Ethylene Oxide EPA Facts

Ethylene oxide is a colorless and flammable gas with a faintly sweet odor, represented by the chemical formula C2H4O. It is an important industrial chemical used primarily in the production of various consumer goods and chemicals, such as antifreeze, detergents, and plastics. Ethylene oxide is valued for its ability to act as a versatile intermediate in the synthesis of diverse organic compounds. Despite its utility, the compound poses potential hazards due to its carcinogenic and mutagenic properties, necessitating careful handling and storage to ensure worker safety. Ethylene oxide has no residential applications and should not be found in a home. OSHA limits and regulations on ethylene oxide do not apply to residences or residential neighborhoods. EPA values should be used in residential situations such as homes and neighborhoods.

EPA Non-cancer Limit: 18 ppb

EPA Cancer Risk Limit: .0001 ppb (one in a million increased lifetime cancer risk over 70 years)

EPA Document:

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Atmospheric Concentrations: URBAN/SUBURBAN: Ethylene oxide was targeted but not detected at 25 sites throughout Minnesota tested over an 8 year span from 1991-1998. (

Ethylene oxide (CASRN 75-21-8) is a significant chemical compound with multifaceted applications in various industries. Its primary use lies as a crucial chemical intermediate in the production of ethylene glycol, which is widely employed in antifreeze, textiles, detergents, polyurethane foam, and other consumer products. Additionally, ethylene oxide finds utility as a sterilizing agent for medical equipment and as a fumigating agent for spices, ensuring the safety and preservation of various goods. Ethylene oxide can also be accidentally off-gassed and used in some illegal methamphetamine production methods including the P2P method.

Despite its industrial importance, ethylene oxide poses health hazards, and understanding its potential effects is crucial. Acute exposure to high levels of ethylene oxide in humans can result in adverse effects on the central nervous system, leading to symptoms like nausea, vomiting, and neurological disorders. Moreover, dermal or ocular contact with ethylene oxide solutions may cause irritation of the skin and eyes.

Chronic exposure to ethylene oxide in humans can lead to a range of health issues, including irritation of the eyes, skin, nose, throat, and respiratory passages. Long-term exposure may also lead to detrimental effects on the nervous system, such as headaches, nausea, memory loss, and numbness. Furthermore, there is some evidence linking ethylene oxide exposure to reproductive effects, with data indicating an increased rate of miscarriages in female workers exposed to the chemical.

Of particular concern is ethylene oxide’s association with cancer. Human occupational studies have shown elevated cases of lymphoid cancer and breast cancer in female workers exposed to the compound. In animal studies, ethylene oxide exposure through inhalation has been demonstrated to cause various types of cancer, including lymphoid cancer, brain tumors, lung tumors, tumors of connective tissue, uterus, and mammary gland.

As a result of these findings, the Environmental Protection Agency (EPA) has classified ethylene oxide as a known human carcinogen when inhaled. The World Health Organization (IARC) has classified ethylene oxide as a Class 1 Known Human Carcinogen. The EPA estimates the risk of developing cancer from continuous exposure to air containing ethylene oxide at different concentrations. For instance, if an individual were to breathe air with an average concentration of 2 × 10-4 µg/m3 (.0001 ppb) over their entire lifetime, the theoretical increased chance of developing cancer would be no more than one in a million. This is the widely used EPA/ATSDR limit for ethylene oxide.

Personal exposure to ethylene oxide can be assessed through various tests, such as determining the chemical’s concentration in blood or the amount exhaled from the lungs. Certain occupational groups, including workers in ethylene oxide manufacturing or processing plants, sterilization technicians, and those involved in fumigation, may be at a higher risk of exposure, and monitoring of their exposure levels is crucial.

Ethylene oxide plays a vital role in numerous industries, but its potential health hazards necessitate careful handling and regulation to protect both workers and the general population. Awareness of its effects on human health, particularly its carcinogenic properties, is essential in ensuring safety and implementing appropriate measures to mitigate risks associated with its use and handling.

Acute exposure to ethylene oxide refers to short-term contact with the chemical at high levels. When individuals encounter ethylene oxide in this manner, they may experience immediate effects such as nausea, vomiting, and neurological disturbances. Additionally, irritation of the eyes and mucous membranes can occur.

On the other hand, chronic exposure to ethylene oxide involves long-term and repeated contact with the chemical, typically at lower levels. Over time, this prolonged exposure can lead to persistent health issues, including irritation of the eyes, skin, nose, throat, and respiratory passages. Furthermore, chronic exposure may affect the nervous system, resulting in symptoms like headaches, nausea, memory loss, and numbness.

It’s important to recognize the distinction between acute and chronic exposure, as they can have varying impacts on health. While acute exposure may cause immediate discomfort and acute health effects, chronic exposure’s effects may manifest gradually, potentially leading to more long-lasting and serious health problems. Therefore, proper precautions and monitoring are essential to safeguard against potential risks associated with both types of exposure to ethylene oxide.

How to Measure Ethylene Oxide Down to EPA Limits

There are various analytical techniques utilized for quantifying ethylene oxide (C2H4O) at low levels in ambient air. Ethylene oxide, an essential chemical intermediate in industrial processes, poses potential health hazards at elevated concentrations. Hence, monitoring ethylene oxide at trace levels is crucial for regulatory compliance and public safety. The methods discussed herein include gas chromatography (GC), mass spectrometry (MS), photoionization detector (PID), Fourier transform infrared (FTIR) spectroscopy, cavity ring-down spectroscopy (CRDS), passive sampling devices, preconcentration techniques, real-time monitoring with Mid-Infrared (MIR) spectroscopy as the preferred method.

Ethylene oxide is an indispensable compound used in the production of consumer goods, textiles, detergents, and polyurethane foam. However, its presence at trace levels poses potential health risks, necessitating accurate monitoring at low concentrations.

Quantifying ethylene oxide at trace levels is essential for regulatory compliance and protecting public health and the environment. Each analytical technique discussed in this review offers specific advantages and limitations. Researchers must carefully consider the required sensitivity and context of their application to select the most suitable method. MIR spectroscopy stands out as a powerful tool for real-time monitoring, enabling quantification at unprecedented ppt levels, and contributing significantly to ensuring a safe and sustainable environment. Rigorous quality control and calibration remain pivotal for obtaining accurate and reliable results, instilling confidence in the collected data for safeguarding human health and environmental well-being.

Isomers Can Block the Easy Measurement of Ethylene Oxide Using GC-MS

Isomers of ethylene oxide can potentially interfere with its measurement using Gas Chromatography-Mass Spectrometry (GC-MS) due to their similar chemical structures. GC-MS is a powerful analytical technique that separates and identifies compounds based on their mass-to-charge ratios. However, if there are isomers of ethylene oxide present in the sample being analyzed, they may elute from the gas chromatograph at similar retention times as ethylene oxide, making it difficult to distinguish them based solely on their elution times.

Since the mass spectrometer identifies compounds based on their mass-to-charge ratios, isomers with similar molecular weights can also produce overlapping mass spectra, further complicating the identification process. This can lead to false positives or inaccurate quantification of ethylene oxide, especially in complex sample matrices where multiple isomers may be present.

To overcome potential isomeric interferences and enhance the accuracy of ethylene oxide measurements in Gas Chromatography-Mass Spectrometry (GC-MS), several strategies can be employed. One approach is the use of calibration standards and reference spectra to verify the presence of ethylene oxide and differentiate it from isomeric compounds based on their unique mass spectra.

In addition to traditional GC-MS, two advanced analytical techniques have shown promise in overcoming isomeric blocking: Cryo-cooled GC-MS and Mid-Infrared (MIR) laser technology. Cryo-cooled GC-MS involves cooling the chromatographic column to very low temperatures, which can increase separation between isomeric compounds and improve detection specificity.

MIR laser technology, on the other hand, utilizes infrared light absorption by molecular vibrations to quantify ethylene oxide at trace levels. This advanced technology provides high selectivity and sensitivity, enabling precise measurements even in the presence of interfering isomers. MIR laser technology has emerged as a preferred method for real-time monitoring of ethylene oxide, offering exceptional performance in detecting and quantifying the compound, while minimizing potential isomeric interferences.

By combining these strategies, researchers and analysts can achieve reliable and accurate ethylene oxide measurements, essential for various applications, including industrial safety, environmental monitoring, and medical research. Proper method selection, sample preparation, and chromatographic conditions are paramount to mitigating isomeric interferences and obtaining trustworthy ethylene oxide data for informed decision-making and comprehensive analysis.

MIR Laser Technology for Measuring Ethylene Oxide

Monitoring ethylene oxide (EtO) gas concentrations in ambient air is crucial for regulatory compliance and safeguarding public health. The application of MIR laser technology has enabled significant advancements in this field, offering state-of-the-art capabilities for ultra-precise and stable measurements of EtO gas. This article delves into the features and performance of MIR laser technology, which sets a new standard for real-time monitoring of EtO down to astonishingly low levels, enabling enhanced safety and environmental protection.

MIR laser technology boasts an impressive 0.1 parts-per-billion (ppb) lower limit of detection (LOD) for ethylene oxide. This ensures unparalleled sensitivity. Over an extended period, the technology exhibits peak-to-peak zero drift of less than 0.375 ppb, providing exceptional stability and continuous operation with minimal downtime and data gaps.

MIR laser technology is equipped with advanced components to ensure minimal adsorption and desorption of C2H4O during sample handling. This feature reduces bias and enhances measurement response time to less than 10 seconds, enabling swift and accurate data acquisition. Additionally, the technology incorporates high-precision carbon dioxide (CO2), methane (CH4), water vapor (H2O), and other volatile organic compound (VOC) measurements, ensuring interference-free operation.

MIR laser technology outperforms traditional methods, such as Fourier-Transform Infrared Spectroscopy (FTIR) or Gas Chromatography (GC). The real-time measurements achieved by MIR laser technology, with detection limits as low as 0.06 ppb, ensure prompt event detection and response. Notably, there is no need for zero drift corrections using ultra-high purity gases or cartridges, eliminating the requirement for expensive consumables like liquid nitrogen (N2) to maintain functionality.

MIR laser technology offers easy installation and integration into existing systems, with various data outputs and minimal connections. The technology’s small footprint, low power requirements, and lack of consumables result in cost-effectiveness and increased deployment versatility for various applications.

The application of MIR laser technology represents a significant advancement in ethylene oxide monitoring. With an exceptional detection sensitivity down to 0.1 ppb and impressive stability, MIR laser technology ensures accurate and reliable measurements even at ultra-low concentrations. This cutting-edge technology offers real-time event detection, ease of operation, and cost-effectiveness, making it an invaluable tool for quantification and source determination of ethylene oxide emissions in various industrial, laboratory, and community settings. With MIR laser technology, safety and environmental protection reach unprecedented levels, providing confidence in compliance and proactive measures for a safer and healthier future.

The information provided in this article is for informational purposes only and should not be considered as medical advice. The content is not intended to be a substitute for professional medical diagnosis, treatment, or advice. Always seek the advice of your physician or another qualified healthcare provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read in this article. Reliance on any information provided in this article is solely at your own risk.

Document Date: July 24, 2023