Hazardous Air Pollutants
Hazardous air pollutants are those known to cause cancer and other serious health impacts. The Clean Air Act requires the EPA to regulate toxic air pollutants, also known as air toxics, from categories of industrial facilities in two phases. The first phase is “technology‑based,” where the EPA develops standards for controlling the emissions of air toxics from sources in an industry group (or “source category”). These technology standards are based on emissions levels that are already being achieved by the best‑controlled and lower‑emitting sources in an industry. Within eight years of setting the technology standards, the Clean Air Act directs the EPA to assess the remaining health risks from each source category to determine whether the standards protect public health with an ample margin of safety, and protect against adverse environmental effects.