The lung dissolution rates for PuO2 were determined using a 100 day in vitro experiment. A very small amount of the PuO2 rapidly dissolved with a half-time of approximately 10 days, while the majority of the material (>99%) dissolved with a half-time
of approximately 5 . 105 days. This dissolution half time is significantly longer than what is recommended by the ICRP, and would result in higher
calculated doses for inhalation intakes of PuO2 than those currently estimated by the ICRP 66 human respiratory tract model for radiological protection.