According to Wisconsin state officials, Interpane Glass Co. has filed a plant closing notice for its operations in Deerfield, Wis. While the exact closing date is not known, the state law requires companies to file notice of plant closings 60 days in advance.

In Clinton, N.C., where Interpane's North American operations are headquartered, the city manager there said the operations would be shutting down on July 9.

Joern Hesselbach, Interpane chief executive officer and Thomas Koehler, president, were both contacted for comment, but neither was available.