With its scenic views, it is hard to imagine the Marina as a patchwork of swamps, cow pastures, and clothes-washing lagoons in the mid- to late-1800s. The Marina was also the location of the two manufactured gas plants (MGPs) that produced gas for lighting, heating and cooking from coal, oil and water.
Now, over 100 years later, measures are being taken to address potentially harmful residue from hydrocarbons that may exist in the footprints of these plants.
Gas manufacturing in San Francisco originated in the Gold Rush era when the city was the key urban and financial center for the U.S. western territories. At least four manufactured gas plants supplied gas for lighting, cooking and heating in the city, with two in the Marina District. One was the Fillmore MGP with its main plant located in the area southwest of Fillmore and Bay Streets, and a secondary site northwest of Chestnut and Buchanan (now covered by Marina Middle School paving).
The Fillmore MGP was in operation from 1883 until it was destroyed in the 1906 earthquake. Kathleen Iudice, publicity director for the San Francisco Museum and Historical Society (SFMHS) points to an account written in 1906 by Edward Jones, a gas engineer for the S.F. Gas and Electric Company, that shows engineers at the time of the earthquake worked diligently to shut off gas from the plant and repair the system.
The second Marina plant was known as the North Beach MPG, located northeast of Bay and Buchanan Streets. This plant started operation in 1891 and was destroyed in the Great Quake as well, according to PG&E, which took over operation of both plants in 1905.
Realtor and SFMHS member Gloria Rogan said that in the early days, much of the Marina District was swampland used as a place to graze cows and wash clothes. According to Rogan and other historical researchers, manufactured gas at that time was produced using a “carburetted water” system, which made gas by passing steam over red-hot carbon fuel. Rogan added that “the real estate maps dating back to 1904 show all the ground water,” and show the Marina District was a desirable location for the MPG plants.
The process produced a lot of waste material, however, some in the form of tars that included cyanides, metals and solvents.
By the end of the 1915 Panama-Pacific International Exposition, the old system of “water-gas” was completely dismantled.
“Of the 41 manufactured gas plant sites historically owned or operated by PG&E through the 1950s, 40 have been or are in the process of being investigated, cleaned up, or remediated,” said Nicole Liebelt, a PG&E spokesperson. “The investigation of the former MGP sites in the Marina District was initiated in 2010.”
The concern about tar residue from manufactured gas has been ongoing for many years. More than 20 years ago, the U.S. Environmental Protection Agency (EPA) conducted research that identified about 1,500 former MGPs around the country. The research found that, in some cases, residues from these facilities might remain onsite. Water contamination is rare, but there is always a danger that tar can cause health hazards, which is why monitoring and testing are important.
Following the EPA study, PG&E and utility companies across the country established a program to identify the location of MGP sites and began testing groundwater and soil samples within the service areas. Liebelt noted, “PG&E wants to ensure that any potential impacts to the environment from former MGPs are addressed in accordance with today’s regulatory standards.”
Liebelt said that one thing that was not stressed in previous reports is that the cooperation of the public is voluntary. Private property owners in the footprint of the MGP sites have already been contacted regarding their participation. Presently, only five property owners have chosen to participate in the cleanup process, which includes temporary relocation if requested.
Soil samples have also been collected from public rights-of-way with the approval of the City and County of San Francisco.
The duration of any tar residue cleanup could be from six weeks to four months. The process could involve soil removal, ranging from very little up to approximately 300 cubic yards. “It’s really dependent upon the site and the residual impacts found on that particular property,” Liebelt said.
Most of the tar residue is within a depth of about three feet. No residue has been found at the surface of any of the property sites tested so far, and officials said they do not expect to find any. Due to the filling and grading that took place after the earthquake, and again following the burning and subsequent demolition of the 1915 Panama-Pacific International Exposition, PG&E says direct contact with any materials left from plant operations is unlikely.
Liebelt emphasized that the cost of cleanup would be paid by PG&E. For more information about the MGPs residue cleanup program, call 415-973-0270, or e-mail email@example.com.