Completion of the Dakota Access oil pipeline seemed almost inevitable. But then the Obama administration stepped in this month and offered a respite to the medley of Native Americans, environmentalists and Midwestern landowners who oppose it.

Three federal departments announced that work would stop on a pivotal section of the 1,172-mile pipeline in North Dakota while they second-guessed how the Army Corps of Engineers approved most of the project in July. The move was applauded by critics, who say the pipeline could pollute drinking water from the Missouri River and destroy land that’s culturally important to Native Americans. Many also object to the energy company acquiring land from family farmers in Iowa via eminent domain.

The controversy stems from a series of government decisions since 2014, when Energy Transfer Partners announced a plan to carry 570,000 barrels of crude per day from the Bakken oil fields in North Dakota to existing infrastructure in Illinois. A look now at those choices explains why thousands demonstrated against the pipeline and dozens were arrested near the Standing Rock Sioux’s reservation and in Iowa in the summer.

“They’ve been using backdoor process to get the pipeline approved,” said Dallas Goldtooth, an activist with the Indigenous Environmental Network. “The antiquated permitting process was not designed for mega fossil fuels projects.”

New pipeline opponents emerged this week, when archaeologists from the Smithsonian, Chicago’s Filed Museum and other institutions wrote a letter to President Barack Obama this week. The letter criticized the Energy Transfer Partners’ “recent destruction” of Sioux burial grounds.

But construction rushes ahead, apart from a section near an encampment of hundreds of Native American protesters. It stands at 60 percent complete, according to a memo from Energy Transfer Partners CEO Kelcy Warren to employees this month.

Critics say the following moves explain why the pipeline looks to them like an environmental hazard and a government boondoggle.

Energy Transfer Partners The Dakota Access Pipeline would stretch 1172 miles, from North Dakota oil fields to an existing Illinois pipeline.

Oil Spills, Climate Change Concerns

Critics say that the U.S. Army Corps of Engineers used a lenient environmental review that didn’t adequately examine the potential for oil spills or the impact on climate change.

Getting the federal agency’s approval was essential because the pipeline would cross its rivers and waterways 202 times.

The Army Corps granted permission to an environmental assessment relied on skewed data from Energy Transfer Partners, according to attorney Carolyn Raffensperger. The assessment made alternatives to the pipeline, such as using railroads to move the oil, which sound costlier and it came to other conclusions that underestimated the environmental risks, said Raffensperger.

Pipeline spills happen nearly every day in the U.S., federal data shows. The environmental assessment didn’t address what damage a Dakota Access leak could cause, Raffensperger said.

“The approval process for pipelines is fatally flawed,” said Raffensperger, who’s litigating against the pipeline’s use of eminent domain in Iowa.

Critics argue the pipeline should have been vetted through a more rigorous environmental impact statement. The Army Corps says on its website that option would only be available if the environmental assessment had turned up anything troubling.

“The [agency] drafted an Environmental Assessment) to determine if the placement and operation and maintenance of the pipeline on federal real property interests have potential to cause significant environmental effects,” it states. “If there is such potential, the [Army Corps] will prepare an Environmental Impact Statement.”

The Army Corps has shown some concern for negative consequences if hazardous materials were to get loose elsewhere.

It rejected an earlier route that would cut across the Missouri River upstream from Bismarck, North Dakota, partly to avoid the risk of contaminating the state capital’s water source. But it was remapped downstream to the present contested crossing, where the Standing Rock Sioux says they’ll be the ones who suffer in the event of a spill.

“We have designed the state-of-the-art Dakota Access pipeline as a safer and more efficient method of transporting crude oil than the alternatives being used today, namely rail and truck,” said Energy Transfer Partners CEO Kelcy Warren in a memo to employees last week that the company released to the press.

‘Loophole’ Speeds Up Project

Out of all the local, state and federal agencies with some jurisdiction over the project, the U.S. Army Corps of Engineers had the most influential input, although only 37 miles of pipeline would exist inside its territory. Its approval came last in the review process.

Sierra Club lawyer Doug Hayes said the Army Corps exploited “a loophole” opened by Obama’s energy priorities to push the pipeline through the review process. Hayes is litigating against the use of eminent domain to seize property from land owners along the pipeline’s route in Iowa.

The U.S. Army Corps of Engineers subjected the pipeline to what’s called the Nationwide Permit 12 process and narrowly looked at “several hundred” waterways crossing essentially as independent projects, rather than judging it as one, massive structure, Hayes said. This permit program was designed for small structures like boat ramps and mooring buoys that affect fewer than half an acre of the Corps’ jurisdiction.

“As far as we can tell, it was only used for truly minor pipeline projects” until Obama called for the expedited approval of the Keystone XL pipeline in 2012, he said.

The project should have been subjected to what’s known as a 404 permit, a part of the Clean Water Act that considers the impact from projects like airports, dams and mining exploration, according to Hayes and other opponents.

The Army Corps declined to answer The Huffington Post’s queries about the pipeline because of ongoing litigation, but material on its website said the agency could only evaluate the sections on its land, rather than the pipeline in its entirety.

“For this project, [the Army Corps] has jurisdiction over a very small portion of the overall pipeline and may not regulate where it does not have jurisdiction,” the site post states.

ROBYN BECK via Getty Images The Standing Rock Sioux tribe has accused Energy Transfer Partners of deliberately destroying important artifacts, including graves shortly after historical sites were identified.

3 Federal Agencies Called Out The Army Corps

Long before the protesters garnered the support of celebrities including Leonardo DiCaprio and Pharrell Williams, three government offices expressed dismay at the Army Corps’ decision making.

The Environmental Protection Agency, the Department of the Interior and the Advisory Council on Historic Preservation in March wrote separate letters raising the possibility of water contamination and destruction of historic sites in terms echoing the Standing Rock Sioux, The Associated Press reported in April.

They were concerned that tribes along the route had not been properly consulted and called on the Army Corps to go ahead with a formal environmental impact statement.

Those fears were realized earlier in September, according to the Standing Rock Sioux, who accused the company of deliberately destroying important artifacts, including graves shortly after the historical sites were identified.

Protesters entered the company’s land in response, where security guards reportedly used pepper spray and dogs to disperse them.

“They went out of their way to desecrate this land,” said Allison Renville, who was at the protest camp that day and grew up on the Sisseton Wahpeton Oyate reservation in South Dakota. “People were really upset. We were kind of shocked that it was even happening.”

Energy Transfer Partners insists that it is culturally sensitive to what might be underground and has denied encountering anything significant. The company has also claimed that protesters have attacked its workers, though spokeswoman Vicki Granado refused to provide specifics of any alleged altercation “for security reasons.”

The company’s chief executive wrote in a memo that multiple archaeological studies “found no sacred items along the route.” Environmental worries are likewise overhyped too, he wrote, as other pipelines crisscross the region. There are 25 crude oil and natural gas pipelines in North Dakota, according to the state’s pipeline authority.

Farmers’ Land Taken for Pipeline

In Iowa, protesters have fumed over the state’s use of eminent domain to force landowners to sell land that Energy Transfer Partners needs to build the pipeline. Police arrested more than 40 demonstrators for alleged trespassing at a construction site on Sept. 17.

Farmland cannot be seized through eminent domain in the state, attorneys said, unless it’s for a project with a public benefit like a highway or sewer line. Despite opposition, the Iowa Utilities Board in March determined that “the proposed pipeline will promote the public convenience and necessity.”

Among the roughly two dozen property owners at the time fighting the eminent domain order were a man trying to preserve land in his family since 1898, a family of turkey farmers and a woman who grows crops like blueberries, rhubarb and asparagus.

“We do not think there’s any public benefit from this at all,” said Kari Carney, executive director of 1000 Friends of Iowa. “The process was really sort of rammed through.”

Energy Transfer Partners claims that the pipeline will annually generate $129 million in property and income taxes.

As a financial precaution, the Iowa Utilities Board said its approval was contingent on the pipeline’s parent companies, which also includes Sunoco Logistics and Phillips 66, to put up money in the event the pipeline causes an emergency in Iowa.

An Iowa Utilities Board spokesman declined to comment due to ongoing litigation.

The next steps

Though the Obama administration froze work on one section of the project near the Standing Rock Sioux, construction continues elsewhere as much of the route is on private land.

Other tribes have joined the Standing Rock Sioux, who have a lawsuit pending against the Army Corps over the approval process. Some Iowa landowners have sued the state for its use of eminent domain.

The wildcard may be what decision the Obama administration reaches. Though the president was earlier a proponent of the Keystone XL pipeline, he rejected it last year. The statement the Department of Justice, the Army and the Department of Interior issued last week announcing work would not proceed near the tribe raised the question of whether the administration has undergone a transformation on projects like this.

“This case has highlighted the need for a serious discussion on whether there should be nationwide reform with respect to considering tribes’ views on these types of infrastructure projects,” the joint statement said.

If the pipeline comes to fruition, Energy Transfer Partners stands to reap huge benefits as other companies have abandoned plans for competing pipelines in the area.

“We got so lucky,” CEO Kelcy Warren told Bloomberg last year. “All of our competition vaporized.”