Chris Kurtz, manager of substations for KCP&L, said the stations' electricity levels are such that just being near anything conducting power could endanger the thieves. Utility repair crews are also at risk, in part because they are working on substations where the damage is not necessarily fully known.
An outage, injury or death is inevitable if the thefts continue, he said, and they have been increasing.
"It's only a matter of time before one of these occurs," he said.
Ken Geremia, a spokesman for the Copper Development Association, said there always had been a few thefts of copper, which is 100 percent recyclable. But when its price rises, copper draws more attention, causing something like what is happening now in Kansas City.
"Thieves are often not smart, and this proves it," he said.