@ltecato It's possible. A hearing aid with a telecoil may not be able to tell the difference between desired and unwanted electromagnetic (EM) waves since its designed to use this type of signal. I have to imagine that there is filtering of any EM outside of the audio frequency range though. Products have to pass EM testing when they're designed. Depending on the product, the amount of allowable EM may be different. Filters are used to limit the amount of EM emitted. It's rare that the filter components go bad, but it is possible. I have telecoils in my aids and if I have them enabled, I pick up interference from the security devices that are used in stores and libraries. It doesn't cause issues for me since it only happens within inches of the security devices. I sometimes hear the buzz from the power company wires when I'm in my car.
Tony in Michigan