Army Staff Sgt. Mark Jackson kept a daily journal, documenting how he became permanently sickened while stationed at the Karshi-Khanabad Air Base in Uzbekistan in 2003.
Yellow tabs protrude from his blue spiraled notebook, marking dozens of pages in which he logged his growing list of health issues.
“The air here is poison,” he wrote on July 28, 2003, shortly after arriving at the Soviet-era air base, according to journal entries he shared with NBC News.
The symptoms emerged one by one throughout the pages: stomach cramps, incessant headaches and extreme exhaustion. By the time Jackson made it back to Melbourne, Florida, in April 2004, the former marathoner said he could barely walk up a flight of stairs.