An Analysis Of Radiofrequency And Microwave Absorption Data With Consideration Of Thermal Safety Standards
Richard A. Tell · 1978
This foundational 1978 EPA analysis established thermal-based RF safety standards that remain largely unchanged despite decades of non-thermal research.
Plain English Summary
This 1978 EPA technical report analyzed radiofrequency and microwave absorption data to evaluate thermal safety standards for human exposure. The study examined how RF and microwave energy is absorbed by biological tissue and assessed whether existing safety guidelines adequately protect against heating effects. This represents early government recognition that RF/microwave exposure needed systematic safety evaluation.
Why This Matters
This EPA report from 1978 marks a pivotal moment when federal agencies first began systematically analyzing RF and microwave absorption data for safety purposes. The reality is that this early work focused exclusively on thermal effects - the heating of tissue - which became the foundation for our current safety standards. What this means for you is that today's exposure limits are still based on this nearly 50-year-old thermal-only approach, despite decades of research showing biological effects occur well below heating thresholds.
The science demonstrates that our bodies absorb RF and microwave energy from sources like cell phones, WiFi routers, and smart meters at levels that don't cause heating but may still trigger cellular responses. This 1978 analysis helped establish the specific absorption rate (SAR) concept that regulators still use today, yet it ignored the growing evidence of non-thermal biological effects that we now know occur at much lower exposure levels.
Finding
A method of specifying safety standard limits based on the electromagnetic field energy density rather than the plane wave, free-space equivalent power density is presented. The analysis reveals a particularly important resonance frequency range, 10 MHz < f <1000 MHz, in which RF and MW absorption may lead to whole body thermal loads several times the whole body basal metabolic rate for exposures equal to the present safety standard in use in the United States.
In their words
“A method of specifying safety standard limits based on the electromagnetic field energy density rather than the plane wave, free-space equivalent power density is presented. The analysis reveals a particularly important resonance frequency range, 10 MHz < f <1000 MHz, in which RF and MW absorption may lead to whole body thermal loads several times the whole body basal metabolic rate for exposures equal to the present safety standard in use in the United States.”
Exposure Information
Specific exposure levels were not quantified in this study.
Study Details
To analyze existing radiofrequency and microwave absorption data to examine the frequency dependent phenomenon of biological tissue heating and determine exposure field intensities associated with various levels of RF and MW induced thermal loading.
The analysis examines the absorption of nonionizing radiation as a thermal load on body tissues, usi...
The analysis reveals a particularly important resonance frequency range, 10 MHz < f <1000 MHz, in wh...
The analysis demonstrates that RF and MW absorption in the frequency range of 10 MHz to 1000 MHz can lead to whole body thermal loads several times the whole body basal metabolic rate for exposures equal to the present safety standard in use in the United States. The analysis provides a method of specifying safety standard limits based on electromagnetic field energy density rather than plane wave, free-space equivalent power density.
Show BibTeX
@article{an_analysis_of_radiofrequency_and_microwave_absorption_data_with_consideration_o_g4421,
author = {Richard A. Tell},
title = {An Analysis Of Radiofrequency And Microwave Absorption Data With Consideration Of Thermal Safety Standards},
year = {1978},
}