·  A.B. Myr Industries, Inc.
·  Air Design Systems, Inc.
·  Alberici Constructors, Inc.
·  American Airlines
·  Aristeo Construction Company
·  Aristeo Rigging & Erectors, LLC
·  Automatic Systems, Inc.
·  Av Air Pros
·  BAE Automated Systems, Inc.
·  BASF Corporation
·  BOC Gases
·  BP Products North America, Inc.
·  Brandenburg Industrial Services Company
·  Brose International
·  Chemical Waste Management
·  Chiyoda International Corp.  
·  City of Chicago - Department of Water
·  Chicago Park District
·  Chicago Transit Authority
·  Chicago Water Partners
·  Citgo Petroleum Corporation
·  Clark Chemical & Oil Company
·  CN Railroad
·  Comau Pico
·  CTE Engineers, Inc.
·  Dearborn Mid-west
·  Dominion Technologies Group, Inc.
·  Dow Chemical Company
·  Durr Systems, Inc.  
·  Fanuc Robotics America, Inc.
·  F.H. Paschen/S.N. Nielsen
·  Fluor Enterprises, Inc.
·  Ford Motor Company
·  General Mills, Inc.
·  Giffin, Inc.
·  Glenbrook North High School
·  Healey Fire Protection, Inc.
·  HK Systems, Inc.

·  Holcim Inc.
·  Hunt-Wesson, Inc. IHC Construction Companies, LLC
·  Independent Mechanical Industries
·  Ingalls Memorial Hospital
·  Inland Steel Company
·  Integrated Control Systems, Inc.
·  Innovative Technology
·  Inovision Software Solutions
·  International Industrial Contracting Corp.
·  Invensys Process Systems
·  J.J. Henderson & Son, Inc.
·  KLA Laboratories, Inc.
·  Lafarge Corporation
·  Lesco Design & Manufacturing Company, Inc.
·  Linde Group 
·  Matthew Controls, Inc.
·  Matra Transport International
·  Metra
·  Metropolitan Water Reclamation District of Greater Chicago
·  Micro-Poise Measurement Systems, Inc.
·  Midway Airport
·  Mitsubishi Motors Corp.
·  Nabisco
·  NIPSCO
·  North American Energy Group
·  Northern Petrochemical Company
·  Northrop Grumman Corporation
·  O’Hare International Airport
·  Olympia Fields Country Club
·  Overhead Conveyor Company
·  Procter & Gamble
·  Rapistan Demag Systems
·  Rausch Construction Co.
·  Rudolph Libbe Companies, Inc. 
·  Sandvik Group

·  SimplexGrinnell 
·  Smurfit-Stone
·  Square D Company
·  St. Mary’s Cement State Group Industrial Limited
·  State of Illinois – Capital Development Board
·  Subaru of America, Inc.
·  Sunoco, Inc.
·  Superior Controls, Inc.
·  Teng Construction, LLC
·  Thorn Creek Basin Sanitary District
·  Trigen Energy Corp.
·  United Parcel Service (UPS)
·  United Scrap Metal
·  U.S. Steel Corporation
·  University of Chicago
·  University of Illinois
·  Valero Energy Corporation
·  Valient Machine & Tool, Inc.
·  Visteon Corporation
·  Village of Alsip
·  Village of Flossmoor
·  Village of Franklin Park
·  Village of Homewood
·  Village of Lansing
·  Village of Mundelein
·  Village of Orland Park
·  Village of Palos Heights
·  Walbridge Equipment Installation, LLC
·  Walsh Group
·  Westin Engineering
·  Wisconsin Tissue