San Francisco police officers could be wearing cameras as early as Aug. 1 after their union voted unanimously Tuesday to support a set of rules for using the devices that seeks a middle path on whether officers should be allowed to view footage before filing reports on critical incidents such as shootings.

The Police Officers Association agreed on a policy requiring officers to provide an initial statement of facts before screening body-camera footage following in-custody deaths as well as officer-involved shootings like those that have stirred outrage, a federal review and the recent resignation of the police chief in San Francisco.

Union officials had previously fought to allow officers to view the videos before issuing any statement, saying stressful situations can affect memory and that not allowing officers to view footage set them up for “gotcha” moments if their memory did not perfectly match what was captured.

Law enforcement watchdogs, however, argued that officers allowed to watch video of an incident could adjust their statements, limiting the power of body cameras — which have been adopted by police around the Bay Area and the country — to increase transparency and accountability.

Under the union’s proposal, officers will be allowed to view the footage after providing an initial statement.

“This is originally what the ACLU wanted when we were in working groups,” said union President Martin Halloran. “The Office of Citizen Complaints agreed with them, along with the public defender’s office and the San Francisco Bar Association. They wanted a state-of-mind statement prior to the members viewing the video. I wasn’t completely sold on that, but since that time, we have spoken to experts in the field and we decided that this will be more transparent and will allow officers to view these videos before they’re in a full-blown interview.”

Policy a compromise

“This is a compromise that we worked out and we believe it will be acceptable to both the Police Commission and to those stakeholders.”

With Tuesday’s vote, the final policy will go before the city Police Commission on Wednesday for discussion and possible action, bringing an end to more than a year of debate. Mayor Ed Lee said he hoped that body cameras would be rolled out within 60 days of a final vote.

“This is a big shift, a big movement for our public safety, and I’m very, very happy to see that the POA has endorsed this and embraced this,” Lee said Tuesday. “This is the first of a lot of reforms we have to do. This is a game-changer. This is really going to change what happens out there.”

Lee announced in May 2015 that he was setting aside more than $3 million in the city budget to equip 1,800 officers with body cameras. The announcement came as protests swept the nation following several highly publicized police killings of unarmed black men, and in San Francisco, racist and homophobic text messages, exchanged among several officers, emerged out of a federal corruption case against a former police sergeant.

In the months that followed, the calls for transparency and accountability only increased in San Francisco, with five more fatal officer-involved shootings of people of color and another scandal involving officers allegedly sending racist and homophobic text messages.

The Dec. 2 fatal shooting of Mario Woods in the Bayview, which was captured on videos taken by bystanders, incensed community members and prompted a U.S. Department of Justice community policing review. The Police Commission also reopened the department’s use-of-force policy. After the May 19 shooting of Jessica Williams, Lee asked Police Chief Greg Suhr to resign.

‘Urgency’ for reform

Lee acknowledged that there was “an urgency” for reform and transparency with the events of the past months, but Police Commission President Suzy Loftus refused to roll out body cameras without proper policies developed by people who would be most affected by the technology.

A working group included the police union, the public defender’s office, the San Francisco Bar Association and alliances within the police force, such as the black officers’ group Officers for Justice. They discussed the policy for several months, often diverging on when officers should view footage.

In December, the Police Commission voted on a policy that allowed officers to view videos at the discretion of the chief, sending the proposal to the police union for negotiation — as must be done under department policy.

“I think the point of having body cameras, it helps determine the truth,” Loftus said. “Any investigation is ultimately a search for the truth, and I think that the question of viewing has to do with if there is a way to set it up while also preserving an officer’s immediate recollection of what happened.”

The union’s agreement, she said, “appears to be consistent with the overall goal of additional transparency and making sure these cameras get to the truth of what actually happened.”

The version the union sent back to the Police Commission — allowing officers to view footage after they issue an initial statement — was a compromise, but one that civil rights activists say needs to be clear in the written policy.

“The devil is very much in the details,” said Catherine Wagner, a staff attorney for the ACLU of Southern California. “What does that initial statement include? I think what you would want is to essentially take an officer’s statement, a full statement, about what they remember of the incident, and then watching the body camera footage and providing additional commentary should be extra.

“The initial statement shouldn’t be so bare-bones,” she said, “that they’re waiting to watch the footage to flesh out information that should be in their memory.”

Deputy San Francisco Public Defender Rebecca Young, who helped draft the policy and was against allowing officers to view the footage, pointed to a recent incident in which a city officer was caught allegedly perjuring himself in federal court after video was released.

Acting chief weighs in

“We’ve seen from the most recent incident ... how important it is for officers to not be allowed to shape their testimony according to a video, but according to the actions that they took based upon what they were seeing,” Young said. “I don’t understand why it’d be a problem if the officers are telling the truth.”

Acting Police Chief Toney Chaplin, who highlighted the body cameras as one of his top priorities when he took over the position May 19 from Greg Suhr, said the coming roll-out “moves us firmly into 21st century policing.”

“We welcome this agreement with the Police Officers Association,” he said. “We look forward to the deployment of the cameras in the near future.”

Vivian Ho is a San Francisco Chronicle staff writer. Email: vho@sfchronicle.com

Twitter: VivianHo