The scanners will be introduced in certain stations after a legally mandated 90-day waiting period, Mayor Eric Adams said.

“Keeping New Yorkers safe on the subway and maintaining confidence in the system is key to ensuring that New York remains the safest big city in America,” said Adams, who also announced a plan to send additional outreach workers into subway stations to try to get people with mental health issues who are living in the system into treatment.

Adams said officials would work to identify companies with expertise in weapons detection technology and that after the waiting period the scanners would be instituted in some subway stations “where the NYPD will be able to further evaluate the equipment’s effectiveness.”

The scanner that Adams and police officials introduced during Thursday’s news conference in a lower Manhattan station came from Evolv, a publicly traded company that has been accused of doctoring the results of software testing to make its scanners appear more effective than they are.

Jerome Greco, supervising attorney of the digital forensics unit at the Legal Aid Society, said gun detection systems can trigger false alarms and cause panic.

“This Administration’s headstrong reliance on technology as a panacea to further public safety is misguided, costly, and creates significant invasions of privacy,” Greco said in a news release.

Adams said the city would perform its own analysis of the scanners’ accuracy.

“People may have had bad experiences with this technology,” Adams, a former transit police officer, said. “What we witnessed, it’s living up to our expectations. And we’re going to do an analysis and determine, hey is it living up to our expectations.”

City officials did not say exactly where the scanners would be installed. The device they demonstrated at the Fulton Street station beeped after brief delay when a police officer with a holstered gun went through but was silent when officers carrying cellphones and other electronic devices passed through.

Overall, violent crime is rare in the city’s subway system, which serves about 3 million riders a day, but there have been two recent high-profile shooting incidents. Earlier in March, a man was shot with his own gun and critically wounded during a confrontation with another passenger. Last month, one person was killed and several others wounded when shots rang out amid a fight between two groups on a rush-hour subway car.

There were five killings in the system last year, down from 10 the year prior, according to police. There were three homicides in the first two months of 2024.

The scanner announcement came days after a fatal shove in an East Harlem subway station on Monday once again brought the issue of subway safety to the forefront.

Also on Monday, New York City officials announced a plan to send 800 more police officers into the subway system to crack down on fare evasion.

Before the latest surge, the NYPD had seized 17 guns from people stopped in the system this year, Metropolitan Transportation Authority Chair and CEO Janno Lieber said at a board meeting Wednesday.