http://www.suntimes.com/news/metro/264504,CST-NWS-dog20.article

Two dogs died in Grant Park (Chicago) when they stepped on a live manhole. One of the dogs bit the owner when she tried to save it. Park district electricians say it would be an unlikely hazard for humans. I would agree that this would be less hazardous to humans, but only in the present tense, as it happened in February! In the summer there are hundreds of people in this park on any given day. Surely some of them rug rats are running around barefoot.