- November 14, 2022
McAlister GeoScience has obtained a No Further Action letter for a Former Caltrans Site in Hawthorne, California.
A property previously used as a California Department of Transportation (Caltrans) – owned Fueling Station was purchased by our client. The property previously had underground storage tanks (USTs) containing diesel. Previous investigations identified Total Petroleum Hydrocarbons in the gasoline range (TPH-g), and diesel range (TPHd), benzene, naphthalene and tertiary butyl alcohol (TBA) in analyzed soil samples. In February of 2020, three additional soil borings were advanced and groundwater samples were also collected. Concentrations of TPHg and TPHd were encountered in lower amounts compared to 2018, and TBA encountered in groundwater was not detected above reporting limits. In March of 2022, our team worked with a licensed drilling contractor to utilize hollow stem auger (HSA) and direct push drilling techniques to obtain soil, soil vapor, and groundwater samples. The samples were summited to state licensed laboratories to analyze the soil, soil vapor, and groundwater samples from the Subject Property.
Six borings were advanced, three each using HSA and direct push drilling techniques. Results from this most recent investigation found all significant VOCs well below their appropriate Environmental Screening Limits (ESLs). McAlister GeoScience drafted a final report making a case for the Regional Water Quality Control Board (RWQCB) Low-Threat Closure program.
Four years of work plans and monitoring and sampling was rewarded when based on the site-specific information and data available in GeoTracker and the Regional Water Board’s case file, the RWQCB concluded that this case met all the criteria of the State Water Board’s Low-Threat Underground Storage Tank Case Closure Policy and that a case closure determination for the site was appropriate.
Another satisfied McAlister GeoScience customer!