National Organic Standards Board 

Crops Subcommittee 

Petitioned Material Proposal 

Stabilized Hydronium used as a processing aid in organic crop production 

July 23, 2021 

Summary of Petition: 

Hydronium is being petitioned for use as a processing aid for pH adjustment not below 5.0 and as a 

stabilizer in the production of animal manures. It would be used to reduce malodorous properties of 

manures. 

Summary of Review: 

A survey of regulations for organic production from a number of countries and international 

organizations indicates that hydronium is not included within the Canadian Organic Standards as an 

allowed material. CODEX Alimentarius does not include a listing for hydronium nor is there a listing in 

the Japan Agricultural Standard (JAS) for Organic Production. Based on data submitted by the 

manufacturer, hydronium acts as a biocide but has not been approved by the EPA for that use. 

Category 1: Classification 

1. For CROP use: 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. 

Hydronium is a mixture of sulfuric acid and calcium hydroxide. The sulfuric acid is produced from 

sulfur dioxide collected in pollution control scrubbers and the calcium hydroxide is produced by 

hydrating calcium oxide. Hydronium is a manufactured compound. 

2. 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? 

Hydronium was petitioned as an allowed synthetic substance for addition to the National List at 7 

CFR §205.601 (j) 7. Hydronium is used as a production aid and although it contains sulfur, very little 

sulfur is left in the final product. 

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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)] 

As described in the petition, hydronium would be used in small amounts as an addition to manures 

during processing and would not be expected to cause detrimental chemical interactions. 

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)] 

The compounds used to produce hydronium are listed as "food grade" and the company states that 

there are no hazardous compounds generated as by-products. 

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

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

The technology used to produce hydronium is rated as "non-hazardous" as rated by 3rd party 

testing and EPA 6-pack testing. There is no discharge waste material or air emissions during 

production. The probability of environmental contamination during production is low. 

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

§6518(m)(4)]. 

Based on EPA 6-pack testing hydronium is rated as non-hazardous, has a corrosivity rating similar to 

distilled water and does not induce amide hydrolysis on plant, animal, or human tissue. 

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)] 

Hydronium is used in very small quantities and would not be expected to have any physiological 

effects on soil organisms or interact with chemicals in the agroecosystem. 

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

Data submitted in the proposal demonstrates that hydronium has biocide properties, and the 

petitioner has requested that designation of the product from the EPA. To date, it has not been 

approved by the EPA. Because hydronium is a biocide it is expected to have an impact on the 

biodiversity of soil microorganisms with unknown effects. 

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)] 

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OMRI lists over 2,000 pH adjustment aids/acidic compounds. Although many of them would 

probably not be applicable to the process of odor control of manure many organic acids could 

probably perform as hydronium is described. 

2. In balancing the responses to the criteria above, is the substance compatible with a system of 

sustainable agriculture? [§6518(m)(7)] 

No. Based on OPFA criteria and improving soil health, the biocide activity of this product and the 

lack of EPA approval make it incompatible with a system of sustainable agriculture. 

Classification Motion: 

Motion to classify hydronium as synthetic 

Motion by: Rick Greenwood 

Seconded by: Amy Bruch 

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

National List Motion: 

Motion to add hydronium to the National List at 205.601(j)(7) as an organic processing aid 

Motion by: Rick Greenwood 

Seconded by: Steve Ela 

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

Approved by Rick Greenwood, Crop Subcommittee Chair, to transmit to NOP July 31, 2021. 

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