Preliminary measurements of electromagnetic radiation fields near microwave ovens
Solem DL, Remark DG, Moore RL, Crawford RE, Rechen HJL · 1969
1969 testing found microwave ovens leaked over 700 mW/cm² when doors opened, with easily defeated safety systems.
Plain English Summary
This 1969 study tested microwave ovens from five manufacturers to measure radiation leakage when safety systems failed. Researchers found extremely high power densities of over 700 mW/cm² at 30 cm from open-door ovens, and discovered that most safety interlocks could be easily defeated. The findings revealed significant radiation exposure risks from malfunctioning microwave ovens.
Why This Matters
This early research reveals a sobering reality about microwave oven safety that remains relevant today. The power densities measured - over 700 mW/cm² near an open oven - are extraordinarily high, thousands of times greater than typical cell phone exposures. What's particularly concerning is how easily the safety systems could be bypassed, with one oven allowing manipulation without any tools. The study also highlighted measurement inconsistencies between different radiation detection instruments, showing variations up to 12-fold. This demonstrates the challenges in accurately assessing EMF exposures, a problem that persists in modern EMF research. While today's ovens have improved safety standards, this foundational work underscores why proper shielding and functioning door seals remain critical for protecting users from intense microwave radiation.
Finding
Power densities of greater than 700mW/cm² were found 30cm in front of an oven with the door open, and power densities of 10mW/cm² at 120cm from the ovens. Safety interlock switches were examined to find how they operated and how they could be defeated. In all cases except one, operation of safety interlocks relied solely on spring powered switches to prevent the generation of microwaves when the doors were opened. In one case, a safety interlock used the operation of the door latch to inactivate the microwave generation system. In another it was possible to manipulate the interlock system without tools to permit generation of microwave power with the door open.
In their words
“Power densities of greater than 700mW/cm² were found 30cm in front of an oven with the door open, and power densities of 10mW/cm² at 120cm from the ovens. Safety interlock switches were examined to find how they operated and how they could be defeated. In all cases except one, operation of safety interlocks relied solely on spring powered switches to prevent the generation of microwaves when the doors were opened. In one case, a safety interlock used the operation of the door latch to inactivate the microwave generation system. In another it was possible to manipulate the interlock system without tools to permit generation of microwave power with the door open.”
Figures from the Original Paper
Diagrams extracted from the original research document.
Exposure Information
Specific exposure levels were not quantified in this study.
Show BibTeX
@article{preliminary_measurements_of_electromagnetic_radiation_fields_near_microwave_oven_g6432,
author = {Solem DL and Remark DG and Moore RL and Crawford RE and Rechen HJL},
title = {Preliminary measurements of electromagnetic radiation fields near microwave ovens},
year = {1969},
}