Sunday, June 22, is a Code Orange Air Quality Action Day for Ozone in Delaware
¡Domingo 22 de Junio es un Día de Acción por la Calidad del Aire de Código Naranja para el Ozono en Delaware!
Dimanch 22 Jen an se yon Jounen Aksyon Kòd Oranj pou Kalite Lè a pou Ozòn nan Delaware! More Info

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Ethylene Oxide



DNREC understands that Delaware residents have concerns and questions about ethylene oxide (often abbreviated as EtO). This page provides information on what EtO is and its impacts to human health. This page also provides links to federal and other state resources that provide more in-depth information on EtO.

A view across the Delaware river from under a tree.

What is Ethylene Oxide?

Ethylene oxide (EtO) is a colorless gas with a faintly sweet odor. It is a volatile organic compound (VOC) and hazardous air pollutant (HAP).

EtO is used in the production of consumer products and to sterilize materials that can’t be sterilized by steam.

What We Know About Ethylene Oxide

In recent years, the U.S. Environmental Protection Agency (EPA) determined that EtO poses a greater risk to human health than previously believed, particularly regarding its cancer risk association. The EPA’s risk assessment for EtO was revised in 2016.

The risk to public health stems from emissions of EtO from facilities that use it as part of their operation.

How is Ethylene Oxide Used in Delaware?

There is one permitted facility in Delaware that produces, uses and emits EtO — Croda Inc.’s Atlas Point facility, located at 315 Cherry Lane, in New Castle.

Croda produces EtO and uses EtO to make ingredients for consumer products.

What is DNREC Doing to Address Ethylene Oxide?

The DNREC Division of Air Quality reviews emission data and permits for EtO in Delaware.

Since 2016, DNREC has worked extensively with Croda to reduce their EtO emissions by almost 90% through permitting and enforcement.

DNREC continues to prioritize emission reductions as the best way to reduce health risks associated with EtO.

What is Being Done Nationally to Control Ethylene Oxide?

The best way to reduce risks associated with EtO is to reduce emissions of EtO.

In recent years, the EPA has required large (major) sources of hazardous air pollutants to implement stricter control measures to reduce EtO emissions.

At the end of 2024, the EPA proposed requiring smaller (area) sources which emit EtO to implement the same control measures as large sources.

Although Croda Inc.’s Atlas Point facility is a major source for some pollutants in Delaware, it is not a major source of hazardous air pollutants. Therefore, it was not subject to the first rule.

If the new EPA proposal is finalized, Croda Inc. would be subject to the Chemical Manufacturing Area Sources (CMAS) National Emission Standards for Hazardous Air Pollutants (NESHAP) rule.

Where Can I Get Information About Risk Where I Live?

The EPA uses emission inventory data to model and predict risk at the census block level across the country.

EPA’s AirToxScreen is a mapping and screening tool which provides communities with information about health risks from hazardous air pollutants, which are also called air toxics.

EPA updates the AirToxScreen modeling regularly. The most recent national update included emission inventory data from 2020.

It is important to note that EPA has also modeled 2021 data for the census blocks around Croda. This modeling showed that due to decreased emissions in 2021, the risk decreased to below EPA’s actionable level.

How Can I Get More Information?

You can contact the DNREC Division of Air Quality by calling 302-739-9402 or emailing DAQpermittinginfo@delaware.gov. To find more information about EtO, please visit the links provided below.

Related Links and Information

Ethylene Oxide

Hazardous Air Pollutants: Ethylene Oxide (EPA)

Frequent Questions: Health Information About Ethylene Oxide (EPA)

Risk Reports for Ethylene Oxide (EPA)

Interstate Technology & Regulatory Council (ITRC), Ethylene Oxide Emissions Guidance

Croda Inc.

Atlas Point: Our local Delaware community (Croda)

The Croda Atlas Point Plant (DNREC)

Public Health Information

Delaware Cancer Statistics (DHSS)

Delaware Public Health Route 9 Report (DPH)

Proposed EPA Action

Proposed rule from EPA to reduce ethylene oxide emissions

Factsheet for proposed EPA rule

2022 DNREC, DHSS and EPA Meeting

Virtual Informational Meeting (April 13, 2022)

Meeting Presentation

Report from Division of Public Health

Meeting Recording

Meeting Follow-up Questions and Answers

Original DNREC EtO Page

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