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| 1.     | Definitions                                                                                                                                                                                                                                                    |
|--------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   | 1.1.       The following terms, as used anywhere in this Agreement, have the      same meaning that they have in the ICA:  “Shared Costs,”“Final Cost      Allocation,”and      “Coordinator/Utility.” |

| 2. | Final      Cost Allocation |
|----|----------------------------|

|   | 2.1.  Except as specified in      paragraph 2.3, with      respect to the Sites listed on Attachment A to this Agreement, the Final      Cost Allocation shall      be and shall result in Nicor being responsible for 51.73 percent, and      ComEd being responsible for 48.27 percent, of any and all past and future      Shared Costs. |
|--------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 2.2.  Except as specified in      paragraph 2.3, with      respect to the Sites listed on Attachment B to this Agreement, the Final Cost Allocation shall      be and shall result in Nicor being responsible for 0 percent, and ComEd      being responsible for 100 percent, of any and all past and future Shared      Costs.  ComEd will become the Coordinator/Utility at      any and all Sites      listed on Attachment B other than the Site described on Attachment B as      “MGP Site at Clinton      and Jackson, Ottawa,Illinois.” |
|--------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

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|   | 2.3.  The parties recognize      that there may be Shared Costs that do not relate      exclusively either to the Sites listed on Attachment A or to the Sites      listed on Attachment B, but rather relate to the Utilities’MGP remediation program in general      (“Program      Costs”).  Program Costs could      include, by way of example and without limitation, costs associated with      site prioritization,      costs associated with jointly owned equipment and costs associated with      producing documentation to provide general instructions to contractors      relating to the site      investigations and remediations.   TheFinal Cost Allocation shall be and      shall result in Nicor      being responsible for 50 percent, and ComEd being responsible for 50      percent, of any and all past and future Program    Costs. |
|--------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 2.4.  On the date of ICC      approval of this Agreement, to the extent that either Utility has paid      more or less than the amounts determined by the percentages in      paragraphs 2.1 through 2.3 of this Agreement, appropriate credits and      debits, if required, will be made promptly to reflect the agreed upon      percentage of each Utility’s Final Cost Allocation, as      specified in paragraphs 2.1 through 2.3.  These credits      and debits will be reflected in invoices for future remediation costs at      Sites listed on AttachmentA. |
|--------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 3. | ICC      Approval |
|----|-------------------|

|   | 3.1.  This      Agreement, including      the prudence and      reasonableness of the      Final Cost Allocations set forth in section 2 and the indemnities set forth in      section 5 below, is      subject to and contingent upon approval by the  ICC. |
|--------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 3.2.  The Utilities agree to      use their best efforts, and to act in good faith, promptly to seek and      obtain ICC approval of this Agreement, including the Final Cost Allocations and indemnities      set forth herein. |
|--------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

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|   | 3.3.  In the event that the      ICC does not approve this Agreement, including the Final Cost Allocations and      indemnities set forth herein, this Agreement and the MOU shall      be void,but the ICA shall remain in full      force and      effect. |
|--------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 3.4.  In the event that the      ICC approves this Agreement, including the Final Cost Allocations and      indemnities set forth herein, (a) this Agreement shall supersede      the MOU, (b) this Agreement shall control in the event of any conflict      between this      Agreement and the MOUor any conflict between this      Agreement and the ICA, and (c) the date of such      approval shall be the Effective Date of this    Agreement. |
|--------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 3.5.  If, before the ICC      approvals      contemplated by this      Agreement become final and non-appealable, the Illinois General Assembly approves      a change in Illinois law such that either party reasonably anticipates      that it may be prevented by such change from obtaining, in whole or in      part, recovery from customers of Shared Costs, then either party so      potentially      affected by such      legislative action shall have the right to terminate the MOU and this      Agreement, by giving notice of such termination to the other party within      thirty (30) days of such change.  In the event of such      termination, neither Utility shall have any continuing obligation under      either the MOU or thisAgreement. |
|--------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 4. | Pending      Arbitration |
|----|--------------------------|

|   | 4.1.  Upon execution of this      Agreement, the Utilities will jointly request that the stay of Arbitration      be continued pending the ICC’s review and approval of this      Agreement, including the Final Cost Allocations and the      indemnities set forthherein. |
|--------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

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|   | 4.2.  If and when a final      Order of the ICC approving this Agreement, including the Final Cost Allocations and      indemnities set forth herein,becomes non-appealable, the      Utilities will request that the Arbitration be dismissed      with prejudice. |
|--------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 4.3.  In the event the ICC      does not approve      this Agreement,      including      the Final Cost      Allocations and indemnities set forth herein, or in the event of termination of      this Agreement as provided in paragraph 3.5, either Utility may reinstate      the Arbitration, in which case neither Utility will be deemed to have      waived any claim, right, or defense as a result of the MOU or this      Agreement, and neither the MOU nor this Agreement nor any communication or      document related to either will be      admissible in any way in any reinstated  Arbitration. |
|--------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 5. | Release      and Indemnity |
|----|----------------------------|

|   | 5.1.  Effective upon a final      Order of the ICC approving this Agreement, including the Final Cost Allocations and      indemnities set forth herein, becoming non-appealable, each Utility releases the      other from all claims      for liability with respect to Shared Costs (other than as may arise out of      the agreed Final Cost Allocations described in section 2 and except as may be necessary to      effectuate the indemnities provided in paragraphs 5.2 and      5.3). |
|--------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | 5.2.  Effective upon a final      Order of the ICC approving this Agreement, including the Final Cost Allocations and      indemnities set forth herein, becoming non-appealable,      each Utility hereby indemnifies and      agrees to defend and hold harmless the other against liability, including but not      limited to any liability arising out of or relating to remediation, to any      third party arising out of or relating to any of the Sites listed on      Attachment A, for      costs that are      recoverable through the indemnifying party’s rider |
|--------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

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|   | described hereafter (as such rider(s) may be amended from time to      time):  ComEd’s Rider ECR (Ill. C. C. No. 4,      sheet nos. 438 through 440.2, filed Aug. 11, 2006) or Nicor’s Rider 12 (Ill. C. C. No. 16,      sheet nos. 68-70, filed Sept. 30, 2005).  The indemnification      provided in this paragraph 5.2 is limited to the amount necessary to allow the Utilities      to share in such third-party liability in the same proportion as the Final      Cost Allocations set out in paragraph 2.1.  The indemnification provided in this paragraph is      in addition to any other indemnification rights, common law or otherwise,      that the parties may have.                                                                                                                                               |
|--------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   | 5.3.  Effective upon a final      Order of the ICC approving this Agreement, including the Final Cost Allocations and      indemnities set forth      herein, becoming non-appealable,      ComEd hereby      indemnifies and agrees to defend and hold harmless Nicor against liability, including but not limited to any      liability arising out of or relating to remediation, to any third party      arising out of or relating to any of the Sites listed on Attachment B, for costs that are recoverable      through ComEd’s Rider ECR (Ill. C. C. No. 4,      sheet nos. 438 through 440.2, filed August 11, 2006), as such rider may be      amended from time to time. The indemnification      provided in this      paragraph is in addition to any other indemnification rights, common law      or otherwise, that the parties mayhave. |

| 6. | Entire      Agreement.  This Agreement and the      Attachments to this Agreement (which are part of this Agreement)      constitute the entire understanding of the Utilities with      respect to this Agreement.  No modification may be made to this      Agreement except one signed by both Utilities that expressly states that      it modifies this Agreement. |
|----|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

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| 7. | Successors      and Assigns.  This Agreement shall      be binding upon the      successors and assigns of the Utilities; provided that neither Utility can assign its rights      under this Agreement without the other Utility’s  consent. |
|----|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 8. | Applicable      Law.  This      Agreement shall be interpreted under the laws of the State of      Illinois. |
|----|------------------------------------------------------------------------------------------------------------------------|

| 9. | Dispute      Resolution. The parties agree to attempt to      resolve any dispute arising out of or relating to this      Agreement or its breach through good faith      negotiation.  If good faith negotiation fails to resolve the dispute,      then the parties agree to submit      the dispute to non-binding mediation and      acknowledge that the role of the mediator is not to render a decision, but      to assist the parties in reaching a mutually acceptable      resolution.  No party shall be bound by anything said or done in      the course of mediation other than through an agreement in writing      executed by both      Utilities.  If mediation fails to      settle the dispute, then the parties agree that the dispute      shall be settled by      arbitration under and in accordance with      the ICA.  |
|----|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 10. | Nonwaiver.  The      Utilities do not      admit liability at any of the Sites listed in Attachments A or      B.  Except as otherwise provided in this Agreement, the      Utilities do not waive any rights or defenses, including rights to seek      recovery of any costs that are recoverable through their respective      environmental-cost-recovery riders, as described in paragraph      5.2. |
|-----|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 11. | Method      of Execution.  This Agreement may be      executed in multiple counterparts, each of which shall be deemed an      original, but all of which together shall constitute one and      the same      agreement. |
|-----|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

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|   | 1. | Aurora Gas Light Company, River      St. at North Avenue Bridge,Aurora |
|--------|----|------------------------------------------------------------------------|

|   | 2. | Belvidere Gas, Light & Fuel,      Locust Street, Belvidere |
|--------|----|----------------------------------------------------------------|

|   | 3. | Chicago Heights Gas Company, 17th & State      Street, Chicago Heights |
|--------|----|----------------------------------------------------------------------------|

|   | 4. | Cicero gas Company, Lombard &      Garfield, Oak Park |
|--------|----|-----------------------------------------------------------|

|   | 5. | Coal Products manufacturing      Company, North Broadway,Lockport |
|--------|----|-------------------------------------------------------------------|

|   | 6. | Freeport Gas, Light & Coke      Company, Liberty & Jackson St.,  Freeport |
|--------|----|-----------------------------------------------------------------------------------|

|   | 7. | Geneseo Electric Light &      Gas Company, Oakwood      & First St., Geneseo |
|--------|----|--------------------------------------------------------------------------------------|

|   | 8. | Illinois Northern Utility Company,      Market & 14th, DeKalb |
|--------|----|-------------------------------------------------------------------|

|   | 9.        | Illinois Northern Utilities      Company, 227 Miller, Sterling                    |
|--------|-----------|-----------------------------------------------------------------------------------|
|   | 10.  | Joliet Gaslight Company, Station      B, North Broadway & Ingalls St., Joliet |
|   | 11.  | Kankakee Gas Company,      Birch& Harrison      St., Kankakee                 |
|   | 12.  | LaGrange Gas Company, 47th &      Bluff St., LaGrange                         |
|   | 13.  | Lemont Gas, Light Company, Main      & Lockport Rd., Lemont                   |
|   | 14.  | Lincoln Water, Light & Gas      Company, Sangamon & Dacatur St., Lincoln  |
|   | 15.  | Lockport Gas Company, 17th & I      & M Canal, Lockport                   |
|   | 16.  | Mendota Gas Company, Fifth St. & Ninth      Ave., Mendota                     |
|   | 17.  | Morris gas Company, Nettle &      Jackson St., Morris                         |
|   | 18.  | Morrison Gas & Electric,      Market & S. Orange,Morrison                 |

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|   | 19.       | Northwestern      Gas, Light & Coke Company, 912 Clark St., Evanston                                        |
|--------|-----------|-----------------------------------------------------------------------------------------------------------------|
|   | 20.  | Northwestern Gas, Light & Coke      Company,      Maple & Vermont,      Blue Island                     |
|   | 21.  | Northwestern Gas, Light & Coke      Co./Niles Center Station, Oakton St. & McCormick Blvd.,      Skokie |
|   | 22.  | Ottawa Gas, Light & Coke      Company, Illinois & Walker St., Ottawa                                    |
|   | 23.  | Pontiac Light & Water Company,      Vermillion & Water St., Pontiac                                     |
|   | 24.  | Streator Gas, Light & Coke Co., Water      St. & Vermillion Rr.,Streator                                |

  

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|   | 1. | MGP Site on Coal Gas Road,      DuQuoin, Illinois |
|--------|----|---------------------------------------------------|

|   | 2. | MGP Site on Bluff Street, Joliet,      Illinois |
|--------|----|-------------------------------------------------|

|   | 3. | MGP Site on Center Street,      Geneseo, Illinois |
|--------|----|---------------------------------------------------|

|   | 4. | MGP Site at Clinton and Jackson,      Ottawa, Illinois |
|--------|----|--------------------------------------------------------|

|   | 5. | Dixon I (2nd      St.) |
|--------|----|------------------------|

|   | 6. | Dixon II (River &      Perry) |
|--------|----|-----------------------------------|

|   | 7. | DuQuoin      (Chestnut) |
|--------|----|-------------------------|

|   | 8. | Elgin      TDC-570-0044 |
|--------|----|-------------------------|

|   | 9.  | Kenilworth                       |
|--------|-----|----------------------------------|
|   | 10. | Mendota      (Main St.)          |
|   | 11. | Murphysboro      I (Walnut)      |
|   | 12. | Murphysboro      II (Big Muddy)  |
|   | 13. | Rockford      (Avon & Cedar) |
|   | 14. | Rockford      II (Mulberry)      |

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