WASHINGTON, Kan. – The massive Keystone Pipeline has been shut down after oil was found to be leaking into a Kansas creek.

TC Energy said it shut down the pipeline at 8 p.m. Wednesday after a pressure drop in the system. Crews are responding to “contain and recover the oil,” the company said in a news release.

“Our primary focus right now is the health and safety of onsite staff and personnel, the surrounding community, and mitigating risk to the environment through the deployment of booms downstream as we work to contain and prevent further migration of the release,” the company said.

The oil release is 20 miles south of Steel City, Neb., on the Kansas/Nebraska border, a major junction for the 2,687-mile pipeline system. The pipeline runs from Canada down through South Dakota to Steele City, where it splits. One arm runs east through Missouri, the other heads toward Oklahoma. More than 3 billion barrels of crude oil have been transported on the pipeline since it began operation in 2010.