Aegion Corporation Awarded $10 Million Contract From the City of Baltimore, Maryland

Aegion Corporation (“Aegion” or the “Company”) (Nasdaq Global Select Market: AEGN) today announced that its subsidiary, Insituform Technologies, LLC (“Insituform”), has been awarded a contract valued at approximately $10 million from the City of Baltimore, Maryland. Including this latest contract, the City of Baltimore has awarded Insituform $56.9 million in contracts since September 2012.

Insituform will install nearly seven miles of small- and medium-diameter Insituform® cured-in-place pipe (CIPP) in wastewater pipelines located throughout the Baltimore area. Approximately one mile of the installation will be for medium-diameter trunk sewers.

Jeff Kowal, Vice President and General Manager of Insituform’s East Region, said, “We are pleased the City of Baltimore has entrusted us to execute this technically challenging wastewater rehabilitation project, which will require a large bypass system and effective traffic control in the city center and Inner Harbor areas. Our engineers and crews are well prepared to successfully complete this project while minimizing the disruption for citizens and businesses.”

Work on the project is expected to begin in mid-2014 and will take approximately 16 months to complete.

About Aegion Corporation

Aegion Corporation is a global leader in infrastructure protection and maintenance, providing proprietary technologies and services: (i) to protect against the corrosion of industrial pipelines; (ii) to rehabilitate and strengthen water, wastewater, energy and mining piping systems and buildings, bridges, tunnels and waterfront structures; and (iii) to utilize integrated professional services in engineering, procurement, construction, maintenance and turnaround services for a broad range of energy related industries. More information about Aegion can be found on our internet site at www.aegion.com.

About Insituform Technologies, LLC

For over forty years, Insituform Technologies, LLC, a subsidiary of Aegion Corporation, has been a global leader in the development and installation of proprietary technologies and services for rehabilitating sewer, water and other underground piping systems without digging or disruption. More information about Insituform Technologies can be found on its Internet site at www.insituform.com.

Forward-Looking Statements

The Private Securities Litigation Reform Act of 1995 provides a “safe harbor” for forward-looking statements. The Company makes forward-looking statements in this news release that represent the Company’s beliefs or expectations about future events or financial performance. These forward-looking statements are based on information currently available to the Company and on management’s beliefs, assumptions, estimates or projections and are not guarantees of future events or results. When used in this document, the words “anticipate,” “estimate,” “believe,” “plan,” “intend,” “may,” “will” and similar expressions are intended to identify forward-looking statements, but are not the exclusive means of identifying such statements. Such statements are subject to known and unknown risks, uncertainties and assumptions, including those referred to in the “Risk Factors” section of the Company’s Annual Report on Form 10-K for the year ended December 31, 2013, as filed with the Securities and Exchange Commission on February 28, 2014, and in the Company’s subsequent quarterly reports on Form 10-Q. In light of these risks, uncertainties and assumptions, the forward-looking events may not occur. In addition, the Company’s actual results may vary materially from those anticipated, estimated, suggested or projected. Except as required by law, the Company does not assume a duty to update forward-looking statements, whether as a result of new information, future events or otherwise. Investors should, however, review additional disclosures made by the Company from time to time in its periodic filings with the Securities and Exchange Commission. Please use caution and do not place reliance on forward-looking statements. All forward looking-statements made by the Company in this news release are qualified by these cautionary statements.

Aegion®, Insituform®and the Aegion® logo are the registered and unregistered trademarks of Aegion Corporation and its affiliates.