Hydrogen Peroxide vs. Quats

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Written by:  Mark McInnesThe list of active ingredients available for disinfectants is lengthy and full of trade-offs, which involve finding the balance between the right amount of infection prevention properties while protecting the health of staff, building occupants, and the environment.Disinfectants are created with one purpose: to kill microbes and pathogens. In other words, by definition, disinfectants are destructive to cells, which means none are completely harmless. However, some active ingredients are safer for human health and the environment than others.

Common traditional active ingredients in disinfectants include alcohol, phenol, and chlorine. These chemicals can have risks associated with them ranging from flammability to long-lasting health effects, including occupational asthma. Understanding your active ingredients can help you make a more in-depth analysis of your choices.

For the purposes of this article, we will look at the active ingredients in hydrogen peroxide and some forms of quaternary ammonium compounds, which are generally considered to have less long-lasting health and environmental impacts. Understanding the basic science behind how disinfectants and their active ingredients work, and why some are safer, can help purchasers decide which disinfectants will work best for their facilities’ distinct needs.

Hydrogen Peroxide

Hydrogen Peroxide is often recognized as one of the safest types of disinfectants, both for human health and the environment. Most people are familiar with the hydrogen peroxide that is available in a brown bottle at the pharmacy. This is the 3% variety that can go on a wound or used as a mouthwash.

Hydrogen peroxide has a really nice environmental footprint. The breakdown components are water and oxygen. It has a very good health and safety profile, too. If you can use 3% to wash your mouth out at the dentist, you can be pretty confident that your health risk from exposure to it is limited.

Used as a disinfectant, hydrogen peroxide is active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores. Peroxides are oxidizing agents, which means they work by pulling electrons from other molecules in the cells.

Hydrogen peroxide literally attacks pathogens. This means the disinfectant that uses hydrogen peroxide as its main active ingredient can have an excellent kill claim; however, it can be unstable. If it comes into contact with other molecules like organics and soil that haven’t been cleaned before the disinfectant was sprayed, then effectiveness will degrade. Processes that include thorough cleaning before the disinfectant application will need to be a high priority when using hydrogen peroxide disinfectants.


Quaternary ammonium compounds, or quats, are generally considered to be somewhat less toxic than more traditional active ingredients like bleach and phenolics. However, when used at higher concentrations, quats can have health implications that include skin and respiratory irritation. For certain circumstances where stability and broad kill claims are critical, quats can be safer to use than other hospital-grade disinfectants with more traditional active ingredients.

Quats are generally fungicidal, bactericidal, and virucidal. Quats are generally understood to be catalytic, which means they aren’t destroyed in the process of killing the pathogens.

Quats get their name because there is a nitrogen in the middle of the molecule, and the nitrogen has four chains coming off of it. There are hundreds of different quats, and the labeling and discussion of them can become very detailed and specific. In addition, each quat has a different environmental profile. Some are more biodegradable than others, and the ones that are biodegradable will break down into different molecules, with different environmental footprints, all depending on the type of quat.

Like hydrogen peroxide, quats have a dental use, as they are often an active ingredient in toothpaste and mouthwash. They are considered safe enough to put in your mouth at low concentrations.

When it comes to the health risks associated with quats, it is often a matter of concentration. As the market demands quicker contact times and broader kill claims, some disinfectants will use higher concentrations of quats. Higher concentrations will come with increased health warnings.

In the last couple of years, you have seen quats used in disinfectants increase from a few hundred parts per million up to 3,000 parts per million and higher. Those concentrations begin to have health and environmental risks to them, although they do have shorter dwell times and broader kill claims.

Decision Outcomes

Any disinfecting solution you choose to bring into your infection prevention program will be an important aspect of a much larger program that must include planning, training, and fully understanding the processes needed to allow that disinfectant to prevent the spread of infection.

Mark McInnes

Mark McInnes holds a master’s degree in environmental and life sciences; he also has a certificate in infection prevention and control. McInnes frequently speaks across Canada and the United States on issues of infection prevention and the cleaning industry.