Nearly 26 years after a toxic gas leak killed thousands in Bhopal, India, seven former executives of U.S. chemical giant Union Carbide’s Indian subsidiary were found guilty of negligence Monday and sentenced to two years in prison.

The trial represented the first criminal convictions in one of the world’s worst industrial disasters. But victims and activists declared the sentences as wholly inadequate.

“Victims here believe that rather than a deterrent, this judgment is actually an encouragement for companies to work in a dangerous fashion,” said Satinath Sarangi, a metallurgist and founder of the Bhopal Group for Information and Action. “They know that they will get away with mass murder.”

In the early hours of Dec. 3, 1984, a pesticide factory owned by Union Carbide India Ltd. in the central Indian city of Bhopal released approximately 40 metric tons of deadly methyl isocyanate gas.

The poison spread on the wind, exposing an estimated half a million people, many of whom woke up coughing, blinded and vomiting. The Indian government said the disaster killed 3,500 people, while activists put the number as high as 25,000.

Thousands more have lived with cancer, blindness, respiratory problems, mental retardation and immune, neurological and reproductive disorders.

Particularly galling for many was the verdict’s lack of mention of Warren Anderson, who was Union Carbide’s chief executive at the time and who jumped bail and fled to the United States after the disaster.

India maintains a arrest warrant for Anderson, now 89. The United States has been unable or unwilling to extradite him even though Greenpeace activists located him in on New York’s Long Island in 2002.

“Why was Anderson’s name not included when he was the main culprit,” said Maria Fernandez, an activist in Bhopal. “When you consider how long the families have suffered, under trauma, and he goes free, it’s not at all fair.”

The seven people who were convicted, all Indian nationals, were released on $530 bail and are expected to appeal, leaving some question that they will serve any prison time. Each defendant was also ordered to pay a fine of $2,100. An eighth person named in the conviction has since died.

Union Carbide India Ltd. was fined $10,600. But it’s not clear the fine will ever be paid: Michigan-based Dow Chemical Co. acquired Union Carbide, the parent company, in 2001 and has denied any inherited responsibility for the incident or its aftermath.

A report released late last year by Bhopal Medical Appeal, an advocacy group, said groundwater tested last June had 2,400 times the recommended safe levels of carbon tetrachloride, a known carcinogen banned from U.S. consumer products in the 1970s.

Indian courts, with an estimated 30 million cases pending, are notoriously creaky and it’s not unusual for a trial to take decades.

Local TV news channels voiced outrage at the verdict. “Black Monday again,” said one. “A Mockery of Justice,” said another.

Victims protesting in front of the courthouse lashed out at the courts, politicians and government for the verdict and for allegedly failing to hold the U.S. company accountable.

“They are puppets in the hands of the U.S.,” one victim told local reporters. “How can our prime minister show his face to the world after this verdict,” said another.

Among those convicted was Keshub Mahindra, the then-chairman of Union Carbide India Ltd. and now chairman of Mahindra and Mahindra Group, one of India’s largest corporations.

Over the years, “Bhopal” has become shorthand for corporate irresponsibility, fueling debates over multinational morality, the environment and codes of conduct.

Union Carbide agreed in 1989 to a $470-million out-of-court settlement with the Indian government that absolved it of further liability. Many victims and survivors got about $500. Tens of thousands of people, unable to navigate the complex registration process, received nothing, critics said.

“This is one such case where justice is delayed and practically denied,” said Law Minister M. Veerappa Moily. “I would like to say justice is buried.”

mark.magnier@latimes.com

Times staff writer Magnier reported from Bangalore and special correspondent Rana from New Delhi.