An explosion at a Tennessee military munitions plant left multiple people dead and missing on Friday, authorities said, as secondary blasts forced rescuers to keep their distance from the burning field of debris.

The blast, which people reported hearing and feeling miles away, occurred at Accurate Energetic Systems in rural Tennessee. The company’s website says it makes and tests explosives at an eight-building facility that sprawls across wooded hills near Bucksnort, a town about 60 miles (97 kilometers) southwest of Nashville.

“We do have several people at this time unaccounted for. We are trying to be mindful of families and that situation,” Humphreys County Sheriff Chris Davis said at a news conference. “We do have some that are deceased.”

BBC Watch: Aerial footage shows devastation after blast at Tennessee plant