The agent chloropicrin, used in World War I chemical weapons, was found in unexploded ordnance during the cleanup of a Schofield Barracks firing range for Stryker Brigade use, officials said.

The Army yesterday said six of 14 munitions tested contain the asphyxiator, which causes tearing and throat irritation, and fluid to enter the lungs.

Initial X-rays showed the munitions to be filled with liquid and to have unstable fuses that make them unsafe to move. Demolition experts have recommended destroying them in place.

An additional 138 munitions recovered from the range in recent months are in secured storage at Schofield and will undergo testing using a portable isotopic neutron spectroscopy system that uses gamma rays to identify a chemical signature, the Army said.

"We are working with some of the best experts and most cutting edge technologies in the field," said Col. Howard Killian, commander of U.S. Army Garrison, Hawai'i, in a release. "We will be able to safely dispose of these munitions. The public's health and safety is foremost in our concerns."

A coalition of environmental and Native Hawaiian rights groups last month called for an independent investigation and disclosure by the Army of depleted uranium munitions use in Hawai'i after the material was found at Schofield.

The Army said 15 tail assemblies from spotting rounds made of D-38 uranium alloy, also called depleted uranium, were found by Zapata Engineering while the contractor was clearing the range area of unexploded ordnance and scrap metal.

The tail assemblies are remnants from training rounds associated with an obsolete weapon system that was on O'ahu in the 1960s, and their low-level radioactivity represents no danger, the Army said.

"We've always been concerned about the environmental health impacts of military activity here," said Kyle Kajihiro, program director for the American Friends Service Committee. "If there are more chemical weapons in the Schofield area or in any of the ranges, that would be a serious concern that they be cleaned up to the safest level possible, and that the public be informed about what's going on."

KHON 2 News reported that witnesses to the unexploded ordnance discoveries said the munitions also contain phosgene, which causes lung damage, and the blistering agent mustard.

Kendrick Washington, a Schofield spokesman, said the suspect munitions date to World War I and World War II, but only the chloropicrin has been identified.

"We're looking into the history of the munitions," he said. "I can't even speculate why they're here. Obviously, back then the world was a different place."

Nine teams with Zapata have been working on the 820-acre site since July 2004 to remove unexploded ordnance. The haul has included artillery rounds, grenades and mortars.

The cleanup is necessary for a new Stryker training area. Soldiers will practice dismounted maneuvers, as well as mounted 50-caliber machine gun and MK-19 grenade launcher firing.

The Army said Thursday that it closed three aircraft maintenance hangars at Wheeler Army Airfield because of cadmium and chromium contamination.

The Army still has not determined the location of most of the more than 8,000 tons of chemical munitions dumped off O'ahu at the end of World War II. Congressional members are calling for a survey of dumping sites and research into their long-term threats to public and environmental health and the possibility and cost of cleaning them up.

Reach William Cole at wcole@honoluluadvertiser.com.