The National Emission Standards for Hazardous Air Pollutants (NESHAP) are air pollution standards issued by the United States Environmental Protection Agency (EPA).
The standards, authorized by the Clean Air Act, are for pollutants not covered by the National Ambient Air Quality Standards (NAAQS) that may cause an increase in fatalities or in serious, irreversible, or incapacitating illness.
[1] The standards for a particular source category require the maximum degree of emission reduction that the EPA determines to be achievable, which is known as the Maximum Achievable Control Technology (MACT) standards.
[3] EPA regulates the following hazardous air pollutants with the MACT standards.
[5] Subsequently the agency issued several revisions and updates to the list and the regulatory promulgation schedule.