Nonaccidental releases of chemicals into the environment occur ubiquitously as a result of manufacturing activities and consumer use and disposal practices. The potential impact of such releases depends on the inherent chemical properties, the quantities that are discharged, and the manner in which these are partitioned in the receiving environment. The science of environmental risk assessment refers to a set of approaches and methodologies designed to guide the systematic evaluation of the potential risks associated with a specific environmental exposure. It is a relatively young scientific discipline that has grown with leaps and bounds in the past 2 decades. The environmental risk assessment of consumer products such as laundry detergents, disposed of down the drain, represented one of its earliest applications. Recognition of the importance of accurate assessment of the environmental fate and effects of consumer products helped encourage the development of test methods, tools, and approaches. Every responsible consumer product manufacturer today considers environmental risk assessment an integral component of product development.