The Keystone Oil pipeline is back up and running after being shut down last week. TransCanada shut down the pipeline for safety issues.
The pipeline runs from Canada through the Midwest ending at Cushing in Payne County. It brings 500,000 gallons of oil every day to Oklahoma.
TransCanada shut down the 2,100-mile pipeline Wednesday after tests showed possible safety issues.
Company spokesman Shawn Howard said in an email that there were no leaks and "the integrity of the pipeline system is sound."
The system will be operated at a slightly reduced pressure for about 24 hours so additional testing can be completed.
"Once the pipeline system is operating at full pressure, we will be curtailing October volumes and will return to contractual delivery levels in November," Howard said. "We will be having direct discussions with our customers regarding the impact this will have on their deliveries to us."
The potential problems were detected in a section of the line between Missouri and Illinois. The temporary closure isn't expected to affect refinery production or retail gas prices because crude supplies are plentiful across the U.S.