Oil has been washing up on some Southern California beaches since a leak in an underwater pipeline from an offshore platform sent tens of thousands of gallons of heavy crude into the ocean waters.
The spill fouled the famed sands of Huntington Beach, known as Surf City USA and could keep the ocean and shoreline closed there and in some other communities to the south for weeks.
Here's a look at what happened, who's involved and the aftermath:
Boaters off Orange County and residents of Newport Beach started reporting a petroleum smell in the air and oily sheen on the water a week ago, on Friday.
The following morning the Coast Guard confirmed a spill. The sheen on the ocean was miles wide and crude started washing ashore in sticky, black blobs. The leak occurred about eight kilometres offshore at a depth of about 30 metres and came from a pipeline owned by Amplify Energy. The Houston-based company also owns and operates three nearby offshore platforms that pipe oil into Long Beach.
Oil first washed up on Huntington Beach, including Talbert Marsh, a sensitive wetland. Crude was later spotted down the Orange County coast, in Newport Beach, Laguna Beach and Dana Point. By Thursday tar balls were reported washing up in Carlsbad, San Diego County.
What is the environmental impact?
That will depend on how much oil is out there.
Local officials, who feared an environmental catastrophe at first, have more recently voiced hope that the total spill will be less than initially feared. So far, only a handful of oiled birds have been recovered.
Teams are out searching for affected animals in the spill area and beyond.
Environmentalists say it’s too soon to know how many seabirds, marine mammals and other animals will ultimately be affected by the oily film covering marsh areas and floating on the ocean — or for how long.
Researchers say the impact on animals will take a while to understand. They are just starting to learn about some of the long-term effects from the 2010 Deepwater Horizon oil spill. And many problems remain unseen as oil components build beneath the surface of the ocean.
Out on the water by the rigs, there’s no visible sheen and no stench of oil like the putrid odour that pervaded Huntington Beach in the days after the incident.
How much oil leaked?
It’s still a mystery.
Amplify Energy publicly said no more than 477,000 litres flowed from its pipe. But the company also told federal investigators the total may be 111,300 litres.
On Thursday, the Coast Guard announced its own estimate of at least about 95,000 litres and no more than 500,000 litres.
David Pettit, a senior lawyer at the environmental group Natural Resources Defence Council, finds it hard to believe Amplify doesn’t know how much oil it lost.
“If they know what the flow rate was in the pipeline, and how much the pressure dropped, and for how long, you could calculate that in a matter of minutes,” Mr Pettit said.
How was the leak discovered?
A commercial vessel anchored off Huntington Beach reported to a national hazardous spill hotline staffed by the Coast Guard that it saw a sheen more than three kilometres long just after 6pm on Friday.
A satellite image shot by the European Space Agency indicated a likely oil slick in the area at around 7pm, which was reported to the Coast Guard at 2.06am on Saturday after being reviewed by a National Oceanic and Atmospheric Administration analyst.
The Coast Guard said it did not act on either report, deciding to wait until daybreak because darkness and a lack of technology would hamper its search for oil.
Amplify CEO Martin Willsher said the company did not discover the leak until it saw oil in the water at 8.09am on Saturday.
However, other reports indicate the company had signs of a leak as early as 2.30am on Saturday. Federal regulators said an alarm on Platform Elly alerted a control room operator at that time to a drop in pipeline pressure that could indicate a leak.
The company did not report the leak until 8.55am, according to the California Office of Emergency Services. The company that reported the leak on behalf of Amplify said the incident occurred at 2.30am.
Around the time the company reported the spill, the Coast Guard said it located oil in the water.
Who is responsible?
The cause is under investigation.
Amplify CEO Martin Willsher first suggested on Monday that an anchor from one of the many commercial vessels that use the large Los Angeles-Long Beach port complex might be to blame. The next day the Coast Guard said divers found that a 1,219-metre section of the pipeline was “laterally displaced” by about 32 metres.
It's bent “like a bow string,” Willsher said.
Video of the ruptured pipeline released by the Coast Guard showed a thin 33-centimetre crack that experts said could indicate a slow leak that initially was difficult to detect.
Federal transportation investigators said preliminary reports suggest the failure may have been “caused by an anchor that hooked the pipeline, causing a partial tear.”
On Wednesday, Coast Guard investigators boarded the Rotterdam Express, a massive German-flagged container ship that was assigned an anchorage closest to where the pipeline ruptured.
Hapag-Lloyd, the shipping company that operates the vessel, said the Coast Guard interviewed the captain and crew and was provided access to the logbook showing the ship’s locations. Afterward, the Coast Guard called the company to say the Rotterdam no longer was under scrutiny for the spill, the company said.
The Coast Guard did not comment.