Wilmington, DE, May 26, 2006 - - The Paper Technologies and Ventures Group of Hercules Incorporated (NYSE: HPC) and the Specialty Chemicals Division of MeadWestvaco Corporation (NYSE: MWV) announced an agreement to produce and sell rosin- based paper sizing products in the Americas, effective immediately. Terms of the agreement were not disclosed.

The agreement positions Hercules as the sole agent for marketing, sales and service of both companies’ respective portfolios of rosin sizing agents.  MeadWestvaco Specialty Chemicals will continue to manufacture liquid rosin size, rosin-based surface size and drainage/sizing aids at its facilities in Charleston, S.C., and DeRidder, LA, and will assume the manufacture of Hercules’ rosin-based paper sizing products at these facilities.  MeadWestvaco sizing products marketed by Hercules will retain MeadWestvaco’s known and trusted brand names.

“The strengths of both partners are leveraged through this agreement,” said Ben Ward, President, MeadWestvaco Specialty Chemicals Division.  “Our customers will realize the distinctive advantages of MeadWestvaco’s position as an integrated rosin derivatives manufacturer combined with Hercules’ broad product line and comprehensive service network.”

“This strategic agreement enhances our product and service strengths for our customers in the pulp and paper industry,” said Chet Cross, Director, Hercules Paper Technologies, Americas.  “We are pleased to offer our customers a full line of outstanding paper size products and technologies backed by an uncompromised commitment to innovation, performance and service.” 

Customer sales will be transitioned to Hercules over the coming months as the new infrastructure implementation progresses.