Toluene is a toxic substance used in petrol, paint, paint thinners and adhesives. Through spills and improper disposal, toluene can contaminate soil and ground water environments. Using microorganisms to clean up toluene-contaminated sites can be an effective and economical way of degrading the pollution before it can spread throughout the environment. There is concern, however, that these non-native microorganisms may upset the balance of the ecosystem through unnatural competition or horizontal synthetic gene transfer. We are engineering the Toluene Terminator as a way to neutralize toluene pollution while addressing these concerns. It will have the capabilities of sensing and mineralizing the toluene into carbon dioxide and water, but this terminator will not be back. The Toluene Terminator will have a suicide mechanism which kills the bacteria in the absence of toluene.