Federal mine safety regulators were "negligent" in their oversight of the Crandall Canyon Mine in Utah where nine workers died in August 2007, the Labor Department's internal watchdog said in a report issued Monday.

The department's inspector general cited lax U.S. Mine Safety and Health Administration review of the mine's roof control plan and poor follow-up inspections of the Murray Energy operation.

"MSHA was negligent in carrying out its responsibilities to protect the safety of miners," Assistant Inspector General Elliott P. Lewis wrote in an 80-page report.

Six miners died in the Aug. 6 collapse at the Murray Energy operation. Ten days into a rescue effort to reach the trapped miners, three rescuers - including a federal mine inspector - were killed.

The initial collapse was caused by a "bump," or a blowout of mine walls and roof supports caused by increased weight from the ground above. At the time of the collapse, Murray Energy was removing coal from roof supports left behind in the 2,000-foot-deep mine.

Among other findings, the IG said that MSHA managers did not ensure that district offices enforced standard guidelines for reviewing and approving roof control plans.

Investigators found that none of MSHA's 11 districts included all 20 of the agency's administrative and quality controls in their roof-control-plan review procedures.

Also, the IG found that when MSHA reviewed the mine's roof control plan, it did not consider input from its own inspectors, the agency's expert technical support staff, or federal Bureau of Land Management officials who had inspected the Crandall Canyon Mine.

After the roof plan was approved, the IG found, MSHA inspectors did not make sure it was working or that miners were trained to implement it.

Federal mine safety regulators were "negligent" in their oversight of the Crandall Canyon Mine in Utah where nine workers died in August 2007, the Labor Department's internal watchdog said in a report issued Monday.

The department's inspector general cited lax U.S. Mine Safety and Health Administration review of the mine's roof control plan and poor follow-up inspections of the Murray Energy operation.

"MSHA was negligent in carrying out its responsibilities to protect the safety of miners," Assistant Inspector General Elliott P. Lewis wrote in an 80-page report.

Six miners died in the Aug. 6 collapse at the Murray Energy operation. Ten days into a rescue effort to reach the trapped miners, three rescuers - including a federal mine inspector - were killed.

The initial collapse was caused by a "bump," or a blowout of mine walls and roof supports caused by increased weight from the ground above. At the time of the collapse, Murray Energy was removing coal from roof supports left behind in the 2,000-foot-deep mine.

Among other findings, the IG said that MSHA managers did not ensure that district offices enforced standard guidelines for reviewing and approving roof control plans.

Investigators found that none of MSHA's 11 districts included all 20 of the agency's administrative and quality controls in their roof-control-plan review procedures.

Also, the IG found that when MSHA reviewed the mine's roof control plan, it did not consider input from its own inspectors, the agency's expert technical support staff, or federal Bureau of Land Management officials who had inspected the Crandall Canyon Mine.

After the roof plan was approved, the IG found, MSHA inspectors did not make sure it was working or that miners were trained to implement it.

Monday's report is the most strongly worded of the half-dozen studies critical of MSHA that the IG has published since 12 miners died in the January 2006 Sago Mine disaster.

Earlier this month, a scathing report from U.S. Sen. Edward Kennedy's committee called on the federal Department of Justice to conduct a criminal investigation of the deaths at Crandall Canyon.

In a previous written response and in press statements Monday, MSHA objected to the IG's use of the word "negligent," saying it was "misleading" and was "unsupported by facts or evidence."

The IG said: "MSHA's actions and inactions, taken as a whole, lead us to conclude that MSHA lacked care and attention in fulfilling its responsibilities to protect miners.

"MSHA could not show how it analyzed roof control plans, the criteria it measured the plans against, the rationale for approving the plans, that the plans were properly implemented, or that the plans continued to protect miners over time," the report said. "These deficiencies evidence MSHA's serious and systematic lack of diligence in protecting miners, and we do not believe it is misleading to use the term 'negligent.'"

Matthew Faraci, an MSHA spokesman, issued an e-mail statement saying "the confirmation by the inspector general that there was no evidence of undue influence in approving the roof plan for the Crandall Canyon Mine is welcomed."

But the IG report actually expressed concern that MSHA "could not show how it arrived at its decisions to approve these plans, nor that it did all of the things necessary to make the appropriate decision regardless of any pressure to expedite the process.

"As a regulatory agency, MSHA must be able to show that its decisions are not influenced by those it regulates and that they are sound, based on rigorous, established and documented processes and criteria," the IG report said.

To contact staff writer Ken Ward Jr., use e-mail or call 348-1702.