The use of implanted medical devices that address a wide range of health conditions is rapidly expanding. These implanted devices include: Cochlear implants, drug dispensing pumps, cardiac pacemakers, defibrillators and other devices. Although these devices are designed to withstand interference from external radio frequency, electric and magnetic fields, interference can occur which may affect the operation of these devices and pose a health risk. An inventive personal, body-wearable electric field, radio frequency, and three-axis magnetic field monitoring device detects the ambient radio frequency, electric and magnetic fields and warns the wearer when any of these field measurements exceeds a safe level.