1
                                                                    Exhibit 99

                             LETTER OF TRANSMITTAL
                                      FOR
                          9 7/8% SENIOR NOTES DUE 2008
                                       OF
                               PEN HOLDINGS, INC.
                  PURSUANT TO THE EXCHANGE OFFER IN RESPECT OF
             ALL OF THEIR OUTSTANDING 9 7/8% SENIOR NOTES DUE 2008
                                      FOR
                          9 7/8% SENIOR NOTES DUE 2008
                     PURSUANT TO THE PROSPECTUS DATED 1998

 
        THE EXCHANGE OFFER WILL EXPIRE AT 5:00 P.M., NEW YORK CITY TIME,
  ON                , 1998, OR SUCH LATER DATE AND TIME TO WHICH THE EXCHANGE
                                     OFFER
         MAY BE EXTENDED (THE "EXPIRATION DATE"). TENDERS OF OLD NOTES
                 MAY BE WITHDRAWN PRIOR TO THE EXPIRATION DATE.

                                        
                    To: The Bank of New York, Exchange Agent
 
                        By Registered or Certified Mail,
                           Hand or Overnight Courier
                              The Bank of New York
                               101 Barclay Street
                                 Floor 21 West
                               New York, NY 10286
                     Attention: Corporate Trust Department
                                        
                                  By Facsimile
                     Attention: Corporate Trust Department
                                        
                                        
                              Confirm by Telephone
 
     DELIVERY OF THIS LETTER OF TRANSMITTAL TO AN ADDRESS, OR TRANSMISSION VIA
TELEGRAM, TELEX OR FACSIMILE, OTHER THAN AS SET FORTH ABOVE WILL NOT CONSTITUTE
A VALID DELIVERY. THE INSTRUCTIONS CONTAINED HEREIN SHOULD BE READ CAREFULLY
BEFORE THIS LETTER OF TRANSMITTAL IS COMPLETED.
 
     HOLDERS WHO WISH TO BE ELIGIBLE TO RECEIVE NEW NOTES FOR THEIR OLD NOTES
PURSUANT TO THE EXCHANGE OFFER MUST VALIDLY TENDER (AND NOT WITHDRAW) THEIR OLD
NOTES TO THE EXCHANGE AGENT PRIOR TO THE EXPIRATION DATE.
 
     By execution hereof, the undersigned acknowledges receipt of the Prospectus
(the "Prospectus"), dated           , 1998, of Pen Holdings, Inc. (the
"Issuer"), which, together with this Letter of Transmittal and the Instructions
hereto (the "Letter of Transmittal"), constitute the Issuer's offer (the
"Exchange Offer") to exchange $1,000 principal amount of its 9 7/8% Senior Notes
due 2008 (the "New Notes") that have been registered under the Securities Act of
1933, as amended (the "Securities Act"), pursuant to a Registration Statement of
which the Prospectus constitutes a part, for each $1,000 principal amount of its
outstanding 9 7/8% Senior Notes due 2008 (the "Old Notes"), upon the terms and
subject to the conditions set forth in the Prospectus.
 
     The Company has not entered into any arrangement or understanding with any
person to distribute the New Notes to be received in the Exchange Offer, is
acquiring the New Notes in its ordinary course of business and has no
arrangement or understanding with any person to participate in the distribution
of the New Notes to be received in the Exchange Offer.
 
     This Letter of Transmittal is to be used by Holders if: (i) certificates
representing Old Notes are to be physically delivered to the Exchange Agent
herewith by Holders; (ii) tender of Old Notes is to be made by book-entry
transfer to the Exchange Agent's account at The Depository Trust Company ("DTC")
pursuant to the procedures set forth in the Prospectus under "The Exchange
Offer-Procedures for Tendering" by any financial institution that is a
participant in DTC and whose name appears on a security position listing as the
owner of Old Notes (such participants, acting on behalf of Holders (as
   2
 
defined below), are referred to herein, together with such Holders, as "Acting
Holders"); or (iii) tender of Old Notes is to be made according to the
guaranteed delivery procedures set forth in the Prospectus under "The Exchange
Offer-Guaranteed Delivery Procedures." Delivery of documents to DTC does not
constitute delivery to the Exchange Agent.
 
     The term "Holder" with respect to the Exchange Offer means any person: (i)
in whose name Old Notes are registered on the books of the Issuer or any other
person who has obtained a properly completed bond power from the registered
Holder or (ii) whose Old Notes are held of record by DTC and who desires to
deliver such Old Notes by book entry transfer at DTC.
 
     The undersigned has completed, executed and delivered this Letter of
Transmittal to indicate the action the undersigned desires to take with respect
to the Exchange Offer. Holders who wish to tender their Old Notes must complete
this Letter of Transmittal in its entirety.
 
     All capitalized terms used herein and not defined herein shall have the
meaning ascribed to them in the Prospectus.
 
     The instructions included with this Letter of Transmittal must be followed.
Questions and requests for assistance or for additional copies of the
Prospectus, this Letter of Transmittal and the Notice of Guaranteed Delivery may
be directed to the Exchange Agent. See Instruction 8 herein.
 
     HOLDERS WHO WISH TO ACCEPT THE EXCHANGE OFFER AND TENDER THEIR OLD NOTES
MUST COMPLETE THIS LETTER OF TRANSMITTAL IN ITS ENTIRETY.
 
     List below the Old Notes to which this Letter of Transmittal relates. If
the space provided below is inadequate, list the certificate numbers and
principal amounts on a separately executed schedule and affix the schedule to
this Letter of Transmittal. Tenders of Old Notes will be accepted only in
principal amounts equal to $1,000 or integral multiples thereof.


                                                                                
- --------------------------------------------------------------------------------------------------------------
                                             DESCRIPTION OF OLD NOTES
- --------------------------------------------------------------------------------------------------------------
                                                                                        AGGREGATE PRINCIPAL
                                                              CERTIFICATE NUMBER(S)*      AMOUNT TENDERED
            NAME(S) AND ADDRESS(ES) OF HOLDER(S)              (ATTACH SIGNED LIST IF    (IF LESS THAN ALL)**
                 (PLEASE FILL-IN, IF BLANK                          NECESSARY)
- --------------------------------------------------------------------------------------------------------------
 
                                                             -------------------------------------------------
 
                                                             -------------------------------------------------
 
                                                             -------------------------------------------------
 
                                                             -------------------------------------------------
 
                                                             -------------------------------------------------
 
                                                             -------------------------------------------------
 
                                                             -------------------------------------------------
 
                                                             -------------------------------------------------
 
                                                             -------------------------------------------------
 
                                                             -------------------------------------------------
 
                                                             -------------------------------------------------
 
                                                             -------------------------------------------------
 
- --------------------------------------------------------------------------------------------------------------
 
 TOTAL PRINCIPAL AMOUNT OF OLD NOTES TENDERED
- --------------------------------------------------------------------------------------------------------------
   * Need not be completed by Holders tendering by book-entry transfer.
  ** Need not be completed by Holders who wish to tender with respect to all Old Notes listed. 
     See Instruction 2.
- -------------------------------------------------------------------------------------------------------------

 
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[ ] CHECK HERE IF TENDERED OLD NOTES ARE BEING DELIVERED BY DTC TO THE EXCHANGE
    AGENT'S ACCOUNT AT DTC AND COMPLETE THE FOLLOWING:
 
Name of Tendering Institution:
                               -------------------------------------------------
DTC Book-Entry Account No.:
                            ----------------------------------------------------
Transaction Code No.:
                     -----------------------------------------------------------
 
     If Holders desire to tender Old Notes pursuant to the Exchange Offer and
(i) certificates representing such Old Notes are not lost but are not
immediately available, (ii) time will not permit this Letter of Transmittal,
certificates representing such Old Notes or other required documents to reach
the Exchange Agent prior to the Expiration Date or (iii) the procedures for
book-entry transfer cannot be completed prior to the Expiration Date, such
Holders may effect a tender of such Old Notes in accordance with the guaranteed
delivery procedures set forth in the Prospectus under "The Exchange
Offer-Guaranteed Delivery Procedures."
 
[ ] CHECK HERE IF TENDERED OLD NOTES ARE BEING DELIVERED PURSUANT TO A NOTICE OF
    GUARANTEED DELIVERY PREVIOUSLY DELIVERED TO THE EXCHANGE AGENT AND COMPLETE
    THE FOLLOWING:
 
Name(s) of Holder(s) of Old Notes:
                                   ---------------------------------------------
Window Ticket No. (if any):
                           -----------------------------------------------------
Date of Execution of Notice of Guaranteed Delivery:
                                                   -----------------------------
Name of Eligible Institution that Guaranteed Delivery:
                                                       -------------------------
DTC Book-Entry Account No.:
                           -----------------------------------------------------
If Delivered by Book-Entry Transfer, Name of Tendering Institution:
                                                                    ------------
Transaction Code No.:
                      ----------------------------------------------------------

[ ] CHECK HERE IF YOU ARE A BROKER-DEALER AND WISH TO RECEIVE 10 ADDITIONAL
    COPIES OF THE PROSPECTUS AND 10 COPIES OF ANY AMENDMENTS OR SUPPLEMENTS
    THERETO.
 
Name:
      --------------------------------------------------------------------------
Address:
        ------------------------------------------------------------------------

              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY
 
Ladies and Gentlemen:
 
     Subject to the terms of the Exchange Offer, the undersigned hereby tenders
to the Issuer the principal amount of Old Notes indicated above. Subject to and
effective upon the acceptance for exchange of the principal amount of Old Notes
tendered in accordance with this Letter of Transmittal, the undersigned sells,
assigns and transfers to, or upon the order of, the Issuer all right, title and
interest in and to the Old Notes tendered hereby. The undersigned hereby
irrevocably constitutes and appoints the Exchange Agent and its agent and
attorney-in-fact (with full knowledge that the Exchange Agent also acts as the
agent of the Issuer and as Trustee under the Indenture for the Old Notes and the
New Notes) with respect to the tendered Old Notes with full power of
substitution to (i) deliver certificates for such Old Notes to the Issuer, or
transfer ownership of such Old Notes on the account books maintained by DTC,
together, in either such case, with all accompanying evidences of transfer and
authenticity to, or upon the order of, the Issuer and (ii) present such Old
Notes for transfer on the books of the Issuer and receive all benefits and
otherwise exercise all rights of beneficial ownership of such Old Notes, all in
accordance with the terms of the Exchange Offer. The power of attorney granted
in this paragraph shall be deemed irrevocable and coupled with an interest.
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     The undersigned hereby represents and warrants that he or she has full
power and authority to tender, sell, assign and transfer the Old Notes tendered
hereby and that the Issuer will acquire good and unencumbered title thereto,
free and clear of all liens, restrictions, charges and encumbrances and not
subject to any adverse claim when the same are acquired by the Issuer. The
undersigned also acknowledges that this Exchange Offer is being made in reliance
upon an interpretation by the staff of the Securities and Exchange Commission
that the New Notes issued in exchange for the Old Notes pursuant to the Exchange
Offer may be offered for resale, resold and otherwise transferred by the holders
thereof (other than any such holder that is an "affiliate" of the Issuer within
the meaning of Rule 405 under the Securities Act) without compliance with the
registration and prospectus delivery provisions of the Securities Act, provided
that such New Notes are acquired in the ordinary course of such holders'
business and such holders have no arrangement with any person to participate in
the distribution of such New Notes. The undersigned acknowledges that if he or
she is participating in the Exchange Offer for the purpose of distributing the
New Notes, the undersigned must comply with the registration and prospectus
delivery requirements of the Securities Act in connection with a secondary
resale transaction. If the undersigned is not a broker-dealer, the undersigned
represents that it is not engaged in, and does not intend to engage in, a
distribution of the New Notes. If the undersigned is a broker-dealer that will
receive New Notes for its own account in exchange for Old Notes and the
undersigned represents that such Old Notes were acquired as a result of
market-making activities or other trading activities and acknowledges that it
will deliver a prospectus in connection with any resale of such New Notes, the
undersigned will not be deemed to admit that it is an "underwriter" within the
meaning of the Securities Act.
 
     The undersigned represents that (i) the New Notes acquired pursuant to the
Exchange Offer are being obtained in the ordinary course of such Holder's
business, (ii) such Holder has no arrangements with any person to participate in
the distribution of such New Notes and (iii) such Holder is not an "affiliate,"
as defined under Rule 405 of the Securities Act, of the Issuer or, if such
Holder is an affiliate, that such Holder will comply with the registration and
prospectus delivery requirements of the Securities Act to the extent applicable.
 
     The undersigned will, upon request, execute and deliver any additional
documents deemed by the Exchange Agent or the Issuer to be necessary or
desirable to complete the assignment and transfer of the Old Notes tendered
hereby.
 
     For purposes of the Exchange Offer, the Issuer shall be deemed to have
accepted validly tendered Old Notes when, as and if the Issuer has given oral or
written notice thereof to the Exchange Agent. If any tendered Old Notes are not
accepted for exchange pursuant to the Exchange Offer for any reason,
certificates for any such unaccepted Old Notes will be terminated (except as
noted below with respect to tenders through DTC), without expense, to the
undersigned at the address shown below or at a different address shown below or
at a different address as may be indicated under "Special Issuance Instructions"
as soon as practicable following the Expiration Date.
 
     All authority conferred or agreed to be conferred by this Letter of
Transmittal shall survive the death, incapacity or dissolution of the
undersigned and every obligation under this Letter of Transmittal shall be
binding upon the undersigned's heirs, personal representatives, successors and
assigns.
 
     The undersigned understands that tenders of Old Notes pursuant to the
procedures described under the caption "The Exchange Offer-Procedures for
Tendering" in the Prospectus and in the instructions hereto will constitute a
binding agreement between the undersigned and the Issuer upon the terms and
subject to the conditions of the Exchange Offer.
 
     Unless otherwise indicated under "Special Issuance Instructions," please
issue the certificates representing the New Notes issued in exchange for the Old
Notes accepted for exchange and return any Old Notes not tendered or not
exchanged, in the name(s) of the undersigned (or in such event in the case of
Old Notes tendered by DTC, by credit to the account at DTC). Similarly, unless
otherwise indicated under "Special Delivery Instructions," please send the
certificates representing the New Notes issued in exchange for the Old Notes
accepted for exchange and any certificates for Old Notes not tendered or not
exchanged (and accompanying documents, as appropriate) to the undersigned at the
address shown below the undersigned's signatures, unless, in either event,
tender is being made through DTC. In the event that both "Special Issuance
Instructions" and "Special Delivery Instructions" are completed, please issue
the certificates representing the New Notes issued in exchange for the Old Notes
accepted for exchange and return any Old Notes not tendered or not exchanged in
the name(s) of, and send said certificates to, the person(s) so indicated. The
undersigned recognizes that the Issuer has no obligation pursuant to the
"Special Issuance Instructions" and "Special Delivery Instructions" to transfer
any Old Notes from the name of the registered holder(s) thereof if the Issuer
does not accept for exchange any of the Old Notes so tendered.
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                                PLEASE SIGN HERE
 
       (TO BE COMPLETED BY ALL TENDERING HOLDERS OF OLD NOTES REGARDLESS
         OF WHETHER OLD NOTES ARE BEING PHYSICALLY DELIVERED HEREWITH)
 
     This Letter of Transmittal must be signed by the Holder(s) of Old Notes
exactly as their name(s) appear(s) on certificate(s) for Old Notes or, if
tendered by a participant in, exactly as such participant's name appears on a
security position listing as the owner of Old Notes, or by person(s) authorized
to become registered Holder(s) by endorsements and documents transmitted with
this Letter of Transmittal. If signature is by a trustee, executor,
administrator, guardian, attorney-in-fact, officer or other person acting in a
fiduciary or representative capacity, such person must set forth his or her full
title below under "Capacity" and submit evidence satisfactory to the Issuer of
such person's authority to so act. See Instruction 3 herein.
 
     If the signature appearing below is not of the registered Holder(s) of the
Old Notes, then the registered Holder(s) must sign a valid proxy.
 

                                                
 
X                                                  Date:
 ----------------------------------------------         ---------------------------------------

X                                                  Date:
 ----------------------------------------------         ---------------------------------------
SIGNATURE(S) OF HOLDER(S) OR                       Address:
AUTHORIZED SIGNATORY                                       ------------------------------------

Name(s):                                                   -----------------------------------
        --------------------------------------                   (INCLUDING ZIP CODE)
                                                   Area Code and Telephone No.:
        --------------------------------------                                  ---------------
         (PLEASE PRINT)

Capacity:
          ------------------------------------
Social Security No.:
                     -------------------------

 
                 SIGNATURE GUARANTEE (SEE INSTRUCTION 3 HEREIN)
        CERTAIN SIGNATURES MUST BE GUARANTEED BY AN ELIGIBLE INSTITUTION
 
- --------------------------------------------------------------------------------
             (NAME OF ELIGIBLE INSTITUTION GUARANTEEING SIGNATURES)
 
- --------------------------------------------------------------------------------
               (ADDRESS (INCLUDING ZIP CODE) AND TELEPHONE NUMBER
                         (INCLUDING AREA CODE) OF FIRM)
 
- --------------------------------------------------------------------------------
                             (AUTHORIZED SIGNATURE)
 
- --------------------------------------------------------------------------------
                                 (PRINTED NAME)
 
- --------------------------------------------------------------------------------
                                    (TITLE)
 
Date:

      ------------------------
   6
 
                         SPECIAL ISSUANCE INSTRUCTIONS
                       (SEE INSTRUCTIONS 3 AND 4 HEREIN)
 
    To be completed ONLY if certificates for Old Notes in a principal amount not
tendered are to be issued in the name of, or the New Notes issued pursuant to
the Exchange Offer are to be issued to the order of, someone other than the
person or persons whose signature(s) appear(s) within this Letter of Transmittal
or issued to an address different from that shown in the box entitled
"Description of Old Notes" within this Letter of Transmittal, or if Old Notes
tendered by book-entry transfer that are not accepted for purchase are to be
credited to an account maintained at DTC.
 
Name:
     ------------------------------------------------------------------------
                                    (Please Print)
 
Address:
        ---------------------------------------------------------------------
                                     (Please Print)

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

- ----------------------------------------------------------------------------- 
                                   (Zip Code)
 
- ----------------------------------------------------------------------------- 
              (Taxpayer Identification or Social Security Number)
 


                         SPECIAL DELIVERY INSTRUCTIONS
                       (SEE INSTRUCTIONS 3 AND 4 HEREIN)
 
    To be completed ONLY if Certificates for Old Notes in a principal amount not
tendered or not accepted for purchase or the New Notes issued pursuant to the
Exchange Offer are to be sent to someone other than the person or persons whose
signature(s) appear(s) within this Letter of Transmittal or to an address
different from that shown in the box entitled "Description of Old Notes" within
this Letter of Transmittal.
 
Name:
     ------------------------------------------------------------------------
                                    (Please Print)
 
Address:
        ---------------------------------------------------------------------
                                     (Please Print)

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

- ----------------------------------------------------------------------------- 
                                   (Zip Code)

- -----------------------------------------------------------------------------  
                (Taxpayer Identification or Social Security No.)
   7
 
                                  INSTRUCTIONS
         FORMING PART OF THE TERMS AND CONDITIONS OF THE EXCHANGE OFFER
 
     1. DELIVERY OF THIS LETTER OF TRANSMITTAL AND OLD NOTES. The certificates
for the tendered Old Notes (or a confirmation of a book-entry into the Exchange
Agent's account at DTC of all Old Notes delivered electronically), as well as a
properly completed and duly executed copy of this Letter of Transmittal or
facsimile hereof and any other documents required by this Letter of Transmittal
must be received by the Exchange Agent at its address set forth herein prior to
5:00 p.m., New York City time, on the Expiration Date. The method of delivery of
the tendered Old Notes, this Letter of Transmittal and all other required
documents to the Exchange Agent is at the election and risk of the Holder and,
except as otherwise provided below, the delivery will be deemed made only when
actually received by the Exchange Agent. Instead of delivery by mail, it is
recommended that the Holder use an overnight or hand delivery service. In all
cases, sufficient time should be allowed to assume timely delivery. No Letter of
Transmittal or Old Notes should be sent to the Issuer.
 
     Holders who wish to tender their Old notes and (i) whose Old Notes are not
immediately available or (ii) who cannot deliver their Old Notes, this Letter of
Transmittal or any other documents required hereby to the Exchange Agent prior
to the Expiration Date must tender their Old Notes and follow the guaranteed
delivery procedures set forth in the Prospectus. Pursuant to such procedures:
(i) such tender must be made by or through an Eligible Institution; (ii) prior
to the Expiration Date, the Exchange Agent must have received from the Eligible
Institution a properly completed and duly executed Notice of Guaranteed Delivery
(by facsimile transmission, mail or hand delivery) setting forth the name and
address of the Holder of the Old Notes, the certificate number or numbers of
such Old Notes and the principal amount of Old Notes tendered, stating that the
tender is being made thereby and guaranteeing that, within five business days
after the Expiration Date, this Letter of Transmittal (or facsimile thereof)
together with the certificate(s) representing the Old Notes (or a confirmation
of electronic delivery of book-entry delivery into the Exchange Agent's account
at DTC) and any of the required documents will be deposited by the Eligible
Institution with the Exchange Agent; and (iii) such properly completed and
executed Letter of Transmittal (or facsimile hereof), as well as all other
documents required by this Letter of Transmittal and the certificate(s)
representing all tendered Old Notes in proper form for transfer (or a
confirmation of electronic mail delivery of book-entry delivery into the
Exchange Agent's account at DTC), must be received by the Exchange Agent within
five business days after the Expiration Date, all as provided in the Prospectus
under the caption "Guaranteed Delivery Procedures." Any Holder of Old Notes who
wishes to tender his Old Notes pursuant to the guaranteed delivery procedures
described above must ensure that the Exchange Agent receives the Notice of
Guaranteed Delivery prior to 5:00 p.m., New York City time, on the Expiration
Date.
 
     All questions as to the validity, form, eligibility (including time of
receipt), acceptance and withdrawal of tendered Old Notes will be determined by
the Issuer in its sole discretion, which determination will be final and
binding. The Issuer reserves the absolute right to reject any and all Old Notes
not properly tendered or any Old Notes the Issuer's acceptance of which would,
in the opinion of counsel for the Issuer, be unlawful. The Issuer also reserves
the right to waive any irregularities or conditions of tender as to particular
Old Notes. The Issuer's interpretation of the terms and conditions of the
Exchange Offer (including the instructions in this Letter of Transmittal) will
be final and binding on all parties. Unless waived, any defects or
irregularities in connection with tenders of Old Notes must be cured within such
time as the Issuer shall determine. Neither the Issuer, the Exchange Agent nor
any other person shall be under any duty to give notification of defects or
irregularities with respect to tenders of Old Notes, nor shall any of them incur
any liability for failure to give such notification. Tenders of Old Notes will
not be deemed to have been made until such defects or irregularities have been
cured or waived. Any Old Notes received by the Exchange Agent that are not
properly tendered and as to which the defects or irregularities have not been
cured or waived will be returned without cost by the Exchange Agent to the
tendering Holders of Old Notes, unless otherwise provided in this Letter of
Transmittal, as soon as practicable following the Expiration Date.
 
     2. PARTIAL TENDERS. Tenders of Old Notes will be accepted in all
denominations of $1,000 and integral multiples in excess thereof. If less than
the entire principal amount of any Old Notes is tendered, the tendering Holders
should fill in the principal amount tendered in the third column of the chart
entitled "Description of Old Notes." The entire principal amount of Old Notes
delivered to the Exchange Agent will be deemed to have been tendered unless
otherwise indicated. If the entire principal amount of all Old Notes is not
tendered, Old Notes for the principal amount of Old Notes delivered to the
Exchange Agent will be deemed to have been tendered unless otherwise indicated.
If the entire principal amount of all Old Notes is not tendered, Old Notes for
the principal amount of Old Notes not tendered and a certificate or certificates
representing New Notes issued in exchange of any Old Notes accepted will be sent
to the Holder at his or her registered address, unless a
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different address is provided in the appropriate box on this Letter of
Transmittal or unless tender is made through DTC, promptly after the Old Notes
are accepted for exchange.
 
     3. SIGNATURES ON THE LETTER OF TRANSMITTAL; BOND POWERS AND ENDORSEMENTS;
GUARANTEE OF SIGNATURES. If this Letter of Transmittal (or facsimile hereof) is
signed by the registered Holder(s) of the Old Notes tendered hereby, the
signature must correspond with the name(s) as written on the face of the Old
Notes without alteration, enlargement or any change whatsoever.
 
     If this Letter of Transmittal (or facsimile hereof) is signed by the
registered Holder(s) of Old Notes tendered and the certificate(s) for New Notes
issued in exchange thereof is to be issued (or any untendered principal amount
of Old Notes is to be reissued) to the registered Holder, such Holder need not
and should not endorse any tendered Old Note, nor provide a separate bond power.
In any other case, such Holder must either properly endorse the Old Notes
tendered or transmit a properly completed separate bond power with this Letter
of Transmittal, with the signatures on the endorsement or bond power guaranteed
by an Eligible Institution.
 
     If this Letter of Transmittal (or facsimile hereof) or any Old Notes or
bond powers are signed by trustees, executors, administrators, guardians,
attorneys-in-fact, or officers of corporations or others acting in a fiduciary
or representative capacity, such persons should so indicate when signing, and
unless waived by the Issuer, evidence satisfactory to the Issuer of their
authority so to act must be submitted with this Letter of Transmittal.
 
     Endorsements on Old Notes or signatures on bond powers required by this
Instruction 3 must be guaranteed by an Eligible Institution.
 
     Signatures on this Letter of Transmittal (or facsimile hereof) must be
guaranteed by an Eligible Institution unless the Old Notes tendered pursuant
thereto are tendered (i) by a registered Holder (including any participant in
DTC whose name appears on a security position listing as the owner of Old Notes)
who has not completed the box set forth herein entitled "Special Issuance
Instructions" or the box entitled "Special Delivery Instructions" or (ii) for
the account of an Eligible Institution.
 
     4. SPECIAL ISSUANCE AND DELIVERY INSTRUCTIONS. Tendering Holders should
indicate, in the applicable spaces, the name and address to which New Notes or
substitute Old Notes for principal amounts not tendered or not accepted for
exchange are to be issued or sent, if different from the name and address of the
person signing this Letter of Transmittal (or in the case of tender of the Old
Notes through DTC, if different from DTC). In the case of issuance in a
different name, the taxpayer identification or social security number of the
person named must also be indicated.
 
     5. TRANSFER TAXES. The Issuer will pay all transfer taxes, if any,
applicable to the exchange of Old Notes pursuant to the Exchange Offer. If,
however, certificates representing New Notes or Old Notes for principal amounts
not tendered or accepted for exchange are to be delivered to, or are to be
registered or issued in the name of, any person other than the registered Holder
of the Old Notes tendered hereby, or if tendered Old Notes are registered in the
name of any person other than the person signing this Letter of Transmittal, or
if a transfer tax is imposed for any reason other than the exchange of Old Notes
pursuant to the Exchange Offer, then the amount of any such transfer taxes
(whether imposed on the registered Holder or any other person) will be payable
by the tendering Holder. If satisfactory evidence of payment of such taxes or
exemption therefrom is not submitted with this Letter of Transmittal, the amount
of such transfer taxes will be billed directly to such tendering Holder
 
     EXCEPT AS PROVIDED IN THIS INSTRUCTION 5, IT WILL NOT BE NECESSARY FOR
TRANSFER TAX STAMPS TO BE AFFIXED TO THE OLD NOTES LISTED IN THIS LETTER OF
TRANSMITTAL.
 
     6. WAIVER OF CONDITIONS. The Issuer reserves the absolute right to amend,
waive or modify specified conditions in the Exchange Offer in the case of any
Old Notes tendered.
 
     7. MUTILATED, LOST, STOLEN OR DESTROYED OLD NOTES. Any tendering Holder
whose Old Notes have been mutilated, lost, stolen or destroyed should contact
the Exchange Agent at the address indicated herein for further instruction.
 
     8. REQUESTS FOR ASSISTANCE OR ADDITIONAL COPIES. Questions and requests for
assistance and requests for additional copies of the Prospectus or this Letter
of Transmittal may be directed to the Exchange Agent at the address specified in
the Prospectus. Holders may also contact their broker, dealer, commercial bank,
trust company or other nominee for assistance concerning the Exchange Offer.
   9
 
                         (DO NOT WRITE IN SPACE BELOW)
 

                                                                        
- --------------------------------------------------------------------------------------------------------------------
       CERTIFICATE SURRENDERED                   OLD NOTES TENDERED                     OLD NOTES ACCEPTED
- --------------------------------------------------------------------------------------------------------------------
 
- --------------------------------------------------------------------------------------------------------------------
 
- --------------------------------------------------------------------------------------------------------------------
 
- --------------------------------------------------------------------------------------------------------------------
 
- --------------------------------------------------------------------------------------------------------------------
 
  DELIVERY PREPARED BY                           CHECK   BY                             DATE 
                       ------------------------             --------------------------       ----------------------

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

   10
 
                         NOTICE OF GUARANTEED DELIVERY
 
                                 FOR TENDER OF
 
                          9 7/8% SENIOR NOTES DUE 2008
 
                               (THE "OLD NOTES")
 
                                       OF
 
                               PEN HOLDINGS, INC.
 
     This form, or one substantially equivalent hereto, must be used to tender
Old Notes pursuant to the Exchange Offer described in the Prospectus dated
            , 1998 (the "Prospectus") of Pen Holdings, Inc. (the "Company"), if
a holder of Old Notes cannot either deliver a Letter of Transmittal to the
Exchange Agent listed below (the "Exchange Agent") or cannot deliver the Old
Notes to be tendered or complete the procedure for book-entry transfer prior to
5:00 P.M., New York City time, on             , 1998 or such later date and time
to which the Exchange Offer may be extended (the "Expiration Date"). This form,
or one substantially equivalent hereto, must be delivered by hand or sent by
facsimile transmission or mail to the Exchange Agent, and must be received by
the Exchange Agent on or prior to the Expiration Date. See "The Exchange
Offer--Procedures for Tendering" in the Prospectus. Capitalized terms used
herein and not defined herein shall have the meanings ascribed thereto in the
Prospectus.
 
                    TO: THE BANK OF NEW YORK, EXCHANGE AGENT
 
                    By Mail, by Hand or Overnight Delivery:
                              The Bank of New York
                               101 Barclay Street
                                 Floor 21 West
                               New York, NY 10286
                        Attn: Corporate Trust Department
 
                                 By Facsimile:
                     Attention: Corporate Trust Department
                         (     )           -
 
                             Confirm by Telephone:
                         (     )           -
 
     DELIVERY OF THIS INSTRUMENT TO AN ADDRESS OTHER THAN AS SET FORTH ABOVE OR
TRANSMISSION OF INSTRUCTIONS VIA FACSIMILE OTHER THAN AS SET FORTH ABOVE DOES
NOT CONSTITUTE A VALID DELIVERY.
   11
 
Ladies and Gentlemen:
 
     The undersigned hereby represent that he or she is the holder of the Old
Notes indicated below and that the Letter of Transmittal cannot be delivered to
the Exchange Agent and/or either the certificates representing such Old Notes
cannot be delivered to the Exchange Agent or the procedure for book-entry
transfer cannot be completed prior to the Expiration Date. The undersigned
hereby tenders the Old Notes indicated below pursuant to the guaranteed delivery
procedures set forth in the Prospectus and the Letter of Transmittal, receipt of
which is hereby acknowledged.
 
Name(s) of Tender Holder(s):
                              -----------------------------------------------

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                              PLEASE PRINT OR TYPE
 
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                                   SIGNATURE
 
Address(es):
            -----------------------------------------------------------------
 
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Telephone Number(s):
                     --------------------------------------------------------
 
Name(s) in which Old Notes are registered:
                                          ---------------------------------- 


                                                      
- -----------------------------------------------------------------------------------------------------------------
          CERTIFICATE NO(S). (IF APPLICABLE)*                          PRINCIPAL AMOUNT TRANSFERRED
- -----------------------------------------------------------------------------------------------------------------
 
- -----------------------------------------------------------------------------------------------------------------
 
- -----------------------------------------------------------------------------------------------------------------
 
- -----------------------------------------------------------------------------------------------------------------
 
- -----------------------------------------------------------------------------------------------------------------
 
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* Need not be completed by book-entry holders.
   12
 
                             GUARANTEE OF DELIVERY
                    (NOT TO BE USED FOR SIGNATURE GUARANTEE)
 
     The undersigned, a member firm of a registered national securities exchange
or of the National Association of Securities Dealers, Inc., a commercial bank or
trust company having an office or a correspondent in the United States or an
"eligible guarantor institution" within the meaning of Rule 17Ad-15 under the
Securities Exchange Act of 1934, as amended, hereby guarantees that the
undersigned will deliver to the Exchange Agent the certificates representing the
Old Notes being tendered hereby in proper form for transfer (or a confirmation
of book-entry transfer of such Old Notes, into the Exchange Agent's account at
the book-entry transfer facility) with delivery of a properly completed and duly
executed Letter of Transmittal (or facsimile thereof), with any required
signature guarantees and any other required documents, all within five business
days after the Expiration Date.
 

                                                  
Name of Firm                                                                                    
             ---------------------------------       -------------------------------------------
                                                                Authorized Signature
Address                                              Name
       ---------------------------------------           ---------------------------------------
                                                                Please Print or Type
- ----------------------------------------------
                 Zip Code                            Title
                                                           -------------------------------------
Telephone No.                                        Dated
              --------------------------------             -------------------------------------



 
     The institution that completes this form must communicate the guarantee to
the Exchange Agent and must deliver the certificates representing any Old Notes
(or a confirmation of book-entry transfer of such Old Notes into the Exchange
Agent's account at the book-entry transfer facility) and the Letter of
Transmittal to the Exchange Agent within the time period shown herein. Failure
to do so could result in a financial loss to such institution.