A large explosion struck a coal mine in northern Iran today, trapping dozens of miners and killing at least two. <br/><br/>Ambulances, helicopters and other rescue vehicles raced to the scene in Iran's northern Golestan province as authorities worked to determine the scale of the emergency. <br/><br/>The IRNA news agency quoted Golestan provincial emergency management department head Sadeq Ali Moghadam as saying that 40 to 50 people are believed to be trapped in the mine outside of the town of Azadshahr. <br/><br/>Iranian state television said two workers had died. Several officials blamed the explosion on accumulated gas and said it was affecting rescue efforts. At least 25 people who had entered the mine to try to save those trapped had to be taken to the hospital after inhaling the gas. Iranian news reports said the explosion happened while workers were changing shifts.