Vancouver mayor Gregor Robertson and five of his predecessors called on the federal government today to reconsider its opposition to the Insite safe injection facility.

"Since opening in 2003, Insite has proven -- beyond a doubt -- its worth to our community," wrote the group of mayors in an open letter addressed to the federal government. 

"Insite and its staff of healthcare professionals provide essential, life-saving benefits to vulnerable Canadians. For many, access to Insite is literally a matter of life and death."

At Insite, located in Vancouver's Downtown Eastside, intravenous drug users inject illicit substances such as heroin. The clinic oversees the injections, provides sterile drug paraphernalia and responds to medical emergencies such as drug overdoses.

BC Ministry of Health Services runs the facility in conjunction with the Portland Hotel Community Services Society. 

The Supreme Court of Canada will hear arguments Thursday that will determine the fate of the facility. The court will decide who has jurisdictional authority over the clinic, Ottawa or B.C., and whether closing the facility infringes on any rights.

Stephen Harper's government tried once already to shut it down, but the B.C. Supreme Court and a subsequent B.C. Court of Appeal both said that would be unconstitutional. 

Five previous mayors of Vancouver joined Robertson, including Phillip Owen, who developed the Four Pillars Drug Strategy that led to the creation of Insite. 

"Drug addiction is a health issue, not a criminal issue, and Insite needs to be recognized for what it is: a valuable health service that saves lives," said Owen.

The mayors cited research published in The Lancet, a peer-reviewed medical journal, that confirms the facility's effectiveness. 

Eleven other groups that filed for intervener status will also make arguments tomorrow. The BC Nurses Union is among them. The union issued a press release Monday declaring its support.

"It is simply disgraceful that the federal government continues to try and outlaw this legitimate healthcare service and in the process attempt to make criminals out of nurses who are saving lives and providing quality care to this vulnerable population," said union vice president Janice Buchanan.

Other intervening parties that support Insite include the BC Civil Liberties Association, the Canadian Medical Association and the Dr. Peter AIDS Foundation.

Insite is the first clinic of its kind in North America, and operates under an exemption to the Controlled Drugs and Substances Act.

Tyler Harbottle is completing a practicum at The Tyee.