Mar 21, 2019

Last week, activists posted “Breaking News!” regarding “evidence of groundwater well contamination by oil operations” in the Oxnard Oil Field. Citing a “landmark study” completed by experts with the United States Geological Survey (USGS), the activists with Citizens for Responsible Oil and Gas (CFROG) claimed thermogenic gases had contaminated nearby water wells, and oil operations were to blame.

However, that’s actually not at all what the USGS scientists found. As Celia Z. Rosecrans, the USGS study author, stated in the report: “The results of our sampling found we had no evidence or no detections of petroleum hydrocarbons, inorganic constituents, or isotopes that indicate that we had oil field water mixing with the groundwater overlying the oil field.”

Furthermore, while the USGS did report that thermogenic gases had been detected in deep water wells, their study did not conclude that oil field activity was the cause. Rosecrans explained that detections of naturally-occurring thermogenic gases in deep groundwater could have resulted from natural vertical migration through the geologic formation, or through wells.

Experts have noted that the USGS sampled groundwater at 1,500 feet below the surface, just above hydrocarbon-bearing formations that exist at 2,000 feet below the surface. Given this small separation difference of only 500 feet, experts say it should be no surprise for naturally-occuring thermogenic gases to be found in deep groundwater wells in the Oxnard coastal plain.

Finally, CFROG’s claim of “contamination” is also at odds with the facts. The low level of dissolved gases found in groundwater samples does not exceed any drinking water standards established by California regulatory authorities.

Given these facts, CFROG either fundamentally lacks the expertise to comment on the study, or the group is blatantly misrepresenting USGS findings to smear oil operations and alarm the public.

While it’s unclear how much CFROG actually understands about these issues, one thing is certain: energy policy in Ventura County should be based on facts and science, not twisted misinformation pushed by activist groups.


[SOURCE: Rosecrans, Celia Z., Landon, Matthew K., and McMahon, Peter B., 2019, Groundwater quality results from the Regional Monitoring Program study of the Oxnard Oil Field, presented at California State Water Resources Control Board Stakeholder Meeting, February 25, 2019, Sacramento, California]