Document:

<PAGE>

                                                                    EXHIBIT 4(c)

                     SECOND AMENDMENT TO RIGHTS AGREEMENT

     This Agreement ( the "Amendment"), dated effective October 1, 2001, is
entered into by and among ChemFirst Inc., a Mississippi corporation (the
"Company"), The Bank of New York ("BONY") and American Stock Transfer & Trust
Company ("AST").

     WHEREAS, the Company and KeyCorp Shareholder Services, Inc. ("KeyCorp")
entered into a Rights Agreement dated as of October 30, 1996 whereby KeyCorp was
appointed Rights Agent under the Rights Agreement; and

     WHEREAS, effective May 1, 1997, the Company and BONY entered into the First
Amendment to Rights Agreement, whereby the KeyCorp Shareholder Services, Inc.,
was removed as Rights Agent and BONY was appointed the Rights Agent under the
Rights Agreement; and

     WHEREAS, the Company wishes to appoint AST as Rights Agent under the Rights
Agreement; and

     WHEREAS, Section 27 of the Rights Agreement provides, among other things,
that prior to the Distribution Date (as such term is defined in the Agreement),
the Company may, and the Rights Agent shall, if the Company so directs,
supplement or amend any provision of the Agreement without the approval of any
holders of certificates representing shares of Common Stock.

     NOW, THEREFORE, the Company, BONY and AST agree as follows:

1.   BONY is removed as Rights Agent and AST is appointed as successor Rights
     Agent effective October 1, 2001.

2.   The cover page of the Rights Agreement is hereby amended by striking the
     words "The Bank of New York" and inserting the words with "American Stock
     Transfer & Trust Company" in their place.

3.   The first page of the Rights Agreement is hereby amended by modifying the
     first paragraph such that said paragraph reads in its entirety as follows:

       RIGHTS AGREEMENT, dated as of October 30, 1996 (the "Agreement"), between
       ChemFirst Inc., a Mississippi corporation (the "Company"), and American
       Stock Transfer & Trust Company, a New York state banking corporation (the
       "Rights Agent"), successor to The Bank of New York, a New York trust
       company, successor to KeyCorp Shareholder Services, Inc., an Ohio
       corporation.

4.   The last paragraph of Section 3(c) of the Rights Agreement is hereby
     amended by striking the first two sentences, and inserting the following
     three sentences in their place:

       Any certificates representing shares of Common Stock bearing the
       foregoing legend shall be deemed to refer to American Stock Transfer &
       Trust Company as the Rights Agent. On and after October 1, 2001,
       certificates representing shares of Common Stock required to bear the
       foregoing legend may, in the alternative, bear the foregoing legend as
       modified by replacing "KeyCorp Shareholder Services, Inc." with "American
       Stock Transfer & Trust Company."
<PAGE>

6.   The fifth sentence of Section 21 of the Rights Agreement is hereby amended
     by striking the amount of "$100,000,000" and inserting the amount of
     "$10,000,000" in its place.

7.   Section 26 of the Rights Agreement is hereby amended by striking the
     following subparagraph:

       The Bank of New York
       101 Barclay St., Floor 12W
       New York NY 10286
       Attn: Stock Transfer Administration

     and inserting the following subparagraph in its place:

       American Stock Transfer & Trust Company
       59 Maiden Lane
       Plaza Level
       New York, NY 10038

8.   The first paragraph under the heading "CHEMFIRST INC." on Exhibit A to the
     Rights Agreement is hereby amended by striking the following language in
     the first sentence of said paragraph:

       The Bank of New York (the "Rights Agent"), successor to KeyCorp
       Shareholder Services, Inc., an Ohio corporation,

     and inserting the following language in its place:

       American Stock Transfer & Trust Company, a New York state banking
       corporation (the "Rights Agent"), successor to The Bank of New York, a
       New York trust company, successor to KeyCorp Shareholder Services, Inc.,
       an Ohio corporation,

     IN WITNESS WHEREOF, the parties have caused this Amendment to be duly
executed and their respective corporate seals to be hereunto affixed and
attested, all as of the day and year first above written.

ATTEST:                            CHEMFIRST INC.

By: /s/ James L. McArthur          By: /s/ R. M. Summerford
Name: James L. McArthur            Name: R. M. Summerford
Title: Secretary                   Title: President and COO

ATTEST:                            THE BANK OF NEW YORK

By: /s/ Jeffrey Grosse             By: /s/ Robert J. Rinaudo
Name: Jeffrey Grosse               Name: Robert J. Rinaudo
Title: Vice President              Title: Assistant Vice President

ATTEST:                            AMERICAN STOCK TRANSFER & TRUST COMPANY

By: /s/ Susan Silber               By: /s/ Herbert J. Lemmer
Name: Susan Silber                 Name: Herbert J. Lemmer
Title: Assistant Secretary         Title: Vice President<PAGE>

                                                              EXHIBIT 4(d)

                                   [DESIGN]

                                CHEMFIRST INC.
            INCORPORATED UNDER THE LAWS OF THE STATE OF MISSISSIPPI

COMMON STOCK                            CUSIP 16361A 10 6
PAR VALUE $1 PER SHARE                  SEE REVERSE FOR CERTAIN
                                        DEFINITIONS AND INFORMATION

THIS CERTIFIES THAT

IS THE OWNER OF

    FULL-PAID AND NON-ASSESSABLE SHARES, PAR VALUE $1.00 PER SHARE OF THE
                                COMMON STOCK OF

CHEMFIRST INC., transferable on the books of the corporation by the holder
hereof in person or by duly authorized attorney upon surrender of this
certificate property endorsed.  This certificate is not valid unless
countersigned by a Transfer Agent and registered by a Registrar.

     Witness the facsimile seal of the corporation and the facsimile signatures
of its duly authorized officers.

DATED:

/s/ James L. McArthur               /s/ J. Kelley Williams
Secretary                           Chairman of the Board

                                    COUNTERSIGNED AND REGISTERED:
                                    AMERICAN STOCK TRANSFER &
                                    TRUST COMPANY (NEW YORK,
                                    NEW YORK) TRANSFER AGENT AND REGISTRAR

                                    BY

                                    AUTHORIZED SIGNATURE

                                    [SEAL]
<PAGE>

     The following abbreviations, when used in the inscription on the face of
this certificate, shall be construed as through they were written out in full
according to applicable laws or regulations:

     TEN COM - as tenants in common
     UNIF GIFT MIN ACT - ____ Custodian ____ under Uniform Gifts to Minors Act
                        (Cust)        (Minor)
 _____
(State)
     TEN ENT - as tenants by the entireties
     JT TEN - as joint tenants with right of survivorship and not as tenants in
common

     Additional abbreviations may also be used though not in the above list.

     For value received, _____ hereby sell, assign and transfer unto

PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE
______________________   _____________________________________________________

PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS INCLUDING POSTAL ZIP CODE OF ASSIGNEE

________________________________________________________________________________

_______________________________________________________________________ Shares
of the Common Stock represented by the within Certificate, and do hereby
irrevocably constitute and appoint______________________________________________
Attorney to transfer the said stock on the books of the within-named Corporation
with full power of substitution in the premises.

Dated, ______________

                         ______________________________________________

               NOTICE:   THE SIGNATURE TO THIS ASSIGNMENT MUST CORRESPOND WITH
                         THE NAME AS WRITTEN UPON THE FACE OF THE CERTIFICATE,
                         IN EVERY PARTICULAR, WITHOUT ALTERATION OR ENLARGEMENT
                         OR ANY CHANGE WHATEVER.

SIGNATURE(S) GUARANTEED:________________________________________________

                        THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE
                        GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND
                        LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN
                        AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM)
                        PURSUANT TO S.E.C. RULE 17A-d15.
<PAGE>

     This certificate also evidences and entitles the holder hereof to certain
Rights as set forth in the Rights Agreement between ChemFirst Inc. and American
Stock Transfer & Trust Company (the "Rights Agent") dated as of October 30,
1996, as amended from time to time (the "Rights Agreement"), the terms of which
are hereby incorporated herein by reference and a copy of which is on file at
the principal offices of the Company.  Under certain circumstances, as set forth
in the Rights Agreement such Rights will be evidenced by separate certificates
and will no longer be evidenced by this certificate.  The Company will mail to
the holder of this certificate a copy of the Rights Agreement, as in effect on
the date of mailing, without charge promptly after receipt of a written request
thereof.  Under certain circumstances set forth in the Rights Agreement, Rights
issued to, or held by, any Person who is, was or becomes an Acquiring Person, or
an Adverse Person, or any Affiliate or Associate thereof (as such terms are
defined in the Rights Agreement), whether currently held or on behalf of such
person or by any subsequent holder, may become null and void.

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00030-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00030-of-00352.parquet"}]]