In March, a stranger appeared at scientist Judith Weis’ Manhattan apartment to serve her with legal papers from ExxonMobil. The major producer of plastics chemicals was demanding years of data, drafts, and text messages concerning any research related to microplastics and human health.  

Weis was shocked. A grandmother and marine biologist who retired from her teaching post at Rutgers University more than a decade ago, Weis had only become interested in the evolving study of microplastics’ effect on marine ecosystems and human health as an emeritus professor. She published seven literature reviews suggesting improvements for future microplastics studies, but had never conducted her own hands-on research into the topic.

Weis is one of several scientists caught in the snare of Exxon’s defense against an ongoing lawsuit brought by Sierra Club and three other California environmental nonprofits. The lawsuit, filed in 2024, argues that the oil and petrochemical giant waged a “decades-long campaign asserting that single-use plastics trash is harmless and can be disposed of easily and safely.” 

At least two other scientists affiliated with universities and one research facilitator have also received subpoenas from the company as the case moves through discovery, seeking years of funding details, draft history, markups, corrections, underlying data, and communications around their studies. 

The scientists are not involved in the lawsuit, but their research may be relevant to its outcome. The case cites the proliferation of studies that warn microplastic pollution could pose a widespread threat to human health and the environment — a connection industry lobby groups are working to downplay.

Subpoenas are common in the discovery process of litigation, during which both sides can obtain evidence used to prove their side of the case. But subpoenas can also be a tool to suppress science. For decades, powerful industries have deployed subpoenas against scientists to undermine research that could be used to hold them accountable for harms to public health. 

Some legal experts and scientists say that subpoenas against researchers can disrupt and chill the scientific process when researchers know their unpublished work could be misrepresented. They can also strain scientists’ time, derail their research, and be used to question their integrity. 

Companies are often “looking for what they can glean from huge reams of documents,” including unanalyzed data, drafts, and private communications that can be used to undermine findings, said Lauren Kurtz, executive director of the nonprofit legal advocacy group Climate Science Legal Defense Fund. “The weaponization of subpoenas is a real problem.”

Exxon’s stake in the future of microplastic science

Exxon and other oil and gas giants have bet on plastics as a primary market for fossil fuel products in the future. The industry’s unchecked growth has led to plastic waste found in remote glaciers, the depths of the ocean, and throughout the human body — prompting an outcry to limit plastic production that has been met with fierce resistance by industry.

The dangers of plastic chemicals themselves are well-established: more than 4,200 chemical additives in plastics pose risks to human health and the environment, according to a major peer-reviewed study published in the journal Nature. Studies suggest that microplastics can carry hazardous chemicals into the body, disrupt the endocrine system, and increase the risk of disease. New research from scientists at Columbia University shows that when exposed to water, microplastics release highly reactive chemicals that can contribute to biological damage. 

Exxon is deploying subpoenas against scientists to unearth “criticisms, shortcomings or limitations” related to microplastics research.

As the research on microplastics develops, scientists have debated  how best to detect microplastic particles and their health effects.

Weis’ literature reviews identified gaps in earlier research, suggesting that studies should use materials that more realistically replicate the size and shape of microplastics found in the environment, and that standardized approaches to collecting samples are needed. Her latest review found that microplastics should be considered “toxic pollutants” because of how they can carry toxic chemicals into the body, creating “harmful effects observed on biological processes.” 

“Initial research on anything takes time to develop the best kinds of lab techniques, but that doesn’t invalidate the field and it doesn’t mean there’s not a problem,” Weis said. “I was critiquing not to say ‘this is invalid,’ but to try to improve it.”

Though plastics industry lobby groups like the American Chemistry Council (ACC) say they support “sound science” on microplastics, they are working to emphasize uncertainty and oppose monitoring, stating that there “is no conclusive evidence microplastics are harmful to human health.” The industry is now planning public messaging campaigns to stave off potential regulation, according to Plastics News. 

This summer, the ACC pushed the EPA to delay monitoring of microplastics in drinking water despite appearing to publicly back the effort, citing “substantial scientific and analytical uncertainties.” The EPA shelved its plan to monitor for the particles less than a month later. 

Along with policy threats, Exxon is also fending off lawsuits. In addition to the environmental nonprofits’ case, Exxon faces a similar lawsuit brought in 2024 by California Attorney General Rob Bonta, arguing the company misled the public about the effectiveness of plastic recycling and should pay for the harm of plastic pollution, including the “microplastics pollution crisis.” 

Documents uncovered through a new LA Times investigation reveal that plastics industry scientists have known and been concerned about how microplastics could move throughout the body for at least half a century.

It’s in this context Exxon is deploying subpoenas against scientists to unearth “criticisms, shortcomings or limitations” related to microplastics research, our review of documents found. 

To respond to the subpoena, Weis had to hire her own lawyer after Rutgers declined to represent her. Weis said most of the request was for data and documents she did not have. In June, she handed over her published articles on the topic. 

Mark Gold, the executive director of a state marine research program, also received a subpoena from Exxon. As former deputy secretary of Ocean and Coastal Policy for the California Natural Resources Agency, Gold led and approved the state’s landmark strategy to address microplastic pollution. Gold said legal counsel pointed Exxon’s lawyers to the state for documents no longer in his possession.

The other targets of Exxon’s subpoenas include at least two scientists at U.S. universities leading studies into the links between plastics and human health, who have advocated for stronger regulations. The scientists did not respond to requests for comment, and they are being kept anonymous here because of the potential consequences for their work. Their two universities declined to comment on the status of the subpoenas.

Exxon's law firm on the case, Weil, Gotshal & Manges, did not respond to a request for comment.

When the tobacco industry began to see science that could lead to lawsuits and regulation, it leveraged similar tactics to stymie and dispute that science, said Megan Wolff, a public health historian and the executive director of the Physician and Scientist Network for Advocacy on Plastics and Health. 

“We are where we were in, say, 1952 with tobacco,” after which the product was linked to specific harms in patients, Wolff said. “Tobacco [companies] spent the next 50 years fighting to make sure that was never verified.”

Big Oil and Tobacco have used subpoenas to discredit science 

Trial attorney Joe Rice, who helped lead major litigation against the tobacco, asbestos, and opioid industries, said that while in some cases subpoenas are used legitimately, they are being used more frequently by corporations looking for “a needle in a haystack” to undermine emerging science that links their products to harm. (Rice spoke with us before he died unexpectedly in September.)

In past cases, subpoenas have left scientists with hefty legal bills and professional consequences as they attempt to navigate an often unfamiliar legal system and scrutiny over their unpublished work. 

Subpoenas can cause scientists to “feel bullied and scared,” and ward them off from pursuing certain lines of research, said Wendy Wagner, University of Texas at Austin School of Law professor and co-author of the book “Bending Science: How Special Interests Corrupt Public Health Research.” 

The tactic was well-tested by major tobacco companies facing an onslaught of lawsuits accusing them of deceiving the public for decades about the harms of smoking. 

Subpoenas are more frequently being used by corporations looking for “a needle in a haystack” to undermine emerging science that links their products to harm, said the late trial attorney Joe Rice.

In 1992, tobacco giant RJ Reynolds subpoenaed Paul Fischer, the lead scientist on a study examining the effects of the Camel cigarette “Old Joe” advertisements on 6-year-old children, while battling a lawsuit over its marketing practices. Though Fischer had no involvement with the case, the company sought his data, notes, drafts, and the names and telephone numbers of the children involved in his study. 

Fischer hired his own lawyer to fight the subpoena because his employer, the Medical College of Georgia, refused to represent him. RJ Reynolds’ subpoena was eventually quashed, but then the company filed an open records request for the same documents with the children's names redacted, and Fischer’s employer threatened him with suspension if he did not turn them over. 

After spending about $35,000 on legal fees, turning over his documents, and being branded a “rabid anti-tobacco zealot” by the company’s lawyers, Fischer resigned and opened a family medical practice in Georgia. 

Other targets of RJ Reynolds and Philip Morris subpoenas had to handle similar fallout. A subpoenaed letter from another “Old Joe” study author, Joseph DiFranza, was fuel for a fraud complaint that was eventually cleared by his university. The attacks diverted time from his research and “for a while, I couldn’t sleep,” DiFranza said.

The companies also attempted to subpoena research underlying a study finding a causal link between lung cancer and secondhand smoke, and in their defense against U.S. Department of Justice litigation, demanded more than 50 years of researchers’ documents and personal files.

Philip Morris executives discussed in internal meetings and documents how “the acquisition of data is a major goal” because it would help them “reopen” the debate about whether secondhand smoke was harmful.

Companies have also used subpoenas to discourage scientists from participating as expert witnesses in lawsuits and “put sand in the gears” of accountability, said Robert Proctor, a Stanford professor studying the history of scientific controversy. Proctor was subpoenaed by RJ Reynolds for an unfinished book manuscript while testifying on behalf of smokers suing the company, and successfully fought off the demands. He continued to testify against the industry, which is not always the case for scientists targeted with subpoenas. When the paint company Sherwin-Williams subpoenaed epidemiologist Kim Dietrich for decades’ worth of his and other scientists’ raw data, Dietrich stepped down from serving as an expert witness in cases over the health hazards of lead paint to children.

“If used abusively, there's a chance that you're going to sucker a scientist into complying."

Major oil and gas companies took up the strategy during legal battles over oil spills. While fighting lawsuits over the Exxon Valdez disaster in Alaska, Exxon subpoenaed independent researchers studying the social and mental health consequences of the spill in local communities. One researcher wrote that the demands derailed his research and added significant distress for his survey participants after they found out from local newspapers that the company was fighting for access to their personal information. 

BP also used subpoenas to obtain about 50,000 pages of notes and data and 3,000 emails from scientists studying the Deepwater Horizon oil spill after the oil giant was sued by the U.S. government. 

A similar dynamic is playing out through open records requests against climate scientists.  Conservative groups have filed at least 100 requests at 19 public universities for emails, drafts, and other documents from scientists, to be used to “discredit” climate attribution science in ongoing lawsuits against major oil and gas companies, according to Politico and Nature.

University of Pennsylvania climate scientist Michael Mann was subject to years of expansive information gathering efforts by those who opposed his work, including attempted subpoenas and open records requests, following a campaign by conservative bloggers accusing him of falsifying data. Like the demands targeting scientists now, those efforts boil down to a strategy to malign research and intimidate the scientific community, he said.

“The fringe benefit is to serve notice to other researchers in this field: Look out, we might come for you too,” Mann said. 

Scientists have limited opportunities to fight back against subpoenas 

There are existing federal rules that can help scientists quash or modify subpoenas if a court determines that they would be subjected to an “undue burden” or if the subpoena would require them to disclose confidential information. How those rules are interpreted in a specific case will depend on the judge, said Richard Marcus, an emeritus law professor and litigation expert at UC Law San Francisco.

Some experts say that the courts are well-prepared to prevent abuse of the system. “The defendants are going to be looking for any possible weakness, they will do the best they can to cherry pick — and that’s their job if they can do it [in litigation],” said Richard Daynard, a law professor and president of the Public Health Advocacy Institute at Northeastern University. “Courts are likely to be sensitive to demonstrations that the real motivation is harassment.”

Judges have at times been skeptical of a company’s justification, such as in a 2023 ruling to quash a subpoena from herbicide manufacturer Syngenta against a neurologist whose research linked Paraquat to Parkinson’s Disease. The judge rejected Syngenta’s demand for the “internal deliberative process” of a neurologist who was not involved in lawsuits against the company.

“They are harassing scientists for doing their job.”

But there are still consequences even when subpoenas are defeated. 

Wagner, at the University of Texas School of Law, argued that the existing system does not adequately protect scientists from subpoenas before they reach the courtroom. Universities worried about the political environment “may not always come to the aid of scientists” who receive subpoenas, she noted in her book.

“If used abusively, there's a chance that you're going to sucker a scientist into complying because they don't know any better and they don't want to hire a lawyer,” she said. “Courts are usually pretty receptive [to scientists], but what type of damage is it doing in the meantime?” 

Weis said that because of Exxon’s subpoena she has decided not to submit a new literature review on microplastics to a journal, out of fear that it would invite further legal complications. 

Still, Weis knows she faced less difficulty than others. As a retired professor who only recently turned to microplastics and didn’t conduct original research, she was in a unique position to respond to her subpoena relatively quickly, and to speak out.

“I’m a very minor player in this field — I had no data, no statistics because they were review articles. It’s a lot more difficult if you do,” she said. “They are harassing scientists for doing their job.”

Correction: This piece earlier stated that ExxonMobil was the largest producer of single-use plastics. The text has been corrected to reflect that Exxon is the world's largest producer of polymers used to create single-use plastics.