Ethylene Oxide (ETO)




Common Name:


Chemical Name:

1,2 epoxy ethane

Chemical formula:

(CH2) 2 O

Physical Properties

Liquid below 10.76oC and 760 mm of Hg, lighter than water; but                               colorless gas at 25°C


Mustard-like, pungent (hard to detect at low concentration)

Boiling Point :

10.7 °C


Freezing Point :

-111.3 °C

Molecular Weight:



Specific gravity:

i) At gaseous stage :


ii) At liquid stage :

0.887 at 7°C

Vapour density at 20 oC:     1.52 gm/ml


Flammability           :

3 to 80% by volume                                       (highly inflammable)

Solubility in water:

Solubility in Water:     Infinite at 0°C

Chemical Properties

Highly reactive and inflammable; relatively non-corrosive.

Relation between weight and volume of Liquid:

Weight Volume

1 lb.  =

511.4 ml (7°C)

1 Kg. =

1127.35 ml

0.887 Kg.=

1 litre
Relation between dosages and concentration of Gas in air





1 gm/m3



16 gm/m3 or

1 lb/1000 cft.



Vapour Pressure at 20 0 C:    

1095 mm Hg

Mode of Action:


Threshold Limit value (TLV):

5 ppm

Effects on different commodities

Effect on Material:

Metals: Relatively non-corrosive.

4. Effect on Plants:

Germination of seed: Some seeds are tolerant like aster, damelion, Lucerne, mung bean, onion, pea, radish, spinach, sudan grass. Some are non-tolerant like seeds of barley, oats, wheat, corn, maize, beans, carnation, and nasturtium.

Phytotoxicity: Highly toxic to Growing plants; dormant plants, fresh fruits & vegetables.

Food articles: Reactive with Vitamin ‘B’; destroys amino acids, histidine, methionine and lysine.


Chemical residues in commodities treated with ETO may occur as follows: unchanged ETO, which may persist for some time after the treatment; compounds of low molecular weight, such as ethylene chlorohydrin, ethylene bromohydrin and ethylene glycol, produced by interaction of LTO with inorganic constituents of the commodity; alkylated and hyrdroxyethylated derivatives of food constituents such as sugars, amino acids, vitamins and proteins.

Method of Evolution as a fumigant

As it is highly inflammable gas, it is always used as a mixture with carbon dioxide at 1:9 ration ( ETO : CO2). The gas is discharged by natural pressure from gas cylinder.


Human beings: Poisonous by inhalation. Lethal dose: 50000 ppm


Unless special precautions are taken, there is danger of fire or explosion when ETO is being used. An explosion of the 1 : 9 mixture (ETO : CO2) may be caused by a static spark generated while the gas mixture is passing through a metal tube on its way from the cylinder to the chamber. Therefore, precautions must be taken against the building up of static electricity, by earthing all equipment.

Safety Measure:

Use a standard organic vapour canister. Carbon dioxide at high concentration may cause giddiness and suffocation. A Self contained Breathing Apparatus (SCBA) should be used in the fumigation space

Poison symptoms:

The liquid vaporises rapidly and can produce severe eye and skin burns. Ethylene oxide may cause delayed skin burns even if only dilute solutions remain on the skin. Short term exposures to ETO vapours can result in difficulty in breathing, coughing, lung irritation, dizziness, nausea, vomiting, unconsciousness, and even death. Longer exposure to high concentrations may cause severe damage to lungs, nervous system, reproductive system and other organs.

First Aid:

Keep the patient in warm place but not hot and in fresh air. Give warm water if nausea or vomiting occurs due to mild exposure. Physician should be consulted immediately.

Usage as Fumigant

Its use is limited as it is less toxic than other fumigants against insect pests. However, its microbial action can be used to eliminate fungal and bacterial pathogens to certain extent.