National Organic Standards Board

 Crops Subcommittee

Petitioned Material Proposal & Checklist - Exhaust Gas

December 16, 2014

Summary of Proposed Action:

Exhaust gas from internal combustion engines has been petitioned for use for control of burrowing 

rodents, under §205.601 Synthetic substances allowed for use in organic crop production. Exhaust gas 

contains carbon monoxide, which diminishes the oxygen-carrying capacity of red blood cells in the 

target rodents, and carbon dioxide, which displaces oxygen from the atmosphere of the burrow, leading

to asphyxiation of the rodent. The Crops Subcommittee did not support this petition because of 

concerns about potential impacts on non-target species, especially threatened and endangered species 

as well as potential effects on soil microorganisms. 

Background:

The original petition was for “Carbon Monoxide” and was sent to the NOP on 4/19/12. The Crops 

Subcommittee found the petition incomplete on 12 04 12 and asked the petitioner for additional 

information. The petitioner submitted a petition addendum on 2 22 13. The petition was determined 

sufficient by the Crops Subcommittee on 1 21 14. A technical review of exhaust gas for use as a

rodenticide was received October 2014.

In an April 2011 sunset review, sulfur dioxide for use as a rodenticide failed to be relisted by a vote of 9 

to 0 and was taken off the National List. In December 2011 a petition to add propane gas to the 

National List as a rodenticide was denied by a vote of 0 in favor and 14 opposed.

Evaluation Criteria (see attached checklist for criteria in each category)

 Criteria Satisfied? 

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 

Substance Fails Criteria Category: 1, 2, 3 

Subcommittee Action & Vote

Classification Motion: Move to classify Exhaust Gas as synthetic 

Motion by: Francis Thicke 

Seconded by: Harold Austin

Yes: 5 No: 0 Abstain: 0 Absent: 2 Recuse: 0 

Listing Motion: Move to list Exhaust Gas at §205.601 Synthetic substance allowed for use in 

organic crop production.

Motion by: Francis Thicke 

Seconded by: Harold Austin

Yes: 0 No: 5 Absent: 2 Abstain: 0 Recuse: 0 

Proposed Annotation (if any): none

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Approved by Zea Sonnabend, Subcommittee Chair, to transmit to NOSB December 16, 2014

NOSB Evaluation Criteria for Substances Added To the National List – Crops

Category 1. Adverse impacts on humans or the environment? Substance: Exhaust Gas

Question Yes No N/A Comments/Documentation (TAP; 

petition; regulatory agency; other)

1. Is there a probability of environmental 

contamination during use or misuse? 

[§6518(m)(3)]

X 

TR lines 299-302: “High volume releases 

of exhaust gases to the atmosphere are 

associated with a variety of adverse 

environmental impacts. Specifically, 

exhaust gas emissions contribute to air 

pollution, and four of its components 

(particulate matter, carbon monoxide, 

nitrogen oxides and sulfur dioxide) are 

criteria pollutants according to US EPA 

(2012. 

2. Is there a probability of environmental 

contamination during, manufacture or 

disposal? [§6518(m)(3)] X 

Exhaust gas is “manufactured” by the 

burning of fuel in internal combustion 

engines. As noted in #1 above, the 

manufacture of exhaust gas contributes 

to air pollution. 

3. Are there any adverse impacts on 

biodiversity? (§205.200)

X 

If other animals are present in the rodent 

burrows, they could also be affected: TR 

353-354: “Non-target animals may also 

dwell underground and be exposed to 

exhaust gas following its release in the 

treated area. Potentially affected nontarget animals include other mammals, 

birds, reptiles, amphibians, invertebrates 

(e.g., bumble bees and earthworms), 

slugs, snails, protozoa and nematodes.”

The TR (lines 354-355) states “Limited 

data is available regarding the effects of 

exhaust gas on soil organisms.”

4. Does the substance contain inerts 

classified by EPA as ‘inerts of 

toxicological concern’? [§6517 

(c)(1)(B)(ii)]

X 

5. Is there potential for detrimental chemical 

interaction with other materials used in 

organic farming systems?

[§6518(m)(1)] 

X 

TR lines 337-338: “no interactions 

between exhaust gas or its component 

chemicals and other common substances 

used in agriculture were identified.”

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6. Is there a toxic or other adverse action of 

the material or its breakdown products?

[§6518(m)(2)]

X 

The CO is toxic (as it is intended to be). 

Long-term inhalation of exhaust gas can 

be harmful to health (TR lines 259-269). 

When exhaust gas is injected into rodent 

burrows the exposure to humans would 

be minimal, but there would be exposure 

of toxic compounds to non-target 

organisms, as noted in #3 above.

7. Is there persistence or concentration of 

the material or breakdown products in 

the environment? [§6518(m)(2)]

X 

The exhaust gases that escape the 

rodent burrow after treatment disperse 

into the atmosphere where they are 

subject to many chemical transformations 

in the atmosphere (TR lines 219-254). TR 

lines 225-227: “CO2 can be long-lived in 

the atmosphere, with half-lives ranging 

from five to 200 years, depending on the 

model parameters (IPCC, 2001; Moore, 

1994).”

In the soil, CO can be converted to CO2 

by soil microorganisms (TR line 224). 

Information is not available on other 

possible reactions in the soil.

8. Would the use of the substance be 

harmful to human health or the 

environment? [§6517 (c)(1)(A)(i); §6517 

(c)(2)(A)(i); §6518(m)(4)]

X 

Similar to, or less than, being around 

standard vehicles with internal 

combustion engines.

9. Are there adverse biological and 

chemical interactions in the agroecosystem? [§6518(m)(5)]X 

TR lines 337-338: “no interactions 

between exhaust gas or its component 

chemicals and other common substances 

used in agriculture were identified.”

10. Are there detrimental physiological 

effects on soil organisms, crops, or 

livestock? [§6518(m)(5)]

X 

TR lines 352-355: “Non-target animals 

may also dwell underground and be 

exposed to exhaust gas following its 

release in the treated area. Potentially 

affected non-target animals include other 

mammals, birds, reptiles, amphibians, 

invertebrates (e.g., bumble bees and 

earthworms), slugs, snails, protozoa and 

nematodes. Limited data is available 

regarding the effects of exhaust gas on 

soil organisms.”

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NOSB Evaluation Criteria for Substances Added To the National List - Crops 

Category 2. Is the Substance Essential for Organic Production? Substance: Exhaust Gas

Question Yes No N/A Comments/Documentation (TAP; 

petition; regulatory agency; other)

1. Is the substance agricultural? [§6502(1)] X

2. Is the substance formulated or 

manufactured by a chemical process? 

[§6502(21)]

X 

It is “manufactured” by burning liquid fuel 

in an internal combustion engine.

3. 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 

4. Is the substance created by naturally 

occurring biological processes? 

[§6502(21)]

X 

5. Is there a natural source of the 

substance? [§ 205.600(b)(1)] X

6. Is there an organic substitute? 

[§205.600(b)(1)] X

7. Is there a wholly natural substitute 

product?

[§6517(c)(1)(A)(ii)]

X 

8. Are there any alternative substances? 

[§6518(m)(6)] 

X 

Vitamin D3 is on the National List 

§205.601(g). Vitamin D3 (cholecalciferol) 

produces hypercalcemia (i.e., excessive 

levels of calcium in the blood). Rodents 

generally die within two days following 

ingestion of a lethal dose (TR 473-474).

9. Are there other practices that would 

make the substance unnecessary? 

[§6518(m)(6)]

X 

Traps, barriers, natural predation, and 

other physical control methods can be 

used (TR lines 505-554).

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NOSB Evaluation Criteria for Substances Added To the National List - Crops 

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

Exhaust Gas

Question Yes No N/A Comments/Documentation (TAP; 

petition; regulatory agency; other)

1. Is the substance consistent with organic 

farming and handling? 

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

X 

Internal combustion engines are used in 

organic farming. However, injecting 

exhaust gases into the soil profile is not a 

standard kind of practice in organic 

farming.

2. Is the substance compatible with a 

system of sustainable agriculture? 

[§6518(m)(7)] 

X 

Internal combustion engines are used in 

sustainable farming systems. However, 

injecting exhaust gases into the soil 

profile might be considered contrary to 

sustainable agriculture

3. If used in livestock feed or pet food, Is 

the nutritional quality of the food 

maintained with the substance? 

[§205.600(b)(3)]

X 

4. If used in livestock feed or pet food, Is 

the primary use as a preservative? 

[§205.600(b)(4)]

X 

5. If used in livestock feed or pet food, Is 

the primary use to recreate or improve 

flavors, colors, textures, or nutritive value 

lost in processing (except when required 

by law)? [§205.600(b)(4)]

X 

6. 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

X 

There can be small amounts of sulfur 

compounds in exhaust gas, but they are 

not active ingredients.

toxins derived from bacteria X

pheromones, soaps, horticultural oils, 

fish emulsions, treated seed, vitamins 

and minerals

X 

livestock parasiticides and medicines X

production aids including netting, tree 

wraps and seals, insect traps, sticky 

barriers, row covers, and equipment 

cleansers

X 

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