One of the most challenging problems facing the fire service today is the combined fire and hazardous/toxic chemical incident. Decisions have to be made regarding the timing of fire fighting activities with respect to evacuation priorities. In many cases, a decision must be made as to whether or not to fight the fire at all. Where the chemicals or products involved are water reactive, fighting the fire may make matters worse, endangering the firefighters or the general population. Just such a situation presented itself to Chief Raymond Sullivan of the Springfield, Massachusetts Fire Department and the city's hazardous materials incident response team on Friday, June 17, 1988. The incident occurred in that part of an 87-year-old industrial building housing a company that produced water treatment chemicals for swimming pools. Rain leakage wetted chemicals that released chlorine along with sufficient heat to cause ignition of ordinary combustibles. In the course of the incident, large amounts of chlorine gas were released, triggering several levels of evacuation involving more than 6,000 people.