Date: 

Subject: 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

March 28, 2016 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

Aldicarb. Occupational and Residential Exposure Assessment in Support of 

Registration Review. 

PC Code: 09830 I DP Ba rcode: 0430949 

Decision No.: 498310 Registr at ion No.: 48210-1 

Petition No.: NA Regula tory Action : Registration 

Review 

Ris k Assessment Type: Occupational/Residential Exposure Assessment Case No.: 70 16 

TXR No.: NA CAS No.: 116-06-3 

MRID No.: 4385250 1 40 CFR: 180.269 

From: 

Through: 

To: 

Introduction 

Matthew Lloyd, CIH, Industrial HygieniJt j D f ~ -fi7 

Risk Assessment Branch Vll ~ Health Effects Division (7509P)

1 

J} J. J / 

Michael Metzger, Chief J } J} · ~V Risk Assessment Branch VIJ lf l flvl\. · 

Health Effects Division (7509P) 

and 

Wade Britton, Industrial Hygienist 

Josh Godshall, Biologist;iExposure Science Advisory Commit e (ExpoSAC) I HED 

Sue Barlow, Chemical Review Manager 

Tom Myers, Team Leader 

Risk Management and Implementation Branch II 

Pesticide Re-Evaluation Division (7508P) 

The Pesti cide Re-evaluation Division (PRO) requested that the Health Effects Division (HED) 

conduct an exposure and risk assessment for the registered uses of aldicarb as part of registration 

review. This memorandum contains HED's occupational/residential exposure and risk 

Page I of26 
assessment required during registration review to reflect the updated science policies and 

procedures. 

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 (PI-!ED 1.1 ); the Agricultural 

Handler Exposure Task Force (AHETF) database; other registrant-submitted exposure 

monitoring studies (MRID 4385250 I). Some or 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 0610411 5. 

Page 2 of26 
Page 3 of 26

Table of Contents

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

2.0 Risk Assessment Conclusions and Recommendations........................................................ 6

2.1 Summary of Risk Estimates............................................................................................. 6

3.0 Hazard Characterization....................................................................................................... 6

4.0 Use Profile ........................................................................................................................... 9

5.0 Residential Exposure and Risk Estimates.......................................................................... 12

6.0 Non-Occupational Spray Drift Exposure and Risk Estimates................................................ 12

7.0 Non-Occupational Bystander Post-Application Inhalation Exposure and Risk Estimates..... 12

8.0 Occupational Exposure and Risk Estimates ...................................................................... 13

8.1 Occupational Handler Exposure/Risk Estimates............................................................ 13

9.2 Occupational Post-application Exposure/Risk Estimates .............................................. 19

9.2.1 Occupational Post-application Inhalation Exposure/Risk Estimates...................... 19

9.2.2 Occupational Post-application Dermal Exposure/Risk Estimates.......................... 20

Appendix A. Summary of Occupational and Residential Non-cancer Algorithms..................... 21

Appendix B. Summary of Available Occupational Handler Exposure Data............................... 24
Page 4 of 26

1.0 Executive Summary

The Health Effects Division (HED) has conducted an exposure and risk assessment for the 

registered uses of aldicarb as part of registration review. This memorandum contains HED’s 

occupational/residential exposure and risk assessment required during registration review to 

reflect the updated science policies and procedures. 

Aldicarb [2-methyl-2-(methylthio)propanal O-[(methylamino)carbonyl]oxime] is a carbamate 

insecticide that is marketed only as a granular product (with either low-dust corn cob grit or

vinyl-coated gypsum-based substrates) with a concentration of 15 percent active ingredient. 

Aldicarb is used to control soil borne pests including mites, various insects, and nematodes on 

dry beans, sugar beets, cotton, peanut, sweet potato, and soybean.

The label-required Personal Protective Equipment (PPE) varies depending on the handling 

scenario & packaging of the formulation (i.e., substrate of the granular formulation). For open 

pour handling, the PPE is coveralls over a long-sleeved shirt and long pants, chemical-resistant 

gloves made of any waterproof material, and chemical-resistant footwear plus socks. In addition, 

during loading, equipment cleaning or repair, or spill clean-up, the labeling requires handlers to

wear protective eyewear (goggles or face shield), a chemical-resistant apron, and a NIOSHapproved respirator with a dust/mist filter. The exception to the above PPE requirements are 

when engineering controls (i.e., a closed loading/application system) are used. The restricted 

entry interval (REI) on the current labeling is 48 hours.

In acute lethality studies, aldicarb is highly toxic via the oral, dermal, and inhalation routes of

exposure (Toxicity Category 1). It is not a dermal sensitizer, but due to severe effects (death) 

following corneal and dermal dosing, dermal and eye irritation studies were waived. Aldicarb 

toxicity studies have demonstrated cholinesterase inhibition (ChEI) activity in whole blood, 

plasma, red blood cells (RBC) and brain of rats, mice, and dogs following acute, subchronic, and 

chronic exposures and in plasma and RBC in humans following acute exposure. The 

toxicological endpoints selected for the dermal and inhalation routes of exposure were based on a 

common toxic effect (RBC ChEI) from an intentional dosing human oral study1; therefore, these 

routes were combined for the occupational exposure and risk assessment. For the occupational 

risk assessment, the level of concern (LOC) is for Margins of Exposure (MOEs) less than 10. 

There are no currently registered residential uses. The potential for spray drift exposure is 

considered negligible because of the aldicarb product formulation (granular) and immediate 

soil incorporation of the product.

There is potential for occupational handler exposure. The occupational assessments were 

completed based on an available chemical-specific occupational exposure monitoring study2

(used to assess the use of PPE during open pour/open cab applications) and based on surrogate 

data [i.e., the Pesticide Handlers Exposure Database (PHED); used to assess the use of 

 

1 Ethics Review Available: at http://www.epa.gov/osa/hsrb/files/april2006mtgfinalreport62606.pdf

2 Worker Loader and Applicator Exposure to Temik 15G (10/12/95) Sponsor: Rhone Poulenc Ag Company, 2 TW Alexander 

Drive, Research Triangle Park NC 27709 (EPA MRID 438525-01)
Page 5 of 26

engineering controls during applications]. Occupational handlers are assessed assuming shortand intermediate-term dermal and inhalation exposure. There is no quantitative post-application 

assessment based on the limited exposure potential since aldicarb is soil incorporated.

For the open pour/open cab application scenarios, using chemical-specific unit exposure data and 

assuming use of label required PPE (i.e., a double layer of clothing and a standard filtering 

facepiece respirator), there are combined dermal and inhalation risk estimates of concern (i.e., 

MOEs are < 10) for two scenarios. Mixer/loader risk estimates are of concern for the use on 

sugar beets at 4.95 lb ai/A (MOE = 4.5) and 3 lb ai/A (MOE = 7.4). For the closed

loading/closed cab application scenarios (i.e., engineering controls), using available surrogate 

unit exposure data for engineering controls, all combined dermal and inhalation risk estimates 

are of concern (i.e., MOEs ≤ 10).

The registered aldicarb granular product, which has either a low-dust corn cob grit or vinylcoated gypsum-based substrate, is considered a low-dust formulation relative to the available 

surrogate unit exposure data from PHED (which is based on clay-based substrate granular 

formulations). Exposure and risk estimates for handlers using the closed loading scenarios may 

be considered overestimates as the PHED surrogate unit exposures are based on granular 

formulations which are “dustier” than the low-dust formulations such as the aldicarb products 

(low-dust corn cob grit and vinyl-coated gypsum based substrates).

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

inhalation exposure assessment was not performed for aldicarb 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 aldicarb.

Human Studies Review

An intentional dosing human oral study was used for selection of points of departure in prior risk 

assessments. This study has been reviewed by EPA’s HSRB, as required by EPA’s Human 

Subjects Protections Rule (40 CFR part 26 (effective April 7, 2006)). The HSRB discussed the 

study extensively during a meeting held on April 2-4, 2006 and concluded that the cholinesterase 

data from the aldicarb human study were reliable for use in the aldicarb single chemical

aggregate risk assessment. Additionally, it was concluded that there was no clear and convincing 

evidence of significant deficiencies in the ethical procedures that could have resulted in serious 

harm (based on the knowledge available at the time the study was conducted), nor that 

information provided to participants seriously impaired their informed consent. The final report 

of the HSRB is available at http://www.epa.gov/osa/hsrb/files/april2006mtgfinalreport62606.pdf.

The PHED has been reviewed from an ethics perspective and no issues were found which 

would preclude its use in the risk assessment process. The chemical-specific study (MRID 

43852501) was also reviewed for ethical requirements pertaining to the usability of data and 
Page 6 of 26

found to be acceptable for risk assessment.3 Descriptions of data sources, as well as guidance 

on their use, can be found at the Agency website4. 

2.0 Risk Assessment Conclusions and Recommendations

There are occupational handler risk estimates of concern for several scenarios, depending on the 

application equipment/formulation combination, including both the open pour/open cab and 

closed loading/closed cab systems.

There is no aldicarb chemical-specific data for closed loading systems (i.e., engineering 

controls); therefore, HED used surrogate unit exposure values from PHED to quantitatively 

calculate risk estimates for closed loading systems. Risk estimates for closed loading systems are 

of concern (MOEs< the LOC of 10) for both loading and applicator handler scenarios. However, 

exposure and risk estimates for handlers using the closed loading scenarios may be considered 

overestimates as the PHED surrogate unit exposures are based on a clay-based substrate granular 

formulation which is “dustier” than low-dust formulations such as the aldicarb products (lowdust corn cob grit and vinyl-coated gypsum based substrates).

There is no quantitative risk assessment for residential exposure because there are no registered 

residential uses. In addition, there is no quantitative spray drift assessment based on the granular 

formulation type and the soil incorporation. There are no exposure data requirements for 

aldicarb.

2.1 Summary of Risk Estimates

The following summarizes the occupational handler risk estimates based on the available toxicity 

and exposure data. 

Open Mixing/Loading and Open-cab Application Using Label-specified PPE:

 Mixer/loader scenarios (using chemical-specific data):

o Sugar beets at 3 & 4.95 lbs ai/A (MOEs = 7.4 and 4.5, respectively)

Closed Mixing/Loading and Closed-cab Application (i.e., engineering controls):

 Mixer/loader scenarios (using surrogate exposure data):

o All scenarios (total MOE ranges from 0.12 to 0.99 based on a LOC of 10)

 Applicator scenarios (using surrogate exposure data):

o All scenarios (total MOEs ranges from <1 to 3.9 based on a LOC of 10)

3.0 Hazard Characterization

Aldicarb has an adequate toxicity database to conduct human health risk assessment. 

Acute Toxicity

 

3 HSRB Report: http://www.epa.gov/osainter/hsrb/files/meeting-materials/apr-4-6-2006-publicmeeting/april2006mtgfinalreport62606.pdf

4 http://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/occupational-pesticide-handler-exposure-data
Page 7 of 26

In acute lethality studies, aldicarb is highly toxic via the oral, dermal, and inhalation routes of

exposure (Toxicity Category 1). It is not a dermal sensitizer, but due to severe effects (death) 

following corneal and dermal dosing, dermal and eye irritation studies were waived.

Table 3.0.1 Acute Toxicity Profile – Aldicarb.

Guideline No. Study Type MRID(s) Results Toxicity 

Category

870.1100 Acute oral - Rat 00057333 LD50 = 0.8 mg/kg/day I

870.1200 Acute dermal -

Rat

00091241

00069916

LD50 = 20 mg/kg/day, water

LD50 = 5 mg/kg, propylene glycol

I

870.1300 Acute inhalation -

Rat

00069916

00057333

LC50 < 0.007 mg/L I

870.2400 Acute eye 

irritation - Rabbit 00069916 No corneal irritation at lethal dose N/A

870.2500 Acute dermal 

irritation - Rabbit 00069916 None at fatal levels N/A

870.2600 Skin sensitization 

- Guinea Pig N/A N/A N/A

Toxicological Points of Departure (PODs) Used for Risk Assessment

Aldicarb toxicity studies have demonstrated inhibition of cholinesterase activity in whole blood, 

plasma, red blood cells (RBC) and brain of rats, mice, and dogs following acute, subchronic, and 

chronic exposures and in plasma and RBC in humans following acute exposure. It should be 

noted that aldicarb-induced ChEI has been shown to be reversible in less than 24 hours. Both the 

acute and subchronic rat neurotoxicity studies show a variety of typical clinical signs of ChEI 

after oral exposures to aldicarb, including decreased motor activity, lacrimation, tremors, 

salivation, pinpoint pupils, and decreased grip strength. Aldicarb did not result in developmental 

toxicity in either rats or rabbits or in reproductive effects in the rat multi-generation reproduction 

study. Additionally, there was no developmental toxicity in the developmental neurotoxicity 

study in rats.

In an acute oral study conducted in human volunteers, aldicarb treatment of both males and 

females resulted in statistically significant inhibition of both RBC and plasma cholinesterase. 

The results of the acute oral human study suggest a two-fold difference between animals and 

humans with respect to toxic responses following acute exposure to aldicarb, with human being 

the more sensitive species. HED selected a Benchmark Dose Level (BMDL10) as a point of 

departure for the dermal and inhalation routes of exposure [0.013 mg/kg/day] based on RBC 

ChEI. 

The human study was reviewed by the Human Studies Review Board (HSRB), who concluded 

that use of the human study endpoint was appropriate for human health risk assessment. Because 

these human data are considered reliable, and the study is considered scientifically valid, at this 
Page 8 of 26

time the Agency considers the human study to be the most suitable for the single-chemical risk 

assessment. 

The specific toxic effect (cholinesterase inhibition) is common to the dermal, and inhalation 

routes; therefore, these routes can be combined for risk assessment.

For the occupational risk assessments, the level of concern (LOC) is for MOEs less than 10. The 

LOC is based on a 10X for intra-species, and a 1X for interspecies (reduced from 10X) because 

the endpoint is derived from a human study.

Aldicarb is classified as not likely to be carcinogenic to humans, based on the lack of evidence of 

carcinogenicity in studies in rats and mice and the absence of a mutagenicity concern. 

Therefore, an exposure assessment for cancer risk assessment is not required.

Table 3.0.2. Summary of Toxicological Doses and Endpoints for Aldicarb for Use in Risk Assessments.

Exposure

Scenario

Point of 

Departure

Uncertainty/ 

FQPA 

Safety 

Factors 1

Level of 

Concern for 

Risk 

Assessment

Study and Toxicological Effects

Dermal Exposures 

(Short- and 

Intermediate-Term) 

BMDL10 = 0.013 

mg/kg/day

DAF = 100%

UFH = 10

UFA= 1x

LOC for 

MOE = 10X

Human oral study

MRIDs 43829602, 45068601, 

43442302, 43442305, 42373001

BMD10 = 0.02 mg/kg, based on 

RBC cholinesterase inhibition

Inhalation 

Exposures (Shortand IntermediateTerm) BMDL10 = 0.013 

mg/kg/day

UFH = 10

UFA= 1x

LOC for 

MOE = 10X

Human oral study

MRIDs 43829602, 45068601, 

43442302, 43442305, 42373001

BMD10 = 0.02 mg/kg, based on 

RBC cholinesterase inhibition

Cancer

Classification: Aldicarb is classified as Category E, Evidence of Non-Carcinogenicity 

for Humans, based on the lack of evidence of carcinogenicity in studies in rats and mice 

and the absence of a mutagenicity concern. 

Point of Departure (POD) = A data point or an estimated 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. NOAEL 

= no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty factor. UFH = potential 

variation in sensitivity among members of the human population (intraspecies). UFA = extrapolation from animal to human 

(interspecies); to human is not warranted due to the PoD based on human RBC cholinesterase data. BMDL10 = Benchmark Dose 

estimate based on the lower 95% confidence interval where 10% ChEI would be observed. MOE = margin of exposure. LOC = 

level of concern. 

Absorption

Since no inhalation absorption data are available, toxicity by the inhalation route is considered to 

be equivalent to the estimated toxicity by the oral route of exposure. No acceptable dermal 

absorption study was submitted, therefore a default value of 100 percent dermal absorption factor 

was used to estimate dose. Given that aldicarb is handled only as a granular, it is unlikely that 

100 percent absorption would occur; however, the exact absorption factor could not be 

determined from the available toxicological studies.

Body Weight
Page 9 of 26

The standard body weight for the general population (80 kg) was used for all exposure scenarios 

for adults covered in this risk assessment since the endpoints selected were not developmental 

and/or fetal effects. 

4.0 Use Profile 

Aldicarb is a broad spectrum insecticide and is currently registered as a granular formulation that 

is only applied via soil incorporation (EPA Reg. #87895-1). It is registered for use on a number 

of agricultural crops via ground-based application equipment. Table 4.1 provides additional 

detail on the registered use sites.

The registered product is classified as a Restricted Use Pesticide (RUP) and may be purchased 

and used only by certified applicators or persons under their direct supervision. As an RUP the 

aldicarb product labels contain substantial protective measures to prevent worker exposure. 

Aldicarb handlers must use either:

 Engineering Controls (i.e., a closed loading system), or

 a minimum of coveralls over a long-sleeved shirt and long pants, chemical-resistant 

gloves made of any waterproof material, and chemical-resistant footwear plus socks. In 

addition, during loading, equipment cleaning or repair, or spill clean-up, handlers must 

wear protective eyewear (goggles or face shield), a chemical-resistant apron, and a 

NIOSH-approved respirator with a dust/mist filter with the MSHA/NIOSH approval 

number prefix TC-21C or any N, R, P or HE filter.

The available product label indicates that the product can be used generally once or twice per 

growing season (pre-plant or pre-plant plus early post-emergence), depending on the pest to be 

treated. The intended pests for the maximum application rates are generally nematodes, and the 

lesser rates for mites, thrips, mexican bean beetles, and other pests.

Table 4.1 provides a summary of the pests and directions per use for each target crop. 
Page 10 of 26

Table 4.1. Summary of Directions for Use of Aldicarb.

Applic. 

Equip.

Formulation 

[EPA Reg. No.] Applic. Rate (lb ai/A)

Max. No. 

Applic. per 

Season

Max. Seasonal 

Applic. Rate (lb 

ai/A)

PHI 

(days) Use Directions and Limitations

Dry Bean

Motorized 

Ground 

Equipment

15% ai granular

87895-1

2.1

[nematodes]

1

2.1 90

 Apply granules in seed furrow & immediately cover with soil 

by mechanical means.

 FOR USE ONLY IN: Colorado, Oregon, Washington, Idaho, 

& Michigan

1.05

[aphids]

1

0.75

[seedcorn maggot]

1

Sugar Beet

Motorized 

Ground 

Equipment

15% ai granular

87895-1

4.95

[nematodes] 1 at planting 

application &

2 postemergence 

applications 

4.2 in California 

4.95 in other 

states 

90

 Apply granules in a 4 to 6 inch band and immediately cover 

w/ soil by mechanical means.

 Plant seed into or above treated zone

 FOR USE ONLY IN: California, Colorado, Idaho, Montana, 

Nebraska, Oregon, Washington and Wyoming.

3

[leafminers

leafhoppers]  Drill granules 1 to 3 in. below seedline. Granules can be 

placed in seed furrow if rate does not exceed 1.05 lb ai/acre.

2.1

[aphids]

Cotton

Motorized 

Ground 

Equipment

15% ai granular

87895-1

1.05

[nematodes]

1 (at-plant)

1 (postemergence)

3.15

90

 Max single application rate

 Apply granules in the seed furrow and immediately cover with 

soil by mechanical means.

0.75

[aphids/thrips]

90  Apply granules in the seed furrow and immediately cover with 

soil by mechanical means.

2.1

[side dress 

applications]

90

 Max single rate for side dress applications

 Apply granules in the seed furrow and immediately cover with 

soil by mechanical means.

Peanut

Motorized 

Ground 

Equipment

15% ai granular

87895-1

1.5

(post-emergent 

rate; split 

application)

2.55 90

 Do not make more than one application per crop per year in 

states other than Alabama, Florida, Georgia, North Carolina, 

Oklahoma, Texas & Virginia.
Page 11 of 26

Table 4.1. Summary of Directions for Use of Aldicarb.

Applic. 

Equip.

Formulation 

[EPA Reg. No.] Applic. Rate (lb ai/A)

Max. No. 

Applic. per 

Season

Max. Seasonal 

Applic. Rate (lb 

ai/A)

PHI 

(days) Use Directions and Limitations

[nematodes /postpegging]

 Apply granules in seed furrow & immediately cover w/ soil by 

mechanical means.

 Post-emergence applications are permitted only in fields 

where overhead irrigation is available.

1.05

[nematodes/thrips]

At-planting

 Do not make more than one application per crop per year in 

states other than Alabama, Florida, Georgia, North Carolina, 

Oklahoma, Texas & Virginia.

 Apply granules in seed furrow & immediately cover w/ soil by 

mechanical means.

Sweet Potato

Motorized 

Ground 

Equipment

15% ai granular

87895-1

3

[nematodes/high rate]

Pre-plant or atplant 3 120

 For use only in Louisiana and Mississippi.

 Apply granules in a 12-in. band over open furrow or soil 

surface and cover immediately during bed forming by 

mechanically hilling up 8 to 10 inches.

1.5

[nematodes/lower 

rate]

Soybean

Motorized 

Ground 

Equipment

15% ai granular

87895-1

1.05

[mexican bean beetle 

/thrips]

1 application 

/per crop /per 

year

1.05

90

 FOR USE ONLY IN:

Georgia, North Carolina, South Carolina, & Virginia

 Apply granules in seed furrow and immediately cover with 

soil by mechanical means.

0.75

[nematodes /thrips]

0.75
Page 12 of 26

5.0 Residential Exposure and Risk Estimates

A quantitative residential assessment was not conducted because aldicarb is an RUP and there 

are no currently registered non-occupational (residential) uses. 

6.0 Non-Occupational Spray Drift Exposure and Risk Estimates

Off-target movement of pesticides can occur via many types of pathways and it is governed by a 

variety of factors. However, the aldicarb end use product is formulated as a granular and will not 

result in spray drift because of how it is applied (pre-plant/post-emergent soil incorporation). 

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

There is an available air monitoring study

5

conducted in California by the California Air 

Resources Board (CARB). The report presents the results of application air monitoring (in 

Fresno County) and ambient air monitoring (in Fresno and Kern Counties). 

Application site air monitoring (i.e., also known as field volatility) refers to the collection of air 

samples around the edges of a treated field during and after a pesticide application. Samples are 

generally collected for short intervals (e.g., < 8 hours), for at least the first day or two after 

application with subsequent samples increasing in duration. In this type of study, it is typically 

known when an application occurred, the equipment used for the application, and the application 

rate. Application site monitoring data represents an exposure to vapors at or near the field edge 

resulting from an application.

Ambient air monitoring typically is focused on characterizing the airborne pesticide levels within 

a localized airshed or community structure of some definition (e.g., city, township, or 

municipality). This type of monitoring effort also can be focused on capturing chronic 

background levels or other temporal characteristics of interest such as focusing on seasonal 

pesticide use patterns. Typically, samples are generally taken for 24 consecutive hours and 

collected at the same site over an extended period of time (e.g., several weeks or months). In 

contrast to application site air monitoring, information on the precise timing and location of 

pesticide applications are rarely collected in ambient air monitoring studies. However, this does 

not mean that an application did not occur near an ambient sampler during the monitoring period.

Two application studies were conducted in Fresno County; however, due to problems with the 

first study, which was associated with cotton planting, a second study was conducted which was 

associated with cotton “at first squaring.” First squaring refers to a process of manual weed 

control (tilling) during which the insecticide is applied to the cotton row berms. Of the twenty 

application samples collected during the first study, two were found to be detected (meaning 

results were below the limit of quantitation but equal to or above the limit of detection) and the

remaining 18 were less than the limit of detection (LOD) of 0.050 ug/sample. For the second 

 

5 Report for the Application and Ambient Air Monitoring of Aldicarb. California Environmental Protection Agency 

Air Resources Board. November 16, 1998. http://www.cdpr.ca.gov/docs/emon/pubs/tac/tacpdfs/aldicarb.pdf
Page 13 of 26

application study, all four background samples had results less than the LOD. Of the twenty-four 

application samples collected, all were found to be less than the LOD of 0.050 ug/sample.

Ambient monitoring was initially conducted during a three week period from March 24 to April 

11, 1997 in Fresno County. The monitoring was scheduled to coincide with cotton planting and 

the aldicarb samplers were collocated with samplers being used for an ambient phorate air 

monitoring study. No detectable levels of aldicarb were observed during the first three weeks of 

monitoring in Fresno County and so the remaining 3 weeks of monitoring was conducted in June 

in Kern County. Of the 60 ambient samples collected in Fresno County and the 55 collected in 

Kern County, all were found to be less than the LOD of 0.050 ug/sample.

8.0 Occupational Exposure and Risk Estimates

8.1 Occupational Handler Exposure/Risk Estimates

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

application process. HED 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 

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 exposure is expected from the proposed uses. 

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

occupational handler crop scenarios (and application rates) identified in Section 4.0. 

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.

Unit Exposures: It is the policy of HED to use the best available data to assess handler exposure. 

For this assessment, two main sources of data were used:

 The first source of data was a chemical-specific study (MRID 438525016) that collected 

occupational handler dermal and inhalation exposure data representative of the registered 

“low dust” formulation. A summary of the study data as collected is included in 

Appendix B. Additional details on the study description and specifics of the data can be 

found in a previous assessment (Memo, J. Dawson, D311821, 1/11/15). For scenarios 

representing open loading and open cab application of low dust corn cob granules, unit 

exposure data from the chemical-specific study were used. It should be noted that the 

study was conducted without handlers wearing a respirator; however, the currently 

registered label requires handlers wear a respirator. Therefore, the inhalation unit 

exposures were adjusted to account for current label PPE (i.e., filtering facepiece 

 

6 EPA MRID 43852501: Rosenheck, L., Schuster, L. (1995) Worker Loader and Applicator Exposure to Temik 15G. Study 

number 94388, Unpublished study prepared by ABC Laboratories, Pan-Ag Division; Rhone-Poulenc Ag Company.
Page 14 of 26

respirator) [i.e., an 80% assumed reduction from the inhalation unit exposure).

 The second source of data includes generic handler data. 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 Table”, which, along with additional information on HED 

policy on use of surrogate data, including descriptions of the various sources, can be 

found at the Agency website7. These data were used to assess scenarios representative of 

closed loading systems (engineering controls).

Area Treated or Amount Handled: 

Based on HED ExpoSAC Policy 9.1, Table 8.1.1 identifies the amount treated or handled per 

day per registered use site: 

Table 8.1.1 – Area Treated or Amount Handled.

Equipment Type Area Treated/Amount Handled Crop/Use Site

Groundboom Equipment

80 acres for typical-acreage field 

crops

 Sweet potatoes

200 acres for high acreage field 

crops

 Dry beans

 Sugar beets

 Cotton

 Peanuts (pre-plant/at-plant)

 Soybean

Exposure Duration: 

HED classifies exposures from 1 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 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). Therefore, this document includes an occupational exposure assessment 

consistent with the short- and intermediate-term exposure durations discussed above.

Personal Protective Equipment: Estimates of dermal and inhalation exposure were calculated 

for various levels of personal protective equipment (PPE). Results are presented for loaders and 

applicators based on the personal protective equipment identified on the label:

 Baseline, plus chemical-resistant gloves and coveralls with a PF5 respiratory protection 

device or

 Engineering controls (closed loading system or closed cab).

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.

 

7 http://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/occupational-pesticide-handler-exposure-data
Page 15 of 26

Combining Exposures/Risk Estimates:

Dermal and inhalation risk estimates were combined in this assessment, since the toxicological 

effects for these exposure routes were similar. Dermal and inhalation risk estimates were 

combined using the following formula:

Total MOE = Point of Departure (mg/kg/day) ÷ Combined dermal + inhalation dose (mg/kg/day)

Summary of Occupational Handler Non-Cancer Exposure and Risk Estimates

Occupational handler risk estimates are presented using both HED’s standard occupational 

exposure methodology and the available chemical-/scenario-specific handler data, where 

available. 

Table 8.1.2 shows loader and applicator risk estimates assuming label-specified PPE [open 

loading scenarios] using the available chemical-specific handler data (occupational handlers with 

PPE). Table 8.1.3 shows loader and applicator risk estimates assuming engineering controls (i.e. 

closed loading systems) are used (based on the PHED surrogate unit exposure data).

Where risk concerns exist, the combined risk estimates are driven by dermal exposure. It should 

be noted that an assumption of 100% dermal absorption was used in the dermal exposure/risk 

calculations since an acceptable dermal absorption study was not submitted. Given that the 

registered product is a granular formulation, it is unlikely that 100% absorption would occur.

The following risk estimates of concern were identified (and are noted in bold in the tables):

Open Mixing/Loading and Open-cab Application Using Label-specified PPE:

 Mixer/loader scenarios (using chemical-specific data):

o Sugar beets at 3 & 4.95 lbs ai/A (MOEs = 7.4 and 5, respectively)

Closed Mixing/Loading and Closed-cab Application (i.e., engineering controls):

 Mixer/loader scenarios (using surrogate exposure data):

o All scenarios (total MOE ranges from 0.12 to 0.99 based on a LOC of 10)

 Applicator scenarios (using surrogate exposure data):

o All scenarios (total MOEs ranges from <1 to 3.9 based on a LOC of 10)
Page 16 of 26

Table 8.1.2. Occupational Handler Non-Cancer Exposure and Risk Estimates for Aldicarb. 

Open Pour/Open Cab Application Using Label-Required PPE (Double layer of clothing and PF5 Respirator) Using Chemical-Specific Data.

Crop or Target

Dermal Unit 

Exposure 

(μg/lb ai)1

[Level of PPE]

Inhalation Unit 

Exposure 

(μg/lb ai)1

[Level of PPE]

Maximum 

Application 

Rate (lb ai/A)2

Area 

Treated 

Daily 

(Acres)3

Dermal Inhalation Total

Dose 

(mg/kg/day)4

MOE

(LOC = 10)5

Dose 

(mg/kg/day)6

MOE

(LOC = 10)7

MOE

(LOC = 10)8

Mixer/Loader (Load Granules – tractor drawn spreader)

Sweet potato [e.g., nematodes]

0.22

[DL/G]

0.014

[PF5]

3

80

0.00066 20 0.000042 310 19

1.5 0.00033 39 0.000021 620 37

Sugar beet [e.g. nematodes] 4.95

200

0.00273 4.8 0.000174 75 4.5

Sugar beet [leafminers/leafhoppers] 3 0.00165 7.9 0.000105 120 7.4

Dry bean [nematodes]; Sugar beet 

[aphids]; Cotton [side-dress 

applications]

2.1 0.00116 11 0.0000735 180 10

Peanut [nematodes /post-pegging] 1.5 0.000825 16 0.0000525 250 15

Dry bean [aphids]; Cotton 

[nematodes]; Peanuts 

[nematodes/thrips]; Soybean 

[mexican bean beetle/thrips]

1.05 0.000578 22 0.0000368 350 21

Dry bean [seedcorn maggot]; Cotton 

[aphids/thrips]; Soybean 

[nematodes/thrips]

0.75 0.000413 31 0.0000263 490 29

Applicator (granules – tractor-drawn spreader)

Sweet potato [e.g., nematodes]

0.089

[DL/G]

0.0026

[PF5]

3

80

0.000268 49 0.0000078 1700 48

1.5 0.000134 97 0.0000039 3300 94

Sugar beet [e.g. nematodes] 4.95

200

0.0011 12 0.0000321 400 12

Sugar beet [leafminers/leafhoppers] 3 0.000668 19 0.0000195 670 18

Dry bean [nematodes]; Sugar beet 

[aphids]; Cotton [side-dress 

applications]

2.1 0.000468 28 0.0000136 960 27

Peanut [nematodes /post-pegging] 1.5 0.000334 39 0.00000975 1300 38

Dry bean [aphids]; Cotton 

[nematodes]; Peanuts 

[nematodes/thrips]; Soybean 

1.05 0.000234 56 0.00000683 1900 54
Page 17 of 26

Table 8.1.2. Occupational Handler Non-Cancer Exposure and Risk Estimates for Aldicarb. 

Open Pour/Open Cab Application Using Label-Required PPE (Double layer of clothing and PF5 Respirator) Using Chemical-Specific Data.

Crop or Target

Dermal Unit 

Exposure 

(μg/lb ai)1

[Level of PPE]

Inhalation Unit 

Exposure 

(μg/lb ai)1

[Level of PPE]

Maximum 

Application 

Rate (lb ai/A)2

Area 

Treated 

Daily 

(Acres)3

Dermal Inhalation Total

Dose 

(mg/kg/day)4

MOE

(LOC = 10)5

Dose 

(mg/kg/day)6

MOE

(LOC = 10)7

MOE

(LOC = 10)8

[mexican bean beetle/thrips]

Dry bean [seedcorn maggot]; Cotton 

[aphids/thrips]; Soybean 

[nematodes/thrips]

0.75 0.000168 77 0.00000488 2700 75

1 Based on MRID 43852501; The study inhalation unit exposure (0.07 ug/lb ai) representative of baseline protection (i.e. no respirator) was adjusted to represent use of a PF5 respirator (i.e., 80% 

reduction in exposure). PF5 = a NIOSH-approved respirator with a dust-mist filter with MSHA/NIOSH approval number prefix TC-21 or any N, R, P or HE filter. 

2 Based on registered label (Reg. No. 87895-00001).

3 Exposure Science Advisory Council Policy #9.1.

4 Dermal Dose = Dermal Unit Exposure (μg/lb ai) × Conversion Factor (0.001 mg/μg) × Application Rate (lb ai/acre) × Area Treated (A/day) × DAF (100%) ÷ BW (80 kg).

5 Dermal MOE = Dermal BMDL10 (0.013 mg/kg/day) ÷ Dermal Dose (mg/kg/day).

6 Inhalation Dose = Inhalation Unit Exposure (μg/lb ai) × Conversion Factor (0.001 mg/μg) × Application Rate (lb ai/acre) × Area Treated (A/day) ÷ BW (80 kg).

7 Inhalation MOE = Inhalation BMDL10 (0.013 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

8 Total MOE = BMDL10 (0.013 mg/kg/day) ÷ [Dermal Dose + Inhalation Dose]

Table 8.1.3. Occupational Handler Non-Cancer Exposure and Risk Estimates for Aldicarb. 

Engineering Controls.

Crop or Target

Dermal Unit 

Exposure 

(μg/lb ai)1

[Level of PPE]

Inhalation Unit 

Exposure 

(μg/lb ai)1

[Level of PPE]

Maximum 

Application 

Rate (lb ai/A)2

Area Treated 

Daily 

(Acres)3

Dermal Inhalation Total

Dose 

(mg/kg/day)4

MOE 

(LOC = 10)5

Dose 

(mg/kg/day)6

MOE

(LOC = 10)7

MOE

(LOC = 10)8

Loader (Load Granules – tractor drawn spreader)

Sweet potato [e.g., nematodes]

8.6

[EC]

0.083

[EC]

3

80

0.0258 0.5 0.000249 52 0.5

1.5 0.0129 1 0.000125 100 0.99

Sugar beet [e.g. nematodes] 4.95

200

0.106 0.12 0.00103 13 0.12

Sugar beet [leafminers/leafhoppers] 3 0.0645 0.2 0.000623 21 0.2

Dry bean [nematodes]; Sugar beet 

[aphids]; Cotton [side-dress 

applications]

2.1 0.0451 0.29 0.000436 30 0.29

Peanut [nematodes /post-pegging] 1.5 0.0323 0.4 0.000311 42 0.4

Dry bean [aphids]; Cotton 

[nematodes]; Peanuts 

[nematodes/thrips]; Soybean 

1.05 0.0226 0.58 0.000218 60 0.57
Page 18 of 26

Table 8.1.3. Occupational Handler Non-Cancer Exposure and Risk Estimates for Aldicarb. 

Engineering Controls.

Crop or Target

Dermal Unit 

Exposure 

(μg/lb ai)1

[Level of PPE]

Inhalation Unit 

Exposure 

(μg/lb ai)1

[Level of PPE]

Maximum 

Application 

Rate (lb ai/A)2

Area Treated 

Daily 

(Acres)3

Dermal Inhalation Total

Dose 

(mg/kg/day)4

MOE 

(LOC = 10)5

Dose 

(mg/kg/day)6

MOE

(LOC = 10)7

MOE

(LOC = 10)8

[mexican bean beetle/thrips]

Dry bean [seedcorn maggot]; Cotton 

[aphids/thrips]; Soybean 

[nematodes/thrips]

0.75 0.0161 0.81 0.000156 83 0.8

Applicator

Sweet potato [e.g., nematodes]

2.0

[EC]

0.22

[EC]

3

80

0.006 2.2 0.00066 20 2

1.5 0.003 4.3 0.00033 39 3.9

Sugar beet [e.g. nematodes] 4.95

200

0.0248 0.52 0.00273 4.8 0.47

Sugar beet [leafminers/leafhoppers] 3 0.015 0.87 0.00165 7.9 0.78

Dry bean [nematodes]; Sugar beet 

[aphids]; Cotton [side-dress 

applications]

2.1 0.0105 1.2 0.00116 11 1.1

Peanut [nematodes /post-pegging] 1.5 0.0075 1.7 0.000825 16 1.5

Dry bean [aphids]; Cotton 

[nematodes]; Peanuts 

[nematodes/thrips]; Soybean 

[mexican bean beetle/thrips]

1.05 0.00525 2.5 0.000578 22 2.2

Dry bean [seedcorn maggot]; Cotton 

[aphids/thrips]; Soybean 

[nematodes/thrips]

0.75 0.00375 3.5 0.000413 31 3.1

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (September, 2015) as noted; Level of mitigation: Eng. Controls.

2 Based on registered label (Reg. No. 87895-00001).

3 Exposure Science Advisory Council Policy #9.1.

4 Dermal Dose = Dermal Unit Exposure (μg/lb ai) × Conversion Factor (0.001 mg/μg) × Application Rate (lb ai/acre) × Area Treated (A/day) × DAF (100%) ÷ BW (80 kg).

5 Dermal MOE = Dermal BMDL10 (0.013 mg/kg/day) ÷ Dermal Dose (mg/kg/day).

6 Inhalation Dose = Inhalation Unit Exposure (μg/lb ai) × Conversion Factor (0.001 mg/μg) × Application Rate (lb ai/acre) × Area Treated (A/day) ÷ BW (80 kg).

7 Inhalation MOE = Inhalation BMDL10 (0.013 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

8 Total MOE = BMDL10 (0.013 mg/kg/day) ÷ [Dermal Dose + Inhalation Dose]
Page 19 of 26

Handler Risk Characterization:

The occupational handler scenarios assessed represent low dust formulations, while the surrogate

data used to assess engineering controls are from studies using clay granules which are known to 

be more friable (i.e., more dusty) than engineered low dust formulations such as used for 

aldicarb. The low-dust vinyl-coated scenarios associated with the closed loading scenario have 

lower exposure potential than the clay-based substrate surrogate in the surrogate engineering 

control unit exposures.

HED notes that qualitatively the occupational exposure using engineering controls for any given 

handling or loading scenario is lower than the available chemical-specific handler data 

(occupational handlers with PPE). While the available chemical-specific study is representative 

of the low-dust formulation, it cannot be used to estimate exposure from the use of engineering 

controls (i.e., closed loading and closed cab applications). HED acknowledges that the unit 

exposures for the use of engineering controls with the low-dust formulation should be less than 

those identified in the study for use of open pour/open cab application. It is noted that based on 

the surrogate unit exposure guide, closed loading/closed cab systems often provide up to 90% 

reduction in exposure.

9.2 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 activities, can greatly reduce the potential for post-application exposure.

9.2.1 Occupational Post-application Inhalation Exposure/Risk Estimates

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;D=EPA-HQ-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-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 aldicarb. 
Page 20 of 26

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 post-application inhalation exposure into the agency's risk assessments.

9.2.2 Occupational Post-application Dermal Exposure/Risk Estimates

A quantitative post-application assessment has not been conducted for aldicarb because 

aldicarb is soil incorporated and there is limited potential for worker dermal exposure to soil 

incorporated pesticides. 

In accordance with 40 CFR 158, dislodgeable foliar residue (DFR) data are required for all 

occupational (e.g., crop, nursery, greenhouse use sites) or residential (e.g., ornamental and 

vegetable gardens, pick your own farms, retail tree farms) uses that could result in postapplication exposure to foliage. In the case of aldicarb, there are no currently labeled uses that 

would result in foliar residue; therefore, no DFR data are required at this time. In the case that 

the registered use pattern changes, HED would reevaluate the need for a DFR study, depending 

on the proposed label change.

The REI specified on the existing labels [48 hours] is based on the acute toxicity of aldicarb. 

Aldicarb is classified as Toxicity Category I via the dermal, oral, and inhalation routes of 

exposure. Due to severe effects (death) following corneal and dermal dosing, dermal and eye 

irritation studies were waived in the acute toxicity database. Because of the limited worker 

exposure profile (soil-incorporation), the REI on the labels is adequate to protect for worker 

exposure. Therefore, the [156 subpart K] Worker Protection Statement interim REI of 48 hours 

is adequate to protect agricultural workers from post-application exposures to aldicarb. 
Page 21 of 26

Appendix A. Summary of Occupational and Residential Non-cancer Algorithms

Occupational Non-cancer Handler Algorithms

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

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

where:

E = exposure (mg ai/day),

UE = unit exposure (μg ai/lb ai),

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

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

The daily doses are calculated using the following formula:

ADD= 

E * AF

BW

where:

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

E = exposure (mg ai/day),

AF = absorption factor (dermal and/or inhalation), and

BW = 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 dermal and inhalation dose received by occupational 

handlers are compared to the appropriate POD (i.e., NOAEL) to assess the risk to occupational 

handlers for each exposure route. All MOE values are calculated using the following formula:

MOE= 

POD

ADD

where:

MOE = margin of exposure: value used by HED to represent risk estimates (unitless),

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

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

Occupational Non-cancer Post-application Algorithms
Page 22 of 26

Potential daily exposures for occupational post-application workers are calculated using the 

following formulas:

DFRt=AR * F* (1-D)t* (4.54E8

ug

lb) * (2.47E-8

A

cm2

)

where:

DFRt = dislodgeable foliage residue on day "t" (μg/cm2),

AR = application rate (lb ai/acre),

F = fraction of ai retained on foliage or 25% (unitless),

D = fraction of residue that dissipates daily or 10% (unitless), and

t = number of days after application day (days).

E=TC * DFR t* ET * 0.001

mg

ug

where:

E = exposure (mg ai/day),

TC = transfer coefficient (cm2/hr),

DFRt = dislodgeable foliar residue on day “t” (μg/cm2), and

ET = exposure time (hours/day).

The daily doses are calculated using the following formula:

ADD= 

E * AF

BW

where:

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

E = exposure (mg ai/day),

AF = absorption factor (dermal and/or inhalation), and

BW = body weight (kg).

Margin of Exposure: Non-cancer risk estimates for each 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 dermal dose received by occupational post-application workers is compared to the 

appropriate POD (i.e., NOAEL) to assess the risk to occupational post-application workers. All 

MOE values are calculated using the following formula:

MOE= 

POD

ADD

where:
Page 23 of 26

MOE = margin of exposure: value used by HED to represent risk estimates (unitless),

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

ADD = average daily dose absorbed in a given scenario (mg ai/kg/day).
Page 24 of 26

Appendix B. Summary of Available Occupational Handler Exposure Data

One chemical-specific study was submitted in support of the reregistration of aldicarb, and was 

judged to be appropriate for use in occupational exposure/risk assessments. These data have not 

been integrated with PHED for this assessment because the granules used are vinyl coated 

formulation (i.e., a “low dust formulation”) which is likely to lead to differences in exposure. The 

study can be identified by the following information:

EPA MRID 43852501: Rosenheck, L., Schuster, L. (1995) Worker Loader and Applicator 

Exposure to Temik 15G. Study number 94388, Unpublished study prepared by ABC Laboratories, 

Pan-Ag Division; Rhone-Poulenc Ag Company.

This study quantified exposure to aldicarb for workers loading and applying Temik 15G (EPA 

Reg. No. 264-330) at the maximum rate of 6 lb ai/acre in pecan groves using shank injection. 

Dermal and inhalation exposure levels to aldicarb and its two principal by-products, aldicarb 

sulfoxide and aldicarb sulfone, were measured. Five replicates of the loading and application of 

Temik 15G were monitored at each of the three locations for a total of 15 loading and 15 

application replicates (mixer/loaders were monitored separately from the applicators). The study 

was conducted in three locations; Raymond, Mississippi; Brownwood, Texas; and Albany, 

Georgia.

The use of a modified Tye seeder in the three different locations was consistent with commercial 

agricultural practice (i.e., recommended equipment for aldicarb applications). The test subjects 

also wore protective clothing that met U.S. EPA Worker Protection Standards, consisting of nitrile 

rubber gloves, rubber boots, goggles, hard hat, a dust filtering respirator and a chemical resistant 

apron (loader only) over short-sleeved shirt, short pants and coveralls. The duration of each 

loading replicate was approximately 4 hours, and during this time the modified seeder was loaded 

and emptied twice (once at the start and again after about 2 hours). The application replicates were 

monitored using open cab tractors over a period of approximately 4 hours. The loaders handled a 

range of 900 lb to 1485 lb of Temik 15G (135 lb to 223 lb ai) per replicate. The average application 

rate was approximately 40 lb product per acre (6 lb ai/A, the maximum rate). Aldicarb was 

packaged in 45 pound bags and open cab tractors were used.

Dermal exposures were monitored using whole-body dosimetry (long underwear, later sectioned 

into arms, chest, back, and lower body), handwashes and facial and neck swipes. The long 

underwear (100% cotton) was worn under short pants and a short sleeved shirt. Hand exposure 

was monitored by having each test subject remove gloves and wash both hands twice in detergent 

solution (0.01% v/v Aerosol OT 75). Face and neck exposures were monitored by wiping the face 

and neck with 10 percent cotton gauze pads wet with the detergent solution. Inhalation exposures 

were monitored using a XAD2 resin tube, polyurethane foam, and glass fiber filter to collect both 

vapor and particulate matter. The tubes were attached to a personal air pump with a flow rate of 

approximately 1.5 liters/minute. The limits of quantification (LOQs) for each matrix are presented 

in Table 1.
Page 25 of 26

Table 3: Limits of Quantification and Detection in Study

Area LOQ 

(μg/ml)

<LOQ:Replicates LOD 

(μg/ml)

Non-detects:Replicates

Loader Applicator Loader Applicator

Dermal:

Arm, chest, back

Lower Body

Handwash

Facial Wipe

1.00

2.00

1.00

0.10

21:45

0:15

1:15

4:15

25:45

3:15

2:15

2:15

0.40

0.67

0.30

0.01

6:45

0:15

0:15

0:15

6:45

2:15

2:15

0:15

Inhalation:

OVS Tube 0.05 1:15 6:15 0.020 0:15 1:15

a LOD = Minimum Standard Concentration Tested (0.01μg/ml) * Dilution Factor.

Arm, chest, back Dilution Factor = 40

Lower Body Dilution Factor = 67

Handwash Dilution Factor = 30

Facial Wipe Dilution Factor = 1

OVS Tube Dilution Factor = 1

Note: For Loaders: Aldicarb 38 of 90 samples were <LOQ, 11 of 90 samples were <LOD, Aldicarb sulfone 79 of 90 samples 

were < LOQ, 47 of 90 samples were <LOD and aldicarb sulfoxide 56 of 90 samples were < LOQ, 20 of 90 samples were 

<LOD.

For Applicators: Aldicarb 56 of 90 samples were <LOQ, 15 of 90 samples were <LOD, Aldicarb sulfone 83 of 90 samples 

were < LOQ, 55 of 90 samples were <LOD and aldicarb sulfoxide 79 of 90 samples were < LOQ, 27 of 90 samples were 

<LOD.

For detected peaks whose values fell below the LOQ but above the limit of detection (LOD), 

results were reported as 50 percent of the LOQ. This is within current Agency guidelines. 

However, when the results fell below the LOD (i.e. "no peak detected"), the study reported the 

result as only 10 percent of the LOQ. The study did not mention the LOD value used for this 

interpretation.

In place of the 10 percent LOQ value given non-detects, 50 percent LOD was used in the exposure 

calculations. The LOD for each matrix was calculated based on the lowest quantifiable level in 

the calibration curve as presented in the analytical methods section of the study. 

The study was conducted in accordance with most of 875 Guidelines Group A, Applicator 

Monitoring Exposure Test Guidelines. Field recovery for aldicarb, aldicarb sulfoxide, and aldicarb 

sulfone are presented in Table 2. 

Table 2: Field Fortification Recoveries.

Matrix

Field Percent Recovery (CV %)*

n

Aldicarb Aldicarb Sulfoxide Aldicarb Sulfone

Inhalation Tube 77 (4) NA NA 8

Handwash 78 (13) 75 (5) 90 (11) 8

Facial Swab 84 (7) 92 (5) 92 (4) 8

Body Dosimeter 83 (7) 81 (5) 91 (3) 8

* CV = standard deviation  mean

Laboratory recovery for aldicarb, aldicarb sulfoxide and aldicarb sulfone is presented in Table 3. 

Storage stability data were acceptable. Control samples had residues less than the LOQ and the 

recoveries were within the EPA acceptable range of 70-120%.
Page 26 of 26

Table 3: Laboratory Recoveries.

Matrix Laboratory Percent Recovery (CV %, n)

Aldicarb Aldicarb Sulfoxide Aldicarb Sulfone

Inhalation Tube 81 (16, n=24) 84 (12, n=24) 83 (10, n=24)

Handwash 93 (7.6, n=17) 83 (9.7, n=17) 98 (7.7, n=17)

Facial Swab 90 (13, n=13) 90 (9.7, n=13) 92 (11, n=13)

Body Dosimeter 83 (16, n= 21) 89 (12, n=21) 96 (10, n=21)

The values used in risk assessment were adjusted for field recovery (results below 90 percent 

increased to 100 percent) and normalized to mg (μg for inhalation) of aldicarb exposure per lb of 

aldicarb handled (incorporating the 50 percent LOD value for non-detects and 50 percent LOQ for 

values below the LOQ). The values calculated are presented in Table 4.

Table 4: Results from Aldicarb Pecan Loader and Applicator Study.

Task Dermal (mg ai exposure/ lb ai handled) Inhalation (μg ai exposure/ lb ai handled)

Arithmetic 

Mean*

Geometric 

Mean

Median Arithmetic 

Mean*

Geometric 

Mean

Median

Loader 0.00022 0.00019 0.00017 0.070 0.025 0.022

Applicator 0.000089 0.000081 0.000078 0.013 0.0044 0.0044

* Used as the unit exposure for occupational risk estimation