This is a result of clinical examination for workers working with Chromic acid and Chromium compounds in the plating room of their companies. I selected two companies that the plating process and the kinds of plating were similar. One (SW Co.) was more or less improved the operating environment with the ventilation machine so on and another (SR Co.) did not it so. The former was examined at March 29th 1977, the latter was at June 28th 1976. But the respiratory communicable diseases, flue or common cold so on were not spreaded there at that time. The clinical aspects were compared between the group of SW, and SR. The swelling and hyperemic signs of nasal mucous membrane and the experience of nasal bleeding were about 50%, generally, in all the groups. The following problem was dizziness or vertigo. The nasal signs in the group of SW (improved ventilation of the room air) were relatively weak, but in another, it was some what severe; - there was necrotic sign with thick nasal clast. They were only used of gauze mask when the vapors of various solvents were deeply full in the room. And there was very high rate of bronchial signs, sputum or coughing in the group of SW improved ventilation so called, than another one. I suppose that it means chronic inflammatory change of the bronchial mucous membrane with deeper signs, due to the individual protectors were carelessly or not used according to the improving of the operating environment. Theses nasal signs mentioned the above were not nearly in the other groups had not been done the Chromium plating. The Status of RBC, Hb and Ht, of urine protein and urobilinogen were mostly in normal range. But the number of WBC was more or less showed with a positive correlation to the working duration.