National Emission Standards for Hazardous Air Pollutants: Generic Maximum Achievable Control Technology

This action proposes amendments to the "generic" maximum achievable control technology (MACT) standards to add national emission standards for hazardous air pollutants (NESHAP) for four additional source categories: Cyanide Chemicals Manufacturing, Carbon Black Production, Ethylene Production, and Spandex Production. The generic MACT standards provide a structural framework allowing source categories with similar emission types and MACT control requirements to be covered under one subpart, thus promoting regulatory consistency in NESHAP development. The EPA has identified these four source categories as major sources of hazardous air pollutants (HAP), including cyanide compounds, acrylonitrile, acetonitrile, carbonyl sulfide, carbon disulfide, benzene, 1,3 butadiene, toluene, and 2,4 toluene diisocyanate (TDI). Benzene is a known human carcinogen, and 1,3 butadiene is considered to be a probable human carcinogen. The other pollutants can cause noncancer health effects in humans. These proposed standards will implement section 112(d) of the Clean Air Act (CAA) by requiring all major sources to meet HAP emission standards reflecting the application of MACT.