This paper examines whether there is an externality of parental occupational exposure to pesticides on children's health, and whether some children are more severely affected by the externality than others. Using the Hispanic Health and Nutrition Examination survey, we find children of exposed parents are more likely to develop chronic conditions and less likely to attain good health than children of unexposed parents, after controlling for a large set of child and family characteristics. Furthermore, children from low socioeconomic status are most vulnerable to health shocks resulting from pesticides and other related environmental toxins. Our analysis suggests that terminating the pathway of parental occupational exposure would be cost effective to correct the externality. Taken together with earlier findings that poor childhood health is associated with lower adult earnings, our results suggest more attention to be paid to the health shocks from environmental toxins for the poor as a potential mechanism through which the increasing poverty across generations at the very poor takes place: poverty makes individuals more susceptible to health shocks at childhood, which is associated with worse poverty for their children.