The blast in rural Tennessee that leveled an explosives plant and was felt for miles around left no survivors, authorities said Saturday.

Humphreys County Sheriff Chris Davis said during a news conference that officials were working on the assumption that all of the people at the site were dead. The total number of people who died was unclear, as was the cause of the blast.

Davis had said earlier there were 18 people missing.

“We’ve recovered no survivors,” Davis said.

The explosion Friday morning at Accurate Energetic Systems, which supplies and researches explosives for the military, scattered debris over at least a half-mile (800-meter) area and was felt by residents more than 15 miles (24 kilometers) away, Davis said.

Aerial footage showed the company’s hilltop location smoldering and smoky Friday, with just a mass of twisted metal, burned-out shells of cars and an array of debris left behind.

Davis, who described it as one of the worst scenes he’s ever seen, said officials were investigating the site and still working to recover those who were killed.

“It’s not like working an accident. It’s not like working a tornado. We’re dealing with explosions. And I would say at this time, we’re dealing with remains,” he said.

At times becoming apparently emotional, Davis said there has been an outpouring of support for the community, located in a heavily wooded area of middle Tennessee, between the economically vital Tennessee River and the bustling metropolis of Nashville.

AP video shot by: Obed Lamy