Safety manager gets prison in hyperbaric chamber death

A former safety manager at a Michigan alternative health clinic has been sentenced to 19 months in prison after a 5-year-old boy died in a fire and explosion inside a hyperbaric oxygen chamber during treatment.

Jeffrey Mosteller, 66, pleaded no contest Monday to involuntary manslaughter in Oakland County Circuit Court in connection with the January 2025 death of Thomas Cooper of Royal Oak, Michigan. Mosteller had faced up to 15 years in prison.

Mosteller worked at the Oxford Center, an alternative healthcare facility that treats children with conditions including autism, attention-deficit/hyperactivity disorder and autoimmune diseases through hyperbaric oxygen therapy. Thomas was undergoing treatment at the center in the Detroit suburb of Troy when a fire erupted inside the chamber and triggered an explosion.

The boy’s family attorney, James Harrington, previously told NBC News that Thomas had been taken to the Oxford Center for treatment of sleep apnea and ADHD. Harrington said the child’s mother rushed toward the chamber when the fire began and burned her arm in an unsuccessful attempt to save him. The Guardian reported that she was badly burned on her arms and chest while trying to open the tank.

According to The Guardian, an expert who reviewed video of the incident said Thomas had squirmed enough to pull a sheet off a mattress inside the chamber, causing a spark of static electricity. In the oxygen-rich environment, the spark became a flash fire that incinerated him within seconds, the newspaper reported.

Prosecutors have accused the Oxford Center of “deliberately disregarding” safety protocols set by the National Fire Protection Association and Sechrist Industries, the manufacturer of the hyperbaric chamber.

Mosteller is one of four former Oxford Center employees criminally charged in connection with Thomas’s death. The others have pleaded not guilty and are awaiting trial, NBC News reported.

Tamela Peterson, the clinic’s owner, and Gary Marken, the facility’s primary management assistant, each face charges tied to second-degree murder or involuntary manslaughter, according to NBC News. The Guardian reported that Peterson, 58, the Oxford Center’s founder and chief executive, was charged with second-degree murder, while Marken, 65, the facility manager, was charged with second-degree murder and involuntary manslaughter. Aleta Moffitt, 60, who was operating the chamber when it exploded, was charged with involuntary manslaughter and intentionally placing false medical information on a medical records chart, The Guardian reported. NBC News reported that Moffitt was charged with falsifying medical records for allegedly entering false information on a patient chart.

Mosteller could face additional prison time and be denied parole after 19 months if he behaves poorly while incarcerated. “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.

Michigan Attorney General Dana Nessel announced in July 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 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.”

The Michigan Attorney General’s Office did not immediately return NBC News’ request for comment after the sentencing.

Hyperbaric oxygen therapy delivers pure oxygen to a person inside a pressurized chamber. The Guardian reported that the Food and Drug Administration has cleared hyperbaric chambers to be marketed as safe and effective for 13 disorders, including severe burns, decompression sickness and non-healing wounds.

Thomas’s parents have filed a $100 million wrongful death lawsuit against the Oxford Center and Sechrist over their son’s death.