An oil spill was reported at Refugio State Beach, about 20 miles west of Santa Barbara, Tuesday, May 19, 2015.

SANTA BARBARA, Calif. (KABC) -- A ruptured 24-inch pipeline spilled oil into the ocean off Refugio State Beach, about 20 miles west of Santa Barbara, which spread across 4 miles of coastline.A citizen reported the leak at about noon Tuesday coming from the pipeline off the 101 Freeway. The pipeline, owned by Santa Maria-based Plains All-American Pipeline, was on land, and the oil flowed from a culvert into the waters.The culvert was later blocked and the leak was stopped, Plains All-American Pipeline's officials said. It was initially reported an estimated 21,000 gallons of oil spilled into the ocean, but an exact amount was unknown."Plains deeply regrets this release has occurred and is making every effort to limit its environmental impact. Our focus remains on ensuring the safety of all involved," Plains All-American Pipeline released in a statement.Plains All-American Pipeline was also involved in an oil spill in Atwater Village in May 2014, when a burst pipeline spewed about 10,000 gallons of crude oil over a 1/2-mile area.The U.S. Coast Guard was monitoring clean-up operations. A commercial oil spill response company was helping with the clean-up, Coast Guard officials said.At one point, whales could be seen swimming in the area. Clean-up crews attempted to push the animals away from the oil.Concerned citizens also scoured the beaches looking to rescue any animals that may have been caught in the thick, gooey oil. So far, there have been no reports of any injured wildlife, but photos from Santa Barbara-based online news website Noozhawk showed birds caught in the muck.Officials with the Coast Guard said the sludge is considered a "medium-sized" spill.Santa Barbara County Office of Emergency Management, Exxon, the Santa Barbara County Fire Department and California Department of Fish and Wildlife were on scene.About 20 barrels of oil have been retrieved so far.The public was urged to avoid the area during clean-up. Refugio Beach and its campground were closed until further notice. Officials said the oil could spread another 2 to 4 miles south down the coast due to the winds and surf.