More than 50 years after DuPont started producing Teflon ... federal officials are accusing the company of hiding information suggesting that [the chemical] might cause cancer, birth defects and other ailments. Environmental regulators are particularly alarmed because scientists are finding perfluorooctanoic acid, or PFOA, in the blood of people worldwide and it takes years for the chemical to leave the body. The U.S. Environmental Protection Agency reported last week that exposure even to low levels of PFOA could be harmful. With virtually no government oversight, PFOA has been used since the early 1950s. Questions about potential effects on human health and the environment often aren't raised until years after a chemical is introduced to the marketplace. The long and mostly secret history of PFOA began to unravel down the road from DuPont's Teflon plant...where a Parkersburg family began asking questions in the late 1990s about a mysterious wasting disease killing their cattle. Their lawsuit ended with a monetary settlement ... but the legal battle uncovered a trove of industry documents about PFOA. One document detailed how DuPont scientists started warning company executives to avoid human contact with PFOA as early as 1961. Industry tests later determined the chemical accumulates in the body [and] doesn't break down in the environment. Tests on lab animals have found links to illnesses including liver and testicular cancer, reduced weight of newborns and immune-system suppression. The findings concern EPA officials because rats flush the chemical out of their bodies within days, while PFOA stays in human blood for at least four years.