NBC aired the episode Monday night after Akron-based FirstEnergy Corp. and other utilities asked the network not to show it.
"They said they were going to run it because it was entertainment," FirstEnergy spokesman Mark Durbin said Tuesday. "We think that kind of thing is irresponsible."
NBC issued a statement saying it took the appropriate steps to warn viewers of the potential dangers. Each "Fear Factor" episode includes a disclaimer warning viewers not to try the stunts themselves.
"Additionally, the episode includes a warning that any electrical current can be extremely dangerous and shocks can result in severe injury or death," NBC said.
Contestants on the reality show perform dangerous and often disgusting stunts in competition for a cash prize.
Competitors in Monday night's episode collected flags while navigating a maze of electrified cables in a power substation. Sparks flew as they received shocks from the cables, which were charged with far less electricity than what a power substation would deliver.
Two contestants on the "Fear Factor" Web site said they were left shaking after receiving multiple shocks during the stunt.
"You just felt it everywhere. It's like one of your eyeballs popping out," said a contestant who is identified only as Randy.
The Arlington, Va.-based Electrical Safety Foundation International expressed concern that the episode will make viewers think that contact with electricity is something that can be withstood without serious injury. It noted that electricity can be fatal even at low current levels.
At least 10 other industry groups joined the Electrical Safety Foundation International in its message, including the American Public Power Association and Underwriters Laboratories Inc.
The Canadian Electricity Association also issued a warning that substations contain lethal currents of electricity. It express concern that the show would "convey the message that an electrical shock is nothing more than a harmless annoyance."
At the request of utilities, several NBC affiliates, including WKYC in Cleveland, aired a crawl during Monday's episode warning of the dangers of substations.
FirstEnergy hasn't had a substation injury since July 2000 when an 8-year-old boy was burned over 75 percent of his body when he was shocked by 23,000 volts of electricity, enough to power an entire neighborhood.
He had climbed over an 8-foot fence topped with barbed wire to get into the substation. Neighbors heard a boom and said the shock threw the boy to the ground unconscious.
"It's very dangerous equipment and we do everything possible to put warnings up and barriers around them because the outcome is never very good," said FirstEnergy spokeswoman Ellen Raines.
Last month, a Cleveland viewer sued NBC for $2.5 million, contending a "Fear Factor" episode in which contestants ate rats made him vomit.