An early-morning blaze and propane explosion at an ammunition factory in East Alton was contained to a maintenance shed and caused no injuries, according to police.

A motorist spotted fire in a maintenance shop at the Winchester Ammunition plant, which is a division of Olin Corp.,  and called 911 about 3:15 a.m., according to East Alton Fire Chief Randy Nelson.

Nelson said additional fire departments were called to assist in battling the blaze. The fire was inside the maintenance portion of the business that was quite a distance away from the ammunition plant's manufacturing area, he said. Several small propane cylinders inside the maintenance shed exploded.

The cause of the fire has not been determined and is under investigation, Nelson said. The maintenance building structure was a total loss.

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Denise Hollinshed is a reporter for the St. Louis Post-Dispatch