Oxford safety director pleads no contest in hyperbaric chamber death

Jeffrey Mosteller, the safety director at the Oxford Center in Troy, pleaded no contest July 21 to involuntary manslaughter in the death of 5-year-old Thomas Cooper.

The Michigan Attorney General’s Office announced the plea and sentencing agreement, which calls for 19 months to 15 years in prison. Mosteller is scheduled to be sentenced Aug. 31 by Oakland County Circuit Judge Kwamé L. Rowe. The Associated Press reported that a second-degree murder charge was dismissed as part of the agreement.

Cooper died Jan. 31, 2025, while receiving treatment inside a hyperbaric oxygen chamber at the Oxford Center. His mother, who was near the chamber, was injured. The Attorney General’s Office said the chamber caught fire from inside and exploded.

The office said the National Fire Protection Association and Sechrist, the chamber’s manufacturer, publish safety protocols for hyperbaric treatments. In announcing the plea, the office said Mosteller discarded those protocols and ignored safety precautions.

Attorney General Dana Nessel called Cooper’s death “a completely preventable tragedy” and said she hoped the conviction would provide a sense of justice to his family.

Mosteller is the first of four defendants to resolve his criminal case. Oxford Center owner Tamela Peterson and primary management assistant Gary Marken are awaiting trial on second-degree murder charges or involuntary manslaughter charges. Chamber operator Aleta Moffitt is awaiting trial on involuntary manslaughter and charges of falsifying medical records.

The charges against Peterson, Marken and Moffitt remain allegations. They are presumed innocent unless convicted.

Cooper’s parents filed a civil lawsuit Sept. 22, 2025, in Oakland County Circuit Court. Case No. 2025-217729-NP seeks $100 million from eight defendants, including the four criminal defendants, the Oxford Center and chamber manufacturer Sechrist.

The complaint alleges wrongful death, negligence and product liability. The court has not decided those allegations. Responses to the civil claims and the lawsuit’s current status were not immediately available as of Wednesday, July 22.

Does a no contest plea establish liability in a Michigan civil lawsuit?

No. A no contest plea resolves the criminal charge without serving as an admission of civil liability.

Under Rule 410 of the Michigan Rules of Evidence, a no contest plea generally cannot be admitted against the person who entered it in a civil or criminal case. A limited exception may apply when that person later brings a claim and the plea is used to support a defense.

The rule concerns the plea and certain statements connected to it. It does not automatically exclude other admissible evidence about the underlying events. A civil court must decide the claims under civil standards and the evidence properly presented in that case.

Wrongful death lawsuits in Michigan

Only the personal representative of the deceased person’s estate may bring a wrongful death lawsuit. Under Michigan’s wrongful death statute, the claim may proceed when a death resulted from another party’s wrongful act, neglect or fault and the deceased person could have brought a claim if they had survived.

Family members who may be entitled to damages do not ordinarily file separate wrongful death lawsuits. The probate process appoints the personal representative, who brings the action for the estate and eligible relatives.

Michigan law permits damages that are fair and equitable under the legally established losses. Depending on the circumstances, they may include medical, hospital, funeral and burial expenses, conscious pain and suffering and eligible relatives’ loss of financial support, society and companionship. The court’s distribution process considers the losses suffered by the people entitled to share in the recovery.

Get help from Michigan Legal Center

Michigan Legal Center is the Law Offices of Christopher J. Trainor & Associates. The firm handles Michigan personal injury and wrongful death matters.

People with questions after a death or serious injury can Contact Michigan Legal Center to ask whether the matter is within the firm’s practice.

There is no attorney fee unless money is recovered for you. Case costs and fee terms are governed by the written fee agreement.

Learn more about Michigan personal injury claims.