Updated

The mysterious deaths of two infants at the same home within three months of each other has prompted a probe into eight other unexplained infant deaths at the Fort Bragg Army base since January 2007, the military said Tuesday.

At a news conference at the base, military leaders say they don't suspect foul play in any of the deaths, and are conducting tests of the air, building materials and other elements at the on-base housing where the deaths occurred.

So far, though, investigators have not found any link between the deaths since the probe was ordered earlier this summer, according to Christopher Grey, spokesman for the U.S. Army Criminal Investigation Command.

"There are no commonalities that we've found thus far," he said.

The vast base, adjacent to Fayetteville, N.C., is home to the U.S. Army Airborne and Special Forces. About 45,000 people live on the base, including about 6,200 families, according to Col. Stephen Sicinski, the garrison commander.

The probe began after investigators noted the deaths of two infants from different families in 2009 at the same address. The first child died in April of last year. Another family moved into the home after the death, and their infant died in July.

A third infant who lived at that address died in 2007, but the death is believed to have occurred at a baby-sitting service off the base.

Neither the identities of the children nor the addresses where they died were disclosed by the Army. Grey said that information will remain confidential during the investigation.

The house where the two deaths occurred is vacant, and will remain unoccupied until the causes are determined, according to Brig. Gen. Michael Garrett, chief of staff of the 18th Airborne Corps.

"We cannot explain two deaths of children at one address, and that's really the problem we're trying to solve," Garrett said.

That anomaly, though, prompted officials at the base to order a review of unexplained infant deaths since January 2007. The 10 deaths being examined are among infants ranging in age from two weeks to eight months. One was attributed to Sudden Infant Death Syndrome, seven were ruled "undetermined" by medical examiners with the Armed Forces Institute of Pathology and two remain under investigation.

All of the deaths may ultimately be attributable to SIDS, a rare but well-established diagnosis in cases where children younger than a year old die without any apparent cause. But that determination can only be made after an autopsy, examination of the death scene and thorough review of the child's medical history.

Even something as common as a persistent cold can be enough to cause medical examiners to rule a death "unexplained" rather than attribute it to SIDS, said Col. Jeffrey Kingsbury, a physician and chief of preventive medicine at Womack Army Medical Center, located on the base.

"If you find anything, a runny nose, then you can't call it SIDS," he said.

Part of the investigation aims to determine whether 10 deaths in just under four years is itself an alarming departure from the norm. That's complicated by the fact that it's hard to establish how many infants are living on the base at any one time.

There are about 3,000 babies born every year at Womack, Sicinski said, which makes it the busiest maternity hospital in the U.S. military. But an unknown number of babies are born elsewhere and move to Bragg with their families.

Nationally, the rate is about .5 SIDS deaths per 1,000 live births, according to the American SIDS Institute.

Investigators, meanwhile, are looking to determine whether environmental factors could have played a role in the infants' deaths. Grey said the investigation has considered everything from the presence of Chinese drywall in the homes to black mold, but has found evidence of neither.