The military dumped more than 8,000 tons of chemical weapons, including tens of thousands of chemical-filled bombshells and hundreds of bulk containers of chemicals, into the waters south of O'ahu in 1944 and 1945.

And it's still there.

The Army has confirmed that the dumping occurred. However, it admits it does not know exactly where all the materials were dumped and therefore has not monitored debris fields for leaks.

"There is no danger of chemicals washing up on the island," said Dave Foster, a U.S. Army public affairs officer in Washington. But he said he would require further research to learn more about the dumping before he could respond to detailed questions.

Hawai'i scientists said the location of the materials needs to be pinpointed, and it should be determined whether there is chemical leakage and what impact that might have.

"It's a question that should be addressed. Where are they? Are they leaking? And if they're leaking, what's the risk?" said University of Hawai'i emeritus professor of oceanography Rick Grigg. "We should identify it as a high-priority research objective."

The military has dumped materials off the southern shores of O'ahu, ranging from conventional explosives to old aircraft, ships and vehicles. One underwater scientist said chemical dumping is a particular concern.

"There's just too many unknowns," said Christopher Kelley, program biologist for the Hawai'i Undersea Research Laboratory, an agency of the University of Hawai'i's School of Ocean and Earth Science and Technology. "We need more information. A lot of chemicals down there is not a good thing."

Dumped materials surfaced nearly three decades ago during a dredging project that raised several shiny cylinders from the ocean floor off southern O'ahu. At least one was leaking. James Maragos, then a contracting officer with the Army Corps of Engineers and now a coral reef biologist with the U.S. Fish and Wildlife Service, was in charge of the 1976 project.

"The chemical stuff was pulled up off Honolulu Harbor. They were metal containers 2 to 3 feet long. They brought up seven of them. The men were working barefoot on deck, and two or three of them got badly blistered feet (from the leaking chemicals)," Maragos said.

The Army says it believes the incident involved a liquid-filled 4-inch Stokes mortar round from a 1944 dumping in 1,000 feet of water off Pearl Harbor. Maragos said the dredge was miles from there, in 1,200 feet of water, three miles off Honolulu Harbor — suggesting that the Army's assessment of the dumping location was wrong or that there is more chemical weaponry off Hawai'i than has been reported.

Among the toxic chemicals on the ocean floor off O'ahu is mustard used in World War I battlefields. Commonly called mustard gas, it is a liquid that is driven into the air by explosives.

Portions of at least three fields of chemical-filled bombs, mortars and bulk containers are in waters where anglers fish and anchor, scientists conduct research and cables have been laid.

"A thousand feet is not very deep," Grigg said. "People are bottomfishing for onaga at that depth."

Many divers who use the waters off O'ahu are familiar with the sight of military refuse, including weaponry.

"A site that I dive off Wai'anae, there's some stuff at 200 to 220 feet. It's mostly cases of ammunition, big bomb-looking things, tubes. It's old stuff," said Charles Hunter of Hawai'i Kai, who is a recreational technical diver and uses special equipment to dive much deeper than most scuba divers do. "We're careful not to touch any of it."

At the end of World War II, the military dumped tens of thousands of tons of chemical weapons into the oceans of the world — just as a way to get rid of the dangerous material. It was dumped in bays and deep water, loosely dumped over the side of ships and sometimes dumped while encased inside scuttled ships. Occasionally, sailors came across canisters or weapons that were leaking toxic chemicals and simply dumped them into the water.

Limited details on each of dozens of dumpings are contained in a 2001 report by the Historical Research and Response Team of the U.S. Army Research, Development and Engineering Command. That report surfaced during an investigation whose results were published this week by the Times-Dispatch in Richmond, Va.

It details chemical-weapons dumping in the Mississippi River, in the Gulf of Mexico, in Manila Bay, in the North Sea, on both sides of the Atlantic, in the Mediterranean and across the Pacific. For some sites, the Army has coordinates of the dump sites. But not for O'ahu.

Regarding a two-week dumping program in 1945 of more than 4,000 tons of chemical weapons containing military ordnance and storage containers of four toxic chemicals, the report notes: "The material was loaded at Wai'anae, Hawai'i, to avoid moving the munitions through densely populated areas. The exact location of the sea disposal is unknown."

That dumping included seven tons of 1,000-pound hydrogen cyanide bombs; 461 tons of 1,000-pound cyanogen chloride bombs; 28 tons of 500-pound cyanogen chloride bombs; 800 tons of 114-pound mustard bombs; 510 tons of 4.2-inch mustard mortar shells; 1,817 tons of 1-ton mustard containers; and 300 tons of 1-ton lewisite containers.

In 1944, somewhere off Pearl Harbor, 4,220 tons of hydrogen cyanide was dumped, apparently in various loose containers. The Army's Foster said that material is believed to have been dumped in water 1,000 feet deep off south O'ahu, but he was not certain how far from shore.

Also in 1944, the military moved 16,000 100-pound mustard bombs from upper Kipapa and Ala Moana and dumped them at an unspecified location listed as "about five miles" off O'ahu.

All four of the chemical weapons dumped off O'ahu are considered weapons of mass destruction under the United Nations' Chemical Weapons Convention of 1993. The U.S. has signed the convention, which calls for the destruction of all chemical weapons. The U.S. for many years ran the prototype chemical weapons destruction facility at Johnston Atoll, 750 miles southwest of O'ahu.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.