"Although there was a substantial increase in the number of participants who started smoking crack cocaine, it is unlikely that the facility, which does not allow smoking in the facility, prompted this change. These findings are relevant to a recent review of supervised injection facilities by the European Monitoring Centre on Drugs and Drug Addiction, which highlighted concerns that these facilities could potentially 'encourage increased levels of drug use' and 'make drug use more acceptable and comfortable, thus delaying initiation into treatment.'"

Source

Kerr, Thomas, Jo-Anne Stoltz, Mark Tyndall, Kathy Li, Ruth Zhang, Julio Montaner, Evan Wood, "Impact of a medically supervised safer injection facility on community drug use patterns: a before and after study," British Medical Journal, Vol. 332, Jan. 28, 2006, p. 222.