Enhancement of Low-Level Magnetic Fields by Ferromagnetic Objects

Abstract

Abstract Low-intensity magnetic fields, generally considered to be safe from a bioeffects standpoint, may cause problems to workers who wear cardiac pacemakers. Low-intensity magnetic fields can interfere with pacemaker circuitry and can cause cardiac arrythmias in some pacemaker wearers. This interference can occur at field levels above approximately 14 Gauss (1.4 milliTesla). In research presented in this article, magnetic field “enhancement” by ferromagnetic objects (nonmagnetic metallic objects containing iron) was investigated. It was demonstrated that ferromagnetic objects, if placed in a magnetic field, can increase local magnetic field intensities by an order of magnitude. Ferromagnetic enhancement of magnetic fields can increase apparently safe magnetic fields (below the proposed Threshold Limit Value of 10 Gauss or 1.0 mTesla) to levels which are unsafe for some cardiac pacemaker wearers. Because of these risks, the authors recommend posting warning signs in workplaces where magnetic fields are ...