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OAR Box 1793 

Prepped by Keeia Richards 

Document Number: 

22) ll-F-64 

Docket Number: 

A-90-37 

Printed 11/3/2008 11:31:54 AM Sheet 22 of 45 
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U. S. Environmental Protection Agency 

Research Triangle Park, NC 27711 

FAX Number: (919)541-5509 frlOSy 

fmONINlAOaT 

919-541- S-s*?:? 

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findings. For example, in a PSD permit appeal proceeding, the 

EPA's Environmental Appeals Board held that the permitting 

authority erred in summarily rejecting the demonstrations of the 

FLMs for the Shenandoah National Park and James River Face 

Wilderness that the proposed facility would have an adverse 

impact on AQRVs in those Federal Class I areas.60 

In an effort to provide clearer guidance and promote more 

reasoned decision-making, the EPA is proposing to establish 

considerations that must inform a permitting authority's 

rejection of the FLM's demonstration of an adverse impact on 

AQRVs. In doing so, the EPA has tried to balance the «3eiftjp<efc*ftg-^~ 

statutory provisions concerning the affirmative responsibility 

given to the FLM to protect fcke AQRVS <5£"Fodoral'""Glflsg-i' txx*o&&^ 

and the stipulation that the permitting authority must be 

satisfied with the FLM's demonstration of adverse impact on AQRVS 

in any particular situation. 

60 Hadson Power 14--Buena Vista, PSD Appeal Nos. 92-3, 92-4 

& 92-5 (Oct. 5, 1992). The EPA Environmental Appeals Board 

reasoned that, "States do not have unfettered discretion to 

reject an FLM's adverse impact determination. If a state 

determines that an FLM has not satisfactorily demonstrated an 

adverse impact on AQRVs from the proposed facility, the state 

must provide a 'rational basis' for such a conclusion, 'given the 

FLMs' affirmative responsibility and expertise regarding the 

Class I areas within their jurisdiction.' 50 FR 28549 (July 12, 

1985) . Arbitrary and capricious rejections of adverse impact 

demonstrations are not sustainable." [Hadson at p. 21. 

(citations omitted)] 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW * DOES NOT REPRESENT OFFICIAL EPA POLICY 

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The FIMQ are entrusted with administering the statutes 

governing the e^tratrlrfehmSnr and preservation of Federal Class I 

areas, and are expressly entrusted by the Clean Air Act- with an 

affirmative responsibility to protect th*s AQRV^of Federal 

-Glass I a^^ae-r The FLMs have expert knowledge about the uni^tie 

values associated with these -fctee lands they manage, and , ^ . 

administer ongoing ^"ograu'is of monitoring and research^en" 'fafaseffects that air pollution has on such values. Accordingly, the 

EPA believes it is appropriate for the permitting authority to 

give deference to recognize the FLM's oeientific and technical 

broad expertise in ita own evaluation of the FLM's dcmonotration 

the identification and evaluation of adverse effects on AQRVs. 

Ncvcrthclcoo,—the permitting authority io plainly given authority 

to determine whether to accept or reject the FLM'o dcmonotration, 

and it may reject the dcmonotration as long ao it haa a rational 

baoio for doing oo. Notwithstanding this expertise/ the 

permitting authority may call upon experts of its ot*n choosing to 

evaluate the findings in the FLM's demonstration. 

Where the permitting authority is not satisfied with the 

FLM's demonstration of adverse impact on AQUVs* T-the EPA is also 

proposing ||l|||a general consultation provision necessitating some 

form of communication and discussion between the permitting 

authority and the FLM when a dioagrccment arises; and (2)-: fn 

addition,—the EPA io proposing to a provision requireing the 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

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to the inherently fact-specific demonstration upon which an 

adverse impact on AQRVs is to be based. Thus, a notice may be 

filed (as described in section IV.C.I.e. of this preamble) 

alleging that a proposed source's emissions may cause or 

contribute to a change In the air quality in a Federal Class I 

area and Identifying the potential adverse impact of such change, 

flfcartdinc^.a-l-oney "Ihe fact that such source * s predicted ambient 

impact is less than the applicable significant impact level for 

Class I increments would neither relieve the applicant from 

having to complete an analysis of impacts on AQRVs nor 

automatically allow the permitting authority to reject the FLM's; 

demonstration of adverse impact on AQRVs, The EPA requests 

comments on its proposal to establish significant impact levels 

for Class I increments in general, and the proposed levels in 

particular. 

The EPA io declining to cotablioh oignificant impact Icvclo 

for fact bound>—oitc opecific AQRVo.—The FLM io cntruotcd with 

protecting AQRVo and the decioion to cotablioh any appropriate 

significant impact Icvclo for the AQRVo ohould root with the FLM. 

Any oignificant impact Icvclo for AQRVo may ncccooarily be aite ^N.^&2/-

gpecific since each AQRV and ito aooociated critical pollutant 

loadingo may be different from area to area and even within 

individual Federal Claoo I areao.— 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW * DOES NOT REPRESENT OFFICIAL EPA POLICY 

*** October 27, 1995 [file name: Master6.29R] *** 

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The EPA is declining to propose specific significance levels 

for determining whether the emissions from a proposed source may 

have an adverse impact on AQRVs. The FLM is specifically 

entrusted by the Act with protecting AQRVs and the decision to 

establish any appropriate significance levels for AQRVs should be 

made primarily by the FLMs. Conceptually, such significance 

levels would represent ambient air pollutant concentrations or 

deposition rates below which only de minimis effects on AQRVs 

will occur. Accordingly, emissions increases not resulting in 

ambient concentrations or deposition rates exceeding the 

prescribed significance levels would therefore be excluded from 

AQRV review. 

The EPA generally recognizes the administrative benefits of 

categorically eliminating certain pollutant-emitting activities 

from regulatory review and has employed significance levels in 

other contexts in the NSR program, including the significance 

levels proposed above for Class I increments. However, there are 

many obstacles to formulating reasonable significance levels in 

the AQRV context. For example, there are numerous AQRVs and 

there is a wide variance in sensitivity to emissions increases 

for particular AQRVs. 

The FLMs have been working with other air pollution effects 

scientists to develop lists of sensitive resources (e.g., species 

of plants and invertebrates, and particular streams and lakes) 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW * DOES NOT REPRESENT OFFICIAL EPA POLICY 

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and sensitivity thresholds that could help establish significant 

impact levels for individual AQRVs in the future. However, many 

studies conducted to date have not yielded the information needed 

to establish a critical threshold level from which a significance 

level could be derived. The EPA encourages the FLMs to continue 

pursuing research on AQRV effects, and anticipates an evolving 

process by which research and information may eventually support 

the establishment of site specific significance levels for 

individual AQRVs. \Site specific levels appear/ more feasible 

(UseAr 0 

since each AQRV and its associated critical pollutant loadings 

may be different from one area to another and even within 

individual Federal Class I areas.f In any event, EPA plans to 

establish an electronic database about Class I area resources, 

described elsewhere in this notice, that will make information 

about available research on AQRV effects more accessible. 

The EPA requests public comment on the issue of significance 

levels for AQRVs. In particular, EPA is interested in 

suggestions regarding alternative approaches that promote 

regulatory certainty by excluding from consideration proposed 

sources that have truly de minimis impacts on Class I resources 

while still ensuring that AQRVs are adequately protected in the 

PSD permitting process. Commenters should fully consider the 

legal standards that govern the establishment of de minimis 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

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*** October 27, 1995 [file name: Master6.29R] *** 
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regulatory exemptions. See e.g., Alabama Power Co. v. Costle. 

636 F. 2d 323, 360-61 (D.C. Cir. 1979) 

5. Clarification of Miscellaneous Issues. 

The discussion which follows addresses several relatively 

discrete issues. The EPA is clarifying current policy in areas 

where there is potential for significant confusion or uncertainty 

and, in some instances, is proposing conforming changes to the 

implementing regulations. The EPA is also proposing changes that 

largely codify existing policy. 

a. Significant Impact Levels for NAAQS and Class II and 

III Increments 

The EPA is proposing several changes to the PSD regulations 

at both section 51.166 and section 52.21 to make the rules 

consistent with current practice. First, the EPA is proposing to 

revise the provisions of existing section 51.166(k) and section 

52.21(k) to clarify that a source, itself, must make a 

"significant contribution" to a violation of any NAAQS or PSD 

Class II or III increment before that source would be denied a 

PSD permit. Second, the EPA is proposing to incorporate into the 

PSD regulations the significant impact levels currently set forth 

at section 51.165(b)(2)--which are being used to determine 

whether major new source or major modification contributes to a 

violation of a NAAQS--so that they may be directly applied to the 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW * DOES NOT REPRESENT OFFICIAL EPA POLICY 

*** October 27, 1995 [file name: Master6.29R] ***