Boulder County Public Health warned community members that dangerous fentanyl is circulating in the county's illicit drug supply. The warning comes as overdose deaths involving fentanyl have increased significantly.
According to the Colorado Department of Public Health and Environment, fentanyl poisoning caused 35 deaths in Boulder County in 2025, up from 24 in 2024. Statewide, deaths rose to 980 from 760 over the same period.
Fentanyl is a synthetic opioid up to 50 times more potent than heroin and 100 times more potent than morphine, and is a leading cause of accidental drug overdose deaths in the county and nationwide.
Boulder County Public Health urged residents to take preventive steps including carrying naloxone, learning to use it properly, testing drugs with fentanyl test strips, and avoiding drug use alone. The agency also advised people to assume any pill or powder obtained outside a pharmacy may contain fentanyl and to call 911 immediately if an overdose is suspected. Colorado's Good Samaritan Law protects those who call for help during an overdose if they remain on the scene.
Naloxone, also known as Narcan, can reverse opioid overdoses including those involving fentanyl, though multiple doses may be required. It is available without a prescription at many local pharmacies and is covered by most insurance plans.
"Fentanyl can be manufactured in many different colors and consistencies and may be mixed with other dangerous drugs," said Dr. Georgia Babatsikos, harm reduction program manager at Boulder County Public Health.