Power Stands Charged
Journalist: Anjana Ahuja
March 03, 2003
Are electromagnetic fields causing women to miscarry, triggering childhood
leukaemias, and even driving some people to suicide? As new studies emerge,
the experts are divided
You can't see, smell, hear or feel them, but they surround you at work and
at home. And, according to some scientists, the electromagnetic fields given
off by electrical appliances, house wiring, computers or overhead power
lines are far from innocuous - they constitute an invisible menace eating
away at our health and are responsible for such diverse ills as childhood
leukaemias, brain cancers, miscarriage, depression and even suicide.
Last year, the National Radiological Protection Board (NRPB), the
government-funded organisation which sets safety limits on exposure,
concluded that high electromagnetic fields (EMFs) might double the risk of
childhood leukaemia, and was probably responsible for an additional two
deaths from the disease each year. Now a massive report from researchers in
the United States has cast the net of doubt much wider. The report,
conducted by three senior figures at the California Department of Health
Services, concluded that the authors "are inclined to believe that EMFs can
cause some degree of increased risk of childhood leukaemia, adult brain
cancer, Lou Gehrig's disease (a degenerative neurological condition similar
to motor neurone disease) and miscarriage".
The link to miscarriage was especially dramatic - as many as one in 20
pregnancies may end prematurely due to EMF exposure, the report said.
Whether by coincidence or serendipity, the NRPB, which is independent of the
power industry, will shortly issue a discussion document on whether action
The miscarriage link is controversial - both the NRPB and the Electricity
Association, which speaks for power companies, say the studies on this were
But Denis Henshaw, a professor of physics at Bristol University, who argues
that power lines can make people sick, says that the new findings on
miscarriage turn this into a major public health issue.
"We're talking about an absolute extra risk of miscarriage of 5 to 10 per
cent, which is considerable," Henshaw says. "The power industry has always
argued that even if there was an increased risk of childhood leukaemias,
they are still very rare, and so it wasn't a public health matter. This is a
much bigger can of worms." Henshaw believes that EMFs are responsible for
skin cancers, lung cancers, depression and around 60 suicides a year.
The authors of the American report, which took ten years to complete, cost
$7 million (£4.4 million) and runs to 400 pages, couldn't rule out links
with suicide or adult leukaemia. All three scientists were "close to the
dividing line between believing and not believing" that EMFs put a person at
increased risk of these. They did not believe that EMFs were implicated in
birth defects, other cancers, heart disease, Alzheimer's disease or
depression. The report did not look at the EMFs from mobile phone masts.
Henshaw has hailed the report, the final draft of which was released on the
internet without announcement last summer, as "groundbreaking". He says:
"(The report) is unprecedented in its depth. The power industry has tried to
ignore it, but it's so substantive that people can't really complain about
it. Importantly, it's also been independent from industry pressure. It
should wake people up."
Henshaw argues that the NRPB should follow the examples of Switzerland and
Sweden in reducing the maximum safe exposure levels. The doubling of
childhood leukaemias was seen at levels of 0.4 millionths of a Tesla (0.4
microTesla). The safe limit is set at 4,000 times that, at 1600 microTesla.
Four years ago, Switzerland dropped the maximum to just 1 microTesla. To
drop the limits any less dramatically, Henshaw comments, "would be as
irrelevant as reducing the speed limit on the motorway from 1,000mph to
500mph". He also believes that houses should no longer be built near power
lines or substations, and that cables should be buried underground.
Dr Michael Clark, scientific spokesman for the NRPB, says the Californian
report "can't be dismissed but, because it is a review of existing work
rather than new research, it doesn't substantially change anything". He
cautions against being too prescriptive about exposure levels because the
conveniences of modern life might be as much to blame as pylons and
powerlines. "Hairdryers produce large fields, as do car engines, but can we
really tell people not to drive their cars?"
While someone standing directly beneath a power line might experience a
magnetic field of 40 microTesla, a hairdryer or electric razor can produce
1000 microTesla. However, Dr John Swanson, scientific adviser on EMFs to the
Electricity Association, says that these high exposures come in short
bursts, and holding a hairdryer even a few inches away from the head cuts
the level to about 100 microTesla.
Clark says that because many factors probably contribute to miscarriage, it
is vital to be sure that the role played by EMFs is genuine.
The NRPB has appointed Sir Richard Doll, the epidemiologist who famously
spotted the association between smoking and lung cancer, to review all the
evidence, including that on miscarriage. Under his guidance, the NRPB
believes that there is "(no) substantial evidence of increased risk of
miscarriage attributable to exposure to above-average magnetic fields" and
therefore no regulatory action is called for.
Doll's scepticism is shared by Swanson, who says: "The miscarriage studies
are sufficiently flawed for me to be wary. For example, the participation
rate was only about 39 per cent of the women approached, and most
epidemiologists would look for a rate of at least 50 per cent. The questions
raised are valid but these studies don't answer them.
"I think the California report is wrong. Their conclusions are out of line
with most other reputable research groups around the world."
What is really needed to resolve the issue is harder statistical evidence,
or a killer fact - a convincing, provable scientific theory of how EMFs can
physically damage the body. Such a theory would not only settle the
uncertainty, but would also pave the way for legal action. Lawyers such as
Martyn Day, whose London firm Leigh & Day is in touch with potential
litigants, say that the California report is an important new weapon in the
battle. "It's a significant new piece of evidence which has pushed me back
to the edge," he says.
"But I could see the courts being very nervous about this one. There is
evidence that EMFs affect molecules, but not enough to break them apart. And
it is always possible that it is something else, rather than the EMF, that's
causing the damage." And so, in the midst of blurred, ambiguous statistics,
the controversy lingers. People living in the shadow of power stations
continue to pile up anecdotal evidence of ill-health, miscarriage and
suicide. And, in the absence of hard figures, scientists remain reluctant to
believe that the power lines that lattice the landscape could damage unborn
babies and make people take their own lives.