U.S. Navy Capt. Mark Lyles, chairman of medical sciences and biotechnology at the Center for Naval Warfare Studies at the Naval War College in Newport, R.I., and colleagues found dust particles collected in Iraq and Kuwait contain 37 metals, including aluminum, lead, manganese, strontium and tin -- heavy metals linked to neurological disorders, cancer, respiratory ailments, depression and heart disease, USA Today reported.
The dust contains 147 different kinds of bacteria, as well as fungi, the scientists say.
"From my research and that of others, I really think this may be the smoking gun," Lyles told USA Today. "It fits everything -- symptoms, timing, everything."
The scientists said the particles are smaller and easier to inhale than most dust particles and some may breathe the dust deeply into their lungs.
A USA Today analysis of military morbidity records from 2001 to 2010 found since the war in Afghanistan began in 2001 and the Iraq war began in 2003, the military has experienced a 251 percent increase in the rate of neurological disorders per 10,000 active-duty service members -- a 47 percent increase in the rate of respiratory issues and a 34 percent increase in the rate of cardiovascular disease.
Department of Defense officials say the military has examined the concerns raised by the studies of Lyles, and found the dust is "not noticeably different from samples collected in the Sahara Desert and desert regions in the U.S. and China."
Richard Meehan of the National Jewish Health in Denver, who assisted the U.S. Army's Public Health Command with a particulate matter study says more research is needed.
"I don't want a false cause," he told USA Today. "You miss really discovering what else is out there."