A Minnesota state senator is accusing Enbridge of withholding data on drilling fluid used during construction of the Line 3 oil pipeline.
DFL Sen. John Marty of Roseville exchanged letters with Enbridge officials last month over his request for details about the fluid used by contractors installing the 340-mile replacement pipeline along a new route across northern Minnesota last year.
Drilling fluid, also known as drilling mud, is used as a lubricant during the horizontal directional drilling process, when crews bore a tunnel underneath a river or wetland, then pull the pipe through. The fluid is primarily made up of bentonite clay, water and additives and is not considered toxic, but can harm aquatic life.
The Minnesota Pollution Control Agency has said that 28 accidental releases of drilling fluid — commonly known as frac-outs — occurred at a dozen river crossing locations between early June and early August 2021.
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Those included 13 releases into wetlands and one into a river, when 80 to 100 gallons spilled into the Willow River in Aitkin County on July 6. The MPCA has said those releases are under investigation as potential violations of Line 3’s water permit.
In a Jan. 7 letter to Enbridge, Marty said experts have told him that contractors tightly control the amount of drilling mud needed for each crossing. But the MPCA has only received data showing how much fluid was cleaned up at the frac-out sites, Marty wrote, which “doesn’t show much was pumped into the ground or released into our waters in the first place.”
He called it “inexcusable” that the MPCA can’t get access to the information.
“They should not need to turn to people outside of the agency for help in obtaining the data,” Marty wrote.
In an interview last week, Marty said the data he’s requesting — including the total amount of drilling mud used and recovered at each crossing — would give a clearer picture of potential environmental impact from the frac-outs, and whether there were more than the 28 sites reported.
“It would show us where the spills were, where the contamination is, where it's risking the groundwater.” he said.
In a Jan. 14 response to Marty, Bobby Hahn, Enbridge’s technical manager of environmental projects, wrote that the inadvertent release of drilling fluid is “a generally known and common risk” associated with horizontal directional drilling, the crossing method that’s considered the least disruptive to water bodies.
Enbridge followed plans approved by the MPCA for each crossing to minimize the effects of a release, Hahn wrote. He said Enbridge and its contractors “carefully monitored” all aspects of the crossings, but the project’s permits did not require the company to maintain or report the specific data that Marty is requesting.
Marty called Enbridge’s response letter “dismissive.”
“They basically said, ‘We don't have to, and we don't need to, and we don't even need to keep this stuff,” he said. “Which struck me as kind of a backhanded way of saying, ‘We could destroy the data. We could cover it all up.’”
On Jan. 21, Marty wrote to Minnesota Attorney General Keith Ellison and MPCA Commissioner Katrina Kessler, asking them to force Enbridge to disclose the data by halting operation of the pipeline. Line 3 was completed last fall and started pumping oil on Oct. 1.
In a statement, Enbridge spokesperson Juli Kellner said that during the permitting process, Enbridge “clearly communicated” the potential for inadvertent releases of drilling mud, which it sought to avoid.
When the releases occurred, Enbridge immediately followed plans for containing and cleaning up the sites, supervised by independent environmental monitors, Kellner stated.
MPCA spokesperson Darin Broton said the agency understands Marty’s frustration, but is following state law, which limits how much information can be disclosed during an active investigation.
“More specific information about the frac-outs will be released once we have concluded the investigation, which includes finalizing penalties against Enbridge,” Broton stated.
At Marty’s request, MPCA officials have met with outside environmental experts to better understand their concerns about ongoing contamination from drilling mud, Broton said. He said the compounds in the mud were thoroughly reviewed during the Line 3 permitting process.
Marty said during the permitting process, Enbridge misrepresented the risk of frac-outs as low.
“Now they're pretending like, ‘Nothing's wrong. We took care of it. It's done,’” he said. “To me, that's something that's absolutely outrageous. And I'm hoping that the agency and attorney general's office can follow up and hold them accountable.”