An expert scientific working group of the Monographs Programme of the International Agency for Research on Cancer (IARC) has concluded its review of health effects of static and extremely low frequency (ELF) electric and magnetic fields. Such fields include the earth's magnetic field, and also originate from electrical power transmission lines, electrical wiring in buildings, and electric appliances. Magnetic fields are measured in units of microTesla; the earth's static magnetic field, to which everyone is exposed, varies from 25 microTesla at the equator to 65 microTesla at the poles. Most research on health effects has been done on ELF magnetic fields with frequencies of 50 or 60 Hz.
Reports were first published in 1979 that childhood cancer might be
associated with exposures to residential ELF fields. Numerous studies
in many countries have been undertaken since then of possible increased
cancer risks in children and adults from ELF magnetic field exposures.
Special attention has focussed on leukaemia and on brain tumours, which
early reports had suggested might be increased. IARC has now concluded
that ELF magnetic fields are possibly carcinogenic to humans, based
on consistent statistical associations of high level residential magnetic
fields with a doubling of risk of childhood leukaemia. Children who
are exposed to residential ELF magnetic fields less than 0.4 microTesla
have no increased risk for leukaemia. Because of insufficient data,
static magnetic fields and static and extremely low frequency electric
fields could not be classified as to carcinogenic risk to humans.
However, pooled analyses of data from a number of well-conducted studies
show a fairly consistent statistical association between a doubling
of risk of childhood leukaemia and power-frequency (50 or 60 Hz) residential
ELF magnetic field strengths above 0.4 microTesla. In contrast, no consistent
evidence was found that childhood exposures to ELF electric or magnetic
fields are associated with brain tumours or any other kinds of solid
tumours. No consistent evidence was found that residential or occupational
exposures of adults to ELF magnetic fields increase risk for any kind
Studies in experimental animals have not shown a consistent carcinogenic
or co-carcinogenic effects of exposures to ELF magnetic fields, and
no scientific explanation has been established for the observed association
of increased childhood leukaemia risk with increasing residential ELF
magnetic field exposure.
Health effects of radiofrequency electromagnetic fields, which are produced
by such sources as radio and television transmission towers, portable
telephones, and radar, were not evaluated by the IARC working group.
These exposures will be reviewed by the IARC Monographs Programme when
research that is currently in progress has been published, most likely
For further details of the Monographs evaluation, consult http://monographs.iarc.fr, under "Agents most recently evaluated," or inquire by e-mail to
For further details of current research at IARC on electric and magnetic fields, inquire by e-mail to
For more general information, please contact Dr Nicolas Gaudin, Chief, IARC Communications (