The EPA uses information technologies to help achieve its main goals: the implementation of policies protecting the environment and the enforcement of compliance with its regulations. Geographic information systems, with the capacity to digitally map large areas and combine spatial information with data, are among the computer software products most valuable to the agency. The EPA spends almost one quarter billion dollars on information systems each year. Officials estimate that the process of cleaning up US air and water will call for $24 billion in annual expenditures by business and government. Voluntary efforts of polluting companies to clean up their operations and devise ecologically sound methods of operation are crucial to this endeavor.