Sen. Bernie Sanders is trying to block a controversial oil pipeline from being constructed in North and South Dakota by adding an amendment to an otherwise popular infrastructure bill.

The Vermont independent introduced an amendment to the Water Resources Development Act of 2016 that would keep the secretary of the Army from allowing the Army Corps of Engineers to grant an easement so the Dakota Access Pipeline can cross Lake Oahe. The lake is a reservoir that spans the Dakotas.

The former Democratic presidential candidate's amendment would prevent the pipeline from crossing the lake until an environmental impact statement on the crossing can be done.

The Water Resources Development Act is a $9 billion bill that would fund 25 Army Corps of Engineers projects that have already been authorized and would spend billions on upgrading the country's drinking water infrastructure. It has strong bipartisan support, and a procedural vote is scheduled on the bill next week.

Sanders is a noted supporter of efforts to stop the pipeline, which include a protest that has caused construction of the pipeline to stall in North Dakota. Native American tribes in the area working to stop it say the pipeline crosses over sacred land. They also are concerned that the pipeline, carrying crude oil, would contaminate the Missouri River if it leaks where it is planned to cross under it.

Sanders' opposition is based in the effort to keep fossil fuels in the ground. A judge is expected to rule Friday on whether to grant an injunction that would stop work on the pipeline near an area the tribes say is sacred.

"Like the Keystone XL pipeline, which I opposed since day one, the Dakota Access fracked oil pipeline will transport some of the dirtiest fuel on the planet," Sanders said last month.

"Regardless of the court's decision, the Dakota Access pipeline must be stopped. As a nation, our job is to break our addiction to fossil fuels, not increase our dependence on oil. I join with the Standing Rock Sioux Tribe and the many tribal nations fighting this dangerous pipeline."

Sanders is scheduled to speak at a Tuesday rally in Washington to lobby President Obama to put a halt to the pipeline's construction.