The government's arbitration commission for pollution-related disputes ruled Wednesday that a public waste-processing facility in Tokyo's Suginami Ward caused a number of illnesses among residents in 1996.

However, the Environmental Dispute Coordination Commission said it was unable to specify which chemicals had contributed to "Suginami Disease," a series of ailments including eye and skin irritation, chest pain, respiratory problems, headaches and dizziness.

The Tokyo Metropolitan Government began operating the household-waste processing facility in April 1996. Residents began reporting symptoms of the disease the same month.

The commission also relayed its decision to related administrative bodies — the Environment Ministry, the metropolitan government, and Suginami Municipal Government — telling them to take appropriate measures.

The metropolitan government said later in the day that it will deal with the matter after closely examining the decision.

According to the commission, it is almost impossible to specify and prove that certain chemicals had caused certain symptoms, even after analyzing hundreds of chemical samples taken from the facility.

The characteristics of many forms of chemical poisoning remain unknown to modern science, the commission said.

Hydrogen sulfide, which was drained by from the facility, was mentioned by the commission as a possible cause of some of the symptoms.

The commission recognized 14 of the 18 residents who filed complaints as suffering from Suginami Disease.

In July 1996, after receiving complaints from local residents, the metropolitan government stopped draining waste water containing chemicals from the facility directly into the sewage network. In September that year, residents reported a drastic improvement in their conditions.

The facility is still in use.

Roughly 2,000 people live in the area, which includes Igusamori Park.