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OAR Box 1787 

Prepped by Ollie Stewart 

Document Number: 

32) II-B-17 

Docket Number: 

A-90-37 

Printed 11/4/200810:22:19 AM Sheet 32 of 147 
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

Office of Air Quality Planning and Standards 

Research Triangle Park, North Carolina 27711 

JUL 2 8 1983 ft -</d'31 

MEMORANDUM 

SUBJECT: Supplemental Guidance on Implementing the North County 

Prevention of Significant Deterioration, (PSD) R^ma^d,^-; 

FROM: 

1/ (1 Y K i'i ' i 

John Calcagni, Director /u^J I^Jt'^^Ukiy ~ 

Air Quality Management Division (MD-15) /) 

TO: I Addressees 

On September 22, 1987, Gerald Emison issued guidance on implementation 

of the Administrator's remand decision in the North County PSD permit appeal, 

PSD Appeal No. 85-2. That document sets forth, in general terms, the essence 

of the remand--that al l pollutants, including those not directly regulated by 

the Clean Air Act are to be considered in making the best available control 

technology (BACT) determination for a PSD applicant. Now that the guidance 

is out, various issues beyond the scope of the September 22, 1987 document 

have arisen. I am addressing two of them. The firs t deals with the flexibilit y 

that the permitting authority has with respect to pollutants considered and 

controls selected, while the second involves the level of detail needed in 

the PSD public notice. 

Consideration of Air Toxics in the BACT Determination 

The BACT requirement is implemented through case-by-case decisionmaking. 

While this necessarily involves significant use of judgment by the permitting 

authority, certain policy presumptions apply: that i t consider the ful l range 

of pollution control options available and choose the most effective means of 

limiting emissions, subject only to a showing of compelling reasons of economic 

or energy impracticality. Those are the important lessons underscored by the 

North County and H-Power remands. The presumption of employing a top-down 

BACT analysis was further emphasized in Craig Potter's memorandum of December 

1, 1987, entitled "Improving New Source Review (NSR) Implementation," to the 

Regional Administrators. Other policy presumptions were articulated in the 

September 22, 1987 guidance requiring that the BACT determination for regulated 

pollutants be sensitized to the control of unregulated air pollutants (including 

air toxics). 

The September 22, 1987 policy does not identify which toxic substances, 

require consideration in the BACT analysis, and at what levels. Among the 

reasons for this is that the information with respect to the type and magnitude 

of emissions of noncriteria pollutants for many source categories is limited. 
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For example, a combustion source emits hundreds of substances, but knowledge 

of the magnitude of some of these emissions or the hazard they produce is 

sparse. While the Environmental Protection Agency (EPA) is pursuing a variety 

of projects that will help permitting authorities to determine pollutants of 

concern, EPA believes it is appropriate for agencies to proceed on a 

case-by-case basis using the best information available. Thus, the determination of whether the pollutants would be emitted in amounts sufficient to be 

of concern is one that the permitting authority has considerable discretion in 

making. Reasonable efforts should be made to address these issues. The EPA 

expects these efforts to include consultation with the Regional Office and with 

the Control Technology Center (CTC), National Air Toxics Information Clearinghouse, and Air Risk Information Support Center in the Office of Air Quality 

Planning and Standards (OAQPS) and review of the literature, such as 

EPA-prepared compilations of emission factors. Source-specific information 

supplied by the permit applicant is often the best source of information, and 

it is important that the company be made aware of its responsibility to provide 

for a reasonable accounting of air toxics emissions. 

Similarly, once the pollutants of concern are identified, the permitting 

authority has flexibility in determining the methods by which it factors air 

toxics considerations into the BACT determination, subject to the obligation 

to make reasonable efforts to consider air toxics. Consultation by the 

review authority with EPA's implementation centers, particularly the CTC, is 

again advised. One exception to this approach is where a municipal waste 

combustor is involved. Here, the OAQPS has provided rather detailed guidance 

regarding pollutants of concern and their control. (See memorandum of June 

22, 1987, from Gerald Emison to EPA Regional Air Division Directors.) Similar 

guidance on other source categories will be developed as appropriate. 

It is important to note that several acceptable methods, including risk 

assessment, exist to incorporate air toxics concerns into the BACT decision. 

Whatever the methods selected, these serve only to affect the selection of 

the control strategy. The overall approvability of a project once it applies 

BACT depends on other criteria, as well, and is outside the scope of the 

North County remand and this guidance. 

Level of Detail in Public Notice 

The September 22, 1987 guidance strongly emphasizes public participation. 

The purpose of the PSD public notice is to provide sufficient information as 

to the type of source involved, and its projected emissions and proposed 

controls, such that potentially interested citizens will be apprised of the 

main issues. Individuals wishing to investigate those issues in depth can 

turn to the technical support document. Our intent regarding air toxics is 

to provide the public with adequate notice of potential issues. The identification of specific toxic substances and the degree of detail in the notice 

should be consistent with the concern posed by air toxics. 

For example, if there are no air toxics projected to be emitted in 

amounts sufficient to be of concern to the permitting authority, the notice 
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can be handled very simply. One way, but by no means the only way, of doing 

this would be to note that "the [permitting authority] also considered the 

impact of available control alternatives on emissions of other pollutants, 

including those not regulated by the Clean Air Act, in making the BACT 

determination, but found that no such pollutants would be emitted in amounts 

sufficient to cause concern." 

When any toxic pollutants of concern have been identified, it is 

appropriate that the public be informed of 'them more directly. A variety of 

approaches is acceptable. Public notice requirements would be met if all these 

pollutants are mentioned individually, by name, or addressed by referring to 

them by groups (e.g., "toxic metals"). It might be reasonable to note the main 

representative pollutants (e.g., "the State has examined other pollutants of 

potential concern, including compounds A, B and C") . In short, the permitting 

authority can provide adequate notice in several ways, including the names of 

the pollutants at issue and an indication that the compounds are toxic. The 

notice can be quite brief on this subject (1-2 sentences), deferring any 

detailed analyses and discussion to the technical support document. 

EPA Oversight 

The EPA Regional Offices are now supporting State and local implementation 

of PSD review in virtually all cases and are charged with taking enforcement 

action, as necessary, to ensure proper implementation of the September 22, 

1987 policy. Action is contemplated only where basic procedural steps are 

missed, such as appropriate public notice, or inclusion of discussion of 

relevant control alternatives in the technical support document, or where the 

substantive technical analysis is clearly inconsistent with general practice. 

Priority should be given to those cases in which there is a practical impact 

to any followup—for example, more effective and affordable controls were not 

considered. 

The OAQPS is taking steps to facilitate continuing effective implementation 

of this policy. One step toward this goal is the recent addition of this policy 

in reviews of PSD permits under the National Air Audit System. 

Thank you for your progress in carrying out this significant regulatory 

requirement. If you need further assistance, please contact Michael Trutna at 

FTS 629-5345 or Kirt Cox at FTS 629-5399. 

Addressees: 

Director, Air Management Division, Regions I, III, and IX 

Director, Air and Waste Management Division, Region II 

Director, Air, Pesticides, and Toxics Management Division, Region IV 

Director, Air and Radiation Division, Region V 

Director, Air, Pesticides, and Toxics Division, Region VI 

Director, Air and Toxics Division, Regions VII, VIII, and X 

cc: Air Branch Chiefs 

New Source Review Contacts 

Air Toxics Coordinators 

OAQPS Divison Directors 

G. Emison 

J. O'Connor 

E. Lillis 

G. McCutchen 

M. Trutna 

K. Cox