Respiratory function and disease among workers in alkaline dusts.

Little is known of the possible effects of sodium carbonate dust on the lower respiratory passages. A large alkali industry, with a number of works, was used for an investigation of lime and soda ash dusts evolved during the process. The physical and chemical characteristics of these dusts and details of the type of work and environmental conditions are described. In 1954 and 1956 a survey was made of respiratory sickness absence, chest radiographic appearance, and respiratory function in workers employed in areas with exposure to soda ash, lime dust, and no dust. All were interrogated about their smoking habits. In 1954 there was found to be a significant reduction in expiratory flow rate of workers in dusty jobs in soda ash compared with the group not exposed to dust but this result was nullified in a random sample group in 1955 and in full groups in 1956. Respiratory sickness absence was found to be slightly greater in workers in dusty occupations, particularly in lime dust. No pneumoconiosis was detected on miniature films. The survey of smoking habits revealed that smoking was associated with a definite decrease in the expiratory flow rate, particularly after the age of 40 in heavy smokers. It was concluded that smoking habits played a more important part than alkaline dusts in the reduction of respiratory efficiency as measured by a study of sickness absence and performance of a simple spirometric test.