Marsh GM, et al. - This study analyzed the data on the association between non-occupational (household and neighbourhood) exposure to asbestos and risk of pleural malignant mesothelioma (PMM). Findings revealed that non-occupational asbestos exposure-conferred PMM risks were consistent with the fibre-type potency response observed in occupational settings. A better assessment of PMM risks can be achieved in communities with ambient asbestos exposures from industrial or other sources by relating these findings to knowledge of exposure-response relationships in occupational settings.