At the height of a heroin epidemic in Vancouver, British Columbia, Inspector Bill Spearn — then a rookie cop — was assigned to a beat in the heart of the crisis.

It was 1996, and though he had been responding to overdose after overdose in Downtown Eastside, one of Canada's poorest postal codes, Spearn wanted no part of the harm-reduction measures the city was considering to save the lives of people in addiction.

A safe injection site, where drugs could be used under medical supervision, was out of the question: "I thought it would be a big magnet," he told a crowd at Temple University Medical School on Monday night. "I thought it would empower people to use drugs." A few years later, with the debate still raging, he left the neighborhood for another position in the police department.

In the meantime, Vancouver did open a safe injection site in the Downtown Eastside, the first in North America. Years later, Spearn was promoted to sergeant and found himself on the same patrols he walked as a rookie. The first thing he noticed, he said, was that no one was overdosing on the street.

"The light bulbs started going off in my head: This might not be such a bad idea," he said of the safe injection site.

These days, Spearn heads his department's organized crime task force, and in his spare time travels across Canada talking about how police can get on board with harm reduction policies. He came to Philadelphia at the behest of the Public Health Department, which has been holding informational meetings around the city about its plan, announced earlier this year, to sanction a safe injection site. It was Spearn's first time speaking about these sites in the United States, where the concept is controversial.

Before Monday night's community meeting, Spearn spoke with City Council members whose districts include Kensington, where drug use is most visible and most concentrated, and the police officers who patrol the area. Police Commissioner Richard Ross spent an hour with Spearn. Ross said talks with that city's police chief "moved the needle" for him, though he's still not in support.

"I'm still at a point where you have to convince me," he said Tuesday. "I'm not at the point where I'm like, 'Hell no, get away from me,' which is where I was."

Still, Ross said, he remains concerned about how his officers would police a safe injection site — and about how community members would react to a site in their neighborhood. And at least one harm-reduction measure Canada is trying would be inconceivable in Philadelphia, Ross said.  Spearn supports a pilot program in Vancouver where people entrenched in heroin addiction are prescribed medical-grade heroin as a form of treatment.

"I think that lost a lot of people. It's a bit much," Ross said.

Spearn said after Monday night's meeting that he had been impressed with the local police department's willingness to listen: Philadelphia was one of the first American cities to send officers to tour Vancouver's safe injection site. And he was staggered, he said, by the number of deaths in Philadelphia. About 200 people a year were dying of overdoses in Vancouver by the time the city opened a safe injection site; an estimated 1,200 people died of overdoses in Philadelphia last year.

"The problem is much worse here — and it's not just a Vancouver problem, it's not just a Philadelphia problem, it's a problem that affects the entire continent, and it's spreading," he said.

Spearn and Sarah Evans, who was the first director of Vancouver's first safe injection site, Insite, and now works in harm reduction in New York, fielded questions from a crowd of about 75 Monday about how the site operates, who it serves, and how Evans and her staff wrangled the legal questions surrounding the site.

Vancouver's site was able to operate under an exemption from the country's controlled substances law, Evans said. Still, she stressed: "Every site in the world has to address that question: Can I do this without getting arrested?"

For Spearn, the sites' benefits have been clear: they've cut back on overdose deaths and gotten more people into treatment. But the sites are not a panacea, he said — Vancouver's treatment system has not kept up with its harm reduction methods. The police department has begun advocating for treatment on demand, meaning that people who ask for help are immediately taken to a treatment facility.

As in Philadelphia, fentanyl — a synthetic opioid far more powerful than heroin– has made its way into Vancouver's drug supply, sometimes without the user's even knowing it has been added. Overdose deaths have spiked past the levels he saw as a rookie in the '90s; about 80 percent of cases involved fentanyl. But Spearn shudders to think what the death rate would have been without the city's safe injection sites: Insite alone, he said, revives seven to eight people a day.