The country’s first supervised-injection site will open next week in South Philadelphia, the site’s operators said Tuesday within hours of a federal judge’s entering a final ruling that the proposed facility would not violate federal law.

The organizers behind Safehouse, the nonprofit formed to open the site, were expected to announce details of their plan at a news conference Wednesday.

They would not comment on the exact location of the site Tuesday evening, but sources familiar with the decision confirmed that the site would operate out of Constitution Health Plaza, 1930 S. Broad St., just steps from Passyunk Avenue. The site would have a separate entrance for its clients.

Locator map of Safehouse's first supervised-injection site in Philadelphia, on South Broad and McKean Streets.

The organization plans to open a second site elsewhere in the city shortly after the South Philadelphia opening. The city has also issued a public-safety plan for the area outside a site, and Safehouse has been training volunteer escorts, like those that abortion providers have used for years to protect women.

The opening is the culmination of a two-year battle to open a place where people in addiction can use drugs under medical supervision, be revived if they overdose, and access treatment.

But even though Safehouse’s backers plan to be welcoming clients next week, the legal battle over the site is not over.

U.S. Attorney William M. McSwain on Tuesday said he intends to appeal U.S. District Judge Gerald A. McHugh’s ruling. And some neighborhood groups in South Philadelphia are already raising alarm.

McSwain, who maintains a supervised injection site would promote drug use and lead to a rise in crime in the surrounding area, has threatened to use “all enforcement tools” at his disposal, including arrests, drug seizures, and criminal forfeitures, to stop any site that opens before the appeals process is complete.

“We believe that Safehouse’s proposed activity threatens to institutionalize the scourge of illegal drug use — and all the problems that come with it — in Philadelphia neighborhoods,” he said in a statement. “In light of these concerns, Safehouse should act prudently and not rush to open while the appeal is pending. But if it does rush forward, my office will evaluate all options available under the law.”

Safehouse organizers have said that time is of the essence, and that the nonprofit is designed to save lives amid an unprecedented overdose crisis that has killed nearly 3,500 Philadelphians in the last three years.

“Philadelphia, like the nation, is in a crisis,” said Ronda Goldfein, Safehouse vice president. “And we have the opportunity to address that crisis; we owe it to Philadelphia to do that.”

Much of the city’s attention — and conversation around a supervised-injection site — has been focused on Kensington, the neighborhood at the center of the city’s opioid crisis, where people openly sell and use drugs, encampments of people in addiction line the streets and more people fatally overdose than anywhere else in the city.

And while the crisis is less visible in South Philadelphia, where the Safehouse facility will launch, the area’s overdose rate is staggering on its own: About one person a week dies in the zip codes that the site will serve.

Goldfein hopes that neighbors won’t notice much of a change in day-to-day life around the site, but said the nonprofit plans a community meeting to address concerns on March 10, about a week after the facility is expected to open.

“This is not pop-up tents and Narcan. This is a dedicated connection” to services for people in addiction, Goldfein said, in a neighborhood where those resources are few and far between.

The nonprofit is also looking to work with South Philadelphia neighbors who support the site, like Kelli Murray-Garant, a Pennsport resident who is in recovery and works on a van that distributes medication-assisted treatment in Kensington. She said people in addiction can hold down jobs and find housing — as she did during her heroin addiction. But the shame and stigma that keeps them inside is also killing them, she said.

Two years ago, Murray-Garant relapsed and overdosed in the bathroom of the home she shares with her husband, who is also in recovery. She was afraid to tell him that she was using again, she said. She was blue in the face, she said, by the time he found her on the bathroom floor.

After surviving her overdose, Murray-Garant entered recovery, began volunteering with people in addiction, and eventually landed her current job in Kensington. She said she wanted people in her neighborhood to know that a supervised injection site “is getting people help — not enabling.”

“If a supervised injection site had opened when I relapsed,” she said, “I would have gone there. I might not have used in my bathroom — because that’s where most people in South Philadelphia use.”

Tuesday’s court order did not come as a surprise. It echoed a preliminary ruling McHugh issued after days of hearings last fall in which he found the overdose prevention facility Safehouse was proposing did not violate a federal law passed in the 1980s to target drug dens at the height of the crack-cocaine epidemic.

The decision was the first in the United States to address the legality of a site where people in addiction could use their own illegal drugs under medical supervision, access treatment, and be revived if they overdosed.

McSwain, who personally argued the case before McHugh, said in his statement Tuesday that he “respectfully disagreed” with the ruling.

“What Safehouse proposes is a radical experiment that would invite thousands of people onto its property for the purpose of injecting illegal drugs,” he said. “In our view, this would plainly violate the law, and we look forward to presenting our case to the U.S. Court of Appeals for the Third Circuit.”

Supporters say the primary reason for the sites is to protect the public’s health and help keep people alive until they are ready to go into recovery. As such, they maintain, they should be legal as they are in Canada and some European countries, where they have operated for decades.

Philadelphia officials have said that they would sanction — but not fund — the opening of a site.

“The bottom line is that overdose prevention sites — which exist in more than 100 cities around the world — offer compassion for fellow human beings,” Mayor Jim Kenney said in a statement Tuesday. “Our job as a city is to support efforts to alleviate suffering and to save lives.”

Ronda Goldfein of Safehouse is the wife of David Lee Preston, an editor at The Inquirer. He is not involved in coverage of this story.