The global plastics treaty being negotiated this month in Ottawa epitomizes how people’s relationship with these valuable yet problematic materials is changing for the better. If it can be agreed on this year — as I hope it will — this treaty could end plastic pollution and lead to healthier societies. It could reduce the world’s reliance on fossil fuels and short-lived products. And it could lower people’s and nature’s exposures to hazardous chemicals and nano- and microplastics released by the 460 million tonnes of plastic produced globally each year (see go.nature.com/4auwzap).

These negotiations also mark a shift in public attitudes towards plastics — from enabling modernity to being a hallmark of the Anthropocene. These materials contribute to the triple planetary crisis of climate change, biodiversity loss and pollution. And research — including my own — shows that plastics damage the health of both ecosystems and humans, by disrupting hormones, for example (see go.nature.com/4cqt8pj).

The widespread support for the treaty is also striking. It comes from not only researchers, but also the public, civil society and businesses — “all the stars are aligned”, as one of my colleagues says. Swayed by scientists’ warnings and emboldened by public opinion, policymakers are willing to embark on this journey to end plastic pollution.

In reality, however, not all stars are in alignment. Just as in global climate negotiations, countries and companies with vested interests are putting the treaty’s success at risk. The many nations striving for an ambitious treaty are being held hostage by those few that are locked politically and economically in a harmful plastics past. Reining in these vested interests is the key to unlocking a brighter plastics future.

Resistance is coming from countries, such as Saudi Arabia and Russia, that depend on keeping fossil fuels flowing. They have obstructed constructive dialogue and are using delay tactics, such as lengthy discussions about procedural matters. One such debate revolves around whether the plastics treaty should be agreed on by consensus or through a majority vote. If consensus will be required, a single country could veto the treaty and prevent all the others from jointly addressing the problem.

Corporations and representatives of fossil-fuel, chemical and plastics industries have similar vested interests. For instance, four times as many industry lobbyists as independent scientists had registered to attend last November’s round of negotiations in Nairobi. But such lobbyists operate more clandestinely than do researchers, through strategies decided in private boardrooms.

On past form, it seems likely that some lobbyists will try to cast doubt on plastics research to slow down the negotiations. Artificially increasing the scientific uncertainty around tobacco’s adverse impacts on the climate has proved highly effective in delaying policy actions against such products, for example. Doubt, disguised as scientific critique, is cast by discrediting scientists and their research. Meanwhile, companies promote their own studies, which demonstrate a lack of harmful effects.

In my opinion, the problem runs deeper still. I’m concerned that corporations are trying to control the scientific narrative by ‘domesticating’ the community. They create and support meetings, research projects and learned societies to ostensibly ‘support science’, while redefining it.

For instance, in many industries, companies have long promoted the idea that polluting nature is acceptable until risk assessments show otherwise. Although this is an ethical rather than a scientific question, such reasoning allows potentially harmful products to remain on the market. In the treaty discussions, lobbyists will demand risk assessments to demonstrate plastics’ impacts on human health before taking action, work that would take decades to do.

Bringing round fossil-fuel-dependent countries is a challenge for international diplomacy. But it is also crucial that nations take steps to limit corporate influences on the plastics treaty, particularly around the science. Here’s how.

Strong competing-interest rules should be applied to all scientific matters. Participants in the treaty’s negotiation and implementation should be required to report any links to the fossil-fuel, chemical or plastics industries. Making such declarations public would enable scrutiny and accountability. The United Nations could support a mechanism to verify declarations, for instance.

Policymakers should also insulate scientific bodies from corporate interference. Business views should pertain to developing solutions, not debating the science. And the two discussion streams should be kept separate. There is a precedent: the World Health Organization’s Framework Convention on Tobacco Control excludes from its work all experts with links to the tobacco industry. Such a rule does not prevent dialogues between science and stakeholders.

I acknowledge that the private sector is not monolithic and comprises actors who want to contribute to a better plastics future, by supporting the Business Coalition for a Global Plastics Treaty, for instance. But the private sector must build trust by ceasing activities that intend to manufacture doubt. Resources would be better spent on innovating sustainable plastic materials and products.

Thus, state and corporate interests must be reined in for the plastics treaty to be successful, benefiting nature, human health and businesses alike.