“i all of the dogs are developing cancer, itis impossible to infer what eae woukl happen at lower exposures: ey * ‘ simple proportionality docs, however, suggest that present humau stancarde are too lax by.at least a factor of tei. ae Second, becauuse the midiulton doo. is large, with tiesue injury iimoat killing the dogs; and because large numbers cf particles are involved, often ac. .¢ in conjunction; an be inferred. ‘ ° ~ it is irnprobable that the risk frorn disruptive particles And after all, this is what we need to know, since almost all Luman exposures will involve hot.particles acting independently, and if , there is a risk from these particles, it will be additive throughout the popu- . - lation; --there will be no question of a threshold burden; and there will be : a possibility that a man with an uncdetectable burden of a iew |particles will devclup a cancer as a consequence. Mor the exposures cf concern, 100¢ pecple with 100 disruptive particles each «ill suffer as many total cancers é 2: as 10,000 people with 10 parttiedes each, or as 100 people with1000 particles each.. . Plutonium In1964 "3 through 1956 contractors indicated an average total of 21 people per year with over 25% of a maximum permissible burden of plutonium (Ross, D.M., 1968). Three out of four of these exposures derived from inhalation. To be reasonab!y useful, the documentation of exoasure must go back more thas 1 yeurs, because of the Jatent pecicd for radiation induced cancer. - thy Ville of relevance to the hos pactiele problem in the buns ~ x ~~ ~ = ft . ’ Pfey pen docturnentation tee wah 1 . : ra Y hhorecent years bias tmproved greatly, but from early days * - :~ . hes been around for 25 rears, ana people have been exposed. e oo, Be Hurnan experience does not sive us the answer either. :