Occupational Exposure to Respirable Crystalline Silica and Pulmonary Health Outcomes in Quarry Workers in Plateau State

Respirable crystalline silica (RCS) exposure remains a leading cause of preventable occupational lung disease globally, yet evidence from Nigeria's mining and quarrying sector is limited. This analytical cross-sectional study assessed RCS exposure levels and associated pulmonary health outcomes among quarry workers in Plateau State, North Central Nigeria. Two hundred and fifty quarry workers and 100 unexposed administrative staff as controls were recruited from three active quarry sites in Shendam and Pankshin local government areas. Personal RCS sampling was performed using cyclone samplers and polarized light microscopy. Spirometric lung function tests, chest radiographs interpreted using International Labour Organization classification, and respiratory symptom questionnaires were administered to all participants. Mean RCS concentration was 0.23 mg/m cubed, exceeding the 0.05 mg/m cubed occupational exposure limit in 79.2 percent of active work zones. Spirometric abnormalities were present in 58 percent of quarry workers versus 14 percent of controls. Radiographic evidence consistent with pneumoconiosis was identified in 23.2 percent of long-tenure workers. Silica exposure dose and cumulative work years were the strongest predictors of spirometric decline (p less than 0.001). This study provides new empirical data on silica-related pulmonary disease in Plateau State quarrying and recommends dust suppression controls, mandatory silica health surveillance, and enforcement of RCS exposure limits by the Plateau State Ministry of Mines and Steel Development. Keywords: silica exposure, pneumoconiosis, lung function, quarry workers, Plateau State.