The chemical accident risk assessment thesaurus: a tool for analyzing and comparing diverse risk assessment processes and definitions.

The Chemical Accident Risk Assessment Thesaurus (CARAT) is a database of the laws, regulations, guidance documents, and definitions of terms related to the risk assessment of accidental releases of chemicals from fixed installations. The database also contains information on the application of risk assessment methodologies to specific examples of potential chemical releases. The Organization for Economic Cooperation and Development urged the development of the Thesaurus to improve the communication among the member countries about the risk assessment of hazardous installations. The difficulty of communication is based in large part on the fact that certain "terms of art" have different meanings in different countries and cultures, or that different terms of art are used to address the same concept. The CARAT is designed to circumvent these difficulties, and is especially useful as a tool to analyze the definitions of terms related to risk assessment. Entries into the CARAT contain information from various international, national, and regional agencies that relate to risk assessment processes and definitions focused on accidental chemical releases. The entire system is accessible via the Internet. Retrieval of information from the CARAT is facilitated by five different searching tools: two of them are designed to search the CARAT for its entries. One facility is designed to search for laws and regulations, specific risk assessment cases (SRA), and risk assessment guidance documents (RAG) related to chemical accidents. The second search facility deals with entries of definitions. The design of the CARAT is ideally suited to capture the sense of definitions that are expressed as either a procedural definition (an "operation on a concept") or a conceptual definitions (just the "concept"). A powerful third query tool is the "Comparison" facility. This query tool allows the user to compare the details CARAT entries of laws and regulations, SRA, RAG, or definitions, in any combination. The remaining two tools can perform searches by identifying entries that contain either certain combinations of hierarchical or descriptor details. Both types can be conducted in Boolean "and/or" mode.