EXHIBIT 10.4
 
================================================================================


                   MORTGAGE, SECURITY AGREEMENT, ASSIGNMENT
                    OF RENTS AND LEASES AND FIXTURE FILING

                                      by

                       WAHLCO ENGINEERED PRODUCTS INC.,

                                                        Mortgagor,

                                      to

               each of the Lenders identified on Annex 1 hereto,

                                                        Mortgagee,


================================================================================

This instrument was prepared by the 
attorney listed below, in consultation 
with counsel in the State, and after 
recording should be returned to:

HOWARD, SMITH & LEVIN LLP
1330 Avenue of the Americas
New York, New York  10019
Attention:  Andrew Baraff, Esq.

 
                               TABLE OF CONTENTS

 
 
                                                                        Page
                                                                      
                                   ARTICLE I
                                  DEFINITIONS

SECTION 1.1.   Terms Defined in Credit Agreement.......................    5
                                                                           
SECTION 1.2.   Terms Defined in This Mortgage..........................    6
                                                                          
SECTION 1.3.   Terms Defined in Uniform Commercial Code................   10
                                                                          
SECTION 1.4.   Rules of Interpretation.................................   10


                                  ARTICLE II
                     COVENANTS AND AGREEMENTS OF MORTGAGOR

SECTION 2.1.   Payment of Secured Obligations..........................   11
                                                                          
SECTION 2.2.   Further Assurances......................................   11
                                                                          
SECTION 2.3.   Care of the Mortgaged Property..........................   12
     (a)  Operation and Maintenance....................................   12
     (b)  Repair and Replacement.......................................   12
     (c)  Use..........................................................   12
                                                                          
SECTION 2.4.   Compliance With Laws and Payment of Impositions.........   12
                                                                           
SECTION 2.5.   Insurance and Casualty..................................   12
     (a)  Required Insurance...........................................   12
     (b)  Form.........................................................   13
     (c)  Notice of Loss...............................................   13
     (d)  No Separate Insurance........................................   13
     (e)  Assignment of Policies On Foreclosure........................   13
                                                                           
SECTION 2.6.   Condemnation............................................   14 
     (a)   Notice of Loss..............................................   14
     (b)   Protection of Mortgaged Property............................   14
                                                                           
SECTION 2.7.   Application of Insurance Proceeds and Condemnation          
                Proceeds...............................................   14
     (a)  Proceeds Payable to Mortgagee................................   14
 

 
 
                                                                         
     (b)  Prosecution of Claim for Loss................................    15 
                                                                            
SECTION 2.8.   Transfer Restrictions...................................    15
                                                                            
SECTION 2.9.   Mortgagee's Right to Perform............................    15
                                                                            
SECTION 2.10.  Subrogation.............................................    15
                                                                            
SECTION 2.11.  Inspection of Mortgaged Property........................    16
                                                                            
SECTION 2.12.  Certain Tax Law Changes.................................    16
                                                                            
SECTION 2.13.  Future Advances.........................................    16
                                                                            
SECTION 2.14.  Covenants in Loan Documents.............................    17


                                  ARTICLE III
                        REPRESENTATIONS AND WARRANTIES

SECTION 3.1.  .........................................................    17
     (a)  Title........................................................    17
     (b)  Chain of Title...............................................    17

SECTION 3.2.   Valid Lien and Security Interest........................    17

                                  ARTICLE IV
                     SECURITY AGREEMENT AND FIXTURE FILING

SECTION 4.1.   Security Agreement......................................    18
     (a)  Grant of Security Interest...................................    18
     (b)  Remedies.....................................................    18 

SECTION 4.2.   Fixture Filing..........................................    18
                                                                            
SECTION 4.3.   Security Deposit Collateral.............................    19
                                                                            
SECTION 4.4.   Additional Covenants....................................    19
 

 
 
                                                                         
                                   ARTICLE V
                        ASSIGNMENTS OF RENTS AND LEASES

SECTION 5.1.   Assignment of Rents and Leases..........................    19 
     (a)  Assignment of Rents..........................................    19
     (b)  License to Collect Rents.....................................    19
     (c)  Termination of License Upon Event of Default.................    20
     (d)  Direction to Tenants.........................................    20
     (e)  No Release of Tenants........................................    20
     (f)  No Liability of Mortgagee....................................    20
     (g)  No Existing Leases...........................................    21


                                  ARTICLE VI
                             DEFAULTS AND REMEDIES

SECTION 6.1.   Events of Defaults......................................    21  

SECTION 6.2.   Remedies................................................    21
     (a)  General......................................................    21
     (b)  Foreclosure..................................................    22
     (c)  Mortgagee May Bid............................................    22
     (d)  Acceleration of Secured Obligations..........................    22

SECTION 6.3.   Possession of Property..................................    23
     (a)  Mortgagor to Vacate Property.................................    23
     (b)  Payment for Use and Occupancy................................    23

SECTION 6.4.   Appointment of Receiver.................................    24
               
SECTION 6.5.   Waiver of Stay, Extension, Moratorium and Marshalling
                Laws and Equity of Redemption..........................    24

SECTION 6.6.   Mortgagee Authorized to Execute Documents...............    24
                                                                            
SECTION 6.7.   Collateral Situated in More than One County.............    25
                                                                            
SECTION 6.8.   Collateral in Other States..............................    25
                                                                            
SECTION 6.9.   Application of Proceeds.................................    25
                                                                            
SECTION 6.10.  Setoff..................................................    26
 

 
 
                                                                         
SECTION 6.11.  Receipt a Sufficient Discharge to Purchaser.............    26
                                                                            
SECTION 6.12.  Sale a Bar Against Mortgagor............................    26
                                                                            
SECTION 6.13.  Remedies Cumulative; Waiver.............................    26
                                                                            
SECTION 6.14.  No Liability of Mortgagees..............................    27


                                  ARTICLE VII
                             CONCERNING MORTGAGEE

SECTION 7.1.   [Intentionally Omitted].................................    27
               
                                 ARTICLE VIII
                                 MISCELLANEOUS
               
SECTION 8.1.   Termination; Defeasance.................................    27
                                                                            
SECTION 8.2.   Rights Cumulative; Waivers..............................    28
                                                                            
SECTION 8.3.   Fees and Expenses.......................................    28
                                                                            
SECTION 8.4.   Indemnification.........................................    28
     (a)  Indemnity....................................................    28
     (b)  Third-Party Beneficiaries....................................    29

SECTION 8.5.   Notices.................................................    29

SECTION 8.6.   Amendment and Waiver....................................    30

SECTION 8.7.   Expenses of Mortgagor's Agreements and Duties...........    30
                                                                            
SECTION 8.8.   Mortgagee's Right to Use Agents and to Act in Name           
                of Mortgagor...........................................    30
                                                                            
SECTION 8.9.   No Compensation or Expense..............................    30
               
SECTION 8.10.  Limitation of Obligations with Respect to Mortgaged 
                Property...............................................    31
     (a)  Reasonable Care..............................................    31
     (b)  No Obligations...............................................    31 

SECTION 8.11.  Time of the Essence.....................................    31
 

 
 
                                                                         
SECTION 8.12.  Inconsistency with Loan Documents.......................    31
                                                                            
SECTION 8.13.  Severability............................................    31
                                                                            
SECTION 8.14.  Headings................................................    32
                                                                            
SECTION 8.15.  Assignment; Benefit.....................................    32
                                                                            
SECTION 8.16.  GOVERNING LAW...........................................    32
                                                                            
SECTION 8.17.  WAIVER OF JURY TRIAL....................................    32
                                                                            
SECTION 8.18.  CONSENT TO JURISDICTION.................................    33

SECTION 8.19.  Limitation on Interest Payable..........................    33
                                                                            
SECTION 8.20.  Covenants To Run With the Land..........................    34
                                                                            
SECTION 8.21.  No Merger...............................................    34
                                                                            
SECTION 8.22.  Relationship............................................    34


                                  ARTICLE IX
                             ENVIRONMENTAL MATTERS

SECTION 9.1.   Notice of Environmental Matters.........................    35
     (a)  Delivery of Notice...........................................    35
     (b)  Contents of Notice...........................................    35

SECTION 9.2.   Obligations of Mortgagor................................    35


                                   ARTICLE X
                         LOCAL JURISDICTION PROVISIONS

SECTION 10.1.  Mortgage Covenants........................................  35
                                                                            
SECTION 10.2.  Statutory Conditions......................................  35
                                                                            
SECTION 10.3.  No Waiver.................................................  36
                                                                            
SECTION 10.4.  Written Agreement.........................................  36
 

 
 
                                                                         
SECTION 10.5.  Open-End Mortgage.........................................  36
                                                                            
SECTION 10.6.  Information Under Uniform Commercial Code.................  36
                                                                         
SECTION 10.7.  Notice Pursuant to 18-A M.R.S.A. (S) 5-508................  37
               
SECTION 10.8   Authority of Wexford Management, LLC......................  38
 

                                   EXHIBITS

EXHIBIT A    -   DESCRIPTION OF LAND
EXHIBIT B    -   MATERIAL AGREEMENTS
EXHIBIT C    -   PERMITTED ENCUMBRANCES
EXHIBIT D    -   INFORMATION FOR FINANCING STATEMENTS

 
                   MORTGAGE, SECURITY AGREEMENT, ASSIGNMENT
                     OF RENTS AND LEASES AND FIXTURE FILING


          MORTGAGE, SECURITY AGREEMENT, ASSIGNMENT OF RENTS AND LEASES AND
FIXTURE FILING (this "Mortgage"), dated as of February 25, 1999, is given by
                      --------                                              
WAHLCO ENGINEERED PRODUCTS INC., a Maine corporation (together with its
successors and permitted assigns, "Mortgagor"), to WEXFORD MANAGEMENT LLC, a
                                   ---------                                
Connecticut limited liability company (together with its successors and
permitted assigns, the "Agent"), and to each of the Lenders (as hereinafter
                        -----                                              
defined).

                                  BACKGROUND:

          A.  On January 13, 1999, pursuant to an Agreement and Plan of Merger,
dated November 9, 1998 (the "Merger Agreement"), among Wahlco Environmental
                             ----------------                              
Systems, Inc. ("Wahlco"), Thermatrix Inc. ("Thermatrix") and TMX Acquisition Sub
                ------                      ----------                          
I, Inc., a wholly-owned subsidiary of Thermatrix ("Merger Sub"), Merger Sub
                                                   ----------              
merged with and into Wahlco (the "Merger"), and Wahlco became a wholly-owned
                                  ------                                    
subsidiary of Thermatrix at the effective time of the Merger (the "Effective
                                                                   ---------
Date").
- ----   

          B.  Concurrently with the execution and delivery hereof, Wahlco and
Thermatrix (the "Borrowers") are entering into a Second Amended and Restated
                 ---------                                                  
Credit Agreement, dated as of the date hereof, with the Lenders and the Agent
(as the same may hereafter be modified, extended, replaced or otherwise amended,
the "Credit Agreement"), pursuant to which the Borrowers shall be jointly and
     ----------------                                                        
severally liable for the payment and performance of all of the obligations and
liabilities to the Lenders and the Agent set forth therein and in the other Loan
Documents (as hereinafter defined).

          C.  Prior to the Merger, Mortgagor was, and after the Merger Mortgagor
remains, a subsidiary of Wahlco.

          D.  Concurrently with the execution and delivery of the Credit
Agreement, Mortgagor is executing and delivering the Guarantee (as hereinafter
defined) to the Agent and the Lenders.

          E.  It is a condition to the effectiveness of the Credit Agreement
that, among other things, Mortgagor execute and deliver this Mortgage granting
to the Agent and each of the Lenders (together, "Mortgagee") the liens and
                                                 ---------                
security interests in the collateral described herein, all as set forth in the
Credit Agreement.

          F.  Mortgagor will receive substantial direct and indirect benefits
from the Lenders and the Mortgagee entering into the Credit Agreement.


 
                                GRANT OF LIEN:

          NOW THEREFORE, to secure the full and timely payment and performance
of all of the Secured Obligations (as hereinafter defined), Mortgagor hereby
irrevocably grants, bargains, sells, mortgages, warrants, aliens, devises,
releases, hypothecates, pledges, transfers and conveys to each Mortgagee, as
tenants in common, and to the extent the same constitutes Personal Property (as
hereinafter defined) grants to each Mortgagee, as tenants in common, a security
interest in, forever, any and all the following (collectively, the "Mortgaged
                                                                    ---------
Property"):
- --------   

          A.  Land.  The land described on Exhibit A, together with all and
              ----                         ---------                       
singular the tenements, rights, easements, hereditaments, rights of way,
privileges, liberties, appendages and appurtenances now or hereafter belonging
or in any way appertaining to such land (including, without limitation, all
rights relating to storm and sanitary sewer, water, gas, electric, railway and
telephone services); all estate, claim, demand, right, title or interest of
Mortgagor in and to any street, road, highway, or alley (vacated or otherwise)
adjoining such land or any part thereof; and all Mortgagor's right, title and
interest, if any, in and to any strips and gores belonging, adjacent or
pertaining to such land (collectively, the "Land").
                                            ----   

          B.  Improvements and Fixtures.  All buildings, structures,
              -------------------------                             
replacements, fixtures and fittings and other improvements and property of every
kind and description now or hereafter affixed or attached to the Land, including
water, sanitary and storm sewer, drainage, electricity, steam, gas, telephone
and other utility facilities, parking areas, roads, driveways, walks and other
site improvements together with all estate, right, title and interest, if any,
of Mortgagor in, to or under all equipment, appliances, machinery, tools,
accessories, apparatus, building or construction materials, and other articles
of any kind or nature whatsoever affixed or attached to the Land, including all
motors, boilers, engines, pumps, compressors, tanks and similar devices, all
heating, electrical, lighting, power, plumbing, air conditioning, refrigeration,
ventilation and mechanical equipment, all pipes, ducts, conduits, cables and
other transmission devices and equipment, and all elevators, escalators, lifts,
walls, partitions, doors, windows and other equipment and property affixed to
the Land that is real estate or real property or fixtures under applicable law
of the State (as hereinafter defined) (collectively, the "Improvements", and
                                                          ------------      
together with the Land, the "Property").
                             --------   

          C.  Minerals and Related Rights.  All of Mortgagor's right, title and
              ---------------------------                                      
interest in, to and under all rights, royalties and profits with respect to all
minerals, coal, oil and gas and other substances of any kind or character on or
underlying the Land, together with all water and water rights (whether riparian,
appropriative, or otherwise and whether or not appurtenant).

          D.  Air and Development Rights.  All of Mortgagor's right, title and
              --------------------------                                      
interest in, to and under all air rights, development rights or credits, zoning
rights or other similar 

                                      -2-

 
rights or interests which benefit or are appurtenant to the Property.

          E.  Parking Rights.  All estate, right, title, interest and other
              --------------                                               
claim of Mortgagor, if any, with respect to any parking facilities located other
than on the Property and used or intended to be used in connection with the
operation, ownership or use of the Property, any and all replacements and
substitutions for the same, and any other parking rights, easements, covenants
and other interests in parking facilities acquired by Mortgagor for the use of
tenants or occupants of the Improvements.

          F.  Tangible Property.  All building materials, goods, construction
              -----------------                                              
materials, appliances (including, without limitation, stoves, ranges, ovens,
disposals, refrigerators, water fountains, water coolers, fans, heaters,
dishwashers, clothes washers and dryers, water heaters, hood and fan
combinations, kitchen equipment, laundry equipment, kitchen cabinets and other
similar equipment), stocks, beds, mattresses, bedding and linens, supplies,
blinds, window shades, drapes, carpets, floor coverings, office equipment,
trees, timber, crops, growing plants and shrubberies, control devices, equipment
and machinery (including window cleaning, building cleaning, swimming pool,
recreational, monitoring, garbage, pest control and other equipment), motor
vehicles, tools, furnishings, furniture, lighting, all nonstructural additions
to the Property and all other tangible property of any kind or character,
together with all replacements thereof, located on or in or used in connection
with the complete and comfortable use, enjoyment, occupation, operation,
development and maintenance of the Property, regardless of whether or not
located on or in the Property or located elsewhere for purposes of storage,
fabrication or otherwise, exclusive of any of the foregoing items leased by
Mortgagor or owned by tenants (other than Mortgagor) of portions of the Property
(collectively, the "Tangible Property").
                    -----------------   

          G.  Material Agreements.  All estate, right, title and interest of
              -------------------                                           
Mortgagor in, to or under all contracts and agreements (including those, if any,
described on Exhibit B) and all title insurance policies, guarantees and
             ---------                                                  
warranties and other contracts and agreements including any agreements taken by
Mortgagor by assignment, now or hereafter relating to the Property, including
all water, sanitary and storm sewer, drainage, electricity, steam, gas,
telephone and other utility supply and service contracts (collectively,
                                                                       
"Material Agreements").
- --------------------   

          H.  Leases and Rents.  All Leases (as hereinafter defined), now or
              ----------------                                              
hereafter in effect for the use, possession or occupancy of the Property or any
part thereof, and all estate, right, title and interest of Mortgagor in and to
any and all rents, profits, issues, royalties, revenues and other benefits
derived from the sale or lease of the Property or any other portion of the
Mortgaged Property or from or under any of the Leases (collectively, "Rents").
                                                                      -----   

          I.  Security Deposit Collateral.  All cash, securities, letters of
              ---------------------------                                   
credit, guarantees, surety bonds and similar instruments (collectively, the
"Security Deposit 
 ----------------

                                      -3-

 
Collateral") from time to time delivered to Mortgagor as security for the
- ----------
performance of any tenant under a Lease, but excluding any Security Deposit
Collateral which, by its terms, is unassignable or may not be pledged or
transferred.

          J.  Intangibles.  All goodwill, trademarks, trade names, option
              -----------                                                
rights, purchase contracts, books and records and general intangibles of
Mortgagor relating to the Property and all accounts, contract rights,
instruments, chattel paper and other rights of Mortgagor for the payment of
money for property sold or lent, for services rendered, for money lent, or for
advances or deposits made, and any other intangible property of Mortgagor
relating to the Property, but specifically excluding rights of Mortgagor in, to
and under any Material Agreements (collectively, the "Intangibles").
                                                      -----------   

          K.  Plans.  All plans and specifications, designs, drawings and other
              -----                                                            
information, materials and matters heretofore or hereafter prepared relating to
the Property.

          L.  Permits.  All licenses, authorizations, certificates, variances,
              -------                                                         
consents, approvals and other permits now or hereafter relating to the Property
(collectively, the "Permits"), excluding from the grant under this Granting
                    -------                                                
Clause (but not from the definition of the term "Permits" for the other purposes
hereof) Permits that cannot be transferred or encumbered by Mortgagor without
causing a default thereunder or a termination thereof.

          M.  Leases of Furniture, Furnishings and Equipment.  All right, title
              ----------------------------------------------                   
and interest of Mortgagor as lessee in, to and under any leases of furniture,
furnishings and equipment now or hereafter installed in or at any time used in
connection with the Property.

          N.  Condemnation Proceeds.  All Condemnation Proceeds (as hereinafter
              ---------------------                                            
defined).

          O.  Insurance Proceeds.  All Insurance Proceeds (as hereinafter
              ------------------                                         
defined).

          P.  Awards.  All rights and interests of Mortgagor against others,
              ------                                                        
including adjoining property owners and governmental entities arising out of
damage to the Mortgaged Property, including damage due to environmental injury
or release of Hazardous Materials (as hereinafter defined).

          Q.  Further Interests.  All greater or additional estate, right, title
              -----------------                                                 
and interest of Mortgagor in, to or under any of the Mortgaged Property
hereafter acquired by Mortgagor, and all right, title and interest of Mortgagor
in, to, under or derived from all extensions, improvements, betterments,
renewals, substitutions and replacements of, and additions and appurtenances to,
any of the Mortgaged Property hereafter acquired by or released to Mortgagor
(including any Mortgaged Property acquired by Mortgagor by foreclosure or deed
in lieu of foreclosure pursuant to the terms of any mortgage note held by
Mortgagor) or 

                                      -4-

 
constructed or located on, or attached to, the Property, in each case,
immediately upon such acquisition, release, construction, location or
attachment, without any further conveyance, mortgage, assignment or other act by
Mortgagor; and all right, title and interest of Mortgagor in, to, under or
derived from all other property and rights which by any instrument executed by
Mortgagor or any Person on its behalf are otherwise subjected to the lien of
this Mortgage.

          R.  Proceeds.  All proceeds of any voluntary or involuntary conversion
              --------                                                          
of any of the foregoing into cash or other property, including, without
limitation, proceeds of insurance and condemnation awards and liquidated claims.

          S.  Other Property.  All other property and rights of Mortgagor of
              --------------                                                
every kind and character relating to and used in connection with the Mortgaged
Property, and all proceeds and products of any of the foregoing; provided, that
                                                                 --------      
the Mortgaged Property shall not include (i) any property, rights or licenses to
the extent the granting of a Lien thereon would be contrary to applicable law or
(ii) any rights under any license agreement where such license agreement would
be terminable by the counterparty thereto if Mortgagor's interest therein were
subject to the security interest created hereby (but only to the extent such
right to terminate is enforceable under applicable law).  Each such license
agreement existing on the date hereof is set forth in Schedule 3(b) of the
Disclosure Letter.

          TO HAVE AND TO HOLD the Mortgaged Property unto each Mortgagee, and
its successors and assigns, forever, under and subject to the terms and
conditions of the Credit Agreement and this Mortgage, for the security and
enforcement of the prompt and complete payment, performance and observance when
due of all of the Secured Obligations.

          PROVIDED ALWAYS that this Mortgage is upon the express condition that
the Mortgaged Property shall be released from the lien of this Mortgage in the
manner and at the time provided in Section 8.1 of this Mortgage.

          MORTGAGOR FURTHER COVENANTS AND AGREES WITH MORTGAGEE AS FOLLOWS:


                                   ARTICLE I

                                  DEFINITIONS


          SECTION 1.1.  Terms Defined in Credit Agreement.  The following terms,
                        ---------------------------------                       
and all other terms defined in the Credit Agreement and not otherwise defined
herein, have, as 

                                      -5-

 
used herein, the respective meanings provided for in the Credit Agreement:

          Affiliate              
          Business Days          
          Collateral             
          Disclosure Letter      
          Liens                  
          Loans                  
          Loan Documents         
          Loan Party             
          Material Adverse Effect
          Note                   
          Overdue Rate           
          Person                 
          Required Lenders       
          Responsible Officer    
          Subsidiary              

          SECTION 1.2.  Terms Defined in This Mortgage. The following terms, as
                        ------------------------------
used herein, have the following meanings:

          "Bankruptcy Code" means the United States Bankruptcy Code, Title 11 of
           ---------------                                                      
the United States Code, (S) 101 et seq., as amended from time to time.

          "Casualty" means any damage to, destruction or loss of or other
           --------                                                      
casualty with respect to any of the Mortgaged Property.

          "Condemnation" means any actual or threatened condemnation, taking or
           ------------                                                        
exercise of the power of eminent domain or similar action or proceeding.

          "Condemnation Proceeds" means, at any time, any award or payment paid
           ---------------------                                               
or payable by reason of any Condemnation, whether from the exercise of the right
of Condemnation or any transfer made in lieu thereof or any injury to or
decrease in value of any property in connection with a Condemnation, including
all amounts paid pursuant to any agreement with any condemning authority that
has been made in settlement of any proceeding relating to a Condemnation and any
interest earned on such award, payment or amounts, less the reasonable costs and
expenses (including reasonable attorneys' fees and expenses) of Mortgagor and
Mortgagee in collecting such award payment or amounts, which costs and expenses
shall be paid out of such award, payment or amounts.

          "Credit Agreement" is defined in Recital Paragraph B.
           ----------------                           

                                      -6-

 
          "Effective Date" is defined in Recital Paragraph A.
           --------------                                    

          "Event of Default" is defined in Section 6.1.
           ----------------                            

          "Flood Zone" is defined in Section 3.5.
           ----------                            

          "Guarantee" means the Amended and Restated Guaranty, dated as of the
           ---------                                                          
date hereof, by Mortgagor (among others) to Mortgagee, as the same may hereafter
be modified, extended, replaced or otherwise amended.

          "Impositions" means all taxes (including real estate taxes and sales
           -----------                                                        
and use taxes), assessments (including all assessments for public improvements
or benefits, whether or not commenced or completed prior to the date hereof),
water, sewer or other rents, rates and charges, excises, levies, license fees,
permit fees, inspection fees and other authorization fees and other charges, in
each case whether general or special, ordinary or extraordinary, foreseen or
unforeseen, of every character (including all interest and penalties thereon),
which at any time may be assessed, levied, confirmed or imposed on or in respect
of, or be a Lien upon, (i) the Mortgaged Property or any interest therein, (ii)
any occupancy, use or possession of, or activity conducted on, the Mortgaged
Property, (iii) the Rents from the Mortgaged Property or the use or occupancy
thereof, or (iv) the Secured Obligations, but excluding income, excess profits,
franchise, capital stock, estate, inheritance, succession, gift or similar taxes
of Mortgagor or Mortgagee, except to the extent that such taxes of Mortgagor or
Mortgagee are imposed in whole or in part in lieu of, or as a substitute for,
any taxes which are or would otherwise be Impositions.

          "Improvements" is defined in Granting Clause B.
           ------------                                  

          "Indemnified Party" means, with respect to a Person entitled to the
           -----------------                                                 
benefit of an indemnity, such Person's officers, directors, shareholders,
partners, members, employees, agents and representatives.

          "Insurance Policies" means the insurance policies and coverages
           ------------------                                            
required to be maintained by Mortgagor pursuant to Section 2.5.

          "Insurance Proceeds" means, at any time, (x) all proceeds or payments
           ------------------                                                  
to which Mortgagor may be or become entitled under any of the Insurance Policies
and any and all unearned premiums accrued, accruing or to accrue under any
Insurance Policies and all proceeds of the conversion, voluntary or involuntary,
of any of the foregoing into cash or liquidated claims, plus any interest earned
on such proceeds, payments or amounts, less (y) the reasonable costs and
expenses of Mortgagor and Mortgagee in collecting such proceeds, payments or
amounts, which costs and expenses shall be paid out of such proceeds, payments
or amounts.

                                      -7-

 
          "Insurance Requirements" means all provisions of the Insurance
           ----------------------                                       
Policies, all requirements of the issuer of any of the Insurance Policies and
all orders, rules, regulations and any other requirements of the National Board
of Fire Underwriters (or any other body exercising similar functions) binding
upon Mortgagor or applicable to the Mortgaged Property, any adjoining vaults,
sidewalks, parking areas or driveways or any use or condition thereof.

          "Intangibles" is defined in Granting Clause J.
           -----------                                  

          "Land" is defined in Granting Clause A.
           ----                                  

          "Lease" means any lease, tenancy, subtenancy, license, franchise,
           -----                                                           
concession or other use or occupancy agreement relating to the Property,
together with any guarantee of the obligations of the landlord or the tenant
thereunder, or any occupancy or right to possession under Section 365 of the
Bankruptcy Code in the event of the rejection of any of the foregoing by the
landlord or its trustee pursuant to such Section; "landlord" means the landlord,
sublandlord, lessor, sublessor, franchisor or other grantor of a right of use or
occupancy under a Lease and any guarantor of its obligations thereunder; and
"tenant" means the tenant, subtenant, lessee, sublessee, licensee, franchisee,
concessionaire or other occupant under a Lease and any guarantor of its
obligations thereunder.

          "Legal Requirements" means all provisions of all laws, statutes,
           ------------------                                             
codes, acts, ordinances, orders, judgments, decrees, injunctions, rules,
regulations, directions and requirements of, restrictions by, and agreements
with, Federal, State or local governmental bodies, agencies or officials, now or
hereafter applicable to the Mortgaged Property or any part thereof or any use or
condition thereof.

          "Lenders" means those parties identified as a "Lender" on Annex 1
           -------                                                         
hereto.

          "Loss" is defined in Section 8.4.
           ----                            

          "Material Agreements" is defined in Granting Clause G.
           -------------------                                  

          "Mortgage" is defined in the Preamble.
           --------                             

          "Mortgaged Property" is defined in the Preamble to the Grant of Lien.
           ------------------                                                  

          "Mortgagee" means the Agent and the Lenders, or any of them, as the
           ---------                                                         
context may require.

          "Mortgagor" is defined in the Preamble.
           ---------                             

                                      -8-

 
          "Other Mortgaged Properties" means the Mortgaged Property described in
           --------------------------                                           
one or more of the Other Mortgages.

          "Other Mortgages" means those certain Mortgage, Security Agreement and
           ---------------                                                      
Assignment of Rents and Leases, if any, and those certain Deed of Trust,
Security Agreement and Assignment of Rents and Leases, if any, or other similar
agreements, granted from time to time by Mortgagor to Mortgagee concurrently
herewith or otherwise pursuant to the Credit Agreement with respect to
collateral not described in this Mortgage, as the same may hereafter be
modified, extended, replaced or otherwise amended.

          "Permits" is defined in Granting Clause L.
           -------                                  

          "Permitted Encumbrances" means those matters described on Exhibit C
           ----------------------                                            
hereto.

          "Personal Property" means all of the items described in the definition
           -----------------                                                    
of Mortgaged Property that constitute personal property under the Uniform
Commercial Code or other applicable law (including common law) of the State.

          "Property" is defined in Granting Clause B.
           --------                                  

          "Receiver" means any receiver, trustee liquidator, conservator,
           --------                                                      
custodian or similar Person.

          "Rents" are defined in Granting Clause H.
           -----                                   

          "Secured Obligations" means all of the Liabilities of Mortgagor to the
           -------------------                                                  
Mortgagee (or any of them) under and as defined in the Guarantee, including:

          (i)    all loans, advances, debts, liabilities, and other obligations
for monetary amounts (whether or not such amounts are liquidated, contingent or
otherwise determinable) owing by either Wahlco or Thermatrix or any of their
respective Subsidiaries or all of them to any Mortgagee, or any Subsidiary or
Affiliate of any Mortgagee, and all covenants, duties and obligations regarding
such amounts, of any kind or nature, present or future, whether or not evidenced
by any note, agreement or other instrument, arising under the Credit Agreement
or any of the other Loan Documents, whether at maturity or by prepayment,
acceleration, declaration of default or otherwise, including, without
limitation, the principal amount of the Loans, as well as all interest thereon
(including all amounts owed in respect of interest that accrues after the
commencement of any case, proceeding or other action relating to the bankruptcy,
insolvency or reorganization of any Loan Party), and all charges, costs,
expenses, attorneys' fees and any other sum chargeable to either Wahlco or
Thermatrix or any or all of their respective Subsidiaries under any of the Loan
Documents,

                                      -9-

 
          (ii)   all other amounts payable by Mortgagor hereunder (including all
amounts owed in respect of interest that accrues after the commencement of any
case, proceeding or other action relating to the bankruptcy, insolvency or
reorganization of any of Mortgagor, Wahlco or Thermatrix),

          (iii)  all Contingent Obligations of Mortgagor and all Future Advances
made to or for the account of Mortgagor, as set forth and referenced in Section
10.5 hereof, and

          (iv)   any renewals or extensions of any of the foregoing.

          "Security Agreement" means the Amended and Restated Security
           ------------------                                         
Agreement, dated as of the date hereof, among Wahlco Environmental Systems,
Inc., each Subsidiary party thereto and Wexford Management LLC.

          "Security Deposit Collateral" is defined in Granting Clause I.
           ---------------------------                                  

          "State" means the State of Maine.
           -----                           

          "Tangible Property" is defined in Granting Clause F.
           -----------------                                  

          "Thermatrix" is defined in Background Paragraph A.
           ----------                                       

          "Unavoidable Delays" means delays due to acts of God, governmental
           ------------------                                               
restrictions, enemy actions, civil commotion, fire, casualty, strikes, shortages
of supplies or labor or other causes beyond the reasonable control of Mortgagor,
but lack of funds shall not be a cause beyond the reasonable control of
Mortgagor.

          "Uniform Commercial Code" means the Uniform Commercial Code of the
           -----------------------                                          
State as in effect from time to time.

          "Unmatured Default" means an event which but for the lapse of time or
           -----------------                                                   
the giving of notice, or both, would constitute a Default or an Event of Default
hereunder or under any other Loan Document.

          "Wahlco" is defined in Background Paragraph A.
           ------                                       

          SECTION 1.3. Terms Defined in Uniform Commercial Code.  Unless
                       ----------------------------------------         
otherwise defined herein or in the Credit Agreement, or unless the context
otherwise requires, when used in this Mortgage, terms defined in the Uniform
Commercial Code have the same meanings.

          SECTION 1.4. Rules of Interpretation. In this Mortgage, unless
                       -----------------------                          
otherwise 

                                      -10-

 
specified, (i) singular words include the plural and plural words include the
singular, (ii) words that include a number of constituent parts, things or
elements, including the terms "Land", "Improvements," "Property" and "Mortgaged
Property" (and each element thereof) shall be construed as referring separately
to each constituent part, thing or element thereof, as well as to all of such
constituent parts, things or elements as a whole, (iii) words importing any
gender include the other gender, (iv) references to any Person include such
Person's successors and assigns and, in the case of an individual, the word
"successor" includes such Person's heirs, devisees, legatees, executors,
administrators and personal representatives, (v) references to any statute or
other law include all applicable rules, regulations and orders adopted or made
thereunder and all statutes or other laws amending, consolidating or replacing
the statute or law referred to, (vi) the words "include" and "including," and
words of similar import, shall be deemed to be followed by the words ", without
limitation," (vii) the words "hereto," "herein," "hereof," and "hereunder," and
words of similar import, refer to this Mortgage in its entirety, (viii) unless
otherwise specified, references to Articles, Sections, Exhibits, Schedules,
paragraphs and clauses are to the Articles, Sections, Exhibits, Schedules,
paragraphs and clauses of this Mortgage, (ix) the Exhibits and Schedules to this
Mortgage are incorporated herein by reference, (x) the titles and headings of
Articles, Sections, Exhibits, Schedules, paragraphs and clauses are inserted as
a matter of convenience and shall not affect the construction of this Mortgage
and (xi) unless otherwise specified, references to this Mortgage and to any
other Loan Document include all amendments, modifications, supplements,
consolidations, replacements, extensions and renewals thereof from time to time.

                                  ARTICLE II
                     Covenants and Agreements of Mortgagor

          To protect the security of this Mortgage, so long as this Mortgage is
in effect, Mortgagor further covenants and agrees with Mortgagee as follows:

          SECTION 2.1. Payment of Secured Obligations.  Mortgagor shall duly and
                       ------------------------------                           
punctually pay and perform all of the Secured Obligations in accordance with the
terms thereof and hereof, as if each of the same was set forth at length herein.

          SECTION 2.2. Further Assurances.  At the request of Mortgagee,
                       ------------------                               
Mortgagor shall, at Mortgagor's sole cost and expense (a) promptly correct any
defect or error which may be discovered in this Mortgage or any financing
statement or other document relating hereto, (b) promptly execute, acknowledge,
deliver, record and re-record, register and re-register, and file and re-file
this Mortgage and any financing statements or other documents or instruments
which Mortgagee may require from time to time, all in form and substance
reasonably satisfactory to Mortgagee, in order (i) to effectuate, complete,
perfect, continue or preserve the Lien and priority of this Mortgage as a
perfected mortgage lien and security interest on the Mortgaged Property, or (ii)
to effectuate, complete, perfect, continue or preserve any right, 

                                      -11-

 
power or privilege granted to Mortgagee hereunder, and (c) pay all filing,
registration and recording taxes, fees, dues, imposts, assessments and charges
in connection with the execution, delivery, filing, registration or recording of
any of the foregoing.

          SECTION 2.3. Care of the Mortgaged Property.
                       ------------------------------ 

          (a)  Operation and Maintenance.  Mortgagor (i) shall not cause or
               -------------------------                                   
permit the Mortgaged Property to be injured, wasted, disfigured or damaged or to
deteriorate (except for reasonable wear and tear and obsolescence) and (ii)
shall maintain and preserve all of the Mortgaged Property in good repair,
working order and condition (taking into consideration ordinary wear and tear)
and from time to time make, or cause to be made, all repairs, renewals and
replacements, betterments and improvements thereto reasonably necessary,
consistent with applicable industry practices, so that the business carried on
in connection therewith may be properly and advantageously conducted at all
times, in each case except to the extent that the failure to do so could not
reasonably be expected to have a Material Adverse Effect.

          (b)  Repair and Replacement.  Mortgagor shall not remove, demolish or
               ----------------------                                          
materially alter any of the Mortgaged Property.  Whether or not it shall have
received or otherwise be entitled to receive any Insurance Proceeds or
Condemnation Proceeds under the Credit Agreement, Mortgagor shall promptly
repair, replace and rebuild any part of the Mortgaged Property which may be
damaged or destroyed by any Casualty (including any casualty for which insurance
was not obtained or obtainable) or which may be affected by any Condemnation,
and shall complete and pay for, within a reasonable time, any structure at any
time in the process of construction or repair on the Property, all in a
commercially reasonable manner reasonably satisfactory to Mortgagee, unless the
failure to repair, replace or rebuild the same could not reasonably be expected
to have a Material Adverse Effect.

          (c)  Use.  Mortgagor shall not, without the prior written consent of
               ---                                                            
Mortgagee, which will not be unreasonably withheld, initiate, join in or consent
to any restrictive covenant, zoning ordinance, or other public or private
restrictions, limiting or defining the uses which may be made of the Property or
any part thereof.

          SECTION 2.4. Compliance With Laws and Payment of Impositions.
                       -----------------------------------------------  
Contests.  Except to the extent provided otherwise in the Credit Agreement,
- --------                                                                   
Mortgagor shall (i) at all times comply with, and shall cause the Mortgaged
Property at all times to comply with, all applicable Legal Requirements and
Insurance Requirements; and (ii) promptly pay all Impositions and all charges
for utilities and other services to the Mortgaged Property on or before the date
on which the same shall become due and payable.

          SECTION 2.5. Insurance and Casualty.
                       ---------------------- 

          (a) Required Insurance.  During the term of this Mortgage, Mortgagor
              ------------------                                              
shall 

                                      -12-

 
maintain, or cause to be maintained (including by one or more blanket and/or
umbrella policies which meet the requirements of this Section), the property and
liability insurance with respect to the Mortgaged Property described in Schedule
3(b) of the Disclosure Letter.

          (b)  Form.  All insurance required by this Mortgage shall be taken out
               ----                                                             
and maintained with an insurer, shall have such deductibles, and shall otherwise
be in form and substance, as required by the Credit Agreement.  In addition,
each such policy shall name Mortgagee as an additional insured and loss payee
and shall contain standard clauses waiving all rights of subrogation against
Mortgagee and requiring that all Insurance Proceeds resulting from any claim be
paid to Mortgagee, notwithstanding (i) any act or negligence of either Mortgagor
or its agents or employees which might, absent such agreement, result in a
forfeiture of all or part of such insurance payment, (ii) the occupation or use
of the Mortgaged Property or any part thereof for purposes more hazardous than
permitted by the terms of such policy, (iii) any foreclosure or other action or
proceeding taken pursuant to the Mortgage or (iv) any change in title to or
ownership of the Mortgaged Property or any part thereof.  Each policy shall
contain an undertaking by the insurer that such policy shall not be modified
without at least thirty (30) days' prior notice to, and the prior written
consent of, Mortgagee.

          (c)  Notice of Loss. If a Casualty occurs, Mortgagor shall immediately
               --------------
take such action or cause such action to be taken as may be reasonably necessary
or appropriate to protect the remaining Mortgaged Property.  Mortgagor will also
give Mortgagee prompt notice of any material damage to or destruction of any of
the Mortgaged Property and in case of loss covered by policies of insurance,
Mortgagee is hereby authorized to make proof of loss if not made promptly by
Mortgagor.  Any reasonable expenses incurred by Mortgagee in the collection of
the proceeds of such policies of insurance, together with interest thereon from
date of any such expense at the Overdue Rate (or such lesser rate of interest as
may be the maximum not prohibited by applicable law), shall be added to and
become part of the Secured Obligations and shall be reimbursed to Mortgagee
immediately upon demand.

          (d)  No Separate Insurance.  Mortgagor shall not take out separate
               ---------------------                                        
insurance concurrent in form or contributing in the event of loss with that
required to be maintained hereunder unless Mortgagee is named as an additional
insured thereon under a standard mortgagee clause reasonably acceptable to
Mortgagee and each such policy is otherwise in form and substance reasonably
acceptable to Mortgagee.  Mortgagor shall notify Mortgagee at least 30 days
prior to the date that any such separate insurance is to be taken out and, if
such insurance is permitted by Mortgagee, shall promptly deliver to Mortgagee a
copy of the policy or policies of such insurance.

          (e)  Assignment of Policies On Foreclosure.  In the event of the
               -------------------------------------                      
foreclosure of this Mortgage, or other transfer of title to the Mortgaged
Property, or any part thereof, by foreclosure sale, or by power of sale, or deed
in lieu of foreclosure, the purchaser of the Mortgaged Property, or such part
thereof, shall succeed to all of each Mortgagor's rights with 

                                      -13-

 
respect to the Mortgaged Property, including any rights to unexpired, unearned
or returnable insurance premiums, subject to limitations on the assignment of
blanket policies, but limited to such rights as relate to the Mortgaged Property
or such part thereof. If Mortgagee acquires title to the Mortgaged Property, or
any part thereof, in any manner, it shall thereupon (as between each Mortgagor
and Mortgagee) become the sole and absolute owner of the insurance policies, and
all proceeds payable thereunder with respect to the Mortgaged Property with the
sole right to collect and retain all unearned or returnable premiums thereon
with respect to the Mortgaged Property, or such part thereof, if any.

          SECTION 2.6.  Condemnation.
                        ------------ 

          (a)  Notice of Loss.  In the event of any Condemnation or the
               --------------                                          
commencement of any proceedings or negotiations that might result in a
Condemnation, Mortgagor shall give notice thereof to Mortgagee, generally
describing the nature and extent of such Condemnation or the nature of such
proceedings or negotiations and the nature and extent of the proposed
Condemnation, as the case may be.

          (b)  Protection of Mortgaged Property.  If a Condemnation occurs,
               --------------------------------                            
Mortgagor shall immediately take such action or cause such action to be taken as
may be reasonably necessary or appropriate to protect the remaining Mortgaged
Property.

          SECTION 2.7.  Application of Insurance Proceeds and Condemnation
                        --------------------------------------------------
Proceeds.
- -------- 

          (a)  Proceeds Payable to Mortgagee.  Notwithstanding any Casualty or
               -----------------------------                                  
Condemnation, Mortgagor shall continue to pay the Secured Obligations at the
time and in the manner provided for in the Loan Documents and this Mortgage, and
the Secured Obligations shall not be reduced until any Insurance Proceeds or
Condemnation Proceeds shall have been actually received and applied by Mortgagee
to the discharge of the Secured Obligations.  Except as expressly provided in
the Credit Agreement, Mortgagee may apply the entire amount of any Insurance
Proceeds or Condemnation Proceeds to the discharge of the Secured Obligations
whether or not then due and payable in such priority and proportions as
Mortgagee in its discretion shall deem proper.  If the Mortgaged Property is
sold, through foreclosure or otherwise, prior to the receipt by Mortgagee of
such Insurance Proceeds or Condemnation Proceeds, Mortgagee shall have the
right, whether or not a deficiency judgment on any Loan Document shall have been
sought, recovered or denied, to receive such Insurance Proceeds or Condemnation
Proceeds, or a portion thereof sufficient to pay the Secured Obligations,
whichever is less.

                                      -14-

 
          (b)  Prosecution of Claim for Loss.  If a Casualty or a Condemnation
               -----------------------------                                  
shall occur, Mortgagor shall file and prosecute its claim or claims for any such
Insurance Proceeds or Condemnation Proceeds in good faith and with due diligence
and cause the same to be collected and paid over to Mortgagee, and hereby
irrevocably authorizes and empowers Mortgagee, in the name of Mortgagor or
otherwise to collect and receipt for any such Insurance Proceeds or Condemnation
Proceeds and to adjust any insurance claims and to file and prosecute such claim
or claims, and although it is hereby expressly agreed that the same shall not be
necessary in any event, Mortgagor shall, upon demand of Mortgagee, make, execute
and deliver any and all assignments and other instruments sufficient for the
purpose of assigning any such Insurance Proceeds or Condemnation Proceeds to
Mortgagee, free and clear of any Liens whatsoever.  Mortgagor hereby irrevocably
appoints Mortgagee as Mortgagor's attorney-in-fact for each such purpose (which
appointment is coupled with an interest) and authorizes any Person to act upon
the foregoing appointment.

          SECTION 2.8.  Transfer Restrictions.  Except as expressly permitted by
                        ---------------------                                   
the Credit Agreement, Mortgagor shall not further mortgage, hypothecate, pledge
or suffer to exist any Lien on, or sell, transfer, convey or lease, all or any
part of the Mortgaged Property (or any interest therein).

          SECTION 2.9.  Mortgagee's Right to Perform. If Mortgagor shall fail to
                        ----------------------------                            
pay or perform any of the Secured Obligations, then Mortgagee, upon ten (10)
days' prior notice to Mortgagor may, but shall not be obligated to, make (or
cause to be made) any such payment or perform (or cause to be performed) any
such Secured Obligation of Mortgagor, in any form and manner deemed reasonably
appropriate by Mortgagee as agent or attorney-in-fact of Mortgagor, and any
amount so paid or extended, plus reimbursement to Mortgagee for its reasonable
out-of-pocket and other expenses, including legal expenses, for each matter for
which it acts under this Mortgage, shall be added to the Secured Obligations and
shall be repaid to Mortgagee upon demand.  By way of illustration and not in
limitation of the foregoing, Mortgagee may, but need not, make payments of
principal, interest or other charges on any obligations secured by any Permitted
Encumbrance or other Lien or charge; purchase, discharge, compromise or settle
any tax Lien or any other Lien, encumbrance, suit, proceeding, title or claim
thereof; pay any premium owing on any insurance policy covering the Mortgaged
Property; or redeem from any tax sale or forfeiture affecting the Property or
contest any tax or assessment.  In making any payment or securing any
performance relating to any such obligation of Mortgagor hereunder or
thereunder, Mortgagee, so long as it acts in good faith, shall be the sole judge
of the legality, validity and amount of any Lien or encumbrance and of all other
matters necessary to be determined in satisfaction thereof.  No such action of
Mortgagee shall be considered as a waiver of any right accruing to it on account
of the occurrence of any default on the part of Mortgagor under this Mortgage,
any Event of Default or any default or event of default under any other Loan
Document.

          SECTION 2.10. Subrogation. To the extent that Mortgagee, after the
                        -----------                                         
date 

                                      -15-

 
hereof, pays pursuant to the terms of this Mortgage, the Credit Agreement or any
other Loan Document any sum due under any provision of law or any instrument or
document creating any Lien prior or superior to the Lien of this Mortgage,
Mortgagee shall have and be entitled to a Lien on the Mortgaged Property equal
in priority to that discharged, and Mortgagee shall be subrogated to, and
receive and enjoy all rights and Liens possessed, held or enjoyed by the holder
of such Lien, which shall remain in existence for the benefit of Mortgagee to
secure the amount expended by Mortgagee on account of or in connection with such
Lien. Mortgagee shall be subrogated, notwithstanding their release of record, to
mortgages, trust deeds, superior titles, vendor's Liens, Liens, charges,
encumbrances, rights and equities on the Property to the extent that any
obligation under any thereof is paid or discharged by Mortgagee.

          SECTION 2.11.  Inspection of Mortgaged Property.  Mortgagor shall
                         --------------------------------                  
permit Mortgagee and Mortgagee's agents, as frequently as Mortgagee reasonably
determines to be appropriate, during normal business hours (or at such other
times as may be reasonably be requested by Mortgagee), to enter upon the
Property for the purpose of inspecting and/or appraising the Mortgaged Property
and all books, records and documents of Mortgagor relating thereto, and for the
purpose of performing any of the acts that Mortgagee is authorized to perform
under the terms of any of the Loan Documents; provided, that Mortgagee shall
                                              --------                      
have no duty to make such inspections and shall not incur any liability or
obligation for making or not making inspections.  In exercising the foregoing
rights, Mortgagee shall use reasonable efforts to minimize any disruption of
Mortgagor's operations and shall be subject to Mortgagor's reasonable security
and operating measures.

          SECTION 2.12.  Certain Tax Law Changes. In the event of the passage
                         -----------------------                             
after the date of this Mortgage of any law deducting from the value of real
property, for the purpose of taxation, amounts in respect of any lien thereon or
changing in any way the laws for the taxation of mortgages or debts secured by
mortgages for state or local purposes or the manner of the collection of any
such taxes, and in any such event imposing a tax, either directly or indirectly,
on this Mortgage, Mortgagor shall pay such tax on or before the later of the
date the same is due and the tenth day after Mortgagor obtains actual knowledge
of the same.

          SECTION 2.13.  Future Advances.  All future advances under this
                         ---------------                                 
Mortgage or under any other agreements at any time made between Mortgagor and
Mortgagee shall have the same priority as if the future advance was made on the
date that this Mortgage was recorded.  Notice is hereby given that the Secured
Obligations may increase as a result of any defaults hereunder by Mortgagor due
to, for example, and without limitation, unpaid interest or late charges, unpaid
Impositions or insurance premiums or other charges which Mortgagee elects to
advance, defaults under Leases that Mortgagee elects to cure, attorneys' fees or
costs incurred in enforcing the Loan Documents or other expenses.  Except as
otherwise provided in the Credit Agreement, interest shall be payable on any
future advances at the Overdue Rate.

                                      -16-

 
          SECTION 2.14.  Covenants in Loan Documents.  Mortgagor shall also
                         ---------------------------                       
comply with all other covenants and obligations (a) which either Wahlco or
Thermatrix is obligated under the Credit Agreement to cause Mortgagor to comply
with, and (b) set forth in the Security Agreement, as if each of the same was
set forth at length herein as the direct obligation of Mortgagor hereunder.


                                  ARTICLE III
                         Representations and Warranties

          Mortgagor represents and warrants to and agrees with the Secured
Parties as follows:

          SECTION 3.1.

          (a)  Title.  Mortgagor owns and will at all times own good and
               -----                                                    
marketable fee simple title to the Property, and good and valid title to the
balance of the Mortgaged Property, in each case free and clear of all Liens,
other than the Lien and security interests created by this Mortgage and any
Permitted Encumbrances.

          (b)  Chain of Title.  Mortgagor acquired title to the Property under
               --------------                                                 
the name Bachman Properties, Inc.  Bachman Properties, Inc. merged into and with
Bachman Industries, Inc. on or about June, 28, 1990.  Bachman Industries Inc.
                                     --------------                          
thereafter changed its name to Wahlco Engineered Products, Inc.

          SECTION 3.2.  Valid Lien and Security Interest.  This Mortgage creates
                        -------------------------------                         
(a) a valid and enforceable lien on the Property under the laws of the State in
favor of Mortgagee as security for the Secured Obligations, and (b) a valid and
enforceable security interest in the Personal Property under the laws of the
State in favor of Mortgagee as security for the Secured Obligations.  All
necessary actions have been taken to establish a duly perfected first priority
lien and security interest in favor of Mortgagee in respect of Mortgagor's
interest in the Mortgaged Property (other than only the recording of this
Mortgage in the appropriate land records therefor), including, if required under
State law, the filing of record of financing statements in the appropriate form,
properly describing the Personal Property, duly executed by Mortgagor, in the
offices listed on Exhibit D hereto and the payment of all taxes and filing fees
                  ---------                                                    
in connection therewith.  The description of the Personal Property set forth in
such financing statements is sufficient to perfect a security interest in those
items of Personal Property in which a security interest may be perfected by the
filing of a financing statement under the Uniform Commercial Code.  No further
or subsequent filing, refiling, recording, rerecording, registration or
reregistration is necessary, except as provided under applicable law with
respect to the filing of continuation statements.  No mortgage, deed of trust or
similar instrument and no financing statement or other similar document has been
signed, recorded or 

                                      -17-

 
filed covering Mortgagor's right, title or interest in or to any Mortgaged
Property, other than (a) those naming Mortgagee as mortgagee or secured party
thereunder and (b) those creating Permitted Encumbrances.


                                  ARTICLE IV
                     Security Agreement and Fixture Filing

          SECTION 4.1.  Security Agreement.
                        ------------------ 

          (a)  Grant of Security Interest.  To the extent that the Mortgaged
               --------------------------                                   
Property includes Personal Property under applicable State law, this Mortgage
shall also be construed as a security agreement and the grant to the Mortgagee,
of a security interest in such Personal Property under the Uniform Commercial
Code.

          (b)  Remedies.  If an Event of Default shall occur, Mortgagee may
               --------                                                    
exercise from time to time and at any time any rights and remedies available to
it under applicable law upon default in the payment of indebtedness, including,
without limitation, any right or remedy available to it as a secured party under
the Uniform Commercial Code.  Mortgagor shall, promptly upon request by
Mortgagee, assemble the Mortgaged Property, or any portion thereof generally
described in such request, and make the same available to Mortgagee at such
place or places designated by Mortgagee and reasonably convenient to Mortgagee
and Mortgagor.  If Mortgagee elects to proceed under the Uniform Commercial Code
to dispose of all or any portion of the Mortgaged Property, Mortgagee, at its
option, may give Mortgagor notice of the time and place of any public sale of
any such property, or of the date after which any  sale or other disposition
thereof is to be made, by sending notice by registered or certified first class
mail, postage prepaid, to Mortgagor at least ten (10) days prior to the time of
the sale or other disposition.  If any notice of any proposed sale, assignment
or transfer by Mortgagee of any portion of the Collateral or any interest
therein is required by law, Mortgagor conclusively agrees that, unless any
longer period shall then be required by the Uniform Commercial Code, ten (10)
days' notice to Mortgagor of the date, time and place (and, in the case of a
sale, the terms) thereof is reasonable.  Mortgagee may, at its option, appoint
any other Person as the agent of Mortgagee for the purpose of disposition of the
Personal Property in accordance with the Uniform Commercial Code.  Mortgagor
acknowledges and agrees that a disposition of the Personal Property in
accordance with Mortgagee's rights and remedies in respect of the Personal
Property as provided in this Section is a commercially reasonable disposition
thereof.

          SECTION 4.2.  Fixture Filing.  To the extent that the Mortgaged
                        --------------                                   
Property includes items of Personal Property that are or are to become fixtures
under applicable law, and to the extent permitted under applicable law, the
filing of this Mortgage in the land records of the county in which such
Mortgaged Property is located shall also operate from the time of 

                                      -18-

 
fixture filing with respect to such Mortgaged Property, the information required
for the purpose of such fixture filing being as set forth in this Mortgage.

          SECTION 4.3.  Security Deposit Collateral.  So long as no Event of
                        ---------------------------                         
Default shall have occurred and shall be continuing, Mortgagor shall have the
exclusive right, as between Mortgagor and Mortgagee, to apply, draw, make
demand, sue for, or amend any Security Deposit Collateral or waive or release
any party from its obligations under or in respect of any Security Deposit
Collateral.  If an Event of Default shall occur and shall be continuing,
Mortgagee shall (at its option) have the exclusive right, as between Mortgagor
and Mortgagee, upon notice to Mortgagor, to apply, draw, make demand, sue for,
or amend any Security Deposit Collateral.

          SECTION 4.4.  Additional Covenants.  All other covenants and
                        --------------------                          
obligations of Mortgagor contained herein relating to the Mortgaged Property
(including those incorporated by reference under Section 2.14 hereof) shall be
deemed to apply to the Personal Property whether or not expressly referred to in
this Article IV, as if the same were the direct obligation of Mortgagor set
forth at length herein.


                                   ARTICLE V
                        Assignments of Rents and Leases

          SECTION 5.1.  Assignment of Rents and Leases.
                        ------------------------------ 

          (a)  Assignment of Rents.  Mortgagor hereby presently, absolutely and
               -------------------                                             
irrevocably assigns to Mortgagee, subject to the license of Mortgagor under
subsection (b) of this Section, all Leases and the Rents, and Mortgagee and, if
a Receiver has been appointed under this Mortgage, such Receiver, shall have the
absolute, immediate and continuing right, subject to mandatory provisions of
applicable law, to collect and receive all Rents now or hereafter, including
during any period of redemption, accruing with respect to the Property.  The
Lien on the Leases and the Rents made under Granting Clause H hereof shall be in
addition to and subject to the foregoing assignment.  At the request of
Mortgagee or such Receiver, Mortgagor shall promptly execute, acknowledge,
deliver, record, register and file any additional general assignment of the
Leases or specific assignment of any Lease which Mortgagee or such Receiver may
require from time to time (all in form and substance reasonably satisfactory to
Mortgagee and such Receiver) to effectuate, complete, perfect, continue or
preserve this assignment of the Leases and the Rents and the Lien upon the
Leases and the Rents made under Granting Clause H.

          (b)  License to Collect Rents.  As long as no Event of Default has
               ------------------------                                     
occurred, Mortgagor shall have the right under a license granted hereby, subject
to subsection (c) of this Section, to collect the Rents upon the due date
thereof, but not prior to such due date.

                                      -19-

 
          (c)  Termination of License Upon Event of Default.  If an Event of
               --------------------------------------------                 
Default shall occur, the license granted under subsection (b) of this Section
shall immediately and automatically terminate, without the necessity of any
action by any Person, and Mortgagee and any Receiver appointed under this
Mortgage shall have the right to exercise the rights and remedies provided under
this Mortgage or otherwise under applicable law.  If an Event of Default shall
occur, upon demand by the Person exercising the rights under this Section,
Mortgagor shall promptly pay to such Person all security deposits under the
Leases and all Rents allocable to any period after the occurrence of such Event
of Default.  Subject to any applicable Legal Requirement, any Rents received
hereunder by the Person exercising the rights under this Section shall be
promptly paid to Mortgagee, and any Rents received hereunder by Mortgagee shall
be applied and disbursed as provided in Section 6.9; provided that, subject to
any applicable requirement of law, any security deposits actually received by
Mortgagee shall be held, applied and disbursed as provided in the applicable
Leases.

          (d)  Direction to Tenants. Upon the occurrence of an Event of Default,
               --------------------
Mortgagor shall, at the direction of Mortgagee, further authorize and direct, in
writing, the tenant under each Lease to pay directly to, or as directed by,
Mortgagee all Rents accruing or due under its Lease without proof to the tenant
of the occurrence and continuance of such Event of Default. Mortgagor hereby
authorizes the tenant under each Lease to rely upon and comply with any notice
or demand from Mortgagee for payment of Rents to Mortgagee and Mortgagor shall
have no claim against any tenant for Rents paid by such tenant to Mortgagee
pursuant to such notice or demand.

          (e)  No Release of Tenants.  Neither this Mortgage nor any action or
               ---------------------                                          
inaction on the part of Mortgagee shall release any tenant under any lease, any
guarantor of any Lease or Mortgagor from any of their respective obligations
under the Leases or constitute an assumption of any such obligation on the part
of Mortgagee.  No action or failure to act on the part of Mortgagor shall
adversely affect or limit the rights of Mortgagee under this Mortgage or,
through this Mortgage, under the Leases.

          (f)  No Liability of Mortgagee.  Neither the acceptance hereof nor the
               -------------------------                                        
exercise of the rights and remedies hereunder nor any other action on the part
of Mortgagee or any Person exercising the rights of Mortgagee hereunder shall be
construed to (i) be an assumption by Mortgagee or any such Person or to
otherwise make Mortgagee or such Person liable or responsible for the
performance of any of the obligations of Mortgagor under or with respect to the
Leases or for any Rent, security deposit or other amount delivered to Mortgagor;
provided that Mortgagee or any such Person exercising the rights of Mortgagee
shall be accountable as provided in subsection (c) of this Section for any
Rents, security deposits or other amounts actually received by Mortgagee or such
Person, as the case may be; or (ii) obligate Mortgagee or any such Person to
take any action under or with respect to the Leases or with respect to the
Mortgaged Property, to incur any expense or perform or discharge any 

                                      -20-

 
duty or obligation under or with respect to the Leases or with respect to the
Mortgaged Property, to appear in or defend any action or proceeding relating to
the Leases or the Mortgaged Property, to constitute Mortgagee as a mortgagee in
possession (unless Mortgagee actually enters and takes possession of the
Mortgaged Property), or to be liable in any way for any injury or damage to
person or property sustained by any Person in or about the Mortgaged Property,
other than to the extent caused by the willful misconduct or gross negligence of
Mortgagee or any Person exercising the rights of Mortgagee hereunder.

          (g)  No Existing Leases.  Mortgagor represents and warrants that as of
               ------------------                                               
the date hereof, no Leases exist with respect to the Mortgaged Property.


                                   ARTICLE VI
                             Defaults and Remedies

          SECTION 6.1.  Events of Defaults.  The following shall be an Event of
                        ------------------                                     
Default hereunder (an "Event of Default"):  any Event of Default by or with
                       ----------------                                    
respect to Mortgagor, either Borrower or any other Loan Party under and as
defined in the Credit Agreement or any other Loan Document.


          SECTION 6.2.  Remedies.
                        -------- 

          (a)  General.  If an Event of Default shall occur and shall be
               -------                                                  
continuing, Mortgagee, with or without entry onto the Property, shall have the
following rights:

                    (i)    to immediately foreclose this Mortgage and the lien
     hereof;

                    (ii)   to sell Mortgagor's right, title and interest in and
     to the Mortgaged Property, as a whole or in separate parcels, at one or
     more public sales, at such time and place and upon such terms and
     conditions as may be required or permitted by applicable law. Such power
     shall not be exhausted until the Secured Obligations have been paid in
     full. Mortgagee may execute and deliver to the purchaser or purchasers at
     any sale a sufficient conveyance of the Mortgaged Property sold thereby
     divesting Mortgagor of all right, title or interest that it may have in and
     to such Mortgaged Property and vesting the same in the purchaser or
     purchasers at such sale or sales, free of the security interest and lien of
     this Mortgage and free of all rights of redemption in Mortgagor;

                    (iii)  to take such steps to protect and enforce its rights
     and the lien of this Mortgage whether by action, suit or proceeding in
     equity or at law for the

                                      -21-

 
     specific performance of any provision in the Loan Documents, or in aid of
     the execution of any power granted in this Mortgage, or for any foreclosure
     hereunder, or for the enforcement of any other appropriate legal or
     equitable remedy Mortgagee shall elect;

                    (iv)   to apply for the appointment of a Receiver for the
     Mortgaged Property in accordance with Section 6.4; and

                    (v)    to take all such other steps and to assert and
     exercise all such other rights and remedies as shall be permitted by
     applicable law.

          (b)  Foreclosure.  This Mortgage may be foreclosed once against all or
               -----------                                                      
successively against any part or parts of the Mortgaged Property as Mortgagee
may elect.  This Mortgage and the right of foreclosure hereunder shall not be
impaired or exhausted by one or any foreclosure or by one or any sale, and may
be  foreclosed successively and in parts, until all of the Mortgaged Property
has been foreclosed against and sold.  The purchase money proceeds or avails of
any foreclosure or sale after default and any other sums which then may be held
by Mortgagee under this Mortgage shall be applied as provided in Section 6.9
hereof.

          (c)  Mortgagee May Bid.  In connection with any such foreclosure or
               -----------------                                             
sale, Mortgagee may bid for and acquire Mortgagor's interest in the Mortgaged
Property or any part thereof and in lieu of paying cash therefor, may make
settlement for the purchase price by crediting upon the Secured Obligations the
net sale price after deducting therefrom the amounts referred to in clause
"first" of Section 6.9.  Mortgagee may adjourn from time to time any sale by it
to be made under or by virtue of this Mortgage by announcement at the time and
place appointed for such sale or for such adjourned sale or sales, and,
Mortgagee, without further notice or publication, may make such sale at the time
and place to which the same shall be so adjourned.

          (d)  Acceleration of Secured Obligations.  In the event of any sale
               -----------------------------------                           
made under or by virtue of this Article, the entire principal of, interest and
other amounts in respect of the Secured Obligations, if not previously due and
payable, shall, at the option of Mortgagee, immediately become due and payable,
anything in this Mortgage to the contrary notwithstanding.

                                      -22-

 
          SECTION 6.3.  Possession of Property.
                        ---------------------- 

          (a)  Mortgagor to Vacate Property.  Mortgagor hereby waives, if an
               ----------------------------                                 
Event of Default shall occur and shall be continuing, all right to the
possession and Rents of the Property, and Mortgagor hereby expressly authorizes
and empowers Mortgagee, upon such occurrence and continuation, for the purpose
of protecting and preserving the Property and the interest of Mortgagee therein,
and to the extent permitted by law, (i) to enter upon and take possession of the
Property, to remove and exclude Mortgagor and its agents and servants wholly
therefrom, by summary proceeding, ejectment or other legal proceeding, and to
take possession of all books, records and accounts relating thereto, and
Mortgagor agrees to surrender possession of the Property and of such books,
records and accounts to Mortgagee on demand and (ii) with or without the entry
upon or taking possession of the Property, to hold, operate, manage, repair and
maintain the Mortgaged Property and to collect and receive all Rents derived
from the Property, and after deducting therefrom all reasonable costs, expenses
and liabilities (including reasonable attorneys' fees and expenses) incurred by
Mortgagee in collecting the same and in using, managing, preserving and
controlling the Property for the purpose of protecting and preserving the
Mortgaged Property and the interest of Mortgagee therein, and otherwise in
exercising Mortgagee's rights hereunder, including all amounts necessary to pay
Impositions and reasonable other charges in connection with the Property, as
well as reasonable compensation for Mortgagee's agents and employees, and to
apply the remainder as set forth in Section 6.9.  Without limiting any other
right or remedy of Mortgagee pursuant to any other provision of this Mortgage or
the Credit Agreement, upon or at any time after the filing of a suit to
foreclose this Mortgage, the court in which such suit is filed shall have full
power to enter an order placing Mortgagee in possession of the Property with the
same power granted to a Receiver pursuant to the applicable Sections of this
Mortgage and with all other rights and privileges of a mortgagee-in-possession
under applicable State law.  All such costs, expenses and liabilities incurred
by Mortgagee shall be Secured Obligations.

          (b)  Payment for Use and Occupancy.  Following an Event of Default and
               -----------------------------                                    
the exercise by Mortgagee of its remedies hereunder, if at any time Mortgagee
shall have (and shall exercise) the right, following such summary proceeding,
ejectment or other proceeding pursuant to Section 6.3(a), to exclude Mortgagor
from all or any part of the Property and Mortgagor shall fail to vacate all or
such portion of the Property, then, Mortgagor shall pay the fair and reasonable
rental value for the use and occupancy of the Property or any portion thereof
that is being occupied by Mortgagor for such period and, upon default of any
such payment Mortgagor may be evicted by any summary action or proceeding for
the recovery of possession of such portion of the Property for nonpayment of
rent, however designated.

                                      -23-

 
          SECTION 6.4.  Appointment of Receiver.  If an Event of Default shall
                        -----------------------                               
occur and shall be continuing, Mortgagee shall, to the fullest extent permitted
by law, and without regard to the adequacy or value of any security for the
Secured Obligations or the solvency of Mortgagor, or the occupancy of the
Property or any part thereof as a homestead, and without the requirement of any
bond, be entitled to the appointment of a Receiver for all or any part of the
Mortgaged Property and all Rents therefrom (the inclusion in this Mortgage of
the provisions for the appointment of a Receiver and the assignment of Rents
being an express condition upon which Mortgagee agreed to execute the Credit
Agreement and to accept this Mortgage), whether or not such receivership is
incidental to a proposed sale of the Mortgaged Property or otherwise, and, to
the fullest extent permitted by law, Mortgagor hereby consents to the
appointment of such a Receiver and will not oppose any such appointment.

          SECTION 6.5.  Waiver of Stay, Extension, Moratorium and Marshalling
                        -----------------------------------------------------
Laws and Equity of Redemption.  To the maximum extent permitted by law,
- -----------------------------                                          
Mortgagor shall not at any time insist upon, or plead, or in any manner whatever
claim or take any benefit or advantage of any applicable present or future stay,
extension or moratorium law, which may affect observance or performance of the
provisions of this Mortgage; nor claim, take or insist upon any benefit or
advantage of any present or future law providing for the valuation or appraisal
of, or rights of marshalling with respect to, the Mortgaged Property or any
portion thereof prior to or in connection with any sale or sales thereof which
may be made under or by virtue of this Mortgage; and Mortgagor, to the extent
that it lawfully may, hereby waives all benefit or advantage of any such law or
laws.  Mortgagor, for itself and all who may claim under it, hereby waives, to
the maximum extent permitted by applicable law, any and all rights and equities
of redemption from sale under the power of sale created hereunder or from sale
under any order or decree of foreclosure of this Mortgage and (if an Event of
Default shall occur) all notice or notices of seizure, and all right to have the
Mortgaged Property marshalled upon any foreclosure hereof.  Mortgagee shall not
be obligated to pursue or exhaust its rights or remedies as against any other
part of the Mortgaged Property and Mortgagor hereby waives any right or claim of
right to have Mortgagee proceed against any portion of the Mortgage Property in
any particular order.

          SECTION 6.6.  Mortgagee Authorized to Execute Documents.  Mortgagor
                        -----------------------------------------            
irrevocably appoints Mortgagee the true and lawful attorney of Mortgagor (which
appointment is coupled with an interest and shall be irrevocable), in its name
and stead and on its behalf, for the purpose of effectuating any sale,
assignment, transfer or delivery for the enforcement hereof, whether pursuant to
power of sale, foreclosure or otherwise, to execute and deliver all deeds, bills
of sale, assignments, releases and other instruments as Mortgagee may consider
necessary or appropriate, with full power of substitution, Mortgagor hereby
ratifying and confirming all that its said attorney or any substitute shall
lawfully do by virtue hereof.  Nevertheless, if so requested by Mortgagee or any
purchaser, Mortgagor will immediately ratify and confirm, without any cost or
charge therefor, any such sale, assignment, transfer or delivery by executing
and delivering to the grantee or such purchaser all such proper deeds, 

                                      -24-

 
bills of sale, assignments, releases and other instruments as may be designated
in any such request.

          SECTION 6.7.  Collateral Situated in More than One County.  If the
                        -------------------------------------------         
Mortgaged Property is situated in two or more counties in the State, or in two
judicial districts of the same county, Mortgagee shall have the full power to
select in which county or counties, or in which judicial district or districts,
the sale of the Mortgaged Property is to be made, and Mortgagee's selection
shall be binding upon Mortgagor and shall permit the sale of the whole to be
made in any of the counties or judicial districts in which part of the Mortgaged
Property is located.  Mortgagor hereby waives any right it might otherwise have
or assert to object to foreclosure, through the use of a single Mortgage, upon
all of the Mortgaged Property in the State.

          SECTION 6.8.  Collateral in Other States.  Mortgagor acknowledges and
                        --------------------------                             
agrees that the Other Mortgaged Properties may be located in states other than
the State, and Mortgagor therefore waives and relinquishes any and all rights it
may have, whether at law or equity, to require Mortgagee to proceed to enforce
or exercise any rights, powers and remedies that Mortgagee or any trustee may
have under this Mortgage and the Other Mortgages in any particular manner, in
any particular order, or in any particular state or other jurisdiction.  Without
limiting the generality of the foregoing, (a) Mortgagee shall not be precluded
from or restricted in exercising any of its rights and remedies hereunder due to
the prior or concurrent exercise by Mortgagee or any trustee of any of its
rights and remedies under any Other Mortgage, (b) neither Mortgagee nor any
trustee shall be precluded from or restricted in exercising any of its rights
and remedies under any Other Mortgage due to the prior or concurrent exercise by
Mortgagee of any of its rights and remedies hereunder, and (c) neither Mortgagee
nor any trustee shall be required to exercise or enforce any of its rights and
remedies under any Other Mortgage before or concurrently with the exercise by
Mortgagee of any of its rights and remedies hereunder.  Mortgagor further agrees
that any particular proceeding, including foreclosure through court action (in a
state or federal court) or power of sale, may be brought and prosecuted in the
local or federal courts of any one or more of the states in which any of the
Mortgaged Property and the Other Mortgaged Properties may be located, without
regard to the fact that any one or more prior or contemporaneous proceedings
have been instituted elsewhere with respect to the same or any other portion of
the Mortgaged Properties or the Other Mortgaged Properties.

          SECTION 6.9.  Application of Proceeds.  Following the occurrence of an
                        -----------------------                                 
Event of Default, any proceeds of any of the Mortgaged Property shall be applied

          first, to the costs and expenses of the Mortgagees payable pursuant to
          -----                                                                 
     the Credit Agreement and this Mortgage,

          second, to the payment of all other Secured Obligations other than
          ------                                                            
     principal and 

                                      -25-

 
     interest,

          third, to interest accrued and unpaid on the Secured Obligations, on a
          -----                                                                 
     pro rata basis among the Mortgagees determined by the amount of interest
     accrued and unpaid on the Secured Obligations of each Mortgagee,

          fourth, to the satisfaction of the principal amount of the Secured
          ------                                                            
     Obligations, on a pro rata basis among the Mortgagees determined by
     principal amount of the Secured Obligations of each Mortgagee then
     outstanding, and

          fifth, the remainder, if any, to Mortgagor or such other Person as may
          -----                                                                 
     entitled thereto by law.

Mortgagor shall remain liable for any deficiency.

          SECTION 6.10.  Setoff.  To the fullest extent permitted by applicable
                         ------                                                
law, at any time while an Event of Default has occurred and is continuing, any
and all deposits (including all account balances, whether provisional or final
and whether or not collected or available) and any other Secured Obligations at
any time held or owing by the Mortgagees  to or for the credit or account of
Mortgagor, except accounts with respect to which Mortgagor is a trustee or an
escrow agent in respect of bona fide third parties, may be offset and applied
toward the payment of the Secured Obligations owing to such Mortgagee, whether
or not the Secured Obligations, or any part thereof, shall then be due.

          SECTION 6.11.  Receipt a Sufficient Discharge to Purchaser.  Upon any
                         -------------------------------------------           
sale of the Mortgaged Property or any part thereof or any interest therein,
whether pursuant to power of sale, foreclosure or otherwise, the receipt by
Mortgagee or the officer making the sale under judicial proceedings of the
purchase money therefor shall be a sufficient discharge to the purchaser for
such purchase money, and such purchaser shall not be obligated to see to the
application thereof.

          SECTION 6.12.  Sale a Bar Against Mortgagor.  Any sale of the
                         ----------------------------                  
Mortgaged Property or any part thereof or any interest therein under or by
virtue of this Mortgage, whether pursuant to power of sale, foreclosure or
otherwise, shall forever be a bar against Mortgagor.

          SECTION 6.13.  Remedies Cumulative; Waiver.  No remedy or right of
                         ---------------------------                        
Mortgagee hereunder, under the Credit Agreement, or any other Loan Document or
otherwise, or available under applicable law, shall be exclusive of any other
right or remedy, but each such remedy or right shall be in addition to every
other remedy or right now or hereafter existing at law or in equity under any
such document or under applicable law.  No delay in the exercise of, or omission
to exercise, any remedy or right accruing on any default or Event of 

                                      -26-

 
Default shall impair any such remedy or right or be construed to be a waiver of
any such default or Event of Default or an acquiescence therein, nor shall it
affect any subsequent default or Event of Default of the same or a different
nature. Every such remedy or right may be exercised concurrently or
independently, and when and as often as may be deemed proper by Mortgagee. All
obligations of Mortgagor, and all rights, powers and remedies of Mortgagee
expressed herein, shall be in addition to, and not in limitation of, those
provided by law or in the Credit Agreement, any other Loan Document or any other
written instrument relating to any of the Secured Obligations or any security
therefor. Any and all covenants of Mortgagor in this Mortgage may from time to
time, by instrument in writing signed by Mortgagee, be waived to such extent and
in such manner as Mortgagee may desire, but no such waiver will ever affect or
impair the rights of Mortgagee hereunder, except to the extent specifically
stated in such written instrument.

          SECTION 6.14.  No Liability of Mortgagees.  Notwithstanding anything
                         --------------------------                           
contained in this Mortgage, this Mortgage is only intended as security for the
Secured Obligations and the Mortgagees shall not be obligated to perform or
discharge, and does not hereby undertake to perform or discharge, any
obligation, duty or liability of Mortgagor with respect to any of the Mortgaged
Property.  Unless and until a Mortgagee takes actual possession of the Mortgaged
Property, either through foreclosure, the taking of a deed in lieu thereof or
otherwise, the Mortgagees shall not have responsibility for the control, care,
management or repair of the Mortgaged Property nor shall such Mortgagee be
responsible or liable for any negligence in the management, operation, upkeep,
repair or control of the Mortgaged Property resulting in loss or injury or death
to any licensee, employee, tenant or stranger or other Person.  Mortgagor shall
indemnify and hold harmless the Mortgagees from and against any and all loss,
cost and liability incurred by Mortgagee in connection with any of the foregoing
which are not the responsibility of the Mortgagees in accordance with this
Section; provided, however, that Mortgagor shall not be liable for such
         --------                                                      
indemnification to any Mortgagee to the extent that any such suit, action,
proceeding, claim, damage, loss, liability or expense results from such
Mortgagee's gross negligence or willful misconduct.


                       ARTICLE VII  Concerning Mortgagee

          SECTION 7.1.  [Intentionally Omitted]



                                 ARTICLE VIII
                                 Miscellaneous

          SECTION 8.1.  Termination; Defeasance.  This Mortgage and the security
                        -----------------------                                 
interests created hereby shall terminate when the Secured Obligations due and to
become due 

                                      -27-

 
shall have been paid or performed in full. Upon termination, Mortgagee shall
execute and deliver to Mortgagor an appropriate release and such other documents
reasonably required by Mortgagor, and shall turn over to Mortgagor any of the
Mortgaged Property and any other files, documents or material held by Mortgagee.
Mortgagor shall pay Mortgagee's reasonable expenses (including attorneys' fees
and expenses) in connection with the termination hereof and any transfer of such
property.

          SECTION 8.2.  Rights Cumulative; Waivers.  To the fullest extent
                        --------------------------                        
permitted by law, the rights and remedies of the Mortgagees under this Mortgage
and the other Loan Documents shall be cumulative.  The exercise, failure to
exercise or delay in exercising any right or remedy by any of the Mortgagees
shall not prevent any of them from exercising any other right or remedy or
exercising such right or remedy at a later time.

          SECTION 8.3.  Fees and Expenses.  Subject to Section 10.2 of the
                        ----------------- 
Credit Agreement (to the extent applicable), Mortgagor shall pay upon demand all
fees and expenses (including reasonable attorneys' fees and expenses) incurred
by Mortgagee in connection with (a) the administration of this Mortgage and any
amendment or modification hereof, (b) the custody or preservation of, or the
sale of, collection from, or other realization upon, any of the Mortgaged
Property or (c) the failure by Mortgagor to perform or observe any of the
provisions hereof and the exercise or enforcement of any of the rights of, and
collection of amounts due to, the Mortgagees hereunder.

          SECTION 8.4.  Indemnification.
                        --------------- 

          (a)  Indemnity.  Mortgagor shall protect, indemnify and hold harmless
               ---------                                                       
each Mortgagee and each of its Indemnified Parties from and against all
liabilities, obligations, claims, damages, penalties, causes of action, costs,
fees, charges and expenses (including reasonable attorneys' fees and expenses
and further including in connection with the enforcement of this indemnity)
(each, a "Loss") imposed upon or incurred by or asserted against any such
          ----                                                           
Mortgagee or Indemnified Party by reason of (i) any accident, injury or death of
persons or loss of or damage to property occurring on or about the Property or
any part thereof; (ii) any use or nonuse of the Property or any part thereof;
(iii) any failure on the part of Mortgagor to perform or comply with any of the
terms of this Mortgage (including with respect to environmental matters under
Article IX of this Mortgage); (iv) the performance of any labor or services or
the furnishing of any materials or other property in respect of the Mortgaged
Property or any part thereof; (v) any negligent or tortious act or omission on
the part of Mortgagor or any of its agents, employees, contractors, licensees,
lessees or invitees; (vi) any contest of any Legal Requirement, Imposition or
other matter or (vii) any other matter or thing arising from or attributable to
Mortgagor's interest in the Mortgaged Property and/or receipt of any income
therefrom, other than Losses resulting from Mortgagee's gross negligence or
willful misconduct, as determined by a court of competent jurisdiction.  If any
action, suit or proceeding is brought against Mortgagee or any Indemnified Party
by reason of 

                                      -28-

 
any such occurrence, Mortgagor, upon such Person's request, will at Mortgagor's
expense resist and defend such action, suit or proceeding or will cause the same
to be resisted and defended by counsel for the insurer of the liability or by
counsel approved by such Person. Any amounts payable to any Mortgagee or any
Indemnified Party pursuant to the indemnity contained in this Section shall be
due within ten (10) days after demand therefor, and if not paid when due shall
bear interest at the Overdue Rate from and including the date due to the date of
payment by Mortgagor; and all such amounts, together with all such interest,
shall be deemed part of the Secured Obligations secured by this Mortgage. The
indemnity set forth in this Section shall survive the repayment in full of the
Secured Obligations and the release of any and all liens of Mortgagee, the
transfer of any and all right, title and interest in and to the Mortgaged
Property, or any part thereof, to any Person and the satisfaction of the Secured
Obligations.

          (b)  Third-Party Beneficiaries.  Each Indemnified Party shall be a
               -------------------------                                    
third-party beneficiary hereof and shall be entitled to, and to enforce, all of
the rights, benefits and protections afforded herein to an Indemnified Party, as
if such Indemnified Party were a party hereto.

          SECTION 8.5.  Notices.  All notices and other communications provided
                        -------                                                
to any party in connection with this Mortgage shall be given and effective as
follows:

          (a)  If to the Lenders or to Mortgagee, at:

               Wexford Management LLC
               411 West Putnam Avenue
               Greenwich, Connecticut 06830
               Telephone:  (203) 862-7000
               Attention:  Arthur H. Amron
               Facsimile:  (203) 862-7312
               and
               Attention:  Jay L. Maymudes
               Facsimile:  (203) 862-7350

               With a copy to:

               Howard, Smith & Levin
               1330 Avenue of the Americas
               New York, New York  10019
               Attention:  Michael B. Hopkins, Esq.
               Telephone:  (212) 841-1000
               Facsimile:  (212) 841-1010

                                      -29-

 
          (b)  If to Mortgagor, at:

               c/o Thermatrix Inc.
               308 N. Peters Road, Suite 100
               Knoxville, Tennessee  37922
               Attention:  Edward E. Greene
               Telephone:  (423) 539-9603
               Facsimile:  (423) 670-4091

               With a copy to

               Wilson Sonsini Goodrich & Rosati,
               650 Page Mill Road
               Palo Alto, CA 94304
               Attention: Michael J. Danaher, Esq.
               Telephone: (650) 493-9300
               Facsimile: (650) 493-6811

or at such other address as may be substituted by notice given as herein
provided. The giving of any notice required hereunder may be waived in writing
by the party entitled to receive such notice. Every notice, demand, request,
consent, approval, declaration or other communication hereunder shall be deemed
to have been duly given or served on the date on which personally delivered,
with receipt acknowledged, telecopied and confirmed by telecopy answerback or
three (3) Business Days after the same shall have been deposited in the United
States mail. Failure or delay in delivering copies of any notice, demand,
request, consent, approval, declaration or other communication to the persons
designated above to receive copies shall in no way adversely affect the
effectiveness of such notice, demand, request, consent, approval, declaration or
other communication.

          SECTION 8.6.   Amendment and Waiver.  Except as otherwise provided
                         --------------------                               
herein, this Mortgage may be amended, and observance of any term of this
Mortgage may be waived, with (and only with) the written consent of Mortgagor
and Mortgagee.


          SECTION 8.7.   Expenses of Mortgagor's Agreements and Duties.  The
                         ---------------------------------------------      
terms, conditions, covenants and agreements to be observed or performed by
Mortgagor under this Mortgage shall be observed or performed by it at its sole
cost and expense.

          SECTION 8.8.   Mortgagee's Right to Use Agents and to Act in Name of
                         -----------------------------------------------------
Mortgagor.  Mortgagee may exercise its rights and remedies under this Mortgage
- ---------                                                                     
through the Agent or any other agent or designee and, in the exercise thereof,
Mortgagee or any such other Person may act in its own name or in the name and on
behalf of Mortgagor.

          SECTION 8.9.   No Compensation or Expense.  Mortgagee may exercise its
                         --------------------------                             

                                      -30-

 
rights and remedies under this Mortgage (a) without payment of any rent, license
fee or compensation of any kind to Mortgagor and (b) for the account, and at the
expense, of Mortgagor.

          SECTION 8.10.  Limitation of Obligations with Respect to Mortgaged
                         ---------------------------------------------------
Property.
- -------- 

          (a)  Reasonable Care. Mortgagee shall have any duty or liability to
               ---------------                                               
protect or preserve any Mortgaged Property or to preserve rights pertaining
thereto other than the duty to use reasonable care in the custody and
preservation of any Mortgaged Property in its actual possession.  Mortgagee
shall be deemed to have exercised reasonable care in the custody and
preservation of any Mortgaged Property in its possession if such Mortgaged
Property is accorded treatment substantially equal to that which Mortgagee
accords its own like property.  Mortgagee shall be relieved of all
responsibility for any Mortgaged Property in its possession upon surrendering
it, or tendering surrender of it, to Mortgagor.

          (b)  No Obligations.  Nothing contained in this Mortgage shall be
               --------------                                              
construed as requiring or obligating Mortgagee, and no Mortgagee shall be
required, or obligated, to (i) make any demand, or to make any inquiry as to the
nature or sufficiency of any payment received by it, or to present or file any
claim or notice or take any action, with respect to any Mortgaged Property or
the monies due or to become due thereunder or in connection therewith, (ii)
ascertain or take action with respect to calls, conversions, exchanges,
maturities, tenders, offers or other matters relating to any Mortgaged Property,
whether or not any Mortgagee has or is deemed to have knowledge or notice
thereof, (iii) take any necessary steps to preserve rights against any prior
parties with respect to any Mortgaged Property or (iv) notify Mortgagor or any
other Person of any decline in the value of any Mortgaged Property.

          SECTION 8.11.  Time of the Essence.  Time is of the essence with
                         -------------------                              
respect to the various obligations of Mortgagor and rights and remedies of
Mortgagee under this Mortgage.

          SECTION 8.12.  Inconsistency with Loan Documents.  Mortgagor and
                         ---------------------------------                
Mortgagee are parties to the Security Agreement.  If any term or provision
hereof with respect to any Mortgaged Property hereunder which is Personal
Property and which is the subject of and covered by the Security Agreement is
inconsistent with any term or provision of the Security Agreement, then such
term or provision of the Security Agreement shall govern and control with
respect to such Personal Property to the extent of such inconsistency.

          SECTION 8.13.  Severability.  If any provision of this Mortgage shall
                         ------------                                          
be invalid, illegal or unenforceable in any jurisdiction, the remaining
provisions shall continue to be valid and enforceable and such provision shall
continue to be valid and enforceable in any other jurisdiction.

                                      -31-

 
          SECTION 8.14.  Headings.  The headings of the Sections and subsections
                         --------                                               
are for convenience and shall not affect the meaning of this Mortgage.

          SECTION 8.15.  Assignment; Benefit.  Mortgagor may not sell, convey,
                         ------------------                                   
assign, transfer or otherwise dispose of all or any portion of its rights and
obligations under this Mortgage.  Each Mortgagee may assign all or any part of
its rights under this Mortgage as provided in the Credit Agreement.  Mortgagor
and Mortgagee, and their permitted successors and assigns shall be bound by this
Mortgage.  They (and their Indemnified Parties) shall be the only persons
entitled to its benefits.

          SECTION 8.16.  GOVERNING LAW.  THIS MORTGAGE SHALL BE GOVERNED BY, AND
                         -------------                                          
CONSTRUED AND ENFORCED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.
NOTWITHSTANDING THE FOREGOING, (A) MATTERS RESPECTING TITLE TO THE MORTGAGED
PROPERTY AND THE CREATION, PERFECTION, PRIORITY AND FORECLOSURE OF LIENS ON, AND
SECURITY INTERESTS IN, THE MORTGAGED PROPERTY SHALL BE GOVERNED BY, AND
CONSTRUED AND ENFORCED IN ACCORDANCE WITH, THE INTERNAL LAW OF THE STATE WITHOUT
GIVING EFFECT TO THE CONFLICTS-OF-LAW RULES AND PRINCIPLES OF THE STATE; (B)
MORTGAGOR AGREES THAT WHETHER OR NOT DEFICIENCY JUDGMENTS ARE AVAILABLE UNDER
THE LAWS OF THE STATE AFTER A FORECLOSURE OR SALE (JUDICIAL OR NONJUDICIAL) OF
THE MORTGAGED PROPERTY, OR ANY PORTION THEREOF, OR ANY OTHER REALIZATION THEREON
BY MORTGAGEE, MORTGAGEE SHALL HAVE THE RIGHT, TO THE FULLEST EXTENT PERMITTED BY
APPLICABLE LAW, TO SEEK SUCH A DEFICIENCY JUDGMENT AGAINST MORTGAGOR IN OTHER
STATES OR FOREIGN JURISDICTIONS; AND (C) MORTGAGOR AGREES THAT, TO THE EXTENT
MORTGAGEE OBTAINS A DEFICIENCY JUDGMENT IN ANY OTHER STATE OR FOREIGN
JURISDICTION THEN, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, SUCH PARTY
SHALL HAVE THE RIGHT TO ENFORCE SUCH JUDGMENT IN THE STATE, AS WELL AS IN OTHER
STATES OR FOREIGN JURISDICTIONS.

          SECTION 8.17.  WAIVER OF JURY TRIAL.  MORTGAGOR HEREBY KNOWINGLY,
                         --------------------                              
VOLUNTARILY AND INTENTIONALLY WAIVES ANY RIGHTS IT MAY HAVE TO A TRIAL BY JURY
IN RESPECT OF ANY LITIGATION BASED HEREON, OR ARISING OUT OF, UNDER OR IN
CONNECTION WITH, THIS MORTGAGE OR ANY OTHER LOAN DOCUMENT, OR ANY COURSE OF
CONDUCT, COURSE OF DEALING, STATEMENTS (WHETHER ORAL OR WRITTEN) OR ACTIONS OF
MORTGAGEE OR MORTGAGOR IN CONNECTION HEREWITH.  MORTGAGOR ACKNOWLEDGES AND
AGREES THAT IT HAS 

                                      -32-

 
RECEIVED FULL AND SUFFICIENT CONSIDERATION FOR THIS PROVISION (AND EACH OTHER
PROVISION OF EACH NOTE DOCUMENT TO WHICH IT IS A PARTY) AND THAT THIS PROVISION
IS A MATERIAL INDUCEMENT FOR MORTGAGEE ENTERING INTO THIS MORTGAGE.

          SECTION 8.18.  CONSENT TO JURISDICTION.  EACH OF THE MORTGAGOR AND
                         -----------------------                            
MORTGAGEE IRREVOCABLY SUBMITS TO THE NON-EXCLUSIVE JURISDICTION OF (I) THE
SUPREME COURT OF THE STATE OF NEW YORK, NEW YORK COUNTY AND (II) THE UNITED
STATES DISTRICT COURT FOR THE SOUTHERN DISTRICT OF NEW YORK, FOR THE PURPOSES OF
ANY SUIT, ACTION OR OTHER PROCEEDING ARISING OUT OF THIS MORTGAGE OR ANY
TRANSACTION CONTEMPLATED HEREBY.  EACH OF THE MORTGAGOR AND MORTGAGEE FURTHER
AGREES THAT SERVICE OF ANY PROCESS, SUMMONS, NOTICE OR DOCUMENTS BY UNITED
STATES REGISTERED MAIL TO SUCH PARTY'S RESPECTIVE ADDRESS FOR NOTICES SET FORTH
IN SECTION 8.5 SHALL BE EFFECTIVE SERVICE OF PROCESS FOR ANY ACTION, SUIT OR
PROCEEDING IN NEW YORK WITH RESPECT TO ANY MATTERS TO WHICH IT HAS SUBMITTED TO
JURISDICTION IN THIS SECTION.  EACH OF THE MORTGAGOR AND MORTGAGEE IRREVOCABLY
AND UNCONDITIONALLY WAIVES ANY OBJECTION TO THE LAYING OF VENUE OF ANY ACTION,
SUIT OR PROCEEDING ARISING OUT OF THIS MORTGAGE OR THE TRANSACTIONS CONTEMPLATED
HEREBY IN (A) THE SUPREME COURT OF THE STATE OF NEW YORK, NEW YORK COUNTY AND
(B) THE UNITED STATES DISTRICT COURT FOR THE SOUTHERN DISTRICT OF NEW YORK, AND
HEREBY FURTHER IRREVOCABLY AND UNCONDITIONALLY WAIVES AND AGREES NOT TO PLEAD OR
CLAIM IN ANY SUCH COURT THAT ANY SUCH ACTION, SUIT OR PROCEEDING BROUGHT IN ANY
SUCH COURT (OR IN ANY COURT DESCRIBED BELOW) HAS BEEN BROUGHT IN AN INCONVENIENT
FORUM.  MORTGAGOR ACKNOWLEDGES THAT IN ANY ACTION OR PROCEEDING TO ENFORCE
PAYMENT OF THE SECURED OBLIGATIONS OR ANY OTHER RIGHT OF THE MORTGAGEE OR THE
LENDERS UNDER THIS MORTGAGE, IT WAIVES THE RIGHT TO ASSERT ANY COUNTERCLAIM OF
ANY KIND OTHER THAN A COMPULSORY COUNTERCLAIM.  NOTWITHSTANDING THE FOREGOING,
NOTHING HEREIN SHALL AFFECT THE RIGHT OF MORTGAGEE TO SERVE PROCESS IN ANY
MANNER PERMITTED BY STATE LAW OR TO COMMENCE PROCEEDINGS OR OTHERWISE PROCEED
AGAINST MORTGAGOR OR OTHERWISE TO FORECLOSE THIS MORTGAGE OR EXERCISE ANY OTHER
REMEDIES HEREUNDER IN ANY APPROPRIATE STATE COURT OR FEDERAL COURT IN THE STATE.

          SECTION 8.19.  Limitation on Interest Payable.  It is the intention of
                         ------------------------------                         
the parties to conform strictly to the usury laws, whether State or federal,
that are applicable to the 

                                      -33-

 
transaction of which this Mortgage is a part. All agreements between Mortgagor
and Mortgagee whether now existing or hereafter arising and whether oral or
written, are hereby expressly limited so that in no contingency or event
whatsoever shall the amount paid or agreed to be paid by Mortgagor for the use,
forbearance or detention of the money to be loaned under the Credit Agreement or
any Loan Document, or for the payment or performance of any covenant or
obligation contained herein or in the Credit Agreement or any related document
or other Loan Document, exceed the maximum amount permissible under applicable
federal or state usury laws. If under any circumstances whatsoever fulfillment
of any such provision, at the time performance of such provision shall be due,
shall involve exceeding the limit of validity prescribed by law, then the
obligation to be fulfilled shall be reduced to the limit of such validity. If
under any circumstances Mortgagor shall have paid an amount deemed interest by
applicable law, which would exceed the highest lawful rate, such amount that
would be excessive interest under applicable usury laws shall be applied to the
reduction of the principal amount owing in respect of the Secured Obligations
and not to the payment of interest, or if such excessive interest exceeds the
unpaid balance of principal and any other amounts due hereunder, the excess
shall be refunded to Mortgagor. All sums paid or agreed to be paid for the use,
forbearance or detention of the principal under any extension of credit by
Mortgagee shall, to the extent permitted by applicable law, and to the extent
necessary to preclude exceeding the limit of validity prescribed by law, be
amortized, prorated, allocated and spread from the date of this Mortgage until
payment in full of the Secured Obligations so that the actual rate of interest
on account of such principal amounts is uniform throughout the term hereof.

          SECTION 8.20.  Covenants To Run With the Land.  All of the grants,
                         ------------------------------                     
covenants, terms, provisions and conditions in this Mortgage shall run with the
Land and shall apply to, and bind the successors and assigns of Mortgagor.  If
there shall be more than one mortgagor, the covenants and warranties hereof
shall be joint and several.

          SECTION 8.21.  No Merger.  The rights and estate created by this
                         ---------                                        
Mortgage shall not, under any circumstances, be held to have merged into any
other estate or interest now owned or hereafter acquired by Mortgagee unless
Mortgagee shall have consented to such merger in writing.

          SECTION 8.22.  Relationship.  The relationship of Mortgagee to
                         ------------                                   
Mortgagor hereunder is strictly and solely that of mortgagor and mortgagee and
nothing contained in this Mortgage, or any other document or instrument now
existing and delivered in connection therewith or otherwise in connection with
the Secured Obligations is intended to create, or shall in any event or under
any circumstance be construed as creating a partnership, joint venture, tenancy-
in-common, joint tenancy or other relationship of any nature whatsoever between
Mortgagee and Mortgagor other than as mortgagee and mortgagor.

                                      -34-

 
                                   ARTICLE IX
                             Environmental Matters

          SECTION 9.1.  Notice of Environmental Matters.
                        ------------------------------- 

          (a)  Delivery of Notice.  Mortgagor shall notify Mortgagee promptly
               ------------------                                            
after, and in any event within three (3) Business Days after, any Responsible
Officer of Mortgagor obtains knowledge of one or more of the matters described
in Section 6.2(i) of the Credit Agreement with respect to the Property or
Mortgagor, as if the same was a direct obligation of Mortgagor set forth at
length herein.

          (b) Contents of Notice.  All such notices shall comply with the
              ------------------                                         
requirements of such Section.  In addition, Mortgagor shall provide Mortgagee
with copies of all communications between Mortgagor and any Person required by
or otherwise relating to any of the matters described in such Section.

          SECTION 9.2.  Obligations of Mortgagor.  Mortgagor hereby covenants to
                        ------------------------                                
comply with, and to cause its officers, directors, shareholders, partners,
agents, servants and employees and each tenant of the Property to comply with,
all of the obligations applicable to Mortgagor, the Property and each such
tenant with respect to the Property set forth in Section 6.6(b) of the Credit
Agreement, as if each of the same was a direct obligation of Mortgagor set forth
at length herein.


                                   ARTICLE X
                         Local Jurisdiction Provisions

          Notwithstanding anything to the contrary set forth elsewhere in this
Mortgage:

          SECTION 10.1.  Mortgage Covenants.  The Mortgaged Property is granted,
                         ------------------                                     
mortgaged and conveyed WITH MORTGAGE COVENANTS.

          SECTION 10.2.  Statutory Conditions.  This Mortgage is given upon the
                         --------------------                                  
STATUTORY CONDITION, which is incorporated herein by reference, for breach of
which Mortgagee shall have the right to foreclose this Mortgage under any legal
method of foreclosure in existence at the time or now existing, or under any
other applicable law, including, without limitation, the STATUTORY POWER OF
SALE, which is expressly incorporated herein by reference, to the extent
authorized or allowed by any present or future law of the State of Maine.  In
connection therewith, Mortgagor acknowledges that this Mortgage secures a loan
or loans for business and commercial purposes and that this Mortgage is given
primarily for a business, commercial or agricultural purpose.  In the event of a
conflict between the STATUTORY CONDITION and the terms and provisions of this

                                      -35-

 
Mortgage, the terms and provisions of this Mortgage shall control, to the extent
permitted by Maine law.

          SECTION 10.3.  No Waiver.  Mortgagor agrees for itself, its successor
                         ---------                                             
and assigns, that the acceptance, before the expiration of the right of
redemption and after the commencement of foreclosure proceedings of this
Mortgage, of insurance proceeds, eminent domain awards, rents or anything else
of value to be applied on or to the Secured Obligations by Mortgagee or any
person or party holding under Mortgagee shall not constitute a waiver of such
foreclosure, and this agreement by Mortgagor shall be that agreement referred to
in 14 M.R.S.A. (S) 6204, as amended, as necessary to prevent such waiver of
foreclosure.  This agreement by Mortgagor is intended to apply to the acceptance
and such applications of any such insurance proceeds, eminent domain awards,
rents and other sums or anything else of value, whether the same shall be
accepted from, or for the account of, Mortgagor or from any other sources
whatsoever by Mortgagee or by any person or party holding under Mortgagee at any
time or times in the future while any portion of the Secured Obligations shall
remain outstanding.

          SECTION 10.4.  Written Agreement.  Mortgagor is hereby notified and
                         -----------------                                   
hereby confirms and acknowledges that, pursuant to 10 M.R.S.A. (S) 1146(2), to
the extent applicable, in order to maintain an action against Mortgagee with
respect to a promise, contract or agreement to lend money, extend credit,
forbear from collection of a debt or make any other accommodation for the
repayment of a debt for more than $250,000, such promise, contract or agreement
(or some memorandum or note thereof) must be both (a) in writing and (b) signed
by Mortgagee.

          SECTION 10.5.  Open-End Mortgage.  This Mortgage is an open-end
                         -----------------                               
mortgage that secures existing indebtedness, "Future Advances" "Protective
Advances" and "Contingent Obligations" as such terms are defined in 33 M.R.S.A.
(S) 505.  The maximum aggregate amount of Contingent Obligations secured by this
Mortgage shall not at any time exceed the total amount of $10,000,000.  The
maximum aggregate amount of all debts or obligations secured by this Mortgage,
including Future Advances, but excluding Contingent Obligations and Protective
Advances, shall not at any time exceed the total amount of $10,000,000.  The
future advances secured hereby shall be made to or for the account of Mortgagor
and may be made pursuant to promissory notes, line of credit agreements or other
instruments evidencing such future advances that may be hereafter executed and
delivered by Mortgagor to Mortgagee.  In the event that any notice described in
subsections 5(a) and 5(b) of 33 M.R.S.A. (S) 505 is recorded or is received by
Mortgagee, any commitment, agreement or obligation to make future advances to or
for the benefit of Mortgagor shall immediately cease.

          SECTION 10.6.  Information Under Uniform Commercial Code.  This
                         -----------------------------------------       
instrument constitutes a financing statement under Article 9 the Maine Uniform
Commercial Code covering the Personal Property and fixtures included within the
Mortgaged Property and 

                                      -36-

 
described in this Mortgage. The debtor is Mortgagor and the secured parties are
Mortgagees. The mailing address of the secured party (Mortgagee) from which
information concerning the security interest may be obtained is as follows:

                           Wexford Management LLC
                           411 West Putnam Avenue
                           Greenwich, Connecticut 06830
                           Telephone:   (203) 862-7000
                           Attention:  Arthur H. Amron
                           Facsimile:   (203) 862-7312
                           and
                           Attention:  Jay L. Maymudes
                           Facsimile:   (203) 862-7350

and the mailing address of the debtor (Mortgagor), is as follows:

                           c/o Thermatrix Inc.
                           308 N. Peters Road, Suite 100
                           Knoxville, Tennessee  37922
                           Attention:  Edward E. Greene
                           Telephone:  (423) 539-9603
                           Facsimile:  (423) 670-4091


          SECTION 10.7.  Notice Pursuant to 18-A M.R.S.A. (S) 5-508. Pursuant to
                         ------------------------------------------
various provisions and Sections of this Mortgage, Mortgagor has appointed
Mortgagee as its Attorney-in-fact. To the extent that such appointments by
Mortgagor constitute the granting of a Durable Power of Attorney within the
meaning of 18-A M.R.S.A. (S) 5-508, the following (to the extent applicable)
shall apply:

          Notice to the Principal (Mortgagor): As the "Principal", you are using
this Durable Power of Attorney to grant power to another person (called the
"Agent" or "Attorney-in-fact") to make decisions about your money, property or
both and to use your money, property or both on your behalf. If this written
Durable Power of Attorney does not limit the powers that you give your Agent,
your Agent will have broad and sweeping powers to sell or otherwise dispose of
your property and spend your money without advance notice to you or approved by
you. Under this document, your Agent will continue to have these powers after
you become incapacitated, and you may also choose to authorize your Agent to use
these powers before you become incapacitated. The powers that you give your
Agent are explained more fully in the Maine Revised Statutes, Title 18-A,
Sections 5-501 to 5-508, and in Maine case law. You have the right to revoke or
take back this Durable Power of Attorney at any time as long as you are of sound
mind. If there is anything about this Durable Power of

                                      -37-

 
Attorney that you do not understand, you should ask a lawyer to explain it to
you.

          Notice to the Agent (Mortgagee): As the "Agent" or "Attorney-in-fact",
you are given power under this Durable Power of Attorney to make decisions about
the money, property or both belonging to the Principal and to spend the
Principal's money, property or both on that person's behalf in accordance with
the terms of this Durable Power of Attorney. This Durable Power of Attorney is
only valid if the Principal is of sound mind when the Principal signs it. As the
Agent, you are under a duty (called a "fiduciary duty") to observe the standards
observed by a prudent person dealing with the property of another. The duty is
explained more fully in the Maine Revised Statutes, Title 18-A, sections 5-501
to 5-508 and 7-302 and in Maine case law. As the Agent, you are not entitled to
use the money or property for your own benefit or to make gifts to yourself or
others unless the Durable Power of Attorney specifically gives you the authority
to do so. As the Agent, your authority under this Durable Power of Attorney will
end when the Principal dies and you will not have the authority to administer
the estate unless you are authorized to do so in accordance with the Maine
Probate Code. If you violate your fiduciary duty under this Durable Power of
Attorney, you may be liable for damages and may be subject to criminal
prosecution. If there is anything about this Durable Power of Attorney or your
duties under it that you do not understand, you should ask a lawyer to explain
it to you.

          Notwithstanding the foregoing, nothing in this Section 10.7 shall
expand any of the rights or powers granted by Mortgagor to Mortgagee pursuant to
any "power of attorney" set forth elsewhere in this Mortgage.

          SECTION 10.8 Authority of Wexford Management, LLC. By acceptance
                       ------------------------------------
hereof, each of the Mortgagees acknowledges and confirms to Mortgagor that,
pursuant to the Credit Agreement, it has designated Wexford Management LLC as
its Agent for the purpose of giving all consents and approvals under this
Mortgage on such Mortgagee's behalf.

                                      -38-

 
          IN WITNESS WHEREOF, Mortgagor has duly executed and delivered this
Mortgage as of the date first written above.


                                             WAHLCO ENGINEERED PRODUCTS,
                                             INC.


                                                  
                                             By:  /s/ Daniel S. Tedone
                                                ---------------------------
                                                Name:  Daniel S. Tedone

                                                Title: Executive Vice President 
                                                       & Chief Financial Officer

Attest:


________________________
Name:
Title:

                                      -39-

 
STATE OF NEW YORK  )                      
                   )  ss.:                 
COUNTY OF NEW YORK )                       


          On February 25, 1999, personally appeared the above-named
Daniel S. Tedone as Executive Vice President and Chief Financial Officer of
Wahlco Engineered Products, Inc., and acknowledged the foregoing instrument to
be his/her free act and deed in his/her said capacity and the free act and deed
of said Corporation.


                                  Before me,


                                  /s/ Catherine Jones
                                  -------------------------------
                                  Notary Public
                                  Type or Print Name:
                                
                                  Catherine Jones
                                  -------------------------------
                                  Notary Public, State of New York
                                  No. 01J05088551
                                  Qualified in New York County
                                  Commission Expires 11/17/1999.

                                      -40-

 
                                                                         Annex-1


Wexford Capital Partners II, L.P., a Delaware limited partnership,

Wexford Overseas Partners I, L.P., a Delaware limited partnership,

Wexford Special Situations 1996, L.P., a Delaware limited partnership,

Wexford Special Situations 1996 Institutional, L.P., a Delaware limited
partnership,

Wexford Special Situations 1996 Limited, a Cayman Islands exempted company,

Wexford-Euris Special Situations 1996, L.P., a Delaware limited partnership,

and their respective successors and assigns.

                                    Annex-1

 
                                                                       EXHIBIT A

                                                                     to Mortgage


                              DESCRIPTION OF LAND



29 Lexington Street

Lewiston, ME 04240


described more particularly as follows:


Those two (2) certain parcels conveyed to Mortgagor by deed from Bachmann
Holdings Company, f/k/a Bachmann Industries, Inc., dated July 1, 1985, and
recorded in the Androscoggin County Registry of Deeds, Book 2019, Page 237, and
described as follows:

A certain lot or parcel of land, with any buildings thereon, situated in the
City of Lewiston, Androscoggin County, State of Maine, bounded and described as
follows:

BEGINNING at a point on the southwesterly line of Lexington Street, said point
being five hundred ten and seventeen hundredths (510.17) feet northwesterly from
a monument at the westerly corner of the intersection of Lexington Street and
Westminster Street; thence North 36E44' 35" West along the southwesterly line of
said Lexington Street a distance of three hundred fifty (350) feet; thence South
58E 28' 05" West a distance of three hundred fifty and sixty-six hundredths
(350.66) feet; thence South 38 50' 06" East a distance of three hundred
eighty-two and ten hundredths (382.10) feet; thence North 53 15' 25" East a
distance of three hundred thirty-five and twenty-six hundredths (335.26) foot to
the point of beginning.

Meaning and intending to describe Lot Number thirteen (13) shown on plan
entitled "Revision #1 Lewiston Industrial Park" (Sheet P-1) recorded at the
Androscoggin County Registry of Deeds Office, in Plan Book 28, Pages 47-48.

Also another certain lot or parcel of land situated in the City of Lewiston,
Androscoggin County, State of Maine, bounded and described as follows:

                                      A-1

 
BEGINNING at a set iron rod located at the southeasterly corner of land conveyed
to Lewiston Industrial Park, Inc. by Francis J. Sabalauckas by deed dated July
19, 1983 and recorded in the Androscoggin County Registry of Deeds Book 1658,
Page 245; said iron rod being located North 51E 56' 49" East one hundred eighty
and no hundredths (180.00) feet from an iron pipe marking the apparent northerly
corner of land presently owned by Roland A. Caron (see deed recorded in Book
1277, Page 139, Androscoggin County Registry of Deeds); thence northeasterly one
thousand one hundred sixty one feet, more or less, (1,161) by land now or
formerly of the Lewiston Industrial Park, Inc., to the southwesterly line of Lot
#13 as shown on "Revision #1 Lewiston Industrial Park," Sheet P-1, recorded in
Plan Book 28, Page 47, said Lot #13 being presently occupied by Brachmann
Industries (see deed to Tuboflex, Inc., Book 1358, Page 176); thence North
38E50' 06" West three hundred sixty feet, more or less, (360'1) on the
southwesterly line of said Lot #13 to a point on the northwesterly line
described in said Sabalauckas deed (Book 1341, Page 258) said point being on the
southeasterly line of Dominique E. Bilodeau et al (see Book 981, Page 377 and
Book 1485, Page 164); thence south 53E34' 27" West twelve hundred forty-three
and seventy-three hundredths (1243.73) feet by the southeasterly line of said
Bilodeau to a set iron pipe; thence South 50E 26' East four hundred four and
eighty-two hundredths (404.82) feet by remaining land of Francis J. Sabalauckas
to the set iron rod at the point of beginning.

Tax Parcel No.:  00010885

                                      A-2

 
                                                                       EXHIBIT B

                                                                     to Mortgage


                              MATERIAL AGREEMENTS



                                     None.

                                      B-1

 
                                                                       EXHIBIT C

                                                                     to Mortgage


                            PERMITTED ENCUMBRANCES




          1.   Liens created or permitted by the Credit Agreement.

          2.   Zoning laws and regulations.

          3.   Any charges, liens or encumbrances existing as of the Effective
               Date.

                                      C-1

 
                                                                       Exhibit D

                                                                     to Mortgage



                     INFORMATION FOR FINANCING STATEMENTS



Chief Executive Office:                           29 Lexington Street
                                                  Lewiston, ME  04240



Principal Place of Business:                      29 Lexington Street
                                                  Lewiston, ME  04240



Location of Each Required Filing Office:

     1.   Secretary of State of Maine

     2.   Androscoggin County, State of Maine

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