High levels of benzene were released into the groundwater in Weld County at the end of December, according to the “Weld County oil and gas spill report for Jan. 6” in The Tribune (Greeley). The article states,
“• KERR MCGEE OIL & GAS ONSHORE LP, reported Dec. 28 a historical tank battery spill about 7 miles northeast of Fort Lupton, near Weld roads 22 and 41. Less than five barrels of oil, condensate and produced water spilled. Waters of the state were impacted. Crews found the impacts while deconstructing the tank battery. A groundwater sample indicated benzene and total xylene concentrations of 358 μg/L and 10,000 μg/L respectively.”
There was no further information in the initial report if these chemicals reached the drinking water aquifers. In response to a Jan. 8 inquiry to the COGCC regarding the impact on the aquifers, the COGCC replied, “Yes, groundwater at the site will be sampled and analyzed as part of a site investigation and remediation plan required by rule when impacts to groundwater are found. A condition of approval related to the initial spill report is to provide a site investigation and remediation plan as part of the spill response. Submission of the site investigation and remediation plan within 90 days of the initial spill report was specified. If you are a landowner in that area and are concerned about the quality of groundwater from your well you could file a complaint regarding those concerns with the COGCC.”
Benzene is a known human carcinogen. One microgram per liter (ug/L) is about 1 part per billion (ppb) which means that there was 358 ppb of benzene in the groundwater due to this spill. Per the American Cancer Society, the EPA limits concentrations of benzene in drinking water to 5 ppb.
This chart from a recent CU Thesis paper shows the the Federal and Colorado maximum contaminant limits for water wells.
According to the National Institutes of Health, the “main effect of inhaling xylene vapor is depression of the central nervous system, with symptoms such as headache, dizziness, nausea and vomiting.”