WASHINGTON -- Advances since the 1989 Exxon Valdez oil spill have helped prevent additional mishaps as well as put in place the tools for a quick response to future oil spills, environmental regulators said Friday during a program to mark the 20th anniversary of the environmental disaster.

There's no better example than the SKS Satilla, a 3-year-old Norwegian tanker that hit a submerged oil rig last week off the coast of Texas, said Rear Admiral Sally Brice-O'Hara of the U.S. Coast Guard, who was stationed in Kodiak when the Exxon Valdez ran aground. The double-hulled Norwegian tanker didn't spill a drop in the collision, but had it not been built to post-Exxon Valdez standards, the resulting disaster would have been much worse, Brice-O'Hara said.

"A potential environmental catastrophe was averted, primarily because the SKS Satilla was a double-hulled tanker and the damage along the bottom ruptured only the ballast water tank, not the cargo tank," she said. "With a single skin, the results would have eclipsed the Exxon Valdez spill."

Friday's event in Washington was put on by the National Oceanic and Atmospheric Administration and was part commemoration and part memorial of the Exxon Valdez spill; the tanker ran aground on Bligh Reef in 1989, spilling 11 million gallons of oil into Prince William Sound.

The oil spill exposed a level of corporate and regulatory complacency that the state of Alaska, oil producers and U.S. regulators can never return to, said Sen. Lisa Murkowski, R-Alaska.

"Alaskans will never forget that morning, waking up to hear about the worst oil spill in U.S. history," Murkowski said. "We became acutely aware of how woefully unprepared we were."

The past two decades may have seen significant progress in scientific knowledge as well as oil spill response and cleanup, Murkowski said, but "we simply cannot allow ourselves to become complacent again."

Prince William Sound is now home to more oil spill cleanup equipment than any port in the world, said Donna Schantz, acting director of the Prince William Sound Regional Citizens Advisory Council. They have radar systems with iceberg detection, high-performing escort tugboats, and 900,000 barrels of storage capacity for recovered oil.

They place a high priority on having two tugs escort all tankers through the sound and 17 miles into the Gulf of Alaska, Schantz said. Although the tug escort isn't required for double-hulled tankers, they will continue to provide it even after all tankers are required to have double hulls in 2010.

Going forward, NOAA and the Coast Guard continue to have concerns about ships carrying freight with large fuel tanks that don't have the double hull protection of the oil tankers. They also are concerned about the effects renewable energy installations and expanded offshore oil and gas exploration along coastlines in portions of the U.S. where it currently isn't taking place, said Dave Westerholm, the director of NOAA's office of Response and Restoration.