"In government records that have flown under the radar, the EPA is questioning its legal authority to revise pollution rules more than once when new science shows unacceptable health risks."

"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."

Lisa Song reports for ProPublica January 7, 2026. [2]