I wonder if the radiation is radio frequency, that the emissions are controlled. There are two powerful radars on Kwaj. Overflight of the Millstone Hill radar in Westford Massachusetts is prohibited, not because of radiation burns, but the radar is so powerful that it can damage electronics on aircraft. The PAVE PAWS radar at Warner-Robins in Georgia (since moved to Clear, Alaska) routinely illuminated aircraft taking off and landing with fields that exceed safe Electro-Explosive Ordinance limits, until someone realized it was happening. EEO are used in ejection seats. They operated for a while by briefly shutting down the radar when there was a chance an aircraft would fly too close to the near-field beam.
EMCon testing?
What I was able to find was that it is related to a very high power microwave uplink beam that is associated with a recently completed anti ICBM system. It went live about two weeks ago.
If you were to fly over it, I guess you would be treated like a hot dog in a microwave oven.
Interesting.
When I was at Kwaj doing some interference testing on their C-Band PAR and the THAAD prototype that end of the island was pretty well controlled traffic-wise. That C-band PAR was essentially the prototype design for the later SBX seaborne radar.