quote: Toxins found in pilots’ blood include oil fumes, residue from burned polyalphaolefin (PAO) anti-freeze, and, in one case, propane. Carbon monoxide, which leaves the blood quickly, is also suspected.“There is a lot of nasty stuff getting pumped into the pilots’ bloodstream through what they’re breathing from that OBOGS [On-Board Oxygen Generation System]. That’s fact,” one former F-22 pilot said. “How bad it is, what type it is, exactly how much of it, how long — all these things have not been answered.”The blood tests were performed after each of the 14 incidents in which pilots reported various cognitive dysfunctions and other symptoms of hypoxia. One couldn’t remember how to change radio frequencies. Another scraped trees on his final approach to the runway — and later could not recall the incident.