There are plenty of reasons to be concerned about overuse of cellphones: traffic collisions from distracted driving, the rudeness of carrying on private conversations in public places, and for smartphone addicts, social isolation from other human beings. But cancer isn't one of them.

Despite fears that electromagnetic radiation from cellphones puts users at increased risk of cancer, two new studies show those fears are unfounded. The new studies looked at super-high doses of radiation administered to rats and mice — nine hours a day for up to two years at levels normally not encountered by human cellphone users except very briefly and very occasionally.

The studies found no increase in cancer risk in the animals studied, other than a small increase in a rare heart tumor in some male rats, but not in female rats or in mice. And the heart nerve-tissue tumor results do not directly indicate a concern for humans. Bottom line: Cellphones are safe.

If cellphones are safe, then it logically follows that other devices emitting the same kind of radiation at much lower levels are safe, too, right?

Not according to foes of so-called "smart meters" being installed by electric utilities in customers' homes.

Smart meters use cellphone technology to send usage reports to the power company, eliminating the need for a meter reader to come to your house. The technology increases efficiency and can save customers money by alerting them to excessive power usage. The meters also can alert the utility when there is an outage, allowing crews to respond more quickly.

Smart meters emit signals using the same wireless technology as cellphones, but at a much lower wattage, and only in brief bursts. Smart meters also are typically installed on the outside of the house, unlike cellphones and WiFi routers, which operate inside and produce much stronger signals. Smart meters operate at levels far below common household items, including baby monitors and microwave ovens.

There are those who argue that utility companies, the World Health Organization and the Food and Drug Administration are lying about smart meters. But if so, then cellphones, WiFi routers, iPads, cell towers and your microwave oven are damaging your health even now. To avoid all that, one would have to remove all such devices from the home, never allow anyone to bring a cellphone into the home, and never patronize a coffee shop or restaurant, virtually all of which have WiFi and other wireless devices. In fact, it would be wisest never to leave the house at all, given the fact that cell signals are nearly everywhere.

It's possible that the researchers are wrong, and long-term exposure to cell signals and other radiation could turn out to have detrimental effects after, say, 50 years or so. Since becoming a hermit isn't realistic for those of us who have to work for a living, I'm willing to take that risk.