Informal welders' occupational safety and environmental health risks in northwestern Tanzania

Often with minimal formal training and protections, informal welders face significant occupational health and safety (OSH) risks. This cross-sectional study of 219 adult informal welders at 70 informal welding sites in Mwanza City, Tanzania aimed to: 1) capture knowledge and awareness of occupational risks and safety precautions, training, and self-reported work-related injuries and illness and 2) observe worker use of personal protective equipment and site safety. We hypothesized that knowledge, awareness, and site inspections would improve use of PPE and that improved safety and site inspections would reduce self-reported injuries and illness. A generalized linear model (GLM) was used to model all relationships. Robust standard error estimation was used to avoid overestimation of parameters. Having a post-secondary education (aβ = 1.01, 95% CI: 0.962, 1.061; p = 0. 0679), having training in OSH (aβ = 0.927, 95% CI: 0.872, 0.984, p = 0.014), increased knowledge of occupational risks (aβ = 1.305, 95% CI: 1.143, 1.491; p<0.001), and knowledge of safety measures (aβ = 1.112, 95% CI: 0.881, 1.404; p = 0.372) increased PPE use by 1%, 7.3%, 30.5%, and 11.2% respectively. Workers who used PPE were less likely to experience fire explosions (AOR = 0.149, 95% CI: 0.029, 0.751; p = 0.02), radiation exposure (AOR = 0.097, 95% CI: 0.016, 0.579, p = 0.01) or electric shocks (AOR = 0.012; 95% CI: 0.001, 0.11, p<0.001). Having increased knowledge of safety practices also decreased the odds of fire explosions (AOR = 0.075, 95% CI: 0.018, 0.314; p<0.001). Those with higher knowledge of occupational risk (aβ = 1.57, 95% CI: 1.404, 1.756; p<0.001) and safety measures (aβ = 1.628, 95% CI: 1.34, 1.978; p<0.001) were more likely to have more positive attitudes towards safety practices. Our findings suggest that comprehensive targeted interventions including increased knowledge of occupational risks, safety practices, and occupational health law through training, along with enforcement and inspection by government officials, would benefit the environmental and occupational health for informal welders.