EXHIBIT 23.1 CONSENT OF INDEPENDENT ACCOUNTANTS We hereby consent to the incorporation by reference in the Registration Statement on Form S-8 (No. 33-37279) of Hercules Incorporated of our report dated June 17, 2003 relating to the financial statements of the Hercules Incorporated Savings and Investment Plan, which appears in this Form 11-K. /s/ Cogen Sklar LLP - -------------------------- Bala Cynwyd, Pennsylvania June 30, 2003 15