The relative significance of dust ingestion during and after short-term inhalation exposure to a zinc chromate aerosol has been studied. Two groups of rats were exposed in the same dust cloud, one in open wire cages and the other in fiber glass tubes. The chromium excretion during the following 2 1/2 days was 8.4 times higher in faeces and 5.5 times higher in urine in the animals exposed in cages, compared with those exposed in tubes.