"States have clear legal authority to authorize SIFs, just as they can legalize the cultivation, distribution, and possession of marijuana for medical purposes.76 State authorization could make a SIF legal under state law and prevent state law enforcement officials from taking action against it. It is equally clear, however, that state authorization cannot nullify federal drug laws, and so does not protect a SIF against being shut down by federal law enforcement agencies through raids, arrests, or other legal proceedings.

"There are at least 2 sections of the federal Controlled Substances Act that could be interpreted to bar a SIF. Section 844 prohibits drug possession and so is violated by every client who appears at the clinic with drugs.77 Although federal law enforcement officials rarely if ever target simple possession by individuals,78 the law would allow them to do so if they wished to interfere with the operation of a SIF.

"A SIF authorized at the state or local level could also be deemed to violate Section 856, known as the Crack House Statute. This law makes it illegal to 'knowingly open or maintain . . . [or] manage or control any place . . . for the purpose of unlawfully . . . using a controlled substance.'"

Source

Leo Beletsky, Corey S. Davis, Evan Anderson, and Scott Burris, "The Law (and Politics) of Safe Injection Facilities in the United States," American Journal of Public Health, (Vol. 98, No. 2) February 2008, p. 234.