Toxicity risk assessments were developed by DW years ago to locate substructures within chemical structures divided in four classes (Mutagenesis, Tumorigenicity, Reproductive Interference, Irritant). These risks are alerts, not reliable toxicity predictions, nor 100 % free of any toxic effects. To assess toxicity prediction's reliability, DW ran a set of known toxic compounds and compare them to known non-toxic compounds to evaluate whether they have high, medium or low risk of being toxic. Structural fragment analysis generated toxicity alerts based on the Registry of Toxic Effects of Chemical Substances (RTECS data base) () and on > 3000 traded drugs non-toxic compounds ().