A Town Hall About The Health Risks of 5G Cell Phone Technology

5G Town Hall
Rochester, Michigan
November 7, 2019.

Yesterday I participated in a town hall meeting in Rochester, Michigan to discuss the new 5G cell phone technology. I was invited to attend in part because of my contributions to the book Intermediate Physics for Medicine and Biology, which discusses the health risks of electromagnetic fields.

When preparing for the event, I created a list of frequently asked questions (well, these were the questions I thought people would ask). Not wanting to waste this effort, I reproduce my FAQ below.

The event was....interesting. I was impressed by the passion of these concerned citizens, who packed a large room on a cold Thursday evening and for over two hours asked questions and voiced their opinions (mostly voiced their opinions). I’ve taught plenty of apathetic 20-something-year-olds who don’t engage with the lecture or challenge what I say, so I found this feisty crowd refreshing. Unfortunately, I was not convinced by their claims of dire health effects from 5G technology, and they were not convinced by me. The most disturbing moment was when I said something along the lines of “if you want to know more about the risks of cancer, consult the National Cancer Institute” and the response was a chorus of “No, No, No!” Goodness, if we can’t trust the National Cancer Institute to understand cancer, who can we trust? But no one threw a tomato at me, so I’ll call the evening a success. The FAQ below summarizes my view on this matter.

FAQ: 5G Cell Phone Health Effects

What is 5G?

5G is the fifth generation of technology for cell phones. It uses higher frequencies of electromagnetic radiation than 4G technology (up to 300 GHz, with a wave length of 1 mm).

What does IPMB say about the health risks from cell phones?

Section 9.10.5 of Intermediate Physics for Medicine and Biology addresses possible health risks from microwaves, mobile phones, and wi-fi. Russ Hobbie and I cite a 2005 review by John Moulder, Ken Foster, and their colleagues, which concludes that “Overall, a weight-of-evidence evaluation shows that the current evidence for a causal association between cancer and exposure to RF [radiofrequency] energy is weak and unconvincing.” We also cite “an exhaustive (390 page) report…by the International Committee on Non-Ionizing Radiation Protection (Vecchia et al. 2009)” that reaches a similar conclusion. Next we write that “Sheppard et al. (2008) evaluated all the proposed mechanisms for radio-frequency interactions with biological molecules and processes…[and conclude that] the principal mechanism for biological effects, and the only well-established mechanism, is the heating of tissues.” Finally, “Foster and Moulder (2013) reviewed the current state of research [on the health effects of wi-fi, and conclude that the evidence provides] ‘no basis to anticipate any biological effects.’”

The 2013 review by Foster and Moulder summarizes my opinion on this topic.

“Impossibility” arguments are difficult to sustain in biology; but the lack of a generally-accepted mechanism by which low-level (below ICNIRP and IEEE limits) RF fields in the GHz frequency range could produce biological effects, after many years of sustained efforts to uncover such mechanisms, makes it increasingly unlikely that any mechanism will be found.

What have Foster and Moulder said lately about health risks from wi-fi?

Ken Foster and John Moulder are experts on the interaction of electromagnetic radiation with the body. They are skeptical about many claims of health risks caused by power-line, cell-phone, and wi-fi radiation. Both are now emeritus professors; Foster at the University of Pennsylvania and Moulder at the University of Wisconsin. Intermediate Physics for Medicine and Biology cites Foster and Moulder several times, but the 5th edition of IPMB was published in 2015. What have they said lately?

Foster published a post two months ago in a Scientific American blog looking specifically at 5G technology and health risks. His conclusion: “So far, at least, there’s little evidence of danger.”

The most interesting development is a critique of Foster and Moulder’s 2013 review by Martin Pall, an emeritus professor at Washington State University. He concludes that “there are seven repeatedly found Wi-Fi effects which have also been shown to be caused by other similar EMF [electromagnetic field] exposures. Each of the seven should be considered, therefore, as established effects of Wi-Fi.” Pall’s central hypothesis is that cell phone radiation affects calcium ion channels, which if true could trigger a cascade of biological effects. In a rebuttal, Foster and Moulder (2018) write

Pall (2018) criticizes our 5-year-old review of studies related to Wi-Fi and health (Foster and Moulder 2013). We respond to his critique, and also note weaknesses in his selection and interpretation of studies on biological and health effects of Wi-Fi type signals...

Having examined the additional papers that Pall cites, we reaffirm our earlier conclusion: a number of studies have reported bioeffects of Wi-Fi exposures, but technical limitations make many of them difficult to interpret and artifacts cannot be excluded. We are not aware of any health-agency warnings about health risks of Wi-Fi technology. Despite some level of public controversy and an ongoing stream of reports of highly variable quality of biological effects of RF energy (e.g. articles in a recent special issue of the Journal of Chemical Neuroanatomy, Volume 75, 2016) health agencies consistently conclude that there are no proven hazards from exposure to RF fields within current exposure limits (even as they consistently call for more research).

My advice is to read the review, the critique, and the rebuttal, and then draw your own conclusion. You may find many of the technical details difficult to understand (I do), but you will better appreciate the complexity if these issues, and the difficulty in drawing definite conclusions from imperfect data. I don’t agree with Pall’s claims.

What does Bob Park have to say about the health risks from cell phones?

Robert Park is an emeritus professor of physics at the University of Maryland, and was the director of public information at the Washington office of the American Physical Society. He is the author of Voodoo Science, and wrote a weekly column titled “What’s New” debunking pseudoscience. His health has not allowed him to contribute to the recent discussion about the risks of cell phones and 5G technology (and, oh, how we miss him). Here’s what he wrote in “What’s New” on Sunday, May 6, 2012.

1. ALBERT WHO? DEAD PHYSICIST DISPELS MOBILE-PHONE MYTH. According to news reports last week: "There is still no evidence of harm to health from mobile-phone technologies," or other wireless devices such as Wi-Fi. A study for the UK's Health Protection Agency (HPA) is said to be the most complete review yet and new evidence is still being examined, according to Professor Anthony Swerdlow of the Institute of Cancer Research, who chaired the study. I once had a rubber stamp made that said: “More research is needed,” since its found at the end of every science paper. The unanswered question is why anyone thought microwave radiation might be a cancer agent in the first place? Cancer is linked to the formation of mutant strands of DNA. More than 100 years ago in his 1905 paper on the photoelectric effect, Albert Einstein predicted an abrupt threshold for photoemission at about 5 eV, just above the lovely blue limit of the visible spectrum, demonstrating wave-particle duality. He was awarded the 1923 Physics Nobel Prize [actually, Einstein received the Nobel Prize in 1921, and Robert Millikan received it in 1923, in part for his experimental work on the photoelectric effect]. Its also the threshold for the emission of invisible ultraviolet radiation that causes hideous skin cancers. The cancer threshold, is therefore, 1 million times higher than the microwaves band. The same enormous mistake was made in the 1980s when epidemiologists falsely warned that exposure to power line emission can cause cancer. Power lines abruptly stopped causing cancer in 1997 after the U.S. National Cancer Institute conducted a better study. Its painful to witness this sad history being replayed with mobile-phone radiation. Aside: My apologies to regular readers who have heard this 20 times before, but it has not gotten through to everyone.

Park’s argument remains as true now as eight years ago, except that a 300 GHz photon has an energy of one-thousandth of an electron volt, which is “only” a few thousand times less than the threshold for photoemission or UV skin cancer (and is about 25 times smaller than thermal energy, 0.025 eV). The possibility of DNA damage—the underlying cause of cancer—remains extraordinarily remote, but not as ridiculously remote as it was for cell phone technology ten years ago.

Electromagnetic radiation is considered a possible carcinogen. What’s that mean?

Something that is “possibly carcinogenic to humans” doesn’t probably cause cancer. It probably doesn’t cause cancer, but we can’t say for certain. RF radiation was not placed into two more threatening categories: “probably carcinogenic to humans” and “carcinogenic to humans.”

The website Science-Based Medicine states that

Despite the negative evidence to date, in 2011, the International Agency for Research on Cancer classified EMF [low-frequency electromagnetic fields] as a “possible” carcinogen. They have a low threshold for this category, which is rather long. It requires limited evidence of carcinogenic potential in humans and inadequate evidence in animals. This is the, “Probably should do more research just to be sure, but basically don’t worry about it,” category.

Who was Eleanor Adair, and what did she think about microwaves?

I have written about Eleanor Adair before in this blog. She was a leading expert on the interaction of microwaves with biological tissue, and was skeptical of any health hazards claims. A New York Times interview included this exchange:

Q. If I were to say to people, “Hey there’s this really cool idea: Why heat your whole house when you could use microwaves to heat yourself?” they would say: “You’ve got to be kidding. Don’t you know that microwaves are dangerous? They can even cause cancer.” What do you say to people who respond like that?

 A. I try to educate them in exactly what these fields are. That they are part of the full electromagnetic spectrum that goes all the way from the radio frequency and microwave bands, through infrared, ultraviolet, the gamma rays and all that.

And the difference between the ionizing X-ray, gamma ray region and the microwave frequency is in the quantum energy. The lower you get in frequency the lower you get in quantum energy and the less it can do to the cells in your body.

If you have a really high quantum energy such as your X-rays and ionizing-radiation region of the spectrum, this energy is high enough that it can bump electrons out of the orbit in your cells and it can create serious changes in the cells of your body such that they can turn into cancers and various other things that are not good for you.

But down where we are working, in the microwave band, you are millions of times lower in frequency and there the quantum energy is so low that they can’t do any damage to the cells whatsoever. And most people don’t realize this.

Somehow, something is missing in their basic science education, which is something I keep trying to push. Learn the spectrum. Learn that you’re in far worse shape if you lie out on the beach in the middle of summer and you soak up that ultraviolet radiation than you are if you use your cell phone.

Any new data about health effects of electromagnetic fields in the last few years?

A recent article examining the “Occupational Exposure to High-Frequency Electromagnetic Fields and Brain Tumor Risk in the INTEROCC Study: An Individualized Assessment Approach,” (Vila et al., 2018) provides the following highlights

• Evidence on health effects of long-term occupational exposure to high-frequency EMF remains weak

• Individualized cumulative occupational RF [radiofrequency, 10 MHz–300 GHz] and IF [intermediate frequency, 3 kHz–10 MHz] exposure indices were assigned to study subjects

• No clear associations with RF or IF EMF and glioma or meningioma risk were observed

• The possible role of RF magnetic fields on brain tumor promotion/progression should be further investigated.

As Bob Park said, everyone supports doing additional research (as do I). But I don’t see a lot to be worried about here.

Bill Curry concluded that 5G technology “is likely to be a serious health hazard.” Well?

I’ve written about physicist Bill Curry and his claims previously in this blog. That post begins

A recent article by William Broad in the New York Times—titled “The 5G Health Hazard That Isn’t”—tells the sad story of how unfounded fears of radiofrequency radiation were stoked by one mistaken scientist.

What is electromagnetic hypersensitivity?

Some people claim they’re extremely sensitive to weak electromagnetic fields. The SkepDoc Harriet Hall wrote a blog post titled “Myths About Electromagnetic Hypersensitivity and Multiple Chemical Sensitivity.” She begins

As if we didn’t have enough things to worry about already, now we are being told to fear our toasters. A typical headline trumpets “The Effects of Invisible Waves.” We are increasingly exposed to electromagnetic radiation from cell phones, cell phone towers, wireless Internet routers, cordless phones, and power lines. Other sources ... are our household appliances: TVs, hairdryers, light bulbs, and yes, your trusty toaster. These invisible villains are said to lead to a variety of symptoms, including poor sleep, fatigue, heart palpitations, headache, nausea, dizziness, memory impairment, prickling and burning sensations, along with skin rashes. They’ve even been blamed for depression, anxiety, colds, digestive disorders, and chronic pain. It’s called electromagnetic hypersensitivity or EHS.

Hall concludes

The symptoms described by “electromagnetic hypersensitivity” sufferers can be severe and are sometimes disabling. However, it has proved difficult to show under blind conditions that exposure to EMF can trigger these symptoms. This suggests that “electromagnetic hypersensitivity” is unrelated to the presence of EMF.

I recommend you read the entire article.

IPMB cited a point-counterpoint article that suggests cell phones are dangerous. True?

Point-counterpoint articles appear every month in the journal Medical Physics. They are a wonderful teaching tool, allowing students to consider and discuss questions at the cutting edge of medical physics. The one cited in Chapter 9 of IPMB is by Khurana, Moulder, and Orton (2008), titled “There is Currently Enough Evidence and Technology Available to Warrant Taking Immediate Steps to Reduce Exposure of Consumers to Cell-Phone-Related Electromagnetic Radiation.” Every point-counterpoint article pits one researcher against another, arguing opposing sides of the claim made in the article title. In this case, Vini Khurana supports the proposition, and John Moulder opposes it; Colin Orton is the moderator. I encourage you to read the article for yourself. I agree with Moulder’s conclusion that

weak epidemiological evidence of an association of mobile phone use with brain cancer incidence, when combined with the biophysical implausibility of a causal link and the strongly unsupportive animal studies, does not support the case that regulation of mobile phone use is urgently needed.

Last year I saw an article that says 5G cell phone radiation is unsafe! What’s up?

The Nation published an article titled “How Big Wireless Made Us Think That Cell Phones Are Safe: A Special Investigation. The Disinformation Campaign—and Massive Radiation Increase—Behind the 5G Rollout,” by Mark Hertsgaard and Mark Dowie. David Gorski published a critique of this article for the website Science-Based Medicine. He writes

The Nation indulges in fear mongering about cell phones and cancer An article published last week in The Nation likens wireless telephone companies to tobacco and fossil fuel episodes in their tactics of spreading fear, misinformation, and doubt regarding the science of cell phone radiation and health. To produce this narrative, the investigation’s authors rely on unreliable sources and cherry pick scientific studies, ignoring the scientific consensus that cell phone radiation almost certainly doesn’t cause cancer, all the while disingenuously claiming that they aren’t taking a position on the health effects of radio waves.

Read The Nation article and the critique and decide for yourself. At the least, you’ll learn how physics can be applied to medicine and biology.

What’s the bottom line regarding the risk of cancer from 5G cell phones?

Electromagnetic radiation consists of packets of energy called photons. The energy of a photon increases with the frequency of the radiation. Cancer is caused when DNA is damaged by very-high-frequency photons, such as x-rays (ionizing radiation). If the frequency is in the range of 300 GHz, the energy of a photon is far too small to disrupt bonds in DNA. It is, in fact, smaller than the energies associated with thermal motion of molecules. So, photons associated with 300 GHz radiation cannot cause cancer by damaging DNA. Of course, you could have a whole lot of 300 GHz photons, and they might pool their effort and together have enough energy to break bonds. We have a word for that: heat. 300 GHz radiation can heat tissue, but such heating is well understood and easily measured; Cell phone radiation is too weak to cause a significant temperature increase. So, we are left with no plausible mechanism for health risks from cell phone radiation. Perhaps some secondary effect could make your body less able to fight off cancer once it is induced by other mechanisms, but no one really knows how that might occur. Moreover, the epidemiological evidence suggests there is little risk. Cell phone use has increased dramatically since the turn of the century, but the incidence of brain cancer hasn’t increased. The National Cancer Institute says “The only consistently recognized biological effect of radiofrequency radiation in humans is heating... There are no other clearly established effects on the human body from radiofrequency radiation.” I wouldn’t say it’s impossible that cell phones put you at risk for cancer, but it’s unlikely. In my opinion, it’s exceedingly unlikely. We have many other things to worry about instead.

References

Foster KR, Moulder JE (2013) “Wi-Fi and Health: Review of Current Status of Research,” Health Physics, Volume 105, Pages 561-575.

Foster KR, Moulder JE (2018) “Response to Pall, ‘Wi-Fi is an Important Threat to Human Health’,” Environmental Research, Volume 445-447, Pages 445-447.

Khurana VG, Moulder JE, Orton CG (2008) “There is Currently Enough Evidence and Technology Available to Warrant Taking Immediate Steps to Reduce Exposure of Consumers to Cell-Phone-Related Electromagnetic Radiation,” Medical Physics, Volume 35, Pages 5203-5206.

Moulder JE, Foster KR, Erdreich LS, McNamee JP (2005) “Mobile Phones, Mobile Phone Base Stations and Cancer: A Review,” International Journal of Radiation Biology, Volume 81, Pages 189-203.

Pall ML (2018) “Wi-fi is an Important Threat to Human Health,” Environmental Research, Volume 164, Pages 405-416.

Sheppard AR, Swicord ML, Balzano Q (2008) “Quantitative evaluation of mechanisms of radiofrequency interactions with biological molecules and processes,” Health Physics, Volume 95, Pages 365-396.

Vecchia P, Matthes R, Ziegelberger G, Lin J, Saunders R, Swerdlow A (2009) “Exposure to High Frequency Electromagnetic Fields, Biological Effects and Health Consequences (100 kHz – 300 GHz),” Munich: International Commission on Non-ionizing Radiation Protection.

Vila, J, Turner MC, Gracia-Lavedan E, Figuerola J, Bowman JD, Kincl L, Richardson L, Benke G, Hours M, Krewski D, McLean D, Parent M-E, Sadetzki S, Schlaefer K, Schlehofer B, Schuz J, Siemiatycki J, Tongeren M, Cardis, E (2018) Occupational exposure to high-frequency electromagnetic fields and brain tumor risk in the INTEROCC study: An individualized assessment approach. Environment International, Volume 119, Pages 353-365.

The 5G Health Hazard That Isn’t

Screenshot of the start of the article
"The 5G Health Hazard That Isn’t"
by William Broad in the New York Times.

A recent article by William Broad in the New York Times—titled “The 5G Health Hazard That Isn’t”—tells the sad story of how unfounded fears of radio-frequency radiation were stoked by one mistaken scientist. Broad begins

In 2000, the Broward County Public Schools in Florida received an alarming report. Like many affluent school districts at the time, Broward was considering laptops and wireless networks for its classrooms and 250,000 students. Were there any health risks to worry about?

The district asked Bill P. Curry, a consultant and physicist, to study the matter. The technology, he reported back, was “likely to be a serious health hazard.” He summarized his most troubling evidence in a large graph labeled “Microwave Absorption in Brain Tissue (Grey Matter).”

The chart showed the dose of radiation received by the brain as rising from left to right, with the increasing frequency of the wireless signal. The slope was gentle at first, but when the line reached the wireless frequencies associated with computer networking, it shot straight up, indicating a dangerous level of exposure.

“This graph shows why I am concerned,” Dr. Curry wrote. The body of his report detailed how the radio waves could sow brain cancer, a terrifying disease that kills most of its victims.

Over the years, Dr. Curry’s warning spread far, resonating with educators, consumers and entire cities as the frequencies of cellphones, cell towers and wireless local networks rose. To no small degree, the blossoming anxiety over the professed health risks of 5G technology can be traced to a single scientist and a single chart.

Except that Dr. Curry and his graph got it wrong.

Russ Hobbie and I describe the possible effects of weak electric and magnetic fields in Section 9.10 of Intermediate Physics for Medicine and Biology. We quote a review by Moulder et al. (2005) that concludes

Overall, a weight-of-evidence evaluation shows that the current evidence for a causal association between cancer and exposure to RF [radio frequency] energy is weak and unconvincing.

In his New York Times article, Broad goes on to describe how your “skin” blocks the radio waves. That’s not how I would say it. The waves can’t penetrate your body because of “skin depth” (to learn more about skin depth, do Problem 29 in Chapter 8 of IPMB). An electromagnetic wave penetrates a conductor to a distance on the order of the skin depth, which decreases as the frequency increases. A typical 5G frequency is 3 GHz, corresponding to a skin depth of about 30 mm (a little over an inch). Therefore, deep structures in your body are somewhat shielded from this radiation. It has nothing to do with skin itself; the effect works the same when the wave tries to penetrate the surface of the ocean. It depends on the electrical conductivity. Some planned 5G networks will operate at even higher frequencies (up to 300 GHz). In that case, the skin depth would be ten times smaller than for 3 GHz, or 3 mm, similar to the thickness of skin.

If the amplitude of the electromagnetic wave was high enough, it could burn you. Most people who object to radio frequency waves aren’t worried about heating. They’re concerned about hypothetical nonthermal effects, like causing cancer.

I can think of many reasons to ditch your fancy-schmancy 5G cell phone. Cancer isn’t one of them.

Power Lines and Cancer FAQ

The Power Lines and Cancer FAQ,
by John Moulder.

In the 4th edition of Intermediate Physics for Medicine and Biology, Russ Hobbie and I wrote

An excellent discussion of the all aspects of the problem [whether radiofrequency and power-line electromagnetic fields cause cancer] is available at a frequently updated website, Powerlines and Cancer FAQ [Moulder (Web)].

Then we quoted from the website extensively

Moulder (Web, question 20A) says…

The reference was to

Moulder, J. E. (Web). Power Lines and Cancer: Frequently Asked Questions, www.mcw.edu/gcrc/cop/powerlines-cancer-FAQ/toc.html.

In the 5th edition of IPMB, the story became

John Moulder, the author of a web site about power lines and cancer that unfortunately no longer exists, said…

Yet, I wonder... Nothing disappears from the internet. After a few minutes of googling, I found the entire website saved as a pdf, available at large.stanford.edu/publications/crime/references/moulder/moulder.pdf or https://www.nrc.gov/docs/ML1126/ML112660019.pdf. You can also download it from the IPMB website, or just click here. It begins with a brief summary.

Questions and answers on the connection between power lines, electrical occupations and cancer; includes discussion of the biophysics of interactions, summaries of the laboratory and human studies, information on standards, and a bibliography.

The question-and-answer format includes cross-references to other questions (e.g., “Q12” or “Q27J”). References are listed in the bibliography (e.g., “B12”). Below, I reproduce the first question.

1) Is there a concern about power lines and cancer?

The concern about power lines and cancer comes largely from studies of people living near power lines (see Q12) and people working in “electrical” occupations (see Q15). Some of these studies appear to show a weak association between exposure to power-frequency magnetic fields and the incidence of some cancers. However:

• the more recent epidemiological studies show little evidence that either power lines or “electrical occupations” are associated with an increase in cancer (see Q19); 

• laboratory studies have shown little evidence of a link between power-frequency fields and cancer (see Q16); 

• an extensive series of studies have shown that life-time exposure of animals to power-frequency magnetic fields does not cause cancer (see Q16B); 

• a connection between power line fields and cancer is physically implausible (see Q18).

The International Commission on Non-Ionizing Radiation Protection (2001):

“In the absence of evidence from cellular or animal studies, and given the methodological uncertainties and in many cases inconsistencies of the existing epidemiologic literature, there is no chronic disease for which an etiological [causal] relation to [power-frequency fields] can be regarded as established.” (See B12)

The International Agency for Research on Cancer (2001):

“There is limited evidence in humans for the carcinogenicity of extremely low-frequency magnetic fields in relation to childhood leukaemia.... There is inadequate evidence in humans for the carcinogenicity of extremely low-frequency magnetic fields in relation to all other cancers [and] there is inadequate evidence in humans for the carcinogenicity of extremely low-frequency electric fields.” (see Q27J)

The U.S. National Institutes of Health (2002):

“The overall scientific evidence for human health risk from [exposure to power-frequency fields] is weak. No consistent pattern of biological effects from exposure to [power-frequency fields] has emerged from laboratory studies with animals or with cells. However, epidemiological studies... had shown a fairly consistent pattern that associated potential [exposure to power-frequency fields] with a small increased risk of leukemia in children and chronic lymphocytic leukemia in adults... For both childhood and adult leukemias interpretation of the epidemiological findings has been difficult due to the absence of supporting laboratory evidence or a scientific explanation linking [exposure to power-frequency fields] with leukemia.” (see Q27G).

The U.K. National Radiological Protection Board (2004):

“The epidemiological evidence indicates that exposure to power-frequency magnetic fields above 0.4 microT [4 milliG] is associated with a small absolute raised risk of leukaemia in children... However, the epidemiological evidence is not strong enough to justify a firm conclusion that [power-frequency magnetic] fields cause leukemia in children. There is little evidence to suggest... that cancer risks of other types, in children and adults, might arise from exposure to [power-frequency magnetic] fields... The results of epidemiological studies, taken individually or as collectively reviewed by expert groups, cannot be used as a basis for derivation of quantitative restrictions on exposure to [power-frequency magnetic] fields.” (see Q27H)

Overall, most scientists consider that the evidence that power line fields cause or contribute to cancer is weak to nonexistent.

The document answers 35 questions, which together provide a detailed analysis of the controversy through 2006. How I wish the FAQ was up-to-date.

The final question is

35) Who wrote this FAQ?

This FAQ document originated in the early 1990's as a USENET FAQ in sci.med.physics. The USENET FAQ was maintained by Dr. John Moulder, Professor of Radiation Oncology, Radiology and Pharmacology/Toxicology at the Medical College of Wisconsin. Dr. Moulder has taught, lectured and written on the biological effects of non-ionizing radiation and electromagnetic fields since the late 1970’s.

The USENET FAQ was converted to html in 1997 by Bob Mueller and Dennis Taylor of the General Clinical Research Center at the Medical College of Wisconsin. The FAQ was expanded and updated to serve as a teaching aid at the Medical College of Wisconsin. The web server and web management was provided by the General Clinical Research Center at the Medical College of Wisconsin. The development and maintenance of this document was not supported by any person, agency, group or corporation outside the Medical College of Wisconsin.

In August 2005, Dr. Moulder became Director of the NIH-funded Medical College of Wisconsin Center for Medical Countermeasures Against Radiological Terrorism. This new job does not leave him the time required to keep these FAQs up-to-date. When the FAQs had become more than two years out-of-date they were discontinued. There is no version more up-to-date that this PDF version....

Parts of this FAQ were derived from the following peer-reviewed publications:

• JE Moulder and KR Foster: Biological effects of power-frequency fields as they relate to carcinogenesis. Proc Soc Exp Med Biol 209:309–324, 1995. 

• JE Moulder: Biological studies of power-frequency fields and carcinogenesis. IEEE Eng Med Biol 15 (July/Aug):31–49, 1996. 

• KR Foster, LS Erdreich, JE Moulder: Weak electromagnetic fields and cancer in the context of risk assessment. Proc IEEE, 85:733–746, 1997. 

• JE Moulder: Power-frequency fields and cancer. Crit Rev Biomed Eng 26:1–116, 1998. 

• JE Moulder: Une approache biomédicale: le point de vue d'un chercheur en cancérologie. In: J Lambrozo, I Le Bis (Eds), Champs Électriques et Magnétique de Très Basse Fréquency: Electricité de France, 1998. 

• JE Moulder KR Foster: Is there a link between exposure to power-frequency electric fields and cancer? IEEE Eng Med Biol 18(2):109–116, 1999. 

• JE Moulder: The Electric and Magnetic Fields Research and Public Information Dissemination (EMF-RAPID) Program. Radiat Res 153:613–616, 2000. 

• JE Moulder: The controversy over powerlines and cancer, III Jornadas sobre Líneas Eléctricas y Medio Ambiente, Red Eléctrica de España, Madrid, 2000, pp. 159–168.

Dr. Moulder maintained similar “FAQ” documents on “Mobile (Cell) Phone Base Antennas and Human Health” and “Static EM Fields and Cancer”.

I discovered a version of the static fields FAQ at https://stason.org/TULARC/health/static-fields-cancer/index.html. I have not found the cell phone FAQ; maybe things can disappear from the internet after all. If you find it, let me know (roth@oakland.edu).

I like the Power Line FAQ’s poetic closing lines.

Public controversy about electricity and health will continue

until:

future research shows conclusively that the fields are hazardous,

or

until the public learns that science cannot guarantee absolute safety,

or

until the public and media gets bored by the subject. 

Neither of the first two outcomes are particularly likely, 

But the third may happen.

Microwave Weapons are Prime Suspect in Ills of U.S. Embassy Workers

Last Saturday, The New York Times published an article by Pulitzer Prize-winning science writer William Broad with the headline “Microwave Weapons are Prime Suspect in Ills of U.S. Embassy Workers.”

Doctors and scientists say microwave strikes may have caused sonic delusions and very real brain damage among embassy staff and family members.

The article has made quite a splash; I even heard about it on the news.

This topic is relevant to Intermediate Physics for Medicine and Biology, so I’ll address it in this post. I hesitate, however, because the science is uncertain and the topic of electromagnetic effects on health is fraught with conspiracy theories and voodoo science. Yet, the issue has more than academic importance; U.S.-Cuban relations suffered because of these unexplained health effects. So, reluctantly, I wade in.
I begin with a report from last March in the prestigious Journal of the American Medical Association (JAMA) by Swanson et al. about “Neurological Manifestations Among US Government Personnel Reporting Directional Audible and Sensory Phenomena in Havana, Cuba” (Volume 319, Pages 1125–1133).

• Question: Are there neurological manifestations associated with reports of audible and sensory phenomena among US government personnel in Havana, Cuba? 
• Findings: In this case series of 21 individuals exposed to directional audible and sensory phenomena, a constellation of acute and persistent signs and symptoms were identified, in the absence of an associated history of blunt head trauma. Following exposure, patients experienced cognitive, vestibular, and oculomotor dysfunction, along with auditory symptoms, sleep abnormalities, and headache. 
• Meaning: The unique circumstances of these patients and the consistency of the clinical manifestations raised concern for a novel mechanism of a possible acquired brain injury from a directional exposure of undetermined etiology.

The article’s claim of cognitive dysfunction has been hotly debated. A post in the blog Neuroskeptic was….er….skeptical. It concludes

Overall … the JAMA paper is pretty weak. Clearly, something has happened to make these 21 people experience so many unpleasant symptoms, but at present I don’t think we can rule out the possibility that the cause is psychological in nature.

Last week’s New York Times article was triggered by the recently proposed hypothesis that microwaves are responsible for these health issues. Russ Hobbie and I discuss the biological effects of electric and magnetic fields in Section 9.10 of IPMB. We focus on the potential of microwaves to induce tumors, and conclude that nonthermal mechanisms are implausible. In other words, radiofrequency fields can heat tissue—just like in your microwave oven—but they don’t cause cancer. The hypothesis touted in the Times article, however, is a thermal mechanism: a thermoelastic pressure wave sensed as sound by part of the inner ear called the cochlea.

Hearing induced by microwaves has been studied for years, and is known as the “Frey effect” after Allen Frey, who first reported it. A 2007 article in the journal Health Physics by James Lin and Zhangwei Wang (Volume 92, Pages 621-628) describes this phenomenon.

Hearing of Microwave Pulses by Humans and Animals: Effects, Mechanism, and Thresholds

The hearing of microwave pulses is a unique exception to the airborne or bone-conducted sound energy normally encountered in human auditory perception. The hearing apparatus commonly responds to airborne or bone-conducted acoustic or sound pressure waves in the audible frequency range. But the hearing of microwave pulses involves electromagnetic waves whose frequency ranges from hundreds of MHz to tens of GHz. Since electromagnetic waves (e.g., light) are seen but not heard, the report of auditory perception of microwave pulses was at once astonishing and intriguing. Moreover, it stood in sharp contrast to the responses associated with continuous-wave microwave radiation. Experimental and theoretical studies have shown that the microwave auditory phenomenon does not arise from an interaction of microwave pulses directly with the auditory nerves or neurons along the auditory neurophysiological pathways of the central nervous system. Instead, the microwave pulse, upon absorption by soft tissues in the head, launches a thermoelastic wave of acoustic pressure that travels by bone conduction to the inner ear. There, it activates the cochlear receptors via the same process involved for normal hearing. Aside from tissue heating, microwave auditory effect is the most widely accepted biological effect of microwave radiation with a known mechanism of interaction: the thermoelastic theory. The phenomenon, mechanism, power requirement, pressure amplitude, and auditory thresholds of microwave hearing are discussed in this paper. A specific emphasis is placed on human exposures to wireless communication fields and magnetic resonance imaging (MRI) coils.

Their introduction gives some useful numbers.

The microwave auditory phenomenon or microwave hearing effect pertains to the hearing of short-pulse, modulated microwave energy at high peak power by humans and laboratory animals (Frey 1961, 1962; Guy et al.1975a, b; Lin 1978, 1980, 2004). The effect can arise, for example, at an incident energy density threshold of 400 mJ m^-2 for a single, 10-µs-wide pulse of 2,450 MHz microwave energy, incident on the head of a human subject (Guy et al. 1975a, b; Lin 1978). It has been shown to occur at a specific absorption rate (SAR) threshold of 1.6 kW kg^-1 for a single 10-µs-wide pulse of 2,450 MHz microwave energy. A single microwave pulse can be perceived as an acoustic click or knocking sound, and a train of microwave pulses to the head can be sensed as an audible tune, with a pitch corresponding to the pulse repetition rate (Lin 1978).

The temperature increase caused by such a microwave pulse is rapid (microseconds) and tiny (microdegrees Celsius), and the associated pressure is small (tenths of a Pascal, or equivalently millionths of an atmosphere). People can hear these sounds because the cochlea is so sensitive.

One reason that microwaves might be a more plausible mechanism than sound waves for the apparent embassy attacks is acoustic impedance, discussed in Chapter 13 of IPMB. Air and water have very different impedances. When a sound wave impinges on a person, most of the acoustic energy is lost by reflection, and little (perhaps one part in a thousand) enters the fluid-filled body. Animals have evolved elaborate structures in the middle ear to mitigate this acoustic mismatch. However, a pressure wave caused by microwave heating originates inside the ear. No energy is lost by sound reflecting from the air-tissue interface.

I am no expert on thermoelastic effects, but it seems plausible that they could be responsible for the perception of sound by embassy workers in Cuba. By modifying the shape and frequency of the microwave pulses, you might even induce sounds more distinct than vague clicks. However, I don’t know how you get from little noises to brain damage and cognitive dysfunction. My brain isn’t damaged by listening to clicky sounds. Either there is more to this that I don’t understand, or—as neuroskeptic speculates—the rest of the cause is “psychological in nature.”

Right now, our country could use a hard-nosed scientist or engineer expert in the bioeffects of microwave radiation to look into this problem. Where have you gone John Moulder and Ken Foster? We need you!

Zapping Their Brains at Home

“Zapping Their Brains at Home,”
by Anna Wexler.

A couple weeks ago, Anna Wexler published an article in the New York Times titled “Zapping Their Brains at Home.”

Earlier this month, in the journal Annals of Neurology, four neuroscientists published an open letter to practitioners of do-it-yourself brain stimulation. These are people who stimulate their own brains with low levels of electricity, largely for purposes like improved memory or learning ability. The letter, which was signed by 39 other researchers, outlined what is known and unknown about the safety of such noninvasive brain stimulation, and asked users to give careful consideration to the risks.

I worked on brain stimulation when at the National Institutes of Health, and Russ Hobbie and I analyze neural stimulation in Intermediate Physics for Medicine and Biology. So what is my reaction to these do-it-yourselfers? My first thought was “Yikes…this sounds like trouble!” But the more I think about it, the less worried I am.

We are talking about transcranial direct current stimulation, which uses weak currents applied to the scalp. I have always been surprised that such tiny currents have any effect at all; see my editorial “What Does the Ratio of Injected Current to Electrode Area Not Tell Us About tDCS?” (Clinical Neurophysiology, Volume 120, Pages 1037–1038, 2009). My advice to the do-it-yourselfers is not so much “be careful” but rather “don’t get your hopes up.”

Of the four coauthors on the letter in Annals of Neurology, the only one I know is Alvaro Pascual-Leone, who I worked with while at NIH and who we cite several times in IPMB. Below I list the main points raised in the letter:

• Stimulation affects more of the brain than a user may think 
• Stimulation interacts with ongoing brain activity, so what a user does during tDCS changes its effects 
• Enhancement of some cognitive abilities may come at the cost of others 
• Changes in brain activity (intended or not) may last longer than a user may think 
• Small differences in tDCS parameters can have a big effect 
• tDCS effects are highly variable across different people 
• The risk/benefit ratio is different for treating diseases versus enhancing function

What do I think of do-it-yourselfers in general? I have mixed feelings. Heaven help us if they start fooling around with heart defibrillators, which could be suicidal. For transcranial magnetic stimulation, I think the biggest risk would be the construction of a device that sends kiloamps of current through a coil. I have always thought that TMS is more dangerous for the physician (who often holds the coil) than for the patient. Moreover, the induced current in the brain is larger for TMS than for tDCS. I would be wary of do-it-yourself magnetic stimulation. But for D.I.Y.ers using relatively low-level electrical current applied to the scalp, if someone educates themself on the technique and follows reasonable safety recommendations, then I don’t see it as a problem.

Wexler ends her letter

The open letter this month is about safety. But it also a recognition that these D.I.Y. practitioners are here to stay, at least for the time being. While the letter does not condone, neither does it condemn. It sticks to the facts and eschews paternalistic tones in favor of measured ones. The letter is the first instance I’m aware of in which scientists have directly addressed these D.I.Y. users. Though not quite an olive branch, it is a commendable step forward, one that demonstrates an awareness of a community of scientifically involved citizens.

If you want to read more by Wexler, look here and here.

My final, and admittedly self-serving, advice to the D.I.Y.ers: go buy a copy of Intermediate Physics for Medicine and Biology, so you can learn the scientific principles behind this and other techniques.

Biomagnetism Therapy: Pseudoscientific Twaddle

Voodoo Science,
by Robert Park.

Ever since Robert Park—author of Voodoo Science and the weekly column What’s New—suffered a stroke in 2013, I have been searching for another debunker of pseudoscience. Finally, I’ve found her! Harriet Hall is a retired physician and former Air Force flight surgeon. Every week she battles nonsense in the blog sciencebasedmedicine.org. In her November 20 entry, she addressed “biomagnetic therapy.”

Biomagnetism Therapy: Pseudoscientific Twaddle

In a television interview, a practitioner of biomagnetic therapy claimed she had cured her own breast lump and the metastatic cancer of another person. I wonder how many viewers believed her. On the “official website” of biomagnetism therapy, http://biomagnetism.net/, they claim it is “the answer to ALL your health problems… an all-natural, non-invasive therapy proven to prevent, diagnose and treat countless diseases, chronic illnesses and degenerative health problems.”

Sound too good to be true? Of course it does! You are already skeptical. If you read further, you will become even more skeptical….”

She concludes

…It pains me to see misinformation such as this fed to gullible patients. Using biomagnetic therapy isn’t likely to harm patients physically, but it’s likely to harm their comprehension of science. It’s likely to waste their money, and it could delay getting treatments that do work. Perhaps the worst thing is that people who practice this therapy are deceiving themselves. They don’t understand science, and they mistake testimonials for evidence of efficacy. They don’t understand the need for controlled studies. They don’t understand placebo effects, suggestion, expectation, regression to the mean, the natural course of illness, and all the other things that can lead people to believe a bogus treatment works. It is particularly tragic that anyone trained as an MD could have such poor critical thinking skills and be misled by such egregious pseudoscience.

Russ Hobbie and I have an entire chapter about biomagnetism in Intermediate Physics for Medicine and Biology. We discuss the measurement of the very small magnetic fields produced by the brain (magnetoencephalography) and the use of rapidly changing magnetic fields to stimulate neurons (transcranial magnetic stimulation). We also devote a chapter to magnetic resonance imaging. These are important topics, but they often get mixed up with phony claims about “biomagnetic therapy.”

If you doubt this is a real problem, go to Google and search for “biomagnetism” (the title of Chapter 8 in IPMB). The first site you get starts “One of the most peculiar therapy systems that FAIM [Foundation for Alternative and Integrative Medicine] is investigating is one that uses ordinary magnets to heal. Although magnets have been used in therapies for a long time, this particular method uses pairs of magnets to neutralize disease-causing pathogens in the body...” The second site begins “Yes! It’s the answer to ALL your health problems…” The third describes “The Revolutionary Therapy based on the Biomagnetic Pairs discovered by Dr. Isaac Goiz Durán, MD in 1988...” The fourth is the “Official website for Biomagnetism classes in the USA with Dr. Isaac Goiz Durán...” Finally, the fifth site in the list is Wikipedia’s entry on biomagnetism (the measurement of weak magnetic fields produced by the body). The first four are twaddle; the fifth is reputable.

Women Aren’t Supposed to Fly,
by Harriet Hall.

If you want to learn more about Harriet Hall, read her autobiography Women Aren’t Supposed to Fly, in which she describes her experiences in medical school and the Air Force. From the Preface:

There’s an old curse “may you live in interesting times.” I lived in an era when society was starting to allow women to enter male-dominated fields, but didn’t yet entirely approve. Someone said, “Whatever women do they must do twice as well as men to be thought half as good. Luckily this is not difficult.” Actually, it was difficult. It was frequently frustrating, sometimes painful, often ridiculously funny, and always interesting. Come with me on a ramble through my education and career and let me tell you what it was like.

What Women Aren’t Supposed to Fly does not explain is how Hall ended up a lampooner of baloney and poppycock. She needs to write a second book, telling that story. I’m sure it would be equally fascinating and amusing.

I’d have preferred another physicist pick up Bob Park’s banner, but I’ll take what I can get. Harriet Hall, keep up the good work and let’s end this “biomagnetic therapy” rubbish.

Eleanor Adair (1926-2013)

Eleanor Adair, who studied the health risks of microwave radiation, died on April 20 in Hamden, Connecticut at the age of 86. A 2001 interview with Adair, published in the New York Times, began

Eleanor R. Adair wants to tell the world what she sees as the truth about microwave radiation.

New widely reported studies have failed to find that cellular phones, which use microwaves to transmit signals, cause cancer. And most academic scientists say the microwave radiation that people are exposed to with devices like cell phones is harmless. But still, Dr. Adair knows that many people deeply fear these invisible rays.

She knows that many people hear the word “radiation” and assume that all radiation is dangerous, equating microwaves to the very different X-rays.

Microwaves, she points out, are at the other end of the electromagnetic spectrum from high energy radiation like X-rays and gamma rays. And unlike gamma rays and X-rays, which can break chemical bonds and injure cells, even causing cancer, microwaves, she says, can only heat cells. Of course, if cells get hot enough, they can die, but the heat level has to be closer to that in an oven than the extremely low level from cell phones.

The interview ends with this exchange:

Q. If I were to say to people, “Hey there’s this really cool idea: Why heat your whole house when you could use microwaves to heat yourself?” they would say: “You’ve got to be kidding. Don’t you know that microwaves are dangerous? They can even cause cancer.” What do you say to people who respond like that?

A. I try to educate them in exactly what these fields are. That they are part of the full electromagnetic spectrum that goes all the way from the radio frequency and microwave bands, through infrared, ultraviolet, the gamma rays and all that.

And the difference between the ionizing X-ray, gamma ray region and the microwave frequency is in the quantum energy. The lower you get in frequency the lower you get in quantum energy and the less it can do to the cells in your body.

If you have a really high quantum energy such as your X-rays and ionizing-radiation region of the spectrum, this energy is high enough that it can bump electrons out of the orbit in your cells and it can create serious changes in the cells of your body such that they can turn into cancers and various other things that are not good for you.

But down where we are working, in the microwave band, you are millions of times lower in frequency and there the quantum energy is so low that they can’t do any damage to the cells whatsoever. And most people don’t realize this.

Somehow, something is missing in their basic science education, which is something I keep trying to push. Learn the spectrum. Learn that you’re in far worse shape if you lie out on the beach in the middle of summer and you soak up that ultraviolet radiation than you are if you use your cell phone.

Q. Some people say that with the ever-increasing exposure of the population to microwaves—cell phones have really taken off in the past few years—we need to redouble our research efforts to look for dangerous effects of microwaves on cells and human tissues. Do you agree?

A. No. All the emphasis that we need more research on power line fields, cell phones, police radar—this involves billions of dollars that could be much better spent on other health problems. Because there is really nothing there.

We don’t cite Adair’s research in the 4th edition of Intermediate Physics for Medicine and Biology, but we do cover the interaction of electromagnetic fields with tissue in Chapter 9. Much of our discussion is about powerline (60 Hz) fields, but many of the same considerations apply to microwaves. In our discussion, we do cite Robert Adair, Eleanor’s husband and an emeritus professor of physics at Yale, who shares his wife’s interest in the health effect of microwave radiation.

Adair won the d’Arsonval Award, presented by the Bioelectromagnetics Society, to recognize her accomplishments in the field of bioelectromagnetics. In an editorial announcing the award, Ben Greenebaum writes (Bioelectromagnetics, Volume 29, Page 585, 2008)

It gives me great pleasure to introduce Dr. Eleanor R. Adair, the recipient of the Bioelectromagnetics Society’s 2007 D’Arsonval Award, as she presents her Award Lecture (Fig. 1). Dr. Adair is being honored by the Society for her body of work investigating physiological thermoregulatory responses to radio frequency and microwave fields. Her bioelectromagnetic career began with extensive experimental studies of electromagnetic radiation-induced thermophysiological responses in monkeys and concluded with experiments that accomplished the critical extrapolation of the earlier findings to humans. I believe that this body of work constitutes a majority of the literature on the latter topic.

She spent most of her career as a research scientist at the John B. Pierce Foundation Laboratory at Yale University, but finished it as a scientist at the US Air Force’s Brooks City Base in San Antonio, Texas. As she notes in her D’Arsonval address [Adair, 2008], she took her undergraduate degree at Mount Holyoke College in 1948 and her doctorate in psychology at the University of Wisconsin-Madison in 1955. Interspersed among her academic accomplishments in Madison were others—marriage to Robert Adair and children. We should not forget that combining a research career and family at that time was much rarer and required overcoming greater difficulties than those still encountered today. Those of us who have interacted with Dr. Adair over the years know that she has determination in plenty.

Dr. Adair was a charter member of the Society and was its Secretary-Treasurer (1983–1986) during a difficult time, when the Society decided to replace its first Executive Director with Bill Wisecup. She has also been active outside the Society, both with groups concerned with research into bioelectromagnetic effects and with groups concerned with the implications of these results.

However, it is for her overall scientific contributions to bioelectromagnetics that she is being presented the D’Arsonval Award. The criteria for the Award state that “. . . the D’Arsonval Medal is to recognize outstanding achievement in research in the field of Bioelectromagnetics.” And that is the topic that she will address today in her presentation entitled, “Reminiscences of a Journeyman Scientist.”

For those who want to read Adair's own words, you can find her presentation at:

Adair. E. R. (2008) “Reminiscences of a journeyman scientist: Studies of thermoregulation in non-human primates and humans,”  Bioelectromagnetics  Volume 29, Pages 586–597.

Murderous Microwaves

I have written previously on the topic of cell phone electromagnetic radiation and cancer, but the issue remains a concern among the general public. Kenneth Foster reviewed three new books about the risks associated with cell phones in the March issue of IEEE Spectrum (disclaimer: I have not read any of these books):

Disconnect: The Truth About Cell Phone Radiation, What the Industry Has Done to Hide It, and How to Protect Your Family, by Devra Davis;

Zapped: Why Your Cell Phone Shouldn’t Be Your Alarm Clock and 1268 Ways to Outsmart the Hazards of Electronic Pollution, by Ann Louise Gittleman

Dirty Electricity: Electrification and the Diseases of Civilization, by Samuel Milham.

Foster writes

Do you feel zapped, disconnected, electronically polluted by electromagnetic fields in your homes and workplace? Are you fearful of your electricity? These three books will feed your fears.

But are such fears justified? Public debates have been going on for more than a century about the possible health hazards of electromagnetic fields from power lines and radio-frequency energy from broadcast transmitters—and now cellphones. At the same time, health agencies have repeatedly reviewed the scientific literature and found no clear evidence of a problem. How can these totally different perspectives be reconciled?

Foster ultimately concludes that these perspectives can’t be reconciled. He counters these alarmist books with exhaustive scientific studies, such as Exposure to High Frequency Electromagnetic Fields, Biological Effects and Health Consequences (100 kHz–300 GHz), Edited by Paolo Vecchia et al., International Commission on Non-Ionizing Radiation Protection, 2009; and Risk Analysis of Human Exposure to Electromagnetic Fields, by Zenon Sienkiewicz, Joachim Schüz, Aslak Harbo Poulsen, and Elisabeth Cardis, report of the European Health Risk Assessment Network on Electromagnetic Fields Exposure, 2010. The first report concludes that

In the last few years the epidemiologic evidence on mobile phone use and risk of brain and other tumors of the head has grown considerably. In our opinion, overall the studies published to date do not demonstrate a raised risk within approximately ten years of use for any tumor of the brain or any other head tumor. However, some key methodologic problems remain—for example, selective non-response and exposure misclassification. Despite these methodologic shortcomings and the still limited data on long latency and long-term use, the available data do not suggest a causal association between mobile phone use and fast-growing tumors such as malignant glioma in adults, at least those tumors with short induction periods. For slow-growing tumors such as meningioma and acoustic neuroma, as well as for glioma among long-term users, the absence of associations reported thus far is less conclusive because the current observation period is still too short. Currently data are completely lacking on the potential carcinogenic effect of exposures in childhood and adolescence.

In the 4th edition of Intermediate Physics for Medicine and Biology, Russ Hobbie and I examine this topic in Section 9.10, Possible Effects of Weak External Electric and Magnetic Fields. We focus on power line (60 Hz) fields (another story….), but many of the same conclusions apply to cell phone (1 GHz) fields. A key factor is the energy of a microwave photon.

Radiated energy is in the form of discrete packets or photons, whose energy is related to the frequency of oscillation of the fields. The energy of each photon is E = hν, where h is Planck’s constant and ν the frequency. At room temperature, the energy of random thermal motion is k_BT = 4 × 10⁻²¹ J. At 60 Hz, the energy in each photon is much smaller: 4 × 10⁻³² J. At 100 MHz it is 7 × 10⁻²⁶ J.

Therefore, cell phone frequencies correspond to photon energies that are nearly 10,000 times less than thermal energies. Moreover, the energy required to break chemical bonds is hundreds of times greater than thermal energies. If cancer is caused by the breaking of bonds in DNA by photons, then cell phone photons are one millions times too weak to cause cancer. If enough photons were present, the tissue temperature could rise, but no one has evidence that there is a significant heating of the brain by photons; the fields are not that strong. We are left with no plausible mechanism connecting microwaves and cancer.

With weak epidemiological evidence and no mechanism, I remain a hard-boiled skeptic. In fact, my only reservation with Foster’s review is that his criticisms may have been too tame. My views are closer to physicist Bob Park, who is a vocal (and often sarcastic) critic of those who insist that cell phones cause cancer. Nevertheless, even Foster’s mild criticisms triggered a heated debate in the comments section following his review. Interestingly, most of the comments make emotional arguments, not scientific ones, indicating the need for a better understanding by the pubic of the basic physics of how electromagnetic fields interact with tissue. (At this point, I again plug our book, Intermediate Physics for Medicine and Biology, as the best source to learn the physics—although I admit on this one claim I may be slightly biased.)

So who should you believe in this debate? How about the National Cancer Institute? It is hard to think of a more unbiased or authoritative source of information. Their fact sheet provides a science-based analysis of the issue. But Ken Foster is a pretty reliable source of information too. He has spent nearly 40 years studying electricity and magnetism, with much of that analyzing the biological effects of E and M fields. His 1989 paper “Dielectric-Properties of Tissues and Biological Materials: A Critical Review,” (Critical Reviews in Biomedical Engineering, Volume 17, Pages 25–104), written with Herman Schwan, is a highly-cited classic. Foster’s article “Risk Management: Science and the Precautionary Principle” (Science, Volume 288, Pages 979–981, 2000) provides useful insight into the role of scientific evidence in evaluating risk. Russ and I cite several of Foster’s papers in the 4th edition of Intermediate Physics for Medicine and Biology, including

Foster, K. R. (1996) “Electromagnetic Field Effects and Mechanisms: In Search of an Anchor,” IEEE Engineering in Medicine and Biology, Volume 15, Pages 50–56.

Foster, K. R., and H. P. Schwan (1996) “Dielectric Properties of Tissues.” In C. Polk and E. Postow, eds. Handbook of Biological Effects of Electromagnetic Fields, Boca Raton, FL, CRC Press, Pages 25–102.

Moulder, J. E., and K. R. Foster (1995) “Biological Effects of Power-Frequency Fields as They Relate to Carcinogenesis,” Proceedings of the Society of Experimental Biology and Medicine, Volume 209, Pages 309–323.

Moulder, J. E., and K. R. Foster (1999) “Is There a Link Between Power-Frequency Electric Fields and Cancer?” IEEE Engineering in Medicine and Biology Magazine, Volume 18, Pages 109–116.

(Note: when preparing this blog entry, I found that we have the title to the last paper incorrect in our book. It should be "Is There a Link Between Exposure to Power-Frequency Electric Fields and Cancer?" I will correct that in the erratum, found at the book website.)

In conclusion, I don’t believe the evidence supports the hypothesis that cell phones cause cancer. Give me some convincing new evidence or a plausible mechanism, and I’ll reconsider.