Accumulating Teflon Chemical Raises Environmental Concern

Shankar Vedantam / Washington Post 19jul01

Teflon and similar chemicals may be contributing to the buildup of a pollutant in the environment that could threaten certain plant life, scientists reported yesterday.

While the pollutant -- trifluoroacetate (TFA) -- is not considered a threat to human health, scientists are concerned because the same qualities that make materials like Teflon so useful could also increase potential environmental problems.

"If you create a material that lasts a lot longer because that's what you want it to do, when it breaks up in the environment you are going to end up with smaller things that are going to last equally long," said David Ellis, a University of Toronto chemist who studied the connection between Teflon and similar substances and TFA.

DuPont Co. of Wilmington, Del., which makes Teflon, questioned the study's assumptions and conclusions. Spokeswoman Diane Shomper said that Teflon was not normally heated to the levels that the researchers used, making the conclusions questionable. "In terms of these products being safe for consumers, they are absolutely safe," she added.

Scientists have long been baffled by the levels of TFA in the environment. Researchers initially thought the TFA was coming from chemicals used in air conditioning systems. But that failed to explain the amount of TFA found.

So Ellis and his colleagues decided to examine a class of chemicals called fluoropolymers, which are used in a variety of products, including Teflon-coated frying pans, automobile additives, surgical tubing and Gore-Tex jackets. Fluoropolymers can withstand high temperatures and do not easily break down.

But chemical tests and mathematical modeling indicate that fluoropolymers can break down into chemicals that include TFA, the researchers reported in today's issue of the journal Nature.

Researchers stressed that there is no evidence that TFA is dangerous to people. But because TFA lasts so long, it could build up to levels in the environment that may pose a problem for plants, said Thomas Cahill, an environmental chemist at Trent University in Peterborough, Canada.

Another author of the paper, Derek Muir, a Canadian government scientist at the National Water Research Institute in Burlington, Ontario, said that fluoropolymers can also break down into other chemicals, including some capable of building up in people and others known to affect the earth's protective ozone layer.

"We did find minor amounts of these other chemicals which have a potential impact on the global environment," Muir said. "That's a concern, no question about it. They are not 'toxic' but they certainly have global implications in terms of their continued emission."

Shomper disputed that conclusion. "None of the fluoropolymers that DuPont makes degrade into ozone polluting substances," she said.