"It appears the problem cannot be isolated to newer manufacturing," Boord said. "The issue can apply to all CSE units."
The SR-100 model uses a chemical process to generate the oxygen needed for a 60-minute supply of breathable air. Generally, the SR-100 units are started by pulling a large orange tab that activates an oxygen cylinder. The cylinder inflates a breathing bag. Once a miner starts breathing through the bag, the exhaled gases react with the unit's chemicals to generate more oxygen for the miner.
SR-100s can also be started manually if the oxygen cylinder fails to inflate the breathing bag. But that process involves breathing ambient air -- which could be full of smoke -- and exhaling into the mouthpiece to start the chemical reaction.
Over the years, coal miners have complained repeatedly about SCSRs not starting or appearing to start slowly. Government and industry officials have generally dismissed those complaints. They said miners were not properly trained and did not understand how their SCSRs worked.
Months after the Sago disaster, survivor Randal McCloy said the SR-100s of four of the 12 miners trapped by the Jan. 2, 2006, explosion would not start. McCloy described how he tried especially hard to start the rescuer that belonged to his mining partner, Jerry Groves, who eventually died of carbon monoxide poisoning.
"I fought with it for I don't know how long, trying to mess with that valve, blow air through it, or anything I could do, but nothing would work," McCloy told investigators.
In lawsuits filed after the disaster, Sago miners' families were investigating concerns that the SR-100 oxygen cylinders -- made by South African-based African Oxygen Ltd. -- somehow leaked, leaving them without enough oxygen to properly start the units. Most of the suits against CSE have been settled, court records show.
CSE said in February that company representatives planned to visit mines with affected units "to replace the units and provide additional training and outreach."
But Shearer said the company has focused only on encouraging mine operators to remind workers of how to perform the manual start. Shearer said NIOSH would not currently allow his company to replace any problem SR-100s with new units.
Boord said the decision not to ship new units is actually a voluntary one by CSE. Boord said there is nothing preventing CSE from taking units that might be affected by the problem out of the mines -- but that mine operators would then have to replace them with units from one of CSE's competitors. So far, neither NIOSH nor MSHA has made any move to require such action.
"That would be a potential remedy," Boord said. "But until the problem is identified and a corrective action is identified, we can't really say what should happen."
Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.