The Emergency Control Advisory System (ECAS) is a knowledge-based appliance designed to assist in managing an underground coal mine emergency during the initial. stages before the arrival of trained personnel, and throughout the ensuing hours. It is designed to actively guide users through the problem as well as answering specific queries. A training version for rescue personnel uses the same knowledge base, and it is anticipated that the similarity will make the product more useful in the event of an actual call-out. The system has extensive knowledge navigation facilities to allow both detailed Justifications for advice, and to preview the possible consequences of actions. The system is designed to allow connection to mine-site software if the need arises. It is designed to be available both as a simple initial response system within the reach of small mine sites, or a larger more versatile system for use by rescue stations or larger mines.