Respirable silica (14808607) (quartz) exposures among concrete workers and masons in Washington State were studied. Surveys were conducted at 12 construction sites in Washington State where concrete workers or masons were working over an 18 month period from 1991 to 1993. The surveys were initiated as a result of Washington Industrial Safety and Health Act (WISHA) inspection activities related to possible health violations and were intended to determine compliance with existing WISHA and OSHA standards. Environmental and breathing zone samples were collected at each site and analyzed for quartz. Breathing zone quartz exposures ranged from below 0.06 to 2.6 milligrams per cubic meter (mg/m3). The lowest exposure was associated with sawing concrete floors in a large room with general ventilation. The highest exposures were associated with grinding mortar outdoors with electric grinders. Most quartz exposures were above the State of Washington and OSHA 8 hour time weighted average standard of 0.1mg/m3. The quartz content of bulk mortar, concrete, and concrete block samples varied from 4 to 12%. Most efforts to control quartz dust exposures, where present, were inadequate. Water suppression was used at some sites; however, this did not effectively control dust, as exposures ranging from slightly below to 2 to 3 times the standard were measured at these sites. Most dry cutting and grinding operations did not have local exhaust ventilation and were usually performed without the workers wearing respiratory protection. Workers at the sites were not informed of the health hazards associated with quartz. The author concludes that quartz dust exposures in excess of state and OSHA standards probably occur on a widespread basis for specialty trades such as concrete worker and mason. A great need for implementing appropriate measures to control dust exposures at these sites exists. Air sampling should be performed to assess the effectiveness of any adopted engineering controls and to select appropriate respirators.