Oregon regulators have approved an expansion of a crude oil train terminal near Clatskanie to move 1.8 billion gallons of oil annually, enough to bring 50 oil trains per month through Portland and small towns along the Columbia River.

The Oregonian reports the state's Department of Environmental Quality approved an air pollution permit for Global Partners' oil train terminal on Tuesday. The terminal unloads North Dakota oil from trains onto barges, which then head to refineries in Washington and California.

Earlier this year, the agency fined Global Partners $117,292 because the terminal moved 300 million gallons of oil last year, surpassing its permitted amount of 50 million gallons.

Global Partners has been unloading crude oil in Clatskanie since 2012. The company says it also plans ethanol production.