FOCUS ON PERFLUOROS
EPA boosts scrutiny of chemicals due to concerns of possible health effects
EPA last week intensified its investigation of chemicals used to manufacture fluoropolymers such as DuPont's Teflon, citing concerns about toxicity and the public's exposure to perfluorooctanoic acid and its salts. These compounds are lumped together under the acronym PFOA.
|Stephen L. Johnson, EPA assistant administrator for prevention, pesticides, and toxic substances nson
"To ensure consumers are protected from any potential risks, the agency will be conducting its most extensive scientific assessment ever undertaken" on perfluorinated substances, says Stephen L. Johnson, EPA assistant administrator for prevention, pesticides, and toxic substances.
Laboratory studies show that PFOA causes developmental toxicity in rats, and a preliminary assessment by EPA indicates that the U.S. public is exposed to the chemical at very low levels. However, Johnson says, the agency does not have enough scientific information to determine whether the substance presents an "unreasonable risk" to human health. EPA did not recommend that consumers stop buying or using goods made with PFOA, such as nonstick cookware and stain-resistant fabrics.
The most commonly used PFOA is ammonium perfluorooctanoate, often abbreviated C8. It is a surfactant that aids in polymerization of fluoropolymer resins but is substantially removed in the final steps of the manufacturing process.
EPA isn't sure how PFOA detected in human blood samples enters people's bodies. According to the agency, "The limited geographic locations of fluorochemical plants making or using the chemical suggest that there may be additional sources of PFOA in the environment."
DuPont is the only domestic producer of PFOA, manufacturing C8 in Fayetteville, N.C. Asahi Glass Fluoropolymers USA, Daikin America Inc., Dyneon, and DuPont use C8 at U.S. manufacturing sites. 3M produced PFOA from 1969 to 2002, when it stopped manufacturing this and related compounds and reformulated its Scotchguard products that were based on perfluorooctanyl sulfonate.
EPA is eyeing fluorinated telomers--short polymers--as possible sources of PFOA in the environment. Telomers aren't manufactured using PFOA, but some studies indicate that they can biodegrade into PFOA, Johnson says. Products made with telomers include fire-fighting foams; personal care and cleaning products; and stain-repellent coatings on carpets, paper, and fabrics. Manufacturers and U.S. importers of telomers are AGA Chemicals, Clariant GmbH, Daikin America, and DuPont.
In June, EPA will begin public negotiations with makers and importers of PFOA and fluorinated telomers on further toxicity and environmental fate tests, Johnson says. The agency hopes to strike a consent agreement under which industry will voluntarily sponsor the specific studies EPA needs for its intensified assessment.
As the agency steps up its investigation of PFOA, it is asking companies for data on uses and production and importation volumes for the compounds. Meanwhile, fluoropolymer manufacturers have pledged to reduce their emissions of PFOA and determine if their finished products release the substance. Telomer producers are evaluating their products sold in the U.S. to determine whether they are a significant source of PFOA exposure.
Meanwhile, Johnson says EPA will investigate an allegation by the Environmental Working Group (EWG) that DuPont illegally withheld a study on C8 done two decades ago. It involved female employees at a C8 plant and their babies. EWG claims that, under federal law, DuPont should have sent the report to EPA in the early 1980s. DuPont refutes the allegation.
A DuPont statement says, "There is no evidence indicating adverse human health effects related to low levels of exposure to PFOA." Richard J. Anguillo, vice president and general manager for DuPont Fluoroproducts, says the company supports "a well-informed regulation" of PFOA to help assure people they are not being exposed to undue health risks.--
"Considerable scientific uncertainties remain. We are not at the end of the process, rather at then beginning."
Chemical & Engineering News
Copyright © 2003 American Chemical Society