Teflon is probably the biggest offender on this list — many people choose this non-stick material because it’s convenient and ubiquitous. It’s also the most dangerous.
The non-stick properties of Teflon cookware are achieved with a coating of PTFE (polytetrafluoroethylene), which is a plastic polymer that starts to leach toxins when heated above 572 degrees Fahrenheit. These toxic fumes lead to flu-like symptoms called polymer fume fever, informally known as Teflon flu. They’re not only dangerous to people, but they’re also fatal to pet birds, like parrots.
Another chemical compound found in Teflon cookware is PFOA (perfluorooctanoic acid), which has been linked to several types of cancer including breast, prostate, and ovarian cancer. While it’s believed that PFOA is present in Teflon products in such small amounts that it poses no risk to humans, it’s worth noting that it’s also found in many other everyday things. That’s why it’s best to limit your exposure to it wherever possible.
Other coated non-stick cookware might be PTFE and PFOA-free (such as granite), but it’s only safe to use while the coating is intact. The coating is thin and chips easily. Once chipped, all use of that cookware should be stopped immediately after.