The tragedy took place during a daily routine familiar to millions _ walking the family dog.
Jodie S. Lane, 30, a doctoral student in clinical psychology at Columbia University Teachers College, never returned from exercising her pets last month. She was electrocuted after one of her two dogs stepped on the metal cover of a utility box on a street in Manhattan's East Village, and current surged through her.
After an investigation, Consolidated Edison announced last week it had found the cause: a partially exposed wire inside the box that had been improperly insulated. The wire was wrapped a year earlier with the wrong kind of tape that had worn away, resulting in the box becoming electrically charged.
"We will learn from this tragedy. We have taken this inquiry very seriously," the utility said. "Testing for stray voltages will be an ongoing program."
Con Ed declined to disclose whether anyone had been disciplined.
Civil engineers said the tragedy underscores the vulnerability, particularly during winter, of an extraordinarily complex portion of New York hidden from public view _ the immense tangle of electrical wires, fiber-optic cables, gas and sewer lines, steam pipes, water mains, tunnels and other systems buried beneath sidewalks and streets.
In Manhattan alone, Consolidated Edison maintains 90,000 miles of underground cables. As a result of Lane's death, it has begun to test 250,000 subterranean structures.
The same day Con Edison announced the cause of Lane's electrocution, an electrician hired by the New York Post discovered an electrified manhole cover on the lower East Side of Manhattan. A Con Edison crew summoned to the scene found that the insulation on a wire was corroded, apparently by salt.
D. Joy Faber, a spokeswoman for the utility, said the crew confirmed the voltage at the location and made repairs. She said the utility plans to inspect all its underground structures in the city within a month, weather permitting.
Some of New York's infrastructure dates back more than 100 years. Day-in and day-out, the underground systems are pounded by the vibration of trucks and cars, which can cause wires and pipes to break _ snow, ice and cold often magnify the problems.
On another freezing day several days after Lane was killed, not far away, a 12-inch water pipe from about 1870 broke, flooding basements and forcing residents from 10 buildings to flee. And, on a single day recently, New York repair crews faced the prospect of trying to fix more than 700 hydrants knocked out of commission by the cold.
While less common than its toll on pipes, the bitter weather also can damage electrical components. The runoff from salt used to melt ice on streets and sidewalks can leak into manholes and metal grates, causing short circuits in the equipment below. The result can be explosions in manholes and fires.
Neighborhood residents who tried to aid Lane were helpless as she lay sprawled on the metal plate in the street. Police, fearing additional electrocutions, kept people away until paramedics using a plastic backboard managed to move her. Attempts to revive Lane at the scene failed, and she was pronounced dead at nearby Beth Israel Medical Center. Her dogs _ a Husky mix and a Chow mix, were injured but survived.
An autopsy by the city medical examiner confirmed that Lane was electrocuted.
Since the death on 11th Street near First Avenue on Jan. 16, the city has received calls from a handful of pet owners about live wires, and utility crews have been dispatched quickly.