Document:

INTERCORPORATE SERVICES AGREEMENT

                                     BETWEEN

                               CONTRAN CORPORATION

                                       AND

                             KRONOS WORLDWIDE, INC.

                         Dated as of October [__], 2003

<PAGE>

                                TABLE OF CONTENTS
                                                                          Page

Recitals....................................................................1

ARTICLE I.  RETENTION OF CONTRAN............................................1

         Section 1.1.  Performance of Services..............................1
         Section 1.2.  Disclaimer, Limited Liability; Indemnification.......2

ARTICLE II.  SERVICES.......................................................2

         Section 2.1.  Provision of Financial, Audit,
                        Accounting and Tax Services.........................2
         Section 2.2.  Provision of Other Services..........................2

ARTICLE III.  COMPENSATION..................................................3

         Section 3.1.  Compensation for Services............................3

ARTICLE IV.  CONFIDENTIALITY................................................3

         Section 4.1.  Confidentiality......................................3
         Section 4.2.  Tax Information......................................4

ARTICLE V.  MISCELLANEOUS...................................................4

         Section 5.1.  Review by KWI........................................4
         Section 5.2.  Maintenance and Inspection of Records................4
         Section 5.3.  Indemnity............................................4
         Section 5.4.  Notices..............................................4
         Section 5.5.  Term; Renewal........................................5
         Section 5.6.  Independent Contractor...............................5
         Section 5.7.  Force Majeure........................................5
         Section 5.8.  Entire Agreement.....................................6
         Section 5.9.  Amendments...........................................6
         Section 5.10.  Severability........................................6
         Section 5.11.  Counterparts........................................6
         Section 5.12.  Successors and Assigns..............................6
         Section 5.13.  Governing Law.......................................6
         Section 5.14.  Submission to Jurisdiction; Service; Waivers........6
         Section 5.15.  No Third-Party Beneficiaries........................7
         Section 5.16.  Titles and Headings.................................7

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                        INTERCORPORATE SERVICES AGREEMENT

     This  Intercorporate  Services  Agreement  ("Agreement"),  is entered  into
effective as of October  [__],  2003 (the  "Effective  Date"),  between  Contran
Corporation,  a Delaware corporation ("Contran"),  and Kronos Worldwide, Inc., a
Delaware corporation ("KWI").

                                    Recitals

     A. KWI is an indirectly held subsidiary of Contran.

     B. KWI is engaged in the manufacture,  sales, marketing and distribution of
titanium dioxide and associated products.

     C.  KWI has and  will  have the need  for  executive,  legal,  audit,  tax,
accounting,  treasury,  administrative,  financial, risk management,  technical,
consulting and similar services from time to time, but has determined that it is
not  cost  effective  to  obtain  and  separately  maintain  the  infrastructure
associated   therewith,   particularly   including  the  costs  associated  with
attracting and maintaining on its payroll on a full time basis a full complement
of skilled employees.

     D.  Contran is able and willing to provide the  foregoing  services to KWI,
and KWI desires to engage  Contran as an  independent  contractor to provide the
same in accordance with the terms set forth in this Agreement.

                                    Agreement

     For  and in  consideration  of the  mutual  promises,  representations  and
covenants herein contained, the parties hereto agree as follows.

                                   ARTICLE I.
                              RETENTION OF CONTRAN

     Section 1.1. Performance of Services.

          (a) KWI hereby engages and retains Contran to perform the services set
     forth in Article II (the  "Services") and Contran hereby accepts and agrees
     to provide such Services to KWI upon the terms and  conditions  hereinafter
     set forth.  All  Services  to be  provided  by Contran  hereunder  shall be
     performed at the request and under the  direction of KWI, and Contran shall
     not have any power to act  independently  on  behalf  of KWI other  than as
     specifically authorized hereunder or from time to time by KWI.

          (b) Contran shall  determine  the  corporate  facilities to be used in
     rendering the Services and the individuals who will render such Services.

                                       -1-
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          (c) Contran will use reasonable efforts to make the Services available
     with  substantially the same degree of care as it employs in making similar
     services available for its own operations.

          (d) Those employees or agents of Contran who perform similar  services
     for Contran or for other  affiliates of Contran,  or both, will perform the
     Services.

          (e)  Nothing  herein  shall  be  deemed  to  restrict  Contran  or its
     directors,  officers, employees or agents from engaging in any business, or
     from contracting with other parties, including,  without limitation,  other
     affiliates of Contran, for similar or different services.

     Section 1.2. Disclaimer, Limited Liability; Indemnification.

          (a) Contran makes no express or implied representations, warranties or
     guarantees  relating  to the  Services  or the  quality  or  results of the
     Services to be performed under this Agreement.

          (b) Contran, its officers,  employees or agents shall not be liable to
     KWI or any third party,  including any governmental agency, for any claims,
     losses,  damages  or  expenses  that may  result  from the  manner in which
     Contran,  its  officers,  employees  or agents  render the  Services or the
     consequences   of  any  failure  or  delay  to  perform  any  of  Contran's
     obligations  under this Agreement,  other than claims,  damages or expenses
     arising from Contran's gross  negligence or willful or reckless  misconduct
     (collectively,  "Claims").  KWI shall have the ultimate  responsibility for
     all Services.

          (c) KWI shall  indemnify and hold Contran  harmless  from Claims.  KWI
     shall indemnify and hold Contran's  officers,  employees or agents harmless
     from Claims to the full extent that  Contran  could  indemnify  such person
     under  applicable  law in  effect  from  time to time.  KWI  shall  advance
     expenses  as incurred by Contran or its  officers,  employees  or agents in
     connection with KWI's indemnification obligations under this Agreement.

                                   ARTICLE II.
                                    SERVICES

     Section 2.1.  Provision of Financial,  Audit,  Accounting and Tax Services.
During the term of this  Agreement,  Contran  shall  provide  financial,  audit,
accounting  and  tax  services,  including  without  limitation,  operation  and
administration of tax compliance, for KWI's operations in the ordinary course of
business.

     Section  2.2.  Provision  of  Other  Services.  During  the  term  of  this
Agreement,  at  the  request  of  KWI,  Contran  shall  provide  administrative,
executive,  legal, risk management,  treasury,  technical,  consulting and other

                                       -2-
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services  required by KWI from time to time. KWI may request such other services
from time to time, including, without limitation, the following:

          (a) executive and managerial functions;

          (b)    administration   of   KWI's   insurance    policies   including
     administration of worker's compensation claims;

          (c) treasury functions, bank negotiations, compliance matters; and

          (d) legal advice and compliance reporting.

                                  ARTICLE III.
                                  COMPENSATION

     Section 3.1.  Compensation for Services.  Contran and KWI shall on or prior
to the Effective Date and before the beginning of each subsequent calendar year,
agree on the budgeted amounts of reimbursable costs and the allocation method to
be applied for such year.  Such  allocation  method may be revised  from time to
time with the consent of both parties.

          (a) KWI shall pay to Contran one fourth of the budgeted  annual amount
     in advance quarterly around the first business day of each quarter.

          (b) From time to time,  the budgeted  amounts may be revised to better
     reflect  actual  expenses,  and  adjusted  billings  will then be made from
     Contran to KWI.

          (c) All charges  from  Contran to KWI are  intended to be equal to the
     actual cost of such expenses without premium or mark-up to Contran.

                                   ARTICLE IV.
                                 CONFIDENTIALITY

     Section  4.1.  Confidentiality.  Each party  shall hold and shall cause its
directors,    officers,    employees,    agents,    consultants   and   advisors
("Representatives") to hold in strict confidence all information (other than any
such  information  relating solely to the business or affairs of such party that
is otherwise publicly known or available)  concerning the other party unless (i)
such  party  is  compelled  to  disclose   such   information   by  judicial  or
administrative  process or, in the opinion of its counsel, by other requirements
of law or (ii)  such  information  can be shown to have  been (A) in the  public
domain  through  no  fault  of  such  party  or  (B)  lawfully   acquired  on  a
non-confidential basis from other sources.  Notwithstanding the foregoing,  such
party may  disclose  such  information  to its  Representatives  so long as such

                                       -3-
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persons  are  informed  by  such  party  of  the  confidential  nature  of  such
information   and  are  directed  by  such  party  to  treat  such   information
confidentially.  If such  party or any of its  Representatives  becomes  legally
compelled to disclose any documents or information  subject to this Section 4.1,
such party will promptly notify the other party so that the other party may seek
a protective  order or other remedy or waive such party's  compliance  with this
Section 4.1. If no such  protective  order or other remedy is obtained or waiver
granted, such party will furnish only that portion of the information that it is
advised by counsel is legally required and will exercise its reasonable  efforts
to obtain adequate  assurance that confidential  treatment will be accorded such
information.  Such party agrees to be responsible for any breach of this Section
4.1 by it and its Representatives.

     Section 4.2. Tax Information.  Notwithstanding anything set forth herein to
the contrary  (including Section 4.1) or in any other agreement to which a party
hereto is bound, the parties hereto (and any employee,  representative  or other
agent of any of the parties)  are hereby  expressly  authorized  to disclose all
information  relating to taxes as required by the Internal Revenue Code of 1986,
as amended or  supplemented,  and the  regulations  promulgated  thereunder (the
"Code"), but only to the extent necessary to comply with the Code.

                                   ARTICLE V.
                                  MISCELLANEOUS

     Section 5.1. Review by KWI. All reports,  memoranda,  returns,  statements,
contracts,  agreements,  regulatory  submissions,  applications  and  any  other
documents  arising from or in  connection  with the Services for or on behalf of
KWI shall be subject to review and approval by KWI.

     Section 5.2.  Maintenance  and  Inspection  of Records.  Contran shall keep
accurate  books and records with  respect to the costs and expenses  incurred in
connection  with the Services and such other books,  accounts and records of its
operations as may be reasonably  necessary for purposes of this  Agreement.  KWI
shall be permitted to inspect such books and records at any reasonable time.

     Section  5.3.  Indemnity.  KWI assumes  all  liability  for,  and agrees to
defend,  indemnify  and  hold  Contran,  its  employees,   officers,  directors,
shareholders  and agents,  harmless  from and against all demands,  liabilities,
damages,  costs and  expenses,  including  attorneys'  and expert  witness  fees
("Loss"),  incurred by Contran  arising from or in connection with the Services,
other than any Loss  caused by the gross  negligence  or willful  misconduct  of
Contran.

     Section 5.4. Notices. All notices and other communications  hereunder shall
be in  writing,  and  shall be  delivered  by hand or mailed  by  registered  or
certified  mail (return  receipt  requested) or  transmitted by facsimile to the
parties at the following  addresses  (or at such other  addresses for a party as
shall be  specified  by like  notice)  and shall be deemed  given on the date on
which such notice is received:

         If to Contran:             Contran Corporation.
                                    Three Lincoln Centre

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                                    5430 LBJ Freeway, Suite 1700
                                    Dallas, Texas   75240-2697
                                    Attention:  General Counsel
                                    Phone:  972.450.4251
                                    Fax:  972.448.1445

         If to KWI:                 Kronos Worldwide, Inc.
                                    Three Lincoln Centre
                                    5430 LBJ Freeway, Suite 1700
                                    Dallas, Texas   75240-2697
                                    Attention:  General Counsel
                                    Phone:  972.450.4289
                                    Fax:  972.448.1445

     Section  5.5.  Term;  Renewal.  The initial  term of this  Agreement  shall
commence as of the  Effective  Date and end on December 31,  2003,  but shall be
automatically  renewed  for  successive  terms of one  year.  Either  party  may
terminate  this  Agreement by giving  written notice of termination to the other
party not less than sixty (60) days prior to the end of the then  current  term.
In  addition,  in the event of a  material  default  hereunder  by a party,  the
non-defaulting  party may terminate  this  Agreement upon thirty (30) days prior
written notice if such default remains uncured and is continuing for twenty (20)
days after receipt by the  defaulting  party of such written notice of intent to
terminate.  A final  accounting  and  payment  by one  party to the other of all
amounts  payable  hereunder  shall be made  pursuant to the terms hereof  within
thirty (30) days following such termination.

     Section  5.6.  Independent  Contractor.  Contran  shall  be an  independent
contractor and not an employee of, or partner or joint venture with, KWI.

     Section 5.7. Force Majeure.  No party shall be in default of this Agreement
or liable to the other  party for any  delay or  default  in  performance  where
occasioned by any cause of any kind or extent beyond its control,  including but
not limited to,  armed  conflict or economic  dislocation  resulting  therefrom;
embargoes;   shortages  of  labor,  raw  materials,   production  facilities  or
transportation;  labor difficulties;  civil disorders of any kind; action of any
civil or military authorities  (including,  priorities and allocations);  fires;
floods and accidents.  The dates on which the obligations of the party are to be
fulfilled shall be extended for a period equal to the time lost by reason of any
delay arising, directly or indirectly from:

          (a) Any of the foregoing causes, or

          (b) Inability of a party,  as a result of causes beyond its reasonable
     control,  to obtain instruction or information from the other party in time
     to perform its obligations by such dates.

                                       -5-
<PAGE>

     Section  5.8.  Entire  Agreement.  This  Agreement  constitutes  the entire
understanding  between the parties with respect to the subject matter hereof and
all prior  agreements  or  understandings  shall be  deemed  merged  herein.  No
representations,  warranties and if  certifications,  express or implied,  shall
exist as between the parties except as stated herein.

     Section 5.9.  Amendments.  No amendments,  waivers or modifications  hereof
shall be made or deemed to have been made  unless in  writing,  executed  by the
party to be bound thereby.

     Section  5.10.  Severability.  If any  provision  in this  Agreement or the
application  of such provision to any person or  circumstance  shall be invalid,
illegal or unenforceable,  the remainder of this Agreement or the application of
such provision to persons or circumstances  other than those to which it is held
invalid, illegal or unenforceable shall not be affected thereby.

     Section 5.11. Counterparts. This Agreement may be executed in any number of
counterparts,  each of which when so executed  shall be deemed to be an original
and all of which when taken together shall constitute this Agreement.

     Section  5.12.   Successors  and  Assigns.  This  Agreement  shall  not  be
assignable,  in whole or in part,  directly or  indirectly,  by any party hereto
without the prior written consent of the other party hereto,  and any attempt to
assign any rights or  obligations  arising,  under this  Agreement  without such
consent shall be void.  This Agreement  shall be binding,  upon and inure to the
benefit of the parties  hereto and their  respective  successors  and  permitted
assigns.

     Section  5.13.  Governing  Law.  This  Agreement  shall be  governed by and
construed in accordance  with the domestic  laws of the state of Texas,  without
giving effect to any choice of law or conflict of law provision or rule (whether
of  the  state  of  Texas  or any  other  jurisdiction)  that  would  cause  the
application of the laws of any jurisdiction other than the state of Texas.

     Section 5.14. Submission to Jurisdiction; Service; Waivers. WITH RESPECT TO
ANY CLAIM ARISING OUT OF THIS AGREEMENT, EACH PARTY (A) IRREVOCABLY SUBMITS, FOR
ITSELF AND ITS  PROPERTY,  TO THE  JURISDICTION  OF THE FEDERAL OR STATE  COURTS
LOCATED IN DALLAS COUNTY,  TEXAS (B) AGREES THAT THE VENUE FOR ANY SUIT,  ACTION
OR PROCEEDING ARISING OUT OF OR RELATING TO THIS AGREEMENT SHALL BE EXCLUSIVE TO
SUCH COURTS, AND (C) IRREVOCABLY WAIVES ANY OBJECTION IT MAY HAVE AT ANY TIME TO
THE LAYING OF VENUE OF ANY SUIT, ACTION OR PROCEEDING ARISING OUT OF OR RELATING
TO THIS AGREEMENT BROUGHT IN ANY SUCH COURT,  IRREVOCABLY  WAIVES ANY CLAIM THAT
ANY SUCH SUIT,  ACTION OR PROCEEDING  BROUGHT IN ANY SUCH COURT HAS BEEN BROUGHT
IN AN INCONVENIENT FORUM AND FURTHER  IRREVOCABLY WITH THE RIGHT TO OBJECT, WITH

                                       -6-
<PAGE>

RESPECT TO SUCH CLAIM, SUIT, ACTION OR PROCEEDING BROUGHT IN ANY SUCH COURT THAT
SUCH COURT DOES NOT HAVE  JURISDICTION  OVER IT. EACH PARTY  HEREBY  IRREVOCABLY
CONSENTS TO THE SERVICE OF PROCESS IN ANY SUCH SUIT, ACTION OR PROCEEDING IN ANY
OF THE  AFORESAID  COURTS BY THE MAILING OF COPIES OF SUCH PROCESS TO THE PARTY,
BY CERTIFIED OR REGISTERED MAIL AT THE ADDRESS SPECIFIED IN SECTION 5.4.

     Section 5.15. No  Third-Party  Beneficiaries.  This Agreement is solely for
the benefit of the parties  hereto and should not be deemed to confer upon third
parties any remedy, claim,  liability,  reimbursement,  claim of action or other
right in excess of those existing without reference to this Agreement.

     Section 5.16.  Titles and Headings.  Titles and headings to sections herein
are inserted for convenience of reference only and are not intended to be a part
of or to affect the meaning or interpretation of this Agreement.

     Executed as of the Effective Date.

                             CONTRAN CORPORATION

                             By:
                                -----------------------------------------------
                                [Name, Title]

                             KRONOS WORLDWIDE, INC.

                             By:
                                ----------------------------------------------
                                [Name, Title]

                                       -7-PROMISSORY NOTE

$200,000,000.00                  October __, 2003                 Dallas, Texas

     FOR VALUE RECEIVED,  the undersigned,  Kronos  Worldwide,  Inc., a Delaware
corporation,  unconditionally  promises  to pay to the  order of NL  Industries,
Inc., a New Jersey corporation, in lawful money of the United States of America,
the principal sum of TWO HUNDRED MILLION and NO/100ths DOLLARS ($200,000,000.00)
together  with  interest  from the  date of this  Note on the  unpaid  principal
balance from time to time pursuant to the terms of this Note. This Note shall be
unsecured  and will bear  interest  on the  terms set forth in  Section 4 below.
Capitalized  terms not otherwise  defined shall have the meanings  given to such
terms in Section 14 of this Note.

     Section 1.Place of Payment. All payments will be made at Payee's address at
Three Lincoln Centre, 5430 LBJ Freeway, Suite 1700, Dallas, Texas 75240-2697, or
such other place as the Payee may from time to time  designate  in  writing,  in
immediately available funds, without setoff or counterclaim.

     Section 2. Payment.  The principal  balance of this Note and any unpaid and
accrued  interest  thereon shall be due and payable on the Maturity Date or upon
acceleration  as provided  herein.  Prior to the Maturity Date or  acceleration,
unpaid and accrued  interest on the outstanding  principal  balance of this Note
shall be due and  payable  quarterly  on March  31,  June 30,  September  30 and
December 31 of each year;  provided,  however,  that such day is a business day,
and if such day is not a business day, the quarterly  interest  payment shall be
due the next successive business day.

     Section 3.  Prepayment.  This Note may be prepaid in part or in full at any
time without penalty; provided,  however,  prepayments shall be first applied to
accrued and unpaid interest and then to principal.

     Section 4. Interest. The unpaid balance of this Note (exclusive of any past
due  principal)  shall bear interest at an annual rate of nine percent (9%). Ten
business days after the Maturity Date or  acceleration as provided in this Note,
all past due  principal  and past due  interest  owed  under this Note will bear
interest  at an annual rate of twelve  percent  (12%).  Accrued  interest on the
unpaid principal of this Note shall be computed on the basis of a 365 or 366-day
year, as the case may be, for actual days elapsed. In no event,  however,  shall
such  computation  result in an amount of accrued  interest  that  would  exceed
accrued interest on the unpaid  principal  balance during the same period at the
Maximum Rate.  Notwithstanding  anything to the contrary, this Note is expressly
limited so that in no contingency or event  whatsoever  shall the amount paid or
agreed  to be  paid  to  the  Payee  exceed  the  Maximum  Rate.  If,  from  any
circumstances  whatsoever,  the Payee  shall ever  receive as interest an amount
that would exceed the Maximum Rate, such amount received that would be in excess
of the Maximum Rate shall be applied to the  reduction  of the unpaid  principal
balance and not to the payment of interest,  and if the principal amount of this
Note is paid in full, any remaining  excess shall be paid to Maker,  and in such
event, the Payee shall not be subject to any penalties  provided by any laws for
contracting for, charging,  taking, reserving or receiving interest in excess of
the highest lawful rate permissible under applicable law.

     Section 5. Remedy.  Upon the occurrence and during the  continuation  of an
Event of Default,  Payee may, at its option, declare the entire unpaid principal
of this Note,  and all accrued  interest and other  amounts  payable  hereunder,
immediately due and payable without presentment, demand, protest or other notice
of any  kind,  all of which  are  expressly  waived  by  Maker,  and  upon  such
declaration, such amounts shall become and shall be immediately due and payable.
The Payee shall have all of the rights and remedies  provided in the  applicable
Uniform Commercial Code or in this Note or any other agreement between Maker and
in favor of the Payee,  as well as those  rights and  remedies  provided  by any
other  applicable law, rule or regulation.  All rights and remedies of the Payee
are cumulative and may be exercised singly or concurrently.  The exercise of any
right or remedy  will not be a waiver of any other  right or remedy.  Failure to
exercise any right or remedy upon the  occurrence  of an Event of Default  shall
not  constitute a waiver of the right to exercise  such right or remedy upon the
occurrence of a subsequent Event of Default.

     Section  6.  Right of  Offset.  The  Payee  shall  have the right of offset
against  amounts  that may be due by the  Payee  now or in the  future  to Maker
against amounts due under this Note.

     Section 7.  Record of  Outstanding  Principal.  The date and amount of each
repayment of principal outstanding under this Note shall be recorded by Payee in
its records.  The aggregate unpaid principal  balance so recorded by Payee shall
be the best evidence of the principal  balance owing and unpaid under this Note;

                                                                     Page 1 of 3
<PAGE>
so  recording  any  such  balance  shall  not  limit  or  otherwise  affect  the
obligations of Maker under this Note to repay the principal balance  outstanding
and all accrued or accruing interest.

     Section 8. Waiver. Maker and each surety,  endorser,  guarantor,  and other
party now or  subsequently  liable for  payment of this  Note,  severally  waive
demand, presentment for payment, notice of dishonor, protest, notice of protest,
diligence in  collecting or bringing suit against any party liable on this Note,
and further agree to any and all extensions,  renewals,  modifications,  partial
payments,  substitutions of evidence of indebtedness,  and the taking or release
of any collateral with or without notice before or after demand by the Payee for
payment under this Note.

     Section 9. Costs and  Attorneys'  Fees. In the event the Payee incurs costs
in collecting on this Note, this Note is placed in the hands of any attorney for
collection,  suit is filed on this Note or if proceedings are had in bankruptcy,
receivership,  reorganization,  or other legal or judicial  proceedings  for the
collection, Maker and any guarantor jointly and severally agree to pay on demand
to the Payee all expenses and costs of  collection,  including,  but not limited
to,  attorneys' fees incurred in connection with any such  collection,  suit, or
proceeding, in addition to the principal and interest then due.

     Section 10. Time of Essence.  Time is of the essence with respect to all of
Maker's obligations and agreements under this Note.

     Section  11.  Jurisdiction  and Venue.  This Note shall be  governed by and
construed in accordance  with the domestic  laws of the state of Texas,  without
giving effect to any choice of law or conflict of law provision or rule (whether
of  the  state  of  Texas  or any  other  jurisdiction)  that  would  cause  the
application of the laws of any jurisdiction other than the state of Texas. Maker
consents to jurisdiction in the courts located in Dallas, Texas.

     Section  12.  Notice.  Any notice or demand  required by this Note shall be
deemed to have been given and  received on the earlier of (i) when the notice or
demand is actually  received by the  recipient or (ii) 72 hours after the notice
is deposited in the United States mail,  certified or  registered,  with postage
prepaid, and addressed to the recipient. The address for giving notice or demand
under  this Note (i) to the Payee  shall be the place of  payment  specified  in
Section 1 or such other  place as the Payee may  specify in writing to the Maker
and (ii) to the Maker shall be the address  below the Maker's  signature or such
other place as the Maker may specify in writing to the Payee.

     Section 13.  Successors  and Assigns.  All of the  covenants,  obligations,
promises  and  agreements  contained in this Note made by Maker shall be binding
upon its successors and assigns;  notwithstanding the foregoing, Maker shall not
assign this Note or its  performance  under this Note without the prior  written
consent of the Payee.

     Section 14.  Definitions.  For purposes of this Note,  the following  terms
shall have the following meanings:

          (a) "Event of  Default"  shall mean the  failure by Maker to make when
     due a punctual  payment of  principal  of, or interest on, this Note within
     thirty (30) days  following the date such amount becomes due and payable in
     accordance with the terms of this Note.

          (b) "Maker" shall mean Kronos Worldwide, Inc., a Delaware corporation.

          (c) "Maturity Date" shall mean December 31, 2010.

          (d)  "Maximum  Rate"  shall mean the highest  lawful rate  permissible
     under applicable law for the use, forbearance or detention of money.

          (e) "Note" shall mean this Promissory Note.

                                                                     Page 2 of 3
<PAGE>

          (f) "Payee" shall mean NL Industries,  Inc., a New Jersey corporation,
     or subsequent holder of this Note.

                             MAKER:

                             KRONOS WORLDWIDE, INC.

                             Robert D. Graham, Vice President

                             Address:     Three Lincoln Centre
                                          5430 LBJ Freeway, Suite 1700
                                          Dallas, Texas   75240-2697

                                                                     Page 3 of 3

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