July 18, 2001 -- Our cooking pans may be nonstick, but they're sticking something to our environment, according to a new report. Canadian researchers have found that a chemical found in almost every kitchen cabinet breaks down into components that will stay in the environment indefinitely with undetermined but possibly harmful effects.
The well-known chemical Teflon, or polytetrafluoroethylene (PTFE), coats many nonstick frying pans, cooking utensils, oven interiors, and other products. When heated, the chemical degrades into other compounds, one of which is known to be mildly toxic to plants and another known to accumulate in human and animal tissues, according to a report in the July 19 issue of Nature.
Author David Ellis, PhD, explains that while little is known about what kind of health effects the compounds have on humans, the compounds are extremely "environmentally persistent" -- meaning they will stay in the environment and accumulate over a long period.
A very long period, Ellis says.
"To [get rid of] them will take a thousand years to tens of thousands of years," he tells WebMD. "These chemicals may not be released in significant amounts presently, but if we continue to release them, they will accumulate simply because there is no natural way to degrade them." Ellis is a research associate in the department of chemistry at University of Toronto.
The compounds produced by heating Teflon include trifluoroacetate and perflurocarboxylate. One 1998 study appearing in the International Journal of Cancerfound that compounds similar to perflurocarboxylate might promote tumor growth.
However, DuPont Corporation, the maker of Teflon, maintains that the nonstick product is safe. Before Teflon was made available to consumers, DuPont put the product under exhaustive tests. "Tests have repeatedly shown that DuPont non-stick coatings are safe for normal kitchen use," the manufacturer said in a prepared statement.
Ellis says thisstudy was undertaken following studies showing high levels of trifluoroacetate in the environment that could not be accounted for.
Based on its own studies, DuPont argues that the nonstick coatings only begin to degrade at temperatures "well above normal cooking temperatures" -- when temperatures reach 500°F. Significant decomposition of the coating occurs when temperatures rise above 600°F. Fats, butter, and cooking oil begin to scorch and smoke at about 390°F, according to DuPont.
"We asked ourselves what could be producing these levels," Ellis says. "We thought it had to be something that is predominantly urban and that people would be using in large enough quantities to see it in the environment."
Scott Mabury, PhD, another study author, says the findings beg for more research to determine the toxicity of these compounds. "Because they are so persistent, we should be looking at whether they are toxic," he tells WebMD. Mabury is associate professor of environmental chemistry at the University of Toronto.
Ellis says the finding underscores the downside that comes with human ingenuity.
Tee Guidotti, MD, MPH, director of the division of occupational medicine and toxicology at George Washington University Medical Center in Washington, agrees. "This is a classic example of how we are constantly playing catch-up," he tells WebMD. "We introduce these chemicals into the environment without a clear idea of their toxicity."
"These compounds are biologically active and many have unanticipated side effects," Guidotti says. "Some of these compounds do have a destabilizing effect on natural ecosystems, which is also not good for human health. Whether this is going to be a problem remains to be seen."
DuPont is not aware of any reports of serious, chronic, or acute health problems related to using nonstick cookware. The FDA and health regulatory agencies around the world consider nonstick cookware acceptable for conventional kitchen use, DuPont adds.