• Not all plastic is safe for the microwave.Wrapped salmon steaks on a plastic tray image by L. Shat from Fotolia.com
  
  Not all plastic is safe for the microwave. No plastic will damage your microwave oven, but certain plastics contain phthalates or bisphenol A (BPA), which can leach into food when heated. When eaten, these substances can disrupt the endocrine system, increasing risk for certain cancers, diabetes and early puberty. To minimize risk, use non-plastic dishes in the microwave. When that's not possible, only use microwave-safe plastics.
  
  

Microwave-safe Plastics

• If the plastic container, plastic tableware or the packaging it came in is marked "microwave safe," then it is safe to put in the microwave. If you do not have the original packaging, or the original label has worn off, check the manufacturer's website. Good Housekeeping magazine tested 30 different plastic containers, including ones purchased at discount stores. Only three contained phthalates or BPA and foods microwaved in those containers didn't contain any phthalates or BPA.
  
  

Plastic Wrap

• It's safe to put plastic wrap in the microwave if the packaging says so, but experts recommend not letting the plastic wrap touch the food directly when microwaving. Direct contact with hot food can cause the plastic wrap to melt into the food. Consider covering food with wax paper or plain white paper towels, which are microwave-safe and don't contain phthalates or BPA.
  
  

Plastic Trays

• The plastic trays that come with frozen entrees are safe to put in the microwave once. They are not made to be microwaved multiple times and should not be re-used. Plastic trays that come with fresh meat or fish are not microwave-safe.
  
  

Non-microwave-safe Plastics

• The plastic containers that restaurants use for soups and hot food are not safe for the microwave, even once. Margarine tubs, yogurt containers and other plastic containers that hold food purchased at the supermarket are not microwave-safe. These plastics get soft and break down in the microwave. If a container begins to melt in the microwave, discard the food in it along with with the container. If food that was microwaved in a plastic container smells or tastes unusual, throw out both the container and the food.