Document bak2jzDjVk58rp3rV7anOr0X0

PRATT EXPOSURE TO ASBESTOS DUST (Continued) He also showed that the incidence of fibrosis increased in direct proportion to the number of years of exposure, reach* ing 3IX in the group of workers employed in the industry for 20 years or store. In 1931, as a result of this study. Great Britain passed regulations to control the dust and exposures better than had been done previously. This was the first time that attests were made to control the exposure of humans to asbestos dust. On a survey in 1949 in South Africa, a larger mining area for asbestos, an American physician found children developing asbestosis before the age of 12. Zn checking on.their activity, he found that they were employed in a mill and their job was to stand in large jute bags and pack the asbestos fiber down with their feet as the material was being put into the bag. Zn I960, 2 physicians working independently, one in Tinland, and one in South Africa, discovered asbestos bodies in the lungs of people who lived near asbestos factories but did not work in them. This was the first indication that asbestos eould be inhaled without direct occupational exposure. Many studies have been done since this to sub* stantiate the- prevalence of asbestos fibers in the atmosphere. DUP 0903186 120988