The Army yesterday confirmed that depleted uranium from a 1960s weapons system has been found at Pohakuloa Training Area on the Big Island.

How much of the material was detected remained unclear. The Army said initial testing was done to determine the presence of depleted uranium, or DU, not the quantity of it. There is no public access to the area where the heavy metal was found.

In January 2006, the Army confirmed it had found 15 projectile tailfin assemblies that contained depleted uranium at a Schofield Barracks munitions impact range.

The depleted uranium was used in XM-101 aiming rounds that simulated the trajectory of the Davy Crockett, a formerly classified recoilless rifle that could fire a 76-pound nuclear bomb.

The Army yesterday said the DU at Pohakuloa Training Area is the same type of material found at Schofield.

Earlier this summer, the Army said it had found more depleted uranium fragments at Schofield, and that the aiming rounds also may have been fired at Makua Valley and Pohakuloa.

Contractor Cabrera Services conducted an aerial survey of the impact area at Pohakuloa from Thursday to Saturday as part of the Army's efforts to determine the extent of DU use in Hawai'i.

The Army previously said it was unaware of the presence of the weakly radioactive element until a contractor removing unexploded ordnance for the Stryker brigade discovered it in 2005 at Schofield.

Concern by some Big Island residents that depleted uranium might be getting kicked up, spread on the wind and possibly inhaled led to the testing.

An aerial survey of the impact area at Makua Military Reservation was conducted Aug. 13-14. The Army said the survey was inconclusive because the ground could not be seen because of heavy vegetation.

Depleted uranium was used for spotting, or aiming, rounds for the Davy Crockett because its density mimicked the trajectory of the 76-pound warhead.

A gray cylinder 3 to 6 feet long that was fired would fall away, while the DU aiming round would continue to travel farther, the Army said. The presence of the cylinders is being used as a predictor of DU.

The Army said soil samples were taken at Makua and Pohakuloa, and those samples are being sent to an independent lab for testing.

"Now that DU has been confirmed at Pohakuloa, the Army will coordinate with the state of Hawai'i and the Nuclear Regulatory Commission to determine the next steps," the service said.

State testing in May found normal radiation levels in the air near Pohakuloa Training Area.

The Army earlier this month said it was monitoring air quality during a controlled burn at a Schofield Barracks target range in response to concerns that the fires could put fine particles of depleted uranium in the air.

The controlled burn on 1,100 acres of munitions impact area was done to minimize the chance of brushfires and to prepare the area for testing for the presence of DU.

Lab results from air samples of Schofield's controlled burn July 30 to Aug. 2 showed no DU health hazard from the accompanying smoke, the Army said.

Reach William Cole at wcole@honoluluadvertiser.com.