Updated 6/2/2011 – The International Agency for Research on Cancer (IARC), a division of the World Health Organization (WHO) has classified cell phones as a possible carcinogen.  This new classification has resulted in a number of alarming news headlines, but the new IARC classification needs to be put into context.  The IARC has not done any new studies, they reviewed a number of scientific studies on cell phones and found inconclusive evidence that warrants some caution.  The IARC did not classify cell phones as probable or known carcinogens.

The IARC defines “group 1” as known carcinogens, “group 2A” as probably carcinogens, and “group 2B” as possible carcinogens.  A full list of substances and their group classification can be found here, and yesterday’s announcement put cell phones in group 2B.  But to put this classification into proper context, we need to look at some other common items that are equally or more carcinogenic.

IARC Group 1 – Known carcinogens

• Tobacco.  After decades of education, everyone knows that tobacco is carcinogenic.
• Sunlight (especially 10AM to 2PM).  Ordinary sunlight includes ultraviolet ionizing radiation which is high enough in energy to alter human DNA.  In 2010, this resulted in 1 million new cases of skin cancer in the United States.  But as with so many things in human health, dangerous substances can be healthy or even essential in small doses.  Ultraviolet radiation is essential to vitamin synthesis in the human body.
• Wood dust.  For wood workers or people who often work with wood, they may not be aware of the fact that wood dust known carcinogen.
• Mineral oils.  This one is probably more surprising as mineral oils are used in baby lotions, cold creams, ointments, cosmetics, and food packaging.

IARC Group 2A – Probable carcinogens

• Diesel engine exhaust
• Art glass
• Frying and emissions from high temperature (cooking)

IARC Group 2B – Possible carcinogens

• Cell phones.  This was just added to this classification, but let’s see what else falls under this classification.
• Pickled vegetables.
• Coffee.  It’s starting to sound like the only way to avoid all possible and known carcinogens is to live in a sealed plastic bag.  But critics of cell phone safety would prefer to compare cell phones to the next scary sounding substance.
• DDT (Dichlorodiphenyltrichloroethane).  Yes we’ve all heard about the evils of DDT and how it should be banned for our safety and the WHO IARC has tried to stop worldwide use of DDT with scary classifications like group 2B.  But the truth of the matter is, there were 50 million preventable deaths from Malaria over the last 25 years because of restrictions on DDT use.  The WHO backed down on their opposition to DDT in 2006 for the sake of stopping Malaria, but the WHO regressed to discouraging DDT in 2009.

Conflicting studies on cell phone safety

There are a number of conflicting studies that show no correlation between cell phones and cancer and other studies that show some correlation.  The wireless association (CTIA), the Federal Communications Commission, and the National Cancer Society favor the studies that found no correlation of cancer and cell phones.  Other groups that are critical of wireless technology favor the studies that found correlation.  The conflicting studies make it very difficult for the public to draw conclusions while the two sides battle it out.

Some like Joel M. Moskowitz, director of the UC Berkeley Center for Family and Community Health argued that the higher quality studies on cell phones found correlation with cancer and that the studies which found no risk were of lower quality.  But that characterization is unreasonable given the fact that those “high quality” studies which found cancer correlation used relatively small samples of populations while the no correlation studies used extremely large samples.  For example, the study from Lennart Hardell finding cancer correlation surveyed 209 cases and 425 controls.  By comparison, a large study in Denmark in 2006 tracked 420,000 people (including 52,000 who used cell phones 10 to 21 years) and found no correlation between cell phones and cancer.

Another large study in 2010 conducted by Interphone (group from 13 heath agencies in the European Union) found no increased risk of cancer with cell phone use.  But Interphone study did find some potentially alarming results that found that tumor patients developed tumors on the same side of their head where they used cell phones, but this does not contradict Interphone’s earlier conclusion of no increased cancer risk.  In other words, there was a correlation in the side of the head that developed tumors but there was no increase in the number of people who developed tumors.  From a risk point of view, it won’t matter which side of the brain develops a tumor.  What is significant is that the rate of tumors and cancer isn’t higher among cell phone users.

Critics charge that the Interphone study is invalid because it showed some positive health effects with cell phone users having fewer incidents of cancer (the Danish study also showed this to some extent).  They charge that the results are absurd because cell phones can’t possibly be beneficial to human health.  But this attitude is highly unscientific because scientists never insist on any particular outcome one way or the other.  Scientists might make predictions but their minds are opened to and even excited about the possibility that their predictions are proven wrong by test data because the results are interesting either way.

It’s also naive to assert that something must be harmful when the world is filled with examples to the contrary.  Ultraviolet radiation which is known to be a deadly carcinogen is an example of a deadly substance having the beneficial and crucial role of human vitamin synthesis.  There is also scientific data to suggest beneficial aspects of cell phone radio waves with mice.  A study in 2010 showed that cell phone exposure can prevent or reverse Alzheimer’s disease in mice.  While that may or may not translate to humans, it is an exciting possibility to study and may shed light on mechanisms that can treat or cure Alzheimer’s in humans.

How precautions can be counterproductive

Most people take the position of caution and that it is better to be safe than sorry, but this attitude often ends up producing the opposite of the desired effect.  For example, the same people who are more worried about cell phones and possible cancer risk oppose cell tower construction.  Yet cell towers are thousands to millions of times weaker in terms of strength of their radio signal compared to cell phones simply because of proximity.  Radio propagation physics dictates that something 1,000 times closer in proximity will be 1,000,000 stronger.  Even if the cell tower is 100 times stronger in transmit power, the cell tower that is 1,000 times further away will be 10,000 times weaker than the cell phone.

The significance of this is that cell phones operating closer to cell towers will require significantly lower transmit power than cell phones operating at a distance or in a location that obstructs radio signals.  And because the power level of a nearby cell phone dwarfs the cell tower, the priority for those who want to minimize cell phone radio frequency exposure is to reduce cell phone transmit power.  The only way to achieve this is to have more cell towers or better yet, have a personal cell tower called a “Femtocell” inside one’s own home.

More cell towers mean lower powered cell towers

The lower cell phone power argument hasn’t convinced all the cell tower detractors because they argue that some people (mostly children) don’t use cell phones and they’re better off living far away from cell towers.  The problem with this logic is that someone’s child or someone who doesn’t use cell phones will invariably live or learn or work near a cell tower.  Having 4 times as many cell towers means that each cell tower can operate at 1/4th the power level not to mention the fact that there will be 4 times as much call capacity and data capacity.  Yet parents often picket near their schools demanding that a cell tower not be put up anywhere near their school. The result is that some cities like San Francisco can boast not approving a single cell tower for a decade.

The level of irrationality is highlighted by the fact that many of those same parents who oppose cell tower often have Wi-Fi base stations at home, work, and school which are hundreds of times more powerful than cell towers because of their closer proximity.  Wi-Fi uses similar radio frequencies as cell towers but there is an even more notable example.  TV broadcast towers are vacating the exact same frequencies (50 to 700 MHz) that will be used for newer LTE 4G cell towers.  Those TV towers have been blasting out millions of watts since the 1950s which is longer than most people have been alive.  The LTE 4G towers will typically be in the sub 100 watt range yet cell tower obstructionists continue to argue that they have not been proven safe.

The problem is that the radio frequency alarmists are not using science to come up with sensible public policy.  They demand laws that set minimal distance guidelines for cell towers when the sensible policy is to set maximum permissible radio frequency exposure which would allow for more distributed and closer proximity low power cell towers.  The FCC already sets maximum radio frequency exposure guidelines but the alarmists have ignored the FCC in favor of irrational policies that force cell phones to operate at the highest transmit power levels.

The FCC has already shown great leadership when they implemented a “shot clock” that would set a time limit for local governments to approve or deny new cell tower applications.  Many local governments set applications on hold for years or even decades to prevent wireless carriers from taking them to court.  But the FCC could do more to promote wireless broadband deployment if they had mandates for local governments.  Some of those local government officials have even asked the FCC to override them so that they don’t have to take the blame from vocal anti cell tower voters.  The FCC already prohibits landlords and home owner associations from banning outdoor TV antennas and it would be extremely helpful if they put an end to cell tower obstruction.  Not only would it improve nationwide wireless deployment, it would reduce radio frequency exposure for everyone.  Unless we are prepared to revert to a pre-technological era, this is the only policy that makes sense.

Some sensible precautions

Even though early results form science as a whole show that cell phones aren’t dangerous, the science isn’t done.  That means sensible precautions and not blind obstructionism of cell towers can be wise.  The easiest way to eliminate over 99% of the cell phone radio wave exposure is to keep the phone a few feet form the head and body by using a wired or wireless Bluetooth headset whenever a person intends to have a prolonged conversation.  Bluetooth headsets also uses the same kinds of radio waves that cell phones use, but it operates at 1000 times lower power levels because it only needs to operate within 10 feet while cell phones have to transmit out to a few miles to reach the cell tower.

Headsets also allow the phone to operate away from the human body and get much better call reception.  The human hands can easily block 20 to 25 dB signal level on the iPhone 4 which means roughly 99% of the signal is lost.  That also forces the phone to operate at much higher radio transmit levels to compensate for the blockage.  There are even more benefits to headsets like the prevention of neck problems or car accidents.

Be aware of the snake oil

Consumers should also be aware of shady snake-oil salesman trying to take advantage of the WHO classification of cell phones as possible carcinogens.  I had the misfortune of debating someone trying to sell a special necklace and a small button to attach onto phones that they claim will eliminate the dangers of cell phones.  These devices also claim to have magical properties of making food taste better or eliminating “negative thoughts”, but it sounds more like they want to eliminate some hundred dollar bills from your wallet.  These devices have no basis in science and if they actually did something to block radio waves, they would render the cell phone inoperable.