Flames engulfed two lumber storage areas at Batesville Casket on U.S. 61 South Wednesday night, keeping crews of firefighters at work until this morning.

The five-alarm fire broke out at about 8:35 p.m. in the storage areas, called blowboxes, where the sawed timber is dried by forced air before shipment to other Batesville locations.

The blaze was out of control for more than three hours, and four firefighters were treated on the scene for dehydration, Vicksburg Fire Chief Keith Rogers said, adding the source of ignition was a mystery.

The first blowbox was already in heavy flames when the first unit arrived, Rogers said. Firefighters blocked a second area from flames by using a water curtain between the two buildings. The response came from the nearby Vicksburg Municipal Airport station, other city stations and off-duty firefighters were also summoned. At least one unit remained on the scene at 6:30 this morning.

Flames could be seen more than a mile away, and smoke covered much of the city and South Warren County.

The Vicksburg Fire Department will coordinate the investigation into the cause of the fire with the state fire marshal’s office, Rogers said.

It is believed employees working at the time the fire broke out were on a break and not near the storage areas. No injuries to any employees were reported.

Plant manager Mark McDonald declined comment on the fire and losses, saying he was “concentrating on taking care of customers” this morning. No damage estimate was available.

Firefighters used company forklifts to save what could be salvaged from the second blowbox, Rogers said.

At midmorning, investigators from Vicksburg Fire Department, the state fire marshal’s office and the Bureau of Alcohol, Tobacco, Firearms, and Explosives were on the scene.

“This could take an hour, it could take weeks, depending on what we can find,” said Leslie Decareaux, an investigator with Vicksburg Fire Department.

Batesville Casket Company, founded 99 years ago and based in Batesville, Ind., is the United States’ largest casket manufacturer. The local plant accepts hardwoods and other timber and sends it to finishing plants in Batesville, Miss, and Nashua, N.H.

The Batesville plant here opened in 1980 and employs about 240 people at its 20-acre site. In the last five years, the company has invested about $4 million in expansions.

A December 2002 fire at the site was confined to a sawdust collection bin.