DuPont, the sole North American producer of the chemical perfluorooctanoic acid (PFOA) disagrees with a draft report from an independent scientific review panel suggesting that the chemical should be considered a "likely" carcinogen.
The panel, which is advising the Environmental Protection Agency (EPA), said in a draft report on Monday: "The predominant panel view was that the descriptor 'likely to be carcinogenic' was more consistent with currently available data."
The recommendation goes beyond the EPA's own verdict that there was only "suggestive evidence" from animal studies that PFOA and its salts are potential human carcinogens.
DuPont's director of health and environmental sciences, Robert Rickard, said: "We disagree with the panel's recommendation on the cancer classification, and we continue to support the EPA's draft risk assessment.
Rickard said the carcinogenicity classification was based on animal data and did not reflect data from human studies.
"This reflects recommended classification; what's more important is risk, and we are confident that PFOA does not pose a cancer risk to the general public," he said.
PFOA is used as a processing aid in manufacturing fluoropolymers, which have a variety of product applications, including nonstick cookware.
The chemical also can be a byproduct in the manufacturing of fluorotelomers used in surface protection products for applications such as stain-resistant textiles and grease-resistant food wrapping.
"They've asked them to do a more rigorous analysis; that's just good science"
Besides disagreeing with the EPA on the potential carcinogenicity of PFOA, also known as C-8, a majority of members on the review panel also recommended that the EPA's risk assessment include additional data on PFOA's potential to cause liver, testicular, pancreatic and breast cancers.
"The real outcome of this is the panel going back and saying 'You've got to include this extra stuff here; it wasn't really a rigorous analysis,'" said Tim Kropp, a senior scientist for the Environmental Working Group, a Washington, DC-based non-profit organisation whose work has prompted increased government scrutiny of PFOA.
While the EPA is free to accept or reject the panel's recommendations, Kropp has said it is rare for the EPA to dismiss an advisory board's advice.
"They've asked them to do a more rigorous analysis, to do a more scientific method of determining risk, and you can't argue with that," he said. "That's just good science."
EPA officials declined to say how the agency might respond to the report.