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Medicine

World Health Organization Says Mobile Phones May Cause Cancer 354

Posted by Roblimo
from the we're-surrounded-by-carcinogens dept.
Schiphol writes "A new study by the World Health Organization (WHO) concludes that mobile phone radiation presents a carcinogenic hazard. Are cell phones going to be the new tobacco, then?" This seems to be a new interpretation of a long-tern WHO study of possible cellphone health risks that had "inconclusive results" last May.
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World Health Organization Says Mobile Phones May Cause Cancer

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  • by eldavojohn (898314) * <eldavojohn&gmail,com> on Wednesday June 01, 2011 @08:56AM (#36307090) Journal
    I heard this on NPR and they did a better job of putting this new classification into context (and probably detoothing the newsworthiness). It's classified by the IARC as Group 2B, not even Group 2A. The serious list is Group 1 [wikipedia.org] which indicates they are carcinogenic to humans. Group 2B [wikipedia.org] simply means "possibly carcinogenic to humans."

    I would like to point out that also in Group 2B are Magnetic fields (extremely low frequency), pickled vegetables, coffee, nickel and the occupation of carpentry and joinery. And you know what else? Citrus Red No. 2 which is used to color the oranges you buy in supermarkets.

    So they've put it next to coffee, coinage and food coloring. Why doesn't everyone flip out when things like those are added to Group 2B?
    • by Anonymous Coward on Wednesday June 01, 2011 @09:03AM (#36307158)

      Why doesn't everyone flip out when things like those are added to Group 2B?

      Because those lack the "radiation boogieman".

      • by Lumpy (12016) on Wednesday June 01, 2011 @09:40AM (#36307450) Homepage

        Banananaaaaaaas are Radioactive! AHHHHHHH! AAAARRRGGHHHHHHH!!!!!

        Yup, humans are idiots.

      • Disco Stu would like to know more of this "radiation boogieman".

    • by CRCulver (715279) <crculver@christopherculver.com> on Wednesday June 01, 2011 @09:05AM (#36307180) Homepage

      Citrus Red No. 2 which is used to color the oranges you buy in supermarkets.

      Why the fuck do oranges have to be coloured? Are oranges not sufficiently orange?

      • by mikael_j (106439)

        Well, they would be if they were locally produced and harvested at just the right time. But when you factor in harvesting just a little too early, packaging in an inert atmosphere, shipping around the world and then taking another few days to get distributed to the store...

        • by Kokuyo (549451)

          O tempora, o mores!

      • by eldavojohn (898314) * <eldavojohn&gmail,com> on Wednesday June 01, 2011 @09:11AM (#36307198) Journal

        Citrus Red No. 2 which is used to color the oranges you buy in supermarkets.

        Why the fuck do oranges have to be coloured? Are oranges not sufficiently orange?

        Because oranges aren't always orange and they have imperfections. Shipping and storing only exacerbates this. But suppliers noticed that people bought more oranges when they looked "pure" orange. And the FDA allowed it [fda.gov] (for whatever reason). Go to an organic food store sometime and look at the produce. You'll think it looks like shit. But it's really just not coated in dye.

        Oh, but if the big bad evil government stopped oranges getting coated with food dye then everyone would complain that the nanny state is killing capitalism. So vote with your dollar and be lost in the sea of people who put perception above knowledge.

        • by JTsyo (1338447)
          Doesn't the dye just stay on the skin? Does it defuse to the center?
        • by bws111 (1216812)

          What 'knowledge' do you use to tell if an orange is a good one to buy or not? How it feels (perception)? How it smells (perception)? How it looks - bruises, etc (perception)? Or do you just buy any old orange, secure in your knowledge that they are all exactly the same, and there is no such thing as under-ripe, over-ripe, damaged, rotten, etc?

          Personally, if given the choice between oranges that are dyed and oranges that cost twice as much because half of them won't be sold, I'll stick with the dye.

          • It's not because half won't be sold, but because less (none?) pesticides are used more of the crop is lost. Also, non GMO crops yield less than regular crops. They are more likely to spoil in transit or on shelves. If all farms switched to "organic" (God I hate that term) foods millions more people would starve.

          • An under-ripe dyed orange looks like a ripe dyed orange
            An over-ripe dyed orange looks like a ripe dyed orange
            An bruised dyed orange looks like a ripe dyed orange

            I would prefer to buy an orange I can see is ripe, and undamaged ....

        • by Twinbee (767046)

          If it wasn't for the dye, would more strongly orange-coloured oranges taste better on the average?

      • by Lumpy (12016)

        You should read up on what they do to other foods. the ONLY place you can get real food is the farmers market from a small grower (not the mexican in his truck with mangoes and kiwi fruit, that's all supermarket seconds) that is foods that are grown locally. Anything else has been processed... yes even the lettuce in winter.

    • Because it's the WHO. Among some people, they will not ignore what the WHO has said. It's sort of like the Pope giving his blessing or warning.

    • What I find most interesting, is that Lead, used to shield you from harmful X-rays, is also on that list. This means that you couldn't make some sort of lead shielding to protect you from your mobile phone.

      • by Lumpy (12016)

        Why lead? My phones don't emit beta and gamma radiation... Where the hell are you getting your cellphones? The corner dealer in Chernobyl?

        • by blincoln (592401)

          "Why lead? My phones don't emit beta and gamma radiation... Where the hell are you getting your cellphones? The corner dealer in Chernobyl?"

          I think you're on to something with the "gamma radiation cellphone" concept. No more signal loss just because you're in the middle of downtown!

    • by Shikaku (1129753)

      Did you know that America and practically every first world country ships and sells a more dangerous radioactive substance as food? They have much more radiation than coffee, and this substance is even fed to some animals, especially monkeys.

      Hint: bananas have more radiation than almost every other food available, yet nobody wants to pull bananas from the market because it's the only good source of potassium.
      Double hint: you get the same amount of radiation from a banana by just lying near someone.
      Triple h

      • Re: (Score:3, Funny)

        by Anonymous Coward

        Quadruple hint: Taking everything with a grain of salt will increase your sodium intake which is bad, so don't use hints, they will kill you!

      • [...]

        Hint: bananas have more radiation than almost every other food available, yet nobody wants to pull bananas from the market because it's the only good source of potassium.
        Double hint: you get the same amount of radiation from a banana by just lying near someone.
        Triple hint: take everything you read with a grain of iodized salt.

        FTFY

      • by ArsonSmith (13997)

        Salt may not be highly radioactive, but it does have other health implications. I'd suggest skipping the grain per read item rule. Especially for heavy readers.

    • by Punko (784684)
      Just note, the data used with respect to cell phone usage was less than 40 minutes per day. Yes, the base data is that old. How much do folks use there phones now ?
      • by vegiVamp (518171)

        Uhh... on average? probably not ten minutes.

        It *is* in a carrier on my belt, though, so while I'm probably safe from brain cancer I'm gonna be needing a new, non-glowing hip at some point.

    • So they've put it next to coffee, coinage and food coloring. Why doesn't everyone flip out when things like those are added to Group 2B?

      You know what else is in Group 2B?! Gasoline! Gasoline causes cancer! OMG we have to get off gasoline NOW!

      Seriously though, the quote I took from that same Wikipedia article was "[...] less than sufficient evidence of carcinogenicity in experimental animals." In other words, if you take "science says it can't prove god exists" as "science says god might exist", then yes the headline is correct.

    • "Why doesn't everyone flip out when things like those are added to Group 2B"

      Because there is a large group of people who are afraid of science and technology. And they base their knowledge of science on what they learned in 8th grade science class. When they talk about the evils of DDT, and how we didn't know how harmful radiation was when we drop the Atomic bomb to end World War II. So they will go out and protest any technology and use any bit of evidence that it could be harmful to raise their arms us a

    • by cyn1c77 (928549)

      Group 2B [wikipedia.org] simply means "possibly carcinogenic to humans." I would like to point out that also in Group 2B are Magnetic fields (extremely low frequency), pickled vegetables, coffee, nickel and the occupation of carpentry and joinery. And you know what else? Citrus Red No. 2 which is used to color the oranges you buy in supermarkets. So they've put it next to coffee, coinage and food coloring. Why doesn't everyone flip out when things like those are added to Group 2B?

      Your post had me feeling good until I clicked on the Group 2B link and saw nasty materials like lead, DDT, heavy hydrocarbons, and hydrazine.

    • by mr1911 (1942298)
      Take your logic and go home. Can't you see I'm in a frenzied panic here?

      Why doesn't everyone flip out when things like those are added to Group 2B?

      Because the WHO didn't make a big deal about adding those to the list. This is another mostly useless organization throwing FUD around trying to look relevant instead of focusing on the small part of what they do that is actually relevant. Pretty much status quo.

    • It's based off yet another metastudy. No new data, the studies, other than the BMJ study that pretty much everyone has problems with, all still show no causal link. I can't quite figure out the WHO's justification on this one.

  • by robbak (775424) on Wednesday June 01, 2011 @09:00AM (#36307114) Homepage

    Real story: the WHO lacked the guts to put this cellphone nonsense to bed once and for all. Studies that ask people with brain cancers "How much did you use your phone?" are pretty much all they had, and they seem to be the definition of "Confirmation Bias."

    In other news, the media fails science forever, but we knew that already.

    • by Shadowmist (57488) on Wednesday June 01, 2011 @09:12AM (#36307210)

      Real story: the WHO lacked the guts to put this cellphone nonsense to bed once and for all. Studies that ask people with brain cancers "How much did you use your phone?" are pretty much all they had, and they seem to be the definition of "Confirmation Bias."

      In other news, the media fails science forever, but we knew that already.

      I think they did put in a bit more effort than that. low level EMF radiation is not a trivial issue. And if you read the reports instead of concentrating on being shrill they did identify particular groups at risk, such as infants whose parents use cellphone music to keep their toddlers quiet and basically park an active phone next to young developing skulls and brains for hours on end. It also depended a lot on shape, Many flip phones because of their geometry kept the radiating part sufficiently away to be much less a concern, but almsot all smartphones today are unibody designs which means the EMF emitting body and screen is in direct contact with your head.

      • Yeah but is there any evidence at all that low level EMF radiation is bad for you or anyone?

        • by toppavak (943659) on Wednesday June 01, 2011 @09:50AM (#36307592)
          The problem is that the evidence goes both ways, some studies show a correlation, others don't. Keep in mind that what's been said by the WHO isn't that the studies that showed a correlation are correct, just that they might be. The end result for the WHO is to say "well, there *might* be a link so we should at least continue to watch the issue" which is basically all that classifying cell phones as class 2B carcinogens says. As noted by other commentors, this class of potential carcinogen includes things like caffeine, nickel and Red No. 2 food coloring. Basically the slightly misleading name of the category (calling it a carcinogen) has the media all in a tizzy since of course journalists never actually read the quotes they're relaying or look into what that pesky 2B in front means.
          FTFA:

          "This IARC classification does not mean cell phones cause cancer. Under IARC rules, limited evidence from statistical studies can be found even though bias and other data flaws may be the basis for the results."

      • Are you aware that incandescent lightbulbs give off intense radiation between 400 and 700nm, and that often these devices are used in the vicinity of growing infants? And that this radiation is far more energetic than radio emissions? Oh the humanity.

        Still noone has offered up any clue as to how this effect could possibly work when the only biological effects of radio emissions seem to be thermal in nature. Not that if we had some brand new study showing a strong correlation that wouldnt be worth looking

        • And that's the problem here. What's needed isn't yet another metastudy that provides no new data, and ultimately no new insights. What's needed is research. Come back with possible mechanisms, with some solid evidence that there is a link, and then we can all talk about it.

      • by bcrowell (177657)

        I think they did put in a bit more effort than that. low level EMF radiation is not a trivial issue. And if you read the reports instead of concentrating on being shrill they did identify particular groups at risk, such as infants whose parents use cellphone music to keep their toddlers quiet and basically park an active phone next to young developing skulls and brains for hours on end. It also depended a lot on shape, Many flip phones because of their geometry kept the radiating part sufficiently away to be much less a concern, but almsot all smartphones today are unibody designs which means the EMF emitting body and screen is in direct contact with your head.

        All of this is irrelevant, because radio waves are nonionizing radiation.

    • Re: (Score:2, Offtopic)

      by frozentier (1542099)

      Studies that ask people with brain cancers "How much did you use your phone?" are pretty much all they had, and they seem to be the definition of "Confirmation Bias."

      Exactly, and if they had asked 10,000 people with colon cancer how much they used THEIR cell phones, the answer would have probably been "all the time". ANYTHING in the environment could be causing brain tumors: TV use, microwave use, silk pillowcases, dandruff shampoo... As I walk and drive around town, I see everyone using cell phones. I use one, all my family and friends use them. So why aren't people dropping dead left and right from brain tumors?

      • Microwaves arent terribly likely to cause cancer either. They heat things up, and can potentially cause electric arcing between metals, but theyre certainly not ionizing.

      • by Lumpy (12016)

        Therefore toilets cause colon cancer!

        100% of all colon cancer victims use a toilet on a daily basis!

    • by Knutsi (959723)
      I'm not sure that is the question studies have asked. There is difference between asking "have you ever owned a cellphone" and "how much did you use it?". If you can confirm that heavy users get more gliablastomas, you have an interesting correlation - a dose-response relationship. Its perfectly valid to look at people's past in retrospect to see if there has been an exposure that might relate to the condition.
    • by Hatta (162192)

      "Lacked the guts" is a charitable way of putting it. The WHO has lied about the statistical significance of e.g. second hand smoking risk in the past. They are likely to be similarly disingenuous in the future.

  • This announcement will certainly bring out the paranoid reply of the masses... It doesn't really change what any of us "know" about possible cancer causing effects (or lack thereof). But let's be clear... This means that there is a "possibility" that it could contribute to cancer. The WHO has a whole range of classifications within this category that it still really means nothing.

    As an example, other things on this list:
    coffee
    alcoholic drinks
    working the night shift

  • by MMC Monster (602931) on Wednesday June 01, 2011 @09:12AM (#36307216)

    FYI: Also on the list:
    Coffee
    Pickles

  • by Knutsi (959723) on Wednesday June 01, 2011 @09:16AM (#36307246)
    If the radiation from phones (or wireless for that matter) are carcinogenic somehow, should we not see a dramatic increase in cancer incidences in people who suffer from broken DNA-repair mechanisms? Is this being observed?
    • If the radiation from phones (or wireless for that matter) are carcinogenic somehow, should we not see a dramatic increase in cancer incidences in people who suffer from broken DNA-repair mechanisms? Is this being observed?

      Not to validate the fear-mongering going on here, but your question points out the problem we face exactly.

      Perhaps it takes 25 years for cellphone radiation to make any observable changes in somebody's physiology. That would mean that most of the older generation wouldn't even notice a difference in their lives. But it also means that we currently have two entire generations that will all develop brain cancer around age 30. I imagine that would be a touch devastating to the first world countries.

      Every ki

      • by Knutsi (959723) on Wednesday June 01, 2011 @09:56AM (#36307650)
        As far as I understand the mechanisms though, the reason cancer develops over time is that a certain number of mutations have to occur (5-7) for the cells to show hyperplasia, mutator phenotype etc. and eventually metastasize. But in people who lack one or more DNA repair mechanisms, cancer will arise sooner, since the risk (and thus rate) of the mutation is greater (they are not supposed to ever get an X-ray, e.g., or develop breast cancer at a young age. People with xerodema pigmentosum is a example, and they get all sorts of skin cancers eve as children - but you might not want to google that). So I'm asking if there should not be vanguard of sorts, a group of people in which we could detect this. If they have an already identified condition, it might be possible to see that they are getting allot of cancers since cellphones became commonplace.
        • As far as I understand, you are correct.

          I suppose I should have prefaced my argument by saying that it might not even be cancer we need to worry about. We know that cell phone radiation does affect the brain (see: http://slashdot.org/story/06/06/26/1151231/Cell-Phone-Radiation-Excites-the-Brain [slashdot.org]) but we don't know the hows or the whys. Hell, this effect might even be 100% beneficial to humans and have no side effects. It just seems to me that we might be dressing our kids in asbestos clothing; we only kno

      • But it also means that we currently have two entire generations that will all develop brain cancer around age 30. I imagine that would be a touch devastating to the first world countries.

        Not really. It sounds like a selection process to me. It's easy to fall into the habit of thinking 'fuck off and die' when you see people driving or walking with a cellphone wedged permanently to their face.

        There will be a certain amount of satisfaction in seeing cancer wards filled with that sort of people. I wonder if

      • by pyrr (1170465) on Wednesday June 01, 2011 @01:41PM (#36310226)

        But that's not how cancers work. Every time you're exposed to a carcinogen, there's a probability that it will cause damage to your DNA relative to its carcinogenic properties. There's a range of damage it can potentially do. There's a chance that the damage will be repaired. There's a chance that the damage won't really amount to anything, but it might also prove to be malignant. Roll all these probabilities together, but wind-up being pretty unlucky, you get life-threatening, malignant cancer. Carcinogens aren't really cumulative-damage sorts of things; you could chain-smoke for 50 years and not get lung cancer (in which case you'd probably be beating the odds in a death-defying manner), or you could possibly be unlucky enough to have some toxic particulate act on your lung tissue and start a cancer from one whiff of secondhand smoke when you're 5 years old. Every single exposure is a roll of the dice, with one of the static multipliers being the exposure's potential for causing damage to DNA. If that probability is "0", it doesn't matter how many times you roll the dice, you cannot get cancer from that exposure, period.

        That leaves the only question, "What is the potential mechanism for radio waves to damage DNA?" There could be some element we don't understand, but from what we do understand, there is essentially zero chance that the radio transmitters in mobile phones can damage DNA in the skin of your ears, much less your brain cells. If it *could* be demonstrably proven to cause damage to any DNA, then there might be cause for concern. But there is no evidence at all to support such suppositions.

  • Use a headset (Score:2, Interesting)

    by MrKaos (858439)
    I don't think it's that complicated really. 15 years of mobile phone use and I've rarely put a mobile phone near my head not because of fear but because of caution. At first I just wanted a headset so I could keep two hands on the wheel of my car, so in a sense it was a safety issue to begin with.

    With a little research in to understanding how these devices worked from an electronics perspective I discovered that a mobile phone frequency transmits between 900Mhz and 2400Mhz. A rough calculation revealed th

  • If you are going to use that criteria.

  • by Anonymous Coward on Wednesday June 01, 2011 @09:29AM (#36307362)

    Polycarbonate, the plastic used in most cellphones, out-gas various chemicals some of which are known carcinogens. These include benzene, toluene, and chlorobenzene. Since you usually hold the phone up to your face I would bet that you breath enough of this in to cause the amount of cancer found in any study. Real research is done with a negative control for a reason. Since, there is so much radio waves all around us, there is no where that you can exist without the presence of them. Not only that, there is no way for any EM of the wavelength (> than 1 M) or frequency to cause damage to any tissue. The microwave frequency can but it's wavelength is 10 cm and only interacts with molecules on the vibrational frequency that gets absorbed and converted into heat.

  • by Anonymous Coward

    Claiming that cell phones can cause cancer is like saying that the wake from a surfboard could capsize a passing supertanker.

    (And the orders of magnitude in this analogy are not exaggerated. The long-wavelength photons emitted by cell phones would need to be millions of times more energetic to break a peptide bond.)

  • Perspective (Score:4, Interesting)

    by roachdabug (1198259) on Wednesday June 01, 2011 @09:40AM (#36307452)

    According to the report there was a 40% increased chance of glioma among the heaviest cell phone users. According to wikipedia, glioma affects approximately 2-3 in 100,000 people. That's a 0.0025% chance. A 40% increase means cell phone users now have a 0.0035% chance, or 3-4 out of 100,000. You're still 3 times as likely to get hit by lightning and 250 times as likely to die in a fiery car crash.

    • by MadKeithV (102058)

      You're still 3 times as likely to get hit by lightning and 250 times as likely to die in a fiery car crash.

      Except if you're on the phone while driving.

  • by rossdee (243626) on Wednesday June 01, 2011 @09:40AM (#36307464)

    That Daleks and Sonic Screwdrivers may cause cancer

  • by jitterman (987991) on Wednesday June 01, 2011 @09:41AM (#36307472)
    ...somebody said something might possibly do something.

    Way to come out with a definitive conclusion there, WHO.
  • The actual article description of "could possibly cause cancer", is very different from "concludes that mobile phone radiation presents a carcinogenic hazard".

    As others have mentioned, we do and eat many things that have a higher chance of causing cancer than cell phones such as engine exhaust! Should we go on and ban cars now?

  • What the WHO says "There is no evidence that mobile phones cause cancer, but there is also no conclusive evidence that they do not." What CNN reports "There is mounting evidence that cellphones may cause cancer, says the WHO. Cellphones emit non-ionizing radiation, previously thought to not cause cellular damage. Cellphone radiation is similar to microwaves, so it will heat your brain to the boiling point. Some say there is no way that cooking your brain cannot cause some form of harm." Holy hell. I b
  • by argStyopa (232550) on Wednesday June 01, 2011 @10:25AM (#36307954) Journal

    It also says it may NOT be carcinogenic.

    All the studies are inconclusive one way or another, but the bulk of studies seem to be against the idea that they are carcinogenic. Limited (I believe ONE) studies did show an increase in a lethal form of brain cancer, but no other studies supported this.

    So they are probably not carcinogenic, but the bureaucrats are too testicularly-impaired to actually come out and say that, so they leave it at a "may be harmful" rating the same as a bunch of other meaninglessly-"dangerous" things like copper or being a carpenter.

  • by Idarubicin (579475) <allsquietNO@SPAMhotmail.com> on Wednesday June 01, 2011 @11:46AM (#36308950) Journal

    Are cell phones going to be the new tobacco, then?

    No.

    Duh.

    If cell phones were anywhere near as bad as tobacco - or even anywhere near as bad as the doomsayers insist - then the extensive, large-scale, costly, long-term studies already conducted would have picked up a clear effect already.

    Detecting the negative health effects of tobacco was some pretty low-hanging epidemiological fruit. Smokers die between ten and fifteen years younger than their non-smoking peers. Between one half and two thirds will die from a smoking-related illness. Their risk of lung cancer is elevated more than tenfold; about one in six smokers will be killed by it.

    For cellular phones, the absolute worst-case scenario is a statistically-significant increase in the risk of certain rare cancers, affecting a minuscule portion of the population. The WHO's caution is based principally on a single study that found a 40% increase in glioma incidence among heavy cell phone users; the WHO report noted that while there is reason for suspicion, chance or coincidence couldn't be ruled out as a cause of the apparent effect.

    The incidence of central nervous system tumors is something like 7 per 100,000 population per year; gliomas are about half of that total [wiley.com]. If we assume that the full 40% increase in risk is real and accurate, then we're looking at something like 1 or 2 cases per 100,000 population per year. This isn't the next tobacco. This isn't tobacco's kid brother. This isn't even tobacco's fifth cousin's hamster. Heavy cell phone use is something like a thousand-fold less risky than lighting up.

    You're more likely to be killed [purewatergazette.net] by a car (either as a pedestrian or as an occupant), or drowning, or accidental poisoning. You're appreciably more likely to be shot and killed (though slightly less likely to be stabbed to death). Statistically speaking, the average American is quite a bit more likely to deliberately kill himself rather than wait for his cell phone to do it for him.

    The most likely way for cell phone use to kill or maim anyone isn't through radiation, but through distracted driving.

  • by Sipper (462582) on Wednesday June 01, 2011 @12:07PM (#36309174)

    Cell phones cannot cause cancer.

    The reason is that the frequencies cell phones use are below the spectrum of ultraviolet light. It is near the spectrum of ultraviolet light where the first ionizing radiation occurs, which is required to be able to cause cancer. Ionizing means that the energy level of the individual photons of the transmission have enough energy to disturb the molecular structure of live cells. Microwave "radiation" (which has absolutely nothing to do with nuclear radiation) is far within the level of the non-ionizing radiation spectrum, so there is no possibility of it having the energy required to cause cancer.

    Cell phones use frequencies around 800 MHz to around 2 GHz or so. 3 GHz has an energy level of about 12.4 ueV; ultraviolet light where the first ionizing radiation is possible is around 124ev -- that's a 10 million to one difference in energy level. Have a look at the energy level chart on the right hand side of:

    http://en.wikipedia.org/wiki/Electromagnetic_spectrum [wikipedia.org]

    or even better, see page 3 of FCC OET Bulletin 56, which is a Q&A on Biological Effects and Potential Hazards of Radiofrequency Electromagnetic Fields:

    http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet56/oet56e4.pdf [fcc.gov]

    People are also afraid of the cell base stations, because they don't know how safe they actually are. The transmitters for these typically send 20 - 40 watts -- that's all. This is then sent through directional "sectored" antennas that typically have 120 degrees of horizontal beam width and only 6 to 15 degrees of vertical beam width; so the three-dimensional antenna pattern is like a 120 degree slice of a pancake, yielding gain of about 13 dBi. This focusing is where the "gain" of antennas comes from -- by focusing where the energy is transmitted.

    In the U.S., the standard for specifically what frequencies and power levels are considered safe is the IEEE C95.1 standard, which is unfortunately not freely available, however there's a an overview here: http://www.interferencetechnology.com/uploads/media/AG_07.pdf [interferen...nology.com]

    This standard is incredibly long to read, but boils down to this: the only proven effect of microwave radiation in 60 years of research is the effect of microwave heating. No cancer. Further than that, the standard narrows down to the power levels that are safe for various frequency regions concerning microwave heating.

    But if you really want something to "bite your teeth on", have a look at the international ICNIRP guidelines: http://www.icnirp.de/documents/emfgdl.pdf [icnirp.de]

    Now, if you go through the MATH of how close you have to be to the antennas of a cell tower for it to be "unsafe", the result is pretty interesting:

    Spec limit for human-absorbed power per IEEE C95-1 at 900 MHz: 50 Watts/m^2
    13 dBi gain = gain of 20
    EIRP = 20 W transmitted power * gain of 20 = 400 W
    400 W / 4*pi*R^2 = 50 W/m^2
    R = 0.636 meters
    0.636 meters = 2.09 feet

    So at 900 MHz and with a typical transmit power of 20 Watts and a sectored antenna with 13 dBi gain, you need to be 2 feet in front of the antenna while it's transmitting for it to be considered unsafe. This means the only way it's unsafe for a human being is if they're not only on the tower, but right in front of the antenna while it's operating at full power.

    The cell phones themselves have a limit on how much power they are allowed to transmit. There are different power limits in various countries; in the U.S. the limit is 1.6 W/kg SAR, in Canada I believe t

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