Commerce City

Commerce City incorporated on December 12, 1952, combining several small settlements, Adams City, Derby, Irondale and Rose Hill, partly as a defensive move to keep Denver from annexing the area. It became a home-rule city in 1962. The economy here was built on oil refining. The Continental Oil Company, later Conoco, built a refinery around 1930, and by the 1950s the city had roughly six refineries running alongside grain elevators and other manufacturing. That refining identity is still true today: Suncor Energy operates what’s been called Colorado’s largest refinery here, historically supplying around 15 percent of the state’s gasoline.

From chemical weapons plant to wildlife refuge

The most important thing to understand about Commerce City’s history is the Rocky Mountain Arsenal. The U.S. Army built it starting in 1942 on about 20,000 acres, chosen for its inland location and rail access. From 1942 to 1969 it manufactured chemical weapons, mustard gas, lewisite, chlorine gas, napalm, and later sarin nerve agent, along with conventional munitions. The Army also leased parts of the site to private companies, including Shell Oil from 1952 to 1982, for pesticide manufacturing. Decades of waste disposal in unlined basins contaminated the soil and groundwater, and the site landed on the EPA’s Superfund list in 1987. Cleanup ran from roughly 1985 to 2010 and cost more than $260 million combined. Congress designated the site a National Wildlife Refuge in 1992, and it’s now about 15,000 acres, the largest urban wildlife refuge in the country, home to more than 330 species and a reintroduced bison herd. State and federal health surveillance hasn’t found elevated cancer or birth-defect rates in the surrounding communities, and public trail areas are actively monitored. Parts of the site remain permanently restricted from residential use, well water, and agriculture. It’s a genuinely remarkable turnaround, and it’s also a real Superfund site with real history, and I think you should know both halves of that story.

The active refinery next door

Suncor’s refinery, which the company has operated since acquiring it in the mid-2000s, has drawn serious, recent regulatory scrutiny. A 2023 EPA review found it has more unplanned pollution releases than comparable U.S. refineries, and an inspection that October found cracked, leaking storage tanks. In February 2024, Suncor agreed to a $10.5 million settlement, the largest air-pollution penalty in Colorado history, for violations from 2019 through 2021. In July 2024, the EPA and Colorado’s health department issued a joint notice alleging ongoing Clean Air Act violations, including benzene emissions, the first EPA-led enforcement action against the facility. The refinery sits in a majority-Latino part of the city, and this is genuinely an active, unresolved situation as of this writing, not old history. I’m not going to tell you it’s unsafe to live in Commerce City. Tens of thousands of people do, and the city has real, fast-growing family neighborhoods. I am going to tell you plainly that if you’re considering a home near the refinery specifically, that’s worth factoring in, and I’ll help you understand exactly how close is close.