A new Trump administration plan to rescind 2024 regulations for toxic ethylene oxide (EtO) pollution more broadly aims to limit the Environmental Protection Agency’s authority to strengthen public health protections around hazardous emissions and could result in more of the toxin being released into the air.

Recent research has found EtO is about 60 times more carcinogenic than thought when the last regulations were developed in 2006. In 2024, the Biden EPA passed a rule that strengthened the regulations to reflect the updated science, and required the nation’s EtO emitters to collectively cut their emissions by about 90%.

A new Harvard analysis details the administration’s case, which would limit the EPA’s ability to strengthen regulations when it determines hazardous air pollutants are more dangerous than previously thought.