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                    FIRST AMENDMENT TO ASSIGNMENT AGREEMENT


     This FIRST AMENDMENT TO ASSIGNMENT AGREEMENT (this "First Amendment"), 
effective as of December 15, 1996 ("Effective Date"), is by and between THE 
DOW CHEMICAL COMPANY ("Dow"), a Delaware corporation with its principal 
offices at 2030 Dow Center, Midland, Michigan 48674, and DESTEC ENERGY, INC. 
("Destec") a Delaware corporation with its principal offices at 2500 CityWest 
Boulevard, Suite 150, Houston, Texas 77042.

                                RECITALS:

     A.   Dow and Destec entered into the Assignment Agreement effective as 
of March 1, 1990 (the "Agreement"), which assigns from Dow to Destec certain 
patents and technology pertaining to gasification of carbonaceous materials 
and to lignite; and

     B.   Dow and Destec desire to amend certain provisions of the Agreement.

     NOW, THEREFORE, in consideration of the mutual covenants and agreements 
set forth in this First Amendment, the receipt and sufficiency of which are 
mutually acknowledged, the parties agree as follows:

1.   Paragraph 3.1 of the Agreement is hereby deleted in its entirety and 
replaced by the following text:

     3.1  In consideration of the assignment contained in Paragraph 2.1 of 
     this Agreement, Destec hereby grants to Dow and to entities and 
     partnerships at least 49% owned by Dow (such entities and partnerships
     being collectively termed "Subsidiaries") a non-exclusive,
     royalty-free, worldwide license to practice the technology contained in
     the Know How, Patent Disclosures and Patent Properties for internal use by
     Dow or its Subsidiaries in their own facilities. This non-exclusive, 
     royalty-free, worldwide license includes any improvements made in the 
     technology by Destec or to which Destec has the right to sublicense between
     the Effective Date and the later of (i) December 31, 1997, or (ii) during
     any extension beyond December 31, 1997 of the term of the Research & 
     Development Agreement between Dow and Destec effective as of March 1, 1990,
     under which Dow provides to Destec certain research and development 
     services with respect to the intellectual property assigned under the 
     Agreement.

2.   Paragraph 3.2 of the Agreement is hereby deleted in its entirety and 
shall have no further force or effect after the Effective Date of this First 
Amendment.

3.   Article IV of the Agreement is hereby deleted in its entirety and shall 
have no further force or effect after the Effective Date of this First 
Amendment.

4.   Article V of the Agreement is hereby deleted in its entirety and shall 
have no further force or effect after the Effective Date of this First 
Amendment.

5.   Paragraph 6.4 of the Agreement is hereby amended by changing the address 
for notice to Dow to:

          The Dow Chemical Company
          Patent Department, 1790 Building
          Attn.: Patent General Counsel
          Midland, MI  48674

6.   Exhibits A, B and C of the Agreement are hereby deleted in their 
entirety and replaced with Exhibits A, B and C attached to this First 
Amendment.

7.   Except as amended by this First Amendment, the Agreement remains in full 
force and effect.

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     This First Amendment has been executed by authorized representatives of 
the parties. 

                                 THE DOW CHEMICAL COMPANY

                                 By:  /s/ B. G. Taylorson
                                     --------------------------
                                 Name:   B. G. Taylorson
                                 Title:  Corporate Director,
                                         Mergers & Acquisitions


                                 DESTEC ENERGY, INC.

                                 By:  /s/ Enrique M. Larroucau
                                     --------------------------
                                 Name:   Enrique M. Larroucau
                                 Title:  Senior Vice President,
                                         Chief Financial Officer
                                         and Treasurer