The fire that damaged a storage unit and sent two firefighters to the hospital was believed to be started by chemicals, according to county emergency officials.

Cayuga County Emergency Management Director Brian Dahl said Friday that investigators believe a rag soaked in acetone spontaneously combusted and caused the fire.

Emergency authorities received a report of smoke coming from a storage shed early Friday morning. The shed contained 18 drums filled with acetone, one of which ruptured, authorities reported.

Officials from the county Department of Health and the state Department of Environmental Conservation investigated the scene. The spilled chemicals were contained, and nothing harmful was released into the environment, according to the DEC.

Acetone is a flammable solvent most commonly used in nail polish remover and paint thinner.

Two firefighters were transported to Auburn Memorial Hospital for exhaustion, and they were both released later that day, Dahl said.

The fire took place at the Upsco manufacturing plant, though it only damaged the storage container. Upsco makes and refurbishes meters for the utility industry.