Hard metal exposures. Part 2: Prospective exposure assessment

Hard metal exposures may precipitate lung disease in exposed workers. This article reports on a project investigating the relationship between local exhaust hood air flow levels and workplace hard metal exposures. Airborne cobalt, chromium, and cadmium exposure concentrations, and ventilation system function were monitored for three consecutive days prior to installation of three new ventilation systems, and then were followed monthly for one year. Work activities included wet and dry grinding of saw blades, brazing, welding, and setup. Work task exposures were highly variable over the period of the study. Ventilation air flows failed to meet design goals due to low total air volume and poor distribution; however, worker exposures to metals were controlled in most cases. Hood design, worker acceptance, and use of the hoods were as important in controlling exposures as were exhaust hood air flow levels.