At 11.17 hours on 28 Feb, 1942, the unescorted and unarmed Oregon (Master Ingvald C. Nilsen) was attacked by U-156 with the deck gun about 150 miles northeast of Mona Passage while steaming completely blacked out on a zigzag course at 10 knots. The first shell hit the starboard side in the quarters of the master and the second destroyed the radio shack. After disabling the radio the U-boat circled the tanker and fired shells at point blank range into the waterline during 75 minutes. Fire broke out on the bridge and the stern and a boiler exploded but the cargo never caught fire. The tanker sank by the stern about four hours after the initial attack.
The eight officers and 28 crewmen abandoned ship in one lifeboat and one raft. They abandoned ship on the starboard side while the U-boat fired shells into the port side. The master, two officers and three crewmen died during the attack. The 26 survivors in the lifeboat made landfall near Puerto Plata, Dominican Republic on 4 March. The four survivors on the raft were picked up by the Gulfpenn five and a half days after the attack.

Some survivors reported that two U-boats shelled the vessel and that some men were machine gunned when they tried to lower the port boats. A man who jumped overboard reported that a U-boat attempted to run him over. There are no proofs for this reports, but fact is that only one U-boat attacked and the men lost were apparently killed in the initial shelling of the bridge and radio shack.