Winds carried the plutonium dust and smoke away from the plant and into surrounding areas. Fire investigators found no detailed records of off-site air sampling for the period of the fire. Assessment of how the plutonium moved off-site was based almost entirely on computer air dispersion modeling. The model predicts concentrations of material near ground level where people breathe the air. The most important exposure pathway was inhalation of plutonium in the air.
Particles can cause damage to tissues when inhaled or ingested.
Some plutonium was deposited onto the soil downwind of the plant and could have been ingested later by children who played in the dirt. Inhaled plutonium poses a greater human health risk than ingested plutonium, most of which passes through the gastrointestinal tract without being absorbed. However, ingestion may have been the only exposure from the fire for small children born after the event. Researchers estimated the risks of cancer to persons in the study area who were possibly exposed from the fire. The highest risks were to persons who were exercising or were outside working in areas where the plume of plutonium particles was near the ground.