Ethylene Oxide (EtO)
Gas Sterilization

Ethylene Oxide is a sterilant chemical often used in healthcare sterile processing and medical device manufacture. Ethylene Oxide is flammable, toxic, and a known carcinogen. Know the facts for process management and safety.

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Chemical Overview

Applications For Use

Dangers of Hydrogen Peroxide

Regulations & Standards

Safety Practices

Ethylene Oxide Monitor

Monitoring Your Environment

Get To Know Ethylene Oxide

Ethylene Oxide (EtO or EO) is produced in large volumes colorless and odorless, as well as, flammable and explosive.  It is a highly toxic, penetrating gas and is most often used as an intermediate in the production of other chemical gases and as a sterilizing gas for medical devices and instruments.  EtO is also used as an in the production of other chemicals, the most recognizable one being ethylene glycol.  Unfortunately, Ethylene Oxide possesses multiple physical and health hazards that call for special attention. Monitoring the breathing environment near Ethylene Oxide gas sterilization equipment is important because this is an area that calls for special attention when it comes to Ethylene Oxide (EtO).  Every environment that is using Ethylene Oxide, should pair their work environment with a ChemDAQ Air Monitor, to make sure workers are safe. 

Microbial Activity: Ethylene oxide has been shown to be effective as a sterilant against all forms of microorganisms, including bacterial spores and protozoal cysts. EtO is a direct alkylating agent that does not require metabolic activation, and its microbiologic inactivation properties are the result of alkylation cellular aconstituents of organisms, such as nucleic acid and functional proteins, including enzymes, which leads to consequent denaturation.

Keep your employees safe by monitoring ethylene oxide.

Applications for Ethylene Oxide (EtO) Gas Sterilization:

  • Medical device manufacturing
  • Low temperature steriliztion process for medical instruments
  • Low temperature sterilization process for medical packs

What are the dangers of Ethylene Oxide Gas Sterilization?

The dangers of Ethylene Oxide, and the need to monitor ETO gas vapor, are well established.  One of the biggest dangers of Ethylene Oxide gas is that EtO is a known human carcinogen and overexposure to EtO can pose many negative health effects.  It presents significant challenges to those who work with Ethylene Oxide sterilization processes in hospital and commercial applications.  No worker should not know how much Ethylene Oxide they're breathing in, especially because it is a known human carcinogen. Workers are also at risk while Ethylene Oxide off-gassing, and without monitoring the off-gassing in the air, your employees are at risk.

Ethylene Oxide is difficult to monitor due to cross-interference from common chemicals, such as, alcohol and carbon monoxide vapors.  This often leads to inaccurate readings and false alarms.

Patented Chemical Filter Provides ETO Sensor Specificity

ChemDAQ incorporates a unique and patented filter in all of it's Ethylene Oxide sensors, providing true and accurate readings of Ethylene Oxide vapor exposure.

  • Eye irritation  : eye damage after prolonged exposure

  • Nose and throat irritation

  • Skin irritation dermatitis

  • Respiratory distress

  • Known human carcinogen

  • Affects both the female and male reproductive systems

  • Birth defects

  • Increased risk of miscarriage

Regulations/ Guidelines for Ethylene Oxide

Exposure limits and guidelines when using ethylene oxide have been set by a number of national agencies including the following:

OSHA: Occupational and Safety Health Administration
OSHA Permissible Exposure Limit (PEL) :  1.0 ppm (8 Hr TWA)
    -Duties: Employers have a duty to provide a safe work environment     and employees have a duty to work safely.
    -Hazard Communication Regulation, suppliers (labels, safety data     sheets), Employers (facilities, work practices, training and personal     protective equipment) to enable the safe use of the chemicals

NIOSH: National Institute of Occupational Safety and Health
NIOSH Immediately Dangerous to Life and Health (IDLH) :  800 ppm

JC: Joint Commission
Joint Commission Standard EC.02.02.01

ACGIH : American Conference of Government Industrial Hygienist
ACGIH Threshold Limit Values TLV
:  1.0 ppm  (8 Hr TWA)
OSHA Hazard Communications 29 CFR 1910.1200

: Association for the Advancement of Medical Instrument
AAMI ST:41:1999 and ST:58:2013

: United Kingdom Health & Safety Executive
UK HSE Long-Term
: 5 ppm  

1 ppm (8 Hr TWA)

Monitoring EtO

It is highly recommended to use a combination of continuous fixed area monitoring and portable area monitoring to find danger zones throughout any facility that uses Ethylene Oxide.

Continuous fixed area monitoring is recommended in the following areas:

  • Near concentrated EtO sterilizers, storage areas, dilution lines, and pump stations

  • Any area where employees have experienced symptoms or known risks are present for exposure

Portable monitoring is recommended as checks needed on Ethylene Oxide throughout the day.

Important to note: Ethylene Oxide sterilizers can leak, so you may experience different levels per day. The same goes for sprayers that put off different levels of sanatation per day. Make sure to incorporate vapor monitoring into you QC and safety program. Monitoring will be used to access real-time exposure to hydrogen peroxide sterilization on a daily basis. Facilities can use these monitors to improve work practices, optimize engineering controls and/or add PPE as needed to ensure the safe use of Ethylene Oxide.

Handling EtO

At a minimum, chemical-resistant gloves (Neoprene) and splash-proof eye protection should be worn.

Adding a face shield is appropriate if working with larger quantities.

Concentrated Ethylene Oxide should only be handled in well-ventilated areas.

Prolonged exposure, or exposure above OELs may require the use of a suitable respirator. If a respirator is used, it should be full face to protect eyes.

Storage In Healthcare

Since use cartridges, no more than one day supply and < 12 cartridges near Ethylene Oxide sterilizer. Cartridges should be stored in approved flammable cabinet that must be actively vented and monitored to prevent a build up of EtO gas.

EtO use often requires permitting, dedicated ventilation, emissions control and special training. Consult appropriate regulations and standards for guidance.

EtO    Spill Control

Since EtO is a gas under normal conditions, any spills or leaks will rapidly vaporize and will be removed by ventilation. EtO should only be used in well ventialted areas, typically 10 air exchanges per hour (see local regulations). In the event of a leak, it is important to take measure to prevent worker exposure. Emissions regulations may also apply.

    Monitoring solutions for Ethylene Oxide.

    ChemDAQ’s Ethylene Oxide gas sterilization monitor provides real-time readings of vapor levels in the air for safety assurance.  Make sure to use our resources below to make sure every employee is safe while working around Ethylene Oxide.