Michigan Attorney General Dana Nessel has charged four people in connection with the death of a 5-year-old boy who was killed in a hyperbaric chamber explosion in Troy, Michigan.The four were arrested Monday morning and arraigned Tuesday afternoon.

Thomas Cooper from Royal Oak, Michigan, was pronounced dead at the scene. His mother was standing next to the chamber and suffered injuries to her arms when it exploded Jan. 31 at the Oxford Center in Troy.

Four Michigan medical center workers have been charged in the death of a 5-year-old who was burned alive inside a pressurized oxygen tank that exploded.