Pictured: Southern California Gas Company natural gas compressor facility on W. Olive St., in Ventura. Google Earth Image.
by Kimberly Rivers
Through Feb. 10, the public is being asked to provide input to the California Department of Toxic Substances Control (DTSC) regarding a plan for protecting human health and the environment related to contaminants at an 8.5-acre site in West Ventura where Southern California Gas Co. (SoCalGas) is planning to update its natural gas compressor facilities.
Contaminants of Potential Concern (COPC) including lead, arsenic, carcinogenic polycyclic aromatic hydrocarbons (cPAHs) and other compounds have been identified in both soil and soil vapor at a site located at 1555 West Olive Street in Ventura, just behind E.P. Foster Elementary School.
The public is being asked to weigh in on the 145-page Removal Action Workplan (RAW), which includes the results of groundwater, soil and vapor testing. Recommendations in the RAW include: excavation of nearly 1,700 cubic yards or 2,500 tons of “shallow soil” determined to contain “carcinogenic PAHs, TPH [total petroleum hydrocarbons], arsenic and lead,” approximately 106 truck trips to transport the contaminated soil for treatment and/or disposal, then another 106 truck trips to bring in clean fill to backfill the excavated site. The plan includes the adoption of an operations plan to “address vapor intrusion risks within the proposed compressor building” that SoCalGas plans to build. Finally, the plan introduces a “Land Use Covenant to prevent residential development or other sensitive uses” at the site.
According to the federal Environmental Protection Agency, PAHs “are a class of chemicals that occur naturally in coal, crude oil and gasoline.” PAHs produced when those compounds are burned “can bind to or form small particles in the air.”
PAHs along with TPH, arsenic and total lead were significant constituents found in shallow soil samples (surface to five feet) at the site. Lead and arsenic were detected above screening levels at two locations.
The report states that “the removal of cPAHs [carcinogenic polycyclic aromatic hydrocarbons] to background levels will ensure that health risks” associated with the southern area of the site “do not pose a greater risk than that posed by ambient concentrations.”
The cleanup plan for the property focuses on contaminants in soil and resulting vapor that are being attributed to the activities of Ventura Manufacturing Gas Plant (MGP), a company that used crude oil to manufacture gas from 1905 to 1919 and finally closed in 1920. For 100 years contaminants from that company’s activities have stayed in the soil and are today being found in the vapor around the soil.
Significant concentrations of TPH were found in deeper soil and state records report those findings “correlate with impacted groundwater from upgradient sources” from two neighborhing parcels.
Indoor air quality risks include naphthalene, “assumed to volatilize to indoor air spaces,” being named as “the largest contributor to risk.” This was related to indoor situations only at the new compressor building being proposed by SoCalGas.
Groundwater investigations at the site used a total of 38 groundwater monitoring wells connected to various parcels at the property. Eight of those wells were included in inquiries related to an underground storage tank investigation, which identified multiple chemicals in the groundwater including benzene, toluene, ethylbenzene and xylenes (BTEX), naphthalene, benzopyrene, methyl tert butyl ether (MTBE), indicators of common motor fuel, trichloroethene and vinyl chloride. Those findings led to an in-situ chemical oxidation groundwater remediation program that was overseen by the Ventura County Resource Management Agency, and reportedly wrapped up in 2013. Significant constituents related to the MGP operations that were found in shallow soil include TPH, arsenic and lead.
Summaries of the proposal describe investigations that occured in February and March 2020, which found “concentrations of some volatile organic compounds in soil vapor samples,” which “exceeded screening levels” at the south area of the site. In response, cleanup plans focus on removing “shallow soil” from the surface to 15 feet that contain Contaminants of Potential Concern (COPC), including lead, arsenic, TPHs and PAHs,” some of which “exceeded residential levels” and thus are “targeted for removal.” The plan is to “remediate to the point that minimizes the need for any future land use restrictions” — meaning that residential uses could be safely allowed because “residual levels” are “below residential” allowable levels.
The studies also found total petroleum hydrocarbons in concentrations at deeper soil depths that “exceed residential” and “industrial” screening levels. In addition, compounds found in soil vapor samples included benzene, chloroform, 1,4- dichlorobenzene, cis-1,2-dichloroethene, ethylbenzene, methyl-tert-butyl ether, naphthalene, tetrachloroethene, trichloroethene, vinyl chloride, xylenes, and TPH-g.
The site is just west of a residential area and the rear boundary of E.P. Foster Elementary School is just across the street from the property. The other areas around the site are mostly industrial-commercial. The Ventura River is just west of Highway 33, which is the eastern boundary of the property.
Before Feb. 10, written comments can be submitted via email to Chand.Sultana@dtsc.ca.gov or postmarked by Feb. 10 and mailed to: Ms. Chand Sultana, PhD., DTSC Project Manager, 9211 Oakdale Avenue, Chatsworth, CA 91311.
The Removal Action Workplan: Ventura RAW_Final Draft 18Dec2020
Link to DTSC page with all documents and project details: https://www.envirostor.dtsc.ca.gov/public/profile_report?global_id=56490101