While some barrier islands along the Louisiana coastline were being coated with an oily slick Sunday from the Deepwater Horizon disaster, the barrier islands and mainland shores of Gulf Islands National Seashore still were oil-free, according to the National Park Service.

Park Service spokeswoman Jean Schaeppi said that as of Sunday morning no oil had come ashore and there were no public closures on the national seashore. Some work was continuing to install mechanical booms around some of the seashore's islands with hopes they would keep the beaches free of oil, if it approached them, she said.

According to federal officials, the blowout of the well drilled by the Deepwater Horizon was spewing an estimated 210,000 gallons of oil a day into the Gulf of Mexico, though maps showed the oil still a fair distance away from the national seashore.

For comparison's sake, the National Oceanic and Atmospheric Administration says that, "(T)he largest oil spill in North America occurred in the Gulf of Mexico. The 200-foot-deep exploratory well, Ixtoc I, blew out on June 3, 1979, in the Bay of Campeche, Mexico, releasing 10,000 - 30, 000 barrels (0.4 - 1.2 million gallons) per day for nine months. Nearly 500 dispersant air sorties were flown in Mexico. Manual cleanup in Texas was aided by storms. Though the blowout preventer (BOP, valve designed to seal off a wellhead) failed, injection of metal and concrete balls into the well slowed the release. By the time the well was brought under control in March 1980 by drilling two relief wells to relieve pressure, an estimated 113 million to over 300 million gallons of oil had spilled (10 times the amount of oil spilled by the Exxon Valdez). Oil traveled 800 miles to the north, oiling more than 150 miles of shoreline in Texas and unknown miles of shoreline in Mexico."

National Weather Service forecasts for the Gulf Coast are calling for southeast winds through the weekend that are expected to push surface oil towards shore and hamper surface recovery efforts until a forecast shift on Monday.

Meanwhile, the National Marine Fisheries Service was conducting aerial surveys to develop baseline data of marine life in the region. And NOAA's Assessment and Restoration Division was coordinating seven resource assessment workgroups (birds, mammals and turtles, fish, shoreline habitats, water column injury, data management, and human use) with natural resource trustees from five states and representatives for BP.