RICHMOND, Va. (AP) — Both supporters and opponents of the Atlantic Coast Pipeline say Dominion Energy’s proposed merger with a South Carolina energy company could open the door to making the natural gas project even bigger.

Dominion CEO Tom Farrell said in a conference call announcing the deal this week that SCANA Corp. is a “natural fit” for Dominion, which already operates natural gas transmission pipelines in South Carolina.

Farrell said the deal could “open new expansion opportunities” for the proposed Atlantic Coast Pipeline, which is currently slated to run for 600 miles through West Virginia, Virginia and North Carolina and cost about $5 billion.

The massive infrastructure project has the support of business leaders and a bipartisan group of politicians in all three states. Environmental groups are strongly opposed.