Three people have been charged with second-degree murder after a 5-year-old boy was killed when a hyperbaric chamber exploded at a medical facility in Michigan earlier this year, officials announced Tuesday.

Four people have been charged in the death of a 5-year-old boy who was killed inside a pressurized oxygen chamber that exploded at a suburban Detroit medical facility.

Tamela Peterson, owner and founder of the Oxford Center, was given a $2 million bond. Three other employees also charged.