The cause of the rupture, which sparked a wildfire in a remote part of Yellowhead County, is still under investigation.
"We have stood down our Yellowhead County incident emergency response and transitioned to the repair and restoration phase," a TC Energy spokesperson said, adding that the company was continuing to work with regulators.
The NGTL is TC Energy's natural gas gathering and transportation system, which transports gas produced in the Western Canadian Sedimentary Basin (WCSB) to markets in Canada and United States.