While<unk>  is stable and nontoxic at lower temperatures, it begins to deteriorate at temperatures of about , it decomposes above , and pyrolysis occurs at temperatures above . The main decomposition products are fluorocarbon gases and a sublimate, including tetrafluoroethylene (TFE) and difluorocarbene radicals (RCF2). An animal study conducted in 1955 concluded that it is unlikely that these products would be generated in amounts significant to health at temperatures below . Above those temperatures the degradation by-products can be lethal to birds, and can cause flu-like symptoms in humans (polymer fume fever), although in humans those symptoms disappears within a day or two of being moved to fresh air. Most cases of polymer fume fever in humans occurr due to smoking<unk> -contaminated tobacco, although cases have occurred in people who have welded near<unk>  components or heated<unk> -coated cookware at for at least 4 hours. Teflon-coated cookware is unlikely to reach dangerous temperatures with normal use, as meat is usually fried between , and most cooking oils (except refined safflower and avocado oils) start to smoke before a temperature of is reached. A 1973 study by DuPont's Haskell Laboratory found that a 4-hour exposure to the fumes emitted by teflon cookware heated to was lethal for parakeets, although that was a higher temperature than the required for fumes from pyrolyzed butter to be lethal to the birds. Perfluorooctanoic acid (PFOA), a chemical formerly used in the manufacture of<unk>  products such as non-stick coated cookware, can be carcinogenic for people who are exposed to it (see Ecotoxicity). Concerning levels of PFOA have been found in the blood of people work in or live near factories where the chemical is used, and in people regularly exposed to PFOA-containing products such as some ski waxes and stain-resistant fabric coatings, but non-stick cookware was not found to be major sources of exposure as the PFOA is burned off during the manufacturing process and not present in the finished product. Non-stick coated cookware has not been manufactured using PFOA since 2013, and PFOA is no longer being made in the United States.
Polytetrafluoroethylene
Spirolactone
Polymethylsiloxane polyhydrate
Alpha-Zearalenol
Cromoglicic acid
Beta-Zearalenol
Methyl cellulose
Asthmagen