WILMINGTON, Del. — DuPont says it will soon stop contributing to active employees’ pension plans, a move that will affect the retirement of 13,000 U.S. workers, including 2,800 in Delaware.

The News Journal of Wilmington reports the Delaware-based chemicals company announced Thursday that workers will stop receiving pension contributions either in November 2018 or on the creation date of the first independent company spawned through the proposed $130 billion merger with Dow Chemical.

The news affects only employees in the U.S. and Puerto Rico. Current retirees’ pensions will not be affected.

DuPont expects the changes to reduce its long-term employee benefits obligation by about $550 million. DuPont closed the pension plan to new employees in 2007.