<PAGE>
                                                                    EXHIBIT 10.1

                                                                       EXECUTION

                                 FIRST AMENDMENT
                               TO CREDIT AGREEMENT


                  This FIRST AMENDMENT TO CREDIT AGREEMENT (this "AMENDMENT") is
dated as of December 15, 2004 and entered into by and among COVANTA ENERGY
CORPORATION, a Delaware corporation ("COMPANY"), and THE SUBSIDIARIES OF COMPANY
LISTED ON THE SIGNATURE PAGES HEREOF AS BORROWERS (collectively, Company and
such Subsidiaries of Company are "BORROWERS" and each a "BORROWER"), THE LENDERS
PARTY HERETO, BANK OF AMERICA, N.A., as Administrative Agent for the Lenders
("ADMINISTRATIVE AGENT"), and DEUTSCHE BANK SECURITIES, INC., as Documentation
Agent for the Lenders ("DOCUMENTATION AGENT"), and is made with reference to
that certain Credit Agreement dated as of March 10, 2004 by and among Borrowers,
the financial institutions parties thereto as Lenders, Documentation Agent and
Administrative Agent (the "CREDIT AGREEMENT"). Capitalized terms used herein
without definition shall have the same meanings herein as set forth in the
Credit Agreement (as amended by this Amendment).


                                    RECITALS

                  WHEREAS, Borrowers and the undersigned Lenders desire (i) to
amend the Credit Agreement to permit the termination, sale and/or assignment of
the obligations relating to certain landfill gas Projects of Covanta Power
Pacific, Inc., Pacific Recovery Corporation and 8309 Tujunga Avenue Corporation,
to permit the assignment of the contracts relating to the wastewater treatment
facility with the Village of Canastota, New York, and to permit the separation
of Mt. Lassen and Burney Mountain wood plant Projects and the permit for the
Three Mountain Power Project from the other wood plant Projects of Company and
its Subsidiaries, and (ii) to make certain other amendments to the Credit
Agreement, subject to the terms and conditions set forth below;

                  NOW, THEREFORE, in consideration of the premises and
agreements, provisions and covenants herein contained, the parties hereto agree
as follows:

         SECTION 1. AMENDMENTS TO THE CREDIT AGREEMENT

         1.1 PROVISIONS RELATING TO DOCUMENTATION AGENT.

                  The introductory paragraph of the Credit Agreement is hereby
amended by deleting the reference to "DEUTSCHE BANK SECURITIES, INC." and
substituting therefor "DEUTSCHE BANK AG, NEW YORK BRANCH".

         1.2 PROVISIONS RELATING TO DEFINED TERMS.

                  Subsection 1.1 of the Credit Agreement is hereby amended by
inserting the following new definitions in the appropriate alphabetical order:




<PAGE>


                  "CANASTOTA PROJECT" means the wastewater treatment facility
         for the Village of Canastota, New York.

                  "CANASTOTA PROJECT AGREEMENT" means the Operation and
         Maintenance of the Village of Canastota Wastewater Treatment Facility
         Agreement, dated June 1998, between the Village of Canastota and CES,
         as in effect immediately prior to the First Amendment Effective Date.

                  "CPPI" means Covanta Power Pacific, Inc., a Delaware
         corporation.

                  "CES" means Covanta Cunningham Environmental Support, Inc.

                  "FIRST AMENDMENT" means the First Amendment to Credit
         Agreement by and among Borrowers, Agents and Lenders, dated as of
         December 15, 2004.

                  "FIRST AMENDMENT EFFECTIVE DATE" has the meaning assigned to
         that term in Section 2 of the First Amendment.

                  "GRRP" means Generating Resource Recovery Partners, L.P., a
         California limited partnership.

                  "GUDE PROJECT" means the landfill gas Project in Montgomery
         County, Maryland.

                  "GUDE PROJECT AGREEMENTS" means, collectively, each of the
         agreements set forth on Exhibit A to the First Amendment, as in effect
         immediately prior to the First Amendment Effective Date.

                  "INACTIVE FOREIGN SUBSIDIARY" and "INACTIVE FOREIGN
         SUBSIDIARIES" have the meanings assigned to those terms in Section 8.

                  "PENROSE PROJECT" means the landfill gas Project in Sun
         Valley, California.

                  "PENROSE PROJECT AGREEMENTS" means, collectively, each of the
         agreements set forth on Exhibit B to the First Amendment, as in effect
         immediately prior to the First Amendment Effective Date.

                  "PEOG" means Pacific Energy Operating Group, L.P., a
         California limited partnership.

                  "PEOG/GRRP PURCHASE" means the purchase by CPPI (or a
         Subsidiary of CPPI that is a Borrower) from Pierpoint Power, Inc. of
         all of the outstanding limited partnership interests in PEOG and GRRP
         for cash consideration in the aggregate amount of $10.00 pursuant to
         documentation in form and substance satisfactory to Agents.

                  "PERI" means Pacific Energy Resources Incorporated, a
         California corporation.

                  "SANTA CLARA PROJECT" means the landfill gas Project in Santa
         Clara, California.


                                       2
<PAGE>

                  "SANTA CLARA PROJECT AGREEMENTS" means, collectively, each of
         the agreements set forth on Exhibit C to the First Amendment, as in
         effect immediately prior to the First Amendment Effective Date.

                  "TOYON PROJECT" means the landfill gas Project in Los Angeles,
         California.

                  "TOYON PROJECT AGREEMENTS" means, collectively, each of the
         agreements set forth on Exhibit D to the First Amendment, as in effect
         immediately prior to the First Amendment Effective Date.

                  "TUJUNGA" means 8309 Tujunga Avenue Corporation, a California
         corporation.

         1.3 PROVISIONS RELATING TO REPRESENTATIONS AND WARRANTIES.

                  Section 5 of the Credit Agreement is hereby amended by adding
at the end thereof a new subsection 5.24 as follows:

                  "5.24 INACTIVE FOREIGN SUBSIDIARIES. None of the Inactive
         Foreign Subsidiaries has any material assets or operations. Borrowers
         have commenced dissolution proceedings with respect to the Inactive
         Foreign Subsidiaries."

         1.4 PROVISIONS RELATING TO NEGATIVE COVENANTS.

                  A. Subsection 7.3 of the Credit Agreement is hereby amended by
(i) deleting the "and" at the end of paragraph (xiii) thereof, (ii) deleting the
"." at the end of paragraph (xiv) thereof and substituting therefor "; and", and
(iii) adding at the end thereof the following new paragraph (xv):

                  "(xv) CPPI (or a Subsidiary of CPPI that is a Borrower) may
         consummate the PEOG/GRRP Purchase and own Investments in all of the
         outstanding limited partnership interests in PEOG and GRRP, so long as
         (i) on and after consummation of the PEOG/GRRP Purchase all of the
         outstanding limited partnership interests in PEOG and GRRP shall be
         owned by CPPI (or a Subsidiary of CPPI that is a Borrower), (ii) upon
         consummation of the PEOG/GRRP Purchase, Collateral Agent shall be
         granted a First Priority perfected Lien in such limited partnership
         interests, and each Credit Party shall have executed such documents and
         taken such actions as may be required by the Credit Documents in
         connection therewith, (iii) immediately after giving effect to thereto,
         the PEOG/GRRP Purchase will not expand or modify the existing
         obligations of CPPI or any of its Subsidiaries to PEOG or GRRP and will
         not give rise to any obligations on the part of CPPI or any of its
         Subsidiaries to make capital contributions in respect of the limited
         partnership interests in PEOG and GRRP held by it and (iv) upon
         consummation of the PEOG/GRRP Purchase, Agents shall have received
         written acknowledgement in form and substance satisfactory to Agents
         from Company and its Subsidiaries with respect to the matters described
         in clause (iii) hereof.".

                  B. Subsection 7.6C of the Credit Agreement is hereby amended
and restated in its entirety as follows:


                                       3
<PAGE>


                  "C. MINIMUM CONSOLIDATED NET WORTH. Company shall not permit
         Consolidated Net Worth as at any date on or after the end of the most
         recently ended Fiscal Quarter set forth in the table below to be less
         than the correlative amount indicated:

<Table>
<Caption>
                                 FISCAL QUARTER                           MINIMUM CONSOLIDATED NET WORTH
                                 --------------                           ------------------------------
<S>                                                                      <C>
                                    FQ4 2004                                        $46,017,000
                                    FQ1 2005                                        $47,574,000
                                    FQ2 2005                                        $49,130,000
                                    FQ3 2005                                        $50,687,000
                                    FQ4 2005                                        $52,243,000
                                    FQ1 2006                                        $57,508,000
                                    FQ2 2006                                        $59,508,000
                                    FQ3 2006                                        $63,508,000
                                    FQ4 2006                                        $67,908,000
                                    FQ1 2007                                        $70,908,000
                                    FQ2 2007                                        $73,908,000
                                    FQ3 2007                                        $77,908,000
                                    FQ4 2007                                        $82,724,000
                                    FQ1 2008                                        $84,724,000
                                    FQ2 2008                                        $86,724,000
                                    FQ3 2008                                        $89,724,000
                            FQ4 2008 and thereafter                                 $94,146,000
</Table>


                  C. Subsection 7.7 of the Credit Agreement is hereby amended by
(i) deleting the "and" at the end of paragraph (iii) thereof, (ii) deleting the
"." at the end of paragraph (iv) thereof and substituting therefor "; and", and
(iii) adding at the end thereof the following:

                  "(v) PERI may transfer to CPPI all of the outstanding Capital
         Stock of Pacific Ultrapower Chinese Station held by PERI on the First
         Amendment Effective Date, so long as (a) such transfer occurs on or
         prior to March 31, 2005, (b) upon such transfer, Collateral Agent shall
         be granted a First Priority perfected Lien in such Capital Stock, and
         each Credit Party shall have executed such documents and taken such
         actions as may be required by the Credit Documents in connection
         therewith, (c) such transfer shall not give rise to any additional
         obligations of any Borrower other than under this Agreement and the
         Credit Documents and other than tax obligations not exceeding $35,000
         arising directly in connection with such transfer, and (d) on or prior
         to the date of such transfer,



                                       4
<PAGE>

         Agents shall have received an Officer's Certificate in form and
         substance satisfactory to Agents from Company and its Subsidiaries
         certifying as to the matters described in clauses (b) and (c).

         Notwithstanding any provision of this Agreement that would otherwise
         permit the following, CES may assign all of its rights and obligations
         under the Canastota Project Agreement to a third party, only if (a)
         such assignment occurs on or prior to December 31, 2004, (b) after
         giving effect to such assignment, Borrowers and each of their
         respective Subsidiaries have no outstanding or further obligations
         under or arising out of the Canastota Project Agreement, under any
         guaranty or otherwise, (c) on or prior to the date of such assignment,
         each of the Village of Canastota and the assignee of Canastota Project
         Agreement shall have acknowledged in writing that it releases any
         claims against CES, Borrowers and any of their respective Subsidiaries
         arising out of or relating to the Canastota Project Agreement, and (d)
         on or prior to the date of such assignment, Agents shall have received
         an Officer's Certificate in form and substance satisfactory to Agents
         from Company certifying as to the matters described in clauses (b) and
         (c).

         Notwithstanding any provision of this Agreement that would otherwise
         permit the following, CPPI, PEOG and Tujunga may assign all of their
         rights and obligations under the Penrose Project Agreements and the
         Toyon Project Agreements to Penrose Landfill Gas Conversion, LLC and
         Toyon Landfill Gas Conversion, LLC, respectively, and Penrose Landfill
         Gas Conversion, LLC and Toyon Landfill Gas Conversion, LLC may assign
         and/or sell all of their rights and obligations under the Penrose
         Project Agreements and the Toyon Project Agreements, respectively, to a
         third party, in each case only if (a) each such assignment or sale
         occurs on or prior to March 31, 2005, (b) after giving effect to any
         assignment or sale of the Penrose Project Agreements to a third party,
         Borrowers and each of their respective Subsidiaries have no outstanding
         or further obligations under or arising out of the Penrose Project
         Agreements, under any guaranty or otherwise, (c) after giving effect to
         any assignment or sale of the Toyon Project Agreements to a third
         party, Borrowers and each of their respective Subsidiaries have no
         outstanding or further obligations under or arising out of the Toyon
         Project Agreements, under any guaranty or otherwise (other than under
         an agreement with respect to the provision of transitional operations
         and maintenance services on terms and conditions and pursuant to
         documentation in form and substance satisfactory to Agents), and (d) on
         or prior to the date of any assignment or sale of the Penrose Project
         Agreements or the Toyon Project Agreements to a third party, Agents
         shall have received an Officer's Certificate in form and substance
         satisfactory to Agents from Company certifying as to the matters
         described in clause (b) or clause (c), respectively.".

                  1.5 PROVISIONS RELATING TO EVENTS OF DEFAULT.

                  A. Subsection 8.14 of the Credit Agreement is hereby amended
by adding immediately prior to the ";" at the end thereof the following new
provisos:

         "; provided, however, that termination by Company and its Subsidiaries
         of any of the Gude Project Agreements, the Penrose Project Agreements,
         the Santa Clara Project Agreements and the Toyon Project Agreements
         shall not constitute an Event of Default




                                       5
<PAGE>

         under this subsection 8.14, so long as, in each case, (i) such
         termination is in connection with a sale or closure of the relevant
         Project that is not prohibited under this Agreement, (ii) such
         termination occurs on or prior to March 31, 2005, (iii) on or prior to
         the date of such termination, Agents shall have received an Officer's
         Certificate in form and substance satisfactory to Agents from Company
         acknowledging that such termination will not give rise to any
         obligations (or accelerate or cause to mature any existing payment
         obligations) on the part of any Borrower under any guaranty or
         otherwise, (iv) such termination is pursuant to the contractual right
         of termination in such agreements or the mutual agreement of the
         parties thereto, and (v) Company and its Subsidiaries exercise best
         efforts after such termination to collect any applicable termination
         penalty or other obligations owed to Company or any of its Subsidiaries
         by the counterparty to such agreements".

                  B. Section 8 of the Credit Agreement is hereby amended by
adding at the end thereof (immediately before Section 9 of the Credit Agreement)
the following:

                  "Notwithstanding anything in the Credit Agreement or the other
         Credit Documents to the contrary, so long as OPI Carmona Limited, a
         company organized under the laws of the Cayman Islands, OPI Carmona One
         Limited, a company organized under the laws of the Cayman Islands, or
         Covanta Energy Europe, Inc., a company organized under the laws of the
         United Kingdom (each, an "INACTIVE FOREIGN SUBSIDIARY", and
         collectively, the "INACTIVE FOREIGN SUBSIDIARIES"), has no material
         assets or operations, (i) Borrowers shall not be required to deliver
         certificates representing the Capital Stock of such Inactive Foreign
         Subsidiary (or any endorsement or instrument of transfer or assignment
         with respect thereto) to Collateral Agent and (ii) the failure of
         Borrowers to deliver any such certificate, endorsement or instrument
         shall not be deemed a breach of subsection 5.15A of this Agreement or
         Section 4(f) or 9(a) of the Security Agreement. Each Borrower hereby
         agrees to use commercially reasonable efforts to complete the 'winding
         down' and dissolution of the Inactive Foreign Subsidiaries as soon as
         practicable after the First Amendment Effective Date in accordance with
         any applicable law, statute, rule or regulation. Each Borrower further
         agrees that prior to the completion of such 'winding down' and
         dissolution, such Inactive Foreign Subsidiaries shall conduct no
         business other than in connection with their 'winding down' and
         dissolution."

         1.6 SCHEDULES.

                  Schedules 7.4(iv) and 7.4(vi) of the Credit Agreement are
hereby amended by deleting them in their entirety and substituting in place
thereof new Schedules 7.4(iv) and 7.4(vi) in the form of such Schedules set
forth on Annex A to this Amendment.

         SECTION 2. CONDITIONS TO EFFECTIVENESS

                  Section 1 of this Amendment shall only become effective upon
the first date on which all of the following conditions precedent shall have
been satisfied (the date of satisfaction of such conditions being referred to
herein as the "FIRST AMENDMENT EFFECTIVE DATE"):


                                       6
<PAGE>
         2.1 SUCCESSOR DOCUMENTATION AGENT. Deutsche Bank AG, New York Branch,
in its capacity as successor Documentation Agent, shall have executed a
counterpart hereof.

         2.2 NEW L/C FACILITY AGREEMENT AMENDMENT. Agents shall have received a
fully executed amendment to the New L/C Facility Agreement executed by
"Requisite Lenders" thereunder, on terms and conditions substantially identical
to the terms and conditions of this Amendment and pursuant to documentation in
form and substance satisfactory to Agents, the conditions precedent to the
effectiveness of each of the provisions of which shall have been satisfied.

         2.3 PAYMENT OF EXPENSES. Borrowers shall have paid in full all
outstanding statements for fees and expenses of O'Melveny & Myers LLP, to the
extent submitted to Company prior to 12:00 Noon (New York City time) on December
14, 2004.

         2.4 AMENDMENT FEE. Borrowers shall have paid to Administrative Agent,
for distribution to Lenders that have executed and delivered a counterpart to
this Amendment prior to 12:00 Noon (New York City time) on December 15, 2004
ratably according to their relative Letter of Credit Exposure, an amendment fee
equal to .15% of the aggregate Letter of Credit Exposure of all Lenders on and
as of such date, and after giving effect to the payment of such fees Borrowers
shall be in compliance with subsection 6.13 of the Amended Agreement (as
hereinafter defined).

         2.5 AGENTS' FEES. Company shall have paid to Agents such fees in the
amounts separately agreed upon between Company and Agents.

         2.6 NEW BORROWERS. Borrowers shall have executed and delivered all
documents and instruments and taken all actions required under subsections 6.8A
and 6.8B of the Credit Agreement with respect to Penrose Landfill Gas
Conversion, LLC and Toyon Landfill Gas Conversion, LLC as if such entities were
Additional Subsidiary Borrowers, and CPPI shall have executed and delivered all
documents and instruments and taken all actions required under the Security
Agreement and the other Credit Documents with respect to its membership
interests in Penrose Landfill Gas Conversion, LLC and Toyon Landfill Gas
Conversion, LLC.

         2.7 ACKNOWLEDGMENT AND CONSENT. Agents shall have received a fully
executed Acknowledgment and Consent to this Amendment executed by DHC, pursuant
to documentation in form and substance satisfactory to Agents.

         SECTION 3. BORROWERS' REPRESENTATIONS AND WARRANTIES

                  In order to induce the Lenders to enter into this Amendment
and to amend the Credit Agreement in the manner provided herein, Borrowers
represent and warrant to each Lender that the following statements are true,
correct and complete:

         3.1 CORPORATE POWER AND AUTHORITY. Each Credit Party that is party
thereto has all requisite corporate power and authority to enter into this
Amendment and to carry out the transactions contemplated by, and perform its
obligations under, the Credit Agreement as amended by this Amendment
(collectively, the "AMENDED AGREEMENT").



                                       7
<PAGE>

         3.2 AUTHORIZATION OF AGREEMENTS. The execution and delivery of this
Amendment have been duly authorized by all necessary corporate action on the
part of each Credit Party that is party thereto and the performance of this
Amendment and the Amended Agreement has been duly authorized by all necessary
corporate action on the part of each Credit Party that is party thereto.

         3.3 NO CONFLICT. The execution and delivery by each Credit Party that
is party to this Amendment and the performance by each Borrower of this
Amendment and the Amended Agreement do not and will not (i) violate any
provision of any law or any governmental rule or regulation applicable to
Company or any of its Subsidiaries, the Organizational Documents of Company or
any of its Subsidiaries or any order, judgment or decree of any court or other
Government Authority binding on Company or any of its Subsidiaries, (ii)
conflict with, result in a breach of or constitute (with due notice or lapse of
time or both) a default under any Contractual Obligation of Company or any of
its Subsidiaries, (iii) result in or require the creation or imposition of any
Lien upon any of the properties or assets of Company or any of its Subsidiaries,
or (iv) require any approval of stockholders or any approval or consent of any
Person under any Contractual Obligation of Company or any of its Subsidiaries.

         3.4 GOVERNMENTAL CONSENTS. The execution and delivery by each Credit
Party that is party to this Amendment and the performance by each Borrower of
this Amendment and the Amended Agreement do not and will not require any
Governmental Authorization.

         3.5 BINDING OBLIGATION. This Amendment has been duly executed and
delivered by each Credit Party that is party thereto, and each of this Amendment
and the Amended Agreement is the legally valid and binding obligation of each
Credit Party enforceable against each Credit Party in accordance with its
respective terms, except as may be limited by bankruptcy, insolvency,
reorganization, moratorium or similar laws relating to or limiting creditors'
rights generally or by equitable principles relating to enforceability.

         3.6 INCORPORATION OF REPRESENTATIONS AND WARRANTIES FROM CREDIT
AGREEMENT. The representations and warranties contained in Section 5 of the
Amended Agreement are and will be true, correct and complete in all material
respects on and as of the First Amendment Effective Date to the same extent as
though made on and as of that date, except to the extent such representations
and warranties specifically relate to an earlier date, in which case they were
true, correct and complete in all material respects on and as of such earlier
date.

         3.7 ABSENCE OF DEFAULT. As of the date hereof after giving effect
hereto, there exists no Event of Default or Potential Event of Default under the
Credit Agreement.

         SECTION 4. ACKNOWLEDGEMENT AND CONSENT

                  Each Borrower hereby acknowledges that it has read this
Amendment and consents to the terms hereof and further hereby confirms and
agrees that, notwithstanding the effectiveness of this Amendment, the
obligations of such Credit Party under each of the Credit Documents to which
such Credit Party is a party shall not be impaired and each of the Credit
Documents to which such Credit Party is a party are, and shall continue to be,
in full force and effect and are hereby confirmed and ratified in all respects.



                                       8
<PAGE>

         SECTION 5. DISTRIBUTION OF EXCESS DISTRIBUTABLE CASH.

                  Each Borrower hereby agrees that on or before February 15,
2005, Borrower shall designate not less than $5,000,000 as "Excess Distributable
Cash" under the Approved Plan of Reorganization, which "Excess Distributable
Cash" shall be distributed on or before such date in accordance with the
Approved Plan of Reorganization.

         SECTION 6. MISCELLANEOUS

         6.1      REFERENCE TO AND EFFECT ON THE CREDIT AGREEMENT AND THE OTHER
                  CREDIT DOCUMENTS.

                  A. On and after the First Amendment Effective Date, each
reference in the Credit Agreement to "this Agreement", "hereunder", "hereof",
"herein" or words of like import referring to the Credit Agreement, and each
reference in the other Credit Documents to the "Credit Agreement", "thereunder",
"thereof" or words of like import referring to the Credit Agreement shall mean
and be a reference to the Credit Agreement as amended by this Amendment.

                  B. Except as specifically amended by this Amendment, the
Credit Agreement and the other Credit Documents shall remain in full force and
effect and are hereby ratified and confirmed.

                  C. The execution, delivery and performance of this Amendment
shall not constitute a waiver of any provision of, or operate as a waiver of any
right, power or remedy of any Agent or any Lender under, the Credit Agreement or
any of the other Credit Documents.

         6.2 FEES AND EXPENSES. Each Borrower acknowledges that all costs, fees
and expenses as described in subsection 10.2 of the Credit Agreement incurred by
Administrative Agent, Documentation Agent or the Lenders and counsel to the
Agents with respect to this Amendment and the documents and transactions
contemplated hereby shall be for the account of Borrowers.

         6.3 HEADINGS. Section and subsection headings in this Amendment are
included herein for convenience of reference only and shall not constitute a
part of this Amendment for any other purpose or be given any substantive effect.

         6.4 APPLICABLE LAW. THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF
THE PARTIES HEREUNDER SHALL BE GOVERNED BY, AND SHALL BE CONSTRUED AND ENFORCED
IN ACCORDANCE WITH, THE INTERNAL LAWS OF THE STATE OF NEW YORK (INCLUDING
WITHOUT LIMITATION SECTION 5-1401 OF THE GENERAL OBLIGATIONS LAW OF THE STATE OF
NEW YORK), WITHOUT REGARD TO CONFLICTS OF LAWS PRINCIPLES.

         6.5 COUNTERPARTS; EFFECTIVENESS. This Amendment may be executed in any
number of counterparts and by different parties hereto in separate counterparts,
each of which when so executed and delivered shall be deemed an original, but
all such counterparts together shall constitute but one and the same instrument;
signature pages may be detached from multiple




                                       9
<PAGE>

separate counterparts and attached to a single counterpart so that all signature
pages are physically attached to the same document.

                  Executed counterparts hereof may be delivered by
telefacsimile. The effectiveness of any such signatures shall, subject to
applicable law, have the same force and effect as an original copy with manual
signatures and shall be binding on all Credit Parties, Agents and Lenders.
Administrative Agent may also require that any such signatures be confirmed by a
manually-signed copy thereof; provided, however, that the failure to request or
deliver any such manually-signed copy shall not affect the effectiveness of any
facsimile signature.

                  This Amendment (other than Section 1 hereof, the effectiveness
of which shall be governed by Section 2 hereof) shall become effective upon the
first date on which: (i) Borrowers, and Requisite Lenders shall have each
executed a counterpart hereof, and (ii) Company, Administrative Agent and
Documentation Agent shall have received written or telephonic notification of
such execution and authorization of delivery of such counterparts.

                [Remainder of this page intentionally left blank]





                                       10
<PAGE>




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


BORROWERS:

                                   COVANTA ENERGY CORPORATION


                                   By:  /s/ Anthony Orlando
                                        ---------------------------------------
                                        Name:  Anthony Orlando
                                        Title: Authorized Officer


                                   EACH OF THE ENTITIES NAMED ON SCHEDULE 1
                                   ANNEXED HERETO, as a Borrower

                                   By:  /s/ Anthony Orlando
                                        ---------------------------------------
                                        Name:  Anthony Orlando
                                        Title: Authorized Officer


                                      S-1
<PAGE>


                                   SCHEDULE 1

                                 Other Borrowers

1.       AMOR 14 Corporation
2.       Burney Mountain Power
3.       Covanta Acquisition, Inc.
4.       Covanta Alexandria/Arlington, Inc.
5.       Covanta Bessemer, Inc.
6.       Covanta Bristol, Inc.
7.       Covanta Cunningham Environmental Support, Inc.
8.       Covanta Energy Americas, Inc.
9.       Covanta Energy Construction, Inc.
10.      Covanta Energy Group, Inc.
11.      Covanta Energy International, Inc.
12.      Covanta Energy Resource Corp.
13.      Covanta Energy Services, Inc.
14.      Covanta Energy West, Inc.
15.      Covanta Engineering Services, Inc.
16.      Covanta Fairfax, Inc.
17.      Covanta Geothermal Operations Holdings, Inc.
18.      Covanta Geothermal Operations, Inc.
19.      Covanta Haverhill Properties, Inc.
20.      Covanta Haverhill, Inc.
21.      Covanta Heber Field Energy, Inc.
22.      Covanta Hennepin Energy Resource Co., Limited Partnership
23.      Covanta Hillsborough, Inc.
24.      Covanta Honolulu Resource Recovery Venture
25.      Covanta Huntsville, Inc.
26.      Covanta Hydro Energy, Inc.
27.      Covanta Hydro Operations West, Inc.
28.      Covanta Hydro Operations, Inc.
29.      Covanta Imperial Power Services, Inc.
30.      Covanta Indianapolis, Inc.
31.      Covanta Kent, Inc.
32.      Covanta Lancaster, Inc.
33.      Covanta Lee, Inc.
34.      Covanta Long Island, Inc.
35.      Covanta Marion Land Corp.
36.      Covanta Marion, Inc.
37.      Covanta Mid-Conn, Inc.
38.      Covanta Montgomery, Inc.
39.      Covanta New Martinsville Hydroelectric Corporation
40.      Covanta New Martinsville Hydro-Operations Corporation
41.      Covanta Oahu Waste Energy Recovery, Inc.



                                       2
<PAGE>

42.      Covanta Omega Lease, Inc.
43.      Covanta Onondaga Operations, Inc.
44.      Covanta Operations of Union, LLC
45.      Covanta OPW Associates, Inc.
46.      Covanta OPWH, Inc.
47.      Covanta Pasco, Inc.
48.      Covanta Plant Services of New Jersey, Inc.
49.      Covanta Power Equity Corporation
50.      Covanta Power Pacific, Inc.
51.      Covanta Power Plant Operations
52.      Covanta Projects of Hawaii, Inc.
53.      Covanta Projects, Inc.
54.      Covanta RRS Holdings, Inc.
55.      Covanta Secure Services, Inc.
56.      Covanta SIGC Energy, Inc.
57.      Covanta SIGC Energy II, Inc.
58.      Covanta SIGC Geothermal Operations, Inc.
59.      Covanta Stanislaus, Inc.
60.      Covanta Systems, LLC
61.      Covanta Tampa Bay, Inc.
62.      Covanta Tampa Construction, Inc.
63.      Covanta Wallingford Associates, Inc.
64.      Covanta Waste to Energy , LLC
65.      Covanta Water Holdings, Inc.
66.      Covanta Water Systems, Inc.
67.      Covanta Water Treatment Services, Inc.
68.      DSS Environmental, Inc.
69.      ERC Energy II, Inc.
70.      ERC Energy, Inc.
71.      Haverhill Power, LLC
72.      Heber Field Energy II, Inc.
73.      Heber Loan Partners
74.      LMI, Inc.
75.      Mammoth Geothermal Company
76.      Mammoth Power Company
77.      Michigan Waste Energy, Inc.
78.      Mt. Lassen Power
79.      Pacific Geothermal Company
80.      Pacific Oroville Power, Inc.
81.      Pacific Wood Fuels Company
82.      Pacific Wood Services Company
83.      Penrose Landfill Gas Conversion, LLC
84.      Three Mountain Operations, Inc.
85.      Three Mountain Power, LLC
86.      Toyon Landfill Gas Conversion, LLC


                                       3
<PAGE>


AGENTS AND LENDERS:


                                    BANK OF AMERICA, N.A.,
                                    as Administrative Agent


                                    By:  /s/ Robert. J. Rittelmeyer
                                         --------------------------------------
                                         Name:  Robert. J. Rittelmeyer
                                         Title: Vice President



                                       4

<PAGE>




                                    DEUTSCHE BANK AG, NEW YORK BRANCH,
                                    as Documentation Agent and as a Lender


                                    By:  /s/ Keith C. Braun
                                         --------------------------------------
                                         Keith C. Braun
                                         Director


                                    By:  /s/ David Bell
                                         --------------------------------------
                                         David Bell
                                         Managing Director



                                       5
<PAGE>


                                    BANK OF AMERICA SECURITIES LLC,
                                    as agent for Bank of America, N.A.
                                    as a Lender


                                    By:  /s/ Toby Gilbert
                                         --------------------------------------
                                         Name:  Toby Gilbert
                                         Title: Associate



                                       6
<PAGE>


                                    BANK OF NEW YORK,
                                    as a Lender


                                    By:  /s/ Peter W. Helt
                                         --------------------------------------
                                         Name:  Peter W. Helt
                                         Title: Vice President



                                       7
<PAGE>


                                    BAYERISCHE HYPO-UND VEREINSBANK AG,
                                    as a Lender


                                    By:  /s/ John W. Sweeney
                                         --------------------------------------
                                         Name:  John W. Sweeney
                                         Title: Director


                                    By:  /s/ Michael D. Novellino
                                         --------------------------------------
                                         Name:  Michael D. Novellino
                                         Title: Director





                                       8

<PAGE>


                                    BEAR STEARNS & CO INC.,
                                    as a Lender


                                    By:   /s/ John E. McDermott
                                         --------------------------------------
                                         Name:  John E. McDermott
                                         Title: Senior Managing Director



                                       9
<PAGE>


                                    IIB BANK LIMITED,
                                    as a Lender


                                    By:  /s/ John O'Connor
                                         --------------------------------------
                                         Name:  John O'Connor
                                         Title: Vice President


                                    By:  /s/ Brian Dunne
                                         --------------------------------------
                                         Name:  Brian Dunne
                                         Title: Authorized Signatory






                                       10
<PAGE>


                                    KBC BANK NV, NEW YORK BRANCH
                                    as a Lender


                                    By:  /s/ Jose Polloarpio, Jr.
                                         --------------------------------------
                                         Name:  Jose Polloarpio, Jr.
                                         Title: Assistant Vice President


                                    By:  /s/ Robert Snauffer
                                         --------------------------------------
                                         Name:   Robert Snauffer
                                         Title:  First Vice President






                                       11
<PAGE>


                                    LANDESBANK HESSEN-THUERINGEN GIROZENTRALE,
                                    as a Lender


                                    By:   /s/ David A. Leech
                                         --------------------------------------
                                         Name:   David A. Leech
                                         Title:  Vice President
                                                 Corporate Finance Division
                                                 Structured Finance Dept.


                                    By:    /s/ Shan Chakraborty
                                         --------------------------------------
                                         Name:   Shan Chakraborty
                                         Title:  Assistant Vice President
                                                 Corporate Finance Division
                                                 Structured Finance Dept.


                                       12

<PAGE>


                                    MERRILL LYNCH, PIERCE, FENNER & SMITH,
                                    INCORPORATED,
                                    as a Lender


                                    By:  /s/ Ronald Torok
                                         --------------------------------------
                                         Name:  Ronald Torok
                                         Title: Director


                                       13

<PAGE>


                                    UBS LOAN FINANCE, LLC,
                                    as a Lender


                                    By:  /s/ Wilfred V. Saint
                                         --------------------------------------
                                         Name:   Wilfred V. Saint
                                         Title:  Director
                                                 Banking Products
                                                 Services, US


                                    By:    /s/ Winslowe Ogboure
                                         --------------------------------------
                                         Name:   Winslowe Ogboure
                                         Title:  Assistant Director
                                                 Banking Products
                                                 Services, US





                                       14

<PAGE>


                                    US BANK NATIONAL ASSOCIATION,
                                    as a Lender


                                    By:
                                         --------------------------------------
                                         Name:
                                         Title:





                                       15

<PAGE>





                                     ANNEX A


                                 See attachment.






                                   Annex A-1

<PAGE>



                                SCHEDULE 7.4(iv)

                    CERTAIN EXISTING PERFORMANCE GUARANTIES*

1.       Covanta Guaranty, dated October 1, 1985, between Covanta Energy
         Corporation and the City of Alexandria; Alexandria Sanitation
         Authority; Arlington County and Arlington Solid Waste Authority, as
         amended;

2.       Covanta Guaranty, dated December 20, 1985, between Covanta Energy
         Corporation, Town of Babylon and the Town of Babylon Industrial
         Development Agency;(1)

3.       Covanta Guaranty, dated August 1, 1985, between Covanta Energy
         Corporation and City of Bristol; Town of Berlin; Town of Burlington;
         City of New Britain; Town of Plainville; Town of Plymouth; Town of
         Southington; Town of Washington;

4.       Covanta Guaranty, dated October 1, 1996, between Covanta Energy
         Corporation and Town of Branford, CT; Town of Hartland, CT; and Town of
         Seymour, CT.

5.       Covanta Guaranty, dated February 1, 1988, between Covanta Energy
         Corporation and County of Fairfax; Fairfax County Solid Waste
         Authority;

6.       Covanta Guaranty, dated December 23, 1986, between Covanta Energy
         Corporation and New England Power Co., as amended;

7.       Covanta Guaranty, dated August 1998, between Covanta Energy Corporation
         and Covanta Haverhill Associates (f/k/a Ogden Haverhill Associates);

8.       Covanta Guaranty, dated July 8, 2003, between Covanta Energy
         Corporation and County of Hennepin;

9.       Covanta Guaranty, dated January 9, 1985, between Covanta Energy
         Corporation and Hillsborough County, Florida;

10.      Covanta Operating Guaranty, dated December 21, 1992, between Covanta
         Energy Corporation and City and County of Honolulu;



----------

         Note: With respect to Waste to Energy Performance Guaranties with
client communities the operating subsidiary has agreed to pay, and Covanta
Energy Corporation, or an Affiliate, has guaranteed payment of, damages intended
to compensate its customer for lost energy revenues, lack of waste processing
capacity, or excess waste residue. Based upon the Company's performance at each
facility and its system generally, it believes that there is no likelihood that
such damages will be payable.

* Emergence entities may have certain outstanding obligations with respect to
Bankrupt Subsidiaries; however, we cannot make representations that agreements
will be assumed prior to the emergence of those entities.

(1) This entity is a Bankrupt Subsidiary. No decision has been made yet to
assume or reject the contracts listed for this Subsidiary. The Bankrupt
Subsidiary reserves its right under Section 365 of the Bankruptcy Code to assume
or reject each of the contracts listed.

<PAGE>

11.      Covanta Liquidated Damages Guaranty, dated July 7, 1993, between
         Covanta Energy Corporation and City and County of Honolulu; Connecticut
         Bank and Trust, Hawaii Solid Waste Disposal, Energy & Resource Recovery
         Facility Trust (assigned to OPI 12/21/92);

12.      Amended and Restated Covanta Guaranty, dated June 29, 1989, between
         Covanta Energy Corporation and Town of Huntington;

13.      Covanta Guaranty, dated June 1, 1988, between Covanta Energy
         Corporation and Solid Waste Disposal Authority of the City of
         Huntsville;

14.      Covanta Guaranty, dated December 1, 1985, between Covanta Energy
         Corporation and City of Indianapolis;

15.      Covanta Guaranty, dated October 1, 1987, between Covanta Energy
         Corporation and County of Kent; Department of Public Works;

16.      Covanta Guaranty, dated September 25, 1987, between Covanta Energy
         Corporation and Lancaster County Solid Waste Management Authority;

17.      Covanta Guaranty, dated January 16, 1990, between Covanta Energy
         Corporation and Lee County, as amended;

18.      Guaranty Agreement, dated December 11, 1986, of Ogden Corporation re:
         Obligations of Ogden Martin Systems of Marion, Inc. and Ogden Marion
         Land Corp. to Columbia Williamette Leasing, Inc.

19.      Covanta Guaranty, dated September 10, 1984, between Covanta Energy
         Corporation and Portland General Electric Co.;

20.      Covanta Guaranty, dated September 10, 1984, between Covanta Energy
         Corporation and Marion County Oregon;

21.      Covanta Guaranty, dated December 21, 1992, and reaffirmed on July 1,
         1996, between Covanta Energy Corporation and Greater Detroit Resource
         Authority;

22.      Covanta Guaranty, dated December 21, 1992, between Covanta Energy
         Corporation and The Detroit Edison Co.;

23.      Covanta Guaranty, dated October 21, 1991, and amended July 1, 1996,
         between Covanta Energy Corporation and Ogden Projects, Inc., Michigan
         Waste to Energy, and Greater Detroit Resource Authority;

24.      Assignment and Assumption Agreement, dated December 21, 1992, between
         Combustion Engineering, Inc., and Covanta Projects, Inc.;

25.      Covanta Guaranty, dated November 16, 1990, between Covanta Energy
         Corporation and Northeast Maryland Waste Disposal Authority;

26.      Amended and Restated Covanta Guaranty, dated November 15, 1992, between
         Covanta Energy Corporation and Onondaga County Resource Recovery
         Agency;

27.      Guarantee Agreement, dated October 10, 2003, between Covanta Energy
         Corporation and Covanta Onondaga Limited Partnership;



                                        2
<PAGE>

28.      Covanta Guaranty, dated April 15, 1989, between Covanta Energy
         Corporation and Pasco County;

29.      Covanta Guaranty, dated May 1, 1990, between Covanta Energy Corporation
         and City of Modesto and County of Stanislaus;

30.      Covanta Guaranty, dated June 1, 1998, between Covanta Energy
         Corporation and Covanta Union, Inc.;

31.      Covanta Guaranty, dated February 1, 1990, between Covanta Energy
         Corporation and Connecticut Resources Recovery Authority (Wallingford);

32.      Guaranty, dated June 1, 1998, between Ogden Projects Inc. and
         Government Utilities Service Corporation;

33.      Guaranty, dated December 15, 1989, between Covanta Power Pacific Inc.
         and Puget Sound Power & Light Company; and

34.      Guaranty, dated December 19, 2000, effective as of December 22, 2000,
         between Covanta Energy Group, Inc. and the Connecticut Resources
         Recovery Authority.



                                       3
<PAGE>



                                SCHEDULE 7.4(vi)


                     CERTAIN EXISTING CONTINGENT OBLIGATIONS

<Table>
<Caption>
Project                Description                        Exposure                Agreement, as amended to date
-------                -----------                        --------                -----------------------------
<S>                  <C>                                  <C>               <C>
Babylon              Interest Rate Swap                          N/A        Interest Rate Swap Agreement, dated August 1,
                                                                            1985, between Covanta Babylon, Inc. and AIG
                                                                            Financial Product Corporation.

Bessemer             OPI's Guarantee of Service                   $0        Guarantee, dated June 1, 1998, by Covanta
                     Agreement ("S.A.") obligations,                        Projects, Inc. for the benefit of The Governmental
                     capped at $3 million                                   Utility Services Corporation of the City of
                                                                            Bessemer.

Bristol              Guarantee of performance                     $0        Electricity Guarantee, dated as of August 1, 1985,
                     obligations under Power Purchase                       by Covanta Energy Corporation to and for the
                     Agreement ("PPA").                                     benefit of The Connecticut Light and Power Company.

CEC                  Indemnity Agreement guarantees       $4,600,000        Schedule of Policies and Payments -- Paid Loss
                     CEC's obligations to reimburse                         Payments Plan and Payment Agreement, dated October
                     amounts paid by AIG for losses                         20, 2002, between National Union Fire Insurance
                     and expenses under the retention                       Company of Pittsburgh, PA, on behalf of itself and
                     for Workers' Compensation,                             all its affiliates including but not limited to
                     General Liability for Workers'                         American Home Assurance Company, The Insurance
                     Compensation, General Liability                        Company of the State of Pennsylvania, National
                     for the policy period.  This is a                      Union Fire Insurance Company of Pittsburgh, PA.,
                     post petition insurance policy.                        Commerce and Industry Insurance Company, Birmingham
                                                                            Fire Insurance Company, Illinois National Insurance
                                                                            Company, American International South Insurance
                                                                            Company, AIU Insurance Company and Covanta Energy
                                                                            Corporation.

CEC                  Program Agreement guarantees         $3,900,000        Program Agreement, dated October 20, 2003, between
                     CEC's obligations to reimburse                         ACE American Insurance Company and Covanta Energy
                     amounts paid by ACE for losses                         Corporation, Inc.
                     and expenses under the retention
                     for Workers' Compensation,
                     General

</TABLE>

                                        4
<PAGE>

<Table>
<Caption>
Project                Description                        Exposure                Agreement, as amended to date
-------                -----------                        --------                -----------------------------
<S>                  <C>                                  <C>               <C>
                     Liability Automobile
                     Liability for the policy period.
                     This is a post petition insurance
                     policy.


Haripur              Performance L/C's securing                   $0        $2,630,232 L/C issued per Application for Standby
                     obligations under Power Purchase                       Letter of Credit, dated November 21, 1999, between
                     Agreement ("PPA")                                      Covanta Energy Corporation and Citibank.

Hartford (Mid-Conn)  Guarantee of performance to operate  $5,000,000        Guaranty, dated December 19, 2000, effective as of
                     the electric generation facility                       December 22, 2000, between Covanta Energy Group,
                     pursuant to the Operations                             Inc. and the Connecticut Resources Recovery
                     Agreement.                                             Authority.

Huntington           Guarantee of Partnership                     $0        Covanta Corporation Guarantee Agreement, dated
                     obligations, including tax                             January 30, 1992, by Covanta Energy Corporation to
                     indemnity and termination put                          Allstate Insurance Co. and Ogden Martin Systems of
                     price.                                                 Huntington Resource Recovery Nine Corporation.

                                                                            First Amended & Restated Ogden Corporation
                                                                            Guarantee Agreement, dated January 30, 1992, for
                                                                            Mission Zeta and Pitney Bowes Credit Corporation

Koma Kulshan         Guarantee of PPA Obligations                 $0        Guarantee:  dated December 15, 1989, by Covanta
                                                                            Power Projects, Inc. (f/k/a Pacific Energy) for
                                                                            the benefit of Puget Sound Power & Light Company

LICA                 Cash deposit supporting LICA L/C       $300,000        Letter Agreement between Covanta Energy
                                                                            Corporation and Bank of America regarding $300,000
                                                                            cash deposit in support of the LICA Letter of
                                                                            Credit issued by Bank of America.

Union                Guarantee of Operating Lease        $18,195,000        Subordinated Rent Guarantee Agreement, dated June 1,
                     Obligations                          (Principal        1998, by Covanta Energy Corporation for the benefit of
                                                       Amount O/S on        the Union County Utilities Authority and Summit
                                                        Subordinated
</TABLE>


                                       5
<PAGE>

<Table>
<Caption>
Project                Description                        Exposure                Agreement, as amended to date
-------                -----------                        --------                -----------------------------
<S>                  <C>                                  <C>               <C>
                                                        Lease Bonds)        Bank, as Trustee.

</Table>



NOTE 1: Where a "$0" appears in the "Exposure" column, this represents the
Company's reasonable expectation related to the applicable Contingent
Obligation.

a. OMS Babylon has no obligation to pay AIG unless Town of Babylon pays Covanta
Babylon (i.e., The cost of the Swap is a pass through to the client.)



                                       6
<PAGE>




                           ACKNOWLEDGMENT AND CONSENT


Reference is made to (i) that certain Credit Agreement (the "CREDIT AGREEMENT")
dated as of March 10, 2004 by and among by and among COVANTA ENERGY CORPORATION,
a Delaware corporation ("COMPANY"), and THE SUBSIDIARIES OF COMPANY LISTED ON
THE SIGNATURE PAGES THEREOF AS BORROWERS (collectively, Company and such
Subsidiaries of Company are "BORROWERS" and each a "BORROWER"), THE LENDERS
PARTY THERETO, BANK OF AMERICA, N.A., as Administrative Agent for the Lenders
("ADMINISTRATIVE AGENT"), and DEUTSCHE BANK SECURITIES, INC., as Documentation
Agent for the Lenders ("DOCUMENTATION AGENT") and (ii) that certain First
Amendment to Credit Agreement (the "AMENDMENT") dated as of December 15, 2004 by
and among Borrowers, the financial institutions parties thereto as Lenders,
Documentation Agent and Administrative Agent. Capitalized terms used herein
without definition shall have the same meanings herein as set forth in the
Credit Agreement (as amended by the Amendment). Danielson Holding Corporation, a
Delaware corporation ("DHC"), hereby acknowledges that it has read the Amendment
and consents to the terms thereof and further hereby confirms and agrees that,
notwithstanding the effectiveness of the Amendment, the obligations of DHC under
each of the Credit Documents to which it is a party shall not be impaired and
each of the Credit Documents to which DHC is a party are, and shall continue to
be, in full force and effect and are hereby confirmed and ratified in all
respects.


On and after the First Amendment Effective Date (as defined in the Amendment),
each reference in the Credit Documents to which DHC is a party to the "Credit
Agreement", "thereunder", "thereof" or words of like import referring to the
Credit Agreement shall mean and be a reference to the Credit Agreement as
amended by the Amendment.


THIS ACKNOWLEDGMENT AND CONSENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES
HEREUNDER SHALL BE GOVERNED BY, AND SHALL BE CONSTRUED AND ENFORCED IN
ACCORDANCE WITH, THE INTERNAL LAWS OF THE STATE OF NEW YORK (INCLUDING WITHOUT
LIMITATION SECTION 5-1401 OF THE GENERAL OBLIGATIONS LAW OF THE STATE OF NEW
YORK), WITHOUT REGARD TO CONFLICTS OF LAWS PRINCIPLES.


                                        DANIELSON HOLDING CORPORATION,
                                        as a Credit Party


                                        By:  /s/ Anthony J. Orlando
                                             -----------------------------------
                                             Name:  Anthony J. Orlando
                                             Title: CEO and President




                                Acknowledgment-1