A.M. Viens, Queen Mary University London introduces to the notion of normative uncertainty and illustrates the ethics of risk regulation in emergency. He does not only offer an inspiring overview on how normative uncertainty and ethics can influence and shape emergency risk regulation, but also illustrates how regulatory systems and their responses to emergency will have to recognize and accommodate the problem of normative uncertainty in order to maximize the potential for deliberative and co-operative action in emergencies. 1st HEC workshop on regulation. Emergency regulation under the thread of a catastrophe: a hard look at the volcanic ash crisis. A conference organised by Alberto Alemanno, HEC Paris. 10 & 11 november 2010. More info at http://www.albertoalemanno.eu