The dangers of hydrogen peroxide in sterilization and bio-decontamination

Hydrogen peroxide is a colorless liquid, often available in aqueous solutions. It originated from the reaction of barium peroxide with nitric acid devised by the chemist Louis Jacques Thénard in 1818. It was subsequently improved with hydrochloric acid and then with sulphuric acid.

The disinfectant properties of hydrogen peroxide make it a product frequently used in the medical or pharmaceutical industry. Hydrogen peroxide allows answering the need for reusable instruments sterilization and bio-decontamination necessity in research laboratories and drug production facilities. However, using this chemical element involves some hazards and requires gas detection and respiratory protection equipment.

To ensure care, avoid infections, and prevent cross-contamination, sterilization of care equipment is essential in the medical world. Disinfection of reusable medical equipment is carried out by water vapor or hydrogen peroxide. The technique using H2O2 is commonly used when using an autoclave (pressurized hermetic chamber with water vapor) at high temperatures can damage the material to be sterilized, such as plastic or some complex or fragile medical tools. For example, hydrogen peroxide disinfection is used for catheters, endoscopes, and surgical instruments.

The hydrogen peroxide sterilization technique is performed at cold and low pressure by exposing the medical equipment to this gas. Cleaning medical instruments using a plasma sterilizer destroys infectious agents quickly and easily (approximately 1 to 2 hours following the equipment). The instruments to be disinfected are placed in a vacuum chamber and then subjected to vaporized or gaseous H2O2. A hydrogen peroxide plasma phase is generated by an electromagnetic field. It is during this reaction that the bacterial cells are destroyed and the instruments are completely sterilized. After ventilation, the chamber can finally be opened and the sterilized material can be reused.

H2O2 can also be helpful for bio-decontamination in the pharmaceutical industry. For numerous pharmaceutical applications (research, manufacturing, control, etc.) contamination risk control is a crucial issue. These activities, such as manufacturing sterile drugs, for example, require clean room implementation referenced to the ISO 14644 standard. Therefore, the pharmaceutical industry operates controlled-atmosphere zones (CAZs), necessitating the control of microbial contamination risks and bio-decontamination processes. These include drug manufacturing workshops, stability chambers, clean rooms, transfer rooms, isolators, and some warehouses.*

If the principle of disinfection with gas is known since antiquity (sulphur, arsenic, hydrochloric acid), and after operating different gases such as ethylene oxide (ETO) or formaldehyde, today the pharmaceutical industry prefers hydrogen peroxide for the bio-decontamination processes of clean areas. Not only is this substance disinfectant, but food-grade H2O2 is also the most economical and environmentally friendly of all cleaning materials.

The sterilization of clean rooms is carried out by hydrogen peroxide fumigation, by vaporization of H2O2, or by dispersion of a solution in aerosol droplets of H2O2. Rigorous cleaning of areas with a disinfectant liquid is essential. Hygiene measures involve treating a room with automatic disinfection machines to destroy all strains of microbial and bacterial contamination present in a room, thereby decontaminating the entire environment. Airborne decontamination processes rely on high concentrations of hydrogen peroxide (up to 35%) in a room and must be carried out in a closed area without any staff present.

Hydrogen peroxide, CAS 7722-84-1, also known as hydrogen peroxide, is widely used in the medical and pharmaceutical industries. H2O2 is a toxic, corrosive, and oxidizing element. Its corrosive and toxic characteristics make it an excellent biocide for sterilization and bio-decontamination. Medical and pharmaceutical sectors use hydrogen peroxide, notably for its oxidizing properties, which enable it to act as an antiseptic. It is also used in the food industry (packaging sterilization), water treatment, and paper industry (pulp bleaching).French health authorities fixed a 1ppm OELP (8-hour occupational exposure limit value) in order to protect workers from these dangerous gas properties.

The use of hydrogen peroxide in the medical and pharmaceutical industries represents a danger for the many professionals working in these fields. The exploitation of oxygenated liquid as a sterilizing and bio-decontaminating agent can involve chronic or accidental acute exposure to dangerous concentrations of this gas. Malfunctioning or mishandling of machinery, non-compliance with safety procedures, or mishandling of H2O2 solutions can lead to gas leakage and hazardous health effects on people.

Chronic exposure to low concentrations of H2O2 will cause skin irritation, hair whitening, and respiratory tract irritation. Presentation to high concentrations may cause significant inhalation of hydrogen peroxide vapors, resulting in severe respiratory distress, loss of consciousness, or fatal systemic poisoning.

In the face of the dangers of hydrogen peroxide, safety measures must be implemented in the medical and pharmaceutical environments using this gas.

Among these safety measures, the detection and monitoring of concentrations of this gas is an indispensable action. Various measurement solutions are used for this purpose:

• The portable H2O2 detector: mobile and practical, a portable hydrogen peroxide detector like the X-am 5100 or the WatchGas PDM+ immediately alerts its wearer to whatever the danger is. The Portasens III detector, with its sampling probe and interchangeable sensors, enables ultra-precise measurement of concentrations and localization of leaks on sterilization equipment.
• Fixed hydrogen peroxide detectors: ideal for monitoring bio-decontamination processes in the pharmaceutical industry, a fixed B12 detector for safe area installed in the treatment room and connected to a gas controller outside the room, guarantees continuous monitoring of gas concentration. For ATEX zones, KwikSente Lite and KwikSense Pro (SIL2) is preferred. 
• Colorimetric reagent tubes: inexpensive and easy to use, they help to quickly measure the concentration of these substances after a decontamination process, for example, to clear up any doubts before entering a treated room. Whether it's Gastec reagent tubes or Dräger tubes, colorimetric tubes are precise, economical devices that require no special skill.
• Gas detectors equipped with a sampling pump: Strongly appreciated by the industry, laboratories, water treatment, pollution control sites, and the semiconductor industry. The SI-H100 gas detector with an integrated sampling pump captures and analyzes toxic substances up to 30 meters away.

In addition to detection equipment, if employees have to work in environments with high concentrations of hydrogen peroxide, they must be equipped with respiratory protection products. This equipment is an essential element in protecting the health of users, and can be adapted to suit different exposure situations:

• We might use in work situations an air-supply system or device to ensure a constant flow of healthy breathing air to personnel
• For emergencies involving H2O2, responders must wear a self-contained breathing apparatus (SCBA)
• Finally, self-rescue masks must be available in high-risk areas for emergency evacuation equipment

Other category 3 personal protective equipment includes HAZMAT suits (CHEM1, CHEM3, CPS 5800), chemical protective clothing. This professional equipment contains resistant materials that isolate the body to prevent any contact with the hazardous product.