EXHIBIT
10.5.4


Fourth Amendment to the

Amended and Restated Revolving Credit Agreement


This Fourth Amendment to the Amended and Restated Revolving Credit
Agreement (this “Amendment”) is made effective as of September 30, 2006 and is
entered into between Union Carbide Corporation, as Borrower (“Borrower”),
The Dow Chemical Company, as Lender (“Lender”) and Union Carbide
Subsidiary C, Inc. and Union Carbide Chemicals & Plastics Technology
Corporation as the Subsidiary Guarantors (the “Subsidiary Guarantors”) (together,
the “Parties”).


BACKGROUND


The Parties have entered into the Amended and Restated Revolving Credit
Agreement dated as of May 28, 2004, as amended by the First Amendment to the
Amended and Restated Revolving Credit Agreement dated October 29, 2004 the
Second Amendment to the Amended and Restated Revolving Credit Agreement dated
December 30, 2004 and the Third Amendment to the Amended and Restated Revolving
Credit Agreement dated September 30, 2005 (the “Credit Agreement”).


The Parties desire to amend the Credit Agreement according to the terms
in this Amendment.  Any capitalized terms
used in this Amendment, but not otherwise defined in this Amendment, are as
defined in the Credit Agreement.


THE AGREEMENT


1.             Amendment to Section 1.1.  The Parties agree to amend Section 1.1 of the
Credit Agreement by replacing the definition of 
“Scheduled Termination Date” with the following definition:


“‘Scheduled Termination Date’ means December 30, 2007.”


2.             No Other
Amendment or Waiver.  Except as
expressly amended by this Amendment, the Credit Agreement and all other Loan
Documents remain in full force and effect in accordance with their terms, and
the Parties ratify and confirm the Credit Agreement and all other Loan
Documents in all respects.


3.             Execution in Counterparts.  This amendment may be executed in any number
of counterparts and by different parties in separate counterparts, each of
which when so executed will be deemed to be an original and all of which taken
together will constitute one and the same agreement.  Signature pages may be detached from multiple
separate counterparts and attached to a single counterpart so that all
signature pages are attached to the same document.


4.             Governing Law. 
This Amendment and the rights and obligation of the Parties to this
Amendment will be governed by, and construed and interpreted in accordance
with, the law of the State of New York.


[Signature pages
follow.]



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The Parties agree
that this Amendment is effective as of September 30, 2006, and they have caused
their authorized representatives to execute this Amendment below.


	
  LENDER:

  	
   

  	
  SUBSIDIARY GUARANTORS:

  
	
   

  	
   

  	
   

  
	
  THE DOW CHEMICAL COMPANY

  	
   

  	
  UNION CARBIDE SUBSIDIARY C, INC.

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  By:

  	
  /s/ GEOFFERY E. MERSZEI

  	
   

  	
  By:

  	
  /s/ JAMES R. FITTERLING

  
	
  Name:

  	
  Geoffery E. Merszei

  	
   

  	
  Name:

  	
  James R. Fitterling

  
	
  Title:

  	
  Executive Vice President and

  	
   

  	
  Title:

  	
  President

  
	
   

  	
  Chief Financial Officer

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  	
   

  	
   

  
	
  BORROWER:

  	
   

  	
  UNION CARBIDE CHEMICALS &

  
	
   

  	
   

  	
   

  	
  PLASTICS TECHNOLOGY

  
	
  UNION CARBIDE CORPORATION

  	
   

  	
  CORPORATION

  
	
   

  	
   

  	
   

  
	
   

  	
   

  	
   

  
	
  By:

  	
  /s/ EDWARD W. RICH

  	
   

  	
  By:

  	
  /s/ ALEXANDER J. MAKAI

  
	
  Name:

  	
  Edward W. Rich

  	
   

  	
  Name:

  	
  Alexander J. Makai

  
	
  Title:

  	
  Chief Financial Officer, Vice President

  	
   

  	
  Title:

  	
  President

  
	
   

  	
  and Treasurer

  	
   

  	
   

  	
   

  



 



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