By Tony Barboza and Javier Panzar, Los Angeles Times (TNS)

LOS ANGELES — Three U.S. senators are raising concerns about a Texas-based company’s “insufficient” response to a pipeline failure last week that released thousands of gallons of crude into the ocean and fouled the Santa Barbara County coastline.

In a letter Thursday to the Pipeline and Hazardous Materials Safety Administration, Sens. Barbara Boxer (D-CA), Dianne Feinstein, (D-CA), and Edward J. Markey (D-MA) questioned whether Plains All American Pipeline acted quickly enough in detecting and reporting the May 19 spill from its oil line near Refugio State Beach.

“We need answers about why this happened, why the response was insufficient and what can be done to prevent another tragic spill like this from happening in the future,” the senators wrote.

Plains Pipeline employees detected “anomalies” in the 11-mile pipeline at 11:30 a.m., and confirmed the failure on-site at 1:30 p.m. They reported the spill to the National Response Center just before 3 p.m., according to the letter.

“Based on this timeline, we are concerned that Plains Pipeline may not have detected this spill or reported it to federal officials as quickly as possible, and that these delays could have exacerbated the extent of the damage to the environment,” the senators wrote. They asked why it took two hours for Plains Pipeline to visually confirm the existence of a release of oil.

The letter also expressed concern that the ruptured pipeline lacked an automatic shutoff valve that could have detected a loss in pressure and decreased the amount of oil released.

Among other requests, the senators asked for detailed information on the company’s oil spill response plans, the timeline of its response and the line’s inspection history. They also want to know whether federal regulators have legal authority to require the company to install automatic or remote shutoff valves on the line as it is repaired.

At a news conference before the letter was released, Plains Pipeline officials apologized for the spill.

“We will not leave until the job is completed,” said Patrick Hodgins, senior director of safety and security with the company.

The lawmakers’ letter came as federal regulators announced that Plains Pipeline employees had removed the failed section of pipeline for testing following an excavation that took several days.

The section of pipe — about 50 feet in length, according to the company — will be taken to an independent metallurgical laboratory in Ohio.

The pipeline released up to 101,000 gallons of crude, with an estimated 21,000 gallons of oil flowing downhill from the spill site through a culvert, under U.S. 101 and into the Pacific.

The pipeline, known as Line 901, transports crude oil from Las Flores to Gaviota and then to refineries throughout Southern California. It remains shut down while federal pipeline regulators investigate the cause of the failure, both on-site and at the company’s control room in Texas.

The spill has closed several miles of beaches on the Gaviota Coast while nearly 1,000 cleanup workers try to remove oil from the rocks, sand and the ocean surface.

On Wednesday, the U.S. Environmental Protection Agency and U.S. Coast Guard ordered Plains Pipeline to clean up the area under requirements of the federal Clean Water Act.

The senators, in their letter Thursday, also criticized the cleanup efforts, writing that authorities may not have “fully utilized” trained responders from local agencies and delayed training for volunteers.

“We are concerned that insufficient preparation may have slowed down the response effort,” the senators wrote.

(c)2015 Los Angeles Times. Distributed by Tribune Content Agency, LLC.

Photo: A large glob of oil on the beach at Arroyo Quemado on Friday, May 22, 2015, after the oil spill off Refugio State Beach in Santa Barbara County, Calif. (Brian van der Brug/Los Angeles Times/TNS)