NEW ORLEANS (AFP) -- A drill rig working on a relief well is returning to the site of the Gulf of Mexico oil spill after an oncoming storm system weakened, a BP Plc (BP) spokesman told AFP Saturday. "The Development Driller 3 is on its way back," BP spokesman Bryan Ferguson said. "It's the one that's drilling the first relief well and its the most critical one and it is turned around and is headed back right now." The rig was disconnected from the spill site ahead of Tropical Storm Bonnie, which has now weakened to a tropical depression. "The assessment was made that the storm intensity has decreased," Ferguson said. "So the decision was made overnight to return the DD3." (END) Dow Jones Newswires July 24, 2010 09:36 ET (13:36 GMT)