Mountain View (location of Google HQ) has playgrounds where it is most likely unsafe to let your kids play. This is across the road from Google offices at Fairchild. https://cumulis.epa.gov/supercpad/SiteProfiles/index.cfm?fus...
VOC contaminated soil at Fairchild, Intersil and Intel sites should be safe except after flooding from exceptionally heavy rain. Presumably there's a plan to shut the playgrounds, but it's America so who knows...