National Emission Standards for Hazardous Air Pollutants for Primary Magnesium Refining

This action promulgates national emission standards for hazardous air pollutants (NESHAP) for primary magnesium refining facilities. The EPA has identified primary magnesium refining facilities as a major source of hazardous air pollutant (HAP) emissions. The NESHAP implement section 112(d) of the Clean Air Act (CAA) by requiring all major sources to meet HAP emission standards reflecting application of the maximum achievable control technology (MACT). The HAP emitted by facilities in the primary magnesium refining source category include chlorine, hydrochloric acid, dioxin/furan, and trace amounts of several HAP metals. Exposure to these substances has been demonstrated to cause adverse health effects, including chronic and acute disorders of the blood, heart, kidneys, reproductive system, and central nervous system. Some of these pollutants are considered to be carcinogens, and all can cause toxic effects in humans following sufficient exposure.