One man is dead after fire inside a hyperbaric chamber in Lake Havasu City, Ariz., the second such fatality in the United States this year.

A hyperbaric chamber caught fire in Arizona, leading to the gruesome death of a 43-year-old man inside the highly pressurized, oxygen-filled compartment, authorities said Thursday.

Emergency personnel found the 43-year-old physical therapist dead inside the chamber at his Arizona health clinic, which offered oxygen therapy.