FORMAL RECOMMENDATION BY THE

NATIONAL ORGANIC STANDARDS BOARD (NOSB) 

TO THE NATIONAL ORGANIC PROGRAM (NOP) 

Date: _ November 30, 2007____

Subject: __Aqueous Potassium Silicate (as plant disease control)

Chair: _Andrea M. Caroe_______________ 

 

Recommendation

The NOSB hereby recommends to the NOP the following: 

Rulemaking Action: __X____

Guidance Statement: ________ 

Other: ________ 

Statement of the Recommendation (including Recount of Vote):

To add aqueous potassium silicate as plant disease control to §205.601(i) Synthetic substances 

allowed for use in organic crop production 

NOSB Vote: Motion: G. Davis Second: J. Moyer 

Board vote: Yes - 15 No- 0 Abstain- 0 Absent - 0 

Rationale Supporting Recommendation (including consistency with OFPA and NOP):

Public comment at Nov. 2007 NOSB meeting well supported listing the substance as plant 

disease control by providing historical 2003 NOSB consideration of the material as well as more 

information from petitioner and other interested stakeholders. 

Sunset Material Vote 

Response by the NOP:
Decision Sheets 

December 2006 

NOSB COMMITTEE RECOMMENDATION 

Form NOPLIST1. Committee Transmittal to NOSB 

For NOSB Meeting: ___November 2007____ Substance: __Aqueous Potassium Silicate__________

Committee: Crops X Livestock  Handling  Petition is for: Use as plant disease control §205.601(i), as 

insecticide §205.601(e), and as plant or soil amendments (for hydroponic use) §205.601(j) on the National List . 

A. Evaluation Criteria (Applicability noted for each category; Documentation attached) Criteria Satisfied? (see B below) 

1. Impact on Humans and Environment 

insecticide §205.601(e) Yes √ No  N/A 

plant disease control §205.601(i) Yes √ No  N/A 

plant or soil amendments (for hydroponic use) §205.601(j) Yes √ No  N/A 

2. Essential & Availability Criteria 

insecticide §205.601(e) Yes  No √ N/A  (Dissenting member – yes) 

plant disease control §205.601(i) Yes  No √ N/A  (Dissenting member – yes) 

plant or soil amendments (for hydroponic use) §205.601(j) Yes  No √ N/A 

3. Compatibility & Consistency 

insecticide §205.601(e) Yes  No √ N/A  (Dissenting member – yes) 

plant disease control §205.601(i) Yes  No √ N/A  (Dissenting member – yes) 

plant or soil amendments (for hydroponic use) §205.601(j) Yes  No √ N/A 

4. Commercial Supply is Fragile or Potentially Unavailable as Organic (only for 606) Yes  No  N/A √ 

B. Substance Fails Criteria Category: ___2 & 3 _ Comments: 

Majority:_Criteria #2 - multiple substitutes are available Criteria #3 – synthetic soil applied fertilizers not compatible with 

organic farming regulations

Minority: As insecticide and plant disease control, the material favorably satisfies Criteria 1, 2, and 3 and should be added to 

the National List. Information provided in TAP report amply supports prohibition of the material as plant or soil amendment, but 

does not provide ample support for failing any of the evaluation criteria for the material as insecticide or plant disease control.

Previous NOSB Crops Committee (2003) voted 4-0 to approve these uses. At May 2003 NOSB meeting, material was 

deferred for later vote pending eventual EPA pesticide registration. 

 

C. Proposed Annotation (if any): No industrial by-products allowed in manufacture. 

________________________________________________________________________________________________________ 

 Basis for annotation: To meet criteria above: _______ Other regulatory criteria: _______ Citation:______________________ 

D. Recommended Committee Action & Vote (State Actual Motion): Add aqueous potassium silicate on the National List 

for use as: 

insecticide §205.601(e)- Motion: GD Seconded: JM Yes: 1 No: 3 Absent: 2

plant disease control §205.601(i)- Motion: GD Seconded: JM Yes: 1 No: 3 Absent: 2 

plant or soil amendments (for hydroponic use) §205.601(j)- Motion: GD Seconded: JM Yes: 0 No: 4 Absent: 2 

Motion by: _______________ Seconded:________________ Yes: _____ No: _____ Absent: _______ Abstain: _____ 

 

 

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) _________________________ 

________________________________________________________________________________________________________ 

Crops X Agricultural Allowed1

 

Livestock Non-Synthetic Prohibited2 

Handling Synthetic X Rejected3 X 

No restriction Commercially UnAvailable as Organic1

 Deferred4 
Decision Sheets 

December 2006 

Describe why a prohibited substance:__________________________________________________________________________

________________________________________________________________________________________________________ 

 

3) Substance was rejected by vote for amending National List to § 205. 601_ Describe why material was rejected: 

Failed evaluation criteria 2 & 3________ 

4) Substance was recommended to be deferred because ___________________________________________________________

_____________________________________________________________________________ If follow-up needed, who will 

follow up ________________________________________________________________________________________________

E. Approved by Committee Chair to transmit to NOSB: 

______Gerald Davis_________ _____9/21/07_____________ 

 Committee Chair Date
Decision Sheets 

December 2006 

NOSB EVALUATION CRITERIA FOR SUBSTANCES ADDED TO THE NATIONAL LIST

Category 1. Adverse impacts on humans or the environment? Substance – Aqueous Potassium Silicate

Question Yes No N/A

1

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 

The manufacturing process does not appear to pose a substantial risk of 

environmental contamination other than the combustion of fossil fuels to power 

the reaction. Annotation to prohibit the use of industrial byproducts in 

manufacture would be needed. Proper use and disposal of the material is unlikely 

to cause risk to the environment. (TAP pg4, item #3). Unlikely environmental 

contamination except for the possibility of harm to aquatic species if bulk 

material was improperly disposed of in a body of water. 

3. Is the substance harmful to the 

environment? 

[§6517c(1)(A)(i);6517(c)(2)(A)i] 

X 

Material has no known chronic hazards and applications will not 

result in any environmentally persistent byproducts.(TAP pg3, 

item #2) 

4. Does the substance contain List 

1, 2, or 3 inerts? 

[§6517 c (1)(B)(ii); 205.601(m)2] 

X X 

The revised petition (2006) states that the material is on EPA List 4B. 

The TAP report (2003) states that potassium silicate is on EPA List 3. 

5. Is there potential for detrimental 

chemical interaction with other 

materials used? 

[§6518 m.1] 

X 

Little or no adverse reactions expected. High solution pH of spray 

mixture can be mitigated with acidifying materials from The Allowed 

Substance List for use with alkaline sensitive materials or alkali 

sensitive plants. (TAP pg3 & pg11, item #1) 

6. Are there adverse biological and 

chemical interactions in agroecosystem? [§6518 m.5] 

X 

Not when used as foliar applied disease control or insecticide. 

Successive silicate fertilizer application could raise soil pH to 

levels that adversely affect plant growth. (TAP pg 5, item #5) 

7. Are there detrimental 

physiological effects on soil 

organisms, crops, or livestock? 

[§6518 m.5] 

X 

Same as question # 6. 

8. Is there a toxic or other adverse 

action of the material or its 

breakdown products? 

[§6518 m.2] 

X 

See question # 3. 

9. Is there undesirable persistence 

or concentration of the material or 

breakdown products in 

environment?[§6518 m.2] 

X 

Breakdown products of the material are naturally occurring in 

practically all animal species and ecosystems. Dissolved 

potassium and silica species are indistinguishable from their 

naturally occurring analogs. (TAP pg 3, item #2) 

10. Is there any harmful effect on 

human health? 

[§6517 c (1)(A)(i) ; 6517 c(2)(A)i; 

§6518 m.4] 

X 

The effects of potassium silicate applications on human health 

are likely to be minimal. Proper skin and respiratory protection 

for spray applicators of the material would be required to prevent 

acute overexposure. (TAP pg4, item # 4) 

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. 
Decision Sheets 

December 2006 
Decision Sheets 

December 2006 

Category 2. Is the Substance Essential for Organic Production? Substance - Aqueous Potassium Silicate

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 

TAP pg 2 

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 

TAP pg 2 Aqueous potassium silicate is manufactured using a 

calcination process that combines natural silica sand and 

potassium carbonate at high temperatures. The two substances 

fuse into glass, which is dissolved with high pressure steam to 

form a clear, slightly viscous liquid. 

3. Is the substance created by 

naturally occurring biological 

processes? [6502 (21)] 

X 

Aqueous potassium silicate does not occur in nature. 

4. Is there a natural source of the 

substance? [§205.600 b.1] 

X 

5. Is there an organic substitute? 

[§205.600 b.1] X 

6. Is the substance essential for 

handling of organically produced 

agricultural products? [§205.600 

b.6] 

 

 

X 

7. Is there a wholly natural 

substitute product? 

[§6517 c (1)(A)(ii)] 

X X 

Bacillus subtilis, Bacillus pumilus, milk, whey, canola oil, rosemary oil, garlic 

oil and neem oil. Botanical insecticides such as neem or pyrethrin. Effective 

natural fungicides and insecticides are very limited in number and 

effectiveness. As silica soil amendments, greensand, wollastonite, various 

other rock dusts. 

8. Is the substance used in 

handling, not synthetic, but not 

organically produced? 

[§6517 c (1)(B)(iii)] 

 

X 

9. Is there any alternative 

substances? [§6518 m.6] 

 

X 

Sulfur and copper as fungicides, horticultural oils as 

fungicides and insecticides. 

10. Is there another practice that 

would make the substance 

unnecessary? [§6518 m.6] 

X 

Variety selection, green manure cover crops and crop rotations 

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. 
Decision Sheets 

December 2006 

Category 3. Is the substance compatible with organic production practices? Substance – Aqueous potassium 

silicate

Question Yes No N/A1 Documentation 

(TAP; 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 X 

No, the use of this synthetic material as a soil /plant amendment is not 

compatible with organic farming rules. 

Yes, the use of this material as plant disease control and as insecticide could 

be considered consistent with organic farming and could help replace some 

uses of other synthetics such as copper and sulfur. (TAP pg 6 & 8, item #7; 

Pg 8, item #6; pg 8 &12, Recommendations to NOSB) 

3. Is the substance compatible 

with a system of sustainable 

agriculture? [§6518 m.7] 

X 

TAP pg 6 & 8, item #7 

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 

b. toxins derived from bacteria; X 

c. pheromones, soaps, 

horticultural oils, fish emulsions, 

treated seed, vitamins and 

minerals? 

X 

It is a mineral – potassium and silica are minerals 

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. 
Decision Sheets 

December 2006 

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 - ______________________________________

Question Yes No N/A Comments on Information Provided (sufficient, 

plausible, reasonable, thorough, complete, unknown) 

1. Is the comparative description

provided as to why the non-organic 

form of the material /substance is 

necessary for use in organic handling? 

 

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? 

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? 

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 appropriate 

quantity to fulfill an essential 

function in a system of organic 

handling? 

5. Does the industry information 

provided on material / substance nonavailability as organic, include ( but 

not limited to) the following: 

a. Regions of production (including 

factors such as climate and number of 

regions); 

b. Number of suppliers and amount 

produced; 

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; 

d. Trade-related issues such as 

evidence of hoarding, war, trade 

barriers, or civil unrest that may 

temporarily restrict supplies; or 

e. Are there other issues which may 

present a challenge to a consistent 

supply? 
Decision Sheets 

December 2006