Page 2 of 6

Subsequent to completion of the human health risk assessment entitled Dimethomorph: Human 

Health Risk Assessment to Support Amended Use on Grapes, Bulb Vegetables, Leafy Brassica 

Vegetables, and Leafy Vegetables (D387381, 09/15/11), Health Canada’s Pest Management 

Regulatory Agency (PMRA) informed HED that they had an expansion of the same uses for 

dimethomorph. HED agreed to harmonize with PMRA in/on bulb vegetables (CG3), leafy 

vegetable except Brassica (CG 4), Brassica vegetables (CG5) and grapes tolerances. Also, the 

registrant, BASF Corporation requested further clarification/ explanation on the requirement for 

crop restrictions in cereal crops and a 7-month rotational crop restriction for soybeans. 

Conclusions stated here supersede conclusions from the 09/15/11 memorandum.

In order to harmonize MRLs with Canada, Isabelle Piolet of PMRA provided input to the 

Agency in the form of written correspondence dated October 24, 2011 to Tamue Gibson, EPA. 

The residue values were entered into the OECD calculator to determine appropriate tolerance 

levels. The revised harmonized tolerances are shown in Table A.1. Additionally, a revised 

dietary assessment was conducted which included the harmonized tolerances. 

BASF Corporation’s request for clarification was provided to the Agency in the form of written 

correspondences dated November 4, 2011 and December 23, 2011 from Charlotte Sansom, Team 

Leader, to Tamue Gibson, EPA. The Agency reviewed BASF’s request with respect to residue 

chemistry data issues and has updated the previously generated residue chemistry chapters 

(D381813, S.Piper, 9/13/11). In summary, the Agency concluded that provided the registrant is 

willing to amend the proposed label to specify a 30-day PBI for cereal grains, then, tolerances 

are needed in rotated cereal grain commodities (forage, hay and straw) and recommended that 

the following tolerances be established:

Wheat, forage......................................................0.15 ppm

Wheat, hay .........................................................0.15 ppm

Wheat, straw .........................................................0.4 ppm

EPA's Chemistry Science Advisory Council (ChemSAC) met on February 29, 2012 to discuss 

BASF requests that EPA reduce the 7-month PBI to 1-month for soybeans and other legume 

vegetables and/or establish tolerances for inadvertent residues of dimethomorph in 

soybean/legume forage, straw, and seed similar to wheat, based on the following experimental 

observations and results from the confined rotational crop, field accumulation studies, and RAC 

studies for lima beans. ChemSAC recommended that the label remain at a 7 month plant back 

restriction for soybean other legume vegetables. To support a proposed 30-day plantback 

restriction on the label, limited field rotational crop data for soybean are required (D398565, S. 

Piper, 3/6/12).
Page 3 of 6

Updated Regulatory Recommendation

Provided the registrant submits a revised Section F (see Table 1), there are no human health risks 

of concern that would preclude the establishment or revision of tolerances for the residue of 

dimethomorph under 40 CFR 180.493 as follows:

Grape.....................................................................3.0 ppm

Grape, raisin..........................................................7.0 ppm

Brassica, head and stem, subgroup 5A ................6.0 ppm

Brassica, leafy greens, subgroup 5B...................30.0 ppm

Leafy Vegetable except Brassica, group 4.. .......30.0 ppm

Onion, bulb subgroup 3-07A ................................0.6 ppm

Onion, green subgroup 3-07B ...........................15.0 ppm

Under 40 CFR 180.493(d) for indirect or inadvertent residues of dimethomorph:

Wheat, forage......................................................0.15 ppm

Wheat, hay .........................................................0.15 ppm

Wheat, straw .........................................................0.4 ppm

Label Recommendations

Section B of the labels should be modified to specify a 30-day plant-back restriction for cereal 

grains, and a 7 month plant-back restriction for soybean and other legume vegetables; all other 

crops can be planted 12 months after the last application.

Chronic Dietary Risk Assessment

An acute endpoint was not selected for dimethomorph; therefore, the Agency conducted only a 

chronic dietary (food and drinking water) exposure and risk assessment. Based on the revised 

tolerances and assumed 100% crop treated, the chronic dietary risks are not of concern for the 

U.S. population and all subpopulations. For food and drinking water, the chronic aggregate 

dietary risk was calculated at 17% of the cPAD (chronic population adjusted dose). The 

exposure estimate for the most highly exposed subpopulation (children 1-2 years) is 27% of the 

cPAD. See Table 1.
Page 4 of 6

Table 1. Summary of Dietary Exposure and Risk for Dimethomorph

Population Subgroup

Acute Dietary Chronic Dietary Cancer

Dietary 

Exposure 

(mg/kg/day)

% 

aPAD

Dietary 

Exposure

(mg/kg/day)

% cPAD

Dietary 

Exposure

(mg/kg/day)

Ris

k

General U.S. Population

N/A

0.016520 17%

N/A

All Infants (< 1 year old) 0.012239 12%

Children 1-2 years old 0.026850 27%

Children 3-5 years old 0.023110 23%

Children 6-12 years old 0.015989 16%

Youth 13-19 years old 0.012770 13%

Adults 20-49 years old 0.016295 16%

Adults 50+ years old 0.016350 16%

Females 13-49 years old 0.016042 16%

The population with the highest exposure is in bold.

References

DP#: D398565

Subject: Addendum to Dimethomorph. Application for Proposed Amended Use on Grapes 

(PP#0F7751) and the Section 3 Registration Action on the Bulb Vegetables 

(PP#0F7800), Leafy Brassica Vegetables (PP#0F7800); and Leafy Vegetables 

(PP#0F7816). Summary of Analytical Chemistry and Residue Data.

From: S.Piper

To: T. Gibson, M. Waller

Date: 2/07/12

MRIDs: 47700109, 47700113, 47700114, 47700115, 47700105
Page 5 of 6

Appendix A. Proposed MRLs for Dimethomorph Residues in Plant Commodities

TABLE A.1. Proposed MRLs for Dimethomorph Residues in Plant Commodities

Crop 

Group

Representative 

Crops Formulation/ Use Pattern

Maximum 

Residues

(ppm)

Individual 

OECD 

Calculator 

MRL

(ppm)

Previously 

Proposed US

MRL

New Proposed

US and 

Canadian 

MRL

Crop 

Group 3

Dry bulb onion

WP (1.6 kg a.i./ha without 

adjuvant, 0d PHI) 0.28 0.5 0.6 ppm

for all crops of 

crop subgroup 

3-07A

0.6 ppm 

for all crops of 

CG 3-07A

SC (0.7 kg a.i./ha with 

adjuvant, 0d PHI) 0.40 0.6

Green onion

WP (1.6 kg a.i./ha without 

adjuvant, 0d PHI) 1.22 3

15 ppm

for all crops of 

crop subgroup 

3-07B

15 ppm 

for all crops of 

CG 3-07B

SC (0.7 kg a.i./ha with 

adjuvant, 0d PHI) 6.60 15

Crop 

Group 4

Leaf lettuce

WP (1.6 kg a.i./ha without 

adjuvant, 0d PHI) 9.10 20

20 ppm 

for all crops of 

crop group 4A

30 ppm 

for all crops of 

CG 4

SC (0.7 kg a.i./ha with 

adjuvant, 0d PHI) 10.53 20

Head lettuce

WP (1.6 kg a.i./ha without 

adjuvant, 0d PHI) 6.50 15

SC (0.7 kg a.i./ha with 

adjuvant, 0d PHI) 4.10 7

Spinach

WP (1.6 kg a.i./ha without 

adjuvant, 7d PHI) 10.10

Summary table 

only provided 

and raw data of 

poor quality; 

Use cannot be 

supported 15 ppm for 

leaf petioles4B

SC (0.7 kg a.i./ha with 

adjuvant, 0d PHI) 11.47 30

Celery

WP - No data --

Use cannot be 

supported

SC (0.7 kg a.i./ha with 

adjuvant, 0d PHI) 8.82 15

Crop 

Group 5

Cabbage

WP (1.6 kg a.i./ha without 

adjuvant, 7d PHI) 0.69 1.5

5.0 ppm

for all crops of 

crop subgroup 

5A

6.0 ppm

for all crops 

subgroup 5A

SC (0.7 kg a.i./ha with 

adjuvant, 0d PHI) 4.61 6

Broccoli

WP (1.6 kg a.i./ha without 

adjuvant, 7d PHI) 0.52 0.9

SC (0.7 kg a.i./ha with 

adjuvant, 0d PHI)

2.62 (1d 

PHI) 4

Mustard Green

WP - No data --

Use cannot be 

supported 30 ppm

for all crops of 

crop subgroup 

5B

30 ppm

for all crops of 

5B

SC (0.7 kg a.i./ha with 

adjuvant, 0d PHI) 19.25 30

SC (0.7 kg a.i./ha with 

adjuvant, 4d PHI) 0.42 0.6
Page 6 of 6

TABLE A.1. Proposed MRLs for Dimethomorph Residues in Plant Commodities

Crop 

Group

Representative 

Crops Formulation/ Use Pattern

Maximum 

Residues

(ppm)

Individual 

OECD 

Calculator 

MRL

(ppm)

Previously 

Proposed US

MRL

New Proposed

US and 

Canadian 

MRL

Grape

SC - dilute spray (0.9 kg 

a.i./ha with adjuvant, 14d 

PHI)

1.86 3

4.0 ppm 

for all crops of 

crop subgroup 

13-07F

(already registered 

on the Acrobat 

WP at a rate of 0.9 

kg a.i./ha and a 7d 

PHI, MRL of 1.5 

ppm)

3.0 ppm 

for grapes

SC – concentrated spray 

(0.9 kg a.i./ha with 

adjuvant, 14d PHI)

1.83 3

Raisin SC (0.9 kg a.i./ha with 

adjuvant, 14d PHI)

HAFT x PF = 1.86 x 3.8 

= 7.068 ppm 6.0 ppm for 

raisins 

7 ppm 

for raisins

Inadvertent Tolerances (for rotational crops)

Wheat, forage

WP (1.4 lb a.i., 23-52d 

PHI) 0.06 0.15 -- 0.15 ppm for 

SC (0.68 kg a.i./ha with wheat forage

adjuvant, 30- 120d PHI) 0.03 0.06 --

Wheat, hay

WP (1.4 lb a.i., 23-52d 

PHI) <0.05 0.15 -- 0.15 ppm for 

SC (0.68 kg a.i./ha with wheat hay

adjuvant, 30- 120d PHI) 0.05 0.15 --

Wheat, straw

WP (1.4 lb a.i., 23-52d 

PHI) 0.07 0.15 -- 0.4 ppm for 

SC (0.68 kg a.i./ha with wheat straw

adjuvant, 30- 120d PHI) 0.20 0.4 --