The internal electric current or power levels that a human is likely to encounter in a typical electromagnetic field environment are calculated. At 60 Hz, a reasonable value for maximum permissible exposure is an internal current density of 1 microA cm(-2). At this frequency, a 600 V m(-1) electric field results in a current density of 0.0002 microA cm(-2), while a 200 microT magnetic field results in 0.6 microA cm(-2). This should be compared with an action potential, which is associated with a current density of 800 microA cm(-2). The ANSI/IEEE C95.1-1991 standards, whose frequency range is 3 kHz to 300 GHz, are examined. Epidemiological studies are briefly considered. The conclusion is that it is highly unlikely that there is a link between electromagnetic fields and cancer.