Manufactured gas plants
Former St. Helena manufactured gas plant
Project overview: PG&E has finished cleanup of a former manufactured gas plant (MGP) that operated almost a century ago at 1301 Mitchell Drive in St. Helena (site) and continues to conduct post-remediation monitoring activities, including groundwater sampling, with oversight provided by the California Department of Toxic Substances Control (DTSC).
Former St. Helena MGP site after remediation.
Currently, PG&E is exploring site redevelopment options in coordination with the City of St. Helena. As we move forward, we keep the community informed of the status of the site through fact sheets, work notices, and other outreach, as appropriate.
Site history: The St. Helena MGP operated from 1883 to 1930. PG&E acquired the property in 1930 and used it as an electrical substation until 1989. In 2007, PG&E completed a soil excavation and installed a treatment system to remove MGP residues from soil and groundwater at the site. The treatment system successfully operated until 2012 and was later dismantled and removed. In 2014, PG&E completed its second and final phase of soil excavation thus completing the remediation of the site.
The St. Helena MGP circa 1910.
There is no indication that PG&E's former MGP sites pose any health concerns to the public, based on our testing, experience, and extensive review of medical literature.