( CNN ) -- Preliminary lab results show two oil samples taken on the Louisiana coast are from BP 's 2010 Gulf spill , state officials said Thursday . The oil was discovered on Elmer 's Island , said spokeswoman Olivia Watkins of the state Coastal Protection and Restoration Authority . `` There are additional samples in the testing pipeline . However , the proximity of these other oil mats is very close to those that tested positive for BP oil , '' she told CNN in an e-mail . Samples also are being taken at other locations on the coast , according to Watkins . In the wake of Hurricane Isaac , state officials reported tar balls and a large oil mat along the Gulf shore south of New Orleans . It 's not clear whether the hurricane swept tar balls ashore or exposed them under the sand , U.S. Coast Guard Petty Officer Bill Colclough said . The U.S. Coast Guard reported finding three oiled birds in the area on Monday . BP said Wednesday it was heading to the coast to test whether tar balls and oil are from the 2010 spill . BP spokesman Ray Melick said the area is one where BP teams were already helping with cleanup from the 2010 spill before Isaac arrived . `` There 's a lot of oil out there that may not be ours , '' Melick said . The coastal protection authority is coordinating with other state agencies to test the contents . The area is near Fourchon Beach and Grand Isle . The same area was heavily affected by the spill , which happened in April 2010 after an explosion aboard the Transocean Deepwater Horizon oil rig in the Gulf of Mexico . BP had contracted the rig , which had 126 workers on it , 11 of whom are presumed dead . Colclough said pollution after a hurricane is expected because the force of the storms can bring oil and other debris to the surface . CNN 's Joe Sutton and Melissa Gray contributed to this report .
Preliminary tests from Louisiana Oil found oil from BP spill . Tar balls and an oil mat have been found since Hurricane Katrina . BP says it was already working on wells in the area before the storm .