Body scanners debut this week to access New York City subways 

Controversial body scanners debuted Friday in the New York City subway system to search for concealed weapons, Mayor Eric Adams said.

Under the plan, randomly selected passengers must walk through a machine in order to enter the subway system. Those who refuse won't be allowed to enter the subway system through that entrance.

But any passenger who sets off the machine — which has a high false-positive rate — must agree to be searched by a police officer, under the city's plan.

Adams said earlier this week that the scanners, which he announced in March, would debut this week, by Thursday or Friday.

"I'm really excited about this, just the potentiality that we could identify someone carrying a gun before they enter the system. I like the results from the testing. They did several thousand tests," Adams said.

At a Friday afternoon news conference announced shortly before it began, Adams said the pilot had begun and would continue for 30 days. 

"We will not be announcing in advance where or when we are doing this," Adams said. "It could be every fifth, 10th or 20th person. It will vary from day to day."

A scanner was in place Friday at the Fulton Transit Center, according to Adams spokeswoman Amaris Cockfield. The center serves the 2, 3, 4, 5, A, C, J, R, and Z trains.

Eugene Resnick, a spokesman for the MTA, referred an inquiry to the NYPD.

The scanners are in use at sports stadiums, museums and other public venues, though at those places, setting off the scanner doesn’t necessitate a mandatory police search.

The scanners are controversial because of the high false-positive rate during test runs and because of the mandatory police search if the scanner goes off. Earlier this month, Adams said that crime is down overall in the subway system.

Separately, the New York Civil Liberties Union and the Legal Aid Society threatened to sue the NYPD if the scanners are put into place, calling them "invasive, error-prone, and time-consuming."

The group said in a statement: "Forcing New Yorkers to undergo baseless scanning in order to ride the subway violates their Fourth Amendment rights, which protect people against suspicionless searches and seizures from the police."

Scanners that Adams and the NYPD have demonstrated are from the company Evolv. The scanners use ultra-low-frequency, electromagnetic fields to detect concealed weapons, paired with artificial intelligence technology that is ostensibly programmed to distinguish between weapons and benign objects.

The company is being probed by the federal government, including the Federal Trade Commission, over claims that the scanners don’t work as claimed.

The NYPD has been conducting random bag checks for nearly 20 years, a policy which followed a transit system terrorist attack abroad. The threat of an attack in New York was the stated justification for the "special needs" exception to the Fourth Amendment. 

It remains to be seen whether that exception can be applied to prevention of shootings. 

By Matthew Chayes

matthew.chayes@newsday.comchayesmatthew

Matthew Chayes, a Newsday reporter since 2007, covers New York City.