On 30 March 1972, the North Vietnamese launched their Easter Offensive, a conventional invasion of South Vietnam. In response, the USAF launched Operation Linebacker, the first sustained bombing of North Vietnam by the US since November 1968. Upon re-opening the base for Linebacker, most of the barracks had been stripped of all plumbing and electrical fixtures after the 1970 closing. Most SAC enlisted personnel were housed in the recovered dorms with one shower and one toilet set up by the "Red Horse" civil engineer teams and a few operating light bulbs in the large open-bay dorms. TAC enlisted personnel lived in a large "tent city" made up of line after line of General Purpose medium and large canvas tents.