Epidemiological studies on the Morinaga powdered milk poisoning incident (Japanese)

Abstract

In 1955, many babies who had drunk arsenic tainted milk produced at the Tokushima Plant suffered from serious poisoning. The number of victims ascertained in February, 1956 covering 27 prefectures in the western part of Japan was 12,159, of whom 131 died. The disaster was caused by the process of manufacturing the powdered milk. Disodium phosphate was added as a stabilizer to make the milk easily soluble. This disodium phosphate was poorly purified, intended for nonfood industrial use, and contained a toxic dose of arsenic, sodium arsenite and vanadium compounds etc. In 1969, the authors organized an epidemiological study group with Hiroshima and Okayama Universities and have developed joint research on this disaster. A follow up survey was made among victims in Okayama between December 1969 and April 1970. 214 people answered the questionnaire and 74 were given a medical examination. A prospective study was made on the basis of a questionnaire on clinical complaints collected at the time of the disaster in 1955. A comparative study was performed between the victims and their brothers and sisters. The results suggest that the victim children have a lower I.Q., a higher rate of severe retardation (below 50 I.Q.), a higher incidence of suffering from various ailments and of sick absenteeism from school, poorer school records and more emotional disturbances, a higher prevalence of myopia, too advanced to be corrected by glasses, more abnormal and borderline EEG findings, a higher DMF rate in their teeth, and higher rates of mortality, prevalence of abnormal ophthalmoscopic findings, retardation of physical growth during school age, retardation of skeletal growth including finger size, periodontal disease, prevalence of narrow range of vision and prevalence of abnormal X ray findings in teeth. The authors concluded that as a result of drinking arsenic tainted milk 17 years ago, many victims are still suffering from many physical and mental disorders which have brought social and economic difficulties to their families thus making the victims' own future uncertain.