Governments and environmental advocates are promoting compact fluorescent lightbulbs (CFLs) as a way of reducing electricity use, saving money, and reducing our carbon footprint. CFLs are not a perfect technology – when turned on they take a moment to fully brighten and they contain a small amount of mercury which requires special procedures for disposal. CFLs are likely also to be a transitional technology, as more energy efficient light sources (such as LEDs) are already coming onto the market.  But CFLs are a safe and energy efficient alternative to incandescent bulbs.

It seems, however, with any new technology comes a wave of internet fearmongering, and CFLs are now a prime target. YouTube videos are circulating claiming that CFLs cause headaches, mercury toxicity, a host of symptoms from electromagnetic sensitivity, and something called “type 3 diabetes.”  Let’s take a look at the claims and the science.

Mercury in CFLs

There is a small amount of mercury in each CFL, necessary for the function of the bulb, about 4mg on average, with some newer bulbs having as little as 1.4mg. There is no exposure to mercury from using CFLs, as long as they are not broken. Even if a bulb is broken the exposure to mercury is negligible, far less than eating a tuna fish sandwich. But still, there are recommended procedures for cleaning up and disposing of a broken bulb to further minimize exposure, such as not using a vacuum, and ventilating the area. These procedures represent the cautionary principle in action, but make it easy to fearmonger about the risks of the mercury in the bulb.

According to an EPA study, only about 30% of the mercury in a CFL is released as vapor after breaking, and this occurs over a 4 day period. So a broken bulb would have to remain in a poorly ventilated area for days to reach this kind of exposure. Ventilating the room and quickly cleaning up a broken bulb is enough to reduce exposure to negligible levels.

The amount of mercury that CFLs put into the environment is actually less than the amount of mercury put into the environment by burning coal for the electricity they save. Therefore, the net effect of using CFLs is to reduce environmental mercury.

While technology that does not require the use of any toxic material is always preferred, the small amount of mercury is CFLs is not a health or environmental risk and should not discourage their use.

Ultraviolet sensitivity

Another claims is that CFLs put out more ultraviolet light and this can cause skin reactions in those who are sensitive. Those with lupus erythematosis, for example, need to avoid exposure to UV light. It remains uncertain, however, what risk, if any, is posed by indoor lighting. Published research is mostly theoretically, concluding that indoor lamps, including CFLs generally have very low levels of UV radiation, but that long term exposure could potentially lead to a cumulative effect.

However, direct comparisons show that CFLs put out less UVA than incandescent or halogen bulbs, while putting out more UVB radiation. Further, there are CFLs available that are shielded and put out the least total UV light of all options.

For the average user, UV radiation from indoor lights does not appear to be a concern. For those with skin sensitivity long term indoor exposure may be a concern, in which case they may want to use a bulb with lower UV radiation output. There seems to be more variability within bulb types than between them, but the best option is shielded CFLs.

Headaches and flicker rate

There are claims that CFLs cause headaches. These claims likely stem from two sources, the first being that headaches are common. Just about every drug in existence lists headaches as a side effect, at least in a few percent of users. This is recognized as just background noise because headaches are so common. But also, older fluorescent lights (the long tubes, not the compact variety) did have a flicker of about 60 hz, and this is noticeable by some people and could cause headaches. The newer bulbs, however, use a different technology (electronically ballasted vs magnetically ballasted) and cycle at about 10,000-40,000 hz, which is not detectable. There is also no published evidence linking use of CFLs to headaches.

Dirty electricity

The major health claim being made against CFLs, however, is that they put out “dirty electricity” which can allegedly cause a variety of health problems. There is now a video circulating on Facebook making such claims. Fear of dirty electricity goes beyond CFLs – the new bulbs are just the latest target.

Much of this seems to stem from one Canadian researcher, Dr. Magda Havas. She has dedicated her efforts to studying and warning the public about the health risks of electromagnetic radiation for years. She has become the go-to expert for the media, and her name crops up in almost every article on the subject.

This is unfortunate, because she appears to be a lone dissenting voice (some might call her a lone crank), who is often put up against the consensus of scientific opinion as if they were two equal experts. Most articles I read on the subject essentially say – some experts say electromagnetic radiation is safe, but some say that it is causing health problems, and inevitably Magda Havas is that latter expert. Meanwhile, she has published very little research, and no good research, to support her controversial claims.

For example, Havas is now talking to the media about “type 3 diabetes” as if it is a proven and accepted entity. She claims that exposure to electromagnetic radiation (including CFLs) can increase blood sugar. Her evidence is one published study, which is nothing more than a case series of four patients. Exposure to electromagnetic radiation (EMF) was often estimated (for example, assumed from working in front of a computer or using a treadmill) and not measured. There was no blinding at all to the exposure to EMF and measurement of blood sugars.

Case reports and case series are generally considered to be the weakest form of scientific medical evidence. They are one notch above anecdotes. They are used to propose new ideas for further study, but not to form conclusions. In my opinion it is irresponsible to talk to the media about the results of such research as if they demonstrate a new phenomenon. It is premature and misleading.

Regarding EMF in general, The World Health Organization recently reviewed the literature on non-ionizing radiation and found:

In the area of biological effects and medical applications of non-ionizing radiation approximately 25,000 articles have been published over the past 30 years. Despite the feeling of some people that more research needs to be done, scientific knowledge in this area is now more extensive than for most chemicals. Based on a recent in-depth review of the scientific literature, the WHO concluded that current evidence does not confirm the existence of any health consequences from exposure to low level electromagnetic fields. However, some gaps in knowledge about biological effects exist and need further research.

Unfortunately, in popular summaries of the issue I often find that this exhaustive expert review of 25,000 studies is put up against – the opinions of Magda Havas – with the conclusion that “the experts disagree” therefore, who knows?

What about CFLs specifically? They do indeed put out more EMF in certain frequencies than incandescent or halogen bulbs, but there is no evidence that this level of EMF poses any health consequences. Further, one thing is absolutely clear – EMF falls off sharply with distance. Even after a couple of feet the EMF put out by light bulbs falls from tiny by many orders of magnitude to negligible.  The EMF intensity at a distance of inches (as shown in the Facebook video) is irrelevant.

Conclusion: Dirty electricity is not based on science

The notion that EMF or dirty electricity causes a health risk, and that CFLs are a significant source of exposure, is not based upon any compelling science. Further, such claims stem mostly from a single researcher who appears to spend most of her time spreading fear about EMF than producing quality research. The media and the public should not be confused by this lone researcher on the fringe into believing that “experts disagree.”

Rather, while there is always room for more research, there is already extensive evidence for the safety of non-ionizing radiation. Special cases, like long term (>15 year) use of cell phones, where the source of EMF is held right up to the skin, are still under investigation.

Exposure from EMF in the home, from light bulbs and other sources, pose no credible health risk. The media needs to do a better job of putting claims for health risks into the proper scientific perspective.


Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also has produced two courses with The Great Courses, and published a book on critical thinking - also called The Skeptics Guide to the Universe.