AN OUTBREAK OF THE CASES OF NITROGLYCOL POISONING IN JAPAN

Abstract

In Japan it was about 1955 when partial substitution of nitroglycol was initiated for nitroglycerine as a staple ingredient of dynamite, and in 1960 the mixing rate rose up to 60%. In the summer of 1960 six fatal cases from nitroglycol poisoning in two dynamite factories were reported and roused keen social concern. At that time the concentration of nitroglycol in the air of cartridge-making, wrapping, or packing rooms was often above 0.5 ppm. But at present the concentration has been notably decreased through such means as improvement of exhaust ventilation, suppression of the elevation of material temperature, and especially keeping the mixing rate of nitroglycol below 30%. At present there are almost no working room where the concentration of nitroglycol is above 0.25 ppm, which is MAC in the air as adviced desirable by the Ministry of Labor for the control of nitroglycol poisoning in December 1960 and in May 1961. However, it still remains as a problem that protection of the skin of the workers in the above stated working rooms is not yet satisfactory. On the other hand, many clinical as well as experimental investigations have been made in order to provide adequate curative as well as preventive measures for nitroglycol workers. Some of them are attacked with characteristic paroxysms simulating angina pectoris often on holidays or on its next days. Although the pathologic mechanism is not yet clear, we have found ischemic changes in the patient's hearts by necropsy and in the heart muscle of rabbits experiment. At present, it is impossible exactly to predict and to prevent these paroxysms. But, on account of the fact that such paroxysms occur among workers employed for a long time, we think it is advisable to transfer to other jobs those workers with one or more clinically abnormal findings by continuous observation on long-time workers. As clinical abnormal findings in this case the Ministry of Labor is suggesting such items as fits simulating angina pectoris, chest pain, digestive disorder, headache, etc., i.e. subjective symptoms, as well as abnormality in the specific gravity of the whole blood, blood pressure, electrocardiogram, and liver functions, i.e. abnormal results by clinical tests and observations. We are suspecting further those who show abnormality by the cold pressor test, increase of fatty acids in the blood, relative increase of globulin against albumin in the blood, i.e. decrease of the ratio albumin/globulin, anesthesia of fingers, and central scotoma. (The above is a summary of the knowledge as advanced by the Committee for the Control of Nitroglycol Poisoning established in Japan Industrial Explosive Association in the autumn of 1960.)