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Note: This study found no significant biological effects under its experimental conditions. We include all studies for scientific completeness.

Cancer & Tumors

Chronic, low-level (1.0 W/kg) exposure of mice prone to mammary cancer to 2450 MHz microwaves.

No Effects Found

Frei, MR, Jauchem, JR, Dusch, SJ, Merritt ,JH, Berger, RE, Stedham, MA, · 1998

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Long-term microwave exposure at 1.0 W/kg showed no increase in breast cancer rates in cancer-prone mice.

Plain English Summary

Summary written for general audiences

Researchers exposed 100 mice genetically prone to breast cancer to microwave radiation at 2450 MHz (the same frequency used in microwave ovens and early WiFi) for 78 weeks, 20 hours per day. They found no difference in cancer rates between exposed mice (38%) and unexposed mice (30%), and no difference in how quickly tumors developed or grew. This suggests that chronic exposure to this specific level of microwave radiation did not increase breast cancer risk in these cancer-prone animals.

Why This Matters

This study represents important long-term cancer research using exposure levels that exceed what most people experience from wireless devices today. The 1.0 W/kg SAR used here is higher than current cell phone limits (2.0 W/kg maximum, but typically much lower in actual use) and the 20-hour daily exposure far exceeds typical human patterns. While the researchers found no cancer-promoting effects, this study has limitations worth noting. The mice were a specific inbred strain already predisposed to mammary tumors, which may not reflect how radiation affects normal tissue. Additionally, this 1998 study predates our current understanding of how pulsed digital signals differ from the continuous wave radiation used here. The science demonstrates that not all EMF studies show harmful effects, but individual studies like this one don't settle the broader question of wireless safety. What this means for you is that the research landscape includes both concerning findings and reassuring ones like this study, which is why many scientists call for more research rather than definitive safety conclusions.

Exposure Details

SAR
1 W/kg
Source/Device
2450 MHz
Exposure Duration
78 weeks (20 h/day, 7 days/week)

Exposure Context

This study used 1 W/kg for SAR (device absorption):

Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 1 W/kgExtreme Concern - 0.1 W/kgFCC Limit - 1.6 W/kgEffects observed in the Extreme Concern range (Building Biology)FCC limit is 2 times higher than this level
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 2.45 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 2.45 GHzPower lines50/60 Hz5G mm28 GHzLogarithmic scale

Study Details

The aim of this study is to investigate Chronic, low-level (1.0 W/kg) exposure of mice prone to mammary cancer to 2450 MHz microwaves

In the current study, the specific absorption rate (SAR) was increased from 0.3 W/kg to 1.0 W/kg. Th...

There was no significant difference between exposed and sham-exposed groups with respect to the inci...

Thus long-term exposures of mice prone to mammary tumors to 2450 MHz RF radiation at SARs of 0.3 and 1.0 W/kg had no significant effects when compared to sham-irradiated animals.

Cite This Study
Frei, MR, Jauchem, JR, Dusch, SJ, Merritt ,JH, Berger, RE, Stedham, MA, (1998). Chronic, low-level (1.0 W/kg) exposure of mice prone to mammary cancer to 2450 MHz microwaves. Radiat Res 150(5):568-576, 1998.
Show BibTeX
@article{frei_1998_chronic_lowlevel_10_wkg_3026,
  author = {Frei and MR and Jauchem and JR and Dusch and SJ and Merritt  andJH and Berger and RE and Stedham and MA and},
  title = {Chronic, low-level (1.0 W/kg) exposure of mice prone to mammary cancer to 2450 MHz microwaves.},
  year = {1998},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/9806599/},
}
PubMed: 9806599

Cited By (51 papers)

View all 51 citing papers on Semantic Scholar

Quick Questions About This Study

A 1998 study found no increased breast cancer risk from microwave radiation at 2450 MHz. Researchers exposed cancer-prone mice to this frequency for 78 weeks and found identical cancer rates (38% vs 30%) between exposed and unexposed groups, suggesting no significant cancer risk.
Research on 2450 MHz radiation (early WiFi frequency) showed no cancer effects in a long-term animal study. Mice exposed for 78 weeks developed tumors at the same rate as unexposed mice, with no difference in tumor growth or development timing.
A comprehensive 78-week study found no health effects from 2450 MHz radiation exposure in cancer-prone mice. The research showed no increased tumor rates, faster cancer development, or changes in tumor growth patterns compared to unexposed animals.
Studies suggest minimal breast cancer risk from microwave oven frequencies. Research on 2450 MHz radiation (microwave oven frequency) found no increased cancer rates in susceptible animals, even with chronic 20-hour daily exposure over 78 weeks.
Long-term microwave exposure at 2450 MHz did not impact tumor development in research studies. Cancer-prone mice showed identical tumor onset timing, growth rates, and cancer types whether exposed to microwaves or not over 78 weeks.