THE health dangers from nuclear radiation have been oversold, stopping governments from fully exploiting nuclear power as a weapon against climate change, argues a professor of physics at Oxford University.

Wade Allison does not question the dangers of high levels of radiation but says that, contrary to scientific wisdom, low levels of radiation can be easily tolerated by the human body.

Most scientists who have responded disagreed with Allison's conclusions, but his comments have highlighted the lack of understanding of how the body deals with low doses of radiation, a crucial issue given it is increasingly used in modern medical procedures such as scanning and cancer treatment.

Nuclear crises, from the bombing of Hiroshima and Nagasaki to the meltdown of a nuclear reactor at Chernobyl, have created widespread fear and distrust of nuclear power, and global pressure to keep radiation at the lowest possible level, according to Allison, a particle physicist who makes his arguments in a self-published book, Radiation and Reason. He says long-term data on the health of survivors of the atomic bombs have demonstrated how good the human body is at protecting itself from radiological and chemical attack.

“The ability to repair damage and replace cells, we discovered in the last 50 years, show how radiation doesn't cause damage except under extreme circumstances,” he says. “The radiation that a patient gets in one day from a course of radiotherapy treatment, it would take a million hours of exposure for someone standing in the radioactive waste hall of Sellafield. And, if you have radiotherapy, it goes on for several weeks.”

Ionising radiation, the type from nuclear reactions, can break strands of DNA in cells and these can make a cell cancerous unless the body's machinery can fix the damage. Scientists have used data from Hiroshima and Nagasaki, plus that from experiments on animals and cell cultures, to create a measure of how much damage is caused by high levels of radiation. This has then been extrapolated back, in a straight line, to estimate the potential damage from low levels of radiation to create what is called the linear non-threshold (LNT) model.

“The problem with a lot of these discussions is that you eventually get to the point where you don't have any more data,” said Prof Gillies McKenna of Oxford University, Cancer Research UK's expert on radiation oncology. Since the end of the Second World War, scientists have worked on the basis that there is no dose of radiation so low that it is not dangerous. Allison, however, believes there is a threshold below which any radiation exposure is fully repaired by the body — but this is a view mainstream scientists disagree with.

Where McKenna and other scientists do agree with Allison is that fear of radiation is a problem. McKenna's expertise is in the use of radiation to kill cancer cells. “People become so fearful of radiation that they avoid diagnostic tests that might save their lives or avoid radiotherapy when they have cancer that is much more likely to kill them than exposure to radiation. He [Allison] is right that it has become a little bit hysterical.”

Some areas, such as Devon and Cornwall in southwest England, have naturally high levels of radiation in the rock, and yet they do not have a high incidence of cancer. “It would suggest to me that we can tolerate relatively higher doses of radiation, unless you add things on top like smoking,” said McKenna.

Nothing has generated quite as much cancer concern in the UK as Sellafield power station in Cumbria, northern England. Concern about radiation leaks at the plant, known as Windscale when it was commissioned in 1956, grew over the years until in 1983, Yorkshire Television produced a documentary called The Nuclear Laundry, suggesting low-level radiation emissions posed a risk. In the 1990s clusters of childhood leukaemia cases were identified near the site.

— The Guardian, London