What has been done to reduce toxic air pollutants?
The Clean Air Act Amendments of 1970 required that the U.S. Environmental Protection Agency (EPA) develop standards to regulate emissions of toxic air pollutants, also known as hazardous air pollutants (HAPs). The standards regulate HAP emissions from new and existing sources on a pollutant-by-pollutant basis. This proved to be a difficult challenge for EPA to develop and promulgate these standards because they had to be risk-based and had to provide “an ample margin of safety.” EPA was continuously challenged on the basis that the “ample margin of safety” was either too strict or not strict enough. Due to these challenges, only seven HAP standards were promulgated in twenty years. These standards are referred to as National Emission Standards for Hazardous Air Pollutants (NESHAPs) and are found in Title 40 of the Code of Federal Regulations Part 61 (40 CFR Part 61). A different approach was taken to regulate HAP emissions in the Clean Air Act Amendments of 1990. The 1990 amendments re
