The Labor Department''s Mine Safety and Health Administration (MSHA) notified all users of the Draeger OXY-K-Plus self-contained self-rescuer (SCSR) that a number of units have been found with chemical contamination in the breathing circuit that could make the devices unusable in an emergency.
MSHA is requiring all underground mines relying on the Draeger units to identify the defective units and immediately remove them from service.
"We have found problems with several units of this model that made them effectively useless and dangerous to use, and we are taking action to protect miners," said Davitt McAteer, MSHA administrators. "We have consulted with the manufacturer and have determined how to identify the defective units. This information is being shared with all mining operations using the Draeger units so that the devices may be immediately replaced with properly working SCSRs."
Based on examinations and discussions with the manufacturer, it has been determined that defective units may be identified by shaking the device and listening for any noise coming from inside the unit.
Draeger units in serviceable condition will not make any noise when the unit is shaken.
In addition, users should follow the "check list" of usage requirements listed in the unit''s manual and remove any unit failing to meet these requirements. Draeger units with missing parts, including the belt plate and claming strap, must be replaced.
Significant contamination by potassium superoxide was found in the breathing circuit of five Draeger units obtained during an audit of the units conducted by the National Institute for Occupational Safety and Health (NIOSH).
Later, additional units obtained from different mines showed the same contamination. The tested devices were manufactured from 1993 to 1997.
The Draeger self-rescuer units are designed to contain potassium superoxide, but significant amounts of the chemical should never be in the breathing circuit.
If a miner tried to use a contaminated unit, it could cause coughing and chemical burns to the mouth an throat.
Approximately 2,400 Draeger OXY-K-Plus units are in use in the U.S. coal industry. MSHA has notified operators of the 45 U.S. coal mines of the problem by telephone.
MSHA said it would continue to investigate the matter with NIOSH.
For more information, go to the agency''s Web site at www.msha.gov.
by Virginia Sutcliffe