Abstract
A small granite shed in Barre, Vermont was operated for one week without any ventilation, protecting the granite cutters by means of respirators. “Respirable” dust concentrations up to 49 mg/m3 and “respirable” free silica concentrations up to 4.4 mg/m3 were observed. Average respirable dust concentrations were 10 to 20 mg/m3 of which 15% was free silica. Under the conditions of the study, it appeared that 10 mppcf of granite dust was equivalent to about 0.2 mg/m3 of “respirable” free silica. Implications for the quartz TLV are discussed.