Montlake Texaco

Ecology issued a Property No Further Action (NFA) opinion letter on May 21, 2024. Contamination on the Property was successfully remediated to meet Ecology cleanup levels; however, groundwater contamination remains downgradient of the Property and therefore that status of the Site remains “cleanup started.” 

The Site consists of property formerly occupied by a gasoline service station and the Montlake Market. Earliest available records indicate that the Property was initially developed as early as 1926 and might have included gasoline service station activities at that time. King County Assessor records show the Montlake Market building and the gasoline station building were constructed in 1937 and 1952, respectively. The service station building was remodeled in approximately 1980 to incorporate bays for auto servicing and repair.

WSDOT acquired the property in June 2019. Business activities in these two structures ceased at the end of 2019 and the structures were demolished in early 2020. The WSDOT contractor for the SR 520 Montlake Project is currently using the property for construction equipment staging and vehicle parking.

Site investigations completed from 2016 through 2023 documented the extent of soil and groundwater contamination at the site. Leaks and spill associated with service station activities on the property were identified as sources of the contamination. Four underground storage tanks associated with the former service station were removed in 2023, along with petroleum-contaminated soil that was disposed at a permitted off-site facility. Oxygen-release compound (ORC) was added to the excavation backfill to enhance the remediation of contamination in groundwater.

Confirmation soil and groundwater samples documented compliance with cleanup levels on the Property. However, groundwater in one downgradient monitoring well northeast of the Property continues to show exceedances of cleanup levels for petroleum compounds. Future sampling of this monitoring well is planned to assess anticipated declines in concentrations as the ORC treatments on the Property continue to affected the groundwater system.

Total petroleum hydrocarbons (TPH) in the gasoline, diesel, and oil ranges (TPH-G, TPH-D, and TPH-O); benzene, toluene, ethylbenzene, and xylenes (BTEX); and carcinogenic polycyclic aromatic hydrocarbons (cPAHs) into the Soil.

TPH-G, TPH-D, TPH-O, BTEX, cPAHs, and arsenic into the Groundwater.

This site is in our Voluntary Cleanup Program, which provides technical help to owners of contaminated sites.

Voluntary Cleanup Program customers pay fees to cover our costs for technical help and reviewing cleanup reports. Sites in this program must meet the same cleanup standards as sites Ecology manages under legal orders.