Trevi installation for ethylene oxide waste gas treatment

Cost-effective EtO abatement for U.S. commercial sterilisers

Trevi designs, builds and maintains ethylene oxide (EtO) abatement systems for sterilization facilities and chemical plants.

Over the last 30 years, Trevi has delivered more than 110 installations worldwide.

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Combined treatment line: three wet scrubbers and a Biofilter (BEtO) with one stack

Essential for healthcare, strictly regulated

Ethylene oxide sterilizes about half of all medical devices in the United States every year. EPA also identifies EtO as a cancer-causing chemical. That is why U.S. rules on EtO emissions and worker exposure have been tightened and revised several times since 2024.

  • ~50% of U.S. medical devices are sterilized with EtO
  • ~90 commercial sterilization facilities in the U.S.
  • 30 years of EtO abatement experience at Trevi

EPA rules for commercial sterilizers: where things stand

U.S. rules for ethylene oxide (EtO) emissions from commercial sterilization facilities have changed several times since 2024.

01

March 2024 - Final rule

EPA finalized amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for EtO commercial sterilization, published on April 5, 2024. EPA projected that the rule would reduce EtO emissions from nearly 90 commercial sterilization facilities by about 90%. For facilities using at least 10 tons of EtO per year, the rule requires 99.6% control for existing aeration room vents and 99.9% for new ones.
02

March 2025 - Reconsideration

EPA announced that it would reconsider the 2024 rule.
03

July 2025 - Presidential exemption

Proclamation 10959 of July 17, 2025 extended the compliance deadlines by two years for the facilities listed in its annex.
04

March 2026 - Proposed amendments

EPA proposed to rescind the risk-based standards of the 2024 rule, to set the standard for new aeration room vents at 99.6%, to let all facilities choose between parametric monitoring and continuous emission monitoring, and to rescind the nationwide permanent total enclosure requirement. The comment period closed on May 1, 2026.
05

What comes next?

Your requirements depend on your EtO use, your permit and the outcome of the reconsideration.

Worker exposure: the FIFRA Interim Decision

On January 14, 2025, EPA released an Interim Decision for ethylene oxide under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). For commercial sterilizers, it lowers worker exposure limits in steps and adds workplace measures.

Required measures

  • Respirators for high-exposure tasks, such as connecting and disconnecting EtO containers
  • Continuous monitoring of EtO concentrations, including at on-site storage
  • Separate HVAC systems for areas that use EtO and areas that do not
Period Worker exposure limit (8-hour TWA)
Until end of 2027 1.0 ppm
By 2028 0.5 ppm
By 2030 0.25 ppm
By 2035 0.1 ppm

Four technologies for every EtO stream

Smart Wet Scrubber (SwEtO) for ethylene oxide abatement

Smart Wet Scrubber - SwEtO
Acid Wet Scrubber (AcEtO) for ethylene oxide abatement

Acid Wet Scrubber - AcEtO
Aerial view of the Biofilter (BEtO) for ethylene oxide abatement at a sterilisation site in Thailand

Biofilter - bEtO
Dry Scrubber (DEtO) with solid sorbent for low EtO concentrations

Dry Scrubber - dEtO

Speak to an EtO expert

Tell us about your EtO challenge, and we’ll help you find the right solution.

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