MINNEAPOLIS (AP) — The U.S. Army Corps of Engineers on Monday approved the final federal permit for Enbridge Energy’s planned Line 3 crude oil pipeline replacement across northern Minnesota, bringing the project a step closer to construction.

In a release from its St. Paul office, the Corps said it determined the Line 3 project “is compliant with all federal laws and regulations.” Col. Karl Jansen, commander of the St. Paul District, said the decision followed “an exhaustive review” and extensive work with federal and state regulators, Native American tribes, environmental groups and Enbridge.

“I believe our decision is based on sound science and strikes the balance between protecting natural resources and allowing reasonable development,” Jansen said.

All that remains in the six-year-old process now is for the Minnesota Pollution Control Agency to issue a storm water construction permit to protect surface waters from runoff while it’s being built, and then for the independent Public Utilities Commission to give a final green light. The commission has already approved the project several times.

“These permits are yet another science-based approval for the project moving Line 3 closer to the start of construction,” Enbridge said in a statement. “Final state permits and authorizations are needed for work to begin before the end of 2020.”