THIRD AMENDMENT TO CREDIT AGREEMENT



                 THIRD AMENDMENT, dated as of June 30, 2001  (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  and modify the
Credit Agreement as herein provided;

                 NOW THEREFORE, it is agreed:


I.       Amendments and Agreement to Credit Agreement.

         1.      Section  9.07(a) of the Credit  Agreement is hereby  amended by
deleting  such  Section  in  its  entirety  and  inserting  in  lieu thereof the
following new Section 9.07(a):

                 "(a)   Holding  will  not,  and  will  not  permit  any  of its
         Subsidiaries to, make any Capital Expenditures,  except that during any
         fiscal year of Holding set forth below (taken as one accounting period)
         the Borrower and its Subsidiaries may make Capital Expenditures so long
         as  the  aggregate  amount  of  all such Capital  Expenditures does not
         exceed in any fiscal year of Holding set forth below the lesser of  (x)
         6%  of  the  Borrower's  and  its  Subsidiaries  gross  revenues  on a
         consolidated  basis for such fiscal year and  (y)  the amount set forth
         opposite  such  fiscal  year  below  (as  such  amount  may be adjusted
         pursuant to the immediately succeeding paragraph):

<TABLE>
<CAPTION>
                  Fiscal Year Ending On         Amount
                  ---------------------         ------
                  <S>                           <C>
                  December 31, 2001 .........   $ 9,000,000
                  December 31, 2002 .........   $ 9,500,000
                  December 31, 2003 .........   $10,000,000
                  December 31, 2004 .........   $10,500,000
</TABLE>
<PAGE>

                 From and after the  consummation of any  Permitted  Acquisition
         after July 1, 2001,  each of the Capital  Expenditure amounts set forth
         in the table above in this clause (a) shall be increased  by  an amount
         equal to 6% of the Acquired Revenues of the respective Acquired  Entity
         or Business acquired  in each such Permitted  Acquisition  for the most
         recently  ended  12  month  period for which financial  statements  are
         available  for such  Acquired  Entity or Business (as  certified in the
         respective officer's certificate delivered  pursuant to clause  (ix) of
         Section 8.16(a)), provided that the Capital Expenditure  amount for the
         fiscal year in which such  Permitted  Acquisition  is consummated shall
         only  be  increased  by  the  amount  set  forth above in this sentence
         multiplied  by a fraction the  numerator of which is the number of days
         remaining in such fiscal year and the denominator of which is 365."

         2.      Section 9.08  of  the  Credit  Agreement  is hereby amended  by
deleting such  Section  in  its  entirety and  by inserting  in lieu thereof the
following new Section 9.08:

                 "9.08  Consolidated  Interest  Coverage Ratio.    Holding  will
         not permit the Consolidated Interest Coverage Ratio for any Test Period
         ending on the last day of a fiscal quarter of  Holding  set forth below
         to be less than the ratio set forth opposite such fiscal quarter below:
<TABLE>
<CAPTION>

                  Fiscal Quarter Ending On                  Ratio
                  <S>                                       <C> <C>
                  June 30, 2001 .........................   2.00:1.00
                  September 30, 2001 ....................   2.00:1.00
                  December 31, 2001 .....................   2.00:1.00
                  March 31, 2002 ........................   2.00:1.00
                  June 30, 2002 .........................   2.00:1.00
                  September 30, 2002 ....................   2.10:1.00
                  December 31, 2002 .....................   2.25:1.00
                  March 31, 2003 ........................   2.25:1.00
                  June 30, 2003 .........................   2.25:1.00
                  September 30, 2003 ....................   2.25:1.00
                  December 31, 2003
                  and the last day of each fiscal quarter
                  of Holding thereafter .................   2.50:1.00."
</TABLE>

         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  set forth below to be greater than  the ratio set
         forth  opposite  such fiscal  quarter  below:

                                       2
<PAGE>

<TABLE>
<CAPTION>
                  Fiscal Quarter Ending On                                         Ratio
                  ------------------------                                         -----
                  <S>                                                              <C> <C>
                  June 30, 2001 ................................................   5.25:1.00
                  September 30, 2001 ...........................................   5.25:1.00
                  December 31, 2001 ............................................   5.00:1.00
                  March 31, 2002 ...............................................   5.00:1.00
                  June 30, 2002 ................................................   4.75:1.00
                  September 30, 2002 ...........................................   4.60:1.00
                  December 31, 2002 ............................................   4.50:1.00
                  March 31, 2003 ...............................................   4.50:1.00
                  June 30, 2003 ................................................   4.25:1.00
                  September 30, 2003 ...........................................   4.25:1.00
                  December 31, 2003 ............................................   4.00:1.00
                  March 31, 2004 ...............................................   4.00:1.00
                  June 30, 2004 ................................................   4.00:1.00
                  September 30, 2004 ...........................................   4.00:1.00
                  December 31, 2004 and the last day of
                  each fiscal quarter of Holding thereafter ....................   3.75:1.00."
</TABLE>

         4.      Section  9.11 of  the  Credit  Agreement is  hereby  amended by
deleting  such  Section  in  its entirety and by inserting in  lieu  thereof the
following new Section 9.11:


                 "9.11 Minimum Consolidated Net Worth.   Holding will not permit
the Consolidated  Net Worth on the last day of each fiscal quarter of Holding to
be less than the Minimum  Consolidated  Net Worth on the last day of each fiscal
quarter of Holding."


         5.      Notwithstanding  anything  to  the  contrary  contained  in the
Credit Agreement,  Holding,  the  Borrower and the Lenders hereby agree that the
Total  Revolving  Loan  Commitment  shall  be  permanently  reduced on the Third
Amendment Effective Date  (as defined below) to  $22,500,000 (as such amount may
be further  reduced from time to time in accordance with the terms of the Credit
Agreement).  The reduction to the  Total  Revolving  Loan Commitment pursuant to
this  Section  4  shall be applied to permanently and proportionately reduce the
Revolving Loan Commitment of each Lender.


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 Third
Amendment Effective Date and as of July 23,2001 (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

                                       3
<PAGE>

earlier date) and  (ii) there exists no Default or Event of Default on the Third
Amendment  Effective  Date and  as of July 23, 2001,  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.

         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, 2001 (the
"Third Amendment Effective Date")  provided that on or before July 23, 2001 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 July 18,  2001) an amendment fee equal to 0.25% of the sum of each such
Lender's  Revolving  Loan  Commitment and  outstanding Term Loans as of July 23,
2001  (after giving effect to the Third  Amendment  Effective Date),  which  fee
shall be payable on July 23, 2001.

         7.      From  and  after  the  Third  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.

                                      * * *
                                       4
<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/ Pelham H. A. Smith
                                       -------------------------
                                          Name:  Pelham H. A. Smith
                                          Title: Chief Financial Officer




                                       HYDROCHEM INDUSTRIAL SERVICES, INC.



                                       By:/s/ Pelham H. A. Smith
                                       -------------------------
                                          Name:  Pelham H. A. Smith
                                          Title: Chief Financial Officer



<PAGE>

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



                                       By:/s/ Yousuf Omar
                                       ------------------
                                          Name:  Yousuf Omar
                                          Title: Managing Director



<PAGE>

                                       GUARANTY BANK



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



<PAGE>

                                       NATIONAL CITY BANK OF KENTUCKY



                                       By:/s/ Stephen Bassett
                                       ----------------------
                                          Name:  Stephen Bassett
                                          Title: Account Officer



<PAGE>

                                       NATEXIS BANQUES POPULAIRES



                                       By:/s/ Donovan C. Broussard
                                       ---------------------------
                                          Name:  Donovan C. Broussard
                                          Title: 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/ Carmen Dunmire
                                       ---------------------
                                          Name:  Carmen Dunmire
                                          Title: Vice President






<PAGE>

                                       WELLS FARGO BANK (TEXAS), NATIONAL
                                         ASSOCIATION



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