Thursday, 

February 16, 2006 

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 


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8342 Federal Register / Vol. 71, No. 32 / Thursday, February 16, 2006 / Rules and Regulations 

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 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 

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; email address: kissell.mary@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Regulated Entities 

Categories and entities potentially 

affected by today’s action include: 

Category SIC 

code a

NAICS 

code b Examples of 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 § 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 


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Federal Register / Vol. 71, No. 32 / Thursday, February 16, 2006 / Rules and Regulations 8343 

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. 

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 lowrisk 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. 

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 riskbased 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 lookup 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 


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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 Lowrisk 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 MACTregulated 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 riskbased 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-bysource 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 


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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 nonlow-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 riskbased 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 


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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 CoLocated 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 colocated 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 nonthreshold 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 


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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 riskbased 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 lowrisk 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 doseresponse 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 


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2U.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) 

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 doseresponse 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 ecosystemprotective 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 peerreviewed 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. 

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 bestavailable science for our risk 

assessments. In situations where the 

IRIS assessment lags behind current 

scientific knowledge and newer peerreviewed 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, 


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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 bestavailable 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 bestavailable 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 higheremitting 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 toxicityweighted 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 lookup 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 healthprotective 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 healthprotective 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 


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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 doseresponse 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 doseresponse 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 doseresponse 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 noncancer 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 postproposal 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 


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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 lowrisk 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, worstcase 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 sitespecific 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 chemicalspecific 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 doseresponse 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 lookup 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 sitespecific 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 


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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 sitespecific 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, peerreviewed 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 qualityassured 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 


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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 statisticallyderived 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 


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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 smallscale 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 overestimated 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 (shortterm) 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 


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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 § (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 opentop 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 lowrisk 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 HAPcontaining 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% nonformaldehyde 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. 


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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 § 63.7521(a) and (c) 

through (e); § 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 


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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 


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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 lowrisk 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 productionbased compliance option) should the 

facility decide not to pursue the lowrisk 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 § 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 


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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 lowrisk 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. 


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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 lowrisk 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 lowrisk 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 lowrisk. 

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 ‘‘resubject’’ 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 lowrisk 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 lowrisk 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 lowrisk 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, 


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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 

§ 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 preconstruction 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 prestartup 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 prestartup 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 prestartup LRD prior to startup. The source 

must operate, and certify they are 

operating, consistently with their prestartup 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 prestartup 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 


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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 lowrisk 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 


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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 

§ 70.7(e)(2)(i)(A)(3), regarding 

establishment or changes of case-by-case 

determinations of an emission 

limitation or other standard, and 

§§ 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 lowrisk 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 lowrisk 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 


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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 overburdening 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 


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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 sitespecific 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 


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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 groundlevel 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 


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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 ‘‘directfired 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 ‘‘directfired 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 directfire 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 directfired 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 ‘‘directfired process unit’’ accordingly as 

suggested by the commenter. However, 

if the indirect heat exhaust stream does 

not routinely pass through the directfired 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. 


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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 

§ 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 § 63.2271 

specifies that sources must demonstrate 

that they were acting in accordance with 

§ 63.6(e) of the General Provisions 

during an SSM event. Therefore, when 

the General Provisions proposed 

amendments are finalized, most likely 


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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 

§ 63.2250(a), the section that describes 

when the SSM provisions apply. One 

commenter mostly supported the 

proposed amendment but stated that 

§ 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 § 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 

§ 63.2250(b). Sources should refer to 

§ 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 


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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 costeffective, 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 


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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 §§ 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. 

■ 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] 

■ 1. The authority citation for part 63 

continues to read as follows: 

Authority: 42 U.S.C. 7401. 

Subpart A—[Amended] 

■ 2. Section 63.14 is amended by adding 

paragraph (f)(4) to read as follows: 

§ 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 

■ 3. Section 63.2232 is amended by 

revising paragraph (b) to read as follows: 


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§ 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 (§ 63.2292). The 

affected source includes lumber kilns at 

PCWP manufacturing facilities and at 

any other kind of facility. 

* * * * * 

■ 4. Section 63.2233 is amended by 

revising paragraphs (b) and (c) to read 

as follows: 

§ 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. 

* * * * * 

■ 5. Section 63.2250 is amended by 

revising paragraph (a) to read as follows: 

§ 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 § 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. 

* * * * * 

■ 6. Section 63.2252 is added to read as 

follows: 

§ 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 § 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 § 63.9(b). 

■ 7. Section 63.2262 is amended by 

revising paragraph (d)(1) to read as 

follows: 

§ 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 § 63.2292) and prior to any releases 

to the atmosphere. For control 

sequences with wet control devices 

(defined in § 63.2292) followed by 

control devices (defined in § 63.2292), 

sampling sites may be located at the 

inlet and outlet of the control sequence 

and prior to any releases to the 

atmosphere. 

* * * * * 

■ 8. Section 63.2269 is amended by 

revising the introductory text of 

paragraph (c) to read as follows: 

§ 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. 

* * * * * 

■ 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: 

§ 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, 


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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 wetformed 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 § 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 wetformed 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. 

* * * * * 

■ 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 subject to a compliance 

option in table 1A or 1B to this subpart or 

used in calculation of an emissions average 

under § 63.2240(c).

select sampling port’s location and the number of traverse ports.Method 1 or 1A of 40 CFR part 60, appendix 

A (as appropriate). 

(2) each process unit subject to a compliance 

option in table 1A or 1B to this subpart or 

used in calculation of an emissions average 

under § 63.2240(c).

determine velocity and volumetric flow rate .... Method 2 in addition to Method 2A, 2C, 2D, 

2F, or 2G in appendix A to 40 CFR part 60 

(as appropriate). 

(3) each process unit subject to a compliance 

option in table 1A or 1B to this subpart or 

used in calculation of an emissions average 

under § 63.2240(c).

conduct gas molecular weight analysis ........... Method 3, 3A, or 3B in appendix A to 40 CFR 

part 60 (as appropriate). 

(4) each process unit subject to a compliance 

option in table 1A or 1B to this subpart or 

used in calculation of an emissions average 

under § 63.2240(c).

measure moisture content of the stack gas .... Method 4 in appendix A to 40 CFR part 60; 

OR Method 320 in appendix A to 40 CFR 

part 63; OR ASTM D6348–03 (IBR, see 

§ 63.14(b)). 

(5) each process unit subject to a compliance 

option in table 1B to this subpart for which 

you choose to demonstrate compliance using 

a total HAP as THC compliance option.

measure emissions of total HAP as THC ........ Method 25A in appendix A to 40 CFR part 60. 

You may measure emissions of methane 

using EPA Method 18 in appendix A to 40 

CFR part 60 and subtract the methane 

emissions from the emissions of total HAP 

as THC. 


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TABLE 4 TO SUBPART DDDD OF PART 63.—REQUIREMENTS FOR PERFORMANCE TESTS—Continued 

For . . . You must . . . Using . . . 

(6) each process unit subject to a compliance 

option in table 1A to this subpart; OR for 

each process unit used in calculation of an 

emissions average under § 63.2240(c).

measure emissions of total HAP (as defined 

in § 63.2292).

Method 320 in appendix A to 40 CFR part 63; 

OR the NCASI Method IM/CAN/WP–99.02 

(IBR, see § 63.14(f)); OR the NCASI Method ISS/FP–A105.01 (IBR, see § 63.14(f)); 

OR ASTM D6348–03 (IBR, see § 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 subject to a compliance 

option in table 1B to this subpart for which 

you choose to demonstrate compliance using 

a methanol compliance option.

measure emissions of methanol ...................... Method 308 in appendix A to 40 CFR part 63; 

OR Method 320 in appendix A to 40 CFR 

part 63; OR the NCASI Method CI/WP–

98.01 (IBR, see § 63.14(f)); OR the NCASI 

Method IM/CAN/WP–99.02 (IBR, see 

§ 63.14(f)); OR the NCASI Method ISS/FP–

A105.01 (IBR, see § 63.14(f)). 

(8) each process unit subject to a compliance 

option in table 1B to this subpart for which 

you choose to demonstrate compliance using 

a formaldehyde compliance option.

measure emissions of formaldehyde ............... Method 316 in appendix A to 40 CFR part 63; 

OR Method 320 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) for formaldehyde; OR the NCASI 

Method CI/WP–98.01 (IBR, see § 63.14(f)); 

OR the NCASI Method IM/CAN/WP–99.02 

(IBR, see § 63.14(f)); OR the NCASI Method ISS/FP–A105.01 (IBR, see § 63.14(f)). 

(9) each reconstituted wood product press at a 

new or existing affected source or reconstituted wood product board cooler at a new affected source subject to a compliance option 

in table 1B to this subpart or used in calculation of an emissions average under 

§ 63.2240(c).

meet the design specifications included in the 

definition of wood products enclosure in 

§ 63.2292; or 

determine the percent capture efficiency of 

the enclosure directing emissions to an 

add-on control device.

Methods 204 and 204A through 204F of 40 

CFR part 51, appendix M, to determine 

capture efficiency (except for wood products enclosures as defined in § 63.2292). 

Enclosures that meet the definition 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 product press at 

a new or existing affected source or reconstituted wood product board cooler at a new affected source subject to a compliance option 

in table 1A to this subpart.

determine the percent capture efficiency ........ a TTE and Methods 204 and 204A through 

204F (as appropriate) of 40 CFR part 51, 

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 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 subject to a compliance 

option in tables 1A and 1B to this subpart or 

used in calculation of an emissions average 

under § 63.2240(c).

establish the site-specific operating requirements (including the parameter limits or 

THC concentration limits) in table 2 to this 

subpart.

data from the parameter monitoring system or 

THC CEMS and the applicable performance 

test method(s). 


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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 

■ 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 pretest 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. 

* * * * * 

■ 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 § 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 sitespecific 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 § 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 § 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 


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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 § 63.7521 (a) and (c) through (e) 

of subpart DDDDD; § 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. 

TWCER ER Eqn = × ∑( ) i URE 1 i .

TWCER = Toxicity-weighted carcinogenic 

emission rate for each emission point 

(lb/hr)/(μg/m3) 

ERi = Emission rate of pollutant i (lb/hr) UREi = Unit risk estimate for pollutant i, 1 

per microgram per cubic meter (μg/ 

m3)¥1

TWNER ER Eqn = ∑( ) i RfC 2 i .

TWNER = Toxicity-weighted 

noncarcinogenic emission rate for each 

emission point (lb/hr)/(μg/m3) 

ERi = Emission rate of pollutant i (lb/hr) 

RfCi = Reference concentration for pollutant 

i, micrograms per cubic meter (μg/m3) 

WHC

TWCE

TWCER

H Eqn ep

ep

ep

ep n ep

ep

ep n

= ×

=

=

=

=

∑

∑ R .

1

1

 3

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 


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WHN

TWNER

TWNER

H Eqn ep

EP

ep

ep n

ep

ep n

= ep

























×

=

=

=

=

∑

∑

1

1

. 4

WHN = Non-carcinogen weighted stack 

height for use in the non-carcinogen lookup 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 toxicityweighted carcinogen emission rate for your 

affected source by summing the toxicityweighted carcinogen emission rates for each 

of your emission points. Identify the 

appropriate maximum allowable toxicityweighted 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 noncarcinogen 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 scientificallyaccepted 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 doseresponse 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 lowrisk 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 


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that your affected source remains in the lowrisk 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 lookup 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 lowrisk 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 lowrisk demonstration. 

(iii) If EPA approves your pre-startup lowrisk 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 lowrisk demonstration developed according to 

paragraph (c)(2) of this section. Failure to so 

operate will render approval of your prestartup 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 lowrisk 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 EPAapproved 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 prestartup 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 


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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 lowrisk 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 EPAapproved 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 § 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 §§ 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 

§ 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 lowrisk 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 lowrisk 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 lowrisk 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 § 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 § 63.2282(c) of 40 CFR 

part 63, subpart DDDD. 


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15. Definitions 

The definitions in § 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 wetformed 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 watersoluble 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 radiofrequency 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 nonhydrocarbon 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 upperbound excess lifetime cancer risk estimated 

to result from continuous exposure to an 

agent at a concentration of 1 microgram per 

cubic meter (μg/m3) in air. 

Wastewater/process water operation means 

equipment that processes water in plywood 

or composite wood product facilities for 


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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 effects . . . You must include the following HAP . . . 

(1) Chronic inhalation carcinogenic effects .............................................. acetaldehyde, benzene, arsenic, beryllium, cadmium, chromium, lead, 

nickel, and formaldehyde. 

(2) Chronic inhalation noncarcinogenic respiratory effects ...................... acetaldehyde, acrolein, cadmium, formaldehyde, and methylene diphenyl diisocyanate (MDI). 

(3) Chronic inhalation noncarcinogenic CNS effects ............................... manganese, lead, and phenol. 

(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

Process unit type Acetaldehyde Acrolein Formaldehyde Phenol Benzene MDI 

HAP metals 

from directfired process 

units a

Agricultural fiberboard mat 

dryers, Dry rotary dryers, 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).

Test .............. Test .............. Test .............. Test .............. Test .............. NA ................ Test or fuel 

analysis. 

Atmospheric refiners, Conveyor strand dryers, Pressurized refiners.Test .............. Test .............. Test .............. Test .............. Test .............. NA ................ NA. 

Primary tube dryers, Secondary tube dryers.Test .............. Test .............. Test .............. Test .............. Test .............. Test if processing furnish with 

MDI resin 

added prior 

to drying.

Test or fuel 

analysis. 

Agricultural fiber board presses, Reconstituted wood 

products presses, Reconstituted wood product board 

coolers.

Test .............. Test .............. Test .............. Test .............. Test .............. Test if board 

contains 

MDI resin.

NA 

Blending and forming operations—particleboard and 

MDF.

NA ................ NA ................ 0.060 lb/ 

ODTb.

NA ................ NA ................ Engineering 

estimate if 

MDI resin 

used.

NA. 

Blending and forming operations—OSB.NA ................ NA ................ 0.0036 lb/ 

MSF 3⁄8′′ 

press 

throughput.

Engineering 

estimate.

NA ................ Engineering 

estimate if 

MDI resin 

used.

NA. 

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 

emissions).

0.0055 lb/ 

MSF 1⁄2′′.

NA ................ 0.031 lb/MSF 1⁄2′′.NA ................ NA ................ NA ................ NA. 


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TABLE 2A TO APPENDIX B TO SUBPART DDDD OF 40 CFR PART 63.—TESTING AND EMISSIONS ESTIMATION

SPECIFICATIONS FOR PROCESS UNITS—Continued 

Process unit type Acetaldehyde Acrolein Formaldehyde Phenol Benzene MDI 

HAP metals 

from directfired process 

units a

Finishing sanders ................... 0.0031 lb/ 

MSF.

NA ................ 0.0042 lb/ 

MSF.

0.015 lb/MSF NA ................ Engineering 

estimate if 

MDI resin 

used.

NA. 

Finishing saws ........................ 0.00092 lb/ 

MSF 3⁄8′′.

NA ................ 0.00034 lb/ 

MSF 3⁄8′′.

0.0057 lb/ 

MSF.

NA ................ Engineering 

estimate if 

MDI resin 

used.

NA. 

Hardwood plywood presses ... NA ................ NA ................ 0.0088 lb/ 

MSF 3⁄8′′.

0.016 lb/MSF 3⁄8′′.NA ................ NA ................ NA. 

Hardwood veneer dryer (cooling zones).0.058 lb/MSF 3⁄8′′.NA ................ 0.013 lb/MSF 3⁄8′′.NA ................ NA ................ NA ................ NA. 

Hardwood veneer kilns ........... 0.067 lb/MSF 3⁄8′′.NA ................ 0.016 lb/MSF 3⁄8′′.0.0053 lb/ 

MSF 3⁄8′′,.

NA ................ NA ................ NA. 

Humidifiers .............................. 0.0018 lb/ 

MSF 1⁄8′′.

0.0087 lb/ 

MSF 1⁄8′′.

0.0010 lb/ 

MSF 1⁄8′′.

0.00057 lb/ 

MSF 1⁄8′′.

0.0000062 lb/ 

MSF 1⁄8′′.

NA ................ NA. 

I-joist curing chambers ........... NA ................ NA ................ 0.00018 lb/ 

MLF.

NA ................ NA ................ Engineering 

estimate if 

MDI resin 

used.

NA. 

Log vats .................................. 0.0047 lb/ 

MSF 3⁄8′′ 

removed 

from vat 

per hour.

NA ................ NA ................ NA ................ NA ................ NA ................ NA. 

LSL presses ............................ Engineering 

estimate.

NA ................ 0.029 lb/1000 

ft3.

Engineering 

estimate.

NA ................ 0.18 lb/1000 

ft3.

NA. 

LVL presses ............................ 0.29 lb/1000 

ft3.

NA ................ 0.79 lb/1000 

ft3.

NA ................ NA ................ NA ................ NA. 

Lumber kilns ........................... 0.065 lb/MBF 

or conduct 

small-scale 

kiln testing 

according 

to appendix 

C to subpart DDDD.

0.009 lb/MBF 

or conduct 

small-scale 

kiln testing 

according 

to appendix 

C to subpart DDDD.

0.034 lb/MBF 

or conduct 

small-scale 

kiln testing 

according 

to appendix 

C to subpart DDDD.

0.010 lb/MBF 

or conduct 

small-scale 

kiln testing 

according 

to appendix 

C to subpart DDDD.

NA ................ NA ................ Engineering 

estimate. 

Panel-trim chippers ................. 0.00081 lb/ 

MSF 3⁄8′′ 

finished 

board production.

NA ................ 0.00034 lb/ 

MSF 3⁄8′′ 

finished 

board production.

0.0019 lb/ 

MSF 3⁄8′′ 

finished 

board production.

NA ................ NA ................ NA. 

Particleboard press molds, 

Particleboard extruders.

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. 

Radio-frequency veneer redryers.0.0029 lb/ 

MSF 3⁄8′′.

NA ................ 0.00065 lb/ 

MSF 3⁄8′′.

NA ................ NA ................ NA ................ NA. 

Resin storage tanks—closed 

roof.

NA ................ NA ................ For tanks 

with resin 

containing 

formaldehyde, 0.001 

lb/hr per 

tank OR 

model 

using 

TANKS 

softwarec.

For tanks 

with resin 

containing 

phenol, 

0.0002 lb/ 

hr per tank 

OR model 

using 

TANKS 

softwarec.

NA ................ For tanks 

with MDI 

resin, 

0.0013 lb/ 

hr per tank 

OR model 

using 

TANKS 

softwarec.

NA. 

Resin storage tanks—open 

roof.

NA ................ NA ................ Engineering 

estimate if 

resin contains formaldehyde.

Engineering 

estimate if 

resin contains phenol.

NA ................ Engineering 

estimate if 

resin contains MDI.

NA. 

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 zones).0.012 lb/MSF 3⁄8′′.NA ................ 0.0028 lb/ 

MSF 3⁄8′′.

0.011 lb/MSF 3⁄8′′.NA ................ NA ................ NA. 

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. 


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TABLE 2A TO APPENDIX B TO SUBPART DDDD OF 40 CFR PART 63.—TESTING AND EMISSIONS ESTIMATION

SPECIFICATIONS FOR PROCESS UNITS—Continued 

Process unit type Acetaldehyde Acrolein Formaldehyde Phenol Benzene MDI 

HAP metals 

from directfired process 

units a

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 operations.Engineering 

estimate 

(such as 

WATER9c

or other 

method).

Engineering 

estimate 

(such as 

WATER9c

or other 

method).

Engineering 

estimate 

(such as 

WATER9c

or other 

method).

Engineering 

estimate 

(such as 

WATER9c

or other 

method).

Engineering 

estimate 

(such as 

WATER9c

or other 

method).

NA ................ NA. 

Wet forming—fiberboard and 

hardboard (without PF 

resin).

0.0075 lb/ 

MSF 1⁄2′′.

NA ................ 0.0036 lb/ 

MSF 1⁄2′′.

NA ................ NA ................ NA ................ NA. 

Wet forming—hardboard (PF 

resin).

0.0067 lb/ 

ODT.

NA ................ 0.00039 lb/ 

ODT.

0.00075 lb/ 

ODT.

NA ................ NA ................ NA. 

Miscellaneous coating operations, Log chipping, 

Softwood veneer dryer fugitive emissions.

NA ................ NA ................ NA ................ NA ................ NA ................ NA ................ NA. 

Other ancillary processes (not 

listed elsewhere in this 

table) that may emit HAP 

listed in this table.

Engineering 

estimate.

Engineering 

estimate.

Engineering 

estimate.

Engineering 

estimate.

Engineering 

estimate.

Engineering 

estimate.

Engineering 

estimate. 

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 § 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. bEstimation of formaldehyde emissions is only necessary for facilities that use resin containing formaldehyde. 

cTANKS 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 required to be tested according to table 2A to this appendix.select sampling ports’ location and the number of traverse points.Method 1 or 1A of 40 CFR part 60, appendix 

A (as appropriate). 

(2) each process unit required to be tested according to table 2A to this appendix.determine velocity and volumetric flow rate; ... Method 2 in addition to Method 2A, 2C, 2D, 

2F, or 2G in appendix A to 40 CFR part 60 

(as appropriate). 

(3) each process unit required to be tested according to table 2A to this appendix.conduct gas molecular weight analysis ........... Method 3, 3A, or 3B in appendix A to 40 CFR 

part 60 (as appropriate). 

(4) each process unit required to be tested according to table 2A to this appendix.measure moisture content of the stack gas .... Method 4 in appendix A to 40 CFR part 60. 

(5) each process unit required to be tested according to table 2A to this appendix.measure emissions of acetaldehyde ............... 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 the NCASI 

Method ISS/FP–A105.01 (IBR, see 

§ 63.14(f)); OR Method 0011 in ‘‘Test Methods for Evaluating Solid Waste, Physical/ 

Chemical Methods’’ (EPA Publication No. 

SW–846); OR ASTM D6348–03b (IBR, see 

40 CFR 63.14(b)). 

(6) each process unit required to be tested according to table 2A to this appendix.measure emissions of acrolein ........................ 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 the NCASI 

Method ISS/FP–A105.01 (IBR, see 

§ 63.14(f)); OR ASTM D6348–03 b (IBR, see 

40 CFR 63.14(b)). 


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8384 Federal Register / Vol. 71, No. 32 / Thursday, February 16, 2006 / Rules and Regulations 

TABLE 2B TO APPENDIX B TO SUBPART DDDD OF 40 CFR PART 63.—EMISSION TEST METHODS—Continued 

For . . . You must . . . Using . . . 

(7) each process unit required to be tested according to table 2A to this appendix.measure emissions of formaldehyde ............... 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 the NCASI 

Method ISS/FP–A105.01 (IBR, see 

§ 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 required to be tested according to table 2A to this appendix.measure emissions of phenol .......................... 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 the NCASI 

Method ISS/FP–A105.01 (IBR, see 

§ 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 required to be tested according to table 2A to this appendix.measure emissions of benzene ....................... Method 18 in appendix A to 40 CFR part 60; 

OR 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 processes material 

containing MDI resin required to be tested 

according to table 2A to this appendix.

measure emissions of MDI .............................. Method 320 in appendix A to 40 CFR part 63; 

OR Method 207 in appendix M to 40 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 process unit a required to 

be tested according to table 2A to this appendix.

measure emissions of the following HAP metals: Arsenic, beryllium, cadmium, chromium, 

lead, manganese, and nickel..

Method 29 in appendix A to 40 CFR part 60 

OR fuel analysis (see section 5(m) of this 

appendix). 

(12) each reconstituted wood product press or 

reconstituted wood product board cooler with 

a HAP control device.

meet the design specifications included in the 

definition of wood products enclosure in 

§ 63.2292 of subpart DDDD of 40 CFR part 

63; or 

determine the percent capture efficiency of 

the enclosure directing emissions to an 

add-on control device.

Methods 204 and 204A through 204F of 40 

CFR part 51, appendix M to determine capture efficiency (except for wood products 

enclosures as defined in § 63.2292). Enclosures that meet the definition of wood products 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 product press or 

reconstituted wood product board cooler required to be tested according to table 2A to 

this appendix.

determine the percent capture efficiency ........ a TTE and Methods 204 and 204A through 

204F (as appropriate) of 40 CFR part 51, 

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. 


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Federal Register / Vol. 71, No. 32 / Thursday, February 16, 2006 / Rules and Regulations 8385 

TABLE 2B TO APPENDIX B TO SUBPART DDDD OF 40 CFR PART 63.—EMISSION TEST METHODS—Continued 

For . . . You must . . . Using . . . 

(14) each process unit with a HAP control device required to be tested according to table 

2A to this appendix.

establish the site-specific operating requirements (including the parameter limits or 

THC concentration limits) in table 2 to subpart DDDD.

data from the parameter monitoring system or 

THC CEMS and the applicable performance 

test method(s). 

aExcludes direct-fired process units fired with only natural gas or propane. 

bProvided 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. 


dsatterwhite on PROD1PC65 with RULES2
8386 Federal Register / Vol. 71, No. 32 / Thursday, February 16, 2006 / Rules and Regulations 

TABLE 3 TO

APPENDIX B TO

SUBPART DDDD OF 40 CFR PART 63.

—

MAXIMUM

ALLOWABLE

TOXICITY-WEIGHTED

CARCINOGEN

EMISSION

RATE

[(lb/hr)/(μg/m3)] 

Stack height (m) 

Distance to property boundary 

(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)/(μg/m3)] 

Stack height 

(m) 

Distance to property boundary 

(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. 


dsatterwhite on PROD1PC65 with RULES2
Federal Register / Vol. 71, No. 32 / Thursday, February 16, 2006 / Rules and Regulations 8387 

■ 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 


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