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About Minamata

Minamata Mercury Satellite Symposium Committee
[6th International Conference on Mercury as a Global Pollutant (ICMGP) October 15th - 20th 2001, Minamata, Japan]

Minamata Disease
A History of Japanese Government andKumamoto Prefectural Irresponsibility

By Miyazawa Nobuo
Translated by Aileen Mioko Smith

October 15, 2001


Minamata Disease is one of the worst disasters in modern history. Now forty-five years since its discovery in May 1956, it is yet to be resolved.

This short chronology examines the policies and measures taken by the Japanese national and Kumamoto prefectural governments as they relate to Minamata Disease.

For the Japanese national government and Kumamoto prefecture -- the political powers concerning this disaster -- policies and countermeasures for Minamata Disease were not about comprehensive relief for victims. Rather, the forty-five year history of Minamata Disease has shown it to be completely the reverse.

To these political entities, policies and countermeasures concerning Minamata Disease were undertaken for the following purposes:

  • To enable and assure that production at Chisso's Minamata Factory [acetaldehyde plant] continue.
  • To ensure that the burden of compensation for Minamata Disease be kept to a minimum.

In one word, throughout the history of Minamata Disease, both the national and Kumamoto prefectural governments consistently stood on the side of the polluter which had caused the disaster.

As a result of initial efforts by the national and prefectural governments when the outbreak occurred, Minamata Disease was declared "concluded" in 1960.

Now again in 2001, this time in front of the entire international community, efforts are being undertaken to bring down the curtain on the Minamata Disease disaster forever. This is being done despite the fact the extent of the disaster and the resulting numbers of victims are unknown, and medical science concerning Minamata Disease as well as the responsible parties in the disaster being left ambiguous.

From The Beginning Countermeasures Were Neglected

Six months after the May 1, 1956 official discovery of Minamata Disease, the Kumamoto University Medical School investigation team on Minamata Disease made public that it strongly suspected the illness was caused by food poisoning from eating fish and shellfish from Minamata Bay and that the fish and shellfish were being contaminated by the waste water of the Chisso Minamata Factory. No measures were undertaken to stem the source of the problem.

On January 17, 1957, the Minamata Fishing Cooperative appealed to the Chisso factory to stop the factory's polluting waste water. On the 22nd of the same month, the cooperative appealed again, this time to the governor of Kumamoto Prefecture for him to take countermeasures concerning the waste water. In spite of these appeals, neither the factory nor the prefecture undertook any countermeasures.

At this point 54 victims had been medically identified as having the "Strange Disease" (Minamata Disease) of whom 17 had died.

By the spring of 1957, research conducted by both the Kumamoto University Medical School investigation team and the Ministry of Health and Welfare's investigation team had further strengthened suspicion that the Chisso Minamata Factory waste water was the cause of the poisoning.

Kumamoto Prefecture and the national government's Ministry of International Trade and Industry (MITI), however, in spite of the political power they could exert upon the Chisso corporation, undertook no countermeasure efforts. Neither did they order the company to investigate the problem. Kumamoto Prefecture went so far as to say that it was "operating on the premise that the factory waste water and the Strange Disease were unrelated."

Kumamoto Prefecture also did not undertake any measures to prevent the residents from eating the contaminated fish and shellfish. In the meantime the national government's Health and Welfare Ministry rejected the proposal to apply the Food Sanitation Act which would have forbidden the taking of Minamata Bay fish and shellfish for selling. Its reasoning, was that it was unknown whether all the fish and shellfish in Minamata Bay was poisoned. In this way, the national government neglected to prevent the disaster from spreading.

Waste water continued to be released into Minamata Bay by Chisso. With no official prohibition on fishing and no recourse for livelihood, the fisherfolk continued to make their living on fish.

From September 1958, Chisso diverted its acetaldehyde plant waste water, releasing it into the Shiranui Sea via its Hachiman [sedimentation] Pools at the Minamata River delta.

From April 1959, fisherfolk who fished in the Shiranui Sea fell ill with Minamata Disease. Many cats died in fishing villages along the shoreline of the Shiranui Sea, manifesting conditions of the "Strange Disease."

Still No Countermeasures Even After It Became Evident The Cause Was Organic Mercury

On July 22, 1959 the Kumamoto University Medical School investigation team reported that, based on the research it had conducted after examination of the Hunter-Russell (organic mercury poisoning) syndrome report, that the cause of Minamata Disease was a type of organic mercury compound. As a result, fisherfolk throughout the Shiranui Sea demanded the waste water be stopped and the plant's operations suspended.

Chisso and the Ministry of International Trade and Industry (MITI) exerted the full weight of their political power to undermine the Kumamoto University conclusions.

On November 12, 1959, the Ministry of Health and Welfare's Food Hygiene Investigation Committee acknowledged the validity of the findings of the Kumamoto University Medical School investigation team. The committee reported to the Health and Welfare minister that Minamata Disease was caused by the consumption of fish and shellfish from Minamata Bay, and was a food poisoning that attacks the central nervous system, the main cause being some type of organic mercury compound.

The following day the highest ranking government official concerning the Minamata Disease issue, MITI minister Ikeda Hayato declared, "It is too early to conclude that the cause [of Minamata Disease] is mercury." It is clear Minister Ikeda did not want to have Chisso's acetaldehyde plant production process to be connected causally to Minamata Disease.

Chisso, MITI, and Kumamoto Prefecture, kept the issue of responsibility for the disaster ambiguous and brought their political weight to bear to bring an end to the Minamata Disease incident.

MITI rushed through the installation of Chisso's "water purification equipment," the cyclator. (recycling system). Having put that in place, it deceived the public, declaring that public anxiety concerning Minamata Disease was now over.

Victims of Minamata Disease were told that Chisso was not responsible for their plight but, out of pity, a solatium would be paid. This was arranged through the governor of Kumamoto prefecture. The right to obtain this solatium would be limited to those who had been certified by a committee of medical doctors designated by the government. Only those that were certified by this committee would qualify.

In April of 1960, the national government, stating it would reinvestigate the cause of Minamata Disease from the start, established under the auspices of the Economic Planning Agency (EPA) the "Minamata Disease General Investigation and Research Liaison Council." The council's meetings were terminated one year later with no conclusions issued. The role this council played is evident. It was to make the cause of Minamata Disease remain ambiguous.

What Should Have Been Done After 1960

After the Ministry of Health and Welfare's Food Hygiene Investigation Committee report was issued in November of 1959, the government should have implemented measures to prevent the further spread of Minamata Disease and enacted measures for the relief of victims. Neither was done.

At this point both the Chisso Minamata Factory and MITI had knowledge of which facility of the Chisso factory (the acetaldehyde plant) was releasing the waste water containing mercury. The company and government should have therefore either stopped the waste water from being released, or found a way to eliminate the mercury from it. However, they did neither.

Instead, the public was told that the acetaldehyde waste water was being put through the "cyclator" purifying system. In reality, however, this was not done. Both Chisso and MITI knew the cyclator was incapable of capturing the mercury dissolved in the acetaldehyde waste water. The waste water containing the methyl mercury was instead mixed with sediments collected from the cyclator and sent to Chisso's Hachiman (sedimentation) Pools where, because the liquid contents of the pool were designed to leach out, it no doubt entered the Shiranui Sea.

Hair samples from residents living on the coastline of the Shiranui Sea were analyzed by the Kumamoto Prefecture Hygiene Research Institute. The laboratory measured mercury levels in the hair of 2700 individuals (up to 1962). The results showed that although mercury levels dropped around Minamata Bay itself, levels were on the increase around the Shiranui Sea as a whole. Kumamoto Prefecture neither researched this phenomenon to find out why it was happening, nor conducted any health investigation of the residents.

Nothing Was Done Even When The Causal Compound Was Identified

In February of 1963 it was made public that the causal element of Minamata Disease, methyl mercury chloride, was produced within the acetaldehyde manufacturing process. (The compound was extracted by Professor Irukayama Katsuro of Kumamoto University sometime around June of 1962.)

Although government authorities and the company had repeatedly stated from the start of the outbreak that "countermeasures would be taken once the causal element of Minamata Disease was known," neither took any action when it happened. The government also did not convey this information to companies throughout Japan which produced acetaldehyde utilizing the same process.

Two years later in 1965, the second outbreak of Minamata Disease occurred, this time in Niigata Prefecture. Clearly the political powers-that-be were responsible for this.

In spite of the Niigata outbreak, waste water containing methyl mercury from the Chisso Minamata Factory continued to be released into the sea until 1968, the year Chisso's acetaldehyde plant was shut down because it had become outmoded.

The same debate which had occurred in Minamata concerning the cause of the outbreak also took place in Niigata. Angry Niigata victims sued the polluting company Showa Denko. This in turn resurrected the issue in Kumamoto Prefecture that the cause of the illness and the polluter responsible for causing it had been left ambiguous. Pollution was on the increase in Japan as a result of the nation's intensive economic growth policies, and concern was growing among the public regarding environmental pollution.

On September 26, 1968, after much debate and discussion in the Diet and within the government, the Japanese government's Ministry of Health and Welfare issued an official statement which stated, "the cause of Minamata Disease was methyl mercury produced during the acetaldehyde production process at the Chisso Minamata factory." Putting aside the issue of the significance or insignificance of finding the actual causal compound when it was already known that waste water from the Chisso Minamata factory was the cause of Minamata Disease, this statement could have and should have been issued by 1963 at the latest. Instead, this government statement was not issued until four months after the Minamata Factory's acetaldehyde facility had been shut down. The facility had been shut down not out of concern for pollution, but, as mentioned above, because the production process which used mercury as a catalyst had become outmoded. Demand for acetaldehyde was now being fully met by petroleum technology.

In other words, the Japanese government allowed industry to use this polluting technology to its full extent without regard for public health and the environment, and only after it was no longer needed did it issue an official statement concerning the cause of the illness.

It is shocking that it is only in February of 1969, well after the polluting production process had been shut down, that the government designated the sea around Minamata a protected marine area, thereby restricting waste water containing methyl mercury from being released.

What Should Have Been Done To Implement Relief For Victims

It is correct to judge that the government had the responsibility to identify and give relief to victims of Minamata Disease based on the November 12, 1959 Ministry of Health and Welfare's Food Hygiene Investigation Committee's report. The report stated, "Minamata Disease, which results from the consumption of large quantities of fish and shellfish from Minamata Bay and the surrounding areas, is a food poisoning that attacks mainly the central nervous system. The main cause is an organic mercury compound."

It is evident that Kumamoto Prefecture was also aware of what needed to be done since in its 1959 annual report on Minamata Disease it had erased the words "unknown cause" and had replaced it with "food poisoning caused by consuming large quantities of fish and shellfish from Minamata Bay."

What was necessary was to investigate the nervous system disorders of people living around Minamata Bay and the surrounding Shiranui Sea who had consumed the polluted fish and shellfish, then follow up on the outcome. The effects of methyl mercury could have been identified and relief measures implemented had this population's nervous system disorders been compared to those not living in areas with mercury contamination. However, the political powers-that-be, wanting to declare Minamata Disease over, did not attempt to undertake any proper epidemiological study based on medical science.

Instead, they maintained a system by which only those who applied to the government could be medically examined to determine if they could be "certified" as qualifying to receive solatium payments from Chisso. And, worse, they never informed the public about this system or how to apply for it.

Because the illness had originally been considered a "strange disease" and contagious, it continued to be dreaded in Minamata and environs and victims of the pollution and their families continued to be persecuted. When the poisoning victims began to receive solatium payments from Chisso in 1960, people in the region would say, "These are lucky people. They can get money having fallen ill with this disease." This prejudice against victims occurred because under the system, Chisso continued to "give" money away to these victims without being made to take responsibility for having caused the illness.

Because the Minamata people feared being persecuted and feared this strange disease, they did not come forth even though they suffered from symptoms of Minamata Disease. The doctors in Minamata also did not tell their patients even when they suspected the illness. Minamata people felt it was humiliating to be afflicted with the disease and be certified as having it. This is still felt by a large segment of the population today.

If the political powers-that-be had officially declared Chisso to be responsible for having caused the poisoning and had assertively taken public health measures to relieve the victims, this feeling of shame and dread toward Minamata Disease would have been alleviated.

During the summer of 1960, Dr. Tokuomi Haruhiko of Kumamoto University Medical School conducted medical examinations of the populations in the Minamata region afflicted with the poisoning, finding many residents who complained of nervous system disorders. Only three of these people were recognized by the certification committee (the Kumamoto-Kagoshima Pollution Victims Certification Investigation Committee) which used the Hunter-Russell syndrome as its standard for certifying victims. Applicants had to have all the disorders of the syndrome to qualify.

Clinical researchers, because they cooperated with the government's certification system, did not pursue but rather abandoned further investigation of Minamata Disease in spite of the Tokuomi findings.

Because further research was abandoned, sensory disturbance, the most important symptom of Minamata Disease, was erroneously considered to be caused by damage to the peripheral nerves rather than the cerebral cortex of the brain.

In 1960, the government authorities and the Chisso corporation, taking advantage of the fact that victims were not coming forth to seek certification, declared Minamata Disease to be over.

In the meantime it had taken until November of 1962 for the recognition of congenital victims of Minamata Disease who suffered serious effects of methyl mercury poisoning due to exposure in their mother's womb. There is a great deal of circumstantial evidence which points to the fact that recognition of congenital victims was delayed because of political considerations that Minamata Disease would become an issue again and Chisso's financial burden would increase.

Continued Negligence Even After The Polluter Was Officially Recognized

By 1968, the government authorities and Chisso had successfully attained the following:

  • Confining the period of Minamata Disease occurrence to between 1953 and 1960.
  • Confining the geographical area of the poisoning to the Minamata Bay area and its immediate surroundings.
  • Confining the number of certified victims to 111.
  • Confining the Minamata Disease medical condition to typical Hunter-Russell syndrome, thus having further research on Minamata Disease abandoned and erroneous concepts concerning the poisoning maintained.
  • Keeping Chisso Corporation's compensation burden down to a minimum.

On September 26, 1968, when the government issued its statement concerning Minamata Disease, it appears that the government thought all would be resolved if the amount of compensation were raised a certain degree. However, this was not the case.

By then there were innumerable victims of mercury pollution throughout the Shiranui Sea, patients that had been ignored and not given relief since 1960, greater numbers of methyl mercury victims because not knowing that the fish continued to be seriously contaminated, people had continued to eat the fish.

After the 1968 government statement, a number of people were recognized by the certification committee as having contracted Minamata Disease. In 1969 five people, and in 1970 another five were certified. Other victims were told with no explanation that they did not have Minamata Disease. Actually, the real reason these latter people were not recognized was to keep the cost of compensation down to a minimum for Chisso. In February of 1970, Kumamoto Prefecture told the certification committee, "Undertake the examination and judgement giving consideration to how it will relate to compensation." It was also later revealed in a national newspaper that the question "if we certify as many as 5 people, will the Chisso corporation go bankrupt?" had been raised in the committee.

Government's Certification System Challenged By Victims

In 1970, Kawamoto Teruo who had been told by Kumamoto Prefecture that he was not a Minamata Disease victim submitted a plea to the Ministry of Health and Welfare to re-examine Kumamoto Prefecture's decision concerning him and eight other people.

During the year that followed, Kawamoto and supporters (including Dr. Harada Masazumi) proved that the diagnosis of the certification committee had been mistaken. They showed that severe methyl mercury contamination had spread throughout the Shiranui Sea and declared that therefore, if people who ate fish and shellfish contaminated with methyl mercury presented neurological disorders, they should be epidemiologiclly presumed to be influenced by this contamination.

In August of 1971, the government's newly established Environment Agency recognizing Kawamoto Teruo's assertion, overturning Kumamoto Prefecture's judgement. At the same time, the Environment Agency issued a directive which stated that a person's symptoms should be presumed to be Minamata Disease if he or she had continued to eat the contaminated fish and shellfish and manifested even one of the neurological disorders found in Minamata Disease. (In most cases this was sensory disturbance.) This is correct judgement from an epidemiological and public health standpoint.

The number of people who were certified gradually increased, and when in March of 1973 the verdict was handed down by the Kumamoto District Court finding Chisso legally responsible for having caused Minamata Disease, the number of certified victims increased even further. Chisso, no longer able to cope with the burden of compensation, sought relief from Kumamoto prefecture and the national government.

In 1977 the Environment Agency reverted back to the government's earlier position that a resident did not qualify as having Minamata Disease unless there was medical proof of multiple symptoms of the illness. As a result certification decreased rapidly, eventually reaching zero. Concurrently, the financial burden to Kumamoto Prefecture for financing Chisso's compensation costs became lighter.

Victims who decided that they could not receive relief from the political powers-that-be took Chisso, Kumamoto Prefecture, and the national government to court. Whether the victims won or lost the cases, the cases were appealed to higher courts. No one knew when the legal cases would be concluded. The corporation and government were institutions, unlike individual victims who were sick and dying. More and more, people wanted redress while they were still alive.

In 1995, the national government presented a settlement plan to those who had not been certified as Minamata Disease but were suing in the courts. The conditions for receiving payment were as follows: Victims would not be recognized as having Minamata Disease by the government's certification system; the government would not have any compensation responsibilities to the victims; the victims must withdraw their lawsuits.

Most victims decided to agree to the conditions of the government settlement. The government then acted to mediate this settlement between the Chisso corporation and the victims.

Under the conditions of the settlement, those who were recognized as having sensory disturbance of the extremities received 2.6 million yen from Chisso (financed by the national and Kumamoto prefectural governments) and relief for medical payment costs.

The government settlement was dubbed a "political solution." It was typically Japanese, full of ambiguities as to where responsibility lay.

It was well known in Japan that innumerable people have the medical condition Minamata Disease but have not come forth, or have the illness but are not recognized. In spite of this, the political powers-that-be pretended that Minamata Disease is a thing of the past, and are worked to have it become just that.

Minamata Disease Far From Over

Victims who had moved to the central Japan area of Kansai rejected the government's political settlement of 1995 and continued their lawsuit. On April 27, 2001 the Osaka High Court handed down a verdict recognizing the plaintiffs' claims. The court found the national and Kumamoto prefectural governments, by not attempting to take countermeasures concerning the Chisso waste water after 1960, responsible for failing to prevent the spread of Minamata Disease. The court found the national and Kumamoto governments therefore responsible for plaintiffs' compensation.

Rather than recognize this higher court decision, on May 11, 2001 both the national and prefectural governments appealed the case to the Japanese Supreme Court. The case continues with no date in sight for its conclusion.

The government authorities and Chisso must now be waiting for all victims to die. However, the fact that the Kansai lawsuit continues and the government has been unable to bring it down, and the reality that serious problems remain throughout the Shiranui Sea area signify that Minamata Disease is not over.

Addendum to this 2001 paper:

On October 15, 2004, the Kansai lawsuit plaintiffs won the Supreme Court case.

MIYAZAWA, Nobuo, a former NHK anchor reporter, is a freelance author who has researched Minamata Disease issues for 33 years. He has authored/edited numerous publications concerning Minamata Disease. He is the author of Minamata-byo Jiken Yonjuhnen (The Minamata Incident - Forty Years), Ashi Shobo, 1997.

Aileen Mioko SMITH, MPH, is co-author of the book "Minamata" with W. Eugene Smith. (Holt, Rinehart and Winston, 1975. ) She is director of Green Action, an NGO working to stop Japan's plutonium program.

(Minor English translation revisions made April 2006.)