Strikingly, however, it does acknowledge that air samples taken in 2007 found particulate matter levels higher than military recommendations in 50 of 60 cases — some two times allowable toxic levels, but others as many as six times.

The flyer given to troops appears to contradict assertions by the Air Force’s own investigators. In the leaked document, titled “Burn Pit Health Hazards,” Air Force Bioenvironmental Engineering Flight Commander Darrin Curtis expressed shock that troops were knowingly exposed to such risks.

“It is amazing that the burn pit has been able to operate without restrictions over the past few years without significant engineering controls being put in place,” Curtis wrote.

“In my professional opinion, there is an acute health hazard for individuals,” he added. In addition to carcinogens, “there is also the possibility of chronic health hazards associated with the smoke.”

Curtis noted that the chemicals associated with burning plastics, rubber and other common trash items included arsenic, benzene, formaldehyde, hydrogen cyanide, sulfuric acid and various other chemicals.

“Just the Facts,” while playing down long-term risks, also identified dioxins among tested samples. Dioxins were also present in Agent Orange, the notorious herbicide used during the Vietnam War. Benzene is known to cause leukemia, and cyanide and arsenic have throughout history been used as poisons to induce death.

Soldiers complain of chronic conditions

An Army Times investigation in 2008 found anecdotal evidence of health conditions caused by exposure to the fires.