Selenium is a metal found in natural deposits as ores containing other elements.
The greatest use of selenium compounds is in electronic and photocopier components, but they are also widely used in glass, pigments, rubber, metal alloys, textiles, petroleum, medical therapeutic agents, and photographic emulsions. Production in 1985 was reported to be 429,515 pounds. Selenium compounds are released to the air during the combustion of coal and petroleum fuels, and during the smelting and refining of other metals. From 1987 to 1993, according to the Toxics Release Inventory selenium releases to land and water totaled over 1 million lbs. These releases were primarily from copper smelting industries.