The U.S. Coast Guard recently conducted a marine casualty investigation into an uncontrolled release of isobutane from a 2-inch cargo tank pipe aboard a pressure barge certificated to carry flammable cargoes. The direct cause of the incident was traced to the failure of the studs of a ball valve installed on a cargo tank’s gauging pipe which sheared off and caused the ball valve to separate from the cargo pipe. The affected ball valve, manufactured by Ohio Valve Company, was supplied…