San Luis Obispo County officials Friday reported preliminary samples taken from Regional Airport property tested negative for trichloroethylene, or TCE, a toxic solvent that was found to have contaminated nearby private wells.
The Central Coast Regional Water Quality Control Board required the tests, which were conducted by consulting firm Roux Associates, after 12 private wells in the Buckley Road area had TCE levels that exceeded state thresholds.
The airport was considered the potential source of the contamination because TCE was used as an aircraft solvent until it was phased out in the 1970s because of its toxicity. County officials disagreed, saying airport records showed no evidence the chemical was ever used.
The Water Quality Control Board received preliminary test results throughout the summer; 94 soil-gas samples, which collect vapor from just above the soil, have now been submitted. Groundwater on the airport property has also been tested — all of the samples have tested negative for TCE, according to the report.
The county expects to finish soil-gas and groundwater testing at the airport by Sept. 12. The final soil-gas report will be available on Sept. 20, the groundwater report on Oct. 10.