Lung cancer risk associated with manufacture of asbestos-cement products.

The mortality experience of a cohort of 5645 Louisiana asbestos-cement workers with a minimum follow-up of 20 years was related to total dust, duration and concentration of exposure and fibre type. Excess respiratory cancer risk was detected in workers with moderate and heavy asbestos dust exposure, but no excess risk occurred in categories of lower exposure. Mortality due to all other causes was normal. Both duration and level of exposure were shown to contribute to risk; both variables exhibited levels at which no excess mortality was detected. Workers exposed to both chrysotile and crocidolite appeared to be at greater risk of respiratory malignancy than those with exposure to chrysotile only.