Faulty Breathing Devices In US Coal Mines

Two years of testing have found a critical defect in a certain model of emergency breathing devices used in U.S. coal mines, but federal regulators have no immediate plans to remove the more than 70,000 air packs that could remain in use. The SR-100 self-contained self-rescuers are belt-worn air packs about the size of three cake-mix boxes. They hold chemicals that help recycle exhaled breath, giving miners about an hour of oxygen and, hypothetically, time to seek refuge or escape from a fire or explosion. The National Institute for Occupational Safety and Health issued a report this week saying five out of 500 randomly sampled SR-100 units had oxygen starters that failed. Under federal rules, no more than three in 500 can fail for NIOSH to remain confident.