3,138 Studies Reviewed. 77.4% Found Biological Effects. The Evidence is Clear.

Long-term, low-level microwave irradiation of rats.

Bioeffects Seen

Chou CK, Guy AW, Kunz LL, Johnson RB, Crowley JJ, Krupp JH · 1992

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Lifetime microwave exposure at levels below current safety limits produced measurable biological effects in laboratory animals.

Plain English Summary

Summary written for general audiences

Researchers exposed 200 rats to low-level microwave radiation (similar to cell phone frequencies) for nearly their entire lifetimes, 21.5 hours daily for 25 months. The study monitored blood chemistry, hormone levels, immune function, and overall health throughout the animals' lives. This represents one of the most comprehensive long-term studies of microwave radiation effects on living organisms.

Why This Matters

This landmark study stands out for its exceptional duration and scope - exposing animals to microwave radiation for essentially their entire adult lives at power levels comparable to what we might experience from wireless devices. The researchers used 2,450 MHz radiation, the same frequency used in microwave ovens and early WiFi systems, at SAR levels of 0.15-0.4 W/kg. For context, current cell phone SAR limits are 1.6 W/kg in the US, making these exposure levels relatively modest by today's standards. What makes this research particularly significant is its lifetime exposure protocol and comprehensive health monitoring - exactly the kind of long-term data that's been largely missing from EMF safety discussions. The science demonstrates that even low-level, chronic exposures can produce measurable biological changes, challenging the assumption that brief safety studies are sufficient to assess real-world health risks.

Exposure Details

SAR
0.15, 0.4 W/kg
Source/Device
2,450-MHz
Exposure Duration
Began at 8 weeks of age and continued daily, 21.5 h/day, for 25 months

Where This Falls on the Concern Scale

Study Exposure Level in ContextA logarithmic scale showing exposure levels relative to Building Biology concern thresholds and regulatory limits.Study Exposure Level in ContextThis study: 0.15, 0.4 W/kgExtreme Concern0.1 W/kgFCC Limit1.6 W/kgEffects observed in the Extreme Concern range (Building Biology)FCC limit is 11x higher than this exposure level

Study Details

Our goal was to investigate effects of long-term exposure to pulsed microwave radiation. The major emphasis was to expose a large sample of experimental animals throughout their lifetimes and to monitor them for effects on general health and longevity.

An exposure facility was developed that enabled 200 rats to be maintained under specific-pathogen-fr...

After 13 months, 10 rats from each group were euthanatized to test for immunological competence and ...

Cite This Study
Chou CK, Guy AW, Kunz LL, Johnson RB, Crowley JJ, Krupp JH (1992). Long-term, low-level microwave irradiation of rats. Bioelectromagnetics 13(6):469-496, 1992.
Show BibTeX
@article{ck_1992_longterm_lowlevel_microwave_irradiation_905,
  author = {Chou CK and Guy AW and Kunz LL and Johnson RB and Crowley JJ and Krupp JH},
  title = {Long-term, low-level microwave irradiation of rats.},
  year = {1992},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/1482413/},
}

Quick Questions About This Study

Researchers exposed 200 rats to low-level microwave radiation (similar to cell phone frequencies) for nearly their entire lifetimes, 21.5 hours daily for 25 months. The study monitored blood chemistry, hormone levels, immune function, and overall health throughout the animals' lives. This represents one of the most comprehensive long-term studies of microwave radiation effects on living organisms.