Provides direction to regulators and practitioners on integrating EA into remedial decision making for a smooth transition between aggressive remediation and monitored natural attenuation. The CD also contains the Enhanced Attenuation of Chlorinated Organics: Electronic Resource Guide.

Review of regulatory issues associated with PRBs.

Description of practices to be used to recognize and evaluate the presence of natural attenuation of chlorinated solvent contamination.

Presents a summary of results of surveys returned by people who took the natural attenuation course.

Evaluation of state practices for establishing and implementing closure criteria for bioventing, vapor extraction, and natural attenuation of petroleum hydrocarbons and chlorinated solvents.