National Organic Standards Board

Livestock Subcommittee

Petitioned Material Proposal - Hypochlorous Acid 

February 16, 2016

Summary of Proposed Action:

On May 29, 2015 the NOP received a petition to add hypochlorous acid (CAS #7790-92-3) to the National 

List of synthetic substances allowed for use in organic production and handling (7 CFR §205.600-606) at 

§205.605. This material is being petitioned for use as an antimicrobial/sanitizer for use on equipment 

and raw agricultural products.

This petition has been submitted in response to a policy memo issued by the NOP on June 9, 2014: PM 

14-3 Electrolyzed Water. That was a memo issued as a response to requests asking for the National 

Organic Program to clarify whether electrolyzed water (EW) was allowed as a sanitizer and antimicrobial 

agent for use in organic production and handling.

The NOP felt that the allowance of EW by a certifier or a material evaluation program (were based on an 

incorrect interpretation of the allowance for chlorine materials on the National List of Allowed and 

Prohibited Substances at 7 CFR 205.600-606. The NOP requested that certifiers ensure that the use of 

EW was not allowed in organic handling or production and that any party wishing for further 

consideration of EW for use in organic handling or production, should then submit a petition to get it 

added to the National List. Thus, the rationale for the petition currently before the Handling

subcommittee and the full NOSB is in response to the NOP policy memo.

Manufacture and Uses of the Substance:

Electrolyzed water (EW) is the product of the electrolysis of a dilute sodium chloride solution in an 

electrolysis cell containing a semi-permeable membrane that physically separates the anode and 

cathode, but permits specific ions to pass through. In the process, hypochlorous acid, hypochlorite ion, 

and hydrochloric acid are formed at the anode, and sodium hydroxide is formed at the cathode. The 

solution formed on the anode side is acidic EW (pH 2 to 6), and the solution formed on the cathode side 

is basic EW (pH 7.5 to 13). Neutral EW, with a pH of 6 to 7.5 is produced by mixing the anodic solution 

with hydroxide, or by using a single-cell chamber for electrolysis. (TR lines 48-68)

The effectiveness of hypochlorous acid as an active sanitizing agent is determined in large part by the 

solution pH. Hypochlorous acid exists interchangeably with other chlorine species, including chlorine, 

hydrogen chloride (aqueous and gaseous) and hypochlorite. In a controlled pH environment, 

hypochlorous acid will exist as the dominant chlorine species under pH conditions ranging from 2 to 7.

(TR lines 84-89)

At a pH of 6.0-7.5 (neutral), EW contains primarily hypochlorous acid, hypochlorite ion and trace 

amounts of chlorine (TR 118-119). At pH <4.0, dissolved chlorine gas can be rapidly lost due to 

volatilization, decreasing the biocidal effectiveness of the solution over time, and also creating human 

health and safety issue (TR 150-152). Therefore it is important that neutral EW be used for sanitizing, 

not acidic EW.

EW has received recent attention as an alternative to other chlorine disinfectants and sanitizers. A 

number of studies have demonstrated the strong antibacterial activity of EW water against foodborne 

pathogens on raw agricultural products and food contact surfaces. Applications of EW as a disinfectant 

for reducing microbial contamination have been reported for fresh fruits and vegetables, poultry 

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carcasses, shell eggs, cutting boards, and food processing surfaces. Some advantages of using EW water 

are: 1) EW is as effective as any chlorine treatment, 2) it is not necessary to handle potentially 

dangerous chemicals, e.g. chlorine gas, chlorine dioxide, bleach, 3) the apparatus to produce EW is 

relative inexpensive and easy to operate, 4) because only water and sodium chloride are used EW 

production is environmentally friendly and 5) the properties of the EW can be controlled at the 

preparation site. (TR lines 99-108)

Discussion:

In general, neutral hypochlorous acid (EW) at pH 6.5-7.5 is safer to use than other chlorine-containing 

disinfectants. The concentration of chlorine present in electrolyzed water is usually over ten thousand 

times less than household bleach. There is also the advantage of its production on site, alleviating the 

need to transport dangerous material. (TR lines 616-619)

Hypochlorous acid is the same active sanitizing ingredient that is present in sodium hypochlorite and 

calcium hypochlorite. The reason hypochlorous acid can be ten thousand times less concentrated than 

sodium and calcium hypochlorite solutions and still be an effective sanitizer is that sodium and calcium 

hypochlorite solutions (bleach) have a high pH. When the pH is high, the hypochlorous acid/hypochlorite 

chemical equilibrium strongly shifts towards the presence of hypochlorite, whereas at neutral pH the 

chemical equilibrium shifts towards the presence of hypochlorous acid, the effective sanitizing 

compound. Therefore, hypochlorous acid (EW) is a safer product, for the environment and for human 

health, than chlorine sanitizer materials currently on the National List.

Evaluation Criteria 

 Criteria Satisfied? 

1. Impact on Humans and Environment ☒ Yes ☐ No ☐ N/A 

2. Essential & Availability Criteria ☒ Yes ☐ No ☐ N/A

3. Compatibility & Consistency ☒ Yes ☐ No ☐ N/A 

Classification Motion: Move to classify hypochlorous acid as synthetic. 

Motion by: Francis Thicke 

Seconded by: Jean Richardson 

Yes: 8 No: 0 Abstain: 0 Absent: 0 Recuse: 0

Listing Motion: Move to list hypochlorous acid as petitioned at §205.603 of the National List (a) As 

disinfectants, sanitizer, and medical treatments as applicable. (7) Chlorine materials—disinfecting 

and sanitizing facilities and equipment. Residual chlorine levels in the water shall not exceed the 

maximum residual disinfectant limit under the Safe Drinking Water Act. (iv) hypochlorous acid.

Motion by: Francis Thicke 

Seconded by: Jesse Buie

Yes: 7 No: 0 Abstain: 1 Absent: 0 Recuse: 0

 

Approved by Ashley Swaffar, Livestock Subcommittee Chair, to transmit to NOSB February 16, 

2016

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NOSB Evaluation Criteria for Substances Added To the National List - Livestock

Category 1. Adverse impacts on humans or the environment? Hypochlorous acid

Question Yes No N/A Comments/Documentation (TAP; petition; 

regulatory agency; other)

1. Is there a probability of 

environmental contamination 

during use or misuse? 

[§6518(m)(3)]

x According to the petition electrolyzed water 

can be made on-site. In this process there 

would not be any residual product to dispose 

of. If produced off-site and sold as a finished 

product then there could be a possibility of 

environmental contamination as the result of 

an accident or a spill. The TR does state that 

in forms of hypochlorous acid that are at a 

pH<4.0, dissolved chlorine gas can be rapidly 

lost due to volatilization, decreasing the 

biocidal effectiveness of the solution over 

time, but also creating possible human 

health and safety issues (Fisher, 2009). The 

more neutral, the pH of the material, the 

safer and more stable the substance appears 

to become.

2. Is there a probability of 

environmental contamination 

during, manufacture or disposal? 

[§6518(m)(3)]

x This substance is formed by the electrolysis 

of a sodium chloride solution. Any 

environmental concerns would be from a 

spill during manufacturing or transport of a 

formulated end product.

3. Are there any adverse impacts on 

biodiversity? (§205.200)

x The TR, (lines 596-612) does state that 

hypochlorous acid in aqueous solutions at 

pH< 7. Was of minimal toxicity to birds, but 

could be very toxic to fish and freshwater 

invertebrates. 

4. Does the substance contain inerts 

classified by EPA as ‘inerts of 

toxicological concern’? [§6517 

(c)(1)(B)(ii)]

x Contaminants listed in the US Food and Drug 

Administration’s Guidance for Industry: 

Action Levels for Poisonous or Deleterious 

Substances in Human Food and Animal Feed, 

are unlikely to be found in hypochlorous acid 

since it is the electrolysis product of two 

generally recognized as safe materials, salt 

and water (TR lines 568-571).

5. Is there potential for detrimental 

chemical interaction with other 

materials used in organic farming 

systems? 

[§6518(m)(1)]

x The TR (lines 140-153) mentions that there 

can be a reaction with organic material 

(humic acid) which can lead to some 

potential concerns. It does go onto state 

though: It is generally accepted that 

carcinogenic and teratogenic 

trihalomethanes and haloacetic acids are not 

formed by the action of hypochlorous acid in 

neutral or near-neutral solutions (Satyawli et 

al., 2007). 

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6. Is there a toxic or other adverse 

action of the material or its 

breakdown products?

[§6518(m)(2)]

x

7. Is there persistence or 

concentration of the material or 

breakdown products in the 

environment? [§6518(m)(2)]

x According to the TR (lines 602-612) 

hypochlorous acid solution decomposes very 

slowly in the dark but more rapidly in the 

presence of light, rapidly in full sun light by 

producing hydrogen chloride and oxygen. 

Released into the environment it is 

distributed into water and air, with an 

estimated half-life of 1-4 hours. A potential 

for bioaccumulation or bioconcentration of 

active chlorine species can be disregarded, 

because of their water solubility and their 

high reactivity.

8. Would the use of the substance 

be harmful to human health or 

the environment? [§6517 

(c)(1)(A)(i); §6517 (c)(2)(A)(i); 

§6518(m)(4)]

x Information provided in the petition states 

that compared to other types of chlorine, 

electrolyzed water is usually used at an 

active rate that is ten thousand times less 

than that of common household bleach. The 

TR (lines 624-626) mentions that the human 

innate immune system uses hypochlorous 

acid to fight infection but also directs it 

against host tissue in inflammatory diseases 

(Kettle et al.,2013). Chlorine disinfectants 

have been shown to cause occupational 

dermatitis or skin irritation (TR line 662).

9. Are there adverse biological and 

chemical interactions in the agroecosystem? [§6518(m)(5)]

x See the answer to question #5 above.

10. Are there detrimental 

physiological effects on soil 

organisms, crops, or livestock? 

[§6518(m)(5)]

x

Category 2. Is the Substance Essential for Organic Production? Hypochlorous acid

Question Yes No N/A Comments/Documentation 

(TAP; petition; regulatory 

agency; other)

1. Is the substance agricultural? [§6502(1)] x

2. Is the substance formulated or manufactured by 

a chemical process? [§6502(21)]

x Electrolyzed water is the 

product of the electrolysis of a 

dilute sodium chloride solution 

in an electrolysis cell containing 

a semi-permeable membrane. 

This process creates 

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hypochlorous acid, hypochlorite 

ion, and hydrochlorite at the 

anode and sodium hydroxide at 

the cathode. (TR lines 48-68) 

August 13, 2015 TR.

3. Is the substance formulated or manufactured by 

a process that chemically changes a substance 

extracted from naturally occurring plant, animal, 

or mineral sources? 

[§6502(21)]

x

4. Is the substance created by naturally occurring 

biological processes? [§6502(21)]

x

5. Is there a natural source of the substance? 

[§ 205.600(b)(1)]

x

6. Is there an organic substitute? 

[§205.600(b)(1)]

x Organic acids such as citric acid, 

lactic acid, malic acid, and 

vinegar are some alternative 

materials. 

7. Is there a wholly natural substitute product?

[§6517(c)(1)(A)(ii)]

x Hot water can be used in some 

instances. 

8. Are there any alternative substances? 

[§6518(m)(6)]

x Some alternative substances 

are: Sodium and/or calcium 

hypochlorite (bleach), 

isopropanol, chlorine dioxide, 

peroxyacetic acid, citric acid, 

acetic acid, ascorbic acid, and 

vinegar. Copper sulfate is 

another possible alternative 

depending on the use. 

9. Are there other practices that would make the 

substance unnecessary? [§6518(m)(6)]

x

Category 3. Is the substance compatible with organic production practices? Hypochlorous acid 

Question Yes No N/A Comments/Documentation (TAP; petition; 

regulatory agency; other)

1. Is the substance consistent with 

organic farming and handling? 

[§6517(c)(1)(A)(iii); 6517(c)(2)(A)(ii)]

x Compared to many of the alternative 

materials currently being used electrolyzed 

water could provide a safer and effective 

alternative. (especially when produced 

using the on-site electrolysis process)

2. Is the substance compatible with a 

system of sustainable agriculture? 

[§6518(m)(7)]

x See answer to question #1 of this category.

3. If used in livestock feed or pet food, is

the nutritional quality of the food 

maintained with the substance? 

[§205.600(b)(3)]

x

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4. If used in livestock feed or pet food, is

the primary use as a preservative? 

[§205.600(b)(4)]

x

5. If used in livestock feed or pet food, is

the primary use to recreate or 

improve flavors, colors, textures, or 

nutritive value lost in processing 

(except when required by law)? 

[§205.600(b)(4)]

x

6. Is the substance used in production, 

and does it contain an active synthetic 

ingredient in the following categories: 

[§6517(c)(1)(B)(i);

copper and sulfur compounds

x

toxins derived from bacteria x

pheromones, soaps, horticultural 

oils, fish emulsions, treated seed, 

vitamins and minerals

x

livestock parasiticides and 

medicines

x

production aids including netting, 

tree wraps and seals, insect traps, 

sticky barriers, row covers, and 

equipment cleansers

x May be used to sanitize equipment

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