The worst peacetime disaster in United States Army history occurred on December 12, 1985 in Gander, Newfoundland. A charter airline carrying 248 soldiers home from peacekeeping duties in the Sinai Desert crashed after a refueling stop, killing all on board. After the crash, Army family assistance workers were appointed to help the surviving family members of each dead soldier. While substantial attention has been paid to the impact of sudden disasters on survivors and bereaved relatives, little is known about the health risks to those who perform helper roles. This study aimed to: a) identify the major stress areas for disaster family assistance workers; b) examine the relation between degree of exposure to these stressors and health; and c) locate risk factors, or resistance resources that might modulate any ill effects of exposure. A survey instrument assessed duration and intensity of family-helping activities and psychological well-being, psychiatric symptoms, major illness indicators, and social and personality variables at 6 months after the crash and again at the 1-year point for 131 family assistance officers. Results indicate a dose-response effect between exposure measured at time 1 and well-being, symptoms, and illness at time 2. Analysis of covariance findings also show that social supports (work supervisors, family, and friends) modulate the effects of exposure on symptoms and well-being. Social supports and the personality style of hardiness (or dispositional resilience) interact to modulate the effects of exposure on illness. These results demonstrate: a) a delayed negative impact of helper stress on family assistance workers, and b) a protective function of social supports and personality hardiness. Further research in this area should thus consider the potential influence of social/situational variables and personality dispositions in coping with disaster helper stress.