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                  UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                             WASHINGTON, D.C. 20460

                                  JUN 22 1998
Mirenco Inc.                                                   OFFICE OF
Mr. Dwayne Fosseen                                          AIR AND RADIATION
President
P.O. Box 343 (206 May Street)
Radcliffe, IA 50230

Dear MR. FOSSEEN:

     Pursuant to your June 17, 1998  notification,  the following  fuel additive
has  been  registered  per 40 CFR  79.23  (our  internal  identification  number
precedes the name):

1761-0001           HYDROFIRE Fluid

     Note that per 40 CFR 79.21(f) you would be required to notify us in writing
if certain  information in your notification were to change. In addition,  note,
that with your  notification,  you have  provided  assurances  that you will not
represent,  directly or indirectly,  in any notice,  circular,  letter, or other
written  communication,  or any  written,  oral,  or  pictoral  notice  or other
announcement in any publication or by radio or television,  that registration of
this additive constitutes endorsement,  certification, or approval by any agency
of the United States.

     Please call (202) 564-9836 if you have any questions.

                                        Sincerely

                                        /s/ Deborah K Wood
                                        ------------------
                                        Deborah K. Wood
                                        Acting Director
                                        Fuels and Energy Division