The federal government has permitted the province to conduct this trial without any criminal penalties.

https://news.gov.bc.ca/releases/2023MMHA0005-000106

>Health Canada granted the Province of B.C. a subsection 56(1) exemption under the Controlled Drugs and Substances Act to decriminalize people who use drugs. Beginning Jan. 31, 2023, until Jan. 31, 2026, adults (18 and older) in B.C. will not be subject to criminal charges if they possess a small amount of certain illegal drugs for personal use.

Here's the statement from the federal associate minister of Health

https://www.canada.ca/en/health-canada/news/2023/01/statement-from-the-minister-of-mental-health-and-addictions-and-associate-minister-of-health-on-the-implementation-of-the-subsection-561-exemption-.html

>On May 31, 2022, I announced the granting of a time-limited exemption under the Controlled Drugs and Substances Act for adults in the province of B.C. As of tomorrow, January 31, 2023, until January 31, 2026, adults aged 18 years or older within B.C will not be subject to criminal charges for the possession of small amounts of opioids, cocaine, methamphetamine, and MDMA for personal use.