<PAGE>

                                                                    Exhibit 10.4

                        THIRD AMENDMENT TO SECOND AMENDED
                          AND RESTATED CREDIT AGREEMENT

         This THIRD AMENDMENT TO SECOND AMENDED AND RESTATED CREDIT AGREEMENT
(this "THIRD AMENDMENT") is entered into effective as of February 9, 2004 (the
"AMENDMENT EFFECTIVE DATE"), among GIANT INDUSTRIES, INC., a Delaware
corporation (the "COMPANY"), the financial institutions from time to time
parties to the Credit Agreement (collectively, the "LENDERS"), and BANK OF
AMERICA, N.A. as administrative agent (the "ADMINISTRATIVE AGENT") for the
Lenders and as a Lender and as Letter of Credit Issuing Bank. Capitalized terms
which are used herein without definition and which are defined in the Credit
Agreement referred to below shall have the meanings ascribed to them in the
Credit Agreement.

         WHEREAS, the Company, the Administrative Agent and the Lenders are
parties to that certain Second Amended and Restated Credit Agreement dated as of
May 14, 2002, as amended by the First Amendment dated October 28, 2002 and by
the Second Amendment dated September 30, 2003 (the "CREDIT AGREEMENT"); and

         WHEREAS, the Company desires to modify the Credit Agreement to permit
the Company to enter into a certain crude oil purchase and sale transaction with
Statoil Marketing & Trading (US) Inc. as herein described;

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties hereto hereby agree as
follows:

         SECTION 1. Definitions. Section 1.01 of the Credit Agreement is hereby
amended to add the following definitions:

                  "BARREL" means a volume of forty-two (42) US gallons corrected
         for temperature to sixty (60) degrees Fahrenheit.

                  "STATOIL" means Statoil Marketing & Trading (US) Inc.

                  "STATOIL COMMINGLED INVENTORIES" means the commingled product
         or mass resulting from the commingling (whether by blending, mixing,
         processing or otherwise) of Eligible Refinery Hydrocarbon Inventory
         with crude oil supplied by Statoil and that constitutes Commingled
         Inventories within the meaning of the Statoil Intercreditor Agreement.
         For purposes of calculation of the Borrowing Base, the value of Statoil
         Commingled Inventories shall be equal to the product obtained by
         multiplying (x) the applicable quantities of Statoil Commingled
         Inventories (measured in Barrels in accordance with the Statoil
         Purchase Agreement) by (y) the lowest price per Barrel of the lowest
         priced crude oil (using the lower of cost or market value) included in
         Statoil Commingled Inventories. For purposes of clarity, the "lowest
         price" shall be the absolute lowest figure and not the average of
         applicable prices during the applicable time period.

<PAGE>

                  "STATOIL SEGREGATED INVENTORIES" means crude oil supplied by
         Statoil to Giant Yorktown pursuant to the Statoil Purchase Agreement
         and that constitutes segregated, identifiable Statoil Inventories
         within the meaning of the Statoil Intercreditor Agreement. Statoil
         Segregated Inventories shall at all times be excluded from Eligible
         Refinery Hydrocarbon Inventory for purposes of calculation of the
         Borrowing Base, but may otherwise be included within the Collateral.

                   "STATOIL INTERCREDITOR AGREEMENT" means that certain
         Intercreditor Agreement dated as of February 9, 2004 between Statoil
         and the Administrative Agent.

                  "STATOIL PURCHASE AGREEMENT" means that certain Grane Crude
         Oil Purchase/Sale Agreement 2004/2008 between Statoil and Giant
         Yorktown, as the same may be amended in compliance with the terms of
         this Credit Agreement.

         SECTION 2. Amendment to the Definition of Consolidated Funded
Indebtedness. Clause (a) of the definition of "Consolidated Funded Indebtedness"
in the Credit Agreement is hereby amended to read as follows:

                  "(a) all Indebtedness (other than undrawn or unfunded amounts
         under outstanding Surety Instruments and Indebtedness of the type
         described in CLAUSE (h)(ii) of the definition of Indebtedness, and,
         provided that the Company is in compliance with SECTION 8.21 of this
         Credit Agreement, other than Indebtedness owed to Statoil pursuant to
         the Statoil Purchase Agreement),"

         SECTION 3. Amendment to the Definition of Subordinated Notes. The
definition of "Subordinated Notes" in the Credit Agreement is hereby amended in
its entirety to read as follows:

                  "'SUBORDINATED NOTES' shall mean (i) the BNY $150,000,000
         Subordinated Notes issued under the BNY $150,000,000 Indenture, (ii)
         the BNY $200,000,000 Subordinated Notes issued under the BNY
         $200,000,000 Indenture and (iii) notes issued in refinancing of the BNY
         $150,000,000 Subordinated Notes and/or the BNY $200,000,000
         Subordinated Notes, in whole or in part, whether with the same or
         different noteholders and the same or different indenture trustees,
         provided that such other notes and refinancing notes (or the indenture
         or note purchase agreement, as applicable) (x) contain subordination
         terms at least as favorable to the Lenders as the BNY $150,000,000
         Subordinated Notes and/or the BNY $200,000,000 Subordinated Notes being
         refinanced, and (y) contain other terms no more restrictive on the
         Company and its Subsidiaries than the BNY $150,000,000 Subordinated
         Notes and/or the BNY $200,000,000 Subordinated Notes being refinanced,
         including refinancings thereof. Notes shall not be considered
         `Subordinated Notes' unless and until the Administrative Agent shall
         have received copies of the documentation evidencing or relating to
         such notes evidencing the terms and conditions of subordination
         required hereunder."

                                       2
<PAGE>

         SECTION 4. Amendment to Section 2.07 of the Credit Agreement (Borrowing
Base). Clauses (i), (ii) and (iii) of Section 2.07(a) of the Credit Agreement
are hereby amended in their entirety to read as follows:

                  "(i) eighty percent (80%) of Eligible Refinery Hydrocarbon
         Inventory (except for (A) Eligible Refinery Hydrocarbon Inventory at
         the Company's and its Subsidiaries' service stations and travel
         centers, and (B) Statoil Commingled Inventories), plus (ii) fifty
         percent (50%) of Eligible Refinery Hydrocarbon Inventory at the
         Company's and its Subsidiaries' service stations and travel centers,
         plus (iii) sixty percent (60%) of the Lenders' prorata share of Statoil
         Commingled Inventories (determined in accordance with the Statoil
         Intercreditor Agreement), provided, however, that if the Company shall
         fail to be in compliance with SECTION 7.03(j) or SECTION 8.21 of this
         Credit Agreement, or if Statoil fails to comply with its obligations
         under the Intercreditor Agreement in any material respect, then in any
         such case, 0% of the Statoil Commingled Inventories, plus"

         SECTION 5. Amendment to Section 7.02 of the Credit Agreement
(Recordkeeping for Statoil Supplied Crude Oil). Section 7.02 of the Credit
Agreement is hereby amended by adding new Sections 7.02(h) and (i) to the end
thereof, as follows:

                  "(h) Giant Yorktown shall establish the quantity of Statoil
         Segregated Inventories and Statoil Commingled Inventories on at least a
         weekly basis in accordance with the provisions of Article 14 of the
         Statoil Purchase Agreement with respect to inventory records, and in
         accordance with the procedures and standards for quantity measurement
         set forth in Article 12 of the Statoil Purchase Agreement. Giant
         Yorktown shall furnish the Administrative Agent with copies of all
         audits, reports, statements and information with respect to Statoil
         Inventories required to be provided to Statoil under the Statoil
         Purchase Agreement and any related agreement, as and when such are
         provided to Statoil.

                  "(i) Giant Yorktown's audit and inventory procedures and
         reports shall reflect: (i) the actual volume of crude oil delivered or
         supplied by Statoil; (ii) the volume of Statoil's deemed crude oil
         inventory; and (iii) the ownership and volumes of all persons
         (including Giant Yorktown and its Affiliates) who share commingled
         storage at the Yorktown Refinery for crude oil inventory. Each of the
         foregoing figures shall include tank identification numbers and volumes
         in each tank."

         SECTION 6. Amendment to Section 7.03 of the Credit Agreement (Notices
of Amendments to the Statoil Purchase Agreement). Section 7.03 of the Credit
Agreement is hereby amended by adding a new Section 7.03(j) to the end thereof,
as follows:

                  "(j) of any amendment to the Statoil Purchase Agreement, such
         notice to be given not less than 10 days prior to effective date of
         such amendment, and to be accompanied by a copy of such amendment;"

                                       3
<PAGE>

         SECTION 7. Amendment to Section 7.10(b) of the Credit Agreement
(Inspection of Yorktown Refinery). The Credit Agreement is hereby amended by
adding the following at the end of Section 7.10(b) thereof:

         "Without limitation of the foregoing, representatives of the
         Administrative Agent shall have the right to physically inspect the
         Yorktown Refinery to verify compliance with the terms of the Statoil
         Intercreditor Agreement."

         SECTION 8. Amendment to Section 7.14 (Subordinated Indebtedness). The
first sentence of Section 7.14 of the Credit Agreement is hereby amended to read
as follows:

         "The Company shall maintain not less than $350,000,000 principal amount
         of Subordinated Notes outstanding at all times throughout the term
         hereof; provided, that the Company shall be permitted to have a lesser
         amount outstanding to the extent the Company prepays or redeems
         Subordinated Notes after February 9, 2004 with the proceeds of equity
         offerings."

         SECTION 9. Add New Section 7.17 of the Credit Agreement (Segregation of
Statoil Supplied Crude Oil). The Credit Agreement is hereby amended by adding a
new Section 7.17 thereto, as follows:

                  "7.17 Segregation of Statoil Supplied Crude Oil. To the extent
         feasible and consistent with prudent and safe refinery practices, Giant
         Yorktown shall exercise all commercially reasonable efforts to
         physically segregate Statoil Inventories (as defined in the Statoil
         Intercreditor Agreement) from Eligible Refinery Hydrocarbon Inventory,
         and to physically segregate Eligible Refinery Hydrocarbon Inventory
         from Statoil Inventories, located at the Yorktown Refinery. In the
         event of any commingling of Statoil Inventories and Eligible Refinery
         Hydrocarbon Inventory, then only the Lenders' prorata share of such
         Statoil Commingled Inventories (as determined in accordance with the
         Statoil Intercreditor Agreement) shall be considered Eligible Refinery
         Hydrocarbon Inventory for purposes of calculation of the Borrowing Base
         (provided that such Statoil Commingled Inventories otherwise meet the
         definition of Eligible Refinery Hydrocarbon Inventory."

         SECTION 10. Amendment to Section 8.01 of the Credit Agreement
(Limitation on Liens). A new subsection (i) is hereby added to Section 8.01 of
the Credit Agreement as follows (and existing subsection (i) is renumbered as
subsection (j)):

                   "(i) Liens (including Liens on Collateral to the extent
         provided herein) on crude oil supplied by Statoil pursuant to the
         Statoil Purchase Agreement, securing Indebtedness incurred or assumed
         for the purpose of financing all or any part of the cost of acquiring
         such property after February 9, 2004; provided, that (i) any such Lien
         has attached prior to acquisition of such property or attaches to such
         property concurrently with or within 20 days after the acquisition
         thereof, (ii) such

                                       4
<PAGE>

         Lien attaches solely to the property so acquired in such transaction,
         (iii) the principal amount of the debt secured thereby does not exceed
         100% of the cost of such property, (iv) the principal amount of the
         Indebtedness secured by any and all such purchase money security
         interests in favor of Statoil shall not be increased in excess of the
         amount contemplated by the Statoil Purchase Agreement as in effect on
         February 9, 2004, and (v) such Liens in favor of Statoil shall be
         subject to the terms of an intercreditor agreement between Statoil and
         the Administrative Agent, such intercreditor agreement to be in form
         and substance satisfactory to the Administrative Agent and the Majority
         Lenders; and"

         SECTION 11. Amendment to Section 8.05 of the Credit Agreement
(Limitation on Indebtedness and Contingent Liabilities). Subsection (h) of
Section 8.05 of the Credit Agreement is hereby amended to read as follows:

                  "(h) Indebtedness in respect of purchase money obligations
         within the limitations set forth in SECTIONS 8.01(h) and (i)."

         SECTION 12. Amendment to Section 8.11 of the Credit Agreement
(Subordinated Notes). Section 8.11 of the Credit Agreement is hereby amended in
its entirety to read as follows:

                  "8.11 Subordinated Notes. The Company shall not, and shall not
         permit any Subsidiary to: (a) amend, modify or change, or consent or
         agree to any amendment, modification or change to, any of the terms of
         the Indentures, the Subordinated Notes or the guarantees executed in
         connection therewith, other than (i) any such amendment or modification
         which would extend the maturity or reduce the amount of any payment of
         principal thereof or which would reduce the rate or extend the date of
         payment of interest thereon, (ii) ministerial amendments that do not
         affect the Lenders, including amendments pursuant to Sections 9.01(1)
         through 9.01(5) of the BNY $150,000,000 Indenture and the BNY
         $200,000,000 Indenture, (iii) amendments of any representation or
         warranty, covenant, obligation or default of the Company to any holder
         of Subordinate Notes or to any trustee acting under the Indentures
         (including, without limitation, financial ratios) in a manner which
         either eliminates such representations and warranties, covenants,
         obligations or defaults or renders them less restrictive or onerous
         than those contained in the Subordinate Notes and/or the Indentures as
         in effect on February 9, 2004, and (iv) such other amendments and
         modifications acceptable to the Majority Lenders; or (b) make any
         payments to the holders of the Subordinated Notes or to any trustee
         acting under the Indentures which is prohibited by the Indentures or
         (c) make any prepayment of or redeem in whole or in part the
         Subordinated Notes except with (i) proceeds of refinancing Subordinated
         Notes described in clause (iii) of the definition of `Subordinated
         Notes or (ii) proceeds of equity offerings (or any combination of
         refinancing or equity offerings).'"

         SECTION 13. Add New Section 8.21 to the Credit Agreement (Amendments to
the Statoil Purchase Agreement. A new Section 8.21 is hereby added to the Credit
Agreement as follows:

                                       5
<PAGE>

                  "8.21 Amendments to the Statoil Purchase Agreement; No
         Prepayments. The Company agrees that it shall not amend, and shall not
         permit Giant Yorktown to amend, the Statoil Purchase Agreement in any
         manner that could, in the reasonable opinion of the Administrative
         Agent or the Majority Lenders, adversely affect the Lenders. The
         Company agrees that, so long as no Collateral Event (as defined in the
         Statoil Purchase Agreement) under the Statoil Purchase Agreement has
         occurred and is continuing, it shall not pay, prepay or secure by
         letter of credit, and shall not permit Giant Yorktown to pay for,
         prepay or secure by letter of credit, any crude oil supplied under the
         Statoil Purchase Agreement prior to the time such crude oil is deemed
         to have been Delivered (as defined in the Statoil Purchase Agreement as
         in effect on February 9, 2004) to Giant Yorktown and obligations in
         respect of such crude oil Delivered are due and payable in accordance
         with the terms of the Statoil Purchase Agreement as in effect on
         February 9, 2004. After the occurrence and during the continuance of a
         Collateral Event, the Company and/or Giant Yorktown may prepay or
         secure by letter of credit crude oil supplied under the Statoil
         Purchase Agreement to the extent same is required by the terms of the
         Statoil Purchase Agreement as in effect on February 9, 2004, but the
         Company shall, and shall cause Giant Yorktown to, use commercially
         reasonably efforts to obtain the release by Statoil of all claims to,
         liens on and security interests in all crude oil so prepaid or secured,
         by written release in form and substance reasonably satisfactory to the
         Administrative Agent."

         SECTION 14. Amendment to Section 9.01(e) of the Credit Agreement
(Cross-Default). Section 9.01(e) of the Credit Agreement is hereby amended by
adding a new CLAUSE (IV) to the end thereof, as follows:

                  "(iv) A "Default" or an "Event of Default" shall occur under
         and as defined in the Statoil Purchase Agreement; or"

         SECTION 15. Amendment to Exhibit H to Credit Agreement (Borrowing Base
Certificate). Exhibit H to the Credit Agreement (Borrowing Base Certificate) is
hereby amended to read as set forth in Exhibit H attached hereto.

         SECTION 16. Authority of Administrative Agent to Enter into
Intercreditor Agreement. The Lenders authorize the Administrative Agent to enter
into an Intercreditor Agreement in the form attached as Exhibit A hereto, with
such changes as the Administrative Agent may approve.

         SECTION 17. Representations and Warranties. In order to induce the
Administrative Agent and the Lenders to enter into this Third Amendment, the
Company represents and warrants to the Administrative Agent and to each Lender
that:

         (a) This Third Amendment, the Credit Agreement as amended hereby and
each Loan Document have been duly authorized, executed and delivered by the
Company and

                                       6
<PAGE>

the applicable Loan Parties and constitute their legal, valid and binding
obligations enforceable in accordance with their respective terms (subject, as
to the enforcement of remedies, to applicable bankruptcy, reorganization,
insolvency, moratorium and similar laws affecting creditors' rights generally
and to general principles of equity).

         (b) The representations and warranties set forth in ARTICLE VI of the
Credit Agreement are true and correct in all material respects on and as of the
Amendment Effective Date, after giving effect to, as if made on and as of the
Amendment Effective Date.

         (c) As of the date hereof, at the time of and after giving effect to
this Third Amendment, no Default or Event of Default has occurred and is
continuing.

         (d) No approval, consent, exemption, authorization or other action by,
or notice to, or filing with, any Governmental Authority is necessary or
required in connection with the execution and delivery of this Third Amendment
or the performance by the Company or any Loan Party of its obligations
hereunder. This Third Amendment has been duly authorized by all necessary
corporate action, and the execution, delivery and performance of this Third
Amendment and the documents and transactions contemplated hereby does not and
will not (a) contravene the terms of the Company's or any Loan Party's
Organization Documents; (b) conflict with or result in any breach or
contravention of, or result in or require the imposition or creation of any Lien
under, the Subordinated Notes, the Yorktown Term Loan Documents, as amended, or
any document evidencing any other material Contractual Obligation to which the
Company or any Loan Party is a party or any order, injunction, writ or decree of
any Governmental Authority to which the Company or any Loan Party is subject; or
(c) violate any Requirement of Law.

         (e) The execution, delivery and performance by the Company and Giant
Yorktown of the Statoil Purchase Agreement and the documents and transactions
contemplated hereby (including the Statoil Intercreditor Agreement to the extent
applicable to the Company and Giant Yorktown) does not and will not (a)
contravene the terms of the Company's or any Loan Party's Organization
Documents; (b) conflict with or result in any breach or contravention of, or
result in or require the imposition or creation of any Lien under, the
Subordinated Notes, the Yorktown Term Loan Documents, as amended, or any
document evidencing any other material Contractual Obligation to which the
Company or any Loan Party is a party or any order, injunction, writ or decree of
any Governmental Authority to which the Company or any Loan Party is subject,
other than Liens in favor of Statoil to the extent provided in the Statoil
Purchase Agreement as in effect on February 9, 2004; or (c) violate any
Requirement of Law.

         SECTION 18. Conditions of Effectiveness. The amendments to the Credit
Agreement set forth in SECTIONS 1 through 15 of this Third Amendment shall be
effective on the Amendment Effective Date, provided that the Administrative
Agent shall have received:

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<PAGE>

         (a) counterparts of this Third Amendment duly executed by the Company,
the Loan Parties, the Administrative Agent, and the Majority Lenders;

         (b) counterparts of the Statoil Intercreditor Agreement duly executed
by Statoil and consented to by the Company and Giant Yorktown;

         (c) a copy of the Statoil Purchase Agreement, executed by Statoil and
Giant Yorktown in the same form as previously provided to the Lenders;

         (d) the Company shall have paid the amendment fee described in SECTION
19 of this Third Amendment, and all accrued, unpaid fees, costs and expenses
owed pursuant to this Third Amendment, the Credit Agreement or any other
agreement related thereto, to the extent then due and payable, together with
Attorney Costs of the Administrative Agent to the extent then invoiced prior to
or on the closing date of this Third Amendment; and

         (e) such other documents as the Administrative Agent may require in
connection with the foregoing.

         SECTION 19. Amendment Fee. The Company agrees to pay to the
Administrative Agent for the account of each Lender which timely executes a
counterpart of this Third Amendment, in accordance with its Pro Rata Share, an
amendment fee equal to 0.05% of the total Commitments. Such amendment fee shall
be due and payable in full on the date of execution of this Third Amendment by
the Company and such Lender, shall be fully earned when due and payable, and
shall be in addition to any other fee, cost or expense payable pursuant to the
Credit Agreement.

         SECTION 20. Costs. The Company agrees to pay on demand reasonable
Attorney Costs of the Administrative Agent and all other costs and expenses of
the Administrative Agent, in connection with the preparation, execution and
delivery of this Third Amendment, the Statoil Intercreditor Agreement, and any
other documents executed in connection therewith.

         SECTION 21. Effect of Amendment. This Third Amendment (i) except as
expressly provided herein, shall not be deemed to be a consent to the
modification or waiver of any other term or condition of the Credit Agreement or
of any of the instruments or agreements referred to therein and (ii) shall not
prejudice any right or rights which the Administrative Agent, the Issuing Bank
or the Lenders may now have under or in connection with the Credit Agreement, as
amended by this Third Amendment. Except as otherwise expressly provided by this
Third Amendment, all of the terms, conditions and provisions of the Credit
Agreement shall remain the same. It is declared and agreed by each of the
parties hereto that the Credit Agreement, as amended hereby, shall continue in
full force and effect, and that this Third Amendment and such Credit Agreement
shall be read and construed as one instrument. The Company and each of the other
Loan Parties hereby confirm and agree that all Liens and other security now or
hereafter held by the Administrative Agent for the benefit of the Lenders as
security for

                                       8
<PAGE>

payment of the Obligations are the legal, valid and binding obligations of the
Company and the Loan Parties, remain in full force and effect, are unimpaired by
this Third Amendment, and are hereby ratified and confirmed as security for
payment of the Obligations.

         SECTION 22. Miscellaneous. This Third Amendment shall for all purposes
be construed in accordance with and governed by the laws of the State of New
York and applicable federal law. The captions in this Third Amendment are for
convenience of reference only and shall not define or limit the provisions
hereof. This Third Amendment may be executed in separate counterparts, each of
which when so executed and delivered shall be an original, but all of which
together shall constitute one instrument. In proving this Third Amendment, it
shall not be necessary to produce or account for more than one such counterpart.
This Third Amendment may be delivered by facsimile transmission of the relevant
signature pages hereof.

                         [SIGNATURES BEGIN ON NEXT PAGE]

                                       9
<PAGE>

         THIS IS A SIGNATURE PAGE TO THE GIANT INDUSTRIES, INC. THIRD AMENDMENT
TO SECOND AMENDED AND RESTATED CREDIT AGREEMENT THE CREDIT AGREEMENT (AS AMENDED
BY THIS THIRD AMENDMENT) AND THE OTHER LOAN DOCUMENTS REPRESENT THE FINAL
AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

         THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.

         IN WITNESS WHEREOF, the parties hereto have caused this Third Amendment
to be duly executed and delivered by their proper and duly authorized officers
as of the date and year first above written.

                                            GIANT INDUSTRIES, INC.

                                            By:    /s/ MARK B. COX
                                                -------------------------
                                                 Name:  Mark B. Cox
                                                 Title: CFO

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                  SECOND AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                   BANK OF AMERICA, N.A., as Administrative
                                   Agent, as Letter of Credit Issuing Bank and
                                   as a Lender

                                   By:   /s/ CLAIR M. LIU
                                       ----------------------
                                         Claire M. Liu
                                         Managing Director

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                  SECOND AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                   BANK OF SCOTLAND

                                   By:    /s/ JOSEPH FRATUS
                                       -----------------------
                                        Name:  Joseph Fratus
                                        Title: First Vice President

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                  SECOND AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                   BNP PARIBAS

                                   By:    /s/ MARK A. COX
                                       ---------------------
                                        Name: Mark A. Cox
                                        Title: Director

                                   By:    /s/ GREG SMOTHERS
                                       -----------------------
                                        Name:  Greg Smothers
                                        Title: Vice President

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                  SECOND AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                   COMERICA BANK-CALIFORNIA

                                   By:    /s/ PETER F. FITZPATRICK
                                       ------------------------------
                                        Name:  Peter F. Fitzpatrick
                                        Title: Vice President

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                  SECOND AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                   FLEET NATIONAL BANK

                                   By:    /s/ ALLISON ROSSI
                                       -----------------------
                                        Name:  Allison Rossi
                                        Title: Director

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                  SECOND AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                   HIBERNIA NATIONAL BANK

                                   By:    /s/ NANCY G. MORAGAS
                                      --------------------------
                                       Name:  Nancy G. Moragas
                                       Title: Vice President

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                  SECOND AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                   RZB FINANCE LLC

                                   By:    /s/ JOHN A. VALISKA
                                       -------------------------
                                        Name:  John A. Valiska
                                        Title: Group Vice President

                                   By:    /s/ ELISABETH HIRST
                                       -----------------------------
                                        Name:  Elisabeth Hirst
                                        Title: Assistant Vice President

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                  SECOND AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                   WELLS FARGO BANK, N.A.

                                   By:    /s/ ART KRASNY
                                       --------------------
                                        Name:  Art Krasny
                                        Title: Relationship Manager

    THIS IS A SIGNATURE PAGE TO THE GIANT INDUSTRIES, INC. THIRD AMENDMENT TO
                  SECOND AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                           RATIFICATION AND AGREEMENT

         Each of the undersigned Loan Parties hereby consents to and accepts the
terms and conditions of the foregoing Third Amendment and the transactions
contemplated thereby, agrees to be bound by the terms and conditions thereof,
and ratifies and confirms that each of the Loan Documents to which it is a party
is, and shall remain, in full force and effect after giving effect to the
foregoing Third Amendment.

                                   GIANT INDUSTRIES ARIZONA, INC.,
                                   GIANT FOUR CORNERS, INC.,
                                   DEGUELLE OIL COMPANY,
                                   GIANT MID-CONTINENT, INC.,
                                   GIANT STOP-N-GO OF NEW MEXICO, INC.,
                                   SAN JUAN REFINING COMPANY,
                                   CINIZIA PRODUCTION COMPANY,
                                   PHOENIX FUEL CO., INC.,
                                   GIANT PIPELINE COMPANY, and
                                   GIANT YORKTOWN, INC.
                                   as Loan Parties


                                   By:    /s/ MARK COX
                                      ------------------
                                       Name:  Mark Cox
                                       in each case, as Vice President and Chief
                                       Financial Officer

    THIS IS A SIGNATURE PAGE TO THE GIANT INDUSTRIES, INC. THIRD AMENDMENT TO
                  SECOND AMENDED AND RESTATED CREDIT AGREEMENT

<PAGE>

                                    EXHIBIT H
                             (BORROWING BASE REPORT)
                             GIANT INDUSTRIES, INC.

                                 (See attached)