UNITED ST A TES ENVIRONMENT AL PROTECTION AGENCY 

WASIDNGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

Da te: 03/20/2016 

Subject: Coumaphos: Registration Review Occupational Exposure Assessment for Use on 

Cattle, Cattle Ear Tags, Horses, Swine, Swine Bedding, and Beehives. 

PC Code: 03650 I 

Decision No.: 475453 

Petition No.: 

DP Ba rcode: 0410244 

Registra tion No.: See Use Profile 

Regulatory Action: Reg Review 

Risk Assessment Type: Occupational/Residential Exposure Assessment Case No.: 

TXR No.: NA CAS No.: 95266-40-3 

MRID No.: NA 40 CFR: §180.189 

From: 

Through: 

To: 

/]"7 ~~ 

Bridgett Bobowiec, Biologist -)j-t.e /7 .,/ ~ 

Branch VI 

Health Effects Division (7509P) 

Donna Davis, Branch Chief ((/\ 1() ~ .

7 ______./ 

B

Health 

ranch 

Eff

VI 

ects Division (7509P) 

~ ._.,.. ~ 

And . ~ ,7 

Barry O'Keefe, Senior Biologist ',q 0 tl..i.<J<., // 'J:;;?{ 

James S. Miller, Environmental Scientist .,.., ... - '--·~ "' /1-- ---.- Exposure Science Advisory Committee (fuq{oSAC) I HED 

Shelia Piper, Risk Assessor 

Branch VI 

Health Effects Division (7509P) 

And 

Brian Kettl, Chemical Review Manager 

Tom Myers, Team Leader 

Kevin Costello, Branch Chief 

Risk Management and Implementation Branch IV 

Pesticide Re-evaluation Division (7508P) 

Page I of29 
Introduction 

The Pesticide Reevaluation Division (PRD) requested that the Health Effects Division (RED) 

conduct an exposure and risk assessment for the currently registered uses of coumaphos as part 

of the registration review process. Coumaphos is registered for use on livestock including cattle, 

cattle ear tags, horses, swine as well as swine bedding, and bee hives. There are currently no 

registered non-occupational (residential uses) for coumaphos. 

It is HED policy to use the best available data to assess exposure. Several sources of generic 

data were used in this assessment as surrogate data in the absence of chemical-specific data, 

including: Pesticide Handlers Exposure Database Version 1.1 (PHED 1.1 ); and the Agricultural 

Handler Exposure Task Force (AHETF) database. Some of these data are proprietary, and 

subject to the data protection provisions of the Federal Insecticide, Fungicide, and Rodenticide 

Act (FIFRA). 

Note: This memorandum was reviewed by the Exposure Science Advisory Committee 

(ExpoSAC) on 10/31/2013. 

Page 2 of29 
Table of Contents 

1.0 Executive Summary .................................................................................................. ........... 4 

2.0 Risk Assessment Conclusions and Recommendations ........................................................ 7 

2.1 Summary of Risk Estimates ............................................................................................. 7 

2.2 Label Recommendations from Occupational Assessment.. ............................................. 7 

2.3 Data Deficiencies and Requirements ......................... ................................................ ... ... 8 

3.0 Hazard Characterization .............................................................................................. ......... 8 

4.0 Use Profile ............................ ............................................................................................. 11 

5.0 Residential Exposure and Risk Estimates .......................................................................... 14 

5.1 Residential Risk Estimates for Use in Aggregate Assessment ...................................... 14 

6.0 Non Occupational Spray Drift Exposures and Risk Estimates .......................................... 14 

6.1 Non-Occupational Bystander Post-Application Inhalation Exposure and Risk Estimates 

14 

7 .0 Occupational Exposure and Risk Estimates ...................................................................... 14 

7 .1 Occupational Handler Exposure/Risk Estimates ............................................................ 14 

7.2 Occupational Post-application Exposure/Risk Estimates .............................................. 28 

7.2. I Occupational Post-application Inhalation Exposure ............................................... 28 

7.2.2 Occupational Post-application Dermal Exposure ....................... ............................ 28 

Appendix A. Summary of Occupational Non-cancer Algorithms ... .... ........................................ 29 

Page 3 of29 
1.0 Executive Summary 

This document presents an occupational and residential exposure and risk assessment for the 

currently registered uses of coumaphos or (0, 0-diethyl 0-(3-chloro-4-methyl-2-oxo-2H-1 -

benzopyran-7-yl) phosphorothioate). It is a member of an organophosphate (OP) insecticide 

class that primarily affects the nervous system through acetylcholinesterase (AChE) inhibition. 

Coumaphos is applied directly to animals, including dairy cattle, beef cattle, swine, horses, and 

swine bedding. The chemical is also embedded into cattle ear tags and bee hive strips. 

Coumaphos is registered for the control of arthropod pests such as: ticks, mites, lice, flies 

(including face flies and horn flies), fleece wom1s, and screw worms. There are no registered 

non-occupational (residential) uses for coumaphos. 

Use Profile 

Coumaphos is formulated as a technical 96% active ingredient (a.i.), as well as a dust 

formulation intermediate (25%a.i.), a dust (I %a.i.), an emulsifiable concentrate (6.15 and 11.6 % 

a.i.), and a flowable concentrate (42%a.i.). Coumaphos is also embedded into cattle ear tags, 

(20% a.i) and bee hive pest control strips (10%a.i). 

The application of coumaphos to livestock can include use of the following equipment: swim and 

hydraulic dip vats, shaker cans, dust bags, back oilers/rubbers, pressurized handguns, backpack, 

handheld hand-wands, and ear tags. Application rates range from 0.005 to 0.025 lbs a.i. per 

gallon for sprays or dips, 0.076 lbs a.i. per gallon of oil for back-rubbers. 0.000625 to 0.013 lbs 

a.i. per animal for dust application, and 0.000042 lbs a.i. per 1,000 square feet of swine bedding 

treatment. 

There are various levels of personal protective equipment, or PPE, mandated on coumaphos 

labels depending on the formulation and application rate. Some of the higher rates for spray 

application require handlers to wear a single layer dennal protection with gloves and a PF I 0 

respirator, while some of the lower application rates do not require any respirators. Coumaphos 

dust formulations require handlers to wear a single layer dermal protection along with gloves and 

at least a Pf 5 respirator. 

This assessment addresses exposure and risk associated with the end use products for coumaphos 

when used as directed by occupational workers. There is a potential for occupational exposure 

associated with handler activities (i.e .. mixing, loading, and applying). Based on the Agency's 

current practices, a quantitative post-application inhalation and dermal exposure assessment and 

a spray drift assessment was not performed for coumaphos at this time due to the label directions 

and use pattern. 

Exposure Duration: 

For OPs such as coumaphos. matching the toxicological endpoint and the exposure duration is 

different than HED's approach for conventional chemicals. OPs exhibit a phenomenon known 

as steady state acetylcholinesterase (AChE) inhibition. Repeated exposures to OPs generally 

result in more AChE inhibition at a given administered dose compared to acute studies. 

Page 4 of29 
Moreover, AChE inhibition in repeated dosing guideline toxicology studies with OPs show a 

consistent pattern of inhibition reaching steady state at or around 2-3 weeks of exposure in adult 

laboratory animals (U.S. EPA, 2002). After repeated exposure at the same dose, the degree of 

inhibition comes into equilibrium with the production of new, uninhibited enzyme. As such, 

AChE studies of 2-3 weeks generally show the same degree of inhibition with those of longer 

duration (i.e. , up to 2 years of exposure). 

The steady state approach is appropriate for coumaphos given the toxicological and exposure 

profile. The ·'steady state,. endpoint selection for coumaphos overlaps with HED's traditional 

sho11-tenn exposure duration endpoint selection and is considered health protective for 

occupational handlers that apply commercially over longer periods of time (i.e., intermediateterm exposures). Chronic exposure is not expected for the registered use pattern so that duration 

was not considered. 

Hazard Profile 

The toxicology database for coumaphos is complete for risk assessment. There are acceptable 

data available for toxicity endpoint selection from studies across multiple lifestages, durations, 

and routes for both red blood cell (RBC) brain AChE inhibition. The acute toxicity of 

coumaphos is high via the oral route of exposure (Category I), moderate via the inhalation route 

(Category II), and slight via the dermal route (Category III). Coumaphos is not a dermal 

sensitizer or a dermal irritant and it does not cause delayed neuropathy. Coumaphos is negative 

for mutagenicity and in accordance with the Agency's Draft Cancer Risk Assessment Guidelines 

(July 2, 1999) is classified as "no evidence" of carcinogenicity for humans based on adequate 

studies in two animal species. 

Endpoints and points of departures (PoDs) using a steady state duration were selected for dermal, 

and inhalation routes of exposure. A steady state dennal PoD was selected from a 21-day dermal 

toxicity study (MRTD 4266640 1) in rats based on red blood cell, RBC ChE inhibition bench 

mark dose limit, BMDL10 = 0.5 mg/kg/day; and bench mark dose, BMD10 = 0.72 mg/kg/day) 

in the female rat. In the absence of a repeat dose inhalation study, a 2 generation oral 

reproduction study was used to select the steady-state inhalation PoD; a BMD10 of 0.05 

mg/kg/day associated with RBC ChE inhibition in both male and female adult rats of the FO and 

F 1 generations. The coJTesponding BMDL10 was 0.04 (0.036 rounded) mg/kg/day. An 

estimated 100% default absorption factor (of oral absorption) was assumed. 

A total uncertainty factor of 1 OOOX is appropriate for oral and dennal routes of exposures for 

occupational handlers and post-application exposure [1 OX for interspecies extrapolation, I OX for 

intraspecies variation, and FQPA SF for 1 OX safety factor is retained. A total uncertainty factor 

of 3000X [I OX for interspecies extrapolation, 1 OX for intraspecies variation, and 30X for 

database uncertainty factor] incorporating uncertainty in the human dose-response relationship 

for neurodevelopmental effects 1 and the uncertainty due to lack of subchronic inhalation toxicity 

study). The Hazard and Science Policy Council (HASPOC) (April 29, 2013. TXR 0056625) 

recommends, based on a weight of evidence (WOE) approach, that a subchronic inhalation study 

1 For more details, see Section 4.4 in the human health risk assessment: Memo, S. Piper et al, -2015, 0409347. 

Page 5 of29 
is needed to characterize the potential for adverse effects associated with the inhalation route of 

exposure. 

Residential Exposure/Risk: 

There are no registered non-occupational (residential) uses for coumaphos, and therefore a 

quantitative residential handl er and post-application assessment was not conducted. 

Non-Occupational Spray Drift Exposure and Risk 

A quantitative non-occupational spray drift assessment was not conducted for the registered uses 

of coumaphos due to the limited use pattern on livestock, horses, and in bee hives. 

Occupational Handler Exposure and Risk 

In order to detern1ine what level of personal protection is required to alleviate risk concerns and 

to ascertain if label modi ft cations are needed, steady state exposure and risk estimates were 

calculated for occupational handlers of coumaphos for a variety of scenarios at differing levels of 

personal protection including engineering controls. It is anticipated that there will be 

occupational handler short- and intermediate-term exposure to coumaphos; however, the steadystate tox endpoint overlaps the expected exposure durations and is health protective. Chronic 

exposure is not expected for the registered uses. 

Eight major handler exposure scenarios were assessed as follows: mixing/loading liquids for 

hydrauli c type dip vats; mixing/loading liquids for swim type dip vats; mixing/loading liquids for 

back rubber/oilers; loading dust into bags; applying dusts with a shaker can to livestock or swine 

bedding; mixing/loading/applying liquids for backpack, mechanically pressurized handguns, and 

manually pressurized handheld hand-wands. Exposure to coumaphos from handling and 

applying livestock ear tags and bee hive pest control strips is considered to be negligible because 

labels require gloves. A female-specific body weight of 69 kg was used to protect pregnant 

workers based on the uncertainty in the human dose-response relationship for 

neurodevelopmental effects2

. Default assumptions established by the HED Science Advisory 

Council for Exposure (ExpoSAC) were used for other parameters such as amount handled. HED 

continues to request more quantitative data. such as the number of cattle dipped per day, number 

of days dipping takes place per year, etc., to refine exposure to dip vat workers in quarantine 

areas under the animal and plant health inspection service, (APHIS) USDA program. 

A total aggregated risk index (ARI) approach was used as a risk metric to account for the 

different levels of concern (LOCs) between dermal (LOC = 1,000) and inhalation (LOC = 3,000) 

exposure. The target ARl is l; therefore. ARJs of less than I are risk estimates of concern. 

Almost all of the occupational exposure scenarios show risks of concern for both dermal and 

inhalation routes at varying levels of PPE. Calculations of risks indicate that the ART values are 

below 1 for all exposure scenarios except for mixing and loading back oil rubbers with the 

emulsifiable concentrate formulation. 

2 For more details, see Section 4.4 in the human health risk assessment: Memo, S. Piper et al, I 5-SEP-2015, 

0409347. 

Page 6 of29 
Occupational Post-Application Exposure 

Dermal post-application exposure is not anticipated due to the limited coumaphos use pattern 

and therefore was not included in this assessment. Coumaphos product labels include the 

language, "Do not contact treated animals unti l sprays have dried and dusts have settled on the 

coat." 

Based on the Agency's current practices, a quantitative non-cancer occupational post-application 

inhalation exposure assessment was not performed for coumaphos at this time. If new policies or 

procedures are put into place, the Agency may revisit the need for a quantitative occupational 

post-application inhalation exposure assessment for coumaphos. 

Human Studies Review 

This risk assessment relies in part on data from studies in which adult human subjects were 

intentionally exposed to a pesticide or other chemical. These data, which include studies from 

PHED 1.1 ; the AHETF database; and published literature studies, and are (1) subject to ethics 

review pursuant to 40 CFR 26, (2) have received that review, and (3) are compliant with 

applicable ethics requirements. For certain studies, the ethics review may have included review 

by the Human Studies Review Board. Descriptions of data sources, as well as guidance on their 

use. can be found at the Agency website3. 

2.0 Risk Assessment Conclusions and Recommendations 

2.1 Summary of Risk Estimates 

There are occupational handler inhalation and dermal risk estimates of concern for the currently 

registered uses for coumaphos. Occupational exposure scenarios using coumaphos flowable 

concentrates, emulsifiable concentrates and dust formulations were of concern (ARis < I) with 

the exception of mixing and loading liquid products EPA registration numbers 11 556-11 5 and 

11556-23 for livestock back oil rubbers (ARI = I with double layer dermal protection and PF5 

respirator). See Tables 7.1.1 through Table 7.1.9 for risk estimates. A spray drift assessment 

was not completed for the currently registered uses of coumaphos because of the use pattern is 

limited to livestock applications and beehives. 

2.2 Label Recommendations from Occupational Assessment 

A summary of the risk estimates have been provided, and shows that there are risk estimates of 

concern for registered uses of coumaphos based on the label-required personal protective 

equipment for occupational workers. Mechanical dusting is prohibited yet appears on some of 

the dust formu lated labels (Co-Ral Bulk Dust (1%) [34704-267, and Co-Rat (1%) [960-1 84]. 

3 hrrp://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/occupational-pesticide-handler-exposure-data 

and hrrp://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/occupational-pesticide-post-applicationexposure 

Page 7 of29 
Label corrections/revisions should be made to remove all mechanical dusting and inconsistent 

respirator requirements including the TC2 IC respirator nomenclature. 

2.3 Data Deficiencies and Requirements 

HED continues to recommend that registrants submit more information on quarantine dipping 

practices to comply with 40 CFR 158.1070 post-application guidelines including use pattern 

information (e.g., cattle dipped per day, number of days dipping takes place per year, and etc.) in 

order to clarify and refine exposure scenarios. 

3.0 Hazard Characterization 

Coumaphos is an OP with a neurotoxic adverse outcome pathway (AOP), also often called the 

mode of action (MOA). Inhibition of the enzyme acetylcholinesterase (AChE) via 

phosphorylation of the serine residue at the active site of the enzyme leads to accumulation of 

acetylcholine and ultimately to neurotoxicity in the central and/or peripheral nervous system. 

Consequently, AChE inhibition, as an indicator of neurotoxicity, is being used to derive the 

PoDs. HED's toxicologists have determined that the red blood cell (RBC) AChE inhibition is 

substantially more sensitive than brain AChE inhibition for all lifestages evaluated (adults, 

juveniles, pregnant dams, and fetuses) in oral and dermal studies. After repeated dosing at the 

same dose, the degree of inhibition comes into equilibrium with the production of new, 

uninhibited enzyme. At this point, the amount of AChE innibition at a given dose remains 

consistent across duration. After repeated exposure at the same dose, the degree of inhibition 

comes into equilibrium with the production of new, uninhibited enzyme. In general, OPs reach 

steady state within 2-3 weeks but this can vary among OPs. In the case of coumaphos, pattern of 

steady state is reached at or near 11 days of exposure. 

Coumaphos has high quality dose response data across multiple lifestages, durations, and routes 

for both RBC and brain AChE inhibition. Many of these studies have been evaluated using 

benchmark dose modeling techniques. In addition to the consistency across durations, the data 

across multiple studies (repeat CCA study, gestational data from the ONT, subcnronic 

neurotoxicity study, and subchronic rat toxicity study) are similar. For the purposes of the 

occupational and residential risk assessment, only the steady-state duration is relevant to the 

occupational exposure scenarios. Coumaphos is negative for mutagenicity and in accordance 

with the Agency's Draft Cancer Risk Assessment Guidelines (July 2, 1999) is classified as "no 

evidence" of carcinogenicity for humans based on adequate studies in two animal species. 

Acute Toxicity 

The acute toxicity of coumaphos is nigh via the oral route of exposure (Category I), moderate via 

the inhalation route (Category II), and slight via the dermal route (Category TIT). Coumaphos is 

not a dermal sensitizer or a dermal irritant. See Table 3. l. I for information on acute toxicity 

profile. 

Page 8 of29 
Table 3.1.1. Acute Toxicity Profile for Coumaphos 

Guideline No. Study Type MRID(s) Results Toxicity 

Category 

870. 11 00 Acute oral [rat] 00110597 

LDso (M) >240 mg/kg I 

LDso (F) = 17 mg/kg 

870.1200 Acute dermal [rabbit] 0011 0598 LDso: >2400 mg/kg lil 

870.1300 Acute inhalation [rat] 00110601 

LCso (M) = 1.081 mg/L 11 

LCso (F) = 0.341 mg/L 

870.2400 Acute eye irritation [rabbit] 00 11 0599 Mild Irritant. resolved by IV day 7 

870.2500 Acute dermal irritation [rabbit] 001 10600 No Irritation IV 

870.2600 Skin sensitization [guinea pig] 0011 0602 Non sensitizer NIA 

Toxicological PODs Used for Risk Assessment 

Dermal. Steady State 

A steady-state dermal PoD was selected from a 21-day dermal toxicity study (MRID 4266640 l) 

in rats based on RBC ChE inhibition (BMDL10 = 0.5 mg/kg/day; BMD10 = 0.72 mg/kg/day) in 

the female rat. It is noted that the female and male data for the second dermal study (that tested 

higher doses of 2, 4, 20 and 100 mg/kg/day) did not provide statistically acceptable results with a 

P-value of 0.05 using a log-likelihood ratio test for RBC AChE inhibition; however, visual 

observation of the data show a good fit and similar findings to the females in the study (BMDL10 

of 0.71 mg/kg/day). RBC AChE inhibition was significantly more sensitive than brain AChE 

inhibition (between 6 and 8.3 fold) in the dermal toxicity study. 

A total uncertainty factor of I OOOX is appropriate for dermal exposures (I OX for interspecies 

extrapolation, l OX for intraspecies variation, and a I OX FQP A safety factor due to uncertainty in 

the human dose-response relationship for neurodevelopmental effects4

) . 

Inhalation. Steady State 

In the absence of a repeat dose inhalation study, an oral study was used to assess a steady-state 

inhalation occupational exposure and risk. HED assumed that the time to reach steady-state is 

comparable for oral and inhalation exposure. A PoD for the steady-state inhalation exposure 

scenario was derived from the results of a 2-generation reproduction study (MRID 4306 1701 ). 

A BMD10 of 0.05 mg/kg/day associated with RBC ChE inhibition in both male and female adult 

rats of the FO and Fl generations from the 2-generation reproductive study was selected as a 

suitable PoD for the steady-state inhalation (all populations) exposure scenario. The 

corresponding BMDL10 was 0.04 (0.036 rounded) mg/kg/day. An estimated 100% default 

absorption factor (of oral absorption) was assumed. 

4 For more details, see Section 4.4 in the human health risk assessment: Memo, S. Piper et al, I 5-SEP-2015, 

0409347. 

Page 9 of29 
In some cases toxicity via the inhalation route is higher than toxicity via the oral route, which can 

result in an underestimation of risks from inhalation exposure if an oral PoD is used to estimate 

inhalation exposure. In addition, there may be a potential for portal of entry effects via the 

inhalation route, which would not be accounted for in the oral studies. As a result, the HASPOC 

(April 29, 2013, TXR 0056625) concluded that a subchronic inhalation study is needed for a 

more accurate assessment of inhalation risks. EPA applied an additional database uncertainty 

factor to account for the missing study. 

For steady-state inhalation exposures, a total uncertainty factor of 3000X was applied [1 OX for 

interspecies extrapolation, l OX for intraspecies variation, and a 30X FQPA safety factor due to 

uncertainty in the human dose-response relationship for neurodevelopmental effects5

, and a 

database uncertainty due a lack of a repeat inhalation toxicity study]. Based on the oral studies, 

lifestages sensitivity is not expected for the inhalation route of exposure. 

A summary of the toxicological doses and endpoints for use in the occupational exposure and 

risk assessment are provided in Table 3.1 .2. 

Table 3.1.2. Summary of Toxicological Doses and Endpoints for Coumaphos for Use in Occupational 

Human Health Risk Assessments 

Level of 

Exposure/ Point of Uncertainty Concern for 

Study and Toxicological Effects Scenario Departure Factors Risk 

Assessment 

Dermal 21-day dermal tox icity study (MRID 

Steady State BMDL10 = 0.5 UFA= I Ox Occupational 42666401) in female rats 

UFtt=IOx LOC for MOE = (2 1 days and mg/kg/day UFos =I Ox IOOO BMD10 = 0. 72 mg/kg/day for inhibition of longer) RBC ChE in adult female rats. 

BMDL10 = 0.04 2 generation reproductive study (MRID mg/kg/day Inhalation UFA= I Ox Occupational 43061701) 

Steady State Inhalation UF11=IOx LOC for MOE = (2 1 days and absorption UFos= 30x 3000 BMD10 = 0.05 mg/kg/day for Inhibition of 

longer) 100% of oral RBC ChE in f-oand F1 young adults at 90 days 

absorption in both males and females 

'- I 

Cancer (oral. 

dermal. Classification: no evidence of carcinogenicity to humans. 

inhalation) 

Point ofDepanure (POD) = A data point or an esumated point that is derived from observed dose-response data and used to 

mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human 

exposures. BMDL10 = lower confidence interval on the benchmark dose for 10% response. LOC = level of concern. For 

occupational dermal and inhalation scenarios, UFos =database uncertainty factor for uncertainty in the human dose-response 

relationship for ncurodevclopmental efTeets (see Section 4.4 of the human health risk assessment, 0409347). 

Absorption 

Previously, the HED HIARC determined that in the absence of demial absorption data and 

considering the observation that erythrocyte ChE inhibition is observed in both oral gavage and 

5 For more details, see Section 4.4 in the human health risk assessment: Memo, S. Piper et al, I 5-SEP-2015, 

0409347. 

Page 10of29 
dennal rat studies at similar dose levels, the default of l 00% absorption should be used. 

However, the steady-state dermal point of departure PoD was based on a route-specific toxicity 

study, and therefore no absorption factor was necessary to estimate exposure. 

Body Weight 

The body weights assumed for this assessment differ from those used in 2000 occupational and 

residential exposure assessment and are based on the recommendations of the 20 12 Residential 

SOPs. For adults, when an endpoint is not sex-specific (i.e., the endpoints are not based on 

developmental or fetal effects) a body weight of 80 kg is typically used in risk assessment; 

however, in this case, a female-specific body weight of 69 kg was used. While the endpoint of 

concern, brain AChE inhibition, is not sex-specific, the female-specific body weight was used to 

protect for pregnant women due to uncertainty in the human dose-response relationship for 

neurodevelopmental effects6. 

4.0 Use Profile 

Coumaphos is formulated as a technical 96% active ingredient, (a.i.) as well as a dust 

formulation intermediate (25%a.i.), a dust (1 %a.i.), an emulsifiable concentrate (6.15 and 

I l .6%a.i.), and a flowable concentrate (42%a.i.). Coumaphos is also imbedded into cattle ear 

tags, (20%a.i.) and bee hive pest control strips, (10%a.i.). Multiple applications to livestock 

and/or livestock areas are permitted during a one year period. There are however, label 

restrictions on the amount of livestock and livestock area treated per day. Applicators are 

restricted to spraying no more than 100 animals in one day and dusting no more than 25 animals 

in one day. In addition. applicators can dust no more than I 000 square foot of bedding in one 

day. 

Application of coumaphos to livestock can include the use of the following equipment: swim and 

hydraulic dip vats, shaker cans, dust bags, back oilers/rubbers, pressurized handguns, backpack, 

handheld hand-wands, and ear tags. Application rates range from 0.005 to 0.025 lbs a.i. per 

gallon for sprays or dips, 0.076 lbs a.i. per gallon of oil for back-rubbers, 0.000625 to 0.013 lbs 

a. i. per animal for dust application, and 0.000042 lbs a.i. per 1000 square feet of swine bedding 

treatment. There are vari ous levels of PPE mandated on the different labels depending on the 

formulation. Co-Ral Flowable, EPA registration number 11556-98. has the highest spray 

application rates and requires single layer attire with the addition of gloves and a PF I 0 respirator. 

EPA registration numbers 11556-115 and 11556-23 have lower spray application rates and do 

not require any respirators for handlers. The dust coumaphos formulations require baseline attire 

along with gloves and at least a Pf 5 respirator. 

Table 4.1.1 provides a summary of the registered uses of coumaphos for each of the 

formulations. Based on the registered use pattern for coumaphos, dermal and inhalation 

exposures are anticipated for occupational handlers. The registered uses are sorted in the table 

by the type of livestock, and in addition, includes the swine bedding, cattle ear tags, and bee hive 

sites. 

6 For more details, see Section 4.4 in the human health risk assessment: Memo, S. Piper et al, I 5-SEP-2015, 

0409347. 

Page 11 of29 
Tnble 4.J. Summnry of Directions fo r Use of Coumnphos. 

Max. 

Application Formulation Mnximum Mnx. No. Applicntion 

Timing, Type, (% ai.) Application Application Rate or Use Directions and Limitations 

and Equip. IEPA Reg. No.I Rate per Season Treatment 

Interval 

Cattle/Horses 

Swim Dip Vat RUP' and use is restricted to employees of the USDA APHIS2 who 

Cattle only 0.025 lbs arc enrolled in the USDA-API llS cholinesterase monitoring 

llydraulic Dip Co-Ral Flowablc Concentrate ai/gallon of 2 times/year Do not make program. Chnrgc dip vats with concentration of product and volume 

Vats (42%) spray applications 11.:ss of water. Do not tip excessively thirsty animals. Applicators using 

Cattle only than I 0 days handheld sprayers are limited to 100 animals arc day at maximum 

Manual and r 11556-981 0.021 lbs apart. application rate and 200 animals a day at Yi the maximum 

Mechanical Spray ai/gallon of 6 times/~car application rate. Apply as high pressure spray to wet the skin to runCattle and Horses sorav ofT. Repeat applications as necessary. Respirator requirement. 

Do not make 11.6 % is a RUP. Lactating and young cattle arc subject to lower 

applications less application rates. Do not apply rate above 0.0025 lb ai/gallon within 

Co-Ral Fly and Tick Spray (6. 1 S°/o) 14 days of freshening. Do not apply on animals less than 3 months 

Manual and [I 1556-115 J. 0.0 1 lbs than 10 days old. Do not spray animals for 10 day before shipping or weaning. 

Mechanical Spray And ai/gallon of 6 times/year apart. Label limits handler to I 00 applications to cattle a day and 200 a day Re-treatment Cattle and Horses Co-Ral Emulsifiable Livestock spray only necessary 

if treated at Yi the maximum application rate. Apply for complete 

Insecticide (11.6%) LI 1556-231 wetting to run-off. Do not contact treated animal unti l coats arc dry. when insects Do not spray in con lined area. Do not use in conjunction with other 

reappear. OPs. 

Co-Ral Fly and Tick Spray (6. 15% Re-treatment for dairy cattle suspend at height that will prevent straddling. No 

ai) (11556-115]. 0.076 lbs ai/ only necessary interval needed between treatment and slaughter or use of milk. 

!lack Rubbers Oil when insects Back rubber application for hom files and face flies. Mix specified 

Cattle And gallon of unknown 

reappear and dosage in I gallon of No. 2 fuel oil. Hang so no dairy cattle can Co-Ral Emulsifiable Livestock fue l 

Insecticide ( 11 .6%) [I 1556-23 J constitute a straddle. No interval required between treatment and slaughter or 

problem. milk use. 

Co-Ral Animal Insecticide (1%) I 0 days apart. Bulk Dust (11556-141. Shaker can: No interval 

Dust Bags and Co-Ral Shaker Can (I%) (11556-41. 0. 125 lbs 12 required Mechanical dusters arc prohibited. For lactating dairy cows suspend 

Shaker Can Co-Ral Bu lk Dust (1%) (34704-267). ai/bag times/year between bags in exit of mi lking barn. Limit number of animals can treat/day 

Cattle. Horses. Shaker Duster (I%) [69208-11 cows treatment and to no more than 25 animals and 1.000 feet of swine bedding. One 

Swine. Swine Y-Tex Co-Ral (1%) [39039-151. 0.0013 lbs 6 times/year slaughter or 12.5 lb duster per 25 animals. For direct application by shaker can 

D- Louse (I%) (34704-3061. animals dusted using no more 2 oz. of dust per animal. PPE baseline Bedding Diolicc ( 1%) l2393-378]. of ai/cattle horses between plus gloves. unknown treatment and Co-Ral (I%) [960-184], use of milk. Ziocide Dust Bag (I%) [960-169 i 

Page 12 of29 
Table 4.1. Summarv of Directions for Use of Coumaohos. 

Max. 

Application Formulation Maximum Max. No. Application 

Timing, Type, (% ai.) Application Application Rate or Use Directions and Limitations 

and Equip. !EPA Reg. No.I Rate per Season Treatment 

Interval 

Ear Tags Coraihon ( 15%) [11556-1481. 0.5 oz ( 14 grams ) per tag. Wear chemical resistant glove when 

Beef and Non And 20%a.i., Replace as necessary applying tags. All mature animals should be tagged. Attach one tag 

Lactating Dairy Co-Ral Plus Insecticide Cattle Ear 15% to each car. Do not use on cattle less than 3 months old. 

CaHle Tag (20%) [1 1556-1231 Remove tags at end of ny season prior to slaughter. 

Swine 

Co-Ral Emulsifiable Livestock 

Insecticide ( 11 .6%) f 1 1556-14 ), 

Co-Ral Shaker Can (1%) [11556-4). Do not make Co-Ra I 13ulk Dust (I%) 134 704-267). 0.000625 6 times a applications less Mechanical dusters arc prohibited. Limit number of pig can treat 

Shaker Can Shaker Duster ( 1 %) [69208-1 ], lbs ai/pig year than 10 days per day to 25. Do not enter allow contact with animals until dust has 

Y-Tcx Co-Ral (!%) [39039-15], settled. 

D- Louse (I%) [34 704-306]. apart. 

Diolicc (1%) [2393-3781. 

Co-Ra I (I%) !960-1841 

Co-Ral Fly and Tick Spray (6. 15% Do not make Label limits handler to 100 applications to swine a day at maximum 

0.005 lbs ai/ application rate. Do not contact treated animal until coats are dry. Mcchnnical and ai) 111556-115]. and Co-Ra! 

gallon of 6 timcs a applications less Do not spray animals for 10 days before shipping or weaning. Do Manual Spray Emu lsiliablc Livestock Insecticide year than 10 days not spray in confined area. Do not use in conjunction with other (11.6%) [ 11 556-231 spray apart. OPs. 

Swine Bedd ing 

Co-Ral Emulsiliable Livestock 

Insecticide (11.6%) ( 11556-14). Do not make Co-Ra I Bulk Dust (I%) [34 704-267. 4.5xJO·S 6 times a applications less Apply 2 oz. uniformly over 30 square feet of fresh dry bedding. Shaker Can Shaker Duster ( 1%) 169208-1 ). lbs ai/rt2 year than 10 days Limit area of swine bedding treated per day to I 000 ft2 

D- Louse (1%) [34704-3061, 

Diolice (I%) [2393-3781. apart. 

Co-Ra I (I%) f960- I 84 I 

Bee Hives 

Chcckmitc .,. Bee Hive Pest Control 10'%ai by Twice a year for Varroa mites 

Bee Hive Strips Strip (I 0%ai) [ 11556-138) weight and no more than four times Leave strips in hive for at least .J2 days but not over 45 days. 

for small hive beetle. I Rcstncttd u.., Ptsticidc (RUP) 

2 U.S Dcpanmcnt of Agriculture An1111 nl and Plant Health Inspection Service (USDA·APHIS) 

Page 13 of29 
5.0 Residential Exposure and Risk Estimates 

There are cmTently no registered non-occupational (residential) uses for coumaphos at this time. 

5.1 Residential Risk Estimates for Use in Aggregate Assessment 

There are no registered non-occupational (residential) uses of coumaphos. Based on the labeled 

use pattern and the exposW'e profile of coumaphos, there is no recommended residential 

contribution to the aggregate risk assessment. 

6.0 Non Occupational Spray Drift Exposures and Risk Estimates 

Spray drift is a potential source of exposure to those nearby pesticide applications. This is 

particularly the case with aerial application, but, to a lesser extent, spray drift can also be a 

potential soW'ce of exposure from the ground application methods (e.g., groundboom and 

airblast). The approach is outlined in the revised (2012) Standard Operating Procedures For 

Residential Risk Assessment (SOPs) - Residential Exposure Assessment Standard Operating 

Procedures Addenda I: Consideration of Spray Drift. This document outlines the quantification 

of indirect non-occupational exposure to drift. Coumaphos is not applied nor registered on use 

sites that are likely to result in spray drift. Therefore, a spray drift analysis is not included in this 

assessment. 

6.1 Non-Occupational Bystander Post-Application Inhalation Exposure and Risk 

Estimates 

Volatilization of pesticides may be a source of post-application inhalation exposure to 

individuals nearby pesticide applications. The agency sought expert advice and input on issues 

related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act 

Scientific Advisory Panel (SAP) in December 2009, and received the SAP's final report on 

March 2, 2010 (http://www.regulations.gov/#!documentDetail:D=EPA-HO-OPP-2009-0687-

0037). The agency has evaluated the SAP report and has developed a Volatilization Screening 

Tool and a subsequent Volatilization Screening Analysis 

(http://www.regulations.gov/#!docketDetail:D=EPA-HQ-OPP-20 14-0219). 

During Registration Review, the agency will utilize this analysis to determine if data (i.e., flux 

studies, route-specific inhalation toxicological studies) or further analysis is required for 

coumaphos. 

7.0 Occupational Exposure and Risk Estimates 

7.1 Occupational Handler Exposure/Risk Estimates 

HED uses the term handlers to describe those individuals who are involved in the pesticide 

application process. H ED believes that there are distinct job functions or tasks related to 

applications and exposures can vary depending on the specifics of each task. Job requirements 

(amount of chemical used in each application), the kinds of equipment used. the target being 

Page 14 of29 
treated, and the level of protection used by a handler can cause exposure levels to differ in a 

manner specific to each application event. 

Based on the anticipated use patterns and current labeling, types of equipment and techniques 

that can potentially be used, occupational handler dermal and inhalation exposure is expected 

from the proposed uses. Applying ear tags to cattle and inserting pest control strips into bee 

hives was not quantitatively assessed. The exposure to these tasks was considered negligible 

based on the product formulation and glove requirement. Therefore, the quantitative 

exposure/risk assessment developed for occupational handlers is based on the following 

scenarios: 

• mixing/loading flowable concentrate for hydraulic type dip vats, 

• mixing/loading flowable concentrate for swim type dip vats, 

• mixing/loading flowable and emulsifiable concentrate for back rubber/oilers, 

• loading dust into bags, 

• applying dust with a shaker can to livestock, 

• applying dust to swine bedding via shaker can, 

• mixing/loading/applying liquid sprays for backpack, 

• mixing/loading/applying liquid sprays for mechanically pressurized handguns, and 

• mixing/loading/applying liquid sprays for manually pressurized hand-wands. 

Occupational Handler Exposure Data and Assumptions 

A series of assumptions and exposure factors served as the basis for completing the occupational 

handler risk assessments. Each assumption and factor is detailed below on an individual basis. 

Application Rate: 

Application rates range from 0.005 to 0.025 lbs a.i. per gallon for sprays or dips, 0.076 lbs a.i. 

per gallon of oil for back-rubbers, 0.000625 to 0.013 lbs a.i. per animal for dust application, and 

0.000042 lbs a.i. per 1000 square feet of swine bedding treatment. Cattle ear tags are 20% 

coumaphos by weight and the bee hive strips are 10% coumaphos by weight. See Table 4.1.1 for 

a summary of the registered uses of coumaphos for each of the coumaphos formulations. 

Unit Exposures: 

It is the policy of HED to use the best available data to assess handler exposure. Sources of 

generic handler data, used as surrogate data in the absence of chemical-specific data, include 

PHED 1.1, the AHETF database or other registrant-submitted occupational exposure studies. 

Some of these data are proprietary (e.g., AHETF data), and subject to the data protection 

provisions of FlFRA. The standard values recommended for use in predicting handler exposure 

that are used in this assessment, known as "unit exposures", are outlined in the "Occupational 

Pesticide Handler Unit Exposure Surrogate Reference Table7

", which, along with additional 

7 A vai lab le: http://www2.epa.gov/sites/production/files/2015-09/documents/handler-exposure-table-2015 .pdf 

Page 15 of29 
information on HED poli cy on use of surrogate data. including descriptions of the various 

sources, can be found at the Agency website8

. 

Area Treated or Amount Handled: 

The an1ount treated or amount handled was based on guidance in HED ExpoSAC Policy 9.1, 

language on the labels, and HED's best professional judgement of tank and catt le herd sizes. 

The previous assessment memo (0267778, R. Sandvig, August 3, 1999) cited the chemical 

specific study, Reassessment of Operator Exposure and Risk for the Animal Spray and Dip Uses 

ofCoumaphos dated June 10, 1997. For this current assessment, the same quantity estimates for 

handler exposure to dip vats were used. Hydraulic-type dip vats are estimated to hold 1,800 

gallons and swim dip vats can hold 4,000 gallons. Handlers are estimated to mix and load 14 

gallons of mixture for back oil rubbers. Cow herd sizes were row1ded to represent small and 

large farm operations for applicators loading and hanging dust bags. Herd sizes were estimated 

as 100 cows, 350 cows, and 500 cows. It is not expected that dust bags or oil back rubbers 

would be used on very large farms as it would require a lot of material and time to hang in order 

to be efficacious. Dust application via shaker can is restricted on the label to 25 animals a day 

and 1000 ft2 of bedding a day. Therefore, it assumed an applicator would handle the 

corresponding amount of material. Applicators are restricted to spraying no more than l 00 

animals in one day at the maximum application rate with handheld equipment and 200 animals a 

day at one half the maximum application rate. Mechanically pressurized handguns are estimated 

to hold 1,000 gallons of spray; however, using the language from the labels this amount was 

lowered to 400 gallons of spray a day while manually pressurized hand wand and backpack 

application were assumed 40 gallons of spray a day based on policy guidance. 

Body Weight 

For adults, when an endpoint is not sex-specific (i.e., the endpoints are not based on 

developmental or fetal effects) a body weight of 80 kg is typically used in risk assessment; 

however, in this case, a female-specific body weight of 69 kg was used. While the endpoint of 

concern, RBC AChE inhibition, is not sex-specific, the female-specific body weight was used to 

protect for pregnant women due to uncertainty in the human dose-response relationship for 

neurodevelopmental effects9. 

Abs01ptionfactors: 

A dermal toxicity sn1dy is the basis of dermal points of departure, a dermal absorption factor is 

not required. 

Exposure Duration: 

8 Ava i I ab le: http ://www2 .epa. gov/pesticide-science-and-assessing-pest ic ide-risks/occu pat i ona I-pesticide-handlerex posu re-data 

9 For more details, see Section 4.4 in the human health risk assessment: Memo, S. Piper el al, 15-SEP-2015, 

0409347. 

Page 16of29 
HED typically classifies exposures from l to 30 days as short-term and exposures 30 days to six 

months as intermediate-term. Exposure duration is determined by many things, including the 

exposed population, the use site, the pest pressure triggering the use of the pesticide, and the 

cultural practices surrounding that use site. For OPs, the match between the toxicological 

endpoint selection and the exposure duration is different than HED's approach for conventional 

chemicals. The endpoint selection for organo phosphate pesticides involves a "steady state" 

approach based on an individual chemical's cholinesterase inhibition. The "steady state" 

endpoint selection for coumaphos overlaps HEO's traditional steady state-term endpoint 

selection as well as being appropriately health protective for occupational handlers that apply 

commercially over longer periods of time (i.e., intennediate-term exposures). 

For most agricultural uses, it is reasonable to believe that occupational handlers will not apply 

the same chemical every day for more than a one-month time frame; however, there may be a 

large agribusiness and/or commercial applicators who may apply a product over a period of 

weeks (e.g. completing multiple applications for multiple clients within a region). 

Coumaphos can be toxic to livestock if over applied so it is assumed most farmers will only 

apply when pests are an issue. However, there is no quantitative data such as number of cattle 

dipped per day, number of days dipping takes place per year, etc. HED continues to request 

more quantitative data, such as the number of cattle dipped per day, number of days dipping 

takes place per year, etc., to refine exposure to dip vat workers in quarantine areas under the 

animal and plant health inspection service, (APHI S) USDA program. 

Mitigation/Personal Protective Equipment: 

Estimates of dermal and inhalation exposure were calculated for various levels of PPE. Results 

are presented for '·baseline," defined as a single layer of clothing consisting of a long sleeved 

shirt, long pants, shoes plus socks, no protective gloves, and no respirator, as well as baseline 

with various levels of PPE as necessary (e.g., gloves, respirator, etc). The coumaphos product 

labels direct mixers, loaders, applicators and other handlers to wear baseline attire with chemical 

resistant gloves. Co-Ral Flowable, EPA Reg. No. 11 556-98 has the highest spray application 

rates and requires handlers to wear a PFlO respirator. EPA Reg. Nos. 11556-115 and 11 556-23 

have lower spray application rates and do not require any respirators for handlers. The various 

dust formulations require baseline attire along with gloves. Protective eyewear, shield, and 

apron are also listed on some of the labels. These types of PPE address the acute toxicity 

categories of the chemical. See previous Table 3. 1.1 for acute toxicity coumaphos summary. 

HED does not consider a face shield equivalent to a respirator nor an apron over long sleeve shirt 

equivalent to double layer protection. 

Occupational Handler Non-Cancer Exposure and Risk Estimate Equations 

The algorithms used to estimate non-cancer exposure and dose for occupational handlers can be 

found in Appendix A. The toxicological PoDs for inputs can be found in the previous Table 

3.1.2. 

Page 17 of29 
Combining Exposures/Risk Estimates: 

A total aggregated risk index (ARI) was used since the toxicological effects for the dermal and 

inhalation exposure routes were similar (RBC cholinesterase inhibition), because the LOC values 

for dermal exposure (I 000) and inhalation exposure (3000) are different. The target ARI is I; 

therefore, ARis of less than I are risk estimates of concern. The algorithm used to estimate 

combined non cancer exposure for occupational handler can be found in Appendix A as well. 

Summary of Occupational Handler Non-Cancer Exposure and Risk Estimates 

Based on the labeled PPE for occupational handlers for the various formulations, there are risk 

estimates of concern identified (i.e., dermal MOEs < 1000 and inhalation MO Es < 3000) for the 

steady-state exposure assessment. Combined occupational handler risk estimates are presented 

using the ARI approach with a target of 1. 

There are dermal and inhalation risk estimates of concern for all formulation types and exposure 

scenarios except for back oil rubber appli cations. The products are sorted by formulation type 

(e.g., tlowable, emulsifiable concentrate, and dust) with corresponding registration numbers. 

Risk estimates are presented in the following tables Table 7.1.1. - Table 7. 1.9 with the unit 

exposures for each formulation presented in a separate table. The unit formulation tables are 

then followed by scenario specific inhalation and dermal exposure risk estimates and then lastly 

followed by the ARI estimate tables. The following list provides a summary of the scenarios that 

resulted in risk estimates of concern: 

• The USDA cholinesterase monitoring program scenarios include gloves and PFl 0 

respirator and result in ARis < 1. At label level PPE ARls range from 0.003 to 0.06. 

ARis range from 0.006 to 0.08 with PPE increased to double layer dermal protection and 

a PF 10 respirator. 

• The liquid coumaphos products that require gloves but no respirator also result in risk 

estimates of concern. At label level of PPE ARis range from 0.002 to 0.7. ARls range 

from 0.03 to 1.1 with PPE increased to double layer dermal protection and a PF 10 

respirator. 

• The dust formulations require gloves and at least a PF5 respirator and result in result in 

ARls < 1. At label level PPE ARls range from 0.003 to 0.28. ARls range from 0.006 to 

0.46 with PPE increased to double layer dermal protection and a PF I 0 respirator. 

Page 18 of29 
Table 7. 1.1. Dermal and Inhalation Unit Exposures fo r Co-Ral Flowable Insecticide, REG # 11556-98 

EC 

Denna! Unit Exposures (ug/lb ai)1 

Application Equipment I Application Rate2 I Amount Handled I Arca Treatcdl ' 

SL/G I DL/G EC No-R PF5 R I PF IO R I SL/No G 

Inhalation Unit Exposures (ug/lb ai)1 

Mixer/Loader - -- 00219 j 0 Swim Dip Vat 0.025 4000 220 37.6 29. 1 8.6 0.2 19 0.0438 lb ai/gallon of dip gallons/day 

I lyclraulic Dip Vat 0.025 1800 220 37.6 29. 1 8.6 0.2 19 0.0438 0.0219 0 lb ai/gallon of dit) gallons/day 

0.083 

.083 

Mixer/Loader/ Applicator 

-- _, 

Backpack 0.02 1 40 25 10 2500 1600 ND I 30 I 6 I 3 

r-=- lb ai/gallon gallons - -i - Manually-pressuri:1cd I landwancl 0.02 1 40 100000 430 365 ND 30 6 I 3 lb ai/gallon _ - - gallons ~ 

- - -

ND 

ND 

_J 

ND_ J 

Mechanically-pressurized Handgun 0.021 100 1800 6~0 365 ND 79 15.8 7.9 lb ai/gallon gallons - Mechanically-pressurized Handgun 0.02 1 400 1800 640 I 365 ND 79 15.8 7.9 lb ai/gallon gallons 

I. Based on the "Occupational Pesticide Handler Unit Exposure Surrogate Reference Table (September 2015). PPE represented includes SL= baseline dermal (long sleeved shirt, long pants. shoes 

and socks). SL/G baseline dermal plus gloves, DL/G= coverall over baseline dermal plus gloves. EC= closed system. NR = no respirator: PF5 = ""Protection Factor 5", indicating a reduction in 

exposure of 80%: PFIO = ··Protection Factor IO" indicating a reduction in exposure of 90%. 

2. Based on registered label Co-Ral Flowable Insecticide Reg ff 11556-98. Label is restricted use to employees enrolled in the USDl\-1\PHIS cholinesterase monitoring program 

3. Exposure Science Advisory Council Policy #9. 1.and assumptions from Memo 0262059. Reassessment of Operator Exposure and Risk for the Animal Spray and Dip Uses ofCoumaphos June 10. 

1999 and EXPOSAC discussion 03114/2013. 

Page 19 of29 
Table 7. 1.2. Steady State-Term Du ration Occupational Dermal and Inhalation Handler Non-Cancer Exposure and Risk Estimates fo r Co-Ral Flowablc Insecticide, REG# 11 556-98 

I Amount ,___Qermal Dose (mg/kg/day)J Dermal MOE7 

EC I No-R 

Inhalation Dose (mg/kg-dav)5 Inhalation MOE6 

Application Application Handled 

SL/ SL/G DL/ EC Equipment Rate1 I Area SL/ SL/G DL/ I PF5 R PFIO R EC No ~0 EC 

Treated2 NoG G NoG G R R R 

Mixer/Loader 

0.025 4000 Swim Dip Vat lb ai/gallon gallons 0.3 19 0.0545 0.042 0.0 13 1.6 9.2 12 40 0.0003 6.35E-05 3. 17E-05 0.00012 11 0 570 11 00 300 

of dip - 1 lydraulic Dip 0.025 1800 lb ai/gallon 0.143 0.025 o.o 19 I 0.006 3.5 20 26 89 0.0001 2.86E-05 I .43E-05 5.42E-05 250 1300 2500 660 Vat ofdiQ gallons . ~ I 

Mixer/Londer/Annlicator 

Backpack 0.021 40 0.03 1 0.030 0.019 ND 16 16 26 ND 0.0004 7.3E-05 3.65E-05 

NO =1 99 490 990 ND lb ai/gallon gallons 

Manually- 0.02 1 40 

pressurized lb ai/gallon gallons 1.22 0.005 0.004 ND 0.41 96 11 0 NO 0.0004 7.3E-05 3.65E-05 ND 99 490 990 ND 

Handwand 

Mechanically- 0.021 100 

pressurized lb ai/gallon gallons 0.055 0.019 0.011 ND 9. 1 26 45 ND 0.002 4.&E-04 2E-04 ND 15 75 150 ND 

Handgun - Mechanically- 0.02 1 400 

pressurized 0.078 I 0.045 lb ai/gallon gallons 0.2 19 ND 2.3 6.4 11 ND 0.01 0.002 0.00 1 ND 3.7 19 37 ND 

Hands?.Un I I 

I Based on registered label Co-Ral Flowablc Insecticide Reg# 11556-98. Label is restricted use to employees enrolled in the USDA-A Pl-I IS cholinesterase monitoring program 

2 Exposure Science Advisory Council Policy /19.1.and assumptions from Memo D262059. Reassessment of Operator Exposure and Risk for the Animal Spray and Dip Uses of Coumaphos June I 0. 

1999 and EX PO SAC discussion 03/ 14/2013 

3 Dermal Dose= Dem1al Unit Exposure (μg/lbs a.i.) x Application Rate (lbs a.i./acre or gal) x Arca Treated or Amount Handled Daily (A or gal/day) ..;. BW (kg). 

4 Dermal MOE = Dermal NOAEL (mg/kg/day) ..;. Demial Dose (mg/kg/day) 

5 Inhalation Dose = Inhalation Unit Exposure (pg/lbs a.i.) x Conversion Factor (0.00 I mg/μg) x Application Rate (lbs a.i./acre or gal) x Area Treated or Amount Handled Daily(/\ or gal/day)..;. BW 

(kg). 

6 Inhalation MOE = Inhalation NOAEL (mg/kg/day)+ Inhalation Dose (mg/kg/day). 

Page 20 of29 
Table 7. 1.3. Steady state-Term Duration Occupational ARI Handler Non-Cancer Exposure and Risk Estimates for Co-Ra I Flowable Insecticide, REG# 11556-981 

Application Equipment 

I 1\pplication I /\mount Handled I Area ARl

4 

Rate2 TrcatcdJ SL/No G + I SL/G + I DIJG + I SL/G + I DIJG + SL/G + ---~------' ___ No-R . No-R _ No-R _ PF5 R _ PF5 R PF I 0 R 

Swim Dip Vnt 

0.025 

lb ai/gallon of 

dip 

4000 

gallons 

Mixer/Loader 

0.00 15 0.0074 0.009 0.0088 0.0 11 0.009 

I LIG +~ 

PFI~ "' --

o.o 12 I 0.029 

Hydraulic Dip Vat 

0.025 

lb a i/gallon of 

di 

0.0034 0.016 0.02 0.019 O.Q25 0.02 1 soo I L----i gallons O.D25 I 0.063 

--- --~- xe oa pplic r 

I 0.021 1-·- 40 I I I Backpack lb .

1 II II 0.0 11 0.011 1----------- ai ga on ga ons _ . ~ 

Manually-pressurized 0.02 1 40 

_ _ 1 landwand lb ai/ allon _ gallons _,_ 

0.015 

0.0004 0.025 O.Q25 

I 0.015 I 0.022 0.015 

---+---------- 0.06 0.066 

--- 0.024 NO 

0.074 0.083 NO 

Mechanically-pressurized 0.02 1 100 

Handgun lb ai/gallon gallons 0.0032 0.0042 0.0045 0.013 0.016 0.0 17 0.024 ND 

Mechanically-pressurized I 0.02 1 I 400 

I landgun lb ai/gallon gallons 0.0008 0.00 1 0.00 11 0.0032 0.004 0.0042 0.0058 ND 

I Based on the "Occupational Pesticide Handler Unit J:::xposurc Surrogate Reference Table (September 2015). Level of mitigation represented in table include: SL= baseline dermal (long sleeved 

shirt, long pants. shoes and socks). SL/G baseline dermal plus gloves. DL/G= coverall over baseline dermal plus gloves. EC= closed system. NR = no respirator: PF5 = ··Protection r:actor 5". 

indicating a reduction in exposure of 80%: PF I 0 = "Protection Factor IO" indicating a reduction in exposure of 90%. 

2 Based on registered label Co-Ral Flowable Insecticide Reg# 11556-98. Label is restricted use to employees enrolled in the USDA-/\ PHIS cholinesterase monitoring program 

3 Exposure Science Advisory Council Policy #9. 1.and assumptions from Memo 0262059. Reassessment of Operator Exposure and Risk for the Animal Spray and Dip Uses of Coumaphos June I 0. 

1999 and EXPOSAC discussion 03114/2013 

4 ARI = Aggregate Risk Index= I+ [(Oennal LOC + Dermal MOE) + (Inhalation LOC + Inhalation MOE)]. 

Page 21 of29 
Table 7.1.4 Steady state-Term Duration Unit Exposures fo r Liquid Formulations Reg #s. 11556- 11 5, and 11556-23 

Application Equipment Target Application Rate2 Amount Handled I Arca Dermal Unit Exposures (ug/lb ai)1 Inhalation Unit Exposures (ug/lb ai)1 

'-

Category Treated3 SL/No G SL/G DL/G EC No-R Pf-5 R PFIO R EC 

Mixer/Loader 

13ack Oil Rubbers I Cattle I 0.07617 I 14 l 220 37.6 29.1 8.6 I 0.219 0.0438 0.0219 0.083 lb ai/ gallon gallons/day 

Mixer/Loader/ Applicator 

Backpack Cattle 0.01 

'- lb ai/1!.a llon 40 25 10 2500 1600 ND 30 6 3 ND 

Backpack Swine 0.005 gallons 

lb ai/gallon --

Manually-pressurized 1-fandwand Cattle 0.01 

I lb ai/gallon 40 

0.005 gallons 100000 430 365 ND 30 6 3 ND 

Manually-pressurized Handwand Swine lb ai/gallon - - Mechanically-pressurized Handgun Callie 0.01 100 1800 640 365 ND 79 15.8 7.9 ND lb ai/gallon gallons 

Mechanically-pressurized Handgun Swine 0.005 100 1800 640 365 ND 79 15.8 7.9 ND 

- lb ai/gallon gallons - -

Mechanically-pressurized Handgun Cattle 0.01 400 1800 640 79 15.8 7.9 ND lb ai/gallon gallons 

~ I I - 0.005 400 

1 I I I Mechanically-pressurized Handgun I Swine 1800 640 D 79 15.8 7.9 ND lb aill!.allon gallons 

I Based on the .. Occupational Pesticide Handler Unit Exposure Surrogate Reference Table (September 2015). PPE represented includes SL= baseline dennal (long sleeved shirt. long pants. shoes 

and socks). SL/G baseline dermal plus gloves. DL/G= coverall over baseline dermal plus gloves, EC= closed system. NR = no respirator: PF5 = .. Protection Factor 5'', indicating a reduction in 

exposure of80%; Pf-10 = ··Protection Factor 10" indicating a reduction in exposure of90%. 

2 Based on registered label Co-Ral Flowable Insecticide Reg II 11 556-98. Label is restricted use to employees enrolled in the USDA-A PHIS cholinesterase monitoring program 

-

3 Exposure Science Advisory Council Policy 119. 1.and assumptions from Memo D262059. Reassessment of Operator Exposure :md Risk for the Animal Spray and Dip Uses of Coumaphos June I 0. 

1999 and EXPOSAC discussion 03/ 1412013. 

Page 22 of 29 
Table 7. 1.5. Stead 'rm Duralion Occupational llandler Non-Cancer Exposure and Risk Estimates for Liquid Formuhllions Reg #s. 11 556-11 5, and 11556-231 =] 

Applica1ion I Amount 

I Demlal MOE~ I 

Denna! Dose (mg/kg/day)' lnhala1ion Dose (mg/kg-dayt Inhalation MOE' 

Application Target I ~~ 1 

s~ I 0~1 I . Equipment Category Rate1 llandlcd' SI.I SLIG DL/G I EC EC No-R PF5 R I PFIO R I EC No-R 1 1'1"5 R PFIO R EC NoG I 

1\1 ixe r/Loader 

Dack Oil 0.076 17 14 I 3.391::- 6.77E- 3.39E· J 1.2812 

Rubbers Callie lb ail gallon gallons/ 0.003 0.0006 0 0005 0.000 1 150 860 1100 3800 06 07 07 -06 11 000 53000 1 !0000 28000 

day 

1\lixc r/Loader/Applicator - 0.01 

54 I 1.7E- 3.48E- I - Backpack Callie 0.0 15 0.015 0.009 34 34 1.14F.- I 210 IOOO 2100 lb ai/gallon 40 04 05 05 

0.005 I gallons ND ND 1.7..JE- 8.7F.- ND I ND 

Backpack $\1ine 0007 0.007 0.005 69 69 110 9F.-05 ..JIO 2100 41 00 

I-- - lb ai/gallon . 05 06 -. --- Manually- 0.0 1 1.74E- 3...J8E- l.74E- pressurized Callie lb ai/gallon 0.58 0.003 0.002 0.86 200 240 04 05 05 210 1000 2100 

llandwand 40 - ND ND ND ND Manually- 0.005 gallons 8.7E- l.74E- 8.7Epressurized Swine lb ai/gallon 0.146 ND 0.001 1.7 400 470 05 OS 06 410 2100 4100 

Hand wand 

Mechanical 0.0 1 100 I. I 4E- 2.29Epressuri zed Ca Ille lb ai/gallon gallons 0.026 0.009 0.005 ND 19 54 95 ND 03 04 I E-04 ND 32 160 320 ND 

Hande.un 

Mechanical 0.005 JOO 

I 10 I 5.72E- 1.14E- 5.72E- I pressuri zed Swine lb ai/gallon gallons 0.0 13 0.005 0.003 ND 38 190 ND 04 04 05 ND 63 320 630 ND 

Handgun 

Mechanical ~ 

-

pressurized Caulc 0.01 400 0. 10..J 0.037 0.02 1 ND ..J.8 13 2-1 ND ..J.58E- 9.16E- 4.58E- ND 7.9 39 79 ND 

llandgun lb ai/gallon gallons 03 0..J 04 

Mechanical 0.005 400 2.291::- ..J.58E- 2.29E· 

pressurized Swine lb ailgallon gallons 0.052 0.019 0.011 ND 9.6 27 47 ND 03 04 04 ND 16 79 I 160 ND 

Handgun --- - - - -·- Oascd on lhc "Occ11pn1ional Pesticide Handler Uni1 Ex posure Surrogmc Reference Table (S::ptcmber 2015). PPE rcpresenlcd includes SL= baseline dcmial (long slecvcd shir1. long pru11s. shoes and socks), SL/G baseline 

demial plus gloves. Dl...IG= coverall over baseline dcrmul plus gloves. EC= closed sys1em. NR = no rcspira1or: PF5 = .. Pro1ection Factor 5". indicaiing a reduction in exposure of 80%: Pf I 0 = "Protcc1io11 Faaor IO" 

indicating a rcduc1ion in exposure of90%. 

2 13ascd on registered coumaphos labels Reg # 11556-11 5 and 11 556-23. 

3 Exposure Science Advisory Council Policy #9. 1.and assumptions from Memo 0262059. Reassessment of Operator Exposure and Risk for 1hc Animal Spray and Dip Uses of Coumaphos June I 0, 1997. EXPOSAC 

discussion 03/1 4/20 13 . 

..J Dcm1al Dose= Dcnnal Uni1 Ex posure (11g/lbs ai.)" Applicmion Raic (lbs ai./acrc or gal) x Arca Tn.:mcd or Amount I landled Daily (A or gal/day)+ BW (kg). 

5 Dcm1al MOF. - Dcnnal NOA EL (mg/kg/day) + Dennal Dose (mg/kg/day). 

6 lnhala1ion Dose = lnhala1im Unit Exposure (μg/lbs a.i.) x Conversion Factor (0.00 1 111g/11g) x Applica1ion Rate (lbs ai/acrc or gal) x Arca Treated or Amount Handled Daily {J\ or gal/day)+ BW (kg). 

7 Inhalation MOE = Inhalation NOA EL (mg/kg/day) + l11hala1im Dose (mg/kg/day). 

Page 23 of29 
Table 7.1.6. Steady State-Term Duration ARJ Occupational Handler Non-Cancer Exposure a nd Risk Estimates for Liquid Formulations Reg #s. 11 556-115, a nd 11 556-231 

Application Crop I Appl ication Amounl 1 landlcd ARI~ 

Application Equipment Type Targcl Raic2 I Area Trcated3 SL!No G + SL/G+ OLIG + SL/G + DL/G + SL/G+ T DL/G+ EC Category No-R No-R No-R PF5 R PF5 R PFIO R PFIO R - Mixer/Loader 

I I I 0.076 172 14 

Back Oil Rubbers I I Broadcast Cattle lb ai/ gallon gallons 0.14 0.7 0.85 0.82 I 0.84 I. I 2.7 

mixture - Mixer/Loader/Applicator 

0.0 1 40 003 - Backpack Broadcast Cattle lb a i/ga llon !!a lions 0.023 0.031 0.046 0.032 0.05 ND 

Backpack Broadcast Swine 0.005 40 0.046 0.046 0.06 1 0.063 0.095 0.066 0. 1 ND lb ail!?allon gallons 

Manual ly-prcssurized Broadcast Callie 0.01 40 0.00085 0.052 0.054 0.13 I 0.14 0. 16 0. 18 ND 

Hand wand lb ai/gallon gallons . - Manually-pressurized Broadcast Swine 0.005 40 0.0017 0. 1 0. 11 0.25 0.28 0.31 0.35 NO Handwand lb ai/11.allon gallons 

Mechanically- Broadcast Callie 0.0 1 100 0.0068 0.0089 0.0096 0.027 0.034 0.036 0.05 ND pressurized I landgun lb ai/gallon 1!.a llons 

- Mechanically- Broadcasl Swine 0.005 100 0.0 14 0.0 18 0.0 19 0.054 0.068 0.072 0.1 2 ressurized 1 landgun lb ai/gallon ND j gallons 

I Mechanically- 0.0 1 400 

~ressurized 1 landgun Broadcast Cattle lb ai/gallon • gallons 0.0017 0.0022 0.0024 0.0065 I 0.0084 0.0087 0.013 ND 

Mechanically- Broadcast Swine 0.005 400 0.0034 0.0045 0.0048 0.013 J_ 0.0 17 I 0.0 18 O.Q25 ND 1 orcssurizcd I landgun lb ai/aallon gallons 

Ba:;ed on the "Occupational Pesticide Handler Unit Exposure Surrogate Reference Table (Seplcmber 20 15). PPE represented includes SL= baseline dermal (long sleeved shirt. long pants. shoes 

and socks). SL/G baseline dermal plus gloves, DL/G= covernll over baseline dermal plus gloves. EC= closed system. NR = no respirator: PFS ="Protection Factor 5", indicating a reduction in 

exposure of80%: PF IO = "Protection Factor 10" indicating a reduclion in exposure of90%. 

2 Based on registered coumaphos labels Reg# I 1556-1 I 5 and I I 556-23. 

3 Exposure Science Advisory Council l)olicy #9. 1.and assumptions from Memo 0262059. Reassessment of Operator Exposure and Risk for the Animal Spray and Dip Uses of Coumaphos June I 0. 

1997. EXPOSAC discussion 03/14/2013. 

4 ARI= Aggrcga1e Risk Index = J.;. f(Dcmial LOC .;. Dermal MOE)+ (Inhalation LOC .;. Inhalation MOE)!. 

Page 24 of29 
Table 7. 1.7. Occupational Handler Derma l and Inha lation Unit Exposures for Dust Based Formulations and Impregna ted Material 

Crop I Target Category 

Amount I land led I Dermal Unit Exposures (ug/lb ai)1 Inhalation Unit Exposures (ug/lb ai}1 

Arca Trcatcdl - } Applio"ioo Rme' 

I l -- -

Appl ication Equipment 

Value Value SL/No G SL/G DUG EC No-R PF5 R PFI O R EC Units Units I ---- - -- - Mixer/Loader 

Dust bag Small Cattle Farm 0.0096 15 I 100 227 51.6 41.2 I ND 8.96 1.79;--r 0.896 ND lb ai/catt le cattle 

0.0096 15 i >- --- Dust bag Medium Cattle 350 227 5 1.6 4 1.2 N D 8.96 

~ 0.896 ND Farm lb ai/cattle I cattle 

Dust bag Large Cattle Fann 0.009615 500 227 51.6 41.2 ND 8.96 0.896 ND lb ai/cattle cattle ~- .. 

App'tator - Shaker can Cattle or Horse 0.00 125 25 4042000 11 0000 72600 ND 17500 3500 1750 ND lb ai/cow or horse Cows or horses 

Shaker can Swine 0.000625 25 4042000 11 0000 72600 ND 17500 3500 1750 ND lb ai/o!!. pigs - - - -

Shaker can Swine Bedding 4. I 7E-05 IOOO 4042000 110000 72600 ND 17500 3500 1750 ND lb ai/ft2 fi2 ·- Impregnated Material Non Dust formu lations 

EarTag9 Cattle 20% a. i./tag Neglig ible exposure 

Bee Mite Strip9 Bee hives I 0% a.i./strip Negligible exposure J - - I Based on the ""Occupational Pesticide 1 landler Unit Exposure Surrogate Reference Table (September 2015). PPE represented includes SL= basel ine dermal (lo ng sleeved shirt. long pants. shoes 

and socks). SL/G baseline dermal plus g loves. DL/G= coverall over baseline dennal plus g loves. EC= closed system. NR = no respirator: PF5 =··Protection Factor 5". indicating a reduction in 

exposure of 80%: PF I 0 = ' 'Protection Factor IO" indicating a reduction in exposure of 90%. 

2 Based on registered coumaphos dust and solid fonnulated labels. 

3 Exposure Science Advisory Council Policy #9. 1.and assumptions from Memo 0262059. Reassessment of Operator Exposure and Risk for the Animal Spray and Dip Uses of Coumaphos June I 0. 

1997. EXPOS/\C discussion 03114/2013. 

Page 25 of29 
Table 7. I .8. Steady Stat(}-Term Occupational Handler Non-Cancer Exposu re and Risk Estimates for Dust Based Formulations a nd Impregnated Material' 

Crop / Amount Dermal Dose (mg/kg/day)4 Dermal MOE5 Inhalation Dose (mg/kg-day)6 Inhalation MOE7 

Application Application Handled I 

Equipment Target Rme2 Arca Sl./No G SL/G DL/G SL/No SL/G DL/G No-R PF5 R PF IO R No- PF5 PFIO 

Category Treatcd3 G R R R 

Mixer/Loader 

Dust bag 

Small 0.009615 JOO 0.00316 0.00072 0.0006 160 700 870 I J.25E-04 2.49E-05 I .25E-05 290 I 1400 I 2900 Cattle Fann lb ai/cattle cattle 

Dust bag 

Medium 0.009615 350 0.0 111 0.00252 0.0020 45 200 250 4.3E-04 8.74E-05 4.38E-05 82 410 820 Cattle Fam1 lb ai/cattle cattle - 0.0096 15 500 Dust bag Large 0.0158 0.00359 0.0029 32 140 170 6.25E-04 l.25E-04 6.25E-05 58 290 580 Cattle Farm lb a i/cattle cattle 

Aoolicator 

Cattle and 0.00125 25 I Shaker can lb ai/cow or Cows or 1.83 0.0-199 0.0329 0.27 10 15 7.93E-03 I .58E-03 7.93E-04 4.5 23 45 I lorses horse horses -

Shaker can Swine 0.000625 25 0.9 16 0.0249 0.0 164 0.55 20 30 3.96E-03 7.93E-04 3.96E-0-1 9.1 45 9 1 lb ai/011 p_igs 

Shakcrean Swine 4. 17E-05 1000 2.43 0.0664 0.0439 0.2 1 7.5 II l.06E-03 2. 12E-03 l.06E-03 3.4 17 34 Bedding lb ai/112 n2 -

>------ - Impregna ted Material Non Dust formulations 

EarTag9 Callie 1 20% a.i./tag Negligible exposure 

Bee Mite Strip9 Bee hives ' I 0% a.i./strip Negligible exposure - Based on the .. Occupational Pesticide I landler Unit Exposure Surrogate Reference Table (September 2015): Level of mitigation represented in table includes baseline inhnlmion and additional PPE 

required gloves (G) a nd a PFS r espirator. It is noted that the labds suggests that handlers could utilized more protective equipment however it docs not appear to be a requirement on various 

dust labels. 

2 Based on registered coumaphos dust :ind solid formu lated labels 

3 Exposure Science Advisory Council Policy #9.1.and assumptions from Memo D262059. June 10, 1997. Dust bag estimates arc best judgments utilizing fann surveys from memo. EXPOSAC 

discussion 03/ 14/2013 

4 Dermal Dose= Denna! Unit Exposure (pg/lbs a.i.) x Application Rate (lbs a.i./acrc or gal) x Area Treated or Amount Handled Daily (A or gal/day) .;. BW (69kg). 

5 Dermal MOE = Dem1al NOAEL (mg/kg/day) .;. Dem1al Dose (mg/kg/day). 

6 Inhalation Dose = Inhalation Unit Exposure (μg/lbs a.i.) x Conversion Factor (0.00 I mg/11g) x Application Rate (lbs a.i./ gal.) x Arca Treated or Amount I land led Daily (A or ga l/day) .;. BW 

(69kg). 

7 Inhalation MOE = Inhalation NOAI]. (mg/kg/day) .;. Inhalation Dose (mg/kg/day). 

Page 26 of29 
Table 7. 1.9. Steady State-Term ARI Occupationa l Handler Non-Cancer Exposure and Risk Estimates for Dust Based Formulations• 

Target Application /\mount Handled I Art:a /\Rl

4 

Application Equipment Category Rate2 Treated3 SL!No G + SL/G + DLIG + SL/G + DL/G + SL/G + DL/G + PFIO R No-R No-R No-R PF5 R Pf-5 R PF IO R 

Mixer/Load er 

Dust bag Small Cattle 0.0096 15 100 0.06 0.085 0.087 0.28 0.3 0.4 1 0.46 Farm lb ai/cattle cattle 

Dust bag Medium 0.0096 15 350 0.0 17 0.024 0.025 0.081 0.088 0. 12 0. 13 Cattle Fam1 lb ai/cattlc cattle 

Dust bag Large Cattle 0.0096 15 500 0.0 12 0.0 17 0.017 0.057 0.062 0.08 1 0.09 Farm lb ai/eattlc cattle 

Applicator 

Shaker can Cattle 0.00 125 25 0.00023 0.0013 0.00 14 0.0043 0.005 1 0.006 0.0075 lb ai/cow cows 

Shaker can Swine 0.000625 25 0.00047 0.0026 0.0028 0.0086 0.0 1 0.0 12 0.0 15 lb ai/pJ:! pigs 

Shaker can Swine 4. 17E-05 1000 0.000 18 0.00098 0.001 0.0032 0.0037 0.0045 0.0056 Bedding lb ai/ft2 ft2 

Based on the .. Occupational Pesticide 1 landlcr Unit Exposure Surrogate Rdcrenee Table (September 2015): Level of mitigation represented in table includes baseline inhalation 

and additional PPE r equired gloves (G) and a PFS respirator. It is noted that the labels suggests that handlers could utilized more protective equipment however it docs not 

appear to be a requirement on various dust labels. 

2 Based on registered coumaphos dust and solid formulated labels. 

3 Exposure Science Advisory Council Policy #9. 1.and assumptions from Memo 0262059. June 10, 1997. Dust bag estimates are best judgments utilizing fann surveys from 

memo. EXPOS/\C discussion 03114/2013 

4 /\RI = Aggregate Risk Index = I+ [(Dt:rmal LOC + Dermal MOE) + (Inhalation LOC + Inhalation MOE)J 

Page 27 of29 
7.2 Occupational Post-application Exposure/Risk Estimates 

HED uses the term post-application to describe exposures that occur when individuals are 

present in an environment that has been previously treated with a pesticide (also referred to as reentry exposure). Such exposures may occur when workers enter previously treated areas to 

perform job functions, including activities related to crop production, such as scouting for pests 

or harvesting. Post-application exposure levels vary over time and depend on such things as the 

type of activity, the nature of the crop or target that was treated, the type of pesticide application. 

and the chemical 's degradation properties. In addition, the timing of pesticide applications, 

relative to harvest acti vities, can greatly reduce the potential for post-application exposure. 

7.2.1 Occupational Post-application Inhalation Exposure 

There are multiple potential sources of post-application inhalation exposure to individuals 

performing post-application activities in previously treated fields. These potential sources 

include volatilization of pesticides and resuspension of dusts and/or particulates that contain 

pesticides. The agency sought expert advice and input on issues related to volatilization of 

pesticides from its Federal Insecticide, Fungicide. and Rodenticide Act Scientific Advisory Panel 

(SAP) in December 2009, and received the SAP's final report on March 2, 2010 

(http://www.regulations.gov/#!documentDetail ;O=EPA-HQ-OPP-2009-0687-003 7). The agency 

has evaluated the SAP report and has developed a Volatili zation Screening Tool and a 

subsequent Volatilization Screening Analysis 

(http://www.regulations.gov/#!docketDetail;D=EPA-HQ-OPP-2014-0219). During Registration 

Review, the agency will utilize this analysis to determine if data (i.e., flux studies, route-specific 

inhalation toxicological studies) or further analysis is required for coumaphos. In addition, the 

Agency is continuing to evaluate the available post-application inhalation exposure data 

generated by the Agricultural Reentry Task Force. Given these two efforts. the Agency will 

continue to identify the need for and, subsequently, the way to incorporate occupational postapplication inhalation exposure into the agency's risk assessments. 

7.2.2 Occupational Post-application Dermal Exposure 

Dermal post-application exposure is not anticipated due to the limited coumaphos use pattern on 

livestock and embedded ear and beehive strips, and therefore was not included in this 

assessment. 

Restticted Entry Interval 

Coumaphos is classified as Toxicity Category Ill via the dermal route and Toxicity Category IV 

for skin irritation potential. Jt is not a skin sensitizer. Under 40 CFR 156.208 (c) (2) (iii), a.i. 's 

classified as Acute ITI or IV for acute dem1al, eye irritation and primary skin irrigation are 

assigned a 12-hour REI. However, in the worker protection standard (WPS) (40 CFR 170.103: 

Exceptions), there is an exception for pesticides applied "on livestock or other animals, or in or 

about animal premises.,. Therefore, coumaphos labels do not fall under WPS. Language on 

coumaphos end use product labels should retain statements such as, "Do not contact treated 

animals until sprays have dried and dusts have settled on the coat." 

Page 28 of29 
Appendix A. Summary of Occupational Non-cancer Algorithms 

Potential daily exposures for occupational handlers are calculated using the following formulas: 

where: 

E 

UE 

AR 

A 

E=UE *AR* A * 0.001 mg/ug 

exposure (mg ai/day), 

unit exposure (μg ai/lbs ai), 

maximum application rate according to proposed label (lbs ai A or lbs ai/gal), and 

area treated or amount handled (e.g., A/day, gal/day). 

The daily doses are calculated using the following fom1ula: 

where: 

ADD 

E 

AF 

BW 

£*AF 

ADD= --

BW 

average daily dose absorbed in a given scenario (mg ai/kg/day), 

exposure (mg ai/day), 

absorption factor (dennal and/or inhalation), and 

body weight (kg). 

Margin of Exposure: Non-cancer risk estimates for each application handler scenario are calculated using a Margin 

of Exposure (MOE), which is a ratio of the toxicological endpoint to the daily dose of concern. The daily dennal 

and inhalation dose received by occupational handlers are compared to the appropriate POD (i.e., BMDL10) to assess 

the risk to occupational handlers for each exposure route. All MOE values are calculated using the following 

formula: 

where: 

MOE 

POD 

ADD 

BMDL10= 

POD 

MOE=-

ADD 

margin of exposure: value used by HED to represent risk estimates (unit less), 

point of departure (mg/kg/day), and 

average daily dose absorbed in a given scenario (mg ai/kg/day). 

bench mark dose limit. 

The aggregate risk index (ARl) was calculated as follows: 

Aggregate Risk Index (ARl) = I + (I + Rldm11a1) + (I + Rl1111ia1a11mJ 

Where: 

Risk Index {RI) = MOE + LOC 

Page 29 of29