No. 93-1479. Argued March 3, 1995. Decided April 25, 1995. Petition for Review of an Decision of the National Labor Relations Board. Patrick W. Ritchey, Pittsburgh, PA, argued the cause for the petitioner. On brief was Brooke Bashore-Smith, Newark, DE. Peter D. Post, Pittsburgh, PA, entered an appearance. Joseph J. Jablonski, Jr., Atty., N.L.R.B., Washington, DC, argued the cause for the respondent. On brief were Linda R. Sher, Acting Associate Gen. Counsel, Aileen A. Armstrong, Deputy Associate