Notification Level Recommendation for Perfluorohexanoic Acid (PFHxA) in Drinking Water

Sep 18, 2024

The Office of Environmental Health Hazard Assessment (OEHHA) is recommending that the State Water Resources Control Board (Water Board) establish the notification level (NL) for perfluorohexanoic acid (PFHxA) at 1 part per billion (equivalent to 1 microgram per liter). This recommendation is based on OEHHA’s development of a health-protective concentration intended to prevent noncancer effects, including thyroid, nasal cavity, liver, and developmental toxicity.

PFHxA is a member of a large class of chemicals known as per- and polyfluoroalkyl substances (PFAS) that are used in many consumer products for their non-stick and water-, grease- and stain-resistant properties, and also in firefighting foams. Exposure to PFHxA above certain levels can cause adverse health effects, including harmful effects to the thyroid, the nasal cavity, the liver and the developing fetus. While consumer products are a large source of exposure to these chemicals for most people, drinking water has become an increasing concern due to the persistence and tendency of these chemicals to accumulate in groundwater.

NLs are nonregulatory, health-based advisory levels that the Water Board establishes for contaminants for which regulatory standards have not been set. Certain requirements are triggered when chemicals are detected at levels that exceed their respective NLs.

For more information about PFAS, NLs, and the work the Water Board is doing to assess the presence of these contaminants in drinking water, please visit the Water Board’s website.