Ecology invites you to review and comment on the following documents:
Additional information is available at the Portac site webpage and the fact sheet.
The site was a log yard and sawmill. The site was contaminated when slag (waste) from the Asarco smelter was brought to the site to support roads for heavy equipment. A wood preservative used at the sawmill containing pentachlorophenol (PCP) contaminated groundwater.
Agreed Order DE 15816 requires the Port of Tacoma (potentially liable person) to implement and maintain the cleanup actions described in the Cleanup Action Plan.
The cleanup plan describes how to prevent exposure of stormwater and surface water to arsenic-contaminated soil and groundwater, and prevent exposure of surface water to PCP-contaminated groundwater. The stormwater collection system will be improved and a permeable reactive barrier will be installed next to Wapato Creek on the northwestern corner of the site. The barrier reduces arsenic in groundwater as it moves through the barrier.
Groundwater will be monitored downgradient of the barrier to ensure its effectiveness and show that PCP contamination continues to decrease.
When the site is ready for redevelopment, a new improved cap will be constructed under a separate agreed order.