EXHIBIT 10-D

                                                May 12, 2000

Mr. Robert C. Flexon
4000 Pacific Avenue, #303
Marina del Rey, CA  90292

Dear Bob:

      I am pleased to confirm the terms and conditions of your offer to join
Hercules Incorporated in the position of Vice President, Business Analysis
within the Finance Division of Hercules. This position will report to George
MacKenzie, Executive Vice President and Chief Financial Officer.

      Our offer includes the following components:

      1.    Annual Base Salary: $240,000 payable in 12 equal monthly
            installments. Pursuant to our salary administration policy, salary
            reviews are conducted each March 1st.

      2.    2000 MICP Target Opportunity: Your target annual incentive
            opportunity under the Hercules Management Incentive Compensation
            Plan (MICP) is 50% of your base salary and will be prorated for the
            number of months from your start date to the end of the year. The
            maximum payout is 200% and, of course, the minimum is zero. Any
            payouts above the target amount are made in discounted restricted
            stock.

      3.    Long-Term Incentive: In this position, you are eligible to receive
            annual grants under the Hercules Long-Term Incentive Compensation
            Plan (LTICP). The 2000 award was for 35,500 non-qualified stock
            options. Upon commencing employment, you will receive a pro-rated
            number of options based on the number of months from your start date
            to the end of the year with the exercise priced determined on the
            first day of the month following your start date.

      4.    Benefits: Your benefits will be covered under the current Hercules
            Incorporated plan per the enclosed Benefits overview.

      5.    Deferred Compensation: In the fall of 2000, you become eligible to
            participate in the Hercules Deferred Compensation Plan. This plan
            provides the option to defer before-tax salary and/or target MICP
            amounts. More information will be provided to you on this plan when
            you become eligible to participate.


Robert C. Flexon
May 12, 2000
2


      6.    Executive Stock Purchase Program: In the fall of 2000, you will
            become eligible to participate in the Executive Stock Purchase
            Program. This program, under the LTICP, provides you with the option
            of converting salary, target MICP amounts, and Nonqualified Pension
            benefits into Hercules Restricted Stock at a 15% discount. The
            program also provides for the exchange of Nonqualified Savings Plan
            balances for restricted stock with no discount. More information
            will be provided to you on this program through the Corporate Human
            Resources Department.

      7.    Relocation: You will be eligible for the Hercules relocation policy
            applicable to homeowners if you complete a move of your principal
            residence to the Wilmington area anytime within the next year.

      8.    Financial Planning: You will be reimbursed for Financial / Tax
            planning or Tax preparation up to $5,000 annually. Our preferred
            providers are PricewaterhouseCoopers and AYCO, however, you may
            select a vendor of your choice. Please contact Richard Fluri, vice
            president, Human Resources, for program details.

      9.    Signing Bonus: You will receive as part of your offer an award of
            10,000 non-qualified stock options with an exercise price determined
            on the first day of the month following your start date.

      In the event that your position is eliminated, you will be eligible to
receive one year of severance. Should an enhanced severance program be offered
in the future, this severance benefit is not additive, but rather the program
that is most favorable will prevail. This benefit is triggered by Hercules and
will not be paid in the event that you resign.

      You are also eligible for a special severance of two years in the event of
a Change of Control at Hercules Incorporated. Program details will be provided
upon employment.

      This offer is contingent upon two issues. You must successfully pass our
standard pre-placement physical examination before your anticipated starting
date. A part of this examination will be a test to detect the use of drugs or
alcohol. If you are currently using prescription drugs, please bring your
prescription with you to the physical. In addition, we must verify employment
eligibility under the Immigration Reform and Control Act.

      Bob, I am excited about having you as part of the Hercules team in this
critical role. I look forward to working with you to make this a personally and
professionally rewarding opportunity.



Robert C. Flexon
May 12, 2000
3


      To indicate your review and acceptance with the above terms please sign a
copy of this letter and return it to me within three days.

                                                    Best regards,


                                                    June B. Barry
                                                    Executive Vice President,
                                                    Corporate Resources Group

Accepted by:


- -----------------------
Robert C. Flexon

Enclosure