National Organic Standards Board

Livestock Subcommittee

Petitioned Material Proposal

Hypochlorous Acid

August 15, 2017

Summary of Petition for Hypochlorous Acid: 

Hypochlorous acid has been petitioned as a synthetic substance for addition to the National List at 

§205.603, as a topical treatment for pinkeye and wounds in livestock. 

Hypochlorous acid was previously petitioned for use as a sanitizer in crop production, in livestock 

production, and in handling. In April 2016, the NOSB recommended adding hypochlorous acid to the 

National List at § 205.601(a) As algicide, disinfectants, and sanitizer, including irrigation system cleaning 

systems; at § 205.603(a)(7) Chlorine materials—disinfecting and sanitizing facilities and equipment; and 

at §205.605(b) Chlorine materials—disinfecting and sanitizing food contact surfaces. 

The NOSB favored adding hypochlorous acid to the National List as a sanitizer because the technical 

review indicated that although hypochlorous acid is chlorine-based, it is used at a lower concentration 

and is safer for health and the environment than the other chlorine-based sanitizers already on the 

National List: namely, chlorine dioxide, sodium hypochlorite, and calcium hypochlorite.

Summary of Review:

The petition to add hypochlorous acid to the National List as a topical treatment for pinkeye and wounds 

in livestock entails different considerations than when hypochlorous acid was under review as a 

sanitizer. Livestock producers already have a number of natural (nonsynthetic) materials available for 

treatment of pinkeye and wounds. 

The July 12, 2017, technical report (TR) of hypochlorous acid for use as a topical treatment for pinkeye 

and wounds in livestock mentions many nonsynthetic materials in use for pinkeye and wounds in 

livestock: calendula, chamomile, garlic, aloe vera, seabuckthorn, kiwi fruit, chickory, St. John’s wort, 

olive, white poplar, rose, elder, navalwort, mullein, veronica, physic nut, bacterial predators, black kelp 

alginates, honey, sugar, pineapple fruit enzymes, omentum, chitosan, platelet gel, pink trumpet tree, 

Brazilian pepper tree, siam weed, echinacea, cochlearia, goldenseal, eyebright, essential oils, breast 

milk, and cod liver oil.

Personal communications with organic dairy farmers by the LS member leading the review of this 

material indicate that many use a commercially available formulation of the nonsynthetic materials aloe, 

garlic, calendula, and chamomile, and find that it works well on wounds and as an eyewash for pinkeye.

In light of the many nonsynthetic materials available and in use by organic livestock producers for 

wounds and pinkeye, the Livestock Subcommittee does not think it necessary to add a chlorine-based 

synthetic material to the National List for the same use.

Category 1: Classification 

1. Substance is for: Livestock

2. For HANDLING and LIVESTOCK use: 

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a. Is the substance _______ Agricultural or ___x____ Non-Agricultural?

 Describe reasoning for this decision using NOP 5033-2 as a guide: 

b. If the substance is Non-agricultural, is the substance _____ Non-synthetic or __x__ 

Synthetic? 

Is the substance formulated or manufactured by a process that chemically changes a 

substance extracted from naturally occurring plant, animal, or mineral sources? [OFPA 

§6502(21)] If so, describe, using NOP 5033-1 as a guide: 

HOCl is produced by electrolyzing a brine solution made with purified water and sodium chloride

3. For LIVESTOCK: Reference to appropriate OFPA category

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; toxins derived from 

bacteria; pheromones, soaps, horticultural oils, fish emulsions, treated seed, vitamins and 

minerals; livestock parasiticides and medicines and production aids including netting, tree wraps 

and seals, insect traps, sticky barriers, row covers, and equipment cleansers; or (ii) is used in 

production and contains synthetic inert ingredients that are not classified by the Administrator 

of the Environmental Protection Agency as inerts of toxicological concern?

Hypochlorous acid is petitioned as a livestock medicine.

Category 2: Adverse Impacts 

1. What is the potential for the substance to have detrimental chemical interactions with other 

materials used in organic farming systems? [§6518(m)(1)]

The 2015 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 on to 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). However, because only 

small amounts of hypochlorous acid would be used, sprayed directly onto wounds or eyes of animals, 

there would be little chance of interaction with other materials used in organic farming.

2. What is the toxicity and mode of action of the substance and of its breakdown products or any 

contaminants, and their persistence and areas of concentration in the environment? 

[§6518(m)(2)]

“In Huang’s et al., 2008 review of the scientific literature, the authors suggested that hypochlorous acid 

penetrates cell membranes and produces hydroxyl radicals, which exert their antimicrobial activity 

through the oxidation of key metabolic systems” (2015 TR, lines 253-255).

“Diluted aqueous solution of hypochlorous acid decomposes very slowly in the dark but more rapidly in 

the presence of light, particularly rapidly in full sun light, by producing hydrogen chloride and oxygen. 

Some chlorine and chloric acid may also develop. Chlorine released into the environment is distributed 

into water and preferably air.

In water and in atmosphere chlorine/hypochlorite undergoes photolysis with an estimated half-life of 1-

4 hours, depending on the time of the day. In natural water, in the presence of organic or inorganic 

compounds, the free available chlorine immediately reacts forming various chlorinated by-products e.g. 

chloramines and chloromethanes, which are mainly distributed to the hydrosphere, but are also able to 

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transfer to some extent to the atmosphere depending on their intrinsic properties. A potential for 

bioaccumulation or bioconcentration of active chlorine species can be disregarded, because of their 

water solubility and their high reactivity (2015 TR lines 602-612).

3. Describe the probability of environmental contamination during manufacture, use, misuse or 

disposal of such substance? [§6518(m)(3)]

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.

4. Discuss the effect of the substance on human health. [§6517 (c)(1)(A)(i); §6517 (c)(2)(A)(i); 

§6518(m)(4)]. 

Chlorine disinfectants have been shown to cause occupational dermatitis or skin irritation (2015 TR, line 

662). However as a wound or pinkeye spray, only a small amount of hypochlorous acid would be 

sprayed directly onto an animal, so threats to human health would be minimal.

5. Discuss any effects the substance may have on biological and chemical interactions in the 

agroecosystem, including the physiological effects of the substance on soil organisms (including 

the salt index and solubility of the soil), crops and livestock. [§6518(m)(5)] 

Because only small amounts of hypochlorous acid would be used, sprayed directly onto wounds or eyes 

of animals, there would be no chemical or biological effect on the agroecosystem, including soil 

organisms.

6. Are there any adverse impacts on biodiversity? (§205.200) 

The TR, (lines 596-612) states 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. However as a wound or 

pinkeye spray, only a small amount of hypochlorous acid would be sprayed directly onto an animal, so it 

would not contaminate water resources.

Category 3: Alternatives/Compatibility 

1. Are there alternatives to using the substance? Evaluate alternative practices as well as nonsynthetic and synthetic available materials. [§6518(m)(6)]

As noted in the 2017 TR (and above), there are many non-synthetic materials already available and

currently being used by organic livestock producers as medical treatments for livestock wounds and 

pinkeye. There are also management practices that can be used to prevent pinkeye infections, including 

fly control; bolstering animals’ immune system with vitamins, trace minerals, and kelp meal; and use of 

vaccines. 

2. For Livestock substances, and Nonsynthetic substances used in Handling: In balancing the 

responses to the criteria above, is the substance compatible with a system of sustainable 

agriculture? [§6518(m)(7)]

Given the many alternatives currently available, the Livestock Subcommittee does not think 

hypochlorous acid is a necessary material for livestock producers for treating wounds and pinkeye in 

livestock. 

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Subcommittee vote:

Motion to add hypochlorous acid at §205.603 

Motion by: Francis Thicke

Seconded by: Harriet Behar

Yes: 1 No: 5 Abstain: 0 Absent: 1 Recuse: 0

Approved by Ashley Swaffar, Subcommittee Chair, to transmit to NOSB August 29, 2017

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