8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

Current Report

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (date of earliest event reported): April 13, 2006

LYONDELL CHEMICAL COMPANY

(Exact name of registrant as specified in its charter)

Delaware

(State or other jurisdiction of incorporation)

1-10145 95-4160558

(Commission File Number) (I.R.S. Employer Identification No.)

1221 McKinney Street, Suite 700, Houston, Texas 77010

(Address of principal executive offices) (Zip Code)

(713) 652-7200

(Registrant's telephone number, including area code)

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

[ ] Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

[ ] Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

[ ] Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

[ ] Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01 Other Events

On April 13, 2006, Millennium Chemicals Inc. ("Millennium"), a wholly owned subsidiary of Lyondell Chemical Company,announced that it has filed an application to voluntarily delist its 4% Senior Convertible Debentures due November 15, 2023 ("Convertible Debentures"), that are currently listed on the New York Stock Exchange and deregister these securities with the Securities and Exchange Commission.  Millennium expects the delisting to be effective in May 2006.  Millennium believes that the withdrawal of the listing and registration of the Convertible Debentures will have a negligible impact on investors. The April 13, 2006 press release regarding the matter is being filed with this Current Report on Form 8-K as Exhibit 99.1.

Item 9.01 Financial Statements and Exhibits

(c) Exhibits.

99.1 Press Release

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

LYONDELL CHEMICAL COMPANY

By:/s/ Kerry A. Galvin

Name: Kerry A. Galvin

Title: Senior Vice President, General Counsel & Secretary

Date: April 13, 2006

INDEX TO EXHIBITS

Exhibit

Number Description

99.1 Press Release

EX-99.1

Exhibit 99.1

For information, contact:

Media -- Lisa M. Martin (713) 309-4890

Investors -- Doug Pike (713) 309-7141

MILLENNIUM ANNOUNCES INTENT TO
DELIST AND DEREGISTER DEBT SECURITIES

HOUSTON, April 13, 2006 -- Millennium Chemicals Inc. announced today that it has filed an application to voluntarily delist its 4% Senior Convertible Debentures due November 15, 2023, that are currently listed on the New York Stock Exchange (NYSE) and to deregister these securities with the Securities and Exchange Commission. The Convertible Debentures are guaranteed by Millennium America Inc., a subsidiary of Millennium. Millennium expects the delisting to be effective in May 2006.

Millennium is no longer required to maintain an effective shelf registration statement with respect to the Convertible Debentures or to maintain the listing of the Convertible Debentures on the NYSE, and the Convertible Debentures have fewer than 15 record holders and extremely low trading volume. Accordingly, Millennium believes that the benefits of listing and registration are outweighed by the administrative burdens and costs. Millennium does not intend to list or register the Convertible Debentures on any other exchange or quotation system.

# # #

Millennium America Inc. is a wholly owned subsidiary of Millennium Chemicals Inc., a major international producer of chemicals including titanium dioxide (TiO2). Millennium Chemicals Inc. is a wholly owned subsidiary of Lyondell Chemical Company (NYSE:LYO).

Source: Millennium Chemicals Inc.; Millennium America Inc.; Lyondell Chemical Company