,~~~,~~~ Signs of acute toxicity appear in diets containing selenium in excess of 5 ~pm.’~~ A common form of acute selenosis in cattle, sheep, and pigs at present is accidental overs~pplementation.~~.~~J~~J~~J~~ Concern about spontaneous forms of selenosis reemerged in the early 1980s due to a controversy about the extent and significance of losses in waterfowl at the Kesterson Wildlife Refuge in California, following contamination of irrigation wastewater by selenium.L07J21J22 Wildlife biologists concluded that deaths and teratogenic effects in wildfowl were due to selenosis, and regulatory agencies subsequently tightened regulations intended to restrict the exposure of people, domestic animals, and wildlife to se1enium.l The Federal Drug Administration recently attempted unsuccessfully to reduce the approved level of selenium in animal feeds from 0.3 to 0.1 mg/kg (dry Amended regulations have potentially significant implications for producers in selenium-deficient areas, and for imgation district^^^,^^ and mining industrie~~~,~~,~~ in seleniferous areas. Reviewers of the extent of selenosis in people living in seleniferous areas in the United States conclude that the problem is ~are.~O.~’ A localized problem developed under unusual circumstances in people in one area of China.163 Notwith