Microbiologists from the University of Essex, UK have used microbes to break down and remove toxic compounds from crude oil and tar sands. These acidic compounds persist in the environment, taking up to 10 years to break down. Mr Richard Johnson, presenting his research to the Society for General Microbiology's meeting at Heriot-Watt University, Edinburgh, described how, by using mixed consortia of bacteria, they have achieved complete degradation of specific compounds in only a few days.