What Is Ethylene Oxide Used For in Food and Why Is It Regulated?

December 12, 2025 •

5 min read

While banned in the European Union and other regions, ethylene oxide is historically and, in some countries, currently used as a fumigant and sterilizing agent for certain food products like spices and herbs. Concerns over its carcinogenic and mutagenic properties have led to widespread recalls and stricter regulations, raising the question of what is ethylene oxide used for in food and whether it is safe.

Quick Summary

Ethylene oxide is used as a sterilant to control microbial contamination in dried foods such as spices and nuts. Due to its classification as a human carcinogen, many regions have banned or severely restricted its use, leading to global food recalls and shifts toward safer alternatives.

Key Points

Sterilization Use: Ethylene oxide is used as a fumigant for low-moisture foods like spices, herbs, and nuts to kill bacteria and pests.
Carcinogenic Risk: It is classified as a human carcinogen and mutagen, leading to significant health concerns from long-term exposure.
Regulatory Bans: Many countries, including all of the European Union, have banned its use in food production, mandating product recalls for any contamination above trace levels.
Contrasting Policies: Other regions, like the U.S. and Canada, permit controlled use on certain products with specified maximum residue limits.
Toxic By-products: The chemical can form toxic residues like 2-chloroethanol, which poses its own health risks.
Alternative Solutions: Safer alternatives to ethylene oxide include food irradiation and steam sterilization, which are becoming more widely adopted.
Supply Chain Challenges: The disparity in global regulations complicates international trade, increasing the risk of contaminated products entering markets where the chemical is banned.

Historical Use and Function of Ethylene Oxide in Food

Ethylene oxide (EtO) is a colorless, flammable gas that acts as a potent antimicrobial and sterilizing agent. In the food industry, its primary function has been as a fumigant for low-moisture foods, effectively killing bacteria, viruses, fungi, and insect pests that can contaminate products during storage and transportation. The gas's high reactivity allows it to penetrate packaging and destroy microorganisms by damaging their DNA.

Historically, products such as dried herbs, spices, nuts (like walnuts), and sesame seeds were treated with ethylene oxide to prevent the growth of pathogens like Salmonella and E. coli. This process was considered a reliable method for ensuring food safety, particularly for products that are not cooked before consumption or are added to other foods during manufacturing. The treatment was also prized for its ability to extend the shelf life of products by inhibiting spoilage and microbial degradation.

The Rise of Concern and Regulatory Action

Despite its effectiveness, evidence linking ethylene oxide to serious health risks began to mount. Research classified EtO as a mutagen and a human carcinogen, meaning it can cause genetic mutations and cancer. Long-term exposure, even at low levels, was associated with an increased risk of specific cancers, including leukemia and breast cancer. Furthermore, EtO can convert into a toxic by-product, 2-chloroethanol (2-CE), which also has potential health risks.

These safety concerns prompted food safety authorities worldwide to re-evaluate the use of EtO in food. This has resulted in a patchwork of regulations across the globe, with some regions imposing outright bans while others permit its use under strict maximum residue limits (MRLs). The contrasting regulatory approaches have created complications in international food trade, leading to numerous food recalls and increased scrutiny of supply chains.

Global Regulation of Ethylene Oxide in Food

Regulations in the European Union

The European Union has taken one of the strictest stances on ethylene oxide. The use of EtO as a pesticide and sterilant for food has been banned in the EU since at least 2011. In 2022, after a series of food safety incidents involving contaminated food additives like locust bean gum and guar gum, the EU further tightened regulations by setting a maximum residue level (MRL) for ethylene oxide and its metabolite 2-chloroethanol at the lowest level of quantification (0.1 mg/kg) for all food additives. This effectively makes any detectable amount of contamination above this limit grounds for mandatory recall and withdrawal from the market.

Regulations in the United States and Canada

In contrast to the EU, the United States and Canada permit the use of ethylene oxide for sterilizing certain food products, including spices, dried herbs, dried vegetables, and some nuts, but with specific MRLs in place. The U.S. Environmental Protection Agency (EPA) has long acknowledged the use of EtO for these purposes. However, the EPA also recognizes EtO as a human carcinogen (primarily via inhalation) and has called for a phased cancellation of some uses where alternatives exist.

Regulations in Other Regions

Regulations vary significantly elsewhere: Australia and New Zealand banned the use of EtO on food products sold domestically in 2003. China and Taiwan have a complete ban on its use in food. These differences mean that a product that is legal and compliant in one country might be considered unsafe and illegal in another, highlighting the complexity of modern food supply chains.

Alternatives to Ethylene Oxide for Food Treatment

Because of the growing health concerns and tightening regulations, the food industry has sought safer and more sustainable alternatives to ethylene oxide for food sterilization. The three most common alternatives are:

Irradiation: This process uses ionizing radiation to kill microorganisms and insects without raising the product's temperature significantly. It is highly effective but faces consumer perception issues regarding radiation exposure.
Steam Sterilization: This involves using superheated steam under pressure to kill pathogens. It is a natural process but can impact the flavor, color, and texture of delicate spices and herbs.
Other Gas Treatments: Some regions are exploring alternative gas treatments like ozone, but these methods require validation for effectiveness and safety on a product-by-product basis.

A Comparison of Food Treatment Methods


Feature	Ethylene Oxide Fumigation	Food Irradiation	Steam Sterilization
Efficacy	Highly effective against a broad spectrum of pathogens and pests.	Highly effective, especially for microbial and insect control.	Effective for most pathogens, but can be less so for heat-resistant bacteria.
Mechanism	Damages DNA of microorganisms via alkylation.	Damages DNA using ionizing radiation.	Kills microorganisms using heat and moisture.
Food Quality Impact	Generally low impact on product appearance and organoleptic properties.	Can cause slight changes to texture, flavor, or nutritional value depending on the product and dose.	Higher risk of altering flavor, color, and texture, particularly with sensitive products.
Health Concerns	Carcinogenic and mutagenic; creates toxic by-products (2-CE).	Generally considered safe by health authorities; public perception is a key issue.	Considered a safe, non-chemical treatment method.
Regulatory Status	Heavily restricted or banned in many countries (EU, Aus/NZ), permitted under MRLs in others (US, Canada).	Widely accepted and regulated in many countries, though specific food categories may be restricted.	Widely accepted and used globally as a natural sterilization method.
Cost	Relatively low cost due to established infrastructure and effectiveness.	Requires significant capital investment in specialized equipment.	Cost-effective and widely available technology.

Conclusion

While ethylene oxide has been historically valued for its efficacy in controlling microbial contamination and pests in low-moisture foods, its classification as a human carcinogen has fundamentally changed its status in the food industry. The stark differences in global regulation reflect the ongoing debate and risk assessment surrounding its use, with regions like the European Union implementing stringent bans and recall mandates. As regulatory oversight increases and health consciousness among consumers grows, the industry's shift toward safer alternatives like irradiation and steam sterilization will likely accelerate. Consumers and manufacturers must remain aware of the potential for ethylene oxide contamination, even in products where its use is prohibited, due to complexities in global supply chains. The drive for safer and more transparent food processing practices is paramount in ensuring the long-term health and trust of consumers. For more detailed information on regulations, visit the U.S. Environmental Protection Agency's website on hazardous air pollutants.

Frequently Asked Questions

Ethylene oxide is classified as a human carcinogen and mutagen by several health authorities, including the EPA. This means that long-term exposure, even at low levels, can increase the risk of certain cancers, such as leukemia and breast cancer. It also produces a toxic metabolite called 2-chloroethanol.

Many regions have banned or strictly restricted the use of ethylene oxide in food. Most notably, the entire European Union has prohibited its use, and Australia and New Zealand have had a domestic ban in place since 2003. China and Taiwan also prohibit its use.

Yes, in the United States, ethylene oxide is still used for sterilizing certain foods like spices, dried herbs, and nuts, with specific maximum residue limits established by the EPA. The use is primarily aimed at controlling microbial contamination like Salmonella.

Foods that are typically treated with ethylene oxide are low-moisture products that are difficult to sterilize by other means. This includes dried herbs, spices, dried vegetables, sesame seeds, and walnuts.

2-chloroethanol (2-CE) is a toxic by-product of ethylene oxide treatment. It is formed when ethylene oxide reacts with chloride in the treated food. Due to its potential toxicity, some authorities assess its health risk to be similar to that of ethylene oxide, leading to its inclusion in residue limits.

In regions with strict bans, such as the EU, any food found to have ethylene oxide residues above the low limit of quantification must be withdrawn from the market and recalled from consumers. This applies to both raw materials and finished products.

Common and safer alternatives include food irradiation, which uses radiation to kill pathogens, and steam sterilization, which uses high-temperature steam. Both methods effectively reduce microbial load but may have different effects on food quality compared to chemical treatment.