A detailed analysis by a pipeline safety expert found the U.S. Army Corps of Engineers underestimated the potential for the Dakota Access pipeline to spill oil into the Missouri River, and called the Corps’ environmental assessment “seriously deficient.”

The review, by a pipeline safety expert hired by the Standing Rock Sioux tribe, called for a rerouting of the pipeline away from areas prone to landslides.

“The Environmental Assessment is incomplete,” said Richard Kuprewicz,  president of Accufacts, Inc., a consulting firm that advises government agencies and industry on pipeline safety and who conducted the review. “I don’t agree with the finding of no significant impacts.”

Kuprewicz was asked by the tribe to provide an outside review of the Army Corp’s final environmental assessment, which had concluded the pipeline would have no significant impact on the environment where it crosses the Missouri river at Lake Oahe and Lake Sakakawea in North Dakota.

That assessment by the Army Corps, the federal agency with jurisdiction over the pipeline project, permitted Dakota Access LLC to proceed with both river crossings. The decision in July was seen as a key in green-lighting the 1,172-mile project that would carry roughly half a million barrels of crude oil per day from the Bakken oil fields of North Dakota to a transfer station in Illinois. (The Environmental Protection Agency had previously urged the Army Corps to revise its environmental assessment out of safety concerns.)

The Standing Rock tribe, whose reservation is a half-mile downstream from the river crossing at Lake Oahe, where  the reservation draws its drinking water, opposes the current pipeline route. Thousands of mostly Native Americans have joined members of the Standing Rock tribe in protesting the pipeline, many calling for it to be shut down entirely.

On Sept 9, the Obama Administration said the Army Corps would withhold granting a final easement for the Oahe river crossing and would conduct an internal review of its environmental assessment.

The election of Donald Trump as president could have a significant future impact on the project. He has not commented specifically about Dakota Access, but has expressed support for fossil fuel infrastructure projects. That includes Keystone XL, which President Obama rejected last year. Trump has said TransCanada should submit a new application for that pipeline when he takes office.

Kuprewicz’s outside review concluded the Army Corps failed to properly evaluate the risk of oil spills where the pipeline crosses the Missouri River at Lake Oahe. He also faults the Army Corps for overstating the ability of leak detection technology to quickly identify oil spills and for underestimating the worst-case scenarios for major leaks.

Kuprewicz’s concern about leaks is based on areas susceptible to landslides.

“If you have a pipeline routed in a landslide area, the only thing [you can do] there is to route it out of the landslide area,” Kuprewicz said.

Army Corps spokesperson Moira Kelley said the Army Corps is reviewing Kuprewicz’s report and exploring a range of options. President Obama said last week that the Army Corps was considering rerouting the pipeline.

Energy Transfer Partners, the parent company of Dakota Access LLC, defended the Army Corps’ initial assessment, which was prepared by Dakota Access LLC and approved by the Army Corps.

“We are confident the USACE [US Army Corps of Engineers] has adequately addressed the portion of the project subject to their review,” Energy Transfer Partners spokesperson Vicki Granado said in a statement, “They are the experts in this area and we believe they have done an excellent job addressing any comments received to date.”

A key distinction may be whether the landslide prone area falls under the scope of the Army Corps’ environmental assessment, which looked only at federal property, an area covering the Missouri River and immediately adjacent lands. Kuprewicz said that a landslide near the Missouri, but off federal property, could still cause oil to leak into the river and therefore should be subject to Army Corps review.

Recent court rulings, however, suggest the Army Corps does not need to assess the pipeline beyond federal property.

“The decisions by two separate federal courts show that the U.S. Army Corps of Engineers acted with great care and followed the law with respect to the river crossing permits issued to Dakota Access,” Granado said.

Dakota Access is now mobilizing equipment to the drill under Lake Oahe and “remains confident” that it will receive the required easement for its proposed route “in a time frame that will not result in any significant delay in proceeding with drilling activities,” the company said in a statement.

Mohammad Najafi, a pipeline construction safety expert at the University of Texas at Arlington, who did not take part in the Army Corps assessment or Kuprewicz’s review, said a landslide falling on top of the pipeline would cause it to rupture and leak.  

“The pipe is not designed for that load,” Najafi said. “There will be a lot of weight on the pipe, that would cause the pipe to break, that’s obvious.”

Najafi said rerouting the pipeline away from landslide prone areas would be the best solution. He added, however, that increasing the wall thickness of the pipe or encasing it in concrete might suffice if rerouting the largely completed pipeline is prohibitively expensive.

Kuprewicz found fault with claims in the Army Corps’ assessment that remote sensors could detect major leaks and the pipeline could be shut down within minutes.

“I’ve been in too many investigations now where they’ve claimed they are going to shut the line down in less than 10 minutes and it’s [actually] 3 hours later,” Kuprewicz said. “You are overstating the technical ability of the equipment to do its job.”

Najafi agreed.

“They get a lot of false alarms with this type of equipment and the operators don’t know which ones are right and which ones are wrong,” he said. “By the time action can be taken, millions of gallons of oil can be spilled.”

A number of groups including the Standing Rock tribe and the Interior Department have called on the Army Corps to prepare a more thorough environmental impact statement. Kuprewicz said the quality of the research is more important than the name.

“You can do an EIS [environmental impact statement] that takes longer, but if you don’t do that adequately, that is just an illusion as well,” he said.