Written by Greg Arnold, DC, CSCS. Workers exposed to synthetic rubber production had a 16% higher rate of leukemia than expected.
Regarded as “ubiquitous and indispensable” to the function of society for over 100 years, world production of rubber totaled 23.3 million tons in 2007 (13.6 million tons of synthetic rubber, 9.7 million tons of natural rubber). Since its’ first uses at the turn of the 20th century, rubber has undergone several advances, one of the most notable occurring in the 1930’s with the invention of a synthetic rubber called styrene butadiene rubber (1).
But this technological advance has not come without cost as workers exposed to styrene butadiene rubber during its’ production have experienced higher levels of death from leukemia than the general population thanks to research conducted on nearly 18,000 North American workers from 1944-1991 (2). A follow-up study done in 2005 that added another 7 years of data to the original study (3) found deaths from leukemia were 16% higher than expected, though the researchers stated this increase was “small and not limited to a single form of leukemia.” The researchers also suggest that this increased risk of leukemia occurred in workers with more than 20 years of work in the synthetic rubber plants and exposure to styrene butadiene rubber.
In addition to the increased leukemia risk, the researchers also noted an increased rate of death from colorectal cancer and prostate cancer but these deaths were found not to be related to exposure to styrene butadiene rubber production but were instead found to be due to chance.
While the researchers have been able to identify a possible increased risk of leukemia from exposure to styrene butadiene, they admit that they still do not know how styrene butadiene causes this increased risk (4), making any efforts at prevention difficult. In addition, the links between styrene butadiene exposure and leukemia remain inconclusive as studies of reinforced plastics workers exposed to styrene concentrations much higher than levels typically found in the synthetic rubber industry have not reported any consistent relation with leukemia (5, 6).
For the researchers, “Uncertainty remains about the specific agent(s) and about the role of unidentified confounding factors that might be responsible for the association found between employment in the synthetic rubber industry and leukemia in this study” and that “The carcinogenic mechanisms through which butadiene and styrene could cause leukemia in humans have not been established, and external epidemiological support for a [leukemia-causing] role is limited.”
Source: Sathiakumar, N., et al. “An updated study of mortality among North American synthetic rubber industry workers.” Occupational and environmental medicine 62.12 (2005): 822-829.
© BMJ Publishing Group Ltd. 2017
Posted May 21, 2013.
References:
- De Guzman D. History of the Synthetic Rubber Industry. ICIS Chemical Business 2008; 17:45.
- Sathiakumar N, Delzell E, Hovinga M, et al. Mortality from cancer and other causes of death among synthetic rubber workers. Occup Environ Med 1998;55:230–5.
- Sathiakumar N. An updated study of mortality among North American synthetic rubber industry workers. Occup Environ Med 2005;62:822-829 doi:10.1136/oem.2004.018176.
- Albertini RJ, Sram RJ, Vacek PM, et al. Biomarkers for assessing occupational exposures to 1,3-butadiene. Chemico-Biological Interactions 2001;135–136:429–53.
- Kogevinas M, Ferro G, Saracci R, et al. Cancer mortality in an international cohort of workers exposed to styrene. In: Sorsa M, Peltonen K, Vainio H, Hemminki K, eds. Butadiene and styrene: assessment of health hazards. IARC Scientific Publications No 127. Lyon, France: WHO, IARC, 1993:289–300.
- Coggon D. Epidemiological studies of styrene-exposed populations. Crit Rev Toxicol 1994;24:S107–S115.
