October 22, 2004
CHEVRONTEXACO ISSUES STATEMENT ON MEDICAL REPORT PROMOTED BY AMAZON WATCH
Junk Science: Ecuador Study Authors Admit Failure To Prove Causal Link Between Childhood Leukemia and Oil Production
"Scientific Limitations of Research" Preclude "Even Speculating About Possible Causes of Childhood Leukemia" From Study says Health Expert
Activist Group Amazon Watch Distorts Data; Falsely Reports That Children Died From Exposure
October 22, 2004 - ChevronTexaco issued the following statement following the release of the most recent health claims related to the environmental lawsuit filed against the company in Ecuador:
A recently issued report, by its own admission, fails to link oil production activities to cases of childhood leukemia in the Oriente region of Ecuador. In his analysis of the claims, Dr. Kenneth Satin, Staff Epidemiologist with ChevronTexaco, concluded: "The scientific limitations of this research are extensive, so it is impossible to reach any definitive conclusions about possible causes of childhood leukemia."
The report's authors acknowledge the shortcomings of their study design and admit that their findings cannot be interpreted as demonstrating a cause-effect relationship between leukemia and proximity to oil production by stating: "The results suggest a relationship between leukemia incidence in children and living in the proximity of oil fields, although this study cannot lead to a causal inference."
The report, written by Dr.'s Miguel San Sebastian and Anna-Karin Hurtig, is their sixth attempt that fails to link cancer to oil production in the Oriente. According to Dr. Satin, in this most recent report, "The only cancer increase noted is in acute lymphoblastic leukeumia (ALL), a type of leukemia not associated with petroleum exposure, and among the most common form of leukemia found among children." Dr. Satin also pointed out the article's "fatal flaw" is that it "fails to demonstrate whether or not the children who developed leukemia were ever directly exposed to any petroleum related substances."
ChevronTexaco is a defendant in a lawsuit sponsored by U.S. lawyers and supported by environmental activists including AmazonWatch, alleging environmental and health damages resulting from the involvement of Texaco Petroleum Company (Texpet) as a minority partner in an oil consortium with Petroecuador before Texpet exited all oil-producing activities in Ecuador in 1992.
In his analysis, Dr. Satin detailed a variety of significant technical problems with the recently reported study:
- Wrong Type of Leukemia - There are two major types of leukemia discussed in the study: acute lymphoblastic/lymphocytic leukemia (ALL) and acute myeloblastic leukemia (AML). Benzene, a component of crude oil, is associated with AML, but not with ALL. Yet a large majority of the leukemia cases cited in the article were of the ALL variety - for which there is no proven link to benzene or crude oil.
- No Evidence of Exposure - The study design used did not require demonstrating that children were either exposed or unexposed to oil-production activities. Exposure was assumed based on residence in four counties, no matter how far away in a large county a certain child may have lived from oil facilities. This likely caused a potential bias in the direction of overestimating the cancer rates among children in the "exposed" areas.
- Inconclusive Number of Cases - The authors found only eight instances of AML in the oil producing study areas, and their own data table shows that the measurement of relative risk for that population is inconclusive.
- No Adjustment for Other Factors - Among the factors often associated with leukemia are race, lifestyle practices, ionizing radiation (such as X-rays), pesticides, and several genetic conditions. None of these contributing factors were taken into account in the design or analysis of the study.
Further, in its press release announcing the results, Amazon Watch falsely stated that the article reports that "91 children have died from cancer." In fact, the study does not indicate whether any of the children have died, and the figure of 91 includes children both from the four counties studied and from a control group of children who do not live in oil-producing counties. Amazon Watch further distorts the authors' findings when it describes eight instances of AML leukemia as a "cancer outbreak," while the authors' own data table shows that the measurement of relative risk for that population is inconclusive.
The study is further undermined by the fact that the authors cite as references the plaintiffs and their supporters, including the Amazon Defense Front, Amazon Watch, Acción Ecológica and Rainforest Action Network among others, all of whom clearly have a bias that taints the study. The authors also repeatedly reference their own previous studies, several of which have been criticized by respected medical scientists for presenting conclusions that are not scientifically valid or justified. By citing these flawed studies in their latest work, the authors are compounding their previous errors.
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