TROY, Mich. (WXYZ) — A judge heard testimony on Monday in connection with an explosion at a medical facility that claimed the life of a little boy.
The explosion happened on Jan. 31 at The Oxford Center in Troy.
Watch Darren Cunningham's video report below:
Five-year-old Thomas Cooper was receiving treatment in a hyperbaric chamber when it exploded, killing him.
Michigan Attorney General Dana Nessel announced the charges in March.
“This tragedy could have been prevented if proper safety protocols were followed,” Nessel said in a previous statement. “Instead, deliberate negligence and a blatant disregard for safety cost a child his life. I appreciate the investigatory efforts of the Troy Police Department. My office remains committed to seeking justice for Thomas and holding those responsible accountable.”
VIDEO: WATCH THE AG'S FULL PRESS CONFERENCE
A judge heard testimony Monday to see if there is enough evidence to send the owner and three employees at the facility to trial.
The first and only witness to testify on day one of the preliminary hearing was a former employee who says taking a critical shortcut was the norm.
"My primary concern is that we were not putting grounding straps on the patients,” former employee Tiffany Hosey said.
Visibly anxious, Hosey testified that she warned former co-workers about what she felt was a safety risk months before the death of Thomas.
CEO Tamela Peterson, who's charged with second-degree murder, watched the first day of the hearing in court.
The judge asked Hosey what Peterson said about not using grounding straps.
“She saw them as a strangulation risk for some of the kiddos," Hosey said.
Jeff Mosteller and Gary Marken are also charged with second-degree murder. The prosecutor charged Aleta Moffitt, the operator of the hyperbaric chamber, with involuntary manslaughter and intentionally placing false information on a medical record.
Watch the arraignments in the video below:
Hosey says she raised concerns several times to Peterson and Mosteller that failing to use grounding straps, which go around the patients’ wrist while inside a chamber, was a fire hazard.
“I was told that I was uneducated and ill-informed,” Hosey said.
A defense attorney asked Hosey “who told you that?”
“Tammy told me that," Hosey responded. "About a week later, I was let go."
But the defense attorneys objected, saying Hosey worked at the Brighton location and not in Troy where the incident happened. They also said she left in April of 2024.
The defense suggested her testimony about the Troy location was speculative.
One attorney also questioned her efforts to report the facility.
“You were employed at the center for roughly 45 months, during which you allegedly had all these safety concerns. Did you report it to any outside agency?"
“Officially report? No,” Hosey said.
“So, you only took your concerns in house. Is that fair?” the defense asked.
“That's true," Hosey responded.
The Oxford Center released the following statement about the charges:
After cooperating with multiple investigations starting immediately after the tragic accident in January, we are disappointed to see charges filed.
The timing of these charges is surprising, as the typical protocol after a fire-related accident has not yet been completed. There are still outstanding questions about how this occurred. Yet, the Attorney General’s office proceeded to pursue charges without those answers.
Our highest priority every day is the safety and wellbeing of the children and families we serve, which continues during this process.
Thomas’ family is being represented by Fieger Law.
James Harrington, managing partner at Fieger Law, told us in February that Thomas had received 35 treatments and the explosion happened during his 36th treatment.
Previous coverage: Attorney for family of 5-year-old boy killed in hyperbaric chamber speaks out
"Under no circumstances should anything like this ever happen — ever," Harrington previously told us. "When we met with the family, it was one of the most heartbreaking things I’ve ever seen."
Thomas’ mother was also reportedly in the room and sustained some injuries to her arms.
Previous coverage: 5-year-old boy killed in hyperbaric chamber explosion loved running, swimming; GoFundMe set up for family
Officials say the chamber contains 100% oxygen, which is five times the amount of oxygen in a normal room, and can be “extremely combustible.”
According to The Oxford Center website, the therapy is a "specialized form of medical treatment administered by delivering 100% pure oxygen to the body through increased atmospheric pressure greater than 1.3 ATA in an enclosed hard chamber."
According to a GoFundMe page, Thomas loved life, running, and swimming, and he liked to draw and figure out how things worked. Thomas leaves behind his mom, dad, and younger brother.
The hearing resumes Tuesday morning.
