CHANGE OF CONTROL AGREEMENT
This CHANGE OF CONTROL AGREEMENT (this “ Agreement ”) is entered into this 5th day of
February, 2007 (the “ Effective Date ”) between John M. Cooper (“ Employee ”) and AMERICAN
ECOLOGY CORPORATION, a Delaware corporation (the “ Company ”). This Agreement is intended to
provide Employee with the compensation and benefits described herein upon the occurrence of specific events
following a change of control of the ownership of the Company (defined as “ Change of Control ”). Certain
capitalized terms used in this Agreement are defined in Article 6 .
R E C I T A L S:
WHEREAS , it is expected that the Company from time to time may consider or may be presented with the
need to consider the possibility of an acquisition by another company or other change in control of the
ownership of the Company. The Board of Directors of the Company (the “ Board ”) recognizes that such
considerations can be a distraction to Employee and can cause the Employee to consider alternative
employment opportunities or be influenced by the impact of such possible change in control on Employee’s
personal circumstances. The Board has determined that it is in the best interests of the Company and its
stockholders to assure that the Company will have the continued dedication and objectivity of Employee,
notwithstanding the possibility or occurrence of a Change of Control of the Company; and
WHEREAS , the Board believes that it is in the best interests of the Company and its shareholders
to provide Employee with an incentive to continue his or her employment and to motivate Employee to
maximize the value of the Company upon a Change of Control for the benefit of its stockholders.
NOW, THEREFORE , the Company and Employee hereby agree as follows:
Article 1. EMPLOYMENT BY THE COMPANY.
1.1 Effect of Agreement . This Agreement shall commence on the Effective Date and shall
remain in full force and effect so lo