Dose Assessment Following a 238 Pu Inhalation Incident at Los Alamos National Laboratory

Area of Science:

• Nuclear Safety
• Occupational Health
• Radiological Protection

Background:

• A glovebox breach at Los Alamos National Laboratory resulted in potential exposure of 15 individuals to plutonium-238 (238Pu) aerosols.
• Workers wore cloth masks for COVID-19 protection, complicating in vitro analysis of particle inhalation and solubility.

Purpose of the Study:

• To assess internal radiation doses for individuals exposed to 238Pu aerosols.
• To evaluate the effectiveness of chelation therapy (DTPA) in reducing internal plutonium contamination.

Main Methods:

• In vitro particle size and solubility analysis.
• Bioassay monitoring through urine sample collection.
• Utilized the Type M 1 μm AMAD model for intake and dose estimation, accounting for mask effects.
• Calculated committed effective dose (E(50)) using urinary excretion data post-chelation.

Main Results:

• One individual (P0) received two intravenous DTPA treatments, resulting in a calculated committed effective dose (E(50)) of 5.2 mSv.
• Bioassay data for the other 14 individuals indicated no significant intake or doses below 0.1 mSv.
• In vitro study results were deemed questionable for direct dose assessment due to mask interference.

Conclusions:

• The Type M 1 μm AMAD model, adjusted for mask effects, provided a viable method for dose estimation in this incident.
• Chelation therapy with DTPA was administered to one exposed individual.
• The study highlights the importance of considering protective equipment in radiological dose assessments.