The pipeline was on land but flowed from a culvert into the waters. The EPA says as many as 500 barrels may have reached the waters off the coast of Refugio State Beach.
"They don't even know the cause, so everything is precautionary at this point," Manhattan Beach Mayor Wayne Powell told ABC 7 News.
Charlene Downey, the on-scene coordinator for the U.S. Coastguard, was asked during a Thursday morning news conference whether the substance might be related to the oil spill last week. She said it's too early to tell whether there's a connection.
"We are continuing to analyze the beaches and try to determine the source of the tar balls and tar patties that washed up on shore yesterday -- It does take time to get those sent to the labs and analyzed so it could be a few days to a week."
Local fishing areas have also been closed until crews are able to remove residual oil from area beaches. Local officials have urged people to stay away from the shoreline but are still welcome to to visit the beach.
Last year, some may recall a bill from environmentalist to permanently ban drilling off the coast of Santa Barbara that failed to pass the State Assembly. The bill's failure to pass marked a major success for Sunset Exploration and drilling partner Exxon Mobile. The two oil companies are seeking the rights to drill for oil on an Air Force property nearby known as the Tranquillon Ridge. Environmentalists have called on the State Assembly to reevaluate the ban that failed in 2014.