AMENDMENT NO. 4

Exhibit 4.18(d)

AMENDMENT NO. 4

AMENDMENT dated as of September 25, 2006 to the RECEIVABLES PURCHASE AGREEMENT dated as of December 17, 2003 (as amended, the “Agreement”) among EQUISTAR RECEIVABLES II, LLC, a Delaware limited liability company (the “Seller”), EQUISTAR CHEMICALS, LP, a Delaware limited partnership (the “Servicer”), the PURCHASERS from time to time party thereto, CITICORP USA, INC., as co-asset agent and administrative agent for the Purchasers (the “Agent”), CREDIT SUISSE FIRST BOSTON, and JPMORGAN CHASE BANK, N.A. and WACHOVIA BANK, NATIONAL ASSOCIATION as co-documentations agents, and BANK OF AMERICA, N.A., as co-asset agent.

The parties hereto agree as follows:

SECTION 1. Defined Terms. Unless otherwise specifically defined herein, each term used herein which is defined in the Agreement has the meaning assigned to such term in the Agreement.

SECTION 2. Amended Definition. The definition of “Eligible Receivable” is hereby amended by (i) deleting the words “or, to the extent such Person is an Affiliate of any Originator, to LYONDELL-CITGO Refining LP or any of its subsidiaries” in the first paragraph thereof and (ii) deleting paragraph (c) thereof and inserting the word “[reserved;]” in the place thereof.

SECTION 3. Governing Law. This Amendment shall be governed by and construed in accordance with the laws of the State of New York.

SECTION 4. Counterparts. This Amendment may be signed in any number of counterparts, each of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument.

SECTION 5. Effectiveness. This Amendment shall become effective on the first date on which the Agent shall have received counterparts hereof signed by each of the Purchasers, the Seller and the Servicer (or, in the case of any party as to which an executed counterpart shall not have been received, receipt by the Agent in form satisfactory to it of telegraphic, telex or other written confirmation from such party of execution of a counterpart hereof by such party).

IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be duly executed as of the date first above written.

CITICORP USA, INC., as Agent
By:		/s/ Xxxxx Xxxxx
Name:		Xxxxx Xxxxx
Title:		Director / Vice President
EQUISTAR RECEIVABLES II, LLC, as Seller
By:		/s/ Xxxxx X. Xxxxxxxxx
Name:		Xxxxx X. Xxxxxxxxx
Title:		Vice President and Treasurer
EQUISTAR CHEMICALS, LP, as Servicer
By:		/s/ Xxxxx X. Xxxxxxxxx
Name:		Xxxxx X. Xxxxxxxxx
Title:		Vice President and Treasurer
ALLIED IRISH BANKS PLC
By:		/s/ Xxxxxx X. Xxxx
Name:		Xxxxxx X. Xxxx
Title:		SVP

F-1

AmSouth Bank
By:		/s/ Xxxxx Xxxxxx
Name:		Xxxxx Xxxxxx
Title:		Attorney in Fact

BANK OF AMERICA, N.A.
By:		/s/ Xxxxxxx Xxxx
Name:		Xxxxxxx Xxxx
Title:		Vice President

THE BANK OF NEW YORK
By:		/s/ Xxxxx Xxxxxxxxxxx
Name:		Xxxxx Xxxxxxxxxxx
Title:		Vice President

Calyon New York Branch
By:		/s/ Xxxxxx X. Xxxxxx
Name:		Xxxxxx X. Xxxxxx
Title:		Managing Director
By:		/s/ Page Dillehunt
Name:		Page Dillehunt
Title:		Managing Director

Commerzbank AG, New York and Grand Cayman Branches
By:		/s/ Xxxxxx Xxxxxxx
Name:		Xxxxxx Xxxxxxx
Title:		Vice President
By:		/s/ Xxxxx Xxx
Name:		Xxxxx Xxx
Title:		Assistant Treasurer

F-2

Credit Suisse, Cayman Island Branch
By:		/s/ Xxxxxx X. Xxxxxxxx
Name:		Xxxxxx X. Xxxxxxxx
Title:		Vice President
By:		/s/ Xxxxx X. Xxxxxxxx
Name:		Xxxxx X. Xxxxxxxx
Title:		Director

GENERAL ELECTRIC CAPITAL CORPORATION
By:		/s/ Xxxxxx X. Xxxxx
Name:		Xxxxxx X. Xxxxx
Title:		Duly Authorized Signatory

GMAC COMMERCIAL FINANCE LLP
By:		/s/ Xxxxxx X. XxXxxxxx
Name:		Xxxxxx X. XxXxxxxx
Title:		Director

JPMORGAN CHASE BANK, N.A.
By:		/s/ Xxxxxx Xxxxxx
Name:		Xxxxxx Xxxxxx
Title:		Vice President

LaSalle Business Credit, LLC
By:		/s/ Xxxxx X. Xxxxxxxxx
Name:		Xxxxx X. Xxxxxxxxx
Title:		Vice President

F-3

Signed as a Deed by the undernoted Attorney of Lloyds TSB Commercial Finance Limited
By:		/s/ Xxxxx Xxxxxxx Xxxxxx
Name:		Xxxxx Xxxxxxx Xxxxxx
Title:		Credit Director
XXXXXXX XXXXX CAPITAL, a Division of Xxxxxxx Xxxxx Business Financial Services Inc.
By:		/s/ Xxxxx Xxxx
Name:		Xxxxx Xxxx
Title:		VP
National City Business Credit, Inc.
By:		/s/ Xxxxxxx X. Xxxxxx
Name:		Xxxxxxx X. Xxxxxx
Title:		Vice President
RZB Finance LLC
By:		/s/ Xxxx X. Xxxxxxx
Name:		Xxxx X. Xxxxxxx
Title:		First Vice President
By:		/s/ Xxxxxxxxx Xxxxx
Name:		Xxxxxxxxx Xxxxx
Title:		Group Vice President
Siemens Financial Services, Inc.
By:		/s/ Xxxxx X. Xxxxxxx
Name:		Xxxxx X. Xxxxxxx
Title:		VP. Credit & Operations, Risk Mgt.

F-4

UBS AG, STAMFORD BRANCH
By:		/s/ Xxxxxxx X. Xxxxxx
Name:		Xxxxxxx X. Xxxxxx
Title:		Director
By:		/s/ Xxxx X. Xxxx
Name:		Xxxx X. Xxxx
Title:		Associate Director

UPS CAPITAL CORPORATION
By:		/s/ Xxxxxxx X’Xxxx
Name:		Xxxxxxx X’Xxxx
Title:		Senior Credit Officer

Wachovia Capital Finance
By:		/s/ X. Xxxxxxx, Xx.
Name:		X. Xxxxxxx, Xx.
Title:		X.X.

Xxxxxxx Business Credit Corporation
By:		/s/ Xxxxxx Xxxxxxx
Name:		Xxxxxx Xxxxxxx
Title:		AVP

Xxxxx Fargo Foothill, LLC
By:		/s/ Xxxxxxx XxXxxxxxx
Name:		Xxxxxxx XxXxxxxxx
Title:		Vice President

F-5