From Disaster Research Center, Aug 1972:
At approximately 5:15 a.m. on March 19, 1972, a southbound tow of nine barges hit the head of Shippingport Island in the Ohio River, an area just north of the heart: of Louisville, Kentucky. Upon ramming the island, four of the nine barges broke loose and drifted downstream on the north side of Shippingport Island through an area known as the Falls of the Ohio. [One] barge was immediately recovered; a second barge with a cargo of chrome ore was lost and presumed sunk; a third barge laden with sulfuric acid came to rest next to a hydroelectric plant making up part of McAlpine Dam and wag retrieved some days later. The fourth barge, and the one of concern in this study, carrying 640 tons of liquid chlorine in four pressurized cylinders, lodged partly submerged in the second of four tainter gates in the McAlpine Dam.
by John S. Fitzpatrick & Jerry J. Waxman