Control of Exposure to Cobalt During Grinding of Hard Metal Blades

Abstract

Abstract The aims of this study were to develop guidelines for effective enclosures and local exhaust systems in order to reduce the cobalt exposure of workers who manufacture or maintain hard metal and stellite blades, and also to discover how the exposure level is affected by the amount of cobalt in grinding coolants. The grinding machines in three workplaces were enclosed and equipped with local exhausts, and in two workplaces coolants were replaced by a new one which, according to the product specifications, dissolves very little cobalt. Concentrations of total dust and cobalt in the breathing zone of the workers and at stationary sites and concentrations of cobalt in the workers' urine were measured before and after the changes at these workplaces. In addition, a commercial enclosure was tested. The amount of cobalt in coolant samples taken at 16 workplaces was determined. The cobalt concentrations of coolants in 12 workplaces were compared to the cobalt concentrations in the air near the machines. T...