Document mmDVBQqdmDo3qQmJarp3QBVJd

mmmmm threatening and' may, induce, at worst, only some slight discomfort. If any obstruction of the lungs is pres ent, cigarette smoking is much more likely to be the cause. Since it is not a tumor or a virus or a bacteria-caused ailment, but a reaction of lung tissue to the presence of mineral fibers, it can be diagnosed with 100 percent certainty only by biopsy. X-rays may show white lines indicating abnormalities, but they usually look the same as they do in a variety of other illnesses. Dr. Ray mond Murphy, an occupational lung specialist at Boston's Faulkner Hospital, calls X-ray intepretation in cases of slight or early asbestosis "one of the most subjective in medicine." Dr. Barry Levine, a lung specialist at Harvard Medical School, agrees: "It's a rare phenomenon to find true asbestotic disease... A person with obstructive lung disease (a cigarette smoker's disease such as emphysema) can be read as having an X-ray com patible with asbestosis." It wasn't until the 50s and 60s that studies were published in England and the United States implicating asbestos as a cause of lung cancer and mesothelioma, a rare cancer of the lining, of the lung. But even then, cigarette smoking was far more heav ily implicated. The first study was conducted by Sir Richard Doll of Oxford University, internationally honored for his epidemiological studies conclusively proving cigarette smoking causes lung cancer. Doll studied workers with at least 20 years exposure to the mineral in textile plants, and found the disease was experiencing 10 times the lung cancer deaths of non-asbestos workers at tahe same age. Selikoff tracked down in the 60s most of the workers who had been carried on the rolls of an asbestos workers union, and found by 1973 the group had experienced a death MICRO ANALYTICAL ANALYTICAL MICROSCOPY SERVICES Specializing in Asbestos Analysis of air filter samples by Electron Microscopy State-of-the-art facilities for only the very best in Pollution Analysis Cambridge S-250 40 KV Scanning Electron Microscope Orlec Systems 5000 Energy Dispersive X-Roy JEOt 200CX Analytical transmis sion Electron Microscope X-Roy Diltroclion Particle Size Distribution Sub-Micron Foreign Particle Identification For more information Phone (904) 375-3286 or write P.O. Box 1154, Gainesville, FL 32602 rate 50% greater than the average white male. In retrospect, these studies were seriously flawed, even primitive by current scientific standards. Tb begin with, the comparison to the average white male provided an inadequate ` 'control' '--a group sufficiently similar in socio-cultural characteristics as the cohort studied so that any sharp dif ference in experience can be logical ly related to the factor, asbestos in this instance, under study. Even in the 40s and 50s, white collar workers were much less likely to be smokers than blue collar workers. Moreover, the general health of the average white male was much more likely to be better, because of access to better nutrition and medical care, than that of black workers who were dispropor tionately represented in the asbestos trades. Further, almost all the World War D workers had either been too old to be drafted, or even more significant, unable to pass the physical. Another difficulty with the studies, little appreciated at the time but seen now as very disturbing was the im possibility of assembling complete cohorts, groups with all of the workers exposed in a particular workplace. Up to one third were missing in the groups studied by Selikoff 20 years later. Moreover, the assumption was made that the three different types of asbestos, chrysotile, crocidolite and amosite, although dif ferent in their mineral characteristics, the length and diameter of the in dividuals fibers, would have the same biological effects in humans. Even then, the Selikoff studies did make the central point that asbestos, while dangerous, was infinitely more dangerous in combination with cigar ette smoking. Selikoffs published studies of the time estimated the in creased risk as being 80 to 90 times higher. "(H)ad it not been for cigarette smoking, many of these deaths would have been avoided," Selikoff wrote in one paper. (In the next edition of Asbestos Abatement Magazine, Mr. Bennett will discuss the work by Dr. Selikoff mare closely and trace the develop ment of the asbestos controversy to present times.) 38 ASBESTOS ABATEMENT MARCH/APRIL 1987 GLEASON-001147