The project won preliminary plan approval from Johnston's Planning Board on Tuesday night. The vote was unanimous. The preliminary plan calls for construction of a proposed distribution center 120 feet high and encompassing 3,864,972 square feet across six levels, including a mezzanine occupied largely by robotic machinery. That square footage puts the proposed structure in league with some of the country's largest buildings. The site is a parcel of 195 acres off Hartford Avenue, near Route 295. "We're excited about the project," said Alex Escamilla, head of development for Bluewater Property Group. "There's going to be a lot of great benefits from it if it all goes through."