5021 Colorado Ave S, Seattle, WA 98134-2404

Photo of the east side of the building, facing northwest from Colorado Avenue South
Please click on the photo for a larger view


The former Liquid Carbonic Carbon Dioxide facility is located at 5021 Colorado Avenue South, Seattle, Washington. The facility was constructed in 1910, and Liquid Carbonic began installing equipment in 1930 for the manufacture of solid and liquid carbon dioxide. The building is currently leased to multiple light industrial and commercial tenants. The property is located in an industrial area of south Seattle.

Soil and groundwater impacted with total petroleum hydrocarbons (TPH) and metals were discovered in 1993 in the vicinity of three underground storage tanks (USTs).


A remedial action was conducted in 1996. Approximately 300 cubic yards of petroleum contaminated soil (PCS) was excavated and removed from the Site. Excavation areas included two in the shop area and four in the engine room of the Liquid Carbonic facility.

Samples collected from the limits of the excavations indicated that TPH concentrations remain which exceed the site-specific cleanup levels. Excavation of impacted soil was limited in some areas by the proximity of large compressor foundations and roof support footings.

Protective capping was considered the remedial action for the remaining soil contamination. Asphalt covers the majority of the Site that does not fall under the building footprint.


Groundwater monitoring was started in 1995, and continued quarterly as part of the ‘No Further Action’ (NFA) determination and Restrictive Covenant (also known as an Environmental Covenant) filed in 1997. Ecology issued a second NFA determination in August 2000, stating that groundwater monitoring was no longer required at the Site. The Restrictive Covenant was placed to ensure remedy performance and to restrict activities that might result in exposure to contaminants.

This Site was cleaned up through the Independent Remedial Action Program (IRAP), Ecology’s original Voluntary Cleanup Program. This program enabled owners of contaminated sites to meet state cleanup standards independently and to receive technical guidance from Ecology during the process.


A periodic review is conducted every five years following a cleanup action when institutional controls are used as part of the remedy, as required by the Model Toxics Control Act (MTCA). The purpose of the periodic review is to evaluate current site conditions and to ensure continued protection of human health and the environment.


The remedial actions completed at the Site appear to be protective of human health and the environment.

Soil and groundwater cleanup levels have not been met at the Site; however, the cleanup action was determined to comply with cleanup standards under WAC 173-340-740(6)(f), since the long-term integrity of the containment system is ensured, and the requirements for containment technologies are being met.

The Environmental Covenant for the property is in place and continues to be effective in protecting public health and the environment from exposure to hazardous substances, as well as protecting the integrity of the remedial action.

Based on this periodic review, Ecology has determined that the requirements of the Environmental Covenant continue to be met. No additional cleanup actions are required by the property owner at this time. It is the property owner’s responsibility to continue to inspect the property to assure that the integrity of the remedy is maintained.


Check if electronic documents are available for this site by clicking “View Electronic Documents” in the right-hand column. To request an in-person review of the site file at the Ecology Northwest Regional Office, please send an email with the site name, address, and facility site ID number to


Map showing site location as King County, WA SITE INFORMATION


View Electronic Documents

Cleanup Site Details Report

Facility Site ID: # 8667316

Cleanup Site ID: 5465

Seattle, King County

Status: No Further Action   Get definitions of Status terminology

Tamara Welty
Periodic Review Coordinator
(425) 649-7023

Document Repositories:

Northwest Regional Office
3190 160th Ave SE
Bellevue, 98008-5452