Honest, paywall-free news is rare. Please support our boldly independent journalism with a donation of any size.

This story was originally published by ProPublica. ProPublica is a Pulitzer Prize-winning investigative newsroom. Sign up for The Big Story newsletter to receive stories like this one in your inbox.

Ethylene oxide was once considered an unremarkable pollutant. The colorless gas seeped from relatively few industrial facilities and commanded little public attention.

All that changed in 2016, when the Environmental Protection Agency completed a study that found the chemical is 30 times more carcinogenic than previously thought.

The agency then spent years updating regulations that protect millions of people who are most exposed to the compound. In 2024, the EPA approved stricter rules that require commercial sterilizers for medical equipment and large chemical plants to slash emissions of ethylene oxide, which causes lymphoma and breast cancer.

It was doing what the EPA has done countless times: revising rules based on new scientific knowledge.

Now, its ability to do that for many air pollutants is under threat.

In government records that have flown under the radar, President Donald Trump’s EPA said it is reconsidering whether the agency had the legal authority to update those rules.

Chemical companies and their trade organizations have argued that the EPA cannot reevaluate hazardous air pollution rules to account for newly discovered harms if it has revised them once already.

It doesn’t matter if decades have passed or new information has emerged.

If the EPA agrees, environmentalists fear that the decision could have wide implications, significantly curbing the EPA’s ability to limit nearly 200 pollutants from thousands of industrial plants. The next time new science reveals that a chemical is much more toxic, or that the amount of pollution released from a factory had been underestimated and would cause legally unacceptable health risks, the agency would not be able to react.

“It’s a poor reflection on this administration’s claim that they are actually interested in clean air,” said Ana Baptista, a professor of environmental policy and sustainability management at The New School. “By saying we’re no longer going to consider science, it’s abdicating your mission.”

The EPA didn’t address ProPublica’s questions about the ethylene oxide reevaluation or its broader implications. Instead, the agency pointed to a March press release about how it was reconsidering multiple air pollution rules issued by President........

© Truthout