Teflon is composed of a chemical called polytetrafluoroethylene. When this chemical sits at room temperature, it has no negative effects. It is only when it is heated to temperatures above 200 degrees when it starts to become toxic, as it contains carcinogens that become airborne and leach into food. Many manufacturers have stopped using this substance since around 2015 and began searching for safer ways to cook on a non-stick surface, and that’s how ceramic coated cookware was born.