Nos. 94-70192, 94-70262 Argued and Submitted August 18, 1995 — San Francisco, California. Filed May 15, 1997 Robert G. Hulteng, Jeffrey S. Bosley, Littler, Mendelson, Fastiff, Tichy Mathiason, San Francisco, CA, for petitioner-cross-respondent, Gardner Mechanical Services, Inc. Charles Donnelly, John J. Fawley, Washington, DC, for respondent-cross-petitioner, National Labor Relations Board. John J. Davis, Jr., McCarthy, Johnson Miller, San Francisco, CA, for respondent-intervenor, U.S. Local 350