Last December, Army Times reported on the rise of symptoms among soldiers in Iraq and Afghanistan who had suffered direct exposure to burn pits:

Leaked Memo: Pentagon Knowingly Exposed U.S. Soldiers To Toxic Waste

The Pentagon allegedly endangered U.S. soldiers by implementing and covering-up dangerously toxic waste-incineration practices at Balad Airbase in Iraq during years past, as revealed in a leaked Air Force memo [PDF]. Raw Story, which first reported the leak, writes this:
The document, written by an environmental engineering flight commander in December of 2006 and posted on Wikileaks on Tuesday, details the risks posed to US troops in Iraq by burning garbage at a US airbase. It enumerates myriad risks posed by the practice and identifies various carcinogens released by incinerating waste in open-air pits.