Abstract: A gas venting floating cover for a liquid container, the cover including a continuous sheet of flexible material adapted to lie upon the liquid in the container in coextensive relationship therewith for attachment to the container sides in fluid tight relationship. Flotation blocks are attached to the cover to define gas collection spaces for receiving gas evolving from the liquid. The flotation blocks include first and second strings of blocks transversely spaced apart to define a longitudinal passage, certain of the blocks of each string being longitudinally spaced-apart to define transverse passages in communication with the longitudinal passage. A gas collection conduit is attached to the first and second strings in coextensive overlying relation to the longitudinal passage and includes gas admission openings, and a plurality of transverse straps extend between the first and second strings of blocks to constrain them against separation under the weight of the gas collection conduit.