EXHIBIT 2.3

                                                                   
                                 ATTACHMENT XXII

                                   ----------


                             ENVIRONMENTAL AGREEMENT


                                 By and Between


                         UNION OIL COMPANY OF CALIFORNIA


                                       and


                                TOSCO CORPORATION



                          ----------------------------

                           Dated as of [Closing Date]
                          ----------------------------










                             ENVIRONMENTAL AGREEMENT



         THIS   ENVIRONMENTAL   AGREEMENT   is  dated  as  of   [Closing   Date]
("Agreement"), between UNION OIL COMPANY OF CALIFORNIA, a California corporation
and TOSCO CORPORATION, a Nevada Corporation.

                                    RECITALS

                 WHEREAS,  Seller and  Purchaser  have  entered  into a Sale and
Purchase  Agreement For 76 Products  Company dated  December 14, 1996 ("Sale and
Purchase  Agreement"),  pursuant  to which  Purchaser  agreed to buy and  Seller
agreed to sell the business and assets that  constitute the 76 Products  Company
business segment of Seller; and

                 WHEREAS,  the Sale and Purchase  Agreement provides that Seller
and Purchaser  will enter into an  Environmental  Agreement at Closing to be the
exclusive statement of the representations,  warranties,  covenants,  agreements
and  indemnities  with  respect  to  Environmental  Laws as they apply to the 76
Products Company business segment.

                 NOW, THEREFORE, the parties agree as follows:

     1.  Definitions.  For all purposes of this  Agreement,  the following terms
shall have the following meanings, and such meanings shall be equally applied to
both the singular and plural forms of the terms defined.


     (a) "Allocated  Overhead Costs" shall have the meaning specified in Section
1(n).

     (b)  "Baseline"  shall mean all  Releases  in or to the  atmosphere,  soil,
surface  water,  subsurface  strata or groundwater at or from the 76 Assets that
occurred prior to the Closing and shall include  Releases,  whenever  occurring,
resulting from Hazardous  Materials sent prior to Closing from the 76 Assets, as
they are  comprised on the Closing  Date,  to a disposal  site  designated  as a
"Superfund" site under the Comprehensive  Environmental  Response,  Compensation
and Liability Act.

     (c)  "Baseline  Amortizing  Amount"  shall have the  meaning  specified  in
Section 4(a).

     (d) "Baseline  Corrective Action Costs" shall have the meaning specified in
Section 4(a).

     (e)  "Baseline  Corrective  Action Costs  Quarterly  Report" shall have the
meaning specified in Section 5(b)(ii).

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     (f)  "Baseline  Development  Period"  shall have the meaning  specified  in
Section 4(b).

     (g)  "Category  I Project"  shall  have the  meaning  specified  in Section
5(c)(i).

     (h)  "Category  II  Projects"  shall have the meaning  specified in Section
5(c)(i).

     (i) "Change Event" shall have the meaning specified in Section 4(a).

     (j) "Claim Notice" shall have the meaning specified in Section 8(c).

     (k) "Closing" shall mean the date and time that the 76 Assets are purchased
by Purchaser under the Sale and Purchase Agreement.

                 (l) "Compliance  Action" shall mean any expenditure or activity
necessary to operate the 76 Assets in compliance with  applicable  Environmental
Laws.

     (m) "Compliance  Action Costs" shall have the meaning  specified in Section
4(c).

     (n)  "Corrective  Action"  shall mean any  expenditure  or  activity  taken
pursuant to Environmental Laws to investigate,  monitor and, if required, abate,
clean up,  remove,  treat,  cover or in any other way  remediate a Release at or
from the 76  Assets,  including  reasonably  incurred  removal,  remediation  or
cleanup costs, site investigation and assessment costs, government oversight and
response  costs  and,  if  applicable,  allocated  costs of  in-house  personnel
necessary to directly  manage or support such  activities  ("Allocated  Overhead
Costs"),  but excluding any allocation of general corporate overhead;  provided,
however,  such  allocated  costs shall not exceed ten percent  (10%) of Baseline
Corrective  Action  Costs.  Corrective  Action  shall also mean any payment of a
third  party's  (including,  but not  limited  to, any  federal,  state or local
government  agency)  claim  for  property  damages,  losses,  expenses,   costs,
deficiencies,   penalties,  liens,  interests,   fines,  assessments,   charges,
obligations or liabilities of any kind, including reasonable attorneys' fees and
court  costs,  arising out of or relating to a Release at or from the 76 Assets;
provided,  however,  Corrective  Action  shall not  include  Compliance  Action,
Retained Environmental Liability,  payment of a third party's claim for personal
injury  (including,  but not  limited  to,  any claim for a  person's  physical,
mental,  psychological,  chemical or  biological  response to the  exposure to a
Hazardous Substance) or punitive damages.

     (o)  "Corrective  Action Plan" shall have the meaning  specified in Section
5(b)(i).

     (p)  "Environmental  Laws"  shall mean any legal  requirement  relating  to
pollution,  protection or cleanup of the environment (including, but not limited
to, ambient air, surface water, groundwater, land surface or subsurface strata),
including,   without  limitation,  the  Comprehensive   Environmental  Response,
Compensation and

                                       2

         
          
Liability Act of 1980, as amended,  the Resources  Conservation and Recovery Act
of 1976, as amended, and any other federal,  state and local legal requirements,
as such  legal  requirements  exist on the  Closing  Date  (except as such legal
requirements   may  be  amended  after  the  Closing  Date  to  modify  existing
remediation standards), relating to: (i) a Release or the containment,  removal,
remediation,  response,  cleanup or abatement of a Hazardous Substance; (ii) the
manufacture,   generation,  formulation,   processing,  labeling,  distribution,
introduction into commerce, use, treatment, handling, storage, or transportation
of a Hazardous Substance;  (iii) exposure of persons,  including employees, to a
Hazardous  Substance;  (iv) occupational  safety or health matters;  and (v) the
physical  structure  or  condition  of a  building,  facility,  fixture or other
structure, including, without limitation, those relating to the management, use,
storage,   disposal,   cleanup  or  removal  of  asbestos,   asbestos-containing
materials, polychlorinated biphenyls or any other Hazardous Substance.

     (q)  "Hazardous  Substance"  shall  mean  any  toxic  substance  or  waste,
pollutant, hazardous substance or waste, contaminant,  special waste, industrial
substance or waste,  petroleum or  petroleum-derived  substance or waste, or any
toxic or  hazardous  constituent  of any such  substance  or  waste,  including,
without  limitation,  any substance  regulated under or defined by Environmental
Laws.

     (r)   "Improvements"   shall  mean  the  permanent   structures  and  other
improvements on the Real Property acquired by Purchaser pursuant to the Sale and
Purchase Agreement.

     (s) "Indemnified Party" and "Indemnifying  Party" shall have the respective
meanings specified in Section 8(c).

     (t) "Independent  Consultant"  shall have the meaning  specified in Section
10(b).

     (u)  "Permit"  shall  mean  any  approval,   registration,   authorization,
certificate, certificate of occupancy, consent, license, order, permit, variance
or  other  similar   authorization   of  any  government   agency   required  by
Environmental  Laws in  effect  on or  prior  to the  Closing  for  the  current
ownership, use or operation of the 76 Assets.

     (v)  "Purchaser"  shall  mean  Tosco  Corporation  and  its  successors  in
interest.

     (w) "Real  Property"  shall mean the real  property  acquired by  Purchaser
pursuant to the Sale and Purchase Agreement.

     (x) "Release" shall mean any spilling, leaking, pumping, pouring, emitting,
emptying,  discharging,  escaping, leaching, dumping or disposing of a Hazardous
Substance  into the  environment  of any  kind  whatsoever,  including,  but not
limited to, the abandonment or discarding of barrels, containers, tanks or other
receptacles containing or previously containing a Hazardous Substance. Migration
of any pre-Closing Release shall not be considered a new Release for purposes of
this Environmental Agreement.

                                       3



     (y)  "Remediation  Equipment"  shall have the meaning  specified in Section
7(d).

     (z)  "Reportable  Quantity of a Hazardous  Substance"  shall mean a Release
which  is  required,  pursuant  to  Environmental  Laws,  to  be  reported  to a
government agency.

     (aa) "Retail Site" shall mean Real Property and  Improvements  used for the
retail sale of motor fuel to the general public.

     (bb) "Retained Environmental Liability" shall mean any liability imposed by
Environmental  Laws arising out of Seller's  pre-Closing  activities  other than
activities  associated with the 76 Assets,  and shall also include any liability
for  any  designated   "Superfund"  site  as  of  the  Closing  Date  under  the
Comprehensive  Environmental Response,  Compensation and Liability Act for which
Seller has been named a "Potentially  Responsible Party" as of the Closing Date.
Retained  Environmental   Liability  shall  not  include  Compliance  Action  or
Corrective Action.

     (ac) "Sale and Purchase  Agreement" shall have the meaning specified in the
first recital of this Agreement.

     (ad) "Seller" shall mean Union Oil Company of California and its successors
in interest.

     (ae) "Special Damages" shall have the meaning specified in Section 7(d).

     (af) "UST Funds" shall have the meaning specified in Section 9(a).

     (ag) "76  Assets"  shall mean the  business  and assets of the 76  Products
Company  business  segment of Seller acquired by Purchaser  pursuant to the Sale
and Purchase Agreement.

     (ah) "$200 Million Cap" shall have the meaning specified in Section 4(a).


     2. SELLER'S ENVIRONMENTAL REPRESENTATIONS.  To Seller's knowledge, Schedule
2A sets  forth an  accurate  and  complete  list of all  Permits  Seller has for
operation of the 76 Assets pursuant to applicable Environmental Laws. Except for
the items set forth in  Schedule 2B to this  Agreement,  to the best of Seller's
knowledge as of the Closing:

                 (a) All Permits  necessary  for the operation of the 76 Assets,
as they are currently  being  operated by Seller,  have been obtained and are in
effect and, where  required,  applications  for renewal thereof have been timely
filed,  except where the failure to obtain such Permits,  individually or in the
aggregate, would not have a significant adverse effect upon the operation of the
76 Assets as they have been operated on a historical basis.

                                       4



                 (b)  The  76  Assets   are  in   compliance   with   applicable
Environmental  Laws  and  Permits,  except  where  the  failure  to be  in  such
compliance would not have a significant  adverse effect on the operations of the
76 Assets as they have been operated on a historical basis.

     3. PURCHASER'S ENVIRONMENTAL  REPRESENTATIONS AFTER DUE DILIGENCE. Based on
Purchaser's  inquiry  and  due  diligence  prior  to the  Closing,  none  of the
representations made above by Seller is inaccurate.

     4. ENVIRONMENTAL PROVISIONS.

                 (a) ALLOCATION OF BASELINE  CORRECTIVE ACTION COSTS.  Except as
otherwise  provided in this Agreement,  Seller shall be responsible for Retained
Environmental  Liability  and the cost of  Corrective  Action  arising out of or
related to the Baseline  ("Baseline  Corrective  Action  Costs"),  and Purchaser
shall be responsible for all other Corrective Action;  provided,  however,  that
Seller's   obligation  for  Baseline   Corrective   Action  Costs  shall  expire
twenty-five  (25)  years  after the  Closing,  except as to  unpaid  amounts  of
Baseline  Corrective Action Costs invoiced to Seller for work performed prior to
such  expiration  and except  Baseline  Corrective  Action  Costs for a discrete
project begun prior to such  expiration and to be completed  within a reasonable
and definite time period (but  excluding  costs  associated  with  monitoring of
environmental  conditions  and other ongoing  non-remediation  costs).  Baseline
Corrective  Action  Costs  shall  include  costs  incurred  to  prevent or abate
migration  of a  pre-Closing  Release at or from a 76 Assets to  adjoining  real
property owned, leased or used by a third party.  Notwithstanding the foregoing,
Purchaser shall pay, during each calendar year, the first $7 million of Baseline
Corrective  Action  Costs  and forty  percent  (40%) of the  amount of  Baseline
Corrective Action Costs (and Seller shall pay the remaining sixty percent (60%))
in excess of the $7 million,  up to a lifetime  aggregate of $200 million ("$200
Million Cap"). Upon and after the occurrence of a Change Event,  Seller shall be
charged annually with its allocated share of the Baseline  Amortizing  Amount in
accordance with the allocation of responsibility for Baseline  Corrective Action
Costs  provided in this Section 4(a).  Purchaser  shall be  responsible  for all
Corrective Action costs in excess of the Baseline  Amortizing  Amount,  and such
costs shall not be included in the  calculation  of the $200 Million  Cap.  Only
Purchaser's  allocated share of the Baseline Amortizing Amount shall be included
in the calculation of the $200 Million Cap.  "Baseline  Amortizing Amount" means
the annual Baseline  Corrective Action Costs with respect to a facility at which
a Change Event has occurred, estimated in good faith using the Corrective Action
Plan as a  guideline  and  assuming  that such  Change  Event had not  occurred.
"Change  Event"  means:  (i) the closure of a 76 Asset site (other than a Retail
Site); and/or (ii) the change in use of a 76 Asset (other than a Retail Site) to
a use outside the  petroleum/chemical  industry.  For purposes of this  Section,
closure means the  termination of  substantially  all operations at a site which
results in an acceleration of or additional Baseline Corrective Action from what
is otherwise set forth in the Corrective  Action Plan prior to the contemplation
of closure of such site,  or if no such  Corrective  Action Plan exists prior to
such contemplation, Seller's existing plans for such site.

                                       5



                 (b) BASELINE DETERMINATION. The Baseline shall be determined by
reference to existing  information from studies performed by or for Seller, such
as described in Seller's existing  Environmental  Remediation  Services Business
Plans for Real Property and  Improvements.  Within six (6) months of the Closing
("Baseline  Development  Period"),  the  Baseline  can be  augmented  by further
investigation that Purchaser determines in good faith is reasonably necessary to
establish the Baseline. Such further investigation shall be performed during the
Baseline  Development  Period (or if Seller in its sole  discretion  agrees to a
longer  period than six (6) months,  during the period as Seller  agrees).  Such
further  investigation  shall be performed at Purchaser's sole expense and shall
not be included in  calculation  of the $200 Million Cap.  Purchaser may further
augment the Baseline after the six (6)-month  period with in situ testing of the
76 Assets that Purchaser,  during the Baseline Development Period, identifies is
reasonably  necessary  to  establish  that a Release  should be  included in the
Baseline, but only to the extent such testing is required by a lawful order of a
government  agency (with  jurisdiction)  to conduct such testing on such site or
Seller agrees such testing is required under  Environmental Laws (such agreement
not to be unreasonably withheld).

                 (c) COMPLIANCE  ACTION COSTS.  Except as otherwise  provided in
this Section 4(c), Seller shall be responsible for the cost of Compliance Action
("Compliance  Action  Costs")  which arise out of or result from  operations  or
conditions  before the Closing.  Purchaser  shall be responsible  for Compliance
Action Costs which arise out of or result from  operations or  conditions  after
the Closing.  Notwithstanding the foregoing,  Purchaser shall be responsible for
Compliance  Action  Costs  associated  with the  construction  and  operation of
facilities  necessary to achieve selenium  effluent  limitations at Seller's San
Francisco  Refinery  and  the  construction  and  operation  of  vapor  recovery
equipment at Seller's Los Angeles  Refinery  Marine Terminal to: (i) comply with
Environmental Laws; or (ii) as may be required in connection with the renewal of
Seller's existing lease for the Terminal.

     5. CONDUCT OF BASELINE CORRECTIVE ACTION.

     (a) If Baseline Corrective Action is required,  Purchaser shall conduct and
pay for such action,  and Seller shall  reimburse  Purchaser in accordance  with
Section  4(a).  During the time Seller is obligated to pay all or any portion of
Baseline Corrective Action Costs, Purchaser shall, within twenty-four (24) hours
after  reporting to the  appropriate  government  agency,  notify  Seller of any
Reportable  Quantity of a Hazardous  Substance.  If a  Reportable  Quantity of a
Hazardous Substance is discovered in the soil, surface water,  subsurface strata
or  groundwater  at a 76 Asset  after  the  Closing  in an  amount  not  readily
distinguishable  from  the  Baseline,  Purchaser  shall be  responsible  for the
incremental  Corrective Action costs associated therewith,  and such costs shall
not be included in the  calculation  of the $200  million cap.  Purchaser  shall
provide to Seller  information  about such an event  sufficient  to estimate the
incremental  Corrective Action costs attributable thereto.  Purchaser and Seller
shall work  together in good faith to agree on such  incremental  costs.  In the
event the parties are unable to reach agreement on such  incremental  costs, the
dispute may be submitted for dispute resolution in accordance with Section 10.


                                       6


     (b) Purchaser shall provide to Seller the following reports and information
in  conjunction  with  Baseline  Corrective  Action  conducted  or planned to be
conducted by Purchaser:

     (i) By September 30 of each calendar year during which  Purchaser  conducts
Baseline  Corrective Action,  Purchaser shall provide Seller with an expenditure
plan detailing its planned Baseline  Corrective Action  expenditures for each of
the next three (3) calendar years  ("Corrective  Action  Plan").  The Corrective
Action  Plan  shall  include   separate  detail   supporting  any  project  with
anticipated  expenditures during the three (3)-year period in excess of $250,000
("Category  I  Project")  and  a  summary  total  of  all  other  projects  with
anticipated  expenditures during the three (3)-year period of less than $250,000
("Category II Projects").

     (ii)  Within  thirty  (30)  days  after the end of each  calendar  quarter,
Purchaser  shall provide Seller with a status report of all Baseline  Corrective
Action Costs Purchaser has incurred  year-to-date  ("Baseline  Corrective Action
Costs Quarterly Report").  The Baseline Corrective Action Costs Quarterly Report
shall  provide a summary of the total  expenditures  incurred  for the  previous
quarter, year-to-date and life-to-date for each Category I Project identified in
the Corrective Action Plan and a summary of the total expenditures  incurred for
the  previous  quarter,  year-to-date  and  life-to-date  for  the  Category  II
Projects.  The expenditures  reported shall segregate Baseline Corrective Action
Costs with a breakdown  within each category  between direct costs and Allocated
Overhead Costs,  and a summary of the amount of all Baseline  Corrective  Action
Costs Purchaser contends should be included in calculating the $200 Million Cap.
The  Baseline  Corrective  Action Costs  Quarterly  Report for each of the first
three quarters of the year shall include an update to the estimated expenditures
for each  Category I Project and for all Category II Projects for the balance of
the current year. The Baseline  Corrective Action Costs Quarterly Report for the
fourth  quarter  shall include an update for the  following  year (i.e.  the 4th
quarter Baseline  Corrective Action Costs Quarterly Report of 1997 will estimate
expenditures  for each  Category I Project and the  Category II Projects for the
calendar year 1998). The Baseline Corrective Action Costs Quarterly Report shall
include an invoice to Seller for Seller's  share of Baseline  Corrective  Action
Costs.  Purchaser  shall  provide  Seller  with  any  documentation   reasonably
requested by Seller that evidences the invoiced amounts.

     (c) Seller shall  reimburse  Purchaser  for Seller's  share of the invoiced
Baseline  Corrective Action Costs within thirty (30) days of Seller's receipt of
such  invoice or,  within  such time,  notify  Purchaser  in writing of disputed
invoiced  amounts and withhold  payment of those amounts.  Only disputed amounts
may be withheld.

     (d) Seller shall have the right, upon reasonable notice, to
audit the Baseline  Corrective Action Costs Quarterly  Reports.  Any adjustments
identified by Seller  through an audit will be presented to Purchaser in writing
for  consideration  to revise the Baseline  Corrective  Action  Costs  Quarterly
Reports and  associated  invoices.  Purchaser and Seller shall  together  review
Seller's  proposed  adjustments  and  negotiate  in good faith to resolve  those
adjustments.  If an  agreement  cannot be reached  within sixty (60) days of the

                                       7


presentment  of the proposed  adjustments,  the  unresolved  adjustments  may be
submitted for dispute resolution in accordance with Section 10.

     (e) Upon Seller's reasonable request, Purchaser shall provide Seller with a
copy of any information relating to Baseline Corrective Action,  including,  but
not limited to, soil assessment data,  laboratory reports,  field study results,
groundwater   monitoring  data,  and  operating  and  maintenance  histories  of
groundwater  recovery  equipment  operated  by  Purchaser  relating  to Baseline
Corrective Action.

     (f)  Seller  shall  have  the  right,  but not the  obligation,  to  notify
Purchaser  in  writing  within  thirty  (30)  days of  Seller's  receipt  of the
Corrective Action Plan of Seller's intent to participate  directly in government
agency contacts and the development of a site assessment or remediation  plan or
project for any Category I Project.  Except in each case to the extent Purchaser
is required to take action pursuant to Environmental  Laws before such agreement
can be reached,  Purchaser  and Seller shall reach  agreement on  communications
with the government  agency and the scope of the plan or project,  and Purchaser
shall  not agree to a site  assessment  or  remediation  plan  without  Seller's
consent.

     (g) If Purchaser's  share of Baseline  Corrective  Action Costs reaches the
$200 Million Cap, Seller shall have the right, but not the obligation, to assume
control over all further Baseline  Corrective  Action, the cost for which Seller
is responsible  under this  Agreement,  upon giving  Purchaser  ninety (90) days
prior written notice.  Within a reasonable period of time following such notice,
Purchaser and Seller shall agree upon an orderly transition of control over such
Baseline  Corrective  Action,  including,  but not limited to,  compensation for
equipment  previously used by Purchaser in connection  with Baseline  Corrective
Action.

     6. CASHOUT OF CERTAIN BASELINE CORRECTIVE ACTION OBLIGATIONS.  Seller shall
have the option to extinguish its share of Baseline  Corrective Action Costs for
a 76 Asset in exchange for an agreed lump-sum payment to Purchaser upon the sale
of a 76 Asset owned by Purchaser.  Designation  of such a 76 Asset shall be made
by written  notice to Purchaser.  Purchaser  and Seller shall  negotiate in good
faith in an attempt to agree on the appropriate  lump-sum payment.  In the event
the parties are unable to agree on the lump-sum  payment,  Seller shall have the
option to submit the matter for dispute  resolution in  accordance  with Section
10.  Upon  payment of the agreed  upon  amount or the amount  determined  by the
Independent Consultant to be appropriate,  Seller shall be released by Purchaser
from any further  environmental  obligation with respect to Baseline  Corrective
Action for such a 76 Asset and shall be entitled to indemnification by Purchaser
pursuant to section 8(b)(vi).  Only Purchaser's share of the projected  Baseline
Corrective  Action  Costs used in  determining  the  lump-sum  payment  shall be
included  at that  time in  calculating  the  $200  Million  Cap and  shall  not
otherwise  be included in  calculating  the  allocation  of Baseline  Corrective
Action Costs pursuant to Section 4(a).


                                       8


     7. ACCESS.

     (a) Upon reasonable  notice,  Purchaser  shall permit,  under the following
conditions  specified  in this  Section,  access to and entry upon a 76 Asset to
Seller  and  Seller's  independent  contractors  as  necessary:  (i) to  conduct
Baseline  Corrective  Action, if Seller elects to assume control of such action;
and (ii) to observe and monitor Baseline Corrective Action.

     (b) If Seller assumes control of Baseline Corrective Action,  except in the
event of an  emergency,  Seller shall provide  Purchaser  with at least five (5)
business days notice prior to  commencement  of any drilling,  construction,  or
equipment  installation,  and any other activity that may  unreasonably  disrupt
normal business operations at a 76 Asset. If any such activity will likely cause
an unreasonable disruption, Seller shall reschedule the activity to a reasonable
mutually  convenient time in order to minimize the  disruption.  Purchaser shall
not  unreasonably  interfere  with Seller while Seller  exercises  its rights of
ingress  and egress to conduct  Baseline  Corrective  Action.  Seller  shall use
reasonable  efforts  to conduct  Baseline  Corrective  Action in a manner  which
minimizes disruption to the business activities at a 76 Asset. Seller shall take
steps  reasonably  necessary to prevent  injury to persons or damage to property
resulting from or in any way connected with such Baseline  Corrective  Action it
conducts, including adherence to Purchaser's safety rules and procedures.

     (c)  Within a  reasonable  period  of time  after  completion  of  Baseline
Corrective Action at a 76 Asset where Seller has assumed control of such action,
Seller shall restore such 76 Asset to substantially  the condition which existed
immediately  prior to Seller's  commencement of Baseline  Corrective  Action. No
claim for special,  exemplary,  consequential or indirect  damages,  or for lost
profits,  shall be asserted  by  Purchaser  against  Seller in  connection  with
Baseline  Corrective  Action performed by an independent  contractor.  Purchaser
shall  have the right to pursue  such  damage  claims  against  the  independent
contractor. No contractor, subcontractor,  materialman, agent, officer, director
or employee of Seller  shall have any right to a lien  against a 76 Asset or any
part  thereof  for any work,  labor or  materials  furnished  to Seller  for the
actions performed thereon, unless otherwise required by applicable law.

     (d)  Purchaser  shall  reimburse  Seller for all  damages,  losses,  costs,
penalties,  fines and assessments  which Seller incurs if reasonable access to a
76 Asset is not granted to Seller in accordance with this  Agreement.  Purchaser
shall reimburse  Seller for any  out-of-pocket  damages in excess of $1,000 that
Purchaser  and its  employees,  agents,  lessees,  occupants  of a 76  Asset  or
contractors  cause,  as a  result  of  injury  to any test or  monitoring  well,
remediation  equipment  and/or  associated  piping,  or any  other  property  or
equipment  installed or otherwise used by Seller in connection with its Baseline
Corrective  Action  ("Remediation   Equipment"),   but  no  claim  for  special,
exemplary,  consequential  or  indirect  damages,  or for lost  profit  shall be
asserted by Seller in connection  therewith against Purchaser.  However,  Seller
shall  have the right to pursue  such  damage  claims  against  any  independent
contractor.  All Remediation Equipment owned by Seller shall remain the property

                                       9


of Seller  and may be  removed  from a 76 Asset,  upon  completion  of  Baseline
Corrective Action at a 76 Asset.

     8. INDEMNIFICATION.

     (a)  SELLER'S  INDEMNIFICATION:  Seller  shall  indemnify,  defend and hold
harmless  Purchaser  from and  against:  (i) subject to Section  4(a),  Baseline
Corrective Action Costs;  (ii) Compliance Action Costs,  except for that portion
of such costs to be paid by Purchaser  pursuant to Section 4(c); (iii) migration
of a Hazardous Substance after the Closing which would not have occurred but for
Baseline  Corrective  Action  conducted by Seller in a manner which  constitutes
gross negligence or willful  misconduct;  (iv) subject to Section 10, any damage
resulting  from any  inaccuracy in any  representation  or warranty of Seller in
this  Agreement;  (v)  Retained  Environmental  Liabilities;  and (vi) any other
obligations  for  which  Seller  has  assumed  responsibility  pursuant  to this
Agreement.

     (b) PURCHASER'S INDEMNIFICATION: Purchaser shall indemnify, defend and hold
harmless Seller from and against: (i) Corrective Action costs resulting from the
ownership or operation of the 76 Assets by Purchaser after the Closing which are
not included in Baseline  Corrective  Action  Cost;  (ii)  Purchaser's  share of
Baseline  Corrective  Action Costs as provided in Section 4(a); (iii) Compliance
Action  Costs  resulting  from the  ownership  or  operation of the 76 Assets by
Purchaser as provided in Section 4(c);  (iv) migration of a Hazardous  Substance
after the Closing  which would not have  occurred  but for  Baseline  Corrective
Action conducted by Purchaser in a manner which  constitutes gross negligence or
willful misconduct;  (v) all Baseline Corrective Action Costs incurred more than
twenty-five  (25) years after the Closing,  except as provided in Section  4(a);
(vi)  subject to Section 10, any damage  resulting  from any  inaccuracy  in any
representation  or warranty of Purchaser in this Agreement;  and (vii) any other
obligations  for which  Purchaser  has assumed  responsibility  pursuant to this
Agreement.

     (c) INDEMNIFICATION PROCEDURES.

                 Whenever  Purchaser  or Seller  becomes  aware of a claim  with
respect  to  a  76  Asset  ("Indemnified  Party")  for  which  the  other  party
("Indemnifying Party") is obligated to provide indemnification, the Indemnifying
Party shall,  within a reasonable  period of time, give prompt notice thereof (a
"Claim Notice"),  together with copies of written  information  relating to such
claim, and shall have the right to assume  responsibility  for the obligation to
be indemnified. Unless within twenty (20) days after such notice is given to the
Indemnifying Party, the Indemnifying Party gives the Indemnified Party notice of
its election to assume the obligation, the Indemnifying Party shall be deemed to
have  waived  such  right.  If the  Indemnifying  Party  elects to  assume  such
obligation,  (i) the Indemnifying  Party shall take such action as is reasonably
necessary to protect the Indemnified Party and (ii) the Indemnifying  Party will
keep the Indemnified Party fully advised as to such actions. If the Indemnifying
Party elects to assume responsibility for the obligation to be indemnified,  the
Indemnified  Party may take action that is  reasonably  necessary  to protect it
fully.

                                       10



     9. UST FUNDS.

          (a) Reimbursement claims have been and will continue to be
submitted to the California Petroleum  Underground Storage Tank Cleanup Fund and
similar  federal,  state  and  local  government  funds  ("UST  Funds")  to seek
reimbursement  of Corrective  Action costs.  Purchaser and Seller shall have the
right to pursue,  control,  settle,  waive or release  reimbursement claims they
have  filed with the UST Funds and for which  they have paid  Corrective  Action
costs. Any reimbursement  claim not on file as of the Closing shall be filed and
pursued by Seller, if Corrective Action is commenced prior to the Closing.

     (b) Seller shall have the right to any reimbursement amount received from a
UST Fund as a result of  Corrective  Action  costs  incurred by Seller at a Real
Property prior to the Closing.

     (c) Purchaser  shall have the right to any  reimbursement  amount  received
from a UST Fund as a result of Corrective  Action costs incurred by Purchaser at
a Real  Property  after the Closing,  but such amount  shall reduce  Purchaser's
share  of the  aggregate  Baseline  Corrective  Action  Costs  for  purposes  of
calculating the $200 Million Cap.

     (d) Purchaser and Seller shall  cooperate with each other in the filing and
pursuit of their respective  reimbursement  claims. In the event of a dispute as
to whether a particular  reimbursement claim should be submitted by Purchaser or
Seller,  Seller shall have the right to submit such claim pending  resolution of
the dispute in accordance with the dispute resolution  provisions of Section 10.
If  Purchaser  is  determined  to have the  right to such  claim,  Seller  shall
promptly  transfer control of the claim and execute any necessary  authorization
in favor of  Purchaser.  Purchaser and Seller shall pay their  respective  costs
associated with the submission and pursuit of any reimbursement claim.

     10. DISPUTE RESOLUTION AND LIMITATIONS OF LIABILITY.

     (a)  Purchaser and Seller agree that any disputed  claim or demand  against
the other  arising  out of or relating  to this  Agreement  shall be resolved in
accordance with and subject to the procedures and limitations of Section 10.

     (b) If a dispute  arises  between the parties under this Agreement and that
dispute is not  resolved  within a reasonable  period of time,  either party may
notify the other in writing that the dispute is to be submitted to  arbitration.
Such  arbitration  shall be held in Los Angeles,  California.  The parties shall
jointly select an  environmental  consultant,  engineer,  or other  professional
reasonably  qualified (including at least 7 years' experience in the appropriate
environmental field) to arbitrate such dispute  ("Independent  Consultant").  If
the Independent Consultant is not an attorney, he or she shall have the right to
obtain the assistance of qualified legal counsel in arbitrating the dispute,  if
the  Independent  Consultant  determines  that  such  assistance  is  necessary.
Notwithstanding  any other provision  hereof,  the parties shall each bear their

                                       11


respective  legal fees and costs,  and  one-half of the cost of the  Independent
Consultant (and his or her attorney, if necessary).  If the parties cannot agree
on the Independent  Consultant within sixty (60) days, either party may apply to
the American  Arbitration  Association in Los Angeles for the appointment of the
Independent Consultant.  The Independent Consultant shall establish an expedited
procedure for hearing and resolving the dispute. Each party shall have the right
to conduct  discovery  pursuant to California  Code of Civil  Procedure  section
1283.05 within sixty (60) days of the appointment of the Independent Consultant.
Unless the parties agree otherwise,  the Independent  Consultant  shall, no more
than one hundred twenty (120) days after the Independent Consultant is retained,
render a decision  resolving  the dispute,  with a written  opinion  stating the
reasons therefor.  The decision of the Independent Consultant shall be final and
binding,  and a court of  competent  jurisdiction  may enter  judgment  thereon.
Except  as  otherwise  provided  in  Section  10(c),  (d) and (e),  the  dispute
resolution  procedures of this Section 10 shall  constitute the exclusive remedy
of  the  parties  hereto  with  respect  to any  disputes  arising  out of  this
Agreement.

     (c) If a dispute arises between the parties prior to Closing concerning any
representation  in Section 2(a) or 3 under this Agreement,  the dispute shall be
limited by and resolved in accordance  with the  procedures set forth in Section
21 of the Sale and Purchase Agreement.

     (d) Notwithstanding Section 23(b) of the Sale and Purchase Agreement,  each
claim against Seller after Closing for breach of representation shall be subject
to the de minimis threshold provisions of Section 23(c) of the Sale and Purchase
Agreement and shall be aggregated  with all other claims subject to such Section
for purposes of calculating the $10 million threshold.

     (e)  Seller's  and  Purchaser's   representations  in  Sections  2  and  3,
respectively, and all liability with respect thereto, shall expire on the second
anniversary of the Closing.

     11. MISCELLANEOUS PROVISIONS.

     (a)  CONSTRUCTION.  This  Agreement  shall be governed by and  construed in
accordance with the laws of the State of California without giving effect to its
conflicts-of-laws principles.

     (b) ENTIRE  AGREEMENT.  This Agreement and the Schedules hereto  constitute
the entire  agreement among the parties  pertaining to the subject matter hereof
and supersedes all prior or contemporaneous  agreements  relating to the subject
matter  hereof.  In case of any conflict  between the body of this Agreement and
any such Schedule, the terms of the body of this Agreement shall prevail.


                                       12



     (c) ASSIGNMENT.

          (i)  Subject  to  Section  11(c)(ii),  this  Agreement  shall  not  be
     assigned,  in whole or in part,  without the prior  written  consent of the
     other party.

          (ii) Seller and Purchaser may each assign this Agreement,  in whole or
     in part, to one or more of their respective  affiliates,  upon prior notice
     to the non-assigning party; provided, however, that the non-assigning party
     may require as a condition  of such  assignment  that the  assigning  party
     reasonably demonstrate and/or assure the assignee's financial and technical
     capability to perform its obligations  hereunder.  Any attempted assignment
     of this Agreement in violation of this Section  11(c)(ii) shall be null and
     void.

          (iii) This  Agreement  shall  inure to the  benefit of, and be binding
     upon, the parties hereto and their respective heirs, legal representatives,
     successors and permitted assigns, except that any such assignment shall not
     relieve the assigning party of its obligations hereunder. This Agreement is
     not intended to, and does not create, any rights in any third parties.

     (d)  FURTHER  ASSURANCES.  Each  of the  parties  hereto  shall  take  such
additional  action,  and shall cooperate with one another,  as may be reasonably
necessary to effectuate the terms of this Agreement.

     (e) NOTICES.

          (i) All  written  notices  required or  permitted  to be given or made
     hereunder  shall be deemed to have  been  duly  given or made if  delivered
     personally, or sent by overnight courier delivery or by telecopy or similar
     facsimile transmission (and confirmed in writing thereafter),  or mailed by
     prepaid  registered or certified  mail,  return receipt  requested,  to the
     other  party at the  respective  address  set forth below (or to such other
     address as a party shall  designate  for itself by written  notice given or
     made in accordance herewith):

        (1) if to Seller, to it at:

           Unocal Corporation
           2141 Rosecrans Avenue, Suite 4000
           El Segundo, California 90245

           Attn:           Neal E. Schmale
                           Chief Financial Officer
                           (310) 726-7621 (Phone)
                           (310) 726-7806 (Fax)

           cc:             Dennis P.R. Codon, Esq.
                           General Counsel
                           (310) 726-7651 (Phone)
                           (310) 726-7815 (Fax)

                                       13




           (2)      if to Purchaser, to it at:

           Tosco Corporation
           72 Cummings Point Road
           Stamford, Connecticut 06902

           Attn:           Wilber McClave III, Esq.
                           General Counsel
                           (203) 977-1001 (Phone)
                           (203) 964-3187 (Fax)

           cc:             Duane B. Bordvick
                           Vice President Environmental and External Affairs
                           Tosco Corporation
                           2300 Clayton Road
                           Suite 1100
                           (510) 602-4050 (Phone)
                           (510) 602-4018 (Fax)

          (ii) Any notice,  request or other  communication  hereunder  shall be
     deemed  delivered  and given or made on the seventh  business day after the
     date of mailing, if mailed by registered or certified mail, or on the first
     business day after the date of transmittal,  if sent by courier delivery or
     by telecopy or similar  facsimile  transmission  (and  confirmed in writing
     thereafter),  or on the first  business day after the date of delivery,  if
     delivered personally.

     (f)   COUNTERPARTS.   This  Agreement  may  be  executed  in  one  or  more
counterparts, each of which shall be deemed to be an original instrument.

     (g) WAIVER.  It is agreed that any party to this  Agreement may extend time
for  performance  by any other  party  hereto or waive  the  performance  of any
obligation  of  any  other  party  hereto  or  waive  any  inaccuracies  in  the
representations  and warranties of any other party, but any such waiver shall be
in writing,  unless a non-written waiver is expressly  permitted,  and shall not
constitute  or be  construed  as a waiver  of any other  obligation,  condition,
representation or warranty under this Agreement.

     (h)  AMENDMENTS.  This  Agreement  cannot be altered,  amended,  changed or
modified in any respect or particular  unless each such  alteration,  amendment,
change or  modification  shall have been agreed to by each of the parties hereto
and reduced to writing in its entirety and signed and delivered by each party.


                                       14


                 IN  WITNESS   WHEREOF,   the   parties   have   executed   this
Environmental Agreement as of the date first above written.


                                        UNION OIL COMPANY OF CALIFORNIA
                                        a California corporation



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

                                            Time:


                                        TOSCO CORPORATION
                                        a Nevada corporation



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

                                            Title: