The Toxicity/Residue Database is maintained by the U.S. EPA and is a database for the prediction of toxicity of organic and inorganic chemicals to aquatic organisms. This data base was developed by the EPA Duluth office and became operational in 1999. The data base is derived from more than 500 peer-reviewed references and is a collection of their findings on roughly 200 chemicals and 190 species both marine and fresh water. Data regarding organism response endpoints or effects are measured as the concentration of chemical in the tissue of the test organism at the time which effects such as lethality, metabolic depression, or increased respiration occur. More than 3,000 effects may be queried from a small piece of downloaded software to gather survival, growth or reproductive endpoint effect data.