Scientific evidence 

The international experts all agree that, taken as a whole, the scientific evidence does not support there being any health effects from radiofrequency transmissions at the levels of exposure we are talking about.

There have been a lot of individual studies performed and published, and it is fair to acknowledge that within that, there have been some that do suggest health effects. You sometimes hear these mentioned and we talk about some of the more important of these below. Because of those individual studies, the issue can't yet be regarded as completely closed and research continues.

But you have to reach an overall judgement from the totality of the evidence, not just from individual studies, and when you look at the totality of the evidence, it does not demonstrate health effects from these exposures. That is the view of the authoritative and independent scientific review bodies that have looked at the issue, and it is these review bodies and their assessments that inform international safe exposure levels. ESB Networks complies with these independent international safety standards.

Radiofrequency exposures have been around since the first public broadcasts started in the early twentieth century. From roughly the 1980s onwards, so for about forty years, there have been additional exposures from mobile phones, Wi-Fi, and various other wireless systems. Possible health effects have been studied extensively over this period, with hundreds if not thousands of studies. It seems highly likely that if there were any adverse health effects, they would have been identified by now, given the large number of studies looking for them.

There are two main types of study we can do. We can look at actual human populations and see if there is any observed link between exposures and any health outcomes. This is called “epidemiology”. One particular type of epidemiological study is to look at the recent decades, when exposure across the population to these transmissions has increased dramatically and see if there has been any corresponding change in the incidence of any diseases.

The other approach is to test for effects in the laboratory. We can expose a whole animal - a mouse or a rat - or specific tissues or cells to artificial exposures, and look for specific effects. One advantage of these studies is that we can make the exposures quite high - higher than humans are exposed to - so as to make it as likely as possible that any effects that might occur actually will be seen.

Epidemiological studies look at actual human populations and whether there is a correlation between exposure and health effects. Overall, the epidemiological studies are reassuring. They do not establish any adverse health effects of radiofrequency exposures.

When we look at incidence rates of, for example, various cancers, and brain cancer in particular, these have generally not shown any signs of increasing in recent years. Mobile phones and other technologies that produce these radiofrequency exposures have been around for long enough (thirty years or so) that if there were any link, we would definitely expect to have seen an increase in incidence rates by now. The fact that we have not is reassuring.

Occasionally, papers get published that do claim to have seen an increase in the incidence of a particular cancer but these have usually picked out just one very specific subtype that happens to show the pattern being looked for. It doesn't change the overall picture that incidence rates are not showing any increase that can be linked to radiofrequency exposures.

There have also been many epidemiological studies looking at exposures from particular sources, usually mobile phones. Do people who use mobile phones more get cancer more often? These are difficult studies to do, because reconstructing accurately how much people used phones many years in the past (and which side of the head they held them on, and whether they used them hands free or not) is notoriously error-prone. But overall, no clear link between exposure and disease has emerged, not even in the closest we have to gold-standard studies. Some studies, for example some studies from a particular research group in Sweden, have reported a possible link, and in the largest international study yet done, called Interphone, there was just a suggestion of a link in certain specific groups. The International Agency for Research on Cancer (IARC) examined these studies thoroughly. IARC concluded that these studies certainly do not establish any link, which is why IARC did not classify radiofrequency exposure either as a definite cause of cancer or even as probably a cause of cancer. But until the issues can be more conclusively resolved, IARC considered there was theoretically still an open question, which is why they classified these exposures as “possibly” a cause of cancer. But all the experts agree the epidemiological evidence is, overall, largely reassuring.

Studies on humans who use mobile phones are important when considering smart meters because the exposures from mobile phones are usually much higher than from smart meters, both because they are typically used much closer to the body, and because the duration of exposure is vastly greater. If no effects have been established with the higher exposures from mobile phones, this is reassuring for the lower exposures from smart meters.

Just as with the epidemiological evidence, there have been many laboratory studies and taken overall, they are reassuring. They do not suggest that exposure to radiofrequencies causes cancer or any other disease. The authoritative independent review groups all agree that there is no adverse health outcome, nor even a possible mechanism, that has been established through laboratory studies.

Of course, with so many studies, there are some that report finding effects. This could be for all sorts of reasons – for example, it could just be chance, or there could be a problem with the way the study was conducted. The key test is whether those effects can then be replicated by other scientists in different laboratories. After all, if an effect is real, any competent scientist with the right equipment ought to be able to observe it. But there is no report of any health effect that has been established by replication in different laboratories. When expert review groups draw conclusions, they virtually never base those conclusions on just a single study. Science works by building on previous results to develop understanding, so expert review groups look at the totality of the evidence. Various independent expert groups agree there are no established health effects of radiofrequency exposures.

One study that has rightly attracted some attention is a recent study on mice and rats by the National Toxicology Program (NTP) in the USA. The studies that NTP conduct (of which this is just one) are big and thorough, so are always taken seriously. This particular study looked at both male and female animals, with multiple levels of exposure and nearly a hundred animals in each group, tested over two years. It found just one tumour type, malignant schwannoma of the heart, that met their criteria for being linked to exposure and that was in male rats only, not females or in mice. Because of the potential importance of this finding, it has been scrutinised carefully, along with another study of rats by a group in Italy. Quite rightly, none of the experts who have looked at it have dismissed it altogether. But equally, the expert review groups don’t find it convincing either. For example, the International Commission on Non-Ionizing Radiation Protection (ICNIRP) said:

“Although the NTP (2018a, b) and Falcioni et al. (2018) studies used large numbers of animals, best laboratory practice and exposed animals for the whole of their lives, consideration of their findings does not provide evidence that radiofrequency EMF is carcinogenic….”

Source

It is worth noting that the mice and rats in the NTP study were exposed at quite a high level - higher, in fact, than is permitted by the exposure limits and certainly much higher than exposures from smart meters.

The nearest thing there is to an official classification of whether any particular agent causes cancer is the Monographs series undertaken by the International Agency for Research on Cancer (IARC, an agency of the World Health Organization). They have classified several hundred different agents over the years, and looked at radiofrequency exposures in 2013.Source.

For both the epidemiological evidence on humans and the animal evidence from the laboratory, they recognised that there are some studies suggesting effects. They didn't think that any of these studies established health effects, so they classified each type of evidence as “limited”, a classification that acknowledges the existence of the studies but suggests caution in placing too much weight on them.

That then leads to an overall classification as “2B” or “possibly a cause of cancer”, again, a classification that acknowledges that the possibility has not been completely ruled out. There is a higher classification, “2A” or “probably a cause of cancer”, and an even higher classification “1” or “established cause of cancer”, and IARC did not consider either of these appropriate, opting for the weaker 2B.

The evidence that led IARC to these classifications mainly related to exposures from mobile phones, which are considerably higher than from smart meters.

We give here the latest statement from the various international authoritative groups:

The International Commission on Non-Ionizing Radiation Protection (ICNIRP)

"The overall evaluation of all the research on HF fields leads to the conclusion that HF exposure below the thermal threshold is unlikely to be associated with adverse health effects.”

Note: “HF” stands for “high frequency”, which includes radiofrequencies

WHO

"A large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established as being caused by mobile phone use."

Note: This statement is specific to mobile phones, but the same conclusion would apply to all radiofrequency exposures.

SCENIHR was the European Union's scientific advisory committee covering EMFs (the EU has subsequently reorganised its scientific committees and the responsibility now lies with a different committee, but the most recent opinion, in 2015, comes from SCENIHR).

"Overall, the epidemiological studies on mobile phone RF EMF exposure do not show an increased risk of brain tumours. Furthermore, they do not indicate an increased risk for other cancers of the head and neck region."

Note: Scientific Committee on Emerging and Newly Identified Health Risks SCENIHR Opinion on Potential health effects of exposure to electromagnetic fields (EMF)[JS3]. This is their conclusion on cancers.

The full report covers other possible health effects with similar conclusions.

If the exposure is high enough, radiofrequencies cause heating of living tissues, and if the heating is great enough, that can certainly be harmful to humans.

It is precisely because radiofrequencies do have clear and well understood effects at high-enough levels that exposure limits to prevent these effects are set. The exposure limits (explained in their own FAQ) are designed to prevent any possibility of heating high enough to have adverse effects of people, and with a big safety margin built in as well.

The expert groups who set the exposure limits looked at all the evidence, relating to all possible effects of radiofrequencies. That includes studies relating to whether radiofrequencies cause cancer as well as the studies on heating. They concluded that heating is a well-established effect that exposure limits can be set to protect against. But they said that the evidence on cancer, for example, was just too weak and inconclusive to allow the setting of exposure limits.

Some people report being particularly sensitive to exposures to electric and magnetic fields, both at mains frequency and at radiofrequencies. They report getting symptoms, sometimes quite severe, such as headaches, nausea, lethargy, insomnia, etc. This is often called “hypersensitivity” or “electrosensitivity”, or the more medical term “idiopathic environmental intolerance”.

The symptoms that these people experience are undoubtedly genuine, and debilitating. But careful, controlled tests have not shown that the symptoms are related to actual exposure. Rather, it may be that it is the perception of exposure - the awareness of the presence of a source of exposure - that triggers the symptoms.

When people report electrosensitivity, it is usually connected to mobile phones, base stations, wifi networks, etc. There are few reports linking any of these symptoms to smart meters.