INDIANAPOLIS (AP) — Indiana's top firefighter is urging Hoosiers to be careful if they're heating their homes with space heaters or other alternative methods.

State Fire Marshal Jim Greeson says alternative heating sources are one of the leading causes of house fires, accounting for nearly one-fifth of the nation's home fire deaths each year.

Greeson says that if they can, Indiana residents should avoid using space heaters and other alternative heating methods.

But if that's not possible he says they should follow specific safety protocols to avoid a potentially deadly house fire.

Those protocols include keeping space heaters away from anything that's flammable, such as clothing, curtains or furniture and making sure there's at least a three-foot perimeter around the portable heaters.

Space heaters should also never be left on in unoccupied rooms.