<PAGE>   14

                        FOURTH AMENDMENT TO THE
               PAUL MUELLER COMPANY EMPLOYEE BENEFIT PLAN 
               AMENDED AND RESTATED AS OF MARCH 22, 1995

    WHEREAS Article VI of the Paul Mueller Company Employee Benefit 
Plan (referred to hereafter as the "Plan") provides that the Plan may 
be amended by resolution of the Trustees in accordance with the pro-
visions of the Declaration of Trust, be it resolved that the Plan is 
amended as follows:

 1.  The last sentence of Paragraph E) of the Subsection entitled 
     MEDICAL COVERED CHARGES of Section C MEDICAL CARE COVERAGE of 
     Article III Benefits is deleted in its entirety.

 2.  The second paragraph of the Subsection entitled MAXIMUM AMOUNTS 
     of Section C MEDICAL CARE COVERAGE of Article III Benefits is 
     deleted and replaced by the following paragraph.

     The amount of benefits payable for treatment of alco-
     holism, chemical dependency and drug addiction is 
     further limited to a maximum of $50,000 lifetime.

     Coverage for inpatient treatment of nervous or mental 
     conditions is limited to thirty (30) days per calendar 
     year and seventy-five (75) days lifetime (all days, 
     including those prior to January 1, 1998, are counted 
     toward the lifetime maximum).

 3.  The following paragraph is added at the end of the Subsection 
     entitled MAXIMUM AMOUNTS of Section C MEDICAL CARE COVERAGE of 
     Article III Benefits.

     Refer to Paragraph V) of the section entitled COVERED 
     MEDICAL CHARGES in this Part C for the $1,500 cardiac 
     rehabilitation services maximum.

 4.  The following sentence is added at the end of the fourth para-
     graph of the Section entitled CONTINUATION COVERAGE of Article II 
     Eligibility Provisions.

     A child born to or placed for adoption with a Participant 
     who is a Qualified Beneficiary is also a Qualified Benefi-
     ciary.

 5.  The words "or within the first sixty (60) days of Continuation 
     Coverage" are inserted between the words "Event" and "and" in the 
     fourth line of the second sentence of the ninth paragraph of the 
     Section entitled CONTINUATION COVERAGE of Article II Eligibility 
     Provisions.

 6.  The words "for the disabled Qualified Beneficiary as well as for 
     every other Qualified Beneficiary who lost coverage due to the 
     same Qualifying Event" are inserted between the words "period" 
     and "will" in the sixth line of the second sentence of the ninth 
     paragraph of the Section entitled CONTINUATION COVERAGE of Arti-
     cle II Eligibility Provisions.

 7.  The following definitions are added to the Subsection entitled 

                                  1

<PAGE>   15

     MEDICAL CARE DEFINITIONS of Section C MEDICAL CARE COVERAGE of 
     Article III Benefits.

     20)  "Enrollment Date" means the first day of coverage 
          under the Plan or, if there is a waiting period for 
          coverage, the first day of the waiting period.

     21)  "Prior Creditable Coverage" means continuous cover-
          age under any one of the following:

          -    An insured or self-insured group health plan
          -    Health insurance coverage
          -    Medicare
          -    Medicaid and Title X
          -    Indian Health Service Program
          -    State high risk pools
          -    Public health plans
          -    Peace Corps benefits

          provided (a) the Covered Individual furnishes the 
          Plan with a Certificate of Creditable Coverage or 
          other evidence of Prior Creditable Coverage satis-
          factory to the Trustees and (b) coverage before a 
          break in coverage of sixty-three (63) days or more 
          does not count as continuous coverage.

 8.  The words "the Covered Individual received any medical care, ser-
     vices or supplies within the three (3) month period immediately 
     before becoming covered under the Plan" in Paragraph 11) of the 
     Subsection entitled MEDICAL LIMITATIONS AND EXCLUSIONS of Section 
     C MEDICAL CARE COVERAGE of Article III Benefits are deleted and 
     replaced by the words "any medical advice, diagnosis, care or 
     treatment was received within the three (3) month period immedi-
     ately prior to the Covered Individual's Enrollment Date".

 9.  The words "the earlier of (a) the end of a period of three (3) 
     consecutive months during which the Covered Individual has not 
     received for or in connection with such Injury or Illness any 
     medical, surgical, hospital or nursing service or treatment of 
     any kind or any drugs or medicines lawfully obtainable only upon 
     prescription of a Physician, or (b) the end of the period of 
     twelve (12) consecutive months during which the Covered Indivi-
     dual has been continuously covered under the Plan, or (c) in the 
     case of a Participant, a period of six (6) consecutive months 
     during which the Participant has been so covered and continuously 
     at Active Work on a Full-Time Basis" in Paragraph 11) of the Sub-
     section entitled MEDICAL LIMITATIONS AND EXCLUSIONS of Section C 
     MEDICAL CARE COVERAGE of Article III Benefits are deleted and 
     replaced by the words "the earliest of (a) the end of a period 
     of three (3) consecutive months ending after the Covered Indivi-
     dual's Enrollment Date during which the Covered Individual has 
     not received for or in connection with such Injury or Illness any 
     medical, surgical, hospital or nursing service or treatment of 

                                  2

<PAGE>   16

     any kind or any drugs or medicines lawfully obtainable only upon 
     prescription of a Physician or (b) in the case of a Participant, 
     a period of six (6) consecutive months during which the Partici-
     pant has been continuously covered under the Plan and continu-
     ously at Active Work on a Full-Time Basis or (c) the end of the 
     period of twelve (12) consecutive months following the Covered 
     Individual's Enrollment Date; provided, however, that this twelve 
     (12) consecutive month period shall be reduced by the Covered 
     Individual's aggregate periods of Prior Creditable Coverage;".

10.  The words "or (c) to a Child of a Participant who becomes a 
     Covered Individual upon adoption (or placement awaiting adoption) 
     by the Participant.  In addition, this Paragraph (11) shall not 
     restrict the coverage under this Plan of any child adopted by a 
     Participant solely on the basis of a preexisting condition of 
     such child at the time he would otherwise be eligible for cover-
     age, so long as the adoption occurs while the Participant is 
     eligible for coverage under this Plan.  See Paragraph 6 of the 
     section entitled DEFINITIONS in Article II for a definition of 
     the term "adopted.")" in Paragraph 11) of the Subsection entitled 
     MEDICAL LIMITATIONS AND EXCLUSIONS of Section C MEDICAL CARE COV-
     ERAGE of Article III Benefits are deleted and replaced by the 
     words "or (c) pregnancy, subject to other limits and conditions 
     on pregnancy benefits provided elsewhere in the Plan; further, a 
     newborn or adopted Child (see Paragraph 6 of the section entitled 
     DEFINITIONS in Article II for a definition of the term "adop-
     tion") of a Participant is deemed to have at least twelve (12) 
     months of Prior Creditable Coverage, which will normally permit 
     the Child to avoid the Plan's preexisting conditions restriction; 
     however, this special rule for Children only applies to a Child 
     who does not become covered under the Plan immediately upon birth 
     or adoption if the Child was enrolled under Prior Creditable Cov-
     erage within thirty (30) days after the birth or adoption and 
     ceases to apply after the Child experiences a sixty-three (63) 
     day or longer break in Prior Creditable Coverage."

11.  The words "first eighteen (18) months (or twenty-one (21) months 
     if the patient has had a kidney transplant)" in the Subsection 
     entitled EFFECT OF ELIGIBILITY FOR MEDICARE COVERAGE ON PLAN 
     BENEFITS of Section C MEDICAL CARE COVERAGE of Article III Bene-
     fits are deleted and replaced by the words "first thirty (30) 
     months".

12.  The words ", Nurse Practitioner (other than a Nurse Midwife)" are 
     inserted between the words "Chiropractor" and "Clinical" in Para-
     graph 2) of the Subsection entitled MEDICAL CARE DEFINITIONS of 
     Section C MEDICAL CARE COVERAGE of Article III Benefits.

13.  The words "or treated in a Residential Treatment Program or a 
     Nonresidential Treatment Program" are inserted between the words 
     "Hospital" and ", and" in Exception (a) of the Subsection en-
     titled MEDICAL EXPENSE BENEFIT of Section C MEDICAL CARE COVER-
     AGE of Article III Benefits.

14.  The portion of the first sentence of the Subsection entitled 
     MEDICAL EXPENSE BENEFIT of Section C MEDICAL CARE COVERAGE of 
     Article III Benefits added to the March 22, 1995, amended and 

                                  3

<PAGE>   17

     restated Plan Document by the Second Amendment is deleted and 
     replaced by the following.

     Subject to the applicable Medical Deductible requirement 
     and Maximum Amounts, benefits are payable in an amount 
     equal to:

     a.   In the case of (i) services rendered by a Preferred 
          Provider; (ii) radiology, pathology, anesthesiology 
          and ambulance services rendered by a service provider 
          who is not a Preferred Provider during an inpatient 
          or outpatient confinement at a Hospital which is a 
          Preferred Provider, which confinement is prescribed 
          by a Physician who is a Preferred Provider; and 
          (iii) prescription drugs, an amount equal to 90% 
          of the first $1,500 of Covered Expenses incurred 
          by a Covered Individual during a calendar year and 
          100% of Covered Expenses in excess of $1,500.

     b.   In the case of services other than those described 
          in (a) above, an amount equal to 80% of the first 
          $2,500 of Covered Expenses incurred by a Covered 
          Individual during a calendar year and 100% of 
          Covered Expenses in excess of $2,500.

     Charges payable at 90% under paragraph (a) above count 
     toward the $2,500 required to be paid at 80% under para-
     graph (b) above, and charges payable at 80% under para-
     graph (b) above count toward the $1,500 required to be 
     paid at 90% under paragraph (a) above.

15.  The portion of the Subsection entitled MEDICAL DEDUCTIBLE of Sec-
     tion C MEDICAL CARE COVERAGE of Article III Benefits added to the 
     March 22, 1995, amended and restated Plan Document by the Second 
     Amendment is deleted and replaced by the following.

     a.   In the case of (i) services rendered by a Preferred 
          Provider; (ii) radiology, pathology, anesthesiology 
          and ambulance services rendered by a service provider 
          who is not a Preferred Provider during an inpatient 
          or outpatient confinement at a Hospital which is a 
          Preferred Provider, which confinement is prescribed 
          by a Physician who is a Preferred Provider; and (iii) 
          prescription drugs, an amount equal to $100.

     b.   In the case of services other than those described 
          in (a) above, an amount equal to $200.

     Charges applied to the $100 deductible under paragraph 
     (a) above count toward the $200 deductible required under 
     paragraph (b) above, and charges applied to the $200 de-
     ductible under paragraph (b) above count toward the $100 
     deductible required under paragraph (a) above.

                                  4

<PAGE>   18

16.  The portion of the Subsection entitled MEDICAL DEDUCTIBLE, item 
     (2), of Section C MEDICAL CARE COVERAGE of Article III Benefits 
     added to the March 22, 1995, amended and restated Plan Document 
     by the Second Amendment is deleted and replaced by the following.

     a.   In the case of (i) services rendered by a Preferred 
          Provider; (ii) radiology, pathology, anesthesiology 
          and ambulance services rendered by a service provider 
          who is not a Preferred Provider during an inpatient 
          or outpatient confinement at a Hospital which is a 
          Preferred Provider, which confinement is prescribed 
          by a Physician who is a Preferred Provider; and (iii) 
          prescription drugs, an amount equal to $300.

     b.   In the case of services other than those described 
          in (a) above, an amount equal to $600,

     Charges applied to the $300 deductible under paragraph 
     (a) above count toward the $600 deductible required under 
     paragraph (b) above, and charges applied to the $600 de-
     ductible under paragraph (b) above count toward the $300 
     deductible required under paragraph (a) above.

17.  The Room and Board Maximum for Single Bed Accommodations set 
     forth in Paragraph A) of the Subsection entitled MEDICAL COVERED 
     CHARGES of Section C MEDICAL CARE COVERAGE of Article III Bene-
     fits is deleted and replaced by the following.

     Single Bed accommodation...Highest Semiprivate Charge for 
                                the area of the Hospital in 
                                which the patient is confined, 
                                except that no maximum applies 
                                if it is determined by the 
                                Trustees that, and only for 
                                the period of time that, it is 
                                medically necessary that the 
                                Covered Individual be isolated 
                                from other patients because of 
                                Illness that is highly conta-
                                gious or because the patient's 
                                immunodefense system has been 
                                so compromised that he or she 
                                must be protected from all bac-
                                teria.

18.  The following Paragraph V) is added to the Subsection entitled 
     MEDICAL COVERED CHARGES of Section C MEDICAL CARE COVERAGE of 
     Article III Benefits.

                                  5

<PAGE>   19

     V)   Charges for cardiac rehabilitation services, subject 
          to a maximum lifetime benefit of $1,500 per Covered 
          Individual.

19.  Paragraph 21) of the Subsection entitled MEDICAL LIMITATIONS AND 
     EXCLUSIONS of Section C MEDICAL CARE COVERAGE of Article III 
     Benefits is deleted and replaced by the following.

     21)  Exercise programs, except cardiac rehabilitation 
          services to the extent covered under Paragraph V) 
          of the section entitled MEDICAL COVERED CHARGES 
          in this Part C.

20.  Paragraph 10) of the Section entitled DEFINITIONS of Article II 
     Eligibility Provisions is deleted and replaced by the following.

     10)  "Retired Employee" means a person who (a) is sepa-
          rated from the active service of the Employer, (b) 
          is not engaged in active, full-time work, (c) has 
          attained age fifty-five (55) and (d) has a total 
          of five (5) years of employment with the Employer. 
          Retired Employees are eligible for employee Life 
          Insurance and employee and dependent Medical Care 
          Benefits only.

21.  The words "or following" are inserted between the words "of" and 
     "the" in the first line of the first sentence of the Section en-
     titled LIMITED SELF-PAYMENT PRIVILEGE FOR RETIRED EMPLOYEES AND 
     SURVIVING DEPENDENTS of Article II Eligibility Provisions.

22.  The portion of the Subsection entitled BENEFIT AMOUNT of Section 
     B WEEKLY DISABILITY INCOME COVERAGE of Article III Benefits added 
     to the March 22, 1995 amended and restated Plan Document by the 
     Second Amendment is deleted.

23.  The following Paragraph 8) is added to the Subsection entitled 
     WEEKLY DISABILITY INCOME LIMITATIONS AND EXCLUSIONS of Section B 
     WEEKLY DISABILITY INCOME COVERAGE of Article III Benefits.

     8)   of a Participant who is a participant in the Paul 
          Mueller Company Short-Term Disability Plan and the 
          Paul Mueller Company Long-Term Disability Plan.

24.  The Subsection entitled RECOVERY FROM THIRD PARTIES - SUBROGATION 
     of Section C MEDICAL CARE COVERAGE of Article III Benefits is de-
     leted and replaced by the following.

     RECOVERY FROM THIRD PARTIES - SUBROGATION

     1)   In the event of payment to or on behalf of any 
          covered person under this Plan, this Plan shall be 
          subrogated, to the extent of benefits paid under 
          this Plan, to any and all monies paid or payable 
          from any other person or plan to or on behalf of 

                                  6

<PAGE>   20

          the covered person, and shall be subrogated to any 
          and all claims of or on behalf of the covered person 
          against any other person or plan, by reason of the 
          illness or injury which occasioned the payment of 
          benefits under this Plan ("the Illness or Injury").  
          This Plan's rights as expressed in the preceding 
          sentence expressly encompass, but are not limited 
          to, monies paid or payable to or on behalf of the 
          covered person by persons or plans other than the 
          persons (or plans insuring such persons) who are 
          responsible for the Illness or Injury, as well 
          as claims of or on behalf of the covered person 
          against such persons (or plans insuring such per-
          sons) responsible for the Illness or Injury.

     2)   For purposes of these Subrogation and Reimbursement 
          provisions, the term "person or plan" shall include, 
          but is not limited to: (a) any person, insurance 
          company or other entity that is in any way respon-
          sible for the Illness or Injury, or is in any way 
          responsible for providing compensation, indemnifica-
          tion, or benefits for the Illness or Injury; (b) 
          any law or policy of insurance or accidental benefit 
          plan providing no-fault, uninsured, underinsured or 
          general group or individual liability coverage; (c) 
          any medical reimbursement insurance whether or not 
          purchased by the covered person submitting the claim, 
          or on whose behalf the claim is submitted; and (d) 
          any specific risk accident or health coverage or 
          insurance, including without limitation premises 
          or homeowners medical reimbursement coverage, and 
          student, student-athletic or student-team coverage 
          or insurance.  The term "covered person" means the 
          person to whom or on whose behalf this Plan paid 
          benefits for treatment of the Illness or Injury. 
          With respect to the Plan's right to subrogation 
          to the covered person's rights of recovery against 
          another person or plan, and whenever else it may be 
          appropriate, the term also means the covered person's 
          heirs, guardians, executors or other representatives.  

     3)   This Plan's rights to subrogation apply whether or 
          not the monies paid or payable from the other per-
          son or plan are sufficient to fully compensate the 
          covered person for his loss occasioned by the Ill-
          ness or Injury.  Further, the characterization of 
          any amounts paid or payable to or on behalf of a 
          covered person, whether under a settlement agree-
          ment, judgment, plan as defined herein, or other-
          wise, shall not affect the priority given this Plan 
          under these provisions with respect to such amounts.

     4)   Notwithstanding any other provision in this Plan to 
          the contrary, but subject to the Plan's coordination 
          of benefits rules and the exception set forth below, 
          this Plan does not pay otherwise covered charges 
          incurred for treatment of any illness or injury which 
          is or, in the opinion of the Trustees, likely to be-
          come the subject of a claim by or on behalf of the 
          covered person against any person or plan, whether 
          by civil lawsuit or otherwise.  Benefits may be con-
          ditionally covered and paid in this circumstance, 

                                  7

<PAGE>   21

          solely at the discretion of the Trustees, but in 
          that case the covered person agrees, by accepting 
          such payment (whether made to or on behalf of the 
          covered person) and in consideration of the Plan's 
          conditional payment, to reimburse the Plan, to the 
          extent of the Plan's payment, from any monies paid 
          to or on behalf of the covered person by any other 
          person or plan as compensation for the Illness or 
          Injury. 

     5)   In addition to the foregoing the Trustees may, as 
          a condition of making the payments described in the 
          preceding paragraph, require the covered person or 
          his representative to sign a subrogation agreement 
          reflecting (a) the covered person's obligation to 
          reimburse the Plan, (b) assignment to the Plan all 
          rights, claims or causes of action such covered 
          person (or any person or entity acting on his behalf) 
          has against any plan or person to the extent of bene-
          fits paid or payable under the Plan, (c) authorizing 
          (but not requiring) the Plan to sue, enforce, com-
          promise or settle (in such covered person's name or 
          otherwise) all such rights, claims or causes of action, 
          and (d) warranting that such covered person (and any 
          person or entity acting on his behalf) has not settled, 
          discharged or released any such right, claim or cause 
          of action against any person or plan, and shall not 
          do so.  In such event the agreement shall operate to 
          the same extent as the agreement described in the 
          preceding subsection.  The execution of such a sub-
          rogation agreement by or on behalf of the covered 
          person shall not, however, bind the Plan to make the 
          conditional payments described in the preceding para-
          graph.

     6)   The covered person (and any person or entity acting 
          on his behalf) shall hold in trust for the benefit 
          of the Plan (a) any amounts recovered to the extent 
          of benefits paid by the Plan and (b) all rights of 
          recovery against any person or plan by reason of the 
          Illness or Injury which occasioned the payment of 
          benefits under the Plan and, upon receipt of amounts 
          paid by another person or plan the covered person 
          shall immediately notify the Plan and pay to the Plan 
          all amounts due the Plan. Failure to make such reim-
          bursement shall entitle the Plan to sue the covered 
          person or, as applicable, his heirs, guardians, exe-
          cutor, or other representative in order to recover 
          the amounts due the Plan under these subrogation and 
          reimbursement provisions, and where in that case the 
          Plan is successful in whole or in part the Plan shall 
          also be entitled to reimbursement from the covered 
          person of all costs of collection, including reason-
          able attorneys fees.

     7)   Where this Plan is entitled to reimbursement pursuant 
          to these subrogation provisions and the covered person 
          fails or refuses to provide complete reimbursement, 
          in addition to any other remedies the Plan may have 
          under the plan or otherwise the Plan may terminate 
          coverage of the covered person with respect to pending 
          and future claims, and may set-off the reimbursement 

                                  8

<PAGE>   22

          due the Plan against claims, whether related or unre-
          lated to the injury or illness giving rise to this 
          Plan's reimbursement rights, payable by the Plan to 
          or on behalf of the covered person and any covered 
          member of the covered person's family. 

     8)   This Plan shall not be responsible for any costs or 
          expenses, including but not limited to attorneys fees, 
          incurred by or on behalf of a covered person in con-
          nection with any recovery from any other person or 
          plan unless this Plan so agrees in writing to pay a 
          part of these expenses. 

     9)   Upon written notification to such covered person, 
          the Plan may (but shall not be required to) directly 
          collect any claim the covered person (or any person 
          or entity acting on his behalf) may have against 
          any person or plan relating to the Illness or Injury 
          which occasioned the payment of benefits under the 
          Plan in any manner decided by the Trustees and with-
          out such covered person's consent or the consent of 
          any person or entity acting on behalf of such person; 
          any monies so recovered shall first be applied to 
          the Plan's reasonable collection costs and expenses 
          (including attorneys' fees), then to payments made 
          under this Plan, with any remaining balance to be 
          paid to or on behalf of the covered person as soon 
          as administratively practicable.

     10)  In any collection effort by the Plan under Paragraph 
          9) above, or with respect to any claim for reimburse-
          ment from the covered person or any person acting on 
          his behalf, the Trustees may agree to recover less 
          than the full amount of reimbursement if the Trustees 
          determine in their discretion that the Plan has made, 
          or caused to be made, such reasonable collection ef-
          forts as are appropriate under the circumstances and 
          the terms of such agreement are reasonable under the 
          circumstances, based upon the likelihood of collec-
          ting such amounts in full or the approximate expenses 
          the Plan would incur in an attempt to collect such 
          amounts.  The Trustees within their sole discretion 
          shall determine which of the Plan's rights and reme-
          dies is in the Plan's best interests and may take 
          such action against any person or plan as they deter-
          mine to be appropriate under the circumstances, fur-
          ther provided that any failure by the Plan, its 
          Trustees or its agents to exercise any right under 
          these subrogation provisions, and the reimbursement 
          and recovery provisions which follow hereafter, shall 
          not constitute a waiver of such right or affect the 
          parties' rights and obligations hereunder unless ex-
          pressly agreed thereto in writing by the Trustees.

     11)  A covered person (and anyone acting on behalf of the 
          covered person) has a duty to cooperate with this 
          Plan and, at the request of the Trustees or their 
          designee, to take any action, give information and 
          assistance, and execute such documents as are deemed 
          by the Trustees necessary to enforce the Plan's rights 

                                  9

<PAGE>   23

          under these subrogation provisions and the reimburse-
          ment and recovery provisions which follow hereafter. 
          The Plan will make no payments to a covered person 
          or on a covered person's behalf until the Trustees 
          are satisfied that the covered person has complied 
          with the requirements of this subsection.  The Trus-
          tees or their designee, without the consent of or 
          notice to any person, may release to or obtain from 
          any person any information, with respect to any per-
          son, which the Trustees or their designee deem neces-
          sary to implement these provisions. 

     12)  The covered person, or anyone acting on his behalf, 
          shall take no action to prejudice the subrogation 
          or reimbursement rights of this Plan, and shall not 
          settle or compromise any claim against any person or 
          plan, where this Plan is subrogated with respect to 
          monies payable to or on behalf of the covered person 
          by such person or plan, without the express, written 
          consent of the Trustees or their designee.  Where 
          the Trustees determine that the covered person, or 
          anyone acting on behalf of the covered person, has 
          in the opinion of the Trustees so prejudiced the 
          Plan's rights, the provisions of Paragraphs 6) and 
          7) above shall apply as though the covered person 
          had received payment of amounts up to the extent 
          of the Plan's subrogation interest.

     REIMBURSEMENT AND RECOVERY

     1)   Whenever this Plan makes payments which, together 
          with the payments the covered person has received or 
          is entitled to receive from any other plan or person,

          (a)  exceed the maximum amount necessary to satisfy 
               the intent of this Plan's subrogation and reim-
               bursement rules or the Plan's coordination of 
               benefits provisions; or

          (b)  exceed, under the terms of the Plan, the bene-
               fits properly payable to the person or plan to 
               or for or with respect to whom the payments 
               were made,

          the Trustees shall have the right to recover such 
          payments, to the extent of such excess, from among 
          one or more of the following, as the Trustees shall 
          determine:  any person to whom or on whose behalf 
          such payments were made, any other covered person 
          who is a member of the family of the person to whom 
          or on whose behalf the Plan made payment, any insur-
          ance companies, or any other organizations.  Alter-
          natively, the Trustees may set-off the amount of 
          such payments, to the extent of such excess, against 
          any amount owing, at that time or in the future, to 
          one or more of the following, as the Trustees shall 
          determine:  any person to whom or on whose behalf 

                                  10

<PAGE>   24

          such payments were made, any other covered person 
          who is a member of the family of the person to whom 
          or on whose behalf the Plan made payment, any insur-
          ance companies, or any other organizations.

     2)   For example, but not by way of limitation, if this 
          Plan pays a claim submitted by a covered person or 
          a health care provider who treated the covered person, 
          and the Trustees later determine that the claim was 
          for an expense not covered under this Plan, then the 
          Trustees are entitled to recover the payment from 
          the covered person, a covered member of the person's 
          family, or the provider, or to recover part of the 
          payment from the covered person (or a covered member 
          of his family) and part from the provider, or the 
          Trustees may set-off the amount of the payment from 
          amounts the Plan owes in the future to the covered 
          person (or a covered member of the person's family) 
          or the provider, or both.  This same rule applies if 
          the Plan makes payment to or on behalf of a covered 
          person or a provider of an expense which is a covered 
          expense, but the amount paid exceeds the amount re-
          quired to be paid under the Plan.

     3)   These reimbursement provisions also apply where this 
          Plan makes payment of an allowable expense incurred 
          for treatment of an illness or injury for which 
          another person or plan is or may be liable, and where 
          the Plan's subrogation provisions do not provide the 
          Plan with a right to recover the amounts the Plan 
          pays for treatment of the illness or injury.  If the 
          other person or plan makes payment to the covered 
          person or on the covered person's behalf as compen-
          sation for the illness or injury, and this Plan is 
          not subrogated with respect to the payment, this 
          Plan is entitled to reimbursement from the covered 
          person (or the person who received such payment on 
          behalf of the covered person) in an amount equal 
          to the lesser of the benefits paid by this Plan for 
          treatment of the injury or illness, or the amount 
          paid to the covered person or on the covered per-
          son's behalf by the other person or its insurer. 
          This provision shall not apply where the other per-
          son or its insurer is a medical plan with respect 
          to which this Plan, pursuant to its coordination 
          of benefits provisions, is the primary payer of the 
          covered person's allowable expenses.  Paragraphs 6) 
          and 7) of the Plan's subrogation provisions above, 
          regarding the covered person's duty to make reim-
          bursement, and the Plan's rights and remedies if he 
          does not, are incorporated by reference herein.

     4)   In addition, where another person or plan pays 
          compensation to or on behalf of a covered person 
          for an illness or injury, and the covered person 
          incurs (either before or after payment of such com-
          pensation) otherwise covered charges for treatment 
          of the illness or injury, a special rule applies. 
          In that case, such otherwise covered charges which 
          were incurred after the date on which the compensa-
          tion was paid, or which were incurred prior to such 

                                  11

<PAGE>   25

          date but not paid by this Plan as of such date, 
          shall be excluded to the extent of the excess (if 
          any) of the compensation paid to or on behalf of 
          the covered person over the covered charges which 
          the Plan has already paid for treatment of the ill-
          ness or injury.

     5)   This Plan shall not be responsible for any costs or 
          expenses incurred by or on behalf of a covered person 
          in connection with any recovery or reimbursement from 
          any other plan or person unless this Plan agrees in 
          writing to pay a part of those expenses.  The charac-
          terization of any amounts paid to or on behalf of a 
          covered person, whether under a settlement agreement, 
          judgment, "plan" as defined in Paragraph 2 of the 
          Plan's subrogation provisions above, or otherwise, 
          shall not affect this Plan's right to reimbursement 
          and to characterize otherwise covered charges as ex-
          cludable charges pursuant to the provisions of these 
          reimbursement and recovery provisions. 

     CONDITIONAL PAYMENTS IN CASE OF WRONGFUL DEATH

     1)   Where a covered person dies as a result of the Injury 
          or Illness, and another covered person, in the judg-
          ment of the Trustees, has as a result of such death 
          a cause of action for the deceased person's wrongful 
          death, the otherwise covered expenses incurred by or 
          on behalf of the deceased person prior to his death 
          shall not be considered covered expenses under this 
          Plan. However, such expenses may nevertheless be 
          treated as conditionally covered expenses and be 
          paid in this circumstance, solely at the discretion 
          of the Trustees, but in that case the covered person 
          with the cause of action agrees, in consideration 
          of the Plan's payment of such expenses, to reimburse 
          the Plan, to the extent of the Plan's payment, from 
          any monies paid to such covered person by any other 
          person or plan as compensation for the deceased per-
          son's death.  Failure to make such reimbursement shall 
          entitle the Plan to sue the covered person or, as 
          applicable, his heirs, guardians, executor, or other 
          representative in order to recover the amounts due 
          the Plan under this provision, and where in that case 
          the Plan is successful in whole or in part the Plan 
          shall also be entitled to reimbursement from the 
          covered person of all costs of collection, including 
          reasonable attorneys fees.

     2)   In addition to the foregoing the Trustees may, as a 
          condition of making the conditional payments des-
          cribed in the preceding paragraph, require the covered 
          person with the cause of action to sign a subrogation 
          or reimbursement agreement reflecting the covered 
          person's obligation to reimburse the Plan, and in such 
          event the agreement shall operate to the same extent 
          as the agreement described in the preceding subsection. 
          The execution of such a subrogation agreement by such 
          covered person shall not, however, bind the Plan to 
          make the conditional payments described in the prece-
          ding paragraph.

                                  12

<PAGE>   26

     3)   Where this Plan makes the conditional payments des-
          cribed above and the covered person with the cause of 
          action elects not to pursue the cause of action, but 
          some other person related to the deceased person pur-
          sues the cause of action and recovers monies from the 
          person or plan who is or may be responsible for the 
          deceased person's wrongful death, this Plan is never-
          theless entitled to reimbursement from the covered 
          person.  If the covered person fails or refuses to 
          provide complete reimbursement, in addition to any 
          other remedies the Plan may have, under the Plan or 
          otherwise, the Plan may terminate coverage of the 
          covered person with respect to pending and future 
          claims, or may set-off the reimbursement due the 
          Plan against claims, whether related or unrelated 
          to the injury or illness giving rise to this Plan's 
          reimbursement rights, payable by the Plan to or on 
          behalf of the covered person and any covered member 
          of the covered person's family, or the Plan may do 
          both of these things.

     DETERMINATION OF BENEFITS UNDER SUBROGATION AND REIMBURSE-
     MENT PROVISIONS

     The amount of benefits, if any, payable under the Plan 
     pursuant to the preceding provisions concerning subroga-
     tion and reimbursement shall be determined in accordance 
     with the provisions of paragraph (1) and (2) of the Sec-
     tion entitled BENEFIT DETERMINATION of the COORDINATION 
     OF BENEFITS AND EXCESS COVERAGE PROVISION of the Plan as 
     if the proceeds of the settlement, judgment or Insurance 
     Policy were benefits payable under another Plan (that is, 
     the sum of the benefits payable under this Plan and the 
     proceeds of the settlement or judgment shall not exceed 
     the Allowable Expenses incurred by the covered individual 
     during the Benefit Determination Period).

25.  Subparagraph (c) of Paragraph 23) of the Subsection entitled MED-
     ICAL LIMITATIONS AND EXCLUSIONS of Section C MEDICAL CARE COVE-
     AGE of Article III Benefits is deleted and replaced by the fol-
     lowing.

     (c)  if the drug, device, medical treatment or procedure 
          is the subject of an ongoing Phase I or Phase II 
          clinical trial, is the research, experimental, study 
          or investigational arm of ongoing Phase III clinical 
          trials, or is otherwise under study to determine its 
          maximum tolerated dose, its toxicity, its safety, 
          its efficacy or how any of these factors compares 
          with standard means of treatment or diagnosis; or

26.  The words "on account of" in the parenthetical expression in the 
     third sentence of the Section entitled BENEFIT AMOUNT of Section 
     B WEEKLY DISABILITY INCOME COVERAGE of Article III Benefits are 
     deleted and replaced by the words "attributable to".

                                  13

<PAGE>   27

27.  Paragraph 8) of the Subsection entitled MEDICAL LIMITATIONS AND 
     EXCLUSIONS of Section C MEDICAL CARE COVERAGE of Article III 
     Benefits is deleted and replaced by the following:

     8)   Cosmetic surgery or other medical care for cosmetic 
          purposes, except for (a) medical care and treatment 
          for Injuries sustained in an accident, (b) medical 
          care and treatment for the correction of an abnormal 
          congenital condition, and (c) reconstructive surgery 
          to correct a defect caused by prior surgery performed 
          for treatment of an Illness;

28.  The following sentences are added at the end of paragraph 1. IN-
     PATIENT HOSPITALIZATION of the Subsection entitled UTILIZATION 
     REVIEW REQUIREMENT of Section C MEDICAL CARE COVERAGE of Article 
     III Benefits.

     However, the Plan will not restrict benefits for any Hos-
     pital stay in connection with childbirth for the mother 
     or newborn Child following a normal vaginal delivery to 
     less than forty-eight (48) hours, or to less than ninety-
     six (96) hours in the case of a Cesarean section.  In 
     addition, the Plan will not require a provider to obtain 
     authorization or precertification for prescribing the 
     minimum lengths of stay described above.

29.  Paragraph 1) of the Section entitled DEFINITIONS of Article II 
     Eligibility Provisions is deleted and replaced by the following.

     1)   "Employer" means Paul Mueller Company and any member 
          of Paul Mueller Company's controlled group (as de-
          fined by the Internal Revenue Code) that adopts the
          Plan with the consent of the Trustees.

30.  Paragraph 2) of the Section entitled DEFINITIONS of Article II 
     Eligibility Provisions is deleted and replaced by the following.

     2)   "Eligible Employee" means a permanent employee of 
          the Employer who is performing Active Work on a Full-
          Time Basis, except that bargaining unit employees 
          of Mueller Field Operations, Inc. are not Eligible 
          Employees unless so provided in a collective bargain-
          ing agreement between Mueller Field Operations, Inc. 
          and a collective bargaining representative.

31.	The second paragraph of Article IV Named Fiduciaries is deleted 
     and replaced by the following:

     Paul Mueller Company shall serve as Administrator of 
     the Plan for purposes of ERISA.  As Administrator, Paul 
     Mueller Company shall perform the following duties: 

                                  14

<PAGE>   28

32.  The second sentence of Article VI Amendment and Termination of 
     Plan is deleted and replaced by the following:

     The Plan may be terminated by action of the Board of 
     Directors of Paul Mueller Company in accordance with the 
     provisions of the Declaration of Trust.

33.  The words "or through an administrative process having the force 
     and effect of law" are inserted between the words "jurisdiction" 
     and "for" in the fourth line of paragraph 7) of the Section en-
     titled DEFINITIONS of Article II Eligibility Provisions.

34.  The last sentence of the Subsection entitled MEDICAL EXPENSE 
     BENEFITS of Section C MEDICAL CARE COVERAGE of Article III Bene-
     fits is deleted and replaced by the following:

     If (a) the Plan has entered into a contract with a Pre-
     ferred Provider Organization (PPO) and (b) the charges 
     negotiated by the PPO exceed the provider's usual charges 
     and (c) the Covered Individual is responsible for payment 
     of that excess, the Plan will pay the benefits described 
     in the preceding sentence plus 100% of the amount by which 
     the negotiated charge exceeds the provider's usual charge.

35.  The words "(for example, because the pregnancy is a preexisting 
     condition)" are deleted from the Subsection entitled FLAT RATE 
     MATERNITY of Section C MEDICAL CARE COVERAGE of Article III Bene-
     fits.

36.  The first sentence of the last paragraph of item U) of the Sub-
     section entitled MEDICAL COVERED CHARGES of Section C MEDICAL 
     CARE COVERAGE of Article III Benefits is deleted and replaced by 
     the following:

     Covered Individuals must contact the Administrative Mana-
     ger before undergoing any organ transplant procedure.

37.  The words "occurring while covered under the Plan" are deleted 
     from Paragraph 13 of the Subsection entitled MEDICAL LIMITATIONS 
     AND EXCLUSIONS of Section C MEDICAL CARE COVERAGE of Article III 
     Benefits.

38.  The words "or Participant" are inserted between the words "Bene-
     ficiary" and "must" in the first line of the fifth paragraph of 
     the Section entitled CONTINUATION COVERAGE of Article II Eligi-
     bility Provisions.

39.  The words "although the term "Physician" does not include Social 
     Workers or Licensed Professional Counselors, services rendered by 
     such practitioners are covered under the Plan when they are an 
     integral part of, rendered at and billed by a mental illness or 
     chemical dependency treatment program of a Hospital, a Residen-
     tial Treatment Program or a Nonresidential Treatment Program" in 

                                  15

<PAGE>   29

     Paragraph 2) of the Subsection entitled MEDICAL CARE DEFINITIONS 
     of Section C MEDICAL CARE COVERAGE of Article III Benefits are 
     deleted and replaced by the words "although the term "Physician" 
     does not ordinarily include social workers or licensed profes-
     sional counselors, services rendered by Licensed Clinical Social 
     Workers and Licensed Professional Counselors are covered under 
     the Plan when they are (a) an integral part of, rendered at, and 
     billed by a mental illness or chemical dependency treatment pro-
     gram of a Hospital, a Residential Treatment Program, or a Nonre-
     sidential Treatment Program, (b) an integral part of a treatment 
     program approved by the Plan's Employee Assistance Program, or 
     (c) rendered pursuant to and within the scope of a referral made 
     by the Plan's Employee Assistance Program."

40.  The following paragraphs 22) and 23) are added to the Subsection 
     entitled MEDICAL CARE DEFINITIONS of Section C MEDICAL CARE COV-
     ERAGE of Article III Benefits.

     22)  "Licensed Clinical Social Worker" means a person who 
          (a) is trained and experienced as a clinical social 
          worker and who holds a current, valid license to 
          practice as a clinical social worker in the state 
          in which he practices or (b) is a graduate of an 
          accredited school of social work and meets all re-
          quirements for licensure as a clinical social worker.

     23)  "Licensed Professional Counselor" means a person who 
          (a) is registered, certified or licensed as a profes-
          sional counselor by the state in which he practices 
          or (b) is a graduate of an accredited educational 
          institution with at least a master's degree with a 
          major in counseling or its equivalent, meets all 
          requirements for certification or licensure as a pro-
          fessional counselor other than the requirement of 
          supervised counseling experience and who is supervised 
          by a person who meets the requirements of (a) above.

41.  The following Subsection is added following the Subsection enti-
     tled HIGH RISK PREGNANCY BENEFIT of Section C MEDICAL CARE COVER-
     AGE of Article III Benefits.

     EMPLOYEE ASSISTANCE PROGRAM
     The Trustees may contract with an Employee Assistance 
     Program (EAP) to provide short-term counseling to assist 
     employees and dependents with personal problems, including:

     -    Family Problems
     -    Marital Problems
     -    Emotional Difficulties
     -    Stress and Anxiety
     -    Alcoholism
     -    Drug Abuse
     -    Legal Problems
     -    Financial Problems

                                  16

<PAGE>   30

     The EAP shall provide an assessment interview and up to 
     five (5) counseling sessions at no cost to Covered Indi-
     viduals.  In addition, the EAP may refer Covered Indivi-
     duals to outside Psychiatrists, Clinical Psychologists, 
     Licensed Clinical Social Workers and Licensed Professional 
     Counselors.  A portion of the fees charged by these pro-
     fessionals may be covered under other provisions of the 
     Plan.  The EAP may also refer Covered Individuals to other 
     community resources which charge no fees or reduced fees 
     based on the Covered Individual's ability to pay.

     Use of the EAP shall be confidential.  Information shall 
     not be released to the Employer without the Covered Indi-
     vidual's permission.

42.  The following Paragraph W) is added to the Subsection entitled 
     MEDICAL COVERED CHARGES of Section C MEDICAL CARE COVERAGE of Ar-
     ticle III Benefits.

     W)   Charges for the following services and supplies for 
          smoking cessation, up to a lifetime maximum of $200 
          per Covered Individual.

          -    Group or individual counseling provided by medi-
               cal professionals;
          -    Hypnotherapy provided by a licensed hypnothera-
               pist;
          -    Pharmaceutical aids, including prescription anti-
               depressants (Zyban and Wellbutrin), nicotine 
               patches (Nicoderm CQ or Nicotrol), nicotine gum 
               (Nicorette) and nicotine nasal sprays.

43.  The words "described in Paragraphs P, Q and T" in exception (b) 
     of the Subsection entitled MEDICAL EXPENSE BENEFIT of Section C 
     MEDICAL CARE COVERAGE of Article III Benefits are deleted and 
     replaced by the words "described in Paragraphs P, Q, T and W".

44.  The following paragraph is added at the end of the Subsection 
     entitled MAXIMUM AMOUNTS of Section C MEDICAL CARE COVERAGE of 
     Article III Benefits.

     Refer to Paragraph W) of the section entitled COVERED 
     MEDICAL CHARGES in this Part C for the $200 smoking ces-
     sation maximum.

45.  Paragraph 16) of the Subsection entitled MEDICAL LIMITATIONS AND 
     EXCLUSIONS of Section C MEDICAL CARE COVERAGE of Article III 
     Benefits is deleted and replaced by the following.

     16)  Treatment of tobacco dependency, except smoking ces-
          sation services to the extent covered under Paragraph 
          W) of the section entitled MEDICAL COVERED CHARGES in 
          this Part C.

46.  The last subparagraph of Paragraph P) of the Subsection entitled 

                                  17

<PAGE>   31

     MEDICAL COVERED CHARGES of Section C MEDICAL CARE COVERAGE of Ar-
     ticle III Benefits is deleted and replaced by the following.

     The foregoing frequency limits are not applicable (a) to 
     persons with a family history of breast cancer or (b) to 
     mammograms recommended by a Physician following a prior 
     mammogram which showed tissue changes.

47.  The last sentence of Paragraph 4)d) of the Section entitled DEFI-
     NITIONS of Article II Eligibility Provisions is deleted and re-
     placed by the following.

     See paragraph 7 of this section for a definition of the 
     phrase "medical child support order."

48.  The words "Treatment of alcoholism" in Paragraph M) of the Sub-
     section entitled MEDICAL COVERED CHARGES of Section C MEDICAL 
     CARE COVERAGE of Article III Benefits are changed to "Charges for 
     treatment of alcoholism".

49.  The words "Cardiac rehabilitation services" in Paragraph V) of 
     the Subsection entitled MEDICAL COVERED CHARGES of Section C 
     MEDICAL CARE COVERAGE of Article III Benefits are changed to 
     "Charges for cardiac rehabilitation services".

50.  The words "Routine Prostate Specific Antigen (PSA) tests" in Pa-
     ragraph T) of the Subsection entitled MEDICAL COVERED CHARGES 
     of Section C MEDICAL CARE COVERAGE of Article III Benefits are 
     changed to "Charges for Routine Prostate Specific Antigen (PSA) 
     tests".

51.  Paragraph O) of the Subsection entitled MEDICAL COVERED CHARGES 
     of Section C MEDICAL CARE COVERAGE of Article III Benefits is 
     deleted and replaced by the following.

     Charges for services rendered by a chiropractor practicing 
     within the scope of his profession.  Covered Expense for 
     chiropractic services is limited to $500 for each Covered 
     Individual each calendar year.

52.  The following Paragraph 27) is added to the Subsection entitled 
     MEDICAL LIMITATIONS AND EXCLUSIONS of Section C MEDICAL CARE COV-
     ERAGE of Article III Benefits.

     27)  Medication used to treat erectile dysfunction or im-
          potency in excess of six (6) doses in any one month. 
          This includes all dosage forms of such medication. 
          Medications for which coverage is limited by this 
          paragraph include, but are not limited to, Viagra, 
          Caverject and Muse.

     Item 41 above is effective October 1, 1996.  Items 4, 5, 6 and 34 
above are effective with respect to charges incurred on or after Janu-
ary 1, 1997.  Items 3, 12, 13, 14, 15, 16, 17, 18, 19 and 25 above are 
effective with respect to charges incurred on or after July 1, 1997. 

                                  18

<PAGE>   32

Item 11 above is effective with respect to (a) Covered Individuals 
whose Medicare entitlement commences after August 5, 1997 and (b) 
Covered Individuals whose Medicare entitlement commenced on or before 
August 5, 1997 and with respect to whom the Plan was still the primary 
payer on August 5, 1997.  Items 1, 2, 7, 8, 9, 10, 24, 27, 28, 35, 36, 
37, 39, 40, 42, 43, 44, 45, 46, 47, 48, 49, 50 and 51 above are effec-
tive with respect to charges incurred on and after January 1, 1998.  
Items 22, 23 and 26 above are effective with respect to disabilities 
commencing on or after October 1, 1997.  Items 20 and 21 above are 
effective with respect to persons retiring on or after October 1, 
1997. Items 29, 30, 31, 32, 33 and 38 above are effective January 1, 
1998.  Item 52 above is effective with respect to charges incurred on 
and after July 1, 1998.

     IN WITNESS WHEREOF, the Trustees of the PAUL MUELLER COMPANY EM-
PLOYEE BENEFIT PLAN have caused this Fourth Amendment to be duly exe-
cuted this 5th day of June, 1998.

By:   /S/ DONALD E. GOLIK              By:   /S/ GERALD S. MILLER
    --------------------------             --------------------------
    Donald E. Golik - Trustee              Gerald S. Miller - Trustee

By:   /S/ MICHAEL W. YOUNG              By:   /S/ GAIL HENRICHS
    --------------------------             --------------------------
    Michael W. Young - Trustee             Gail Hendichs - Trustee

                                  19