In a group of workers exposed to aluminium flake powders, blood and urine concentrations of aluminium were assessed before and after vacation. Another group was investigated after retirement. Workers currently exposed to aluminium flake powders had urinary concentrations of the metal 80-90 times higher than those in occupationally non-exposed referents. The calculated half life for concentrations of aluminium in urine was five to six weeks based on four to five weeks of non-exposure. Among the retired workers the half lives varied from less than one up to eight years and were related to the number of years since retirement. These results indicate that aluminium is retained and stored in several compartments of the body and eliminated from these compartments at different rates.