Here’s an update on last night’s manhole explosions on East Broadway (near Samuel Dickstein Plaza). We just got off the phone with Con Edison spokeswoman D. Joy Faber, who said workers are making repairs on corroded electrical cables today and continuing to investigate exactly what caused the blasts. She said it was not a transformer explosion (that’s what firefighters suspected last night).
Instead, Faber said, it appears to be a more straightforward case of electrical cables having been corrupted by salt used during the snow storm (the investigation will hopefully confirm this hypothesis). The phenomenon is fairly common in the city each winter. The salt eats away at and then burns the cables’ insulation, releasing flammable gases. Sometimes, but not always, explosions are the result.
Several years ago, a fire department spokesman told the New York Times there are thousands of manhole incidents each winter in New York, and they appear to be on the rise. The explosions can release deadly carbon monoxide (which explains why firefighters and cops were keeping residents far away from the scene last night). There’s also the risk of flying manhole covers (which weigh 300 pounds) injuring bystanders. No one was hurt last night, but Faber said a car was damaged.
Given the dangers, is there an alternative to using salt on the roads? The Times looked into that issue back in 2004:
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 (Sanitation Dept. Spokeswoman Kathy) 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. Ms. Boden said that Con Ed was also experimenting with two other potential solutions: wires with thicker insulation and manhole covers with higher ventilation. The new ”double jacketed” wires are less flammable and more durable, but they have been installed in very few places in the city and are only being introduced when old wires fail. Although around 700 of the ”super ventilated” manhole covers have been installed around Grand Central Station, Ms. Boden said it was too early to know if they would help. These covers allow smoke to seep out when there is a problem in a manhole, decreasing the pressure and the severity of any explosion. But the covers have the disadvantage that higher amounts of salt and water wash into the holes, which add to the corrosion of the wires and the likelihood of eventual problems.
One other note: Con Ed had to cut the power to the Emigrant Savings Bank, while they restore service. But the bank is being supplied with temporary back-up power in the meantime.