The current guideline for exposure to radiofrequency radiation (RFR) of 0.4 W/kg may have inadvertently been set to high. The guideline is based on the rate of RFR absorption normalized with respect to body mass. Based primarily on data for work stoppage in the rat, the 0.4 W/kg guideline was calculated by the dividing the 4.0 W/kg dose by a safety factor of 10. However, if the RFR dose in the rat had been normalized with respect to surface area rather than body mass, the exposure guideline would be 2.3 W/sq m which translates, for a 80 kg adult, to an SAR of approximately 0.06 W/kg. Thus, the current RF exposure guideline may be several fold greater than originally intended.