Protecting Workers from the Dangers of Ethylene Oxide

Introduction

Ethylene oxide (C₂H₄O) is a flammable gas with a slightly sweet odor that plays a crucial role in many industries. Despite its importance, ethylene oxide is a hazardous substance that can cause a range of health issues depending on the extent of exposure. This article will explore ethylene oxide’s history, its applications, health effects, regulations, and measures that can be taken to protect workers.

What is Ethylene Oxide?

Ethylene oxide is an organic compound that is a cyclic ether and the simplest epoxide. It consists of a three-membered ring with one oxygen atom and two carbon atoms. Its reactivity and ability to participate in various reactions make it useful in producing many consumer and industrial products.

Ethylene Oxide’s History

French chemist Charles-Adolphe Wurtz first reported ethylene oxide in 1859. However, it was not until 1931 that Theodore Lefort developed a method for directly oxidizing ethylene, which has become the primary industrial production process. Ethylene oxide gained importance during World War I as a precursor for coolant ethylene glycol and the chemical weapon mustard gas. Its use as a sterilizing agent began in the 1940s, when researchers discovered its efficacy in killing microorganisms, including spores, bacteria, and viruses. This discovery revolutionized the medical and pharmaceutical industries by providing a means to sterilize heat-sensitive equipment and materials, such as surgical instruments, syringes, and catheters. Over the years, ethylene oxide has become an essential chemical in various industries, such as the production of detergents, surfactants, and polyurethane foams. As the demand for and applications of ethylene oxide expanded, awareness of its potential hazards to human health and the environment grew, prompting the development and implementation of stringent regulations and guidelines to ensure its safe usage and minimize its impact.

Industrial Applications

Ethylene oxide is used in a wide range of industries to produce products such as solvents, antifreeze, textiles, detergents, adhesives, and polyurethane foam. It is also used in the production of ethylene glycol, ethanolamines, glycols, polyglycol ethers, and other compounds.

Ethylene Oxide in the Medical Industry

In the medical field, ethylene oxide serves as a surface disinfectant, replacing steam for sterilizing heat-sensitive tools and equipment. It is commonly used in hospitals and the medical equipment industry.

Ethylene Oxide in Agriculture

Farm workers may use ethylene oxide to control insects in grain bins, protecting crops from damage.

Notable Accidents

The La Canonja Accident was an accident that took place on January 14, 2020. An ethoxylation reactor owned by IQOXE, part of the CL Industrial Group, exploded at an industrial estate near Tarragona, Spain. This explosion sent debris flying over a 2.5-kilometer radius, with one chunk even penetrating a home and killing someone inside. The blast directly caused at least three fatalities and injured seven others. Before the explosion, IQOXE was Spain’s sole ethylene oxide producer, boasting an impressive 140,000 tons per year capacity. Half of their production went into making ethylene glycol for PET production. The European Agency for Safety and Health at Work investigated the accident under EU regulations.

The 2020 Indian Sesame Seed Contamination was an invent that occured in September of that year, a whopping 268 tonnes of sesame seeds from India were found to have sky-high levels of pesticides – 1,000 to 3,500 times the EU limit of 0.05 milligrams per kilogram for ethylene oxide, a known carcinogen and mutagen. It’s worth noting that this pesticide is actually banned in Europe. A product recall was initiated, and it’s worth mentioning that half of the affected products had an organic certification. Belgium raised the alarm through RASFF, but the contaminated sesame seeds had already been sold in other EU countries like France and Ireland.

Health Effects of Ethylene Oxide

Exposure to ethylene oxide can cause headaches, nausea, vomiting, diarrhea, difficulty breathing, drowsiness, weakness, fatigue, eye and skin burns, frostbite, and reproductive problems. The extent of harm depends on the concentration, duration of exposure, and the worker’s activities. Long-term exposure to low levels of ethylene oxide has been associated with an increased risk of cancer, particularly leukemia and lymphoma, as well as neurological and immune system disorders. Workers in industries utilizing ethylene oxide, such as sterilization facilities and chemical plants, are at a higher risk of exposure and must adhere to strict safety measures and protocols to minimize their risk. Moreover, ethylene oxide’s potential to contaminate air, soil, and water sources highlights the importance of environmental monitoring and mitigation strategies. Public health organizations, such as the World Health Organization (WHO) and the United States Environmental Protection Agency (EPA), have classified ethylene oxide as a human carcinogen and continue to conduct research to better understand its effects on human health and develop strategies to protect workers and the general population from its harmful consequences.

Skin Irritation

Ethylene oxide can penetrate through clothing and footwear, causing skin irritation and dermatitis, as well as blisters, fever, and leukocytosis.

Carcinogenic Effects

The International Agency for Research on Cancer (IARC) classifies ethylene oxide as a Group 1 carcinogen, meaning it is a proven carcinogen. Chronic exposure to the chemical has been linked to increased risks of certain cancers, such as breast cancer and lymphoid tumors. Studies have shown that occupational exposure to ethylene oxide can result in increased incidences of these cancers among workers, particularly those involved in the sterilization of medical equipment, manufacturing of chemicals, and pesticide production. The carcinogenic potential of ethylene oxide is believed to be due to its ability to form DNA adducts, which are molecular lesions that can lead to genetic mutations and, ultimately, the development of cancer. The identification of ethylene oxide as a carcinogen has led to increased efforts to minimize occupational and environmental exposure, implement stricter safety guidelines, and develop alternative sterilization methods and industrial processes. Public health authorities and organizations continue to monitor and assess the risks associated with ethylene oxide exposure, aiming to protect workers and communities from its carcinogenic effects.

Acute Poisoning

Ethylene oxide can cause acute poisoning, with symptoms including central nervous system effects like headache, nausea, and vomiting. Prolonged exposure may lead to peripheral neuropathy, impaired hand-eye coordination, and memory loss.

First Aid

Eye exposure:

If Ethylene oxide splashes into your eyes, flush them with plenty of water, lifting both lower and upper eyelids.
Seek medical help right away.
Remember, don’t wear contact lenses when working with Ethylene oxide

Skin exposure:

If Ethylene oxide touches your skin, wash the area with water immediately.
If it soaks through clothes, especially shoes, remove them right away and use an emergency deluge shower.
Get medical help without delay.
Wash contaminated clothes thoroughly before reusing.
Toss out contaminated leather items like shoes; don’t reuse them.

Inhalation:

If you breathe in a lot of Ethylene oxide, get to fresh air immediately.
Perform CPR if the person isn’t breathing.
Keep the person warm and resting.
Seek medical help ASAP.

Swallowing:

If someone swallows Ethylene oxide, have them drink lots of water.
After that, try to induce vomiting by touching the back of their throat.
Never try this with an unconscious person.
Get medical help right away.

Rescue:

Move the affected person away from the hazard.
Inform at least one other person of the emergency and initiate established emergency procedures.
Don’t put yourself in danger; know your emergency rescue procedures and equipment locations beforehand.

Toxicity and Exposure Limits

Ethylene oxide is toxic by inhalation, with the US Occupational Safety and Health Administration (OSHA) setting permissible exposure limits at 1 ppm over an 8-hour time-weighted average and 5 ppm over a 15-minute short-term exposure limit. The National Institute for Occupational Safety and Health (NIOSH) has determined that an immediately dangerous to life and health level (IDLH) is 800 ppm. These exposure limits are put in place to protect workers from the potential acute and chronic health effects associated with ethylene oxide exposure, which can range from respiratory irritation and central nervous system effects to the aforementioned carcinogenic risks. Industries that use or manufacture ethylene oxide are subject to these regulations and must adhere to them to ensure worker safety.

Environmental Exposure Limits to Protect the General Public

In addition to workplace exposure limits, regulatory agencies have also established environmental exposure limits for ethylene oxide to protect the general public. The US Environmental Protection Agency (EPA) has set an annual average guideline concentration of 0.0005 ppm to protect the public from chronic, non-cancer health effects. This limit is significantly lower than the OSHA standards for occupational exposure, reflecting the need to protect vulnerable populations, such as children and the elderly, who may be more sensitive to the toxic effects of ethylene oxide. Moreover, the EPA has also established guidelines for ethylene oxide emissions from industrial sources to minimize its presence in the environment and reduce the risk of exposure to nearby communities. These guidelines include air pollution control measures, monitoring requirements, and reporting obligations for facilities that emit ethylene oxide.

Odor Threshold and Monitoring

While the odor threshold for ethylene oxide ranges from 250 to 700 ppm, it’s important to note that this range is well above the permissible exposure limits set by regulatory agencies. As a result, relying on smell alone to detect ethylene oxide is not an effective safety measure. To protect workers from hazardous exposure, many workplaces implement continuous electrochemical monitoring systems. These systems can detect even trace amounts of ethylene oxide in the air, alerting workers and supervisors to potential leaks or elevated concentrations before they reach harmful levels. Regular maintenance and calibration of these monitoring systems are crucial to ensure accurate readings and maintain a safe working environment for everyone.

Regulations and Guidelines

Ethylene oxide has been subject to a variety of regulations and guidelines worldwide, which aim to protect both workers and the environment from the potential hazards associated with its use. These regulations help ensure that the industries utilizing ethylene oxide take the necessary precautions to prevent harmful exposure to their employees and minimize environmental impact.

In the United States, the Occupational Safety and Health Administration (OSHA) sets permissible exposure limits (PELs) for various substances, including ethylene oxide. The PEL for ethylene oxide is currently set at 1 part per million (ppm) as an 8-hour time-weighted average (TWA) and a short-term exposure limit (STEL) of 5 ppm as a 15-minute TWA. This means that workers should not be exposed to concentrations above these limits during their work shift.

The National Institute for Occupational Safety and Health (NIOSH) provides additional recommendations for safe handling of ethylene oxide. NIOSH suggests employers implement the Hierarchy of Controls, which consists of elimination, substitution, engineering controls, administrative controls, and personal protective equipment (PPE) to minimize worker exposure.

Engineering controls include proper ventilation systems, closed-loop systems, and leak detection equipment to minimize the potential for ethylene oxide exposure. Administrative controls involve implementing standard operating procedures, worker training, and exposure monitoring to ensure workers understand the risks associated with ethylene oxide and follow the appropriate safety protocols. Personal protective equipment, such as chemical-resistant gloves, protective clothing, and respiratory protection, should be provided and worn by workers when necessary.

The Environmental Protection Agency (EPA) also regulates the release of ethylene oxide into the environment. Under the Clean Air Act, the EPA sets emission standards for various industries that use or produce ethylene oxide. Facilities must adhere to these standards to minimize the release of ethylene oxide into the atmosphere and protect the surrounding environment and communities.

Internationally, regulations may vary from country to country. The European Union’s REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulation requires companies to register and provide information on the properties and uses of the substances they manufacture or import. This data is used to evaluate the potential risks associated with the substance and determine appropriate risk management measures, including exposure limits and safety precautions for workers.

Workplace Safety Measures

To protect workers from the potential hazards of ethylene oxide exposure NIOSH recommends that employers use the Hierarchy of Controls to prevent injuries, which is a combination of engineering, administrative, and PPE controls. The hierarchy of controls is a vital framework for controlling hazards in the workplace and protecting workers. It comprises five levels of actions to reduce or remove hazards, in order of general effectiveness:

Elimination: Removes the hazard at the source, preventing any exposure. It is the preferred solution and is most effective during the design or development stage of work processes or when selecting new equipment or procedures.
Substitution: Replaces the hazardous source with a safer alternative, such as using plant-based printing inks instead of solvent-based inks. It is important to evaluate the potential risks of the substitute and ensure it does not introduce new hazards.
Engineering Controls: Focuses on reducing or preventing hazards from coming into contact with workers. Effective engineering controls are part of the original equipment design, remove or block hazards at the source, require minimal user input, and operate correctly without interfering with the work process.
Administrative Controls: Establishes work practices to reduce the duration, frequency, or intensity of exposure to hazards. This includes work process training, job rotation, adequate rest breaks, and limiting access to hazardous areas or machinery.
Personal Protective Equipment (PPE): Minimizes exposure to hazards through the use of equipment such as gloves, safety glasses, and respirators. PPE should not be relied upon as the sole control method but is necessary when other controls cannot reduce hazardous exposure to safe levels or are under development.

Employers should train workers and supervisors on the correct use of controls and evaluate their effectiveness regularly to ensure the success of the selected controls and identify potential improvements.

The following are some key measures to be taken in the workplace, and these are practical examples of how to implement the Hierarchy of Controls:

Regular inspection and maintenance of equipment and storage systems to prevent leaks and spills.
Installation of proper ventilation systems to remove ethylene oxide from the air and maintain safe concentration levels.
Implementation of closed-loop systems for processes involving ethylene oxide to minimize the potential for worker exposure.
Training programs for employees to ensure they understand the risks associated with ethylene oxide and the necessary safety precautions.
Strict adherence to exposure limits set by regulatory agencies, such as OSHA and NIOSH.
Monitoring of worker exposure levels to ensure compliance with established limits and identification of potential issues.
Provision of appropriate personal protective equipment, including chemical-resistant gloves, protective clothing, and respiratory protection, when necessary.
Development and implementation of emergency response plans in case of accidental releases or exposure incidents.
Regular review and updating of safety protocols and procedures to ensure ongoing compliance and effectiveness.

In conclusion, ethylene oxide is a valuable industrial chemical with a wide range of applications. However, its potential hazards to human health and the environment necessitate strict adherence to regulations and guidelines, as well as the implementation of appropriate safety measures in the workplace. By doing so, industries can continue to benefit from the many uses of ethylene oxide while protecting workers and minimizing the environmental

Selected Publications as Recommended by NIOSH:

Preventing Worker Injuries and Deaths from Explosions in Industrial Ethylene Oxide Sterilization Facilities—DHHS (NIOSH) Publication No. 2007-164. This Alert focuses on the explosions, injuries, and deaths that can happen at ethylene oxide sterilization facilities and repackaging plants. It gives steps to prevent explosions.
Control Technology for Ethylene Oxide Sterilization in Hospitals —DHHS (NIOSH) Publication No. 89-120 (1989). This historic report looks at systems that use ethylene oxide to kill germs in hospitals and ways to prevent workers from being exposed.
Ethylene Oxide Sterilizers in Health Care Facilities—Engineering Controls and Work Practices—DHHS (NIOSH) Publication No. 89-115 (1989). This historic report looks at sources of ethylene oxide exposure and recommends how to protect hospital workers.
Occupational Safety and Health Guideline for Ethylene Oxide— DHHS (NIOSH) Publication No. 81-123 (1988). This historic guideline has information for workplace safety and health programs.
Ethylene Oxide: Evidence of Carcinogenicity—DHHS (NIOSH) Publication No. 81-130 (1981). This historic report focuses on information about the ability of ethylene oxide to cause cancer.

Related Resources as Recommended by NIOSH: