Electromagnetic fields (EMF) are created by anything carrying electrical current, most notably high tension power lines. There is inconclusive evidence that there may be health risks associated with long-term exposure to EMF.
Luckily, the intensity of the EMF depends on the proximity to the power source. Careful measurements often demonstrate that the EMF created in a home by an electric stove is greater than the EMF created by overhead power lines on the adjoining property.
Measurements can be taken on your behalf if this issue concerns you. The power company sometimes will do this as a free service.