Cleanup workers using 17 vessels are continuing efforts to remove 100,000 gallons of  crude oil spilled into the ocean and on the land 20 miles north of Santa Barbara, California, according to news sources. As of Thursday night, some 9,500 gallons of oily water had been skimmed from the ocean.Officials say the clean-up -- which is complicated by currents, tides and the wind -- could take months.

Gov. Jerry Brown has declared a state of emergency for Santa Barbara County.

One of the worst violators

The oil was dumped from a broken pipeline owned by Plains All American Pipeline, which issued a statement saying it "deeply regrets" the spill.

"We apologize for the damage that has been done to the wildlife and to the environment, and we're very sorry for the disruption and inconvenience that it has caused the citizens and visitors of this area," said Plains All American Pipeline Chairman Greg Armstrong.

Pelicans, sea lions, countless lobsters, kelp bass and marine invertebrates are among the fatalities so far.

Plains All American Pipeline is among the worst violators listed by the U.S. Pipeline and Hazardous Materials Administration and surpassed all but four of more than 1,700 operators in reporting safety and maintenance infractions, the federal agency said.

The company has 175 federal safety and maintenance violations since 2006, responsible for more than 16,000 barrels in spills that have caused more than $23 million worth of property damage.

Environmentalists, the Coast Guard, state parks officials and county emergency officials are all participating in the cleanup, which is utilizing boats provided by the nonprofit group Clean Seas.

Migrating whales and holiday beachgoers

"To see this level of spill into such a sensitive and treasured environment is devastating to watch," said the Santa Barbara-based Environmental Defense Center (EDC) in a statement. The EDC said the incident potentially endangers many species of whales that migrate through the area.

The affected coastline has many beaches that are popular with campers and would, under ordinary circumstances, be crowded for the Memorial Day holiday weekend. Officials could not say when the beaches would reopen.

The cause of the spill remains under investigation.