Determinants of Respirable Silica Exposure in Stone Countertop Fabrication: A Preliminary Study

Abstract

A preliminary study of personal exposure to respirable quartz was conducted in four shops that used a variety of wet and dry methods to fabricate countertops from granite and quartz-containing synthetic stone-like materials. Full-shift time-weighted average (TWA) exposures exceeded the ACGIH threshold limit value of 0.025 mg/m(3) for all workers who used dry fabrication methods, even for very limited time, during any part of the work shift (n = 15 person-days). The geometric mean of exposures for workers who used dry methods extensively was about 1 mg/m(3) (n = 12 person-days). Workers who operated only automated or remotely controlled stone cutting or shaping equipment had calculated TWA exposures of approximately 0.02 mg/m(3) (n = 3 person-days). Task-specific geometric mean exposures for various wet and dry manual operations were ranked based on estimated concentrations extracted from multi-task partial-shift sample results using a linear algebra procedure. Limited use of dry methods was observed in shops that had previously reported using only wet methods. These results suggest that even shops that report using only wet methods might, in fact, resort to brief use of dry methods for specific operations. Therefore, there may be reason for concern over potential overexposure to respirable quartz in all stone countertop shops.

Evaluation of workplace exposure to respirable crystalline silica in Italy

“…Mean air RCS concentration measured in these sectors (GM50.045 and GM50.017, respectively) are in line with concentrations reported in recent years in other European countries and in North America. [13][14][15][16][17] According to the 2001 industrial activity census, approximately 863 250 Italian workers are employed in construction. 11 Using our data, a reliable estimate of Italian workers exposed to silica was achievable only for a specific subsector of this activity (i.e.…”

“…This may be due to the significant decrease of airborne RCS concentrations reported in the ceramic industry over time, 14,22 and to the high variation in whether workers use dry or automated/remotely controlled working methods. 15 A number of female workers were also estimated to be exposed to RCS in this sector, particularly in the ceramic (N52458) and the artistic stone working industry (N5913). These data should be considered to build up occupational disease surveillance and reporting systems and to adopt proper compensation policies.…”

Health hazard evaluation report: evaluation of crystalline silica exposure during fabrication of natural and engineered stone countertops.

“…The company did not have local exhaust ventilation for any equipment or tasks. Wet cutting processes have been found to produce lower respirable crystalline silica concentrations than dry cutting processes in countertop fabrication shops [Simcox et al 1999;Phillips et al 2013;Cooper et al 2015]. Although employees always used appropriate respirators and used a water spray on the grinders to suppress dust, during both days of fullshift sampling, employees grinding stone with the diamond cup wheels were consistently overexposed to the ACGIH TLV, the NIOSH REL, and the OSHA PEL.…”

“…It is well known that elevated crystalline silica exposures are associated with stone work, specifically work with granite [NIOSH 2002]. Granite has been reported to contain between 2% and 60% quartz, a type of crystalline silica, by volume [Phillips et al 2013]. In contrast, engineered stone can contain a higher percentage of quartz; it can potentially contain over 90% crystalline silica [OSHA 2015a].…”

OSHA/NIOSH hazard alert: worker exposure to silica during countertop manufacturing, finishing and installation.

“…1,2 In at least some cases from Spain and Israel, workers were exposed in shops operating without dust suppression, and without respiratory protection. 2,3 While the stone industry in the United States has worked to implement dust controls to protect workers against the dangers of silica exposure, 4 studies and OSHA inspections indicate that exposure levels may not be adequately controlled in some stone countertop fabrication worksites in the U.S. 5 This Hazard Alert focuses on countertop industry worker exposures to airborne silica dust, including from quartz in stone. It covers the health effects of breathing silica dust, recommends ways to protect workers, and describes how OSHA and NIOSH can help employers effectively reduce silica dust exposures.…”