The Army, which has the lead in the investigation of the propellant, said efforts will continue to locate and identify the source of the munitions.

The results of a Defense Department survey of munitions dumped in relatively shallow waters off the coast are expected to be released next week, meanwhile, and could lead to a cleanup.

Hundreds of the low-explosive propellant charges, also called grains, likely used to fire high-explosive rounds from large-bore guns, have been collected by Wai'anae Coast residents in recent weeks.

The Army preliminarily identified the explosive as single-base nitrocellulose. Included in the same group are smokeless gunpowders and flares. The one-inch olive, brown and yellow grains have been washing up on Wai'anae Coast beaches for decades.

Cameron Guadiz, an assistant dive instructor with Captain Bruce Scuba Charters who dives regularly off the coast, showed military officials dive spots where he's seen the propellant before.

The location where Navy divers searched in 45 feet of water was likely a dive site called Five-Inch Reef about three-quarters of a mile offshore from the sewage treatment plant, Guadiz said.

Another location where the propellant has been found is called Ammo Reef and is about 200 yards from the Wai'anae boat harbor.

The Army said the Navy divers "experienced significant underwater currents" when they went out on Wednesday. It was unclear if they will head out again to find the propellant.

At the request of the Defense Department, the National Oceanic and Atmospheric Administration, the state Department of Land and Natural Resources, and University of Hawai'i, surveyed 5 square nautical miles off the Wai'anae Coast last June for old munitions.

A NOAA official recently said the propellant charges were not identified in the sweep.