The National Guard says a bunker full of “clean-burning igniter” exploded at Camp Minden, where a company went bankrupt and abandoned about 160 tons of the substance and 7,800 tons of potentially explosive artillery propellant.

Authorities say nobody was hurt in Thursday morning’s blast. It occurred more than 6.5 miles from the site where a contractor is burning the M-6 propellant and will burn the remaining 100 tons of igniter.

Before they were able to get close to the site, Louisiana State Police had said a bunker of M-6 exploded.

State Trooper Matt Harris called Thursday’s explosion minimal compared to one in 2012 that touched off an investigation of Explo Systems Inc., which went bankrupt the following year.

Col. Ed Bush, spokesman for the national guard, said the area is safe. “That bunker system that’s out there did exactly what it’s supposed to do” — contain and control the explosion, he said.

Explosive Services International of Baton Rouge is operating a 24-hour burn operation at Camp Minden to destroy the propellant — used for firing heavy artillery — that was left behind when Explo Systems Inc. went bankrupt in 2013. The company says it has destroyed more than 3,100 tons.

The National Guard leases space to businesses at the nearly 15,000-acre base 22 miles east of Shreveport.

Webster Parish director of Homeland Security and Emergency Preparedness Jenny Reynolds said she was standing on front porch drinking coffee at 5 a.m. when she saw a flash and then heard an explosion from the direction of Camp Minden. Reynolds said there had been no reports of damage to other facilities at Camp Minden or the homes or buildings nearby.

Truck driver DaWayne Munk told Shreveport station KSLA-TV he was driving on Interstate 20 when he “saw a fireball over the tree line. The whole sky lit up.”

The National Weather Service says its radar picked up a column of smoke over the Camp Minden area.

Forecaster Mike Berry told The Associated Press the smoke appeared at 5:08 a.m. and disappeared from the radar 10 minutes later.

State Police began investigating the company in 2012 after an explosion in one of Explo’s leased bunkers shattered windows 4 miles away in Minden and created a 7,000-foot mushroom cloud. They found the M6 and clean-burning igniter, much of it in bags in the open. Authorities moved the bagged chemicals to 90 bunkers of M6 and three of igniter.

The owners and four officials of Explo Systems pleaded not guilty to federal charges earlier this month. They are accused of lying to get contracts to “demilitarize” the propellant, storing it unsafely and obstructing inspections.

This story has been corrected to reflect that the explosion happened in one of 61 bunkers where 7,800 tons of propellant is stored, and that police are now saying clean-burning igniter, not M6 propellant, exploded.