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EFFECTIVE H202 DECONTAMINATION MONITORING FOR INFECTION CONTROL & STAFF SAFETY

Environmental deep-cleaning and decontamination are crucial to the prevention and control of infection within hospital and healthcare facilities. Pathogens, such as Coronavirus, can be easily spread from infected patients through cross-contamination and it is possible for them to survive on surfaces for weeks.

Hydrogen peroxide decontamination procedures, known as ‘fogging’, by fully qualified, specialist companies, are essential to disinfect rooms and equipment to help infection prevention and control.  However, how can it be proven that these decontamination processes have been a success?  And how can it be proven that no toxic gases remain, eliminating serious health risks of keyworkers and patients?

Hydrogen Peroxide

Hydrogen peroxide (H2O2) is an extremely strong oxidiser, widely used in the decontamination of medical, education, leisure and care facilities. Once the vapour comes into contact with these organisms, it will destabilise any molecule by destroying its DNA.

The last SARS outbreak in 2003 was successfully extinguished with 35% hydrogen peroxide. Although other gases can kill such viruses, this strong mix of H2O and O2 is the most effective to date, when compared to alternative oxidising AND alkylating agents, with the most efficient systems and the safest outcomes.

Many facilities use equipment or have areas that require continuous sterilisation or regular decontamination, and hydrogen peroxide is used because of its effectiveness in killing bacteria and microbes.  However, hydrogen peroxide is also a high strength oxidant and is dangerous to all living cells.

The decontamination of an area needs to be a well-calculated exercise as H202 target rates are critically important. If there are weaknesses in the planning of this important task, the risks of a ‘dirty’ room after cleaning can lead to the infection of both patients and medical staff.

The only way to ensure the safety of staff and patients within these departments is to monitor and alarm where toxic gas levels exceed that of the exposure guidelines, by using fixed or portable detection systems with a reliable and accurate hydrogen peroxide sensor.

Deep-cleaning – Staff Safety

The Coronavirus pandemic has resulted in a multitude of newcomers to the disinfection market, with a wide variety of fogging devices being used.  Care must be taken when working with these new ‘fogging’ companies, due to their inexperience when calculating HAZOP the strength of sterilant used. A specific ‘log reduction’ is required when performing decontamination of an area. The strength of a detergent may be one thing on a hard surface, but this same level isn’t as effective when sprayed into the air. If there are mistakes made with misunderstanding the amount of ‘contact time’ required to complete a successful kill, or more importantly the time it takes to allow staff and patients to re-enter the room ‘post fogging’, there can be dangerous consequences.

This dangerous false perception of safety is often down to companies misunderstanding the strength of a sterilant, versus the required log reductions.  Using a 35% strength hydrogen peroxide chemical as a liquid will achieve a higher kill-rate when poured directly onto organisms, when compared to spraying the same strength chemical into the air.  Air contains water (humidity), so the chemicals are diluted when air borne, meaning it is no longer the same concentration as in the aqueous form. Therefore, the amount of ‘contact time’ required is greater when fogging than if poured directly onto the organism.

ATi are one of the only specialist gas sensor companies in the world that makes an accurate H202 sensor that can be used to protect staff.  During the decontamination process, H2O2 is released into the air through fogging and needs to be monitored as part of Quality Controls Programmes.

Rooms, surfaces and equipment can be sterilised multiple times per day with higher levels of H2O2 than ever before, increasing the risk to those working close to them. Generating the right amount of gas is vital for efficacy over prolonged periods, it is therefore essential to understand and accurately monitor H2O2 levels.

Monitoring H2O2 levels enables the effective management of the breathing environment.  This continuous monitoring allows healthcare facilities to validate that the vapour levels in the air are safe.  The data from the monitoring can also be used to demonstrate and prove that staff and patients are not at risk when working in these potentially hazardous areas.

H202 Exposure Risks

The high reactivity of hydrogen peroxide that underlies its benefits also means that excessive exposure can be harmful and can cause serious health issues, including:

  • Burns to skin
  • Permanent damage to lungs
  • Pulmonary edema
  • Permanent damage to eyes/sight
  • Damage to ‘mucous membranes’

Protecting Lives Whilst Reducing Litigation Risks

The Health and Safety Executive (HSE) states that ‘The Control of Substances Hazardous to Health Regulations 2002 (COSHH) requires employers to prevent or control exposure to hazardous substances. Where exposure cannot be prevented, employers are required to assess the risk to health, and provide adequate control measures when using hazardous chemicals.’

With pressure mounting on the NHS to reduce ‘down time’ of beds for patients, companies that claim their decontamination procedure is the quickest with the best results are sometimes prioritised over alternatives that take longer. Competition to win tenders for contracts within the NHS is fierce, with decisions to award the decontamination provider of great value. This level of competitiveness can lead to many practical issues. One example of this is as recent as 2019, with reports that NHS staff  and patients were at risk of inhaling toxic fumes from cleaning machines following claims by a manufacturer of a fogging cleaning company that gas monitoring after a clean ‘was not needed’. The HSE investigated and found that the science and guidelines provided by the company failed to protect staff properly. As a result, Trusts using equipment that failed to monitor toxic gas levels were subjected to successful claims by staff and patients for compensation due to ill health and sickness.

Measuring the Efficacy of Decontamination and Safety

When decontaminating equipment, surfaces or the atmosphere, it is crucial to understand the process has been successful.  Log 6 reduction is the level that is used in the medical sector to denote a highly efficient sterilisation process. Achieving this sterilisation minimises the effect of any outbreak, whether it be Coronavirus, MRSA, Staphylococcus epididymitis, CBE infection, CRE infection, norovirus, or any other superbug.


Achieving the required sterility assurance level of log 6 requires the elimination of microorganism life. This means using strong agents that are harmful to the health of human beings should they touch or breathe it in.  It is vital for staff to know that the crucial H202 concentrations have been reached over the right period, in order to determine the efficacy of the decontamination process.  It is equally important to know when the high levels of H202 have dropped to a safe level to allow re-entry to the room.  One of the most reliable ways this can be proven is through the use of safe gas monitoring instrumentation that uses accurate and logged data. 

ATi’s PharmaSafe range offers both fixed and portable gas monitoring solutions that provide immediate decontamination validation throughout the sterilisation process. This gives instant peace of mind regarding the efficacy of the deep-clean, enabling staff to reduce downtime of the contaminated area.  The PharmaSafe range also allows for protection against over-gassing and can control unauthorised access to the rooms during decontamination. The versatile systems can also control dosing times and venting, post decontamination.

The systems use a specialist pre-calibrated H202 sensor and can also feature a built-in data logging facility for historical data capture, which can be used to prove or disprove claims of exposure. The system gives ‘peace of mind’ to the health & safety staff that all stakeholders are protected with alerts if limits are exceeded.

The application of ATi’s hydrogen peroxide sensors in decontamination equipment is a prime example of the way in which monitoring data provides crucial feedback to the efficacy of the clean, whilst helping to protect and save lives.  The PharmaSafe range can assist with the effectiveness of the decontamination process, providing an audit trail, whilst helping to keep key workers and members of the community safe.

ATi UK are a specialist sensor manufacturer and solutions provider with over 20 years’ experience. A trusted global supplier to the pharmaceutical and healthcare industry, our PharmaSafe range of innovative gas detection solutions are trusted the world over and come with award winning customer support. 


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