Concerning guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (1 Hz-100 khz).

1. In the introduction the notation “mHz” is used when “MHz” was intended; 2. The minimum threshold for the induction of magnetophosphenes is given as 5 mT at 20 Hz without justification. In one of the few well-controlled quantitative studies of magneto-phosphenes (Lövsund et al. 1980), the limit is given as 10–12 mT for a sinusoidal exposure in the range 20–30 Hz. Recently, Glover et al. (2007) have reported a magnetophosphene threshold of around 1.5 Ts 1 for a single pulse of duration 50 ms, consistent with the earlier values; and 3. In Table 3 containing the Reference Levels for occupational exposure, the magnetic flux density value in the range 1–8 Hz is given as 0.2/f, which is inconsistent with the value of magnetic field strength. By inference the correct value should be 0.2/f.