The Chemical and Biological Incident Risk Assessment and Management model is an example of a structured system that can be applied to all chemical and biological incidents. The model provides a standard approach that incorporates the basic elements of a hazard and risk assessment. The model involves five steps. Step 1: the idea of recognition (asking the right questions). Upon arrival at the scene, personnel must be able to identify the exact nature of the event and potential safety and/or health hazards as quickly as possible prior to entering potentially contaminated areas. This includes an assessment of hazards present, the relative risks, and the measures that can be implemented to safely manage or eliminate them. Step 2: evaluation (obtaining accurate information). After initial hazard information is collected during the recognition phase, personnel must attempt to corroborate the information to adequately evaluate the potential impact to personnel and to identify the necessary safety precautions. This can best be accomplished by a thorough interviewing process with appropriate sources of information such as witnesses, building owners/occupants, and any other persons on the scene. Step 3: implementation (doing the right thing). Once the recognition and evaluation process is completed, and a site safety plan has been prepared, personnel are ready to implement an operational plan and to enter the scene to initiate their preliminary investigation within the framework of the Incident Management System. Step 4: verification (measuring progress). During this implementation phase of the operation plan, personnel need to constantly verify and evaluate progress to determine if any changes may be warranted or their activities need to be terminated for safety reasons. Step 5: documentation (sharing information). Documentation is the process of recording the results of the hazard and risk assessment process and should include: chemical and biological agents involved, resources, contributing factors, documentation of injuries or fatalities, personal protective clothing, briefing, and incident action plan. And finally the key to effectively responding to a chemical or biological incident includes the following: a written Safety and Health Program, personnel training, a drill and exercise program, and equipment use, storage and maintenance.