ConocoPhillips is working with the City of Seattle and City Investors (Vulcan) to complete the cleanup of historical underground releases of fuel at the ConocoPhillips and City Investor properties located on the city block surrounded by Westlake Avenue North, Mercer Street, Terry Avenue North, and Valley Street.

Currently, this block is mostly vacant, but there is an active parking lot on the corner of Mercer Street and Terry Avenue North. Due to the increase in public and private development in the South Lake Union area, ConocoPhillips has decided to expedite completion of the cleanup effort. The cleanup is being performed in compliance with all applicable Washington State Department of Ecology requirements.

BACKGROUND

The cleanup actually began immediately following the discovery of an underground gasoline line leak in 1980 by Unocal, the service station property’s owner at the time. Cleanup continued over the years with the implementation of various remediation projects, including the installation of an underground soil vapor extraction system. ConocoPhillips subsequently purchased the service station and parking lot area on the southern half of the block from Unocal in 1997 and continued the cleanup effort.

Several years of environmental investigations took place to determine the effectiveness of the various remediation efforts. The investigations concluded that the soil vapor extraction system had been effective in cleaning up the contamination where the system was applied. Numerous environmental studies performed also indicated that the contamination did not reach Lake Union.

Ongoing investigations and monitoring programs indicate that the site poses no known risk to human health. Additionally, the historical releases at the site do not impact residential water supplies as property owners in the area receive their domestic water from the City of Seattle’s municipal water supply.

PROJECT WORK

Cleanup activities completed in early 2007 (Phase 1) focused on the impacted areas within the city rights of way of Westlake Avenue North and Terry Avenue North between Mercer Street and Valley Street. Work during this phase included the excavation and removal of petroleum hydrocarbon impacted soil and groundwater, and the installation of underground cleanup systems, along with complete restorations of the rights of way.

This next scope of work (Phase 2) is focused on the impacted areas in the city block bounded by Westlake Avenue North, Valley Street, Terry Avenue North, and Mercer Street. As before, this work will include the removal of petroleum hydrocarbon impacted soil and ground water. We are working closely with the Seattle Department of Transportation to minimize traffic and business interruptions throughout our cleanup activities.

If you have any questions on this project, or if you would like more information, please visit www.westlakemercercleanup.com or call (206) 540-5262.