An act of kindness toward some wild cats backfired for some St. Joseph residents Saturday morning.

Authorities say a woman left an electric blanket outside overnight, and folded it.

Those are two things you should never do with an electric blanket.

St Joseph Fire Inspector Steve Henrichson says there is an electric mesh inside those blankets, and when you fold them, it can spark a fire.

“It creates what we call a ‘heat sink’ or ‘hot spot,’ and ignites the surrounding material,” Henrichson said.

Such blankets are not intended for outside use either. Henrichson says the plugs and control units are not built for the weather.

Investigators believe the blanket shorted out and ignited some nearby chemicals for the family’s swimming pool. The fire burned a deck and melted some siding off the house.

There were no injuries in the fire at 4505 Llama Lane Saturday morning.