The major oilspill was thought to be caused by a suspected leak in an underwater pipeline
One of the largest oil spills in recent southern California history has fouled popular beaches and killed wildlife in what the city's mayor described as an "environmental catastrophe".
An emergency clean-up effort is under way in Huntington Beach, California, after at least 476,000 litres of oil spilled into the waters off Orange County.
An equivalent of some 3,000 barrels of oils spread over an area covering 13 square miles, with officials confirming birds and fish died after being caught in the muck.
Huntington State Beach is home to a number of species of birds, including gulls, willet, long-billed fletcher, elegant teens and reddish egret, which are a rarity on the west coast of the US.
Huntington Beach mayor Kim Carr said the affected beaches - in the town known as Surf City USA - are likely to remain closed for weeks or even months.
"In a year that has been filled with incredibly challenging issues, this oil spill constitutes one of the most devastating situations that our community has dealt with in decades," she said. "We are doing everything in our power to protect the health and safety of our residents, our visitors and our natural habitats. "In the coming days and weeks we challenge the responsible parties to do everything possible to rectify this environmental catastrophe."
The spill fouled the strand in Huntington Beach, the town known as Surf City USA
An investigation into the pipeline breach that caused the spill is under way.
It is believed to be one of the largest oil spills in the state's recent history, according to the Associated Press.
Crews led by the US Coast Guard deployed skimmers and floating barriers known as booms to try to stop further incursion into protected wetlands and the Bolsa Chica Ecological Reserve.
The coastline was closed from the Huntington Beach Pier nearly four miles south to the Santa Ana River jetty.
Officials cancelled the final day of the annual Pacific Air Show that typically draws thousands of spectators to Huntington Beach, a city of 199,000 residents about 30 miles south of downtown Los Angeles.
The Huntington Beach statement said “while the leak has not been completely stopped, preliminary patching has been completed to repair the oil spill site”, with additional repairs planned.
The spill comes three decades after a massive oil leak hit the same stretch of Orange County coast.
On February 7, 1990, the oil tanker American Trader ran over its anchor off Huntington Beach, spilling nearly 1.6 million litres of crude. Fish and about 3,400 birds were killed.