Exploding manholes point to larger problem

Reposted from: POSTED 8:12 PM, FEBRUARY 3, 2015, BY JAMES FORD, UPDATED AT 10:14AM, FEBRUARY 4, 2015
PARK SLOPE, Brooklyn (PIX11) — Eighteen hours after a manhole explosion seriously injured a passerby, a similar explosion a few blocks away forced an evacuation, and left residents without power.

The close proximity of the two fires is unusual, but the frequency of manhole explosions during snowy, slushy winter weather is not. Still, Con Edison calls the hundreds of fires in its equipment a sign of improvements in its system.

The latest Park Slope manhole explosion happened just after 4 a.m. Tuesday on Sixth Street near Sixth Avenue. The ball of flame that shot out from the manhole fully engulfed one car, totaling it, and melted the plastic rear bumper of another.

According to Con Ed and the FDNY, flammable gases built up in the chamber underneath the manhole cover, resulting in the blaze that consumed the Mazda parked over the manhole. The smoke from the fire also filled a half dozen homes downwind from the flames. The carbon monoxide levels in the homes was deemed by firefighters to be so dangerously high that they ordered the buildings to be evacuated.

Residents told PIX11 News that they were taken to a nearby idling bus that Con Ed had arranged for them to sit in to stay warm while firefighters put out the flames and vented the houses.

The Tuesday morning incident happened 18 hours after another manhole exploded three blocks away, in the intersection of Fifth Street and Prospect Park West.

“All of a sudden,” said a man who gave only his first name, Robert, who lives in the building on the south side of the intersection, “I heard a loud explosion. I personally thought it was a collapse.”

The 11:30 a.m. incident on Monday shattered windows in three different blocks nearby, and still has Sal Grillo, 71, in the hospital in stable condition after the manhole cover flew up in the air and hit him in the head. He had been transported Monday in serious condition.

Another resident of the building next to the intersection, Margaret Contorno, 91, was also injured. She was treated at a nearby hospital for wounds from shattered glass. Neither she nor Grillo was available for comment on Tuesday.

Back at the scene of the Tuesday morning explosion and evacuation, residents have now returned to their homes, but Con Ed is still trying to restore full power to the buildings.

Their situation is by no means exceptional.

In Washington Heights, there was a similar situation, with a manhole explosion and fire on Monday night, near Washington Avenue and 163rd Street, followed by another explosion and evacuation five blocks away Tuesday afternoon in the 3800 block of Broadway.

And all the manhole fires mentioned so far in this story are part of a larger occurrence of them. Since midday Saturday, there have been more than 200 explosions in manholes throughout the Con Ed system.

For its part, however, the utility points out that its system includes over 90,000 miles of cable, with more than 264,000 manholes or grates. To have fewer than 300 explosions over that broad of a network, Con Ed says is just part of the season of snow removal the region is in.

“When salt gets in [manholes], along with the water,” said Mike Clendenin, a Con Ed spokesperson, “and if it penetrates to the electrical lines themselves, you’re going to get smoke, you’re going to get fire, and you’re going to get, sometimes, get an explosion.”

Clendenin said that Con Ed has, in the past decade, replaced many solid metal manhole covers with ones that have vents in them. That allows, he said, “the gases to escape so that we don’t have explosions, or nearly as dangerous explosions as we’ve had before.”

Tuesday’s sub-freezing temperatures, said Clendenin, can be helpful to the electrical utility system because the low temperatures freeze fallen snow and ice hard, preventing the formation of salt water runoff that can get into manholes and deteriorate the insulation around electric lines, causing them to heat up and burn.

On Wednesday, however, temperatures are expected to approach 40 degrees Fahrenheit, which may in turn cause salty snow melt, thus provoking more manhole fires.

Con Ed reminded New Yorkers to call 911 or the utility immediately if they hear popping sounds coming from a manhole or street grate, or if they see smoke coming from them. Also, one should get as far away as possible from a potentially dangerous manhole or grate. The emergency number for Con Ed is 800-75-CONED, or 800-752-6633.

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