A crew leadman and a foreman were fatally burned when their oxygen-saturated clothing caught fire. A sanitation district had hired a contractor to install a gate valve in a hydraulic channel. The limited-access channel was pumped out before the work, except for a few inches of sludge. The sewage liquor, previously injected with 60 percent oxygen, was still releasing oxygen into the air. The contractor's leadman was chipping the side of the concrete channel. His pneumatic hammer caused a spark, igniting his clothing. The foreman, who had been working near oxygen vent pipes, jumped into the channel and was also engulfed in […]