While it's extremely common and relatively safe to use paper towels in the microwave it is indeed possible for your paper towel to catch fire in the microwave.
I have been able to show through my own experiments with paper towel, paper, cardboard and paper plates that there are certain conditions that cause them to catch fire in the microwave.
Your paper towel likely caught on fire in the microwave because it was in there so long it was able to get hot enough to combust and burn. Paper ignites around 480ºF (248ºC) and microwaves can make paper towels hotter than this. Scrunched up or folded paper towels are more likely to catch on fire than if you lay them out flat.
I have personally set paper towels on fire in my microwave, but I have also done a bunch of tests and research to work out how to safely use them and when they are more likely to burn.
Can Paper Towels Catch on Fire In The Microwave?
Given enough time and given the right conditions all type of paper towels can catch on fire in the microwave, even ones that are pure white.
I've seen some comments online saying that some paper towels are microwave safe while other paper towels have little pieces of metal in them or types of ink that makes them potentially catch on fire.
While these may make the paper towel more likely to catch on fire even plain white paper towels are able to catch on fire in the microwave.
Microwave ovens produce microwaves which cause the molecules in your food, drink and yes your paper towels to vibrate which creates heat.
When a paper towel is lying flat in the microwave on top of or under your food the heat dissipates across the paper towel. However, when the paper towel is folded or scrunched up this heat can build up enough to set the paper towel on fire.
You can see it happening in my paper towel experiment below and you can view more details on my article can you microwave paper towels:
How To Safely Use Paper Towels In The Microwave
There are a couple of key tips to safely use paper towels in the microwave. Follow these steps and you should avoid the smoke and flames that come with a paper towel that has caught on fire.
Lie The Paper Towel Flat
Lying the paper towel relatively flat across the top of your food or on the bottom of your food decrease the chances of it catching on fire.
Heat is not able to as easily build up and the paper towel is less likely to burn.
Scrunched up paper towels are highly likely to smolder, smoke and eventually burst into flames. So avoid using scrunched up paper towels in the microwave at all.
Microwave In Spurts of 1-2 Minutes
While a paper towel can build up a lot of heat in the microwave that heat dissipates extremely quickly as soon as the microwave is turned off.
Heating your food and paper towel for spurts of 1-2 minutes and then giving your paper towel 15-30 seconds to cool before putting back in the microwave can reduce the chances of it catching on fire.
Wet The Paper Towel
Wetting the paper towel can serve a few purposes. It can stop the paper towel from blowing off your food or drink due to steam pressure, it can help keep your food moist and stop it from drying out.
PLUS a wet paper towel is less likely to catch on fire than a dry paper towel.
Is it still possible for a wet paper towel to catch on fire in the microwave? Look it probably is given enough time and the right conditions, but it's much less likely to erupt into flames when compared to a dry paper towel.
Put Your Paper Towel In With Food/Drink
Food and drink will absorb a lot of the microwave energy, leaving less energy to heat up the paper towel and set it on fire.
A paper towel in a microwave by itself will absorb a lot more microwave energy and get hotter faster.
Watch It Closely
Watch your food and paper towel in the microwave closely and if you start to see or smell smoke then turn off your microwave immediately and inspect it.
When I did my experiments the paper towel started smoking about 1 minute into microwaving and it took nearly a full minute more to catch on fire.
Turning my microwave off when I smelled smoke would have avoided the paper towel catching on fire.
What To Do If Your Paper Towel Catches On Fire In The Microwave
Maybe you're one of the unlucky people and your paper towel does catch on fire in the microwave. Hopefully you were watching closely and are able to act quickly.
If your paper towel does catch on fire in the microwave here's what you should do.
Stop The Microwave Immediately
Obviously you should stop the microwave immediately.
A paper towel on fire in an active microwave will cause a lot more damage than when the microwave is turned off.
So if you see flames, instantly stop your microwave.
Put Out The Fire
Once the microwave is turned off you want to put out the fire as quickly as possbile.
Use water to put out the fire, unless you are concerned about an oil fire.
If you have your paper towel in the microwave with something extremely oily then water may spread the fire so be careful.
With the microwave off the fire will likely put itself out pretty quickly as paper towels don't contain a lot of combustible material. Plus microwaves have limited air and thus limited oxygen. Once your fire burns through the available oxygen in the microwave it should go out by itself.
But it's better to take action than to just leave it hoping it will go out.
Start The Clean Up Process
Once you've put out the fire you'll want to take your microwave outside so the smoke doesn't set off your alarm or stink out your house.
You'll then want to start the clean up process.
Carefully remove the charred remains of your paper towel and any other objects that have caught on fire.
Remove the rotating plate and then get to work scrubbing and cleaning your microwave. I'll do a full article on exactly how to clean a burned microwave in the future.