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National & International Organization Information on Radio Frequency Safety
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National Institute of Environmental Health of the National Institutes of Health
Question: A cellular communications tower was recently built near my home. Does this present a risk I should be worried about?
Answer: These cellular towers are the base stations for the cells that make up the coverage area for a cellular telephone network. Most of these towers are 50 to 200 ft tall with an antenna mounted on top. These antennas emit radiofrequency electromagnetic waves but at a level much lower than those associated with commercial radio and television stations. The radiofrequency energy these cellular antennas radiate has a power level similar to the energy emitted by common household light bulbs. The strength of these electromagnetic fields (EMFs) decreases rapidly with distance from the antennas and the exposures usually occur hundreds of feet away. In some locations around these facilities, the strength of these fields can decrease to almost undetectable levels at the site property line. Even the peak levels seen are thousands of times lower than the limits set for human exposure to radiofrequency EMFs.
While the biological effects of exposure to much higher intensity radiofrequency fields have been somewhat determined, there is research presently underway to delineate what possible biological effects, if any, are linked to the low intensity exposures near cellular towers. Currently, there is no significant indication that chronic exposure to the EMFs around cellular sites has any potential to be hazardous to human health.
National Radiological Protection Board (NRPB)
There are many sources of RF fields – at work, at home, and in the environment – but recent emphasis in health-related studies has been on mobile phones and broadcasting masts. Studies reviewed by IEGMP suggested possible cognitive effects of exposure to RF fields from mobile phones, and possible effects of pulse modulated RF fields on calcium efflux from the nervous system. The overall evidence on cognitive effects remains inconclusive, while the suggestions of effects on calcium efflux have not been supported by more recent, better-conducted studies. The biological evidence suggests that RF fields do not cause mutation or initiate or promote tumor formation, and the epidemiological data overall do not suggest causal associations between exposures to RF fields, in particular from mobile phone use, and the risk of cancer. Exposure levels from living near to mobile phone base stations are extremely low, and the overall evidence indicates that they are unlikely to pose a risk to health. Little has been published specifically on childhood exposures to RF fields, and no new substantial studies on this have been published since the IEGMP report.
In aggregate the research published since the IEGMP report does not give cause for concern. The weight of evidence now available does not suggest that there are adverse health effects from exposures to RF fields below guideline levels, but the published research on RF exposures and health has limitations, and mobile phones have only been in widespread use for a relatively short time. The possibility therefore remains open that there could be health effects from exposure to RF fields below guideline levels; hence continued research is needed.
Food and Drug Administration
FDA agrees with the NRPB on its conclusions that there is "no hard evidence of adverse health effects on the general public " from exposure to radiofrequency energy while using wireless communication devices. A few studies have suggested low levels of radiofrequency energy exposure could accelerate the development of cancer in laboratory animals, however these studies have failed to be replicated and the vast majority of studies reported in the scientific literature show no adverse heath effect associated with low levels of radio frequency energy exposure. FDA is working with the National toxicology program, the wireless telecommunication industry, other federal agencies and WHO to ensure needed research is conducted investigating the possible health effects of low levels of radio frequency energy. With regards to the safety and use of cell phones by children, the scientific evidence does not show a danger to users of wireless communication devices including children.
Federal Communications Commission (FCC)
FCC rules require transmitting facilities to comply with RF exposure guidelines. The limits established in the guidelines are designed to protect the public health with a very large margin of safety. These limits have been endorsed by federal health and safety agencies such as the Environmental Protection Agency and the Food and Drug Administration. The FCC’s rules have been upheld by a Federal Court of Appeals.[1] As discussed below, most facilities create maximum exposures that are only a small fraction of the limits. Moreover, the limits themselves are many times below levels that are generally accepted as having the potential to cause adverse health effects.
WHAT BIOLOGICAL EFFECTS CAN BE CAUSED BY RF ENERGY?
Biological effects can result from animal or human exposure to RF energy. Biological effects that result from heating of tissue by RF energy are often referred to as "thermal" effects. 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. This is the principle by which microwave ovens cook food. Exposure to very high RF intensities can result in heating of biological tissue and an increase in body temperature. Tissue damage in humans could occur during exposure to high RF levels because of the body's inability to cope with or dissipate the excessive heat that could be generated. Two areas of the body, the eyes and the testes, are particularly vulnerable to RF heating because of the relative lack of available blood flow to dissipate the excessive heat load.
At relatively low levels of exposure to RF radiation, i.e., levels lower than those that would produce significant heating, the evidence for production of harmful biological effects is ambiguous and unproven. Such effects have sometimes been referred to as "non-thermal" effects. Several years ago research reports began appearing in the scientific literature describing the observation of a range of low-level biological effects. However, in many cases further experimental research has been unable to reproduce these effects. Furthermore, there has been no determination that such effects constitute a human health hazard. It is generally agreed that further research is needed to determine the generality of such effects and their possible relevance, if any, to human health. In the meantime, standards-setting organizations and government agencies continue to monitor the latest experimental findings to confirm their validity and determine whether changes in safety limits are needed to protect human health.
World Health Organization
Conclusions
from scientific research
In the area of biological effects and medical applications of non-ionizing
radiation approximately 25,000 articles have been published over the past 30
years. Despite the feeling of some people that more research needs to be done,
scientific knowledge in this area is now more extensive than for most chemicals.
Based on a recent in-depth review of the scientific literature, the WHO
concluded that current evidence does not confirm the existence of any health
consequences from exposure to low level electromagnetic fields. However, some
gaps in knowledge about biological effects exist and need further research.
Effects on
general health
Some members of the public have attributed a diffuse collection of symptoms to
low levels of exposure to electromagnetic fields at home. Reported symptoms
include headaches, anxiety, suicide and depression, nausea, fatigue and loss of
libido. To date, scientific evidence does not support a link between these
symptoms and exposure to electromagnetic fields. At least some of these health
problems may be caused by noise or other factors in the environment, or by
anxiety related to the presence of new technologies.
International Commission for Non-Ionizing Radiation Protection
We have undertaken a comprehensive review of epidemiologic studies about the effects of radiofrequency fields (RF) on human health in order to summarize the current state of knowledge, explain the methodological issues that are involved, and aid in the planning of future studies. There have been a large number of occupational studies over several decades, particularly on cancer, cardiovascular disease, adverse reproductive outcome, and cataract, in relation to RF exposure. More recently, there have been studies of residential exposure, mainly from radio and television transmitters, and especially focusing on leukemia. There have also been studies of mobile telephone users, particularly on brain tumors and less often on other cancers and on symptoms. Results of these studies to date give no consistent or convincing evidence of a casual relation between RF exposure and any adverse health effect. On the other hand, the studies have too many deficiencies to rule out an association. A key concern across all studies is the quality of assessment of RF exposure.
The research on community exposures to RF’s and cancer gives a very weak test of the possibility of a relation. Diverse exposure sources, poorly estimated population exposures, small numbers of cases, and selective investigation in response to cluster concerns have resulted in a literature that is inconclusive.
Some of the concerns about health risks from living near transmitters is directed toward symptoms such as fatigue, sleep disturbances, and frequent headaches. It may be tempting to address such issues in a cross-sectional study of people living near transmitters, in which subjects are asked to report their symptoms. However, this is a design in which exposure is poorly characterized and reporting bias with respect to symptoms is of concern.
Although the likelihood is low that fields emanating from base stations would create a health hazard because of their weakness, this possibility is nevertheless a concern for many people. To date, no acceptable study on any outcome has been published on this.