Exhibit 99.1

      The following is a description of the relationships among the
Reporting Persons and certain related entities or persons that may
be deemed to beneficially own shares of the common stock, par value
$0.125 per share (the "NL Shares"), of the issuer, NL Industries,
Inc. ("NL").

	A majority of the outstanding voting stock of Contran
Corporation ("Contran") is held directly by Lisa K. Simmons and
various family trusts established for the benefit of Ms. Simmons,
Thomas C. Connelly (the husband of Ms. Simmons' late sister) and
their children and for which Ms. Simmons or Mr. Connelly, as
applicable, serve as trustee (collectively, the "Other Trusts").
With respect to the Other Trusts for which Mr. Connelly serves
as trustee, pursuant to the terms of a stockholders agreement
(the "Contran Stockholders Agreement") he is required to vote
the shares of Contran voting stock held in such trusts in the
same manner as Ms. Simmons. Such voting rights of Ms. Simmons
last through April 22, 2030 and are personal to Ms. Simmons.

	The remainder of Contran's outstanding voting stock is
held by the Harold C. Simmons Family Trust No 2 (the "Family
Trust"), which was established for the benefit of Ms. Simmons
and her late sister and their children and for which for which
Tolleson Private Bank serves as trustee (the "Trustee").

      Ms. Simmons serves as chair of the Contran board of directors
(the "Contran Board"), and one other member of Contran management
also serves on the Contran Board. The Trustee of the Family Trust
has the power to vote the shares of Contran stock held by the Family
Trust and to direct the disposition of such shares subject to certain
right-of-first-refusal limitations and restrictions as set forth in
the Contran Stockholders Agreement.  Ms. Simmons has the power to
vote the shares of Contran stock she holds directly or indirectly
(for the shares of Contran stock held by the Other Trusts for which
she serves as trustee), and by virtue of the Contran Stockholders
Agreement has the power to vote the shares of Contran stock held by
the Other Trusts for which she does not serve as trustee.  Ms. Simmons
has the power to direct the disposition of the shares of Contran stock
she holds directly or indirectly (for the shares of Contran stock held
by the Other Trusts for which she serves as trustee) subject to certain
right-of-first-refusal limitations and restrictions as set forth in the
Contran Stockholders Agreement.

      Contran is the holder of the sole membership interest of Dixie
Rice Agricultural L.L.C. ("Dixie Rice") and may be deemed to control
Dixie Rice.

      Ms. Simmons and the Family Trust directly hold, or are related
to the following persons or entities that directly hold, the following
percentages of the outstanding NL shares:

Valhi, Inc. ("Valhi")...........................................82.8%
Kronos Worldwide ("Kronos Worldwide")....................Less than 1%

Together, Valhi and Kronos Worldwide may be deemed to control NL.

      Ms. Simmons and the Family Trust directly hold, or are related
to the following persons or entities that directly hold, the following
percentages of the outstanding shares of Kronos Worldwide common stock:

Valhi...........................................................50.2%
NLKW Holding LLC ("NLKW").......................................30.5%
Contran..................................................Less than 1%

Together, Valhi, NL (and its wholly owned subsidiary NLKW) and Contran
may be deemed to control Kronos Worldwide.

      Ms. Simmons and the Family Trust directly hold, or are related
to the following persons or entities that directly hold, the following
percentages of the outstanding shares of Valhi common stock:

Dixie Rice......................................................91.5%

Dixie Rice may be deemed to control Valhi.

        NL (including a wholly owned subsidiary of NL) and Kronos
Worldwide own 14,372,970 shares and 1,724,916 shares, respectively,
of Valhi common stock. As already stated, Valhi is the direct holder
of approximately 82.8% of the outstanding shares of common stock of
NL and 50.2% of the outstanding shares of Kronos Worldwide common
stock.  As a result of Valhi's direct and indirect ownership of NL
and Kronos Worldwide and pursuant to Delaware law and Section
13(d)(4) of the Exchange Act, Valhi treats the shares of Valhi
common stock that NL and Kronos Worldwide own as treasury stock
for voting purposes. For the purposes of this statement, such
shares of Valhi common stock that NL and Kronos Worldwide hold
are not deemed outstanding.

      By virtue of the stock ownership of each of Kronos Worldwide,
NL, Valhi, Dixie Rice and Contran, Ms. Simmons being a beneficiary
of the Family Trust, the direct holdings of Contran voting stock
by Ms. Simmons, the voting rights conferred to Ms. Simmons by the
Contran Stockholders Agreement with respect to the Connelly Direct
Shares and the Connelly Indirect Shares, the position of chair of
the Contran Board by Ms. Simmons, and the Family Trust's ownership
of Contran voting stock, in each case as described above,
(a) Ms. Simmons and the Family Trust (and the Trustee, in its
capacity as trustee of the Family Trust) may be deemed to control
Contran, Dixie Rice, Valhi, NL and Kronos Worldwide and
(b) Ms. Simmons, the Family Trust (and the Trustee, in its capacity
as trustee of the Family Trust), Contran, Dixie Rice, Valhi, NL
and Kronos Worldwide may be deemed to possess indirect beneficial
ownership of, and a pecuniary interest in, shares of common stock
directly held by such entities, including any NL Shares.  However,
Ms. Simmons and the Family Trust (and the Trustee) each disclaims
beneficial ownership of, and such pecuniary interest in, such shares
beneficially owned, directly or indirectly, by any of such entities,
except to the extent of their direct beneficial ownership, if any,
in shares of such entities.