1. The Sunday Times carried a front page article 4.3.01 headlined "Pylons are a cancer risk - official" and subtitled "Top scientists establish link". While this slightly overstates the small print of what the NRPB will say, in its key report due tomorrow, it is a big step forward in recognising an association of increased childhood leukaemia with exposure to fields from power lines.
2. Technically, an "association" means that two things tend, statistically, to occur together. It does not mean that one causes the other, or vice versa. Officially there is still doubt about cause, but recognition of the association has been long overdue. Landmark studies have accumulated over recent years, culminating in the pooled international studies of Greenland et al [Epidemiology 11: 624-634, 2000] and Ahlbom et al [Brit J Cancer 83(5): 692-698, 2000] which confirmed the association with childhood leukaemia for exposures above 0.4(T.
3. Establishing cause requires, principally, a plausible biological mechanism. Cancer is complex and multifactorial. It is not surprising that precise mechanisms are not known. But there are at least three reasonable hypotheses: the melatonin hypothesis (that nocturnal production of melatonin, an anti-carcinogen, in the pineal gland is suppressed by the magnetic fields), the free radical hypothesis (that the magnetic fields release a chain of biochemical reactions promoting carcinogenic free radicals) and the charged aerosol hypothesis (that powerlines create charged aerosol particles which carry carcinogenic contaminants and which are deposited on the skin and lungs). This combination ought to be recognised as a plausible basis for likely cause, but is not.
4. NRPB's recognition of the association, albeit rather late and scheduled when the budget will dominate publicity, should change the landscape. REVOLT calls on National Grid to abandon the 400kV Picton- Shipton line. We do not oppose the Lackenby-Picton line - there is now a formal condition for the removal of the 275kV Lackenby-Norton line near many houses in Teesside. REVOLT welcomes the removal of that line. But we do call for the new Lackenby-Picton line to be diverted to avoid houses at Eston and Nunthorpe. It should then be teed in to the existing 400kV line at Picton, and not continue to Shipton.
5. National Grid has sheltered behind NRPB advice in the past. When local authorities have tried to adopt precautionary policies in their local plans, e.g. for a cordon sanitaire along powerlines to restrict building houses or schools, National Grid has intervened with formal objections, knowing the government will back them in inquiries and appeal decisions. Now the local authorities should be allowed more discretion to adopt precautionary policies.
6. Over the last few days I have been discussing these developments with Prof. Henshaw and others involved, and with the Sunday Times and doing media interviews today. Peter Edmonds of the NFU Northallerton has also been busy with media interviews. I have ordered the full NRPB report, which comes out tomorrow and will not arrive here until Wednesday. It is not on the internet, so I will have to wait for the paper version to study it.
7. The NRPB is expected to argue, as did Professor Colin Blakemore (NRPB Advisory Group on Non-Ionising Radiation member) on BBC1 today, that few people in the UK are exposed at the levels associated with cancer! Well, the principle is the same, they shouldn't have risky exposures forced on them - even one child with leukaemia is too many, as Linda Breckon comments. In any event NGC declares field levels of 40(T under powerlines, and I have often measured fields in houses near powerlines well above the levels of association.