U.S. Magnesium Corporation

Formerly the Magnesium Corporation of America (MagCorp), the US Magnesium Corporation of Salt Lake City (USMC-SLC) has been atop the EPA's Toxic Release Inventory for a number of years, as the largest toxic air polluter in the country.

According to 1998 data, USMC-SLC emitted 57.7 million pounds of chlorine gas into the atmosphere. The waste-water ditches around USMC-SLC are contaminated with dioxin at levels as high as 170 parts per billion. (EPA action levels for clean-up begin at one part per billion.)