9 lessons from our investigation into 3M Forever Chemicals — ProPublica

After years of covering forever chemicals, ProPublica reporter Sharon Lerner was still nagging at one question. She knew that a handful of 3M scientists and lawyers had discovered in the 1970s that the chemical PFOS had entered the blood of people across the country, and that company experiments at the time had shown that PFOS was toxic. But the company continued to produce the compound until 2000. How, she wondered, had 3M been able to keep its dark secret for decades? For years, no one who knew what was going on at the company had spoken publicly about it. Then last year, a former 3M chemist reached out to Lerner. Here are nine takeaways from the investigation, published by ProPublica and The New Yorker.

In the late 1990s, a 3M scientist found the company’s forever toxic chemicals in nearly every human blood sample she analyzed.

In the late 1990s, 3M chemist Kris Hansen tested samples from dozens of blood banks across the country and found PFOS in every sample. For decades, the company had used chemicals that break down into PFOS in its best-selling fabric coating, Scotchgard, and in a greaseproof coating for food packaging. The company also sold PFOS and firefighting foam that contained it. The only blood that didn’t contain PFOS, Hansen said, had either been collected before 3M began selling those products or in rural areas of China, where items containing fluorochemicals weren’t widely available.

When superiors at 3M learned of Hansen’s findings, they repeatedly questioned her work.

Hansen said her managers tried to convince her that there was something wrong with the tests. Some suggested her equipment was falsified. Rather than accept her results, they bought more scientific equipment – machines that each cost more than a car – and even had Hansen repeat her tests in the manufacturer’s offices. Her managers’ skepticism sometimes made Hansen doubt her own work.

Hansen discovered that she was not the first 3M scientist to find one of the company’s fluorochemicals in human blood, and that the company had kept the discovery secret.

In the late 1990s, Hansen learned that two academic researchers had contacted 3M more than two decades earlier. They had found a fluorochemical in human blood and wondered if Scotchgard might be the source. A 3M scientist named Richard Newmark confirmed their suspicions, but Newmark told Hansen that 3M lawyers had pressured his lab not to admit it, according to notes Hansen took at a meeting with Newmark.

The opportunity to present their results to 3M’s CEO did not go as planned.

In 1999, Hansen was invited to present her PFOS research to 3M’s top executives, including CEO Livio D. DeSimone. She said she was immediately bombarded with skeptical questions from those in attendance: Why did she conduct this research? Who told her to do it? Who did she share the results with? DeSimone appeared to fall asleep during her presentation, she said.

Soon after, she learned that her job was about to change: Another scientist would lead 3M’s PFOS research, she recalled her boss telling her. She was to spend most of her time analyzing samples for other scientists and not ask questions about the results. She felt like she was being punished for that.

When 3M announced to the public that fluorochemicals had been found in blood bank samples, company management downplayed the risks.

The company’s chief medical officer told the New York Times in May 2000 that the chemical’s presence in human blood “does not pose a health problem and will not pose one in the future.” 3M stopped producing PFOS in 2002, but replaced it with PFBS, another chemical that persists in the environment and accumulates in the human body.

The company failed to disclose that experiments conducted in the 1970s had shown that PFOS was toxic.

What Hansen’s bosses didn’t tell her or the public was that 3M had conducted animal tests on PFOS in the 1970s and that those tests had shown that PFOS was toxic. The results remained secret, even to many inside the company. In one animal study, 3M scientists found that a relatively low daily dose of PFOS (4.5 milligrams per kilogram of body weight) could kill a monkey within a few weeks. Although that daily dose was several times higher than the amount an average human would consume, the results show that the chemical currently falls into the highest of the five toxicity levels recognized by the United Nations.

Lerner identified another 3M scientist, Hansen’s former boss, who said he confirmed the presence of PFOS in the population’s blood in the 1970s.

Jim Johnson, Hansen’s former boss, said in an interview that he knew “within 20 minutes” that PFOS does not break down in nature and that he identified the chemical in the 1970s in a sample he received from a blood bank. He also noted then that the chemical binds to proteins in the body and accumulates as a result, and found it in the livers of animals exposed to the company’s products. Yet he did not share that information with Hansen before giving her the assignment that led her to find PFOS in people’s blood nearly 20 years later. Johnson told Lerner he knew Hansen would discover and thoroughly document the presence of PFOS in people’s blood. “It was about time,” he said.

The EPA has begun to address the ubiquity of these toxic chemicals.

In April, the U.S. Environmental Protection Agency set limits for six chemicals, including PFOS and PFBS. The agency noted that PFOS “probably causes cancer” and that no concentration of the chemical is considered safe.

3M produced tens of millions of pounds of PFOS and compounds that break down in it after learning that PFOS is toxic and accumulates in humans. In 2022, 3M said it would stop producing the broader group of chemicals known as PFAS and “work to phase out the use of PFAS across its entire product portfolio” by the end of 2025. (PFOS and PFBS are PFAS compounds.) In a written statement, a 3M spokesperson said the company “proactively manages PFAS” and that its handling of the chemicals has evolved along with “the science and technology of PFAS, societal and regulatory expectations, and our expectations of ourselves.”

“We are damaging public health on an incredibly large scale.”

Recent studies have linked PFAS to an increased risk of certain cancers, developmental disorders in children, reduced immune function, hormone disruption and other health effects. According to the Centers for Disease Control and Prevention, virtually everyone now has at least one PFAS compound in their blood. Because of their ubiquity, “these chemicals pose an incredibly large threat to public health,” said an environmental chemist at Harvard University.

Read the full investigation into how 3M executives convinced a scientist that the dangerous chemicals she found in human blood samples were safe.