A chemical used to make Teflon, Stainmaster carpets, and a host of industrial products causes developmental problems in rats at blood levels comparable to those in the general population, according to a preliminary risk assessment from the Environmental Protection Agency (EPA). As a result, EPA is accelerating its investigation of the chemical, called perfluorooctanoic acid (PFOA), and has asked companies to reduce their PFOA emissions.
PFOA is essential to a wide range of technologies for making chemicals, aircraft parts, and some electronics. Like many other perfluorinate compounds, PFOA appears to persist indefinitely in the environment. Although human studies have found small concentrations in the blood, it's not clear where the compounds are coming from. The Environmental Working Group, a nonprofit advocacy group based in Washington, D.C., has called for the compounds to be banned from industry.
EPA's risk assessment, released on 14 April, relies on troubling data from a study using two generations of rats. Rat pups whose mothers received PFOA while pregnant lost weight, matured slowly, and died more often than controls. Concentrations of PFOA in human blood are about 1% of that in the female rats--a slim margin of safety that has raised concerns. However, female rats excrete PFOA much more quickly than males--a difference not found in humans. So researchers aren't certain what the results of this study mean for people, says toxicologist Kurunthachalam Kannan of the State University of New York, Albany.
Because of "considerable scientific uncertainties" about the animal data, as well as PFOA exposure in the general population, EPA is not moving to halt PFOA production at this time, according to Stephen Johnson, who heads the EPA office that regulates chemicals.
Info and background on PFOA from EPA