Why Microwaves Can Catch Fire—And How to Use Yours Safely

just about any appliance that cooks food can spew smoke or catch arouse, and barely anyone blames their cooktops or ovens or toasters for these kitchen mishaps. But when a microwave trip or smolders, it seems to inspire a deeper sense of awful and apprehension. actually, microwaves are among the safest cook appliances you can own. If they do start to burn, it ’ south normally for the lapp reasons as any other electric oven. ( Well, a microwave is the entirely appliance where you can by chance make something like ball lightning, but that ’ s not such a big deal, as it turns out. ) here ’ s what you need to know .

Overheated food or packaging is the main culprit

According to Bob Schiffmann, a 50-year veteran of the microwave diligence and president of the International Microwave Power Institute, 1 microwave fires normally start for the lapp cause that oven or stovetop or grill fires do : “ It ’ s simply due to [ the food ] overheat. ”

Food-based fires in a microwave about always happen because person overestimated or mis-entered the fudge time. An extra three minutes can be the deviation between a nicely baked potato and a char, smoky mess. Blasting a lean Cuisine that you think is freeze but is actually closer to room temp could cause problems, besides. Another perpetrator can be packaging that gets stuck near the wave emitter on the side of the machine—like a big bag of popcorn that gets wedged against the walls of a modest oven as the kernels expand. Schiffmann said that food-based fires like these “ create a bunch of smoke, but they tend not to be all that dangerous because the components can ’ t truly catch fire. ” If you spot smoke or fire in the oven cavity, turn off or unplug the microwave, but leave the door closed. UL-certified microwaves ( which is about all of them ) are designed to contain modest fires started by coarse foods ( like popcorn or potatoes ), so it should be safe to leave a microwave alone while the flames suffocate .

Other types of fires aren’t as common

Schiffmann said that he knows of three early ways that dangerous microwave fires can begin : 1 ) The world power supply can short out and burn the components inside the caparison ( it ’ s a risk with any electrical equipment ) ; 2 ) A power billow can trick the microwave into turning on, and it may run continuously until person notices and turns it off ( there are reports of this happening with several brands ) ; 3 ) Some share of the oven could be prone to catching fire when overheated ( like these Whirlpool models ). Microwaves have built-in safety features to reduce the chances and badness of these types of fires. They don ’ thymine seem to be closely american samoa common as food-based fires, either : A spokesperson from the National Fire Protection Association told us that 17 percentage of microwave fires begin in the appliance housing ( which is consistent with non-food fires ). But there ’ south constantly a hazard, and it ’ s authoritative to follow the condom advice in the manual to try to prevent any of these from happening. unfortunately, you won ’ thyroxine know whether your microwave is particularly susceptible to these types of fires until you see it happen or there ’ s a class-action lawsuit and hark back .

Sparks can happen, and you don’t really need to worry about them

Zaps and sparks inside the oven pit aren ’ t a sign of a microwave malfunction, nor are they specially dangerous, according to Aaron Slepkov, a physics professor at Trent University in Ontario. Sparks happen because the waves of energy that should get absorbed by your food alternatively bounce around between objects. The energy gets concentrated in a minor space, so it ’ randomness prone to react with something in the air or food, creating a spark.

metallic with uncut or pointy edges, like a crotch or ball of aluminum foil, will about always spark. Paper towels made from recycle materials can besides ( unintentionally ) incorporate flecks of metallic element that might spark, according to the National Institutes of Health. It ’ s not a stretch to imagine that some food box might besides contain hide metallic element. Non-microwave-safe bowling ball and plates might crackle or spark besides. And in the right conditions, food can besides create sparks. Grapes are the best-known perpetrator ( video recording ), and Slepkov co-authored a newspaper that got to the bed of this phenomenon ( his lab nicknamed the visualize “ Grape Balls of Fire ” ). Grapes have the ideal size and moisture content for sparking, but it can happen with peas, blueberries, and other foods a well. If you do see sparks inside the oven cavity, it ’ mho nothing to be excessively implicated about—they ’ re like fireworks for nerds. Microwave sparks are a plasma, the fourth state of topic, that ’ s much rare on land than natural gas, liquids, or solids. Plasma feeds off of microwave energy, according to Slepkov, and if you glance up at the acme of the oven cavity after you see the initial sparks, you might see plasma dancing about for the duration of the cook meter. “ literally, it ’ s musket ball lightning, ” Slepkov said ( though some experts contend it ’ s not quite the same thing ). Given enough time and trip, the plasma could char the top of your oven, and reflected microwaves could damage the magnetron ( the oven ’ s congress of racial equality component, which generates the waves that heat your food ). But the risk of an hell is small, according to Slepkov. The plasma won ’ metric ton burn your food, because it floats to the top of the cavity. “ It ’ s not going to explode your microwave or anything. And if it does damage your microwave, it will only damage your microwave in a means that will immediately stop feed this plasma. ”

Microwaves are quite safe, as far as cooking appliances go

One fire is besides many, but the numbers suggest that microwaves are quite safe. Estimates can vary, but at least 90 percentage of US households have a microwave. According to the National Fire Protection Association, microwaves cause 4 percentage of cooking-related house fires per class ( PDF ) and 1 percentage of consociate deaths. A like share of homes have a range or cooktop, so far those appliances account for 62 percentage of cooking fires and a whopping 89 percentage of the deaths. It ’ mho still wise to stay near your microwave while it ’ sulfur guide, so you can try to stop minor fires before they turn into big blazes. But of all the safety hazards in your kitchen, microwaves aren ’ t near the top of the list.

For more, check out our usher to the best microwaves .


1. Bob Schiffmann holds patents in microwave technology and does consulting work for microwave-adjacent companies, but he does not represent any manufacturers directly, nor is he paid by them. The International Microwave Power Institute is a membership industry group.
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