Soapless detergent is a synthetic cleaning agent distilled from petroleum-based (petrochemical) and/or oil and fat-based (oleochemical) substances. Unlike soap-based cleansers, the chemical composition of soapless detergent prevents the formation of soap scum when combined with hard water. Soapless detergents may be found in industrial cleansers, household cleansers and even personal care products.
Soapless detergent was first developed during World War I in response to both a need for a cleanser that performed better in hard water and a shortage of the vegetable and animal-sourced fats and oils used to make soap-based cleansers.
Soapless detergent is not considered as friendly to the environment as soap-based cleanser because it takes longer to break down and be re-absorbed once it is washed away.This increases the time during which it may be ingested by fish or other wildlife.
Much of the negative attention given to soapless detergents is focused on the presence of phosphorus in the form of phosphates. While phosphates are a plant nutrient, excessive levels of phosphates in a body of water can increase algae growth and create an imbalance in the ecosystem. For this reason, the presence of phosphates in certain types of soapless detergent (such as laundry detergent) is regulated in many countries, including the United States.