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                                                                    EXHIBIT 31.1

              CERTIFICATION OF PERIODIC REPORT UNDER SECTION 302 OF
                         THE SARBANES-OXLEY ACT OF 2002

I, Paul J. Norris, certify that:

    1.   I have reviewed this annual report on Amended Form 10-K of W. R. Grace
         & Co.;

    2.   Based on my knowledge, this 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
         such statements were made, not misleading with respect to the period
         covered by this report;

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

    4.   The registrant's other certifying officers and I are responsible for
         establishing and maintaining disclosure controls and procedures (as
         defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the
         registrant and have:

              (a)  designed such disclosure controls and procedures, or caused
                   such disclosure controls and procedures to be designed under
                   our supervision, to ensure that material information relating
                   to the registrant, including its consolidated subsidiaries,
                   is made known to us by others within those entities,
                   particularly during the period in which this report is being
                   prepared;

              (b)  evaluated the effectiveness of the registrant's disclosure
                   controls and procedures and presented in this report our
                   conclusions about the effectiveness of the disclosure
                   controls and procedures, as of the end of the period covered
                   by this report based on such evaluation; and

              (c)  disclosed in this report any change in the registrant's
                   internal control over financial reporting that occurred
                   during the registrant's most recent fiscal quarter (the
                   registrant's fourth fiscal quarter in the case of an annual
                   report) that has materially affected, or is reasonably likely
                   to materially affect, the registrant's internal control over
                   financial reporting; and

    5.   The registrant's other certifying officers and I have disclosed, based
         on our most recent evaluation of internal control over financial
         reporting, to the registrant's auditors and the audit committee of the
         registrant's board of directors (or persons performing the equivalent
         functions):

              (a)  all significant deficiencies and material weaknesses in the
                   design or operation of internal control over financial
                   reporting which are reasonably likely to adversely affect the
                   registrant's ability to record, process, summarize and report
                   financial information; and

              (b)  any fraud, whether or not material, that involves management
                   or other employees who have a significant role in the
                   registrant's internal control over financial reporting.


         Date:  August 9, 2004
                                                       /s/ Paul J. Norris
                                                       -----------------------
                                                       Paul J. Norris
                                                       Chairman and
                                                       Chief Executive Officer