SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* CONTRAN CORP (Last) (First) (Middle) 5430 LBJ FRWY SUITE 1700 (Street) DALLAS TX 75240 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol KRONOS WORLDWIDE INC [ KRO ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 04/06/2006
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock $0.01 par value	04/06/2006		J(1)		1,800	A	$30	28,899,821	I	by Valhi(2)
Common Stock $0.01 par value	04/07/2006		J(1)		5,000	A	$30	28,904,821	I	by Valhi(2)
Common Stock $0.01 par value	04/10/2006		J(1)		15,000	A	$29.75	28,919,821	I	by Valhi(2)
Common Stock $0.01 par value								17,516,132	I	by Valhi(3)
Common Stock $0.01 par value								5,203	I	by TFMC(4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* CONTRAN CORP (Last) (First) (Middle) 5430 LBJ FRWY SUITE 1700 (Street) DALLAS TX 75240 (City) (State) (Zip)

1. Name and Address of Reporting Person* VALHI INC /DE/ (Last) (First) (Middle) THREE LINCOLN CENTER 5430 LBJ FREEWAY SUITE 1700 (Street) DALLAS TX 75240 (City) (State) (Zip)

1. Name and Address of Reporting Person* DIXIE RICE AGRICULTURE CORP INC (Last) (First) (Middle) 600 PASQUIERE ST (Street) GUEYDAN LA 70542 (City) (State) (Zip)

1. Name and Address of Reporting Person* SOUTHWEST LOUISIANA LAND CO INC (Last) (First) (Middle) 402 CANAL ST (Street) HOUMA LA 70360 (City) (State) (Zip)

1. Name and Address of Reporting Person* TITANIUM METALS CORP (Last) (First) (Middle) TITANIUM METALS CORP 1999 BROADWAY SUITE 4300 (Street) DENVER CO 80202 (City) (State) (Zip)

1. Name and Address of Reporting Person* VALHI GROUP INC (Last) (First) (Middle) 5430 LBJ FREEWAY SUITE 1700 (Street) DALLAS TX 75240 (City) (State) (Zip)

1. Name and Address of Reporting Person* NL INDUSTRIES INC (Last) (First) (Middle) 5430 LBJ FREEWAY SUITE 1700 (Street) DALLAS TX 75240-2697 (City) (State) (Zip)

1. Name and Address of Reporting Person* TIMET FINANCE MANAGEMENT CO (Last) (First) (Middle) 913 N MARKET ST SUITE 217 (Street) WILMINGTON DE 19801 (City) (State) (Zip)

1. Name and Address of Reporting Person* VALHI HOLDING CO (Last) (First) (Middle) 5430 LBJ FREEWAY SUITE 1700 (Street) DALLAS TX 75240 (City) (State) (Zip)

1. Name and Address of Reporting Person* SIMMONS HAROLD C (Last) (First) (Middle) THREE LINCOLN CENTRE 5430 LBJ FREEWAY STE 1700 (Street) DALLAS TX 75240-2697 (City) (State) (Zip)

Explanation of Responses:

1. Open market purchase by Valhi, Inc. See the Additional Information filed as Exhibit 99 to this statement for a description of the relationships among the persons joining in this filing.

2. Open market purchase by Valhi, Inc. See the Additional Information filed as Exhibit 99 to this statement for a description of the relationships among the persons joining in this filing.

3. Directly held by NL Industries, Inc. See the Additional Information filed as Exhibit 99 to this statement for a description of the relationships among the persons joining in this filing.

4. Directly held by TIMET Finance Management Company. See the Additional Information filed as Exhibit 99 to this statement for a description of the relationships among the persons joining in this filing.

Remarks:

Mr. Harold C. Simmons and his spouse directly hold 4,755 and 36,356 shares, respectively, of the common stock of the issuer. Mr. Simmons disclaims beneficial ownership of the shares of the issuer's common stock that his spouse owns. This form is also filed on behalf of Dixie Holding Company, 5430 LBJ Freeway, Suite 1700, Dallas, TX 75240 By: /s/ A. Andrew R. Louis, Secretary (executed 04/10/2006), National City Lines, Inc., 5430 LBJ Freeway, Suite 1700, Dallas, TX 75240 By: /s/ A. Andrew R. Louis, Secretary (executed 04/10/2006) NOA, Inc., 5430 LBJ Freeway, Suite 1700, Dallas, TX 75240 By: /s/ A. Andrew R. Louis, Secretary (executed 04/10/2006) and Tremont LLC, 5430 LBJ Freeway, Suite 1700, Dallas, TX 75240 By: /s/ A. Andrew R. Louis, Secretary (executed 04/10/2006). See the Additional Information filed as Exhibit 99 to this statement for a description of the relationships among the persons joining in this filing. Exhibit Index Exhibit 99 - Additional Information

	A. Andrew R. Louis, Secretary, for Contran Corporation	04/10/2006
	A. Andrew R. Louis, Secretary, for Valhi, Inc.	04/10/2006
	A. Andrew R. Louis, Secretary, for Dixie Rice Agricultural Corporation, Inc.	04/10/2006
	A. Andrew R. Louis, Secretary, for Southwest Louisiana Land Company, Inc.	04/10/2006
	A. Andrew R. Louis, Assistant Secretary, for Titanium Metals Corporation	04/10/2006
	A. Andrew R. Louis, Secretary, for Valhi Group, Inc.	04/10/2006
	A. Andrew R. Louis, Assistant Secretary, for NL Industries, Inc.	04/10/2006
	Gregory M. Swalwell, Vice President, for TIMET Finance Management Company	04/10/2006
	A. Andrew R. Louis, Secretary, for Valhi Holding Company	04/10/2006
	A. Andrew R. Louis, Attorney-in-fact, for Harold C. Simmons	04/10/2006
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
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Exhibit 99 Additional Information

     Valhi,  Inc.  ("Valhi") and NL Industries,  Inc.  ("NL") are the holders of
59.1% and 35.8%,  respectively,  of the outstanding  shares of common stock, par
value $0.01 per share ("Common Stock"), of the issuer.

     Valhi and TIMET Finance  Management Company ("TFMC") are the direct holders
of approximately 83.1% and 0.5%,  respectively,  of the outstanding common stock
of NL. Valhi Holding Company ("VHC"),  the Harold Simmons Foundation,  Inc. (the
"Foundation"),  the Contran Deferred  Compensation Trust No. 2 (the "CDCT No.2")
and The Combined Master  Retirement Trust (the "CMRT") are the direct holders of
91.6%,  0.9%, 0.4% and 0.1%,  respectively,  of the common stock of Valhi. Valhi
Group,  Inc.  ("VGI"),  National  City  Lines,  Inc.  ("National"),  and Contran
Corporation ("Contran") are the direct holders of approximately 87.4%, 10.3% and
2.3%, respectively,  of the outstanding common stock of VHC. National, NOA, Inc.
("NOA") and Dixie Holding  Company  ("Dixie  Holding") are the direct holders of
approximately  73.3%, 11.4% and 15.3%,  respectively,  of the outstanding common
stock of VGI. Contran and NOA are the direct holders of approximately  85.7% and
14.3%,  respectively,  of the outstanding common stock of National.  Contran and
Southwest Louisiana Land Company,  Inc.  ("Southwest") are the direct holders of
approximately 49.9% and 50.1%, respectively,  of the outstanding common stock of
NOA.  Dixie Rice  Agricultural  Corporation,  Inc.  ("Dixie Rice") is the direct
holder of 100% of the outstanding common stock of Dixie Holding.  Contran is the
holder of 100% of the outstanding  common stock of Dixie Rice and  approximately
88.9% of the outstanding common stock of Southwest.

     Substantially all of Contran's  outstanding  voting stock is held by trusts
established for the benefit of certain  children and  grandchildren of Harold C.
Simmons (the "Trusts"),  of which Mr. Simmons is the sole trustee, or is held by
Mr. Simmons or persons or entities  related to Mr.  Simmons.  As sole trustee of
the Trusts,  Mr. Simmons has the power to vote and direct the disposition of the
shares of Contran stock held by the Trusts.  Mr.  Simmons  disclaims  beneficial
ownership of all Contran shares that the Trusts hold.

     Harold C. Simmons is the chairman of the board and chief executive  officer
of each of the  issuer  and NL and the  chairman  of the board of each of Valhi,
VHC, VGI, National, NOA, Dixie Holding, Dixie Rice, Southwest and Contran.

     The Foundation  directly holds approximately 0.9% of the outstanding shares
of Valhi common stock. The Foundation is a tax-exempt  foundation  organized for
charitable  purposes.  Harold C.  Simmons  is the  chairman  of the board of the
Foundation.

     The CDCT No. 2 directly holds  approximately 0.4% of the outstanding shares
of Valhi common stock. U.S. Bank National  Association  serves as the trustee of
the CDCT No. 2.  Contran  established  the CDCT No. 2 as an  irrevocable  "rabbi
trust" to assist Contran in meeting certain  deferred  compensation  obligations
that it owes to Harold C. Simmons.  If the CDCT No. 2 assets are insufficient to
satisfy  such  obligations,  Contran is obligated to satisfy the balance of such
obligations  as they come due.  Pursuant to the terms of the CDCT No. 2, Contran
(i) retains the power to vote the shares of Valhi common stock held  directly by
the CDCT No. 2, (ii) retains dispositive power over such shares and (iii) may be
deemed the indirect beneficial owner of such shares.

     The CMRT directly holds  approximately  0.1% of the  outstanding  shares of
Valhi common stock.  Contran  sponsors the CMRT,  which  permits the  collective
investment by master trusts that maintain the assets of certain employee benefit
plans Contran and related companies adopt. Harold C. Simmons is the sole trustee
of the  CMRT  and a member  of the  trust  investment  committee  for the  CMRT.
Contran's  board of  directors  selects  the  trustee  and  members of the trust
investment  committee for the CMRT.  Mr. Simmons is a participant in one or more
of the employee benefit plans that invest through the CMRT.

     By virtue of the  holding  of the  offices,  the  stock  ownership  and his
services as trustee, all as described above, (a) Harold C. Simmons may be deemed
to control such entities and (b) Mr. Simmons and certain of such entities may be
deemed to possess  indirect  beneficial  ownership  of shares  directly  held by
certain of such other entities.  However,  Mr. Simmons disclaims such beneficial
ownership of the shares beneficially owned directly or indirectly by any of such
entities,  except to the extent of his vested  beneficial  interest,  if any, in
shares held by the CMRT and his interest as a beneficiary of the CDCT No. 2. Mr.
Harold Simmons disclaims beneficial ownership of all shares of Common Stock that
Valhi, NL or TFMC directly holds.

     TFMC owns  5,203  shares  of  Common  Stock.  Titanium  Metals  Corporation
("TIMET")  owns  100% of the  outstanding  common  stock  of TFMC.  Tremont  LLC
("Tremont"),  Harold C. Simmons'  spouse,  the CMRT, Valhi and Harold C. Simmons
are  the  holders  of  approximately   33.4%,   12.6%,  10.2%,  3.8%  and  2.6%,
respectively,  of the  outstanding  common  stock of TIMET.  Valhi is the direct
holder of 100% of the  membership  interests  of Tremont.  The  ownership of Ms.
Simmons  includes  10,666,666  shares of TIMET's  common  stock that she has the
right to acquire upon conversion of 1,600,000  shares of TIMET's 6 3/4% Series A
Convertible Preferred Stock, par value $0.01 per share (the "Series A Preferrred
Stock"), that she holds directly.  The ownership of Valhi includes 98,000 shares
of TIMET's  common stock that Valhi has the right to acquire upon  conversion of
14,700  shares of Series A  Preferred  Stock  that  Valhi  directly  holds.  The
percentage  ownership  of TIMET's  common  stock held by Ms.  Simmons  and Valhi
assumes the full conversion of only the shares of Series A Preferred Stock owned
by her or Valhi,  respectively.  Harold C.  Simmons is  chairman of the board of
TIMET and Tremont.

     Harold C.  Simmons'  spouse is the direct owner of 36,356  shares of Common
Stock,  119,475 shares of NL common stock,  43,400 shares of Valhi common stock,
228,000 shares of TIMET common stock and 1,600,000  shares of Series A Preferred
Stock,  which are convertible into 10,666,666  shares of TIMET common stock. Mr.
Simmons may be deemed to share indirect beneficial ownership of such shares. Mr.
Simmons disclaims all such beneficial ownership.

     Harold C.  Simmons  directly  holds 4,755 shares of Common  Stock,  257,000
shares  of NL  common  stock  (including  stock  options  exercisable  for 4,000
shares), 3,383 shares of Valhi common stock and 1,933,700 shares of TIMET common
stock.

     A trust,  of which  Harold C.  Simmons and his spouse are  trustees and the
beneficiaries  are the  grandchildren  of his  spouse,  is the direct  holder of
36,500 shares of Valhi common stock.  Mr. Simmons,  as co-trustee of this trust,
has the power to vote and direct the  disposition  of the shares of Valhi common
stock the trust holds. Mr. Simmons disclaims  beneficial ownership of any shares
of Valhi common stock that this trust holds.

     NL and a subsidiary of NL directly own  3,522,967  and 1,186,200  shares of
Valhi common stock,  respectively.  Pursuant to Delaware  law,  Valhi treats the
shares of Valhi  common stock that NL and the  subsidiary  of NL own as treasury
stock for voting  purposes.  For the  purposes  of the  percentage  calculations
herein, such shares are not deemed outstanding.