Reaction of the airways to inhaled Berodual was evaluated in two groups of metallurgists surveilled by systematic, complex medical examinations for appx. 25 years: 31 coke oven and 31 cold-rolling mill workers. All subjects under examination were active smokers, smoking more than 20 cigarettes a day. The frequency of ventilatory disorders: central bronchi obturation, small bronchi obturation and emphysemal changes, as well as microclimatic conditions of their living places, even mean anthropometric indices were similar. The main differentiating factor was presence of air pollutants in their workshops. Employees of coke owen division were exposed to variety of noxious substances: CO, NO_x, SO₂, benzene, its derivatives, HCN and policyclic aromatic hydrocarbons. In cold rolling division concentration of air pollutions was much smaller and virtually devoided of BaP. As revealed by Berodual provocation test in coke owen workers irreversible obturation and fixed emphysemal changes were far more frequent than in workers of cold rolling mill performing their job in favorable microclimatic conditions.