Diem, L., and Weill, H. (1977). Thorax, 32,[281][282][283][284][285][286]. Respiratory health and dust levels in cottonseed mills. Four cottonseed mills in the southern United States contained high levels of total and respirable dust. A survey of 172 workers showed low prevalences of byssinosis (2-3%) and chronic bronchitis (4%). Mean baseline (out of dust) lung function values were normal. Mean functional declines over the working shift were present on Monday and absent on Friday, indicating an acute bronchoconstrictor response. Despite limitations in translating measured dust levels into estimates of individual exposures, the overall dose-response relationship seems to differ from that found in the cotton textile industry.Byssinosis may result from inhaling any of several vegetable fibres under a variety of occupational exposures. The cotton textile industry has been the locus of most of the systematic studies of the disease. Non-textile exposures to cotton dust have received little attention, probably because these operations are predominantly rural, dispersed, and seasonal, and have a high turnover of unskilled labour.As a result of the morbidity and disability from byssinosis in textile workers, governments have undertaken to regulate the permissible exposure to cotton dust. The major task is to define a safe and feasible limit of exposure. It is reasonable also to consider whether to apply the same standard to all sources of airborne cotton dust. The answer to this question should depend upon whether byssinosis is found in non-textile workers, and whether the dust-dose biologic-response relationship is similar to that in the textile industry.Cottonseed is an important product of cotton cultivation. Seed mills separate the raw cottonseed into 'linters' (attached short cotton fibres), hulls, and meats, the last being the source of oil and cake or meal. The early steps in processing involve removal of coarse trash by mechanical shakers, stripping the linters from hulls by revolving saws, and collecting the baling linters. These operations raise substantial amounts of dust. The cottonseed is not treated in any way before it reaches the mill.
Study population and methodsIn the summer of 1975, we studied workers in four cottonseed mills in the southern United States. We attempted to recruit all workers in dusty jobs and a number of other cottonseed mill workers (thought to be only minimally exposed to dust) to serve as a comparison group. In three mills, we recruited as many workers as were willing to participate. In the fourth and largest mill, all workers in dusty jobs were recruited, and as many with minimal exposures as study time permitted. One hundred and seventy-two workers completed the interview; 153 completed function studies for inclusion in the Monday analysis (reasons for exclusion included having less than 40 hours off work before testing, or unexpected absence from work). Of these 153 workers, 145 were available for study on Friday of the same week.Frequency distributions of the ages and length o...