COMPANY FEDERAL REGISTER DOCUMENT SUBMISSION 

EPA Registration Division contact: Bethany Benbow (703) 347-8072

BASF Corporation

Petition# 0E7781

EPA has received a pesticide petition (0E7781) from BASF Corporation, P.O. Box 

13528, Research Triangle Park , NC 27709 proposing, pursuant to section 408(d) of the 

Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR part 

180.560 by amending the tolerance expression to establish combined residues of

cloquintocet-mexyl (acetic acid, [(5-chloro-8-quniolinyl)oxy]-, 1-methylhexylester)(CAS Reg.

No. 99607-70-2) and its acid metabolite (5-chloro-8-quinlinoxyacetic acid) when used as an 

inert ingredient (safener) in pesticide formulations containing either the herbicide 

clodinafop-propargyl or pinoxaden in a 1:4 ratio of safener to active ingredient or in 

combination with the registered active ingredient dicamba in or on the following established 

raw agricultural commodities: wheat, grain at 0.10 parts per million (ppm), wheat, forage at

0.2 ppm, wheat, hay at 0.50 ppm, and wheat, straw at 0.10 ppm. EPA has determined that the 

petition contains data or information regarding the elements set forth in section 408(d)(2) of the 

FFDCA; however, EPA has not fully evaluated the sufficiency of the submitted data at this time 

or whether the data supports granting of the petition. Additional data may be needed before 

EPA rules on the petition.

A. Residue Chemistry 

1. Plant metabolism. The metabolism of cloquintocet-mexyl in wheat is well 

understood, as was published previously in the Federal Register (April 19, 2000, Volume 65, 

Number 76, page 20972 - 20976). Total residues in all crop samples are low. Metabolism 

involves primarily rapid hydrolysis of the parent to the resulting acid followed by 

conjugation.

2. Analytical method. A practical analytical method for the determination of 

cloquintocet-mexyl and its major plant metabolite CGA-153433 in wheat RACs has 

previously been published in the Federal Register (April 19, 2000, (Volume 65, Number 76), 

page 20972 - 20976). 

3. Magnitude of residues. The magnitude of residue of cloquintocet-mexyl was 

published previously in the Federal Register (April 19, 2000, (Volume 65, Number 76), page 

20972 - 20976).
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B. Toxicological Profile

1. Acute toxicity. Cloquintocet-mexyl has a low order of acute toxicity. The acute 

toxicity profile of cloquintocet-mexyl was published previously in the Federal Register 

(April 19, 2000, (Volume 65, Number 76), page 20972 - 20976). The EPA has published 

the acute toxicity endpoints in the Federal Register (June 22, 2000 (Volume 65, Number 

121), page 38757-38764).

2. Genotoxicty. Cloquntocet-mexyl was negative in all genotoxicity tests. The 

genotoxicity of cloquintocet-mexyl was published previously in the Federal Register (April 

19, 2000, (Volume 65, Number 76), page 20972 - 20976).

3. Reproductive and developmental toxicity. Cloquintocet-mexyl is not a reproductive 

or developmental toxicant. The toxicity of cloquintocet-mexyl was published previously in 

the Federal Register (April 19, 2000, (Volume 65, Number 76), page 20972 - 20976). The 

EPA has published the reproductive and developmental toxicity endpoints in the Federal 

Register (June 22, 2000 (Volume 65, Number 121), page 38757-38764).

4. Subchronic toxicity. The subchronic toxicity profile of cloquintocet-mexyl was 

published previously in the Federal Register (April 19, 2000, (Volume 65, Number 76), page 

20972 - 20976). The EPA has previously published the subchronic toxicity endpoints in 

the Federal Register (June 22, 2000 (Volume 65, Number 121), page 38757-38764).

5. Chronic toxicity. The chronic toxicity profile of cloquintocet-mexyl was published 

previously in the Federal Register (April 19, 2000, (Volume 65, Number 76), page 

20972 - 20976). The EPA has published the chronic toxicity endpoints in the Federal 

Register (June 22, 2000 (Volume 65, Number 121), page 38757-38764). The Agency 

classified cloquintocet-mexyl as``not likely to be a human carcinogen''.

6. Animal metabolism. The metabolism of cloquintocet-mexyl in animals is well 

understood, as was published previously in the Federal Register (April 19, 2000, (Volume 

65, Number 76), page 20972 - 20976). In rats, approximately 50% of an oral dose of 

cloquintocet-mexyl was rapidly absorbed through the gastrointestinal tract and excreted 

via urine and bile. The administered dose was excreted independent of sex and was 

essentially complete within 48 hours. Ninety-five percent of the excreted dose was 

associated with one metabolite, the acid residue of cloquintocet-mexyl 

(5-chloro-8-quinlinoxyacetic acid, CGA-153433).

7. Metabolite toxicology. The main metabolite in both plants and animals is 

5-chloro-8-quinlinoxyacetic acid. As this is the main metabolite in rats, rabbits and mice, its 

toxicology has been tested throughout the toxicology database for cloquintocet-mexyl. The 

toxicity of cloquintocet-mexyl metabolites was discussed previously in the Federal Register 
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(April 19, 2000, (Volume 65, Number 76), page 20972 - 20976).

8. Endocrine disruption. There is no evidence that cloquintocet-mexyl has any effect 

on endocrine function, as was discussed previously in the Federal Register (April 19, 2000, 

(Volume 65, Number 76), page 20972 - 20976).

C. Aggregate Exposure

1. Dietary exposure. BASF is not proposing any new tolerances or modifications to 

existing tolerances for cloquintocet-mexyl. Therefore, the most recent EPA human health 

assessment for cloquintocet-mexyl, “Human Health Risk Assessment for 

Cloquintocet-mexyl for uses on Wheat and Barley” November 29, 2005, is applicable to the 

current notification. The US EPA has determined that an acute dietary assessment is only 

required for females ages 13-49. A suitable acute endpoint for the general population was 

not identified because there were no effects observed in the oral toxicity studies 

attributable to a single dose exposure. The acute population adjusted does for females is 

1.0 mg/kg bw-day (NOAEL = 100 mg/kg bw-day, safety factor = 100. The chronic 

population adjusted does determined by the US EPA is 0.04 mg/kg bw-day (NOAEL = 4.3 

mg/kg bw-day, safety factor = 100).

i. Food. The acute dietary assessment for cloquintocet-mexyl is a Tier 1 

assessment because no data was used to refine the exposure estimate. The 

exposure estimate was determined using 100% crop treatment factors and 

tolerance level reidues for all commodities. The highest estimated acute 

drinking water estimated, 0.186 ppb, was included in the dietary assessment 

conducted by EPA. The acute assessment is shown in Table 1. 

Table 1. Summary of Acute Dietary Exposure Assessment 

(food + water) Considering All Crops with Established and Proposed 

Tolerances for Cloquintocet-mexyl.

Population

Subgroups

Exposure Estimate

(mg/kg b.w./day) %aPAD

Females 13 - 49 0.000347 < 1

%cPAD = percent of chronic population adjusted dose 

Exposure estimates based on tolerance values, default processing 

factors, and 100% CT for all crops/commodities
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The chronic dietary assessment for cloquintocet-mexyl is a Tier 1 assessment 

because no data was used to refine the exposure estimate. The exposure estimate 

was determined using 100% crop treatment factors and tolerance level reidues for 

all commodities. The highest estimated acute drinking water estimated, 0.005 ppb, 

was included in the dietary assessment conducted by EPA. The chronic assessment 

is shown in Table 2

Table 2. Summary of Chronic Dietary Exposure Assessment (Food + 

drinking water) Considering All Crops with Established and Proposed 

Tolerances for Cloquintocet-mexyl

Population

Subgroups

Exposure Estimate

(mg/kg b.w./day) %cPAD

U.S. Population 0.000180 < 1

All Infants 0.000077 < 1

Children 1-2 years 0.000403 < 1

Children 3-5 years 0.000411 < 1

Children 6-12 years 0.000289 < 1

Youth 13-19 years 0.000176 < 1

Adults 20-49 years 0.000153 < 1

Adults 50+ years 0.000120 < 1

Females 13 - 49 0.000137 < 1

%cPAD = percent of chronic population adjusted dose 

Exposure estimates based on tolerance values, default processing 

factors, and 100% CT for all crops/commodities

The results in Table 1 and 2 demonstrate there are no safety concerns for any 

subpopulation based on established and new uses, and the results clearly meet the 

FQPA standard of reasonable certainty of no harm.

ii. Drinking water. The US EPA Environmental Fact and Effects Division (EFED) 

has determined the higest EECs for the acute and chronic exposures. The acute EEC is 

0.186 ppb and the chronic EEC is 0.005 ppb. These water EEC values were included in 

the dietary assessments referenced above. 

2. Non-dietary exposure. Products containing the safener cloquintocet-mexyl will be 

registered for agricultural uses only and will not be available for any residential or public 

uses. Therefore, the aggregate risk is the sum of the risk from food and water.
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D. Cumulative Effects

Cumulative Exposure to Substances With a Common Mechanism of Toxicity. 

Section 408(b)(2)(D)(v) requires that, when considering whether to establish, modify, or 

revoke a tolerance, the Agency consider "available information" concerning the cumulative 

effects of a particular pesticide's residues and "other substances that have a common 

mechanism of toxicity". A discussion of the availability of data for determination whether 

cloquintocet-mexyl has a common mechanism of toxicity with other substances was 

included in the Federal Register Tolerance Notice of June 22, 2000 (Volume 65, Number 

121, page 38757-38764)

E. Safety Determination

1. U.S. population. BASF has considered the potential aggregate exposure from food, 

and water exposure routes and concluded that aggregate exposure is not expected to exceed 

100% of the chronic or acute reference dose and that there is a reasonable certainty that no 

harm will result to infants and children from the aggregate exposure to cloquintocet-mexyl.

2. Infants and children. BASF has considered the potential aggregate exposure from 

food, and water exposure routes and concluded that aggregate exposure is not expected to 

exceed 100% of the chronic or acute reference dose and that there is a reasonable certainty 

that no harm will result to infants and children from the aggregate exposure to 

cloquintocet-mexyl.

F. International Tolerances

There are no international tolerances for the inert (safener), cloquinocet-mexyl