d, ver ame ; ot *% I-160 = 7 (iE . oa . ee Ae owe O%: woe . »Since I have mentioned maximuin permissibte lung burdens, you are cware that there is official guidance. " 1 u Twould like to comment on it. The maximum permissible lung burden is established by equiliurating tic The International Commission on Rictological ShodaPWEET ORCS FLATTEELS o" aTaeE Tes ee uniform dose of x-rays. Protection indicates this may be greatly in error, and specifically states - in its publication 9, "In the meantime there is no clear evidence to show whether, with a given mean absorbed dose, the biological risk associated - with a noh-homogeneous distribution is greater or less than the risk re- sulting from a more diffuse distribution of that dose in the lung." (ICRP, 1966). They are effectively saying that there is no guidance as to the risk for non-homogenecus exposure in the lung, hence the maximum permissible lung burden is meaningless for plutonium particles, as are the maximum permissible air concentrations which derive from it. So there is a hot particle problem with plutonium in the lung, and the hot particle problem is not understdcd, and there is no guidance as to ‘the risk. I don't thinkthere is any controversy about that. Let me quote to you from Dr. K. Z Morgan's testimony in January of this year before . the Joint Committee on Atomic Energy, U.S. Congress (Morgan, K.Z., 1960). Dr. K.Z. Morgan is one of the United States! two members to the main Committee of the International Commission on Radiological Protection; he has been a memberof the commitlec longer than anyone: and he is director of Healih Physics Division at Quk Ridge National Laboratory. sem Uquose: “There are many things abeut radiation exposure we do not Cheers . . . : oe Toe a ee aerey ee ome om em ae em mm oh tee en 2+ rene a ee eeet TP Om ere maw a! eee ee aoe es Es te —. Saget ae wee ec eemerind SD ne beeee me few eee -om: + we wht Gen OF dete 84a ey SESETE BEY of ge 1g ~ ——ee wee m0 eee et ee OR ee ee eS EG eee OF Oe a me © 8 8 e+ ve | see a* se =e eres mee eT a oe exposure from the deposited radioactive aerosol with that of an acceptable —~