Abstract
OBJECTIVES: This longitudinal study examines the severity of worker exposure to respirable crystalline silica (RCS) and respirable dust and demonstrates the need for increased education and implementation of both appropriate engineering controls and respiratory protection (RP) programs for stone fabricator shops, given the growing global number of accelerated silicosis cases associated with the fabrication of engineered stone (ES) countertops. METHODS: Personal air sampling results and detailed job description notes obtained from 17 industrial hygiene air sampling visits conducted at 11 stone fabrication facilities between 2017 and 2023 in Georgia were used to align similar exposure groups (SEGs) for tasks for workers performing stone fabrication. Bayesian decision analysis was used to determine appropriate RP selection recommendations for the 4 proposed SEGs: SEG1-Support, SEG2-Automated Tool Operator, SEG 3-Small Tool Operator, and SEG 4-Fabrication/Lamination. RESULTS: The analysis concluded that all employees in stone fabrication shops that process ES should wear a respirator with a minimum assigned protection factor (APF) of 10, regardless of the engineering controls in place. For SEG 4, it is recommended that workers use respirators with an APF between 50 and 1,000. Among the 75 full-shift personal air samples for RCS dust, 41 samples (53%) exceeded the permissible exposure limit of 50 µg/m³. CONCLUSIONS: This is the first study to present the 4 SEG categories with sampling data to support the importance of including all employees (even support workers) in RP programs, exposure monitoring, and medical surveillance. RECOMMENDATION AND IMPLICATIONS: Employers, occupational health professionals, and inspectors may use these SEG categories and corresponding RP recommendations to determine if employees have received appropriate RP for workers at stone countertop fabrication shops.