Nearly six years after the Deepwater Horizon disaster, Robert Kaluza is set to have his day in court.

Kaluza, a former BP supervisor who was assigned to the drilling rig just days before it exploded on April 20, 2010, is the last of five workers who faced criminal charges in connection with the accident, which killed 11 men and spilled millions of barrels of oil into the Gulf of Mexico.

The government said that in the hours before the blowout, Kaluza misinterpreted a critical safety test and ignored warning signs that the well was in danger.

Kaluza and former BP supervisor Donald Vidrine were charged in a 2012 federal indictment with 11 counts apiece of seaman’s manslaughter and involuntary manslaughter, as well as a lone count of violating the federal Clean Water Act.

But the government’s case has mostly cratered, and on Tuesday, Kaluza is slated to stand trial on the single pollution charge, a misdemeanor.

The once-daunting indictment started to fall apart in 2013, when U.S. District Judge Stanwood Duval Jr. dismissed the charges of seaman’s manslaughter against both Kaluza and Vidrine. He ruled that the law is aimed at a captain or someone in charge of operating a vessel, not supervisors on a drilling rig.

Then, in a surprise move late last year, prosecutors asked Duval to dismiss the remaining 11 involuntary manslaughter charges against both men “in the interests of justice,” leaving them both to face the single pollution charge.

That same day, Vidrine pleaded guilty to that count, accepting a plea deal that lets him avoid jail time in exchange for probation, community service and $50,000 in restitution. Duval has set a sentencing hearing for him for April.

But Kaluza turned down a similar deal, instead choosing to fight the misdemeanor count at a trial that may last two weeks or more. The charge carries a maximum penalty of a year in prison, plus a fine.

Like the other three former BP workers charged in the spill’s aftermath, the grand jury charged Kaluza with much more serious crimes than what he is now facing. The pattern has led some legal experts who have followed the litigation to judge the federal government’s entire effort to hold individuals criminally liable for the disaster to be mostly a failure.

They point out that the government never charged high-level BP executives who helped create the company’s admittedly negligent practices, while prosecutors eventually backed off most of their most serious allegations against lower-ranking employees.

Kaluza refused to testify in hearings after the spill, invoking his Fifth Amendment right against self-incrimination. In court filings, he has maintained his innocence.

Michael Magner, a former federal prosecutor who represented former BP executive David Rainey in a trial last summer that hinged on whether Rainey deliberately hid the spill’s severity from federal investigators, said Kaluza’s decision not to take a deal similar to Vidrine’s carries some risk.

He noted that the benchmark for proving negligence under the Clean Water Act is “ordinary negligence.” In order to make their case, prosecutors will have to prove only that Kaluza failed to act as a reasonably prudent person would have acted when faced with a similar situation.

On the other hand, “The advantage he has is that he’s going to be able to say that he acted in good faith and wouldn’t have put himself at risk of a blowout if he did not believe that he was acting properly,” Magner said. “That’s a big advantage to the defense in the case. I also think, by the Department of Justice dismissing the manslaughter charges, it takes a lot of the danger out of the case for him, so that he doesn’t have a lot to lose by going to trial.”

Kaluza’s attorneys have offered a glimpse into his defense strategy, noting in a recent court filing that they intend to argue that a “combination of circumstances” led to the rig’s explosion and the subsequent oil spill — in other words, that the allegedly botched safety test was not the only reason for the disaster.

After the test was complete, the rig’s crew began removing heavy drilling fluid from the riser — the mile-long pipe connecting the well at the ocean floor to the drilling platform — and replacing it with lighter seawater. That allowed oil and explosive natural gas to flow up the well and onto the rig floor. Before long, the well blew out, igniting the drilling rig and causing it to explode.

Kaluza’s attorneys are expected to maintain that other factors were in play. Had Vidrine or an onshore BP senior engineer stopped the drilling fluid from being removed, perhaps the disaster would have been avoided. Or had the rig’s blowout preventer sealed the well, as it was supposed to do, then the misreading on the safety test wouldn’t have been catastrophic.

“The government is free to argue in closing that Kaluza should have exercised increased care in light of the potential risks, just as Kaluza is free to argue that he exercised an appropriate degree of care under the circumstances,” Kaluza’s attorney, former federal prosecutor Shaun Clarke, wrote in a recent court filing.

Prosecutors likely will argue that the well was doomed once the test was deemed a success, for that led to the decision to remove the mud and replace it with seawater.

In the government’s trial brief, Jennifer Saulino, the head of the Justice Department’s Deepwater Horizon Task Force, said that any subsequent actions taken after the test were “at most failures to prevent the harm put in motion by the defendant’s alleged negligence.”

Clarke declined comment last week, as did a Justice Department spokesman.

In accepting his plea deal last year, Vidrine acknowledged that steps taken by the rig crew after the botched safety test led to “under balancing the well and removing a barrier against the flow of hydrocarbons toward the rig.”

Of the four other men charged with crimes in connection with the spill — Vidrine, Rainey, former BP engineer Kurt Mix and former Halliburton manager Anthony Badalamenti — the government’s efforts have netted three convictions, with each resulting in probation.

The same day Vidrine and Kaluza were indicted in 2012, BP agreed to plead guilty to 11 counts of felony manslaughter, obstruction of Congress and a series of environmental crimes, and to pay a $4 billion fine.

The company later agreed to pay $20 billion more to resolve federal and state claims for economic and environmental damages, plus hundreds of lawsuits filed by local governments.

The trial begins Tuesday in Duval’s courtroom with jury selection.

Follow Richard Thompson on Twitter, @rthompsonMSY.