Yusho disease: Kanemi rice oil contaminated with PCB, Japan

A world famous case. In 1968 "Kanemi rice oil" was contaminated with PCB, which was used for heating and circulated through a coil. Somehow, cracks in the coil appeared and PCBs leaked out, contaminating the cooking oil. There were over 14,000 victims.


This was a crucial case not only for Japan but for the world in the battle to prove the risks from PCBs. From February to March, 1968, a mysterious sickness causing difficulty in breathing occurred in poultry farms in a wide area of western Japan, resulting in the death of over 400 thousand birds. These chickens had been fed the dark oil produced at Kanemi Co. The Yushō disease (油症?) was a mass poisoning by polychlorinated biphenyls (PCBs). For deodorization, the oil was heated using PCB as the heating medium, circulating through pipes. Due to holes in the pipes the PCB leaked into the rice bran oil.

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Basic Data
NameYusho disease: Kanemi rice oil contaminated with PCB, Japan
ProvinceFukuoka Prefecture
SiteKitakyushu City
Accuracy of LocationMEDIUM regional level
Source of Conflict
Type of Conflict (1st level)Biomass and Land Conflicts (Forests, Agriculture, Fisheries and Livestock Management)
Type of Conflict (2nd level)Intensive food production (monoculture and livestock)
Chemical industries
Specific CommoditiesRice
Project Details and Actors
Project DetailsPCB is thought to have effects as an endocrine disruptor, in addition to causing direct health effects such as skin rush and many others. In Japan, PCB was noted for its toxicity with the Kanemi Yusho incident in 1968, as a turning point. Contaminated oil was sold in the marketplace and people who consumed it fell ill. Victims were afflicted with various health problems, such as skin pigmentation effects, an increased fetal death rate, and chlorine acne. Even before the harm to people was revealed, chickens had been affected. Hens were fed chicken feed contaminated with the oil and a massive death occurred; however, these deaths were not considered a serious issue. If they had been taken seriously, then perhaps the Kanemi Yusho accident would not have happened. The contaminating agent was Kanechlor 500 (KC-500), a brand name of PCBs.

The number of victims of the Kanemi Yusho incident exceeded 14,000. More than 30 years afterwards, yet victims were still suffering from their injuries. It turned out later that poly-chloro-dibenzofuran (PCDF), a dioxin, was also contained in the contaminated oils. Finally, in 2002, the Japanese Government admitted that the injuries were caused by PCBs, as well as dioxin. After the Kanemi Yusho Incident, people began to realize the toxicity of PCBs and the movements to forbid PCBs spread globally.

In 1974, the manufacture and the use of PCB were banned completely in Japan. Manufacture of PCB had started in 1929 at Swan Co., USA. Immediately after that, the toxicity of PCB began to cause problems such as the chlorine pimple disease in laborers, which was confirmed by animal experiments. However, because of the "excellent" properties of PCB, the production was expanded. The production of PCB in Japan was started in 1954. Soon after that, the pollution problems from PCB were found all over the world, such as contaminated feed for chickens also in the USA and environmental contamination in Sweden.
Type of PopulationUrban
Potential Affected Population14,000
Start Date1968
End Date2013
Relevant government actorsMinistry of Human Welfare

Ministry of Agriculture and Forestry

Courts of Law (district courts and Supreme Court)
Environmental justice organisations and other supportersGroups of plantiffs (Fukuoka group; Kokura group ...)

Kanemi Rice Bran Oil Poisoning Victims' Group
The Conflict and the Mobilization
Intensity of Conflict (at highest level)MEDIUM (street protests, visible mobilization)
When did the mobilization beginMobilization for reparations once impacts have been felt
Groups MobilizingLocal government/political parties
Local scientists/professionals
Support from leftist groups / political parties
Forms of MobilizationCommunity-based participative research (popular epidemiology studies, etc..)
Lawsuits, court cases, judicial activism
Official complaint letters and petitions
Public campaigns
Street protest/marches
Sitdowns in courts of justice
Health ImpactsVisible: Other Health impacts, Exposure to unknown or uncertain complex risks (radiation, etc…), Other environmental related diseases, Deaths
OtherMassive case of poisoning and persistent illnesses caused by contamination by PCB and dioxin. Endocrine disruptors. (See also "Other comments").
Socio-economic ImpactsVisible: Loss of livelihood, Violations of human rights
Potential: Increase in Corruption/Co-optation of different actors
Project StatusStopped
Pathways for conflict outcome / responseCompensation
Court decision (victory for environmental justice)
Court decision (undecided)
Development of AlternativesLiability of the Kanemi company was established. PCBs were banned some years after 1968.
Do you consider this as a success?Not Sure
Why? Explain briefly.Although there was some monetary compensation for the victims, this was very difficult to achieve and took a long time. Some court decisions were favourable and some not. The company survived the scandal and the damage done. PCBs were banned after some time.
Sources and Materials

Shigeto Tsuru, The Political Economy of the Environment: the case of Japan, 1999, p. 163-170 (on the Kanemi oil PCB case)

[1] European Environment Agency, Late lessons from early warnings 1896-2000, chapter 6, PCBs and the precautionary principle, by Janna G. Kappe and Jane Keys.
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Gensyu Umeda, PCB poisoning in Japan, Ambio 1(4)<. 132-134, Sept. 1972.
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Yoshito Masuda, The Yusho rice oil poisoning incident, chap. 19 in Arnold Schecter, ed. Dioxins and Health, Springer, 1994.
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The Yusho and Yucheng Rice Oil Poisoning Incidents, April 2012.

DOI: 10.1002/9781118184141.ch16. In Dioxins and Health including other Persistent Organic Pollutants and Endocrine Disruptors, Third Edition, John Wiley & Sons, Inc., by Yoshito Masuda and Arnold Schecter, pp.521-551.
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Japanese environmental pollution : a case study of the kanemi rice oil disease victims, by Phillip A. Hausknecht, Ann Arbor : Univ. MI, 1986.


Yusho disease, Wikipedia
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What are PCBs?
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Most Kanemi oil victims exempted from paybacks, The Japan Times, 2 June 2007
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The Japan Times, 22 March 2013: Suit in ’68 Kanemi oil poisoning axed. KITAKYUSHU – A branch of the Fukuoka District Court threw out a ¥605 million damages suit filed by victims of a massive food poisoning case in 1968 that was blamed on toxic cooking oil made by Kanemi Soko K.K.
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Hatamura Institute, Contamination of rice bran oil with PCB used as the heating medium by leakage through penetration holes at the heating coil tube in deodorization chamber.
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The Japan Times, Patients newly recognized as victims of a 1968 mass food poisoning across western Japan filed a ¥286 million damages suit against the manufacturer of the contaminated cooking oil, Kanemi Soko K.K., and two of its officials. May 24, 2008.
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Other Documents

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Other CommentsEEA, Late lessons from early warnings, ch. 6: " The Yusho accident. The first clinical sign was a strange skin disease with conjunctivitis, swelling of eyelids and

chloracne. The victims’ whole bodies, including the extremities, were covered with acne-like pustules. The most common symptoms were pigmentation of nails, skin and mucous membranes; increased sweating of the palms; severe headache; swollen joints and feelings of weakness. About half of the victims coughed persistently with expectoration resulting in a chronic bronchitis. These respiratory symptoms correlated with PCB levels in the blood. It took more than 10 years for these symptoms to decline. Some of the victims were pregnant when they

consumed the PCB-contaminated oil. Of 11 babies born to these mothers, two were stillborn. All were ‘Coca-Cola’ coloured, growth-retarded, had increased eye discharges and nail pigmentation. Follow-up studies of the children showed their

growth to be hampered, their IQs to be low, and their demeanour generally apathetic and dull. There was an increased mortality of the whole group of Yusho patients..." [1]
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Last update30/12/2016