The presence of aflatoxin (55598806) in respirable airborne peanut dust was investigated. Peanuts were commercially grown, harvested, dried, handled, and shelled. The peanuts were dug, inverted in a window, and then exposed to the sun to dry for 3 to 7 days. Samples with visible Aspergillus-flavus mold were processed separately from uncontaminated peanuts. In the shelling process, air used to remove the shells and dust from peanuts was directed toward the air samplers. Particulate samples were collected with an impactor and a sampler and maintained at a constant flow with an electronic flow controller. Particles of 1:1 micrometer aerodynamic diameter were collected on a filter, at a constant temperature of 70 degrees-C and a constant relative humidity of 50 percent. The dusts were weighed accurately, extracted with chloroform and analyzed for aflatoxin-B1 (1162658) by thin layer chromatography. Concentrations were measured using a densitometer. Twelve peanut dust samples were tested for content of aflatoxin-B1. Dust concentrations ranged from 10.5 to 65.1 milligrams per cubic meter, and airborne aflatoxin-B1 concentrations reached a maximum of 7.6 nanograms per cubic meter. The aflatoxin content of the dust was directly proportional to the aflatoxin contamination of the lot of bulk peanuts. No aflatoxin was found in the dust from uncontaminated peanuts. Dust collected from the handling and shelling tests had only about one half and one ninth as much aflatoxin, respectively, as the bulk peanuts. The authors conclude that most of the contaminated dust is removed before shelling. Hence, the air in the peanut processing area is not hazardous.