Since the program was launched less than two years ago, officers have saved at least 320 people from an overdose death.
Arapahoe House, which treats about 5,000 substance abuse cases a year in the Denver metro area, is scheduled to close January 2.
The proposed safe-injection facility is part of a six bill package to combat the growing opioid crisis in Colorado.
Saturday marks National Prescription Drug Take Back Day.
Denver's library is one of the first to carry Narcan, the brand name for Naloxone, a medication used to reverse an opioid overdose.