[11] It is so flammable and extremely explosive that it is used as a main component of thermobaric weapons;[12][13] therefore, it is commonly handled and shipped as a refrigerated liquid to control its hazardous nature.

[citation needed] The epoxy cycle of ethylene oxide is an almost regular triangle with bond angles of about 60° and a significant angular strain corresponding to the energy of 105 kJ/mol.

[35] The carboxylate ion acts as nucleophile in the reaction: Ethylene oxide reacts with ammonia forming a mixture of mono-, di-, and tri- ethanolamines.

One method is the cationic cyclopolymerization of ethylene oxide, limiting the size of the formed cycle:[43] To suppress the formation of other linear polymers the reaction is carried out in a highly dilute solution.

[52] At the first stage, the catalyst (MXm) is initiated by alkyl-or acylhalogen or by compounds with active hydrogen atoms, usually water, alcohol, or glycol: The resulting active complex reacts with ethylene oxide via the SN2 mechanism: The chain breaks as Anionic polymerization of ethylene oxide is assisted by bases, such as alkoxides, hydroxides, carbonates, or other compounds of alkali or alkaline earth metals.

They result in a gas mixture containing acetaldehyde, ethane, ethyl, methane, hydrogen, carbon dioxide, ketene, and formaldehyde.

[53] High-temperature pyrolysis (830–1,200 K (557–927 °C; 1,034–1,700 °F)) at elevated pressure in an inert atmosphere leads to a more complex composition of the gas mixture, which also contains acetylene and propane.

The chlorohydrin process was unattractive for several reasons, including low efficiency and loss of valuable chlorine into calcium chloride.

[70] Older factories typically use air for oxidation whereas newer plants and processes, such as METEOR and Japan Catalytic, favor oxygen.

[74] The catalyst for the reaction is metallic silver deposited on various matrixes, including pumice, silica gel, various silicates and aluminosilicates, alumina, and silicon carbide, and activated by certain additives (antimony, bismuth, barium peroxide, etc.).

Elevated pressure of 1–3 MPa (150–440 psi) increases the productivity of the catalyst and facilitates absorption of ethylene oxide from the reacting gases.

Also, a small proportion of the gas leaving the ethylene oxide scrubber (0.1–0.2%) is removed continuously (combusted) to prevent the buildup of inert compounds (N2, Ar, and C2H6), which are introduced as impurities with the reactants.

[91] Shell OMEGA technology (Only Mono-Ethylene Glycol Advantage) is a two-step synthesis of ethylene carbonate using a phosphonium halide as a catalyst.

[citation needed] The major industrial esters of mono-, di-, and triethylene glycols are methyl, ethyl, and normal butyl ethers, as well as their acetates and phthalates.

The synthesis involves reaction of the appropriate alcohol with ethylene oxide:[93] The reaction of monoesters with an acid or its anhydride leads to the formation of the esters: In the industry, ethanolamines (mono-, di-, and triethanolamines) are produced by reacting ammonia and ethylene oxide in anhydrous medium at a temperature of 40–70 °C (100–160 °F) and pressure of 1.5–3.5 MPa (220–510 psi) MPa:[94] All three ethanolamines are produced in the process, while ammonia and part of methylamine are recycled.

Hydroxyalkylamines are produced in a similar process: Monosubstituted products are formed by reacting a large excess of amine with ethylene oxide in presence of water and at a temperature below 100 °C (212 °F).

[95][96] Industrial production of ethoxylates is realized by a direct reaction of higher alcohols, acids, or amines with ethylene oxide in the presence of an alkaline catalyst at a temperature of 120–180 °C (250–360 °F).

In the United States, the operation of EtO sterilization is overseen by the EPA through the National Emissions Standards for Hazardous Air Pollutants (NESHAP).

[80] An inexpensive test for ethylene oxide exploits its precipitation of solid hydroxides of metals when it is passed through aqueous solutions of their salts: Similarly, ethylene oxide is detected by the bright pink color of the indicator when passing air through aqueous solutions of some salts of sodium or potassium (chlorides, iodides, thiosulfates, etc.)

[119][120] The accident launched substantial debris over a radius of about two and a half kilometers, one piece penetrating a distant home and killing an occupant.

[124][125] In September, alert was raised by Belgium by RASFF, but the product has also been sold in other EU single market countries such as France[126] and Ireland.

A 2003 study of 7,576 women exposed while at work in commercial sterilization facilities in the US suggests ethylene oxide is associated with breast cancer incidence.

"[133] An increased incidence of brain tumors and mononuclear cell leukemia was found in rats that had inhaled ethylene oxide at concentrations of 10, 33 or 100 mL/m3 (0.0100, 0.0329 or 0.0997 imp fl oz/cu ft) over a period of two years.

There is evidence from both human and animal studies that inhalation exposure to ethylene oxide can result in a wide range of carcinogenic effects.

[135] At concentrations in the air about 200 parts per million, ethylene oxide irritates mucous membranes of the nose and throat; higher contents cause damage to the trachea and bronchi, progressing into the partial collapse of the lungs.

Even then, the odor of ethylene oxide is sweet and aromatic and can easily be mistaken for the aroma of diethyl ether, a common laboratory solvent of very low toxicity.

In view of these insidious properties, continuous electrochemical monitoring is standard practice, and it is forbidden to use ethylene oxide to fumigate building interiors in the EU and some other jurisdictions.

Ethylene oxide easily penetrates through ordinary clothing and footwear, causing skin irritation and dermatitis with the formation of blisters, fever, and leukocytosis.

"[8] The United States EPA published an advance notice of proposed rulemaking (NPRM) in the 12 December 2019 Federal Register seeking to limit EtO emissions.

In 2024, U.S. probed claims that popular Indian curry brands MDH and Everest Spices carried ethylene oxide after Hong Kong and Singapore found the contamination in the products and took enforcement actions against them.