WHAT BIOLOGICAL EFFECTS CAN BE CAUSED BY RF ENERGY?

Biological effects can result from 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 excess 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, if they exist, have been referred to as “non-thermal” effects.   A number of reports have appeared in the scientific literature describing the observation of a range of biological effects resulting from exposure to low levels of RF energy.   However, in most cases, further experimental research has been unable to reproduce these effects.   Furthermore, since much of the research is not done on whole bodies (in vivo), 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.