NEW ORLEANS — An arraignment is scheduled Sept. 19 for owners and officials of a company charged with conspiracy involving 7,800 tons of potentially explosive artillery propellant abandoned in 2013 at a Louisiana facility.

They’re accused of lying to get contracts to “demilitarize” quantities of M6 artillery propellant, storing it unsafely and obstructing inspections.

Attorneys Ron Miciotto, representing owner David Fincher of Burns, Tennessee, and Donald Hathaway Jr., representing vice president of operations William Terry Wright of Bossier City, Louisiana, say their clients are innocent.

“My client had not violated any laws & will be vindicated by a jury of his peers!” Miciotto said in an email. “Mr. Fincher is looking forward to his day in court.”

Explo Systems’ other owner, David Alan Smith, is from Winchester, Kentucky. All four officials are from northwest Louisiana.

All six are charged with criminal conspiracy in an indictment handed up Aug. 25 and unsealed Wednesday. The owners, Wright, and program manager Kenneth Wayne Lampkin and traffic control manager Lionel Wayne Koons, both of Haughton, each face six counts of wire fraud and more than 20 of making false statements.

They’re accused of submitting government forms falsely claiming they had sold large amounts of demilitarized M6 to various buyers. The wire fraud charges accuse them of emailing those forms to the U.S. Department of Defense’s Joint Munitions Command. Explo’s contract required it to sell or otherwise dispose of M6 within a year of getting it out of the artillery rounds, the indictment said.

Aside from conspiracy, the only charge against Charles Ferris Callihan of Shreveport, the director of engineering and environmental control, is a false statement charge alleging that he lied when he told the Occupational Safety and Health Administration the M6 was stored only in magazines.

Koons also is accused of lying to the Joint Munitions Command by emailing a request to stop sending propellant to Camp Minden because of an annual audit by state police and the Bureau of Alcohol, Tobacco and Firearms. The real reason, according to the indictment, was that state police were searching the premises and had ordered Explo to stop accepting propellant because it was out of storage space.

Attorneys who represented Smith and Koons in a related state court case did not immediately respond Thursday to calls and emails from The Associated Press. It was not immediately clear who represents Lampkin and Callihan.

State court proceedings have been on hold since November, Hathaway said in an email.

Louisiana 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 160 tons of clean-burning igniter and the M6, much of it in bags in the open. Explo Systems went bankrupt in 2013.

After years of debating how to get rid of the M6 and other materials, the National Guard hired Explosive Service International of Baton Rouge for $32 million to design a chamber to capture any pollution and to burn the materials. Louisiana has paid the Environmental Protection Agency over $1 million to oversee the cleanup.

The EPA approved the system in mid-June.

Just under 5 million pounds of the M6 propellant, or 31.2 percent of the total, has been burned, according to statistics on the internet. Those are automatically updated every 15 to 30 minutes, company vice president Jason Poe said Thursday.

“We’re getting rid of 100 percent of the material,” he said. Poe said the EPA-mandated tests found that treatment of gases left from the burning leaves the treated air “cleaner than the air you are breathing right now.”