The first suicide bomber detonated a truck bomb at the building serving as a barracks for the 1st Battalion 8th Marines (Battalion Landing Team – BLT 1/8) of the 2nd Marine Division, killing 220 Marines, 18 sailors and 3 soldiers, making this incident the deadliest single-day death toll for the United States Marine Corps since the Battle of Iwo Jima in World War II and the deadliest single-day death toll for the United States Armed Forces since the first day of the Tet Offensive in the Vietnam War.[1][better source needed] Another 128 Americans were wounded in the blast; 13 later died of their injuries, and they are counted among the number who died.[2] An elderly Lebanese man, a custodian/vendor who was known to work and sleep in his concession stand next to the building, was also killed in the first blast.[3][4][5] The explosives used were later estimated to be equivalent to as much as 9,500 kg (21,000 pounds) of TNT.[6][7]