These will develop into a tumor only following the introduction of another chemical or physical agent, known as a cancer promotor. Cancer promoters cannot by themselves cause cancer. They may, however, act on initiated cells to promote cancer development. But it is important to keep the potential risk in perspective. As one observer has noted, even if there should be a doubling of the risk of a very rare event, it would still be a very rare event.
Cancer accounts for about a quarter of all deaths in American adults.
This proportion has not increased since electricity came into general use. EMF experiments using humans have shown effects on heart rate and reaction time from exposure to strong fields, but these appear to be reversible. There is no evidence of a lasting effect in either case. Also, many of the laboratory tests indicating possible effects on animals were conducted at field strengths far above those found in the everyday use of electrical equipment, wiring or appliances. Even so, most animal studies have shown no differences between animals and tissues exposed to EMF and those not exposed.