The Science of Hypochlorous Acid


By Tyler Williams, Director of Scientific Services, PathoSans

Today, cleaning is not just about appearance – it’s about cleaning for health. In commercial facilities, staff, customers and guests want assurance that cleaning programs effectively prevent the spread of infectious diseases without negatively impacting their wellbeing and the planet. To meet these new standards of clean, many facilities have transitioned to green cleaning programs using hypochlorous acid as an alternative to toxic disinfecting chemicals.

What is Hypochlorous Acid?

Hypochlorous acid (HOCl) is a unique chlorine subspecies well known for its antimicrobial properties. In fact, it’s most famously known for being naturally produced by white blood cells in all mammals to fight infections. The substance effectively eliminates a broad range of microorganisms. Recent technology in electrolysis has allowed this compound to be produced outside of our bodies. This process runs an electrical current through NaCl (table salt) and water and precisely controls the environment around the chemical (pH) to create a chemical reaction forming sodium hydroxide (NaOH) and hypochlorous acid (HOCl).

These two compounds are useful cleaning and disinfecting solutions for many types of hard and soft surfaces. Sodium hydroxide is a cleaner that removes soils, stains and residue build-up. Hypochlorous acid is a disinfectant that kills and inactivates a wide range of germs and viruses. Facilities can maximize the effectiveness of their cleaning programs by using the solutions in a two-step cleaning and disinfecting process.

Five Reasons to Use Hypochlorous Acid

Hypochlorous acid can transform cleaning programs for the better. Consider these five benefits for your facility:

  1. Efficacy. HOCl inactivates a variety of viruses, including coronaviruses, in less than one minute. In a comparison of disinfectants used in surgical centers, hypochlorous acid reduced the bacterial count significantly more than standard disinfectants. It’s also effective against the common cold, flu and norovirus, which is recognized as one of the most difficult viruses to kill.
  2. Safety. Producing HOCl using on-site generation (OSG) systems requires only water, salt and electricity, meaning the disinfectant has no added fragrances, preservatives or irritating odors. It has been proven to be non-irritating to eyes and skin and can be used without personal protective equipment (PPE) like gloves and masks.
  3. Sustainability. Unlike conventional chemicals that can pollute waterways, hypochlorous acid is safe to dispose of without environmental concerns. Plus, generating hypochlorous acid on site enables the use of reusable spray bottles, thereby reducing plastic waste. HOCl also does not contain volatile organic compounds (VOCs) that negatively impact indoor air quality.
  4. Availability. Since water, salt and electricity are easy to source and don’t rely on traditional chemical supply chains, facilities using OSG have an unlimited supply of cleaning and disinfecting solutions. This is especially important when supply chains experience delays or interruptions.
  5. Increased use. As we look beyond the pandemic, and the world begins to return to normal, there is one topic that seems to be sticking around: increased cleaning frequency. Janitorial services, once hidden in the back or performed during the nightshift, are now on display. As cleaning frequencies increase and tend to be on display, it is critical that chemicals used do not expose those around them to harmful residues or active ingredients. OSG chemistry is produced without irritating surfactants, fragrances or other builders that can cause harm.

How HOCl Compares to Traditional Chemicals

Now that we know how hypochlorous acid can benefit facilities, how does it compare to conventional disinfectants? These are the most important differences between three common types of disinfecting solutions and hypochlorous acid:

  • Quats. Quaternary ammonium compounds (Quats) are disinfecting chemicals commonly found in disinfecting wipes, sprays and other household cleaners. Often, commercial products that claim to be “antibacterial” contain quats. They can cause skin rashes, irritate lungs, contribute to asthma and exacerbate breathing problems. Recent studies have also found evidence that quats can impact fertility and cause birth defects in mice. Additionally, widespread use of quats is contributing to the prevalence of superbugs that are resistant to quats and antibiotics. Conversely, HOCI is powerful enough that target organisms can’t build a defense against HOCl, meaning that it will always be effective against pathogens.
  • Bleach. HOCI can be up to 80 times as effective as bleach, because its neutral charge allows it to easily infiltrate and attack pathogens in low concentrations. Bacteria and bleach both have a negative charge. As a result, bacteria can repel itself from bleach. To overcome the cell’s defenses, you need to apply more bleach, which creates additional risks. Bleach has a strong odor and can cause burns, while hypochlorous acid is non-irritating to eyes and skin. Inhalation of bleach over long periods could be carcinogenic. When mixed with the wrong chemicals, a high concentration of bleach can also cause lethal chemical reactions. For example, one restaurant worker died and ten others were sickened after accidentally mixing two cleaning products containing acid and bleach, producing noxious fumes.
  • Hydrogen peroxide. Hydrogen peroxide can inactivate and kill a wide range of viruses and bacteria. However, 3% hydrogen peroxide, the concentration typically sold in stores, can cause discoloration or break down marble or granite surfaces. Additionally, when applied along with vinegar or bleach, it can produce toxic chemicals that irritate eyes, skin and lungs. Concentrations higher than 3% can be dangerous, and those over 30% can cause chemical burns and explosions when mixed incorrectly. The potency of hydrogen peroxide reduces when exposed to light. Meanwhile, hypochlorous acid is compatible with many surfaces and won’t cause damage, and at its lower effective storage concentration greatly lowers safety risk.

The Solution that Cleans for Health

Hypochlorous acid can prevent the spread of infectious diseases as well if not better than conventional chemicals without the dangerous properties of bleach, quats and hydrogen peroxide. Choosing to use an OSG system to generate the disinfectant on site offers numerous benefits and demonstrates that your business cares for its staff, visitors and the environment.

Interested in learning more about how hypochlorous acid can benefit your cleaning program? Download our webinar recording on the topic here.

Tyler Williams is Director of Scientific Services at PathoSans, a leading provider of on-site generation (OSG) devices that produce ready-to-use, highly effective cleaners and sanitizers known as electrochemically activated (ECA) solutions. To learn more about effective cleaning and disinfecting solutions compatible with electrostatic technology, visit

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“ The PathoSans team is great: they set up and fine- tuned our system, and now we have a continuous supply of high-performance solutions. We do not need to order or pay for packaged chemicals, or worry about anything!”

“ We like the simplicity. It’s as easy as pushing a button, then opening a valve for the solution: a degreaser for our pots, pans, sinks and floors, and a sanitizer for our tables, cutting boards, utensils, anywhere we need to sanitize.”

“ We feel fantastic about the system because it’s completely green, saves us considerable money, and helps ensure employee and guest safety.”