KUMAMOTO--The district court here March 30 ruled against seven people seeking official recognition as Minamata disease patients, thereby depriving them of eligibility to receive state assistance for their medical treatment.

The plaintiffs had called for decisions by the Kumamoto and Kagoshima prefectural governments on the issue to be revoked.

The presiding judge dismissed their requests on grounds the court could not recognize them as Minamata disease patients based on the arguments their lawyers presented. The plaintiffs vowed to appeal the ruling.

The seven, who are aged between 62 and 69, were all born and raised in coastal communities of the Kyushu region along the Sea of Shiranui around the mid-1950s when Minamata disease was first officially recognized.

Minamata disease was caused by mercury poisoning due to the dumping of industrial wastewater by a chemical factory operated by Chisso Corp. into the sea off Minamata, Kumamoto Prefecture.

The disease was firstly reported and officially confirmed by health authorities in 1956 in Minamata.

The plaintiffs contended they contracted Minamata disease as fetuses or as small children during the period when methylmercury pollution of the Sea of Shiranui became a serious problem and patients with severe symptoms emerged one after another.

Chisso was founded in the early 20th century.

The plaintiffs requested that the Kumamoto and Kagoshima prefectural governments grant them official recognition under the Pollution-Related Health Damage Compensation Law, arguing they had suffered numbness or tremors in their hands and feet, as well as leg cramps, since they were small children.

Both prefectural authorities refused to do so, prompting the plaintiffs to file their lawsuit in October 2015.

The prefectural governments contend that the plaintiffs’ symptoms are less likely to have been caused by methylmercury and instead could be due to diabetes or neurological disorders caused by alcohol consumption.

The ruling accepted that all seven plaintiffs were exposed to methylmercury to some extent. It even acknowledged that some of them experienced severe exposure to methylmercury.

However, because their symptoms only started emerging 20 to 30 years after they were free from exposure to methylmercury, the court ruled it is impossible “to reasonably explain” a link.

The ruling also noted that the plaintiffs experienced sensory disorders such as numbness, typical symptoms of Minamata disease, but only intermittently.

Taking these factors into consideration, the ruling concluded it was “impossible to deny that their symptoms could be caused by other diseases.”

The parents or grandparents of some of the plaintiffs are officially recognized as Minamata disease patients.

In a separate development, eight people including the seven plaintiffs in this case, lost a lawsuit in which they sought damages from the central government, the Kumamoto prefectural government and Chisso.

In March 2020, the Fukuoka High Court overturned a verdict by the Kumamoto District Court that ordered the defendants to pay damages to three of the plaintiffs. In dismissing the demand for damages made by all of the eight plaintiffs, the high court said their symptoms, such as sensory disorder, including numbness, could have been caused by other diseases, not methylmercury.

On March 8, the Supreme Court dismissed the plaintiffs’ appeal, leaving them with no room to take further legal action.

After the March 30 verdict, the seven plaintiffs and their supporters expressed frustration with the ruling, which they complained simply accepted the arguments put up by the two prefectural governments.

“This ruling was written by someone who doesn’t know the first thing about Minamata disease,” said Hideki Sato, the 67-year-old leader of the plaintiffs’ group, after the verdict. “They should learn more about it.”

Sato was born in a fishing village called Modo in Minamata, where many patients suffering from the disease have been recognized. His grandmother and parents were among them.

His mother’s symptoms were so extreme she was unable to walk. His grandfather also suffered from severe convulsions before he died. Sato argued in the trial that he, too, had to endure tell-tale Minamata symptoms since he was a child.

Although the court accepted that Sato was exposed to highly concentrated methylmercury, it said the relationship between it and his symptoms is “not necessarily obvious.”

Sato was clearly livid with the ruling.

“The court believes the argument of the administrative body, without recognizing our suffering. This is discrimination by the court. It cannot be forgiven. I will fight till the end.”

Ryosuke Saeki, a lawyer representing the plaintiffs, said the court ignored the fact that the plaintiffs only started seeing doctors in recent decades, even though they had suffered from the symptoms since they were children.

(This article was written by Masamitsu Oku, Shomei Nagatsuma, Rina Horikoshi and Makoto Hokao.)