CANTON, S.D. — Commissioners in a South Dakota county on Tuesday approved a conditional use permit for a pumping station needed for an expansion of the Dakota Access Pipeline.

The Lincoln County Board voted 4-1 in favor of the proposal. The station, expected to cost between $30 million and $40 million, would be built near Harrisburg in southeastern South Dakota.

Texas-based Energy Transfer announced in June it plans to expand the pipeline's capacity from more than 500,000 barrels per day to as much as 1.1 million barrels. The pipeline has been moving North Dakota oil through South Dakota and Iowa to a shipping point in Illinois since June 2017.

The company also needs additional stations in North Dakota and Illinois.

The Lincoln County Planning Commission approved the project last month. But members of Dakota Rural Action, a South Dakota environmental group, appealed the decision to the county board.

Opponents warned of possible pollution, the Argus Leader reported.

Senior organizer Rebecca Terk of Dakota Rural Action told commissioners that the pumping station would increase risks of the pipeline developing leaks or a catastrophic blowout. She said that in turn would harm water supplies and farmland.

"It's not just about the pipe as a whole," Terk said. "It's about those imperfections that exist throughout the pipeline."

Supporters testified in favor of the project, including union representatives and Chris Studer, who represented the East River Electric Cooperative, which would sell electricity for the five pumps that would be at the facility.

Chuck Frey, a vice president of engineering for Energy Transfer, told commissioners the facility had been designed with a number of safeguards.

The site includes a 13,000-gallon tank to provide surge relief, automatic sensors that shut the facility down in case of fire, and sensors that monitor for leaks.

Commissioner David Gillespie cast the lone "no" vote. Gillespie questioned whether there would be enough security at the building to prevent someone from damaging it.

Last month, an administrative law allowed the Standing Rock Sioux Tribe to intervene on plans to expand the Dakota Access pipeline. North Dakota regulators have set a Nov. 13 public hearing in Linton, near where the pump station would go, on the proposed expansion.

The tribe led original opposition to the crude oil pipeline. The $3.8 billion pipeline is less than a half-mile from the Standing Rock Reservation, beneath a Missouri River reservoir that is the tribe's water source.

Fears of an oil spill into the river sparked massive protests in 2016 and 2017, drawing thousands of pipeline opponents to North Dakota. Energy Transfer says the line is safe.

Energy Transfer says the expansion would help meet the growing demand for oil from North Dakota, the nation's second-biggest oil producer behind Texas. The company needs permission from the North Dakota Public Service Commission for the expansion because some of the land needed is outside of the pipeline's path.