Ethylene oxide is classified as a flammable gas and a known human carcinogen. US imports must comply with DOT Pipeline and Hazardous Materials Safety Administration (PHMSA) packaging and labeling requirements, and facilities storing it above threshold quantities are subject to EPA Risk Management Program (RMP) rules. Importers should also verify TSCA compliance before entry.

Ethylene oxide is classified under a single chemical identity regardless of end use, but its intended application — industrial feedstock versus medical/food sterilant — can trigger different regulatory reviews. Sterilant-grade EO used on food contact surfaces or medical devices may require additional FDA or EPA registration, separate from the customs entry process.