California’s Central Coast Regional Water Quality Control Board has approved a Voluntary Cleanup and Abatement Agreement to address per- and polyfluoroalkyl substances (PFAS) contamination around the San Luis Obispo airport.
The agreement is with San Luis Obispo County and the California Department of Forestry and Fire Protection (CAL FIRE) to address PFAS contamination at the airport resulting from the use of firefighting equipment during training and operational activities.
PFAS are a large group of man-made substances that persist in the environment and, at unsafe levels, can affect human health.
This cleanup action arises from a statewide investigative order issued by the State Water Resources Control Board in 2019. Consequently, this is the first time an agreement requiring clean-up and abatement of PFAS contamination in groundwater has been ratified by a regional board in California.
Following the State Water Board’s order, the county cooperated with the Central Coast Water Board to test for the presence of PFAS in soil and groundwater in an area southwest of the airport. Results indicate that PFAS exceeded drinking water response levels in at least 57 wells, including one agricultural well. The regional board then carried out its own investigation into the contamination.
“After much deliberative work by the cleanup and advisory teams, along with input from the public, the Central Coast Water Board unanimously supports the agreement with the county and CAL FIRE, which will ensure that the affected community near the airport has safe drinking water while a collaborative and expedited cleanup takes place,” said Jane Gray, chair of the board. “I also want to acknowledge and appreciate the cooperation of the county and CAL FIRE in constructing an agreement focused on long- term solutions. Going forward, the board will work diligently to ensure the agreement is effectively implemented to provide replacement water, complete investigation activities, and remediate the pollution.”
Per the agreement’s terms, CAL FIRE and the county voluntarily agreed to complete evaluation, groundwater monitoring and remediation activities in two phases and committed to providing point-of-use treatment for affected well users. They also agreed to work with partners to evaluate long-term safe drinking water solutions for the affected community.
If no solutions prove feasible, they are to install well-head treatment on all supply wells impacted by airport-related PFAS within four years. This agreement sets forth cleanup and water replacement requirements in lieu of a cleanup and abatement order.
Per the agreement, the board, the county and CAL FIRE must develop a Public Outreach Plan within 45 days and must present a remediation plan to the board within 120 days. The agreement terminates on June 30, 2026. At that time, a successor agreement may be ratified, or the board may consider issuing a cleanup and abatement order to implement additional actions.
The State Water Board first ordered airports in California to investigate the presence of PFAS in soil and groundwater in 2019, after discovering the link between PFAS and a certain type of suppressant used to put out fuel fires. The investigations confirmed that the highest detections of PFAS at airports are connected with releases of aqueous film- forming foam fire suppressants during training or firefighting operations. The suppressants are fluorinated foams that contain diverse mixtures of PFAS.
The Federal Aviation Administration requires that firefighters conduct periodic performance testing of all fire suppressant equipment, such as spray nozzles on fire trucks. This testing caused PFAS to be released into the environment near the San Luis Obispo airport. After 2019, CAL FIRE modified practices to ensure that the foams are contained when equipment testing occurs.