Denver Police Encryption: When the Mile High City Went Dark

What Happened in Denver

Denver Police Department had operated with open radio communications for decades. Local news stations monitored police channels around the clock. Parents kept scanners during school emergencies. Neighborhood watch groups tracked nearby incidents. Amateur radio enthusiasts and scanner hobbyists formed an informal public safety network.

In 2022, that ended. Denver PD switched to P25 AES-256 encryption, making all police radio traffic inaccessible to anyone without department-issued equipment. Aurora, Lakewood, Westminster, and other suburban departments followed within months, creating a coordinated regional blackout.

The decision came despite Colorado passing HB21-1250 in 2021—the nation's first statewide law requiring agencies with encrypted systems to create media access policies. The law was meant to preserve transparency. Instead, Denver and its neighbors implemented encryption anyway, with media access policies that exist largely on paper.

The Marshall Fire: When Information Mattered Most

On December 30, 2021, the Marshall Fire tore through Boulder County, becoming Colorado's most destructive wildfire in history. Wind gusts up to 100 mph drove flames across grasslands into suburban neighborhoods. Over 1,000 homes were destroyed. More than 35,000 people evacuated—many with only minutes of warning.

During the chaos, residents scrambled for information. Official channels were overwhelmed. Evacuation zone boundaries changed rapidly. Families separated in the confusion searched desperately for updates.

While the Marshall Fire primarily affected Boulder County (where some agencies remained unencrypted), it exposed the regional coordination problems that encryption creates. Mutual aid between encrypted and unencrypted agencies became complicated. Journalists covering the fire couldn't monitor Denver-area resources being deployed.

The fire was a preview of what encryption would mean for future disasters—and Denver pushed forward with encryption anyway, completing it just months later.

Impact on Local Journalism

Denver's local news stations—KUSA 9News, KCNC CBS4, KDVR Fox31, and others—built decades of breaking news coverage on scanner monitoring. Reporters could dispatch immediately to developing situations. Photographers knew where to position themselves. Newsrooms could verify reports before broadcasting.

Post-encryption, that workflow is broken:

Colorado's HB21-1250 was supposed to address this by requiring media access policies. In practice, the policies have proven difficult to implement. As of 2026, no major Denver news organization has real-time, unfiltered access to police radio despite the law's requirements.

The Unencrypted Comparison: Boulder, Fort Collins, and Beyond

While Denver went dark, several Colorado communities maintained transparency. The contrast is instructive:

Boulder Police Department has operated with open communications for decades without incident. Fort Collins—a major university town—maintains transparency without documented harm. If open radio were truly dangerous, these communities would have evidence. They don't.

Denver's choice to encrypt wasn't driven by evidence of harm from transparency. It was a policy decision to prioritize institutional control over public access.

Colorado's Failed Promise: HB21-1250

Colorado made history in 2021 by passing HB21-1250, the first statewide law requiring police departments with encrypted radio to establish media access policies. The bill was championed by journalists, civil liberties groups, and transparency advocates.

The law requires:

• Written policies for credentialed media access to encrypted communications
• A process for journalists to apply for access
• Reasonable timeframes for reviewing applications

The reality has been different. Agencies have created policies, but implementation is inconsistent. Access agreements are rare. Journalists report bureaucratic hurdles and delays. The law lacks meaningful enforcement mechanisms.

Denver's encryption went forward knowing the law existed. The department created a media access policy—and then made it difficult to actually use. The legislative victory hasn't translated to practical transparency.

What You Can Do

If you live in the Denver metro area, encryption is already in place—but the fight isn't over:

• Contact your city council: Demand they pressure police departments to implement meaningful media access under HB21-1250
• Support local journalism: News organizations need resources to pursue access agreements and legal challenges
• Attend public meetings: When police budgets are discussed, raise transparency concerns
• Document the impact: If you've experienced harm from lack of information during an emergency, share your story
• Monitor neighboring communities: Boulder, Fort Collins, and Greeley remain accessible—support their continued transparency
• Push for enforcement: HB21-1250 exists but lacks teeth. Advocate for amendments that create real accountability