UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION

MEMORANDUM

Date: May 18, 2011

SUBJECT: 2,4-D: Petition for the Establishment of Tolerances on Teff; Request for Registration of 

Latigo (EPA Reg No. 5905-564) on Teff. Consideration of Changes in Percent Crop 

Treated.

PC Codes: 030001 DP Barcode: 389865

Decision No.: 440785 Registration No.: 5905-564

Petition No.: 0E7796 Regulatory Action: Section 3 Registration

Risk Assessment Type: Human Health Risk 

Assessment

Case No.: NA

TXR No.: NA CAS No.: 94-75-7

MRID No.: NA 40 CFR: §180.142

 

 

FROM: Christine Olinger, Risk Assessor

Risk Assessment Branch VII

Health Effects Division (7509P)

THROUGH: Michael Metzger, Branch Chief

Risk Assessment Branch VII

Health Effects Division (7509P)

TO: Laura Nollen

RIMUERB, Registration Division (7505P)

This document provides an assessment of potential change in aggregate risk as a result of changes in the 

2,4-D percent crop treated since the last comprehensive risk assessment (Timothy C. Dole, 5/12/05). 

This assessment is being done to support the subject use of 2,4-D on teff. 

The Chronic dietary assessment will be used to screen for potential increase in dietary risk. While this 

approach does not directly address acute risk, the major commodities likely to contribute to acute risk are 

single serving commodities such as pome, citrus, and stone fruit, which have mostly non-detectable 

residues (higher residues are generally found in field crops). Furthermore, the changes in PCT observed 

are minor. Also, changes in PCT will not affect residential or occupational risk estimates. 

HED has completed a screening level assessment of the change in chronic risk as follows:
1. Complete a Commodity Contribution Analysis based on the last comprehensive risk assessment 

using a threshold for results presentation of > 0.1% cPAD. 

2. For commodities < 0.1 % cPAD, assume 0.1% cPAD commodity contribution

3. Multiply the commodity contribution (% cPAD) for each commodity by the factor by which the 

PCT has changed.

4. Sum the total risk

The results are shown in the attached table. The changes in risk from the 2005 assessment to 2011 for the 

general population and children (the most sensitive subpopulation) are 2.2% and 3.1% cPAD, 

respectively. These differences are insignificant. Therefore, HED concludes that changes in PCT 

between the 2005 risk assessment and 2011 will not result in significant changes in estimated aggregate 

risk. 

It should be noted that many conservative assumptions were incorporated into this screening level 

assessment to minimize unnecessary use of resources, and these estimates of changes in risk as a result of 

changes in PCT are therefore very conservative.

Changes in 2,4-D Chronic Risk Estimates Resulting From Changes in Percent Crop Treated 

Between 2005 and 2011.

Crop

% Crop Treated

Commodity Contribution 

(2005)

Commodity 

Contribution (2011)

New Old

Proportional 

Change

%cPAD, 

Gen pop

%cPAD, 

Children 1-6

%cPAD, 

Gen pop

%cPAD, 

Children 1-

6

Alfalfa <1 0.6 1.00 0.1 0.1 0.10 0.10

Almonds 15 10 1.50 0.1 0.1 0.15 0.15

Apples 20 36 0.56 0.1 0.1 0.10 0.06

Apricots 15 8 1.88 0.1 0.1 0.19 0.19

Asparagus 10 15 0.67 1.2 0.98 0.80 0.65

Avocados 1 NA 1.00 0.1 0.1 0.10 0.10

Barley 30 43 0.70 0.1 0.1 0.10 0.07

Beans, green <1 3 0.30 0.1 0.1 0.10 0.03

Blueberries <1 0.5 1.00 0.1 0.1 0.10 0.10

Cane berries <2.5 NA 1.00 0.1 0.1 0.10 0.10

Canola/rapeseed <2.5 2 1.00 0.1 0.1 0.10 0.10

Cherries 15 24 0.63 0.1 0.1 0.10 0.06

Corn 5 12 0.42 1.9 4.15 0.79 1.73

Cotton 5 3 1.67 0.1 0.1 0.17 0.17

Cucumbers <1 NA 1.00 0.1 0.1 0.10 0.10

Dry beans/peas <1 NA 1.00 0.1 0.1 0.10 0.10

Fallow, summer 20 10 2.00 0.1 0.1 0.20 0.20

Grapefruit 15 19 0.79 0.1 0.02 0.10 0.02

Grapes 5 2 2.50 0.1 0.1 0.25 0.25

Hazelnuts 

(filberts)

55 58

0.95 0.1 0.1 0.10 0.09
Crop

% Crop Treated

Commodity Contribution 

(2005)

Commodity 

Contribution (2011)

New Old

Proportional 

Change

%cPAD, 

Gen pop

%cPAD, 

Children 1-6

%cPAD, 

Gen pop

%cPAD, 

Children 1-

6

Lemons <2.5 1.5 1.00 0.1 0.1 0.10 0.10

Nectarines 15 10 1.50 0.1 0.1 0.15 0.15

Oats 15 19 0.79 0.1 0.11 0.10 0.09

Onions 5 NA 1.00 0.1 0.1 0.10 0.10

Oranges 15 7 2.14 0.25 0.49 0.54 1.05

Pastures 10 5 2.00 0.1 0.1 0.20 0.20

Peaches 15 12 1.25 0.1 0.1 0.13 0.13

Peanuts 5 4 1.25 0.1 0.1 0.13 0.13

Pears 15 14 1.07 0.1 0.1 0.11 0.11

Peas, green <1 NA 1.00 0.1 0.1 0.10 0.10

Pecans 5 NA 1.00 0.1 0.1 0.10 0.10

Pistachios 5 NA 1.00 0.1 0.1 0.10 0.10

Plums 20 17 1.18 0.1 0.1 0.12 0.12

Potatoes <1 2 2.00 0.71 1.41 1.42 2.82

Prunes 15 NA 1.00 0.1 0.1 0.10 0.10

Pumpkins <1 NA 1.00 0.1 0.1 0.10 0.10

Rice 10 17 0.59 2.85 5.3 1.68 3.12

Sorghum 20 16 1.25 0.1 0.1 0.13 0.13

Soybeans 5 7 0.71 0.1 0.1 0.10 0.07

Squash <2.5 NA 1.00 0.1 0.1 0.10 0.10

Strawberries 5 7 0.71 0.1 0.1 0.10 0.07

Sugarbeets <1 NA 1.00 0.1 0.1 0.10 0.10

Sugarcane 40 53 0.75 0.1 0.08 0.10 0.06

Sunflowers 5 4 1.25 0.1 0.1 0.13 0.13

Sweet corn 5 NA 1.00 0.19 0.49 0.19 0.49

Tangelos 15 NA 1.00 0.1 0.1 0.10 0.10

Tangerines 5 NA 1.00 0.1 0.03 0.10 0.03

Tobacco <1 NA 1.00 0.1 0.1 0.10 0.10

Tomatoes <2.5 NA 1.00 0.1 0.1 0.10 0.10

Walnuts 10 9 1.11 0.1 0.1 0.11 0.11

Watermelons <1 NA 1.00 0.1 0.1 0.10 0.10

Wheat 25 4 (Spring 

) 6.00 0.1 0.16 0.60 0.96

24 

(Winter) 1.00 0.1 0 0.10 0.00

Meat / fish / Milk 2.00 2.65 4.83 5.30 9.66

Total---> 14.45 22.15 16.65 25.27