Nonyl Phenoxy Ethoxylate also known as NPE is a synthetic (petroleum-derived) nonionic surfactant (cleaning agent) that is used in cleaning products such as liquid laundry detergents and hard surface spray and dilutable cleaners. NPE can mimic the hormone estrogen. Exposure to NPE has resulted in hermaphroditic fish presenting both male and female sexual organs in certain laboratory studies. There is also some experimental evidence indicating that NPE reduces sperm counts in rats.