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….”
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.