SECOND AMENDMENT TO CREDIT AGREEMENT

          SECOND AMENDMENT TO CREDIT AGREEMENT (this  "Amendment"),  dated as of
August 8, 2003 among AEARO  CORPORATION,  a Delaware  corporation  ("Holdings"),
AEARO  COMPANY I, a  Delaware  corporation  (the "US  Borrower"),  AEARO  CANADA
LIMITED,  an Ontario  corporation (the "Canadian  Borrower"),  AEARO LIMITED,  a
limited  liability company formed under the laws of England (the "UK Borrower"),
each of the Subsidiary  Guarantors (as defined in the Credit Agreement  referred
to  below),  each of the  undersigned  banks and  DEUTSCHE  BANK  TRUST  COMPANY
AMERICAS (as successor to Bankers Trust Company),  as Administrative  Agent (the
"Administrative Agent"). Unless otherwise defined herein, capitalized terms used
herein and defined in the Credit Agreement  referred to below are used herein as
so defined.

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


          WHEREAS,  Holdings,  the US Borrower,  the Canadian  Borrower,  the UK
Borrower,  the Banks  from time to time  party  thereto  and the  Administrative
Agent,  are party to a Credit  Agreement,  dated as of July 11, 1995 and amended
and  restated  as of July 13,  2001 (as the same has been  amended,  modified or
supplemented to, but not including, the date hereof, the "Credit Agreement");

          WHEREAS,  subject to the terms and  conditions  set forth  below,  the
parties hereto wish to amend the Credit Agreement as provided herein;

NOW, THEREFORE, it is agreed;

A. Amendments

1. The Credit  Agreement is hereby  amended by (a) deleting  all  references  to
"Bankers Trust Company" contained in the Credit Agreement and inserting the text
"Deutsche  Bank Trust  Company  Americas"  in lieu  thereof and (b) after giving
effect to the  amendment  made in clause (a) above,  deleting all  references to
"BTCo"  contained in the Credit Agreement and inserting the text "DBTCA" in lieu
thereof.  2.  Section  4.02(d)  of the  Credit  Agreement  is hereby  amended by
inserting the text "or the Second Amendment  Effective Date"  immediately  after
the text "as in effect on the Restatement  Effective Date" appearing therein. 3.
Section 6.10(a) of the Credit Agreement is hereby amended by deleting the amount
"$5,000,000"  appearing  therein and inserting the new amount  "$10,000,000"  in
lieu thereof.  4. Section 8.03 of the Credit  Agreement is hereby amended by (a)
deleting the word "and" immediately  following clause (ix) thereof, (b) deleting
the period  appearing at the end of clause (x) thereof and inserting a semicolon
in lieu thereof and (c) inserting  the  following  new clauses  (xi),  (xii) and
(xiii) immediately following clause (x) thereof:

          "(xi) the US Borrower may pay a one time cash  Dividend to Holdings in
an aggregate amount not to exceed $35,000,000, provided that such Dividend shall
be promptly used by Holdings solely to effect the Cabot Equity Repurchase and to
pay reasonable fees and expenses in connection therewith;

          (xii) the Cabot Equity Repurchase shall be permitted; and

          (xiii) the US  Borrower  may pay cash  Dividends  to  Holdings  in the
amounts and at the times of any  payment by Holdings of interest  when due under
the  Holdings  Senior  Subordinated  Note or under any Holdings  Note  Permitted
Refinancing Indebtedness,  as the case may be, provided that such Dividend shall
be promptly  used by  Holdings  solely to pay such  interest  when due under the
Holdings  Senior  Subordinated  Note or any Holdings Note Permitted  Refinancing
Indebtedness,  as the case may be." 5. Section  8.04 of the Credit  Agreement is
hereby amended by (a) deleting the word "and" immediately  following clause (xv)
thereof,  (b) deleting the period  appearing at the end of clause (xvi)  thereof
and  inserting a semicolon in lieu thereof and (c)  inserting  the following new
clauses (xvii) and (xviii) immediately following clause (xvi) thereof:

          "(xvii)   Indebtedness   of  Holdings   under  the   Holdings   Senior
Subordinated  Note shall be permitted,  provided that all proceeds thereof shall
be promptly used by Holdings solely to effect the Cabot Equity Repurchase and to
pay reasonable fees and expenses in connection therewith; and

          (xviii)  Holdings Note Permitted  Refinancing  Indebtedness so long as
(x) no Default or Event of Default then exists or would result therefrom and (y)
the  proceeds  thereof are used,  to promptly  repurchase,  redeem or  otherwise
retire the then outstanding principal amount of the Holdings Senior Subordinated
Note." 6. Section 8.05 of the Credit Agreement is hereby amended by (a) deleting
the word "and"  immediately  following  clause (xvii) thereof,  (b) deleting the
period  appearing at the end of clause (xviii) thereof and inserting the text ";
and"  in  lieu  thereof  and  (c)  inserting  the  following  new  clause  (xix)
immediately following clause (xviii) thereof:

          "(xix) the Cabot Equity  Repurchase  shall be  permitted."  7. Section
8.06 of the Credit  Agreement  is hereby  amended by (a) deleting the word "and"
immediately  following clause (v) thereof,  (b) deleting the period appearing at
the end of clause (vi)  thereof and  inserting  the text "; and" in lieu thereof
and (c) inserting the following new clause (vii)  immediately  following  clause
(vi) thereof:

          "(vii) the Cabot Equity  Repurchase  shall be  permitted."  8. Section
8.08 of the Credit  Agreement is hereby amended by deleting  Section 8.08 in its
entirety and inserting the following new Section 8.08 in lieu thereof:

          "8.08 Leverage  Ratio.  Holdings and the Borrowers will not permit the
Leverage  Ratio as of the last day of any Test Period  ending on the last day of
any fiscal  quarter  ending on a date set forth  below to be more than the ratio
set forth opposite such date below:

Date                                                             Ratio
September 30, 2001                                               4.50:1.00
December 31, 2001                                                4.50:1.00
March 31, 2002                                                   4.50:1.00
June 30, 2002                                                    4.50:1.00
September 30, 2002                                               4.50:1.00
December 31, 2002                                                4.25:1.00
March 31, 2003                                                   4.25:1.00
June 30, 2003                                                    4.00:1.00
September 30, 2003                                               4.00:1.00
December 31, 2003                                                4.00:1.00
March 31, 2004                                                   4.00:1.00
June 30, 2004                                                    4.00:1.00
September 30, 2004                                               3.75:1.00
December 31, 2004                                                3.75:1.00
March 31, 2005                                                   3.50:1:00

          Notwithstanding  anything to the contrary contained in this Agreement,
all  calculations  of  compliance  with this Section 8.08 shall be made on a Pro
Forma Basis." 9. Section  8.11(i) of the Credit  Agreement is hereby  amended by
deleting Section 8.11(i) in its entirety and inserting the following new Section
8.11(i) in lieu thereof:

          "(i) make (or give any notice in respect of) any voluntary or optional
payment or  prepayment  on or  redemption  or  acquisition  for value of, or any
prepayment  or  redemption  as a result of any change of control,  asset sale or
similar event of (1) after the issuance thereof, any Permitted Seller Notes, (2)
after the issuance thereof, any of the Shareholder  Subordinated Notes except as
provided in Section 8.03(iv), (3) any of the Senior Subordinated Notes, or after
the incurrence thereof, any Permitted Refinancing Subordinated Indebtedness, (4)
any Qualified Earn-Out  Obligation or (5) the Holdings Senior Subordinated Note,
or after  the  incurrence  thereof,  any  Holdings  Note  Permitted  Refinancing
Indebtedness,  provided  that, in the case of clauses (1) through (4) above,  so
long as no Default or Event of Default then exists or would result therefrom the
US Borrower may (x) repurchase,  redeem or otherwise retire  outstanding  Senior
Subordinated  Notes with the  proceeds  of  Permitted  Refinancing  Subordinated
Indebtedness,  (y) repurchase,  redeem or otherwise  retire  outstanding  Senior
Subordinated  Notes if both before and after giving  effect to such  repurchase,
redemption  or other  retirement  (A) the  Senior  Leverage  Ratio is less  than
1.85:1.00 and (B) the Total Unutilized  Revolving Loan Commitment is equal to or
greater  than the sum of  $10,000,000  and (z) for the  period  from  the  First
Amendment  Effective Date to, and including,  the date which is 45 Business Days
after the First Amendment Effective Date, repurchase, redeem or otherwise retire
at par value or below  par value  outstanding  Senior  Subordinated  Notes in an
aggregate principal amount not to exceed  $10,000,000," so long as (A) the first
$5,000,000 of proceeds used for such repurchase, redemption or retirement of the
Senior  Subordinated  Notes is provided from cash and Cash Equivalents of the US
Borrower and (B) the  remaining  proceeds are provided  from either (I) cash and
Cash  Equivalents  of the US  Borrower  or (II) the  incurrence  of the A-1 Term
Loans; it being  understood and agreed that (C) the proceeds from the incurrence
of  Revolving  Loans  shall  not be  used  for  the  repurchase,  redemption  or
retirement of the Senior  Subordinated Notes pursuant to this clause (z) and (D)
any Senior  Subordinated  Notes  repurchased,  redeemed  or retired  pursuant to
clause (y) and (z) above may not be reissued and, provided further, that, in the
case of clause (5) above,  so long as no Default or Event of Default then exists
or would result  therefrom  Holdings may repurchase,  redeem or otherwise retire
outstanding  the  then  outstanding  principal  amount  of the  Holdings  Senior
Subordinated   Note  solely  with  the  proceeds  of  Holdings  Note   Permitted
Refinancing  Indebtedness;"  10. Section 8.16 of the Credit  Agreement is hereby
amended by inserting the text "currency of payments," immediately after the text
"except  for changes  in"  appearing  therein.  11. The  definition  of the term
"Permitted  Holders"  contained in Section 10 of the Credit  Agreement is hereby
amended by deleting  the text "the  Parent"  appearing  in said  definition  and
inserting the word  "Holdings" in lieu thereof.  12. The  definition of the term
"Consolidated  Debt"  contained in Section 10 of the Credit  Agreement is hereby
amended by (a) deleting the word "and" appearing  immediately  before clause (y)
of said definition and inserting a comma in lieu thereof,  and (b) inserting the
text "and (z)  solely for the  purpose  of  calculating  the  Leverage  Ratio in
determining  compliance  with  Section  8.08,  the  then  outstanding  aggregate
principal  amount  of the  Holdings  Senior  Subordinated  Note at the time such
determination is made pursuant to Section 8.08 (it being understood that for all
other purposes under this Agreement including,  without limitation, for purposes
of calculating  the Leverage Ratio in determining  the Applicable  Margin or the
Applicable Commitment Fee Percentage, the exclusion set forth in this clause (z)
shall not  apply)"  immediately  following  clause (y) of said  definition.  13.
Section  10 of the  Credit  Agreement  is hereby  further  amended by adding the
following new defined terms in the correct alphabetical order to said Section:

          "Cabot Corp." shall mean Cabot  Corporation,  a Delaware  corporation.
- ----- -----

          "Cabot CSC" shall mean Cabot CSC corporation,  a Delaware  corporation
and a Wholly-Owned Subsidiary of Cabot Corp.

          "Cabot Equity  Repurchase" shall mean (x) the repurchase of all of the
common stock and  preferred  stock of Holdings held by Cabot CSC pursuant to the
Holdings Stock Purchase Agreement,  which common stock and preferred stock shall
be  placed  into  treasury  immediately   following  the  consummation  of  such
repurchase and (y) the  consummation of the other  transactions  contemplated by
Holdings Stock Purchase Agreement.

          "Holdings  Note  Permitted  Refinancing  Indebtedness"  shall mean any
Indebtedness   incurred  by  Holdings  which  is  pari  passu  with  all  senior
Indebtedness  of Holdings,  but  subordinated  to all of  Holding's  Obligations
hereunder and under any other Credit Document,  including without limitation any
obligations  of  Holdings  under  the  Holdings  Guaranty,  so long as (i)  such
Indebtedness  shall require no  amortization  (or similar  arrangement),  or any
other  scheduled  maturity of the principal  amount thereof on any date which is
earlier than the maturity date for the Holdings Senior  Subordinated  Note, (ii)
the interest rate for such  Indebtedness  shall not be in excess of the interest
rate  applicable to the Holdings  Senior  Subordinated  Note and (iii) the terms
governing  any such  Indebtedness  shall not contain any  provision  (including,
without limitation,  covenants,  defaults and remedies) which, in the opinion of
the Administrative Agent, is more restrictive than those provisions contained in
the Holdings Note Purchase  Agreement  and/or the Holdings  Senior  Subordinated
Note and, in any event,  shall be reasonably  satisfactory to the Administrative
Agent.

          "Holdings  Note  Purchase  Agreement"  shall  mean that  certain  note
purchase agreement, dated as of August 15, 2003, by and between Holdings, as the
issuer and Deutsche Bank  Securities Inc. (in its individual  capacity),  as the
initial purchaser, providing for the issuance by Holdings of the Holdings Senior
Subordinated  Note on terms and conditions  substantially  the same as those set
forth in the form of such agreement  delivered to each of the Banks prior to the
Second  Amendment  Effective  Date,  and as such  agreement  is in effect on the
Second Amendment Effective Date.

          "Holdings  Senior  Subordinated  Note" shall mean the unsecured senior
subordinated note of Holdings  initially issued to Deutsche Bank Securities Inc.
(in  its  individual  capacity)  pursuant  to the  the  Holdings  Note  Purchase
Agreement,  in an aggregate  principal  amount equal to $15,000,000 due July 15,
2005 and as such note is in  effect  on the  Second  Amendment  Effective  Date,
provided that (i) the  obligations of Holdings  under,  and in connection  with,
such note shall be  subordinated to all of Holding's  Obligations  hereunder and
under any other Credit Document, including without limitation any obligations of
Holdings  under the Holdings  Guaranty  and (ii) any other terms and  conditions
contained in such note shall be substantially the same as those set forth in the
form of such note  delivered to each of the Banks prior to the Second  Amendment
Effective Date.

          "Holdings  Stock  Purchase  Agreement"  shall mean that certain  Stock
Purchase Agreement,  dated as of June 27, 2003, by and among Holdings, Cabot CSC
and Cabot Corp, as such agreement is in effect on the Second Amendment Effective
Date.

          "Second   Amendment"   shall  mean  the  Second  Amendment  to  Credit
Agreement,  dated as of August 8, 2003, among Holdings,  the Borrowers,  each of
the Subsidiary Guarantors, the Administrative Agent and the Banks party thereto.

          "Second  Amendment  Effective Date" shall have the meaning provided in
Part B, Section 4 of the Second Amendment.

          14.  Section  13.13 of the  Credit  Agreement  is  hereby  amended  by
inserting the following new Sections  13.13(c) and (d) immediately after Section
13.13(b):

          "(c) Each Credit Party hereby represents and acknowledges that, to the
best of its knowledge,  neither the  Administrative  Agent nor any Bank, nor any
employees or agents of, or other persons  affiliated  with,  the  Administrative
Agent or any Bank,  have directly or  indirectly  made or provided any statement
(oral or written) to such Credit Party or to any of its employees or agents,  or
other  persons  affiliated  with or related to such Credit  Party (or, so far as
such  Credit  Party is aware,  to any other  person),  as to the  potential  tax
consequences of any transaction contemplated hereby.

          (d) Neither the Administrative Agent nor the Banks provide accounting,
tax  or  legal  advice.   Notwithstanding  any  express  or  implied  claims  of
exclusivity or proprietary rights,  each Credit Party, the Administrative  Agent
and each  Bank  hereby  agree  and  acknowledge  that  each  Credit  Party,  the
Administrative Agent and each Bank (and each of their employees, representatives
or other agents) are  authorized  to disclose to any and all persons,  beginning
immediately upon commencement of their discussions and without limitation of any
kind,  the tax  treatment  and tax  structure  of any  transaction  contemplated
hereby, and all materials of any kind (including opinions or other tax analyses)
that are  provided to any Credit  Party,  the  Administrative  Agent or any Bank
relating to such tax treatment and tax  structure.  In this regard,  each Credit
Party,  the  Administrative  Agent and each Bank  acknowledge and agree that the
disclosure  of  the  tax   treatment  and  tax  structure  of  any   transaction
contemplated  hereby  is  not  limited  in  any  way by an  express  or  implied
understanding or agreement,  oral or written (whether or not such  understanding
or agreement is legally  binding).  For  purposes of this  authorization,  "tax"
means United States Federal income tax, "tax  treatment"  means the purported or
claimed  Federal income tax treatment of the  transaction,  and "tax  structure"
means any fact that may be relevant to  understanding  the  purported or claimed
Federal  income tax  treatment  of any  transaction  contemplated  hereby.  This
paragraph is intended to reflect the  understanding  of each Credit  Party,  the
Administrative Agent and each Bank that no transaction  contemplated hereby is a
"confidential  transaction"  as that phrase is used in Treasury  Regulation  ss.
1.6011-4(b)(3)(i),  and shall be interpreted in a manner  consistent  therewith.
Nothing  herein is intended to imply that any Credit Party,  the  Administrative
Agent nor any Bank made or provided a statement, oral or written, to, or for the
benefit  of, any of each other as to any  potential  tax  consequences  that are
related to, or may result from, the transactions contemplated hereby."

B.  Miscellaneous  Provisions

          1. In order to induce the Banks to enter into this Amendment,  each of
the Credit Parties hereby  represents and warrants that (i) the  representations
and warranties of each such Credit Party  contained in the Credit  Agreement are
true and  correct in all  material  respects  on and as of the Second  Amendment
Effective Date (as defined  below)  (except with respect to any  representations
and warranties  limited by their terms to a specific  date,  which shall be true
and correct in all material  respects as of such date), and (ii) there exists no
Default or Event of Default under the Credit  Agreement on the Second  Amendment
Effective Date, in each case before and after giving effect to this Amendment.

          2. This  Amendment  is limited as  expressly  specified  and shall not
constitute  an  amendment,  modification,  acceptance  or  waiver  of any  other
provision  of the Credit  Agreement,  any other  Credit  Document nor any of the
Obligations.

          3. 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.  4. This  Amendment  shall become  effective on the date (the
"Second  Amendment  Effective  Date")  when (i)  Holdings,  the  Borrowers,  the
Subsidiary  Guarantors,  the  Administrative  Agent and the Required Banks shall
have signed a counterpart  hereof  (whether the same or different  counterparts)
and  shall  have  delivered  (including  by way of  telecopier)  the same to the
Administrative Agent, (ii) Holdings shall have, or shall have caused to be, paid
to each Bank which executes and delivers (including by way of telecopier) to the
Administrative Agent a counterpart of this Amendment on or before 5:00 P.M. (New
York time) on August 13, 2003,  an amendment fee equal to 0.25% of the aggregate
principal  amount of such  Bank's  outstanding  Term Loans  and/or  such  Bank's
Revolving Loan Commitments,  in each case, as of the Second Amendment  Effective
Date and (iii)  Holdings shall have, or shall have caused to be, paid in full to
the  Administrative  Agent all  costs,  fees and  expenses  (including,  without
limitation,   all   reasonable   legal  fees  and   expenses)   payable  to  the
Administrative  Agent to the extent then due. 5. Each of the Credit Parties as a
debtor, a grantor, a pledgor, a guarantor,  an assignor, or in any other similar
capacity in which such Credit Party  grants  liens or security  interests in its
property or otherwise acts as accommodation party or guarantor,  as the case may
be,  hereby (i)  ratifies  and  reaffirms  all of its  payment  and  performance
obligations,  contingent  or  otherwise,  under each of the Credit  Documents to
which it is a party  (after  giving  effect  hereto) and (ii) to the extent such
Credit  Party  granted  liens on or security  interests  in any of its  property
pursuant to any such Credit Document as security for or otherwise guaranteed any
of the Obligations under or with respect to the Credit  Documents,  ratifies and
reaffirms such guarantee and grant of security  interests and liens and confirms
and agrees that such security  interests and liens  hereafter  secure all of the
Obligations as amended  hereby.  Each of the Credit  Parties hereby  consents to
this Amendment and  acknowledges  that each of the Credit  Documents  remains in
full force and effect and is hereby ratified and  reaffirmed.  6. From and after
the Second Amendment  Effective Date, all references in the Credit Agreement and
in the other Credit  Documents  shall be deemed to be  referenced  to the Credit
Agreement as modified hereby. * * *



                                      -10-

          IN WITNESS  WHEREOF,  the undersigned have caused this Amendment to be
duly executed and delivered as of the date first above written.

                                       AEARO CORPORATION


                                       By:______________________________________
                                              Name:
                                              Title:

                                       AEARO COMPANY


                                       By:______________________________________
                                              Name:
                                              Title:

                                       AEARO CANADA LIMITED


                                       By:______________________________________
                                              Name:
                                              Title:

                                       AEARO LIMITED


                                       By:______________________________________
                                              Name:
                                              Title:

                                       CABOT SAFETY INTERMEDIATE CORPORATION


                                       By:______________________________________
                                              Name:
                                              Title:

                                       CSC FSC, INC.


                                       By:______________________________________
                                              Name:
                                              Title:



DEUTSCHE BANK TRUST COMPANY AMERICAS, Individually and as Administrative Agent



                                      By:_______________________________________
                                             Name:
                                             Title:


                                      [OTHER BANK]



                                      By:_______________________________________
                                             Name:
                                             Title:

                                      By:_______________________________________
                                                          Name:
                                                          Title: