The Titan 1-A Missile Facility was completed in 1962 and consisted of three 160-foot-deep missile silos, with adjacent underground and above-ground features including storage tanks, distribution lines, electrical wiring, water supply, communication lines, and wastewater collection facilities. The Titan 1 rocket engines were powered by a liquid oxygen/Refined Petroleum-1 liquid fuel mixture.
In 1968, the facility was declared excess and dismantled. Placer County acquired a parcel of the former missile complex that same year. Adjacent parcels of the former facility have since been acquired by private owners.
A private, subsurface investigation in 1991 identified trichloroethene (TCE) in groundwater samples collected from along the drainage swale that passes through the Crocker Knoll property.
In 1994, USACE Sacramento District began a series of remedial investigations of the soil, soil vapor, and groundwater (including monitoring well installations) as part of the Formerly Used Defense Sites (FUDS) program.
In 2001, USACE began operation of a small-scale pilot groundwater extraction and treatment system. The extraction system was composed of four extraction wells, two 50-foot-long extraction trenches, and one 200-foot-long extraction trench. The groundwater extraction pilot test operated for approximately three years, over which time approximately 10 pounds of TCE were removed by extracting impacted groundwater.
In 2002, a Soil Vapor Extraction test was performed at four wells to test soil permeability/vacuum radius of influence.
USACE performed two bench-scale studies in 2005 testing chemical oxidation and enhanced bioremediation effectiveness on site contamination.
Fieldwork stopped in 2009 to investigate other potential sources of the TCE contamination. A project is not eligible for the FUDS program if contamination is caused by other parties.
USACE re-initiated its Titan 1-A FUDS project and associated remedial investigation activities in 2018. 19 new groundwater monitoring wells were added to the 14 pre-existing monitoring wells and 24 new soil vapor probes were installed to begin collecting new data to regularly assess contamination status across varying conditions.