Exercise on WHO Human Health Risk Assessment Toolkit (HHRA Toolkit) Working Group: Case study on Accidental release of Chlorine Gas Objective The objective of this case study is to demonstrate how the principles and roadmaps that comprise the Toolkit can be used by a public health or related professional in the immediate response to an acute chemical incident that involves the general public. Numerous accidents of this type have occurred around the world, some of which are profiled in the WHO Manual for the Public Health Management of Chemical Incidents. Such incidents are typically accidental and although infrequent may result in substantial chemical exposures that pose significant risks to large groups of people. An important function immediately after the incident is to identify those actions that achieve the best outcome for the health of the public and the status of the environment. The scenario described in this case study reflects the early stages of the response phase of a chemical incident when officials strive to achieve the best outcome. The incident is the accidental release of chlorine. Statement of the Problem During the early hours of July 15 in a large city in northern Africa (in this fictional case study we use Algiers, Algeria as an example) employees at a refrigerant coolant processing facility noted chlorine gas leaking into the refrigerant coolant system. After 20 minutes of investigating the leak, plant officials alerted the public health authorities to the accident and noted concerns about communities surrounding the plant. Plant officials estimated that workers would need up to 1 hour to seal the leak and that up to 1,800 kilograms of chlorine gas were likely to be released to the air from ground level. At the time of the release, winds were from the north at approximately 5 meters per second, the sky was clear, and the temperature was 22 C.
Exercise on WHO Human Health Risk Assessment Toolkit (HHRA Toolkit) Working Group: Case study on Accidental release of Chlorine Gas Objective The objective of this case study is to demonstrate how the principles and roadmaps that comprise the Toolkit can be used by a public health or related professional in the immediate response to an acute chemical incident that involves the general public. Numerous accidents of this type have occurred around the world, some of which are profiled in the WHO Manual for the Public Health Management of Chemical Incidents. Such incidents are typically accidental and although infrequent may result in substantial chemical exposures that pose significant risks to large groups of people. An important function immediately after the incident is to identify those actions that achieve the best outcome for the health of the public and the status of the environment. The scenario described in this case study reflects the early stages of the response phase of a chemical incident when officials strive to achieve the best outcome. The incident is the accidental release of chlorine. Statement of the Problem During the early hours of July 15 in a large city in northern Africa (in this fictional case study we use Algiers, Algeria as an example) employees at a refrigerant coolant processing facility noted chlorine gas leaking into the refrigerant coolant system. After 20 minutes of investigating the leak, plant officials alerted the public health authorities to the accident and noted concerns about communities surrounding the plant. Plant officials estimated that workers would need up to 1 hour to seal the leak and that up to 1,800 kilograms of chlorine gas were likely to be released to the air from ground level. At the time of the release, winds were from the north at approximately 5 meters per second, the sky was clear, and the temperature was 22 C. Your group forms part of the local public health authorities to assess the health risks and to provide recommendations concerning evacuation. Exercise tasks: Working in groups - Session 1: - Discuss the health issues of concern in this case study. Formulate the health problem you would like to address with your human health risk assessment. - Follow the roadmaps in the Toolkit for (a) hazard identification; and (b) hazard characterization and guidance/guideline value identification and address the questions mentioned there. ⇒ Briefly, report your findings to plenary. Working in groups - Session 2: - Follow the roadmap in the Toolkit for exposure assessment and address the questions mentioned there. - Discuss from where you can get exposure information that is needed for your risk assessment and develop an exposure assessment strategy. ⇒ Briefly, report your findings to plenary. - Assess exposure with the information at hand. Working in groups - Session 3: - Characterize the risks and discuss your findings. - Briefly discuss what you would do to address the health risks you have assessed and at what time scale (e.g. evacuation, shelter-in-place, others). ⇒ Final report to plenary. (Please consider a scenario where your group is briefing the Health Minister on the outcome of the risk assessment) . Assessment Toolkit (HHRA Toolkit) Working Group: Case study on Accidental release of Chlorine Gas Objective The objective of this case study is to demonstrate how the principles and roadmaps. issues of concern in this case study. Formulate the health problem you would like to address with your human health risk assessment. - Follow the roadmaps in the Toolkit for (a) hazard identification;. is the accidental release of chlorine. Statement of the Problem During the early hours of July 15 in a large city in northern Africa (in this fictional case study we use Algiers, Algeria