Editing Polytetrafluoroethylene (section)

== Safety ==
While PTFE is stable at lower temperatures, it begins to deteriorate at temperatures of about {{convert|260|C}}, it decomposes above {{convert|350|C}}, and [[pyrolysis]] occurs at temperatures above {{Convert|400|C|F|abbr=on}}.<ref name=":3">{{cite journal |last1=Sajid |first1=Muhammad |last2=Ilyas |first2=Muhammad |title=PTFE-coated non-stick cookware and toxicity concerns: a perspective |journal=Environmental Science and Pollution Research |date=October 2017 |volume=24 |issue=30 |pages=23436–23440 |doi=10.1007/s11356-017-0095-y |pmid=28913736 |bibcode=2017ESPR...2423436S }}</ref> The main decomposition products are [[fluorocarbon]] gases and a [[Sublimation (phase transition)|sublimate]], including [[tetrafluoroethylene]] (TFE) and [[difluorocarbene]] [[Radical (chemistry)|radicals]] (RCF2).<ref name=":3" />

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 {{convert|250|C}}.<ref name="zapp">{{cite journal |vauthors=Zapp JA, Limperos G, Brinker KC |title= Toxicity of pyrolysis products of 'Teflon' tetrafluoroethylene resin |journal= Proceedings of the American Industrial Hygiene Association Annual Meeting |date=26 April 1955}}</ref> Above those temperatures the degradation by-products can be lethal to [[bird]]s,<ref>{{cite news|publisher=DuPont|title=Key Safety Questions About Teflon Nonstick Coatings|url=http://www2.dupont.com/Teflon/en_US/products/safety/key_questions.html#q6|access-date=28 November 2014|archive-date=2 May 2013|archive-url=https://web.archive.org/web/20130502210638/http://www2.dupont.com/Teflon/en_US/products/safety/key_questions.html#q6|url-status=dead}}</ref> and can cause [[flu-like symptoms]] in humans ([[polymer fume fever]]),<ref>{{cite web|publisher=DuPont|url=http://www2.dupont.com/Teflon/en_US/products/safety/key_questions.html#q5|title=Key Safety Questions about the Safety of Nonstick Cookware|access-date=28 November 2014|archive-date=2 May 2013|archive-url=https://web.archive.org/web/20130502210638/http://www2.dupont.com/Teflon/en_US/products/safety/key_questions.html#q5|url-status=dead}}</ref> although in humans those symptoms disappear within a day or two of being moved to fresh air.<ref name=hsdb />

Most cases of polymer fume fever in humans occur due to smoking PTFE-contaminated tobacco,<ref name=hsdb /> although cases have occurred in people who have [[welding|welded]] near PTFE components.<ref name=hsdb /> PTFE-coated cookware is unlikely to reach dangerous temperatures with normal use, as meat is usually fried between {{convert|204 and 232|C}}, and most [[cooking oil]]s (except refined [[safflower oil|safflower]] and [[avocado oil|avocado]] oils) start to [[smoke point|smoke]] before a temperature of {{convert|260|C|F}} is reached. A 1973 study by DuPont's Haskell Laboratory found that a 4-hour exposure to the fumes emitted by PTFE cookware heated to {{convert|280|C}} was lethal for [[parakeets]], although that was a higher temperature than the {{convert|260|C|F}} required for fumes from pyrolyzed butter to be lethal to the birds.<ref>{{cite journal |last1=Griffith |first1=Franklin D. |last2=Stephens |first2=Susan S. |last3=Tayfun |first3=Figen O. |title=Exposure of Japanese Quail and Parakeets to the Pyrolysis Products of Fry Pans Coated with Teflon® and Common Cooking Oils |journal=American Industrial Hygiene Association Journal |date=April 1973 |volume=34 |issue=4 |pages=176–178 |doi=10.1080/0002889738506828|pmid=4723395 }}</ref>

[[Perfluorooctanoic acid]] (PFOA), a chemical formerly used in the manufacture of PTFE products such as non-stick coated cookware, can be [[carcinogen]]ic for people who are exposed to it (see [[#Ecotoxicity|Ecotoxicity]]).<ref name=cancer>{{cite web |title=Perfluorooctanoic Acid (PFOA), Teflon, and Related Chemicals |url=https://www.cancer.org/cancer/cancer-causes/teflon-and-perfluorooctanoic-acid-pfoa.html |website=www.cancer.org |access-date=4 April 2022 |language=en}}</ref> Concerning levels of PFOA have been found in the blood of people who work in or live near factories where the chemical is used, and in people regularly exposed to PFOA-containing products such as some [[ski wax]]es and stain-resistant fabric coatings, but non-stick cookware was not found to be a major source of exposure, as the PFOA is burned off during the manufacturing process and not present in the finished product.<ref name=hsdb /> Non-stick coated cookware has not been manufactured using PFOA since 2013,<ref>{{cite web|title=The truth about teflon: are non-stick pans safe?|url=https://www.bhg.com.au/the-truth-about-teflon-are-non-stick-pans-safe|access-date=2020-06-11|website=Better Homes and Gardens|date=2 October 2019 |language=en-us}}</ref> and PFOA is no longer being made in the United States.<ref name=cancer />