Philadelphia ? The growing popularity of hybrid vehicles is a step toward cleaner air and less dependance on gasoline. But for rescuers at accident scenes, they represent a potential new danger: a network of high-voltage circuitry that may require some precise cutting to save a trapped victim.

“You don’t want to go crushing anything with hydraulic tools,” said Samuel Caroluzzi, an assistant chief with the Norristown Fire Department outside Philadelphia. “It’s enough to kill you, from what they’re telling us in training.”

Hybrids draw power from two sources, typically a gas or diesel engine combined with an electric motor. The battery powering the electric motor carries as much as 500 volts, more than 40 times the strength of a standard battery.

Manufacturers have put in place a laundry list of safety checks that the car’s computer must go through for the electrical system to run. They’ve published guides showing where the electric components are on their models; on the Toyota Prius and other hybrids, the high-power cables are colored bright orange to catch the eye of a rescue worker or a mechanic.

But there are concerns over what happens if something goes wrong and the battery, ignition and other points are inaccessible.

“It’s the ‘what-if’ that worries me,” said David Castiaux, an instructor for Mid-Del Technology Center in Del City, Okla., who teaches rescue workers about hybrids.

Chris Peterson, a service training instructor for Toyota, said the Prius’ electric system should shut down if anything goes wrong. “There should not be high voltage in those cables, but I’m not going to stand up and say there isn’t,” he said.