A study carried out at the National Cancer Institute in Bethesda, Maryland, has confirmed what many in the maritime industries have known from experience: such employees are at a significantly higher risk for mesothelioma than the general population.
Four researchers followed the case histories of over 4,700 civilian workers (approximately 300 of whom were women) at a U.S. Coast Guard shipyard between the start of 1950 through the end of 1964 and then followed up through December of 2001. The researchers evaluated the work histories of all subjects in terms of job descriptions and likelihood of exposure to harmful substances. Standardized Mortality Ratios, or SMRs, were calculated based on the state’s total population and adjusted for factors such as age, gender and ethnicity. SMRs are a method of calculating death rates that is commonly used by researchers in a variety of fields. It compares the death rate among a specific population to that of a general population.
This general population death rate is expressed as being equal to 1.0; therefore, a number such as 1.04 means that deaths among the specific population due to a given cause was 4% higher than that among the general population. The results of the NCI study showed that deaths due to all asbestos-related diseases among the shipyard workers were 8% greater than that of the population at large. Except for mesothelioma, however, there was no connection between the length of employment and an increase in the incidence of disease. Shipfitters, welders and cutters were those who experienced the highest mortality rates. The researchers concluded that their results were small, but significant, and were “probably related to asbestos exposure.” Asbestos was used extensively in ship construction, particularly after the S.S. Morro Castle disaster in September of 1934. The use of asbestos insulation throughout sea-going vessels was common until 1980. Conditions below decks resulted in concentrated exposure to asbestos fibers among a variety of marine workers, as there was very little ventilation; nor were these workers afforded protection from asbestos hazards.