There’s a book to be written about the history of radiofrequency radiation (“RFR”)If you don’t exactly understand what RFR is in the first place, I recommend you check out this earlier article for scientific context on EMFs broadly. research and regulation in the US.

From de Lorge’s rhesus monkey experiments in 1976 to the EPA’s EMF budget cut in 1995 to the assumption for exposure measurement purposes that every person in the US is a 6’2”, 220 pound man, there’s a series of unlikely events that brought us to where we are today.

But when you cut away all the bizarre twists of fate and the characters, there’s one idea at the heart of the US’ flawed approach to radiofrequency radiation regulation: the divide between “thermal” and “non-thermal” effects.

From the FCC’s very first cellular telephone radiation regulations in 1996 to those today (which are effectively identical), the government has maintained that the limits are only in place to protect against acute thermal effects, and that there is not robust enough scientific evidence to consider non-thermal effects in setting limits.

The thermal divide

So what are these “thermal” vs. “non-thermal” effects?

By way of background, radiofrequency radiation at a high enough power density has the ability to heat up matter. This is how microwave ovens work (which function at a similar band of radiation as Wi-Fi, Bluetooth, and modern cell service). And it stands to reason that if RFR were to heat up your body enough, bad things might happen.

This was experimentally shown by Dr. John de Lorge at the Naval Aerospace Medical Research Lab in Pensacola, Florida in 1976.

Imagine this scene (I’ll spare you an illustration): Dr. de Lorge placed male rhesus monkeys in styrofoam restraint chairs, put thermometers up their rectums, and then radiated them with radiofrequency waves while testing their response time to auditory signals. He found that when the internal body temperature of the monkeys was increased by 1 degree Celsius due to the radiation, their response time suffered.

(Would it surprise you to learn that this 1976 finding of rhesus monkey rectal temperatures — and later replications of similar studies in other monkeys and rats — is still the basis on which we regulate cell phone radiation exposure today? It certainly surprised me!)

Thanks to that study and the similar ones that followed in other monkeys and rats, we determined that if an organism’s tissue were heated up by one degree Celsius, that would be bad. As shown in Dr. de Lorge’s work, the monkeys then start to exhibit behavioral abnormalities. I think of this as getting “feverish” — their body temperature is literally increasingHeating up the average human by 1 degree Celsius brings you to 100.4 degrees Fahrenheit — definitely enough to wonder if you have a fever..

This idea — bad things happening when animals or humans are heated up by 1 degree Celsius by radiation — became defined as the “thermal effects” of radiofrequency radiation. And the scientific establishment rightly decided that these needed to be avoided.

Regulators come in

I’ll save you the details of how it was modeled out and codified, but in brief: in 1991, the IEEE set forth a standardThis version of the document is hard to find online, I’ve uploaded it here. It has been highlighted by someone, I’m not sure who. for radiofrequency radiation that was intended to protect against acute thermal effects, but explicitly not against any possible non-thermal effects, and nothing relating to chronic, long-term exposure. In 1996, the FCC adopted this standard (including some input from NCRP report 86) as the first regulations around cellular telephone communications. And in 2025 — today — those limits remain the same.

This regulation is why, when you buy a new iPhone, there’s a little card in the packaging that says that the phone complies with FCC limits for radiofrequency radiation, expressed in “SAR” levels like 1.6 W/kg. Some people I speak with are under the impression that radiation from cell service can’t have any effect on humans because it is “non-ionizing” (which it is), and as such it isn’t regulated. But clearly this is not true: the FCC regulates at least some of the potential effects of cell phones, which occurs through radiofrequency radiation.

I want to be very clear here, with no tin-foil hat involved:

  1. The US Government’s regulatory limits for RFR exposure are set by the FCC (see paragraph 6 under section II)
  2. Those limits were first set in 1996 and the same guidelines broadly remain in effect today (see paragraph 6 again)
  3. Those limits are explicitly only meant to address thermal effects, and not to account for any possible non-thermal effects (see paragraph 152 and quote below — this whole document is from the FCC’s last review of the guidelines, in 2019):

… we have rigorously analyzed our existing RF exposure framework and have dismissed the notion that the existing framework should be altered on account of any “non-thermal” effects.

The reality that non-thermal effects are not addressed is undisputed. Here’s a letter from the EPA in 2002, saying in part:

The FCC’s current exposure guidelines… are thermally based, and do not apply to chronic, nonthermal exposure situations. They are believed to protect against injury that may be caused by acute exposures that result in tissue heating or electric shock and burn.

Federal health and safety guidelines have not yet developed policies concerned possible risk for long-term, nonthermal exposures.

(And again, the guidelines set in 1996 were the same in 2002 and remain the same today.)

But what about…

So… what are non-thermal effects of RFR?

Well, basically, they are any biological effects that occur below the threshold that heats a human up by one degree Celsius. We’ll get to whether these exist or not in a moment. But it is first important to recognize:

If non-thermal effects of radiofrequency radiation do exist, then today’s regulatory limits on radiofrequency emissions do not account for them. Those non-thermal effects are explicitly excluded for consideration in setting the limits.

And so we wonder: do non-thermal effects of radiofrequency radiation exist?

A little government inside baseball: the FCC, despite being responsible for ultimately setting and enforcing RFR limits due to their device-licensing authority, is not a health agency. In fact, in Appendix I in this 2001 Government Accountability Office (GAO) report on the matter, the FCC says:

The report, in explaining the basis for the FCC’s exposure limit (pp. 21-22), could be misinterpreted as implying that the FCC has come to its own conclusions regarding the adequacy of our exposure limits with respect to the incorporation of safety margins and the evaluation as to whether “non-thermal” biological effects are addressed by them. I reiterate, as the report notes elsewhere, the FCC has neither primary jurisdiction nor expertise in health and safety matters. The determinations the report refers to have been made, not by us, but by the expert standards-setting organizations which developed the recommendations upon which our exposure criteria are based and also by the various federal health and safety agencies consulted by the FCC in developing the exposure limits.

So, basically, the FCC is saying that they did not “come to [their] own conclusions” about the limits, because they have “neither primary jurisdiction nor expertise in health and safety matters.” They just followed the determinations of “expert standards-setting organizations” and federal health and safety agencies (like the FDA).

Well, in 1999, three years after the initial regulations were set by the FCC, that very FDA — a federal health agency responsible for a program controlling radiation from electronic products under the Radiation Control for Health and Safety Act of 1968 — started to get concerned that this “thermal effects only” assumption might not be wrong.

On the basis of a number of academic studies that had been conducted (e.g. Lai & Singh, 1995 and 1996; Balcer-Kubiczek & Harrison, 1991; Szmigielski et al., 1982; Repacholi et al., 1997; and so on), the FDA was worried about non-thermal issues, and especially about the potential carcinogenicity of radiofrequency radiation.

The typical way the FDA goes about investigating such matters is to propose a study. And propose they did. In a 1999 letter to the National Toxicology Program at the National Institute for Environmental Health Sciences, the FDA writes:

On behalf of the Food and Drug Administration (FDA), I am nominating the following chemicals/agents to the National Toxicological Program : 1) Center for Device and Radiological Health (CDRH) - Radio Frequency Radiation Emissions of Wireless Communication Devices - with a high priority…

They go on to say (emphasis mine):

Currently cellular phones and other wireless communication devices are required to meet the radio frequency radiation (RFR) exposure guidelines of the Federal Communications Commission (FCC), which were most recently revised in August 1996. The existing exposure guidelines are based on protection from acute injury from thermal effects of RFR exposure, and may not be protective against any non-thermal effects of chronic exposures.

[The studies cited above, and others] suggest a potential carcinogenic effect from the digital phone signal using this animal model. There is wide agreement within the international scientific community regarding the types of research needed to assess whether RFR from wireless communications poses a health risk to users. … Animal experiments are crucial because meaningful data will not be available from epidemiological studies for many years due to the long latency period between exposure to a carcinogen and the diagnosis of a tumor.

There is currently insufficient scientific basis for concluding either that wireless communication technologies are safe or that they pose a risk to millions of users.

This research nomination for animal studies on radiofrequency radiation was intended by the FDA to inform their understanding about whether RFR could have non-thermal effects. And if it could, they would presumably recommend changes to the FCC’s regulatory limits.

And so the NTP was off to the races on the necessary studies! The very next year they had research results.

… kidding, of course. Nothing in government moves that fast. It actually took 19 years.

A study emerges!

After the nomination in 1999, design for the test began in 2005, and testing ran from 2010-2018. The study cost thirty million dollars. This is — as far as I’m aware — the first and only government study on cell phone radiofrequency radiation… ever.

It had some flaws. Like: it was approved and funded when only 2G and 3G networks existed, so it didn’t cover 4G or 5G. And smartphones didn’t really exist, so it didn’t cover Wi-Fi or Bluetooth.

But still! We’ll finally get to find out, with US Government, National Toxicology Program gold-standard rigor, if RFR can have non-thermal effects. And if it can, it would presumably cause us to create new limits and regulations addressing this non-thermal concern, which has been explicitly never addressed.

In 2018, we finally get the results of this $30 million, 10+ year study, and… yes! Non-thermal RFR is associated with issues (this has been shown by non-government studies for a long time, but now the government itself is showing it)!Note: “Clear Evidence” is the highest of the NTP’s four tiers of evidence when conducting this type of experiment. “Some Evidence” is also considered a positive finding. Then there’s a category for uncertain findings (“Equivocal Evidence”), and then a negative finding (“No Evidence”). They do not say “Clear Evidence” — or even “Some Evidence” — lightly.

The NTP studies found that high exposure [over the course of two years] to RFR (900 MHz) used by cell phones was associated with:

Clear evidence of an association with tumors in the hearts of male rats. The tumors were malignant schwannomas.

Some evidence of an association with tumors in the brains of male rats. The tumors were malignant gliomas.

Some evidence of an association with tumors in the adrenal glands of male rats. The tumors were benign, malignant, or complex combined pheochromocytoma.

It was unclear if tumors observed in the studies were caused by exposure to RFR in female rats (900 MHz) and male and female mice (1900MHz).

Plus, in 2019, they published a followup article showing that RFR exposure was associated with an increase in DNA damage.

Specifically, they found RFR exposure was linked with significant increases in DNA damage in: the frontal cortex of the brain in male mice, the blood cells of female mice, and the hippocampus of male rats.

The Ramazzini Institute in Italy quickly replicated these findings and came to similar conclusions.

Wow. This must have really opened the door for things to change, right?

… nope.

The director of the FDA’s Center for Devices and Radiological Health, Jeffrey ShurenNever a great sign when your Wikipedia page has but two sections: “Education” and “Conflict of interest controversy” — from the very agency that nominated this research in 1999 — basically said “eh we don’t agree.”

(Amusingly, a big part of his justification is because the NTP study was done on animals and not humans. Even though the original 1999 nomination explicitly asked for — you guessed it — animal studies.)

The FCCAs an aside, here’s an excellent monograph titled “Captured Agency,” published at the Harvard University Center for Ethics by Norm Alster, covering the depths to which the FCC is subject to regulatory capture by the industries it polices. picked Shuren’s statement up and ran with it. In their 2019 filing (cited above), paragraph 10:

Upon review of the record, we find no appropriate basis for and thus decline to initiate a rulemaking to reevaluate the existing RF exposure limits. This decision is supported by our expert sister agencies, and the lack of data in the record to support modifying our existing exposure limits. … The Director of FDA’s Center for Devices and Radiological Health [Dr. Shuren] advised the Commission, as recently as April 2019, that “no changes to the current standards are warranted at this time.”

They go on to cite Dr. Shuren’s statement repeatedly in their rationale with effectively no other sources, along with a number of references to “our expert sister agencies” in the plural, when, as far as I can tell, Dr. Shuren’s statement and its derivatives is the only cited health agency source.

So, to recap:

  • 1996: FCC (not a health agency) sets limits on radiofrequency radiation, explicitly only accounting for thermal effects
  • 1999: FDA asks for NTP animal studies on potential non-thermal effects
  • 2018: gold-standard NTP toxicology study comes out with clear evidence of non-thermal effects, including increased incidence of malignant cancers
  • 2018: Dr. Shuren at FDA says he disagrees with NTP results
  • 2019: FCC leans on Dr. Shuren’s statement to justify no changes, and maintenance of their policy of only addressing thermal effects

What came after?

Well, at least we then embarked on followup research, right?

I mean, the NTP says:

NTP studies of RFR used in 2G and 3G cellphones do not apply to 4G or 5G technologies. These newer technologies use different methods of signal modulation than NTP used in the studies. The NTP studies also did not investigate frequencies and modulations used for Wi-Fi.

So those would be good things to study, I imagine. And we’d also want to investigate the issues other than cancer:

NTP found lower body weights among newborn rats and their mothers, especially when exposed to high levels of RFR during pregnancy and lactation, yet these animals grew to normal size. They also found that RFR exposure was associated with an increase in DNA damage.

Plus, between 1999 and 2018, we went from roughly 30% cellphone penetration (and thus daily RFR exposure) in the US to over 95% — which I’d of course think would be cause for further study.

And in fact, according to the NTP:

NIEHS scientists … undertook research to better understand some of the findings seen in the earlier Radio Frequency Radiation (RFR) rodent studies

The goals of this new research were to determine the impact of RFR exposure on behavior and stress, conduct real-time physiological monitoring, including evaluation of heart rate, investigate whether RFR exposure induces heating, and evaluate further whether RFR exposure causes DNA damage.

They even went so far as to design and develop a novel small-scale RFR exposure system and conduct a series of in vivo rodent studies to test the new exposure system. This would allow them to run studies more cost-effectively as compared to the big system they used for the original one.

But, in 2024, they suddenly decided and announced:

The research using this small-scale RFR exposure system was technically challenging and more resource intensive than expected. In addition, this exposure system was designed to study the frequencies and modulations used in 2G and 3G devices, but is not representative of newer technologies such as 4G/4G-LTE, or 5G (which is still not fully defined). Taking these factors into consideration, no further work with this RFR exposure system will be conducted and NIEHS has no further plans to conduct additional RFR exposure studies at this time.

To paraphase: “we were running more experiments on RFR. But then we realized it was challenging, and we weren’t even studying the new technologies in use today. So we decided to stop, and rather than studying those modern technologies, we will study nothing.”

So, no. As far as I’m aware, the US Government has no plans to further study RFR. They’ve never studied Wi-Fi, 4G, 5G, or Bluetooth. They dropped their followup studies on 2G and 3G. And the only study they ever ran — again, a gold-standard, $30 million toxicology study — showed clear evidence of carcinogenicity (and DNA damage, and more) at non-thermal levels.

The FCC loses in court

This is pretty baffling to me. We’re talking about something that ~100% of Americans are exposed to, pretty much all day. And we seem to be ignoring real cause for the regulatory limits to be updated.

I’m not the only one. In 2021, the FCC lost a lawsuit filed by the Environmental Health Trust (who does excellent research and advocacy work on all of this), which had been joined with a case brought by, incidentally, Robert F Kennedy, Jr., now Secretary of Health and Human Services for the United States.

The DC Circuit Court of Appeals decision linked above is a good read. Here’s a key passage from the Court regarding Dr. Shuren’s statement on which the FCC relies to dismiss any changes to the rules (emphasis mine):

The statements from the FDA on which the Commission’s order relies … explain that the FDA has reviewed certain information—here, “all,” “the weight,” or “the totality” of “scientific evidence.” And they state the FDA’s conclusion that, in light of that information, exposure to RF radiation at levels below the Commission’s current limits does not cause harmful health effects. But [the FDA statements] offer “no articulation of the factual . . . bases” for the FDA’s conclusion. In other words, they do not explain why the FDA determined, despite the studies and comments that Petitioners cite, that exposure to RF radiation at levels below the Commission’s current limits does not cause harmful health effects. Such conclusory statements “cannot substitute for a reasoned explanation,” for they provide “neither assurance that the [FDA] considered the relevant factors nor [do they reveal] a discernable path to which the court may defer.” They instead represent a failure by the FDA to address the implication of Petitioners’ studies: The factual premise—the non-existence of non-thermal biological effects—underlying the current RF guidelines may no longer be accurate.

And the Court on the FCC’s ultimate decision (emphasis mine)An important note: the Court does say that the FDA’s objection to the NTP study’s carcinogenic conclusions specifically are “reasoned” (i.e. they didn’t just dismiss it out of hand, they presented some arguments). The Court doesn’t opine on whether they are right or not — not the Court’s place — but they do say that FDA made some arguments there, specifically around perceived flaws in the study design: the whole-body radiation, the exposure levels, the duration, and, amusingly, that the study was based on 2G/3G and not WiFi or 5G. Dr. Ronald Melnick, one of the NTP study designers, published an in-depth rebuttal to all that.:

The Commission’s purported reasoning in this case is that it chose to rely on the FDA’s evaluation of the studies in the record. Absent explanation from the FDA as to how and why it reached its conclusions regarding those studies, however, we have no basis on which to review the reasonableness of the Commission’s decision to adopt the FDA’s conclusions. Ultimately, the Commission’s order remains bereft of any explanation as to why, in light of the studies in the record, its guidelines remain adequate. The Commission may turn to the FDA to provide such an explanation, but if the FDA fails to do so, as it did in this case, the Commission must turn elsewhere or provide its own explanation.

The Court remanded the FCC to provide more explanation for a number of specific decisions, including the health implications of long-term exposure to RFR, impacts of RFR on children, and more. This was in 2021. It’s been nearly four years and they have yet to do so.

Where to from here?

As it stands, I believe a fundamentally flawed assumption remains in our regulation of the cell phones, Wi-Fi, and connected devices we use all day.

The US Government — through the FCC — has taken the position that thermal effects are the only proven impacts of such radiation, and that there is insufficient evidence of any effects from non-thermal radiation to address them.

I simply don’t believe the scientific record supports this. From the government’s own 10-year, $30 million NTP toxicology study, to studies on oxidative mechanisms of low-intensity RFR (Yakymenko et al., 2015), to those on blood-brain barrier permeability (Nittby et al., 2009), to more (cf. Henry Lai’s summaries of the literature), there is extensive evidence of non-thermal effects of RFR.

I’ve spent a lot of time hearing people’s opinions about EMFs and reading papers, lawsuits, and regulatory filings. There is a ton of room for debate and research on EMFs, their bioeffects, and at what levels and under which circumstances those effects occur. It should be a vibrant area of scientific and regulatory discourse.

But, from my perspective, there is one question on which there should not be meaningful debate anymore: can non-thermal radiofrequency radiation have some sort of biological effects?

From my review of the record, I believe the answer is clearly yes — and so I believe this needs to be accounted for in the regulations of RFR. What those limits should be is a entirely different — and much harder — question. But to continue to put our hands over our eyes and pretend that there are no such effects is, in my estimation, foolish.

As part of addressing this:

  • I’d love to see a new research mandate from the government, particularly prioritizing childhood and prenatal exposure, blood-brain barrier permeability, neurological development, and DNA damage and repair mechanisms.
  • As well as a regulatory modernization, updating the RF exposure guidelines to account for non-thermal effects, cumulative exposure, varied modulation schemes, and childhood exposure.
  • And in order to achieve this, I’d like to see judicial enforcement compelling FCC compliance with the DC Circuit Court’s 2021 remand.

Fingers crossed.

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