The Portland City Council delayed taking action Monday on a proposal to prohibit city employees from using facial recognition technology.

The ban was proposed by City Councilor Pious Ali, who said that the technology often misidentifies women, people of color and children. He also noted that the police department told the school board that it might use the technology with body cameras at some point.

“It’s very invasive and it tramps on people’s freedom of speech,” Ali said. “I am bringing this forward to make sure no city staff, employee or agent uses that, to protect the privacy of our citizens.”

City staff has said facial recognition is not currently being used. Several councilors said they’d prefer to refer the proposal to a committee once the new mayor, Kate Snyder, takes office and the council has a chance to have its goal-setting session, especially since there are no imminent plans to implement the technology.

City Councilor Jill Duson said that, as a woman of color, she is “very afraid” of the technology, but she didn’t think the city should ban it without studying it.

“I’m very afraid of this technology, but despite that, I think our city has shown an ability to look at these policies and tailor them to what makes sense for our city,” she said.

The council will take the issue up again at its Jan. 6 meeting.

Portland City Councilor Pious Ali and fellow Councilor Brian Batson are proposing that Portland ban the use of facial scanning technology by city employees, including the police department. Gregory Rec/Staff Photographer

Only a handful of people spoke during the public hearing. All but one, an attorney representing Microsoft, supported an outright ban.

Brendan McQuade, an author and professor of criminology at the University of Southern Maine, said the technology can lead to false identifications and also has an “astronomical” risk for abuse, since private cameras can be networked and track people’s movements.

“The risks associated with facial recognition technology are a significant enough threat to justify banning the technology,” McQuade said.

Alexander Price, an attorney for Pierce Atwood representing Microsoft, urged the city to regulate the technology, but not ban it.

“Microsoft understands that the use of new technologies poses challenges that call for a thoughtful discussion amongst all stakeholders, and we stand ready to serve as a resource to help those discussions progress,” Price said.

Facial recognition has been around for decades, but technological advances in recent years, especially in three-dimensional imaging, have made it more ubiquitous. While two-dimensional images require ideal lighting and the subject to be facing the camera, new technology can allow identification of someone turned 90 degrees from the camera.

It works by essentially mapping a person’s dominant facial features, such as eye shape and spacing, as well as jaw and nose lines. The software measures the distances between dozens of reference points, creating a unique profile similar to a fingerprint.

The profile is then compared to the faces in existing databases, such as those that contain driver’s licenses, state IDs, passport photos or police mugshots.

More advanced programs also can conduct an analysis of skin texture to increase accuracy and, in some cases, account for different facial expressions, facial hair or eyeglasses.

Facial recognition technology is used all over the world, with applications ranging from airport and border security to a soccer team in Denmark that uses it to identify unruly fans.

Perhaps the most extensive deployment is in China, where authorities are using it to monitor the Uighurs, a largely Muslim minority ethnic population.

In the absence of federal laws governing facial recognition, some states and local municipalities are taking action to regulate its use.

San Francisco became the first city in the U.S. to ban use of the technology in May. Since then, Oakland, California, and Somerville, Massachusetts, have followed suit. And Cambridge, Massachusetts, is considering enacting a ban on use by its city government.

The state of California this fall passed a three-year ban on using facial recognition technology in police body cameras in the state. And Massachusetts, which the ACLU says has used facial recognition since at least 2006, is considering a moratorium on facial recognition and “other remote biometric surveillance systems.”