Developing Regulations to Limit Emissions of Hazardous Air Pollutants under the Clean Air Act Amendments

In 1970, Congress passed Amendments to the Clean Air Act which included a provision requiring the EPA to reduce emissions of hazardous air pollutants (HAPs). The Amendments required the agency to promulgate emission standards that would provide an ample margin of safety to protect public health. The EPA was largely unsuccessful in promulgating rules under this framework. In 1990, Congress passed new Amendments to the Clean Air Act. These Amendments significantly changed the way the EPA was to develop emission standards for HAPs. The new Amendments require the agency to first set standards based on existing methods to emissions reduction, then evaluate remaining public health risks, within eight years, and set risk-based standards if necessary. The 1990 Amendments attempted to remove major impediments to standard setting under the former program: listing chemicals as HAPs was largely eliminated; setting health-based standards was postponed and may not be necessary in all cases; and deadlines were extended. The EPA has made some internal progress as a result of these changes but it still far behind its mandated regulatory schedule. How the agency succeeds as implementation proceeds will depend on how it manages the intractable regulatory process, and how it prepares for the second, risk-based phase of the program.