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Cleanup Areas and Recent Activities

Former Potrero Power Plant | Site Overview | Cleanup Areas & Recent Activities | FAQ | Archive

The site has been divided into seven work areas to allow remediation to proceed in those areas unimpeded by existing structures.

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We have made significant progress on the environmental investigation and remediation of the site. Most investigation activities have been completed in the accessible areas. Other remediation activities, including conducting feasibility studies, health risk assessments, and site management plans, are in various stages of completion. Recent remediation milestones include:

Northeast Area (GenOn and Port of San Francisco Owned)

This area includes the northeastern corner of the Potrero Power Plant property, the shoreline and the southeastern portion of Pier 70 owned by the Port of San Francisco. An extensive soil and groundwater investigation of the area is now complete. A draft Feasibility Study , which provides an evaluation of various cleanup options for the site, was recently submitted to the Water Board. It will be available for public review in September or October. The Water Board and PG&E will notify the public when the comment period opens.

PG&E considered a number of important criteria when evaluating potential cleanup options. These included impacts to the community, estimated time for completion, impacts to future development, and required maintenance.

Under the preferred cleanup approach (Solidification with Limited Excavation), the majority of MGP residues on the Power Plant Property would be treated in place using a solidification agent and the majority of MGP residues found on the Pier 70 property would be excavated and removed. The need for two distinct cleanup approaches is due to the depth and accessibility of residues. This cleanup approach when implemented would protect the Bay by eliminating the potential for movement of MGP residues.

The preferred approach would also include the installation of a durable ground cover in areas where additional residues are present, continued groundwater monitoring and institutional controls such as a site management plan that provides the property owner background about the site and guidance for future construction and maintenance.

We look forward to working with the community when evaluating the final cleanup solution for this area. We are committed to keeping the community informed and involved throughout the investigation and cleanup.

Shoreline Cleanup and Stabilization

In 2010, PG&E conducted an interim cleanup action along a portion of the shoreline adjacent to the GenOn Potrero LLC and Pier 70 properties. MGP residues (asphalt-like material) exposed along the shoreline were removed to prevent them from eroding and entering the Bay. With the residues removed, the shoreline was restored and further protected from erosion by placing a specialized fabric layer over the ground surface followed by pieces of stabilizing rock.

Switchyard and General Construction Yard Areas (PG&E Owned)

The Switchyard and General Construction Yard remain an integral part of San Francisco's electrical infrastructure. Remediation activities in the Switchyard and General Construction Yard have been completed. In order to prevent exposure to underlying soil, the site is currently covered by gravel, concrete or asphalt. A Site Management Plan and Deed Restriction that restricts this area to commercial and industrial uses was approved by the Water Board and then submitted to the City and County of San Francisco in October 2011. The Water Board has issued a completion (i.e., No Further Action) letter for environmental work for this portion of the site, indicating that no further remediation work is needed.

Hoe Down Yard (PG&E Owned)

Investigation activities for the Hoe Down Yard (a PG&E construction and equipment storage area) have been completed and approved by the Water Board. As part of this, a final Screening Level Human Health Risk Evaluation was approved by the Water Board in February 2012. A Site Management Plan for the area was approved by the Water Board in July 2012. In addition, a Deed Restriction for the area was recently submitted to the Water Board. We expect regulatory closure for this area – to be completed by the end of this year.

Station A Area (GenOn Owned)

Site investigations are complete and a Human Health Risk Assessment was approved by the Water Board in February 2012. The majority of Station A is capped by asphalt, concrete and structures.A Site Management Plan ant Deed Restriction will be submitted to the Water Board this summer. The completion of remediation activities is expected in 2012.

Power Generation Facility (GenOn Owned)

This area includes the recently shut down Unit 3 power plant and immediate surroundings. Some soil and groundwater investigations have already been conducted in this area and additional investigations will take place once the former plant is demolished by GenOn.

Tank Farm Area (GenOn Owned)

This area includes three large above-ground fuel tanks formerly used to house fuel oil. Limited soil and groundwater investigations have been conducted in this area. Additional investigations are anticipated once the above ground tanks are removed by GenOn.

Offshore Sediments Investigation Area

This area includes sediments in San Francisco Bay near the former power plant property. PG&E conducted four phases of sediment investigations including the most recent one conducted in July 2012. A remedial investigation report will be prepared in 2013, and a feasibility study will be prepared in 2014. A Remedial Action Plan, remedial design and permitting will be prepared in 2015 and 2016. The public will be invited to comment on the feasibility study by the Water Board in advance of it final approval. Remediation is anticipated in 2017.