"The explosion was the result of failures of basic safety systems identified and codified to protect the lives of miners," the McAteer report said.
"The company's ventilation system did not adequately ventilate the mine," the report said. "As a result, explosive gases were allowed to build up.
"The company failed to meet federal and state safe principal standards for the application of rock dust," it said. "Therefore, coal dust provided the fuel that allowed the explosion to propagate through the mine.
"Water sprays on equipment were not properly maintained and failed to function as they should have," the report concluded. "As a result, a small ignition could not be quickly extinguished."
McAteer's team of legal, technical and public health experts also blamed the erosion of three key layers of protections intended to protect miners:
| Massey's own mine safety examination system broke down. Safety hazards were either not documented in mine record books or were not corrected if company foremen noted them.
| MSHA "failed to use all the tools at its disposal" to force Massey to comply with federal health and safety laws.
| The state Office of Miners Health, Safety and Training "failed in its role of enforcing state laws and serving as a watchdog for coal miners.
The report cites previously secret testimony from hundreds of witnesses, physical evidence gathered from the mine, analysis of data collected by the independent team, and private interviews conducted by McAteer separate from the work of a joint federal-state investigation.
A variety of new information is revealed in the report, including some disclosures that could eventually prompt more criminal charges.
The report recounts testimony in which two miners allege their foreman, Jeremy Burghduff, did not conduct required safety examinations the day of the explosion. And, the report says that on many previous occasions, data obtained by investigators showed that Burghduff's methane detector was turned off when he was supposed to be checking for explosive gases in the area where methane that fueled the blast could have accumulated.
McAteer's team also reports that Gerald Pauley, the state's main inspector assigned to Upper Big Branch did not always complete his inspections of the site and had not examined the crucial longwall section since Dec. 15, 2009.
The report recounts Massey's long-troubled history of mine safety and environmental disasters, and concludes the company -- set to be bought next month by Alpha Natural Resources -- has "an inadequate commitment to safety ... coupled with a window dressing safety program."
"The story of Upper Big Branch is a cautionary tale of hubris," the report says. "A company that was a towering presence in the Appalachian coalfields operated its mine in a profoundly reckless manner, and 29 miners paid with their lives for the corporate risk-taking."
The report proposes a long list of reforms, including more resources for regulatory agencies, tougher enforcement of existing safety standards, and beefing up of those rules with new legislation.
McAteer urges the coal industry to put as many resources into improving mine safety technology as it has into mine production advances and says lawmakers should make corporate officials more accountable for safety violations.
And, the report calls for an overhaul of the way serious mining accidents are investigated in the first place, allowing for a more public and transparent process.
McAteer's team also blames the disaster in part on the coal industry's longstanding influence on West Virginia politics.
"The reality that powerful industries and their leaders cast long shadows over the state's government is not unique to West Virginia, nor is it unique to the coal industry," the report says. "It is a problem facing regulators of any large industry.
"But, with a powerful national lobby, the coal industry poses unique challenges for small state agencies that try to regulate it with inadequate resources," the report says. "For those dedicated safety officials and for the workers whose lives hang in the balance, the politics of coal must be acknowledged in any discussion of workplace safety and a commitment must be made to ensure that the public interest -- miners' safety -- is the foremost consideration."