CHEYENNE, Wyo. — A pipeline company plans to replace portions of a northeast Wyoming natural gas pipeline that has had two recent leaks, including one that shut down a highway for more than two hours, though what caused the problems might not become publicly known.
None of the government agencies that oversee oil and gas pipelines — the U.S. Pipeline and Hazardous Materials Safety Administration, Wyoming Public Service Commission or Wyoming Oil and Gas Conservation Commission — has been following up on what happened because they lack jurisdiction over the 60-mile stretch where the leaks occurred.
The 16-inch pipeline is too far removed from where the natural gas came out of the ground for the Wyoming Oil and Gas Conservation Commission to have oversight. PHMSA only regulates pipelines that cross state lines.
The section of pipeline isn’t under Wyoming Public Service Commission purview because it is upstream of a gas-processing plant and not close to a populated area, commission attorney Chris Petrie said Wednesday.
“If it went through a cluster of houses or other structures meant for human occupation, then it would be,” Petrie said.
The much bigger of the two leaks happened 14 miles north of Douglas on Sept. 6 and prompted law enforcement to shut down Wyoming Highway 59 for more than two hours while workers shut off the flow. The leaking natural gas didn’t ignite, but could have.
Operating at about two-thirds capacity, the buried pipeline was carrying 40 million cubic feet of gas per day to the Tallgrass natural gas processing plant outside Douglas, said Rosslyn Elliott, spokeswoman for Denver-based DCP Midstream.
“It was pretty quickly restored,” Elliott said. “It wasn’t out of service for very long.”
On Aug. 30, an inspection with a device called a smart pig that detects leaks, dents and other problems as it travels through a pipeline found a pinhole leak about 40 miles to the north, in Campbell County, Elliott said by email.
The company is still investigating the leaks and has been planning to replace portions of the pipeline based on previous inspections, she said.
DCP Midstream isn’t required to release its investigation to the public.
The company did notify the Wyoming Department of Environmental Quality of the leaks because they caused air pollution. The Sept. 6 leak vented gas for 3 ½ hours and likely discharged more than 5 tons of volatile organic compounds, according to written notification the company provided to the department.
The Department of Environmental Quality isn’t among the agencies in charge of pipeline safety.
PHMSA in March proposed new regulations to expand its inspection and repair rules to include lines in some rural areas and those near oil and gas fields. PHMSA spokespeople declined to comment on the record, saying the pipeline was outside their jurisdiction.
Northeast Wyoming is a major gas-producing area but the DCP Midstream pipeline leaked well downstream of any gas fields. The Wyoming Oil and Gas Conservation Commission only regulates in-field flowlines and gathering systems, according to spokeswoman Kimberly Mazza.
“Once the oil or gas reaches the sales point and custody of the oil or gas transfers from the oil and gas operator to someone else we typically no longer have authority,” Mazza said by email.