New state testing has found that radiation levels in the air near Pohakuloa Training Area on the Big Island are "normal," despite residents' concerns about the possible presence of depleted uranium from military munitions.

Concern that depleted uranium from a 1960s weapon system might be getting kicked up and spread on the wind led to the testing. The Army this summer plans to conduct its own radiological testing at Pohakuloa, Schofield Barracks and Makua Military Reservation.

"The levels were all between three and eight microroentgens per hour — that means it's normal," said Russell Takata, program manager for the state Health Department's Noise, Radiation and Indoor Air Quality Branch.

Takata said the readings include cosmic and geologic radiation normally found in nature.

But Dr. Lorrin Pang, the state Health Department's district officer for Maui County, said testing the air alone is not enough. If the air is measured, "a lot of times it (radiation) is not there ... you won't get anything, so the most consistent thing is to measure soil samples," Pang said.

A plume of dust carrying elevated radiation levels may be present during military training — when dust is kicked up — but not at other times, said Pang, who spent 24 years in the Army and was a preventive medicine officer at Tripler Army Medical Center in the late 1980s.

Pang, who had lent his support to a failed state bill that would have required regular soil testing at Schofield Barracks for radioactive material, has spoken out on the issue as a private citizen and not in his official capacity.

According to the Health Physics Society, the average person in the United States gets about 365 milliroentgens a year from natural and medical X-ray exposure, including exposure to natural radon gas in the air. One thousand microroentgens equals one milliroentgen.

SCHOFIELD, TOO

In January 2006, the Army confirmed it had found 15 tailfin assemblies that contained depleted uranium at a Schofield range. The heavy metal was used in aiming rounds that simulated the trajectory of the Davy Crockett, a recoilless rifle that could fire a 76-pound nuclear bomb.

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

Takata said the state testing was done at five or six sites on May 16 from Kealakekua to Waiki'i on the Big Island. The testing was not done on the 133,000-acre Pohakuloa Training Area itself, but downwind from the base.

"We're looking at the populated areas (for testing), obviously, because if people are living in an area, working in an area, that's where we should be looking," Takata said.

Takata said his staff will conduct periodic testing outside Pohakuloa and is setting up testing in Wai'anae.

"Everyone's talking about Makua and Schofield, so I might as well get those readings, too (in Wai'anae)," Takata said.

RISKY IF INHALED

Pang said the real danger with depleted uranium comes with the vaporized or aerosolized form, which occurs on impact.

"Once it's vaporized and breathed in, the alpha-particle emitters are the most dangerous form of radiation of all, because it's up in close and it sticks to the cells of your lung," he said.

The World Health Organization said inhaled uranium particles may lead to irradiation damage of the lung. Measurements at sites where depleted uranium munitions were used indicate only localized contamination within a few yards of the impact site, the organization said.

OTHER USES

A radiation dose from depleted uranium would be about 60 percent of that from purified natural uranium. Civilian uses for depleted uranium include counterweights in aircraft and shielding in medical radiation. Depleted uranium is used in armor-penetrating military ordinance because of its high density.

"From the amount that the Army disclosed (that it used in Hawai'i), it looks like a small amount," Takata said. "Even at (Pohakuloa), they are saying it's a small amount. Until they (the military) actually do the assessment, we won't know."

Some residents have called for independent testing.

Reach William Cole at wcole@honoluluadvertiser.com.