Methane Gas Explosion Blamed for West Virginia Coal Mining Accident

The West Virginia coal mining accident yesterday killed at least 25, and hope is starting to fade for finding the four missing miners alive. It's the deadliest mining accident in the United States in more than a quarter-century. A methane explosion appears to be the cause. Normally when DISCOVER covers methane scares, it has to do with the potent greenhouse gas leaking from permafrost or the ocean. But for coal miners, methane represents a more clear and present danger: Underground mines can fill up with the flammable gas, and a stray spark can light it and cause an explosion. As a result, mines are required to have giant fans that blow methane out of the working area. Methane not only appears to have caused the accident, it also held up the rescue effort.