SECOND AMENDMENT TO CREDIT AGREEMENT

               SECOND AMENDMENT,  dated as of June 30, 2000 (this  "Amendment"),
among HYDROCHEM HOLDING,  INC., a Delaware  corporation  ("Holding"),  HYDROCHEM
INDUSTRIAL  SERVICES,  INC.,  a  Delaware  corporation  (the  "Borrower"),   the
financial  institutions  party to the Credit  Agreement  referred  to below (the
"Lenders"),  and BANK OF AMERICA, N.A., as Administrative Agent. All capitalized
terms used herein and not  otherwise  defined  herein shall have the  respective
meanings provided such terms in the Credit Agreement referred to below.

                              W I T N E S S E T H :
                              --------------------


               WHEREAS,   Holding,   the   Borrower,   the   Lenders   and   the
Administrative Agent are parties to a Credit Agreement, dated as of November 19,
1999 (as in effect on the date hereof, the "Credit Agreement"); and

               WHEREAS, the parties hereto wish to amend the Credit Agreement as
herein provided;

               NOW THEREFORE, it is agreed:


I.      Amendments to Credit Agreement.
        ------------------------------

        1. Section  8.01(f)(A) is hereby  amended by (i) deleting the word "and"
first appearing in the tenth line thereof and inserting a comma in lieu thereof,
(ii)  inserting  the words "and 9.17, in each case"  immediately  after the word
"inclusive," appearing in the same tenth line thereof, and (iii) deleting clause
(iii) thereof and inserting the following new clause (iii) in lieu thereof:

        "(iii) set forth a list of all  Subsidiaries  of the  Borrower as of the
        end of such fiscal quarter or year, as the case may be, and an update to
        Annexes A through F of the Security Agreement and Annexes B through E of
        the Pledge  Agreement as of the end of such fiscal  quarter or year,  as
        the case may be."

        2. Section  8.16(a) is hereby  amended by deleting  the words  "Sections
9.08,  9.09,  9.10 and 9.11" each place such words appear  therein and inserting
the words  "Sections  9.08,  9.09,  9.10, 9.11 and 9.17" in lieu thereof in each
such place.

<PAGE>

        3.  Section 9.10 of the Credit  Agreement is hereby  amended by deleting
such Section in its entirety and by inserting in lieu thereof the  following new
Section 9.10:

               "9.10  Maximum  Consolidated  Leverage  Ratio.  Holding  will not
        permit the Consolidated  Leverage Ratio as of the last day of any fiscal
        quarter of  Holding  ending  during  any  period  set forth  below to be
        greater than the ratio set forth opposite such period below:
<TABLE>
<CAPTION>
               Period                                            Ratio
               ------                                            -----
               <S>                                               <C>
               June 30, 2000 through and
               including December 31, 2000                       5.50:1.00

               January 1, 2001 through and
               including June 30, 2001                           5.25:1.00

               July 1, 2001 through and
               including December 31, 2001                       5.00:1.00

               January 1, 2002 through and
               including December 31, 2002                       4.50:1.00

               January 1, 2003 through and
               including December 31, 2003                       4.00:1.00

               Thereafter                                        3.50:1.00".
</TABLE>

        4.     Section 9  of the  Credit  Agreement is hereby further amended by
inserting  following new Section 9.17 at the end thereof:

               "9.17 Maximum  Consolidated  Senior Leverage Ratio.  Holding will
        not permit the Consolidated  Senior Leverage Ratio as of the last day of
        any fiscal  quarter of Holding  ending during any period set forth below
        to be greater than the ratio set forth opposite such period below:
<TABLE>
<CAPTION>
               Period                                            Ratio
               ------                                            -----
               <S>                                               <C>
               June 30, 2000 through and
               including June 30, 2001                           2.25:1.00

               Thereafter                                        2.00:1.00"
</TABLE>

        5.     Section  11.01  of  the  Credit  Agreement  is  hereby amended by
deleting the definition of "Applicable  Commitment Commission Percentage" and
"Applicable  Margin"  appearing  therein  and  inserting  in  lieu  thereof  the
following  new definition thereof:

                                       2
<PAGE>

               "Applicable  Commitment  Commission  Percentage"  and "Applicable
        Margin"  shall mean from and after any Start Date to and  including  the
        corresponding  End Date, the  respective  percentage per annum set forth
        below under the  respective  column below and  opposite  the  respective
        Level (i.e.,  Level 1, Level 2, Level 3, Level 4, Level 5 or Level 6, as
        the case may be) indicated to have been achieved on the applicable  Test
        Date  for  such  Start  Date  (as  shown  on  the  respective  officer's
        certificate  delivered  pursuant  to  Section  8.01(f)(A)  or the  first
        proviso below):
<TABLE>
<CAPTION>

                                   Applicable                         Applicable
                                   Margin for    Applicable Margin    Commitment
               Consolidated        Base Rate            for           Commission
       Level   Leverage Ratio      Loans         Eurodollar Loans     Percentage
       -----   --------------      -----         ----------------     ----------
         <S>   <C>                     <C>          <C>                 <C>
         1     Less than or equal
               to 2.50:1.00            0.50%        1.75%               0.300%
         2     Greater than
               2.50:1.00 but less
               than or equal to        0.75%        2.00%               0.375%
               3.00:1.00

         3     Greater than
               3.00:1.00 but less
               than or equal to        1.00%        2.25%               0.375%
               3.50:1.00

         4     Greater than
               3.50:1.00 but less
               than or equal to        1.25%        2.50%               0.500%
               4.00:1.00

         5     Greater than
               4.00:1.00 but less
               than or equal to        1.75%        3.00%               0.500%
               5:00:1:00
         6     Greater than            2.25%        3.50%               0.500%
               5.00:1.00
</TABLE>
        ;  provided,  however,  that if Holding  fails to deliver the  financial
        statements  required to be delivered  pursuant to Section 8.01(b) or (c)
        (accompanied  by the  officer's  certificate  required  to be  delivered
        pursuant  to Section  8.01(f)(A)  showing  the  applicable  Consolidated
        Leverage  Ratio on the relevant Test Date) on or prior to the respective
        date required by such  Sections,  then Level 6 pricing shall apply until
        such time,  if any, as the  financial  statements  required as set forth
        above and the  accompanying  officer's  certificate  have been delivered
        showing the pricing for the respective  Margin  Reduction Period is at a
        level which is less than Level 6 (it being  understood that, in the case
        of  any  late  delivery  of  the  financial   statements  and  officer's
        certificate as so required,  any reduction in the Applicable  Commitment

                                       3
<PAGE>

        Commission Percentage and in the Applicable Margin shall apply only from
        and after the date of the delivery of the complying financial statements
        and officer's certificate); provided further, that Level 6 pricing shall
        apply at any time when any Default or Event of Default is in  existence.
        Notwithstanding  anything to the contrary  contained in the  immediately
        preceding  sentence,  (i) for  periods  prior  to the  Second  Amendment
        Effective Date, the Applicable  Commitment Commission Percentage and the
        Applicable  Margin  shall be  determined  as provided in this  Agreement
        prior to giving effect to the Second  Amendment and (ii) Level 5 pricing
        shall apply for the period from the Second  Amendment  Effective Date to
        but not including the date which is the first Start Date after Holding's
        fiscal quarter ending on June 30, 2000."

        6.     Section 11.01 of the Credit  Agreement is hereby further  amended
by  inserting in the proper alphabetical order the following new defined terms:

               "Consolidated Senior Leverage Ratio" shall mean, at any time, the
        ratio of Consolidated  Indebtedness at such time (but excluding from the
        calculation  thereof the aggregate  outstanding  principal amount of all
        Senior Subordinated Notes and Seller Subordinated Notes at such time) to
        Consolidated EBITDA for the Test Period then most recently ended.

               "Second  Amendment" shall mean the Second Amendment,  dated as of
        June 30, 2000, to this Agreement.

               "Second Amendment Effective Date" shall have the meaning provided
in the Second Amendment.

        7.     Section  13.07  of  the  Credit  Agreement is  hereby  amended by
inserting  the words "and Section 9.17," immediately after the word "inclusive,"
appearing in the eighth line thereof.

        8.     Section 13.18 of the Credit Agreement is hereby deleted in its
entirety.


II.     Miscellaneous.
        -------------

        1. In order to induce the Lenders to enter into this Amendment,  each of
Holding  and  the  Borrower   hereby   represents  and  warrants  that  (i)  all
representations,  warranties and agreements contained in Section 7 of the Credit
Agreement are true and correct in all material  respects on and as of the Second
Amendment  Effective Date and as of August 4, 2000 (unless such  representations
and  warranties   relate  to  a  specific  earlier  date,  in  which  case  such
representations  and  warranties  shall  be true  and  correct  in all  material
respects as of such  earlier  date) and (ii) there exists no Default or Event of
Default on the Second Amendment Effective Date and as of August 4, 2000, in each
case after giving effect to this Amendment.

        2. This  Amendment  is limited as specified  and shall not  constitute a
modification,  acceptance  or  waiver  of any  other  provision  of  the  Credit
Agreement or any other Credit Document.

                                       4
<PAGE>

        3. This Amendment may be executed in any number of  counterparts  and by
the  different   parties  hereto  on  separate   counterparts,   each  of  which
counterparts  when executed and delivered  (including by way of facsimile) shall
be an  original,  but all of which shall  together  constitute  one and the same
instrument. A complete set of counterparts shall be lodged with the Borrower and
the Administrative Agent.

        4.  THIS  AMENDMENT  AND  THE  RIGHTS  AND  OBLIGATIONS  OF THE  PARTIES
HEREUNDER  SHALL BE CONSTRUED IN ACCORDANCE  WITH AND GOVERNED BY THE LAW OF THE
STATE OF NEW YORK.

        5. This  Amendment  shall be  effective as of June 30, 2000 (the "Second
Amendment  Effective  Date")  provided  that on or before August 4, 2000 each of
Holding,  the Borrower and the Required  Lenders shall have signed a counterpart
hereof  (whether the same or different  counterparts)  and shall have  delivered
(including,  without limitation, by usage of facsimile transmission) the same to
the Administrative Agent at the Notice Office. This Amendment and the agreements
contained  herein shall be binding on the  successors and assigns of the parties
hereto.

        6. To induce  the  Lenders to enter into this  Amendment,  the  Borrower
hereby agrees to pay to the Administrative Agent (for the account of each Lender
which has  approved  this  Amendment  on or before 5:00 p.m.  (New York time) on
August 4, 2000) an amendment fee equal to 0.20% of the sum of each such Lender's
Revolving Loan Commitment and  outstanding  Term Loans as of the August 4, 2000,
which fee shall be payable on August 7, 2000.

        7. From and after the Second Amendment Effective Date, all references in
the Credit  Agreement and in the other Credit  Documents to the Credit Agreement
shall be deemed to be references to the Credit Agreement as modified hereby.

                                      * * *


                                       5
<PAGE>


               IN  WITNESS  WHEREOF,  each of the  parties  hereto  has caused a
counterpart  of this  Amendment to be duly executed and delivered as of the date
first above written.

                                              HYDROCHEM HOLDING, INC.



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




                                        HYDROCHEM INDUSTRIAL SERVICES, INC.



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



<PAGE>


                                        BANK OF AMERICA, N.A.,
                                        Individually and as Administrative Agent

                                             By:/s/ John J. O'Neill
                                                ----------------------
                                                 Name: John J. O'Neill
                                                 Title: Managing Director




<PAGE>


                                        BANK AUSTRIA CREDITANSTALT
                                          CORPORATE FINANCE, INC.



                                             By:/s/ Gary W. Andresen
                                                -----------------------
                                                 Name: Gary W. Andresen
                                                 Title: Assistant Vice President


                                             By:/s/ Scott Kray
                                                --------------------
                                                 Name: Scott Kray
                                                 Title: Executive Vice President




<PAGE>


                                        NATIONAL CITY BANK OF KENTUCKY



                                             By:/s/ Scott Brewer
                                                ------------------
                                                 Name: Scott Brewer
                                                 Title: Vice President




<PAGE>


                                        NATEXIS BANQUE - BFCE

                                             By:/s/ Daniel Payer
                                                -------------------
                                                 Name: Daniel Payer
                                                 Title: Assistant Vice President


                                             By:/s/ Louis P. Laville, III
                                                ----------------------------
                                                 Name: Louis P. Laville, III
                                                 Title: Vice President and
                                                        Group Manager




<PAGE>


                                        SOUTHWEST BANK OF TEXAS, N.A.



                                             By:/s/ Joe Argue
                                                ----------------
                                                 Name: Joe Argue
                                                 Title: Executive Vice President


                                             By:/s/ Randall Walker
                                                 Name: Randall Walker
                                                 Title: Vice President




<PAGE>


                                        WELLS FARGO BANK (TEXAS),
                                          NATIONAL ASSOCIATION



                                             By:/s/ Linda Masera
                                                -------------------
                                                 Name: Linda Masera
                                                 Title: Vice President