The cause of the Sago Mine explosion is still not known, according to an independent report on the Jan. 2 blast in West Virginia, the Associated Press reports via Washington Post.com.However, mine owner International Coal Group feels that lightning probably ignited a buildup of methane in the sealed-off area.The report also states the 12 miners who died could have survived if foam blocks designed to seal off an abandoned section had withstood the blast. The 40-inch blocks were made to withstand a blast of up to 20 pounds per square inch, but the force of the explosion exceeded that.According to the article, J. Davitt McAteer, who headed the federal Mine Safety and Health Administration (MSHA) during the Clinton administration and conducted the investigation for Gov. Joe Manchin, said in his report that the blocks were pulverized.McAteer\u2019s report came out the same day the MSHA ordered all mines to strengthen the seals to 50 pounds per square inch of pressure, more than double the current standard, part of the new federal mine safety legislation, the AP reports.Raising the strength requirement will "better protect miners from explosions behind sealed areas of underground coal mines," acting MSHA Administrator David G. Dye said in a statement.The nation\u2019s mine operations have until Sept. 1 to submit revised ventilation plans focusing on air circulation and mitigating dangerous methane gas, the AP reports.The AP reports there are still troubling questions without answers, according to McAteer. "We have miners in mines today, and every time a thunderstorm comes by, are we at risk? The answer is we don\u2019t know," he told the AP.State and federal agencies have not yet released their investigative findings on Sago.Compiled by Paul KersteinKeep checking in at our Security Feed page for updated news coverage.