In San Francisco, the drug union received its first grant in 2009, Mr. Jackson said, and got more help in December 2010 from the city’s Hepatitis C Task Force, which advocated for a pilot “supervised injection facility” for intravenous drug users because they often contract hepatitis by using dirty needles. No such facility exists in the United States — a so-called safe injection site in Vancouver, British Columbia, has been considered a success there — and it has become a central goal of the San Francisco union.

Advocates for such a site say it would not only help prevent new hepatitis and AIDS infections but could also provide a contact point for other health services, including rehabilitation, for addicts who are often loath to seek help.

And in one of the more liberal cities in the nation, the idea of a safe injection site has won some support, including from several mayoral candidates last fall like John Avalos, a leader of the progressive bloc of the city’s all-Democratic Board of Supervisors. Laura Thomas, the interim California director for the Drug Policy Alliance, a drug reform organization in New York that helps finance the union, said that San Francisco had a history of “compassionate response” to drug users, and that an injection site was not so far-fetched.

“I have a small bet with one of my co-workers as to who is going to get there first, New York or San Francisco,” Ms. Thomas said. “Certainly I want San Francisco to be the first.”

Still, such a plan faces political and economic challenges, said Alice Gleghorn, the county alcohol and drug administrator, who oversees the city’s drug abuse prevention and treatment programs and opposes the idea of an injection site. “We do have trouble even in San Francisco finding locations for new substance abuse programs,” Ms. Gleghorn said. “Can you imagine what kind of Nimbyism would come about if someone were to try to put a safe injection site somewhere?”

Mayor Ed Lee also opposes the idea, saying that the city has ample tools for attacking the problem of intravenous drug use, including syringe exchanges, said Christine Falvey, a spokeswoman for the mayor.

Mr. Jackson, 56, admits to using methamphetamine — his drug of choice, one he said was “love at first sight” — despite a personal history that would probably argue against it.