A respiratory questionnaire was administered to 4656 textile workers employed in 31 textile factories involved in spinning or weaving manmade fibre or cotton. In addition, levels of airborne dust and bacteria were measured in workzones and personal breathing zones. In all 182 people described symptoms of byssinosis. This represents a significant decline in the prevalence of byssinosis over the last ten years.

The prevalence of byssinosis was statistically significantly related to years worked in the industry, ethnic origin, dust exposure, workroom of employment, quality of cotton and smoking habit.

The correlation between the presence of byssinosis and the concentration of total dust less 'fly' measured in people's personal breathing zone was highly significant (r=0.92, p < 0.0001). The regression line suggests that at a concentration of <1.2mgm/M³, less than 5% of people are at risk of developing byssinosis.