Value chain · CLM-1340
In plain terms
In an early-1960s US Air Force study, two dogs spent thousands of hours in a microwave beam of 20 milliwatts per square centimetre and showed no clear harm, though both put on less weight than expected. Two animals are far too few to show that the level is safe.
The claim as recorded
A US Air Force technical note (Rome Air Development Center, RADC-TDR-62-694, received by ASTIA in April 1963) reports that two female beagles were exposed to pulsed 24 GHz (1.25 cm) microwaves held at 20 mW/cm2 over about 20 months: one for 2,631 hours (6.7 hours a day, 5 days a week) and one for 3,970 hours (16.5 hours a day, 4 days a week). It reports that the dogs showed no signs of radiation effects; that rectal temperature, blood volume, blood counts, cholesterol and protein-bound iodine showed no significant change; that no eye abnormalities were produced; and that both dogs bred, with litters after 200, 1,500 and 1,850 hours of exposure. Weight gain was subnormal in both: one gained 0.3 kg and the other lost 1.2 kg over the 20 months.
Evidence behind this: T3, a US Air Force technical note with named authors and a stated method; it permits "the report states Y". The work was sponsored by the Air Force.
Scope and limits
Two litter-mate animals and no sham-exposed control in the summary. Only the side facing the antenna was exposed, and with a half-power diameter of about 20 cm the body was not evenly exposed. At 24 GHz energy is deposited near the surface, so the result does not carry over to 2.45 GHz or 5.8 GHz without a scaling argument, which the note does not give. Pulsed radar source; duty cycle partly illegible; 20 W average / 40 kW peak = 0.0005 (our arithmetic), consistent with the visible 0.000[..]. Each of the three litters included still-births (one of five, two of five, one of four); the note calls reproduction normal and gives no control rate. Methods and results pages printed 3-6 were not render read.
What it assumes
The 20 mW/cm2 is the stated incident density at the exposure box; no absorbed dose is given.
Where it comes from
PDF p.2: "This investigation was sponsored by the Rome Air Department Center" (as printed). PDF p.3 / printed 2: "(24,000 megacycles, wavelength 1.25 cm)"; "average power output of 20 watts. Peak power output was 40 kilowatts"; "power density was kept constant at 20 mw/cm2"; half-power diameter "approximately 20 cm". PDF p.8 / printed 7: "the dogs showed no signs of radiation effects"; "No eye abnormalities were produced"; "Both dogs reproduced normally"; "The gain in body weight was subnormal in both animals"; 2631 and 3970 hours; litters after 1500, 200 and 1850 hours. PDF p.9 / printed 8: weight lost net of excreta, 3.5 and 1.8 g per hour of exposure.
Basis: mW/cm2 incident; hours of exposure
Related records
- Answers question
- QST-001 not published in this release
Cite this
energyaperture.com/c/clm-1340
CLM-1340, Energy Aperture, as of 1963-04.