The GMA Cover Corp. which was a U.S. Defense Department supplier which manufactured camouflaged cover systems for military applications, closed the doors on its last building in the city of Port Huron this week, just about a week after the city revoked a tax exemption. According to reports many employees received a text about the closure and were given permanent layoff notices upon arrival at the business on Tuesday. The doors are now closed and locked at the building located at 2401 16th Street in Port Huron. Over 150 employees had been laid off last summer, when the companies Dove Street plant was closed. Employees stated they were not aware of a coming closure, and they say this puts a great number of area people in a tough spot, right before the winter season, when household expenses can be high.