Houston-based Plains All American Pipeline is cleaning up a nearly 19,000-gallon oil spill in Loyal, about 60 miles northwest of Oklahoma City.
The spill, which threatened a local water supply, affected about 70 acres of farmland and reached a small creek, but was contained before it flowed into a second creek that flows into the Cimarron River about 16 miles away, an Oklahoma Corporation Commission spokesman said.
The Corporation Commission and the Environmental Protection Agency are monitoring the cleanup.
Officials aren't sure when the spill started.