Document:

EXHIBIT 10.21

                             PROMISSORY DEMAND NOTE

$30,000                                                     SEPTEMBER  12,  2003

     FOR  VALUE RECEIVED, H.E.R.C. PRODUCTS INCORPORATED, a Delaware Corporation
("Maker"), promises to pay to S. STEVEN CARL ("Holder"), or order, the principal
sum  of  Thirty Thousand Dollars ($30,000), together with interest on the unpaid
portion thereof from date until paid at the rate of eight percent (8%) per annum
from  September  12,  2003,  on  demand,  as  follows:

     Maker  shall  make payment in lawful money of the United States of America.

     This  Note  may  be  prepaid  in  whole or in part, without penalty, at the
option  of  Maker  and  without  the  consent  of  Holder.

     This  Note is nonrecourse as to Maker and is made without the pledge of any
security  interest  in  the  property,  realty  or  personalty,  of  Maker.

     The  Maker  agrees that in case of the event of default in payment of this
Note, and  it is placed in the hands of an attorney for collection, or suit is
Brought on  the  same,  or  same is collected through Probate or Bankruptcy
proceedings, then  an additional amount of ten percent (10%) on the principal
and interest of this  Note  shall  be  added  to  the  same as collection fees.

     The  laws  of  the  State  of Virginia excluding its conflict of laws rules
shall govern this Note. The exclusive jurisdiction and venue of any legal action
instituted  by  any  party  to  this  Note  shall  be  Norfolk,  Virginia.

     MAKER:

I.     H.E.R.C.  PRODUCTS  INCORPORATED
     (a  Delaware  Corporation)

     By:      /s/  John  A.  Gulick  III
          ------------------------------
          John  A.  Gulick  III
          Vice  President-Office  of  General  Counsel

     HOLDER:

     S.  STEVEN  CARL

        /s/  S.  Steven  Carl
     ------------------------

<PAGE>EXHIBIT 10.22

                             PROMISSORY DEMAND NOTE

$50,000                                                       DECEMBER  2,  2003

     FOR  VALUE RECEIVED, H.E.R.C. PRODUCTS INCORPORATED, a Delaware Corporation
("Maker"), promises to pay to S. STEVEN CARL ("Holder"), or order, the principal
sum  of  Fifty  Thousand Dollars ($50,000), together with interest on the unpaid
portion thereof from date until paid at the rate of eight percent (8%) per annum
from  December  2,  2003,  on  demand,  as  follows:

     Maker  shall  make payment in lawful money of the United States of America.

     This  Note  may  be  prepaid  in  whole or in part, without penalty, at the
option  of  Maker  and  without  the  consent  of  Holder.

     This  Note is nonrecourse as to Maker and is made without the pledge of any
security  interest  in  the  property,  realty  or  personalty,  of  Maker.

The  Maker  agrees that in case of the event of default in payment of this Note,
and  it is placed in the hands of an attorney for collection, or suit is brought
on  the  same,  or  same is collected through Probate or Bankruptcy proceedings,
then  an additional amount of ten percent (10%) on the principal and interest of
this  Note  shall  be  added  to  the  same  as  collection  fees.

     The  laws  of  the  State  of Virginia excluding its conflict of laws rules
shall govern this Note. The exclusive jurisdiction and venue of any legal action
instituted  by  any  party  to  this  Note  shall  be  Norfolk,  Virginia.

     MAKER:

II.     H.E.R.C.  PRODUCTS  INCORPORATED
     (a  Delaware  Corporation)

     By:     /s/  John  A.  Gulick  III
          -----------------------------
          John  A.  Gulick  III
          Vice  President-Office  of  General  Counsel

     HOLDER:

     S.  STEVEN  CARL

       /s/  S.  Steven  Carl
     -----------------------

<PAGE>EXHIBIT 10.23

                              PROMISSORY TERM NOTE

$50,000                                                      DECEMBER  08,  2003

     FOR  VALUE RECEIVED, H.E.R.C. PRODUCTS INCORPORATED, a Delaware Corporation
("Maker"),  promises  to  pay  to  R.  JOHN  ARMSTRONG ("Holder"), or order, the
principal sum of Fifty Thousand Dollars ($50,000), together with interest on the
                 --------------------------------
unpaid  portion  thereof  from date until paid at the rate of eight percent (8%)
per  annum  from  December  08,  2003,  on  or  before June 8, 2004, as follows:
                  -------------------                  ------------

     Maker  shall  make payment in lawful money of the United States of America.

     This  Note  may  be  prepaid  in  whole or in part, without penalty, at the
option  of  Maker  and  without  the  consent  of  Holder.

     This  Note is nonrecourse as to Maker and is made without the pledge of any
security  interest  in  the  property,  realty  or  personalty,  of  Maker.

This  note  may  be  renewed  or  extended under terms agreed to by the parties.

The  Maker  agrees that in case of the event of default in payment of this Note,
and  it is placed in the hands of an attorney for collection, or suit is brought
on  the  same,  or  same is collected through Probate or Bankruptcy proceedings,
then  an additional amount of ten percent (10%) on the principal and interest of
this  Note  shall  be  added  to  the  same  as  collection  fees.

     The  laws  of  the  State  of Virginia excluding its conflict of laws rules
shall govern this Note. The exclusive jurisdiction and venue of any legal action
instituted  by  any  party  to  this  Note  shall  be  Norfolk,  Virginia.

     MAKER:

III.     H.E.R.C.  PRODUCTS  INCORPORATED
     (a  Delaware  Corporation)

     By:     /s/  S.  Steven  Carl
          ------------------------
          S.  Steven  Carl
          Chief  Executive  Officer

     HOLDER:

     R.  JOHN  ARMSTRONG

         /s/  R.  John  Armstrong
     ----------------------------

<PAGE>EXHIBIT 10.24

                              PROMISSORY TERM NOTE

$50,000                                                      DECEMBER  17,  2003

     FOR  VALUE RECEIVED, H.E.R.C. PRODUCTS INCORPORATED, a Delaware Corporation
("Maker"),  promises  to  pay  to  PAMELA L. AFFHOLDER ("Holder"), or order, the
principal sum of Fifty Thousand Dollars ($50,000), together with interest on the
                 --------------------------------
unpaid  portion  thereof  from date until paid at the rate of eight percent (8%)
per  annum  from  December  17,  2003,  on  or  before June 8, 2004, as follows:
                  -------------------                  ------------

     Maker  shall  make payment in lawful money of the United States of America.

     This  Note  may  be  prepaid  in  whole or in part, without penalty, at the
option  of  Maker  and  without  the  consent  of  Holder.

     This  Note is nonrecourse as to Maker and is made without the pledge of any
security  interest  in  the  property,  realty  or  personalty,  of  Maker.

This  note  may  be  renewed  or  extended under terms agreed to by the parties.

The  Maker  agrees that in case of the event of default in payment of this Note,
and  it is placed in the hands of an attorney for collection, or suit is brought
on  the  same,  or  same is collected through Probate or Bankruptcy proceedings,
then  an additional amount of ten percent (10%) on the principal and interest of
this  Note  shall  be  added  to  the  same  as  collection  fees.

     The  laws  of  the  State  of Virginia excluding its conflict of laws rules
shall govern this Note. The exclusive jurisdiction and venue of any legal action
instituted  by  any  party  to  this  Note  shall  be  Norfolk,  Virginia.

     MAKER:

IV.     H.E.R.C.  PRODUCTS  INCORPORATED
     (a  Delaware  Corporation)

     By:     /s/  S.  Steven  Carl
         -------------------------
          S.  Steven  Carl
          Chief  Executive  Officer

     HOLDER:

     PAMELA  L.  AFFHOLDER

        /s/  Pamela  L.  Affholder
     -----------------------------

<PAGE>EXHIBIT 10.25

                                      FIRST
                              RENEWAL AND EXTENSION
                                       OF
                                  INTEREST ONLY
                           NONRECOURSE PROMISSORY NOTE
                             AND SECURITY AGREEMENT

Original  Amount:  $400,000.00                       Renewal and Extension Date:
                                                     February  23,  2004
                                                     -------------------

     FOR VALUE RECEIVED, H.E.R.C. Products Incorporated, a Delaware corporation,
("Maker" or "Debtor") promises to pay to R. John Armstrong ("Holder" or "Secured
Party"),  or  order,  the  principal  sum  of  Four  Hundred  Thousand  Dollars
($400,000.00)  with  interest  from  the  date  of  the  original  Interest Only
Nonrecourse  Promissory  Note  and Security Agreement dated February 23, 2003 on
unpaid principal owing from time to time at the rate of eight percent (8.0%) per
annum  until fully paid pursuant to this First Renewal and Extension of Interest
Only  Nonrecourse  Promissory  Note  and  Security Agreement.   Maker shall make
interest  only  payments  on  the  first  day of each month from the date of the
original  Note dated February 23, 2003 until the date one (1) year from the date
of the original Note, as first extended and renewed hereunder ("Maturity Date").
Principal  plus  all  accrued and unpaid interest on such principal shall be due
and  payable  on  the  Maturity  Date.

     This  note  is delivered and accepted not in payment but for the purpose of
and  in  consideration  of  the  extension  of  time  of payment of the original
Interest  Only  Nonrecourse  Promissory  Note and Security Agreement. This First
Renewal  and Extension of Interest Only Nonrecourse Promissory Note and Security
Agreement  incorporates  by  specific  reference  that  certain  Interest  Only
Nonrecourse  Promissory  Note  and Security Agreement dated February 23, 2003 by
and between its Maker, H.E.R.C. Products Incorporated and its Holder and Secured
Party,  R.  John  Armstrong,  and  specifically  incorporates  all  the  terms,
conditions  and  secured  party  interests  stated  therein  as modified by this
renewal  and  extension.

     Executed  at  Portsmouth,  Virginia  the  day and year first above written.

MAKER/DEBTOR

H.E.R.C.  Products  Incorporated,
a  Delaware  corporation

By:    S.  Steven  Carl,  CEO
     ------------------------

[Signature]

  /s/  S.  Steven  Carl
-----------------------

<PAGE>

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