The analytical techniques routinely used for the mineralogical analysis of small particles, ranging from light microscopy (LM) to electron microscopy (EM) coupled with energy dispersive X-ray spectrometry (EDS), can be applied to evaluate the content of broncho-alveolar lavage (BAL) in various inorganic particles. The evaluation of the concentration of asbestos bodies (AB's) in BAL samples allows in some cases to assess an asbestos exposure not revealed through a detailed occupational inquiry, and consequently can have important medico-legal implications. However it must be kept in mind that even a very positive BAL is an indicator of exposure, but can never be considered as a proof of disease. The interest of these studies is not limited to asbestos related pathologies, but they have also contributed to a better diagnosis and understanding of the pathogenesis of unusual pneumoconiosis like aluminium induced interstitial lung disease and dental technicians pneumoconiosis.