9 Hazardous Sites Near Denver, CO


Each time I visit Denver, CO, I am in awe of the majestic Rocky Mountains. With the unrivaled natural beauty that surrounds the city, it just doesn’t seem possible Denver would contain any hazardous sites.

So, does the Denver area contain any hazardous sites? Well, unfortunately, as with most populated places on the planet, there are some potentially dangerous sites in Denver. In fact, there are nine Superfund sites within a 25-mile radius of the Mile High City, including:

  • Denver Radium Site
  • Vasquez Boulevard & I-70
  • Broderick Wood Products
  • Chemical Sales Co.
  • Rocky Mountain Arsenal
  • Rocky Flats Plant
  • Lowery Landfill
  • Air Force Plant PJKS
  • Marshall Landfill

Superfund sites are contaminated areas identified by the EPA as candidates for cleanup due to the significant threats they pose to human health and the environment. There are currently over 1,300 Superfund sites nationwide, and no two are exactly alike.

Superfund Sites Within 25 Miles of Denver

1. Denver Radium Site

The Denver Radium site, which consists of more than 65 properties, is located in Denver, CO along the South Plate River Valley.

What happened at the Denver Radium site?

In the early 1900s, radium was a hot commodity. It was used in a host of products, including fertilizers, timepieces, and cosmetics. Believe it or not, radium was even touted as a cure for cancer.

After the National Radium Institute was established in Denver in 1913, the city became a radium boom town. During this period, a number of Denver-based companies manufactured and sold products containing radium. The radium they used in their products was extracted from Carnotite Ores sourced from the Colorado Plateau.

Radium processing activities that took place in Denver into the 1920s contaminated the Denver Radium site with radioactive residues.

What contaminants were released at the Denver Radium site?

The EPA identified unacceptable levels of more than 12 harmful contaminants at the Denver Radium site, including:

  • Radium
  • Uranium
  • Thorium
  • Lead
  • Arsenic

What is the status of the cleanup effort at the Denver Radium site?

Cleanup activities at the Denver Radium site were completed on 09/27/2006. However, the EPA is still working at the site to ensure the continued protection of human health and the environment. 

2. Vasquez Boulevard & I-70

The Vasquez Boulevard & I-70 site is in northeastern Denver. It contains two industrial areas as well as residential properties in the following neighborhoods:

  • Cole
  • Clayton
  • Curtis Park
  • Elyria-Swansea
  • Globeville

What happened at the Vasquez Boulevard & I-70 site?

Beginning in the late 1800s, Denver became a smelting hub for mining operations throughout the region. Smelting is a process whereby heat is applied to ore (i.e., rock or sediment) to extract metals like copper, gold, lead, silver, and zinc.

Omaha & Grant and Argo operated smelting plants at Vasquez Boulevard & I-70. These operations contaminated area soils with heavy metals.

What contaminants were released at the Vasquez Boulevard & I-70 site?

The EPA found dangerous levels of Arsenic and Lead in the soil at the Vasquez Boulevard & I-70 site. 

What is the status of the cleanup effort at the Vasquez Boulevard & I-70 site?

Initially, the Vasquez Boulevard & I-70 site consisted of three areas or Operable Units (OUs) as the EPA calls them:

  • OU1 – Residential Soils
  • OU2 – Omaha & Grant Smelter
  • OU3 – Argo Smelter

Contaminated soils at residential properties have been remediated, and as of 09/20/2019, cleanup activities at OU1 are considered complete. Cleanup efforts at the Omaha & Grant Smelter and the Argo Smelter, however, are still ongoing.

3. Broderick Wood Products

The Broderick Wood Products site is a 64-acre area located at 5600 Huron Street in Denver, CO.

What happened at the Broderick Wood Products site?

From 1947 to 1982, Broderick Wood Products operated a wood treatment facility on site. The company used creosote and pentachlorophenol (PCP) to treat a variety of wood products, including fence posts, railroad ties, and power poles. These activities contaminated soil and groundwater with hazardous chemicals.

What contaminants were released at the Broderick Wood Products site?

The EPA identified unacceptable levels of more than 30 harmful contaminants at the Broderick Wood Products site, including:

  • Pentachlorophenol (PCP)
  • Cadmium
  • Arsenic
  • Benzene
  • Lead
  • Naphthalene
  • Toluene
  • Xylene
  • Anthracene

What is the status of the cleanup effort at the Broderick Wood Products site?

Cleanup activities at the Broderick Wood Products site were completed on 09/30/1996. However, the EPA is still working at the site to ensure the continued protection of human health and the environment.

4. Chemical Sales Co.

The Chemical Sales Co. site is a five-square-mile area located at 4661 Monaco Street in Denver, CO.

What happened at the Chemical Sales Co. site?

The Chemical Sales Co. site was used primarily for storage and repackaging of bulk chemicals from rail cars and drums. Activities at the site contaminated groundwater in the South Adams County Water Supply District with volatile organic compounds (VOCs).

What contaminants were released at the Chemical Sales Co. site?

The EPA identified unacceptable levels of more than ten harmful contaminants at the Chemical Sales Co. site, including:

  • Benzene
  • Vinyl Chloride
  • Carbon Tetrachloride
  • Tetrachloroethylene (PERC)
  • Trichloroethylene (TCE)

What is the status of the cleanup effort at the Chemical Sales Co. site?

Cleanup activities at the Chemical Sales Co. site were completed on 03/27/2000. However, the EPA is still working at the site to ensure the continued protection of human health and the environment.

5. Rocky Mountain Arsenal

The Rocky Mountain Arsenal site is a 27-square-mile area located 10 miles northeast of the city of Denver.

What happened at the Rocky Mountain Arsenal?

The Rocky Mountain Arsenal was established in 1942. The U.S. Army used the site to produce munitions and chemical weapons like mustard gas through the early 1980s.

From 1946 until 1982, some site facilities were leased to private companies who produced pesticides on site.

Over time, actions by the U.S. Army and private lessees contaminated the Rocky Mountain Arsenal site.

What contaminants were released at the Rocky Mountain Arsenal?

The EPA found unacceptable levels of numerous harmful contaminants at the Rocky Mountain Arsenal site, including:

  • Arsenic
  • Benzene
  • Chloroform
  • Lead
  • Mercury
  • Pesticides

What is the status of the cleanup effort at the Rocky Mountain Arsenal?

Although a portion of the Rocky Mountain Arsenal is managed as a wildlife refuge by the U.S. Fish & Wildlife Service, cleanup activities are still ongoing at the site.

6. Rocky Flats Plant

The Rocky Flats Plant site is a 6,240-acre area just off Highway 93 between Golden and Boulder.

What happened at the Rocky Flats Plant?

The Rocky Flats Plant played an integral role in the U.S. nuclear weapons program. It was used to manufacture trigger mechanisms for nuclear weapons from 1952 to 1989.

Manufacturing activities, accidental spills and fires, and short-sighted waste management practices contaminated the Rocky Flats Plant site with radioactive substances and other hazardous materials. 

What contaminants were released at the Rocky Flats Plant?

The EPA detected unacceptable levels of several harmful contaminants at the Rocky Flats Plant site, including:

  • Plutonium-239
  • Plutonium-240
  • Americium-241
  • Arsenic

What is the status of the cleanup effort at the Rocky Flats Plant?

Cleanup activities at the Rocky Flats Plant were completed on 09/29/2006. However, the EPA is still working at the site to ensure the continued protection of human health and the environment.

7. Lowry Landfill

The 507-acre Lowry Landfill site is east of Aurora, CO, in unincorporated Arapahoe County.

What happened at the Lowry Landfill?

The Lowry Landfill was in operation from the mid-1960s until 1990. During that time, the site accepted various wastes, including sewage, asbestos, and an estimated 138 million gallons of industrial wastes.

Landfilling operations contaminated the Lowry Landfill site with hazardous chemicals.

What contaminants were released at the Lowry Landfill?

The EPA identified unacceptable levels of numerous harmful contaminants at the Lowry Landfill site, including:

  • Chloroform
  • Cyanide
  • Lead
  • Mercury
  • Radioactive Substances

What is the status of the cleanup effort at the Lowry Landfill?

Cleanup activities at the Lowry Landfill were completed on 09/28/2006. However, the EPA is still working at the site to ensure the continued protection of human health and the environment.

8. Air Force Plant PJKS

The Air Force Plant PJKS (Peter J. Kiewit and Sons) site is a 464-acre area located at 12275 South Highway 75 in Littleton, CO.

What happened at Air Force Plant PJKS?

The Air Force Plant PJKS is owned and operated by Lockheed Martin Astronautics Operation. The company used the site to test Titan Rockets and develop and manufacture space and defense systems.

These activities contaminated soil and groundwater at the Air Force Plant PJKS with hazardous chemicals.

What contaminants were released at Air Force Plant PJKS?

The EPA identified unacceptable levels of over five harmful contaminants at the Air Force Plant PJKS site, including:

  • Trichloroethene
  • Polychlorinated Biphenyls (PCBs)
  • Vinyl Chloride

What is the status of the cleanup effort at Air Force Plant PJKS?

Cleanup activities at Air Force Plant PJKS were completed on 02/24/2014. However, the EPA is still working at the site to ensure the continued protection of human health and the environment.

9. Marshall Landfill

The Marshall Landfill site consists of two adjacent landfills located at 1600 South 66th Street in Boulder, CO. Together, the landfills cover an area of 160 acres.

What happened at the Marshall Landfill?

The Marshall Landfill site is made up of two 80-acre landfills — the Marshall Landfill to the north and the Boulder Landfill to the south.

Marshall Landfill, which operated from 1965 until 1974, accepted solid waste for composting, municipal waste, sewage sludge, and many unknown but potentially hazardous wastes. The Boulder Landfill replaced the Marshall Landfill in 1974 and was utilized by Boulder County until it was closed in 1992.

Landfilling operations contaminated surface water and groundwater at the Marshall Landfill site.

What contaminants were released at the Marshall Landfill?

The EPA found unacceptable levels of eight harmful contaminants at the Marshall Landfill site, including:

  • Benzene
  • Cadmium
  • Chromium
  • Lead
  • Mercury
  • Phenol

What is the status of the cleanup effort at the Marshall Landfill?

Cleanup activities at the Marshall Landfill were completed on 08/25/1993. However, the EPA is still working at the site to ensure the continued protection of human health and the environment.

Are There Any Superfund Sites Near Your Home?

Colorado’s residential disclosure laws require sellers to provide buyers with specific information regarding the condition of a home’s structure and other features. These laws serve to protect buyers from the risk of loss associated with the hidden flaws, dangers, and weaknesses a property might contain.

However, sellers are only required to disclose known material defects, so unless hazardous materials from a nearby Superfund site have been found on a given property, it’s unlikely that the seller would mention the site on a disclosure form.

In other words, it’s up to you to determine whether a given property is near a Superfund site. Consider using our free Hazardous Site Locator to find out if there are any Superfund sites near you.

Where to Get More Information on a Specific Superfund Site

To facilitate operations with local and state governments as well as other federal agencies, the EPA has ten regional offices across the country, each of which is responsible for several states and in some cases, territories or special environmental programs.

Colorado is located in EPA Region 8, which also includes Montana, North Dakota, South Dakota, Utah, Wyoming, and 27 Tribal Nations.

If you need help finding information about any of the Superfund sites mentioned in this article, you can submit a request using the form located near the bottom of the Region 8 contact page. Otherwise, feel free to explore the EPA’s Superfund page where you can find detailed information on site cleanup efforts.

Paul

I’ve moved several times over the years, so I know just how stressful it can be to relocate. I want to help put your mind at ease. That’s why I research and write about all the things I think you should consider when moving to a new town.

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