No. 90-1467. Submitted December 13, 1990. Decided October 4, 1991. Rehearing and Rehearing En Banc Denied December 4, 1991. Frederick Havard, Washington, D.C., argued (Jerry M. Hunter, Robert E. Allen and Aileen A. Armstrong, Washington, D.C., on brief), for petitioner. William Harding, Lincoln, Neb., argued (Jack L. Shultz and Jerry L. Pigsley, Lincoln, Neb., and Cecil R. Hedger, Denver, Colo., on brief), for respondent. Petition for enforcement of order from National Labor Relations Board. Before