[Disorders of the respiratory tract in workers in the chemical industry]. 
This paper studies the prevalence of chronic respiratory symptoms and diseases in 567 chemical workers and in 340 controls as well as their ventilatory capacity.  The prevalence of all chronic respiratory symptoms was found to be significantly higher in the exposed workers than in controls (p < 0.01).  Workers aged over 40 and those employed for over 10 years demonstrated higher prevalence of chronic respiratory symptoms than the workers up to 40 and those employed for up to 10 years, although the differences were not statistically significant.  A large number of chemical workers complained of acute respiratory symptoms manifesting during the shift.  The measured values of ventilatory capacity in chemical workers were significantly lower than those predicted.  The findings were more pronounced in workers over 40 and in those employed for over 10 years.  The measured values of gases and fumes in the working environment were mostly below the recommended values.  Our data suggest that, in spite of low atmospheric pollution of the working environment, sensitive workers may develop respiratory impairments.