On March 21, 2022, the California Office of Environmental Health Hazard Assessment (OEHHA) released a recommended Notification Level (NL) for perfluorohexane sulfonic acid (PFHxS). The recommended NL is 2 parts per trillion (2 ppt), based on a noncancer endpoint (decreased thyroid hormone levels). Copy of OEHHA’s supporting documentation is here: https://wqts.com/wp-content/uploads/2022/06/pfhxsnl031722.pdf