The forthcoming UK Control of Major Accident Hazards (COMAH) regulations under the European Community's Seveso II Directive will impose a new formal requirement to test emergency plans. This might be approached as an added burden on industry to demonstrate safe operation, or can be viewed alternatively as an opportunity to improve crisis management systems and thereby decrease the risks to the business. Crisis is by nature an ambiguous and complex environment, demanding endless initiative, inventiveness, communication, co-ordination and learning. Because large-scale crises threatening the entire business are not frequent, learning from experience must be replaced by competence-assurance based on systems thinking, on risk assessment, on wide scenario simulations and on rigorous training. This paper discusses the benefits from various types of testing of emergency plans and from a business approach to continuous improvement in crisis management capability.