SIOUX CITY, Iowa (KCAU) — Sioux City Fire Rescue has revealed the causes of fires at two Sioux City businesses.

According to a release from SCFR, the fires at Opa Time and Pierce Street Laundry were caused by the spontaneous combustion of rags that were used to clean oil.

Investigators said that they came to the conclusion while analyzing video surveillance and physical evidence gathered at the scenes.

SCFR said that if your business uses cooking oils, you should store used rags and towels in a non-combustible container with a closed top until they can be discarded or washed properly. If laundered, fabric cloths that were used to clean oils should be promptly removed from the dryer and laid to cool.