There are magnetic fields, and there is electromagnetic radiation. You'll contend with more problems from magnetic fields (mains hum), than from electromagnetic waves.
In order for electromagnetic waves to harm your circuitry, they would need to be extremely powerful at the source.
Something on the order of a microwave beam, or radar transmitter, or radio broadcast antenna, or EMP.
I'm under the impression that the post is asking for susceptibility tests in actual EMC regulations (e.g. IEC 1000-4-3) rather than discussing a broad idea of electromagnetic effects.
The question is however hard to answer without any information about the kind of device.