Manufactured Gas Plants

Former St. Helena Manufactured Gas Plant

PG&E is working to address environmental impacts at the site of a former manufactured gas plant (MGP) located at 1301 Mitchell Drive in St. Helena, California that operated from 1883 to 1930. PG&E acquired the property in 1930 and used it as an electrical substation until 1989. All work is being conducted voluntarily by PG&E and is being overseen by the California Department of Toxic Substances Control (DTSC).

PG&E completed investigation work at the site and continues to cleanup soil and groundwater. In 2007, PG&E completed Phase One of a large-scale soil excavation and installed a treatment system to remove MGP residues from soil and groundwater at the site. PG&E expanded the system in January 2011 to remediate another portion of the site. PG&E will begin Phase Two of the cleanup in spring 2014 and expects to complete site remediation by fall 2014.

Parking Lot Ribbon Cutting

Under an agreement with PG&E, the City of St. Helena is using a portion of the remediated property as a parking lot through April 2014, when PG&E will need the parking area for Phase Two of the cleanup. This interim parking lot provides the City with free all-day parking for about 40 cars. PG&E and the City of St. Helena will discuss post-remediation site uses.

PG&E will continue to keep the community informed about this project through fact sheets, work notices and other outreach, as appropriate.

Additional Resources:

Site-related documents can also be found at:
St. Helena Public Library – Reference Desk, 1492 Library Lane, St. Helena (707-963-5244)

All MGP Locations
Chico Oakdale San Rafael
Colusa Oakland Santa Cruz
Daly City Oroville Santa Rosa
Eureka Red Bluff Selma
Fresno - 1 Redding St. Helena
Fresno - 2 Redwood City Stockton
Hollister Sacramento -1 Tracy
Lodi Salinas Turlock
Madera San Francisco - Adjacent To Potrero Vallejo
Marysville - 1 San Francisco - Beach Street Watsonville - 1
Merced San Francisco - Fillmore Watsonville - 2
Modesto - 1 San Francisco - North Beach Willows
Monterey San Francisco - Potrero Woodland
Napa San Luis Obispo - 1
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