It’s been called the worst industrial accident in history, and it’s not over. Thirty years ago, during the wee hours of Dec. 3, 1984, a catastrophic gas leak from a pesticide plant in Bhopal, India, killed at least 5,000 people, and sickened thousands more who later died or became permanently disabled. Up to 600,000 people were affected in all. Toxic pollution from the accident severely contaminated the soil and groundwater around the site, poisoning new generations who suffer from high rates of cancer, birth defects and developmental problems. The site needs to be cleaned up, but disputes over who should pay, and where and how the toxic waste should be disposed of, has led to tragic inaction.

Justice is another casualty of the disaster. The American chemical company Union Carbide owned a majority stake in the plant at the time. In 1989, Union Carbide paid just $470 million in compensation to the Indian government — an average of $2,200 to the families of the dead and $550 to the injured — and then washed its hands of the matter.

After hundreds of Bhopal survivors staged a hunger strike last month in New Delhi, India’s minister for chemicals and fertilizers, Ananth Kumar, agreed to revise the official number of victims and to pay out additional compensation. This is the least India’s government can do. It also needs to strengthen and enforce pollution controls on industry — smaller accidents occur with alarming frequency — and establish emergency procedures to deal with accidents when they occur.

Prime Minister Narendra Modi and President Obama, who are eager to increase business ties between India and the United States, will have an opportunity when Mr. Obama visits India in January to announce a joint effort, enlisting the private sector, to clean up the contaminated site at Bhopal. Dow Chemical should contribute substantially to the effort. The suffering and pain unleashed in Bhopal 30 years ago cannot be allowed to harm another generation.