SANDPOINT — There were no injuries reported after a Sandpoint house caught fire Monday, said Idaho State Fire Marshal Knute Sandahl. Fire officials said the fire was caused due to improperly disposed rags.

The fire was reported at roughly 7 a.m. Monday, Jan. 29, and when firefighters arrived on the scene, smoke was already pouring out the windows of the house, located on the corner of Boyer Avenue and Church Street. Crews quickly got to work and were able to distinguish the flames before the fire spread to any nearby buildings or residences, Sandahl said. No one was injured as the residence was undergoing renovations and had no occupants at the time of the fire.

“The interior of the house had severe fire damage,” the fire marshal said.

However, the house was not regarded as a total loss and crews believe the damage can be repaired.

The cause of the fire was deemed to be improperly disposed of rags that were used for staining wood — a substance that Sandahl said is highly flammable if not handled properly. These substances should be placed in a sealed container that restricts airflow to the substances. The rags, in this case, were thrown into a regular trash can.

Sandahl said staining liquids, as well as other common fluids such as regular cooking oil or nail polish, can get so hot during the decomposition process that they spontaneously combust — which is what happened at the Sandpoint home.

“When it decomposes, it creates heat and poof,” the marshal said. “The oils commonly used in oil-based paints and stains release heat as they dry. If the heat is not released in the air, it builds up. That is why a pile of oily rags can be dangerous. As the rags dry, the heat is trapped.”

Water-based finishes do not pose this risk as they are not made from the same chemicals, he said.

Sandahl said almost 2,000 house fires are caused each year by combustible liquids not being handled properly during do-it-yourself home improvement projects. An easy way to prevent combustion, the marshal said, is to not pile dirty rags and leave them inside on the ground. Always take rags outside and either hang them up or lie them flat on the ground, preferably weighed down so they cannot blow away or subsequently bunch up and once again begin heating up.

“Put dried rags in a metal container,” Sandahl advised. “Make sure the cover is tight. Fill the container with a water and detergent solution; this will break down the oils.”

Rags put in the washing machine should be washed two or three times before they are put in the dryer, he said, to ensure all the flammable materials have been completely removed before being put in a very hot environment where they could easily ignite.

Sandahl also recommended that individuals check with their town for how to properly dispose of oily rags so they do not end up potentially igniting in a landfill.