Okinawa Times led with an article by freelance writer Jon Mitchell about a USMC investigative report on the crash landing of a Futenma-based CH-53E helicopter in Okinawa in 2017 that he obtained through the FOIA. According to the report, 144,000 cpm of strontium, more than 5,000 times the normal level, was detected on a component of the aircraft that burned up after the unscheduled landing. The component where the strontium was found was the In-Flight Blade Inspection System (IBIS), which monitors the condition of the blade. According to the journalist, the Marines at the time acknowledged that the aircraft contained radiation but stressed that the quantity was too small to pose a risk to health.
The investigative report also allegedly referred to the detection of 700 nanograms of toxic PFOS, almost twice the U.S. permissible level, in soil sampled from the impact site. The Marines reportedly disposed of the contaminated soil as toxic waste. Mitchell concluded that the finding points to the U.S. military’s use of foam extinguisher to put out the fire, which the Japanese side denied at the time, adding that the survey of air and soil collected by the Japanese side after the U.S. military retrieved the burned aircraft and soil in the vicinity showed no abnormal levels of radiation or harmful agents.
The paper said in a separate article that the U.S. military apparently chose not to convey to the Japanese side the contamination of the soil, quoting a scientist as saying that it is wrong to claim that the level of radiation detected would not have an adverse effect on human health.