~ VIII 5] = Summary of Recommendations Tne following recommendations apply to alpvha-emitting hot particles where a hot particle is defined as a particle that contains sufficient activity to deliver at least 10060 rem/yr to the surrounding lung tissue. For isotopes having hali-lives greater than one year, this would correspond to particles containing at least 0.07 oCi of alpha activity. ®? & is recommended that: l. For occupational exposure MPEP?B = 2 not particles MPCa for Pu-239 = 3.3x10-16 uciyn1®? --2. For non-occuvational exposure MPLP3 = 9.2 hot particles MPCs Zor Pu-239 = 9xl0-18 uci/mi®? 87/ These varvticulates would consist of compeunds of Pu and tne other actnises which fall into Class Y material in the ICR Task Group Lung Mocel. These materials wouis be retained for years in the lung. See for example, ICRP Publication 19, O95. cit., 3. 6. Since oniy sarticles in the size ranca of 5 u and Dalaw in Giameter woulc be deposited in the @een ressiratoryv tissue, this in eliact saris an unoer limit for tne particle size of interest here Ef the nalf-life is less than or clss2 to l year the Limit of 9.97 3Ci can be adjusted usoward through .asprovriate calculations. fi/ Tails MPa asolies for sarticles containing 0.07 sci of Dy-233. For garcticles containing more than 9.97 oCi the Mrln Could na insraasad sropertionately. For particles Tontaining less than 0.07 voCi the existins s2Cysaxlo7li cCi/n} would apply. The MPCqa for hot garticlas of otner isotopes and mixtures af isotoses shoulda be astablisnad on a similar bisis with considaration given to the half-lifa of the isotope. a9/ Tate \,