Three undetonated explosives were discovered by a father and son who were beachcombing near Long Beach in Noyac on Sunday.
Tom W Ratcliffe and his 6-year-old son called 911 and Southampton Town police responded, who in turn called town fire marshals.
Fire Marshal John Rankin said Monday morning that Suffolk County Police Emergency Service was called in to take the explosive material away and dispose of it elsewhere.
The explosives were found in large rocks put in place as a revetment at the north end of Long Beach to shore up the area following severe erosion from Superstorm Sandy.
Ratcliffe found two of the explosives in a man-made hole in of one of the rocks, and the third was nearby. Rankin believes the explosives came from the quarry where the large rocks originated. Similar explosives were found in North Haven last year by the ferry terminal, and are also believed to have come from a quarry.