BISMARCK, N.D. (AP) — Texas-based Energy Transfer Partners is gauging the interest among oil shippers in moving more crude through the Dakota Access pipeline.

The $3.8 billion pipeline moves North Dakota oil through South Dakota and Iowa to a shipping point in Illinois. From there it goes to the Gulf Coast.

ETP is seeking commitments from shippers to transport additional oil. The proposed expansion would increase the pipeline’s capacity from 500,000 barrels per day to 570,000 barrels.

Company spokeswoman Vicki Granado tells The Bismarck Tribune that the expansion would require minimal modifications to the actual pipeline.

North Dakota Pipeline Authority Director Justin Kringstad says companies can increase pipeline capacity by adding a chemical to make oil flow more easily, or by adding more pumping power or pumping stations.