A blast in rural Tennessee that leveled an explosives plant and was felt for miles around killed 16 people and left no survivors, authorities said.

The explosion left a smouldering wreck of twisted and charred metal and burned-out vehicles at the Accurate Energetic Systems plant, which supplies and researches explosives for the military.

The cause of the blast is not known. Investigators are combing the incinerated property foot-by-foot searching for possible evidence.

State officials brought in a “rapid DNA” team to help identify the remains of people recovered at the site.

Humphreys County Sheriff Chris Davis said about 300 responders are working "foot by foot” as they deal with explosive material that has been damaged and remains volatile. An ambulance and a helicopter used for air evacuations were brought in, for the safety of first responders.

Guy McCormick, a supervisory special agent with the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives, said explosive specialists and bomb technicians are trying to make the area safe for national ATF investigators. He said the nature of the scene can change because of the heat and pressure caused by the explosion.

Davis said it could be days, weeks or even months before foul play is ruled out.

The site is located in a heavily wooded area of middle Tennessee, between the economically vital Tennessee River to the west and the bustling metropolis of Nashville to the east.

Officials at an evening news conference said counselors would be available for grieving students on Monday.

The company’s website says it processes explosives and ammunition at an eight-building facility that sprawls across wooded hills in the Bucksnort area, about 60 miles (97 kilometers) southwest of Nashville. It is not immediately known how many people work at the plant or how many were there when the explosion happened.

Accurate Energetic Systems, based in nearby McEwen, said in a post on social media on Friday that the company's “thoughts and prayers" are with the families and community impacted.

“We extend our gratitude to all first responders who continue to work tirelessly under difficult conditions,” the post said.

The company has been awarded numerous military contracts, largely by the U.S. Army and Navy, to supply different types of munitions and explosives, according to public records. The products range from bulk explosives to landmines and small breaching charges, including C4.

When the explosion occurred, 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.

The U.S. has a long history of deadly accidents at workplaces, including the Monongah coal mine explosion that killed 362 men and boys in West Virginia in 1907. Several high-profile industrial accidents in the 1960s helped lead President Richard Nixon to sign a law creating the Occupational Safety and Health Administration the next year.

In 2019, Accurate Energetic Systems faced several small fines from the U.S. Department of Labor for violations of policies meant to protect workers from exposure to hazardous chemicals, radiation and other irritants, according to citations from OSHA.

In 2014, an explosion occurred at another ammunition facility in the same small community, killing one person and injuring at least three others.