A big oil spill from the Keystone Pipeline in North Dakota last week has hardened opposition to the controversial Keystone XL expansion among landowners along its route, who say they hope to use the incident to help block or stall the project in court.

Operator TC Energy Corp. is in the process of securing land easements for Keystone XL from scores of reluctant landowners in Nebraska, one of the final obstacles to a project linking Canada’s oil fields to U.S. refineries that has been delayed for over a decade by environmental opposition.

The roughly 9,120-barrel spill from the existing Keystone line brings the number of significant releases since the system was built a decade ago to four—much higher than the company estimated in its risk assessments before it was approved—raising worries Keystone XL will be just as problematic.

“The spill confirms what we have been warning people about over the last 10 years,” said Jeanne Crumly, who owns a cattle ranch along Keystone XL’s approved path and fears a spill could contaminate her land and harm her cows.

Brian Jorde, an attorney for the Nebraska landowners, said he expects landowners to file “many appeals to District courts” to oppose TC Energy’s efforts to seize land by eminent domain, the legal provision allowing a government or company to take control of private land for the public good.

Jorde said TC Energy had already begun eminent domain proceedings against 89 families who live along the Keystone XL route since it had secured its permits, and that appraisers were working to determine a “fair value” for the land that would be paid out to owners to finalize the process.

Those assessments can be appealed, he said.

“We are going to take this as far as we can in court and fight as long as we can. We hope a jury will be aware of the recent spills when they decide,” said Diana Steskal, one of the landowners.

Officials for TC Energy did not respond to requests for comment. The company has said its Keystone XL expansion project can be operated safely.

President Donald Trump has been a vocal supporter of the Keystone XL expansion project, saying it will create jobs and improve U.S. energy security. He reversed a decision by former President Barack Obama to deny the project a federal permit on environmental grounds.

The cause of last week’s spill on the existing Keystone line—which runs 2,147-miles from Hardisty, Alberta, to the Texas coast—has yet to be identified.

Prior to that spill, the system released some 9,700 barrels of oil in a South Dakota wetland area in 2017, and around 400 barrels each in incidents in South Dakota in 2016 and North Dakota in 2011.

The incidents underscore that the existing Keystone system has leaked substantially more oil, and more often, in the United States than indicated in risk assessments the company provided to regulators before it was built.

Those risk assessments estimated that a leak of more than 50 barrels would occur “not more than once every seven to 11 years over the entire length of the pipeline in the United States,” according to documents previously reported by Reuters.

Jane Kleeb, president of the Bold Alliance, which has been fighting the Keystone XL expansion proposal for years, said the group may try to challenge TC Energy again before the state Public Service Commission, which had approved the route through Nebraska.

“TC Energy has misled the state and its citizens that their pipelines are safe,” she said.

PSC spokeswoman Deb Collins said the regulatory body had no plans to reopen the issue despite the latest spill. “Our role in the process is complete,” she said.