In a mill spinning coarse cotton the prevalence of byssinosis and other respiratory symptoms, and the F.E.V.1·0, were measured in a group of 29 men and 117 women employed in the winding room. All the men and 95% of the women at risk were included.
Dust concentrations, measured with a modified Hexhlet at various work points in the winding room, ranged from 1·65 to 6·05 mg./m.3 total dust. These concentrations are higher than 1·0 mg./m.3, which is the threshold limit value for cotton dust recommended by the American Conference of Governmental Industrial Hygienists. The mean dust concentration was 3·48 mg./m.3 compared with 2·85 mg./m.3 in the card room of the same mill.
The prevalence of byssinosis was 18·8% among the women and 13·8% among the men. A comparison among the women showed that those with symptoms of byssinosis had, on the average, significantly lower F.E.V.s than women of similar age without such symptoms. Four women and one man with moderately severe symptoms of byssinosis showed evidence of permanent respiratory disability with effort intolerance and a substantial diminution in F.E.V.1·0. Further studies should be carried out in other winding rooms because, if these findings are repeated elsewhere, they would indicate the necessity for medical surveillance, dust control, and extending the compensation scheme to include winding room workers.