The University of Hawaii's two submersibles will spend 15 days beginning Monday filming and taking water and sediment samples south of Pearl Harbor as part of an Army project to determine the risks of nearly 600 tons of chemical weapons dumped there in 1944.

Tad Davis, the Army's deputy assistant secretary for the environment, safety and occupational health, said yesterday 10 dives will be made by the Hawaii Undersea Research Laboratory submersibles Pisces IV and V at an area dubbed “;Hawaii-05”; by the Army.

The two submersibles will make the dives in the area where the depth ranges from 900 to 2,000 feet during the day. The work is to continue at night using remotely operated underwater vehicles.

In the past, the Army has said 16,000 M47-A2 bombs containing 598 tons of mustard gas were dumped in the area about Oct. 1, 1944. Each chemical bomb weighs 100 pounds and is nearly 32 inches long. The practice of ocean dumping was banned in 1972.

Between 1932 and 1944, chemical weapons, such as blister agents lewisite and mustard gas and blood agents hydrogen cyanide and cyanogen chloride, were discarded in waters off Oahu. The largest dump is reported to be in area 10 miles west of the Waianae Coast.

Davis has described the job as “;the most comprehensible effort to date to address this issue.”;

He said the dives by the submersibles are part of the Army's effort to determine the characteristics of the site.

“;We are getting to a critical point in that effort,”; Davis said.

All these facts will determine “;what risks are associated with those materials remaining where they are.”;

Davis also is involved in another long-term project on the Waianae Coast where the military already has spent $2.2 million to determine the long-term effects of the dumping of 2,000 World War II-era conventional weapons on the sediment, shellfish, limu and fish near Ordnance Reef. The term “;conventional”; refers to munitions that are not nuclear, biological or chemical.

  The goal there is to clear the water from the shoreline to 120 feet away.

Davis said University of Hawaii and National Oceanic and Atmospheric Administration scientists will conduct two more studies of the water and the tides.

All the studies will eventually lead to an attempt to remove or destroy in place up to 1,500 conventional munitions near Pokai Bay, using remote underwater drones and other robotic techniques perfected by oil companies. The weapons range from .50-caliber or smaller ammunition to 50- to 100-pound bombs and 105 mm projectiles.

The Pentagon began work on the Pokai Bay Ordnance Reef problem in May 2006.

“;I would like to move faster,”; Davis said, “;and I think we are moving at a deliberate pace. I would still like to move this process faster.”;

Davis was to address the International Dialogue on Underwater Munitions Conference today at the Pacific Beach Hotel. He will meet with federal, state and community officials on the Pentagon's action involving Ordnance Reef, chemical munitions, depleted uranium and flammable items known as propellant grains discovered off Maili Beach in Waianae.