Operatives without byssinosis who complained of work related wheeze had a lower PPFEVI and PPFVC than those without this symptom. Some of these people volunteered the fact that they had asthma and that the work environment made the wheeze worse. It is possible that a proportion of these people were workers with pre-existing asthma that tended to be exacerbated at work. A proportion, however, had become wheezy as a consequence of their work with cotton and the significance of this remains obscure as these people seemed not to have had byssinotic symptoms. A possibility is that some people become sensitised to a particular agent at work and have developed a form of occupational asthma discrete from the condition byssinosis. One of the long term purposes of this study is to consider this issue.