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. Most of the sites in PG&E’s service area were closed and dismantled more than 75 years ago.
In the 1980s, the United States Environmental Protection Agency 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 onsite.
Following the Environmental Protection Agency (EPA) study, PG&E established a 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 water supplies and soil samples from sites in the service area.
According to toxicologists and health experts, exposure to MGP residues is not common because, in most cases, they are located below the ground surface.
As part of our commitment to environmental responsibility, PG&E works to ensure that any potential impacts to the environment from former MGPs are addressed in accordance with today’s regulatory standards. PG&E is in the process of investigating and remediating forty one MGP sites it formerly owned or operated. They are in various stages of remediation, from investigation to post remediation monitoring and project completion.
Where DTSC determines that remediation activities are necessary, we work closely with the agency, residents and local health and environmental departments to design the most effective remediation program for the site.
This is a voluntary effort that reflects PG&E’s environmental commitment and responsibility to address issues that may have resulted from our historic operations.
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. PG&E works closely with those customers whose homes or businesses may be affected by our work to ensure that any associated impacts are lessened and everyone stays informed about the project throughout its duration.
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, and the web to keep customers informed of progress at the site.
Measures are put in place during remediation to reduce impacts related to noise, dust, and traffic on nearby homes and businesses. This includes air monitoring, installing noise barriers to reduce construction noise, 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 have conducted restoration activities like planting new landscaping, repairing sidewalks or constructing new parking spaces to improve the local community and promote public safety.
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.