The term "weapons of mass destruction," or WMD, refers to four principal classes of weapons that can have a significant impact on our environment and, more importantly, on the health of the people living there-large explosive devices, chemical agents, biological agents, and nuclear or radiation-producing weapons. Until now, public policy has concentrated on detecting and reducing the threat from these weapons and preventing their release. In the wake of the events of September 11, 2001, more attention in the health care sector is being focused on responding to their release. To be successful, the health care response to the release of a weapon of mass destruction must have several important characteristics. Simply stated, but far more difficult to accomplish, they are:
1. Protection of those who are not initially exposed from eventually becoming affected;
2. Identification of those who have been exposed so that appropriate steps can be taken to prevent their exposure from progressing to clinical illness; and
3. Assurance that those who are symptomatic have timely access to appropriate health care.
In the paper, the variety of effects that each type of weapon of mass destruction may produce is explored. After determining when, how, and where a weapon has been released, the first challenge for the public health sector is to identify the affected population, to communicate the risk analysis to the public, and then to take the steps required to enhance their protection. To illustrate the variety of consequences that may affect those exposed, several examples are provided from events that have occurred over the last three decades. Lessons are drawn from these examples, including some that may assist in determining which populations are most likely to be affected.