The British Medical Journal today reported that the largest international study ever conducted on radiation workers, found only 1-2 per cent of cancer deaths among study participants could be attributed to low doses of radiation, and confirmed that current international radiation protection standards have been constructed on an accurate base.
“The study of 407 000 radiation workers from 15 countries was critical in confirming that radiation protection standards, that have been largely based on data from survivors of the atomic bombs dropped on Japan, were valid,” said Professor John Kaldor, epidemiologist from the University of NSW who was involved in designing and analysing the study.
“Those involved in conducting the study were aware that the cancer risk was small at the radiation levels workers are generally exposed to, so a really large study was needed in order to statistically detect any risk,” he said.
“We now have direct evidence that the standards currently in use are supported by real data on people who work in the industry.”
Dr Ron Cameron, ANSTO Chief of Operations said that ANSTO was pleased the study confirms the viability of current radiation protection practices.
“The recently published study of 7 076 ANSTO radiation workers, many of whom were included in the international study, showed that rates of overall mortality and death from cancer were 31 per cent and 19 per cent below the national average.
“In addition, while international guidelines state the annual dose for radiation workers should not exceed 20mSv, the average ANSTO worker receives only 1mSv per year and those working in the most active areas, less than 10 mSv. Therefore, ANSTO operates well below accepted levels,” said Dr Cameron.
The study estimated that cumulative exposure of 100 millisieverts (mSv) would lead to a 10 per cent increased mortality from all cancers, excluding leukaemia. However it was noted that less than 5% per cent of the workers in the combined study received cumulative doses of 100 mSv over their career, with most of these receiving them in the early years of the industry when standards were less stringent. These figures allowed statisticians to deduce that 1-2 per cent of cancer deaths in the study may have been due to radiation.
The study was directed by the International Agency for Research on Cancer in Lyons, France.
Published: 29/06/2005