According to the Air Force Times, blood tests of F-22 pilots showed a host of chemicals, including anti-freeze, propane and burned polyalphaolefin, a synthetic oil, after flights where they reported experiencing cognitive problems. These toxins, along with carbon monoxide, may be causing hypoxia, which is a lack of oxygen. Hypoxia can cause reduced brain function and memory loss. F-22 pilots reported being unable to remember how to change radio frequencies and scraping treetops when approaching the runway. In November 2010, an F-22 crashed in Alaska and the pilot, Capt. Jeffrey Haney, was killed. Sources told the Air Force Times that in his final radio calls he sounded drunk, a symptom of hypoxia.
"These guys are getting tested for toxins and they’ve [gotten] toxins out of their bloodstreams. One of the guys was expelling propane."