Arizonas outgoing Gov. Doug Ducey (R) has spent months ordering work crews to erect shipping containers along the states southern border with Mexico in defiance of the federal government.

The Associated Press reported Sunday that Ducey, who is set to leave office due to term limits in January, first directed crews to close gaps in former President Donald Trump s border wall in August. Ducey issued an executive order to begin construction, and the state initially spent $6 million erecting a double-height barrier of containers in Yuma, Arizona, filling in about 3,800 feet of the border.

His office expanded the project in recent months, placing thousands of additional containers that stretch for miles through Coronado National Forest near Tucson. That effort could eventually stretch 10 miles at a cost of $95 million, which has prompted concern from environmentalists, tribal governments and the federal government.