|  EXHIBIT 10.5.8                                   |
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|  Union Carbide Corporation and Subsidiaries  |

| 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: |
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| 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. |
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| 3. | Execution in Counterparts. This amendment may be executed in any number of counterparts and 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. |
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| 4. | Governing Law. This Amendment and the rights and obligation of the Parties to this Amendmentwill be governed by, and construed and interpreted in accordance with, the law of the State of New York. |
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| 5. | Subsidiary Guarantors.  The Guarantors to this Agreement will only be bound by their guarantees if they remain a wholly owned subsidiary of the Borrower. |
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| LENDER:                                                                                                                                                                                                                                                                                                                                         | SUBSIDIARY GUARANTORS:                                                                                                                                                                                          |
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| THE DOW CHEMICAL COMPANY  By: /s/ FERNANDO RUIZ                Name:         Fernando RuizTitle:           Corporate Vice President and Treasurer | UNION CARBIDE SUBSIDIARY C, INC.  By: /s/ MICHAEL L. GLENN            Name:  Michael L. GlennTitle:    Secretary |

| BORROWER:                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |                                                                                                                                                                                                                  |
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|  UNION CARBIDE CORPORATION By: /s/ EUDIO GIL                            Name:     Eudio GilTitle:       Chief Financial Officer, Vice President, and                Treasurer | UNION CARBIDE CHEMICALS & PLASTICS TECHNOLOGY LLC  By: /s/ MARK A WHITEMAN        Name:  Mark A. WhitemanTitle:    Vice President |

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