Imagine this: you’re walking in downtown D.C. and suddenly, you notice a sidewalk grate ahead of you. Do you confidently walk right over the steel bars, hardly noticing the looming abyss beneath, or do you step to the side to avoid walking over the murky depths? 

Sidewalk grates are a regular part of the infrastructure of a city — but for some Washingtonians, they provoke one of their greatest fears (pun intended). That fear may have seemed irrational until last week, when a grate collapsed beneath a woman walking in Southwest D.C., and the story quickly went viral.

Below grade rescue 800 block 4th St SW. Adult female fallen approximately 10 feet down in an air well. She is being treated for injuries and working on plan for extrication. pic.twitter.com/ZQ2Zmqi299

— DC Fire and EMS (@dcfireems) March 23, 2022

We wanted to know more about the incident. Here’s what we learned.

A team from D.C. Fire and EMS arrived at the Potomac Place Tower apartment building in Southwest D.C. on Wednesday March 23rd at 5:23 p.m., where the woman had fallen ten feet into a building’s air shaft. After about 30 minutes, DCFEMS managed to lift the woman out and she was taken to a nearby hospital to be treated for serious but non-life threatening injuries. The grate is on the private property of Potomac Place Tower, which did not respond to a request for comment.

How many sidewalk grates are there, and why are they there?

According to DCFEMS, the woman fell into a private air well, which is a building feature usually used to circulate light and air.

On public property throughout D.C., there are more than ten thousand sidewalk grates, some of which cover infrastructure that power the city. In 2000, a woman walking on M St. NW dropped her engagement ring down one of PEPCO’s sidewalk grates. Four workers spent hours sifting through the muck below to retrieve it for her. 

According to a WMATA spokesperson, there are approximately 400 grates that are part of the WMATA system throughout the region. Most of Metro’s grates are either fan shafts (designed to help cool tunnels and moderate air movement) or vent shafts (short for ventilation), and about 15 of them are also designated as routes for emergency exit from the tunnels. 

Does anyone check that the sidewalk grates are safe?

Metro performs structural inspections on the system’s grates every three years, according to a spokesperson. The vent and fan shafts are cleaned quarterly. 

On private property, it’s up to the property owner to ensure the grates are safe, according to a spokesperson from DC’s Department of Consumer and Regulatory Affairs (DCRA). There is no requirement that they be checked or inspected, though they do have to be installed following code that requires the grates be able to hold 60 pounds per square foot. DCRA can also cite deteriorated steel or aluminum grates, if that deterioration is visible. 

How common is it for sidewalk grates to collapse?

A spokesperson from D.C. Fire and EMS said this is the first time he’s heard of a sidewalk grate collapse in the five years he’s been at the agency. No other city agencies had record of such an incident either, but it has happened in the last ten years nearby. In the Ballston neighborhood of Arlington in 2013, a man in his 50s fell into a ventilation shaft when the steel grate above it collapsed. He was also taken to the hospital with serious but non-life threatening injuries. 

Sidewalk grates have collapsed in other cities, including in Chicago in 2016 and Manhattan in 2007, but that’s not the only danger pedestrians strolling down the street might encounter. 

What other potential (though unusual) dangers do sidewalk grates present?

There had been no recent incidents in our region involving sidewalk grates until last week, but other cities have seen some dramatic accidents. Last year, a man walked over one of power company Con Edison’s grates in Queens, New York at exactly the wrong time, when a fiery explosion shot up from beneath him. He suffered second degree burns. 

There have also been cases of dogs being electrocuted when walking over steel grates or metal-covered manholes, like in January of this year in Brooklyn, New York, when a 4-year-old dog named Lala was shocked and killed. The incidents can happen after snowstorms, when salt can erode cables, causing a charge to pulse through metal on the ground. People can be electrocuted, too. 

We’d be remiss not to mention another scary incident, though this one involved a portion of the sidewalk crumbling beneath a man: In the Bronx in 2020, a man plunged 12 to 15 feet into a hole swarming with rats. 

If it’s so uncommon for sidewalk grates to collapse, why are so many people scared of them?

“I have always feared these and walk around them. Now i feel justified,” @erickmiles wrote on Twitter last week. “Precisely why I will awkwardly and sometimes rudely stop and/or sidestep to avoid,” @mastodfow wrote. “My years of zig zagging around these feels validated,” @wvabwilson wrote. “OMG this is officially NOT an irrational fear,” @bholler6 wrote.

In fact, humans are often more scared of things that are unlikely to hurt us than those that are. Many people have a fear of flying, but far fewer are scared to get into a car, even though more people die every year in car accidents than in plane crashes. Shark attacks are extremely rare, but that fear keeps some people out of the water.

Human beings also learn by observation, so perhaps we are influenced by the behavior of others. Scientists theorize that you can pick up fears from others, especially as a child witnessing adults reacting fearfully. The dingy depths beneath sidewalk grates also represent a scary unknown, just like the darkness below your childhood bed.