Federal pipeline safety officials on Tuesday issued a corrective action order to ExxonMobil Pipeline Co. after one of its pipelines ruptured last week in central Arkansas.
The order from the Pipeline and Hazardous Materials Safety Administration comes after ExxonMobil's Pegasus pipeline ruptured Friday in the small city of Mayflower, about 25 miles northwest of Little Rock.
The order prevents ExxonMobil from restarting operations on the failed segment of the pipeline until the agency is satisfied with repairs and is confident that all immediate safety concerns have been addressed.
Investigators are still working to figure out what caused the pipeline to rupture, but the corrective action order says ExxonMobil reversed the system flow of the pipeline in 2006.
"A change in direction of flow can affect the hydraulic and stress demands on the pipeline," the order, dated Tuesday, says.
About 3,500 to 5,000 barrels of crude oil spilled after the pipeline ruptured, according to ExxonMobil estimates cited in the corrective action order. That oil spewed onto lawns and roadways and almost fouled nearby Lake Conway. No one was hurt, but the spill led authorities to evacuate more than 20 homes.
The pipeline, which runs from Patoka, Ill., to the Texas Gulf Coast, was originally built in 1947 and 1948, according to federal pipeline safety officials. It remains out of service for now. In order for that to change, ExxonMobil would need written approval from a federal pipeline safety official, according to the corrective action order.
ExxonMobil also has to submit a restart plan, complete testing and analysis about why the pipeline failed and jump through a number of other hoops under the order.
The order signed by Jeffrey Wiese, associate administrator for pipeline safety, says "continued operation of the Pegasus Pipeline would be hazardous to life, property, and the environment."
The federal agency's order comes as Arkansas' attorney general promised a state investigation into the cause and impact of the spill and other officials say they plan to ask Exxon to move the Pegasus pipeline to protect drinking water.
"There are many questions and concerns remaining as to the long-term impacts, environmental or otherwise, from this spill," Arkansas Attorney General Dustin McDaniel wrote to ExxonMobil executives Tuesday. He also asked ExxonMobil to preserve records pending his investigation.
The company said it will cooperate with McDaniel's office. ExxonMobil spokesman Alan T. Jeffers said Tuesday evening that the company is reviewing the corrective action order, but declined to comment further.
Jeffers also said the company had no comment after a Central Arkansas Water official said the water system plans to formally request that ExxonMobil relocate the Pegasus pipeline outside the area that drains into the main source of drinking water for hundreds of thousands of customers in the region.
"We've been concerned about the presence of the pipeline in the (Lake Maumelle) Watershed for some time now," said John Tynan, Central Arkansas Water's watershed protection manager. "We've taken a number of steps to mitigate the risks that it poses, but obviously the only way to eliminate all risk is to remove the pipeline from the watershed."