The pipeline leak that spilled an estimated 3,000 barrels of crude oil into the Pacific off the coast of Huntington Beach, California, should have been quickly detected, and the flow of oil immediately shut off.

And in fact, the U.S. Pipeline and Hazardous Materials Safety Administration, or PHMSA, said the pipeline operator received a low-pressure warning at about 2:30 am local time on Saturday, October 2.

Reuters correspondent Jessica Resnick-Ault did some digging and found out what was supposed to have happened next.

"When an alarm goes off in a control room, operators are expected to take a number of steps. As soon as they verify that's there's been a spill of more than a barrel, they are supposed to immediately notify federal, state and local response agencies. In fact, a spill of even a single barrel is supposed to trigger a call to the CEO, according to the company's spill response plan, which we obtained a copy of from the state of California."

But the company says the San Pedro Bay Pipeline wasn't shut down until 6 a.m. Pacific time, about three and a half hours after the PHMSA says it received an alarm.

It's not clear why the company shut the pipeline at 6 am, because according to the company, Houston-based Amplify Energy, they didn't learn of the spill until much later on Saturday morning.

CEO Martyn Willsher said this on Wednesday:

"We were not away of any spill until 8:09 on Saturday morning. I promised you - if we were aware of something on Friday night, I promise you we would have immediately stopped all operations and moved forward."

In response to a reporter's question about the 2:30 a.m. alarm, Willsher said: "We were not aware of any alarm at 2:30."

He also said the company was investigating the timeline and "working with regulators to see if there was anything that should have been noticed."

The spill of 3,000 barrels is relatively small, but it has already impacted wildlife, tarred beaches, and hurt coastal businesses.

It's also raising questions about how, even with preparation, the spill occurred.

The cause of the California spill is under investigation.

Officials are probing whether the rupture may have been caused by a strike from a ship's anchor.

Investigators discovered a section of the pipeline had moved 105 feet and had a 13-inch split running parallel to the pipe.