Probabilistic health risk assessment of respirable dust exposure among stone carvers in Thailand using average daily dose and Monte Carlo simulation.

Respirable dust (RD) exposure represents a significant occupational health concern in stone processing settings, particularly among stone carvers who are at elevated risk due to high levels of dust generation. Prolonged exposure to RD is associated with serious adverse health outcomes, including lung cancer. This study aimed to evaluate the probabilistic risk associated with RD exposure using Monte Carlo simulation and to estimate the Incremental Lifetime Cancer Risk (ILCR) among stone carvers. A cross-sectional study was conducted across five occupational categories: mining, cutting, splitting, knocking, and stone carving. Personal air sampling was performed in accordance with the NIOSH 7601 method to determine time-weighted average (TWA) RD concentrations. ILCR was estimated using Monte Carlo simulation with 10,000 iterations, incorporating exposure parameters and health risk assessment models based on U.S. EPA guidelines. The mean RD concentrations did not exceed either the Thai occupational exposure limit (OEL) or the threshold limit value (TLV) in any of the five occupational categories, with the highest level observed among stone carvers (0.051 mg/m3). Although ILCR values for all groups were within the acceptable threshold of 1.00 × 10 -6, the highest mean ILCR was identified in the stone carving group (3.325 × 10 -7). These findings suggest that, despite being within acceptable limits, workers may still face potential health risks from RD exposure. The results underscore the need for strengthened regulatory enforcement and comprehensive control strategies, including engineering controls, respiratory protection, and targeted health education, to mitigate exposure and prevent silica-related diseases in this high-risk population.