The National Aeronautics and Space Administration (NASA) developed an Environmental Management System (EMS) based on the ISO 14001 standard. The EMS procedures were developed to provide maximum flexibility to the individual NASA Centers while meeting the requirements of ISO 14001 and Executive Order 13148. The EMS was tested at Glenn Research Center in Cleveland, Ohio, Johnson Space Center in Houston, Texas, and Stennis Space Center in Bay St. Louis, Mississippi. The pilot study was undertaken to better understand implementation challenges, costs, resource requirements, and benefits. Implementation costs are presented by site population and implementation phases. Potential benefits included increased involvement of management and shop level personnel; reduced mission delays; improved procedures; reduction in single point failures; identification of pollution prevention opportunities; improved compliance; and better relationships with regulators and the public. © 2002 Wiley Periodicals, Inc.