<PAGE>


                                  EXHIBIT 31.2

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

I, Frank J. Pazera, certify that;

     1)   I have reviewed this quarterly report on Form 10-Q of Covista;

     2)   Based on my knowledge, this quarterly 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 quarterly report.

     3)   Based on my knowledge, the financial statements, and other financial
          information included in this quarterly 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
          quarterly 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
               quarterly report is being prepared;

          b)   [omitted pursuant to the guidance of Release No. 33-8283
               (June 5, 2003)]

          c)   Presented in this quarterly 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);

          d)   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

          e)   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
          quarterly 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: June 14, 2004                                 By: /s/ Frank J. Pazera
                                                        -----------------------
                                                        Frank J. Pazera
                                                        Chief Financial Officer