As filed with the Securities and Exchange Commission on November 12, 1998 Registration No. 33-77818 SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form S-3 Post-Effective Amendment No. 4 To Registration Statement Under The Securities Act of 1933 ThermoRetec Corporation (Exact name of registrant as specified in its charter) Delaware 59-3203761 (State or other jurisdiction of (IRS Employer Identification Number) incorporation or organization) 9 Pond Lane, Suite 5A Concord, Massachusetts 01742-2851 (978) 371-3200 (Address, including zip code, and telephone number, including area code, of registrant's principal executive offices) Sandra L. Lambert, Secretary ThermoRetec Corporation c/o Thermo Electron Corporation 81 Wyman Street P.O. Box 9046 Waltham, Massachusetts 02454-9046 (781) 622-1000 (Name, address, including zip code, and telephone number, including area code, of agent for service) Copies to: Seth H. Hoogasian, Esq. General Counsel ThermoRetec Corporation c/o Thermo Electron Corporation 81 Wyman Street P.O. Box 9046 Waltham, Massachusetts 02454-9046 (781) 622-1000 ---------------------- Approximate date of commencement of proposed sale to public: As soon as practicable after the Registration Statement has become effective. If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. [X] If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act of 1933, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. [ ] If this form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act of 1933, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. [ ] ---------------------- This post-effective amendment removes from registration 18,234 shares of ThermoRetec Corporation's common stock, $.01 par value per share, which remained unsold as of the date of the filing of this post-effective amendment. The registration is hereby terminated. SIGNATURES Pursuant to the requirements of the Securities Act, the Registrant has duly caused this Post-Effective Amendment No. 4 to Registration Statement on Form S-3 (Reg. No. 33-77818) to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Concord, Massachusetts, on this 12th day of November, 1998. THERMORETEC CORPORATION By: /s/ Robert W. Dunlap ------------------------- Robert W. Dunlap President and Chief Executive Officer Signature Title Date - --------- ----- ---- President, Chief November 12, 1998 /s/ Robert W. Dunlap Executive Officer and - ------------------------- Director (Principal Robert W. Dunlap Executive Officer) /s/ John N. Hatsopoulos* Chief Financial Officer November 12, 1998 - ------------------------- and Senior Vice President John N. Hatsopoulos (Principal Financial Officer) /s/ Paul F. Kelleher* Chief Accounting Officer November 12, 1998 - ------------------------- (Principal Accounting Paul F. Kelleher Officer) /s/ John P. Appleton* Chairman of the Board of November 12, 1998 - ------------------------- Directors John P. Appleton Director November __, 1998 - ------------------------ Elias P. Gyftopoulos /s/ Fred Holubow* Director November 12, 1998 - ------------------------ Fred Holubow /s/ Theo Melas-Kyriazi* Director November 12, 1998 - ------------------------ Theo Melas-Kyriazi /s/ Frank E. Morris* Director November 12, 1998 - ------------------------ Frank E. Morris /s/ William A. Rainville* Director November 12, 1998 - ------------------------ William A. Rainville *By: /s/ Seth H. Hoogasian ------------------------ Seth H. Hoogasian Attorney-in-Fact