The EPA has proposed amendments to the general provisions of the National Emission Standards for Hazardous Air Pollutants (NESHAP) this past January. The proposal would replace the 1995 memorandum entitled Potential to Emit for MACT Standards.

The proposed amendments provide that a major source may become an area source at any time by limiting its potential to emit hazardous air pollutants (HAPs) to below the major source thresholds of 10 tons per year (tpy) of any single HAP or 25 tpy of any combination of HAPs. Under the proposed amendments, a major source can become an area source at any time, including after the first substantive compliance date of an applicable maximum achievable control technology (MACT) standard so long as it limits its potential to emit to below the major source thresholds. The agency also proposed to revise tables of numerous MACT standards that specify the applicability of the general provisions requirements to account for the regulatory provisions it is proposing to add. The agency has set a deadline for comments at March 5, 2007.

See the Federal Register, Jan. 3, 2007 vol. 72, No. 1, pages 69-92.