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ppL UNITEDSTATESENVIRONMENTALPROTECTION AGENCY 

# ami OfficeofAir Quality Planning andStandards

r. ,z ResearchTrianglePark,NorthCarolina27711 

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# 91992

MEMORANDUM

SUBJECT: Public Hearing Requirements for 1990 Base-Year Emissions Inventories for Ozone- and Carbon Monoxide Nonattainment Areas

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. , FROM: John Calcagni, Directorrc- 

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Air Quality Management Division 

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~illiam G. Laxton, Director Technical Support Division

TO: Director, Air, Pesticides and Toxics Management Division, Regions I and IV Director, Air and Waste Management Division, Region I1 Director, Air, Radiation and Toxics Division, Region I11 Director, Air and Radiation Division, Region V Director, Air, Pesticides and Toxics ~ivision Region VI Director, Air and Toxics Division, Regions VII, VIII, IX, and X

It has come to the attention of the Office of Air Quality Planning and Standards that a number of States are confused about whether they need to follow the public hearing procedures for submittal of the emissions inventory. After several discussions with the Office of General Counsel, we believe that the emissions inventories are considered a part of the State implementation plan (SIP)under the amended CleanAir Act (Act)and, therefore,
are subject toa public hearing requirement at the State level. Thismemorandum provides guidance on how the States canmeet the requirement for public participation in the development of the 1990 base-year emissions inventories.
Traditionally, the States submitted their emissions inventories alongwith other elements of the SIP. In some instances, these inventoriesmay not have been considered as a part of the SIP. Although theprovisions of the amended Act do not refer tothe emissions inventory as a SIP revision, they do refer to it as a plan element and a plan provision [see sections 182 (a) (1)(A)and 172 (c)(3)

### 1. Therefore, the emissions inventory is a plan submittal that must be approved or disapproved under. section 110(k) and must meet the requirements of section110(a)(2), including the requirement that it was subject to a public hearing at the State level.

Moreover, we believe that there are policy reasons supporting the decision that the emissions inventory is to be approved into the SIP. The emissions inventorymust be used as the basis for the rate-of-progress plan for areas classified as moderate or above. Additionally, all nonattainment areas seeking redesignation to attainment will rely on an emissions inventory for purposes of submitting amaintenance plan under section 175(A). Because the emissions inventory plays such a fundamental role in determining the reductions necessary to attain and maintain the standard, it needs to receive full public scrutiny and be formally incorporated into the SIP.

However, because the regulatory consequences of the inventories are delayed, we have determined that it is appropriate toprovide a "de rninimisl8deferral of the State public hearing requirement up to such time as a public hearing is held on the related regulatory provisions. For areas classified
as moderate or above, the State would need to provide EPA with verification that a public hearing was held for the emissions inventory no later than the time the State submits the rate-ofprogress plan. For marginal areas, suchverification would be due when and if the State submits amaintenance plan for redesignation. However, to the extent amarginal area is "bumped-upwand, therefore, is required to submit a rate-ofprogress plan, the verificationwould be due as for moderate and above areas.
Since EPA is providing a "deminimis" deferral of thepublic hearing requirement, it is also appropriate to provide a "de minimist# deferral of the requirement for EPA to approve or disapprove such submittal within 12 months of the time EPA determines the submittal is complete. Therefore, EPA will publish the emissions inventories for public review after the November 15, 1992 submittal date, but EPA will defer section 110(k) approval action on the submittals until no later than the time at which they are submittedwith the rate-of-progress plan
or maintenance plan. Please note, however, that if the emissions inventory submittal does not otherwisemeet the completeness criteria (i.e., aside from the deferred public hearing requirement), 

### EPA may make a finding of incompleteness pursuant to sections 110(k)(1)and a79(a)(1). Such a findingwould trigger the 18-month sanction clock. A memorandum will be forthcomingwhich addresses issues on completeness determinations, parallel processing, and submittal of commitments.

This issue isnot relevant for carbon monoxide (CO) nonattainment areas, since CO areas with design values greater than 12.7 ppm must submit the entire SIP (emissionsinventories,attainment demonstrations, and control strategies)by November 15, 1992, and EPA expects the emissions inventories to have gone through the public hearing process as part of the full CO SIP. Emissions inventories for CO areaswith design values of 12.7 ppm and below have no regulatory impacts at the time of the November 15, 1992 submittals. Like margi~al ozone areas, CO
areaswith design values 12.7 ppm and below would be required to subject the emissions inventory to thepublic hearing and adoptionprocess if the area attains the CO NAAQS and 'subsequentlydevelops a redesignation request and associated maintenance plan, or if the area fails to attain the standard by December 31, 1995 and is reclassified to serious and therefore required to submit an attainment plan.

Certain concernshave been raised regarding this interpretation. First, someRegions believe that imposing the public hearing requirement so late in theprocess will have the ramificationof delaying the submittal of the 1990base-year emissions inventoriesby asmuch as 18 months. Such a delay would in turn delay the development of the 15 percent plans and the full SIP'S. Therefore, the above proposal allows submission of the emissions inventoriesprior to thepublic hearing process. States would then complete thepublic hearing and adoption process on the emissions inventoryprior to the submittal of the rate-of-progress plans on November 15, 1993 because this is the point at which these emissions inventoriestake on regulatory status. This approachwould not create significant delays in the emissions inventory and SIP development process and would allow a reasonable time for the States to complete thepublic hearing and adoption process. Under this approach,-EPAcould parallel process the emissions inventories, proposing approval of the inventories, and providing that final approvalwill not occur until the States revise the inventoriesto addresspublic comments. In fact, we encourage ~egional offices toparallel process the emissions inventories for moderate and above ozone areas which are developing their rate-of-progress plan and for any ozone or CO area seeking to redesignate to attainment.

Several Regionshave raised additional concerns with the requirement that the emissions inventorybe approved into the SIP. One such concern is that the emissions inventorywill be subject to

### a significant amount of questioning concerning the details, assumptions, and calculationmethods. Although thismay be true, we believe that it is a necessary result. As previously stated, the emissions inventorywill be the basis for control measures, trading, banking and otherAct programs. Therefore, the public should have an opportunity to closely scrutinize the inventory before the Statedevelops and implements those aspects of its SIP.

A thirdmajor concern is subsequent revisions to the emissions inventories and theneed to go through the SIP revisionprocess. 

### We recognize that in certain cases, a fewmajor changes
or numerous minor changes to the emissions inventory will impact the 15 percent reduction calculation and will thus require a revision to-thecontrol strategy. In such cases, all changes could be bundled together into one SIP revision. However, we also recognize that certain changes will not impact the 15 percent reduction calculation, the control strategy, or the maintenance plan showing. We believe it is appropriate to create
a Hdeminimisn exception to the public hearing requirement for minor changes. We also think it is appropriate for EPA totrack these ride minimisn changes and record them. Such changes could then be handled through a letter notice or a direct final action. We define ride minimisn for such purposes tobe those inwhich the 15 percent reduction calculation and associated control strategy,
or themaintenance plan showing, do not change. We expect a State to aggregate all such "deminimisn changes togetherwhen making the determination as towhether the change needs tobecome a SIP revision. At thepoint when all such ride minimismchanges, aggregated together, impact the 15 percent reduction calculation
ormaintenance plan showing, then all changes need tobe submitted as a SIP revision, alongwith any associated control strategy changes. When approving the initial emissions inventory into the SIP, theRegion should also provide notice that "de minimisn changes temporarily will be made through letternotice. Headquarters will develop boilerplate language for insertion into thesepackages. At the time when an EPA ~egion believes that several mdeminimisn changes together impact 

### a controlmeasure or other program, the Statewill then need tomake the change through a formal SIP revision process, in conjunction with the change to the controlmeasure or other SIP program.

We trust that this information will be of help toyou 

### as you guide your States through the SIP development process. Ifyou have questions or comments, please contact Sheila Holman (919- 541-0861) or David Misenheimer (919-541-5473).

1 cc: J. Seitz L. Wegman RegionalAir Branch Chiefs

bcc: T. Helm 

### B. Nicholson D. Mobley D. Misenheimer S.. HO~M~ S. Nizich <,.3 M. Martinez M. Wolcott
x. N. Dobie r ' R. Ossias J. Tierney Regional SIP EI Section Chiefs Regional Ozone 

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