<PAGE>   1

                                                                   EXHIBIT 10.42


                     AMENDED AND RESTATED CREDIT AGREEMENT


     AMENDED AND RESTATED CREDIT AGREEMENT dated as of February 28, 1999,
amending the Credit Agreement dated as of August 26, 1997, as amended by
Amendment No. 1 dated as of September 30, 1997, Waiver and Amendment No. 2
dated as of May 12, 1998 and Consent and Amendment No. 3 dated as of
October 23, 1998 (the "CREDIT AGREEMENT"), among LAROCHE INDUSTRIES, INC. (the
"BORROWER"), the LENDERS party thereto (the "LENDERS") and THE CHASE MANHATTAN
BANK, as Administrative Agent (the "ADMINISTRATIVE AGENT").



                             W I T N E S S E T H :


     WHEREAS, the parties hereto desire to amend the Credit Agreement to
increase pricing, permit the sale of certain assets, prohibit the payment of
any cash dividends, decrease the level of permitted capital expenditures,
eliminate the net worth and modify the leverage and interest coverage financial
covenants, and make certain related changes, all as more fully set forth below,
and to restate the Credit Agreement in its entirety to read as set forth in the
Credit Agreement with the amendments specified below;

     NOW, THEREFORE, the parties hereto agree as follows:

     SECTION 1. Defined Terms, References. Unless otherwise specifically
defined herein, each term used herein which is defined in the Credit Agreement
has the meaning assigned to such term in the Credit Agreement. Each reference
to "hereof", "hereunder", "herein" and "hereby" and each other similar
reference and each reference to "this Agreement" and each other similar
reference contained in the Credit Agreement shall, from and after the date
hereof, refer to the Credit Agreement as amended and restated hereby.

     SECTION 2. Section 1.01. Section 1.01 of the Credit Agreement is amended by

          (a)  amending the definitions of

               (i)  "ADJUSTED BORROWER EBITDA" in its entirety to read as
          follows:
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         "ADJUSTED BORROWER EBITDA" means, (i) for any period ended on or prior
to the Term Drawdown Date or after the date on which JVC becomes a Subsidiary,
Borrower Consolidated EBITDA for such period (as restated to include, without
duplication. JVC Consolidated EBITDA for such period) and (ii) for any period
ended after the Term Drawdown Date and prior to the date on which JVC becomes a
Subsidiary, the sum of (1) Borrower Consolidated EBITDA for such period plus
(2) Adjusted JVC EBITDA for such period.

         (ii)   "APPLICABLE RATE" by replacing, in the last line of the chart
set forth therein, ".75%" with "1.75%", "2.00%" with "3.00%" and "1.75%" with
"2.75%".

         (iii)  "LEVERAGE RATIO" so that the last sentence thereof reads in its
entirety as follows:

For purposes of determining Borrower Consolidated EBITDA for purpose of
determining Adjusted Borrower EBITDA at any time during the fiscal quarter in
which a Permitted Acquisition or a disposition which has a material effect on
future Borrower Consolidated EBITDA has been made and the three fiscal quarters
immediately succeeding such fiscal quarter, Borrower Consolidated EBITDA shall
be increased or decreased, as appropriate, for any fiscal quarter which began
prior to such Permitted Acquisition or disposition by the amount of Borrower
Consolidated EBITDA which the Borrower shall determine would have been
attributable to the acquired or disposed of assets for the fiscal quarter most
recently ended on or prior to the date of such Permitted Acquisition or
disposition, provided that (i) the Administrative Agent shall have consented to
the calculation on the basis of which the Borrower determined such amount to be
so attributed and (ii) for the fiscal quarter in which the Permitted
Acquisition or disposition has occurred, such increase or decrease shall be
prorated to reflect only the days during such fiscal quarter prior to the
consummation of the Permitted Acquisition or disposition.

         (iv) "PERMITTED ACQUISITION" by inserting after the words "provided
that" and before clause (w) the following new clause (v):

         (iv)  if, after giving effect to such acquisition, the amount of
Indebtedness of the Borrower and its Subsidiaries shall have increased, the
Required Lenders shall have consented to such acquisition in their sole
discretion;

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     (b)  inserting therein, in proper alphabetical order, the following defined
terms:

          "AMENDMENT 4 EFFECTIVE DATE" means the date on which the Amended and
     Restated Credit Agreement dated as of February 28, 1999, amending this
     Agreement, became effective.

          "AVAILABLE AMOUNT" means, (i) prior to the earlier of July 15, 1999 or
     the date on which the purchase of the capital stock of JVC pursuant to the
     Put/Call Arrangements is consummated, $80,000,000 (the earlier of such
     dates, the "TRIGGER DATE"), and (ii) on or after the Trigger Date, the
     Borrowing Base.

          "BORROWING BASE" means, at any date, the amount of the Borrowing Base
     as of the date of the Borrowing Base Certificate then most recently
     delivered by the Borrower pursuant to Section 5.01(1) (the "BORROWING BASE
     DATE"), determined by calculating the sum of (i) 85% of the aggregate
     amount of Eligible Receivables at the Borrowing Base Date plus (ii) 50% of
     the aggregate amount of Eligible Inventory at the Borrowing Base Date plus
     (iii) the Facilities Domestic Amount at the Borrowing Base Date plus (iv)
     the Facilities Foreign Amount at the Borrowing Base Date.

          "BORROWING BASE CERTIFICATE" means a certificate, duly executed by a
     Financial Officer, appropriately completed and in substantially the form of
     Exhibit J hereto.

          "ELIGIBLE INVENTORY" means, at any date, the value (determined at the
     lower of cost or market on a first-in, first-out basis) of all Inventory
     owned by (and in the possession or under the control of) the Borrower or
     any Subsidiary Guarantor and located in a jurisdiction in the United Stated
     of America, as to which appropriate Uniform Commercial Code file search
     reports have been received and appropriate Uniform Commercial Code
     financing statements have been filed naming the Borrower or such Subsidiary
     Guarantor as "DEBTOR" and the Administrative Agent as "SECURED PARTY" and
     in which the Administrative Agent has a first priority perfected security
     interest and as to which all representations and warranties in the
     applicable Security Agreement are true and correct (excluding, however, any
     such Inventory which is covered by a negotiable document of title or is in
     transit or has been shipped to a customer, even if on a consignment or
     "SALE OR RETURN" basis, unless the Required Lenders (in their reasonable
     judgment) notify the Borrower in writing that any such Inventory may be
     included in Eligible Inventory); provided that the



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Required Lenders (through the Administrative Agent) may at any time exclude from
Eligible Inventory any type of Inventory which the Required Lenders (in their
reasonable judgment) determine to be unmarketable.

     "ELIGIBLE RECEIVABLES" means, at any date, the aggregate of all Receivables
at said date due to the Borrower and the Subsidiary Guarantors other than the
following (determined without duplication):

     (a) all Receivables which, at the date of issuance of the respective
invoice therefor, were payable more than sixty days after such invoice,

     (b) any Receivable due from an account debtor whose principal place of
business is located outside of the United States of America unless (i) such
Receivable is backed by U.S. Government insurance (in form and substance
satisfactory to the Administrative Agent) or a letter of credit (in form and
substance satisfactory to the Administrative Agent) issued or confirmed by a
bank organized under the laws of the United States of America or a State thereof
and having capital and surplus in excess of $500,000,000 (so long as such
insurance or such letter of credit has been delivered to the Administrative
Agent as additional collateral under the Security Documents) or (ii) such
account debtor has previously been approved in writing by the Required Lenders
as an eligible foreign account debtor for purposes of this Agreement,

     (c) any Receivable due from an account debtor which the Required Lenders
(through the Administrative Agent) have notified the Borrower does not have a
satisfactory credit standing (as determined in the reasonable judgment of the
Required Lenders),

     (d) any Receivable which remains unpaid for more than ninety days measured
from the date of the original issuance of the invoice therefor,

     (e) any Receivables which arise from the delivery of Inventory on a
bill-and-hold, sale-or-return or guaranteed sale terms basis,

     (f) all Receivables due from any account debtor if more than 15% of the
aggregate amount of the Receivables of such account debtor (exclusive of
Receivables described in clause (f) below) have at the time remained unpaid for
more than ninety days (measured from the date of the original issuance of the
invoice therefor),


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     (g) any Receivable as to which there is any unresolved dispute with or
offset or counterclaim by the respective account debtor (but only to the extent
of such dispute, offset or counterclaim),

     (h) any Receivable evidenced by an instrument or chattel paper (as defined
in Article 9 of the Uniform Commercial Code) not in the possession of the
Administrative Agent, or which has been reduced to a judgment,

     (i) if the Receivables due from any account debtor exceed an amount equal
to 20% of the aggregate of all Receivables at said date, an amount of such
Receivables equal to such excess, and

     (j) any Receivable with respect to which the Administrative Agent does not
have a first priority perfected security interest or any of the representations
or warranties in the applicable Security Agreement is untrue or incorrect.

     "FACILITIES DOMESTIC AMOUNT" means, at any date, an amount equal to (i) 80%
of the sum of the Facility Amounts at such date with respect to the Facilities
located in a jurisdiction in the United States of America minus (ii) the
aggregate principal amount of Term Loans outstanding on the Amendment 4
Effective Date; provided that the "Facilities Domestic Amount" shall not exceed
$60,000,000. It is understood that the Facilities Domestic Amount" shall not be
reduced by any exposure of the Borrower or any Subsidiary under Hedging
Agreements.

     "FACILITIES FOREIGN AMOUNT" means, at any date, an amount equal to (i) 80%
of the sum of the Facility Amounts at such date with respect to the Facilities
located in a jurisdiction outside the United States of America, to the extent
such Facilities are subject to the Lien of the Collateral Documents (unless the
Required Lenders otherwise agree), minus (ii) the aggregate principal or face
amount of Indebtedness outstanding on such date of each Foreign Subsidiary that
owns any Facility the Facility Amount with respect to which is included in
clause (i) of this definition (other than Indebtedness permitted by Section
6.01(iv)); provided that the "Facilities Foreign Amount" shall not exceed
$15,000,000. It is understood that the Facilities Foreign Amount shall not be
reduced by any exposure of the Borrower or any Subsidiary under Hedging
Agreements.

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         "FACILITY" means (i) any real property owned and used by the Borrower
or any of its Subsidiaries at Cherokee, Alabama, Seneca, Illinois, Crystal
City, Missouri, Geneva, Utah (and, to the extent such real property is owned
and used by the IPG Distribution Group, elsewhere in the United States of
America), Hoechst, Germany and (from and after the date JVC becomes a
Subsidiary) Pont-de-Claix, France (ii) all buildings, fixtures, machinery and
equipment owned by such Person and located thereon and (iii) all machinery and
equipment owned by the IPG Distribution Group which is located on real property
in the United States of America leased to the IPG Distribution Group.

         "FACILITY AMOUNT" means at any date, with respect to any Facility,
the orderly liquidation value thereof, as set forth in the appraisal with
respect to such Facility delivered by the Borrower pursuant to Section 5.01(m)
and approved by the Required Lenders in their sole judgment. The Lenders shall
use their good faith efforts to review any such appraisal, and to advise the
Borrower whether such appraisal has been approved by them, within five Business
Days of receipt thereof.

         "INVENTORY" means inventory (as defined in Article 9 of the Uniform
Commercial Code) to the extent comprised of readily marketable materials,
products or goods of a type manufactured or consumed by the Borrower or any
Subsidiary Guarantor in the ordinary course of business as presently conducted
(but excluding work-in-process which is not readily marketable in its current
form).

         "RECEIVABLES" means, as at any date, the unpaid portion of the
obligation, payable in U.S. Dollars as stated on the respective invoice, of a
customer (other than an Affiliate of the Borrower or the U.S. government or any
political subdivision or any agency thereof) of the Borrower or any Subsidiary
Guarantor in respect of Inventory purchased and shipped, net of any credits,
rebates or offsets owed to the respective customer and also, if the Required
Lenders (in their reasonable judgment) shall so specify by notice to the
Borrower (through the Administrative Agent), net of any commissions payable to
third parties.

         "SENIOR LEVERAGE RATIO" means, at the last day of any fiscal quarter,
the ratio of (i) Consolidated Senior Indebtedness on such day (other than such
Indebtedness consisting of contingent obligations with respect to letters of
credit and letters of guarantee) to (ii) Adjusted Borrower EBITDA for the
period of our consecutive fiscal quarters ended on such day. For purposes of
this definition, "CONSOLIDATED SENIOR INDEBTEDNESS" means Consolidated
Indebtedness other than the Senior

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         Subordinated Notes and any other Indebtedness which by its terms is
         subordinated in right of payment to Indebtedness created under this
         Agreement on written terms acceptable to the Administrative Agent. For
         purposes of determining Borrower Consolidated EBITDA for purposes of
         determining Adjusted Borrower EBITDA at any time during the fiscal
         quarter in which a Permitted Acquisition has been made and the three
         fiscal quarters immediately succeeding such fiscal quarter, Borrower
         Consolidated EBITDA shall be increased for any fiscal quarter which
         began prior to such Permitted Acquisition by the amount of Borrower
         Consolidated EBITDA which the Borrower shall determine would have been
         attributable to the acquired assets for the fiscal quarter most
         recently ended on or prior to the date of such Permitted Acquisition;
         provided that (i) the Administrative Agent shall have consented to the
         calculation on the basis of which the Borrower determined such amount
         to be so attributed and (ii) for the fiscal quarter in which the
         Permitted Acquisition has occurred, such increase shall be prorated to
         reflect only the days during such fiscal quarter prior to the
         consummation of the Permitted Acquisition.

         (c) deleting the definition of "CONSOLIDATED NET WORTH".

         Section 3. Section 2.01(b). The first sentence of Section 2.01(b) of
the Credit Agreement is amended in its entirety to read as follows:

         Subject to the terms and conditions set forth herein, each Lender
         agrees to make loans to the Borrower from time to time during the
         Availability Period in an aggregate Dollar Amount that will not result
         in (i) such Lender's Revolving Credit Exposure exceeding such Lender's
         Revolving Commitment or (ii) the aggregate Revolving Credit Exposures
         exceeding the Available Amount.

         Section 4. Section 2.04(b). The numbered clauses at the end of the
last sentence of Section 2.04(b) of the Credit Agreement are amended in their
entirety to read as follows:

(i) the LC Exposure shall not exceed the least of (x) $30,000,000, (y) the
total Revolving Commitments at such time and (z) the Available Amount at such
time, and (ii) no more than twenty Letters of Credit shall be outstanding.

         Section 5. Section 2.09(b). (a) Section 2.09(b)(i) of the Credit
Agreement is amended to add after the words "Schedule 2.09" in the second
proviso to subclause (x) the words "and Asset Sales specified in clause (iv) of
Section 6.03(c), other than the first $15,000,000 of Net Cash Proceeds from the
sale of the Alumina Chemicals business unit,"


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<PAGE>   8
     (b) Section 2.09(b)(ii) of the Credit Agreement is amended to add before
the period at the end of the second paragraph thereof the following proviso:

     ; and provided further that the first $15,000,000 of Net Cash Proceeds from
     the sale of the Alumina Chemicals business unit shall be applied to reduce
     Revolving Commitments.

     (c) The first sentence of Section 2.09(b)(iii) of the Credit Agreement is
amended in its entirety to read as follows:

         (iii) If on the date of any reduction of the Revolving Commitments
     pursuant to clauses (i) or (ii) of this paragraph the aggregate Revolving
     Credit Exposure on such date exceeds the aggregate Revolving Commitments on
     such date as then reduced or the Available Amount (or if the Revolving
     Commitments have terminated but there is still Revolving Credit Exposure),
     the Borrower shall apply an amount equal to such excess to prepay the
     Revolving Loans and cash collateralize Letters of Credit so that after
     giving effect thereto the Revolving Credit Exposure of each Lender does not
     exceed its Revolving Commitment as then reduced or its pro rata share of
     the Available Amount (or until there is no Revolving Credit Exposure).

     SECTION 6. Section 4.03. Section 4.03 of the Credit Agreement is amended to
add the following new clause (e) at the end thereof:

     (e) Immediately after giving effect to such Borrowing or such issuance,
amendment, renewal or extension, as the case may be, the aggregate Revolving
Credit Exposures do not exceed the Available Amount at such date.

     SECTION 7. Section 5.01. Section 5.01 of the Credit Agreement is amended to
delete the word "and" at the end of clause (k), reletter clause (l) as clause
(n), and insert in the proper alphabetical order the following clauses (l) and
(m):

         (l)(x) on the date the Available Amount first equals the Borrowing
     Base, and (y) as soon as available and in any event within (i) ten Business
     Days after the last day of each calendar month, and (ii) five Business Days
     after receipt of a request therefor (which may be given from time to time
     after the occurrence and during the continuation of a Default) from the
     Required Lenders, a Borrowing Base Certificate as at such day or the date
     of such request, as the case may be; provided that, in the case of any
     Borrowing Base Certificate to be delivered pursuant to the foregoing clause
     (ii), Eligible Inventory shall be calculated based on the amount of


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     Eligible Inventory as of the date of the Borrowing Base Certificate most
     recently delivered pursuant to clause (i), adjusted to reflect the
     Company's best estimate of changes in Eligible Inventory since the date of
     such Borrowing Base Certificate;

          (m) on or prior to May 31, 1999, an appraisal of the orderly
     liquidation value of the fixed assets of the Borrower and its Subsidiaries
     conducted by Valuation Research Corporation; and

     SECTION 8. Section 5.09. Section 5.09 of the Credit Agreement is amended to
add the following clause (d) at the end thereof:

          (d) The Borrower will deliver to the Lenders, (i) in the case of JVC,
     on or before the date which is 90 days after JVC becomes a Subsidiary, and
     (ii) in the case of all other Foreign Subsidiaries, on or before June 30,
     1999, a memorandum (a "FOREIGN COLLATERAL MEMORANDUM"), prepared after
     consultation with the Administrative Agent, setting forth the stock and
     assets of Foreign Subsidiaries in which the Borrower proposes to cause to
     be granted to the Administrative Agent a security interest, taking into
     account legal issues, tax and other cost considerations and the desire of
     the Borrower and the Lenders that Foreign Subsidiaries have available to
     them Indebtedness permitted by clauses (xi) and (xii) of Section 6.01(a).
     If the Required Lenders consent in writing (and in their sole discretion)
     to the proposal set forth in a Foreign Collateral Memorandum or consent to
     an alternative proposal with respect to the relevant Foreign Subsidiaries
     (any such consent, a "CONSENT"), the Borrower shall cause the security
     interest described therein to be granted as promptly as practicable and in
     any event no later than the date which is 45 days after the effective date
     of such Consent. If the Required Lenders (in their sole discretion) have
     not given a Consent within 60 days after receipt by the Administrative
     Agent of the related Foreign Collateral Memorandum, the Required Lenders
     may by written notice to the Borrower deem the Borrower to have failed to
     perform the covenant set forth in this paragraph (d), which deemed failure
     shall constitute an Event of Default.

     SECTION 9. Section 6.01(a). Section 6.01(a)(xi) of the Credit Agreement is
amended to replace the number "$10,000,000" with the number "$15,000,000".

     SECTION 10. Section 6.03(c). Section 6.03(c) of the Credit Agreement is
amended by replacing the words "and" preceding the designation "(iii)" with a
comma and inserting before the period at the end of clause (iii) the following:


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<PAGE>   10

     , and (iv) the sale of Borrower's interest in Kaiser LaRoche Hydrate
     Partnership and the Alumina Chemicals business unit, provided that the
     sale of the Alumina Chemicals business unit is consummated on or prior
     to the date, and for the consideration, specified by the Borrower to the
     Lenders in writing on March 17, 1999.

     SECTION 11. Section 6.06(a)(ii). (a) Section 6.06(a)(ii) of the Credit
Agreement is amended by adding prior to the comma at the end thereof the
following:

     ; provided that the Required Lenders shall have consented to such
     declaration and payment in their sole discretion

     (b)  Section 6.06(a)(v) of the Credit Agreement is amended to replace the
words "during the term of this Agreement does not exceed $3,500,000" with the
following:

          after February 28, 1999 does not exceed $500,000

     SECTION 12. Section 6.11. The chart set forth in Section 6.11 of the
Credit Agreement is amended in its entirety to read as follows:


                    Fiscal Year           Amount
                    -----------           ------

                      1998              $75,000,000
                      1999               55,000,000
                      2000               25,000,000
                      2001               25,000,000
                      2002               25,000,000
                      2003               25,000,000
                      Thereafter         25,000,000;

provided that for any fiscal year during which JVC is a subsidiary, the amount
set forth opposite such year shall be $30,000,000 instead of $25,000,000.

     SECTION 13. Section 6.12. The chart set forth in Section 6.12 of the
Credit Agreement is amended in its entirety to read as follows:



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               Period                   Ratio
               ------                   -----
               3/01/99 - 5/31/99        12.50:1
               6/01/99 - 8/31/99         9.50:1
               9/01/99 - 11/30/99        9.25:1
               12/01/99 - 2/28/00        3.00:1
               3/01/00 - 5/31/01         4.00:1
               6/01/01 - 5/31/02         3.50:1
               Thereafter                3.25:1

     SECTION 14. Section 6.13. Section 6.13 of the Credit Agreement is amended
in its entirety to read as follows:

         SECTION 6.13. Senior Leverage Ratio. At the last day of any fiscal
     quarter of the Borrower in any period (both dates inclusive) set forth
     below, the Senior Leverage Ratio will not exceed the ratio set forth below
     opposite such period.

               Period                   Ratio
               ------                   -----
               3/01/99 - 5/31/99        4.00:1
               6/01/99 - 11/30/99       3.75:1
               12/01/99 - 2/28/00       3.50:1
               Thereafter               3.00:1

     SECTION 15. Section 6.14. Section 6.14 of the Credit Agreement is amended
in its entirety to read as follows:

         SECTION 6.14. Interest Coverage Ratio. At the last day of any fiscal
     quarter of the Borrower in any period (both dates inclusive) set forth
     below, the Interest Coverage Ratio will not be less than the ratio set
     forth below opposite such period.

               Period                   Ratio
               ------                   -----
               3/01/99 - 5/31/99        0.40:1
               6/01/99 - 8/31/99        0.20:1
               9/01/99 - 11/30/99       0.55:1
               12/01/99 - 2/28/00       1.00:1
               3/01/00 - 5/31/01        2.50:1
               Thereafter               2.75:1


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<PAGE>   12

         SECTION 16. Article VII. Clause (d) of Article VII is amended to
replace the expression "or 5.08" with the expression ",5.08 or 5.09(d)".

         SECTION 17. Exhibit J. A new Exhibit J is added to the Credit
Agreement, to read in its entirety as set forth on Exhibit J hereto.

         SECTION 18. Representations of Borrower. The Borrower represents and
warrants that after giving effect to the foregoing provisions of this Amended
and Restated Credit Agreement (i) the representations and warranties of the
Borrower set forth in Article 3 of the Credit Agreement will be true and
correct on and as of the Effective Date (as hereinafter defined) to the same
extent as they would be required to be under Section 4.03(b) on the occasion of
any Borrowing and (ii) no Default will have occurred and be continuing on such
date.

         SECTION 19. Governing Law. This Amended and Restated Credit Agreement
shall be governed by and construed in accordance with the laws of the State of
New York.

         SECTION 20. Counterparts. This Amended and Restated Credit Agreement
may be signed in any number of counterparts, each of which shall be an
original, with the same effect as if the signatures thereto and hereto were
upon the same instrument.

         SECTION 21. Effectiveness. This Amended and Restated Credit Agreement
shall become effective, and the Credit Agreement shall have been restated to
read as set forth in the Credit Agreement with the amendments specified herein,
as of the date hereof on the date (the "EFFECTIVE DATE") when the
Administrative Agent shall have received (i) from the Borrower, for the account
of each Lender which has signed a counterpart hereof on or prior to April 16,
1999, an amendment fee equal to 0.25% of such Lender's aggregate Revolving
Credit Exposure and Term Loans on such date, and (ii) from each of the Borrower
and the Required Lenders a counterpart hereof signed by such party or facsimile
or other written confirmation (in form satisfactory to the Administrative
Agent) that such party has signed a counterpart hereof.


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<PAGE>   13
     IN WITNESS WHEREOF, the parties hereto have caused this Amended and
Restated Credit Agreement to be duly executed as of the date first above
written.

                                   LAROCHE INDUSTRIES INC.

                                   By: _________________________________________
                                       Name:
                                       Title:


                                   THE CHASE MANHATTAN BANK

                                   By: _________________________________________
                                       Name:
                                       Title:


                                   HIBERNIA NATIONAL BANK

                                   By: _________________________________________
                                       Name:
                                       Title:


                                   WACHOVIA BANK, N.A.

                                   By: _________________________________________
                                       Name:
                                       Title:


                                       13
<PAGE>   14
                                   THE BANK OF NOVA SCOTIA

                                   By: _________________________________________
                                       Name:
                                       Title:


                                   By: _________________________________________
                                       Name:
                                       Title:


                                   PNC BANK, NATIONAL ASSOCIATION

                                   By: _________________________________________
                                       Name:
                                       Title:


                                   AMSOUTH BANK

                                   By: _________________________________________
                                       Name:
                                       Title:


                                   BHF-BANK AKTIENGESELLSCHAFT

                                   By: _________________________________________
                                       Name:
                                       Title:

                                   By: _________________________________________
                                       Name:
                                       Title:


                                       14
<PAGE>   15
                                   COMERICA BANK

                                   By: _________________________________________
                                       Name:
                                       Title:


                                   NATIONAL BANK OF CANADA

                                   By: _________________________________________
                                       Name:
                                       Title:

                                   By: _________________________________________
                                       Name:
                                       Title:


                                   PARIBAS

                                   By: _________________________________________
                                       Name:
                                       Title:

                                   By: _________________________________________
                                       Name:
                                       Title:


                                       15
<PAGE>   16
                                                                       EXHIBIT J

                      [Form of Borrowing Base Certificate]

                           BORROWING BASE CERTIFICATE

         Reference is made to the Amended and Restated Credit Agreement dated
as of February 28, 1999, amending the Credit Agreement dated as of August 26,
1997, as amended by Amendment No. 1 dated as of September 30, 1997, Waiver and
Amendment No. 2 dated as of May 12, 1998 and Consent and Amendment No. 3 dated
as of October 23, 1998 (as modified and supplemented and in effect from time to
time, the "CREDIT AGREEMENT") among LaRoche Industries Inc. (the "COMPANY"),
the lenders party thereto named therein, and The Chase Manhattan Bank, as
administrative agent for said lenders. Terms defined in the Credit Agreement
are used herein as defined therein.

         Pursuant to Section 5.01(1) of the Credit Agreement, the undersigned,
a Financial Officer of the Company, hereby certifies that, to the best of
[his/her] knowledge, attached hereto as Annex 1 is a true and accurate
calculation of the Borrowing Base as at the [monthly/weekly] accounting period
ended __________________, ____ determined in accordance with the requirements
of the Credit Agreement.

         IN WITNESS WHEREOF, the undersigned has caused this certificate to be
duly executed as of the ___ day of _________, ____.




                                             ----------------------------------
                                             Name:

                                             Title:
<PAGE>   17
                                                                         ANNEX 1


                           Borrowing Base Certificate

                            LaRoche Industries Inc.
                           Borrowing Base Certificate
                                Omitted (000's)

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Gross Receivables - beginning balance
  period ended ______________, __________                   _____________

Rebates, credits and offsets                                _____________

Receivables from Affiliates                                 _____________

Governmental Receivables                                    _____________

Net Receivables - beginning balance
  period ended ______________, __________                   _____________

Plus: total sales for period                                _____________

Less: total cash receipts for period                        _____________

    total credits for period (returns and
    allowances)                                             _____________

    total increase (decrease) in offsets for
    period                                                  _____________

    total other adjustments for period (+/-)
    (details attached) including rebates
    and credits                                             _____________

Net Receivables - ending balance
  period ended ______________, ___________                  _____________

Less: ineligible Receivables at period end
      (determined pursuant to definition of
      Eligible Receivables in Credit
      Agreement, without duplication):


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<PAGE>   18

Receivables over 60 days original
terms                                                 __________

Export Receivables without acceptable
letters of credit or US Govt insurance
delivered to the Administrative Agent as
collateral and not otherwise approved by
Required Lenders                                      __________

Receivables from debtors with
unsatisfactory credit standing (as
determined by Required Lenders)                       __________

Receivables remaining unpaid over 90
days from invoice date                                __________

Receivables arising from delivery of
Inventory on bill-and-hold, sale-or-return or
guaranteed sale basis                                 __________

Receivables from debtors with excess of
15% of balances past 90 days from invoice
date (exclusive of Receivables subject to
dispute)                                              __________

Receivables subject to dispute, offset or
counterclaim                                          __________

Receivables evidenced by instruments
or chattel paper not in the possession of
Administrative Agent or which has been
reduced to a judgment                                 __________

Receivables from any debtor to extent they
exceed 20% of aggregate of all Receivables            __________

Receivables as to which Administrative
Agent does not have first priority perfected
security interest or representations and
warranties are untrue or incorrect                    __________

Total ineligible Receivables                          __________

Total Eligible Receivables                            __________

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<PAGE>   19
Inventory at lower of cost or market (using
first-in-first-out-basis) owned by the
Company, located in United States, and
covered by appropriate filings (from
attached schedule):

Beginning period Inventory balance
____________, ______                                       _____________

Ending period Inventory balance
____________, ______                                       _____________

Less:  ineligible Inventory at period end
       (determined pursuant to definition
       of Eligible Inventory in Credit
       Agreement):

Inventory not located in U.S.                              _____________

Inventory as to which Administrative Agent
does not have first priority perfected
security interest or representation and
warranties are untrue                                      _____________

Inventory covered by negotiable document
of title                                                   _____________

Inventory in transit or shipped to customers               _____________

Inventory determined to be unmarketable                    _____________

Total Eligible Inventory                                   _____________

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Facilities in U.S.:

     Cherokee, Alabama                                     _____________

     Seneca, Illinois                                      _____________

     Crystal City, Missouri                                _____________

     Geneva, Utah                                          _____________

     other IPG sites                                       _____________

80% of sum of Facility Amounts                             _____________


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<PAGE>   20
Less: Ending period Term Loans Balance                ________

Subtotal

Facilities Domestic Amount:

Lesser of Subtotal and $60 million                    ________

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Facilities outside U.S.:

     Hoechst, Germany                                  ________

     Pont-de-Claix, France (if JVC is a
     Subsidiary)                                       ________

80% of sum of Facility Amounts                         ________

Less:  Ending period Indebtedness of
       relevant Foreign Subsidiaries                   ________

Subtotal                                               ________

Facilities Foreign Amount:                             ________

Lesser of Subtotal and $20 million                     ________

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Borrowing Base:

85% of Eligible Receivables                            ________

Plus: 50% of Eligible Inventory

Plus: Facilities Domestic Amount                       ________

Plus: Facilities Foreign Amount                        ________

Borrowing Base:                                        ________

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Revolving Loans Balance
Period begin ___________, ____                         ________

advances for period                                    ________

reductions for period                                  ________

other adjustments (+/-)                                ________


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<PAGE>   21

Revolving Loans Balance
Period end __________, ____                           __________

Total outstandings                                    __________

Availability (overadvance)                            __________

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<PAGE>   22
                               Inventory Schedule

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                                                      Unit
                                                      Cost
                                       Quantity       Cents/    Value   Eligible
                                       M Units        Unit      M$         M$
                                       --------       ------    -----   --------

Finished Product
Inventory
----------------

Location/product/unit

Total fin. prod. inv

Raw Material Inventory
----------------------

Location/product/unit

Total raw materials inv.

Inventory Value - M$
--------------------

Finished product inventory

Raw materials inventory

All inventory set forth above was produced in compliance with the requirements
of the Fair Labor Standards Act, as amended.

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