p.1 

OAR Box 1793 

Prepped by Keeia Richards 

Document Number: 

18) ll-F-60 

Docket Number: 

A-90-37 

Printed 11/3/2008 11:31:54 AM Sheet 18 of 45 
P.2 

•»^s 

. A-tO-3-7 

****** tovknmwto o^fcf£r 

Pffice of Air Q ^

 Wannjng ^ sJ^n 

U. S. Environmental Protection Agency , ~ 

Research Triangle Park, NC 277U ^ 

FAX Number: (919)541-5509 

FAX TRANSMISSION 

TO: 

DfAMB 

Datr. /^s_w/V 

lOOMFANY/OFFICfi "* " ' ^ 

QMS 

VHONB NUMBER' 

FROM: 

c

-

c

-

:

 -£>eu^ CaS-iccQ&Qg 

|FAX NUMBER 

xVgjo/jss C&UMP/.^£-

7.0 2. -A5ZCmm. j /$£ 

pHONBNUM_U_R 

919-341- <3^? / 

COMMENTS: 

i—— — 

^ %Ans OAAsi 

. g o CUSISA&T^J. a**,/ y66^r C&K/IVZ+JZS &?, V/9 ' 

*W /<?/r" 

Number of Pages (including cover sheet): ^Pp^^ ' a 

If you did not receive all the pages, please contact the following person; 

P

3 3

 fSowNuiaB — 

L •'• • I 919.341. 
P.3 

The Applicability Subgroup of the CAAAC's NSR Reform pt 1? 9 , 

Subcommittee considered many applicability options. While none 

of these proposals garnered the full Subcommittee's support, 

representatives of State and local regulators as well as 

environmental groups expressed general support for the idea that 

"benign" changes at existing emissions units do not need to 

undergo thc actual to potential test should not be subject to andthe complicated NSR netting applicability rules in every inotancc 

rela.ed to «-_•__ « a silica* , - e anion s ___«_«,. ^ 

There was also support for the proposition that the NSR ** 

applicability test should provide some deference to sources that 

have already undergone major NSR. 

The EPA, after careful consideration of these discussions, 

believes that the best approach for a new exclusion is one that 

focuses on the existing emissions control of a unit, rather than 

the change being proposed. Almost all stakeholders identified 

the goal of ensuring that modified units apply state-of-the-art 

controls as being of paramount importance. Accordingly, where an 

emissions unit already meets this goal, environmental concerns 

associated with proposed changes are likely reduced. For 

example, it is the EPA's experience that in many cases where an 

existing well-controlled unit triggers major NSR, the permitting 

process does not necessarily result in improved controls. On the 

other hand, where the review is focused on units which have not 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW * DOES NOT REPRESENT OFFICIAL EPA POLICY 

***October 25, 1995 [file name: Master9.17] *** 
P.4 

29 

recently been required to meet a control technology requirement, 

NSR can be expected to result in more otringcnt effective *" £^ 

controls and meaningful reductions in actual emissions. 

Similarly, where an entire facility already meets the goal 

of the application of state-of-the-art controls and has undergone 

an air quality impact analysis of its emissions, environmental 

concerns associated with proposed changes are likely reduced if 

the changes remain consistent with requirements imposed by the 

p||||m|^ analysis. Thus, EPA is also proposing a "clean", 

facility exclusion that allows a major stationary source to make 

changes at its facility consistent with PSD or NSR permits that 

have been recently issued. 

2. Description of the Clean Unit Proposal 

Based on these factors, the EPA is today proposing a 

simplified applicability test for changes to existing emissions 

units that already are well-control led considering the extent a per 

Jyfo& 

current BACT/LAER review for a particular unit would result in r .<-%*. 

lower emissions have otato of the art cmiooion controls. In ,~ £_.*» ~ 

general, this new "clean unit" exclusion will allow States to %<** 

exclude from major NSR, proposed changes to existing emissions 

units that have installed major BACT or LAER within the last 10 o/U 

years or which otherwise qualify as a "clean unit." Under this 

exclusion, sources can make any change to a qualifying unit so 

long as the change will not increase the unit's emissions rate 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW * DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] •*• 
P.5 

30 

(measured in terms of the unit's maximum hourly emissions, the 

new source performance standard (NSPS) test found at existing 

40 CFR 60.14) . Specifically, changes which do not increase the 

unit's hourly potential emissions would not be considered a 

physical or operational change and thus would not trigger major 

NSR.9 See proposed sections 51.165(a)(1)(v)(C)(i£), 

51.166(b) (2) (iii) (L) and 52.21(b) (2) (iii) (L) . 

The proposed "clean unit" exclusion would both simplify the 

applicability test for qualifying units and increase source 

flexibility. It would also reward sources that in the recent a r 

past have applied otringcnt controls to their emissions units ' Atf* 

that were equal o r comparable to B&CT or LAER. «*$, ^ T i°l ^ 

<9*r ' 

Ideally, the change in hourly potential emissions would be 

assessed immediately before and after the change"to determine if 

9 Under today's proposal, for units that are permitted to 

change feedstocks frequently, such as pharmaceutical 

manufacturing and certain chemical batch processes, the maximum 

hourly emissions rate test would be applied on a per feedstock 

basis to determine if an emission increase will occur. For 

example, a unit which has state-of-the-art VOC control technology 

and uses toluene and other organic solvents as feedstocks, the 

hourly maximum emission rate of toluene before and after the 

proposed physical or operational change would be assessed as if 

toluene alone was to be fully utilized by the unit before and 

after the proposed change. The other feedstocks would also be 

individually assessed. A change in feedstock would not trigger 

NSR if the control technology designed to control emissions 

resulting from the feedstock and the unit was previously 

permitted to use the feedstock. The EPA encourages suggestions 

in developing rules or guidance on other approaches for 

determining emissions increases for processes with rapidly 

changing and mixed feedstocks. 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 --- [file name: Master9.17] ••• 
P.6 

31 

an emissions increase did indeed occur. However, this may not be 

practical in many instances because information necessary to 

establish the hourly potential emissions rate may require 

considerable time to develop or collect. Therefore, under the 

proposed provision, the pre-change hourly potential emission rate 

may be established or verified at any time up to 6 months prior 

to the proposed activity or project. The EPA solicits comment on 

alternative periods for establishing the pre-change hourly 

emissions rate, particularly periods which might allow the use of 

routine compliance emissions tests to determine the emissions 

rate (e.g., annual). Also under the proposed provision, where 

the unit is subject to a federally enforceable limit on 

operations or emissions which limits the unit's hourly potential 

emissions to less than the maximum, physically achievable hourly 

rate, the unit's lower allowable rate must be used in determining 

if an emissions increase will occur at the unit. 

3. What Constitutes a "Clean Unit" 

For this exclusion to function, it is necessary to 

distinguish a well-controlled unit from a poorly controlled one. 

In other words, what criteria distinguish a unit eligible for 

this exclusion from one which is not? Criteria which allow a 

broad range of units to qualify could largely transform the 

existing applicability system into one based solely on assessing 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 
P.7 

32 

a unit's potential emissions, with the possibility of a dramatic 

increase in a unit's actual emissions without undergoing NSR. 

The EPA-^-s proposes to require emissions units to have a 

"federally enforceable emissions limit" that "is comparable to 

the emission limit that . . . would result from a current review" 

of that particular unit under the BACT or LAER requirements, 

whichever is applicable to the proposed change. (See, e.g.. 

proposed sections 51.165(a) (1) (v) (C) (ifi).(ii.) , 

51.166(b) (2) (iii) (L) (2) and 52.21(b) (2) (iii) (L) (2) .) TheEPA 

envisions that three types of limits would qualify: (1) BACT or 

LAER limits set within the last 10 years for the particular unit; " 

(2) | limits set within the last 10 years* for the particular unit 

by a State technology review program determined by EPA to be 

equivalent comparable to the federal BACT or LAER programs; and 

(3) ii limits- found on a case-by-case basis -- after notice and 

opportunity for public comment -- to be equivalent comparable to 

the current BACT or LAER limits that would otherwise be imposed la 

on the source after weighing the cost and benefits of additional « JQJ 

or modified oontrols, including retrofit cost and benefits. 

a. Units with BACT or LAER Limits 

One starting point for determining whether a unit is wellcontrolled is the level of control required to satisfy BACT (in 

attainment/unclassified areas) or LAER (in nonattainment areas). 

For units which have recently undergone these reviews, rePRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 
P.8 

33 

evaluation of the technology shortly after the source is 

constructed or modified to determine if the technology is still 

"state-of-the-art" would likely result in very little or no 

incremental improvement in emissions control. Moreover, units 

that are recently permitted are far less likely to have 

physically deteriorated and more likely to be running near 

permitted capacity, reducing the risk that changes to the unit 

will result in increased utilization and increased actual 

emissions. 

Therefore, the EPA is proposing that the new exclusion may 

presumptively apply to any unit which received a BACT or LAER 

limit in a currently applicable major NSR permit within 10 years 

of the proposed change under consideration. See proposed 

sections 51.16.5(a) (1) (v) (C) (1£) (vj (1) , 51.166(b) (2) (iii) (L) (5.) (i) 

and 52.21(b) (2) (iii) (L) (5.) (i) . In other words, for the first 10 

years following issuance of a PSD or nonattainment NSR permit, 

units subject to BACT or LAER set in that permit are eligible for 

the clean unit exclusion. At least some members of the 

Subcommittee expressed concern that the ten year period is too 

long given the improvement in control technology that can occur 

in some source categories. For this reason, EPA solicits comment 

on using a shorter period such as five years as the length of the 

Clean Unit presumption derived from a NSR permit. 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW * DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 
P.9 

34 

During consideration of the Clean Unit Exclusion, several 

participants suggested that units subject to maximum achievable 

control technology (MACT) or reasonably achievable available \^A 

control technology (RACT) should also automatically qualify as 

clean units. A recently required MACT emissions limit, while not 

necessarily equal to BACT or LAER, is likely to result in 

significant emissions controls such that a BACT or LAER review 

would not necessarily result in significant additional emissions 

reductions. However, the EPA is also concerned that a MACT limit 

could be significantly less effective in limiting volatile 

organic compound (VOC) emissions than BACT or LAER in many 

circumstances. A MACT emission limit may adequately control a 

toxic VOC but could result in emission increases of pollutants 

subject to NSR. For example, an incinerator installed to reduce 

a toxic VOC will increase nitrogen oxides (NOx) emissions emitted 

to the atmosphere. 

The EPA also has concerns with using Federal RACT limits to 

presumptively qualify a unit as a clean unit-:—In nonattainment 

areas, A since RACT emission limit! io almoot alwayo much can be 

less stringent than current LAER and BACT-T—in the EPA' a view, £*»<-; 

often would be logo stringent than a BACT limit. Further, in ^ i" 

some instances RACT is based on the attainment needs of the area 

and not a specific control technology standard. While EPA 

solicits comment on presumptively applying the clean unit 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 
P.10 

35 

exclusion test to units with Federal MACT or RACT limits, the EPA 

is not-inclined to do so across the board. Rather, the EPA 

believes that MACT or RACT limits should be found to qualify for 

the Clean Unit exclusion using the case-by-case option described 

in section II.C.3.C below. 

b. State Technology Programs Equivalent Comparable to BACT or 

LAER 

There are many emissions units at stationary sources that 

were permitted according to a State's minor NSR permitting 

program. While these units are H^l not controlled pursuant *}/£} 

subject to a major source BACT or LAER limit per se, they still a* 

may have installed state of thc art controls that would'have 

satisfied major source BACT or LAER requirements at the time the 

permit was issued* For instance, several jurisdictions have 

control technology reviews as part of State, local or tribal 

minor NSR program which requires new or modifying sources to meet 

emissions levels equivalent comparable to major source control 

technology requirements (BACT or LAER). For this reason, the EPA 

is proposing that permitting authorities may submit minor NSR 

control technology requirements for certification by the EPA that 

the minor NSR program requires control technology that would 

satisfy the requirements for the clean unit exclusion. See 

proposed sections 51.165(a)(1)(v)(C)(10)(v)(1), 

51.166(b) (2) (iii) (L) (5) (ii) and 52.21(b) (2) (iii) (L) (5_) (ii) . Once 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 
P.11 

36 

determined by EPA to be equivalent comparable, all units subject 

to emissions limitation established under the jurisdiction's 

minor NSR program would be eligible for the Clean Unit exclusion 

for the first 10 years following issuance of the permit. This 

could also apply to permits that have been issued previously 

under minor NSR technology requirements that are later determine^ .^f 

to be comparable to major source BACT or LAER requirements. In §Oe / 

such a case, the clean unit exclusion apply to the unit with the ** Q\£ 

(fr* 

minor NSR permit, but it would take ef feet* once BPA amkes the 

if" 

certification of comparability {i.e., the clean unit test would 

not apply to modifications that haves occurred prior to the 

certification) • Tne clean unit test could apply to the qulifying 

unit for ten years after issuance of the minor source permit. 

The EPA also solicits comment on whether a shorter period, such 

as 5 years, would be more appropriate. 

The EPA also solicits comment on the appropriate standards 

for EPA to use in determining whether a permitting authority's 

minor NSR program control technology requirements are comparable 

to the BACT and LAER requirements. The EPA envisions that as a 

minimum a "pre-certified" minor NSR program comply with 40 CFR 

51.160-164.10 

c. Qualification of Units on a Case-By-Case Basis 

10In a separate rulemaking EPA is revising the public review and comment 

requirements to give more States more flexibility in dealing with minor source 

permits. See FR 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 
P.12 

37 

In many cases an emissions unit not subject to major NSR is 

constructed or retrofitted with a control technology or strategy 

equivalent comparable to the best controls applied in practice. 

This may occur when a source minimizes emissions in order to 

"net" a unit out of major NSR or applies controls to comply with 

other provisions of the Act. For this reason, the EPA's proposed 

regulations would allow a source having a limit on an emissions 

unit determined to be equivalent comparable to BACT or LAER for 

the particular unit considering cost and benefits of additional 

or modified controls, including retrofit cost and benefits to 

qualify for the "clean unit" exclusion on a case-by-case basis. 

Specifically, an existing unit which has not undergone a BACT or 

LAER determination or comparable State technology requirement can 

also qualify as a "clean unit* if, in the informed judgment of 

the permitting agency, a current 8&CT or LAS& determination for 

the unit would not be expected to result in any lower level of ^ -^ 

emissions from the unit for the pollutant in question. The costs, ^A / jr 'i A. 

benefits and technical consideration associated the retrofit «• 

application of additional controls to the particular unit may be 

considered by the permitting agency in the evaluation. Since 

this in effect may require the permitting authority tc engage in 

a technology review that is similar BACT or LAER review in order 

to qualify a unit for this exclusion, the EPA is asking for 

comment on other approaches for qualifying units. 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 

A* 
P.13 

T* Ar-tr fc«-S /0-# "i/*-

38 

Once a permitting authority makes this determination through 

a process involving notice and opportunity for public comment, 

the unit would be eligible for the clean unit exclusion for the 

next five years. As with the other types of proposed clean unit 

exclusions, EPA requests public comments on the proposed 

exclusion eligibility period. See proposed sections 

51.165(a) (1) (v) (C) (10) (y) (3), 51.166(b) (2) (iii) (L) (5) (iii) and 

52.21(b)(2)(iii)(L)(5)(iii). 

The EPA proposes solicits comments on several other ^\ ^ ^ 

alternative bases upon which a permitting authority could take to 

make the determination that a unit has an equivalent ^^|^r§ip^ 

BACT or LAER emissions limitation. The first would be based on 

an average of BACT or LAER for equivalent or similar sources over 

a recent period of time (e.g., most recent three years). The 

second would be based on the unit's control level being within 

some percentage (e.g., five or ten percent) of the most recent, 

or average of the most recent, BACT or LAER levels for equivalent 

or similar sources. The EPA solicits comment on these approaches 

and on the general issues concerning whether and how EPA should 

impose a specific methodology for determining that a specific 

emissions limit is "comparable" to the current BACT or LAER limit 

that would result from a review. 

For all of thc above tests,—thc EPA rcaligoo that there aro /)ft0 

many source and omission unit catcgorico for which BACT or LAER */_ 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND ^ 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY «/• 

•••October 25, 1995 --- [file name: Master9.17] ••* "/o 
P.14 

39 

dctcrminationo do not cxiot,—let alone recent determinations. 

For thcae oourcco,—the EPA proposes that their level of control £/"•« 

be gauged against the control level associated with BACT or LAER /|^ 

for emission units with similar cmiooion stream characteristics p/e 

That io,—if the omiooiono unit were to undergo a BACT or LAER fayf* 

Lo 

review today or recently, what tcchnologico would be evaluated 

and what arc the current BACT or LAER lcvclo associated with 

thooc tcchnologico? Since thio in effect rcquiroo tho permitting 

authority to engage in a BACT or LAER review in order to qualify 

a unit for thio cxcluaion,—thc EPA io aoking for comment on other 

approachco for qualifying unito. 

States are encouraged to use the permitting process required 

by title V of the Act as the vehicle for determining and 

recording which units at a title V source can qualify for this 

exclusion.11 The permitting authority could use the title V 

permit issuance, revision or renewal process as the mechanism for 

making the case-by-case determination (so long as the opportunity 

.*** 

11 While rules implementing title V address how the unit's 

major NSR permit and BACT or LAER limit are incorporated into the 

title V permit, it is not clear that the status of a unit as a 

NSR clean unit would be included in the title V permit as an 

applicable requirement. Whether the status of a unit as a NSR 

clean unit presumption is an applicable requirement in the title 

V permit will likely depend upon how the clean unit test is 

adopted by the permitting authority (e.g., adopted as a SIP 

requirement). The EPA solicits comment on the best approach for 

implementing and coordinating the review and designation of clean 

units with the title V permit process. 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 
P.15 

40 

for public comment is provided). For convenience, one, many or 

all units at a source could be reviewed and subjected to public 

notice and comment concurrently with the issuance or renewal of a 

title V operating permit. For units eligible for the "clean 

unit" exclusion due to a prior NSR BACT or LAER determination, or 

a determination under a program found comparable by EPA, the 

title V permit offers the opportunity to clearly set forth the 

status of the unit under the Clean Unit exclusion. Qualifying 

clean units and the pollutant for which the determination was 

made should be clearly identified and listed in the title V 

permit as "clean units" for NSR purposes. 

Under today's proposal, a unit that does not initially 

qualify for the clean unit exclusion could install controls 

meeting the criteria the EPA establishes for well-controlled 

units and thereby qualify to use the exclusion. The controls or 

pollution reduction strategy that are the basis for the clean 

unit determination must be in place and federally enforceable at 

the time the source relies on an exclusion under this provision. 

So long as these federally enforceable conditions are met, the 

source is free to make any change at the permitted unit including 

those which could affect a unit's efficiency, capacity, 

availability, longevity and utilization. However, changes which 

would bring into queotion cl_l||iiiiiil the original emissions £•' 

unit's BACT or LAER control level or air quality impact (e.g., /^ 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 
P.16 

41 

modified stack parameters which would cause or contribute to 

violation of any applicable ambient standard, replacement of the 

unit with a different type or size of unit, or reconstruction of 

the unit) would not be allowed. Also, for units excluded from 

major NSR under this proposed revision, the physical or 

operational change must still comply with all otherwise 

applicable Clean Air Act and SIP requirements including any 

federally enforceable limits on emissions or operations and minor 

NSR requirements. 

Finally, the determination that a unit is "clean" or "wellcontrolled" under today's proposal is an applicability test and 

is independent from the case-by-case determination of BACT or 

LAER for sources subject to major NSR. While control technology «\s 

which qualifies a unit as "clean" may be * comparable" to BACT oro w,

e'5 

LAER for a particular unit considering its unique circumstances, 

it is not necessarily equal to BACT or LAER for that unit when 

considered as part of a new major facility or major modification, 

and in no way establishes a presumptive BACT or LAER for that 

unit, source type or category. Further, a five or ten year 

presumption that a unit is "clean" does not in any way "freeze" 

BACT or LAER determinations in permitting actions. The Act 

requires that BACT and LAER be current caoc by case 

determinations for sources subject to major NSR and the clean 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 
P.17 

42 

unit toot designation cannot Hlii!ili override this requirement 

determination. ^^ t.[i1%^/^ 

4. Description of the Clean Facility Proposal ° 

f^e^rJcS 

Similar to the clean unit exclusion, EPA is proposing an 

exclusion for changes at clean facilities. This "clean facility" 

exclusion will allow States to exclude from major NSR proposed 

changes to an existing major stationary source that has installed 

major BACT or LAER and has undergone an air quality impact 

analysis as appropriate to the area designation, or which 

otherwise qualify as a "clean facility." See proposed sections 

51.165(a)(1)(v)(C)(11), 51.166(b)(2)(iii)(M) and 

52.21(b)(2)(iii)(M). Under this exclusion, sources can make any 

change to the major stationary source that is consistent with the 

PSD or NSR permit. The EPA envisions this to allow changes that 

do not include adding new units or allowing emissions trades that 

were not evaluated for air quality impacts in the NSR or PSD 

permit. The exclusion would allow, however, source to replace or 

reconstruct existing units so long as they continue to meet the 

control technology and emissions requirements established in the 

permit. Thus, such replacement or reconstruction would not 

result in a different type of unit than envisioned and covered by 

the PSD or NSR permit and its requirements. 

The EPA requests comments on this proposal and whether the 

determination of "clean" facility should be more stringent or 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 
P.18 

43 

similar to the "clean" unit. The EPA is proposing that the 

qualification for this exclusion be similar to that under the 

clean unit exclusion. As proposed, a clean major stationary 

source is one that underwent NSR within the last 10 years. EPA 

also requests comment on whether this proposal should not allow 

units or facilities to be replaced or reconstructed. Certainly, 

The addifte/ition of new lilllllil units not covered by the £*' " 

existing permit would not be permitted allowed under the «//7 

proposal. bccauoc ouch changco would not be conoiotcnt with thc 

cxioting NSR permit. Similarly, emissions trades may not be 

permissible where an different air quality impact would result 

since the PSD or NSR permit might limit such differing impacts. 

D. Revision to the Netting Baseline 

Today's notice describes and solicits comment on a new 

method for determining an existing source's baseline emissions 

for purposes of determining whether a physical or operational 

change will cause an increase in emissions and trigger NSR. 

1. Introduction 

As discussed, in order to determine whether a physical or 

operational change will result in an increase in emissions, it is 

necessary to compare a source's emissions before the change (its 

baseline emissions) with its emissions after the change. The 

EPA's existing regulations generally define baseline actual 

emissions as "the average rate, in tons per year, at which the 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••* 
42 

unit teat designation cannot does not override this requirement j 

determination. ^ |6> s

 c k ^ V L 

4. Description of the Clean Facility Proposal y . V/"r \ajov A , 

Similar to the clean unit exclusion, EPA is proposing an* Xty*"^ 

exclusion for changes at clean facilities. This "clean facility" 

exclusion will allow States to exclude from major NSR, proposed 

changes to an existing major stationary source that has undergone 

major NSR for the entire source within the last 10 years. 

inotallcd major BACT or LAER and haa undergone an air quality 

impact analysio ao appropriate to thc area dcaignation,—or which 

othcrwioc qualify ao a "clean facility." See proposed sections 

51.165(a) (1) (v) (C) (11), 51.166(b) (2) (iii) (M) and 

52.21(b) (2) (iii) (M) . Under this exclusion, a major sources can 

make any change as long as the source would still be|l|| 

compliance with its major $SR permit, to thc major otationary 

oourcc that io conoiatcnt with thc PSD or NSR permit.— The EPA 

envisions this to allow any changes that do not include adding 

new units or allowing emissions trades that were not evaluated 

for air quality impacts in the major NSR or PSD permit. The 

exclusion would,however, allow however | source to replace or 

reconstruct existing units so long as they continue to meet the 

control technology and emissions limitations rcquiremento 

established in the permit. Thus, such replacement or 

reconstruction would not result in a different type of emissions 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] ••• 
P.20 

43 

unit than envisioned and covered by the PSD or major NSR permit 

and its requirements. The addition of new emissions units would 

not be allowed under the proposal because such changes would not 

be consistent with the existing NSR permit. However, all other 

changes consistent with the terms of the major HSR permit would 

not be considered a "physical or operational change" for the 

purposes of major NSR applicability. Similarly. emissions trades 

may not be permissible where an different air quality impact 

would result since the PSD or NSR permit might limit such 

differing impacts, 

Tho EPA roqucoto commcnta on thio propoaal and whether thc 

determination of—"clean"—facility ahould be more otringcnt or 

aimilar to thc "clean" unit. Thc EPA io propooing that thc 

qualification for thio cxcluoion be oimilar to that under thc 

clean unit excluoion. Ao propoocd,—a clean major otationary 

oourcc io one that underwent NSR within the laot 10 years. EPA 

aloo requests comment on this approach and specifically on 

whether this proposed ai approach should not allow units or 

facilities to be replaced or reconstructed. Certainly,—adding 

new unito would not be permitted under the propoaal bocauac auch 

changca would not be conoiatcnt with thc cxiating NSR permit. 

However,—all other changco conaiotcnt with thc tcrmo of thc major 

NSR permit would not be conoidcrcd a "phyoical or ope rational 

change"—for thc purpooco of major NSR applicability. Similarly, 

PRELIMINARY STAFF WORKING DRAFT FOR OFFICE OF MANAGEMENT AND 

BUDGET REVIEW • DOES NOT REPRESENT OFFICIAL EPA POLICY 

•••October 25, 1995 [file name: Master9.17] •••