The 80216 zip code, which includes the Denver neighborhoods of Globeville, Elyria and Swansea, ranked as the most polluted zip code in America according to a 2017 study from ATTOM Data Solution. The study examined homes around the country for their risk factors of four different environmental hazards: superfunds, brownfields, polluters or poor air quality. The 80126 zip code has all of them.  

The discovery of gold in the budding territory in 1858 started a wave of mining and smelting companies setting up shop in Colorado’s high country. Then, smelters moved down to Denver to be close to the railroad once it was established. This included the Argo Smelter established in 1879 and the Holden Smelter in 1885 which became part of the Globe Smelter and Refining Company four years later, giving birth to the name of the neighborhood – Globeville. 

“It's not a good sign when your community is named after the smelter that will continue to pollute you for the next 107 years,” said Alex Hernandez, a special collections librarian with Denver Public Library. 

The railroad not only attracted smelters but also other industries including animal rendering plants, slaughterhouses, stockyards and any other type of commerce going in and out of Denver. And with industry came jobs and workers who often found the most affordable living right next to the smelters where arsenic mixed with other chemicals billowed out of smoke stacks for years.  

“The big issue was actually black smoke. So there was black smoke everywhere inside central Denver. So I can't even imagine what it would have been like living nearby to multiple smelters because they were just constantly letting gasses into the air,” said Hernandez. 

Still, the community remained tight-knit until the Eisenhower administration introduced the U.S. Interstate Highway System in 1956. While building nationwide highways, planners often cut right through cities and communities of color to build the highways,which included the 80216 zip code. Workers completed Interstate 25 in 1958 and Interstate 70 in 1964, which cut apart the neighborhoods and added more pollution. 

“The biggest cause of air pollution from my experience with my research in Denver is the traffic. We have traffic related air pollution levels that increasingly affect your health as you move closer to the roadway,” said Shelly Miller, a University of Colorado Boulder air pollution engineer. 

With more than a century of pollution to deal with now residents are working to combat it and make their voices heard. 

You can watch "Colorado Experience | The Most Polluted Zip Code" Part 1 and Part 2 below. 

Thank you to Alex Hernandez, a special collections librarian with Denver Public Library who provided information for the timeline below. You can read more about the Globeville Neighborhood History here.