“We can assume that they are deceased at this time,” Humphreys County Sheriff Chris Davis told a news conference, referring to 18 people missing since the explosion Friday in the town of Bucksnort.

The factory owned by Accurate Energetic Systems made explosives for both military and demolition purposes.

The blast destroyed an entire building at the plant’s large campus, shook homes miles away and sent debris flying, news reports said.

Davis said DNA testing will be used to identify remains.

“But we’re going to have to slow-walk that because of the scene, the way that the scene is,” Davis said.

In a statement, the company called the blast “a tragic accident”.

But Davis said, “Can I say we’re going to rule out foul play? We can’t answer that. That might be days or weeks or months before we can do that.”

He said staff from several federal agencies, including the FBI have been sent to the blast site to help with the investigation.