The USS O-4 (SS-65) was one of 16 O-class submarines built for the United States Navy during World War I. It was laid down on 4 December 1916 but came to serve during both World War I and World War II. Even though it was built early, when asbestos was not such a prevalent material, the USS O-4 was decommissioned in the middle of its service, in 1931, so the carcinogenic mineral may have been subsequently present inside of it. The USS O-4 was decommissioned in 1945 and afterward scrapped.
Asbestos is a dangerous mineral that, when inhaled, can cause severe pulmonary issues and even cancer. Prior to the 1970s, all US Navy ships including aircraft carriers, cruisers, destroyers, battleships, auxiliary crafts, and submarines, were filled with asbestos from stern to bow. Those who worked on and around pipes, ducts, valves, and gaskets were often exposed to tremendous amounts of asbestos fibers.