UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

RESEARCH TRIANGLE PARK. NC 27711

OFFICE OF

AIR QUALITY PLANNING

AND STANDARDS

NOV 27 1995

Mr. Timothy J. Mohin

Government Affairs Manager

Environment, Health and Safety

Intel Government Affairs

888 17th Street Northwest, #860

Washington, DC 20006-3939

Dear Mr. Mohin:

Thank you for the additional information you provided

regarding the exhaust conditioners used in tool operations in the

semiconductor industry. We agree with your assessment that, for

potential to emit calculations, the exhaust conditioners should

be considered as an inherent part of the process.

Criteria for Determining Whether Equipment is Air Pollution

Control Equipment or Process Equipment

For purposes of determining a source's potential to emit, it

is necessary to calculate the effect of air pollution control

equipment. Current Environmental Protection Agency (EPA)

regulations and policy allow air pollution control equipment to

be taken into account if federally enforceable requirements are

in place requiring the use of such air pollution control

equipment. There are, however, situations for which case-by-case

judgements are needed regarding whether a given device or

strategy should be considered as air pollution control equipment,

or as an inherent part of the process. The EPA believes that the

following list of questions should be considered in making such

case-by-case judgements as to whether certain devices or

practices should be treated as pollution controls or an inherent

to the process:.

1. Is the primary purpose of the equipment to control air

pollution?

2. Where the equipment is recovering product, how do the

cost savings from the product recovery compare to the

cost of the equipment?

3. Would the equipment be installed if no air quality

regulations are in place?
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If the answers to these questions suggest that equipment

should be considered as an inherent part of the process, then the

effect of the equipment or practices can be taken into account in

calculating potential emissions regardless of whether enforceable

limitations are in effect.

Analysis of the criteria for the semiconductor tools listed

No information supplied to date by Intel suggests that

product recovery by the exhaust conditioners is significant. That

EPA believes that the first and third criteria are satisfied.

Criteria 1. The exhaust conditioners described in your letter are

small treatment systems that are local to the point-of-use of

process tools such as etching and deposition processes. The

primary purposes are to: (1) increase the uptime of the process

tools, (2) to minimize safety hazards, and (3) to prevent

impurities from entering other processes.

Criteria 3. The information you have provided suggests strongly

that air quality regulations are not the driving factor for

installation of the equipment. Moreover, the fact that they are

"interlocked” with the process chambers suggests that the process

cannot operate unless the exhaust conditioner is in use.

Therefore, based upon a review of the information presented

the exhaust conditioners are considered by the EPA to be inherent

to the process and can be considered in potential emission

calculations without federally enforceable requirements.

Cautions

The above determination regarding the use of the localized

exhaust conditioners in the semiconductor industry is casespecific. This determination is not intended to set a precedent

for localized pollution control equipment for other source types

without a similar case-specific review.

While many types of point-of-use and interlocked treatment

device may be considered as "inherent,” there does exist, of

course, air pollution control equipment at semiconductor

facilities that may not meet the above criteria. For example, a

remote water scrubber located at the roof of a building would

generally be considered an air pollution control device.
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If you have any further questions regarding this matter,

please call Timothy Smith at (919) 541-4718, or Tony Wayne at

(919) 541-5439. 

sincerely,

David Solomon

Acting Group Leader

Integrated Implementation Group

cc: Chief, Air Branch, Regions I-X

Regional PTE Contacts