There are few reports on peripheral air way due to chromate hazard, although many reports about upper and large respiratory tract disturbance were present. In this report, the bronchiolar and alveolar injuries due to chromate compounds were examined based on clinical, pathological investigation and animal experiments. The results were as follows. (1) Clinical investigations of former chromate workers (93 subjects): (a) Based upon findings of lung function tests and chest radiographs, no cases were diagnosed as definite emphysema, and there were only 4 suspected cases of emphysema. (b) 93 subjects were divided to 8 groups by smoking history and labor period, and were examined for their lung function. The values of %FVC, FEV1.0%, V50, V25, MMEFR, CV/VC% and delta N2% of these groups revealed within normal limits. (2) Pathological examination of autopsied and resected lung of 9 chromate lung cancer patients showed emphysematous changes of 8 cases, of which severe grade of emphysematous changes seen in only one, and mild or moderate emphysematous changes in seven. (3) All of the animals treated with monochromate or sodium dichromate, both of which were hexavalent chromate, showed emphysema in the long term experiments, but none treated with chromite ore (trivalent chromate) or saline. (4) The animals showed congestion soon after injection of monochromate in the short term experiments. Emphysematous changes clearly observed in 2 days. Based on our animal experiments, it is concluded that hexavalent chromate acts as a cause to produce emphysema. But clinically it seems reasonable to conclude that effects of chromate compounds to induce emphysema are very mild in men.