The family of Lawrence Bass, the worker who died in an explosion at the Lake City Army Ammunition Plant two years ago, has filed a $20 million wrongful death suit against the United States through the Department of Defense, alleging that negligence and lapses in oversight contributed to the fatal blast.

Bass, 55, died when a batch of tetrazene, an explosive compound used in detonators, ignited during the manufacturing process while he was directly next to the material. Four other workers were injured in the April 11, 2017 blast.

The suit, filed this month in federal court in Kansas City, alleges that the Army did not – as it should have – identify differences between the plant's Standard Operating Procedure and what workers actually did at times.

Lake City, owned by the federal government, is the largest small-caliber ammunition producer for the U.S. armed forces, and at the time of the explosion was operated by private contractor Orbital ATK. Northrop Grumman, which purchased Orbital ATK in 2018, has bid to retain the operating contract. The Army is expected to announce that decision later this year.

According to the lawsuit, the Army is responsible for auditing compliance but did not maintain appropriate oversight record or conduct required safety reviews.

Investigators from the Bureau of Alcohol, Tobacco, Firearms and Explosives could not determine a certain cause for the explosion – saying it could have been an electrostatic discharge or the friction, impact or stab as Bass used an anti-static plastic spatula to manipulate the material – it ruled out intention action by Bass.

Video surveillance, the ATF said in its report, according to the suit, “did not reveal any abnormal behavior or movements by Bass as we he worked.”

According to the suit, the spatula was not in Orbital's Standard Operating Procedure and the ATF noted that the “wedging” method Bass and others used, while a common practice at the plant, is also not noted in the SOP. Bass' supervisors reviewed video footage of the incident and said they did not see “any safety violations of deviations from the Standard Operating Procedures.”

At that particular stage in manufacturing, tetrazene has a consistency “like cake batter or silly putty,” and if too wet it can't be used in ammunition. But if too dry it becomes more susceptible to explosion.

The lawsuit also mentions the financial issues faced by Orbital ATK as a possible factor. Alliant had acknowledged an “aggressive bid” to win renewal of the Lake City contract in 2013 and said it would have to reduce costs to make a profit. Orbital merged with Alliant in 2015 to create Orbital ATK.

Early this year, Orbital ATK agreed to a $108 million settlement with investors who had filed a class-action lawsuit alleging false statements about profits. The initial complaint had been filed in 2016

Given those financial issues, the suit says, the Army and Department “knew … or should have known” that Orbital ATK was negligent, under extreme cost pressure and motivated to cut costs at the expense of safety.