The military will pay the University of Hawai'i $2 million to use sonar and manned and unmanned submersibles to survey chemical weapons dumped about five miles south of Pearl Harbor at the end of World War II.

Officials said the study could begin in late summer of next year, but what was dumped and where the dumping occurred remain questions that could complicate the search.

Tad Davis, deputy assistant secretary of the Army for the environment, safety and occupational health, said the project could establish procedures for determining whether munitions disposed of at sea pose a threat to human or marine health.

Some O'ahu residents, particularly on the Wai'anae Coast, have called for a cleanup in recent years of the munitions that are so rife in areas that one popular dive spot is called "Ordnance Reef."

The U.S. military has said about 2,600 tons of chemical mustard, cyanogens chloride, hydrogen cyanide and lewisite were dumped at two deep-water locations five to ten miles off the Wai'anae Coast and Pearl Harbor between 1944 and 1946.

The Army also has acknowledged that thousands more tons of chemical munitions were dumped at another unknown site off the coast of West O'ahu in fall 1945.

Gary Ostrander, UH-Manoa vice chancellor for research and graduate education, said existing records may not be accurate and more munitions than realized may have been dumped.

Ostrander said researchers will have to put themselves in the shoes of military members in the 1940s who were given the task of disposing of old chemical weapons at sea.

"It's Friday night and you've got a date. Did you go the full 5 miles? Or how accurate were your instruments? Did you actually go 6 miles?" Ostrander said. "And where exactly in the ocean is the 5-mile point? That could be a pretty big sweep."

Ostrander said the $2 million, appropriated in the 2007 defense budget, "is in no way going to allow us to survey everything we need to survey around these islands and figure everything out." That's going to be a longer-term effort.

President Bush on Tuesday signed a 2008 defense appropriation bill that includes $5.5 million more for the study of chemical weapons dumped off O'ahu, and determination of whether the munitions should be removed or left in place. Part of that funding is expected to go to UH for continuing research on the munitions.

Roy Wilkens, with UH's Hawai'i Institute of Geophysics and Planetology and the chief scientist for the survey project, said a remotely operated vehicle and manned submersibles Pisces IV and V would be used to examine munitions in about 1,000 to 2,000 feet of water.

The munitions dump site to be examined is thought to be south of the spot where a Japanese midget submarine from the Dec. 7, 1941 attack on Pearl Harbor was discovered by UH in 2002. The area has been likened to a military junkyard with everything from porcelain cups and toilets to old bombs, vehicles and planes. A Douglas SBD Dauntless dive bomber was found this year.

Reach William Cole at wcole@honoluluadvertiser.com.