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City of Fremont

City of Fremont

  • Groundwater Monitoring & Sampling Work Plan

  • Soil Vapor Survey

  • Environmental Site Assessment

  • Contracting with Licensed Driller

  • Report Preparation

  • Site Closure Activities

Fire Station No. 1, Fremont, California

Stratus Environmental, Inc. was awarded a Master Service Agreement from the City of Fremont to provide soil and groundwater investigation, clean-up, and monitoring services on an on-call basis. Our work with the City included a piece of property that was developed as a fire station and is in active use by the City of Fremont Fire Department.

In the past, an underground storage tank was located near the south corner of the station building, and was removed in approximately 1986. Following the discovery of hydrocarbon impact to soil and groundwater, two soil borings and twenty groundwater monitoring wells were installed at the site and in the vicinity.


During the early 1990’s, onsite wells were used for soil vapor extraction. In May 2006, eight of the groundwater monitoring wells were destroyed, and groundwater monitoring was conducted during 2007, 2008, and 2009, and again in 2013 by Stratus.  Stratus’ 2013 monitoring report recommended evaluation for case closure based on the results of the March 2013 sampling event.

Stratus personnel conducted a soil vapor survey at the site near the source area and near the fire station dormitory. Stratus prepared a work plan that outlined the planned installation of three soil vapor sampling points and sampling activities using Department of Toxic Substances Control Post Run Tubing sampling methods.  The results of the 2015 soil vapor survey indicated no significant risk to occupants of adjacent buildings from petroleum hydrocarbon vapor migration to indoor air. The objectives of the soil vapor survey were to gather data needed in order to meet the California State Water Resources Control Board’s Low-Threat Closure Policy criteria for indoor air to evaluate any possible human health risk to the occupants of buildings nearby the impacted area.


Based on the results of groundwater monitoring and the soil vapor survey, Stratus recommended case closure.  In March 2017, the Alameda County Water District (ACWD) concurred with the recommendation for closure, and Stratus destroyed the remaining monitoring wells in April and May 2017.  The ACWD sent their recommendation for case closure to the San Francisco Bay Regional Water Quality Control Board (RWQCB) in July 2017, and the RWQCB forwarded their closure letter to the City of Fremont on August 15, 2017.

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