Crops:SulfuricAcid

National Organic Standards Board

Crops Subcommittee

Petitioned Material Proposal

Sulfuric Acid

August 7, 2012

Introduction:

A petition was submitted requesting the addition of sulfuric acid to the National List (7 CFR 

§205.601) for stabilization of digested poultry manure to a pH under 4.5 but not below 3.5.

Background:

In 2006, a similar petition was submitted for use in digested livestock manure. The Crops 

Committee voted unanimously to reject the petition because “Sulfuric acid, when used in 

livestock manure, is changed to sulfate, which is in this case a synthetically derived plant 

nutrient. Additionally, it is an important air pollutant, e.g. acid rain. Other wholly natural 

materials can be used.” After some discussion by the NOSB at the October 18, 2006 meeting, 

and at the request of the petitioner, the vote on the petition was deferred.

Discussion:

The listing of sulfuric acid is not the only hurdle that petitioners need to clear in order to use 

their products. OMRI so far restricts the use of byproducts of anaerobic digestion of animal 

manures --used for generating methane-- to the uses allowed for raw manure. They say that 

these byproducts do not meet the NOP temperature and moisture criteria for processed 

manure. (They also do not contain the beneficial aerobic organisms that are an important 

benefit to the soil from composted manure.) Additional action by the NOSB and/or NOP will be 

needed to allow the full use of anaerobically-digested waste. (OMRI Materials Review, 

Summer 2012)

The Crops Subcommittee agrees with the 2006 vote and recommends denying the petition 

because of adverse environmental and health impacts, lack of essentiality, and incompatibility 

with organic principles, as supported by the checklist.

Evaluation Criteria:

(Applicability noted for each category; Documentation attached) Criteria Satisfied? (see 

“B” below)

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 

4. Commercial Supply is Fragile or Potentially Unavailable ☐ Yes ☐ No ☒ N/A 

as Organic (only for § 205.606)

Substance Fails Criteria Category: [1,2,3] 

Subcommittee Comments:

Adverse environmental and health impacts, lack of essentiality, and incompatibility with organic 

principles, as supported by the TR and checklist.
Crops:SulfuricAcid

Recommended Subcommittee Action & Vote, including classification recommendation 

(state actual motion):

Classification Motion: 

Sulfuric Acid is synthetic.

Motion by: Colehour Bondera Seconded by: Nick Maravell

Yes__6___ No__0__ Abstain__0__ Recuse__0__ Absent__2__

Listing Motion: 

To list on §205.601, sulfuric acid for stabilization of digested poultry manure to a pH under 

4.5 but not below 3.5.

Motion by: Harold Austin Second: Barry Flamm

Yes__0___ No__6__ Abstain__0__ Recuse__0__ Absent__2 _

Crops ☒ Agricultural ☐ Allowed1 ☐

Livestock ☐ Non-synthetic ☐ Prohibited2 ☐

Handling ☐ Synthetic ☒ Rejected3 ☒

No restriction ☐ Commercial unavailable as 

organic

☐ Deferred4 ☐

1

Substance voted to be added as “allowed” on National List to § 205. 601(h) with 

Annotation (if any): 

2

Substance to be added as “prohibited” on National List to § 205 with Annotation (if any): 

Describe why a prohibited substance: 

3

Substance was rejected by vote for amending National List to § 205. Describe why 

material was rejected: 

4

Substance was recommended to be deferred because 

If follow-up needed, who will follow up: 

Approved by Subcommittee Chair to Transmit to NOSB

Jay Feldman, Subcommittee Chair August 7, 2012
Crops:SulfuricAcid

NOSB Evaluation Criteria for Substances Added To the National List

Category 1. Adverse impacts on humans or the environment? Substance: Sulfuric Acid

Question Yes No N/A1 Documentation

(TAP; petition; regulatory agency; other)

1. Are there adverse effects on 

environment from manufacture, 

use, or disposal? 

[§205.600 b.2]

X

2. Is there environmental 

contamination during 

manufacture, use, misuse, or 

disposal? [§6518 m.3]

X

One of the primary sources of human sourced sulfuric 

acid in the environment is its manufacture. (TR, lines 

187-191) According to the TRI, in 1996, releases of 

sulfuric acid to the air from 7 14 large processing 

facilities totaled 8,929,868 kg (19,690,359 pounds) 

(TR196 1998). (ATSDR, 1998. Toxicological Profile for 

Sulfur Trioxide and Sulfuric Acid. 

http://www.atsdr.cdc.gov/toxprofiles/tp117.pdf.)

3. Is the substance harmful to 

the environment?

[§6517c(1)(A)(i);6517(c)(2)(A)i] 

X

Sulfuric acid can kill organisms. Air borne sulfuric acid 

can cause pulmonary edema (TR lines 187-200 & lines 

234-242 & lines 296-297) If sulfuric acid comes in 

contact with bodies of water the bioavailability of heavy 

metals increases. (Ostiguy). The International Agency 

for Cancer Research (IARC) has determined that there 

is sufficient evidence that occupational exposure to 

strong-inorganic-acid mists containing sulfuric acid is 

carcinogenic to humans (IARC 1992, 1997). (TR lines 

313-316)

4. Does the substance contain 

List 1, 2, or 3 inerts? 

[§6517 c (1)(B)(ii); 

205.601(m)2]

X

5. Is there potential for 

detrimental chemical interaction 

with other materials used?

[§6518 m.1]

X

Sulfuric acid can interact with other chemicals used if it 

comes in contact with the other materials. (TR lines 

187-191) Sulfuric acid, when used as a pH adjustor for 

livestock manure, is changed to sulfate, which is plant 

nutrient. (TR lines 226-227) Sulfuric acid is corrosive..

6. Are there adverse biological 

and chemical interactions in 

agro-ecosystem? [§6518 m.5]

X Sulfuric acid, when used in livestock manure, is 

changed to sulfate. (TR lines 226-227)..

7. Are there detrimental 

physiological effects on soil 

organisms, crops, or livestock? 

[§6518 m.5]

X

Sulfuric acid is corrosive and, at high concentrations, 

can kill organisms. No detrimental physiological effects 

on soil organisms, crops or livestock are expected for 

this usage. Detrimental impacts from manufacture, 

misuse, disposal. (TR lines 178-229) 

8. Is there a toxic or other 

adverse action of the material 

or its breakdown 

products?[§6518 m.2]

X

Sulfuric acid is corrosive; it can harm eyes, skin, and 

respiratory and gastrointestinal tracts. (TR lines 294-

308.) . The International Agency for Cancer Research 

(IARC) has determined that there is sufficient evidence 

that occupational exposure to strong-inorganic-acid 

mists containing sulfuric acid is carcinogenic to humans 
Crops:SulfuricAcid

(IARC 1992, 1997). (TR lines 313-316) ). (ATSDR, 

1998. Toxicological Profile for Sulfur Trioxide and 

Sulfuric Acid. 

http://www.atsdr.cdc.gov/toxprofiles/tp117.pdf.)

9. Is there undesirable 

persistence or concentration of 

the material or breakdown 

products in 

environment?[§6518 m.2]

X

Sulfuric acid is not persistent. Its breakdown products 

are sulfate ions. It can persist in the environment if the 

soil is unable to neutralize it. (TR lines 330-341)..

10. Are there any harmful 

effects on human health? 

[§6517 c (1)(A)(i) ; 6517 

c(2)(A)i; §6518 m.4]

X

Skin, eye respiratory and gastrointestinal tract irritation; 

EPA Category I toxicity; aerosol is a suspected human 

carcinogen (ACGIH); H2SO4 mist is a human 

carcinogen (IARC); protective clothing, eyewear & 

breathing protection are needed (TR lines 294-325). 

Sulfuric acid exposure also occurs when it is 

manufactured... The National Occupational Exposure 

Survey (NOES), conducted by NIOSH from 1981 to 

1983, estimated that 56,103 and 775,348 U.S. workers 

may be exposed to sulfur trioxide and sulfuric acid, 

respectively (NOES 1990).”

11. Is there an adverse effect 

on human health as defined by 

applicable Federal regulations? 

[205.600 b.3]

X

12. Is the substance GRAS 

when used according to FDA’s 

good manufacturing practices? 

[§205.600 b.5]

X

13. Does the substance contain 

residues of heavy metals or 

other contaminants in excess of 

FDA tolerances? [§205.600 b.5]

X

1

If the substance under review is for crops or livestock production, all of the questions from 205.600 (b) 

are N/A—not applicable.
Crops:SulfuricAcid

Category 2. Is the Substance Essential for Organic Production? Substance _ Sulfuric Acid _

Question Yes No N/A1 Documentation

(TR; petition; regulatory agency; other)

1. Is there a natural source of 

the substance? [§205.600 b.1]

X

2. Is there an organic 

substitute? [§205.600 b.1]

X

3. Is the substance essential 

for handling of organically 

produced agricultural 

products? [§205.600 b.6]

X

4. Is there a wholly natural 

substitute product? 

[§6517 c (1)(A)(ii)]

X

At present, the quantity of carbon material required to 

induce a significant pH decline is economically 

prohibitive. However, if the production of acid can be 

optimized, possibly by using suitable lactic acid 

bacteria, it would offer an effective and safe means to 

prevent ammonia production. (TR367-369) A variety of 

natural absorbents can be used to reduce ammonia 

production; some of the most commonly employed are 

peat and clinoptilolite (a naturally occurring aluminosilicate mineral with high cation exchange capacities). 

The advantages associated with the use of either 

clinoptilolite or peat are that they are nonhazardous and 

act as good soil conditioners when spread with manure. 

(TR371-374)

5. Is the substance used in 

handling, not synthetic, but not 

organically produced? 

[§6517 c (1)(B)(iii)]

X

6. Is there any alternative 

substances? [§6518 m.6] X

Unreacted carbon, citric acid, lactic acid bacteria or 

materials such as clay, peat, and clinoptilote. (TR lines 

356-387). 

7. Is there another practice 

that would make the 

substance unnecessary? 

[§6518 m.6]

X

Composting animal manure can also be used. 

Stabilization of animal manures can also be accomplish 

with unreacted carbon, lactic acid bacteria or materials 

such as clay, peat, and clinoptilote.(TR lines 356-387) 

Other types of approved composted materials and 

dehydrated manure can be used. ). Hall and Sullivan 

(2001) provide a review of alternative soil amendments 

to agricultural fertilizers and manure, including several 

that can be considered wholly natural, such as various 

plant byproducts (e.g., composted leaves), rock and 

mineral powders (e.g., granite dust), and seaweed 

products. (TR382-387) As specified under NOP 

§205.203(b): “The producer must manage crop 

nutrients and soil fertility through rotations, cover crops, 

and the application of plant and animal materials.” 

Thus, the need to use manure (whether composted, 

non-composted, or chemically-treated) or plant 

materials could be replaced through crop rotation and 
Crops:SulfuricAcid

use of cover crops. (TR 409-412)

1

If the substance under review is for crops or livestock production, all of the questions from 205.600 

(b)are N/A—not applicable.
Crops:SulfuricAcid

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

Substance __ Sulfuric Acid __

Question Yes No N/A1 Documentation

(TR; petition; regulatory agency; other)

1. Is the substance compatible 

with organic handling? 

[§205.600 b.2]

X

2. Is the substance consistent 

with organic farming and 

handling? [§6517 c (1)(A)(iii); 

6517 c (2)(A)(ii)]

X Sulfuric acid is the primary agent of acid rain, it is an air 

pollutant TR lines 46-50) Sulfuric acid, when used in 

livestock manure, is changed to sulfate, which is in this 

case a synthetically derived plant nutrient.TR lines 226-

227). It has been allowed in similar uses for materials 

presently on the National List.

3. Is the substance compatible 

with a system of sustainable 

agriculture? [§6518 m.7]

X Sulfuric acid is the primary agent of acid rain, it is an air 

pollutant TR lines 46-50) Sulfuric acid, when used in 

livestock manure, is changed to sulfate, which is in this 

case a synthetically derived plant nutrient. TR lines 

226-227) It has been allowed in similar uses for 

materials presently on the National List.

4. Is the nutritional quality of 

the food maintained with the 

substance? [§205.600 b.3]

X

5. Is the primary use as a 

preservative? [§205.600 b.4]

X

6. Is the primary use to 

recreate or improve flavors, 

colors, textures, or nutritive 

values lost in processing 

(except when required by law, 

e.g., vitamin D in milk)? 

[205.600 b.4]

X

7. Is the substance used in 

production, and does it 

contain an active synthetic 

ingredient in the following 

categories:

a. copper and sulfur 

compounds;

X

Sulfur compounds.

b. toxins derived from 

bacteria;

X

c. pheromones, soaps, 

horticultural oils, fish 

emulsions, treated seed, 

vitamins and minerals?

X

d. livestock parasiticides and 

medicines? X
Crops:SulfuricAcid

e. production aids including 

netting, tree wraps and seals, 

insect traps, sticky barriers, 

row covers, and equipment 

cleaners?

X

1

If the substance under review is for crops or livestock production, all of the questions from 205.600 (b) 

are N/A—not applicable.

2006 recommendation: “Describe why material was rejected: Sulfuric acid, when used in animal 

manure, is changed to sulfate, which is in this case a synthetically derived plant nutrient. Additionally, it 

is an important air pollutant, e.g., acid rain. Other wholly natural materials can be used. (See Category 

2, questions 4, 6, and 7.”