Professor Henshaw responds to the NRPB proposals for public exposure to electric and magnetic fields (EMFs) from high voltage powerlines and the electricity supply generally, saying that in light of the considerable evidence of adverse health effects of exposure associated with exposure to such fields, the proposals should go much further.

Respected international bodies, including the International Agency for Research on Cancer have accepted that epidemiological studies have shown a doubling of the risk of childhood leukaemia associated with magnetic fields above 0.4 microtesla (µT).  This level is below that typically found near some fixed sources such as powerlines.  In addition, a major report issued by the California Health Department in 2002 also indicated an increased risk of adult brain cancer, miscarriage and possibly other illness associated with exposure to EMFs from the electricity supply.

The proposal to limit public exposure to magnetic fields to 100 µT, 250 times higher than the 0.4 µT where a doubling of the risk childhood leukaemia is acknowledged, looks ridiculous when viewed alongside the well established practice for chemical carcinogens where levels are set at least 1,000 times below that where evidence of harmful effects have been found.

In the case of new fixed installations such as powerlines and electricity substations, some countries took action many years ago to severely limit public exposure.  Sweden introduced a 0.2 µT limit in 1996, Switzerland 1.0 µT in 1999 and three Italian regions 0.2 µT in 2000.  Such steps underline the need to act now in introducing a strict limit of say 0.2 µT in the case of all new fixed installations such as powerlines and sub-stations.

Professor Henshaw called upon the NRPB to follow the example of other countries and said: "If such precaution is good enough for these countries why is it not good enough for the UK?  There is now good scientific understanding of the way in which exposure to magnetic fields may increase the risk of a range of illnesses, and further evidence is continuing to emerge.

"In particular, a body of studies in human populations have reported that magnetic fields at even low levels can disrupt the production in the pineal gland of the important hormone and natural anti-cancer agent melatonin. This may explain why studies have shown that exposure to magnetic fields may lead to increased risk of childhood leukaemia, adult brain cancer, miscarriage and depression."