Multiple killed as huge blast rips through Tennessee military explosives plant

• Agencies, including FBI, ATF, probing cause of explosion.
• Aerial footage shows debris and ashes across site.
• Company makes military,  demolition explosives.

Multiple people are dead and several others are unaccounted for after a blast in Tennessee at a military explosives company, CNN and other media outlets reported on Friday, citing local officials.

The explosion at Accurate Energetic Systems, about 50 miles (80 km) west of Nashville, occurred at 7:45am local time (1245 GMT), Humphreys County Sheriff Chris Davis told a press conference.

Davis said there were multiple fatalities, but it was still too early to know precisely how many people had perished, saying it was still possible there were some survivors.

When asked to describe the building where the blast occurred, Davis said, "There's nothing to describe. It's gone."

Investigators from the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives were at the scene working to determine the cause of the explosion, Davis said.

Aerial video on CNN showed what appeared to be the footprint of where a building once stood. 

In an adjacent parking lot, debris and what appeared to be ashes were scattered among a few parked vehicles.

Efforts to contact the company were unsuccessful.

Accurate Energetic Systems develops, manufactures and stores explosives for "military, aerospace, and commercial demolition markets," according to the company's website. 

The 1,300-acre headquarters in Bucksnort, Tennessee, includes eight production buildings and a quality lab.

Hickman County Mayor Jim Bates told CNN that the plant did not have a history of safety problems, although a small ammunition explosion occurred there in 2014. 

That incident killed one person and injured three, according to The Tennessean newspaper.