A bill that imposes a lengthy list of requirements for health authorities and community agencies to maintain a harm-reduction site could threaten the continued operation of Canada's first safe injection site and endanger lives if it's passed, say advocates.

On Wednesday, the Senate's standing committee on legal and constitutional affairs will hear testimony from medical experts on Bill C-2, the Respect for Communities Act.

The bill not only makes it harder for people to open a harm-reduction site like Vancouver's Insite, it also lays out 26 requirements for existing operators to be granted an exemption under the Controlled Drugs and Substances Act.

Pivot Legal Society argues Bill C-2 is unconstitutional — particularly when a 2011 Supreme Court of Canada decision ruled that supervised injection sites have been proven to save lives — and the federal health minister's refusal to grant an exemption violates drug users' constitutional rights to life-saving medical care .

"There's a bigger problem with the bill than just the criteria," Pivot Legal Society's health and drug policy lawyer Adrienne Smith told The Early Edition's Rick Cluff.

"It changes the whole structure of how these exemptions are given, and they say such an exemption will only be given in very exceptional circumstances, which is really different from what the Supreme Court of Canada said in a landmark decision in just this section of law."

Under Bill C-2, applicants that want an exemption to operate a supervised injection site will have to meet requirements such as obtaining a letter from a local police chief, broad community consultation, support from public health officers and crime statistics.

The federal government has consistently criticized offering drug users legal spaces to consume illegal substances.

Smith says Insite is one of the most studied health facilities in the world, and research has shown that it reduces crime and incidents of diseases such as HIV, and increases referral to treatment in detox facilities.

To hear the full interview with Adrienne Smith, listen to the audio labelled: Bill C-2 could threaten Vancouver's Insite, says advocates