At a regional level, the European States, assisted by the UN Economic Commssion for Europe have adopted in 1992 in "Helsinki" a Convention on the Transboundary Effects of Industrial accident, which is the most developed international instrument concerning assistance in environmental emergencies. It obligates the states under the jurisdiction of which an industrial accident occurs or is capable of occurring to ensure, for hazardous activities, the preparation and implementation of on-site contingency plans, including suitable measures for response and other measures to prevent and minimize transboundary effects.