I spoke to someone this weekend who was adamant that dimmer switches in households "cause" cancer. His claim was that since dimmer switches work by rapidly modulating the voltage to the lights they emit rapidly changing electromagnetic waves that are, I guess, more dangerous than a steady electromagnetic wave.

This sounds like physics pseudoscience bunk to me, but I was unable to find any articles online either confirming or debunking this claim.

  • This is just another variant of the Dirty Electricity claim, which we have addressed before.
    – Oddthinking
    Commented May 29, 2012 at 4:11
  • This is specifically about varying the wavelength. Commented May 29, 2012 at 5:22
  • @Christopher - Which is essentially the definition of dirty electricity. I am skeptical that the dimmer switches cause dirty electricity but the claim boils down to the dupilcate.
    – Chad
    Commented May 30, 2012 at 19:56
  • Can you explain what you mean by "rapidly changing electromagnetic wave" and "steady electromagnetic wave?" Also, what do you mean by "rapidly modulating the voltage?"
    – oosterwal
    Commented Jun 14, 2012 at 6:47

1 Answer 1


The answer is no.

From pcbheaven.com,

A dimmer is a device that is originally created to control the brightness of lamps. This is done by altering the total power delivered to the lamp and thus the brightness.

To clarify the question, do fluctuations in the amplitude (power) of the electromagnetic waves produced from a light source cause cancer?

lumec.com reports a study in specific to unnatural light patterns on the human body:

Where it becomes an even more important concern is that it has been known for over a hundred years that cell division inside the body follows a circadian rhythm, we have just explained that the circadian rhythm is affected by light, and we also know that damage to cell division is characteristic of cancer. You do the math…

Studies have shown that mice, when exposed to unnatural patterns of artificial light, developed certain problems related to their cell division and also to the transcription of many genes. In other words, they were in for some major health problems on the long run, if they remained exposed to that type of light – and so would we.

As well as an article from The Daily Star:

Blask and his colleagues have been recognized for research on the cancer-stimulatory effects of light at night through the suppression of melatonin, a key hormone, according to a Bassett Healthcare media release. A study in 2005 by Blask and his colleagues provided evidence that light at night promotes growth of human breast cancer. The study also provided insight into why breast cancer is increasing rapidly in developing countries and industrialized societies.

It seems that evidence is leaning heavily toward the fact that either A) our natural cycles rely on light at specific times, or B) the lack of production of melatonin in the brain has adverse and sometimes cancerous effects.

The information provided against artificial light is almost strictly based on non-direct processes in the body - not the amount of energy produced by the light source.

Our bodies are constantly subjected to all different areas of the electromagnetic spectrum and radiation:

For comparison, the average 'background' dose of natural radiation received by a person per day, based on 2000 UNSCEAR estimate, makes BRET 6.6 μSv (660 μrem). However local exposures vary, with the yearly average in the US being around 3.6 mSv (360 mrem)

To clarify one point, light is essentially radiation as being part of the electromagnetic spectrum. This consists of radio waves, micro waves, wireless devices, visible light, x-rays, etc. If varying the voltage that goes through a light bulb has anything to do with cancer, every human on Earth would have cancer after being exposed to huge amounts of every type of wavelength known and unknown to man every day.

  • Your answer does not even mention dimmers. Please address the OP question directly.
    – Sklivvz
    Commented May 29, 2012 at 6:44
  • @Sklivvz, the main point is fluctuating voltages through a light source, a dimmer switch is merely an example. Regardless, I added some information to connect it all together. Commented May 29, 2012 at 7:56
  • @Christopher: My reading of the claim is not "dimmers make lightbulbs into carcinogenic radiation sources", it is that "dimmers, themselves, are carcinogenic radiation sources." i.e. don't stand next to the dimmer switch, rather than don't look at the light.
    – Oddthinking
    Commented May 29, 2012 at 8:13
  • 1
    @Oddthinking, I can see how you could extrapolate that. Making the distinction between 'rapidly changing' and 'steady' electromagnetic waves implies the light, atleast in my opinion. I suppose this requires some clarification from OP. Commented May 29, 2012 at 8:45

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .