Exhibit 10.36

                                  TAX AGREEMENT
                                     between
                                 VALHI, INC.
                                       and
                             NL INDUSTRIES, INC.

      AGREEMENT dated as of January 1, 2001 by and among Valhi, Inc. ("VHI"),  a
Delaware  corporation  having its principal  executive  offices at Three Lincoln
Centre, 5430 LBJ Freeway,  Suite 1700, Dallas,  Texas 75240, Contran Corporation
("Contran"),  a Delaware  corporation having its principal  executive offices at
Three Lincoln  Centre,  5430 LBJ Freeway,  Suite 1700,  Dallas,  TX 75240 and NL
Industries, Inc. ("NL"), a New Jersey corporation having its principal executive
offices at 16825 Northchase Drive, Suite 1200, Houston, Texas 77060.

      WHEREAS,  VHI and NL are eligible to file consolidated  returns of federal
income taxes and, subject to certain jurisdictional limitations, will be subject
to combined state and local tax reporting effective January 1, 2001;

      WHEREAS, VHI and NL wish to provide for the allocation of liabilities, and
procedures  to be followed,  with respect to federal  income taxes of NL and any
subsidiaries of NL and with respect to certain combined state and local taxes on
the terms of this Agreement.

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

      1.  Definitions.  As used in this Agreement,  the following terms have the
meanings set forth below:

            (a) Code:  The Internal  Revenue Code of 1986, as amended,  and with
      respect to any section thereof any successor provisions under such Code or
      any successor Code.

            (b) Combined  Foreign,  State and Local Taxes: For a taxable period,
      the  amount  of all  foreign,  state and local  taxes,  together  with all
      interest  and  penalties  with  respect  thereto,  for which  liability is
      computed (1) on the basis of a combined,  unitary or  consolidated  return
      (whether at the  initiative  of the tax  authority or of the taxpayer) and
      (2) by  reference  to one or more  members of the NL Group and one or more
      members of the VHI Group not included in the NL Group.

            (c) Contran  Corporation:  A Delaware corporation that is the common
      parent of a group of corporations  electing to file a consolidated federal
      income tax return.

            (d) Federal  Taxes:  All federal  income  taxes,  together  with all
      interest and penalties with respect thereto.



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            (e) VHI Group: VHI and those of its direct and indirect subsidiaries
      which join in the filing of a consolidated  federal income tax return with
      its common  parent,  Contran (the  "Contran Tax Group"),  as such Group is
      constituted  from time to time.  For  purposes of this  Agreement  (to the
      extent related to Combined Foreign,  State and Local Taxes), the term "VHI
      Group"  shall  include all direct and  indirect  subsidiaries  of VHI with
      reference to which Combined Foreign, State and Local Taxes are determined.

            (f) NL Group:  NL  Industries,  Inc.  and each  direct  or  indirect
      subsidiary  of NL which would be a member of an affiliated  group,  within
      the  meaning  of section  1504(a) of the Code,  of which NL was the common
      parent,  as such Group is  constituted  from time to time. For purposes of
      this Agreement (to the extent related to Combined Foreign, State and Local
      Taxes) , the  term "NL  Group"  shall  include  all  direct  and  indirect
      subsidiaries  of NL with reference to which Combined,  Foreign,  State and
      Local taxes are determined.

            (g) NL Group Tax Liability:  For a taxable period, the liability for
      Federal Taxes and Combined Foreign,  State and Local taxes, as applicable,
      that the NL Group  would have had if it were not a member of the VHI Group
      during such taxable period (or during any taxable  period prior  thereto),
      and instead filed a separate  consolidated  return for such taxable period
      (and during all prior taxable periods  beginning after December 31, 2000);
      provided,  however,  that for purposes of determining such liability for a
      taxable  period  all  tax  elections  shall  be  consistent  with  the tax
      elections made by Contran for such period. In making such tax elections it
      is understood the Contran  Corporation will make those tax elections which
      are  beneficial  to  the  Contran  Tax  Group  on  a  consolidated  basis.
      Nevertheless,  Contran  will  use its  best  efforts  in the case of those
      elections which affect the  computation of the NL Group Tax Liability,  to
      make  elections in a reasonable  manner so as to minimize the NL Group Tax
      Liability.

2.    Contran as Agent.  Contran shall be the sole agent for the NL Group in all
      matters relating to the NL Group Tax Liability. The NL Group shall not (a)
      terminate such agency or (b) without the consent of Contran,  participate,
      or  attempt to  participate,  in any  matters  related to the NL Group Tax
      Liability,  including,  but not limited to,  preparation  or filing of, or
      resolution  of  disputes,  protests  or audits with the  Internal  Revenue
      Service, state or local taxing authorities concerning, the Contran Group's
      consolidated returns of Federal Taxes, returns of Combined Foreign,  State
      and Local Taxes or the NL Group Tax Liability with respect thereto for any
      taxable  period  beginning  after  December 31,  2000.  The NL Group shall
      cooperate  fully in providing  Contran with all  information and documents
      necessary or desirable to enable Contran to perform its obligations  under
      this Section,  including  completion of Internal Revenue Service and state
      or local tax audits in  connection  with such NL Group Tax  Liability  and
      determination of the proper liability for such NL Group Tax Liability.


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3.       Liability for Taxes; Refunds.

            (a) VHI, as the common parent of the NL Group,  shall be responsible
      for, and shall pay to Contran or a taxing  authority,  as applicable,  the
      consolidated tax liability for the VHI Group and has the sole right to any
      refunds  received  from  Contran  or a taxing  authority,  as  applicable,
      subject to the provisions of Sections 5 and 6 of this Agreement.

            (b)  Notwithstanding  any other provision of this Agreement,  NL and
      each subsidiary of NL which is a member of the NL Group shall be severally
      liable to VHI for the NL Group Tax Liability.

            (c) NL shall  indemnify VHI and hold it and the VHI Group other than
      the NL Group, harmless from and against any deficiency in the NL Group Tax
      Liability that may be due to VHI.

            (d) VHI  shall  indemnify  NL and hold it and the NL Group  harmless
      from and against any Federal Taxes and Combined  Foreign,  State and Local
      Taxes attributable to the VHI Group or any other member of the Contran Tax
      Group,  other than the NL Group,  as such taxes are determined  under this
      and other tax sharing agreements.

      4. Tax  Returns.  VHI  shall  file on  behalf  of the NL Group any and all
federal,  foreign, state and local tax returns that are required as they pertain
to the NL Group Tax Liability. The NL Group, at VHI's request, shall join in any
applicable  consolidated  returns of Federal  Taxes and any  returns of Combined
Foreign,  State and Local  Taxes (for which  returns  have not been  theretofore
filed)  and  execute  its  consent  to each  such  filing  on any form as may be
prescribed  for such consent if such consent is required.  The decision of VHI's
Senior  Vice  President  (or any  other  officer  so  designated  by  VHI)  with
responsibility  for  tax  matters  shall,  subject  to the  provisions  of  this
Agreement, be binding in any dispute between VHI and the NL Group as to what tax
position  should be taken  with  respect  to any item or  transaction  of the NL
Group. The preceding sentence is limited to the tax positions that affect the NL
Group Tax  Liability  and the  combined  VHI Group and  Contran  Tax  Group.  In
addition,  VHI and members of the VHI Group,  including NL and members of the NL
Group,   shall  provide  each  other  with  such  cooperation,   assistance  and
information  as each of them may request of the other with respect to the filing
of any tax return,  amended return,  claim for refund or other document with any
taxing  authority.  NL shall be solely  responsible for all taxes due for the NL
Group with  respect to tax returns  filed by NL or a member of the NL Group that
are required to be filed on a separate company basis, independent of VHI.

      5. Payment of NL Group Tax Liability for Federal Taxes.  On or before each
date,  as  determined  under  section  6655  of  the  Code,  for  payment  of an
installment of estimated  Federal Taxes,  NL shall pay to VHI an amount equal to
the  installment  which  the NL Group  would  have  been  required  to pay as an
estimated  payment of Federal Taxes to the Internal  Revenue  Service if it were
filing a separate  consolidated return in respect of the NL Group Tax Liability.
Any balance owed with

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respect to the NL Group Tax Liability  for such taxable  period shall be paid to
VHI on or before the 15th day of the third month after the close of such taxable
period.  If it is not  possible to  determine  the amount of such  balance on or
before such day, (a) a reasonable  estimate  thereof  shall be paid on or before
such day,  (b) the  amount of such  balance  shall be finally  determined  on or
before the  earlier  of; (i) the 15th day of the ninth  month after the close of
such  taxable  period  and (ii) the date on which the  consolidated  tax  return
containing  the NL Group for such  period  is filed  with the  Internal  Revenue
Service,  and (c) any  difference  between  the  amount  so  determined  and the
estimated  amount paid shall;  (i) in the case of an  underpayment,  be promptly
paid to VHI and (ii) in the case of an  overpayment,  be  promptly  refunded  or
applied  against  the  estimated  NL Group  Tax  Liability  for the  immediately
following tax period, at the option of VHI. If the overpayment is not applied to
the  immediately  following  tax  period,  such  overpayment  shall be  promptly
refunded to the NL Group. As between the parties to this Agreement, the NL Group
shall be solely  responsible  for the NL Group Tax  Liability  and shall have no
responsibility  for Federal  Taxes of the VHI Group or the  Contran  Group other
than payment of the NL Group Tax Liability in accordance  with the terms of this
Agreement.

      6.  Refunds for NL Group  Losses and Credits  for  Federal  Taxes.  If the
calculation with respect to the NL Group Tax Liability for Federal Taxes results
in a net operating  loss ("NOL") for the current tax period that, in the absence
of a Code Section 172(b)(3) election made by Contran, is carried back under Code
Sections 172 and 1502 to a prior taxable  period or periods of the NL Group with
respect to which the NL Group  previously  made  payments to VHI,  then, in that
event,  VHI shall pay (or credit) NL an amount  equal to the tax refund to which
the NL  Group  would  have  been  entitled  had the NL  Group  filed a  separate
consolidated  federal  income tax return for such year (but not in excess of the
net aggregate  amount of the NL Group Tax Liability  paid to VHI with respect to
the preceding two taxable  periods).  If the calculation  with respect to the NL
Group Tax Liability  results in an NOL for the current tax period,  that subject
to the Code  Section  172(b)(3)  election  made by Contran,  is not carried back
under Code Sections 172 and 1502 to a prior taxable  period or periods of the NL
Group  with  respect to which NL made  payments  to VHI or is not  carried  back
because the Contran Tax Group does not have a  consolidated  net operating  loss
for the  current  tax  period,  then,  in that  event  such NOL  shall be an NOL
carryover to be used in computing the NL Group Tax Liability for future  taxable
periods,  under the law  applicable to NOL  carryovers  in general,  as such law
applies to the relevant taxable period.  Furthermore, if the NL Group would have
been entitled to a refund of Federal Taxes for any year had the NL Group filed a
separate  consolidated  federal  income  tax  return  for the loss  year and the
carryback year, VHI shall pay to NL the amount which NL would have received as a
refund from the Internal Revenue Service. Payments made pursuant to this Section
6 shall be made on the date that Contran (or any  successor  common  parent of a
tax group to which the VHI Group is a  member)  files its  consolidated  federal
income tax return for the taxable period involved.  Principles  similar to those
discussed in this Section 6 shall apply in the case of the utilization of all NL
Group loss and credit carrybacks and carryovers.


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      7. Payment of NL Group Tax Liability  for Foreign,  State and Local Taxes.
The  foregoing  principles  contained in Sections 5 and 6 shall apply in similar
fashion to any consolidated or combined foreign, state or other local income tax
returns,  containing  any member of the VHI Group and any member of the NL Group
that is not also a member of the VHI Group, which may be filed.

       8. Subsequent  Adjustments.  If any settlement with the Internal  Revenue
 Service,  foreign,  state or local tax  authority or court  decision  which has
 become final results in any adjustment to any item of income,  deduction,  loss
 or credit to the VHI Group in respect  of any  taxable  period  subject to this
 Agreement,  which, in any such case, affects or relates to any member of the NL
 Group as constituted  during such taxable  period,  the NL Tax Group  Liability
 shall be  redetermined to give effect to such adjustment as if it had been made
 as  part  of or  reflected  in the  original  computation  of the NL Tax  Group
 Liability and proper  adjustment of amounts paid or owing  hereunder in respect
 of such liability and allocation shall be promptly made in light thereof.

      9.  Amendments.  This  Agreement may be amended,  modified,  superseded or
cancelled,  and any of the terms, covenants, or conditions hereof may be waived,
only by a  written  instrument  specifically  referring  to this  Agreement  and
executed by both  parties  (or, in the case of a waiver,  by or on behalf of the
party waiving  compliance).  The failure of either party at any time or times to
require performance of any provision of this Agreement shall in no manner affect
the right at a later time to enforce the same.  No waiver by either party of any
condition,  or of  any  breach  of any  term  or  covenant,  contained  in  this
Agreement, in any one or more instances, shall be deemed to be or construed as a
further or continuing waiver of any such condition or breach, or a waiver of any
other condition or of any breach of any other term or covenant.

      10. Retention of Records.  VHI shall retain all tax returns,  tax reports,
related  workpapers and all schedules  (along with all documents that pertain to
any such tax returns,  reports or workpapers) that relate to a taxable period in
which the NL Group is included  in a  consolidated  or combined  tax return with
VHI. VHI shall make such  documents  available to NL at NL's request.  VHI shall
not dispose of such documents without the permission of NL.

      11.  Headings.  The  headings of this  Agreement  are for  convenience  of
reference only, and shall not in any way affect the meaning or interpretation of
this Agreement.

      12.  Governing  Law.  This  Agreement  shall be construed  and enforced in
accordance with the laws of the State of Delaware without regard to conflicts of
laws provisions.

      13. Counterparts. This Agreement may be executed in multiple counterparts,
each of which shall be an original,  but all of which shall  constitute  but one
agreement.

      14.  Successors.  This  Agreement  shall be binding  upon and inure to the
benefit of the  parties  hereto  and their  respective  subsidiaries,  and their
respective successors and assigns.

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      15.  Effective  Date.  This Agreement  shall be effective as of January 1,
2001.


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      IN WITNESS WHEREOF, the parties hereto have executed this Agreement on the
  date first above written.

                                       VALHI, INC.


                                       By:
                                                /s/ William J. Lindquist
                                                --------------------------------
                                                William J. Lindquist
                                                Senior Vice President
[Seal]

ATTEST:




                               CONTRAN CORPORATION


                                       By:
                                                /s/ William J. Lindquist
                                                --------------------------------
                                                William J. Lindquist
                                                Senior Vice President
[Seal]

ATTEST:





                               NL INDUSTRIES, INC.


                                       By:
                                                /s/ Robert D. Hardy
                                                --------------------------------
                                                Robert D. Hardy
                                                Vice President and Controller


ATTEST:




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