No. 79-1568. Argued February 11, 1980. Decided April 14, 1980. Donald L. Dotson (argued), Francis P. Massco, Pittsburgh, Pa., for petitioner. Candace M. Carroll (argued), Norton J. Come, Acting Gen. Counsel, John E. Higgins, Jr., Deputy Gen. Counsel, Robert E. Allen, Acting Associate Gen. Counsel, Elliott Moore, Deputy Associate Gen. Counsel, N.L.R.B., Washington, D.C., for respondent. Petition for review from the National Labor Relations Board. Before ADAMS, VAN DUSEN and GARTH, Circuit Judges.