NifCHELL (continned ) to tell you at what level the aluims cxide has to before the Inng vill respond that way, ‘he Alusinme oration of America, in response to an inquiry of nine, yaised the question that maybe it is not alusimm but its contaninated silican. Apparently there is the poasibillity that the aluaions oxide is not the agent with which weld concerned, I don't know, If you do want to accept the f that aluaimm ctide vhen inhaled will be fixed you can certain calculations as to the ascunt in afr which would a hasard, Yaking the original tolerance level cf 6,2x20micrograms, I tock 1/7 of that as the tolerance level, because cf the fact that the lung hes 1000 grams, as oppo te 7000 graus: cf bone, ani neglecting any difference in tiasw response, the amount of air breathed in 24 hours is 20 millicn ce and over a period of 20 years that ocuss out to 1.5010"2 06, 4 tolerance level vould be accusile in the lung if the air had a concentration 10mioregrama per ce, There again that's an assunption cf retention, PIESSET s | Wouldn't you infer that for the particles te be retained would have to fall within a narrow range of sizes, like 2 5 microns ~ found ty the Bi people, MITCHELL: There are apparently all sorts of ycu aight say arbitrary ways cf handling that ani I think the biological comnisaic just roughly state that 25 percent cf inhaled material is Bopartrast aor 136