These centers would be modeled on those operating in Canada and some European countries. They invite visitors to use heroin, fentanyl and other deadly drugs without fear of arrest. The policy is “B.Y.O.D.” — bring your own drugs — but staff members help people abuse drugs by providing needles and stand ready to resuscitate addicts who overdose.

Last year, San Francisco assembled a task force to establish an injection site, and last week the California State Senate passed a bill that would allow San Francisco to operate such sites and grant legal immunity to the drug users who visit them. In May, the mayor of New York City announced a plan to open four injection sites. A Seattle task force approved a similar plan, and city officials have pitched outfitting a van as a mobile injection site. Numerous states, including Colorado, Massachusetts, Vermont and Maine, have explored similar options to help their residents use hard-core drugs.

One obvious problem with injection sites is that they are illegal. It is a federal felony to maintain any location for the purpose of facilitating illicit drug use. Violations are punishable by up to 20 years in prison, hefty fines and forfeiture of the property used in the criminal activity. The law also authorizes the federal government to obtain civil injunctions against violators. Because federal law clearly prohibits injection sites, cities and counties should expect the Department of Justice to meet the opening of any injection site with swift and aggressive action.

Proponents of injection sites say they make drug use safer, but they actually create serious public safety risks. Many people addicted to opioids use illicit fentanyl or one of its analogues, which can be up to 5,000 times more powerful than heroin. Users often have no idea what they are actually buying from criminal drug dealers. Moreover, a bystander or emergency medical worker who comes into contact with such drugs can be gravely harmed.

Additionally, injection sites destroy the surrounding community. When drug users flock to a site, drug dealers follow, bringing with them violence and despair, posing a danger to neighbors and law-abiding visitors. For instance, the area near an injection site in Vancouver, British Columbia, was described by a member of the Redmond, Wash., City Council as “a war zone” with “drug-addled, glassy -eyed people strewn about” and “active drug dealing going on in plain sight.”