Heating nonstick coatings such as the Teflon on pots and pans can generate a chemical compound that persists in the environment indefinitely, research has found.
There is no evidence that the compound, trifluoroacetate, poses any threat to human health, said study author Scott Mabury. But because of its longevity and some of the other chemicals his research saw Teflon and similar substances producing, Mabury recommended more research on the potential environmental effects.
Mabury and three colleagues reported their findings in today's issue of the journal Nature.
The scientists heated various fluoropolymers, which are used as non-stick coatings, engine oil additives and other products, to temperatures between 400 and 900 degrees. The heat caused a gradual breakdown of the fluoropolymers into a variety of compounds that were released into the air.
The researchers said the compounds are also released, though more slowly, at normal cooking temperatures. They did not look at whether the compounds get into food during cooking.
Among the compounds released were a witches' brew of environmentally suspect chemicals. Besides trifluoroacetate, they included:
Polyfluorocarboxylic and polyfluorocarboxylic acids, a family of chemicals that includes one being phased out of Scotchguard and other products because it accumulates in the human body.
Fluorocarbons, which contribute to global warming by trapping heat in the atmosphere.
Trifluoroacetate, or TFA, is known to be mildly toxic to some plants. Because it takes decades or centuries to break down, some scientists have speculated it could accumulate and cause harm in certain locations, such as wetlands.
"The consequences of this TFA have never really been looked into," said Charles Driscoll, a professor at Syracuse University.
But there is little reason to believe that TFA or any of the other substances produced by heating fluoropolymers are causing serious environmental damage, Mabury said. "There's not lots to worry about, frankly," said Mabury, a professor of chemistry at the University of Toronto.