Additional Information

The reporting person may also be deemed to own directly or
indirectly and beneficially the following shares of common
stock, par value $1.00 per share (the "Common Stock"), of
the issuer (see below for a description of how the
reporting person is related to the following direct
holders):

(1)  4,109,159 shares directly held by the Contran
Corporation ("Contran");

(2)  326,364 shares directly held by Valhi, Inc. ("Valhi");
and

(3)  326,050 shares directly held by NL Industries, Inc.
("NL").

Contran also directly holds 54,956 shares of the issuer's
Series A 10% Cumulative Convertible Pay-In-Kind Preferred
Stock, stated value $1,000 and no par value per share (the
"Series A Preferred Stock"), the terms of which are set
forth in, and incorporated herein by reference from, the
Amended and Restated Certificate of Designations, Rights
and Preferences of the Series A 10% Cumulative Convertible
Pay-In-Kind Preferred Stock filed as Exhibit 3.2 to the
issuer's Annual Report on Form 10-K for the fiscal year
ended December 31, 2002 with the Securities and Exchange
Commission.

On or after March 15, 2003, Contran has the right to
convert all of its shares of Series A Preferred Stock into
an aggregate of 13,739,000 shares of Common Stock.
Currently, however, the issuer's Restated Certificate of
Incorporation only allows for the issuance of 12,000,000
shares of Common Stock, of which 10,068,450 are currently
issued and outstanding. The reporting person understands
that the issuer will present a proposal at its next annual
meeting of stockholders to amend its Restated Certificate
of Incorporation to allow for the issuance of at least such
number of shares of Common Stock that the issuer is
obligated to issue upon full conversion of the outstanding
shares of Series A Preferred Stock.  Assuming the issuer's
Restated Certificate of Incorporation is so amended on or
after March 15, 2003, Keystone's outstanding equity
securities remain the same and Harold C. Simmons' current
beneficial ownership of such securities otherwise remains
the same, as a result of the conversion rights of Contran's
shares of Series A Preferred Stock, Mr. Simmons may be
deemed, at the time of such amendment, to be the beneficial
owner of 18,729,618 shares of the 23,807,450 shares of
Common Stock outstanding (adjusting the outstanding shares
of Common Stock assuming only Contran exercises its conversion
rights and does so in full), or 78.7% of such outstanding shares
of Common Stock.

Contran, Valhi, NL, the Harold Simmons Foundation, Inc.
(the "Foundation") and The Combined Master Retirement Trust
(the "CMRT") are the direct holders of approximately 40.8%,
3.2%, 3.2%, 1.9% and 0.3%, respectively, of the outstanding
shares of Common Stock.

Valhi and Tremont LLC are the direct holders of
approximately 63.2% and 21.4%, respectively, of the
outstanding common stock of NL.  Valhi is the direct holder
of 100% of the membership interests of Tremont LLC.  Valhi
Group, Inc. ("VGI"), National City Lines, Inc.
("National"), Contran, the Foundation, the Contran Deferred
Compensation Trust No. 2 (the "CDCT No. 2") and the CMRT
are the direct holders of approximately 77.6%, 9.1%, 2.9%,
1.3%, 0.4% and 0.1%, respectively, of the outstanding
common stock of Valhi. National City Lines, Inc.
("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.  As
sole trustee of each of the Trusts, Mr. Simmons has the
power to vote and direct the disposition of the shares of
Contran stock held by each of the Trusts.  Mr. Simmons,
however, disclaims beneficial ownership of any shares of
Contran stock that the Trusts hold.

The CMRT directly holds approximately 0.3% of the
outstanding shares of Common Sock and 0.1% of the
outstanding shares of Valhi common stock.  Valhi
established the CMRT as a trust to permit the collective
investment by master trusts that maintain the assets of
certain employee benefit plans Valhi and related companies
adopt.  Mr. Simmons is the sole trustee of the CMRT and a
member 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.

The Foundation directly holds approximately 1.9% of the
outstanding shares of Common Sock and 1.3% 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 and may be deemed to control the
Foundation.

The CDCT No. 2 directly holds approximately 0.4% of the
outstanding 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 0.3% of the outstanding
shares of Common Stock and 0.1% of the outstanding shares of
Valhi common stock.  Valhi established the CMRT as a trust to
permit the collective investment by master trusts that maintain
the assets of certain employee benefit plans Valhi and related
companies adopt.  Mr. Simmons is the sole trustee of the CMRT
and a member 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.

The reporting person understands that Valmont Insurance
Company ("Valmont"), NL and a subsidiary of NL directly own
1,000,000, 3,522,967 and 1,186,200 shares of Valhi common
stock, respectively, as of the date of this statement.
Valhi is the direct holder of 100% of the outstanding
common stock of Valmont.  As a result of Valhi's direct and
indirect ownership of Valmont, NL and its subsidiary, the
reporting person further understands that, pursuant to
Delaware law, Valhi treats its shares of common stock that
Valmont, NL and NL's subsidiary own as treasury stock for
voting purposes. For the purposes of this statement, such
shares of Valhi common stock that Valmont, NL and its
subsidiary hold directly are not deemed outstanding.

Mr. Harold C. Simmons is chairman of the board of Tremont
LLC, NL, Valhi, VGI, National, NOA, Dixie Holding, Dixie
Rice, Southwest and Contran.

By virtue of the holding of the offices, the stock
ownership and his service as trustee, all as described
above, (a) Mr. Simmons may be deemed to control the
entities described above and (b) Mr. Simmons and certain of
such entities may be deemed to possess indirect beneficial
ownership of the shares of Common Stock directly held by
certain of such other entities.  However, Mr. Simmons
disclaims beneficial ownership of the shares of Common
Stock beneficially owned, directly or indirectly, by any of
such entities.

Harold C. Simmons' spouse is the direct owner of 10,645
shares of Common Stock and 69,475 shares of NL common
stock.  Mr. Simmons may be deemed to share indirect
beneficial ownership of such shares.  Mr. Simmons disclaims
all such beneficial ownership.