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 flames. Co-workers saw the two running through the channel and yelled at them to roll on the ground. A third worker leaned over the channel and his shirt caught fire.

Firefighters later found two nearly-naked men. Their visible skin areas were sloughed from second- and third-degree burns on more than 80 percent of their bodies. The third victim had milder burns. The first two died from heart and breathing failure.

When oxygen-enriched clothing contacts a spark, fire is severe, hot and fast. Supervisors should know the hazards of any confined space and inform contractors. There should be a written program for confined space testing, entry procedures and rescue plan.