NUCLEAR TEST PARTICIPANTS: MORTALITY CANCER STUDY (Hansard, 9 December 1993)

The Parliamentary Under-Secretary of State, Ministry of Defence (Viscount Cranborne)

The Joint National Radiological Protection Board/Imperial Cancer Research (NRPB/ICRF) study into Mortality and Cancer Incidence amongst Nuclear Test Participants, commissioned by the Ministry of Defence, will be published on Saturday 11 December in theBritish Medical Journal after having successfully completed independent peer review. There will also be an accompanying NRPB report.

The NRPB is an independent statutory body which was set up to give advice on radiation protection. The ICRF is a charitable organisation which plays a leading role in cancer research. The authors of the report include eminent scientists who have published widely in the field, amongst whom is the distinguished epidemiologist Professor Sir Richard Doll, OBE, MD, DSc, FRS, FRCP, Emeritus Professor of Medicine at the University of Oxford, who is well known for his work on smoking-related disease.

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The Ministry of Defence accepts the findings of this independent report. The study concludes that participation in the nuclear weapon test programme has had no detectable effect on participants' expectation of life, or on their risk of developing cancer or other fatal diseases.

A report published by the NRPB in 1988 dealt with mortality and cancer up to 31 December 1983 among former test participants, compared with a control group of Service and civilian personnel matched for age, sex and rank who served in tropical areas at the time of the tests but were not themselves participants in the atmospheric nuclear weapon test programme. This study found no overall excess of death, or of cancer, among former participants compared with national rates. Out of over 20,000 former test participants, about 1,600 had died, including 400 from cancer (no more than amongst the matched control group or the general population). Of these 400, 22 had died of leukaemia and six from multiple myeloma, figures higher than the control group but similar to those expected from national rates. The authors considered that one possibility was that these elevated levels simply reflected an unusually low incidence of myeloma and leukaemia among the control group.

The follow-up report to be published in the BMJ includes cancer and mortality data to 31st December 1990. During the seven years between the end of 1983 and the end of 1990, about 1,200 further deaths occurred among former test participants, 370 of them from cancer. Again, these figures were no higher than among either the general population or the matched control group. Of the 370 further cancer deaths among participants, three were from multiple myeloma and six from leukaemia. The three deaths from myeloma were fewer than among the general population and the control group. Taken together with the figures from the previous study, for all deaths up to 31st December 1990 there was no increased incidence of multiple myeloma among participants compared with either the general population or controls.

The six deaths from leukaemia amongst participants between 1st January 1984 and 31st December 1990 were fewer than expected from national rates and fewer in veterans than amongst the controls. Furthermore, the total number of deaths for the entire period of both studies up to the end of 1990 from leukaemia was exactly the same as expected nationally. The excess of leukaemia in test participants compared with the control group found in the previous study is therefore likely to be a chance finding, although the report states that the possibility that test participation may have caused a small risk of developing leukaemia in the early years after the tests, cannot be completely ruled out. The study however, finds the evidence for a causal link to be weak for several reasons. First, the highest increase amongst participants was not among men in groups whose duties gave them the potential for exposure to ionising radiation, nor among men employed by the Atomic Weapons Research Establishment or directly involved in the minor trials at Maralinga, in whom undocumented inhalation or ingestion, if any, was most likely to have 84WA occurred. Second, the recorded doses of external radiation were very small, and on the best evidence now available, would have been estimated to cause not even one extra induced case of leukaemia. Third, there was no evidence of an increasing risk with increasing dose, as would be expected if caused by exposure to ionising radiation.

The Ministry of Defence has also compiled for the NRPB an environmental monitoring report for Christmas Island. I am arranging for a copy to be placed in the Library. This report shows that measurements of radioactive fall-out taken at the time of the tests were usually below the limit of detection. On the few occasions when radioactivity was detectable the levels were low, decayed or dispersed rapidly, and did not constitute a hazard or danger to test participants, visitors or inhabitants of the island. The dates when elevated levels were found were not associated with the detonation date of any particular UK device, but corresponded to the worldwide fall-out pattern of the time. Such global fall-out is part of background radiation to which we are all exposed.

I can also announce today that we have, in line with the Government's commitment to Open Government, and the Ministry of Defence's wish to open to public scrutiny any documents relating to the safety of test participants, declassified the yields of Christmas Island tests. The figures are contained in the environmental monitoring report for Christmas Island to which I have just referred. The corresponding figures for the Australian atmospheric nuclear weapon tests were declassified in 1985. The yield figures can be used to calculate doses from information readily available in the open literature. These calculations confirm the assertion that doses were vanishingly low at all points where participants were mustered at the instant of detonation.

I believe that this new NRPB/ICRF study confirms that there is no evidence to suggest that any cancer or other fatal disease was caused by exposure to ionising radiation from the tests.

A copy of the BMJ article and associated report will be placed in the Library of the House.