Exhibit 99.1



                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                    FORM 11-K


                 Annual Report Pursuant to Section 15(d) of the
                         Securities Exchange Act of 1934


|X|        Annual report  pursuant to Section 15(d) of the  Securities  Exchange
           Act of 1934 - for the year ended December 31, 1999

                                       or

|_|        Transition  report  pursuant  to  Section  15(d)  of  the  Securities
           Exchange Act of 1934 - for the transition period from       to

                          Commission file number 1-640


           A. Full title of the plan and the address of the plan,  if  different
from that of the issuer named below:

                               NL INDUSTRIES, INC.
                             RETIREMENT SAVINGS PLAN

           B. Name of issuer of the securities held pursuant to the plan and the
address of its principal executive office:

                               NL INDUSTRIES, INC.
                       16825 Northchase Drive, Suite 1200
                            Houston, Texas 77060-2544





<PAGE>



                               NL INDUSTRIES, INC.
                             RETIREMENT SAVINGS PLAN

                                      INDEX



                                                                       Page

Signature Page                                                           2

Financial Statements and Supplemental Schedules
 with Report of Independent Accountants                              F-1 to F-15

Exhibit I - Consent of Independent Accountants


                                      - 1 -

<PAGE>



                                    SIGNATURE


           Pursuant  to the  requirements  of the  Securities  Act of 1934,  the
Administrator has duly caused this Annual Report to be signed by the undersigned
thereunto duly authorized.


                                                    NL INDUSTRIES, INC.
                                                    RETIREMENT SAVINGS PLAN

                                          By:       NL INDUSTRIES, INC.
                                                    PENSION AND EMPLOYEE
                                                    BENEFITS COMMITTEE,
                                                    Administrator of
                                                    NL Industries, Inc.
                                                    Retirement Savings Plan


                                          By:       /s/ Robert D. Hardy
                                                    Robert D. Hardy
                                                    Chairman, Pension and
                                                    Employee Benefits Committee


June 27, 2000


                                      - 2 -

<PAGE>




                               NL INDUSTRIES, INC.
                             RETIREMENT SAVINGS PLAN



        FINANCIAL STATEMENTS, FUND INFORMATION AND SUPPLEMENTAL SCHEDULES
                     WITH REPORT OF INDEPENDENT ACCOUNTANTS

                                December 31, 1999



<PAGE>



                               NL INDUSTRIES INC.
                             RETIREMENT SAVINGS PLAN


                                      INDEX



                                                                        Page

Report of Independent Accountants                                       F-2

Financial Statements:
---------------------

 Statements of Net Assets Available for Benefits
  - December 31, 1998 and 1999                                           F-3

 Statements of Changes in Net Assets Available for Benefits with
  Fund Information - Years ended December 31, 1998 and 1999          F-4 to F-7

 Notes to Financial Statements                                       F-8 to F-13

Supplemental Schedules:
-----------------------

 Schedule of Assets Held for Investment Purposes
  at End of Year - December 31, 1999                                     F-14

 Schedule of Reportable Transactions -
  Year ended December 31, 1999                                           F-15


All other schedules are omitted because they are not applicable or not required.

                                       F-1

<PAGE>






                        REPORT OF INDEPENDENT ACCOUNTANTS


To the Pension and Employee Benefits Committee of
NL Industries, Inc.:

           In our opinion,  the accompanying  statements of net assets available
for benefits and the related  statements of changes in net assets  available for
benefits present fairly, in all material respects,  the net assets available for
benefits of the NL  Industries,  Inc.  Retirement  Savings  Plan (the "Plan") at
December 31, 1998 and 1999, and the changes in net assets available for benefits
for the years then ended in  conformity  with  accounting  principles  generally
accepted in the United States. These financial statements are the responsibility
of the Plan's  management;  our responsibility is to express an opinion on these
financial  statements  based on our  audits.  We  conducted  our audits of these
statements  in  accordance  with auditing  standards  generally  accepted in the
United  States,  which  require  that we plan and  perform  the  audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement.  An audit includes examining, on a test basis, evidence supporting
the  amounts  and  disclosures  in  the  financial  statements,   assessing  the
accounting  principles  used and significant  estimates made by management,  and
evaluating the overall  financial  statement  presentation.  We believe that our
audits provide a reasonable basis for the opinion expressed above.

           Our audits  were  conducted  for the purpose of forming an opinion on
the basic financial statements taken as a whole. The supplemental  schedules, as
listed on the  accompanying  index,  are presented for the purpose of additional
analysis and are not a required part of the basic  financial  statements but are
supplementary  information  required  by the  Department  of  Labor's  Rules and
Regulations for Reporting and Disclosure  under the Employee  Retirement  Income
Security Act of 1974.  The fund  information in the statements of changes in net
assets  available for benefits is presented for purposes of additional  analysis
rather than to present the changes in net assets  available for benefits of each
fund. These  supplemental  schedules and fund information are the responsibility
of the Plan's management.  The supplemental  schedules and fund information have
been  subjected  to the auditing  procedures  applied in the audits of the basic
financial  statements  and, in our  opinion,  are fairly  stated in all material
respects in relation to the basic financial statements taken as a whole.




                                              PricewaterhouseCoopers LLP
Houston, Texas
June 8, 2000

                                       F-2

<PAGE>



                               NL INDUSTRIES, INC.
                             RETIREMENT SAVINGS PLAN

                 STATEMENTS OF NET ASSETS AVAILABLE FOR BENEFITS

                           December 31, 1998 and 1999


<TABLE>
<CAPTION>

                                                        1998             1999
                                                    -----------      -----------

                ASSETS

<S>                                                 <C>              <C>
Investments at fair value:
  Common stock ...............................      $ 2,347,862      $ 2,429,229
  Other securities ...........................       23,406,941       23,331,334
Employer contributions receivable ............          598,532          307,458
Cash .........................................             --             36,427
                                                    -----------      -----------

  Net assets available for benefits ..........      $26,353,335      $26,104,448
                                                    ===========      ===========
</TABLE>


                 See accompanying notes to financial statements.
                                       F-3


<PAGE>
                               NL INDUSTRIES, INC.
                             RETIREMENT SAVINGS PLAN

STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS WITH FUND INFORMATION

                          Year ended December 31, 1998

<TABLE>
<CAPTION>
                                                                              Fund Information
                                                         -----------------------------------------------------------
                                                                                              AIM
                                                         MFS Emerging      Templeton      International    AIM Value
                                                         Growth Fund       World Fund      Equity Fund       Fund
                                                         ------------      ----------     -------------    ---------
<S>                                                      <C>             <C>             <C>             <C>
Additions:
  Investment income:
    Net appreciation (depreciation) in the fair value
     of investments .................................    $   354,126     $   (85,801)    $    46,443     $   420,196
    Dividend income:
      NL Industries, Inc. ...........................           --              --              --              --
      Halliburton Company ...........................           --              --              --              --
      Dresser Industries ............................           --              --              --              --
      Tremont Corporation ...........................           --              --              --              --
      Other .........................................         11,692         132,397           5,780          62,572
    Interest income .................................           --              --              --              --
                                                         -----------     -----------     -----------     -----------

    Total investment income .........................        365,818          46,596          52,223         482,768
                                                         -----------     -----------     -----------     -----------
  Contributions:
    Participants ....................................         65,968          29,445          40,487          78,531
    Employer ........................................         45,032          24,465          19,677          59,013

                                                         -----------     -----------     -----------     -----------
      Total contributions ...........................        111,000          53,910          60,164         137,544

                                                         -----------     -----------     -----------     -----------
    Total additions .................................        476,818         100,506         112,387         620,312

Deductions - distributions ..........................         46,915           8,701          29,944         129,760

Net interfund transfers .............................        (59,634)       (957,929)        (34,577)     (1,125,860)

                                                         -----------     -----------     -----------     -----------
Net increase (decrease) .............................        370,269        (866,124)         47,866        (635,308)

Assets transferred to another plan ..................       (923,408)       (278,015)       (183,021)       (727,621)

Net assets available for benefits:
  Beginning of year .................................      1,876,572       1,783,781         422,276       2,449,561

                                                         -----------     -----------     -----------     -----------
  End of year .......................................    $ 1,323,433     $   639,642     $   287,121     $ 1,086,632
                                                         ===========     ===========     ===========     ===========
<CAPTION>
<PAGE>

                                                                        Fund Information
                                                        --------------------------------------------
                                                                                          ML Global
                                                        MFS Government    ML Equity      Allocation
                                                        Securities Fund  Index Trust      Fund, Inc.
                                                        ---------------  -----------     -----------
<S>                                                      <C>             <C>             <C>
Additions:
  Investment income:
    Net appreciation (depreciation) in the fair value
     of investments .................................    $     7,294     $   333,231     $   (11,565)
    Dividend income:
      NL Industries, Inc. ...........................           --              --              --
      Halliburton Company ...........................           --              --              --
      Dresser Industries ............................           --              --              --
      Tremont Corporation ...........................           --              --              --
      Other .........................................         21,304            --            28,954
    Interest income .................................           --              --              --
                                                         -----------     -----------     -----------

    Total investment income .........................         28,598         333,231          17,389

                                                         -----------     -----------     -----------
  Contributions:
    Participants ....................................         13,359          38,208          22,453
    Employer ........................................         12,398          36,780          18,762

                                                         -----------     -----------     -----------
      Total contributions ...........................         25,757          74,988          41,215

                                                         -----------     -----------     -----------
    Total additions .................................         54,355         408,219          58,604

Deductions - distributions ..........................          3,206          46,079          21,963

Net interfund transfers .............................        (64,127)       (142,787)       (173,518)

                                                         -----------     -----------     -----------
Net increase (decrease) .............................        (12,978)        219,353        (136,877)

Assets transferred to another plan ..................       (138,924)     (1,291,724)       (225,360)

Net assets available for benefits:
  Beginning of year .................................        435,437       1,571,231         630,476

                                                         -----------     -----------     -----------
  End of year .......................................    $   283,535     $   498,860     $   268,239
                                                         ===========     ===========     ===========
</TABLE>
                                       F-4
<PAGE>



                               NL INDUSTRIES, INC.
                             RETIREMENT SAVINGS PLAN

           STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS
                       WITH FUND INFORMATION (CONTINUED)

                    Year ended December 31, 1998 (Continued)

<TABLE>
<CAPTION>

                                                                      Fund Information (Continued)
                                         ------------------------------------------------------------------------------------
                                            ML Federal       ML Capital         ML Basic     ML Retirement    Mercury Global
                                           Securities          Fund,             Value       Preservation        Holdings,
                                              Trust             Inc.             Fund            Trust             Inc.
                                           -----------       ----------         --------     --------------    --------------

<S>                                       <C>              <C>              <C>              <C>              <C>
Additions:
  Investment income:
    Net appreciation (depreciation) in
     the fair value of investments ...    $      1,923     $    188,576     $    316,966     $       --       $     45,144
    Dividend income:
      NL Industries, Inc. ............            --               --               --               --               --
      Halliburton Company ............            --               --               --               --               --
      Dresser Industries .............            --               --               --               --               --
      Tremont Corporation ............            --               --               --               --               --
      Other ..........................          29,733          176,522          229,209             --             41,011
    Interest income ..................            --               --               --          1,002,946             --
                                          ------------     ------------     ------------     ------------     ------------


    Total investment income ..........          31,656          365,098          546,175        1,002,946           86,155
                                          ------------     ------------     ------------     ------------     ------------

  Contributions:
    Participants .....................          25,955           87,075          133,404          100,027             --
    Employer .........................          29,422           71,739          136,427           99,794             --
                                          ------------     ------------     ------------     ------------     ------------

      Total contributions ............          55,377          158,814          269,831          199,821             --
                                          ------------     ------------     ------------     ------------     ------------

    Total additions ..................          87,033          523,912          816,006        1,202,767           86,155

Deductions - distributions ...........           7,325          343,832          234,611        3,836,816           46,539

Net interfund transfers ..............         (47,098)        (401,387)         341,380        4,321,992         (148,928)
                                          ------------     ------------     ------------     ------------     ------------

Net increase (decrease) ..............          32,610         (221,307)         922,775        1,687,943         (109,312)

Assets transferred to another plan ...        (167,043)      (2,295,582)      (2,519,905)      (8,251,803)        (173,185)

Net assets available for benefits:
  Beginning of year ..................         604,321        5,507,309        4,787,468       19,196,152          572,551
                                          ------------     ------------     ------------     ------------     ------------

  End of year ........................    $    469,888     $  2,990,420     $  3,190,338     $ 12,632,292     $    290,054
                                          ============     ============     ============     ============     ============


<PAGE>

<CAPTION>
                                            Fund Information (Continued)
                                            -----------------------------
                                                  Common Stock Funds
                                            -----------------------------
                                                             Halliburton/        Cash
                                                 NL             Tremont          Fund             Total
                                            ------------     ------------    ------------     ------------


<S>                                       <C>              <C>              <C>              <C>
  Investment income:
    Net appreciation (depreciation) in
     the fair value of investments ...    $    672,669     $   (146,054)    $       --       $  2,143,148
    Dividend income:
      NL Industries, Inc. ............          13,803             --               --             13,803
      Halliburton Company ............            --              1,239             --              1,239
      Dresser Industries .............            --              6,057             --              6,057
      Tremont Corporation ............            --                453             --                453
      Other ..........................            --               --               --            739,174
    Interest income ..................            --               --             (8,895)         994,051
                                          ------------     ------------     ------------     ------------

    Total investment income ..........         686,472         (138,305)          (8,895)       3,897,925
                                          ------------     ------------     ------------     ------------

  Contributions:
    Participants .....................          74,125             --            (44,594)         664,443
    Employer .........................          45,020             --              1,370          599,899
                                          ------------     ------------     ------------     ------------

      Total contributions ............         119,145             --            (43,224)       1,264,342
                                          ------------     ------------     ------------     ------------

    Total additions ..................         805,617         (138,305)         (52,119)       5,162,267

Deductions - distributions ...........          35,384            5,434           15,554        4,812,063

Net interfund transfers ..............      (1,373,683)        (133,844)            --               --
                                          ------------     ------------     ------------     ------------

Net increase (decrease) ..............        (603,450)        (277,583)         (67,673)         350,204

Assets transferred to another plan ...        (409,376)            --               --        (17,584,967)

Net assets available for benefits:
  Beginning of year ..................       3,041,977          641,313           67,673       43,588,098
                                          ------------     ------------     ------------     ------------

  End of year ........................    $  2,029,151     $    363,730     $       --       $ 26,353,335
                                          ============     ============     ============     ============
</TABLE>



                                       F-5


<PAGE>



                               NL INDUSTRIES, INC.
                             RETIREMENT SAVINGS PLAN

                STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE FOR
                   BENEFITS WITH FUND INFORMATION (CONTINUED)

                          Year ended December 31, 1999

<TABLE>
<CAPTION>
                                                               Fund Information
                                        ------------------------------------------------------------
                                                                             AIM
                                        MFS Emerging      Templeton     International     AIM Value
                                        Growth Fund      World Fund      Equity Fund         Fund
                                        ------------     ----------     -------------     ---------
<S>                                     <C>             <C>             <C>            <C>
Additions:
  Investment income:
  Net appreciation (depreciation) in
   the fair value of investments ...    $   518,333     $   118,136     $   142,437    $   288,492
    Dividend income:
      NL Industries, Inc. ..........           --              --              --             --
      Halliburton Company ..........           --              --              --             --
      Tremont Corporation ..........           --              --              --             --
      Other ........................          7,352          56,641          14,768        124,316
    Interest income ................           --              --              --             --
                                        -----------     -----------     -----------    -----------

    Total investment income ........        525,685         174,777         157,205        412,808
                                        -----------     -----------     -----------    -----------

  Contributions:
    Participants ...................         74,441          28,241          20,758         85,351
    Employer .......................         37,774          20,306          17,214         40,660
                                        -----------     -----------     -----------    -----------

      Total contributions ..........        112,215          48,547          37,972        126,011
                                        -----------     -----------     -----------    -----------

    Total additions ................        637,900         223,324         195,177        538,819

Deductions - distributions .........         81,362          50,707          23,543         98,892

Net interfund transfers ............       (267,567)         (3,145)         20,048        470,320
                                        -----------     -----------     -----------    -----------

Net increase (decrease) ............        288,971         169,472         191,682        910,247

Net assets available for benefits:
  Beginning of year ................      1,323,433         639,642         287,121      1,086,632
                                        -----------     -----------     -----------    -----------

  End of year ......................    $ 1,612,404     $   809,114     $   478,803    $ 1,996,879
                                        ===========     ===========     ===========    ===========
<PAGE>

<CAPTION>
                                                                       ML Global
                                       MFS Government   ML Equity      Allocation
                                       Securities Fund  Index Trust    Fund, Inc.
                                       ---------------  -----------    -----------
<S>                                     <C>             <C>            <C>
Additions:
  Investment income:
  Net appreciation (depreciation) in
   the fair value of investments ...    $   (24,919)    $   114,469    $    24,805
    Dividend income:
      NL Industries, Inc. ..........           --              --             --
      Halliburton Company ..........           --              --             --
      Tremont Corporation ..........           --              --             --
      Other ........................         16,991            --           40,600
    Interest income ................           --              --             --
                                        -----------     -----------    -----------

    Total investment income ........         (7,928)        114,469         65,405
                                        -----------     -----------    -----------

  Contributions:
    Participants ...................          8,304          60,162         15,788
    Employer .......................          3,455          33,690          5,181
                                        -----------     -----------    -----------

      Total contributions ..........         11,759          93,852         20,969
                                        -----------     -----------    -----------

    Total additions ................          3,831         208,321         86,374

Deductions - distributions .........         29,000          85,815         72,139

Net interfund transfers ............        (19,420)         79,097          9,574
                                        -----------     -----------    -----------

Net increase (decrease) ............        (44,589)        201,603         23,809

Net assets available for benefits:
  Beginning of year ................        283,535         498,860        268,239
                                        -----------     -----------    -----------

  End of year ......................    $   238,946     $   700,463    $   292,048
                                        ===========     ===========    ===========
</TABLE>




                                       F-6


<PAGE>



                               NL INDUSTRIES, INC.
                             RETIREMENT SAVINGS PLAN

           STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS
                       WITH FUND INFORMATION (CONTINUED)

                    Year ended December 31, 1999 (Continued)

<TABLE>
<CAPTION>
                                                                   Fund Information (Continued)
                                          --------------------------------------------------------------------------------
                                                                                                                Mercury
                                           ML Federal      ML Capital         ML Basic       ML Retirement       Global
                                           Securities        Fund,              Value        Preservation       Holdings,
                                             Trust            Inc.              Fund             Trust            Inc.
                                          ------------     ------------     ------------     ------------     ------------
<S>                                       <C>              <C>              <C>              <C>              <C>
Additions:
  Investment income:
    Net appreciation (depreciation) in
     the fair value of investments ...    $    (20,367)    $   (183,315)    $     12,462     $       --       $     31,467
    Dividend income:
      NL Industries, Inc. ............            --               --               --               --               --
      Halliburton Company ............            --               --               --               --               --
      Tremont Corporation ............            --               --               --               --               --
      Other ..........................          21,110          309,531          328,016             --             99,114
    Interest income ..................            --               --               --            699,089             --
                                          ------------     ------------     ------------     ------------     ------------


    Total investment income ..........             743          126,216          340,478          699,089          130,581
                                          ------------     ------------     ------------     ------------     ------------

  Contributions:
    Participants .....................          26,749           59,046          135,093           78,060             --
    Employer .........................          10,816           20,089           61,242           42,939             --
                                          ------------     ------------     ------------     ------------     ------------

      Total contributions ............          37,565           79,135          196,335          120,999             --
                                          ------------     ------------     ------------     ------------     ------------

    Total additions ..................          38,308          205,351          536,813          820,088          130,581

Deductions - distributions ...........         216,318          228,954          190,792        3,024,555           11,475

Net interfund transfers ..............         (57,983)        (264,869)        (388,612)         579,246           (3,777)
                                          ------------     ------------     ------------     ------------     ------------

Net increase (decrease) ..............        (235,993)        (288,472)         (42,591)      (1,625,221)         115,329

Net assets available for benefits:
  Beginning of year ..................         469,888        2,990,420        3,190,338       12,632,292          290,054
                                          ------------     ------------     ------------     ------------     ------------

  End of year ........................    $    233,895     $  2,701,948     $  3,147,747     $ 11,007,071     $    405,383
                                          ============     ============     ============     ============     ============
<PAGE>
<CAPTION>
                                          Fund Information (Continued)
                                          -----------------------------
                                                Common Stock Funds
                                          -----------------------------
                                                           Halliburton/         Cash
                                               NL             Tremont           Fund             Total
                                          ------------     ------------     ------------     ------------
<S>                                       <C>              <C>              <C>              <C>
Additions:
  Investment income:
    Net appreciation (depreciation) in
     the fair value of investments ...    $    132,645     $     75,437     $       --       $  1,230,082
    Dividend income:
      NL Industries, Inc. ............          20,054             --               --             20,054
      Halliburton Company ............            --              4,027             --              4,027
      Tremont Corporation ............            --                594             --                594
      Other ..........................            --               --               --          1,018,439
    Interest income ..................            --               --               --            699,089

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

    Total investment income ..........         152,699           80,058             --          2,972,285
                                          ------------     ------------     ------------     ------------

  Contributions:
    Participants .....................          50,052             --             35,374          677,419
    Employer .........................          14,092             --               --            307,458
                                          ------------     ------------     ------------     ------------

      Total contributions ............          64,144             --             35,374          984,877
                                          ------------     ------------     ------------     ------------

    Total additions ..................         216,843           80,058           35,374        3,957,162

Deductions - distributions ...........          90,570            2,980           (1,053)       4,206,049

Net interfund transfers ..............         (38,612)        (114,300)            --               --
                                          ------------     ------------     ------------     ------------

Net increase (decrease) ..............          87,661          (37,222)          36,427         (248,887)

Net assets available for benefits:
  Beginning of year ..................       2,029,151          363,730             --         26,353,335
                                          ------------     ------------     ------------     ------------

  End of year ........................    $  2,116,812     $    326,508     $     36,427     $ 26,104,448
                                          ============     ============     ============     ============
</TABLE>



                 See accompanying notes to financial statements.
                                       F-7


<PAGE>



                               NL INDUSTRIES, INC.
                             RETIREMENT SAVINGS PLAN

                          NOTES TO FINANCIAL STATEMENTS


Note 1 - Summary of significant accounting policies:

           The  financial  statements  of the  NL  Industries,  Inc.  Retirement
Savings Plan (the  "Plan")  have been  prepared in  accordance  with  accounting
principles  generally  accepted in the United States. The following is a summary
of the significant accounting policies followed by the Plan.

Investments

           Investments  are recorded at fair value based upon the quoted  market
price reported on the last trading day of the period for those securities listed
on a  national  securities  exchange.  Listed  securities  for which no sale was
reported on that date are valued at the mean  between the last  reported bid and
ask prices. Short-term investments are stated at fair value.

           Purchases  and sales of  investments  are  reflected  on a trade-date
basis.  Gains or losses on sales of securities  are based on average  cost.  The
Plan  presents in the  statements  of changes in net assets  available  for plan
benefits  the  net  appreciation   (depreciation)  in  the  fair  value  of  its
investments  which  consists of the realized  gains or losses and the unrealized
appreciation (depreciation) on those investments.

Contributions

           Contributions  from employees are recorded in the period the employer
makes payroll deductions from Plan participants. Employer contributions, if any,
are accrued at the end of each year and are received in the subsequent year.

Investment income

           Income from  investments  is recorded as earned on an accrual  basis.
Dividend income is recorded at the ex-dividend date.

Termination of Plan

           Although  it has not  expressed  any intent to do so, NL  Industries,
Inc. has the right under the Plan to discontinue  contributions and to terminate
the Plan at any time subject to penalties  set forth in the Employee  Retirement
Income Security Act of 1974 ("ERISA").  In the event of such a discontinuance or
termination  of the Plan,  the net assets of the Plan would be  allocated to the
Plan  participants as prescribed by the Plan document,  ERISA,  and the Internal
Revenue Code.

Management's Estimates

           The preparation of financial statements in conformity with accounting
principles  generally accepted in the United States requires  management to make
estimates  and  assumptions  that  affect  the  reported  amounts  of net assets
available for benefits at the date of the financial  statements,  the changes in
net  assets  available  for  benefits  during the  reporting  period  and,  when
applicable,  the disclosures of contingent assets and liabilities at the date of
the financial statements. Actual results could differ from those estimates.

Note 2 - Plan description:

           The Plan's principal objective is to provide eligible employees of NL
Industries, Inc. and its U.S. subsidiaries (the "Company") with a convenient way
to save on a regular and long-term  basis.  The majority of the  Company's  U.S.
employees are eligible to  voluntarily  participate in the Plan after six months
of  employment.  At  December  31,  1999,  there  were  74  active  participants
(participants  currently  employed by the Company)  and 504 total  participants.
Active  participants may make basic  contributions of between 0% and 8% of their
eligible  compensation.  Basic  contributions  may consist of a  combination  of

                                       F-8
<PAGE>


pre-tax and after- tax earnings.  Generally,  pre-tax contributions are excluded
from  the  employee's  taxable  income  until  they  are  distributed.  Eligible
employees  that have elected to make the maximum  basic  contribution  of 8% may
also make a supplemental pre-tax or after-tax  contribution of between 1% and 4%
of their eligible compensation.

           In  accordance  with the Tax  Reform  Act of 1986,  participants  are
limited in the amount of salary reduction  contributions  which they may make to
the Plan under  Section  402(g) of the  Internal  Revenue Code  ($10,000  annual
maximum for 1999). Highly compensated participants may be required to adjust the
amount  of their  contributions  in  order to  permit  the Plan to  satisfy  the
nondiscrimination  requirements  of Sections  401(k) and 401(m) of the  Internal
Revenue Code.

           Employer  contributions  include  funds  that (i) match a portion  of
participants'  contributions and (ii) represent an annual  contribution of 3% of
employees  eligible earnings.  The Company's level of matching  contributions is
determined annually and is based upon the attainment of certain operating income
target levels approved by the Management, Development and Compensation Committee
of the Board of  Directors of the Company  (the "MD&C  Committee").  The Company
match  applies only to  participants'  basic  contributions.  The level of match
approved by the MD&C Committee for 1998 and 1999 was 75% and 50%,  respectively.
Employees  who are  eligible  to  participate  in the  Plan  receive  an  annual
contribution to their investment  account of 3% of their eligible  compensation,
subject  to IRS  limitations  on  eligible  compensation,  which  for  1999  was
$160,000.  The Company makes this annual contribution for each eligible employee
regardless of whether the employee elects to otherwise  participate in the Plan.
Beginning in 2000,  the Company  intends to increase  the employer  contribution
from 3% to 4%.

           A  participant  with less than three years of service is 0% vested in
employer contributions,  50% vested following three years of service, 75% vested
following  four years of service and fully vested in all employer  contributions
following five years of service.  Employer  contributions  are fully vested upon
death, retirement, or disability, as provided in the Plan.

           Forfeitures  of  employer  contributions  may occur if a  participant
terminates  employment  prior to the full vesting  period or if a participant or
beneficiary,  to whom a distribution  is payable,  cannot be located within five
years of the date on which such  distribution  became payable.  Forfeitures were
$18,015 in 1998 and $20,067 in 1999. Amounts forfeited are used in the following
order: (i) to restore the accounts of reemployed  participants,  (ii) to restore
the accounts of participants or beneficiaries who apply for forfeited  benefits,
and  (iii) to reduce  employer  contributions.  The  balance  in the  forfeiture
account at December  31, 1999 was  $236,139.  Substantially  all of this balance
is expected to be used to reduce future employer contributions.

           The  Plan  was   amended   effective   January  1,  2000  to  provide
participants  with the  opportunity  to borrow  cash from their  vested  savings
balance.  Participants will be able to borrow from their fund accounts a minimum
of $1,000 up to a maximum that is generally equal to the lesser of $50,000 or 50
percent  of  their  account  balance,  whichever  is  less.  The  loans  will be
collateralized by the balance in the participant's  account and bear interest at
rates which are commensurate with local prevailing rates. Principal and interest
will be repaid ratably through monthly payroll deductions.

           The  specialty  chemical  business  of Rheox,  Inc.,  a wholly  owned
subsidiary  of the Company,  was sold to  Elementis  plc in January 1998 and $18
million of the Plan's assets were  distributed  to Elementis  America Inc. Rheox
Inc. Retirement Savings Plan, a retirement plan administered by Elementis plc.

           Merrill  Lynch  Trust  Company  ("Merrill  Lynch" or "ML")  serves as
trustee for the Plan.

           Employees may elect to have their own  contributions  invested in one
or more funds, whose investment objectives are as follows:


                                       F-9

<PAGE>
<TABLE>
<CAPTION>

                                                                                             Number of
                                                                                           participants at
                                                                                             December 31,
                                                                                           ---------------
                                                                                           1998       1999
                                                                                           ----       ----

<S>                                                                                        <C>        <C>
MFS  Emerging  Growth  Fund - Class A Shares -  managed  with the  objective  of            62         65
providing long-term growth of capital by investing primarily in common stocks of
companies  that are early in their life  cycles or are major  enterprises  whose
rates of earnings growth are expected to accelerate.

Templeton  World Fund - Class A Shares - managed  with the  objective of seeking            44         47
long-term  capital growth by investing in securities of companies or governments
located  throughout the world. The fund's portfolio is invested in securities of
both U.S. and foreign issuers.

AIM  International  Equity Fund - Class A Shares - managed with the objective of            37         40
seeking  long-term return of capital by investing in a diversified  portfolio of
international equity securities.

AIM  Value  Fund - Class A Shares -  managed  with the  objective  of  achieving            58         72
long-term growth of capital by investing primarily in equity securities of large
companies with strong earnings  prospects that are  undervalued  relative to the
equity market as a whole.

MFS Government  Securities Fund - Class A Shares - managed with the objective of            27         21
providing   current  income  and  preservation  of  principal  by  investing  in
Government   Securities  and  by  investing  in   obligations   that  are  fully
collateralized or otherwise fully secured by Government Securities.

Merrill Lynch Equity Index Trust - managed with the  objective of  approximating            46         55
the total return of the Standard & Poor's 500 Composite Stock Index.  This index
is  a  means  to  measure  the  performance  of  a  broad  base  of  large  U.S.
corporations.

Merrill Lynch Global  Allocation  Fund, Inc. - Class A Shares - managed with the            38         35
objective of seeking a high total investment return, consistent with the prudent
risk,  through a fully managed  investment  policy  utilizing  United States and
foreign equity,  debt and money market  securities the combination of which will
be varied from time to time both with respect to types of securities and markets
in response to changing market and economic trends.

Merrill  Lynch  Federal  Securities  Trust - Class A Shares -  managed  with the            72         40
objective  of  seeking  a  high  current  return  through  investments  in  U.S.
government and government agency securities.

Merrill Lynch  Capital Fund,  Inc. - Class A Shares - managed with the objective            98         94
of  seeking  the  highest  total  investment  return  through  a  fully  managed
investment   policy  utilizing   equity,   debt  (including  money  market)  and
convertible securities.

Merrill  Lynch  Basic  Value  Fund,  Inc.  - Class A Shares -  managed  with the            94         92
objective of seeking capital appreciation and, secondarily,  income by investing
in  securities,   primarily  equities,  that  fund  management  believes  to  be
undervalued.

Merrill  Lynch  Retirement  Preservation  Trust - managed with the  objective of           300        174
providing  preservation  of  capital,  liquidity  and  current  income at levels
typically  higher than those  provided by money market funds.  The trust invests
primarily in a broadly diversified  portfolio of Guaranteed Investment Contracts
and in high-quality money market securities.

NL Stock Fund - invested in NL common stock.                                               377        354

</TABLE>


                                       F-10

<PAGE>



           In addition to the funds listed above, the Halliburton/Tremont  Stock
Fund  holds   investments  in  Halliburton  for  44  participants   and  Tremont
Corporation common stock for 32 participants.  Investments in the Mercury Global
Holdings  Fund  (formerly  the Merrill  Lynch  Global  Holdings  Fund),  with 17
participants,   were  frozen  in  1996.  Contributions  or  transfers  into  the
Halliburton/Tremont  Stock  Fund and the  Mercury  Global  Holdings  Fund are no
longer allowed.

           Prior to the investment in securities of a type  consistent  with the
objectives of any fund,  cash may be  temporarily  invested in  securities  with
maturities of less than one year issued or guaranteed by the U.S.  government or
any agency or instrumentality thereof or deposited in a bank savings account.

           Interfund  transfers may be made daily, except that only one transfer
per  participant  per quarter may affect amounts in the NL Stock Fund.  Only one
transfer is permitted out of the Halliburton/Tremont  Stock Fund which must be a
transfer of the total value of the participant's account in that fund.

           Distributions  to employees may occur during  active  service or upon
termination and under prescribed circumstances. Distributions may be in the form
of lump sums, installments, annuities, or combinations thereof, or distributions
of employer securities.

           The Company bears the responsibility of all  administrative  expenses
of the Plan.

Note 3 - Related party transactions:

           The NL Stock Fund and the  Halliburton/Tremont  Stock Fund  invest in
the  common  stock of NL and  Tremont,  both of which  entities  are  considered
related  parties.  The activity of these securities for the years ended December
31, 1998 and 1999 was as follows:

<TABLE>
<CAPTION>

                                                    Sales and
                                                  distributions,    Realized
                                    Purchases        at cost       gain (loss)
                                   -----------    --------------   -----------

<S>                                <C>             <C>             <C>
Year ended December 31, 1998:
  NL common stock ...........      $  302,532      $1,155,944      $  758,178
  Tremont common stock ......             453           3,085          18,782

Year ended December 31, 1999:
  NL common stock ...........      $  158,787      $  289,856      $ (117,013)
  Tremont common stock ......             594             541             544

</TABLE>


Note 4 - Tax status:

           The Plan,  as amended,  is designed to  constitute a qualified  trust
under  Sections  401(a)  and 401(k) of the  Internal  Revenue  Code of 1986,  as
amended (the  "Code");  as such the Plan is exempt from federal  income tax, and
amounts  contributed by the Company will not be taxed to the  participant  until
the participant receives a distribution from the Plan.

           The Plan has  received a  favorable  determination  as of March 1998,
indicating it is a "Qualified  Plan" under the  requirements  of Sections 401(a)
and 401(k) of the Code and is qualified for favorable tax treatment. The Company
intends  to  file  an  application  with  the  Internal  Revenue  Service  for a
determination  of the qualified  status of the Plan under Section  401(a) of the
code for all amendments made to the Plan since the last determination letter.


                                      F-11

<PAGE>



Note 5 - Investments:

           The historical cost and fair value of each of the investments and the
employer contributions receivable balances at December 31, 1998 and 1999 were as
follows:
<TABLE>
<CAPTION>


                                                                                 December 31,
                                          -----------------------------------------------------------------------------------------
                                                             1998                                           1999
                                          --------------------------------------------   ------------------------------------------
                                                                           Employer                                     Employer
                                           Historical                    contributions   Historical                   contributions
Fund description                              cost         Fair value     receivable        cost         Fair value    receivable
----------------------------------------   ----------      ----------    -------------   ----------      ----------   -------------

<S>                                         <C>            <C>            <C>            <C>            <C>            <C>
NL Stock Fund ..........................    $ 1,915,419    $ 1,984,132    $    45,019    $ 1,784,350    $ 2,102,721    $    14,091
Halliburton/Tremont Stock Fund:
  Halliburton common stock .............        111,251        292,779           --           83,352        294,938           --
  Tremont common stock .................         18,061         70,951           --           18,113         31,570           --
                                            -----------    -----------    -----------    -----------    -----------    -----------

      Total common stock ...............      2,044,731      2,347,862         45,019      1,885,815      2,429,229         14,091
                                            -----------    -----------    -----------    -----------    -----------    -----------

MFS Emerging Growth Fund -
 Class A Shares ........................        970,670      1,278,402         45,031        839,743      1,574,630         37,774

Templeton World Fund -
 Class A Shares ........................        651,335        615,177         24,465        710,937        788,808         20,306

AIM International Equity Fund -
 Class A Shares ........................        238,380        267,444         19,677        295,501        461,589         17,214

AIM Value Fund - Class A Shares ........        856,310      1,027,619         59,013      1,530,196      1,956,219         40,660

MFS Government Securities Fund -
 Class A Shares ........................        259,186        271,136         12,399        243,810        235,490          3,456

Merrill Lynch Equity Index Trust .......        321,945        462,080         36,780        439,237        666,773         33,690

Merrill Lynch Global Allocation Fund,
 Inc. - Class A Shares .................        287,551        249,476         18,763        294,057        286,867          5,181

Merrill Lynch Federal Securities Trust -
 Class A Shares ........................        435,316        440,463         29,425        230,397        223,078         10,817

Merrill Lynch Capital Fund, Inc. -
 Class A Shares ........................      2,490,537      2,918,680         71,740      2,511,013      2,681,860         20,088

Merrill Lynch Basic Value Fund, Inc. -
 Class A Shares ........................      2,396,955      3,053,911        136,427      2,605,534      3,086,505         61,242

Merrill Lynch Retirement Preservation
 Trust .................................     12,532,499     12,532,499         99,793     10,964,132     10,964,132         42,939

Mercury Global Holdings, Inc. -
 Class I Shares ........................        274,766        290,054           --          360,422        405,383           --
                                            -----------    -----------    -----------    -----------    -----------    -----------

      Total other securities ...........     21,715,450     23,406,941        553,513     21,024,979     23,331,334        293,367
                                            -----------    -----------    -----------    -----------    -----------    -----------

                                            $23,760,181    $25,754,803    $   598,532    $22,910,794    $25,760,563    $   307,458
                                            ===========    ===========    ===========    ===========    ===========    ===========
</TABLE>

           Investments  whose  fair  value  exceeds  five  percent of net assets
available  for benefits  were the NL Stock Fund,  Merrill  Lynch  Capital  Fund,
Merrill Lynch Basic Value Fund, and Merrill Lynch Retirement  Preservation Trust
Fund at December 31, 1998 and 1999 and the MFS Emerging  Growth Fund and the AIM
Value Fund at December 31, 1999.


                                      F-12

<PAGE>



           Cash  at   December   31,   1999  of  $36,427   represents   rollover
contributions  from participants which have not yet been allocated to individual
funds.  At June 8, 2000, the market value of the shares of NL,  Halliburton  and
Tremont  stock held at December 31, 1999 was  $2,399,450,  $341,659 and $37,094,
respectively.

           The Plan's  assets are  invested  principally  in common stock of NL,
Halliburton and Tremont, and with investment funds managed by (i) Merrill Lynch,
ii) Massachusetts  Financial Services ("MFS"), iii) AIM Advisors,  Inc., and iv)
Templeton  Global  Advisors  Limited.  At December 31,  1999,  71% of the Plan's
investments were managed by Merrill Lynch.



                                      F-13

<PAGE>



                             SUPPLEMENTAL SCHEDULES


<PAGE>



                   NL INDUSTRIES, INC. RETIREMENT SAVINGS PLAN

         SCHEDULE OF ASSETS HELD FOR INVESTMENT PURPOSES AT END OF YEAR

                                December 31, 1999

                     Employer Identification No. 13-5267260

                                  Plan No. 003

<TABLE>
<CAPTION>
                                                                          Cost       Fair value
                                                                      -----------   -----------

<S>                                                                   <C>           <C>
   MFS Emerging Growth Fund - Class A shares ......................   $   839,743   $ 1,574,630

   Templeton World Fund - Class A shares ..........................       710,937       788,808

   AIM International Equity Fund - Class A shares .................       295,501       461,589

   AIM Value Fund - Class A shares ................................     1,530,196     1,956,219

   MFS Government Securities Fund - Class A shares ................       243,810       235,490

*  Merrill Lynch Equity Index Trust ...............................       439,237       666,773

*  Merrill Lynch Global Allocation Fund, Inc.- Class A shares .....       294,057       286,867

*  Merrill Lynch Federal Securities Trust - Class A shares ........       230,397       223,078

*  Merrill Lynch Capital Fund, Inc. - Class A shares ..............     2,511,013     2,681,860

*  Merrill Lynch Basic Value Fund, Inc. - Class A shares ..........     2,605,534     3,086,505

*  Merrill Lynch Retirement Preservation Trust ....................    10,964,132    10,964,132

*  Mercury Global Holdings, Inc. - Class I shares (formerly Merrill
     Lynch Global Holdings) .......................................       360,422       405,383

*  NL Stock Fund - common stock ...................................     1,784,350     2,102,721

   Halliburton/Tremont Stock Fund - common stock:
      Halliburton Company .........................................        83,352       294,938
   *  Tremont Corporation .........................................        18,113        31,570
                                                                      -----------   -----------

                                                                      $22,910,794   $25,760,563
                                                                      ===========   ===========
</TABLE>

Note:        Cost is determined  based on historical  cost.  Gains and losses on
             sales of investments are calculated based on average cost.

* Investment in a "Party-in-interest" entity, as defined by ERISA.

                                      F-14

<PAGE>



                               NL INDUSTRIES, INC.
                             RETIREMENT SAVINGS PLAN
                       SCHEDULE OF REPORTABLE TRANSACTIONS
                          Year ended December 31, 1999
                     Employer Identification No. 13-5267260
                                  Plan No. 003

<TABLE>
<CAPTION>


                                                                                                       Fair value
                                                                                                       of asset on
                                                  Number of    Purchase      Selling        Cost of    transaction
Description of Asset                            Transactions     price        price          asset        date         Net gain
--------------------                            ------------  ----------    --------      ----------   -----------   -----------

<S>                                                   <C>     <C>           <C>           <C>           <C>           <C>
Merrill Lynch Retirement Preservation Trust:
  Purchases ................................          97      $2,030,303    $     --      $2,030,303    $2,030,303    $     --
  Sales ....................................          58            --       3,598,571     3,598,571     3,598,571          --

Merrill Lynch Basic Value Fund Class A:
  Purchases ................................          44         828,671          --         828,671       828,671          --
  Sales ....................................          33            --         789,896       601,449       789,896       188,447

</TABLE>


                                      F-15

<PAGE>
                                                                       EXHIBIT I




                       CONSENT OF INDEPENDENT ACCOUNTANTS



We hereby consent to the incorporation by reference in the:

(i)            Registration  Statement  No.  33-29287  on Form  S-8 and  related
               Prospectus  with  respect  to  the  1989  Long  Term  Performance
               Incentive Plan of NL Industries, Inc.; and

(ii)           Registration  Statement  No.  33-25913  on Form  S-8 and  related
               Prospectus  with respect to the NL  Industries,  Inc.  Retirement
               Savings Plan; and

(iii)          Registration  Statement  No.  33-48145  on Form  S-8 and  related
               Prospectus   with  respect  to  the  NL  Industries,   Inc.  1992
               Non-Employee Directors Stock Option Plan; and

(iv)           Registration  Statement  No.  333-65817  on Form S-8 and  related
               Prospectus with respect to the NL Industries, Inc. 1998 Long-Term
               Incentive Plan.


of our report dated June 8, 2000 relating to the financial  statements of the NL
Industries, Inc. Retirement Savings Plan which appears in this Form 11-K.







                                             PricewaterhouseCoopers LLP





Houston, Texas
June 27, 2000