HomeMy WebLinkAboutC_Monster Road PE Letter_Clean Up RemediationPage 1 of 2
January 8, 2021
Jill Ding
City of Renton
Community and Economic Development
1055 S. Grady Way
Renton, WA 98057
SUBJECT: ENVIRONMENTAL REMEDIATION CERTIFICATION FOR OCCUPANCY
601 MONSTER ROAD SW BUILDING/LUA18 -000237
Dear Ms. Ding:
This letter updates a letter submitted to you November 12, 2019, fulfilling Mitigation Measure #3 in
the State Environmental Policy Act (SEPA) Determination of Non-Significance – Mitigated (DNS-M)
for the 601 Monster Road project.
Mitigation Measure #3 calls for Prologis to provide a No Further Action (or equivalent) letter from
the Voluntary Cleanup Program (VCP) of the Washington State Department of Ecology (Ecology)
confirming compliance with the Model Toxics Control Act (MTCA) and any other applicable
cleanup law, prior to any occupancy of this site and prior to the issuance of a Temporary or Final
Certificate of Occupancy.
This letter provides my certification of environmental remediation completion and confirmation
of the protectiveness of the site under state law, to support your issuance of a Certificate of
Occupancy. This is submitted as an equivalent letter to fulfill Mitigation Measure #3.
Prologis is remediating the site as an independent action under Ecology’s VCP. Under this
process, Ecology review and issuance of a No Further Action determination for the Site will not
occur until after completion of at least 1 year of groundwater monitoring following site
remediation. This Ecology review will occur after occupancy of the new building at the property ,
which is common practice for redeveloped contaminated properties . Prologis has continued to
coordinate with and provide updates to Ecology on the status of the cleanup process and
submitted an application to enroll in the VCP on December 23, 2020. The site is registered with
Ecology as Cleanup Site #11481, and all historical and recent site data have been submitted to
Ecology’s Environmental Information System database. During a recent meeting with the Ecology
Northwest Regional Office VCP Unit Supervisor, Louise Bardy, and VCP Site Manager, Mike Warfel
((425) 649-7257, michael.warfel@ecy.wa.gov), Ecology expressed support for the proactive
approach taken by Prologis with the independent cleanup and confirmed the future process for
their review of groundwater monitoring data prior to issuance of a No Further Action
determination.
Jill Ding, City of Renton
January 8, 2021
Page 2 of 2
As a Professional Engineer in Washington State, I am overseeing this cleanup action. I certify that
the 601 Monster Road property has been remediated in full compliance with MTCA and other
applicable cleanup laws. The “Prologis-Monster Road Site – Soil and Groundwater Remediation”
action has been completed in accordance with plans, specifications, and permit requirements.
Confirmation samples were collected from the sidewall and bottom of the excavation as
required, and final analytical results confirmed that applicable soil cleanup levels required by
MTCA were reached in all areas of the excavation. Notification of completion of the Soil and
Groundwater Remediation was provided to City of Renton on May 16 , 2019. Additional
monitoring wells were installed in June and July of 2020, and quarterly groundwater monitoring
began in September 2020.
In conjunction with soil removal activities, precautionary mitigation actions and data collection
have been implemented to confirm that there is no risk of vapor intrusion to the building at
contaminant concentrations of concern. Following the excavation and backfill, a heavy-duty
vapor intrusion barrier designed to prevent potential transmission of volatile organic compounds
was installed as a precautionary measure over the excavated area and other areas where new
building slab was installed. As further precautionary steps to rule out potential vapor intrusion,
a sub-slab soil vapor investigation was conducted throughout the building footprint in
September 2019, and soil vapor data were collected adjacent to the building’s north edge in
December 2020. The vapor monitoring results indicate no exceedances of applicable screening
criteria and full compliance with vapor intrusion assessment requirements in accordance with
Ecology guidance under MTCA. We conclude that there are no remaining concerns related to
vapor intrusion.
I certify that there are no conditions related to site contamination that would affect safe
occupancy of the new building on the property. It is fully appropriate, with this certification, for
you to issue the Certificate of Occupancy. Please feel free to contact me with any questions.
Sincerely,
Kate Snider, PE
Principal
Copies: Justin Kirk, Prologis