The danger of water contamination with perfluoroalkyl and polyfluoroalkyl substances — called PFAS for short and “forever chemicals” informally, because of their persistence in the environment — has been well known for years nationally.

Certainly Hawaii, which has been through a tumultuous time with the tainting of water by the underground Red Hill Fuel Storage Facility leaks, has had a close encounter with the issue.

Now, encouragingly, the Environmental Protection Agency has issued hard limits on six of these chemicals in drinking water, limits that will require utilities to reduce them to the lowest level they can be reliably measured. The limits vary, but two of the most concerning forms, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), must be below 4 parts per trillion.

Fortunately, the Honolulu Board of Water Supply — Hawaii’s utility that has been most directly drawn into the PFAS debate because of the Red Hill contamination crisis — is already working with the state Department of Health to see that Oahu meets the standard.

So far, its testing has found the regulated chemicals at eight sites, but at about half the action levels set by the new rules, said Erwin Kawata, the water board’s deputy manager who has headed the agency’s work on PFAS issues. Even so, Kawata added, the board has hired a consultant to help prepare for filtration, should that be required in the future, and will pursue the federal funds available for any needed cleanup.

That’s a relief for now, but there is a need for the entire state to stay on the alert and prepare to take corrective action. There is already an effort across the U.S. Department of Defense to replace stocks of one type of PFAS used in firefighting: aqueous film forming foam. Locally, alarms went off when AFFF spilled from a pipe at Red Hill in November 2022.

Nationally, exposure to “forever chemicals” is widespread, because they’ve been used for years in everything from dental floss to children’s toys. According to a 2020 study by the nonprofit Environmental Working Group, an estimated 200 million Americans had PFAS chemicals in their drinking water.

The potential health impacts are significant. More than a dozen peer-reviewed studies in the past year have found evidence of exposure linked to a delay in the onset of puberty in girls, which then could cause a higher rate of breast cancer, renal disease and thyroid disease. Other long-term risks could include osteoporosis and an increased risk of Type 2 diabetes in women.

On Oahu, fears about public health have raged since November 2021, when a petroleum release from the Red Hill tanks contaminated drinking water wells largely serving military communities. Honolulu water board officials have rightly worried about movements of the contamination elsewhere in Oahu’s aquifer system.

Kawata acknowledged that water treatment for PFAS is expensive — nationally, the annual outlay is estimated at $1 billion — but he said the funds available from the federal Bipartisan Infrastructure Law will make the costs manageable at the local level. The chemicals are considered “emerging contaminants,” so removing them qualifies for the federal funds.

The three detected here are PFOA, PFOS and perfluorohexane sulfonate (PFHxS). They were found at wells in Waipio Gentry, Moanalua, Makakilo, Waipahu, Halawa, Pearl City, Kaamilo and Aina Koa, Kawata said. None pose a problem yet, he said, but if levels rise, the water board wants to be ready to act.

That should be the stance taken throughout a state so dependent on water stores for survival. Anything less than vigilance is simply unacceptable.