If you heat non-stick cookware to high temperatures, it gives off fumes that contain chemicals that are harmful to your health. Some studies show that heating non-stick coatings to 300°C (572°F) can create fumes containing TFE – a possible cancer-causing substance.
You may also be exposed to the chemicals used to make non-stick cookware because these substances are released into the environment during the manufacturing process. This may be of greater concern for people who work in places that make products with non-stick coatings, but scientists have also found increasing levels of PFOA in areas far from the manufacturing plants. Research shows that PFOA is persistent in the environment and that most of the population has been exposed to low levels of the chemical.
Though non-stick coating can sometimes flake off into your food, there is no evidence that eating these small quantities is harmful.