

[Federal Register: February 16, 2006 (Volume 71, Number 32)]
[Rules and Regulations]               
[Page 8341-8387]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr16fe06-10]                         


[[Page 8341]]

-----------------------------------------------------------------------

Part II





Environmental Protection Agency





-----------------------------------------------------------------------



40 CFR Part 63



National Emission Standards for Hazardous Air Pollutants: Plywood and 
Composite Wood Products; List of Hazardous Air Pollutants, Lesser 
Quantity Designations, Source Category List; Final Rule


[[Page 8342]]


-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[OAR-2003-0048; FRL-8028-9]
RIN 2060-AN05

 
National Emission Standards for Hazardous Air Pollutants: Plywood 
and Composite Wood Products; List of Hazardous Air Pollutants, Lesser 
Quantity Designations, Source Category List

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule, amendments; notice of final action on 
reconsideration.

-----------------------------------------------------------------------

SUMMARY: On July 30, 2004, EPA promulgated national emission standards 
for hazardous air pollutants (NESHAP) for the plywood and composite 
wood products (PCWP) source category. The Administrator subsequently 
received a petition for reconsideration of certain provisions in the 
final rule. In addition, following promulgation, stakeholders expressed 
concern with some of the final rule requirements including definitions, 
the emissions testing procedures required for facilities demonstrating 
eligibility for the low-risk subcategory, stack height calculations to 
be used in low-risk subcategory eligibility demonstrations, and 
permitting and timing issues associated with the low-risk subcategory 
eligibility demonstrations. In two separate Federal Register notices 
published on July 29, 2005, we announced our reconsideration of certain 
aspects of the final rule, and we proposed amendments to the final 
rule. In the notice of reconsideration, we requested public comment on 
the approach used to establish and delist a low-risk subcategory of 
PCWP affected sources, as outlined in the final rule, and on an issue 
related to the final rule's startup, shutdown, and malfunction (SSM) 
provisions. In the proposed amendments notice, we proposed simplifying 
the requirements for the low-risk demonstrations (LRD) and allowing 
additional time for facilities to submit them. We also requested 
comment on whether to extend the MACT compliance date. We also 
clarified some common applicability questions. In this action, we are 
promulgating amendments to the PCWP NESHAP and providing our 
conclusions following the reconsideration process.

DATES: February 16, 2006. The incorporation by reference of one 
publication listed in this final action is approved by the Director of 
the Office of the Federal Register as of February 16, 2006.

ADDRESSES: Docket. The EPA has established a docket for this action 
under Docket ID No. OAR-2003-0048 and Legacy Docket ID No. A-98-44. All 
documents in the docket are listed on the http://www.regulations.gov Web site. 

Although listed in the index, 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 form. Publicly 
available docket materials are available either electronically through 
http://www.regulations.gov or in hard copy at the Air and Radiation Docket and 

Information Center, EPA/DC, EPA West, Room B102, 1301 Constitution 
Ave., NW, Washington, DC. The Public Reading Room is open from 8:30 
a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The 
telephone number for the Public Reading Room is (202) 566-1744, and the 
telephone number for the Air and Radiation Docket and Information 
Center is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: For information concerning 
applicability and rule determinations, contact your State or local 
representative or appropriate EPA Regional Office representative. For 
information concerning rule development, contact Ms. Mary Tom Kissell, 
Sector Policies and Program Division, (Mailcode: C439-03), EPA, 
Research Triangle Park, NC 27711; telephone number: (919) 541-4516; fax 
number: (919) 541-0246; e-mail address: kissell.mary@epa.gov.

SUPPLEMENTARY INFORMATION:

Regulated Entities

    Categories and entities potentially affected by today's action 
include:

------------------------------------------------------------------------
                               SIC code    NAICS         Examples of
          Category                a        code b    regulated entities
------------------------------------------------------------------------
Industry....................       2421     321999  Sawmills with lumber
                                                     kilns.
                                   2435     321211  Hardwood plywood and
                                                     veneer plants.
                                   2436     321212  Softwood plywood and
                                                     veneer plants.
                                   2493     321219  Reconstituted wood
                                                     products plants
                                                     (particleboard,
                                                     medium density
                                                     fiberboard,
                                                     hardboard,
                                                     fiberboard, and
                                                     oriented
                                                     strandboard
                                                     plants).
                                   2439     321213  Structural wood
                                                     members, not
                                                     elsewhere
                                                     classified
                                                     (engineered wood
                                                     products plants).
------------------------------------------------------------------------
 a Standard Industrial Classification.
 b North American Industrial Classification System.

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be affected by today's 
action. To determine whether your facility is affected by today's 
action, you should examine the applicability criteria in Sec.  63.2231 
of the final rule. If you have questions regarding the applicability of 
today's action to a particular entity, consult Ms. Mary Tom Kissell 
listed in the preceding FOR FURTHER INFORMATION CONTACT section.

Worldwide Web (WWW)

    In addition to being available in the docket, an electronic copy of 
today's action also will be available on the Worldwide Web (WWW) 
through EPA's Technology Transfer Network (TTN). Following the 
Administrator's signature, a copy of this action will be posted on the 
TTN's policy and guidance page for newly promulgated rules at http://www.epa.gov/ttn/oarpg.
 The TTN provides information and technology 

exchange in various areas of air pollution control.

Judicial Review

    Under section 307(b)(1) of the CAA, judicial review of the final 
rule amendments to the NESHAP is available by filing a petition for 
review in the U.S. Court of Appeals for the District of Columbia 
Circuit by April 17, 2006. Under section 307(d)(7)(B) of the CAA, only 
those objections that were raised with reasonable specificity during 
the period for public comment may be raised during judicial review. 
Under section 307(b)(2) of the CAA, the requirements that are the 
subject of the

[[Page 8343]]

final rule amendments may not be challenged later in civil or criminal 
proceedings brought by EPA to enforce the requirements.

Outline

    The information presented in this preamble is organized as follows:

I. Background
II. Comments and Responses on Low-risk Option
    A. Legal Basis
    B. Background Pollution and Co-located Emission Sources
    C. Ecological Risk
    D. The Dose-Response Value Used for Formaldehyde
    E. Appendix B to 40 CFR Part 63 Subpart DDDD Requirements
    F. Selection of Process Units and Emissions Determination 
Procedures in Table 2A to Appendix B to 40 CFR Part 63 Subpart DDDD
    G. Emission Testing Requirements in Appendix B to 40 CFR Part 63 
Subpart DDDD
    H. Compliance Date for Existing Sources
    I. Low-Risk Demonstration Submittal Dates for Existing Sources
    J. Compliance Date for Affected Sources Previously Qualifying 
For the Low-Risk Subcategory
    K. Low-Risk Demonstration Submittal Dates for New Sources
    L. Legal Issues With Title V Implementation Mechanism
    M. Timing of Title V Permit Revisions
    N. Permit Conditions
    O. Costs and Benefits of Establishing a Low-Risk Subcategory
III. Responses to Comments on the Proposed Amendments and 
Clarifications for Subpart DDDD
    A. Definitions
    B. Applicability of the PCWP Rule to Lumber Kilns Drying Utility 
Poles
    C. Capture Efficiency Determination
    D. Incorporation by Reference of NCASI Method ISS/FP-A105.01
IV. Responses to Comments on SSM Issues
V. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Congressional Review Act

I. Background

    We proposed NESHAP for the PCWP source category on January 9, 2003 
(68 FR 1276). The preamble for the proposed rule requested comment on 
how and whether we should incorporate risk-based approaches into the 
final rule to avoid imposition of regulatory controls on facilities 
that pose little risk to public health and the environment. Fifty-seven 
interested parties submitted comments on the proposed rule during the 
comment period. The final rule (subpart DDDD in 40 CFR part 63) was 
published on July 30, 2004 (69 FR 45944) after consideration of these 
comments. We adopted a risk-based approach in the final rule by 
establishing and delisting a low-risk subcategory of PCWP affected 
sources based on our authority under section 112(c)(1) and (9) of the 
Clean Air Act (CAA). Under this approach, PCWP affected sources may 
submit for EPA approval proposed demonstrations that they meet certain 
risk-based criteria and, therefore, are eligible to join the low-risk 
subcategory and avoid applicability of the PCWP NESHAP. The methodology 
and criteria for PCWP affected sources to use in demonstrating that 
they are part of the delisted low-risk subcategory were promulgated in 
appendix B to subpart DDDD of 40 CFR part 63. Sources whose LRD EPA 
approves then must seek permit revisions under title V of the CAA that 
incorporate their low-risk parameters as enforceable terms and 
conditions in order to ensure they remain low-risk and remain exempt 
from otherwise applicable PCWP NESHAP requirements.
    Following promulgation of the final PCWP rule, the Administrator 
received a petition for reconsideration filed by the Natural Resources 
Defense Council (NRDC) and Environmental Integrity Project (EIP) 
pursuant to section 307(d)(7)(B) of the CAA.\1\ The petition requested 
reconsideration of nine aspects of the final rule: (1) Risk assessment 
methodology, (2) background pollution and co-located emission sources, 
(3) dose-response value used for formaldehyde, (4) costs and benefits 
of the low-risk subcategory, (5) ecological risk, (6) legal basis for 
the risk-based approach, (7) maximum achievable control technology 
(MACT) compliance date for affected sources previously qualifying for 
the low-risk subcategory, (8) SSM provisions, and (9) title V 
implementation mechanism for the risk-based approach. The petitioners 
stated that reconsideration of the above issues is appropriate because 
they claimed that the issues could not have been practicably raised 
during the public comment period. The petition for reconsideration also 
requested a stay of the effectiveness of the risk-based provisions.
---------------------------------------------------------------------------

    \1\ In addition to the petition for reconsideration, four 
petitions for judicial review of the final PCWP rule were filed with 
the U.S. Court of Appeals for the District of Columbia by NRDC and 
Sierra Club (No. 04-1323, D.C. Cir.), EIP (No. 04-1235, D.C. Cir.), 
Louisiana-Pacific Corporation (No. 04-1328, D.C. Cir.), and Norbord 
Incorporated (No. 04-1329, D.C. Cir.). The four cases have been 
consolidated. In addition, the following parties have filed as 
interveners: American Forest and Paper Association (AF&PA), Hood 
Industries, Scotch Plywood, Coastal Lumber Company, Composite Panel 
Association, APA-The Engineered Wood Association, American Furniture 
Manufacturers Association, NRDC, Sierra Club, and EIP. Finally, the 
Formaldehyde Council, Inc. and the State and Territorial Air 
Pollution Program Administrators and Association of Local Air 
Pollution Control Officials (STAPPA/ALAPCO) are participating in the 
litigation as amicus curiae.
---------------------------------------------------------------------------

    In a letter dated December 6, 2004, EPA granted NRDC's and EIP's 
petition for reconsideration and declined the petitioners' request that 
we take action to stay the effectiveness of the risk-based provisions. 
On July 29, 2005 (70 FR 44012), we published a notice of 
reconsideration to initiate rulemaking by requesting comments on the 
issues in the petition for reconsideration, including the full content 
of appendix B to subpart DDDD.
    In a separate notice published on July 29, 2005 (70 FR 44012), we 
proposed amendments to subpart DDDD and both of the appendices to 
subpart DDDD. We proposed amendments to appendix B to subpart DDDD to 
reduce the number of emissions tests required while ensuring that 
emissions from all PCWP process units at the relevant source are 
considered when demonstrating eligibility for the low-risk subcategory. 
For emission points that would still require emission tests, we 
proposed that the emissions tests may be conducted after the LRD is 
submitted. We also proposed that physical changes necessary to achieve 
low-risk status may be completed after the LRD is submitted. We 
proposed to alter the way the stack height is calculated for a look-up 
table analysis and to clarify some timing issues related to LRD, 
including the deadline for submitting LRD. We also requested comment on 
whether the MACT compliance date should be extended for sources 
submitting LRD or for all sources. Furthermore, we proposed to amend 
subpart A to 40 CFR part 63, subpart DDDD of 40 CFR part 63, and 
appendix B to subpart DDDD to allow use of a new test method developed 
by the National Council of the Paper Industry for Air and Stream 
Improvement (NCASI) for measuring hazardous air pollutants (HAP).
    For 40 CFR part 63, subpart DDDD, we proposed several changes to 
ensure that the rule is implemented as intended: (1) Amend the sampling 
location for coupled control devices, (2) amend language to clarify 
rule

[[Page 8344]]

applicability during unscheduled startups and shutdowns, (3) add 
language to clarify rule applicability for affected sources with no 
process units subject to compliance options or work practice 
requirements, and (4) amend selected definitions. A minor numbering 
error was proposed to be corrected in appendix A to 40 CFR part 63, 
subpart DDDD. We also clarified some common applicability questions, 
and we requested comments on whether to extend the deadline for 
compliance with the rule's requirements for all subject sources.
    We received public comments from nine stakeholders on the 
reconsideration issues during the comment period. Although some 
commenters on the 2005 reconsideration referred to previous comments 
they submitted following the 2003 proposal, we have not included the 
previous comments in the summary presented here unless they are 
directly relevant to the reconsideration. However, the previous 
comments are included in the docket for this final rulemaking or the 
background information document (BID). Our responses to comments today 
are intended to respond to the comments specifically submitted on our 
proposed reconsideration notice and to any relevant incorporated 
comments. We received public comments from 12 stakeholders on the 
proposed amendments during the comment period. We received supporting 
comments only (or no comments) on a number of the proposed amendments, 
including the proposed amendment to the: (1) Sampling location for 
coupled control devices; (2) definitions of ``molded particleboard,'' 
``plywood and composite wood products manufacturing facility,'' and 
``plywood''; (3) requirements for affected sources with no process 
units subject to the compliance options or work practice requirements; 
(4) numbering of paragraphs referenced in 40 CFR 63.2269; (5) test 
methods for benzene; (6) criteria for assuming zero for Method 29 non-
detect measurements; and (7) numbering of appendix A to 40 CFR part 63, 
subpart DDDD. We have promulgated these amendments as proposed based on 
the rationale provided in the proposed rule (70 FR 44012, July 29, 
2005), and no further discussion of these amendments is presented here. 
We are also promulgating a revised compliance deadline for sources 
subject to the rule, which is one year later than the date originally 
promulgated. The new compliance deadline is October 1, 2008. Our 
rationale for this revision is contained in our responses below.

II. Comments and Responses on Low-risk Option

A. Legal Basis

    Comment: Several commenters stated that there are numerous ways in 
which the risk-based exemptions contravene the language, structure, and 
history of the 1990 CAA amendments and EPA's past policies. The 
commenters noted that technology-based standards should precede risk-
based standards, that creating a subcategory based on risk is illegal, 
that delaying the compliance date to allow the risk-based standards is 
contrary to the CAA, that not setting emission standards is generally 
not authorized, that considering sources in the low-risk subcategory 
when establishing MACT floors is not allowed by the CAA, and that the 
CAA does not authorize EPA to delist subcategories (versus categories) 
of sources of carcinogenic emissions.
    Other commenters stated there is ample legal basis for establishing 
and delisting the low-risk PCWP subcategory and supported retaining the 
low-risk option.
    Response: After considering the 2003 proposed PCWP NESHAP and the 
public comments submitted thereon, the 2004 final PCWP NESHAP, the 
petition for reconsideration of the final PCWP NESHAP, the 2005 notice 
of final PCWP NESHAP reconsideration and the comments submitted in 
response to that notice, EPA stands by the legal rationale for the PCWP 
low-risk approach explained in the 2004 final PCWP NESHAP (69 FR 45983-
45991, July 30, 2004) and incorporates that rationale by reference.
    Regarding the comments on the proposed reconsideration that raised 
new points or elaborated on points previously made, the explanation for 
why risk may be an appropriate criterion for distinguishing between 
sources in establishing source categories and subcategories has been 
clearly set forth in the general policy rationale for the final PCWP 
NESHAP and today's final action on reconsideration. CAA section 
112(c)(9) shows that Congress intended that EPA be able, either in 
advance of or following the promulgation of emission standards under 
section 112, to remove source categories and subcategories from 
regulation under section 112 ``whenever'' relevant risk-based findings 
are made.
    We disagree that the risk-based approach causes a delay in the 
compliance date for MACT in contravention of section 112(d)(1) and 
112(i). This is because the PCWP sources that remain in the MACT 
category must meet emission standards by the promulgated MACT deadline, 
and any sources that wish to join the low-risk subcategory and avoid 
MACT at the compliance deadline must, on that date, either comply with 
MACT or have been approved as a member of the low-risk subcategory. 
While we have in today's final rule revised the MACT compliance 
deadline to fall one year later than was originally promulgated, this 
revision is not a result of the mere inclusion of the action we have 
taken under section 112(c)(9). Rather, it is a result of the 
significance of the changes we have made to the PCWP NESHAP overall, as 
well as changed expectations about the scope of MACT-subject and would-
be low-risk sources who will need to obtain, install, and certify 
emissions controls. It is also true that a source that is low-risk and 
exempt from MACT at the compliance date may later undergo changes that 
subject it to MACT for the first time, and that the PCWP rule in some 
cases allows such a source to comply with MACT 3 years after it has 
lost its low-risk status. This is consistent, however, with how we 
treat area sources that change status to major sources and thereby join 
a MACT-regulated category for the first time.
    We also disagree that once EPA lists a category or subcategory, it 
is absolutely required by section 112(c)(2) and 112(d)(1) to set 
emission standards for that category or subcategory. Section 112(c)(9) 
itself depends upon the identification of a ``category'' or 
``subcategory'' as identifying the set of major sources that may be 
deleted from the list of sources to be regulated, and indeed by its 
terms assumes that the category or subcategory may be ``on the list'' 
(and possibly already regulated) before EPA determines that the risk-
based criteria to justify its removal have been met.
    As we previously explained in the 2004 final PCWP NESHAP, the 
approach we have taken for the low-risk PCWP subcategory is not the 
source-by-source granting of risk-based exemptions rejected by Congress 
in the 1990 CAA amendments. That approach would have allowed any 
source, in any source category, to seek an exemption from section 112 
standards, without demonstrating that it qualified under previously 
established criteria to join an already existent delisted subcategory, 
and without subsequent compliance responsibilities such as having to 
incorporate its parameters reflecting low-risk eligibility into 
federally enforceable permit terms and

[[Page 8345]]

conditions. The PCWP approach, instead, operates more like the 
applicability determination process that a source uses to discover 
which set of multiple sets of applicable requirements under the CAA it 
must comply with. If a PCWP source is not low-risk, it must meet MACT; 
but if it meets the low-risk criteria, it must still meet specific, 
enforceable requirements that can be enforced through the title V 
permit to the same extent as otherwise applicable MACT standards. Our 
approach is not the same as the rejected ``de minimis'' exemption since 
sources must specifically show that they meet the statutory criteria of 
section 112(c)(9) that define the low-risk PCWP source category, 
criteria that are explicitly enumerated in the statutory language 
itself, rather than based on a legal doctrine allowing exemptions from 
statutory requirements notwithstanding the absence of express statutory 
language for such exemption.
    We are surprised by the commenter's assertion that our MACT floors 
for non-low-risk PCWP sources may not be based, in part, on emissions 
limitation achieved by sources that subsequently show they are eligible 
for inclusion in the low-risk PCWP subcategory. When we develop MACT 
standards, we necessarily start at a step where we do not already know 
what the scope of the final standards' requirements will ultimately be. 
In identifying the MACT floors for new and existing sources under 
section 112(d)(2) and 112(d)(3), it is simply not possible to know with 
certainty exactly which sources will have to meet MACT requirements. In 
fact, it is always possible that any major source will change its 
emissions or operations prior to the compliance date such that it is no 
longer major and, therefore, not subject to the final standards. In the 
case of PCWP, our approach presumes that nearly all sources are in the 
MACT category at the outset and that sources may join the non-MACT 
subcategory over time, but it would be impossible at the MACT floor 
determination stage to estimate the ultimate population of low-risk 
sources, just as it is impossible to estimate the number of major 
sources that may become ``area'' sources before the MACT compliance 
dates. In both cases, it would not be administratively feasible--nor is 
it legally required--to adjust the MACT floor determination over time 
as the MACT category population changes. There is no indication in the 
CAA that such an approach, especially to the extent it excluded better-
performing sources from floor determinations and thereby weakened 
technology-based standards, would be consistent with Congress's overall 
purpose in basing section 112(d) standards on the emissions levels 
achieved in practice by the best-performing sources.
    Regarding the issue of whether EPA may delist only ``categories'' 
of sources that emit carcinogens, but not ``subcategories,'' EPA agrees 
with the commenters that suggest there is functionally no difference 
between the two terms, and that it is unnecessary to resolve the debate 
over whether Congress committed a ``scrivener's error'' raised by other 
commenters. In section 112(c), Congress provides EPA with broad 
discretion in not only defining the criteria to be used to identify 
individual categories and subcategories, but in deciding when one group 
of sources might constitute a ``category'' versus a ``subcategory,'' 
there is literally no statutory definition of either term, and the use 
of one over the other to define a group of sources is merely a semantic 
distinction with no legal difference.
    Regarding the commenter's objections to EPA's discussion regarding 
congressional intent related to our authority to establish and delist 
source categories and subcategories, we conclude that it is not 
necessary, or even possible, to resolve the debate over what Congress 
may or may not have silently intended, given the clear statutory 
language in section 112(c)(1) and 112(c)(9). The plain language of 
section 112(c)(1) explicitly states that nothing in that subsection ``* 
* * limits the Administrator's authority to establish subcategories 
under this section, as appropriate[,] * * *'' and given that Congress 
created express authority to delist categories and subcategories under 
section 112(c)(9) when the specified risk-based criteria are satisfied, 
it is clearly appropriate for EPA to establish categories and 
subcategories in a way that best enables the use of the authority 
provided by section 112(c)(9) when the agency identifies source groups 
that demonstrate they present no risks above the enumerated criteria. 
Any other interpretation of the statutory language would unnecessarily 
restrict the broad discretion that the CAA provides for this purpose. 
We, therefore, agree with the commenters who stated that section 112, 
especially when taken as a whole, provides ample authority for EPA's 
risk-based approach in the 2004 final PCWP NESHAP.
    Comment: Two commenters stated that section 112(d) of the CAA 
clearly establishes a two-step process for addressing HAP emissions 
through the MACT and residual risk provisions and that the risk-based 
exemptions contained in the PCWP MACT are contrary to the CAA.
    One commenter stated that risk-based exemptions are contrary to the 
concept of the ``level-playing field'' that should result from the 
proper implementation of technology-based MACT standards. The commenter 
also noted that the National Air Toxics Assessment (NATA) information 
shows the need for a nationwide technology-based approach and indicates 
that HAP exposure is very high throughout the entire country in both 
densely populated urban areas and remote rural locations.
    Response: We disagree that inclusion of a low-risk subcategory in 
the final PCWP rule is contrary to the 1990 CAA Amendments. The PCWP 
MACT are technology-based standards developed using the procedures 
dictated by section 112 of the CAA. The only difference between the 
final PCWP rule and other MACT rules is that we used our discretion 
under CAA section 112(c)(1) and 112(c)(9) to subcategorize and delist 
low-risk affected sources, in addition to fulfilling our duties under 
CAA section 112(d) to set MACT. It is clear from the statutory language 
that, once EPA has listed a source category under section 112(c)(1), it 
is then faced with the decision whether to regulate the source category 
under section 112(d) or to delist it under section 112(c)(9). In light 
of the authority provided by section 112(c)(9), it is unreasonable to 
assert that once a category is listed it must in all cases be regulated 
under section 112(d)(1), since the result of a delisting under section 
112(c)(9) is that the source category is exempt from section 112 
regulation. Moreover, nothing in the statutory language suggests that 
this authority to implement section 112(c)(9) is limited by what effect 
such action may have on competition within a specific industry. Rather, 
section 112(c)(9) of the CAA requires that categories or subcategories 
meet specific risk criteria in order to be delisted, and to determine 
this, risk analyses may be used. We disagree with the commenter that we 
must wait for implementation of CAA section 112(f) before utilizing 
risk analysis in this manner, since nothing in section 112(c)(9) 
suggests that its authority may not be used until after application of 
technology-based standards under section 112(d). The 2004 final PCWP 
NESHAP are particularly well-suited for a risk-based option because of 
the specific HAP that are emitted by PCWP sources. For many affected 
sources, the HAP are emitted in amounts that pose little risk to the 
surrounding population. However, the cost of controlling these HAP is 
high

[[Page 8346]]

and may not be justified by environmental benefits for these low-risk 
affected sources. Only those PCWP affected sources that demonstrate 
that they are low-risk are eligible for inclusion in the delisted low-
risk subcategory. The criteria included in the 2004 final PCWP NESHAP, 
as amended by today's final rulemaking, defining the delisted low-risk 
subcategory are based on sufficient information to develop health-
protective estimates of risk and will protect human health and the 
environment.
    We agree that one of the primary goals of developing a uniform 
national air toxics program under CAA section 112 of the 1990 CAA 
amendments is to establish a ``level playing field,'' where 
appropriate. We do not agree, however, that this goal limits our 
broader authority under section 112(c)(1) and (9), and we do not feel 
that defining a low-risk subcategory in the PCWP NESHAP does anything 
to remove the level playing field for PCWP facilities. The PCWP NESHAP 
and its criteria for demonstrating eligibility for the delisted low-
risk subcategory apply uniformly to all PCWP facilities across the 
nation. The PCWP NESHAP establishes a baseline level of emission 
reduction or a baseline level of risk (for the low-risk subcategory). 
All PCWP affected sources are subject to these same baseline levels, 
and all facilities have the same opportunity to demonstrate that they 
are part of the delisted low-risk subcategory. Therefore, concerns 
regarding facilities moving to areas of the country with air toxics 
programs that are less-stringent than today's PCWP NESHAP should be 
alleviated.
    Although NATA may show measurable concentrations of toxic air 
pollution across the country, these data do not suggest that PCWP 
facilities that do not contribute to the high exposures and risk should 
be included in MACT regulations, notwithstanding our authority under 
CAA section 112(c)(9). Our decisions regarding whether a source has 
demonstrated its eligibility for inclusion in the low-risk delisted 
subcategory will be based on whether the risks from that particular 
source, as proven by its specific facts, are within our pre-established 
criteria that are based on the statutory levels defining when a source 
category or subcategory may be delisted.

B. Background Pollution and Co-Located Emission Sources

    Comment: One commenter stated that many of the HAP emitted from 
PCWP facilities are found ubiquitously in U.S. ambient air and, 
therefore, a risk assessment methodology that ignores background 
pollution (including co-located sources) underprotects. The commenter 
noted that the 2003 proposal notice recognized that simply ensuring 
that the risks caused by PCWP sources themselves were below a hazard 
index (HI) of one (without accounting for other sources of exposure) 
would be underprotective. However, in the final PCWP NESHAP, EPA 
decided to use an HI of 1.0, but did not require sources to account for 
background pollution or emissions from co-located sources, thus failing 
to ensure that sources are truly low-risk. Two other commenters noted 
that the final PCWP NESHAP limits the analysis of risk to the impact of 
selected emissions units, but the major-source status of a source is 
based on facilitywide emissions.
    Other commenters argued that EPA correctly refrained from 
considering risks from background ambient HAP concentrations and from 
co-located sources. One commenter also noted that EPA selected a very 
conservative HI of 1.0, which builds in a margin of safety in the event 
that exposure to background sources of HAP increases the risk to public 
health. Therefore, EPA has in a way accounted for background and co-
located source emissions in formulating the low-risk subcategory. The 
commenter added that CAA section 112(d) and 112(c)(9) address source 
categories established pursuant to CAA section 112(c)(1) without regard 
to background or co-located sources outside the source category.
    Another commenter added that CAA section 112(c)(9)(B) delisting 
criteria pertaining to both threshold and non-threshold HAP are focused 
solely on exposures attributed to the affected source in question. The 
commenter believes the statutory criterion in CAA section 
112(c)(9)(B)(i) is clearly defined (one in a million cancer risk) and 
is to be evaluated solely with reference to the emissions from affected 
sources, not background concentrations. The commenter believes that 
``ample margin of safety'' delisting criterion for threshold HAP in CAA 
section 112(c)(9)(B)(ii) is more than adequately achieved by the 
combined conservatism of the dose/response assessment (inherent in the 
derivation of the reference concentration (RfC) or other inhalation 
benchmark) and the exposure assessment (inherent in the dispersion 
modeling methodology and the assumption of continuous exposure to the 
maximum average annual emissions for the duration of a lifetime).
    Response: We do not believe that it is necessary or appropriate to 
consider background HAP concentrations or HAP emissions from co-located 
sources in implementing our authority to delist the low-risk PCWP 
subcategory. After reviewing the comments and reconsidering the 
relevant sections of the CAA, we agree with the commenters who argued 
that section 112(c)(9) decisions may be based on risk assessments that 
focus on the emissions from the affected source and are not required to 
consider co-located source emissions or background concentrations. The 
residual risk program may consider, as appropriate, risks from co-
located source emissions and risks from total emissions from a 
particular location. This approach is reiterated in the recently 
finalized Coke Oven Batteries Residual Risk rule 70 FR 19991 (April 15, 
2005), where we said we will only consider emissions from the regulated 
source category when determining acceptable risk during the first step 
of the residual risk analysis. However, during the second step, where 
we determine the ample margin of safety considering costs and technical 
feasibility (70 FR 19997-98), we may consider co-located sources and 
background levels where appropriate. Additionally, the national 
strategy for area sources will address emissions from multiple sources 
in urban areas.
    Comment: One commenter contended that the authors of the MACT and 
delisting provisions at issue made clear that they intended all co-
located sources of HAP to be included when EPA made risk-based 
decisions. The commenter provided examples of legislative history of 
the 1990 CAA amendments which the commenter believes explains 
Congressional intent in crafting section 112(c)(9).
    Another commenter contended that Congress intended EPA to focus 
only on the source in question, and provided examples from the 
legislative history of CAA section 112(d)(4), which according to the 
commenter is an analogous provision. The commenter argued that Congress 
was clear when it intended for EPA to consider background 
concentrations and contributions from all sources. The commenter 
provided examples from the CAA and judicial precedent.
    Response: While we believe that under section 112(f) we may 
consider, as appropriate, co-located source and background emissions 
when conducting residual risk reviews, after reviewing the comments and 
the different statutory language in section 112(c)(9), we do not 
believe it is necessary or appropriate to consider emissions except 
those from the affected source category or subcategory at issue. This 
is because the specific language of section 112(c)(9), compared to that 
in section

[[Page 8347]]

112(f), indicates that the focus of a delisting action should be on the 
risks presented by the emissions from the affected source category or 
subcategory itself, rather than from other sources.
    The criteria for a delisting decision regarding a source category 
that emits carcinogens are discussed in section 112(c)(9)(B)(i) in a 
way that suggests EPA is to start its analysis by first identifying the 
sources ``in'' (i.e., the process units that make up the affected 
source) the source category, and determine whether HAP ``emitted by'' 
such affected sources ``in'' the category exceed quantities that cause 
a lifetime cancer risk greater than one-in-one million to the 
individual who is most exposed to emissions of ``such pollutants from 
the source[.]'' This focus on emissions from sources that are actually 
within the source category as being the scope of HAP concentrations 
that must not exceed the enumerated cancer risk benchmark would be 
frustrated by an analysis that imports HAP emissions from other sources 
not in the source category, or that includes background HAP 
concentrations that may not be attributable to any source at all.
    Similarly, section 112(c)(9)(B)(ii) provides that for non-
carcinogen HAP, EPA is to assess whether emissions ``from no source in 
the category or subcategory'' exceed a level adequate to protect public 
health and whether emissions ``from any source'' in the subject 
category or subcategory will cause an adverse environmental effect. 
Again, the statutory language focuses on the emissions that are 
attributable to sources within the source category or subcategory under 
review, and does not direct EPA to extend its analysis to either 
emissions from other sources in other categories or subcategories or to 
non-attributable background concentrations.
    Contrast this with the language of section 112(f)(2)(A), which, 
initially, directs EPA to determine whether further risk-based 
standards are required in order to provide an ample margin of safety to 
protect public health to prevent an adverse environmental effect, 
without specific reference as in section 112(c)(9)(B)(i) and (ii) to 
the emissions from sources within the source category in question. This 
difference alone suggests that EPA may take a broader look in assessing 
risks under section 112(f) than is required under section 112(c)(9). 
Moreover, in establishing the trigger for when EPA is required to adopt 
residual risk standards, section 112(f)(2)(A) focuses on the lifetime 
excess cancer risk to the individual most exposed to emissions from 
sources in the subject category or subcategory, but does not, like in 
section 112(c)(9)(B)(i), clearly indicate that the excess cancer risk 
is to be that caused only from the emissions from the sources within 
the subject source category. Rather, under the language of section 
112(f)(2), EPA may consider the cancer risk experienced by the most 
exposed individual, whatever the source or sources of that risk may be, 
and then regulate if the subject source category contributes to that 
risk. A similar analysis applies to section 112(f)(2)(A)'s directive to 
assess whether further standards are necessary to prevent an adverse 
environmental effect, which, unlike the language in section 
112(c)(9)(B)(ii), does not specifically state that such effect must be 
caused by emissions from the sources in the subject source category. 
Finally, the language in section 112(f)(2)(A) that establishes the 
threshold of protection residual risk standards must achieve also does 
not explicitly limit EPA's authority to focusing only on the emissions 
from the affected sources in the subject category.
    Therefore, while both section 112(f)(2) and 112(c)(9) use the 
phrase ``ample margin of safety'' to define the triggers for action 
and/or the benchmark that must be met in action, the differences in 
additional contextual language in the two subsections makes it 
reasonable to interpret section 112(c)(9) as allowing a more narrowly 
focused risk assessment for source category and subcategory delistings 
than the agency has stated it intends to pursue in residual risk, in 
which we have asserted the ability to evaluate ``other relevant 
factors'' beyond those presented by the affected source (70 FR 19998).
    Comment: One commenter stated that if the final PCWP rule 
incorporates risk-based exemptions, sources included in the low-risk 
subcategory should not be exempted from consideration during the 
residual risk process. Other commenters argued that EPA does not have 
authority to consider facilitywide or background emissions in residual 
risk determinations.
    Response: We disagree that we do not have the authority to include 
the entire facility in our residual risk analyses. In the preamble to 
the coke ovens residual risk rule, we reiterated our discretion to 
include, as appropriate, emissions from outside the source category 
during the ample margin of safety determination. The emissions 
evaluated during this ample margin of safety determination can include 
those from PCWP sources that are part of the low-risk subcategory.

C. Ecological Risk

    Comment: Two commenters stated that the risk-based exemptions in 
the PCWP rule do not address ecological risks that may result from 
uncontrolled HAP emissions. One of the commenters believes that EPA's 
ecological assessment for the final rule is fundamentally inadequate. 
The commenter believes EPA failed to meet the legal requirement in the 
CAA in several obvious ways: (1) The assessment focused on just a few 
HAP and thus ignored potential environmental impacts from other 
emissions; (2) by evaluating a single location, the assessment ignored 
potential site-specific environmental receptors and locally affected 
species; and (3) the consideration of only persistent and 
bioaccumulative HAP would not capture potential acute effects on the 
environment.
    To the contrary, one commenter believes that EPA properly evaluated 
ecological risks. The commenter referred to their study of ecological 
risks which the commenter believes concurs with EPA's findings that no 
potential adverse risk to ecological resources is likely based on the 
available data.
    Response: To determine whether low-risk PCWP sources are likely to 
cause adverse environmental effects due to HAP emissions, EPA performed 
a screening assessment of ecological risks from these sources. The 
ecological assessment focused on HAP that are emitted by PCWP 
facilities and that have the potential to persist in the environment 
and bioaccumulate. The list of persistent and bioaccumulative HAP (PB 
HAP) is described in EPA's Air Toxics Risk Assessment (ATRA) Reference 
Library (http://www.epa.gov/ttn/fera/risk_atra_main.html). We did not 

evaluate inhalation risks of non-PB HAP to ecological receptors 
explicitly. Rather, we assert that the acute and chronic dose-response 
values for human inhalation exposure, which will be used by PCWP 
facilities to demonstrate their low-risk status, are protective of 
inhalation exposures that may be experienced by many terrestrial 
animals. Human dose-response values are derived from studies that 
consider human data and data from laboratory animals. With the addition 
of uncertainty factors, the final dose-response values are generally 
substantially lower than the level observed to cause an adverse effect 
in exposed animals. Therefore, if the maximum inhalation hazard to 
humans, which is the major basis for the LRD, is below the level of 
concern, we do not expect adverse effects on environmental

[[Page 8348]]

receptors due to inhalation exposures. For the HAP that must be 
included in PCWP LRD, and for which ecological inhalation toxicity 
values are readily available, the human inhalation dose-response values 
are protective for inhalation exposures to ecological receptors when a 
hazard quotient or HI of 1.0 is used. For the details of this 
comparison see the memo titled, ``Comparison of ecological inhalation 
toxicity values to human health inhalation toxicity values for HAP that 
must be considered in Low-Risk Demonstrations (LRDs) from sources in 
the Plywood and Composite Wood Products (PCWP) source category''.
    For the assessment of persistent or bioaccumulating HAP, we made 
several ecosystem-protective assumptions. We derived estimated worst-
case media concentrations by assuming the maximum air concentrations 
and the maximum deposition rates occurred at the same location, 
although this is often not the case. We examined six locations 
representing diverse meteorological conditions, and for the final 
assessment, we used the location providing the highest predicted HAP 
concentrations. We used the most conservative ecological screening 
values readily available, which may overestimate the potential for 
toxicity to site-specific populations and communities. Finally, we 
assumed 100 percent bioavailability of the HAP, although site-specific 
bioavailability is often much less. The results of our ecological 
assessment demonstrate that for all pollutants assessed, and for all 
pathways assessed, the ecological hazard quotient values are less than 
1. The highest hazard quotient is 0.043, or more than 20 times below a 
level of potential concern. Given this result, and the ecosystem-
protective nature of the assessment scenario, we do not believe that 
HAP emitted from PCWP facilities will harm local ecosystems. Therefore, 
we conclude that HAP emissions from any source that demonstrates 
eligibility to join the low-risk PCWP subcategory will not cause an 
adverse environmental effect.

D. The Dose-Response Value Used for Formaldehyde

    Comment: One commenter noted that in proposing the risk-based 
exemption idea, EPA indicated that it would use unit risk estimates 
(UREs) from EPA's Integrated Risk Information System (IRIS) to 
calculate whether or not a given source is low-risk. However, in the 
final rule, EPA relied on a much lower value derived by the CIIT 
Centers for Health Research (CIIT)(previously the Chemical Industry 
Institute of Toxicology) using a model that estimated the carcinogenic 
effects of formaldehyde on the respiratory system.
    Several commenters recommended that EPA continue to use the IRIS 
potency factor for formaldehyde until EPA has completed its thorough 
review process (including public review) and updated IRIS. The 
commenters stated that adopting a factor that has not undergone the 
full IRIS review process jeopardizes public health. The commenters 
recommended that EPA accelerate completion of the IRIS review.
    To the contrary, one commenter believes that EPA properly evaluated 
the carcinogenicity of formaldehyde by abandoning the outdated and 
scientifically inaccurate IRIS value and instead relying on evidence 
that has received broad acceptance in the international scientific 
community. The commenter also believes that IRIS is far from 
definitive, as EPA resource constraints have resulted in many chemical 
summaries that are significantly outdated. The commenter contended that 
EPA management has repeatedly emphasized that EPA is required to 
consider other information, in addition to the IRIS database, when 
evaluating the health effects of chemicals in a regulatory context.
    Response: We agree with the first commenters that we should use the 
best available sources of health effects information for risk or hazard 
determinations. As we have stated previously, we do not rely 
exclusively on IRIS values. Rather, we consider all credible and 
readily available assessments.\2\ For air toxics risk assessments, we 
identify pertinent toxicity or dose-response values using a default 
hierarchy of sources, with IRIS being the preferred source, to assist 
us in identifying the most scientifically appropriate benchmarks for 
our analyses and decisions. The IRIS process contains a peer-review 
process, and the resulting values represent EPA consensus. When 
adequate toxicity information is not available in IRIS, we consult 
other sources in a default hierarchy that recognizes the desirability 
of review and consistency with EPA risk assessment guidelines. This 
process ensures that we have consistent and scientifically sound 
assessments. Furthermore, where the IRIS assessment is relatively dated 
and newer peer-reviewed assessments are available, we will consider the 
full set of such assessments in selecting the basis for the risk 
assessment. In the case of formaldehyde, we have determined that the 
cancer potency derived using the approach developed by CIIT, which has 
been peer reviewed by an external review panel sponsored by EPA and the 
Canadian government, represents an appropriate alternative to EPA's 
current IRIS URE for formaldehyde. Therefore, this potency represents 
the best available peer-reviewed science at this time. We also agree 
with the last commenter that the issue of changing health-based 
guideline values is a general challenge in setting health-based 
regulations. However, we are committed to setting such regulations that 
reflect current scientific understanding, to the extent feasible. If 
dose-response values change, PCWP sources in the low-risk subcategory 
must ensure that they continue to meet the low-risk requirements in 
appendix B to subpart DDDD using the revised values. If PCWP sources no 
longer meet those low-risk criteria due to a change in a peer-reviewed 
dose-response value selected by the Agency for those assessments, that 
source must comply with the technology standards of the PCWP MACT. 
Facilities conducting LRD should refer to appendix B to subpart DDDD of 
40 CFR part 63 for guidance on choosing appropriate dose-response 
values.
---------------------------------------------------------------------------

    \2\ U.S. Environmental Protection Agency. 1999. Residual Risk 
Report to Congress. Office of Air Quality Planning and Standards, 
Research Triangle Park, NC 27711, March 1999, EPA-453/R-99-001; 
available at http://www.epa.gov/ttn/oarpg/t3/meta/m8690.html. (EPA 

1999)
---------------------------------------------------------------------------

    Comment: Several commenters submitted in-depth comments relating to 
the CIIT report and carcinogenicity of formaldehyde. Some commenters 
argued that the CIIT model for carcinogenic potency of formaldehyde is 
limited in a number of ways, and needs further validation and peer 
review. The commenters described recent epidemiological studies that 
reportedly link formaldehyde exposure to leukemia. Other commenters 
believe that EPA correctly evaluated the formaldehyde cancer potency 
value for the final rule and stated that the CIIT risk assessment is 
the best available science. The commenters disagreed that the 
availability of new scientific studies justifies use of the outdated 
IRIS value and argued that the new studies are flawed.
    Response: As mentioned above, we are committed to using the best-
available science for our risk assessments. In situations where the 
IRIS assessment lags behind current scientific knowledge and newer 
peer-reviewed assessments are available, we will consider the full set 
of such assessments in selecting the basis for the risk assessment. 
These alternatives need to be grounded in publicly-available,

[[Page 8349]]

peer-reviewed information. In the case of formaldehyde, we have 
determined that the cancer potency derived using the approach developed 
by CIIT and peer-reviewed by an independent expert peer review panel 
sponsored by EPA and the Canadian government represents an appropriate 
alternative to EPA's current IRIS URE for formaldehyde, and is 
therefore the best-available peer-reviewed science at this time. 
However, we note that a comprehensive reassessment of cancer risk has 
been initiated for IRIS. This reassessment will include modeling 
analyses and endpoints (e.g., lymphohematopoietic cancer) not 
considered in the CIIT assessment. We expect the IRIS reassessment to 
be completed in 2007. The revised IRIS assessment will represent the 
best-available peer-reviewed science at the time of its completion and 
we will require LRD to use the revised URE that results from the 
reassessment process.

E. Appendix B to 40 CFR Part 63 Subpart DDDD Requirements

1. Average Stack Heights
    Comment: One commenter stated that the promulgated risk assessment 
methodology allows a source to use average stack heights, which 
decreases the accuracy of the risk assessment and may significantly 
understate the risks from any given source. The commenter stated that 
EPA's proposal to incorporate a weighted stack height for the look-up 
tables only exacerbates the problem. The commenter predicted that 
sources will only use the weighted stack height when it is to their 
advantage.
    Other commenters stated that the values in the look-up tables and 
the use of average stack heights are not health protective under worst-
case conditions. The commenters stated that dispersion is a non-linear 
function and it is impossible to try and simplify the effects of a 
stack. For example, the impact of a 40-foot stack is not one half the 
impact of a 20-foot stack. In fact, depending on the building heights 
and the distance to the receptor, the impact of the taller stack could 
be similar to the shorter one.
    One commenter disagreed that use of average stack heights where 
there are multiple emissions points may significantly understate risks. 
The commenter pointed out that the LRD requires sources to use the 
shortest distance to the property boundary, coupled with the average 
stack height. The commenter believes that use of the shortest distance 
to the property boundary would more than compensate for any 
underestimates in exposure in any unlikely instances where lower 
emitting sources have the taller stacks.
    Two commenters supported EPA's proposal to replace the average 
stack height calculation for the look-up tables in appendix B to 
subpart DDDD with a separately computed toxicity-weighted stack height 
corresponding to each of the three health effects. One commenter noted 
that the large majority of emissions from wood products facilities 
occur through relatively tall stacks. However, wood products facilities 
also have many very low-emitting emission points that are quite close 
to the ground. As promulgated, the rule requires these low-emitting 
near-ground emission points to be averaged with the higher-emitting 
stack emission points to develop an average stack height that 
understates actual stack heights. Therefore, the promulgated approach 
results in an overly conservative estimation of actual stack height 
which, coupled with the conservative assumption of using the shortest 
distance to the property boundary and the other elements of 
conservatism built into the look-up tables, goes beyond what is needed 
to protect human health with an ample margin of safety. The commenter 
stated that the proposed toxicity-weighted stack height approach 
addresses this issue in a reasonable and appropriate manner.
    Another commenter agreed, arguing that assuming all emissions occur 
at the location of the stack with the minimum distance to the property 
boundary is unnecessarily conservative. The commenter recommended that 
an appropriate average property boundary distance be calculated using 
the same toxicity-weighted averaging procedure suggested for stack 
height.
    Response: We agree that the average stack height is not the best 
metric for characterizing risks in a look-up table analysis. Appendix B 
to subpart DDDD now requires the calculation of a toxicity and 
emissions-weighted stack height for the look-up table analysis. Using 
this approach, the emission points with the highest toxicity-weighted 
emission rate will contribute the most to the stack height calculation 
while the emission points with the lowest toxicity-weighted emission 
rate will contribute the least. Thus, the weighted stack height metric 
provides a more accurate characterization of a source's emissions 
characteristics and it addresses commenters' concerns about under-
predicting risks for sources with most emissions coming from the 
shortest stacks. Further, using this more precise method does not 
undercut our reliance on other health-protective assumptions in the 
look-up table analysis when most of the emissions come from taller 
stacks.
    Use of weighted stack height is not optional, but is required for 
facilities performing the look-up table analysis in their LRD. We 
proposed to replace the average stack height calculation with the 
weighted stack height calculation.
    Contrary to one commenter's statement, we do not assume dispersion 
to be linear with stack height. Rather, the allowable emission rates in 
the look-up tables are based on actual dispersion model runs using the 
stack heights given in the table. Additionally, we agree that 
collapsing across multiple stacks to generate a single weighted stack 
height will not result in the exact same model output as if each stack 
is modeled separately. However, use of the weighted stack height is a 
simplifying step that is not expected to be consistently more or less 
health-protective than modeling each stack separately. Because the 
look-up table analysis is designed to be simple and because several 
inputs to the tables bias them toward overestimating risks for most 
sources, using a weighted stack height is appropriate in this context. 
We agree with the commenter that, in cases where stacks are located on 
top of buildings, building height can impact dispersion and risk. 
Therefore, appendix B requires that when sources determine their stack 
heights, they must use the height of the stack above the ground. 
Therefore, if a stack is located on top of a building, that building 
height is incorporated into the stack height value. We also agree with 
the commenter that receptor location impacts risks. A look-up table 
analysis inherently incorporates health-protective assumptions 
regarding receptor location. The allowable emission rates in the look-
up tables are based on the maximum predicted offsite pollutant 
concentrations, regardless of whether that site is populated. 
Additionally, sources must use the shortest distance between an 
emission point and the property boundary when conducting a look-up 
table analysis. Therefore, sources using the look-up tables must assume 
that all HAP emissions are coming from the emission point closest to 
their property boundary, that people live at the location of maximum 
predicted pollutant concentration, and that they remain at that 
location for a lifetime. This approach is more health-protective than 
if actual facility configuration and/or the location of actual 
populations were to be considered.
    We also disagree with changing the minimum distance to property 
boundary. We recognize that using the

[[Page 8350]]

minimum distance to property boundary may overestimate the ambient 
concentration and exposure. However, the lookup table analysis is meant 
to be health-protective and using the minimum distance to property 
boundary helps ensure that this is the case.
2. HAP With No Health Benchmarks
    Comment: One commenter stated that the promulgated risk assessment 
methodology fails to account for all HAP emitted by PCWP sources, 
omitting some HAP like propionaldehyde, one of the ``predominant'' HAP 
emitted by PCWP sources. The commenter noted that EPA's methodology 
would assign a zero cancer risk to any HAP for which EPA has yet to 
estimate such a value, even if such HAP may well be carcinogenic.
    One commenter stated that six HAP (acrolein, acetaldehyde, 
formaldehyde, methanol, phenol, and propionaldehyde) make up 96 percent 
of the emissions from wood products facilities. The only one of these 
chemicals lacking a health benchmark is propionaldehyde. The commenter 
stated that EPA could extrapolate a propionaldehyde health benchmark 
from occupational exposure limits. Even using the resulting health 
benchmark, the commenter's analysis has demonstrated that 
propionaldehyde makes no meaningful contribution to individual source 
risk.
    The commenter noted that EPA conducted a preliminary analysis of 
the risks associated with PCWP facilities which narrowed the substances 
considered to eight HAP, suggesting that the other HAP either were not 
emitted from these facilities or were emitted in such low levels as to 
not be meaningful contributors to risks in the source category. The 
commenter referred to a sensitivity analysis they commissioned and 
stated that the available data indicate that pollutants without health 
benchmarks do not have the potential to influence risk results for wood 
products industry. Accordingly, the commenter believes that EPA was 
justified in not requiring sources to consider the potential risks of 
pollutants emitted by wood products facilities that do not have health 
benchmarks.
    The commenter disagreed that EPA has acted arbitrarily in assuming 
zero cancer risk for HAP for which it has yet to estimate such a value. 
The commenter noted that the petitioners want EPA to assume that all 
chemicals for which EPA has not set a cancer potency value are 
carcinogenic. The commenter believes the petitioners' approach would 
prevent EPA or any regulatory agency from ever making any realistic or 
meaningful evaluation of potential risks (in any context) and would 
merely serve to confuse (and scare) the public by suggesting that 
sources pose cancer risks when in fact they do not.
    Response: We are committed to using the best science available for 
our risk assessments. To maintain this standard, we are using the 
default hierarchy of sources for cancer and non-cancer dose-response 
values that was originally developed for EPA's National-Scale Air 
Toxics Assessment (http://www.epa.gov/ttn/atw/nata/natsa4.html). When 

developing this hierarchy, we considered conceptual consistency with 
EPA risk assessment guidelines and the level of review incorporated 
into the dose-response values from each source. The EPA's IRIS process 
is the preferred source of dose-response values. When IRIS values are 
not available, we consider the alternative sources in our hierarchy. 
Additionally, in cases where the IRIS value lags behind the scientific 
literature, we are committed to considering alternative, credible dose-
response values. Currently, we do not have an IRIS file for 
propionaldehyde, and an assessment is not available from the 
alternative sources in our hierarchy. However, appendix B to subpart 
DDDD requires sources to update their risk assessments if parameters, 
including dose-response values, change in a way that could increase 
risks. Therefore, if an acceptable cancer potency or non-cancer 
reference value for propionaldehyde becomes available, we will consider 
whether this HAP should be included in risk assessments for PCWP 
sources. One commenter suggested that we use a modified occupational 
exposure limit for propionaldehyde. In the past we have modified 
toxicity values developed for other purposes so that they can be used 
for inhalation assessments that support non-regulatory, screening 
applications. However, because in the present case the modified 
exposure limit would be used to make regulatory decisions, such a dose 
conversion is inappropriate, particularly in the absence of scientific 
peer-review.
    We agree that it is appropriate to limit the number of HAP that 
must be included in PCWP affected source LRD to only those HAP that may 
possibly result in meaningful contributions to the affected source 
risk. However, we are not limiting the HAP included in the LRD to the 
six HAP defined as total HAP in subpart DDDD of 40 CFR part 63 
(acrolein, acetaldehyde, formaldehyde, methanol, phenol, and 
propionaldehyde). We identified the most prevalent HAP based on mass 
emitted for purposes of developing MACT compliance options because MACT 
is technology-based (i.e., the same technology that reduces emissions 
of the six HAP also reduces emissions of other organic HAP). The six 
HAP defined as total HAP in subpart DDDD of 40 CFR part 63 are the HAP 
that are most often emitted in detectable amounts from the most PCWP 
process units, and these HAP make up 96 percent of the mass of 
nationwide HAP emissions from the PCWP industry. However, the risks 
associated with emissions of HAP are dependent on the mass emitted and 
the relative toxicity of each HAP. Thus, the HAP emitted in the 
greatest mass may not result in the most risk because the HAP may not 
be as potent as other HAP emitted in lower mass. For example, methanol 
is the HAP emitted from the PCWP industry in the greatest mass, but 
because methanol is not as toxic as other HAP emitted (e.g., 
formaldehyde, certain HAP metals), it does not result in as much risk 
as do other HAP.
    The commenter is correct in that our preliminary risk analysis 
conducted prior to proposal of the PCWP rule narrowed the list of HAP 
emitted from PCWP affected sources. We acknowledge receipt of the 
commenter's sensitivity analysis based on the data used in our pre-
proposal risk analysis. Following proposal, we conducted a more 
detailed risk analysis to evaluate the merits of including a low-risk 
subcategory in the final PCWP rule. This memo is available in the 
docket and is titled, Risk Assessment for the Final Maximum Achievable 
Control Technology (MACT) Rule for the Plywood and Composite Wood 
Products (PCWP) Source Category. This post-proposal analysis considered 
emissions of more than 30 HAP emitted from the PCWP source category. 
Many of these HAP are only emitted in minute amounts that have been 
detected from a small number of PCWP process units. Nevertheless, we 
included them in our risk analysis to determine their contribution to 
PCWP affected source risk. We reviewed the toxicity values for each HAP 
and the mass of each emitted from PCWP affected sources to determine if 
it would be appropriate to narrow the list of HAP that PCWP affected 
sources must consider in their LRD. Based on our review, we determined 
that 95 percent of the cancer risk at PCWP affected sources is 
accounted for by the following HAP: acetaldehyde, benzene, arsenic, 
beryllium, cadmium, hexavalent

[[Page 8351]]

chromium, lead, nickel subsulfide, and formaldehyde. We also determined 
that 95 percent of the non-cancer risk at PCWP affected sources is 
accounted for by the following HAP: acetaldehyde, acrolein, 
formaldehyde, phenol, MDI, arsenic, cadmium, and manganese. We feel 
that inclusion of these HAP in a demonstration of eligibility of the 
low-risk PCWP subcategory is appropriate. Limiting the list of HAP that 
must be included in the LRD to 13 HAP minimizes emissions testing 
costs, while ensuring that the HAP that drive the risk at PCWP affected 
sources are accounted for on a site-specific basis.
3. Topography and Weather Patterns
    Comment: One commenter stated that EPA's methodology treats all 
PCWP plants as though their local topography and climate are identical 
and that factors like prevailing winds are ignored. The commenter 
believes the risk assessment methodology should account for topography 
since different topographical features may exacerbate HAP exposures. 
The commenter stated that PCWP plants are located at widely varying 
altitudes and attached a chart.
    One commenter stated that the modeling behind the development of 
the look-up table should consider downwash. Another commenter stated 
that facilities in areas with complex terrain should not be allowed to 
use the look-up tables because the assumptions used to develop the 
look-up table could not possibly account for this scenario. The 
commenter expressed concern that the look-up tables do not account for 
the common use of rain caps and for the likely event of building 
downwash.
    One commenter disagreed that EPA's look-up tables fail to account 
for topography and weather patterns. To the contrary, the commenter 
noted that EPA made conservative assumptions (e.g., minimum fence line 
distance, worst-case meteorology, safety factors built into RfCs and 
UREs, and the assumption that plumes from all sources directly 
overlap), such that the look-up tables would be more likely to 
overestimate (rather than underestimate) actual risk. One commenter 
stated that it is unlikely that consideration of terrain will 
substantially affect the screening risk emission levels, given that 
most PCWP facilities are located in areas characterized by flat or 
gently rolling terrain.
    Response: We disagree that we have not considered site-specific 
differences between sources in the methodology of appendix B to subpart 
DDDD. If sources conduct site-specific risk assessments, they should 
either use site-specific data, including for meteorological and 
topographical information, or they should use health-protective 
defaults. For look-up table analyses, we have made a number of health-
protective assumptions, including worst-case meteorological conditions. 
Therefore, even though the look-up tables treat all sources as if they 
have the same meteorology, that default meteorology should result in 
higher predicted risks than actual site-specific meteorology.
    However, we do not agree that the protective measures inherent in 
the look-up tables justify their use in all cases. As several 
commenters identified, we recognize that site-specific factors such as 
building downwash, the presence of rain caps, and complex terrain were 
not accounted for in the SCREEN3 dispersion modeling used to create the 
look-up tables. In situations where these factors can have a 
significant impact on the risks presented by a source, we agree that 
use of the look-up tables is not appropriate. Where we determine, 
during the risk assessment review process, that the look-up tables are 
inappropriate, sources would be required to demonstrate eligibility 
using a site-specific risk assessment. If a source is unable to make 
this demonstration, the source must then comply with the technology 
standards in the MACT.
4. Children's Health Risk
    Comment: One commenter stated that EPA's risk assessment 
methodology does not adequately account for the sensitivities of 
children to environmental stressors because the methodology relies on 
pre-existing cancer potency estimates which are deficient with respect 
to early-life exposures.
    However, another commenter believes that EPA's cancer potency 
factors are amply conservative to protect against potential childhood 
cancer risk. The commenter stated that the unit risk factor (URF) is 
specifically based on worst-case assumptions (i.e., linear multistage 
model for calculating the URF and through the assumption that a person 
will be continuously exposed for a lifetime).
    Response: The EPA has issued revised Guidelines for Carcinogen Risk 
Assessment (Guidelines) and also Supplemental Guidance for Assessing 
Susceptibility from Early-Life Exposure to Carcinogens (Supplemental 
Guidance) which deal specifically with assessing the potential added 
susceptibility from early-life exposure to carcinogens. The 
Supplemental Guidance provides an approach for adjusting risk estimates 
to incorporate the potential for increased risk due to early-life 
exposures to chemicals that are concluded to be carcinogenic by a 
mutagenic mode of action. For these chemicals, the supplemental 
guidance indicates that, in lieu of chemical-specific data on which age 
or life-stage specific risk estimates or potencies can be based, 
default age-dependent adjustment factors can be applied when assessing 
cancer risk for early-life exposures. As EPA's hazard and dose-response 
assessments are updated under the new Guidelines and Supplemental 
Guidance, they will include consideration of the available information 
with regard to mode of action and the potential for this determination. 
Thus, when estimating cancer risks for the purposes of this regulation, 
the current HAP-specific assessments must be consulted to obtain both 
the current inhalation unit risk values and the determination as to 
mode of action. Where EPA's assessment has determined that the chemical 
is carcinogenic by a mutagenic mode of action, it is recommended that 
the risk assessment developed for the purposes of this regulation 
employ applicable life-stage specific potencies or age dependent 
adjustment factors per the Supplemental Guidance when early life 
exposure is expected to occur.
5. Distance to Nearest Residence
    Comment: Commenters noted that the risk calculation depends upon 
the distance any given source is to the nearest residence, ignoring the 
possibility that there may be exposed people closer to the facility, 
such as a school, day care center, or neighboring business. One 
commenter stated that the most exposed individual is likely to be a 
person who actually works at the PCWP facility as opposed to a person 
beyond the facility fence line.
    One commenter believes EPA should revise the risk screening to use 
the distance to the property line instead of the distance to the 
nearest resident. The commenter believes that both the look-up tables 
and the site-specific screening should use the property boundary or the 
point of maximum impact for the LRD.
    A separate commenter disagreed that EPA should have required the 
site-specific assessments to evaluate continuous lifetime exposure at 
the nearest receptor (as opposed to the nearest residence), whether it 
be a school, shopping mall or church. The commenter noted that the 
promulgated PCWP rule allows risks to be computed at residential 
locations with the highest modeled risk for site-specific assessments. 
The commenter believes this is appropriate because EPA requires sources 
to assume the worst-case

[[Page 8352]]

exposure scenario (i.e., continuous, lifetime exposure for 70 years). 
The commenter noted that people would not spend 24-hours per day, 365 
days per year for 70 years at a school, shopping mall or church. 
Although this exposure scenario is equally implausible for residences, 
the commenter thinks that residential locations are a more appropriate 
choice.
    The commenter noted that the rule does not explicitly address the 
receptors that should be applied for the acute exposure assessments 
(which are required independently for acrolein and formaldehyde). The 
commenter requested that the rule clearly state that for acute 
exposures, the proper reference is to the property boundary rather than 
to the nearest residence.
    Response: In exercising our authority under section 112(c)(9), we 
do not think it is appropriate to base our determinations on risks 
presented at the PCWP facility due to occupational exposures, since 
such risks are not caused by emissions of HAP into the ambient air 
(i.e., since they are on the plant site, they are not beyond the plant 
fence line and are therefore not into the ambient air). However, we do 
agree that risks to individuals at other locations surrounding the 
source could potentially exceed risks to individuals at nearby 
residences. Therefore, we have modified appendix B to subpart DDDD to 
indicate that, in addition to residences, risk assessments should 
include consideration of other locations such as schools and day care 
facilities. We note that, as we described in EPA's ATRA Reference 
Library, sources can deviate from default exposure assumptions if they 
can provide adequate justification for the deviation. Such deviation is 
appropriate where exposure duration is limited in terms of hours per 
day, days per week, and/or total number of years.
    Look-up table assessments must use distance to property boundary, 
not distance to nearest residence. This requirement, which uses the 
point of maximum impact outside the property boundary, adds to the 
health-protection provided by look-up tables. We agree with the 
commenter that this is the preferred approach for the look-up table 
analyses. However, we disagree that site-specific risk assessments 
should be limited to the property boundary. If a site-specific risk 
assessment uses nearest residences for their risk calculations, and if 
new residences are constructed in an area of higher risk, sources must 
re-assess their risks to ensure they continue to meet the criteria in 
appendix B to subpart DDDD. If they no longer meet these criteria (e.g. 
because someone moved closer to their facility), then the source is no 
longer eligible for the low-risk subcategory. Such a source must then 
comply with the technology standards in the PCWP MACT.
    We agree that acute assessments should use the point of maximum 
impact outside the facility's property boundary. This requirement is 
stated explicitly in appendix B to subpart DDDD.
6. Criteria Included in Site-Specific Risk Demonstrations
    Comment: One commenter stated that EPA gives sources the ability to 
make source-specific demonstrations with a number of open-ended 
criteria. For instance, the commenter noted that appendix B to subpart 
DDDD allows any scientifically accepted peer-reviewed assessment 
methodology for site-specific risk assessment, and instructs sources to 
use health-protective default assumptions wherever site-specific data 
are not available. Thus, the commenter believes the facility owner has 
extreme control over how to assess its risks, and EPA provides few 
bounds on its discretion to approve such assessments as sufficiently 
scientifically accepted or health protective. Another commenter 
believes that the rule does not require that the risk assessment 
methodology be approved by any regulatory agency as scientifically 
acceptable or applicable.
    One commenter stated that the approach included in the final rule 
is consistent with general risk assessment methodologies, including 
recommendations from the National Academy of Sciences Science and 
Judgment in Risk Assessment (1994) and has been standard EPA practice 
for over a decade. The commenter noted that EPA specifies its 
preference that sources conduct their site-specific risk assessments in 
accordance with the ATRA Reference Library (Volume 2) should facilities 
not pass the initial look-up table screening analysis. Sources also 
have the option of using alternative modeling methodologies provided 
they have undergone scientific peer review. The commenter believes that 
this does not, in turn, give sources unfettered freedom, but does 
recognize that new modeling approaches may be developed in the future.
    Response: We continue to believe that providing sources with the 
discretion to use any ``scientifically-accepted, peer-reviewed risk 
assessment methodology'' (e.g., see EPA's ATRA Reference Library) is 
appropriate. However, contrary to the assertions of some commenters, 
this discretion is not unlimited. Section 7 of appendix B to subpart 
DDDD presents specific minimum criteria for site-specific low risk 
assessments. In order to demonstrate eligibility for the low-risk 
subcategory, the site-specific risk assessment conducted by the 
facility must meet the following criteria: (1) Estimate long-term 
inhalation exposures through an estimation of annual or multi-year 
average ambient concentrations; (2) estimate acute exposures for 
formaldehyde and acrolein maximum 1-hour average ambient 
concentrations; (3) estimate the inhalation exposure of the individual 
most exposed to source emissions; (4) estimate individual risks over a 
70-year lifetime for the chronic cancer risk assessment; (5) use site-
specific quality-assured data wherever possible; (6) use health-
protective default assumptions wherever site-specific data are not 
available; and (7) contain adequate documentation of the data and 
methods used so that it is transparent and reproducible. The ATRA 
Reference Library provides examples of how a risk assessment can be 
conducted. These examples include instruction in basic risk assessment 
methodology, in determining what parameters to include in a risk 
assessment, and in the constraints that should be placed on those 
parameters. The documents within the ATRA Reference Library have been 
peer-reviewed and were developed according to the principles, tools and 
methods outlined in the 1999 EPA Report to Congress. However, the 
guidance in the ATRA Reference Library may not be appropriate for all 
sources. For that reason we believe that it is important for sources to 
be able to consider alternative analytical tools as long as those 
alternatives are scientifically defensible, peer-reviewed and 
transparent per the criteria listed above. Additionally, we disagree 
with the commenter that the risk assessment methodology will not be 
approved by a regulatory agency. The EPA will be responsible for 
reviewing all PCWP risk assessments, and part of that review will 
include ensuring that an appropriate assessment methodology is used. 
The EPA may disapprove any risk assessment that fails to meet the 
criteria of appendix B to subpart DDDD.

F. Selection of Process Units and Emissions Determination Procedures in 
Table 2A to Appendix B to 40 CFR Part 63 Subpart DDDD

1. Use of Emission Factors and Other Emission Estimation Procedures
    Comment: Two commenters addressed EPA's proposed amendment to allow 
facilities to use emissions

[[Page 8353]]

factors in LRD for certain process units rather than conduct emissions 
tests. One commenter strongly supported both EPA's decision to simplify 
the calculation of emissions used in the risk assessments and the 
concept of using default emission values for relatively low emitting 
and/or hard-to-test process units because many of the process units 
included in table 2A to appendix B to subpart DDDD cannot be tested 
without research-level effort. Another commenter disagreed with the 
proposal to allow facilities to demonstrate compliance with the 
requirements of the low-risk subcategory using emissions factors and 
emissions estimates instead of conducting emissions tests. The 
commenter noted that EPA's own publications, including AP-42 and 
reports by the Office of the Inspector General, state that the use of 
emission factors for compliance purposes is inappropriate. According to 
the commenter, this proposal does not satisfy the section 112(c)(9)(B) 
requirement that EPA determine that all sources in a category emit HAP 
at levels below identified risk thresholds prior to exempting the 
category from applicable MACT standards. In addition, the approach does 
not fulfill EPA's commitment to require ``enhanced monitoring'' from 
all sources subject to a section 112 MACT standard.
    Response: Appendix B to subpart DDDD provides methodology and 
criteria for sources to demonstrate whether they are part of the 
delisted low-risk subcategory. Sources that are part of the delisted 
low-risk subcategory are not part of the PCWP source category. 
Therefore, in developing the emission factors in table 2A to appendix B 
to subpart DDDD, we used the maximum available emission rate, as 
opposed to the average emission rate, to ensure that emission estimates 
used for LRD are health protective and reasonably account for the 
uncertainty associated with using emission factors.
    Because the LRD are to be based on the cumulative risk from all 
process units within each PCWP affected source, we are requiring that 
each process unit be considered in the LRD. In developing table 2A to 
appendix B to subpart DDDD, we considered the feasibility of emissions 
testing for each type of PCWP process unit and chose to allow emission 
factors to be used for selected hard-to-test process units. We believe 
that most of the process units for which we would allow emissions 
estimates in lieu of testing are minor contributors to the total HAP 
emissions relevant to the LRD. Because sources may use only the most 
health-protective emission factors for only hard-to-test process units, 
we do not believe risk assessments will be less health protective with 
the inclusion of emission factors.
    Affected sources that are not part of the low-risk subcategory must 
comply with the MACT requirements in subpart DDDD, and subpart DDDD 
contains compliance monitoring requirements for all the process units 
with control or work practice requirements under subpart DDDD. Sources 
that demonstrate eligibility to join the delisted low-risk PCWP 
subcategory, instead, are not subject to the section 112 MACT standard. 
Therefore, the PCWP rule follows through with the commitment to require 
all sources subject to section 112 MACT standards to conduct ``enhanced 
monitoring.''
    Comment: Two commenters addressed the use of maximum emission 
factors and the use of statistically-derived emission factors in table 
2A to appendix B to subpart DDDD. One commenter disagreed that EPA 
should use statistically-derived emission factors because, in many 
cases, there are insufficient data available to perform a statistical 
analysis. The commenter stated that where there is sufficient data, 
applying a statistical approach would not result in significantly 
different values from those already provided in table 2A to appendix B 
to subpart DDDD. The other commenter disagreed with EPA's use of 
maximum emission factors for hard-to-test process units. The commenter 
stated that some of the factors are so high that some sources will be 
forced to attempt to find ways to test the hard-to-test process units. 
The commenter suggested the EPA either multiply all emission factors by 
0.75 (or some other constant) or study the data for each factor and 
statistically select a lower factor that is still conservative and 
guards public health but enables sources to avoid costly and 
unproductive testing.
    Response: We proposed to include in appendix B to subpart DDDD the 
maximum emission factors available for each type of process unit 
because we believe use of maximum emission factors builds conservatism 
into the emissions estimates to help account for unit-to-unit 
variability and ensures protection of human health. However, in the 
preamble to the proposed amendments, we requested comment on using 
other statistical approaches. We received only one comment in favor of 
using a statistical approach, and the commenter did not provide any 
basis for assuming that emissions from untested PCWP process units are 
75 percent of the emissions from the highest-emitting process units for 
which we have data. We recognize that some of the emission factors 
presented in table 2A to appendix B to subpart DDDD are quite 
conservative, that emission testing costs can be significant, and that 
some process units cannot easily be configured for emission testing. 
However, we disagree that use of the maximum emission factors is 
unnecessarily burdensome to small plants and companies because becoming 
part of the low-risk subcategory is only one option under subpart DDDD, 
and it is an option provided to reduce the burden on PCWP facilities 
that do not pose a significant risk to human health or the environment.
2. Blenders, Sanders, and Saws
    Comment: One commenter disagreed that emissions testing is ``not 
feasible'' for several process units, including blenders, sanders, and 
saws. These sources are usually controlled by baghouses, which are 
normally required to be tested for particulate matter (PM). Because HAP 
emissions from these units can be high, the commenter recommended that 
actual test data be used rather than emission factors.
    Response: We disagree that we should require testing of blenders, 
sanders, or saws. Methanol is the predominant HAP emitted from 
blenders. Methanol can also be emitted from sanders and saws. Methanol 
is not a HAP of concern for purposes of the LRD. Our emission estimates 
indicate that the appendix B HAP emissions from blenders, sanders, and 
saws contribute to, but are not likely to drive the risk determination 
for a PCWP facility because the emissions of these same HAP from dryers 
and presses exceed those from blenders, sanders, and saws.
    Furthermore, based upon the information available to us, we 
disagree that most blenders, sanders, and saws are controlled by 
baghouses and that PM emission testing is normally required for these 
process units. We maintain that very few blenders, sanders, and saws 
are already configured for emissions testing. We also believe that we 
have struck an appropriate balance between the process units that must 
be tested and the process units for which maximum emission factor 
estimates will suffice for purposes of the LRD. As a result, we are not 
requiring emissions testing of blenders, sanders, and saws in today's 
final amendments.
    Comment: One commenter suggested converting the acetaldehyde value 
for finishing sanders from 0.0028 lb/MSF \3/8\'' to a lb/MSF surface 
area basis to be consistent with the other sander values.
    Response: As requested, we have recalculated the finishing sander 
acetaldehyde emission factor based on

[[Page 8354]]

the production rate in terms of MSF/hr, and have included the revised 
factor (0.0031 lb/MSF) in table 2A to appendix B to subpart DDDD.
3. Emission Estimates for Lumber Kilns and Small-Scale Kiln Testing
    Comment: One commenter supported small-scale lumber kiln testing. 
The commenter stated that full-scale lumber kilns are difficult to test 
because they are leaky and have highly variable exhaust rates, and most 
small-scale kilns do not have exhaust variability or fugitive emission 
issues. The commenter also noted that there is literature comparing 
results from small-scale kiln tests to the emissions from full-scale 
lumber kilns. The commenter stated that if certain conditions and 
guidelines are followed, the small-scale kiln tests can provide good 
estimates of emissions from lumber drying. The commenter suggested 
changes to the list of considerations for a small-scale kiln emissions 
testing program that was suggested by NCASI and placed in the docket 
prior to proposal of the amendments.
    Response: We recognize the difficulties with testing full-scale 
lumber kilns due to their variable exhaust flow rates, and we agree 
that measurement of small-scale kiln emissions can provide data 
representative of full-scale kiln emissions provided that certain 
conditions are met. We have reviewed the commenter's suggestions for 
the consideration list, and we have used the list (with revisions) as 
the basis for the new appendix C to subpart DDDD of 40 CFR part 63. 
Facilities that do not want to use the emission factors in table 2A to 
appendix B to subpart DDDD may conduct small-scale kiln tests taking 
into account the considerations described in appendix C to subpart 
DDDD. Small-scale kiln tests that do not address these considerations 
may be rejected during our review of the LRD. The considerations 
described in appendix C to subpart DDDD apply only for small-scale 
lumber kiln emissions testing conducted to provide data for the LRD 
described under appendix B to subpart DDDD. Permitting authorities may 
require different procedures for testing or estimating lumber kiln 
emissions for purposes other than the LRD.
    Comment: One commenter requested that EPA reevaluate the lumber 
kiln emission factors in table 2A to appendix B to subpart DDDD. 
According to the commenter, emission factors found in NCASI Technical 
Bulletin 845 are based on the most credible data, and using those 
factors generally results in much lower emissions than the values 
selected for table 2A to appendix B to subpart DDDD in the proposed 
amendments. The commenter expressed concern that using the values in 
the proposed amendments may lead to facilities being improperly 
classified as major sources of HAP.
    Response: The emission factors presented in the proposed amendments 
to appendix B to subpart DDDD are not intended to be used for major 
source determinations. Facilities that are not major sources of HAP 
emissions are not subject to subpart DDDD, and the LRD procedures are 
therefore irrelevant for those sources. The emission factors in 
appendix B to subpart DDDD are intended to be health protective and are 
intended only for use by facilities choosing not to test their lumber 
kilns for purposes of the PCWP LRD. As stated previously, facilities 
that feel the emission factors presented in table 2A to appendix B to 
subpart DDDD would over-estimate lumber kiln emissions for purposes of 
the LRD have the option of supplying facility-specific test data for 
their lumber kilns. States may require data to be obtained for major 
source determination using methods other than those described in 
appendix B to subpart DDDD.
4. Wastewater Emission Estimates
    Comment: One commenter stated that table 2A to appendix B to 
subpart DDDD should not require modeling of MDI emissions from 
wastewater and process water. The commenter stated that MDI hydrolyzes 
immediately upon contact with water, polymerizing into to an inert 
polyurea, so any wastewater from these operations cannot contain MDI.
    Response: The commenter's assertion reflects the findings presented 
by the American Chemistry Council (ACC) Diisocyanates Panel in their 
petition to remove MDI from the list of HAP under section 112(b) of the 
CAA. Based upon the findings described in the petition, we agree that 
it is appropriate to change the entry in table 2A to appendix B to 
subpart DDDD to ``NA'' for wastewater/process water operations. 
However, our action with respect to table 2A to appendix B to subpart 
DDDD does not necessarily reflect our conclusions with regard to the 
petition to delist MDI, which we are still reviewing at this time.
5. Emission Estimates for Tanks
    Comment: One commenter stated that the current wording of the 
definition of ``resin storage tank'' includes all resin additives, even 
caustic and acid. Neither caustic nor acid contain formaldehyde, 
phenol, or MDI, so emissions of the HAP of concern would not be 
expected. Additionally, the commenter stated that vessels holding 
powdered resin should not be considered resin storage tanks. The 
commenter suggested a revision of the definition of ``resin storage 
tank.'' The commenter also requested that EPA add a footnote to table 
2A to appendix B to subpart DDDD to indicate that estimating emissions 
for tanks that do not contain formaldehyde, phenol, or MDI is not 
required.
    Response: As proposed, table 2A to appendix B to subpart DDDD 
specifies default emission rates for tanks with resin containing a 
specific HAP or modeling using TANKS software. It was not our intent to 
require TANKS modeling of formaldehyde, phenol, or MDI for tanks 
holding resins without these HAP, but we realize that the language in 
the proposed table 2A to appendix B to subpart DDDD could be 
misinterpreted in this way. For the final amendments, we have revised 
the language in table 2A to appendix B to subpart DDDD to specify that 
emissions of a specific HAP need only be estimated if the tank holds a 
resin containing that HAP, regardless of whether the estimate is 
obtained using an emission factor or modeling. We also agree that it is 
not necessary to model emissions from powdered resin storage vessels, 
so we have amended the definition of ``resin storage tank'' to include 
only liquid resins and additives.
    Comment: One commenter stated that the emission factors included in 
table 2A to appendix B to subpart DDDD for resin storage tanks are 
grossly over-estimated and the alternative techniques suggested by the 
table are limited and overly simplified. In addition, the commenter 
stated that there can be a significant difference between average 
(long-term) and maximum hourly (short-term) emissions. The emission 
factors should be reduced by a factor of at least 50 for short-term 
estimates and 100 for long-term. The commenter provided sample 
calculations to support reducing the emissions factors.
    Response: We are aware that the default emission rates contained in 
proposed table 2A to appendix B to subpart DDDD for resin storage tanks 
are health protective. These emission rates represent the highest 
emission rate reported for any single tank in the MACT survey 
responses. Understanding the limitations of the default emission rates, 
we also provided modeling using EPA's TANKS software as an option for 
facilities who wish not to use the conservative default emission rates. 
To alleviate concerns about these emission rates, we have reevaluated 
the default emission rates for formaldehyde and

[[Page 8355]]

phenol. Because of the limited applicability of the emission rates 
provided in the MACT survey results, we used other conservative 
information from the MACT survey as inputs to the TANKS model to 
generate emission estimates. We arrived at default emission rates of 
0.001 pounds per hour (lb/hr) formaldehyde and 0.0002 lb/hr phenol.
    Section 7(b)(1) of appendix B to subpart DDDD requires estimation 
of annual average ambient concentrations for the chronic part of a 
site-specific risk assessment, and Sec.  (7)(b)(2) requires estimation 
of maximum short-term (hourly) emissions of formaldehyde and acrolein 
for purposes of estimating acute risk. One way to account for both 
acute and chronic exposures is to assume the worst-case for all 
emissions inputs to the risk model used to complete the acute and 
chronic portions of the analysis. Although some facilities may choose 
to use different emissions inputs in their site-specific LRD for the 
chronic and acute portions of the assessment, we disagree with the 
commenter that it is necessary for us to provide separate resin storage 
tank default emissions rates for average (long-term) and maximum hourly 
(short-term) emissions.
    Comment: One commenter stated that table 2A to appendix B to 
subpart DDDD should identify specific techniques for estimating 
emissions from open-top tanks separately from techniques used to 
estimate emissions from closed-top tanks. These types of tanks are 
often used for mixing water and other additives into the resin. The 
commenter provided an equation for estimating these emissions from the 
2002 EPA Risk Management Plan (RMP) Offsite Consequence Analysis 
Guidance (Appendix D).
    Response: Several different approaches may be used to estimate 
emissions from open-top tanks, including, for example, the 2002 EPA RMP 
Offsite Consequence Analysis Guidance (Appendix D) noted by the 
commenter. A similar approach is documented in Chapter 8, section 4.4 
of an Emission Inventory Improvement Program (EIIP) document entitled 
``Methods of Estimating Air Emissions from Paint, Ink, and Other 
Coating Manufacturing Facilities.'' In addition, WATER9 or the approach 
outlined in forms VII and VIII of appendix C to 40 CFR part 63 (and 
described further with respect to the PCWP industry in a supporting 
memorandum) could be used to estimate emissions from open-top tanks. 
Rather than dictating specific methods to be used to develop estimates 
of open-top tank emissions, we have amended table 2A to appendix B to 
subpart DDDD to distinguish between open and closed resin storage tanks 
and added a row to state that engineering estimates must be developed 
for open resin storage tanks if they hold resin with any formaldehyde, 
phenol, or MDI content.
6. Insignificant Activities
    Comment: One commenter stated that the phrase ``may emit'' included 
in the description of ancillary process units is elusive and could 
include emissions of any amount of HAP, no matter how small. The 
commenter requested that lists of insignificant and trivial activities 
be included in appendix B to subpart DDDD to streamline the process of 
preparing LRD. The commenter noted that the title V program allows 
emission units with insignificant or trivial emissions to be specified, 
but no emission estimates or permit limits are required. The commenter 
(and other commenters) provided suggested lists of insignificant and 
trivial emission units. Alternatively, the commenter suggested that the 
final amendments could explicitly allow a facility to list all the 
insignificant emission units in the PCWP source category at the 
facility and make a blanket ``engineering estimate'' evaluation that 
they are insignificant and their emissions are presumed to be zero. The 
commenter noted that if EPA disagrees with the facility's designation 
of an emission unit as an insignificant emission unit during its review 
of low-risk determination, then it can notify the facility that 
additional justification of its engineering estimate is needed for that 
emissions unit.
    Response: The amended rule does not include lists of insignificant 
or trivial activities for several reasons which are documented in the 
BID for the final amendments. Instead, we have adopted the commenter's 
alternative suggestion. Each facility completing a LRD may include a 
site-specific list of insignificant activities for which the facility 
may make an engineering estimate of presumably zero appendix B 
emissions. The facility must provide rationale to document placement of 
each process unit or activity on the list (e.g., the unit does not 
process HAP-containing materials; no heat is applied; there is no 
mechanism for appendix B HAP formation, etc.). We will evaluate each 
facility's list of insignificant activities when reviewing the LRD. Any 
data that support the placement of a certain activity on the 
insignificant activities list should be included with the facility's 
LRD. Only process units and activities within the PCWP affected source 
should be included in this list.
    Comment: One commenter noted that EPA did not include a definition 
of ``ancillary processes'' in the rule and suggested a possible 
definition.
    Response: We agree that a definition of ``ancillary processes'' is 
needed since the term is used in table 2A of appendix B to subpart 
DDDD, and we have defined the term in section 15 of appendix B to 
subpart DDDD based on the definition suggested by the commenter (with 
necessary edits).
7. Other Specific Comments on Table 2A to Appendix B to Subpart DDDD
    Comment: One commenter requested that a footnote be added to the 
formaldehyde emission factor for particleboard and medium density 
fiberboard (MDF) blending and forming operations in table 2A to 
appendix B to subpart DDDD. The footnote should state that the factor 
applies only to facilities using formaldehyde-based resins. 
Formaldehyde emissions from facilities that use 100% non-formaldehyde 
resins or adhesives (such as MDI) should be designated ``NA.''
    Response: We agree with the commenter that it is appropriate to 
clarify that estimation of formaldehyde emissions from particleboard 
and MDF blending and forming operations is only necessary for those 
facilities that use resin containing formaldehyde. We have amended the 
final rule to include such a footnote.
    Comment: One commenter supported excluding metals testing for 
process units firing only natural gas or propane and stated that 
footnote b of table 2A to appendix B to subpart DDDD should be revised 
to clarify that no emissions estimates are required for direct-fired 
process units firing natural gas or propane.
    Response: We agree with the commenter's suggested change to the 
footnote b of table 2A to appendix B to subpart DDDD and we have 
amended the footnote as requested.

G. Emission Testing Requirements in Appendix B to 40 CFR Part 63 
Subpart DDDD

1. Testing of Multiple Identical Dryers
    Comment: One commenter supported the proposed amendment giving 
facilities the ability to use emissions test data from one unit for 
modeling of similar process units. The commenter stated that the 
proposed amendment will help industry better manage emissions testing 
costs and testing resources while ensuring data quality. Another 
commenter stated that EPA should consider age as a factor when 
determining whether units are similar.

[[Page 8356]]

As proposed, the amendment would inappropriately allow newer and 
cleaner-operating equipment to be tested in place of older, more run 
down equipment without any loss of emissions estimating accuracy.
    Response: As a result of the second comment, we reviewed available 
data to see if any correlations with age of the process units are 
apparent. We concluded that we do not have the emissions test data 
spanning decades necessary to confirm or refute the commenter's 
assertion that age of the process unit is a crucial consideration. We 
generally agree that process units that are considerably older could be 
expected to have greater emissions than newer process units of the same 
design, particularly if the older process units have not been well 
maintained. Therefore, we have included age of the process unit as a 
consideration when applying test data from one unit to another similar 
unit at a plant site to be conservative. However, we wish to clarify 
that we consider distinctions in the age of the process unit, for 
purposes of the PCWP LRD, to be many years (e.g., 5 to 10 years) since 
our data do not show increased emissions as process units age over a 
few years.
    Comment: One commenter suggested that EPA allow facilities to test 
one of multiple stacks or vents when the gases in those vents have been 
collected from the same process unit, originate from the same duct or 
vent, and are not expected to differ in gaseous pollutant 
concentration. The commenter clarified that this procedure should not 
be allowed unless the emissions have been collected and then 
subsequently divided (e.g., the procedure would be inappropriate for 
multiple vents above a wood products press).
    Response: We agree with the commenter that applying results from 
one stack test to the emissions from multiple stacks is acceptable for 
purposes of the LRD when the gases in those stacks or vents have been 
collected into a single duct and subsequently divided and are not 
expected to differ in gaseous pollutant concentration. We also agree 
with the commenter that testing one of multiple process unit openings 
or vents, such as the vents above a wood products press, should not be 
allowed because the concentration from such vents could differ. We have 
added a paragraph to section 5 of appendix B to subpart DDDD to 
incorporate this suggestion.

2. Use of Previous Emission Tests

    Comment: One commenter supported the proposed amendment to allow 
facilities to use previous emissions test data for the purposes of LRD. 
The commenter stated that the proposed amendment will help industry 
better manage emissions testing costs and testing resources while 
ensuring data quality. However, the commenter stated that rather than 
limiting the use of previously determined emission factors to those 
units that operate at the same conditions as during the emission test, 
EPA should require the subject units to be operated in a manner that 
would result in lower emissions. Another commenter stated that EPA 
should consider age as a factor when determining whether units are 
similar. As proposed, the amendment would inappropriately allow newer 
and cleaner-operating equipment to be tested in place of older, more 
run down equipment without any loss of emissions estimating accuracy.
    Response: We agree with the first commenter that it is not often 
possible for a process unit to be operated under the exact same 
conditions as during a previous performance test. It was not our 
intention for this provision to be interpreted quite so literally. We 
have revised section 5(i)(3) in appendix B to subpart DDDD to state 
that the subject process units must be operated in a manner that would 
be expected to result in the same or lower emissions than observed 
during the previous emissions test and that the process units must not 
have been modified such that emissions would be expected to exceed the 
results from the previous emissions test.
    Regarding the second comment, we discussed the effects of process 
unit age in a previous response. We are limiting previous data 
submitted for purposes of the LRD to emissions test data gathered in 
1997 or later. We picked 1997 as the cutoff date because we recognize 
that a great deal of HAP emissions data was gathered for PCWP process 
units during that year, and we do not believe that this data is 
obsolete at this time provided the other conditions of section 5(i) of 
appendix B to subpart DDDD are met.
3. Fuel Analysis To Determine HAP Metals Emissions
    Comment: Two commenters supported EPA's suggestion of using fuel 
analyses to estimate HAP metal emissions for direct-fired process 
units. One of these commenters stated that EPA should allow PCWP 
facilities to use procedures similar to those in subpart DDDDD, the 
Industrial, Commercial, and Institutional Boilers and Process Heaters 
NESHAP (Boilers/Process Heaters rule). This option would lower testing 
cost yet provide a maximally conservative value that would be 
protective of public health.
    Response: We have decided to adopt a fuel analysis procedure 
similar to the procedure described in the Boilers/Process Heaters rule. 
Section 5 of appendix B to subpart DDDD includes a new paragraph 
referring to the relevant sections of subpart DDDDD. Plywood and 
composite wood products facilities may conduct a fuel analysis in lieu 
of emissions testing for HAP metals for purposes of the LRD. The 
relevant sections of the Boilers/Process Heaters rule include Sec.  
63.7521(a) and (c) through (e); Sec.  63.7530(d)(1), (2), and (4); and 
line 2 of table 6 to subpart DDDDD. For purposes of conducting a fuel 
analysis for a PCWP LRD, ``total selected metals'' means the 
combination of the metal compounds included in table 1 to appendix B to 
subpart DDDD.
4. Formaldehyde and Phenol Test Methods
    Comment: One commenter stated that NCASI Method CI/WP-98.01 should 
be allowed for formaldehyde and phenol measurement in table 2B to 
appendix B to subpart DDDD. The method is allowed in other parts of the 
rule for measurement of formaldehyde, phenol, and methanol, but it was 
not included in appendix B to subpart DDDD. The commenter stated that 
using NCASI Method CI/WP-98.01 instead of NCASI Method IM/CAN/WP-99.02 
would reduce sampling cost and complexity without sacrificing sampling 
precision and accuracy.
    Response: We agree that NCASI Method CI/WP-98.01, ``Chilled 
Impinger Method for Use at Wood Products Mills to Measure Formaldehyde, 
Methanol, and Phenol,'' is appropriate for measurement of formaldehyde 
and phenol. We have added NCASI Method CI/WP-98.01 to table 2B to 
appendix B to subpart DDDD for formaldehyde and phenol testing only.
    To be consistent with the test methods allowed in subpart DDDD, we 
have also edited table 2B to appendix B to subpart DDDD to allow use of 
Method 0011 for formaldehyde and acetaldehyde, and to allow use of 
Method 316 (40 CFR part 63, appendix A) for formaldehyde.
    In addition, a revised version of NCASI Method IM/CAN/WP 99.02 has 
been placed in Chapter III of the NCASI Methods Manual and the PCWP 
docket. The NCASI made minor revisions to the IM/CAN/WP 99.02 method to 
(1) clarify sections easily misunderstood or that did not provide 
sufficient instruction and (2) to add some flexibility to the quality 
assurance procedures and

[[Page 8357]]

criteria. We reviewed and agreed with these minor changes to the 
method.
5. Determining MDI Emissions
    Comment: One commenter suggested that EPA also consider the use of 
EPA proposed Method 207, ``A Method for Measuring Isocyanates in 
Stationary Source Emissions,'' for measurement of MDI emissions. Method 
207 is expected to provide lower detection limits than EPA CTM-031 and 
Method 320, which are already allowed to be used.
    Response: We proposed Method 207 in the Federal Register on 
December 8, 1997 (62 FR 64532). A copy of the proposed method may be 
downloaded from http://www.epa.gov/ttn/emc/proposed.html. We intend to 

make minor revisions to the method and promulgate it in appendix M to 
40 CFR part 51 within the next few months. We will accept data measured 
using the proposed Method 207 before the promulgated version of the 
method becomes available. Once promulgated, the final method 207 will 
appear in the Federal Register, appendix M to 40 CFR part 51, and on 
http://www.epa.gov/ttn/emc/promgate.html.


H. Compliance Date for Existing Sources

    Comment: In response to our request for comment on the issue, 
several commenters requested an extension of the MACT compliance 
deadline (October 1, 2007, for existing sources). One commenter stated 
that EPA should consider a compliance deadline extension for all PCWP 
sources because of uncertainties associated with the promulgated 
amendments, or ``supplemental rule.'' The commenter stated that EPA 
could give sources 3 years (the maximum amount of time for compliance 
allowed by section 112(i)(3)(A) of the CAA) from the effective date of 
the supplemental rule. The commenter requested a new compliance date of 
August 1, 2008 (based on an extended LRD submittal deadline of March 1, 
2008), and noted that this date is less than three years from the 
anticipated promulgation date of the supplemental rule. A separate 
commenter suggested extending the PCWP MACT compliance deadline to 
March 1, 2009 (based on a suggested LRD submittal deadline of March 1, 
2008). Another commenter suggested extending the PCWP MACT compliance 
deadline to October 1, 2008 (based on a suggested LRD submittal 
deadline of April 1, 2007). The above commenters also suggested that 
EPA extend the compliance dates for sources that submit LRD that are 
not approved by EPA.
    One commenter disagreed that facilities that do not submit a LRD 
should be granted any additional time to comply with MACT. The 
commenter also stated that if an existing facility's LRD is not 
approved, the facility should be given no more than one year from the 
current compliance date to comply with all requirements of the rule. 
Another commenter asserted that section 112(i)(3)(A) denies EPA 
authority to extend the rule's compliance date beyond October 1, 2007 
for sources whose LRD are disapproved or for all PCWP sources.
    Response: We are promulgating a MACT compliance date of October 1, 
2008 in today's final action. We are providing this new compliance date 
for all PCWP sources (as opposed to only those sources that submit 
LRD). We are making this change to the MACT compliance date because 
today's final action results in revisions to several definitions in 
subpart DDDD and to the testing requirements in appendix B to subpart 
DDDD that are substantial and warrant revision of the MACT compliance 
date.
    Our proposal specifically asked for comments on whether to set a 
new compliance deadline for all sources covered by the PCWP NESHAP. As 
mentioned by the commenters, section 112(i)(3)(A) of the CAA specifies 
that NESHAP for existing sources can have compliance deadlines of no 
more than 3 years following the effective date of their promulgation. 
The question then becomes which promulgation date to apply--July 29, 
2004, which is the date the PCWP NESHAP was first promulgated, or 
today's date, on which we are promulgating numerous revisions to the 
rule. We interpret section 112 of the CAA as providing us with the 
authority to re-set the compliance deadline for NESHAP, as appropriate, 
in situations where promulgated amendments to the regulation are 
significant and substantial enough to warrant revisiting the question 
of how much time is needed for subject sources to comply with the 
requirements of the rule, as amended. This includes situations where a 
NESHAP is significantly revised to include additional control 
requirements in response to either a court's remand of the original 
rulemaking or a petition for reconsideration of the rule, or is so 
revised on the agency's own initiative.
    We agree with the commenters that noted that section 307(b)(1) of 
the CAA specifically provides that the filing of a petition for 
reconsideration of a rule does not postpone the effectiveness of the 
rule. We do not consider the mere fact that a rule has become the 
subject of a petition for judicial review or a petition for 
administrative reconsideration to necessarily justify a re-setting of 
the compliance deadline. As we stated in the final reconsideration 
notices for the Brick and Boiler MACT rules (70 FR 69661, November 17, 
2005 and 70 FR 76928, December 28, 2005, respectively), the 
uncertainties raised by reconsideration do not in general necessarily 
justify an extension of the compliance date. Instead, the facts of each 
rule's potential revision and the degree of the significance of the 
rule's amendments should be considered on a case-by-case basis. Where 
EPA has amended a MACT standard in a significant way, we have found it 
appropriate to set a new compliance date for the rule that takes into 
account new requirements not contained in the original rule. The 
relatively greater degree of changes we made to the overall PCWP rule, 
which substantially affect how it will be implemented for the majority 
of sources, as compared to changes we made to the Boiler MACT (we made 
no changes to the Brick MACT due to reconsideration), for example, 
justify a different outcome for the PCWP rule.
    Thus, changes in expectations about the numbers and types of 
sources that will need to obtain, install and certify pollution control 
equipment to comply with the rule's requirements overall are 
compelling. Since the 2004 rule's promulgation, we found that many, 
even most, facilities expect to install controls or make other physical 
changes to the mill to meet the low-risk criteria. While we recognized 
in 2004 that some sources would have to make these changes to become 
low risk, we did not predict accurately the number of sources that 
would do so. Rather, we expected that sources needing to obtain, 
install and certify controls would be primarily those remaining in the 
MACT category, such that MACT-subject sources would face comparably 
less competition from would-be low-risk sources in seeking available 
vendors for those controls under the original compliance deadline of 
October 1, 2007. We now have a better understanding that more sources 
than we first anticipated in 2004, both MACT and low-risk sources, will 
need to install controls and will be competing for the services of a 
limited number of control device vendors.
    In addition to the difficulties sources may encounter in installing 
controls and testing emissions, before today's final action, some 
sources faced uncertainty about whether they were part of the PCWP 
source category as defined in the

[[Page 8358]]

2004 promulgated NESHAP. We received several requests from sources and 
permitting authorities as to the applicability for certain types of 
processes such as molded particleboard and curved plywood components. 
We determined that many of these sources were part of the source 
category, but few had associated control requirements. However, some, 
we do not how many, may be required to control emissions (e.g., for a 
dryer). These are sources, such as furniture manufacturers, who 
believed they were not subject to the MACT standards in 2004. Since 
that time, through definitional changes in today's final action and 
assistance with applicability determinations, we have provided the 
necessary clarifications so that these sources may begin the process of 
determining their regulatory obligations, which could include 
installation of emissions controls.
    As stated above, we do not generally regard the perceived 
``uncertainty'' related to the reconsideration and amendment process as 
constituting a sufficient reason in and of itself for revising the 
overall compliance date. We note that prior to our issuance of today's 
final action, sources were able to begin emissions testing for purposes 
of the LRD with little certainty of what the final potentially-revised 
emissions testing requirements would be. Furthermore, the entire 
content of appendix B to subpart DDDD was under reconsideration. While 
this did not affect the effectiveness or applicability of the 
originally promulgated requirements pending our rulemaking process, we 
have learned that the reconsideration and amendment process did affect 
source decisions about whether to comply with the MACT standards or to 
apply to join the low-risk subcategory, which, ultimately, caused some 
sources to delay decisions about MACT compliance.
    The emissions testing that facilities must complete for purposes of 
the LRD involves careful planning (e.g., deciding what process units to 
test and for which HAP, selection of test contractors, selection of 
test methods, test plan development, etc.) and the expense of such 
testing depends greatly on the number of process units and HAP that 
must be tested. Many facilities will likely plan and conduct emissions 
tests that serve a dual purpose: (1) To determine emissions of the 
appendix B HAP for purposes of the LRD, and (2) to determine 
uncontrolled emissions levels to identify potential MACT compliance 
options (e.g., to identify emissions averaging opportunities or see if 
emissions fall below the production-based compliance option) should the 
facility decide not to pursue the low-risk option. Facilities may view 
it as more economical to conduct testing of multiple process units and 
HAP combinations at one time than to repeatedly test individual process 
units for a few HAP (e.g., because test methods covering multiple HAP 
can be used, and there is less travel expense for test contractors if 
multiple tests are completed in one trip). Once onsite stack sampling 
is completed, laboratory analysis of the samples must be conducted and 
test reports prepared. The emissions testing that PCWP facilities must 
conduct, from the planning stage to receiving the final report, can 
easily take 9 months to 1 year. More time may be required if the 
testing company or laboratory does not correctly perform the tests or 
analysis the first time due to the difficulty of some of the test 
methods (e.g., relatively new NCASI test methods developed specifically 
for the PCWP industry). While adding these methods add flexibility for 
sources, sources did not know until today whether the final rule would 
incorporate them. We also recognize that the number of testing 
contractors with the equipment and familiarity needed to run the NCASI 
methods is limited, and that there will be much competition for the 
qualified testing contractors. Today's final amendments allow use of 
more test methods applicable to the multiple HAP of concern than did 
the 2004 final NESHAP (e.g., we are incorporating by reference the new 
NCASI method ISS/FP-A105.01), and before today's final amendments 
facilities were uncertain which methods would be acceptable. In 
addition, today's final amendments allow other emissions determination 
approaches such as small-scale kiln testing, fuel analyses to predict 
HAP metals emissions, and modeling of tank or wastewater emissions. For 
these reasons, many sources have delayed their emissions testing 
activities until after today's final amendments are promulgated. 
Emissions testing is only one step in completion of the LRD (i.e., it 
will take several months to a year or more for PCWP facilities to 
complete their LRD incorporating all of the emissions data and to 
complete changes to their facility to ensure they can meet the low-risk 
criteria on an ongoing basis). Although the changes to the overall rule 
are significant and the CAA allows us to set a new compliance date 3 
years from the promulgation of today's final rule, we concluded only an 
additional 12 months beyond the original compliance date is necessary.
    Comment: Two commenters stated that there is no reason why a source 
should not be able to move from the MACT to the low-risk subcategory if 
changes occur such that the facility qualifies as low-risk (e.g., 
equipment installation that reduces emissions or any future changes to 
the health benchmarks for acrolein and acetaldehyde), even if the 
facility qualifies after the MACT compliance deadline. The commenter 
stated that although these facilities would have already incurred the 
expense associated with MACT control installation, it may still be 
worthwhile to be classified as low-risk because of the reduced 
recordkeeping and reporting burdens.
    Response: We agree that sources should be able to join the low-risk 
subcategory before or after the MACT compliance date. Allowing sources 
to become part of the low-risk subcategory after the MACT compliance 
date gives facilities more time to complete any physical changes 
necessary to operate as low risk, more time to complete their LRD, and 
more time to complete their permit applications. Existing sources 
needing extra time must comply with the MACT requirements in subpart 
DDDD as of October 1, 2008 and until they are part of the low-risk 
subcategory. Since the CAA does not prohibit us from adding sources to 
delisted subcategories after the MACT compliance date and existing 
sources must comply with MACT if not in the low-risk subcategory by the 
MACT compliance date, allowing sources additional time to complete 
their LRD is reasonable and should be allowed. Therefore, we have 
revised Sec.  10 of appendix B to subpart DDDD accordingly.

I. Low-Risk Demonstration Submittal Dates for Existing Sources

    Comment: Four commenters supported an extension of the LRD 
submittal deadline established in the 2004 final rule. One commenter 
supported the proposed revised date of April 1, 2007. Three additional 
commenters suggested extending the LRD submittal date beyond the 
proposed date of April 1, 2007, and requested that EPA adopt extensions 
of the LRD and MACT compliance deadlines to March 1, 2008, and August 
1, 2008, respectively. One commenter stated that most facilities did 
not begin emissions testing upon promulgation of the PCWP rule because 
they were aware that clarifying amendments would be forthcoming. The 
commenters arrived at the March 1, 2008, low-risk submittal date by 
estimating the amount of time that would be needed to complete each

[[Page 8359]]

of eight steps that influence the timing of completing a LRD, 
including: Planning and performing emissions tests, completing a risk 
assessment, securing the capital needed to make any changes to the 
source, installing control devices or completing other physical 
changes, selecting and hiring contractors and control device vendors, 
coordinating the LRD activities of multiple facilities, receiving EPA 
approval of the LRD, and preparing the application for a title V permit 
modification.
    Two commenters disagreed that EPA should extend the LRD submittal 
date. One commenter believes that extending the LRD submittal deadline 
would simply encourage sources to spend time and resources attempting 
to obtain unlawful exemptions instead of dedicating themselves to 
meeting the rule's cleanup standards by the 2007 compliance date. 
Another commenter stated that some facilities have already completed 
their LRD and are simply waiting for the amendments to be promulgated 
before submitting them.
    Response: As explained above, we have revised section 10 of 
appendix B to subpart DDDD so that sources may become part of the low-
risk subcategory any time. Therefore, there is no deadline for existing 
sources to become part of the low-risk subcategory in today's action. 
Existing sources that are not part of the low-risk subcategory on 
October 1, 2008 must be in compliance with the MACT standards in 
subpart DDDD.
    We realize that some existing sources will want to be part of the 
low-risk subcategory by the MACT compliance date to avoid MACT 
compliance. For those sources, EPA will review complete and well-
documented LRD received by February 1, 2008 and make every attempt to 
notify sources of our determination of their eligibility to become part 
of the low-risk subcategory no later than August 29, 2008. (A complete 
and well-documented LRD includes emissions tests performed on the 
facility as it will be operated and includes the documentation required 
in appendix B to subpart DDDD.) We believe this approach balances the 
time we need to review and approve (or disapprove) LRD with the time 
sources need to complete activities associated with the LRD.
    We do not know how many facilities will submit LRD on or by 
February 1, 2008, but it could be well over a hundred. We plan to 
review LRD in the order we receive them and encourage sources to submit 
their LRD as early as possible. (We will review preliminary LRD based 
on modeling and emissions factors before February 1, 2008 and as our 
resources permit. Although these LRD will not be approvable, sources 
that want a review of their LRD at this preliminary stage should engage 
us as the earliest possible date.) We note that we may not be able to 
interact with sources as we might have otherwise (e.g., ask for 
clarification, recommend minor changes) as the MACT compliance date 
approaches because of time and resource constraints. If we have many 
LRD to review, we will likely return incomplete demonstrations without 
further review. We will likely notify these sources that we could not 
approve the LRD at that time. Sources whose LRD are deficient may re-
submit revised demonstrations, but we will likely not review re-
submittals until we have completed our review of all the other timely 
and complete LRD we have first received.
    As to the decision individual sources make regarding whether to 
spend resources on demonstrating they are low risk, the decision is 
theirs to make. Similarly, a source must determine for itself when to 
submit its LRD. We encourage sources to submit their LRD before 
February 2008 so that we have time to work with sources to resolve 
deficiencies in their LRD and so that sources have time to resubmit 
their LRD (if necessary) prior to February 1, 2008.
    Comment: One commenter supported EPA's proposal to allow a 
preliminary LRD that is based on proposed physical changes to the plant 
that have not yet been completed or verified by stack testing. The 
commenter noted that this approach addresses some timing concerns and 
also helps to ensure that sources do not undertake expensive facility 
changes only to find that EPA does not approve their LRD. The commenter 
noted that EPA should give sources until the proposed April 1, 2007, 
deadline (assuming this deadline is not extended further) to submit LRD 
that are based on proposed physical changes at the plant, and the 
facility should be required to complete the physical changes by October 
1, 2007.
    The commenter stated that, for sources making physical changes to 
comply with the low-risk criteria, confirmatory emissions testing 
should be required by the date on which performance testing for MACT 
compliance is due in the 2004 final rule (i.e., 180 days after the 
compliance deadline). This proposed timing makes sense because physical 
changes to meet the low-risk criteria and physical changes to meet one 
of the other compliance options follow similar engineering and capital 
planning timelines. The commenter noted that sources not making 
physical changes to their facilities should be allowed to conduct 
emissions tests after the low-risk submittal date but before the 
compliance date.
    The commenter also supported EPA's proposal to allow sources to 
submit a preliminary LRD that relies on emissions factors. However, it 
is critical that EPA provide the source with confirmation that the 
source has used an acceptable methodology and that, if emission testing 
provides the results anticipated by the source, the source will meet 
the low-risk criteria and its demonstration will receive final 
approval. The commenter noted that allowing preliminary LRD will enable 
EPA to spread the demonstration reviews over a longer period of time 
because sources will submit their preliminary demonstrations earlier. 
In addition, if the preliminary demonstration is not approved, sources 
have more time to amend their demonstration or prepare for alternative 
compliance options.
    The commenter suggested that EPA allow facilities to propose in 
their title V applications which process parameters will be limited and 
state that the emission limits will be set as a result of the most 
recent emission test. As a result of this change, States would not be 
able to issue the title V permit revision prior to the facility 
receiving approval of the LRD.
    Another commenter argued that EPA would not have the time to 
thoroughly review both a pre-clearance application and a subsequent, 
emissions test-based verification that emissions do not exceed the 
emission factor calculations presented in the LRD. The commenter 
contended that EPA will likely focus on sources' pre-clearance 
submissions (in which sources have every reason to be overly 
optimistic) and pay only cursory attention to the subsequent compliance 
demonstrations.
    Response: Existing sources may submit preliminary LRD at any time, 
including those without the required emissions tests and without 
completing physical changes to the facility. However, existing sources 
must complete the required emissions tests and physical changes to the 
facility, submit the complete LRD to EPA, receive approval from EPA (if 
the LRD is approvable), and apply for their title V permit revision 
before becoming part of the low-risk subcategory. We will consider 
preliminary LRD that do not contain the required emissions test data to 
be incomplete and we will not approve any LRD submitted by existing 
sources that do not contain this required information.

[[Page 8360]]

    We recognize that it may be necessary to complete physical changes 
to emission sources before the required emissions testing can be 
conducted. Existing sources may now submit their LRD any time (as 
opposed to July 31, 2006, as originally promulgated). While giving 
sources more time to complete their LRD, we have minimized the amount 
of time we will have to review the numerous LRD that we anticipate will 
be submitted by February 1, 2008. Therefore, we will review 
preliminary, incomplete LRD only before February 1, 2008. After that 
date we will focus our efforts on reviewing complete LRD in fairness to 
those facilities that are low-risk without having to make physical 
changes to their emission sources and those facilities that completed 
their physical changes and emissions testing before February 1, 2008. 
As time allows, we will review and provide feedback to facilities 
submitting preliminary LRD several months prior to February 1, 2008. In 
addition, we will accept and attempt to complete our review of final 
LRD (that contain the required emissions test data) submitted after 
February 1, 2008 that are follow-up to preliminary LRD we have 
previously reviewed. Subsequent LRD submittals are likely to use the 
same risk assessment procedures and should not need as much time to 
review.
    Existing sources will have about 2 years to complete their LRD and 
the necessary physical changes to their facilities between the time 
today's final action is available and the February 1, 2008 LRD 
submittal date. These 2 years, coupled with the availability of the 
low-risk criteria and risk methodology published in the 2004 final 
rule, should provide enough time for existing sources to become part of 
the low-risk subcategory by October 1, 2008 if they wish and have 
planned accordingly. Sources may also choose to submit their LRD later, 
and comply with the MACT requirements in subpart DDDD on the compliance 
date and until they become part of the low-risk subcategory.

J. Compliance Date for Affected Sources Previously Qualifying for the 
Low-Risk Subcategory

    Comment: Two commenters disagreed with the 3-year MACT compliance 
extension for existing sources that are temporarily low-risk but begin 
to operate outside of the low-risk subcategory due to a population 
shift or change in dose-response values. One commenter stated that the 
CAA requires existing sources to comply no later than 3 years after the 
effective date and that EPA offers no legal justification or rationale 
for the extra 3 years provided to PCWP sources that are no longer low-
risk.
    Other commenters supported EPA's decision to allow sources in the 
low-risk subcategory to have 3 years to comply with the MACT limits 
when they are no longer part of the subcategory due to factors outside 
their control. The commenters stated that this is consistent with the 
normal 3-year period for sources to comply with a MACT standard after 
the effective date. The commenters stated that a 3-year compliance 
window is necessary to ensure the necessary steps are completed to 
transition between the low-risk subcategory and MACT compliance. 
Another commenter stated that this approach is exactly consistent with 
the existing regulatory provisions for area sources which become major 
sources (and thus are subject to MACT) and have 3 years to comply with 
MACT.
    The commenter believes EPA has closed a potential loophole, rather 
than creating one as petitioners claim. That is, CAA section 112(c)(9) 
includes no provision for sources becoming ``re-subject'' to MACT if 
they no longer are low-risk. Rather, CAA section 112(c)(9) assumes that 
once a category is delisted, all sources in that category are 
permanently exempt from MACT. The commenter believes that, under the 
statute, if the subcategory no longer qualifies as low-risk, EPA must 
affirmatively relist the subcategory (and no deadline is provided by 
which EPA must do so). Relisting the category, in turn, would require 
EPA to promulgate MACT standards within 2 years, with compliance 
another 3 years later (or, a 5-year process in total from the date EPA 
decided to relist the category). The commenter believes that EPA has 
adopted a more protective approach and required compliance within 3 
years.
    Response: We agree with the commenter who analogized sources in 
this situation, where they lose low-risk eligibility due to changing 
factors that are outside their control, to the way we generally address 
area sources that undergo changes that subject them to MACT for the 
first time. In both cases, a source that was previously not part of the 
MACT-regulated category has become subject to MACT, and it is necessary 
for us to anticipate a feasible period for bringing the source into 
MACT compliance. Unlike the situation of a low-risk source that 
undergoes a change that it should know may have an effect on its 
ability to maintain low-risk status (for which we are retaining the 
2004 final rule requirement that the source comply with MACT 
immediately upon the change), a source whose low-risk status is 
affected by changes outside of its control will need some time to 
comply with MACT, especially where the installation of controls is 
necessary. We appreciate the commenter's agreement that our approach 
for ensuring that sources that lose their low-risk status timely comply 
with PCWP MACT requirements is reasonable. However, we disagree with 
the commenter's suggestion that the alternative to our approach is to 
have to relist under CAA section 112(c)(1) either the ex-low-risk 
source or the entire low-risk subcategory before subjecting that source 
to MACT. This is because there are only two possible subcategories a 
PCWP source can belong to: Either the MACT-regulated category, or the 
delisted low-risk subcategory. If a low-risk source loses its 
eligibility for membership in the low-risk subcategory, it necessarily 
follows that it then rejoins the MACT-regulated category, since there 
is no other PCWP category or subcategory for the source to join. Our 
approach is intended to make this necessary transition occur 
efficiently, effectively and fairly.
    Since it is possible that the types of changes in this situation, 
such as a change to a more stringent RfC, may have an impact on a large 
number of previously low-risk sources, it is fair and reasonable to 
establish a common compliance deadline for all such similarly affected 
sources. In adopting the 2004 final rule, based on the information 
before us, we determined that sources covered by the PCWP NESHAP would 
need the full statutory 3 years to comply due to the expected schedule 
for ordering and installing controls from the available vendors. Low-
risk sources that, due to changes outside their control, suddenly find 
themselves in the PCWP MACT category, will essentially be placed in the 
same position as were PCWP MACT sources upon promulgation of the rule--
that is, an event has occurred that has made them subject to the rule 
even though they took no action on their part to trigger the event. 
Likewise, those sources may very well then find themselves at the stage 
of the process that PCWP MACT sources faced in 2004, and have to begin 
finding a control vendor who can install controls on time. Based on the 
information we have today, we continue to believe that the full 3 years 
is needed for sources in this situation who become subject to MACT, and 
we see no reason to treat the two situations differently as the same 
process and obstacles will be faced by these sources. On the other 
hand, for sources that initiate their own changes that would affect 
their low-risk status,

[[Page 8361]]

we continue to believe that MACT planning must be built into those 
sources' considerations, and therefore maintain the requirement that 
they comply with MACT immediately upon undergoing changes.

K. Low-Risk Demonstration Submittal Dates for New Sources

    Comment: Two commenters suggested that new sources submit a 
preliminary LRD before startup. One commenter requested that EPA 
clarify the procedures for new sources to be included in the low-risk 
category by allowing the demonstration to be submitted during 
construction using conservative factors, as provided for in Sec.  5(h) 
of appendix B to subpart DDDD, with EPA approval prior to startup. 
Subsequent testing could be conducted within 180 days to demonstrate 
that actual emissions are below the rates used in the demonstration. 
The other commenter stated that new PCWP facilities that plan to join 
the low-risk subcategory should be required to submit a preliminary 
eligibility demonstration with their pre-construction permit 
application. That way, State and local agencies will know at the time 
the construction permit application is submitted that the facility 
plans to submit a LRD and may be exempted from the MACT requirements at 
a later date. The commenter noted that subpart DDDDD (the Boilers/
Process Heaters rule) requires a preliminary eligibility demonstration 
using emissions estimates, and it also requires the facility to verify 
the data with source testing within 180 days of startup. The commenter 
also noted that since there are no provisions in the CAA for extending 
the compliance date for new sources, new sources that are denied the 
risk-based exemption must comply at startup and State and local 
agencies must include all the requirements of the PCWP MACT in their 
permits.
    In addition, one commenter stated that it is not possible for new 
or reconstructed sources to conduct their emissions testing upon 
initial startup because the rule requires the facility to be run at 
maximum capacity during testing and new facilities take at least 3 
months to reach maximum capacity. Therefore, submitting a LRD 180 days 
after startup is not reasonable for new or reconstructed sources. The 
commenter requested that new and reconstructed sources be required to 
conduct stack testing within 180 days of initial startup and to submit 
their LRD within 240 days of initial startup.
    Response: Unlike existing sources, new sources cannot conduct the 
required emissions testing prior to startup. Therefore, we agree that 
requiring new sources to submit a pre-startup LRD would be useful. It 
allows new sources to determine whether or not they are likely to be 
low-risk facilities and helps permitting authorities by notifying them 
which sources plan to demonstrate eligibility for the low-risk 
subcategory. Therefore, today's final action requires new sources to 
submit a pre-startup LRD at least 9 months prior to startup. The pre-
startup LRD must be based on the information (e.g., equipment types, 
estimated emission rates, etc.) that will likely be used to obtain the 
sources' title V permit and must incorporate the maximum emissions that 
will likely be allowed under the title V permit. New sources will also 
be required to submit a verification LRD, based on emissions testing, 
where required.
    Today's action provides three options for new sources who want to 
become part of the low-risk subcategory. When new sources submit their 
pre-startup LRD, they must indicate whether they intend to join the 
low-risk subcategory based on their pre-startup LRD (option 1) or based 
on their verification LRD (option 2). The third option is for new 
sources to comply with the requirements of MACT in subpart DDDD at 
startup and join the low-risk subcategory after startup using the 
procedures for sources already in compliance with MACT provided in the 
amended section 10(b) of appendix B to subpart DDDD.
    The first option allows new sources to join the low-risk 
subcategory based on their pre-start-up LRD (i.e., upon startup). The 
EPA will review and approve (if approvable) the source's pre-startup 
LRD prior to startup. The source must operate, and certify they are 
operating, consistently with their pre-startup LRD. After startup, the 
source must submit a verification LRD, based on the emissions 
determination requirements in table 2A to appendix B to subpart DDDD. 
The EPA will review the verification LRD. If the verification LRD does 
not support the pre-startup LRD, the source must comply with MACT for 
new sources immediately. This is not to say that the verification LRD 
must match the pre-startup LRD exactly. In fact, we would expect that 
the pre-startup LRD would be more conservative than the verification 
LRD. So while the two LRD may differ, the verification LRD must 
demonstrate that the facility can operate consistently as low risk and 
that the facility operated as low risk based on the pre-startup LRD.
    The second option is for new sources join the low-risk subcategory 
based on their verification LRD (i.e., to operate consistently with 
their pre-startup LRD at startup and join the low-risk subcategory once 
EPA reviews and approves (if approvable) their verification LRD). The 
new source would submit a pre-startup LRD and EPA would review it prior 
to startup of the facility. The facility would then operate and certify 
operating consistently with their pre-startup LRD. The source becomes 
part of the low-risk subcategory when EPA approves (if approvable) 
their verification LRD. As required for sources choosing option 1, if 
the verification LRD does not support the pre-startup LRD, the source 
must comply with MACT for new sources immediately. Also, as for sources 
using option 1, we do not expect the pre-startup LRD to match the 
verification LRD exactly, but do require that the source operate as low 
risk from startup or comply with MACT.
    New sources must submit an application for a significant title V 
permit modification to incorporate the low-risk parameters from the 
verification LRD into their title V permit within a year of their 
startup date.
    New sources choosing either option 1 or option 2 face enforcement 
liability if the source's verification LRD source does not confirm 
their low-risk status. If the verification LRD does not demonstrate 
that the source is low risk, the source is out of compliance with MACT 
from startup. While any source in the low-risk subcategory is out of 
compliance with MACT if EPA is sued and judged to have wrongly approved 
the source's LRD, pre-startup LRD might be subject to more scrutiny by 
the public and more likely to face a challenge if the LRD was 
insufficient. Sources choosing option 2 could also be challenged for 
operating in violation of the MACT standard before EPA determines they 
are part of the low-risk subcategory.

L. Legal Issues With Title V Implementation Mechanism

    Comment: One commenter believes the title V implementation approach 
for the CAA section 112(c)(9) low-risk exemptions adopted in the final 
rule: (1) Attempts to create specific and federally enforceable legal 
requirements, without notice-and-comment rulemaking, through an 
informal exemption ``letter approval'' process conducted between a 
source and EPA; (2) imposes those legal requirements upon States and 
the public by employing a State-issued title V permit to establish 
applicable requirements; (3) does so without providing States or the 
public with any meaningful, legal opportunity to

[[Page 8362]]

comment on or challenge those requirements; and (4) does so all in 
contravention of existing EPA legal interpretations and policy that 
prohibit use of title V permits for such purposes. The commenter stated 
that EPA does not identify another instance in which a statutorily-
required determination by the Administrator achieves its culmination 
and embodiment in a title V permit, nor does EPA identify statutory 
authority in CAA section 112 or title V indicating Congressional intent 
to allow such a result. The commenter believes that this result 
transgresses title V's function to incorporate pre-existing federally 
enforceable applicable requirements into operating permits issued by 
approved permitting authorities, following applicability determinations 
by the approved permitting authority. The commenter stated that unlike 
the Prevention of Significant Deterioration (PSD) or New Source Review 
(NSR) permitting programs in which the rules contain criteria that are 
subsequently rendered applicable requirements in federally enforceable 
preconstruction permits, the risk exemption approval process gives 
definition and content to the qualifying conditions in an 
unenforceable, legally meaningless letter. The commenter noted that the 
State authorities do not render the low-risk approvals, have no 
ownership over them, and have no reason to stand behind them. The 
commenter stated that the public does not have the public comment, 
challenge, and petition opportunities afforded under title V for 
ordinary State applicability determinations.
    Finally, the commenter noted that governing EPA statutory and 
regulatory interpretations prohibit the title V implementation approach 
employed in the final rule. If the risk determinations, parameters, and 
conditions exist exclusively in a title V permit and the title V permit 
expires, the parameters and conditions of the risk exemption would no 
longer exist as a legal matter. The existence of a legal document 
independent of title V preserves the ability of permitting authorities 
and EPA to reopen title V permits that failed to include all relevant 
permit terms or to make corrections upon permit renewal. Also, title V 
regulations allow a permitting authority to include a ``permit shield'' 
stating that compliance with the conditions of the permit shall be 
deemed compliance with any applicable requirements as of the date of 
permit issuance.
    Three other commenters believe that title V permits represent an 
appropriate implementation mechanism for ensuring that low-risk sources 
never exceed the applicable risk thresholds. One of the commenters 
agrees that a significant title V permit modification is suitable for 
incorporating low-risk parameters. The commenter stated that the reason 
that a significant permit modification would be needed to incorporate 
the low-risk subcategory demonstration is found in 40 CFR 
70.7(e)(2)(i)(A)(3), a minor permit modification ``gatekeeper,'' which 
prohibits use of minor modification procedures where a provision would 
require (or change) a case-by-case determination during the title V 
permit process. The commenter believes title V is not creating the 
applicable requirements, rather relevant low-risk parameters are 
requirements grounded in appendix B to subpart DDDD.
    Another commenter stated that the title V process envisioned by the 
final rule is comparable to the synthetic minor permit process which 
has been in use for years. The commenter believes that CAA section 
112(c)(9) does not specify any mechanism whatsoever for ensuring that 
sources in delisted categories remain below applicable risk thresholds. 
Once they are delisted, emissions (and risks) can increase without 
limitation unless and until EPA takes affirmative action to relist the 
source category or subcategory. Here, however, EPA is mandating that 
any source seeking inclusion in the low-risk subcategory agree to 
enforceable permit conditions to ensure that the source continues to be 
low-risk. The commenter argued that the procedure envisioned here is 
virtually identical to the ``applicability determination'' process 
under title IV of the CAA. The commenter believes the petitioner's 
argument that the approach transgresses title V's function is based on 
a misperception of how the risk-based approach would be implemented. 
The commenter stated that EPA's approval of the LRD will be conditioned 
on retention of relevant source parameters that are necessary to ensure 
that the source remains low-risk. These parameters become federally 
enforceable requirements that properly are included in the title V 
permit.
    Response: The EPA agrees that the commenter who objected to the use 
of title V permits as an implementation tool in the low-risk process 
reflects a fundamental misunderstanding of what is required by the CAA 
in the delisting context with respect to sources who become no longer 
subject to section 112 emission standards. The EPA also agrees that the 
objecting commenter fails to appreciate the added confidence in the 
process afforded by the use of title V permitting procedures. Nothing 
in section 112(c)(9) of the CAA directs EPA to impose any further 
substantive or procedural requirements on sources in source categories 
or subcategories that are delisted. Under the CAA, such sources may 
permissibly be released from all obligations under section 112(d) of 
the CAA with respect to control of HAP emissions. Moreover, in 
determining whether an individual source is a member of one source 
category versus another subcategory, even while one is listed and 
subject to section 112(d) standards and the other is not, nothing in 
the CAA requires EPA to subject that decision to notice and comment 
rulemaking or to federally establish directly enforceable requirements. 
Given that, EPA could have theoretically adopted an approach that 
relies upon source and EPA application of the appendix B to subpart 
DDDD criteria for determining eligibility for the low-risk subcategory 
that, upon EPA approval of a source's LRD, subsequently releases the 
source from any further obligations related to the PCWP NESHAP. 
However, in order to better ensure that low-risk PCWP sources remain 
low risk following the factual findings necessary to approve their LRD, 
EPA chose to further require (and sources have accepted) significant 
continuing conditions, the failure to meet which will result in low-
risk sources having to return to the PCWP MACT category. The best 
mechanism for imposing these conditions is the title V permit process, 
which can be used to establish as binding enforceable requirements 
terms and conditions that do not otherwise exist as CAA applicable 
requirements. The EPA has long held that the title V process can be 
used to establish enforceable limitations on the potential to emit air 
pollution, for example, in Indian country where there may otherwise be 
an absence of regulatory controls. Moreover, EPA's title V regulations 
have long provided for what types of permit modifications must occur to 
specifically accommodate changes that ``establish or change a permit 
term or condition for which there is no underlying applicable 
requirement and that the source has assumed to avoid an applicable 
requirement to which the source would otherwise be subject.'' See 40 
CFR 70.7(e)(2)(i)(A)(4). In the low-risk PCWP context, we believe that 
this authority is directly applicable to this situation where we are 
conditioning a source's continuing low-risk eligibility upon its 
assumption of enforceable terms and conditions reflecting its low-risk 
parameters, taken in order to avoid the

[[Page 8363]]

PCWP MACT requirements that would otherwise apply. As a policy matter, 
we believe this provides far better assurance that low-risk sources 
will remain so than would merely releasing them from all further 
obligations with respect to the NESHAP, and in light of the language of 
our title V regulations, we cannot accept the objecting commenter's 
view that imposing these conditions is not legally permissible.
    Turning to the objecting commenter's specific complaints, we 
therefore disagree that the process attempts to create specific and 
federally enforceable requirements without notice and comment 
rulemaking through an informal approval process between the source and 
EPA. The process that occurs between the source and EPA is limited to 
EPA's review and approval or disapproval of the source's LRD submitted 
in support of its applicability determination request, and EPA's 
forwarding of approved low-risk parameters to the State permitting 
authority. The State's subsequent conversion of those parameters into 
enforceable terms and conditions is very much a notice and comment 
process.
    Regarding the objection that the legal requirements for sources to 
maintain low-risk eligibility imposes those legal requirements on 
States and the public, it is, of course, under the principles of 
federalism embodied in the CAA, always within the States' legal rights 
to require a more stringent emission limitation for any PCWP source 
than is otherwise required by our rule, including requiring any low-
risk PCWP source to meet MACT. See CAA section 116. In terms of 
burdening the public, presumably in having to participate in the title 
V permitting process (should the member of the public so choose), it is 
not apparent what alternative the objecting commenter would prefer. We 
assume that the commenter would not have us, for example, revise our 
title V rules to allow these changes to occur without the opportunity 
for public comment. We disagree that the process provides no meaningful 
opportunity to comment on low-risk parameters or their subsequent 
incorporation as terms and conditions in permits. First, EPA's approval 
of a source's LRD is a judicially reviewable final action under CAA 
section 307(b), as is any applicability determination under CAA section 
112. Second, to provide better assurance that sources remain low risk 
than is absolutely required under CAA section 112(c)(9), we are 
requiring that the notice and comment permit issuance process be used 
to implement this need for assurance.
    The EPA wishes to clarify the characterization of the low-risk 
parameters that result from the LRD approval process, especially in 
comparison to our recently finalized reconsideration and amendments of 
the Boilers/Process Heaters rule. In the Boilers/Process Heaters rule, 
in response to comments, we explained that the more appropriate title V 
regulation references of authority for incorporating the section 
112(d)(4) compliance option are Sec.  70.7(e)(2)(i)(A)(3), regarding 
establishment or changes of case-by-case determinations of an emission 
limitation or other standard, and Sec. Sec.  70.7(f) and (g), regarding 
permit reopenings to incorporate new applicable requirements. This is 
because, unlike in the PCWP context, in the Boilers/Process Heaters 
rule, a source's choice of the risk-based compliance option is an 
alternative standard and an ``applicable requirement'' in the same 
manner as the MACT-based emission limitations in the Boilers/Process 
Heaters rule. However, in the PCWP context, prior to a source's 
obtaining a title V permit that reflects its EPA-approved low-risk 
parameters, the only enforceable applicable requirements relating to 
the PCWP NESHAP are the MACT standards themselves, as there is no 
alternative health-based compliance option within the standard itself. 
Rather, by the nature of the section 112(c)(9) delisting and exemption, 
a low-risk PCWP source assumes enforceable terms and conditions only 
through the title V permit process, taken as a condition for their 
continuing eligibility in the subcategory and avoidance of the PCWP 
MACT to which they would otherwise be subject. Therefore, for the PCWP 
low-risk subcategory, we continue to regard 40 CFR 70.7(e)(2)(i)(A)(4) 
as the relevant ``gatekeeper'' requiring changes to title V permits 
incorporating low-risk parameters to be made through the significant 
permit revision process. Moreover, since the low-risk parameters sent 
from EPA to State permitting authorities are not directly enforceable 
``applicable requirements,'' unlike in the Boilers/Process Heaters 
rule, we do not regard the permit reopening provisions of 40 CFR 
70.7(f) and (g) as being relevant. While, of course, under CAA section 
112(c)(9) EPA could have chosen the statutorily permitted option of 
requiring no creation of enforceable terms and conditions at all 
following approval of a source's LRD, we have chosen to require the 
extra step of a process that is closer to that for other programs that 
apply to source efforts to limit the potential to emit. While the 
objecting commenter is dissatisfied that the process is not identical 
to those for Prevention of Significant Deterioration (PSD) or New 
Source Review (NSR), which both involve creation of enforceable 
requirements in preconstruction permits before they are incorporated 
into title V permits, we are frankly surprised that the commenter does 
not appear to appreciate the extra assurance we have obtained in 
requiring approved low-risk sources, notwithstanding their exemption 
from section 112(d) standards, to assume enforceable terms and 
conditions even though such is not required under section 112(c)(9).
    Regarding the objecting commenter's points about the potential 
expiration of permits and the function of the title V ``permit 
shield,'' we do not regard these arguments as being valid reasons to 
choose to abandon title V as an implementation tool for the low risk 
approach, particularly since the logical alternative and clearest way 
to avoid the problems raised by the commenter is to require nothing 
further of low-risk PCWP sources once EPA approves their LRD and 
determines they are eligible for the delisted low-risk subcategory. In 
any case, once the source is in the subcategory, the section 112(d) 
standard no longer applies to the source and therefore a permit's 
expiration or the existence of its permit shield poses no potential 
conflict with the PCWP NESHAP. Instead, in order to ensure that it 
validly remains in the delisted low-risk subcategory, it is imperative 
on the source to ensure that it maintains a valid title V permit 
reflecting its low-risk parameters; otherwise it will fail to maintain 
low-risk eligibility and will have to comply with MACT.

M. Timing of Title V Permit Revisions

    Comment: One commenter strongly supported EPA's proposal to require 
only the submittal of a facility's low-risk parameters to its 
permitting authority for incorporation into its title V permit (as 
opposed to having the title V permit revisions actually incorporated 
into the permit). The commenter stated that sources do not have any 
control over the amount of time that it takes for State permitting 
authorities to review and act upon requests for permit modifications. 
In addition, the commenter noted that this approach is consistent with 
the permit application shield provision of part 70 and the Boilers/
Process Heaters rule's health-based compliance alternatives. The 
commenter also noted that the source is entirely responsible for 
ensuring that it remains in compliance with the relevant operating

[[Page 8364]]

parameters that are to be included in the title V permit, even before 
that permit is issued.
    Two commenters disagreed with the proposal to allow facilities to 
qualify for the low-risk subcategory merely based upon submission of a 
title V permit revision application. Both commenters stated that EPA's 
approach violates title V, the part 70/71 regulations, and 
corresponding State laws. The commenters noted that many existing 
facilities subject to the PCWP MACT already will have permit terms and 
conditions subjecting the entire facility to the standard as a result 
of earlier permit revisions or renewals. The commenters stated that 
until the title V permits are revised to incorporate enforceable 
conditions into permits, sources must remain subject to the MACT 
standard. The commenters believe allowing a facility to become part of 
the low-risk subcategory before the State or local permitting authority 
approves the necessary permit revision undermines the role of the 
permitting authorities. The commenters also argued that the proposal 
makes the significant permit modification process and public 
participation meaningless.
    Response: The EPA believes that the objecting commenters are 
confusing the EPA's role in reviewing LRD and determining source 
eligibility to join the low-risk subcategory with the State permitting 
authority's role in making sure permits currently reflect applicable 
requirements. We are providing greater assurance than is strictly 
required by CAA section 112(c)(9) that sources will remain low risk 
following EPA LRD approval. We are requiring that sources timely submit 
permit revision applications that reflect their low-risk parameters for 
future incorporation as enforceable terms and conditions. We believe 
this requirement will help ensure that such sources continue to operate 
under the conditions that proved them to be low risk. In cases where a 
PCWP source's permit already reflects the PCWP MACT requirements and 
the MACT compliance deadline has passed, of course, timely amendment of 
the permit itself will be needed in order to allow the source to 
alternatively operate according to its low-risk parameters. Until the 
permit is actually revised, the source will have to comply with its 
then-applicable terms and conditions, even if they reflect MACT and the 
source's LRD has been approved by EPA. But we do not regard this 
practical problem as being sufficiently severe to merit abandoning the 
additional assurance requirement entirely, or even being one that 
sources and title V permitting authorities may commonly face when 
permit terms become obsolete in the face of new applicable 
requirements.
    Comment: Two commenters argued that State and local permitting 
authorities have the right to thoroughly review and disapprove LRD if 
they are incomplete or incorrect. However, the final rule does not 
clearly specify that State and local permitting authorities have this 
right, and it does not specify that a source must comply with the 
emission limits and requirements of the NESHAP if the demonstration is 
not approved by the State and local authority. The commenters noted 
that without reviewing the LRD, a State or local agency would be unable 
to defend granting an exemption to a facility during a public review 
process. The commenters noted that many State and local agencies will 
find it necessary to review the risk-based exemptions, and the process 
could place a very intensive resource demand on State and local air 
agencies that must verify extensive emissions and stack information and 
review the risk assessments to ensure that they have been done 
properly. The review of these risk assessments would require expertise 
in risk assessment methodology that State and local agencies may not 
possess.
    Response: We acknowledge that review of the eligibility 
demonstrations for the delisted low-risk subcategory would require 
resources for verification of information and may require expertise in 
risk assessment methodology that is not yet available in some States. 
To alleviate these concerns, we will review and approve/disapprove the 
low-risk subcategory eligibility demonstrations submitted by PCWP 
facilities. The burden to States of assuring that affected sources 
continue to be low-risk will be no more than the burden associated with 
ongoing title V enforcement because the parameters that define a source 
as low-risk will be reflected in terms and conditions to be 
incorporated into the title V permit.
    Notwithstanding an EPA finding that a source is eligible for 
inclusion in the low-risk subcategory, States are free, consistent with 
CAA section 116, to impose more stringent limitations on a low-risk 
source, including the requirements of this PCWP NESHAP that would 
otherwise apply if the source had not been found to be low risk. These 
requirements can be imposed on a State-devised schedule, and might even 
include provisions for independent State review and approval of LRD. 
The State might determine whether technical problems suggest that the 
source may not in fact be low risk, notwithstanding EPA's approval of 
the source's LRD. However, under the final rule, unless a State chooses 
to involve itself in the decision of whether a source is low risk, EPA 
approval of an LRD and the source's submission of a permit revision 
application are sufficient for the source to join the low-risk 
subcategory. In order to avoid an over-burdening of State resources, we 
have maintained the approach that relies upon EPA review and approval 
of LRD, and we depend upon States' inherent authority to require more 
of themselves and of sources, under CAA section 116, for those States 
that choose to do so.
    Comment: One commenter stated that there is a possibility that in 
some cases, EPA's LRD approval action will be too late for a facility 
to submit its title V application before the MACT compliance deadline. 
The commenter requested that a facility be allowed to submit its title 
V application incorporating the emission rate and process limitations 
stated in the LRD concurrent with or soon after the submittal of the 
LRD to EPA.
    Response: We disagree that the approach suggested by the commenter 
is appropriate. In the case of any LRD, we expect there will be the 
need to provide additional information or to correct aspects in initial 
submissions, and we do not think it is reasonable for permit 
applications to be based on these unreviewed, uncorrected LRD, 
especially since submission of a permit application starts a clock 
under State title V programs with a deadline for the permitting 
authority's action. While the problem identified by the commenter may 
prove to be a real one in specific cases, we have generally determined 
that the best way to ensure that low-risk sources remain low risk and 
that terms and conditions accurately reflect their status is to require 
that permit revision applications reflect EPA-approved LRD. Thus, it is 
important that sources submit their LRD sufficiently early to EPA so 
that ``last-minute'' review does not jeopardize the source's chances of 
becoming a low-risk source before the MACT compliance deadline, if that 
is the source's goal. Of course, in light of our other changes that 
extend the MACT compliance deadline and allow sources to become low 
risk after the MACT compliance deadline passes, we consider this 
problem to not be as severe as suggested by the commenter.

N. Permit Conditions

    Comment: Two commenters requested that the number of parameters to 
be included in title V permits for low-risk sources be minimized to 
allow operational flexibility. One commenter stated that section 11(b) 
of appendix B

[[Page 8365]]

to subpart DDDD should ensure that the low-risk requirements continue 
to be met, but not impose cumbersome monitoring, recordkeeping, and 
reporting requirements with little environmental benefit. In 
particular, the commenter is concerned that the list of dispersion 
modeling parameters (such as stack height, stack temperature, and stack 
flow) can change without changing the overall conclusion of a risk 
analysis. The commenter stated that if parameters are too specific, 
every change to one of those parameters would require a revision to the 
site-specific risk assessment and a title V permit action before the 
source has regulatory permission to make the change. The commenter 
recommended that only conditions that refer to the health effects 
criteria established in appendix B to subpart DDDD be included.
    Another commenter requested that EPA clarify that permits primarily 
should specify an emission limit and should restrict production rates 
only to the extent that they impact the plant's emission limit. The 
commenter noted that facilities will attempt to achieve highest 
production rates in combination with worst-case operating parameters 
during testing, but in practice, it can be difficult to reach worst-
case conditions. The commenter stated that EPA should clarify that 
facilities can extrapolate the production rates and operating 
conditions measured during performance tests to ``true'' worst-case 
emissions scenarios for purposes of their operating permit limits.
    Response: Our intent is that parameters incorporated as limits into 
a source's title V permit will be those parameters that determine the 
source's risk level. This will ensure that sources in the low-risk 
subcategory continue to operate in a manner that is consistent with 
their LRD. The results of a risk assessment for a particular source 
depend on many factors, including the emission rates and dispersion 
parameters associated with each process unit at the facility. Process 
unit emission rates are a function of production rate and the 
effectiveness of any emissions controls used. Process unit emission 
rates can also be impacted by other process-related parameters (e.g., 
process unit operating temperature, dryer firing method, fuel type, 
wood type, resin HAP content, etc.), but the effect of these parameters 
on emission rate is not as well defined as that of production rate and 
control system effectiveness. Therefore, we disagree with the notion of 
simply extrapolating emission rates based on process-related parameters 
other than production rate. However, we agree that emission rates can 
be reported in terms of production (i.e., as emission factors) and that 
production rate can be used to extrapolate to worst-case emission rates 
(provided that all other worst-case conditions remain the same as 
during the emissions test). The language in appendix B to subpart DDDD 
does not prevent such scaling of emission rates to account for 
increased production.
    We maintain that production rate and other indicators of emission 
rate should be incorporated as limits into title V permits. This is 
because the requirement to memorialize the low-risk parameters as 
enforceable title V permit terms and conditions is a condition, under 
our rule, for eligibility in the low-risk PCWP subcategory established 
under CAA section 112(c)(1) and delisted under section 112(c)(9). Thus, 
while the effect of the determination that a source is low risk is to 
exempt it from other section 112 requirements, the requirement to 
assume title V permit conditions to maintain low-risk status is itself 
based on our implementation of section 112(c), and is a necessary 
condition a source must satisfy as an eligibility criterion for joining 
the low-risk subcategory. Sources that fail to meet this condition 
cannot maintain low-risk eligibility.
    Appendix B to subpart DDDD does not require continuous measurement 
of process unit emission rates. Therefore, indicators of process unit 
emission rate must be documented on an ongoing basis to provide 
assurance that the actual emission rates used to establish the source 
as a member of the low-risk subcategory have not changed. Indicators of 
emission rate include process unit throughput, control device operating 
parameters (monitored as required in section 5(e) of appendix B) if a 
control device is used, and other pertinent process unit operational 
parameters depending on the type of process unit. These indicators of 
emission rate are appropriate title V permit conditions because, during 
an inspection, permitting authorities can readily monitor indicators of 
emission rate but cannot easily measure actual source emissions. 
Therefore, prior to increasing production rate above the level in a 
source's permit (or deviating from other permit conditions in a way 
that could result in HAP emissions above the levels used to establish a 
source as a member of the low-risk subcategory), that source must 
revisit its LRD and demonstrate that it continues to qualify for the 
low-risk subcategory at the higher production rate.
    In addition, because our goal is to ensure that risks posed by a 
facility are maintained at a level at or below those in the facility's 
LRD, it is also necessary to include certain dispersion parameters as 
title V permit conditions. Stack height is an important dispersion 
parameter for the risk demonstration and should be included as a permit 
condition. If stack height is already incorporated into the title V 
permit independent of the LRD, then this parameter should be linked 
explicitly to the LRD so that stacks cannot be modified without 
revisiting the demonstration. We have also included stack height in 
section 11(b) of appendix B to ensure it is included as a permit 
condition for those facilities that do not already have stack height 
incorporated into their title V permits. We agree that it is not 
necessary to include stack temperature and exhaust flow rate as title V 
permit conditions because these parameters are not likely to change 
considerably in a way that would increase risks without an associated 
change in other parameters for which title V permit limits will be 
established (i.e., process throughput, control device operating 
conditions if a control device is used, or other pertinent process 
conditions).
    We believe appendix B to subpart DDDD already allows operational 
flexibility while ensuring that sources operate in a manner that is 
consistent with their LRD. For example, appendix B to subpart DDDD does 
not include any process unit parameter monitoring, reporting, or 
recordkeeping requirements. Thus, monitoring, recordkeeping, and 
reporting requirements must be developed by a permitting authority and 
then incorporated into a facility's title V permit in order to ensure a 
facility's compliance with its LRD. Additionally, the requirement that 
the LRD be based on worst-case operating conditions provides facilities 
with operational flexibility because if a source meets our low-risk 
requirements while operating under worst-case conditions, then the 
source should also meet those criteria when operating under any other 
conditions. Finally, section 5(h) of appendix B clarifies that 
facilities can use emission rates in their LRD that are more 
conservative than worst-case conditions in order to further increase 
their operational flexibility.

O. Costs and Benefits of Establishing a Low-Risk Subcategory

    Comment: One commenter stated that EPA should revise the cost-
benefit analysis to accurately reflect the lack of public health 
protection resulting from the low-risk subcategory. Another commenter 
charged that EPA's own data

[[Page 8366]]

reveal that the risk-based exemptions in the final PCWP rule have a 
substantially higher net social cost than a lawful MACT standard 
without the exemptions, and also result in significantly higher 
emissions of HAP, volatile organic compounds (VOC) and PM than a rule 
without exemptions. The commenter noted that the preamble to the rule 
admitted that the exemptions could increase HAP emissions by 4,400 tons 
per year (tpy), when compared to requiring all plants to meet pollution 
control requirements. The preamble also acknowledged that exposure to 
the HAP released by the PCWP industry have been linked to extensive 
noncancer health effects but the Regulatory Impact Analysis (RIA) for 
the final rule did not assign an economic value to these very serious 
health impacts.
    The commenter stated that the Office of Management and Budget (OMB) 
has recognized and published estimates of the cost to the public health 
associated with exposure to each ton of PM or VOC, but EPA did not 
attempt to quantify the public health costs associated with higher 
increases of these pollutants. The commenter stated that even using the 
lowest end of the monetized benefits published by OMB, the value of 
reducing VOC and PM emissions from all PCWP plants exceeds the savings 
to industry under the exemptions in the final rule.
    The commenter noted that EPA estimated that requiring all PCWP 
plants to reduce HAP would result in incidental increases in nitrogen 
oxide (NOX) emissions, but EPA made no attempt to compare 
this potential increase to the additional emissions of HAP, VOC, and PM 
that would result from the exemptions. The available evidence suggests 
that the NOX increases are relatively trivial, especially 
when compared to the additional pollution authorized by the rule's 
exemptions. Nitrogen oxide is a pollutant of concern because it is a 
precursor in the formation of ground-level ozone. But the exemptions 
that EPA has adopted could increase emissions of VOC (another critical 
ozone precursor) by as much as an estimated 13,000 tpy. Arbitrarily, 
neither the RIA nor the preamble explains why increasing VOC by 13,000 
tpy to avoid 1,200 tpy of NOX would yield a net benefit in 
reducing ozone formation.
    Similarly, the Final RIA notes that NOX can form fine 
PM, but the exemptions in the rule actually could result in an increase 
in PM of 6,100 tpy. Based on their calculations using OMB cost-benefit 
values, the commenter contended that the reduction in NOX 
emissions does reduce public health costs, but the increase in VOC and 
PM emissions results in an increase in public health costs anywhere 
from 44 to 414 times higher than the public health savings from the 
NOX reductions from the exemptions.
    In addition, the commenter cited internal EPA documents and stated 
that the decision to include risk-based exemptions appears to have been 
driven by the desire to lower the cost of the rule, which contradicts 
the ruling in National Lime Assn v. EPA, 233 F.3d 625, 640 (D.C. Cir. 
2000) that cost may only be taken into account when considering beyond-
the-floor emissions limitations.
    Other commenters disagreed and believe there is little sense in 
requiring a facility to undertake costly control expenditures when it 
does not pose a significant risk to human health or the environment. 
One commenter disagreed that the increased HAP emissions resulting from 
the low-risk subcategory will impose significant risks on the general 
public because, by definition, a source cannot qualify for the low-risk 
subcategory unless it does not impose any meaningful risks on the 
general public.
    The commenter also disagreed with the petitioners' claim that EPA 
should have quantified the potential health benefits of the collateral 
VOC and PM reductions that would have resulted if low-risk sources were 
required to install controls. The commenter argued that while there may 
be health benefits to reducing PM or VOC, to the extent that reductions 
in these criteria air pollutants are needed, the proper vehicle is 
title I of the CAA, not through a title III HAP regulation. The 
commenter believes it is improper to justify HAP regulation under title 
III solely by the fact that there may be incidental benefits from 
criteria pollutant reductions.
    The commenter stated that the costs of the rule outweighed the 
benefits for low-risk sources. According to the commenter, the 
incinerator controls that would be necessary in most cases to meet the 
rule would cause increased energy demand and a sharp increase in the 
annual emissions of some criteria pollutants from facilities. The 
commenter disagreed with the petitioners' claim that increased 
NOX emissions are outweighed by the reductions in VOC. The 
commenter stated that most PCWP facilities are in NOX-
limited areas, such that any increase in NOX has the 
potential to increase ozone formation, whereas emissions of VOC do not.
    The commenter also disagreed with the petitioners' argument that 
EPA's evaluation of costs and benefits in analyzing whether to 
implement the low-risk subcategory ``runs afoul of National Lime Ass'n 
v. EPA, 233 F.3d 625, 640 (D.C. Cir. 2000),'' which held that costs may 
be considered only when setting ``above the floor standards.'' The 
commenter noted that the Court's decision in that case was made solely 
with reference to CAA section 112(d), and EPA here has created a 
subcategory pursuant to 112(c)(1) and delisted it pursuant to CAA 
section 112(c)(9).
    Response: In the RIA for the final rule, we quantified the social 
costs of the final standard but did not quantify the change in social 
costs that would result from application of the low-risk subcategory. 
Based on the results of economic impact analyses for other MACT 
standards in general, it is likely that the change in social costs (in 
this case, without an estimate of benefits) is approximated by the $66 
million reduction in compliance costs that is estimated in the 
supporting information for the final rule and mentioned in Appendix A 
of the RIA. All assumptions underlying emissions estimates related to 
the low-risk subcategory are found in the supporting information for 
the final rule.
    We explain in Chapter 6 of the RIA that we did not provide a 
monetized value for the benefits from reduced health effects from HAP 
reductions associated with the final rule due to a lack of sufficient 
scientific data. The state of science in this area is still in that 
position today. Use of a benefit transfer approach as suggested by 
commenters is not appropriate in this case. We are continuing our 
analytical work to address the uncertainty in a benefits transfer 
approach. We did not provide estimates of the monetized benefits 
associated with the VOC emission reductions since we did not have 
sufficient air quality modeling runs available to allow us to estimate 
these benefits and because we did not have sufficient scientific data 
to place a monetized benefit value on these reductions. The OMB has 
prepared benefits estimates for VOC emission reductions in its annual 
Thompson Reports (reports on benefits and costs of Federal Agency 
regulations), but these estimates represent broad, general estimates of 
the monetized value for these reductions and not benefits of VOC 
emission reductions from sources affected by this final rule. This same 
point regarding the generalized foundation upon which the Thompson 
Report estimates rest may be made for our not providing monetized 
benefits for

[[Page 8367]]

the fine PM emission reductions. For the same reasons we did not 
estimate monetized benefits for the rule, we did not estimate monetized 
disbenefits associated with the low-risk subcategory (e.g., additional 
NOX emissions associated with RTO operations): A lack of 
sufficient scientific data to assign a monetized benefits value for HAP 
reductions, a lack of sufficient air quality modeling runs and 
sufficient scientific data to assign a monetized benefits value for VOC 
reductions, and the generalized foundation upon which the Thompson 
Report estimates are based for PM reductions.
    It should be noted that we could only consider HAP emissions in 
setting the final standards as per the requirements of CAA section 112. 
Quantification of benefits and disbenefits are requested in OMB's RIA 
guidelines but are not legally required information for setting MACT 
standards.
    We disagree with the assertion that our consideration of costs, in 
the context of establishing and delisting the low-risk PCWP 
subcategory, violates the DC Circuit's decision in National Lime. In 
setting the MACT floors for the PCWP NESHAP, cost was not a factor, and 
costs of compliance may not be used under the PCWP NESHAP as a basis 
for avoiding MACT, if it otherwise applies. Sources will be able to 
avoid MACT only if they demonstrate that they are in fact low risk. 
There is nothing improper about our general desire to reduce costs of 
CAA compliance, where appropriate and where imposing those costs is not 
necessary. In fact, the very existence of CAA section 112(c)(9) 
reflects the basic congressional goal of avoiding imposing regulatory 
burden where that burden is not needed to provide an ample margin of 
safety to protect public health.

III. Responses to Comments on the Proposed Amendments and 
Clarifications for Subpart DDDD

A. Definitions

1. Dryer Definitions
    Comment: One commenter stated that the definition of ``tube dryer'' 
should be amended to differentiate tube dryers from pneumatic conveyors 
that use conditioned air. The commenter provided a suggested revised 
definition of ``tube dryer.''
    Response: We did not intend to include pneumatic fiber transport 
systems under subpart DDDD. Pneumatic fiber transport systems are 
distinguished from primary and secondary tube dryers because heat is 
added to dryers specifically to remove moisture while the purpose of 
the higher temperatures used in fiber transport systems is to prevent 
cooling. Therefore, we have amended the definition of ``tube dryer'' as 
requested to ensure that pneumatic fiber transport systems are not 
classified as tube dryers.
    Comment: One commenter requested that EPA modify all of the dryer 
definitions in subpart DDDD and appendix B to subpart DDDD by replacing 
``at elevated temperature'' with ``by applying heat.''
    Response: We agree with the commenter's suggested changes to the 
dryer definitions to clarify that heat is deliberately applied during 
drying processes. The final rule has been amended as requested by the 
commenter.
2. Affected Source and Direct-Fired Process Unit
    Comment: One commenter requested that EPA consider modifications to 
the proposed amendments to the definitions of ``combustion unit'' and 
``affected source.'' First, the definition of ``combustion unit'' 
should be modified (1) to include combustion units that direct-fire 
PCWP process units but are not used to combust HAP emissions, and (2) 
for consistency with broad references in the proposed amendments that 
define the source category. Alternatively, the commenter suggested a 
revision to the proposed amendment to the definition of ``affected 
source.''
    Second, the use of the word ``directly'' in the definition of 
``direct-fired process unit'' could exclude process heaters that 
indirectly heat a heat transfer media before the combustion exhaust is 
routed to the drying operation, where the remaining heat energy is used 
in direct-fire contact with the process material. The commenter stated 
that deleting the word ``directly'' from the definition of ``direct-
fired process unit'' would not change the meaning of the definition 
because it would still include the phrase ``* * * such that the process 
material is contacted by the combustion exhaust.''
    Response: After reviewing how the term ``combustion unit'' is used 
throughout subpart DDDD, we agree with the commenter's suggested 
amendment to the definition to ``combustion unit'' to clarify that 
combustion units can be used to direct-fire process units or to control 
process exhaust. The amended definition of ``affected source'' (which 
we are amending as proposed with no further revisions) includes only 
those combustion unit exhaust streams that direct-fire process units, 
and it should not be read to mean that all combustion units at the 
plant site are part of the PCWP affected source (and thereby exempt 
from the Boiler/Process Heaters rule). We also agree with the commenter 
that an exhaust stream that supplies indirect heat for other uses would 
be part of the PCWP affected source if it is eventually routed through 
the direct-fired dryers such that it too contacts the wood material and 
becomes a mixture of combustion gases and process gases. We have 
amended the definition of ``direct-fired process unit'' accordingly as 
suggested by the commenter. However, if the indirect heat exhaust 
stream does not routinely pass through the direct-fired dryers, then 
this exhaust stream would be subject to the final Boilers/Process 
Heaters rule.
3. Engineered Wood Products
    Comment: One commenter requested several edits to the definition of 
``engineered wood product.'' First, the commenter stated that the type 
of resin or glue and the designed use of the product should not be 
specified for consistency with the definitions for the other wood 
products. Second, the list of products should include parallel strand 
lumber. Although implicit in the rule since the definition of 
``laminated veneer lumber'' includes parallel strand lumber, parallel 
strand lumber is the more commonly used term.
    Response: We agree with the commenter that, for consistency with 
other definitions in subpart DDDD, the definition of ``engineered wood 
products'' need not mention specific resin types or the designed use of 
the products. We have also removed the reference to glue from the 
commenter's suggested definition because ``resin'' is defined elsewhere 
in subpart DDDD, and the definition of ``resin'' includes ``glue.'' We 
have also added the term ``parallel strand lumber'' to the definition 
of ``engineered wood products.'' Finally, we have revised the 
definition of ``laminated veneer lumber'' and added a new definition of 
``parallel strand lumber'' to indicate that these are two terms for the 
same product.
    Comment: One commenter requested that the definitions of ``LSL 
press'' and ``LVL press'' be revised to clarify that the material 
exiting these presses is a billet that must be sawn into LVL, LSL, or 
PSL and that not all LVL presses are heated. The commenter provided 
suggested revisions to these definitions.
    Response: We agree with the commenter that LSL and LVL presses form 
billets that are subsequently cut into LSL and LVL products and amended 
the definitions to reflect that clarification. We further edited the 
definition of ``LVL press'' to more explicitly include PSL.

[[Page 8368]]

B. Applicability of the PCWP Rule to Lumber Kilns Drying Utility Poles

    Comment: One commenter expressed support for EPA's proposal to 
expand the definition of lumber dry kilns to include kilns used to dry 
utility poles, and two commenters suggested definitions of ``lumber.''
    Response: We requested both comments and additional data to either 
support or refute the treatment of kilns used to dry utility poles as 
lumber kilns subject to subpart DDDD, and we received one supporting 
comment and no additional data on this subject. Therefore, we have 
concluded that lumber kilns drying utility poles are subject to the 
rule (but have no control or work practice requirements), and we have 
added a definition of ``lumber'' to Sec.  63.2292 based on commenters' 
suggestions.

C. Capture Efficiency Determination

    Comment: One commenter had previously requested clarification from 
EPA regarding the use of the capture efficiency value and measuring 
capture efficiency on unenclosed, uncontrolled presses. The commenter 
supported EPA's adoption of the proposed amendment for line 10 of both 
table 4 to subpart DDDD and table 2B to appendix B to subpart DDDD but 
questioned how to handle fugitive emissions from a press enclosure or 
board cooler, which is important when using a partial enclosure to meet 
the low-risk criteria.
    The commenter also stated that EPA should improve the consistency 
throughout the rule regarding emission rate determinations whether a 
press or cooler has a control device on it or not. The commenter stated 
that regardless of whether a control device is used, facilities should 
be allowed to use either the design specifications included in the 
definition of ``wood products enclosure'' or determine the percent 
capture efficiency of the enclosure to meet any of the compliance 
options and/or the LRD. The commenter requested that Lines 9 and 10 of 
both table 4 to subpart DDDD and table 2B to appendix B to subpart DDDD 
be combined into a single line with no distinction regarding whether 
emissions are treated in an add-on control device.
    Response: The reconstituted wood products production-based 
compliance option (PBCO) applies only to uncontrolled presses. When 
determining compliance with the PBCO, it is necessary to compare total 
press emissions to the PBCO limit. The total press emissions include 
press emissions discharged through the press vents plus any emissions 
that are not collected by the press vents but are discharged elsewhere. 
To determine the percentage of press emissions discharged through the 
press vents, it is necessary to measure capture efficiency and 
emissions from the press vents. Then total press (or board cooler) 
emissions are determined as follows for comparison to the PBCO limit: 
Total press emissions (lb/MSF \3/4\) = measured emissions 
(lb/MSF \3/4\)/capture efficiency.
    Reconstituted wood products press emissions discharged through 
press vents and press emissions discharged elsewhere (e.g., fugitive 
emissions) are part of the emissions from a PCWP affected source, and 
therefore, must be included in the LRD for the affected source. The 
portion of the emissions discharged through the press vents (measured 
emissions) can be modeled in the LRD as a point source. The capture 
efficiency of the press must be measured, and then the portion of press 
emissions that are to be modeled as a fugitive source can be calculated 
as follows: Fugitive press emissions (lb/hr) = (measured press 
emissions (lb/hr)/capture efficiency) - measured press emissions (lb/
hr).
    We disagree that the rows of table 4 to subpart DDDD and table 2B 
to appendix B to subpart DDDD pertaining to capture determination 
should be combined, but we have edited the second row pertaining to 
capture efficiency in each of these tables to address the commenter's 
concern. By definition, emissions must be routed to a control device in 
order for an enclosure to be a wood products enclosure or a Method 204 
permanent total enclosure (PTE). The definitions of wood products 
enclosure and PTE were written for situations where emissions are 
captured and routed to a control device. However, we agree that it 
would be reasonable to assume 100 percent capture if a permanent 
enclosure is installed such that all the design criteria for a ``wood 
products enclosure'' or a PTE are met except for the requirement to 
discharge to a control device.

D. Incorporation by Reference of NCASI Method ISS/FP-A105.01

    Comment: One commenter supported EPA's proposal the incorporate by 
reference NCASI Method ISS/FP-A105.01 as an alternative method for 
measuring emissions of acetaldehyde, acrolein, formaldehyde, methanol, 
phenol, and propionaldehyde.
    Response: Today's final action amends 40 CFR 63.14 by revising 
paragraph (f) to incorporate by reference one test method developed by 
the National Council of the Paper Industry for Air and Stream 
Improvement (NCASI): Method ISS/FP-A105.01, Impinger Source Sampling 
Method for Selected Aldehydes, Ketones, and Polar Compounds, December 
2005. The method is available from the NCASI, Methods Manual, P.O. Box 
133318, Research Triangle Park, NC 27709-3318 or at http://www.ncasi.org.
 It is also available from the docket for today's final 

action (Docket ID No. EPA-HQ-OAR-2003-0048). This document was approved 
for incorporation by reference by the Director of the Federal Register 
in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

IV. Responses to Comments on SSM Issues

    Comment: One commenter stated that there are several problems with 
the rule's SSM provisions. The provisions unlawfully permit sources to 
exceed emissions standards during SSM periods, are internally 
conflicting (paragraphs 63.2250(b) and 63.2271(b)), and limit public 
availability of sources' SSM plans.
    Response: As stated in the notice of reconsideration and in the 
proposed amendments, where the PCWP rule's SSM provisions mirror the 
SSM provisions in the General Provisions (40 CFR, part 63, subpart A), 
EPA will address comments on those provisions in the reconsideration 
and amendment process for the General Provisions, unless PCWP sources 
are somehow affected differently than other sources. The EPA has 
addressed the issue of excess emissions during periods of SSM as part 
of the General Provisions rulemaking process as well as in the 2004 
PCWP final rule's BID. The issue of public access is addressed in the 
2005 General Provisions notice of reconsideration and proposed 
amendments (70 FR 43992, July 29, 2005), and it will be further 
addressed in the upcoming General Provisions final amendment and 
reconsideration notice.
    In response to the comment that the final PCWP rule's SSM 
provisions are internally conflicting, we note that the recently 
proposed amendments to the General Provisions also included amendments 
to subpart DDDD. Instead of specifying that sources must demonstrate 
that they were acting in accordance with their SSM plan during periods 
of SSM, proposed Sec.  63.2271 specifies that sources must demonstrate 
that they were acting in accordance with Sec.  63.6(e) of the General 
Provisions during an SSM event. Therefore, when the General Provisions 
proposed amendments are finalized, most likely

[[Page 8369]]

in the Spring of 2006, there will no longer be any conflict within the 
PCWP rule's SSM provisions.
    Comment: Two commenters discussed the proposed amendment to Sec.  
63.2250(a), the section that describes when the SSM provisions apply. 
One commenter mostly supported the proposed amendment but stated that 
Sec.  63.2250(a) should not continue to differentiate between scheduled 
and unscheduled startups and shutdowns. In addition, the amendment does 
not resolve the confusion between scheduled and unscheduled startups 
and shutdowns. The commenter stated that although malfunctions can 
result in unscheduled startups and shutdowns, many unscheduled startups 
and shutdowns are considered to be normal operating practices by the 
industry rather than malfunctions. The proposed amendment fails to 
accurately clarify EPA's intent as stated in the preamble to the 
proposed amendments, and the proposed wording could inadvertently cause 
all unscheduled startups and shutdowns to be considered malfunctions. 
The commenter stated that the PCWP rule should not treat scheduled 
startups and shutdowns any differently from unscheduled startups and 
shutdowns.
    Another commenter stated that the SSM provisions are overly broad, 
and the proposed amendment suggests extending the provisions to 
unscheduled startups and shutdowns resulting from malfunction events. 
The commenter stated that EPA will only worsen the problems with the 
SSM provisions by promulgating this amendment, particularly in cases in 
which the equipment ``malfunction'' is not causally linked to any 
concurrent pollution exceedance.
    Response: We agree with the first commenter that the PCWP NESHAP 
should not differentiate between scheduled and unscheduled startups and 
shutdowns. The General Provisions do not treat scheduled startups and 
shutdowns any differently than unscheduled startups and shutdowns. 
Although it was not our intention to exclude unscheduled startups and 
shutdowns from Sec.  63.2250(b), we realize that the promulgated 
language did appear to exclude them, and our proposed amendment to this 
language did not clarify our intent. Therefore, we are removing all 
occurrences of ``scheduled'' and ``unscheduled'' from Sec.  63.2250(b). 
Sources should refer to Sec.  63.6(e) of the General Provisions for 
guidance on complying with the General Provisions during periods of 
SSM.

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), EPA 
must determine whether the regulatory action is ``significant'' and, 
therefore, subject to review by the Office of Management and Budget 
(OMB) and the requirements of the Executive Order. The Executive Order 
defines ``significant regulatory action'' as one that is likely to 
result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or tribal governments or 
communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs, or the rights and obligations of 
recipients thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    Pursuant to the terms of Executive Order 12866, it has been 
determined that today's action is a ``significant regulatory action'' 
because it raises novel legal or policy issues. As such, this action 
was submitted to OMB for review under Executive Order 12866. Changes 
made in response to OMB suggestions or recommendations are documented 
in the public record (see ADDRESSES section of this preamble).

B. Paperwork Reduction Act

    This action does not impose any new information collection burden. 
We are not promulgating any new paperwork (e.g., monitoring, reporting, 
recordkeeping) as part of today's final action. OMB has previously 
approved the information collection requirements contained in the final 
rule (40 CFR part 63, subpart DDDD) under the provisions of the 
Paperwork Reduction Act, 44 U.S.C. 3501, and has assigned OMB control 
number 2060-0552, EPA ICR number 1984.02. A copy of the OMB approved 
Information Collection Request (ICR) may be obtained from Susan Auby, 
Collection Strategies Division; U.S. Environmental Protection Agency 
(2822T); 1200 Pennsylvania Ave., NW., Washington, DC 20460 or by 
calling (202) 566-1672.
    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. This includes the time 
needed to review instructions; develop, acquire, install, and utilize 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    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 EPA's 
regulations are listed in 40 CFR part 9 and 48 CFR chapter 15.

C. Regulatory Flexibility Act

    The EPA has determined that it is not necessary to prepare a 
regulatory flexibility analysis in connection with this final action.
    For purposes of assessing the impacts of today's action on small 
entities, small entity is defined as: (1) A small business as defined 
by the Small Business Administrations' regulations at 13 CFR 121.201; 
(2) a small governmental jurisdiction that is a government of a city, 
county, town, school district or special district with a population of 
less than 50,000; and (3) a small organization that is any not-for-
profit enterprise which is independently owned and operated and is not 
dominant in its field.
    After considering the economic impacts of today's action on small 
entities, EPA has concluded that this action will not have a 
significant economic impact on a substantial number of small entities. 
In determining whether a rule has a significant economic impact on a 
substantial number of small entities, the impact of concern is any 
significant adverse economic impact on small entities, since the 
primary purpose of the regulatory flexibility analyses is to identify 
and address regulatory alternatives ``which minimize any significant 
economic impact of the proposed rule on small entities.'' 5 U.S.C. 
Sections 603 and 604. Thus, an agency may conclude that a rule will not 
have a significant economic impact on a substantial number of small 
entities if the rule relieves regulatory burden, or otherwise has a 
positive economic effect

[[Page 8370]]

on all of the small entities subject to the rule.
    Today's action reduces the number of emissions tests (and costs 
associated with these tests) required for facilities to demonstrate 
that they are part of the low-risk subcategory, and provides facilities 
with additional time to complete the tests and LRD. We have therefore 
concluded that today's final rule will relieve regulatory burden for 
all small entities.

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law 104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private sector. Under section 202 of the UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and final rules with ``Federal mandates'' that 
may result in expenditures by State, local, and tribal governments, in 
the aggregate, or by the private sector, of $100 million or more in any 
1 year. Before promulgating an EPA rule for which a written statement 
is needed, section 205 of the UMRA generally requires EPA to identify 
and consider a reasonable number of regulatory alternatives and adopt 
the least costly, most cost-effective, or least burdensome alternative 
that achieves the objectives of the rule. The provisions of section 205 
do not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows EPA to adopt an alternative other than the least 
costly, most cost-effective, or least burdensome alternative if the 
Administrator publishes with the final rule an explanation why that 
alternative was not adopted. Before EPA establishes any regulatory 
requirements that may significantly or uniquely affect small 
governments, including tribal governments, it must have developed, 
under section 203 of the UMRA, a small government agency plan. The plan 
must provide for notifying potentially affected small governments, 
enabling officials of affected small governments to have meaningful and 
timely input in the development of EPA's regulatory proposals with 
significant Federal intergovernmental mandates, and informing, 
educating, and advising small governments on compliance with the 
regulatory requirements.
    The EPA has determined that today's action does not contain a 
Federal mandate that may result in expenditures of $100 million or more 
for State, local, and tribal governments, in the aggregate, or the 
private sector in any 1 year. Although the final rule had annualized 
costs estimated to range from $74 to $140 million (depending on the 
number of facilities eventually demonstrating eligibility for the low-
risk category), today's action does not add new requirements that would 
increase this cost. Thus, today's action is not subject to the 
requirements of sections 202 and 205 of the UMRA. In addition, EPA has 
determined that today's action does not significantly or uniquely 
affect small governments because it contains no requirements that apply 
to such governments or impose obligations upon them. Therefore, today's 
action is not subject to the requirements of section 203 of the UMRA.

E. Executive Order 13132: Federalism

    Executive Order 13132 (64 FR 43255, August 10, 1999) requires EPA 
to develop an accountable process to ensure ``meaningful and timely 
input by State and local officials in the development of regulatory 
policies that have federalism implications.'' ``Policies that have 
federalism implications'' are defined in the Executive Order to include 
regulations that 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.'' Under Executive Order 13132, EPA may not issue a 
regulation that has federalism implications, that imposes substantial 
direct compliance costs, and that is not required by statute, unless 
the Federal government provides the funds necessary to pay the direct 
compliance costs incurred by State and local governments, or EPA 
consults with State and local officials early in the process of 
developing the proposed regulation. The EPA also may not issue a 
regulation that has federalism implications and that preempts State law 
unless EPA consults with State and local officials early in the process 
of developing the proposed regulation.
    If EPA complies by consulting, Executive Order 13132 requires EPA 
to provide to OMB, in a separately identified section of the preamble 
to the rule, a federalism summary impact statement (FSIS). The FSIS 
must include a description of the extent of EPA's prior consultation 
with State and local officials, a summary of the nature of their 
concerns and EPA's position supporting the need to issue the 
regulation, and a statement of the extent to which the concerns of 
State and local officials have been met. Also, when EPA transmits a 
draft final rule with federalism implications to OMB for review 
pursuant to Executive Order 12866, it must include a certification from 
EPA's Federalism Official stating that EPA has met the requirements of 
Executive Order 13132 in a meaningful and timely manner.
    Today's 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, 
as specified in Executive Order 13132. None of the affected facilities 
are owned or operated by State governments, and the requirements 
discussed in today's action will not supersede State regulations that 
are more stringent. Thus, Executive Order 13132 does not apply to 
today's action.

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

    Executive Order 13175 (65 FR 67249, November 6, 2000) requires EPA 
to develop an accountable process to ensure ``meaningful and timely 
input by tribal officials in the development of regulatory policies 
that have tribal implications.'' ``Policies that have tribal 
implications'' are defined in the Executive Order to include 
regulations that have ``substantial direct effects on one or more 
Indian tribes, on the relationship between the Federal government and 
the Indian tribes, or on the distribution of power and responsibilities 
between the Federal government and Indian tribes.''
    Today's action does not have tribal implications. It will not have 
substantial direct effects on tribal governments, on the relationship 
between the Federal government and Indian tribes, or on the 
distribution of power and responsibilities between the Federal 
government and Indian tribes, as specified in Executive Order 13175. No 
affected facilities are owned or operated by Indian tribal governments. 
Thus, Executive Order 13175 does not apply to today's action.

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

    Executive Order 13045 (62 FR 19885, April 23, 1997) applies to any 
rule that: (1) Is determined to be ``economically significant'' as 
defined under Executive Order 12866, and (2) concerns the environmental 
health or safety risk that EPA has reason to believe may have a 
disproportionate effect on children. If the regulatory action meets 
both criteria, EPA must evaluate the environmental

[[Page 8371]]

health or safety effects of the planned rule on children, and explain 
why the planned regulation is preferable to other potentially effective 
and reasonably feasible alternatives considered by EPA.
    Today's action is not subject to the Executive Order because it is 
not ``economically significant'' and EPA does not believe that the 
environmental health or safety risks associated with the emissions 
addressed by this action present a disproportionate risk to children. 
This conclusion is based on two factors. First, the noncancer human 
health toxicity values we used in our analysis at promulgation (e.g., 
RfCs) are protective of sensitive subpopulations, including children. 
Second, if EPA determines that a chemical addressed by this regulation 
has the potential for a disproportionate impact on predicted cancer 
risks due to early-life exposure and acts through a mutagenic mode of 
action, it is recommended that the risk assessments developed for the 
purposes of this regulation employ applicable cancer potency 
adjustments as described in EPA's Supplemental Guidance for Assessing 
Susceptibility from Early-Life Exposure to Carcinogens. For purposes of 
this rulemaking, EPA has not determined that any of the pollutants in 
question has the potential for a disproportionate impact on predicted 
cancer risks due to early-life exposure.

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

    Today's action is not a ``significant energy action'' as defined in 
Executive Order 13211 (66 FR 28355, May 22, 2001) because it is not 
likely to have a significant adverse effect on the supply, 
distribution, or use of energy. Further, we have concluded that today's 
action is not likely to have any adverse energy effects.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act (NTTAA) of 1995 (Pub. L. 104-113; 15 U.S.C. 272 note) directs EPA 
to use voluntary consensus standards in its regulatory and procurement 
activities unless to do so would be inconsistent with applicable law or 
otherwise impractical. Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, business practices) developed or adopted by one or more 
voluntary consensus bodies. The NTTAA directs EPA to provide Congress, 
through annual reports to OMB, with explanations when an agency does 
not use available and applicable voluntary consensus standards.
    This action involves two technical standards. In addition to the 
standards EPA included in the promulgated rule, the EPA cites the 
following standards in today's final amendments: (1) NCASI Method ISS/
FP-A105.01 (12/05), ``Impinger Source Sampling Method for Aldehydes, 
Ketones, And Polar Compounds''; and (2) EPA Method 207-A (proposed 12/
8/97 for appendix M to 40 CFR part 51), ``Method for Measuring 
Isocyanates in Stationary Source Emissions.''
    Consistent with the NTTAA, EPA conducted searches to identify 
voluntary consensus standards in addition to these methods. No 
applicable voluntary consensus standards were identified for EPA Method 
207-A. The search and review results have been documented and are 
placed in the docket for the final rule.
    One voluntary consensus standard was found that is potentially 
applicable to the NCASI method. The German standard VDI 3862 (12/00), 
``Gaseous Emission Measurement-Measurement of Aliphatic and Aromatic 
Aldehydes and Ketones by 2,4-Dinitrophenyhydrazine (DNPH) Impinger 
Method,'' is a good impinger method for the sampling and analysis of 
aldehydes and ketones that includes the use of an external standard, 
field and analytical blanks, and repeatability tests. However, the VDI 
method is missing some key quality assurance/quality control (QA/QC) 
procedures that are included in the NCASI method. Specifically, VDI 
3862 (12/00) is missing the use of internal standards, matrix spikes, 
and surrogate standards in the analytical step, as well as a duplicate 
sample run requirement, and sampling train QA/QC samples such as field, 
run, and sampling train spikes. Therefore, this VDI method, as written, 
is not acceptable as an alternative to the NCASI method for the 
purposes of today's rule amendments.
    Table 4 to subpart DDDD of 40 CFR part 63 and table 2B to appendix 
B to subpart DDDD of 40 CFR part 63 in today's rule amendments list the 
testing methods included in the final PCWP NESHAP. Under Sec. Sec.  
63.7(f) and 63.8(f) of subpart A of the General Provisions, a source 
may apply to EPA for permission to use alternative test methods or 
alternative monitoring requirements in place of any required testing 
methods, performance specifications, or procedures.

J. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. The EPA will submit a report containing this rule and 
other required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2). The final rule will be effective February 16, 2006.

List of Subjects for 40 CFR Part 63

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

    Dated: January 31, 2006.
Stephen L. Johnson,
Administrator.

0
For the reasons stated in the preamble, title 40, chapter I, part 63 of 
the Code of Federal Regulations is amended as follows:

PART 63--[AMENDED]

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

    Authority: 42 U.S.C. 7401.

Subpart A--[Amended]

0
2. Section 63.14 is amended by adding paragraph (f)(4) to read as 
follows:


Sec.  63.14  Incorporation by reference.

* * * * *
    (f) * * *
    (4) NCASI Method ISS/FP-A105.01, Impinger Source Sampling Method 
for Selected Aldehydes, Ketones, and Polar Compounds, December 2005, 
Methods Manual, NCASI, Research Triangle Park, NC, IBR approved for 
table 4 to subpart DDDD of this part and appendix B to subpart DDDD of 
this part.
* * * * *

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

0
3. Section 63.2232 is amended by revising paragraph (b) to read as 
follows:

[[Page 8372]]

Sec.  63.2232  What parts of my plant does this subpart cover?

* * * * *
    (b) The affected source is the collection of dryers, refiners, 
blenders, formers, presses, board coolers, and other process units 
associated with the manufacturing of plywood and composite wood 
products. 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 national emission standards for hazardous air 
pollutants (NESHAP)). The affected source also includes onsite storage 
and preparation of raw materials used in the manufacture of plywood 
and/or composite wood products, such as resins; onsite wastewater 
treatment operations specifically associated with plywood and composite 
wood products manufacturing; and miscellaneous coating operations 
(Sec.  63.2292). The affected source includes lumber kilns at PCWP 
manufacturing facilities and at any other kind of facility.
* * * * *

0
4. Section 63.2233 is amended by revising paragraphs (b) and (c) to 
read as follows:


Sec.  63.2233  When do I have to comply with this subpart?

* * * * *
    (b) If you have an existing affected source, you must comply with 
the compliance options, operating requirements, and work practice 
requirements for existing sources no later than October 1, 2008.
    (c) If you have an area source that increases its emissions or its 
potential to emit such that it becomes a major source of HAP, you must 
be in compliance with this subpart by October 1, 2008 or upon initial 
startup of your affected source as a major source, whichever is later.
* * * * *

0
5. Section 63.2250 is amended by revising paragraph (a) to read as 
follows:


Sec.  63.2250  What are the general requirements?

    (a) You must be in compliance with the compliance options, 
operating requirements, and the work practice requirements in this 
subpart at all times, except during periods of process unit or control 
device startup, shutdown, and malfunction; prior to process unit 
initial startup; and during the routine control device maintenance 
exemption specified in Sec.  63.2251. The compliance options, operating 
requirements, and work practice requirements do not apply during times 
when the process unit(s) subject to the compliance options, operating 
requirements, and work practice requirements are not operating, or 
during periods of startup, shutdown, and malfunction. Startup and 
shutdown periods must not exceed the minimum amount of time necessary 
for these events.
* * * * *

0
6. Section 63.2252 is added to read as follows:


Sec.  63.2252  What are the requirements for process units that have no 
control or work practice requirements?

    For process units not subject to the compliance options or work 
practice requirements specified in Sec.  63.2240 (including, but not 
limited to, lumber kilns), you are not required to comply with the 
compliance options, work practice requirements, performance testing, 
monitoring, SSM plans, and recordkeeping or reporting requirements of 
this subpart, or any other requirements in subpart A of this part, 
except for the initial notification requirements in Sec.  63.9(b).

0
7. Section 63.2262 is amended by revising paragraph (d)(1) to read as 
follows:


Sec.  63.2262  How do I conduct performance tests and establish 
operating requirements?

* * * * *
    (d) * * *
    (1) Sampling sites must be located at the inlet (if emission 
reduction testing or documentation of inlet methanol or formaldehyde 
concentration is required) and outlet of the control device (defined in 
Sec.  63.2292) and prior to any releases to the atmosphere. For control 
sequences with wet control devices (defined in Sec.  63.2292) followed 
by control devices (defined in Sec.  63.2292), sampling sites may be 
located at the inlet and outlet of the control sequence and prior to 
any releases to the atmosphere.
* * * * *

0
8. Section 63.2269 is amended by revising the introductory text of 
paragraph (c) to read as follows:


Sec.  63.2269  What are my monitoring installation, operation, and 
maintenance requirements?

* * * * *
    (c) Wood moisture monitoring. For each furnish or veneer moisture 
meter, you must meet the requirements in paragraphs (a)(1) through (3) 
and paragraphs (c)(1) through (5) of this section.
* * * * *

0
9. Section 63.2292 is amended by revising the definitions for 
``Affected source,'' ``Combustion unit,'' ``Fiberboard mat dryer,'' 
``Laminated veneer lumber,'' ``Lumber kiln,'' ``Plywood,'' ``Plywood 
and composite wood products manufacturing facility,'' ``Press 
predryer,'' ``Tube dryer,'' and ``Rotary strand dryer''; and adding 
definitions for ``Direct-fired process unit,'' ``Engineered wood 
product,'' ``Lumber,'' ``Molded particleboard,'' and ``Parallel strand 
lumber'' to read as follows:


Sec.  63.2292  What definitions apply to this subpart?

* * * * *
    Affected source means the collection of dryers, refiners, blenders, 
formers, presses, board coolers, and other process units associated 
with the manufacturing of plywood and composite wood products. 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 of raw materials used in the manufacture of plywood and/or 
composite wood products, such as resins; onsite wastewater treatment 
operations specifically associated with plywood and composite wood 
products manufacturing; and miscellaneous coating operations (defined 
elsewhere in this section). The affected source includes lumber kilns 
at PCWP manufacturing facilities and at any other kind of facility.
* * * * *
    Combustion unit means a dryer burner, process heater, or boiler. 
Combustion units may be used for combustion of organic HAP emissions.
* * * * *
    Direct-fired process unit means a process unit that is heated by 
the passing of combustion exhaust through the process unit such that 
the process material is contacted by the combustion exhaust.
* * * * *
    Engineered wood product means a product made with lumber, veneers,

[[Page 8373]]

strands of wood, or from other small wood elements that are bound 
together with resin. Engineered wood products include, but are not 
limited to, laminated strand lumber, laminated veneer lumber, parallel 
strand lumber, wood I-joists, and glue-laminated beams.
* * * * *
    Fiberboard mat dryer means a dryer used to reduce the moisture of 
wet-formed wood fiber mats by applying heat. A fiberboard mat dryer is 
a process unit.
* * * * *
    Laminated veneer lumber (LVL) means a composite product formed into 
a billet made from layers of resinated wood veneer sheets or pieces 
pressed together with the grain of each veneer aligned primarily along 
the length of the finished product. Laminated veneer lumber is also 
known as parallel strand lumber (PSL).
    Lumber means boards or planks sawed or split from logs or timber, 
including logs or timber processed for use as utility poles or other 
wood components. Lumber can be either green (non-dried) or dried. 
Lumber is typically either air-dried or kiln-dried.
    Lumber kiln means an enclosed dryer operated by applying heat to 
reduce the moisture content of lumber.
* * * * *
    Molded particleboard means a shaped composite product (other than a 
composite panel) composed primarily of cellulosic materials (usually 
wood or agricultural fiber) generally in the form of discrete pieces or 
particles, as distinguished from fibers, which are pressed together 
with resin.
* * * * *
    Parallel strand lumber (PSL) means a composite product formed into 
a billet made from layers of resinated wood veneer sheets or pieces 
pressed together with the grain of each veneer aligned primarily along 
the length of the finished product. Parallel strand lumber is also 
known as laminated veneer lumber (LVL).
* * * * *
    Plywood means a panel product consisting of layers of wood veneers 
hot pressed together with resin. Plywood includes panel products made 
by hot pressing (with resin) veneers to a substrate such as 
particleboard, medium density fiberboard, or lumber. Plywood products 
may be flat or curved.
    Plywood and composite wood products (PCWP) manufacturing facility 
means a facility that manufactures plywood and/or composite wood 
products by bonding wood material (fibers, particles, strands, veneers, 
etc.) or agricultural fiber, generally with resin under heat and 
pressure, to form a panel, engineered wood product, or other product 
defined in Sec.  63.2292. 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, molded particleboard, oriented strandboard, hardboard, 
fiberboard, medium density fiberboard, laminated strand lumber, 
laminated veneer lumber, wood I-joists, kiln-dried lumber, and glue-
laminated beams.
    Press predryer means a dryer used to reduce the moisture and 
elevate the temperature by applying heat to a wet-formed fiber mat 
before the mat enters a hot press. A press predryer is a process unit.
* * * * *
    Rotary strand dryer means a rotary dryer operated by applying heat 
and used to reduce the moisture of wood strands used in the manufacture 
of oriented strandboard, laminated strand lumber, or other wood strand-
based products. A rotary strand dryer is a process unit.
* * * * *
    Tube dryer means a single-stage or multi-stage dryer operated by 
applying heat to reduce the moisture of wood fibers or particles as 
they are conveyed (usually pneumatically) through the dryer. Resin may 
or may not be applied to the wood material before it enters the tube 
dryer. Tube dryers do not include pneumatic fiber transport systems 
that use temperature and humidity conditioned pneumatic system supply 
air in order to prevent cooling of the wood fiber as it is moved 
through the process. A tube dryer is a process unit.
* * * * *

0
10. Table 4 to subpart DDDD of part 63 is revised to read as follows:

 Table 4 to Subpart DDDD of Part 63.--Requirements for Performance Tests
------------------------------------------------------------------------
          For . . .              You must . . .          Using . . .
------------------------------------------------------------------------
(1) each process unit         select sampling       Method 1 or 1A of 40
 subject to a compliance       port's location and   CFR part 60,
 option in table 1A or 1B to   the number of         appendix A (as
 this subpart or used in       traverse ports.       appropriate).
 calculation of an emissions
 average under Sec.
 63.2240(c).
(2) each process unit         determine velocity    Method 2 in addition
 subject to a compliance       and volumetric flow   to Method 2A, 2C,
 option in table 1A or 1B to   rate.                 2D, 2F, or 2G in
 this subpart or used in                             appendix A to 40
 calculation of an emissions                         CFR part 60 (as
 average under Sec.                                  appropriate).
 63.2240(c).
(3) each process unit         conduct gas           Method 3, 3A, or 3B
 subject to a compliance       molecular weight      in appendix A to 40
 option in table 1A or 1B to   analysis.             CFR part 60 (as
 this subpart or used in                             appropriate).
 calculation of an emissions
 average under Sec.
 63.2240(c).
(4) each process unit         measure moisture      Method 4 in appendix
 subject to a compliance       content of the        A to 40 CFR part
 option in table 1A or 1B to   stack gas.            60; OR Method 320
 this subpart or used in                             in appendix A to 40
 calculation of an emissions                         CFR part 63; OR
 average under Sec.                                  ASTM D6348-03 (IBR,
 63.2240(c).                                         see Sec.
                                                     63.14(b)).
(5) each process unit         measure emissions of  Method 25A in
 subject to a compliance       total HAP as THC.     appendix A to 40
 option in table 1B to this                          CFR part 60. You
 subpart for which you                               may measure
 choose to demonstrate                               emissions of
 compliance using a total                            methane using EPA
 HAP as THC compliance                               Method 18 in
 option.                                             appendix A to 40
                                                     CFR part 60 and
                                                     subtract the
                                                     methane emissions
                                                     from the emissions
                                                     of total HAP as
                                                     THC.

[[Page 8374]]


(6) each process unit         measure emissions of  Method 320 in
 subject to a compliance       total HAP (as         appendix A to 40
 option in table 1A to this    defined in Sec.       CFR part 63; OR the
 subpart; OR for each          63.2292).             NCASI Method IM/CAN/
 process unit used in                                WP-99.02 (IBR, see
 calculation of an emissions                         Sec.   63.14(f));
 average under Sec.                                  OR the NCASI Method
 63.2240(c).                                         ISS/FP-A105.01
                                                     (IBR, see Sec.
                                                     63.14(f)); OR ASTM
                                                     D6348-03 (IBR, see
                                                     Sec.   63.14(b))
                                                     provided that
                                                     percent R as
                                                     determined in Annex
                                                     A5 of ASTM D6348-03
                                                     is equal or greater
                                                     than 70 percent and
                                                     less than or equal
                                                     to 130 percent.
(7) each process unit         measure emissions of  Method 308 in
 subject to a compliance       methanol.             appendix A to 40
 option in table 1B to this                          CFR part 63; OR
 subpart for which you                               Method 320 in
 choose to demonstrate                               appendix A to 40
 compliance using a methanol                         CFR part 63; OR the
 compliance option.                                  NCASI Method CI/WP-
                                                     98.01 (IBR, see
                                                     Sec.   63.14(f));
                                                     OR the NCASI Method
                                                     IM/CAN/WP-99.02
                                                     (IBR, see Sec.
                                                     63.14(f)); OR the
                                                     NCASI Method ISS/FP-
                                                     A105.01 (IBR, see
                                                     Sec.   63.14(f)).
(8) each process unit         measure emissions of  Method 316 in
 subject to a compliance       formaldehyde.         appendix A to 40
 option in table 1B to this                          CFR part 63; OR
 subpart for which you                               Method 320 in
 choose to demonstrate                               appendix A to 40
 compliance using a                                  CFR part 63; OR
 formaldehyde compliance                             Method 0011 in
 option.                                             ``Test Methods for
                                                     Evaluating Solid
                                                     Waste, Physical/
                                                     Chemical Methods''
                                                     (EPA Publication
                                                     No. SW-846) for
                                                     formaldehyde; OR
                                                     the NCASI Method CI/
                                                     WP-98.01 (IBR, see
                                                     Sec.   63.14(f));
                                                     OR the NCASI Method
                                                     IM/CAN/WP-99.02
                                                     (IBR, see Sec.
                                                     63.14(f)); OR the
                                                     NCASI Method ISS/FP-
                                                     A105.01 (IBR, see
                                                     Sec.   63.14(f)).
(9) each reconstituted wood   meet the design       Methods 204 and 204A
 product press at a new or     specifications        through 204F of 40
 existing affected source or   included in the       CFR part 51,
 reconstituted wood product    definition of wood    appendix M, to
 board cooler at a new         products enclosure    determine capture
 affected source subject to    in Sec.   63.2292;    efficiency (except
 a compliance option in        or                    for wood products
 table 1B to this subpart or  determine the          enclosures as
 used in calculation of an     percent capture       defined in Sec.
 emissions average under       efficiency of the     63.2292).
 Sec.   63.2240(c).            enclosure directing   Enclosures that
                               emissions to an add-  meet the definition
                               on control device.    of wood products
                                                     enclosure or that
                                                     meet Method 204
                                                     requirements for a
                                                     permanent total
                                                     enclosure (PTE) are
                                                     assumed to have a
                                                     capture efficiency
                                                     of 100 percent.
                                                     Enclosures that do
                                                     not meet either the
                                                     PTE requirements or
                                                     design criteria for
                                                     a wood products
                                                     enclosure must
                                                     determine the
                                                     capture efficiency
                                                     by constructing a
                                                     TTE according to
                                                     the requirements of
                                                     Method 204 and
                                                     applying Methods
                                                     204A through 204F
                                                     (as appropriate).
                                                     As an alternative
                                                     to Methods 204 and
                                                     204A through 204F,
                                                     you may use the
                                                     tracer gas method
                                                     contained in
                                                     appendix A to this
                                                     subpart.
(10) each reconstituted wood  determine the         a TTE and Methods
 product press at a new or     percent capture       204 and 204A
 existing affected source or   efficiency.           through 204F (as
 reconstituted wood product                          appropriate) of 40
 board cooler at a new                               CFR part 51,
 affected source subject to                          appendix M. As an
 a compliance option in                              alternative to
 table 1A to this subpart.                           installing a TTE
                                                     and using Methods
                                                     204 and 204A
                                                     through 204F, you
                                                     may use the tracer
                                                     gas method
                                                     contained in
                                                     appendix A to this
                                                     subpart. Enclosures
                                                     that meet the
                                                     design criteria (1)
                                                     through (4) in the
                                                     definition of wood
                                                     products enclosure,
                                                     or that meet Method
                                                     204 requirements
                                                     for a PTE (except
                                                     for the criteria
                                                     specified in
                                                     section 6.2 of
                                                     Method 204) are
                                                     assumed to have a
                                                     capture efficiency
                                                     of 100 percent.
                                                     Measured emissions
                                                     divided by the
                                                     capture efficiency
                                                     provides the
                                                     emission rate.
(11) each process unit        establish the site-   data from the
 subject to a compliance       specific operating    parameter
 option in tables 1A and 1B    requirements          monitoring system
 to this subpart or used in    (including the        or THC CEMS and the
 calculation of an emissions   parameter limits or   applicable
 average under Sec.            THC concentration     performance test
 63.2240(c).                   limits) in table 2    method(s).
                               to this subpart.
------------------------------------------------------------------------

?>
[[Page 8375]]

Appendix A to Subpart DDDD of Part 63--Alternative Procedure To 
Determine Capture Efficiency From Enclosures Around Hot Presses in the 
Plywood and Composite Wood Products Industry Using Sulfur Hexafluoride 
Tracer Gas

0
11. Revise paragraphs 10.4 and 10.5 of section 10 to read as follows:

    10.0 Calibration and Standardization.
* * * * *
    10.4 Gas Chromatograph. Follow the pre-test calibration 
requirements specified in section 8.5.1.
    10.5 Gas Chromatograph for Ambient Sampling (Optional). For the 
optional ambient sampling, follow the calibration requirements 
specified in section 8.5.1 or ASTM E 260 and E 697 and by the 
equipment manufacturer for gas chromatograph measurements.

* * * * *

0
12. Revise appendix B to subpart DDDD to read as follows:

Appendix B to Subpart DDDD of Part 63--Methodology and Criteria for 
Demonstrating That an Affected Source Is Part of the Low-risk 
Subcategory of Plywood and Composite Wood Products Manufacturing 
Affected Sources

1. Purpose

    This appendix provides the methodology and criteria for 
demonstrating that your affected source is part of the low-risk 
subcategory of plywood and composite wood products (PCWP) 
manufacturing facilities. You must demonstrate that your affected 
source is part of the low-risk subcategory using either a look-up 
table analysis (based on the look-up tables included in this 
appendix) or using a site-specific risk assessment performed 
according to the criteria specified in this appendix. This appendix 
also specifies how and when you must obtain approval of the low-risk 
demonstrations for your affected source and how to ensure that your 
affected source remains in the low-risk subcategory of PCWP 
facilities.

2. Who is eligible to demonstrate that they are part of the low-risk 
subcategory of PCWP affected sources?

    Each new, reconstructed, or existing affected source at a PCWP 
manufacturing facility may demonstrate that they are part of the 
low-risk subcategory of PCWP affected sources. Section 63.2232 of 40 
CFR part 63, subpart DDDD, defines the affected source and explains 
which affected sources are new, existing, or reconstructed.

3. What parts of my affected source have to be included in the low-risk 
demonstration?

    Every process unit that is part of the PCWP affected source (as 
defined in Sec.  63.2292 of 40 CFR part 63, subpart DDDD) and that 
emits one or more hazardous air pollutant (HAP) listed in table 1 to 
this appendix must be included in the low-risk demonstration. You 
are not required to include process units outside of the affected 
source in the low-risk demonstration.

4. What are the criteria for determining if my affected source is low 
risk?

    (a) Determine the individual HAP emission rates from each 
process unit emission point within the affected source using the 
procedures specified in section 5 of this appendix.
    (b) Perform chronic and acute risk assessments using the dose-
response values, as specified in paragraphs (b)(1) through (3) of 
this section.
    (1) For a look-up table analysis or site-specific chronic 
inhalation risk assessment, you should use the cancer and noncancer 
dose-response values listed on the Environmental Protection Agency 
(EPA) Air Toxics Web site (http://www.epa.gov/ttn/atw/toxsource/summary.html
) to estimate carcinogenic and noncarcinogenic chronic 

inhalation risk, respectively.
    (2) For site-specific acute inhalation risk assessment, you 
should use the acute exposure guidance level (AEGL-1) value for 
acrolein and the acute reference exposure level (REL) value for 
formaldehyde for estimating acute inhalation risk found at http://www.epa.gov/ttn/atw/toxsource/summary.html
.

    (3) You may use dose-response values more health-protective than 
those posted on the EPA Air Toxics Web site (http://www.epa.gov/ttn/atw/toxsource/summary.html
) to facilitate ongoing certification (as 

required in section 13 of this appendix) that your affected source 
remains in the low-risk subcategory.
    (c) Demonstrate that your affected source is part of the low-
risk subcategory by estimating the maximum impacts of your affected 
source using the methods described in either section 6 of this 
appendix (look-up table analysis) or section 7 of this appendix 
(site-specific risk assessment) and comparing the results to the 
low-risk criteria presented in the applicable section.

5. How do I determine HAP emissions from my affected source?

    (a) You must determine HAP emissions for every process unit 
emission point within the affected source that emits one or more of 
the HAP listed in table 1 to this appendix as specified in table 2A 
to this appendix. For each process unit type, table 2A to this 
appendix specifies whether emissions testing is required or if 
emissions estimation is allowed as an alternative to emissions 
testing. If emissions estimation is allowed according to table 2A, 
you must develop your emission estimates according to the 
requirements in paragraph (k) of this section. You may choose to 
perform emissions testing instead of emissions estimation. You must 
conduct HAP emissions tests according to the requirements in 
paragraphs (b) through (j) of this section and the methods specified 
in table 2B to this appendix. If you conduct fuel analyses, you must 
follow the requirements of paragraph (m) of this section. For each 
of the emission points at your affected source, you must obtain the 
emission rates in pounds per hour (lb/hr) for each of the pollutants 
listed in table 1 to this appendix.
    (b) Periods when emissions tests must be conducted.
    (1) You must not conduct emissions tests during periods of 
startup, shutdown, or malfunction, as specified in 40 CFR 
63.7(e)(1).
    (2) You must test under worst-case operating conditions as 
defined in this appendix. You must describe your worst-case 
operating conditions in your performance test report for the process 
and control systems (if applicable) and explain why the conditions 
are worst-case.
    (c) Number of test runs. You must conduct three separate test 
runs for each test required in this section, as specified in 40 CFR 
63.7(e)(3). Each test run must last at least 1 hour except for: 
testing of a temporary total enclosure (TTE) conducted using Methods 
204A through 204F in 40 CFR part 51, appendix M, which require three 
separate test runs of at least 3 hours each; and testing of an 
enclosure conducted using the alternative tracer gas method in 
appendix A to 40 CFR part 63, subpart DDDD, which requires a minimum 
of three separate runs of at least 20 minutes each.
    (d) Sampling locations. Sampling sites must be located at the 
emission point and prior to any releases to the atmosphere. For 
example, at the outlet of the control device, including wet control 
devices, and prior to any releases to the atmosphere.
    (e) Collection of monitoring data for HAP control devices. 
During the emissions test, you must collect operating parameter 
monitoring system or continuous emissions monitoring system (CEMS) 
data at least every 15 minutes during the entire emissions test and 
establish the site-specific operating requirements (including the 
parameter limits or total hydrocarbon (THC) concentration limit) in 
table 2 to 40 CFR part 63, subpart DDDD, using data from the 
monitoring system and the procedures specified in paragraphs (k) 
through (o) of Sec.  63.2262 of subpart DDDD of 40 CFR part 63.
    (f) Nondetect data. You may treat emissions of an individual HAP 
as zero if all of the test runs result in a nondetect measurement 
and the conditions in paragraphs (1) and (2) of this section are met 
for the relevant test method. Otherwise, nondetect data (as defined 
in Sec.  63.2292 of 40 CFR part 63, subpart DDDD) for individual HAP 
must be treated as one-half of the method detection limit.
    (1) The method detection limit is less than or equal to 1 part 
per million by volume, dry (ppmvd) for pollutant emissions measured 
using Method 320 in appendix A to 40 CFR part 63; or Method 18 in 
appendix A to 40 CFR part 60; or the NCASI Method IM/CAN/WP-99.02 
(incorporated by reference (IBR), see 40 CFR 63.14(f)); or NCASI 
Method ISS/FP-A105.01 (IBR, see 40 CFR 63.14(f); or ASTM D6348-03 
(IBR, see 40 CFR 63.14(b)).
    (2) For pollutants measured using Method 29 in appendix A to 40 
CFR part 60, you analyze samples using atomic absorption 
spectroscopy (AAS) or another laboratory method specified in Method 
29 in appendix A to 40 CFR part 60 with detection limits lower than 
or equal to AAS.
    (g) For purposes of your low-risk demonstration, you must assume 
that 17

[[Page 8376]]

percent of your total chromium measured using EPA Method 29 in 
appendix A to 40 CFR part 60 is chromium VI. You must assume that 65 
percent of your total nickel measured using EPA Method 29 in 
appendix A to 40 CFR part 60 is nickel subsulfide.
    (h) You may use emission rates higher than your measured 
emission rates (e.g., emissions rates 10 times your measured 
emission rate) to facilitate ongoing certification (as required in 
section 13 of this appendix) that your affected source remains in 
the low-risk subcategory.
    (i) Use of previous emissions tests. You may use the results of 
previous emissions tests provided that the following conditions are 
met:
    (1) The previous emissions tests must have been conducted using 
the methods specified in table 2B to this appendix. Previous 
emission test results obtained using NCASI Method IM/CAN/WP-99.01 
are acceptable.
    (2) The previous emissions tests must meet the requirements in 
paragraphs (b) through (j) of this section.
    (3) The subject process unit(s) must be operated in a manner 
(e.g., with raw material type, operating temperature, etc.) that 
would be expected to result in the same or lower emissions than 
observed during the previous emissions test(s) and the process 
unit(s) may not have been modified such that emissions would be 
expected to exceed (notwithstanding normal test-to-test variability) 
the results from previous emissions test(s).
    (4) The previous emissions test(s) must have been conducted in 
1997 or later.
    (j) Use of test data for similar process units. If you have 
multiple similar process units at the same plant site, you may apply 
the test results from one of these process units to the other 
similar process units for purposes of your low-risk demonstration 
provided that the following conditions are met:
    (1) You must explain how the process units are similar in terms 
of design, function, heating method, raw materials processed, 
residence time, change in material moisture content, operating 
temperature, resin type processed, age, and any other parameters 
that may affect emissions.
    (2) If the process units have different throughput rates, then 
you must convert the emission test results to terms of pounds of HAP 
per unit throughput prior to applying the emissions test data to 
other similar process units.
    (3) If one of the process units would be expected to exhibit 
higher emissions due to minor differences in process parameters, 
then you must explain and test the process unit that would be 
expected to exhibit greater emissions (for example, the unit with a 
slightly higher temperature set point, dryer processing furnish with 
slightly higher inlet moisture content, press processing thicker 
panels, unit with the greater throughput, considerably older unit, 
etc.).
    (k) If emissions estimation is allowed, you must follow the 
procedures in (1) through (3) of this paragraph.
    (1) You must use the emission factors or other emission 
estimation techniques specified in table 2A to this appendix when 
developing emission estimates.
    (2) You must base your emission estimates on the maximum process 
unit throughput you will incorporate into your permit according to 
section 11(b) of this appendix.
    (3) For process units with multiple emission points, you must 
apportion the estimate emissions evenly across each emission point. 
For example, if you have a process unit with two emission points, 
and the process unit is estimated to emit 6 lb/hr, you would assign 
3 lb/hr to each emission point.
    (l) Testing of multiple stacks. You may test one of multiple 
stacks for a process unit provided that the following conditions are 
met:
    (1) The emissions are produced by the same process unit.
    (2) The emissions originate from the same duct.
    (3) The emissions are sufficiently mixed so that the gaseous 
pollutant concentrations from one stack are not expected to differ 
from concentrations from another stack.
    (m) Conducting a fuel analysis. For process units that require 
testing of metals according to table 2A to this appendix, you may 
conduct a fuel analysis in lieu of emissions tests. You must follow 
the procedures described in Sec.  63.7521 (a) and (c) through (e) of 
subpart DDDDD; Sec.  63.7530(d)(1), (2), and (4) of subpart DDDDD, 
and line 2 of table 6 to subpart DDDDD. For purposes of this 
appendix, the total selected metals analyzed by fuel analysis are 
the metals included in table 1 to this appendix.

6. How do I conduct a look-up table analysis?

    Use the look-up tables (tables 3 and 4 to this appendix) to 
demonstrate that your affected source is part of the low-risk 
subcategory, following the procedures in paragraphs (a) through (d) 
of this section.
    (a) Using the emission rate of each HAP required to be included 
in your low-risk demonstration (determined according to section 5 of 
this appendix), calculate your total toxicity-weighted carcinogen 
and noncarcinogen emission rates for each of your emission points 
using Equations 1 and 2 of this appendix, respectively. Calculate 
your carcinogen and non-carcinogen weighted stack height using 
Equations 3 and 4 of this appendix, respectively.
[GRAPHIC] [TIFF OMITTED] TR16FE06.000

TWCER = Toxicity-weighted carcinogenic emission rate for each 
emission point (lb/hr)/([mu]g/m3)
ERi = Emission rate of pollutant i (lb/hr)
UREi = Unit risk estimate for pollutant i, 1 per 
microgram per cubic meter ([mu]g/m3)-1
[GRAPHIC] [TIFF OMITTED] TR16FE06.001

TWNER = Toxicity-weighted noncarcinogenic emission rate for each 
emission point (lb/hr)/([mu]g/m3)
ERi = Emission rate of pollutant i (lb/hr)
RfCi = Reference concentration for pollutant i, 
micrograms per cubic meter ([mu]g/m3)
[GRAPHIC] [TIFF OMITTED] TR16FE06.002

WHC = Carcinogen weighted stack height for use in the carcinogen 
look-up table (table 3 to this appendix)
H = Height of each individual stack or emission point (m)
ep = Individual stacks or emission points
n = Total number of stacks and emission points

[[Page 8377]]

[GRAPHIC] [TIFF OMITTED] TR16FE06.003

WHN = Non-carcinogen weighted stack height for use in the non-
carcinogen look-up table (table 4 to this appendix)
H = Height of each individual stack or emission point (m)
ep = Individual stacks or emission points
n = Total number of stacks and emission points

    (b) Cancer risk. Calculate the total toxicity-weighted 
carcinogen emission rate for your affected source by summing the 
toxicity-weighted carcinogen emission rates for each of your 
emission points. Identify the appropriate maximum allowable 
toxicity-weighted carcinogen emission rate from table 3 to this 
appendix for your affected source using the carcinogen weighted 
stack height of your emission points and the minimum distance 
between any emission point at the affected source and the property 
boundary. If one or both of these values do not match the exact 
values in the look-up table, then use the next lowest table value. 
(Note: If your weighted stack height is less than 5 meters (m), you 
must use the 5 m row.) Your affected source is considered low risk 
for carcinogenic effects if your toxicity-weighted carcinogen 
emission rate, determined using the methods specified in this 
appendix, does not exceed the values specified in table 3 to this 
appendix.
    (c) Noncancer risk. Calculate the total central nervous system 
(CNS) and respiratory target organ specific toxicity-weighted 
noncarcinogen emission rate for your affected source by summing the 
toxicity-weighted emission rates for each of your emission points. 
Identify the appropriate maximum allowable toxicity-weighted 
noncarcinogen emission rate from table 4 to this appendix for your 
affected source using the non-carcinogen weighted stack height of 
your emission points and the minimum distance between any emission 
point at the affected source and the property boundary. If one or 
both of these values do not match the exact values in the look-up 
table, then use the next lowest table value. (Note: If your weighted 
stack height is less than 5 m, you must use the 5 m row.) Your 
affected source is considered low risk for noncarcinogenic effects 
if your toxicity-weighted noncarcinogen emission rate, determined 
using the methods specified in this appendix, does not exceed the 
values specified in table 4 to this appendix.
    (d) Low-risk demonstration. The EPA will approve your affected 
source as eligible for membership in the low-risk subcategory of 
PCWP affected sources if it determines that: (1) Your affected 
source is low risk for both carcinogenic and noncarcinogenic effects 
using the look-up table analysis described in this section and (2) 
you meet the criteria specified in section 11 of this appendix.

7. How do I conduct a site-specific risk assessment?

    (a) Perform a site-specific risk assessment following the 
procedures specified in this section. You may use any 
scientifically-accepted peer-reviewed assessment methodology for 
your site-specific risk assessment. An example of one approach to 
performing a site-specific risk assessment for air toxics that may 
be appropriate for your affected source can be found in the ``Air 
Toxics Risk Assessment Guidance Reference Library, Volume 2, Site-
Specific Risk Assessment Technical Resource Document.'' You may 
obtain a copy of the ``Air Toxics Risk Assessment Reference 
Library'' through EPA's air toxics Web site at http://www.epa.gov/ttn/fera/risk_atra_main.html
.

    (b) At a minimum, your site-specific risk assessment must:
    (1) Estimate the long-term inhalation exposures through the 
estimation of annual or multi-year average ambient concentrations 
for the chronic portion of the assessment.
    (2) Estimate the acute exposures for formaldehyde and acrolein 
through the estimation of maximum 1-hour average ambient 
concentrations for the acute portion of the assessment.
    (3) Estimate the inhalation exposure of the individual most 
exposed to the affected source's emissions.
    (4) Estimate the individual risks over a 70-year lifetime for 
the chronic cancer risk assessment.
    (5) Use site-specific, quality-assured data wherever possible.
    (6) Use health-protective default assumptions wherever site-
specific data are not available.
    (7) Contain adequate documentation of the data and methods used 
for the assessment so that it is transparent and can be reproduced 
by an experienced risk assessor and emission measurement expert.
    (c) Your site-specific risk assessment need not:
    (1) Assume any attenuation of exposure concentrations due to the 
penetration of outdoor pollutants into indoor exposure areas.
    (2) Assume any reaction or deposition of the emitted pollutants 
during transport from the emission point to the point of exposure.
    (d) Your affected source is considered low risk for carcinogenic 
chronic inhalation effects if your site-specific risk assessment 
demonstrates that maximum off-site individual lifetime cancer risk 
at a location where people live or congregate (e.g., school or day 
care center) is less than 1 in 1 million.
    (e) Your affected source is considered low risk for 
noncarcinogenic chronic inhalation effects if your site-specific 
risk assessment demonstrates that every maximum off-site target-
organ specific hazard index (TOSHI), or appropriate set of site-
specific hazard indices based on similar or complementary mechanisms 
of action that are reasonably likely to be additive at low dose or 
dose-response data for mixtures, at a location where people live is 
less than or equal to 1.0.
    (f) Your affected source is considered low risk for 
noncarcinogenic acute inhalation effects if your site-specific risk 
assessment demonstrates that the maximum off-site acute hazard 
quotients for both acrolein and formaldehyde are less than or equal 
to 1.0.
    (g) The EPA will approve your affected source as eligible for 
membership in the low-risk subcategory of PCWP affected sources if 
it determines that: (1) your affected source is low risk for all of 
the applicable effects listed in paragraphs (d) through (f) of this 
section and (2) you meet the criteria specified in section 11 of 
this appendix.

8. What information must I submit for the low-risk demonstration?

    (a) Your low-risk demonstration must include at a minimum the 
information specified in paragraphs (a)(1) through (5) of this 
section and the information specified in either paragraph (b) or (c) 
of this section.
    (1) Identification of each process unit at the affected source.
    (2) Stack parameters for each emission point including, but not 
limited to, the parameters listed in paragraphs (a)(2)(i) through 
(iv) below:
    (i) Emission release type.
    (ii) Stack height, stack area, stack gas temperature, and stack 
gas exit velocity.
    (iii) Plot plan showing all emission points, nearby residences, 
and fenceline.
    (iv) Identification of any HAP control devices used to reduce 
emissions from each process unit.
    (3) Emission test reports for each pollutant and process unit 
based on the testing requirements and methods specified in tables 2A 
and 2B to this appendix, including a description of the process 
parameters identified as being worst case. You must submit your 
emissions calculations for each pollutant and process unit for which 
emissions estimates are developed. You must submit fuel analyses for 
each fuel and emission point which has been conducted, including 
collection and analytical methods used.
    (4) Identification of the dose-response values used in your risk 
analysis (look-up table analysis or site-specific risk assessment), 
according to section 4(b) of this appendix.
    (5) Identification of the controlling process factors 
(including, but not limited to, production rate, emission rate, type 
of control devices, process parameters documented as worst-case 
conditions during the emissions testing used for your low-risk 
demonstration) that will become Federally enforceable permit 
conditions used to show

[[Page 8378]]

that your affected source remains in the low-risk subcategory.
    (b) If you use the look-up table analysis in section 6 of this 
appendix to demonstrate that your affected source is low risk, your 
low-risk demonstration must contain at a minimum the information in 
paragraphs (a) and (b)(1) through (4) of this section.
    (1) Identification of the stack heights for each emission point 
included in the calculations of weighted stack height.
    (2) Identification of the emission point with the minimum 
distance to the property boundary.
    (3) Calculations used to determine the toxicity-weighted 
carcinogen and noncarcinogen emission rates and weighted stack 
heights according to section 6(a) of this appendix.
    (4) Comparison of the values in the look-up tables (tables 3 and 
4 to this appendix) to your toxicity-weighted emission rates for 
carcinogenic and noncarcinogenic HAP.
    (c) If you use a site-specific risk assessment as described in 
section 7 of this appendix to demonstrate that your affected source 
is low risk (for carcinogenic and noncarcinogenic chronic inhalation 
and acute inhalation risks), your low-risk demonstration must 
contain at a minimum the information in paragraphs (a) and (c)(1) 
through (8) of this section.
    (1) Identification of the risk assessment methodology used.
    (2) Documentation of the fate and transport model used.
    (3) Documentation of the fate and transport model inputs, 
including the information described in paragraphs (a)(1) through (4) 
of this section converted to the dimensions required for the model 
and all of the following that apply: meteorological data; building, 
land use, and terrain data; receptor locations and population data; 
and other facility-specific parameters input into the model.
    (4) Documentation of the fate and transport model outputs.
    (5) Documentation of exposure assessment and risk 
characterization calculations.
    (6) Comparison of the maximum off-site individual lifetime 
cancer risk at a location where people live to 1 in 1 million, as 
required in section 7(d) of this appendix for carcinogenic chronic 
inhalation risk.
    (7) Comparison of the maximum off-site TOSHI for respiratory 
effects and CNS effects at a location where people live to the limit 
of 1.0, as required in section 7(e) of this appendix for 
noncarcinogenic chronic inhalation risk.
    (8) Comparison of the maximum off-site acute inhalation hazard 
quotient (HQ) for both acrolein and formaldehyde to the limit of 
1.0, as required in section 7(f) of this appendix for 
noncancinogenic acute inhalation effects.
    (d) The EPA may request any additional information it determines 
is necessary or appropriate to evaluate an affected source's low-
risk demonstration.

9. Where do I send my low-risk demonstration?

    You must submit your low-risk demonstration to the EPA for 
review and approval. Send your low-risk demonstration either by e-
mail to REAG@EPA.GOV or by U.S. mail or other mail delivery service 
to U.S. EPA, Risk and Exposure Assessment Group, Emission Standards 
Division (C404-01), Attn: Group Leader, Research Triangle Park, NC 
27711, and send a copy to your permitting authority. Your affected 
source is not part of the low-risk subcategory of PCWP facilities 
unless and until EPA notifies you that it has determined that you 
meet the requirements of section 11 of this appendix.

10. When do I submit my low-risk demonstration?

    (a) Existing affected sources. If you have an existing affected 
source, you may complete and submit for approval your low-risk 
demonstration (including the emission test results, fuel analyses, 
and emission estimates required in this appendix) any time. Existing 
affected sources that are not approved by EPA as being part of the 
low-risk subcategory by October 1, 2008, must comply with the 
requirements of 40 CFR part 63, subpart DDDD from October 1, 2008, 
unless and until EPA approves them as part of the low-risk 
subcategory.
    (b) Sources in compliance with 40 CFR part 63, subpart DDDD. If 
you operate an affected source that is already in compliance with 40 
CFR part 63, subpart DDDD (including, but not limited to, an 
existing source, a new or reconstructed affected source starting up 
before September 28, 2004, or a new source starting up after 
September 28, 2004, but before February 16, 2006) and wish to become 
part of the low-risk subcategory, then you may complete and submit 
for approval your low-risk demonstration (including the emission 
test results, fuel analyses, and emission estimates required in this 
appendix) any time. Your affected source will become part of the 
low-risk subcategory when EPA determines that the requirements in 
section 11 of this appendix are met.
    (c) New or reconstructed affected sources wanting to be part of 
the low-risk subcategory at startup must comply with the 
requirements of paragraphs (c)(1) through (c)(3) of this section.
    (1)(i) You must complete and submit for review and approval a 
pre-startup low-risk demonstration no later than nine months prior 
to initial startup. The pre-startup low-risk demonstration must be 
based on the information (e.g., equipment types, estimated emission 
rates, etc.) that you will likely use to obtain your title V permit. 
You must base your pre-startup low-risk demonstration on the maximum 
emissions that will likely be allowed when you obtain your title V 
permit.
    (ii) You must request that your affected source become part of 
the low-risk subcategory based on your pre-startup low-risk 
demonstration.
    (iii) If EPA approves your pre-startup low-risk demonstration, 
then your affected source will be part of the low-risk subcategory 
upon approval of the pre-startup low-risk demonstration and you may 
start up your affected source without complying with the compliance 
options, operating requirements, and work practice requirements in 
40 CFR part 63, subpart DDDD, provided that you operate your 
affected source consistently with the pre-startup low-risk 
demonstration until you meet the criteria in section 11 of this 
appendix based on your verification low-risk demonstration developed 
according to paragraph (c)(2) of this section. Failure to so operate 
will render approval of your pre-startup low-risk demonstration null 
and void from the date you startup your affected source.
    (2)(i) You must complete and submit your verification low-risk 
demonstration, including the results from emission tests (or fuel 
analyses) required in this appendix, within 240 days following 
initial startup. The verification low-risk demonstration must 
demonstrate to EPA's satisfaction that the affected source is low 
risk. The verification low-risk demonstration may be used to change 
operating parameters ensuring low-risk status.
    (ii) If you do not submit the verification low-risk 
demonstration as required, or the verification low-risk 
demonstration does not verify that the affected source is low risk, 
then approval of your pre-startup low-risk demonstration is null and 
void from the date you startup your affected source and you must 
comply immediately with subpart DDDD of 40 CFR part 63.
    (3) To incorporate the low-risk parameters from your 
verification low-risk demonstration into your title V permit, you 
must submit your application for a significant modification to your 
title V permit within 1 year following initial startup, or earlier 
if so required under your State's permit program approved under 40 
CFR part 70. The parameters that defined your affected source as 
part of the low-risk subcategory (including, but not limited to, 
production rate, emission rate, type of control devices, process 
parameters reflecting the emissions rates used for your low-risk 
demonstration, and stack height) must be submitted for incorporation 
as federally enforceable terms and conditions into your title V 
permit. You must provide written certification to the permitting 
authority that your affected source is operating consistently with 
its EPA-approved pre-startup low-risk demonstration and verification 
low-risk demonstration, as applicable, from startup until your title 
V permit revision is issued.
    (d) New or reconstructed affected sources that want to operate 
consistently with a pre-startup low-risk demonstration at startup 
and become part of the low-risk subcategory based on EPA approval of 
their verification low-risk demonstration (rather than based on 
their pre-startup low-risk demonstration), must comply with the 
requirements in paragraphs (d)(1) through (d)(3) of this section.
    (1)(i) You must complete and submit for review a pre-startup 
low-risk demonstration no later than nine months prior to initial 
startup. The pre-startup low-risk demonstration must be based on the 
information (e.g., equipment types, estimated emission rates, etc.) 
that you will likely use to obtain your title V permit. You must 
base your pre-startup low-risk demonstration on the maximum 
emissions that will likely be allowed when you obtain your title V 
permit.
    (ii) If EPA concludes that your pre-startup low-risk 
demonstration is complete and

[[Page 8379]]

sufficiently shows that your affected source appears to be eligible 
for inclusion in the low-risk subcategory, then you must operate 
your affected source consistently with the pre-startup low-risk 
demonstration until EPA determines that you meet the criteria in 
section 11 of this appendix based on your verification low-risk 
demonstration developed according to paragraph (d)(2) of this 
section.
    (2)(i) You must complete and submit for EPA review and approval 
your verification low-risk demonstration, including the results from 
emission tests (or fuel analyses) required in this appendix, within 
240 days following initial startup. The verification low-risk 
demonstration must demonstrate to EPA's satisfaction that the 
affected source is low risk.
    (ii) You will become part of the low-risk subcategory when EPA 
determines that you meet the criteria in section 11 of this appendix 
based upon your verification low-risk demonstration. If you do not 
submit the verification low-risk demonstration as required, or the 
verification low-risk demonstration does not verify that the 
affected source is low risk, then EPA will not approve your low-risk 
demonstration and you will remain subject to subpart DDDD of 40 CFR 
part 63.
    (3) To incorporate the low-risk parameters from your 
verification low-risk demonstration into your title V permit, you 
must submit your application for a significant modification to your 
title V permit within 1 year following initial startup, or earlier 
if so required by your State's permit program approved by EPA under 
40 CFR part 70. The parameters that defined your affected source as 
part of the low-risk subcategory (including, but not limited to, 
production rate, emission rate, type of control devices, process 
parameters reflecting the emissions rates used for your low-risk 
demonstration, and stack height) must be submitted for incorporation 
as federally enforceable terms and conditions into your title V 
permit. You must provide written certification to the permitting 
authority that your affected source is operating consistently with 
its pre-startup LRD and your verification LRD, as applicable, from 
startup until your title V permit revision is issued.
    (e) Area sources that become affected sources. If you have an 
affected source that is an area source that increases its emissions 
or its potential to emit such that it becomes a major source of HAP 
before September 28, 2004, then you must complete and submit for 
approval your low-risk demonstration as specified in paragraph (a) 
of this section. If you have an affected source that is an area 
source that increases its emissions or its potential to emit such 
that it becomes a major source of HAP after September 28, 2004, then 
you must complete and submit for approval your low-risk 
demonstration as specified in paragraphs (b), (c) or (d) of this 
section, whichever applies.

11. How does my affected source become part of the low-risk subcategory 
of PCWP facilities?

    For existing sources to be included in the low-risk subcategory, 
EPA must find that you meet the criteria in paragraphs (a) and (b) 
of this section. For new sources to be included in the low-risk 
subcategory, EPA must find that you meet the criteria in paragraph 
(a) of this section. Unless and until EPA finds that you meet these 
criteria, your affected source is subject to the applicable 
compliance options, operating requirements, and work practice 
requirements in 40 CFR part 63, subpart DDDD.
    (a) Your demonstration of low risk must be approved by EPA.
    (b) Following EPA approval, the parameters that defined your 
affected source as part of the low-risk subcategory (including, but 
not limited to, production rate, emission rate, type of control 
devices, process parameters reflecting the emissions rates used for 
your low-risk demonstration, and stack height) must be submitted for 
incorporation as federally enforceable terms and conditions into 
your title V permit. You must submit an application for a 
significant permit modification to reopen your title V permit to 
incorporate such terms and conditions according to the procedures 
and schedules of 40 CFR part 71 or the EPA-approved program in 
effect under 40 CFR part 70, as applicable.

12. What must I do to ensure my affected source remains in the low-risk 
subcategory of PCWP facilities?

    You must meet the requirements in table 2 to 40 CFR part 63, 
subpart DDDD, for each HAP control device used at the time when you 
completed your low-risk demonstration. You must monitor and collect 
data according to Sec.  63.2270 of subpart DDDD to show continuous 
compliance with your control device operating requirements. You must 
demonstrate continuous compliance with the control device operating 
requirements that apply to you by collecting and recording the 
monitoring system data listed in table 2 to 40 CFR part 63, subpart 
DDDD for the process unit according to Sec. Sec.  63.2269(a), (b), 
and (d) of subpart DDDD; and reducing the monitoring system data to 
the specified averages in units of the applicable requirement 
according to calculations in Sec.  63.2270 of subpart DDDD; and 
maintaining the average operating parameter at or above the minimum, 
at or below the maximum, or within the range (whichever applies) 
established according to section 5(e) of this appendix.

13. What happens if the criteria used in the risk determination change?

    (a) You must certify with each annual title V permit compliance 
certification that the basis for your affected source's low-risk 
determination has not changed. You must submit this certification to 
the permitting authority. You must consider the changes in 
paragraphs (a)(1) through (5) of this section.
    (1) Process changes that increase HAP emissions, including, but 
not limited to, a production rate increase, an emission rate 
increase, a change in type of control device, changes in process 
parameters reflecting emissions rates used for your approved low-
risk demonstration.
    (2) Population shifts, such as if people move to a different 
location such that their risks from the affected source increase.
    (3) Unit risk estimate increases posted on the EPA Web site 
(http://www.epa.gov/ttn/atw/toxsource/summary.html) for the 

pollutants included in table 1 to this appendix.
    (4) Reference concentration changes posted on the EPA Web site 
(http://www.epa.gov/ttn/atw/toxsource/summary.html) for the 

pollutants included in table 1 to this appendix.
    (5) Acute dose-response value for formaldehyde or acrolein 
changes.
    (b) If your affected source commences operating outside of the 
low-risk subcategory, it is no longer part of the low-risk 
subcategory. You must be in compliance with 40 CFR part 63, subpart 
DDDD as specified in paragraphs (b)(1) through (3) of this section. 
Operating outside of the low-risk subcategory means that one of the 
changes listed in paragraphs (a)(1) through (5) of this section has 
occurred and that the change is inconsistent with your affected 
source's title V permit terms and conditions reflecting EPA's 
approval of the parameters used in your low-risk demonstration.
    (1) You must notify the permitting authority as soon as you 
know, or could have reasonably known, that your affected source is 
or will be operating outside of the low-risk subcategory.
    (2) You must be in compliance with the requirements of 40 CFR 
part 63, subpart DDDD as specified in paragraph (b)(2)(i) or (ii) of 
this section, whichever applies.
    (i) If you are operating outside of the low-risk subcategory due 
to a change described in paragraph (a)(1) of this section, then you 
must comply with 40 CFR part 63, subpart DDDD beginning on the date 
when your affected source commences operating outside the low-risk 
subcategory.
    (ii) If you are operating outside of the low-risk subcategory 
due to a change described in paragraphs (a)(2) through (5) of this 
section, then you must comply with 40 CFR part 63, subpart DDDD no 
later than 3 years from the date your affected source commences 
operating outside the low-risk subcategory.
    (3)(i) You must conduct performance tests no later than 180 
calendar days after the applicable date specified in paragraph 
(b)(2) of this section.
    (ii) You must conduct initial compliance demonstrations that do 
not require performance tests 30 calendar days after the applicable 
date specified in paragraph (b)(2) of this section.
    (iii) For the purposes of affected sources affected by this 
section, you must refer to the requirements in paragraph (b) of this 
section instead of the requirements of Sec.  63.2233 when complying 
with 40 CFR part 63, subpart DDDD.

14. What records must I keep?

    (a) You must keep records of the information used in developing 
the low-risk demonstration for your affected source, including all 
of the information specified in section 8 of this appendix.
    (b) You must keep records demonstrating continuous compliance 
with the operating requirements for control devices.
    (c) For each THC CEMS, you must keep the records specified in 
Sec.  63.2282(c) of 40 CFR part 63, subpart DDDD.

[[Page 8380]]

15. Definitions

    The definitions in Sec.  63.2292 of 40 CFR part 63, subpart 
DDDD, apply to this appendix. Additional definitions applicable for 
this appendix are as follows:
    Agricultural fiber board press means a press used in the 
production of an agricultural fiber based composite wood product. An 
agricultural fiber board press is a process unit.
    Agricultural fiberboard mat dryer means a dryer used to reduce 
the moisture of wet-formed agricultural fiber mats by applying heat. 
An agricultural fiberboard mat dryer is a process unit.
    Ancillary processes mean equipment and process units that are 
part of the PCWP affected source that are not defined elsewhere in 
this section or in section 63.2292 of subpart DDDD. Ancillary 
processes at a specific facility do not include the equipment and 
process units identified as insignificant sources of HAP emissions 
by that facility, and they do not include equipment and process 
units subject to another standard under 40 CFR part 63. Ancillary 
processes may be or may not be HAP emissions sources.
    Ancillary processes are process units.
    Atmospheric refiner means a piece of equipment operated under 
atmospheric pressure for refining (rubbing or grinding) the wood 
material into fibers or particles. Atmospheric refiners are operated 
with continuous infeed and outfeed of wood material and atmospheric 
pressures throughout the refining process. An atmospheric refiner is 
a process unit.
    Blending and forming operations means the process of mixing 
adhesive and other additives with the (wood) furnish of the 
composite panel and making a mat of resinated fiber, particles, or 
strands to be compressed into a reconstituted wood product such as 
particleboard, oriented strandboard, or medium density fiberboard. 
Blending and forming operations are process units.
    Emission point means an individual stack or vent from a process 
unit that emits HAP required for inclusion in the low-risk 
demonstration specified in this appendix. Process units may have 
multiple emission points.
    Fiber washer means a unit in which water-soluble components of 
wood (hemicellulose and sugars) that have been produced during 
digesting and refining are removed from the wood fiber. Typically 
wet fiber leaving a refiner is further diluted with water and then 
passed over a filter, leaving the cleaned fiber on the surface. A 
fiber washer is a process unit.
    Finishing sander means a piece of equipment that uses an 
abrasive drum, belt, or pad to impart smoothness to the surface of a 
plywood or composite wood product panel and to reduce the panel to 
the prescribed thickness. A finishing sander is a process unit.
    Finishing saw means a piece of equipment used to trim or cut 
finished plywood and composite wood products panels to a certain 
size. A finishing saw is a process unit.
    Hardwood plywood press means a hot press which, through heat and 
pressure, bonds assembled hardwood veneers (including multiple plies 
of veneer and/or a substrate) and resin into a hardwood plywood 
panel. A hardwood plywood press is a process unit.
    Hardwood veneer kiln means an enclosed dryer operated in batch 
cycles by applying heat to reduce the moisture content from stacked 
hardwood veneer. A hardwood veneer kiln is a process unit.
    Hazard Index (HI) means the sum of more than one hazard quotient 
for multiple substances and/or multiple exposure pathways.
    Hazard Quotient (HQ) means the ratio of the predicted media 
concentration of a pollutant to the media concentration at which no 
adverse effects are expected. For inhalation exposures, the HQ is 
calculated as the air concentration divided by the reference 
concentration (RfC).
    Humidifier means a process unit used to increase the moisture 
content of hardboard following pressing or after post-baking. 
Typically, water vapor saturated air is blown over the hardboard 
surfaces in a closed cabinet. A humidifier is a process unit.
    I-joist curing chamber means an oven or a room surrounded by a 
solid wall or heavy plastic flaps that uses heat, infrared, or 
radio-frequency techniques to cure the adhesive. An I-joist curing 
chamber is a process unit.
    Log chipping means the production of wood chips from logs.
    Log vat means a process unit that raises the temperature of the 
logs inside by applying a heated substance, usually hot water and 
steam, to the outside of the logs by spraying or soaking. A log vat 
is a process unit.
    Look-up table analysis means a risk screening analysis based on 
comparing the toxicity-weighted HAP emission rate from the affected 
source to the maximum allowable toxicity-weighted HAP emission rates 
specified in tables 3 and 4 to this appendix.
    LSL press means a composite wood product press that presses a 
loose mat of resinated strands into a billet by simultaneous 
application of heat and pressure. The billet is cut into laminated 
strand lumber after exiting the press. An LSL press is a process 
unit.
    LVL or PSL press means a composite wood product press that 
presses resinated stacks of veneers into a solid billet by 
application of heat and/or pressure. The billet is cut into 
laminated veneer lumber or parallel strand lumber after exiting the 
press. An LVL or PSL press is a process unit.
    Natural gas means a naturally occurring mixture of hydrocarbon 
and non-hydrocarbon gases found in geologic formations beneath the 
earth's surface. The principal hydrocarbon constituent is methane.
    Paddle-type particleboard dryer means a dryer to which heat is 
applied to remove moisture from particles and paddles to advance 
materials through the dryer. This type of dryer removes moisture 
absorbed by particles due to high ambient temperature. A paddle-type 
particleboard dryer is a process unit.
    Panel-trim chipper means a piece of equipment that accepts the 
discarded pieces of veneer or pressed plywood and composite wood 
products panels that are removed by finishing saws and reduces these 
pieces to small elements. A panel-trim chipper is a process unit.
    Particleboard extruder means a heated die oriented either 
horizontally or vertically through which resinated particles are 
continuously forced to form extruded particleboard products. A 
particleboard extruder is a process unit.
    Particleboard press mold means a press that consists of molds 
that apply heat and pressure to form molded or shaped particleboard 
products. A particleboard press mold is a process unit.
    Propane means a colorless gas derived from petroleum and natural 
gas, with the molecular structure C3H8.
    Radio-frequency veneer redryer means a dryer heated by radio-
frequency waves that is used to redry veneer that has been 
previously dried. A radio-frequency veneer redryer is a process 
unit.
    Reference Concentration (RfC) means an estimate (with 
uncertainty spanning perhaps an order of magnitude) of a continuous 
inhalation exposure to the human population (including sensitive 
subgroups) that is likely to be without an appreciable risk of 
deleterious effects during a lifetime. It can be derived from 
various types of human or animal data, with uncertainty factors 
generally applied to reflect limitations of the data used.
    Resin storage tank means any storage tank, container, or vessel 
connected to plywood and composite wood product production that 
holds resin additives (in liquid form) containing any of the HAP 
listed in table 2A to this appendix. A resin storage tank is a 
process unit.
    Rotary agricultural fiber dryer means a rotary dryer operated by 
applying heat to reduce the moisture of agricultural fiber. A rotary 
agricultural fiber dryer is a process unit.
    Softwood plywood press means a hot press which, through heat and 
pressure, bonds assembled softwood veneer plies and resin into a 
softwood plywood panel. A softwood plywood press is a process unit.
    Softwood veneer kiln means an enclosed dryer operated in batch 
cycles by applying heat to reduce the moisture content from stacked 
softwood veneer. A softwood veneer kiln is a process unit.
    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. A stand-alone 
digester is a process unit.
    Target organ specific hazard index (TOSHI) means the sum of 
hazard quotients for individual chemicals that affect the same organ 
or organ system (e.g., respiratory system, central nervous system).
    Unit Risk Estimate (URE) means the upper-bound excess lifetime 
cancer risk estimated to result from continuous exposure to an agent 
at a concentration of 1 microgram per cubic meter ([mu]g/
m3) in air.
    Wastewater/process water operation means equipment that 
processes water in plywood or composite wood product facilities for

[[Page 8381]]

reuse or disposal. Wastewater/process water operations includes but 
is not limited to pumps, holding ponds and tanks, cooling and 
heating operations, settling systems, filtration systems, aeration 
systems, clarifiers, pH adjustment systems, log storage ponds, 
pollution control device water (including wash water), vacuum 
distillation systems, sludge drying and disposal systems, spray 
irrigation fields, and connections to POTW facilities. Wastewater/
process water operations are process units.
    Worst-case operating conditions means operation of a process 
unit during emissions testing under the conditions that result in 
the highest HAP emissions or that result in the emissions stream 
composition (including HAP and non-HAP) that is most challenging for 
the control device if a control device is used. For example, worst 
case conditions could include operation of the process unit at 
maximum throughput, at its highest temperature, with the wood 
species mix likely to produce the most HAP, and/or with the resin 
formulation containing the greatest HAP.

 Table 1 to Appendix B to Subpart DDDD of 40 CFR Part 63.--HAP That Must
  Be Included in the Demonstration of Eligibility for the Low-risk PCWP
                               Subcategory
------------------------------------------------------------------------
   For your analysis of the following     You must include the following
             effects . . .                          HAP . . .
------------------------------------------------------------------------
(1) Chronic inhalation carcinogenic      acetaldehyde, benzene, arsenic,
 effects.                                 beryllium, cadmium, chromium,
                                          lead, nickel, and
                                          formaldehyde.
(2) Chronic inhalation noncarcinogenic   acetaldehyde, acrolein,
 respiratory effects.                     cadmium, formaldehyde, and
                                          methylene diphenyl
                                          diisocyanate (MDI).
(3) Chronic inhalation noncarcinogenic   manganese, lead, and phenol.
 CNS effects.
(4) Acute inhalation...................  acrolein and formaldehyde.
------------------------------------------------------------------------


                                  Table 2A to Appendix B to Subpart DDDD of 40 CFR Part 63.--Testing and Emissions Estimation Specifications for Process Units
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                                               HAP metals from
        Process unit type               Acetaldehyde             Acrolein             Formaldehyde              Phenol                Benzene                  MDI          direct-fired process
                                                                                                                                                                                  units \a\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Agricultural fiberboard mat        Test.................  Test.................  Test.................  Test.................  Test.................  NA..................  Test or fuel
 dryers, Dry rotary dryers,                                                                                                                                                  analysis.
 Fiberboard mat dryer (heated
 zones), Green rotary dryers,
 Hardboard ovens, Hardwood veneer
 dryers (heated zones), Paddle-
 type particleboard dryers, Press
 predryers, Rotary agricultural
 fiber dryers, Rotary strand
 dryers, Softwood veneer dryers
 (heated zones), Veneer redryers
 (heated by conventional means).
Atmospheric refiners, Conveyor     Test.................  Test.................  Test.................  Test.................  Test.................  NA..................  NA.
 strand dryers, Pressurized
 refiners.
Primary tube dryers, Secondary     Test.................  Test.................  Test.................  Test.................  Test.................  Test if processing    Test or fuel
 tube dryers.                                                                                                                                          furnish with MDI      analysis.
                                                                                                                                                       resin added prior
                                                                                                                                                       to drying.
Agricultural fiber board presses,  Test.................  Test.................  Test.................  Test.................  Test.................  Test if board         NA
 Reconstituted wood products                                                                                                                           contains MDI resin.
 presses, Reconstituted wood
 product board coolers.
Blending and forming operations--  NA...................  NA...................  0.060 lb/ODT\b\......  NA...................  NA...................  Engineering estimate  NA.
 particleboard and MDF.                                                                                                                                if MDI resin used.
Blending and forming operations--  NA...................  NA...................  0.0036 lb/MSF \3/8\''  Engineering estimate.  NA...................  Engineering estimate  NA.
 OSB.                                                                             press throughput.                                                    if MDI resin used.
Dry forming--hardboard...........  Engineering estimate.  NA...................  Engineering estimate.  Engineering estimate.  NA...................  NA..................  NA.
Fiber washers....................  0.015 lb/ODT.........  NA...................  0.0026 lb/ODT........  NA...................  NA...................  NA..................  NA.
Fiberboard mat dryer (fugitive     0.0055 lb/MSF \1/2\''  NA...................  0.031 lb/MSF \1/2\''.  NA...................  NA...................  NA..................  NA.
 emissions).

[[Page 8382]]


Finishing sanders................  0.0031 lb/MSF........  NA...................  0.0042 lb/MSF........  0.015 lb/MSF.........  NA...................  Engineering estimate  NA.
                                                                                                                                                       if MDI resin used.
Finishing saws...................  0.00092 lb/MSF \3/     NA...................  0.00034 lb/MSF \3/     0.0057 lb/MSF........  NA...................  Engineering estimate  NA.
                                    8\''.                                         8\''.                                                                if MDI resin used.
Hardwood plywood presses.........  NA...................  NA...................  0.0088 lb/MSF \3/8\''  0.016 lb/MSF \3/8\''.  NA...................  NA..................  NA.
Hardwood veneer dryer (cooling     0.058 lb/MSF \3/8\''.  NA...................  0.013 lb/MSF \3/8\''.  NA...................  NA...................  NA..................  NA.
 zones).
Hardwood veneer kilns............  0.067 lb/MSF \3/8\''.  NA...................  0.016 lb/MSF \3/8\''.  0.0053 lb/MSF \3/      NA...................  NA..................  NA.
                                                                                                         8\'',.
Humidifiers......................  0.0018 lb/MSF \1/8\''  0.0087 lb/MSF \1/8\''  0.0010 lb/MSF \1/8\''  0.00057 lb/MSF \1/     0.0000062 lb/MSF \1/   NA..................  NA.
                                                                                                         8\''.                  8\''.
I-joist curing chambers..........  NA...................  NA...................  0.00018 lb/MLF.......  NA...................  NA...................  Engineering estimate  NA.
                                                                                                                                                       if MDI resin used.
Log vats.........................  0.0047 lb/MSF \3/8\''  NA...................  NA...................  NA...................  NA...................  NA..................  NA.
                                    removed from vat per
                                    hour.
LSL presses......................  Engineering estimate.  NA...................  0.029 lb/1000 ft\3\..  Engineering estimate.  NA...................  0.18 lb/1000 ft\3\..  NA.
LVL presses......................  0.29 lb/1000 ft\3\...  NA...................  0.79 lb/1000 ft\3\...  NA...................  NA...................  NA..................  NA.
Lumber kilns.....................  0.065 lb/MBF or        0.009 lb/MBF or        0.034 lb/MBF or        0.010 lb/MBF or        NA...................  NA..................  Engineering
                                    conduct small-scale    conduct small-scale    conduct small-scale    conduct small-scale                                                 estimate.
                                    kiln testing           kiln testing           kiln testing           kiln testing
                                    according to           according to           according to           according to
                                    appendix C to          appendix C to          appendix C to          appendix C to
                                    subpart DDDD.          subpart DDDD.          subpart DDDD.          subpart DDDD.
Panel-trim chippers..............  0.00081 lb/MSF \3/     NA...................  0.00034 lb/MSF \3/     0.0019 lb/MSF \3/8\''  NA...................  NA..................  NA.
                                    8\'' finished board                           8\'' finished board    finished board
                                    production.                                   production.            production.
Particleboard press molds,         0.034 lb/MSF \3/4\''.  0.0087 lb/MSF \3/4\''  0.64 lb/MSF \3/4\''..  0.024 lb/MSF \3/4\''.  0.0073 lb/MSF \3/4\''  NA..................  NA.
 Particleboard extruders.
Radio-frequency veneer redryers..  0.0029 lb/MSF \3/8\''  NA...................  0.00065 lb/MSF \3/     NA...................  NA...................  NA..................  NA.
                                                                                  8\''.
Resin storage tanks--closed roof.  NA...................  NA...................  For tanks with resin   For tanks with resin   NA...................  For tanks with MDI    NA.
                                                                                  containing             containing phenol,                            resin, 0.0013 lb/hr
                                                                                  formaldehyde, 0.001    0.0002 lb/hr per                              per tank OR model
                                                                                  lb/hr per tank OR      tank OR model using                           using TANKS
                                                                                  model using TANKS      TANKS software\c\.                            software\c\.
                                                                                  software\c\.
Resin storage tanks--open roof...  NA...................  NA...................  Engineering estimate   Engineering estimate   NA...................  Engineering estimate  NA.
                                                                                  if resin contains      if resin contains                             if resin contains
                                                                                  formaldehyde.          phenol.                                       MDI.
Softwood plywood presses.........  0.012 lb/MSF \3/8\''.  NA...................  0.0054 lb/MSF \3/8\''  0.0022 lb/MSF \3/8\''  NA...................  NA..................  NA.
Softwood veneer dryers (cooling    0.012 lb/MSF \3/8\''.  NA...................  0.0028 lb/MSF \3/8\''  0.011 lb/MSF \3/8\''.  NA...................  NA..................  NA.
 zones).
Softwood veneer kilns............  0.097 lb/MSF \3/8\''.  0.012 lb/MSF \3/8\''.  0.10 lb/MSF \3/8\''..  0.020 lb/MSF \3/8\''.  0.0078 lb/MSF \3/8\''  NA..................  NA.

[[Page 8383]]


Stand-alone digesters............  0.030 lb/ODT.........  0.0024 lb/ODT........  0.0045 lb/ODT........  0.0012 lb/ODT........  NA...................  NA..................  NA.
Wastewater/process water           Engineering estimate   Engineering estimate   Engineering estimate   Engineering estimate   Engineering estimate   NA..................  NA.
 operations.                        (such as WATER9\c\     (such as WATER9\c\     (such as WATER9\c\     (such as WATER9\c\     (such as WATER9\c\
                                    or other method).      or other method).      or other method).      or other method).      or other method).
Wet forming--fiberboard and        0.0075 lb/MSF \1/2\''  NA...................  0.0036 lb/MSF \1/2\''  NA...................  NA...................  NA..................  NA.
 hardboard (without PF resin).
Wet forming--hardboard (PF resin)  0.0067 lb/ODT........  NA...................  0.00039 lb/ODT.......  0.00075 lb/ODT.......  NA...................  NA..................  NA.
Miscellaneous coating operations,  NA...................  NA...................  NA...................  NA...................  NA...................  NA..................  NA.
 Log chipping, Softwood veneer
 dryer fugitive emissions.
Other ancillary processes (not     Engineering estimate.  Engineering estimate.  Engineering estimate.  Engineering estimate.  Engineering estimate.  Engineering estimate  Engineering
 listed elsewhere in this table)                                                                                                                                             estimate.
 that may emit HAP listed in this
 table.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Test: Emissions testing must be conducted for the process unit and pollutant according to the test methods specified in table 2B to appendix B to subpart DDDD.
NA: Not applicable. No emission estimates or emissions tests are required for purposes of the low-risk demonstration.
lb/MSF: Pounds of HAP per thousand square feet of board of the inches thickness specified (e.g., lb/MSF \3/4\ = pounds of HAP per thousand square feet of \3/4\-inch board). See equation in
  Sec.   63.2262(j) of subpart DDDD to convert from one thickness basis to another.
lb/ODT: Pounds of HAP per oven dried ton of wood material.
lb/MBF: Pounds of HAP per thousand board feet.
lb/MLF: Pounds of HAP per thousand linear feet
\a\ Direct-fired process units firing natural gas or propane are NA; thus, no emissions estimates, emissions tests, or fuel analyses are required for the purposes of the low-risk
  demonstration.
\b\ Estimation of formaldehyde emissions is only necessary for facilities that use resin containing formaldehyde.
\c\ TANKS and WATER9 software is available at http://www.epa.gov/ttn/chief/software/index.html.



Table 2B to Appendix B to Subpart DDDD of 40 CFR part 63.--Emission Test
                                 Methods
------------------------------------------------------------------------
          For . . .              You must . . .          Using . . .
------------------------------------------------------------------------
(1) each process unit         select sampling       Method 1 or 1A of 40
 required to be tested         ports' location and   CFR part 60,
 according to table 2A to      the number of         appendix A (as
 this appendix.                traverse points.      appropriate).
(2) each process unit         determine velocity    Method 2 in addition
 required to be tested         and volumetric flow   to Method 2A, 2C,
 according to table 2A to      rate;.                2D, 2F, or 2G in
 this appendix.                                      appendix A to 40
                                                     CFR part 60 (as
                                                     appropriate).
(3) each process unit         conduct gas           Method 3, 3A, or 3B
 required to be tested         molecular weight      in appendix A to 40
 according to table 2A to      analysis.             CFR part 60 (as
 this appendix.                                      appropriate).
(4) each process unit         measure moisture      Method 4 in appendix
 required to be tested         content of the        A to 40 CFR part
 according to table 2A to      stack gas.            60.
 this appendix.
(5) each process unit         measure emissions of  NCASI Method IM/CAN/
 required to be tested         acetaldehyde.         WP-99.02 (IBR, see
 according to table 2A to                            40 CFR 63.14(f));
 this appendix.                                      OR Method 320 in
                                                     appendix A to 40
                                                     CFR part 63; OR the
                                                     NCASI Method ISS/FP-
                                                     A105.01 (IBR, see
                                                     Sec.   63.14(f));
                                                     OR Method 0011 in
                                                     ``Test Methods for
                                                     Evaluating Solid
                                                     Waste, Physical/
                                                     Chemical Methods''
                                                     (EPA Publication
                                                     No. SW-846); OR
                                                     ASTM D6348-03\b\
                                                     (IBR, see 40 CFR
                                                     63.14(b)).
(6) each process unit         measure emissions of  NCASI Method IM/CAN/
 required to be tested         acrolein.             WP-99.02 (IBR, see
 according to table 2A to                            40 CFR 63.14(f));
 this appendix.                                      OR Method 320 in
                                                     appendix A to 40
                                                     CFR part 63; OR the
                                                     NCASI Method ISS/FP-
                                                     A105.01 (IBR, see
                                                     Sec.   63.14(f));
                                                     OR ASTM D6348-03 b
                                                     (IBR, see 40 CFR
                                                     63.14(b)).

[[Page 8384]]


(7) each process unit         measure emissions of  NCASI Method IM/CAN/
 required to be tested         formaldehyde.         WP-99.02 (IBR, see
 according to table 2A to                            40 CFR 63.14(f));
 this appendix.                                      OR Method 320 in
                                                     appendix A to 40
                                                     CFR part 63; OR the
                                                     NCASI Method ISS/FP-
                                                     A105.01 (IBR, see
                                                     Sec.   63.14(f));
                                                     OR the NCASI Method
                                                     CI/WP-98.01; OR
                                                     Method 316 in
                                                     appendix A to 40
                                                     CFR part 63; OR
                                                     Method 0011 in
                                                     ``Test Methods for
                                                     Evaluating Solid
                                                     Waste, Physical/
                                                     Chemical Methods''
                                                     (EPA Publication
                                                     No. SW-846); OR
                                                     ASTM D6348-03 b
                                                     (IBR, see 40 CFR
                                                     63.14(b)).
(8) each process unit         measure emissions of  NCASI Method IM/CAN/
 required to be tested         phenol.               WP-99.02 (IBR, see
 according to table 2A to                            40 CFR 63.14(f));
 this appendix.                                      OR Method 320 in
                                                     appendix A to 40
                                                     CFR part 63; OR the
                                                     NCASI Method ISS/FP-
                                                     A105.01 (IBR, see
                                                     Sec.   63.14(f));
                                                     OR the NCASI Method
                                                     CI/WP-98.01; OR
                                                     ASTM D6348-03 b
                                                     (IBR, see 40 CFR
                                                     63.14(b)).
(9) each process unit         measure emissions of  Method 18 in
 required to be tested         benzene.              appendix A to 40
 according to table 2A to                            CFR part 60; OR
 this appendix.                                      NCASI Method IM/CAN/
                                                     WP-99.02 (IBR, see
                                                     40 CFR 63.14(f));
                                                     OR Method 320 in
                                                     appendix A to 40
                                                     CFR part 63; OR
                                                     ASTM D6348-03 b
                                                     (IBR, see 40 CFR
                                                     63.14(b)).
(10) each process unit that   measure emissions of  Method 320 in
 processes material            MDI.                  appendix A to 40
 containing MDI resin                                CFR part 63; OR
 required to be tested                               Method 207 in
 according to table 2A to                            appendix M to 40
 this appendix.                                      CFR part 51; OR
                                                     Conditional Test
                                                     Method (CTM) 031
                                                     which is posted on
                                                     http://www.epa.gov/
                                                     ttn/emc/ctm.html

(11) each direct-fired        measure emissions of  Method 29 in
 process unit a required to    the following HAP     appendix A to 40
 be tested according to        metals: Arsenic,      CFR part 60 OR fuel
 table 2A to this appendix.    beryllium, cadmium,   analysis (see
                               chromium, lead,       section 5(m) of
                               manganese, and        this appendix).
                               nickel..
(12) each reconstituted wood  meet the design       Methods 204 and 204A
 product press or              specifications        through 204F of 40
 reconstituted wood product    included in the       CFR part 51,
 board cooler with a HAP       definition of wood    appendix M to
 control device.               products enclosure    determine capture
                               in Sec.   63.2292     efficiency (except
                               of subpart DDDD of    for wood products
                               40 CFR part 63; or    enclosures as
                              determine the          defined in Sec.
                               percent capture       63.2292).
                               efficiency of the     Enclosures that
                               enclosure directing   meet the definition
                               emissions to an add-  of wood products
                               on control device.    enclosure or that
                                                     meet Method 204
                                                     requirements for a
                                                     PTE are assumed to
                                                     have a capture
                                                     efficiency of 100
                                                     percent. Enclosures
                                                     that do not meet
                                                     either the PTE
                                                     requirements or
                                                     design criteria for
                                                     a wood products
                                                     enclosure must
                                                     determine the
                                                     capture efficiency
                                                     by constructing a
                                                     TTE according to
                                                     the requirements of
                                                     Method 204 and
                                                     applying Methods
                                                     204A through 204F
                                                     (as appropriate).
                                                    As an alternative to
                                                     Methods 204 and
                                                     204A through 204F,
                                                     you may use the
                                                     tracer gas method
                                                     contained in
                                                     appendix A to
                                                     subpart DDDD.
(13) each reconstituted wood  determine the         a TTE and Methods
 product press or              percent capture       204 and 204A
 reconstituted wood product    efficiency.           through 204F (as
 board cooler required to be                         appropriate) of 40
 tested according to table                           CFR part 51,
 2A to this appendix.                                appendix M. As an
                                                     alternative to
                                                     installing a TTE
                                                     and using Methods
                                                     204 and 204A
                                                     through 204F, you
                                                     may use the tracer
                                                     gas method
                                                     contained in
                                                     appendix A to
                                                     subpart DDDD.
                                                     Enclosures that
                                                     meet the design
                                                     criteria (1)
                                                     through (4) in the
                                                     definition of wood
                                                     products enclosure,
                                                     or that meet Method
                                                     204 requirements
                                                     for a PTE (except
                                                     for the criteria
                                                     specified in
                                                     section 6.2 of
                                                     Method 204) are
                                                     assumed to have a
                                                     capture efficiency
                                                     of 100 percent.
                                                     Measured emissions
                                                     divided by the
                                                     capture efficiency
                                                     provides the
                                                     emission rate.
                                                     Fugitive emissions
                                                     are equal to the
                                                     difference in the
                                                     emission rate and
                                                     measured emissions.

[[Page 8385]]


(14) each process unit with   establish the site-   data from the
 a HAP control device          specific operating    parameter
 required to be tested         requirements          monitoring system
 according to table 2A to      (including the        or THC CEMS and the
 this appendix.                parameter limits or   applicable
                               THC concentration     performance test
                               limits) in table 2    method(s).
                               to subpart DDDD.
------------------------------------------------------------------------
a Excludes direct-fired process units fired with only natural gas or
  propane.
b Provided that percent R as determined in Annex A5 of ASTM D6348-03 is
  equal or greater than 70 percent and less than or equal to 130
  percent.


[[Page 8386]]


                                     Table 3 to Appendix B to Subpart DDDD of 40 CFR Part 63.--Maximum Allowable Toxicity-Weighted Carcinogen Emission Rate
                                                                                      [(lb/hr)/([mu]g/m3)]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Distance to property boundary  (m)
          Stack height (m)           -----------------------------------------------------------------------------------------------------------------------------------------------------------
                                           0            50          100          150          200          250          500          1000         1500         2000         3000         5000
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
5...................................     8.72E-07     8.72E-07     8.72E-07     9.63E-07     1.25E-06     1.51E-06     2.66E-06     4.25E-06     4.39E-06     4.39E-06     4.39E-06     5.00E-06
10..................................     2.47E-06     2.47E-06     2.47E-06     2.47E-06     2.47E-06     2.61E-06     3.58E-06     5.03E-06     5.89E-06     5.89E-06     5.89E-06     6.16E-06
20..................................     5.81E-06     5.81E-06     5.81E-06     5.81E-06     5.81E-06     5.81E-06     5.90E-06     7.39E-06     8.90E-06     9.97E-06     9.97E-06     1.12E-05
30..................................     7.74E-06     7.74E-06     7.74E-06     7.74E-06     7.74E-06     7.74E-06     8.28E-06     9.49E-06     1.17E-05     1.35E-05     1.55E-05     1.61E-05
40..................................     9.20E-06     9.20E-06     9.20E-06     9.20E-06     9.20E-06     9.20E-06     9.24E-06     1.17E-05     1.34E-05     1.51E-05     1.98E-05     2.22E-05
50..................................     1.02E-05     1.02E-05     1.02E-05     1.02E-05     1.02E-05     1.02E-05     1.02E-05     1.36E-05     1.53E-05     1.66E-05     2.37E-05     2.95E-05
60..................................     1.13E-05     1.13E-05     1.13E-05     1.13E-05     1.13E-05     1.13E-05     1.13E-05     1.53E-05     1.76E-05     1.85E-05     2.51E-05     3.45E-05
70..................................     1.23E-05     1.23E-05     1.23E-05     1.23E-05     1.23E-05     1.23E-05     1.23E-05     1.72E-05     2.04E-05     2.06E-05     2.66E-05     4.07E-05
80..................................     1.34E-05     1.34E-05     1.34E-05     1.34E-05     1.34E-05     1.34E-05     1.34E-05     1.92E-05     2.15E-05     2.31E-05     2.82E-05     4.34E-05
100.................................     1.52E-05     1.52E-05     1.52E-05     1.52E-05     1.52E-05     1.52E-05     1.52E-05     1.97E-05     2.40E-05     2.79E-05     3.17E-05     4.49E-05
200.................................     1.76E-05     1.76E-05     1.76E-05     1.76E-05     1.76E-05     1.76E-05     1.76E-05     2.06E-05     2.94E-05     3.24E-05     4.03E-05    5.04E-05
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
MIR=1E-06.


                                    Table 4 to Appendix B to Subpart DDDD of 40 CFR Part 63.--Maximum Allowable Toxicity-Weighted Noncarcinogen Emission Rate
                                                                                      [(lb/hr)/([mu]g/m3)]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Distance to property boundary  (m)
          Stack height  (m)          -----------------------------------------------------------------------------------------------------------------------------------------------------------
                                           0            50          100          150          200          250          500          1000         1500         2000         3000         5000
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
5...................................     2.51E-01     2.51E-01     3.16E-01     3.16E-01     3.16E-01     3.16E-01     3.16E-01     3.46E-01     4.66E-01     6.21E-01     9.82E-01     1.80E+00
10..................................     5.62E-01     5.62E-01     5.62E-01     5.62E-01     5.62E-01     5.62E-01     5.62E-01     5.70E-01     6.33E-01     7.71E-01     1.13E+00     1.97E+00
20..................................     1.43E+00     1.43E+00     1.43E+00     1.43E+00     1.43E+00     1.43E+00     1.43E+00     1.43E+00     1.68E+00     1.83E+00     2.26E+00     3.51E+00
30..................................     2.36E+00     2.36E+00     2.36E+00     2.36E+00     2.36E+00     2.36E+00     2.53E+00     3.04E+00     3.04E+00     3.33E+00     4.45E+00     5.81E+00
40..................................     3.11E+00     3.11E+00     3.11E+00     3.11E+00     3.11E+00     3.11E+00     3.42E+00     4.04E+00     5.07E+00     5.51E+00     6.39E+00     9.63E+00
50..................................     3.93E+00     3.93E+00     3.93E+00     3.93E+00     3.93E+00     3.93E+00     4.49E+00     4.92E+00     6.95E+00     7.35E+00     8.99E+00     1.25E+01
60..................................     4.83E+00     4.83E+00     4.83E+00     4.83E+00     4.83E+00     4.83E+00     5.56E+00     6.13E+00     7.80E+00     1.01E+01     1.10E+01     1.63E+01
70..................................     5.77E+00     5.77E+00     5.77E+00     5.77E+00     5.77E+00     5.77E+00     6.45E+00     7.71E+00     8.83E+00     1.18E+01     1.36E+01     1.86E+01
80..................................     6.74E+00     6.74E+00     6.74E+00     6.74E+00     6.74E+00     6.74E+00     7.12E+00     9.50E+00     1.01E+01     1.29E+01     1.72E+01     2.13E+01
100.................................     8.87E+00     8.87E+00     8.87E+00     8.87E+00     8.87E+00     8.87E+00     8.88E+00     1.19E+01     1.37E+01     1.55E+01     2.38E+01     2.89E+01
200.................................     1.70E+01     1.70E+01     1.70E+01     1.70E+01     1.70E+01     1.70E+01     1.70E+01     2.05E+01     2.93E+01     3.06E+01     4.02E+01    4.93E+01
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 HI=1.


[[Page 8387]]


0
13. Add appendix C to subpart DDDD to read as follows:

Appendix C to Subpart DDDD of Part 63--Considerations for a Small-Scale 
Kiln Emission Testing Program

1.0 Purpose

    Emissions test data from small-scale lumber kilns can be used to 
reasonably approximate emissions from full-scale lumber kilns if 
representative lumber samples are dried and the venting 
characteristics of the small-scale kiln mimic those of the full-
scale kiln. This appendix provides a list of considerations that 
must be taken into account by facilities conducting small-scale 
lumber kiln emissions testing to approximate emissions from their 
full-scale lumber kilns for purposes of the low-risk demonstration 
described under appendix B to subpart DDDD of part 63.
    The considerations described in this appendix apply only for 
small-scale lumber kiln emissions testing conducted to provide data 
for the low-risk demonstration described under appendix B to subpart 
DDDD of part 63. Permitting authorities may require different 
procedures for testing or estimating lumber kiln emissions for 
purposes other than the low-risk demonstration described under 
appendix B to subpart DDDD of part 63.

2.0 Considerations for Lumber Samples

    2.1 A written plan must be developed for obtaining 
representative lumber samples to use as charges at the small-scale 
kilns. The plan must discuss how the samples are selected and 
handled and the basis upon which they are considered to be 
representative. If possible, information on the harvest site, date 
harvested, segregation from other lumber (if segregated), and 
processing at the sawmill must be included. If this information is 
unavailable, a general description of the sawmill's wood procurement 
and processing practices must be provided. The affected source and 
testing laboratory must approve the written test plan before 
beginning the small-scale kiln testing.
    2.2 Samples must not be subject to significant air drying during 
processing, shipping, or storage prior to charging into the small-
scale kiln.
    2.3 Enough lumber must be collected to provide for extra lumber 
charges in case of testing failures.
    2.4 Information on the lumber used for each small-scale kiln 
charge must be reported including the items in paragraphs 2.4.1 
though 2.4.4 of this section:
    2.4.1 Total kiln charge, board feet,
    2.4.2 Nominal dimensions of lumber dried (for example, 2x4s),
    2.4.3 Moisture content (dry basis) of the green lumber, and
    2.4.4 Moisture content (dry basis) of the kiln dried lumber.

3.0 Considerations for Kiln Operating Parameters

    The small-scale kiln must operate in a similar manner to the 
full-scale kilns for items 3.1 through 3.3 of this section. The 
small-scale kiln must operate in a reasonably consistent manner from 
charge-to-charge for all items (3.1 through 3.5) listed in this 
section.
    3.1 Air velocity through the kiln charge.
    3.2 Temperature profiles or kiln schedules (wet-bulb/dry-bulb 
temperatures throughout the kiln cycle).
    3.3 Ending moisture content (dry basis) of the lumber (may need 
to be mathematically adjusted for small-scale kilns).
    3.4 Kiln venting profile (trend) for the sample event/kiln cycle 
(normalized to a board foot or thousand board feet).
    3.5 Mass emission rate profile (trend) for the sample event/kiln 
cycle.

4.0 Considerations for Emission Sampling

    4.1 Sample equipment must be able to sample gases with high 
moisture content.
    4.2 You must accurately measure/calculate total kiln exhaust and 
exhaust moisture content. If direct measurements are impractical 
other methods used must be explicitly discussed in the report.
    4.3 You must accurately measure the concentration of the 
compounds of concern either in the kiln exhaust or at a proper 
location within the kiln.

5.0 Considerations for Sample Intervals and Sampling Runs

    5.1 A minimum of two full kiln cycles or batches must be tested 
to determine the emissions for a particular wood species or for a 
facility utilizing only one wood species.
    5.2 You may use a single kiln cycle for emission values for wood 
species that require more than 3 days to dry.
    5.3 Since kiln drying cycles typically exceed 20 hours, it is 
suggested that sampling be conducted in intervals throughout the 
drying cycle. Three hours provide a reasonable sample interval 
(sample run), but sampling equipment or manpower may dictate other 
schedules. Sampling equipment ``turnaround'' will result in gaps in 
the kiln emission data. The gaps must not exceed 45% of the kiln 
cycle. Data for the gaps occurring at certain periods of time in the 
drying cycle can be calculated by linear interpolation from the 
sampling values on either side of the gap. Other techniques may be 
required if the data gap occurs when the measured data exhibit high 
levels of variability. As a minimum, sampling intervals must include 
initial hours of the kiln operating cycle once the kiln has warmed 
to target wet bulb and/or dry bulb temperatures and begins venting, 
hours of kiln operation during the middle of the kiln drying cycle, 
and hours of kiln operation towards the end of the kiln drying 
cycle.
    5.4 The final production-based mass emission rate for the small-
scale kiln sample event is determined by integrating the area under 
the mass emission rate profile curve.

6.0 Considerations for Reporting

    The emissions report must contain the information in paragraphs 
6.1 through 6.9 of this section.
    6.1 Graphical, charge-by-charge results for items 3.2, 3.4, and 
3.5 above and numerical data for items 3.1 and 3.3. Describe how the 
full-scale kiln operates in comparison to the small-scale kiln in 
order to show that the full-scale kiln drying cycle was reasonably 
reproduced in the small-scale kiln.
    6.2 A moisture balance by comparing the water loss (from the 
green versus dry lumber charge weight difference) to the water 
exhausted from the kiln (using the exhaust flow rate and moisture 
content of the exhaust).
    6.3 A description of the sampling system and sampling 
methodology.
    6.4 A summary and background data for all quality assurance 
measures required by the sampling methods.
    6.5 Discussion of method detection limits and treatment of 
values below the detection limit.
    6.6 An example of emission rate calculations.
    6.7 Explanation or reference to the methodology used to 
calculate emissions to the target or desired ending lumber moisture 
content.
    6.8 Information outlined in section 2.0 of this appendix, 
including a discussion of collection and handling of lumber samples.
    6.9 Data and show calculations for developed emission factors.

7.0 Guidance

    7.1 NCASI Technical Bulletin 845 provides a large amount of 
detail that can be of assistance in many phases of a small-scale 
kiln testing program. This report should be viewed as ``one way,'' 
not ``the only way'' to conduct testing.
    7.2 Oregon State University, Mississippi State University, the 
University of Idaho, and others have published information regarding 
operation and testing of small-scale kilns. These publications are a 
very good source of information on small-scale kilns.
[FR Doc. 06-1071 Filed 2-15-06; 8:45 am]

BILLING CODE 6560-50-P
