James Martin/CNET

San Francisco this month became the first US city to prohibit police from using facial recognition technology. Advocates want to make sure it won't be the last.

Using San Francisco's ordinance as a model, activists are pushing for local legislation elsewhere to ban the technology, a form of artificial intelligence that matches faces and tracks people. Municipalities mulling bans include San Francisco neighbors Oakland and Berkeley, and Somerville, Massachusetts. With the victory in San Francisco, more cities could join the list.

The efforts don't stop at the local level. In California, a push to ban facial recognition from being used in body cameras has made it to the state senate. Lawmakers in Washington have proposed a statewide facial recognition bill. Two US senators have introduced a bill that would prevent companies from tracking you through facial recognition.

"We fully expect this type of legislation to be taken up in other communities," said Matt Cagle, a lawyer at the American Civil Liberties Union of Northern California, which was instrumental in drafting the San Francisco legislation and organizing community support for the ban. Cagle says he's heard from state legislators "who are interested in seeing how this prohibition on face surveillance could be applied to body cameras first, or in schools."

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The grassroots effort to curb facial recognition technology comes as police, stores and airports install systems to help them solve crimes, prevent shoplifting and speed boarding of flights and cruises. The technology has become ubiquitous in some Chinese cities, where it's even being used to identify pandas. Big tech companies, especially Amazon, have an interest in selling facial recognition technology, as well as using it in stores.

The rapid rise of the powerful technology has prompted a backlash. Lawmakers, experts and activists have pointed to privacy issues tied to facial recognition monitoring, as well as to civil liberties concerns. Facial recognition could scare people away from public protests if the technology is tracking people, experts warn.

"You could be at a rally supporting gun rights or protesting gun violence," Rep. Elijah Cummings, the Democratic chairman of the House Oversight Committee, said this week during a hearing on facial recognition. "In all of these cases, the government can monitor you without your knowledge and enter your face in a database that can be used in unrestricted ways."

We fully expect this type of legislation to be taken up in other communities. Matt Cagle, ACLU of Northern California attorney

Accuracy and bias are among the biggest concerns about the technology. Researchers have found facial recognition to have problems recognizing women, as well as people with darker skin. Researchers also say that police departments misuse facial recognition technology, often manipulating photos to generate matches or swapping in celebrity lookalikes to find suspects.

And there's little in the way of supervision or oversight, critics say.

Supporters of facial recognition argue that it helps with police investigations and deters crimes. Despite the technology's flaws, proponents say, facial recognition technology can be useful.

Cedric Alexander, the former president of the National Organization of Black Law Enforcement Executives, told lawmakers that banning the technology would be a mistake, though he stressed that few agencies have proper oversight to stop misuse.

"I'm not sure if a total moratorium on this is going to be an answer, because we still have a homeland we have to protect, and because there is still some value in facial recognition," Alexander, formerly a federal security director at the Transportation Security Administration, said in testimony Wednesday.

Though many law enforcement officials support facial recognition, the technology's many issues have led to a growing call for a moratorium. States aren't waiting for Congress to pass a federal bill regulating the technology, and many legislators are looking to take action themselves.

A number of local efforts are leaning on the language in San Francisco's ordinance, which is similar to the ACLU's Community Control Over Police Surveillance (CCOPS) model bill. Cagle, the ACLU of Northern California lawyer, says it can be applied to other cities.

Laws and ordinances don't pass, however, unless elected officials support them. So the ACLU is also working on a toolkit to explain to communities how they can push for surveillance oversight in their own cities. The effort will be different for each region because local legislatures have their own priorities and concerns, he said.

A rough guide

The San Francisco ban was a much-needed boost for efforts to pass moratoriums in other cities, says Jelani Drew, a campaigner at Fight For The Future, a tech-focused nonprofit. The organization is encouraging people to reach out to local lawmakers and ask them to ban facial recognition in their own city.

Drew says the group's effort has gained traction since the San Francisco ban.

"We're really hoping to get people energized around using San Francisco as a grounding point, to believe that this can really happen," Drew said. "The next step is that more people go to their legislatures and get a general path on how to work with their communities."

Community effort, Cagle stressed, is one of the most important components of getting a facial recognition ban passed.

Georgetown Law Center on Privacy & Technology

Fight for the Future, along with groups like Color of Change, the Electronic Frontier Foundation and the Freedom of the Press Foundation, were a part of the ACLU's coalition in San Francisco that worked with city officials to pass the law. These efforts included speaking with elected leaders, attending community meetings, making calls and getting support, he said.

"It is absolutely necessary that there be community support and people in the community that want to do something about it," Cagle said. "This would not have passed in San Francisco without the diverse communitywide coalition showing up at meetings, making calls."

Drew says Fight for the Future is working with activists across the country, looking to spread the word on how facial recognition affects people's privacy. But it won't be simple. Proposed laws can often languish in community legislation, and momentum doesn't last forever.

In San Francisco, the ACLU's strategy called for reaching out to elected officials, finding local supporters and working with lawmakers on drafting legislation. The main factor, however, was persistence. The ACLU worked with San Francisco lawmakers for more than a year to get the ordinance passed, Cagle said.

"Tenacity is a key thing," Cagle said. "It takes time and tenacity."