PG&E’s manufactured gas plant program

History of manufactured gas plants

San Francisco Manufactured gas Plant

In the mid-1800s and early 1900s, before natural gas was available as an energy source, 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, revolutionizing street lighting, enhancing public safety and enabling businesses to work into the night.

In addition to gas, MGPs produced a variety of byproducts, some of which were useful and marketable, such as 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 MGP sites in PG&E’s service area were no longer needed and were closed down. As was common practice at the time, byproducts of the gas-making process were left buried on-site.

PG&E manufactured gas plant program

In the 1980s, the United States Environmental Protection Agency (EPA) conducted research that identified more than fifteen hundred former manufactured gas plants around the country. The research found that, in some cases, residues from these facilities may remain on-site.

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

To date, PG&E has identified 42 MGPs we formerly owned or operated. As part of our commitment to environmental responsibility, we are working to ensure that any potential impacts to the environment from these MGPs are addressed in accordance with today’s regulatory standards. When DTSC or its sister agency, the Water Board, determine that remediation activities are necessary, we work closely with the 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, from investigation to active cleanup to post remediation monitoring and project completion.

It is important to note that health experts, toxicologists and our investigation work have found that PG&E’s MGP sites do not pose a health risk to on-site users or the surrounding communities. This is because residues, in most cases, are located below the ground surface.

As part of remediation activities, we restore sites with new asphalt, gravel and concrete improvements. The San Rafael site (left) and San Luis Obispo site (right) were restored to prepare the sites for future redevelopment activities.

Commitment to our customers

Because these gas plants were historically located near the center of commerce, many of our sites are located in downtown areas, and some in residential neighborhoods. Before site work begins, PG&E and DTSC meet with nearby residents, businesses and community leaders to discuss work plans and address any concerns they may have. We continue this dialogue throughout the life of the project, and use work notices, emails, meetings, door-to-door outreach and the web to keep customers informed of progress at the site.

PG&E hires locally whenever possible during remediation work. For the Oroville MGP project, three local hires worked as safety flaggers.

Measures are put in place during remediation to reduce impacts related to noise, dust, 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, and 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 like planting new landscaping, repairing sidewalks or constructing new parking spaces to improve the local community and promote public safety.