[Federal Register Volume 85, Number 157 (Thursday, August 13, 2020)]
[Rules and Regulations]
[Pages 49434-49469]
[FR Doc No: 2020-12725]

Vol. 85

Thursday,

No. 157

August 13, 2020

Part II

Environmental Protection Agency

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40 CFR Part 63

National Emission Standards for Hazardous Air Pollutants: Plywood and
Composite Wood Products Residual Risk and Technology Review; Final Rule

Federal Register / Vol. 85, No. 157 / Thursday, August 13, 2020 /
Rules and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2016-0243; FRL-10009-65-OAR]
RIN 2060-AO66

National Emission Standards for Hazardous Air Pollutants: Plywood
and Composite Wood Products Residual Risk and Technology Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This action finalizes the residual risk and technology review
(RTR) conducted for the Plywood and Composite Wood Products (PCWP)
source category regulated under national emission standards for
hazardous air pollutants (NESHAP). In addition, the EPA is taking final
action addressing periods of startup, shutdown and malfunction (SSM);
adding electronic reporting; adding repeat emissions testing; and
making technical and editorial changes. These final amendments include
no revisions to the numerical emission limits in the rule based on the
RTR. While the amendments do not result in reductions of emissions of
hazardous air pollutants (HAP), this action results in improved
monitoring, compliance, and implementation of the rule.

DATES: This final rule is effective on August 13, 2020. The
incorporation by reference of certain publications listed in the rule
is approved by the Director of the Federal Register as of August 13,
2020. The incorporation by reference of certain other publications
listed in the rule was approved by the Director of the Federal Register
as of February 16, 2006.

ADDRESSES: The U.S. Environmental Protection Agency (EPA) has
established a docket for this action under Docket ID No. EPA-HQ-OAR-
2016-0243. All documents in the docket are listed on the https://www.regulations.gov/ website. Although listed, some information is not
publicly available, e.g., Confidential Business Information or other
information whose disclosure is restricted by statute. Certain other
material, such as copyrighted material, is not placed on the internet
and will be publicly available only in hard copy form. Publicly
available docket materials are available electronically through https://www.regulations.gov/. Out of an abundance of caution for members of
the public and our staff, the EPA Docket Center and Reading Room was
closed to public visitors on March 31, 2020, to reduce the risk of
transmitting COVID-19. Our Docket Center staff will continue to provide
remote customer service via email, phone, and webform. There is a
temporary suspension of mail delivery to the EPA, and no hand
deliveries are currently accepted. For further information and updates
on EPA Docket Center services and the current status, please visit us
online at https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: For questions about this final action,
contact Ms. Katie Hanks, Sector Policies and Programs Division (E143-
03), Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina 27711;
telephone number:<PHONE_NUMBER>; fax number:<PHONE_NUMBER>; and email
address<EMAIL_ADDRESS>For specific information regarding the
risk modeling methodology, contact Mr. James Hirtz, 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:<PHONE_NUMBER>;
fax number:<PHONE_NUMBER>; and email address<EMAIL_ADDRESS>For
information about the applicability of the NESHAP to a particular
entity, contact Mr. John Cox, Office of Enforcement and Compliance
Assurance, U.S. Environmental Protection Agency, WJC South Building,
1200 Pennsylvania Ave. NW, Washington, DC 20460; telephone number:
(202) 564-1395; and email address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:
    Preamble acronyms and abbreviations. Multiple acronyms and terms
are used 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 level
CAA Clean Air Act
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CEMS continuous emission monitoring systems
CFR Code of Federal Regulations
CMS continuous monitoring systems
EAV equivalent annualized value
EPA Environmental Protection Agency
ERT Electronic Reporting Tool
HAP hazardous air pollutants(s)
HQ hazard quotient
ICR Information Collection Request
km kilometer
MACT maximum achievable control technology
NESHAP national emission standards for hazardous air pollutants
NTTAA National Technology Transfer and Advancement Act
OMB Office of Management and Budget
OSHA Occupational Safety and Health Administration
PCWP Plywood and Composite Wood Products
PDF portable document format
PRA Paperwork Reduction Act
PV present value
RATA relative accuracy test audit
RCO regenerative catalytic oxidizer
REL recommended exposure limit
RFA Regulatory Flexibility Act
RIN Regulatory Information Number
RTC Response to Comments
RTO regenerative thermal oxidizer
RTR residual risk and technology review
SSM startup, shutdown, and malfunction
the Court United States Court of Appeals for the District of
Columbia Circuit
TOSHI target organ-specific hazard index
tpy tons per year
UMRA Unfunded Mandates Reform Act

    Background information. On September 6, 2019, the EPA proposed
revisions to the PCWP NESHAP based on our RTR. See 84 FR 47074. In this
action, the EPA is finalizing decisions and revisions for the rule. We
summarize some of the more significant comments we timely received
regarding the proposed rulemaking and provide summaries of our
responses in this preamble. A summary of all public comments on the
proposal and the EPA's specific responses to those comments is
available in the Response to Comments (RTC) document, National Emission
Standards for Hazardous Air Pollutants: Plywood and Composite Wood
Products (40 CFR part 63, subpart DDDD) Residual Risk and Technology
Review, Final Amendments, Responses to Public Comments on September 6,
2019 Proposal, Docket ID No. EPA-HQ-OAR-2016-0243. A ``track changes''
version of the regulatory language that incorporates the changes in
this action is available in the docket.
    Organization of this document. The information in this preamble is
organized as follows:

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related
information?
    C. Judicial Review and Administrative Reconsideration
II. Background
    A. What is the statutory authority for this action?
    B. What is the PCWP source category and how does the NESHAP
regulate HAP emissions from the source category?
    C. What changes did we propose for the PCWP source category in
our September 6, 2019, proposal?
III. What is included in this final rule?
    A. What are the final rule amendments based on the risk review
for the PCWP source category?

    B. What are the final rule amendments based on the technology
review for the PCWP source category?
    C. What are the final rule amendments addressing emissions
during periods of SSM?
    D. What other changes have been made to the NESHAP?
    E. What are the effective and compliance dates of the standards?
IV. What is the rationale for our final decisions and amendments for
the PCWP source category?
    A. Residual Risk Review for the PCWP Source Category
    B. Technology Review for the PCWP Source Category
    C. SSM Provisions
    D. Electronic Reporting
    E. Repeat Emissions Testing
    F. Biofilter Bed Temperature
    G. Thermocouple Calibration
    H. Non-HAP Coating Definition
    I. Technical and Editorial Changes
    J. Compliance Dates
V. Summary of Cost, Environmental, and Economic Impacts and
Additional Analyses Conducted
    A. What are the affected facilities?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
    F. What analysis of environmental justice did we conduct?
    G. What analysis of children's environmental health did we
conduct?
VI. Statutory and Executive Order Reviews
    A. Executive Orders 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Executive Order 13771: Reducing Regulations and Controlling
Regulatory Cost
    C. Paperwork Reduction Act (PRA)
    D. Regulatory Flexibility Act (RFA)
    E. Unfunded Mandates Reform Act (UMRA)
    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    H. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
    I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
    J. National Technology Transfer and Advancement Act (NTTAA) and
1 CFR part 51
    K. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations
    L. Congressional Review Act (CRA)

I. General Information

A. Does this action apply to me?

    Regulated entities. Categories and entities potentially regulated
by this action are shown in Table 1 of this preamble.

 Table 1--NESHAP and Industrial Source Categories Affected by This Final
                                 Action
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       NESHAP and source category                 NAICS \1\ code
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National Emission Standards for          321999, 321211, 321212, 321219,
 Hazardous Air Pollutants: Plywood and    321213.
 Composite Wood Products.
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\1\ North American Industry Classification System.

    Table 1 of this preamble is not intended to be exhaustive, but
rather to provide a guide for readers regarding entities likely to be
affected by the final action for the source category listed. To
determine whether your facility is affected, you should examine the
applicability criteria in the appropriate NESHAP. If you have any
questions regarding the applicability of any aspect of this NESHAP,
please contact the appropriate person listed in the preceding FOR
FURTHER INFORMATION CONTACT section of this preamble.

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 final action will also be available on the internet. Following
signature by the EPA Administrator, the EPA will post a copy of this
final action at: https://www.epa.gov/stationary-sources-air-pollution/plywood-and-composite-wood-products-manufacture-national-emission.
Following publication in the Federal Register, the EPA will post the
Federal Register version and key technical documents at this same
website.
    Additional information is available on the RTR website at https://www.epa.gov/stationary-sources-air-pollution/risk-and-technology-review-national-emissions-standards-hazardous. This information
includes an overview of the RTR program and links to project websites
for the RTR source categories.

C. Judicial Review and Administrative Reconsideration

    Under Clean Air Act (CAA) section 307(b)(1), judicial review of
this final action is available only by filing a petition for review in
the United States Court of Appeals for the District of Columbia Circuit
(the Court) by October 13, 2020. Under CAA section 307(b)(2), the
requirements established by this final rule may not be challenged
separately in any civil or criminal proceedings brought by the EPA to
enforce the requirements.
    Section 307(d)(7)(B) of the CAA further provides that only an
objection to a rule or procedure which was raised with reasonable
specificity during the period for public comment (including any public
hearing) may be raised during judicial review. This section also
provides a mechanism for the EPA to reconsider the rule if the person
raising an objection can demonstrate to the Administrator that it was
impracticable to raise such objection within the period for public
comment or if the grounds for such objection arose after the period for
public comment (but within the time specified for judicial review) and
if such objection is of central relevance to the outcome of the rule.
Any person seeking to make such a demonstration should submit a
Petition for Reconsideration to the Office of the Administrator, U.S.
EPA, Room 3000, WJC South Building, 1200 Pennsylvania Ave. NW,
Washington, DC 20460, with a copy to both the person(s) listed in the
preceding FOR FURTHER INFORMATION CONTACT section, and the Associate
General Counsel for the Air and Radiation Law Office, Office of General
Counsel (Mail Code 2344A), U.S. EPA, 1200 Pennsylvania Ave. NW,
Washington, DC 20460.

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, we must identify categories of sources emitting one or more of
the HAP listed in CAA section 112(b) and then promulgate technology-
based NESHAP for those sources. ``Major sources'' are those that emit,
or have the potential to emit, any single HAP at a rate of 10 tons per
year (tpy) or more, or 25 tpy or more of any combination of HAP. For
major sources,

these standards are commonly referred to as maximum achievable control
technology (MACT) standards and must reflect the maximum degree of
emission reductions of HAP achievable (after considering cost, energy
requirements, and non-air quality health and environmental impacts). In
developing MACT standards, CAA section 112(d)(2) directs the EPA to
consider the application of measures, processes, methods, systems, or
techniques, including, but not limited to, those that reduce the volume
of or eliminate HAP emissions through process changes, substitution of
materials, or other modifications; enclose systems or processes to
eliminate emissions; collect, capture, or treat HAP when released from
a process, stack, storage, or fugitive emissions point; are design,
equipment, work practice, or operational standards; or any combination
of the above.
    For these MACT standards, the statute specifies certain minimum
stringency requirements, which are referred to as MACT floor
requirements, and which may not be based on cost considerations. See
CAA section 112(d)(3). For new sources, the MACT floor cannot be less
stringent than the emission control achieved in practice by the best-
controlled similar source. The MACT standards for existing sources can
be less stringent than floors for new sources, but they cannot be less
stringent than the average emission 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 under CAA section 112(d)(2). We may establish
standards more stringent than the floor, based on the consideration of
the cost of achieving the emissions reductions, any non-air quality
health and environmental impacts, and energy requirements.
    In the second stage of the regulatory process, the CAA requires the
EPA to undertake two different analyses, which we refer to as the
technology review and the residual risk review. Under the technology
review, we must review the 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, pursuant to CAA section 112(d)(6). Under the residual risk
review, we must evaluate the risk to public health remaining after
application of the technology-based standards and revise the standards,
if necessary, to provide an ample margin of safety to protect public
health or to prevent, taking into consideration costs, energy, safety,
and other relevant factors, an adverse environmental effect. The
residual risk review is required within 8 years after promulgation of
the technology-based standards, pursuant to CAA section 112(f). In
conducting the residual risk review, if the EPA determines that the
current standards provide an ample margin of safety to protect public
health, it is not necessary to revise the MACT standards pursuant to
CAA section 112(f) and the EPA may readopt the MACT standards as
residual risk standards.\1\ For more information on the statutory
authority for this rule, see 84 FR 47074 (September 6, 2019).
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    \1\ The Court has affirmed this approach of implementing CAA
section 112(f)(2)(A): 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.'').
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B. What is the PCWP source category and how does the NESHAP regulate
HAP emissions from the source category?

    The EPA originally promulgated the PCWP NESHAP on July 30, 2004.
The standards are codified at 40 CFR part 63, subpart DDDD. The PCWP
industry consists of facilities engaged in the production of PCWP and/
or kiln-dried lumber. Plywood and composite wood products are
manufactured by bonding wood material (fibers, particles, strands,
etc.) or agricultural fiber, generally with resin under heat and
pressure, to form a structural panel or engineered wood product. PCWP
manufacturing facilities also include facilities that manufacture dry
veneer and lumber kilns located at any facility. PCWP include (but are
not limited to) plywood, veneer, particleboard, oriented strand board
(OSB), hardboard, fiberboard, medium density fiberboard, laminated
strand lumber, laminated veneer lumber, wood I-joists, kiln-dried
lumber, and glue-laminated beams. As noted in the preamble to the
proposed amendments, the PCWP source category covered by this MACT
standard includes 230 major source facilities: 93 PCWP facilities, 121
lumber mills, and 16 facilities that produce both PCWP and lumber.
    The affected source under the PCWP NESHAP is the collection of
dryers, refiners, blenders, formers, presses, board coolers, and other
process units associated with the manufacturing of PCWP. The NESHAP
contains several compliance options for process units subject to the
standards: (1) Installation and use of emissions control systems with
an efficiency of at least 90 percent; (2) production-based limits that
restrict HAP emissions per unit of product; and (3) emissions averaging
that allows control of emissions from a group of sources collectively
(at existing affected sources). These compliance options apply for the
following process units: Fiberboard mat dryer heated zones (at new
affected sources); green rotary dryers; hardboard ovens; press
predryers (at new affected sources); pressurized refiners; primary tube
dryers; secondary tube dryers; reconstituted wood product board coolers
(at new affected sources); reconstituted wood product presses; softwood
veneer dryer heated zones; rotary strand dryers; and conveyor strand
dryers (zone one at existing affected sources, and zones one and two at
new affected sources). In addition, the PCWP NESHAP includes work
practice standards for dry rotary dryers, hardwood veneer dryers,
softwood veneer dryers, veneer redryers, and group 1 miscellaneous
coating operations (defined in 40 CFR 63.2292).

C. What changes did we propose for the PCWP source category in our
September 6, 2019, proposal?

    On September 6, 2019, the EPA published a proposed rulemaking in
the Federal Register for the PCWP NESHAP, 40 CFR part 63, subpart DDDD,
that took into consideration the RTR analyses. In the proposed
rulemaking, we proposed revisions to the SSM provisions for the NESHAP
in order to ensure that they are consistent with the decision of the
Court in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), which
vacated two provisions in EPA's 40 CFR part 63, subpart A--General
Provisions, that exempted sources from the requirement to comply with
otherwise applicable CAA section 112(d) emission standards during
periods of SSM: 40 CFR 63.6(f)(1) and (h)(1). We also proposed various
other changes, including addition of electronic reporting requirements,
addition of repeat emissions testing requirements, revisions to
parameter monitoring requirements, and various technical and editorial
changes.

III. What is included in this final rule?

    This action finalizes the EPA's determinations pursuant to the RTR
provisions of CAA section 112 for the PCWP source category. This action
also finalizes other changes to the NESHAP, including SSM provisions,
electronic reporting, additional emissions testing requirements, and
technical and editorial changes.

A. What are the final rule amendments based on the risk review for the
PCWP source category?

    The EPA proposed no changes to the PCWP NESHAP based on the risk
review conducted pursuant to CAA section 112(f). We are finalizing our
proposed determination that risks from the PCWP source category are
acceptable, considering all of the health information and factors
evaluated, and also considering risk estimation uncertainty. We are
also finalizing our proposed determination that revisions to the
current standards are not necessary to reduce risk to an acceptable
level, to provide an ample margin of safety to protect public health,
or to prevent an adverse environmental effect. As discussed further in
section IV.A of this preamble, the EPA reviewed public comments and
data revisions submitted during the public comment period but none of
the information received affected our determinations. Therefore, we are
not requiring additional controls in order to reduce risks and, thus,
are not making any revisions to the existing standards under CAA
section 112(f)(2). Instead, we are readopting the existing standards
under CAA section 112(f)(2), while making other modifications under
other authorities unrelated to risk.

B. What are the final rule amendments based on the technology review
for the PCWP source category?

    We determined that there are no developments in practices,
processes, and control technologies that warrant revisions to the MACT
standards for this source category. In the proposal, the EPA noted a
development in resin systems used to produce PCWP at some facilities
but found that facilities generally have not altered their HAP emission
control strategies to date as a result of resin changes and that it is
not necessary, or supported based on available data, at this time, to
amend the current standards. The EPA considered comments received
during the public comment period regarding our technology review,
however, these comments contained no new data or other information that
affected our determinations. Therefore, we are not finalizing revisions
to the MACT standards under CAA section 112(d)(6). Section IV.B of this
preamble provides further details on our conclusion with respect to the
technology review.

C. What are the final rule amendments addressing emissions during
periods of SSM?

    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C.
Cir. 2008), the Court 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 (h)(1), holding that under section
302(k) of the CAA, emissions standards or limitations must be
continuous in nature and that the SSM exemption violates the CAA's
requirement that some CAA section 112 standards apply continuously.
    The EPA has eliminated the SSM exemption in this rule. Consistent
with Sierra Club v. EPA, the EPA has established standards in this rule
that apply at all times. The standards that apply during normal
operation have been extended to apply at all times including SSM in
most instances. However, in this final rule, the EPA has established
work practice standards for specific types of startup and shutdown
events as described in section IV.C of this preamble. The EPA has also
revised Table 10 of this rule (the General Provisions applicability
table) in several respects as is explained in more detail in section
IV.C of this preamble. For example, we have eliminated the
incorporation of the General Provisions' requirement that sources
develop SSM plans. We have also eliminated or revised certain
recordkeeping and reporting requirements that are related to the SSM
exemption as described in detail in the proposed rulemaking and
summarized again in section IV.C of this preamble.

D. What other changes have been made to the NESHAP?

    Other changes to the NESHAP include:
    1. Electronic reporting. As discussed at proposal, the EPA is
finalizing amendments to the reporting requirements in the rule to
require electronic reporting for notifications of compliance status,
compliance test reports, and semiannual reports. Electronic reporting
is discussed further in section IV.D of this preamble.
    2. Repeat emissions testing. As discussed at proposal, the EPA is
finalizing amendments to Table 7 to subpart DDDD of part 63 to require
repeat testing every 5 years for process units controlled with control
devices other than biofilters. The first of the 5-year repeat tests
will be required within 3 years of the effective date of the final
amendments. Repeat emissions testing is discussed further in section
IV.E of this preamble.
    3. Revisions to parameter monitoring requirements. As discussed at
proposal, the EPA is finalizing amendments to biofilter bed temperature
provisions in 40 CFR 63.2262(m)(1) and the thermocouple calibration
requirements in 40 CFR 63.2269. The biofilter bed temperature
provisions are discussed further in section IV.F of this preamble and
the thermocouple calibration requirements are discussed further in
section IV.G of this preamble.
    4. Revisions to the non-HAP coating definition. The EPA is
finalizing amendments to the non-HAP coating definition in 40 CFR
63.2292 with changes from the proposed revision. The non-HAP coating
definition is discussed further in section IV.H of this preamble.
    5. Technical and editorial changes. The EPA is finalizing technical
and editorial changes, as discussed further in section IV.I of this
preamble.

E. What are the effective and compliance dates of the standards?

    The revisions to the MACT standards being promulgated in this
action are effective on August 13, 2020. The compliance date of the
rule amendments for existing affected sources and other affected
sources that commenced construction or reconstruction on or before
September 6, 2019, is August 13, 2021. Affected sources that commenced
construction or reconstruction after September 6, 2019, are new
sources. New sources must comply with all of the standards immediately
upon the effective date of the standard, August 13, 2020, or upon
startup, whichever is later. All existing affected sources will have to
continue to meet the current requirements of the NESHAP until the
applicable compliance date of the amended rule.
    Section IV.D of this preamble discusses electronic reporting and a
semiannual reporting template that facilities must use within 1 year
after it is posted in the EPA's Compliance and Emissions Data Reporting
Interface (CEDRI). In addition, the EPA is finalizing new requirements
to conduct repeat performance testing every 5 years for facilities
using an add-on control system other than a biofilter (see section IV.E
of this preamble). The first of the repeat performance tests must be
conducted within 3 years after August 13, 2020, or within 60 months
following the previous performance test, whichever is later.

IV. What is the rationale for our final decisions and amendments for
the PCWP source category?

    For each issue, this section provides a description of what was
proposed and what is being finalized for the issue, the EPA's rationale
for the final decisions and amendments, and a summary of key comments
and responses. Comment summaries for all comments and the EPA's
specific responses can be found in the RTC document, available in
Docket ID No. EPA-HQ-OAR-2016-0243.

A. Residual Risk Review for the PCWP Source Category

1. What did we propose pursuant to CAA section 112(f) for the PCWP
source category?
    Pursuant to CAA section 112(f), the EPA conducted a risk review and
presented the results for the review, along with our proposed decisions
regarding risk acceptability and ample margin of safety, in the
September 6, 2019, proposed rulemaking for the PCWP source category (84
FR 47074). The results of the risk assessment are presented briefly in
Table 2 of this preamble and in the risk report titled Residual Risk
Assessment for the Plywood and Composite Wood Products Source Category
in Support of the 2019 Risk and Technology Review Proposed Rule, and
sections III and IV of the proposal preamble (84 FR 47074, September 6,
2019) available in the docket for this action.

                         Table 2--Inhalation Risk Assessment Summary for Plywood and Composite Wood Products Source Category \1\
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                                   Maximum individual      Population at increased   Annual cancer incidence       Maximum chronic           Maximum
                                    cancer risk (in 1     risk of cancer >= 1-in-1      (cases per year)         noncancer TOSHI \4\    screening  acute
                                      million) \3\                 million         ---------------------------------------------------- noncancer HQ \5\
                               ----------------------------------------------------      Based on . . .            Based on . . .      -----------------
   Number of facilities \2\          Based on . . .            Based on . . .      ----------------------------------------------------
                               ----------------------------------------------------
                                   Actual     Allowable      Actual     Allowable      Actual     Allowable      Actual     Allowable    Based on actual
                                 emissions    emissions    emissions    emissions    emissions    emissions    emissions    emissions    emissions level
                                   level        level        level        level        level        level        level        level
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233...........................           30           30      204,000      230,000         0.03         0.03          0.8          0.8  4 (REL) 0.2
                                                                                (AEGL-1)
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\1\ Based on actual and allowable emissions.
\2\ Number of facilities evaluated in the risk assessment. Includes 230 operating facilities subject to 40 CFR part 63, subpart DDDD, plus three
  existing facilities that are currently closed but maintain active operating permits.
\3\ Maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\4\ Maximum target organ-specific hazard index (TOSHI). The target organ with the highest TOSHI for the PCWP source category is the respiratory system.
\5\ The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop an array of hazard quotient (HQ)
  values. The acute HQ values shown use the lowest available acute threshold value, which in most cases is the recommended exposure limit (REL). When an
  HQ exceeds 1, the EPA also shows the HQ using the next lowest available acute dose-response value.

    For the risk assessment conducted at proposal, the EPA estimated
risks based on actual and allowable emissions from the PCWP source
category. The results for the PCWP source category indicated that both
the actual and allowable inhalation cancer risks to the individual most
exposed are below the presumptive limit of acceptability of 100-in-1
million. The residual risk assessment for the PCWP category estimated
cancer incidence rate at 0.03 cases per year (or one case every 33
years) based on both source category actual and allowable emissions.
The estimated inhalation cancer risk to the individual most exposed to
actual and allowable emissions from the source category was 30-in-1
million. The assessment showed that approximately 204,000 people faced
an increased cancer risk equal to or above 1-in-1 million from source
category actual emissions from 170 facilities. The number of people
exposed to a cancer risk greater than 10-in-1 million from source
category actual emissions is 650 people. The maximum chronic noncancer
TOSHI due to inhalation exposures was less than 1 (0.8) for actual and
allowable emissions from the source category. The results of the acute
non-cancer refined analysis showed maximum acute HQs of 4 for acrolein
and 2 for formaldehyde emissions based on the acute reference exposure
level. Maximum cancer risk due to ingestion exposures estimated using
health-protective risk screening assumptions are below 6-in-1 million
for the Tier 2 fisher scenario and below 40-in-1 million for the Tier 2
rural gardener exposure scenario.\2\ Considering all the health risk
information and factors and the uncertainties discussed in the preamble
to the proposed amendments (84 FR 47074, September 6, 2019), the EPA
proposed that the risks posed by emissions from the PCWP source
category are acceptable after implementation of the existing MACT
standards.
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    \2\ As explained in the preamble for the proposed rulemaking,
these multipathway risk estimates would be further reduced with Tier
3 screening.
---------------------------------------------------------------------------

    As directed by CAA section 112(f)(2), the EPA also conducted an
analysis to determine if the current emission standards provide an
ample margin of safety to protect public health. Under the ample margin
of safety analysis, the EPA considers all health factors evaluated in
the risk assessment and evaluates the cost and feasibility of available
control technologies and other measures (including the controls,
measures, and costs reviewed under the technology review) that could be
applied to this source category to further reduce the risks (or
potential risks) due to emissions of HAP identified in our risk
assessment. The EPA did not identify methods for further reducing HAP
emissions from the PCWP source category that would achieve meaningful
risk reductions. Therefore, the EPA proposed that the current PCWP
standards provide an ample margin of safety to protect public health
and revision of the promulgated standards is not required. The EPA also
concluded that an adverse environmental effect as a result of HAP
emissions from this source category is not expected and, therefore,
proposed 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. The results of the
EPA's residual risk analysis conducted according to CAA section
112(f)(2) were discussed in the preamble to the proposed rulemaking (84
FR 47074, September 6, 2019), in the risk report for the proposed
rulemaking titled Residual Risk Assessment for the Plywood and
Composite Wood Products Source Category in Support of the 2019 Risk

and Technology Review Proposed Rule, Docket Item No. EPA-HQ-OAR-2016-
0243-0179, and in the risk report for the final rule titled Residual
Risk Assessment for the Plywood and Composite Wood Products Source
Category in Support of the 2019 Risk and Technology Review Final Rule,
in the docket for this action. The risk report for the final rule is
unchanged from the risk report prepared for the proposed rulemaking.
2. How did the risk review change for the PCWP source category?
    The EPA has not changed any aspect of the risk assessment since the
September 2019 proposal for the PCWP source category.
3. What key comments did we receive on the risk review, and what are
our responses?
    The EPA received several comments in support of and against the
proposed residual risk review and our determination that no revisions
were warranted under CAA section 112(f)(2). Generally, the commenters
disagreeing with the risk review misunderstood the type of data used
for the development of the risk review or suggested changes to the
underlying risk assessment methodology. Some commenters noted the
conservative nature of the underlying residual risk methodology.
Commenters also submitted data revisions for 23 of the 233 modeled
facilities. After reviewing the inventory revisions, the EPA concluded
that 21 of the revisions would serve only to reduce modeled risk
through reduced emissions or improved dispersion inputs. Further, the
EPA concluded that neither of the two remaining inventory revisions
would increase the maximum modeled risk for the PCWP source category or
change our conclusions regarding risk acceptability or ample margin of
safety. See the memorandum, Review of Plywood and Composite Wood
Products Emissions Inventory Revisions, in the docket for this action
for details on the inventory revisions submitted. After review of the
comments and information submitted, we determined that no changes to
the proposed residual risk assessment were necessary. The comments and
our specific responses can be found in the RTC document, which is
available in the docket for this action, Docket ID No. EPA-HQ-OAR-2016-
0243.
4. What is the rationale for our final approach and final decisions for
the risk review?
    As noted in our proposal, 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''
(see 54 FR 38045, September 14, 1989). The EPA weighs all health risk
factors in our risk acceptability determination, including the cancer
maximum individual risk (MIR), cancer incidence, the maximum cancer
TOSHI, the maximum acute noncancer HQ, the extent of noncancer risks,
the distribution of cancer and noncancer risks in the exposed
population, and the risk estimation uncertainties.
    Since proposal, neither the risk assessment nor our determinations
regarding risk acceptability, ample margin of safety, or adverse
environmental effects have changed. For the reasons explained in the
proposed rulemaking, the EPA determined that the risks from the PCWP
source category are acceptable, the current standards provide an ample
margin of safety to protect public health, and more stringent standards
are not necessary to prevent an adverse environmental effect.
Therefore, the EPA is not revising the PCWP NESHAP (40 CFR part 63,
subpart DDDD) to require additional controls pursuant to CAA section
112(f)(2) based on the residual risk review, and the EPA is readopting
the existing standards under CAA section 112(f)(2).

B. Technology Review for the PCWP Source Category

    The EPA's technology review focused on identifying developments in
practices, processes, and control technologies for process units
subject to standards under the NESHAP that have occurred since 2004
when emission standards were promulgated for the PCWP source category.
The following process units were included in our review: Green rotary
dryers, hardboard ovens, pressurized refiners, primary tube dryers,
reconstituted wood product presses, softwood veneer dryer heated zones,
rotary strand dryers, secondary tube dryers, conveyor strand dryers,
fiberboard mat dryers, press predryers, and reconstituted wood product
board coolers. The technological basis for the promulgated PCWP NESHAP
was use of incineration-based or biofilter add-on controls to reduce
HAP emissions. Incineration-based controls include regenerative thermal
oxidizers (RTOs), regenerative catalytic oxidizers (RCOs), and
incineration of process exhaust in an onsite combustion unit (referred
to as ``process incineration''). In addition, the PCWP NESHAP contains
production-based compliance options (PBCO) for process units with low
emissions due to pollution prevention measures inherent in their
process, an emissions averaging compliance option, and work practice
requirements for selected process units. In the proposal, the EPA noted
a development in resin systems used to produce PCWP at some facilities
but found that facilities generally have not altered their HAP emission
control strategies to date as a result of resin changes and that it is
not necessary, or supported, based on available data, at this time, to
amend the current standards. The EPA proposed that no revisions to the
PCWP NESHAP are necessary pursuant to CAA section 112(d)(6).
    The EPA received comments supporting and opposing our proposed
determination from the technology review that no revisions to the
standards are necessary under CAA section 112(d)(6). Several commenters
agreed with the EPA's decision not to revise the current standards
pursuant to CAA section 112(d)(6). Conversely, another commenter
opposed our determination not to revise the standards and stated that
the EPA failed to satisfy the CAA because it did not set emission
standards for currently unrestricted HAP (such as emissions from the
PCWP process units not currently subject to emissions limits) and
regulating these emissions is ``necessary'' under the CAA. The
commenter asserted that the EPA must review and follow the CAA and
existing case law to ensure it sets a numerical limit for every
regulated HAP in order to satisfy CAA sections 112(d)(2), (3), and (6).
The commenter further asserted that the EPA must update standards when
a development is identified, such as the use of lower HAP resins.
    In response to the comments, the EPA maintains that our CAA section
112(d)(6) review of developments in the processes, practices, and
controls applied to sources regulated under 40 CFR part 63, subpart
DDDD, was complete. The technology review was based on responses to an
Information Collection Request (ICR) conducted under CAA section 114,
requiring a mandatory response. In addition to ICR data provided by
respondents, the EPA requested and reviewed other information from
sources to determine if there have been developments in practices,
processes, or control technologies by PCWP facilities, as described in
section 3 of the RTC document. The technology review was documented in
the memorandum, Technology Review for the Plywood and

Composite Wood Products NESHAP, Docket Item No. EPA-HQ-OAR-2016-0243-
0189.
    Section 3 of the RTC document contains full responses to the
comments received. Regarding the comment that the technology review did
not address the unregulated sources, the EPA acknowledged in the
preamble to the proposed rulemaking that there are unregulated sources
with no-control MACT determinations, and we stated our plans to address
those units in a separate action subsequent to the RTR at 84 FR 47077-
47078. See section 9 of the RTC document for further discussion of our
position regarding our obligations under CAA section 112(d)(6) with
respect to unregulated sources.\3\
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    \3\ On April 21, 2020, as the Agency was preparing the final
rule for signature, a decision was issued in LEAN v. EPA, 955 F. 3d.
1088 (D.C. Cir. 2020) in which the Court held that the EPA has an
obligation to set standards for unregulated pollutants as part of
technology reviews under CAA section 112(d)(6). At the time of
signature, the mandate in that case had not been issued and the EPA
is continuing to evaluate the decision.
---------------------------------------------------------------------------

    Overall, the EPA's review of the developments in technology for the
process units subject to the PCWP NESHAP did not reveal any changes
that require revisions to the emission standards under CAA section
112(d)(6). As discussed in the first paragraph in this section of the
preamble, the PCWP rule was promulgated with multiple options for
reducing HAP emissions to demonstrate compliance with the standard. The
EPA found that facilities are using each type of control system or
pollution prevention measure (such as lower-HAP resins) that was
anticipated when the PCWP emissions standards were promulgated. The EPA
did not identify any developments in practices, processes, or control
technologies for the regulated units beyond those accounted for in the
originally promulgated PCWP NESHAP.
    Regarding lower-HAP resins, for the proposal, the EPA characterized
changes in the type of resin systems used in the particleboard, MDF,
and hardwood plywood segments of the PCWP industry due to the
formaldehyde standards limiting emissions from these products \4\ as a
``development'' within the context of CAA section 112(d)(6). The EPA
explained in the proposal that as facilities conduct repeat testing,
they may find that the inlet concentration of formaldehyde and methanol
from their pressing operations has dropped if they are now using a
different, lower-HAP resin system to comply with the California Air
Resources Board (CARB) and Toxic Substances Control Act (TSCA)
standards. The decrease in inlet concentration may allow for future use
of the PBCO without an add-on control device, providing an existing
compliance option in addition to the current add-on control device
compliance option. The EPA also explained that while the CARB and TSCA
standards are a ``development'' within the context of CAA section
112(d)(6), these rules do not necessitate revision of the previously-
promulgated PCWP emission standards because the promulgated PCWP
emission standards already include the PBCO provisions for pollution
prevention measures such as lower-HAP resins. The EPA disagrees that
because resin changes made by some mills were noted as a development in
the technology review that this necessitates revisions to the standards
without regard to how the development is already addressed within the
previously-promulgated emission standards, to how it relates to control
technologies used in the industry, or other relevant factors. For the
PCWP source category, the EPA did not identify information suggesting
the resin system changes have significantly altered the type of process
units or HAP pollution control technologies used in the PCWP industry
to date or have led to processes or practices that have not been
accounted for in the promulgated PCWP NESHAP compliance options. As
explained further in Section 3 of the RTC document, at present, limited
HAP emissions data are available to compare PCWP manufacturing process
emissions before and after implementation of resin changes to meet the
product formaldehyde standards. Facilities made a variety of different
resin system changes (if needed for their specific products) in
response to the CARB and TSCA rules, and, therefore, no single broadly-
applicable approach feasible for all mills was identified. The
different resin system changes facilities made, coupled with the
limited available HAP emissions data, ongoing use of add-on control
technologies following resin system changes, and availability of PBCO
in the PCWP NESHAP do not support revising the PCWP NESHAP. Therefore,
the EPA concluded it is not, at this time, necessary or supportable
under this CAA section 112(d)(6) review to change the promulgated PCWP
NESHAP as a result of resin changes facilities made to meet the CARB
and TSCA rules. If additional emissions information on resin changes or
other changes made by facilities becomes available and indicates
updates need to be made to standards in future technology reviews, the
EPA will evaluate that information at that time. In summary, the EPA
proposed, and is finalizing the conclusion that no revisions to the
PCWP NESHAP are necessary pursuant to CAA section 112(d)(6). All
amendments being made to the final NESHAP are for reasons other than to
reflect developments under CAA section 112(d)(6).
---------------------------------------------------------------------------

    \4\ In 2008, the CARB finalized an Airborne Toxic Control
Measure (ATCM) to reduce formaldehyde emissions from hardwood
plywood, MDF, and particleboard. Consistent with the CARB ATCM, in
July 2010, Congress passed the Formaldehyde Standards for Composite
Wood Products Act, as title VI of TSCA, [15 U.S.C. 2697], requiring
the EPA to promulgate a national rule. The EPA finalized the TSCA
rule, Formaldehyde Emission Standards for Composite Wood Products,
on December 12, 2016 (81 FR 89674), and finalized an implementation
rule on February 7, 2018 (83 FR 5340). Compliance with the TSCA rule
was required by December 2018. The CARB ATCM and the rule to
implement TSCA title VI emphasize the use of low emission resins,
including ultra-low-emitting formaldehyde and no added formaldehyde
resin systems.
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C. SSM Provisions

    Consistent with the 2008 decision in Sierra Club v. EPA, the EPA
proposed eliminating the SSM exemption in this rule and instead
proposed that the same standards that apply during normal operation
also apply during SSM, except during specific periods of startup and
shutdown as described in section IV.C.2 of this preamble. Additionally,
the EPA proposed several revisions to Table 10 (the General Provisions
applicability table), proposed eliminating the incorporation of the
General Provisions' requirement that the source develop an SSM plan,
and proposed eliminating and revising certain recordkeeping and
reporting requirements related to the SSM exemption, all of which are
further described in section IV.C.4 of this preamble.
1. Elimination of the SSM Exemption
    As noted in section III.C of this preamble, in its 2008 decision in
Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), the Court 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
(h)(1), holding that under section 302(k) of the CAA, emissions
standards or limitations must be continuous in nature and that the SSM
exemption violates the CAA's requirement that some CAA section 112
standards apply continuously. Consistent with the Sierra Club decision,
the EPA proposed eliminating the SSM exemption in this rule from 40 CFR
63.2250 and to remove the incorporation of 40 CFR 63.6(f)(1). (40

CFR 63.6(h)(1) was not applicable to this NESHAP.)
    The EPA received comments supporting and opposing our proposal to
eliminate the SSM exemption in the rule. Commenters opposed to
eliminating the exemption stated that neither the CAA nor judicial
precedent requires the EPA to delete the SSM provisions. According to
these commenters, the best-performing facilities that are the basis for
the MACT floor experience SSM events, and so it is appropriate for the
EPA to recognize and account for those events, as it has in the
existing PCWP MACT standards. One commenter noted that when the EPA
promulgated the 2004 PCWP NESHAP, the EPA determined it was appropriate
not to subject mills to the numerical emission limitations in those
standards during SSM events, requiring instead that sources follow work
practices to minimize emissions during such events, including
developing and following an SSM plan. The commenter asserted that the
EPA's proposal to eliminate 40 CFR 63.2250(a), and thereby require
sources to meet the same emission limitations during periods of SSM,
except for very limited cases (safety related shutdowns and brief
periods during startup and shutdown of pressurized refiners),
represents an unauthorized change to existing MACT standards,
specifically claiming that it is not the product of the technology
review described in the CAA, it is not required by case law, and it is
inconsistent with decades of the EPA practice and judicial
interpretations of NESHAP and new source performance standards.
Conversely, a commenter in favor of the EPA's proposal to eliminate the
SSM exemption argued that it is legally required and necessary in this
rulemaking under CAA section 112(d), including CAA section 112(d)(6),
for the EPA to remove the SSM exemptions for PCWP facilities as it has
proposed to do because the CAA requires standards to apply continuously
and the Court precedent (Sierra Club v. EPA) is a development since the
prior standards were made.
    The EPA acknowledges comments in support of the removal of the 40
CFR part 63, subpart DDDD, SSM exemption and we are promulgating our
proposed SSM action. We disagree with comments suggesting that the
legal precedent established in case law (Sierra Club v. EPA, 551 F.3d
1019 (D.C. Cir. 2008) should not apply to subpart DDDD. The Court
decision held that emission limits under CAA section 112 must apply
continuously and meet minimum stringency requirements, even during
periods of SSM. Consistent with the Court's decision and for the
reasons explained in the proposal preamble at 84 FR 47092-47096, we are
finalizing our proposal to eliminate the SSM language in subpart DDDD.
As explained in the proposal, our SSM-related rule revisions are in
response to the Court's vacatur of the SSM exemptions in 40 CFR
63.6(f)(1) and (h)(1). When incorporated into CAA section 112(d)
regulations for specific source categories, these two provisions
exempted sources from the requirement to comply with otherwise
applicable MACT standards during periods of SSM. The Court's vacatur
rendered those provisions null and void prior to this rulemaking.
Eliminating reference to these provisions and other related General
Provisions referenced in subpart DDDD reflects the vacatur by the
Court. We also eliminated the rule specific SSM provisions in subpart
DDDD, as discussed further in section IV.C.4 of this preamble. The
specific changes in the language can be found in Docket ID No. EPA-HQ-
OAR-2016-0243 in the document titled Redline Version of 40 CFR Part 63,
subpart DDDD Showing Final Changes. However, we do not agree with the
commenter who characterized the 2008 Court ruling as a ``development''
that compels elimination of the SSM exemption under CAA section
112(d)(6). The EPA is not and need not rely on CAA section 112(d)(6) in
order to eliminate the exemption but is choosing to take action at this
time to make the NESHAP consistent with the 2009 ruling. As discussed
in section IV.C.2 below, we proposed and are promulgating work practice
standards for specific startup and shutdown events. Therefore, all
current subpart DDDD facilities affected by SSM must be in compliance
with a standard at all times (i.e., with either the normal operational
standards or the work practices that apply during selected startup and
shutdown periods) consistent with the Sierra Club v. EPA decision.
Section IV.C.3 of this preamble provides further information on our
position with respect to periods of malfunction.
2. Periods of Startup and Shutdown
    In finalizing the standards in this rule, the EPA considered and
proposed alternative actions to the simple removal of SSM provisions in
the rule. As an alternative approach consistent with Sierra Club v.
EPA, the EPA may designate different standards to apply during startup
and shutdown. The EPA collected information with the PCWP ICR to use in
determining whether applying the standards applicable under normal
operations would be problematic for PCWP facilities during startup and
shutdown. Facilities operating control systems generally operate the
control systems while the process unit(s) controlled are started up and
shut down. For example, RTOs and RCOs are warmed to their operating
temperature set points using auxiliary fuel before the process unit(s)
controlled startup, and the oxidizers continue to maintain their
temperature until the process unit(s) controlled shutdown. Biofilters
operate within a biofilter bed temperature range that will be more
easily achieved during startup and shutdown with changes in biofilter
bed temperature operating range discussed in section IV.F of this
preamble. Based on the information collected, the EPA determined that
PCWP facilities can meet standards applicable under normal operations
at all times except during periods of safety-related shutdowns and
pressurized refiner startups and shutdowns. To ensure that a CAA
section 112 standard is met during all times, the EPA proposed
alternate work practice standards for safety-related shutdowns and
pressurized refiner startups and shutdowns. After considering comments
on the proposed amendments, the EPA determined that an alternate work
practice standard was also needed for direct-fired softwood veneer
dryers undergoing startup or shutdown of gas-fired burners.
    The following sections discuss the work practices the EPA is
finalizing. Each work practice is designed to minimize emissions, in
keeping with CAA requirements. All three work practices minimize the
duration of time and circumstances under which they can be applied.
Further, because all three work practices require the temporary
suspension of material flow through the PCWP process, PCWP facilities
are incentivized to minimize the use and duration of these work
practices. Sections IV.C.2.a and b of this preamble discuss in more
detail the work practice standards for safety-related shutdowns and
pressurized refiner startup and shutdown, respectively, including
comments received about the standards following proposal and the EPA's
final decision regarding their requirements. Section IV.C.2.c of this
preamble discusses the details of the work practice standard for
direct-fired softwood veneer dryers undergoing startup or shutdown of
gas-fired burners.
a. Safety-Related Shutdowns
    As discussed in the preamble to the proposed rulemaking (84 FR
47093,

September 6, 2019) and further elaborated in the RTC document, safety-
related shutdowns differ from routine, planned shutdowns where
facilities can continue routing process unit emissions to the control
device until the process unit is shut down. Safety-related shutdowns
have been accounted for in the process design and are not necessarily
frequent but are pre-determined remedial actions anticipated to
occasionally occur to such a degree that they are also distinguished
from malfunctions which are, by definition, infrequent and not
reasonably preventable (40 CFR 63.2). Malfunctions are unpredictable
and may require different types of remediation. For example, the PCWP
process predictably shuts down when these events are triggered. Safety-
related shutdowns must occur rapidly in the event of unsafe conditions
such as a suspected fire in a process unit heating flammable wood
material. When unsafe conditions are detected, facilities must act
quickly to shut off fuel flow (or indirect process heat) to the system,
cease addition of raw materials (e.g., wood furnish, resin) to the
process units, purge wood material and gases from the process unit, and
isolate equipment to prevent loss of property or life and protect
workers from injury. Because it is unsafe to continue to route process
gases to the control system, the control system will be bypassed as the
process quickly shuts down, in many cases automatically, through a
system of interlocks designed to prevent dangerous conditions from
occurring.
    In order to clarify what constitutes a safety-related shutdown, the
EPA proposed a new definition in 40 CFR 63.2292 defining a safety-
related shutdown as an unscheduled shutdown of a process unit subject
to a compliance option in Table 1B to 40 CFR part 63, subpart DDDD, (or
a process unit with HAP control under an emissions averaging plan
developed according to 40 CFR 63.2240(c)) during which time emissions
from the process unit cannot be safely routed to the control system in
place to meet the compliance options or operating requirements in
subpart DDDD without imminent danger to the process, control system, or
system operator. The EPA also proposed a work practice standard for
safety-related shutdowns requiring facilities to follow documented
site-specific procedures such as use of automated controls or other
measures developed to protect workers and equipment to ensure that the
flow of raw materials (such as furnish or resin) and fuel or process
heat (as applicable) ceases and that material is removed from the
process unit(s) as expeditiously as possible given the system design.
These actions are taken by all (including the best-performing)
facilities when safety-related shutdowns occur.
    Comments were received both supporting and opposing the proposed
work practice for safety-related shutdowns. Commenters in support of
the standards stated that CAA section 112(h) allows the EPA to
promulgate a design, equipment, work practice, or operational standard,
or combination thereof, in two circumstances: (1) When HAP ``cannot be
emitted through a conveyance designed and constructed to emit or
capture such a pollutant, or that any requirement for, or use of, such
a conveyance would be inconsistent with any Federal, State, or local
law,'' and (2) when ``the application of measurement methodology . . .
is not practicable due to technological and economic limitations.''
Commenters stated that safety-related shutdowns of process units with
add-on control equipment present both of those circumstances and
provided operational details summarized in Section 4.3 of the RTC
document. The commenter explained that the best practice for
controlling HAP emissions during such safety-related shutdowns is to
minimize the duration of the event by promptly ceasing the addition of
raw materials and heat to the process and removing materials from
process equipment as soon as possible (although in some instances it is
safer to have the material remain in the process equipment to contain a
problem such as a fire).
    A separate commenter opposed the EPA's proposed safety-related
shutdown work practice standards, arguing that the EPA has not
explained how the criteria under CAA section 112(h) are met to provide
the EPA the statutory authority to set work practices. The commenter
stated that the work practice standards the EPA proposed are too lax
because they are written by the facilities with no requirement for
approval by the EPA. The commenter contended that the work practices
will not achieve ``maximum'' emission reduction because they only
instruct facilities to protect workers and process equipment, with no
reference to reducing air emissions. The commenter urged the EPA to
clarify how recordkeeping requirements would apply in the context of
work practice standards. The full comments and our responses pertaining
to safety-related shutdowns are included in the RTC document. According
to CAA section 112(h)(1), MACT standards may take the form of design,
equipment, work practice, or operational standards ``if it is not
feasible in the judgement of the Administrator to prescribe or enforce
an emission standard.'' The phrase ``if it is not feasible to prescribe
or enforce an emission standard'' is defined in CAA section
112(h)(2)(A) and (B) to mean any situation in which the Administrator
determines that: (A) A HAP or pollutants cannot be emitted through a
conveyance designed and constructed to emit or capture such pollutant,
or that any requirement for, or use of, such a conveyance would be
inconsistent with any federal, state or local law, or (B) the
application of measurement methodology to a particular class of sources
is not practicable due to technological and economic limitations.
    The EPA has determined that work practices are appropriate during
safety-related shutdowns in the PCWP industry because facilities cannot
capture and convey HAP emissions to a control device during these
periods for safety reasons. The control device could serve as an
ignition source if there is an upset in the oxygen concentration or
buildup of other combustibles in the PCWP process or exhaust gas
collection system (e.g., combustible gas, condensed pitch on ductwork
if moisture-laden gases in the system are allowed to cool, or wood
dust) due to various conditions (e.g., if PCWP process equipment or
pneumatic conveying systems become plugged). If there are sparks or
fire in the PCWP process unit, conveyance, or the control device, the
equipment could be damaged if exhaust continues to be routed from the
PCWP process unit to the control device. A PCWP dryer or control device
may experience an over-temperature condition indicative of a fire and
triggering rapid equipment isolation. Thus, conveying emissions from
the PCWP process unit to the control device is not technically feasible
during safety-related shutdowns.
    Further, application of measurement methodology is not practicable
due to technological and economic limitations. Safety-related shutdowns
are brief events that are incorporated into the process design for
safety reasons but are not desirable operating conditions that
constitute normal operations. Even if staged especially for an
emissions measurement (which is economically impracticable due to lost
production), the duration of safety-related shutdowns is necessarily
brief (i.e., minutes), less than the 1 hour it takes to collect a
single emissions measurement sample if the equipment is set up and
measurement contractors are onsite ready to sample, let alone the 3
hours needed for a full emissions test. Because

a full emissions measurement sample cannot be obtained during a safety-
related shutdown, application of measurement methodology is not
practicable due to technological limitations in addition to being
economically impracticable. Therefore, it is the EPA's determination
that PCWP-industry safety-related shutdowns meet the criteria in CAA
section 112(h)(2)(B).
    Based on our authority to set work practices, the EPA is finalizing
a definition of ``safety-related shutdown'' in 40 CFR 63.2292 and
finalizing a work practice for these shutdown events. The work practice
is designed to be consistent with actions commonly undertaken by
facilities to protect plant personnel, production equipment, and
control equipment from dangerous circumstances like fires and
explosions. The final work practice requires facilities to follow
documented site-specific procedures such as use of automated controls
or other measures developed to protect workers and equipment to ensure
that the flow of raw materials (such as furnish or resin) and fuel or
process heat (as applicable) ceases and that material is removed from
the process unit(s) as expeditiously as possible given the system
design to reduce air emissions. The phrase ``to reduce air emissions''
was added to the standard to address the concern expressed by one
commenter that the work practice should direct facilities to consider
air quality. The actions required by the safety-related shutdown work
practice represent the maximum degree of emissions reduction achievable
because they limit the amount of time, as well as the flow of raw
materials and fuel into the process, and, therefore, emissions from the
process undergoing safety-related shutdown. Rule language relating to
the safety-related shutdown work practice was strengthened for the
final rule in response to the commenter's concern that the EPA is
giving full discretion to the facilities to develop their safety-
related shutdown work practices for their own equipment configurations
without oversight by the EPA. To strengthen the standard, the EPA added
an initial compliance requirement to Table 6 of the final rule to
clarify that facilities must have a record of safety-related shutdown
procedures available for inspection by the delegated authority upon
request. In addition, a recordkeeping requirement was added to Table 8
of the final rule to ensure documentation is available to track when
the work practice is used, consistent with the proposed requirement
under 40 CFR 63.2282(a)(2)(i). Finally, a reporting requirement was
added to 40 CFR 63.2281(c)(4) to require facilities to report the
number of instances and total amount of time during the reporting
period when the safety-related shutdown work practice is used. If the
safety-related shutdown work practice is used for more than 100 hours
during a reporting period, the facility must report the date, time, and
duration of each instance when the work practice was used. The EPA has
concluded that these initial compliance and ongoing recordkeeping and
reporting measures are sufficient to provide delegated authorities with
information needed for oversight.
    In addition, to clarify requirements, 40 CFR 63.2250(f)(6) was
added to the final rule to state that the otherwise applicable
compliance options, operating requirements, and work practice
requirements (in rows 1 through 5 of Table 3 to 40 CFR part 63, subpart
DDDD) do not apply when the startup/shutdown work practices apply
(i.e., the work practices in rows 6 through 8 of Table 3 to subpart
DDDD for safety-related shutdown, pressurized refiner startup and
shutdown, and softwood veneer dryer gas-burner relights). Thus,
compliance with the startup/shutdown work practices (in Table 3 to
subpart DDDD, rows 6 through 8) does not constitute a failure to meet
the otherwise applicable compliance options, operating requirements,
and work practice requirements because these requirements do not apply
while the startup/shutdown work practices apply. Finally, 40 CFR
63.2271(b)(4) was added to clarify that instances when the startup/
shutdown work practice requirements are used (as reported under 40 CFR
63.2281(c)(4)) are not considered to be deviations from (or violations
of) the otherwise applicable compliance options, operating
requirements, and work practice requirements (in rows 1 through 5 of
Table 3 to subpart DDDD) as long as facilities do not exceed the
minimum amount of time necessary for these events.
b. Pressurized Refiner Startups and Shutdowns
    Pressurized refiners use steam to heat and soften wood under
pressure to grind it apart between rotating discs into fibers.
Pressurized refiners discharge wood fiber and exhaust gases from
refining directly into a primary tube dryer. Pressurized refiners
cannot be vented through the dryer to the control system (i.e., the
dryer control system) for a brief time after they are initially fed
wood material during startup and as wood material clears the refiner
during shutdown because they are not producing useable fiber suitable
for drying or producing PCWP products (hardboard or MDF). During this
time, instead of the pressurized refiner output being discharged into
the dryer, exhaust is vented to the atmosphere (e.g., through an abort
cyclone) and the wood is directed to a reclaim bin for storage and,
commonly, recycling back into the refining process once it is running
steadily. No resin is mixed with the off-specification material and the
time periods are short (e.g., 15 minutes or less) before the
pressurized refiner begins to discharge wood fiber and exhaust through
the dryer and when the refiner is shutting down.
    The EPA proposed a work practice requirement in Table 3 of the rule
(40 CFR part 63, subpart DDDD) to apply during pressurized refiner
startup and shutdown that limits the amount of time (and, thus,
emissions) when wood is being processed through the system while
exhaust is not routed through the dryer to its control system. This
practice is consistent with how the best-performing facilities complete
startup and shutdown of pressurized refiners. The proposed work
practice stated that facilities must route exhaust gases from the
pressurized refiner to its control system no later than 15 minutes
after furnish is fed from the pressurized refiner to the tube dryer
when starting up, and no more than 15 minutes after furnish ceases to
be fed to the pressurized refiner when shutting down.
    Comments were received both supporting and opposing the pressurized
refiner startup and shutdown work practice standard. Commenters
supporting the work practice stated that periods of startup and
shutdown of pressurized refiners meet the CAA section 112(h) criteria
for establishing a work practice standard, while commenters opposing
the work practice argued that the EPA does not have statutory authority
to apply work practice standards instead of numerical emissions limits
to pressurized refiner startup and shutdown periods.
    Commenters in support of the EPA's proposed work practice standard
for startup and shutdown of pressurized refiners noted that the
language of the standard in Table 3 to 40 CFR part 63, subpart DDDD
appears to have a typographical error. The commenters suggested
rewording the standard in Table 3 so that it instructs facilities to
route exhaust gases from the pressurized refiner to the dryer control
system no

later than 15 minutes after wood is fed to the pressurized refiner when
starting up and to stop wood flow to the pressurized refiner no more
than 15 minutes after wood fiber stops being fed to the dryer from the
pressurized refiner. The commenter opposing the work practice standard
also questioned the timing and recordkeeping requirements. The full
comments and our responses pertaining to pressurized refiners are
included in the RTC document.
    In response to these comments, the EPA concluded pressurized
refiner startup and shutdown events meet the criteria in CAA section
112(h)(2)(B). Pressurized refiners are a particular class of sources
where emissions are associated with wood processed through the refiner.
Pressurized refiners cannot discharge unusable fiber through the tube
dryer and its control system during startup and shutdown. Because
venting through the pressurized refiner abort cyclone during startup
and shutdown of pressurized refiners typically lasts 15 minutes or
less, there are technological limitations to measuring emissions
because HAP measurement methods require a 1-hour sampling time per test
run, and a total of three test runs. The only way to obtain the
required sample would be to operate in abort mode for each 1-hour
sampling time. However, abort ``bins'' used to collect the off-spec
wood furnish dumped from the system are not designed like material
collection bins or silos for useable furnish at wood products
facilities. Instead, the abort ``bins'' are often areas where off-spec
fiber is dumped on the ground between concrete wind-breaks where it is
removed with a front-end loader. Such areas do not have the capacity
for dumping large amounts of fiber as would be needed to stage an event
for 1 to 3 hours of testing, presenting another technological
limitation. Staging abort dumping of 1 to 3 hours of fiber production
also presents obvious economic limitations due to lost production for
that time and loss or degradation of valuable fiber raw material.
Finally, measuring emissions during pressurized refiner startup and
shutdown is impractical because the PCWP NESHAP requires emissions
measurement under representative operating conditions that are the
conditions under which the process unit typically operates, excluding
periods of startup and shutdown. Therefore, the EPA is finalizing a
work practice for pressurized refiner startup and shutdown periods.
    The EPA agrees that the wording of the proposed work practice
standard for pressurized refiners in Table 3 needed clarification and
has rewritten the standard for the final rule to instruct facilities to
route exhaust gases from the pressurized refiner to its dryer control
system no later than 15 minutes after wood is fed to the pressurized
refiner during startup, and to stop wood flow into the pressurized
refiner no more than 15 minutes after wood fiber and exhaust gases from
the pressurized refiner stop being routed to the dryer during shutdown.
In addition, we strengthened the work practice for startup/shutdown of
pressurized refiners in the final rule by clarifying when the startup/
shutdown work practice applies in 40 CFR 63.2250(f)(6), adding an
initial compliance requirement to Table 6 of 40 CFR part 63, subpart
DDDD, and adding a recordkeeping requirement to Table 8 of subpart DDDD
to track when the work practice is used, consistent with the proposed
requirement under 40 CFR 63.2282(a)(2)(i). Continuous compliance and
reporting provisions were also added in 40 CFR 63.2271(b)(4) and
63.2281(c)(4), respectively, to provide clarity and aid in
enforceability of the work practice requirement.
c. Veneer Dryer Burner Relights
    An issue with veneer dryer burner relights stemming from removal of
the SSM exemption was raised during the comment period for the proposed
amendments. The EPA received a comment seeking clarification for
direct-fired softwood veneer dryers undergoing relights of gas-fired
burners. Specifically, the commenter noted that 40 CFR 63.2250(d) of
the current PCWP rule defines shutoff of direct-fired burners resulting
from partial or full production stoppages as shutdowns and the lighting
or re-lighting of any one or all gas burners in direct-fired softwood
veneer dryers as startups and not a malfunction. The commenter noted
that the EPA proposed no changes to 40 CFR 63.2250(d) which was
originally included in the PCWP rule to clarify that veneer dryer
burner relights are not malfunctions due to their frequency. In the
2004 promulgated standard, these startup/shutdown events were required
to be addressed under the SSM plan. The commenter explained that
following the flame out of the burner, the dryer could contain non-
combusted natural gas that must be purged prior to safely re-lighting
the gas burners. Non-combusted natural gas cannot be exhausted to the
control device due to safety concerns and must be vented along with
whatever process emissions are in the dryer. The length of the purge
varies based on system design, but only lasts a matter of minutes.
Emissions are routed to the control system as expeditiously as possible
following the burner re-light. Therefore, the commenter stated a dryer
gas burner re-lighting startup work practice is needed for the same
reasons as a safety shutdown work practice. However, because 40 CFR
63.2250(d) deals with dryer re-lights by defining them as startups, and
the proposed rulemaking no longer contains a general exemption for
startups, the commenter stated that some provision is needed for veneer
dryer gas burner lighting and re-lighting.
    In response to this comment, the EPA added a work practice to Table
3 of the final rule to clarify the requirements surrounding softwood
veneer dryer gas-fired burner relights to ensure a standard applies
continuously once the SSM plan is no longer required. The work practice
requires direct-fired softwood veneer dryers undergoing startup or
shutdown of gas-fired burners to cease feeding green veneer into the
softwood veneer dryer and minimize the amount of time direct gas-fired
softwood veneer dryers are vented to the atmosphere due to the
conditions described in 40 CFR 63.2250(d). Related text was added to 40
CFR 63.2250(f) noting the work practice in Table 3 of 40 CFR part 63,
subpart DDDD, applies when the otherwise applicable compliance options
and operating requirements in the rule cannot be met. An initial
compliance requirement was added to Table 6 of subpart DDDD to have a
record of the procedures for startup and shutdown of softwood veneer
dryer gas-fired burners available for inspection upon request by the
delegated authority. In addition, a recordkeeping requirement was added
to Table 8 of subpart DDDD to track when the work practice is used,
consistent with the proposed requirement under 40 CFR 63.2282(a)(2)(i).
Continuous compliance and reporting provisions were also added in 40
CFR 63.2271(b)(4) and 63.2281(c)(4), respectively, to provide clarity
and aid in enforceability of the work practice requirement. Conforming
changes to refer to the veneer dryer burner relight work practice with
the other startup/shutdown work practices were also made throughout the
rule.
    Further clarification with respect to 40 CFR 63.2250(d) is needed
as a result of our proposal to remove the SSM exemption (including the
SSM plan). The EPA determined that a work practice is appropriate
during direct-fired softwood veneer dryer startups/shutdowns of gas-
fired burners because the conditions of CAA section 112(h)(2)(A) and
(B) are both present during veneer dryer burner relights.

Facilities cannot capture and convey HAP emissions to a control device
during these periods for safety reasons. The control device for the
veneer dryer could serve as an ignition source if there is an upset in
the oxygen concentration or increase in the natural gas concentration
in the system. Thus, is it not technically feasible for HAP emissions
to be conveyed to the control device during startups/shutdowns
associated with softwood veneer dryer gas-burner relights. Further,
application of measurement methodology is not practicable due to
technological and economic limitations. Softwood veneer dryer burner
relights are brief events that take less than the 1 hour it takes to
collect a single emissions measurement sample if the equipment is set
up and measurement contractors are onsite ready to sample, let alone
the 3 hours needed for a full emissions test. Because a full emissions
measurement sample cannot be obtained while softwood veneer dryers are
undergoing gas-burner relights, application of measurement methodology
is not practicable due to technological limitations. In addition,
attempting to stage softwood veneer dryer burner relights for purposes
of emissions measurement is economically impracticable because veneer
is not being dried or moving through the veneer dryer when the burners
are not lit, resulting in a production loss during testing. Therefore,
the EPA concludes that direct-fired softwood veneer dryers undergoing
startup/shutdown of gas-fired burners meet the criteria in CAA section
112(h)(2)(B).
3. Periods of Malfunction
    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 (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 and this reading
has been upheld as reasonable by the Court in U.S. Sugar Corp. v. EPA,
830 F.3d 579, 606-610 (2016). 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
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. The EPA is not required to treat
a malfunction 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.
    As the Court recognized in U.S. Sugar Corp, accounting for
malfunctions in setting 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. Id. at 608 (``the
EPA would have to conceive of a standard that could apply equally to
the wide range of possible boiler malfunctions, ranging from an
explosion to minor mechanical defects. Any possible standard is likely
to be hopelessly generic to govern such a wide array of
circumstances''). 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 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.
    Although no statutory language compels the EPA to set standards for
malfunctions, the EPA has the discretion to do so where feasible. For
example, in the Petroleum Refinery Sector RTR, the EPA established a
work practice standard for unique types of malfunction that result in
releases from pressure relief devices or emergency flaring events
because the EPA had information for that source category to determine
that such work practices reflected the level of control that applies to
the best performers. 80 FR 75178, 75211-14 (December 1, 2015). In the
proposed rulemaking for the PCWP, the EPA did not propose a work
practice standard for malfunctions but instead stated that the EPA
would consider whether circumstances warrant setting standards for a
particular type of malfunction and, if so, whether the EPA has
sufficient information to identify the relevant best performing sources
and establish a standard for such malfunctions. The EPA encouraged
commenters to provide any such information.
    Numerous comments were received supporting and opposing the EPA's
decision not to set a standard for malfunctions. One commenter opposed
to the EPA's decision stated that there are several options the EPA
could use

for setting emission standards under CAA section 112 that would apply
during malfunction events. For example, the commenter stated that the
EPA might be able to establish a numerical emission limitation that
applies at all times but has an averaging time of sufficient duration
that short, infrequent spikes in emissions due to malfunctions would
not cause the source to exceed the emission limitation (while at the
same time ensuring that the source does not operate in a way that
causes frequent, lengthy excursions above the normal controlled
emission rate). The EPA also could use the flexibility accorded by CAA
section 302(k) (which defines ``emission limitation'' and ``emission
standard'' to include ``any requirement relating to the operation or
maintenance of a source to ensure continuous emission reduction, and
any design, equipment, work practice or operational standard
promulgated under'' the CAA) to address emissions during malfunction
events through operational requirements rather than by applying the
same limits on pollutant emissions that apply during normal operations.
Similarly, the commenter stated the EPA has grounds to exercise its
authority under CAA section 112(h) to promulgate a design, equipment,
work practice, or operational standard, or combination thereof, because
it is not feasible to prescribe or enforce an emission standard. The
commenter noted that even if the EPA does not identify a set of
specific work practices that all affected facilities can follow that
represent best practices for minimizing emissions during malfunctions,
the EPA might instead be able to address malfunctions through a set of
criteria that allows facilities to develop and follow a site-specific
plan for minimizing the extent and duration of excess emissions during
malfunctions. The commenter suggested that the EPA might use several of
these approaches in combination and stated that accommodating
malfunctions need not result in either an exemption or an increased
numerical emission limitation. The commenter urged the EPA to use its
authority under CAA sections 112 and 302(k) to address malfunctions in
a reasonable, CAA section 112-compliant manner.
    Conversely, another commenter supported the EPA's proposed removal
of unlawful SSM exemptions in all forms because the CAA requires
standards to apply continuously, and the Court precedent is a
development since the prior standards were issued.
    After considering all comments, the EPA is not finalizing a
separate standard for periods of malfunction. In the PCWP proposed
rulemaking, we requested comment and information to support the
development of a work practice standard during periods of malfunction,
but we did not receive sufficient information, including additional
quantitative emissions data, on which to base a standard for periods of
malfunction. Absent sufficient information, it is not reasonable at
this time to establish a work practice standard for malfunctions for
this source category.
4. Revisions to Table 10 to Subpart DDDD of Part 63
    The EPA proposed several specific revisions to Table 10 to subpart
DDDD of part 63 (the General Provisions table) to establish standards
in this rule that apply at all times. The EPA is finalizing the
amendments as proposed, with the clarifications noted in the following
sections. The specific revisions are described in the remainder of this
section.
a. General Duty (40 CFR 63.2250)
    The EPA is finalizing the General Provisions table (Table 10) entry
for 40 CFR 63.6(e)(1) and (2) by redesignating it as 40 CFR
63.6(e)(1)(i) and changing the ``yes'' in column 4 to a ``no'' in
column 5 which was added to specify requirements 1 year after the
effective date of the final amendments. 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. The EPA is instead adding a general
duty regulatory text at 40 CFR 63.2250 that reflects the general duty
to minimize emissions while eliminating the reference to periods
covered by an SSM exemption. The current language in 40 CFR
63.6(e)(1)(i) characterizes what the general duty entails during
periods of SSM. With the elimination of the SSM exemption, there is no
need to differentiate between normal operations, startup and shutdown,
and malfunction events in describing the general duty. Therefore, the
language the EPA is finalizing for 40 CFR 63.2250 does not include that
language from 40 CFR 63.6(e)(1).
    The EPA is also revising the General Provisions table (Table 10) by
adding an entry for 40 CFR 63.6(e)(1)(ii) and including a ``no'' in
column 5. 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 63.2250.
b. SSM Plan
    The EPA is finalizing revisions to the General Provisions table
(Table 10) to add an entry for 40 CFR 63.6(e)(3) by changing the
``yes'' in column 4 to a ``no'' in column 5. Generally, the paragraphs
under 40 CFR 63.6(e)(3) require development of an SSM plan and specify
SSM recordkeeping and reporting requirements related to the SSM plan.
As noted, the EPA is finalizing removal of 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
    The EPA is finalizing revisions to the General Provisions table
(Table 10) entry for 40 CFR 63.6(f)(1) by changing the ``yes'' in
column 4 to a ``no'' in columns 4 and 5. The final revision in column 4
refers to 40 CFR 63.2250(a). The current language of 40 CFR 63.6(f)(1)
exempts sources from non-opacity standards during periods of SSM. As
discussed in section IV.C.1 of this preamble, the Court in Sierra Club
v. EPA vacated the exemptions contained in this provision and held that
the CAA requires that some CAA section 112 standards apply
continuously. Consistent with the Court decision, the EPA is finalizing
the revised standards in this rule to apply at all times.
    The EPA is finalizing revisions to the General Provisions table
(Table 10) entry for 40 CFR 63.6(h)(1) through (9) by redesignating it
as 40 CFR 63.6(h)(1) and changing the ``NA'' in column 4 to a ``no'' in
column 5. The current language of 40 CFR 63.6(h)(1) exempts sources
from opacity standards during periods of SSM. As discussed in section
IV.C.1 of this preamble, 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 continuously. Consistent with
the Court decision, the EPA is finalizing the revised standards in this
rule to apply at all times.
d. Performance Testing (40 CFR 63.2262)
    The EPA is finalizing revisions to the General Provisions table
(Table 10) entry for 40 CFR 63.7(e)(1) by changing the ``yes'' in
column 4 to a ``no'' in column 5. Section 63.7(e)(1) describes
performance testing requirements. The

EPA is finalizing instead the addition of a performance testing
requirement at 40 CFR 63.2262(a) and (b). The performance testing
requirements the EPA is adding differ from the General Provisions
performance testing provisions in several respects. The regulatory text
does not include the language in 40 CFR 63.7(e)(1) that restated the
SSM exemption. The finalized performance testing provisions remove
reference to 40 CFR 63.7(e)(1), reiterate the requirement that was
already included in the PCWP rule to conduct emissions tests under
representative operating conditions, and clarify that representative
operating conditions excludes periods of startup and shutdown. As in 40
CFR 63.7(e)(1), performance tests conducted under this subpart should
not be conducted during malfunctions because conditions during
malfunctions are not representative of normal operating conditions. The
EPA is finalizing added language that requires the owner or operator to
record the process information that is necessary to document operating
conditions during the test and include in such record an explanation to
support that such conditions are representative. Section 63.7(e)
requires that the owner or operator make available to the Administrator
such records ``as may be necessary to determine the condition of the
performance test'' upon request but does not specifically require the
information to be recorded. The added regulatory text to this provision
that the EPA is finalizing builds on that requirement and makes
explicit the requirement to record the information.
    The EPA is also finalizing the definition of ``representative
operating conditions'' in 40 CFR 63.2292 to clarify that it excludes
periods of startup and shutdown. Representative operating conditions
include a range of operating conditions under which the process unit
and control device typically operate and are not limited to conditions
of optimal performance of the process unit and control device.
e. Monitoring
    The EPA is finalizing revisions to the General Provisions table
(Table 10) entry for 40 CFR 63.8(c)(1)(i) and (iii) by changing the
``yes'' in column 4 to a ``no'' in column 5. 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)).
    The EPA is finalizing revisions to the General Provisions table
(Table 10) by adding an entry for 40 CFR 63.8(d)(3) and including a
``no'' in column 5. 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 finalizing adding to the rule at 40 CFR
63.2282(f) text 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 40
CFR 63.8(d)(2).''
f. Recordkeeping (40 CFR 63.2282)
    The EPA is finalizing revisions to the General Provisions table
(Table 10) entry for 40 CFR 63.10(b)(2)(i) through (iv) by
redesignating it as 40 CFR 63.10(b)(2)(i) and changing the ``yes'' in
column 4 to a ``no'' in column 5. Section 63.10(b)(2)(i) describes the
recordkeeping requirements during startup and shutdown. The EPA is
finalizing instead the addition of recordkeeping requirements to 40 CFR
63.2282(a). When a source is subject to a different standard during
startup and shutdown, it will be important to know when such startup
and shutdown periods begin and end to determine compliance with the
appropriate standard. Thus, the EPA is finalizing adding language to 40
CFR 63.2282(a) requiring that sources subject to an emission standard
during startup or shutdown that differs from the emission standard that
applies at all other times must record the date, time, and duration of
such periods.
    The EPA is finalizing revisions to the General Provisions table
(Table 10) by adding an entry for 40 CFR 63.10(b)(2)(ii) and including
a ``no'' in column 5. Section 63.10(b)(2)(ii) describes the
recordkeeping requirements during a malfunction. The EPA is finalizing
the addition of such requirements to 40 CFR 63.2282(a). The final
regulatory text the EPA is adding 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 finalizing this requirement to apply to any
failure to meet an applicable standard and is requiring that the source
record the date, time, and duration of the failure rather than the
``occurrence.'' The EPA is also finalizing adding to 40 CFR 63.2282(a)
a requirement that sources keep records that include a list of the
affected source or equipment and actions taken to minimize emissions,
an estimate of the quantity of each regulated pollutant emitted over
the compliance option in 40 CFR 63.2240 the source failed to meet
(including the compliance options in Table 1A or B to 40 CFR part 63,
subpart DDDD, or the emissions averaging compliance option), 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 finalizing the
requirement 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. For each
failure to meet an operating requirement in Table 2 to subpart DDDD or
work practice requirement in Table 3 to subpart DDDD, facilities must
maintain sufficient information to estimate the quantity of each
regulated pollutant emitted over the emission limit. This information
must be sufficient to provide a reliable emissions estimate if
requested by the Administrator.
    The EPA is finalizing revisions to the General Provisions table
(Table 10) by adding an entry for 40 CFR 63.10(b)(2)(iv) and including
a ``no'' in column 5. When applicable, the provision requires sources
to record actions taken during SSM events when actions were
inconsistent with their SSM plan. The requirement is no longer
appropriate because SSM plans will no longer be required. The
requirement previously applicable under 40 CFR 63.10(b)(2)(iv)(B) to
record actions to minimize emissions and record corrective actions is
now applicable by reference to 40 CFR 63.2282(a).
    The EPA is finalizing revisions to the General Provisions table
(Table 10) by adding 40 CFR 63.10(b)(2)(v) to the entry for 40 CFR
63.10(b)(2)(iv) and including a ``no'' in column 5. 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.
    The EPA is finalizing revisions to the General Provisions table
(Table 10) by adding an entry for 40 CFR 63.10(c)(15) and including a
``no'' in column 5. The EPA is finalizing 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 SSM plan or records kept
to satisfy the recordkeeping requirements of the SSM 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 finalizing eliminating this 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. Reporting (40 CFR 63.2281)
    The EPA is finalizing revisions to the General Provisions table
(Table 10) entry for 40 CFR 63.10(d)(5) by redesignating it as 40 CFR
63.10(d)(5)(i) and changing the ``yes'' in column 4 to a ``no'' in
column 5. Section 63.10(d)(5)(i) describes the reporting requirements
for SSM events. To replace the General Provisions reporting
requirement, the EPA is finalizing adding reporting requirements to 40
CFR 63.2281(d) and (e). The replacement language differs from the
General Provisions requirement in that it eliminates periodic SSM
reports as a stand-alone report. The EPA is finalizing language that
requires sources that fail to meet an applicable compliance option in
40 CFR 63.2240 at any time to report the information concerning such
events in the semiannual compliance report already required under this
rule. The EPA is finalizing that the report must contain the number,
date, time, duration, and the cause of such events (including unknown
cause, if applicable), a list of the affected source or equipment, an
estimate of the quantity of each regulated pollutant emitted over any
emission limit, and a description of the method used to estimate the
emissions. Examples of such methods would include product-loss
calculations, mass balance calculations, measurements when available,
or engineering judgment based on known process parameters. The EPA is
finalizing 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.
    A commenter on the proposed rulemaking stated that facilities may
not have information to estimate emissions resulting from a deviation
from an operating parameter limit (e.g., low oxidizer or biofilter
temperature), and requested that emissions estimates only be required
to be recorded or reported for failure to meet an emission limit. As
explained in the RTC document included in the docket, EPA agrees that
precise measurement of PCWP process unit emissions during an operating
requirement deviation under the PCWP NESHAP is challenging unless the
failure occurs during a performance test. Therefore, 40 CFR
63.2281(e)(12) was updated for the final rule to require reporting of
an emission estimate only for failures to meet the numerical emission
compliance options in 40 CFR 63.2240, including the compliance options
in Table 1A or 1B of subpart DDDD or the emissions averaging compliance
option. As noted in section IV.C.4.f of this preamble, 40 CFR
63.2282(a) requires recordkeeping of sufficient information to provide
an emissions estimate associated with failure to meet an operating or
work practice requirement, if requested by the Administrator.
    The EPA 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 finalized
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.
    The EPA is finalizing revisions to the General Provisions table
(Table 10) by adding an entry for 40 CFR 63.10(d)(5)(ii) and including
a ``no'' in column 5. Section 63.10(d)(5)(ii) describes an immediate
report for SSM events when a source failed to meet an applicable
standard but did not follow the SSM plan. The EPA will no longer
require owners or operators to report when actions taken during an SSM
event were not consistent with an SSM plan, because plans would no
longer be required.
    Also, the EPA is removing and reserving 40 CFR 63.2281(e)(1) which
required reporting of the date and time when each malfunction started
and stopped. As discussed in section IV.C.4.f of this preamble,
reporting is required for deviations from the applicable standard as
opposed to every malfunction occurrence regardless of whether it
results in a failure to meet the standard. Section 40 CFR 63.2281(e)(4)
requires reporting of the date and time each deviation started and
stopped, and whether each deviation occurred during a period of SSM.

D. Electronic Reporting

    The EPA proposed that owners or operators of PCWP facilities submit
electronic copies of required performance test reports, performance
evaluation reports for continuous monitoring systems (CMS) measuring
relative accuracy test audit (RATA) pollutants (i.e., total hydrocarbon
monitors), selected notifications, and semiannual reports through the
EPA's Central Data Exchange (CDX) using the CEDRI. The EPA proposed
that performance test results collected using test methods that are
supported by the EPA's Electronic Reporting Tool (ERT) as listed on the
ERT website \5\ at the time of the test be submitted in the format
generated through the use of the ERT and that other performance test
results be submitted in portable document format (PDF) using the
attachment module of the ERT. Similarly, performance evaluation results
of CMS measuring RATA pollutants that are supported by the ERT at the
time of the test would be submitted in the format generated through the
use of the ERT and other performance evaluation results be submitted in
PDF using the attachment module of the ERT.
---------------------------------------------------------------------------

    \5\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------

    For the PCWP semiannual report, the EPA proposed that owners or
operators use a spreadsheet template to submit information to CEDRI. A
draft version of the spreadsheet template for this report was included
in the docket for the proposed rulemaking and the EPA specifically
requested comment on its content, layout, and overall design.\6\ The
EPA also proposed to require future initial notifications developed
according to 40 CFR 63.2280(b) and notifications of compliance status
developed according to 40 CFR 63.2280(d) to be uploaded in CEDRI in a
user-specified (e.g., PDF) format. In addition, the EPA proposed two
broad circumstances in which electronic reporting extensions may be
granted. In both circumstances, the decision to accept the claim of
needing additional time to report is within the discretion of the
Administrator, and reporting should occur as soon as possible. The EPA
proposed these potential extensions to protect owners or operators from
noncompliance in cases where they cannot successfully submit a report
by the reporting deadline for reasons

outside of their control. The situation where an extension may be
warranted due to outages of the EPA's CDX or CEDRI which precludes an
owner or operator from accessing the system and submitting required
reports is addressed in 40 CFR 63.2281(k). The situation where an
extension may be warranted due to a force majeure event, which is
defined as an event that will be or has been caused by circumstances
beyond the control of the affected facility, its contractors, or any
entity controlled by the affected facility that prevents an owner or
operator from complying with the requirement to submit a report
electronically as required by this rule is addressed in 40 CFR
63.2281(l). Examples of such events are acts of nature, acts of war or
terrorism, or equipment failure or safety hazards beyond the control of
the facility.
---------------------------------------------------------------------------

    \6\ See 40 CFR part 63, subpart DDDD--Plywood and Composite Wood
Products Semiannual Compliance Reporting Spreadsheet Template,
Docket Item No. EPA-HQ-OAR-2016-0243-0176.
---------------------------------------------------------------------------

    The EPA received several comments regarding the proposed electronic
reporting requirements, including favorable comments and comments
suggesting revisions. The electronic reporting requirements are
included in the final rule as proposed with clarification of specific
questions raised by commenters. Specific comments pertaining to the
draft spreadsheet template are detailed in the RTC document along with
the EPA's responses explaining how these comments were used to improve
the template. A revised version of the semiannual electronic reporting
spreadsheet template is available in the docket for the final rule.
    One commenter requested that the requirement to use a CEDRI form
should not begin until after the form has been available in CEDRI for
at least 1 year. The commenter also recommended that the transition to
using the new reporting form apply to an entire reporting period, not
come into effect in the middle of a reporting period and result in two
different reports being prepared. In response to this comment, we
revised the final rule to specify use of the semiannual reporting
template for the first full reporting period after it has been
available on the CEDRI website for 1 year. Refer to section IV.J of
this preamble for more discussion of the compliance timeline. The EPA
proposed a conforming amendment in Table 9 to 40 CFR part 63, subpart
DDDD, to require submittal of CMS performance evaluations according to
the electronic reporting provisions for performance evaluations
proposed in 40 CFR 63.2281(j). One commenter requested that the EPA
clarify that CMS performance evaluations should be submitted only for
continuous emission monitoring systems (CEMS) and not for continuous
parameter monitoring systems. In response to these requests for
clarification, we revised Table 9 to subpart DDDD to refer to state the
CMS performance evaluation to be reported is the performance evaluation
required for CEMS under 40 CFR 63.2269(d)(2). As discussed in section
IV.G of this preamble, for the final rule, we also revised Table 10 of
subpart DDDD to clarify that the CMS performance evaluation provisions
in 40 CFR 63.8(e) and the RATA provisions in 40 CFR 63.8(f)(6) only
apply for CEMS under subpart DDDD.

E. Repeat Emissions Testing

    As part of an ongoing effort to improve compliance with federal air
emission regulations, the EPA reviewed the emissions testing
requirements of 40 CFR part 63, subpart DDDD, and proposed to require
facilities complying with the standards in Table 1B of 40 CFR part 63,
subpart DDDD, using an add-on control system other than a biofilter to
conduct repeat emissions performance testing every 5 years. Currently,
facilities operating add-on controls are required to conduct an initial
performance test by the date specified in 40 CFR 63.2261(a). In
addition to the initial performance test, process units controlled by
biofilters are already required by the PCWP NESHAP to conduct repeat
performance testing every 2 years. Periodic performance tests for all
types of control systems are already required by permitting authorities
for many facilities. Further, the EPA believes that requiring repeat
performance tests will help to ensure that control systems are properly
maintained over time. As proposed in Table 7 to 40 CFR part 63, subpart
DDDD (row 7), the first of the repeat performance tests would be
required to be conducted within 3 years of the effective date of the
revised standards or within 5 years (60 months) following the previous
performance test, whichever is later, and thereafter within 60 months
following the previous performance test. Section IV.J of this preamble
provides more information on compliance dates.
    The EPA specifically requested comments on the proposed
requirements for repeat performance testing. One commenter agreed with
the proposed requirements and stated they are well supported and
legally required as part of meeting the EPA's statutory obligations.
The EPA received other comments requesting clarification of the
requirements surrounding repeat testing. One commenter requested
clarification with regards to whether the repeat testing is to include
press capture efficiency testing and requested due to cost, that repeat
press capture efficiency testing only be required if an alteration has
been made to the enclosure that would significantly affect its
efficacy. In response to this comment, a footnote was added to Table 7
to 40 CFR part 63, subpart DDDD, clarifying that capture efficiency
demonstration is not required with repeat performance tests if the
capture device is maintained and operated consistent with its design as
well as its operation during the previous capture efficiency
demonstration conducted according to Table 4 to subpart DDDD, row 9 as
specified in 40 CFR 63.2267.\7\ Aside from this clarification, the
proposed requirements for repeat emissions testing every 5 years for
add-on controls other than biofilters are included in the final rule as
proposed.
---------------------------------------------------------------------------

    \7\ The footnote added to Table 7 to 40 CFR part 63, subpart
DDDD, clarifying when capture efficiency testing is required was
included for biofilters and other control devices undergoing repeat
emissions testing.
---------------------------------------------------------------------------

    Two commenters requested more flexibility for catalytic oxidizer
catalyst checks required by the rule given the added repeat testing
requirements. The commenters requested the frequency of catalyst checks
be revised to ``annual'' or no more than every 15 months and requested
the requirement for catalyst checks be eliminated during years when
emissions tests are conducted. In response to these comments, the EPA
revised Tables 2 and 7 to 40 CFR part 63, subpart DDDD, to refer to
``annual'' catalyst checks and included a footnote stating that
facilities may forego the annual catalyst activity check during the
calendar year when a performance test conducted according to Table 4 to
subpart DDDD. The final rule requires that, in each calendar year,
either a performance test or a catalyst activity check must be
conducted.
    One commenter requested clarification that the Notification of
Compliance Status (NCS) is only required with the initial performance
test, not with each repeat performance test. As explained further in
the RTC document, a NCS is required with initial and repeat performance
tests under 40 CFR 63.9. In response to this comment, the EPA deleted
the word ``initial'' from 40 CFR 63.2280(d) and added a phrase
mentioning the ``repeat performance test as specified in Table 7 to
this subpart'' so it is clearer that a NCS is required when performing
repeat testing according to the methods in Table 4 to 40 CFR part 63,
subpart DDDD. The EPA also deleted the word ``initial'' and added a
reference to Table 7 to subpart DDDD (which includes repeat testing in

rows 3 and 7) to 40 CFR 63.2280(d)(2) and clarified that the NCS only
needs to have ``a summary of'' the performance test results submitted
according to the electronic performance test reporting provisions in 40
CFR 63.2281(i).

F. Biofilter Bed Temperature

    Facilities using a biofilter to comply with the PCWP NESHAP must
monitor biofilter bed temperature and maintain the 24-hour block
biofilter bed temperature within the range established during
performance testing showing compliance with the emission limits. As
originally promulgated, the upper and lower limits of the biofilter bed
temperature were required to be established as the highest and lowest
15-minute average bed temperatures, respectively, during the three test
runs. Facilities may conduct multiple performance tests to expand the
biofilter bed operating temperature range. See 40 CFR 63.2262(m).
    The EPA learned that multiple facilities are having difficulty
complying with the PCWP biofilter bed temperature monitoring
requirements established according to the original rule. Biofilter bed
temperature is affected by ambient temperature which cannot always be
accurately predicted in advance of scheduling performance tests. In
consideration of this issue, as discussed in the preamble for the
proposed amendments (at 84 FR 47097), the EPA proposed to revise 40 CFR
63.2262(m)(1) to add a 5-percent variability margin to the biofilter
bed temperature upper and lower limits established during emissions
testing.
    Commenters on the proposal stated that the proposed 5-percent
variability margin is insufficient, particularly on the lower end of
the biofilter bed temperature range and recommended instead that the
EPA provide a wider margin allowance or extend the operating limit
averaging period beyond the current 24-hour period. The commenters
stated that, unlike other common air pollution control devices with
operating parameters that can be controlled within a small percentage
of set point and are not subject to ambient atmospheric conditions,
biofilters are influenced by diurnal, day-to-day, and seasonal ambient
temperature variations because they are typically located outside due
to their size. They further stated that in practical terms, in order to
set the widest bed temperature range, a facility must test on the
coldest and the hottest day of the year, yet predicting those days is
not possible and is further complicated by the fact that stack test
teams and permitting agencies must be given months of advance notice
when scheduling a test.
    To address the commenters' concern that a 5-percent variability
margin is insufficient, the EPA increased the variability margin to 10
percent for the final rule with the stipulation that the variability
margin not exceed 8 degrees Fahrenheit ([deg]F) on the upper end of the
biofilter bed range. As noted in the memorandum, Review of Select
Biofilter/Bioscrubber Data Submitted in Response to the Plywood and
Composite Wood Products Information Collection Request, Docket Item No.
EPA-HQ-OAR-2016-0243-0188, the biofilter bed temperature across all of
the biofilters in the PCWP industry spans from 40 [deg]F to 150 [deg]F.
On the low end of this range, 5 percent is 2 [deg]F while 10 percent is
4 [deg]F. On the high end of the range, 5 percent is 8 [deg]F while 10
percent is 15 [deg]F. The upper-end value of 15 [deg]F added to 150
[deg]F would allow the facility to operate at 165 [deg]F, which the EPA
considers excessive in the absence of data showing this temperature is
not detrimental to the microbial population. Therefore, for the final
rule, the EPA capped the variability margin for the high end of the
biofilter bed temperature range at 8 [deg]F (which coincides with the
margin proposed). Thus, for the high-end biofilter bed temperature,
facilities may add up to 10 percent, not to exceed 8 [deg]F.
    The EPA anticipates that facilities currently having difficulty
maintaining the biofilter bed temperature limits may wish to adjust
their temperature limits. As originally promulgated, 40 CFR
63.2262(m)(1) states that facilities may base their biofilter bed
temperature range on values recorded during previous performance tests
provided that the data used to establish the temperature ranges have
been obtained using the required test methods; and that facilities
using data from previous performance tests must certify that the
biofilter and associated process unit(s) have not been modified since
the test. This provision (if met) clarifies that facilities can adjust
their previously established biofilter temperature range to include the
5-percent variability margin, if desired.

G. Thermocouple Calibration

    At 40 CFR 63.2269(b)(4), the PCWP NESHAP currently requires
conducting an electronic calibration of the temperature monitoring
device at least semiannually according to the procedures in the
manufacturer's owner's manual. Stakeholders with facilities subject to
the standard explained to the EPA that they are unaware of a
thermocouple manufacturer that provides procedures for conducting
electronic calibration of thermocouples. According to stakeholders,
facilities have been replacing thermocouples because they cannot
electronically calibrate them. The stakeholders requested the EPA
consider an alternative approach to the current requirement in 40 CFR
63.2269(b)(4). To address this issue, the EPA proposed revisions to 40
CFR 63.2269(b)(4) to allow multiple alternative approaches to
thermocouple validation.
    The EPA received comments supporting the proposed revisions to 40
CFR 63.2269(b)(4) and we are promulgating these revisions as proposed
with minor clarifications. In response to a comment that the word
``calibration'' be removed from 40 CFR 63.2269(b)(5), the EPA is
amending this paragraph to replace ``calibration and validation
checks'' with ``validation checks'' and to specify that validation
checks be conducted using the procedures in 40 CFR 63.2269(b)(4). One
commenter requested the EPA to clarify that temperature sensor
validations are not performance evaluations requiring formal