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I'm an engineer. I like to build things that solve problems. So part of me was excited about the recent announcement from the federal Environmental Protection Agency of new drinking water limits for six per- and polyfluoroalkyl substances (PFAS), which will reduce health risks for some Americans. But we need to think about health risks holistically and focus our limited resources on policies and actions that equitably reduce health risks for current and future people.

The majority of Americans get most of their PFAS exposure from food and household dust inhalation, not through drinking water. In addition, we are still making and using a lot of these chemicals. Focusing on PFAS that are already in the environment before we significantly reduce production and emissions is like trying to drain the bathtub before the faucet is turned off.

PFAS — also known as "forever chemicals" — are a broad and very useful class of synthetic chemicals that are found almost everywhere in consumer supply chains. Most have probably heard of the potential human health impacts, including increased risk of cancers and immune dysfunction.

They're known as forever chemicals because they are highly persistent. They don't break down by any known natural process. This means that any PFAS made will ultimately enter the environment unless actively destroyed, and any PFAS entering the environment will stay there indefinitely. PFAS are also very mobile in air and water, which means that they can travel across continents in the atmosphere.

These factors combined mean that removing PFAS from the environment is costly — between $1 and $100 million per pound. For comparison, any consumer can go to a local hardware store and purchase PFAS for around $50 to $1,000 per pound, depending on what products they choose.

If you think of environmental PFAS as a bathtub, the faucet is currently on full blast, with over a million tons produced globally each year. That's enough to contaminate the volume of all oceans on earth to concentrations exceeding the EPA's new drinking water limits within a few years, if all the PFAS mass made were distributed evenly in the Earth's water supplies.

In contrast, the bathtub drain is very small, reflecting limited destruction of PFAS from environmental sources. And it would be very expensive to increase the size of the drain. I recently reviewed emissions and cost data and estimated that it would cost more than the global GDP each year to remove and destroy PFAS from the environment at current emission rates.

If we are worried about environmental PFAS and associated health risks, we cannot afford to make the drain big enough. We need to turn down the tap.

Turning down the tap means phasing most PFAS out of consumer products, which can likely be accomplished within the next decade. Success stories like those from IKEA and Keen Footwear show that we can phase these chemicals out of many consumer products. Most PFAS in consumer products have replacements available now, but companies need to better understand the PFAS in their supply chains as a first step toward phasing them out.

The economic benefit of managing the bathtub at the tap is that costs will primarily be borne as a one-time transition investment rather than ongoing societal cost burdens associated with constantly increasing health care and treatment costs.

Minnesota is a leader in the fight against PFAS. The state recently passed legislation to identify PFAS sources in consumer products and prohibit their use in most products by 2032, and U.S. Rep. Betty McCollum of Minnesota just introduced similar legislation at a federal level. I hope this is a harbinger of broader, global efforts to restrict PFAS use and emissions.

My takeaway is one of hope and a drive for action. We can do nothing, or we can act to reduce PFAS use. If we care about the health of future generations, we literally can't afford to keep making these forever chemicals. Let's make our grandchildren proud on this one.

Ali Ling is an assistant professor of civil engineering at the University of St. Thomas School of Engineering.