A ruptured pipeline spilled as much as 105,000 gallons of crude oil along the coast of Santa Barbara County, California.
Out of the 105,000 gallons spilled, an estimated 21,000 gallons is said to have flowed into the Pacific Ocean, according to the Los Angeles Times. A stretch of Refugio State Beach was also affected by the leak.
NBC Los Angeles reports Governor Jerry Brown declared a state of emergency in Santa Barbara on Wednesday.
The 11-mile pipeline, owned by Plains All American Pipeline, began experiencing mechanical difficulties at two pump stations around 10:45 am on Tuesday.
Workers noticed pressure problems soon after and manually shut the line down at 11:30 am.
A couple hours later, however, a worker who was reportedly inspecting an area with an odor discovered the rupture.
The US Coast Guard was able to stop the leak by 3 pm.
It isn't clear exactly how many gallons were released since the estimation is based on the elevation of the 24-inch-wide line and the speed at which oil can stream through it.
Plains All American said the oil was flowing at maximum capacity at the time of the spill.
The specific cause of the rupture isn't clear, but investigators are expected to find an answer when they excavate the line.
Plains All American Chairman Greg Armstrong offered his sincerest apologies, according to CNN.
The US Coast Gaurd claims two oil slicks measuring a combined nine miles are currently blanketing Refugio Beach.
The cleanup operation is expected to take at least three days.
Skimmers and boom vessels collected over 6,000 gallons of oil already.
Wildlife in the area was also affected by the oil spill.
Jim Milbury, a spokesman for NOAA Fisheries, told the Los Angeles Times wildlife officials said the oil doesn't appear to have touched any marine mammals.
Plains All American was awaiting the results of an integrity check conducted two weeks ago when the rupture occurred.
Citations: Wildlife pristine beaches focus of aggressive oil spill cleanup (CNN ), State of Emergency Declared for Oil Spill Off Santa Barbara Coast (NBC Los Angeles), 105000 gallons of oil may have spilled in Santa Barbara County (The Los Angeles Times)