Document 6RxxEB818JNGLKpoJqyBv30pE

I r --> tit-- "1 v ' k-*` iriHw i English asbestos workers with over 20 years of employment was reported by Merewether and Price1^ in 1930. Noro^^ noted that the incidence of asbestosis was 65 percent in 167 asbestos workers studied by X-ray. Selikoff et al. 19? investigated 1,522 asbestos insulation workers in the New York-New Jersey metropolitan area. Among 392 individuals examined more than 20 years from the onset of exposure, X-ray evidence of asbestosis was found in 339. in half of these, the asbestosis was moderate or extensive. In individuals with less than 20 years of exposure, radiological evidence of asbestosis was less frequent and when present, was much less likely to be extensive. 2.1.2 Pleural Calcification and Plagues Pleural calcification resulting from exposure to asbestos 120 i6 usually bilateral and affects the parietal pleura. 193 Selikoff stated that bilateral pleural calcification involving the diaphragm is diagnostic of asbestosis. Thi6 pleural calcification can be readily identified by X-ray.117 Kiviluoto120 discovered 499 cases of pleural calcifica tion during a community X-ray survey of 6,312 adults in the Kuu6jari commune in Finland. In Ilomantsi commune he found no such calcification among 7,101 adults. He observed that the Kuusjari commune contained an asbestos mine and suggested that these people had been subject to a localised environmental asbestos exposure. This investigator 121 also observed 77 cases of pleural plaques out of 35,000 routine chest X-rays. The case histories of these 77 revealed that 52 had previous BOOO 1*19 i PRODUCED BY FORD