Exhibit 21

SUBSIDIARY LIST

(as of February 27, 2013)

Company Name Place of Incorporation

Bayou Coating, L.L.C.1 Bayou Perma-Pipe Canada, Ltd.2 Bayou Wasco Insulation, LLC 3 Commercial Coating Services International, LLC Corrpower International Limited 4 Corrpro Canada Holdings, Inc. Corrpro Canada, Inc. Corrpro Companies Europe Ltd. Corrpro Companies, Inc. Corrpro Companies International, Inc. Corrpro Holdings LLC CRTS, Inc. Delta Double Jointing, LLC 5 Energy & Mining Holding Company, LLC Fibrwrap Construction Chile S.A. 6 Fibrwrap Construction Colombia S.A.S. 7 Fibrwrap Construction Latin America S.A. Fibrwrap Construction (M) Sdn Bhd Fibrwrap Construction Peru S.A.C. 8 Fibrwrap Construction Pte Ltd Fibrwrap Construction Services, Inc. Fibrwrap Construction Services Ltd. Fibrwrap Construction Services USA, Inc. Fyfe Asia Pte. Ltd. Fyfe Borneo Sdn Bhd 9 Fyfe Co. LLC Fyfe International Holdings B.V. Fyfe (Hong Kong) Limited Fyfe Japan Co. Ltd. Fyfe – Latin America S.A. Fyfe – Latin America S.A. de C.V. Grupo Meltzer Fibrwrap Costa Rica S.A. 10 Hockway Middle East FZE INA Acquisition Corp. Infrastructure Group Holdings, LLC Insitu Envirotech (S.E. Asia) Pte. Ltd. Insituform Asia Limited Insituform Belgium N.V. Insituform CV Insituform Cyprus Limited Insituform Environmental Techniques Ltd. 11 Insituform Europe SAS Insituform Holdings BV Insituform Holdings (UK) Limited Insituform Hong Kong Limited Insituform-Hulin Rohrsanierungstechniken S.R.O. 12 Insituform Hulin Kft.  13 Insituform Limited Partnership Insituform Linings Asia Sdn Bhd Insituform Linings Limited Louisiana Alberta, Canada Delaware Texas Saudi Arabia Delaware Alberta, Canada United Kingdom Ohio Nevada Delaware Oklahoma Delaware Delaware Republic of Chile Republic of Columbia Republic of Panama Malaysia Republic of Peru Singapore Delaware British Columbia, Canada Delaware Singapore Brunei Delaware The Netherlands Hong Kong Japan Republic of Panama Republic of El Salvador Republic of Costa Rica United Arab Emirates Delaware Delaware Singapore Hong Kong Belgium The Netherlands Cyprus Northern Ireland France The Netherlands United Kingdom Hong Kong Slovakia Hungary New Brunswick, Canada Malaysia United Kingdom

Insituform Pacific Pty Limited Insituform Pipeline Rehabilitation Private Limited Insituform Rioolrenovatietechnieken B.V. Insituform Rohrsanierungstechniken GmbH 14 Insituform Singapore Pte. Ltd. Insituform sp. z o.o. Insituform SPML JV 15 Insituform Technologies CV Insituform Technologies Ibérica S.A. Insituform Technologies Limited Insituform Technologies Limited Insituform Technologies, LLC Insituform Technologies Netherlands BV Insituform Technologies USA, LLC ITI International Services Canada Ltd. ITI International Services, Inc. KA-TE Insituform AG Mississippi Textiles Corporation Ocean City Research Corporation PT Fyfe Fibrwrap Indonesia 16 Specialized Fabrics, LLC Technologies & Art Pte. Ltd. The Bayou Companies, LLC Trubice Technike s.r.o. 17 United Pipeline de Mexico S.A. de C.V. 18 United Pipeline Middle East, Inc. United Pipeline Systems, Inc. United Pipeline Systems International, Inc. United Pipeline Systems Limited United Pipelines Inversiones Limitada United Pipelines SRL United Sistemas de Revestimento em Tubulações Ltda. United Sistema de Tuberias Limitada United Special Technical Services L.L.C. 19 UPS-Aptec Limited 20 Video Injection – Insituform SAS WCU Corrosion Technologies Pte. Ltd. 21 Wilson Walton Anti Corrosivos Ltd. Wilson Walton Group Ltd. Australia India The Netherlands Germany Singapore Poland India The Netherlands Spain Alberta, Canada United Kingdom Delaware The Netherlands Delaware Alberta, Canada Delaware Switzerland Mississippi New Jersey Indonesia Washington Singapore Delaware Czech Republic Mexico Delaware Nevada Delaware Alberta, Canada Chile Argentina Brazil Chile Sultanate of Oman United Kingdom France Singapore Portugal United Kingdom

1 The Bayou Companies, LLC holds a 49% interest in Bayou Coating L.L.C. The Bayou Companies, LLC holds a 59% interest in Delta Double Jointing, LLC and Bayou Coating L.L.C. holds the other 41% interest.

2 United Pipeline Systems Limited (Canada) holds a 51% interest.

3 Energy & Mining Holding Company, LLC holds a 51% interest.

4 Corrpro Canada, Inc. holds a 70% interest.

5 See Note 1.

6 Fibrwrap Construction Latin America S.A. holds a 55% interest.

7 Fibrwrap Construction Latin America S.A. holds a 51% interest.

8 Fibrwrap Construction Latin America S.A. holds a 51% interest.

9 Fyfe Asia Pte. Ltd. holds a 51% interest.

10 Fibrwrap Construction Latin America S.A. holds a 51% interest.

11 Insituform Technologies Limited (UK) holds a 50% interest.

12 Insituform Technologies Limited (UK) holds a 50% interest in Insituform Rohrsanierungstechniken GmbH. Insituform Rohrsanierungstechniken GmbH holds a 51% interest in Instuform-Hulin Rohrsanierungstechniken S.R.O. (Slovakia). Insituform-Hulin Rohrsanierungstechniken S.R.O. holds a 100% interest in Insituform Hulin Kft. (Hungary) and Trubice Technike s.r.o (f/k/a Insituform s.r.o.) (Czech Republic).

13 See Note 12.

14 See Note 12.

15 Insituform Technologies, LLC holds a 99.9% interest.

16 Fyfe Asia Pte. Ltd. holds a 55% interest.

17 See Note 12.

18 INA Acquisition Corp. holds a 55% interest.

19 Insituform Technologies Netherlands BV holds a 51% interest.

20 United Pipeline Systems International, Inc. holds a 51 interest.

21 Insituform Technologies Netherlands BV holds a 49% interest.