No. 86-3641. Argued June 19, 1987. Decided September 25, 1987. David Silberman, Laurence Gold (argued), Michael R. Fanning, Intern. Union of Operating Engineers, Washington, D.C., Paul A. Montalbano (argued), David Solomon, Schneider, Cohen, Solomon, Leder and Montalbano, Jersey City, N.J. (Michael H. Gottesman, Robert M. Weinberg, David A. Sklansky, Washington, D.C., of counsel), for petitioner. Robert E. Allen, Victoria A. Higman (argued), Elliott Moore, Rosemary M. Collyer, N.L.R.B., Washington