Asbestos Exposure in Navy Shipyards
The U.S. Department of Veterans Affairs has noted that during World War II, several million civilian workers in Navy shipyards, or yard birds as they were commonly called, were exposed to chrysotile, amosite and crocidolite products that were used extensively in military ship construction. In fact, specifications for naval ships indicate that nearly 300 different asbestos-containing products were used.
Amosite Pipe Insulation one of the Most Widely Used Products in Navy Ships
One of the most common uses was pipe insulation that contained amosite asbestos. Its popularity was due to its lighter weight and higher heat capacity.
In a report titled U.S. Shipyards; A History of Massive Exposure and Disease, James Fite of the White Lung Association explained that amosite insulation weighs approximately 14 pounds per cubic foot as compared with magnesia, which weighs 16 pounds per cubic foot. Amosite’s temperature limit is 750 degrees F, far surpassing the 500 degree F temperature limit of magnesia.
The superiority of amosite led to the production of amosite felt in 1934 and amosite pipe covering in 1935. Most naval vessels used asbestos containing block and felt pipe covering in new construction until 1974.
Asbestos-Containing Products were Used Throughout a Ship’s Construction
The various uses the Navy found for asbestos-containing products aboard ship made shipyard workers vulnerable to exposure during most of the construction process. Some of the places asbestos was used included as a liner beneath decks and in boilers and turbines, in piping system gaskets and packing, in the body of resistors used in electronic equipment, and in the electronic cabling used in the galley ranges.
The type of exposure that led to inhalation of asbestos fibers resulted from the need to cut the asbestos insulation sheets into custom-sized pieces that correctly fit the specific use. After the piece had been sized and cut, it would then be polished to get a smooth finish. Both of these process released asbestos fibers into the air where they were readily breathed in by workers because, at that time, these workers were not required to wear protective face masks that prevented inhalation of toxic substances. In fact, since the health risks associated with asbestos exposure were not widely known, these workers did not wear protective clothing of any kind.
Asbestos Exposure wasn’t Limited to Construction
Workers who performed routine maintenance on Navy vessels were also extremely susceptible to asbestos exposure. One very common repair was the replacement of worn out valves and flanges. The workmen would have to remove the cloth or cement insulation covering these items, which initially released asbestos into the air.
If a valve needed replacement, the asbestos-containing packing would be removed by chipping and pulling at it. This caused packing material to fly into the air and fall on the floor around the workers and on their unprotected clothing.
When a flange was replaced, the old gasket that prevented the flange from leaking was removed, and a new gasket was created by taking a hammer and hitting the gasket sheet to remove it. This action made pieces of the asbestos-containing gasket material become airborne, and these pieces eventually fell on and around these workers, causing them to inhale the asbestos fibers.