Manufactured gas plants

In the mid-1800s and early 1900s, manufactured gas plants (MGPs) existed throughout California and the United States. These plants used coal and oil to produce gas for lighting, heating and cooking. At that time, this technology was a major step forward. It helped revolutionize street lighting, enhance public safety and enabled businesses to work into the night.

In addition to gas, MGPs produced byproducts including coal tar and lampblack. The byproducts that could not be sold were removed for disposal or remained at the MGP site. With the arrival of natural gas around 1930, most of the PG&E MGP sites were no longer needed. They were closed down. As was common practice at the time, byproducts of the gas-making process were left buried on-site.

In the 1980s, the United States Environmental Protection Agency (EPA) conducted research of these sites. They found that, in some cases, residues from these facilities may remain on-site and require remediation.

Following the EPA study, PG&E established a voluntary program under the oversight of the California Department of Toxic Substances Control (DTSC). The program identified the location of our former MGP sites and began a process of testing soil and groundwater from those sites.

To date, PG&E has identified 43 MGPs we formerly owned or operated. We are working to ensure that any potential impacts to the environment from these MGPs are addressed in accordance with today’s regulatory standards. DTSC or its sister agency, the California Regional Water Quality Control Board (Water Board), determine when remediation activities are necessary. We then work closely with the regulatory agency, county and city officials, and nearby businesses and residents to design the most effective remediation program for the site.

Our sites are in various stages of remediation, including:

• Investigation
• Remedial alternative evaluation and design
• Active cleanup
• Post remediation monitoring
• Project completion

Bakersfield MGP

PG&E is preparing to clean up the site of a former MGP located at 800 and 820 20^th Street in Bakersfield. The MGP operated at the site from 1888 through 1910. PG&E purchased the property in the mid-1940s. We demolished the MGP structures and used the site for automotive repair work until 1967. The site was then sold to a third party that continued to use the property for autobody repair and servicing. PG&E repurchased the property in 2019 to conduct environmental investigations and cleanup work. PG&E will demolish on-site buildings in spring 2024 to support future cleanup work. We are also working with DTSC to develop a cleanup plan for the site. It will be available for public review and comment in summer 2024.

Napa MGP

PG&E is voluntarily cleaning up the site of a former MGP that operated near Riverside Drive and Elm Street in Napa. This work is conducted with the approval and oversight of DTSC and the City of Napa. The cleanup plan addresses both soil and groundwater at the site and the adjacent property, the Elm Street Townhomes. The cleanup plan includes:

• Excavation of soil that was impacted by gas-making activities and off-site disposal
• Replacement of excavated soil with clean fill
• Treating on-site deeper impacted soil in place by mixing soils with a cement-like stabilizing agent to protect groundwater

Groundwater will continue to be monitored for a minimum of five years after the cleanup.

Current conditions do not present a health risk to current site users or former residents at the Elm Street Townhomes. The cleanup will:

• Protect long-term public health and the environment
• Minimize impacts to the local community
• Support future site redevelopment

Learn more in the Napa MGP DTSC work notice (PDF).

Vallejo MGP

PG&E completed the cleanup of a former MGP that operated near Curtola Parkway and Sonoma Boulevard in Vallejo in January 2024. The work addressed the contamination of soil and groundwater from historic gas-making activities. Work included a combination of excavation and off-site disposal of shallow soil and adding a cement mixture to solidify impacts to deeper soil in place. Excavated areas were backfilled with clean, imported fill and work areas were restored. This work protects long-term public health and the environment and supports future site redevelopment. Remaining boat launch parking lot restoration work is being coordinated with the City of Vallejo.

Learn more about the work completed in the Vallejo MGP DTSC work notice (PDF).

San Francisco Fillmore and North Beach (Uplands) MGPs

The former Fillmore MGP operated in what is now known as the Marina District in San Francisco, near the area west of Fillmore and Bay Streets. The former North Beach MGP operated near the area north of Bay and Buchanan Streets. A portion of the Fillmore facility was located on an area now covered by asphalt at the southeast corner of the Marina Middle School property.

In 2010, PG&E began a voluntary program under the oversight of DTSC to sample for residual materials that may be present at the site of these former MGPs. If DTSC determines that remediation activities are necessary, we:

• Work closely with the agency, residents, property owners and city health and environmental departments
• Design the most effective remediation program for the specific site

This is an ongoing program with remediation and restoration of sites within the former Fillmore and North Beach MGP footprints.

Learn more from the latest DTSC work notices:

• Groundwater Sampling Work Notice (PDF)
• Soil and Soil Vapor Sampling on Private Properties Work Notice (PDF)

San Francisco North Beach (Sediments) MGP - East Harbor and Outside East Harbor

PG&E is planning to dredge impacted sediments in the Marina East Harbor and Outside East Harbor areas as sediments are impacted by the former North Beach and Fillmore MGPs. Work is being carried out under oversight of the Water Board and in partnership with San Francisco Recreation and Park Department (RPD). As part of this remediation, the East Harbor area will be updated based on an RPD design.

Learn more on RPD’s Marina improvement and remediation project page.

San Francisco Beach Street (Uplands) MGP

The former Beach Street MGP operated near the intersection of Beach and Powell Streets in the Fisherman’s Wharf area of San Francisco. The plant was built between 1899 and 1900, and PG&E acquired it in 1911. The plant produced gas for PG&E’s customers until approximately 1931 when it was closed. The gas holder and oil tanks continued to operate at the site until the mid-1950s when the property was sold and redeveloped for commercial use.

A hotel and commercial businesses currently occupy the property. PG&E worked with the property owners under the oversight of the DTSC to conduct soil vapor sampling at the hotel in 2014. DTSC confirmed that sampling results showed there is no health concern for occupants of the hotel or commercial businesses as a result of past site activities, including MGP operations.

In 2007, the San Francisco Department of Public Health issued a letter of certification. It certifies that the soil management reports and the deed restriction on the site satisfy the requirements for the characterization and mitigation of hazardous substances in soil and groundwater.

San Francisco Beach Street (Sediments) MGP

Under the oversight of the Water Board, and in partnership with the Port of San Francisco, PG&E is planning to dredge impacted sediments from historic operations of the former nearby Beach Street MGP between the East Marina adjacent to Pier 39 and Pier 43½. The former MGP operated near the intersection of Beach and Powell Streets in San Francisco.

Learn more in this Water Board fact sheet (PDF)

It is important to note that health experts, toxicologists and our investigation work have found that PG&E's MGP sites generally do not pose a health risk to surrounding communities. This is because residues, in most cases, are located below protective coverings of fill, sediment, asphalt or concrete. 

As the gas plants were historically located near the center of commerce, many of our sites are in downtown areas. Some are in residential neighborhoods. Before site work begins, PG&E and regulatory agencies, the Water Board and DTSC, meet with nearby residents, businesses and community leaders to:

• Discuss work plans
• Address any concerns they may have

We continue this dialogue throughout the entire life cycle of the project. We use work notices, emails, meetings and door-to-door outreach to keep customers informed of our progress.

Measures are put in place during remediation to reduce impacts related to noise, dust, odors, vibrations and traffic on nearby homes and businesses. This includes:

• Air monitoring
• Using measures such as water and plastic tarps to control dust
• Installing noise barriers to reduce construction noise
• Monitoring vibrations and adjusting work efforts as needed
• Limiting work hours to certain days of the week or hours of the day
• Restricting the number of trucks that can drive to and from a work site during a given day

When remediation is complete, we conduct restoration activities to improve the local community and promote public safety. These include planting, landscaping, repairing sidewalks or constructing new parking spaces.