As BART police Sgt. Michael Williamson made his usual rounds outside San Francisco’s 16th Street Station one recent gray morning, amid scores of commuters who poured up the steps from the underground railway, a woman, barefoot and twitching, sat to the side of the entrance and pulled out a glass pipe.

Years ago, an officer might have searched the woman before taking her to jail for drug possession. By law, officers today still could. But law enforcement agencies in cities like San Francisco have begun shifting tactics when it comes to low-level narcotics offenses, viewing them more as a public health issue, driven by addiction rather than criminal intent.

Soon, San Francisco will see this change taken a step further. The Department of Public Health is working with the city and BART police forces, as well as the district attorney, the public defender and the nonprofit Drug Policy Alliance, to launch a program that would see officers directly divert many drug offenders to treatment rather than arrest them.

Modeled on Seattle program

Though the details of the program must be solidified, it would be modeled after an initiative launched in Seattle in 2011 called Law Enforcement Assisted Diversion, or LEAD. The Seattle effort has been lauded by the Obama administration and implemented in other cities, such as Santa Fe, N.M., and Albany, N.Y. The San Francisco program would be called Assistance Before Law Enforcement, or ABLE.

“Substance abuse and addiction is a brain disease, and it has a high chance of relapse,” said Barbara Garcia, the city’s director of health. “It’s like diabetes, not like a broken ankle — it takes constant care, and for many of our clients, it’s there for a lifetime. What we want to do is interrupt this behavior by making sure people get an offering of service. We want to make sure they have an opportunity to make a change, at a time when the police are getting more engaged in helping people get into services.”

Under the programs, officers who have probable cause to cite or arrest people with drugs instead offer them an option to get treatment. In San Francisco, such people would be immediately taken to a Department of Public Health intake site, where they would work with case managers to create an individualized treatment plan.

If they chose treatment, and followed that path for a specified amount of time, the arrest or citation would go away. If they stopped complying, their case would be referred to the district attorney’s office.

“Where the program makes the biggest leap is by offering the treatment at the front end rather than at the end,” said Public Defender Jeff Adachi.

He noted that many people who get arrested are held in jail for days or weeks, and make a series of court appearances, only to end up being ordered to an addiction program.

“You start adding up the money, and you think, maybe treatment is a better alternative,” Adachi said. “If you offer that up front as opposed to 60 days later or 30 days later, it just makes sense.”

San Francisco officials have spent the past few years studying the Seattle initiative and are still hammering out the logistics, such as determining which crimes would qualify. But the agencies involved have agreed to launch the pilot program in two areas known for high drug activity: the Tenderloin neighborhood and BART’s 16th Street Station.

“I think based on the experiences in Seattle, it is going to work very well,” said District Attorney George Gascón. He pointed to a University of Washington study released last year that found program participants in Seattle had a 60 percent lower likelihood of getting arrested again over a six-month period.

A study by the same University of Washington team found that the cost of the Seattle program averaged $532 a month per person. While it’s not known how many people could qualify for the pilot program in San Francisco, Garcia said the city can handle them — and in any event it has the ability to add services if needed.

“Many of these people are already in these services,” she said.

Police express concerns

While the effort seems to be gaining support in San Francisco, some police advocates have concerns about such programs overwhelming officers.

“Why is it always left to the police officers, who are already overburdened, over-scrutinized and underpaid, (to be) the court of last resort for every social ill that exists in San Francisco and beyond?” said Jim Pasco, executive director of the national Fraternal Order of Police.

“When we reach a desperation point, rather than saying we have to really buckle down and fix these really hard things, they say, ‘Let’s give the cops the authority to put them in a diversion program or cite them.’ That’s not the answer,” he said. “The answer is to keep them from being addicts in the first place. This is a Band-Aid. It’s helpful, but it’s a mask over the failures of city government.”

Martin Halloran, president of San Francisco’s police union, said, “We are closely watching the development of the policy and are keeping an open mind about it.” San Francisco police officials could not be reached for interviews about the program.

BART Police Chief Kenton Rainey said he thinks the program will benefit the public as well as his officers.

“In our stations, we’re constantly coming in contact with probably the same 30 or 40 people,” Rainey said. “It causes a drain on all our services, when you’re dealing with the same person over and over and over again and everybody is just passing them along instead of treating what is really ailing them, not just the symptom. Why don’t we treat the person if we can?”

Laura Thomas, deputy state director of the Drug Policy Alliance in California, said it is time to stop putting police officers “in the position of having to address a lot of our major social and economic problems” without proper training or tools to make things better.

“The war on drugs has been a very, very expensive mistake,” Thomas said. “It’s ruined individuals’ lives, it’s torn families apart, and it’s destroyed communities through mass incarceration. I think the United States more broadly is having this realization that what we have been doing hasn’t worked.”

Reducing officers’ workload

Williamson, the BART sergeant at the 16th Street Station, said he saw the program as a way to reduce the workload of officers who spend much of their shifts dealing with issues that often stem from drug abuse, such as fare evasion, panhandling and public urination.

He said it would be an extension of what he and his fellow officers are already doing. The BART officers based out of San Francisco, he said, are familiar with the two-block walk to the Mission Neighborhood Resource Center, where they often offer to escort people in crisis. They also hand out pamphlets to loitering homeless people in a bid to steer them toward resources.

‘It’s a tough balance’

And since 2012, Armando Sandoval, BART’s civilian crisis intervention training coordinator, has been helping officers. On a recent morning outside the 16th Street Station, he wore plain clothes as he and two officers approached a disheveled woman sitting on a bench, surrounded by bags.

“It’s a tough balance,” Sandoval said. “There is human decency that you want to bestow, but you have to consider the willingness, the capability, of the person you’re trying to bestow that on. Officers have to be respectful of that. We’re in a new era now.”

He said each contact is important. If officers can’t persuade someone to accept help one day, they may still build the trust needed to make a breakthrough later.

“Think about it,” Sandoval said. “If one officer makes just one good, solid contact in one year — in a 200-plus agency, that’s 200 contacts in one year.”

When Williamson approached the barefoot woman with the glass pipe, it was not her breakthrough day. But for Williamson, that didn’t matter.

The pipe was clean and had no residue in it. Williamson asked her how she was doing before gently reminding her that she couldn’t use the pipe there.

“You know to yell if you need something,” he told the woman. “All you have to do is ask.”

“I know,” she said as she walked away. “I know you.”

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