The world has failed to help survivors of the Bhopal gas leak in India 20 years ago or to punish the guilty, Amnesty International says.
Survivors have been waiting for help for years
The human rights group says India's government has not distributed most of the nearly $500m compensation paid by US firm Union Carbide, the plant owner.
Nearly 3,000 people died on the night of the leak in 1984. There have been at least 15,000 related deaths since.
Survivors are still suffering chronic respiratory and other illnesses.
The report from London-based Amnesty International said "new research" revealed that more than 7,000 people had died immediately after the gas leak, while a further 15,000 people had died of related diseases since 1984.
"More than 100,000 people are suffering from chronic or debilitating illnesses," the report said.
The leak of tonnes of methyl isocyanate gas at the plant in the central Indian city of Bhopal owned by Union Carbide, now a subsidiary of Dow Chemical, led to one of the world's worst environmental disasters.
Bhopal activists said they hoped Dow Chemicals would now respond and help end people's suffering.
"This report comes as a morale boost to those of us who have been saying all this for a long time. Such a report will give weight to our voice," Abdul Jabbar, who runs a support group for gas victims, told the BBC.
Satinath Sarangi of the Sambhavna Trust, which provides health care to survivors, said: "The report shows the importance of documenting and fighting against human rights violations by corporations."
Amnesty said victims of the leak were yet to receive adequate compensation two decades after the incident.
"Despite the determined efforts of survivors to secure justice, the large numbers affected have received inadequate compensation and medical assistance," the group's 82-page report said.
More than 570,000 victims of the gas disaster have begun receiving a second instalment of compensation after Union Carbide, agreed a settlement in 1989.
Nearly $350m is being distributed from 15 November to individuals whose claims have been accepted. Money will be set aside for outstanding cases.
Amnesty said overall, efforts by survivors to get proper justice through both US and Indian courts had so far been unsuccessful.
"The transnational corporations involved... have publicly stated that they have no responsibility for the leak and its consequences or for the pollution from the plant."
The group also blamed the Indian government for not tackling safety problems at the plant, and negotiating a settlement "without the participation of the victims".
And its report said toxic material continued to contaminate water supplies around the plant site.
"The site has not been cleaned up so toxic wastes continue to pollute the water which the surrounding communities rely on."
Amnesty wants better compensation and treatment for the victims and the plant site to be decontaminated.
Dow Chemical denies any continuing liability either for the state of the Bhopal site or for the victims' health.
An eight-word statement on its website reads: "Dow never owned or operated the Bhopal plant."
A New York court has yet to rule whether the company should still be responsible for clean-up costs and victims' compensation, while a criminal case is also pending in Bhopal itself.
Amnesty International is demanding that Dow Chemical agrees to participate in the Indian-based case despite its 1989 settlement.