AAON, Inc.

AECOM Technology Corporation

Aavid Thermal Technologies, Inc.

Alliant Techsystems Inc.

Altran Technologies

American Science & Engineering, Inc.

Amey Plc

Analytic Sciences Corporation

Arcadis NV

Arthur D. Little, Inc.

BE&K, Inc.

Babcock International Group PLC

Balfour Beatty plc

Birse Group PLC

Brown & Root, Inc.

Bufete Industrial, S.A. de C.V.

C. H. Heist Corporation

CH2M Hill Ltd.

Coflexip S.A.

Corrections Corporation of America

DAW Technologies, Inc.

Dames & Moore, Inc.

Day & Zimmermann, Inc.

Donaldson Co. Inc.

Dycom Industries, Inc.

EG & G Incorporated

Edwards and Kelcey

Eiffage

Essef Corporation

FKI Plc

Fluor Corporation

Foster Wheeler Corporation

Foster Wheeler Ltd.

Framatome SA

Georg Fischer AG Schaffhausen

Gilbane, Inc.

Great Lakes Dredge & Dock Company

Grupo Dragados SA

HDR Inc.

HOK Group, Inc.

Halliburton Company

Harding Lawson Associates Group, Inc.

Harza Engineering Company

ICF Kaiser International, Inc.

IHC Caland N.V.

JWP Inc.

Jacobs Engineering Group Inc.

Klöckner-Werke AG

Kvaerner ASA

Layne Christensen Company

Malcolm Pirnie, Inc.

McDermott International, Inc.

McKinsey & Company, Inc.

Michael Baker Corporation

Nooter Corporation

Oceaneering International, Inc.

Odebrecht S.A.

Opus Group

Parsons Brinckerhoff, Inc.

Quanta Services, Inc.

RCM Technologies, Inc.

Renishaw plc

Rosemount Inc.

Roy F. Weston, Inc.

Royal Vopak NV

Rust International Inc.

SRI International, Inc.

SSOE Inc.

Sandvik AB

Sarnoff Corporation

Science Applications International Corporation

Serco Group plc

Siegel & Gale

Siemens AG

Stone & Webster, Inc.

Sulzer Ltd.

Sverdrup Corporation

TRC Companies, Inc.

Technip

Tetra Tech, Inc.

The Charles Stark Draper Laboratory, Inc.

The Judge Group, Inc.

The Keith Companies Inc.

The MacNeal-Schwendler Corporation

The PBSJ Corporation

Thyssen Krupp AG

Towers Perrin

Tracor Inc.

URS Corporation

Underwriters Laboratories, Inc.

United Dominion Industries Limited

VA TECH ELIN EBG GmbH

Vinci

WS Atkins Plc

Willbros Group, Inc.