Abstract: At 11:30 a.m. on February 13, 2019, Employee # 1 was using a propane torch (weed burner) to thaw a discharge valve on a vacuum trailer that had been frozen closed. The trailer had previously been used to haul production water (brine water). Employee #2 was working nearby. After applying the open flame to the valve for approximately 30 seconds the tank exploded. The explosion was presumably the result of over pressurization of the cargo tank as a result of the ignition of hydrocarbon vapors or gases that had remained in the tank after the last load of production water had been emptied at a disposal site. Employee # 1 sustained burns, bone fractures, and was struck by shrapnel. He was hospitalized at a burn treatment center. Employee # 2 was struck by shrapnel. He was hospitalized.