[Federal Register Volume 84, Number 173 (Friday, September 6, 2019)]
[Proposed Rules]
[Pages 47074-47114]
[FR Doc No: 2019-18827]

Vol. 84

Friday,

No. 173

September 6, 2019

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; Proposed
Rule

Federal Register / Vol. 84 , No. 173 / Friday, September 6, 2019 /
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2016-0243; FRL-9999-07-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: Proposed rule.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing
amendments to the National Emissions Standards for Hazardous Air
Pollutants (NESHAP) for Plywood and Composite Wood Products (PCWP) to
address the results of the residual risk and technology review (RTR)
that the EPA is required to conduct under the Clean Air Act (CAA). The
EPA is proposing to amend provisions addressing periods of startup,
shutdown and malfunction (SSM); add provisions regarding electronic
reporting; add repeat emissions testing requirements; and make
technical and editorial changes. The EPA is proposing these amendments
to improve the effectiveness of the NESHAP. While the proposed
amendments would not result in reductions in emissions of hazardous air
pollutants (HAP), this action, if finalized, would result in improved
monitoring, compliance, and implementation of the rule.

DATES:
    Comments. Comments must be received on or before October 21, 2019.
Under the Paperwork Reduction Act (PRA), comments on the information
collection provisions are best assured of consideration if the Office
of Management and Budget (OMB) receives a copy of your comments on or
before October 7, 2019.
    Public hearing. If anyone contacts us requesting a public hearing
on or before September 11, 2019, the EPA will hold a hearing.
Additional information about the hearing, if requested, will be
published in a subsequent Federal Register document and posted at
https://www.epa.gov/stationary-sources-air-pollution/plywood-and-composite-wood-products-manufacture-national-emission. See
SUPPLEMENTARY INFORMATION for information on requesting and registering
for a public hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2016-0243, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/
(our preferred method). Follow the online instructions for submitting
comments.
     Email<EMAIL_ADDRESS>Include Docket ID No. EPA-
HQ-OAR-2016-0243 in the subject line of the message.
     Fax:<PHONE_NUMBER>. Attention Docket ID No. EPA-HQ-OAR-
2016-0243.
     Mail: U.S. Environmental Protection Agency, EPA Docket
Center, Environmental Protection Agency Docket ID No. EPA-HQ-OAR-2016-
0243, Mail Code 28221T, 1200 Pennsylvania Avenue NW, Washington, DC
20460.
     Hand/Courier Delivery: EPA Docket Center, WJC West
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004.
The Docket Center's hours of operation are 8:30 a.m.-4:30 p.m.,
Monday--Friday (except federal holidays).
    Instructions: All submissions received must include the Docket ID
No. for this rulemaking. Comments received may be posted without change
to https://www.regulations.gov/, including any personal information
provided. For detailed instructions on sending comments and additional
information on the rulemaking process, see the SUPPLEMENTARY
INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed
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: (919)
541-0881; fax number:<PHONE_NUMBER>; and email address:
<EMAIL_ADDRESS>For questions about monitoring and testing
requirements, contact Mr. Kevin McGinn, Sector Policies and Programs
Division (D230-02), 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 (Mail Code 2221A), 1200
Pennsylvania Avenue NW, Washington, DC 20460; telephone number: (202)
564-1395; and email address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:
    Public hearing. Please contact Ms. Virginia Hunt at<PHONE_NUMBER>
or by email at<EMAIL_ADDRESS>to request a public hearing, to
register to speak at the public hearing, or to inquire as to whether a
public hearing will be held.
    Docket. The EPA has established a docket for this rulemaking under
Docket ID No. EPA-HQ-OAR-2016-0243. All documents in the docket are
listed in Regulations.gov. Although listed, some information is not
publicly available, e.g., Confidential Business Information (CBI) or
other information whose disclosure is restricted by statute. Certain
other material, such as copyrighted material, is not placed on the
internet and will be publicly available only in hard copy. Publicly
available docket materials are available either electronically in
Regulations.gov or in hard copy at the EPA Docket Center, Room 3334,
WJC West Building, 1301 Constitution Avenue NW, Washington, DC. The
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room is<PHONE_NUMBER>, and the telephone number for the EPA
Docket Center is<PHONE_NUMBER>.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2016-0243. The EPA's policy is that all comments received will be
included in the public docket without change and may be made available
online at https://www.regulations.gov/, including any personal
information provided, unless the comment includes information claimed
to be CBI or other information whose disclosure is restricted by
statute. Do not submit information that you consider to be CBI or
otherwise protected through https://www.regulations.gov/ or email. This
type of information should be submitted by mail as discussed below.
    The EPA may publish any comment received to its public docket.
Multimedia submissions (audio, video, etc.) must be accompanied by a
written comment. The written comment is considered the official comment
and should include discussion of all points

you wish to make. The EPA will generally not consider comments or
comment contents located outside of the primary submission (i.e., on
the Web, cloud, or other file sharing system). For additional
submission methods, the full EPA public comment policy, information
about CBI or multimedia submissions, and general guidance on making
effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
    The https://www.regulations.gov/ website allows you to submit your
comment anonymously, which means the EPA will not know your identity or
contact information unless you provide it in the body of your comment.
If you send an email comment directly to the EPA without going through
https://www.regulations.gov/, your email address will be automatically
captured and included as part of the comment that is placed in the
public docket and made available on the internet. If you submit an
electronic comment, the EPA recommends that you include your name and
other contact information in the body of your comment and with any
digital storage media you submit. If the EPA cannot read your comment
due to technical difficulties and cannot contact you for clarification,
the EPA may not be able to consider your comment. Electronic files
should not include special characters or any form of encryption and be
free of any defects or viruses. For additional information about the
EPA's public docket, visit the EPA Docket Center homepage at https://www.epa.gov/dockets.
    Submitting CBI. Do not submit information containing CBI to the EPA
through https://www.regulations.gov/ or email. Clearly mark the part or
all of the information that you claim to be CBI. For CBI information on
any digital storage media that you mail to the EPA, mark the outside of
the digital storage media as CBI and then identify electronically
within the digital storage media the specific information that is
claimed as CBI. In addition to one complete version of the comments
that includes information claimed as CBI, you must submit a copy of the
comments that does not contain the information claimed as CBI directly
to the public docket through the procedures outlined in Instructions
above. If you submit any digital storage media that does not contain
CBI, mark the outside of the digital storage media clearly that it does
not contain CBI. Information not marked as CBI will be included in the
public docket and the EPA's electronic public docket without prior
notice. Information marked as CBI will not be disclosed except in
accordance with procedures set forth in 40 Code of Federal Regulations
(CFR) part 2. Send or deliver information identified as CBI only to the
following address: OAQPS Document Control Officer (C404-02), OAQPS,
U.S. Environmental Protection Agency, Research Triangle Park, North
Carolina 27711, Attention Docket ID No. EPA-HQ-OAR-2016-0243.
    Preamble acronyms and abbreviations. The EPA uses multiple acronyms
and terms in this preamble. While this list may not be exhaustive, to
ease the reading of this preamble and for reference purposes, the EPA
defines the following terms and acronyms here:

AEGL acute exposure guideline level
AERMOD air dispersion model used by the HEM-3 model
ATCM Airborne Toxic Control Measure
ATSDR Agency for Toxic Substances and Disease Registry
CAA Clean Air Act
CalEPA California EPA
CARB California Air Resources Board
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
CMS continuous monitoring systems
EAV equivalent annualized value
EPA Environmental Protection Agency
ERPG Emergency Response Planning Guideline
ERT Electronic Reporting Tool
GACT generally available control technology
HAP hazardous air pollutant(s)
HCl hydrochloric acid
HEM-3 Human Exposure Model-3
HF hydrogen fluoride
HI hazard index
HQ hazard quotient
ICR information collection request
IRIS Integrated Risk Information System
km kilometer
MACT maximum achievable control technology
MDF medium density fiberboard
mg/m\3\ milligrams per cubic meter
MIR maximum individual risk
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NEI National Emissions Inventory
NESHAP national emission standards for hazardous air pollutants
NIST National Institute of Standards and Technology
NRDC Natural Resources Defense Council
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
OSB oriented Strandboard
OSHA Occupational Safety and Health Administration
PBCO production-based compliance option
PB-HAP hazardous air pollutants known to be persistent and bio-
accumulative in the environment
PCWP plywood and composite wood products
PDF portable document format
POM polycyclic organic matter
ppm parts per million
PRA Paperwork Reduction Act
PV present value
RATA relative accuracy test audit
RCO regenerative catalytic oxidizer
REL reference exposure level
RFA Regulatory Flexibility Act
RfC reference concentration
RfD reference dose
RTO regenerative thermal oxidizer
RTR residual risk and technology review
SAB Science Advisory Board
SSM startup, shutdown, and malfunction
TOSHI target organ-specific hazard index
tpy tons per year
TRIM.FaTE Total Risk Integrated Methodology. Fate, Transport, and
Ecological Exposure model
TSCA Toxic Substances Control Act
UF uncertainty factor
[mu]g/m\3\ microgram per cubic meter
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
USGS U.S. Geological Survey
VCS voluntary consensus standards

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

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related
information?
II. Background
    A. What is the statutory authority for this action?
    B. What is this source category and how does the current NESHAP
regulate its HAP emissions?
    C. What data collection activities were conducted to support
this action?
    D. What other relevant background information and data are
available?
III. Analytical Procedures and Decision-Making
    A. How do we consider risk in our decision-making?
    B. How do we perform the technology review?
    C. How do we estimate post-MACT risk posed by the source
category?
IV. Analytical Results and Proposed Decisions
    A. What are the results of the risk assessment and analyses?
    B. What are our proposed decisions regarding risk acceptability,
ample margin of safety, and adverse environmental effect?
    C. What are the results and proposed decisions based on our
technology review?
    D. What other actions are we proposing?
    E. What compliance dates are we proposing?
V. Summary of Cost, Environmental, and Economic Impacts
    A. What are the affected sources?
    B. What are the air quality impacts?

    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
VI. Request for Comments
VII. Submitting Data Corrections
VIII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Executive Order 13771: Reducing Regulation and Controlling
Regulatory Costs
    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)
    K. Executive Order 12898: Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations

I. General Information

A. Does this action apply to me?

    Table 1 of this preamble lists the NESHAP and associated regulated
industrial source category that is the subject of this proposal. Table
1 is not intended to be exhaustive, but rather provides a guide for
readers regarding the entities that this proposed action is likely to
affect. The proposed standards, once promulgated, will be directly
applicable to the affected sources. Federal, state, local, and tribal
government entities would not be affected by this proposed action. As
defined in the Initial List of Categories of Sources Under Section
112(c)(1) of the Clean Air Act Amendments of 1990 (see 57 FR 31576,
July 16, 1992) and Documentation for Developing the Initial Source
Category List, Final Report (see EPA-450/3-91-030, July 1992), the
Plywood and Particleboard source category is any facility engaged in
the manufacturing of plywood and/or particle boards. This category
includes, but is not limited to, manufacturing of chip waferboard,
strandboard, waferboard, hardboard/cellulosic fiber board, oriented
strandboard (OSB), hardboard plywood, medium density fiberboard (MDF),
particleboard, softwood plywood, or other processes using wood and
binder systems. The name of the source category was changed to Plywood
and Composite Wood Products (PCWP) on November 18, 1999 (64 FR 63025),
to more accurately reflect the types of manufacturing facilities
covered by the source category. In addition, when the EPA proposed the
PCWP rule on January 9, 2003 (68 FR 1276), the scope of the source
category was broadened to include lumber kilns located at stand-alone
kiln-dried lumber manufacturing facilities or at any other type of
facility.

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

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

    In addition to being available in the docket, an electronic copy of
this action is available on the internet. Following signature by the
EPA Administrator, the EPA will post a copy of this proposed action at
https://www.epa.gov/plywood-and-composite-wood-products-manufacture-national-emission. Following publication in the Federal Register, the
EPA will post the Federal Register version of the proposal and key
technical documents at this same website. Information on the overall
RTR program is available at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.
    A redline version of the regulatory language that incorporates the
proposed changes in this action is available in the docket for this
action (Docket ID No. EPA-HQ-OAR-2016-0243).

II. Background

A. What is the statutory authority for this action?

    The statutory authority for this action is provided by sections 112
and 301 of the CAA, as amended (42 U.S.C. 7401 et seq.). Section 112 of
the CAA establishes a two-stage regulatory process to develop standards
for emissions of HAP from stationary sources. Generally, the first
stage involves establishing technology-based standards and the second
stage involves evaluating those standards that are based on maximum
achievable control technology (MACT) to determine whether additional
standards are needed to address any remaining risk associated with HAP
emissions. This second stage is commonly referred to as the ``residual
risk review.'' In addition to the residual risk review, the CAA also
requires the EPA to review standards set under CAA section 112 every 8
years to determine if there are ``developments in practices, processes,
or control technologies'' that may be appropriate to incorporate into
the standards. This review is commonly referred to as the ``technology
review.'' When the two reviews are combined into a single rulemaking,
it is commonly referred to as the ``risk and technology review.'' The
discussion that follows identifies the most relevant statutory sections
and briefly explains the contours of the methodology used to implement
these statutory requirements. A more comprehensive discussion appears
in the document titled CAA Section 112 Risk and Technology Reviews:
Statutory Authority and Methodology, in the docket for this rulemaking.
    In the first stage of the CAA section 112 standard setting process,
the EPA promulgates technology-based standards under CAA section 112(d)
for categories of sources identified as emitting one or more of the HAP
listed in CAA section 112(b). Sources of HAP emissions are either major
sources or area sources, and CAA section 112 establishes different
requirements for major source standards and area source standards.
``Major sources'' are those that emit or have the potential to emit 10
tons per year (tpy) or more of a single HAP or 25 tpy or more of any
combination of HAP. All other sources are ``area sources.'' For major
sources, CAA section 112(d)(2) provides that the technology-based
NESHAP must reflect the maximum degree of emission reductions of HAP
achievable (after considering cost, energy requirements, and non-air
quality health and environmental impacts). These standards are commonly
referred to as MACT standards. CAA section 112(d)(3) also

establishes a minimum control level for MACT standards, known as the
MACT ``floor.'' The EPA must also consider control options that are
more stringent than the floor. Standards more stringent than the floor
are commonly referred to as beyond-the-floor standards. In certain
instances, as provided in CAA section 112(h), the EPA may set work
practice standards where it is not feasible to prescribe or enforce a
numerical emission standard. For area sources, CAA section 112(d)(5)
gives the EPA discretion to set standards based on generally available
control technologies or management practices (GACT standards) in lieu
of MACT standards.
    The second stage in standard-setting focuses on identifying and
addressing any remaining (i.e., ``residual'') risk according to CAA
section 112(f). For source categories subject to MACT standards,
section 112(f)(2) of the CAA requires the EPA to determine whether
promulgation of additional standards is needed to provide an ample
margin of safety to protect public health or to prevent an adverse
environmental effect. Section 112(d)(5) of the CAA provides that this
residual risk review is not required for categories of area sources
subject to GACT standards. Section 112(f)(2)(B) of the CAA further
expressly preserves the EPA's use of the two-step approach for
developing standards to address any residual risk and the Agency's
interpretation of ``ample margin of safety'' developed in the National
Emissions Standards for Hazardous Air Pollutants: Benzene Emissions
from Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene
Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery
Plants (Benzene NESHAP) (54 FR 38044, September 14, 1989). The EPA
notified Congress in the Risk Report that the Agency intended to use
the Benzene NESHAP approach in making CAA section 112(f) residual risk
determinations (EPA-453/R-99-001, p. ES-11). The EPA subsequently
adopted this approach in its residual risk determinations and the
United States Court of Appeals for the District of Columbia Circuit
(the Court) upheld the EPA's interpretation that CAA section 112(f)(2)
incorporates the approach established in the Benzene NESHAP. See NRDC
v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008).
    The approach incorporated into the CAA and used by the EPA to
evaluate residual risk and to develop standards under CAA section
112(f)(2) is a two-step approach. In the first step, the EPA determines
whether risks are acceptable. This determination ``considers all health
information, including risk estimation uncertainty, and includes a
presumptive limit on maximum individual lifetime [cancer] risk (MIR)
\1\ of approximately 1 in 10 thousand.'' 54 FR 38045, September 14,
1989. If risks are unacceptable, the EPA must determine the emissions
standards necessary to reduce risk to an acceptable level without
considering costs. In the second step of the approach, the EPA
considers whether the emissions standards provide an ample margin of
safety to protect public health ``in consideration of all health
information, including the number of persons at risk levels higher than
approximately 1 in 1 million, as well as other relevant factors,
including costs and economic impacts, technological feasibility, and
other factors relevant to each particular decision.'' Id. The EPA must
promulgate emission standards necessary to provide an ample margin of
safety to protect public health or determine that the standards being
reviewed provide an ample margin of safety without any revisions. After
conducting the ample margin of safety analysis, the EPA considers
whether a more stringent standard is necessary to prevent, taking into
consideration costs, energy, safety, and other relevant factors, an
adverse environmental effect.
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    \1\ Although defined as ``maximum individual risk,'' MIR refers
only to cancer risk. MIR, one metric for assessing cancer risk, is
the estimated risk if an individual were exposed to the maximum
level of a pollutant for a lifetime.
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    CAA section 112(d)(6) separately requires the EPA to review
standards promulgated under CAA section 112 and revise them ``as
necessary (taking into account developments in practices, processes,
and control technologies)'' no less often than every 8 years. In
conducting this review, which the EPA calls the ``technology review,''
the EPA is not required to recalculate the MACT floor. Natural
Resources Defense Council (NRDC) v. EPA, 529 F.3d 1077, 1084 (D.C. Cir.
2008). Association of Battery Recyclers, Inc. v. EPA, 716 F.3d 667
(D.C. Cir. 2013). The EPA may consider cost in deciding whether to
revise the standards pursuant to CAA section 112(d)(6).

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

    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. Plywood and composite wood products
manufacturing facilities also include facilities that manufacture dry
veneer and lumber kilns located at any facility. Plywood and composite
wood products include (but are not limited to) plywood, veneer,
particleboard, OSB, hardboard, fiberboard, medium density fiberboard,
laminated strand lumber, laminated veneer lumber, wood I-joists, kiln-
dried lumber, and glue-laminated beams.
    This proposal includes both a residual risk assessment and a
technology review of the standards applicable to emission sources
subject to the PCWP NESHAP. 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 produced; 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).
    In 2007, the D.C. Circuit remanded and vacated portions of the 2004
NESHAP promulgated by the EPA to establish MACT standards for the PCWP
source category. NRDC v. EPA, 489 F.3d 1364 (D.C. Cir. 2007). The EPA
will address the partial remand and vacatur of the 2004 rule in a
future action. The EPA is not addressing the partial remand and vacatur
in this RTR. The Court vacated and remanded portions of the 2004 rule
based on certain aspects of the MACT determinations made by the EPA. In
the 2004 rule, the EPA had concluded that the MACT standards for
several process units were represented by no emission reduction (or
``no control'' emission floors). The ``no control'' MACT conclusions
were rejected because, as the Court clarified, in a related decision,
the EPA must establish emission standards for listed HAP. 489 F.3d
1364, 1371, citing Sierra

Club v. EPA, 479 F.3d 875 (D.C. Cir. 2007).
    To address the remand, the EPA plans to develop emission standards
for the relevant process units in a separate action subsequent to this
proposed RTR action for the source category. As noted below, the EPA
conducted an information collection prior to beginning the RTR process
which supplemented the available HAP emission inventory for the
category. The EPA will evaluate the data collected and any additional
information submitted before initiating the rulemaking to address the
remand.

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

    On October 5, 2017, the EPA issued an Information Collection
Request (ICR) to gather information from PCWP manufacturers to support
conducting the PCWP NESHAP RTR. The ICR gathered detailed process data,
emission release point characteristics, and HAP emissions data for PCWP
process units located at major sources. The response rate for the ICR
was over 99 percent. For more details on the data collection conducted
to prepare inputs for the residual risk assessment, see the memorandum
titled Preparation of the Residual Risk Modeling Inputs File for the
PCWP NESHAP in the docket for this rulemaking. For more details on the
data collection conducted for the technology review, see the memoranda
titled Technology Review for the Plywood and Composite Wood Products
NESHAP and Compilation of the Plywood and Composite Wood Products
(PCWP) Information Collection Request (ICR) Responses into an ICR-
Response Data Base, also available in the docket.

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

    In addition to ICR data spreadsheets provided by respondents, the
EPA reviewed other information sources to determine if there have been
developments in practices, processes, or control technologies by PCWP
facilities to support the technology review of the NESHAP. These
information sources include:
     Emissions data (e.g., stack test reports, emissions
calculations) submitted with survey responses;
     Facility operating permits submitted with survey responses
or obtained from state agencies;
     Semiannual compliance reports submitted with survey
responses;
     Other documentation submitted with survey responses (e.g.,
compliance calculations; process flow diagrams);
     Information and data analyses submitted by industry
organizations;
     Information obtained during site visits and meetings with
stakeholders;
     Information on air pollution control options in the PCWP
industry from the EPA's Reasonably Available Control Technology/Best
Available Control Technology/Lowest Achievable Emission Rate
Clearinghouse;
     Information on applicability and compliance issues from
the EPA's Applicability Determination Index; and
     Literature review of recent information on PCWP practices,
processes, and control technologies.

III. Analytical Procedures and Decision-Making

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

A. How do we consider risk in our decision-making?

    As discussed in section II.A of this preamble and in the Benzene
NESHAP, in evaluating and developing standards under CAA section
112(f)(2), the EPA applies a two-step approach to determine whether or
not risks are acceptable and to determine if the standards provide an
ample margin of safety to protect public health. As explained in the
Benzene NESHAP, ``the first step judgment on acceptability cannot be
reduced to any single factor'' and, thus, ``[t]he Administrator
believes that the acceptability of risk under section 112 is best
judged on the basis of a broad set of health risk measures and
information.'' 54 FR 38046, September 14, 1989. Similarly, with regard
to the ample margin of safety determination, ``the Agency again
considers all of the health risk and other health information
considered in the first step. Beyond that information, additional
factors relating to the appropriate level of control will also be
considered, including cost and economic impacts of controls,
technological feasibility, uncertainties, and any other relevant
factors.'' Id.
    The Benzene NESHAP approach provides flexibility regarding factors
the EPA may consider in making determinations and how the EPA may weigh
those factors for each source category. The EPA conducts a risk
assessment that provides estimates of the MIR posed by the HAP
emissions from each source in the source category, the hazard index
(HI) for chronic exposures to HAP with the potential to cause noncancer
health effects, and the hazard quotient (HQ) for acute exposures to HAP
with the potential to cause noncancer health effects.\2\ The assessment
also provides estimates of the distribution of cancer risk within the
exposed populations, cancer incidence, and an evaluation of the
potential for an adverse environmental effect. The scope of the EPA's
risk analysis is consistent with the EPA's response to comments on our
policy under the Benzene NESHAP where the EPA explained that:
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    \2\ The MIR is defined as the cancer risk associated with a
lifetime of exposure at the highest concentration of HAP where
people are likely to live. The HQ is the ratio of the potential HAP
exposure concentration to the noncancer dose-response value; the HI
is the sum of HQs for HAP that affect the same target organ or organ
system.

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

See 54 FR 38057, September 14, 1989. Thus, the level of the MIR is only
one factor to be weighed in determining acceptability of risk. The
Benzene NESHAP explained that ``an MIR of approximately one in 10
thousand should ordinarily be the upper end of the range of
acceptability. As risks increase above this benchmark, they become
presumptively less acceptable under CAA section 112, and would be
weighed with the other health risk measures and information in making
an overall judgment on acceptability. Or, the Agency may find, in a
particular case, that a risk that includes an MIR less than the
presumptively acceptable level is unacceptable in the light of other
health risk factors.'' Id. at 38045. In other words, risks that include
an MIR where 100-in-1 million may be determined to be acceptable and
risks with an MIR below that level may be determined to be
unacceptable, depending on all of the available information. Similarly,
with regard to the ample margin of safety analysis, the EPA stated in
the Benzene NESHAP that: ``EPA believes the relative weight

of the many factors that can be considered in selecting an ample margin
of safety can only be determined for each specific source category.
This occurs mainly because technological and economic factors (along
with the health-related factors) vary from source category to source
category.'' Id. at 38061. The EPA also considers the uncertainties
associated with the various risk analyses, as discussed earlier in this
preamble, in our determinations of acceptability and ample margin of
safety.
    The EPA notes that we have not considered certain health
information to date in making residual risk determinations. At this
time, the EPA does not attempt to quantify the HAP risk that may be
associated with emissions from other facilities that do not include the
source category under review, mobile source emissions, natural source
emissions, persistent environmental pollution, or atmospheric
transformation in the vicinity of the sources in the category.
    The EPA understands the potential importance of considering an
individual's total exposure to HAP in addition to considering exposure
to HAP emissions from the source category and facility. The EPA
recognizes that such consideration may be particularly important when
assessing noncancer risk, where pollutant-specific exposure health
reference levels (e.g., reference concentrations (RfCs)) are based on
the assumption that thresholds exist for adverse health effects. For
example, the EPA recognizes that, although exposures attributable to
emissions from a source category or facility alone may not indicate the
potential for increased risk of adverse noncancer health effects in a
population, the exposures resulting from emissions from the facility in
combination with emissions from all of the other sources (e.g., other
facilities) to which an individual is exposed may be sufficient to
result in an increased risk of adverse noncancer health effects. In May
2010, the Science Advisory Board (SAB) advised the EPA ``that RTR
assessments will be most useful to decision makers and communities if
results are presented in the broader context of aggregate and
cumulative risks, including background concentrations and contributions
from other sources in the area.'' \3\
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    \3\ Recommendations of the SAB Risk and Technology Review Panel
are provided in their report, which is available at: https://
yosemite.epa.gov/sab/sabproduct.nsf/
4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf.
---------------------------------------------------------------------------

    In response to the SAB recommendations, the EPA incorporates
cumulative risk analyses into its RTR risk assessments, including those
reflected in this proposal. The Agency (1) conducts facility-wide
assessments, which include source category emission points, as well as
other emission points within the facilities; (2) combines exposures
from multiple sources in the same category that could affect the same
individuals; and (3) for some persistent and bioaccumulative
pollutants, analyzes the ingestion route of exposure. In addition, the
RTR risk assessments consider aggregate cancer risk from all
carcinogens and aggregated noncancer HQs for all noncarcinogens
affecting the same target organ or target organ system.
    Although the EPA is interested in placing source category and
facility-wide HAP risk in the context of total HAP risk from all
sources combined in the vicinity of each source, we are concerned about
the uncertainties of doing so. Estimates of total HAP risk from
emission sources other than those that the EPA has studied in depth
during this RTR review would have significantly greater associated
uncertainties than the source category or facility-wide estimates. Such
aggregate or cumulative assessments would compound those uncertainties,
making the assessments too unreliable.

B. How do we perform the technology review?

    Our technology review focuses on the identification and evaluation
of developments in practices, processes, and control technologies that
have occurred since the MACT standards were promulgated. Where the EPA
identifies such developments, we analyze their technical feasibility,
estimated costs, energy implications, and non-air environmental
impacts. The EPA also considers the emission reductions associated with
applying each development. This analysis informs our decision of
whether it is ``necessary'' to revise the emissions standards. In
addition, the EPA considers the appropriateness of applying controls to
new sources versus retrofitting existing sources. For this exercise, we
consider any of the following to be a ``development'':
     Any add-on control technology or other equipment that was
not identified and considered during development of the original MACT
standards;
     Any improvements in add-on control technology or other
equipment (that were identified and considered during development of
the original MACT standards) that could result in additional emissions
reduction;
     Any work practice or operational procedure that was not
identified or considered during development of the original MACT
standards;
     Any process change or pollution prevention alternative
that could be broadly applied to the industry and that was not
identified or considered during development of the original MACT
standards; and
     Any significant changes in the cost (including cost
effectiveness) of applying controls (including controls the EPA
considered during the development of the original MACT standards).
    In addition to reviewing the practices, processes, and control
technologies that were considered at the time the EPA originally
developed the NESHAP, we review a variety of data sources in our
investigation of potential practices, processes, or controls to
consider. See sections II.C and II.D of this preamble for information
on the specific data sources that were reviewed as part of the
technology review.

C. How do we estimate post-MACT risk posed by the source category?

    In this section, we provide a complete description of the types of
analyses that the EPA generally performs during the risk assessment
process. In some cases, the EPA does not perform a specific analysis
because it is not relevant. For example, in the absence of emissions of
HAP known to be persistent and bioaccumulative in the environment (PB-
HAP), the EPA would not perform a multipathway exposure assessment.
Where the EPA does not perform an analysis, we state that we do not and
provide the reason. While we present all of our risk assessment
methods, we only present risk assessment results for the analyses
actually conducted (see section IV.A of this preamble).
    The EPA conducts a risk assessment that provides estimates of the
MIR for cancer posed by the HAP emissions from each source in the
source category, the HI for chronic exposures to HAP with the potential
to cause noncancer health effects, and the HQ for acute exposures to
HAP with the potential to cause noncancer health effects. The
assessment also provides estimates of the distribution of cancer risk
within the exposed populations, cancer incidence, and an evaluation of
the potential for an adverse environmental effect. The seven sections
that follow this paragraph describe how the EPA estimated emissions and
conducted the risk assessment. The docket for this rulemaking contains
the following document which provides more information on the risk
assessment

inputs and models: Residual Risk Assessment for the Plywood and
Composite Wood Products Source Category in Support of the 2019 Risk and
Technology Review Proposed Rule. The methods used to assess risk (as
described in the seven primary steps below) are consistent with those
described by the EPA in the document reviewed by a panel of the EPA's
SAB in 2009; \4\ and described in the SAB review report issued in 2010.
They are also consistent with the key recommendations contained in that
report.
---------------------------------------------------------------------------

    \4\ U.S. EPA. Risk and Technology Review (RTR) Risk Assessment
Methodologies: For Review by the EPA's Science Advisory Board with
Case Studies--MACT I Petroleum Refining Sources and Portland Cement
Manufacturing, June 2009. EPA-452/R-09-006. https://www3.epa.gov/airtoxics/rrisk/rtrpg.html.
---------------------------------------------------------------------------

1. How did we estimate actual emissions and identify the emissions
release characteristics?
    In October 2017, the EPA initiated an ICR to gather information
from U.S. PCWP manufacturers to support conducting the PCWP RTR. The
ICR response period ended in February 2018. The ICR gathered process
data, emission release point characteristics, coordinates, and HAP
emissions data for PCWP process units located at major sources of HAP.
Assembly and quality assurance of the ICR data needed to construct the
residual risk modeling file for the PCWP source category is discussed
in Preparation of Residual Risk Modeling Inputs File for the PCWP
NESHAP, which is available in the docket for this action.
2. How did we estimate MACT-allowable emissions?
    The available emissions data in the RTR emissions dataset include
estimates of the mass of HAP emitted during a specified annual time
period. These ``actual'' emission levels are often lower than the
emission levels allowed under the requirements of the current MACT
standards. The emissions allowed under the MACT standards are referred
to as the ``MACT-allowable'' emissions. The EPA discussed the
consideration of both MACT-allowable and actual emissions in the final
Coke Oven Batteries RTR (70 FR 19998-19999, April 15, 2005) and in the
proposed and final Hazardous Organic NESHAP RTR (71 FR 34428, June 14,
2006, and 71 FR 76609, December 21, 2006, respectively). In those
actions, the EPA noted that assessing the risk at the MACT-allowable
level is inherently reasonable since that risk reflects the maximum
level facilities could emit and still comply with national emission
standards. The EPA also explained that it is reasonable to consider
actual emissions, where such data are available, in both steps of the
risk analysis, in accordance with the Benzene NESHAP approach. (54 FR
38044, September 14, 1989.)
    The PCWP ICR requested that respondents provide estimates of
allowable emissions based on their site-specific circumstances (e.g.,
control measures in place). Therefore, unlike other RTR projects that
develop a multiplier to estimate allowable emissions from actual
emissions reported in the National Emissions Inventory (NEI), the
directly reported ICR data for allowable emissions were used for the
PCWP category.\5\
---------------------------------------------------------------------------

    \5\ Sroka, K., E. Rickman, and C. Moss, RTI, and K. Hanks, U.S.
EPA. Preparation of Residual Risk Modeling Inputs File for the PCWP
NESHAP. Memorandum to the PCWP Docket File. February 7, 2019.
---------------------------------------------------------------------------

    The allowable emissions estimates provided by the ICR respondents
were reviewed for completeness and to ensure they made sense relative
to actual emissions. Approximately 95 percent of the allowable
emissions estimates provided by respondents were reasonable and were
used without revision. The remaining allowable emission estimates were
either missing, provided as zero, or otherwise suspect compared to
actual emissions. Because nearly all the allowable emissions estimates
in need of gap-filling were for process units without PCWP MACT
standards requiring use of add-on controls, the gaps and adjustments
were completed by setting the MACT-allowable emission rates equal to
the actual emission rates.\6\
---------------------------------------------------------------------------

    \6\ Id.
---------------------------------------------------------------------------

3. How do we conduct dispersion modeling, determine inhalation
exposures, and estimate individual and population inhalation risk?
    Both long-term and short-term inhalation exposure concentrations
and health risk from the source category addressed in this proposal
were estimated using the Human Exposure Model (HEM-3).\7\ The HEM-3
performs three primary risk assessment activities: (1) Conducting
dispersion modeling to estimate the concentrations of HAP in ambient
air, (2) estimating long-term and short-term inhalation exposures to
individuals residing within 50 kilometers (km) of the modeled sources,
and (3) estimating individual and population-level inhalation risk
using the exposure estimates and quantitative dose-response
information.
---------------------------------------------------------------------------

    \7\ For more information about HEM-3, go to https://www.epa.gov/fera/risk-assessment-and-modeling-human-exposure-model-hem.
---------------------------------------------------------------------------

a. Dispersion Modeling
    The air dispersion model AERMOD, used by the HEM-3 model, is one of
the EPA's preferred models for assessing air pollutant concentrations
from industrial facilities.\8\ To perform the dispersion modeling and
to develop the preliminary risk estimates, HEM-3 draws on three data
libraries. The first is a library of meteorological data, which is used
for dispersion calculations. This library includes 1 year (2016) of
hourly surface and upper air observations from 824 meteorological
stations, selected to provide coverage of the United States and Puerto
Rico. A second library of United States Census Bureau census block \9\
internal point locations and populations provides the basis of human
exposure calculations (U.S. Census, 2010). In addition, for each census
block, the census library includes the elevation and controlling hill
height, which are also used in dispersion calculations. A third library
of pollutant-specific dose-response values is used to estimate health
risk. These are discussed below.
---------------------------------------------------------------------------

    \8\ U.S. EPA. Revision to the Guideline on Air Quality Models:
Adoption of a Preferred General Purpose (Flat and Complex Terrain)
Dispersion Model and Other Revisions (70 FR 68218, November 9,
2005).
    \9\ A census block is the smallest geographic area for which
census statistics are tabulated.
---------------------------------------------------------------------------

b. Risk From Chronic Exposure to HAP
    In developing the risk assessment for chronic exposures, the EPA
uses the estimated annual average ambient air concentrations of each
HAP emitted by each source in the source category. The HAP air
concentrations at each nearby census block centroid located within 50
km of the facility are a surrogate for the chronic inhalation exposure
concentration for all the people who reside in that census block. A
distance of 50 km is consistent with both the analysis supporting the
1989 Benzene NESHAP (54 FR 38044, September 14, 1989) and the
limitations of Gaussian dispersion models, including AERMOD.
    For each facility, the EPA calculates the MIR as the cancer risk
associated with a continuous lifetime (24 hours per day, 7 days per
week, 52 weeks per year, 70 years) exposure to the maximum
concentration at the centroid of each inhabited census block. The EPA
calculates individual cancer risk by multiplying the estimated lifetime
exposure to the ambient concentration of each HAP (in micrograms per
cubic meter ([mu]g/m\3\)) by its unit risk estimate

(URE). The URE is an upper-bound estimate of an individual's
incremental risk of contracting cancer over a lifetime of exposure to a
concentration of 1 microgram of the pollutant per cubic meter of air.
For residual risk assessments, the EPA generally uses UREs from the
EPA's Integrated Risk Information System (IRIS). For carcinogenic
pollutants without IRIS values, the EPA looks to other reputable
sources of cancer dose-response values, often using California EPA
(CalEPA) UREs, where available. In cases where new, scientifically
credible dose-response values have been developed in a manner
consistent with EPA guidelines and have undergone a peer review process
similar to that used by the EPA, the EPA may use such dose-response
values in place of, or in addition to, other values, if appropriate.
The pollutant-specific dose-response values used to estimate health
risk are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
    To estimate individual lifetime cancer risks associated with
exposure to HAP emissions from each facility in the source category,
the EPA sums the risks for each of the carcinogenic HAP \10\ emitted by
the modeled facility. The EPA estimates cancer risk at every census
block within 50 km of every facility in the source category. The MIR is
the highest individual lifetime cancer risk estimated for any of those
census blocks. In addition to calculating the MIR, the EPA estimates
the distribution of individual cancer risks for the source category by
summing the number of individuals within 50 km of the sources whose
estimated risk falls within a specified risk range. The EPA also
estimates annual cancer incidence by multiplying the estimated lifetime
cancer risk at each census block by the number of people residing in
that block, summing results for all of the census blocks, and then
dividing this result by a 70-year lifetime.
---------------------------------------------------------------------------

    \10\ The EPA's 2005 Guidelines for Carcinogen Risk Assessment
classifies carcinogens as: ``carcinogenic to humans,'' ``likely to
be carcinogenic to humans,'' and ``suggestive evidence of
carcinogenic potential.'' These classifications also coincide with
the terms ``known carcinogen, probable carcinogen, and possible
carcinogen,'' respectively, which are the terms advocated in the
EPA's Guidelines for Carcinogen Risk Assessment, published in 1986
(51 FR 33992, September 24, 1986). In August 2000, the document,
Supplemental Guidance for Conducting Health Risk Assessment of
Chemical Mixtures (EPA/630/R-00/002), was published as a supplement
to the 1986 document. Copies of both documents can be obtained from
https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=20533&CFID=70315376&CFTOKEN=71597944. Summing
the risk of these individual compounds to obtain the cumulative
cancer risk is an approach that was recommended by the EPA's SAB in
their 2002 peer review of the EPA's National Air Toxics Assessment
(NATA) titled NATA--Evaluating the National-scale Air Toxics
Assessment 1996 Data--an SAB Advisory, available at https://
yosemite.epa.gov/sab/sabproduct.nsf/
214C6E915BB04E14852570CA007A682C/$File/ecadv02001.pdf.
---------------------------------------------------------------------------

    To assess the risk of noncancer health effects from chronic
exposure to HAP, the EPA calculates either an HQ or a target organ-
specific hazard index (TOSHI). The EPA calculates an HQ when a single
noncancer HAP is emitted. Where more than one noncancer HAP is emitted,
the EPA sums the HQ for each of the HAP that affects a common target
organ or target organ system to obtain a TOSHI. The HQ is the estimated
exposure divided by the chronic noncancer dose-response value, which is
a value selected from one of several sources. The preferred chronic
noncancer dose-response value is the EPA RfC, defined as ``an estimate
(with uncertainty spanning perhaps an order of magnitude) of a
continuous inhalation exposure to the human population (including
sensitive subgroups) that is likely to be without an appreciable risk
of deleterious effects during a lifetime'' (https://iaspub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&vocabName=IRIS%20Glossary). In cases where an RfC
from the EPA's IRIS is not available or where the EPA determines that
using a value other than the RfC is appropriate, the chronic noncancer
dose-response value can be a value from the following prioritized
sources, which define their dose-response values similarly to the EPA:
(1) The Agency for Toxic Substances and Disease Registry (ATSDR)
Minimum Risk Level (https://www.atsdr.cdc.gov/mrls/index.asp); (2) the
CalEPA Chronic Reference Exposure Level (REL) (https://oehha.ca.gov/air/crnr/notice-adoption-air-toxics-hot-spots-program-guidance-manual-preparation-health-risk-0); or (3) as noted above, a scientifically
credible dose-response value that has been developed in a manner
consistent with the EPA guidelines and has undergone a peer review
process similar to that used by the EPA. The pollutant-specific dose-
response values used to estimate health risks are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
c. Risk From Acute Exposure to HAP That May Cause Health Effects Other
Than Cancer
    For each HAP for which appropriate acute inhalation dose-response
values are available, the EPA also assesses the potential health risks
due to acute exposure. For these assessments, the EPA makes
conservative assumptions about emission rates, meteorology, and
exposure location. In this proposed rulemaking, as part of the EPA's
efforts to continually improve our methodologies to evaluate the risks
that HAP emitted from categories of industrial sources pose to human
health and the environment,\11\ we are revising our treatment of
meteorological data to use reasonable worst-case air dispersion
conditions in our acute risk screening assessments instead of worst-
case air dispersion conditions. This revised treatment of
meteorological data and the supporting rationale are described in more
detail in Residual Risk Assessment for the Plywood and Composite Wood
Products Source Category in Support of the 2019 Risk and Technology
Review Proposed Rule and in Appendix 5 of the report: Technical Support
Document for Acute Risk Screening Assessment. The EPA will be applying
this revision in RTR rulemakings proposed on or after June 3, 2019.
---------------------------------------------------------------------------

    \11\ See, e.g., U.S. EPA. Screening Methodologies to Support
Risk and Technology Reviews (RTR): A Case Study Analysis (Draft
Report, May 2017. https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html).
---------------------------------------------------------------------------

    To assess the potential acute risk to the maximally exposed
individual, the EPA uses the peak hourly emission rate for each
emission point,\12\ reasonable worst-case air dispersion conditions
(i.e., 99th percentile), and the point of highest off-site exposure.
Specifically, the EPA assumes that peak emissions from the source
category and reasonable worst-case air dispersion conditions co-occur
and that a person is present at the point of maximum exposure.
---------------------------------------------------------------------------

    \12\ In the absence of hourly emission data, the EPA develops
estimates of maximum hourly emission rates by multiplying the
average actual annual emissions rates by a factor (either a
category-specific factor or a default factor of 10) to account for
variability. This is documented in Residual Risk Assessment for the
Plywood and Composite Wood Products Source Category in Support of
the 2019 Risk and Technology Review Proposed Rule and in Appendix 5
of the report: Technical Support Document for Acute Risk Screening
Assessment. Both are available in the docket for this rulemaking.
---------------------------------------------------------------------------

    To characterize the potential health risks associated with
estimated acute inhalation exposures to a HAP, the EPA generally uses
multiple acute dose-response values, including acute RELs, acute
exposure guideline levels (AEGLs), and emergency response planning
guidelines (ERPG) for 1-hour

exposure durations, if available, to calculate acute HQs. The acute HQ
is calculated by dividing the estimated acute exposure concentration by
the acute dose-response value. For each HAP for which acute dose-
response values are available, the EPA calculates acute HQs.
    An acute REL is defined as ``the concentration level at or below
which no adverse health effects are anticipated for a specified
exposure duration.'' \13\ Acute RELs are based on the most sensitive,
relevant, adverse health effect reported in the peer-reviewed medical
and toxicological literature. They are designed to protect the most
sensitive individuals in the population through the inclusion of
margins of safety. Because margins of safety are incorporated to
address data gaps and uncertainties, exceeding the REL does not
automatically indicate an adverse health impact. AEGLs represent
threshold exposure limits for the general public and are applicable to
emergency exposures ranging from 10 minutes to 8 hours.\14\ They are
guideline levels for ``once-in-a-lifetime, short-term exposures to
airborne concentrations of acutely toxic, high-priority chemicals.''
Id. at 21. The AEGL-1 is specifically defined as ``the airborne
concentration (expressed as ppm (parts per million) or mg/m\3\
(milligrams per cubic meter)) of a substance above which it is
predicted that the general population, including susceptible
individuals, could experience notable discomfort, irritation, or
certain asymptomatic nonsensory effects. However, the effects are not
disabling and are transient and reversible upon cessation of
exposure.'' The document also notes that ``Airborne concentrations
below AEGL-1 represent exposure levels that can produce mild and
progressively increasing but transient and nondisabling odor, taste,
and sensory irritation or certain asymptomatic, nonsensory effects.''
Id. AEGL-2 are defined as ``the airborne concentration (expressed as
parts per million or milligrams per cubic meter) of a substance above
which it is predicted that the general population, including
susceptible individuals, could experience irreversible or other
serious, long-lasting adverse health effects or an impaired ability to
escape.'' Id.
---------------------------------------------------------------------------

    \13\ CalEPA issues acute RELs as part of its Air Toxics Hot
Spots Program, and the 1-hour and 8-hour values are documented in
Air Toxics Hot Spots Program Risk Assessment Guidelines, Part I, The
Determination of Acute Reference Exposure Levels for Airborne
Toxicants, which is available at https://oehha.ca.gov/air/general-info/oehha-acute-8-hour-and-chronic-reference-exposure-level-rel-summary.
    \14\ National Academy of Sciences, 2001. Standing Operating
Procedures for Developing Acute Exposure Levels for Hazardous
Chemicals, page 2. Available at https://www.epa.gov/sites/production/files/2015-09/documents/sop_final_standing_operating_procedures_2001.pdf. Note that the
National Advisory Committee for Acute Exposure Guideline Levels for
Hazardous Substances ended in October 2011, but the AEGL program
continues to operate at the EPA and works with the National
Academies to publish final AEGLs (https://www.epa.gov/aegl).
---------------------------------------------------------------------------

    ERPGs are ``developed for emergency planning and are intended as
health-based guideline concentrations for single exposures to
chemicals.'' \15\ Id. at 1. The ERPG-1 is defined as ``the maximum
airborne concentration below which it is believed that nearly all
individuals could be exposed for up to 1 hour without experiencing
other than mild transient adverse health effects or without perceiving
a clearly defined, objectionable odor.'' Id. at 2. Similarly, the ERPG-
2 is defined as ``the maximum airborne concentration below which it is
believed that nearly all individuals could be exposed for up to one
hour without experiencing or developing irreversible or other serious
health effects or symptoms which could impair an individual's ability
to take protective action.'' Id. at 1.
---------------------------------------------------------------------------

    \15\ ERPGS Procedures and Responsibilities. March 2014. American
Industrial Hygiene Association. Available at: https://www.aiha.org/get-involved/AIHAGuidelineFoundation/EmergencyResponsePlanningGuidelines/Documents/ERPG%20Committee%20Standard%20Operating%20Procedures%20%20-%20March%202014%20Revision%20%28Updated%2010-2-2014%29.pdf.
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    An acute REL for 1-hour exposure durations is typically lower than
its corresponding AEGL-1 and ERPG-1. Even though their definitions are
slightly different, AEGL-1s are often the same as the corresponding
ERPG-1s, and AEGL-2s are often equal to ERPG-2s. The maximum HQs from
the EPA's acute inhalation screening risk assessment typically result
when we use the acute REL for a HAP. In cases where the maximum acute
HQ exceeds 1, the EPA also reports the HQ based on the next highest
acute dose-response value (usually the AEGL-1 and/or the ERPG-1).
    For this source category, estimates of short-term (maximum hourly)
emissions were submitted by PCWP ICR respondents. In our review of the
ICR data, the EPA compared the short-term emission estimates to annual
emissions estimates to ensure the short-term emission estimates were
reasonable. The EPA gap-filled short-term emission estimates that were
missing or found to be invalid with short-term emission estimates
calculated using a PCWP emission process-specific acute multiplier. The
acute multiplier, which is a factor multiplied by annual emissions to
estimate maximum hourly emissions, was derived from the ICR data for
each emissions process group. The acute factors used to gap-fill
missing or invalid short-term emission estimates in the PCWP ICR
inventory ranged from 1.2 to 10. Further discussion of the process-
specific factors chosen to fill gaps in the ICR data can be found in
the memorandum, Preparation of Residual Risk Modeling Inputs File for
the PCWP NESHAP, available in the docket for this rulemaking.
    In the EPA's acute inhalation screening risk assessment, acute
impacts are deemed negligible for HAP for which acute HQs are less than
or equal to 1, and no further analysis is performed for these HAP. In
cases where an acute HQ from the screening step is greater than 1, the
EPA assesses the site-specific data to ensure that the acute HQ is at
an off-site location. For this source category, the data refinements
employed consisted of evaluating residential properties outside the
facility boundaries to estimate acute impacts that exceeded an HQ
screen of 1. These refinements are discussed more fully in the Residual
Risk Assessment for the Plywood and Composite Wood Products Source
Category in Support of the 2019 Risk and Technology Review Proposed
Rule, which is available in the docket for this source category.
4. How do we conduct the multipathway exposure and risk screening
assessment?
    The EPA conducts a tiered screening assessment examining the
potential for significant human health risks due to exposures via
routes other than inhalation (i.e., ingestion). We first determine
whether any sources in the source category emit any HAP known to be
persistent and bioaccumulative in the environment, as identified in the
EPA's Air Toxics Risk Assessment Library (See Volume 1, Appendix D, at
https://www.epa.gov/fera/risk-assessment-and-modeling-air-toxics-risk-assessment-reference-library).
    For the PCWP source category, we identified PB-HAP emissions of
arsenic, polychlorinated dibenzodioxins and furans (dioxins/furans),
polycyclic organic matter (POM), cadmium, mercury, and lead, so we
proceeded to the next step of the evaluation. Except for lead, the
human health risk screening assessment for PB-HAP consists of three
progressive tiers. In a Tier 1 screening assessment, we determine
whether the magnitude of the facility-specific emissions of PB-HAP
warrants further evaluation to characterize human health risk through

ingestion exposure. To facilitate this step, we evaluate emissions
against previously developed screening threshold emission rates for
several PB-HAP that are based on a hypothetical upper-end screening
exposure scenario developed for use in conjunction with the EPA's Total
Risk Integrated Methodology.Fate, Transport, and Ecological Exposure
(TRIM.FaTE) model. The PB-HAP with screening threshold emission rates
are arsenic compounds, cadmium compounds, dioxins/furans, mercury
compounds, and POM. Based on the EPA estimates of toxicity and
bioaccumulation potential, these pollutants represent a conservative
list for inclusion in multipathway risk assessments for RTR rules. (See
Volume 1, Appendix D at https://www.epa.gov/sites/production/files/2013-08/documents/volume_1_reflibrary.pdf). In this assessment, we
compare the facility-specific emission rates of these PB-HAP to the
screening threshold emission rates for each PB-HAP to assess the
potential for significant human health risks via the ingestion pathway.
We call this application of the TRIM.FaTE model the Tier 1 screening
assessment. The ratio of a facility's actual emission rate to the Tier
1 screening threshold emission rate is a ``screening value.''
    We derive the Tier 1 screening threshold emission rates for these
PB-HAP (other than lead compounds) to correspond to a maximum excess
lifetime cancer risk of 1-in-1 million (i.e., for arsenic compounds,
dioxins/furans, and POM) or, for HAP that cause noncancer health
effects (i.e., cadmium compounds and mercury compounds), a maximum HQ
of 1. If the emission rate of any one PB-HAP or combination of
carcinogenic PB-HAP in the Tier 1 screening assessment exceeds the Tier
1 screening threshold emission rate for any facility (i.e., the
screening value is greater than 1), we conduct a second screening
assessment, which we call the Tier 2 screening assessment. The Tier 2
screening assessment separates the Tier 1 combined fisher and farmer
exposure scenario into fisher, farmer, and gardener scenarios that
retain upper-bound ingestion rates.
    In the Tier 2 screening assessment, the location of each facility
that exceeds a Tier 1 screening threshold emission rate is used to
refine the assumptions associated with the Tier 1 fisher/farmer
scenarios at that facility. A key assumption in the Tier 1 screening
assessment is that a lake and/or farm is located near the facility. As
part of the Tier 2 screening assessment, we use a U.S. Geological
Survey (USGS) database to identify actual waterbodies within 50 km of
each facility and assume the fisher only consumes fish from lakes
within that 50 km zone. We also examine the differences between local
meteorology near the facility and the meteorology used in the Tier 1
screening assessment. We then adjust the previously-developed Tier 1
screening threshold emission rates for each PB-HAP for each facility
based on an understanding of how exposure concentrations estimated for
the screening scenario change with the use of local meteorology and the
USGS lakes database.
    In the Tier 2 farmer scenario, we maintain an assumption that the
farm is located within 0.5 km of the facility and that the farmer
consumes meat, eggs, dairy, vegetables, and fruit produced near the
facility. We may further refine the Tier 2 screening analysis by
assessing a gardener scenario to characterize a range of exposures,
with the gardener scenario being more plausible in RTR evaluations.
Under the gardener scenario, we assume the gardener consumes home-
produced eggs, vegetables, and fruit products at the same ingestion
rate as the farmer. The Tier 2 screen continues to rely on the high-end
food intake assumptions that were applied in Tier 1 for local fish
(adult female angler at 99th percentile fish consumption \16\) and
locally grown or raised foods (90th percentile consumption of locally
grown or raised foods for the farmer and gardener scenarios \17\). If
PB-HAP emission rates do not result in a Tier 2 screening value greater
than 1, we consider those PB-HAP emissions to pose risks below a level
of concern. If the PB-HAP emission rates for a facility exceed the Tier
2 screening threshold emission rates, we may conduct a Tier 3 screening
assessment.
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    \16\ Burger, J. 2002. Daily consumption of wild fish and game:
Exposures of high end recreationists. International Journal of
Environmental Health Research 12:343-354.
    \17\ U.S. EPA. Exposure Factors Handbook 2011 Edition (Final).
U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/
052F, 2011.
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    There are several analyses that can be included in a Tier 3
screening assessment, depending upon the extent of refinement
warranted, including validating that the lakes are fishable, locating
residential/garden locations for urban and/or rural settings,
considering plume-rise to estimate emissions lost above the mixing
layer, and considering hourly effects of meteorology and plume rise on
chemical fate and transport (a time-series analysis). If necessary, the
EPA may further refine the screening assessment through a site-specific
assessment.
    In evaluating the potential multipathway risk from emissions of
lead compounds, rather than developing a screening threshold emission
rate, we compare maximum estimated chronic inhalation exposure
concentrations to the level of the current National Ambient Air Quality
Standard (NAAQS) for lead.\18\ Values below the level of the primary
(health-based) lead NAAQS are considered to have a low potential for
multipathway risk.
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    \18\ In doing so, the EPA notes that the legal standard for a
primary NAAQS--that a standard is requisite to protect public health
and provide an adequate margin of safety (CAA section 109(b))--
differs from the CAA section 112(f) standard (requiring, among other
things, that the standard provide an ``ample margin of safety to
protect public health''). However, the primary lead NAAQS is a
reasonable measure of determining risk acceptability (i.e., the
first step of the Benzene NESHAP analysis) since it is designed to
protect the most susceptible group in the human population--
children, including children living near major lead emitting
sources. 73 FR 67002/3; 73 FR 67000/3; 73 FR 67005/1. In addition,
applying the level of the primary lead NAAQS at the risk
acceptability step is conservative, since that primary lead NAAQS
reflects an adequate margin of safety.
---------------------------------------------------------------------------

    For further information on the multipathway assessment approach,
see Appendix 6 of the Residual Risk Assessment for the Plywood and
Composite Wood Products Source Category in Support of the 2019 Risk and
Technology Review Proposed Rule, which is available in the docket for
this action.
5. How do we conduct the environmental risk screening assessment?
a. Adverse Environmental Effect, Environmental HAP, and Ecological
Benchmarks
    The EPA conducts a screening assessment to examine the potential
for an adverse environmental effect as required under section
112(f)(2)(A) of the CAA. Section 112(a)(7) of the CAA defines ``adverse
environmental effect'' as ``any significant and widespread adverse
effect, which may reasonably be anticipated, to wildlife, aquatic life,
or other natural resources, including adverse impacts on populations of
endangered or threatened species or significant degradation of
environmental quality over broad areas.''
    The EPA focuses on eight HAP, which are referred to as
``environmental HAP,'' in its screening assessment: Six PB-HAP and two
acid gases. The PB-HAP included in the screening assessment are arsenic
compounds, cadmium compounds, dioxins/furans, POM, mercury (both
inorganic mercury and

methyl mercury), and lead compounds. The acid gases included in the
screening assessment are hydrochloric acid (HCl) and hydrogen fluoride
(HF).
    HAP that persist and bioaccumulate are of particular environmental
concern because they accumulate in the soil, sediment, and water. The
acid gases, HCl and HF, are included due to their well-documented
potential to cause direct damage to terrestrial plants. In the
environmental risk screening assessment, the EPA evaluates the
following four exposure media: Terrestrial soils, surface water bodies
(includes water-column and benthic sediments), fish consumed by
wildlife, and air. Within these four exposure media, the EPA evaluates
nine ecological assessment endpoints, which are defined by the
ecological entity and its attributes. For PB-HAP (other than lead),
both community-level and population-level endpoints are included. For
acid gases, the ecological assessment evaluated is terrestrial plant
communities.
    An ecological benchmark represents a concentration of HAP that has
been linked to a particular environmental effect level. For each
environmental HAP, the EPA identified the available ecological
benchmarks for each assessment endpoint. The EPA identified, where
possible, ecological benchmarks at the following effect levels:
Probable effect levels, lowest-observed-adverse-effect level, and no-
observed-adverse-effect level. In cases where multiple effect levels
were available for a particular PB-HAP and assessment endpoint, the EPA
uses all of the available effect levels to help us to determine whether
ecological risks exist and, if so, whether the risks could be
considered significant and widespread.
    For further information on how the environmental risk screening
assessment was conducted, including a discussion of the risk metrics
used, how the environmental HAP were identified, and how the ecological
benchmarks were selected, see Appendix 9 of the Residual Risk
Assessment for the Plywood and Composite Wood Products Source Category
in Support of the 2019 Risk and Technology Review Proposed Rule, which
is available in the docket for this action.
b. Environmental Risk Screening Methodology
    For the environmental risk screening assessment, the EPA first
determined whether any facilities in the PCWP source category emitted
any of the environmental HAP. For the PCWP source category, the EPA
identified emissions of arsenic compounds, cadmium compounds, dioxins/
furans, lead compounds, mercury compounds, POM, HCl, and HF. Because
the above environmental HAP are emitted by at least one facility in the
source category, we proceeded to the second step of the evaluation.
c. PB-HAP Methodology
    The environmental screening assessment includes six PB-HAP, arsenic
compounds, cadmium compounds, dioxins/furans, POM, mercury (both
inorganic mercury and methyl mercury), and lead compounds. With the
exception of lead, the environmental risk screening assessment for PB-
HAP consists of three tiers. The first tier of the environmental risk
screening assessment uses the same health-protective conceptual model
that is used for the Tier 1 human health screening assessment.
TRIM.FaTE model simulations were used to back-calculate Tier 1
screening threshold emission rates. The screening threshold emission
rates represent the emission rate in tons of pollutant per year that
results in media concentrations at the facility that equal the relevant
ecological benchmark. To assess emissions from each facility in the
category, the reported emission rate for each PB-HAP was compared to
the Tier 1 screening threshold emission rate for that PB-HAP for each
assessment endpoint and effect level. If emissions from a facility do
not exceed the Tier 1 screening threshold emission rate, the facility
``passes'' the screening assessment, and, therefore, is not evaluated
further under the screening approach. If emissions from a facility
exceed the Tier 1 screening threshold emission rate, the EPA evaluates
the facility further in Tier 2.
    In Tier 2 of the environmental screening assessment, the screening
threshold emission rates are adjusted to account for local meteorology
and the actual location of lakes in the vicinity of facilities that did
not pass the Tier 1 screening assessment. For soils, the EPA evaluates
the average soil concentration for all soil parcels within a 7.5-km
radius for each facility and PB-HAP. For the water, sediment, and fish
tissue concentrations, the highest value for each facility for each
pollutant is used. If emission concentrations from a facility do not
exceed the Tier 2 screening threshold emission rate, the facility
``passes'' the screening assessment and typically is not evaluated
further. If emissions from a facility exceed the Tier 2 screening
threshold emission rate, the EPA evaluates the facility further in Tier
3.
    As in the multipathway human health risk assessment, in Tier 3 of
the environmental screening assessment, the EPA examines the
suitability of the lakes around the facilities to support life and
remove those that are not suitable (e.g., lakes that have been filled
in or are industrial ponds), adjust emissions for plume-rise, and
conduct hour-by-hour time-series assessments. If these Tier 3
adjustments to the screening threshold emission rates still indicate
the potential for an adverse environmental effect (i.e., facility
emission rate exceeds the screening threshold emission rate), the EPA
may elect to conduct a more refined assessment using more site-specific
information. If, after additional refinement, the facility emission
rate still exceeds the screening threshold emission rate, the facility
may have the potential to cause an adverse environmental effect.
    To evaluate the potential for an adverse environmental effect from
lead, the EPA compared the average modeled air concentrations (from
HEM-3) of lead around each facility in the source category to the level
of the secondary NAAQS for lead. The secondary lead NAAQS is a
reasonable means of evaluating environmental risk because it is set to
provide substantial protection against adverse welfare effects which
can include ``effects on soils, water, crops, vegetation, man-made
materials, animals, wildlife, weather, visibility and climate, damage
to and deterioration of property, and hazards to transportation, as
well as effects on economic values and on personal comfort and well-
being.''
d. Acid Gas Environmental Risk Methodology
    The environmental screening assessment for acid gases evaluates the
potential phytotoxicity and reduced productivity of plants due to
chronic exposure to HF and HCl. The environmental risk screening
methodology for acid gases is a single-tier screening assessment that
compares modeled ambient air concentrations (from AERMOD) to the
ecological benchmarks for each acid gas. To identify a potential
adverse environmental effect (as defined in section 112(a)(7) of the
CAA) from emissions of HF and HCl, the EPA evaluates the following
metrics: The size of the modeled area around each facility that exceeds
the ecological benchmark for each acid gas, in acres and km\2\; the
percentage of the modeled area around each facility that exceeds the
ecological benchmark for each acid gas; and the area-weighted average
screening value around each facility

(calculated by dividing the area-weighted average concentration over
the 50-km modeling domain by the ecological benchmark for each acid
gas). For further information on the environmental screening assessment
approach, see Appendix 9 of the Residual Risk Assessment for the
Plywood and Composite Wood Products Source Category in Support of the
2019 Risk and Technology Review Proposed Rule, which is available in
the docket for this action.
6. How do we conduct facility-wide assessments?
    To put the source category risks in context, the EPA typically
examines the risks from the entire ``facility,'' where the facility
includes all HAP-emitting operations within a contiguous area and under
common control. In other words, the EPA examines the HAP emissions not
only from the source category emission points of interest, but also
emissions of HAP from all other emission sources at the facility for
which the EPA has data. For this source category, the EPA conducted the
facility-wide assessment using a dataset compiled from the 2014 NEI.
The source category records of that NEI dataset were removed and
replaced with the quality-assured ICR source category dataset described
in the memorandum titled Preparation of the Residual Risk Modeling
Input File for the PCWP NESHAP, in the docket for this rulemaking. This
ICR source category dataset was then combined with the non-source
category records from the NEI for that facility. The combined facility-
wide file was then used to analyze risks due to the inhalation of HAP
that are emitted ``facility-wide'' for the populations residing within
50 km of each facility, consistent with the methods used for the source
category analysis described above. For these facility-wide risk
analyses, the modeled source category risks were compared to the
facility-wide risks to determine the portion of the facility-wide risks
that could be attributed to the source category addressed in this
proposal. The EPA also specifically examined the facility that was
associated with the highest estimate of risk and determined the
percentage of that risk attributable to the source category of
interest. The Residual Risk Assessment for the Plywood and Composite
Wood Products Source Category in Support of the 2019 Risk and
Technology Review Proposed Rule, available through the docket for this
action, provides the methodology and results of the facility-wide
analyses, including all facility-wide risks and the percentage of
source category contribution to facility-wide risks.
7. How do we consider uncertainties in risk assessment?
    Uncertainty and the potential for bias are inherent in all risk
assessments, including those performed for this proposal. Although
uncertainty exists, we believe that our approach, which used
conservative tools and assumptions, ensures that our decisions are
health and environmentally protective. A brief discussion of the
uncertainties in the RTR emissions dataset, dispersion modeling,
inhalation exposure estimates, and dose-response relationships follows
below. Also included are those uncertainties specific to acute
screening assessments, multipathway screening assessments, and our
environmental risk screening assessments. A more thorough discussion of
these uncertainties is included in the Residual Risk Assessment for the
Plywood and Composite Wood Products Source Category in Support of the
2019 Risk and Technology Review Proposed Rule, which is available in
the docket for this action. If a multipathway site-specific assessment
was performed for this source category, a full discussion of the
uncertainties associated with that assessment can be found in Appendix
11 of that document, Site-Specific Human Health Multipathway Residual
Risk Assessment Report.
a. Uncertainties in the RTR Emissions Dataset
    Although the development of the RTR emissions dataset involved
quality assurance/quality control processes, the accuracy of emissions
values will vary depending on the source of the data, the degree to
which data are incomplete or missing, the degree to which assumptions
made to complete the datasets are accurate, errors in emission
estimates, and other factors. For example, older emission factors that
do not account for relatively recent reductions in resin formaldehyde
content may have been used by some PCWP mills to estimate emissions
from uncontrolled process units that are hard to test, resulting in
overestimation of formaldehyde emissions. The emission estimates
considered in this analysis generally are annual totals for certain
years, and they do not reflect short-term fluctuations during the
course of a year or variations from year to year. For facilities with
missing or invalid short-term emission estimates in their PCWP ICR
data, the estimates of maximum hourly emission rates for the acute
effects screening assessment were based on an emission adjustment
factor applied to the average annual hourly emission rates, which are
intended to account for emission fluctuations due to normal facility
operations.
b. Uncertainties in Dispersion Modeling
    The EPA recognizes there is uncertainty in ambient concentration
estimates associated with any model, including the EPA's recommended
regulatory dispersion model, AERMOD. In using a model to estimate
ambient pollutant concentrations, the user chooses certain options to
apply. For RTR assessments, the EPA selects some model options that
have the potential to overestimate ambient air concentrations (e.g.,
not including plume depletion or pollutant transformation). The EPA
selects other model options that have the potential to underestimate
ambient impacts (e.g., not including building downwash). Other options
that the EPA selects have the potential to either under- or
overestimate ambient levels (e.g., meteorology and receptor locations).
On balance, considering the directional nature of the uncertainties
commonly present in ambient concentrations estimated by dispersion
models, the approach the EPA applies in the RTR assessments should
yield unbiased estimates of ambient HAP concentrations. After reviewing
the physical characteristics of emission releases from batch and
continuous lumber kilns, dispersion and risk modelers at the EPA
recommend the buoyant plume rise resulting from the elevated
temperature of kiln exhaust be taken into account when modeling kiln
fugitive emissions to improve accuracy. Appendix 12 of the document,
Residual Risk Assessment for the Plywood and Composite Wood Products
Source Category in Support of the 2019 Risk and Technology Review
Proposed Rule, in the docket for this rulemaking describes the
methodology and results. We also note that the selection of meteorology
dataset location could have an impact on the risk estimates. As the EPA
continues to update and expand the library of meteorological station
data used in our risk assessments, we expect to reduce this
variability.
c. Uncertainties in Inhalation Exposure Assessment
    Although every effort is made to identify all of the relevant
facilities and emission points, as well as to develop accurate
estimates of the annual emission rates for all relevant HAP, the
uncertainties in the EPA's emission inventory likely dominate the
uncertainties in the exposure assessment. Some uncertainties in our

exposure assessment include human mobility, using the centroid of each
census block, assuming lifetime exposure, and assuming only outdoor
exposures. For most of these factors, there is neither an under nor
overestimate when looking at the maximum individual risk or the
incidence, but the shape of the distribution of risks may be affected.
With respect to outdoor exposures, actual exposures may not be as high
if people spend time indoors, especially for very reactive pollutants
or larger particles. For all factors, the EPA reduces uncertainty when
possible. For example, with respect to census-block centroids, the EPA
analyzes large blocks using aerial imagery and adjust locations of the
block centroids to better represent the population in the blocks. The
EPA also adds additional receptor locations where the population of a
block is not well represented by a single location.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in the EPA's risk assessments for cancer effects
from chronic exposures and noncancer effects from both chronic and
acute exposures. Some uncertainties are generally expressed
quantitatively, and others are generally expressed in qualitative
terms. We note, as a preface to this discussion, a point on dose-
response uncertainty that is stated in the EPA's 2005 Guidelines for
Carcinogen Risk Assessment; namely, that ``the primary goal of EPA
actions is protection of human health; accordingly, as an Agency
policy, risk assessment procedures, including default options that are
used in the absence of scientific data to the contrary, should be
health protective'' (the EPA's 2005 Guidelines for Carcinogen Risk
Assessment, page 1-7). This is the approach followed here as summarized
in the next paragraphs.
    Cancer UREs used in the EPA's risk assessments are those that have
been developed to generally provide an upper bound estimate of
risk.\19\ That is, they represent a ``plausible upper limit to the true
value of a quantity'' (although this is usually not a true statistical
confidence limit). In some circumstances, the true risk could be as low
as zero; however, in other circumstances the risk could be greater.\20\
Chronic noncancer RfC and reference dose (RfD) values represent chronic
exposure levels that are intended to be health-protective levels. To
derive dose-response values that are intended to be ``without
appreciable risk,'' the methodology relies upon an uncertainty factor
(UF) approach,\21\ which considers uncertainty, variability, and gaps
in the available data. The UFs are applied to derive dose-response
values that are intended to protect against appreciable risk of
deleterious effects.
---------------------------------------------------------------------------

    \19\ IRIS glossary (https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&glossaryName=IRIS%20Glossary).
    \20\ An exception to this is the URE for benzene, which is
considered to cover a range of values, each end of which is
considered to be equally plausible, and which is based on maximum
likelihood estimates.
    \21\ See A Review of the Reference Dose and Reference
Concentration Processes, U.S. EPA, December 2002, and Methods for
Derivation of Inhalation Reference Concentrations and Application of
Inhalation Dosimetry, U.S. EPA, 1994.
---------------------------------------------------------------------------

    Many of the UFs used to account for variability and uncertainty in
the development of acute dose-response values are quite similar to
those developed for chronic durations. Additional adjustments are often
applied to account for uncertainty in extrapolation from observations
at one exposure duration (e.g., 4 hours) to derive an acute dose-
response value at another exposure duration (e.g., 1 hour). Not all
acute dose-response values are developed for the same purpose, and care
must be taken when interpreting the results of an acute assessment of
human health effects relative to the dose-response value or values
being exceeded. Where relevant to the estimated exposures, the lack of
acute dose-response values at different levels of severity should be
factored into the risk characterization as potential uncertainties.
    Uncertainty also exists in the selection of ecological benchmarks
for the environmental risk screening assessment. The EPA established a
hierarchy of preferred benchmark sources to allow selection of
benchmarks for each environmental HAP at each ecological assessment
endpoint. We searched for benchmarks for three effect levels (i.e., no-
effects level, threshold-effect level, and probable effect level), but
not all combinations of ecological assessment/environmental HAP had
benchmarks for all three effect levels. Where multiple effect levels
were available for a particular HAP and assessment endpoint, we used
all of the available effect levels to help us determine whether risk
exists and whether the risk could be considered significant and
widespread.
    Although the EPA makes every effort to identify appropriate human
health effect dose-response values for all pollutants emitted by the
sources in this risk assessment, some HAP emitted by this source
category are lacking dose-response assessments. Accordingly, these
pollutants cannot be included in the quantitative risk assessment,
which could result in quantitative estimates understating HAP risk. To
help to alleviate this potential underestimate, where the EPA concludes
similarity with a HAP for which a dose-response value is available, we
use that value as a surrogate for the assessment of the HAP for which
no value is available. To the extent use of surrogates indicates
appreciable risk, the EPA may identify a need to increase priority for
an IRIS assessment for that substance. We additionally note that,
generally speaking, HAP of greatest concern due to environmental
exposures and hazard are those for which dose-response assessments have
been performed, reducing the likelihood of understating risk. Further,
HAP not included in the quantitative assessment are assessed
qualitatively and considered in the risk characterization that informs
the risk management decisions, including consideration of HAP
reductions achieved by various control options.
    For a group of compounds that are unspeciated (e.g., glycol
ethers), the EPA conservatively uses the most protective dose-response
value of an individual compound in that group to estimate risk.
Similarly, for an individual compound in a group (e.g., ethylene glycol
diethyl ether) that does not have a specified dose-response value, the
EPA also applies the most protective dose-response value from the other
compounds in the group to estimate risk.
e. Uncertainties in Acute Inhalation Screening Assessments
    In addition to the uncertainties highlighted above, there are
several factors specific to the acute exposure assessment that the EPA
conducts as part of the risk review under section 112 of the CAA. The
accuracy of an acute inhalation exposure assessment depends on the
simultaneous occurrence of independent factors that may vary greatly,
such as hourly emission rates, meteorology, and the presence of a
person. In the acute screening assessment that the EPA conducts under
the RTR program, we assume that peak emissions from the source category
and reasonable worst-case air dispersion conditions (i.e., 99th
percentile) co-occur. The EPA then includes the additional assumption
that

a person is located at this point at the same time. Together, these
assumptions represent a reasonable worst-case exposure scenario. In
most cases, it is unlikely that a person would be located at the point
of maximum exposure during the time when peak emissions and reasonable
worst-case air dispersion conditions occur simultaneously.
f. Uncertainties in the Multipathway and Environmental Risk Screening
Assessments
    For each source category, the EPA generally relies on site-specific
levels of PB-HAP or environmental HAP emissions to determine whether a
refined assessment of the impacts from multipathway exposures is
necessary or whether it is necessary to perform an environmental
screening assessment. This determination is based on the results of a
three-tiered screening assessment that relies on the outputs from
models--TRIM.FaTE and AERMOD--that estimate environmental pollutant
concentrations and human exposures for five PB-HAP (dioxins, POM,
mercury, cadmium, and arsenic) and two acid gases (HF and HCl). For
lead, the EPA uses AERMOD to determine ambient air concentrations,
which are then compared to the secondary NAAQS standard for lead. Two
important types of uncertainty associated with the use of these models
in RTR risk assessments and inherent to any assessment that relies on
environmental modeling are model uncertainty and input uncertainty.\22\
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    \22\ In the context of this discussion, the term ``uncertainty''
as it pertains to exposure and risk encompasses both variability in
the range of expected inputs and screening results due to existing
spatial, temporal, and other factors, as well as uncertainty in
being able to accurately estimate the true result.
---------------------------------------------------------------------------

    Model uncertainty concerns whether the model adequately represents
the actual processes (e.g., movement and accumulation) that might occur
in the environment. For example, does the model adequately describe the
movement of a pollutant through the soil? This type of uncertainty is
difficult to quantify. However, based on feedback received from
previous EPA SAB reviews and other reviews, we are confident that the
models used in the screening assessments are appropriate and state-of-
the-art for the multipathway and environmental screening risk
assessments conducted in support of RTR.
    Input uncertainty is concerned with how accurately the models have
been configured and parameterized for the assessment at hand. For Tier
1 of the multipathway and environmental screening assessments, the EPA
configured the models to avoid underestimating exposure and risk. This
was accomplished by selecting upper-end values from nationally
representative datasets for the more influential parameters in the
environmental model, including selection and spatial configuration of
the area of interest, lake location and size, meteorology, surface
water, soil characteristics, and structure of the aquatic food web. The
EPA also assumes an ingestion exposure scenario and values for human
exposure factors that represent reasonable maximum exposures.
    In Tier 2 of the multipathway and environmental screening
assessments, the EPA refines the model inputs to account for
meteorological patterns in the vicinity of the facility versus using
upper-end national values and identifies the actual location of lakes
near the facility rather than the default lake location applied in Tier
1. By refining the screening approach in Tier 2 to account for local
geographical and meteorological data, the EPA decreases the likelihood
that concentrations in environmental media are overestimated, thereby
increasing the usefulness of the screening assessment. In Tier 3 of the
screening assessments, the EPA refines the model inputs again to
account for hour-by-hour plume rise and the height of the mixing layer.
The EPA can also use those hour-by-hour meteorological data in a
TRIM.FaTE run using the screening configuration corresponding to the
lake location. These refinements produce a more accurate estimate of
chemical concentrations in the media of interest, thereby reducing the
uncertainty with those estimates. The assumptions and the associated
uncertainties regarding the selected ingestion exposure scenario are
the same for all three tiers.
    For the environmental screening assessment for acid gases, the EPA
employs a single-tiered approach. The EPA uses the modeled air
concentrations and compare those with ecological benchmarks.
    For all tiers of the multipathway and environmental screening
assessments, the EPA's approach to addressing model input uncertainty
is generally cautious. The EPA chooses model inputs from the upper end
of the range of possible values for the influential parameters used in
the models, and assumes that the exposed individual exhibits ingestion
behavior that would lead to a high total exposure. This approach
reduces the likelihood of not identifying high risks for adverse
impacts.
    Despite the uncertainties, when individual pollutants or facilities
do not exceed screening threshold emission rates (i.e., screen out),
the EPA is confident that the potential for adverse multipathway
impacts on human health is very low. On the other hand, when individual
pollutants or facilities do exceed screening threshold emission rates,
it does not mean that impacts are significant, only that the EPA cannot
rule out that possibility and that a refined assessment for the site
might be necessary to obtain a more accurate risk characterization for
the source category.
    The EPA evaluates the following HAP in the multipathway and/or
environmental risk screening assessments, where applicable: Arsenic,
cadmium, dioxins/furans, lead, mercury (both inorganic and methyl
mercury), POM, HCl, and HF. These HAP represent pollutants that can
cause adverse impacts either through direct exposure to HAP in the air
or through exposure to HAP that are deposited from the air onto soils
and surface waters and then through the environment into the food web.
These HAP represent those HAP for which the EPA can conduct a
meaningful multipathway or environmental screening risk assessment. For
other HAP not included in our screening assessments, the model has not
been parameterized such that it can be used for that purpose. In some
cases, depending on the HAP, the EPA may not have appropriate
multipathway models that allow us to predict the concentration of that
pollutant. The EPA acknowledges that other HAP beyond these that we are
evaluating may have the potential to cause adverse effects and,
therefore, the EPA may evaluate other relevant HAP in the future, as
modeling science and resources allow.

IV. Analytical Results and Proposed Decisions

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

1. Chronic Inhalation Risk Assessment Results
    Table 2 of this preamble provides an overall summary of the
inhalation risk results. The results of the chronic baseline inhalation
cancer risk assessment indicate that, based on estimates of current
actual and allowable emissions, the MIR posed by the PCWP source
category was estimated to be 30-in-1 million. The risk driver is
chiefly formaldehyde emissions from batch and continuous lumber kilns.
The total estimated cancer incidence based on actual and allowable
emission levels from all PCWP emission

sources is 0.03 excess cancer cases per year, or one case in every 33
years, with emissions from the lumber kilns representing 43 percent of
the modeled cancer incidence in the source category. Emissions of
formaldehyde, acetaldehyde, and chromium VI compounds contributed 93
percent to this cancer incidence with formaldehyde being the largest
contributor (76 percent of the incidence). Based upon actual emissions
from the source category, approximately 200,000 people were exposed to
cancer risks above or equal to 1-in-1 million.
    The maximum chronic noncancer HI (TOSHI) values based on actual and
allowable emissions for the source category were estimated to be less
than 1. Based upon actual emissions from the source category,
respiratory risks were driven by acrolein, acetaldehyde, and
formaldehyde emissions from batch lumber kilns. Based upon allowable
emissions from the source category, the respiratory risk was driven by
methylene diphenyl diisocyanate emissions from a miscellaneous coating
operation and formaldehyde emissions from lumber kilns.

                                   Table 2--Plywood and Composite Wood Products Inhalation Risk Assessment Results \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                              Estimated
                                                            Maximum         population at     Estimated annual   Maximum chronic     Maximum screening
          Risk assessment               Number of      individual cancer  increased risk of   cancer incidence   noncancer TOSHI     acute noncancer HQ
                                      facilities \2\       risk (in 1      cancer >=1-in-1    (cases per year)         \4\                  \5\
                                                          million) \3\         million
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Baseline Actual Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Category...................                233                 30            204,000               0.03                0.8  4 (REL) 0.2 (AEGL-1).
Facility-Wide.....................                233                 30            260,000               0.04                  1
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Baseline Allowable Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Category...................                233                 30            230,000               0.03                0.8
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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 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 HQ values. HQ values
  shown use the lowest available acute threshold value, which in most cases is the REL. When an HQ exceeds 1, the EPA also shows the HQ using the next
  lowest available acute dose-response value.

2. Screening Level Acute Risk Assessment Results
    Worst-case acute HQs were calculated for every HAP for which there
is an acute health benchmark using actual emissions. The maximum
refined off-site acute noncancer HQ values for the source category were
equal to 4 from acrolein emissions and 2 from formaldehyde emissions
(based on the acute (1-hr) REL for these pollutants). The acrolein and
formaldehyde maximum HQ values were at separate facilities. No other
acute health benchmarks were exceeded for this source category. The
acute risk driver for acrolein was primarily from continuous lumber
kilns and the MIR location for acute formaldehyde risks were from batch
lumber kilns. The continuous and batch lumber kilns were modeled with
hourly emissions ranging from 2 to 8 times the annual average hourly
emissions rate. Acute HQs are not calculated for allowable or whole
facility emissions.
3. Multipathway Risk Screening Results
    Results of the worst-case Tier 1 screening analysis indicate that
PB-HAP emissions (based on estimates of actual emissions) emitted from
the source category exceeded the screening values for the carcinogenic
PB-HAP (arsenic, dioxin/furan, and POM compounds) and for the
noncarcinogenic PB-HAP (cadmium and mercury) based upon emissions from
48 facilities reporting carcinogenic PB-HAP and 19 facilities reporting
non-carcinogenic PB-HAP in the source category. For the PB-HAP and
facilities that did not screen out at Tier 1, the EPA conducted a Tier
2 screening analysis.
    The Tier 2 screen replaces some of the assumptions used in Tier 1
with site-specific data, the location of fishable lakes, and local wind
direction and speed. The Tier 2 screen continues to rely on high-end
assumptions about consumption of local fish and locally grown or raised
foods (adult female angler at 99th percentile consumption for fish \23\
for the fisher scenario and 90th percentile for consumption of locally
raised livestock and grown produce (vegetables and fruits) \24\) for
the farmer scenario and uses an assumption that the same individual
consumes each of these foods in high end quantities (i.e., that an
individual has high end ingestion rates for each food). The result of
this analysis was the development of site-specific concentrations of
dioxin/furan, POM compounds, arsenic compounds, cadmium and mercury
compounds. It is important to note that, even with the inclusion of
some site-specific information in the Tier 2 analysis, the multipathway
screening analysis is a still a very conservative, health-protective
assessment (e.g., upper-bound consumption of local fish, locally grown,
and/or raised foods) and in all likelihood will yield results that
serve as an upper-bound multipathway risk associated with a facility.
---------------------------------------------------------------------------

    \23\ Burger, J. 2002. Daily consumption of wild fish and game:
Exposures of high end recreationists. International Journal of
Environmental Health Research 12:343-354.
    \24\ U.S. EPA. Exposure Factors Handbook 2011 Edition (Final).
U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/
052F, 2011.
---------------------------------------------------------------------------

    Based on this upper-bound Tier 2 screening assessment for
carcinogens, the dioxin/furan and POM emission rates for all facilities
and scenarios were below levels of concern. Arsenic emissions exceeded
the screening value by a factor of 70 for the farmer scenario, a factor
of 40 for the gardener scenario, and a factor of 6 for the fisher
scenario. The Tier 2 gardener scenario is based upon the same ingestion
rate of produce as the farmer for a rural environment. No additional
refined screens or site-specific assessments were conducted for

emissions of arsenic based upon the conservative nature of the Tier 2
screen and because the screening value was below the level of
acceptability of 100-in-1 million. For the non-carcinogens, emissions
of cadmium were below an HQ of 1 for the Tier 2 fisher scenario. For
mercury, three facilities exceeded the Tier 2 multipathway screening
values of 1 by a factor of 2 based upon aggregate lake impacts by
facilities within the source category for the fisher scenario.
    For mercury, the EPA conducted a Tier 3 multipathway screen for two
facilities which included two of the three individual stages. These
stages included a lake assessment for fishability and the mass lost due
to plume rise, a time-series assessment was not conducted. A lake and
plume rise assessment was conducted resulting in a maximum Tier 3
screening value of 2, a 20-percent reduction in their Tier 2 screening
value was achieved due to plume rise. A screening value in any of the
tiers is not an estimate of the cancer risk or a noncancer HQ (or HI).
Rather, a screening value represents a high-end estimate of what the
risk or hazard may be. For example, facility emissions resulting in a
screening value of 2 for a non-carcinogen can be interpreted to mean
that we are confident that the HQ would be lower than 2. Similarly,
facility emissions resulting in a cancer screening value of 40 for a
carcinogen means that we are confident that the cancer risk is lower
than 40-in-1 million. Our confidence comes from the health-protective
assumptions that are incorporated into the screens: We choose inputs
from the upper end of the range of possible values for the influential
parameters used in the screens; and we assume food consumption
behaviors that would lead to high total exposure. This risk assessment
estimates the maximum hazard for mercury through fish consumption based
on upper bound screens and the maximum excess cancer risks from
dioxins/furans and arsenic through ingestion of fish and farm produce.
    When we progress from the model designs of the Tier 1, 2, and 3
screens to a site-specific assessment, we refine the risk assessment
through incorporation of additional site-specific data and enhanced
model designs. Site-specific refinements include the following; (1)
improved spatial locations identifying the boundaries of the watershed
and lakes within the watershed as it relates to surrounding facilities
within the source category; (2) calculating actual soil/water run-off
amounts to target lakes based upon actual soil type(s) and elevation
changes associated with the affected watershed versus assuming a worst-
case assumption of 100-percent run-off to target lakes; and (3)
incorporating AERMOD deposition of pollutants into TRIM.FaTE to
accurately account for site-specific release parameters such as stack
heights and exit gas temperatures, versus using TRIMFaTE's simple
dispersion algorithms that assume the pollutant is uniformly
distributed within the airshed. These refinements have the net effect
of improved modeling of the mass of HAP entering a lake by more
accurately defining the watershed/lake boundaries as well as the
dispersion of HAP into the atmosphere to better reflect deposition
contours across all target watersheds and lakes in our 50 km model
domain.
    The maximum mercury Tier 2 noncancer screening value for this
source category is 2 with subsequent refinement resulting in a Tier 3
screening value of 2. No additional refinements to the Tier 3 screen
value of 2 were conducted by the EPA. Risk results from four site-
specific mercury assessments the EPA has conducted for four RTR source
categories resulted in noncancer HQs that range from 50 to 800 times
lower than the respective Tier 2 screening value for these facilities
(refer to EPA Docket ID: EPA-HQ-OAR-2016-0243 for a copy of these
reports).\25\ Based on our review of these analyses, we would expect at
least a one order of magnitude decrease in all Tier 2 noncancer
screening values for mercury for the PCWP source category, if we were
to perform a site-specific assessment. In addition, based upon the
conservative nature of the screens and the level of additional
refinements that would go into a site-specific multipathway assessment,
were one to be conducted, we are confident that the HI for ingestion
exposure, specifically mercury through fish ingestion, is less than 1.
---------------------------------------------------------------------------

    \25\ EPA Docket records: Appendix 11 of the Residual Risk
Assessment for the Taconite Manufacturing Source Category in Support
of the Risk and Technology Review 2019 Proposed Rule; Appendix 11 of
the Residual Risk Assessment for the Integrated Iron and Steel
Source Category in Support of the Risk and Technology Review 2019
Proposed Rule; Appendix 11 of the Residual Risk Assessment for the
Portland Cement Manufacturing Source Category in Support of the 2018
Risk and Technology Review Final Rule; and Appendix 11 of the
Residual Risk Assessment for the Coal and Oil-Fired EGU Source
Category in Support of the 2018 Risk and Technology Review Proposed
Rule.
---------------------------------------------------------------------------

    Further details on the Tier 3 screening assessment can be found in
Appendix 11 of Residual Risk Assessment for the Plywood Composite and
Wood Products Source Category in Support of the 2019 Risk and
Technology Review Proposed Rule, in the docket for this action.
    In evaluating the potential for multipathway effects from emissions
of lead, the EPA compared modeled annual lead concentrations to the
primary NAAQS level for lead (0.15 [mu]g/m\3\, arithmetic mean
concentration over a 3-month period. The highest annual average lead
concentration of 0.013 [micro]g/m\3\ is below the NAAQS level for lead,
indicating a low potential for multipathway impacts.
4. Environmental Risk Screening Results
    The EPA conducted an environmental risk screening assessment for
the PCWP source category for the following pollutants: Arsenic,
cadmium, dioxins/furans, HCl, HF, lead, mercury (methyl mercury and
mercuric chloride), and POM.
    In the Tier 1 screening analysis for PB-HAP (other than lead, which
was evaluated differently), arsenic, cadmium, dioxins/furans, and POM
emissions had no Tier 1 exceedances for any ecological benchmark.
Divalent mercury emissions at nine facilities had Tier 1 exceedances
for the surface soil threshold levels (invertebrate and plant
communities) by a maximum screening value of 5. Methyl mercury
emissions at 13 facilities had Tier 1 exceedances for the surface soil
NOAEL (avian ground insectivores) by a maximum screening value of 7.
    A Tier 2 screening assessment was performed for divalent mercury
and methyl mercury. Divalent mercury and methyl mercury had no Tier 2
exceedances for any ecological benchmark. For lead, the EPA did not
estimate any exceedances of the secondary lead NAAQS. For HCl and HF,
the average modeled concentration around each facility (i.e., the
average concentration of all off-site data points in the modeling
domain) did not exceed any ecological benchmark. In addition, each
individual modeled concentration of HCl and HF (i.e., each off-site
data point in the modeling domain) was below the ecological benchmarks
for all facilities. Based on the results of the environmental risk
screening analysis, the EPA does not expect an adverse environmental
effect as a result of HAP emissions from this source category.
5. Facility-Wide Risk Results
    Results of the assessment of facility-wide emissions indicate that
of the 233 facilities, 182 facilities have a facility-wide MIR cancer
risk greater than 1-in-1 million. The maximum facility-wide cancer risk
is 30-in-1 million, mainly driven by formaldehyde emissions from batch
and continuous lumber kilns. The

total estimated cancer incidence from the whole facility is 0.04 excess
cancer cases per year, or one case in every 25 years. Approximately
260,000 people are estimated to have cancer risks greater than 1-in-1
million. The maximum facility-wide chronic noncancer TOSHI is estimated
to be equal to 1, driven by emissions of acrolein, chlorine, and HCl
from non-category sources.
6. What demographic groups might benefit from this regulation?
    To examine the potential for any environmental justice issues that
might be associated with the source category, the EPA performed a
demographic analysis, which is an assessment of risk to individual
demographic groups of the populations living within 5 km and within 50
km of the facilities. In the analysis, the EPA evaluated the
distribution of HAP-related cancer and noncancer risk from the PCWP
source category across different demographic groups within the
populations living near facilities.
    The results of the demographic analysis are summarized in Table 3
below. These results, for various demographic groups, are based on the
estimated risk from actual emissions levels for the population living
within 50 km of the facilities.

                 Table 3--Plywood and Composite Wood Products Demographic Risk Analysis Results
----------------------------------------------------------------------------------------------------------------
                                                                             Population with
                                                                            cancer risk at or   Population with
                                                             Nationwide        above 1-in-1      chronic hazard
                                                                              million due to   index above 1 due
                                                                                PCWP             to PCWP
----------------------------------------------------------------------------------------------------------------
Total Population.......................................        317,746,049            204,164                  0
----------------------------------------------------------------------------------------------------------------
                                                 Race by Percent
----------------------------------------------------------------------------------------------------------------
White..................................................                 62                 63                  0
All Other Races........................................                 38                 37                  0
----------------------------------------------------------------------------------------------------------------
                                                 Race by Percent
----------------------------------------------------------------------------------------------------------------
Hispanic or Latino (includes white and nonwhite).......                 18                  9                  0
African American.......................................                 12                 24                  0
Native American........................................                0.8                1.1                  0
Other and Multiracial..................................                  7                  3                  0
----------------------------------------------------------------------------------------------------------------
                                                Income by Percent
----------------------------------------------------------------------------------------------------------------
Below Poverty Level....................................                 14                 23                  0