JOINDER AGREEMENT TO THE SECURITY AGREEMENT November 9, 2015

Exhibit 10.5

JOINDER AGREEMENT TO THE SECURITY AGREEMENT

November 9, 2015

The undersigned, together with its successors and assigns (the “Purchaser”), in connection with the 12.0% Notes (defined below) wishes to become “Secured Parties” (together with each holder of the 12.0% Notes, collectively, the “New Secured Parties”) under the Security Agreement, dated as of August 7, 2013 (as amended and/or supplemented, the “Security Agreement” (terms used without definition herein have the meanings assigned to such terms by the Security Agreement)) among LSB Industries, Inc., the other Grantors party thereto and UMB Bank, n.a., as Collateral Agent (in its capacity as the collateral agent, the “Collateral Agent”) and the other Security Documents.

In consideration of the foregoing, the undersigned hereby:

(i) represents that it has full power and authority to become a party to the Security Agreement on behalf of the New Secured Parties under the Company’s 12.0% Senior Secured Notes Due 2019 issued pursuant to that certain Note Purchase Agreement, dated as of November 9, 2015 (the “12.0% Notes”);

(ii) acknowledges that the Purchaser has received a copy of the Security Agreement;

(iii) irrevocably appoints and authorizes the Collateral Agent to take such action as agent on its behalf and on behalf of the other New Secured Parties and to exercise such powers under the Security Agreement and the other Security Documents as are delegated to the Collateral Agent by the terms thereof, together with all such powers as are reasonably incidental thereto; and

(iv) accepts and acknowledges the terms of the Security Agreement applicable to it and the New Secured Parties and agrees on its own behalf and on behalf of the New Secured Parties to be bound by the terms of the Security Agreement and the other Security Documents applicable to holders of Secured Obligations, with all the rights and obligations of a Secured Party thereunder and bound by all the provisions thereof as fully as if it had been a Secured Party on the effective date of the Security Agreement.

THIS JOINDER AGREEMENT SHALL BE GOVERNED BY, AND SHALL BE CONSTRUED AND ENFORCED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK.

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In witness whereof, the parties have caused this Joinder Agreement to be duly executed as of the date first written above.

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Acknowledged and Agreed:

UMB BANK, N.A, as Collateral Agent

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