Philadelphia, San Francisco, and other U.S. cities are considering opening sites where people addicted to drugs can inject with clean needles under supervision.

Philadelphia is pushing to become the first U.S. city to legalize supervised injection sites for people addicted to drugs.

This is part of the city’s effort to curb the rise in drug overdose deaths.

Last year, more than 1,200 people in the city died due to drug overdose, reports the Philadelphia Inquirer — a jump from the previous year and the highest rate for any city in the nation.

Opioids were involved in more than 8 out of 10 overdoses in Philadelphia.

The supervised injection sites would provide a location for people with a drug addiction to inject drugs under supervision. It would also give them access to sterile injection equipment and the anti-overdose medication naloxone.

Sites would also refer people to treatment centers, social services clinics, and other health facilities.

These are also known as “safe injection sites,” although some public health officials avoid using the term “safe” because they say illicit drug use is dangerous no matter where you do it.

Although these sites remain controversial, they’re becoming more attractive as the opioid epidemic continues unabated.

In 2016, more than 42,000 Americans died of an opioid overdose and more than 2 million had an opioid use disorder, reports the U.S. Department of Health and Human Services.

Philadelphia will not operate or pay for the proposed sites in the city. Instead, it will encourage private organizations to take on the project.

This would avoid the need for city council approval. That doesn’t mean, though, that the sites won’t face challenges.

Using drugs such as cocaine, heroin, and other illicit opioids remains a federal crime. So the sites would depend on the city not using its police force to arrest people who inject drugs at these locations.

The Inquirerreports that some politicians have called on Pennsylvania Gov. Tom Wolf to block the city, although he has not indicated that he would stand in the city’s way.

The governor also recently declared the heroin and opioid epidemic a statewide disaster emergency.

San Francisco is expected to open two supervised injection sites in July. Other cities — including New York City, Ithaca, and Denver — are considering opening their own sites.

An unauthorized, and illegal, safe injection site has been operating at an undisclosed U.S. location since 2014.

With no legal supervised injection sites in the United States, Philadelphia and other cities have turned to cities in Canada, Australia, and Europe for advice. These countries all have sites that have operated for the last few decades.

One of these is Vancouver’s Insite, which opened in 2003 and is North America’s first legal supervised injection site.

Since Insite opened, more than 3.6 million people have injected illegal drugs under supervision there.

Tiffany Akins, the communications leader for Vancouver Coastal Health (VCH), which operates the site, told Healthline that in 2017 heroin accounted for over 64 percent of the substances reported used at the site.

Many studies have tried to determine how much of an impact supervised injection sites have on people who are addicted to drugs and on the neighborhoods where they are located.

Last year a group of researchers reviewed 47 previous studies. The study was published in Current HIV/AIDS Reports.

The majority of the studies were conducted in Vancouver, Canada, with the rest in Australia or Europe. Although results varied among sites, some benefits emerged.

Researchers found that after Insite opened, overdose deaths in the immediate vicinity of the site dropped by 35 percent. The rest of the city saw a 9 percent decline in overdose deaths.

According to the Insite website, more than 6,000 overdoses have been prevented at the site since it opened, without any deaths. During that time, more than 48,000 people received HIV testing, foot or wound care, contraception, or other clinical services while at the site.

The review also found that regular users of the supervised injection site in Vancouver were 70 percent less likely to report borrowing or lending used syringes, compared to people who didn’t visit the site regularly.

Using nonsterile needles to inject drugs increases the risk of contracting infectious diseases such as hepatitis or HIV.

More than half of the 17,000 new hepatitis C infections in the United States in 2010 were among injection drug users, according to the National Institute on Drug Abuse.

Four studies in the review showed that people who used the supervised injection site were more likely to enter a detox program or addiction treatment.

VCH also operates an adjoining detox treatment facility called Onsite. Akins said that during the past year, 443 people visiting Insite were referred to this facility. They stayed an average of 11 days, with 179 people no longer needing detox services.

One barrier to opening a supervised injection site is concern by people living in the neighborhood about an increase in drug users visiting the area.

After Vancouver opened a supervised injection site, though, the city saw a drop in people injecting drugs in public and in publicly discarded syringes, according to the review study.

As for cost, supervised injection sites have the potential to save cities and countries money by preventing hepatitis or HIV infections. The review study found that estimates of these savings range from $200,000 to $1.8 million per year, in Canadian dollars.

In spite of the public health benefits of setting up a supervised injection site, the path forward is not easy — even in Canada, where Health Canada reports that there are currently almost 30 open sites.

When Ottawa, Canada, started exploring the idea of opening a site in 2016, the mayor, police chief, and chair of the city’s board of health were all opposed, reports the CBC.

Despite the opposition, local health and social services groups pushed forward with their applications. The city now has four operating sites.

And like Vancouver, Ottawa hasn’t seen an increase in drug crime near the sites.

As more cities show that supervised injection sites can be successful, other cities may be more likely to get on board.

The CBC reports that the mayor of Toronto visited an unsanctioned site in Ottawa last year. Toronto now has three open sites and two more undergoing renovations, according to Health Canada.

If that can happen in Canada, then successful sites in Philadelphia or San Francisco may convince other cities to follow in their footsteps.