May 18, 1998

Mr. Brian L. Taranto

Safety and Environmental Affairs

Exxon Chemical Americas

Post Office Box 3272

Houston, Texas 77253-3272

Dear Mr. Taranto:

This is in response to your April 13, 1998 letter that asks this office to clarify one statement in a November 12, 1997 memorandum entitled "Crediting of Maximum Achievable Control Technology (MACT) Emission Reductions for New Source Review (NSR) Netting and Offsets."

You specifically request whether under the section dealing with "Offset Policy" the phrase " . . . reductions required to meet the MACT standards at 40 CFR part 60 and part 61 . . . " correctly references the MACT standards that are adopted to implement section 112 of the Clean Air Act. In reviewing this, we realize that the phrase you referenced does not correctly reference the MACT standards in part 63 and also does not clarify that part 61 contains the National Emissions Standards for Hazardous Air Pollutants (NESHAP). To be correct the phrase should read " . . . reductions required to meet the NESHAP standards at 40 CFR part 61 and the MACT standards at 40 CFR part 63 . . . ."

Thank you for pointing out this incorrect reference in the memorandum. A copy of this letter will be added to the technology transfer network (TTN) NSR bulletin board. The bulletin board may be accessed through the TTNWeb site at hppt://www.epa.gov/ttn under NSR-New Source Review information. If you have any further questions about this response, you may contact Mike Sewell of the Integrated Implementation Group at (919) 541-0873.

I appreciate this opportunity to be of service and trust that this information will be helpful to you.

Sincerely,

s/ Henry Tomas for

John S. Seitz

Director

Office of Air Quality Planning

and Standards

EPA/OAQPS/ITPID/IIG:MSEWELL:cbaines:x1-5319:MD-12:05/04/98:

Filename: a: Sewell/taranto. Revised: 5/11, 5/9 & 5/8/98

File: 141 (Exxon Control on MACT Offsets Policy)

Control No: AQPS-98-0424	Due Date: 5/6/98

bcc:	Regional Air Division Dirctors, I-X

NSR Contacts