As the worst nuclear power plant disaster to date, the Chernobyl accident in 1986 had far-reaching effects. Total fallout from the accident eventually reached a level 10 times that of the atomic bomb dropped on Hiroshima, Japan, on August 6, 1945, at the end of World War II (1939–45). Some 30 firefighters and plant workers died just after the accident.

Plants and animals in the immediate area and downwind of the plant were heavily contaminated with radioactive fallout. More than 10 years after the accident, food crops still could not be planted in the region.

The immediate after-effects were felt in Europe as well: Some Italian vegetables were found to be contaminated; reindeer meat in Lapland (a region above the Arctic Circle and extending over northern Norway, Sweden, Finland, and Russia) was declared unfit for human consumption, also due to radioactive contamination; and for a time, fresh meat from eastern Europe was banned by the EC (European Community).

After the accident, some experts predicted disastrous long-term effects, estimating that between 6,500 and 45,000 people could die as a result of cancer caused by exposure to radiation. But a report issued by the World Health Organization (WHO) in 2000 concluded that “there is no evidence of a major public health impact attributable to radiation exposure 14 years after the accident. There is no scientific evidence of increases in overall cancer incidence or mortality or in non-malignant disorders that could be related to radiation exposure.”

Since the type of nuclear power plant (called RMBK) in use in the former Soviet Union is no longer in operation elsewhere in the world, non-Soviet scientists had few lessons to learn from the event. One American nuclear expert remarked that “most of the lessons from Chernobyl have been learned already and applied in the United States.” However, opinion remained divided over the relative safety of nuclear power in general.