The new technology was installed at Fulton Center subway station in Lower Manhattan.
It's part of a 30-day pilot program intended to keep guns, knives and other weapons out of the transit system.
Mayor Adams says he's determined to put the technology to widespread use.
"If you will speak to the average subway rider, they will state they don't want guns on their system. And if it means using scanners, then bring the scanners on," Adams said.
The city will set up freestanding screeners to spot guns and track how the system impacts normal commuter flow.
The way the system works is that it generates an invisible electromagnetic field. When you move through the system, you disturb that field and allows the system to detect concealed weapons.
The technology knows the difference between a gun and a cell phone.
In a demonstration earlier this year, officers with concealed handguns walked through and a computer screen pinpointed exactly where the guns could be found.
The city is using Evolv Technology's weapons detection system, the same technology in place at Citi Field.
Although this technology is less intrusive than airport security and commuters do not have to empty their pockets or remove their belts and shoes.
The scanners will not be deployed everywhere., but police commanders believe the impact could be substantial.
Critics say the technology will cause congestion at busy stations and are worried about an invasion of privacy.
In response to Mayor Eric Adams' announcement, the New York Civil Liberties Union (NYCLU) and the Legal Aid Society (LAS) released the following joint statement:
"With this misguided, fraught, and invasive technology now in effect, we are in the process of preparing litigation to protect the constitutional rights of all New Yorkers. New Yorkers did not consent to give up their rights or be NYPD guinea pigs for over-hyped and error-prone surveillance tech. We are prepared to protect the right of all subway riders to be free from NYPD intrusion and harassment."
Mayor Adams and MTA officials announced that subway crime in the city has been trending downward.
Newly released data from the NYPD shows subway crime is now down nearly 8% so far in 2024 compared to the first six months of 2023.
Adams credits the reduction in crime to the additional cops underground cracking down on quality-of-life issues and working to prevent violence.
ALSO READ | Meteor may be responsible for loud boom heard across NYC and NJ
Could meteor be responsible for loud boom heard in NYC, northern NJ
----------
* Get Eyewitness News Delivered
* More New York City news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube