AMENDMENT NO. 2


        This Amendment No. 2 dated as of March 26, 1999  ("Agreement")  is among
HydroChem Industrial Services,  Inc., a Delaware corporation  ("Borrower"),  the
banks party to the Credit Agreement described below ("Banks"),  and NationsBank,
N.A.  (successor in interest by merger to NationsBank of Texas,  N.A.), as Agent
for the Banks ("Agent").

                                  INTRODUCTION

        A. The  Borrower,  the Agent and the Banks  are  parties  to the  Credit
Agreement  dated as of December  31,  1997,  as amended by the Letter  Agreement
dated as of March 6, 1998, the Letter Agreement dated as of August 14, 1998, and
Amendment  No. 1 dated as of  September  30,  1998 (as so  amended,  the "Credit
Agreement").

        B. The  Borrower  has  requested  that the Banks  agree to make  certain
amendments to the Credit Agreement.

        C. The Borrower,  as holder of that certain  Promissory Note dated as of
April 9, 1998 made by B. Tom Carter,  Jr. in the principal amount of Two Hundred
Eighty-five  Thousand  Six Hundred- one and No/100  Dollars  ($285,601.00)  (the
"Carter  Note"),  desires to assign  its  rights as holder of the  Carter  Note,
including its right to receive payments thereunder,  to HydroChem Holding, Inc.,
a Delaware  corporation  (such  assignment  is  referred  to herein as the "Note
Assignment"). The Borrower has requested that the Agent and the Banks consent to
the Note Assignment.

        THEREFORE,  the  Borrower,  the  Agent  and the  Banks  hereby  agree as
follows:

        Section 1.  Definitions;  References.  Unless otherwise  defined in this
Agreement,  terms  used  in this  Agreement  which  are  defined  in the  Credit
Agreement  shall  have  the  meanings  assigned  to  such  terms  in the  Credit
Agreement.

        Section 2.  Consent.  The Agent and Banks hereby (a) consent to the Note
Assignment  as  described  above and (b) waive any and all Defaults or Events of
Default that may arise under Section 5.9 of the Credit  Agreement as a result of
the Note  Assignment.  This waiver is limited to the extent described herein and
shall  not be  construed  to be a consent  to or a waiver  of any other  actions
prohibited by the Credit Agreement. The Agent and each of the Banks reserves the
right to exercise any rights and remedies available to it in connection with any
future defaults with respect to Section 5.9 of the Credit Agreement or any other
provision  of any  Credit  Document.  Further,  if the  Note  Assignment  is not
completed as described above, all consents granted hereunder shall be void.





                                        1

<PAGE>



        Section 3.  Amendments.

               (a) Section  1.1.  Section 1.1 is hereby  amended by deleting the
definitions  of "Applicable  Margin" and "EBITDA"  contained in such Section and
replacing them with the following new definitions for such terms:

        "Applicable  Margin" means,  with respect to interest  rates,  letter of
credit  fees and  commitment  fees and as of any date of its  determination,  an
amount  equal to the  percentage  amount per annum set forth in the table  below
opposite the  applicable  Tier set forth below  determined  as a function of the
Leverage Ratio:
<TABLE>
<CAPTION>

                                    Applicable Margin   Applicable   Applicable
      Leverage  Applicable Margin    for Prime Rate     Letter of    Commitment 
Tier    Ratio   for LIBOR Tranche        Tranches       Credit Fees     Fees
----    -----   -----------------        --------       -----------     ----

<S>    <C>            <C>                 <C>              <C>           <C>  
I      x<3.50         1.75%               0.00%            1.75%         0.25%
        -
II     3.50<x<4.00    2.00%               0.25%            2.00%         0.25%
           -
III    4.00<x<4.25    2.25%               0.50%            2.25%         0.30%
           -
IV     4.25<x<4.75    2.50%               0.75%            2.50%         0.375%
           -
V      4.75<x<5.25    2.75%               1.00%            2.75%         0.50%
           -
VI     5.25<x         3.00%               1.00%            3.00%         0.50%
           -
</TABLE>

Beginning  on  the  date  of  this  Agreement  and  until  receipt  of  (i)  the
consolidated  financial  statements of the Borrower for the fiscal quarter ended
March 31, 1999 as required by Section 5.2(b) and (ii) the Compliance Certificate
of the Borrower for such fiscal  quarter,  the Leverage Ratio shall be deemed to
be within Tier IV set forth above. Upon the receipt of such financial statements
and thereafter,  the Agent shall  periodically  determine the Applicable  Margin
based upon the most recent financial  statements of the Borrower dated as of the
end of a fiscal quarter  (including the fourth fiscal quarter)  delivered to the
Agent  pursuant to Section  5.2(b) (and in the case of the fourth fiscal quarter
of each  fiscal  year of the  Borrower,  subject  to  additional  adjustment  in
accordance with the following paragraph based upon audited financial  statements
delivered pursuant to Section 5.2(a)).

Any such adjustments to the Applicable Margin shall become effective on the 45th
day following the last day of each fiscal quarter; provided that; any additional
adjustments to the Applicable Margin shall be made on the 90th day following the
last day of the fourth fiscal quarter of the Borrower;  provided,  further, that
if such  financial  statements are not delivered  when required  hereunder,  the
Applicable  Margin shall increase to the maximum  percentage amount set forth in
the

                                        2

<PAGE>



table above from such 45th day following the last day of the applicable  quarter
until such financial  statements  are received by the Agent.  Upon any change in
the  Applicable  Margin,  the Agent shall  promptly  notify the Borrower and the
Banks of the new Applicable Margin.

        "EBITDA"  means,  with  respect  to any Person and for any period of its
determination,  (a) the  consolidated net income of such Person for such period,
plus (b) to the  extent  the  following  items  are  deducted  for  purposes  of
determining such consolidated net income: (i) the consolidated  interest expense
of such  Person for such  period;  (ii) the  consolidated  income  taxes of such
Person for such period; (iii) the consolidated  depreciation and amortization of
such Person for such period,  and (iv) to the extent such period includes fiscal
quarters  ending  during  fiscal year 1998,  certain  special and  restructuring
charges of such Person in the  amounts set forth for such  quarters as set forth
on Schedule II attached hereto,  minus (c) any interest income and extraordinary
gains of such Person for such period to the extent  included in the  calculation
of such consolidated net income.

               (b) Section 2.1. Section 2.1 is hereby amended by deleting clause
(a) of such Section and replacing it with the following new clause (a):

                      (a) (i)  Revolving Loan Commitments.   Each Bank severally
agrees,  on the terms and  conditions  set forth in this  Agreement  and for the
purposes  set forth in Section  5.4,  to make  Revolving  Loan  Advances  to the
Borrower as such Bank's ratable share of Revolving Loan Borrowings  requested by
the  Borrower  from time to time on any  Business Day during the period from the
date of this Agreement until the Revolving Loan Maturity Date; provided that (i)
the aggregate  outstanding  principal  amount of Revolving Loan Advances made by
such Bank plus such Bank's ratable share of the Letter of Credit  Exposure shall
not  exceed  such  Bank's  Revolving  Loan  Commitment  and (ii)  the  aggregate
outstanding  principal  amount of the Revolving  Loans plus the Letter of Credit
Exposure  plus the  aggregate  outstanding  principal  amount of the  Autoborrow
Advances made pursuant to the Autoborrow  Agreement  shall not exceed the lesser
of (A) the aggregate  Commitments  and (B) the Borrowing  Base.  Revolving  Loan
Borrowings  must be made in an amount  equal to or greater than (X) with respect
to Revolving Loan Advances  bearing  interest based on the Prime Rate,  $100,000
and in integral  multiples of $100,000 in excess thereof and (Y) with respect to
Revolving  Loan  Advances  bearing  interest  based on  LIBOR,  $300,000  and in
integral multiples of $100,000 in excess thereof. Within the limits expressed in
this Agreement,  the Borrower may from time to time borrow, prepay, and reborrow
Revolving  Loan  Borrowings.  The  indebtedness  of the  Borrower  to the  Banks
resulting  from the Revolving Loan Advances made by the Banks shall be evidenced
by Revolving Loan Notes made by the Borrower.
                      (ii)  Reduction  of  Revolving  Loan  Commitments      The
Borrower  shall have the right,  upon at least 30  days'  advance  notice to the
Agent, to reduce  ratably  in  part  or  terminate in whole the  Revolving  Loan
Commitments.  Each such notice shall specify the amount of the

                                        3

<PAGE>



termination or reduction and shall be  irrevocable  and binding on the Borrower.
Partial  reductions  shall be in a minimum  amount of $1,000,000  and be made in
integral multiples of $1,000,000.  In the event of any partial  reduction,  each
Bank's  Revolving Loan Commitment  shall be reduced pro rata. The Revolving Loan
Commitments  cannot be reduced below the amount of the  Revolving  Loan plus the
Letter of Credit Exposure plus the aggregate outstanding principal amount of the
Autoborrow  Advances.  Any  termination  or  reduction  of  the  Revolving  Loan
Commitments  pursuant to this Section  2.1(a)(ii)  shall be  permanent,  with no
obligation of the Banks to reinstate  such reduced or terminated  Revolving Loan
Commitments.

                      (iii) Autoborrow Advances NationsBank has agreed,  subject
to the terms and conditions of this Agreement,  the Autoborrow Agreement and the
Autoborrow  Note, to make  Autoborrow  Advances to the Borrower on or before the
Maturity  Date  (as defined in the  Autoborrow  Note);  provided  that,  (i) the
aggregate outstanding principal amount of  Autoborrow  Advances shall not exceed
$5,000,000  at any  time and  (ii) the aggregate outstanding principal amount of
the  Revolving  Loans  plus  the  Letter of  Credit Exposure  plus the aggregate
outstanding principal amount of the  Autoborrow  Advances  made  pursuant to the
Autoborrow  Agreement  shall  not  exceed  the  lesser  of   (A)  the  aggregate
Commitments and (B) the Borrowing Base.

               (c) Section  2.3.  Section 2.3 is hereby  amended by deleting the
first sentence of clause (b) of such Section and replacing it with the following
new sentence:

                      The  Borrower  shall  pay  to  the  Agent for  the ratable
benefit  of  the  Banks  an  unused  commitment  fee  in  an amount equal to the
Applicable Margin for commitment fees multiplied  by the average daily amount by
which  (i) the aggregate amount of the Revolving  Loan  Commitments exceeds (ii)
the aggregate outstanding principal amount of the Revolving Loan plus the Letter
of  Credit  Exposure  plus  the  aggregate  outstanding  principal amount of the
Autoborrow Advances made pursuant to the Autoborrow Agreement.

               (d) Section 4.19.  The following new Section 4.19 is added to the
Credit Agreement:

                      4.19   Year 2000 Compliance.

               (a) The Borrower has (i) begun  analyzing  the  operations of the
Borrower and its Subsidiaries and Affiliates that could be adversely affected by
failure to become  Year 2000  compliant  (that is, that  computer  applications,
imbedded  microchips  and other  systems will be able to perform date  sensitive
functions  prior to and after  December 31, 1999) and (ii)  developed a plan for
becoming Year 2000 compliant in a timely manner,  the implementation of which is
on schedule in all material respects.  The Borrower  reasonably believes that it
will become Year 2000 compliant

                                        4

<PAGE>



for its  operations  and those of its  Subsidiaries  and  Affiliates on a timely
basis  except to the  extent  that a failure  to do so could not  reasonably  be
expected to have a material  adverse effect upon the financial  condition of the
Borrower.

               (b) The Borrower  reasonably  believes any  suppliers and vendors
that are  material to the  operations  of the Borrower or its  Subsidiaries  and
Affiliates  will be Year 2000  compliant  for their  own  computer  applications
except to the extent that a failure to do so could not reasonably be expected to
have a material adverse effect upon the financial condition of the Borrower.

               (c) The  Borrower  will  promptly  notify  Bank in the  event the
Borrower  determines  that any  computer  application  which is  material to the
operations of the Borrower,  its  Subsidiaries or any of its material vendors or
suppliers will not be fully Year 2000 compliant on a timely basis, except to the
extent that such  failure  could not  reasonably  be expected to have a material
adverse effect upon the financial condition of the Borrower.

               (e)  Section  5.5.  Clauses  (a),  (b) and (d) of Section 5.5 are
hereby  deleted and replaced in their  entirety  with the  following new clauses
(a), (b) and (d):

                             (a) Net Worth.  The  Borrower  shall not permit the
               consolidated Net Worth of the Borrower as of the last day of each
               fiscal quarter to be less than the sum of (i)  $13,000,000,  plus
               (ii) 50% of the cumulative  quarterly  consolidated net income of
               the  Borrower  since  December  31, 1998 for each fiscal  quarter
               ending  after that date during  which the  Borrower  has positive
               consolidated  net  income  plus  (iii)  80% of the  net  proceeds
               resulting  from any sale or issuance of any stock of the Borrower
               or its Subsidiaries since December 31, 1998.

                             (b) Maximum  Funded Debt to Proforma  EBITDA Ratio.
               As of the last day of each fiscal  quarter of the  Borrower,  the
               Borrower  shall  not  permit  the  ratio of (i) the  consolidated
               Funded Debt of the Borrower as of the end of such fiscal  quarter
               to (ii) the consolidated EBITDA of the Borrower for the preceding
               four fiscal  quarters then ended,  to be greater than the maximum
               ratio  set forth in the table  below  for the  applicable  fiscal
               quarter  end set  forth  in the  table  below  (provided  that in
               calculating  the  foregoing,  the  financial  results and balance
               sheet  effects  of any  Acquisitions  may,  if  requested  by the
               Borrower and approved by the Majority Banks  (including  approval
               of any pro  forma  financial  statements),  be  included  in such
               calculations  on a proforma  basis for the full period and on the
               relevant dates.


                                        5

<PAGE>



<TABLE>
<CAPTION>

               Fiscal Quarter Ending On or Before         Maximum Ratio
               ----------------------------------         -------------
                      <S>                                  <C>
                      December 31, 1998                    6.50 to 1.00
                      March 31, 1999                       5.75 to 1.00
                      June 30, 1999                        5.75 to 1.00
                      September 30, 1999                   5.50 to 1.00
                      December 31, 1999                    5.50 to 1.00
                      March 31, 2000                       5.25 to 1.00
                      June 30, 2000                        5.25 to 1.00
                      September 30, 2000                   5.00 to 1.00
                      December 31, 2000                    4.75 to 1.00
</TABLE>

                             (d) Minimum  Interest  Charge Coverage Ratio. As of
               the last day of each  fiscal  quarter,  the  Borrower  shall  not
               permit the ratio of (i) the  consolidated  EBITDA of the Borrower
               for  the  preceding  four  fiscal  quarters  then  ended  to (ii)
               Interest  Charges for the  preceding  four fiscal  quarters  then
               ended to be less  than the  minimum  ratio set forth in the table
               below for the applicable period set forth in the table below.

<TABLE>
<CAPTION>
               Fiscal Quarter Ending On or Before         Minimum Ratio
               ----------------------------------         -------------
                      <S>                                 <C>
                      December 31, 1998                   1.50 to 1.00
                      March 31, 1999                      1.50 to 1.00
                      June 30, 1999                       1.50 to 1.00
                      September 30, 1999                  1.75 to 1.00
                      December 31, 1999                   2.00 to 1.00
                      March 31, 2000                      2.00 to 1.00
                      June 30, 2000                       2.25 to 1.00
                      September 30, 2000                  2.25 to 1.00
                      December 31, 2000                   2.25 to 1.00
</TABLE>

               (f) Exhibits and Schedules. Exhibit C and Exhibit I to the Credit
Agreement are deleted and replaced,  respectively,  with Exhibit C and Exhibit I
hereto. In addition, the new Schedule II attached hereto is added as Schedule II
to the Credit Agreement.

        Section 4.  Representations and Warranties.  The Borrower represents and
warrants to the Agent and the Banks that:



                                        6

<PAGE>



               (a) The  representations  and  warranties set forth in the Credit
Agreement and in the other Credit Documents are true and correct in all material
respects as of the date of this Agreement;

               (b) The execution, delivery and performance of this Agreement are
within the  corporate  power and  authority  of the  Borrower and have been duly
authorized by  appropriate  proceedings  and (ii) this  Agreement  constitutes a
legal,  valid, and binding obligation of the Borrower  enforceable in accordance
with  its  terms,  except  as  limited  by  applicable  bankruptcy,  insolvency,
reorganization,  moratorium,  or similar laws  affecting the rights of creditors
generally and general principles of equity;

               (c) The  Note  Assignment  is  within  the  corporate  power  and
authority  of  the  Borrower  and  has  been  duly   authorized  by  appropriate
proceedings; and

               (d) As of the  effectiveness  of this  Agreement,  no  Default or
Event of Default has occurred and is continuing.

        Section 5.  Effectiveness. This Agreement shall become effective and the
Credit  Agreement  shall  be  amended  as  provided  in  this Agreement upon the
occurrence of the following conditions precedent:

               (a) The Borrower,  the Agent,  and the Banks shall have delivered
duly and validly executed originals of this Agreement to the Agent;

               (b) the representations and warranties in this Agreement shall be
true and correct in all material respects;

               (c) the  Borrower  shall  have  delivered  a  certificate  of its
Secretary  or  Assistant  Secretary,  to  the  extent  required  by  the  Agent,
certifying its certificate of incorporation,  bylaws, resolutions and incumbency
and in form and substance satisfactory to the Agent and the Banks;

               (d) HydroChem Industrial Cleaning,  Inc., a Delaware corporation,
shall have delivered a certificate of its Secretary or Assistant  Secretary,  to
the extent required by the Agent,  certifying its certificate of  incorporation,
bylaws, resolutions and incumbency and in form and substance satisfactory to the
Agent and the Banks;

               (e) HydroChem  Industrial  Cleaning,  Inc.  shall have  delivered
certificates,  to the extent required by the Agent, certifying (i) its existence
and good standing in its state of incorporation  and (ii) its  qualification and
good standing in material jurisdictions where it conducts business;



                                        7

<PAGE>



               (f) HydroChem Industrial  Cleaning,  Inc. shall have executed and
delivered a Joinder  Agreement in  substantially  the form of Exhibit I attached
hereto for the purpose of joining as a party to the Guaranty; and

               (g) the  Borrower  shall  have paid to the  Agent or the  Agent's
designee  (i) a $10,000  amendment  fee and (ii) within 30 days of billing,  all
amounts and expenses  required to be paid in  connection  with the  preparation,
execution  and delivery of this  Agreement and the other  documents  executed in
connection therewith.

        Section 6. Consent of Guarantors.  Each Guarantor hereby consents to the
amendments and  modifications  contained in this Amendment (and the consummation
of the transactions  contemplated  thereby) and confirms that the Guaranty shall
continue to guarantee  the  "Guaranteed  Debt" (as defined in such  Guaranty) as
modified hereby.

        Section 7.  Choice of Law.   This  Agreement  shall  be  governed by and
construed and enforced in accordance with the laws of the State of Texas.

        Section 8.  Counterparts.  This Agreement may be signed in any number of
counterparts, each of which shall be an original.

        PURSUANT TO SECTION  26.02 OF THE TEXAS  BUSINESS AND  COMMERCE  CODE, A
LOAN  AGREEMENT  IN WHICH THE  AMOUNT  INVOLVED  IN THE LOAN  AGREEMENT  EXCEEDS
$50,000 IN VALUE IS NOT ENFORCEABLE  UNLESS THE LOAN AGREEMENT IS IN WRITING AND
SIGNED BY THE PARTY TO BE BOUND OR THAT PARTY'S AUTHORIZED REPRESENTATIVE.

        THE RIGHTS AND OBLIGATIONS OF THE PARTIES TO AN AGREEMENT SUBJECT TO THE
PRECEDING  PARAGRAPH SHALL BE DETERMINED SOLELY FROM THE WRITTEN LOAN AGREEMENT,
AND ANY PRIOR ORAL  AGREEMENTS  BETWEEN THE PARTIES ARE SUPERSEDED BY AND MERGED
INTO THE LOAN AGREEMENT.  THIS WRITTEN  AGREEMENT AND THE CREDIT  DOCUMENTS,  AS
DEFINED IN THE CREDIT AGREEMENT, REPRESENT THE FINAL AGREEMENT AMONG THE PARTIES
AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT
ORAL AGREEMENTS OF THE PARTIES.

        THERE ARE NO UNWRITTEN ORAL AGREEMENTS AMONG THE PARTIES.



                                        8

<PAGE>



     EXECUTED as of the 26th day of March, 1999 and effective as of the 31st day
of December, 1998.
                                            BORROWER:

                                            HYDROCHEM INDUSTRIAL SERVICES, INC.


                                            By:    /s/Selby F. Little, III
                                                   -------------------------
                                            Name:  Selby F. Little, III
                                            Title: Executive Vice President and
                                                   Chief Financial Officer

                                            AGENT:

                                            NATIONSBANK, N.A.


                                            By:   /s/ William T. Griffin
                                                  --------------------------
                                            Name:  William T. Griffin
                                            Title: Vice President


                                            BANKS:

                                            NATIONSBANK, N.A.


                                            By:   /s/ William T. Griffin
                                                  --------------------------
                                            Name:  William T. Griffin
                                            Title: Vice President


                                        9

<PAGE>


Agreed to and Accepted as of the 26th day of March, 1999.


HYDROCHEM INTERNATIONAL, INC.



By:     /s/ Selby F. Little, III
        -------------------------
Name:   Selby F. Little, III
Title:  Executive Vice President and
        Chief Financial Officer


HYDROCHEM INDUSTRIAL CLEANING, INC.


By:     /s/ Selby F. Little, III 
        -------------------------
Name:   Selby F. Little, III
Title:  Executive Vice President and
        Chief Financial Officer

                                       10

<PAGE>



                                                                    Exhibit C


                                        FORM OF
                       BORROWING BASE AND COMPLIANCE CERTIFICATE

                                        [date]



NationsBank, N.A., as Agent
   for the financial institutions parties to the
   Credit Agreement referred to below
700 Louisiana, 7th Floor
Houston, Texas 77002

Attention:  Mr. William T. Griffin, Jr.

Ladies and Gentlemen:

I refer to the Credit  Agreement  dated as of December 31, 1997 (as the same may
be amended, modified, or supplemented from time to time, the "Credit Agreement",
the defined  terms of which are used herein  unless  otherwise  defined  herein)
among  HydroChem  Industrial  Services,  Inc.  (the  "Borrower"),  the financial
institutions parties thereto, and NationsBank of, N.A., successor in interest by
merger to NationsBank of Texas,  N.A., as Agent for such financial  institutions
("Agent").

I hereby certify that I have no knowledge of any Defaults by the Borrower in the
observance of any of the provisions in the Credit  Agreement which existed as of
[_______________] or which exist as of the date of this letter.

I also certify that the accompanying  consolidated  Financial Statements present
fairly, in all material respects,  the consolidated  financial  condition of the
Borrower as of [_______________],  and the related results of operations for the
[_______________]  then ended, in conformity with generally accepted  accounting
principles.

The following sets forth the  information  and  computations  to demonstrate the
calculation  of the Borrowing  Base as of  [______________]  and to  demonstrate
compliance with the  requirements  of Section 5.5 of the Credit  Agreement as of
[_______________]:


                                           1

<PAGE>


<TABLE>
<CAPTION>

<S>                                                                <C>
I.      Borrowing Base

        A.     Eligible Accounts                                   $
                                                                    -----------        

        B.     .85                                                          .85
                                                                    -----------

        C.     Eligible Inventory                                  $
                                                                    -----------

        D.     .60                                                          .60

        E.     Borrowing Base                                      $
               (AxB) + (CxD)                                        -----------

II.     Compliance Certificate

        A.     Section 5.5(a) Net Worth

               1.     $13,000,000                                  $13,000,000 
                                                                    -----------

               2.     50% of  cumulative  quarterly
                      consolidated  net income of
                      Borrower  since  December 31, 1998
                      for each fiscal quarter ending
                      after that date during which
                      Borrower has positive consolidated
                      net income                                   $                    
                                                                    -----------  
               3.     80% of net proceeds resulting from
                      any sale or issuance of any stock
                      of Borrower or its Subsidiaries
                      since December 31, 1998                      $
                                                                    -----------  
               4.     Minimum Net Worth requirement =
                      A.1 + A.2 + A.3                              $               
                                                                    -----------  
               5.     Actual Net Worth                             $                    
                                                                    -----------  

        B.     Section 5.5(b) Maximum Funded Debt to Proforma EBITDA Ratio

               1.     consolidated Funded Debt as of fiscal quarter
                      then ended
                                                                   $
                                                                    -----------             
               2.     consolidated EBITDA for preceding
                      four fiscal quarters
                                                                   $                
                                                                    -----------  
</TABLE>

                                           2

<PAGE>



               3.     ratio B.1 / B.2                              ____ to 1.00

               4.     maximum ratio permitted:
<TABLE>
<CAPTION>
                      Fiscal Quarter Ending On or Before         Maximum Ratio
                      ----------------------------------         -------------
                      <S>                                        <C>
                      December 31, 1998                          6.50 to 1.00
                      March 31, 1999                             5.75 to 1.00
                      June 30, 1999                              5.75 to 1.00
                      September 30, 1999                         5.50 to 1.00
                      December 31, 1999                          5.50 to 1.00
                      March 31, 2000                             5.25 to 1.00
                      June 30, 2000                              5.25 to 1.00
                      September 30, 2000                         5.00 to 1.00
                      December 31, 2000                          4.75 to 1.00
</TABLE>
<TABLE>
<CAPTION>
        <S>                                                        <C>
        C.     Section 5.5(c) Minimum Fixed Charge Coverage Ratio

               1.     consolidated EBITDA for preceding
                      four fiscal quarters                         $                 
                                                                    -----------  
               2.     consolidated cash taxes paid for preceding
                      four fiscal quarters                         $                 
                                                                    -----------  
               3.     Capital Expenditures for preceding
                      four fiscal quarters                         $                 
                                                                    -----------  
               4.     consolidated interest expense for preceding
                      four fiscal quarters                         $                 
                                                                    -----------  
               5.     capitalized interest for preceding
                      four fiscal quarters                         $                 
                                                                    -----------  
               6.     consolidated scheduled principal payments
                      on long term debt(including Capital Leases)
                      for preceding four fiscal quarters           $                 
                                                                    -----------
               7.     cash dividends made in preceding
                      four fiscal quarters                         $                 
                                                                    -----------  


                                           3

<PAGE>


               8.     ratio=(C.1-C.2-C.3)/(C.4+C.5+C.6+C.7)             to 1.00
                                                                    ----

               9.     minimum required:                            1.00 to 1.00

        D.     Section 5.5(d) Minimum Interest Charge Coverage Ratio

               1.     consolidated EBITDA for
                      preceding four fiscal quarters               $                 
                                                                    -----------  
               2.     consolidated interest expense for preceding
                      four fiscal quarters                         $                 
                                                                    -----------  
               3.     capitalized interest for preceding
                      four fiscal quarters                         $                 
                                                                    -----------  
               4.     ratio = (D.1) / (D.2 + D.3)                       to 1.00
                                                                    ----

               5.     minimum ratio required:
</TABLE>
<TABLE>
<CAPTION>
                      Fiscal Quarter Ending On or Before         Minimum Ratio
                      ----------------------------------         -------------
                      <S>                                        <C>
                      December 31, 1998                          1.50 to 1.00
                      March 31, 1999                             1.50 to 1.00
                      June 30, 1999                              1.50 to 1.00
                      September 30, 1999                         1.75 to 1.00
                      December 31, 1999                          2.00 to 1.00
                      March 31, 2000                             2.00 to 1.00
                      June 30, 2000                              2.25 to 1.00
                      September 30, 2000                         2.25 to 1.00
                      December 31, 2000                          2.25 to 1.00
</TABLE>


                                            Very truly yours,

                                            ------------------------
                                            Name:                               
                                            Title:                              

                                           4

<PAGE>


                                                                   Exhibit I


                                     FORM OF
                                JOINDER AGREEMENT
                                  (Subsidiary)


         [Subsidiary], a [ ] corporation (the "Subsidiary"),  hereby agrees with
(a) NationsBank,  N.A., successor in interest by merger to NationsBank of Texas,
N.A.,as Agent for the Banks (the "Agent"),  under the Credit  Agreement dated as
of  December  31,  1997 among  HydroChem  Industrial  Services,  Inc. a Delaware
corporation, the financial institutions parties thereto, as Banks, and the Agent
(as  amended,   modified,  or  supplemented  from  time  to  time,  the  "Credit
Agreement,"  the  capitalized  terms of which are used herein  unless  otherwise
defined herein),  and (b) the other parties to the Guaranty dated as of December
31, 1997 executed in connection with the Credit Agreement, as follows:

         In accordance with Section 5.19 of the Credit Agreement, the Subsidiary
hereby (a) joins the Guaranty as a party thereto and assumes all the obligations
of a Guarantor (as defined in the Guaranty) under the Guaranty, (b) agrees to be
bound  by the  provisions  of the  Guaranty  as if the  Subsidiary  had  been an
original  party to the  Guaranty,  and (c)  confirms  that,  after  joining  the
Guaranty as set forth above, the representations and warranties set forth in the
Credit  Agreement and the Guaranty with respect to the  Subsidiary  are true and
correct in all material respects as of the date of this Joinder Agreement.

         For purposes of notices under the Guaranty,  the notice address for the
Subsidiary is as follows:
 

                  ------------------------
                  ------------------------
                  ------------------------
                  Attention:  ____________
                  Telephone:  (     )________
                  Telecopy:   (     )________

         THIS WRITTEN  AGREEMENT  AND THE CREDIT  DOCUMENTS  REPRESENT THE FINAL
AGREEMENT  AMONG THE PARTIES AND MAY NOT BE  CONTRADICTED  BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

THERE ARE NO UNWRITTEN ORAL AGREEMENTS AMONG THE PARTIES.



<PAGE>


         IN WITNESS WHEREOF this Joinder  Agreement is executed and delivered as
of the ___ day of ________, 19__.

                                           [SUBSIDIARY]



                                            By:    
                                            Name:                
                                            Title:                              






                                       -2-

<PAGE>

                               JOINDER AGREEMENT
                       Hydrochem Industrial Cleaning, Inc.


         HydroChem  Industrial  Cleaning,  Inc.,  a  Delaware  corporation  (the
"Subsidiary"),  hereby agrees with (a) NationsBank,  N.A., successor in interest
by merger to  NationsBank  of Texas,  N.A.,as Agent for the Banks (the "Agent"),
under the  Credit  Agreement  dated as of  December  31,  1997  among  HydroChem
Industrial Services,  Inc. a Delaware  corporation,  the financial  institutions
parties thereto, as Banks, and the Agent (as amended,  modified, or supplemented
from time to time, the "Credit  Agreement," the  capitalized  terms of which are
used herein unless otherwise  defined herein),  and (b) the other parties to the
Guaranty  dated as of December 31, 1997 executed in  connection  with the Credit
Agreement, as follows:

         In accordance with Section 5.19 of the Credit Agreement, the Subsidiary
hereby (a) joins the Guaranty as a party thereto and assumes all the obligations
of a Guarantor (as defined in the Guaranty) under the Guaranty, (b) agrees to be
bound  by the  provisions  of the  Guaranty  as if the  Subsidiary  had  been an
original  party to the  Guaranty,  and (c)  confirms  that,  after  joining  the
Guaranty as set forth above, the representations and warranties set forth in the
Credit  Agreement and the Guaranty with respect to the  Subsidiary  are true and
correct in all material respects as of the date of this Joinder Agreement.

         For purposes of notices under the Guaranty,  the notice address for the
Subsidiary is as follows:

                  c/o HydroChem Industrial Services, Inc.
                  900 Georgia Avenue
                  Deer Park, Texas 77536
                  Attention:        Mr. Selby F. Little
                  Telephone:        (713) 393-5665
                  Telecopy:         (713) 393-5965

         THIS WRITTEN  AGREEMENT  AND THE CREDIT  DOCUMENTS  REPRESENT THE FINAL
AGREEMENT  AMONG THE PARTIES AND MAY NOT BE  CONTRADICTED  BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

THERE ARE NO UNWRITTEN ORAL AGREEMENTS AMONG THE PARTIES.



<PAGE>


         IN WITNESS WHEREOF this Joinder  Agreement is executed and delivered as
of the 26th day of March, 1999.

                                            HYDROCHEM INDUSTRIAL CLEANING, INC.



                                             By:    /s/ Selby F. Little, III   
                                                    --------------------------
                                             Name:  Selby F. Little, III  
                                             Title: Executive Vice President and
                                                    Chief Financial Officer  



                                       -2-

<PAGE>




                                   SCHEDULE II
                                       to
                                   Amendment 2


                        Special and Restructuring Charges
<TABLE>
<CAPTION>
         <S>                                             <C>
         Three months ended:

         June 30, 1998

         Landry Services due diligence                   $    325,000


         December 31, 1998

         Moving expenses                                      290,000
         Year 2000 Compliance program                         200,000
         Cost reduction program                               740,000
                                                              -------
                                                            
                                                         $  1,555,000
                                                            ========
</TABLE>