Pneumoconiosis in iron ore surface mining in Labrador.

A cross-sectional survey of the work force at an iron ore surface mine and beneficiation plant in Labrador identified cases with a radiologic diagnosis compatible with simple pneumoconiosis by the International Labour Organization (ILO) classification (1980). Their distribution by ILO categories 1, 2, and 3, after excluding those with confounding diagnoses for pneumoconiosis, was 30, 10, and 2 cases, respectively. ILO category was related to age, duration of current employment, and cumulative respirable dust and quartz levels, as well as to decrement in ventilatory function.