OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 

RE: Meeting between Dow AgroSciences (DAS) and EPA to Discuss Risk Concerns 

Related to Occupational Exposures

List of Documents

1. Meeting Summary Page 1 

2. Meeting Sign in Sheet Page 2 

3. DAS PowerPoint Presentations Page 3 

Meeting Summary 

On Thursday, April 2, 2015, EPA met with DAS, one of the chlorpyrifos technical registrants. 

The chlorpyrifos revised human health risk assessment (RHHRA) released in January 2015 

identified a number of use scenarios that showed risk concerns to workers. This meeting initiated 

discussion on ways to mitigate risk concerns to workers. Discussions will continue with DAS 

and the other technical registrants. 

EPA REVISED OCCUPATIONAL ASSESSMENT IN THE 

REVISED HUMAN HEALTH ASSESSMENT FOR 

CHLORPYRIFOS

Joe Velovitch, 

Senior Risk Assessor, 

Dow AgroSciences LLC

April 2nd, 2015
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1. Key EPA Assumptions for Occupational Risk Assessment

2. Examples of Deconstructed Scenarios

3. Refinement/Mitigation Opportunity

Occupational RA Methodology Review
| 3

• MOE = 100 based on

 FQPA SF (2014) raised from 1X to 10X

 Intraspecies UF of 10X (for period during pregnancy)

• Lower PoD used in calculation

• Traditionally, HED typically classifies exposures from 1 to 30 days as 

short-term and exposures 30 days to six months as intermediate-term, 

 for this RA the steady state endpoint (21-d ) selection was used for chlorpyrifos which 

overlaps HED’s traditional short-term exposure duration endpoint selection and is 

considered health protective for both short- and intermediate- term exposures

EPA’s Assumptions for Occupational RA in the Revised 

Human Health Assessment
| 4

• DAS Effort: Complete deconstruction of the occupational risk 

components in the Revised HH Assessment for all uses

 Assessments and deconstruction to individual crop and application 

scenario level was complex

• DAS Goal: Full understanding of all chlorpyrifos crop and non-crop use 

occupational scenarios to determine options for refinement of 

assessments and consideration of mitigation options

DAS Review of Occupational RA
| 5

 The deconstruction analysis: 

1) summarized the EPA summary (placed into Excel)

2) unbundled crop groupings used by EPA, to crop by crop

3) separated each unbundled crop by Mixer/Loaders, Applicators, 

Mixer/Loader/Applicators / (Flaggers) evaluated

• How we did the analysis: 

 Contracted with Exponent, Inc, as consultant to the project

 Exponent deconstructed actual EPA Revised HH RA and Occupational and 

Residential Handler RA groupings for combinations of similar use patterns (crop, 

rate, application scenario) 

DAS Occupational Exposure Assumptions
| 6

Occupational: What we did – example

*Chlorpyrifos: Updated Occupational and Residential Exposure Assessment for

Registration Review. D424484. December 29, 2014

Mixer/

Loader+

Mixing/

Loading

Liquids 

for

Groundboom

Applicati

on

(1c)

App. M/L paired with App.
| 7

Occupational: What we did – example

1c AA-DAS

Mixing/Loading Liquids 

for Ground-Boom 

Application

*Tree nut orchard floors 

(almonds, walnuts): App rate 

4.0 lb ai/A and 80 Acres 

treated passes with EC

None passed in EPA 

revised assessment

7a A-DAS Ground-Boom 

Applications

*Tree nut orchard floors 

(almonds, walnuts): App rate 

of 4.0 lb ai/A and 80 Acres 

treated passes at SL/G PF5 R, 

SL/G PF10 R, and DL/G PF10 

R

*Tree nut orchard 

floors (almonds, 

walnuts): App rate of 

4.0 lb ai/A and 80 

Acres treated passes 

with EC

1) Converted: Table F.1. Chlorpyrifos Occupational Handler Non-Cancer Risk Estimates 

from HH RA to Excel, then,

2) Grouped M/L with Applicator for same EPA grouped crops...allowing transparency to 

determine which scenario met an MOE of 100 (in this example, 1c vs 7a)

Mixer/

Loader

App.

+
| 8

• Next, we wanted to understand RA [specific] crop x [specific] crop, against each

Exposure Scenario that EPA evaluated in the Revised HH Assessment.....

• Unbundled the

 crop group

 output:

• This allows crop

by crop analysis

Occupational: What we did – example

EPA 

Exposure 

Scenario

Registrant Commodity MOE of 100

1c AA-DAS

Mixing/Loading Liquids for 

Ground-Boom Application Almond None passed

7a A-DAS Ground-Boom Applications Almond

*Tree nut orchard floors (almonds, 

walnuts): App rate of 4.0 lb ai/A and 80 

Acres treated passes with EC

1c AA-DAS

Mixing/Loading Liquids for 

Ground-Boom Application Walnuts None passed

7a A-DAS Ground-Boom Applications Walnuts

*Tree nut orchard floors (almonds, 

walnuts): App rate of 4.0 lb ai/A and 80 

Acres treated passes with EC
| 9

• EPA assumes a 3 week exposure period (5 weekday exposed, 2 

weekend days off)

• Dow AgroSciences has surveyed growers and commercial 

applicators that use soybeans, wheat, corn, stone and pome 

fruit, tree nuts, citrus

─ Typical case: 1-2 days of consecutive exposure

─ Infrequent case: >5 days for commercial applicators, >2-3 days for 

growers

 Commercial applicators more frequently use engineering controls 

and use more PPE

Occupational Risk Refinement Example
| 10

• Request contact at HED to work with and confirm acceptability of 

proposed refinements criteria (what) and options (how)

• What specific points and information should DAS ensure are included in 

official response on the methodology and in what form?

• Any other suggestions are welcome!

Further Action Plans
Questions / Discussion
Discussion of Occupational Risk Assessment in the 

Revised Risk Assessment for Chlorpyrifos

George Oliver, Regulatory Leader, Dow AgroSciences, Indianapolis, IN

April 2, 2015
| 2

• George Oliver, Regulatory Leader for chlorpyrifos, Dow AgroSciences

• Joe Velovitch, Human Health Assessment, Dow AgroSciences

• Daland Juberg, Global Leader, Human Health Assessment, Dow AgroSciences

• Rick Reiss, Interim Group Vice President (Health) and Principal Scientist, 

Exponent, Inc

Introductions
| 3

1. Share DAS methodology and results of analysis to individual crop use 

scenario level of EPA’s Occupational Risk Assessment from the 

Revised Human Health Assessment

2. Identify next steps

─ Further discussions on uses and refinement options

─ How best to submit the information to EPA

Overall objectives for today

Information presented represents a work in progress and should be 

considered preliminary information
| 4

• Introduction and overview (G Oliver)

• Dow AgroSciences (DAS) approach and methodology for analysis of 

EPA’s occupational assessment. (J Velovitch)

 Focus on mixer/loader and applicator for crop and non-crop uses

• Initial results of breakdown of use scenarios (G Oliver)

• Discussion

Agenda for today
| 5

• Preliminary Assessment was in 2011

• Revised Assessment:

 Released Dec 31, 2014

 Docket opened and start of comment period Jan 14, 2015

 Comment period extension to April 30, 2015

• Revised Assessment:

 Complex (approx. 1000) pages

 New approaches

 New values for PoD, Uncertainty Factors (UF) and Safety Factors (SF)

 Complex analysis to reach individual crop use scenario

Background: The Revised Human Health Assessment
Part 2 of today’s discussion

Building from Part 1
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• Objectives

• Background

• Example of listing of crop use scenarios – foundation for grouping into 

categories

• Definition of use scenarios groupings

• Approximate breakdown of use scenarios by groupings

• Questions / discussion / next steps

Agenda for 2nd part of today’s meeting
| 8

• Sharing of groupings of use scenarios built from our analysis of EPA occupational 

assessment in the Revised Human Health Assessment

• Discussion of next steps for working cooperatively for refinement and addressing 

remaining issues

• Feedback on best format for submitting extensive data tables – both base presentation of 

individual use scenarios and background supporting data

Objectives for today’s meeting – part 2
| 9

EPA scenario 

code

Application activity 

description Crop Application rate (lbs ai / A) Acres treated Results for MOE of 100

3b

Mixing/Loading Granulars for 

Tractor Drawn Spreader 

Applications

Sweet potato 2.1 80

*Sweet potato: App rate of 2.1 lb ai/Acre and 80 

Acres treated passes for DL/G PF5 R, SL/No G 

PF10 R, SL/G PF10 R, and DL/G PF10 R

7b Tractor Drawn Granular 

Spreader Applications Sweet potato 2.1 80

*Sweet potato: App rate of 2.1 lb ai/A and 80 

Acres treated passes with SL/G PF5 R, DL/G PF5 

R, SL/No G PF10 R, SL/G PF10 R, DL/G PF10 R

Recap - Example showing what is considered an individual crop use 

scenario
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• Group A. Use scenarios where DAS requests discussion on further refinement options

• Group B. Use scenarios where MOE > 100 for PPE/EC currently on the DAS product 

labels. 

• Group C. Use scenarios where rate mitigation may be possible for DAS uses to reach 

MOE of 100.

• Group D. Use scenarios proposed for further discussion with the Agency.

• Group E. Use scenarios not currently not on DAS labels.

• Group F. Use scenarios still undergoing further analysis by DAS

DAS: Current categories of draft use scenarios 
| 11

6

32

1

20 6

33

% of current total (276 use scenarios using MOE 

of 100)

A

B

C

D

E

F

Refer to previous slide for full explanation

Distribution of use scenarios by categories
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Discussion