A preliminary hearing in the fatal hyperbaric chamber explosion in Metro Detroit was wrapping up on Tuesday for the four people charged in the death of a five-year-old boy.

Former Oxford Center CEO Tamala Peterson, Gary Marken, Aleta Moffitt and Jeffrey Mostellar are accused of not following safety protocols while working there, leading to the death of Thomas Cooper.

A judge will now decide whether this case will go to trial.

The prosecution is asking that all charges for all four defendants be bound over to trial, arguing that they intentionally ignored safety steps that could have prevented the child's death.  

"What we've learned about what's really going on is that the Oxford Center does not operate safely, and they disregard safety precautions. Did the defendants knowingly and obviously disregard life-endangering consequences?" said Assistant Attorney General Chris Kessel.

Kessel cited testimony that claimed the center failed to follow numerous safety protocols and that they knew those steps would decrease the risk of a deadly fire.   

The defense explained that their clients honestly felt their operations were safe, claiming that they otherwise wouldn't have used those chambers for their own treatment.

"She would not have put her own family members in jeopardy, other members of the Oxford Center, herself in jeopardy if she had the knowledge for second-degree murder," said Peterson's attorney, Tom Cranmer.

"They wanted to fit a square peg into a round hole, and the evidence came out that that wouldn't work," said Marken's attorney, Todd Flood.

Former employees and hyperbaric chamber experts testified throughout the past couple of months that the facility failed to use grounding straps as early as 2017, something one former employee testified to not always being the case. They also testified that a polyester pillow was used in the chamber, something that another witness who works for the company that makes the chambers says should never be used.

Another employee testified that Thomas was given a blanket fresh out of the dryer before his treatment, which investigators and hyperbaric chamber experts testified to increasing the risk of a static spark that could ignite the chamber.

On Tuesday, Michigan Attorney General Dana Nessel announced health care fraud charges against Peterson. Each charge carries up to four years in prison and/or a $50,000 fine.