Eminent French
toxicologist Henri Pezerat, Ph.D., exposes bias in D. M. Bernstein's asbestos-industry-funded studies.
Pezerat H. Chrysotile Biopersistence: The Misuse of Biased Studies. Int J Occup Environ Health 2009; 15:102-106. Bernstein claims his rat studies show chrysotile asbestos has a short
half-life in humans and, therefore, is only a weak carcinogen.
But Pezerat reveals that Bernstein's "early studies were funded by
Union Carbide Corporation, the former part owner of a chrysotile mill and mine which today holds millions of dollars of asbestos liability; while later studies were funded by asbestos producers through [the Chrysotile Institute, the asbestos industry's lobbying arm]."
Id. at 102.
How fibers are treated before they are tested significantly affects their half-life (biopersistence) in the lungs. Bernstein appears to articifially reduce half-life by manipulating the asbestos fibers before testing them. Id. at 104. First, Bernstein selects long fibers through water sedimentation. Water sedimentation hydrates and oxidates the asbestos fibers, diminishing the fibers' surface activity and damaging their structure. Then Bernstein grinds the fibers by rotating them at high speeds, "throwing them against a 'durable grinding surface.'" Id. Because hydrating and grinding "can seriously damage fiber structure and shorten half-life in the lungs, this preliminary treatment raises serious questions." Id.
Pezerat points out that, "Bernstein's findings contradict results obtained by independent scientists." Id. at 102. In fact, Bernstein's "findings on the length of chrysotile half-life in the lungs diverge widely from those found by other research teams; Bernstein's time lengths are always shorter." Id. at 104.
Pezerat concludes that Bernstein's studies "lack scientific rigor and credibility." Id. at 105. "Bernstein's results do not constitute scientific progress. Quite to the contrary, they are being misused by the international asbestos producers' lobby to suggest that chrysotile is harmless. This dangerous assertion particularly compromises the health of workers in developing countries where living and working conditions. . . add to the morbidity and mortality resulting from exposure to chrysotile." Id. "[A]pproximately 100,000 people die of asbestos disease each year." Id. at 102.
"This paper serves as an example of how corporations have used science to achieve profit growth and escape liaiblity at the expense of dead and injured workers." Id. at 102.
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