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Chemical Sterilization: Formaldehyde and Peracetic Acid for Effective Infection Prevention

In the dynamic world of sterilization, the use of chemicals plays a crucial role, especially for materials that are sensitive to heat and moisture. Among these chemical methods, Formaldehyde and Peracetic Acid are renowned for their broad-spectrum efficacy and adaptability. This guide explores the inner workings, applications, benefits, and safety protocols of these sterilants.


Chemical Sterilization Demystified

Chemical sterilization employs potent agents, notably Formaldehyde and Peracetic Acid, to obliterate microbial life. This method is pivotal across various sectors such as healthcare, laboratory sciences, and food processing for its unparalleled ability to secure sterility. By disrupting vital cellular functions, chemical sterilization ensures comprehensive decontamination, even in the most intricate environments.


Formaldehyde Sterilization

Formaldehyde sterilization uses gaseous Formaldehyde to purge microbial contaminants. It stands out for its strong antimicrobial prowess, targeting the amino and sulfhydryl groups in proteins and nucleic acids, effectively neutralizing microorganisms.

It is crucial to choose the right packaging for all sterilization methods.

Process Overview

  1. Initial vacuum is applied to remove air from the sterilization chamber and the load.

  2. Steam is injected into the chamber, heating the load to the desired temperature between 60-80°C

  3. Formaldehyde gas is then introduced into the chamber, mixing with the steam. A high concentration of formaldehyde gas, typically 8-16 mg per liter, is used

  4. The formaldehyde gas exposure is maintained, with a relative humidity of 75-100%, to ensure reliable sterilization.

  5. After the sterilization cycle is complete, the formaldehyde residues are removed by repeated evacuations and flushing with steam and air.

  6. The sterilized materials are then ready for use without the need for additional ventilation.


  • Surgical Instruments: Ideal for materials that can't withstand high temperatures, ensuring tools are free of pathogens before procedures.

  • Endoscopes: Used for delicate instruments involved in internal examinations, where sterility is critical.

  • Dental Equipment: Sterilizes instruments that come into close contact with mucus membranes, preventing cross-contamination.

  • Ventilation Systems: Applied in air ducts and HVAC systems in hospitals to reduce airborne pathogens, improving indoor air quality for patients and staff.

A CSSD (Central Sterile Services Department)


Peracetic Acid Sterilization

Leveraging Peracetic Acid, in liquid or vapor form, this sterilization method employs a potent oxidizing agent for microbial elimination. The oxidative destruction of cell components by Peracetic Acid is swift, rendering it an efficient sterilant.

Process Overview

Introduced in 1988, an automated machine using Peracetic Acid for sterilizing medical, surgical, and dental instruments represents a significant advancement. The process involves diluting concentrated Peracetic Acid to 0.2% with filtered water, circulating this solution to decontaminate instruments effectively. This method is highly effective against a broad spectrum of microorganisms, including bacteria, fungi, yeasts, and viruses, in significantly short contact times.


  • Medical Devices: Effective for sterilizing complex instruments, including those with lumens and intricate parts, without leaving harmful residues.

  • Surgical Gowns and Drapes: Sterilizes fabrics used in surgery to maintain a sterile field, reducing infection risks.

  • Dialysis Units: Used for sterilizing equipment in nephrology departments to prevent infections in patients with kidney failure.

  • Laboratory Equipment: Ensures sterility of lab instruments used in diagnostic and research applications, critical for accurate results.


Comparing Formaldehyde and Peracetic Acid Sterilization


Formaldehyde Sterilization

Peracetic Acid Sterilization

Antimicrobial Activity

Potent antimicrobial activity against a broad range of pathogens.

Potent antimicrobial activity against a broad range of pathogens.

Material Compatibility

Broad material compatibility, with considerations for potential material sensitivity.

Broad material compatibility, suitable for a wide variety of materials.

Temperature Requirements

Requires higher temperatures for effective sterilization.

Effective at lower temperatures, making it suitable for heat-sensitive materials.

Processing Times

Can require longer processing times due to the nature of the sterilization process.

Offers rapid action, resulting in shorter processing times.

Safety Profiles

Poses greater health risks, requiring strict safety protocols.

Lower toxicity, making it safer for operators and potentially reducing environmental impact.

Preferred Applications

Widely used across various applications, with precautions due to safety concerns.

Preferred for certain applications, especially in healthcare, due to rapid action and lower toxicity.


Advantages of Chemical Sterilization

Chemical sterilization offers several advantages over traditional heat-based methods, including:

  • Lower Temperature Requirements: They stand as the go-to option for sterilizing heat-sensitive items, safeguarding material integrity.

  • Broad-Spectrum Efficacy: Their ability to neutralize a wide array of pathogens ensures comprehensive sterilization.

  • Ease of Use: These methods adeptly handle complex equipment and objects with irregular shapes, providing flexibility in application.

  • Minimal Residue Formation: This characteristic significantly cuts down on the need for post-sterilization cleaning, streamlining the sterilization process.


Safety and Environmental Considerations

The deployment of chemical sterilants mandates rigorous adherence to safety protocols to protect personnel and the environment from potential hazards. Ensuring adequate ventilation, donning appropriate personal protective equipment (PPE), and adhering to stringent waste disposal guidelines are paramount for safe and responsible use.

Regulatory Compliance and Best Practices

Upholding standards set by authoritative bodies such as the FDA and EPA is crucial for maintaining operational excellence and public safety. Compliance with these regulations reinforces the commitment to quality care and environmental stewardship. Best practices encompass comprehensive training for personnel, regular equipment maintenance, and documentation of sterilization processes for accountability and traceability.


Future Trends and Innovations

The future of chemical sterilization is marked by promising developments in sterilant formulations, equipment design, and process automation. Innovations aimed at enhancing sterilization efficiency, reducing environmental impact, and improving safety standards are expected to drive the evolution of chemical sterilization technologies.



Formaldehyde and Peracetic Acid sterilization methods are indispensable tools in the sterilization arsenal, offering effective solutions for ensuring the sterility of sensitive equipment. By adhering to best practices and regulatory guidelines, professionals can leverage these chemical sterilization methods to maintain high standards of cleanliness and safety.

As we navigate the future of sterilization technologies, rely on our Formaldehyde-compatible packaging solutions to uphold high standards of cleanliness and safety, ensuring effective sterilization and protection for sensitive equipment.


Frequently Asked Questions (FAQs)

Q: How do Formaldehyde and Peracetic Acid sterilize differently?

A: Formaldehyde sterilizes by alkylating microorganisms' DNA and proteins, whereas Peracetic Acid oxidizes cell components, leading to cell death. Each has unique advantages and applications based on their action.

Q: Are there materials that shouldn't be sterilized with Formaldehyde or Peracetic Acid?

A: Yes, certain materials may be sensitive to these chemicals. Formaldehyde can damage some plastics and rubber, while Peracetic Acid may corrode certain metals. Always consult compatibility guides before sterilization.

Q: What are the main safety concerns with chemical sterilization?

A: Chemical sterilization can pose health risks through exposure to toxic agents, requiring proper PPE, ventilation, and adherence to safety protocols to mitigate these risks.

Q: How does environmental impact compare between Formaldehyde and Peracetic Acid sterilization?

A: Formaldehyde has more significant environmental and disposal concerns due to its toxic nature. Peracetic Acid breaks down into water and oxygen, presenting less environmental impact.

Q: What future trends are shaping chemical sterilization?

A: Future trends include developing safer, more efficient sterilants, and technologies to reduce environmental impact, enhance sterilization efficacy, and improve user safety.



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