>*,*to S'4P ,.' ppL UNITED STATES ENVIRONMENTAL PROTECTION AGENCY ami Office of Air Quality Planning and Standards 

r. ,z 

Research Triangle Park, North Carolina 2771 1 

SEP 2 9 1992 

MEMORANDUM 

SUBJECT: Public Hearing Requirements for 1990 Base-Year 

Emissions Inventories for Ozone- and Carbon Monoxide 

Nonattainment Areas ,. /' < ,' . , 

FROM: John Calcagni, Directorrc- 2;,#. " - 

Air Quality Management Division \ 1 

~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 Clean Air Act (Act) and, therefore, 

are subject to a public hearing requirement at the State level. 

This memorandum provides guidance on how the States can meet the 

requirement for public participation in the development of the 

1990 base-year emissions inventories. 

Traditionally, the States submitted their emissions 

inventories along with other elements of the SIP. In some 

instances, these inventories may not have been considered as a 

part of the SIP. Although the provisions of the amended Act do 

not refer to the 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 section 
110(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 inventory must 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 a maintenance 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 to provide a "de rninimisl8 deferral 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, such verification would be 

due when and if the State submits a maintenance plan for 

redesignation. However, to the extent a marginal area is 

"bumped-upw and, therefore, is required to submit a rate-ofprogress plan, the verification would be due as for moderate and 

above areas. 

Since EPA is providing a "de minimis" deferral of the public 

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 submitted with the rate-of-progress plan 

or maintenance plan. Please note, however, that if the emissions 

inventory submittal does not otherwise meet 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 finding would 

trigger the 18-month sanction clock. A memorandum will be 

forthcoming which addresses issues on completeness 

determinations, parallel processing, and submittal of 

commitments. 

This issue is not relevant for carbon monoxide (CO) 

nonattainment areas, since CO areas with design values greater 

than 12.7 ppm must submit the entire SIP (emissions inventories, 
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 areas with 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 

areas with design values 12.7 ppm and below would be required to 

subject the emissions inventory to the public hearing and 

adoption process if the area attains the CO NAAQS and 

'subsequently develops 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 concerns have been raised regarding this 

interpretation. First, some Regions believe that imposing the 

public hearing requirement so late in the process will have the 

ramification of delaying the submittal of the 1990 base-year 

emissions inventories by as much 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 inventories prior to the public hearing process. 

States would then complete the public hearing and adoption 

process on the emissions inventory prior to the submittal of the 

rate-of-progress plans on November 15, 1993 because this is the 

point at which these emissions inventories take on regulatory 

status. This approach would not create significant delays in the 

emissions inventory and SIP development process and would allow a 

reasonable time for the States to complete the public hearing and 

adoption process. Under this approach,-EPA could parallel 

process the emissions inventories, proposing approval of the 

inventories, and providing that final approval will not occur 

until the States revise the inventories to address public 

comments. In fact, we encourage ~egional offices to parallel 

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 Regions have raised additional concerns with the 

requirement that the emissions inventory be approved into the 

SIP. One such concern is that the emissions inventory will be 

subject to a significant amount of questioning concerning the 

details, assumptions, and calculation methods. Although this may 

be true, we believe that it is a necessary result. As previously 

stated, the emissions inventory will be the basis for control 

measures, trading, banking and other Act programs. Therefore, 

the public should have an opportunity to closely scrutinize the 

inventory before the State develops and implements those aspects 

of its SIP. 

A third major concern is subsequent revisions to the 

emissions inventories and the need to go through the SIP revision 
process. We recognize that in certain cases, a few major changes 

or numerous minor changes to the emissions inventory will impact 

the 15 percent reduction calculation and will thus require a 

revision to-the control 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 Hde minimisn exception to the public hearing requirement for 

minor changes. We also think it is appropriate for EPA to track 

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 to be those in which the 

15 percent reduction calculation and associated control strategy, 

or the maintenance plan showing, do not change. We expect a 

State to aggregate all such "de minimisn changes together when 

making the determination as to whether the change needs to become 

a SIP revision. At the point when all such ride minimism changes, 

aggregated together, impact the 15 percent reduction calculation 

or maintenance plan showing, then all changes need to be 

submitted as a SIP revision, along with any associated control 

strategy changes. When approving the initial emissions inventory 

into the SIP, the Region should also provide notice that "de 

minimisn changes temporarily will be made through letter notice. 

Headquarters will develop boilerplate language for insertion into 

these packages. At the time when an EPA ~egion believes that 

several mde minimisn changes together impact a control measure or 

other program, the State will then need to make the change 

through a formal SIP revision process, in conjunction with the 

change to the control measure or other SIP program. 

We trust that this information will be of help to you as you 

guide your States through the SIP development process. If you 

have questions or comments, please contact Sheila Holman (919- 

541-0861) or David Misenheimer (919-541-5473). 

1 

cc: J. Seitz 

L. Wegman 

Regional Air 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 / CO SIP EI CONTACTS