In the early morning hours of December 3, 1984, deadly gas leaked from a Union Carbide pesticide factory in Bhopal, India. The accident would result in the worst industrial disaster of the 20th century.  As many as 7,000 people died that day. Tens of thousands more were poisoned by the toxic cloud of methyl isocyanate fumes that blanketed the city. In subsequent years, many of those people died or suffered from the lingering side effects of the chemical leak.


The human rights group Amnesty International has marked the 20th anniversary of the disaster by releasing a report titled Clouds of Injustice. The report calls on Dow Chemical Company -- the owner of the Bhopal facility since 2001 - and the Indian government to clean up the site and fairly compensate the victims. Amnesty also proposes bringing the U.S. company before Indian courts. 


Bhopal has never fully recovered from the disaster. The abandoned pesticide factory is still contaminated by toxic waste. Health experts say local water supplies remain unsafe to drink, and people in the area continue to be sickened by the lingering chemical poisons. 150,000 people have been afflicted with health problems related to chemical exposure, including cancer, kidney disease, and mental illness.


"We have been able to document pretty extensively the widespread environmental contamination of the subsurface groundwater in the Bhopal area that affects at least 16 residential communities that we are aware of,? says Attorney Rajan Sharma, who has represented Bhopal survivors since 1999 in lawsuits against the chemical company. The problem, he says, ?emanates from an abandoned Bhopal plant where thousands of metric tons of toxic waste continue to be stored above ground, as well as a poorly secured landfill that was built on the plant campus."


The Amnesty report says that, before the Bhopal accident 20 years ago, Union Carbide -- now a wholly owned subsidiary of Dow Chemical -- failed to establish an emergency plan and ignored safety warnings. The report says that, after the disaster, the company withheld information critical to the medical treatment of victims. Amnesty argues that Union Carbide/Dow must assume liability for the Bhopal disaster. 


Executives of Union Carbide/Dow declined to respond to direct questions from reporters. But, in a company-produced audio statement, Dow spokesman Tom Sprick said his firm disclaims responsibility for the Bhopal disaster and its aftermath. "The plant was managed and run by Union Carbide,? he said, ?and managed and run by Union Carbide India Limited, a company owned by Union Carbide, Indian financial institutions and private investors. Union Carbide India Limited spent more than two million dollars on clean-up activities at the site up and through 1994. In 1998, the Madhyra Pradesh state government took control of the site and assumed all future responsibilities for the clean-up."


In 1989, Union Carbide and Union Carbide India entered into a $470 million negotiated settlement, which Mr. Sprick says was affirmed by the Indian Supreme Court as "just, equitable and reasonable."


But critics of the settlement say the Indian government failed to consult Bhopal victims before accepting the compensation package.  Survivors received an average of $500. The author of the report by Amnesty International, Vijay Nagaraj, says that sum has brought little relief. "Basically it is about survivors and victims standing in long lines in hospitals,? he says, ?where, after the wait of several hours, they are handed pills of different colors with very little explanation as to what this is going to do to them. Most of the time it does very little other than to relieve some symptoms temporarily. And it means also slipping into a cycle of poverty because of indebtedness [for] private health care." 


The Bhopal legacy is also a concern of environmental activists like Rick Hind, who heads the Toxins Campaign for the group Greenpeace. He alleges that the disaster is an example of environmental racism. "Had this happened in the United States," he says, "there is no doubt that Dow Chemical would be paying for the cleanup that would be ordered by the E.P.A. [the federal Environmental Protection Agency] or through litigation by community folks." 


Mr. Hind says the U.S. corporation is taking advantage of the differences between countries. ?Dow really at their own peril resists this liability,? he says. ?Responsible stockholders should remind them that we don't want to pay for the extensive contamination that will occur five or ten years from now when and if this litigation is dragged out any further. Every day it is delayed the contamination and the suffering of the people becomes worse."


In 2003, the Indian government unsuccessfully sought the extradition of Dow's chief executive on charges of culpable homicide. A class action lawsuit is still pending against Union Carbide. The Amnesty International report calls on Union Carbide/Dow to face trial in Bhopal.  It also recommends that international companies adopt universal plant and worker safety rules to guard against future disasters like Bhopal.