Agent Name
Alternative Name
Selenium and compounds
CAS Number
7782-49-2; varies
Se, varies
Major Category
Other Classes
Elemental selenium; Selenium alloy; [NIOSH] Selenium compounds; Selenium and compounds; UN2658
Other Inorganic Compounds
Amorphous or crystalline, red to gray solid; Note: Occurs as an impurity in most sulfide ores; [NIOSH]
Selenium is an essential trace element in the body. It is present in high concentrations in some soils. In industry, selenium exposure can occur in copper smelting and in the production of pigments, glass, rubber, plastics, pharmaceuticals, and electronic devices. [ACGIH] Used to make photocells, solar cells, photographic exposure meters, and rectifiers; also used as a vulcanizing agent, a glass decolorizer, a photographic toner, and a stainless steel additive; [Rom, p. 1092] Fly ash from burning coal is the major emission source; [ATSDR ToxProfiles]
"Selenosis" has been documented in animals and humans living in areas with high selenium contamination of soil and groundwater. In humans, symptoms of this disease include fatigue, dermatitis, gastrointestinal disturbances, garlic odor of the breath and sweat, and increased dental caries. Liver injury is observed in feeding studies of experimental animals. [ACGIH] Burning selenium produces selenium dioxide fume, an irritant inhalant that can induce pulmonary edema at sufficient dose; [Harber, p. 502] In high-dose reproductive studies in animals, selenium causes low birth weight and birth defects. [ATSDR Case Studies #29] Chinese villagers studied in 1983 developed selenosis after using coal ash as a crop fertilizer. They also inhaled smoke from burning coal indoors. In extreme cases with intake averaging 0.09 mg/kg/day, patients developed neurological disease including increased tendon reflexes, convulsions, and paralysis. Similar neurological problems have been observed in animals fed high doses of selenium. A NOAEL of 0.015 mg selenium/kg/day corresponding to a blood level of 0.97 mg/L was calculated. The calculated LOAEL was 0.023 mg selenium/kg/day. The recommended dietary allowance (RDA) for selenium is 0.001 mg/kg/day. Follow-up in 1992 revealed that villagers with hair loss and nail deformities recovered and that average blood levels dropped from 1.346 mg/L to 0.819 mg/L. [ATSDR ToxProfiles] The most common compound reported in cases of selenium poisoning by ingestion is 4% selenious acid in gun bluing (coating) solutions. As little as 15 ml can be fatal. Patients have corrosive gastroenteritis with vomiting, diarrhea, and garlic odor. Other compounds reported in poisoning cases by ingestion are selenium dioxide, sodium selenate, and sodium selenite. [Olson, p. 416-418] See "Hydrogen selenide."
Reference Link #1
Biomedical References

Exposure Assessment

Skin Designation (ACGIH)
Insufficient data
0.2 mg/m3, as Se (metal and compds)
0.2 mg/m3, as Se (compds.)
0.02 mg/m3, as Se, inhalable fraction (metal and inorganic compds)
1 mg/m3, as Se
Excerpts from Documentation for IDLHs
The revised IDLH for selenium compounds is 1 mg Se/m3 based on acute toxicity data in animals [Olson 1986; Pletnikova 1970a, 1970b]. This may be a conservative value for selenium compounds in general since it is based on sodium selenite, which is orders of magnitude more toxic than many other selenium compounds. Further, this may also be a conservative value due to the lack of relevant acute toxicity data for workers.
Lethal Concentration
LCLo (rat) = 33 mg/m3/8 hr
Explanatory Notes
Melting point = 392 degrees F; Boiling point = 1265 degrees F; VP = 0 (approx); [NIOSH] The Guide from the Emergency Response Guidebook is for "Selenium powder."
Half Life
Whole body: 140 days; [TDR, p. 1075]
Reference Link #2

Adverse Effects

Toxic Pneumonitis
Other CNS neurotoxin
Hepatoxic (a) from occupational exposure (secondary effect) or (b) in animal studies or in humans after ingestion
Reproductive Toxin
IARC Carcinogen
Not classifiable

Diseases, Processes, and Activities Linked to This Agent