LONDON -- The 20th anniversary of the Chernobyl nuclear accident of April 26, 1986, is prompting a new wave of alarmist claims about its impact on human health and the environment. As has become a ritual on such commemorative occasions, the death toll is tallied in the hundreds of thousands, and fresh reports are made of elevated rates of cancer, birth defects and overall mortality.

This picture is both badly distorted -- and harmful to the victims of the Chernobyl accident. All reputable scientific studies conducted so far have concluded that the impact of radiation has been less damaging than was feared. A few dozen emergency workers who battled the fire at the reactor succumbed to acute radiation sickness. Studies are still under way into elevated rates of cancer and cardiovascular disease among the "liquidators" who worked at the reactor site in the months following the accident. And some 5,000 cases of thyroid cancer, attributed to radioactive iodine absorbed through consumption of milk in the weeks immediately following the accident, have been detected among those who were children at the time.

There has been real suffering, particularly among the 330,000 people who were relocated after the accident. About that there is no doubt. But for the five million people living in affected regions who are designated as Chernobyl "victims," radiation has had no discernible impact on physical health.