SCHOFIELD BARRACKS, Hawaii -- The U.S. Army said on Tuesday it found no significant public health threat from depleted uranium used decades ago at firing ranges on Schofield Barracks.

Exposure to high levels of depleted uranium can be toxic to a person's nervous system and major organs.

DU is used in weapons during combat, but is no longer used in training.

The Army used weapons containing depleted uranium in Hawaii in the 1960s. Last fall, the Army took more than 1,400 soil, water and air samples at Schofield.

"It's the Army's belief the DU levels are safe the way they are right now," Col. Howard Killian said.

The level for acceptable risk set by the Environmental Protection Agency and the Nuclear Regulatory Commission is 1 in 10,000. The maximum found at Schofield was 3 in 100,000, Army officials said.

"It's well below the EPA and NRC levels. So, we are saying that it is safe," said Howard Takata of the state Department of Health.

The panel of experts that weighed in on the independent study concurred. The small amount of DU was found in large fragments, which made it unlikely that the contaminant could be airborne in dust, according to panel members.

"This is after 40 years plus. This stuff being there, and this stuff does not migrate easily. It's a heavy metal and studies show there is a minimal amount," U.S. Army Safety Officer Greg Komp said.

The Army said records show some 714 rounds containing the radioactive waste were sent to Hawaii. Only about 30 were found at Schofield Barracks firing range.

No one is sure what happened to the rest since the Davy Crockett Weapons System was classified at the time and much of the digging has been through records all across the country.

The fact that the Army has spent more than $2 million to address the environmental and health concerns of the community and its soldiers is unprecedented.

"The Army is spending an enormous amount of resources to go back and clean up this stuff. What people don't realize is normally we don't go back in our impact area and clean up," Killian said.

"The world is a much smaller place nowadays and we can't afford not to address this now," Takata said.

The Army is also looking at the threat from depleted uranium at Pohakuloa Training Center on the Big Island and at Makua Valley on Oahu.