"The Survey consisted of five parts: the environmental examination of the workplace, record of subjective symptoms, physical examinations, and the functional tests of the workers as well as laboratory examinations of the worker's blood.
As the subjects of the survey, 1,074 male workers of a factory were selected, and 341 workers in that group were excluded because their definite disease. The remaining 733 workers were divided into three groups of A, B and C according to the difference of environment and work. Group A consisted of the workers exposed to carbon monoxide. This group was further divided into subgroups A1 ancl A2.
The factory, of which workers were subjected to the survey was producing nitrolime and carborundum. In the both processes of the nitrolime and carborundum production, raw materials were burned with coal in electric furnaces. During all the electric furnaces were in operation, not less amount of CO as well as carbon dioxide escaped from the furnaces, and was staining the air of the work places. Of course the furnaces radiated great amounts of heat.
The CO concentration in the air was estimated by the iodine pentoxide method. The palladium chloride papers were also used for roughly estimating the CO content in the air. The carbon dioxide concentration of the air was estimated by barium hydroxide. Otherwise, temperature, radiation temperature, humidity, barometric pressure, and air motion in the workplace were also recorded.
The workers were charged to fill up a card which contained 18 items concerning common and possible complaints of CO poisoning. Occupational history, past history and family history were also taken by physicians. The items described in the card by each worker were ascertained by a physician on each worker by means of an interview. The data obtained were classified by the kind of job for analysis of the complaints.
Physical examination for Signs including percussion, auscultation and teleroentgenogram of the chest were practiced for all the workers.
As functional tests, vital capacity and strength of back were examined for all the workers.
For a part of the workers in each group, the estimation of CO hemoglobin (carboxyhemoglobin = COHb saturation) was carried out. The blood specimen for this estimation was collected at 20-30 minutes after the end of the job. During this time, smoking was refrained from for the workers. CO hemoglobin was measured with the pyrotannic acid method."
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