criticism (Williams 2003) and litigation (Sierra Club v. U.S. Environmental Protection Agency, No. 02-1135 [DC Circuit]). As of February 2003, EPA had promulgated 79 MACT standards, affecting 123 source categories (T. Clemons, EPA, Washington, DC, personal commun., March 31, 2003). In May 2003, EPA indicated that it fully expects to finalize all MACT standards by the time states would be required to set MACT limits on a facility-by-facility basis according to Section 112(j), as amended (EPA 2003b). This section, referred to as the “MACT hammer,” requires states to set MACT standards by facility-specific permit limits if EPA fails to set standards within 18 months of the statutory deadline.

Implementation of MACT standards developed so far is estimated to have already reduced HAP emissions by about 25% (EPA 2001a). Presumably, even larger reductions will be achieved when the program is fully implemented. The use of standards that directly (through a design standard) or indirectly (through a traditional performance standard) mandate the installation of specific pollution control technologies appears to have resulted in substantial reductions in pollutant emission rates (see Chapter 6). However, these technology-specific approaches have some deficiencies (see Box 5-2). They are not set up to minimize costs across all companies who must comply, nor do they provide an incentive for creative problem solving within companies that can result in the development of new, more efficient approaches to reducing emissions.


Although the technology-specific control programs have considered a range of pollutants from the start, consideration has been segmented by the programs, such as NSPS, MACT, RACT, NSR, and PSD, at federal and state levels operating on different time frames and under different levels of stringency. The result has been to make it difficult for any one facility to implement multipollutant controls in a systematic and cost-effective fashion.

Perhaps most important, older plants have not had to make emission reductions in many cases, and the emissions from these older facilities provide a substantial contribution to the emission inventories of some pollutants (see Box 5-3). This situation has been caused by (1) a complex system of requirements for new, modified, and existing facilities that has provided incentives for not retiring or modifying facilities; (2) RACT and other rules that have either been less stringent than originally intended or not been energetically enforced by some states; and (3) the relatively high cost of retrofitting, thereby providing an incentive for operators facing cap and trade to purchase reduction allowances from others who can make the reductions less expensively (see cap-and-trade discussion below).

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