On November 26, 2004, the "Athos I", a single-hull oil tanker carrying of oil that had traveled from Venezuela was maneuvering to dock at a Citgo dock on the Delaware River near its refinery at Paulsboro. An anchor in the river's bed, known to have been there since at least 2001, caught on the ship's hull and tore a gash into it, releasing more than of oil into the river. The spill spread downstream affecting the shoreline in more than three states (Pennsylvania, New Jersey, and Delaware), killing over 11,000 birds, temporarily shut down the Salem Nuclear Power Plant, and halted commercial use of the river for several weeks during cleanup efforts. At the time, it was considered the second worst oil spill in the United States following the "Exxon Valdez" oil spill, with cleanup costs over . The spill led to passage of the Coast Guard and Maritime Transportation Act of 2006 which among provisions, tripled fines resulting from oil spills from single-hulled vessels to encourage double-hull use, as well as requiring those with knowledge of obstructions in waterways to inform the Coast Guard for immediate removal.