t when they entered the bargaining unit. Paperworkers Local 1033 (Weyerhaeuser Paper Co.}, 320 NLRB 349, 350 (1995), rev’d. on other grounds sub nom. Buzenius v. NLRB, 124 F.3d 788 (6th Cir. 1997), vacated sub nom. United Paperworkers Intern. Union v. Buzenius, 525 U.S. 979 (1998). (4) When an employer volu