No. 72-1150. Argued November 2, 1972. Decided January 23, 1973. Paul J. Spielberg, Atty., N.L.R.B., with whom Marcel Mallet-Prevost, Asst. Gen. Counsel, N.L.R.B., was on the brief, for petitioner. John M. Bray, Washington, D.C., with whom Allen G. Siegel, Washington, D.C., was on the brief, for respondents, David J. Berman, Washington, D.C., also entered an appearance for respondents. Petition from the National Labor Relations Board. Before TAMM and LEVENTHAL, Circuit Judges, and CHARLES E. WYZANSKI