An independent review of the federal Mine Safety and Health Administration's (MSHA) enforcement at the Upper Big Branch (UBB) coal mine in West Virginia says the agency failed to spot "a number of enforcement deficiencies" at the mine which were major factors in the April 2010 explosion that took 29 lives.

The report from an independent panel assembled by the National Institute for Occupational Safety and Health contains this stunning conclusion:

"...if MSHA had engaged in timely enforcement of the Mine would have lessened the chances of — and possibly could have prevented — the UBB explosion."

Neither MSHA nor the Labor Department responded to NPR's request for comment. The agencies received the report yesterday and it has yet to be publicly released. Ken Ward of The Charleston Gazette obtained the document and posted it on his Coal Tattoo blog today. NPR obtained the document from one of the NIOSH panelists.

The NIOSH panel's review is the most critical assessment yet of MSHA's enforcement failures at the mine. It is also critical of MSHA's own Internal Review, which was released March 6.

NIOSH investigators did not disagree with MSHA's conclusion that Massey Energy, the owner of the mine at the time, "caused the explosion." But the review panel says MSHA's Internal Review "understates the role that MSHA's enforcement could have had in preventing the explosion."

The NIOSH team absolves MSHA of any ability to prevent the methane ignition that triggered the deadly blast. But it says agency inspectors and supervisors failed to notice and resolve two other serious sets of conditions underground that helped turn a relatively minor methane ignition into a massive explosion.

First, MSHA inspectors failed to complete required enforcement actions during four inspections before the blast. If they had done that for at least one of the four inspections, the report concludes, "it is unlikely that a roof fall would have occurred and that airflow would have been reduced" in the mine.

"With the proper quantity of air, there would not have been an accumulation of methane, thereby eliminating the fuel sources for the gas explosion," the report says.

Second, MSHA inspectors failed to spot and address dangerous accumulations of explosive coal dust. They could have required Massey to render the coal dust inert or they could have idled the mine, according to the NIOSH investigators.

"In short, even if there had been a gas explosion," the report adds, "it would have lacked sufficient fuel to trigger a massive dust explosion."

MSHA's Internal Review and an earlier Accident Investigation Report blamed Massey Energy for concealing serious safety violations from federal inspectors. But the NIOSH team writes, "...the mine operator did not, and could not, conceal readily observable violative conditions..."

The panel also says MSHA's internal review investigators were too narrowly focused when interviewing MSHA staff, leading to a "lost opportunity to pursue a line of questioning to uncover the root cause(s) of a particular enforcement action or inaction."

And in a direct rebuke of the agency's response to five other recent mine disasters, the panel notes "a remarkable overlap in the array of enforcement lapses identified." There was "a very similar constellation of shortcomings" despite five MSHA internal reviews recommending corrective action for the agency.

The five disasters include the methane explosions at the Jim Walter Resources mine in Alabama in 2001, the explosions at the Sago mine in West Virginia and Darby mine in Kentucky in 2006, the fire at Massey's Aracoma mine in West Virginia also in 2006, and two mine collapses in Utah in 2007 at the Crandall Canyon mine.

In all, 70 coal miners perished in those tragedies and the Upper Big Branch explosion.

Update at 6:37 p.m. Statement From MSHA:

The Labor Department has finally made the NIOSH review public and issued a statement from Joe Main, Assistant Secretary of Labor for Mine Safety and Health.

Main does not address any of the MSHA failures outlined in the review. And, remarkably, he repeats MSHA's assertion about Massey Energy deception, even though the NIOSH panel discredits that argument.

"MSHA began making changes in April 2010," Main says, referring to a series of more rigorous inspections and enforcement actions targeting troublesome mines.

"MSHA is committed to rooting out and addressing critical issues within the agency head-on, and agrees more needs to be done to ensure full and effective enforcement of the Mine Act," Main continues. But, as he has in the past, he again shifts total responsibility for the Upper Big Branch disaster to Massey Energy.

"Congress gave mine operators responsibility for running safe mines," Main writes. "Recent testimony confirmed that mine management routinely used illegal tactics to conceal violations from inspectors."

But, as the NIOSH panel clearly notes, "...the mine operator did not, and could not, conceal readily observable violative conditions..."

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