INSTRUMENT ADOPTING LYONDELL CHEMICAL COMPANY ELECTIVE DEFERRAL PLAN FOR NON-EMPLOYEE DIRECTORS

Exhibit 10.41

INSTRUMENT ADOPTING

LYONDELL CHEMICAL COMPANY

ELECTIVE DEFERRAL PLAN

FOR NON-EMPLOYEE DIRECTORS

LYONDELL CHEMICAL COMPANY hereby adopts the Lyondell Chemical Company Elective Deferral Plan for Non-Employee Directors, to read in its entirety as the document entitled “Lyondell Chemical Company Elective Deferral Plan for Non-Employee Directors”, attached hereto.

IN WITNESS WHEREOF, LYONDELL CHEMICAL COMPANY, acting by and through its duly authorized officer, has caused this Instrument to be executed on this 2nd day of December, 2005.

Lyondell Chemical Company

ELECTIVE DEFERRAL PLAN FOR NON-EMPLOYEE DIRECTORS

Effective January 1, 2005

ARTICLE I

GENERAL PROVISIONS

Section 1.1 Purpose and Intent of Plan.

This Plan is intended to provide an opportunity for Directors who are not Company employees to accumulate supplemental funds for retirement or special needs before retirement through the deferral of portions of their Retainer Fee.

This Plan replaces the deferral provisions of the Lyondell Chemical Company Elective Deferral Plan for Non-Employee Directors (“Prior Plan”) to conform to the requirements of Code Section 409A and any related regulation or other guidance promulgated by applicable government agencies (“Code Section 409A”) and establishes the provisions of this Plan to apply to all deferrals of compensation earned or accrued in 2005 and thereafter. Amounts deferred before 2005 and associated earnings shall continue to be governed by the Prior Plan terms.

Section 1.2 Effective Date of Plan.

This Plan document generally shall be effective January 1, 2005, unless certain provisions specify that they are effective on a different date.

Section 1.3 Definitions

(a) Account means a separate bookkeeping account maintained by the Company for each Participant which measures and determines the amounts to be paid to the Participant under the Plan from January 1, 2005 forward. An Account may be divided into subaccounts as needed to reflect particular Deferral Elections.

(b) Administrative Committee means a committee of independent directors designated by the Board.

(c) Beneficiary means a person entitled to receive a Participant’s Plan interest when the Participant’s dies before his Account is totally distributed.

(d) Board means the Board of Directors of Lyondell Chemical Company.

(e) Board Committee means any committee established by the Board which consists of Directors and which reports to the Board.

(f) Chairman Fee means the annual cash amount payable to a Director as additional compensation for serving as Chairman of the Board or as Chairman of a Board Committee.

(g) Change in Control shall be deemed to have occurred on the date that one or more of the following occurs:

(i) Individuals who, within any twelve (12) month period, constitute a majority of the Board ( “Incumbent Directors” ) are replaced as members of the Board by individuals who are not Incumbent Directors. Incumbent Directors shall include any individual becoming a director within the same twelve (12) month period when the person’s election or appointment was approved by a vote of at least a majority of the then Incumbent Directors and shall exclude for this purpose any individual whose initial assumption of office was not endorsed by a majority of the Board,

(ii) The date of any merger, consolidation or recapitalization of the Company (or, if the capital stock of the Company is affected, any subsidiary of the Company), or any sale, lease, or other transfer (in one transaction or a series of transactions contemplated or arranged by any party as a single plan) of all or substantially all of the assets of the Company (each of the foregoing being an “Acquisition Transaction” ) where the shareholders of the Company immediately before that Acquisition Transaction would beneficially own, directly or indirectly, immediately after that Acquisition Transaction, shares or other ownership interests representing in the aggregate less than fifty percent (50%) of (a) the then outstanding common stock or other equity interests of the corporation or other entity surviving or resulting from the merger, consolidation or recapitalization or acquiring assets of the Company, as the case may be, or of its ultimate parent corporation or other entity, if any (in either case, the “Surviving Entity” ), and (b) the Combined Voting Power of the then outstanding Voting Securities of the Surviving Entity; or

(iii) Any Person shall be or become the beneficial owner (as defined in Rules 13d-3 and 13d-5 under the Securities Exchange Act of 1934, as amended), directly or indirectly, of securities of the Company representing in the aggregate more than fifty percent (50%) of either (A) the then outstanding shares of common stock of the Company ( “Common Shares” ) or (B) the Combined Voting Power of all then outstanding Voting Securities of the Company; provided , however , that notwithstanding the foregoing, a Change in Control shall not be deemed to have occurred for purposes of this Subsection (iii):

(1) Solely as a result of an acquisition of securities by the Company which, by reducing the number of Common Shares or other Voting Securities outstanding, increases (a) the proportionate number of Common Shares beneficially owned by any Person to more than fifty percent (50%) of the Common Shares then outstanding, or (b) the proportionate voting power represented by the Voting Securities beneficially owned by any Person to more than fifty percent (50%) of the Combined Voting Power of all then outstanding Voting Securities;

(2) Solely as a result of an acquisition of securities directly from the Company, except for any conversion of a security that was not acquired directly from the Company;

(iv) For purposes of this Change in Control definition, the following capitalized terms have the following meanings:

2

(1) “Affiliate” shall mean, as to a specified person, another person that directly, or indirectly through one or more intermediaries, controls or is controlled by, or is under common control with, the specified person, within the meaning of such terms as used in Rule 405 under the Securities Act of 1933, as amended, or any successor rule.

(2) “Combined Voting Power” shall mean the aggregate votes entitled to be cast generally in the election of the Board of Directors, or similar managing group, of a corporation or other entity by holders of then outstanding Voting Securities of such corporation or other entity.

(3) “Person” shall mean any individual, entity (including, without limit, any corporation, partnership, trust, joint venture, association or governmental body) or group (as defined in Sections 14(d)(3) or 15(d)(2) of the Exchange Act and the rules and regulations thereunder); provided , however , that Person shall not include the Company, any of its subsidiaries or affiliates or LYONDELL-CITGO Refining LP (“LCR”), any employee benefit plan of the Company or LCR or any of their subsidiaries or any entity organized, appointed or established by the Company, LCR, or their subsidiaries for or pursuant to the terms of any plan.

(4) “Voting Securities” shall mean all securities of a corporation or other entity having the right under ordinary circumstances to vote in an election of the Board of Directors, or similar managing group, of such corporation or other entity.

(h) Code means the Internal Revenue Code of 1986, as amended, including any successor provisions and any regulations or other guidance promulgated by applicable government agencies.

(i) Common Stock means the Company’s common stock, par value $1.00 per share.

(j) Company means Lyondell Chemical Company, a Delaware corporation, or its successor.

(k) Deferral Election means a Director’s election to defer Retainer Fees during a Deferral Period according to Section 2.1.

(l) Deferral Period means the particular calendar year for which a Deferral Election is made. A new Deferral Period begins each January 1 and ends each December 31, but for a new Director, his or her initial Deferral Period shall commence thirty (30) days after the Director’s election to the Board.

(m) Deferred Compensation means the aggregate amount of Retainer Fees a Director elects to defer and DSUs credited to the Participant’s Account.

3

(n) Deferred Stock Units or DSUs means a bookkeeping unit representing the value of one share of Common Stock used to credit certain deferrals to a Participant’s account and track investment returns.

(o) Director means a Director of the Board who is not a current employee of the Company or any of its subsidiaries or affiliates.

(p) Distribution means a distribution of a Participant’s Account as a result of Termination of Service or other event specified under this Plan and permitted by Code Section 409A.

(q) Effective Date means January 1, 2005.

(r) Financial Hardship means a condition of severe financial difficulty, due to an unforeseeable emergency resulting from (i) an illness or accident of the Participant, his spouse or dependent; (ii) a casualty causing a Participant’s property loss; or (iii) other similar or extraordinary and unforeseeable circumstances created by events beyond the Participant’s control, as determined by the Administrative Committee, upon advice of counsel, based on written information supplied by the Participant and which is sufficient, in counsel’s judgment, to justify a change in a Plan distribution election without causing the Participant or any other Plan Participant to receive taxable income from the Plan before the Participant actually receives his or her benefit.

(s) In-Service Distribution means a distribution before Termination of Service as specified in Section 4.4 and permitted by Code Section 409A.

(t) Interest Rate means (i) prior to January 1, 2006, 125 percent of the rolling average Ten-Year Treasury Note Rate, on October 1 before the applicable Plan Year begins, and (ii) for each Plan Year commencing on or after January 1, 2006, the previous monthly average of the closing yield to maturity, as reported by Bloomberg, of Lyondell Chemical Company’s most junior publicly traded debt on December 1 of the prior Plan Year. If this debt is retired during the Plan Year, the monthly interest rate shall be based on the previous monthly average of the then longest maturity for the Company’s most junior publicly traded debt.

(u) Participant means any Director participating in this Plan under Article II, or any former Director who has not received the entire Plan benefit to which he or she is entitled.

(v) Plan means this Elective Deferral Plan for Non-Employee Directors.

(w) Plan Year means each calendar year beginning on January 1 and ending on December 31.

(x) Retainer Fee means the annual amount paid in cash to a Director as compensation for serving in that capacity and any additional Chairman Fees.

(y) Survivor Benefit means the benefits described in Section 4.3 provided when a Participant dies before his or her Account is distributed.

4

(z) Termination of Service means the Director ceasing to be a Board member, which complies with the requirements of Code Section 409A.

(aa) Trust Agreement means the Lyondell Chemical Company Non-Employee Directors Benefit Plans Trust Agreement and any amendments or successor agreements.

(bb) Valuation Date means the last day of each month, or other dates Administrative Committee determines in its discretion, which may be either more or less frequent, used to value Participants’ Accounts.

5

ARTICLE II

PARTICIPATION AND DEFERRAL ELECTIONS

Section 2.1 Elective Deferrals.

A Director may elect to defer Retainer Fees and specify the desired form of crediting method under Section 3.5 before a Deferral Period begins by submitting a Deferral Election for the Deferral Period. The time and form or distribution of the amount deferred shall be elected at the time the Deferral Election is made. Each Director’s Deferral Election shall be irrevocable after the Deferral Period begins. A Participant may also elect to defer an In-Service Distribution as provided in Section 4.4.

Section 2.2 Deferral Limits.

Deferral Elections shall be subject to the following limits:

(a) A Participant must defer a minimum deferral amount reasonably anticipated to exceed Eight Thousand Dollars ($8,000) per Deferral Period.

(b) A Participant may not defer an amount exceeding one hundred (100%) of the Participant’s Retainer Fee that would otherwise be payable in cash for that Deferral Period.

Section 2.3 Termination of Service.

Any outstanding Deferral Election shall terminate on the Participant’s Termination of Service.

Section 2.4 Modification of Deferral Elections.

The Administrative Committee may permit a Participant to cease the remaining deferrals under a Deferral Election, if it finds that the Participant has suffered a Financial Hardship, to the extent that the Deferral Election may be revoked as a result of Financial Hardship under Code Section 409A.

6

ARTICLE III

DEFERRED COMPENSATION ACCOUNTS

Section 3.1 Accounts.

Accounts shall be maintained for each Participant for record-keeping purposes only. A Participant’s Account may be divided into subaccounts if necessary to determine how a Participant’s Distribution Elections shall apply to portions of the Account.

Section 3.2 Deferred Compensation.

A Participant’s Deferred Compensation shall be credited to the Participant’s Account on the date when the corresponding non-deferred portion of compensation is paid or would have been paid but for the Deferral Election.

(a) New Directors. A person who becomes a Director after January 1 of a Plan Year shall be eligible to make a Deferral Election within thirty (30) days of the date he becomes a Director for the pro-rated Retainer Fee payable for service during that Plan Year.

(b) Tax Withholding . The Company shall have the right to withhold from any Retainer Fees or Plan benefits (or otherwise cause the Director, his Beneficiary or the executor or administrator of his estate to pay) any federal, state, local or foreign taxes required to be withheld for any Deferred Compensation or benefits paid by the Plan, including, but not limited to, Medicare taxes.

Section 3.3 Deferred Stock Units.

(a) DSU Valuation . DSUs allocated to a Participant’s Account during a Plan Year for any reason other than a dividend payment, and DSUs transferred into the cash portion of a Participant’s Account according to a crediting method election change under Section 3.5, shall be valued at the closing price per share of Common Stock on the last trading date of the prior Plan Year.

(b) Dividends . When dividends are paid on shares of Common Stock, a Participant’s Account which has been credited with DSUs also shall be credited on the dividend record date with an additional number of DSUs equal to (A) the total amount of dividends payable for the number of shares of Common Stock represented by the DSUs credited to the Participa