MINAMATA, Japan – Determination takes on a special meaning here. Despite twisted limbs, tremors and confinement to wheelchairs, people afflicted by the world’s most infamous mercury poisoning still struggle for justice. As a new international mercury treaty is launched, they hope that no one ever again will suffer as they have.

Minamata’s rolling hills and striking beauty contrast with its brutal history. Chisso Corp. discharged methylmercury into Minamata Bay from 1932 to 1968, poisoning the city’s food supply. People who ate local fish developed Minamata disease – a debilitating condition in which they lose sensation in their hands and feet, can no longer run or walk without stumbling or falling and have difficulty seeing, hearing, speaking and swallowing. Many of the afflicted died.

For years, Chisso refused to take meaningful action to limit mercury poisoning from its emissions. Later, with the aid of the Japanese government, it split into two parts to limit its financial liability to Minamata disease victims. Though thousands of people suffered crippling illnesses, no independent, systematic health study of the Minamata region was ever conducted, so the total number of sickened people remains unknown.

Shinobu Sakamoto was born in 1956, shortly after reports of Minamata disease emerged. The mercury-contaminated fish eaten by her mother damaged her ability to walk and speak, and later the local elementary school rejected her. Instead of letting her disability deter her, Sakamoto became a leader among Minamata victims. In 1972, Sakamoto and her mother traveled to the UN Conference on the Human Environment, where she shocked a global audience with the visible harms of mercury. Forty-one years later, Sakamoto is still fighting for justice.

Although 2,273 individuals were officially recognized as Minamata disease patients as of 2011, tens of thousands experience neurological symptoms characteristic of methylmercury poisoning, but they remain formally unrecognized as Minamata disease patients. The discrepancy stems from the diagnostic criteria the government has used to certify Minamata disease. In 2004, the Supreme Court declared these criteria to be invalid, and last February, a newspaper reported that the Environment Ministry repeatedly requested a medical doctor to lie in a court case to prevent certification of Minamata disease. Approximately 65,000 have applied to the government for compensation.

Last Saturday, IPEN representatives from 25 countries listened in the rain as Yoshihiro Yamashita, a Minamata disease victim, stood outside Chisso’s main gate and animatedly explained how Chisso for years dumped wastewater contaminated with mercury into Minamata Bay. Yamashita knows because he used to work at Chisso. Yamashita described how eventually the majority of the bay was transformed as it was filled with the mercury-containing sediment. That sediment has now been turned into a massive landfill, capped with grass and dubbed an “Eco-Park.” The sludge under the park has been “temporarily” placed there for more than 30 years without any mercury removal. Vulnerable to both earthquakes and tsunamis, the site is now more than halfway through its expected 40- to 50-year lifespan, with no plan for remediation in sight. Hidden from view, it remains in a vulnerable location next to the Bay where it originally poisoned the community.

On Wednesday, a new United Nations mercury treaty was ceremonially launched at the “Eco-Park.” Leaders from around the world stood atop 1.5 million cubic meters of toxic mercury waste – an image that Minamata victims said they find strange and ironic.

During negotiations of the mercury treaty three years ago, Sakamoto personally handed a letter to a top government official from victims groups opposing the proposal to name the treaty the “Minamata Convention.” The letter uses polite language to express an underlying outrage that Minamata victims feel about naming the mercury treaty after their unresolved tragedy.

However, the concerns of Sakamoto and other victims extend far beyond their small city as the letter expresses the hope “for a strong global treaty which will significantly decrease mercury contamination worldwide so that fish are once again safe to eat.” The UN treaty seeks to reduce mercury supply and trade, and phase out or phase down some products and processes that use it. Some treaty provisions are legally binding, while others require governments to “endeavor” to take action.

At home, the Minamata victims hope the treaty will ensure that all are recognized and compensated, contaminated areas are cleaned up, the polluter takes full financial responsibility and a comprehensive, independent health study is finally conducted.

The mercury treaty now bears Minamata’s name. This creates a special obligation to meet the victims’ demands and transform a human tragedy into an opportunity for change.

This article originally ran at Environmental Health News, a news source published by Environmental Health Sciences, a nonprofit media company.