Navy explosive ordnance disposal technicians Monday detonated two World War II-era 100-pound gravity bombs and removed other ordnance from the highly-traveled channel between Lanikai and Mokulua North, otherwise known as Mokunui Islet.

The explosion surprised some in the area. A work boat was visible at the spot more than halfway to the island popular with kayakers and stand-up paddlers.

A snorkeler apparently found the munitions and contacted the Coast Guard, who in turn got in touch with the Navy.

The 100-pound bombs had fuses and were detonated in place because of the possible danger. About eight other bombs or pieces of ordnance without fuses were removed and taken in an inflatable boat to Bellows for transport to Pearl Harbor or Schofield Barracks for demolition.

Officials said it’s not known how the munitions got to where they were found, but may have been dropped during wartime exercises.

All of the offshore islets are state wildlife sanctuaries. A perimeter path around Mokulua North is the only section visitors are allowed to traverse.

Unexploded ordnance from training before and after the Dec. 7, 1941, attack that launched America into World War II is routinely discovered in Oahu’s waters and on land.