Friday, June 3, 2016

National Toxicology Program: Not the First Government Study to Find Wireless Radiation Can Cause Cancer in Lab Rats

The National Toxicology Program's (NTP) recent study is not the first randomized controlled trial to find that exposure to non-thermal levels of microwave radiation can cause cancer in male rats.

A U.S. Air Force study conducted from 1980 to 1982 which was documented in a series of nine technical reports and later published in the peer-reviewed journal, Bioelectromagnetics, found that 18% of 100 male rats exposed to low-intensity microwave radiation for two years developed cancer as compared to only 5% of 100 rats in the sham-exposed control group. The relative risk of developing cancer in the wireless radiation exposure group was 4.46 (p = .005).

"A statistically significant increase of primary malignancies in exposed rats vs. incidence in controls is a provocative finding, but the biological significance of this effect in the absence of truncated longevity is conjectural. The positive findings need independent experimental evaluation." (Chou et al., 1992).

The objective of this 5-year, $5 million study was to create a "generalized level of radiation that would provide whole-body exposure based on the maximum of permissible absorption [ANSI C95.1- 1982, 1983; IEEE C95.1-1991,1992] at the resonant frequency in human beings (0.4 W/kg), as scaled to the proportions of the experimental animal of choice." The microwaves were pulsed and square-wave modulated because prior research had found that extremely low frequency modulation of microwave radiation altered the movement of calcium ions in chicken and cat brains (Adey, 1981).

Differences between 1992 Chou study and 2016 NTP study

The Chou study exposed experimental animals to 2450 MHz "so each rat would have approximately the same size-to-wavelength ratio as a human being exposed at 450 MHz of microwave radiation;" whereas the NTP study exposed rats to 900 MHz microwave radiation that simulated second-generation (2G) cell phone radiation. The rats' average exposure in the Chou study was about 4-10 times lower than in the NTP study (0.15 W/kg to 0.4 W/kg versus 1.5 W/kg to 6.0 W/kg). 

Chou and his colleagues were trying to simulate the effects of radar on people. The frequency tested is close to one of the frequencies currently in use for Wi-Fi, 2400 MHz.

Although the NTP study found increased malignant tumor risk in different organs than the Air Force study, the differences are likely attributable to the different forms of microwave radiation tested.  

Three decades have passed since this Air Force study of wireless radiation was conducted. The FDA called for the NTP to study the effects of radiation from wireless devices 17 years ago. Now the results from the $25 million NTP study suggest that cellphone radiation can also cause cancer in laboratory rats.

When will the federal government fund the research needed to determine the types and amounts of exposure to cellphone and other wireless radiation that are safe? 


Chou CK, Guy AW, Kunz LL, Johnson RB, Crowley JJ, Krupp JH. Long-term, low-level microwave irradiation of rats. Bioelectromagnetics. 1992;13(6):469-96.


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-free (SPF) conditions while housed individually in circularly-polarized waveguides. The exposure facility consisted of two rooms, each containing 50 active waveguides and 50 waveguides for sham (control) exposures. The experimental rats were exposed to 2,450-MHz pulsed microwaves at 800 pps with a 10-microseconds pulse width. The pulsed microwaves were square-wave modulated at 8-Hz. Whole body calorimetry, thermographic analysis, and power-meter analysis indicated that microwaves delivered at 0.144 W to each exposure waveguide resulted in an average specific absorption rate (SAR) that ranged from 0.4 W/kg for a 200-g rat to 0.15 W/kg for an 800-g rat. Two hundred male, Sprague-Dawley rats were assigned in equal numbers to radiation-exposure and sham-exposure conditions. Exposure began at 8 weeks of age and continued daily, 21.5 h/day, for 25 months. Animals were bled at regular intervals and blood samples were analyzed for serum chemistries, hematological values, protein electrophoretic patterns, thyroxine, and plasma corticosterone levels. In addition to daily measures of body mass, food and water consumption by all animals, O2 consumption and CO2 production were periodically measured in a sub-sample (N = 18) of each group. Activity was assessed in an open-field apparatus at regular intervals throughout the study.

After 13 months, 10 rats from each group were euthanatized to test for immunological competence and to permit whole-body analysis, as well as gross and histopathological examinations. At the end of 25 months, the survivors (11 sham-exposed and 12 radiation-exposed rats) were euthanatized for similar analyses. The other 157 animals were examined histopathologically when they died spontaneously or were terminated in extremis.

Statistical analyses by parametric and non-parametric tests of 155 parameters were negative overall for effects on general health, longevity, cause of death, or lesions associated with aging and benign neoplasia. Positive findings of effects on corticosterone level and immune system at 13 months exposure were not confirmed in a follow-up study of 20 exposed and 20 control rats. Differences in 0, consumption and C0,production were found in young rats. A statistically significant increase of primary malignancies in exposed rats vs. incidence in controls is a provocative finding, but the biological significance of this effect in the absence of truncated longevity is conjectural. The positive findings need independent experimental evaluation. Overall, the results indicate that there were no definitive biological effects in rats chronically exposed to RF radiation at 2,450 MHz.

The paper can be downloaded from the FCC website at: