“…The program controls the interview logic, branching to or skipping questions as needed according to the responses of the interviewee, and it validates the logic of the data as they are entered. The exposure part of the questionnaire was designed specifically for this study, while the part on respiratory symptoms and diseases was modified from the questionnaire used in the Finnish Environment and Asthma Study that was originally designed for studying general population samples (8,(21)(22)(23). The questionnaire inquired about personal characteristics, occupational history, use of chemicals and other agents, job tasks, preventive measures, smoking, and the occurrence of upper and lower respiratory symptoms, asthma, skin symptoms, and some general symptoms.…”