Every year,numerous environmental disasters and emergencies occur across the globe with far-reaching impacts on human health and the environment.The ability to rapidly assess an environmental emergency to mitigate potential risks and impacts is paramount.However,col-lating the necessary evidence in the early stages of an emergency to conduct a robust risk assessment is a major challenge.This article presents a methodology developed to help assess the risks and impacts during the early stages of such incidents,primarily to support the European Union Civil Protection Mechanism but also the wider global community in the response to environmental emergencies.An online rapid risk and impact assessment tool has also been developed to promote enhanced collaboration between experts who are working remotely,considering the impact of a disaster on the environment and public health in the short,medium,and long terms.The methodology developed can support the appropriate selection of experts and assets to be deployed to affected regions to ensure that potential public health and environ-mental risks and impacts are mitigated whenever possible.This methodology will aid defensible decision making,communication,planning,and risk management,and pre-sents a harmonized understanding of the associated impacts of an environmental emergency.