DuPont disputes PFOA cancer claim25 July 2005
Elevated cancer rates have allegedly been found in and around a DuPont plant where PFOA is used to create Teflon pans but DuPont are disputing the recent study that claims exposure to the perfluorooctanoic acid used to manufacture Teflon and other fluoropolymers at one of their chemical plants in West Virginia causes an increased risk of cancer. The study claims that plant workers and neighbours whose drinking water contains the perfluorinated compound have cancer rates several times higher than those of the general population. Like perfluorooctane sulfonate (PFOS), which was once used to make Scotchgard fabric protector, PFOA appears to be present at low levels in people living far from any obvious sources. The mystery of how these are generated has prompted investigations by scientists, industry and the US EPA. PFOA is acknowledged to cause cancer in animals, but studies of industrially exposed workers have not shown a conclusive cancer link. DuPont's Washington Works plant, located on the Ohio River, has used PFOA—also called C8—for more than 50 years. For most of that time, DuPont released PFOA into the air, local landfills, and the adjacent Ohio River. Groundwater around the plant also contains the perfluoroacid. PFOA water concentrations near the Washington Works plant range from about 1 part per billion (ppb) to 8 ppb. This concentration is substantially less than the 150 ppb level of concern established by West Virginia in 2002. The West Virginia study was conducted by James Dahlgren, a toxicologist at the University of California, Los Angeles, on behalf of plaintiffs in a class action lawsuit filed against DuPont. The 2001 suit alleges that DuPont knowingly contaminated local water systems with PFOA and that the chemical causes adverse health effects. Dahlgren presented the data at the Society of Environmental Toxicology and Chemistry meeting in Prague, Czech Republic, in April this year. Dahlgren and colleagues compared cancer incidence from three different sources for three different groups: a survey of 599 residents living near DuPont's Washington Works plant in West Virginia, unpublished health records of more than 5000 DuPont employees that were obtained as part of the lawsuit, and data for cancer prevalence in the United States as a whole. The class action lawsuit includes all nearby residents who have PFOA levels of at least 0.5 micrograms per liter in their drinking water and have lived in the area for at least a year. Dahlgren says: 'It's possible that the explanation is some factor other than PFOA exposure, but the most likely explanation is exposure to PFOA and other perfluorinated compounds.' 'Based on what we have seen, we question the scientific validity of the conclusion in the report' says Robin Leonard, principal epidemiologist for DuPont. For example, he says, the study did not control for other factors that might affect cancer rates. 'There is no indication that other factors impacting the health of populations were considered or analyzed', Leonard charges. DuPont are conducting their own $1 million survey of possible PFOA effects on 750 volunteer employees at the Washington Works plant which will compare the results of employees who work in the company's Teflon unit, the area where PFOA is primarily used, and those who work elsewhere.