Nik Rajkovic / news@whmi.com

One of four people charged in the deadly hyperbaric chamber explosion at the Oxford Center in Troy has pleaded no contest to a lesser charge.

Safety Director Jeffrey Mosteller pleaded no contest Tuesday to involuntary manslaughter, dismissing an additional charge of second-degree murder, according to the Michigan Attorney General's Office. He faces up to 15 years in prison when sentenced in Oakland County August 31.

“A young child lost his life in a completely preventable tragedy because this defendant allowed an outdated device to operate in defiance of safety standards,” said Attorney General Nessel. “While no outcome can reverse this loss, it is my hope that this conviction provides a sense of justice to Thomas’s family.”

Three other defendants — Oxford Center CEO Tamela Peterson, operations manager Gary Marken and chamber operator Aleta Moffitt — are still awaiting trial.

All of them charged after a 5-year-old boy was killed while undergoing treatment inside a hyperbaric chamber which caught fire in January 2025.

A former employee has testified Oxford Center workers ignored safety protocols by not using grounding straps during hyperbaric treatment.