A scientist’s struggle to find the truth behind 3M’s “forever chemicals” problem
May 29, 2024

A scientist’s struggle to find the truth behind 3M’s “forever chemicals” problem

ProPublica reporter Sharon Lerner explains how manufacturer 3M kept the dangers of PFAS from the public, through the lens of a former 3M scientist.

Sharon Lerner has been reporting on “forever chemicals” for the better part of a decade. These manmade compounds — known as PFAS for short — resist oil, water and heat, take an incredibly long time to break down in nature, and have been used widely in products like Scotchgard, Teflon and firefighting foam.

Lerner has focused part of her work on understanding the flow of information inside manufacturers like 3M. By the 1970s, Lerner says, Minnesota-based 3M had established that they were toxic in animals and were accumulating in humans’ bodies.

But who inside 3M knew? And what did they know? Reporting for ProPublica, a nonprofit investigative news site, Lerner got a complicated answer after coming across a former 3M scientist named Kris Hansen.

Marketplace’s Lily Jamali spoke with Lerner about her recent investigation. The following is an edited transcript of their conversation.

Sharon Lerner: Kris was working at 3M for about a year when her boss asked her to kind of look at a problem they had encountered. They had been measuring levels of a chemical called PFOS in their workers’ blood for years. And they had recently farmed that work out to an outside lab. For comparison, they looked at a sample of blood from the general public, which they assumed would be free from PFOS, which was a manmade chemical produced by 3M. And in fact, what they found was that it appeared to be contaminated, the blood of the general public. Her boss, whose name was Jim Johnson, asked Kris to look into it and figure out what was going on.

Lily Jamali: And she, through her tests, is able to show PFOS was in human blood. And interestingly, she doesn’t seem to really believe her own results at first. Meanwhile, those results are not very well received by the company.

Lerner: Right. So when she first gets her results, she tells her boss, this man named Jim Johnson. And he says, this changes everything. It becomes clear after a little while that he has told some of his superiors and Kris begins to get a lot of questioning, a lot of doubt. She’s asked if her machinery is clean, if maybe the bags and tubing that come in contact with the blood could have been responsible for the presence of the chemical, and she’s just generally raked over the coals, questioned and doubted.

Jamali: Right, so she’s pretty marginalized, in her telling of this story. You know, she sort of steps away from this research at a certain point. And for years after that she, it seems like, avoids the subject of forever chemicals entirely. She continues to work at 3M, goes about her business. Why do you think she was so reluctant to talk about it?

Lerner: Well, I think there were a couple of reasons. It was a very traumatic experience, this year she spent, or a little bit more actually, intensively researching this thing that is really kind of overwhelming and devastating, and then being questioned about what she had found and being undermined. And so I think it was on that level, professionally, very upsetting. But I think also, the idea that there is a manmade chemical that is being produced by your employer, and it’s in everyone’s bodies, including your own, is very upsetting. And I think that she was profoundly shaken. And in order to keep working there, which is a decision that I think she questions now, and I think many people in response to the article have questioned, you know, she had to kind of put it away in her mind, and she did for many years.

Jamali: So years go by, and someone ends up sending Kris Hansen a clip from the comedian John Oliver’s show, “Last Week Tonight.” And this is a segment all about forever chemicals from 2021. And in it, he lists the various health effects linked to exposure to them. Can you describe her reaction when she sees this clip?

Lerner: Yeah, so an old professor sent it to her and said, you know, what do you think? And Kris looked at it and said, oh, I’m shocked, but, you know, she was saddened, she said, because there is so many inaccuracies, because she had believed at the time that it wasn’t toxic. She essentially put blinders on and didn’t allow herself to engage with the emerging medical literature that was full of all these examples that John Oliver was citing right there.

Jamali: And so what does she do?

Lerner: So she starts Googling, and she’s finally looking at this thing that she’s essentially put up, you know, on a high shelf and she dives back in and sees that John Oliver was, in fact, correct. And she starts reading about all that’s happened in the years that she’s turned away from the subject and realizes that there’s a lot of evidence that the chemicals are harmful — PFOS in particular, which is what she was studying. And also that her company, her employer, had known a whole lot about it and had not shared it with her or with the public.

Jamali: You know, this story reminded me so much of the scandal around Exxon. We learned in 2015, thanks to reporting from Inside Climate News, that Exxon knew about climate change decades ago, and then actively misinformed the public about it. What was your takeaway reporting this story about how companies deal with information about harmful things that they might be doing or making?

Lerner: Well, I have been reporting on these chemicals for, gosh, almost 10 years now. And so I had actually written a story that the headline was “3M Knew,” in I think it was 2017, because some of the story was already out. You know, we knew that they had evidence of their toxicity in the 1970s, that’s 3M I’m talking about, and that some of the company had been aware that PFOS was in the blood of the general public in the 1970s. I began to think over the years, like, what does that mean, that they knew? Who knew? And what exactly did they know? And how did they keep it from the public? You know, talking to Kris, it just explains so many of these, filled in these gaps that I had. But not all of them, so it showed me that the company had kept this information from its own scientists.

Jamali: And it sounds like Kris and other various scientists within the organization knew bits of the bigger-picture story here, but not the whole story.

Lerner: Well, Kris certainly didn’t know that the chemical was in the blood of the general public. And she did not know that it was toxic. And that was what her own boss had told her. This is not toxic, it doesn’t harm people. And he certainly hadn’t told her that he already knew that it was in the blood [of] the general public.

Jamali: What did 3M have to say about your reporting?

Lerner: That their kind of management of these chemicals has evolved over time, as our understanding of the chemicals has evolved over time and as science has evolved. It’s different from [the] response that they had given me previously, when I’d written about this, which was that they believe that, you know, the levels that people were exposed to don’t cause health problems. They notably did not say that this time.

Jamali: And they continue to produce variants of forever chemicals now, don’t they?

Lerner: Well, 3M has pledged to stop manufacturing chemicals in the PFAS family by the end of 2025. And I was told by the company spokesperson that they’re on track to do that.

Jamali: Back to Kris Hansen. Even though she’s being sidelined at her company for this research, some of her work is making its way to the Environmental Protection Agency. And I want to talk to you about that because just last month, the EPA came out with landmark regulations on getting PFAS out of our drinking water. Have you talked to her about her reaction to seeing those regulations come out?

Lerner: We haven’t much discussed the regulations. It’s great that they are setting limits on drinking water. It’s something that people in affected areas, which is, you know, across the country, have been waiting for this for years. And they’re taking other actions, including making it easier to clean up the chemicals at Superfund sites. But it’s worth noting that the drinking water [regulations] are really for six individual chemicals, and the class contains thousands. And what I’ve been thinking a lot about is how do we prevent companies from doing this again? 3M didn’t share the information that they had about the chemicals’ dangers in a timely way. And theoretically, the law worked here. The company was fined, but they were fined $1.5 million, which is nothing for a company like that. With such a light slap on the wrist for something like that, we can potentially have really important secrets kept from us again in the future, if they’re inconvenient to sales. Companies are not going to be inclined to follow the law on this. And that’s what worries me.

More on this

We reached out to 3M for a response to this segment. The company said it is supporting remediation for U.S. public water suppliers across the country. That includes a multibillion-dollar settlement reached last year. You can read the full statement below:

As the science and technology of PFAS, societal and regulatory expectations, and our expectations of ourselves have evolved, so has how we manage PFAS. We announced in 2000 that we would phase out of manufacturing of PFOA and PFOS and have done so worldwide. After our decision to phase out these compounds and applications, others in the industry eventually followed suit as to certain PFAS.

We are making good progress on our announcement in 2022 that we would exit all PFAS manufacturing. We’ve made major investments in state-of-the-art water treatment technologies, with our $1 billion commitment to deploy these technologies at our chemical manufacturing operations.

We share information about 3M’s products that contain PFAS, as well as updates on our reformulation and innovation efforts, on our website and have done so for several years: We are supporting PFAS remediation for U.S. public water suppliers (PWS) across the country that detect any form of PFAS at any level or may do so in the future through the settlement agreement we announced in 2023.


3M said payments would start going out to many public “drinking water systems” here in the U.S. in the third quarter of this year.

As Lerner mentioned, 3M also says it’s progressing toward exiting all PFAS manufacturing by the end of 2025. In its annual report, 3M writes “the Company continues to evaluate whether there may be some circumstances in which the use of PFAS-containing materials manufactured by third parties and used in certain applications in 3M’s product portfolios, such as lithium ion batteries and printed circuit boards widely used in commerce across a variety of industries, may continue beyond 2025.”

We’ve also linked to our recent conversation with a senior scientist at the Environmental Working Group, who told us that there are ways to filter forever chemicals from our drinking water, but we don’t have good methods to dispose of them.

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