The investigators also took issue with the conclusion offered by Massey officials — that the explosion occurred when a giant burst of [[methane]] bubbled from the ground, a natural event that would have been impossible to predict or control. The damage inside the mine was not consistent with that theory, investigators said, as only two workers who died had methane in their lungs. The report went on to say that “If, as Massey investigators maintained, one million cubic feet of methane had been suddenly released, the result would have been a five million cubic foot flame going across the face and throughout the tailgate entries in both directions. Evidence found during the investigation does not suggest a force of this magnitude.”<ref>Sabrina Tavernise, [http://www.nytimes.com/2011/05/20/us/20mine.html "Mine Owner’s Negligence Led to Blast, Study Finds"] NY Times, May 19, 2011.</ref>
The report also noted that most of the miners killed had [[black lung]] disease, or coal workers’ pneumoconiosis (CWP). The report stated: "Of the 29 victims, five did not have sufficient lung tissue available to make a determination relating to CWP: two due to massive injury and three due to autolysis. The remaining 24 victims had sufficient tissue for examination. Seventeen of the 24 victims’ autopsies (or 71 percent) had CWP. This compares with the national prevalence rate for CWP among active underground miners in the U.S. is 3.2 percent, and the rate in West Virginia is 7.6 percent."<ref>Ken Ward Jr., [http://blogs.wvgazette.com/coaltattoo/2011/05/20/mcateer-report-ubb-black-lung-findings-alarming/ "McAteer report: UBB black lung findings ‘alarming’"] Coal Tattoo, May 20, 2011.</ref>
May 20, 2011.</ref>
==History of Safety Violations at the mine==