E.I. du Pont de Nemours & Company is a chemical company commonly known as the DuPont Company. DuPont introduced its first reverse osmosis permeators for water desalination in 1969 under the trade name "Permasep" as a result of its contusion research in polymer chemistry and synthetic fibers. DuPont designed two types of permeator membranes: hollow-fiber and spiral-wound.

DuPont made the hollow-fiber B-9, the first Permasep permeator commercially available, in 1969. Following the introduction of the B-9, DuPont continued to unveil new and refined permeator models. For its innovation in developing the Permasep B-9 permeator, the company was awarded chemical engineering's Kirkpatrick Chemical Engineering Achievement Award in 1971. DuPont introduced the B-10 permeator, the first permeator to make seawater desalination commercially feasible, in 1974. In 1989, DuPont Permasep patented a chloramines process that created reliable biological control of surface seawater plants and prevented the formation of trihalomethanes created when water is treated with chlorine. In 1991, DuPont sold the spiral-wound permeator section of their business to TriSep. The sale of the spiral-wound permeators left DuPont to focus on developing more efficient hollow-fiber permeators. In 1992, DuPont introduced the B-10 Twin permeator. The Twin drastically reduced operating costs and was more efficient than the standard B-10. Permasep, originally part of the DuPont Company's polymer sector, was switched to the fibers sector in 1993, where it joined fibers like Kevlar and Nomex.

By 1997, DuPont had sold over 1.5 billion gallons of desalting capacity. DuPont had Permasep sales offices in seven countries: United States, Japan, United Kingdom, Switzerland, Saudi Arabia, Germany, and Belgium. These offices sold Permasep products across the globe, especially to the Middle East. Customers there included Jordan, Kuwait, Libya, United Arab Emirates, Iraq, Iran, Saudi Arabia, and Bahrain, which had the world's largest reverse osmosis plant. Other countries include Malta, the Canary Islands, Italy, Venezuela, Chile, Morocco, and Singapore. Despite Permasep's success, DuPont decided to discontinue the production of hollow-fiber permeators in 1997. The reverse osmosis market slowly shifted away from hollow-fiber permeators toward spiral-wound permeators. This shift was the deciding factor in the decision to discontinue production.