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Microwave Radiation and Human Tolerance: A Review

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Jerome B. Westin, M.D. · 1968

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Early 1968 research recognized microwave radiation affects humans through both heating and non-thermal biological mechanisms.

Plain English Summary

Summary written for general audiences

This 1968 study examined human tolerance limits for microwave radiation exposure, investigating both thermal (heating) and non-thermal biological effects. The research focused on understanding safe exposure levels for humans working with radar and other microwave technologies. This represents early scientific recognition that microwave radiation could affect human biology beyond just tissue heating.

Why This Matters

This study represents a pivotal moment in EMF science - 1968 was when researchers first began systematically investigating whether microwave radiation affects humans through mechanisms beyond simple tissue heating. The distinction between thermal and non-thermal effects identified in this research remains central to today's EMF health debates. While radar operators in 1968 faced intense occupational exposures, the microwave frequencies studied here are essentially the same ones now used in WiFi routers, cell towers, and smart devices that surround us daily. The difference is that what once required massive military radar installations to generate, we now carry in our pockets and install throughout our homes, creating chronic low-level exposures that this early research couldn't have anticipated.

Figures from the Original Paper

Diagram extracted from the original research document.

graphPage 5 - Fig. 1: Fat Thickness (K = skin thickness in cm.) After Schwan, Ref. 7.
p. 5 of the original PDF

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 15 MHz to 300 MHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 15 MHz to 300 MHzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study.

Study Details

To examine the biological effects of microwave radiation and determine meaningful and realistic limits for human exposure

Review of existing literature and studies on microwave radiation effects on human tissue, including ...

MWR can cause both thermal and non-thermal biological damage. Thermal effects include simple thermal...

The present 10 mw/cm² limit is inadequate for modern high-powered radar systems. The biological hazard of MWR is extremely complex with numerous variables including frequency, power, exposure duration, tissue properties, and emission characteristics. Systematic investigation is needed to establish meaningful exposure limits. The need for controlled experiments and documentation of exposure conditions is emphasized.

Cite This Study
Jerome B. Westin, M.D. (1968). Microwave Radiation and Human Tolerance: A Review.
Show BibTeX
@article{microwave_radiation_and_human_tolerance_a_review_g5115,
  author = {Jerome B. Westin and M.D.},
  title = {Microwave Radiation and Human Tolerance: A Review},
  year = {1968},
  
  
}
No DOI on file for this study.

Quick Questions About This Study

The specific tolerance levels aren't detailed in available records, but this research established foundational understanding of human microwave exposure limits for both thermal heating effects and non-thermal biological responses in occupational settings.
While 1968 radar systems produced much higher intensity exposures than modern consumer devices, they used similar microwave frequencies. Today's chronic low-level exposures from WiFi and cell phones weren't anticipated by early researchers.
The study recognized that microwave radiation could affect human biology through mechanisms beyond tissue heating, though specific non-thermal effects aren't detailed in available documentation. This distinction remains crucial in modern EMF research.
With radar technology expanding rapidly for military and civilian use, understanding safe human exposure limits became critical for protecting workers and operators from both immediate heating effects and subtler biological impacts.
This early recognition of both thermal and non-thermal effects laid groundwork for exposure guidelines, though current safety standards still primarily focus on preventing tissue heating rather than addressing non-thermal biological mechanisms.