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13th Street Plaza

The City of Boulder is conducting a voluntary cleanup at 13th Street and Canyon Boulevard to remove the remaining infrastructure, soil, fluids, and debris from the former Federal Gas Company manufactured gas plant site. Environmental investigations of the site revealed structures were left in place with contamination and that levels of several contaminants exceeded state groundwater standards, which has necessitated remediation.

Read the 13th Street Plaza Remediation Factsheet pdf.

View the map of the area and injection wells pdf.

Current Status

In June 2019, the city completed a second set of in-situ chemical oxidation injections at the site utilizing 27 injection wells. The 27 injection wells include wells used in the first set of injections in 2017 plus four new injection wells installed in June 2019 to address areas of higher concentrations of constituents of concern (COCs). Third quarterly sampling and subsequent quarterly monitoring will determine the effectiveness of the second set of injections.

The permanent plaza and parking lot will be reconfigured to improve circulation and parking for Boulder Farmers’ Market patrons. The long-term future of the site will be part of the public planning process for the Boulder Civic Area.

If you have any questions about the remediation work, please contact Joe Castro, at 303-441-3163 or at [email protected] or by mail to:

Joe Castro, Facilities and Fleet Manager
Department of Public Works
1720 13th Street, PO Box 791
Boulder, CO 80306

Project Details

Remediation Process

City contractors are conducting remediation activities at the 13th Street Plaza site as part of a Voluntary Cleanup Plan (VCUP). The first phase of remediation activities was completed in April 2014. The second phase of work was completed in fall 2017. The site will be monitored for two years, and additional treatment will be scheduled as needed.

Voluntary Cleanup Plan (VCUP)

Phase I

The Colorado Department of Public Health and Environment (CDPHE) approved the City of Boulder’s VCUP and will confirm that the plan has been successfully implemented once remediation activities have been completed.

The VCUP outlines remediation on the site, including the removal of manufactured gas plant infrastructure, soil, fluids and debris, as necessary, to address impacts to groundwater quality. 

The city chose Envirocon to perform the remediation activities. Envirocon scientists and engineers have considerable experience with the Colorado Voluntary Cleanup Program and manufactured gas plant site cleanups.

Phase II

On July 13, 2016, the City of Boulder submitted a Voluntary Cleanup Plan Second Interim Remediation Report (Second Interim Report) pdf to the Colorado Department of Public Health and the Environment (CDPHE), summarizing results of a pilot study and ongoing groundwater monitoring activities performed at the 13th Street Plaza property (Plaza Site) from September 2014 through March 2016. The Second Interim Report also includes the results of an analysis completed to evaluate additional remedial alternatives to address residual soil and groundwater impacts at the Plaza Site (the “Remedial Alternatives Analysis”).

The public comment period closed in late August 2016 and the following comments were received:

The city has retained XDD Environmental, a consultant with expertise in underground injection remediation, to oversee the underground injection remediation. Cascade Technical Services will perform the work, which includes injecting low levels of an oxidant in 26 underground injection wells. XDD Environmental will evaluate the results of the underground injections and ensure that they were effective in remediating the remaining contamination.

Public Health

There are no health risks to employees, vendors, or visitors at the Boulder Farmers’ Market and Dushanbe Teahouse. The area where the gas manufacturing equipment was located is covered in pavement, preventing exposure to any remaining materials.

There are no domestic drinking water wells on the site or within half a mile of the site. Tap water at the Dushanbe Teahouse and neighboring buildings on and in the vicinity of the site comes from the City of Boulder's drinking water system, not from individual groundwater sources in the area.

Manufactured Gas Plant

The Federal Gas Company generated gas at the site from about 1902 until the plant was demolished in 1953. The City of Boulder purchased the property in 1975 and installed the Dushanbe Teahouse and the 13th Street Plaza in 1997. Prior to environmental investigations in 2012 and 2013, city staff believed that the previous property owners had removed all above-ground structures from the site by 1962.

Property Ownership

The City of Boulder is the current property owner and the property is occupied by the 13th Street Plaza, Dushanbe Teahouse, and a parking lot to the east.

City staff believes the property was an alley and parking lot when the City of Boulder purchased the property in 1975, and has no knowledge of what previous property owners knew or did not know about the subsurface conditions. It appears that the property remained undeveloped until 1997, when the city installed the Dushanbe Teahouse and the 13th Street Plaza at the property.

There have been several property owners at this location over the years, including, among others, the Public Service Company of Colorado (a wholly owned subsidiary of Xcel Energy) and its predecessor.

Cost of the VCUP

Staff estimates that it will cost approximately $4.3 million to fund the VCUP for remediation of the former manufactured gas plant at the 13th Street Plaza site. The City of Boulder will absorb the initial costs, with cost-sharing to be pursued with other responsible parties.

The cost of cleanup will be part of the city’s ongoing discussions with Xcel Energy about the VCUP implementation. At this time, the city and Xcel Energy have not agreed upon a general cost-share estimate for the project. The two parties were not able to agree on terms quickly enough and the city did not want to delay work in order to work out what would be a discrete agreement for a relatively small amount of cleanup work.

Environmental Investigations

The City of Boulder and Xcel Energy have been working together to investigate whether any materials from the former manufactured gas plant are migrating from the site. This has involved investigating the remaining underground features from the former manufactured gas plant, and any associated groundwater and soil contamination.


For more information, contact Facilities and Fleet Manager Joe Castro at [email protected] or 303-441-3163.