Exposure to certain chemicals commonly used in elementary schools as cleaners or pesticides causes allergic reactions in some children  Elementary school nurses in Renston report that the proportion of schoolchildren sent to them for treatment of allergic reactions to those chemicals has increased significantly over the past ten years
Ttherefore, either Renston' s schoolchildren have been exposed to greater quantities of the chemicals, or they are more sensitive to them than schoolchildren were ten years ago
Children who are allergic to the chemicals are no more likely than other children to have allergies to other substances.