The discovery, development, and application of sustainable chemical reactions that create no waste or generate only benign wastes. The idea that toxic chemicals, once created, can be contained or prevented from entering the environment is unrealistic. Since some portion of the toxins will always enter the environment, whether through use, processing, disposal, or unforeseen circumstances such as accidents, terrorism, or natural disasters, green chemistry solutions are applied at the molecular level to avoid creating toxins in the first place. Using green chemistry to prevent pollution provides a more efficient approach to preserving human health and the environment than waste processing or remediation.