WASHINGTON — Titanium and other metals found in dust at a base in Iraq have been linked to the dust found in six sick soldiers' lungs, according to a study set to be released Monday.

"We biopsied several patients and found titanium in every single one of them," said Anthony Szema, an assistant professor at Stony Brook School of Medicine who specializes in pulmonology and allergies. "It matched dust that we have collected from Camp Victory" in Iraq.

The dust is different from dust found elsewhere in that human lungs are unable to dispel it through natural immune-system processes. The Iraq dust comes attached to iron and copper, and it forms polarizable crystals in the lungs, Szema said. The particles — each bit 1/30th the size of a human hair — have sharp edges.

"They've inhaled metal," Szema said. "It's not a little; it's a lot."

All of the veterans came in for help because they were short of breath, said Szema, who also heads the allergy clinic at the Veterans Affairs Medical Center in Northport, N.Y. Dozens have been diagnosed with constrictive bronchiolitis, a narrowing of the lung's smallest passageways that occurs only after exposure to an environmental toxin or in lung-transplant patients.

There are several theories as to why the dust is different, said Szema, who will release his study at the Symposium on Lung Health after Deployment to Iraq and Afghanistan.

It may have been created by burn pits used to eliminate everything from Styrofoam to vehicles to computers to unexploded ordnance in both Iraq and Afghanistan. At Balad Air Base in Iraq, workers burned 240 tons of trash a day in an open pit a mile from servicemembers' sleeping quarters.

It may be naturally occurring.

Or it may have been produced in the 1991 Persian Gulf war when Iraqi missiles and U.S. bombs melded dust to metal, said Antonietta Gatti, a member of the Italian Scientific Committee for Prevention and Control of Diseases in soldiers of the Italian Ministry of Defense. She specializes in studying nanoparticulate matter.

Szema and his team had the lung biopsies analyzed at the Department of Energy's National Laboratories, where they could hit it with "world's brightest light," Szema said. Each sample showed a crystal with dust inside.

In March, his team published a study in the Journal of Occupational and Environmental Medicine after exposing mice to samples of the same dust. The mice developed lung inflammation similar to that seen in humans, including the inability to push the crystals out of their lungs. Their T-cell counts also went down to less than 30 percent of what they'd had before exposure. A T-cell is a white blood cell key to immunity.

"The cells that defend lung cells can not engulf and digest the titanium," Szema said. "It's different from other dust."

Titanium and iron are both associated with pulmonary fibrosis and pulmonary hypertension in humans, Szema said.

Last month, the Defense Department released its annual relative morbidity report. A USA TODAY analysis of reports dating from 2001 to 2013, as well as Defense Manpower Data, shows that the number of people reporting respiratory and chest symptoms increased from a rate of 406 per 10,000 in 2001 to 744 per 10,000 in 2013.

Chronic obstructive pulmonary disease, a disease typically associated with smoking that usually strikes in people older than 40, increased from a rate of 98 per 10,000 in 2001 to 147 in 2013. It hit a high of 218 per 10,000 in 2009.

"All other respiratory disease" increased from a rate of 150 per 10,000 in 2001 to 273 per 10,000 in 2013.

An Armed Forces Health Surveillance Center report from 2012 also showed a 150 per 1,000 rate of clinic visits for respiratory diseases before the wars in Iraq and Afghanistan, and a rate of 173 per 1,000 rate during the war years.

Szema's research has shown that 14 percent of servicemembers who deployed to Iraq or Afghanistan had new-onset respiratory problems, including shortness of breath, coughing, wheezing and chest tightness.

Bob Miller, a pulmonologist at Vanderbilt University Medical Center in Tennessee, diagnosed chronic bronchiolitis in 50 101st Airborne soldiers at Fort Campbell, Ky., after they complained of being short of breath. He had to perform biopsies to make the diagnosis as the disease is hard to spot with an X-ray or other imaging technology.

"This looks pretty similar to Bob's data," Szema said. "It's pretty scary."

