The bulletin outlines a special EOD diving, recovery and disposal operation in the Tokyo Bay in 1956. At the end of WWII the Japanese hastily dumped thousands of munitions including CWM filled ones in nearby waters. In one instance they dumped 177 mustard filled bombs in a shallow water area ranging in depth from 30 to 40 feet. After being submerged for over 10 years they were almost forgotten about until Japanese salvage divers happened upon them when they were searching for scrap metal. The U.S. military was brought in to assess the situation. They decided that it would be best to recover the bombs and dispose of them "properly" by dumping them in much deeper waters.
A method of recovering the 140 pound mustard filled bombs had to be designed. Due to corroded and battered condition of the bombs, the potential for leakers was great. To recover the bombs from the sea, the Navy decided to construct cylindrical steel cans with handles and lids to contain the bombs before hoisting them to the surface. Divers loaded the cans by pushing them onto the bombs, tail first, before securing the lid. The cans themselves were designed to hold water, which added to the overall weight but helped to protect against the escape of mustard. In actual use however, the cans failed to provide the full amount of safety as welds broke in a few instances.
Divers developed a system for recovering the munitions, which included stacking the canned munitions like firewood on the sea bottom before they were lifted to the surface. This worked fine until a storm came along one day and caused the pile to topple over. Lines were then brought in to secure the cans in place until all of the munitions were ready for hoisting. Hoisting the water filled cans proved almost as complex. Multiple barges and a lifting crane were brought in to pull the items from the sea. The crane proved too cumbersome and awkward and was soon abandoned for a davit and winch system mounted on a boat.
The mustard filled munitions were then carefully brought on a barge where they were stacked in the upright position. The deck of the barge was lined with dunnage and calcium hypochlorite as a protective measure in case a leaker was recovered. Personnel wearing protective clothing secured the cargo for transport and "there, beyond the 2,000-fathom line, the cans were pushed over the side".
To view a copy of the 1956 4-page bulletin select the download option below.