In Dubuque Packing Co., 303 N.L.R.B. 386 (1991), the Board established a test for deciding "whether a decision to relocate unit work is a mandatory subject of bargaining," holding that such a decision was within the third First National category. 303 N.L.R.B. at 390. The Board held that the initial burden in a relocation case rests with NLRB's General Counsel, who must "establish that the employer's decision involved a relocation of unit work unaccompanied by a basic change in the nature of the employer's operation." Id. at 391. If the General Counsel meets that burden, a prima facie case has been established that the relocation is a mandatory subject of bargaining. Id. The employer can then make out a defense to the prima facie case by showing that (1) "labor costs (direct and/or indirect) were not a factor in the decision"; or (2) "even if labor costs were a factor . . . , the union could not have offered labor cost concessions that could have changed the employer's decision to relocate." Id.