[Federal Register Volume 88, Number 96 (Thursday, May 18, 2023)]
[Proposed Rules]
[Pages 31856-31887]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-10067]



[[Page 31855]]

Vol. 88

Thursday,

No. 96

May 18, 2023

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; Proposed Rule

  Federal Register / Vol. 88, No. 96 / Thursday, May 18, 2023 / 
Proposed Rules  

[[Page 31856]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2016-0243; FRL-5185.1-01-OAR]
RIN 2060-AV56


National Emission Standards for Hazardous Air Pollutants: Plywood 
and Composite Wood Products

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 Emission Standards for Hazardous Air 
Pollutants (NESHAP) for Plywood and Composite Wood Products (PCWP), as 
required by the Clean Air Act (CAA). To ensure that all emissions of 
hazardous air pollutants (HAP) from sources in the source category are 
regulated, the EPA is proposing HAP standards for processes currently 
unregulated for total HAP (including acetaldehyde, acrolein, 
formaldehyde, methanol, phenol, propionaldehyde), non-mercury (non-Hg) 
HAP metals, mercury (Hg), hydrogen chloride (HCl), polycyclic aromatic 
hydrocarbons (PAH), dioxin/furan (D/F), and methylene diphenyl 
diisocyanate (MDI). The standards the EPA is proposing include emission 
limitations and work practices applicable for PCWP process units and 
lumber kilns located at facilities that are major sources of HAP 
emissions. This proposal responds to the 2007 partial remand and 
vacatur of portions of the 2004 PCWP NESHAP in which the EPA previously 
concluded maximum achievable control technology was represented by no 
control (i.e., no emissions reduction). This proposal also responds to 
or requests comment on issues raised in a petition for reconsideration 
the EPA received regarding the technology review and other amendments 
to the PCWP NESHAP the EPA finalized on August 13, 2020.

DATES: Comments must be received on or before July 3, 2023. 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 June 20, 2023.
    Public hearing: If anyone contacts us requesting a public hearing 
on or before May 23, 2023, we will hold a virtual public hearing. 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 protected]. Include Docket ID No. EPA-
HQ-OAR-2016-0243 in the subject line of the message.
     Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2016-0243.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OAR-0216-0243, 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: (919) 541-2159; and email address: 
[email protected].

SUPPLEMENTARY INFORMATION:
    Participation in virtual public hearing. To request a virtual 
public hearing, contact the public hearing team at (888) 372-8699 or by 
email at [email protected]. If requested, the hearing will be 
held via virtual platform on June 2, 2023. The hearing will convene at 
10:00 a.m. Eastern Time (ET) and will conclude at 4:00 p.m. ET. The EPA 
may close a session 15 minutes after the last pre-registered speaker 
has testified if there are no additional speakers. The EPA will 
announce further details at https://www.epa.gov/stationary-sources-air-pollution/plywood-and-composite-wood-products-manufacture-national-emission.
    If a public hearing is requested, the EPA will begin pre-
registering speakers for the hearing no later than 1 business day after 
a request has been received. To register to speak at the virtual 
hearing, please use the online registration form available at https://www.epa.gov/stationary-sources-air-pollution/plywood-and-composite-wood-products-manufacture-national-emission or contact the public 
hearing team at (888) 372-8699 or by email at 
[email protected]. The last day to pre-register to speak at the 
hearing will be May 30, 2023. Prior to the hearing, the EPA will post a 
general agenda that will list pre-registered speakers in approximate 
order at: https://www.epa.gov/stationary-sources-air-pollution/plywood-and-composite-wood-products-manufacture-national-emission.
    The EPA will make every effort to follow the schedule as closely as 
possible on the day of the hearing; however, please plan for the 
hearings to run either ahead of schedule or behind schedule.
    Each commenter will have 4 minutes to provide oral testimony. The 
EPA encourages commenters to submit a copy of their oral testimony as 
written comments to the rulemaking docket.
    The EPA may ask clarifying questions during the oral presentations 
but will not respond to the presentations at that time. Written 
statements and supporting information submitted during the comment 
period will be considered with the same weight as oral testimony and 
supporting information presented at the public hearing.
    Please note that any updates made to any aspect of the hearing will 
be posted online at https://www.epa.gov/stationary-sources-air-pollution/plywood-and-composite-wood-products-manufacture-national-emission. While the EPA expects the hearing to go forward as set forth 
above, please monitor our website or contact the public hearing team at 
(888) 372-8699 or by email at [email protected] to determine if 
there are any updates. The EPA does not intend to publish a document in 
the Federal Register announcing updates.
    If you require the services of a translator or special 
accommodation such as audio description, please pre-register for the 
hearing with the public hearing team and describe your needs by May 25, 
2023. The EPA may not be able to arrange accommodations without 
advanced notice.

[[Page 31857]]

    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 https://www.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. With the exception of such material, publicly available docket 
materials are available electronically in Regulations.gov.
    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 electronically to https://www.regulations.gov/ 
any information that you consider to be CBI or other information whose 
disclosure is restricted by statute. This type of information should be 
submitted 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/. 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, note the docket ID, 
mark the outside of the digital storage media as CBI, and 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 and note the docket ID. 
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.
    Our preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol (FTP), 
or other online file sharing services (e.g., Dropbox, OneDrive, Google 
Drive). Electronic submissions must be transmitted directly to the 
Office of Air Quality Planning and Standards (OAQPS) CBI Office at the 
email address [email protected], and as described above, should include 
clear CBI markings and note the docket ID. If assistance is needed with 
submitting large electronic files that exceed the file size limit for 
email attachments, and if you do not have your own file sharing 
service, please email [email protected] to request a file transfer link. 
If sending CBI information through the postal service, please send it 
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. The 
mailed CBI material should be double wrapped and clearly marked. Any 
CBI markings should not show through the outer envelope.
    Preamble acronyms and abbreviations. Throughout this document the 
use of ``we,'' ``us,'' or ``our'' is intended to refer to the EPA. We 
use multiple acronyms and terms in this preamble.
    While this list may not be exhaustive, to ease the reading of this 
preamble and for reference purposes, the EPA defines the following 
terms and acronyms here:

ACI activated carbon injection
APCD air pollution control device
BACT best available control technology
BDL below detection level
BF board feet
BTF beyond-the-floor
CAA Clean Air Act
CBI Confidential Business Information
CDK continuous dry kiln
CEMS continuous emission monitoring system
CFR Code of Federal Regulations
Cl2 chlorine
CO2e carbon dioxide equivalent
D/F dioxin/furan (i.e., polychlorinated dibenzo-p-dioxins and 
polychlorinated dibenzofurans)
DLL Detection Level Limited
dscm dry standard cubic meter
EJ environmental justice
EPA Environmental Protection Agency
ERT Electronic Reporting Tool
FR Federal Register
gr/dscf grains per dry standard cubic foot
HAP hazardous air pollutant(s)
HCl hydrogen chloride
HF hydrogen fluoride
Hg mercury
ICR information collection request
kPa kilopascals
lb/MSF \3/4\ pounds of pollutant per thousand square feet 
of \3/4\-inch thick board
lb/MSF \3/8\ pounds of pollutant per thousand square feet 
of \3/8\-inch thick board
lb/ODT pounds of pollutant per oven-dried ton of wood
LVL laminated veneer lumber
MACT maximum achievable control technology
MBF thousand board feet
MDF medium density fiberboard
MDI methylene diphenyl diisocyanate
MDL method detection limit
mg/dscm milligrams of pollutant per dry standard cubic meter of air
NAICS North American Industry Classification System
NESHAP national emission standards for hazardous air pollutants
NIST National Institute of Standards and Technology
Non-Hg non-mercury
NRDC Natural Resources Defense Council
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
O&M operation and maintenance
OAQPS Office of Air Quality Planning and Standards

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OMB Office of Management and Budget
OSB oriented strandboard
PAH polycyclic aromatic hydrocarbons
PBCO production-based compliance option
PCWP plywood and composite wood products
PDF portable document format
PM particulate matter
PRA Paperwork Reduction Act
psia pounds per square inch absolute
RCO regenerative catalytic oxidizer
RDL representative detection limit
RFA Regulatory Flexibility Act
RMH resinated material handling
RTO regenerative thermal oxidizer
RTR residual risk and technology review
SBA Small Business Administration
SSM startup, shutdown, and malfunction
TEQ toxic equivalency
THC total hydrocarbon
tpy tons per year
ug/dscm micrograms of pollutant per dry standard cubic meter
UL upper limit
UMRA Unfunded Mandates Reform Act
UPL upper prediction limit
VCS voluntary consensus standards
WESP wet electrostatic precipitator

    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?
III. Analytical Procedures and Decision Making
IV. Analytical Results and Proposed Decisions
    A. What MACT standards are we proposing for direct-fired PCWP 
dryers?
    B. What MACT standards are we proposing for lumber kilns?
    C. What MACT standards are we proposing for process units with 
organic HAP emissions?
    D. What MACT standards are we proposing for process units with 
MDI emissions?
    E. What performance testing, monitoring, and recordkeeping and 
reporting are we proposing?
    F. What other actions are we proposing, and what is the 
rationale for those actions?
    G. What compliance dates are we proposing, and what is the 
rationale for the proposed compliance dates?
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?
    F. What analysis of environmental justice did we conduct?
VI. Request for Comments
VII. Submitting Data Corrections
VIII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act (NTTAA) and 
1 CFR part 51
    J. 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?

    The source category that is the subject of this proposal is Plywood 
and Composite Wood Products regulated under 40 CFR part 63, subpart 
DDDD. The 2022 North American Industry Classification System (NAICS) 
codes for the Plywood and Composite Wood Products industry are 321113, 
321211, 321212, 321215, 321219, and 321999. This list of categories and 
NAICS codes 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.

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.
    A redline/strikeout version of the rule showing the edits that 
would be necessary to incorporate the changes proposed in this action 
to 40 CFR part 63, subpart DDDD, is presented in the memorandum titled 
Proposed Regulation Edits for 40 CFR part 63 Subpart DDDD National 
Emission Standards for Hazardous Air Pollutants: Plywood and Composite 
Wood Products, 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 EPA originally promulgated the PCWP NESHAP (40 CFR part 63, 
subpart DDDD) on July 30, 2004. On August 13, 2020, the EPA took final 
action on the risk and technology review required by Clean Air Act 
(CAA) sections 112(d)(6) and (f)(2) for the PCWP residual risk and 
technology review (2020 RTR). The EPA is proposing in this action to 
amend the NESHAP to ensure that all emissions of HAP from sources in 
the source category are regulated.
    In setting standards for major source categories under CAA section 
112(d), the EPA has the obligation to address all HAP listed under CAA 
section 112(b) emitted by the source category. In the Louisiana 
Environmental Action Network v. EPA (LEAN) decision issued on April 21, 
2020, the U.S. Court of Appeals for the District of Columbia Circuit 
(D.C. Circuit) held that the EPA

[[Page 31859]]

has an obligation to address unregulated emissions from a major source 
category when the Agency conducts the 8-year technology review of a 
maximum achievable control technology (MACT) standard that previously 
left such HAP emissions unregulated.
    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). In the 
2004 NESHAP, 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). The EPA 
acknowledged in the preamble to the proposed RTR (at 84 FR 47077-47078, 
September 6, 2019) that there are unregulated sources with ``no 
control'' MACT determinations in the PCWP source category, and we 
stated our plans to address those units in a separate action subsequent 
to the RTR.
    This proposed rule responds to the partial remand and vacatur of 
the 2004 NESHAP, and to the petition for reconsideration of the 2020 
technology review, and addresses currently unregulated emissions of HAP 
from process units in the PCWP source category, including lumber kilns. 
Six HAP compounds (acetaldehyde, acrolein, formaldehyde, methanol, 
phenol, propionaldehyde), defined as ``total HAP'' in the PCWP NESHAP, 
represent over 96 percent of the HAP emitted from the PCWP source 
category. In addition to total HAP, emissions estimates collected for 
the 2020 RTR indicated that unregulated HAP are present in the PCWP 
source category as a result of combustion in direct-fired dryers, 
including: non-mercury (non-Hg) HAP metals, mercury (Hg), hydrogen 
chloride (HCl), polycyclic aromatic hydrocarbons (PAH), dioxin/furan 
(D/F). There are also emissions of methylene diphenyl diisocyanate 
(MDI) from processes that use MDI resins and coatings. The EPA is 
proposing amendments establishing standards that reflect MACT for these 
pollutants emitted by process units that are part of the PCWP source 
category, pursuant to CAA sections 112(d)(2) and (3) and, where 
appropriate, CAA section 112(h).

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

    The PCWP industry consists of facilities engaged in the production 
of PCWP or kiln-dried lumber. Plywood and composite wood products are 
manufactured by bonding wood material (fibers, particles, strands, 
etc.) or agricultural fiber, generally with resin under heat and 
pressure, to form a structural panel or engineered wood product. 
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, MDF, laminated strand lumber, laminated veneer lumber 
(LVL), wood I-joists, kiln-dried lumber, and glue-laminated beams. 
There are currently 223 major source facilities that are subject to the 
PCWP NESHAP, including 99 facilities manufacturing PCWP and 124 
facilities producing kiln-dried lumber. A major source of HAP is a 
plant site that emits or has the potential to emit any single HAP at a 
rate of 9.07 megagrams (10 tons) or more, or any combination of HAP at 
a rate of 22.68 megagrams (25 tons) or more per year from all emission 
sources at the plant site.
    The affected source under the PCWP NESHAP is the collection of 
dryers, refiners, blenders, formers, presses, board coolers, and other 
process units associated with the manufacturing of PCWP. The affected 
source includes, but is not limited to, green end operations, refining, 
drying operations (including any combustion unit exhaust stream 
routinely used to direct fire process unit(s)), resin preparation, 
blending and forming operations, pressing and board cooling operations, 
and miscellaneous finishing operations (such as sanding, sawing, 
patching, edge sealing, and other finishing operations not subject to 
other NESHAP). The affected source also includes onsite storage and 
preparation of raw materials used in the manufacture of PCWP, such as 
resins; onsite wastewater treatment operations specifically associated 
with PCWP manufacturing; and miscellaneous coating operations. The 
affected source includes lumber kilns at PCWP manufacturing facilities 
and at any other kind of facility.
    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).
    The 2020 residual risk review found that the risk associated with 
air emissions from the PCWP manufacturing industry (including lumber 
kilns) are acceptable and that the current PCWP NESHAP provides an 
ample margin of safety to protect public health. In the 2020 technology 
review, the EPA concluded that there were no developments in practices, 
processes, or control technologies that would warrant revisions to the 
standards promulgated in 2004. In addition to conclusions with respect 
to the RTR, the 2020 action contained amendments to remove exemptions 
from the standards during periods of startup, shutdown, and malfunction 
(SSM). The 2020 amendments added work practices so there would be 
standards in place of the former startup and shutdown exemptions for 3 
specific events that occur during PCWP production: safety-related 
shutdowns, pressurized refiner startup/shutdown, and softwood veneer 
dryer gas-burner relights. Lastly, the 2020 amendments included 
provisions requiring electronic reporting and repeat emissions testing. 
However, the 2020 technology review did not address the unregulated HAP 
emissions from PCWP facilities that the EPA is now addressing in 
response to the 2007 remand of the 2004 NESHAP.

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

[[Page 31860]]

release point characteristics, and HAP emissions data for PCWP process 
units located at major sources. The response rate for the 2017 ICR was 
over 99 percent. Following completion of the 2020 RTR, the EPA 
continued to track facility changes in the PCWP industry to stay 
abreast of the population of facilities subject to the PCWP NESHAP.
    Using information from the 2017 ICR with more recent updates, as 
needed, the EPA assessed emissions test data needs to establish 
standards for unregulated HAPs. On February 28, 2022, the EPA requested 
emissions testing and other information in a CAA section 114 survey of 
20 PCWP facilities operated by 9 companies. The purpose of the 2022 
survey was to gather additional data to use along with the 2017 ICR 
data to establish emission standards for unregulated HAP. The EPA used 
information from both the 2017 ICR and 2022 survey to develop the 
standards proposed in this action. The data collected and used in this 
action are provided in the docket along with documentation of the 
analyses conducted.

III. Analytical Procedures and Decision Making

    The MACT standards proposed in this action were developed pursuant 
to CAA section 112(d)(2) and (3) or, when appropriate, CAA section 
112(h). When developing MACT standards, the ``MACT floor'' for existing 
sources is calculated based on the average performance of the best 
performing units in each category or subcategory and on a consideration 
of the variability of HAP emissions from these units. The MACT floor 
for new sources is based on the emissions levels that are achieved by 
the best performing similar source, with a similar consideration of 
variability. For existing sources, the MACT floor is based on the 
average emission limitation achieved by the best performing 12 percent 
of sources (for which the EPA has emissions information) for source 
categories or subcategories with 30 or more sources, or the average 
emission limitation achieved by the best performing 5 sources (for 
which the EPA has or could reasonably obtain emissions information) for 
categories or subcategories with fewer than 30 sources. To account for 
variability in PCWP manufacturing operations and resulting emissions, 
we calculated the MACT floors using the 99 percent Upper Prediction 
Limit (UPL) using available stack test data.\1\ We note that the MACT 
floors for certain existing and new units are based on limited data 
sets.\2\
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    \1\ For more information regarding the general use of the UPL 
and why it is appropriate for calculating MACT floors, see Use of 
Upper Prediction Limit for Calculating MACT Floors (UPL Memo), in 
the docket for this action.
    \2\ See the memorandum, Approach for Applying the Upper 
Prediction Limit to Limited Datasets, in the docket for this action.
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    The UPL approach addresses variability of emissions data from the 
best performing source or sources in setting MACT standards. The UPL 
also accounts for uncertainty associated with emission values in a 
dataset, which can be influenced by components such as the number of 
samples available for developing MACT standards and the number of 
samples that will be collected to assess compliance with the emission 
limit. The UPL approach has been used in many environmental science 
applications. As explained in more detail in the UPL Memo,\3\ the EPA 
uses the UPL approach to reasonably estimate the emissions performance 
of the best performing source or sources to establish MACT floor 
standards.
---------------------------------------------------------------------------

    \3\ See Use of Upper Prediction Limit for Calculating MACT 
Floors (UPL Memo), in the docket for this action.
---------------------------------------------------------------------------

    Once the UPL is calculated for a pollutant, the representative 
detection limit (RDL) for the pollutant measurement method is 
considered, if necessary. The RDL is representative of the laboratory 
instrument sensitivity and lowest industry-standard method detection 
limits (MDL) achieved when analyzing air pollutant samples. 
Consideration of the RDL is necessary when pollutants are measured near 
or below the detection limit of the analysis method, which was the case 
for some HAP measured in the 2022 survey. The EPA compares a value of 3 
times the RDL (3xRDL) \4\ of the test method to UPL values to ensure 
that the calculated MACT floors account for measurement variability. If 
the 3xRDL value exceeds the MACT floor UPL, the 3xRDL value is 
substituted as the MACT floor emission limit to ensure that the 
standard is set no lower than the minimum level at which emissions can 
reliably be measured. For the cases where we had low detection data, we 
reviewed the memorandum, Data and procedure for handling below 
detection level data in analyzing various pollutant emissions databases 
for MACT and RTR emissions limits, which describes the procedure for 
handling below detection level (BDL) data and developing RDL data when 
setting MACT emission limits.\5\
---------------------------------------------------------------------------

    \4\ The factor of 3 used in the 3xRDL calculation is based on a 
scientifically accepted definition of level of quantitation--simply 
stated, the level where a test method performs with acceptable 
precision. The level of quantitation has been defined as 10 times 
the standard deviation of 7 replicate analyses of a sample at a 
concentration level close to the MDL units of the emission standard. 
That level is then compared to the MACT floor value to ensure that 
the resulting emission limit is in a range that can be measured with 
reasonable precision. In other words, if the 3xRDL value were less 
than the calculated floor (e.g., calculated from the UPL), we would 
conclude that measurement variability has been adequately addressed; 
if it were greater than the calculated floor, we would adjust the 
emissions limit to comport with the 3xRDL value to address 
measurement variability.
    \5\ Westlin/Merrill 2011. Data and procedure for handling below 
detection level data in analyzing various pollutant emissions 
databases for MACT and RTR emissions limits. December 13, 2011, in 
the docket for this action.
---------------------------------------------------------------------------

    In addition, under CAA section 112(d)(2), the EPA must examine more 
stringent ``beyond-the-floor'' regulatory options to determine MACT. 
Unlike the floor minimum stringency requirements, the EPA must consider 
various impacts of the more stringent regulatory options in determining 
whether MACT standards are to reflect beyond-the-floor requirements. 
These impacts include the cost of achieving additional emissions 
reduction beyond that achieved by the MACT floor, any non-air quality 
health and environmental impacts that would result from imposing 
controls beyond the floor, and energy requirements of such beyond floor 
measures. If the EPA concludes that the more stringent regulatory 
options have unreasonable impacts, the EPA selects the MACT floor as 
MACT. However, if the EPA concludes that impacts associated with 
beyond-the-floor levels of control are reasonable in light of 
additional HAP emissions reductions achieved, the EPA selects those 
levels as MACT.
    For some process types, it is not feasible to prescribe or enforce 
a numerical emission standard using the MACT floor and MACT 
determination approach described in CAA sections 112(d)(2) and (3). 
According to CAA section 112(h)(1), MACT standards may take the form of 
design, equipment, work practice, or operational standards if it is not 
feasible in the judgment of the Administrator to prescribe or enforce 
an emission standard. To support a determination that it is not 
feasible to prescribe or enforce an emission standard, CAA sections 
112(h)(2)(A) and (B) require the EPA to determine that either: (A) a 
HAP or pollutants cannot be emitted through a conveyance designed and 
constructed to emit or capture such pollutant, or that any requirement 
for, or use of, such a conveyance would be inconsistent with any 
federal, state or local law, or (B) the application of measurement 
methodology to a particular class of

[[Page 31861]]

sources is not practicable due to technological and economic 
limitations.

IV. Analytical Results and Proposed Decisions

    Section IV.A of this preamble discusses the standards the EPA is 
proposing for combustion-related HAP emissions (non-Hg metals, Hg, HCl, 
PAH, and D/F) from direct-fired PCWP dryers, including rotary strand 
dryers, green rotary dryers, dry rotary dryers, tube dryers, and 
softwood veneer dryers. Section IV.B discusses the standards we are 
proposing for all HAP from lumber kilns. Section IV.C discusses the 
total HAP standards we are proposing for various process units other 
than lumber kilns that also had ``no control'' MACT determinations in 
the 2004 NESHAP that were remanded and vacated. Section IV.D discusses 
the standards we are proposing for process units with MDI emissions, 
including reconstituted wood products presses, blow-line blend tube 
dryers, and miscellaneous coating operations.

A. What MACT standards are we proposing for direct-fired PCWP dryers?

1. Overview
    Direct-fired dryer types. Direct-fired dryers are heated by the 
passing of combustion exhaust through the dryer such that the wood 
material being dried is contacted by the combustion exhaust. Direct-
fired dryers emit combustion-related HAP because emissions from fuel 
burning pass through the dryer and the dryer's air pollution control 
system. There are different designs of PCWP dryers defined in 40 CFR 
63.2292 of the PCWP NESHAP, including the following types of direct-
fired dryers: rotary strand dryers, green rotary dryers, dry rotary 
dryers, tube dryers, softwood veneer dryers (heated zones), fiberboard 
mat dryers (heated zones), and hardboard ovens. Most PCWP direct-fired 
dryers are fired with wood residuals or natural gas (or some 
combination of the 2 fuels). Wood residual fuels include bark, resin-
free residuals, residuals containing resin (e.g., PCWP sander dust and 
trimmings) and mixtures of these wood fuels. Far less commonly for PCWP 
dryers, wood-derived syngas, propane, or fuel oil may be used.
    In addition to the differences in fuel (e.g., wood residuals and 
natural gas) there are differences in drying system configurations. For 
example, direct-fired PCWP dryers can be designed with an individual 
natural gas or wood-fired suspension burner dedicated to a single 
dryer. Other configurations include a combustion unit providing heat to 
multiple dryers. At some facilities, multiple combustion units are used 
to direct-fire one or more dryers. Based on a review of the design 
differences, 2 subcategories for setting MACT standards are being 
proposed for direct-fired PCWP dryers: (1) wood and other fuel-fired 
dryers; and (2) natural gas fuel-fired dryers. We are proposing these 
subcategories of PCWP dryers because combustion units firing wood 
residuals have different design and combustion-related HAP emissions 
profiles from those firing natural gas (or propane). Based on emission 
estimates collected with the 2017 ICR, emissions of non-Hg HAP metals, 
Hg, inorganic gaseous HAPs (HCl, hydrogen fluoride (HF), and chlorine 
(Cl2)), D/F, and PAH in the PCWP source category are 
predominantly associated with wood residual combustion in direct wood-
fired dryers. Subcategorization by fuel type is consistent with other 
NESHAPs, including the major source boiler NESHAP at 40 CFR part 63, 
subpart DDDDD (the Boiler MACT), where EPA subcategorized based on the 
primary fuel combusted in the process and the resulting differences in 
HAP emissions.\6\ We are proposing to add the following definitions to 
the PCWP NESHAP to support subcategorization of direct-fired PCWP 
dryers:
---------------------------------------------------------------------------

    \6\ 75 FR 32017, June 4, 2010.
---------------------------------------------------------------------------

    PCWP dryer means each dry rotary dryer, green rotary dryer, tube 
dryer, rotary strand dryer, hardboard oven, or press predryer; or the 
heated zones from a softwood or hardwood veneer dryer, conveyor strand 
dryer, or fiberboard mat dryer.
    Direct wood-fired PCWP dryer means a direct-fired PCWP dryer in 
which 10 percent or more of the direct-fired annual heat input results 
from combustion of wood-derived fuel such as bark, wood residuals, or 
wood-derived syngas or any other fuel except for natural gas (or 
propane).
    Direct natural gas-fired PCWP dryer means a direct-fired PCWP dryer 
(including each dry rotary dryer, green rotary dryer, tube dryer, 
rotary strand dryer, hardboard oven, press predryer or heated zones 
from a softwood or hardwood veneer dryer, conveyor strand dryer, or 
fiberboard mat dryer) in which greater than 90 percent of the direct-
fired annual heat input results from natural gas (or propane) 
combustion.
    In addition, we are proposing the same definition of natural gas 
that is used in the Boiler MACT. Wood residuals are typically an onsite 
industrial byproduct instead of a purchased fuel. Further 
subcategorization based on the specific type of wood fuel used is not 
recommended because it is common for wood-residual mixtures to be used. 
Wood-derived syngas is considered part of the wood and other fuel 
subcategory although it is not currently used to direct-fire PCWP 
dryers (other than lumber kilns, which are discussed in section IV.B of 
this preamble). All other fuel types (fuel oil, etc.) are uncommon in 
PCWP direct-fired dryers but were included with the ``wood and other 
fuel'' subcategory to ensure that all fuels are covered under the 
standards in the absence of emissions data specific to other fuels. We 
are not proposing further subcategorization based on combustion unit 
design because of the large number of combustion unit and dryer 
combinations that exist, because there would be few units in each 
subcategory for which separate standards at both existing and new 
sources would need to be developed.
    Format of emission limits (units of measure). Each emission limit 
is proposed in 2 formats: (1) concentration; and (2) mass per 
production. Concentration units include grains per dry standard cubic 
foot (gr/dscf) for PM and milligrams per dry standard cubic meter (mg/
dscm) for non-PM pollutants. The concentration units of measure are 
neutral to the type of process and are relevant regardless of whether 
processes of multiple types are co-controlled with PCWP dryers. Mass 
per production units are pounds per thousand square feet (lb/MSF) for 
softwood veneer dryers and pounds per oven dried ton (lb/ODT) for all 
other dryer types. Mass per time (e.g., pounds per hour) was not 
considered as an emission limit format because of the need to normalize 
emissions for the different process throughputs across facilities in 
the industry. Mass per production units such as lb/ODT or lb/MSF 
standardize mass emission rates, so they are applicable to dryers 
across multiple facilities and reflect MACT across a range of 
production rates. These units of measure are commonly used for PCWP 
emission factors.
    Emission limits were developed in 2 formats to provide compliance 
options based on what is achieved by the best performing systems. The 2 
formats proposed provide flexibility for the various process 
configurations subject to the limits and are also helpful because some 
dryers may not be readily equipped for oven-dried production rate 
measurements at the dryer.
    Ranking dryer systems by performance level. Direct-fired PCWP 
dryers have numerous drying system configurations. The overall drying 
system includes the interconnected

[[Page 31862]]

combustion unit(s), dryer(s), and air pollution control devices 
(APCDs). Within any drying system there can be 1 or more combustion 
units, 1 or more dryers, and 1 or more APCDs of different types in 
series or parallel. Given the different combinations of dryers and 
APCDs, we evaluated each set of interconnected combustion units, 
dryers, and APCDs venting to the same emission point(s) as a single 
drying system for purposes of evaluating and ranking performance level. 
For example, 5 dryers venting to one HAP APCD are part of 1 drying 
system with the HAP emission limitation achieved determined at the 
outlet of the HAP APCD. By ranking each system, the outlet emission 
level for the system is considered in the MACT ranking 1 time for the 
entire system, not 5 times for each dryer in the system. The systems 
approach was used to ensure that the various equipment combinations 
from the best performing facilities are accounted for in establishing 
the MACT limits.
    To determine the performance level of a dryer system, we took the 
average of all available lb/production test runs at the APCD outlet. 
For dryer system control configurations with multiple APCD outlets, we 
summed the lb/production numbers from each outlet stack to arrive at 
the total emissions performance level for the dryer system. Once the 
lb/production performance level for each dryer system was determined, 
the dryer systems were ranked to identify the best performing systems 
(i.e., those with the lowest emissions).
    There are fewer than 30 of each type of wood-fired dryer system. 
When there are fewer than 30 sources, the MACT floor for existing 
sources is the average emission limitation achieved by the best 
performing 5 sources (for which the Administrator has or could 
reasonably obtain emissions information), and the MACT floor for new 
sources is the emission control achieved in practice by the best 
controlled similar source. When evaluating MACT floors for the PCWP 
dryers, if we had performance data for more than 5 dryer systems, we 
used the 5 systems with the lowest lb/production performance levels for 
calculating the existing source MACT floor. We used the single best 
performing system with the lowest lb/production performance level to 
calculate the new source MACT floor. The MACT floors in terms of 
emissions concentration were based on the same dryer system rankings.
2. PM and Non-Hg Metals
    The EPA is proposing filterable particulate matter (PM) standards 
as a surrogate for non-Hg HAP metals from wood-fired PCWP dryers. 
Filterable PM is commonly used as a surrogate for HAP metals in 
particulate form including antimony, arsenic, beryllium, cadmium, 
chromium, cobalt, lead, manganese, nickel, and selenium. Air pollution 
control devices that reduce PM also reduce non-Hg HAP metals in 
particulate form. Emissions testing for speciated HAP metals and PM 
from wood-fired PCWP dryers was conducted using EPA Method 29 as part 
of the 2022 CAA section 114 survey. The speciated HAP metals were found 
to be present in the wood-fired PCWP dryer exhaust at levels above the 
detection limit. The 2022 test data, along with PM data from prior test 
reports collected by EPA in the 2017 and 2022 PCWP CAA section 114 
surveys, were used to develop the MACT floors discussed in this section 
of the preamble.
    Rotary strand dryers. There are 27 direct wood-fired rotary strand 
dryer systems in the U.S. including 1 dryer system at a synthetic area 
source. Emissions data for PM are available for 13 direct wood-fired 
rotary strand dryer systems. Because there are fewer than 30 direct 
wood-fired rotary strand dryer systems, the UPL MACT floor calculations 
for existing sources were based on the 5 best performing systems. The 
UPL MACT floor calculation for new sources was based on the best 
performing system. After comparing the UPL calculations to the 
corresponding 3xRDL limits, the PM MACT floor for existing sources, 
based on the UPL, is 9.9E-02 lb/ODT or 3.6E-03 gr/dscf and the PM MACT 
floor for new sources, based on 3xRDL, is 2.8E-02 lb/ODT or 7.0E-04 gr/
dscf. The 3xRDL value was substituted for the lb/ODT UPL in the new 
source MACT floor to ensure that the standards are established at the 
minimum level at which emissions can be measured reliably.
    Most of the direct wood-fired rotary strand dryer systems at major 
sources in the U.S. already operate with PM and HAP control technology 
(e.g., wet electrostatic precipitator followed by a regenerative 
thermal oxidizer, WESP/RTO). The use of WESPs for PM control upstream 
of HAP controls on PCWP rotary strand dryers is prevalent because of 
the high moisture exhaust stream and nature of the particulate 
originating from dryers (e.g., sticky, flammable). Other PM controls 
such as baghouses are not well-suited for controlling PM from these 
sources. No options more stringent than the MACT floor for existing or 
new sources were identified.
    Some existing sources are expected to need to upgrade their WESP to 
meet the existing source MACT floor. One rotary strand dryer system 
with an ESP but no additional HAP control device was assumed to need to 
install a WESP to meet the PM MACT floor and an RTO to achieve the PAH 
MACT floor (discussed under rotary strand dryers in section IV.A.5 of 
this preamble). An estimated 0.32 tpy of non-Hg HAP metals would be 
reduced from existing sources.
    Two new OSB facilities with direct wood-fired rotary stand dryer 
systems are projected to be constructed within the next 5 years. The PM 
MACT floor for new rotary strand dryer systems is achievable with a 
very well-performing WESP/RTO system. An estimated 0.073 tpy non-Hg HAP 
metals would be reduced from new sources.
    Green rotary dryers. There are 7 direct wood-fired green rotary 
dryer systems in the PCWP source category. Emissions data for PM are 
available for 5 direct wood-fired green rotary dryer systems. Because 
there are fewer than 30 direct wood-fired green rotary dryer systems, 
the UPL MACT floor calculations for existing sources were based on all 
5 systems. The UPL MACT floor calculation for new sources was based on 
the best performing system. The PM MACT floor for existing direct wood-
fired green rotary dryer systems is 2.2E-01 lb/ODT or 1.2E-02 gr/dscf 
and the PM MACT floor for new sources is 2.5E-02 lb/ODT or 1.2E-03 gr/
dscf. The wood-fired green rotary dryer systems in the PCWP source 
category already operate with PM and HAP control technology (e.g., 
WESP/RTO or equivalent). No options more stringent than the MACT floor 
for existing or new sources were identified. Zero HAP reduction is 
estimated because all existing and new direct wood-fired green rotary 
dryers are expected to meet their floors with baseline control.
    Dry rotary dryers. There are 9 direct wood-fired dry rotary dryer 
systems in the PCWP source category. Emissions data for PM are 
available for 7 dry rotary dryer systems. Because there are fewer than 
30 direct wood-fired dry rotary dryer systems, the UPL MACT floor 
calculations for existing sources were based on the 5 best performing 
systems. The UPL MACT floor calculation for new sources was based on 
the best performing system. The PM MACT floor for existing direct wood-
fired dry rotary dryer systems is 5.8E-01 lb/ODT or 3.4E-02 gr/dscf and 
the PM MACT floor for new sources is 2.9E-01 lb/ODT or 2.2E-02 gr/dscf. 
The MACT floor is based on the current level of PM control (i.e., 
mechanical collection) in use for existing wood-fired dry rotary dryer 
systems. All of the existing wood-fired dry rotary dryer systems are 
expected to

[[Page 31863]]

meet the PM MACT floor. Therefore, the HAP reduction for the existing 
PM MACT floor is zero. No new direct wood-fired dry rotary dryers are 
projected in the next 5 years.
    We considered a beyond-the-floor option to achieve further PM 
reduction from existing or new direct wood-fired dry rotary dryers 
through the use of a WESP. A WESP could be used alone or as part of a 
WESP/RTO system (as discussed in section IV.A.5 of this preamble as a 
beyond-the-floor measure for PAH emissions) to enable the dry rotary 
dryers to meet the same PM limits as required for green rotary dryers. 
In considering this beyond-the-floor option, we also considered costs, 
non-air quality health and environmental impacts, and energy 
requirements of potentially imposing it as a MACT requirement. 
Nationwide costs of the beyond-the-floor option for existing direct 
wood-fired dry rotary dryers are estimated to be a one-time capital 
cost of $42 million, and annual costs of $10 million per year to 
install and operate a WESP. Nationwide emission reductions are 
estimated to be 56 tpy of PM and 0.17 tpy of non-Hg HAP metals, for a 
cost effectiveness of $181,000 per ton of PM reduced and $61 million/
ton of non-Hg HAP metals reduced. Nationwide use of a WESP to control 
wood-fired dry rotary dryer non-Hg metals would consume an estimated 
23,000 megawatt-hours per year (MWhr/yr) of electricity (with 
associated secondary air emissions), generate 21 million gallons of 
wastewater per year, and produce 4,000 tons of solid waste of per year. 
After considering the costs, environmental, and energy impacts of the 
beyond-the-floor option, the EPA is proposing that the MACT floor 
represents MACT for PM (non-Hg metals) from direct wood-fired dry 
rotary dryers due to the high costs and unfavorable cost effectiveness 
of the more stringent option.
    Tube dryers. There are 11 direct wood-fired primary tube dryer 
systems in the PCWP source category. Emissions data for PM are 
available for 6 direct wood-fired primary tube dryer systems, 2 of 
which have emissions from a secondary tube dryer venting into the 
primary tube dryer. Because there are fewer than 30 direct wood-fired 
tube dryer systems, the UPL MACT floor calculations for existing 
sources were based on the 5 best performing systems. The UPL MACT floor 
calculation for new sources was based on the best performing system. 
The PM MACT floor for existing direct wood-fired tube dryer systems is 
3.1E-01 lb/ODT or 3.1E-03 gr/dscf and the PM MACT floor for new sources 
is 2.0E-02 lb/ODT or 1.3E-03 gr/dscf. No options more stringent than 
the MACT floor for existing or new sources were identified because the 
primary tube dryer systems in the U.S. already operate with PM controls 
(WESP, baghouse, scrubber, etc.) and HAP control technology (RTO or 
biofilter). Zero HAP reduction is estimated because all existing and 
new direct wood-fired tube dryers are expected to meet their respective 
PM MACT floors with baseline control.
    Softwood veneer dryer heated zones. There are 3 softwood veneer 
dryer systems with direct wood-fired heated zones in the PCWP source 
category. Emissions data for PM are available for one direct wood-fired 
softwood veneer dryer system. Since the UPL calculation for existing 
and new sources was based on data from one system, the UPL results for 
existing and new sources are the same. The PM MACT floor for existing 
and new direct wood-fired softwood veneer dryer systems is 7.2E-02 lb/
MSF 3/8'' or 1.5E-02 gr/dscf. We did not identify any options more 
stringent than the MACT floor for existing or new softwood veneer dryer 
systems. All existing direct wood-fired softwood veneer dryers are 
expected to meet the existing floor using the control technology 
already installed; therefore, the HAP reduction for the existing floor 
is zero. Nationwide HAP reductions of the proposed PM MACT floor for 
new sources were not estimated because no new direct wood-fired dry 
softwood veneer dryers are projected in the next 5 years.
3. Mercury (Hg)
    Emissions testing for Hg from wood-fired PCWP dryers was conducted 
using EPA Method 29 as part of the 2022 CAA section 114 survey. The 
data from this testing was used to develop the MACT floors described in 
this section of the preamble. Method 29 collects multiple sample 
fractions that are combined to determine Hg emissions. All of the Hg 
test runs for PCWP dryers were detection level limited (DLL), meaning 1 
or more sample fractions from each run contained no detectable Hg. For 
the purpose of setting MACT standards, the EPA considers DLL test runs 
to contain detectable emissions. The EPA is proposing Hg emission 
limits for direct wood-fired PCWP dryers because all of the Method 29 
test runs had at least 1 sample fraction in which Hg was detected.
    The baseline level of Hg control for PCWP rotary strand, green 
rotary, tube, and softwood veneer dryers is typically a PM and HAP 
control device in series (e.g., WESP/RTO or similar). For dry rotary 
dryers, the baseline level of control is a mechanical collector (e.g., 
multiclone). Due to the low levels of Hg emissions from PCWP dryers, 
which were usually below 3xRDL of the measurement method, the minimum 
level at which emissions can reliably be measured, all PCWP dryers are 
expected to meet the Hg MACT floors for existing and new sources with 
the baseline level of control. No regulatory options more stringent 
than the Hg MACT floors for existing or new wood-fired PCWP dryers were 
identified.
    Rotary strand dryers. Emissions data for Hg are available for 6 
direct wood-fired rotary strand dryer systems. Because there are fewer 
than 30 direct wood-fired rotary strand dryer systems, the UPL MACT 
floor calculations for existing sources were based on the 5 best 
performing systems. The UPL MACT floor calculation for new sources was 
based on the best performing system. After comparing the UPL 
calculations to the corresponding 3xRDL limits, the Hg MACT floor for 
existing direct wood-fired rotary strand dryer systems is 1.6E-05 lb/
ODT or 8.4E-04 mg/dscm, and the Hg MACT floor for new sources is 1.6E-
05 lb/ODT or 8.4E-04 mg/dscm. The 3xRDL values were substituted for 
both UPLs in the existing and new source MACT floors to ensure the 
standards are established at the minimum level at which emissions can 
be measured reliably. No additional Hg reductions are estimated.
    Green rotary dryers. Emissions data for Hg are available for 4 
direct wood-fired green rotary dryer systems. Because there are fewer 
than 30 direct wood-fired green rotary dryer systems, the UPL MACT 
floor calculations for existing sources were based on all 4 systems. 
The UPL MACT floor calculation for new sources was based on the best 
performing system. After comparing the UPL calculations to the 
corresponding 3xRDL limits, the Hg MACT floor for existing direct wood-
fired green rotary dryer systems, based on the UPL, is 1.3E-05 lb/ODT 
or 1.1E-03 mg/dscm, and the Hg MACT floor for new sources, based on 
3xRDL, is 1.1E-05 lb/ODT or 8.4E-04 mg/dscm. The 3xRDL value was 
substituted for the UPL in the new source MACT floor to ensure that the 
standards are established at the minimum level at which emissions can 
be measured reliably. No additional Hg reductions are estimated.
    Dry rotary dryers. Emissions data for Hg are available for 3 direct 
wood-fired dry rotary dryer systems. Because there are fewer than 30 
direct wood-fired dry rotary dryer systems, the UPL MACT floor 
calculations for existing sources were based on all 3 systems. The UPL 
MACT floor calculation for new sources

[[Page 31864]]

was based on the best performing system. After comparing the UPL 
calculations to the corresponding 3xRDL limits, the Hg MACT floor for 
existing and new direct wood-fired dry rotary dryer systems, based on 
3xRDL, is 9.9E-06 lb/ODT or 8.4E-04 mg/dscm. The 3xRDL values were 
substituted for both UPLs in the existing and new source MACT floors to 
ensure that the standards are established at the minimum level at which 
emissions can be measured reliably. No additional Hg reductions are 
estimated.
    Tube dryers. Emissions data for Hg are available for 5 direct wood-
fired primary tube dryer systems, 1 of which has emissions from a 
secondary tube dryer venting into the primary tube dryer. Because there 
are fewer than 30 direct wood-fired tube dryer systems, the UPL MACT 
floor calculations for existing sources were based on all 5 systems. 
The UPL MACT floor calculation for new sources was based on the best 
performing system. After comparing the UPL calculations to the 
corresponding 3xRDL limits, the Hg MACT floor for existing direct wood-
fired tube dryer systems is 2.7E-05 lb/ODT or 1.6E-03 mg/dscm, and the 
Hg MACT floor for new sources is 2.7E-05 lb/ODT or 8.4E-04 mg/dscm. The 
3xRDL values were substituted for the lb/ODT UPLs in the existing and 
new source MACT floors and for the concentration UPL in the new source 
floor to ensure that the standards are established at the minimum level 
at which emissions can be measured reliably. No additional Hg 
reductions are estimated.
    Softwood veneer dryers. Emissions data for Hg are available for 1 
direct wood-fired softwood veneer dryer system. Because the UPL 
calculation for existing and new sources was based on data from one 
system, the UPL results for existing and new sources are the same. The 
Hg MACT floor for existing and new direct wood-fired softwood veneer 
dryer systems is 5.8E-05 lb/MSF 3/8'' or 4.1E-02 mg/dscm. No additional 
Hg reductions are estimated.
4. Acid Gases
    Emissions testing for HCl, HF, and Cl2 from wood-fired 
PCWP dryers was conducted using EPA Method 26A as part of the 2022 CAA 
section 114 survey. Emissions of HF were below detection limit (BDL) in 
99 percent of the EPA Method 26A test runs. Chlorine emissions were BDL 
in 65 percent of the test runs. Emissions of HCl were detected in 71 
percent of the EPA Method 26A test runs. No acid gas emissions were 
detected from the wood-fired softwood veneer dryer tested, and we are, 
therefore, not proposing acid gas standards for this subcategory. Based 
on the available data, we are proposing acid gas emission limits in 
terms of HCl emissions from direct wood-fired rotary strand dryers, 
green rotary dryers, dry rotary dryers, and tube dryers. The data from 
the 2022 emissions testing were used to develop the MACT floors 
discussed in this section of the preamble.
    Rotary strand dryers. Emissions data for HCl are available for 6 
direct wood-fired rotary strand dryer systems. Because there are fewer 
than 30 direct wood-fired rotary strand dryer systems, the UPL MACT 
floor calculations for existing sources were based on the 5 best 
performing systems. The UPL MACT floor calculation for new sources was 
based on the best performing system. After comparing the UPL 
calculations to the corresponding 3xRDL limits, the HCl MACT floor for 
existing direct wood-fired rotary strand dryer systems is 5.8E-03 lb/
ODT or 1.5E-02 mg/dscm and the HCl MACT floor for new sources is 1.7E-
03 lb/ODT or 1.0E-01 mg/dscm. The 3xRDL values were substituted for the 
UPLs in the new source MACT floor to ensure that the standards are 
established at the minimum level at which emissions can be measured 
reliably. No options more stringent than the MACT floor were identified 
for existing or new rotary strand dryers. Zero emissions reduction is 
estimated because all existing direct wood-fired dry rotary dryers are 
expected to meet the HCl MACT floor with current controls.
    The HCl MACT floor for new wood-fired rotary strand dryers is about 
10 percent lower than the average HCl emissions from rotary strand 
dryer systems included in the CAA section 114 tests. Although below the 
average performance level of dryers tested, the HCl MACT floor emission 
level (based on the UPL) has been achieved by 3 rotary strand dryers 
with WESP control and a rotary strand dryer with a multiclone. Thus, 
the new source MACT floor for rotary strand dryers is expected to be 
met with a well-performing WESP system. An example of a well-performing 
WESP is one that incorporates caustic addition (e.g., 1 percent) into 
the WESP recirculation water and has increased blowdown. The 
incremental HCl emission reduction estimated for new wood-fired rotary 
strand dryers using an upgraded WESP is 0.072 tpy.
    Green rotary dryers. Emissions data for HCl are available for 4 
direct wood-fired green rotary dryer systems. Because there are fewer 
than 30 direct wood-fired green rotary dryer systems, the UPL MACT 
floor calculations for existing sources were based on all 4 systems. 
The UPL MACT floor calculation for new sources was based on the best 
performing system. After comparing the UPL calculations to the 
corresponding 3xRDL limits, the HCl MACT floor for existing direct 
wood-fired green rotary dryer systems is 6.5E-03 lb/ODT or 9.7E-01 mg/
dscm, and the HCl MACT floor for new sources is 2.9E-03 lb/ODT or 1.0E-
01 mg/dscm. The 3xRDL value was substituted for the concentration UPL 
in the new source MACT floor to ensure that the standards are 
established at the minimum level at which emissions can be measured 
reliably. No options more stringent than the MACT floor were identified 
for existing or new green rotary dryers, which are already well-
controlled. Zero emissions reduction is estimated because all existing 
and new direct wood-fired green rotary dryers are expected to meet 
their respective HCl MACT floors with baseline controls.
    Dry rotary dryers. Emissions data for HCl are available for 3 
direct wood-fired dry rotary dryer systems. Because there are fewer 
than 30 direct wood-fired dry rotary dryer systems, the UPL MACT floor 
calculations for existing sources were based on all 3 systems. The UPL 
MACT floor calculation for new sources was based on the best performing 
system. After comparing the UPL calculations to the corresponding 3xRDL 
limits, the HCl MACT floor for existing and new direct wood-fired dry 
rotary dryer systems is 1.10E-03 lb/ODT or 1.0E-01 mg/dscm. The 3xRDL 
values were substituted for both UPLs in the existing and new source 
MACT floors to ensure that the standards are established at the minimum 
level at which emissions can be measured reliably. No options more 
stringent than the MACT floor were identified for existing or new dry 
rotary dryers because the MACT floors are based on 3xRDL (i.e., the 
minimum level at which emissions can reliably be measured). Zero 
emissions reduction is estimated because all existing direct wood-fired 
dry rotary dryers are expected to meet the existing HCl MACT floor. No 
new units are projected in the next 5 years.
    Tube dryers. Emissions data for HCl are available for 5 direct 
wood-fired primary tube dryer systems, one of which has emissions from 
a secondary tube dryer venting into the primary tube dryer. Because 
there are fewer than 30 direct wood-fired tube dryer systems, the UPL 
MACT floor calculations for existing sources were based on all 5 
systems. The UPL MACT floor calculation for new sources was based on 
the best performing system. After

[[Page 31865]]

comparing the UPL calculations to the corresponding 3xRDL limits, the 
HCl MACT floor for existing direct wood-fired tube dryer systems is 
6.4E-03 lb/ODT or 7.4E-01 mg/dscm, and the HCl MACT floor for new 
sources is 2.3E-03 lb/ODT or 1.0E-01 mg/dscm. The 3xRDL values were 
substituted for the UPLs in the new source MACT floor to ensure that 
the standards are established at the minimum level at which emissions 
can be measured reliably.
    Existing and new wood-fired tube dryer systems are expected to meet 
the HCl MACT floors with the baseline controls, which typically 
incorporate a WESP or scrubber. No options more stringent than the 
existing and new source MACT floors were identified for primary tube 
dryers. All existing and new direct wood-fired tube dryers are expected 
to meet their HCl MACT floors; therefore, the HAP reduction for both 
floors is zero.
5. PAH
    The EPA is proposing emission limits for PAH emissions that were 
detected in the exhaust from wood-fired rotary strand dryers, green 
rotary dryers, dry rotary dryers, and tube dryers. Emissions testing 
for PAH from wood-fired PCWP dryers was conducted using EPA Other Test 
Method 46 (OTM-46) as part of the 2022 CAA section 114 survey. EPA OTM-
46 is nearly identical to the updated EPA Method 23, for which 
revisions were promulgated on March 20, 2023 (88 FR 16732). The data 
from the 2022 testing was used to develop the MACT floors discussed in 
this section of the preamble. The PAH MACT floors discussed here for 
wood-fired rotary strand dryers, green rotary dryers, dry rotary 
dryers, and tube dryers are greater than the corresponding 3xRDL values 
for PAH. For softwood veneer dryers, the 3xRDL value for PAH is 
proposed as MACT.
    Rotary strand dryers. Emissions data for PAH are available for 6 
direct wood-fired rotary strand dryer systems. Because there are fewer 
than 30 direct wood-fired rotary strand dryer systems, the UPL MACT 
floor calculations for existing sources were based on the 5 best 
performing systems. The UPL MACT floor calculation for new sources was 
based on the best performing system. The PAH MACT floor for existing 
direct wood-fired rotary strand dryer systems is 3.1E-04 lb/ODT or 
2.7E-02 mg/dscm, and the PAH MACT floor for new sources is 3.9E-05 lb/
ODT or 1.4E-03 mg/dscm. The PAH MACT floors are based on dryers that 
already have PM and HAP controls in series. Therefore, no options more 
stringent than the MACT floors were identified for existing or new 
sources.
    Most existing wood-fired rotary strand dryer systems are expected 
to meet the PAH MACT floor with baseline PM and HAP controls in series. 
One rotary strand dryer system with an ESP but no additional HAP 
control device was assumed to need to add a WESP to meet the PM MACT 
floor and an RTO to achieve the PAH MACT floor. Nationwide emission 
reductions of the proposed MACT floor for PAH for existing direct wood-
fired rotary strand dryers are estimated to be 0.043 tpy of PAH reduced 
and 130 tpy of VOC reduced.
    New wood-fired rotary strand dryer systems are expected to be 
challenged to meet the stringent new source PAH MACT floor in spite of 
coming online with a WESP/RTO control system. While the new source MACT 
floor emission level based on the UPL has been achieved by rotary 
strand dryers with multiclone/RTO and WESP/RTO controls, the new source 
PAH MACT floor is 90 percent lower than the average PAH performance 
level achieved by the well-controlled rotary strand dryers in the CAA 
section 114 emission tests. The burner tune-up requirements required 
for all direct-fired PCWP dryers are expected to help with meeting the 
PAH MACT floor. Nationwide, 0.15 tpy of PAH reductions are estimated to 
be associated with the proposed PAH MACT floor.
    Green rotary dryers. Emissions data for PAH are available for 4 
direct wood-fired green rotary dryer systems. Because there are fewer 
than 30 direct wood-fired green rotary dryer systems, the UPL MACT 
floor calculations for existing sources were based on all 4 systems. 
The UPL MACT floor calculation for new sources was based on the best 
performing system. The PAH MACT floor for existing direct wood-fired 
green rotary dryer systems is 9.0E-03 lb/ODT or 4.1E-01 mg/dscm, and 
the PAH MACT floor for new sources is 2.6E-05 lb/ODT or 4.4E-03 mg/
dscm. The PAH MACT floors are based on dryers that already have PM and 
organic HAP controls in series. Therefore, no options more stringent 
than the MACT floors were identified for existing or new sources. No 
reductions in PAH were estimated because existing wood-fired green 
rotary dryer systems are expected to meet the PAH MACT floor with 
baseline HAP controls. The burner tune-up requirements required for all 
direct-fired PCWP dryers are expected to help with meeting the PAH MACT 
floor. No options more stringent than the MACT floor were identified 
for new sources. No reductions in PAH are estimated because new direct 
wood-fired green rotary dryers are expected to meet the MACT floor with 
proper tuning.
    Dry rotary dryers. Emissions data for PAH are available for 3 
direct wood-fired dry rotary dryer systems. Because there are fewer 
than 30 direct wood-fired dry rotary dryer systems, the UPL MACT floor 
calculations for existing sources were based on all 3 systems. The UPL 
MACT floor calculation for new sources was based on the best performing 
system. The PAH MACT floor for existing direct wood-fired dry rotary 
dryer systems is 4.3E-04 lb/ODT or 3.9E-02 mg/dscm, and the PAH MACT 
floor for new sources is 2.5E-05 lb/ODT or 2.2E-03 mg/dscm.
    All existing direct wood-fired dry rotary dryers are expected to 
meet the existing PAH MACT floor with the baseline controls (mechanical 
collection); therefore, the HAP reduction for the existing floor is 
zero. No new direct wood-fired dry rotary dryers are projected in the 
next 5 years. If a new wood-fired dry rotary dryer were to be 
installed, it is estimated that some facilities may need an RTO to meet 
the new source PAH MACT floor.
    We considered a beyond-the-floor option for existing and new wood-
fired dry rotary dryers to use a HAP control system that meets the 
limits in table 1B to subpart DDDD of 40 CFR part 63, which we 
anticipate would be based on use of a WESP/RTO system. The WESP would 
protect the RTO from particulate build up and is a beyond-the-floor 
option for PM for dry rotary dryers. The costs and other impacts of 
using a WESP on wood-fired dry rotary dryers were discussed in section 
IV.A.2 of this preamble. Nationwide costs of the beyond-the-floor 
option to reduce PAH from existing direct wood-fired dry rotary dryers 
using an RTO are estimated to be a one-time capital cost of $16 million 
and annual cost of $6.8 million per year. Nationwide HAP and VOC 
reductions for existing sources are estimated to be 18 tpy of organic 
HAP (including 0.016 tpy of PAH) and 282 tpy of VOC for a cost 
effectiveness of $383,000/ton of organic HAP reduced, $431 million/ton 
of PAH reduced, and $24,000/ton of VOC reduced. Nationwide energy 
impacts are estimated to be consumption of 23,000 MWhr/yr of 
electricity, with associated secondary air emissions, and 371,000 
MMBtu/yr of natural gas. Nationwide wastewater (e.g., for RTO washouts) 
and solid waste impacts are estimated to be 273,000 gallons of 
wastewater per year and 84 tons of solid waste of per year. Nationwide 
costs and impacts of the beyond-the-floor option for PAH for

[[Page 31866]]

new direct wood-fired dry rotary dryers were not estimated as no new 
direct wood-fired dry rotary dryers are projected in the next 5 years.
    After considering the costs, non-air quality environmental, and 
energy impacts of the beyond-the-floor option for PAH, we are proposing 
that MACT is represented by the PAH MACT floor. We rejected the more 
stringent beyond-the-floor option based on use of a WESP/RTO system 
because of its high costs, unfavorable cost effectiveness, energy 
usage, and non-air-quality environmental impacts.
    Tube dryers. Emissions data for PAH are available for 5 direct 
wood-fired primary tube dryer systems, one of which has emissions from 
a secondary tube dryer venting into the primary tube dryer. Because 
there are fewer than 30 direct wood-fired tube dryer systems, the UPL 
MACT floor calculations for existing sources were based on all 5 
systems. The UPL MACT floor calculation for new sources was based on 
the best performing system. The PAH MACT floor for existing direct 
wood-fired tube dryer systems is 3.0E-04 lb/ODT or 3.3E-03 mg/dscm, and 
the PAH MACT floor for new sources is 1.2E-05 lb/ODT or 6.3E-04 mg/
dscm. The PAH MACT floors are based on tube dryer systems that already 
have PM and HAP controls in series. Therefore, no options more 
stringent than the MACT floors were identified for existing or new 
primary tube dryers. Because all existing and new direct wood-fired 
tube dryers are expected to meet their MACT floors for PAH with 
baseline HAP controls, zero HAP reduction is estimated.
    Softwood veneer dryers. There are 3 softwood veneer dryer systems 
with direct wood-fired heated zones in the PCWP source category. 
Detectable PAH emissions are not expected from these dryers. Direct-
wood fired softwood veneer dryers were not included in the CAA section 
114 testing using EPA OTM-46 because veneer dryers operate at lower 
temperature with less mixing than rotary and tube dryers and, 
therefore, are not expected to have the same potential for formation of 
detectable PAH emissions as direct wood-fired rotary and tube dryers, 
which operate at higher temperatures under more turbulent conditions. 
However, given that PAH emissions were measured in the exhaust from 
other wood-fired PCWP dryers, absent PAH test data, we are proposing a 
PAH limit of 3.3E-05 mg/dscm based on 3xRDL for existing and new direct 
wood-fired softwood veneer dryers. We anticipate that this limit would 
be met through the same burner tune-up standards proposed to be 
required for all wood-fired dryers as well as using the incineration-
based controls already in place on the softwood veneer dryers. Thus, no 
emission reductions are estimated, and no options more stringent than 
the 3xRDL value were identified for existing or new wood-fired softwood 
veneer dryers. The EPA requests submittal of available PAH emissions 
information for wood-fired softwood veneer dryers to help inform the 
final rule.
6. Burner Tune-Up Standards
    The EPA is proposing burner tune-up standards to address dioxin/
furan (D/F) from wood and other fuel fired dryers, any combustion-
related HAP that may be emitted from natural-gas fired PCWP dryers, and 
any HAP from combustion unit bypass stacks. As discussed in section 
IV.B of this preamble, burner tune-ups are also being proposed as a 
standard for direct-fired lumber kilns to address combustion-related 
HAP from direct fuel firing and kiln combustion unit bypass stacks.
a. D/F From Wood-Fired PCWP Dryers
    Emissions testing for D/F from wood-fired PCWP dryers was conducted 
using EPA OTM-46 as part of the 2022 CAA section 114 survey. The EPA 
conducted a detection limit evaluation on the D/F emissions test runs 
gathered from the 2022 CAA section 114 requests for wood-fired PCWP 
dryers. Over 70 percent of the D/F congener test runs were BDL. When 
considered on a toxic equivalency (TEQ) basis, 89 percent of test runs 
were below the 3xRDL value for TEQ. The EPA considers a work practice 
to be justified if a significant majority of emissions data available 
indicate that emissions are so low that they cannot be reliably 
measured (e.g., more than 55 percent of test runs are non-detect).\7\ 
Therefore, a work practice standard is being proposed for D/F from 
wood-fired PCWP dryers. The proposed work practice for existing and new 
PCWP dryers is an annual tune-up of the burners that provide direct 
heat to PCWP wood-fired dryers in order to ensure good combustion and, 
therefore, minimize emissions of organic HAP.
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    \7\ See the June 5, 2014, memorandum, Determination of 
`non[hyphen]detect' from EPA Method 29 (multi[hyphen]metals) and EPA 
Method 23 (dioxin/furan) test data when evaluating the setting of 
MACT floors versus establishing work practice standards, in the 
docket for this action.
---------------------------------------------------------------------------

    Nationwide HAP reductions of the proposed work practice for D/F for 
existing direct wood-fired PCWP dryers are estimated to be 5.9 tpy of 
all HAP reduced (including 2.43E-06 tpy of D/F). Nationwide HAP 
reductions of the proposed work practice for D/F for new and 
reconstructed direct wood-fired PCWP dryers are estimated to be 0.20 
tpy of HAP reduced (including 1.34E-07 tpy of D/F).
b. Natural-Gas Fired PCWP Dryers
    Combustion-related HAP emissions from combustion units burning 
natural gas to directly fire PCWP dryers are similar to emissions from 
boilers and process heaters that burn natural gas. Under the Boiler 
MACT, ``units designed to burn gas 1 fuels'' (i.e., units burning 
natural gas) were required to conduct periodic tune-ups as part of a 
work practice for non-Hg HAP metals, Hg, acid gases, D/F, and organic 
HAP. As explained at 76 FR 15637-38 (March 21, 2011), measured 
emissions of these pollutants from natural gas-fired boilers and 
process heaters were routinely found to be below the detection limits 
of EPA test methods, and, as such, the EPA found it technically and 
economically impracticable to reliably measure emissions from these 
units. The combustion unit tune-up work practice was identified as an 
effective HAP emissions standard for natural gas-fired PCWP dryers that 
combust the cleanest fuels available. Based on that conclusion, we are 
proposing a burner tune-up work practice standard for combustion-
related HAP, including non-Hg metals, Hg, acid gases, D/F, and PAH, 
from existing and new direct natural gas-fired PCWP dryers. In addition 
to the proposed burner tune-up work practice standard for combustion-
related HAP from direct gas-fired PCWP dryers, the current emission 
standards for PCWP dryers (40 CFR 63.2240(b)) already limit organic HAP 
emissions, including organic HAP emitted from natural gas combustion 
and organic HAP from the drying process. Nationwide combustion HAP 
reductions of the proposed tune-up work practice standard are estimated 
to be 0.10 tpy for existing sources and 0.0073 tpy for new sources.
c. Combustion Unit Bypass Stacks
    Combustion-related HAP emissions can be emitted for brief periods 
of time from bypass stacks located between a combustion unit and PCWP 
dryer (or lumber kiln) direct-fired by the combustion unit when the 
dryer (or kiln) is unable to accept the hot exhaust from the direct-
firing combustion unit. It is not feasible to prescribe numeric 
emission standards for combustion-related HAP emissions briefly emitted 
from bypass stacks between the combustion unit and dryer (or lumber 
kiln). Emissions measurement methodologies, including stack tests

[[Page 31867]]

which require hours to complete, are not feasible for PCWP combustion 
unit bypasses that last minutes at a time. Use of a continuous emission 
monitoring system (CEMS) to capture these events is not feasible due to 
calibration issues and the need to perform relative accuracy test 
audits (RATA), which involve stack tests. Establishing parameter limits 
correlated with emissions also is not feasible because this would be 
done through stack testing. Therefore, we are proposing a work practice 
standard for existing and new combustion bypass stacks associated with 
direct-fired PCWP dryers or direct-fired lumber kilns regardless of 
fuel type. The work practice standard would require an annual tune-up 
of the burner associated with the bypass stack, along with monitoring 
and reporting bypass stack usage. Bypass stack usage time would be 
monitored using an indicator such as bypass damper position or 
temperature in the bypass stack. No feasible options more stringent 
than burner tune-ups coupled with bypass stack usage monitoring were 
identified for existing or new combustion bypass stacks. No HAP 
reductions were estimated in conjunction with bypass stack monitoring.

B. What MACT standards are we proposing for lumber kilns?

    The EPA is proposing standards to limit emissions of all HAP from 
lumber kilns. All HAP emissions would be limited by the work practices 
the EPA is proposing that would limit over-drying of lumber. 
Combustion-related HAP emissions from direct-fired kilns would be 
further limited by the proposed burner tune-up standards. Additional 
information on our review of information pertaining to lumber kilns is 
available in the memorandum, Development of National Emission Standards 
for Hazardous Air Pollutant Emission Standards for Lumber Drying Kilns, 
in the docket for this action.
1. Lumber Kiln Overview
    Lumber kilns can be characterized by wood type (softwood or 
hardwood), design (batch or continuous), and heating method (indirect- 
or direct-fired). Although few hardwood lumber kilns are located at 
major sources, we are proposing to include both hardwood and softwood 
lumber kilns in the PCWP NESHAP so HAP standards would apply to any 
lumber kiln located at a PCWP or lumber facility that is a major source 
of HAP emissions.
    In batch kilns, lumber is loaded into the kiln where it remains 
stationary during the entire drying cycle. When drying is complete, the 
batch kiln is shut down to remove the lumber. The kiln is restarted 
again after it is loaded with a new batch of lumber. Batch kilns can be 
either track-loaded, where multiple packages \8\ of lumber are pushed 
into the kiln on tracks at once, or smaller package loaded kilns, where 
lumber packages are loaded in the batch kiln with a forklift. The track 
loaded kilns tend to have higher annual throughput and are the type of 
batch kilns most commonly used at major source PCWP facilities.
---------------------------------------------------------------------------

    \8\ Packages are stacks of boards layered with small strips of 
wood called ``stickers'' to allow for air to circulate around the 
boards while the boards are drying in the kiln.
---------------------------------------------------------------------------

    Batch kilns typically have numerous roof vents positioned in rows 
down each side of the kiln's roof. The vents open and close throughout 
the drying cycle as the temperature and humidity in the kiln change. 
Internal fans under the kiln roof circulate air around the packages of 
lumber. The fans change direction every 2 to 3 hours to provide even 
drying of the lumber. Consequently, one bank of roof vents is normally 
exhausting hot, moist air while the other row of vents is allowing 
ambient air into the kiln. The direction of flow cycles between air 
intake and exhaust throughout the drying cycle. Batch kilns release 
fugitive air emissions from doors or cracks in the kiln exterior due to 
pressure differences between the interior of the kiln and ambient 
conditions outside the kiln.
    Over the past decade, continuous dry kilns (CDKs) have become 
popular for drying southern pine lumber in the U.S. Southeast. Unlike 
batch kilns, CDKs do not have to be shut down for loading and 
unloading. In CDKs, lumber travels continuously through the kiln on 
tracks. Most CDKs in the U.S. have a ``counter-flow'' design where 2 
sets of lumber travel in opposite directions to one another such that 
on one end of the kiln green lumber enters the kiln parallel to dry 
lumber exiting the kiln. This design allows heat from the dried lumber 
coming out of the kiln to preheat the incoming green lumber to conserve 
energy. There are no doors on CDKs, allowing the constant flow of 
lumber into and out of each end of the kiln. Thus, CDKs release exhaust 
containing steam and fugitive emissions from their open ends. Some CDKs 
have powered or unpowered hoods or stacks over their openings to direct 
a portion (e.g., 40 to 80 percent of the volume) of exhaust upward 
while the remaining exhaust exits through the kiln ends.
    In addition to batch or continuous design, another key design 
feature of lumber kilns is their heating method. Indirect-fired kilns 
are heated with steam from a boiler. The steam circulates through coils 
in the path of air circulation within the kiln. Direct-fired kilns use 
hot gases from fuel combustion to heat the kiln such that the kiln 
exhaust contains emissions from wood drying and fuel combustion. 
Combustion units used to direct-fire kilns may be a dedicated burner 
for each kiln or a combustion unit that direct-fires multiple kilns. 
Fuels used to direct-fire kilns include natural gas, wood, or wood-
derived syngas generated in a gasifier. Wood is often used for direct-
fired lumber kilns because it is a readily available byproduct of 
lumber manufacturing and is typically generated onsite. Gasifiers 
typically use green sawdust generated from cutting logs into boards. 
The green sawdust is first gasified under sub-stoichiometric conditions 
to produce a syngas that is then burned in a secondary combustion 
chamber to directly fire the kiln. Regardless of fuel, combustion gases 
are usually too hot for direct introduction into the kiln, so they are 
diluted with recirculated kiln exhaust and ambient air in a blend box 
prior to introduction to the kiln.
    The EPA has identified 680 lumber kilns at major source PCWP 
facilities subject to 40 CFR part 63, subpart DDDD, including:
     11 batch, indirect-fired, hardwood kilns.
     203 batch, indirect-fired, southern yellow pine (SYP) 
kilns.
     241 batch, indirect-fired, other (e.g., western) softwood 
kilns.
     103 batch, direct-fired, SYP kilns.
     98 continuous, direct-fired, SYP kilns.
     24 continuous, indirect-fired, SYP kilns.
    None of the lumber kilns identified operate with any add-on air 
pollution controls. Emission factors that have been adopted by 
regulatory agencies and lumber producers for emission estimation 
purposes were mostly derived from small-scale kiln tests and a few 
(often research-level) tests of full-scale kilns. This information is 
useful for estimating emissions for inventory reporting purposes but is 
not suitable for developing or enforcing national emission standards 
due to the impracticality of capturing and measuring lumber kiln 
emissions (discussed in more detail later in this preamble). A 
significant challenge to measuring batch and continuous lumber kiln 
emissions is accurate determination of the total lumber kiln gas flow 
rate and the need to extrapolate concentrations from 1 or 2 sampling 
locations to

[[Page 31868]]

estimate total kiln emissions from several emission points (including 
fugitives).
    Because of the infeasibility of lumber kiln emissions collection 
and control, and because of measurement challenges, many facilities and 
permit authorities have established work practices for limiting organic 
emissions from lumber kilns. Good design and operating practices were 
determined to be the best available control technology (BACT) for 
several lumber kilns. A review of BACT determinations for new and 
modified kilns is relevant because a work practice can be found as BACT 
only after a permitting authority finds that technological or economic 
limitations on the application of measurement methodology to a 
particular emissions unit would make use of a numerical emission 
standard infeasible.\9\ This finding is similar to the requirements 
under CAA section 112(h) for concluding that MACT is represented by a 
work practice or operational standard.
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    \9\ The regulatory definition of BACT in 40 CFR 52.21(b)(12) 
states, ``If the Administrator determines that technological or 
economic limitations on the application of measurement methodology 
to a particular emissions unit would make the imposition of an 
emissions standard infeasible, a design, equipment, work practice, 
operational standard, or combination thereof, may be prescribed 
instead to satisfy the requirement for the application of best 
available control technology. Such standard shall, to the degree 
possible, set forth the emissions reduction achievable by 
implementation of such design, equipment, work practice or 
operation, and shall provide for compliance by means which achieve 
equivalent results.''
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2. Rationale for Work Practices
    Given the impracticability of capturing and measuring emissions 
from lumber kilns, we have concluded that the criteria in CAA section 
112(h) for establishing a design, equipment, work practice, or 
operational standard apply for lumber kilns. CAA section 112(h) states 
that if it is not feasible in the judgment of the Administrator to 
prescribe or enforce an emission standard for control of a HAP, the 
Administrator may, in lieu thereof, promulgate a design, equipment, 
work practice, or operational standard, or combination thereof, which 
in the Administrator's judgment is consistent with the provisions of 
CAA section 112(d). The phrase ``not feasible to prescribe or enforce 
an emission standard'' is further defined in CAA section 112(h)(2)(A) 
and (B) as any situation in which the Administrator determines that: 
(A) a hazardous air pollutant or pollutants cannot be emitted through a 
conveyance designed and constructed to emit or capture such pollutant, 
or (B) the application of measurement methodology to a particular class 
of sources is not practicable due to technological and economic 
limitations.
    Relative to CAA section 112(h)(2)(A), the total volume of lumber 
kiln emissions cannot be emitted through a conveyance that is designed 
and constructed to emit or capture HAP emissions. For example, batch 
kilns have numerous vents that cycle between air intake and exhaust in 
addition to some fugitive emissions that can be emitted from the kiln 
doors or walls. Batch kilns do not and cannot have conveyances to 
capture emissions from the exhaust vents or eliminate the air intake, 
as such conveyances would disrupt the drying process by limiting air 
flow into the kiln. If constructed, flow exiting a conveyance would be 
intermittent (cyclical) just as it is from each kiln vent, meaning a 
conveyance would not help with measuring emissions as needed to 
prescribe or enforce a numeric emission standard. Similarly, CDKs have 
considerable amounts of fugitive emissions from their openings that 
cannot be eliminated while allowing for lumber to enter and exit the 
kiln. While some CDKs have passive hoods or stacks (which may be 
powered or unpowered) at their ends to direct a fraction of the kiln 
exhaust upward to improve dispersion, these devices do not and cannot 
eliminate the fugitive emissions from the CDK openings. If powered 
stacks were added to draw more air out of the CDK in an attempt to 
eliminate the fugitives to obtain a reliable emissions measurement, the 
energy-transfer function of the CDK, in which heat and steam from the 
exiting lumber are used to precondition incoming lumber, would be lost. 
Thus, it is not possible to capture emissions from the openings at each 
end or directly measure the total gas flow rate from a CDK as needed to 
prescribe or enforce an emission limit.
    Relative to CAA section 112(h)(2)(B), there are technological and 
economic limitations to applying a measurement methodology for lumber 
kilns as needed to prescribe or enforce a numeric emission standard. 
For batch kilns, with numerous vents cycling between air intake and 
exhaust, and temperature and humidity changes throughout the batch 
cycle, there is not a consistent flow rate or concentration to measure 
using conventional stack test methods or continuous emission monitors. 
Direct measurement of flow rate from batch kilns is not technically 
feasible because of the numerous vents and changing flow direction. In 
addition to the need to test multiple vents, an economic limitation to 
testing batch kilns is the expense associated with testing over the 
long batch kiln cycle (e.g., often 20 or more hours) in which the 
emission concentration and kiln parameters change throughout the cycle. 
For CDKs, direct measurement of total kiln exhaust flow is not 
technically feasible due to the significant volume of fugitive 
emissions from the kiln openings. In addition to being unable to 
measure total flow, many CDKs have no specific emission point (or 
conduit) in which to measure emissions concentration (e.g., no outlet 
stack or hood, or in an indirect-fired kiln no kiln air return duct to 
a burner). This lack of a specific emission point for measurement of 
total kiln air flow and concentration is also an economic limitation, 
because even if outlet vents suitable for testing were present for a 
portion of exhaust, all such vents would need to be tested to ensure 
uniformity of concentration or to establish vent-specific 
concentrations, which would greatly increase source testing costs 
(while total flow would continue to remain uncertain, limiting 
usefulness of the data for prescribing or enforcing an emission 
standard).
3. Lumber Kiln Work Practice Standard
    Work practices to reduce emissions from lumber kilns are often 
based on measures to minimize the amount of over-dried lumber produced. 
Lumber over-drying is of concern because HAP emissions have been shown 
to increase after the free water from the lumber is removed. As the 
free water evaporates, water bound within the cellular structure of the 
wood begins to be removed. Once the evaporative cooling of moisture on 
the surface of lumber ceases, the temperature of the lumber in the kiln 
increases and organic HAP emissions begin to increase. A work practice 
that minimizes over-drying limits organic HAP emissions from all types 
of kilns as well as combustion-related HAP emissions from direct-fired 
kilns since minimizing over-drying reduces fuel consumption, which 
results in less combustion-related HAP.
    To develop a work practice standard for lumber kilns, we reviewed 
various permits and other information, including information received 
from ICR respondents regarding design, operation, and monitoring 
methods to minimize over-drying and limit HAP emissions. Several 
permits included ``good operating practices'' and kiln inspection and 
maintenance requirements to minimize over-drying. We also found that 
lumber manufacturers use a variety of practices to ensure that lumber 
is properly dried while balancing energy usage. For many manufacturers, 
the focus is on ensuring

[[Page 31869]]

that the lumber meets grade classification, which can be accomplished 
using a variety of techniques. For example, to meet the moisture 
content grade ``KD19'' for southern pine lumber, manufacturers must dry 
lumber to a maximum of 19 percent moisture. There are moisture grades 
other than KD19, such as KD15 or lower, for lumber to be exported. 
Lumber or wooden poles that will later undergo treatment may be dried 
to higher moisture levels than KD19. To ensure that the maximum grade 
moisture is met by most boards in the kiln load, kiln operators need to 
dry to a target moisture a few percent below the maximum moisture 
grade. Methods used to determine dryness of lumber vary. Temperature 
parameters monitored in the kiln during drying (e.g., wet or dry bulb 
temperature or temperature drop across the load) are used by kiln 
operators to determine when the drying cycle is complete. Temperature 
monitoring may be paired with hot checks in which sample boards are 
pulled from the kiln and checked for dryness near the end of the kiln 
cycle. In-kiln lumber moisture measurement during drying may be used, 
or lumber moisture may be checked with hand-held moisture meters after 
the drying cycle concludes. It is also common for lumber moisture 
measurement to be conducted downstream of the kiln (e.g., hand-held 
moisture meter checks or in-line moisture monitoring at the planer 
before lumber is packaged for shipment). Of the methods available for 
determining lumber moisture, the in-line moisture meter at the planer 
typically produces the largest number of lumber moisture readings. 
Given different kiln designs and the wide variety of techniques used to 
determine lumber dryness, the work practice to limit over-drying in the 
kiln requires some flexibility for site-specific considerations.
    Based on our review of methods for limiting lumber over-drying, in 
40 CFR 63.2241(d) we are proposing a work practice standard with 4 
elements: (1) operation and maintenance for all kilns, (2) burner tune-
up for direct-fired kilns, (3) a work practice option in which all 
kilns limit over-drying by operating below a temperature set point, 
conducting in-kiln moisture monitoring, or following a site-specific 
plan (for temperature and lumber moisture monitoring), and (4) minimum 
kiln-dried lumber moisture content limits below which lumber is 
considered to be over-dried lumber for all kilns for purposes of the 
PCWP NESHAP.
    Operation and maintenance (O&M) plan. For the first element of the 
work practice, we are proposing that facilities develop an O&M plan for 
all the lumber kilns located at the facility. Documentation of the O&M 
plan would be required to be retained onsite and to include procedures 
for maintaining the integrity of lumber kiln internal air flow and heat 
distribution components (e.g., baffles, fans, vents, heating coils, and 
temperature sensors) to provide as uniform a temperature and air flow 
as reasonably possible. Maintaining the heat distribution components 
prevents hot spots that could lead to increased HAP emissions and also 
prevents cold spots in the kiln that could lengthen the drying cycle 
for the entire load, thereby avoiding higher HAP emissions. The O&M 
plan would be required to include charge optimization practices to 
promote uniformity in lumber charged into the kiln (e.g., sizing, 
sorting, stickering, conditioning). Proper sorting results in less 
variation per kiln load that could lengthen the drying cycle and 
increase HAP emissions, and proper stickering ensures that air can flow 
through the lumber packages.\10\ To demonstrate compliance with the O&M 
plan, the facility would be required to conduct an annual inspection of 
lumber kiln integrity and review the charge optimization practices 
used. Facilities would be required to implement corrective actions (as 
needed) and maintain records of inspections and corrective actions 
taken under the O&M plan. State authorities delegated responsibility 
for implementing 40 CFR part 63, subpart DDDD, (or ``delegated 
authorities'') may require modification of the O&M plan, as needed, 
upon review.
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    \10\ Additional information on lumber kiln O&M can be found in 
Simpson, William T., ed. 1991. Dry Kiln Operator's Manual. 
Agricultural Handbook AH-188. Madison, WI: U.S. Department of 
Agriculture, Forest Service, Forest Products Laboratory.
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    Kiln burner tune-up. For the second element of the work practice, 
we are proposing that facilities with batch and continuous direct-fired 
kilns conduct an annual burner tune-up to reduce the potential for 
combustion-related HAP emissions beyond the reduction in these 
emissions that results from minimizing lumber over-drying. Properly 
operating burners would reduce the potential for combustion-related HAP 
emissions from the kiln during routine operation and from any bypass 
stacks used temporarily during startup or shutdown of the kiln burner. 
We are proposing annual tune-ups for lumber kilns following the same 
procedures proposed for PCWP dryers.
    Temperature, moisture, or site-specific plan limits. For the third 
element, we are proposing that facilities select from 1 of 3 work 
practice options for minimizing lumber over-drying for each kiln at the 
facility: (1) temperature set point, (2) in-kiln moisture monitoring, 
or (3) a site-specific plan (for temperature and lumber moisture 
monitoring). While the EPA could require a site-specific plan for all 
lumber kilns, we acknowledge that lumber kilns operating at moderate 
temperatures compared to kilns of similar design, or kilns equipped 
with in-kiln moisture monitoring, are already operating in a manner 
that minimizes rapid over-drying. Thus, we are proposing to provide two 
streamlined options (in lieu of requiring a site-specific plan) for 
lumber kilns operating at moderate temperatures or using in-kiln lumber 
moisture monitoring techniques that reduce the potential for over-
drying. These options consider that over-drying can occur more rapidly 
in kilns operating at higher temperatures and/or without a direct in-
kiln lumber moisture content measurement system that provides automatic 
feedback to the kiln operator. These options encompass kiln features 
likely to be included in a site-specific plan to minimize over-drying 
(if a plan were to be developed for the kiln). These compliance 
demonstration alternatives to a site-specific plan streamline 
compliance for kilns that have less potential for over-drying and 
reduce burden for the delegated authority reviewing the site-specific 
plan.
    Under the temperature option, the lumber kiln would be operated 
with a maximum dry bulb temperature set point of no more than 210 
[deg]F for batch indirect-fired (IF) kilns, 235 degrees Fahrenheit 
([deg]F) for batch direct-fired kilns, or 245 [deg]F for continuous 
indirect-fired or continuous direct-fired kilns. The proposed 
temperatures of 210 [deg]F, 235 [deg]F, and 245 [deg]F represent both 
average and median dry bulb temperature used in lumber kilns in the 
source category that were within 5 [deg]F of the proposed temperature. 
These temperatures are proposed because they represent temperatures 
below which approximately half of kilns operate while the remaining 
half of kilns operate at higher temperatures that could accelerate 
over-drying. Facilities would be required to continuously measure the 
dry bulb temperature during the kiln drying cycle, record the dry bulb 
temperature at least every 15 minutes, calculate the 3-hour block 
average temperature, and maintain the 3-hour block average below the 
temperature limit. See proposed 40 CFR 63.2269(a)-(b) and (m) and 40 
CFR 63.2270(h) for more details on

[[Page 31870]]

temperature monitoring under the PCWP NESHAP.
    Under the in-kiln moisture measurement option, the lumber kiln 
would operate using a direct, in-kiln continuous lumber moisture 
monitoring technique that provides automated feedback from within the 
kiln to the kiln operator control panel during the drying cycle. Kiln 
owners and operators would be required to operate the kiln to dry to a 
semiannual average lumber moisture content above the minimum limit of 
moisture content proposed in paragraph 40 CFR 63.2241(e)(3)(ii) and 
table 11 to subpart DDDD of 40 CFR part 63, as discussed later in this 
preamble. We are proposing the in-kiln lumber moisture measurement 
option to promote direct measurement and use of lumber moisture content 
monitoring as a kiln control parameter during high-temperature drying 
(i.e., in kilns operating above the dry bulb temperature set points 
under the work practice temperature option). An example of an in-kiln 
direct lumber moisture measurement technique is use of 2 steel plates 
inserted into packages of lumber spatially distributed throughout the 
kiln. The electrical resistance between the plates is measured and 
relayed to a moisture meter which supplies moisture measurements to the 
kiln control software. We are proposing that at least 1 lumber moisture 
reading per 20,000 board feet (BF) of lumber in the kiln load be taken 
and that the batch average lumber moisture content be determined at the 
end of the batch cycle (when the lumber has reached its lowest kiln-
dried moisture content). The requirement for 1 lumber moisture reading 
per 20,000 BF (which is the same as 20 thousand board feet (20 MBF)) is 
proposed to ensure that there are multiple moisture measurements in 
different areas of the kiln, with the number of lumber moisture 
monitors being scaled to kiln capacity. For example, a lumber kiln 
drying 160 MBF per batch would require at least 8 lumber moisture 
monitors to be distributed throughout the kiln load. For CDKs, we are 
proposing that facilities measure the lumber moisture content at the 
completion of drying for each package of lumber (when the lumber has 
reached its lowest kiln-dried moisture content). Because different 
lumber grades can be produced in a given lumber kiln at different 
times, we are proposing that a ratio of measured lumber moisture 
divided by the minimum kiln-dried lumber moisture limit be developed 
for each batch kiln load and for each package of lumber dried in a CDK. 
If the semiannual average of all the ratios is greater than or equal to 
1 for the kiln, then compliance would be demonstrated. The semiannual 
average ratio of measured moisture divided by the minimum kiln-dried 
lumber moisture limit would be reported in the semiannual report. A 
semiannual averaging time is proposed to correspond with the semiannual 
reporting frequency already required for reporting under the PCWP 
NESHAP, and because a semiannual average provides flexibility for the 
variability associated with drying lumber of different dimensions cut 
from logs with naturally occurring initial moisture variations (e.g., 
seasonal or tree stand variations). See proposed 40 CFR 
63.2241(e)(3)(ii) and 40 CFR 63.2270(i) for more details on the 
proposed methodology for calculating the semiannual average from kiln-
dried lumber moisture measurements.
    Under the site-specific plan option, facilities would develop and 
operate according to a site-specific plan to minimize lumber over-
drying through temperature and lumber moisture monitoring. The site-
specific plan would be required to be submitted to the delegated 
authority for approval. The site-specific limits from the plan would 
then have to be incorporated into the facility's operating permit when 
it is next reopened or renewed, as applicable.
    The site-specific plan would be required to: identify one 
temperature parameter (such as wet or dry bulb temperature, wet bulb 
depression, or temperature drop across the load) to be continuously 
monitored during the kiln drying cycle; include a description of how 
the temperature parameter is measured and used to minimize over-drying 
of lumber; and include a site-specific limit for the temperature 
parameter that minimizes over-drying. Facilities would be required to 
continuously monitor the temperature parameter no less often than every 
15 minutes and calculate the 3-hour block average for comparison to the 
site-specific temperature limit. See proposed 40 CFR 63.2269(a)-(b) and 
40 CFR 63.2270(h) for more details on temperature monitoring under the 
PCWP NESHAP.
    In addition, the site-specific plan would be required to: include a 
site-specific method for monitoring kiln-dried lumber moisture content 
(weight percent, dry basis); specify the location of such monitoring 
within the lumber manufacturing process (for example, at the kiln 
unloading track, in lumber storage, or at the planer); specify the 
minimum kiln-dried lumber moisture content limit based on the lumber 
moisture grades produced at the facility based on 40 CFR 
63.2241(e)(3)(iii) and table 11 to subpart DDDD of 40 CFR part 63; and 
adhere to a minimum data requirement of one moisture measurement per 
20,000 BF. Facilities would be required to calculate and record the 
monthly average kiln-dried lumber moisture content, compare the monthly 
average to the minimum kiln-dried lumber moisture content limit, and 
take corrective action if the monthly average lumber moisture content 
is below the minimum limit. Facilities would be required to maintain 
records of corrective actions taken and report corrective actions in 
the semiannual report. In addition, facilities would be required to 
calculate the semiannual average of batch or continuous kiln lumber 
moisture measurements and compare the semiannual average to the minimum 
kiln-dried lumber moisture content limit to determine compliance. The 
monthly averages with records of corrective action (when needed) are 
proposed to provide interim indications of compliance before the 
semiannual average is determined because facilities using a site-
specific plan are likely to be measuring the moisture of kiln-dried 
lumber downstream of the kiln (e.g., at the planer).
    The site-specific plan containing limits for temperature and lumber 
moisture content would have to be developed and submitted to the 
delegated authority within 180 days after the effective date of the 
final rule. The written site-specific plan would have to be maintained 
onsite at the facility and would be enforceable upon the compliance 
date specified in the rule. Facilities would be required to report 
deviations from the site-specific plan following the compliance date. 
Once the site-specific plan is approved by the delegated authority, the 
plan requirements would be incorporated into the facility's title V 
operating permit when the permit is next reopened or renewed, as 
applicable.
    Kiln-dried moisture minimum limit. In the fourth and final element 
of the work practice to minimize lumber over-drying, we are proposing 
minimum limits of kiln-dried lumber moisture content (weight percent on 
a dry basis) that are considered to be over-dried lumber for purposes 
of the PCWP NESHAP. In proposed 40 CFR 63.6241(e)(4) and proposed table 
11 to subpart DDDD of 40 CFR part 63, the ``maximum lumber moisture 
grade'' means the upper limit of lumber moisture content (weight 
percent on a dry basis) that meets the relevant lumber grade standard 
for a lumber

[[Page 31871]]

product. The proposed minimum limit of kiln-dried lumber moisture 
content varies according to the maximum lumber moisture grade as shown 
in proposed table 11 to subpart DDDD of 40 CFR part 63. The minimum 
limits of kiln-dried lumber moisture content proposed acknowledge the 
fact that different lumber moisture grades are produced and that enough 
margin is needed to encompass the target lumber moisture (which is a 
few percent below the grade moisture to ensure the lumber meets grade) 
and allow for variability that occurs around the target moisture. The 
minimum limits of lumber moisture proposed in table 11 to subpart DDDD 
of 40 CFR part 63 reflect the following moistures (all on a weight 
percent, dry basis):
     For lumber with maximum lumber moisture grade above 22 
percent, the proposed minimum limit below which lumber is considered 
over-dried is 15 percent moisture. A minimum limit of 15 percent 
moisture was selected because a limit of 15 percent lumber moisture is 
included in at least 1 air permit for a lumber facility producing 
moisture grades higher than KD-19.
     For lumber with a maximum lumber moisture grade of 19 to 
21 percent, the proposed minimum limit below which lumber is considered 
over-dried is 12 percent moisture. A minimum limit of 12 percent was 
selected because this limit is consistent with the limit indicated in 
several air permits for facilities producing KD-19, which is a grade 
produced in high volume.
     Consistent with the 7 percent difference between KD-19 and 
a 12 percent minimum limit, we are proposing the maximum grade moisture 
minus 7 percent as the minimum kiln-dried lumber moisture limit for 
grades with 18 down to 12 percent maximum moisture content (e.g., 12 
percent grade-7 percent = 5 percent minimum kiln-dried lumber moisture 
limit).
     For lumber with maximum lumber moisture grade less than or 
equal to 10 percent, as required for some products to be exported, the 
proposed minimum limit below which lumber is considered over-dried is 
half the maximum lumber moisture grade. A 5 percent minimum kiln-dried 
lumber moisture limit is proposed for lumber with a maximum moisture 
grade of 11 percent, consistent with the minimum limit of 5 percent for 
grades of 10 and 12 percent moisture.
    We estimate the HAP emission reduction achieved by the work 
practice to be 488 tpy for existing sources. We estimate that the work 
practice would also reduce 6,700 tpy of VOC emissions (as WPP1 \11\) 
from existing sources. For new sources, we estimate that the work 
practice would result in emission reductions of 77 tpy HAP and 1,000 
tpy VOC (as WPP1).
---------------------------------------------------------------------------

    \11\ VOC as WPP1 is based on the wood products protocol in which 
VOC emissions as propane are corrected for oxygenated compounds that 
have a low response to the flame ionization detector used to measure 
hydrocarbons, by adding formaldehyde and 35 percent of methanol 
emitted. WPP1 VOC was used in the assessment of lumber kiln 
emissions consistent with the approach used by permitting 
authorities.
---------------------------------------------------------------------------

4. Consideration of Add-On Controls
    The EPA has not identified any lumber kilns with add-on air 
pollution controls. The EPA, as well as state permitting authorities, 
have evaluated the possibility of capturing and controlling emissions 
from lumber kilns and in each case concluded that capture and control 
of lumber kiln emissions is not technically feasible or cost effective 
for VOC emissions from batch or continuous kilns. The technologies 
considered and rejected as technically infeasible in BACT 
determinations include oxidizers (RTO and RCO), carbon adsorption, 
condensation, biofilters, and wet scrubbers (also known as absorbers). 
In some BACT determinations, it was noted that if an RTO were to be 
attempted for use on a lumber kiln, duct heaters and a WESP would 
likely also be needed to prevent resin buildup in the ductwork (for 
safety) as well as to protect the thermal media in an RTO or catalytic 
media in an RCO. Technologies rejected based on technical infeasibility 
for control of VOC are also infeasible for control of HAP in the same 
exhaust stream. Therefore, we do not consider add-on controls for 
lumber kilns to be a viable option for reducing HAP emissions. No 
emission reduction measures more stringent than the proposed work 
practice were identified.

C. What MACT standards are we proposing for process units with organic 
HAP emissions?

    The EPA is proposing MACT standards to resolve unregulated HAP 
emissions from process units that had ``no control'' MACT 
determinations in the 2004 NESHAP that were remanded and vacated. In 
addition to MACT standards for lumber kilns, the EPA is proposing MACT 
standards for various process units in the PCWP source category, 
including various RMH process units, atmospheric refiners, stand-alone 
digesters, fiber washers, fiberboard mat dryers at existing sources, 
hardboard press predryers at existing sources, and log vats. Some of 
these process units are already subject to new source HAP standards in 
the 2004 PCWP NESHAP, including fiberboard mat dryers, hardboard press 
predryers, and reconstituted wood products board coolers (which are a 
type of RMH unit) at new and reconstructed sources. Mixed PCWP process 
streams routed to HAP control devices subject to the current HAP 
emission limits in table 1B to subpart DDDD of 40 CFR part 63 are also 
already subject to the 2004 PCWP NESHAP. This section of the preamble 
describes the MACT standards we are proposing for emissions streams 
with unregulated HAP emissions. A detailed description of the process 
units being regulated and supporting information for the proposed 
standards are provided in the memorandum, Development of Emission 
Standards for Remanded Process Units Under the Plywood and Composite 
Wood Products NESHAP, in the docket for this action.
1. Resinated Material Handling (RMH) Process Units
    The PCWP affected source is the collection of process units used to 
produce PCWP at a PCWP manufacturing facility, including various dryers 
and reconstituted wood products presses which are already subject to 
emission standards under the PCWP NESHAP and other process units for 
which prior ``no control'' MACT determinations were vacated and 
remanded to EPA. Many of the process units with the prior ``no 
control'' MACT determinations are RMH process units within the PCWP 
affected source, including resin tanks, softwood and hardwood plywood 
presses, engineered wood products presses and curing chambers, 
blenders, formers, finishing saws, finishing sanders, panel trim 
chippers, reconstituted wood products board coolers (at existing 
affected sources), hardboard humidifiers, and wastewater operations. 
These process units handle resin or resinated wood material downstream 
of the point in the PCWP process where resin is applied.
    The RMH process units are not designed and constructed in a way 
that allows for HAP emissions capture or measurement. It is not 
feasible to prescribe or enforce an emission standard for control of 
HAP from RMH process units. The RMH process units are equipment within 
the PCWP production building (or outdoor wastewater operations) without 
any enclosure, conveyance, or distinct HAP emissions stream that can 
feasibly be emitted though a conveyance. For example, dry formers, 
saws, and sanders have pick-up points for removal of wood material as 
it is trimmed, but the

[[Page 31872]]

entire process unit is not enclosed or isolated; engineered wood 
products presses are too large to enclose; plywood presses cannot be 
enclosed for operator safety reasons; and board coolers at existing 
sources cannot be enclosed for equipment functionality reasons. 
Emissions from RMH process units are fugitive in nature such that 
application of emissions measurement methodology is not technically 
feasible. Further, emissions capture and measurement from hundreds of 
individual RMH process units would not be economically feasible (e.g., 
with testing costs estimated to exceed $20 million nationwide assuming 
that facilities could capture emissions). For these reasons, it is not 
feasible to prescribe or enforce an emission standard for RMH process 
units. Therefore, the EPA is proposing work practice standards under 
CAA section 112(h).
    To develop work practice standards under CAA section 112(h), 
consistent with CAA section 112(d), measures used by the best 
performing sources to reduce or eliminate emissions of HAP through 
process changes or substitution of materials were considered. This 
approach is consistent with CAA section 112(d)(2)(A). The potential for 
HAP emissions from RMH process units relates to the material being 
processed (i.e., resin and wood). Standards for RMH units pertaining to 
resin-related and wood-related emissions are discussed in the following 
subsections.
a. Resin-Related Emissions From RMH Process Units
    Most PCWP resins are amino/phenolic resins such as phenol 
formaldehyde (PF), melamine urea formaldehyde (MUF), urea formaldehyde 
(UF) with urea scavenger, melamine formaldehyde (MF), or phenol 
resorcinol formaldehyde (PRF). Isocyanates such as MDI are also used. 
The HAP associated with use of amino/phenolic resins at PCWP facilities 
include formaldehyde (CAS 50-00-0), phenol (CAS 108-95-2) and methanol 
(CAS 67-56-1). The HAP associated with MDI resin is 4,4'-
Methylenediphenyl Diisocyanate (CAS 101-68-8). Some PCWP products can 
only be made with specific types or formulations of resins. Other 
products are made with 1 or more types of resins (e.g., OSB can be made 
with PF, MDI, or PF and MDI in the same board). The PCWP resins 
typically are a liquid with high solids content (e.g., up to 70 percent 
solids) as received or may be delivered and applied in powdered form.
    The potential for resin-related HAP emissions from RMH process 
units relates to the free HAP content and volatility of the resin 
system used. The PCWP resin systems used typically have very low free 
HAP content (weight percent) or low vapor pressure depending on the 
resin type and application. For example, most types of amino/phenolic 
resins are non-HAP resins which can be defined as a resin with HAP 
contents below 0.1 percent by mass for Occupational Safety and Health 
Administration-defined carcinogens as specified in section A.6.4 of 
appendix A to 29 CFR 1910.1200, and below 1.0 percent by mass for other 
HAP compounds.
    However, some amino/phenolic resin formulations essential to 
manufacturing dry-process hardboard or I-joists have slightly higher 
weight percentages of some HAP than non-HAP resins but have low vapor 
pressure which reduces the potential for HAP emissions from RMH process 
units at facilities used to make those products. Similarly, MDI resins 
would not be considered non-HAP resins due to their percentage by 
weight MDI content, but MDI resins have very low vapor pressure as 
received and used in RMH process units. In developing work practice 
standards for RMH units, it is necessary to limit resin-related HAP 
emissions without precluding the types of PCWP products covered under 
the PCWP NESHAP from being produced. A work practice standard with 
enforceable options to use a non-HAP resin system or meet a vapor 
pressure limit adheres to the CAA while allowing the different types of 
PCWP products covered under the PCWP NESHAP to be produced.
    Information on resin HAP content (HAP percent, by weight) and resin 
vapor pressure (in kilopascals [kPa] or pounds per square inch absolute 
[psia]) is often available in safety data sheets (SDS) or other 
technical documentation accompanying the resin when it is received from 
the resin supplier. Some PCWP manufacturers may dilute amino/phenolic 
resins when preparing them for use, which would reduce the mass 
fraction of free HAP content or corresponding vapor pressure of the 
free HAP in the resin. Therefore, resin supplier information for the 
``as received'' resin, before the resin is diluted or mixed with wood, 
is the most consistently available source of information to use as the 
basis of the work practice standards pertaining to resin-related HAP.
    When received, PCWP resins are stored in fixed roof resin tanks at 
the PCWP facility at ambient temperature. Resin tanks are the first 
type of RMH process units in which resins are used in the PCWP process. 
The average-size resin tank in the PCWP industry is 12,500 gallons 
while the maximum is 47,000 gallons. Limited vapor pressure data are 
currently available to the EPA for resins used at PCWP facilities. 
Therefore, vapor pressure criteria in the Amino/Phenolic Resin NESHAP 
(40 CFR part 63, subpart OOO) were reviewed in addition to information 
available from PCWP facilities. The maximum true vapor pressure limits 
for applying controls for storage vessels storing liquids containing 
HAP under the Amino/Phenolic Resin NESHAP are 13.1 kPa (1.9 psia) for 
tanks with 20,000 to 40,000 gallon capacity and 5.2 kPa (0.75 psia) for 
storage vessels with 40,000 to 90,000 gallon capacity. A maximum true 
vapor pressure limit of 5.2 kPa (0.75 psia) corresponding with the 
largest PCWP resin tanks is proposed as the vapor pressure work 
practice option for PCWP resin-related HAP emissions. This vapor 
pressure limit would apply for amino/phenolic resins that are not non-
HAP resins as well as for MDI resins. For the PCWP NESHAP, the maximum 
true vapor pressure of the resin as received would be defined in 40 CFR 
63.2292 as the equilibrium partial pressure exerted by HAP in the 
stored liquid at the temperature equal to the highest calendar-month 
average of the liquid storage temperature for liquids stored above or 
below the ambient temperature, or at the local maximum monthly average 
temperature as reported by the National Weather Service for liquids 
stored at the ambient temperature, as determined: (1) from safety data 
sheets or other technical information provided by the PCWP resin 
supplier; or (2) standard reference texts; or (3) by the ASTM Method 
D2879-18 (which is proposed to be incorporated by reference in Sec.  
63.14); or (4) any other method approved by the Administrator.
b. Wood-Related Emissions From RMH Process Units
    The potential for wood-related organic HAP emissions from RMH 
process units is reduced when the wood is purchased pre-dried or is 
dried in a dryer upstream from the RMH process units. Organic HAP in 
wood is released during the drying process (i.e., prior to the RMH 
process units) and dryers are controlled to meet the emission limits 
established in the 2004 PCWP NESHAP. Most RMH process units after the 
drying process are not heated, which further limits the potential for 
wood-related organic HAP emissions. Even if the RMH process unit is 
heated (such as

[[Page 31873]]

plywood or engineered wood product presses), if the wood processed has 
been previously dried then the potential for wood-related HAP emissions 
is reduced because dryers operate at higher temperatures than presses. 
A standard that requires processing of dried wood will minimize wood-
related organic HAP emissions from RMH process units in the affected 
source.
c. RMH Process Unit Proposed Standards
    We are proposing work practice standards to require new and 
existing facilities with RMH process units to (i) use only a non-HAP 
resin (defined in 40 CFR 63.2292), or (ii) use a resin with a maximum 
true vapor pressure of less than or equal to 5.2 kPa (0.75 psia) as 
defined in 40 CFR 63.2292, or (iii) use a combination of resins meeting 
either (i) or (ii). Facilities with RMH process units would also be 
required to process wood material that was purchased pre-dried to a 
moisture content of no more than 30 percent (weight percent, dry basis) 
or that has been dried in a dryer located at the PCWP facility. This 
requirement to process dried wood would not apply for wet formers and 
wastewater operations.
    No options more stringent than the RMH process unit work practices 
were identified for resin tanks, softwood and hardwood plywood presses, 
engineered wood products presses and curing chambers, blenders, 
formers, finishing saws, finishing sanders, panel trim chippers, or 
hardboard humidifiers at new or existing affected sources, or for 
reconstituted wood products board coolers at existing affected sources. 
Reconstituted wood products board coolers at new affected sources are 
already subject to standards under the PCWP NESHAP. For wastewater 
operations, the EPA is proposing a work practice in addition to the RMH 
process unit standards to further limit the potential for HAP 
emissions. Facilities with wastewater operations would be required to 
implement one of the following measures:
     Follow the plan required in 40 CFR 63.2268 for wet control 
devices used as the sole means of reducing HAP emissions from PCWP 
process units; or
     Reduce the volume of wastewater to be processed by reusing 
or recirculating wastewater in the PCWP process or air pollution 
control system; or
     Store wastewater in a closed system; or
     Treat the wastewater by using an onsite biological 
treatment system, or by routing the wastewater to an offsite POTW or 
industrial wastewater treatment facility.

The applicability of these work practices for wastewater operations 
depends on the type of PCWP produced and specific equipment generating 
wastewater. Requiring one of the above work practices in addition to 
the RMH standards was identified as a more stringent option.
    The emissions reductions associated with the work practices for RMH 
units are estimated to be 6.7 tpy of HAP from existing sources. No HAP 
reduction is estimated for new sources projected in the next 5 years 
because all facilities are expected meet the standards upon startup. No 
quantifiable HAP reductions are expected from the additional work 
practice for wastewater operations.
2. Atmospheric Refiners
    Atmospheric refiners operate with continuous infeed and outfeed of 
wood material and under atmospheric pressure for refining (rubbing, 
grinding, or milling) wood material into fibers or particles used in 
particleboard or dry formed hardboard production. Atmospheric refiners 
are further characterized based on their placement before or after 
dryers in the PCWP production process. We are proposing the following 
definitions for inclusion in the PCWP NESHAP to distinguish between the 
2 types of atmospheric refiners.
    Dried wood atmospheric refiner means an atmospheric refiner used to 
process wood that has been dried onsite in a dryer at the PCWP affected 
facility for use in PCWP in which no more than 10 percent (by weight) 
of the atmospheric refiner annual throughput has not been previously 
dried onsite.
    Green wood atmospheric refiner means an atmospheric refiner used to 
process wood for use in PCWP before it has been dried onsite in a dryer 
at the PCWP affected facility. Green wood atmospheric refiners include 
atmospheric refiners that process mixtures of wood not previously dried 
onsite (e.g., green wood) and wood previously dried onsite (e.g., board 
trim) in which wood not previously dried onsite comprises more than 10 
percent (by weight) of the atmospheric refiner annual throughput.
    The above definitions include a 10 percent (by weight) criteria to 
provide clarity for atmospheric refiners that process material recycled 
from various points in the PCWP process. An atmospheric refiner 
``system'' may comprise 1 or more atmospheric refiners with the same 
emission point (e.g., 2 particleboard refiners venting to the same 
baghouse).
a. Dried Wood Atmospheric Refiners
    Based on available information from the 2017 ICR and more recent 
updates, there are 6 dried wood atmospheric refiner systems following 
PCWP dryers. Each of the 6 dried wood atmospheric refiner systems is 
controlled by a baghouse for dust collection. Emissions data for total 
HAP are available from the 2022 CAA section 114 survey testing for 2 of 
the dried wood atmospheric refiner systems. Because there are fewer 
than 30 systems, the MACT floor for existing sources is based on the 
average of the top 5 systems, or in this case the 2 systems with 
available total HAP emissions data. The MACT floor for new sources is 
based on the single best performing system. The MACT floor UPLs for 
existing and new systems were calculated according to the methodology 
referenced in section III.B of this preamble. Based on these 
calculations, the total HAP MACT floor for existing dried wood 
atmospheric refiners following dryers is 4.1E-03 lb/ODT. The total HAP 
MACT floor for new sources is 3.3E-03 lb/ODT.
    Based on the average performance level for dried wood atmospheric 
refiners, we anticipate that the existing and new source total HAP MACT 
floors could be met without the use of add-on HAP controls. No HAP 
reduction is estimated for existing sources. No new dried wood 
atmospheric refiners are projected to be constructed or reconstructed 
in the next 5 years.
    The EPA considered an option more stringent than the MACT floor to 
require dried wood atmospheric refiners to meet the emission limits in 
table 1B to subpart DDDD of 40 CFR part 63 based on add-on HAP control. 
With this beyond-the-floor option, nationwide emissions reductions for 
existing sources were estimated to be 0.9 tpy of HAP reduced and 28 tpy 
of VOC reduced. The nationwide capital and annual costs of this beyond-
the-floor option are $19 million and $7.8 million per year, with a cost 
effectiveness of $8.4 million per ton of HAP reduced and $284,000 per 
ton of VOC reduced. Energy impacts associated with the beyond-the-floor 
option for existing sources include 24,000 MW-hr/year electricity use 
(with associated secondary air emission impacts) and 475,000 MMBtu/yr 
in natural gas usage. In addition, an estimated 192,000 gal/year of 
wastewater (for RTO washouts) and 113 tons/year of solid waste are 
estimated to be generated.
    After considering the regulatory options for dried wood atmospheric 
refiners, the EPA is proposing MACT standards based on the MACT floor 
for

[[Page 31874]]

existing and new dried wood atmospheric refiners. The more stringent 
beyond-the-floor option was rejected due to the high costs relative to 
the emission reductions that would be achieved, energy usage, and other 
non-air quality environmental impacts. Although the more stringent 
beyond-the-floor option is not being proposed, we are proposing to 
include a provision in 40 CFR 63.2240(d)(6) to give facilities the 
option of complying with the more stringent limits in table 1B to 
subpart DDDD of 40 CFR part 63 in place of the proposed limits in table 
1C to subpart DDDD of 40 CFR part 63 if they choose to meet the more 
stringent option.
b. Green Wood Atmospheric Refiners
    Existing sources. Based on available information, there are 28 
green wood atmospheric refiner systems that precede dryers in the PCWP 
process. Controls used on green wood atmospheric refiners include 
cyclones, baghouses, and oxidizers used to control or co-control 
dryers. Total HAP emissions data are available from the 2022 CAA 
section 114 survey testing for 5 green wood atmospheric refiner 
systems, including 3 systems with oxidizers \12\ and 2 systems with 
baghouses. The 3 systems with oxidizers are co-controlled with other 
PCWP process units (e.g., dryers, presses) but had measurable emission 
streams at the inlet to the HAP control device containing only 
emissions from the green wood atmospheric refiners. Because the green 
wood atmospheric refiner emissions could be determined at the control 
device inlet, the green wood atmospheric refiner emissions at the 
control device outlet could be estimated. (Estimation of the outlet HAP 
emission rate attributable to the green wood atmospheric refiners was 
necessary because the measured HAP emission rate at the control device 
outlet exceeded the atmospheric refiner inlet emissions, due to the 
greater contribution to the total emissions from co-controlled dryers 
and/or presses.) Based on the emission reduction required for green 
rotary dryers in table 1B to subpart DDDD of 40 CFR part 63, we 
estimated that the green wood atmospheric refiner emissions at the HAP 
control outlet would be 90 percent below the inlet for each run for 
purposes of obtaining run values for use in the MACT floor UPL 
calculation. Using the outlet test run data for the 5 systems, the 
total HAP MACT floor UPL for existing source green wood atmospheric 
refiners is 1.2E-01 lb/ODT.
---------------------------------------------------------------------------

    \12\ A fourth green wood refiner system with RCO does not have 
isolatable inlet or outlet emissions because it vents straight into 
dryer(s) controlled by the RCO.
---------------------------------------------------------------------------

    Based on the average performance level for green wood atmospheric 
refiners, we expect that existing sources would meet the total HAP MACT 
floor. An option more stringent than the MACT floor would be to require 
existing green wood atmospheric refiners to meet the emission limits in 
table 1B to subpart DDDD of 40 CFR part 63. This alternative could be 
considered as a beyond-the-floor regulatory option for all green wood 
atmospheric refiners and allowed as an option for those units already 
co-controlled with dryers meeting the table 1B limits.
    Nationwide costs of the more stringent beyond-the-floor option for 
existing green wood atmospheric refiners (e.g., RTO control) were 
estimated to be $56 million capital and $23 million per year, with 
nationwide reductions of 59 tpy HAP and 834 tpy VOC, and cost 
effectiveness of $388,000/ton HAP reduction and $27,000/ton VOC 
reduced. Energy impacts associated with the beyond-the-floor option for 
existing sources include 64,000 MW-hr/year electricity use (with 
associated secondary air emission impacts) and 1,100 billion Btu/yr in 
natural gas usage. In addition, an estimated 768,000 gal/year of 
wastewater and 300 tons/year of solid waste are estimated be generated.
    The EPA is proposing that MACT for existing source green wood 
atmospheric refiners be based on the MACT floor. The EPA is proposing 
to reject the more stringent beyond-the-floor option (table 1B limits) 
due to high costs compared to the emissions reductions that could be 
achieved, energy usage, and other non-air quality environmental 
impacts. Although the more-stringent beyond the floor option is not 
being proposed, we are proposing to include a provision in 40 CFR 
63.2240(d)(6) to give facilities the option of complying with the more 
stringent limits in table 1B to subpart DDDD of 40 CFR part 63 in place 
of the proposed limits in table 1C to subpart DDDD of 40 CFR part 63 if 
they choose to meet the more-stringent option.
    New sources. The total HAP MACT floor for green wood atmospheric 
refiners at new sources, based on the UPL of the data set for the 
single best performing system, is 2.4E-03 lb/ODT. We note that this UPL 
calculation is based on a limited data set.\13\ Comparing the MACT 
floor to the average performance level achieved by all of the green 
wood atmospheric refiners suggests that add-on HAP control (e.g., 
oxidizer) would be needed by most systems to meet the MACT floor for 
new sources. The same level of HAP control (e.g., oxidizer) would be 
achieved by new source green wood atmospheric refiners that are co-
controlled with process units required to meet the emission limits in 
table 1B to subpart DDDD of 40 CFR part 63. Therefore, we are proposing 
to provide the option in 40 CFR 63.2240(d)(6) that would allow green 
wood atmospheric refiners to meet either the new source MACT floor UPL 
specific to green wood atmospheric refiners or the current table 1B 
limits, because either limit would result in the same level of HAP 
control (e.g., that achieved by use of an oxidizer). Emission 
reductions were estimated to be 4.9 tpy organic HAP and 77 tpy VOC. No 
options more stringent than the MACT floor were identified. Therefore, 
we are proposing standards for new source green wood atmospheric 
refiners based on the MACT floor.
---------------------------------------------------------------------------

    \13\ See the memorandum, Approach for Applying the Upper 
Prediction Limit to Limited Datasets, in the docket for this action 
for details on our review of the data sets and conclusions regarding 
appropriateness of the proposed MACT floors.
---------------------------------------------------------------------------

3. Stand-Alone Digesters and Fiber Washers
    One wet/dry process hardboard facility operates a batch stand-alone 
digester and a fiber washer that have unregulated HAP emissions. Stand-
alone digesters are used to steam or water soak wood chips so that they 
may be easily rubbed apart or ground into fibers in atmospheric 
refiners that follow the digesters. Stand-alone digesters have batch 
operating cycles that differ from pressurized refiner pre-steaming 
vessels (sometimes called ``digesters'') used to preheat wood chips 
prior to refining. Pressurized refiner pre-steaming vessels have 
continuous infeed and outfeed without pressure release between the pre-
steamer and pressurized refiner. We are proposing to add the following 
definition of ``stand-alone digester'' to the PCWP NESHAP to clearly 
distinguish this type of unit from pressurized refiners, which are 
already subject to the PCWP NESHAP.

    Stand-alone digester means a pressure vessel used to heat and 
soften wood chips (usually by steaming) before the chips are sent to 
a separate process unit for refining into fiber. Stand-alone 
digesters operate in batch cycles that include filling with wood 
chips, pressurization, cooking of wood chips under pressure, 
pressure release (purge) venting, and chip discharge (blow) from the 
pressure vessel. Venting of emissions from stand-alone digesters is 
separate from any downstream refining process. A stand-alone 
digester is a process unit.

Pressurized refiners are already subject to emission standards from the 
2004 PCWP NESHAP. We are proposing to

[[Page 31875]]

amend the current definition of pressurized refiner in the PCWP NESHAP 
to state that: ``Pressurized refiners include pre-steaming vessels that 
operate under pressure to continuously feed and vent through the 
pressurized refiner.'' The amended definition would distinguish between 
pre-steaming vessels that are part of pressurized refiner systems and 
stand-alone digesters.
    One batch stand-alone digester system at a wet/dry hardboard 
process was identified. Measuring emissions from the stand-alone 
digester vents is not feasible because the flow rate from the vents is 
inconsistent and varies widely with the intermittent ``purge'' and 
``blow'' cycles. In addition, entrained water droplets in the high 
moisture stream (composed primarily of steam) can interfere with 
emissions samples. Considering the inability to accurately measure 
emissions and the over 60-year age of the 1 remaining stand-alone 
digester in the PCWP industry where hardboard production has severely 
declined due to economic constraints,\14\ we have concluded that 
application of emissions measurement methodology is not practicable due 
to technological and economic limitations and that a work practice is 
the appropriate format of standard according to CAA section 
112(h)(2)(B). The potential for HAP emissions from stand-alone 
digesters is reduced when: (1) clean steam from the boiler is used for 
the digestion process (as opposed to steam potentially contaminated 
with HAP being reused from another process); and (2) HAP-containing or 
wood pulping chemicals \15\ are not added to the digestion process. 
Thus, we are proposing a work practice requiring clean steam to be used 
in the digesters and prohibiting addition of HAP-containing or wood 
pulping chemicals to the digestion process. Initial and continuous 
compliance with the stand-alone digester work practice is proposed to 
be demonstrated through recordkeeping. No regulatory options more 
stringent than the work practice were identified for further 
consideration for existing or new stand-alone digesters. No new 
fiberboard or hardboard mills are projected; therefore, no new PCWP 
affected sources are expected to use stand-alone digesters.
---------------------------------------------------------------------------

    \14\ Eighteen facilities manufacturing hardboard were in 
operation when the PCWP NESHAP was promulgated in 2004. Four 
hardboard manufacturing facilities remain in operation today.
    \15\ Wood pulping chemicals added to dissolve lignin in wood 
include sodium sulfide (Na2S) in combination with sodium 
hydroxide (NaOH), sulfurous acid (H2SO3) 
compounds, or sodium sulfite (Na2SO3) in 
combination with sodium carbonate (Na2CO3). 
Lignin removal is not necessary in the hardboard industry where 
natural lignin helps bind wood fibers in processes where synthetic 
resins are not used.
---------------------------------------------------------------------------

    Fiber washers are units in which water-soluble components of wood 
(hemicellulose and sugars) that have been produced during digesting and 
refining are removed from the wood fiber before the fiber is used in 
fiberboard or hardboard production. In a fiber washer, wet fiber 
leaving a refiner is further diluted with water and then passed over a 
filter, leaving the cleaned fiber on the surface. With the decline in 
the number of wet process fiberboard and hardboard facilities since the 
2004 NESHAP was promulgated, only 1 fiber washer remains in operation 
in the PCWP industry. This vacuum drum-type washer is over 60 years old 
(due to economic constraints), is uncontrolled, and is not configured 
with an enclosure to capture emissions for measurement. Because there 
are technological and economic limitations to measuring emissions from 
this washer, this unit meets the criteria under CAA section 
112(h)(2)(B) for establishing a work practice standard. The potential 
for HAP emissions from the fiber washer is already reduced because the 
facility uses fresh water to perform washing (as opposed to reusing 
process water) and does not use any wood pulping chemicals to dissolve 
lignin or HAP-containing chemicals (such as resins) in the 
manufacturing process. The lignin that remains in the fiber helps bind 
the wood fibers together to form the hardboard product. We are 
proposing a work practice for PCWP fiber washers to use fresh water for 
washing and processing fiber without addition of wood pulping or HAP-
containing chemicals. Initial and continuous compliance with the fiber 
washer work practice is proposed to be demonstrated through 
recordkeeping. No regulatory options more stringent than the work 
practice were identified for further consideration for existing or new 
fiber washers. No new fiberboard or hardboard mills are projected; 
therefore, no new PCWP affected sources are expected to use fiber 
washers. No HAP emission reductions are expected to result from the 
work practices standards because they are already in use.
4. Fiberboard Mat Dryers and Press Predryers at Existing Sources
    Fiberboard mat dryers are conveyor-type dryers used to dry wet-
formed fiber mats. Press predryers are used in the wet/dry hardboard 
process to remove additional moisture from the hardboard mat after it 
exits the fiberboard mat dryer before the mat enters the hardboard 
press.
    The PCWP NESHAP contains HAP emission standards for fiberboard mat 
dryers (heated zones) and hardboard press predryers at new sources 
(i.e., the add-on control device compliance options in table 1B to 
subpart DDDD of 40 CFR part 63 or the production-based compliance 
option in table 1A to subpart DDDD of 40 CFR part 63). In this action, 
the EPA is proposing standards for the heated zones of an existing 
fiberboard mat dryer and hardboard press predryer that are unregulated 
for HAP at a wet/dry process hardboard facility. Both of these existing 
dryers are uncontrolled.
    According to CAA section 112(d)(3)(B), because there are fewer than 
30 sources, the MACT floor for existing sources must be based on the 
``average emission limitation achieved by the best performing 5 
sources'' or in this case the one fiberboard mat dryer and one predryer 
with unregulated HAP emissions. The average emission limitation 
achieved for purposes of setting the MACT floor emission level is based 
on the upper limit (UL) of the test data when there is only 1 source 
(where prediction is not required). The UL for each dryer was 
calculated using HAP test data collected in 2022 through a CAA section 
114 survey.
    For the fiberboard mat dryer (heated zones), the MACT floor based 
on the UL of the test data is 4.9E-02 lb total HAP per MSF on a \1/8\'' 
thickness basis. The MACT floor based on the UL of the test data for 
the press predryer is 8.0E-02 lb total HAP per MSF on a \1/8\'' 
thickness basis. We note that the MACT floor calculations were based on 
limited data sets.\16\ No organic HAP emission reductions are 
associated with the MACT floor options.
---------------------------------------------------------------------------

    \16\ See the memorandum, Approach for Applying the Upper 
Prediction Limit to Limited Datasets, in the docket for this action 
for details on our review of the data sets and conclusions regarding 
appropriateness of the proposed MACT floors.
---------------------------------------------------------------------------

    We considered beyond-the-floor regulatory options for the existing 
fiberboard mat dryer and press predryer, which would be to route the 
dryers to incineration-based control, such as an RTO, in order to meet 
the emission limits of table 1B to subpart DDDD of 40 CFR part 63 as 
required in the NESHAP for new sources. Both dryers were considered 
together because using 1 RTO to treat emission streams from both dryers 
would be more cost-effective than 2 separate HAP control devices. In 
addition to RTO installation and operating costs, compliance costs 
would include emissions testing, RTO temperature monitoring, reporting, 
and recordkeeping. Total capital and annual costs associated with the 
beyond-the-

[[Page 31876]]

floor option are estimated to be $2.2 million and 1.0 million per year, 
respectively. Reductions in HAP and VOC associated with the beyond-the-
floor option for both dryers are estimated to be 8.1 tpy organic HAP 
and 16 tpy VOC, for a cost effectiveness of $117,000/ton of organic HAP 
reduced and $61,000/ton of VOC reduced. Energy impacts associated with 
the beyond-the-floor option for existing sources include 3,000 MW-hr/
year electricity use (with associated secondary air emission impacts) 
and 50,000 MMBtu/yr in natural gas usage. In addition, an estimated 
21,000 gal/year of wastewater and 8.2 tons/year of solid waste are 
estimated to be generated from oxidizer media washouts and 
replacements, respectively.
    After reviewing the regulatory options for the existing fiberboard 
mat dyer heated zones and press predryer, the EPA is proposing to set 
the HAP emission standards at the MACT floor. The more stringent 
beyond-the-floor options for each dryer were rejected because of the 
high costs relative to the HAP emission reduction that could be 
achieved, energy usage, and other non-air quality environmental 
impacts. Although the more stringent beyond-the-floor options are not 
being proposed, we are proposing to include a provision in 40 CFR 
63.2240(d)(6) to allow for compliance with the more stringent limits in 
table 1B to subpart DDDD of 40 CFR part 63 in place of the proposed 
limits in table 1C to subpart DDDD of 40 CFR part 63.
5. Log Vats
    Log vats are used to condition logs before they are cut into veneer 
or wood strands. Hot water vats in which logs are immersed are often 
open to the atmosphere. In log steaming or ``chest'' vats, logs are 
placed in the vat in batches, the door is closed, and steam (which 
condenses in the vat) along with hot water sprays are used to condition 
the logs for a specified time before the logs are removed for veneer 
production. Both types of vats heat logs to within the same temperature 
range (up to 230 [deg]F based on ICR responses).
    The recent ICR identified 81 log vats used at PCWP facilities, 
including 51 hot water vats and 30 chest vats. None of the log vats are 
controlled for HAP, have a conveyance for collection of emissions, or 
have a stack for emissions measurement. Because the log vats have 
neither the proper emissions capture and conveyance ductwork nor stacks 
where emissions testing could be conducted, based on CAA section 
112(h)(2)(A) and (B), we are proposing a work practice standard for log 
vats at existing or new sources. Although the HAP emissions data are 
not available to correlate with log temperature, it is reasonable to 
expect that overheating logs could increase the potential for HAP 
emissions from log vats. The proposed work practice standard would 
require facilities to: (a) operate each vat using a site-specific 
target log temperature that does not exceed 212 [deg]F, measured in the 
water used to soak the logs or in the wood cut at the lathe or 
stranders; and (b) operate each vat to reduce the potential for 
fugitive emissions by either: (1) covering at least 80 percent of the 
vat hot water surface area for soaking vats in which logs are 
submerged; or (2) keeping doors closed while steam or hot water showers 
are being applied inside log steaming vats.
    Initial and continuous compliance with the log vat work practice 
could be demonstrated through monitoring, recordkeeping, and reporting 
that reflects adherence to the work practice conditions. No regulatory 
options more stringent than the work practice were identified for 
further consideration for log vats. Nationwide organic HAP reductions 
are estimated to be 0.7 tpy for existing sources and 0.17 tpy for new 
sources.
6. Mixed PCWP Process Streams Regulated at Existing Sources
    Some PCWP facilities route emission streams from multiple process 
units of the same or different types into 1 shared HAP control system 
such as an RTO, RCO, biofilter, or process incineration system to meet 
the compliance options in table 1B to subpart DDDD of 40 CFR part 63. 
In a few mixed process arrangements, an emissions stream from a 
remanded unit is mixed at the inlet to a HAP control device and co-
controlled with other process units listed in table 1B such that the 
combined emission stream became subject to the table 1B limits when the 
control system was initially installed to meet the 2004 NESHAP or as 
part of the PCWP plant design. Due to commingling, emissions from each 
individual type of process unit contributing to a mixed PCWP process 
stream cannot be distinguished at the inlet or outlet of the control 
device. For this reason, we are proposing that mixed PCWP process 
streams from remanded units meeting the compliance options in table 1B 
be considered a separate type of emission stream that remains subject 
to the table 1B limits. Mixed PCWP process streams are proposed to be 
defined in 40 CFR 63.2292 as an emission stream from a process unit 
subject to the final amendments that was commingled with emissions 
stream(s) from process unit(s) subject to the compliance options in 
table 1B to subpart DDDD of 40 CFR part 63 before the effective date of 
the final amendments at an affected source that commenced construction 
(or reconstruction) on or before the date of this proposal. The 
recommended definition of ``mixed PCWP process stream'' refers 
specifically to a ``stream'' as opposed to a whole process unit because 
there can be uncaptured or uncontrolled emissions from a remanded 
process unit in addition to the captured emission stream from the 
remanded unit that is routed to the HAP control device as part of a 
mixed PCWP process stream.

D. What MACT standards are we proposing for process units with MDI 
emissions?

    The EPA is proposing standards to regulate MDI emissions from 
reconstituted wood products presses, tube dryers that blow-line blend 
MDI resin, and miscellaneous coating operations. The proposed standards 
for tube dryers that blow-line blend MDI resin would apply for 
commingled MDI emissions from tube dryers and reconstituted wood 
products presses using MDI. Supporting information for the proposed 
standards is provided in the memorandum, Regulatory Options for MDI 
Emissions from Plywood and Composite Wood Products Reconstituted Wood 
Products Presses, Tube Dryers, and Miscellaneous Coating Operations, in 
the docket for this action.
1. Reconstituted Wood Products Presses
    The EPA is proposing standards for MDI emissions from reconstituted 
wood products presses that use MDI resin at any time during the year in 
any portion of the board (e.g., whole board, core, or face). Emissions 
data for MDI are available from EPA Method 326 testing conducted in 
2022 (in response to a CAA section 114 request) on presses using MDI 
throughout the whole board.
    The EPA is proposing to distinguish reconstituted wood products 
presses that produce OSB from those producing particleboard or MDF (PB/
MDF) for purposes of establishing MDI standards because product 
differences appear to affect MDI emissions. With the HAP control level 
being the same, product differences are expected to be the reason for 
the difference in MDI emissions. Particleboard and MDF are similar to 
one another in that they are used for the same interior product markets 
(e.g., cabinets, shelving, furniture) while OSB is used for exterior 
applications (e.g., siding, roofing). OSB furnish is made of flat wood 
strands (e.g., several inches in length) as opposed to the small wood

[[Page 31877]]

fibers used to manufacture MDF. The smaller wood fibers (or particles) 
used in MDF/PB presses have greater overall surface area than the much 
larger OSB wood strands per volume of board produced. The difference in 
wood furnish surface area that is coated with MDI resin can result in 
different potential for MDI emissions from PB/MDF presses compared to 
OSB presses. Different pressing temperatures are also used. Therefore, 
we are proposing to group the presses by product type to adequately 
address the variability in MDI emissions associated with different 
products.
    There are 26 OSB presses that use MDI resin. The EPA has MDI 
emissions data for 2 of these presses using the type of control system 
considered to be best performing for reducing organic HAP emissions, 
including MDI. As noted previously, when there are fewer than 30 
sources, the MACT floor is based on the best performing 5 sources. 
However, in this case emissions data are only available for 2 sources 
for determining the MACT floor. Using the MDI emissions data from 2 OSB 
presses, the MACT floor for existing sources was calculated and 
compared to the 3xRDL MDI concentration and OSB press emission rate 
values of 27 micrograms per dry standard cubic meter (ug/dscm) of air 
or 2.5E-04 lb/MSF \3/4\'' (1.3E-04 lb/MSF \3/8\''). The 3xRDL values 
exceeded the MACT floor concentration and emission rate for existing 
sources and are therefore being proposed in place of the existing 
source MACT floor for OSB presses using MDI to ensure that the 
standards are established at the minimum level at which emissions can 
be measured reliably. The MDI MACT floor for new source OSB presses was 
calculated using the MDI emissions data for the best performing OSB 
press and compared to the 3xRDL MDI concentration. The 3xRDL values 
exceeded the MACT floor concentration and emission rate for new sources 
and are therefore being proposed in place of the new source MACT floor 
for OSB presses using MDI.
    There are 10 PB/MDF presses that use MDI resin. The EPA has MDI 
emissions data for 2 of the PB/MDF presses with the type of control 
system considered to be best performing for reducing organic HAP 
emissions, including MDI. Using the MDI emissions data from the 2 PB/
MDF presses, the MACT floor for existing sources was determined to be 
8.4E-04 lb/MSF \3/4\'' or 200 ug/dscm, which is higher than the 
corresponding 3xRDL value. The MACT floor for new source PB/MDF presses 
was calculated based on the single best performing press and compared 
to the 3xRDL MDI concentration and PB/MDF press emission rate values of 
27 ug/dscm and 2.3E-04 lb/MSF \3/4\'', respectively. The 3xRDL values 
exceeded the MACT floor concentration and emission rate and are 
therefore being proposed in place of the MACT floor for new source PB/
MDF presses using MDI to ensure that the standards are established at 
the minimum level at which emissions can be measured reliably.
    Estimated annual emissions of MDI from the reconstituted wood 
products presses tested were less than 0.1 ton/year. This low level of 
emissions is likely because MDI polymerizes into a solid rapidly and 
irreversibly in the reconstituted wood products press, and the presses 
tested are equipped with the types of organic HAP controls found on the 
best performing sources in the PCWP industry. Also, less than one 
hundredth of a percent (<0.01%) of the MDI applied was measured at the 
inlet or outlet of the control device. Considering the low levels of 
MDI emitted and that reconstituted wood products presses already meet 
HAP limits from the 2004 PCWP NESHAP using robust HAP controls, no 
regulatory options more stringent than the existing or new source MACT 
floors for MDI were identified for OSB or PB/MDF reconstituted wood 
products presses. Accordingly, we are proposing that the MDI MACT 
floors for existing and new OSB and PB/MDF reconstituted wood products 
presses is MACT for these process units.
    Reconstituted wood products presses operating HAP controls are 
expected to meet the MACT floor for existing and new sources. However, 
it is currently unknown whether presses at 2 particleboard facilities 
that meet the PCWP production-based compliance option (PBCO) \17\ using 
pollution prevention measures would meet the MDI MACT floor. An MDI 
emission reduction of 0.077 tpy with corresponding VOC reduction of up 
to 63 tpy is estimated for existing sources. For new sources, no MDI or 
VOC emission reductions are estimated because new presses are expected 
to meet the new source limit.
---------------------------------------------------------------------------

    \17\ Table 1A to subpart DDDD of 40 CFR part 63 contains the 
PBCO total HAP limits.
---------------------------------------------------------------------------

2. Tube Dryers
    Primary tube dryers often incorporate blow-line blending in which 
resin is added to wood fibers as they enter the primary tube dryer. The 
resin and wood fibers mix with the turbulent conditions in the primary 
tube dryer as the wood fiber is dried. Within the PCWP industry, 5 
primary tube dryer systems incorporate blow-line blending using MDI 
resin to produce MDF. In addition, 3 secondary tube dryer systems 
follow primary tube dryers that blow-line blend MDI resin. All of the 
primary and secondary tube dryer systems have air pollution controls to 
reduce organic HAP emissions to comply with the 2004 PCWP NESHAP 
standards.
    Primary and secondary tube dryers are often co-controlled. In some 
systems, air flow from the secondary tube dryers vents through the 
primary tube dryers (for energy conservation), while in other systems 
the secondary tube dryers vent directly to the same air pollution 
control system as the primary tube dryers. All of the secondary tube 
dryers that follow primary tube dryers in which MDI is injected with a 
blow-line have emissions that exit from the same emission point as 
primary tube dryers. Therefore, the MDI emission limits developed for 
the primary tube dryers apply for secondary tube dryers as well.
    Primary tube dryers may also be co-controlled with a reconstituted 
wood products press. Emissions data for MDI are available from the 2022 
CAA section 114 survey testing for 1 MDI primary tube dryer system that 
blow-line blends MDI and is co-controlled with a press. Emissions from 
the dryer (including press emissions routed through the dryer) are 
controlled by an RTO. The inlet and outlet of the RTO were tested for 
MDI, in which an average MDI reduction of 87 percent was achieved. The 
inlet MDI concentration for the blow-line blend tube dryer (with press) 
system was higher than MDI emissions from reconstituted wood products 
presses alone, which suggests that most of the MDI emissions in a 
combined system are associated with the blow-line blend tube dryer. 
Therefore, we are proposing that the same MDI standard (in terms of lb/
ODT) established for blow-line blend tube dryers alone would also apply 
for blow-line blend tube dryer and press combinations.
    Because there are fewer than 30 primary tube dryers that blow-line 
blend MDI, according to CAA section 112(d), the MACT floor for existing 
sources is based on the best performing 5 systems for which the 
Administrator has emissions information and the MACT floor for new 
sources is based on the single best performing system. In this case, 
because emissions data are available for only 1 system, data for this 1 
system was used to establish the MACT floor for both existing and new 
sources. Using the emission test run data for the tested dryer system 
(7 runs), the MACT floor for new and existing sources is 1.7E-02 lb/ODT 
or 0.68 mg/

[[Page 31878]]

dscm. No regulatory options more stringent than the MACT floor were 
identified for tube dryers that blow-line blend MDI.
    Because all of the tube dryer systems that blow-line blend MDI 
resin have HAP emission controls, we anticipate that they would all 
meet the MDI MACT floor based on the average MDI emissions from the 
comparable unit tested. No MDI emission reductions are estimated as all 
existing and new sources are expected to meet the MACT floor.
3. Miscellaneous Coatings Operations
    The EPA is proposing to regulate MDI emissions from miscellaneous 
coating operations in which MDI moisture sealants are applied to 
engineered wood products such as parallel strand lumber or LVL. One MDI 
moisture sealant spray booth at an engineered wood products facility 
was identified and tested as part of the 2022 CAA section 114 survey. 
Using the test data from this facility, the proposed MACT floor limit 
for existing and new sources is 1.9E-03 lb MDI emitted/lb sealant 
applied, or 1.4E-05 lb MDI/ft\2\ surface area coated based on coating 
HAP content. No reduction in MDI emissions is estimated as a result of 
the MDI MACT floor. No options more stringent than the MACT floor 
emission level were identified for further analysis.

E. What performance testing, monitoring, and recordkeeping and 
reporting are we proposing?

1. Performance Testing
    For the new and existing source emission limits being added to the 
PCWP NESHAP, we are proposing that new sources demonstrate initial 
compliance within 180 days after the effective date of the final rule 
or after startup, whichever is later, and that existing sources 
demonstrate initial compliance within 3 years after promulgation of the 
final rule. Additionally, we are proposing that subsequent performance 
testing would be required every 5 years (60 months), using the methods 
identified in table 4 to subpart DDDD of 40 CFR part 63.
    The proposed emissions test methods for total HAP include EPA 
Method 320 (40 CFR part 63, appendix A), NCASI Method IM/CAN/WP-99.02 
(IBR in 40 CFR 63.14), NCASI Method ISS/FP-A105.0 (IBR in 40 CFR 
63.14); or ASTM D6348-12e1 (IBR in 40 CFR 63.14) with the conditions 
discussed in section VIII.I of this preamble. EPA Method 326 (40 CFR 
part 63, appendix A) is proposed for MDI emissions measurement, in 
which a minimum sample of 1 dry standard cubic meter (dscm) must be 
collected. For PM as a surrogate to HAP metals, either EPA Method 5 (40 
CFR part 60, appendix A-3) or EPA Method 29 (40 CFR part 60, appendix 
A-8) is proposed with a minimum sample volume of 2 dscm. For Hg, EPA 
Method 29 or EPA Method 30B (40 CFR part 60, appendix A-8) are 
proposed, with a minimum sample volume of 2 dscm. The EPA Method 26A 
(40 CFR part 60, appendix A-8) is proposed for HCl emissions 
measurement with a minimum sample volume of 2 dscm. The recently 
updated EPA Method 23 (40 CFR part 60, appendix A-8) is proposed for 
PAH emission measurement with a minimum sample volume of 3 dscm. 
Consistent with the treatment of non-detect data used to establish the 
emission standards, we are proposing that non-detect data be treated as 
the MDL in test averages used to demonstrate compliance with the 
standards proposed in tables 1C, 1D, or 1E to subpart DDDD of 40 CFR 
part 63.
2. Parameter Monitoring
    Under this proposal, continuous compliance with the standards 
proposed in tables 1C, 1D, or 1E to subpart DDDD of 40 CFR part 63 
would be demonstrated through control device parameter monitoring 
coupled with periodic emissions testing described earlier in this 
preamble. The parametric monitoring already required in table 2 to 
subpart DDDD of 40 CFR part 63 for thermal oxidizers, catalytic 
oxidizers, or biofilters to demonstrate continuous compliance with the 
compliance options in table 1B to subpart DDDD of 40 CFR part 63 would 
also be required to demonstrate ongoing compliance with the standards 
in tables 1C, 1D, or 1E to subpart DDDD of 40 CFR part 63. In addition 
to the parametric monitoring currently specified for thermal oxidizers, 
catalytic oxidizers, or biofilters, we are proposing to add to table 2 
to subpart DDDD of 40 CFR part 63 the following parameter monitoring 
requirements for the types of APCDs that we expect would be used to 
comply with the standards proposed in tables 1D or 1E to subpart DDDD 
of 40 CFR part 63:
     For WESP, monitor and record the secondary electric power 
input and liquid flow rate;
     For dry ESP, monitor and record the secondary electric 
power input or opacity;
     For wet PM scrubbers, monitor and record the liquid flow 
rate and pressure drop;
     For wet acid gas scrubbers, monitor and record the liquid 
flow rate and effluent pH;
     For electrified filter beds, monitor and record the 
ionizer voltage or current and pressure drop; and
     For mechanical collectors (e.g., cyclone or multiclone) or 
other dry control devices, monitor and record opacity.
    The operating limits for these parameters are proposed to be set 
consistent with the existing provisions of 40 CFR 63.2262, as the 
average of the 3 test run averages during the performance test. 
Continuous compliance with the parameters for WESP, dry ESP, wet 
scrubbers, and EFB would be determined by comparing the 3-hour block 
average parameter average to the limit established during the 
performance test.
    Consistent with existing provisions in table 2 to subpart DDDD of 
40 CFR part 63, a source owner choosing to rely on a control device 
other than a thermal oxidizer, catalytic oxidizer, or biofilter used to 
meet a compliance option in table 1C to subpart DDDD of 40 CFR part 63 
would be required to petition the Administrator for site-specific 
operating parameters to be monitored or would have to maintain the 3-
hour block average THC concentration within the limits established 
during the performance test. The source owner of process units that 
meet a compliance option in table 1C, 1D, or 1E to subpart DDDD of 40 
CFR part 63 without using a control device would be required to 
maintain on a daily basis the process unit controlling operating 
parameter(s) within the ranges established during the performance test 
or maintain the 3-hour block average THC concentration within the 
limits established during the performance test.
    For control devices where opacity is used as an operating 
parameter, we are proposing that a continuous opacity monitoring system 
(COMS) would be used and that the 24-hour block average opacity must 
not exceed 10 percent (or the highest hourly average measured during 
the performance test). We are proposing updates to table 10 to subpart 
DDDD of 40 CFR part 63 to indicate provisions pertaining to opacity and 
COMS that apply for subpart DDDD. We are proposing to change the 
following provisions from ``No'' or ``NA'' to ``Yes'' in table 10: 40 
CFR 63.8(c)(5), 63.8(e), 63.9(f), and 63.10(e)(4). We are also 
proposing to note in table 10 that the requirements for opacity 
standards in 40 CFR 63.6(h)(2) through (9) do not apply because the 
opacity is being proposed as an operating limit and not as an emission 
standard.

[[Page 31879]]

    Continuous monitoring requirements associated with the work 
practices proposed in table 3 to subpart DDDD of 40 CFR part 63 include 
combustion unit bypass stack usage monitoring (e.g., temperature or 
bypass damper position), lumber kiln dry bulb temperature monitoring 
(for comparison of the 3-hour block average to the dry bulb set point), 
in-kiln lumber moisture monitoring (for comparison of the semiannual 
average kiln-dried lumber moisture content), or monitoring of lumber 
kiln temperature (with 3-hour block averaging) and lumber moisture 
(with semiannual averaging) for comparison to limits in an approved 
site-specific plan.
    We are also proposing continuous monitoring and recording of 
process unit bypass stack usage at all times while the process units 
are operating, including times when the process unit is undergoing 
startup or shutdown, and during the operating conditions specified in 
40 CFR 63.2250(f)(2) through (4). This requirement is being proposed to 
ensure that reliable data are available to evaluate continuous 
compliance with the PCWP NESHAP requirements.
    Consistent with NESHAP general provisions, a source owner would be 
required to operate and maintain the source, its air pollution control 
equipment, and its monitoring equipment in a manner consistent with 
safety and good air pollution control practices for minimizing 
emissions, to include operating and maintaining equipment in accordance 
with the manufacturer's recommendations. Owners would be required to 
prepare and keep records of calibration and accuracy checks of the 
continuous monitoring system (CMS) to document proper operation and 
maintenance of the monitoring system.
3. Recordkeeping and Reporting
    Under this proposal, and consistent with existing requirements in 
the PCWP NESHAP, a source owner would be required to submit semi-annual 
compliance summary reports which document both compliance with the 
requirements of the PCWP NESHAP and any deviations from compliance with 
any of those requirements. Owners and operators would be required to 
maintain the records specified by 40 CFR 63.10 and, in addition, would 
be required to maintain records of all monitoring data, in accordance 
with the PCWP NESHAP (40 CFR 63.2282).

F. What other actions are we proposing, and what is the rationale for 
those actions?

    In addition to proposing the new standards and monitoring, 
recordkeeping and reporting requirements discussed above, we are 
proposing to revise the PCWP NESHAP to remove obsolete rule language 
including the emissions averaging compliance option, dates, and 
startup/shutdown provisions that are no longer in effect. Removing the 
outdated language from the PCWP NESHAP would streamline the rule and 
make it easier to read. We are also proposing updates and 
clarifications of the electronic reporting requirements. The proposed 
revisions and rationale are presented below.
1. Emissions Averaging
    Emissions averaging was included in the 2004 rule as a compliance 
option for use at existing affected sources. To date, the EPA is only 
aware of one facility that used the emissions averaging compliance 
option, but that facility has ceased PCWP production. We are proposing 
to remove the emissions averaging compliance option because no existing 
facilities are using it, and emissions averaging is not an option for 
new affected facilities. Also, the proposed new emission standards 
discussed in section IV of this preamble further diminish opportunities 
for emissions averaging. Our proposal to remove the emissions averaging 
option would simplify the rule language.
2. Obsolete Dates and Provisions
    On August 13, 2020, the EPA published several amendments to the 
PCWP NESHAP that were effective on August 13, 2020. The amendments 
included removal of references to the SSM exemption in 40 CFR 
63.6(f)(1) and (h)(1) and changes to certain recordkeeping and 
reporting provisions. The compliance dates for the August 13, 2020, 
amendments were August 13, 2020, for affected sources that commenced 
construction or reconstruction after September 19, 2019, or August 31, 
2021, for all other affected sources. Those compliance dates have 
passed.
    The amendments now being proposed would become effective on the 
date of publication of the final rule and would have multiple 
associated compliance dates as discussed in section IV.G of this 
preamble. To reduce confusion as we add future compliance dates to the 
PCWP NESHAP, we are proposing to remove the obsolete dates and 
provisions that are no longer in effect, including:
     In 40 CFR 63.2233(1) through (3), cross-references to 
specific paragraphs needed to implement the August 13, 2020, amendments 
are proposed to be removed and replaced with a reference to the 
proposed 40 CFR 63.2233(e), which provides compliance dates for the 
rule requirements proposed in this action.
     Paragraphs 40 CFR 63.2250(a) through (c) are proposed to 
be removed and reserved because their requirements no longer apply.
     Date language is proposed to be removed in paragraphs 40 
CFR 63.2250(f) and (g), which are paragraphs that replaced the obsolete 
paragraphs 40 CFR 63.2250(a) through (c) in the August 13, 2020, 
amendments.
     Paragraphs 40 CFR 63.2280(b) and (d) contained dates for 
when electronic submittal of initial notifications and performance test 
results became effective. 40 CFR 63.2281(b)(6) contained dates for when 
electronic submittal of semiannual reports became effective. These 
dates have passed, and the electronic reporting requirements are in 
full effect, so we are proposing to remove dates to make the rule 
easier to read.
     The first part of paragraph 40 CFR 63.2281(c)(4) contains 
dates for language that was phased out as well as dates for when 
electronic reporting requirements were phased in. Similarly, 40 CFR 
63.2282(a)(2) contains obsolete dates and language intended to phase 
out some records and phase in other records. Because the dates have now 
passed, we are proposing to remove the obsolete language to simplify 
the rule.
     Row 2 in table 9 to subpart DDDD of 40 CFR part 63 is 
proposed to be removed and reserved because the requirement for an SSM 
report is no longer in effect.
     The August 13, 2020, final rule added a column to table 10 
to subpart DDDD of 40 CFR part 63 to clarify which general provisions 
in subpart A of 40 CFR part 63 applied before and after August 13, 
2021, for existing sources. The now obsolete column pertaining to 
requirements before August 13, 2021, is proposed to be removed.
    Those amendments pertain to SSM provisions that have been removed 
and to reporting provisions that were added on August 13, 2020. For 
clarity, we are retaining date language from the August 13, 2020, final 
rule that specified compliance dates for standards and electronic 
reporting provisions added with that rulemaking. We have also taken 
care to insert compliance date

[[Page 31880]]

language for the new standards proposed in this action (in 40 CFR 
63.2240(d) and (e), tables 1C, 1D, 1E to subpart DDDD of 40 CFR part 
63, 40 CFR 63.2241(d) through (h), and table 3 to subpart DDDD of 40 
CFR part 63) as discussed further in section IV.G of this preamble.
3. Electronic Reporting Updates and Clarifications
    On November 19, 2020, the EPA published a final rule incorporating 
standard electronic reporting language into the general provisions at 
40 CFR 63.9(k). In this action, we are proposing to update the 
electronic reporting language in 40 CFR part 63, subpart DDDD, to refer 
to the provisions in 40 CFR 63.9(k) in addition to other revisions. The 
proposed revisions are as follows:
     We are proposing to require that initial notifications and 
notifications of compliance status be submitted in a user-specified 
format such as portable document format (PDF) in 40 CFR 63.2280(b) and 
(d) instead of 40 CFR 63.2281(h).
     General provisions pertaining to submittal of CBI are 
proposed to be removed from 40 CFR 63.2281(h), (i)(3), and (j)(3).
     In 40 CFR 63.2281(k), we are proposing to replace language 
pertaining to CEDRI outages (which is now in 40 CFR 63.9(k)) with 
additional detailed procedures for submitting CBI in electronic format. 
The update provides an email address that source owners and operators 
can use to electronically mail CBI to the OAQPS CBI Office when 
submitting compliance reports.
     In 40 CFR 63.2281(l), we are proposing to remove the 
provisions related to force majeure claims which are now in 40 CFR 
63.9(k).
     We are proposing to remove the provision in 40 CFR 
63.2283(d) that states that records submitted to CEDRI may be 
maintained in electronic format, because 40 CFR 63.10(b)(1) already 
allows the retention of all records electronically.
     In table 10 to subpart DDDD of 40 CFR part 63, we are 
proposing to indicate that all of the provisions in 40 CFR 63.9(k) 
apply to 40 CFR part 63, subpart DDDD.
    In addition, we are proposing to amend 40 CFR 63.2281(c)(4) to 
clarify the compliance reporting requirements for the work practices in 
table 3 to subpart DDDD of 40 CFR part 63 (rows 6, 7, or 8). We are 
proposing to clarify that the requirement to report the date, time, and 
duration of every instance in which one of the work practices is used 
applies only if that individual work practice is used for more than 100 
hours during the reporting period. The EPA's original intent was for 
the 100-hour reporting threshold to be compared to the semiannual usage 
of each of the 3 work practices individually, not for the total usage 
of all 3 work practices combined. As stated in 40 CFR 63.2281(c)(4), 
when one of the work practices is used for less than 100 hours per 
semiannual reporting period, a summary of the number of instances and 
total amount of time that work practice was used is required to be 
reported. As noted previously, we are also proposing to require 
continuous monitoring and recording of process unit bypass stack usage 
at all times including during the operating conditions specified in 40 
CFR 63.2250(f)(2) through (4) and table 3 to subpart DDDD of 40 CFR 
part 63 (rows 6, 7, or 8) to ensure that reliable data are available to 
evaluate continuous compliance with the PCWP NESHAP requirements.
    Finally, we are placing in the docket a revised draft version of 
the PCWP semiannual reporting template with updates to reflect the 
proposed changes to 40 CFR part 63, subpart DDDD, described throughout 
this preamble.
4. Definitions and Other Amendments
    We are proposing to add several definitions to the PCWP NESHAP to 
define process units with new standards being added to the rule. We are 
also proposing to amend selected existing definitions to ensure that 
the products and process units covered by the PCWP NESHAP are 
adequately described.
5. Issues Raised by Petitioners Following the RTR
    Following publication of the final RTR (85 FR 49434, August 13, 
2020), the EPA received a petition for reconsideration (Petition) from 
Earthjustice on behalf of Greater Birmingham Alliance to Stop 
Pollution, Louisiana Environmental Action Network, and Sierra Club 
(Petitioners). The Petitioners asked the EPA to reconsider certain 
aspects of the August 13, 2020, final technology review and other 
amendments under the authority of CAA section 307(d)(7)(B), arguing 
that the EPA's rationale for four decisions all appeared for the first 
time in the 2020 final rule and response to comments (RTC) document 
accompanying the final rule.\18\ The EPA is proposing changes to the 
PCWP NESHAP to address some of the Petitioners' concerns and is 
inviting public comment on some of the issues raised by the Petitioners 
in their letter to the EPA, which is available in the docket for this 
action.\19\ The four issues are discussed below.
---------------------------------------------------------------------------

    \18\ National Emission Standards for Hazardous Air Pollutants: 
Plywood and Composite Wood Products (40 CFR part 63, subpart DDDD) 
Residual Risk and Technology Review, Final Amendments, Responses to 
Public Comments on September 6, 2019, Proposal. Document ID No. EPA-
HQ-OAR-2016-0243-0244 in the docket for this action.
    \19\ Letter from J. Pew, Earthjustice, to A. Wheeler, EPA. 
Petition for reconsideration of the final action taken at 85 FR 
49434 (August 13, 2020), titled ``National Emission Standards for 
Hazardous Air Pollutants: Plywood and Composite Wood Products 
Residual Risk and Technology Review submitted on behalf of Greater 
Birmingham Alliance to Stop Pollution, Louisiana Environmental 
Action Network, and Sierra Club.'' October 13, 2020.
---------------------------------------------------------------------------

    In the first issue raised, the Petitioners alleged that the EPA 
failed to set limits for unregulated HAPs. Although we do not agree 
that the Petitioners have met their burden under CAA section 
307(d)(7)(B) to show that it was impracticable to raise this objection 
during the public comment period for the proposed 2020 technology 
review, and thereby compel reconsideration of this issue, this action 
contains proposed standards for unregulated HAP in order to respond to 
the 2007 partial remand and vacatur of the 2004 NESHAP and to comport 
with the 2020 LEAN ruling, such that the Petitioners' concern regarding 
this issue will be resolved once this action is finalized.
    In the second and third issues raised by the Petitioners, they 
disagreed with two work practices the EPA finalized on the August 13, 
2020, for safety-related shutdowns and pressurized refiner startup and 
shutdown and objected to what they perceived to be the EPA's changed or 
new rationale for these work practices, claiming that they did not have 
an opportunity to raise their objections during the public comment 
period. The Petitioners disagreed with the EPA's use of CAA section 
112(h) to develop work practice standards for safety-related shutdowns 
and pressurized refiner startup and shutdown events. For safety-related 
shutdowns, the Petitioners took issue with the EPA's rationale that 
facilities cannot capture and convey HAP emissions to a control device 
during these periods for safety reasons (RTC at 89, emphasis added), 
saying that whether emissions can be conveyed to a control device is 
irrelevant under CAA section 112(h)(2)(A). In response to this 
critique, and to ensure that there is a full opportunity for all 
stakeholders to comment on the EPA's rationale for these work 
practices, the EPA requests comment on the relevance of the ability of 
facilities to capture and convey emissions to a control device to CAA

[[Page 31881]]

section 112(h)(2)(A), given that CAA section 112(h)(2)(A) explicates 
CAA section 112(h)(1) which explicitly refers to the EPA's judgment as 
to when it is not feasible to prescribe or enforce an emission standard 
for control of a HAP (emphasis added).
    Regarding the EPA's rationale under CAA section 112(h)(2)(B) for 
the safety-related shutdown and pressurized refiner startup and 
shutdown work practices, the Petitioners expressed discontent with the 
EPA's conclusion that stack tests (which typically take 1 to 3 hours) 
cannot be conducted for events lasting only minutes. The Petitioners 
asserted that EPA should have considered the practicability of other 
measurement methodologies including CEMS or continuous parameter 
monitoring. In response to the Petitioners' concerns, we maintain that 
stack testing is not feasible for safety-related shutdown events 
lasting only minutes or for pressurized refiner startup/shutdown events 
lasting less than 15 minutes. We request comment on how the EPA could 
feasibly prescribe or enforce a numeric emission limit for such short-
term events without the ability to conduct stack testing. Further, 
continuous operation of CEMS on bypass stacks that are unused for the 
majority of process operating time is not practicable from an economic 
standpoint or technically (e.g., because of the calibration drift 
likely to occur while the CEMS goes unused). The source testing 
required for conducting a RATA of CEMS would not be possible without 
requiring the use of the bypass during the RATA. Obtaining emissions 
data to correlate with parameters to establish continuously monitored 
parameter limits also necessitates stack testing. Although CEMS or 
specific continuously monitored parameter limits are not an appropriate 
measurement methodology for safety-related shutdowns and pressurized 
refiner startups and shutdowns themselves because of technical and 
economic limitations, we are proposing additional continuous parameter 
monitoring of bypass stack usage in addition to the work practices for 
safety-related shutdowns and pressurized refiner startup/shutdown 
events to address the Petitioners' concern. As discussed in section 
IV.A.6 of this preamble, we are proposing to require continuous 
monitoring of combustion unit bypass stacks in addition to proposing 
standards for annual tune-ups of combustion units used to direct-fire 
dryers. As discussed in section IV.E.2 of this preamble, we are also 
proposing continuous monitoring of process unit bypass stack usage at 
all times while the process units are operating, including times when 
the process unit is undergoing startup or shutdown, and during safety-
related shutdowns and pressurized refiner startup/shutdown events to 
ensure that reliable data are available to evaluate continuous 
compliance with the PCWP NESHAP requirements.
    The Petitioners also took issue with inclusion of measures that 
facilities have developed to protect workers and equipment in the 
safety-related shutdown work practice. The Petitioners argued that the 
steps an operator takes to protect workers and equipment are not 
necessarily the steps needed to prevent excess emissions or to remove 
raw materials and the heat source from the process as expeditiously as 
possible. We disagree with the Petitioners that the phrase ``to protect 
workers and equipment'' detracts from the safety-related shutdown work 
practice requirements to ensure that the flow of raw materials (such as 
furnish or resin) and fuel or process heat (as applicable) ceases and 
that material is removed from the process unit(s) as expeditiously as 
possible given the system design to reduce air emissions. However, we 
request comment on inclusion of measures facilities developed to 
protect workers and equipment from the safety-related shutdown 
provision. We also request comment on all aspects of the work practice 
provisions (which appear in table 3 to subpart DDDD of 40 CFR part 63, 
rows 6 and 7) based on operational experience now that these narrowly 
defined provisions have been implemented in place of the broader SSM 
exemptions that were removed from the PCWP NESHAP.
    In their fourth issue raised, the Petitioners disagreed with the 
EPA's statement that use of low-HAP resins is a development under CAA 
section 112(d)(6), claiming that the EPA must revise standards for any 
development identified to require the maximum degree of reduction that 
is achievable through its application. In the 2020 technology review, 
when noting that low-HAP resins were a development, the EPA also 
explained that the EPA did not identify information to suggest that the 
resin system changes have significantly altered the type of process 
units or HAP pollution control technologies used in the PCWP industry 
to date or have led to processes or practices that have not been 
accounted for in the promulgated PCWP NESHAP compliance options. The 
Petitioners dismissed as irrelevant the EPA's explanation that there 
are many types of resin systems used in the manufacture of the various 
PCWP and that the resin-system solution for one facility's product may 
not be applicable for another product produced at a different facility. 
The Petitioners also argued that it is irrelevant that the EPA noted in 
2020 plans for additional action for the PCWP NESHAP source category 
with respect to remanded PCWP process units in which the EPA would 
further consider the effects of resin system changes.
    Given the Petitioners' objections, we are rearticulating our 
conclusion from the August 13, 2020, final technology review. 
Specifically, we are retracting our characterization of low-HAP resins 
as a ``development'' under CAA section 112(d)(6) with respect to the 
standards established for the PCWP source category in 2004. As noted in 
2020, the EPA did not identify information suggesting that the resin 
system changes have significantly altered the type of process units or 
HAP pollution control technologies used in the PCWP industry or have 
led to processes or practices that were not accounted for in the 2004 
promulgated PCWP NESHAP compliance options. Therefore, we agree with 
the Petitioners that it may have been inappropriate to describe resin 
changes as a ``development'' under CAA section 112(d)(6) since the 2004 
promulgated standards. Moreover, we disagree with the Petitioners' 
claim that if resin changes were in fact such a ``development,'' the 
EPA would be required to establish MACT standards under CAA section 
112(d)(2) and (3) as a consequence of that development. CAA section 
112(d)(6) does not require the EPA to reconduct MACT determinations, as 
the D.C. Circuit made clear in NRDC v. EPA, 529 F.3d 1077 (D.C. Cir. 
2008). Instead, CAA section 112(d)(6) provides that the EPA is to 
exercise its judgment to determine what revisions to preexisting 
standards are necessary, after considering such developments. In any 
event, as discussed in section IV.C.1 of this preamble, in this 
action--in order to address previously unregulated HAP emissions, 
respond to the 2007 partial remand and vacatur of the 2004 NESHAP, and 
comport with the LEAN ruling--we are under CAA section 112(h) setting 
standards for RMH process units for which no emission standards are 
currently in place, based on the use of non-HAP resins or resins with 
low vapor pressure (and therefore low potential for HAP emissions) 
including resin types which were available at the time of the 2004 
rule.

[[Page 31882]]

G. What compliance dates are we proposing, and what is the rationale 
for the proposed compliance dates?

    Amendments to the PCWP NESHAP proposed in this rulemaking for 
adoption under CAA section 112(d)(2) and (3) are subject to the 
compliance deadlines outlined in the CAA under CAA section 112(i). For 
existing sources, CAA section 112(i)(3) provides that there shall be 
compliance ``as expeditiously as practicable, but in no event later 
than 3 years after the effective date of such standard'' subject to 
certain exemptions further detailed in the statute.\20\ In determining 
what compliance period is as ``expeditious as practicable,'' we 
consider the amount of time needed to plan and construct projects and 
change operating procedures. As provided in CAA section 112(i), all new 
affected sources would comply with these provisions by the effective 
date of the final amendments to the PCWP NESHAP or upon startup, 
whichever is later.
---------------------------------------------------------------------------

    \20\ Association of Battery Recyclers v. EPA, 716 F.3d 667, 672 
(D.C. Cir. 2013) (``Section 112(i)(3)'s 3-year maximum compliance 
period applies generally to any emission standard . . . promulgated 
under [section 112]'' (brackets in original)).
---------------------------------------------------------------------------

    The EPA projects that many existing sources would need to make 
changes (e.g., review operations, assemble documentation, install add-
on controls and monitoring equipment) to comply with the proposed 
limits for various process units in their facility. These sources would 
require time to develop plans, construct, conduct performance testing, 
and implement monitoring to comply with the revised provisions. 
Therefore, we are proposing to allow 3 years for existing sources to 
become compliant with the new emission standards.
    All affected facilities would have to continue to meet the current 
provisions of 40 CFR part 63, subpart DDDD, until the applicable 
compliance date of the amended rule.
    For all affected sources that commence construction or 
reconstruction on or before May 18, 2023, we are proposing that it is 
necessary to provide 3 years after the effective date of the final rule 
for owners and operators to comply with the provisions of this action. 
For all affected sources that commenced construction or reconstruction 
after May 18, 2023, we are proposing that owners and operators comply 
with the provisions by the effective date of the final rule (or upon 
startup, whichever is later). The effective date is the date of 
publication of the final amendments in the Federal Register.
    As noted previously, the affected source is the collection of 
process units at a PCWP facility. Examples of new affected sources are 
new greenfield PCWP or lumber facilities, existing facilities 
constructing new PCWP manufacturing process lines in addition to (or as 
a replacement for) existing process lines, and existing lumber 
facilities adding (or replacing) lumber kilns in projects that meet the 
definition of reconstruction.
    We solicit comment on these proposed compliance periods, and we 
specifically request submission of information from sources in this 
source category regarding specific actions that would need to be 
undertaken to comply with the proposed amended provisions and the time 
needed to make the adjustments for compliance with any of the revised 
provisions. We note that information provided may result in changes to 
the proposed compliance dates.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    There are currently 223 major-source facilities subject to the PCWP 
NESHAP. We estimate that 6 new PCWP facilities will be constructed and 
become subject to the NESHAP in the next 5 years.

B. What are the air quality impacts?

    This proposed action is expected to reduce HAP and VOC emissions 
from the PCWP source category. In comparison to baseline emissions of 
7,474 tpy HAP and 55,349 tpy VOC,\21\ the EPA estimates HAP and VOC 
emission reductions of approximately 591 tpy and 8,051 tpy, 
respectively. We also estimate that the proposed action would result in 
additional reductions of 231 tpy of PM, 164 tpy of PM2.5, 
132 tpy of NOX, 718 tpy of CO, 12 tpy of SO2, 
129,741 tpy of CO2, 11 tpy of methane (CH4), and 
4.7 tpy of nitrous oxide (N2O). The reduction in 
CO2, CH4, and N2O combined is also 
equal to 130,455 carbon dioxide equivalent (CO2e).
---------------------------------------------------------------------------

    \21\ Baseline emissions are from uncontrolled process units; 
i.e., they do not include emissions from process units regulated by 
the NESHAP.
---------------------------------------------------------------------------

    Secondary air impacts associated with the proposed action are 
estimated to result in emissions increases of 5.4 tpy of PM, 2.0 tpy of 
PM2.5, 22 tpy of CO, 2.7E-04 tpy of Hg, 14 tpy of 
NOX, 14 tpy of SO2, 23,227 tpy CO2, 
1.8 tpy of CH4, and 0.26 tpy of N2O. The increase 
in the CO2, CH4, and N2O is also equal 
to 23,350 CO2e. More information about the estimated 
emission reductions and secondary impacts of this proposed action can 
be found in the document Cost, Environmental, and Energy Impacts of 
Subpart DDDD Regulatory Options in EPA Docket ID No. EPA-HQ-OAR-2016-
0243.

C. What are the cost impacts?

    The EPA estimates that this proposed action would cost 
approximately $126 million in total capital costs (distributed across 
multiple years) and $51 million per year (in 2021 dollars) in total 
annualized costs. More information about the estimated cost of this 
proposed action can be found in the document Cost, Environmental, and 
Energy Impacts of Subpart DDDD Regulatory Options contained in the 
docket for this action.

D. What are the economic impacts?

    For the proposed rule, the EPA estimated the cost of compliance 
with the proposed emission limits. This includes the capital costs of 
installation, and subsequent maintenance and operation of the controls 
as well as other one-time and annual costs. To assess the potential 
economic impacts, the expected annual cost was compared to the total 
sales revenue for the ultimate owners of affected facilities. For this 
rule, the expected annual cost is $228,700 (on average) for each 
facility, with an estimated nationwide annual cost of $51,000,000. The 
223 affected facilities are owned by 65 parent companies, and the total 
costs associated with the proposed amendments are expected to be on 
average about 0.2 percent of annual sales revenue per ultimate owner.
    Information on our cost and economic impact estimates for the PCWP 
manufacturing source category is available in the docket for this 
proposed rule (Docket ID No EPA-HQ-OAR-2016-0243).

E. What are the benefits?

    Implementing the proposed amendments is expected to reduce 
emissions of HAP and non-HAP pollutants, such as VOC. In this section, 
we provide a qualitative discussion of the benefits of this proposed 
rule and HAP health effects.

[[Page 31883]]

    We estimate that the proposed amendments would reduce HAP emissions 
from the source category by approximately 591 tpy. The amendments would 
regulate emissions of acetaldehyde, acrolein, formaldehyde, methanol, 
phenol, propionaldehyde, non-Hg HAP metals, Hg, HCl, PAH, D/F and MDI. 
Information regarding the health effects of these compounds can be 
found in Health Effects Notebook for Hazardous Air Pollutants (at 
https://www.epa.gov/haps/health-effects-notebook-hazardous-air-pollutants) and in the EPA Integrated Risk Information System (IRIS) 
database (at https://iris.epa.gov/AtoZ/?list_type=alpha).
    The proposed amendments would reduce emissions of VOC which, in 
conjunction with NOX and in the presence of sunlight, form 
ground-level ozone (O3). There are health benefits of 
reducing VOC emissions in terms of the number and value of avoided 
ozone-attributable deaths and illnesses. The Integrated Science 
Assessment for Ozone (Ozone ISA) \22\ as summarized in the TSD for the 
Final Revised Cross State Air Pollution Rule Update \23\ synthesizes 
the toxicological, clinical, and epidemiological evidence to determine 
whether each pollutant is causally related to an array of adverse human 
health outcomes associated with either acute (i.e., hours or days-long) 
or chronic (i.e., years-long) exposure. For each outcome, the ISA 
reports this relationship to be causal, likely to be causal, suggestive 
of a causal relationship, inadequate to infer a causal relationship, or 
not likely to be a causal relationship.
---------------------------------------------------------------------------

    \22\ U.S. EPA. 2020. Integrated Science Assessment for Ozone and 
Related Photochemical Oxidants. U.S. Environmental Protection 
Agency. Washington, DC. Office of Research and Development. EPA/600/
R-20/012. Available at: https://www.epa.gov/isa/integrated-science-assessment-isa-ozone-and-related-photochemical-oxidants.
    \23\ U.S. EPA. 2021. Regulatory Impact Analysis Final Revised 
Cross-State Air Pollution Rule Update for the 2008 Ozone NAAQS. 
Available at https://www.epa.gov/sites/default/files/2021-03/documents/revised_csapr_update_ria_final.pdf.
---------------------------------------------------------------------------

    In brief, the Ozone ISA found short-term (less than 1 month) 
exposures to ozone to be causally related to respiratory effects, a 
``likely to be causal'' relationship with metabolic effects and a 
``suggestive of, but not sufficient to infer, a causal relationship'' 
for central nervous system effects, cardiovascular effects, and total 
mortality. The ISA reported that long-term exposures (1 month or 
longer) to ozone are ``likely to be causal'' for respiratory effects 
including respiratory mortality, and a ``suggestive of, but not 
sufficient to infer, a causal relationship'' for cardiovascular 
effects, reproductive effects, central nervous system effects, 
metabolic effects, and total mortality.

F. What analysis of environmental justice did we conduct?

    Following the directives set forth in multiple Executive orders, 
the Agency has evaluated the impacts of this action on communities with 
EJ concerns. Executive Order 12898 directs the EPA to identify the 
populations of concern who are most likely to experience unequal 
burdens from environmental harms--specifically, minority populations 
(i.e., people of color and/or Indigenous peoples) and low-income 
populations (59 FR 7629; February 16, 1994). Additionally, Executive 
Order 13985 is intended to advance racial equity and support 
underserved communities through Federal Government actions (86 FR 7009; 
January 25, 2021).
    The EPA defines EJ as the fair treatment and meaningful involvement 
of all people regardless of race, color, national origin, or income, 
with respect to the development, implementation, and enforcement of 
environmental laws, regulations, and policies.\24\ The EPA further 
defines fair treatment to mean that no group of people should bear a 
disproportionate burden of environmental harms and risks, including 
those resulting from the negative environmental consequences of 
industrial, governmental, and commercial operations or programs and 
policies. In recognizing that people of color and low-income 
populations often bear an unequal burden of environmental harms and 
risks, the EPA continues to consider ways of protecting them from 
adverse public health and environmental effects of air pollution.
---------------------------------------------------------------------------

    \24\ https://www.epa.gov/environmentaljustice.
---------------------------------------------------------------------------

    To examine the potential for any EJ issues that might be associated 
with PCWP manufacturing facilities, we performed a demographic 
analysis, which is an assessment of individual demographic groups of 
the populations living within 5 kilometers (km) and 50 km of the 
facilities. The EPA then compared the data from this analysis to the 
national average for each of the demographic groups.
    The results of the demographic analysis (see table 1 of this 
preamble) indicate that the population percentages for certain 
demographic groups within 5 km of the 223 facilities are greater than 
the corresponding nationwide percentages. The demographic percentage 
for populations residing within 5 km of facility operations is 9 
percentage points greater than its corresponding nationwide percentage 
for the African American population (21 percent within 5 km of the 
facilities compared to 12 percent nationwide), 7 percentage points 
greater than its corresponding nationwide percentage for the population 
living below the poverty level (20 percent within 5 km of the 
facilities compared to 13 percent nationwide), and 2 percentage points 
greater than its corresponding nationwide percentage for the population 
25 years old and older without a high school diploma (14 percent within 
5 km of the facilities compared to 12 percent nationwide). The 
remaining demographic groups within 5 km of facility operations are 
less than, or within one percentage point of, the corresponding 
nationwide percentages. It should be noted that, the average percent of 
the population that is Native American living within 5 km of the 223 
facilities is 1.1 percent, which is over 1.5 times the national 
average. This is largely driven by populations living within 5 km of 16 
facilities where the percent Native American population is over 5 times 
the national average. These facilities are located in Washington (3 
facilities), Oklahoma (4 facilities), Texas, Louisiana, South Dakota, 
Wisconsin, Minnesota, Oregon, Maine, Florida, and South Carolina.
    In addition, the proximity results presented in table 1 of this 
preamble indicate that the population percentages for certain 
demographic groups within 50 km of the 223 facilities are greater than 
the corresponding nationwide percentages. The demographic percentage 
for populations residing within 50 km of the facility operations is 7 
percentage points greater than its corresponding nationwide percentage 
for the African American population (19 percent within 50 km to the 
facilities compared to 12 percent nationwide), and 3 percentage points 
greater than its corresponding nationwide percentage for the population 
living below the poverty level (16 percent within 50 km of the 
facilities compared to 13 percent nationwide). The remaining 
demographic percentages within 50 km of the facilities are less than, 
or within one percentage point of, the corresponding nationwide 
percentages.
    A summary of the proximity demographic assessment performed for the 
major source PCWP manufacturing facilities is included as table 1 of 
this preamble. The methodology and the results of the demographic 
analysis are presented in a technical report, Analysis of Demographic 
Factors for Populations Living Near PCWP Manufacturing Facilities, 
available in this docket for

[[Page 31884]]

this action (Docket ID EPA-HQ-OAR-2016-0243).

        Table 1--Proximity Demographic Assessment Results for Major Source PCWP Manufacturing Facilities
----------------------------------------------------------------------------------------------------------------
                                                                            Population within  Population within
                   Demographic group                         Nationwide        50 km of 223       5 km of 223
                                                                                facilities         facilities
----------------------------------------------------------------------------------------------------------------
Total Population.......................................        328,016,242         34,271,452          1,554,465
                                                        --------------------------------------------------------
                                                                      Race and Ethnicity by Percent
                                                        --------------------------------------------------------
White..................................................                 60                 66                 65
African American.......................................                 12                 19                 21
Native American........................................                0.7                0.7                1.1
Hispanic or Latino (includes white and nonwhite).......                 19                  8                  9
Other and Multiracial..................................                  8                  6                  4
                                                        --------------------------------------------------------
                                                                            Income by Percent
                                                        --------------------------------------------------------
Below Poverty Level....................................                 13                 16                 20
Above Poverty Level....................................                 87                 84                 80
                                                        --------------------------------------------------------
                                                                           Education by Percent
                                                        --------------------------------------------------------
Over 25 and Without a High School Diploma..............                 12                 13                 14
Over 25 and With a High School Diploma.................                 88                 87                 86
                                                        --------------------------------------------------------
                                                                    Linguistically Isolated by Percent
                                                        --------------------------------------------------------
Linguistically Isolated................................                  5                  2                  2
----------------------------------------------------------------------------------------------------------------
Notes:
 The nationwide population count and all demographic percentages are based on the U.S. Census Bureau's
  2015-2019 American Community Survey 5-year block group averages and include Puerto Rico. Demographic
  percentages based on different averages may differ. The total population counts within 5 km and 50 km of all
  facilities are based on the 2010 Decennial Census block populations.
 Minority population is the total population minus the white population.
 To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic
  category for these analyses. A person is identified as 1 of 5 racial/ethnic categories: White, African
  American, Native American, Other and Multiracial, or Hispanic/Latino. A person who identifies as Hispanic or
  Latino is counted as Hispanic/Latino for this analysis, regardless of what race this person may have also
  identified as in the Census.

    The human health risk estimated for this source category for the 
August 13, 2020, RTR (85 FR 49434) was determined to be acceptable, and 
the standards were determined to provide an ample margin of safety to 
protect public health. Specifically, the maximum individual cancer risk 
was 30-in-1 million for actual and allowable emissions and the 
noncancer hazard indices for chronic exposure were below 1 (i.e., 0.8 
for actual and allowable emissions). The maximum noncancer hazard 
quotient for acute exposure was 4. These health risk estimates were 
based on HAP emissions from the source category after addition of air 
pollution controls used to meet the MACT standards promulgated in 2004, 
as well as the baseline HAP emissions from process units for which 
standards are being proposed in this action. While the August 13, 2020, 
amendments to 40 CFR part 63, subpart DDDD, reduced emissions by an 
unquantified amount by removing the startup, shutdown, and malfunction 
exemption and adding repeat testing requirements, the proposed changes 
to 40 CFR part 63, subpart DDDD, in this action would reduce emissions 
by an additional 591 tons of HAP per year and therefore would further 
improve human health exposures for populations in all demographic 
groups. The proposed changes would have beneficial effects on air 
quality and public health for populations exposed to emissions from 
PCWP manufacturing facilities.

VI. Request for Comments

    We solicit comments on this proposed action. In addition to general 
comments on this proposed action, we are also interested in additional 
data that may improve the analyses. If additional HAP performance test 
results are submitted, such data should include supporting 
documentation in sufficient detail to allow characterization of the 
quality and representativeness of the data or information.
    For lumber kilns, we request comment on our proposed conclusions 
with respect to feasibility of capturing and measuring emissions from 
lumber kilns and our conclusions with respect to applicability of add-
on controls for lumber kilns. We request comments on the proposed 
standards, including the proposed O&M plan with its requirement for 
annual inspections in 40 CFR 63.2241(e)(1), proposed requirement for 
annual lumber kiln burner tune-ups in 40 CFR 63.2241(e)(2), and the 
proposed minimum kiln-dried lumber moisture content limits below which 
lumber is considered over-dried lumber for purposes of the PCWP NESHAP 
in 40 CFR 63.2241(e)(4). With respect to the work practice proposed in 
40 CFR 63.2241(e)(3), we request comment on the utility and provisions 
for each of the 3 options (temperature set point, in-kiln lumber 
moisture monitoring, or site-specific plan).
    For RMH units, we request comments on the work practices proposed 
for RMH process units, including comments pertaining to the procedures 
for demonstrating compliance with the requirement to use non-HAP resin 
or resin meeting the proposed maximum true vapor pressure limit and the 
requirement to process dried wood. We also request comment on other 
potential approaches for establishing standards for RMH process units 
considering that the RMH process units are not designed

[[Page 31885]]

and constructed in a way that allows for HAP emissions capture or 
measurement.

VII. Submitting Data Corrections

    The site-specific emissions data used in setting MACT standards for 
PM (non-Hg HAP metals), Hg, acid gases, and PAH, as emitted from the 
PCWP source category, are provided in the docket (Docket ID No. EPA-HQ-
OAR-2016-0243). If you believe that the data are not representative or 
are inaccurate, please identify the data in question, provide your 
reason for concern, and provide any ``improved'' data that you have, if 
available. When you submit data, we request that you provide 
documentation of the basis for the revised values to support your 
suggested changes. For information on how to submit comments, including 
the submittal of data corrections, refer to the instructions provided 
in the introduction of this preamble.

VIII. Statutory and Executive Order Reviews

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

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

    This action is not a significant regulatory action and was 
therefore not submitted to the Office of Management and Budget (OMB) 
for review.

B. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have 
been submitted for approval to OMB under the PRA. The ICR document that 
the EPA prepared has been assigned EPA ICR number 1984.11. You can find 
a copy of the ICR in the docket for this rule, and it is briefly 
summarized here.
    We are proposing changes to the reporting and recordkeeping 
requirements for the PCWP NESHAP by incorporating the reporting and 
recordkeeping requirements associated with the MACT standards being 
added to the rule for multiple HAP from new and existing process units.
    Respondents/affected entities: Owners or operators of PCWP or kiln-
dried lumber manufacturing plants that are major sources, or that are 
located at, or are part of, major sources of HAP emissions.
    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subpart DDDD).
    Estimated number of respondents: On average over the next 3 years, 
approximately 223 existing major sources would be subject to these 
standards. It is also estimated that 6 additional respondents would 
become subject to the emission standards over the 3-year period.
    Frequency of response: The frequency of responses varies depending 
on the burden item (e.g., one-time, semiannual, annual, every 5 years).
    Total estimated burden: The average annual burden to industry over 
the next 3 years from the proposed recordkeeping and reporting 
requirements is estimated to be 46,900 hours per year. Burden is 
defined at 5 CFR 1320.3(b).
    Total estimated cost: The total annual recordkeeping and reporting 
cost for all facilities to comply with all of the requirements in the 
NESHAP, including the requirements in this proposed rule, is estimated 
to be $9,720,000 per year including $4,020,000 in annualized capital 
and O&M costs.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    Submit your comments on the Agency's need for this information, the 
accuracy of the provided burden estimates, and any suggested methods 
for minimizing respondent burden to the EPA using the docket identified 
at the beginning of this rule. The EPA will respond to any ICR-related 
comments in the final rule. You may also send your ICR-related comments 
to OMB's Office of Information and Regulatory Affairs using the 
interface at https://www.reginfo.gov/public/do/PRAMain. Find this 
particular information collection by selecting ``Currently under 
Review--Open for Public Comments'' or by using the search function. OMB 
must receive comments no later than July 17, 2023.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. The 
small entities subject to the requirements of this action are small 
businesses, including one small business owned by a tribal government, 
as defined by the U.S. Small Business Administration (SBA). The EPA 
prepared a small business screening analysis to determine if any of the 
identified affected entities are small entities, as defined by the SBA. 
This analysis is available in the Docket for this action (Docket ID No. 
EPA-HQ-OAR-2016-0243). The Agency has determined that 21 small ultimate 
PCWP manufacturing parent companies out of 65 may experience an impact 
from less than 0.01 percent to 1.94 percent of annual sales, with only 
2 out of these 21 ultimate parent companies experiencing an impact of 
more than 1 percent of annual sales. Because the total annualized costs 
associated with the proposed amendments are expected to be more than 1 
percent of annual sales revenue for only 2 small business ultimate 
parent owners in the PCWP manufacturing source category, there are, 
therefore, no significant economic impacts from these proposed 
amendments on the 27 affected facilities that are owned by 21 affected 
small ultimate parent entities.
    Details of this analysis are presented in Economic Impact and Small 
Business Screening Assessments for Proposed Amendments to the National 
Emission Standards for Hazardous Air Pollutants for Plywood and 
Composite Wood Products Manufacturing Facilities, located in the docket 
for this action (Docket ID No. EPA-HQ-OAR-2016-0243).

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more as described in UMRA, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments. While this action 
creates an enforceable duty on the private sector and one facility 
owned by a tribal government, the cost does not exceed $100 million or 
more.

E. Executive Order 13132: Federalism

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

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

    This action does not have tribal implications as specified in 
Executive Order 13175. Thus, Executive Order 13175 does not apply to 
this action. However, consistent with the EPA policy on coordination 
and consultation with Indian tribes, the EPA will offer government-to-
government consultation with tribes as requested.

[[Page 31886]]

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

    This action is not subject to Executive Order 13045 because the EPA 
does not believe the environmental health or safety risks addressed by 
this action present a disproportionate risk to children. This action 
proposes emission standards for previously unregulated pollutants; 
therefore, the rule should result in health benefits to children by 
reducing the level of HAP emissions from the PCWP manufacturing 
process.

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

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution, or use of energy. In this proposed action, the EPA is 
setting emission standards for previously unregulated pollutants. This 
does not impact energy supply, distribution, or use.

I. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR 
Part 51

    This action involves technical standards. Therefore, the EPA 
conducted searches for the PCWP NESHAP through the Enhanced National 
Standards Systems Network (NSSN) Database managed by the American 
National Standards Institute (ANSI). We also conducted a review of 
voluntary consensus standards (VCS) organizations and accessed and 
searched their databases. We conducted searches for EPA Methods 1, 1A, 
2, 2A, 2C, 2D, 2F, 2G, 3, 3A, 3B, 4, 5, 10, 18, 25A, 26A, 29 of 40 CFR 
part 60, appendix A; 204, 204A, 204B, 204C, 204D, 204E, 204F, 205 of 40 
CFR part 51, appendix M; 308, 316, 320, 326 of 40 CFR part 63; OTM-46, 
and 0011 (SW-846). During the EPA's VCS search, if the title or 
abstract (if provided) of the VCS described technical sampling and 
analytical procedures that are similar to the EPA's referenced method, 
the EPA ordered a copy of the standard and reviewed it as a potential 
equivalent method. We reviewed all potential standards to determine the 
practicality of the VCS for this rule. This review requires significant 
method validation data that meet the requirements of EPA Method 301 for 
accepting alternative methods or scientific, engineering, and policy 
equivalence to procedures in the EPA referenced methods. The EPA may 
reconsider determinations of impracticality when additional information 
is available for any particular VCS.
    Detailed information on the VCS search and determination can be 
found in the memorandum, Voluntary Consensus Standard Results for 
NEHSAP: Plywood and Composite Wood Products, which is available in the 
docket for this action (Docket ID No. EPA-HQ-OAR-2016-0243). Two VCS 
were identified as acceptable alternatives to the EPA test methods for 
this proposed rule.
    The VCS ANSI/ASME PTC 19.10-1981 Part 10 (2010), ``Flue and Exhaust 
Gas Analyses,'' is an acceptable alternative to EPA Method 3B manual 
portions only and not the instrumental portion. This method determines 
quantitatively the gaseous constituents of exhausts resulting from 
stationary combustion sources. The manual procedures (but not 
instrumental procedures) of ASME/ANSI PTC 19.10-1981 Part 10 may be 
used as an alternative to EPA Method 3B for measuring the oxygen or 
carbon dioxide content of the exhaust gas. The gases covered in ASME/
ANSI PTC 19.10-1981 are oxygen, carbon dioxide, carbon monoxide, 
nitrogen, sulfur dioxide, sulfur trioxide, nitric oxide, nitrogen 
dioxide, hydrogen sulfide, and hydrocarbons. However, the use in this 
rule is only applicable to oxygen and carbon dioxide. This VCS may be 
obtained from American Society of Mechanical Engineers (ASME), Three 
Park Avenue, New York, NY 10016-5990, telephone (800) 843-2763, https://www.asme.org. The EPA is proposing to incorporate by reference the VCS 
ANSI/ASME PTC 19.10-1981 Part 10 (2010), ``Flue and Exhaust Gas 
Analyses,'' as an acceptable alternative to EPA Method 3B manual 
portions only and not the instrumental portion.
    The VCS ASTM D6348-12e1, ``Determination of Gaseous Compounds by 
Extractive Direct Interface Fourier Transform (FTIR) Spectroscopy,'' is 
an acceptable alternative to EPA Method 320 with certain conditions. 
The VCS ASTM D6348-12e1 employs an extractive sampling system to direct 
stationary source effluent to an FTIR spectrometer for the 
identification and quantification of gaseous compounds. Concentration 
results are provided. This test method is potentially applicable for 
the determination of compounds that (1) have sufficient vapor pressure 
to be transported to the FTIR spectrometer and (2) absorb a sufficient 
amount of infrared radiation to be detected. The VCS ASTM D6348-12e1 
may be obtained from https://www.astm.org or from the ASTM Headquarters 
at 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, 
Pennsylvania, 19428-2959. The EPA is proposing to incorporate by 
reference the VCS ASTM D6348-12e1, ``Determination of Gaseous Compounds 
by Extractive Direct Interface Fourier Transform (FTIR) Spectroscopy,'' 
as an acceptable alternative to EPA Method 320 in place of ASTM D6348-
03. ASTM D6348-03(2010) was determined to be equivalent to EPA Method 
320 with caveats. ASTM D6348-12e1 is a revised version of ASTM D6348-
03(2010) and includes a new section on accepting the results from the 
direct measurement of a certified spike gas cylinder but lacks the 
caveats placed on the ASTM D6348-03(2010) version. ASTM D6348-12e1 is 
an extractive FTIR field test method used to quantify gas phase 
concentrations of multiple analytes from stationary source effluent and 
is an acceptable alternative to EPA Method 320 at this time with 
caveats requiring inclusion of selected annexes to the standard as 
mandatory. When using ASTM D6348-12e1, the following conditions must be 
met:
     The test plan preparation and implementation in the 
Annexes to ASTM D6348-03, sections A1 through A8 are mandatory; and
     In ASTM D6348-03, Annex A5 (Analyte Spiking Technique), 
the percent (%) R must be determined for each target analyte (Equation 
A5.5).
    In order for the test data to be acceptable for a compound, percent 
R must be 70 percent >= R <= 130 percent. If the percent R value does 
not meet this criterion for a target compound, the test data is not 
acceptable for that compound and the test must be repeated for that 
analyte (i.e., the sampling and/or analytical procedure should be 
adjusted before a retest). The percent R value for each compound must 
be reported in the test report, and all field measurements must be 
corrected with the calculated percent R value for that compound by 
using the following equation:

Reported Results = ((Measured Concentration in Stack))/(percent R) x 
100.

    In addition to the VCS mentioned earlier in this preamble, we are 
proposing to incorporate by reference ASTM D1835-05, ``Standard 
Specification for Liquefied Petroleum (LP) Gases,'' for use in the 
proposed definition of natural gas in 40 CFR 63.2292, and ASTM D2879-
18, ``Standard Test Method for Vapor Pressure-Temperature Relationship 
and Initial Decomposition Temperature of Liquids by Isoteniscope'' for 
use in the

[[Page 31887]]

proposed definition of maximum true vapor pressure in 40 CFR 63.2292. 
The VCS ASTM D-1835-05 covers those products commonly referred to as 
liquefied petroleum gases, consisting of propane, propene (propylene), 
butane, and mixtures of these materials. With ASTM D2879-18, the vapor 
pressure of a substance as determined by isoteniscope reflects a 
property of the sample as received including most volatile components 
but excluding dissolved fixed gases such as air. The isoteniscope 
method is designed to minimize composition changes which may occur 
during the course of measurement. These VCS ASTM may be obtained from 
https://www.astm.org or from the ASTM Headquarters at 100 Barr Harbor 
Drive, P.O. Box C700, West Conshohocken, Pennsylvania, 19428-2959.

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

    Executive Order 12898 (59 FR 7629, February 16, 1994) directs 
Federal agencies, to the greatest extent practicable and permitted by 
law, to make environmental justice part of their mission by identifying 
and addressing, as appropriate, disproportionately high and adverse 
human health or environmental effects of their programs, policies, and 
activities on minority populations (people of color and/or Indigenous 
peoples) and low-income populations.
    The EPA believes that the human health or environmental conditions 
that exist prior to this action result in or have the potential to 
result in disproportionate and adverse human health or environmental 
effects on people of color, low-income populations, and/or Indigenous 
peoples. The assessment of populations in close proximity of PCWP 
manufacturing facilities shows that the percentage of African 
Americans, Native Americans, people below poverty level, and people 
over 25 without a high school diploma are higher than the national 
average (see section V.F of the preamble). The higher percentages are 
driven by 19 of the 223 facilities in the source category.
    The EPA believes that this action is likely to reduce existing 
disproportionate and adverse effects on people of color, low-income 
populations, and/or Indigenous peoples. The EPA is proposing MACT 
standards for total HAP, MDI, PM as a surrogate for non-Hg metals, Hg, 
HCl, PAH, and D/F. The EPA expects all 223 PCWP facilities to implement 
changes to comply with the MACT standards (e.g., control measures, work 
practices, emissions testing, monitoring, reporting, and recordkeeping 
for the process units used) and expects that HAP exposures for the 
people of color and low-income individuals living near these facilities 
would decrease.
    The information supporting this Executive Order review is contained 
in section V.F of this preamble.

List of Subjects in 40 CFR Part 63

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

Michael S. Regan,
Administrator.
[FR Doc. 2023-10067 Filed 5-17-23; 8:45 am]
BILLING CODE 6560-50-P


