- 31 cd a burden range of 0.5 uCi to 50 uCi the observed tumor incidence fluctuated between 0.04 and 0.3°7, All of these lung experiments involved intense exposures and a significant level of carcinogenesis. Severe damage and disruption of tissue were associated with the exposures. The most relevant lung experiment is Bair's Pu23905 inhalation study with beagles 52-54 Exposure was to particulates of 0.25 u or 0.5 u median diameter; burdens were in the uCi range. Twenty of the 21 dogs that survived more than 1600 days post 6xposure had lung cancer. - cancers were multicentric in origin. Many of these The cancers again appeared in conjunction with severe lung injury. natural incidence of the disease is small, Since the it appears that at this level of exposure the induction of lung cancer is a me certainty during the normal beagle iife span. At the same _ —_— 51/ Cember, H., Op. cit. 52/ Bair, W.J., J.F. Park, and W.Jd. ‘study of inhaled plutonium in dogs,' " (Richland), AFWL-TR-65-214, 1966 Clarke, “Long-term Battelle Memorial Institute (AD-631 690). 53/ Park, J.F., W.J. Clarke and W.d. Bair, "Chronic effect S of inhaled 232pu02 in beagles," Battelle-Northwest Laborato oY Annual Report for 1967 to the USAEC Division of Biolesy an Medicine, Vol. I, Biological Sciences, BNWL-714, 1968, ~ fl “yy pp. 54/ 2.3-3.4, / Park, J.F., et al, Transuranium Elerents ea . "Frooress in Beagle Deg Studies with at Battello-Nortiawast," Vol. 22, No. 6, June 1972, pp. fC03-c10. Health Phreicce,