Wi-Fi routers and cancer risk: what NCI reports

This page is for anyone worried that the Wi-Fi router in their home could cause cancer. It explains what the National Cancer Institute (NCI) says about this kind of energy.

A Wi-Fi router in your home is not a cancer exposure that the National Cancer Institute treats as a threat. Its fact sheet on electromagnetic fields makes one plain comparison. Radiofrequency radiation exposure from Wi-Fi devices is considerably lower than that from cell phones.

NCI also speaks to the whole category of energy that Wi-Fi belongs to. It reports that no mechanism by which extremely low frequency fields or radiofrequency radiation could cause cancer has been identified.

That point is easy to skim past. So here it is in plainer words. Researchers have not found a way this energy could do the damage that starts a cancer.

The word radiation carries a lot of weight. It covers two very different things.

Ionizing radiation includes x-rays and gamma rays. It carries enough energy to knock electrons loose from atoms. That is how it damages DNA. It is the reason doses from medical imaging are tracked.

Non-ionizing electromagnetic fields are the other kind. They include the extremely low frequency fields from power lines and household appliances. They also include the radiofrequency energy used by wireless devices. Your router lives here. NCI says most Wi-Fi devices operate at frequencies broadly similar to cell phones, typically 2.4 to 2.5 GHz (gigahertz, a unit of frequency). Some newer ones run at 5, 5.3 or 5.8 GHz.

Almost every confused conversation about Wi-Fi starts the same way. People treat these two groups as if they were one.

NCI's summary covers far more ground than routers. The pattern is worth knowing.

For children, NCI concludes that no consistent evidence for an association between any source of non-ionizing EMF and cancer has been found. Power lines are the one place where pooled analyses did find something. A pooled analysis of nine studies reported a twofold increase in childhood leukemia risk among children exposed to magnetic fields of 0.4 microtesla or higher. Less than 1 percent of the children in those studies had exposure at that level, which NCI notes is present in few homes.

For adults, NCI notes that many studies have examined the question. Few have reported evidence of increased risk.

The International Agency for Research on Cancer classified extremely low frequency fields as possibly carcinogenic to humans back in 2002. That rested on limited evidence about childhood leukemia. Static fields were judged not classifiable.

Possibly carcinogenic describes uncertainty in the evidence. It is not a measure of danger.

Wi-Fi is invisible. It is everywhere. And it arrived fast. Those three features are enough to make anything feel suspect. That is truer still when someone is newly frightened by a diagnosis and hunting for the reason it happened.

Some meters claim to detect dangerous levels in a home. This page found no NCI guidance that supports using them.

Does a router in the bedroom keep you awake with anxiety? Moving it costs nothing. Do it if it helps you sleep. NCI does not say it is needed.

Do not let it stand in for steps with stronger evidence. Ask your care team which steps fit you, such as not smoking, limiting alcohol, staying active and keeping up with recommended screening.

Did this question come up because you are trying to make sense of a diagnosis? That is worth saying out loud to your team. Most people never get a satisfying answer to why me. That absence is hard. It deserves better company than a search engine at 2 a.m.