The Army yesterday warned people to stay away from small, pellet-like items that have been washing up on Ma'ili Beach, after confirming they are flammable propellant grains used in munitions.

Propellant grains are used in rockets and artillery, burning like the gunpowder in a bullet to generate explosive thrust, according to several Internet references.

"I actually lit one on the concrete with a match and said, 'Gee — this is very flammable!'" said Wai'anae Boat Harbor harbormaster William Aila. "There was a rapid reaction and a sort of pinkish flame that came out of it. It burned down pretty fast."

Aila said that over the years he has heard of such pellets washing ashore from time to time. He said he became concerned after he heard that some people mistook the grains for coral beads and were collecting them to make necklaces.

U.S. Army Garrison Hawaii officials were trying to determine where the pellets came from.

A preliminary examination led to the possibility that the propellant is Navy in origin, and possibly was used in large-bore guns. The Navy said it was looking into the discovery.

The pellets are cylindrical and about one inch long and one-fourth to three-eighths of an inch in diameter, the Army said. They range in color from olive green to brown.

They are highly flammable and extremely sensitive to friction and static electricity, the Army said. It advised people who have them to place them in water.

Aila asked some people at Ma'ili Beach Park who had found and collected the beads if he could have a few.

On Wednesday, Aila e-mailed the National Oceanic and Atmospheric Administration about the suspicious pellets. Yesterday morning, he got a call from Schofield Barracks, saying Army experts wanted to examine the beads. Three Army officials went to the Wai'anae Boat Harbor and picked up the grains.

Aila began advising some who had collected the grains at Ma'ili Beach Park not to handle them any longer because they were highly flammable and dangerous.

Venise Lewis, one of those who had picked up the pellets on the shore, said she already knew it. She said a friend had set one of the beads on fire.

"And it blew up," Lewis said. "So she took the beads out of her tent."

Lewis said the pellets had been washing ashore for a long time. But she stopped collecting them after her friend ignited one.

Reach Will Hoover at whoover@honoluluadvertiser.com.