Answer to Question #10952 Submitted to "Ask the Experts"

Category: Micro/Radio Waves, Radar & Powerlines — Microwaves and Radiofrequency

The following question was answered by an expert in the appropriate field:


I recently moved my treadmill to my bedroom. Each morning I run on it for 15 minutes. When I'm done with my workout, I turn off the machine and unplug it from the outlet. Do I need to be worried about any dirty electricity or anything associated with EMF (electric and magnetic fields) staying in my room hours after I finish?


I will answer your question in three parts:

  1. EMF staying in my room? When you turn an appliance off there is no longer any current flowing and hence no EMF associated with that appliance. There is still the possibility that there are ground loops or other small currents flowing in house lines, but EMF from those sources should be minimal compared to when appliances are actually running.
  2. Should you be worried? No. After years of research and studies by many reputable organizations, there is still no convincing evidence that low-level EMF from household wiring or appliances causes adverse health effects. Please see some of the material written by the Health Physics Society and other credible organizations (, or There is convincing evidence that high-level EMF can cause adverse health effects, and there are adequate safety standards in place to prevent such effects. High-level EMF are produced by industrial and medical sources, not by household wiring and appliances.
  3. Dirty electricity? AC (alternating current) electric-supply current contains electrical noise and harmonics sometimes referred to as "dirty electricity" because it is not a pure 60 Hz sine wave. However, answer #2 above still applies.

Gary H. Zeman, ScD, CHP
HPS ATE Nonionizing Radiation Topic Editor

Answer posted on 7 April 2014. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.