A change of plea hearing is scheduled Monday for a third defendant in a case involving an industrial explosion at a site leased from the Louisiana National Guard.

Kenneth Lampkin was program manager at Explo Systems, which abandoned 7,800 tons (7,100 metric tons) of potentially explosive artillery propellant at Camp Minden when it went bankrupt in 2013. He has pleaded not guilty to 29 counts of conspiracy, false statements and wire fraud.

His change of plea would leave an owner from Tennessee and two officials to go on trial June 4.

An owner from Kentucky and the company's inventory control officer have pleaded guilty to reduced charges.

Louisiana State Police began investigating Explo Systems in 2012, after an explosion shattered windows miles away, derailed 11 rail cars and created a mushroom cloud.