The use of MICROORGANISMS to remediate environments contaminated by hazardous substances is an innovative technology and an area of intense interest. Although biological technology has been used for decades in wastewater treatment, recent examination of the cost-effectiveness of this technology has led to its application to hazardous chemicals at waste sites. Successes obtained by using the natural metabolic capabilities of bacteria and fungi to clean up soil, sediment, and water have encouraged continued interest and research in bioremediation.