Workers' exposure during oil drilling is complex. Oil drilling fluids consist of mineral oils and additives. During drilling the fluids are exposed to high temperatures and pressure, and chemicals may decompose. An oil driller may be exposed to the origin al drilling fluid, potential decomposition products, particles originating from the rocks and oil/gas. Airborne oil mist and oil vapour have been determined for surveillance of the workers.
Few scientific reports are dealing with lung diseases in huma ns exposed to oil mist/oil vapour in oil drilling or in general. The few available animal studies suggest that high exposure to mineral oil based oil mist may cause pathological alterations of the lung alveoli, while the bronchii appear to be less vulnera ble. Humans exposed to mineral oils had signs of restrictive lung function impairment, while cable workers had higher prevalence of lung fibrosis. Oil mist exposure may have an impact on the lung alveoli and results in restrictive functional lung impairme nt and lung fibrosis.
This proposed study consists of two parts. 64 currently exposed oil drillers and the same number of non-exposed referents are examined before leaving offshore after an exposure free interval of three weeks and reexamined when they return 14 days later in a cross shift study. Personal exposure to oil mist/oil vapour, lung function emphasizing gas diffusion capacity, biomarkers indicative of epithelial lung injury and systemic inflammation are examined with the aim to assess the pos sibility of the exposed subjects having health effects related to ongoing exposure. In the second part of the study 50 previously exposed workers are examined with high resolution computer tomography of the lungs to assess fibrosis. The target group of th is cross sectional study consist of all subjects who were oil drillers on January 1, 1985 with at least 3 years of exposure.They have been much higher exposed than the current drillers.