Sixty-one years have passed since the first case of Minamata disease was discovered in 1956 in Minamata, Kumamoto Prefecture, but the issue of relief for victims of the disease — Japan’s most serious industrial pollution-induced illness — remains unresolved. Originally the disease was found among people who ate fish contaminated with organic mercury contained in waste water released into Minamata Bay by a Chisso Corp. chemical plant. But studies by a group of doctors conducted over a span of 13 years show that many residents from inland areas away from the coastlines of Yatsushirokai Bay, of which Minamata Bay is a part, exhibit symptoms peculiar to the disease.
The government should conduct medical examines on all residents in areas where such symptoms have been detected. This should be the basis for comprehensive assistance covering all Minamata disease victims, who are believed to number between 100,000 and 200,000, since relief is provided only to those officially recognized to suffer from the disease.
The history of relief for Minamata disease victims has followed a zigzag course. Beginning in 1969, a person with even a single symptom of the disease was officially recognized as a patient and received a one-off allowance of between ¥10 million and ¥18 million, and medical aid from the polluters — Chisso and Showa Denko KK, which was responsible for a similar case of mercury poisoning that afflicted residents in the lower reaches of the Agano River in Niigata Prefecture. In 1977, however, the old Environment Agency adopted strict criteria for screening the victims — under which a sensation disorder must be accompanied by other symptoms if one is to be officially recognized as a patient of the disease. The criteria were so strict that those officially recognized as sufferers numbered fewer than 3,000. Many of unrecognized sufferers resorted to lawsuits seeking damages.
Unrecognized Minamata disease victims point out that they suffered from the damage organic mercury caused to their central nervous system. In accordance with the degree of damage, the symptoms appear in gradation — from light to serious. The argument that exclusion of those with light symptoms from the relief scheme is unjust is reasonable.
In an attempt to expand the scope of relief for unrecognized victims, the government in 1995 worked out a settlement that included a lump sum payment of ¥2.6 million and medical allowances to such sufferers. But the ad hoc measure provided help to only some 11,000 victims since the application period for the relief lasted just six months.
In 2004, the Supreme Court ruled that a person should be officially recognized as a Minamata disease victim if he or she has a sensation disorder and meets one of three conditions — including having family member who is a recognized Minamata disease patient who displays a sensation disorder in the tips of their extremities. But even after the ruling, the Environment Ministry would not loosen or abolish the 1977 criteria, meaning many patients went unrecognized even if they exhibited symptoms attributable to the disease.
To help these victims, the government took a second step — providing a uniform ¥2.1 million in relief and medical allowances under a 2009 special law. Some 55,000 of the 65,000 people who applied by the 2012 deadline were given the assistance, but the law excluded people who had never lived in the Yatsushirokai coastal areas and did not have proof that they had eaten contaminated fish. Some of those who were excluded took their case to court seeking damages.
In 2013, the top court handed down a landmark ruling that a person who exhibits only a sensation disorder should be officially recognized as a Minamata disease victim if it is clear that the person had habitually eaten fish contaminated with organic mercury. But still the Environment Ministry would not ease or abolish the 1997 criteria, and issued a notice instead in 2014 based on the criteria — ostensibly with the intention of recognizing a wider scope of people who suffer from the disease. Under this decision, people who display a sensation disorder may be recognized as Minamata disease victim, but they must satisfy several other requirements, which include presenting documents showing that they lived or stayed in areas where contaminated fish was habitually eaten, an explanation on their dietary habits, and their family and occupational history.
In examining the records of some 10,000 people who received medical exams from 2004 through 2016, the group of doctors compared people who lived at least a year in the Yatsushirokai coastal areas and those who did not and found that 84 percent of those in the first group and 88 percent of those in the second group had a sensation disorder in their limbs. In either group, 27 percent suffered narrowing of their visual field. The findings prove that even in areas excluded from the government’s 2009 relief measures, fish caught in Minamata Bay was sold and residents ate contaminated fish. Today, more than 2,000 residents of Kumamoto and Kagoshima prefectures are waiting for screening for recognition as victims of the disease. In addition, some 1,400 unrecognized sufferers have filed lawsuits seeking damages.
The government has not responded to requests from Minamata disease victims, doctors and experts on pollution that it carry out comprehensive medical examinations to grasp the overall picture of damage from the disease. It should be aware of the likelihood that there are still large numbers of latent victims. Such an examination will be essential to full-scale relief for Minamata disease victims. It should end its foot-dragging and immediately start an all-embracing medical probe in wide areas.