ATMI (ATMI) 10-Q 2004 Q2 Quarterly report

Exhibit 32

CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

     In connection with the Quarterly Report on Form 10-Q of ATMI, Inc. (the “Company”) for the period ending June 30, 2004 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), as Chief Executive Officer of the Company and Chief Financial Officer of the Company, each hereby certifies, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that:

     (1) The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

     (2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ Eugene G. Banucci

Name: Eugene G. Banucci, Ph.D.

Title: Chief Executive Officer

Date: August 5, 2004

/s/ Daniel P. Sharkey

Name: Daniel P. Sharkey

Title: Chief Financial Officer

Date: August 5, 2004

A signed original of this written statement required by section 906 of the Sarbanes-Oxley Act of 2002 has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.

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