NIIGATA – A district court has ordered the Niigata Municipal Government to officially recognize seven people as sufferers of the Minamata mercury-poisoning disease.

But the Niigata District Court also rejected the claims of two of the nine plaintiffs fighting for recognition over one of the country’s worst outbreaks of illness linked to industrial pollution.

The ruling Monday was the first ever on people who specifically contracted the disease from mercury-tainted waste water that came out of a Showa Denko K.K. chemical plant in Niigata Prefecture in the 1960s.

“I’m satisfied with the ruling,” the head of the plaintiffs, a 50-year-old man, said afterward, while still lamenting that two of their group were not recognized as victims.

Their lawyers said they plan to appeal the decision for those two people.

The court recognized that for milder cases of Minamata disease, patients only exhibit a single symptom of disorder of sensation. The decision reflects a Supreme Court ruling in April 2013 that allowed recognition for sufferers who display only a single symptom.

The Environment Ministry’s Special Environmental Diseases Office said it will “closely examine” the ruling and “watch carefully” the response of the municipal government.

The nine plaintiffs, aged 50 to 80, applied with the city from 2005 to 2011, saying they ate fish that was contaminated by mercury-tainted waste water and developed symptoms such as loss of sensation in their limbs.

The plaintiffs said the city rejected their claims based on the government’s criteria adopted in 1977 where people are certified if they suffered from a combination of symptoms.

The stricter 1977 standards led more applications to be rejected and prompted victims to bring their cases to court.

Citing the Supreme Court’s decision, the plaintiffs argued that the criteria are “wrong from a medical viewpoint” and that they exhibit disorder of sensation, at the very least.

The municipal government has said it is uncertain whether the plaintiffs did suffer from loss of sensation, and if so, whether it was directly linked to Minamata disease. The court said the loss of sensation for the two plaintiffs who were turned down may have been caused by other factors.

The disease was detected in Niigata in 1965. Health authorities officially recognized the disease in 1956 after it was first discovered in Kumamoto Prefecture, where it was caused by Chisso Corp.

As of the end of April, only 2,985 of 29,358 applicants in the affected prefectures of Kumamoto and neighboring Kagoshima and Niigata have been officially recognized as eligible for aid. Most were recognized before the 1977 standards were introduced.