The oil leak was discovered just north of Edinburg, in the northeastern part of the state, and touched about 2,500 square feet of land, the company said. A pressure drop was detected on Tuesday, and the pipeline was immediately shut down, the company said.
The company is not sure how the leak started, but says an independent party is investigating the pipeline.
"We are establishing air quality, water and wildlife monitoring and will continue to monitor throughout the response. No damage or wildlife impact has been reported," TC Energy said.
"Security for the public and the environment are our top priorities, and we will continue to provide updates as they become available."
The Indigenous Environmental Network, an environmental rights group, responded to the spill with concern.
"This is exactly the type of garbage we are concerned about when building the Keystone XL. It has never been if a pipeline breaks down, but rather when," said Joye Braun, organization manager for the Indigenous Environmental Network.
The organization criticized the company and said it had not done enough to secure the pipeline infrastructure.