Type: Physical Evidence
Source: Military Investigation Records
The official radiation readings recorded during the Rendlesham Forest Incident on December 28, 1980, by Lt. Col. Charles Halt and his team using an AN/PDR-27 survey meter showed beta/gamma readings of 0.1 milliroentgens per hour (mR/h) at the landing site depressions, with peak readings of 0.07 mR/h compared to a background level of 0.03–0.04 mR/h.
Official Memo Data: The Department of the Air Force memo released in 1983 cited 0.1 mR/h as the peak reading and 0.07 mR/h at the depressions, while noting 0.05 mR/h on a nearby tree.
Witness Discrepancy: SSgt. Monroe Nevels, who assisted with measurements, later stated he recorded 7 mR/h (70 µSv/h) in 1980, though analysts suggest this may have been due to uncalibrated equipment; corrected calculations place the reading at approximately 2.33 µSv/h.
Skeptic Analysis: Astronomer Ian Ridpath and forester Vince Thurkettle argued the radiation increase was of "little or no significance," with the UK National Radiological Protection Board noting the levels were not alarmingly high.
Modern Surveys: A 2018 radiation survey by The Debate confirmed statistically significant radioactive hotspots at the reported landing sites, measuring up to 0.30 µSv/h against a forest background of 0.09 µSv/h