Exposure to toxic substances in the environment is an ever more common event, that may cause physical as well as psychological harm. When an entire community is exposed, the term 'toxicological disaster' is used. The mere threat of such an event may be a source of stress, associated with changes in mental health, physical health, and changes in health-related behaviors. A review is presented of the literature about the effects of the stressful experience of toxicological disasters on health and health-related behaviors. Three questions are examined: (a) do toxicological disasters represent a specific type of stressor, different from other stressors?; (b) which stress-mediated health effects have been observed in the aftermath of toxicological disasters? and (c) is there evidence for a higher vulnerability in certain identifiable risk groups? On the basis of the available literature, it is concluded that toxicological disasters may have profound effects on subjective health, especially on symptom reporting, and on a number of psychophysiological parameters. Evidence for a substantial impact of disaster-related stress on either physical or psychiatric morbidity remains inconclusive. In this respect toxicological disasters do not appear to differ from other stressors. There is some evidence that toxicological disasters may have a more pronounced effect on health-related behaviors, especially on reproductive behavior (number of births and abortions). Women, and especially those who have young children to care for, appear to be more at risk for the observed health effects. The evidence for a higher vulnerability in other risk groups (e.g., former psychiatric patients remains inconclusive.