GEOFF BENNETT: The Environmental Protection Agency has, for the first time ever, said that so-called forever chemicals, which are harmful to human health, must be removed from U.S. drinking water.

As William Brangham explains, it's a moment that public health advocates have long called for.

WILLIAM BRANGHAM: Geoff, the head of the EPA, Michael Regan, said these new rules could be -- quote -- "life-changing."

The agency will require municipal water suppliers to virtually eliminate six different chemicals that are currently in the water 100 million Americans drink every single day.

They're collectively known as PFAS, and they have been linked to severe health problems, including certain cancers and birth complications.

According to the CDC, nearly all Americans have measurable amounts of PFAS in their blood today.

So, for a closer look at this, we are joined by Melanie Benesh.

She is vice president of government affairs for the Environmental Working Group, which is one of the organizations that has been pressing for this for years.

Welcome.

MELANIE BENESH, Vice President for Government Affairs, Environmental Working Group: So nice to be here.

WILLIAM BRANGHAM: These chemicals have been around for a very, very long time, and I was looking up at the list of all the different things they are in, pizza boxes, nonstick pans.

They make our clothes and furniture more steam-resistant, but they also can get out and make us sick.

So how big of a move do you think this is from the EPA today?

MELANIE BENESH: This is a consequential, historic, monumental decision from the EPA.

This is probably the most consequential decision the EPA has made with regards to drinking water in a generation.

It's really hard to overstate the importance and the impact of this rule.

PFAS are incredibly ubiquitous.

The contamination in the United States is incredibly pervasive.

And this is the single most efficient way that the EPA can reduce our exposure to these toxic chemicals.

WILLIAM BRANGHAM: So, I mentioned Michael Regan seems to think that this could change people's lives.

You clearly seem to believe the health implications here are enormous.

MELANIE BENESH: It's hard to overstate, in fact, how significant the impacts are on public health.

Not only is this a life-changing regulation.

This is really a lifesaving regulation.

Because of these new rules, people will be exposed to significantly lower amounts of PFAS.

And, as a result of that, thousands of lives will be saved, and there will be tens of thousand fewer cases of serious illnesses, like heart attacks, strokes, bladder cancer, cardiovascular disease, reproductive harms like preeclampsia and infant deaths from low birth weights, immune effects, hypertension, and the list goes on and on and on.

So this is really an incredibly consequential, lifesaving decision by the EPA today.

WILLIAM BRANGHAM: Given that there are thousands of PFAS chemicals, do you have a sense as to why it took the EPA this long?

And of those thousands, why did they just pick these six to come out of the water?

MELANIE BENESH: Yes, so PFAS chemicals have been around for a long time, and the chemical companies manufacturing these chemicals have been dumping them into the water of Americans for decades.

So Americans have been drinking contaminated water for decades, and that's because the manufacturers of these chemicals lied.

They didn't tell their workers, they didn't tell the regulators, they didn't tell the EPA, they didn't tell the nearby communities, they didn't tell anyone about the risks of these chemicals, which allowed them to get away with evading environmental regulation for decades, until this EPA finally stepped in to regulate these six PFAS chemicals.

And even though this is only six of the potentially thousands of PFAS chemicals, what's really smart about this regulation is, it is targeting six of the best-studied PFAS.

WILLIAM BRANGHAM: These are the ones we know the clearest effects of.

MELANIE BENESH: These are the ones that we know the most about.

But, also, the regulation is crafted in such a way that it addresses them as a mixture, and it addresses a combination of PFAS chemicals that ensures that these steps that utilities will have to take to comply, be it seeking out alternative sources of water or installing filtration technology, will effectively treat for the whole class of PFAS.

And so even though the regulation is only targeting these six, when you filter them out, they're not going to just filter those six.

They're going to get much more of the class of the PFAS chemicals and actually other contaminants.

WILLIAM BRANGHAM: Municipal water suppliers have strongly come out against this.

They say this is going to cost a fortune.

I mean, the EPA estimates it could cost $1.5 billion per year to do this.

The industry says it's going to cost way more than that and that it will be costs that fall on consumers, including communities that may not be able to afford this.

What is your response to that?

MELANIE BENESH: I think what's really important is to think about the cost of not taking action.

The EPA has also calculated $1.5 billion in public health benefits,.

And that comes in the form of fewer cases of bladder cancer, fewer cases of hypertension, fewer heart attacks, fewer strokes, fewer infant deaths from low birth weights.

And so the cost of not taking action is more people getting sick and ultimately more people losing their lives.

And so, for decades, the public has been bearing the cost of exposure to these chemicals in the form of illness, in the form of medical cost, in the form of social cost and anxiety around being exposed to these chemicals and watching their friends and family get sick.

And so I don't want that to get lost in the conversation around cost.

For the utilities that will need to take action to upgrade their systems, there are resources available.

Congress has already provided $10 billion in infrastructure funding that can be used to help water utilities filter out these chemicals.

Some of that money is targeted to small, rural and disadvantaged communities.

The EPA is also making funds available to private well owners, which are typically not covered by drinking water regulations.

And water utilities have been successfully bringing private litigation against chemical manufacturers like 3M and DuPont and have been getting, recuperating some of their costs through legal settlements.

And so the resources will come.

But what is really important is to acknowledge the tremendous cost that comes from not taking action and how important it is that the EPA is now finally taking action, because the results of that action will be lives saved.

WILLIAM BRANGHAM: Melanie Benesh of the Environmental Working Group, thank you so much for being here.

MELANIE BENESH: Thank you.