Pollution of navigable waters. : Hearings before the Committee on Rivers and Harbors, House of Representatives, Seventy-fourth Congress, second session [i.e. Seventy-fifth Congress, first session], on H.R. 2711, to create a division of water pollution control in the United States Public health service, and for other purposes; H.R. 3419, to prevent pollution of the navigable waters of the United States and for other purposes. March 17, 18, 19, and 24, 1937.