A 24 inch subterranian crude oil pipeline carrying up to 150 000 barrels per day ruptured along the southern California coast spilling an estimated 21 000 gallons (more than 500 barrels) of oil into the Pacific Ocean.

According to Plains All American Pipeline L.P., the pipeline operator, the pipeline runs under U.S. Highway 101, transporting crude from an inland facility owned and operated by ExxonMobil. Plains shut down the pipeline to stop the flow of oil and the culvert where the leak was discovered has been blocked so no additional crude can reach the water, the company said.

The leak was first discovered by California residents who noticed a "pungent, acrid smell" while strolling along the Refugio State Beach near Santa Barbara.

Officials from the Santa Barbara Fire Department evacuated people from Refugio State Beach after the spill was reported around 1 p.m. local time. Refugio State Beach is situated on a cove teeming with wildlife about 140 miles northwest of Los Angeles.

No injuries to humans have been reported, Plains said. So far, there have been no reports of injured or oiled birds or other wildlife, said Santos Cabral of the California Fish and Game Department. Yet, with the true volume of oil spilled still being measured, no definitive statements regarding the impact on the state's wildlife can be made.

Clean-up efforts started Tuesday, with 1,500 feet of boom — a kind of floating curtain — deployed on the water to trap oil floating at the surface. So far, only 20 barrels of oil have been skimmed off the water, according to the Coast Guard.

“I want to manage your expectations. This could take some time,” says Capt. Jennifer Williams, the federal on - site coordinator working with the Coast Guard. She added that the unified joint command responding to the spill does not intend to use chemical dispersants to dissolve the oil in the water.