A nonstick skillet is perfectly safe to use at temperatures below 500 degrees Fahrenheit. Once the pan reaches a temperature higher than that, the nonstick coating begins to break down, and can leach into food. At temperatures above 600 degrees, the pan can produce dangerous, toxic fumes. Be aware of the temperature of the pan. You should never preheat an empty pan or cook over high heat.
Anytime you are cooking with a nonstick pan, be sure your kitchen is properly ventilated. Open a window or turn on your exhaust fan to clear fumes that may be produced.
According to research conducted by the Good Housekeeping Test Kitchen, heavier nonstick skillets are safer than their lighter counterparts. The heavier pans took longer to heat, making it easier to stay under the 500-degree threshhold.
According to the Good Housekeeping report, swallowing a piece of nonstick coating from a chipped pan will probably not harm you. However, chipped pans are more likely to leach toxic compounds. Avoid metal utensils, and put a paper towel between stacked pans to prevent chips and scratches in the cabinet. Never clean your skillet with steel wool.
Nonstick skillets are designed to last anywhere from three to five years with moderate usage. However, to be on the safe side, anytime a skillet becomes damaged, you should throw it out.