Title III of the federal Clean Air Act Amendments of 1990 (CAAA) substantially Changes the way hazardous air pollutants (HAPs) are to be regulated. These changes pollutants (HAPs) are to be regulated. These changes include many significant considerations for the oil and gas industry, despite some favorable language on the "aggregation" of emissions from oil and gas exploration and production (E and P) sources.
Title III of the CAAA establishes a completely new framework for HAP regulation at Section 112 of the Clean Air Act. Previously, (HAP) regulations were adopted on a pollutant-by-pollutant basis. The risks of an individual HAP were assessed and, if determined to be significant, control requirements were developed. This risk-based regulatory approach proved cumbersome, and only eight NAP regulations were developed under the old program. Apparently this was too slow in the eyes of program. Apparently this was too slow in the eyes of Congress, which sought a new framework with the CAAA that would statutorily force the regulation of a vastly increased list of air toxics. In Title III, Congress listed 189 chemicals or groups of chemicals that should be regulated as HAPs without need for further risk assessment. Table 1 lists HAPs of interest to E and P. Technology based control requirements are to be phased in for emissions of HAPs as discussed below. Thus, the CAAA took us from a risk driven approach to a technology driven approach with Congress deciding i priori the NAPs to be regulated. priori the NAPs to be regulated. A "major source" of HAPs is defined as one which emits 10 tons per year (TPY) of any one HAP or 25 TPY of any combination of HAPs. The CAAA directed the U.S. Environmental Protection Agency (EPA) to place the various types sources into categories and subcategories. This categorization was proposed in June 1991. This and the other regulatory deadlines mandated by the act are shown in Table 2. The EPA must then rank the categories and establish the "maximum achievable control technology" (MACT) for major sources in the 40 highest priority categories within two years of enactment. MACT priority categories within two years of enactment. MACT for an additional 25% of the listed categories must be developed within four years of enactment, for another 25% again after seven years, and then for all remaining categories within 10 years.
MACT for new sources is defined by statute to represent the emission control achieved in practice by the best controlled similar source. For existing sources MACT must be no less stringent than the best performing 12% of the sources in the category. EPA must consider costs, health and environmental impacts, and energy requirements when determining MACT, but can look beyond "end of pipe controls" to potentially include process changes, work practices, and other non-hardware process changes, work practices, and other non-hardware oriented types of controls. Sources that are not "major" as defined above are called "area" sources and are subject to less stringent "generally available control technology" (GACT). New sources must be built in compliance with any standard that is developed, and existing sources must retrofit to match required controls on a schedule established by EPA not to exceed three years.
Although this is a "technology first" approach, there are also provisions to assess any "residual risk" that remains after the application of MACT and GACT to each subcategory. This review will usually take place several years after MACT and GACT have been in place.