The all-stock deal, which valued Spectra at $37 billion when it was announced last September, still requires approval under the Canadian Competition Act.
Enbridge (TSX:ENB) said Thursday that as part of the clearance by the FTC, it will keep some information related to the Discovery offshore Gulf of Mexico natural gas pipeline system separate from Enbridge itself.
Spectra owns an indirect interest in the Discovery system, while Enbridge, through an affiliate, also has offshore natural gas gathering operations in the region.
On Wednesday, Enbridge said it had closed a deal to acquire a 27.6 per cent interest in the Bakken Pipeline System, which includes the Dakota Access Pipeline which has been subject to extensive protests by the Standing Rock Sioux tribe and others.
The US$1.5-billion deal was expected to close last year before protests escalated and brought the project into doubt, but the election of U.S. President Donald Trump has helped clear regulatory hurdles for the project.