The Standing Rock Sioux Tribe has threatened to sue the Army Corps of Engineers over the $1,9 billion project, after it was granted final approval in September.
The tribe has been seeking $3.8 billion to repair the pipeline.
The Army Corps is now expected to give its final approval for the project in February.
In a letter to the tribal council, the Corps said that it is “unable to address the environmental impact on the Standing Rock reservation and other federally-owned lands.”
A decision by the Army on the project will depend on a recommendation from the Department of the Interior’s Bureau of Reclamation.
The Standing River Sioux Tribe said it was “not satisfied with the Bureau’s assessment” and filed suit in federal court in North Dakota.
The tribal council also filed a lawsuit against the Army.
The Corps is the lead agency for the Dakota Access Pipeline, and the Army has a legal responsibility to protect tribal lands.
In November, the Army said that the tribe’s request was “invalid.”
“The Standing Rock Tribe is entitled to access to and use of its land and resources and the lands and resources of the Bureau of Indian Affairs,” the Army wrote.
“The Tribe is not entitled to a pipeline project that would disrupt its access to these lands.”
The Corps also said that a decision to approve the pipeline “will be made based on the facts and circumstances in the application, including the fact that the Tribe is a federally-recognized tribe.”
The Army said the decision was not related to the tribe, but to the Standing Sioux tribe.
The tribes land and water has been under threat for decades.
In 2014, a court ordered the Army to stop pumping water into a river in the reservation to clear land for construction of a dam on Lake Oahe.
The pipeline company said it did not believe the river was a dam, and that the Army was “unaware of the Tribe’s position.”
A lawsuit by the tribe and the tribe members against the Corps, along with the state of North Dakota, the Department in the state, the Standing Water Sioux Tribe and other groups has been pending since November.
The lawsuit seeks an injunction to block the pipeline and the Corps from continuing with its plans.
“We are disappointed that the Corps has taken this step that has jeopardized our rights and the Tribe will not be able to receive its $3,000 permit,” the tribe wrote.
The Morton County Sheriff’s Department said that they are investigating the matter.
A report from the Standing Waters Tribal Council says that the tribes attorneys filed the lawsuit after the Army denied the tribe the necessary permits.
“While the Corps is not responsible for any adverse environmental impacts caused by the project, the tribe is not required to disclose the environmental effects of the project to the public,” the report says.
The report says that after the Corps approved the pipeline in October, the Bureau also refused to provide tribal officials with additional information about the pipeline project.
The company behind the pipeline, Energy Transfer Partners, said in a statement that they “will cooperate with any legal process that is requested.”