Seven years ago, a government engineer in charge of testing emergency air packs used in U.S. coal mines suggested that tests used to approve the devices might not be effective — and that there was no way to know if the air packs were safe.
Nicholas Kyriazi, a biomedical engineer with the National Institute for Occupational Safety and Health, wrote in August 1999 that tests were inadequate for determining how much breathable air the packs would provide a miner in an actual emergency.
But federal regulators didn't act on Kyriazi's suggestions to change the tests. Now, NIOSH officials are re-examining the policy, months after fatal disasters in coal mines in West Virginia and Kentucky raised questions about the safety of the devices.
"We've been looking for a long time at questions of the testing and certification standards," said NIOSH spokesman Fred Blosser, who confirmed the proposal was being reviewed again. "There haven't been any changes since" Kyriazi's report, Blosser said.
CSE Corp. of Monroeville, Pa., manufactures the most commonly used air pack in U.S. coal mines. Officials estimate as many as six in 10 U.S. coal miners carry one underground every day.
The Mine Safety and Health Administration insists that the air packs work properly, and has suggested poor training is to blame for reports that the devices fail when miners need them most.
Tests on devices recovered from West Virginia's Sago Mine, where 12 miners were killed in January, and the Darby No. 1 Mine in Kentucky, where five miners were killed in May, show the air packs were in working order, the agency said.
Yet miners who've used CSE air packs to escape accidents have complained they barely worked and, in some cases, failed altogether.
Roger Perry, a Sago miner who escaped the blast, said breathing with a CSE air pack was like being smothered. Sago survivor Randal McCloy Jr. has said four of the packs assigned to his crew failed after an explosion trapped them underground.
NIOSH certifies air packs by putting the devices on people who perform a series of activities. The amount of oxygen the devices put out and how much carbon dioxide they remove, as well as other data, are monitored during rest periods.
Kyriazi said a more stringent testing regime he recommended in 1999 makes up most of the new certification rules that NIOSH is considering. His report suggested that current testing can't determine how much breathable air the packs would provide in an emergency.
"I have tested the current apparatus and to the new standards," Kyriazi said. "Only one of them would pass."
Blosser said Kyriazi's report is just one piece of information for NIOSH to consider. The re-examination, which is being done in conjunction with MSHA, predates this year's mining disasters, he said.
NIOSH has conducted an ongoing study of air packs with MSHA since 1982. As many as 13 years ago, the study found CSE air packs require users to work harder to breathe than similar devices by rival manufacturers. The studies also show these air packs tend to leave high levels of carbon dioxide in the airstream, making breathing even more difficult.
But Les Boord, director of the NIOSH National Personal Protective Technology Laboratory, says the air packs meet performance standards specified in federal regulation.
CSE product manager Don Pannell says his company's air packs work as designed when users properly inspect them and mine operators properly train workers on using them. However, Pannell said CSE is working on better training equipment that will let miners experience the breathing resistance and heat generated in the air packs before an emergency.
A 2002 report on the MSHA-NIOSH study, the latest available, shows nearly 30 percent of CSE air packs stopped removing carbon dioxide in less than an hour. About 20 percent of CSE air packs forced the user to inhale at least 6 percent carbon dioxide — triple the amount allowed by federal regulation.
Carbon dioxide levels should be 4 percent or lower, the study said, because irregular heartbeat and other problems can occur at higher levels. At somewhere around 10 percent, the user likely would pass out.
Four percent level might be uncomfortable, "but it wouldn't be intolerable," said Robert Banzett, an associate professor at the Harvard School of Public Health. Problems occur, however, when carbon dioxide rises while air flow is restricted.
"If they can't breathe more, it's going to make them feel horribly in need of air."