When Anatole Hrytsak collapsed last October while out buying bread and two weeks later had both of his legs amputated at the knees, he was certain that the night of April 26, 1986, had finally caught up with him.

Hrytsak, 56, was an engineer working at the Chernobyl nuclear power plant when an explosion ripped through one of its four reactors, emitting a huge radioactive cloud in the worst nuclear accident in history.

Hrytsak's doctors, however, were not convinced that radiation exposure was the cause of his chronic circulation problems. "They said, 'Maybe Chernobyl but maybe also smoking,' " Hrytsak said. "No one seems to know for sure."

Uncertainty about the long-term health consequences of the catastrophe at Chernobyl has generated an angry debate here. The discussion has been stoked by a major new report from eight U.N. agencies that concluded the accident has caused fewer than 50 deaths directly attributable to radiation.

The U.N. scientists predicted about 4,000 eventual radiation-related fatalities among 600,000 people in the affected areas, including plant personnel, emergency workers and residents.

Some early estimates had put the ultimate death toll at tens of thousands. After hearing numbers like that, hundreds of thousands of people lived with what they presumed to be a death sentence.

But authors of the report argue that if people are dying, it's often because they were told they would and therefore lived as if they would.

"Many of the health effects in the population of the Chernobyl-affected regions are caused by factors other than radiation," Burton G. Bennett, the American chairman of the group that conducted the study, said in a statement made at the conclusion of the group's meeting in Vienna. "That is not to belittle the possible consequences of radiation exposure, but it is to recognize the harm done by smoking, excessive alcohol consumption, poor diet or inadequate health care."

Most people suffered radiation doses that were "relatively low and unlikely to lead to widespread and serious health effects," Bennett said.

The report has drawn contradictory responses from governments in the region. Some officials in Russia, the republic that dominated the Soviet Union before its breakup, suggested that the report may in fact have been pessimistic.

"Talking about radiation effects, I think the figure of 4,000 is the maximum," said Nikolay Shingarev, director of information at the Ministry of Atomic Energy in Moscow. "The Chernobyl accident happened during a very difficult period in the Soviet Union. Life expectancy dropped considerably, but not because of radiation. The report figures did not come as a surprise. There is science and there are facts and we accept them."

What ostensibly should be good news has been derided in Ukraine and Belarus, where hundreds of thousands of people receive social and medical benefits because of the accident.

"We cannot agree with this data," said Tetyana Amosova, Ukraine's deputy minister of emergency situations. Ukraine, she said, is paying benefits to the relatives of the more than 17,000 people who worked in the cleanup and have died over the past 19 years.

Officials in Belarus also objected. "We cannot approve the report, and we have a lot of arguments with it," said Vladimir Tsalko, chairman of a government committee on the consequences of the Chernobyl disaster. "We do not agree with a lot of figures."

Officials in both countries said they planned to write rebuttals to the report in the coming weeks and would demand revisions in the final text.

"It's absolute stupidity," said Volodymyr Usatenko, who advises a Ukrainian parliamentary commission on Chernobyl. "I was absolutely stunned. The people who worked at Chernobyl were young, fit, psychologically healthy young men in 1986. And they have been dying at a much higher rate than any similar group of men who were not affected by Chernobyl. You can't say it's all because they led an unhealthy lifestyle after Chernobyl. That's not sufficient."

Local and international environmental organizations, including Greenpeace, also object to the findings, saying they grossly underplay the human and environmental devastation. But U.N. officials stand behind their work, saying it reflects years of study by some of the best scientists in the field and is consistent with death-rate trends that emerged from 50 years of study of the atomic bombings of Hiroshima and Nagasaki in the final days of World War II.

"If they are paying death benefits, that's their problem," said Michael Repacholi, manager of the World Health Organization's radiation program, which took part in the study. "We have solid data on the projected number of deaths that could be expected. People think they got massive doses, but they didn't, they really didn't."

Repacholi said the pervasive fatalism that consumed the survivors and contributed to widespread alcoholism and heavy smoking explained many of the deaths that people would like to believe were caused by radiation.

In Hrytsak's massive apartment block, where scores of workers were resettled, funerals have been a regular event for the last 15 years, according to Hrytsak. Two of his immediate neighbors died in the past six months, one from pancreatic cancer, the other from kidney failure.

"I am one of the few who is still alive," Hrytsak said, adding that about 70 of the 120 people he knew by name at the plant had died. "All of us are dying. I was appalled by the U.N. report. They should come and talk to people in this area."

But near the nuclear plant, which now sits inside an exclusion zone that extends 19 miles in all directions, the U.N. report received support.

"It's not radiation but psychological stress that's been killing people," said Serhiy Parashyn, head of administration in the zone, where nearly 9,000 people continue to work to decommission the reactors, the last of which was shut down in 2000.

"Many people lost their sense of life," he said. "And that's one of the main lessons of this accident. If it happens again, somewhere in the world, how do you work with the population so they get the right information?"

The exploded fourth reactor of the Chernobyl plant is seen in a 1986 aerial view. The U.N. report concluded the accident caused fewer than 50 deaths directly attributable to radiation and predicted about 4,000 eventual fatalities."I am one of the few who is still alive," said amputee Anatole Hrytsak, who worked at Chernobyl. "I was appalled by the U.N. report."