NEAR TIOGA, N.D. — Steve Jensen remembers the land just north of his home looking like the surface of the moon last fall.
Crews dug a massive hole in the wheat field where a pipeline spewed 20,600 barrels of oil by the time he discovered it while harvesting in September 2013. It remains the largest such incident in the state's history.
But the cleanup crews have been gone for months and the land has started to green again thanks to a cover crop planted last fall.
"It's five and a half years. It's a long time," said Steve's wife, Patty. "But it does feel really good to see it growing something."
The couple expect plenty of work ahead in restoring the land. They installed some windbreaks to prevent erosion and accumulate moisture over the winter, and the rye and slender wheatgrass they planted on the site have "come up really nice," Patty said.
"We're just trying to build the soil back up," she said. "We're trying to figure out what it can do."
The cleanup site totaled about 75 acres, Patty said, as crews used a process to heat the hydrocarbons out of the contaminated soil. Pipeline owner Andeavor reported in 2017 that the estimated remediation costs stood at $93 million, dwarfing previous expectations. The state fined the company $454,000 for the spill, which was blamed on a lightning strike.
Tom DeSutter, a North Dakota State University professor and soil scientist who's part of a team hired by the pipeline company, said restoring the land isn't a matter of simply putting the soil back in the ground. Planting will help prevent erosion and produce organic matter, he said, and precipitation will also play an important role.
"If you take a bucket of soil from your backyard and you grind it up, smash it up and then lay it back down again, that's not going to be as productive as the soil next to it," DeSutter said.
The university has plots nearby to test how plants grow on remediated soil, and DeSutter said they plan to work with the Jensens for a few more years.
Bill Suess, spill investigation program manager for the state Department of Environmental Quality, said the spill hit an isolated layer of water but didn't affect a drinking water aquifer deep underground. The pipeline company has water monitoring wells installed around the site, he said.
Suess said the incident prompted the department to be more proactive about notifying other state agencies and the public about spills. The Associated Press reported at the time that health officials didn't publicly announce the incident for 11 days.
"Unfortunately, the governor's office found out about it through the media, which is not a good thing," Suess said.
Ron Ness, president of the North Dakota Petroleum Council, said the industry has focused on monitoring and leak detection systems in the years after the Tioga spill. He pointed to the Intelligent Pipeline Integrity Program, or iPIPE, at the University of North Dakota's Energy and Environmental Research Center, which aims to develop leak detection technology.
The university said the program formed in response to a challenge from Gov. Doug Burgum, who in 2017 gathered oil and gas company officials behind closed doors to discuss spill prevention. In a statement at the time, he pushed for "continuous improvement" rather than further regulations. The Republican governor chairs the Industrial Commission, which oversees the industry.
Still, Suess said state officials collected more than 700 reports of spills involving pipelines of all types in North Dakota between 2014 and 2018, though annual figures have declined in recent years.
"It's almost that spills have become a matter of course, it's just part of the whole business," said Wayde Schafer, conservation organizer for the Dacotah Chapter of the Sierra Club.
Patty Jensen said the pipeline company, which was known as Tesoro Logistics at the time of the spill, "has been pretty decent to us." She said they grew attached to the workers who cleaned up the site, a couple of whom recently wished her a happy Mother's Day.
Still, Jensen said the spill affected their lives in this rural stretch of northwest North Dakota. She quit her job as an office manager in Stanley, as she had to deal with crews on their land, state health officials and news reporters.
But Jensen said she and her husband "stayed on top of it" because "it needed to be done right." She said the experience led her to what she sees as regulatory shortcomings and helped her understand the "huge" impact spills can have on land and water.
"It makes you realize how precious it is," Jensen said.