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                                                                    EXHIBIT 31.1

                CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350,
                       AS ADOPTED PURSUANT TO SECTION 302
                       OF THE SARBANES--OXLEY ACT OF 2002

I, A. John Leach, Jr., certify that;

     1)   I have reviewed this annual report on Form 10-K of Covista;

     2)   Based on my knowledge, this annual report does not contain any untrue
          statement of a material fact or omit to state a material fact
          necessary to make the statements made, in light of the circumstances
          under which statements were made, not misleading with respect to the
          period covered by this annual report.

     3)   Based on my knowledge, the financial statements, and other financial
          information included in this annual report, fairly present in all
          material respects the financial condition, results of operations and
          cash flows of Covista as of, and for, the periods presented in this
          annual report.

     4)   Covista's other certifying officers and I are responsible for
          establishing and maintaining disclosure controls and procedures (as
          defined in Exchange Act Rules 13a-14 and 15d-14) for Covista and have;

               a)   Designed such disclosure controls and procedures to ensure
                    that material information relating to Covista, including its
                    consolidated subsidiaries, is made known to us by others
                    within those entities, particularly during the period in
                    which this annual report is being prepared;

               b)   Evaluated the effectiveness Covista's disclosure controls
                    and procedures as of a date within 90 days prior to the
                    filing date of this annual report (the "Evaluation Date");
                    and

               c)   Presented in this annual report our conclusions about the
                    effectiveness of the disclosure controls and procedures
                    based on our evaluation as of the Evaluation Date;

     5)   Covista's other certifying officers and I have disclosed, based on our
          most recent evaluation, to Covista's auditors and the audit committee
          of Covista's Board of Directors (or persons performing the equivalent
          functions);

               a)   All significant deficiencies in the design or operation of
                    internal controls which could adversely affect Covista's
                    ability to record, process, summarize, and report financial
                    data, and I have identified for Covista's auditors any
                    material weaknesses in internal controls; and

               b)   Any fraud, whether or not material, that involves management
                    or other employees who have a significant role in Covista's
                    internal controls; and

     6)   Covista's other certifying officers and I have indicated in this
          annual report whether there were significant changes in internal
          controls or in other factors that could significantly affect internal
          controls subsequent to the date of our most recent evaluation,
          including any corrective actions with regard to significant
          deficiencies and material weaknesses.


Date: April 29, 2005                   By: /s/ A. John Leach, Jr.
                                           -------------------------------------
                                           A. John Leach, Jr.
                                           President and Chief Executive Officer


                                  EXHIBIT 31.1