Several firefighters were treated for heat exhaustion at a fire that destroyed an Eliot barn Saturday.

Eliot Fire Chief Jay Muzeroll said that the cause of the blaze on Old Farm Road will be investigated by his department and the State Fire Marshal’s Office but may never be known because of the extent of the damage. He said the cause is not suspicious.

About 30 firefighters from Eliot and surrounding departments responded to the fire at 4:36 p.m. in humid conditions with temperatures in the mid- to high 80s. One firefighter was taken to York Hospital for observation.

A boat and tools were destroyed in the fire. The were no animals in the barn, Muzeroll said.