Federal pipeline regulators on Monday approved the restart of a section of Exxonmobil Pipeline Company’s Pegasus pipeline that runs through Texas.

The section, referred to as the southern segment, does not include Arkansas or Mayflower, where the pipeline ruptured and spilled several thousands of barrels of heavy crude and industry diluents almost exactly one year ago.

The Pipeline and Hazardous Materials Safety Administration published a certified letter to Exxon dated March 31 on Monday granting the company’s request to restart the segment of pipe submitted Jan. 31 of this year.

The company asked that the southern segment, 210 miles stretching from Corsicana, Texas to Nederland, Texas, be restarted at a reduced pressure.

Exxon spokesman Aaron Stryk said Monday the company will operate the section of the pipeline at no more than 80 percent of the documented pressure at the time of the failure in Mayflower, pursuant to the corrective action order issued by PHMSA following the spill.

A remedial work plan for the northern segment of the Pegasus pipeline, the segment that includes Faulkner County, Mayflower and the Lake Maumelle Watershed, was submitted to PHMSA by Exxon over the weekend, Stryk said.

The one year anniversary of the spill was Saturday, March 29.

Before Exxon would be allowed to restart the northern section that includes Arkansas, the company must provide and get approval on a plan that includes verification of the pipeline’s integrity, according to PHMSA’s corrective action order.

Stryk said Exxon’s remedial work plan includes "multiple layers of integrity verification measures," such as field inspections, excavations and hydrostatic testing, "which have been developed following a detailed investigation and analysis into the cause of the (oil spill in Mayflower)."

The tests in the remedial work plan, once approved, would take more than one year to complete, and the pipeline would not be started in Arkansas before that time, Stryk said.

Stryk did not have a timeline for the restart of the southern or Texas segment of the pipe, but said, "We will restart the Texas segment once all necessary safety and operational steps have been completed."

The Texas segment will be used by Exxon to take product between storage at Corsicana and refineries near Nederland and Beaumont.

The entire Pegasus pipeline is 850 miles in length and transports crude from Patoka, Illinois to Nederland, Texas.

The failed pipeline uses ERW seam pipe, which was documented in as early as 1989 by a U.S. Department of Commerce and National Institute of Standards and Technology report to be "inherently susceptible to seam failures."

Exxon also says the "root cause" of the failure was original manufacturing defects in the "low-frequency electric resistance weld seam."

A metallurgical study submitted to PHMSA and commissioned by Exxon states the failure resulted due to the "reduction of the wall thickness" in the ERW seam caused by the presence of manufacturing defects.

The Clinton School of Public Service hosted a one-year anniversary panel discussion on the Mayflower oil spill Monday, where speakers were to focus on lessons learned and provide input on how to minimize the chance of another disaster in the future.

Panelists like Graham Rich, CEO of Central Arkansas Water, and Representative Tim Griffin said they would advocate for the pipeline’s retirement or relocation away from the Lake Maumelle watershed, a fresh water source for more than 400,000 in the state.

About nine miles of the 210 of the southern segment of the Pegasus pipeline are ERW pipe, according to Exxon.

(Staff writer Courtney Spradlin can be reached by email at courtney.spradlin@thecabin.net or by phone at 505-1236, or on Twitter @Courtneyism. To comment on this and other stories in the Log Cabin, log on to www.thecabin.net. Send us your news at www.thecabin.net/submit)