CHARLESTON, W.Va. -- The nation's top mine safety regulator on Tuesday defended his agency in the wake of a government report that said the U.S. Mine Safety and Health Administration likely could have prevented the nation's worst coal-mining disaster in nearly 40 years.

Testifying before a House of Representatives committee, MSHA chief Joe Main disputed the findings of an Upper Big Branch Mine Disaster review by an expert panel of current and former mine safety staff at the National Institute for Occupational Safety and Health.

"Massey caused this disaster," Main told the House Committee on Education and the Workforce. "I haven't seen the facts that tell me that we could have taken the actions necessary to stop that."

Tuesday's hearing marked Main's first appearance before Congress since the release in December of the report on MSHA's investigation into the April 5, 2010, explosion at Upper Big Branch and an "internal review" by MSHA into its own actions prior to the blast.

MSHA investigators blamed the disaster on widespread, repeated and flagrant mine safety violations by Massey Energy, and emphasized Massey's efforts to cover up conditions at the mine by illegally warning underground workers when government inspectors arrived.

But the NIOSH panel, in a report first made public on Friday by the Gazette, concluded that MSHA asked the wrong questions when its internal review concluded nothing MSHA did or didn't do "caused the explosion."

"This characterization of the facts understates the role that MSHA's enforcement could have had in preventing the explosion," the NIOSH panel reported. "Had the MSHA [internal review] considered the causation issue from a broader point of view, the [NIOSH panel] believes that the [internal review team] might also have posed the following question: Would a more effective enforcement effort have prevented the UBB explosion?"

The NIOSH panel reported that MSHA likely could have prevented the disaster had it properly enforced mine ventilation standards and done more to force Massey to clean up explosive coal dust that provided most of the fuel for the blast.

"It is difficult -- almost impossible -- to imagine enforcement personnel missing the inherent dangers of coal dust accumulating throughout the mine," said committee Chairman John Kline, R-Minn. "This enforcement error neglected a crucial safety concern that would later enhance the magnitude of this disaster."

Democratic committee members used Thursday's hearing to again push for passage of a mine-safety reform package, something that Congress has not managed to get done, even as the two-year anniversary of the disaster approaches.

"We recognize that the entire system failed the miners at Upper Big Branch," said Rep. Lynn Woolsey, D-Calif. "Past Congresses shouldn't have slashed funding for mine inspectors. MSHA needed to do a better job with the tools it had. And Massey exploited MSHA's weaknesses and those in the law.

Rep. Nick J. Rahall, D-W.Va., said lawmakers should not use MSHA's failings as an excuse not to give the agency more tools to protect miners.

"I do not excuse MSHA's failures," Rahall said. "But the Congress should not withhold effective, lifesaving legal authorities from the agency as some kind of penalty -- because ultimately, the only people penalized by that cockeyed approach will be our miners."

Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.