The green sludge in NYC is captivating people online, but it's not the first time. Here are 4 other times the lime-colored slime baffled onlookers.

The green substance appeared to bubble up near a sewer close to the 9/11 memorial in Manhattan.
The green substance appeared in New York City this week.Maria Noyen/Insider
  • Footage of green sludge bubbling near a sewer in New York City gained traction on social media. 

  • X's fact-checking feature, Community Notes, suggested the green hue was caused by dye. 

  • There have been other green slime incidents in recent years, including on a Michigan highway. 

A bright, fluorescent green sludge appeared in New York City this week, shocking tourists and people online.

The discussions surrounding the neon liquid sparked on Thursday after X user Dan Pantelo shared a photo and footage to his account. Pantelo said the puddle was located in the Wall Street neighborhood near the World Trade Center in Manhattan. The photo gained more than 24 million views and 4,800 comments.

"Can anybody explain this or are we just living in full blown Gotham rn," Pantelo captioned a second X post.

X's fact-checking feature, Community Notes, later suggested the mysterious sludge was actually water with green dye.

Screenshot of Community Note on X.
Screenshot of a Community Note on X.X/DanPantelo

As Insider's Maria Noyen previously reported, tourists were more concerned with the green liquid than locals.

"I have no idea what it could possibly be. But it's definitely not good, whatever it is," a tourist named Richard Johnston told Insider.

Locals, on the other hand, were unfazed. One 17-year-old named Diego told Insider that "knowing New York, stuff happens. Weird stuff happens. People just walk by and don't pay attention to it."

While Pantelo's post inspired a spirited debate online, it's not the first time people have been fascinated with green sludge.

In May 2017, an Instagram user shared a photo of green sludge in Midtown Manhattan

Gothamist reported that the liquid was discovered in Midtown, a neighborhood in Manhattan.

The outlet speculated that the green color may have been caused by antifreeze. Regardless, Instagram user @kenobibear, who originally shared the photo, tagged the location at the Port Authority bus terminal. The photo shows the liquid gathered at a street corner while pedestrians strolled by. In the caption, @kenobibear wrote the liquid left people unfazed.

"This neon green sewer water did not give anyone the slightest pause this morning," they wrote.

Two months later, New Yorkers spotted a green puddle at a popular subway station

The Gothamist reported a second mysterious green puddle in July 2017 at the 34th Street-Herald Square station.

An MTA spokesperson told Gothamist the green color was intentional.

"The color is from a green dye that was placed in the water source in the area to help locate a known water leak in that location," the spokesperson said. "The structure that is above that water leak is a water pipe. It has been cleaned."

Environmental officials weighed in after a green liquid seeped onto a Michigan highway in December 2019  

The New York Times reported that the green liquid impacted traffic and prompted lane closures to allow for hazard cleanup on Interstate 696 outside Detroit in December 2019. Jill A. Greenberg — a spokeswoman for the Michigan Department of Environment, Great Lakes, and Energy — told the outlet the substance was likely hexavalent chromium.

Hexavalent chromium is used in manufacturing, but it is known to cause cancer, according to the National Institute of Environmental Health Sciences.

The spokeswoman told NYT that hazardous material crews determined that the public's drinking water and air had not been contaminated.

In November 2020, a sinkhole in Toronto gained media attention after green liquid became visible from the road 

CityNews Toronto reported that a bright green liquid emerged from a sinkhole in the city's downtown area in the fall of 2020.

A city official told the outlet that the green liquid was a standard procedure during repairs, which involved dying the water.

"In order to determine if the sinkhole is connected to the underlying sewer, a dye test was conducted using a green non-toxic dye, which is added to the sinkhole while monitoring the closest manhole downstream to look for traces of the dye in the sewer," the spokesperson said.

Read the original article on Insider