The author wishes to emphasize the following: During the 10 month period of investigation, all deaths occurring in this plant were due to carcinoma of the lung. Taking into consideration that an annual turnover of 40 to 50 per cent influences computation of the number of employees, I found the total number did not range more than 600. Since, of the series of seven cases, one died beyond the annual period, the incidence of carcinoma was at least one in 600 employees. In the same state of two million population, the death rate from primary lung cancer averages 10 cases (men and women inclusive) per 100,000 annually. In comparable figures, the death rate in the plant would constitute 166 in 100,000 or an incidence at least 166 times greater than found in the rest of the population. This figure positively eliminates consideration of any mathematical or problematical error. All in all, the evidence in the past and by the present author is much too emphatic to allow any view other than chromates are definitely cancerigenic: susceptible individuals, exposed to atmospheric concentrations of more than 1 mg. per cubic meter of air, for a duration of an average of seven years—perhaps less—are subject to develop bronchogenic carcinoma.