Some 126,000 gallons or 3,000 barrels of heavy crude spilled into the Pacific Ocean between Huntington Beach Pier and Newport Beach, a distance of more than five miles.

The slick, covering around 13 square miles and one of the worst in Californian history, has killed wildlife, contaminated wetlands and fouled popular beaches.

An investigation into the pipeline breach that caused it is under way.

Kim Carr, the mayor of Huntington Beach, called the spill an “environmental catastrophe” and a “potential ecological disaster”.

Crews led by the US Coast Guard deployed skimmers and floating barriers known as booms to try to stop further oil reaching into the wetlands and the Bolsa Chica Ecological Reserve.

The US Coast Guard, working with local and state agencies, flew airplanes to assess the spill and had hired contractors to clean it up.

“Wildlife is dying. It’s very sad,” Orange County Supervisor Katrina Foley told CBS New. She said the reserve had also suffered “significant damage”.

A stretch of coastline has been closed to swimming. Aerial footage sowed the estent of the spill’s spread

Amplify Energy Corp, which owns three off-shore platforms, said it stopped operations and shut its pipeline on Saturday.

CEO Martyn Willsher said the pipeline had been suctioned to ensure that no more oil would spill.

Cottie Petrie-Norris, a Democratic state assembly member representing some areas affected by the spill, said she had “huge concerns” about the extent of the damage to the environment, communities and local economy.

She told CNN the spill was a “call to action that we need to stop drilling off our precious California coast.”

© Provided by Evening Standard Cleanup contractors deploy skimmers and floating barriers known as booms to try to stop further oil crude incursion (AP)

Oil production off California’s coast has declined sharply since its peak in the 1990s, in part due to the state’s strict environmental rules.

Democratic Governor Gavin Newsom said he wants to end oil drilling in the state by 2045.

Offshore drilling was restricted in the state after a devastating 1969 oil spill off the coast of Santa Barbara that dumped 80,000 barrels into the ocean.

More recently another spill off Santa Barbara in 2015 sent as much as 2,400 barrels onto the shore and into the Pacific.

Oceana, an ocean conservation group, also called for an end to offshore oil and gas drilling.

Jacqueline Savitz, Oceana’s chief policy officer, said in a statement: “This is just the latest tragedy of the oil industry. It’s well past time to prevent future oil spills by permanently protecting our coasts from offshore drilling.”