Some microwaves could be turning on by themselves and catching fire, according to a Consumer Reports investigation.

Joe Lyons is one of 10 residents in a Seattle condo building who have had problems with their KitchenAid microwaves.

According to the condo board, the microwaves started on their own. In at least one case it caused sparks in the electrical circuit.  

At another development in Florida, a fire started in a microwave that was not in use, according to the official fire report. Both of those incidents, reported to the Consumer Product Safety Commission, involved the same microwave -- the KitchenAid KHMS155LSS.

A Consumer Reports investigation looked at thousands of pages of CPSC documents in its investigation of appliance fires, including many obtained through Freedom of Information Act requests.

More than 40 of the CPSC reports involved KitchenAid microwaves that turned on by themselves, some causing fires. Whirlpool, which owns KitchenAid, says it has not been able to verify a single report of a self-starting microwave.

Consumer Reports also examined 82 similar reports involving some GE microwaves, six of which involved serious fires. The reports listed various models, but 30 complaints involved the GE Spacemaker line of over-the-range microwaves. GE told Consumer Reports that it "has investigated unverified reports of 'self-start' and found them to constitute product quality, not product safety, concerns. Many have been determined not to be 'self-starts' at all."

None of those microwaves has been recalled. And the problem is not limited to those two manufacturers. The Consumer Product Safety Commission told Consumer Reports it has "an open investigation into the safety of kitchen appliances, including microwaves."
There were five microwave fires in Vancouver in 2012. Four of them were attributed to human error, while the other microwave fire was an electrical problem that took place when no one was at home.

"Anybody who has any issues with any appliances in their home, particularly appliances that create heat, if you're having an issue with it, first of all unplug it. Take away the source of energy," said Vancouver Fire Captain Gabe Roder.

It's also a good idea to know which circuit breaker turns off the microwave in case of an emergency. If you're experiencing a problem with a microwave or any appliance, Consumer Reports recommends notifying the manufacturer immediately.