Assessment of Silica Dust Hazards in Small-Scale Granite Quarrying Operations in Ogun State, South West Nigeria

Silica dust generated during granite quarrying is a leading cause of occupational lung disease globally, and its hazard profile in small-scale quarrying in Nigeria has been insufficiently characterised. This study assesses silica dust hazard levels and worker exposure risk in small-scale granite quarrying operations in Sagamu Local Government Area, Ogun State, South West Nigeria. Respirable dust samples were collected using personal sampling pumps worn by workers across drilling, blasting, crushing, and screening operations over three working days. Samples were analysed for respirable crystalline silica content using Fourier transform infrared spectroscopy. Worker exposure data were compared against the American Conference of Governmental Industrial Hygienists threshold limit value for crystalline quartz of 0.025 milligrams per cubic metre. Results reveal that 81 percent of drillers and 64 percent of crusher operators exceeded the silica exposure threshold during monitored shifts. Few workers wore appropriate respiratory protective equipment, and those who did rarely achieved a proper face seal. The study documents a near-total absence of pre-employment and periodic medical surveillance for silicosis among the workforce. Urgent recommendations include introduction of wet drilling techniques, provision of NIOSH-approved respirators, and mandatory chest X-ray screening programmes. These findings address a critical evidence gap in occupational silica exposure documentation for Nigerian quarrying operations. Keywords: silica dust, granite quarrying, Ogun State, silicosis, occupational exposure.