Leukaemia in offshore oil workers: IOM provides advice for new research study
In 2008 a group of researchers from Norway published the results from a research study that showed an increased risk for cancers of the blood and bone marrow amongst offshore oil workers(1). The risk was clearest for two types of cancer: acute myelogenous leukemia (AML) and multiple myeloma (MM). The authors speculated that the cause of the increased numbers of these cancers was as a result of exposure to benzene, although the average benzene concentration in the air on offshore facilities is low (currently it is typically less than 0.1 ppm).
The International Agency for Research on Cancer (IARC) later affirmed the classification of benzene as a known human carcinogen, which causes AML, and where there is more limited evidence that it causes four other related cancers including MM, acute lymphocytic leukaemia, chronic lymphocytic leukaemia and non-Hodgkin lymphoma (NHL)(2).
Since then there have been a number of other scientific publications that have looked at the risks from low-level benzene exposure. Some studies suggest that there are changes to gene expression amongst low benzene exposed workers(3). Other researchers have analysed all of the published studies of workers health and concluded that these data support the view that there may be important risks below current workplace exposure limits(4). However, all the investigators agree that the current evidence is not definitive and further research is needed.
Dr John Cherrie, IOM's Research Director, is a scientific advisor to a new research study on chemical exposures and cancer incidence in Norwegian offshore oil industry workers. This work will provide much better information about exposure to benzene and other chemicals found offshore and the possible links to leukaemia and related diseases. Initial results from this study should be published later this year.
References
1. Kirkeleit J, Riise T, Bratveit M, Moen BE. Increased risk of acute myelogenous leukemia and multiple myeloma in a historical cohort of upstream petroleum workers exposed to crude oil. Cancer Causes Control. 2007 Sep. 29;19(1):13-23.
2. Baan R, Grosse Y, Straif K, Secretan B, Ghissassi el F, Bouvard V, et al. A review of human carcinogens-Part F: Chemical agents and related occupations. Lancet Oncology. 2009 Nov. 25;10(12):1143-1144.
3. McHale CM, Zhang L, Lan Q, Vermeulen R, Li G, Hubbard AE, et al. Global Gene Expression Profiling of a Population Exposed to a Range of Benzene Levels. Environ Health Perspect. 2010 Dec. 13;119(5):628-634.
4. Vlaanderen J, Portengen L, Rothman N, Lan Q, Kromhout H, Vermeulen R. Flexible Meta-Regression to assess the shape of the Benzene-Leukemia Exposure-Response curve. Environ Health Perspect. 2010;118(4):526-532.