Abstract: Employee #1 was acting as a standby while Employee #2 and a coworker performed a routine maintenance task on a relief valve and the flare line in the B-reformer unit at the Citgo Refinery in Sulfur, LA. Employee #1 was on a platform located approximately 4 feet lower than the scaffold on which Employee #2 was working. When Employee #2 and the coworker removed a blind, hydrogen sulfide gas was released from the flare line. Employee #1 was overcome by the gas before being able to put on his self-contained breathing apparatus. When Employee #2 jumped down to the platform to rescue Employee #1, his supplied air hose popped loose. The coworker was able to reconnect Employee #2's air hose to the bottled air supply. Employee #1 was pronounced dead on arrival at the local hospital. Employee #2 remained hospitalized for two days for observation.