"We have to subject our system to some scrutiny to see if it works for us," House Speaker Nancy Pelosi, D-San Francisco, said during a news conference at Crissy Field in San Francisco.
One possibility would be to require double-skins on fuel tanks or some sort of partial double hull on cargo ships. In response to the disastrous Exxon Valdez spill in Alaska in 1989, all oil tankers in U.S. waters must have double hulls by 2015.
Another would be to make the Coast Guard's vessel transport system more stringent for ships entering and leaving ports, like the air traffic control system.
Rep. George Miller said that requiring cargo ships to have escort boats, stockpiling cleanup equipment more broadly across the Bay Area or spending hundreds of millions of dollars to remove hazardous underwater rocks should also be considered.
Because of the strong currents in San Francisco Bay, the Martinez Democrat said the focus should be on prevention because any spill will spread fast, he said.
"Once the oil enters the water, you've lost the battle," he said.
Though the Cosco Busan did not have a double hull, it did have an added layer of safety: a tugboat, which is required in the Bay under state law for oil tankers, but
The tug escort can push or pull ships away from trouble if they lose power, lose steering or have other problems.
Yet despite that precaution, the tugboat apparently was not asked or may have been unable to steer the vessel clear of the collision in time.
With the cause of the accident still a mystery, the fact that the tug was not able to save the ship could indicate that the pilot and crew did not realize the ship was dangerously off course, experts familiar with the case said Monday.
"The tug works at the direction of the pilot. Judging from what I've heard about the radio transmissions, it sounded like he thought he was where he wanted to be," said Capt. Peter McIsaac, port agent for the San Francisco Bar Pilots Association in San Francisco.
Cargo ships and chemical tankers are not required to have tug escorts. But larger cargo ships often do when they leave the Port of Oakland to help them stay in the narrow shipping channel between Oakland and the Bay Bridge, said Commodore John Keever of the U.S. Maritime Service.
"I would suggest that they didn't know they were going to hit the bridge. They didn't realize they were so close," said Keever, who also works as vice president of the California Maritime Academy.
Called "Revolution," the tugboat roped to the stern of the Cosco Busan was built only two years ago and is one of the strongest tugboats in San Francisco Bay with 5,000 horsepower.
It is owned by AmNav Maritime Services, an Oakland company.
On Monday, its president said the company was not being considered as potentially at fault.
"We have met with the Coast Guard. We have been informed they are not looking at AmNav or our tug as a party of interest," said Milt Merritt. "But we will continue to cooperate fully if we are called upon."
Meanwhile, the Coast Guard has detained the Cosco Busan because of the gash in its hull and an unspecified deficiency with the ship's crew.
Rear Adm. Craig Bone, the Coast Guard's top official in California, said a preliminary investigation found a problem with the crew's "bridge resource management team" but would not say exactly what the problem was or whether he thought it contributed to the spill.
The Coast Guard said the ship's crew was in San Francisco Bay for the first time but found no problems with the vessel itself.
"Unless the ship fails, there is no excuse to hit a fixed object," Bone told members of Congress as they looked out on a lagoon below the Golden Gate Bridge Monday morning.
Bone said the Coast Guard has asked the National Transportation Safety Board to determine the cause of the spill in order to remove the perception the Coast Guard was investigating itself.
The U.S. Attorney's Office is investigating whether civil penalties or a criminal prosecution are warranted. Hearings are also expected in Congress and in the state Legislature.
The Coast Guard has been criticized for initially underestimating the size of the spill Wednesday morning at only 140 gallons and for being slow to alert local government officials and the public once it knew the spill had grown to 58,000 gallons. Of that amount, 12,270 gallons have been recovered.
The spill occurred when the Cosco Busan was leaving the Port of Oakland bound for South Korea when it struck the Bay Bridge, opening up a gash nearly 100 feet long on a ship that is the length of three football fields.
Bone said equipment to measure the fuel level was smashed and it was not until the fuel was transferred from the damaged tank to a working tank that the size of the spill could be estimated.
Still, it took four hours from the time the Coast Guard knew the size of the spill and when the agency notified the city of San Francisco and other local governments.
"If your grandchildren were playing in the sand here, you would want to know four hours earlier so you could go home," Pelosi said.
Bone acknowledged the Coast Guard's delays but insisted the cleanup efforts were quick and aggressive.
"There's no excuse for the four-hour gap between when we knew the amount (of fuel spilled) and when we notified the city," Bone said, adding later, "A vessel hit the bridge. We knew it could be catastrophic."
More than two dozen beaches, including popular destinations such as Stinson Beach, Muir Beach and Angel Island, remain closed. Point Isabel and a coastal access point in Point Richmond were closed in Contra Costa.
As of Monday, 545 live oiled birds had been collected, 34 of which died. Another 369 dead birds had been collected, not all of which were oiled. Some of the dead birds could have died from other causes.
Cleanup officials said very little recoverable oil remains on the water and that their efforts on Monday began shifting from cleaning up the water to cleaning up the shore.
The cleanup now involves 1,500 people and more than 75 vessels, including 18 fishing vessels. At Ocean Beach, 300 newly trained volunteers joined the cleanup effort on Monday, as did 100 more volunteers at the Berkeley Marina.
Bone said the Coast Guard was preparing to release recordings and transcripts of radio transmissions to and from the ship, but that those materials were being reviewed prior to release.