A Comparative Analysis of Sterilization Techniques: Steam, Ethylene Oxide, and Hydrogen Peroxide Plasma

Central sterile supply department

(Adobe Stock 938500017 by PondLord)

Sterilization is a cornerstone of infection control in health care, pharmaceuticals, and research. It ensures the complete elimination of all microbial life, including bacteria, viruses, fungi, and spores, preventing the spread of infections and ensuring the safety of medical procedures.

Choosing the appropriate sterilization method is a complex decision that hinges on several crucial factors, each of which plays a pivotal role in ensuring the effectiveness and safety of the sterilization process. The material composition of instruments is one of the primary considerations, as different materials respond differently to various sterilization methods. For instance, heat- and moisture-resistant instruments, such as metal surgical tools, are well-suited for steam sterilization. In contrast, delicate, heat-sensitive materials like plastics, rubbers, and electronic components require methods such as ethylene oxide (EtO) or hydrogen peroxide (vH₂O₂) plasma sterilization to avoid damage.

Figure 1. Autoclave Sterilization Machine¹

(Image courtesy of Steam.autoclase.com)

Environmental impact also weighs heavily on the decision-making process. Methods like steam sterilization are considered environmentally friendlier due to their use of water and heat, which are naturally occurring and pose minimal harm when disposed of. In contrast, methods such as EtO, while practical, can involve chemicals with a more significant environmental
footprint, necessitating proper handling and disposal to mitigate risks. Facilities are increasingly under pressure to adopt sustainable practices, balancing sterilization effectiveness with eco-friendly considerations.

Safety regulations and standards are critical in determining the best sterilization method. Each sterilization technique must meet specific regulatory requirements set forth by health authorities and organizations such as the FDA, CDC, and Occupational Safety and Health Administration (OSHA). For example, EtO is heavily regulated due to its toxicity and the long cycle times required. Facilities must ensure their sterilization methods fully comply with these regulations to avoid potential health hazards and legal repercussions.

Figure 2. EtO sterilizer⁴

(Image courtesy of Medzell.net)

Operational efficiency is another key factor. In a fast-paced health care environment, sterilization turnaround time can significantly impact the flow of procedures and patient care. Methods like hydrogen peroxide plasma sterilization offer faster processing times, making them ideal for high-demand settings where quick instrument turnover is crucial. However, more complex methods like EtO may require longer cycles, reducing operational efficiency and delaying workflow.

Therefore, choosing the appropriate sterilization method involves balancing the material compatibility of instruments, the process’s environmental footprint, strict compliance with safety regulations, and the need for operational efficiency. By carefully considering these factors, health care facilities can ensure that their sterilization practices are effective and sustainable, providing optimal care while adhering to industry standards.

This article explores 3 widely used sterilization techniques: steam sterilization (autoclaving), EtO sterilization, and vH₂O₂ plasma sterilization. Each method has distinct advantages and limitations, influencing its application in different medical and industrial settings. By comparing their mechanisms, benefits, and regulatory concerns, this analysis aims to help health care facilities and researchers make informed decisions about the best sterilization techniques for their needs.

Steam Sterilization

Steam sterilization, commonly called autoclaving, is one of the most effective and widely used methods (Figure 1). It uses pressurized steam to achieve high temperatures capable of denaturing proteins and effectively killing microorganisms. Autoclaves operate under different cycles depending on load type, temperature, and exposure time. The most common parameters include:

Gravity displacement cycle: Used for heat- and moisture-stable items at 121°C (250 °F) for 30 minutes

Prevacuum cycle: More efficient for porous materials at 132 °C (270 °F) for 4 minutes

Flash sterilization: For urgent or quick turnaround situations at 132 °C (270 °F) for 3 minutes

Fun fact: The term autoclave comes from the Greek words auto (“self”) and clave (“locking or closing”), referring to its self-locking, high-pressure chamber that ensures complete sterilization.

Pros:

• Highly effective for heat- and moisture-resistant instruments
• Cost-efficient and widely available
• No toxic residues or harmful emissions

Cons:

• Not suitable for heat-sensitive instruments
• It can cause corrosion or material degradation over time
• It requires drying time to prevent wet loads

EtO Sterilization

EtO sterilization is a low-temperature method that uses EtO gas to eliminate microorganisms, making it particularly suitable for heat-sensitive medical devices and equipment (Figure 2). However, due to the toxic and carcinogenic nature of EtO, strict safety measures must be in place, including proper aeration to remove residual gas, protective equipment for personnel, and continuous monitoring for leaks in well-ventilated areas.

Comparison Chart

a. Environmental Protection Agency; Occupational Safety and Health Administration.

Although effective, EtO poses environmental concerns, as it is a volatile organic compound that contributes to air pollution. Many facilities implement emission control measures such as catalytic oxidation, and increasing regulatory scrutiny has prompted the search for alternative sterilization methods. The OSHA and the Environmental Protection Agency have imposed strict guidelines on EtO usage due to its potential health risks.²

The FDA recommends a transition from EtO to alternative sterilization methods, but it offers many advantages not shared by other low-temperature sterilization technologies, such as:

• Broad material compatibility
• Ability to penetrate medical packaging (including cardboard)
• Chamber that accommodates large quantities (many pallets)
• Capability to reach difficult locations (eg, device lumens)

Fewer than 55,000 medical devices have been cleared for EtO, slowing the transition to other low-temperature sterilization methods. With the exception of radiation, other low-temperature sterilization technologies have been FDA-cleared for fewer than 50 single-use, sterile items.³

Regulations and Challenges in California

EtO sterilization is highly regulated in California due to its carcinogenic and environmental risks. The state enforces strict emission limits, permitting requirements, and worker safety regulations, making compliance challenging for facilities. Many health care providers are transitioning to alternative methods, like hydrogen peroxide gas plasma, to meet safety and environmental standards.

Pros:

• Suitable for heat- and moisture-sensitive instruments
• Highly effective at eliminating a broad range of microorganisms
• It can sterilize complex and delicate medical devices

Cons:

• Long sterilization cycle (12+ hours).
• Toxic residues require extensive aeration
• High regulatory scrutiny and environmental concerns

Figure 3. vH₂O₂ Plasma Sterilization⁵

(Image courtesy of Nelsonlabs.com) 

Hydrogen Peroxide Plasma Sterilization

vH₂O₂ plasma sterilization is another low-temperature technique that uses vaporized hydrogen peroxide and plasma to sterilize medical instruments and materials (Figure 3). This method offers several advantages, including a fast sterilization cycle typically completed within 45 to 75 minutes, no toxic residue because vH₂O₂ decomposes into water and oxygen, and compatibility with heat- and moisture-sensitive instruments.

However, it has some limitations, such as incompatibility with cellulose-based materials or liquids, size restrictions due to limited chamber capacity, and higher costs associated with initial investment and maintenance.⁶ vH₂O₂ plasma sterilization is ideal for sterilizing complex surgical instruments, disinfecting endoscopes, and environments requiring rapid turnaround for sterilized equipment.

Pros:

• Fast cycle time compared with EtO
• No toxic residues, making it environmentally friendly
• Effective for heat-sensitive instruments and electronics

Cons:

• Not compatible with cellulose-based materials or liquids
• Limited chamber size restricts extensive equipment sterilization
• Higher cost of equipment and maintenance

Best Sterilization Method and Opinion

The best sterilization method depends on various factors, including the type of instrument, material compatibility, turnaround time, and regulatory considerations. Steam sterilization is the gold standard for instruments that can withstand heat and moisture. It is highly effective, cost-efficient, and environmentally friendly, ideal for surgical tools, metal instruments, and reusable hospital equipment. EtOsterilization is essential for heat-sensitive and complex medical devices such as endoscopes, catheters, and electronics. Although it has a long cycle and presents regulatory challenges, its superior penetration and material compatibility make it indispensable for intricate instruments. vH₂O₂ plasma sterilization offers a fast, residue-free alternative for heat-sensitive materials, making it ideal for delicate surgical equipment, cameras, and electronics that cannot withstand high temperatures or moisture.

Given the increase in noninvasive surgeries requiring cameras and robotic instruments, more and more facilities will use vH₂O₂ plasma sterilization for these heat-sensitive materials. Overall, steam sterilization is the best choice for general hospital use. EtO is necessary for complex and heat-sensitive devices, and vH₂O₂ plasma provides a faster, cleaner option for specific materials.

Conclusion

Each sterilization method has its strengths and limitations. Steam sterilization remains the gold standard for heat-resistant instruments due to its reliability and cost-effectiveness. EtO sterilization is indispensable for heat-sensitive equipment but has significant safety and environmental concerns. vH₂O₂ sterilization provides a rapid, residue-free alternative but is constrained by material compatibility and cost. Facilities must carefully assess their sterilization needs to select the most appropriate method for ensuring patient safety and compliance with regulatory standards.

Given the array of available sterilization methods, health care facilities must carefully assess their unique needs to select the most appropriate method. This involves considering the type of instruments being sterilized, the required turnaround times, the available resources, and the potential impact on patient safety. Infection control plays a critical role in this decision-making process, as ensuring the sterility of medical instruments directly impacts the prevention of health care-associated infections. Infection control professionals evaluate sterilization methods from both a clinical and safety standpoint, ensuring that they meet regulatory standards and minimize the risk of infection transmission to patients.

Infection control teams must stay informed about the latest advancements in sterilization technologies, assess the effectiveness of current sterilization practices, and provide guidance to health care staff on best practices. Overall, selecting the proper sterilization method is essential for ensuring patient safety, reducing the risk of infections, and maintaining compliance with health regulations. This collaborative effort involves a thorough understanding of each method’s strengths and limitations, along with a focus on infection prevention and control. 

References

1. Pulse Vacuum Steam Sterilizer Hinged Door Autoclave Sterilization Machine. Accessed March 20, 2025. https://m.steam-autoclave.com/pid18365259/Pulse-Vacuum-Steam-Sterilizer-Hinged-Door-Autoclave-Sterilization-Machine.htm.
2. Ethylene oxide: health risks and safety guidelines. Occupational Safety and Health Administration. 2021.
3. Rutala WA, Weber DJ. Sterilization of 20 billion medical devices by ethylene oxide (ETO): Consequences of ETO closures and alternative sterilization technologies/solutions. Am J Infect Control. 2023;51(suppl 11):A82-A95. doi:10.1016/j.ajic.2023.01.020​
4. Cistron Systems. EO-Matic ETO Sterilizers. Medzell. Accessed March 20, 2025. https://www.medzell.net/product/eo-matic-eto-sterilizers-from-cistron-systems/.
5. Nelson Labs. Sterilization Validation - VHP. Accessed March 20, 2025. https://www.nelsonlabs.com/testing/sterilization-validation-vhp/.
6. Rutala WA, Weber DJ. Guidelines for sterilization in healthcare facilities. Infect Control Hosp Epidemiol. 2019. Accessed March 20, 2025. https://pmc.ncbi.nlm.nih.gov/articles/PMC7134755/