[Efficacy of preventive measures for reducing professional disorders due to pumice powder]

The analysis of the incidence of pumice pneumoconiosis in the period 1970-2002 allows to evaluate the positive effects, particularly on the deadly forms of the disease, of the technical interventions aimed at reducing dusts. The main interventions in the field of the workmanship of pumice were made at the beginning of 70s, with the introduction of electrofilters in the working cycle and the change of the pumice desiccation system, from plate ovens to closed-cycle rotating ovens. This eliminated the need for manual shedding of pumice stones on oven plates. That duty had caused, between 70s and 80s, an high incidence of deadly forms of pneumoconiosis, which dramatically decreased with the reduction of workers exposed to the above risk. A comparison between the period 1970-75 (before preventive technical interventions) and the period 1976-2002 clearly shows an evident decrease both of deadly forms of pneumoconiosis and of acceptance of appeals for professional silicosis.