The Environment Ministry said Wednesday it has rejected demands from four people to be officially recognized as sufferers of Minamata mercury-poisoning disease, under new criteria adopted in March.
Following recommendations by an ad hoc certification panel, the ministry made its first judgments on applications for official recognition under the new criteria.
The ministry loosened the criteria after the Supreme Court posthumously recognized a woman with a sensory disorder as a sufferer of the disease last year. The woman has not satisfied the previous criteria, which required multiple symptoms, including limb trembling.
The new criteria say that a single symptom is sufficient if it can be proved to be the result of the consumption of fish or other foods contaminated with methyl mercury.
After the criteria was changed, the Minamata disease certification panel convened in April for the first time in 12 years.
Earlier this month, the panel examined the cases of the four people, each of whom has a single symptom. But it could not confirm any causal relationship between their symptoms and methyl mercury poisoning.
The work to certify Minamata disease sufferers was commissioned by the central government. It was previously carried out by the prefectural governments of Niigata, Kumamoto and Kagoshima, and the city of Niigata.
Following the Supreme Court ruling, however, the Kagoshima and Kumamoto governments suspended the work, calling on the national government to carry out unified screenings.
A total of 38 people, including the four who were rejected, switched their requests for certification from their municipalities to the panel.
The panel will examine applicants who provide adequate materials, such as the results of health checkups.