Boilermakers Local No. 374 v. N.L.R.B

In Boilermakers, 852 F.2d at 1353, and later in Plumbers Pipe Fitters Local Union No. 32 v. NLRB, 50 F.3d 29, 34 (D.C. Cir. 1995), this court set forth the parameters of the heightened duty standard in hiring hall cases.