Exposure guidelines for low-frequency electric and magnetic fields: report from the Brussels workshop.

The EMF Exposure Guidelines Science Workshop was held to evaluate the information base for guidelines for electric and magnetic field exposures at extremely low frequencies, to identify research needs, and to discuss how best to apply scientific knowledge in developing exposure recommendations. Although the existing guideline values are based on electrostimulation of nerve and muscle tissues, guidelines must also consider controversial studies of potential health effects from chronic exposures at environmental levels that are far too weak to cause electrostimulation. The size of the safety factor applied in specifying exposure limits reflects a variety of factors that introduce uncertainties. These include confidence in existing dose-effect relationships, population diversity, the reliability and precision of techniques to control over-exposure, and completeness of the information base, particularly regarding long-term effects. Specific research questions that can change the level of uncertainty meaningfully were identified in these areas: biophysical mechanisms of electrostimulation; the range of thresholds throughout exposed populations; cancer causation in children and adults, including a possible role for contact currents; cognitive, behavioral, and physiological effects on the central nervous system; improved dosimetry; and better understanding of electromagnetic interference with implanted biomedical devices such as pacemakers, defibrillators, and physiological monitors. This report introduces ten papers from the workshop that address these and related topics in detail.