An outbreak of work‐related asthma and silicosis at a US countertop manufacturing and fabrication facility

Abstract

Background: Outbreaks of severe silicosis have affected workers who fabricate artificial stone countertops. Work-related asthma (WRA) has not been a prominent feature of those prior outbreaks.Methods: This report describes an outbreak of WRA and silicosis at a facility that manufactures and fabricates chemical-resistant countertops comprised of sand, epoxy resin, and phthalic anhydride (PA), a known respiratory sensitizer. The multidisciplinary investigation included clinical examinations of workers, an industrial hygiene survey with qualitative and quantitative exposure assessments, and a crosssectional questionnaire.Results: Engineering controls and personal protective equipment were inadequate. Some workers were exposed to PA or silica above permissible exposure limits established by the Occupational Safety and Health Administration (OSHA). Clinical and epidemiologic investigations identified 16 workers with confirmed or suspected WRA. Two years later, after OSHA began to enforce its new silica standards, 12 workers received medical surveillance for silicosis. Of these 12 workers, four (33.3%) were diagnosed with silicosis based on abnormal chest computed tomography examinations.Conclusions: Artificial stone countertop workers can develop asthma or silicosis.Risk of asthma may be highest in workers exposed to asthmagens such as PA and epoxy resins while manufacturing the artificial stone material.

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

“…Findings that 25% of sampled employees had RCS exposures above PEL are similar to results of nationwide OSHA sampling (29% [82/282 personal air samples]) of industries where engineered stone countertop manufacturing may have taken place during the first year that the new standard was enforced (2017-2018). 7 Our data add to published reports of RCS exposures in stone fabrication workers. Salamon et al collected a full-shift personal air sample from 51 employees at four workplaces in Italy and reported exposures ranging from <3 to 98 μg/m 3 , 13.7% of which were above OSHA PEL.…”

“…Approximately half of the workplaces where personal air sampling was performed had at least one employee with RCS exposure above PEL, the highest of which was 13 times greater than PEL. Findings that 25% of sampled employees had RCS exposures above PEL are similar to results of nationwide OSHA sampling (29% [82/282 personal air samples]) of industries where engineered stone countertop manufacturing may have taken place during the first year that the new standard was enforced (2017–2018) 7 …”

“…Stone fabrication is the process of cutting and polishing stone, typically for use as countertops. Since 2010, reports from several countries, including the United States, have shown that workers involved in the fabrication of engineered stone, also known as artificial stone or quartz agglomerate, are at high risk for exposure to RCS and the subsequent development of silicosis 4–7 . Silicosis screening in California and Australia has identified disease prevalence of 12%–21% among workers in this industry 4,8,9 …”

“…Since 2010, reports from several countries, including the United States, have shown that workers involved in the fabrication of engineered stone, also known as artificial stone or quartz agglomerate, are at high risk for exposure to RCS and the subsequent development of silicosis. [4][5][6][7] Silicosis screening in California and Australia has identified disease prevalence of 12%-21% among workers in this industry. 4,8,9 Of particular concern in this industry has been the higher incidence of accelerated silicosis, a more rapidly progressive form of the disease, particularly in younger workers.…”

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

“…Self-reported silica exposures and workplace protections among engineered stone fabrication workers in California Tustin et al described cases of silicosis among workers at a US workplace that manufactures and fabricates engineered stone (also known as artificial stone or quartz conglomerate) countertops. 1 These cases were identified through Occupational Safety and Health Administration (OSHA)-mandated medical surveillance, after an investigation found that workers at this plant were exposed to respirable crystalline silica above the OSHA permissible exposure limit (PEL). 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.…”