Several dead and missing after explosion at Tennessee munitions plant, sheriff says

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

The explosion, which people reported hearing and feeling miles away, occurred at Accurate Energetic Systems in 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 97 kilometres southwest of the state capital, 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."

The cause of the explosion was not immediately known and Davis said the investigation could take days.

Aerial footage of the aftermath by WTVF-TV showed the explosion had apparently obliterated one of the facility’s hilltop buildings, leaving only smouldering wreckage and the burnt-out shells of vehicles.

The sheriff added that although the scene was secure from large explosions, smaller ones may still be heard.

Emergency crews were initially unable to enter the plant because of continuing detonations, Hickman County Advanced EMT David Stewart said by phone. He didn’t have any details on casualties.

Accurate Energetic Systems, based in nearby McEwan, did not immediately respond to press enquiries for comment.

"This is a tragedy for our community," McEwen Mayor Brad Rachford said in an email. He referred further comment to a county official.

Residents in Lobelville, a 20-minute drive from the scene, said they felt their homes shake and some people captured the loud boom of the explosion on their home cameras.

State Representative Jody Barrett, a Republican from the neighbouring town Dickson, said he was worried about the possible economic impact because the plant is a key employer in the area.

"We live probably 15 miles as the crow flies and we absolutely heard it at the house," Barrett said. "It sounded like something going through the roof of our house."

The Tennessee Emergency Management Agency confirmed there were injuries but wasn’t sharing any numbers because the Department of Health hasn't confirmed them, spokesperson Kristin Coulter said by telephone.