GOLETA, Calif. — More than 6,000 gallons of oil has been raked, skimmed and vacuumed from a spill that stretched across 9 miles of California coast, just a fraction of the sticky, stinking goo that escaped from a broken pipeline, officials said.

Up to 105,000 gallons may have leaked from the ruptured pipeline Tuesday, and up to 21,000 gallons reached the sea off the Santa Barbara coast, according to estimates. The environmental impact still is being assessed, but so far there is no evidence of widespread harm to birds and sea life.

Federal regulators investigated as workers in protective suits shoveled the black sludge off beaches and boats towed booms into place to corral the two slicks.

The chief executive of Plains All American Pipeline LP, which runs the pipeline, visited the spill site Wednesday and apologized.

“We deeply, deeply regret that this incident has occurred at all,” Chairman and CEO Greg L. Armstrong said at a news conference. “We apologize for the damage that it’s done to the wildlife and to the environment.”