Castor beans contain the extremely toxic protein, ricin. The beans contain 1 to 5% ricin that can easily be separated. The localized dispersal of powdered ricin could potentially affect large areas due to transport in dust. The lower density of this toxic protein relative to soil particles might facilitate greater transport in dust. In this study, soil samples containing ricin or the non-toxic surrogate, peanut lectin, were placed in a small dust-generating device and dust fractions collected. Samples of a Brownfield loamy fine sand and a Pullman clay were mixed with 5% powdered castor bean extract or peanut extract. Subsamples (5.00 g) of the soils were placed in a dust generator and dust fractions collected. Coarser sand fractions remained in the dust generator, whereas, progressively finer particles were collected in trap1, trap2, trap3, and trap4. Trap3 and trap4 contained water to collect the smallest particles. Most (55% to 98%) of the peanut lectin or ricin moved as a fine dust and was collected in trap3 and trap4. Because of the finer texture, the Pullman soil (49%) generated more dust than the Brownfield soil (16%). Ricin or peanut lectin was 6 to 8 times more concentrated in the dust compared to the original soil sample. The inhalation of dust generated from ricin-contaminated soils could pose a serious hazard.