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HOCl vs. common disinfectants

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How hypochlorous acid stacks up against seven common disinfectant chemistries on spectrum, handling, materials, by-products, and logistics.

vs. Bleach vs. Quats vs. Alcohol vs. Hydrogen peroxide vs. Peracetic acid vs. Chlorine dioxide vs. Phenolics

Master comparison table

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	Spectrum						Use	Handling		Use	Handling	Materials		Environment	Supply
Disinfectant							Typical contact timeNot rated		PPE (per label / SDS)Not rated	Food-contact surfaces (regulatory basis)Not rated
Hypochlorous acid (HOCl)	In suspension tests: about 7-log in 5 min (Venkitanarayanan 1999); complete inactivation within 1 min at 20 ppm (Kim 2019).	In lab tests: 28–59 ppm in suspension within 10 s, and 125–250 ppm on carriers in 5–10 min (Hatanaka 2022); results on carriers, wipes and short sprays varied (Miyaoka 2021; Hamilton 2023).	In one lab study, 20–200 ppm for 10 min gave ≥3-log reductions of norovirus and surrogates on tile and steel (Park 2007); some enteroviruses resisted (Mokudai 2026).	In vitro, ~100 ppm gave ≥4-log in 60 s against yeasts and molds (Odorcic 2015); Aspergillus niger needed longer (Mokudai 2026).	40–120 mg/L for 1–6 min in lab tests (Zhang 2016); limited activity against some spore-formers (Mokudai 2026) and reduced efficacy in dirty conditions (Brown 2024).	Lab studies of specific formulations reduced bacterial biofilms (Palau 2022; Aherne 2022); Candida biofilms resisted (Harriott 2019).	In lab carrier tests, minutes: 10 min at 20–200 ppm on tile and steel (Park 2007); 5–10 min at 125–250 ppm (Hatanaka 2022). Seconds only in suspension tests. Soil and short sprays reduced the effect (Hamilton 2023).	Not established for surface-use solutions; we found no standard skin- or eye-irritation test of an HOCl surface solution. Results from specific lower-strength products don’t carry over to other solutions or to 200–500 ppm. An acidic HOCl product caused brief stinging or burning on broken skin in half of volunteers (Burian 2022), and in cell studies toxicity rose with concentration and contact time (Severing 2019; Reis 2021). Follow the label or SDS and avoid eye and skin contact.	Follow the product label or SDS. Wear eye protection and chemical-resistant gloves when handling concentrates or salt or acid additives, ventilate, and never mix with strong acids, ammonia or other cleaners.	40 CFR 180.940(a) exempts residues of hypochlorous acid and its sodium salt from a tolerance when used in an antimicrobial pesticide formulation on food-contact surfaces, at no more than 200 ppm total available chlorine, with adequate draining. Rinse and drain directions come from the registered product's label. (40 CFR 180.940(a))	Can smell of chlorine; no study has compared its odor with bleach or other disinfectants. HOCl evaporates from solution, more so when agitated, sprayed or misted, or at lower pH (Len 2002; Fukuzaki 2023), and airborne levels rose with solution strength in one misting test (Oikawa 2026). Never acidify below pH 4, which can release chlorine gas (NIOSH chlorine). Odor is not a measure of strength.	CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41). CDC’s Table 1 also notes that chlorine generated on-site by electrolyzing saline (>650–675 ppm active free chlorine) “will corrode metal instruments” (CDC 2008, p. 106–107). In one study (one knife per condition), steel boning knives repeatedly dipped in a 0.02% (about 200 ppm) HOCl product and rinsed showed the most rust, more than knives dipped in bleach at 7,500 or 30,000 ppm (Bryant 2026).	Made from salt and water (Rahman 2016). Surface residue not measured in our sources; follow the label’s rinse directions.	Loses strength over time, faster with heat and light (Reis 2021; Takeda 2021). CDC lists by-product hazards for hypochlorite (trihalomethane when hot water is hyperchlorinated; bis(chloromethyl) ether on contact with formaldehyde); HOCl is also free chlorine (CDC 2008, p. 41). Electrolyzed water used to treat irrigation water left chlorate in baby lettuce above the EU maximum residue limit for leafy greens (López-Gálvez 2018). For washing cabbage brined with bromide-rich salt, one study recommended bleach rather than slightly acidic electrolyzed water to limit brominated by-products (Kim 2023).	Yes, from salt, water and electricity. CDC: activity is “strongly affected by the concentration of the active ingredient (available free chlorine),” and pH, current and redox “must be closely monitored” (CDC 2008, p. 41).	Low input cost (salt, water, electricity), but CDC notes “the equipment required to produce the product can be expensive” because pH, current and redox must be closely monitored, and that superoxidized water “is intended to be generated fresh at the point of use” (CDC 2008, p. 41). Loses strength over days to weeks, faster with heat, light, open containers or pH ≤3; in one test, products at pH 5.0–6.4 kept their chlorine for the 21 days tested (Takeda 2021; Reis 2021; Len 2002). Store closed, cool and dark.
Sodium hypochlorite (bleach)	CDC: “broad spectrum of antimicrobial activity” (CDC 2008, p. 41)	Broad spectrum (CDC 2008, p. 41)	Broad spectrum; 25 viruses inactivated in 10 min at 200 ppm in one study CDC cites (CDC 2008, p. 42). In another lab study, bleach at 150–200 ppm inactivated a norovirus surrogate within 30 seconds even with fecal soil (Takimoto 2013).	Broad spectrum (CDC 2008, p. 41)	CDC: 100 ppm “will kill ≥99.9% of B. atrophaeus spores within 5 minutes”; acidified and regular bleach at 5,000 ppm can inactivate 10⁶ C. difficile spores in ≤10 min (CDC 2008, p. 42). Results depend on pH and surface: in one lab study, 5,000 ppm bleach diluted with water (pH about 11.9) gave less than a 1-log reduction of B. cereus spores in 10 min (Sil 2025), and in another, plain 0.5% bleach did not inactivate spores on cement or plywood after 1 hour (Oie 2011).	CDC: “remove dried or fixed organisms and biofilms from surfaces” (CDC 2008, p. 41)	Label-dependent.	At household-bleach concentration (5.25–6.15%), “can produce ocular irritation or oropharyngeal, esophageal, and gastric burns” (CDC 2008, p. 41); toxicity depends on concentration and pH (Slaughter 2019).	Follow the label or SDS. CDC links chlorine to occupational illness in cleaning staff and advises precautions “(e.g., gloves and proper ventilation)” (CDC 2008, p. 39); household-strength bleach can cause eye irritation (CDC 2008, p. 41).	Same 40 CFR 180.940(a) entry as HOCl (sodium salt of hypochlorous acid; ≤200 ppm total available chlorine; adequate draining). Follow the registered product's label. (40 CFR 180.940(a))	Chlorine (bleach) odor; diluted solutions are described as having a “faint chlorine-like odor” (PubChem: sodium hypochlorite). Releases chlorine gas if mixed with ammonia or acids (CDC 2008, p. 41).	CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41)	Surface residue not measured in our sources; follow the label’s rinse directions.	CDC: potential by-products include trihalomethane when hot water is hyperchlorinated and bis(chloromethyl) ether on contact with formaldehyde (CDC 2008, p. 41).	Most US chlorine products are 5.25–6.15% sodium hypochlorite solutions (household bleach) (CDC 2008, p. 40–41); on-site hypochlorite generation not assessed in our sources.	CDC: “inexpensive and fast acting.” Diluted (pH >8) solutions in closed opaque plastic can lose up to 40–50% of free available chlorine in 1 month; no decomposition after 30 days in a closed brown bottle (CDC 2008, p. 41). In one animal facility, 0.5% bleach in spray bottles held its free chlorine for 5–6 weeks; mean loss was 6–7% in bottles not sprayed daily (Gow 2022).
Quaternary ammonium (quats)	CDC: generally bactericidal (CDC 2008, p. 53)	CDC: “virucidal against lipophilic (enveloped) viruses” (CDC 2008, p. 53)	CDC: “generally not … virucidal against hydrophilic (nonenveloped) viruses” (CDC 2008, p. 53)	CDC: “generally fungicidal” (label-dependent) (CDC 2008, p. 53)	CDC: “not sporicidal” (CDC 2008, p. 53)	Not assessed in our sources.	Label-dependent.	Irritant at high concentrations or with prolonged use (Lauriola 2025)	Follow the label or SDS. CDC advises precautions such as “gloves and proper ventilation” when using disinfectants (CDC 2008, p. 39), and notes case reports of occupational asthma from benzalkonium chloride, a common quat (CDC 2008, p. 53).	Listed in 40 CFR 180.940 for use in antimicrobial formulations on food-contact surfaces, with end-use limits and adequate draining. Follow the registered product's label. (40 CFR 180.940(a))	Formulation-dependent; not assessed in our sources.	In one test CDC cites, computer keyboards showed no functional or cosmetic damage after 300 applications of a quat (the same held for alcohol, phenolic and 80 ppm chlorine wipes). Check the device maker’s compatibility guidance (CDC 2008, p. 53).	In a 2026 study of homes in South China, quats were detected in dust and hand wipes, and ingestion of surface residues was the main exposure route (Hu 2026). Ongoing (“residual”) antimicrobial activity applies only to products whose EPA-registered label claims it (EPA residual-efficacy guidance).	Not assessed in our sources.	Sold as formulated disinfectant products (CDC: “quaternaries sold as … disinfectants”) (CDC 2008, p. 53); not generated on-site.	Not assessed in our sources.
Alcohols (ethanol / isopropyl)	CDC: “rapidly bactericidal” (CDC 2008, p. 39)	CDC: ethanol 60–80% inactivates “all of the lipophilic viruses” (CDC 2008, p. 39)	Ethanol (60–80%) inactivates some non-enveloped viruses (adenovirus, enterovirus, rhinovirus, rotavirus) “but not hepatitis A virus (HAV) … or poliovirus”; isopropyl “is not active against the nonlipid enteroviruses” (CDC 2008, p. 40).	CDC: fungicidal (CDC 2008, p. 39)	CDC: “do not destroy bacterial spores” (CDC 2008, p. 39)	Not assessed in our sources.	“Rapidly bactericidal” (P. aeruginosa killed in 10 seconds by ethanol in a test CDC cites), but alcohols “evaporate rapidly, making extended exposure time difficult to achieve unless the items are immersed” (CDC 2008, p. 39–40).	Irritant with prolonged use or at high concentrations (Lauriola 2025)	CDC: “flammable and consequently must be stored in a cool, well-ventilated area” (CDC 2008, p. 40)	Ethanol is listed in 40 CFR 180.940 as a formulation ingredient. Follow the registered product's label. (40 CFR 180.940(a))	Not assessed in our sources.	CDC: “tend to swell and harden rubber and certain plastic tubing” with prolonged use, and “bleach rubber and plastic tiles” (CDC 2008, p. 40)	Evaporates rapidly (CDC 2008, p. 40); surface residue not assessed in our sources.	Evaporates rapidly into the air, and the vapors are flammable (CDC 2008, p. 40). Breakdown products not assessed in our sources.	Used as formulated solutions (ethanol is listed in 40 CFR 180.940 as a formulation ingredient) (40 CFR 180.940(a)); not generated on-site.	CDC: alcohols are “flammable and consequently must be stored in a cool, well-ventilated area” (CDC 2008, p. 40). Cost not assessed in our sources.
Hydrogen peroxide / accelerated HP	CDC: “active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores” (CDC 2008, p. 47)	CDC: “active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores” (CDC 2008, p. 47)	Strength-dependent: with 7.5%, “thirty minutes were required for >99.9% inactivation of poliovirus and HAV”; 3% and 6% did not inactivate HAV in 1 minute (CDC 2008, p. 48).	CDC: “active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores” (CDC 2008, p. 47)	At high strength and long contact: 7% stabilized hydrogen peroxide “proved to be sporicidal (6 hours of exposure)” (CDC 2008, p. 47).	Not assessed in our sources.	Label-dependent.	Irritant at high concentrations (Lauriola 2025)	Follow the label or SDS. At 7.5%, CDC lists hydrogen peroxide as a serious eye irritant (CDC 2008, p. 116), and NIOSH advises preventing skin and eye contact (NIOSH: hydrogen peroxide).	Listed in 40 CFR 180.940 for use in antimicrobial formulations on food-contact surfaces, with end-use limits and adequate draining. Follow the registered product's label. (40 CFR 180.940(a))	Little odor in use: CDC reports “no odor or irritation issues” for a 7.5% product (CDC 2008, p. 117). The pure compound has a “slightly sharp odor” (NIOSH: hydrogen peroxide).	CDC: at 7.5%, hydrogen peroxide “will corrode copper, zinc, and brass” (CDC 2008, p. 106–107), and it has caused cosmetic and functional changes on some devices (CDC 2008, p. 117).	Breaks down to water and oxygen (CDC 2008, p. 47); surface residue not assessed in our sources. Follow the label’s rinse directions.	Breaks down to water and oxygen (CDC 2008, p. 47); CDC lists no disposal restrictions for a 7.5% product (CDC 2008, p. 116).	Supplied as commercial solutions (CDC: “commercially available 3% hydrogen peroxide”; “a premixed, ready-to-use chemical” at 7.5%) (CDC 2008, p. 48); not generated on-site.	CDC: “extremely stable when properly stored (e.g., in dark containers)”; potency loss “less than 2% per year” (CDC 2008, p. 48). Concentrates are oxidizers.
Peracetic acid (PAA)	CDC: inactivates bacteria, fungi and yeasts in ≤5 minutes at <100 ppm (CDC 2008, p. 51)	CDC: “rapid action against all microorganisms” (CDC 2008, p. 51)	CDC: “the dosage range is wide (12–2250 ppm),” with poliovirus inactivated in yeast extract in 15 minutes with 1,500–2,250 ppm (CDC 2008, p. 51).	CDC: inactivates bacteria, fungi and yeasts in ≤5 minutes at <100 ppm (CDC 2008, p. 51)	CDC: “remains effective in the presence of organic matter and is sporicidal even at low temperatures” (CDC 2008, p. 51); held up under dirty conditions in one test (Brown 2024).	Not assessed in our sources.	Label-dependent.	CDC: a “serious eye and skin irritant” as a concentrated solution (CDC 2008, p. 116); irritant at high concentrations or with prolonged use (Lauriola 2025).	Follow the label or SDS. CDC warns of “serious eye and skin damage” from contact with concentrated solution, so protect eyes and skin when handling concentrate (CDC 2008, p. 117).	Listed in 40 CFR 180.940 for use in antimicrobial formulations on food-contact surfaces, with end-use limits and adequate draining. Follow the registered product's label. (40 CFR 180.940(a))	Strong, pungent, acrid odor as a concentrate (PubChem: peracetic acid). CDC rates odor “not significant” for one dilute peracetic acid–hydrogen peroxide product (CDC 2008, p. 117).	CDC: “can corrode copper, brass, bronze, plain steel, and galvanized iron,” though additives and pH changes reduce this (CDC 2008, p. 51)	CDC: “leaves no residue” (CDC 2008, p. 51)	CDC: “lacks harmful decomposition products (i.e., acetic acid, water, oxygen, hydrogen peroxide)” (CDC 2008, p. 51)	Supplied as formulated products, such as the peracetic acid–hydrogen peroxide formulations CDC describes (CDC 2008, p. 51); not generated on-site.	Hazardous concentrate (CDC 2008, p. 116); CDC: “unstable, particularly when diluted” (a 1% solution “loses half its strength through hydrolysis in 6 days”) (CDC 2008, p. 51).
Chlorine dioxide (ClO₂)	CDC: data support bactericidal, fungicidal … and virucidal label claims (CDC 2008, p. 42)	CDC: data support bactericidal, fungicidal … and virucidal label claims (CDC 2008, p. 42)	CDC: data “support manufacturers’ … virucidal label claims” (CDC 2008, p. 42); non-enveloped virus data not in our sources.	CDC: data support bactericidal, fungicidal … and virucidal label claims (CDC 2008, p. 42)	About 140 ppm gave a >10⁶ reduction of B. atrophaeus spores in 2.5 min with 3 g/L bovine albumin (suspension tests) (CDC 2008, p. 41); reduced efficacy in dirty conditions in one test (Brown 2024).	Not assessed in our sources.	Label-dependent.	The gas irritates the eyes, nose and throat, and exposure can cause cough, wheezing and bronchitis (NIOSH: chlorine dioxide).	Follow the label or SDS. NIOSH’s exposure limit is 0.1 ppm (8-hour average), and NIOSH lists respirators above that. Prevent skin and eye contact with the liquid (NIOSH: chlorine dioxide).	Oxychloro species (including chlorine dioxide) are listed in 40 CFR 180.940(b)–(c) for dairy and food-processing equipment, up to 200 ppm. Follow the registered product's label. (40 CFR 180.940(a))	Unpleasant odor similar to chlorine and nitric acid (NIOSH: chlorine dioxide).	A powerful oxidizer (NIOSH: chlorine dioxide). CDC notes long-term use “can damage the outer plastic coat” of endoscope insertion tubes, so check the device maker’s compatibility guidance (CDC 2008, p. 41).	Not assessed in our sources.	By-products depend on how it is generated; not assessed in our sources.	Prepared fresh “as required by mixing the two components” (CDC 2008, p. 41), or produced by mixing solutions (CDC 2008, p. 42); uses precursor chemicals, not salt and water.	Prepared fresh by mixing two components, a base solution and a sodium chlorite activator (CDC 2008, p. 41). Cost not assessed in our sources.
Phenolics	CDC: bactericidal, fungicidal, virucidal (CDC 2008, p. 52)	CDC: bactericidal, fungicidal, virucidal (CDC 2008, p. 52)	One study CDC cites “demonstrated little or no virucidal effect of a phenolic against coxsackie B4, echovirus 11, and poliovirus 1” (CDC 2008, p. 52).	CDC: bactericidal, fungicidal, virucidal (CDC 2008, p. 52)	CDC: “not sporicidal” (CDC 2008, p. 52)	Not assessed in our sources.	Label-dependent.	CDC: “absorbed by porous materials, and the residual disinfectant can irritate tissue”; skin depigmentation was reported in 1970 with certain phenolic germicidal detergents (CDC 2008, p. 52).	Follow the label or SDS. CDC notes residual phenolic “can irritate tissue” (CDC 2008, p. 52) and advises precautions such as “gloves and proper ventilation” with disinfectants (CDC 2008, p. 39).	Not assessed in our sources.	Phenolic odor that varies by product. Ortho-phenylphenol, a common phenolic active (CDC 2008, p. 52), is described as having a “mild characteristic” or “phenolic” odor (PubChem: 2-phenylphenol).	Not assessed in our sources.	Absorbed by porous materials, and the residual disinfectant “can irritate tissue” (CDC 2008, p. 52). CDC says surfaces such as infant bassinets should be “rinsed thoroughly with water” after phenolic cleaning (CDC 2008, p. 53).	Not assessed in our sources.	Supplied as EPA-registered germicide products (CDC: “many phenolic germicides are EPA-registered”) (CDC 2008, p. 52); not generated on-site.	Not assessed in our sources.

Hypochlorous acid (HOCl)Details

Bacteria: In suspension tests: about 7-log in 5 min (Venkitanarayanan 1999); complete inactivation within 1 min at 20 ppm (Kim 2019).
Enveloped viruses: In lab tests: 28–59 ppm in suspension within 10 s, and 125–250 ppm on carriers in 5–10 min (Hatanaka 2022); results on carriers, wipes and short sprays varied (Miyaoka 2021; Hamilton 2023).
Non-enveloped viruses: In one lab study, 20–200 ppm for 10 min gave ≥3-log reductions of norovirus and surrogates on tile and steel (Park 2007); some enteroviruses resisted (Mokudai 2026).
Fungi: In vitro, ~100 ppm gave ≥4-log in 60 s against yeasts and molds (Odorcic 2015); Aspergillus niger needed longer (Mokudai 2026).
Spores: 40–120 mg/L for 1–6 min in lab tests (Zhang 2016); limited activity against some spore-formers (Mokudai 2026) and reduced efficacy in dirty conditions (Brown 2024).
Biofilm: Lab studies of specific formulations reduced bacterial biofilms (Palau 2022; Aherne 2022); Candida biofilms resisted (Harriott 2019).
Typical contact time: In lab carrier tests, minutes: 10 min at 20–200 ppm on tile and steel (Park 2007); 5–10 min at 125–250 ppm (Hatanaka 2022). Seconds only in suspension tests. Soil and short sprays reduced the effect (Hamilton 2023).
Irritation hazard (per label / SDS): Not established for surface-use solutions; we found no standard skin- or eye-irritation test of an HOCl surface solution. Results from specific lower-strength products don’t carry over to other solutions or to 200–500 ppm. An acidic HOCl product caused brief stinging or burning on broken skin in half of volunteers (Burian 2022), and in cell studies toxicity rose with concentration and contact time (Severing 2019; Reis 2021). Follow the label or SDS and avoid eye and skin contact.
PPE (per label / SDS): Follow the product label or SDS. Wear eye protection and chemical-resistant gloves when handling concentrates or salt or acid additives, ventilate, and never mix with strong acids, ammonia or other cleaners.
Food-contact surfaces (regulatory basis): 40 CFR 180.940(a) exempts residues of hypochlorous acid and its sodium salt from a tolerance when used in an antimicrobial pesticide formulation on food-contact surfaces, at no more than 200 ppm total available chlorine, with adequate draining. Rinse and drain directions come from the registered product's label. (40 CFR 180.940(a))
Odor / fumes: Can smell of chlorine; no study has compared its odor with bleach or other disinfectants. HOCl evaporates from solution, more so when agitated, sprayed or misted, or at lower pH (Len 2002; Fukuzaki 2023), and airborne levels rose with solution strength in one misting test (Oikawa 2026). Never acidify below pH 4, which can release chlorine gas (NIOSH chlorine). Odor is not a measure of strength.
Corrosiveness: CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41). CDC’s Table 1 also notes that chlorine generated on-site by electrolyzing saline (>650–675 ppm active free chlorine) “will corrode metal instruments” (CDC 2008, p. 106–107). In one study (one knife per condition), steel boning knives repeatedly dipped in a 0.02% (about 200 ppm) HOCl product and rinsed showed the most rust, more than knives dipped in bleach at 7,500 or 30,000 ppm (Bryant 2026).
Residue: Made from salt and water (Rahman 2016). Surface residue not measured in our sources; follow the label’s rinse directions.
Breakdown products: Loses strength over time, faster with heat and light (Reis 2021; Takeda 2021). CDC lists by-product hazards for hypochlorite (trihalomethane when hot water is hyperchlorinated; bis(chloromethyl) ether on contact with formaldehyde); HOCl is also free chlorine (CDC 2008, p. 41). Electrolyzed water used to treat irrigation water left chlorate in baby lettuce above the EU maximum residue limit for leafy greens (López-Gálvez 2018). For washing cabbage brined with bromide-rich salt, one study recommended bleach rather than slightly acidic electrolyzed water to limit brominated by-products (Kim 2023).
On-site generation: Yes, from salt, water and electricity. CDC: activity is “strongly affected by the concentration of the active ingredient (available free chlorine),” and pH, current and redox “must be closely monitored” (CDC 2008, p. 41).
Cost & storage: Low input cost (salt, water, electricity), but CDC notes “the equipment required to produce the product can be expensive” because pH, current and redox must be closely monitored, and that superoxidized water “is intended to be generated fresh at the point of use” (CDC 2008, p. 41). Loses strength over days to weeks, faster with heat, light, open containers or pH ≤3; in one test, products at pH 5.0–6.4 kept their chlorine for the 21 days tested (Takeda 2021; Reis 2021; Len 2002). Store closed, cool and dark.

Sodium hypochlorite (bleach)Details

Bacteria: CDC: “broad spectrum of antimicrobial activity” (CDC 2008, p. 41)
Enveloped viruses: Broad spectrum (CDC 2008, p. 41)
Non-enveloped viruses: Broad spectrum; 25 viruses inactivated in 10 min at 200 ppm in one study CDC cites (CDC 2008, p. 42). In another lab study, bleach at 150–200 ppm inactivated a norovirus surrogate within 30 seconds even with fecal soil (Takimoto 2013).
Fungi: Broad spectrum (CDC 2008, p. 41)
Spores: CDC: 100 ppm “will kill ≥99.9% of B. atrophaeus spores within 5 minutes”; acidified and regular bleach at 5,000 ppm can inactivate 10⁶ C. difficile spores in ≤10 min (CDC 2008, p. 42). Results depend on pH and surface: in one lab study, 5,000 ppm bleach diluted with water (pH about 11.9) gave less than a 1-log reduction of B. cereus spores in 10 min (Sil 2025), and in another, plain 0.5% bleach did not inactivate spores on cement or plywood after 1 hour (Oie 2011).
Biofilm: CDC: “remove dried or fixed organisms and biofilms from surfaces” (CDC 2008, p. 41)
Typical contact time: Label-dependent.
Irritation hazard (per label / SDS): At household-bleach concentration (5.25–6.15%), “can produce ocular irritation or oropharyngeal, esophageal, and gastric burns” (CDC 2008, p. 41); toxicity depends on concentration and pH (Slaughter 2019).
PPE (per label / SDS): Follow the label or SDS. CDC links chlorine to occupational illness in cleaning staff and advises precautions “(e.g., gloves and proper ventilation)” (CDC 2008, p. 39); household-strength bleach can cause eye irritation (CDC 2008, p. 41).
Food-contact surfaces (regulatory basis): Same 40 CFR 180.940(a) entry as HOCl (sodium salt of hypochlorous acid; ≤200 ppm total available chlorine; adequate draining). Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes: Chlorine (bleach) odor; diluted solutions are described as having a “faint chlorine-like odor” (PubChem: sodium hypochlorite). Releases chlorine gas if mixed with ammonia or acids (CDC 2008, p. 41).
Corrosiveness: CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41)
Residue: Surface residue not measured in our sources; follow the label’s rinse directions.
Breakdown products: CDC: potential by-products include trihalomethane when hot water is hyperchlorinated and bis(chloromethyl) ether on contact with formaldehyde (CDC 2008, p. 41).
On-site generation: Most US chlorine products are 5.25–6.15% sodium hypochlorite solutions (household bleach) (CDC 2008, p. 40–41); on-site hypochlorite generation not assessed in our sources.
Cost & storage: CDC: “inexpensive and fast acting.” Diluted (pH >8) solutions in closed opaque plastic can lose up to 40–50% of free available chlorine in 1 month; no decomposition after 30 days in a closed brown bottle (CDC 2008, p. 41). In one animal facility, 0.5% bleach in spray bottles held its free chlorine for 5–6 weeks; mean loss was 6–7% in bottles not sprayed daily (Gow 2022).

Quaternary ammonium (quats)Details

Bacteria: CDC: generally bactericidal (CDC 2008, p. 53)
Enveloped viruses: CDC: “virucidal against lipophilic (enveloped) viruses” (CDC 2008, p. 53)
Non-enveloped viruses: CDC: “generally not … virucidal against hydrophilic (nonenveloped) viruses” (CDC 2008, p. 53)
Fungi: CDC: “generally fungicidal” (label-dependent) (CDC 2008, p. 53)
Spores: CDC: “not sporicidal” (CDC 2008, p. 53)
Biofilm: Not assessed in our sources.
Typical contact time: Label-dependent.
Irritation hazard (per label / SDS): Irritant at high concentrations or with prolonged use (Lauriola 2025)
PPE (per label / SDS): Follow the label or SDS. CDC advises precautions such as “gloves and proper ventilation” when using disinfectants (CDC 2008, p. 39), and notes case reports of occupational asthma from benzalkonium chloride, a common quat (CDC 2008, p. 53).
Food-contact surfaces (regulatory basis): Listed in 40 CFR 180.940 for use in antimicrobial formulations on food-contact surfaces, with end-use limits and adequate draining. Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes: Formulation-dependent; not assessed in our sources.
Corrosiveness: In one test CDC cites, computer keyboards showed no functional or cosmetic damage after 300 applications of a quat (the same held for alcohol, phenolic and 80 ppm chlorine wipes). Check the device maker’s compatibility guidance (CDC 2008, p. 53).
Residue: In a 2026 study of homes in South China, quats were detected in dust and hand wipes, and ingestion of surface residues was the main exposure route (Hu 2026). Ongoing (“residual”) antimicrobial activity applies only to products whose EPA-registered label claims it (EPA residual-efficacy guidance).
Breakdown products: Not assessed in our sources.
On-site generation: Sold as formulated disinfectant products (CDC: “quaternaries sold as … disinfectants”) (CDC 2008, p. 53); not generated on-site.
Cost & storage: Not assessed in our sources.

Alcohols (ethanol / isopropyl)Details

Bacteria: CDC: “rapidly bactericidal” (CDC 2008, p. 39)
Enveloped viruses: CDC: ethanol 60–80% inactivates “all of the lipophilic viruses” (CDC 2008, p. 39)
Non-enveloped viruses: Ethanol (60–80%) inactivates some non-enveloped viruses (adenovirus, enterovirus, rhinovirus, rotavirus) “but not hepatitis A virus (HAV) … or poliovirus”; isopropyl “is not active against the nonlipid enteroviruses” (CDC 2008, p. 40).
Fungi: CDC: fungicidal (CDC 2008, p. 39)
Spores: CDC: “do not destroy bacterial spores” (CDC 2008, p. 39)
Biofilm: Not assessed in our sources.
Typical contact time: “Rapidly bactericidal” (P. aeruginosa killed in 10 seconds by ethanol in a test CDC cites), but alcohols “evaporate rapidly, making extended exposure time difficult to achieve unless the items are immersed” (CDC 2008, p. 39–40).
Irritation hazard (per label / SDS): Irritant with prolonged use or at high concentrations (Lauriola 2025)
PPE (per label / SDS): CDC: “flammable and consequently must be stored in a cool, well-ventilated area” (CDC 2008, p. 40)
Food-contact surfaces (regulatory basis): Ethanol is listed in 40 CFR 180.940 as a formulation ingredient. Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes: Not assessed in our sources.
Corrosiveness: CDC: “tend to swell and harden rubber and certain plastic tubing” with prolonged use, and “bleach rubber and plastic tiles” (CDC 2008, p. 40)
Residue: Evaporates rapidly (CDC 2008, p. 40); surface residue not assessed in our sources.
Breakdown products: Evaporates rapidly into the air, and the vapors are flammable (CDC 2008, p. 40). Breakdown products not assessed in our sources.
On-site generation: Used as formulated solutions (ethanol is listed in 40 CFR 180.940 as a formulation ingredient) (40 CFR 180.940(a)); not generated on-site.
Cost & storage: CDC: alcohols are “flammable and consequently must be stored in a cool, well-ventilated area” (CDC 2008, p. 40). Cost not assessed in our sources.

Hydrogen peroxide / accelerated HPDetails

Bacteria: CDC: “active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores” (CDC 2008, p. 47)
Enveloped viruses: CDC: “active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores” (CDC 2008, p. 47)
Non-enveloped viruses: Strength-dependent: with 7.5%, “thirty minutes were required for >99.9% inactivation of poliovirus and HAV”; 3% and 6% did not inactivate HAV in 1 minute (CDC 2008, p. 48).
Fungi: CDC: “active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores” (CDC 2008, p. 47)
Spores: At high strength and long contact: 7% stabilized hydrogen peroxide “proved to be sporicidal (6 hours of exposure)” (CDC 2008, p. 47).
Biofilm: Not assessed in our sources.
Typical contact time: Label-dependent.
Irritation hazard (per label / SDS): Irritant at high concentrations (Lauriola 2025)
PPE (per label / SDS): Follow the label or SDS. At 7.5%, CDC lists hydrogen peroxide as a serious eye irritant (CDC 2008, p. 116), and NIOSH advises preventing skin and eye contact (NIOSH: hydrogen peroxide).
Food-contact surfaces (regulatory basis): Listed in 40 CFR 180.940 for use in antimicrobial formulations on food-contact surfaces, with end-use limits and adequate draining. Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes: Little odor in use: CDC reports “no odor or irritation issues” for a 7.5% product (CDC 2008, p. 117). The pure compound has a “slightly sharp odor” (NIOSH: hydrogen peroxide).
Corrosiveness: CDC: at 7.5%, hydrogen peroxide “will corrode copper, zinc, and brass” (CDC 2008, p. 106–107), and it has caused cosmetic and functional changes on some devices (CDC 2008, p. 117).
Residue: Breaks down to water and oxygen (CDC 2008, p. 47); surface residue not assessed in our sources. Follow the label’s rinse directions.
Breakdown products: Breaks down to water and oxygen (CDC 2008, p. 47); CDC lists no disposal restrictions for a 7.5% product (CDC 2008, p. 116).
On-site generation: Supplied as commercial solutions (CDC: “commercially available 3% hydrogen peroxide”; “a premixed, ready-to-use chemical” at 7.5%) (CDC 2008, p. 48); not generated on-site.
Cost & storage: CDC: “extremely stable when properly stored (e.g., in dark containers)”; potency loss “less than 2% per year” (CDC 2008, p. 48). Concentrates are oxidizers.

Peracetic acid (PAA)Details

Bacteria: CDC: inactivates bacteria, fungi and yeasts in ≤5 minutes at <100 ppm (CDC 2008, p. 51)
Enveloped viruses: CDC: “rapid action against all microorganisms” (CDC 2008, p. 51)
Non-enveloped viruses: CDC: “the dosage range is wide (12–2250 ppm),” with poliovirus inactivated in yeast extract in 15 minutes with 1,500–2,250 ppm (CDC 2008, p. 51).
Fungi: CDC: inactivates bacteria, fungi and yeasts in ≤5 minutes at <100 ppm (CDC 2008, p. 51)
Spores: CDC: “remains effective in the presence of organic matter and is sporicidal even at low temperatures” (CDC 2008, p. 51); held up under dirty conditions in one test (Brown 2024).
Biofilm: Not assessed in our sources.
Typical contact time: Label-dependent.
Irritation hazard (per label / SDS): CDC: a “serious eye and skin irritant” as a concentrated solution (CDC 2008, p. 116); irritant at high concentrations or with prolonged use (Lauriola 2025).
PPE (per label / SDS): Follow the label or SDS. CDC warns of “serious eye and skin damage” from contact with concentrated solution, so protect eyes and skin when handling concentrate (CDC 2008, p. 117).
Food-contact surfaces (regulatory basis): Listed in 40 CFR 180.940 for use in antimicrobial formulations on food-contact surfaces, with end-use limits and adequate draining. Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes: Strong, pungent, acrid odor as a concentrate (PubChem: peracetic acid). CDC rates odor “not significant” for one dilute peracetic acid–hydrogen peroxide product (CDC 2008, p. 117).
Corrosiveness: CDC: “can corrode copper, brass, bronze, plain steel, and galvanized iron,” though additives and pH changes reduce this (CDC 2008, p. 51)
Residue: CDC: “leaves no residue” (CDC 2008, p. 51)
Breakdown products: CDC: “lacks harmful decomposition products (i.e., acetic acid, water, oxygen, hydrogen peroxide)” (CDC 2008, p. 51)
On-site generation: Supplied as formulated products, such as the peracetic acid–hydrogen peroxide formulations CDC describes (CDC 2008, p. 51); not generated on-site.
Cost & storage: Hazardous concentrate (CDC 2008, p. 116); CDC: “unstable, particularly when diluted” (a 1% solution “loses half its strength through hydrolysis in 6 days”) (CDC 2008, p. 51).

Chlorine dioxide (ClO₂)Details

Bacteria: CDC: data support bactericidal, fungicidal … and virucidal label claims (CDC 2008, p. 42)
Enveloped viruses: CDC: data support bactericidal, fungicidal … and virucidal label claims (CDC 2008, p. 42)
Non-enveloped viruses: CDC: data “support manufacturers’ … virucidal label claims” (CDC 2008, p. 42); non-enveloped virus data not in our sources.
Fungi: CDC: data support bactericidal, fungicidal … and virucidal label claims (CDC 2008, p. 42)
Spores: About 140 ppm gave a >10⁶ reduction of B. atrophaeus spores in 2.5 min with 3 g/L bovine albumin (suspension tests) (CDC 2008, p. 41); reduced efficacy in dirty conditions in one test (Brown 2024).
Biofilm: Not assessed in our sources.
Typical contact time: Label-dependent.
Irritation hazard (per label / SDS): The gas irritates the eyes, nose and throat, and exposure can cause cough, wheezing and bronchitis (NIOSH: chlorine dioxide).
PPE (per label / SDS): Follow the label or SDS. NIOSH’s exposure limit is 0.1 ppm (8-hour average), and NIOSH lists respirators above that. Prevent skin and eye contact with the liquid (NIOSH: chlorine dioxide).
Food-contact surfaces (regulatory basis): Oxychloro species (including chlorine dioxide) are listed in 40 CFR 180.940(b)–(c) for dairy and food-processing equipment, up to 200 ppm. Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes: Unpleasant odor similar to chlorine and nitric acid (NIOSH: chlorine dioxide).
Corrosiveness: A powerful oxidizer (NIOSH: chlorine dioxide). CDC notes long-term use “can damage the outer plastic coat” of endoscope insertion tubes, so check the device maker’s compatibility guidance (CDC 2008, p. 41).
Residue: Not assessed in our sources.
Breakdown products: By-products depend on how it is generated; not assessed in our sources.
On-site generation: Prepared fresh “as required by mixing the two components” (CDC 2008, p. 41), or produced by mixing solutions (CDC 2008, p. 42); uses precursor chemicals, not salt and water.
Cost & storage: Prepared fresh by mixing two components, a base solution and a sodium chlorite activator (CDC 2008, p. 41). Cost not assessed in our sources.

PhenolicsDetails

Bacteria: CDC: bactericidal, fungicidal, virucidal (CDC 2008, p. 52)
Enveloped viruses: CDC: bactericidal, fungicidal, virucidal (CDC 2008, p. 52)
Non-enveloped viruses: One study CDC cites “demonstrated little or no virucidal effect of a phenolic against coxsackie B4, echovirus 11, and poliovirus 1” (CDC 2008, p. 52).
Fungi: CDC: bactericidal, fungicidal, virucidal (CDC 2008, p. 52)
Spores: CDC: “not sporicidal” (CDC 2008, p. 52)
Biofilm: Not assessed in our sources.
Typical contact time: Label-dependent.
Irritation hazard (per label / SDS): CDC: “absorbed by porous materials, and the residual disinfectant can irritate tissue”; skin depigmentation was reported in 1970 with certain phenolic germicidal detergents (CDC 2008, p. 52).
PPE (per label / SDS): Follow the label or SDS. CDC notes residual phenolic “can irritate tissue” (CDC 2008, p. 52) and advises precautions such as “gloves and proper ventilation” with disinfectants (CDC 2008, p. 39).
Food-contact surfaces (regulatory basis): Not assessed in our sources.
Odor / fumes: Phenolic odor that varies by product. Ortho-phenylphenol, a common phenolic active (CDC 2008, p. 52), is described as having a “mild characteristic” or “phenolic” odor (PubChem: 2-phenylphenol).
Corrosiveness: Not assessed in our sources.
Residue: Absorbed by porous materials, and the residual disinfectant “can irritate tissue” (CDC 2008, p. 52). CDC says surfaces such as infant bassinets should be “rinsed thoroughly with water” after phenolic cleaning (CDC 2008, p. 53).
Breakdown products: Not assessed in our sources.
On-site generation: Supplied as EPA-registered germicide products (CDC: “many phenolic germicides are EPA-registered”) (CDC 2008, p. 52); not generated on-site.
Cost & storage: Not assessed in our sources.

Contact times are set by each registered product’s label. PPE and food-contact directions also come only from a registered product’s label; those rows are not rated.

✓ Favorable◐ Mixed / depends✕ Less favorable— Not ratedEditorial ratings, qualitative only, based on the cited studies and guidance. “Not assessed” means our sources don’t cover it.

One-on-one

Head-to-head comparisons

Each matchup below is also a standalone page.

HOCl vs. Sodium hypochlorite (bleach)

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Bleach and HOCl are chemical cousins: both are forms of free chlorine. The difference is pH. Bleach is alkaline and mostly hypochlorite ion. At the same available chlorine, solutions near pH 5–6 contain much more hypochlorous acid (Wang 2007), and CDC notes that chlorine’s disinfecting efficacy falls as pH rises (CDC 2008, p. 41). Lab comparisons at equal, low chlorine levels showed this pH effect whether the lower-pH solution was electrolyzed water or bleach acidified under controlled conditions (Naka 2020; Quan 2010; Takimoto 2013; Yang 2021; Sil 2025); one study had an industry co-author (Naka 2020). At higher strengths, bleach did as well or better in one of these studies (Takimoto 2013), and CDC-cited bleach protocols use 100 to 5,000 ppm (CDC 2008, p. 42). These are lab findings, not product claims: use any disinfectant only as its label directs, and never mix bleach with any acid or acid-containing product, which can release chlorine gas (CDC 2008, p. 41). Bleach keeps its strength longer in storage than lower-pH chlorine solutions, and its alkaline form aids cleaning (Sil 2025; Len 2002; Fukuzaki 2006).

Key differences

Where HOCl rates higher

None in this table

Where bleach rates higher

Non-enveloped viruses
Spores
Biofilm
Cost & storage

Based on the qualitative ratings below; unrated rows are excluded.

Attribute	HOCl	Bleach
Bacteria	In suspension tests: about 7-log in 5 min (Venkitanarayanan 1999); complete inactivation within 1 min at 20 ppm (Kim 2019).	CDC: “broad spectrum of antimicrobial activity” (CDC 2008, p. 41)
Enveloped viruses	In lab tests: 28–59 ppm in suspension within 10 s, and 125–250 ppm on carriers in 5–10 min (Hatanaka 2022); results on carriers, wipes and short sprays varied (Miyaoka 2021; Hamilton 2023).	Broad spectrum (CDC 2008, p. 41)
Non-enveloped viruses	In one lab study, 20–200 ppm for 10 min gave ≥3-log reductions of norovirus and surrogates on tile and steel (Park 2007); some enteroviruses resisted (Mokudai 2026).	Broad spectrum; 25 viruses inactivated in 10 min at 200 ppm in one study CDC cites (CDC 2008, p. 42). In another lab study, bleach at 150–200 ppm inactivated a norovirus surrogate within 30 seconds even with fecal soil (Takimoto 2013).
Fungi	In vitro, ~100 ppm gave ≥4-log in 60 s against yeasts and molds (Odorcic 2015); Aspergillus niger needed longer (Mokudai 2026).	Broad spectrum (CDC 2008, p. 41)
Spores	40–120 mg/L for 1–6 min in lab tests (Zhang 2016); limited activity against some spore-formers (Mokudai 2026) and reduced efficacy in dirty conditions (Brown 2024).	CDC: 100 ppm “will kill ≥99.9% of B. atrophaeus spores within 5 minutes”; acidified and regular bleach at 5,000 ppm can inactivate 10⁶ C. difficile spores in ≤10 min (CDC 2008, p. 42). Results depend on pH and surface: in one lab study, 5,000 ppm bleach diluted with water (pH about 11.9) gave less than a 1-log reduction of B. cereus spores in 10 min (Sil 2025), and in another, plain 0.5% bleach did not inactivate spores on cement or plywood after 1 hour (Oie 2011).
Biofilm	Lab studies of specific formulations reduced bacterial biofilms (Palau 2022; Aherne 2022); Candida biofilms resisted (Harriott 2019).	CDC: “remove dried or fixed organisms and biofilms from surfaces” (CDC 2008, p. 41)
Typical contact time	In lab carrier tests, minutes: 10 min at 20–200 ppm on tile and steel (Park 2007); 5–10 min at 125–250 ppm (Hatanaka 2022). Seconds only in suspension tests. Soil and short sprays reduced the effect (Hamilton 2023).	Label-dependent.
Irritation hazard (per label / SDS)	Not established for surface-use solutions; we found no standard skin- or eye-irritation test of an HOCl surface solution. Results from specific lower-strength products don’t carry over to other solutions or to 200–500 ppm. An acidic HOCl product caused brief stinging or burning on broken skin in half of volunteers (Burian 2022), and in cell studies toxicity rose with concentration and contact time (Severing 2019; Reis 2021). Follow the label or SDS and avoid eye and skin contact.	At household-bleach concentration (5.25–6.15%), “can produce ocular irritation or oropharyngeal, esophageal, and gastric burns” (CDC 2008, p. 41); toxicity depends on concentration and pH (Slaughter 2019).
PPE (per label / SDS)	Follow the product label or SDS. Wear eye protection and chemical-resistant gloves when handling concentrates or salt or acid additives, ventilate, and never mix with strong acids, ammonia or other cleaners.	Follow the label or SDS. CDC links chlorine to occupational illness in cleaning staff and advises precautions “(e.g., gloves and proper ventilation)” (CDC 2008, p. 39); household-strength bleach can cause eye irritation (CDC 2008, p. 41).
Food-contact surfaces (regulatory basis)	40 CFR 180.940(a) exempts residues of hypochlorous acid and its sodium salt from a tolerance when used in an antimicrobial pesticide formulation on food-contact surfaces, at no more than 200 ppm total available chlorine, with adequate draining. Rinse and drain directions come from the registered product's label. (40 CFR 180.940(a))	Same 40 CFR 180.940(a) entry as HOCl (sodium salt of hypochlorous acid; ≤200 ppm total available chlorine; adequate draining). Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes	Can smell of chlorine; no study has compared its odor with bleach or other disinfectants. HOCl evaporates from solution, more so when agitated, sprayed or misted, or at lower pH (Len 2002; Fukuzaki 2023), and airborne levels rose with solution strength in one misting test (Oikawa 2026). Never acidify below pH 4, which can release chlorine gas (NIOSH chlorine). Odor is not a measure of strength.	Chlorine (bleach) odor; diluted solutions are described as having a “faint chlorine-like odor” (PubChem: sodium hypochlorite). Releases chlorine gas if mixed with ammonia or acids (CDC 2008, p. 41).
Corrosiveness	CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41). CDC’s Table 1 also notes that chlorine generated on-site by electrolyzing saline (>650–675 ppm active free chlorine) “will corrode metal instruments” (CDC 2008, p. 106–107). In one study (one knife per condition), steel boning knives repeatedly dipped in a 0.02% (about 200 ppm) HOCl product and rinsed showed the most rust, more than knives dipped in bleach at 7,500 or 30,000 ppm (Bryant 2026).	CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41)
Residue	Made from salt and water (Rahman 2016). Surface residue not measured in our sources; follow the label’s rinse directions.	Surface residue not measured in our sources; follow the label’s rinse directions.
Breakdown products	Loses strength over time, faster with heat and light (Reis 2021; Takeda 2021). CDC lists by-product hazards for hypochlorite (trihalomethane when hot water is hyperchlorinated; bis(chloromethyl) ether on contact with formaldehyde); HOCl is also free chlorine (CDC 2008, p. 41). Electrolyzed water used to treat irrigation water left chlorate in baby lettuce above the EU maximum residue limit for leafy greens (López-Gálvez 2018). For washing cabbage brined with bromide-rich salt, one study recommended bleach rather than slightly acidic electrolyzed water to limit brominated by-products (Kim 2023).	CDC: potential by-products include trihalomethane when hot water is hyperchlorinated and bis(chloromethyl) ether on contact with formaldehyde (CDC 2008, p. 41).
On-site generation	Yes, from salt, water and electricity. CDC: activity is “strongly affected by the concentration of the active ingredient (available free chlorine),” and pH, current and redox “must be closely monitored” (CDC 2008, p. 41).	Most US chlorine products are 5.25–6.15% sodium hypochlorite solutions (household bleach) (CDC 2008, p. 40–41); on-site hypochlorite generation not assessed in our sources.
Cost & storage	Low input cost (salt, water, electricity), but CDC notes “the equipment required to produce the product can be expensive” because pH, current and redox must be closely monitored, and that superoxidized water “is intended to be generated fresh at the point of use” (CDC 2008, p. 41). Loses strength over days to weeks, faster with heat, light, open containers or pH ≤3; in one test, products at pH 5.0–6.4 kept their chlorine for the 21 days tested (Takeda 2021; Reis 2021; Len 2002). Store closed, cool and dark.	CDC: “inexpensive and fast acting.” Diluted (pH >8) solutions in closed opaque plastic can lose up to 40–50% of free available chlorine in 1 month; no decomposition after 30 days in a closed brown bottle (CDC 2008, p. 41). In one animal facility, 0.5% bleach in spray bottles held its free chlorine for 5–6 weeks; mean loss was 6–7% in bottles not sprayed daily (Gow 2022).

Where bleach may be the better fit: Broad-spectrum disinfection where a cheap, widely available registered product is the priority (CDC: “unaffected by water hardness” (CDC 2008, p. 41)); spore protocols where CDC cites 5,000 ppm bleach (CDC 2008, p. 42); and jobs where a diluted solution needs to be stored for weeks: in one facility, 0.5% bleach in spray bottles held its strength for 5–6 weeks (Gow 2022), though CDC notes losses depend on the container (CDC 2008, p. 41).

HOCl vs. Quaternary ammonium (quats)

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Quats are widely used surface disinfectants, and CDC calls them “good cleaning agents.” They are “not sporicidal,” are generally not virucidal against non-enveloped viruses, and “high water hardness” can make them less microbicidal (CDC 2008, p. 53). Like most disinfectants, including hypochlorite, they can irritate or sensitize skin with heavy use (Lauriola 2025).

Key differences

Where HOCl rates higher

Non-enveloped viruses
Spores
On-site generation

Where quats rate higher

None in this table

Based on the qualitative ratings below; unrated rows are excluded.

Attribute	HOCl	Quats
Bacteria	In suspension tests: about 7-log in 5 min (Venkitanarayanan 1999); complete inactivation within 1 min at 20 ppm (Kim 2019).	CDC: generally bactericidal (CDC 2008, p. 53)
Enveloped viruses	In lab tests: 28–59 ppm in suspension within 10 s, and 125–250 ppm on carriers in 5–10 min (Hatanaka 2022); results on carriers, wipes and short sprays varied (Miyaoka 2021; Hamilton 2023).	CDC: “virucidal against lipophilic (enveloped) viruses” (CDC 2008, p. 53)
Non-enveloped viruses	In one lab study, 20–200 ppm for 10 min gave ≥3-log reductions of norovirus and surrogates on tile and steel (Park 2007); some enteroviruses resisted (Mokudai 2026).	CDC: “generally not … virucidal against hydrophilic (nonenveloped) viruses” (CDC 2008, p. 53)
Fungi	In vitro, ~100 ppm gave ≥4-log in 60 s against yeasts and molds (Odorcic 2015); Aspergillus niger needed longer (Mokudai 2026).	CDC: “generally fungicidal” (label-dependent) (CDC 2008, p. 53)
Spores	40–120 mg/L for 1–6 min in lab tests (Zhang 2016); limited activity against some spore-formers (Mokudai 2026) and reduced efficacy in dirty conditions (Brown 2024).	CDC: “not sporicidal” (CDC 2008, p. 53)
Biofilm	Lab studies of specific formulations reduced bacterial biofilms (Palau 2022; Aherne 2022); Candida biofilms resisted (Harriott 2019).	Not assessed in our sources.
Typical contact time	In lab carrier tests, minutes: 10 min at 20–200 ppm on tile and steel (Park 2007); 5–10 min at 125–250 ppm (Hatanaka 2022). Seconds only in suspension tests. Soil and short sprays reduced the effect (Hamilton 2023).	Label-dependent.
Irritation hazard (per label / SDS)	Not established for surface-use solutions; we found no standard skin- or eye-irritation test of an HOCl surface solution. Results from specific lower-strength products don’t carry over to other solutions or to 200–500 ppm. An acidic HOCl product caused brief stinging or burning on broken skin in half of volunteers (Burian 2022), and in cell studies toxicity rose with concentration and contact time (Severing 2019; Reis 2021). Follow the label or SDS and avoid eye and skin contact.	Irritant at high concentrations or with prolonged use (Lauriola 2025)
PPE (per label / SDS)	Follow the product label or SDS. Wear eye protection and chemical-resistant gloves when handling concentrates or salt or acid additives, ventilate, and never mix with strong acids, ammonia or other cleaners.	Follow the label or SDS. CDC advises precautions such as “gloves and proper ventilation” when using disinfectants (CDC 2008, p. 39), and notes case reports of occupational asthma from benzalkonium chloride, a common quat (CDC 2008, p. 53).
Food-contact surfaces (regulatory basis)	40 CFR 180.940(a) exempts residues of hypochlorous acid and its sodium salt from a tolerance when used in an antimicrobial pesticide formulation on food-contact surfaces, at no more than 200 ppm total available chlorine, with adequate draining. Rinse and drain directions come from the registered product's label. (40 CFR 180.940(a))	Listed in 40 CFR 180.940 for use in antimicrobial formulations on food-contact surfaces, with end-use limits and adequate draining. Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes	Can smell of chlorine; no study has compared its odor with bleach or other disinfectants. HOCl evaporates from solution, more so when agitated, sprayed or misted, or at lower pH (Len 2002; Fukuzaki 2023), and airborne levels rose with solution strength in one misting test (Oikawa 2026). Never acidify below pH 4, which can release chlorine gas (NIOSH chlorine). Odor is not a measure of strength.	Formulation-dependent; not assessed in our sources.
Corrosiveness	CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41). CDC’s Table 1 also notes that chlorine generated on-site by electrolyzing saline (>650–675 ppm active free chlorine) “will corrode metal instruments” (CDC 2008, p. 106–107). In one study (one knife per condition), steel boning knives repeatedly dipped in a 0.02% (about 200 ppm) HOCl product and rinsed showed the most rust, more than knives dipped in bleach at 7,500 or 30,000 ppm (Bryant 2026).	In one test CDC cites, computer keyboards showed no functional or cosmetic damage after 300 applications of a quat (the same held for alcohol, phenolic and 80 ppm chlorine wipes). Check the device maker’s compatibility guidance (CDC 2008, p. 53).
Residue	Made from salt and water (Rahman 2016). Surface residue not measured in our sources; follow the label’s rinse directions.	In a 2026 study of homes in South China, quats were detected in dust and hand wipes, and ingestion of surface residues was the main exposure route (Hu 2026). Ongoing (“residual”) antimicrobial activity applies only to products whose EPA-registered label claims it (EPA residual-efficacy guidance).
Breakdown products	Loses strength over time, faster with heat and light (Reis 2021; Takeda 2021). CDC lists by-product hazards for hypochlorite (trihalomethane when hot water is hyperchlorinated; bis(chloromethyl) ether on contact with formaldehyde); HOCl is also free chlorine (CDC 2008, p. 41). Electrolyzed water used to treat irrigation water left chlorate in baby lettuce above the EU maximum residue limit for leafy greens (López-Gálvez 2018). For washing cabbage brined with bromide-rich salt, one study recommended bleach rather than slightly acidic electrolyzed water to limit brominated by-products (Kim 2023).	Not assessed in our sources.
On-site generation	Yes, from salt, water and electricity. CDC: activity is “strongly affected by the concentration of the active ingredient (available free chlorine),” and pH, current and redox “must be closely monitored” (CDC 2008, p. 41).	Sold as formulated disinfectant products (CDC: “quaternaries sold as … disinfectants”) (CDC 2008, p. 53); not generated on-site.
Cost & storage	Low input cost (salt, water, electricity), but CDC notes “the equipment required to produce the product can be expensive” because pH, current and redox must be closely monitored, and that superoxidized water “is intended to be generated fresh at the point of use” (CDC 2008, p. 41). Loses strength over days to weeks, faster with heat, light, open containers or pH ≤3; in one test, products at pH 5.0–6.4 kept their chlorine for the 21 days tested (Takeda 2021; Reis 2021; Len 2002). Store closed, cool and dark.	Not assessed in our sources.

Where quats may be the better fit: Uses that call for a registered product with a residual-efficacy label claim (EPA residual-efficacy guidance), and where non-enveloped viruses and spores are not the main concern.

HOCl vs. Alcohols (ethanol / isopropyl)

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Alcohols are “rapidly bactericidal,” but they “evaporate rapidly,” are flammable, and “do not destroy bacterial spores” (CDC 2008, p. 39–40).

Key differences

Where HOCl rates higher

Spores
On-site generation

Where alcohol rates higher

None in this table

Based on the qualitative ratings below; unrated rows are excluded.

Attribute	HOCl	Alcohol
Bacteria	In suspension tests: about 7-log in 5 min (Venkitanarayanan 1999); complete inactivation within 1 min at 20 ppm (Kim 2019).	CDC: “rapidly bactericidal” (CDC 2008, p. 39)
Enveloped viruses	In lab tests: 28–59 ppm in suspension within 10 s, and 125–250 ppm on carriers in 5–10 min (Hatanaka 2022); results on carriers, wipes and short sprays varied (Miyaoka 2021; Hamilton 2023).	CDC: ethanol 60–80% inactivates “all of the lipophilic viruses” (CDC 2008, p. 39)
Non-enveloped viruses	In one lab study, 20–200 ppm for 10 min gave ≥3-log reductions of norovirus and surrogates on tile and steel (Park 2007); some enteroviruses resisted (Mokudai 2026).	Ethanol (60–80%) inactivates some non-enveloped viruses (adenovirus, enterovirus, rhinovirus, rotavirus) “but not hepatitis A virus (HAV) … or poliovirus”; isopropyl “is not active against the nonlipid enteroviruses” (CDC 2008, p. 40).
Fungi	In vitro, ~100 ppm gave ≥4-log in 60 s against yeasts and molds (Odorcic 2015); Aspergillus niger needed longer (Mokudai 2026).	CDC: fungicidal (CDC 2008, p. 39)
Spores	40–120 mg/L for 1–6 min in lab tests (Zhang 2016); limited activity against some spore-formers (Mokudai 2026) and reduced efficacy in dirty conditions (Brown 2024).	CDC: “do not destroy bacterial spores” (CDC 2008, p. 39)
Biofilm	Lab studies of specific formulations reduced bacterial biofilms (Palau 2022; Aherne 2022); Candida biofilms resisted (Harriott 2019).	Not assessed in our sources.
Typical contact time	In lab carrier tests, minutes: 10 min at 20–200 ppm on tile and steel (Park 2007); 5–10 min at 125–250 ppm (Hatanaka 2022). Seconds only in suspension tests. Soil and short sprays reduced the effect (Hamilton 2023).	“Rapidly bactericidal” (P. aeruginosa killed in 10 seconds by ethanol in a test CDC cites), but alcohols “evaporate rapidly, making extended exposure time difficult to achieve unless the items are immersed” (CDC 2008, p. 39–40).
Irritation hazard (per label / SDS)	Not established for surface-use solutions; we found no standard skin- or eye-irritation test of an HOCl surface solution. Results from specific lower-strength products don’t carry over to other solutions or to 200–500 ppm. An acidic HOCl product caused brief stinging or burning on broken skin in half of volunteers (Burian 2022), and in cell studies toxicity rose with concentration and contact time (Severing 2019; Reis 2021). Follow the label or SDS and avoid eye and skin contact.	Irritant with prolonged use or at high concentrations (Lauriola 2025)
PPE (per label / SDS)	Follow the product label or SDS. Wear eye protection and chemical-resistant gloves when handling concentrates or salt or acid additives, ventilate, and never mix with strong acids, ammonia or other cleaners.	CDC: “flammable and consequently must be stored in a cool, well-ventilated area” (CDC 2008, p. 40)
Food-contact surfaces (regulatory basis)	40 CFR 180.940(a) exempts residues of hypochlorous acid and its sodium salt from a tolerance when used in an antimicrobial pesticide formulation on food-contact surfaces, at no more than 200 ppm total available chlorine, with adequate draining. Rinse and drain directions come from the registered product's label. (40 CFR 180.940(a))	Ethanol is listed in 40 CFR 180.940 as a formulation ingredient. Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes	Can smell of chlorine; no study has compared its odor with bleach or other disinfectants. HOCl evaporates from solution, more so when agitated, sprayed or misted, or at lower pH (Len 2002; Fukuzaki 2023), and airborne levels rose with solution strength in one misting test (Oikawa 2026). Never acidify below pH 4, which can release chlorine gas (NIOSH chlorine). Odor is not a measure of strength.	Not assessed in our sources.
Corrosiveness	CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41). CDC’s Table 1 also notes that chlorine generated on-site by electrolyzing saline (>650–675 ppm active free chlorine) “will corrode metal instruments” (CDC 2008, p. 106–107). In one study (one knife per condition), steel boning knives repeatedly dipped in a 0.02% (about 200 ppm) HOCl product and rinsed showed the most rust, more than knives dipped in bleach at 7,500 or 30,000 ppm (Bryant 2026).	CDC: “tend to swell and harden rubber and certain plastic tubing” with prolonged use, and “bleach rubber and plastic tiles” (CDC 2008, p. 40)
Residue	Made from salt and water (Rahman 2016). Surface residue not measured in our sources; follow the label’s rinse directions.	Evaporates rapidly (CDC 2008, p. 40); surface residue not assessed in our sources.
Breakdown products	Loses strength over time, faster with heat and light (Reis 2021; Takeda 2021). CDC lists by-product hazards for hypochlorite (trihalomethane when hot water is hyperchlorinated; bis(chloromethyl) ether on contact with formaldehyde); HOCl is also free chlorine (CDC 2008, p. 41). Electrolyzed water used to treat irrigation water left chlorate in baby lettuce above the EU maximum residue limit for leafy greens (López-Gálvez 2018). For washing cabbage brined with bromide-rich salt, one study recommended bleach rather than slightly acidic electrolyzed water to limit brominated by-products (Kim 2023).	Evaporates rapidly into the air, and the vapors are flammable (CDC 2008, p. 40). Breakdown products not assessed in our sources.
On-site generation	Yes, from salt, water and electricity. CDC: activity is “strongly affected by the concentration of the active ingredient (available free chlorine),” and pH, current and redox “must be closely monitored” (CDC 2008, p. 41).	Used as formulated solutions (ethanol is listed in 40 CFR 180.940 as a formulation ingredient) (40 CFR 180.940(a)); not generated on-site.
Cost & storage	Low input cost (salt, water, electricity), but CDC notes “the equipment required to produce the product can be expensive” because pH, current and redox must be closely monitored, and that superoxidized water “is intended to be generated fresh at the point of use” (CDC 2008, p. 41). Loses strength over days to weeks, faster with heat, light, open containers or pH ≤3; in one test, products at pH 5.0–6.4 kept their chlorine for the 21 days tested (Takeda 2021; Reis 2021; Len 2002). Store closed, cool and dark.	CDC: alcohols are “flammable and consequently must be stored in a cool, well-ventilated area” (CDC 2008, p. 40). Cost not assessed in our sources.

Where alcohol may be the better fit: Quick-drying use on small items and electronics, where fast kill of vegetative bacteria and rapid evaporation are the priority (CDC 2008, p. 39–40).

HOCl vs. Hydrogen peroxide / accelerated HP

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Hydrogen peroxide, especially accelerated hydrogen peroxide (AHP), is a common surface disinfectant. Like HOCl it breaks down to simple products, and CDC calls it “extremely stable when properly stored” (CDC 2008, p. 48). In an unoccupied test-chamber study, dry fogs of both inactivated two respiratory viruses, depending on concentration and time (Urushidani 2022). EPA does not recommend fogging or misting unless a product’s label allows it (EPA fogging FAQ).

Key differences

Where HOCl rates higher

On-site generation

Where hydrogen peroxide rates higher

Breakdown products

Based on the qualitative ratings below; unrated rows are excluded.

Attribute	HOCl	Hydrogen peroxide
Bacteria	In suspension tests: about 7-log in 5 min (Venkitanarayanan 1999); complete inactivation within 1 min at 20 ppm (Kim 2019).	CDC: “active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores” (CDC 2008, p. 47)
Enveloped viruses	In lab tests: 28–59 ppm in suspension within 10 s, and 125–250 ppm on carriers in 5–10 min (Hatanaka 2022); results on carriers, wipes and short sprays varied (Miyaoka 2021; Hamilton 2023).	CDC: “active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores” (CDC 2008, p. 47)
Non-enveloped viruses	In one lab study, 20–200 ppm for 10 min gave ≥3-log reductions of norovirus and surrogates on tile and steel (Park 2007); some enteroviruses resisted (Mokudai 2026).	Strength-dependent: with 7.5%, “thirty minutes were required for >99.9% inactivation of poliovirus and HAV”; 3% and 6% did not inactivate HAV in 1 minute (CDC 2008, p. 48).
Fungi	In vitro, ~100 ppm gave ≥4-log in 60 s against yeasts and molds (Odorcic 2015); Aspergillus niger needed longer (Mokudai 2026).	CDC: “active against a wide range of microorganisms, including bacteria, yeasts, fungi, viruses, and spores” (CDC 2008, p. 47)
Spores	40–120 mg/L for 1–6 min in lab tests (Zhang 2016); limited activity against some spore-formers (Mokudai 2026) and reduced efficacy in dirty conditions (Brown 2024).	At high strength and long contact: 7% stabilized hydrogen peroxide “proved to be sporicidal (6 hours of exposure)” (CDC 2008, p. 47).
Biofilm	Lab studies of specific formulations reduced bacterial biofilms (Palau 2022; Aherne 2022); Candida biofilms resisted (Harriott 2019).	Not assessed in our sources.
Typical contact time	In lab carrier tests, minutes: 10 min at 20–200 ppm on tile and steel (Park 2007); 5–10 min at 125–250 ppm (Hatanaka 2022). Seconds only in suspension tests. Soil and short sprays reduced the effect (Hamilton 2023).	Label-dependent.
Irritation hazard (per label / SDS)	Not established for surface-use solutions; we found no standard skin- or eye-irritation test of an HOCl surface solution. Results from specific lower-strength products don’t carry over to other solutions or to 200–500 ppm. An acidic HOCl product caused brief stinging or burning on broken skin in half of volunteers (Burian 2022), and in cell studies toxicity rose with concentration and contact time (Severing 2019; Reis 2021). Follow the label or SDS and avoid eye and skin contact.	Irritant at high concentrations (Lauriola 2025)
PPE (per label / SDS)	Follow the product label or SDS. Wear eye protection and chemical-resistant gloves when handling concentrates or salt or acid additives, ventilate, and never mix with strong acids, ammonia or other cleaners.	Follow the label or SDS. At 7.5%, CDC lists hydrogen peroxide as a serious eye irritant (CDC 2008, p. 116), and NIOSH advises preventing skin and eye contact (NIOSH: hydrogen peroxide).
Food-contact surfaces (regulatory basis)	40 CFR 180.940(a) exempts residues of hypochlorous acid and its sodium salt from a tolerance when used in an antimicrobial pesticide formulation on food-contact surfaces, at no more than 200 ppm total available chlorine, with adequate draining. Rinse and drain directions come from the registered product's label. (40 CFR 180.940(a))	Listed in 40 CFR 180.940 for use in antimicrobial formulations on food-contact surfaces, with end-use limits and adequate draining. Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes	Can smell of chlorine; no study has compared its odor with bleach or other disinfectants. HOCl evaporates from solution, more so when agitated, sprayed or misted, or at lower pH (Len 2002; Fukuzaki 2023), and airborne levels rose with solution strength in one misting test (Oikawa 2026). Never acidify below pH 4, which can release chlorine gas (NIOSH chlorine). Odor is not a measure of strength.	Little odor in use: CDC reports “no odor or irritation issues” for a 7.5% product (CDC 2008, p. 117). The pure compound has a “slightly sharp odor” (NIOSH: hydrogen peroxide).
Corrosiveness	CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41). CDC’s Table 1 also notes that chlorine generated on-site by electrolyzing saline (>650–675 ppm active free chlorine) “will corrode metal instruments” (CDC 2008, p. 106–107). In one study (one knife per condition), steel boning knives repeatedly dipped in a 0.02% (about 200 ppm) HOCl product and rinsed showed the most rust, more than knives dipped in bleach at 7,500 or 30,000 ppm (Bryant 2026).	CDC: at 7.5%, hydrogen peroxide “will corrode copper, zinc, and brass” (CDC 2008, p. 106–107), and it has caused cosmetic and functional changes on some devices (CDC 2008, p. 117).
Residue	Made from salt and water (Rahman 2016). Surface residue not measured in our sources; follow the label’s rinse directions.	Breaks down to water and oxygen (CDC 2008, p. 47); surface residue not assessed in our sources. Follow the label’s rinse directions.
Breakdown products	Loses strength over time, faster with heat and light (Reis 2021; Takeda 2021). CDC lists by-product hazards for hypochlorite (trihalomethane when hot water is hyperchlorinated; bis(chloromethyl) ether on contact with formaldehyde); HOCl is also free chlorine (CDC 2008, p. 41). Electrolyzed water used to treat irrigation water left chlorate in baby lettuce above the EU maximum residue limit for leafy greens (López-Gálvez 2018). For washing cabbage brined with bromide-rich salt, one study recommended bleach rather than slightly acidic electrolyzed water to limit brominated by-products (Kim 2023).	Breaks down to water and oxygen (CDC 2008, p. 47); CDC lists no disposal restrictions for a 7.5% product (CDC 2008, p. 116).
On-site generation	Yes, from salt, water and electricity. CDC: activity is “strongly affected by the concentration of the active ingredient (available free chlorine),” and pH, current and redox “must be closely monitored” (CDC 2008, p. 41).	Supplied as commercial solutions (CDC: “commercially available 3% hydrogen peroxide”; “a premixed, ready-to-use chemical” at 7.5%) (CDC 2008, p. 48); not generated on-site.
Cost & storage	Low input cost (salt, water, electricity), but CDC notes “the equipment required to produce the product can be expensive” because pH, current and redox must be closely monitored, and that superoxidized water “is intended to be generated fresh at the point of use” (CDC 2008, p. 41). Loses strength over days to weeks, faster with heat, light, open containers or pH ≤3; in one test, products at pH 5.0–6.4 kept their chlorine for the 21 days tested (Takeda 2021; Reis 2021; Len 2002). Store closed, cool and dark.	CDC: “extremely stable when properly stored (e.g., in dark containers)”; potency loss “less than 2% per year” (CDC 2008, p. 48). Concentrates are oxidizers.

Where hydrogen peroxide may be the better fit: Settings that want a long shelf life, low odor and breakdown to water and oxygen, or that rely on accelerated hydrogen peroxide products (CDC: a 0.5% AHP “demonstrated bactericidal and virucidal activity in 1 minute and mycobactericidal and fungicidal activity in 5 minutes”) (CDC 2008, p. 47); and some sporicidal uses at higher strengths.

HOCl vs. Peracetic acid (PAA)

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Peracetic acid is a powerful oxidizer used widely in food processing. CDC notes it “remains effective in the presence of organic matter” and “leaves no residue” (CDC 2008, p. 51), and in one sporicidal test it held up better than chlorine products under dirty conditions (Brown 2024). Its strength comes with a pungent concentrate odor (PubChem: peracetic acid), irritation, and hazardous-concentrate handling (CDC 2008, p. 116–117).

Key differences

Where HOCl rates higher

On-site generation
Cost & storage

Where peracetic acid rates higher

Spores
Breakdown products

Based on the qualitative ratings below; unrated rows are excluded.

Attribute	HOCl	Peracetic acid
Bacteria	In suspension tests: about 7-log in 5 min (Venkitanarayanan 1999); complete inactivation within 1 min at 20 ppm (Kim 2019).	CDC: inactivates bacteria, fungi and yeasts in ≤5 minutes at <100 ppm (CDC 2008, p. 51)
Enveloped viruses	In lab tests: 28–59 ppm in suspension within 10 s, and 125–250 ppm on carriers in 5–10 min (Hatanaka 2022); results on carriers, wipes and short sprays varied (Miyaoka 2021; Hamilton 2023).	CDC: “rapid action against all microorganisms” (CDC 2008, p. 51)
Non-enveloped viruses	In one lab study, 20–200 ppm for 10 min gave ≥3-log reductions of norovirus and surrogates on tile and steel (Park 2007); some enteroviruses resisted (Mokudai 2026).	CDC: “the dosage range is wide (12–2250 ppm),” with poliovirus inactivated in yeast extract in 15 minutes with 1,500–2,250 ppm (CDC 2008, p. 51).
Fungi	In vitro, ~100 ppm gave ≥4-log in 60 s against yeasts and molds (Odorcic 2015); Aspergillus niger needed longer (Mokudai 2026).	CDC: inactivates bacteria, fungi and yeasts in ≤5 minutes at <100 ppm (CDC 2008, p. 51)
Spores	40–120 mg/L for 1–6 min in lab tests (Zhang 2016); limited activity against some spore-formers (Mokudai 2026) and reduced efficacy in dirty conditions (Brown 2024).	CDC: “remains effective in the presence of organic matter and is sporicidal even at low temperatures” (CDC 2008, p. 51); held up under dirty conditions in one test (Brown 2024).
Biofilm	Lab studies of specific formulations reduced bacterial biofilms (Palau 2022; Aherne 2022); Candida biofilms resisted (Harriott 2019).	Not assessed in our sources.
Typical contact time	In lab carrier tests, minutes: 10 min at 20–200 ppm on tile and steel (Park 2007); 5–10 min at 125–250 ppm (Hatanaka 2022). Seconds only in suspension tests. Soil and short sprays reduced the effect (Hamilton 2023).	Label-dependent.
Irritation hazard (per label / SDS)	Not established for surface-use solutions; we found no standard skin- or eye-irritation test of an HOCl surface solution. Results from specific lower-strength products don’t carry over to other solutions or to 200–500 ppm. An acidic HOCl product caused brief stinging or burning on broken skin in half of volunteers (Burian 2022), and in cell studies toxicity rose with concentration and contact time (Severing 2019; Reis 2021). Follow the label or SDS and avoid eye and skin contact.	CDC: a “serious eye and skin irritant” as a concentrated solution (CDC 2008, p. 116); irritant at high concentrations or with prolonged use (Lauriola 2025).
PPE (per label / SDS)	Follow the product label or SDS. Wear eye protection and chemical-resistant gloves when handling concentrates or salt or acid additives, ventilate, and never mix with strong acids, ammonia or other cleaners.	Follow the label or SDS. CDC warns of “serious eye and skin damage” from contact with concentrated solution, so protect eyes and skin when handling concentrate (CDC 2008, p. 117).
Food-contact surfaces (regulatory basis)	40 CFR 180.940(a) exempts residues of hypochlorous acid and its sodium salt from a tolerance when used in an antimicrobial pesticide formulation on food-contact surfaces, at no more than 200 ppm total available chlorine, with adequate draining. Rinse and drain directions come from the registered product's label. (40 CFR 180.940(a))	Listed in 40 CFR 180.940 for use in antimicrobial formulations on food-contact surfaces, with end-use limits and adequate draining. Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes	Can smell of chlorine; no study has compared its odor with bleach or other disinfectants. HOCl evaporates from solution, more so when agitated, sprayed or misted, or at lower pH (Len 2002; Fukuzaki 2023), and airborne levels rose with solution strength in one misting test (Oikawa 2026). Never acidify below pH 4, which can release chlorine gas (NIOSH chlorine). Odor is not a measure of strength.	Strong, pungent, acrid odor as a concentrate (PubChem: peracetic acid). CDC rates odor “not significant” for one dilute peracetic acid–hydrogen peroxide product (CDC 2008, p. 117).
Corrosiveness	CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41). CDC’s Table 1 also notes that chlorine generated on-site by electrolyzing saline (>650–675 ppm active free chlorine) “will corrode metal instruments” (CDC 2008, p. 106–107). In one study (one knife per condition), steel boning knives repeatedly dipped in a 0.02% (about 200 ppm) HOCl product and rinsed showed the most rust, more than knives dipped in bleach at 7,500 or 30,000 ppm (Bryant 2026).	CDC: “can corrode copper, brass, bronze, plain steel, and galvanized iron,” though additives and pH changes reduce this (CDC 2008, p. 51)
Residue	Made from salt and water (Rahman 2016). Surface residue not measured in our sources; follow the label’s rinse directions.	CDC: “leaves no residue” (CDC 2008, p. 51)
Breakdown products	Loses strength over time, faster with heat and light (Reis 2021; Takeda 2021). CDC lists by-product hazards for hypochlorite (trihalomethane when hot water is hyperchlorinated; bis(chloromethyl) ether on contact with formaldehyde); HOCl is also free chlorine (CDC 2008, p. 41). Electrolyzed water used to treat irrigation water left chlorate in baby lettuce above the EU maximum residue limit for leafy greens (López-Gálvez 2018). For washing cabbage brined with bromide-rich salt, one study recommended bleach rather than slightly acidic electrolyzed water to limit brominated by-products (Kim 2023).	CDC: “lacks harmful decomposition products (i.e., acetic acid, water, oxygen, hydrogen peroxide)” (CDC 2008, p. 51)
On-site generation	Yes, from salt, water and electricity. CDC: activity is “strongly affected by the concentration of the active ingredient (available free chlorine),” and pH, current and redox “must be closely monitored” (CDC 2008, p. 41).	Supplied as formulated products, such as the peracetic acid–hydrogen peroxide formulations CDC describes (CDC 2008, p. 51); not generated on-site.
Cost & storage	Low input cost (salt, water, electricity), but CDC notes “the equipment required to produce the product can be expensive” because pH, current and redox must be closely monitored, and that superoxidized water “is intended to be generated fresh at the point of use” (CDC 2008, p. 41). Loses strength over days to weeks, faster with heat, light, open containers or pH ≤3; in one test, products at pH 5.0–6.4 kept their chlorine for the 21 days tested (Takeda 2021; Reis 2021; Len 2002). Store closed, cool and dark.	Hazardous concentrate (CDC 2008, p. 116); CDC: “unstable, particularly when diluted” (a 1% solution “loses half its strength through hydrolysis in 6 days”) (CDC 2008, p. 51).

Where peracetic acid may be the better fit: Industrial food processing and sterilant applications where its sporicidal strength and performance in organic matter (CDC: 200–500 ppm required with organic matter) justify stricter PPE and handling (CDC 2008, p. 51).

HOCl vs. Chlorine dioxide (ClO₂)

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Chlorine dioxide is a strong oxidizing gas, typically generated on-site from precursor chemicals. HOCl can also be made on-site, but from salt, water, and electricity. In one lab study of irrigation water (one author works for an electrolyzed-water company), electrolyzed water at 20 mg/L free chlorine reduced foodborne bacteria more than chlorine dioxide or sodium hypochlorite under high organic load; at 5 mg/L the three performed comparably (Ogunniyi 2019).

Key differences

Where HOCl rates higher

On-site generation

Where chlorine dioxide rates higher

Spores

Based on the qualitative ratings below; unrated rows are excluded.

Attribute	HOCl	Chlorine dioxide
Bacteria	In suspension tests: about 7-log in 5 min (Venkitanarayanan 1999); complete inactivation within 1 min at 20 ppm (Kim 2019).	CDC: data support bactericidal, fungicidal … and virucidal label claims (CDC 2008, p. 42)
Enveloped viruses	In lab tests: 28–59 ppm in suspension within 10 s, and 125–250 ppm on carriers in 5–10 min (Hatanaka 2022); results on carriers, wipes and short sprays varied (Miyaoka 2021; Hamilton 2023).	CDC: data support bactericidal, fungicidal … and virucidal label claims (CDC 2008, p. 42)
Non-enveloped viruses	In one lab study, 20–200 ppm for 10 min gave ≥3-log reductions of norovirus and surrogates on tile and steel (Park 2007); some enteroviruses resisted (Mokudai 2026).	CDC: data “support manufacturers’ … virucidal label claims” (CDC 2008, p. 42); non-enveloped virus data not in our sources.
Fungi	In vitro, ~100 ppm gave ≥4-log in 60 s against yeasts and molds (Odorcic 2015); Aspergillus niger needed longer (Mokudai 2026).	CDC: data support bactericidal, fungicidal … and virucidal label claims (CDC 2008, p. 42)
Spores	40–120 mg/L for 1–6 min in lab tests (Zhang 2016); limited activity against some spore-formers (Mokudai 2026) and reduced efficacy in dirty conditions (Brown 2024).	About 140 ppm gave a >10⁶ reduction of B. atrophaeus spores in 2.5 min with 3 g/L bovine albumin (suspension tests) (CDC 2008, p. 41); reduced efficacy in dirty conditions in one test (Brown 2024).
Biofilm	Lab studies of specific formulations reduced bacterial biofilms (Palau 2022; Aherne 2022); Candida biofilms resisted (Harriott 2019).	Not assessed in our sources.
Typical contact time	In lab carrier tests, minutes: 10 min at 20–200 ppm on tile and steel (Park 2007); 5–10 min at 125–250 ppm (Hatanaka 2022). Seconds only in suspension tests. Soil and short sprays reduced the effect (Hamilton 2023).	Label-dependent.
Irritation hazard (per label / SDS)	Not established for surface-use solutions; we found no standard skin- or eye-irritation test of an HOCl surface solution. Results from specific lower-strength products don’t carry over to other solutions or to 200–500 ppm. An acidic HOCl product caused brief stinging or burning on broken skin in half of volunteers (Burian 2022), and in cell studies toxicity rose with concentration and contact time (Severing 2019; Reis 2021). Follow the label or SDS and avoid eye and skin contact.	The gas irritates the eyes, nose and throat, and exposure can cause cough, wheezing and bronchitis (NIOSH: chlorine dioxide).
PPE (per label / SDS)	Follow the product label or SDS. Wear eye protection and chemical-resistant gloves when handling concentrates or salt or acid additives, ventilate, and never mix with strong acids, ammonia or other cleaners.	Follow the label or SDS. NIOSH’s exposure limit is 0.1 ppm (8-hour average), and NIOSH lists respirators above that. Prevent skin and eye contact with the liquid (NIOSH: chlorine dioxide).
Food-contact surfaces (regulatory basis)	40 CFR 180.940(a) exempts residues of hypochlorous acid and its sodium salt from a tolerance when used in an antimicrobial pesticide formulation on food-contact surfaces, at no more than 200 ppm total available chlorine, with adequate draining. Rinse and drain directions come from the registered product's label. (40 CFR 180.940(a))	Oxychloro species (including chlorine dioxide) are listed in 40 CFR 180.940(b)–(c) for dairy and food-processing equipment, up to 200 ppm. Follow the registered product's label. (40 CFR 180.940(a))
Odor / fumes	Can smell of chlorine; no study has compared its odor with bleach or other disinfectants. HOCl evaporates from solution, more so when agitated, sprayed or misted, or at lower pH (Len 2002; Fukuzaki 2023), and airborne levels rose with solution strength in one misting test (Oikawa 2026). Never acidify below pH 4, which can release chlorine gas (NIOSH chlorine). Odor is not a measure of strength.	Unpleasant odor similar to chlorine and nitric acid (NIOSH: chlorine dioxide).
Corrosiveness	CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41). CDC’s Table 1 also notes that chlorine generated on-site by electrolyzing saline (>650–675 ppm active free chlorine) “will corrode metal instruments” (CDC 2008, p. 106–107). In one study (one knife per condition), steel boning knives repeatedly dipped in a 0.02% (about 200 ppm) HOCl product and rinsed showed the most rust, more than knives dipped in bleach at 7,500 or 30,000 ppm (Bryant 2026).	A powerful oxidizer (NIOSH: chlorine dioxide). CDC notes long-term use “can damage the outer plastic coat” of endoscope insertion tubes, so check the device maker’s compatibility guidance (CDC 2008, p. 41).
Residue	Made from salt and water (Rahman 2016). Surface residue not measured in our sources; follow the label’s rinse directions.	Not assessed in our sources.
Breakdown products	Loses strength over time, faster with heat and light (Reis 2021; Takeda 2021). CDC lists by-product hazards for hypochlorite (trihalomethane when hot water is hyperchlorinated; bis(chloromethyl) ether on contact with formaldehyde); HOCl is also free chlorine (CDC 2008, p. 41). Electrolyzed water used to treat irrigation water left chlorate in baby lettuce above the EU maximum residue limit for leafy greens (López-Gálvez 2018). For washing cabbage brined with bromide-rich salt, one study recommended bleach rather than slightly acidic electrolyzed water to limit brominated by-products (Kim 2023).	By-products depend on how it is generated; not assessed in our sources.
On-site generation	Yes, from salt, water and electricity. CDC: activity is “strongly affected by the concentration of the active ingredient (available free chlorine),” and pH, current and redox “must be closely monitored” (CDC 2008, p. 41).	Prepared fresh “as required by mixing the two components” (CDC 2008, p. 41), or produced by mixing solutions (CDC 2008, p. 42); uses precursor chemicals, not salt and water.
Cost & storage	Low input cost (salt, water, electricity), but CDC notes “the equipment required to produce the product can be expensive” because pH, current and redox must be closely monitored, and that superoxidized water “is intended to be generated fresh at the point of use” (CDC 2008, p. 41). Loses strength over days to weeks, faster with heat, light, open containers or pH ≤3; in one test, products at pH 5.0–6.4 kept their chlorine for the 21 days tested (Takeda 2021; Reis 2021; Len 2002). Store closed, cool and dark.	Prepared fresh by mixing two components, a base solution and a sodium chlorite activator (CDC 2008, p. 41). Cost not assessed in our sources.

Where chlorine dioxide may be the better fit: Water treatment and fumigation-type applications that need a gas-phase oxidizer, under trained handling.

HOCl vs. Phenolics

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Phenolics are older disinfectants that leave a residual and are still specified in some laboratory protocols. They are not sporicidal. Residues absorbed by porous materials can irritate tissue, and CDC notes “the use of phenolics in nurseries has been questioned because of hyperbilirubinemia in infants placed in bassinets where phenolic detergents were used” (CDC 2008, p. 53).

Key differences

Where HOCl rates higher

Non-enveloped viruses
Spores
On-site generation

Where phenolics rate higher

None in this table

Based on the qualitative ratings below; unrated rows are excluded.

Attribute	HOCl	Phenolics
Bacteria	In suspension tests: about 7-log in 5 min (Venkitanarayanan 1999); complete inactivation within 1 min at 20 ppm (Kim 2019).	CDC: bactericidal, fungicidal, virucidal (CDC 2008, p. 52)
Enveloped viruses	In lab tests: 28–59 ppm in suspension within 10 s, and 125–250 ppm on carriers in 5–10 min (Hatanaka 2022); results on carriers, wipes and short sprays varied (Miyaoka 2021; Hamilton 2023).	CDC: bactericidal, fungicidal, virucidal (CDC 2008, p. 52)
Non-enveloped viruses	In one lab study, 20–200 ppm for 10 min gave ≥3-log reductions of norovirus and surrogates on tile and steel (Park 2007); some enteroviruses resisted (Mokudai 2026).	One study CDC cites “demonstrated little or no virucidal effect of a phenolic against coxsackie B4, echovirus 11, and poliovirus 1” (CDC 2008, p. 52).
Fungi	In vitro, ~100 ppm gave ≥4-log in 60 s against yeasts and molds (Odorcic 2015); Aspergillus niger needed longer (Mokudai 2026).	CDC: bactericidal, fungicidal, virucidal (CDC 2008, p. 52)
Spores	40–120 mg/L for 1–6 min in lab tests (Zhang 2016); limited activity against some spore-formers (Mokudai 2026) and reduced efficacy in dirty conditions (Brown 2024).	CDC: “not sporicidal” (CDC 2008, p. 52)
Biofilm	Lab studies of specific formulations reduced bacterial biofilms (Palau 2022; Aherne 2022); Candida biofilms resisted (Harriott 2019).	Not assessed in our sources.
Typical contact time	In lab carrier tests, minutes: 10 min at 20–200 ppm on tile and steel (Park 2007); 5–10 min at 125–250 ppm (Hatanaka 2022). Seconds only in suspension tests. Soil and short sprays reduced the effect (Hamilton 2023).	Label-dependent.
Irritation hazard (per label / SDS)	Not established for surface-use solutions; we found no standard skin- or eye-irritation test of an HOCl surface solution. Results from specific lower-strength products don’t carry over to other solutions or to 200–500 ppm. An acidic HOCl product caused brief stinging or burning on broken skin in half of volunteers (Burian 2022), and in cell studies toxicity rose with concentration and contact time (Severing 2019; Reis 2021). Follow the label or SDS and avoid eye and skin contact.	CDC: “absorbed by porous materials, and the residual disinfectant can irritate tissue”; skin depigmentation was reported in 1970 with certain phenolic germicidal detergents (CDC 2008, p. 52).
PPE (per label / SDS)	Follow the product label or SDS. Wear eye protection and chemical-resistant gloves when handling concentrates or salt or acid additives, ventilate, and never mix with strong acids, ammonia or other cleaners.	Follow the label or SDS. CDC notes residual phenolic “can irritate tissue” (CDC 2008, p. 52) and advises precautions such as “gloves and proper ventilation” with disinfectants (CDC 2008, p. 39).
Food-contact surfaces (regulatory basis)	40 CFR 180.940(a) exempts residues of hypochlorous acid and its sodium salt from a tolerance when used in an antimicrobial pesticide formulation on food-contact surfaces, at no more than 200 ppm total available chlorine, with adequate draining. Rinse and drain directions come from the registered product's label. (40 CFR 180.940(a))	Not assessed in our sources.
Odor / fumes	Can smell of chlorine; no study has compared its odor with bleach or other disinfectants. HOCl evaporates from solution, more so when agitated, sprayed or misted, or at lower pH (Len 2002; Fukuzaki 2023), and airborne levels rose with solution strength in one misting test (Oikawa 2026). Never acidify below pH 4, which can release chlorine gas (NIOSH chlorine). Odor is not a measure of strength.	Phenolic odor that varies by product. Ortho-phenylphenol, a common phenolic active (CDC 2008, p. 52), is described as having a “mild characteristic” or “phenolic” odor (PubChem: 2-phenylphenol).
Corrosiveness	CDC: corrosive “to metals in high concentrations (>500 ppm)”; check with the device manufacturer for compatibility (CDC 2008, p. 41). CDC’s Table 1 also notes that chlorine generated on-site by electrolyzing saline (>650–675 ppm active free chlorine) “will corrode metal instruments” (CDC 2008, p. 106–107). In one study (one knife per condition), steel boning knives repeatedly dipped in a 0.02% (about 200 ppm) HOCl product and rinsed showed the most rust, more than knives dipped in bleach at 7,500 or 30,000 ppm (Bryant 2026).	Not assessed in our sources.
Residue	Made from salt and water (Rahman 2016). Surface residue not measured in our sources; follow the label’s rinse directions.	Absorbed by porous materials, and the residual disinfectant “can irritate tissue” (CDC 2008, p. 52). CDC says surfaces such as infant bassinets should be “rinsed thoroughly with water” after phenolic cleaning (CDC 2008, p. 53).
Breakdown products	Loses strength over time, faster with heat and light (Reis 2021; Takeda 2021). CDC lists by-product hazards for hypochlorite (trihalomethane when hot water is hyperchlorinated; bis(chloromethyl) ether on contact with formaldehyde); HOCl is also free chlorine (CDC 2008, p. 41). Electrolyzed water used to treat irrigation water left chlorate in baby lettuce above the EU maximum residue limit for leafy greens (López-Gálvez 2018). For washing cabbage brined with bromide-rich salt, one study recommended bleach rather than slightly acidic electrolyzed water to limit brominated by-products (Kim 2023).	Not assessed in our sources.
On-site generation	Yes, from salt, water and electricity. CDC: activity is “strongly affected by the concentration of the active ingredient (available free chlorine),” and pH, current and redox “must be closely monitored” (CDC 2008, p. 41).	Supplied as EPA-registered germicide products (CDC: “many phenolic germicides are EPA-registered”) (CDC 2008, p. 52); not generated on-site.
Cost & storage	Low input cost (salt, water, electricity), but CDC notes “the equipment required to produce the product can be expensive” because pH, current and redox must be closely monitored, and that superoxidized water “is intended to be generated fresh at the point of use” (CDC 2008, p. 41). Loses strength over days to weeks, faster with heat, light, open containers or pH ≤3; in one test, products at pH 5.0–6.4 kept their chlorine for the 21 days tested (Takeda 2021; Reis 2021; Len 2002). Store closed, cool and dark.	Not assessed in our sources.

Where phenolics may be the better fit: Laboratory and facility surface protocols that specify a registered phenolic; CDC notes many phenolics are EPA-registered for environmental surfaces such as laboratory surfaces (CDC 2008, p. 52).

How we rate

Each cell compares typical in-use solutions, not concentrates, and summarizes what the cited lab studies, CDC guidance, EPA regulations and chemical-hazard references report. Ratings are qualitative editorial judgments, not test scores, and they are not a measure of any product’s performance.

Four states. ✓ favorable, ◐ mixed or depends on conditions, ✕ less favorable, and — not rated.
Sources on every rating. Every rated cell links to at least one source. If our sources don’t cover an attribute, the cell says “Not assessed in our sources” and is left unrated.
Label rows are never rated. Contact time, PPE and food-contact use are set by each registered product’s label, so those rows describe the regulatory or label basis only.
One standard for every chemistry. HOCl is held to the same sourcing rules as the other chemistries. Where the same source applies to two chemistries (for example, CDC’s free-chlorine guidance for HOCl and bleach), we quote it the same way for both.
Key differences are generated, not written. The “Key differences” lists on each matchup are built automatically from the ratings. Unrated rows are excluded.
Evidence type and funding are shown. The Sources list tags each study with its evidence type (for example, suspension test, carrier test, review or guidance) and notes industry funding or author affiliations.
Who rates. Ratings are researched and written by the disinfectant.org Editorial Team. disinfectant.org is funded and produced by HOCL LLC, which sells equipment that makes HOCl (who funds this site). Spotted an error? See corrections.

Sources

Wang L, Bassiri M, Najafi R, et al. Hypochlorous acid as a potential wound care agent: Part I. J Burns Wounds. 2007;6:e5. pubmed.ncbi.nlm.nih.gov/17492050/. PMID 17492050. (authors from the product developer) review
Rutala WA, Weber DJ, Healthcare Infection Control Practices Advisory Committee (HICPAC). Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008 (last update June 2024). CDC. www.cdc.gov/infection-control/media/pdfs/Guideline-Disinfection-H.pdf. guidance
Naka A, Yakubo M, Nakamura K, Kurahashi M. Effectiveness of slightly acidic electrolyzed water on bacteria reduction: in vitro and spray evaluation. PeerJ. 2020;8:e8593. doi.org/10.7717/peerj.8593. PMID 32110494. (co-author employed by Toyotomi Co.; electrolyzed-water generator maker thanked for technical help) in vitro (suspension) + spray
Quan Y, Choi KD, Chung D, Shin IS. Evaluation of bactericidal activity of weakly acidic electrolyzed water (WAEW) against Vibrio vulnificus and Vibrio parahaemolyticus. Int J Food Microbiol. 2010;136(3):255-260. doi.org/10.1016/j.ijfoodmicro.2009.11.005. PMID 20004034. in vitro (suspension)
Takimoto K, Taharaguchi M, Sakai K, et al. Effect of hypochlorite-based disinfectants on inactivation of murine norovirus… Exp Anim. 2013;62(3):237-245. doi.org/10.1538/expanim.62.237. PMID 23903059. (acidified solution made with a commercial device; no maker authors) in vitro (suspension)
Yang G, Shi Y, Zhao Z, et al. Comparison of inactivation effect of slightly acidic electrolyzed water and sodium hypochlorite on Bacillus cereus spores. Foodborne Pathog Dis. 2021;18(3):192-201. doi.org/10.1089/fpd.2020.2811. PMID 33121277. (one author affiliation is a food company) in vitro (suspension)
Sil TB, Malyshev D, Aspholm M, Andersson M. Boosting hypochlorite's disinfection power through pH modulation. BMC Microbiol. 2025;25:101. doi.org/10.1186/s12866-025-03831-w. PMID 40021972. in vitro
Len SV, Hung YC, Chung D, Anderson JL, Erickson MC, Morita K. Effects of storage conditions and pH on chlorine loss in electrolyzed oxidizing (EO) water. J Agric Food Chem. 2002;50(1):209-212. doi.org/10.1021/jf010822v. PMID 11754569. lab (storage chemistry)
Fukuzaki S. Mechanisms of actions of sodium hypochlorite in cleaning and disinfection processes. Biocontrol Sci. 2006;11(4):147-157. doi.org/10.4265/bio.11.147. PMID 17190269. review
Gow CK, Weinhouse C, Johnson GO, Saunders KE. Stability of free available chlorine levels in dilute sodium hypochlorite solutions over a 6-week period. J Am Assoc Lab Anim Sci. 2022;61(2):181-187. doi.org/10.30802/AALAS-JAALAS-21-000080. PMID 35109965. stability (one facility)
Venkitanarayanan KS, Ezeike GO, Hung YC, Doyle MP. Efficacy of electrolyzed oxidizing water for inactivating Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes. Appl Environ Microbiol. 1999;65(9):4276-4279. doi.org/10.1128/AEM.65.9.4276-4279.1999. PMID 10473453. in vitro (suspension)
Kim HJ, Tango CN, Chelliah R, Oh DH. Sanitization efficacy of slightly acidic electrolyzed water against pure cultures of E. coli, Salmonella Typhimurium, S. aureus and B. cereus spores, in comparison with different water hardness. Sci Rep. 2019;9:4348. doi.org/10.1038/s41598-019-40846-6. PMID 30867518. in vitro (suspension)
Hatanaka N, Yasugi M, Sato T, Mukamoto M, Yamasaki S. Hypochlorous acid solution is a potent antiviral agent against SARS-CoV-2. J Appl Microbiol. 2022;132(2):1496-1502. doi.org/10.1111/jam.15284. PMID 34480823. (industry-funded) suspension + carrier
Miyaoka Y, Kabir MH, Hasan MA, et al. Virucidal activity of slightly acidic hypochlorous acid water toward influenza virus and coronavirus with tests simulating practical usage. Virus Res. 2021;297:198383. doi.org/10.1016/j.virusres.2021.198383. PMID 33705798. suspension + carrier
Hamilton AN, Chandran S, Baker CA, Gibson KE. Surface inactivation of a SARS-CoV-2 surrogate with hypochlorous acid is impacted by surface type, contact time, inoculum matrix, and concentration. Food Environ Virol. 2023;15(2):116-122. doi.org/10.1007/s12560-023-09549-0. PMID 36680664. carrier (surface)
Park GW, Boston DM, Kase JA, Sampson MN, Sobsey MD. Evaluation of liquid- and fog-based application of Sterilox hypochlorous acid solution for surface inactivation of human norovirus. Appl Environ Microbiol. 2007;73(14):4463-4468. doi.org/10.1128/AEM.02839-06. PMID 17483283. carrier (surface)
Mokudai T, Iwasawa A, Kikuchi K, Niwano Y. Bactericidal, fungicidal, and antiviral activity of highly purified hypochlorous acid water. J Microorg Control. 2026;31(2):67-72. doi.org/10.4265/jmc.31.2_67. PMID 42270376. in vitro
Odorcic S, Haas W, Gilmore MS, Dohlman CH. Fungal infections after Boston type 1 keratoprosthesis implantation: literature review and in vitro antifungal activity of hypochlorous acid. Cornea. 2015;34(12):1599-1605. doi.org/10.1097/ICO.0000000000000639. PMID 26488624. (author affiliated with the device maker) in vitro
Zhang C, Li B, Jadeja R, Hung YC. Effects of electrolyzed oxidizing water on inactivation of Bacillus subtilis and Bacillus cereus spores in suspension and on carriers. J Food Sci. 2016;81(1):M144-M149. doi.org/10.1111/1750-3841.13169. PMID 26642381. suspension + carrier
Brown L, Marshall A, Conway L, et al. Assessing the stability and sporicidal efficacy of oxidizing disinfectants. J Hosp Infect. 2024;149:22-25. doi.org/10.1016/j.jhin.2024.04.010. PMID 38705474. (authors affiliated with a disinfectant company) in vitro (EN 17126)
Palau M, Muñoz E, Lujan E, et al. In vitro and in vivo antimicrobial activity of hypochlorous acid against drug-resistant and biofilm-producing strains. Microbiol Spectr. 2022;10(5):e0236522. doi.org/10.1128/spectrum.02365-22. PMID 36190404. in vitro + animal
Aherne O, Ortiz R, Fazli MM, Davies JR. Effects of stabilized hypochlorous acid on oral biofilm bacteria. BMC Oral Health. 2022;22:415. doi.org/10.1186/s12903-022-02453-2. PMID 36127658. (industry-funded) in vitro
Harriott MM, Bhindi N, Kassis S, et al. Comparative antimicrobial activity of commercial wound care solutions on bacterial and fungal biofilms. Ann Plast Surg. 2019;83(4):404-410. doi.org/10.1097/SAP.0000000000001996. PMID 31524733. in vitro
Burian EA, Sabah L, Kirketerp-Møller K, Gundersen G, Ågren MS. Effect of stabilized hypochlorous acid on re-epithelialization and bacterial bioburden in acute wounds: a randomized controlled trial in healthy volunteers. Acta Derm Venereol. 2022;102:adv00727. doi.org/10.2340/actadv.v102.1624. PMID 35578822. randomized trial (wounds, product-specific)
Severing AL, Rembe JD, Koester V, Stuermer EK. Safety and efficacy profiles of different commercial NaClO/HClO solutions. J Antimicrob Chemother. 2019;74(2):365-372. doi.org/10.1093/jac/dky432. PMID 30388236. cell culture
Reis R, Sipahi H, Dinc O, et al. Toxicity, mutagenicity and stability assessment of simply produced electrolyzed water as a wound healing agent in vitro. Hum Exp Toxicol. 2021;40(3):452-463. doi.org/10.1177/0960327120952151. PMID 32909829. cell culture
40 CFR 180.940(a): Tolerance exemptions for active and inert ingredients for use in antimicrobial formulations (food-contact surface sanitizing solutions). www.ecfr.gov/current/title-40/chapter-I/subchapter-E/part-180/subpart-D/section-180.940. regulation
Fukuzaki S. Uses of gaseous hypochlorous acid for controlling microorganisms in indoor spaces. J Microorg Control. 2023;28(4):165-175. doi.org/10.4265/jmc.28.4_165. PMID 38233168. review
Oikawa T, et al. Rat study of long-term aerosol exposure to slightly acidic electrolyzed water (title shortened). PLoS One. 2026;21(1):e0341050. doi.org/10.1371/journal.pone.0341050. PMID 41615984. (funded by the maker, which supplied the solution; some authors are its employees) animal (inhalation)
NIOSH Pocket Guide to Chemical Hazards: Chlorine (CAS 7782-50-5). www.cdc.gov/niosh/npg/npgd0115.html. guidance
Bryant DN, Lurndahl NA, Ellis-Cramer M, et al. Impact of chemical aging on venison processing knife topography and recoverable chronic wasting disease prion seeding activity. Pathogens. 2026;15(6):645. doi.org/10.3390/pathogens15060645. PMID 42347257. (two authors co-founded a prion-diagnostics company) lab (materials)
Rahman S, Khan I, Oh DH. Electrolyzed water as a novel sanitizer in the food industry: current trends and future perspectives. Compr Rev Food Sci Food Saf. 2016;15(3):471-490. doi.org/10.1111/1541-4337.12200. PMID 33401818. review
Takeda Y, Matsuda S, Jamsransuren D, Ogawa H. Comparison of the SARS-CoV-2-inactivating activities of the differently manufactured hypochlorous acid water products with various pH. J Water Health. 2021;19(3):448-456. doi.org/10.2166/wh.2021.260. PMID 34152297. in vitro
López-Gálvez F, Andújar S, Marín A, et al. Disinfection by-products in baby lettuce irrigated with electrolysed water. J Sci Food Agric. 2018;98(8):2981-2988. doi.org/10.1002/jsfa.8796. PMID 29171869. field (greenhouse)
Kim SY, Ha JH. Formation and speciation of hazardous trihalomethanes and haloacetic acids during chlorinated washing of brined kimchi cabbage in the presence of bromide. J Hazard Mater. 2023;455:131557. doi.org/10.1016/j.jhazmat.2023.131557. PMID 37182460. lab (food processing)
Oie S, Obayashi A, Yamasaki H, et al. Disinfection methods for spores of Bacillus atrophaeus, B. anthracis, Clostridium tetani, C. botulinum and C. difficile. Biol Pharm Bull. 2011;34(8):1325-1329. doi.org/10.1248/bpb.34.1325. PMID 21804226. carrier (surface)
Slaughter RJ, Watts M, Vale JA, Grieve JR, Schep LJ. The clinical toxicology of sodium hypochlorite. Clin Toxicol. 2019;57(5):303-311. doi.org/10.1080/15563650.2018.1543889. PMID 30689457. review
PubChem (NIH/NCBI). Sodium hypochlorite, CID 23665760: Odor (HSDB) and Physical Description. pubchem.ncbi.nlm.nih.gov/compound/23665760. reference
Lauriola MM, Corazza M. Irritant and sensitizing potential of antiseptics and disinfectants: an overview. Ital J Dermatol Venerol. 2025;160(6):535-545. doi.org/10.23736/S2784-8671.25.08213-1. PMID 41091520. review
US EPA. Guidance for Products Adding Residual Efficacy Claims. www.epa.gov/pesticide-registration/guidance-products-adding-residual-efficacy-claims. guidance
Hu M, Li L, Zhang X, et al. Ingestion of surface residues dominates quaternary ammonium compounds (QACs) exposure in Chinese urban homes: evidence from silicone wristband passive sampling and urinary biomonitoring. Environ Sci Technol. 2026;60(5):3947-3960. doi.org/10.1021/acs.est.5c16557. PMID 41601271. observational (homes)
Urushidani M, Kawayoshi A, Kotaki T, et al. Inactivation of SARS-CoV-2 and influenza A virus by dry fogging hypochlorous acid solution and hydrogen peroxide solution. PLoS One. 2022;17(4):e0261802. doi.org/10.1371/journal.pone.0261802. PMID 35389997. (some authors affiliated with a disinfection company) test chamber
EPA. Can I use fogging, fumigation, or electrostatic spraying or drones to help control COVID-19? www.epa.gov/coronavirus/can-i-use-fogging-fumigation-or-electrostatic-spraying-or-drones-help-control-covid-19. guidance
NIOSH Pocket Guide to Chemical Hazards: Hydrogen peroxide (CAS 7722-84-1). www.cdc.gov/niosh/npg/npgd0335.html. reference
PubChem (NIH/NCBI). Peracetic acid, CID 6585: Physical Description (OSHA, CAMEO). pubchem.ncbi.nlm.nih.gov/compound/6585. reference
Ogunniyi AD, Dandie CE, Ferro S, et al. Comparative antibacterial activities of neutral electrolyzed oxidizing water and other chlorine-based sanitizers. Sci Rep. 2019;9:19955. doi.org/10.1038/s41598-019-56248-7. PMID 31882630. (author affiliated with an electrolyzed-water company) lab (irrigation water)
NIOSH Pocket Guide to Chemical Hazards: Chlorine dioxide (CAS 10049-04-4). www.cdc.gov/niosh/npg/npgd0116.html. reference
PubChem (NIH/NCBI). 2-Phenylphenol (ortho-phenylphenol), CID 7017: Odor (HSDB). pubchem.ncbi.nlm.nih.gov/compound/7017. reference

HOCl vs. common disinfectants

Master comparison table

Head-to-head comparisons

HOCl vs. Sodium hypochlorite (bleach)

Key differences

Where HOCl rates higher

Where bleach rates higher

HOCl vs. Quaternary ammonium (quats)

Key differences

Where HOCl rates higher

Where quats rate higher

HOCl vs. Alcohols (ethanol / isopropyl)

Key differences

Where HOCl rates higher

Where alcohol rates higher

HOCl vs. Hydrogen peroxide / accelerated HP

Key differences

Where HOCl rates higher

Where hydrogen peroxide rates higher

HOCl vs. Peracetic acid (PAA)

Key differences

Where HOCl rates higher

Where peracetic acid rates higher

HOCl vs. Chlorine dioxide (ClO₂)

Key differences

Where HOCl rates higher

Where chlorine dioxide rates higher

HOCl vs. Phenolics

Key differences

Where HOCl rates higher

Where phenolics rate higher

How we rate

Sources

One short, sourced HOCl post. Every weekday.