Nos. 90-3232, 90-3574. Argued May 6, 1991. Decided June 13, 1991. Rehearing and Rehearing En Banc Denied July 9, 1991. Raymond M. Deeny, Glenn H. Schlabs, Sherman Howard, Colorado Springs, Colo., for Laidlaw Waste Systems, Inc. John C. Truesdale, Robert N. Herman, N.L.R.B., Aileen A. Armstrong, Collis Suzanne Stocking, N.L.R.B., Appellate Court, Enforcement Litigation, Robert N. Herman, N.L.R.B., Washington, D.C., Elizabeth Kinney, N.L.R.B., Region 13, Chicago, Ill., for N.L.R.B. Petition for Review