A federal research ship will get as close as 600 feet — or the length of about two football fields — from Oahu's Leeward Coast as it looks for World War II-era military weapons dumped off Waianae decades ago, the project's chief scientist said Tuesday.

The Pentagon asked the National Oceanic and Atmospheric Administration to assess the danger posed by the weapons in an area known as Ordnance Reef after Waianae residents and members of Hawaii's congressional delegation voiced their concerns.

Worries about the dumped weapons have grown in the islands after The Daily Press in Newport News, Va., reported last year the military had disposed chemical munitions in at least 26 locations off the coasts of 11 states — including Hawaii — over several decades.

Michael Overfield, marine archaeologist and chief scientist for the survey mission, said U.S. military records indicated the Ordnance Reef weapons were conventional, not chemical. But he said researchers would reserve judgment until they finished their survey.

"We're saying: 'We don't know anything. So let's get the best technology to tell us everything that is out there,"' Overfield said. "Let's get the real story. That's why we have this team of experts out here."

The military has identified two locations off Hawaii where it deposited 2,600 tons of mustard, cyanogen chloride, hydrogen cyanide and lewisite between 1944 and 1946. These sites are both much farther from the coast, and at greater depths than Ordnance Reef.

The military will decide what to do about the Ordnance Reef weapons after NOAA finishes its survey report this fall. A 2002 study by the Army Corps of Engineers and Navy divers mapped over 2,000 military munitions in the area.

The NOAA ship Manacat will first use sonar to look for anomalies on the seabed at depths ranging from 18 feet to 300 feet.

A robot and divers will take sediment, water, and fish samples to help researchers analyze the impact the weapons have had on the environment.

The robot, a remote controlled submersible vehicle about the size of a medium-sized dog, will take visual images of the weapons.

William Aila, Waianae harbormaster, said he's seen hundreds of grenades, four-or-five-inch long shells and ammunition pallets while scuba diving in Ordnance Reef for fish. Aila is also a fisherman, a Hawaiian activist and a candidate in the Democratic gubernatorial primary.

"That area where the grenades are all over the place on the bottom is a good octopus area," Aila said. "So when you go and poke octopus in that area, and you go and dive and you go after the squid, you have to be careful. You don't shoot randomly because there are grenades down there."

Aila added he's also heard of torpedoes lying on the seabed off Waianae.

He called the NOAA survey good start and said he was grateful the area was being assessed. He said if harmful weapons were found, the public would demand that the Department of Defense take "the next step."

U.S. Rep. Ed Case, a Democrat whose district includes Waianae, said he was happy with the way the Pentagon and NOAA have responded. But he added Ordnance Reef is only "the tip of the iceberg" of dumping sites that would need to be surveyed.

"The [Department of Defense] is doing exactly what needs to be done. The most immediate challenge is to identify and quantify shallow water munitions," Case said.

He said any weapon that was active should be removed and discarded from Ordnance Reef.

U.S. Rep. Neil Abercrombie, D-Hawaii, who together with U.S. Sen. Daniel Akaka has submitted legislation calling for an analysis of chemical weapons in and around Hawaii, said the military and NOAA were dealing with the weapons "in good faith" and "in good order."

Akaka, D-Hawaii, said "I am glad that the Army continues to be proactive in this matter as required in the legislation that Representative Abercrombie and I introduced this February. I look forward to reviewing the complete report."