Wynn Resorts said Tuesday the material was transported to licensed landfills across the country over the course of about seven months and filled more than 8,800 truckloads and 4,300 railcars.
The environmental work cost Wynn $30 million. The next phase is dredging the shoreline.
Wynn Boston Harbor is slated to open in summer of 2019 and will include a 671-room hotel, casino, a waterfront park and more. It is one of two resort casinos under construction in Massachusetts.