If you found out that cyanide was found in common mass market products, you would probably avoid them. But sodium selenite, a chemical that is actually 4 times more toxic than cyanide, is actually listed as a "nutrient" on the labels of many such products. A human has a 50 percent chance of dying after consuming only 108 milligrams of sodium selenite -- that's just 108 millionths of a gram.
Products that use sodium selenite include selenium supplements, nutrition shakes, pet food, infant formula, and multi-vitamins.
According to Green Med Info:
“The selenium that is found in foods like brazil nuts, mustard seeds, and fresh produce grown in selenium-rich soil is infinitely different from the biologically inert forms being put in some multivitamins ... The primary reason that sodium selenite/selenate are preferred by some vitamin manufacturers over safer, more beneficial forms ... is because it is more profitable to use raw materials of lower quality.”