Nos. 95-3343 and 95-3399. Argued June 27, 1996. Filed January 31, 1997. Stephen J. Cabot (argued), Harvey, Pennington, Herting Renneisen, Philadelphia, PA, for Bro-Tech Corp. t/a Purolite. Aileen A. Armstrong, Richard A. Cohen (argued), National Labor Relations Board, Washington, DC, for National Labor Relations Board. On Petition for Review and Cross Application for Enforcement (Nos. 4-RC-17846 and 4-CA-234586) BEFORE: BECKER, NYGAARD and LEWIS, Circuit Judges. OPINION OF THE COURT BECKER, Circuit