**EXHIBIT 10.5.3**

 

**Third Amendment to the**

**Amended and Restated Revolving Credit Agreement**

 

This Third Amendment to the Amended andRestated Revolving Credit Agreement (this “Amendment”) is made effectiveas of September 30, 2005 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 & PlasticsTechnology Corporation as the Subsidiary Guarantors (the “SubsidiaryGuarantors”) (together, the “Parties”).

 

BACKGROUND

 

The Parties have entered into the Amended andRestated Revolving Credit Agreement dated as of May 28, 2004, as amended by theFirst Amendment to the Amended and Restated Revolving Credit Agreement datedOctober 29, 2004 and the Second Amendment to the Amended and Restated RevolvingCredit Agreement dated December 30, 2004 (the “Credit Agreement”).

 

The Parties desire to amend the CreditAgreement 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 CreditAgreement.

 

THEAGREEMENT

 

1.             Amendmentto Section 1.1.  The Parties agree toamend Section 1.1 of the Credit Agreement by replacing the definitions of “LIBOR”and “Scheduled Termination Date” in their entirety with the followingdefinitions:

 

“‘*LIBOR*’means the rate of interest announced publicly by the British BankersAssociation as its one (1) month LIBOR rate for U.S. Dollars on the date thatis two Business Days prior to the first day of the applicable period for whichsuch interest is payable.

 

‘*Scheduled Termination Date*’ means December 30, 2006.”

 

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

 

3.             Execution in Counterparts.  This Amendment may be executed in any numberof counterparts and by different Parties in separate counterparts, each ofwhich when so executed will be deemed to be an original and all of which takentogether will constitute one and the same agreement.  Signature pages may be detached from multipleseparate counterparts and attached to a single counterpart so that allsignature pages are attached to the same document.

 

4.             Governing Law. This Amendment and the rights and obligations of the Parties to thisAmendment will be governed by, and construed and interpreted in accordancewith, the law of the State of New York.

 

[Signature pages follow.]

 

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TheParties agree that this Amendment is effective as of September 30, 2005, andthey have caused their authorized representatives to execute this Amendmentbelow.

 
| **LENDER:**                     |                                                    | **SUBSIDIARY GUARANTORS:**                                               |
|--------------------------------------|---------------------------------------------------------|--------------------------------------------------------------------------|
| ** **                           | ** **                                              | ** **                                                               |
| **THE  DOW CHEMICAL COMPANY**        | ** **                                              | **UNION CARBIDE SUBSIDIARY C,  INC.**                                    |
| ** **                           | ** **                                              | ** **                                                               |
| ** **                           | ** **                                              | ** **                                                               |
| By:                                  | /s/ J. P. REINHARD                                      | ** **                                                               | ** ** | By: | /s/ JOHN P. YIMOYINES | ** ** |
| Name:                                | J. P. Reinhard                                          |                                                                     | Name: | John P. Yimoyines |
| Title:                               | Executive Vice  President and  Chief Financial Officer  |                                                                     | Title: | President |
|                                 |                                                    |                                                                     | ** ** | ** ** |
| **BORROWER:**                        |                                                    | **UNION CARBIDE CHEMICALS &  PLASTICS TECHNOLOGY CORPORATION**  |
|                                 |                                                    |                                                                     | ** ** | ** ** |
| **UNION  CARBIDE CORPORATION**  |                                                    | ** **                                                               | ** ** |
|                                 |                                                    |                                                                     | By: | /s/ ALEXANDER J. MAKAI | ** ** |
|                                 |                                                    |                                                                     | Name: | Alexander J. Makai |
| By:                                  | /s/ EDWARD W. RICH                                      |                                                                     |   | Title: | President |
| Name:                                | Edward W. Rich                                          |                                                                     | ** ** | ** ** |
| Title:                               | Chief Financial  Officer, Vice President and  Treasurer |                                                                     | ** ** | ** ** |
|                                      |                                                         |                                                                          |  |  |  |  |  |  |

 

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