 You've probably heard that cell phones could cause cancer. Are we developing cancer from cell phones? The World Health Organization labeled phone radiation possibly carcinogenic in 2011, and there was even a big study in 2016 saying that phone radiation gave cancer to a bunch of rats. So what's the deal? Shouldn't we know by now whether carrying a phone at all times is going to kill us? Well, yes and no. Our current understanding of radio waves says that, in theory, phones shouldn't give you cancer. But we're still doing research to find out whether that's true in practice. I asked John Samet, who reviewed all of this data for the World Health Organization, exactly what's going on. The conclusion was that this kind of radiation is a possible cause of cancer. That means that there's some indication of risk, but not enough to put it up to a higher category which would be probable or definite. It also means the agency didn't find there was no risk. The word radiation sounds really scary, but you shouldn't necessarily be scared by it. The FM radio waves your car picks up? That's radiation. Visible light? Radiation. Phone radiation is similar. The problem is, there's a second type of radiation that actually does harm people. That's what's known as ionizing radiation. So things like x-rays and some ultraviolet light. Ionizing radiation can damage your DNA, which can eventually lead to cancer, according to the American Cancer Society. Phone radiation is non-ionizing, meaning it does not damage your DNA. So if it does cause cancer, it's through some mechanism we don't know about yet. Here the evidence is mixed. If you look at the studies done of cell phone users, they provide an inconclusive answer with some saying possible risk and some saying can't find a risk. I'm not saying there's a public health crisis by any means, but I'm saying there's a very widespread exposure in our society and we should just make sure we understand it. Okay, so what happened with the rats in that study that got cancer after being exposed to phone radiation? Do they prove there's a link? That study from the National Toxicology Program found that the more radio waves rats were hit with, the more incidents of heart and brain cancer turned up. The American Cancer Society said it was a good study that shouldn't be ignored. But there were a lot of quirks in its findings. For instance, the rats that got cancer actually lived longer than the ones that didn't. Also, rats aren't people. More findings came out in early 2018. The Food and Drug Administration said evidence showing a link between phone radiation and cancer remained ambiguous. And the agency concluded that, quote, taken together, all this research has given us the confidence that the current safety limits for cell phone radiation remain acceptable for protecting the public health. Scientists are also looking at the rates of brain cancer. They've been dropping for decades, which could be a good sign. But Samet says it could be another decade or more before the effects of widespread phone radiation actually show up. The trouble is, it's hard to even say what we're measuring when we talk about phone radiation. You're surrounded by phone signals all day long. And right now, you might be in a room filled with Wi-Fi signals. That's all radio frequency radiation. Since I've chaired this panel, I get calls about cell phone towers, wireless water meters. And it just goes on and on. And I think what these questions point to, in 21st century United States, we have more and more devices that are emitting radio frequency, like electromagnetic radiation. And with that rationale, it's very reasonable to say, well, we should find out as much as we can about this. And even if there were a small risk, perhaps a very small risk associated with this kind of exposure, we still have an awful lot of people exposed. For now, you don't need to be alarmed. While scientists haven't ruled out a link between phone radiation and cancer, the evidence suggesting a link is still inconclusive. Samet says if you're worried, there are ways to reduce your exposure, like using a headset. But with radio frequency radiation all around us, it's probably better not to worry too much.