Elevated exposures to respirable crystalline silica among engineered stone fabrication workers in California, January 2019–February 2020

Abstract

Background Workers fabricating engineered stone face high risk for exposure to respirable crystalline silica (RCS) and subsequent development of silicosis. In response, the California Division of Occupational Safety and Health (Cal/OSHA) performed targeted enforcement inspections at engineered stone fabrication worksites. We investigated RCS exposures and employer adherence to Cal/OSHA's RCS and respiratory protection standards from these inspections to assess ongoing risk to stone fabrication workers. Methods We extracted employee personal air sampling results from Cal/OSHA inspection files and calculated RCS exposures. Standards require that employers continue monitoring employee RCS exposures and perform medical surveillance when exposures are at or above the action level (AL; 25 μg/m3); exposures above the permissible exposure limit (PEL; 50 μg/m3) are prohibited. We obtained RCS and respiratory protection standard violation citations from a federal database. Results We analyzed RCS exposures for 152 employees at 47 workplaces. Thirty‐eight (25%) employees had exposures above the PEL (median = 89.7 μg/m3; range = 50.7–670.7 μg/m3); 17 (11%) had exposures between the AL and PEL. Twenty‐four (51%) workplaces had ≥1 exposure above the PEL; 7 (15%) had ≥1 exposure between the AL and PEL. Thirty‐four (72%) workplaces were cited for ≥1 RCS standard violation. Twenty‐seven (57%) workplaces were cited for ≥1 respiratory protection standard violation. Conclusions Our investigation demonstrates widespread RCS overexposure among workers and numerous employer Cal/OSHA standard violation citations. More enforcement and educational efforts could improve employer compliance with Cal/OSHA standards and inform employers and employees of the risks for RCS exposure and strategies for reducing exposure.

Silicosis Among Immigrant Engineered Stone (Quartz) Countertop Fabrication Workers in California

“…The mainstay of managing patients with silicosis is minimizing further exposure. This can be challenging, as inadequate dust suppression and poor compliance with respiratory protection regulations are common in this industry . The NIOSH hierarchy of controls for worker safety prioritizes the elimination of hazardous exposure, followed by use of engineering controls; personal protective equipment is least effective .…”

“…Manufacturers deliver slabs to shops where fabricators cut, sand, and polish the material and generate levels of crystalline silica dust that may be hazardous. Fabrication is frequently performed in shops where ventilation, dust control methods, and personal protective equipment are inadequate …”

“…Despite a comprehensive Occupational Safety and Health Administration standard for exposure to silica dust, there are concerns about exposure and disease burden among people who work with engineered stone. During workplace inspections by California’s Division of Occupational Safety and Health, air sampling found levels above the permissible exposure limit of 50 µg/m 3 among 25% of employees and 51% of workplaces . Water suppression can reduce crystalline silica dust exposure by 10-fold but is often insufficient to reduce exposure below the permissible exposure limit without local exhaust ventilation and appropriate personal protective equipment .…”

Self‐reported silica exposures and workplace protections among engineered stone fabrication workers in California

“…While these findings are based on worker report, they are consistent with our prior review of Cal/OSHA citations issued as a result of this SEP, which found that 72% of employers were cited for violations of the silica standard. 4 Our study had several limitations. Findings were based on worker self-report; workers may have limited recall of past work practices and may also have been hesitant to report perceived workplace safety issues to Cal/OSHA inspectors.…”

“…We have previously reported high prevalence of silicosis among workers in this industry, and our prior analysis of inspection data from a California Division of Occupational Safety and Health (Cal/OSHA) silica Special Emphasis Program (SEP) found widespread silica overexposure and Cal/OSHA regulation violations at California stone fabrication workplaces. [2][3][4] As part of the SEP, Cal/OSHA also conducted worker interviews, the results of which have not previously been reported. Prompted by Tustin et al's findings and our prior work, we analyzed data from these interviews to evaluate worker-reported silica exposures and workplace protections, including utilization of medical surveillance, in engineered stone fabrication workplaces in California.…”