HAMILTON STREET BRIDGE SITE
111 N Erie St, Spokane, WA 99202

Capped portion of the site, looking northeast
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SITE BACKGROUND

The site is along the Spokane River under the Hamilton Street James E. Keefe Bridge. The site is made up of two adjacent properties, which housed the Spokane Manufactured Gas Plant and American Tar Company. We combined these two properties impacted by the business operations into the Hamilton Street Bridge site.

The Spokane Manufactured Gas Plant produced coal gas and carbureted water gas between approximately 1905 and 1948. The facility was used for mixing, storing, and distributing a propane-air system from 1948 to about 1956. In 1956, the company changed its name to Spokane Natural Gas Company and distributed natural gas from the facility. In 1958, Washington Water Power Company, now Avista Corporation, merged with the Spokane Natural Gas Company. Natural gas continued to be dispensed from the site until about 1963 when Richard Brown leased the property. In 1978, he purchased it, and in 1982 it was deeded to Spokane River Properties, of which he is a general partner.

The parties responsible for cleanup are Avista Corporation, BNSF Railway Company (BNSF), and Spokane River Properties, Limited.


Riverbank stabilization, looking east
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CONTAMINATION

Contaminants in soil included volatile organic hydrocarbons (VOCs) and semivolatile organic hydrocarbons (sVOCs), polycyclic aromatic hydrocarbons (PAHs), and metals.

Groundwater samples taken from points surrounding the soil-contaminated area detected relatively few of these materials. Contaminants that were found leaching into the groundwater are undergoing biodegradation and attenuation through physical, chemical, and biological processes. 

Investigations show that the Spokane River is not being adversely impacted by the site.


Monitoring wells and capped portion of the site, looking east
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CLEANUP

From 1997 to 2006, the parties responsible for cleanup completed several cleanup actions. A compacted gravel surface serves as a cap that blocks human exposure pathways (ingestion, contact) to contaminated soils.

 
A restrictive covenant prohibits activities that might result in the release of contaminants. They also serve to ensure the long-term integrity of the cap over contaminated soil and the two building foundations that remain as caps over contamination.

When restrictive covenants are used, Ecology visits the site at least every five years. In 2010, Ecology completed the first periodic review and determined that the remedy was still protective of human health and the environment. The surface appears in acceptable condition, with no signs of excavation or other disturbance of the capped areas. No repair, maintenance, or further actions have been required. 

In 2015, Ecology completed the second periodic review and concluded that the cleanup actions completed at the site are protective of human health and the environment. Soil cleanup levels have not been met; however, the cleanup action does comply with standards, since the long-term integrity of the containment system is ensured, and the requirements for containment technologies have been met.

Total arsenic and dissolved arsenic were reported above cleanup levels during the March 2015 sampling event. Other recent sampling events have shown concentrations of arsenic, mercury, cyanide, and PAHs that exceed state standards. Fluctuations of contaminants above state standards, particularly in wells adjacent to the Spokane River, should be further evaluated to determine if they are impacting the Spokane River.

The site is currently planned for development, during which the limitations in the restrictive covenants will prevent uses that may expose hazardous materials.


Hole cut in security fencing, looking west
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Map showing site location as Spokane County, WA SITE INFORMATION

Map

View Electronic Documents

Cleanup Site Details Report

Facility Site ID: # 84461527

Cleanup Site ID: 3509

Location:
Spokane, Spokane County

Status: Construction Complete-Performance Monitoring   Get definitions of Status terminology

Contacts:
Christer Loftenius
Site Manager
(509) 329-3543

Erika Beresovoy
Public Involvement Coordinator
(509) 329-3546


Document Repositories:

Eastern Regional Office
N 4601 Monroe St
Spokane, 99205-1265
(509)329-3415