Nos. 82-1767, 82-1903. Argued April 3, 1984. Decided September 26, 1984. Alan G. Burton, argued, E.I. DuPont de Nemours Co., Legal Dept., Wilmington, Del., George E. Yund, Frost Jacobs, Cincinnati, Ohio, for petitioner. Elliott Moore, L. Pay Wynns, argued, Deputy Associate Gen. Counsel, N.L.R.B., Washington, D.C., for respondent. Petition for review from the National Labor Relations Board. Before LIVELY and WELLFORD, Circuit Judges, and GIBSON, District Judge. The Honorable Benjamin F. Gibson, United