OAKLAND COUNTY, Mich. – The CEO and three other workers of an Oakland County facility are facing charges after a 5-year-old boy died in a hyperbaric chamber.
Here’s a timeline that details everything we’ve learned from the day of the explosion to the arrest and arraignment of the employees.
Child killed in hyperbaric chamber
Thomas Cooper was killed on Jan. 31, 2025, when the hyperbaric chamber he was in at the Oxford Center in Troy exploded.
First responders were called to the facility shortly before 8 a.m. that day.
They said that Cooper was dead when they arrived at the scene.
Mom injured
The boy’s mother sustained injuries to her arms when she tried to get Cooper out of the chamber.
Crews put out fire
The fire was put out within minutes. There was no extensive damage to the center, according to the fire department.
Family of boy killed retains attorney
On Saturday, Feb. 1, we learned that Fieger Law was retained to represent the family of the 5-year-old boy and the child’s mother.
“This is an unimaginable tragedy, and our hearts are with the family as they navigate this immeasurable loss,” said James Harrington, Managing Partner of Fieger Law. “We ask that the public and media respect the family’s privacy at this time. We are investigating every aspect of this matter and will report our findings in due time. The safety of children should always be the top priority, and this incident raises serious concerns about hyperbaric chambers and the oversight and regulation of hyperbaric treatments.”
Read more -- Family demands answers after 5-year-old boy dies in hyperbaric chamber explosion at Troy facility
Harrington said the lawsuit hasn’t been filed yet due to the ongoing investigation, but they filed a motion for injunctive relief so the firm’s team can enter the building where the explosion happened and conduct their own inspection with their experts.
CEO, 3 other workers arrested and charged
Michigan Attorney General Dana Nessel held a press conference on Tuesday, March 11, to announce arrests and charges in the case.
Four Oxford Center employees were arrested on Monday, March 10.
Second-degree murder charges were filed against the following employees:
- Oxford Center Founder and CEO Tamela Peterson, 58, of Brighton
- Oxford Center Safety Manager Jeffrey Mosteller, 64, of Clinton Township
- Oxford Center Primary Management Assistant Gary Marken, 65, of Spring Arbor
A fourth employee, Aleta Moffitt, 60, of Rochester Hills, who officials say was operating the hyperbaric chamber at the time of the explosion, was charged with involuntary manslaughter and falsifying medical records.
“This tragedy could have been prevented if proper safety protocols were followed,” Nessel said. “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.”
4 workers arraigned on charges
Peterson, Mosteller, Marken and Moffitt were arraigned in the afternoon on Tuesday, March 11, before Magistrate Elizabeth Chiappelli.
The CEO was given a $2 million bond, while Mosteller and Marken received $250,000 bonds.
Bond was set at $100,000 for Moffitt.
Local 4 learned that Marken and Moffitt have been released on bond.
During the arraignments, Assistant Attorney General Chris Kessel argued that Peterson was a flight risk because she had access to a “considerable amount of cash” and because her husband is a forensic accountant.
He mentioned that she had a Visa to China, but her attorney said she got it in August 2024 because her son got married in China.
Workers created ‘ticking time bombs’
Chiappelli also discussed how investigators learned that the workers were allegedly tampering with the hyperbaric chambers and rolling back the cycles.
“They further advised that they had written documentation between themselves and Peterson advising her that the cycle count on the chamber that had exploded was over 20,000 cycles when they were at the facility in 2022,” Troy Detective Danielle Trigger said in the swear-to. “I reviewed photos of the chamber cycle counter from the date of the incident that were taken on scene, which showed that the chamber cycle count on that date was 19,894, which would be consistent with the rollbacks reported by ex-employees.”
Marken was accused of setting back the cycles of the machines, and Mosteller was accused of performing “experiments” to show other employees that the chamber was still safe despite what they were doing to alter it.
During the arraignments, the prosecutors said the workers essentially created “ticking time bombs” with the way they were altering the chambers.
You can watch the full arraignments in the video below:
For more details about what investigators learned, including allegations against the employees, text messages sent by the CEO and other safety protocols that were allegedly disregarded, check out this article.
Next court dates
All four employees are scheduled to appear in court on March 19 for probable cause conferences and March 26 for preliminary examinations.
