Abstract
Epidemiological studies since 1979 have raised some medical and much public concern that low frequency electromagnetic fields, such as those of power‐lines and in domestic and industrial electrical wiring, may have harmful biological effects. These studies are generally inconsistent, inconclusive, and difficult to replicate. Identifying biological mechanisms by which such harmful effects may occur has proved difficult, although there are several new and promising approaches. In epidemiological and laboratory studies’ much greater co‐ordination and standardization is needed if greater scientific knowledge of these phenomena, as opposed to mere diverse speculation, is to be achieved.