Two manhole covers hurtled through the air on Avenue C between E. 2nd and E. 3rd streets two days ago as a result of a fire in a manhole, and Con Edison customers in the area lost their electrical power.
At around 8 PM the primary explosion reverberated throughout the neighborhood like a cannon. Immediately thereafter the two manhole covers which had been shot into the air returned to earth. Orange flames then erupted from the manholes, their tips transforming into billowing black smoke. It is rumored that salt used during the recent Brooklyn blizzard precipitated the underground electrical explosion. (Brownstoner Brooklyn)
A fire in a Con Ed manhole caused two explosions, a loss of power, and the destruction of a car on January 2nd at Greenwood Avenue and E. 2nd Street.
A car parked near the corner of Vanderbilt and E. Second streets was destroyed when salt-water-drenched underground Con Edison wires ignited, setting off two massive explosions that rattled the usually quiet neighborhood. Gases quickly built up, causing a manhole cover to pop. The underground fire then spread above ground to a nearby vehicle. (New York Post)
Spokesman Bob McGee subsequently confirmed that the manhole fire was the result of salt corrosion on the cables. He explained that several days after it snows, the salt used to treat city streets can corrode the insulation material on underground cables and fires can start. (Brooklyn Daily Eagle)
Today's New York Times reports that
There have been at least 19 such [manhole] fires and explosions since New Year’s Day, according to Consolidated Edison and fire officials.
Salt laid down on wintry streets corrodes cables and makes them more susceptible to catching fire, said a Con Edison spokesman, Chris Olert. A smoldering cable can also release noxious gasses that can build to such intense pressure that the manhole cover pops off. Con Edison has redesigned many of its manhole covers to increase ventilation and to decrease the chance of such a frightening occurrence.
The protective insulation that covers underground electrical cables is subject to a normal amount of degradation over time. Vibrations and nearby construction can add to the degradation by displacing the cables. And salt and melting snow can slip into manholes, eating away at the insulation. The exposed cables can catch fire, causing explosions and a loss or diminishing of electrical power in nearby homes and businesses. In 2004, The New York Times reported that
fire officials say the number of fires in manholes is on the rise, and the ingredients are far from rare.
Melted snow mixes with street salt and washes into a manhole. The slushy mix corrodes the insulation of the underground electrical wires. The insulation slowly burns, releasing flammable gases. Along comes a spark.
Jim Long, a spokesman from the Fire Department, said there might be a larger trend.
On average, about 2,500 total manhole incidents occur each year. Last winter there were 4,600, Mr. Long said.
Manhole incidents can range from simple smoke seepage to explosions that shoot manhole covers several stories into the air, he said.
915 incidents occurred in January alone.
Mr. Long said that there was a deadly risk in the carbon monoxide fumes produced by the fires. Rather than seeping upward, the odorless gas could seep sideways into residences.
The Sanitation Department, Con Edison, and the Utility Workers Union of America pointed fingers at each other about who is to blame:
Kathy Dawkins, a spokeswoman for the Sanitation Department, said that salt usage was up this winter. She said that the city had used more than six times the amount used two winters ago when snowfall was light.
Manny Hellen, president of the Utility Workers Union of America, Local 1-2., said, ''Con Ed keeps fixating on snow and salt because those are the two variables that are outside their control.''
He pointed to aging wires, slackening maintenance policies, cheap materials, and softened inspections as being more important factors to consider.
Katherine L. Boden, chief distribution engineer for Con Ed, said that the utility had tried for years to get the city to switch to a less corrosive de-icer, but the price had been too high.
But Ms. Dawkins said that the city remained open to the idea of using salt alternatives.
''They keep talking about it, but Con Ed has never actually submitted a proposal,'' she said.
Seven years later, cables are still catching fire, and manhole covers are still flying through the air.
If you see smoke or fire coming out of a manhole, call 911 immediately.
If you lose power completely or if you have dim, partial, or flickering lights, report it to Con Edison. Call 1-800-75-CONED (1-800-752-6633) and also fill out the online form "Report an Electric Service Problem."
Con Edison customers can file a claim for reimbursement for food and perishable prescription medicine that got spoiled because of a lack of refrigeration caused by a power outage.