SPOKANE VALLEY -

A Spokane Valley Fire investigator confirmed through some simple tests that heating hand towels in microwaves have been the catalyst for two recent house fires.

On Thursday fire investigator Rick Freier spent his morning confirming whether or not a cotton towel, heated in a microwave, could start a fire.

?In my five years I've never seen one of those,? Freier said.

That is until Wednesday when he saw not one but two fires started by towels heated in microwaves. In one case a resident living in a home on East Main told investigators he had a sore shoulder and warmed up a towel in the microwave to ease the pain. He put it in for one minute and then set it outside because it smelled funny.

Eight hours later the towel set his back deck on fire.

In another case an elderly woman put a towel in the microwave to heat a sore back. The towel caught fire and she put the fire out in the sink before it caught her house on fire.

?Having two in twelve hours, something might be up, lets check it out, so here we are today,? Freier said.

He started his test with a wet towel. After more than six minutes in the microwave it steamed but didn't scorch.

?We?re going to go with a dry towel on the center and a damp towel on the outside,? he said.

In the second test the center of the damp towel started to burn after three minutes. After five minutes the internal temperature was 600 degrees.

?When you put a dry towel or a towel that's only wet on the surface this is what you?re getting on the inside,? he said.

For his final test Freier tried a dry towel. It took only a matter of seconds for it to start smoldering and it kept smoldering for another 15 minutes after taking it out of the microwave.

?We proved a theory today and I hope people realize you can't put anything dry in the microwave,? he said.

?The big thing here is if the doc is telling you to use a warm compress and he tells you to use the microwave make sure it's wet all the way through.?