Jessica Mathews / news@whmi.com

Preliminary exams got underway Monday in a Troy courtroom for four people charged in the death of a 5-year-old boy who died in a hyperbaric chamber explosion.

Thomas Cooper from Royal Oak was “incinerated” when the pressurized oxygen chamber exploded in January at the Oxford Center in Troy.

Owner 58-year-old Tami Peterson of Brighton; Safety Manager 64-year-old Jeffrey Mosteller of Clinton Township; and 65-year-old Gary Marken of Spring Arbor, the primary management assistant at the facility, each face one count of 2nd degree murder - a potential life offense - or alternatively, one count of involuntary manslaughter, a 15-year felony.

60-year-old Aleta Moffitt of Rochester Hills, the operator of the hyperbaric chamber, is charged with one count of involuntary manslaughter and one count of medical records – intentionally placing false information on a chart, a four-year felony.

The Detroit News reports that Former Research Assistant and Hyperbaric Chamber Technician Tiffany Hosey testified Monday that she raised safety concerns to Peterson and Mostellar about not putting grounding straps on patients but nothing was done and she was later let go.

Hosey was the first witness called. The News reports defense attorneys reportedly raised a number of objections to her testimony as she never worked at the Troy location. However, Hosey said she had done work there before and believed safety protocols were the same. She later stated that, despite safety concerns; she continued with the policy of not using grounding straps.

Michigan Attorney General Dana Nessel announced charges in March, stating “The Oxford Center routinely operated sensitive and lethally dangerous hyperbaric chambers beyond their expected service lifetime and in complete disregard of vital safety measures and practices considered essential by medical and technical professionals. This tragedy could have been prevented if proper safety protocols were followed. Instead, deliberate negligence and a blatant disregard for safety cost a child his life”.

The Oxford Center had locations in Troy and Green Oak Township and provided therapy for children with various health conditions including autism, ADHD, and auto-immune diseases, through Hyperbaric Oxygen Therapy.

On January 31st, while Cooper was undergoing treatment, the hyperbaric chamber caught fire from the inside and exploded. Cooper’s mother suffered burn wounds as she tried to save her son. The family is being represented by the Feiger Law Firm.

The Oxford Center said shortly after the explosion in a statement that “the safety and wellbeing of the children we serve is our highest priority. Nothing like this has happened in our more than 15 years of providing this type of therapy. We do not know why or how this happened and will participate in all of the investigations that now need to take place”.

Raymond Cassar, Marken’s attorney, earlier said the second-degree murder charge comes as “a total shock” and it was “a tragic accident”.

Moffitt’s lawyer, Ellen Michaels, earlier told the AP “Aleta Moffitt is a dedicated professional with many years of experience in the healthcare industry. She has always been a committed and hardworking individual, adhering to all corporate policies and procedures while prioritizing the well-being of her patients.”