Retired Coast Guard Adm. Merlin O'Neill, 82, commandant of the Coast Guard from 1950 to 1954 and a decorated veteran of World War II campaigns in the Pacific and the Mediterranean, died of cardiac arrest Saturday at the Naval Hospital at Patuxent River, Md.

During World War II, adm. O'Neill was skipper of the attack troop transport Leonard Wood during amphibious operations in the Gilbert and Marshall Islands in the Pacific and in Sicily and North Africa.

During one run of 12 days and 3,000 miles from Norfolk to Casablanca, the Leonard Wood arrived in port five minutes late. Asked to comment, the captain said, "I guess we hit an adverse current after reversing the engines for the unloading."

The Leonard Wood carried troops, war material, and once a contingent of prisoners-of-war from the Afrika Corps. She was in action against enemy aircraft, shore batteries, mines and submarines. The end of the war saw Adm. O'Neill with a Legion of Merit and the Leonard Wood with a Navy Unit Commendation.

Asked by a reporter how his ship earned the commendation, Adm. O'Neill said, "Nothing special, we just had one hell of a time."

Near the end of the war, Adm. O'Neill was placed in command of a Coast Guard amphibnious training facility in North Carolina. He then became chief of the Coast Guard's 5th District, which included the captaincy of the Port of Baltimore, and marine inspection, training and recruitment duties. His next assignment was as assistant commandant of the Coast Guard, a post he held for four years before becoming commandant on Jan. 1,1950.

Adm. O'Neill was a native of Ohio and a 1921 graduate of the U.S. Coast Guard Academy at New London, Conn. Before World War II, he served aboard cutters and destroyers patrolling sea lanes in the North Atlantic and had three tours of duty in the Bering Sea, guarding whaling stations and sealiang grounds.

He was a technical adviser to the U.S. delegation to the International Whaling Conference in London in 1937. The conference was called to regulate the killing of the whales.

Adm. O'Neill had lived in Lusby, Md., since retiring from active duty in June 1954.

Survivors include his wife, Esther, of Lusby; two daughters, Patrica T. Penn of Thurmont, Md., and Marilyn L. O'Neill of West Chester, Pa.; a brother, Edwin, of California, and three grandchildren.