Researchers who studied a stretch of coastline from Alabama's Dauphin Island to the eastern end of Santa Rosa Island in Florida found cleanup efforts still leave behind numerous small tar balls that wind up buried in the sand. It will take longer for these decay. The study by University of South Florida geologists was funded by the National Science Foundation's Rapid Response grant. (Source: NSF, 06/25/10) The Deepwater Horizon exploded April 20, killing 11 workers. Oil and gas have spewed into the Gulf of Mexico since then, despite attempts to mitigate the flow. Oil in various forms has washed into marshes and beaches from Louisiana to Florida, and a slick remains in the Gulf of Mexico.