A man has been sentenced to more than a year in prison in connection with the death of a 5-year-old boy who was killed in a fiery explosion inside a hyperbaric oxygen chamber last year.
Jeffrey Mosteller, 66, pleaded no contest to involuntary manslaughter in Oakland County circuit court in Michigan on Monday.
Mosteller will serve 19 months in prison, avoiding the maximum penalty of 15 years behind bars. He was the safety manager at the Oxford Center, an alternative healthcare center that treats children with various health conditions — including autism, ADHD and autoimmune diseases — through hyperbaric oxygen therapy.
Thomas Cooper, of Detroit suburb Royal Oak, died while undergoing treatment at the center in January 2025 after the hyperbaric chamber caught fire from the inside and exploded.
His family’s attorney, James Harrington, previously told NBC News that the boy was going to the Oxford Center to treat sleep apnea and attention-deficit/hyperactivity disorder.
Harrington also told NBC News that the boy’s mother rushed toward the chamber when the fire ignited, burning her arm in an unsuccessful attempt to save her son. The boy was burned alive in front of her, the lawyer said,
Prosecutors have accused the center of “deliberately disregarding” safety protocols set by the National Fire Protection Association (NFPA) and Sechrist Industries, the manufacturer of the hyperbaric chamber.
Mosteller was one of four former Oxford Center employees criminally charged in connection with the boy’s death.
Tamela Peterson, the clinic’s owner, and Gary Marken, the facility’s primary management assistant, each face a single charge of second-degree murder or involuntary manslaughter. Aleta Moffitt, the operator of the hyperbaric chamber, was charged with one count of falsifying medical records for allegedly entering false information on a patient chart.
The three other former employees have pleaded not guilty and are awaiting trial.
Mosteller could face additional prison time and be denied parole after 19 months if he behaves poorly behind bars.
“I expect his conduct will be stellar and I hope that he will be released at the 19-month mark,” his attorney, Alona Sharon, said in a statement.
The Michigan Attorney General’s Office did not immediately return a request for comment.
In July, Michigan Attorney General Dana Nessel announced that a plea agreement had been reached with Mosteller.
“A young child lost his life in a completely preventable tragedy because this defendant allowed an outdated device to operate in defiance of safety standards,” Nessel said in a statement at the time. “While no outcome can reverse this loss, it is my hope that this conviction provides a sense of justice to Thomas’s family.”
Cooper’s parents have filed a civil lawsuit against the Oxford Center and Sechrist, seeking $100 million in damages over the boy’s death.
