The draft report released by the Washington-based Environmental Working Group, which advocates regulation of chemicals, says ammonium perfluorooctanoate accumulates in human blood and demonstrates toxic properties.
The chemical, also referred to as C8, has been used by DuPont's Washington Works plant for more than 50 years. A class-action lawsuit filed by customers of the Lubeck Public Service District in Wood County, W.Va., claims their drinking water has been contaminated by the chemical.
The chemical also has been found in water samples in Little Hocking, Ohio.
Earlier this month, DuPont defended C8, saying although it causes cancer to animals in laboratory tests, no adverse human health effects have been found.
"We still stand by that," plant spokesman George Ainsley said Friday.
The EPA draft report is based on a study of rats and reviews of health screenings conducted at three separate 3M plants. It does not mention DuPont's Wood County plant.
The report estimated that women of childbearing age and girls ages 2 to 12 have a margin of exposure from 66 to 80. EPA considers numbers below 100 to indicate unacceptable risk. Men and boys were estimated to have a margin of exposure from 9,125 to 11,108.
The EPA said the agency was not ready to make a judgment about the chemicals.
"We are concerned enough about it to take it to the next step, because we don't know enough about the situation," said spokesman Joe Martyak.