Ground crew increased risk is probably coming almost completely from exposure to carcinogens in the materials they're working with. However, the gap between gr

Ground crew increased risk is probably coming almost completely from exposure to carcinogens in the materials they're working with. However, the gap between ground crew rates and air crew rates, plus known similar effects in civilian airliner crew (https://www.cdc.gov/niosh/topics/aircrew/cancer.html https://www.cdc.gov/niosh/topics/aircrew/cancer.html) indicates that it's likely that a significant component of increased risk for pilots and aircrew may be related to high altitude. This doesn't rule out something like... increased exposure to flame-retardants (or something) (fabrics, other materials, or maybe off-gasing into air supply) that may be carcinogenic.