An explosion happened early Thursday morning (Sept. 29) at Camp Minden in northwest Louisiana, according to Webster Parish police. It's the same site where Explo Systems Inc. was previously accused of abandoning 7,800 tons of potentially explosive artillery propellant. No injuries have been reported, police said. "Camp Minden leadership has and will continue to do accountability checks of personnel," Webster Parish authorities said in a Facebook post. "The incident area has been secured and at daylight a more in-depth investigation will take place with Webster, Bossier and state response agencies." Nearby Doyline High School is open, the parish said, adding that the explosion doesn't pose a direct threat to surrounding communities. Louisiana State Police say a hazardous materials unit is on the scene investigating after reports of the explosion started coming in at 5 a.m. Thursday. Truck driver DaWayne Munk told KSLA News 12 he witnessed the explosion while driving on Interstate 20 near mile marker 33. "I saw a fireball over the tree line," he said. "The whole sky lit up." The National Weather Service has since reported picking up a debris cloud on its radar, according to KSLA News. Explosive Services International of Baton Rouge is working at Camp Minden on the burn operation to destroy millions of pounds of improperly stored M-6 propellant. Company President Billy Poe told the Associated Press his men at the site didn't hear an explosion. He said his personnel are accounted for and no one is hurt. Poe said he is on his way to the scene and plans to get a helicopter in the air after daylight to check out the area where the propellant is being stored. The explosion comes a week after the owners and four officials of Explo Systems Inc. pleaded not guilty to federal charges. The trial date for the Explo Systems Inc. owners and executives will be set at a status conference scheduled Dec. 13, KSLA-TV reported. They are accused of lying to get contracts to "demilitarize" the M6 artillery propellant, storing it unsafely and obstructing inspections. Explo Systems left the M6 and 160 tons of clean-burning igniter at Camp Minden when it went bankrupt in 2013. Louisiana State Police had begun 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. The owners are David Perry Fincher of Burns, Tennessee, and David Alan Smith of Winchester, Kentucky. The officials, all from northwest Louisiana, are William Terry Wright of Bossier City, Charles Ferris Callihan of Shreveport, and Kenneth Wayne Lampkin and Lionel Wayne Koons both of Haughton. All six are charged with conspiracy. Callihan is also charged with one count of lying to a federal agency. The other five face six counts each of wire fraud and more than 20 counts each of making false statements. Attorneys for Fincher and Wright have said their clients will plead not guilty. Attorneys for Smith and Koons have not responded to requests for comment. It was not clear who represents Lampkin and Callihan.