GRAND RAPIDS, Mich. (WOOD) — The Michigan Department of Environment, Great Lakes and Energy has established water quality standards for two more PFAS compounds: Perfluorohexanesulfonic acid (PFHxS) and perfluorononanoic acid (PFNA).

EGLE set the drinking standard for PFHxS at 59 parts per trillion and 19 ppt for PFNA. In a statement, EGLE officials said municipal water systems will be held to even tighter standards.

The two new standards bring the state’s total to five. There are already standards for three of the most common forms of PFAS: Perfluorooctane sulfonic acid (PFOS), Perfluorooctanoic Acid (PFOA) and Perfluorobutane sulfonate (PFBS).

EGLE is still working on the standards for how much PFHxS and PFNA contamination constitutes an environmental hazard.

PFAS — or per- and polyfluoroalkyl substances — are a large group of compounds first developed in the 1940s and incorporated into all sorts of products for waterproofing and heat resistance. Decades later, research showed that PFAS compounds take a long time to break down organically and can build up in the human body, causing serious health problems including cancer.

According to the National Institute of Environmental Health Services, there are more than 15,000 known PFAS compounds.

EGLE officials said the department will continue to monitor the Environmental Protection Agency’s actions and those of other state agencies. EGLE expects to issue standards for other PFAS compounds in the future and says current standards could be revised “as the science and understanding of PFAS continues to evolve.”