sae SA ee ie ne eR Ot 6 ie re man RONEN thn SURED eeae meee | - 37 - reported by Park, et al, the beagle dog with the smallest lung burden, i.e., 0.2 uCi, developed lung cancer.°' The highest burden in Table V is comparable to the lowest beagle exposure; the lowest exposure in Table V, the 19 cases with lung burdens in the 0.024 uCi range are only an order of magnitude less than the lowest beagle exposure. We would suggest that this is potentially a serious situation. As of this time, none of these individuals has Geveloped lung cancer.°> However, it is only 9 years since the exocsure anc there is gooc reason to Sugeest that the latent period sposure and the cevelcoment of cancer) tp {tne time between is much longer tran this. In the beagle dog exzserinents, } 4 The t of ll vears. fu rt che lowest lung Durden was associated witn a latent perisdé ent period may be longer in man and particularly at these lower dosages and the small number of cases involved. Therefore, while these exposed individuals will be expected to supply pertinent data relative to this hot oarticle cancer risk over the next 10 to 20 vears, these exposures cive us no information at this ‘time that would warrant modifying the risk per particle or the critical garticls activity. S1/ Park, J.F., et al, Health Physics, On. cit. p. 803. 43/ Richmond, Crst, On. cit., A, on. 320-