Cananea copper mine: An international effort to improve hazardous working conditions in Mexico.

A team of international occupational health and safety professionals evaluated the working conditions and health status of miners at a giant open-pit copper mine in Cananea, Mexico. Workers in the ore processing plants were exposed to levels of crystalline silica 10 times the Mexican regulatory limit, high levels of acid mist and noise, and numerous safety hazards, including unguarded machinery and malfunctioning 10- and 15-ton cranes. Lung function testing and interviews with physicians showed a substantial percentage of miners with adverse respiratory symptoms including shortness of breath (46%), wheezing (12%), coughing (12%), and elevated sputum production (10%). The mine owner, Grupo Mexico, violated Mexican law by failing to conduct an industrial hygiene survey sufficient to identify, evaluate, and control health hazards including exposure to mineral dust (including silica), acid mists, airborne solvents, high noise levels, high vibration levels, and extreme temperatures.