It followed a report earlier this month which revealed a high level of failures in the units during random testing.

The US Mine Safety and Health Administration said all units produced by Pennsylvania-based CSE must be replaced with any other approved one-hour SCSRs.

The deadline for replacements on miner-carried units and mantrip storage is April 26, 2013 and every SR-100 must be removed from every mine no later than December 31, 2013.

The announcement was made in conjunction with the US Occupational Safety and Health Administration as well as the National Institute for Occupational Safety and Health.

NIOSH was the overseer of a joint investigation that determined the units did not conform to safety requirements and reported its findings to MSHA on April 13.

“Due to the large number of CSE SR-100s in underground coal mines, multiple SCSRs available to miners, the low probability of failure and the shortage of immediately available replacements, MSHA and NIOSH have determined that an orderly phase-out will better protect the safety of miners than immediate withdrawal of the devices,” MSHA Assistant Secretary of Labor Joseph Main said.

After pulling 500 units at random from across US coal mining operations, NIOSH assessed the group to determine if the units could be accepted as meeting the limiting quality rate of 1.25% for start-up oxygen performance – or no more than three failures from the entire lot.

“NIOSH observed five start-up oxygen failures in the 500 units it tested,” the agency said in its report.

“The maximum number of failures allowed under the limiting quality rate of 1.25 per cent was exceeded, therefore, the 1 per cent maximum allowable failure rate under the protocol was not met.”

MSHA and NIOSH jointly approve respirators for use in the nation’s mines.

At the time of the investigation, the SR-100 was one of just three one-hour SCSR models in use in the industry.

Under the Mine Improvement and New Emergency Response Act of 2006, or MINER Act, all US mines were ordered to provide additional SCSRs for every miner working underground in working sections, on mantrips, in escapeways and outby workways and travelways.

The rule also required SCSRs to be readily accessible in case of an emergency.

Almost immediately after the announcement was made late on Thursday afternoon, producer CSE responded that it had taken its responsibility to the industry very seriously.

“During this process, we have been upfront, transparent and maintained open lines of communication, not only with MSHA and NIOSH but with our customers as well,” the company said.

“We have dedicated all of our resources to solve any concerns during the course of the inquiry.

“We are fully prepared to meet our customers’ needs for SCSRs within the timeline set by the government.”

Additionally, CSE confirmed it had “complete confidence” in its entire line of rescuers and pledged to support the needs of its customers during the forthcoming transition time as well as in the future.

Officials said the producer had always been dedicated to miner safety and pointed to previously released investigative reports by federal officials confirming some 30 miners’ lives were saved over the past decade by using the SR-100 in critical situations.

“This includes miners from Sago and [Upper Big Branch],” CSE said.

“It is important to note, CSE voluntarily ceased production of the SR-100 when the company’s internal quality control process identified a possible issue with the oxygen cylinder.

“We are in the process of communicating our action plan to each of our customers and we will comply with all required timelines set by the government.”