In this study, the authors characterized exposure to asbestos in the population of New Caledonia, an area where a high mesothelioma incidence was found to be associated with the use of a tremolite-containing whitewash on dwellings. The authors collected airborne samples from various sources. Lung tissue samples or bronchoalveolar lavage fluids were available for 80 subjects, who were interviewed regarding their residential and occupational histories. The authors analyzed all samples by analytical transmission electron microscopy. Results indicated that the use of the tremolite-based whitewash may generate high airborne fiber levels and result in asbestos lung contents comparable with those observed in occupational settings. The highest airborne tremolite concentrations were reached during sweeping in whitewashed houses. Lung concentrations of tremolite fibers were significantly higher in subjects exposed to the whitewash than in unexposed subjects, and the concentrations increased with the duration of exposure.