What Are the Dangers of Microwave Oven Use?

Radiation Concerns

• The housing and seal of a microwave oven are designed to keep the low levels of radiation used to warm the food safely inside of the machine. In addition, standard manufacturing practices ensure that the microwave automatically shuts off when the door is opened. The amount of electromagnetic radiation that microwaves use is very small, well below harmful levels, and radiation leakage is rare as long as the oven is undamaged. Still, the farther away you stand from the microwave, the lower your exposure is to possible leakage. Standing an arm's length away from your microwave reduces your exposure dramatically just as moving away from a live flame reduces your exposure to the heat.

Chemical Migration from Plastics

• Many plastic containers are labeled as safe for use in microwave ovens; however, not all plastics can withstand microwave energy. Some can allow chemicals to leach into foods. The concern involves the possible release of diethylhexyl adipate (DEHA), a chemical used to make plastics, into foods in very small amounts. The Food and Drug Administration does not consider this leakage to be dangerous, but some people prefer to use glass or ceramic plates as an alternative to reheating foods in plastic containers. While plastic wrap helps food retain moisture and prevents splattering within the microwave oven, foods should be covered only loosely with plastic wrap, with an inch or so left between the food and the wrap.

Superheating

• Plastic containers that have not been certified as microwave-safe, such as take-out food containers, can warp and melt, causing burns to the user when the food is removed from the oven. In addition, liquids can reach temperatures far above their boiling point if they are heated for longer than necessary in a microwave oven. This causes a buildup of excess steam under the surface of the liquid which can erupt when another substance is added; for example, when a teaspoon of coffee or a tea bag is added to superheated water.

Undercooking

• While the radiant heat used by conventional ovens allows the food to cook through, microwaves cook food by heating the water molecules in the food to a depth of about an inch. Food should be stirred and rotated when cooked in a microwave to ensure that it has reached a temperature hot enough to kill bacteria. This is why some microwave-ready meal packages recommend leaving foods in the oven for a few minutes after the oven is turned off, as it allows the food to continue cooking while the molecules are still in motion.