Four people remain missing in a West Virginia coal mine two days after a huge explosion killed at least twenty-five miners. Rescue efforts have been suspended due to conditions underground at the Upper Big Branch mine. Massey Energy, which owns and operates the mine, says rescuers were forced to pull back from the search area because methane gas and smoke made it too hazardous to continue searching. Meanwhile, new revelations have come to light about repeated safety violations at the mine over the last several years. According to federal records, the US Mine Safety and Health Administration cited the Upper Big Branch mine for more than 1,300 safety violations from 2005 through Monday. Fifty citations came in the last month alone.