126,000 gallons of oil spilled into the waters off Orange County.
Officials say it happened when an underwater pipeline owned by Amplify Energy started leaking oil late Friday or early Saturday.
The pipeline and three oil platforms it serves have been shut down.
The U.S. Coast Guard says more than 3,000 gallons of oil have been recovered from the water and nearly 5,400 feet of boom has been deployed.
No word yet on what caused the oil spill.
An investigation is underway.