BISMARCK, N.D. - The Standing Rock Sioux Tribe and other opponents are preparing to argue their case against a proposed expansion of the Dakota Access pipeline.

Texas-based Energy Transfer wants to double the capacity of the line to as much as 1.1 million barrels daily to meet growing demand for oil shipments from North Dakota. The $3.8 billion pipeline has been moving North Dakota oil through to a shipping point in Illinois since 2017.

A hearing is set for Wednesday in Linton, North Dakota, on the proposed expansion.

Opponents have long argued that a leak in the pipeline would threaten the tribe’s Missouri River water supply. The tribe says the proposal to double the line’s capacity magnifies the probability of a disastrous oil spill.