Editor’s note: This article was originally published in April 2015. We’ve updated it at the bottom with new research and information. You can skip to the update by clicking here.
“It’s looking increasingly likely that cellular phones (mostly smartphones these days) are harmful in terms of cancer risk, particularly to the head and neck. A lot of scientists have come around to the view that radiofrequency radiation is probably carcinogenic because of new research that has emerged since 2011.”
That was Joel M. Moskowitz, director of the Center for Family and Community Health, at the University of California at Berkeley.
2011 was the year the World Health Organization’s International Agency for Research on Cancer classified radiofrequency electromagnetic fields as “possibly carcinogenic to humans.
” A panel of 31 expert scientists from 14 different countries concluded radiofrequency radiation, which is emitted by cell phones and other wireless communication devices should be placed in Group 2B alongside a fairly long list of other substances that include lead, coffee, nickel, and gasoline.
But is it really so dangerous? Despite the passionate views espoused by many experts, others are confident the risk is overblown, or at least reluctant to push for sweeping societal changes. Should you be afraid, or gab away as usual? We asked a few experts to find out the truth.
Independent studies are showing the danger
Is Cell Phone Radiation What You Should Be Worried About? – Panda Security Mediacenter
An issue that is brought up time and time again is how cell phones affect the human body. From concerns about when kids should get smartphones to concerns about the impact of too much screen time to claims that cell phones are linked to cancer found in the body, there are many concerns about these devices.
The truth is that while their impact is being studied, these devices haven’t been around for long enough to know what long-term effects they have. That being said, we are able to compare cell phones with other types of radiation in order to gain a better understanding of how they work and what we can do to prevent potential negative effects.
Jump to the infographic.
What is Radiation?
Radiation is a form of electromagnetic energy. All electromagnetic energy falls on the electromagnetic spectrum. There are two types of electromagnetic radiation: ionizing and non-ionizing. On the low end of the spectrum is extremely low frequency (ELF) radiation which is non-ionizing. The opposite side of the spectrum has x-rays and gamma rays which are ionizing.
Where something lies on the electromagnetic spectrum depends on the wavelength’s frequency. The more frequent a wave passes by a certain point, the more radiation it produces.
While radiation has a negative connotation, it’s not necessarily bad. Visible light is an example of electromagnetic radiation that falls in the middle of the spectrum. A problem occurs when humans absorb too much of this energy. For example, laying in direct visible light for too long can cause a burn or even lead to skin cancer.
Frequency is often measured in hertz (Hz) or millihertz (MHz). Using this scale, here is the frequency of radiation in common electronics:
- Airplane radio: 122.75 MHz
- Cell Phones: 450-2000 MHz (most common is about 850 MHz)
- Microwave ovens: 2450 MHz
- Wifi: 2450 MHz
Another way that radiation is measured is through Roentgen equivalent man or rem. Rem or millirem measures the effects radiation has on humans. According to the U.S. Nuclear Regulatory Commission, the average annual dose of radiation per person from natural and man-made sources is 350 mrems.
Mrem for common items:
- Living within 50 miles of a nuclear power plant: 0.0009 mrem
- Using a gas lantern when camping: 0.003 mrem
- Wearing an LCD wristwatch: 0.006 mrem
- Living within 50 miles of a coal-fired electrical utility plant: 0.03 mrem
- Using a video display: 1 mrem
- Watching TV: 1 mrem
- Round trip flight from Los Angeles to New York: 6 mrem
- Chest x-ray: 10 mrem
Cell Phones and Cancer Risk Fact Sheet
There are three main reasons why people are concerned that cell phones (also known as “mobile” or “wireless” telephones) might have the potential to cause certain types of cancer or other health problems:
- Cell phones emit radiofrequency radiation (radio waves), a form of non-ionizing radiation, from their antennas. Parts of the body nearest to the antenna can absorb this energy.
- The number of cell phone users has increased rapidly. There were over 400 million cell phone subscribers in the United States in 2017, according to the Cellular Telecommunications and Internet Association. Globally, there are more than 5 billion cell phone users.
- Over time, the number of cell phone calls per day, the length of each call, and the amount of time people use cell phones have increased. Because of changes in cell phone technology and increases in the number of base stations for transmitting wireless signals, the exposure from cell phone use—power output—has changed, mostly lowered, in many regions of the United States (1).
The NCI fact sheet Electromagnetic Fields and Cancer includes information on wireless local area networks (commonly known as Wi-Fi), cell phone base stations, and cordless telephones.
Radiofrequency radiation is a form of electromagnetic radiation. Electromagnetic radiation can be categorized into two types: ionizing (e.g., x-rays, radon, and cosmic rays) and non-ionizing (e.g.
, radiofrequency and extremely low frequency, or power frequency). Electromagnetic radiation is defined according to its wavelength and frequency, which is the number of cycles of a wave that pass a reference point per second.
Electromagnetic frequencies are described in units called hertz (Hz).
The energy of electromagnetic radiation is determined by its frequency; ionizing radiation is high frequency, and therefore high energy, whereas non-ionizing radiation is low frequency, and therefore low energy. The NCI fact sheet Electromagnetic Fields and Cancer lists sources of radiofrequency radiation. More information about ionizing radiation can be found on the Radiation page.
The frequency of radiofrequency electromagnetic radiation ranges from 30 kilohertz (30 kHz, or 30,000 Hz) to 300 gigahertz (300 GHz, or 300 billion Hz).
Electromagnetic fields in the radiofrequency range are used for telecommunications applications, including cell phones, televisions, and radio transmissions. The human body absorbs energy from devices that emit radiofrequency electromagnetic radiation.
The dose of the absorbed energy is estimated using a measure called the specific absorption rate (SAR), which is expressed in watts per kilogram of body weight.
Exposure to ionizing radiation, such as from x-rays, is known to increase the risk of cancer. However, although many studies have examined the potential health effects of non-ionizing radiation from radar, microwave ovens, cell phones, and other sources, there is currently no consistent evidence that non-ionizing radiation increases cancer risk in humans (2).
The only consistently recognized biological effect of radiofrequency radiation in humans is heating. The ability of microwave ovens to heat food is one example of this effect of radiofrequency radiation.
Radiofrequency exposure from cell phone use does cause heating to the area of the body where a cell phone or other device is held (e.g., the ear and head). However, it is not sufficient to measurably increase body temperature.
There are no other clearly established effects on the human body from radiofrequency radiation.
Epidemiologic studies use information from several sources, including questionnaires and data from cell phone service providers, to estimate radiofrequency radiation exposure. Direct measurements are not yet possible outside of a laboratory setting. Estimates take into account the following:
- How “regularly” study participants use cell phones (the number of calls per week or month)
- The age and the year when study participants first used a cell phone and the age and the year of last use (allows calculation of the duration of use and time since the start of use)
- The average number of cell phone calls per day, week, or month (frequency)
- The average length of a typical cell phone call
- The total hours of lifetime use, calculated from the length of typical call times, the frequency of use, and the duration of use
Researchers have carried out several types of epidemiologic studies in humans to investigate the possibility of a relationship between cell phone use and the risk of malignant (cancerous) brain tumors, such as gliomas, as well as benign (noncancerous) tumors, such as acoustic neuroma (tumors in the cells of the nerve responsible for hearing that are also known as vestibular schwannomas), meningiomas (usually benign tumors in the membranes that cover and protect the brain and spinal cord), and parotid gland tumors (tumors in the salivary glands) (3).
In one type of study, called a case–control study, cell phone use is compared between people with these types of tumors and people without them. In another type of study, called a cohort study, a large group of people who do not have cancer at study entry is followed over time and the rate of these tumors in people who did and didn’t use cell phones is compared.
Cancer incidence data can also be analyzed over time to see if the rates of brain tumors changed in large populations during the time that cell phone use increased dramatically. These studies have not shown clear evidence of a relationship between cell phone use and cancer.
However, researchers have reported some statistically significant associations for certain subgroups of people.
Three large epidemiologic studies have examined the possible association between cell phone use and cancer: Interphone, a case–control study; the Danish Study, a cohort study; and the Million Women Study, another cohort study.
How the study was done: This is the largest health-related case–control study of cell phone use and the risk of head and neck tumors. It was conducted by a consortium of researchers from 13 countries. The data came from questionnaires that were completed by study participants.
What the study showed:
Cell Phones and Radiation
Share on PinterestYour cell phone may be exposing you to more radiation than you thought. Getty Images
- Using accredited lab tests that mimic human tissue, reporters from The Chicago Tribune tested smartphone radiofrequency radiation emitted by 11 models of popular cell phones.
- They found most of the phones exceeded the legal limit set by the FCC of 1.6 watts per kilogram averaged over 1 gram of tissue.
- Radiofrequency radiation exposure from the iPhone 7 — one of the most popular smartphones ever sold — measured over the legal safety limit and more than double what Apple reported to federal regulators from its own testing.
- The FCC is currently investigating the reported findings.
A recent investigation has reignited debate over the safety of cell and smartphones. It’s also spurred class-action lawsuits and has activists calling on federal regulators to reassess the limits of radiation allowed to seep out from radio-emitting mobile devices that are now a part of daily modern life.
The Chicago Tribune recently released findings of its own investigation into radiofrequency radiation emitted by popular smartphones, including several variations of the iPhone.
Overall, Tribune reporters, using accredited lab tests that mimic human tissue, tested 11 models from four companies: Apple, Samsung, Motorola, and BLU.
The Federal Communications Commission (FCC) — which regulates cell phones, among other things, in the United States — has set radiation standards for cell phones at 1.6 watts per kilogram averaged over 1 gram of tissue. Most of the phones the Tribune tested well exceeded that amount at 2 millimeters, or the distance your phone would be in your pocket.
- “Radiofrequency radiation exposure from the iPhone 7 — one of the most popular smartphones ever sold — measured over the legal safety limit and more than double what Apple reported to federal regulators from its own testing,” the Tribune reported.
- Radiofrequency (RF) radiation is of a concern because, according to the FCC, “It has been known for many years that exposure to very high levels of RF radiation can be harmful due to the ability of RF energy to heat biological tissue rapidly.”
Health risks associated with mobile phones use
Mobile or cell phones are now a days an integral part of modern telecommunications in every individual life. In many countries, over half of the population use mobile phones and the mobile phone market is growing rapidly.
Saudi Arabia rank first among the countries of the gulf region with highest proportion of mobile users, a study conducted by United Nations Conference on Trade and Development (UNCTAD). In gulf countries, Oman ranked second, followed by Kuwait and the UAE.
As billions of people use mobile phones globally, a small increase in the incidence of adverse effects on health could have major public health implications on long term basis.
Besides the number of cell phone calls per day, the length of each call and the amount of time people use cell phones are important factors which enhance the health related risk. (1)
Mobile phones emit radiofrequency energy, a form of non-ionizing electromagnetic radiation, which can be absorbed by tissues close to the phone.
The amount of radiofrequency energy a mobile phone user is exposed depend on many factors as the technology of the phone, the distance between the phone and the user, the extent and type of mobile phone use and the user’s distance from cell phone towers. (2)
In 2011, International Agency for Research on Cancer (IARC) classified mobile phone radiation possibly carcinogenic, means that there “could be some risk” of carcinogenicity, so additional research into the long-term, heavy use of mobile phones needs to be conducted. (3)
While an increased risk of brain tumours from the use of mobile phones is not established, the increasing use of mobile phones and the lack of data for mobile phone use over time periods longer than 15 years warrant further research of mobile phone use and brain cancer risk.
In particular, with the recent popularity of mobile phone use among younger people, potentially longer lifetime of exposure, WHO has promoted further research on this group and is currently assessing the health impact of RF fields on all studied endpoints.
A cohort study in Denmark linked billing information from more than 358,000 cell phone subscribers with brain tumour incidence data from the Danish Cancer Registry.
The analyses found no association between cell phone use and the incidence of glioma, meningioma, or acoustic neuroma, even among people who had been cell phone subscribers for 13 or more years. (4)
The American Cancer Society (ACS) states that the IARC classification means that there could be some risk associated with cancer, but the evidence is not strong enough to be considered causal and needs to be investigated further. Individuals who are concerned about radiofrequency exposure can limit their exposure, including using an ear piece and limiting cell phone use, particularly among children. (5)
Scientists have reported adverse health effects of using mobile phones including changes in brain activity, reaction times, and sleep patterns. More studies are underway to try to confirm these findings.
When mobile phones are used very close to some medical devices (including pacemakers, implantable defibrillators, and certain hearing aids) there is the possibility of causing interference with their operation. There is also the potential of interference between mobile phones signals and aircraft electronics.
Some countries have licensed mobile phone use on aircraft during flight using systems that control the phone output power.
Research has shown an increased risk of traffic accidents, about 3–4 times greater chance of an accident, when mobile phones (either handheld or with a “hands-free” kit) are used while driving due to distraction. (6)
Children have the potential to be at greater risk than adults for developing brain cancer from cell phones. Their nervous systems are still developing and therefore more vulnerable to factors that may cause cancer.
The FDA (7) have suggested steps to reduce the exposure to radiofrequency energy:
- Reserve the use of cell phones for shorter conversations or for times when a landline phone is not available.
- Use a hands-free device, which places more distance between the phone and the head of the user.
1. Electromagnetic fields and public health: mobile phones. available at URL: http://www.who.int/mediacentre/factsheets/fs193/en/
New Studies Link Cell Phone Radiation with Cancer
Does cell phone radiation cause cancer? New studies show a correlation in lab rats, but the evidence may not resolve ongoing debates over causality or whether any effects arise in people.
The ionizing radiation given off by sources such as x-ray machines and the sun boosts cancer risk by shredding molecules in the body. But the non-ionizing radio-frequency (RF) radiation that cell phones and other wireless devices emit has just one known biological effect: an ability to heat tissue by exciting its molecules.
Still, evidence advanced by the studies shows prolonged exposure to even very low levels of RF radiation, perhaps by mechanisms other than heating that remain unknown, makes rats uniquely prone to a rare tumor called a schwannoma, which affects a type of neuron (or nerve cell) called a Schwann cell.
The studies are notable for their sizes.
Researchers at the National Toxicology Program, a federal interagency group under the National Institutes of Health, tested 3,000 rats and mice of both sexes for two years—the largest investigation of RF radiation and cancer in rodents ever undertaken in the U.S. European investigators at the Ramazzini Institute in Italy were similarly ambitious; in their recent study they investigated RF effects in nearly 2,500 rats from the fetal stage until death.
Also noteworthy is that the studies evaluated radiation exposures in different ways. The NTP looked at “near-field” exposures, which approximate how people are dosed while using cell phones.
Ramazzini researchers looked at “far-field” exposures, which approximate the wireless RF radiation that bombards us from sources all around us, including wireless devices such as tablet and laptop computers.
Yet they generated comparable results: Male rats in both studies (but not mice or female animals) developed schwannomas of the heart at statistically higher rates than control animals that were not exposed.
Taken together, the findings “confirm that RF radiation exposure has biological effects” in rats, some of them “relevant to carcinogenesis,” says Jon Samet, a professor of preventive medicine and dean of the Colorado School of Public Health, who did not participate in either study. Samet, however, cautioned the jury is still out as to whether wireless technology is similarly risky to people. Indeed, heart schwannomas are exceedingly rare in humans; only a handful of cases have ever been documented in the medical literature.
When turned on, cell phones and other wireless devices emit RF radiation continually, even if they are not being actively used, because they are always communicating with cell towers. The dose intensity tails off with increasing distance from the body, and reaches a maximum when the devices are used next to the head during phone calls or in front of the body during texting or tweeting.
Launched at the U.S. Food and Drug Administration’s request 10 years ago, the NTP study dosed rats and mice of both sexes with RF radiation at either 1.5, 3 or 6 watts of radiation per kilogram of body weight, or W/kg.
The lowest dose is about the same as the Federal Communications Commission’s limit for public exposure from cell phones, which is 1.6 watts W/kg.
The animals were exposed nine hours a day for two years (about the average life span for a rat), and the exposures were cranked up steadily as the animals grew, so the absorbed doses per unit body weight remained constant over time.
Initially leaked in 2016, results from that $25-million study provided the most compelling evidence yet that RF energy may be linked to cancer in lab rodents.
The strongest finding connected RF with heart schwannomas in male rats, but the researchers also reported elevated rates of lymphoma as well as cancers affecting the prostate, skin, lung, liver and brain in the exposed animals.
Rates for those cancers increased as the doses got higher but the evidence linking them with cell phone radiation specifically was weak by comparison, and the researchers could not rule out that they might have increased for reasons other than RF exposure. Paradoxically, the radiation-treated animals also lived longer than the nonexposed controls.
The study results were reviewed by a panel of outside experts during a three-day meeting that ended on March 28. They concluded there was “clear evidence” linking RF radiation with heart schwannomas and “some evidence” linking it to gliomas of the brain. It is now up to the NTP to either accept or reject the reviewer's conclusions. A final report is expected within several months.
Limited to rats only, the Ramazzini study tested three doses expressed as the amount of radiation striking the animal’s bodies: either 5, 25 or 50 volts per meter. The exposure measures therefore differed from the absorbed doses calculated during the NTP study.
But the Ramazzini scientists also converted their measures to W/kg, to show how the doses compared with RF limits for cell phones and cell towers set by the FCC and the International Commission on Non-Ionizing Radiation Protection; they ranged down to a 1,000 times lower.
The exposures began when the rats were fetuses and continued for 19 hours a day until the animals died from natural causes.
As in the NTP study, Ramazzini investigators detected statistically elevated rates of heart schwannomas in male rats at the highest dose.
They also had weaker findings linking RF exposure to cancer of glial cells in the brain, which were limited to females.
Ronald Melnick, a retired NTP toxicologist who designed the NTP study, says a measure of consistency between the two studies is important, because “reproducibility in science increases our confidence in the observed results.”
Just why Schwann and glial cells appear to be targets of cell phone radiation is not clear. David Carpenter, a physician who directs the Institute for Health and the Environment at the University at Albany, S.U.
N.Y., explained the purpose of these cells is to insulate nerve fibers throughout the body. These are electrical systems, so that may be some sort of factor, he wrote in an e-mail. “But this is only speculation.
A few epidemiology studies have reported higher rates of tumors inside the skull among people who use cell phones heavily for 10 years or more.
Of particular concern are benign Schwann cell tumors called acoustic neuromas, which affect nerve cells connecting the inner ear with structures inside the brain. These growths can in some instances progress to malignant cancer with time.
But other studies have found no evidence of acoustic neuromas or brain tumors in heavy cell phone users.
Samet adds a major challenge now would be to draw a biologically relevant connection between acoustic neuromas and other glial tumors in the brains of humans with Schwann tumors in rat hearts. “The mechanism is uncertain,” he says. “There’s a lot of information we still need to fill in.”