Investigators continue to look for the cause of an explosion that damaged the coop in Clarion Tuesday and left one man severely burned. Coop safety consultant Tim Mowrer says it has not been easy finding the trigger for the explosion. He says the only conclusions they’ve come up with is that there was no natural gas leak. He says they believe it was some king of mechanical failure in the elevator, but he says they haven’t been able to determine that yet. He says, “this is going to be a tough one.” The top of the elevator at the co-op was blow off in the blast. He says the amount of the damage hasn’t been determined as the structural engineer hasn’t finished his report yet. He says that information won’t come until later today or tomorrow. The injured man, identified as Sherman Donath of Clarion, was at University Hospitals in Iowa City in critical condition.