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. The MGP 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 clean up 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 May 2014 and expects to complete site remediation by fall 2014. During this work, PG&E will excavate impacted soil and backfill these areas with clean, imported fill. Area residents and businesses may experience some short-term noise and vibrations typical of heavy construction work as well as a small increase in area truck traffic. Activities will be coordinated with nearby businesses and the City of St. Helena to limit community impacts to the greatest extent possible.

Parking Lot Ribbon Cutting

Under an agreement with PG&E, the City of St. Helena used a portion of the remediated property as a free, all day parking lot through April 15, 2014.PG&E and the City of St. Helena will be discussing possible 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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