This is a work product of the National Organic Standards Board (NOSB). It does not represent official National 

Organic Program (NOP) positions or policy.

National Organic Standards Board

Crops Subcommittee

Petitioned Material Proposal

Indole-3-butyric acid (IBA) CAS#133-32-4

January 29, 2013

Summary of Proposed Action:

Indole-3-butyric acid (IBA) CAS#133-32-4 was petitioned in 2009 and was reviewed in 

2011 by the NOSB, which voted to not add it to the National List. The petitioner repetitioned the substance in 2012, this time with a use restriction to rooting cuttings. Besides 

the use restriction, no new information accompanied the re-petition.

IBA is a plant hormone in the auxin family and is an ingredient in many commercial 

horticultural plant rooting products. IBA is not soluble in water and it is typically dissolved in 

75% or purer alcohol for use in plant rooting, making a solution of between 10,000 to 

50,000 ppm. This alcohol solution is then diluted with distilled water to the desired 

concentration. IBA is also available as a salt, which is soluble in water. This compound had 

been classified as synthetic; however, it was reported that the compound was isolated from 

leaves and seeds of maize and other species. 

IBA is used to promote strong rooting and root growth, which users say has the benefit of

minimizing the period of time in which young planting stock is susceptible to disease and 

pest pressure, thereby minimizing additional pest and disease control measures and crop 

losses. It also provides for propagation of seedless annual crops and some perennial crops 

impossible or nearly so without such support. Additionally, unique flavors of individual 

plants (e.g. mint, basil) can be precisely propagated whereas propagation by seed creates 

variability in flavors of sexually propagated stock. Proponents of IBA’s inclusion on the 

National List say it would also allow propagation materials to be sold as organic within a 12-

month time frame, thus further developing the supply to build the market for organic 

perennial planting stock on a regular basis. Its utility in the ornamental crop sector is 

widespread and may encourage ornamental nurseries to work toward developing organic 

crop production systems. Five growers provided their written support as part of the petition 

packet in favor of the including of the material to facilitate the production of organic herbs, 

strawberries, herb transplants, and other crops, and they appear to have a real interest in 

the inclusion of IBA on the National List. 

IBA’s status as a production aid (as opposed to pest control or disinfectant, for example) 

places it in uncertain territory relative to the National List and makes it difficult to categorize. 

Additionally, there was little call from organic growers for the material to be placed on the 

National List and the Crops Subcommittee would like to hear additional comments from the 

organic growing community as to need and compatibility of the material. 

The committee found that it is not essential and is not compatible with organic production.
Revised March 2012

Evaluation Criteria 

(Applicability noted for each category; Documentation attached) Criteria 

Satisfied? 

1. Impact on Humans and Environment x Yes ☐ No 

☐ N/A 

2. Essential & Availability Criteria ☐ Yes x No 

☐ N/A

3. Compatibility & Consistency ☐ Yes x No 

☐ N/A 

4. Commercial Supply is Fragile or Potentially Unavailable ☐ Yes ☐ No 

x N/A 

as Organic (only for § 205.606)

Substance Fails Criteria Category: [2, 3] Comments: There has not been shown to be a 

demonstrated need for IBA in organic production. The majority of the subcommittee found 

that synthetic materials to achieve propagation are inconsistent with organic production. In

addition, although #1 is checked yes, environmental impacts may be greater than indicated 

in the review depending on the raw materials used and the manufacturing process. 

Proposed Annotation (if any): 

Basis for annotation: ☐ To meet criteria above ☐ Other regulatory criteria ☐

Citation 

Notes: 

Recommended Committee Action & Vote, including classification recommendation (state 

actual motion):

Classification Motion: Classify IBA as synthetic.

Motion by: John Foster Seconded by: Harold Austin

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

Listing Motion: List IBA (CAS# 133-32-4) as petitioned on §205.601 for the purpose of 

plant propagation via dipping.

Motion by: John Foster Seconded by: Harold Austin

Yes: 3 No: 5 Absent: 0 Abstain: 0 Recuse:0

Crops x Agricultural ☐ Allowed1 ☐

Livestock ☐ Non-synthetic ☐ Prohibited2 ☐

Handling ☐ Synthetic x Rejected3 x

No restriction ☐ Commercial unavailable as 

organic

☐ Deferred4 ☐

1

Substance voted to be added as “allowed” on National List to § 205. with Annotation 

(if any): 

2

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

any): 
Revised March 2012

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 January 29, 2013

NOSB Evaluation Criteria for Substances Added To the National List

Category 1. Adverse impacts on humans or the environment? Substance: Indole-3-

butyric acid (IBA) 

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]

N/A

2. Is there environmental 

contamination during 

manufacture, use, misuse, or 

disposal? [§6518 m.3]

X TR 227- Petitioner stated IBA is a 

technical grade synthesized 

substance from many sources.186 

products containing IBA are available 

in US. IBA is manufactured 

worldwide. Thus, there might be 

different manufacturing procedures. 

TR 240 Isopropyl ether is listed as 

“UN1159 Flammable Liquid” by U.S. 

DOT. The health effects are listed in 

240 OSHA as “Irritation-Eye, Nose, 

Throat, Skin --- Mild (HE15).”

3. Is the substance harmful to the 

environment and biodiversity?

[§6517c(1)(A)(i);6517(c)(2)(A)i

] 

X TR 282- IBA is synthesized in 

natural plants and produced by soil 

bacteria. It is non-toxic to avian 

wildlife, plants, but slightly toxic to 

fish and aquatic, and invertebrates 

and should not cause adverse effects 

to mammalian wildlife. EPA says IBA 

does not persist in the environment. 

TR 221 EPA also waived most tox 

requirements. TR 252-255 – IBA has 

typical hormonal dose-response 

pattern. TR 287- PAN data base 

shows no evidence of harmful effects 

to environment, except slight toxicity 

to fish.
Revised March 2012

Question Yes No N/A1 Documentation (TAP; petition; 

regulatory agency; other)

4. Does the substance contain 

List 1, 2 or 3 inerts? [§6517 c 

(1)(B)(ii); 205.601(m)2]

X TR 238- Indole (CAS#120-72-9) 

butyrolactone (CAS# 96-48-0) and 

Sodium Hydroxide (CAS# 1310-73-2) 

were on EPA inerts list 4B.

5. Is there potential for 

detrimental chemical 

interaction with other materials 

used?

[§6518 m.1]

X TR 246- potentially reacts with strong 

oxidizers. TR 249- 250: “The 

stimulating effect of IBA is synergistic 

with other chemicals and bacteria.”

6. Are there adverse biological 

and chemical interactions in 

agro-ecosystem? [§6518 m.5]

X TR 262-264: The literature about 

IBA’s potentially detrimental chemical 

interaction with other substances 

used in organic crop or livestock 

production is scarce.

7. Are there detrimental 

physiological effects on soil 

organisms, crops, or 

livestock? [§6518 m.5]

X TR 272-274: The literature about 

potential detrimental physiological 

effects is limited. Instead, indole 

derivatives including IBA possess 

fungicidal activity against some plant 

pathogenic fungi (Abdel-Aty, 2010). 

(Nothing stated about effects on 

beneficial fungi.)

8. Is there a toxic or other 

adverse action of the material 

or its breakdown products?

[§6518 m.2]

X See # 3 above

9. Is there undesirable 

persistence or concentration of 

the material or breakdown 

products in environment? 

[§6518 m.2]

X See # 3 above

10.Is there any harmful effect on 

human health? [§6517 c 

(1)(A)(i); 6517 c(2)(A)i; §6518 

m.4]

X TR 303-313: EPA says no known 

risks to human health and has 

granted an exemption for tolerance of 

residue, but has waived many data 

requirements.

IBA is an “acute health hazard” 

under Section 311/312 Hazard class 

of SARA Title III Rules (MSDAIBA,2007)

11.Is there an adverse effect on 

human health as defined by 

applicable Federal 

regulations? [205.600 b.3]

N/A

12.Is the substance GRAS when 

used according to FDA’s good 

manufacturing practices? 

[§205.600 b.5]

N/A
Revised March 2012

Question Yes No N/A1 Documentation (TAP; petition; 

regulatory agency; other)

13.Does the substance contain 

residues of heavy metals or 

other contaminants in excess 

of FDA tolerances? [§205.600 

b.5]

N/A

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.

NOSB Evaluation Criteria for Substances Added To the National List

Category 2. Is the Substance Essential for Organic Production? Substance: Indole-3-

butyric acid (IBA)

Question Yes No N/A1 Documentation (TAP; petition; 

regulatory agency; other)

1. Is the substance formulated or 

manufactured by a chemical 

process? [6502 (21)]

X

2. 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

3. Is the substance created by naturally 

occurring biological processes? 

[6502 (21)]

X TR 294-296

4. Is there a natural source of the 

substance? [§205.600 b.1]

N/A

5. Is there an organic substitute? 

[§205.600 b.1]

N/A

6. Is the substance essential for 

handling of organically produced 

agricultural products? [§205.600 b.6]

N/A

7. Is there a wholly natural substitute 

product?

[§6517 c (1)(A)(ii)]

X X TR 62, 142-155: IBA occurs naturally, 

but there is not any commercially 

available extraction process. The 

most commonly used auxin for 

inducing adventitious rooting is IAA, 

but the availability of natural sources 

is unclear.

8. Is the substance used in handling, not 

synthetic, but not organically 

produced?

[§6517 c (1)(B)(iii)]

N/A

9. Are there any alternative substances? 

[§6518 m.6]

X TR 314-500 identifies many 

substances and practices.
Revised March 2012

10.Is there another practice that would 

make the substance unnecessary? 

[§6518 m.6]

X TR 314-500 identifies many 

substances and practices. Successful 

rooting from stem cuttings depend on 

many factors: timing, types of cutting, 

light, temperature, moisture and 10 

other factors including plant 

hormones.( which may be produced 

naturally by the plant tissues)

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.

NOSB Evaluation Criteria for Substances Added To the National List

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

Substance: Indole-3-butyric acid (IBA)

Question Yes No N/A1 Documentation (TAP; petition; 

regulatory agency; other)

1. Is the substance compatible with 

organic handling? [§205.600 b.2]

N/A

2. Is the substance consistent with 

organic farming and handling? [§6517 

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

X X TR 381- European and N. American 

organic regulations do not allow use 

of synthetic products forpropagation. 

It does not fit any of the allowed 

categories for approving synthetic 

inputs: 6517c1(B). However, 

proponents say it does promote 

healthy plant tissue thereby reducing 

needs for further intervention 

measures.

3. Is the substance compatible with a 

system of sustainable agriculture? 

[§6518 m.7]

X IBA is produced in plants and soil 

bacteria. There is no evidence that 

chemical properties of synthetic IBA 

are different from natural sources, but 

the manufactured IBA contains 

impurities.

4. Is the nutritional quality of the food 

maintained with the substance? 

[§205.600 b.3]

N/A

5. Is the primary use as a preservative? 

[§205.600 b.4]

N/A

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]

N/A

7. Is the substance used in production, 

and does it contain an active 

synthetic ingredient in the following 

X
Revised March 2012

categories:

a. copper and 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

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.

NOSB Evaluation Criteria for Substances Added To the National List

Category 4. Is the commercial supply of an agricultural substance as organic, fragile 

or potentially unavailable? [§6610, 6518, 6519, 205.2, 205.105 (d), 205.600 (c) 205.2, 

205.105 (d), 205.600 (c)] Substance: Indole-3-butyric acid (IBA)

Question Yes No N/A1 Documentation (TAP; petition; 

regulatory agency; other)

1. Is the comparative description 

provided as to why the non-organic 

form of the material /substance is 

necessary for use in organic 

handling? 

x

2. Does the current and historical 

industry information, research, or 

evidence provided explain how or 

why the material /substance cannot 

be obtained organically in the 

appropriate form to fulfill an essential 

function in a system of organic 

handling? 

x

3. Does the current and historical 

industry information, research, or 

evidence provided explain how or 

why the material /substance cannot 

be obtained organically in the 

appropriate quality to fulfill an 

essential function in a system of 

organic handling? 

x

4. Does the current and historical 

industry information, research, or 

evidence provided explain how or 

why the material /substance cannot 

be obtained organically in the 

x
Revised March 2012

appropriate quantity to fulfill an 

essential function in a system of 

organic handling?

5. Does the industry information 

provided on material / substance 

non-availability as organic, include ( 

but not limited to) the following:

a. Regions of production (including 

factors such as climate and 

number of regions);

x

b. Number of suppliers and amount 

produced;

x

c. Current and historical supplies 

related to weather events such as 

hurricanes, floods, and droughts 

that may temporarily halt 

production or destroy crops or 

supplies; 

x

d. Trade-related issues such as 

evidence of hoarding, war, trade 

barriers, or civil unrest that may 

temporarily restrict supplies; or

x

e. Are there other issues which may 

present a challenge to a 

consistent supply?

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.