Power lines and cancer

:: Power lines and cancer

Power lines produce extremely low frequency (ELF) electromagnetic fields in range of 50 Hz to 60 Hz. Electric fields do not reach people inside houses, but magnetic fields go through most materials and cause an additional exposure higher than the typical background field (about 0.1 µT) up to a distance roughly 50 metres from the power line, depending on the voltage and wire configuration. Health effects on humans related to this non-ionising type of radiation have been investigated in epidemiological studies for over two decades.

The first report of an association between childhood cancer and power line exposure was published in 1979, and after that at least 24 studies on the same topic have been published. There have been two meta-analyses published lately that both suggest a significant 1.7–2.0-fold excess of childhood leukaemia in the extremely rarely existing fields above 0.3 or 0.4 µT. The excess may be attributable to patient selection and publication bias, and a plausible biological mechanism is not known.

It appears on the basis of studies with large numbers of cancer cases that there is no excess risk of cancer among adults living close to power lines, but the possibility of an association between some cancers and exposures to ELF magnetic fields is suggested by some occupational studies.

IARC classified ELF magnetic fields as possibly carcinogenic to humans (Group 2B) in its evaluation[14], while ELF electric fields were considered not to be classifiable as to their carcinogenicity to humans (Group 3). This evaluation only considers the likelihood of an association, but does not take into account the magnitude of the possible risk to individuals nor the population attributable risk. The results of epidemiological studies suggest that appreciable magnetic field effects, if any, are concentrated among relatively high and uncommon exposures.