Document DdZa5YmEMXyDK0ZxQnBw4x3wn

14256997033 2002-02-26 19:09:21 (GMT), page 24 23 The QAMA McGill researchers used available dose measurements from 1949-1966, which were measures of"total" particles collected by midget impinger.fGibbs and Hui 1971) This method cannot distinguish fibers from other dust particles (silica, other "non-toxic" dusts, etcetera).(Egilman ami Reinert 1996) Unfortunately only the fibers, which may or may not be captured in the total particle measurements, cause disease. The dose estimates from the QAMAMcGill mine studies are wrong and systematically overestimate the actual exposures. To the extent that accurate estimates of exposures of the Canadian miners and millers can be made, they indicate that the miners were, in all likelihood, exposed to fewer fibers than were the South % Carolina textile workers, rather than the other way around, as the QAMA-McGill researchers suggest. However, much like the man who refused to replace his broken watch because it was correct twice a day, the researchers failed to give up their flawed measurement technique. As early as 1951, QAMA researchers realized that the calculation of dose estimates for Quebec miners was impossible. As Vorwald, a consultant to the QAMA, wrote to Cartier, the director ofthe QAMA industrial disease clinic in Thetford Mines, "Last week, while in Washington, I had the opportunity to discuss our program concerning the epidemiology of pulmonary cancer in subjects exposed to asbestos dust and to present the problem which you posed regarding job classification. I agree with your views. Certainly it is an impossible task to tabulate the various jobs on comparable scientific data, since such data does not exist Therefore the code suggested by both you and Ken [Smith medical director ofJohns-Manville] should be used." [Emphasis added] (2001c;Vorwald 1951) Cartier later served as a consultant to the QAMA-McGill researchers. What was impossible in 1951 became the dose reconstruction of 1971.(Gibbs and Hui 1971) Dr. McDonald was aware ofthis problem no later than April 23, 1969. During the discussion period following his chairing of a session on asbestos measurement 23