Document ID: EPA-HQ-OAR-2016-0490-0001
Agency: epa
Document Type: Proposed Rule
Title: National Emission Standards for Hazardous Air Pollutants: Publicly Owned Treatment Works
Posted Date: 2016-12-27T05:00Z

[Federal Register Volume 81, Number 248 (Tuesday, December 27, 2016)]
[Proposed Rules]
[Pages 95352-95396]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-30471]

[[Page 95351]]

Vol. 81

Tuesday,

No. 248

December 27, 2016

Part III

Environmental Protection Agency

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40 CFR Part 63

National Emission Standards for Hazardous Air Pollutants: Publicly 
Owned Treatment Works; Proposed Rule

  Federal Register / Vol. 81 , No. 248 / Tuesday, December 27, 2016 / 
Proposed Rules  

[[Page 95352]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2016-0490; FRL-9956-87-OAR]
RIN 2060-AS85

National Emission Standards for Hazardous Air Pollutants: 
Publicly Owned Treatment Works

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing 
amendments to the National Emission Standards for Hazardous Air 
Pollutants (NESHAP) for Publicly Owned Treatment Works (POTW) to 
address the results of the residual risk and technology review (RTR) 
conducted under the Clean Air Act (CAA). As a result of our review, we 
are proposing to include pretreatment requirements to limit emissions 
from collection systems and the POTW treatment plant; requirements for 
existing, new, or reconstructed industrial (Group 1) POTW to comply 
with both the requirements in this rule and those in the applicable 
NESHAP for which they act as control; and hazardous air pollutants 
(HAP) emission limits for existing, non-industrial (Group 2) POTW. In 
addition, the EPA is proposing to revise the applicability criteria, 
revise the names and definitions of the industrial (Group 1) and non-
industrial (Group 2) subcategories, revise regulatory provisions 
pertaining to emissions during periods of startup, shutdown, and 
malfunction, add requirements for electronic reporting, and make other 
miscellaneous edits and technical corrections.

DATES: Comments. Comments must be received on or before February 27, 
2017. Under the Paperwork Reduction Act (PRA), comments on the 
information collection provisions are best assured of consideration if 
the Office of Management and Budget (OMB) receives a copy of your 
comments on or before January 26, 2017.
    Public Hearing. A public hearing will be held on January 11, 2017, 
if requested by January 3, 2017.

ADDRESSES: Comments. Submit your comments, identified by Docket ID No. 
EPA-HQ-OAR-2016-0490, at http://www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from http://www.regulations.gov. The EPA may 
publish any comment received to its public docket. Do not submit 
electronically any information you consider to be Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Multimedia submissions (audio, video, etc.) must be 
accompanied by a written comment. The written comment is considered the 
official comment and should include discussion of all points you wish 
to make. The EPA will generally not consider comments or comment 
contents located outside of the primary submission (i.e., on the Web, 
cloud, or other file sharing system). For additional submission 
methods, the full EPA public comment policy, information about CBI or 
multimedia submissions, and general guidance on making effective 
comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Karen Marsh, Sector Policies and Programs Division 
(E143-05), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-1065; fax number: (919) 541-3470; 
and email address: marsh.karen@epa.gov. For specific information 
regarding the risk modeling methodology, contact Michael Stewart, 
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) 
541-7524; fax number: (919) 541-0237; and email address: 
stewart.michael@epa.gov. For information about the applicability of the 
NESHAP to a particular entity, contact Patrick Yellin, Office of 
Enforcement and Compliance Assurance, U.S. Environmental Protection 
Agency, EPA WJC South Building, Mail Code 2227A, 1200 Pennsylvania 
Avenue NW., Washington DC 20460; telephone number: (202) 564-2970; fax 
number: (202) 564-0050; and email address: yellin.patrick@epa.gov.

SUPPLEMENTARY INFORMATION:
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2016-0490. 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, Room 3334, EPA WJC West Building, 
1301 Constitution Avenue 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.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2016-0490. 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 CBI or other information whose disclosure is restricted by 
statute. Do not submit information that you consider to be CBI or 
otherwise protected through http://www.regulations.gov or email. The 
http://www.regulations.gov Web site is an ``anonymous access'' system, 
which means the EPA will not know your identity or contact information 
unless you provide it in the body of your comment. If you send an email 
comment directly to the EPA without going through http://www.regulations.gov, your email address will be automatically captured 
and included as part of the comment that is placed in the public docket 
and made available on the Internet. If you submit an electronic 
comment, the EPA recommends that you include your name and other 
contact information in the body of your comment and with any disk or 
CD-ROM you submit. If the EPA cannot read your comment due to technical 
difficulties and cannot contact you for clarification, the EPA may not 
be able to consider your comment. Electronic files should not include 
special characters or any form of encryption and be free of any defects 
or viruses. For additional information about the EPA's public docket, 
visit the EPA Docket Center homepage at http://www.epa.gov/dockets.
    Public Hearing. A public hearing will be held, if requested by 
January 3, 2017, to accept oral comments on this proposed action. If a 
hearing is requested, it will be held at the EPA's Washington, DC 
campus located at 1201 Constitution Avenue NW., Washington, DC. The 
hearing, if requested, will begin at 9:00 a.m. (local time) and will 
conclude at 4:00 p.m. (local time) on January 11, 2017. To request a 
hearing,

[[Page 95353]]

to register to speak at a hearing, or to inquire if a hearing will be 
held, please contact Aimee St. Clair at (919) 541-1063 or by email at 
stclair.aimee@epa.gov. The last day to pre-register to speak at a 
hearing, if one is held, will be January 9, 2017. 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. Please note that registration requests received 
before the hearing will be confirmed by the EPA via email.
    The EPA will make every effort to accommodate all speakers who 
arrive and register. Because the hearing will be held 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. Please note that the 
REAL ID Act, passed by Congress in 2005, established new requirements 
for entering federal facilities. If your driver's license is issued by 
Alaska, American Samoa, Arizona, Kentucky, Louisiana, Maine, 
Massachusetts, Minnesota, Montana, New York, Oklahoma or the state of 
Washington, you must present an additional form of identification to 
enter the federal building. Acceptable alternative forms of 
identification include: Federal employee badges, passports, enhanced 
driver's licenses and military identification cards. 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.
    Please note that any updates made to any aspect of the hearing, 
including whether or not a hearing will be held, will be posted online 
at https://www.epa.gov/stationary-sources-air-pollution/publicly-owned-treatment-works-potw-national-emission-standards. We ask that you 
contact Aimee St. Clair at (919) 541-1063 or by email at 
stclair.aimee@epa.gov or monitor our Web site to determine if a hearing 
will be held. The EPA does not intend to publish a notice in the 
Federal Register announcing any such updates. Please go to https://www.epa.gov/stationary-sources-air-pollution/publicly-owned-treatment-works-potw-national-emission-standards for more information on the 
public hearing.
    Preamble Acronyms and Abbreviations. We use multiple acronyms and 
terms in this preamble. While this list may not be exhaustive, to ease 
the reading of this preamble and for reference purposes, the EPA 
defines the following terms and acronyms here:

AEGL Acute exposure guideline levels
AERMOD Air dispersion model used by the HEM-3 model
ATSDR Agency for Toxic Substances and Disease Registry
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
CWA Clean Water Act
ECHO Enforcement and Compliance History Online
EJ Environmental justice
EPA Environmental Protection Agency
ERPG Emergency Response Planning Guidelines
ERT Electronic Reporting Tool
FR Federal Register
HAP Hazardous air pollutants
HCl Hydrochloric acid
HEM-3 Human Exposure Model, Version 1.1.0
HF Hydrogen fluoride
HI Hazard index
HQ Hazard quotient
ICR Information collection request
IRIS Integrated Risk Information System
km Kilometer
LAER Lowest achievable emission rate
LOAEL Lowest-observed-adverse-effect level
MACT Maximum achievable control technology
MGD Million gallons per day
mg/kg-day Milligrams per kilogram per day
mg/m\3\ Milligrams per cubic meter
MIR Maximum individual risk
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NAS National Academy of Sciences
NATA National Air Toxics Assessment
NEI National Emissions Inventory
NESHAP National emissions standards for hazardous air pollutants
NOAA National Oceanic and Atmospheric Administration
NOAEL No-observed-adverse-effect levels
NRC National Research Council
NSR New source review
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
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
PEL Probable effect level
POM Polycyclic organic matter
POTW Publicly owned treatment works
ppm Parts per million
PRA Paperwork Reduction Act
RACT Reasonably available control technology
REL Reference exposure level
RFA Regulatory Flexibility Act
RfC Reference concentration
RfD Reference dose
RTR Residual risk and technology review
SAB Science Advisory Board
SOP Standard operating procedure
SSM Startup, shutdown, and malfunction
TOSHI Target organ-specific hazard index
tpy Tons per year
TRIM.FaTE Total Risk Integrated Methodology.Fate, Transport, and 
Ecological Exposure model
UF Uncertainty factor
[mu]g/m\3\ microgram per cubic meter
UMRA Unfunded Mandates Reform Act
URE Unit risk estimate
VCS Voluntary consensus standards

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

I. General Information

A. Does this action apply to me?

    Table 1 of this preamble lists the NESHAP and associated regulated 
industrial source category that is the subject of this proposal. Table 
1 is not intended to be exhaustive, but rather provides a guide for 
readers regarding the entities that this proposed action is likely to 
affect. The proposed standards, once promulgated, will be directly 
applicable to the affected sources. Federal, state, local, and tribal 
governments would be affected as discussed below. By definition, a POTW 
is owned by a municipality, state, intermunicipal or interstate agency, 
or any department, agency, or instrumentality of the federal government 
(See 40 CFR 63.1595 of subpart VVV). If a POTW has a design capacity to 
treat at least 5 million gallons per day (MGD) of wastewater, receives 
wastewater from industrial users, and is either a major source of HAP 
emissions or treats wastewater to comply with requirements of another 
NESHAP, then the POTW is affected by these standards. (Note, these 
applicability criteria represent proposed revisions to the current 
criteria and are discussed further in section IV.D.1 of this document.) 
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 POTW source category includes emissions from 
wastewaters that are treated at a POTW. These wastewaters are generated 
by industrial, commercial, and domestic sources, although only 
industrial and commercial dischargers might consistently discharge HAP 
in quantities high enough to potentially result in an exceedance of the 
major source emission threshold at the POTW. Emissions from these 
wastewaters can

[[Page 95354]]

occur within the collection system (sewers) as well as during treatment 
at the POTW. Control options include, but are not limited to, reduction 
of HAP at the industrial discharger before wastewater enters the 
collection systems, add-on emission controls on the collection system 
and at the POTW, and/or treatment process modifications/substitutions.

    Table 1--NESHAP and Industrial Source Categories Affected by This
                             Proposed Action
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         Source category                  NESHAP          NAICS code \1\
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Sewage Treatment Facilities......  Subpart VVV.........          221320
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\1\ North American Industry Classification System.

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

    In addition to being available in the docket, an electronic copy of 
this action is available on the Internet. A redline 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-2016-0490). Following signature by the EPA Administrator, the 
EPA will post a copy of this proposed action at https://www.epa.gov/stationary-sources-air-pollution/publicly-owned-treatment-works-potw-national-emission-standards. Following publication in the Federal 
Register, the EPA will post the Federal Register version of the 
proposal and key technical documents at this same Web site. Information 
on the overall residual risk and technology review (RTR) program is 
available at http://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.

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

    Submitting CBI. Do not submit information containing CBI to the EPA 
through http://www.regulations.gov or email. Clearly mark the part or 
all of the information that you claim to be CBI. For CBI information on 
a disk or CD-ROM that you mail to the EPA, mark the outside of the disk 
or CD-ROM as CBI and then identify electronically within the disk or 
CD-ROM the specific information that is claimed as CBI. In addition to 
one complete version of the comments that includes information claimed 
as CBI, you must submit a copy of the comments that does not contain 
the information claimed as CBI for inclusion in the public docket. If 
you submit a CD-ROM or disk that does not contain CBI, mark the outside 
of the disk or CD-ROM clearly that it does not contain CBI. Information 
not marked as CBI will be included in the public docket and the EPA's 
electronic public docket without prior notice. Information marked as 
CBI will not be disclosed except in accordance with procedures set 
forth in 40 CFR part 2. Send or deliver information identified as CBI 
only to the following address: OAQPS Document Control Officer (C404-
02), OAQPS, U.S. Environmental Protection Agency, Research Triangle 
Park, North Carolina 27711, Attention Docket ID No. EPA-HQ-OAR-2016-
0490.

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 HAP. For major sources, the technology-based NESHAP must 
reflect the maximum degree of emission reductions of HAP achievable 
(after considering cost, energy requirements, and non-air quality 
health and environmental impacts) and are commonly referred to as 
maximum achievable control technology (MACT) standards.
    MACT standards must reflect the maximum degree of emissions 
reduction achievable through the application of measures, processes, 
methods, systems, or techniques, including, but not limited to, 
measures that (1) Reduce the volume of or eliminate pollutants through 
process changes, substitution of materials or other modifications; (2) 
enclose systems or processes to eliminate emissions; (3) capture or 
treat pollutants when released from a process, stack, storage, or 
fugitive emissions point; (4) are design, equipment, work practice, or 
operational standards (including requirements for operator training or 
certification); or (5) are a combination of the above. CAA section 
112(d)(2)(A)-(E). The MACT standards may take the form of design, 
equipment, work practice, or operational standards where the EPA first 
determines either that (1) a pollutant cannot be emitted through a 
conveyance designed and constructed to emit or capture the pollutant, 
or that any requirement for, or use of, such a conveyance would be 
inconsistent with law; or (2) the application of measurement 
methodology to a particular class of sources is not practicable due to 
technological and economic limitations. CAA section 112(h)(1)-(2).
    The MACT ``floor'' is the minimum control level allowed for MACT 
standards promulgated under CAA section 112(d)(3) and may not be based 
on cost considerations. For new sources, the MACT floor cannot be less 
stringent than the emissions control that is achieved in practice by 
the best-controlled similar source. The MACT floor for existing sources 
can be less stringent than floors for new sources, but not less 
stringent than the average emissions limitation achieved by the best-
performing 12 percent of existing sources in the category or 
subcategory (or the best-performing five sources for categories or 
subcategories with fewer than 30 sources). In developing MACT 
standards, the EPA must also consider control options that are more 
stringent than the floor. We may establish standards more stringent 
than the floor based on considerations of the cost of achieving the 
emission reductions, any non-air quality health and environmental 
impacts, and energy requirements.
    The EPA is 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 8 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.,

[[Page 95355]]

``residual'') risk according to CAA section 112(f). CAA section 
112(f)(1) requires 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. CAA section 112(f)(2) then 
provides that if Congress does not act on any recommendation in the 
Risk Report, the EPA must analyze and address residual risk for each 
category or subcategory of sources 8 years after promulgation of such 
standards pursuant to CAA section 112(d).
    Section 112(f)(2) of the CAA requires the EPA to determine for 
source categories subject to MACT standards whether the emission 
standards provide an ample margin of safety to protect public health. 
Section 112(f)(2)(B) of the CAA expressly preserves the EPA's use of 
the two-step process for developing standards to address any residual 
risk and the Agency's interpretation of ``ample margin of safety'' 
developed in the National Emissions Standards for Hazardous Air 
Pollutants: Benzene Emissions from Maleic Anhydride Plants, 
Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment 
Leaks, and Coke By-Product Recovery Plants (Benzene NESHAP) (54 FR 
38044, September 14, 1989). The EPA notified Congress in the Risk 
Report that the Agency intended to use the Benzene NESHAP approach in 
making CAA section 112(f) residual risk determinations (EPA-453/R-99-
001, p. ES-11). The EPA subsequently adopted this approach in its 
residual risk determinations and in a challenge to the risk review for 
the Synthetic Organic Chemical Manufacturing source category, the 
United States Court of Appeals for the District of Columbia Circuit 
upheld as reasonable the EPA's interpretation that CAA section 
112(f)(2) incorporates the approach established in the Benzene NESHAP. 
See NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008) (``[S]ubsection 
112(f)(2)(B) expressly incorporates the EPA's interpretation of the 
Clean Air Act from the Benzene standard, complete with a citation to 
the Federal Register.''); see also, A Legislative History of the Clean 
Air Act Amendments of 1990, vol. 1, p. 877 (Senate debate on Conference 
Report).
    The first step in the process of evaluating residual risk is the 
determination of acceptable risk. If risks are unacceptable, the EPA 
cannot consider cost in identifying the emissions standards necessary 
to bring risks to an acceptable level. The second step is the 
determination of whether standards must be further revised in order to 
provide an ample margin of safety to protect public health. The ample 
margin of safety is the level at which the standards must be set, 
unless an even more stringent standard is necessary to prevent, taking 
into consideration costs, energy, safety, and other relevant factors, 
an adverse environmental effect.
1. Step 1--Determination of Acceptability
    The Agency in the Benzene NESHAP concluded that ``the acceptability 
of risk under section 112 is best judged on the basis of a broad set of 
health risk measures and information'' and that the ``judgment on 
acceptability cannot be reduced to any single factor.'' Benzene NESHAP 
at 54 FR 38046, September 14, 1989. The determination of what 
represents an ``acceptable'' risk is based on a judgment of ``what 
risks are acceptable in the world in which we live'' (Risk Report at 
178, quoting NRDC v. EPA, 824 F. 2d 1146, 1165 (D.C. Cir. 1987) (en 
banc) (``Vinyl Chloride''), recognizing that our world is not risk-
free.
    In the Benzene NESHAP, we stated that ``EPA will generally presume 
that if the risk to [the maximum exposed] individual is no higher than 
approximately one in 10 thousand, that risk level is considered 
acceptable.'' 54 FR at 38045, September 14, 1989. We discussed the 
maximum individual lifetime cancer risk (or maximum individual risk 
(MIR)) as being ``the estimated risk that a person living near a plant 
would have if he or she were exposed to the maximum pollutant 
concentrations for 70 years.'' Id. We explained that this measure of 
risk ``is an estimate of the upper bound of risk based on conservative 
assumptions, such as continuous exposure for 24 hours per day for 70 
years.'' Id. We acknowledged that maximum individual lifetime cancer 
risk ``does not necessarily reflect the true risk, but displays a 
conservative risk level which is an upper-bound that is unlikely to be 
exceeded.'' Id.
    Understanding that there are both benefits and limitations to using 
the MIR as a metric for determining acceptability, we acknowledged in 
the Benzene NESHAP that ``consideration of maximum individual risk * * 
* must take into account the strengths and weaknesses of this measure 
of risk.'' Id. Consequently, the presumptive risk level of 100-in-1 
million (1-in-10 thousand) provides a benchmark for judging the 
acceptability of maximum individual lifetime cancer risk, but does not 
constitute a rigid line for making that determination. Further, in the 
Benzene NESHAP, we noted that:

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

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

[i]n establishing a presumption for MIR, rather than a rigid line 
for acceptability, the Agency intends to weigh it with a series of 
other health measures and factors. These include the overall 
incidence of cancer or other serious health effects within the 
exposed population, the numbers of persons exposed within each 
individual lifetime risk range and associated incidence within, 
typically, a 50 km exposure radius around facilities, the science 
policy assumptions and 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 CAA section 
112(f)(2) ``incorporates the EPA's interpretation of the Clean Air Act 
from the Benzene Standard.'' The court further held that Congress' 
incorporation of the Benzene standard applies equally to carcinogens 
and non-carcinogens. 529 F.3d at 1081-82. Accordingly, we also consider 
non-cancer risk metrics in our determination of risk acceptability and 
ample margin of safety.
2. Step 2--Determination of Ample Margin of Safety
    CAA section 112(f)(2) requires the EPA to determine, for source 
categories subject to MACT standards, whether those standards provide 
an ample margin of safety to protect public health.

[[Page 95356]]

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, September 14, 1989.
    According to CAA section 112(f)(2)(A), if the MACT standards for 
HAP ``classified as a known, probable, or possible human carcinogen do 
not reduce lifetime excess cancer risks to the individual most exposed 
to emissions from a source in the category or subcategory to less than 
one in one million,'' the EPA must promulgate residual risk standards 
for the source category (or subcategory), as necessary to provide an 
ample margin of safety to protect public health. In doing so, the EPA 
may adopt standards equal to existing MACT standards if the EPA 
determines that the existing standards (i.e., the MACT standards) are 
sufficiently protective. NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 
2008) (``If EPA determines that the existing technology-based standards 
provide an `ample margin of safety,' then the Agency is free to readopt 
those standards during the residual risk rulemaking.'') The EPA must 
also adopt more stringent standards, if necessary, to prevent an 
adverse environmental effect,\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 at 38044-38045, September 14, 1989, we stated as 
an overall objective:

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

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

B. What is this source category and how does the 2002 NESHAP regulate 
its HAP emissions?

1. Definition of the POTW Source Category and the Affected Source
    The NESHAP for the POTW source category (henceforth referred to as 
the ``POTW NESHAP'') was promulgated on October 26, 1999 (64 FR 57572) 
and codified at 40 CFR part 63, subpart VVV. The POTW NESHAP was 
amended on October 21, 2002 (67 FR 64742). As amended in 2002, the POTW 
NESHAP applies to new and existing POTW treatment plants that are 
located at a POTW that is a major source of HAP emissions and that is 
required to develop and implement a pretreatment program as defined by 
40 CFR 403.8 under the Clean Water Act. Emissions from a POTW originate 
from wastewaters that are treated at a POTW. These wastewaters are 
generated by industrial, commercial, and domestic sources, although 
only industrial and commercial dischargers might consistently discharge 
HAP in quantities high enough to potentially result in an exceedance of 
the major source emission threshold at the POTW. Emissions from these 
wastewaters can occur within the collection system (sewers) as well as 
during treatment at the POTW treatment plant. Control options include, 
but are not limited to, reduction of HAP at the source before they 
enter the collection system, add-on emission controls on the collection 
system and at the POTW, and/or treatment process modifications/
substitutions.
    The POTW NESHAP (40 CFR 63.1595) defines ``POTW'' as ``a treatment 
works, as that term is defined by section 112(e)(5) of the Clean Air 
Act, which is owned by a municipality (as defined by section 502(4) of 
the Clean Water Act),\2\ a state, an intermunicipal or interstate 
agency, or any department, agency, or instrumentality of the federal 
government. This definition includes any intercepting sewers, outfall 
sewers, sewage collection systems, pumping, power, and other equipment. 
The wastewater treated by these facilities is generated by industrial, 
commercial, and domestic sources. As used in this regulation, the term 
POTW refers to both any publicly owned treatment works which is owned 
by a state, municipality, or intermunicipal or interstate agency and 
therefore eligible to receive grant assistance under the Subchapter II 
of the Clean Water Act, and any federally owned treatment works as that 
term is described in section 3023 of the Solid Waste Disposal Act.'' 
The ``affected source'' regulated by the 2002 POTW NESHAP is defined in 
40 CFR 63.1595 of the POTW NESHAP as the ``group of all equipment that 
comprise the POTW treatment plant.'' The ``POTW treatment plant'' is 
defined as the ``portion of the POTW which is designed to provide 
treatment (including recycling and reclamation) of municipal sewage and 
industrial waste.'' The 2002 POTW NESHAP excludes collection systems, 
including sewers, pump stations, and other conveyance equipment located 
outside the POTW treatment plant from the definition of affected 
source.
---------------------------------------------------------------------------

    \2\ CAA section 112(e)(5) adopts the definition of ``treatment 
works'' from Clean Water Act (CWA) section 212(2), 33 U.S.C. 
1292(2).
---------------------------------------------------------------------------

2. Applicability of the 2002 NESHAP: Industrial (Group 1) and Non-
Industrial (Group 2) Subcategories
    The 2002 POTW NESHAP set air pollution control requirements or 
emission limits on existing, new, and reconstructed POTW. Briefly, a 
POTW

[[Page 95357]]

is subject to the POTW NESHAP if: (1) The POTW is required to establish 
and implement a pretreatment program per the requirements in 40 CFR 
403.8 under the CWA. Pretreatment programs are required for POTW with a 
design capacity of greater than 5 MGD and that receive wastewater from 
an ``industrial user'' that contains pollutants which pass through or 
interfere with the operation of the POTW. Pollutants that pass through 
are those that remain in the wastewater and are not removed during 
treatment operations at the POTW; and (2) either of the following:
     The POTW accepts waste streams regulated by another NESHAP 
and provides treatment and controls as an agent for the industrial 
facility. The industrial facility complies with its NESHAP requirements 
specific to that wastewater stream by using the treatment and controls 
located at the POTW; or
     The POTW is a major source of HAP emissions.
    Accordingly, POTW that are area sources are not subject to the 
requirements in the 2002 rule unless they receive wastewater that is 
subject to control under another NESHAP.
    Today we estimate that six facilities are subject to the POTW 
NESHAP. A complete list of facilities subject to the POTW NESHAP is 
available in the POTW RTR database, which is available for review in 
the docket for this proposed rulemaking. The EPA recognizes that there 
are approximately 16,000 POTW in the U.S.; however, most of these are 
small municipalities that do not treat wastewater from industrial 
users, and therefore, would not be subject to this regulation. 
Additionally, POTW that do treat wastewater from industrial users are 
generally required to develop and implement a pretreatment program that 
limits the concentration of pollutants in wastewaters received at the 
POTW, thus reducing the potential emissions of HAP so that they are 
below major source thresholds. The EPA requests comment specifically 
identifying other POTW that are subject to the POTW NESHAP.
    In the 2002 NESHAP, the source category is subcategorized based on 
the way in which the POTW is providing treatment for wastewaters 
received from an industrial source. The 2002 POTW NESHAP defines (40 
CFR 63.1595) an ``industrial POTW'' as ``a POTW that accepts a waste 
stream regulated by another NESHAP and provides treatment and controls 
as an agent for the industrial discharger. The industrial discharger 
complies with its NESHAP by using the treatment and controls located at 
the POTW. For example, an industry discharges its benzene-containing 
waste stream to the POTW for treatment to comply with 40 CFR part 61, 
subpart FF--National Emission Standard for Benzene Waste Operations. 
This definition does not include POTW treating waste streams not 
specifically regulated under another NESHAP.'' In other words, if a 
POTW is used as the control method by which an industrial source meets 
the wastewater requirements in their source category NESHAP, then the 
POTW is considered an ``industrial POTW treatment plant.'' An 
``industrial POTW treatment plant'' is affected by the 2002 POTW NESHAP 
regardless of the HAP emissions (i.e., does not have to be a major 
source).
    In contrast, under the 2002 NESHAP, a ``non-industrial POTW'' is 
defined (40 CFR 63.1595) as ``a POTW that does not meet the definition 
of an industrial POTW as defined above.'' If a POTW treats wastewater 
from industrial users, but does not treat industrial wastewaters 
subject to control requirements in another NESHAP, then the POTW is a 
``non-industrial POTW treatment plant.'' See section IV.D.2 of this 
preamble for a discussion on proposed changes to these subcategories, 
including proposed changes to the names for these subcategories (i.e., 
Group 1 and Group 2).
3. HAP Emission Points
    The amount and type of HAP emitted from a POTW is dependent on the 
composition of the wastewater streams discharged to a POTW by 
industrial users. Because HAP are not typically used in large 
quantities by domestic dischargers, we do not expect domestic 
dischargers to consistently or frequently contribute HAP constituents 
to the wastewater and any domestic discharges of HAP are trivial in 
comparison to industrial dischargers. An industrial user is defined in 
the 2002 regulation to include both industrial and commercial 
facilities that discharge wastewaters to the POTW. The primary HAP 
emitted from the POTW that were identified as subject to the 2002 
NESHAP include acetaldehyde, acetonitrile, chloroform, ethylene glycol, 
formaldehyde, methanol, methylene chloride, tetrachloroethylene, 
toluene, and xylenes. HAP present in wastewater entering POTW can 
biodegrade, adhere to sewage sludge, volatilize to the air, or pass 
through (remain in the wastewater discharge) to receiving waters. 
Within the POTW source category, wastewater treatment units are the 
most likely source for HAP emissions, but wastewater collection 
systems, including sewers and other transport systems, may also have 
significant emissions in cases where the systems transport industrial 
wastewater. In addition to the wastewater treatment processes at a 
POTW, other sources of HAP emissions, such as sewage sludge 
incinerators, may be collocated at the same site. Sewage sludge 
incineration is regulated under section 129 of the CAA and is not a 
part of the POTW source category regulated under the POTW NESHAP as 
discussed in this preamble. However, HAP emissions from any collocated 
sources must be included when determining whether a source is a major 
source of HAP.
4. Regulation of HAP Emissions in the 2002 POTW NESHAP
    The POTW NESHAP specifies requirements for both subcategories. 
Under the POTW NESHAP, an existing, industrial (Group 1) POTW must meet 
the requirements of the industrial source's NESHAP. For example, a POTW 
that accepts and treats wastewater for a pulp and paper facility in 
order to meet the wastewater requirements in 40 CFR part 63, subpart S 
is subject to the specific requirements found in subpart S, instead of 
requirements found in 40 CFR part 63, subpart VVV. A new or 
reconstructed, industrial (Group 1) POTW must meet the requirements of 
the industrial source's NESHAP or the requirements for new or 
reconstructed, non-industrial (Group 2) POTW, whichever is more 
stringent.
    There are no control requirements in the 2002 NESHAP for existing, 
non-industrial (Group 2) POTW. However, new or reconstructed, non-
industrial (Group 2) POTW must equip each treatment unit up to, but not 
including, the secondary influent pumping station, with a cover. The 
affected emission points at new or reconstructed non-industrial (Group 
2) POTW include, but are not limited to, influent waste stream 
conveyance channels, bar screens, grit chambers, grinders, pump 
stations, aerated feeder channels, primary clarifiers, primary effluent 
channels, and primary screening stations. In addition, all covered 
units, except the primary clarifiers, must have the air in the 
headspace ducted to a control device in accordance with 40 CFR 63.693, 
the standards for closed-vent systems and control devices found in 
subpart DD of this part. As an alternative to these requirements, a new 
or reconstructed, non-industrial (Group 2) POTW can demonstrate, for 
all units up to the secondary influent pumping station or the secondary 
treatment units, that the HAP fraction emitted does not exceed 0.014. 
This is demonstrated by dividing the sum of all HAP emissions

[[Page 95358]]

from the primary treatment units by the sum of all HAP mass loadings 
(i.e., the concentration of all HAP in the influent wastewater) on an 
annual rolling average. The POTW is allowed to use any combination of 
pretreatment, wastewater treatment plant modifications, and control 
devices to achieve this performance standard.

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

    In October 2015, the EPA issued an information collection request 
(ICR), pursuant to CAA section 114, to nine POTW (covering a total of 
18 facilities) that were known to, or thought to potentially, own and 
operate a POTW subject to the POTW NESHAP. EPA requested information on 
the treatment units that are subject to requirements in the POTW NESHAP 
(primary treatment units), as well as information on pretreatment 
programs, collection sewers, and secondary treatment units. EPA also 
requested information on control devices and location coordinates 
(latitude and longitude) of the individual treatment units (if fugitive 
sources) and emission points (if point sources). The ICR requested 
information on any HAP-containing chemicals used as part of the 
wastewater treatment process, point and fugitive HAP emissions, 
practices used to control HAP emissions, and other aspects of facility 
operations. The respondents to the ICR provided information on a total 
of five facilities subject to the POTW NESHAP and 12 synthetic area \3\ 
or area source facilities not subject to the POTW NESHAP. Only the POTW 
subject to the NESHAP were included in the risk modeling analysis. One 
facility did not provide a response and it is unknown if this POTW is 
subject to the POTW NESHAP. We received emissions data directly from 
each POTW subject to the POTW NESHAP that responded to the survey in 
the form of ToxChem+ or WATER9 modeling results. Following the initial 
response, one POTW that was previously thought to be subject to the 
POTW NESHAP submitted correspondence from their state, which defines 
the POTW as an area source of HAP emissions, therefore, not subject to 
the POTW NESHAP.\4\ Thus, we identified a total of four POTW subject to 
the POTW NESHAP through the 2015 ICR.
---------------------------------------------------------------------------

    \3\ A synthetic area facility installs controls in order to 
reduce HAP emissions below major source thresholds prior to the 
initial compliance date of the NESHAP.
    \4\ See Letter from State of Missouri regarding Bissell Point, 
2016. While the agency no longer considers this POTW to be a major 
source or subject to the POTW NESHAP, the POTW is still included in 
discussions in supporting materials and risk modeling.
---------------------------------------------------------------------------

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

    The 2011 National Emissions Inventory (NEI version 2) provided 
supplemental information for this RTR. The NEI is a database that 
contains information about sources that emit criteria air pollutants, 
their precursors, and HAP. The database includes estimates of annual 
air pollutant emissions from point, nonpoint, and mobile sources in the 
50 states, the District of Columbia, Puerto Rico, and the Virgin 
Islands. The EPA collects this information and releases an updated 
version of the NEI database every 3 years. The NEI includes information 
necessary for conducting risk modeling, including annual HAP emissions 
estimates from individual emission points at facilities and the related 
emissions release parameters.
    For each emission record needed for the model input file for the 
risk assessment (hereafter referred to as the ``RTR emissions 
dataset'') that was not available from the 2015 ICR responses, the EPA 
used available data in the 2011 NEI as the first alternative.\5\ The 
2011 NEI was used to identify an additional two POTW that are subject 
to the POTW NESHAP that had not received the ICR. For the six sources 
found subject to the POTW NESHAP (the four POTW identified in the ICR 
responses and the two POTW identified from the NEI), the 2011 NEI 
provided emissions estimates for co-located emission points that are 
not part of the POTW source category. These data include emissions from 
boilers, engines, and sewage sludge incinerators that are located at 
the POTW, but are not in the POTW source category. These data were 
incorporated into the RTR emissions dataset to determine the whole 
facility risk.
---------------------------------------------------------------------------

    \5\ See Inputs to the Publicly Owned Treatment Works March 2016 
Residual Risk Modeling, June 2016, located in docket number EPA-HQ-
OAR-2016-0490.
---------------------------------------------------------------------------

    The EPA's Enforcement Compliance History Online (ECHO) database was 
also used as a tool to identify which POTW were potentially subject to 
the POTW NESHAP and provided a list of sources to consider for the 2015 
ICR. ECHO provides integrated compliance and enforcement information 
for approximately 800,000 regulated facilities nationwide. Using the 
search feature in ECHO, the EPA identified twenty POTW that could 
potentially be subject to the POTW NESHAP. The EPA then searched state 
Web sites for operating permits for these 20 POTW to determine whether 
the permits stated the POTW was subject to the rule. The four POTW 
identified as subject to the POTW NESHAP through the ICR were 
identified in the list of potential sources found in the ECHO database 
and subsequent permit search.
    The EPA searched for Reasonably Available Control Technology 
(RACT), Best Available Control Technology (BACT), and Lowest Achievable 
Emission Rate (LAER) determinations in the RACT/BACT/LAER 
Clearinghouse. This is a database that contains case-specific 
information of air pollution technologies that have been required to 
reduce the emissions of air pollutants from stationary sources. Under 
the EPA's New Source Review (NSR) program, if a facility is planning 
new construction or a modification that will increase the air emissions 
by a large amount, an NSR permit must be obtained. This central 
database promotes the sharing of information among permitting agencies 
and aids in case-by-case determinations for NSR permits. We examined 
information contained in the RACT/BACT/LAER Clearinghouse to determine 
what technologies are currently used at POTW to reduce air emissions.

III. Analytical Procedures

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

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

    The EPA conducted a risk assessment that provides estimates of the 
MIR posed by the HAP emissions from each source in the source category, 
the hazard index (HI) for chronic exposures to HAP with the potential 
to cause non-cancer health effects, and the hazard quotient (HQ) for 
acute exposures to HAP with the potential to cause non-cancer health 
effects. The assessment also provides estimates of the distribution of 
cancer risks within the exposed populations, cancer incidence, and an 
evaluation of the potential for adverse environmental effects. The 
seven sections that follow this paragraph describe how we estimated 
emissions and conducted the risk assessment. The docket for this 
rulemaking contains the following document which provides more 
information on the risk assessment inputs and models: Residual Risk 
Assessment for the Publicly Owned Treatment Works Source Category in 
Support of the December 2016 Risk and Technology Review Proposed Rule 
(hereafter ``Residual Risk Report''). The

[[Page 95359]]

methods used to assess risks (as described in the seven primary steps 
below) are consistent with the methods that were 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.\6\ The methods used here 
are also consistent with the key recommendations contained in that 
report.
---------------------------------------------------------------------------

    \6\ U.S. EPA SAB. Risk and Technology Review (RTR) Risk 
Assessment Methodologies: For Review by the EPA's Science Advisory 
Board with Case Studies--MACT I Petroleum Refining Sources and 
Portland Cement Manufacturing, May 2010.
---------------------------------------------------------------------------

1. How did we estimate actual emissions and identify the emissions 
release characteristics?
    Data for seven POTW were used to create the RTR emissions dataset, 
as described in section II.C of this preamble. As stated in section 
II.C of this preamble, we evaluated the risk associated with emissions 
from seven POTW, even though one POTW was later determined to be an 
area source of HAP emissions. The emissions sources included in the RTR 
emissions dataset include the following types of emission sources 
currently regulated by the POTW NESHAP: Primary treatment units 
including, lift stations, bar screens, grit chambers, grinders, 
Parshall flumes, denitrification, primary clarifiers, primary settling 
basins, and primary effluent channels. The RTR emissions dataset also 
includes the following types of emission sources not currently 
regulated by the POTW NESHAP: Secondary treatment units, including 
secondary clarifiers, aeration tanks, trickling filters, UNOX systems, 
and open lagoons; tertiary treatment units, including chlorine sumps, 
splitter boxes, and chlorine contact tanks; and gravity thickeners for 
sludge handling. For both emissions sources that are and those that are 
not currently regulated by the POTW NESHAP, the dataset includes both 
fugitive emissions and stack emissions. This RTR emissions dataset is 
based primarily on data gathered through the 2015 ICR and supplemented 
with data from 2011 NEI, 2011 NATA, and ECHO, as described in sections 
II.C and II.D of this preamble. These data sources provided all of the 
emissions data in the RTR emissions dataset and nearly all of the 
facility-specific data needed to conduct the risk modeling analysis. 
However, there were limited instances where default values were used to 
fill gaps in the facility-specific data used in the risk modeling 
analysis. For example, default values were used for stack and fugitive 
release parameters. Use of defaults are discussed in detail in the 
memorandum, Inputs to the Publicly Owned Treatment Works March 2016 
Residual Risk Modeling, June 2016 (Modeling Inputs Memo), available in 
the docket for this action.
    The RTR emissions dataset was refined following an extensive 
quality assurance check of source locations, emission release 
characteristics, and annual emission estimates. We checked the 
coordinates of each emission source in the dataset using ArcGIS to 
ensure the emission point locations were correct. For further 
information on the EPA's quality assurance review, see the Modeling 
Inputs Memo available in the docket for this action.
    A list of the six POTW and additional information used to develop 
the RTR emissions dataset are available in the POTW RTR database 
itself, and additional documentation on the development of this 
database is provided in the Modeling Inputs Memo, both of which are 
available in the docket for this action.
2. How did we estimate MACT-allowable emissions?
    The available emissions data in the RTR emissions dataset include 
estimates of the mass of HAP emitted during the specified annual time 
period. In some cases, these ``actual'' emission levels are lower than 
the emission levels required to comply with the current 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 RTR (70 FR 19998-19999, April 15, 2005) and in the proposed 
and final Hazardous Organic NESHAP RTRs (71 FR 34428, June 14, 2006, 
and 71 FR 76609, December 21, 2006, respectively). In those actions, we 
noted that assessing the risks at the MACT-allowable level is 
inherently reasonable since these risks reflect the maximum level 
facilities could emit and still comply with national emission 
standards. We also explained that it is reasonable to consider actual 
emissions, where such data are available, in both steps of the risk 
analysis, in accordance with the Benzene NESHAP approach. (54 FR 38044, 
September 14, 1989.)
    We used the RTR emissions dataset to estimate MACT-allowable 
emissions levels. POTW were asked to provide their design capacity and 
their average treatment capacity as part of the 2015 ICR. In 
discussions with the POTW that responded, EPA noted that most POTW 
operate below their design capacity. To be conservative, the EPA 
estimated that the reported emissions were for operations at half 
capacity. Therefore, the EPA chose to use a single multiplier of 2.0 to 
scale the actual annual emissions to allowable annual emissions. The 
docket for this rulemaking contains information on the development of 
estimated MACT-allowable emissions in the Modeling Inputs Memo.
3. How did we conduct dispersion modeling, determine inhalation 
exposures, and estimate individual and population inhalation risks?
    Both long-term and short-term inhalation exposure concentrations 
and health risks from the source category addressed in this proposal 
were estimated using the Human Exposure Model (Community and Sector 
HEM-3 version 1.1.0). The HEM-3 performs three primary risk assessment 
activities: (1) Conducting dispersion modeling to estimate the 
concentrations of HAP in ambient air, (2) estimating long-term and 
short-term inhalation exposures to individuals residing within 50 
kilometers (km) of the modeled sources,\7\ and (3) estimating 
individual and population-level inhalation risks using the exposure 
estimates and quantitative dose-response information.
---------------------------------------------------------------------------

    \7\ 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.\8\ To perform the dispersion modeling and to 
develop the preliminary risk estimates, HEM-3 draws on three data 
libraries. The first is a library of meteorological data, which is used 
for dispersion calculations. This library includes 1 year (2011) of 
hourly surface and upper air observations for more than 800 
meteorological stations, selected to provide coverage of the United 
States and Puerto Rico. A second library of United States Census Bureau 
census block \9\ 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

[[Page 95360]]

health benchmarks are the latest values recommended by the EPA for HAP 
and other toxic air pollutants. These values are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants and are discussed in more 
detail later in this section.
---------------------------------------------------------------------------

    \8\ 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).
    \9\ A census block is the smallest geographic area for which 
census statistics are tabulated.
---------------------------------------------------------------------------

    In developing the risk assessment for chronic exposures, we used 
the estimated annual average ambient air concentrations of each HAP 
emitted by each source for which we have emissions data in the source 
category. The air concentrations at each nearby census block centroid 
were used as a surrogate for the chronic inhalation exposure 
concentration for all the people who reside in that census block. We 
calculated the MIR for each facility as the cancer risk associated with 
a continuous lifetime (24 hours per day, 7 days per week, and 52 weeks 
per year for a 70-year period) exposure to the maximum concentration at 
the centroid of inhabited census blocks. Individual cancer risks were 
calculated by multiplying the estimated lifetime exposure to the 
ambient concentration of each of the HAP (in micrograms per cubic meter 
([mu]g/m\3\)) by its unit risk estimate (URE). The URE is an upper 
bound estimate of an individual's probability of contracting cancer 
over a lifetime of exposure to a concentration of 1 microgram of the 
pollutant per cubic meter of air. For residual risk assessments, we 
generally use URE values from the EPA's Integrated Risk Information 
System (IRIS). For carcinogenic pollutants without IRIS values, we look 
to other reputable sources of cancer dose-response values, often using 
California EPA (CalEPA) URE values, where available. In cases where 
new, scientifically credible dose response values have been developed 
in a manner consistent with the EPA guidelines and have undergone a 
peer review process similar to that used by the EPA, we may use such 
dose-response values in place of, or in addition to, other values, if 
appropriate.
    The EPA estimated incremental individual lifetime cancer risks 
associated with emissions from the facilities in the source category as 
the sum of the risks for each of the carcinogenic HAP (including those 
classified as carcinogenic to humans, likely to be carcinogenic to 
humans, and suggestive evidence of carcinogenic potential) \10\ emitted 
by the modeled sources. Cancer incidence and the distribution of 
individual cancer risks for the population within 50 km of the sources 
were also estimated for the source category as part of this assessment 
by summing individual risks. A distance of 50 km is consistent with 
both the analysis supporting the 1989 Benzene NESHAP (54 FR 38044, 
September 14, 1989) and the limitations of Gaussian dispersion models, 
including AERMOD.
---------------------------------------------------------------------------

    \10\ 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) titled NATA--Evaluating 
the National-scale Air Toxics Assessment 1996 Data--an SAB Advisory, 
available at http://yosemite.epa.gov/sab/sabproduct.nsf/
214C6E915BB04E14852570CA007A682C/$File/ecadv02001.pdf.
---------------------------------------------------------------------------

    To assess the risk of non-cancer health effects from chronic 
exposures, we summed the HQ for each of the HAP that affects a common 
target organ system to obtain the HI for that target organ system (or 
target organ-specific HI, TOSHI). The HQ is the estimated exposure 
divided by the chronic reference value, which is a value selected from 
one of several sources. First, the chronic reference level can be the 
EPA reference concentration (RfC) (https://iaspub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&vocabName=IRIS%20Glossary), 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 (ATSDR) 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://oehha.ca.gov/air/crnr/notice-adoption-air-toxics-hot-spots-program-guidance-manual-preparation-health-risk-0), 
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 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.
    As mentioned above, in order to characterize non-cancer chronic 
effects, and in response to key recommendations from the SAB, the EPA 
selects dose-response values that reflect the best available science 
for all HAP included in RTR risk assessments.\11\ More specifically, 
for a given HAP, the EPA examines the availability of inhalation 
reference values from the sources included in our tiered approach 
(e.g., IRIS first, ATSDR second, CalEPA third) and determines which 
inhalation reference value represents the best available science. Thus, 
as new inhalation reference values become available, the EPA will 
typically evaluate them and determine whether they should be given 
preference over those currently being used in RTR risk assessments.
---------------------------------------------------------------------------

    \11\ 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.
---------------------------------------------------------------------------

    The EPA also evaluated screening estimates of acute exposures and 
risks for each of the HAP (for which appropriate acute dose-response 
values are available) at the point of highest potential off-site 
exposure for each facility. To do this, the EPA estimated the risks 
when both the peak hourly emissions rate and worst-case dispersion 
conditions occur. We also assume that a person is located at the point 
of highest impact during that same time. In accordance with our mandate 
in section 112 of the CAA, we use the point of highest off-site 
exposure to assess the potential risk to the maximally exposed 
individual. 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

[[Page 95361]]

assumptions for emissions rates, meteorology, and exposure location.
    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://oehha.ca.gov/air/general-info/oehha-acute-8-hour-and-chronic-reference-exposure-level-rel-summary) is defined as ``the concentration level at 
or below which no adverse health effects are anticipated for a 
specified exposure duration.'' Id. at page 2. Acute REL values are 
based on the most sensitive, relevant, adverse health effect reported 
in the peer-reviewed medical and toxicological literature. Acute REL 
values are designed to protect the most sensitive individuals in the 
population through the inclusion of margins of safety. Because margins 
of safety are incorporated to address data gaps and uncertainties, 
exceeding the REL does not automatically indicate an adverse health 
impact.
    AEGL values were derived in response to recommendations from the 
National Research Council (NRC). The National Advisory Committee (NAC) 
for the Development of Acute Exposure Guideline Levels for Hazardous 
Substances, usually referred to as the AEGL Committee or the NAC/AEGL 
committee, developed AEGL values for at least 273 of the 329 chemicals 
on the AEGL priority chemical list. The last meeting of the NAC/AEGL 
Committee was in April 2010, and its charter expired in October 2011. 
The NAC/AEGL Committee ended in October 2011, but the AEGL program 
continues to operate at the EPA and works with the National Academies 
to publish final AEGLs, (https://www.epa.gov/aegl).
    As described in Standing Operating Procedures (SOP) of the National 
Advisory Committee on Acute Exposure Guideline Levels for Hazardous 
Chemicals (https://www.epa.gov/sites/production/files/2015-09/documents/sop_final_standing_operating_procedures_2001.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\ National Academy of Sciences (NAS), 2001. Standing 
Operating Procedures for Developing Acute Exposure Levels for 
Hazardous Chemicals, page 2.
---------------------------------------------------------------------------

    The document lays out the purpose and objectives of AEGL by stating 
that ``the primary purpose of the AEGL program and the National 
Advisory Committee for Acute Exposure Guideline Levels for Hazardous 
Substances is to develop guideline levels for once-in-a-lifetime, 
short-term exposures to airborne concentrations of acutely toxic, high-
priority chemicals.'' Id. at 21. In detailing the intended application 
of AEGL values, the document states that ``[i]t is anticipated that the 
AEGL values will be used for regulatory and 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 Emergency Response 
Planning (ERP) Committee document titled, ERPGS Procedures and 
Responsibilities (https://www.aiha.org/get-involved/AIHAGuidelineFoundation/EmergencyResponsePlanningGuidelines/Documents/ERPG%20Committee%20Standard%20Operating%20Procedures%20%20-%20March%202014%20Revision%20%28Updated%2010-2-2014%29.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 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

[[Page 95362]]

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 this source 
category, the default factor of 10 was used.
---------------------------------------------------------------------------

    \14\ Allen, et al., 2004. Variable Industrial VOC Emissions and 
their impact on ozone formation in the Houston Galveston Area. Texas 
Environmental Research Consortium. https://www.researchgate.net/publication/237593060_Variable_Industrial_VOC_Emissions 
and_their_Impact_on_Ozone_Formation_in_the_Houston_Galveston_Area.
---------------------------------------------------------------------------

    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 
for these HAP. 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. 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.
---------------------------------------------------------------------------

    \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. 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, 2009, and available online at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003.
---------------------------------------------------------------------------

4. How did we conduct the multipathway exposure and risk screening?
    The EPA conducted a screening analysis examining the potential for 
significant human health risks due to exposures via routes other than 
inhalation (i.e., ingestion). We first determined whether any sources 
in the source category emitted any HAP 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://www2.epa.gov/fera/risk-assessment-and-modeling-air-toxics-risk-assessment-reference-library).
    For the POTW source category, we identified emissions of a single 
polycyclic organic matter (POM) species, specifically 2-
methylnaphthalene. Because one or more of these PB-HAP are emitted by 
at least one facility in the POTW source category, we proceeded to the 
next step of the evaluation. In this step, we determined whether the 
facility-specific emissions rates of the emitted PB-HAP were large 
enough to create the potential for significant non-inhalation human 
health risks under reasonable worst-case conditions. To facilitate this 
step, we developed emissions rate screening levels for several PB-HAP 
using a hypothetical upper-end screening exposure scenario developed 
for use in conjunction with the EPA's Total Risk Integrated 
Methodology.Fate, Transport, and Ecological Exposure (TRIM.FaTE) model. 
The PB-HAP with emissions rate screening levels are: Lead, cadmium, 
chlorinated dibenzodioxins and furans, mercury compounds, and POM. We 
conducted a sensitivity analysis on the screening scenario to ensure 
that its key design parameters would represent the upper end of the 
range of possible values, such that it would represent a conservative, 
but not impossible scenario. The facility-specific emissions rates of 
these PB-HAP were compared to the emission rate screening levels for 
these PB-HAP to assess the potential for significant human health risks 
via non-inhalation pathways. We call this application of the TRIM.FaTE 
model the Tier 1 TRIM-screen or Tier 1 screen.
    For the purpose of developing emissions rates for our Tier 1 TRIM-
screen, we derived emission levels for these PB-HAP (other than lead 
compounds) at which the maximum excess lifetime cancer risk would be 1-
in-1 million (i.e., for polychlorinated dibenzodioxins and furans and 
POM) or, for HAP that cause non-cancer health effects (i.e., cadmium 
compounds and mercury compounds), the maximum HQ would be 1. If the 
emissions rate of any PB-HAP included in the Tier 1 screen exceeds the 
Tier 1 screening emissions rate for any facility, we conduct a second 
screen, which we call the Tier 2 TRIM-screen or Tier 2 screen.
    In the Tier 2 screen, the location of each facility that exceeded 
the Tier 1 emission rate is used to refine the assumptions associated 
with the environmental scenario while maintaining the exposure scenario 
assumptions. A key assumption that is part of the Tier 1 screen is that 
a lake is located near the facility; we confirm the existence of lakes 
near the facility as part of the Tier 2 screen. We then adjust the 
risk-based Tier 1 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 2 
screening levels are considered to pose no unacceptable risks. If the 
PB-HAP emissions for a facility exceed the Tier 2 screening emissions 
rate and data are available, we may decide to conduct a more refined 
Tier 3 multipathway

[[Page 95363]]

assessment. There are several analyses that can be included in a Tier 3 
screen depending upon the extent of refinement warranted, including 
validating that the lake is fishable and considering plume-rise to 
estimate emissions lost above the mixing layer. If the Tier 3 screen is 
exceeded, the EPA may further refine the assessment. Notably, for the 
POTW source category, emissions of POM did not exceed the Tier 1 
screening level. Therefore, the Tier 2 and 3 screening scenarios were 
not necessary.
    For further information on the multipathway analysis approach, see 
the Residual Risk Report, which is available in the docket for this 
action.
5. How did we conduct the environmental risk screening assessment?
a. Adverse Environmental Effect
    The EPA conducts a screening assessment 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 PB-HAP and two acid gases. The 
five PB-HAP are cadmium, dioxins/furans, POM, mercury (both inorganic 
mercury and methyl mercury), and lead compounds. The two acid gases are 
hydrogen chloride (HCl) and hydrogen fluoride (HF). The rationale for 
including these seven HAP in the environmental risk screening analysis 
is presented below.
    HAP that persist and bioaccumulate are of particular environmental 
concern because they accumulate in the soil, sediment, and water. The 
PB-HAP are taken up, through sediment, soil, water, and/or ingestion of 
other organisms, by plants or animals (e.g., small fish) at the bottom 
of the food chain. As larger and larger predators consume these 
organisms, concentrations of the PB-HAP in the animal tissues increases 
as does the potential for adverse effects. The five PB-HAP we evaluate 
as part of our screening analysis account for 99.8 percent of all PB-
HAP emissions nationally from stationary sources (on a mass basis from 
the 2005 EPA NEI).
    In addition to accounting for almost all of the mass of PB-HAP 
emitted, we note that the TRIM.FaTE model that we use to evaluate 
multipathway risk allows us to estimate concentrations of cadmium 
compounds, dioxins/furans, POM, and mercury in soil, sediment, and 
water. For lead compounds, we currently do not have the ability to 
calculate these concentrations using the TRIM.FaTE model. Therefore, to 
evaluate the potential for adverse environmental effects from lead 
compounds, we compare the estimated HEM-modeled exposures from the 
source category emissions of lead with the level of the secondary 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 the U.S. In addition to the 
potential to cause direct damage to plants, high concentrations of HF 
in the air have been linked to fluorosis in livestock. Air 
concentrations of these HAP are already calculated as part of the human 
multipathway exposure and risk screening analysis using the HEM3-AERMOD 
air dispersion model, and we are able to use the air dispersion 
modeling results to estimate the potential for an adverse environmental 
effect.
    The EPA acknowledges that other HAP beyond the seven HAP discussed 
above may have the potential to cause adverse environmental effects. 
Therefore, the EPA may include other relevant HAP in its environmental 
risk screening in the future, as modeling science and resources allow. 
The EPA invites comment on the extent to which other HAP emitted by the 
source category may cause adverse environmental effects. Such 
information should include references to peer-reviewed ecological 
effects benchmarks that are of sufficient quality for making regulatory 
decisions, as well as information on the presence of organisms located 
near facilities within the source category that such benchmarks 
indicate could be adversely affected.
c. Ecological Assessment Endpoints and Benchmarks for PB-HAP
    An important consideration in the development of the EPA's 
screening methodology is the selection of ecological assessment 
endpoints and benchmarks. Ecological assessment endpoints are defined 
by the ecological entity (e.g., aquatic communities, including fish and 
plankton) and its attributes (e.g., frequency of mortality). Ecological 
assessment endpoints can be established for organisms, populations, 
communities or assemblages, and ecosystems.
    For PB-HAP (other than lead compounds), we evaluated the following 
community-level ecological assessment endpoints to screen for organisms 
directly exposed to HAP in soils, sediment, and water:
     Local terrestrial communities (i.e., soil invertebrates, 
plants) and populations of small birds and mammals that consume soil 
invertebrates exposed to PB-HAP in the surface soil;
     Local benthic (i.e., bottom sediment dwelling insects, 
amphipods, isopods, and crayfish) communities exposed to PB-HAP in 
sediment in nearby water bodies; and
     Local aquatic (water-column) communities (including fish 
and plankton) exposed to PB-HAP in nearby surface waters.
    For PB-HAP (other than lead compounds), we also evaluated the 
following population-level ecological assessment endpoint to screen for 
indirect HAP exposures of top consumers via the bioaccumulation of HAP 
in food chains:
     Piscivorous (i.e., fish-eating) wildlife consuming PB-HAP-
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 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;

[[Page 95364]]

     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; and
     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 
in the analysis, if available. If not, the EPA benchmarks used in 
regional programs (e.g., Superfund) were used. If benchmarks were not 
available at a programmatic or regional level, we used benchmarks 
developed by other federal agencies (e.g., National Oceanic and 
Atmospheric Administration (NOAA)) or state agencies.
    Benchmarks for all effect levels are not available for all PB-HAP 
and assessment endpoints. In cases where multiple effect levels were 
available for a particular PB-HAP and assessment endpoint, we use all 
of the available effect levels to help us to determine whether 
ecological risks exist and, if so, whether the risks could be 
considered significant and widespread.
d. Ecological Assessment Endpoints and Benchmarks for Acid Gases
    The environmental screening analysis also evaluated potential 
damage and reduced productivity of plants due to direct exposure to 
acid gases in the air. For acid gases, we evaluated the following 
ecological assessment endpoint:
     Local terrestrial plant communities with foliage exposed 
to acidic gaseous HAP in the air.
    The selection of ecological benchmarks for the effects of acid 
gases on plants followed the same approach as for PB-HAP (i.e., we 
examine all of the available chronic benchmarks). For HCl, the EPA 
identified chronic benchmark concentrations. We note that the benchmark 
for chronic HCl exposure to plants is greater than the reference 
concentration for chronic inhalation exposure for human health. This 
means that where the EPA includes regulatory requirements to prevent an 
exceedance of the reference concentration for human health, additional 
analyses for adverse environmental effects of HCl would not be 
necessary.
    For HF, the EPA identified chronic benchmark concentrations for 
plants and evaluated chronic exposures to plants in the screening 
analysis. High concentrations of HF in the air have also been linked to 
fluorosis in livestock. However, the HF concentrations at which 
fluorosis in livestock occur are higher than those at which plant 
damage begins. Therefore, the benchmarks for plants are protective of 
both plants and livestock.
e. Screening Methodology
    For the environmental risk screening analysis, the EPA first 
determined whether any facilities in the POTW source category emitted 
any of the seven environmental HAP. For the POTW source category, we 
identified emissions of a single POM species, specifically 2-
methylnaphthalene.
    Because one or more of the seven environmental HAP evaluated are 
emitted by at least one facility in the source category, we proceeded 
to the second step of the evaluation.
f. PB-HAP Methodology
    For cadmium, mercury, POM, and dioxins/furans, the environmental 
screening analysis consists of two tiers, while lead compounds are 
analyzed differently as discussed earlier. In the first tier, we 
determined whether the maximum facility-specific emission rates of each 
of the emitted environmental HAP were large enough to create the 
potential for adverse environmental effects under reasonable worst-case 
environmental conditions. These are the same environmental conditions 
used in the human multipathway exposure and risk screening analysis.
    To facilitate this step, TRIM.FaTE was run for each PB-HAP under 
hypothetical environmental conditions designed to provide 
conservatively high HAP concentrations. The model was set to maximize 
runoff from terrestrial parcels into the modeled lake, which in turn, 
maximized the chemical concentrations in the water, the sediments, and 
the fish. The resulting media concentrations were then used to back-
calculate a screening level 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 level emission rate 
for that PB-HAP for each assessment endpoint. If emissions from a 
facility do not exceed the Tier 1 screening level, the facility 
``passes'' the screen, and, therefore, is not evaluated further under 
the screening approach. If emissions from a facility exceed the Tier 1 
screening level, we evaluate the facility further in Tier 2.
    In Tier 2 of the environmental screening analysis, the emission 
rate screening levels are adjusted to account for local meteorology and 
the actual location of lakes in the vicinity of facilities that did not 
pass the Tier 1 screen. The modeling domain for each facility in the 
Tier 2 analysis consists of 8 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 one lake with modeled concentrations for water, sediment, 
and fish tissue. In the Tier 2 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 2 screening level, the facility passes 
the screen, and typically is not evaluated further. If emissions from a 
facility exceed the Tier 2 screening level, 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. Notably, for the POTW source category, emissions of 
POM did not exceed the Tier 1 ecological screening level. Therefore, 
the Tier 2 screen was not necessary.
    For further information on the environmental screening analysis 
approach, see the Residual Risk Report, which is available in the 
docket for this action.
6. 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 from all other 
emission sources at the facility for which we have data. Using the most 
current available NEI data at the time of the analysis, the EPA 
developed ``facility-wide'' emissions estimates. For this category, the 
latest available version of the NEI was the 2011 NEI Version 2. It is 
important to note that the NEI

[[Page 95365]]

facility-wide inventory may not always reflect the level of detail or 
be representative of the same temporal period that is found in the 
source category specific inventory. Further information on the NEI, 
which is developed from state/local/tribal submitted data, can be found 
on the EPA's Web site at: https://www.epa.gov/air-emissions-inventories/national-emissions-inventory.
    We analyzed risks due to the inhalation of HAP that are emitted 
facility-wide for the populations residing within 50 km of each 
facility, consistent with the methods used for the source category 
analysis described above. For these facility-wide risk analyses, the 
modeled source category risks were compared to the facility-wide risks 
to determine the portion of facility-wide risks that could be 
attributed to the source category addressed in this proposal. We 
specifically examined the facility that was associated with the highest 
estimate of risk and determined the percentage of that risk 
attributable to the source category of interest. The Residual Risk 
Report, available through the docket for this action, provides the 
methodology and results of the facility-wide analyses, including all 
facility-wide risks and the percentage of source category contribution 
to facility-wide risks.
7. How did we consider uncertainties in risk assessment?
    In the Benzene NESHAP, we concluded that risk estimation 
uncertainty should be considered in our decision-making under the ample 
margin of safety framework. Uncertainty and the potential for bias are 
inherent in all risk assessments, including those performed for this 
proposal. Although uncertainty exists, we believe that our approach, 
which used conservative tools and assumptions, ensures that our 
decisions are health protective and environmentally protective. A brief 
discussion of the uncertainties in the RTR emissions dataset, 
dispersion modeling, inhalation exposure estimates, and dose-response 
relationships follows below. A more thorough discussion of these 
uncertainties is included in the Residual Risk Report, which is 
available in the docket for this action.
a. Uncertainties in the RTR Emissions Dataset
    Although the development of the RTR emissions dataset involved 
quality assurance/quality control processes, the accuracy of emissions 
values will vary depending on the source of the data, the degree to 
which data are incomplete or missing, the degree to which assumptions 
made to complete the datasets are accurate, errors in emission 
estimates, and other factors. The emission estimates considered in this 
analysis generally are annual totals for certain years, and they do not 
reflect short-term fluctuations during the course of a year or 
variations from year to year. The estimates of peak hourly emission 
rates for the acute effects screening assessment were based on an 
emission adjustment factor applied to the average annual hourly 
emission rates, which are intended to account for emission fluctuations 
due to normal facility operations.
b. Uncertainties in Dispersion Modeling
    We recognize there is uncertainty in ambient concentration 
estimates associated with any model, including the EPA's recommended 
regulatory dispersion model, AERMOD. In using a model to 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 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 micro-environment 
to another over the course of hours or days. Long-term mobility is 
movement from one residence to another over the course of a 
lifetime.
---------------------------------------------------------------------------

    In addition, the assessment predicted the chronic exposures at the 
centroid of each populated census block as surrogates for the exposure 
concentrations for all people living in that block. Using the census 
block centroid to predict chronic exposures tends to over-predict 
exposures for people in the census block who live farther from the 
facility and under-predict exposures for people in the census block who 
live closer to the facility. Thus, using the census block centroid to 
predict chronic exposures may lead to a potential understatement or 
overstatement of the true maximum impact, but is an unbiased estimate 
of average risk and incidence. We reduce this uncertainty by analyzing 
large census blocks near facilities using aerial imagery and adjusting 
the location of the block centroid to better represent the population 
in the block, as well as adding additional receptor locations where the 
block population is not well represented by a single location.
    The assessment evaluates the cancer inhalation risks associated 
with pollutant exposures over a 70-year period, which is the assumed 
lifetime of an individual. In reality, both the length of time that 
modeled emission sources at facilities actually operate (i.e., more or 
less than 70 years) and the domestic growth or decline of the modeled 
industry (i.e., the increase or decrease in the number or size of 
domestic facilities) will influence the future risks posed by a given 
source or source category. Depending on the characteristics of the 
industry, these factors will, in most cases, result in an overestimate 
both in individual risk levels and in the total estimated number of 
cancer cases. However, in the unlikely scenario where a facility 
maintains, or even increases, its emissions levels over a period of 
more than 70 years, residents live beyond 70 years at the same 
location, and the residents spend most of their days at that location, 
then the cancer inhalation risks could potentially be underestimated. 
However, annual cancer incidence estimates from exposures to emissions 
from these sources would not be affected by the length of time an 
emissions source operates.
    The exposure estimates used in these analyses assume chronic 
exposures to ambient (outdoor) levels of pollutants. Because most 
people spend the majority

[[Page 95366]]

of their time indoors, actual exposures may not be as high, depending 
on the characteristics of the pollutants modeled. For many of the HAP, 
indoor levels are roughly equivalent to ambient levels, but for very 
reactive pollutants or larger particles, indoor levels are typically 
lower. This factor has the potential to result in an overestimate of 25 
to 30 percent of exposures.\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 the EPA 
conducts as part of the risk review under section 112 of the CAA 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 the presence of humans at the location of the maximum 
concentration. In the acute screening assessment that we conduct under 
the RTR program, we assume that peak emissions from the source category 
and worst-case meteorological conditions co-occur, thus, resulting in 
maximum ambient concentrations. These two events are unlikely to occur 
at the same time, making these assumptions conservative. We then 
include the additional assumption that a person is located at this 
point during this same time period. For this source category, 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 when peak emissions and worst-case 
meteorological conditions occur simultaneously.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from 
chronic exposures and non-cancer effects from both chronic and acute 
exposures. Some uncertainties may be considered quantitatively, and 
others generally are expressed in qualitative terms. We note as a 
preface to this discussion a point on dose-response uncertainty that is 
brought out in the EPA's 2005 Cancer Guidelines; namely, that ``the 
primary goal of EPA actions is protection of human health; accordingly, 
as an Agency policy, risk assessment procedures, including default 
options that are used in the absence of scientific data to the 
contrary, should be health protective'' (EPA's 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 Residual Risk Report, which is available in the docket for this 
action.
    Cancer URE values used in our risk assessments are those that have 
been developed to generally provide an upper bound estimate of risk. 
That is, they represent a ``plausible upper limit to the true value of 
a quantity'' (although this is usually not a true statistical 
confidence limit).\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 (https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&glossaryName=IRIS%20Glossary).
    \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 and 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, An Examination of EPA Risk 
Assessment Principles and Practices, EPA/100/B-04/001, 2004, 
available at https://nctc.fws.gov/resources/course-resources/pesticides/Risk%20Assessment/Risk%20Assessment%20Principles%20and%20Practices.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

[[Page 95367]]

the purpose for the reference value (see the following paragraph). The 
UF applied in acute reference value derivation include: (1) 
Heterogeneity among humans; (2) uncertainty in extrapolating from 
animals to humans; (3) uncertainty in lowest observed adverse effect 
(exposure) level to no observed adverse effect (exposure) level 
adjustments; and (4) uncertainty in accounting for an incomplete 
database on toxic effects of potential concern. Additional adjustments 
are often applied to account for uncertainty in extrapolation from 
observations at one exposure duration (e.g., 4 hours) to derive an 
acute reference value at another exposure duration (e.g., 1 hour).
    Not all acute reference values are developed for the same purpose, 
and care must be taken when interpreting the results of an acute 
assessment of human health effects relative to the reference value or 
values being exceeded. Where relevant to the estimated exposures, the 
lack of short-term dose-response values at different levels of severity 
should be factored into the risk characterization as potential 
uncertainties.
    Although every effort is made to identify appropriate human health 
effect dose-response assessment values for all pollutants emitted by 
the sources in this risk assessment, some HAP emitted by this source 
category are lacking dose-response assessments. Accordingly, these 
pollutants cannot be included in the quantitative risk assessment, 
which could result in quantitative estimates understating HAP risk. To 
help to alleviate this potential underestimate, where we conclude 
similarity with a HAP for which a dose-response assessment value is 
available, we use that value as a surrogate for the assessment of the 
HAP for which no value is available. To the extent use of surrogates 
indicates appreciable risk, we may identify a need to increase priority 
for new IRIS assessment of that substance. We additionally note that, 
generally speaking, HAP of greatest concern due to environmental 
exposures and hazard are those for which dose-response assessments have 
been performed, reducing the likelihood of understating risk. Further, 
HAP not included in the quantitative assessment are assessed 
qualitatively and considered in the risk characterization that informs 
the risk management decisions, including with regard to consideration 
of HAP reductions achieved by various control options.
    For a group of compounds that are 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 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 three-tiered screening analysis that relies 
on the outputs from models that estimate environmental pollutant 
concentrations and human exposures for four PB-HAP. Two important types 
of uncertainty associated with the use of these models in RTR risk 
assessments and inherent to any assessment that relies on environmental 
modeling are model uncertainty and input uncertainty.\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 SAB 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 
1 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 datasets 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 2 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 1. By refining the screening approach in 
Tier 2 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 1 and Tier 2.
    For both Tiers 1 and 2 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 1 and 2 
screening methods, refer to the risk document, Appendix 2, Technical 
Support Document for TRIM-Based Multipathway Tiered Screening 
Methodology for RTR: Summary and Evaluation.
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

[[Page 95368]]

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 SAB 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 
1 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 datasets 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 1, we used the maximum facility-specific 
emissions for the PB-HAP (other than lead compounds, which were 
evaluated by comparison to the secondary lead NAAQS) that were included 
in the environmental screening assessment and each of the media when 
comparing to ecological benchmarks. This is consistent with the 
conservative design of Tier 1 of the screen. In Tier 2 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 2 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 2 to obtain one average soil 
concentration value for each facility and for each PB-HAP. For PB-HAP 
concentrations in water, sediment, and fish tissue, the highest value 
for each facility for each pollutant is used.
    For the environmental screening assessment for acid gases, we 
employ a single-tiered approach. We use the modeled air concentrations 
and compare those with ecological benchmarks.
    For both Tiers 1 and 2 of the environmental screening assessment, 
our approach to addressing model input uncertainty is generally 
cautious. We choose model inputs from the upper end of the range of 
possible values for the influential parameters used in the models, and 
we assume that the exposed individual exhibits ingestion behavior that 
would lead to a high total exposure. This approach reduces the 
likelihood of not identifying potential risks for adverse environmental 
impacts.
    Uncertainty also exists in the ecological benchmarks for the 
environmental risk screening analysis. We established a hierarchy of 
preferred benchmark sources to allow selection of benchmarks for each 
environmental HAP at each ecological assessment endpoint. In general, 
EPA benchmarks used at a programmatic level (e.g., Office of Water, 
Superfund Program) were used if available. If not, we used EPA 
benchmarks used in regional programs (e.g., Superfund Program). If 
benchmarks were not available at a programmatic or regional level, we 
used benchmarks developed by other agencies (e.g., NOAA) or by state 
agencies.
    In all cases (except for lead compounds, which were evaluated 
through a comparison to the NAAQS), we searched for benchmarks at the 
following three effect levels, as described in section III.A.5 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 evaluates 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, 
where applicable. These seven HAP represent pollutants that can cause 
adverse impacts for plants and animals either through direct exposure 
to HAP in the air or through exposure to HAP that is deposited from the 
air onto soils and surface waters. These seven HAP also represent those 
HAP for which we can conduct a meaningful environmental risk screening 
assessment. For other HAP not included in our screening assessment, the 
model has not been parameterized such that it can be used for that 
purpose. In some cases, depending on the HAP, we may not have 
appropriate multipathway models that allow us to predict the 
concentration of that pollutant. The EPA acknowledges that other HAP 
beyond the seven HAP that we are evaluating may have the potential to 
cause adverse environmental effects and, therefore, the EPA may 
evaluate other relevant HAP in the future, as modeling science and 
resources allow.
    Further information on uncertainties and the Tier 1 and 2 
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 Residual Risk Report, 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 CAA section 112(f)(2), we apply a two-step 
process to address residual risk. In the first step, the EPA

[[Page 95369]]

determines whether risks are acceptable. This determination ``considers 
all health information, including risk estimation uncertainty, and 
includes a presumptive limit on maximum individual lifetime [cancer] 
risk (MIR) \25\ of approximately [1-in-10 thousand] [i.e., 100-in-1 
million].'' 54 FR 38045, September 14, 1989. If risks are unacceptable, 
the EPA must determine the emissions standards necessary to bring risks 
to an acceptable level without considering costs. In the second step of 
the process, the EPA considers whether the emissions standards provide 
an ample margin of safety ``in consideration of all health information, 
including the number of persons at risk levels higher than 
approximately 1-in-1 million, as well as other relevant factors, 
including costs and economic impacts, technological feasibility, and 
other factors relevant to each particular decision.'' Id. The EPA must 
promulgate emission standards necessary to provide an ample margin of 
safety. After conducting the ample margin of safety analysis, we 
consider whether a more stringent standard is necessary to prevent, 
taking into consideration, costs, energy, safety, and other relevant 
factors, an adverse environmental effect.
---------------------------------------------------------------------------

    \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; and 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 action.
    The Agency is considering these various measures of health 
information to inform our determinations of risk acceptability and 
ample margin of safety under CAA section 112(f). As explained in the 
Benzene NESHAP, ``the first step judgment on acceptability cannot be 
reduced to any single factor'' and, thus, ``[t]he Administrator 
believes that the acceptability of risk under [previous] section 112 is 
best judged on the basis of a broad set of health risk measures and 
information.'' 54 FR 38046, September 14, 1989. Similarly, with regard 
to the ample margin of safety determination, ``the Agency again 
considers all of the health risk and other health information 
considered in the first step. Beyond that information, additional 
factors relating to the appropriate level of control will also be 
considered, including cost and economic impacts of controls, 
technological feasibility, uncertainties, and any other relevant 
factors.'' Id.
    The Benzene NESHAP approach provides flexibility regarding factors 
the EPA may consider in making determinations and how the EPA may weigh 
those factors for each source category. In responding to comment on our 
policy under the Benzene NESHAP, the EPA explained that:

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

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

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[[Page 95370]]

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

C. How did we perform the technology review?

    Our technology review focused on the identification and evaluation 
of developments in practices, processes, and control technologies that 
have occurred since the MACT standards were promulgated. Where we 
identified such developments, in order to inform our decision of 
whether it is ``necessary'' to revise the emissions standards, we 
analyzed the technical feasibility of applying these developments and 
the estimated costs, energy implications, non-air environmental 
impacts, as well as considering the emission reductions. We also 
considered the appropriateness of applying controls to new sources 
versus retrofitting existing sources.
    Based on our analyses of the available data and information, we 
identified potential developments in practices, processes, and control 
technologies. For this exercise, we considered any of the following to 
be a ``development'':
     Any add-on control technology or other equipment that was 
not identified and considered during development of the original MACT 
standards;
     Any improvements in add-on control technology or other 
equipment (that were identified and considered during development of 
the original MACT standards) that could result in additional emissions 
reduction;
     Any work practice or operational procedure that was not 
identified or considered during development of the original MACT 
standards;
     Any process change or pollution prevention alternative 
that could be broadly applied to the industry and that was not 
identified or considered during development of the original MACT 
standards; and
     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).
    In addition to reviewing the practices, processes, and control 
technologies that were considered at the time we originally developed 
(or last updated) the NESHAP, we reviewed a variety of data sources in 
our investigation of potential practices, processes, or controls to 
consider. Among the sources we reviewed were the NESHAP for various 
industries that were promulgated since the MACT standards 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 emission sources in the POTW source 
category, as well as the costs, non-air impacts, and energy 
implications associated with the use of these technologies. 
Additionally, we requested information from facilities regarding 
developments in practices, processes, or control technology. Finally, 
we reviewed information from other sources, such as state and/or local 
permitting agency databases and industry-supported databases.

IV. Analytical Results and Proposed Decisions

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

1. Inhalation Risk Assessment Results
    Table 2 of this preamble provides an overall summary of the results 
of the inhalation risk assessment.

                                                    Table 2--POTW Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                          Estimated
                                           Estimated population at      annual cancer      Maximum
Maximum individual cancer risk (1-in-1     increased risk levels of       incidence     chronic non-       Maximum screening acute non-cancer HQ \3\
             million) \1\                           cancer               (cases per     cancer TOSHI
                                                                            year)            \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Actual Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
0.8...................................  >= 1-in-1 million: 0.........          0.0006           0.007  HQREL = 2 (formaldehyde).
                                        >= 10-in-1 million: 0
                                        >= 100-in-1 million: 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Allowable Emissions \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
2.....................................  >= 1-in-1 million: 240.......           0.001            0.01
                                        >= 10-in-1 million: 0
                                        >= 100-in-1 million: 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimated maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\2\ Maximum TOSHI. The target organ with the highest TOSHI for POTW source category for both actual and allowable emissions is the respiratory system.
\3\ See section III.A.3 of this preamble for explanation of acute dose-response values. Acute assessments are not performed on allowable emissions.
\4\ The development of allowable emission estimates can be found in the memorandum titled Inputs to the Publicly Owned Treatment Works March 2016
  Residual Risk Modeling, June 2016 (Modeling Inputs Memo), which is available in the docket.

[[Page 95371]]

    The results of the chronic baseline inhalation cancer risk 
assessment indicate that, based on estimates of current actual 
emissions, the MIR posed for the POTW source category is 0.8-in-1 
million, with emissions of formaldehyde from the primary clarifier 
accounting for the majority of the risk. The total estimated cancer 
incidence from POTW based on actual emission levels is 0.0006 excess 
cancer cases per year or one case every 1,667 years, with emissions of 
formaldehyde and acrylonitrile contributing 50 percent and 21 percent, 
respectively, to the cancer incidence.
    When considering MACT-allowable emissions, the MIR is estimated to 
be up to 2-in-1 million, driven by emissions of formaldehyde from the 
primary clarifier. The cancer incidence is estimated to be 0.001 excess 
cancer cases per year, or one excess case in every 1,000 years. 
Approximately 240 people are estimated to have cancer risks greater 
than or equal to 1-in-1 million considering allowable emissions from 
the POTW source category.
    The maximum modeled chronic non-cancer HI (TOSHI) for the source 
category based on actual emissions is estimated to be 0.007, driven by 
formaldehyde emissions from the primary clarifier. When considering 
MACT-allowable emissions, the maximum chronic non-cancer TOSHI is 
estimated to be 0.01, driven by formaldehyde emissions.
2. Acute Risk Results
    Our screening analysis for worst-case acute impacts based on actual 
emissions indicates the potential for one pollutant, formaldehyde, from 
one facility, to have an HQ above 1, based on the formaldehyde REL. Six 
out of seven POTW treatment plants had an estimated worst-case HQ less 
than or equal to 1 for all HAP.
    To better characterize the potential health risks associated with 
the estimated worst-case acute exposure to HAP from the POTW source 
category, and in response to a key recommendation from the SAB's peer 
review of the EPA's CAA section 112(f) RTR risk assessment 
methodologies, we examine a wider range of available acute health 
metrics than we do for our chronic risk assessments. This is because 
there generally are greater uncertainties associated with the use of 
acute reference values.
    By definition, the acute CalEPA REL represents a health-protective 
level of exposure, with no risk anticipated below those levels, even 
for repeated exposures; however, the health risk from higher-level 
exposures is unknown. Therefore, when a CalEPA REL is exceeded and an 
AEGL-1 or ERPG-1 level (i.e., levels at which mild effects are 
anticipated in the general public for a single exposure) is available, 
we have used them as a second comparative measure. For the purpose of 
characterizing public health risks in RTR assessments, we typically 
have not compared estimated maximum off-site 1-hour exposure levels to 
occupational levels. This is because occupational ceiling values are 
not generally considered protective for the general public since they 
are designed to protect the worker population (presumed healthy adults) 
against short-duration (less than 15-minutes) exposures. As a result, 
for most chemicals, the 15-minute occupational ceiling values are 
higher than a 1-hour AEGL-1 and/or ERPG-1, making comparisons to them 
irrelevant unless the AEGL-1 or ERPG-1 levels are also exceeded.
    The worst-case maximum estimated 1-hour exposure to formaldehyde 
outside the POTW treatment plant fenceline exceeds the 1-hour REL by 
about a factor of 2 (HQREL=2) but is substantially less than 
the AEGL-1 and ERPG-1 values for formaldehyde (HQAEGL-1 = 
0.2 and HQERPG-1 = 0.2). All other HAP in this analysis have 
worst-case acute HQs of 1 or less, indicating little to no potential 
for acute health risk.
    In characterizing the potential for acute non-cancer impacts of 
concern, it is important to remember the upward bias of these exposure 
estimates. First, peak 1-hour emissions were conservatively assumed to 
be 10 times the annual emission rate. It was then assumed that 
emissions from all emission points at a given POTW peaked concurrently, 
and at the same time worst-case hourly meteorology was occurring. 
Finally, it was assumed that a person would be located at the point of 
maximum concentration for at least an hour. When these factors are 
taken together, there is likely little potential for acute health risk 
from POTW emissions.
3. Multipathway Risk Screening Results
    PB-HAP emissions of 2-methylnaphthalene (i.e., the only PB-HAP 
emitted from the POTW source category) did not exceed the worst-case 
Tier I screening emission rate. No other PB-HAP are emitted by any 
source in the source category.
4. Environmental Risk Screening Results
    As described in section III.A of this preamble, we conducted a 
screening-level evaluation of the potential for adverse environmental 
effects associated with emissions of 2-methylnaphthalene.
    In the Tier 1 screening analysis for 2-methylnaphthalene, the 
modeled Tier 1 concentrations of this PB-HAP did not exceed any 
ecological benchmarks for any POTW in the source category.
5. Facility-Wide Risk Results
    The facility-wide chronic MIR and TOSHI were estimated based on 
emissions from all sources at the identified facilities (both MACT and 
non-MACT sources). The results of the facility-wide assessment of 
cancer risks indicate that three facilities with POTW operations have a 
facility-wide cancer MIR greater than or equal to 1-in-1 million. The 
maximum facility-wide cancer MIR is 10-in-1 million, primarily driven 
by formaldehyde. The maximum facility-wide TOSHI for the source 
category is estimated to be 0.09, primarily driven by emissions of 
formaldehyde.
6. What demographic groups might benefit from this regulation?
    To examine the potential for any environmental justice (EJ) 
concerns that might be associated with the source category, we 
performed a demographic analysis of the population close to the 
facilities. In this analysis, we evaluated the distribution of HAP-
related cancer and non-cancer risks from the POTW 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, Risk and Technology Review--Analysis of 
Socio-Economic Factors for Populations Living Near POTW Facilities, 
available in the docket for this action.
    The results of the demographic analysis are summarized in Table 3 
of this preamble. 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.

[[Page 95372]]

                                 Table 3--POTW Demographic Risk Analysis Results
----------------------------------------------------------------------------------------------------------------
                                                                                    Population
                                                                                    with cancer     Population
                                                                                    risk at or     with chronic
                                                                    Nationwide     above 1-in-1    hazard index
                                                                                  million due to  above 1 due to
                                                                                       POTW            POTW
----------------------------------------------------------------------------------------------------------------
Total Population................................................     312,861,265               0               0
----------------------------------------------------------------------------------------------------------------
                                                 Race by Percent
----------------------------------------------------------------------------------------------------------------
White...........................................................              72               0               0
All Other Races.................................................              28               0               0
----------------------------------------------------------------------------------------------------------------
                                                 Race by Percent
----------------------------------------------------------------------------------------------------------------
White...........................................................              72               0               0
African American................................................              13               0               0
Native American.................................................             1.1               0               0
Other and Multiracial...........................................              14               0               0
----------------------------------------------------------------------------------------------------------------
                                              Ethnicity by Percent
----------------------------------------------------------------------------------------------------------------
Hispanic........................................................              17               0               0
Non-Hispanic....................................................              83               0               0
----------------------------------------------------------------------------------------------------------------
                                                Income by Percent
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................................              14               0               0
Above Poverty Level.............................................             +86               0               0
----------------------------------------------------------------------------------------------------------------
                                              Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 and without High School Diploma.........................              15               0               0
Over 25 and with a High School Diploma..........................              85               0               0
----------------------------------------------------------------------------------------------------------------

    The results of the POTW source category demographic analysis 
indicate that emissions from the source category expose no person to a 
cancer risk at or above 1-in-1 million or to a chronic non-cancer TOSHI 
greater than 1. The demographics of the population living within 50 km 
of POTW can be found in Table 2 of the document: Risk and Technology 
Review--Analysis of Socio-Economic Factors for Populations Living Near 
Publicly Owned Treatment Works.

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

1. Risk Acceptability
    As noted in section II.A.1 of this preamble, the EPA sets standards 
under CAA section 112(f)(2) using ``a two-step standard-setting 
approach, with an analytical first step to determine an `acceptable 
risk' that considers all health information, including risk estimation 
uncertainty, and includes a presumptive limit on MIR of approximately 1 
in 10 thousand.'' 54 FR 38045, September 14, 1989.
    In determining whether risks are acceptable for the POTW source 
category, the EPA considered all available health information including 
any uncertainty in risk estimates. Also, as noted in section IV.A of 
this preamble, the Agency estimated risk from both actual and allowable 
emissions. While there are uncertainties associated with both the 
actual and allowable emissions, we consider the allowable emissions to 
be an upper bound, based on the conservative methods we used to 
calculate allowable emissions.
    The estimated inhalation cancer risk based on actual emissions is 
less than 1-in-1 million. Additionally, the estimated inhalation cancer 
risk based on allowable emissions is 10-in-1 million. Both of these 
results are considerably less than the presumptive limit of 
acceptability (i.e., 100-in-1 million). The maximum chronic inhalation 
non-cancer hazard indices for both the actual and allowable emissions 
are less than 1, indicating that chronic exposures are without 
appreciable risk of non-cancer health effects.
    The multipathway screening analysis indicates that PB-HAP emissions 
did not exceed the screening emission rates for any PB-HAP evaluated.
    The screening assessment of worst-case acute inhalation exposures 
resulting from actual emissions indicates that the worst-case maximum 
estimated 1-hour exposure to formaldehyde outside the facility fence 
line exceeds the 1-hour REL by a factor of 2 (HQREL = 2). It 
is important to note that this highest offsite HQ value assumes an 
hourly emissions multiplier of 10 times the annual emissions rate, 
while also assuming that a person will be present at the location of 
highest exposure for at least 1 hour when emissions from all emission 
points are at their peak. We further assume these peak emissions are 
occurring at same time worst-case meteorology is occurring. Finally, it 
is important to note that this conservatively estimated 1-hour 
formaldehyde concentration is well below the AEGL-1 and ERPG-1 for 
formaldehyde. Taken together, we believe there is little potential for 
acute health risk from formaldehyde. All other HAP in this analysis 
have worst-case acute HQ values outside facility fencelines of 1 or 
less indicating little potential risk of acute health effects.
    Considering all of the health risk information and factors 
discussed above, including the uncertainties discussed in section 
III.A.7 of this preamble, the EPA proposes that additional standards 
are not necessary to bring risk to an acceptable level because cancer 
risks are well below the presumptive limit of acceptability, and

[[Page 95373]]

other health risk information indicates there is minimal likelihood of 
adverse non-cancer (including chronic, acute, and multipathway) health 
effects due to HAP emissions from this source category.
2. Ample Margin of Safety Analysis
    In the ample margin of safety analysis, we evaluate available 
control technologies and other measures (including those evaluated 
under the technology review, as well as the risk reductions achieved by 
such potential additional measures, to determine whether additional 
standards are required to reduce risks further. In conducting the ample 
margin of safety analysis we consider the costs and economic impacts 
and technological feasibility of additional standards.
    We are proposing that the 2002 POTW NESHAP requirements provide an 
ample margin of safety to protect public health. As explained in 
section IV.A of this preamble, we estimate that the MIR in the exposed 
population is less than 1-in-1 million at the actual emission levels. 
Additionally, the chronic non-cancer TOSHI is less than 1 and there is 
negligible potential for acute risk. Thus, EPA proposes that standards 
in the 2002 POTW NESHAP achieve the goal of providing the maximum 
feasible protection against risks to health from HAP.
    Moreover, as noted in our discussion of the technology review in 
section IV.C of this preamble, no additional measures were identified 
for reducing HAP emissions from the POTW source category. Therefore, we 
propose that the 2002 standards provide an ample margin of safety to 
protect public health.
    Although we are proposing to find that the 2002 standards provide 
an ample margin of safety to protect public health, we are proposing 
additional standards under CAA section 112(d)(6) that address HAP 
emissions from collection systems and all treatment units located at 
the POTW treatment plant. This is described more fully in Section 
IV.C.1 below. We are proposing that POTW develop and implement 
pretreatment programs to reduce organic HAP emissions from collection 
systems as wastewater is conveyed from an industrial user to the POTW 
treatment plant. All of the POTW identified as subject to the POTW 
NESHAP already have pretreatment programs in place; therefore, no 
additional emission reductions are expected. However, requiring control 
of emissions from collection systems by implementing pretreatment 
programs will allow POTW to limit potential future increases in 
emissions since the POTW will set limits on pollutants discharged to 
collection systems from industrial users. As noted above, we are 
proposing that the MACT standards, prior to the implementation of these 
proposed standards for collection systems, provide an ample margin of 
safety to protect public health. Therefore, we are proposing that, 
after the implementation of these standards for collection systems, the 
rule will continue to provide an ample margin of safety to protect 
public health. Consequently, it will not be necessary to conduct 
another residual risk review under CAA section 112(f) for this source 
category 8 years following promulgation of the new standards for 
collection systems, merely due to the addition of these MACT 
requirements. While our decisions on risk acceptability and ample 
margin of safety are supported even in the absence of these standards 
for collection systems, if we finalize the proposed requirements for 
these emission sources they will further strengthen our conclusions 
that risk is acceptable and the standards provide an ample margin of 
safety to protect public health.
    Although we did not identify any new technologies to reduce risk 
for this source category, we are specifically requesting comment on 
whether there are additional control measures that may be able to 
reduce risks from the source category. We request any information on 
potential emission reductions of such measures, as well as the cost and 
health impacts of such reductions to the extent they are known.
3. Adverse Environmental Effects
    Based on the results of our environmental risk screening 
assessment, we conclude that there is not an adverse environmental 
effect as a result of HAP emissions from the POTW source category. We 
are proposing 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?

    As described in section III.C of this preamble, our technology 
review focused on identifying developments in the practices, processes, 
and control technologies for the POTW source category. The EPA reviewed 
various information sources regarding POTW emission sources that are 
currently regulated by the POTW NESHAP, which include, but are not 
limited to, influent waste stream conveyance channels, bar screens, 
grit chambers, grinders, pump stations, aerated feeder channels, 
primary clarifiers, primary effluent channels, and primary screening 
stations.
    As discussed further in sections II.C and D of this preamble, we 
conducted a search of the RBLC Clearinghouse, other regulatory actions 
(MACT standards, area source standards, and residual risk standards) 
subsequent to promulgation of the 2002 POTW NESHAP, literature related 
to research conducted for emission reductions from POTW emission 
sources, and state permits. Further, we reviewed the responses to the 
2015 ICR to determine the technologies and practices reported by POTW.
    We reviewed these data sources for information on add-on control 
technologies, other treatment units, work practices, procedures, and 
process changes or pollution prevention alternatives that were not 
considered during the development of the POTW NESHAP. We also looked 
for information on improvements in add-on control technology, other 
treatment units, work practices, procedures, and process changes or 
pollution prevention alternatives that have occurred since development 
of the POTW NEHSAP. Regarding work practices or pollution prevention 
alternatives, we examined data provided by the POTW in the 2015 ICR for 
the POTW NESHAP related to the pretreatment programs they implement.
    As found during the development of the POTW NESHAP, there are 
generally two different control options that may be used at POTW: 
pretreatment programs and add-on controls (i.e., covers or covers 
vented to a control device). The following sections summarize our 
technology review with respect to these work practices and controls as 
they can be used at industrial (Group 1) POTW and non-industrial (Group 
2) POTW. (See section IV.D.2 of this preamble for a discussion of the 
proposed terminology change from ``industrial'' and ``non-industrial'' 
POTW to ``Group 1'' and ``Group 2'' POTW.)
1. Pretreatment Requirements
    The applicability of the 2002 POTW NESHAP to a particular POTW 
depends in part on whether the POTW has or is required to develop a 
pretreatment program. However, we are proposing to remove having a 
pretreatment program as a condition for the applicability of the NESHAP 
and make it a requirement of the NESHAP. See section IV.D.1 of this 
preamble for a discussion of these changes. This section describes the

[[Page 95374]]

inclusion of pretreatment requirements as a requirement of the rule.
    In the 2015 ICR for the POTW NESHAP, the EPA requested data related 
to any pretreatment programs the POTW had developed and implemented. 
All 17 of the POTW that responded to the ICR included information about 
their specific pretreatment programs, and all six of the sources 
subject to the POTW NESHAP have pretreatment requirements established 
for all industrial wastewaters they receive. The pretreatment 
requirements established by the POTW are based on the National 
Pretreatment Program, which was developed under the CWA to prevent 
pollutants from being introduced into a POTW that could interfere with 
the operation of the POTW, or could be passed through the treatment 
process and impact the use or disposal of sludge or be discharged to 
surface waters (40 CFR 403.5).
    Under the Pretreatment Program, POTW subject to the requirement to 
develop a pretreatment program must identify their industrial users and 
control, through permits, orders, or other means, the contribution of 
pollutants to the POTW in order to ensure compliance with all national 
pretreatment standards and requirements. The industrial discharger must 
comply with the general requirements and specific prohibitions of EPA's 
regulations at 40 CFR part 403.5, categorical pretreatment standards 
spelled out for industrial categories at 40 CFR Subchapter N--Effluent 
Guidelines and Standards, and specific local limits that must be 
developed in defined circumstances. The specific prohibitions address 
characteristics of the wastewater streams and include specifications 
such as flashpoint, pH, solids size (to avoid obstructions), flowrates, 
and temperature of the wastewater. The specific prohibitions also 
prohibit ``Pollutants which result in the presence of toxic gases, 
vapors, or fumes within the POTW in a quantity that may cause acute 
worker health and safety problems.'' (40 CFR 403.5(b)(7).) The 
categorical pretreatment standards are specific standards established 
by the EPA for certain industries. These standards vary in format and 
can be concentration-based limits, mass limits, production-based 
limits, best management practices, discharge prohibitions, or a 
combination of these formats. There are 35 different industries with 
established categorical pretreatment standards. The third component in 
the pretreatment requirements consists of the local limits that must be 
established by the POTW in the circumstances spelled out in the 
regulations. Local limits may need to be developed to address specific 
concerns of the POTW, related to the general and specific prohibitions. 
In addition to ensuring that industrial users' discharges to the POTW 
do not pass through the POTW and result in the violation of the POTW's 
discharge permit, such limits may be necessary in the following 
circumstances: to protect the POTW operations, maintain the POTW's 
discharge levels, avoid sludge contamination, and ensure worker health 
and safety. The local limits may be expressed as case-by-case discharge 
limits, management practices, or specific prohibitions.
    In this action, we are proposing that POTW develop and implement a 
pretreatment program as specified in 40 CFR part 403 (General 
Pretreatment Regulations for Existing and New Sources of Pollution). 
CAA section 112(n)(3) provides that the EPA may include pretreatment 
requirements as a control requirement when establishing standards for 
POTW under CAA section 112, stating: ``When promulgating any standard 
under this section applicable to publicly owned treatment works, the 
Administrator may provide for control measures that include 
pretreatment of discharges causing emissions of hazardous air 
pollutants and process or product substitutions or limitations that may 
be effective in reducing such emissions.'' We are proposing to add 
pretreatment requirements in this rulemaking because pretreatment will 
reduce HAP emissions from both the collection systems and the POTW 
treatment plant operations (including both primary and secondary 
treatment) by limiting the quantity of HAP in the wastewater before it 
is even discharged to the collection system or arrives at the POTW 
treatment plant. This requirement is consistent with CAA section 
112(n)(3) and will serve to reduce pollutant loading into the POTW 
which will reduce emissions throughout all stages of treatment.
    Adding this pretreatment requirement to the POTW NESHAP will not 
add any additional required actions or increase costs or burden for the 
POTW because all of the POTW that are currently subject to this rule 
have established pretreatment programs under the CWA; however, it will 
ensure that pretreatment is appropriately associated to HAP reduction 
requirements and remains in effect even if changes occur in CWA 
regulations. The pretreatment requirements are being applied to both 
industrial (Group 1) and non-industrial (Group 2) POTW for existing and 
new or reconstructed POTW.
    We are requesting comment on the option of having an additional 
requirement that applicable POTW specifically evaluate the volatile 
organic HAP specific to each applicable industrial user because organic 
HAP that volatilize readily are most likely to result in air emissions 
from the water as it moves through a collection system and the POTW 
treatment plant. Because the CWA's National Pretreatment Program does 
not traditionally address air emissions, we understand that the 
existing pretreatment requirements for each industrial user do not 
necessarily reduce HAP emissions. Therefore, we are requesting comment 
on requiring POTW to develop pretreatment requirements that are 
specifically designed to reduce HAP emissions from POTW by requiring 
the POTW to evaluate and set local limits for volatile organic HAP. We 
are also requesting comment on any specific controls or operational 
practices that can be required to address VOC and HAP emissions from 
collection systems. Additionally, we are requesting comment on ways to 
harmonize the pretreatment programs as a means to meet both CAA and CWA 
requirements.
2. Industrial (Group 1) POTW
    Industrial (Group 1) POTW are those POTW that receive a wastewater 
stream that is subject to control under another NESHAP and the 
treatment and controls at the POTW are used to comply with the other 
NESHAP requirements. We are changing the name of the subcategory in 
this action, which is discussed in more detail in section IV.D of this 
preamble. As discussed in section II.B.1 of this preamble, the 2002 
requirements for industrial (Group 1) POTW are different for existing 
and new or reconstructed sources.
    Existing industrial (Group 1) sources. At the time the 2002 NESHAP 
was prepared, there were no known industrial (Group 1) POTW in 
existence because the compliance dates for most of the NESHAP had not 
occurred yet. As a result of this technology review, two industrial 
(Group 1) POTW have been identified that are existing sources under the 
rule. As required, these POTW comply with the wastewater treatment 
requirements as specified in the other applicable NESHAP for which they 
act as control.
    In reviewing the requirements for existing industrial (Group 1) 
POTW and the situations at these sources, we have identified an issue 
with the 2002 NESHAP requirements that could affect existing industrial 
(Group 1) POTW,

[[Page 95375]]

especially considering the new requirements being proposed for existing 
industrial (Group 1) and non-industrial (Group 2) POTW (see section 
IV.C.3 of this preamble). The two identified existing industrial (Group 
1) POTW receive wastewater from several other industrial users at their 
primary treatment units, in addition to the wastewater received that is 
regulated by another NESHAP. Because an existing industrial (Group 1) 
POTW is currently only required to comply with the other applicable 
NESHAP, the requirements under the POTW NESHAP for primary treatment 
units at the POTW treatment plant do not currently apply. One of the 
identified existing industrial (Group 1) POTW receives wastewater from 
a pulp and paper plant, subject to 40 CFR part 63, subpart S (National 
Emission Standards of Hazardous Air Pollutants from the Pulp and Paper 
Industry). The subpart S wastewater is hard piped to the industrial 
(Group 1) POTW and is introduced into the biological treatment unit at 
the industrial (Group 1) POTW, as specified in 40 CFR 63.446(e)(2). 
Because the biological treatment unit is considered secondary 
treatment, there are no NESHAP requirements on the primary treatment 
units at this POTW. The wastewater streams entering the primary 
treatment units are not specifically regulated by another NESHAP. In 
this situation, the primary treatment units are an uncontrolled HAP 
emissions source even though the POTW is an industrial (Group 1) POTW 
and subject to another NESHAP.
    Therefore, we are proposing to revise the requirements for an 
existing industrial (Group 1) POTW so that the POTW must comply with 
both the requirements for existing non-industrial (Group 2) POTW (see 
section IV.C.3 of this preamble) and the other applicable NESHAP. This 
proposed revision to the standards ensures that the primary treatment 
units are still subject to requirements, regardless of where the other 
NESHAP wastewater stream initially enters the POTW treatment plant for 
treatment. We believe all of the existing industrial (Group 1) POTW can 
meet the proposed requirements for existing non-industrial (Group 2) 
sources, and would, therefore, incur minimal cost burden associated 
with recordkeeping and reporting as described in section IV.D.5 of this 
preamble.
    New or reconstructed industrial (Group 1) sources. At the time the 
2002 NESHAP was prepared, we anticipated one new industrial (Group 1) 
POTW would become subject to the regulation. However, during this 
review we did not identify any new or reconstructed industrial (Group 
1) POTW. During our review of the requirements for the existing 
industrial (Group 1) POTW, we identified an issue that could affect new 
industrial (Group 1) POTW. The issue is with the requirement in the 
2002 rule that specifies that the source should meet the most stringent 
requirements of either the other applicable NESHAP, or the requirements 
for new or reconstructed non-industrial (Group 2) POTW in the POTW 
NESHAP (i.e., cover primary treatment units and route emissions to a 
control device; or meet 0.014 HAP fraction emitted limit). Similar to 
the issue identified for existing industrial (Group 1) POTW, we found 
that an industrial (Group 1) POTW could send wastewater regulated by 
another NESHAP directly to a secondary treatment unit, resulting in no 
overlapping requirements between the other NESHAP requirements and the 
new or reconstructed source non-industrial (Group 2) POTW NESHAP 
requirements, which only apply to primary treatment units. Therefore, 
requiring the source to comply with the provision that is the most 
stringent could be confusing, and is potentially difficult to determine 
because non-POTW NESHAP requirements could apply to secondary treatment 
units only and not affect primary treatment units. We considered 
various other possible applicable NESHAP and the requirements in those 
NESHAP and decided that similar inconsistencies could occur with other 
applicable NESHAP. In some cases, it is possible that the requirement 
to comply with the most stringent NESHAP could be read to allow a 
source to inappropriately avoid compliance with one of the applicable 
NESHAP, since the demonstration of most stringent is not clear, not 
obvious, or not well defined.
    Therefore, we are proposing to remove the requirement to comply 
with the most stringent NESHAP and are revising the requirement for new 
or reconstructed industrial (Group 1) POTW to require the POTW to meet 
the requirements of both the other applicable NESHAP, and the 
requirements of the POTW NESHAP. Meeting the requirements of both the 
other applicable NESHAP and the POTW NESHAP makes the rule clearer and 
more consistent with the standards in other applicable NESHAP and the 
POTW NESHAP.
3. Non-Industrial (Group 2) POTW
    In the 2002 regulation, non-industrial (Group 2) POTW are those 
POTW that receive wastewater from industrial users but do not receive 
any wastewater streams that must be controlled pursuant to another 
NESHAP. In this action, we are changing this terminology as discussed 
in more detail in section IV.D of this preamble. As discussed in 
section II.B.4 of this preamble, requirements for non-industrial (Group 
2) POTW are different for existing and new or reconstructed sources.
    Existing non-industrial (Group 2) sources. During our review, four 
existing non-industrial (Group 2) POTW were identified. Treatment units 
at POTW can be covered, which suppresses the volatilization of HAP, 
keeping the HAP in the water and preventing emissions to the air. Also, 
covered units can be vented and, if vented, emissions are either routed 
to the atmosphere or a control device. The use of covers and controls 
has increased since the initial development of the POTW NESHAP. For 
example, in the original review for development of the 2002 rule, there 
was only one POTW that had covers on all primary treatment units. Other 
than grate covers (which do not control emissions and which we do not 
consider to be ``covers'' as we are using that term), no other covers 
were identified during the initial development of the 2002 rule. During 
this review, we found two POTW subject to the POTW NESHAP that cover 
all treatment units to address odor concerns. Also, more POTW now have 
at least some treatment units covered. There are two POTW subject to 
this rule that do not have covers on any treatment units.
    When vented to an add-on control device, the exhaust stream from 
under a cover may be routed to a caustic scrubber, a carbon adsorber, 
or to a secondary wastewater treatment unit such as an aeration basin 
where the exhaust stream is used as feed air for biological treatment. 
Add-on control devices such as caustic scrubbers and carbon adsorbers 
are typically used at POTW treatment plants to control odors. While 
caustic scrubbers are not expected to be effective in controlling 
volatile HAP, properly designed and operated carbon adsorbers are 
commonly used in other industries to control volatile organic compounds 
(VOC) and HAP emissions. However, as installed at POTW to assist in 
odor control, carbon adsorbers are not typically designed or operated 
to provide HAP emission reduction.
    Some POTW route collected gases to biological treatment processes 
to control odors, and this technique has been found to reduce emissions 
of HAP. To use biological treatment as a control for HAP emissions, 
treatment units must be covered, and the gases collected under the 
cover must be routed to the

[[Page 95376]]

biological treatment unit. Based on the literature search conducted as 
part of the technology review, biological treatment processes employing 
activated sludge basins can achieve a VOC control efficiency greater 
than 85-percent under certain conditions, and in one case, a pilot-
study biological treatment system employing biofilters was able to 
achieve greater than 99-percent control of certain HAP. Outside of this 
one study, the literature on biological treatment using biofilters 
indicated VOC and HAP control efficiencies of between 40-percent and 
83-percent. The memorandum titled Technology Review Memorandum for the 
Publicly Owned Treatment Works Source Category (Technology Review 
Memo), November 2016 in the docket for this action presents the 
literature review and information found on biological treatment 
systems.
    Detailed ICR responses regarding the use of control measures to 
control HAP were received for four POTW subject to the POTW NESHAP and 
eight synthetic area or area sources. For these 12 sources, all except 
two sources route some portion of emissions to caustic scrubbers, 
caustic scrubbers followed by carbon adsorbers (2-stage control), or 
route gases to biological treatment. However, covers are not used 
consistently throughout the POTW; only the two POTW subject to the POTW 
NESHAP mentioned previously cover all their processes and collect all 
gases and route those gases to controls. These two POTW use covers and 
controls to address concerns related to odor. They do not specifically 
operate the controls to reduce HAP emissions and do not have any data 
specific to HAP reductions that could be achieved by the controls they 
currently use. Several other POTW were found to use partial covers and 
send some emissions to controls. Two other POTW subject to the POTW 
NESHAP and six out of eight area sources indicated the use of add-on 
control devices and several reported routing gases to biological 
treatment, but not all of the HAP emissions would be captured and 
controlled for these sources, because not all the treatment units are 
covered at these POTW. Also, of the 12 facilities that responded to the 
ICR, only three sources (all area sources operated by the City of San 
Diego) claimed any HAP reduction from their odor control devices. No 
indication of the VOC or HAP control efficiency for these three 
facilities was available. Responses to the 2015 ICR are located in the 
docket. See Information Collection and Additional Data Received for the 
Publicly Owned Treatment Works Source Category Risk and Technology 
Review, October 2016 located in the docket for this rulemaking.
    In this action, the EPA is soliciting comments on the effectiveness 
of caustic scrubbers and carbon adsorbers to co-control HAP while 
primarily functioning as odor control devices. In addition, the EPA is 
requesting quantitative feedback on the effectiveness of using covers 
to suppress emissions, and identification of any other key operating 
parameters that may affect HAP emissions levels such as ventilation 
rates or control device maintenance practices.
    In addition to an evaluation of the use of covers and controls to 
reduce HAP emissions, the EPA evaluated the HAP fraction emitted up to, 
but not including, secondary treatment. Data were available for two of 
the non-industrial (Group 2) POTW, and their HAP fractions were 0.04 
and 0.03. Additionally, since we are proposing that existing industrial 
(Group 1) POTW must comply with both the other applicable NESHAP and 
the HAP fraction emitted standard in the POTW NESHAP, we evaluated 
available primary treatment emissions data for one of the existing 
industrial (Group 1) POTW. The primary treatment units at that POTW are 
not currently subject to regulation under another NESHAP; therefore, 
the emissions from primary treatment units at that industrial (Group 1) 
POTW are comparable to emissions from primary treatment units at the 
non-industrial (Group 2) POTW. That industrial (Group 1) POTW has a HAP 
fraction of 0.005. See HAP Emissions from the Publicly Owned Treatment 
Works Source Category, November 2016 located in the docket for this 
rulemaking.
    These HAP fractions are lower than the HAP fraction found for the 
sources investigated during the development of the 2002 POTW NESHAP. At 
that time, the average HAP fraction of the six POTW thought to be major 
sources was 0.166. The available data for this proposal provides an 
average HAP fraction of 0.0225. However, because of the limited data 
and the fact that these HAP fractions are based on calculations using 
data from a moment in time and do not reflect the variability in 
operation, we are proposing a standard at twice the highest HAP 
fraction for which we have data. Therefore, with this action, we are 
proposing that existing non-industrial (Group 2) POTW must operate with 
an annual rolling average HAP fraction emitted from primary treatment 
units of 0.08 or less. By proposing to require that POTW achieve a HAP 
fraction that is twice the maximum HAP fraction reported by ICR 
respondents, we intend to address variability in wastewater influent 
concentrations and in treatment operations. Moreover, as proposed the 
rule is expected to allow POTW the flexibility to use various control 
schemes, including the use of add-on controls such as scrubbers or 
biological treatment to comply with the standard. At the same time, 
because the risk analysis for allowable emissions also was assessed at 
twice the level of actual emissions (see section III.A of this 
preamble) the proposed standards should ensure that emissions will not 
exceed the level of acceptable risk found during the risk assessment. 
Also, note that this proposed standard achieves at least the same level 
of protection as a standard based on a MACT floor calculation. See 
Memorandum Providing Calculations for Total HAP Emissions from Publicly 
Owned Treatment Works Wastewater, October 2016, located in the docket 
for this rulemaking.
    We believe that the existing industrial (Group 1) and existing non-
industrial (Group 2) sources identified as subject to this proposed 
rule can meet this HAP fraction emission limit. However, we request 
comment and data on whether this is true for the POTW that would be 
subject to this proposed standard. We are also taking comment on 
whether we should provide an alternative to the 0.08 HAP fraction 
emitted for existing non-industrial (Group 2) sources. One alternative 
under consideration is to allow POTW to choose to cover the primary 
clarifier instead of meeting the 0.08 HAP fraction emitted standard. 
Data collected in the 2015 ICR indicate that primary clarifiers are the 
largest emission source at the POTW, and several existing sources 
already have covers on their primary clarifiers.
    We also are taking comment on a second alternative that would 
require existing sources to meet the same cover and control 
requirements as new sources by requiring them to cover their primary 
treatment units and to route the air in the headspace from all covered 
units, except the primary clarifier, to a control device via a closed 
vent system. The 2002 POTW NESHAP requires a cover on primary 
clarifiers, but does not require routing the air collected under the 
cover to a control device. When the 2002 POTW NESHAP was developed, 
data from the industry indicated that the only potential major source 
with covers excluded routing air from the covered primary clarifier to 
a control device. A primary clarifier is designed to operate with a 
quiescent surface in order to

[[Page 95377]]

promote the settling of solids. Pulling air could potentially cause 
turbulence on the surface of the water, thus reducing the efficiency of 
the primary clarifier.
    EPA has determined that cover and control of the primary treatment 
units is an expensive option, and believes that the flexibility to 
develop a compliance plan to meet the HAP fraction emitted standard 
will allow subject facilities more latitude to develop a compliance 
approach to meet the HAP fraction standard. However, EPA is aware that 
many current facilities do have a cover and control system in place to 
control odors, and if those systems can be modified or operated in a 
manner to control HAP emissions then this alternative might be viable 
for some existing sources. More details related to the costs of covers 
and controls is located in the Technology Review Memo, located in the 
docket for this rulemaking.
    New or reconstructed non-industrial (Group 2) POTW. There were no 
new or reconstructed non-industrial (Group 2) POTW identified during 
the technology review. Also, there were no new practices or control 
technologies that would warrant a change in the 2002 requirements for 
new or reconstructed non-industrial (Group 2) POTW. Thus, we are not 
proposing any changes in the standard for new or reconstructed non-
industrial (Group 2) POTW as a result of this technology review.

D. What other actions are we proposing?

    In addition to the proposed actions described above, we are 
proposing additional revisions. We are proposing to revise the 
applicability criteria to clear up confusion related to what emission 
sources are included in the major source calculations and to remove the 
applicability condition that affected sources must have a pretreatment 
program. We are also proposing to revise the subcategory names and 
definitions to further clarify the difference between them. We are 
proposing revisions to the startup, shutdown, and malfunction (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 CAA section 112(d) 
emission standards during periods of SSM. We are also proposing 
electronic reporting for certain records. Finally, we are proposing 
various other technical corrections. Our analyses and proposed changes 
related to these issues are presented below.
1. Applicability Criteria
    There are currently three criteria that a POTW must meet in order 
to be subject to the POTW NESHAP: (1) You must own or operate a POTW 
that includes a POTW treatment plant; (2) your POTW is a major source 
of HAP emissions or any industrial (Group 1) POTW regardless of whether 
or not it is a major source of HAP emissions; and (3) your POTW is 
required to develop and implement a pretreatment program as defined by 
40 CFR 403.8.
    The EPA is proposing to revise the first and second applicability 
criteria in order to clarify the original intent of the rule by 
revising 40 CFR 63.1580(a)(1) and (2) to state, ``(1) You own or 
operate a POTW that is a major source of HAP emissions; or (2) you own 
or operate a Group 1 POTW regardless of whether or not it is a major 
source of HAP.'' See section IV.D.2 of this preamble for proposed 
revisions to the subcategory names.
    We are proposing this change because during our review of the 2002 
POTW NESHAP, we found several instances where a POTW might not realize 
they are subject to the standards, or where the applicability criteria 
could be misinterpreted, thus being read as excluding facilities that 
should be covered by this NESHAP. In addition, several EPA regional 
offices expressed concerns that POTW were underrepresenting their HAP 
emissions and raised questions about whether emissions from equipment 
comprising the collection systems should be included in those 
calculations. For instance, one region discussed obtaining measurements 
of high concentrations of benzene and VOC from perforated manhole 
covers. Upon further inspection, the elevated readings were attributed 
to an industrial user that was discharging pretreated wastewater into 
the collection system for treatment at a nearby POTW. However, that 
POTW was not accounting for emissions from collection systems and, to 
their knowledge, had not exceeded the major source threshold. In 
another region, a pump station located outside the POTW treatment plant 
had potential emissions that would exceed the major source threshold. 
However, because these emissions were not part of the POTW treatment 
plant, they had not been previously considered when determining whether 
the POTW was a major source of HAP emissions.
    The 2002 applicability criteria in 40 CFR 63.1580(a)(2) state that 
it is the emissions from the entire POTW, not just the POTW treatment 
plant, that must be considered when determining whether the POTW is a 
major source. Further, this same provision states that any 
``industrial'' (Group 1) POTW, which treats a wastewater stream which 
is regulated by another NESHAP or MACT, is subject to the rule whether 
or not it is a major source of HAP. The EPA recognizes that the current 
wording may cause confusion regarding what emissions sources must be 
included in the calculation and is proposing revisions to avoid such 
confusion.
    The EPA is also proposing to revise the third applicability 
criterion in order to clarify the original intent of the rule by 
revising 40 CFR 63.1580(a) to state, ``You are subject to this subpart 
if your publicly owned treatment works (POTW) has a design capacity to 
treat at least 5 million gallons of wastewater per day and treats 
wastewater from an industrial user, and either paragraph (a)(1) or 
(a)(2) is true:.'' This proposed revision removes the requirement that 
a POTW develop and implement a pretreatment program from the 
applicability criteria, and instead clarifies the original intent of 
the rule, which is to limit applicability to POTW which treat at least 
5 MGD.
    The EPA also identified a potential scenario that could 
inadvertently allow major source POTW to avoid applicability to the 
rule based on the current third criteria. The 2002 POTW NESHAP states 
that in order to be subject to the rule, the POTW must be required to 
develop and implement a pretreatment program (40 CFR 63.1580(a)(3)). 
During review, we identified a potential scenario where a POTW is a 
major source of HAP emissions, but is not required to develop a 
pretreatment program by the EPA or state pretreatment program Approval 
Authority. In this scenario, the POTW might interpret the third 
criterion as not applying to them. For instance, 40 CFR 403.10(e) 
allows a state to assume responsibility for implementing the POTW 
Pretreatment Program requirements set forth in 403.8(f) in lieu of 
requiring the POTW to develop a POTW. Only five states have used their 
authority under this provision (Connecticut, Vermont, Alabama, 
Mississippi, and Nebraska). Similarly, other approved State Programs 
which implement their State Pretreatment Program traditionally by 
approving POTW pretreatment program development must also have 
procedures to carry out the activities set for in 403.8(f) in the 
absence of a POTW Pretreatment Program. However, the third 
applicability criterion in the 2002 POTW NESHAP was not intended to 
exclude POTW where states or the EPA, in the absence of a POTW approved

[[Page 95378]]

Pretreatment Program or a state approved pretreatment program, directly 
oversee the industrial pretreatment requirements. Instead, the EPA 
stated in the response to comments from the previous rulemaking \27\ 
that the Agency added the third applicability criterion to the final 
rule to limit applicability to those POTW that are required to develop 
and implement a pretreatment program in order to eliminate all POTW 
with a total design flow less than 5 MGD because it was not likely that 
a small POTW would have sufficient emissions to trigger major source 
status. The EPA continues to believe that small POTW that do not 
trigger major source status should be excluded from the requirements in 
the POTW NESHAP.
---------------------------------------------------------------------------

    \27\ See National Emission Standards for Hazardous Air 
Pollutants (NESHAP): Publicly Owned Treatment Works--Background 
Information for Final Standards Summary of Public Comments and 
Responses. EPA-453/R-99-008 October 1999.
---------------------------------------------------------------------------

    We are proposing to revise the criteria to include POTW that have a 
design capacity of 5 MGD or greater and that treat wastewater from 
industrial users. These are equivalent criteria for which POTW are 
required to develop and implement pretreatment programs as defined in 
40 CFR 403.8. However, by not stating that the ``POTW is required to 
develop or implement,'' we are clarifying that any POTW that is a major 
source of HAP emissions and meets the general requirements for the 
development of a pretreatment program is subject to the proposed rule, 
regardless of whether the state has implemented its own pretreatment 
program under 40 CFR 403.10(e).
    It is not our intent that the requirements apply to small POTW that 
are not a major source of HAP emissions. Therefore, we are requesting 
comment on whether these proposed revisions to the applicability 
criteria inadvertently include POTW that would otherwise have not been 
included in a major source rule or inadvertently exclude sources that 
should be covered because they are a Group 1 POTW or are a major source 
of HAP emissions. Finally, we are requesting comment on whether there 
is a more appropriate design capacity threshold than the 5 MGD 
threshold proposed in this rulemaking.
2. Definitions of Subcategories
    The EPA is proposing to revise the names and definitions for the 
subcategories identified in the POTW NESHAP in order to clear up any 
confusion related to applicability of the rule. The POTW NESHAP has 
historically subcategorized requirements based on whether or not a POTW 
is used as a control device to comply with specific requirements in 
another source category's NESHAP by classifying a POTW as either an 
``industrial POTW treatment plant'' or ``non-industrial POTW treatment 
plant'' (40 CFR 63.1581). The 1998 proposal described how the EPA 
determined these subcategories for the POTW source category by stating 
that ``the industrial POTW treatment plant subcategory would include 
only those POTW treatment plants that are treating a specific regulated 
industrial waste stream to allow an industrial user to comply with 
another NESHAP'' (63 FR 66089). We further explained that any POTW not 
in the industrial POTW treatment plant subcategory would be classified 
as a non-industrial POTW treatment plant, which accepts waste from 
industrial users whose waste is not specifically regulated under 
another NESHAP. While the intent of the subcategorization was explained 
in the 1998 proposal and the terms are defined in the rule (in 40 CFR 
63.1595), there is a potential for confusion related to applicability 
under the subcategories because the terms ``industrial'' and ``non-
industrial'' have common, everyday meanings that are not exactly 
aligned with how those terms are defined in the rule. For example, a 
person might incorrectly assume that the term ``industrial POTW'' 
includes any POTW that accepts waste from an industrial user, even if 
the industrial user is not subject to another NESHAP, and that a ``non-
industrial POTW'' is one that does not take any waste from any 
industrial users.
    To clear up this confusion, we are proposing to change the names 
and definitions of the subcategories in the POTW source category. A 
``Group 1 POTW treatment plant'' is one that accepts a waste stream(s) 
regulated under another NESHAP from an industrial user for treatment. 
In this instance, the POTW acts as the control mechanism by which the 
industrial user is able to comply with the specific requirements for 
that waste stream in the other NESHAP. For example, a pulp mill may 
choose to send a waste stream regulated by 40 CFR part 63, subpart S 
(Pulp and Paper Industry NESHAP) to a local POTW for treatment in lieu 
of constructing an onsite wastewater treatment facility to comply with 
the requirements of subpart S. In this example, the POTW is in a 
contractual agreement with the pulp mill that the POTW will meet the 
specific requirements for that waste stream and becomes subject to the 
Pulp and Paper Industry NESHAP in addition to the POTW NESHAP. A Group 
1 POTW treatment plant does not have to have HAP emissions in excess of 
the major source threshold but is instead considered subject to this 
proposed rule because it is also subject to requirements in another 
NESHAP. If the Group 1 POTW treatment plant accepts multiple waste 
streams that are regulated under multiple NESHAP, we are proposing that 
the POTW would meet the requirements of each appropriate NESHAP for 
each individual waste stream.
    A ``Group 2 POTW treatment plant'' is one that accepts a waste 
stream(s) that is not specifically regulated by another NESHAP or one 
that accepts wastewater from an industrial facility that complies with 
the specific wastewater requirements in their applicable NESHAP prior 
to discharging the wastewater to the POTW collection system. These 
waste streams can come from an industrial or commercial source. For 
example, a chemical plant sends a waste stream to a POTW that is not 
regulated by any of the chemical manufacturing source categories for 
treatment as a permitted discharge through the POTW's pretreatment 
program. In most cases, these waste streams are pretreated at the 
industrial facility in order to meet specific water quality 
requirements issued by the POTW through a Significant Industrial User 
(SIU) permit. Pretreatment programs are discussed in section IV.C.1 of 
this preamble.
    The EPA is proposing the ``Group 1'' and ``Group 2'' names rather 
than a new pair of descriptive names because (1) the non-descriptive 
names ``Group 1'' and ``Group 2'' will alert persons to the fact that 
they need to look to the specific definitions of the subcategories in 
the rule, and (2) we could not identify any descriptive names that did 
not create the potential for confusion similar to the current 
``industrial'' and ``non-industrial'' labels. The EPA requests ideas 
for descriptive names for the two subcategories that would not create a 
potential for confusion.
3. Startup, Shutdown, and Malfunction
    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008), the United States Court of Appeals for the District of 
Columbia Circuit vacated portions of two provisions in the EPA's CAA 
section 112 regulations governing the emissions of HAP during periods 
of SSM. Specifically, the Court vacated the SSM exemption contained in 
40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), holding that under section 
302(k) of the CAA, emissions standards or limitations must

[[Page 95379]]

be continuous in nature and that the SSM exemption violates the CAA's 
requirement that some CAA section 112 standards apply continuously.
    We are proposing the elimination of the SSM exemption in this rule. 
Consistent with Sierra Club v. EPA, we are proposing standards in this 
rule that apply at all times. We are also proposing several revisions 
to Table 1 to Subpart VVV of Part 63 (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 developing the standards in this rule, the EPA has taken into 
account startup and shutdown periods and has not proposed alternate 
standards for those periods. Periods of startup and shutdown at POTW 
are highly infrequent events. At all times, a plant subject to 40 CFR 
part 63, subpart VVV must comply with the pretreatment requirements and 
either the cover and closed vent system standard or the HAP fraction 
emissions standard.
    For pretreatment requirements, startup and shutdown at the POTW do 
not impact the effect of pretreatment requirements, because these 
require POTW to apply pretreatment standards on the industrial users. 
The industrial users meet these standards before the wastewater enters 
the collection system of the POTW and so those industrial users' 
ability to meet the pretreatment requirements is not dependent on the 
operational status of the POTW.
    For compliance using covers and closed vent systems routed to a 
control device, startup and shutdown of the POTW does not affect 
performance of the control device. The control system can and must be 
operated when wastewater first enters the system. In the unlikely event 
of shutdown of the POTW, the control system must be operated until the 
final wastewaters are treated. Because the physical and chemical 
characteristic of the gases in the closed vent system are not 
sufficiently different during startup and shutdown, the emission 
control system will achieve the same level of emission control that it 
achieves during normal operation. Therefore, there is no need for an 
alternative standard during startup and shutdown that is different from 
the standards for normal operation.
    It is possible that control devices (e.g., flares, carbon 
absorbers, or scrubbers) that receive emissions through the closed vent 
systems could have startup and shutdown events. This equipment must 
meet the requirements of 40 CFR part 63, subpart DD (because DD is 
incorporated by reference into subpart VVV). Subpart DD requires that 
control devices are operating to fully control emissions when emissions 
are routed to them, as specified in 40 CFR 63.693 of subpart DD, except 
for a limited number of hours per year for routine maintenance for 
control devices controlling tank emissions (40 CFR 63.693(b)(3)).
    For compliance using the alternative HAP fraction emissions 
standard, compliance may be achieved by a combination of a cover and 
closed vent system to a control device, a biological treatment phase, 
pretreatment, or modifications to the wastewater treatment process. The 
covers, closed vents, and the range of potential control devices would 
all be available throughout startup and shutdown of the POTW. 
Therefore, we do not expect there to be any significant difference in 
the emissions due to a startup or shutdown. In addition, compliance 
with the HAP fraction emissions standard is demonstrated based on a 12-
month rolling average. Because the averaging period is annual, any 
increases in the HAP fraction emitted that do occur during startup or 
shutdown periods (which are short), can easily be balanced by the 
longer periods of normal operation and lower HAP fraction emitted 
during the rest of the averaging period.
    Periods of startup, normal operations, and shutdown are all 
predictable and routine aspects of a source's operations. Malfunctions, 
in contrast, are neither predictable nor routine. Instead, they are, by 
definition, sudden, infrequent and not reasonably preventable failures 
of emissions control, process, or monitoring equipment. (See 40 CFR 
63.2, definition of Malfunction). The EPA interprets CAA section 112 as 
not requiring emissions that occur during periods of malfunction to be 
factored into development of CAA section 112 standards. Under CAA 
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 sources when 
setting emission standards. As the District of Columbia Circuit Court 
has recognized, the phrase ``average emissions limitation achieved by 
the best performing 12 percent of'' sources ``says nothing about how 
the performance of the best units is to be calculated.'' Nat'l Ass'n of 
Clean Water Agencies v. EPA, 734 F.3d 1115, 1141 (D.C. Cir. 2013). 
While the EPA accounts for variability in setting emissions standards, 
nothing in CAA section 112 requires the Agency to consider malfunctions 
as part of that analysis. A malfunction should not be treated in the 
same manner as the type of variation in performance that occurs during 
routine operations of a source. A malfunction is a failure of the 
source to perform in a ``normal or usual manner'' and no statutory 
language compels the EPA to consider such events in setting CAA section 
112 standards.
    Further, accounting for malfunctions in setting emission standards 
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, emissions during a 
malfunction event can be significantly higher than emissions at any 
other time of source operation. For example, if an air pollution 
control

[[Page 95380]]

device with 99-percent removal goes off-line as a result of a 
malfunction (as might happen if, for example, the bags in a baghouse 
catch fire) and the emission unit is a steady state type unit that 
would take days to shut down, the source would go from 99-percent 
control to zero control until the control device was repaired. The 
source's emissions during the malfunction would be 100 times higher 
than during normal operations. As such, the emissions over a 4-day 
malfunction period would exceed the annual emissions of the source 
during normal operations. As this example illustrates, accounting for 
malfunctions could lead to standards that are not reflective of (and 
significantly less stringent than) levels that are achieved by a well-
performing non-malfunctioning source. It is reasonable to interpret CAA 
section 112 to avoid such a result. The EPA's approach to malfunctions 
is consistent with CAA section 112 and is a reasonable interpretation 
of the statute.
    Similar to startup and shutdown events, malfunctions of the POTW do 
not impact the effect of pretreatment requirements, because these 
require POTW to apply pretreatment standards on the industrial users. 
The industrial users meet these standards before the wastewater enters 
the collection system of the POTW.
    In the case of a POTW that uses covers, closed vent systems, and 
control devices, the covers and closed vents are typically constructed 
without moving parts and are frequently permanent structures made of 
concrete. While malfunctions are theoretically possible, the EPA found 
no information from affected facilities that malfunctions have actually 
happened in such systems.
    The control devices used to comply with the standards in 40 CFR 
part 63, subpart VVV are subject to the control device standards in 40 
CFR part 63, subpart DD (because subpart DD is incorporated by 
reference into subpart VVV). A malfunction of control devices that are 
subject to subpart DD that results in a failure to meet a standard 
would be subject to the excess emissions recordkeeping and reporting 
requirements for the relevant device under subpart DD.
    For POTW that are complying with the HAP fraction emissions 
alternative standard, the standard is an annual rolling average of the 
HAP fraction emitted. A malfunction event at a facility that is 
properly maintained and operated is likely to result in only a small 
and short-term increase in emissions that is unlikely to cause an 
exceedance of the annual standard. In the event that a malfunction 
causes an exceedance, the facility would report the nature of the 
malfunction in the excess emission report.
    In the unlikely 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).
    If the EPA determines in a particular case that an enforcement 
action against a source for violation of an emission standard is 
warranted, the source can raise any and all defenses in that 
enforcement action and the Federal District Court will determine what, 
if any, relief is appropriate. The same is true for citizen enforcement 
actions. Similarly, the presiding officer in an administrative 
proceeding can consider any defense raised and determine whether 
administrative penalties are appropriate.
    In summary, the EPA interpretation of the CAA and, in particular, 
CAA section 112 is reasonable and encourages practices that will avoid 
malfunctions. Administrative and judicial procedures for addressing 
exceedances of the standards fully recognize that violations may occur 
despite good faith efforts to comply and can accommodate those 
situations.
    The EPA is proposing changes to the SSM provisions of 40 CFR part 
63, subpart VVV to comport with the Sierra Club court ruling and 
harmonize with certain provisions of 40 CFR part 63, subpart DD. 
Subpart VVV incorporates some requirements of subpart DD by reference. 
In 2015 (see 80 FR 14248), the SSM provisions of subpart DD were 
revised. The changes proposed here for the SSM provisions in subpart 
VVV are congruent to the changes already promulgated under subpart DD. 
This section describes how we propose to revise subpart VVV to 
harmonize with the SSM changes that have already been promulgated in 
subpart DD.
a. 40 CFR 63.1583 and 63.1586 General Duty
    We are proposing to revise the General Provisions Table, Table 1 to 
Subpart VVV of part 63, (hereafter referred to as Table 1) entry for 40 
CFR 63.6(e)(1)(i) by changing the ``yes'' in column 2 to a ``no.'' 
Section 63.6(e)(1)(i) describes the general duty to minimize emissions. 
Some of the language in that section is no longer necessary or 
appropriate in light of the elimination of the SSM exemption. We are 
proposing instead to add general duty regulatory text at 40 CFR 
63.1583(d) and 63.1586(e) that reflects the general duty to minimize 
emissions while eliminating the reference to periods covered by an SSM 
exemption in Table 1. 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 63.1583(d) and 63.1586(e) does not include that 
language from 40 CFR 63.6(e)(1).
    We are also proposing to revise Table 1 by adding an entry for 40 
CFR 63.6(e)(1)(ii) and designating in column 2 that it does not apply 
with a ``no.'' Section 63.6(e)(1)(ii) imposes requirements that are not 
necessary with the elimination of the SSM exemption or are redundant 
with the general duty requirement being added at 40 CFR 63.1583(d) and 
63.1586(e).
b. SSM Plan
    We are proposing to revise Table 1 by adding an entry for 40 CFR 
63.6(e)(3) and designating that it does not apply. 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.
c. Compliance With Standards
    We are proposing to revise table 1 by adding an entry for 40 CFR 
63.6(f)(1) and designating that it does not apply. 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 CAA section 112 standards apply

[[Page 95381]]

continuously. Consistent with Sierra Club, the EPA is proposing to 
revise standards in this rule to apply at all times.
    We are proposing to leave unchanged the Table 1 entry for 40 CFR 
63.6(h) because the existing rule indicated that opacity standards are 
not applicable. The current language of 40 CFR 63.6(h)(1) exempts 
sources from opacity standards during periods of SSM. Generally, POTW 
do not have visible emissions.
d. 40 CFR 63.1590 Performance Testing
    We are proposing to revise the Table 1 entry for 40 CFR 63.7(e)(1) 
by changing the ``yes'' in column 2 to a ``no.'' Section 63.7(e)(1) 
describes performance testing requirements. The EPA is instead 
proposing to revise the language used to incorporate the performance 
testing requirements at 40 CFR 63.694, the performance testing 
provisions for control devices in 40 CFR part 63, subpart DD. The 
performance testing requirements in subpart DD differ from the General 
Provisions performance testing provisions in several respects. The 
performance testing provisions in 40 CFR 63.694(l) of subpart DD 
(incorporated by reference) provide that performance tests be based on 
representative performance (i.e., performance based on normal operating 
conditions) and exclude periods of startup and shutdown unless 
specified by the Administrator. And 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 often 
not representative of normal operating conditions. The EPA is proposing 
to revise the language incorporating those sections of subpart DD that 
require the owner or operator to record the process information that is 
necessary to document operating conditions during the test and include 
in such record an explanation to support that such conditions represent 
normal operation. Section 63.7(e) requires that the owner or operator 
make available to the Administrator such records ``as may be necessary 
to determine the condition of the performance test'' available to the 
Administrator upon request, but does not specifically require the 
information to be recorded. The regulatory text the EPA is proposing to 
incorporate builds on that requirement and makes explicit the 
requirement to record the information.
e. Monitoring
    We are proposing to revise the table 1 entry for 40 CFR 63.8 by 
adding specific table entries for 63.8(c)(1)(i) and (iii) and 
indicating ``no'' in column 2. 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)).
    We are proposing to revise Table 1 by adding an entry for 40 CFR 
63.8(d)(3) and indicating ``no'' in column 2. The final sentence in 40 
CFR 63.8(d)(3) refers to the General Provisions' SSM plan requirement 
which is no longer applicable. The EPA is proposing to add language to 
Table 1 that is identical to 40 CFR 63.8(d)(3), except that the final 
sentence is replaced with the following sentence: ``The program of 
corrective action should be included in the plan required under Sec.  
63.8(d)(2).''
f. 40 CFR 63.1589 Recordkeeping
    We are proposing to revise the Table 1 entry for 40 CFR 
63.10(b)(2)(i) by changing the ``yes'' in column 2 to a ``no.'' Section 
63.10(b)(2)(i) describes the recordkeeping requirements during startup 
and shutdown. These recording provisions are no longer necessary 
because the EPA is proposing that recordkeeping and reporting 
applicable to normal operations will apply to startup and shutdown. In 
the absence of special provisions applicable to startup and shutdown, 
such as a startup and shutdown plan, there is no reason to retain 
additional recordkeeping for startup and shutdown periods.
    We are proposing to revise Table 1 to add an entry for 40 CFR 
63.10(b)(2)(ii) and indicating ``no'' in column 2. Section 
63.10(b)(2)(ii) describes the recordkeeping requirements during a 
malfunction. The EPA is proposing that the requirements of 40 CFR 
63.696(h) and 40 CFR 63.1589(d) be the applicable recordkeeping 
requirements. The regulatory text we are proposing to make applicable 
differs from the General Provisions it is replacing in that the General 
Provisions requires the creation and retention of a record of the 
occurrence and duration of each malfunction of process, air pollution 
control, and monitoring equipment. The EPA is proposing that 40 CFR 
63.696(h) and 40 CFR 63.1589(d) 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 
requirements under 40 CFR 63.696(h) and 40 CFR 63.1589(d) also provide 
that sources keep records that include a list of the affected source or 
equipment and actions taken to minimize emissions, an estimate of the 
quantity of each regulated pollutant emitted over the standard for 
which the source failed to meet the standard, and a description of the 
method used to estimate the emissions. Examples of such methods would 
include product-loss calculations, mass balance calculations, 
measurements when available, or engineering judgment based on known 
process parameters. The EPA is proposing to require that sources keep 
records of this information to ensure that there is adequate 
information to allow the EPA to determine the severity of any failure 
to meet a standard, and to provide data that may document how the 
source met the general duty to minimize emissions when the source has 
failed to meet an applicable standard.
    We are proposing to revise the General Provisions table (Table 1 
entry for 40 CFR 63.10(b)(2)(iv) by changing the ``yes'' in column 2 to 
a ``no.'' When applicable, the provision requires sources to record 
actions taken during SSM events when actions were inconsistent with 
their SSM plan. The requirement is no longer appropriate because SSM 
plans will no longer be required. The requirement previously applicable 
under 40 CFR 63.10(b)(2)(iv)(B) to record actions to minimize emissions 
and record corrective actions is now applicable as a record required by 
40 CFR 63.696(h) and 40 CFR 63.1589(d).
    We are proposing to revise the General Provisions Table 1 entry for 
40 CFR 63.10(b)(2)(v) by adding an entry and indicating ``no'' in 
column 2. When applicable, the provision requires sources to record 
actions taken during SSM events to show that actions taken were 
consistent with their SSM plan. The requirement is no longer 
appropriate because SSM plans will no longer be required.
    We are proposing to revise Table 1 by adding an entry for 40 CFR 
63.10(c)(15) and indicating ``no'' in column 2. The EPA is proposing 
that 40 CFR 63.10(c)(15) no longer apply. When applicable, the 
provision allows an owner or operator to use the affected source's 
startup, shutdown, and malfunction plan or records kept to satisfy the 
recordkeeping requirements of the startup, shutdown, and malfunction 
plan specified in 40 CFR 63.6(e), to also satisfy the requirements of 
40 CFR 63.10(c)(10) through (12). The EPA is proposing to eliminate 
this

[[Page 95382]]

requirement because SSM plans would no longer be required, and 
therefore 40 CFR 63.10(c)(15) no longer serves any useful purpose for 
affected units.
g. 40 CFR 63.1590 Reporting
    We are proposing to revise the Table 1 entry for 40 CFR 63.10(d)(5) 
by adding an entry and indicating ``no'' in column 2. Section 
63.10(d)(5) describes the reporting requirements for startups, 
shutdowns, and malfunctions. Rather than rely on the General Provisions 
reporting requirement, the EPA is proposing that the existing 
incorporation in 40 CFR 63.693 of subpart DD adequately provides for 
reporting of a failure to meet a standard when control devices are 
being used and 40 CFR 63.1590(a) when there is a failure to meet the 
standard when other compliance methods are used. Section 63.693 
requires that sources that fail to meet an applicable standard at any 
time must report the information concerning such events in the semi-
annual report required for affected facilities under 40 CFR 
63.697(b)(3) and (b)(4). The current provisions in subpart DD that we 
are proposing, which apply when control devices are used as the 
compliance measure, state that the report must contain the number, 
date, time, duration, and the cause of such events (including unknown 
cause, if applicable), a list of the affected source or equipment, an 
estimate of the quantity of each regulated pollutant emitted over any 
emission limit, and a description of the method used to estimate the 
emissions. We are proposing a similar report in 40 CFR 63.1590(a) that 
contains the same reporting elements, but applies when another 
compliance measure other than a control device, is used. This report is 
required annually.
    Examples of such methods would include product-loss calculations, 
mass balance calculations, measurements when available, or engineering 
judgment based on known process parameters. The EPA is proposing this 
requirement to ensure that there is adequate information to determine 
compliance, to allow the EPA to determine the severity of the failure 
to meet an applicable standard, and to provide data that may document 
how the source met the general duty to minimize emissions during a 
failure to meet an applicable standard.
    We will no longer require owners or operators to determine whether 
actions taken to correct a malfunction are consistent with an SSM plan, 
because plans would no longer be required. The proposed amendments, 
therefore, eliminate the cross reference to 40 CFR 63.10(d)(5)(i) that 
contains the description of the previously required SSM report format 
and submittal schedule from this section. These specifications are no 
longer necessary because the events will be reported in otherwise 
required reports with similar format and submittal requirements.
    We are proposing to revise the Table 1 entry for 40 CFR 
63.10(d)(5)(ii) by adding an entry and indicating ``no'' in column 2. 
Section 63.10(d)(5)(ii) describes an immediate report for SSM when a 
source failed to meet an applicable standard but did not follow the SSM 
plan. We will no longer require owners and operators to report when 
actions taken during a SSM were not consistent with an SSM plan, 
because plans would no longer be required.
    We are proposing to revise the Table 1 entry for 40 CFR 
63.10(d)(5)(i) by changing the ``yes'' in column 2 to ``no.'' Section 
63.10(d)(5)(i) describes the reporting requirements for SSM when a 
source failed to meet an applicable standard and was subject to 40 CFR 
63.6(e)(3). To replace the General Provisions requirement, the EPA is 
proposing to revise reporting requirements in 40 CFR 63.1590(f) and 
(g), which referred to SSM plans. The revised language for 40 CFR 
63.1590(f) and (g) is proposed to be in 63.1590(b) and (f) 
respectively. Also, a report has been added at 63.1590(a)(4) for each 
failure to meet an applicable standard at an affected source, the owner 
or operator must report the failure and event to the Administrator in 
an annual Compliance Report. The report must contain the date, time, 
duration, and the cause of each event (including unknown cause, if 
applicable), and a sum of the number of events in the reporting period. 
The report must list for each event the affected source or equipment, 
an estimate of the quantity of each regulated pollutant emitted over 
any emission limit, and a description of the method used to estimate 
the emissions.
    Examples of such methods would include product-loss calculations, 
mass balance calculations, measurements when available, or engineering 
judgment based on known process parameters. The EPA is proposing this 
requirement to ensure that there is adequate information to determine 
compliance, to allow the EPA to determine the severity of the failure 
to meet an applicable standard, and to provide data that may document 
how the source met the general duty to minimize emissions during a 
failure to meet an applicable standard.
    We are proposing to revise Table 1 by adding an entry for 40 CFR 
63.10(d)(5)(ii) and indicating ``no'' in column 2. Section 
63.10(d)(5)(ii) describes an immediate report for SSM when a source 
failed to meet an applicable standard, was subject to 40 CFR 
63.6(e)(3), but did not follow the plan. We will no longer require 
owners or operators to report when actions taken during SSM were not 
consistent with an SSM plan, because plans would no longer be required.
4. Electronic Reporting
    Through this proposal, the EPA is proposing that owners and 
operators of POTW treatment plants submit electronic copies of required 
performance test reports and annual reports through the EPA's Central 
Data Exchange (CDX) using the Compliance and Emissions Data Reporting 
Interface (CEDRI). The EPA believes that the electronic submittal of 
the reports addressed in this proposed rulemaking will increase the 
usefulness of the data contained in those reports, is in keeping with 
current trends in data availability, will further assist in the 
protection of public health and the environment, and will ultimately 
result in less burden on the regulated community. Under current 
requirements, paper reports are often stored in filing cabinets or 
boxes, which make the reports more difficult to obtain and use for data 
analysis and sharing. Electronic storage of such reports would make 
data more accessible for review, analyses, and sharing. Electronic 
reporting can also eliminate paper-based, manual processes, thereby 
saving time and resources, simplifying data entry, eliminating 
redundancies, minimizing data reporting errors, and providing data 
quickly and accurately to the affected facilities, air agencies, the 
EPA, and the public.
    In 2011, in response to Executive Order 13563, the EPA developed a 
plan \28\ to periodically review its regulations to determine if they 
should be modified, streamlined, expanded, or repealed in an effort to 
make regulations more effective and less burdensome. The plan includes 
replacing outdated paper reporting with electronic reporting. In 
keeping with this plan and the White House's Digital Government 
Strategy,\29\ in 2013 the EPA issued an Agency-wide policy specifying 
that new regulations will require reports to be electronic to the 
maximum extent

[[Page 95383]]

possible. By requiring electronic submission of specified reports in 
this proposed rule, the EPA is taking steps to implement this policy.
---------------------------------------------------------------------------

    \28\ EPA's Final Plan for Periodic Retrospective Reviews, August 
2011. Available at: https://www.epa.gov/sites/production/files/2015-09/documents/eparetroreviewplan-aug2011_0.pdf.
    \29\ Digital Government: Building a 21st Century Platform to 
Better Serve the American People, May 2012. Available at: https://www.whitehouse.gov/sites/default/files/omb/egov/digital-government/digital-government-strategy.pdf.
---------------------------------------------------------------------------

    The EPA Web site that stores the submitted electronic data, 
WebFIRE, will be easily accessible to everyone and will provide a user-
friendly interface that any stakeholder could access. By making data 
readily available, electronic reporting increases the amount of data 
that can be used for many purposes. One example is the development of 
emissions factors. An emissions factor is a representative value that 
attempts to relate the quantity of a pollutant released to the 
atmosphere with an activity associated with the release of that 
pollutant (e.g., kilograms of particulate emitted per megagram of coal 
burned). Such factors facilitate the estimation of emissions from 
various sources of air pollution and are an important tool in 
developing emissions inventories, which in turn are the basis for 
numerous efforts, including trends analysis, regional and local scale 
air quality modeling, regulatory impact assessments, and human exposure 
modeling. Emissions factors are also widely used in regulatory 
applicability determinations and in permitting decisions.
    The EPA has received feedback from stakeholders asserting that many 
of the EPA's emissions factors are outdated or not representative of a 
particular industry emission source. While the EPA believes that the 
emissions factors are suitable for their intended purpose, we recognize 
that the quality of emissions factors varies based on the extent and 
quality of underlying data. We also recognize that emissions profiles 
on different pieces of equipment can change over time due to a number 
of factors (fuel changes, equipment improvements, industry work 
practices), and it is important for emissions factors to be updated to 
keep up with these changes. The EPA is currently pursuing emissions 
factor development improvements that include procedures to incorporate 
the source test data that we are proposing be submitted electronically. 
By requiring the electronic submission of the reports identified in 
this proposed action, the EPA would be able to access and use the 
submitted data to update emissions factors more quickly and 
efficiently, creating factors that are characteristic of what is 
currently representative of the relevant industry sector. Likewise, an 
increase in the number of test reports used to develop the emissions 
factors will provide more confidence that the factor is of higher 
quality and representative of the whole industry sector.
    Additionally, by making the records, data, and reports addressed in 
this proposed rulemaking readily available, the EPA, the regulated 
community, and the public will benefit when the EPA conducts its CAA-
required technology and risk-based reviews. As a result of having 
performance test reports and air emission reports readily accessible, 
our ability to carry out comprehensive reviews will be increased and 
achieved within a shorter period of time. These data will provide 
useful information on control efficiencies being achieved and 
maintained in practice within a source category and across source 
categories for regulated sources and pollutants. These reports can also 
be used to inform the technology-review process by providing 
information on improvements to add-on control technology and new 
control technology.
    Under an electronic reporting system, the EPA's Office of Air 
Quality Planning and Standards (OAQPS) would have air emissions and 
performance test data in hand; OAQPS would not have to collect these 
data from the EPA Regional Offices or from delegated air agencies or 
industry sources in cases where these reports are not submitted to the 
EPA Regional Offices. Thus, we anticipate fewer or less substantial 
ICRs in conjunction with prospective CAA-required technology and risk-
based reviews may be needed. We expect this to result in a decrease in 
time spent by industry to respond to data collection requests. We also 
expect the ICRs to contain less extensive stack testing provisions, as 
we will already have stack test data electronically. Reduced testing 
requirements would be a cost savings to industry. The EPA should also 
be able to conduct these required reviews more quickly, as OAQPS will 
not have to include the ICR collection time in the process or spend 
time collecting reports from the EPA Regional Offices. While the 
regulated community may benefit from a reduced burden of ICRs, the 
general public benefits from the Agency's ability to provide these 
required reviews more quickly, resulting in increased public health and 
environmental protection.
    Electronic reporting could minimize submission of unnecessary or 
duplicative reports in cases where facilities report to multiple 
government agencies and the agencies opt to rely on the EPA's 
electronic reporting system to view report submissions. Where air 
agencies continue to require a paper copy of these reports and will 
accept a hard copy of the electronic report, facilities will have the 
option to print paper copies of the electronic reporting forms to 
submit to the air agencies, and, thus, minimize the time spent 
reporting to multiple agencies. Additionally, maintenance and storage 
costs associated with retaining paper records could likewise be 
minimized by replacing those records with electronic records of 
electronically submitted data and reports.
    Air agencies could benefit from more streamlined and automated 
review of the electronically submitted data. For example, because the 
performance test data would be readily-available in a standard 
electronic format, air agencies would be able to review reports and 
data electronically rather than having to conduct a review of the 
reports and data manually. Having reports and associated data in 
electronic format will facilitate review through the use of software 
``search'' options, as well as the downloading and analyzing of data in 
spreadsheet format. Additionally, air agencies would benefit from the 
reported data being accessible to them through the EPA's electronic 
reporting system wherever and whenever they want or need access (as 
long as they have access to the Internet). The ability to access and 
review air emission report information electronically will assist air 
agencies to more quickly and accurately determine compliance with the 
applicable regulations, potentially allowing a faster response to 
violations which could minimize harmful air emissions. This benefits 
both air agencies and the general public.
    The proposed electronic reporting of data is consistent with 
electronic data trends (e.g., electronic banking and income tax 
filing). Electronic reporting of environmental data is already common 
practice in many media offices at the EPA. The changes being proposed 
in this rulemaking are needed to continue the EPA's transition to 
electronic reporting.
5. Reporting
    In addition to the changes made to reporting to address the court 
decision in Sierra Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 2008) on SSM 
requirements described in section IV.D.3 of this preamble, we are 
proposing several other changes to the reporting requirements. We are 
proposing to add an annual report; to remove language that is redundant 
with 40 CFR part 63, subpart A, general provision requirements; and to 
not delegate the approval of the Inspection and Monitoring Plan. We are 
also asking for comment on requiring specific test methods and modeling 
procedures instead of allowing the POTW to specify

[[Page 95384]]

their methods in the Inspection and Monitoring Plan. Our analyses and 
proposed changes related to these issues are presented below.
    Annual Report. EPA is proposing to add a requirement to submit an 
annual report. The proposed contents for the annual report include 
general identification information for the POTW; information on the 
monthly HAP fraction emitted calculation results; and cover inspection 
results for new or reconstructed POTW, depending on which compliance 
method the POTW selects. Also, we are proposing to include a 
requirement to report information about periods when the POTW has a 
failure to meet a standard as part of the annual report. The failure to 
meet report is discussed in more detail in section IV.D.3.g. We are 
also proposing that the annual report be submitted electronically. The 
rationale and benefits of having this report submitted electronically 
is discussed in section IV.D.4 of this preamble.
    EPA is proposing the annual report to address the changes in SSM 
requirements as described in section IV.D.3.g, to receive timely 
compliance information from the POTW, and as a method to collect 
additional information to enhance our ability to carry out 
comprehensive reviews within a shorter period of time. These data will 
provide useful information on HAP fraction emissions and inspection 
results across regulated POTW. These reports can be used to inform the 
technology-review process, reduce the need for complex ICRs, and could 
result in a decrease in time spent by industry in responding to data 
collection requests.
    For existing POTW, it is proposed that the initial annual report 
will cover the first year after the compliance date, which is one year 
after promulgation, and 3 months are proposed to allow time for the 
POTW to compile and prepare the information for submittal. Therefore, 
the first annual report for existing POTW must be submitted to the 
Administrator 27 months after the promulgation of this rulemaking. For 
new POTW, the initial annual report must be submitted 15 months after 
the POTW becomes subject to the rule. The initial annual report must 
cover the 12-month period following the day the new POTW becomes 
subject, with 3 months proposed to allow the POTW time to compile and 
prepare the submittal. All subsequent annual reports, for new or 
existing POTW, must be submitted annually thereafter.
    General Provision requirements. EPA is proposing to revise the 
reporting and notification requirements in 40 CFR 63.1590 and 63.1591 
by removing those requirements that are redundant to requirements that 
are included in the General Provisions (40 CFR 63, subpart A) and 
marked as applicable in Table 1 of the POTW NESHAP. Specifically, much 
of the language in the 2002 POTW NESHAP requirements in 40 CFR 
63.1590(a), (b), (d), and 40 CFR 63.1591(a) and (b) is the same or very 
similar to the requirements in the general provisions at 40 CFR 
63.9(h)(2), (h)(3), (a)(4), (a)(4), and (b)(2), respectively. EPA has 
simplified the language by removing these redundant requirements and 
removed possible confusion caused by two sets of requirements.
    In addition to removing these redundant requirements, EPA is 
proposing to add provisions that provide specific information on what 
is required in the Notification of Compliance Status for POTW, see 
63.1591(b). We have proposed that submitting an Inspection and 
Monitoring Plan required for POTW meeting the HAP fraction emitted 
standard satisfies the requirement for submitting a Notification of 
Compliance Status. We have also clarified in the proposed rule, for new 
or reconstructed POTW that select the cover and control compliance 
option, the Notification of Compliance Status report must include a 
description of the POTW treatment units and installed covers, in 
addition to the performance test results.
    Inspection and Monitoring Plan. The Inspection and Monitoring Plan 
is required in 40 CFR 63.1588(c) for a POTW meeting the HAP fraction 
emitted standard. It requires the POTW to document their plan for 
determining the HAP faction emitted, including the test methods and 
equipment to be used to collect the necessary data, the method for 
calculating the HAP fraction emitted, and the method that will be used 
to demonstrate continuous compliance with the HAP fraction emitted 
standard. The Inspection and Monitoring Plan must be submitted for 
approval. EPA is proposing in this rulemaking that the Inspection and 
Monitoring Plan can only be approved by the EPA and the authority to 
approve this plan cannot be delegated to a state, local or tribal 
agency. Because the methods and procedures used to determine the HAP 
fraction emitted are critical in accurately determining whether the 
POTW is in compliance, and the continuous compliance monitoring methods 
proposed by the POTW in their Inspection and Monitoring Plan could vary 
widely, EPA is retaining this authority to ensure that consistent and 
accurate test and monitoring methods are used. EPA considers it 
necessary to keep this approval authority so that all Inspection and 
Monitoring Plans can be reviewed consistently by one agency.
    Test Methods and Modeling Procedures/Software. In the Inspection 
and Monitoring Plans, the POTW must specify the test methods they will 
use to determine flowrates and HAP concentrations of incoming 
wastewater streams, as well as how they will model and determine their 
HAP emissions. We are considering requiring specific test methods that 
must be used to determine the flowrate of wastewater to the POTW and 
the HAP concentrations in incoming wastewater streams. We are also 
considering requiring specific modeling procedures and/or software to 
be used to determine HAP emissions. By specifying the specific test 
methods and modeling procedures to be used for this data and not 
allowing POTW to select any method they choose, EPA can ensure 
consistency and accuracy of the data used to determine compliance with 
the rule. EPA requests comment on whether we should require specific 
test methods and modeling procedures/software in the final regulation. 
We request comment on which test methods or modeling procedures/
software should be required. We are interested in information on test 
methods and modeling procedures/software with respect to their 
accuracy, what are typically used at POTW, and whether there are 
specific methods that are required in Title V or NPDES permit 
requirements.
6. Other Corrections or Clarifications
    The EPA is also proposing the following technical corrections:
     Revising all references to ``new or reconstructed POTW'' 
to refer to ``new POTW'' because the definition of ``new'' includes 
reconstructed POTW.
     Combining text from 40 CFR 63.1581 and 63.1582 because the 
language was redundant and confusing. Revising 40 CFR 63.1581 to 
include all combined text. Revising 40 CFR 63.1583(c) to include the 
text from the current 40 CFR 63.1582(c).
     Revising 40 CFR 63.1586(b)(1) to require covers ``designed 
and operated to prevent exposure of the wastewater to the atmosphere.'' 
instead of ``designed and operated to minimize exposure of the 
wastewater to the atmosphere.'' This clarification has also been made 
to the definition of ``cover'' in 40 CFR 63.1595.
     Revising 40 CFR 63.1587 to include compliance requirements 
that are currently found in 40 CFR 63.1584 and 63.1587 and deleting 40 
CFR 63.1584.
     Revising all references to ``annual'' rolling average to 
``12-month'' rolling

[[Page 95385]]

average to clarify that the HAP fraction must be determined on a 
monthly basis and not an annual basis.
     Revising all references to ``annual HAP mass loadings'' 
and ``annual HAP emissions'' to now state ``monthly HAP mass loadings'' 
and ``monthly HAP emissions'' to further clarify that the HAP faction 
must be determined on a monthly basis.
     Clarifying method for calculating the HAP fraction 
emitted. Moving the detailed instructions about how the HAP fraction 
emitted should be calculated from 40 CFR 63.1588(c)(4) to 40 CFR 
63.1588(c)(3). The requirements in 40 CFR 63.1588(c)(3) specifically 
address how the HAP fraction emitted should be calculated, while the 
requirements in 40 CFR 63.1588(c)(4) are about monitoring for 
continuous compliance.
     Revising 40 CFR 63.1588(a)(3) to clarify that a cover 
defect must be repaired within 45 ``calendar'' days; currently the 
paragraph says ``45 days.''
     Adding definitions of existing source/POTW and new source/
POTW to 40 CFR 63.1595 to clarify the date that determines whether a 
POTW is existing or new.
     Revising the definition of ``affected source'' in 40 CFR 
63.1595 to clarify that the affected source is the source that is 
subject to the rule.
     Revising references to ``POTW treatment plant'' to refer 
to ``POTW'' to clarify that the rule applies to all parts of the POTW 
and not just the treatment plant portion. Updating the title of 40 CFR 
63.1588 to ``How do Group 1 and Group 2 POTW demonstrate compliance?'' 
from ``What inspections must I conduct?'' The new title better reflects 
the contents of this section.
     Removing the details on how to calculate the HAP fraction 
emitted from the definition of HAP fraction emitted. The procedure for 
how to calculate the HAP fraction emitted is provided within the text 
of the rule. Having a summarized version of this procedure in the 
definition was redundant and could cause confusion where the language 
was not the same.
     Revising two references to dates to insert the actual 
date. The phrase ``six months after October 26, 1999'' was replaced 
with ``April 26, 2000''; and the phrase ``60 days after October 26, 
1999'' was replaced with ``December 27, 1999''. These changes do not 
result in a change in the date, it only clarifies the specific dates 
being referenced.
     Clarifying that the reports required in 40 CFR 
63.1589(b)(1) include the records associated with the HAP loading and 
not just the records associated with the HAP emissions determination.
     Removing definition of ``Reconstruction'' in 40 CFR 
63.1595 as ``Reconstruction'' is already defined in the General 
Provisions of 40 CFR 63.2.

E. What compliance dates are we proposing?

    The EPA is proposing that all of the amendments being proposed in 
this action would be effective on the date 30 days after these proposed 
amendments are final, see 40 CFR 63.1587. Additionally, the EPA is 
proposing a 12-month compliance schedule so that existing non-
industrial (Group 2) POTW treatment plants have time to develop the 
recordkeeping and reporting systems needed to comply with the 
requirements of the HAP fraction emission limit. Likewise, industrial 
(Group 1) POTW treatment plants need time to develop methods to 
demonstrate compliance with both the POTW NESHAP and the other 
applicable NESHAP, including development of the recordkeeping and 
reporting systems, and 12 months will provide industrial (Group 1) POTW 
the time needed to make these changes. Finally, POTW need time to 
examine their SIU pretreatment permits and evaluate if additional 
limits should be incorporated, and issue those revised permits. We 
estimate that 12 months should provide the time necessary to perform 
this evaluation and revise permits, as needed. Table 4 below describes 
the compliance dates and applicable standards for new and existing 
sources based on their subcategory and date of construction or 
reconstruction.

  Table 4 to Subpart VVV of Part 63--Compliance Dates and Requirements
------------------------------------------------------------------------
                                                      And the owner or
    If the construction/        Then the owner or      operators must
reconstruction date is . . .     operators must     achieve compliance .
                                comply with . . .            . .
------------------------------------------------------------------------
Group 1 POTW:
    (1) After December 27,    (i) New source        Upon initial
     2016.                     requirements in       startup.
                               Sec.  Sec.
                               63.1583(b);
                               63.1586(b) or (c);
                               63.1586(d); and
                               63.1588 through
                               63.1591.
    (2) After December 1,     (i) New source        (i) Upon initial
     1998 but on or before     requirements in       startup through the
     December 27, 2016.        Sec.   63.1583(b)     date 12 months
                               but instead of        after the final
                               complying with both   rule is published
                               requirements, you     in the Federal
                               must comply with      Register.
                               the most stringent   (ii) On or before
                               requirement \1\.      date 12 months
                              (ii) New source        after the final
                               requirements in       rule is published
                               Sec.  Sec.            in the Federal
                               63.1586(b) or (c);    Register.
                               63.1586(d); and
                               63.1588 through
                               63.1591.
    (3) On or before          (i) Existing source   (i) By the
     December 1, 1998.         requirements in       compliance date
                               Sec.   63.1583(a)     specified in the
                               but instead of        other applicable
                               complying with both   NESHAP.
                               requirements, you    (ii) On or before
                               must comply with      date 12 months
                               only the other        after the final
                               applicable NESHAP.    rule is published
                              (ii) Existing source   in the Federal
                               requirements in       Register.
                               Sec.  Sec.
                               63.1583(a);
                               63.1586(a) and (d);
                               and 63.1588 through
                               63.1591.
Group 2 POTW:
    (4) After December 27,    (i) New source        Upon initial
     2016.                     requirements in       startup.
                               Sec.  Sec.
                               63.1586(b) or (c);
                               63.1586(d); and
                               63.1588 through
                               63.1591.
    (5) After December 1,     (i) New source        (i) Upon initial
     1998 but on or before     requirements in       startup through the
     December 27, 2016.        Sec.   63.1586(b)     date 12 months
                               or (c) \1\.           after the final
                              (ii) New source        rule is published
                               requirements in       in the Federal
                               Sec.  Sec.            Register.
                               63.1586(b) or (c);   (ii) On or before
                               63.1586(d); and       date 12 months
                               63.1588 through       after the final
                               63.1591.              rule is published
                                                     in the Federal
                                                     Register.
    (6) On or before          (i) Existing source   On or before date 12
     December 1, 1998.         requirements in       months after the
                               Sec.  Sec.            final rule is
                               63.1586(a) and (d);   published in the
                               and 63.1588 through   Federal Register.
                               63.1591.
------------------------------------------------------------------------
\1\ Note: This represents the requirements in the original 1999 NESHAP,
  which are applicable until 12-months after the final rule is published
  in the Federal Register. During those 12-months, you must transition
  to the new requirements in Table 2 (2)(ii) and (5)(ii) for Group 1 and
  Group 2 POTW, respectively.

[[Page 95386]]

    The tasks necessary for existing and new POTW to comply with 
electronic reporting of annual reports requires two years for 
compliance. The EPA is proposing that the compliance date for 
electronically submitting annual reports would be two years after the 
date the final rule is published in the Federal Register or once the 
form has been available in CEDRI for at least 1 year, whichever date is 
later. Prior to that date, you must submit these reports to the 
Administrator at the address listed in 40 CFR 63.13, unless another 
format is agreed upon with the Administrator. We will post the date 
that each form becomes available on the CEDRI Web site (https://www.epa.gov/electronic-reporting-air-emissions/compliance-and-emissions-data-reporting-interface-cedri) and notice will be sent out 
through the Clearinghouse for Inventories and Emissions Factors (CHIEF) 
Listserv (https://www.epa.gov/chief/chief-listserv). This extended 
compliance period affords you more time to reprogram systems that 
collect data for periodic reports and to become familiar with the new 
reporting form. This time extension will also allow air agencies more 
time to implement electronic reporting and to begin making any needed 
permit revisions to accommodate electronic reporting. In addition, it 
will provide sufficient time for you and us to conduct beta testing of 
the CEDRI form in advance of initial reporting. We believe that this 
will instill confidence that any technical issues with the forms will 
be resolved prior to requiring the use of the forms for compliance 
purposes, such that use of the forms will not interfere with your 
ability to comply with the requirement for electronic submittal.
    The tasks necessary to comply with the other proposed amendments 
require no time or resources. Therefore, the EPA believes that existing 
facilities will be able to comply with the other proposed amendments, 
including those related to SSM periods, as soon as the final rule is 
effective, which will be the date 30 days after publication of the 
final rule. Therefore, the EPA is specifically soliciting comment and 
additional data on the burden of complying with the other proposed 
amendments.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    The EPA estimates, based on the responses to the 2015 ICR and the 
2011 NEI, that there are six POTW that are engaged in treatment of 
industrial wastewater and are currently subject to the POTW NESHAP. Two 
of these facilities are considered industrial (Group 1) POTW, while the 
remaining four are considered non-industrial (Group 2) POTW. The EPA 
estimates that all six POTW currently subject to the POTW NESHAP would 
be affected by the proposed pretreatment requirements, and the two 
industrial (Group 1) POTW would be affected by the requirement for 
these facilities to comply with both the requirements for existing non-
industrial (Group 2) POTW (see section IV.C.3 of this preamble) and the 
other applicable NESHAP. In addition, the EPA estimates that the four 
existing non-industrial (Group 2) POTW would be affected by the 
proposed requirement to meet the 0.08 HAP fraction emitted limit. The 
EPA is not currently aware of any planned or potential new or 
reconstructed industrial (Group 1) or non-industrial (Group 2) POTW.

B. What are the air quality impacts?

    The EPA estimates that annual organic HAP emissions from the six 
POTW subject to the rule are approximately 20 tpy; there are no 
expected inorganic HAP emissions from this category. The EPA does not 
anticipate any additional emission reductions from the proposed changes 
to the rule because each of the subject facilities is currently able to 
meet the proposed emission limits and there are no anticipated new or 
reconstructed facilities.

C. What are the cost impacts?

    The six POTW subject to this proposal will incur costs to meet 
recordkeeping and reporting requirements. Nationwide annual costs 
associated with the proposed requirements are estimated to be $10,530 
per year. We believe that the six POTW which are known to be subject to 
this proposed rule can meet these proposed requirements without 
incurring additional capital or operational costs. Therefore, the only 
costs associated with this proposed rule are related to recordkeeping 
and reporting. For further information on the proposed requirements for 
this rule, see section IV of this preamble. For further information on 
the costs associated with the proposed requirements of this rule, see 
the document titled Supporting Statement for Publicly Owned Treatment 
Works in the docket. The Technology Review Memo in the docket for this 
action presents cost estimates associated with the regulatory options 
that were not selected for inclusion in this proposed rule.

D. What are the economic impacts?

    The economic impact analysis is designed to inform decision makers 
about the potential economic consequences of a regulatory action. For 
the current proposal, the EPA estimated the annual cost of 
recordkeeping and reporting as a percentage of reported sewage fees 
received by the affected POTW. For the proposed regulations, costs are 
expected to be less than 0.05 percent of collected sewage fees, based 
on publicly available financial reports from the fiscal year ending in 
2015 for the affected entities.
    In addition, the EPA performed a screening analysis for impacts on 
small businesses by comparing estimated population served by the 
affected entities to the population limit set forth by the U.S. Small 
Business Administration. The screening analysis found that the 
population served for all affected entities is greater than the limit 
qualifying a public entity as small.
    More information and details of EPA's analysis of the economic 
impacts, including the conclusions stated above, is provided in the 
technical document ``Economic Impact Analysis for the Publicly Owned 
Treatment Works National Emissions Standards for Hazardous Air 
Pollutants Risk and Technology Review,'' which is available in the 
docket for this proposed rule (Docket ID No. EPA-HQ-OAR-2016-0490).

E. What are the benefits?

    As all affected entities are already in compliance with the 
proposed regulations, no additional emissions reductions are expected, 
but the proposed requirements will ensure that future emissions do not 
increase beyond current levels. Moreover, the EPA believes that the 
electronic submittal of the reports addressed in this proposed 
rulemaking will increase the usefulness of the data contained in those 
reports, is in keeping with current trends of data availability, will 
further assist in the protection of public health and the environment, 
and will ultimately result in less burden on the regulated community. 
See section IV.D.4 of this preamble for more information.

VI. 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

[[Page 95387]]

for risk modeling. Such data should include supporting documentation in 
sufficient detail to allow characterization of the quality and 
representativeness of the data or information. Section VII of this 
preamble provides more information on submitting data.
    In addition to the requests for comment in this section, the EPA 
requests comments on topics already identified in these sections:
    The EPA requests identification of any additional POTW that are 
subject to the POTW NESHAP, other than those listed in the list of 
facilities in the POTW RTR database. The database can be found in the 
docket for this action. In addition, the EPA is not currently aware of 
any planned or potential new or reconstructed industrial (Group 1) or 
non-industrial (Group 2) POTW. Thus, the EPA requests comment on any 
other POTW that are subject to the POTW NESHAP or could potentially 
become subject in the future.
    The EPA requests comment on the extent to which HAP emissions from 
other POTW not evaluated in the environmental risk screening assessment 
may cause adverse environmental effects. Such information should 
include references to peer-reviewed ecological effects benchmarks that 
are of sufficient quality for making regulatory decisions, as well as 
information on the presence of organisms located near facilities within 
the source category that such benchmarks indicate could be adversely 
affected.
    We are requesting comment on whether POTW should evaluate volatile 
organic HAP and set limits within the pretreatment programs for these 
pollutants.
    We are soliciting comment on the effectiveness of caustic scrubbers 
and carbon adsorbers to co-control HAP while primarily functioning as 
odor control devices. In addition, we are requesting quantitative 
feedback on the effectiveness of using covers only to suppress 
emissions, and identification of any other key operating parameters 
that may affect HAP emissions levels such as ventilation rates or 
control device maintenance practices.
    We are also requesting comment on whether we should provide an 
alternative to the 0.08 HAP fraction emitted standard that would 
require either covering the primary clarifier, or would require 
covering and control of all primary treatment units (except primary 
clarifiers, which would only require covering). The second alternative 
would keep the requirements for existing sources consistent with those 
for new sources, namely to cover and control their primary treatment 
units or to meet the HAP fraction standard.
    We do not intend to include small POTW that are not a major source 
of HAP emissions. Therefore, we request comment on whether the proposed 
revisions to the applicability criteria inadvertently include POTW that 
would otherwise have not been included in a major source rule.
    We are requesting comment on any specific test methods or emission 
estimation software that EPA could require for determining the HAP 
fraction emitted. Additionally, we are requesting comment on whether 
EPA should specify test methods and emission estimation software 
instead of allowing the POTW to submit site-specific methods with the 
Inspection and Monitoring Plan.
    We are requesting comment on our proposal that subject POTW would 
be in compliance with all of the amendments by 1 year after publication 
of the final rule. We believe that is enough time for (1) non-
industrial (Group 2) POTW treatment plants need to set up recordkeeping 
and reporting systems to comply with the HAP fraction emission limit; 
(2) industrial (Group 1) POTW treatment plants to develop recordkeeping 
and reporting systems to comply with both the POTW NESHAP and the other 
applicable NESHAP; and (3) POTW to examine their SIU pretreatment 
permits and evaluate if additional limits should be incorporated and 
issue those revised permits. The EPA also believes that existing 
facilities will be able to comply with the other proposed amendments, 
including those related to SSM periods, as soon as the final rule is 
effective, which will be the date 30 days after publication of the 
final rule. The EPA is specifically soliciting comment and additional 
data on the burden of complying with the other proposed amendments.

VII. Submitting Data Corrections

    The site-specific emissions profiles used in the source category 
risk and demographic analyses and instructions are available for 
download on the RTR Web site 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 Web site, 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 No. EPA-HQ-OAR-2016-0490 (through the method 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 
site at http://www.epa.gov/ttn/atw/rrisk/rtrpg.html.

VIII. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.

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 and, therefore, 
was not submitted to OMB for review.

B. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have 
been submitted for approval to OMB under the PRA. The ICR document that 
the EPA prepared has been assigned EPA ICR number 1891.08. You can find 
a copy of the ICR in the docket for this rule, and it is briefly 
summarized here.
    The information to be collected includes annual reports of the HAP 
fraction emitted, an inspection and monitoring plan explaining how 
compliance with the HAP fraction emitted limit will be achieved, and 
pretreatment reports required under 40

[[Page 95388]]

CFR part 403. This information will be used to ensure that the 
requirements are being implemented and are complied with on a 
continuous basis. Specifically, the information will be used to: (1) 
Identify sources subject to the standards; (2) ensure that the POTW 
NESHAP is being properly applied; and (3) ensure that the POTW NESHAP 
is being complied with.
    Respondents/affected entities: The respondents to the recordkeeping 
and reporting requirements are owners and operators of POTW. The North 
American Industry Classification System code for the respondents 
affected by the standard is 221320 (Sewage Treatment Facilities), which 
corresponds to the United States Standard Industrial Classification 
code 4952 (Sewerage Systems).
    Respondent's obligation to respond: Respondents are obligated to 
respond in accordance with the reporting requirements under 40 CFR 
63.1590(a)(2), 63.1590(e), and 63.1590(g).
    Estimated number of respondents: Six.
    Frequency of response: Twelve per year.
    Total estimated burden: Ninety-nine hours (per year). Burden is 
defined at 5 CFR 1320.3(b).
    Total estimated cost: $10,350 (per year), includes $0 annualized 
capital or operation and maintenance costs.
    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.
    Submit your comments on the Agency's need for this information, the 
accuracy of the provided burden estimates, and any suggested methods 
for minimizing respondent burden to the EPA using the docket identified 
at the beginning of this rule. You may also send your ICR-related 
comments to OMB's Office of Information and Regulatory Affairs via 
email to oria_submissions@omb.eop.gov, Attention: Desk Officer for the 
EPA. Since OMB is required to make a decision concerning the ICR 
between 30 and 60 days after receipt, OMB must receive comments no 
later than January 26, 2017. The EPA will respond to any ICR-related 
comments in the final rule.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities. There are no 
small entities affected in this regulated industry. See the technical 
document, Economic Impact Analysis for the Publicly Owned Treatment 
Works National Emissions Standards for Hazardous Air Pollutants Risk 
and Technology Review which is available in the docket for this 
proposed rule (Docket ID No. EPA-HQ-OAR-2016-0490) for more detail.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more as described in UMRA, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments. The action imposes 
no enforceable duty on any state, local, or tribal governments or the 
private sector.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

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

    This action does not have tribal implications as specified in 
Executive Order 13175. As discussed in section II.B.1 of this preamble, 
we have identified only seven POTW that are subject to this proposed 
rule and none of those POTW are owned or operated by tribal 
governments. Thus, Executive Order 13175 does not apply to this action.

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

    The action is not subject to Executive Order 13045 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's health and risk assessments are contained in 
sections III.A and B and sections IV.A and B of this preamble and the 
Residual Risk Report memorandum contained in the docket for this 
rulemaking.

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

    This action is not subject to Executive Order 13211 because it is 
not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act (NTTAA)

    This rulemaking does not involve technical standards.

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

    The EPA believes that this action does not have disproportionately 
high and adverse human health or environmental effects on minority 
populations, low-income populations, and/or indigenous peoples, as 
specified in Executive Order 12898 (59 FR 7629, February 16, 1994).
    The documentation for this decision is contained in section III.A.6 
of this preamble and in the corresponding technical report, Risk and 
Technology Review--Analysis of Socio-Economic Factors for Populations 
Living Near Publicly Owned Treatment Works, available in the docket for 
this action. The proximity results indicate, for eight of the 11 
demographic categories, that the population percentages within 5 km and 
50 km of source category emissions are greater than the corresponding 
national percentage for those same demographics. However, the results 
of the risk analysis presented in section III.A.6 of this preamble and 
in the corresponding technical report indicate that there are no people 
exposed to a cancer risk greater than or equal to 1-in-1 million as a 
result of emissions from POTW.

List of Subjects in 40 CFR Part 63

    Environmental protection, Air pollution control, Hazardous 
substances, Reporting and recordkeeping requirements.

    Dated: December 8, 2016.
Gina McCarthy,
Administrator.

    For the reasons stated in the preamble, the Environmental 
Protection Agency proposes to amend part 63 of title 40, chapter I, of 
the Code of Federal Regulations 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.

0
2. Subpart VVV of part 63 is revised to read as follows:

[[Page 95389]]

Subpart VVV--National Emission Standards for Hazardous Air Pollutants: 
Publicly Owned Treatment Works
Sec.

Applicability

63.1580 Am I subject to this subpart?
63.1581 Does the subpart distinguish between different types of 
POTW?

Group 1 POTW Description and Requirements

63.1582 [Reserved]
63.1583 What are the emission points and control requirements for a 
Group 1 POTW?
63.1584 [Reserved]
63.1585 How does a Group 1 POTW demonstrate compliance?

Group 1 and Group 2 POTW Requirements

63.1586 What are the emission points and control requirements for 
Group 1 and Group 2 POTW?
63.1587 When do I have to comply?
63.1588 How do Group 1 and Group 2 POTW demonstrate compliance?
63.1589 What records must I keep?
63.1590 What reports must I submit?

General Requirements

63.1591 What are my notification requirements?
63.1592 Which General Provisions apply to my POTW?
63.1593 [Reserved]
63.1594 Who enforces this subpart?
63.1595 List of definitions.

Table 1 to Subpart VVV of Part 63--Applicability of 40 CFR Part 63 
General Provisions to Subpart VVV

Table 2 to Subpart VVV of Part 63--Compliance Dates and Requirements

Subpart VVV--National Emission Standards for Hazardous Air 
Pollutants: Publicly Owned Treatment Works

Applicability

Sec.  63.1580  Am I subject to this subpart?

    (a) You are subject to this subpart if your publicly owned 
treatment works (POTW) has a design capacity to treat at least 5 
million gallons of wastewater per day and treats wastewater from an 
industrial or commercial facility; and either paragraph (a)(1) or (2) 
of this section is true:
    (1) You own or operate a POTW that is a major source of HAP 
emissions; or
    (2) You own or operate a Group 1 POTW regardless of whether or not 
it is a major source of hazardous air pollutants (HAP).
    (b) If your existing POTW is not located at a major source as of 
October 26, 1999, but thereafter becomes a major source for any reason 
other than reconstruction, then, for the purpose of this subpart, your 
POTW would be considered an existing source.

    Note to Paragraph (b): See Sec.  63.2 of the National Emission 
Standards for Hazardous Air Pollutants (NESHAP) General Provisions 
in subpart A of this part for the definitions of major source and 
area source.

    (c) If you commence construction or reconstruction of your POTW 
after December 1, 1998, then the requirements for a new POTW apply.

Sec.  63.1581  Does the subpart distinguish between different types of 
POTW?

    Yes, POTW are divided into two subcategories: Group 1 POTW and 
Group 2 POTW, as described in paragraphs (a) through (c) of this 
section.
    (a) Your POTW is a Group 1 POTW if an industrial discharger 
complies with its NESHAP by using the treatment and control located at 
your POTW. Your POTW accepts the regulated waste stream and provides 
treatment and controls as an agent for the industrial discharger. Group 
1 POTW is defined in Sec.  63.1595.
    (b) Your POTW is a Group 2 POTW if you treat wastewater that is not 
subject to control by another NESHAP or the industrial facility does 
not comply with its NESHAP by using the treatment and controls located 
at your POTW. Group 2 POTW is defined in Sec.  63.1595.
    (c) If, in the future, an industrial discharger complies with its 
NESHAP by using the treatment and control located at your POTW, then 
your Group 2 POTW becomes a Group 1 POTW on the date your POTW begins 
treating that regulated industrial wastewater stream.

Group 1 POTW Description and Requirements

Sec.  63.1582   [Reserved]

Sec.  63.1583  What are the emission points and control requirements 
for a Group 1 POTW?

    (a) The emission points and control requirements for an existing 
Group 1 POTW are both those specified by the appropriate NESHAP for 
which the POTW treats regulated industrial wastewater and those 
emission points and control requirements set forth in Sec.  63.1586(a) 
and (d).
    (b) The emission points and control requirements for a new Group 1 
POTW are both those specified by the appropriate NESHAP for which the 
POTW treats regulated industrial wastewater and those emission points 
and control requirements set forth in Sec.  63.1586(b) or (c), and (d), 
as applicable.
    (c) If your Group 1 POTW accepts one or more specific regulated 
industrial waste streams as part of compliance with one or more other 
NESHAP, then you are subject to all the requirements of each 
appropriate NESHAP for each waste stream and the applicable 
requirements set forth in Sec.  63.1586.
    (d) 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 or 
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.

Sec.  63.1584   [Reserved]

Sec.  63.1585  How does a Group 1 POTW demonstrate compliance?

    (a) A Group 1 POTW demonstrates compliance by operating treatment 
and control devices that meet all requirements specified in the 
appropriate NESHAP.
    (b) A Group 1 POTW must also demonstrate compliance by meeting the 
requirements specified in Sec.  63.1586, as applicable, as well as the 
applicable requirements in Sec. Sec.  63.1587 through 63.1595.

Group 1 and Group 2 POTW Requirements

Sec.  63.1586  What are the emission points and control requirements 
for Group 1 and Group 2 POTW?

    (a) Existing Group 1 and Group 2 POTW must demonstrate that the HAP 
fraction emitted from all emission points up to, but not including, the 
secondary influent pumping station or the secondary treatment units 
does not exceed 0.08 on a 12-month rolling average. You must 
demonstrate that for your POTW, the sum of all HAP emissions from these 
emission points divided by the sum of all HAP mass loadings to the POTW 
results in a 12-month rolling average of the fraction emitted no 
greater than 0.08. You may use any combination of pretreatment, 
wastewater treatment plant modifications, and control devices to 
achieve this performance standard.

[[Page 95390]]

    (b) Except as provided in paragraph (c) of this section, new Group 
1 and Group 2 POTW must install covers on the emission points up to, 
but not including, the secondary influent pumping station or the 
secondary treatment units. These emission points are treatment units 
that include, but are not limited to, influent waste stream conveyance 
channels, bar screens, grit chambers, grinders, pump stations, aerated 
feeder channels, primary clarifiers, primary effluent channels, and 
primary screening stations. In addition, all covered units, except 
primary clarifiers, must have the air in the headspace underneath the 
cover ducted to a control device in accordance with the standards for 
closed-vent systems and control devices in Sec.  63.693, except you may 
substitute visual inspections for leak detection rather than Method 21 
of appendix A-7 of part 60 of this chapter. Covers must meet the 
following requirements:
    (1) Covers must be tightly fitted and designed and operated to 
prevent exposure of the wastewater to the atmosphere. This includes, 
but is not limited to, the absence of visible cracks, holes, or gaps in 
the roof sections or between the roof and the supporting wall; broken, 
cracked, or otherwise damaged seals or gaskets on closure devices; and 
broken or missing hatches, access covers, caps, or other closure 
devices.
    (2) If wastewater is in a treatment unit, each opening in the cover 
must be maintained in a closed, sealed position, unless plant personnel 
are present and conducting wastewater or sludge sampling, or equipment 
inspection, maintenance, or repair.
    (c) As an alternative to the requirements in paragraph (b) of this 
section, a new Group 1 and Group 2 POTW may comply by demonstrating, 
for all emission points up to the secondary influent pumping station or 
the secondary treatment units, that the HAP fraction emitted does not 
exceed 0.014 on a 12-month rolling average. You must demonstrate that 
for your POTW, the sum of all HAP emissions from these units divided by 
the sum of all HAP mass loadings to the POTW results in a 12-month 
rolling average of the HAP fraction emitted of no greater than 0.014. 
You may use any combination of pretreatment, wastewater treatment plant 
modifications, and control devices to achieve this performance 
standard.
    (d) Existing and new Group 1 and Group 2 POTW must develop and 
implement a pretreatment program as defined by Sec.  403.8 of this 
chapter.
    (e) 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 or 
operator to make any further efforts to reduce emissions if the 
requirements of the applicable standard have been met. 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.

Sec.  63.1587  When do I have to comply?

    Sources subject to this subpart are required to achieve compliance 
on or before the dates specified in table 2 to this subpart.

Sec.  63.1588  How do Group 1 and Group 2 POTW demonstrate compliance?

    (a) If you are complying with Sec.  63.1586(b) by using covers, you 
must conduct the following inspections:
    (1) You must visually check the cover and its closure devices for 
defects that could result in air emissions. Defects include, but are 
not limited to, visible cracks, holes, or gaps in the roof sections or 
between the roof and the supporting wall; broken, cracked, or otherwise 
damaged seals or gaskets on closure devices; and broken or missing 
hatches, access covers, caps, or other closure devices.
    (2) You must perform an initial visual inspection within 60 
calendar days of becoming subject to this NESHAP and perform follow-up 
inspections at least once per year, thereafter.
    (3) In the event that you find a defect on a treatment unit in use, 
you must repair the defect within 45 calendar days. If you cannot 
repair within 45 calendar days, you must notify the EPA or the 
designated state authority immediately and report the reason for the 
delay and the date you expect to complete the repair. If you find a 
defect on a treatment unit that is not in service, you must repair the 
defect prior to putting the treatment unit back in wastewater service.
    (b) If you own or operate a control device used to meet the 
requirements for Sec.  63.1586(b), you must comply with the inspection 
and monitoring requirements of Sec.  63.695(c).
    (c) To comply with the performance standard specified in Sec.  
63.1586(a) or (c), you must develop, to the satisfaction of the 
Administrator, an Inspection and Monitoring Plan. This Inspection and 
Monitoring Plan must include, at a minimum, the following:
    (1) A method to determine the influent HAP mass loading, i.e., the 
monthly mass quantity for each HAP entering the wastewater treatment 
plant.
    (2) A method to determine your POTW's monthly HAP emissions for all 
units up to but not including the secondary influent pumping station or 
the secondary treatment units. The method you use to determine your HAP 
emissions, such as modeling or direct source measurement, must:
    (i) Be approved by the Administrator for use at your POTW;
    (ii) Account for all factors affecting emissions from your plant 
including, but not limited to, emissions from wastewater treatment 
units; emissions resulting from inspection, maintenance, and repair 
activities; fluctuations (e.g., daily, monthly, annual, seasonal) in 
your influent wastewater HAP concentrations; annual industrial loading; 
performance of control devices; or any other factors that could affect 
your annual HAP emissions; and
    (iii) Include documentation that the values and sources of all 
data, operating conditions, assumptions, etc., used in your method 
result in an accurate estimation of monthly emissions from your plant.
    (3) A method to demonstrate that your POTW meets the HAP fraction 
emitted standards specified in Sec.  63.1586(a) or (c), i.e., the sum 
of all monthly HAP emissions over a 12-month period from paragraph 
(c)(2) of this section divided by the sum of all monthly HAP mass 
loadings over a 12-month period from paragraph (c)(1) of this section 
results in a fraction emitted of 0.08 or less to demonstrate compliance 
with Sec.  63.1586(a) or 0.014 or less to demonstrate compliance with 
Sec.  63.1586(c). The Inspection and Monitoring plan must require, at a 
minimum, that you perform the calculations shown in paragraphs 
(c)(3)(i) through (viii) of this section by the end of each month for 
the previous month. This calculation shall demonstrate that your 12-
month rolling average of the HAP fraction emitted is 0.08 or less when 
demonstrating compliance with Sec.  63.1586(a) or 0.014 or less when 
demonstrating compliance with Sec.  63.1586(c).
    (i) Determine the average daily flow in million gallons per day 
(MGD) of the wastewater entering your POTW for the previous month;

[[Page 95391]]

    (ii) Determine the concentration of each HAP in your influent 
listed in Table 1 to subpart DD of this part for the previous month;
    (iii) Using the previous month's information in paragraphs 
(c)(3)(i) and (ii) of this section, determine a total monthly flow-
weighted loading in pounds per day (lbs/day) of each HAP entering your 
POTW for the previous month;
    (iv) Sum up the values for each individual HAP loading in paragraph 
(c)(3)(iii) of this section and determine a total monthly flow-weighted 
loading value (lbs/day) for all HAP entering your POTW for the previous 
month;
    (v) Based on the previous month's information in paragraph 
(c)(3)(iii) of this section along with source testing and emission 
modeling, for each HAP, determine the monthly emissions (lbs/day) from 
all wastewater treatment units up to, but not including, secondary 
treatment units for the previous month;
    (vi) Sum the values of emissions for each individual HAP determined 
in paragraph (c)(3)(v) of this section and calculate the total monthly 
emissions value for the previous month for all HAP from all wastewater 
treatment units up to, but not including, secondary treatment units;
    (vii) Calculate the HAP fraction emitted value for the previous 
month, using Equation 1 of this section as follows:

[GRAPHIC] [TIFF OMITTED] TP27DE16.000

Where:

fe monthly = HAP fraction emitted for the previous month
[Sigma]E = Total HAP emissions value from paragraph (c)(3)(vi) of this 
section
[Sigma]L = Total monthly loading from paragraph (c)(3)(iv) of this 
section

    (viii) Average the HAP fraction emitted value for the month 
determined in paragraph (c)(3)(vii) of this section, with the values 
determined for the previous 11 months, to calculate a 12-month rolling 
average of the HAP fraction emitted.
    (4) A method to demonstrate, to the satisfaction of the 
Administrator, that your POTW is in continuous compliance with the 
requirements of Sec.  63.1586(a) or (c). Continuous compliance means 
that your emissions, when averaged over the course of a 12-month 
period, do not exceed the level of emissions that allows your POTW to 
comply with Sec.  63.1586(a) or (c) on a monthly basis. For example, 
you may identify a parameter(s) that you can monitor that assures your 
emissions, when averaged over a 12-month period, will meet the 
requirements in Sec.  63.1586(a) or (c) each month. Some example 
parameters that may be considered for monitoring include your 
wastewater influent HAP concentration and flow, industrial loading from 
your permitted industrial dischargers, and your control device 
performance criteria. Where emission reductions are due to proper 
operation of equipment, work practices, or other operational 
procedures, your demonstration must specify the frequency of 
inspections and the number of days to completion of repairs.
    (d) Prior to receiving approval on the Inspection and Monitoring 
Plan, you must follow the plan submitted to the Administrator as 
specified in Sec.  63.1590(e) or (f), as applicable.

Sec.  63.1589  What records must I keep?

    (a) To comply with the equipment standard specified in Sec.  
63.1586(b), you must prepare and maintain the records required in 
paragraphs (a)(1) through (4) of this section:
    (1) A record for each treatment unit inspection required by Sec.  
63.1588(a). You must include a treatment unit identification number (or 
other unique identification description as selected by you) and the 
date of inspection.
    (2) For each defect detected during inspections required by Sec.  
63.1588(a), you must record the location of the defect, a description 
of the defect, the date of detection, the corrective action taken to 
repair the defect, and the date the repair to correct the defect is 
completed.
    (3) If repair of the defect is delayed as described in Sec.  
63.1588(a)(3), you must also record the reason for the delay and the 
date you expect to complete the repair.
    (4) If you own or operate a control device used to meet the 
requirements for Sec.  63.1586(b), you must comply with the 
recordkeeping requirements of Sec.  63.696(a), (b), (g), and (h).
    (b) To comply with the performance standard specified in Sec.  
63.1586(a) or (c), you must prepare and maintain the records required 
in paragraphs (b)(1) through (3) of this section:
    (1) A record of the methods and data used to determine your POTW's 
monthly HAP loading and emissions as determined in Sec.  63.1588(c)(1) 
and (2);
    (2) A record of the methods and data used to determine that your 
POTW meets the HAP fraction emitted standard (either 0.08 or 0.014), as 
determined in Sec.  63.1588(c)(3); and
    (3) A record of the methods and data that demonstrates that your 
POTW is in continuous compliance with the requirements of Sec.  
63.1588(c)(4).
    (c) To comply with the requirement to meet the pretreatment program 
requirements defined by Sec.  403.8 of this chapter as specified in 
Sec.  63.1586(d), you must maintain records as required in part 403 of 
this chapter.
    (d) An owner or operator must record the malfunction information 
specified in paragraphs (d)(1) through (3) of this section.
    (1) In the event that an affected unit fails to meet an applicable 
standard, record the number of failures. For each failure, record the 
date, time, and duration of the failure.
    (2) For each failure to meet an applicable standard, record and 
retain a list of the affected sources or equipment, an estimate of the 
volume of each regulated pollutant emitted over any emission limit and 
a description of the method used to estimate the emissions.
    (3) Record actions taken to minimize emissions in accordance with 
Sec.  63.1583(d) or Sec.  63.1586(e) and any corrective actions taken 
to return the affected unit to its normal or usual manner of operation.

Sec.  63.1590  What reports must I submit?

    (a) You must submit annual reports containing the information 
specified in paragraphs (a)(1) through (4) of this section, if 
applicable. You must submit annual reports following the procedure 
specified in paragraph (a)(5) of this section. For existing units, the 
initial annual report is due no later than date 27 months after the 
final rule is published in the Federal Register and must cover the 12-
month timeframe beginning date 12 months after the final rule is 
published in the Federal Register. For new units, the initial annual 
report is due 15 months after your POTW becomes subject to the 
requirements in this subpart and must cover the first 12 months of 
operation after your POTW becomes subject to the requirements of this 
subpart. Subsequent annual reports are due by the same date each year 
as the initial annual report and must contain information for the 12-
month period following the 12-month period included in the previous 
annual report.
    (1) The general information specified in paragraphs (a)(1)(i) and 
(ii) of this section must be included in all reports.
    (i) The company name, POTW treatment plant name, and POTW treatment 
plant address; and
    (ii) Beginning and ending dates of the reporting period.
    (2) The monthly HAP fraction emitted as calculated in Sec.  
63.1588(c)(3)(vii) for each month in the 12-month period covered by the 
annual report.

[[Page 95392]]

    (3) If you use covers to comply with the requirements of Sec.  
63.1586(b), you must submit the following:
    (i) The dates of each visual inspection conducted;
    (ii) The defects found during each visual inspection; and
    (iii) For each defect found during a visual inspection, how the 
defects were repaired, whether the repair has been completed and either 
the date each repair was completed or the date each repair is expected 
to be completed.
    (4) If a source fails to meet an applicable standard, report such 
events in the annual 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 pollutants emitted over any emission limit, and a 
description of the method used to estimate the emissions.
    (5) You must submit the report to the Administrator at the 
appropriate address listed in Sec.  63.13, unless the Administrator 
agrees to or specifies an alternate reporting method. Beginning on the 
date 2 years after date the final rule is published in the Federal 
Register or once the reporting form has been available in CEDRI for 1 
year, whichever is later, you must submit subsequent annual reports to 
the EPA via the Compliance and Emissions Data Reporting Interface 
(CEDRI). (CEDRI can be accessed through the EPA's Central Data Exchange 
(CDX) (https://cdx.epa.gov/)). You must use the appropriate electronic 
report in CEDRI for this subpart or an alternate electronic file format 
consistent with the extensible markup language (XML) schema listed on 
the CEDRI Web site (https://www.epa.gov/electronic-reporting-air-emissions/compliance-and-emissions-data-reporting-interface-cedri). The 
date forms become available in CEDRI will be listed on the CEDRI Web 
site. The reports must be submitted by the deadline specified in this 
subpart, regardless of the method in which the reports are submitted.
    (b) If you own or operate a control device used to meet the 
requirements of Sec.  63.1586(b), you must submit the notifications and 
reports required by Sec.  63.697(b), including a notification of 
performance tests; a performance test report; a malfunction report; and 
a summary report. These notifications and reports must be submitted to 
the Administrator, except for performance test reports. Within 60 
calendar days after the date of completing each performance test (as 
defined in Sec.  63.2) required by subpart DD of this part, you must 
submit the results of the performance test following the procedure 
specified in either paragraph (b)(1) or (2) of this section.
    (1) For data collected using test methods supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the EPA's ERT Web site 
(https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test, you must submit the 
results of the performance test to the EPA via CEDRI. Performance test 
data must be submitted in a file format generated through the use of 
the EPA's ERT or an alternate electronic file format consistent with 
the XML schema listed on the EPA's ERT Web site.
    (2) For data collected using test methods that are not supported by 
the EPA's ERT as listed on the EPA's ERT Web site at the time of the 
test, you must submit the results of the performance test to the 
Administrator at the appropriate address listed in Sec.  63.13 subpart 
A of this part, unless the Administrator agrees to or specifies an 
alternate reporting method.
    (3) If you claim that some of the performance test information 
being submitted under paragraph (b)(1) of this section is confidential 
business information (CBI), you must submit a complete file generated 
through the use of the EPA's ERT or an alternate electronic file 
consistent with the XML schema listed on the EPA's ERT Web site, 
including information claimed to be CBI, on a compact disc, flash drive 
or other commonly used electronic storage medium to the EPA. The 
electronic medium must be clearly marked as CBI and mailed to U.S. EPA/
OAQPS/CORE CBI Office, Attention: Group Leader, Measurement Policy 
Group, MD C404-02, 4930 Old Page Rd., Durham, NC 27703. The same ERT or 
alternate file with the CBI omitted must be submitted to the EPA via 
the EPA's CDX as described in paragraph (b)(1) of this section.
    (c) You must comply with the delay of repair reporting required in 
Sec.  63.1588(a)(3).
    (d) You may apply to the Administrator for a waiver of 
recordkeeping and reporting requirements by complying with the 
requirements of Sec.  63.10(f). Electronic reporting to the EPA cannot 
be waived.
    (e) To comply with the performance standard specified in Sec.  
63.1586(a), you must submit, for approval by the Administrator, an 
Inspection and Monitoring Plan explaining your compliance approach by 
date 180 days after the final rule is published in the Federal 
Register.
    (f) To comply with the performance standard specified in Sec.  
63.1586(c), you must submit, for approval by the Administrator, an 
Inspection and Monitoring Plan explaining your compliance approach 90 
calendar days prior to beginning operation of your new POTW or by date 
180 days after the final rule is published in the Federal Register, 
whichever is later.
    (g) To comply with the pretreatment requirements specified in Sec.  
63.1586(d), you must submit the reports required by Sec.  403.12 this 
chapter.

General Requirements

Sec.  63.1591  What are my notification requirements?

    (a) You must submit an initial notification as required in Sec.  
63.9(b).
    (b) You must submit a notification of compliance status as required 
in Sec.  63.9(h), as specified below:
    (1) If you comply with Sec.  63.1586(a) or (c) by meeting the 
applicable HAP fraction emitted standard, submission of the Inspection 
and Monitoring Plan as required in Sec.  63.1588(c) and Sec.  
63.1590(e) and (f), as applicable, meets the requirement for submitting 
a notification of compliance status report in Sec.  63.9(h).
    (2) If you comply with Sec.  63.1586(b) and use covers on the 
emission points and route air in the headspace underneath the cover to 
a control device, you must submit a notification of compliance status 
as specified in Sec.  63.9(h) that includes a description of the POTW 
treatment units and installed covers, as well as the information 
required for control devices including the performance test results.
    (c) You must notify the Administrator, within 30 calendar days of 
discovering that you are out of compliance with an applicable 
requirement of this subpart, including the following:
    (1) The HAP fraction emitted standard as specified in Sec.  
63.1586(a) or (c), as applicable.
    (2) The requirement to route the air in the headspace underneath 
the cover of all units equipped with covers, except primary clarifiers, 
to a control device as specified in Sec.  63.1586(b).
    (3) The requirement to develop and implement a pretreatment program 
as specified in Sec.  63.1586(d).
    (4) The requirement to operate and maintain the affected source as 
specified in Sec.  63.1586(e).
    (5) The requirement to inspect covers annually and repair defects 
as specified in Sec.  63.1588(a).
    (6) The requirement to comply with the inspection and monitoring

[[Page 95393]]

requirements of Sec.  63.695(c) as specified in Sec.  63.1588(b).
    (7) The procedures specified in an Inspection and Monitoring Plan 
prepared as specified in Sec.  63.1588(c).
    (8) The requirements specified in an appropriate NESHAP for which 
the Group 1 POTW treats regulated industrial waste as specified in 
Sec.  63.1583(a) or (b), as applicable.

Sec.  63.1592  Which General Provisions apply to my POTW?

    (a) Table 1 to this subpart lists the General Provisions (40 CFR 
part 63, subpart A) that do and do not apply to POTW.
    (b) Unless a permit is otherwise required by law, the owner or 
operator of a Group 1 POTW that is not a major source is exempt from 
the permitting requirements established by 40 CFR part 70.

Sec.  63.1593   [Reserved]

Sec.  63.1594  Who enforces this subpart?

    (a) This subpart can be implemented and enforced by the U.S. EPA, 
or a delegated authority such as the applicable state, local, or tribal 
agency. If the U.S. EPA Administrator has delegated authority to a 
state, local, or tribal agency, then that agency, in addition to the 
U.S. EPA, has the authority to implement and enforce this subpart. 
Contact the applicable U.S. EPA Regional Office to find out if 
implementation and enforcement of this subpart is delegated to a state, 
local, or tribal agency.
    (b) In delegating implementation and enforcement authority of this 
subpart to a state, local, or tribal agency under subpart E of this 
part, the authorities listed in (b)(1) through (5) of this section are 
retained by the Administrator of U.S. EPA and cannot be delegated to 
the state, local, or tribal agency.
    (1) Approval of alternatives to the requirements in Sec. Sec.  
63.1580, 63.1583, and 63.1586 through 63.1588.
    (2) Approval of major alternatives to test methods under Sec.  
63.7(e)(2)(ii) and (f), as defined in Sec.  63.90, and as required in 
this subpart.
    (3) Approval of major alternatives to monitoring under Sec.  
63.8(f), as defined in Sec.  63.90, and as required in this subpart.
    (4) Approval of major alternatives to recordkeeping and reporting 
under Sec.  63.10(f), as defined in Sec.  63.90, and as required in 
this subpart.
    (5) Approval of an alternative to any electronic reporting to the 
EPA required by this subpart.

Sec.  63.1595   List of definitions.

    Affected source means a POTW that has a design capacity of 5 
million gallons of wastewater per day or more, treats industrial 
wastewater, and is either a Group 1 POTW or a major source that is a 
Group 2 POTW.
    Cover means a device that prevents or reduces air pollutant 
emissions to the atmosphere by forming a continuous barrier over the 
waste material managed in a treatment unit. A cover may have openings 
(such as access hatches, sampling ports, gauge wells) that are 
necessary for operation, inspection, maintenance, and repair of the 
treatment unit on which the cover is used. A cover may be a separate 
piece of equipment which can be detached and removed from the treatment 
unit, or a cover may be formed by structural features permanently 
integrated into the design of the treatment unit. The cover and its 
closure devices must be made of suitable materials that will prevent 
exposure of the waste material to the atmosphere and will maintain the 
integrity of the cover and its closure devices throughout its intended 
service life.
    Existing source or Existing POTW means a POTW that commenced 
construction on or before December 1, 1998, and has not been 
reconstructed after December 1, 1998.
    Fraction emitted means the fraction of the mass of HAP entering the 
POTW wastewater treatment plant which is emitted prior to secondary 
treatment.
    Group 1 POTW means a POTW that accepts a waste stream regulated by 
another NESHAP and provides treatment and controls as an agent for the 
industrial discharger. The industrial discharger complies with its 
NESHAP by using the treatment and controls located at the POTW. For 
example, an industry discharges its benzene-containing waste stream to 
the POTW for treatment to comply with 40 CFR part 61, subpart FF--
National Emission Standard for Benzene Waste Operations. This 
definition does not include POTW treating waste streams not 
specifically regulated under another NESHAP.
    Group 2 POTW means a POTW that does not meet the definition of a 
Group 1 POTW. A Group 2 POTW can treat a waste stream that is either:
    (1) Not specifically regulated by another NESHAP, or
    (2) from an industrial facility that complies with the specific 
wastewater requirements in their applicable NESHAP prior to discharging 
the waste stream to the POTW collection system.
    New source or New POTW means any POTW that commenced construction 
or reconstruction after December 1, 1998.
    Publicly owned treatment works (POTW) means a treatment works, as 
that term is defined by section 112(e)(5) of the Clean Air Act, which 
is owned by a municipality (as defined by section 502(4) of the Clean 
Water Act), a state, an intermunicipal or interstate agency, or any 
department, agency, or instrumentality of the federal government. This 
definition includes any intercepting sewers, outfall sewers, sewage 
collection systems, pumping, power, and other equipment. The wastewater 
treated by these facilities is generated by industrial, commercial, and 
domestic sources. As used in this regulation, the term POTW refers to 
both any publicly owned treatment works which is owned by a state, 
municipality, or intermunicipal or interstate agency and, therefore, 
eligible to receive grant assistance under the Subchapter II of the 
Clean Water Act, and any federally owned treatment works as that term 
is described in section 3023 of the Solid Waste Disposal Act.
    POTW treatment plant means that portion of the POTW which is 
designed to provide treatment (including recycling and reclamation) of 
municipal sewage and industrial waste.
    Secondary treatment means treatment processes, typically 
biological, designed to reduce the concentrations of dissolved and 
colloidal organic matter in wastewater.
    Waste and wastewater means a material, or spent or used water or 
waste, generated from residential, industrial, commercial, mining, or 
agricultural operations or from community activities that contain 
dissolved or suspended matter, and that is discarded, discharged, or is 
being accumulated, stored, or physically, chemically, thermally, or 
biologically treated in a publicly owned treatment works.

   Table 1 to Subpart VVV of Part 63--Applicability of 40 CFR Part 63
                    General Provisions to Subpart VVV
------------------------------------------------------------------------
                                 Applicable to
 General provisions reference     subpart VVV          Explanation
------------------------------------------------------------------------
Sec.   63.1..................  ................  Applicability.

[[Page 95394]]

 
Sec.   63.1(a)(1)............  Yes.............  Terms defined in the
                                                  Clean Air Act.
Sec.   63.1(a)(2)............  Yes.............  General applicability
                                                  explanation.
Sec.   63.1(a)(3)............  Yes.............  Cannot diminish a
                                                  stricter NESHAP.
Sec.   63.1(a)(4)............  Yes.............  Not repetitive. Doesn't
                                                  apply to section
                                                  112(r).
Sec.   63.1(a)(5)............  Yes.............  Section reserved.
Sec.   63.1(a)(6)-(8)........  Yes.............  Contacts and
                                                  authorities.
Sec.   63.1(a)(9)............  Yes.............  Section reserved.
Sec.   63.1(a)(10)...........  Yes.............  Time period definition.
Sec.   63.1(a)(11)...........  Yes.............  Postmark explanation.
Sec.   63.1(a)(12)-(14)......  Yes.............  Time period changes.
                                                  Regulation conflict.
                                                  Force and effect of
                                                  subpart A.
Sec.   63.1(b)(1)............  Yes.............  Initial applicability
                                                  determination of
                                                  subpart A.
Sec.   63.1(b)(2)............  Yes.............  Section reserved.
Sec.   63.1(b)(3)............  No..............  Subpart VVV specifies
                                                  recordkeeping of
                                                  records of
                                                  applicability
                                                  determination.
Sec.   63.1(c)(1)............  Yes.............  Requires compliance
                                                  with both subpart A
                                                  and subpart VVV.
Sec.   63.1(c)(2)(i).........  No..............  State options regarding
                                                  title V permit. Unless
                                                  required by the State,
                                                  area sources subject
                                                  to subpart VVV are
                                                  exempted from
                                                  permitting
                                                  requirements.
Sec.   63.1(c)(2)(ii)-(iii)..  No..............  State options regarding
                                                  title V permit.
Sec.   63.1(c)(3)............  Yes.............  Section reserved.
Sec.   63.1(c)(4)............  Yes.............  Extension of
                                                  compliance.
Sec.   63.1(c)(5)............  No..............  Subpart VVV addresses
                                                  area sources becoming
                                                  major due to increase
                                                  in emissions.
Sec.   63.1(d)...............  Yes.............  Section reserved.
Sec.   63.1(e)...............  Yes.............  Title V permit before a
                                                  relevant standard is
                                                  established.
Sec.   63.2..................  Yes.............  Definitions.
Sec.   63.3..................  Yes.............  Units and
                                                  abbreviations.
Sec.   63.4..................  ................  Prohibited activities
                                                  and circumvention.
Sec.   63.4(a)(1)-(3)........  Yes.............  Prohibits operation in
                                                  violation of subpart
                                                  A.
Sec.   63.4(a)(4)............  Yes.............  Section reserved.
Sec.   63.4(a)(5)............  Yes.............  Compliance dates.
Sec.   63.4(b)...............  Yes.............  Circumvention.
Sec.   63.4(c)...............  Yes.............  Severability.
Sec.   63.5..................  ................  Preconstruction review
                                                  and notification
                                                  requirements.
Sec.   63.5(a)(1)............  Yes.............  Construction and
                                                  reconstruction.
Sec.   63.5(a)(2)............  Yes.............  New source--effective
                                                  dates.
Sec.   63.5(b)(1)............  Yes.............  New sources subject to
                                                  relevant standards.
Sec.   63.5(b)(2)............  Yes.............  Section reserved.
Sec.   63.5(b)(3)............  Yes.............  No new major sources
                                                  without Administrator
                                                  approval.
Sec.   63.5(b)(4)............  Yes.............  New major source
                                                  notification.
Sec.   63.5(b)(5)............  Yes.............  New major sources must
                                                  comply.
Sec.   63.5(b)(6)............  Yes.............  New equipment added
                                                  considered part of
                                                  major source.
Sec.   63.5(c)...............  Yes.............  Section reserved.
Sec.   63.5(d)(1)............  Yes.............  Implementation of
                                                  section 112(I)(2)--
                                                  application of
                                                  approval of new source
                                                  construction.
Sec.   63.5(d)(2)............  Yes.............  Application for
                                                  approval of
                                                  construction for new
                                                  sources listing and
                                                  describing planned air
                                                  pollution control
                                                  system.
Sec.   63.5(d)(3)............  Yes.............  Application for
                                                  reconstruction.
Sec.   63.5(d)(4)............  Yes.............  Administrator may
                                                  request additional
                                                  information.
Sec.   63.5(e)...............  Yes.............  Approval of
                                                  reconstruction.
Sec.   63.5(f)(1)............  Yes.............  Approval based on State
                                                  review.
Sec.   63.5(f)(2)............  Yes.............  Application deadline.
Sec.   63.6..................  ................  Compliance with
                                                  standards and
                                                  maintenance
                                                  requirements.
Sec.   63.6(a)...............  Yes.............  Applicability of
                                                  compliance with
                                                  standards and
                                                  maintenance
                                                  requirements.
Sec.   63.6(b)...............  Yes.............  Compliance dates for
                                                  new and reconstructed
                                                  sources.
Sec.   63.6(c)...............  Yes.............  Compliance dates for
                                                  existing sources apply
                                                  to existing Group 1
                                                  POTW.
Sec.   63.6(d)...............  Yes.............  Section reserved.
Sec.   63.6(e)...............  Yes, except as    Operation and
                                noted.            maintenance
                                                  requirements apply to
                                                  new sources.
Sec.   63.6(e)(1)(i).........  No..............  General duty; See Sec.
                                                   63.1583(d) and Sec.
                                                  63.1586(e) for general
                                                  duty requirements.
Sec.   63.6(e)(1)(ii)........  No..............  Requirement to correct
                                                  malfunctions.
Sec.   63.6(e)(3)............  No..............  SSM plans are not
                                                  required.
Sec.   63.6(f), except as      Yes, except as    Compliance with non-
 noted.                         noted.            opacity emission
                                                  standards applies to
                                                  new sources.
Sec.   63.6(f)(1)............  No..............  Standards apply at all
                                                  times.
Sec.   63.6(g)...............  Yes.............  Use of alternative non-
                                                  opacity emission
                                                  standards applies to
                                                  new sources.
Sec.   63.6(h)...............  No..............  POTW do not typically
                                                  have visible
                                                  emissions.
Sec.   63.6(i)...............  Yes.............  Extension of compliance
                                                  with emission
                                                  standards applies to
                                                  new sources.
Sec.   63.6(j)...............  Yes.............  Presidential exemption
                                                  from compliance with
                                                  emission standards.
Sec.   63.7..................  ................  Performance testing
                                                  requirements.
Sec.   63.7(a)...............  Yes.............  Performance testing is
                                                  required for new
                                                  sources.

[[Page 95395]]

 
Sec.   63.7(b)...............  Yes.............  New sources must notify
                                                  the Administrator of
                                                  intention to conduct
                                                  performance testing.
Sec.   63.7(c)...............  Yes.............  New sources must comply
                                                  with quality assurance
                                                  program requirements.
Sec.   63.7(d)...............  Yes.............  New sources must
                                                  provide performance
                                                  testing facilities at
                                                  the request of the
                                                  Administrator.
Sec.   63.7(e)...............  Yes, except as    Requirements for
                                noted.            conducting performance
                                                  tests apply to new
                                                  sources.
Sec.   63.7(e)(1)............  No..............  The performance testing
                                                  provisions of Sec.
                                                  63.694 for control
                                                  devices are
                                                  incorporated by
                                                  reference into subpart
                                                  DD of this part.
Sec.   63.7(f)...............  Yes.............  New sources may use an
                                                  alternative test
                                                  method.
Sec.   63.7(g)...............  Yes.............  Requirements for data
                                                  analysis,
                                                  recordkeeping, and
                                                  reporting associated
                                                  with performance
                                                  testing apply to new
                                                  sources.
Sec.   63.7(h)...............  Yes.............  New sources may request
                                                  a waiver of
                                                  performance tests.
Sec.   63.8..................  ................  Monitoring
                                                  requirements.
Sec.   63.8(a)...............  Yes.............  Applicability of
                                                  monitoring
                                                  requirements.
Sec.   63.8(b)...............  Yes.............  Monitoring shall be
                                                  conducted by new
                                                  sources.
Sec.   63.8(c)...............  Yes, except as    New sources shall
                                noted.            operate and maintain
                                                  continuous monitoring
                                                  systems (CMS).
Sec.   63.8(c)(1)(i).........  No..............  See Sec.   63.1583(d)
                                                  for general duty
                                                  requirement with
                                                  respect to minimizing
                                                  emissions and
                                                  continuous monitoring
                                                  requirements.
Sec.   63.8(c)(1)(iii).......  No..............  See the applicable CMS
                                                  quality control
                                                  requirements under
                                                  Sec.   63.8(c) and
                                                  (d).
Sec.   63.8(d)...............  Yes, except as    New sources must
                                noted.            develop and implement
                                                  a CMS quality control
                                                  program.
Sec.   63.8(d)(3)............  No..............  The owner or operator
                                                  must keep these
                                                  written procedures on
                                                  record for the life of
                                                  the affected source or
                                                  until the affected
                                                  source is no longer
                                                  subject to the
                                                  provisions of this
                                                  part, and make them
                                                  available for
                                                  inspection, upon
                                                  request, by the
                                                  Administrator. If the
                                                  performance evaluation
                                                  plan is revised, the
                                                  owner or operator must
                                                  keep previous (i.e.,
                                                  superseded) versions
                                                  of the performance
                                                  evaluation plan on
                                                  record to be made
                                                  available for
                                                  inspection, upon
                                                  request, by the
                                                  Administrator, for a
                                                  period of 5 years
                                                  after each revision to
                                                  the plan. The program
                                                  of corrective action
                                                  should be included in
                                                  the plan required
                                                  under Sec.
                                                  63.8(d)(2).
Sec.   63.8(e)...............  Yes.............  New sources may be
                                                  required to conduct a
                                                  performance evaluation
                                                  of CMS.
Sec.   63.8(f)...............  Yes.............  New sources may use an
                                                  alternative monitoring
                                                  method.
Sec.   63.8(g)...............  Yes.............  Requirements for
                                                  reduction of
                                                  monitoring data.
Sec.   63.9..................  ................  Notification
                                                  requirements.
Sec.   63.9(a)...............  Yes.............  Applicability of
                                                  notification
                                                  requirements.
Sec.   63.9(b)...............  Yes, except as    Initial Notification
                                noted.            due February 23, 2000
                                                  or 60 days after
                                                  becoming subject to
                                                  this subpart.
Sec.   63.9(c)...............  Yes.............  Request for extension
                                                  of compliance with
                                                  subpart VVV.
Sec.   63.9(d)...............  Yes.............  Notification that
                                                  source is subject to
                                                  special compliance
                                                  requirements as
                                                  specified in Sec.
                                                  63.6(b)(3) and (4).
Sec.   63.9(e)...............  Yes.............  Notification of
                                                  performance test.
Sec.   63.9(f)...............  No..............  POTW do not typically
                                                  have visible
                                                  emissions.
Sec.   63.9(g)...............  Yes.............  Additional notification
                                                  requirements for
                                                  sources with
                                                  continuous emission
                                                  monitoring systems.
Sec.   63.9(h)...............  Yes, except as    Notification of
                                noted.            compliance status when
                                                  the source becomes
                                                  subject to subpart
                                                  VVV. See exceptions in
                                                  Sec.   63.1591(b).
Sec.   63.9(i)...............  Yes.............  Adjustments to time
                                                  periods or postmark
                                                  deadlines or submittal
                                                  and review of required
                                                  communications.
Sec.   63.9(j)...............  Yes.............  Change of information
                                                  already provided to
                                                  the Administrator.
Sec.   63.10.................  ................  Recordkeeping and
                                                  reporting
                                                  requirements.
Sec.   63.10(a)..............  Yes.............  Applicability of
                                                  notification and
                                                  reporting
                                                  requirements.
Sec.   63.10(b)(1)-(2).......  Yes, except as    General recordkeeping
                                noted.            requirements.
Sec.   63.10(b)(2)(i)........  No..............  Recordkeeping for
                                                  occurrence and
                                                  duration of startup
                                                  and shutdown.
Sec.   63.10(b)(2)(ii).......  No..............  Recordkeeping for
                                                  failure to meet a
                                                  standard, see Sec.
                                                  63.696.
Sec.   63.10(b)(2)(iii)......  Yes.............  Maintenance records.
Sec.   63.10(b)(2)(iv).......  No..............  Actions taken to
                                                  minimize emissions
                                                  during SSM.
Sec.   63.10(b)(2)(v)........  No..............  Actions taken to
                                                  minimize emissions
                                                  during SSM.
Sec.   63.10(b)(2)(vi).......  Yes.............  Recordkeeping for CMS
                                                  malfunctions.
Sec.   63.10(b)(2)(vii)-(ix).  Yes.............  Other CMS requirements.
Sec.   63.10(b)(3)...........  No..............  Recording requirement
                                                  for applicability
                                                  determination.
Sec.   63.10(c)..............  Yes, except as    Additional
                                noted.            recordkeeping
                                                  requirements for
                                                  sources with
                                                  continuous monitoring
                                                  systems.
Sec.   63.10(c)(8)...........  No..............  See Sec.   63.696(h)
                                                  for recordkeeping of
                                                  (1) date, time and
                                                  duration; (2) listing
                                                  of affected source or
                                                  equipment, and an
                                                  estimate of the volume
                                                  of each regulated
                                                  pollutant emitted over
                                                  the standard; and (3)
                                                  actions to minimize
                                                  emissions and correct
                                                  the failure.

[[Page 95396]]

 
Sec.   63.10(c)(7)...........  No..............  See Sec.   63.696(h)
                                                  for recordkeeping of
                                                  (1) date, time and
                                                  duration; (2) listing
                                                  of affected source or
                                                  equipment, and an
                                                  estimate of the volume
                                                  of each regulated
                                                  pollutant emitted over
                                                  the standard; and (3)
                                                  actions to minimize
                                                  emissions and correct
                                                  the failure.
Sec.   63.10(c)(15)..........  No..............  Use of SSM plan.
Sec.   63.10(d)..............  Yes, except as    General reporting
                                noted.            requirements.
Sec.   63.10(d)(5)...........  No..............  See Sec.   63.697(b)
                                                  for malfunction
                                                  reporting
                                                  requirements.
Sec.   63.10(e)..............  Yes.............  Additional reporting
                                                  requirements for
                                                  sources with
                                                  continuous monitoring
                                                  systems.
Sec.   63.10(f)..............  Yes.............  Waiver of recordkeeping
                                                  and reporting
                                                  requirements.
Sec.   63.11.................  Yes.............  Control device and
                                                  equipment leak work
                                                  practice requirements.
Sec.   63.11(a) and (b)......  Yes.............  If a new source uses
                                                  flares to comply with
                                                  the requirements of
                                                  subpart VVV, the
                                                  requirements of Sec.
                                                  63.11 apply.
Sec.   63.11(c), (d) and (e).  Yes.............  Alternative work
                                                  practice for equipment
                                                  leaks.
Sec.   63.12.................  Yes.............  State authority and
                                                  designation.
Sec.   63.13.................  Yes.............  Addresses of State air
                                                  pollution control
                                                  agencies and EPA
                                                  Regional Offices.
Sec.   63.14.................  Yes.............  Incorporation by
                                                  reference.
Sec.   63.15.................  Yes.............  Availability of
                                                  information and
                                                  confidentiality.
------------------------------------------------------------------------

  Table 2 to Subpart VVV of Part 63--Compliance Dates and Requirements
------------------------------------------------------------------------
                                                      And the owner or
    If the construction/        Then the owner or      operators must
reconstruction date is . . .     operators must     achieve compliance .
                                comply with . . .            . .
------------------------------------------------------------------------
Group 1 POTW:
    (1) After [date of        (i) New source        Upon initial
     publication of the        requirements in       startup.
     final rule in the         Sec.  Sec.
     Federal Register].        63.1583(b);
                               63.1586(b) or (c);
                               63.1586(d); and
                               63.1588 through
                               63.1591.
    (2) After December 1,     (i) New source        (i) Upon initial
     1998 but on or before     requirements in       startup through the
     [date of publication of   Sec.   63.1583(b)     date 12 months
     the final rule in the     but instead of        after the final
     Federal Register].        complying with both   rule is published
                               requirements, you     in the Federal
                               must comply with      Register.
                               the most stringent
                               requirement \1\.
                              (ii) New source       (ii) On or before
                               requirements in       date 12 months
                               Sec.  Sec.            after the final
                               63.1586(b) or (c);    rule is published
                               63.1586(d); and       in the Federal
                               63.1588 through       Register.
                               63.1591.
    (3) On or before          (i) Existing source   (i) By the
     December 1, 1998.         requirements in       compliance date
                               Sec.   63.1583(a)     specified in the
                               but instead of        other applicable
                               complying with both   NESHAP.
                               requirements, you
                               must comply with
                               only the other
                               applicable NESHAP.
                              (ii) Existing source  (ii) On or before
                               requirements in       date 12 months
                               Sec.  Sec.            after the final
                               63.1583(a);           rule is published
                               63.1586(a) and (d);   in the Federal
                               and 63.1588 through   Register.
                               63.1591.
Group 2 POTW:
    (4) After [date of        (i) New source        Upon initial
     publication of the        requirements in       startup.
     final rule in the         Sec.  Sec.
     Federal Register].        63.1586(b) or (c);
                               63.1586(d); and
                               63.1588 through
                               63.1591.
    (5) After December 1,     (i) New source        (i) Upon initial
     1998 but on or before     requirements in       startup through the
     [date of publication of   Sec.   63.1586(b)     date 12 months
     the final rule in the     or (c) \1\.           after the final
     Federal Register].                              rule is published
                                                     in the Federal
                                                     Register.
                              (ii) New source       (ii) On or before
                               requirements in       date 12 months
                               Sec.  Sec.            after the final
                               63.1586(b) or (c);    rule is published
                               63.1586(d); and       in the Federal
                               63.1588 through       Register.
                               63.1591.
    (6) On or before          (i) Existing source   On or before date 12
     December 1, 1998.         requirements in       months after the
                               Sec.  Sec.            final rule is
                               63.1586(a) and (d);   published in the
                               and 63.1588 through   Federal Register.
                               63.1591.
------------------------------------------------------------------------
\1\ Note: This represents the requirements in the original 1999 NESHAP,
  which are applicable until 12-months after the final rule is published
  in the Federal Register. During those 12-months, you must transition
  to the new requirements in Table 2 (2)(ii) and (5)(ii) for Group 1 and
  Group 2 POTW, respectively.

[FR Doc. 2016-30471 Filed 12-23-16; 8:45 am]
 BILLING CODE 6560-50-P