SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                                  Form 8-K/A

               Current Report Pursuant to Section 13 or 15(d) of
                      The Securities Exchange Act of 1934

     Date of Report (Date of earliest event reported): September 30, 1999

                                THERMATRIX INC.
              (Exact Name of Registrant as Specified in Charter)


                                                                 
          Delaware                            0-20819                              94-2958515
- -------------------------------       ------------------------         ------------------------------------
(State or Other Jurisdiction of       (Commission File Number)         (I.R.S. Employer Identification No.)
        Incorporation)



                        308 North Peters Road, Suite 100
                           Knoxville, Tennessee 37922
          (Address of principal executive offices, including zip code)

                                 (423) 539-9603
              (Registrant's telephone number, including area code)



                         2025 Gateway Place, Suite 132
                           San Jose, California 95110
                                (Former address)


Item 4.    Changes in Registrant's Certifying Accountant

On August 31, 1999 the Registrant issued a press release announcing that it was
closing its offices in San Jose, California to complete the transfer of its
corporate headquarters to Knoxville, Tennessee.  The primary reason for this
move was to be more conveniently situated to support its expanding operations in
Europe, particularly those in the United Kingdom.

Effective September 30, 1999 Arthur Andersen LLP of San Jose, California
resigned as the Registrant's independent public accountants. Arthur Andersen LLP
qualified its report on the financial statements of the Registrant for the year
ended December 31, 1998 with a "going concern" opinion. For the year ended
December 31, 1997, Arthur Andersen LLP's report on the financial statements of
the Registrant was unqualified.  There have been no disagreements regarding any
matter of accounting principles or practices, financial statement disclosure or
auditing scope or procedure between the Registrant and Arthur Andersen LLP.
There have been no reportable events between Arthur Andersen LLP and the
Registrant.

The Audit Committee of the Board of Directors approved the resignation of Arthur
Andersen LLP as the Registrant's independent public accountants.

The Registrant is currently seeking a firm more convenient to its Knoxville,
Tennessee offices to serve as independent public accountant and intends to have
a successor firm engaged as soon as possible, but no later than December 31,
1999, the end of its fiscal year.


Item 7.    FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION AND EXHIBITS

(c)  Exhibits

4-1   Letter from Arthur Andersen LLP dated October 7, 1999.


                                  SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                    THERMATRIX INC.

Dated:  October 15, 1999            By:  /s/ Daniel S. Tedone
                                         ---------------------------
                                         Daniel S. Tedone, Executive
                                         Vice President and Chief
                                         Financial Officer