Abstract: At 1:15 p.m. on September 17, 2019, an employee was filling a portable oxygen cylinder for air transportation service support. The employee and his coworker were using a portable compressed gas system that included an oxygen driven reciprocating compressor and a Futurecraft oxygen intensifier, Part #90970-2. The oxygen intensifier stopped filling and moments later an oxygen explosion occurred that enveloped the employee and knocked him approximately 15 feet backwards from where he was standing. The employee suffered burns to the left hand and arms, lacerations and puncture wounds from shrapnel, and head and brain injuries from the force of the blast, the fire and the flying debris. The employee was hospitalized.