The periodic report for the Brumfield Twidwell site shows that cleanup work remains effective in protecting human health and the environment.
In the past, the site was a service station, repair, and sales shop for cars. Currently the site is a commercial property and this use is not likely to change in the future.
In 2005, Ecology found gasoline-range petroleum hydrocarbons in soil and groundwater at the site. The owner removed about 2,079 tons of contaminated soil and disposed of it offsite. Two underground storage tanks (USTs) were removed and three USTs were closed in place.
In 2012, an oxygenating compound was injected into groundwater monitoring wells to speed-up the microbial degradation of the remaining contamination.
In 2012-2013, the groundwater was monitored quarterly and continued for at least one year. Petroleum hydrocarbon concentrations in groundwater decreased over time until contaminant concentrations either were below state cleanup levels or not detected.
In 2013, we determined the cleanup was complete and issued a letter of satisfaction for the cleanup. In 2014, we removed the site from the Hazardous Sites List.
An environmental covenant was filed for the site in 2006. Among other things, the covenant prohibits activities that could result in the release of contaminants on the site. Groundwater on the site may not be used for drinking, agriculture, or industry.
Periodic review process
We conduct a periodic review at least every five years at cleanup sites where some contamination remains, as required by the Model Toxics Control Act (MTCA). The purposes of the review are to evaluate site conditions and to ensure continued protection of human health and the environment.
We will review comments received during the comment period and make recommendations for suggested changes. The periodic review will become final if no significant changes are made. An additional public comment period will be held if significant changes are made.
We will hold a public meeting if 10 people request one.