February 2000
Nuclear leak worse than first feared - More than 400 were exposed to radiation in Japan
The Guardian, February 2, 2000
By Jonathan Watts in Tokyo[Posted 02/02/2000]
Japan's worst nuclear accident exposed nearly five times as many people to radiation as wasoriginally thought, the government said yesterday.
The sharp upward revision of the impact of the uncontrolled chain reaction on September 30 is a fresh blow to public confidence in a nuclear industry that has suffered a series of accidents and cover-ups over the past few years.
Japan's science and technology agency revealed that 439 people were exposed to neutron rays during the 20 hours in which the nuclear fission took place at a uranium processing plant in Tokaimura, 80 miles northeast of Tokyo.
In its initial report, the agency said only 69 people were affected. The accident occurred when plant workers used buckets to mix nearly eight times the correct amount of condensed uranium.
According to the agency's revised figures, the resulting fission exposed 119 residents, plant workers and emergency service staff to more than one millisievert of radiation, which is the annual permissible level.
It is the first time that an accident in Japan has affected more than 100 people to such an extent.
One worker who battled to halt the chain reaction suffered as much as 38 millisieverts and ambulance crews who arrived without being told they were visiting a nuclear accident site were exposed to high levels of radiation.
The agency played down the health implications of its findings, saying that the risks of cancer only increased significantly with a dose of more than 50 millisieverts. It said the revised figures were higher because the later assessment included local residents.
"This makes the number look bigger than the original figures we reported," an agency official told reporters.
Anti-nuclear groups, however, said the data under played the seriousness of the accident.
"We still don't think this is an accurate figure. It doesn't include any people passing through the area at the time or those who were working in nearby fields," said Kazue Suzuki of Greenpeace Japan.
The average incidence of leukaemia is 0.66% in Japan. According to the International Commission of Radiological Protection, the risk increases by 0.05 points for every 10 millisieverts of exposure.
The new figures are likely to add to public concern about the safety of the nuclear industry. Since the chain reaction, several local governments have halted or cancelled nuclear energy projects.
In the atmosphere of increased safety consciousness, British Nuclear Fuels Ltd has lost contracts as a punishment for supplying reprocessed fuel with falsified safety data.
Health officials have offered to monitor 120 people affected by radiation.
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