The fire erupted in an art supply store on 22nd Street. But when firefighters arrived on the scene, the smoke and flames were too intense so they went around the corner to a drug store on 23rd Street to fight the fire. Twelve firefighters were killed when the floor collapsed into the cellar. The store where the fire first erupted, it was later discovered, had expanded its basement storage area into the drug store's basement and moved a crucial load bearing wall.