Abstract: Employee #1, a diver, was cutting down the interior bulkhead of a compartment that extended from the main deck to the keel. The compartment behind the bulkhead Employee #1 was cutting is divided by a deck that is 33 in. below the main deck. Since the ship is made of approximately 1/4 in. steel plate, Employee #1 cut approximately 2 in. into a compartment that could not have been checked for gas. Poor visibility hindered the operation. Employee #1 cut into a gas pocket of either methane or hydrogen that was ignited by his cutting torch and exploded. He sustained major head injuries and was killed. The gas could have formed by decaying organic material in the compartment or by fumes left when the vessel sank.