The FDA has received reports of serious skin burns or scalding injuries around people's hands and faces as a result of hot water erupting out of a cup after it had been over-heated in a microwave oven. Over-heating of water in a cup can result in superheated water (past its boiling temperature) without appearing to boil.
This type of phenomena occurs if water is heated in a clean cup. If foreign materials such as instant coffee or sugar are added before heating, the risk is greatly reduced. If superheating has occurred, a slight disturbance or movement such as picking up the cup, or pouring in a spoon full of instant coffee, may result in a violent eruption with the boiling water exploding out of the cup.
What Can Consumers Do to Avoid Super-Heated Water?
- Follow the precautions and recommendations found in the microwave oven instruction manuals, specifically the heating time.
- Do not use excessive amounts of time when heating water or liquids in the microwave oven.
- Determine the best time setting to heat the water just to the desired temperature and use that time setting regularly.