Ethylene Oxide (EtO), or the EtO gas, is the backbone for sterilising medical devices and chemical building blocks for everyday products like plastics, textile, detergents, adhesives and antifreeze, it has a downside too. The gas possesses serious health risks. Prolonged ethylene oxide exposure health effects include many physical, acute and chronic risks such as cancers, including lymphoma, leukemia, and breast cancer. Health risks also include other health problems like cognitive impairment, reproductive harm and neurological issues.
Although the EtO sterilization gas safety regulations mandate a lengthy aeration phase (often 8-12 hours), which allows the toxic gas to dissipate from items it has been exposed to, the workers in the facilities where EtO is being used, and communities living nearby, remain at risk. Regulatory bodies set worker safety ethylene oxide exposure limits to ensure worker’s safety. The Environmental Protection Agency (EPA) strictly regulates EtO level exposure, and recently, EPA has proposed amendments to the Biden-era 2024 National Emissions Standards for Hazardous Air Pollutants (NESHAP) for Ethylene Oxide (EtO) Commercial Sterilization Facilities to ensure consistency with the law and gold standard science to ensure worker safety. Many regulatory bodies like OSHA, NIOSH and ACGIH also decide the limit value, permissible exposure limit and recommended exposure limits.
The question arises, why are environmentalists and scientists concerned about the EtO levels in the air? What impacts does this gas cause on air quality and workers’ safety? Let’s understand the EtO gas in detail.
What Is EtO Gas?
Ethylene oxide (EtO) is a versatile but hazardous industrial gas with the chemical formula C₂H₄O, characterised by a highly strained three-membered epoxide ring that makes it exceptionally reactive toward water, DNA, and proteins. Physically, it is a colourless gas at room temperature with a faintly sweet, ether-like odour, a boiling point of just 10.7 °C (51.3 °F), and a density slightly greater than air, causing it to accumulate near the floor. It is highly flammable, with a lower explosive limit of 2.6% by volume in air, and it dissolves readily in water and organic solvents. These chemical and physical properties, low-temperature reactivity, deep penetrability, and explosivity underpin both its value as a sterilising agent and the stringent safety standards governing its use.
Uses Of EtO Gas:
The primary uses of ethylene oxide (EtO) gas:
Sterilisation of Medical Equipment:
Sterilisation of medical equipment is the most critical use. EtO sterilises heat- and moisture-sensitive devices such as surgical kits, catheters, pacemakers, ventilators, and plastic gowns. This is the most potent medical equipment sterilisation technique, but it brings medical device sterilisation emission risks for workers and communities.
Chemical Intermediate – The Raw Material for Producing Ethylene Glycol:
EtO is used to make:
- Antifreeze and coolants
- Polyester fibres (for clothing and bottles)
- Polyethylene terephthalate (PET) resins
Industrial Solvent:
EtO is used in the production of solvents like ethylene glycol ethers for paints, coatings, and cleaning agents.
Fumigant for Spices and Herbs:
Used to control microbial contamination in dried spices, herbs, and certain food products (though use is being phased out or restricted in many regions).
Production of Surfactants:
EtO is used to manufacture ethoxylates, which are key ingredients in detergents, soaps, and personal care products.
Pharmaceutical Manufacturing:
EtO is used as a chemical building block for certain drugs and pharmaceutical intermediates.
Cosmetics and Personal Care:
Ethylene oxide derivatives (e.g., polysorbates, laureths) serve as emulsifiers and thickeners in lotions, creams, and shampoos.
Despite its diversified uses, EtO is a hazardous gas with significant impacts on the air quality and worker safety.
Impacts Of EtO On Air Quality:
As a hazardous air pollutant, EtO emissions degrade air quality primarily by significantly increasing cancer risk in nearby communities, a threat made worse because it persists in the air for months and can travel far from its source. For these reasons, ethylene oxide air quality monitoring is difficult with standard methods. Facilities must look for solutions to improve the indoor air quality and install ethylene oxide air quality monitoring devices to mitigate the arising risks timely and efficiently.
Euromate Pure Air provides comprehensive solutions to purify toxic gases like EtO from the workplace environment. We provide effective solutions for EtO monitoring and achieving desired levels for worker safety ethylene oxide exposure limits.
Carcinogenic Hazard:
Ethylene oxide exposure health effects include cancer as one of the most dangerous effects. EtO is classified by the EPA as a known human carcinogen. Long-term inhalation of EtO is linked to cancers such as breast cancer, leukemia, and non-Hodgkin lymphoma. The EPA’s lifetime cancer risk benchmark for air pollutants is 1 in 1 million, but studies have found ambient levels of EtO in some regions a thousand times higher than levels considered safe for long-term exposure.
Atmospheric Persistence:
Ethylene oxide air quality monitoring discloses that EtO is a stable compound that can persist in the atmosphere for 70 to 150 days (half-life). In that time, it can travel long distances from its source before breaking down, impacting a much wider area.
Difficult Monitoring:
Standard air sampling methods struggle to capture EtO accurately because it is highly volatile, often making it hard to detect and measure in ambient air without specialized equipment. This has historically led to underestimations of its presence and risk.
Environmental Injustice:
EtO’s impact on air quality is not evenly distributed; facilities emitting the gas are disproportionately located in or near low-income communities and communities of color, making it a significant environmental justice concern.
Impacts of EtO on Workers’ Safety:
From immediate physical dangers to life-threatening chronic illnesses, EtO exposure presents severe hazards to worker safety. Therefore, regulatory bodies instill strict laws for worker safety ethylene oxide exposure limits.
Physical Hazards
Beyond the toxic impacts of EtO on workers’ health, it also possesses a fire and explosion risk. EtO is an extremely flammable gas that can form explosive mixtures with air. Explosions in industrial EtO facilities have been reported to cause workers’ injuries and deaths.
Immediate Health Impacts
Short-term or acute exposure to high levels of EtO can result in irritation to the eyes, skin, nose and throat. It can also cause immediate harm just as respiratory irritation and lung injury. The liquid form can cause severe skin irritation, blistering and even frostbite due to rapid evaporation.
Acute exposure can also cause systemic symptoms like headaches, vomiting, nausea, diarrhea, shortness of breath, dizziness, coughing and fatigue. Severe systemic symptoms can also cause cyanosis. Acute high-level exposure can lead to convulsions and delayed peripheral neuropathy.
Long-Term Health Risks
Long-term, repeated exposure to EtO, even at lower levels, is associated with severe chronic diseases. One of the main health risks is cancer, as EtO is a known human carcinogen. A quantitative assessment estimated significant cancer deaths among exposed workers. Secondly, chronic EtO exposure has been linked with neurological effects such as numbness, memory loss and general neurotoxicity. It can also affect the liver and kidneys.
Lastly, EtO exposure is linked to reproductive effects such as spontaneous abortion, lower sperm counts and testicular degeneration. As EtO is a mutagen, it causes damage to genetic material, potentially leading to heritable mutations.
Air quality measurement and management and limiting exposure to toxic EtO gas is mandatory to protect the workers. Euromate Pure Air is an air purification tech company with products aimed at reducing toxic gases, pollutants, odour and airborne viruses from the environment. Check out our product range here. It is also recommended to provide Personal Protective Equipment (PPE), chemical-resistant gloves and clothing and adequate training on proper emergency procedures and dangers of EtO. EtO using facilities must include effective controls using local exhaust ventilation, separate HVAC systems and continuous area monitoring to manage EtO levels regularly and handling accidental releases.
