GRAND ISLE, La. - An Army National Guardsman helps build a levy across a portion of the beach on Elmer's Island, just west of Grand Isle, La., where high tides could allow water from the Gulf of Mexico and oil from the damaged Deepwater Horizon wellhead to flow into the areas' sensitive wetlands, May 21, 2010. While the Guardsmen build the levy, hundreds of workers are cleaning up oil that finally reached the shore a month after the rig exploded, killing 11 people. (USCG) 10Spill0521-G-8744K-012