Polyoxyethylene Nonylphenol (NP-9) is a surfactant. NP-9, or nonylphenol ethoxylate, is used primarily, as the name suggests, as a nonionic (having no electric charge in water) surfactant. A surfactant, by the way, is a substance that lowers the surface tension between two liquids or a liquid and a solid, giving nonylphenol ethoxylate the ability to disperse one form of matter into another. NP-9 is a man-made substance created for industrial and domestic chemical or detergent preparations. This waxy or oily solid may be colorless or carry a slight amber/orange tint. Color may darken over time and this is normal and will not affect performance.