70 Years of Minamata Disease: Don’t Forget Vital Lessons Learned from Industrial Pollution

Editorial

16:03 JST, May 1, 2026

Minamata disease is considered to be the starting point of Japan’s industrial pollution problems. Seventy years have passed since the disease was first officially confirmed, yet the path to victim relief is still only halfway complete. As the sufferers continue to age, it is the duty of the government to provide relief and support to as many people as possible.

Minamata disease, a form of poisoning in which the nervous system is damaged by methylmercury, was officially recognized on May 1, 1956. Mercury was discharged into the sea from the Chisso factory in Minamata, Kumamoto Prefecture, and residents who consumed contaminated seafood developed the disease.

The total number of people officially recognized as patients in Kumamoto and Kagoshima prefectures reached 2,284. However, there are also many unrecognized victims, and the government has provided lump-sum payments to more than 40,000 people through such means as enacting a law to offer financial relief to people who have yet to be recognized.

Those excluded from the government’s relief measures have filed lawsuits, and the legal battles are still ongoing. There are about 1,500 plaintiffs, and the average age is 75. In individual cases, judicial rulings have been split on whether relief should be provided.

The relief law stipulates the responsibility of the central and local governments, stating that they must work to provide relief to all eligible individuals as much as they can and resolve the issue. They should engage in repeated dialogue with the plaintiffs and others and consider relief measures that can be agreed upon.

At the time when Minamata disease was first recognized, Japan was entering a period of rapid economic growth. Economic activities were prioritized, and neither the central government nor corporations took the damage seriously. Their response was slow, ultimately leading to a new disaster known as Niigata Minamata disease in which people suffered from methylmercury poisoning.

The discharge of PFAS — a chemical substance suspected of being carcinogenic — into rivers, marine pollution due to plastic waste and other such problems have been major issues in recent years. It is crucial to apply to the present day the lessons learned from past industrial pollution issues that a heightened sense of crisis and quick response are important.

There are also signs that the issue of Minamata disease is fading from public consciousness.

Last year, the Uki municipal government in Kumamoto Prefecture distributed calendars to all households in the city that described Minamata disease as an “infectious disease.” The company operating the “Katei Kyoshi no Try” home tutoring service had been disseminating information describing Minamata disease as “hereditary” for nearly a decade.

Both of these are incorrect. Minamata disease is not an infectious disease like COVID-19. Although a fetus can be affected through the mother, the disease is not hereditary. It is necessary to convey information accurately. If disinformation spreads, it could fuel discrimination and prejudice.

Health hazards caused by mercury remain a problem in developing countries today. Methods involving the use of mercury in gold refining are common, and mercury discharge into rivers has been confirmed.

Based on the lessons learned from Minamata disease, an international treaty regulating the use, import and export of mercury came into effect in 2017. Japan should take the lead in coordinating with other nations and regions to support “mercury-free” initiatives.

(From The Yomiuri Shimbun, May 1, 2026)