One of four people charged in the deadly hyperbaric chamber explosion that left a 5-year-old boy dead has pleaded no contest.
Jeffrey Mosteller, the safety director at the Oxford Center in Troy, pleaded no contest to involuntary manslaughter Tuesday in Oakland County Circuit Court. An additional charge of second-degree murder was dismissed. Mosteller faces up to 15 years in prison for involuntary manslaughter.
Thomas Cooper, 5, died in an explosion in January 2025 inside a hyperbaric oxygen chamber. He had been undergoing treatment at the Oxford Center’s Troy location for ADHD and sleep apnea. During a treatment on Jan. 31, 2025, a fire sparked in the chamber, killing him.
Mosteller’s attorney, Alona Sharon, declined to comment Tuesday.
Three other defendants — Oxford Center CEO Tamela Peterson, operations manager Gary Marken and chamber operator Aleta Moffitt — are still awaiting trial. Peterson has a motion hearing Wednesday and Marken and Moffitt have a pretrial July 27.
Peterson and Marken are charged with both involuntary manslaughter and second-degree murder. Moffitt is charged with involuntary manslaughter and entering a false medical record.
During the last day of the preliminary examination in February, Judge Maureen McGinnis of Troy’s 52-4 District Court cited the importance of former employees’ testimony that their concerns about safety and grounding straps were brushed aside by Peterson, Marken and Mosteller.
Former employee Tiffany Hosey, who was fired after she said she brought up safety concerns to Peterson and Mosteller, testified that the Oxford Center did not use grounding straps as patients were receiving treatment in hyperbaric chambers.
Hosey said Peterson told her they did not use grounding straps because she saw it as a strangulation risk for the children they treat and because Mosteller had done some independent testing to show why they didn’t need grounding straps.
Prosecutors also alleged that Peterson, Mosteller and Marken ignored guidance from the chamber manufacturer’s manual, the National Fire Protection Association and the Oxford Center’s own training materials about safety in hyperbaric chambers.
Mosteller will be sentenced Aug. 31.
kberg@detroitnews.com
This article originally appeared on The Detroit News: 1 of 4 charged in Troy hyperbaric chamber death pleads no contest
Reporting by Kara Berg, The Detroit News / The Detroit News
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By Kara Berg, The Detroit News | USA TODAY Network
