EX 10.16
May 10, 2001


Mr. Dennis L. Yakobson
President and Chief Executive Officer
Rentech, Inc.
1331 17th Street, Suite 720
Denver, CO 80202

Dear Dennis:

         This letter confirms our understanding that Rentech, Inc. ("Rentech" or
the "Company") has engaged Petrie Parkman & Co., Inc. ("Petrie  Parkman") as its
exclusive  financial advisor to render financial advisory and investment banking
services to the Company in connection  with a possible  financing of the Company
through the sale of equity  securities  (including  any class of common stock or
securities  convertible  into or exchangeable  for any class of common stock) of
Rentech or its affiliates or successors in a private placement (the "lacement").

Services
         In  connection  with its role as  financial  advisor and as part of its
efforts to help Rentech achieve its corporate objectives, Petrie Parkman will be
available to:

         1. Meet with  Rentech  management  to develop an  understanding  of the
Company' strategic objectives;
         2. Meet with the management and any  consultants,  as  appropriate,  to
allow Petrie Parkman to gain a thorough understanding of the Company' assets;
         3.  Assist  Rentech in the  preparation  of  marketing  and  disclosure
materials;
         4.  Assist  the  Company  in  preparing  for  meetings  with  potential
investors;
         5.  Advise and assist  Rentech  in the  course of its  negotiation  and
closing of a Placement; and
         6.  Prepare  and  deliver  presentations  to  the  Company's  Board  of
Directors regarding a possible Placement.

Fee Structure
         In consideration for our role as financial advisor,  the Company agrees
to compensate Petrie Parkman as follows:

         If while this engagement is in effect or within twelve months following
the  termination  of this  agreement,  the Company has entered  into a letter of
intent or a definitive agreement or is engaged in substantive negotiations,  any
of which lead to a  Placement,  the  Company  agrees to pay Petrie  Parkman,  at
closing,  a fee equal to 2.5% of the gross proceeds  received from the Placement
(the "Transaction Fee").

         The  Company   also  agrees  to  reimburse   Petrie   Parkman  for  its
out-of-pocket  expenses related to this assignment,  including fees and expenses
of counsel.

  Coordination
         In order to  coordinate  efforts of the Company  and Petrie  Parkman to
effect the Placement in the most  professional  and efficient  manner  possible,
during the period of Petrie  Parkman's  engagement,  neither the Company nor its
management  will initiate any discussion  with potential  investors  without the
prior  knowledge  of  Petrie  Parkman.  In the  event  that the  Company  or its



management  receives any inquiry or are  otherwise  aware of the interest of any
third party concerning a purchase of equity pursuant to the Placement, they will
promptly inform Petrie Parkman of such inquiry.

  Confidential Information
         Petrie  Parkman  acknowledges  that it will be  provided  with  certain
confidential information regarding the Company (the "Confidential  Information")
and that it will not use the Confidential Information except as may be necessary
in connection with rendering its services as financial advisor to the Company or
as may be required by law.

  Indemnification
         Since  Petrie  Parkman  will be  acting on  behalf  of the  Company  in
connection  with its engagement  hereunder,  the Company and Petrie Parkman have
entered into a separate letter agreement,  dated the date hereof,  providing for
the  indemnification  by the  Company  of Petrie  Parkman  and  certain  related
entities.

  Termination
         It is understood  that our services may be  terminated  with or without
cause by us or by you upon  notice  to the other  party at any time and  without
liability or continuing  obligation to us or to you (except for any compensation
earned pursuant to the fee structure  described above, and any expenses incurred
by us up to the date of termination  as described  above).  Notwithstanding  the
foregoing,  the indemnity  provisions of this agreement  shall remain  operative
regardless of any such termination.

         If the  foregoing is in  accordance  with your  understanding,  I would
appreciate  you signing  and  returning  to us the  enclosed  duplicate  of this
letter.

         We sincerely look forward to working with you on this assignment.

                 Very truly yours,

                 PETRIE PARKMAN & CO., INC.


                 By:  M.E. Bock
AGREED TO:

RENTECH, INC.


By: Dennis L. Yakobson


May 10, 2001


Petrie Parkman & Co., Inc.
475 17th Street
Denver, CO 80202

Gentlemen:

         In connection  with your engagement to advise and assist us pursuant to
the  engagement  letter  dated  hereof (the  "Agreement"),  Rentech,  Inc.  (the
"Company")  hereby agrees to indemnify and hold harmless  Petrie  Parkman & Co.,
Inc.  ("Petrie  Parkman"),  which for  purposes of this  agreement  includes its
affiliates, the respective directors,  officers,  partners, agents and employees
of Petrie Parkman and its affiliates and each  controlling  person (as such term



is defined under the  Securities  Act of 1933,  as amended),  to the full extent
lawful,  from and against all losses,  claims,  damages,  liabilities,  joint or
several (and all actions,  claims,  proceedings  and  investigations  in respect
thereof),  and expenses  incurred by them (including fees and  disbursements  of
counsel)  which (A) are related to or arise out of (i) actions  taken or omitted
to be taken (including any untrue  statements made or any statements  omitted to
be made) by the Company or (ii)  actions  taken or omitted to be taken by Petrie
Parkman with our consent or in  conformity  with our actions or omissions or (B)
are  otherwise  related to or arise out of Petrie  Parkman's  activities  on our
behalf under Petrie Parkman's  engagement,  and we will reimburse Petrie Parkman
for all  expenses  (including  fees and  disbursements  of  counsel) as they are
incurred  by Petrie  Parkman in  connection  with  investigating,  preparing  or
defending any such action or claim, whether or not in connection with pending or
threatened  litigation  in  which  Petrie  Parkman  is a  party.  We will not be
responsible,  however, for any losses, claims, damages,  liabilities or expenses
pursuant to clause (B) of the preceding  sentence  which are finally  judicially
determined to have resulted  primarily from the bad faith or gross negligence of
the person seeking indemnification  hereunder. We also agree that Petrie Parkman
shall not have any  liability to us for or in  connection  with such  engagement
except for such liability for losses, claims,  damages,  liabilities or expenses
incurred by us which is finally judicially determined to have resulted primarily
from  Petrie  Parkman's  bad faith or gross  negligence.  If for any  reason the
foregoing  indemnification  (including the  reimbursement  provisions  described
above) or exculpation is unavailable to Petrie Parkman or  insufficient  to hold
it harmless,  then the Company shall contribute to the amount paid or payable by
Petrie  Parkman as a result of such loss,  claim,  damage or  liability  in such
proportion as is appropriate to reflect not only the relative  benefits received
(or  anticipated  to be  received)  by the  Company  on the one hand and  Petrie
Parkman on the other hand but also the relative  fault of the Company and Petrie
Parkman as well as any relevant equitable  considerations,  provided, that in no
event will Petrie Parkman's aggregate  contribution  hereunder exceed the amount
of fees actually paid to Petrie Parkman in respect of the subject matter of such
loss,  claim,  damage or liability  pursuant to the  Agreement.  The  indemnity,
exculpation,  reimbursement  and  contribution  obligations of the Company under
this  paragraph  shall be in  addition  to any  liability  which the Company may
otherwise  have,  shall  survive any  termination  of the Agreement and shall be
binding  upon and extend to the benefit of any  successors,  assigns,  heirs and
personal  representatives  of the  Company  and Petrie  Parkman.  If any action,
claim,  proceeding or investigation  is instituted or threatened  against Petrie
Parkman  in  respect  of which  indemnity  may be  sought  against  the  Company
hereunder,  Petrie Parkman shall promptly notify the Company thereof in writing,
but the omission to so notify the Company shall not relieve the Company from any
obligation or liability  that the Company may have to Petrie  Parkman under this
letter or otherwise. Petrie Parkman will have the right to retain counsel of its
choice to represent  Petrie Parkman in connection  with any such action,  claim,
proceeding  or  investigation,  provided  that such counsel  shall be reasonably
satisfactory  to the Company.  Notwithstanding  anything to the contrary  above,
Petrie Parkman shall not have any obligation to provide notice to the Company as
to any action, claim,  proceeding or investigation in which the Company is named
a defendant.  We also agree that we will not,  without the prior written consent
of Petrie Parkman,  settle or compromise or consent to the entry of any judgment
in any pending or  threatened  claim,  action,  suit or proceeding in respect of
which  indemnification may be sought hereunder (whether or not Petrie Parkman is
an actual or potential party to such claim,  action,  suit or proceeding) unless



such  settlement,  compromise or consent  includes an  unconditional  release of
Petrie  Parkman from all liability  arising out of such claim,  action,  suit or
proceeding.  We hereby consent to personal jurisdiction and service and venue in
any court in which any claim  which is  subject  to this  agreement  is  brought
against Petrie Parkman or any other indemnified person.

         It  is   understood   that,  in   connection   with  Petrie   Parkman's
above-mentioned engagement,  Petrie Parkman may also be engaged to act for us in
one or more additional capacities, and that the terms of the original engagement
or any  such  additional  engagement  may be  embodied  in one or more  separate
written agreements. This indemnification shall apply to the original engagement,
any such additional  engagement and any modification of the original  engagement
or such  additional  engagement  and  shall  remain  in full  force  and  effect
following the completion or termination of Petrie Parkman's engagement(s).

         We further  understand that if Petrie Parkman is asked to act for us in
any other  formal  capacity,  such  further  action may be subject to a separate
agreement containing provisions and terms to be mutually agreed upon.

            Very truly yours,

            RENTECH, INC.

            By: Dennis L. Yakobson

Agreed to and Accepted:


PETRIE PARKMAN & CO., INC.

By: M.E. Bock