When the chemical giant DuPont unveiled Teflon in 1946, nonstick pots and pans seemed like a miracle. We now know their coatings contain “forever chemicals,” or PFAS, which don’t break down. These compounds are not only in cookware but in clothing, cosmetics and more — and they contaminate the water millions of us drink.

Research shows there’s no safe level of exposure. With the Environmental Protection Agency rolling out new limits on PFAS in drinking water, Marketplace’s Lily Jamali asked Tasha Stoiber, senior scientist at the Environmental Working Group, about the tech used to filter it. The following is an edited transcript of their conversation.

Tasha Stoiber: There are a number of ways to do it. There’s granular activated carbon, and when you use that for drinking water treatment, the PFAS basically just sticks to that media and you remove PFAS.

Lily Jamali: Is that a thing that you drop into a big pot of water, or a big vat of it? How does that work?

Stoiber: I mean, there’s a number of different types of granular activated carbon. But you can kind of think about it the same way as there’s granular activated filters that you use in your home as well. So it’s just at a different scale when you use it for community water treatment. They’re quite large.

Jamali: I’m picturing a giant Brita right now. Is that basically what you’re saying?

Stoiber: You could think of it as a giant Brita. So at the drinking water treatment level, you have very large granular activated carbon filters that drinking water systems can install. And those are quite effective at removing PFAS. The PFAS stick to those filters, and they’re removed from the water. And there’s a couple of other different ways that you can remove it as well. There are a couple of plants that have installed reverse-osmosis membrane filters, which are filters that have very tiny pores and the chemicals are retained. And then you have clean drinking water on the other side. And then there’s ion exchange, which works to remove PFAS as well. The downside is that from these processes, you do produce waste. For example, the granular activated carbon, it must be regenerated or you have to do something with the spent activated carbon media. Reverse osmosis, you do have a waste stream brine, you have to do something with that. And that is a bigger long-term problem as well, that there are not yet good disposal methods for the media that we use to treat drinking water.

Jamali: It sounds like what you’re saying is, you can remove these forever chemicals, but you can’t yet destroy them — that technology isn’t there yet?

Stoiber: There are ways to do it, but we still need more information about how efficient it is, more information about the products of incomplete combustion that are formed during incineration. Incineration has been happening in practice, but there are a lot of questions about the air pollution that might result from it, or if it is being optimized as much as it can be. And we still don’t know everything that we need to know about when incineration is happening in practice, if there is, in fact, air pollution that is resulting from it. So there are still a lot of questions that need to be answered, and we still don’t yet have good disposal methods.

Jamali: Now, you’ve been focusing a lot of your research on filters for consumers. How do you think filters like that will play a role in all of this for consumers who want to start limiting forever chemicals in their drinking water at home?

Stoiber: Right. So we do recommend that people filter their drinking water at home. Granular activated carbon filters are effective at removing PFAS, reverse-osmosis filters are also effective at removing PFAS, but granular activated carbon filters might be a bit more cost-accessible to people, but you just have to remember to change out the filter, or else it’s not effective.

Jamali: And are you seeing innovation happening among cleantech companies working on water filtration so that people can filter these chemicals out, at least somewhat, at home?

Stoiber: There are more advanced and better countertop filters that are available now that actually are quite effective at removing PFAS from your drinking water. We did a quick, short study of several of these pitcher-type filters. And they were fairly effective at removing a number of different PFAS, which was good news.

Jamali: Yeah, I saw some of them can eliminate up to about half of the forever chemicals that are in the water.

Stoiber: Right, and our tests showed, for the PFAS that we measured, that they were fairly efficient and removed almost all of the PFAS that we tested for. And other researchers have shown, too, that multistage carbon filters work really well also. But people should know that the very simple carbon filters, the Britas and the Brita knockoffs, those types of filters are just rated to remove things like taste and odor and chlorine. They’re not designed to remove much more than that. And those types of filters aren’t that effective at removing something like PFAS.

Jamali: So we’ve been talking so much about the technologies that are available at the industrial level, but also at the consumer level. What should we know about the costs of some of these technologies?

Stoiber: Yeah. I mentioned before, the cost of in-home drinking water filters can vary quite a bit. But overall, in-home drinking water filters might not be in everyone’s budget. And that’s why it’s even more important in the context of EPA’s announcement to finalize the drinking water standards for PFAS so that there is better drinking-water quality for everyone because it definitely isn’t in everyone’s budget to have an in-home water filter to filter these out.

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The EPA’s first-ever limits on PFAS in drinking water announced last week are already being cited in lawsuits. This includes legal action that more than a dozen water utilities in California brought against seven PFAS manufacturers, accusing them of negligence.

Time magazine reports that some of the largest PFAS manufacturers, including DuPont and 3M, had preliminary evidence that forever chemicals were toxic as early as the 1960s. But it wasn’t until the late 1990s that the public heard about their potential dangers, according to a study published last year in the scientific journal Annals of Global Health.

In 1981, female workers at a DuPont chemical plant in Parkersburg, West Virginia, were abruptly moved away from parts of the facility involved in their production without much of an explanation. It turned out that some workers there had given birth to babies with a range of ailments. One had the chemicals in its cord blood, and another was born with eye defects and one nostril. PFAS exposure has been linked to development delays and certain cancers, as well as a host of other conditions.