Oil mists are aerosols of cutting fluids comprising straight oils or aqueous fluids (soluble oils or synthetic fluids). Certain chemicals can be present in such fluids or can form while they are being used: in particular polycyclic aromatic hydrocarbons (PAHs) (straight oils and soluble fluids), and nitrosamines (aqueous fluids).
The concentration of these pollutants has changed over time due to improvements made in the composition and in the nature of the cutting fluids. Past epidemiological studies have suggested that bladder cancers are more frequent in populations that use cutting oils which are unrefined or relatively unrefined. However, studies per type of fluid show discordant results.
The objective of this study by INRS was to determine whether a risk of bladder cancer is associated with occupational exposure to oil mist, resulting from the more recent use of straight oils or aqueous fluids, while taking into account other occupational and extra-occupational carcinogens. This risk was studied in the steel industry in the Nord-Pas de Calais Region in France.
A case-control study was put in place in a cohort constituted of all employees recruited from 1960 to 1997 in 6 steel works in the Nord–Pas-de-Calais Region. The cases of bladder cancers occurring in the subjects of the cohort, during the period 2006-2012, were identified based on data from the French National Health Insurance scheme, and on information from 21 public and private hospitals in the Nord-Pas-de-Calais Region.
This study showed a relationship between occurrence of bladder cancer and occupational exposures to cutting fluid mists of all types, as well as straight-oil cutting fluid mists. The relationship observed for straight-oil cutting fluids dates back to exposures of 30 years ago. This study did not show any relationship between bladder cancer and exposures to aqueous fluids (soluble oils or synthetic fluids).
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