A beachgoer in Rehoboth Beach walked up to a lifeguard in July with two strange objects in his hand and a stranger request on his lips.

He was carrying rusty old artillery shells he found in the sand.

"Can I keep them?"

They were live. The Delaware beach was evacuated. A bomb squad blew them up.

The country's coastlines are littered with unexploded bombs, rockets and shells that regularly wash up on shore, according to military officials.

While the Army dumped chemical weapons mostly in deep water - as detailed in a Daily Press investigation published Sunday and Monday - the Navy used to throw surplus high-explosive, so-called conventional ordnance overboard, sometimes in relatively shallow water.

These "over-the-side," "routine" dumping operations were official Navy policy from 1952 to 1964, according to a previously undisclosed Navy report obtained by the Daily Press.

After that, the Navy disposed of 31 million pounds of old bombs and rockets for six years in spectacular fashion: Loading them onto ships and blowing them to smithereens off the coasts of eight states.

One of those ships was detonated off the coast of New Jersey in 1964 and produced a blast so massive it was picked up by seismic sensors on land, many miles away, and threw unexploded ordnance in all directions. A year later, a ship blown up off Virginia Beach sent a plume 600 feet into the air - higher than the Washington Monument.

The practice stopped when the Navy lost a weapons-packed ship in the fog in 1970.

Nautical charts sometimes, but not always, mark the locations of conventional ordnance in the ocean. The discarded weapons are extremely hazardous. The military does not know where they all are located. Records are sketchy, at best.

"We've come to the conclusion we need to do a complete archival search," said J.C. King, a retired Army colonel who was chief of ordnance and now works for the Army on explosives issues. "There are some vague reports. The Navy has some hand-written documents. It is logical to assume an archival search will come up with something. But it is possible it will show up nothing."

King has spent the last year trying to find military ocean-dumping records after a clam dredging operation a mere 20 miles from the coast of New Jersey tapped into an undocumented ordnance disposal site that included chemical weapons.

His research uncovered little more than the fact that ocean dumping was standard Navy practice for at least two decades, and that a detailed report exists that documents a six-year, large-scale Navy ordnance disposal operation in the 1960s.

Two weeks ago, the Army authorized the Army Technical Center for Explosives Safety to do a military-wide review of existing records to identify where ordnance - both chemical and conventional - was dumped and when.

This would make possible a future assessment of the risks the ordnance poses to beachgoers, boaters and commercial fishing operations - something the military has never done. The Army is in charge of explosives used by all the military services.

Within the last three years, rockets have washed up on Assateague Island in Maryland; an unexploded antiaircraft shell was found in Dewey Beach, Del.; and a plan to dredge San Diego's harbor was put on hold when unexploded ordnance and a depth charge were discovered near the shoreline.

A beach replenishment project in Virginia Beach last summer off Dam Neck Naval Reservation sucked up three truckloads of old ordnance from the ocean floor within yards of the shoreline, said Roy Hunt, a Navy master chief and explosives expert based in Norfolk.

That was just the small stuff that could fit through the hose that sucked sand off the seabed and sprayed it onto the beach, Hunt said. Rockets and other large munitions remain on the ocean floor at that location, he said.