A scathing report by an independent panel has blamed federal regulators for failing to take steps that might have prevented the disaster that killed 29 workers at Massey Energy’s Upper Big Branch mine two years ago.

The 26-page report by the National Institute for Occupational Safety and Health says that the Mine Safety and Health Administration failed to heed warning signs or implement the agency’s own regulations, leaving in place conditions that led to the explosion and fire that swept through the mine on April 5, 2010.

“If MSHA had engaged in timely enforcement of the Mine Act and applicable standards and regulations, it would have lessened the chances of — and possibly could have prevented — the UBB explosion,” says the report, which was first posted online by Charleston Gazette reporter Ken Ward. The Labor Department released the report Friday evening.

The report — which was requested by Labor Secretary Hilda L. Solis — puts the focus on MSHA’s leadership, which only recently issued its own internal review blaming Massey Energy and mistakes by low-level inspectors. But MSHA did not place responsibility on senior officials in the agency, which is led by a former mine workers’ union leader, Assistant Secretary of Labor Joe Main.

The new report says that while it agreed Massey had caused the explosion, the MSHA review’s “characterization of the facts underlying this conclusion understates the role that MSHA’s enforcement could have had in preventing the explosion.”

Main defended the agency in a statement Friday evening. “Under the Mine Act, Congress gave mine operators responsibility for running safe mines,” he said. “Four investigations into the explosion all show that Massey Energy did not live up to that charge. Recent testimony confirmed that mine management routinely used illegal tactics to conceal violations from inspectors. MSHA cannot keep miners safe alone – mine operators must commit themselves to safety and health.”

Main said that MSHA has already made “improvements” to keep miners safe and said it would review the new report.

The NIOSH report, however, said that the agency didn’t need new regulations; it needed to enforce existing ones. The report singled out regulatory steps that should have been taken to reduce explosive methane and dust levels — or close down the mine entirely.

The report said “the mine operator did not, and could not, conceal readily observable violative conditions such as float dust accumulations throughout the UBB and missing supplemental roof supports.”

It added that if MSHA inspectors had “completed required enforcement action during at least one of the four UBB inspections” then it would have been “unlikely” that air flow in the mine would have been reduced or that a gas explosion would have taken place. Inspectors failed to order supports that would have prevented a roof fall that restricted air flow.

The new report also said that “if MSHA enforcement personnel had taken appropriate actions during the inspections in the months prior to the explosion, either dangerous accumulations of explosive coal dust would have been rendered inert, or the mine would have been idled.” The high levels of coal dust allowed the methane gas explosion to ignite a bigger dust explosion, the report said.

“Even when MSHA enforcement inspectors observed excessive accumulations of explosive coal dust, they failed to take appropriate enforcement actions,” the report said.

Solis did not comment on the report, but it is likely to give new fodder to many mine safety experts who had been critical of the MSHA’s top officials and its Upper Big Branch internal review even before the new report.

In a recent interview, Davitt McAteer, who had been MSHA’s head under President Clinton and who wrote a report on the Upper Big Branch accident for the West Virginia state government, said that “you have inspectors at both state and federal level walking by violations in the mine for whatever reason, whether from intimidation or laziness or whatever, it doesn’t matter.”

He said “you’ve got to adopt a strategy to change the way people think about enforcement.”

Another former inspector said in an interview that Main and other top MSHA division chiefs got weekly reports about mines with multiple serious violations and that Upper Big Branch had to be at or near the top of that list almost every week yet they failed to take tougher action against the Massey mine.

The new report was written by four experts appointed by NIOSH director John Howard and chaired by Lewis V. Wade, a structural and mining engineer at Carnegie Mellon University.

It also pointed to a variety of other problems with the mine safety agency, such as an “antiquated system for tracking methane liberation” and computer errors for tracking patterns of safety violations.

The report said “the agency has had persistent and substantial difficulty in parlaying the insights contained in its internal review reports into a process of continuous quality improvement.”

As a result, it recommended the creation of an independent monitor who would oversee the “implementation of . . . corrective actions” and would have the power to carry out period audits of the agency’s work.