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Site Description and History site, around the former gasoline UST, contains 2. Capping and Deed Restriction-This • Restoration of all removed paving; and
<br /> The site is approximately five acres and is located in elevated levels of VOCs in the subsurface. In addition alternative includes covering the entire site with a . Cleanup and restoration of all related structures
<br /> a commercial/industrial area of Tracy, California to VOCs in soil gas,there is evidence of minor new asphalt and/or concrete cap and recording a and work areas.
<br /> (Figure 1). PG&E uses the site as a service center for impacts to groundwater in the area of the former deed restriction on the site to protect and
<br /> storing and distributing material and equipment for gasoline UST.The soil gas and groundwater impacts maintain the cap. In addition, project controls designed to protect the
<br /> PG&E's work crews. The site is entirely fenced and around the former gasoline UST are likely to be 3. Targeted Excavation of Impacted Soil and surrounding community will be implemented during
<br /> includes a parking lot, storage area, and a garage/ eliminated as a result of soil removal activities. Off-site Treatment-This alternative includes cleanup activities and include the following:
<br /> office building. Human Health Risk Assessment excavation.of PAH,TPH,and VOC DTSC will oversee the preparation of a site-
<br /> From 1927 to 1930, a manufactured gas plant A Human Health Risk Assessment (HRA) shows contaminated soil in accessible areas of the site specific health and safety plan to guide all
<br /> operated at the site. This gas plant produced gas for that none of the chemicals present at the site pose a and backfilling excavated areas with clean fill. remediation work,
<br /> the lighting, cooking, and heating needs of local significant health risk to the on-site workers or The excavated soil would be transported off-site An environmental project manager will be
<br /> residents. The plant was dismantled and removed nearby populations. However, PG&E has selected to for treatment using a combination of heat to get on-site daily to monitor and approve all work;
<br /> from the roe between 1930 and 1934; cleanup the site to allow for unrestricted land use, to rid of contaminants and recycling.
<br /> property rry p Dust suppression activities will be performed
<br /> however, some residues of the gas-making process the greatest degree possible. In order to do this, 4. Targeted Excavation of Impacted Soil and including limiting the size of excavated areas for
<br /> remain on site. DTSC has determined that PAHs and VOCs in the Off-site Disposal—This alternative includes easy management, spraying water onto soil and
<br /> Site Investigations soil would require some form of cleanup if the site is excavation of PAH,TPH, and VOC work areas, stopping all work on windy days,
<br /> Since the early 1980s, PG&E has conducted redeveloped at a later date for residential purposes. In contaminated soil in accessible areas of the site covering soil piles, and covering all trucks leaving
<br /> investigations,monitoring,and remedial activities. order to restore the site to a condition that would be and backfilling the excavated areas with clean fill. the site;
<br /> Since 1986, a series of environmental investigations
<br /> protective of all future land uses, some form of soil The excavated soil would be transported off-site Workers will take measure to limit noise from have been conducted at the site. Results of soil cleanup is necessary.Y for disposal at an appropriately
<br /> ppro riately Permitted facility. construction including working only during
<br /> samples indicate that soil in six areas of the site Draft Removal Action Workplan Proposed Cleanup—Alternative 4: Soil hours allowed by the city and keeping noise
<br /> contain residues from former MGP operations and/or The objective of a draft RAW is to evaluate the Removal with Off-Site Disposal levels below city-allowed decibel levels; and
<br /> a release from an on-site gasoline underground nature and extent of impacts at the site and to Based on evaluation of the cleanup alternatives, On-site workers will monitor noise and airborne
<br /> storage tank(US 1).The residues include PAHs, identify a preferred alternative which prevents or targeted excavation of PAH,TPH, and VOC dust during all excavation activities and
<br /> TPHs, and VOCs. Soil impacts are generally found reduces potential risks to public health and the contaminated soil and backfilling the excavated areas throughout the daytime work schedule.
<br /> at a depth of one to 13 feet below the ground's environment. Cleanup alternatives are evaluated with clean fill is the preferred remedial alternative
<br /> surface,with the majority of impacts at a depth of based on a variety of factors including effectiveness, identified in the draft RAW. Implementation of this In the unlikely event that the implementation of the
<br /> one to three feet. ability to be implemented, regulatory agency and alternative would return the site to unrestricted land removal action at the site does not meet the project
<br /> Samples of soil as the air in between soil articles public acceptance, and cost. use, offering long term protection of the goal of returning the site to unrestricted land use, the
<br /> P g ( P ) environment and the surrounding community. following contingency planning activities, outlined in
<br /> indicate that one area in the northwest corner of the Before DTSC makes a final decision to approve, detail in the draft RAW, may be implemented for
<br /> modify, or deny a draft RAW,it is made available for The following activities would be performed under areas that could not be remediated due to
<br /> public comment during a 30-day public comment the proposed alternative: inaccessibility:
<br /> - period.All comments are reviewed and considered Performingan underground utility sure to
<br /> before the decision on the draft RAW is made. g ry eY Placement of land use covenants/deed restrictions
<br /> - identify all piping and other underground on the property;
<br /> xAM Cleanup Alternatives Considered and features;
<br /> Installation of extraction systems for the soil gas
<br /> w Recommended Removal and demolition of asphalt paving and groundwater to remediate residual impacts
<br /> E,
<br /> DTSC and PG&E evaluated a variety of alternatives within six areas of the site; not removed during the removal action; and/or
<br /> for cleanup of the soil and soil gas. DTSC examined Phased removal of 6,000 tons (approximately
<br /> ' 3 � Placement of an oxygen release compound in the
<br /> four cleanup alternatives were evaluated for the site, 200 truckloads) of soil and asphalt from depths water to stimulate biological remediation of
<br /> d as summarized below:
<br /> ranging between one and thirteen feet;
<br /> impacts in groundwater.
<br /> 1. No Action-This alternative was evaluated to Placement of excavated soil in a truck and/or bin
<br /> provide a baseline against which other cleanup for off-site disposal;Backfill and compaction of
<br /> alternatives can be compared. This alternative
<br /> - P excavated areas with clean, imported soil;
<br /> would involve no cleanup action and the site
<br /> would remain in its current condition.
<br /> Figure 1:Site Map
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