THIRD AMENDMENT TO CONSTRUCTION LOAN AGREEMENT

EXHIBIT 10.10

THIRD AMENDMENT

TO CONSTRUCTION LOAN AGREEMENT

This THIRD AMENDMENT TO CONSTRUCTION LOAN AGREEMENT (this “ Agreement ”), dated as of September 18, 2006, is entered into by and among the following parties:

(a) TIETEK LLC, a Delaware limited liability company (the “ Borrower ”);

(b) NORTH AMERICAN TECHNOLOGIES GROUP, INC., a Delaware corporation (the “ Company ”), and TIETEK TECHNOLOGIES, INC., a Texas corporation (“ TTT ”) (the Company and TTT shall be collectively referred to as the “ Borrower Affiliates ” and the Borrower Affiliates and the Borrower shall be collectively referred to as the “ Borrower Group ”); and

(c) OPUS 5949 LLC (formerly known as Tie Investors, LLC), a Texas limited liability company (the “ Lender ” and, together with the Borrower Group, the “ Parties ”).

RECITALS

A. The Borrower, the Borrower Affiliates, and the Lender entered into that certain Construction Loan Agreement, dated as of February 5, 2004, as amended by (i) that certain Release, dated February 22, 2005, by and among the Parties, (ii) that certain Limited Waiver and First Amendment to Construction Loan dated July 7, 2005, by and among the Parties, and (iii) that certain Second Amendment to Construction Loan Agreement dated as of December 29, 2005, by and among the Parties (as so amended, the “ Loan Agreement ”), pursuant to which the Lender agreed to make available to the Borrower Group certain financial accommodations,

B. The Borrower and the Borrower Affiliates have requested that, subject to the terms, conditions, covenants and limitations contained in this Agreement, the Lender amend certain terms and conditions of the Loan Agreement and the Note to defer the payment of principal on the Note in the manner set forth below.

C. The Lender has agreed to the actions described in Paragraph B preceding, in each instance upon and subject to the terms, conditions, covenants and limitations contained in this Agreement.

ACKNOWLEDGEMENTS:

(a) The Borrower and the Borrower Affiliates hereby acknowledge and agree to the accuracy of all Recitals included in this Agreement.

(b) The Borrower and the Borrower Affiliates acknowledge and agree that all amounts advanced to, or for the benefit of, the Borrower, including, but not limited to, the Loan (as defined

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in the Loan Agreement) prior to the date hereof are, and shall continue to be, obligations under the Loan Documents (the “ Obligations ”) and subject to all the terms and conditions in the Loan Agreement and the other Loan Documents, in each instance as amended and modified by this Agreement.

(c) The Borrower and the Borrower Affiliates acknowledge and agree that (i) as of September 15, 2006, the outstanding principal and accrued but unpaid amount of the Obligations is $14,209,611, of which $14,000,000.00 is the amount of outstanding principal of the Note and $209,611 is the amount of accrued but unpaid interest thereon; and (ii) the Obligations are enforceable against the Borrower without offset, reduction, or counterclaim.

AGREEMENTS

NOW, THEREFORE, in consideration of the premises herein contained and other good and valuable consideration, the sufficiency of which is hereby acknowledged, the Parties hereto, intending to be legally bound, agree to the above Recitals, Acknowledgments and as follows:

1. DEFINITIONS . All capitalized terms used but not otherwise defined in this Agreement shall have the meanings ascribed to them in the Loan Agreement.

2. AMENDMENTS TO LOAN DOCUMENTS .

2.1 The following definitions in Section 1.1 of the Loan Agreement are hereby amended and restated in their entirety to read as follows:

“Loan Documents” This Agreement, the Limited Waiver and First Amendment to Construction Loan Agreement dated as of July 7, 2005, the Second Amendment to Construction Loan Agreement dated as of December 29, 2005, this Third Amendment to Construction Loan Agreement dated as of the date hereof, the Note, the Deed of Trust, the Security Agreement, the Patent Security Agreement, the Intercreditor Agreement, the Voting Agreement, the Non-Compete Agreement, the NATK Royalty Agreement, the TieTek Royalty Agreement, the Membership Pledge Interest Agreements, the Solvency Certificates, and any other documents to be executed by Borrower or any of their respective shareholders pertaining to the Loan, and as the same may be amended from time to time.

“Note” collectively, (i) that certain Second Amendment to Amended and Restated Promissory Note, dated as of the date hereof, in the stated principal amount of $14,000,000, made by TieTek LLC, payable to the order of the Lender, (ii) any other promissory notes evidencing any portion of the Loan, including any instruments amended and restated by the instrument referred to in clause (i) immediately preceding, and (iii) any promissory notes or other agreement evidencing any renewals, extensions, increases, amendments, modifications, restatements or payment-in-kind in respect of any of the foregoing.”

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2.2 All references to the “Loan Agreement” or the “Construction Agreement” or other similar terms intended to refer to the Loan Agreement in each of the Loan Documents and in any other documents or agreements by, between or among any of the Borrower Group and their respective affiliates, and or for the benefit of the Lender will from and after the date hereof refer to the Loan Agreement, as amended hereby, and all obligations of the Borrower Group under the Loan Agreement, as amended hereby, shall be secured by and be entitled to the benefits of said Loan Documents and such other documents and agreements. All Loan Documents heretofore executed by all or any of the Borrower Group shall remain in full force and effect to secure the Loan (as defined in the Loan Agreement), and such Loan Documents, as amended hereby, are hereby ratified and affirmed.

3. CONDITIONS PRECEDENT TO EFFECTIVENESS . The effectiveness of this Agreement is subject to the fulfillment of each of the following terms and conditions to the satisfaction of Lender in its sole discretion at or before 2:00 p.m. (Dallas time) on September 30, 2006.

3.1. The Lender shall have received fully executed copies of the Securities Purchase Agreement dated as of September 15, 2006 (the “2006 SPA”) among the Company and certain purchasers of shares of common stock and warrants named therein (the “Purchasers”), in form and substance satisfactory to Lender.

3.2. The Lender shall have received a legal opinion of the Borrower’s counsel in form and substance satisfactory to the Lender as to much matters as Lender may request with respect to each member of the Borrower Group, this Agreement, the Loan Agreement, the other Loan Documents and each agreement and instrument delivered in connection with, or contemplated by, this Agreement.

3.3 The Lender shall have received evidence satisfactory to the Lender that each Purchaser deposited its full Subscription Amount pursuant to the Escrow Agreement.

3.4. The Lender shall have received the Second Amendment to Amended and Restated Promissory Note in form of attached hereto as Exhibit A, appropriately executed by TieTek LLC.

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4. LENDER CONSENT . By execution hereof, Lender hereby consents to (i) the amendment to the Note to provide that all amounts otherwise due under the Note shall become due on July 1, 2008 in the manner described in the Note and (ii) the transactions contemplated by the 2006 SPA.

5. RATIFICATIONS, REPRESENTATIONS AND WARRANTIES .

5.1. The terms and provisions set forth in this Agreement shall supersede all inconsistent terms and provisions set forth in the Loan Agreement and, except as expressly set forth in this Agreement, the terms and provisions of the Loan Agreement and each of the other Loan Documents are ratified and confirmed and shall continue in full force and effect. The Parties hereto agree that the Loan Agreement shall continue to be legal, valid, binding and enforceable in accordance with its terms.

5.2. The Borrower and the Borrower Affiliates hereby represent and warrant to the Lender as follows:

(a) the execution, delivery and performance of this Agreement and any and all other agreements executed and/or delivered in connection herewith or therewith have been authorized by all requisite action on the part of the Borrower and the Borrower Affiliates and will not violate (i) the Regulations of the Borrower; or (ii) the articles of incorporation or bylaws of any of the Borrower Affiliates;

(b) the representations and warranties contained in this Agreement, the Loan Agreement and the Loan Documents are true and correct in all material respects on and as of the date hereof as though made on and as of such date;

(c) no Default or Event of Default under the Loan Agreement or the Loan Documents has occurred or is continuing;

(d) the consummation of the transactions contemplated hereby will not (i) violate any provision of the organizational documents or governing instruments of the Borrower or either of the Borrower Affiliates, (ii) violate any judgment, order, ruling, injunction, decree or award of any court, administrative agency or governmental body against, or binding upon, the Borrower or either of the Borrower Affiliates, or (iii) constitute a violation by the Borrower or the Borrower Affiliates of any law or regulation of any jurisdiction applicable to the Borrower or the Borrower Affiliates;

(e) this Agreement was reviewed by the Borrower and the Borrower Affiliates, wh