3.10 Lung disease, smoking and occupational exposures

In 1985 the US Surgeon General concluded that 'for the majority of American workers who smoke, cigarette smoke represents a greater cause of death and disability than their workplace environment.' Additionally, some workers are exposed to other hazardous agents in the course of their work, which may react synergistically with tobacco to increase the risk of disease.

A well documented example is the interaction of asbestos exposure and cigarette smoke. Among the non-asbestos-exposed population, smoking increases the lung cancer rate approximately tenfold. In non-smoking asbestos workers, the lung cancer rate is increased fivefold. But among asbestos workers who smoke, the lung cancer rate is increased fiftyfold. In other words, for those workers who both smoke and are exposed to asbestos, the risk of developing and dying from lung cancer is 50 times greater than the risk for individuals who neither smoke nor are exposed to asbestos at work. The risk is also dose-responsive, varying with exposure to both contributing factors. Heavy smokers heavily exposed to asbestos will have a higher than fiftyfold increase.

Combined with cigarette smoking, exposures to coal dust, grain, silica, cotton dust, the welding environment, sulphur dioxide and cement dust cause a higher incidence of chronic bronchitis. Cigarette smoking linked with coal dust exposure generates a higher incidence of respiratory disease. There is also ample evidence suggesting that exposures to petrochemicals, aromatic amines and pesticides interact with tobacco smoke. Exposure to ionizing radiation in addition to cigarette smoke interacts to produce lung cancer. British evidence suggests that smokers may be more vulnerable than non-smokers to the harmful effects of uranium.(130)

It has been estimated that 793 lung cancer (including pleural and other respiratory cancer) deaths occurred in 1988 in Australia due to occupational exposures. Of these, 715 occurred in men and 78 in women. This number represents around 13% of total lung cancer deaths for that year. The authors note that this is likely to be an underestimate.(131)