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Re-suspension studies on soils contaminated with plutonium during nuclear weapons tests were performed by use of a mechanical dust-raising apparatus. Airborne dust was analyzed in terms of mass and Am-241 activities for particle sizes less than 7 mum. The AMAD was determined as 4.8 to 6 mum for re-suspended soil. Also, surface soil was characterized in the laboratory by means of sieving and microparticle classification, yielding mass and Am-241 activity distributions with respect to size. Data indicate the granularity of plutonium contamination at both major and minor trial sites. Depth profile analyses for undisturbed areas demonstrate that most (74% on average) of the americium and plutonium activity is found in the top 10 mm of soil. Plutonium and americium activities were found to be enhanced in the inhalable fraction over their values in the total soil, arid the enhancement factors were similar in re-suspended dust and surface soil. Observed enhancement factors ranged from 3.7 to 32.5.