Antimony

Antimony: A silvery-white earth metal which at high levels can be toxic. Antimony occurs naturally in the earth. Antimony ores are mined and then mixed with other metals to form antimony alloys or combined with oxygen to form antimony oxide. Antimony breaks easily, but when mixed into alloys, it is used in lead storage batteries, solder, sheet and pipe metal, bearings, castings, and pewter. Antimony oxide is added to textiles and plastics to prevent them from catching fire and is also used in paints (especially enamels), ceramics, and fireworks.

Antimony is released into the environment from natural sources and industry. In the air, antimony attaches to very small particles that may stay there for many days. Most antimony ends up in soil, where it attaches strongly to particles that contain iron, manganese, or aluminum. Antimony is found at low levels in some rivers, lakes, and streams.

Because antimony is found naturally in the environment, the general population is exposed to low levels of it every day, primarily in food, drinking water, and air. It may be found in air near industries that process or release it, such as smelters, coal-fired plants, and refuse incinerators. Workers in industries that process it or use antimony ore may be exposed to higher levels.

Exposure to antimony at high levels can result in a variety of adverse health effects. Breathing high levels for a long time can irritate the eyes and lungs and can cause heart and lung problems, stomach pain and ulcers, diarrhea, and vomiting. Ingesting large doses of antimony can also cause vomiting. Antimony can irritate the skin if it is left on it. Antimony is known to trigger lichen planus — a recurring itchy inflammatory rash on the skin or in the mouth.

Antimony can have beneficial effects. Antimony-containing compounds (meglumine antimonate and sodium stibogluconate) are the principal medications used to treat leishmaniasis (kala-azar), an infection caused by a protozoan parasite.

The Environmental Protection Agency (EPA) allows 0.006 parts of antimony per million parts (0.006 ppm) of drinking water. The Occupational Safety and Health Administration (OSHA) has set an occupational exposure limit of 0.5 milligrams of antimony per cubic meter of air (0.5 mg/m3) for an 8-hour workday, 40-hour workweek. The American Conference of Governmental Industrial Hygienists (ACGIH) and the National Institute for Occupational Safety and Health (NIOSH) currently recommend the same guidelines for the workplace as OSHA.