Mesothelioma Among Oil Refinery Workers
Throughout the last decade, a controversy has been raging about the level of asbestos health risks to oil refinery workers. A series of academic papers by Italian researchers and responses by international critics, reveal much about the perennial debate over asbestos.1 In 1994, Dr Valerio Gennaro’s team concluded that "exposure to asbestos in oil refineries causes pleural mesothelioma. This is the first study to find an excess of pleural mesotheliomas among oil refinery workers exposed to asbestos." Based on the research they carried out in Genoa and La Spezia, towns in Northern Italy, the scientists said: "In our opinion, pleural mesotheliomas should be considered an occupational disease among oil refinery workers since the use of asbestos has been widespread in this work and many of the workers share the same environment."
Dr. Otto Wong doubted the validity of these conclusions which he alleged were based on faulty statistical analyses and interpretation weakened by reliance on data from ill-chosen refineries. The scientists’ reply included details about the types of asbestos fibers and products used in U.S. and Italian oil refineries and the levels of exposures experienced by the workers. From new information obtained, they estimated that between 1948, when the refinery in Genoa was built, and 1960/61 a total of 659-791 tons of amosite asbestos had been used. After a detailed refutation of Wong’s critique, they concluded:
"The letter of Dr Wong suggests a possible overestimation of pleural tumor risk among oil refinery workers. Nevertheless, underestimation might be possible. In fact, it is possible that the pleural mesothelioma of some workers could have been erroneously diagnosed on the death certificate, as either lung tumor or other respiratory diseases."
Two years ago, another paper was published which extended the focus of the research to include lung tumors. Gennaro’s team reported that:
"96-100% of the mesotheliomas and 42-49% of the lung tumors arising among maintenance workers were attributable to asbestos exposure. Our new analysis, estimating two cases of asbestos-related lung cancer for each case of mesothelioma, confirms published findings on the magnitude of asbestos-related tumors in oil refineries."
Some of the many well-mannered but vociferous objections to these conclusions came from scientists employed by the Shell Oil Company. Drs. Tsai, Waddell and Ransdell, maintained that Shell’s research showed "no indication of an association between lung cancer and length of employment as maintenance workers."
In the context of this article, perhaps the most useful document is the Letter to the Editor by Ludwig, Madeksho and Egilman. The authors explain that the fierce controversy over the health risks to this relatively small group of workers is part of a larger debate:
"The primary strategic goal of the (petroleum and chemical) companies was to create an aura of "controversy" concerning the scientific basis for the alleged health effects by confusing the epistemology of causation, and corrupting medical literature through intentional misdesign, suppression and misrepresentation of research. The companies, their lawyers and consultants fabricated a debate concerning the issue of whether or not disease increases in exposed populations were real or "controversial" [Hill and Knowlton; Solon, 1973; Tweedale, 2000; Wolff, 1998]."
Explaining how industry appropriated "scientific" methodologies to suit its need, Ludwig et al discuss the practice of "tolling," which shields
"large corporations from the discovery of adverse health effects of exposed workers, health and safety regulations, liability and oversight [Goldfarb, 1978]. In some instances, their study design manipulation is so effective that results indicated that exposures to asbestos, benzene and other known toxins increase life expectancy and reduce disease morbidity… These manipulations help explain why the European epidemiological studies are positive while the American studies tend to be negative."
September 11, 2002
1 Pleural Mesothelioma and Asbestos Exposure Among Italian Oil Refinery Workers by Valerio Gennaro, Marcello Ceppi, Paulo Boffetta et al Scand J Work Environ Health 1994;20:213-5
Pleural Mesothelioma in Oil Refinery Workers by Valerio Gennaro, Marcello Ceppi, Vincenzo Fontana et a; Scand J Work Environ Health 1995;vol 21, no 4
Pleural Mesothelioma in Oil Refinery Workers Letters to the Editor by Otto Wong Scand J Work Environ Health 1995;21:301-9
Mesothelioma and Lung Tumors Attributable to Asbestos Among Petroleum Workers by Valerio Gennaro, Murray M. Finkelstein, Marcello Ceppi et al American Journal of Industrial Medicine 2000; 37:275-282
Re: Mesothelioma and Lung Tumors Attributable to Asbestos Among Petroleum Workers. Am. J. Ind. Med. 2000. 37:275-282 Letter to the Editor by William J. Bailey American Journal of Industrial Medicine 39:513-514 (2001)
Re: Mesothelioma and Lung Tumors Attributable to Asbestos Among Petroleum Workers. Am. J. Ind. Med. 2000. 37:275-282 Letter to the Editor by Shan P. Tsai, Louis J. Waddell, Jerry C. Ransdell American Journal of Industrial Medicine 39:515-516 (2001)
Re: Mesothelioma and Lung Tumors Attributable to Asbestos Among Petroleum Workers. Am. J. Ind. Med. 2000. 37:275-282. I. Reply to Tsai et al's Letter to the Editor and New Evidence by Valerio Gennaro, Fabio Montanaro, Marcello Ceppi et al American Journal of Industrial Medicine 39:517-521 (2001)
Re: Mesothelioma and Lung Tumors Attributable to Asbestos Among Petroleum Workers. Am. J. Ind. Med. 2000. 37:275-282. II. Reply to William J. Bailey's Letter to the Editor by Valerio Gennaro, Fabio Montanaro, Marcello Ceppi et al American Journal of Industrial Medicine 39:522-523 (2001)
Re: Mesothelioma and Lung Tumors Attributable to Asbestos Among Petroleum Workers. Am. J. Ind. Med. 2000. 37:275-282. Letter to the Editor by Erich R. Ludwig, Larry Madeksho and David Egilman American Journal of Industrial Medicine 39:524-527 (2001)