is approximately $280,000/ton 
of HAP emission reduction. Table 3 summarizes the cost and emission 
reduction impacts of the proposed options.
    For further details on the assumptions and methodologies used in 
this analysis, see the technical memorandum titled MACT Floor and 
Beyond-the-Floor Analyses for Unregulated Emission Sources in the 
Acrylic and Modacrylic Fibers and Amino and Phenolic Resins Production 
Source Categories, available in the docket for this action.
    As discussed in section IV.C below, neither of these options are 
needed in order to support the EPA's finding under CAA section 112(f) 
that the AMF MACT standards already protect public health with an ample 
margin of safety. While we do not factor quantified risk reductions 
into CAA section 112(d)(2) beyond-the-floor analyses, for informational 
purposes we note that the scrubber option would reduce the MIR for the 
source category from 20 to 3 and reduce the maximum chronic non-cancer 
TOSHI from 0.1 to 0.02. The thermal oxidizer option would reduce the 
MIR for the source category from 20 to 1 and reduce the maximum chronic 
non-cancer TOSHI from 0.1 to 0.01.

                                           Table 3--AMF Solution Polymerization Spinning Line Options Impacts
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Incremental
                                                                                                                              Cost             cost
                      Regulatory alternatives                         HAP emissions   Capital cost ($   Annual cost ($   effectiveness    effectiveness
                                                                     reduction (tpy)      million)       million/yr)       ($/ton HAP      ($/ton  HAP
                                                                                                                            removed)         removed)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1 Baseline (MACT floor)............................................                0                0                0  ...............  ...............
2 Scrubber (Beyond-the-floor)......................................               27              2.6              0.6           23,000           23,000
3 Thermal Oxidizer (Beyond-the-floor)..............................               30              3.4              1.5           50,000          280,000
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We believe that the costs of these beyond-the-floor options are not 
reasonable, given the level of HAP emission reduction they would 
achieve. Therefore, we are proposing an emission standard that reflects 
the MACT floor. We determined the MACT floor using the emissions and 
production data provided by the facility and calculated production-
based emission rates for several years of production. Taking into 
account expected variability in the production-based emission rates, we 
calculated the MACT floor emission rate to be 20 kg organic HAP/Mg (40 
lb organic HAP/ton) of acrylic and modacrylic fiber produced.

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

1. Inhalation Risk Assessment Results
    Table 4 provides an overall summary of the inhalation risk 
assessment results for the AMF source category.

[[Page 1698]]

                                                     Table 4--AMF Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                              Maximum individual cancer risk                                    Maximum chronic non-cancer
                                     (in 1 million) \2\                        Annual cancer             TOSHI \3\
                             --------------------------------  Population at     incidence   -------------------------------- Maximum off-site acute non-
  Number of  facilities \1\       Actual         Allowable    risk >= 1-in-1    (cases per        Actual         Allowable           cancer HQ \4\
                                 emissions       emissions        million          year)         emissions       emissions
                                   level           level                                           level           level
--------------------------------------------------------------------------------------------------------------------------------------------------------
1...........................             20              20          81,000           0.006             0.1             0.1   HQAEGL-1 = 0.08
                                                                                                                               acrylonitrile.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk.
\3\ Maximum TOSHI. The target organ with the highest TOSHI for the AMF source category is the respiratory system.
\4\ The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop an array of HQ values. HQ values
  shown use the lowest available acute threshold value, which in most cases is the REL. When HQ values exceed 1, we also show HQ values using the next
  lowest available acute dose-response value. See section III.A.3 of this preamble for explanation of acute dose-response values.

    The inhalation risk modeling was performed using actual emissions 
level data. As shown in Table 4, the results of the inhalation risk 
assessment indicated the maximum lifetime individual cancer risk could 
be up to 20-in-1 million, the estimated maximum chronic non-cancer 
TOSHI value is 0.1 and the estimated maximum off-facility site acute HQ 
value is 0.08, based on the actual emissions level and the AEGL-1 value 
for acrylonitrile. The total estimated national cancer incidence from 
this facility based on actual emission levels is 0.006 excess cancer 
cases per year or one case in every 170 years.
    Based on our analysis, we estimate that actual emissions 
approximate emissions allowable under the MACT standards, as we are not 
aware of any situations in which the facility is conducting additional 
work practices or operating a control device such that it achieves a 
greater emission reduction than required. Therefore, the risk results 
for MACT-allowable emissions are approximately equal to those for 
actual emissions. For more detail about this estimate of the ratio of 
actual to MACT-allowable emissions and the estimation of MACT-allowable 
emission levels (and associated risks and impacts), see the memorandum, 
MACT Allowable Emissions and Risks for the Acrylic and Modacrylic 
Fibers, Amino/Phenolic Resins, and Polycarbonate Production Source 
Categories, available in the docket for this action (EPA-HQ-OAR-2012-
0133).
2. Acute Risk Results
    We estimate that the maximum off-facility site acute HQ value is 
0.08, based on the actual emissions level and the AEGL-1 value for 
acrylonitrile.
3. Multipathway Risk Screening Results
    There were no reported emissions of PB-HAP, indicating low 
potential for human health multipathway risks as a result of PB-HAP 
emissions from this source category.
4. Environmental Risk Screening Results
    The emissions data for the AMF source category indicate that 
sources within this source category do not emit any of the seven 
pollutants that we identified as ``environmental HAP,'' as discussed 
earlier in this preamble. Based on the processes and materials used in 
the source category, we do not expect any of the seven environmental 
HAP to be emitted. Also, we are unaware of any adverse environmental 
effect caused by emissions of HAP that are emitted by this source 
category. Therefore, we do not expect an adverse environmental effect 
as a result of HAP emissions from this source category.
5. Facility-Wide Risk Results
    Table 5 presents the results of the facility-wide risk assessment 
for the AMF source category. This assessment was conducted based on 
actual emission levels. For detailed facility-specific results, see 
Appendix 4 of the Draft Residual Risk Assessment for the Acrylic and 
Modacrylic Fibers Production Source Category in the docket for this 
action.

           Table 5--AMF Facility-Wide Risk Assessment Results
------------------------------------------------------------------------
 
------------------------------------------------------------------------
Number of facilities analyzed..............................            1
------------------------------------------------------------------------
                               Cancer Risk
------------------------------------------------------------------------
Estimated maximum facility-wide individual cancer risk (in            20
 1 million)................................................
Number of facilities with estimated facility-wide                      0
 individual cancer risk of 100-in-1 million or more........
Number of facilities at which the AMF source category                  0
 contributes 50 percent or more to the facility-wide
 individual cancer risks of 100-in-1 million or more.......
Number of facilities at which the AMF source category                  1
 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.............          0.1
Number of facilities with facility-wide maximum non-cancer             0
 TOSHI greater than 1......................................
Number of facilities at which the AMF source category                  0
 contributes 50 percent or more to the facility-wide
 maximum non-cancer TOSHI of 1 or more.....................
------------------------------------------------------------------------

    The facility-wide MIR from all HAP emissions at the single AMF 
facility is estimated to be 20-in-1 million, based on actual emissions. 
The facility-wide maximum individual chronic non-cancer TOSHI is 
estimated to be 0.1 based on actual emissions.

[[Page 1699]]

6. What demographic groups might benefit from this regulation?
    To examine the potential for any environmental justice (EJ) issues 
that might be associated with the source category, we performed a 
demographic analysis of the population close to the facility. In this 
analysis, we evaluated the distribution of HAP-related cancer and non-
cancer risks from the AMF source category across different social, 
demographic and economic groups within the populations living near 
facilities identified as having the highest risks. The methodology and 
the results of the demographic analyses are included in a technical 
report, Environmental Justice Review: Amino/Phenolic Resins, Acrylic 
and Modacrylic Fibers Production, and Polycarbonate Production, 
available in the docket for this action.
    The results of the demographic analysis are summarized in Table 6 
below. These results, for various demographic groups, are based on the 
estimated risks from actual emissions levels for the population living 
within 50 km of the facilities.

                                 Table 6--AMF Demographic Risk Analysis Results
----------------------------------------------------------------------------------------------------------------
                                                                                    Population
                                                                                    with Cancer     Population
                                                                    Nationwide      risk at or     with chronic
                                                                                   above 1-in-1    hazard index
                                                                                      million         above 1
----------------------------------------------------------------------------------------------------------------
Total Population................................................     312,861,256          81,000               0
----------------------------------------------------------------------------------------------------------------
                                                 Race by Percent
----------------------------------------------------------------------------------------------------------------
White...........................................................              72              63               0
All Other Races.................................................              28              37               0
----------------------------------------------------------------------------------------------------------------
                                                 Race by Percent
----------------------------------------------------------------------------------------------------------------
White...........................................................              72              63               0
African American................................................              13              30               0
Native American.................................................               1             0.4               0
Other and Multiracial...........................................              14               7               0
----------------------------------------------------------------------------------------------------------------
                                              Ethnicity by Percent
----------------------------------------------------------------------------------------------------------------
Hispanic........................................................              17               6               0
Non-Hispanic....................................................              83              94               0
----------------------------------------------------------------------------------------------------------------
                                                Income by Percent
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................................              14              14               0
Above Poverty Level.............................................              86              86               0
----------------------------------------------------------------------------------------------------------------
                                              Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 and without High School Diploma.........................              10              17               0
Over 25 and with a High School Diploma..........................              90              83               0
----------------------------------------------------------------------------------------------------------------

    The results of the AMF source category demographic analysis 
indicate that emissions from the source category expose approximately 
81,000 people to a cancer risk at or above 1-in-1 million and 
approximately 0 people to a chronic non-cancer TOSHI greater than 1. 
The demographic results for the population potentially impacted by AMF 
emissions indicate that the minority and African American percentages 
are higher than the national percentages for these categories (37 
percent minority compared to 28 percent nationwide, and 30 percent 
African American compared to 13 percent nationwide). Furthermore, the 
demographic results for the population potentially impacted by these 
source category emissions indicate that the percentage of people over 
25 and without a high school diploma is also slightly higher than the 
nationwide percentage (17 percent compared to 15 percent nationwide). 
The other demographic percentages for the people exposed to a risk 
greater than or equal to 1-in-1 million as a result of AMF emissions 
are essentially the same or lower than the respective nationwide 
percentages.
    Implementation of the provisions included in this proposal are not 
expected to reduce the number of people estimated to have a cancer risk 
greater than 1-in-1 million due to HAP emissions from these sources 
(81,000 people). This is because the proposed emission rate for 
spinning lines that use spin dope produced from a solution 
polymerization process is equal to the MACT floor for the one facility 
in the AMF source category, which will not result in any quantifiable 
emission reductions.

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

1. Risk Acceptability
    As noted in section III.B of this preamble, we weigh all health 
risk factors in our risk acceptability determination, including the 
MIR; the number of persons in various risk ranges; cancer incidence; 
the maximum non-cancer HI; the maximum acute non-cancer HQ; the extent 
of non-cancer risks; the potential for adverse environmental effects; 
distribution of risks in the exposed population; and risk estimation 
uncertainty (54 FR 38044, September 14, 1989). For the AMF source 
category, the risk analysis we performed indicates that the cancer 
risks to the individual most exposed could be up to 20-in-1 million due 
to

[[Page 1700]]

both actual and allowable emissions. This value is considerably less 
than 100-in-1 million, which is the presumptive level of acceptability. 
The risk analysis also shows low cancer incidence (1 in every 170 
years), low potential for human health multipathway effects because no 
PB-HAP are emitted from this source category, and that chronic non-
cancer health impacts are unlikely.
    We estimate that the worst-case acute HQ value is 0.08 for 
acrylonitrile, based on an AEGL-1. As described earlier in this 
preamble, the acute assessment includes some conservative assumptions 
and some uncertainties. Considering the improbable assumption that 
worst-case meteorological conditions are present at the same time that 
maximum hourly emissions of acrylonitrile exceed the average hourly 
emission rate by a factor of 10 at most emission points simultaneously, 
coincident with individuals being in the location of maximum impact, 
and considering the low acute HQ values based on the AEGL-1 dose-
response value, we believe that it is unlikely that HAP emissions from 
this source category would result in adverse acute health effects. 
Further discussion on these assumptions can be found in the Draft 
Residual Risk Assessment for the Acrylic and Modacrylic Fibers 
Production Source Category, which is available in the docket for this 
action.
    Our additional analysis of facility-wide risks showed that the 
maximum facility-wide cancer risk is 20-in-1 million and that the 
maximum chronic non-cancer TOSHI is estimated to be 0.1.
    The EPA has weighed the various health risk measures and health 
factors, including risk estimation uncertainty, discussed above and in 
section III.A.8 of this preamble, and we are proposing that the risks 
from the AMF source category are acceptable.
2. Ample Margin of Safety Analysis
    Although we are proposing to determine that the risks from the AMF 
source category are acceptable, risk estimates for 81,000 individuals 
in the exposed population are above 1-in-1 million. Consequently, we 
considered whether the AMF MACT standards provide an ample margin of 
safety to protect public health. In this analysis, we investigated 
available emissions control options that might reduce the risk 
associated with emissions from the source category and considered this 
information along with all of the health risks and other health 
information considered in the risk acceptability determination.
    For the AMF source category, we did not identify any further 
control options for storage vessels, process vents, spinning lines or 
wastewater beyond what is currently required in the rule or is being 
proposed in this action (see section IV.A of this preamble for our 
proposed actions related to spinning lines that use a spin dope 
produced from a polymerization process). For equipment leaks, as 
discussed in section IV.D of this preamble, we identified an emission 
control option of requiring compliance with subpart UU rather than 
subpart TT, and either including or not including the connector LDAR 
requirements of subpart UU. We estimate that less than 1 percent of the 
emissions and associated risk at the MACT-allowable levels could be 
attributed to equipment leaks. We estimate the HAP reduction resulting 
from compliance with subpart UU without the subpart UU connector 
monitoring requirements would be 0.2 tpy from the baseline MACT-
allowable emissions level, with a cost effectiveness of $1,500/ton HAP 
reduction. We estimate the HAP reduction resulting from compliance with 
subpart UU including the subpart UU connector monitoring requirements 
would be 0.5 tpy from the baseline MACT-allowable emissions level, with 
a cost effectiveness of $14,000/ton HAP reduction. Neither of these 
additional control options for equipment leaks would achieve a 
reduction in the maximum individual cancer risks or any of the other 
health risk metrics. Due to the minimal reductions in HAP emissions and 
risk, along with the costs associated with these options, we are 
proposing that additional HAP emissions controls for AMF production 
equipment leaks are not necessary to provide an ample margin of safety 
to protect public health.
    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 additional factors 
relating to the appropriate level of control, including the costs and 
economic impacts of emissions controls, technological feasibility, 
uncertainties and other relevant factors in making our ample margin of 
safety determination. Considering all of these factors, the EPA is 
proposing to determine that the current MACT standards in 40 CFR part 
63, subpart YY for the AMF source category provide an ample margin of 
safety to protect public health.
3. Adverse Environmental Effects
    We did not identify emissions of the seven environmental HAP 
included in our environmental risk screening, and are unaware of any 
adverse environmental effects caused by other HAP emitted by this 
source category. Therefore, we do not expect there to be an adverse 
environmental effect as a result of HAP emissions from this source 
category. Accordingly, we are proposing to determine that it is not 
necessary to set a more stringent standard to prevent, taking into 
consideration costs, energy, safety, and other relevant factors, an 
adverse environmental effect.

D. What are the results and proposed decisions based on our technology 
review?

    In the period of time since the AMF MACT standards were 
promulgated, the EPA has developed air toxics regulations for numerous 
source categories that emit organic HAP from the same type of emissions 
sources that are present in the AMF source category. We reviewed the 
regulatory requirements and technical analyses for these regulations 
for new practices, processes and control techniques. We also conducted 
a search of the BACT/RACT/LAER clearinghouse for controls for VOC- and 
HAP-emitting processes in the Polymers and Resins and the Synthetic 
Organic Chemical Manufacturing Industry (SOCMI) categories with permits 
dating back to 1997.
    The AMF MACT standards currently require compliance with either 
subpart TT or subpart UU of 40 CFR part 63 to control emissions from 
equipment leaks. While many provisions of these two rules are the same 
or similar, subpart UU requires the use of a lower leak definition for 
valves in gas and vapor service and in light liquid service, pumps in 
light liquid service, and connectors in gas and vapor service and in 
light liquid service. Specifically, subpart UU lowers the leak 
definition for valves from 10,000 ppm (in subpart TT) to 500 ppm, 
lowers the leak definition for pump seals from 10,000 ppm (in subpart 
TT) to 1,000 ppm, and requires instrument monitoring of connectors with 
a leak definition of 500 ppm, as opposed to sensory monitoring (in 
subpart TT). We identified the more stringent leak definitions of 
subpart UU as a development in practices, processes or control 
technologies for LDAR programs. We also note that the one facility in 
this source category is complying with subpart TT.

[[Page 1701]]

    Since the one facility in this source category is currently 
complying with subpart TT, we analyzed the costs and emission 
reductions associated with switching from a subpart TT LDAR program to 
a subpart UU LDAR program, both including and not including the subpart 
UU connector monitoring requirements, which can be an expensive 
component of an LDAR program. The estimated costs and emissions 
reductions associated with these options are shown in Table 7. For 
Option 1 (subpart UU without connector monitoring), we estimated the 
capital costs to be approximately $1,400, and the total annualized 
costs are estimated to be approximately $220. The estimated HAP 
emissions reduction is approximately 0.2 tpy, and the cost 
effectiveness is approximately $1,500/ton. For Option 2 (subpart UU 
with connector monitoring), we estimated the capital costs to be 
approximately $19,000, and the total annualized costs are estimated to 
be approximately $7,600. The estimated HAP emissions reduction is 
approximately 0.5 tpy, and the cost effectiveness is approximately 
$14,000/ton. The incremental cost effectiveness between Option 1 and 
Option 2 is approximately $19,000.
    While, as discussed in section IV.C above, the equipment leaks 
control options are not needed to support the EPA's finding under CAA 
section 112(f) that the AMF MACT standards already protect public 
health with an ample margin of safety, and while we do not factor 
quantified risk reductions into CAA section 112(d)(6) technology review 
analyses, for informational purposes we note that neither Option 1 nor 
Option 2 of the technology review for equipment leaks would reduce the 
MIR or the maximum chronic non-cancer TOSHI for the source category.

                                   Table 7--AMF Equipment Leak Options Impacts
----------------------------------------------------------------------------------------------------------------
                                                                                                    Incremental
                                  HAP  emissions                                       Cost            cost
     Regulatory alternatives         reduction     Capital cost   Annual cost ($/  effectiveness   effectiveness
                                       (tpy)            ($)             yr)         ($/ton HAP      ($/ton HAP
                                                                                     removed)        removed)
----------------------------------------------------------------------------------------------------------------
Option 1: Subpart UU, no                     0.2           1,400             220           1,500
 connector monitoring...........
Option 2: Subpart UU with                    0.5          19,000           7,600          14,000          19,000
 connector monitoring...........
----------------------------------------------------------------------------------------------------------------

    Based on this analysis, we believe the costs of Option 1 are 
reasonable, given the level of HAP emissions reduction that would be 
achieved with this control option. We believe the costs of Option 2 are 
not reasonable, given the level of HAP emission reduction that control 
option would achieve. Therefore, we are proposing to revise the AMF 
MACT standards to require facilities to comply with subpart UU rather 
than subpart TT, with the exception of connectors in gas and vapor 
service and in light liquid service. We are proposing to retain the 
option to comply with either subpart TT or subpart UU for these 
components.
    For storage vessels, process vents, spinning line fugitive 
emissions and wastewater, beyond what is currently required in the rule 
or is being proposed in this action, we did not identify: any add-on 
control technology or other equipment that was not identified and 
considered during MACT development; any improvements in add-on control 
technology or other equipment (that was identified and considered 
during MACT development) that could result in significant additional 
HAP emission reduction; any work practice or operational procedure that 
was not identified and considered during MACT development; any process 
change or pollution prevention alternative that could be broadly 
applied that was not identified and considered during MACT development; 
or any significant changes in the cost (including cost effectiveness) 
of applying controls (including controls the EPA considered during MACT 
development).
    For more detailed information on the results of the EPA's 
technology review, see the memorandum, Developments in Practices, 
Processes, and Control Technologies for the Acrylic and Modacrylic 
Fibers Source Category, available in the docket for this action (EPA-
HQ-OAR-2012-0133).

V. Analytical Results and Proposed Decisions for the APR Source 
Category

A. What actions are we taking pursuant to CAA sections 112(d)(2) and 
112(d)(3)?

    We identified the absence of a limit for two potentially 
significant emission sources within the provisions of the APR MACT 
standards. These two emissions sources are storage vessels and 
continuous process vents at existing facilities.
1. Storage Vessels
    Currently, storage vessels at existing facilities in the APR source 
category are unregulated by the APR MACT standards. Under CAA section 
112(d)(2) and (3), we are proposing that the MACT floor level of 
control is to either maintain and operate a storage vessel with an 
internal or an external floating roof, or use a fixed roof tank with 
emissions vented through a closed vent system to any combination of 
control devices that achieve a 95-percent emissions reduction or reduce 
emissions to specified control device outlet concentrations. These 
requirements would apply to storage vessels having a capacity of 50,000 
gallons or greater and a vapor pressure of 2.45 psia or greater, or a 
capacity of 90,000 gallons or greater and a vapor pressure of 0.15 psia 
or greater. We determined that this level of control represents the 
MACT floor using available data from the original development of the 
APR MACT standards, as well as from title V permits for facilities in 
the source category.
    As part of our beyond-the-floor analysis, we considered control 
options more stringent than the MACT floor. We identified two beyond-
the-floor options. For Option 1, we evaluated revising the 
applicability of the MACT floor to include smaller capacity storage 
vessels and/or storage vessels containing liquids with lower vapor 
pressures, such that these additional storage vessels would be subject 
to the MACT floor control requirements for storage vessels. We 
evaluated the impacts of changing these thresholds to be consistent 
with other storage vessel standards already required for the chemical 
industry regulated by the HON. Specifically, as shown in Table 8, under 
this option, we evaluated requiring the MACT floor level of emissions 
control for storage vessels of capacities greater than or equal to 
20,000 gal, but less than 40,000 gal if the MTVP is 1.9 psia or 
greater, and for storage vessels of capacities greater than or equal to 
40,000 gal, but less than 90,000 gal if the MTVP is 0.75 psia or

[[Page 1702]]

greater. Control would also be required for storage vessels of 90,000 
gal or greater, if the MTVP is 0.15 psia or greater, as required under 
the MACT floor, but which is not a requirement of the HON. Since 
available data for this source category indicates most APR storage 
vessels have fixed-roofs, under Option 2, we considered the impacts of 
requiring a 98-percent emissions reduction for storage vessels meeting 
the capacity and vapor pressure thresholds under Option 1, assuming 
emissions would be vented through a closed vent system to a 
regenerative thermal oxidizer (RTO) to attain this increased level of 
control.
    Table 9 presents the impacts for the MACT floor and the two beyond-
the-floor options considered. Our analysis indicates that all existing 
storage vessels exceeding the MACT floor capacity and vapor pressure 
thresholds are already controlled at the 95-percent level; therefore, 
we expect no costs of additional emissions reductions associated with 
the MACT floor level of control. Available data also indicates that 
there may be no existing storage vessels meeting the size and vapor 
pressure thresholds of Option 1 that are not already controlled at the 
95-percent level. In this case, we would expect no costs or additional 
emissions reductions associated with Option 1. However, in order to 
show the maximum potential impacts from this option, we used an 
analysis of an APR model plant, which assumes that one tank is already 
meeting the control requirements of the MACT floor and that one 
additional tank would require control under Option 1. In this analysis, 
we assumed that the additional tank would be controlled with the same 
control device as the controlled tank but would require ductwork to 
route emissions there. Since our data indicates that six facilities 
report emissions from storage vessels, we assumed that just these six 
facilities would be impacted by Option 1. As seen in Table 9 of this 
preamble, for Option 1, we estimated the nationwide capital costs to be 
approximately $67,000, and the total nationwide annualized costs are 
estimated to be approximately $15,000. The estimated HAP emissions 
reduction is approximately 6.3 tpy. For Option 2, we estimated the 
nationwide capital costs to be approximately $5.2 million and the 
nationwide total annualized costs are estimated to be approximately 
$1.6 million. The estimated nationwide HAP emissions reduction is 
approximately 7.0 tpy, and the incremental cost effectiveness between 
Option 1 and Option 2 is approximately $2.3 million/ton. We solicit 
comment on the sizes of storage vessels and the vapor pressures of the 
contents of these storage vessels at APR facilities.
    For further details on the assumptions and methodologies used in 
this analysis, see the technical memorandum titled MACT Floor and 
Beyond-the-Floor Analyses for Unregulated Emission Sources in the 
Acrylic and Modacrylic Fibers and Amino and Phenolic Resins Production 
Source Categories, available in the docket for this action.
    While, as discussed in section V.B below, the storage vessel 
control options are not needed to support the EPA's finding under CAA 
section 112(f) that the APR MACT standards already protect public 
health with an ample margin of safety, and while we do not factor 
quantified risk reductions into CAA section 112(d)(2) beyond-the-floor 
analyses, for informational purposes we note that neither Option 1 nor 
Option 2 for storage vessels would reduce the MIR for the source 
category because the MIR is not caused by emissions from storage 
vessels. However, the maximum non-cancer TOSHI is due to emissions from 
storage vessels. Assuming the storage vessel emissions contributing to 
this TOSHI are from an uncontrolled storage vessel, under both Options 
1 and 2, the TOSHI would be reduced to less than the risk caused by 
other emission point types. The maximum TOSHI at the MACT-allowable 
level would be reduced from 0.7 to 0.07 with either storage vessel 
control option.

   Table 8--Storage Tank Size and Vapor Pressure Thresholds Considered
           Under the MACT Floor and Beyond-the-Floor Analyses
------------------------------------------------------------------------
                                  Size and vapor pressure thresholds for
                                                  control
     Regulatory alternatives     ---------------------------------------
                                                         Vapor pressure
                                    Size  (gallons)          (psia)
------------------------------------------------------------------------
MACT Floor......................  50,000 =2.45
                                  90,000 =0.15
Options 1 and 2.................  20,000 =1.9
                                   =0.75
                                   =0.15
------------------------------------------------------------------------

               Table 9--Nationwide Emissions Reduction and Cost Impacts of Control Options for Storage Vessels at Existing APR Facilities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                            Cost        Incremental cost
                                                                      HAP emissions    Capital cost     Annual cost     effectiveness     effectiveness
                      Regulatory alternatives                           reduction           ($)           ($/yr)         ($/ton HAP        ($/ton HAP
                                                                          (tpy)                                           removed)          removed)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline (MACT floor)..............................................              0                 0               0  ................  ................
Option 1 (Beyond-the-floor)\1\.....................................              6.3          67,000          15,000             2,400             2,400
Option 2 (Beyond-the-floor)........................................              7.0       5,200,000       1,600,000           230,000         2,200,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The potential costs and emissions reductions of Option 1 regulatory alternatives are presented here based on a model facility with a single
  additional storage tank above the thresholds at which control would be required. However, available data indicate that there may be no existing
  facilities with uncontrolled tanks above the thresholds at which control would be required. In this case, there would be no costs or emissions
  reductions associated with these regulatory alternatives.

    Based on this analysis, we believe that the costs of Option 1 are 
reasonable, given the level of HAP emissions reduction this option 
would achieve. We believe that the costs of Option 2 are not 
reasonable, given the level of HAP

[[Page 1703]]

emissions reduction this option would achieve. Therefore, we are 
proposing to revise the APR MACT standards to require the MACT floor 
level of control for storage vessels at existing affected sources with 
the specified capacities and vapor pressures for Option 1.
2. Continuous Process Vents
    The EPA has identified the presence of uncontrolled continuous 
process vents at the two facilities in the APR source category (Georgia 
Pacific in Crossett, AR, and BTL Specialty Resins in Toledo, OH). Under 
CAA section 112(d)(2) and (3), we are proposing that the MACT floor 
level of control is to reduce organic HAP either by 85 percent or to a 
concentration of 20 parts per million by volume (ppmv), when using a 
combustion control device, or to a concentration of 50 ppmv when using 
a non-combustion control device. We determined that this level of 
control represents the MACT floor using available data from the 
original development of the APR MACT standards, as well as from title V 
permits for facilities in the source category.
    As part of our beyond-the-floor analysis, we considered control 
options more stringent than the MACT floor and identified two such 
options. For Option 1, we evaluated the impacts of requiring a 95-
percent emissions reduction, assuming that a scrubber would be used to 
achieve this increased level of control. For Option 2 we evaluated the 
impacts of requiring a 98-percent emissions reduction, assuming either 
a recuperative thermal oxidizer or a regenerative thermal oxidizer 
would be used to achieve this increased control level.
    Table 10 presents the impacts for the MACT floor and the two 
beyond-the-floor options considered. As seen in Table 10, the MACT 
floor level of control is expected to reduce HAP emissions by 
approximately 20.1 tpy and have a cost effectiveness of $16,900/ton of 
HAP removed. For Option 1, we estimated the capital costs to be 
approximately $1.3 million, and the total annualized costs are 
estimated to be approximately $390,000. The estimated HAP emissions 
reduction is approximately 22.5 tpy, and the incremental cost 
effectiveness between the MACT floor and Option 1 is approximately 
$19,500/ton. For Option 2, we estimated the capital costs to be 
approximately $3.7 million, and the total annualized costs are 
estimated to be approximately $1.2 million. The estimated HAP emissions 
reduction is approximately 23.2 tpy, and the incremental cost 
effectiveness between Option 1 and Option 2 is approximately $1.1 
million/ton. We solicit comment on the emissions and emissions release 
parameters from continuous process vents at existing APR facilities.
    For further details on the assumptions and methodologies used in 
this analysis, see the technical memorandum titled MACT Floor and 
Beyond-the-Floor Analyses for Unregulated Emission Sources in the 
Acrylic and Modacrylic Fibers and Amino and Phenolic Resins Production 
Source Categories, available in the docket for this action.
    While, as discussed in section V.B below, the continuous process 
vent control options are not needed to support the EPA's finding under 
CAA section 112(f) that the APR MACT standards already protect public 
health with an ample margin of safety, and while we do not factor 
quantified risk reductions into CAA section 112(d)(2) beyond-the-floor 
analyses, for informational purposes we note that neither Option 1 nor 
Option 2 for continuous process vents would reduce the MIR or the 
maximum chronic non-cancer TOSHI for the source category because 
neither the MIR nor the non-cancer TOSHI is not caused by emissions 
from continuous process vents.

  Table 10--Nationwide Emissions Reduction and Cost Impacts of Control Options for Continuous Process Vents at
                                             Existing APR Facilities
----------------------------------------------------------------------------------------------------------------
                                                                                    Cost        Incremental cost
                              HAP  emissions   Capital cost   Annual cost ($/   effectiveness     effectiveness
   Regulatory alternatives       reduction      (million $)         yr)          ($/ton HAP        ($/ton HAP
                                   (tpy)                                          removed)          removed)
----------------------------------------------------------------------------------------------------------------
Baseline (MACT floor).......            20.1             1.1         340,000            16,900  ................
Option 1 (Beyond-the-floor).            22.5             1.3         390,000            17,200            19,500
Option 2 (Beyond-the-floor).            23.2             3.7       1,200,000            51,000         1,100,000
----------------------------------------------------------------------------------------------------------------

    Based on this analysis, we do not believe the costs of the either 
beyond-the-floor option are reasonable, given the level of HAP 
emissions reduction that would be achieved with these control options. 
Therefore, we are proposing to revise the APR MACT standards to require 
the MACT floor level of control for continuous process vents.

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

1. Inhalation Risk Assessment Results
    Table 11--provides an overall summary of the inhalation risk 
assessment results for the APR source category.

                                                    Table 11--APR Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                              Maximum individual cancer risk                                    Maximum chronic non-cancer
                                    (in 1 million) \2\                         Annual cancer             TOSHI \3\
                             --------------------------------  Population at     incidence   --------------------------------   Maximum off-site acute
  Number of  facilities \1\       Actual         Allowable    risk >= 1-in-1    (cases per        Actual         Allowable         non-cancer HQ \4\
                                 emissions       emissions        million          year)         emissions       emissions
                                   level           level                                           level           level
--------------------------------------------------------------------------------------------------------------------------------------------------------
18..........................              9              10           6,300           0.001             0.2             0.7   HQREL = 10 formaldehyde
                                                                                                                               HQAEGL-1 = 0.5
                                                                                                                               formaldehyde
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk.

[[Page 1704]]

 
\3\ Maximum TOSHI. The target organ with the highest TOSHI for the APR source category is the respiratory system.
\4\ The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop an array of HQ values. HQ values
  shown use the lowest available acute threshold value, which in most cases is the REL. When HQ values exceed 1, we also show HQ values using the next
  lowest available acute dose-response value. See section III.A.3 of this preamble for explanation of acute dose-response values.

    The inhalation risk modeling was performed using actual emissions 
level data. As shown in Table 11, the results of the inhalation risk 
assessment indicated the maximum lifetime individual cancer risk could 
be up to 9-in-1 million, the estimated maximum chronic non-cancer TOSHI 
value is 0.2 and the estimated maximum off-facility site acute HQ value 
is 10, based on the actual emissions level and the REL value for 
formaldehyde. The total estimated national cancer incidence from these 
facilities based on actual emission levels is 0.001 excess cancer cases 
per year or one case in every 1,000 years.
    Based on our analysis, we estimate that the MACT-allowable 
emissions levels of organic HAP could be up to 3.4 times the actual 
emissions for reactor batch process vents in this source category. 
Because it was not possible to determine whether an emission point was 
a reactor batch process vent or a non-reactor batch process vent in the 
NEI data available for this source category, we applied the 3.4 factor 
to all organic HAP emissions associated with point (rather than 
fugitive) sources to be conservative. The maximum lifetime individual 
cancer risk associated with emissions from point sources is estimated 
to be 3-in-1 million at actual emissions levels. Applying the 3.4 
factor to this value results in a MACT-allowable cancer risk of 10-in-1 
million. The maximum TOSHI associated with emissions from point sources 
is estimated to be 0.2 based on actual emissions levels, and 
application of the 3.4 factor results in a TOSHI at the MACT-allowable 
emissions level of approximately 0.7. For more detail about this 
estimate of the ratio of actual to MACT-allowable emissions and the 
estimation of MACT-allowable emission levels (and associated risks and 
impacts), see the memorandum, MACT Allowable Emissions and Risks for 
the Acrylic and Modacrylic Fibers, Amino/Phenolic Resins, and 
Polycarbonate Production Source Categories, available in the docket for 
this action (EPA-HQ-OAR-2012-0133).
2. Acute Risk Results
    We estimate that the maximum off-facility site acute HQ value is 
10, based on the actual emissions level and the REL value for 
formaldehyde. The worst-case maximum estimated 1-hour exposure to 
formaldehyde outside the facility fence line is 0.6 mg/m\3\. This 
estimated worst-case exposure exceeds the 1-hour REL by a factor of 10 
(HQREL = 10) and is below the 1-hour AEGL-1 
(HQAEGL-1 = 0.5). This exposure estimate does not exceed the 
AEGL-1, but does exceed the workplace ceiling level guideline for the 
formaldehyde value developed by the National Institutes for 
Occupational Safety and Health (NIOSH) \28\ ``for any 15 minute period 
in a work day'' (NIOSH REL-ceiling value of 0.12 mg/m\3\; 
HQNIOSH = 5). The estimate is also above the value developed 
by the American Conference of Governmental Industrial Hygienists 
(ACGIH) as ``not to be exceeded at any time'' (ACGIH TLV-ceiling value 
of 0.37 mg/m\3\; HQACGIH = 2). Additionally, the estimated 
maximum acute exposure exceeds the Air Quality Guideline value that was 
developed by the World Health Organization \29\ for 30-minute exposures 
(0.1 mg/m\3\; HQWHO = 6). We solicit comment on the use of 
the occupational values described above in the interpretation of these 
worst-case acute screening exposure estimates for the APR source 
category.
---------------------------------------------------------------------------

    \28\ NIOSH Occupational Safety and Health Guideline for 
Formaldehyde; http://www.cdc.gov/niosh/docs/81-123/pdfs/0293.pdf.
    \29\ WHO (2000). Chapter 5.8 Formaldehyde, in Air Quality 
Guidelines for Europe, second edition. World Health Organization 
Regional Publications, European Series, No. 91. Copenhagen, Denmark. 
Available on-line at http://www.euro.who.int/data/assets/pdf_file/0005/74732/E71922.pdf.
---------------------------------------------------------------------------

3. Multipathway Risk Screening Results
    Emissions of three PB-HAP are reported in the data set for this 
source category, including lead compounds (1 facility), cadmium 
compounds (2 facilities) and POM (analyzed as benzo(a)pyrene TEQ) (2 
facilities). Reported emissions of cadmium compounds and POM are lower 
than the multipathway screening levels for those PB-HAP, indicating low 
potential for multipathway risks. Lead is a PB-HAP, but the National 
Ambient Air Quality Standards (NAAQS) value (which was used for the 
chronic non-cancer risk assessment) takes into account air-related 
multipathway exposures, so a separate multipathway screening value was 
not developed. Results of the analysis for lead indicate that the 
maximum HEM modeled annual off-site ambient lead concentration was less 
than 1 percent of the NAAQS for lead, and if the annual emissions 
occurred during a 3-month period (which is highly unlikely) the maximum 
3-month rolling average concentrations would still be less than 1 
percent of the NAAQS, indicating low potential for multipathway risks 
from lead emissions from these facilities. Emissions of lead from this 
source category were limited to 0.03 lb/yr from a single facility.
4. Environmental Risk Screening Results
    As described in section III.A.6, we conducted an environmental risk 
screening assessment for the APR source category. In the Tier I 
screening analysis for the PB-HAP other than lead emitted by some 
sources in the category (POM and cadmium), none of the individual 
modeled concentrations for any facility in the source category exceeds 
any of the ecological benchmarks (either the LOAEL or NOAEL). 
Therefore, we did not conduct a Tier II assessment. For lead compounds, 
we did not estimate any exceedances of the secondary lead NAAQS. Acid 
gas emissions were not identified from any source in the category. 
Based on our screening analysis, we did not identify an adverse 
environmental effect as defined in CAA section 112(a)(7) from HAP 
emissions from this source category.
5. Facility-Wide Risk Results
    Table 12 displays the results of the facility-wide risk assessment 
for the APR source category. This assessment was conducted based on 
actual emission levels. For detailed facility-specific results, see 
Appendix 4 of the Draft Residual Risk Assessment for the Amino/Phenolic 
Resins Production Source Category in the docket for this action.

[[Page 1705]]

           Table 12--APR Facility-Wide Risk Assessment Results
------------------------------------------------------------------------
 
------------------------------------------------------------------------
Number of facilities analyzed..........................             18
Cancer Risk:
    Estimated maximum facility-wide individual cancer                9
     risk (in 1 million)...............................
    Number of facilities with estimated facility-wide                0
     individual cancer risk of 100-in-1 million or more
    Number of facilities at which the APR 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 at which the APR 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.....              0.2
    Number of facilities with facility-wide maximum non-             0
     cancer TOSHI greater than 1.......................
    Number of facilities at which the APR source                     0
     category contributes 50 percent or more to the
     facility-wide maximum non-cancer TOSHI of 1 or
     more..............................................
------------------------------------------------------------------------

    The facility-wide MIR from all HAP emissions at a facility that 
contains sources subject to the APR MACT standards is estimated to be 
9-in-1 million, based on actual emissions. There are 10 facilities with 
facility-wide MIR of 1-in-1 million or greater, and 7 of these 
facilities have APR production operations that contribute greater than 
50 percent to the facility-wide risks.
    The facility-wide maximum individual chronic non-cancer TOSHI is 
estimated to be 0.2 based on actual emissions.
6. What demographic groups might benefit from this regulation?
    To determine whether or not to conduct a demographics analysis, 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. For the APR source category, our analyses show that 
actual emissions from the APR 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 0.001 cases per year. 
Therefore, we did not conduct an assessment of risks to individual 
demographic groups for this rulemaking. 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.''

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

1. Risk Acceptability
    As noted in section III.B of this preamble, we weigh all health 
risk factors in our risk acceptability determination, including the 
MIR; the number of persons in various risk ranges; cancer incidence; 
the maximum non-cancer HI; the maximum acute non-cancer HQ; the extent 
of non-cancer risks; the potential for adverse environmental effects; 
distribution of risks in the exposed population; and risk estimation 
uncertainty (54 FR 38044, September 14, 1989). For the APR 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 10-in-1 million due to allowable 
emissions. These values are considerably less than 100-in-1 million, 
which is the presumptive level of acceptability. The risk analysis also 
shows low cancer incidence (1 in every 1,000 years), low potential for 
human health multipathway effects, and that chronic non-cancer health 
impacts are unlikely.
    We estimate that the worst-case acute HQ could exceed 1 for one 
HAP, formaldehyde, with a potential maximum HQ up to 10 based on the 
acute REL for formaldehyde. Three of the 18 facilities in this source 
category had an estimated HQ greater than 1. The maximum HQ based on an 
AEGL-1 is 0.5, based on the AEGL-1 for formaldehyde. As described 
earlier in this preamble, the acute assessment includes some 
conservative assumptions and some uncertainties. Considering the 
improbable assumption that worst-case meteorological conditions are 
present at the same time that maximum hourly emissions of formaldehyde 
exceed the average hourly emission rate by a factor of 10 at most 
emission points simultaneously, coincident with individuals being in 
the location of maximum impact, and considering the low acute HQ values 
based on the AEGL-1 collectively with the REL value, we believe that it 
is unlikely that HAP emissions from this source category would result 
in adverse acute health effects. Further discussion on these 
assumptions can be found in the Draft Residual Risk Assessment for the 
Amino/Phenolic Resins Production Source Category, which is available in 
the docket for this action.
    Our screening level evaluation of the potential health risks 
associated with emissions of PB-HAP indicates low potential for adverse 
multipathway impacts due to emissions of the PB-HAP associated with the 
source category. The Draft Residual Risk Assessment for the Amino/
Phenolic Resins Production Source Category in the docket also discusses 
the screening level evaluation.
    Our additional analysis of facility-wide risks showed that the 
maximum facility-wide cancer risk is 9-in-1 million. The maximum 
chronic non-cancer TOSHI is estimated to be 0.2.
    The EPA has weighed the various health risk measures and health 
factors, including risk estimation uncertainty, discussed above and in 
section III.A.8 of this preamble, and we are proposing to determine 
that the risks from the APR source category are acceptable.
2. Ample Margin of Safety Analysis
    Although we are proposing to determine that the risks from the APR 
source category are acceptable, risk estimates for 6,300 individuals in 
the exposed population are above 1-in-1 million. Consequently, we 
considered whether the APR MACT standards provide an ample margin of 
safety to protect public health. In this analysis, we investigated 
available emissions control options that might reduce the risk 
associated with emissions from the source category and considered this

[[Page 1706]]

information along with all of the health risks and other health 
information considered in the risk acceptability determination.
    For the APR source category, we did not identify any further 
control options for equipment leaks, storage vessels, continuous 
process vents, batch process vents or heat exchange systems beyond what 
is currently required in the rule or what we considered for proposal in 
this action (see section V.A of this preamble for our proposed actions 
related to storage vessels and continuous process vents).
    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 additional factors 
relating to the appropriate level of control, including the costs and 
economic impacts of emissions controls, technological feasibility, 
uncertainties and other relevant factors in making our ample margin of 
safety determination. Considering all of these factors, the EPA is 
proposing to determine that the current MACT standards in 40 CFR part 
63, subpart OOO for the APR source category provide an ample margin of 
safety to protect public health.
3. Adverse Environmental Effects
    Based on the results of our environmental risk screening 
assessment, we do not expect there to be an adverse environmental 
effect as a result of HAP emissions from the APR source category. We 
are proposing to determine that it is not necessary to set a more 
stringent standard to prevent, taking into consideration costs, energy, 
safety, and other relevant factors, an adverse environmental effect.

D. What are the results and proposed decisions based on our technology 
review?

    In the period of time since the APR MACT standards were 
promulgated, the EPA has developed air toxics regulations for numerous 
source categories that emit organic HAP from the same type of emissions 
sources that are present in the APR source category. We reviewed the 
regulatory requirements and technical analyses for these regulations 
for new practices, processes, and control techniques. We also conducted 
a search of the BACT/RACT/LAER clearinghouse for controls for VOC- and 
HAP-emitting processes in the Polymers and Resins and the SOCMI 
categories with permits dating back to 1997.
    For storage vessels located at new sources, we identified two 
potential developments in existing practices and control techniques not 
currently required by the APR MACT standards. The current requirements 
for storage vessels at a new source are to maintain and operate either 
an internal or an external floating roof, or use a fixed roof tank with 
emissions vented through a closed vent system to any combination of 
control devices that achieve a 95 percent emissions reduction or reduce 
emissions to specified control device outlet concentrations. These 
requirements apply to storage vessels having a capacity of 50,000 
gallons or greater and a vapor pressure of 2.45 psia or greater, or a 
capacity of 90,000 gallons or greater and a vapor pressure of 0.15 psia 
or greater. As in the identified beyond-the-floor options for existing 
storage vessels in the APR source category, we evaluated revising the 
applicability of the APR new source MACT requirements to include 
smaller capacity storage vessels and/or storage vessels containing 
liquids with lower vapor pressures (Option 1), and under Option 2 we 
considered the impacts of requiring a 98 percent emissions reduction 
for storage vessels meeting the capacity and vapor pressure thresholds 
of Option 1. Under Options 1 and 2, we evaluated the impacts of 
changing the thresholds at which emissions controls are required to be 
consistent with other storage vessel standards already required for the 
chemical industry regulated by the HON. Specifically, as shown in Table 
13, under this option, we evaluated requiring the new source level of 
emissions control for storage vessels of capacities greater than or 
equal to 20,000 gal, but less than 40,000 gal if the MTVP is 1.9 psia 
or greater, and for storage vessels of capacities greater than or equal 
to 40,000 gal, but less than 90,000 gal if the MTVP is 0.75 psia or 
greater. Control would still be required for storage vessels of 90,000 
gal or greater, if the MTVP is 0.15 psia or greater, as currently 
required for storage vessels at new sources in the APR source category, 
but which is not a requirement of the HON. Since available data for the 
source category indicates most APR storage vessels have fixed-roofs, 
under Option 2, we considered the impacts of requiring a 98 percent 
emissions reduction for storage vessels meeting the capacity and vapor 
pressure thresholds under Option 1, assuming a RTO would be used to 
attain this increased level of control.
    Table 14 presents the impacts of the options considered for storage 
vessels at a new source in the APR source category under the technology 
review. Since there are currently no new sources in the APR source 
category, this analysis was conducted based on a single model APR 
facility. As seen by the incremental cost effectiveness column in Table 
14 of this preamble, for Option 1, we estimated the capital costs to be 
approximately $11,000, and the total annualized costs are estimated to 
be approximately $2,500. The estimated HAP emissions reduction is 
approximately 1.1 tpy, and the cost effectiveness is approximately 
$2,400/ton. For Option 2, we estimated the capital costs to be 
approximately $590,000, and the total annualized costs are estimated to 
be approximately $170,000. The estimated HAP emissions reduction is 
approximately 1.2 tpy, and the incremental cost effectiveness between 
Option 1 and Option 2 is approximately $1.43 million/ton.

  Table 13--Storage Tank Size and Vapor Pressure Thresholds Considered
               Under the Technology Review for New Sources
------------------------------------------------------------------------
                                  Size and vapor pressure thresholds for
                                                  control
     Regulatory alternatives     ---------------------------------------
                                                         Vapor pressure
                                     Size (gallons)          (psia)
------------------------------------------------------------------------
Current MACT Requirements.......  50,000 =2.45
                                  90,000 =0.15
Options 1 and 2.................  20,000 =1.9
                                   =0.75
                                   =0.15
------------------------------------------------------------------------

[[Page 1707]]

  Table 14--Facility Emissions Reduction and Cost Impacts of Control Options for Storage Vessels at a Model New
                                                  APR Facility
----------------------------------------------------------------------------------------------------------------
                                                                                    Cost        Incremental cost
                              HAP  emissions   Capital cost   Annual cost ($/   effectiveness     effectiveness
   Regulatory alternatives       reduction          ($)             yr)          ($/ton HAP        ($/ton HAP
                                   (tpy)                                          removed)          removed)
----------------------------------------------------------------------------------------------------------------
Option 1....................            1.05          11,200           2,500             2,370
Option 2....................            1.17         590,000         171,000           146,000         1,430,000
----------------------------------------------------------------------------------------------------------------

    Based on this analysis, we believe the costs of Option 1 are 
reasonable, given the level of HAP emissions reduction that would be 
achieved with these control options. We believe that the costs of 
Option 2 are not reasonable, given the level of HAP emission reduction 
they would achieve. Therefore, we are proposing to revise the APR MACT 
standards to require the current level of control for storage vessels 
at new sources with the specified capacities and vapor pressures for 
Option 1.
    For equipment leaks, continuous process vents, batch process vents 
and heat exchange systems, beyond what is currently required in the 
rule or is being proposed in this action, we did not identify: any add-
on control technology or other equipment that was not identified and 
considered during MACT development; any improvements in add-on control 
technology or other equipment (that was identified and considered 
during MACT development) that could result in significant additional 
HAP emission reduction; any work practice or operational procedure that 
was not identified and considered during MACT development; any process 
change or pollution prevention alternative that could be broadly 
applied that was not identified and considered during MACT development; 
or any significant changes in the cost (including cost effectiveness) 
of applying controls (including controls the EPA considered during MACT 
development).
    For more detailed information on the results of the EPA's 
technology review, see the memorandum, Developments in Practices, 
Processes, and Control Technologies for the Amino/Phenolic Resins 
Production Source Category available in the docket for this action 
(EPA-HQ-OAR-2012-0133).

VI. Analytical Results and Proposed Decisions for the PC Source 
Category

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

1. Inhalation Risk Assessment Results
    Table 15 provides an overall summary of the inhalation risk 
assessment results for the source category.

                                                     Table 15--PC Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                    Maximum individual cancer risk                                    Maximum chronic non-cancer
                                          (in 1 million) \2\                         Annual cancer             TOSHI \3\
                                   --------------------------------  Population at     incidence   --------------------------------   Maximum off-site
     Number of facilities \1\           Actual         Allowable    risk >= 1-in-1    (cases per        Actual         Allowable     acute non-cancer HQ
                                       emissions       emissions        million          year)         emissions       emissions             \4\
                                         level           level                                           level           level
--------------------------------------------------------------------------------------------------------------------------------------------------------
4.................................            0.3             0.3               0         0.00008            0.04            0.04   HQREL = 2
                                                                                                                                     triethylamine.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk.
\3\ Maximum TOSHI. The target organ with the highest TOSHI for the PC source category is the respiratory system.
\4\ The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop an array of HQ values. HQ values
  shown use the lowest available acute threshold value, which in most cases is the REL. When HQ values exceed 1, we also show HQ values using the next
  lowest available acute dose-response value. See section III.A.3 of this preamble for explanation of acute dose-response values.

    The inhalation risk modeling was performed using actual emissions 
level data. As shown in Table 15, the results of the inhalation risk 
assessment indicated the maximum lifetime individual cancer risk could 
be up to 0.3-in-1 million, the estimated maximum chronic non-cancer 
TOSHI value is 0.04 and the estimated maximum off-facility site acute 
HQ value is 2, based on the actual emissions level and the REL value 
for triethylamine. The total estimated national cancer incidence from 
these facilities based on actual emission levels is 0.00008 excess 
cancer cases per year or one case in every 13,000 years.
    Based on our analysis, we estimate that the MACT-allowable 
emissions level for organic HAP emissions from certain storage vessels 
could be up to 2.5 times the actual emissions from this source 
category. However, as we estimate that storage vessel emissions 
contribute only 5 percent to the total organic HAP emissions for the 
source category, the application of the factor of 2.5 to the organic 
HAP emissions from these sources resulted in essentially no increase in 
cancer risks, as the risk increase is so small that when the risk value 
is rounded to one significant digit, there is no change. Therefore, the 
cancer risk results for MACT-allowable emissions are approximately 
equal to those for actual emissions. For more detail about this 
estimate of the ratio of actual to MACT-allowable emissions and the 
estimation of MACT-allowable emission levels (and associated risks and 
impacts), see the memorandum, MACT Allowable Emissions and Risks for 
the Acrylic and Modacrylic Fibers, Amino/Phenolic Resins, and 
Polycarbonate Production Source Categories, in the docket for this 
action.
2. Acute Risk Results
    We estimate that the maximum off-facility site acute HQ value is 2, 
based on the actual emissions level and the REL value for 
triethylamine.
3. Multipathway Risk Screening Results
    There were no reported emissions of PB-HAP, indicating low 
potential for human health multipathway risks as a

[[Page 1708]]

result of PB-HAP emissions from this source category.
4. Environmental Risk Screening Results
    The emissions data for the PC source category indicate that sources 
within this source category do not emit any of the seven pollutants 
that we identified as ``environmental HAP,'' as discussed earlier in 
this preamble. Based on the processes and materials used in the source 
category, we do not expect any of the seven environmental HAP to be 
emitted. Also, we are unaware of any adverse environmental effect 
caused by emissions of HAP that are emitted by this source category. 
Therefore, we do not expect an adverse environmental effect as a result 
of HAP emissions from this source category.
5. Facility-Wide Risk Results
    Table 16 displays the results of the facility-wide risk assessment 
for the PC source category. This assessment was conducted based on 
actual emission levels. For detailed facility-specific results, see 
Appendix 4 of the Draft Residual Risk Assessment for the Polycarbonate 
Production Source Category in the docket for this action.

           Table 16--PC Facility-Wide Risk Assessment Results
------------------------------------------------------------------------
 
------------------------------------------------------------------------
Number of facilities analyzed...........................               4
Cancer Risk:
    Estimated maximum facility-wide individual cancer                 20
     risk (in 1 million)................................
    Number of facilities with estimated facility-wide                  0
     individual cancer risk of 100-in-1 million or more.
    Number of facilities at which the PC source category               0
     contributes 50 percent or more to the facility-wide
     individual cancer risks of 100-in-1 million or more
    Number of facilities at which the PC source category               0
     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......               2
    Number of facilities with facility-wide maximum non-               1
     cancer TOSHI greater than 1........................
    Number of facilities at which the PC source category               0
     contributes 50 percent or more to the facility-wide
     maximum non-cancer TOSHI of 1 or more..............
------------------------------------------------------------------------

    The facility-wide MIR from all HAP emissions at a facility that 
contains sources subject to the PC MACT standards is estimated to be 
20-in-1 million, based on actual emissions. Of the 4 facilities 
included in this analysis, none have a facility-wide MIR of 100-in-1 
million. There are 2 facilities with facility-wide MIR of 1-in-1 
million or greater. Neither of these facilities have PC production 
operations that contribute greater than 50 percent to the facility-wide 
risks.
    The facility-wide maximum individual chronic non-cancer TOSHI is 
estimated to be 2 based on actual emissions. Of the 4 facilities 
included in this analysis, one has facility-wide maximum chronic non-
cancer TOSHI values greater than or equal to 1.
6. What demographic groups might benefit from this regulation?
    To determine whether or not to conduct a demographics analysis, 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. For the PC source category, our analyses show that 
actual emissions from the PC source category result in no individuals 
being exposed to cancer risk greater than 1-in-1 million or a non-
cancer TOSHI greater than 1. Therefore, we did not conduct an 
assessment of risks to individual demographic groups for this 
rulemaking. 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 noted in section III.B of this preamble, we weigh all health 
risk factors in our risk acceptability determination, including the 
MIR; the number of persons in various risk ranges; cancer incidence; 
the maximum non-cancer HI; the maximum acute non-cancer HQ; the extent 
of non-cancer risks; the potential for adverse environmental effects; 
distribution of risks in the exposed population; and risk estimation 
uncertainty (54 FR 38044, September 14, 1989). For the PC source 
category, the risk analysis we performed indicates that the cancer 
risks to the individual most exposed could be up to 0.3-in-1 million 
due to both actual and allowable emissions. This value is considerably 
less than 100-in-1 million, which is the presumptive level of 
acceptability. The risk analysis also shows low cancer incidence (1 in 
every 13,000 years), low potential for human health multipathway 
effects because no PB-HAP are emitted from this source category, and 
that chronic non-cancer health impacts are unlikely.
    We estimate that the worst-case acute HQ could exceed 1 for one 
HAP, triethylamine, with a potential maximum HQ up to 2 based on the 
acute REL for triethylamine. One of the 4 facilities in this source 
category had an estimated HQ greater than 1. As described earlier in 
this preamble, the acute assessment includes some conservative 
assumptions and some uncertainties. Considering the improbable 
assumption that worst-case meteorological conditions are present at the 
same time that maximum hourly emissions formaldehyde exceed the average 
hourly emission rate by a factor of 10 at most emission points 
simultaneously, and coincident with individuals being in the location 
of maximum impact, we believe that it is unlikely that HAP emissions 
from this source category would result in adverse acute health effects. 
Further discussion on these assumptions can be found in the Draft 
Residual Risk Assessment for the Polycarbonate Production Source 
Category, which is available in the docket for this action.
    Our additional analysis of facility-wide risks showed that the 
maximum facility-wide cancer risk is 20-in-1 million and the maximum 
chronic non-cancer TOSHI is estimated to be 2. The source category 
contributes less than 1 percent to the maximum facility-wide cancer 
risk and less than 1 percent to the maximum facility-wide TOSHI.
    The EPA has weighed the various health risk measures and health 
factors, including risk estimation uncertainty, discussed above and in 
section III.A.8 of

[[Page 1709]]

this preamble, and we are proposing to determine that the risks from 
the PC source category are acceptable.
2. Ample Margin of Safety Analysis
    The PC source category emits HAP which are known, probable or 
possible carcinogens. The EPA evaluated the emissions of these HAP and 
estimates that the cancer risks to the individual most exposed are less 
than 1-in-1 million, based on actual and MACT-allowable emissions. Our 
analysis also indicates that chronic non-cancer risks are low, based on 
actual and MACT-allowable emissions. We estimate that emissions from 
the PC source category would result in a maximum chronic non-cancer 
TOSHI less than 1 for the individual most exposed. While the assessment 
for acute impacts suggests that short-term triethylamine concentrations 
at one facility could exceed the REL, we believe it unlikely that acute 
impacts would occur due to the conservative assumptions and 
uncertainties associated with the acute analysis. These assumptions 
include having worst-case meteorological conditions present at the same 
time that maximum hourly emissions of triethylamine exceed the average 
hourly emission rate by a factor of 10, coincident with individuals 
being in the location of maximum impact.
    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 additional factors 
relating to the appropriate level of control, including the costs and 
economic impacts of emissions controls, technological feasibility, 
uncertainties and other relevant factors in making our ample margin of 
safety determination. Considering all of these factors, the EPA is 
proposing to determine that the current MACT standards in 40 CFR part 
63, subpart YY for the PC source category provide an ample margin of 
safety to protect public health.
3. Adverse Environmental Effects
    We did not identify emissions of the seven environmental HAP 
included in our environmental risk screening, and are unaware of any 
adverse environmental effects caused by other HAP emitted by this 
source category. Therefore, we do not expect there to be an adverse 
environmental effect as a result of HAP emissions from this source 
category, and we are proposing to determine that it is not necessary to 
set a more stringent standard to prevent, taking into consideration 
costs, energy, safety, and other relevant factors, an adverse 
environmental effect.

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

    In the period of time since the PC MACT standards were promulgated, 
the EPA has developed air toxics regulations for numerous source 
categories that emit organic HAP from the same type of emissions 
sources that are present in the PC source category. We reviewed the 
regulatory requirements and technical analyses for these regulations 
for new practices, processes, and control techniques. We also conducted 
a search of the BACT/RACT/LAER clearinghouse for controls for VOC- and 
HAP-emitting processes in the Polymers and Resins and the SOCMI 
categories with permits dating back to 1997.
    The PC MACT standards currently require compliance with either 
subpart TT or subpart UU of 40 CFR part 63 to control emissions from 
equipment leaks. While many of the provisions of these two rules are 
the same or similar, subpart UU requires the use of a lower leak 
definition for valves in gas and vapor service and in light liquid 
service, pumps in light liquid service, and connectors in gas and vapor 
service and in light liquid service. Specifically, subpart UU lowers 
the leak definition for valves from 10,000 ppm (in subpart TT) to 500 
ppm, lowers the leak definition for pump seals from 10,000 ppm (in 
subpart TT) to 1,000 ppm, and requires instrument monitoring of 
connectors with a leak definition of 500 ppm, as opposed to sensory 
monitoring (in subpart TT). We identified the more stringent leak 
definitions of subpart UU as a development in practices, processes or 
control technologies for LDAR programs.
    Assuming that each of the four PC sources currently comply with 
subpart TT, we analyzed the costs and emission reductions associated 
with switching from a subpart TT LDAR program to a subpart UU LDAR 
program, both including and not including the subpart UU connector 
monitoring requirements, which can be an expensive component of an LDAR 
program. The estimated costs and emissions reductions associated with 
these options are shown in Table 17. For Option 1 (subpart UU without 
connector monitoring), we estimated the capital costs to be 
approximately $16,000, and the total annualized costs are estimated to 
be approximately $2,200. The estimated HAP emissions reduction is 
approximately 2.1 tpy, and the cost effectiveness is approximately 
$1,000/ton. For Option 2 (subpart UU with connector monitoring), we 
estimated the capital costs to be approximately $93,000, and the total 
annualized costs are estimated to be approximately $32,000. The 
estimated HAP emissions reduction is approximately 4.4 tpy, and the 
cost effectiveness is approximately $7,400/ton. The incremental cost 
effectiveness between Option 1 and Option 2 is approximately $13,000.
    While, as discussed in section VI.B above, the equipment leaks 
control options are not needed to support the EPA's finding under CAA 
section 112(f) that the PC MACT standards already protect public health 
with an ample margin of safety, and while we do not factor quantified 
risk reductions into CAA section 112(d)(6) technology review analyses, 
for informational purposes we note that neither Option 1 nor Option 2 
for equipment leaks would reduce the MIR for the source category 
because the MIR is not caused by emissions from equipment leaks. 
However, the maximum chronic non-cancer TOSHI is due to emissions from 
equipment leaks. At the MACT-allowable emissions level, under Option 1, 
the TOSHI would be reduced from 0.04 to 0.03, and under Option 2, the 
TOSHI would be reduced to 0.02.

                                   Table 17--PC Equipment Leak Options Impacts
----------------------------------------------------------------------------------------------------------------
                               HAP emissions                                        Cost        Incremental cost
   Regulatory alternatives       reduction     Capital cost   Annual cost ($/ effectiveness ($/ effectiveness ($/
                                   (tpy)            ($)             yr)       ton HAP removed)  ton HAP removed)
----------------------------------------------------------------------------------------------------------------
Option 1: Subpart UU, no                 2.1          16,000           2,200             1,000
 connector monitoring.......
Option 2: Subpart UU with                4.4          93,000          32,000             7,400            13,000
 connector monitoring.......
----------------------------------------------------------------------------------------------------------------

[[Page 1710]]

    Based on this analysis, we believe the costs of Option 1 are 
reasonable, given the level of HAP emissions reduction that would be 
achieved with this control option. We believe the costs of Option 2 are 
not reasonable, given the level of HAP emission reduction that control 
option would achieve. Therefore, we are proposing to revise the PC MACT 
standards to require facilities to comply with subpart UU rather than 
subpart TT, with the exception of connectors in gas and vapor service 
and in light liquid service. We are proposing to retain the option to 
comply with either subpart TT or subpart UU for these components.
    For storage vessels, process vents and wastewater treatment 
systems, beyond what is currently required in the rule or is being 
proposed in this action, we did not identify: Any add-on control 
technology or other equipment that was not identified and considered 
during MACT development; any improvements in add-on control technology 
or other equipment (that was identified and considered during MACT 
development) that could result in significant additional HAP emission 
reduction; any work practice or operational procedure that was not 
identified and considered during MACT development; any process change 
or pollution prevention alternative that could be broadly applied that 
was not identified and considered during MACT development; or any 
significant changes in the cost (including cost effectiveness) of 
applying controls (including controls the EPA considered during MACT 
development).
    For more detailed information on the results of the EPA's 
technology review, see the memorandum, Developments in Practices, 
Processes, and Control Technologies for the Polycarbonate Production 
Source Category, available in the docket for this action (EPA-HQ-OAR-
2012-0133).

VII. What other actions are we proposing?

    In addition to the proposed changes to the standards described 
above, we reviewed the MACT standards to determine whether we should 
make additional amendments. From this review we have identified four 
additional revisions. First, we are proposing revisions to the SSM 
provisions of the MACT rule in order 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. As part of these SSM revisions, we are 
proposing to require monitoring of PRD in organic HAP service that 
release to the atmosphere. Second, we are proposing revisions to 
require electronic reporting of emissions test results. Third, we are 
proposing to add a definition of ``seal'' to all three rules. Finally, 
we are seeking comments on the performance of flares in these source 
categories. We present details and the rationale for the proposed 
changes related to these issues in the following sections.

A. Startup, Shutdown and Malfunction

    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008), cert. denied, 130 S. Ct. 1735 (U.S. 2010), 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 the elimination of the SSM exemption in the rules 
regulating each of the three source categories addressed by this rule. 
Consistent with Sierra Club v. EPA, we are proposing that the standards 
in these rules apply at all times. We are also proposing several 
revisions to Subpart YY and Table 1 to Subpart OOO (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 ensure that the provisions we are 
proposing to eliminate are inappropriate, unnecessary or redundant in 
the absence of the SSM exemption. We are specifically seeking comment 
on whether we have successfully done so.
    In proposing the standards in these rules, the EPA has taken into 
account startup and shutdown periods and has not proposed alternate 
standards for those periods because facilities in these source 
categories have not indicated that they will be unable to comply with 
the standards during these times. Emission reductions for process vents 
and transfer operations are typically achieved by routing vapors to a 
control device such as a thermal oxidizer or carbon adsorber. It is 
common practice to start a control device prior to startup of the 
emissions source it is controlling, so the control device would be 
operating before emissions are routed to it. We expect control devices 
would be operating during startup and shutdown events in a manner 
consistent with normal operating periods, and that these control 
devices will be operated to maintain and meet the monitoring parameter 
operating limits set during the performance test. We do not expect 
startup and shutdown events to affect emissions from equipment leaks, 
wastewater sources (e.g., surface impoundments, oil-water separators, 
organic-water separators) or storage tanks. Leak detection programs 
associated with equipment leaks are in place to detect leaks, and 
therefore, it is inconsequential whether the process is operating under 
normal operating conditions or is in startup or shutdown. Wastewater 
emissions are also not expected to be significantly affected by startup 
or shutdown events. Working and breathing losses from storage tanks are 
the same regardless of whether the process is operating under normal 
operating conditions or if it is in a startup or shutdown event.
    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 
CAA section 112 that directs the agency to consider malfunctions in 
determining the level ``achieved'' by the best-performing or best-
controlled sources when setting emission standards. Moreover, while the 
EPA accounts for variability in setting emissions standards consistent 
with the section 112 case law, nothing in that case law requires the 
agency to consider malfunctions as part of that analysis.

[[Page 1711]]

Section 112 of the CAA uses the concept of ``best-controlled'' and 
``best-performing'' unit in defining the level of stringency that 
section 112 performance standards must meet. Applying the concept of 
``best-controlled'' or ``best-performing'' to a unit that is 
malfunctioning presents significant difficulties, as malfunctions are 
sudden and unexpected events.
    Further, accounting for malfunctions would be difficult, if not 
impossible, given the 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. 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.'' See 40 CFR 63.2, definition of 
malfunction.
    Finally, the EPA recognizes that even equipment that is properly 
designed and maintained can sometimes fail and that such failure can 
sometimes cause a violation of an emission standard. See, e.g., State 
Implementation Plans: Response to Petition for Rulemaking; Findings of 
Excess Emissions During Periods of Startup, Shutdown, and Malfunction; 
Proposed rule, 78 FR 12460 (Feb. 22, 2013); State Implementation Plans: 
Policy Regarding Excessive Emissions During Malfunctions, Startup, and 
Shutdown (September 20, 1999); Policy on Excess Emissions During 
Startup, Shutdown, Maintenance, and Malfunctions (February 15, 1983). 
The EPA is therefore proposing to add an affirmative defense to civil 
penalties for violations of emission standards in these rules that are 
caused by malfunctions. (See proposed 40 CFR 63.1100(h) and 40 CFR 
63.1400(l) defining ``affirmative defense'' to mean, in the context of 
an enforcement proceeding, a response or defense put forward by a 
defendant, regarding which the defendant has the burden of proof, and 
the merits of which are independently and objectively evaluated in a 
judicial or administrative proceeding).
    We also are proposing other regulatory provisions to specify the 
elements that are necessary to establish this affirmative defense; the 
source must prove by a preponderance of evidence that it has met all of 
the elements set forth in proposed 40 CFR 63.1100(h) and 40 CFR 
63.1400(l). (See 40 CFR 22.24). The proposed criteria are designed in 
part to ensure that the affirmative defense is available only where the 
event that causes a violation of the emission standard meets the narrow 
definition of malfunction in 40 CFR 63.2 (sudden, infrequent, not 
reasonably preventable and not caused by poor maintenance and/or 
careless operation). For example, to successfully assert the proposed 
affirmative defense, the source must prove by a preponderance of the 
evidence that the violation ``[w]as caused by a sudden, infrequent, and 
unavoidable failure of air pollution control, process equipment, or a 
process to operate in a normal or usual manner . . . .'' The proposed 
criteria also are designed to ensure that steps are taken to correct 
the malfunction, to minimize emissions in accordance with proposed 40 
CFR 63.1108(a)(4)(ii) and 40 CFR 63.1400(k)(4) and to prevent future 
malfunctions. For example, under the proposed criteria, the source must 
prove by a preponderance of the evidence that ``[r]epairs were made as 
expeditiously as possible when a violation occurred[hellip]'' and that 
``[a]ll possible steps were taken to minimize the impact of the 
violation on ambient air quality, the environment and human health . . 
. .'' Under the proposal, in any judicial or administrative proceeding, 
the Administrator may challenge the assertion of the affirmative 
defense and, if the respondent has not met its burden of proving all of 
the requirements in the affirmative defense, appropriate penalties may 
be assessed in accordance with section 113 of the CAA (see also 40 CFR 
22.27).
    The EPA is proposing to include an affirmative defense in an 
attempt to balance a tension, inherent in many types of air regulation, 
to ensure adequate compliance while simultaneously recognizing that 
despite the most diligent of efforts, emission standards may be 
violated under circumstances beyond the control of the source. The EPA 
must establish emission standards that ``limit the quantity, rate, or 
concentration of emissions of air pollutants on a continuous basis.'' 
CAA section 302(k), 42 U.S.C. 7602(k) (defining ``emission limitation'' 
and ``emission standard''). See, generally, Sierra Club v. EPA, 551 
F.3d 1019, 1021 (D.C. Cir. 2008). Thus, the EPA is required to ensure 
that emissions standards are continuous. The affirmative defense for 
malfunction events meets this requirement by ensuring that even where 
there is a malfunction, the emission standard is still enforceable 
through injunctive relief. The United States Court of Appeals for the 
Fifth Circuit recently upheld the EPA's view that an affirmative 
defense provision is consistent with section 113(e) of the CAA. 
Luminant Generation Co. LLC v. United States EPA, 714 F.3d 841 (5th 
Cir. Mar. 25, 2013) (upholding the EPA's approval of affirmative 
defense provisions in a CAA State Implementation Plan). While 
``continuous'' standards are required, there is also case law 
indicating that in many situations it is appropriate for the EPA to 
account for the practical realities of technology. For example, in 
Essex Chemical v. Ruckelshaus, 486 F.2d 427, 433 (D.C. Cir. 1973), the 
D.C. Circuit acknowledged that in setting standards under CAA section 
111 ``variant

[[Page 1712]]

provisions'' such as provisions allowing for upsets during startup, 
shutdown and equipment malfunction ``appear necessary to preserve the 
reasonableness of the standards as a whole and that the record does not 
support the `never to be exceeded' standard currently in force.'' See 
also, Portland Cement Association v. Ruckelshaus, 486 F.2d 375 (D.C. 
Cir. 1973). Though these earlier cases may no longer represent binding 
precedent in light of the CAA 1977 amendments and intervening case law 
such as Sierra Club v. EPA, they nevertheless support the EPA's view 
that a system that incorporates some level of flexibility is reasonable 
and appropriate.
    The affirmative defense simply provides for a defense to civil 
penalties for violations that are proven to be beyond the control of 
the source. Through the proposed incorporation of an affirmative 
defense, the EPA is proposing to formalize its approach to 
malfunctions. In a Clean Water Act setting, the Ninth Circuit required 
this type of formalized approach when regulating ``upsets beyond the 
control of the permit holder.'' Marathon Oil Co. v. EPA, 564 F.2d 1253, 
1272-73 (9th Cir. 1977). See also, Mont. Sulphur & Chem. Co. v. EPA, 
666 F.3d 1174 (9th Cir. 2012) (rejecting industry argument that 
reliance on the affirmative defense was not adequate). But see, 
Weyerhaeuser Co. v. Costle, 590 F.2d 1011, 1057-58 (D.C. Cir. 1978) 
(holding that an informal approach is adequate). The proposed 
affirmative defense provisions would give the EPA the flexibility to 
both ensure that its emission standards are ``continuous,'' as required 
by 42 U.S.C. 7602(k), and account for unplanned upsets and, thus, 
support the reasonableness of the standard as a whole.
    The EPA is proposing the affirmative defense applicable to 
malfunctions under the delegation of general regulatory authority set 
out in section 301(a)(1) of the CAA, 42 U.S.C. 7601(a)(1), in order to 
balance this tension between provisions of the CAA and the practical 
reality, as case law recognizes, that technology sometimes fails. See 
generally, Citizens to Save Spencer County v. U.S. Environmental 
Protection Agency, 600 F.2d 844, 873 (D.C. Cir. 1979) (using section 
301(a) authority to harmonize inconsistent guidelines related to the 
implementation of federal preconstruction review requirements).
1. General Duty
    For the APR MACT standards, we are proposing to revise the General 
Provisions applicability table (Table 1 to Subpart OOO) entry for 40 
CFR 63.6(e)(1)(i) by changing the explanation in column 3. 40 CFR 
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. Similarly, for the AMF 
and PC source categories, we are also proposing to remove this 
requirement at 40 CFR 63.1108(a)(5). For the AMF, APR and PC MACT 
standards, we are proposing instead to add general duty regulatory text 
at 40 CFR 63.1108(a)(4)(ii) and 63.1400(k)(4) that reflects the 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 63.1108(a)(4)(ii) and 
63.1400(k)(4) does not include that language from 40 CFR 63.6(e)(1).
    For the APR MACT standards, we are also proposing to revise the 
General Provisions applicability table (Table 1 to Subpart OOO) entry 
for 40 CFR 63.6(e)(1)(ii) by changing the ``yes'' in the second column 
to a ``no.'' 40 CFR 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 40 CFR 63.1400(k)(4).
2. SSM Plan
    For the APR MACT standards, we are proposing to revise the General 
Provisions applicability table (Table 1 to Subpart OOO) entry for 40 
CFR 63.6(e)(3) by changing the ``yes'' in the second column to a 
``no.'' Similarly, for the AMF and PC source categories, we are also 
proposing to remove this requirement at 40 CFR 63.1111(a). Generally, 
these paragraphs require development of an SSM plan and specify 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.
3. Compliance With Standards
    For the APR MACT standards, we are proposing to revise the General 
Provisions applicability table (Table 1 to Subpart OOO) entry for 40 
CFR 63.6(f)(1) by changing the ``yes'' in the second column 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.
4. Performance Testing
    For the APR MACT standards, we are proposing to revise the General 
Provisions applicability table (Table 1 to Subpart OOO) entry for 40 
CFR 63.7(e)(1) by changing the ``yes'' in the second column to a 
``no.'' 40 CFR 63.7(e)(1) describes performance testing requirements. 
Similarly, for the AMF and PC source categories, we are also proposing 
to revise this requirement at 40 CFR 63.1108(b)(4)(ii).
    For the AMF, APR and PC MACT standards, the EPA is instead 
proposing to add a performance testing requirement at 40 CFR 
1108(b)(4)(ii) and 63.1413(a)(2). 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 and language that precluded startup and shutdown periods from 
being considered ``representative'' for purposes of performance 
testing. The proposed performance testing provisions do not allow 
performance testing during periods of startup or shutdown. As in 40 CFR 
63.7(e)(1), performance tests conducted under this subpart should not 
be conducted during malfunctions because conditions during malfunctions 
are not representative of normal operating conditions. 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. Currently, 40 
CFR 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'' available to the Administrator upon 
request, but does not specifically require the information to be 
recorded. The regulatory text the EPA is proposing to add to this

[[Page 1713]]

provision builds on that requirement and makes explicit the requirement 
to record the information.
5. Monitoring
    For the APR MACT standards, we are proposing to revise the General 
Provisions applicability table (Table 1 to Subpart OOO) entry for 40 
CFR 63.8(c)(1)(i) and (iii) by changing the ``yes'' in the second 
column 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)).
6. Recordkeeping
    For the AMF, APR and PC MACT standards, the EPA is proposing to add 
recordkeeping requirements during a malfunction to 40 CFR 63.1111(c)(1) 
and 63.1416(b). 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 
63.1111(c)(1) and 63.1416(b) 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.
7. Reporting
    For the APR MACT standards, we are proposing to revise the General 
Provisions applicability table (Table 1 to Subpart OOO) entry for 40 
CFR 63.10(d)(5) by changing the ``yes'' in the second column to a 
``no.'' Section 63.10(d)(5) describes the reporting requirements for 
startups, shutdowns, and malfunctions. Similarly, for the AMF and PC 
source categories, we are also proposing to remove this requirement at 
40 CFR 63.1111(b).
    For the AMF, APR and PC MACT standards, to replace the General 
Provisions reporting requirement, the EPA is proposing to add reporting 
requirements to 40 CFR 63.1111(c)(2) and 63.1417(g). 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 periodic 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 volume 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 note that reporting a failure to meet an applicable standard 
could include malfunction events for which a source may choose to 
submit documentation to support an assertion of affirmative defense, 
consistent with the affirmative defense provisions we are proposing 
today. If a source provides all the material proposed in 40 CFR 
63.1100(h) and 63.1400(l) to support an affirmative defense, the source 
need not submit the same information two times in the same report. 
While assertion of an affirmative defense is not mandatory and would 
occur only if a source chooses to take advantage of the affirmative 
defense, the proposed affirmative defense also requires additional 
reporting that goes beyond these routine requirements related to a 
failure to meet an applicable standard for a reason other than a 
malfunction.
    For the APR MACT standards, we are proposing to revise the General 
Provisions applicability table (Table 1 to Subpart OOO) entry for 40 
CFR 63.10(d)(5)(ii) by changing the ``yes'' in the second column to a 
``no.'' 40 CFR 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 or 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.
8. Pressure Relief Devices
    For the AMF, PC and APR MACT standards, we are proposing, as part 
of our revisions to address periods of SSM in response to the 2008 
Sierra Club ruling, to specify that PRD in organic HAP service may not 
release to the atmosphere. To ensure compliance with this requirement, 
we are further proposing to require facility owners or operators in 
these three source categories to employ monitoring capable of (1) 
immediately alerting an operator when there is an atmospheric release 
from a PRD in organic HAP service and (2) recording the time and 
duration of each pressure release. Owners or operators would be 
required to report any pressure release and an estimate of the amount 
of organic HAP released to the atmosphere with the next periodic 
report.
    We believe that PRD releases that are vented directly to the 
atmosphere are caused by malfunctions. Emissions vented to the 
atmosphere by PRDs may contain HAP that are otherwise regulated under 
the MACT standards. In Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 
2008), the court determined that standards under CAA section 112(d) 
must provide for compliance at all times. Therefore, the proposed rule 
revisions provide that a pressure release from a PRD in organic HAP 
service, unless routed to a control device or process, is a violation 
of the emission standard. As with any malfunction event, an owner or 
operator may assert an affirmative defense against civil penalties for 
a malfunction causing a

[[Page 1714]]

pressure release from a PRD in organic HAP service to the atmosphere.
    Pressure release events from PRDs in organic HAP service to the 
atmosphere 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. Therefore, we are proposing to require that sources 
monitor PRDs in organic HAP service using a device or system that is 
capable of identifying and recording the time and duration of each 
pressure release and of notifying operators that a release has 
occurred. For purposes of estimating the costs of this requirement, we 
assumed that operators would install electronic indicators on each PRD 
in organic HAP service that vents to the atmosphere to identify and 
record the time and duration of each pressure release. However, owners 
or operators could use a range of methods to satisfy these 
requirements, including the use of a parameter monitoring system that 
may already have been in place on the process operating pressure that 
is sufficient to notify operators immediately that a pressure release 
is occurring, as well as recording the time and duration of that 
release.
    Based on our cost assumptions that the most expensive approach 
would be used, the nationwide capital cost of installing these monitors 
is $37,000, $400,000 and $51,000 for the AMF, APR and PC source 
categories, respectively. The total annualized cost of installing and 
operating these monitors is $5,300, $56,000 and $7,200 per year for the 
AMF, APR and PC source categories, respectively.

B. 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 or 
operators of AMF, APR and PC facilities submit electronic copies of 
required performance test and performance evaluation reports by direct 
computer-to-computer electronic transfer using EPA-provided software. 
These provisions are being proposed in 40 CFR 63.1110(a)(9) (for the 
AMF and PC MACT standards) and 40 CFR 63.1417(h)(9) (for the APR MACT 
standards). 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 CEDRI. The submitted report package will be stored 
in the CDX archive (the official copy of record) and the 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 (and/or performance 
evaluations) 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 already have performance test data in hand, 
another benefit to industry is that fewer or less substantial data 
collection requests in conjunction with prospective required residual 
risk assessments or technology reviews will be needed. 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 
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 112 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 or operators, to locate, collect and submit performance test 
data. In recent years, 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

[[Page 1715]]

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, and tribal agencies and 
the EPA significant time, money and effort while also improving the 
quality of emission inventories and air quality regulations.

C. Open-Ended Valves and Lines

    The AMF MACT standards at 40 CFR 63.1103(b)(3) and the PC MACT 
standards at 40 CFR 63.1103(d)(3) require an owner or operator to 
control emissions from equipment leaks according to the requirements of 
either 40 CFR part 63, subpart TT or subpart UU. The APR MACT standards 
at 40 CFR 63.1410 require that equipment leaks be controlled according 
to subpart UU and do not provide an option to comply with subpart TT. 
For open-ended valves and lines, both subpart TT and subpart UU require 
that the open end be equipped with a cap, blind flange, plug or second 
valve that ``shall seal the open end at all times.'' However, neither 
subpart (nor the AMF, APR or PC MACT standards) define ``seal'' or 
explain in practical and enforceable terms what constitutes a sealed 
open-ended valve or line. This has led to uncertainty on the part of 
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, they are not operating in a 
``sealed'' manner as the EPA interprets that term.
    In response to this uncertainty, we are proposing to amend 40 CFR 
63.1103(b)(2) (for the AMF MACT standards), 40 CFR 63.1402(b) (for the 
APR MACT standards) and 40 CFR 63.1103(d)(2) (for the PC MACT 
standards) to add a definition of ``seal.'' This proposed definition 
clarifies that, for the purpose of complying with the requirements of 
40 CFR 63.1033(b) of subpart UU, open-ended valves and lines are 
``sealed'' by the cap, blind flange, plug, or second valve when there 
are no detectable emissions from the open-ended valve or line at or 
above an instrument reading of 500 ppm. We solicit comments on this 
approach to reducing the compliance uncertainty associated with open-
ended valves and lines and our proposed definition of ``seal.''

D. Flare Performance

    In addition to our proposed actions under CAA sections 112(d) and 
(f) for the AMF, PC and APR source categories, we are seeking comments 
on the performance of flares to control HAP emissions in these source 
categories, as governed by the EPA's General Provisions at 40 CFR 
63.11(b). This is an issue that the EPA has recently begun studying. 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 assure good combustion 
efficiency. Based on feedback received from the external ad-hoc peer 
review panel, the EPA has since undertaken an initiative to go back and 
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, AMF, PC and APR sources may choose to use a flare to 
reduce emissions from storage vessels and process vents to comply with 
the MACT standards, but are not required to do so. Our records indicate 
the use of flares in only the APR and PC source categories. However, we 
do not have specific flare performance data for the AMF, PC and APR 
source categories. Therefore, we are not at this time prepared to 
propose any changes to the currently applicable regulations pertaining 
to the performance of flares in the AMF, PC and APR source categories, 
but we may revisit the issue in future notices. We solicit comments and 
additional information on flare performance specifically for the AMF, 
PC and APR source categories. Examples of information requested for 
these source categories include: Prevalence 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.

VIII. What compliance dates are we proposing?

    Under CAA section 112(d), for the three source categories being 
addressed in this action, the proposed compliance date for new and 
existing sources for the revised SSM requirements (other than PRD 
monitoring for existing sources) and electronic reporting requirements 
is the effective date of the final amendments. We are proposing these 
compliance dates because these requirements should be immediately 
implementable by the facilities upon the next occurrence of a 
malfunction or the performance of a performance test that is required 
to be submitted to the ERT. Available information suggests that the 
facilities should already be able to comply with the existing standards 
during periods of startup and shutdown.
    Under CAA section 112(i)(3), for existing sources subject to the 
AMF, APR and PC MACT standards, the proposed compliance date for PRD 
monitoring 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, or by routing releases to a control device. This 
time period will allow facilities to research equipment and vendors, 
purchase, install, test and properly operate any necessary equipment by 
the compliance date. For new sources subject to the AMF, APR and PC 
MACT standards, the proposed compliance date for PRD monitoring, along 
with the other SSM-related revisions, is the effective date of the 
final amendments.
    For both new and existing sources subject to the AMF, APR and PC 
MACT standards, the proposed compliance date for the operating and 
pressure release management requirements for PRDs, along with the other 
SSM-related revisions, is the effective date of the final amendments. 
We are proposing these compliance dates because these requirements are 
the same as those contained in 40 CFR part 63, subpart UU, with which 
facilities are already complying as part of the existing MACT 
standards.
    For the one existing source subject to the AMF MACT standards, the 
proposed compliance date for the new solution polymerization spinning 
line requirements is the effective date of the final amendments. We 
believe this facility is already complying with these requirements and 
no additional time to come into compliance is warranted.
    Under CAA section 112(i)(3), for existing sources subject to the 
APR MACT standards, the proposed compliance date for the new MACT 
standards applicable to continuous process vents is 3 years from the 
effective date of the final amendments. This time period will allow 
facilities to purchase, install and test any necessary

[[Page 1716]]

equipment. For existing APR sources subject to the new MACT standards 
applicable to storage vessels, the proposed compliance date is the 
effective date of the final amendments. As we stated previously, our 
analysis indicates that all storage vessels are currently controlled to 
the proposed level of control and no additional time to come into 
compliance is warranted. For new sources subject to the APR MACT 
standards, the proposed compliance date for the revised storage vessel 
requirements is the effective date of the final amendments.
    Under CAA section 112(i)(3), for existing sources subject to the 
AMF and PC MACT standards, the proposed compliance date for the revised 
equipment leak standards is 1 year from the effective date of the final 
amendments. Our data indicate that the one AMF facility and some of the 
PC facilities are currently complying with subpart TT requirements and 
will need time to purchase, install and test any necessary equipment 
and modify their existing LDAR programs. For new sources subject to AMF 
and PC MACT standards, the proposed compliance date for the revised 
equipment leak standards is the effective date of the final amendments.

IX. Summary of Cost, Environmental and Economic Impacts

A. What are the affected sources?

    We anticipate that each facility in these three source categories 
will be affected by these proposed amendments. We estimate there is one 
existing facility subject to the AMF MACT standards, 18 existing 
facilities subject to the APR MACT standards and 4 existing facilities 
subject to the PC MACT standards. We do not know of any new facilities 
that are expected to be constructed in the foreseeable future in any of 
these source categories. Therefore, our impact analysis is focused on 
the existing sources affected by the MACT standards for these three 
source categories.

B. What are the air quality impacts?

1. AMF Source Category
    For equipment leaks, we are proposing to eliminate the option of 
complying with subpart TT and allow facilities to comply with only 
subpart UU, except for connectors in gas and vapor service and in light 
liquid service. We are proposing to retain the option to comply with 
subpart TT or subpart UU for these components. We estimate the HAP 
emission reductions for the one facility in the AMF source category to 
be 0.2 tpy.
    We are proposing an emission rate for spinning lines that use spin 
dope produced from a solution polymerization process equal to the MACT 
floor for this facility, which will not result in any quantifiable 
emission reductions.
    For the proposed revisions to the MACT standards regarding SSM, 
including monitoring of PRDs in organic HAP service, while these 
changes may result in fewer emissions during these periods or less 
frequent periods of startup, shutdown or malfunction, these possible 
emission reductions are difficult to quantify and are not included in 
our assessment of air quality impacts.
    Therefore, the total HAP emission reductions for the proposed 
standards for the AMF source category are 0.2 tpy.
2. APR Source Category
    Two facilities in the APR source category have uncontrolled 
continuous process vents. We are proposing standards that will require 
85 percent control of HAP emissions from these process vents. The 
estimated HAP emission reductions for these two facilities are 20.1 
tpy.
    We are proposing to implement emission standards for storage 
vessels at existing facilities. However, our data indicate that all 
storage vessels subject to the proposed standards are already in 
compliance, and no quantifiable emission reductions are expected.
    For the proposed revisions to the MACT standards regarding SSM, 
including monitoring of PRDs in organic HAP service, while these 
changes may result in fewer emissions during these periods or less 
frequent periods of startup, shutdown or malfunction, these possible 
emission reductions are difficult to quantify and are not included in 
our assessment of air quality impacts.
    Therefore, the total HAP emission reductions for the proposed 
standards for the APR source category are 20.1 tpy.
3. PC Source Category
    For equipment leaks, we are proposing to eliminate the option of 
complying with subpart TT and allow facilities to comply with only 
subpart UU, except for connectors in gas and vapor service and in light 
liquid service. We are proposing to retain the option to comply with 
subpart TT or subpart UU for these components. We estimated the HAP 
emission reductions for the four facilities in the PC source category 
to be 2.1 tpy.
    For the proposed revisions to the MACT standards regarding SSM, 
including installation and operation of monitors on PRDs, while these 
changes may result in fewer emissions during these periods or less 
frequent periods of startup, shutdown or malfunction, these possible 
emission reductions are difficult to quantify and are not included in 
our assessment of air quality impacts.
    Therefore, the total HAP emission reductions for the proposed 
standards for the PC source category are 2.1 tpy.

C. What are the cost impacts?

1. AMF Source Category
    For equipment leaks, we are proposing to eliminate the option of 
complying with subpart TT and allow facilities to comply with only 
subpart UU, except for connectors in gas and vapor service and in light 
liquid service. We are proposing to retain the option to comply with 
subpart TT or subpart UU for these components. We estimated the capital 
costs for the one facility in the AMF source category to be $1,400 and 
the annualized costs to be $220.
    We are proposing an emission rate for spinning lines that use spin 
dope produced from a solution polymerization process equal to the MACT 
floor for this facility. Thus, we do not expect any quantifiable 
capital or annual costs for this proposed standard.
    For the proposed requirements to install and operate monitors on 
PRDs, we estimate the capital costs to be $37,000 and the annualized 
costs to be $5,300.
    Therefore, the total capital costs for the AMF source category are 
approximately $38,000, and the total annualized costs are approximately 
$6,000.
2. APR Source Category
    Two facilities in the APR source category have uncontrolled 
continuous process vents. We are proposing standards that will require 
85 percent control of HAP emissions from these process vents. The 
estimated capital costs for these two facilities are $1.1 million and 
the annualized costs are $340,000.
    We are proposing to implement emission standards for storage 
vessels at existing facilities. However, our data indicate that all 
storage vessels subject to the proposed standards are already in 
compliance, and no capital or annual costs are expected.
    For the proposed requirements to install and operate monitors on 
PRDs, we estimate the capital costs to be $400,000 and the annualized 
costs to be $56,000.
    Therefore, the total capital costs for the APR source category are

[[Page 1717]]

approximately $1.5 million, and the total annualized costs are 
approximately $400,000.
3. PC Source Category
    For equipment leaks, we are proposing to eliminate the option of 
complying with subpart TT and allow facilities to comply with only 
subpart UU, except for connectors in gas and vapor service and in light 
liquid service. We are proposing to retain the option to comply with 
subpart TT or subpart UU for these components. We estimated the capital 
costs to be $16,000 and the annualized costs to be $2,200.
    For the proposed requirements to install and operate monitors on 
PRDs, we estimate the capital costs to be $51,000 and the annualized 
costs to be $7,200.
    Therefore, the total capital costs for the PC source category are 
approximately $67,000, and the total annualized costs are approximately 
$9,400.

D. What are the economic impacts?

    We estimate that there will be no more than a 0.5 percent price 
change and a similar reduction in output associated with the proposal. 
This is based on the costs of the rule and responsiveness of producers 
and consumers based on supply and demand elasticities for the 
industries affected by this proposal. The impacts to affected firms 
will be low because the annual compliance costs are quite small when 
compared to the annual revenues for the affected parent firms (much 
less than 1 percent for each). The impacts to affected consumers should 
also be quite small. Thus, there will not be any significant impacts on 
affected firms and their consumers as a result of this proposal.

E. What are the benefits?

    Because this rulemaking is not likely to have an annual effect on 
the economy of $100 million or more, we have not conducted a regulatory 
impact analysis or a benefits analysis. However, the estimated 
reductions in HAP emissions that will be achieved by this proposed rule 
will provide benefits to public health. The proposed standards will 
result in significant reductions in the actual and allowable emissions 
of HAP and will reduce the actual and potential cancer risks and non-
cancer health effects due to emissions of HAP from these source 
categories. We have not quantified the monetary benefits associated 
with these reductions.

X. Request for Comments

    We solicit comments on all aspects of this proposed action. In 
addition to general comments on this proposed action, we are also 
interested in additional data that may 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 XI 
of this preamble provides more information on submitting data.

XI. Submitting Data Corrections

    The site-specific emissions profiles used in the source category 
risk and demographic analyses and instructions are available 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 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, etc.).
    4. Send the entire downloaded file with suggested revisions in 
Microsoft[supreg] Access format and all accompanying documentation to 
Docket ID Number EPA-HQ-OAR-2012-0133 (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.

XII. 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 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) documents 
prepared by the EPA for these rules have been assigned EPA ICR number 
1871.07 (AMF and PC MACT standards) and 1869.08 (APR MACT standards).
    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.
    To provide the public with an estimate of the relative magnitude of 
the burden associated with an assertion of the affirmative defense 
position adopted by a source, the EPA has provided administrative 
adjustments to this ICR to show what the notification, recordkeeping 
and reporting requirements associated with the assertion of the 
affirmative defense might entail. The EPA's estimate for the required 
notification, reports and records for any individual incident, 
including the root cause analysis, totals $2,375 annually per MACT 
standard and is based on the time and effort required of a source to 
review relevant data, interview plant employees and document the events 
surrounding a malfunction that has caused a violation

[[Page 1718]]

of an emissions limit. The estimate also includes time to produce and 
retain the record and reports for submission to the EPA. The EPA 
provides this illustrative estimate of this burden because these costs 
are only incurred if there has been a violation and a source chooses to 
take advantage of the affirmative defense.
    Given the variety of circumstances under which malfunctions could 
occur, as well as differences among sources' operation and maintenance 
practices, we cannot reliably predict the severity and frequency of 
malfunction-related excess emissions events for a particular source. It 
is important to note that the EPA has no basis currently for estimating 
the number of malfunctions that would qualify for an affirmative 
defense. Current historical records would be an inappropriate basis, as 
source owners or operators previously operated their facilities in 
recognition that they were exempt from the requirement to comply with 
emissions standards during malfunctions. Of the number of excess 
emissions events reported by source operators, only a small number 
would be expected to result from a malfunction (based on the definition 
above), and only a subset of excess emissions caused by malfunctions 
would result in the source choosing to assert the affirmative defense. 
Thus, we believe the number of instances in which source operators 
might be expected to avail themselves of the affirmative defense will 
be extremely small. We expect to gather information on such events in 
the future and will revise this estimate as better information becomes 
available.
1. Acrylic and Modacrylic Fibers Production MACT Standards
    The ICR document prepared by the EPA for the amendments to the AMF 
MACT standards we are proposing today has been assigned EPA ICR number 
1871.07. Burden changes associated with these proposed amendments would 
result from new recordkeeping and reporting requirements associated 
with requirements for spinning lines that use spin dope produced from a 
solution polymerization process, the PRD monitoring requirements and 
affirmative defense provisions for all facilities subject to the AMF 
MACT standards.
    We estimate 1 regulated facility is currently subject to the AMF 
requirements in subpart YY. The annual monitoring, reporting and 
recordkeeping burden for this collection (averaged over the first 3 
years after the effective date of the standards) for these amendments 
to subpart YY is estimated to be 54 labor hours at a cost of $3,000 per 
year. There is no estimated change in annual burden to the federal 
government for these amendments.
2. Amino/Phenolic Resins Production MACT Standards
    The ICR document prepared by the EPA for the amendments to the APR 
MACT standards we are proposing today has been assigned EPA ICR number 
1869.08. Burden changes associated with these proposed amendments would 
result from new recordkeeping and reporting requirements associated 
with the PRD monitoring requirements and affirmative defense provisions 
for all facilities subject to the APR MACT standards. In addition, we 
estimate that two facilities will be subject to recordkeeping, 
reporting and monitoring requirements associated with the control of 
certain continuous process vents.
    We estimate 18 regulated facilities are currently subject to 
subpart OOO. The annual monitoring, reporting and recordkeeping burden 
for this collection (averaged over the first 3 years after the 
effective date of the standards) for these amendments to subpart OOO is 
estimated to be 1,178 labor hours at a cost of $66,500 per year. There 
is no estimated change in annual burden to the federal government for 
these amendments.
3. Polycarbonate Production MACT Standards
    The ICR document prepared by the EPA for the amendments to the PC 
MACT standards we are proposing today has been assigned EPA ICR number 
1871.07. Burden changes associated with these proposed amendments would 
result from new recordkeeping and reporting requirements associated 
with the PRD monitoring requirements and affirmative defense provisions 
for all facilities subject to the MACT standards.
    We estimate 4 regulated facilities are currently subject to the PC 
requirements in subpart YY. The annual monitoring, reporting and 
recordkeeping burden for this collection (averaged over the first 3 
years after the effective date of the standards) for these amendments 
to subpart YY is estimated to be 216 labor hours at a cost of $12,000 
per year. There is no estimated change in annual burden to the federal 
government for these amendments.
    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 number EPA-HQ-
OAR-2012-0133. Submit any comments related to the ICR to the EPA and 
OMB. See the ADDRESSES section at the beginning of this proposed rule 
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 EPA. Since OMB is required to make a decision concerning the 
ICR between 30 and 60 days after January 9, 2014, a comment to OMB is 
best assured of having its full effect if OMB receives it by February 
10, 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 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. According to the SBA small business 
standards definitions, for the APR source category, which has the NAICS 
code of 325211 (i.e., Plastics Material and Resin Manufacturing), the 
SBA small business size standard is 750 employees. For the PC source 
category, which has the NAICS code of 325211 (i.e., Plastics Material 
and Resin Manufacturing), the SBA small business size standard is 750 
employees. For the AMF source category, which has the

[[Page 1719]]

NAICS code of 325222 (i.e., Noncellulosic Organic Fiber Manufacturing), 
the SBA small business size standard is 1,000 employees.
    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. This 
proposed rule will not impose any requirements on small entities. There 
are no affected small businesses in the APR, AMF and PC source 
categories. All of the companies affected by this rule are generally 
large integrated corporations that are not considered to be small 
entities per the definitions provided in this section.
    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 the private sector in any one year. The 
total annualized cost of this rule is estimated to be no more than 
$420,000 in any one year. Thus, this proposed rule is not subject to 
the requirements of sections 202 or 205 of the UMRA.
    This 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 proposed rule does not have federalism implications. It will 
not have substantial direct effects on the states, on the relationship 
between the national government and the states, or on the distribution 
of power and responsibilities among the various levels of government, 
as specified in Executive Order 13132. This action will not impose 
substantial direct compliance costs on state or local governments, nor 
will it preempt state law, and none of the facilities subject to this 
action are owned or operated by state or local governments. Thus, 
Executive Order 13132 does not apply to this proposed rule.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between 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 proposed rule does not have tribal implications, as specified 
in Executive Order 13175 (65 FR 67249, November 9, 2000). There are no 
AMF, PC or APR facilities owned or operated by Indian tribal 
governments. Thus, Executive Order 13175 does not apply to this action.
    The EPA specifically solicits additional 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 EPA does not believe the 
environmental health or safety risks addressed by this action present a 
disproportionate risk to children. This action increases the level of 
environmental protection for all affected populations and would not 
cause increases in emissions or emissions-related health risks. The 
EPA's risk assessments (included in the docket for this proposed rule) 
demonstrate that the existing regulations are associated with an 
acceptable level of risk and provide an ample margin of safety to 
protect public health and prevent adverse environmental effects.
    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 AMF, PC or APR production 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, 12(d) (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 rulemaking does not involve new technical standards. 
Therefore the EPA did not consider the use of any VCS.

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 practicable 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 categories and near 
source populations, the EPA conducted a proximity analysis of the 
facilities in the APR and PC source categories 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 categories' risk can be found in sections V and VI of this 
preamble. The complete demographic analysis results and the details 
concerning their development are presented in the memorandum entitled 
Environmental Justice Review: Amino/Phenolic Resins, Acrylic and 
Modacrylic Fibers Production, and Polycarbonate Production, available 
in the docket for

[[Page 1720]]

this action (Docket ID No. EPA-HQ-OAR-2012-0133).
    For the APR source category, the proximity analysis revealed that 
``African American'' and ``Below the Poverty Line'' demographic 
categories are above 20 percent of their corresponding national 
averages. The ratio of African Americans living within 3 miles of any 
source affected by this rule is 62 percent higher than the national 
average (21 percent versus 13 percent) and the ratio of people living 
below the poverty line living within 3 miles of any source affected by 
this rule is 43 percent higher than the national average (20 percent 
versus 14 percent). However, as noted previously, risks from this 
source category were found to be acceptable for all populations.
    For the PC source category, the proximity analysis revealed that 
several demographic categories are above 20 percent of their 
corresponding national averages, including ``Other or Multiracial,'' 
``Hispanic,'' ``Age 0-4,'' ``Age 0-17,'' and ``No High School 
Diploma.'' Within 3 miles of any source affected by this rule, the 
ratio of Other or Multiracial people living is 21 percent higher than 
the national average (17 percent versus 14 percent), the ratio of 
Hispanic people is 135 percent higher than the national average (40 
percent versus 17 percent), the ratio of people aged 0-4 is 29 percent 
higher than the national average (9 percent versus 7 percent), the 
ratio of people aged 0-17 is 25 percent higher than the national 
average (30 percent versus 24 percent), and the ratio of people with no 
high school diploma is 40 percent higher than the national average (14 
percent versus 10 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.

List of Subjects for 40 CFR Part 63

    Environmental protection, Administrative practice and procedures, 
Air pollution control, Hazardous substances, Intergovernmental 
relations, Reporting and recordkeeping requirements.

    Dated: December 11, 2013.
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--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS 
FOR SOURCE CATEGORIES

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

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

Subpart YY--National Emission Standards for Hazardous Air 
Pollutants for Source Categories: Generic Maximum Achievable 
Control Technology Standards

0
2. Section 63.1100 is amended by:
0
a. Revising the last sentence of paragraph (d) introductory text; and
0
b. Adding paragraph (h).
    The revisions and additions read as follows:

Sec.  63.1100  Applicability.

* * * * *
    (d) * * * Paragraphs (d)(3), (4), and (5) of this section discuss 
compliance for those process units operated as flexible operation 
units.
* * * * *
    (h) Affirmative defense for violation of emission standards during 
malfunction. In response to an action to enforce the standards set 
forth in this subpart, the owner or operator of an acrylic and 
modacrylic fiber production affected source or polycarbonate production 
affected source may assert an affirmative defense to a claim for civil 
penalties for violations of such standards that are caused by 
malfunction, as defined at 40 CFR 63.2. Appropriate penalties may be 
assessed if the owner or operator fails to meet their burden of proving 
all of the requirements in the affirmative defense. The affirmative 
defense shall not be available for claims for injunctive relief.
    (1) Assertion of affirmative defense. To establish the affirmative 
defense in any action to enforce such a standard, the owner or operator 
must timely meet the reporting requirements in paragraph (h)(2) of this 
section, and must prove by a preponderance of evidence that:
    (i) The violation:
    (A) Was caused by a sudden, infrequent, and unavoidable failure of 
air pollution control equipment, process equipment, or a process to 
operate in a normal or usual manner; and
    (B) Could not have been prevented through careful planning, proper 
design or better operation and maintenance practices; and
    (C) Did not stem from any activity or event that could have been 
foreseen and avoided, or planned for; and
    (D) Was not part of a recurring pattern indicative of inadequate 
design, operation, or maintenance; and
    (ii) Repairs were made as expeditiously as possible when a 
violation occurred; and
    (iii) The frequency, amount, and duration of the violation 
(including any bypass) were minimized to the maximum extent 
practicable; and
    (iv) If the violation resulted from a bypass of control equipment 
or a process, then the bypass was unavoidable to prevent loss of life, 
personal injury, or severe property damage; and
    (v) All possible steps were taken to minimize the impact of the 
violation on ambient air quality, the environment, and human health; 
and
    (vi) All emissions monitoring and control systems were kept in 
operation if at all possible, consistent with safety and good air 
pollution control practices; and
    (vii) All of the actions in response to the violation were 
documented by properly signed, contemporaneous operating logs; and
    (viii) At all times, the affected source was operated in a manner 
consistent with good practices for minimizing emissions; and
    (ix) A written root cause analysis has been prepared, the purpose 
of which is to determine, correct, and eliminate the primary causes of 
the malfunction and the violation resulting from the malfunction event 
at issue. The analysis shall also specify, using best monitoring 
methods and engineering judgment, the amount of any emissions that were 
the result of the malfunction.
    (2) Report. The owner or operator seeking to assert an affirmative 
defense shall submit a written report to the Administrator, with all 
necessary supporting documentation, that explains how it has met the 
requirements set forth in paragraph (h)(1) of this section. This 
affirmative defense report shall be included in the first periodic 
compliance report, deviation report, or excess emission report 
otherwise required after the initial occurrence of the violation of the 
relevant standard (which may be the end of any applicable averaging 
period). If such compliance report, deviation report, or excess 
emission report is due less than 45 days after the initial occurrence 
of the violation, the affirmative defense report may be included in the 
second compliance report, deviation report, or excess emission report 
due after the initial occurrence of the violation of the relevant 
standard.
0
3. Section 63.1101 is amended by adding in alphabetical order the terms 
``Affirmative defense,'' ``Pressure

[[Page 1721]]

release,'' and ``Pressure relief device or valve'' to read as follows:

Sec.  63.1101  Definitions.

    Affirmative defense means, in the context of an enforcement 
proceeding, a response or defense put forward by a defendant, regarding 
which the defendant has the burden of proof, and the merits of which 
are independently and objectively evaluated in a judicial or 
administrative proceeding.
* * * * *
    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 due to a malfunction in the process.
    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.
* * * * *
0
4. Section 63.1102 is amended by:
0
a. Revising the first sentence of paragraph (a) introductory text; and
0
b. Adding paragraph (b).
    The revisions and additions read as follows:

Sec.  63.1102  Compliance schedule.

    (a) * * * Affected sources, as defined in Sec.  63.1103(a)(1)(i) 
for acetyl resins production, Sec.  63.1103(b)(1)(i) for acrylic and 
modacrylic fiber production, Sec.  63.1103(c)(1)(i) for hydrogen 
fluoride production, Sec.  63.1103(d)(1)(i) for polycarbonate 
production, Sec.  63.1103(e)(1)(i) for ethylene production, Sec.  
63.1103(f)(1)(i) for carbon black production, Sec.  63.1103(g)(1)(i) 
for cyanide chemicals manufacturing, or Sec.  63.1103(h)(1)(i) for 
spandex production shall comply with the appropriate provisions of this 
subpart and the subparts referenced by this subpart according to the 
schedule in paragraph (a)(1) or (2) of this section, as appropriate, 
except as provided in paragraph (b) of this section. * * *
* * * * *
    (b) All acrylic and modacrylic fiber production affected sources 
and polycarbonate production affected sources that commenced 
construction or reconstruction on or before January 9, 2014, shall be 
in compliance with the pressure relief device monitoring requirements 
of Sec.  63.1107(e)(3) upon initial startup or 3 years after the 
effective date of the final amendments, whichever is later, and the 
equipment leaks requirements of 40 CFR part 63, subpart UU upon initial 
startup or 1 year after the effective date of the final amendments, 
whichever is later. New acrylic and modacrylic fiber production 
affected sources and polycarbonate production affected sources that 
commence construction or reconstruction after January 9, 2014, shall be 
in compliance with the pressure relief device monitoring requirements 
of Sec.  63.1107(e)(3) upon initial startup or by the effective date of 
the final amendments, whichever is later.
* * * * *
0
5. Section 63.1103 is amended by:
0
a. Revising paragraph (b)(1)(ii);
0
b. In paragraph (b)(2), adding in alphabetical order the term ``Seal'';
0
c. In paragraph (b)(3)(i), under Table 2, revising entries 4, 5, 6, and 
7 and adding entry 11;
0
d. In paragraph (b)(3)(ii), under Table 3, revising entry 3 and adding 
entry 4;
0
e. Revising paragraph (d)(1)(ii);
0
f. In paragraph (d)(2), adding in alphabetical order the term ``Seal''; 
and
0
g. In paragraph (d)(3), under Table 5, revising entry 6 and adding 
entry 10, and under Table 6, revising entry 5 and adding entry 6.
    The revisions and additions read as follows:

Sec.  63.1103  Source category-specific applicability, definitions, and 
requirements.

* * * * *
    (b) * * *
    (1) * * *
    (ii) Compliance schedule. The compliance schedule, for affected 
sources as defined in paragraph (b)(1)(i) of this section, is specified 
in Sec.  63.1102.
    (2) Definitions.
* * * * *
    Seal means, for the purpose of complying with the requirements of 
Sec.  63.1033(b), that instrument monitoring of the open-ended valve or 
line conducted according to the method specified in Sec.  63.1023(b) 
and, as applicable, Sec.  63.1023(c), indicates no readings of 500 
parts per million or greater.
* * * * *
    (3) * * *
    (i) * * *

Table 2 to Sec.   63.1103(b)(3)(i)--What Are My Requirements If I Own or Operate an Acrylic and Modacrylic Fiber
      Production Existing or New Affected Source and Am Complying With Paragraph (b)(3)(i) of This Section?
----------------------------------------------------------------------------------------------------------------
       If you own or operate . . .                And if . . .                    Then you must . . .
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
4. A fiber spinning line that is a new    The lines use a spin dope    a. Reduce acrylonitrile emissions by 85
 or reconstructed source.                  produced from either a       weight-percent or more. (For example,
                                           suspension polymerization    you may enclose the spinning and washing
                                           process or solution          areas of the spinning line (as specified
                                           polymerization process.      in paragraph (b)(4) of this section) and
                                                                        vent through a closed vent system and
                                                                        use any combination of control devices
                                                                        meeting the requirements of subpart SS,
                                                                        as specified in Sec.   63.982(a), of
                                                                        this part.); or
                                                                       b. Reduce acrylonitrile emissions from
                                                                        the spinning line to less than or equal
                                                                        to 0.25 kilograms of acrylonitrile per
                                                                        megagram (0.5 pounds of acrylonitrile
                                                                        per ton) of acrylic and modacrylic fiber
                                                                        produced; or
                                                                       c. Reduce the acrylonitrile concentration
                                                                        of the spin dope to less than 100 ppmw.
5. A fiber spinning line that is an       The spinning line uses a     Reduce organic HAP emissions from the
 existing source.                          spin dope produced from a    spinning line to less than or equal to
                                           solution polymerization      20 kilograms of organic HAP per megagram
                                           process.                     (40 pounds of organic HAP per ton) of
                                                                        acrylic and modacrylic fiber produced.
6. A fiber spinning line that is an       The spinning line uses a     a. Reduce the acrylonitrile concentration
 existing source.                          spin dope produced from a    of the spin dope to less than 100 ppmw
                                           suspension polymerization    \b\; or
                                           process.

[[Page 1722]]

 
                                                                       b. Reduce acrylonitrile emissions from
                                                                        the spinning line to less than or equal
                                                                        to 0.25 kilograms of acrylonitrile per
                                                                        megagram of acrylic and modacrylic fiber
                                                                        produced.
7. Equipment as defined under Sec.        It contains or contacts      For connectors in gas and vapor service
 63.1101 (with the differences for         >=10 weight-percent          and in light liquid service, comply with
 pressure relief devices described in      acrylonitrile,\c\ and        either Sec.   63.1008 of subpart TT
 item 11 below).                           operates >=300 hours per     (national emission standards for
                                           year.                        equipment leaks (control level 1)) of
                                                                        this part, or Sec.   63.1027 of subpart
                                                                        UU (national emission standards for
                                                                        equipment leaks (control level 2)) of
                                                                        this part. For all other applicable
                                                                        equipment, comply with the requirements
                                                                        of subpart UU of this part, except Sec.
                                                                         63.1030.
 
                                                  * * * * * * *
11. Pressure relief devices.............  The pressure relief device   Comply with Sec.   63.1107(e).
                                           is in organic HAP service.
----------------------------------------------------------------------------------------------------------------

* * * * *
    (ii) * * *

 Table 3 to Sec.   63.1103(b)(3)(ii)--What Are My Requirements If I Own
  or Operate an Acrylic and Modacrylic Fiber Production Existing or New
   Affected Source and Am Complying With Paragraph (b)(3)(ii) of This
                                Section?
------------------------------------------------------------------------
                                           Then you must control total
      If you own or operate . . .         organic HAP emissions from the
                                             affected source by . . .
------------------------------------------------------------------------
 
                              * * * * * * *
3. Equipment as defined under Sec.       For connectors in gas and vapor
 63.1101 and it contains or contacts      service and in light liquid
 >10 weight-percent acrylonitrile,\a\     service, comply with either
 and operates >300 hours per year (with   Sec.   63.1008 of subpart TT
 the differences for pressure relief      (national emission standards
 devices described in item 4 below).      for equipment leaks (control
                                          level 1)) of this part, or
                                          Sec.   63.1027 of subpart UU
                                          (national emission standards
                                          for equipment leaks (control
                                          level 2)) of this part. For
                                          all other applicable
                                          equipment, comply with subpart
                                          UU of this part, except Sec.
                                          63.1030.
4. A pressure relief device in organic   Complying with Sec.
 HAP service.                             63.1107(e).
------------------------------------------------------------------------

* * * * *
    (d) * * *
    (1) * * *
    (ii) Compliance schedule. The compliance schedule, for affected 
sources as defined in paragraph (d)(1)(i) of this section, is specified 
in Sec.  63.1102.
    (2) * * *
    Seal means, for the purpose of complying with the requirements of 
Sec.  63.1033(b), that instrument monitoring of the open-ended valve or 
line conducted according to the method specified in Sec.  63.1023(b) 
and, as applicable, Sec.  63.1023(c), indicates no readings of 500 
parts per million or greater.
* * * * *

 Table 5 to Sec.   63.1103(d)--What Are My Requirements If I Own or Operate a Polycarbonate Production Existing
                                                Affected Source?
----------------------------------------------------------------------------------------------------------------
       If you own or operate . . .                And if . . .                    Then you must . . .
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
6. Equipment as defined under Sec.        The equipment contains or    For connectors in gas and vapor service
 63.1101 (with the differences for         contacts >=5 weight-         and in light liquid service, comply with
 pressure relief devices described in      percent total organic        either Sec.   63.1008 of subpart TT
 item 10 below).                           HAP,\e\ and operates >=300   (national emission standards for
                                           hours per year.              equipment leaks (control level 1)) of
                                                                        this part, or Sec.   63.1027 of subpart
                                                                        UU (national emission standards for
                                                                        equipment leaks (control level 2)) of
                                                                        this part. For all other applicable
                                                                        equipment, comply with the requirements
                                                                        of subpart UU of this part, except Sec.
                                                                         63.1030.
 
                                                  * * * * * * *
10. Pressure relief devices.............  The pressure relief device   Comply with Sec.   63.1107(e).
                                           is in organic HAP service.
----------------------------------------------------------------------------------------------------------------

* * * * *

[[Page 1723]]

    Table 6 to Sec.   63.1103(d)--What Are My Requirements If I Own or Operate a Polycarbonate Production New
                                                Affected Source?
----------------------------------------------------------------------------------------------------------------
       If you own or operate . . .                And if . . .                    Then you must . . .
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
5. Equipment as defined under Sec.        The equipment contains or    For connectors in gas and vapor service
 63.1101 (with the differences for         contacts >=5 weight-         and in light liquid service, comply with
 pressure relief devices described in      percent total organic        either Sec.   63.1008 of subpart TT
 item 6 below).                            HAP,\e\ and operates >=300   (national emission standards for
                                           hours per year.              equipment leaks (control level 1)) of
                                                                        this part, or Sec.   63.1027 of subpart
                                                                        UU ((national emission standards for
                                                                        equipment leaks (control level 2)) of
                                                                        this part. For all other applicable
                                                                        equipment, comply with the requirements
                                                                        of subpart UU of this part, except Sec.
                                                                         63.1030.
6. Pressure relief devices..............  The pressure relief device   Comply with Sec.   63.1107(e).
                                           is in organic HAP service.
----------------------------------------------------------------------------------------------------------------

* * * * *
0
6. Section 63.1104 is amended by revising paragraph (c) to read as 
follows:

Sec.  63.1104  Process vents from continuous unit operations: 
applicability assessment procedures and methods.

* * * * *
    (c) Applicability assessment requirement. The TOC or organic HAP 
concentrations, process vent volumetric flow rates, process vent 
heating values, process vent TOC or organic HAP emission rates, 
halogenated process vent determinations, process vent TRE index values, 
and engineering assessments for process vent control applicability 
assessment requirements are to be determined during maximum 
representative operating conditions for the process, except as provided 
in paragraph (d) of this section, or unless the Administrator specifies 
or approves alternate operating conditions. For acrylic and modacrylic 
fiber production affected sources and polycarbonate production affected 
sources, operations during periods of malfunction shall not constitute 
representative conditions for the purpose of an applicability test. For 
all other affected sources, operations during periods of startup, 
shutdown, and malfunction shall not constitute representative 
conditions for the purpose of an applicability test.
* * * * *
0
7. Section 63.1107 is amended by:
0
a. Revising the section heading; and
0
b. Adding paragraphs (e), (f) and (g).
    The revisions and additions read as follows:

Sec.  63.1107  Equipment leaks.

* * * * *
    (e) Requirements for pressure relief devices. For acrylic and 
modacrylic fiber production affected sources and polycarbonate 
production affected sources, except as specified in paragraph (e)(4) of 
this section, the owner or operator must comply with the requirements 
specified in paragraphs (e)(1) and (2) of this section for pressure 
relief devices in organic HAP gas or vapor service. Except as specified 
in paragraph (e)(4) of this section, the owner or operator of an 
acrylic and modacrylic fiber production affected source or 
polycarbonate production affected source must also comply with the 
requirements specified in paragraph (e)(3) of this section for all 
pressure relief devices in organic HAP service.
    (1) Operating requirements. Except during a pressure release event, 
operate each pressure relief device in organic HAP 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 
organic HAP gas or vapor service, comply with paragraph (e)(2)(i) or 
(ii) of this section, as applicable.
    (i) If the pressure relief device does not consist of or include a 
rupture disk, conduct instrument monitoring, as detected by Method 21 
of 40 CFR part 60, appendix A, no later than 5 calendar days after the 
pressure relief device returns to organic HAP service following a 
pressure release to verify that the pressure relief device is operating 
with an instrument reading of less than 500 ppm above background. After 
5 calendar days, an instrument reading of 500 ppm above background or 
greater is a violation.
    (ii) If the pressure relief device consists of or includes a 
rupture disk, install a replacement disk as soon as practicable after a 
pressure release, but no later than 5 calendar days after the pressure 
release. The owner or operator must also conduct instrument monitoring, 
as detected by Method 21 of 40 CFR part 60, appendix A, no later than 5 
calendar days after the pressure relief device returns to organic HAP 
service following a pressure release to verify that the pressure relief 
device is operating with an instrument reading of less than 500 ppm 
above background. After 5 calendar days, an instrument reading of 500 
ppm above background or greater is a violation.
    (3) Pressure release management. Except as specified in paragraph 
(e)(4) of this section, the owner or operator must comply with the 
requirements specified in paragraphs (e)(3)(i) and (ii) of this section 
for all pressure relief devices in organic HAP service. Any pressure 
release from such a pressure relief device is a violation.
    (i) The owner or operator must equip each pressure relief device in 
organic HAP service with a device(s) or parameter monitoring system 
that is capable of identifying and recording the time and duration of 
each pressure release and of notifying operators immediately that a 
pressure release is occurring. Examples of these types of devices and 
systems include, but are not limited to, a rupture disk indicator, 
magnetic sensor, motion detector on the pressure relief valve stem, 
flow monitor, or pressure monitor. Regardless of the methodology 
chosen, when the device or monitoring system indicates that a pressure 
release has occurred, it shall be directly enforceable as a release 
from the pressure relief device. If this instrument is capable of 
measuring the concentration of leaks through the pressure relief 
device, then the owner or operator may use this instrument to meet the 
requirements of paragraph (e)(2) of this section.
    (ii) If any pressure relief device in organic HAP service releases 
to atmosphere as a result of a pressure release event, the owner or 
operator must calculate the quantity of organic HAP released during 
each pressure release event and report this quantity as required in 
paragraph (g) of this section. 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 control device or process. 
If a pressure

[[Page 1724]]

relief device in organic HAP service is designed and operated to route 
all pressure releases through a closed vent system to a control device 
or process, the owner or operator is not required to comply with 
paragraphs (e)(1), (2), or (3) (if applicable) of this section. Both 
the closed vent system and control device (if applicable) must meet the 
requirements of Sec.  63.1034 of this part.
    (f) Recordkeeping requirements. For acrylic and modacrylic fiber 
production affected sources and polycarbonate production affected 
sources, for pressure relief devices in organic HAP service, keep 
records of the information specified in paragraphs (f)(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 equip with a closed-vent system 
and control device, under the provisions in paragraph (e)(4) of this 
section.
    (2) A list of identification numbers for pressure relief devices 
subject to the provisions in paragraph (e)(1) of this section.
    (3) A list of identification numbers for pressure relief devices 
equipped with rupture disks, under the provisions in paragraph 
(e)(2)(ii) of this section.
    (4) The dates and results of the monitoring following a pressure 
release for each pressure relief device subject to the provisions in 
paragraph (e)(1) and (2) of this section. The results shall include:
    (i) The background level measured during each compliance test.
    (ii) The maximum instrument reading measured at each piece of 
equipment during each compliance test.
    (5) For pressure relief devices in organic HAP service subject to 
paragraph (e)(3) of this section, 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 total HAP 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.
    (g) Periodic reports. For owners or operators of an acrylic and 
modacrylic fiber production affected source or polycarbonate production 
affected source subject to paragraph (e) of this section, Periodic 
Reports must include the information specified in paragraphs (g)(1) 
through (3) of this section for pressure relief devices in organic HAP 
service.
    (1) For pressure relief devices in organic HAP service subject to 
paragraph (e) of this section, report confirmation that all monitoring 
to show compliance was conducted within the reporting period.
    (2) For pressure relief devices in organic HAP gas or vapor service 
subject to paragraph (e)(2) of this section, report any instrument 
reading of 500 ppm above background or greater, more than 5 days after 
the relief device returns to organic HAP gas or vapor service after a 
pressure release.
    (3) For pressure relief devices in organic HAP service subject to 
paragraph (e)(3) of this section, report 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 total HAP emitted during the 
pressure release and the method used for determining this quantity.
    (iv) The actions taken to prevent this pressure release.
    (v) The measures adopted to prevent future such pressure releases.

0
8. Section 63.1108 is amended by:
0
a. Adding paragraph (a) introductory text;
0
b. Adding paragraph (a)(4);
0
c. Revising the first sentence of paragraph (a)(5);
0
d. Revising the first sentence of paragraph (b)(2) introductory text; 
and
0
e. Revising paragraph (b)(4)(ii).
    The revisions and additions read as follows:

Sec.  63.1108  Compliance with standards and operation and maintenance 
requirements.

    (a) Requirements. The requirements of paragraphs (a)(1), (2), and 
(5) of this section apply to all affected sources except acrylic and 
modacrylic fiber production affected sources and polycarbonate 
production affected sources. The requirements of paragraph (a)(4) of 
this section apply only to acrylic and modacrylic fiber production 
affected sources and polycarbonate production affected sources. The 
requirements of paragraphs (a)(3), (6), and (7) of this section apply 
to all affected sources.
* * * * *
    (4)(i) For acrylic and modacrylic fiber production affected sources 
and polycarbonate production affected sources, the emission limitations 
and established parameter ranges of this part 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. Equipment leak requirements shall apply at 
all times except during periods of non-operation of the affected source 
(or specific portion thereof) in which the lines are drained and 
depressurized resulting in cessation of the emissions to which the 
equipment leak requirements apply.
    (ii) 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.
    (5) During startups, shutdowns, and malfunctions when the emission 
standards of this subpart and the subparts referenced by this subpart 
do not apply pursuant to paragraphs (a)(1) through (3) of this section, 
the owner or operator shall implement, to the extent reasonably 
available, measures to prevent or minimize excess emissions. * * *
* * * * *
    (b) * * *
    (2) Parameter monitoring: Excursions. An excursion is not a 
violation in cases where continuous monitoring is required and the 
excursion does not count toward the number of excused excursions (as 
described in Sec.  63.998(b)(6)(ii)), if the conditions of paragraph 
(b)(2)(i) or (ii) of this section are met, except that the conditions 
of paragraph (b)(2)(i) of this section do not apply for acrylic and 
modacrylic fiber production affected sources and polycarbonate 
production affected sources. * * *
* * * * *
    (4) * * *
    (ii) Performance test. The Administrator may determine compliance 
with emission limitations of this subpart based on, but not limited to, 
the results of performance tests conducted according to the procedures

[[Page 1725]]

specified in Sec.  63.997, unless otherwise specified in this subpart 
or a subpart referenced by this subpart. For acrylic and modacrylic 
fiber production affected sources and polycarbonate production affected 
sources, 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 unless specified by the Administrator or an applicable 
subpart. The owner/operator may not conduct performance tests during 
periods of malfunction. The owner 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.
* * * * *
0
9. Section 63.1110 is amended by:
0
a. Adding a sentence to the end of paragraph (a) introductory text;
0
b. Revising paragraph (a)(7);
0
c. Adding paragraph (a)(9);
0
d. Adding a sentence to the end of paragraph (d)(1) introductory text; 
and
0
e. Adding paragraph (d)(1)(iii).
    The revisions and additions read as follows:

Sec.  63.1110  Reporting requirements.

    (a) * * * Each owner or operator of an acrylic and modacrylic fiber 
production affected source or polycarbonate production affected source 
subject to this subpart shall submit the reports listed in paragraph 
(a)(9) of this section, as applicable.
* * * * *
    (7) Startup, Shutdown, and Malfunction Reports described in Sec.  
63.1111 (except for acrylic and modacrylic fiber production affected 
sources and polycarbonate production affected sources).
* * * * *
    (9) Electronic reporting. Within 60 days after the date of 
completing each performance test (as defined in Sec.  63.2), the owner 
or operator must submit the results of the performance tests, including 
any associated fuel analyses, required by this subpart according to the 
methods specified in paragraph (a)(9)(i) or (ii) of this section.
    (i) For data collected using test methods supported by the EPA-
provided software, the owner or operator shall submit the results of 
the performance test to the EPA by direct computer-to-computer 
electronic transfer via EPA-provided software, unless otherwise 
approved by the Administrator. Owners or operators, who claim that some 
of the information being submitted for performance tests is 
confidential business information (CBI), must submit a complete file 
using EPA-provided software that includes 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 file with the CBI omitted must be submitted to the EPA by direct 
computer-to-computer electronic transfer via EPA-provided software.
    (ii) For any performance test conducted using test methods that are 
not compatible with the EPA-provided software, the owner or operator 
shall submit the results of the performance test to the Administrator 
at the appropriate address listed in Sec.  60.4.
* * * * *
    (d) * * *
    (1) * * * For pressure relief devices subject to the requirements 
of Sec.  63.1107(e)(3), the owner or operator of an acrylic and 
modacrylic fiber production affected source or polycarbonate production 
affected source shall submit the information listed in paragraph 
(d)(1)(iii) of this section in the Notification of Compliance Status 
within 150 days after the first applicable compliance date for pressure 
relief device monitoring.
* * * * *
    (iii) For pressure relief devices in organic HAP 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), and a description of the alarms or other 
methods by which operators will be notified of a pressure release.
* * * * *
0
10. Section 63.1111 is amended by:
0
a. Adding paragraph (a) introductory text;
0
b. Adding paragraph (b) introductory text;
0
c. Removing reserved paragraph (b)(3); and
0
d. Adding paragraph (c).
    The revisions and additions read as follows:

Sec.  63.1111  Startup, shutdown, and malfunction.

    (a) Startup, shutdown, and malfunction plan. The requirements of 
this paragraph (a) apply to all affected sources except for acrylic and 
modacrylic fiber production affected sources and polycarbonate 
production affected sources.
* * * * *
    (b) Startup, shutdown, and malfunction reporting requirements. The 
requirements of the paragraph (b) apply to all affected sources except 
for acrylic and modacrylic fiber production affected sources and 
polycarbonate production affected sources.
* * * * *
    (c) Malfunction recordkeeping and reporting. The requirements of 
this paragraph (c) apply only to acrylic and modacrylic fiber 
production affected sources and polycarbonate production affected 
sources.
    (1) Records of malfunctions. The owner or operator shall keep the 
records specified in paragraphs (c)(1)(i) through (iii) of this 
section.
    (i) 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 each failure.
    (ii) 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.
    (iii) Record actions taken to minimize emissions in accordance with 
Sec.  63.1108(a)(4)(ii), and any corrective actions taken to return the 
affected unit to its normal or usual manner of operation.
    (2) 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.

Subpart OOO--National Emission Standards for Hazardous Air 
Pollutant Emissions: Manufacture of Amino/Phenolic Resins

0
11. Section 63.1400 is amended by:
0
a. Revising paragraph (k); and
0
b. Adding paragraph (l).

[[Page 1726]]

    The revisions and additions read as follows:

Sec.  63.1400  Applicability and designation of affected sources.

* * * * *
    (k) 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 emission limitations set forth in 40 CFR part 63, subpart 
UU, as referred to in Sec.  63.1410, shall apply at all times except 
during periods of non-operation of the affected source (or specific 
portion thereof) in which the lines are drained and depressurized 
resulting in cessation of the emissions to which Sec.  63.1410 applies.
    (3) 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.
    (4) 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.
    (l) Affirmative defense for violation of emission standards during 
malfunction. In response to an action to enforce the standards set 
forth in this subpart, the owner or operator may assert an affirmative 
defense to a claim for civil penalties for violations of such standards 
that are caused by malfunction, as defined at 40 CFR 63.2. Appropriate 
penalties may be assessed if the owner or operator fails to meet their 
burden of proving all of the requirements in the affirmative defense. 
The affirmative defense shall not be available for claims for 
injunctive relief.
    (1) Assertion of affirmative defense. To establish the affirmative 
defense in any action to enforce such a standard, the owner or operator 
must timely meet the reporting requirements in paragraph (l)(2) of this 
section, and must prove by a preponderance of evidence that:
    (i) The violation:
    (A) Was caused by a sudden, infrequent, and unavoidable failure of 
air pollution control equipment, process equipment, or a process to 
operate in a normal or usual manner; and
    (B) Could not have been prevented through careful planning, proper 
design or better operation and maintenance practices; and
    (C) Did not stem from any activity or event that could have been 
foreseen and avoided, or planned for; and
    (D) Was not part of a recurring pattern indicative of inadequate 
design, operation, or maintenance; and
    (ii) Repairs were made as expeditiously as possible when a 
violation occurred; and
    (iii) The frequency, amount, and duration of the violation 
(including any bypass) were minimized to the maximum extent 
practicable; and
    (iv) If the violation resulted from a bypass of control equipment 
or a process, then the bypass was unavoidable to prevent loss of life, 
personal injury, or severe property damage; and
    (v) All possible steps were taken to minimize the impact of the 
violation on ambient air quality, the environment, and human health; 
and
    (vi) All emissions monitoring and control systems were kept in 
operation if at all possible, consistent with safety and good air 
pollution control practices; and
    (vii) All of the actions in response to the violation were 
documented by properly signed, contemporaneous operating logs; and
    (viii) At all times, the affected source was operated in a manner 
consistent with good practices for minimizing emissions; and
    (ix) A written root cause analysis has been prepared, the purpose 
of which is to determine, correct, and eliminate the primary causes of 
the malfunction and the violation resulting from the malfunction event 
at issue. The analysis shall also specify, using best monitoring 
methods and engineering judgment, the amount of any emissions that were 
the result of the malfunction.
    (2) Report. The owner or operator seeking to assert an affirmative 
defense shall submit a written report to the Administrator, with all 
necessary supporting documentation, that explains how it has met the 
requirements set forth in paragraph (l)(1) of this section. This 
affirmative defense report shall be included in the first periodic 
compliance report, deviation report, or excess emission report 
otherwise required after the initial occurrence of the violation of the 
relevant standard (which may be the end of any applicable averaging 
period). If such compliance report, deviation report, or excess 
emission report is due less than 45 days after the initial occurrence 
of the violation, the affirmative defense report may be included in the 
second compliance report, deviation report, or excess emission report 
due after the initial occurrence of the violation of the relevant 
standard.
0
12. Section 63.1401 is amended by revising paragraphs (a) and (b) to 
read as follows:

Sec.  63.1401  Compliance schedule.

    (a) New affected sources that commence construction or 
reconstruction after December 14, 1998, shall be in compliance with 
this subpart (except Sec.  63.1411(c)) upon initial start-up or January 
20, 2000, whichever is later. New affected sources that commenced 
construction or reconstruction after December 14, 1998, but on or 
before January 9, 2014, shall be in compliance with the pressure relief 
device monitoring requirements of Sec.  63.1411(c) by 3 years after the 
effective date of the final amendments. New affected sources that 
commence construction or reconstruction after January 9, 2014, shall be 
in compliance with the pressure relief device monitoring requirements 
of Sec.  63.1411(c) upon initial startup or by the effective date of 
the final amendments, whichever is later.
    (b) Existing affected sources shall be in compliance with this 
subpart (except Sec. Sec.  63.1404, 63.1405, and 63.1411(c)) no later 
than 3 years after January 20, 2000. Existing affected sources shall be 
in compliance with the storage vessel requirements of Sec.  63.1404 by 
the effective date of the final amendments. Existing affected sources 
shall be in compliance with the continuous process vent requirements of 
Sec.  63.1405 and the pressure relief device monitoring requirements of 
Sec.  63.1411(c) by 3 years after the effective date of the final 
amendments.
* * * * *
0
13. Section 63.1402 is amended by:
0
a. In paragraph (a), adding in alphabetical order the terms ``Pressure 
release (Sec.  63.161)'' and ``Pressure relief device or valve (Sec.  
63.161)'' and

[[Page 1727]]

removing the term ``Start-up, shutdown, and malfunction plan (Sec.  
63.101)'';
0
b. In paragraph (b), adding in alphabetical order the terms 
``Affirmative defense'' and ``Seal''.
    The revisions and additions read as follows:

Sec.  63.1402  Definitions.

* * * * *
    (b) * * *
    Affirmative defense means, in the context of an enforcement 
proceeding, a response or defense put forward by a defendant, regarding 
which the defendant has the burden of proof, and the merits of which 
are independently and objectively evaluated in a judicial or 
administrative proceeding.
* * * * *
    Seal means, for the purpose of complying with the requirements of 
Sec.  63.1033(b), that instrument monitoring of the open-ended valve or 
line conducted according to the method specified in Sec.  63.1023(b) 
and, as applicable, Sec.  63.1023(c), indicates no readings of 500 
parts per million or greater.
* * * * *
0
14. Section 63.1404 is amended by revising the first sentence of 
paragraph (a) introductory text to read as follows:

Sec.  63.1404  Storage vessel provisions.

    (a) Emission standards. For each storage vessel located at a new or 
existing affected source that has a capacity of greater than or equal 
to 20,000 gallons, but less than 40,000 gallons, and vapor pressure of 
1.9 pounds per square inch absolute (psia) or greater; has a capacity 
of greater than or equal to 40,000 gallons, but less than 90,000 
gallons, and vapor pressure of 0.75 psia or greater; or has a capacity 
of 90,000 gallons or greater and vapor pressure of 0.15 psia or 
greater, the owner or operator shall comply with either paragraph 
(a)(1) or (2) of this section. * * *
* * * * *
0
15. Section 63.1405 is amended by revising the first sentence of 
paragraph (a) introductory text to read as follows:

Sec.  63.1405  Continuous process vent provisions.

    (a) Emission standards. For each continuous process vent located at 
a new or existing affected source with a Total Resource Effectiveness 
(TRE) index value, as determined following the procedures specified in 
Sec.  63.1412(j), less than or equal to 1.2, the owner or operator 
shall comply with either paragraph (a)(1) or (2) of this section. * * *
* * * * *
0
16. Section 63.1410 is amended by revising the first sentence of the 
introductory text to read as follows:

Sec.  63.1410  Equipment leak provisions.

    The owner or operator of each affected source shall comply with the 
requirements of 40 CFR part 63, subpart UU (national emission standards 
for equipment leaks (control level 2)) for all equipment, as defined 
under Sec.  63.1402, that contains or contacts 5 weight-percent HAP or 
greater and operates 300 hours per year or more, except Sec.  63.1030. 
* * *
0
17. Add Sec.  63.1411 to read as follows:

Sec.  63.1411  Requirements for pressure relief devices.

    Except as specified in paragraph (d) of this section, the owner or 
operator must comply with the requirements specified in paragraphs (a) 
and (b) of this section for pressure relief devices in organic HAP gas 
or vapor service. Except as specified in paragraph (d) of this section, 
the owner or operator must also comply with the requirements specified 
in paragraph (c) of this section for all pressure relief devices in 
organic HAP service.
    (a) Operating requirements. Except during a pressure release event, 
operate each pressure relief device in organic HAP 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.
    (b) Pressure release requirements. For pressure relief devices in 
organic HAP gas or vapor service, comply with paragraph (b)(1) or (2) 
of this section, as applicable.
    (1) If the pressure relief device does not consist of or include a 
rupture disk, conduct instrument monitoring, as detected by Method 21 
of 40 CFR part 60, appendix A, no later than 5 calendar days after the 
pressure relief device returns to organic HAP service following a 
pressure release to verify that the pressure relief device is operating 
with an instrument reading of less than 500 ppm above background. After 
5 calendar days, an instrument reading of 500 ppm above background or 
greater is a violation.
    (2) If the pressure relief device consists of or includes a rupture 
disk, install a replacement disk as soon as practicable after a 
pressure release, but no later than 5 calendar days after the pressure 
release. The owner or operator must also conduct instrument monitoring, 
as detected by Method 21 of 40 CFR part 60, appendix A, no later than 5 
calendar days after the pressure relief device returns to organic HAP 
service following a pressure release to verify that the pressure relief 
device is operating with an instrument reading of less than 500 ppm 
above background. After 5 calendar days, an instrument reading of 500 
ppm above background or greater is a violation.
    (c) Pressure release management. Except as specified in paragraph 
(d) of this section, the owner or operator must comply with the 
requirements specified in paragraphs (c)(1) and (2) of this section for 
all pressure relief devices in organic HAP service. Any pressure 
release from such a pressure relief device is a violation.
    (1) The owner or operator must equip each pressure relief device in 
organic HAP service with a device(s) or parameter monitoring system 
that is capable of identifying and recording the time and duration of 
each pressure release and of notifying operators immediately that a 
pressure release is occurring. The device or monitoring system may be 
either specific to the pressure relief device itself or on an 
associated process system or piping sufficient to indicate a pressure 
release to the atmosphere. Examples of these types of devices and 
systems include, but are not limited to, a rupture disk indicator, 
magnetic sensor, motion detector on the pressure relief valve stem, 
flow monitor, or pressure monitor. Regardless of the methodology 
chosen, when the device or monitoring system indicates that a pressure 
release has occurred, it shall be directly enforceable as a release 
from the pressure relief device. If this instrument is capable of 
measuring the concentration of leaks through the pressure relief 
device, then the owner or operator may use this instrument to meet the 
requirements of paragraph (b) of this section.
    (2) If any pressure relief device in organic HAP service releases 
to atmosphere as a result of a pressure release event, the owner or 
operator must calculate the quantity of organic HAP released during 
each pressure release event and report this quantity as required in 
Sec.  63.1417(f)(13)(iii). Calculations may be based on data from the 
pressure relief device monitoring alone or in combination with process 
parameter monitoring data and process knowledge.
    (d) Pressure relief devices routed to a control device or process. 
If a pressure relief device in organic HAP service is designed and 
operated to route all pressure releases through a closed vent system to 
a control device or process, the owner or operator is not required to 
comply with paragraphs (a), (b), or (c) (if applicable) of this 
section. Both the closed vent system and control device

[[Page 1728]]

(if applicable) must meet the requirements of Sec.  63.1034 of this 
part.
0
18. Section 63.1412 is amended by revising the last sentence of 
paragraph (c) to read as follows:

Sec.  63.1412  Continuous process vent applicability assessment 
procedures and methods.

* * * * *
    (c) Applicability assessment requirement. * * * Operations during 
periods of malfunction shall not constitute representative conditions 
for the purpose of an applicability test.
* * * * *
0
19. Section 63.1413 is amended by:
0
a. Revising paragraph (a)(2) introductory text;
0
b. Revising paragraph (h)(4) introductory text; and
0
c. Revising paragraphs (h)(5) and (h)(6).
    The revisions and additions read as follows:

Sec.  63.1413  Compliance demonstration procedures.

    (a) * * *
    (2) Performance tests. 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 and in accordance with the General Provisions at 
Sec.  63.7(a)(1), (a)(3), (d), (e)(2), (e)(4), (g), and (h), with the 
exceptions specified in paragraph (a)(1) of this section. 
Representative conditions exclude periods of startup and shutdown 
unless specified by the Administrator or an applicable subpart. The 
owner/operator may not conduct performance tests during periods of 
malfunction. The owner 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. Data shall be reduced in 
accordance with the EPA approved methods specified in this subpart or, 
if other test methods are used, the data and methods shall be validated 
according to the protocol in Method 301 of appendix A of this part.
* * * * *
    (h) * * *
    (4) Deviation from the emission standard. If monitoring data are 
insufficient, as described in paragraphs (h)(4)(i) through (iii) of 
this section, there has been a deviation from the emission standard.
* * * * *
    (5) Situations that are not deviations. If any of the situations 
listed in paragraphs (h)(5)(i) or (ii) of this section occur, such 
situations shall not be considered to be deviations.
    (i) Monitoring data cannot be collected during monitoring device 
calibration check or monitoring device malfunction; or
    (ii) Monitoring data are not collected during periods of 
nonoperation of the affected source or portion thereof (resulting in 
cessation of the emissions to which the monitoring applies).
    (6) Periods not considered to be part of the period of control or 
recovery device operation. The periods listed in paragraphs (h)(6)(i) 
and (ii) of this section are not considered to be part of the period of 
control or recovery device operation for purposes of determining 
averages or periods of control device or control technology operation.
    (i) Monitoring system breakdowns, repairs, calibration checks, and 
zero (low-level) and high-level adjustments; or
    (ii) Periods of nonoperation of the affected source (or portion 
thereof), resulting in cessation of the emissions to which the 
monitoring applies.
0
20. Section 63.1415 is amended by revising the second sentence of 
paragraph (b)(1)(ii)(C) to read as follows:

Sec.  63.1415  Monitoring requirements.

* * * * *
    (b) * * *
    (1) * * *
    (ii) * * *
    (C) * * * The plan shall require determination of gas stream flow 
by a method which will at least provide a value for either a 
representative or the highest gas stream flow anticipated in the 
scrubber during representative operating conditions other than 
malfunctions. * * *
0
21. Section 63.1416 is amended by:
0
a. Revising paragraphs (b) and (c)(4);
0
b. Adding paragraph (g)(5);
0
c. Revising the first sentence of paragraph (h)(1)(i);
0
d. Revising paragraph (h)(1)(ii);
0
e. Revising the first sentence of paragraph (h)(1)(iii);
0
f. Revising the last sentence of paragraph (h)(2)(iii); and
0
g. Revising paragraph (h)(2)(iv).
    The revisions and additions read as follows:

Sec.  63.1416  Recordkeeping requirements.

* * * * *
    (b) Malfunction records. Records shall be kept as specified in 
paragraphs (b)(1) and (2) 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 each 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.  63.1420(h)(4), and any corrective actions taken to return the 
affected unit to its normal or usual manner of operation.
    (c) * * *
    (4) Monitoring data recorded during periods identified in 
paragraphs (c)(4)(i) and (ii) of this section shall not be included in 
any average computed under this subpart. Records shall be kept of the 
times and durations of all such periods and any other periods during 
process or control device or recovery device or control technology 
operation when monitors are not operating:
    (i) Monitoring system breakdowns, repairs, calibration checks, and 
zero (low-level) and high-level adjustments; and
    (ii) Periods of non-operation of the affected source (or portion 
thereof) resulting in cessation of the emissions to which the 
monitoring applies.
* * * * *
    (g) * * *
    (5) For pressure relief devices in organic HAP service, keep 
records of the information specified in paragraphs (g)(5)(i) through 
(v) of this section, as applicable.
    (i) A list of identification numbers for pressure relief devices 
that the owner or operator elects to equip with a closed-vent system 
and control device, under the provisions in Sec.  63.1411(d).
    (ii) A list of identification numbers for pressure relief devices 
subject to the provisions in Sec.  63.1411(a).
    (iii) A list of identification numbers for pressure relief devices 
equipped with rupture disks, under the provisions in Sec.  
63.1411(b)(2).
    (iv) The dates and results of the monitoring following a pressure 
release for each pressure relief device subject to the provisions in 
Sec.  63.1411(a) and (b). The results shall include:
    (A) The background level measured during each compliance test.
    (B) The maximum instrument reading measured at each piece of 
equipment during each compliance test.
    (v) For pressure relief devices in organic HAP service subject to

[[Page 1729]]

Sec.  63.1411(c), keep records of 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 total HAP emitted during the 
pressure release and the calculations used for determining this 
quantity.
    (D) The actions taken to prevent this pressure release.
    (E) The measures adopted to prevent future such pressure releases.
    (h) * * *
    (1) * * *
    (i) The monitoring system is capable of detecting unrealistic or 
impossible data during periods of operation (e.g., a temperature 
reading of -200 [deg]C on a boiler) and will alert the operator by 
alarm or other means. * * *
    (ii) The monitoring system generates, updated at least hourly 
throughout each operating day, a running average of the parameter 
values that have been obtained during that operating day or block, and 
the capability to observe this running average is readily available on-
site to the Administrator during the operating day. The owner or 
operator shall record the occurrence of any period meeting the criteria 
in paragraphs (h)(1)(ii)(A) and (B) of this section. All instances in 
an operating day or block constitute a single occurrence:
    (A) The running average is above the maximum or below the minimum 
established limits; and
    (B) The running average is based on at least six 1-hour average 
values.
    (iii) The monitoring system is capable of detecting unchanging data 
during periods of operation, except in circumstances where the presence 
of unchanging data is the expected operating condition based on past 
experience (e.g., pH in some scrubbers) and will alert the operator by 
alarm or other means. * * *
* * * * *
    (2) * * *
    (iii) * * * For any calendar week, if compliance with paragraphs 
(h)(1)(i) through (iv) of this section does not result in retention of 
a record of at least one occurrence or measured parameter value, the 
owner or operator shall record and retain at least one value during a 
period of operation.
    (iv) For purposes of paragraph (h)(2) of this section, a deviation 
means that the daily average, batch cycle daily average, or block 
average value of monitoring data for a parameter is greater than the 
maximum, or less than the minimum established value.
0
22. Section 63.1417 is amended by:
0
a. Revising the first sentence of paragraph (d);
0
b. Removing and reserving paragraph (d)(9);
0
c. Revising paragraph (d)(11)(ii);
0
d. Revising paragraph (e) introductory text;
0
e. Adding paragraph (e)(10);
0
f. Revising the first sentence of paragraph (f)(1);
0
g. Adding paragraph (f)(13);
0
h. Revising paragraph (g);
0
i. Revising paragraph (h) introductory text; and
0
j. Adding paragraph (h)(8).
    The revisions and additions read as follows:

Sec.  63.1417  Reporting requirements.

* * * * *
    (d) Precompliance Report. Owners or operators of affected sources 
requesting an extension for compliance; requesting approval to use 
alternative monitoring parameters, alternative continuous monitoring 
and recordkeeping, or alternative controls; requesting approval to use 
engineering assessment to estimate organic HAP emissions from a batch 
emissions episode as described in Sec.  63.1414(d)(6)(i)(C); wishing to 
establish parameter monitoring levels according to the procedures 
contained in Sec.  63.1413(a)(4)(ii); establishing parameter monitoring 
levels based on a design evaluation as specified in Sec.  
63.1413(a)(3); or following the procedures in Sec.  63.1413(e)(2), 
shall submit a Precompliance Report according to the schedule described 
in paragraph (d)(1) of this section. * * *
* * * * *
    (11) * * *
    (ii) Supplements to the Precompliance Report may be submitted to 
request approval to use alternative monitoring parameters, as specified 
in paragraph (j) of this section; to use alternative continuous 
monitoring and recordkeeping, as specified in paragraph (k) of this 
section; to use alternative controls, as specified in paragraph (d)(5) 
of this section; to use engineering assessment to estimate organic HAP 
emissions from a batch emissions episode, as specified in paragraph 
(d)(6) of this section; or to establish parameter monitoring levels 
according to the procedures contained in Sec.  63.1413(a)(4)(ii) or 
(a)(3), as specified in paragraph (d)(7) of this section.
    (e) Notification of Compliance Status. For existing and new 
affected sources, a Notification of Compliance Status shall be 
submitted within 150 days after the compliance dates specified in Sec.  
63.1401. For equipment leaks, the Notification of Compliance Status 
shall contain the information specified in 40 CFR part 63, subpart UU. 
For storage vessels, continuous process vents, batch process vents, and 
aggregate batch vent streams, the Notification of Compliance Status 
shall contain the information listed in paragraphs (e)(1) through (9) 
of this section. For pressure relief devices subject to the 
requirements of Sec.  63.1411(c), the owner or operator shall submit 
the information listed in paragraph (e)(10) of this section in the 
Notification of Compliance Status within 150 days after the first 
applicable compliance date for pressure relief device monitoring.
* * * * *
    (10) For pressure relief devices in organic HAP 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), and a description of the alarms or other 
methods by which operators will be notified of a pressure release.
    (f) * * *
    (1) Except as specified in paragraph (f)(12) of this section, a 
report containing the information in paragraph (f)(2) of this section 
or containing the information in paragraphs (f)(3) through (11) and 
(13) of this section, as appropriate, shall be submitted semiannually 
no later than 60 days after the end of each 180 day period. * * *
* * * * *
    (13) For pressure relief devices, Periodic Reports must include the 
information specified in paragraphs (f)(13)(i) through (iii) of this 
section.
    (i) For pressure relief devices in organic HAP service subject to 
Sec.  63.1411, report confirmation that all monitoring to show 
compliance was conducted within the reporting period.
    (ii) For pressure relief devices in organic HAP gas or vapor 
service subject to Sec.  63.1411(b), report any instrument reading of 
500 ppm above background or greater, more than 5 days after the relief 
device returns to organic HAP gas or vapor service after a pressure 
release.
    (iii) For pressure relief devices in organic HAP service subject to 
Sec.  63.1411(c), 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 total HAP emitted during the 
pressure release and the method used for determining this quantity.
    (D) The actions taken to prevent this pressure release.

[[Page 1730]]

    (E) The measures adopted to prevent future such pressure releases.
    (g) 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.
    (h) Other reports. Other reports shall be submitted as specified in 
paragraphs (h)(1) through (8) of this section.
* * * * *
    (8) Electronic reporting. Within 60 days after the date of 
completing each performance test (as defined in Sec.  63.2), the owner 
or operator must submit the results of the performance tests, including 
any associated fuel analyses, required by this subpart according to the 
methods specified in paragraph (h)(8)(i) or (ii) of this section.
    (i) For data collected using test methods supported by the EPA-
provided software, the owner or operator shall submit the results of 
the performance test to the EPA by direct computer-to-computer 
electronic transfer via EPA-provided software, unless otherwise 
approved by the Administrator. Owners or operators, who claim that some 
of the information being submitted for performance tests is 
confidential business information (CBI), must submit a complete file 
using EPA-provided software that includes 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 file with the CBI omitted must be submitted to the EPA by direct 
computer-to-computer electronic transfer via EPA-provided software.
    (ii) For any performance test conducted using test methods that are 
not compatible with the EPA-provided software, the owner or operator 
shall submit the results of the performance test to the Administrator 
at the appropriate address listed in Sec.  60.4.
* * * * *
0
23. Table 1 to subpart OOO is amended by:
0
a. Removing entries 63.1(a)(6)-63.1 (a)(8) and 63.1(a)(9);
0
b. Adding entries 63.1(a)(6) and 63.1(a)(7)-63.1(a)(9);
0
c. Revising entries 63.1(c)(4), 63.6(e), 63.6(e)(1)(i), and 
63.6(e)(1)(ii);
0
d. Adding entry 63.6(e)(3);
0
e. Removing entries 63.6(e)(3)(i), 63.6(e)(3)(i)(A), 63.6(e)(3)(i)(B), 
63.6(e)(3)(i)(C), 63.6(e)(3)(ii), 63.6(e)(3)(iii), 63.6(e)(3)(iv), 
63.6(e)(3)(v), 63.6(e)(3)(vi), 63.6(e)(3)(vii), 63.6(e)(3)(vii)(A), 
63.6(e)(3)(vii)(B), 63.6(e)(3)(vii)(C), 63.6(e)(3)(viii), and 
63.6(e)(3)(ix);
0
f. Revising entries 63.6(f)(1), 63.7(e)(1), 63.8(c)(1)(i), 
63.8(c)(1)(ii), 63.8(c)(1)(iii), and 63.10(d)(5); and
0
g. Removing footnote (a).
    The revisions and additions read as follows:

     Table 1 to Subpart OOO of Part 63--Applicability of General Provisions to Subpart OOO Affected Sources
----------------------------------------------------------------------------------------------------------------
                Reference                         Applies to subpart OOO                   Explanation
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
63.1(a)(6)..............................  Yes..................................  ...............................
63.1(a)(7)-63.1(a)(9)...................  No...................................  [Reserved].
 
                                                  * * * * * * *
63.1(c)(4)..............................  No...................................  [Reserved].
 
                                                  * * * * * * *
63.6(e).................................  Yes..................................  Except as otherwise specified
                                                                                  in this table.
63.6(e)(1)(i)...........................  No...................................  See Sec.   63.1400(k)(4) for
                                                                                  general duty requirement.
63.6(e)(1)(ii)..........................  No...................................  ...............................
 
                                                  * * * * * * *
63.6(e)(3)..............................  No...................................  ...............................
63.6(f)(1)..............................  No...................................  ...............................
 
                                                  * * * * * * *
63.7(e)(1)..............................  No...................................  See Sec.   63.1413(a)(2).
 
                                                  * * * * * * *
63.8(c)(1)(i)...........................  No...................................  ...............................
63.8(c)(1)(ii)..........................  No...................................  ...............................
63.8(c)(1)(iii).........................  No...................................  ...............................
 
                                                  * * * * * * *
63.10(d)(5).............................  No...................................  See Sec.   63.1417(g) for
                                                                                  malfunction reporting
                                                                                  requirements.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

0
24. Table 5 to subpart OOO is amended by:
0
a. Removing entry 63.1417(g); and
0
b. Adding entry 63.1417(h)(8).
    The revisions and additions read as follows:

[[Page 1731]]

   Table 5 to Subpart OOO of Part 63--Reports Required by This Subpart
------------------------------------------------------------------------
                                  Description of
           Reference                  report              Due date
------------------------------------------------------------------------
 
                              * * * * * * *
63.1417(h)(8).................  Electronic         Within 60 days after
                                 reporting.         completing
                                                    performance test.
------------------------------------------------------------------------

* * * * *
[FR Doc. 2013-30132 Filed 1-8-14; 8:45 am]
BILLING CODE 6560-50-P
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