PFD stated the cause of the fire is believed to be from “oily rags used in floor staining ... disposing of such materials to prevent spontaneous combustion,” PFD shared.

Chief Investigator Adam Matzner said the fire was a result of the spontaneous combustion of oil grease rags, deeming it ...

The cause of the explosion was listed as unintentional “spontaneous combustion, chemical reaction ... When firefighters entered the building, they found rags still in an exploded extractor ...