How Not to Get Hit by an Exploding Manhole Cover
While the chances of being hit by an exploding manhole cover are low, they are not zero. According to the 2021 New York City Mayor’s Leadership Report, the New York City Fire Department responded to 261 instances where manhole covers were displaced by explosions in FY2021. It’s not just New York City’s problem; Manhole covers explode all over the country. Chicago has received more than 3,500 complaints about missing manhole covers and gratings since 2016. A manhole cover explosion was recently caught on camera in Boston . And one manhole cover explosion recently even destroyed a car in Miami .
So, what do you do to make sure that an exploding manhole cover doesn’t get in your way? By watching for a few warning signs, you can spot a manhole cover explosion before it happens and warn those who can prevent it.
What causes a manhole cover to explode?
Manhole cover explosions mostly occur during the winter months, although they can explode all year round. It all starts when the salt used to clear snow mixes with water and runs down a manhole, according to New York-based electricity, gas and steam supplier Con Edison . Salt water, which conducts electricity, then submerges electrical cables and generates heat by destroying the cable’s insulation layer by coming into contact with a live wire. This will then produce gas and smoke when the insulation burns, leading to conditions where a spark can form from the wires, igniting the accumulated gas.
The explosion can lift the hatch up to 50 feet above the ground , becoming an extremely dangerous projectile for anyone in the area. If you’re looking for a detailed animation of this process from start to finish, the Weather Channel has you covered .
How to spot an impending explosion (and what to do if you see one)
The circumstances that lead to the explosion of the manhole cover add up slowly over time. If you ever see smoke coming from the manhole, you should back away immediately and call the emergency services to call the fire department. Con Edison spokesman Sidney Alvarez told Bklyner: “I know [people] take out their phones and shoot videos. If they could call 911 or us first and then take a video, that would be better. The sooner they call us, the sooner we can get out and secure.”
If you are not sure if the gas you see from the manhole is smoke or just steam, it is still a good idea to report it , as uncorrected leaks from steam systems can also pose a public safety hazard. If you see a missing manhole cover on the street or highway, don’t call 911, but instead report it to the local authorities. In addition, Con Edison also recommends keeping pets away from lampposts, grills, and manhole covers during “after a thunderstorm” periods.