Prevention and control of a problem as complex as that of hazardous material spills and their ensuing effects on the population and environment can only be approached based on a comprehensive reliable system for spill incident collection and analysis. The groundwork for such a system was established in a previous program, EPA-600/2-78-066 dated April 1978 'Hazardous Material Spills: A Documentation and Analysis of Historical Data'. The present program developed a detailed spill data base and a completely computerized system for producing reports upon request, with the further capability of generating statistics on any or all spill incidents which are encoded in computer storage. Two logically linked data sets were established. The first set is comprised of incident-related data, while the second is comprised of material-related data. The previously developed computer codes were modified due to the large number of incidents acquired, and to accomodate this dual data base system. New coding techniques also minimize the potential of multiple entries and greatly increase the amount of information that can be stored. These charges have made the data system more nearly universal, providing a more accessible means of retrieving information than was possible using previous retrieval methods.