Microwave oven fire safety


Microwave ovens emit radiation that will excite water molecules and if there is no moisture available, other less volatile molecules will absorb the radiation and start to heat. Therefore any material which has dried out can overheat and ignite in a microwave oven. Also, any metal objects inside a microwave can cause severe sparking which could lead to a fire.

Fire and Rescue NSW recommends these simple fire safety tips when using microwave ovens.

  • Before using a new microwave oven, always follow the manufacturer's installation and operating instructions and safety precautions.
  • To minimise the risk of fire, never attempt to heat articles that are not approved for use in microwave ovens.
  • Do not use metal, metal edged bowls, metal foil or even twist ties in microwave ovens. The metal can cause arcing which can lead to a fire.
  • Never attempt to dry or sterilise clothes or blankets in microwave ovens as a fire may result when the items are removed from the oven.
  • Clean the microwave oven regularly, this will reduce fire potential. Clean the oven cavity and the outer edge of the cavity. Always unplug the oven when cleaning.
  • Never use recycled paper in microwave ovens unless they are specifically approved for microwave use. Recycled products including paper towels have minute metal flecks; these can cause sparks and even flames.
  • Only use microwave-safe utensils. The instructions for the microwave oven often specify what types of containers etc are safe to use for that appliance.
  • When cooking popcorn heat according to the instructions, begin with the minimum time specified as some microwaves can scorch popcorn in as little as two minutes.
  • Heating of wheat bags has a fire risk, never heat longer than manufacturer's instructions and never more than a maximum of 3 minutes, adding oils to wheat bags increases the fire risk. Home made wheat bags have a higher risk. Continual heating and drying of wheat bags increases the risk. Adding a cup of water in the microwave should decrease the risk. Click here to view the wheat bag fire safety fact sheet.
  • Never heat flammable or combustible liquids in the microwave - a fire or explosion may occur.
  • Be extremely careful when removing heated liquids and food from the microwave, the container may only feel warm but the contents are extremely hot. Many scald burns have resulted from the removal of liquids and foodstuffs from the microwave, especially when used by children. Allow the food or liquid to sit for 60 seconds before removing. Be careful of steam escaping when removing wrappers.
  • If you have a fire in the microwave oven, turn off the oven immediately and unplug the power cord if safe to do so. Do not open the door of the microwave, simply wait till the fire suffocates, never open the door until you are absolutely sure the fire is out. Dial Triple Zero (000) and ask for Fire.

In an Emergency Call Triple Zero (000)

A collaboration of the Fire and Rescue NSW, NSW Rural Fire Service, ACT Fire Brigade and ACT Rural Fire Service