Colorado continues to face an increase in overdose deaths while other states have seen a downturn.

Illicitly manufactured fentanyl, a potent opioid, emerged in the Colorado drug market around 2018. That was nearly five years after it began tormenting people who use street drugs in Northeastern states.

By 2019, fentanyl replaced other drugs as the driving force behind opioid overdoses in Colorado, and it has held its grip ever since.

But while overdose deaths in the U.S. are currently experiencing a historic decline of almost 14%, Colorado is one of eight states where rates are not dropping. In fact, Colorado has had an increase of nearly 12% in overdose deaths since April 2025.

Overdoses are top of mind for many everyday Coloradans, healthcare professionals, elected officials and public health experts like me.

Proposition 132 attempts to address these concerns by stiffening legal penalties. A conservative policy organization called Advance Colorado collected the signatures to get the initiative on the November ballot.

The proposed change to Colorado law would make possession of any amount of fentanyl a felony, require a mandatory minimum eight-year prison sentence for distribution of any quantity of fentanyl, and eliminate some existing opportunities for reduced penalties.

Before Coloradans head to the polls, it is worth examining the state’s overdose trends and considering whether Proposition 132 is likely to solve the problem.

A 2022 law already increased penalties

Let’s start by looking at Colorado’s past attempts to stop drug overdoses through legislation. In recent years, the state has pursued some public health interventions but has leaned heavily on increasing criminal penalties for using and possessing fentanyl.

The 2022 Fentanyl Accountability and Prevention Act (HB22-1326), for instance, represented a major expansion of criminal penalties.

This law rolled back a 2019 law that had decriminalized small amounts of drugs. Specifically, HB22-1326 made the knowing possession of more than 1 gram and up to 4 grams of a substance containing fentanyl a Level 4 drug felony punishable by up to 180 days in jail and two years of probation.

Unlike Proposition 132, the 2022 fentanyl act directed funding for the distribution of naloxone, an overdose reversal medication, and fentanyl test strips that help people identify fentanyl in their drugs before using them. Both naloxone and fentanyl test strips decrease the risk of fatal overdose.

The law did not direct funding toward evidence-based treatments such as methadone or buprenorphine for opioid use disorder.

Supporters argued that the legislation was necessary to prevent overdose deaths and get people treatment.

I led a research team that included addiction treatment providers and substance use–focused epidemiologists to study the effects of HB22-1326. Although more people were arrested and faced the tougher penalties, we found no increase in people beginning or staying on buprenorphine. We also found that fewer people were starting and staying on methadone following the implementation of the law.

Importantly, we found that the law did not change the trajectory of overdose deaths compared to what was expected. Taken together, we found no substantial evidence that increasing criminal penalties, even with some increased funding for naloxone and overdose prevention, “saved lives” as proponents had hoped.

Colorado is already uniquely punitive toward people who use illicit drugs, with some of the harshest penalties for drug possession and distribution in the U.S. Colorado’s public health response has developed alongside, not in place of, a substantial criminal-legal response.

What decreases overdose deaths?

Even with efforts to provide additional access to harm-reduction protections, escalating criminal penalties have not produced the treatment gains or decreases in overdose deaths in Colorado that proponents promised.

So, let’s look at a place in the state where overdose deaths are actually falling to see what is being done differently there.

Larimer County, home of Colorado State University and part of Rocky Mountain National Park, offers the clearest contrast to the rest of the state. Accidental overdose deaths have declined year after year since 2022, down nearly 42% from 2021.

What’s going on in Larimer County?

For one, the Larimer County Jail is one of less than half of the Colorado county jails that offers a comprehensive treatment program that includes medications for opioid use disorder.

The sheriff’s office, in collaboration with several community-based organizations, has also flooded the community with naloxone through the Reversal Project. Furthermore, using opioid abatement funds, the county has expanded youth and family support services, co-responder units and other harm-reduction services. The county has also steadily increased the number of people on buprenorphine.

No single intervention can be credited with Larimer County’s decline in accidental overdoes deaths. Criminal enforcement remains one component of the county’s response. Yet, what stands out is its emphasis on evidence-based interventions with an emphasis on expanding treatment access and harm-reduction services that save lives and give people the stability and opportunity to build healthier lives.

A polysubstance problem

In addition, Proposition 132 has a major flaw. It targets one drug: fentanyl. But the available data suggests most people take fentanyl together with stimulants such as methamphetamine. Both drugs can be fatal.

Between 2020 and 2024, nearly 40% of overdose deaths in Colorado involved both opioids and stimulants. National figures follow a similar pattern. Nationally, 43% of overdose deaths in 2024 involved both opioids and stimulants.

Targeting one substance, as Proposition 132 does, ignores the fact that the state has a true “polysubstance” epidemic and will end up making people who unknowingly possess fentanyl susceptible to harsher penalties set forth by Proposition 132.

Since Colorado increased fentanyl penalties in 2022, the promised treatment gains examined in our research have not materialized. The state’s number of overdoses has continued to climb.

Those facts do not mean that criminal penalties alone caused Colorado’s worsening trend. But they do raise an important question as voters consider Proposition 132: What evidence suggests that increasing those penalties further will address the rise in overdose deaths?