Nos. 89-1691, 90-1473. Argued April 25, 1991. Decided August 27, 1991. Gerard Morales, with whom William P. Allen, Phoenix, Ariz., was on the brief, for petitioner in 89-1691 and 90-1473. Beverly A. Oyama, Atty., N.L.R.B., with whom Jerry M. Hunter, Gen. Counsel, D. Randall Frye, Acting Deputy Gen. Counsel, Aileen A. Armstrong, Deputy Associate Gen. Counsel, and Collis Suzanne Stocking, Supervisory Atty., N.L.R.B., Washington, D.C., were on the brief, for respondent in both cases. Howard E. Perlstein