Document MJVpOJJ12grJM4yx5aM7V20oL

u* O/'|! 'Jv.* ?r*.'VemerkAaTleOn * , tl W f# jj ^ /.c^y- /: ,* 7. H. Etuapf j/J ..^ - .jo PLAINI lhf*;s EXHIBIT SflF-lvO JPc fflaj, 1967 Letter ft?om Division of Industrial Safety ,.. . - State of California - He: Asbestos ftist /II During the dust test on Kerch 1, soma of hie comeats vers: Hr. Bradley was . asked to read the above letter and - lie Division of Industrial Safety is an organisation Ohieh is concerned vith v accidental Injury only* They axe not qualified to make the statements In the letter and the information they gave they got second hand* The authority for this type of - ' statement would come from the California State Department of Health only* . The MAC for asbestos is 5 aUlion parts per euHe foot of partleles below 10 sic. in diameter. With the normal microscope one can see down to 1 micron* Therefore, ve count only the particles from 1 to 10 microns. The standard light field technique moans the field in which the particles are is lit up, and this is done by shining light up through the. slide into the microscope Coder certain conditions the particles have the same index of refraction as the water medium, and therefore the particles cannot be seen* vhen this oecurs, the dark-field technique is used, which means there is a disk placed directly under the slide so tha light does sot go through the specimen but around the perimeter, and essentially, ligx is reflected off the particle rather than passing through the particle. The tain "phase contrast" means there is a contrast difference between the particle and the liquid phase. In general, one gets about the same particle count with either method* It is known that there aro smaller particles below 1 micron, and these can be oassured by higher magnifying microscopes such as the electron microscope - but so vh/ In all cases vhen one reports the particles below 10 microns, it is assumed there are &any smaller partieles that are normally not visible. The only real testing done~has been vith ardrala which were given dosages of dust with the 10 micron sise down, and these animals always got the very small particles also* Hr. Bradley said that if one tested air by itself they would find ve, 7 nany of the fine particles that are normally not reported* /PHr Bradley does not know of any case of lung cancer related to asbestoais and he said asbestos dust causing mesothelioma is very rare* Mesothelioma is essentially irritation of the linings- which- goes away when the-dust condition Is removed* - I think if the Association plans to reply to this letter it should be written by some one of authority such as Hr. Bradley, or Mr. Bradley should draft the letter for SKTH' In this case, any specific statements made should be qualified vith references to sub stanti&te the technical facts* 1 - FMS/eo cc: / 7. O'Hourks