Exhibit 23
CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
We hereby consent to the incorporation by reference in the Registration Statement on Form S-8 (No. 333-120877) of Lyondell Chemical Company of our report dated June 29, 2005 relating to the financial statements of the Millennium Savings and Investment Plan, which appears in this Form 11-K.
/s/ PricewaterhouseCoopers LLP
PricewaterhouseCoopers LLP
Houston, Texas
June 29, 2005
13