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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

Date: November 9, 2015

Subject: Boric Acid/Sodium Salts of Boric Acid. Occupational and Residential Exposure 

and Risk Assessment for Registration Review.

PC Code: 011101, 011102, 011103, 011104, 011107, 

011110, 011111, 011112, 011002

DP Barcode: D428582, D320890, D320888, D320728

Decision Number: 488334,359976,359975,359928 Registration Number: N/A

Petition Number: NA Regulatory Action: Registration Review

Risk Assessment Type: NA Case Number: 0024

TXR Number: NA CAS Number: 10043-35-3, 1303-96-4, 1130-12-4, 

12179-04-3, 1330-43-4, 12008-41-2, 15293-77-3, 1303-

86-2

MRID Numbers: 46852202, 47579901, 47579902, 

46971101

40CFR: §180.1121 (Active Ingredient); §180.920 (Inert 

Ingredient)

From: Matthew Crowley, Biologist

Risk Assessment Branch 2 (RAB2)

Health Effects Division (HED; 7509P)

Through: Christina Swartz, Branch Chief

Risk Assessment Branch 2 (RAB2)

Health Effects Division (HED; 7509P)

and

Kelly O’Rourke, Reviewer

James-S Miller, Reviewer

Exposure Science Advisory Committee (ExpoSAC) / HED

To: Moana Appleyard, Chemical Review Manager

Risk Management and Implementation Branch 5 (RMIB5)

Pesticide Re-evaluation Division (PRD)

As part of Registration Review, the Pesticide Re-evaluation Division (PRD) of EPA’s Office of 

Pesticide Programs (OPP) has requested that the Health Effects Division (HED) evaluate the 

hazard and exposure data and conduct occupational and residential exposure assessments, as 

needed, to estimate the risk to human health that will result from the currently registered uses of 

pesticides. This memorandum serves as HED’s Registration Review assessment of the 
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occupational and residential handler and post-application exposure and risk from the currently

registered uses of boric acid and its sodium salts. 

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

Handler Exposure Task Force (AHETF) database; the Outdoor Residential Exposure Task Force

(ORETF) database; the Residential SOPs (Lawns/Turf, Indoor Environments); and other 

registrant-submitted exposure studies (MRIDs 44339801, 45250702, 45333401, 44439901, 

45519601, 45167201, 43600102). 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-SEP-2015.
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Table of Contents

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

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

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

2.2 Label Recommendations.................................................................................................. 7

2.3 Data Deficiencies and Requirements ............................................................................... 7

3.0 Hazard Characterization...................................................................................................... 7

4.0 Exposure and Use Profile.................................................................................................. 11

5.0 Residential Exposure and Risk Estimates......................................................................... 16

5.1 Residential Handler Exposure/Risk Estimates............................................................... 17

5.2 Residential Post-application Exposure/Risk Estimates ...................................................... 21

5.3 Residential Risk Estimates for Use in Aggregate Assessment.......................................... 27

6.0 Non-Occupational Spray Drift Exposure and Risk Estimates.......................................... 28

7.0 Non-Occupational Bystander Post-Application Inhalation Exposure and Risk Estimates29

8.0 Occupational Exposure and Risk Estimates ..................................................................... 30

8.1 Occupational Handler Exposure/Risk Estimates............................................................ 30

8.2 Occupational Post-application Exposure/Risk Estimates .............................................. 41

8.2.1 Occupational Post-application Inhalation Exposure/Risk Estimates...................... 41

8.2.2 Occupational Post-application Dermal Exposure/Risk Estimates.......................... 41

Appendix A. Summary of Residential and Occupational Non-cancer Algorithms..................... 43
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1.0 Executive Summary

Boric acid [H3BO3] and its sodium salts (sodium tetraborate decahydrate, sodium tetraborate 

pentahydrate, sodium tetraborate anhydrous, disodium octaborate tetrahydrate, disodium 

octaborate anhydrous and sodium metaborate) are active ingredients in a wide variety of 

pesticides including insecticides, acaricides, herbicides, algaecides, fungicides and wood 

preservatives. This document assesses occupational and residential exposures and risk estimates 

from the registered conventional uses of boric acid and its sodium salts required during 

Registration Review. Exposure and risk estimates for antimicrobial uses of boric acid and its 

sodium salts (e.g., wood preservatives, swimming pools, etc.) are addressed in a separate 

assessment.

For purposes of risk assessment, exposure and toxicity are expressed in terms of boron 

equivalents, with molecular weight conversions to boron from boric acid or a borate sodium salt 

accordingly. 

Use and Exposure Profile

There are numerous pesticide products containing boric acid or its sodium salts as the active 

ingredient used in residential, commercial, and agricultural settings. Products are both liquid and 

solid formulations ranging from < 1% to 100% active ingredient. Products used in residential 

settings (e.g., dusts in homes, crack and crevice sprays, recreational parks), 

commercial/industrial areas (e.g., food handling establishments, airport runways, sewers, 

transport vehicles) and agricultural facilities (e.g., poultry houses) are applied via hand dispersal, 

handheld equipment and by vehicles. Products used on agricultural crops are applied via 

handheld sprays or by vehicles; chemigation and aerial applications are prohibited.

Based on the registered use pattern for boric acid/sodium salts, dermal and inhalation exposures 

are anticipated for both occupational and residential handlers (mixer/loaders, applicators, etc.). 

In addition, post-application exposures are also possible, including dermal exposures to re-entry 

field workers, and dermal and incidental oral exposures to children playing on treated grass. 

Additionally, dermal exposure to adults and children and incidental oral exposure to children via 

spray drift on to residential areas resulting from crop applications are expected.

Hazard Profile and Dose Response 

The toxicity database has been updated since previous assessments and is considered complete 

for the purposes of human health risk assessment.

Boric acid/borate salts generally show low acute lethality by all routes (Toxicity Categories III or 

IV). Acute dermal and eye irritation potential vary among the different compounds. For 

example, sodium tetraborate decahydrate is Category I for eye irritation and IV for skin irritation, 

while boric acid is Category III for both.

For short-/intermediate-term inhalation and incidental oral exposure, a No Observed Adverse 

Effect Level (NOAEL) of 8.8 mg/kg bw/day was selected based on hematological and testicular 
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effects observed in both a subchronic and chronic dog feeding study. All values are expressed in 

terms of boron. 

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

covered in this risk assessment since the endpoints selected were not developmental and/or fetal 

effects. For assessment of incidental oral exposures to children a body weight of 11 kg was 

used. 

Dermal absorption data in humans indicates negligible absorption (estimated at less than 1%) 

and is consistent with published reports in laboratory animals showing low or no absorption of 

boric acid or borate salts. Adjustment of the no observed adverse effect level (NOAEL) from the 

most sensitive oral doses for absorption of 1% would yield a dermal dose approaching the limit 

dose (1000 mg/kg bw/day). Therefore, though dermal exposure is possible, due to the very 

limited absorption of boric acid and its sodium salts, dermal toxicity was not identified and a 

point of departure was not selected. 

Inhalation and incidental oral risk estimates are combined where applicable due to use of the 

same toxicological endpoint. For both exposure scenarios, uncertainty factors (UFs) of 10x for 

interspecies (UFA), 10x for intraspecies (UFH) variation, and 1x for the Food Quality Protection 

Act (FQPA) safety factor (total UF of 100x) were used, thus characterization of risk estimates, in 

the form of Margins of Exposure (MOEs) are based on a level of 100. 

Boric acid/sodium borate salts are classified as “Not Likely to be Carcinogenic to Humans.” 

A quantitative cancer risk assessment is not required.

Residential Exposure and Risk

Many products, both applied as liquid sprays/solutions and as solids (dusts or granules), are used 

in residential settings. Dermal and inhalation exposures are possible during application and 

dermal, inhalation, and post-application incidental oral exposures are possible following 

applications.

Only post-application incidental oral risk estimates were of concern for broadcast spray 

treatments to carpets. All other handler and post-application risk estimates were not of concern.

The recommended scenario for the adult aggregate assessment is inhalation exposure during 

applications of dusts/powders to indoor residential areas via a shaker can. The recommended 

residential exposures for use in a children 1<2 years old aggregate assessment reflects the 

combined exposures from post-application inhalation and hand-to-mouth exposures following 

general indoor liquid applications to hard floors.

Spray drift

A quantitative non-occupational spray drift assessment was not conducted as the direct spray use 

on home lawns results in higher exposures than those resulting from spray drift on residential 
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areas resulting from agricultural uses. No risks of concern were identified resulting from the 

direct spray lawn use. 

 

Occupational Exposure and Risk

Occupational risk estimates are based on inhalation exposures only due to the lack of toxicity via 

the dermal route. Occupational inhalation handler risk estimates were of concern for a number 

of scenarios, requiring respiratory protection to mitigate risks. In a few cases, standard 

respiratory protection measures do not appear to be successful in mitigating inhalation risk 

estimates of concern.

Labels vary considerably with respect to requirements for work attire and personal protective 

equipment (PPE) and restricted entry intervals (REIs). Label corrections/revisions should be 

consistently made to default to end-use product and/or technical grade active ingredient acute 

(ocular, dermal, oral, and inhalation) toxicity requirements. Additional PPE, such as respiratory 

protection, beyond end-use product acute toxicity requirements, should be considered as 

described in the context of any risks of concern identified in this assessment.

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 

the Pesticide Handlers Exposure Database Version 1.1 (PHED 1.1); the Agricultural Handler 

Exposure Task Force (AHETF) database; the Outdoor Residential Exposure Task Force

(ORETF) database; the Residential SOPs (Lawns/Turf, Indoor Environments); and other 

registrant-submitted exposure studies (MRIDs 44339801, 45250702, 45333401, 44439901, 

45519601, 45167201, 43600102) 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 

website1. 

2.0 Risk Assessment Conclusions and Recommendations

2.1 Summary of Risk Estimates

 As no systemic dermal toxicity was identified, occupational and residential dermal 

exposure/risk assessment were not conducted. However, label requirements based on 

acute dermal toxicity categories for the active ingredients as well as the end use products 

should be evaluated and considered for label revisions. 

 Residential handler inhalation risk estimates were not of concern.

 Post-application residential incidental oral risk estimates were of concern for broadcast 

spray treatments to carpets (MOEs < 100). As a result, post-application combined 

 

1 http://www.epa.gov/pesticides/science/handler-exposure-data.html and 

http://www.epa.gov/pesticides/science/post-app-exposure-data.html
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inhalation and incidental oral risk estimates were also of concern for spray treatments to 

carpets (MOEs < 100). Post-application inhalation risk estimates alone were not of 

concern.

 Occupational handler inhalation risk estimates were of concern for a number of scenarios, 

requiring respiratory protection to mitigate risks. In a few cases, standard respiratory 

protection measures do not appear to be successful in mitigating inhalation risk estimates 

of concern.

2.2 Label Recommendations 

Labels vary considerably with respect to requirements for work attire and personal protective 

equipment (PPE). For example, some labels do not specify any requirements for work attire, 

while others require respirators and coveralls over long-sleeve shirt and long pants. Similarly, 

restricted entry intervals (REIs) also vary considerably across labels (e.g., 4 hours versus 48 

hours).

Thus, label corrections/revisions should be consistently made to default to end-use product 

and/or technical grade active ingredient acute (ocular, dermal, oral, and inhalation) toxicity 

requirements. These requirements may vary since each borate sodium salt might have a different 

acute toxicity profile, in addition to the potential presence of other active ingredients in a 

product. In particular, 4 hour REIs should be evaluated in the context of Pesticide Registration 

(PR) Notice 95-3 (see Section 8.2.2). Due to sodium tetraborate decahydrate being acute toxicity 

category I for eye irritation, the 4 hour may not be appropriate for this active ingredient class.

Additional PPE, such as respiratory protection, beyond end-use product acute toxicity 

requirements, should be considered as described in the context of any risks of concern identified 

in this assessment.

2.3 Data Deficiencies and Requirements

The exposure database is sufficient to support Registration Review of boric acid and its sodium 

salts and any data requirements have been satisfied. 

3.0 Hazard Characterization

Acute Toxicity

Boric acid/borate salts generally show low acute toxicity by oral and dermal routes (Toxicity 

Categories III or IV). Boric acid is Category III for acute inhalation, due to limitations in 

generating test atmosphere concentrations and not mortality (none observed). Dermal and eye 

acute irritation potential vary. Sodium tetraborate decahydrate (borax) is Category I for eye 

irritation and IV for skin irritation, while boric acid is Category III for both.

Table 3.1.a. Acute Toxicity Profile - Boric Acid 

Guideline No. Study Type MRID(s) Results Toxicity Category
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870.1100 Acute oral rat 00006719 LD50 males = 3450 mg/kg 

females = 4080 mg/kg 

III

870.1100 Acute oral beagle dog 00064208 LD50 > 631 mg/kg III

870.1200 Acute dermal rabbit 00106011 LD50 >2 g/kg III

870.1300 Acute inhalation rat 43500701 LC50>2.03 mg/L (no 

deaths)1

III

870.2400 Acute eye irritation rabbit 00064209 Conjunctival irritation 

clearing by Day 4

III

870.2500 Acute dermal irritation rabbit 00106011 Primary irritation score = 

0.1; 1/6 erythema at 72 

hrs

III

1 exposure levels were limited by inability to produce higher test atmosphere concentrations

Table 3.1.b. Acute Toxicity Profile - Sodium tetraborate decahydrate (Borax) 

Guideline No. Study Type MRID(s) Results Toxicity Category

870.1100 Acute oral rat 40692303 LD50 males = 4550 mg/kg 

females = 4980 mg/kg 

III

870.1100 Acute oral dog 40692304 LD50 > 974 mg/kg III

870.1200 Acute dermal rabbit 43553201 LD50 > 2000 mg/kg III

870.1300 Acute inhalation rat 43500801 LC50>2.03 mg/L (no 

deaths) III

870.2400 Acute eye irritation rabbit 43553203 Corrosive I

870.2500 Acute dermal irritation rabbit 43553202 Non-irritating IV

Toxicological PoDs Used for Risk Assessment

For risk assessment purposes, all toxicological values are expressed in terms of boron.

Incidental oral and short- and intermediate-term inhalation exposures were evaluated based on 

the 90-day and 2-year dog oral studies (considered together to provide the NOAEL and LOAEL) 

on borax (MRID 40692308 and 40692310). The subchronic study was conducted using borax, 

and the chronic study was conducted with boric acid. The findings of the 90-day, 38-week and 

2-year dietary studies on boric acid were essentially the same as the studies on borax. The 

selected point of departure of 8.8 mg/kg bw/day (the highest dose tested (HDT) in the chronic 

study) was based on hematological findings (decreased Hct/Hgb and increased hemosiderin 

deposition in the spleen, liver and kidneys) and testicular atrophy observed at the LOAEL of 32 

mg/kg bw/day in the 90-day study. Testicular atrophy was also observed at 40 mg/kg bw/day in 

a dog 38-week study (only one dose tested). The observed effects are relevant to all exposed 
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populations, which may include young children and females age 13 to 49. The dose is protective 

of toxicity observed in several oral rat studies (clinical findings, testicular atrophy) including the 

subchronic oral rat studies on borax (NOAEL 41 mg/kg bw/day, HDT) and boric acid 

(NOAEL/LOAEL 38/125 mg/kg bw/day), as well as the rat chronic toxicity study on boric acid 

and borax (NOAEL/LOAEL 17/58 mg/kg/day), and rat reproductive toxicity studies. The 

selected dose and endpoint are also protective of mild renal histopathology seen in pregnant mice 

(≥43 mg/kg/day) in the developmental toxicity study. The selected dose is protective of 

developmental toxicity observed in the rat at 13.3 mg/kg bw/day and the rabbit at 43 mg/kg 

bw/day with developmental NOAELs of 9.6 and 22 mg/kg bw/day, respectively. The inhalation 

absorption of boric acid/borate salts is assumed to be 100% (i.e., is considered to be equivalent to 

toxicity via the oral route).

For inhalation exposure, the endpoint and point of departure selection (NOAEL of 8.8 

mg/kg/day, dog chronic study) considered a published report on inhalation toxicity in the rat. 

The requirement for a rat subchronic inhalation toxicity study was waived (K. Rury, TXR No. 

0056768, 2/5/2014), based on data indicating physical limitations in generating test atmosphere 

concentrations high enough to elicit toxicity (Wilding et al., 1959). The published inhalation 

study did not identify adverse systemic or portal of entry effects in the rat at test concentrations 

up to 0.47 mg/L boron oxide, which is equivalent to an estimated oral exposure of about 29 

mg/kg bw/day boron in the rat.

2

In the absence of observed toxicity in the rat inhalation study, 

the highest exposure concentration tested (0.47 mg/L) was assumed to be a NOAEL for portal of 

entry (POE) and systemic toxicity. Human equivalent doses (HEDs) were calculated for 

comparison to the oral dose of 8.8 mg/kg/day selected for risk assessment and the POE effect 

levels. POE HEDs of 3.65 and 1.49 mg/kg bw/day (males) were obtained for occupational and 

non-occupational HEDs, respectively (systemic HEDs were higher). Although lower than the 

oral dose, they are comparable for risk assessment purposes to the selected oral PODs based on

the differences in UFs used for inhalation HEDs (30) and oral doses (100). The selected oral 

dose (NOAEL) is therefore considered protective of potential POE effects from inhalation 

exposure.

Additionally, a POD was selected to assess the potential ingestion of recently applied granular 

formulation products (e.g., in turf) by young children (e.g., 1 < 2 years old). For this scenario, a 

dose of 350 mg/kg was selected, based on clinical signs (depression, labored/rapid breathing, 

diarrhea, red crusts on eyes) and mortality observed in oral LD50 studies for boric acid and borax 

at doses ≥439 mg/kg. The LD50 studies were selected since no single-dose effects relevant to this 

subpopulation were observed in other guideline toxicology studies. Clinical signs of toxicity in 

repeated-dosing studies were not observed by the first or second day of treatment. In several oral 

LD50 studies (MRIDs 00056544, 00064207, 40692303), no effects were observed at doses of 350 

mg/kg bw boron equivalents. This endpoint is further supported by the lack of toxicity observed 

in the rat acute neurotoxicity screening study at the highest dose level of 350 mg/kg boron 

equivalents.

 

2 Calculation: chamber concentration x species specific adjustment factor (respiratory volume and body weight) x 

exposure duration x 0.311 (factor to convert to boron equivalents for boron oxide)

For the rat, 0.47 mg/L x 47 (Fisher rat) x 6 hr exposure duration x [5 days/7 days per week exposure] x 0.311
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A dermal endpoint was not selected, based on in vivo dermal absorption data in humans and 

published studies in animals indicating that absorption across intact skin is negligible (<1%). 

Estimation of a dermal NOAEL using the NOAELs from the most sensitive oral studies 

(NOAEL = 8.8 mg/kg/day, dog and 9.6 mg/kg/day, developmental rat) using a DAF of 1% 

would yield a dose approaching the limit dose of 1000 mg/kg bw/day.

HED considers the potential for concurrent exposure via different routes that produce the same 

toxicological effects. In the event that the same toxicological effect is produced upon exposure 

through different routes, HED combines those exposures. Incidental oral and inhalation 

exposures are being regulated based on the same effects (hematological changes, testicular 

toxicity) observed following oral exposure in the dog.

For all exposure scenarios, uncertainty factors (UFs) of 10x for interspecies (UFA), 10x for 

intraspecies (UFH) variation, and 1x for the Food Quality Protection Act (FQPA) safety factor 

(total UF of 100x) were used, thus characterization of risk estimates, in the form of Margins of 

Exposure (MOEs) are based on a level of 100. The interspecies factor is considered to be 

conservative because boric acid/borate salts are expected to show similar absorption and tissue 

distribution among different species, and boric acid is not metabolized. The 10x UFA accounts 

for variability in renal clearance between species that may affect elimination of boric acid/borate 

salts, as well as providing additional protection for the close spacing of the rat developmental 

toxicity NOAEL and LOAEL (9.6 and 13.3 mg/kg bw/day, respectively). The FQPA factor is 1x

based on an adequate toxicology database, well-characterized and clear NOAELs and LOAELs, 

dose selection being protective of potential developmental toxicity, and use of conservative 

inputs and models for exposure assessment.

There was no evidence of carcinogenicity in cancer studies with mice and rats, although the 

studies were not conducted according to current guideline standards for carcinogenicity studies. 

Boric acid/borate salts are classified as “not likely to be carcinogenic to humans” under the 

Agency revised (2005) Cancer Guidelines. Genotoxicity studies did not indicate mutagenic or 

clastogenic potential. Epidemiological data do not indicate any boron exposure-related cancers 

in humans. Boron is a ubiquitous, naturally occurring element in food and drinking water to 

which humans are continuously exposed throughout their lifetime, further reducing concern for 

pesticide-related contribution to carcinogenicity.

Body Weight

Though the toxicological point of departure (PODs) for adult inhalation assessments were based 

partly on testicular effects, overall toxicity was seen in both genders, thus, the body weight 

appropriate for risk assessment is 80 kg (representing both males and females). A body weight 

of 11 kg was used for assessment of incidental oral exposure to children. 

A summary of the toxicological doses and endpoints for occupational and residential human 

health risk assessment is provide in Table 3.2.
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3.2 Summary of Toxicological Doses and Endpoints for Boric Acid/Borate Salts for Use in Occupational 

and Residential Human Health Risk Assessments. All doses expressed as boron equivalents.

Exposure/

Scenario

Point of 

Departure

Uncertainty/

FQPA Safety 

Factors

Level of 

Concern for 

Risk 

Assessment

Study and Toxicological Effects

Incidental 

Oral ShortTerm (1-30 

days) and 

IntermediateTerm (1-6 

months)

NOAEL= 8.8

mg/kg bw/day

(2-year feeding 

study – dog, 

HDT)

UFA= 10x

UFH=10x

FQPA SF=1x

Residential 

LOC for MOE 

= 100

Subchronic (90-day) and chronic (2-year) 

feeding study (borax) -- dog 

LOAEL (90-day study) = 32 mg/kg 

bw/day, based on hematological effects 

and testicular atrophy

Dermal (all 

durations)

A dermal risk assessment was not performed. Dermal absorption data in humans indicates 

negligible absorption (less than 1%) and is consistent with published reports in laboratory 

animals showing low or no absorption. Estimation of a dermal NOAEL, using available oral 

NOAELs and a DAF of 1%, would give doses approaching the limit dose (1000 mg/kg bw/day). 

Dermal risks are therefore not of concern. 

Inhalation 

Short- Term 

(1-30 days)

IntermediateTerm (1-6 

months)

NOAEL= 8.8

mg/kg bw/day

(2-year feeding 

study – dog, 

HDT)

100% 

inhalation 

absorption 

assumed.

UFA= 10x

UFH=10x

FQPA SF=1x

Residential and 

Occupational 

LOC for MOE 

= 100

Subchronic (90-day) and chronic (2-year) 

feeding study (borax) -- dog 

LOAEL (90-day study) = 32 mg/kg 

bw/day, based on hematological effects 

and testicular atrophy

Acute 

Incidental 

Oral 

(ingestion of 

granule 

formulations)

NOAEL = 350 

mg/kg

UFA= 10x

UFH=10x

 FQPA SF=1x

Residential 

LOC for MOE 

= 100

Acute LD50 (boric acid and borax, 3 

studies) – rat

LOAELs ≥439 mg/kg, based on clinical 

signs of toxicity and mortality

Cancer (oral, 

dermal, 

inhalation)

Classification: “Not likely to be Carcinogenic to Humans” based on the lack of an increase in 

treatment-related increased tumors in rat and mouse carcinogenicity studies.

Point of Departure = 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. UFA = extrapolation from animal to human (interspecies). UFH = potential variation in 

sensitivity among members of the human population (intraspecies). FQPA SF = FQPA Safety Factor. HDT –

highest dose tested.

4.0 Exposure and Use Profile 

There are many pesticide products containing boric acid or one of its sodium salts as the active 

ingredient. These products include insecticides, acaricides, herbicides, algaecides, fungicides 

and wood preservatives. A summary of the use profile is provided below.

 Registered formulations include dusts, granules/pellets/baits, wettable or water-soluble 

powders/dusts, liquid concentrates, and gels/pastes.

 Use sites and targets include:
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o Agricultural food/feed crops;

o Residential areas (homes, schools, nursing homes, hospitals, etc.):

 Indoor (pet quarters, floors/carpets, attics; cracks/crevices, around 

appliances, bedding/mattresses);

 Outdoor (lawns, parks, golf courses, building perimeters, patios, 

driveways, trash areas, wood piles, gardens);

o Pre-construction wood material;

o Wooden structures (utility poles, railroad ties, etc.);

o Structural Building/House Components (wall/cabinet voids, soffits, attic space, 

crawl spaces)

o Swimming pools;

o Food handling/storage/processing sites;

o Poultry houses;

o Industrial areas;

o Sewers/sewage systems;

o Tree stumps;

o Vehicles (ships, buses, etc.);

o Ant mounds.

 Depending on the use pattern, the percentage of active ingredient ranges from less than 

1% (e.g., liquid concentrate for use on crops) to 100% (e.g., indoor insecticide dusts).

 Application types can be broadcast as well as spot or crack-and-crevice type treatments.

 Applications are made via hand dispersal, with handheld equipment (e.g., rotary 

spreaders, handwand sprayers), and with vehicles (e.g., tractor-drawn spreaders, airblast 

sprayers). Chemigation and aerial applications are prohibited.

 Application rates vary depending on the use site/target and formulation. For example, in 

terms of boron equivalents, spray application to crops has a relatively low rate of 0.0018 

lb boron/acre, while applications of dusts to poultry houses has a relatively high rate of 

448 lb boron/acre.

 The minimum retreatment interval for crop uses is 7 days; non-crop uses are applied on 

an as-needed basis.

 Work attire and/or personal protective equipment (PPE) is not specified on many labels 

while on others, such as the crop use product (EPA Reg. No. 72662-3) the label requires 

protective eyewear/goggles, long-sleeve shirt, pants, waterproof gloves, shoes and socks. 

Some labels require use of respiratory protection.

 For many products, such as those not subject to the EPA’s Worker Protection Standard, a 

restricted entry interval (REI) does not apply. Where applicable, the REI varies from 4 

hours on some labels to 48 hours on other labels.

As there are numerous products with boric acid/sodium salts, Table 4.1 below outlines 

representative registered products on which the exposure and risk assessment is based. 

Application rates are presented in terms of boron equivalents for purposes of comparison with 

toxicological studies – conversions from boric acid or a specific sodium salt are performed using 

the molecular weight composition of boron in the active ingredient.
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Table 4.1. Summary of Registered Use Directions for Boric Acid and its Sodium Salts

Application 

Type/Equip/etc.

Formulation 

[Representative EPA 

Reg. No.]

Maximum Application Rate1 PPE/Work Attire, REI, 

Retreatment

Grass/Turf (Homes, Parks, Golf courses), Ant mounds, Building Perimeters

Broadcast application 

via:

 Tractor-drawn 

spreader

 Hand dispersal

 Belly grinder

 Cup/Spoon

 Push-type rotary 

spreader

Granule (insecticide)

EPA Reg. No. 19713-

522 (Drexel Borxel)

5% boric acid

Product rate 4 lb product/1000 ft2

 Retreatment not 

specified

 PPE: eyewear/goggles, 

long sleeve shirt, long 

pants, waterproof gloves, 

shoes/socks

 REI not specified

Active 

ingredient rate

0.2 lb boric acid/1000 ft2

9 lb boric acid/acre

Boron 

equivalent rate

1.5 lb boron/acre

0.035 lb boron/1000 ft2

Golf Course Turf and Agricultural Food/Feed Crops

(alfalfa, cane berries, bush berries, coffee, cacao, pome fruit, stone fruit, citrus, herbs, tree nuts, peanuts, 

strawberry, tobacco, Brassica leafy vegetables, bulb vegetables, corn, cucurbit, fruiting vegetables, leafy 

vegetables, except Brassica, legumes, root and tuber vegetables, soybean, cotton, herbs, avocado, kava, 

banana, guava, papaya, pineapple, watermelon and grasses) and Golf Course Turf

Broadcast application 

via:

 Groundboom 

sprayer

 Airblast sprayer

 Chemigation 

and aerial 

application is 

prohibited

Liquid concentrate 

(insecticide)

EPA Reg. No. 72662-3

(Prev-Am Ultra)

0.99% sodium 

tetraborohydrate 

decahydrate (STD)

Product rate

100 fl oz/100 gal soln

25 gal soln/acre

 Minimum retreatment is 

7 days.

 PPE: eyewear/goggles, 

long sleeve shirt, long 

pants, waterproof gloves, 

shoes/socks

 REI: 12 hours

Active 

ingredient rate

0.00065 lb STD/gal soln

(product rate * 8.34 

lb/gal soln * 0.99% ai)

0.016 lb STD/acre

(0.00065 lb STD/gal soln 

* 25 gal soln/acre)

Boron 

equivalent rate 0.0018 lb boron/acre

Home gardens, lawns, greenhouses, ornamentals, shrubs

Broadcast application 

via hand sprayers 

(e.g., hose-end 

sprayers, handwand 

sprayers)

Liquid concentrate 

(insecticide)

EPA Reg. No. 72662-5

(Prev-Gard)

0.99% sodium 

tetraborohydrate 

decahydrate (STD)

Product rate

1 fl oz. product/gal soln.

1 gal soln/1000 ft2

 Spray every 7-10 days or 

as frequently as every 4 

days

 PPE: eyewear/goggles, 

long sleeve shirt, long 

pants, waterproof gloves, 

shoes/socks

 REI: 12 hours

Active 

ingredient rate

0.00065 lb STD/gal 

soln/1000 ft2

(product rate * 8.34 

lb/gal soln * 0.99% ai)

0.03 lb STD/acre

Boron 

equivalent rate

0.000073 lb boron/gal 

soln/1000 ft2

0.003 lb boron/acre

Tree Stumps

Application via 

shaker can or hand 

sprayers

Dust/powder 

(fungicide)

EPA Reg. No. 2935-

501

(Sporax)

Product rate

1 lb/50 ft2stump surface 

(equiv. 250 six inch 

stumps)

1 lb/gal soln/50 ft2stump 

surface (assume 1 gallon 

water dilution)

 Spray every 7-10 days or 

as frequently as every 4 

days

 PPE: eyewear/goggles, 

long sleeve shirt, long 

pants (or coveralls), 
Page 14 of 60

Table 4.1. Summary of Registered Use Directions for Boric Acid and its Sodium Salts

Application 

Type/Equip/etc.

Formulation 

[Representative EPA 

Reg. No.]

Maximum Application Rate1 PPE/Work Attire, REI, 

Retreatment

100% sodium 

tetraborohydrate 

decahydrate (STD)

Active 

ingredient rate

1 lb STD/gal soln/50 ft2

(product rate * 100% ai)

waterproof gloves, 

shoes/socks

 REI: 48 hours

Boron 

equivalent rate

0.11 lb boron/gal soln/50 

ft2

0.0023 lb boron/gal 

soln/ft2

Indoor Crack-and-crevice (Residential, Commercial, Recreational) and Sewers

Application via 

shaker can, bulb 

dusters, power 

dusters

Dust (insecticide)

EPA Reg. No. 56-73

(Eaton’s Answer)

99% boric acid

Product rate

20 oz container

12 oz/190 ft2

 No retreatment, PPE, or 

REI specified

Active 

ingredient rate

19.8 oz boric acid/20 oz 

container

11.9 oz boric acid/190 ft2

Boron 

equivalent rate

0.22 lb boron/20 oz 

container

0.00068 lb boron/ft2

30 lb boron/acre

Application via hand 

dispersal

Granule (insecticide)

EPA Reg. No. 64405-2

(Redzone Bait)

5% boric acid

Product rate 2 lb/1000 ft2

 PPE: eyewear/goggles, 

long sleeve shirt, long 

pants, waterproof gloves, 

shoes/socks

 REI: 4 hours

 No retreatment specified

Active 

ingredient rate 0.1 lb boric acid/1000 ft2

Boron 

equivalent rate

0.017 lb boron/1000 ft2

0.76 lb boron/acre

Structural Building/House Components (wall/cabinet voids, soffits, attic space, crawl spaces)

Application via bulb 

and power dusters

Dust/Wettable Powder

(insecticide/fungicide)

EPA Reg. No. 64405-8

(Nibor Borate)

98% disodium 

octaborate tetrahydrate 

(DOT)

Product rate

0.5 oz/ft2

1.5 lb/gal water

 PPE: eyewear/goggles, 

long sleeve shirt, long 

pants, waterproof gloves, 

shoes/socks, respirator in 

confined spaces

 REI: 48 hours

 No retreatment specified

Active 

ingredient rate

0.49 oz DOT/ft2

1.47 lb DOT/gal soln

Boron 

equivalent rate

0.21 lb boron/lb product

0.1 oz boron/ft2

0.0065 lb boron/ft2

0.31 lb boron/gal soln

Application via hand 

sprayers (backpack, 

handgun, airless 

sprayers, 

brush/rollers)

Liquid concentrate 

(insecticide/fungicide)

EPA Reg. No. 83465-1

(GB-40)

Product rate

1 gallon product per 1 

gallon water = 1 gal 

prod/2 gal soln

(1 gallon product = 11.5 

lbs)

 PPE: eyewear/goggles, 

long sleeve shirt, long 

pants, chemical resistant 

gloves, shoes/socks, 

respirator in confined 
Page 15 of 60

Table 4.1. Summary of Registered Use Directions for Boric Acid and its Sodium Salts

Application 

Type/Equip/etc.

Formulation 

[Representative EPA 

Reg. No.]

Maximum Application Rate1 PPE/Work Attire, REI, 

Retreatment

40% disodium 

octaborate tetrahydrate 

(DOT)

Active 

ingredient rate

2.3 lb DOT/gal soln

(product rate * 40% ai)

spaces

 REI: 48 hours

 No retreatment specified

Boron 

equivalent rate 0.32 lb boron/gal soln

Poultry House, Soil/Manure, Garbage/Municipal Dumps

Application via bulb 

and power dusters 

and via hand sprayers

Dust/Wettable Powder 

(insecticide)

EPA Reg. No. 1624-11

(Polybor 3)

98% disodium 

octaborate tetrahydrate 

(DOT)

Product rate

5 lb/100 ft2

2 lb/gal water

3 gal soln/100 ft2

 PPE: eyewear/goggles, 

long sleeve shirt, long 

pants, chemical resistant 

gloves, shoes/socks, 

respirator under certain 

conditions

 REI not specified

 No retreatment specified

Active 

ingredient rate

4.9 lb DOT/100 ft2

0.65 lb DOT/gal soln

Boron 

equivalent rate

1 lb boron/100 ft2

0.14 lb boron/gal soln

448 lb boron/acre

Indoor Residential Carpets, Rugs, Upholstery

Application via hand 

sprayers

RTU Solution 

(insecticide)

EPA Reg. No. 64405-6

(RTU Flea Spray)

8.5% disodium 

octaborate tetrahydrate 

(DOT)

Product rate 1 gal/750 ft2

 No retreatment, PPE, or 

REI specified

Active 

ingredient rate

0.71 lb DOT/gal soln

(1 gal prod * 8.34 lb/gal 

* 8.5% ai)

0.00095 lb DOT/ft2

Boron 

equivalent rate

0.15 lb boron/gal soln

0.0002 lb boron/ft2

Application via hand 

sprayers

Dust/Wettable powder 

(insecticide)

EPA Reg. No. 67419-1

(Ecology Works)

98% disodium 

octaborate tetrahydrate 

(DOT)

Product rate

1 cup/0.5 gal water

1 cup/100 ft2

 Reapply every 8 weeks

 No PPE or REI specified

Active 

ingredient rate

0.86 lb DOT/gal soln

(1 cup * 200 grams/cup * 

1 lb/454 grams * 98% ai)

0.0043 lb DOT/ft2

Boron 

equivalent rate

0.18 lb boron/gal soln

0.0009 lb boron/ft2

Bed Bug Treatments (Mattresses, Bed Frames, Floorboards, Baseboards, Carpets, Walls)

Application via hand 

sprayers

RTU Solution 

(insecticide) Product rate 5 ounces/ft2  No retreatment, PPE, or 

REI specified
Page 16 of 60

Table 4.1. Summary of Registered Use Directions for Boric Acid and its Sodium Salts

Application 

Type/Equip/etc.

Formulation 

[Representative EPA 

Reg. No.]

Maximum Application Rate1 PPE/Work Attire, REI, 

Retreatment

EPA Reg. No. 64405-6

(RTU Flea Spray)

8.5% disodium 

octaborate tetrahydrate 

(DOT)

Active 

ingredient rate

0.71 lb DOT/gal soln

(1 gal prod * 8.34 lb/gal 

* 8.5% ai)

0.028 lb DOT/ft2

Boron 

equivalent rate

0.15 lb boron/gal soln

0.0058 lb boron/ft2

Industrial Areas, Lots, Fence Lines, Runways, Underneath Asphalt, Wood Decks, Bleachers

Broadcast application 

via:

 Tractor-drawn 

spreader

 Hand dispersal

 Belly grinder

 Cup/Spoon

 Push-type rotary 

spreader

 Backpack

Granule (herbicide)

EPA Reg. No. 33560-

46 (Barespot)

49% sodium metaborate

Product rate 3 lb product/100 ft2

 PPE: eyewear/goggles, 

coveralls over long 

sleeve shirt and long 

pants, chemical resistant 

gloves, shoes/socks

 REI not specified

 No retreatment specified

Active 

ingredient rate

1.5 lb sodium 

metaborate/100 ft2

653 lb sodium 

metaborate/acre

Boron 

equivalent rate 105 lb boron/acre

1 Conversions to boron are performed based on the compound’s molecular weight percentage:

Boric acid: 17.48% boron (multiply ai rate by 0.1748)

Sodium tetraborate decahydrate: 11.34% boron (multiply ai rate by 0.1134)

Sodium tetraborate pentahydrate: 14.85% boron (multiply ai rate by 0.1485)

Sodium tetraborate anhydrous: 21.5% boron (multiply ai rate by 0.215)

Disodium octaborate tetrahydrate: 20.96% boron (multiply ai rate by 0.2096)

Disodium octaborate anhydrous: 25.83% boron (multiply ai rate by 0.2583)

Sodium metaborate: 16.41% boron (multiply ai rate by 0.1641)

Considering the use pattern, dermal and inhalation exposures are anticipated for both 

occupational and residential handlers (mixer/loaders, applicators, etc.). In addition, postapplication exposures are also possible, including dermal exposures to re-entry field workers, 

and dermal and incidental oral exposures to children playing on treated grass as well as via spray 

drift resulting from crop applications.

5.0 Residential Exposure and Risk Estimates

There are numerous conventional residential uses of boric acid or its sodium salts as active 

ingredients, from insecticide and fungicide dusts and sprays to granular herbicides. Additionally, 

there are antimicrobial uses in swimming pools and as wood preservatives, however, those are 

addressed in a separate assessment.

Given these uses, both residential handler and post-application exposures are anticipated. 

Addressed below are inhalation exposures for consumers mixing/loading and applying boric acid 

products as well as post-application inhalation and incidental oral exposures resulting from areas 

previously treated with boric acid products. As described previously, dermal toxicity was not 

identified, thus dermal risks are not quantitatively addressed.
Page 17 of 60

Note also, as boric acid and its sodium salts are classified as “Not Likely to be Carcinogenic to 

Humans” only non-cancer risks are quantified.

5.1 Residential 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 tasks related to applications and that 

exposures can vary depending on the specifics of each task. Residential handlers are addressed 

somewhat differently by HED as homeowners are assumed to complete all elements of an 

application without use of any protective equipment.

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

following scenarios.

 Indoor area treatments (carpets, floors, crack-and-crevice treatments, attics, wall voids, 

crawl spaces, etc.)

o Loading/applying dust/powder formulations with:

 Hand pressure dusters (e.g., bulb dusters, plunger dusters, hand crank 

dusters)

 Power dusters/blowers

 Shaker cans

o Applying granules/baits via hand dispersal

o Mixing/loading/applying wettable dusts/powder formulations with a manually 

pressurized handwand sprayer

o Mixing/loading/applying liquid concentrate formulations with a manually 

pressurized handwand sprayer

o Applying bait gels/pastes

 Outdoor area treatments (lawns, gardens, shrubs/bushes, and fruit/nut trees)

o Loading/applying granule formulations with push-type rotary spreaders

o Applying granule formulations via hand dispersal or with spoons or cups

o Mixing/loading/applying liquid concentrate formulations with

 Manually pressurized handwand sprayers

 Hose-end sprayers

 Backpack sprayers

 Sprinkler cans

Residential Handler Exposure Data and Assumptions

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

handler risk assessments. Each assumption and factor is detailed below.

Application Rate: 

Various application rates are provided in Table 4.1 and are applied for specific scenarios and 

application methods.
Page 18 of 60

Unit Exposures and Area Treated or Amount Handled:

Unit exposure values and estimates for area treated or amount handled were taken from HED’s 

2012 Residential SOPs3. Where default values are not provided in the SOPs, the assessment 

considers label language regarding the extent of the treatment as well as professional judgment 

considering house size and application capabilities of consumers.

Exposure Duration:

Residential handler exposure is generally expected to be short-term in duration, though given 

many boric acid/sodium salt labels don’t specify treatment frequency and the use of boric acid 

and its sodium salts is likely on an as-needed basis (particularly its residential insecticide use), 

there is potential for intermediate-term handler exposure as well. However, the toxicological 

endpoint selected for the short-term assessment is protective of both short- and intermediate-term 

durations.

Residential Handler Non-Cancer Exposure and Risk Estimate Equations

The algorithms used to estimate exposure and dose for residential handlers can be found in the 

2012 Residential SOPs4and Appendix A.

Combining Exposures/Risk Estimates

Residential handler dermal and inhalation exposures were not combined because dermal toxicity

was not identified in the boric acid toxicity database.

Summary of Residential Handler Non-Cancer Exposure and Risk Estimates

Inhalation exposures and risks were calculated for residential handlers assuming no respiratory 

protection; no estimates of inhalation risk were of concern. 

Table 5.1.1 presents detailed exposure and risk calculations.

 

3 Available: http://www.epa.gov/pesticides/science/residential-exposure-sop.html

4 Available: http://www.epa.gov/pesticides/science/residential-exposure-sop.html
Page 19 of 60

Table 5.1.1. Summary of Residential Handler Risk Estimates for Boric Acid and its Sodium Salts

Use Site 

Category Exposure Scenario App Rate1

Amount 

Handled/Area 

Treated2

Unit Exposure 

(mg/lb ai)3 Dose (mg/kg/day)4

Inhalation MOE5

Inhalation (LOC = 100)

(no respirator)

Inhalation

(no respirator)

Indoor 

treatments

Mixing / loading

/ applying with a 

manually 

pressurized 

handwand

Liquids 0.15 lb ai/gallon 

dilute solution 0.5 gallons dilute 

solution

1.1 0.001 8500

Wettable 

dusts/powders

0.31 lb ai/gallon 

dilute solution 1.1 0.0021 4100

Applying granules/baits via hand 

dispersal 0.000017 lb ai/ft2 1000 ft2 0.38 0.000081 110000

Loading / 

applying 

dusts/powders

Shaker can 0.22 lb ai/20 oz 

container

One 20 oz 

container 18 0.05 180

Power 

duster/blower 0.21 lb ai/lb dust 1 lb dust 18 0.024 370

Bulb Duster 0.21 lb ai/lb dust 0.25 lb dust 1.7 0.0011 7900

Plunger Duster 0.21 lb ai/lb dust 0.5 lb dust 1.7 0.0022 3900

Applying bait gels/pastes No exposure/risks expected from gel/paste formulations.

Outdoor 

treatments

(lawns, 

gardens, 

and trees)

Loading / 

applying 

granules 

Rotary spreader 1.52 lb ai/acre 0.5 acres 0.0026 0.000025 360000

Belly grinder 0.034 lb ai/1000 

ft2 1200 ft2 0.039 0.00002 430000

Spoon 0.034 lb ai/1000 

ft2 1200 ft2 0.013 0.00054 1300000
Page 20 of 60

Table 5.1.1. Summary of Residential Handler Risk Estimates for Boric Acid and its Sodium Salts

Use Site 

Category Exposure Scenario App Rate1

Amount 

Handled/Area 

Treated2

Unit Exposure 

(mg/lb ai)3 Dose (mg/kg/day)4

Inhalation MOE5

Inhalation (LOC = 100)

(no respirator)

Inhalation

(no respirator)

Cup

0.034 lb ai/1000 

ft2 1200 ft2 0.087 0.000046 190000

Applying granules via hand 

dispersal

0.034 lb ai/1000 

ft2 1200 ft2 0.38 0.0002 44000

Mixing / loading

/ applying liquids

Manually 

pressurized 

handwand

0.000073 lb 

ai/gallon dilute 

solution

5 gallons dilute 

solution 0.018 8.2E-08 110000000

Hose-end 

sprayer

0.003 lb ai/acre 0.5 acres 0.022 4.1E-07 21000000

Backpack 

sprayer

0.000073 lb 

ai/gallon dilute 

solution

5 gallons dilute 

solution 0.14 6.4E-07 14000000

Sprinkler can 0.000073 lb 

ai/1000 ft2 1000 ft2 0.022 2.0E-08 440000000

1 Based on registered labels outlined in Table 4.1. All rates expressed in terms of boron.

2 Based on HED’s 2012 Residential SOPs (http://www.epa.gov/pesticides/science/residential-exposure-sop.html).

3 Inhalation Dose = Inhalation Unit Exposure (mg/lb ai) × Application Rate (lb ai/acre or gal) × Area Treated or Amount Handled (A/day or gallons/day) ÷ BW (kg). Expressed 

in terms of boron.

4 Inhalation MOE = Inhalation POD (mg/kg/day) ÷ Inhalation Dose (mg/kg/day).
Page 21 of 60

5.2 Residential Post-application Exposure/Risk Estimates

There is the potential for post-application exposure for individuals exposed as a result of being in 

an environment that has been previously treated with boric acid or a borate sodium salt. As no 

dermal toxicity was identified, the quantitative exposure/risk assessment for residential postapplication exposures is based on the following scenarios:

 Inhalation exposure for adults and children (1 < 2 years old) following indoor treatments 

(carpets, floors, crack-and-crevice, bedding/mattresses)

 Incidental oral children’s (1< 2 years old) exposure from contact with treated:

o Turf/lawns

o Carpets and floors

The lifestages selected for each post-application scenario are based on an analysis provided as an 

Appendix in the 2012 Residential SOPs5. While not the only lifestage potentially exposed for 

these post-application scenarios, the lifestage that is included in the quantitative assessment is 

health protective for the exposures and risk estimates for any other potentially exposed lifestage.

Residential Post-application Exposure Data and Assumptions

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

post-application risk assessment. Each assumption and factor is detailed in the 2012 Residential 

SOPs and Appendix A.

Application Rate:

Various application rates are provided in Table 4.1 and are applied for specific scenarios and 

application methods.

Application rates were utilized in conjunction with molecular weights (in grams/mole) and vapor 

pressures (in mmHg) shown in the table below to estimate air concentrations via volatilization of 

liquid indoor sprays.

Compound Molecular weight (g/mol) Vapor pressure (mmHg)

Boric acid 61.83 < 10-4

Sodium tetraborate decahydrate (STD) 381.43

< 10-6

Sodium tetraborate pentahydrate 291.35

Sodium tetraborate anhydrous 201.22

Disodium octaborate tetrahydrate 412.31

Disodium octaborate anhydrous 340.31

Sodium metaborate 65.82

 

5 Available: http://www.epa.gov/pesticides/science/residential-exposure-sop.html
Page 22 of 60

Exposure Duration:

Post-application exposures are generally considered short-term in nature. However, the toxicity 

study from which the inhalation and incidental oral toxicological endpoints were selected to 

assess post-application exposures is of sufficient duration to assess both short- and intermediateterm exposure durations.

Residue Transferability

In accordance with 40CFR158, turf transferable residue (TTR), dislodgeable foliar residue 

(DFR), and indoor surface residue data are required for all occupational or residential uses that 

could result in post-application exposures. In the absence of chemical-specific residue data, 

EPA uses default values. Since no systemic dermal toxicity was identified and the estimated 

residential turf incidental oral post-application exposure using default TTR values for boric 

acid/sodium salts is minimal in comparison to the level of concern (i.e., the calculated MOE is 

greater than 10 times higher than the level of concern, MOEs ≥ 10,000 compared to the LOC of 

100), TTR data are not needed. For this scenario, it is unlikely that chemical-specific residue

data would be needed to further refine exposure assessments or would add appreciably to 

our general understanding of the availability of turf transferable residues.

For indoor surface residues, during and after the boric acid and its sodium salts Tolerance 

Reregistration Eligibility Decision (TRED) process in 1995/1996, registrants submitted studies 

aimed at informing and refining estimates for post-application indoor exposures, in particular 

residue transferability. All residue transferability estimates were derived using the “California 

roller method”6. As described in the 2012 Residential SOPs, exposure contact factors (i.e., 

transfer coefficients) used to estimate indoor post-application dermal and incidental exposures 

are derived from datasets that utilized the same California roller method and a modified version 

of the California roller method. Thus the submitted studies are consistent with standard 

procedures for estimating indoor post-application exposures, and thus satisfy the 40CFR data 

requirements. 

Across all the studies, which included varying types and conditions of carpets, transferability (as 

a percentage of the application rate) of boric acid/sodium salts ranged from 0.03% to 0.95%. To 

represent typical conditions for short-/intermediate-term post-application risk assessments, 

transferability of 0.1% will be used for dust treatments to carpets (selected from MRID 

47579901) and 0.4% for dust treatments to hard floors and liquid treatments to carpets or hard 

surfaces (selected from MRID 47579902, the only result available for these conditions). The

submitted studies are listed and briefly summarized below.

 

6 Ross, J.H., Fong, H.R., Thongsinthusak, T., Margetich, S. and Krieger, R. 1991. Measuring Potential Dermal 

Transfer of Surface Pesticide Residue Generated from Indoor Fogger Use: Using the CDFA Roller Method. 

Interim Report II. Chemosphere, Vol. 22. Nos.9-10:975-984
Page 23 of 60

Title EPA 

MRID Author

Applicability for 

Pesticide Exposure 

Assessment

Contact Transfer of Eco-Fresh Borate 

Treated Surfaces to Evaluate Human 

Exposure Potential

47579902 Robert Krieger (Univ. of California, 

Riverside)

Residue transferability 

from dust-treated carpets 

and solution-treated hard 

floors

Contact Transfer of Flea-Be-Gone 

Insecticide from Carpets to Evaluate 

Human Exposure Potential

47579901

Robert Krieger (Univ. of California, 

Riverside)

Residue transferability 

from dust-treated carpets

Dosimetry Study for Rx for Fleas Plus: 

A Toxicology Review of Boric Acid 

and its Salt, Exposure Assessment, and 

Risk Characterization

46971101 Robert Yarmuth, Environmental 

Toxicology International

Residue transferability 

from dust-treated carpets

Human Disodium Octaborate 

Tetrahydrate Exposure Following 

Carpet Flea Treatments Is Not 

Associated with Significant Dermal 

Absorption

46852202

Robert Krieger and Travis Dinoff

(Univ. of California, Riverside) and 

James Peterson (Pacific Toxicology 

Lab). J Expo Anal Env Epi. Vol 6, No. 

3, 1996.

Residue transferability and 

characterizing dermal 

exposure (biomonitoring)

EPA MRID 47579902 – Contact Transfer of Eco-Fresh Borate Treated Surfaces to Evaluate 

Human Exposure Potential

This study was conducted in 1996 by Robert Krieger of the University of California, Riverside 

Dept. of Entomology and submitted to the EPA in 2007 by U.S. Borax Inc. following 

information requests in the EPA TRED for boric acid/sodium salts. The study used the 

“California roller” technique to measure boric acid transferability from treated carpets and 

linoleum floors. No human subjects were involved in the conduct of the study.

The test material (EPA Reg. No. 66480-1, Eco-Fresh, 64% boric acid – a product since 

canceled), a dust, was applied to carpets as a dust at a rate of 3 lb of product per 100 ft2

(equivalent to 9.3 mg boric acid/cm2) and to linoleum floors as a solution at a rate of 197 grams 

product in a gallon of water to 100 ft2of floor (equivalent to 1.3 mg boric acid/cm2).

Transferable surface residue was measured using the “California roller” technique, a method that 

employs a short-handled 25 pound roller, rolled 20 times over a 3,932 cm2cotton percale sheet 

covered by polyethylene, according to the protocol from Ross, 19917. Samples were taken 

before and after treatment; before-treatment samples showed negligible background boron levels. 

Fortification of the cotton percale sampler was done at 3 levels, 0.505 mg, 1.01 mg, and 2.02 mg, 

with results averaging 129%, 114%, and 95% at each of those levels, respectively. 

Transferability results, expressed in terms of a percentage of the application rate are shown in the 

table below. Though conducted without prior EPA consideration of the study protocol, the 

results are reasonable to consider for the purposes of boric acid/sodium salts risk assessment.

 

7 Ross, J.H., Fong, H.R., Thongsinthusak, T., Margetich, S. and Krieger, R. 1991. Measuring Potential Dermal 

Transfer of Surface Pesticide Residue Generated from Indoor Fogger Use: Using the CDFA Roller Method. 

Interim Report II. Chemosphere, Vol. 22. Nos.9-10:975-984.
Page 24 of 60

Transferability Results from MRID 47579902

Application/Surface

Application Rate

(mg boric acid/cm2)

Average Transferable 

Residue1,2,3

(mg boric acid/cm2)

Transfer Efficiency

(% of app. rate)4

Dust to carpet

(“open pile/little wear”)

9.3

0.0008 0.009

0.03

Dust to carpet

(“short pile/more wear”)

0.005 0.05

Solution to linoleum 1.3 0.005 0.4

1 No adjustment for fortification recoveries (results acceptable).

2 Measurements per 3,932 cm2 of sampler.

3 No adjustment for background boron levels which were insignificant.

4 Calculated as measurement divided by rate.

EPA MRID 47579901 – Contact Transfer of Flea-Be-Gone Insecticide from Carpets to Evaluate

Human Exposure Potential

This study was conducted in 1997 by Robert Krieger of the University of California, Riverside 

Dept. of Entomology and submitted to the EPA in 2007 by U.S. Borax Inc. following 

information requests in the EPA TRED for boric acid/sodium salts. The study used the 

“California roller” technique to measure boric acid transferability from treated carpets. No 

human subjects were involved in the conduct of the study.

The test material (EPA Reg. No. 69115-1, Flea-Be-Gone, 65% boric acid – a product since 

canceled), a dust, was applied to carpets as a dust at a rate of 1 lb of product per 500 ft2

(equivalent to 0.63 mg boric acid/cm2).

Transferable surface residue was measured using the “California roller” technique, a method that 

employs a short-handled 25 pound roller, rolled 20 times over a 3,932 cm2cotton percale sheet 

covered by polyethylene, according to the protocol from Ross, 1991. Samples were taken before 

and after treatment; before-treatment samples showed background boron levels ranging from 

0.027 to 0.111 ug boron/cm2. Fortification of the cotton percale sampler was done at 3 levels, 

0.5 mg, 1 mg, and 2 mg, with results averaging 75%, 71%, and 69% at each of those levels, 

respectively. 

Transferability results, expressed in terms of a percentage of the application rate are shown in the 

table below. Though conducted without prior EPA consideration of the study protocol, the 

results are reasonable to consider for the purposes of boric acid/sodium salts risk assessment.

Transferability Results from MRID 47579901

Carpet 

Section

Average Transferable Residue

(ug boric acid/cm2)

1,2 Study Application Rate 

(ug boric acid/cm2)

4

Transfer 

Efficiency 

(%)5

Pre-treatment Post-treatment Corrected3

A 0.0337 0.516 0.482

630

0.0766

E 0.0337 0.661 0.627 0.0996

F 0.027 0.476 0.449 0.0713
Page 25 of 60

G 0.111 0.361 0.250 0.0397

Overall 

average

0.05135 0.5035 0.45215 0.0718

1 Adjusted for 71.8% recovery (overall average)

2 Reflect boric acid measurements normalized to 3932 cm2

3 Corrected = post-treatment minus pre-treatment

4 Rate calculated from a 65% boric acid product applied at a rate of 1 pound per 500 ft2

.

5 Calculated as measurement divided by rate.

EPA MRID 46971101 Dosimetry Study for Rx for Fleas Plus: A Toxicology Review of Boric 

Acid and its Salt, Exposure Assessment, and Risk Characterization

This study was conducted in 1994 by Environmental Toxicology International and submitted to 

the EPA in 2005 by the sponsors Rx for Fleas and InCide Technologies following information 

requests in the EPA TRED for boric acid/sodium salts. In addition to an assessment of boric 

acid/sodium salts toxicology and risk, the study characterized the potential for exposure via 

measurement of residue transfer following application of a boric acid dust product to carpets. No 

human subjects were involved in the conduct of the study.

The test material (EPA Reg. No. 59111-1, Rx For Fleas Plus, 64% boric acid), a dust, was 

applied to carpets as a dust at rates of 9.1 grams of product per ft2(equivalent to 0.013 lb boric 

acid/ft2or 1066 ug boron/cm2) and 3.8 grams of product per ft2(equivalent to 0.0054 lb boric 

acid/ft2or 445 ug boron/cm2).

Transferable surface residue was measured using the “California roller” technique, a method that 

employs a short-handled 25 pound roller, rolled 20 times over a 3,932 cm2cotton percale sheet 

covered by polyethylene, according to the protocol from Ross, 1991. Samples were taken before 

and after treatment; before-treatment samples showed negligible background boron levels. 

Fortification of the cotton percale sampler results averaged approximately 90%. 

Transferability results, expressed in terms of a percentage of the application rate are shown in the 

table below. Though conducted without prior EPA consideration of the study protocol, the 

results are reasonable to consider for the purposes of boric acid/sodium salts risk assessment.

Transferability Results from MRID 47579901

Application Rate1

Carpet/Condition

Residue 

Measurement

(ug boron/cm2)

2

Mean Transfer 

Efficiency (%)3

g prod/ft2 ug boron/cm2

3.8 445

Carpet (standard condition) 0.51 0.11

Carpet (extreme condition) 4.24 0.95

9.1 1066

Carpet (standard condition) 0.95 0.09

Carpet (extreme condition) 3.43 0.32

1 Product is 64% boric acid. Boric acid is 17.48% boron.

2 Reflect boron measurements normalized to 17 in x 17 in sampler (1864 cm2

)

3 Calculated as measurement divided by rate.
Page 26 of 60

EPA MRID 46852202 Human Disodium Octaborate Tetrahydrate Exposure Following Carpet 

Flea Treatments Is Not Associated with Significant Dermal Absorption

This is a published article in the Journal of Exposure Analysis and Environmental Epidemiology

– Krieger, et al. 1996. The study obtained biomonitoring (urine) samples from volunteers 

performing Jazzercise routines on carpets treated with a dust product containing disodium 

octaborate tetrahydrate (DOT). Residue transferability was also measured using the same 

California roller method previously described for the other studies.

Unlike the other available studies described above, the raw data was not presented for discrete 

analysis, thus a determination of the transferability was not pursued.

Residential Post-application Non-Cancer Exposure and Risk Equations

The algorithms used to estimate residential post-application exposure and dose can be found in 

the 2012 Residential SOPs8and Appendix A.

Combining Exposure and Risk Estimates

Based on the available toxicological information for boric acid/borate salts, dermal exposures are 

not anticipated to result in adverse systemic effects due to minimal absorption, and therefore not 

quantitatively assessed. Since incidental oral and inhalation exposures are based on the same 

toxicological effects they are combined.

Summary of Residential Post-application Non-Cancer Exposure and Risk Estimates

Risk estimates of concern were identified for hand-to-mouth exposures for children following 

indoor bedbug treatments (MOE = 8) and indoor carpet spray treatments (MOE = 51). These

routes are also combined with inhalation exposure, but as inhalation exposure is much lower in 

comparison to the hand-to-mouth exposure, the risk estimates are unchanged. 

The application rates are relatively high for pesticide applications, particularly the bed bug 

treatment application rate (based on EPA Reg. No. 64405-6) at approximately 6 pounds of boron 

per 1000 square foot of carpet. Crack-and-crevice treatments – assumed to result in substantially 

less surface residue than broadcast treatments – did not result in risk estimates of concern for 

incidental oral exposure scenarios.

Table 5.2.1 below outlines in more detail the exposure scenarios and exposure and risk 

calculations. Combined exposure scenarios are shown as well for children: incidental oral 

scenarios are combined with post-application inhalation exposure resulting from general indoor 

spray treatments.

 

8 http://www.epa.gov/pesticides/science/residential-exposure-sop.html
Page 27 of 60

Table 5.2.1. Residential Post-application Exposure and Risk Estimates for Boric Acid/Sodium Salts

Lifestage

Post-application Exposure Scenario

Application Rate1 Dose 

(mg/kg/day)2

MOEs3

Use Site Route of Exposure Routespecific Combined5

Adult Bed Bug 

treatments

Carpets Liquids Inhalation

0.71 lb DOT/gallon dilute 

solution

(0.0058 lb boron/ft2)

0.00051 17000 --

Child

Bed Bug 

treatments

Carpets Liquids Inhalation

0.71 lb DOT/gallon dilute 

solution

(0.0058 lb boron/ft2)

0.0022 4000 --

Carpets4 Liquids Hand-to-Mouth 0.0058 lb boron/ft2 1.12 8 8

Object-to-Mouth 0.0058 lb boron/ft2 0.037 240 220

General 

Indoor 

treatments

Carpets4

Liquids Hand-to-Mouth 0.0009 lb boron/ft2 0.17 51 51

Dusts Hand-to-Mouth 0.00068 lb boron/ft2 0.033 270 --

Liquids Object-to-Mouth 0.0009 lb boron/ft2 0.023 380 350

Dusts Object-to-Mouth 0.00068 lb boron/ft2 0.004 2000 --

Hard floors4

Liquids Hand-to-Mouth 0.0009 lb boron/ft2 0.043 200 190

Dusts Hand-to-Mouth 0.00068 lb boron/ft2 0.033 270 --

Liquids Object-to-Mouth 0.0009 lb boron/ft2 0.012 760 620

Dusts Object-to-Mouth 0.00068 lb boron/ft2 0.009 1000 --

Crack-andcrevice

Carpets4

Liquids Hand-to-Mouth 0.0009 lb boron/ft2 0.017 510 460

Dusts Hand-to-Mouth 0.00068 lb boron/ft2 0.0033 2700 --

Liquids Object-to-Mouth 0.0009 lb boron/ft2 0.0023 3800 2000

Dusts Object-to-Mouth 0.00068 lb boron/ft2 0.0004 20000 --

Hard floors4

Liquids Hand-to-Mouth 0.0009 lb boron/ft2 0.0043 2000 1400

Dusts Hand-to-Mouth 0.00068 lb boron/ft2 0.0033 2700 --

Liquids Object-to-Mouth 0.0009 lb boron/ft2 0.0012 7600 2600

Dusts Object-to-Mouth 0.00068 lb boron/ft2 0.0009 10000 --

Child

Outdoor

(lawn, garden, tree 

sprays)

Granules

Hand-to-Mouth

1.52 lb ai/acre

0.0023 3800 --

Object-to-Mouth 0.00014 63000 --

Soil Ingestion 5.1E-05 170000 --

Solid Formulation 

Ingestion

8% boron

(49% sodium metaborate) 2.36 160 --

0.9% boron

(5% boric acid) 0.24 1500 --

Liquids

Hand-to-Mouth

0.003 lb ai/acre

0.00005 19000 --

Object-to-Mouth 0.000001 6300000 --

Soil Ingestion 1E-07 8.7E07 --

1 Based on registered labels outlined in Table 4.1. All rates expressed in terms of boron, except where application rate expressed is expressed in 

terms of the compound with the highest rate – disodium octaborate tetrahydrate (DOT) – in order to calculate volatilization of sprays using 

molecular weight and vapor pressure parameters.

2 Dose (mg/kg/day) algorithms provided in 2012 Residential SOPs (http://www.epa.gov/pesticides/science/residential-exposure-sop.html). 

Expressed in terms of boron.

3 MOE = POD (mg/kg/day) ÷ Dose (mg/kg/day).

4 As described in Section 5.2, transferability from carpet and hard floors following dust treatments estimated at 0.1% and 0.4% respectively and 

transferability following liquid treatments on carpets and hard floors estimated at 0.4%.

5 Combined MOE = POD (mg/kg/day) ÷ [Inhalation Dose + Oral Dose (mg/kg/day)]. Combined exposures are only applicable for children 1<2. 

When a combined MOE is shown the inhalation component is via the scenario for liquid applications to carpet or hard floors (dose = 0.0022 

mg/kg/day, MOE=4000).

5.3 Residential Risk Estimates for Use in Aggregate Assessment

Table 5.3.1 reflects the residential risk estimates from the conventional pesticide uses of boric 

acid and its sodium salts that are recommended for use in an aggregate assessment for boric acid 

and its sodium salts. The residential scenarios recommended for the aggregate assessment are 
Page 28 of 60

generally the short-/intermediate-term scenarios with the highest exposure, except for the 

following situations:

 When the solid formulation ingestion scenario yields the highest exposure – the episodic 

nature of this scenario scenario is not applicable for aggregation with chronic dietary 

exposure; and,

 Scenarios with risk estimates of concern would by default not apply to a quantitative 

aggregate assessment until they are refined or mitigated. In those cases an aggregate 

scenario would also present a risk of concern.

Thus, for boric acid/sodium salts, the recommended scenarios for potential aggregation are the 

following:

 The recommended residential exposure for use in an adult aggregate assessment reflects 

inhalation exposure from indoor applications of dust formulations with a shaker can (dose 

= 0.05 mg/kg-day, MOE = 180).

 The recommended residential exposures for use in a children 1<2 years old aggregate 

assessment reflects the combined exposures from post-application inhalation (0.0022 

mg/kg-day) and hand-to-mouth exposures (0.043 mg/kg-day) following general indoor 

liquid applications to hard floors.

 Post-application combined inhalation plus hand-to-mouth exposures following general 

indoor spray treatments to carpets and bed bug treatments to carpets using liquid 

formulations already presents risks of concern so would not be applicable for aggregate 

risk assessment until risks are mitigated.

 Residential risk estimates resulting from antimicrobial pesticide use are addressed 

separately and may also impact the aggregate risk assessment.

Table 5.3.1. Recommendations for the Residential Exposures for the Boric Acid/Sodium Salt Aggregate Assessment.

Lifestage Exposure Scenario

Dose (mg/kg/day)1 MOE2

Inhalation Oral Total Inhalation Oral Total

Adult Indoor/dust/shaker can 0.05 N/A N/A 180 N/A N/A

Child Indoor/liquids/carpets

and hard floors 0.0022 0.043 0.0452 4000 200 190

1 Dose = the highest dose for each applicable lifestage of all residential scenarios assessed. For adults, inhalation is the only applicable 

route. For children total dose = inhalation + incidental oral.

2 MOE = the MOEs associated with the highest residential doses. Total = 1 ÷ (1/Inhalation MOE) + (1/Incidental Oral MOE)

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. Sprays that are released and do not deposit in the application area end up offtarget and can lead to exposures to those it may directly contact. They can also deposit on 

surfaces where contact with residues can eventually lead to indirect exposures (e.g., children 

playing on lawns where residues have deposited next to treated fields). The potential risk 
Page 29 of 60

estimates from these residues can be calculated using drift modeling coupled with methods 

employed for residential risk assessments for turf products.

The approach to be used for quantitatively incorporating spray drift into risk assessment is based 

on a premise of compliant applications which, by definition, should not result in direct exposures 

to individuals because of existing label language and other regulatory requirements intended to 

prevent them.9 Direct exposures would include inhalation of the spray plume or being sprayed 

directly. Rather, the exposures addressed here are thought to occur indirectly through contact 

with impacted areas, such as residential lawns, when compliant applications are conducted. 

Given this premise, exposures for children (1 to < 2 years old) and adults who have contact with 

turf where residues are assumed to have deposited via spray drift thus resulting in an indirect 

exposure are the focus of this analysis analogous to how exposures to turf products are 

considered in risk assessment.

Boric acid and its sodium salts have existing direct uses on turf, thus it was considered whether 

the risk assessment for that use may be health protective of exposures resulting from spray drift. 

If the maximum application rate on crops adjusted by the amount of drift expected is less than or 

equal to existing turf application rates, the existing turf assessment is considered protective of 

spray drift exposure. The existing maximum single application rate of boric acid/sodium salts 

for various agricultural food/feed crops is 0.0018 lb ai/acre. The highest degree of spray drift 

noted for any application method immediately adjacent to a treated field (Tier 1 output from the 

aerial application using fine to medium spray quality) results in a deposition fraction of 0.26 of 

the application rate. 

A quantitative spray drift assessment for boric acid/sodium salts is not required because the 

maximum application rate to a crop/target site multiplied by the adjustment factor for drift of 

0.26 is less than the maximum direct spray residential turf application rate of 0.003 lb ai/acre

(i.e., 0.0018 lb ai/A x 0.26 ≤ 0.003 lb ai/A). The turf post-application MOEs based on the 

revised SOPs for Residential Exposure Assessment were assessed (see above in Section 5.2) and 

no risks of concern were identified.

7.0 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.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html). 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) or further 

analysis are required for boric acid and its sodium salts.

 

9 This approach is consistent with the requirements of the EPA’s Worker Protection Standard which, 

when included on all labels, precludes direct exposure pathways.
Page 30 of 60

Exposure from volatilization of indoor sprays resulting from residential applications were 

considered and are outlined in Section 5.2 above. No risks of concern were identified. 

8.0 Occupational Exposure and Risk Estimates

There are numerous conventional uses of boric acid or its sodium salts as active ingredients, 

from insecticide and fungicide dusts and sprays to granular herbicides. Additionally, there are 

antimicrobial uses in swimming pools and as material and wood preservatives.

Given these uses, both occupational handler and post-application exposures are anticipated. As 

described above, though dermal exposures are possible, due to negligible dermal absorption, 

toxicity from dermal exposure is not expected and dermal risks are not of concern. Therefore, 

addressed below are inhalation exposures for workers mixing/loading and applying boric acid 

products as well as post-application inhalation resulting from areas previously treated with boric 

acid products.

Inhalation exposures for some occupational handler scenarios have risk estimates of concern 

(MOEs < 100), requiring respirators to mitigate risks. For dust applications to structural building 

components (e.g., attics, crawl spaces, soffits, etc.) and agricultural buildings (e.g., poultry 

houses), standard respirators (i.e., filtering face-pieces) do not mitigate inhalation risk estimates 

of concern. No post-application risks are of concern

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. 

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

following scenarios.

 Loading granules to support tractor-drawn spreader applications

 Mixing/loading liquids to support applications via:

o Airblast sprayers

o Groundboom sprayers

 Loading/applying granules with:

o Backpacks

o Belly grinders

o Spoons or cups

o Rotary spreaders

 Mixing/loading/applying liquid solutions with:

o Airless sprayer
Page 31 of 60

o Brush/roller

o Backpack sprayers

o Manually-pressurized handwand sprayers

o Mechanically-pressurized handgun sprayers

 Mixing/loading dusts/powders with water and applying with manually pressurized 

handwands and mechanically pressurized handguns

 Applying bait gels/pastes

 Applying dusts with:

o Shaker cans

o Bulb dusters

o Plunger dusters

o Power dusters/blowers

 Applying granules via:

o Hand dispersal

o Tractor-drawn spreaders

 Applying sprays with:

o Airblast sprayers

o Groundboom sprayers

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: 

The application rate used in this assessment is provided in Section 4.0 (Table 4.1). 

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, the ORETF 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 FIFRA. 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 Table10”, 

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 website11.

Area Treated or Amount Handled: 

The inputs for area treated or amount of solution or product handled were based on ExpoSAC 

Policy 9.1. The following summarizes the inputs used for estimating handler exposures:

 

10 Available: http://www.epa.gov/opp00001/science/handler-exposure-table.pdf

11 Available: http://www.epa.gov/pesticides/science/handler-exposure-data.html
Page 32 of 60

 10,000 square feet (0.23 acres) for:

o Hand dispersal of granules in food handling establishments or residential living 

spaces

o Dust applications with plunger or power/blower dusters to industrial/commercial 

areas, poultry houses, and structural building components

o Dust applications with a bulb duster to food handling establishments, warehouses, 

and residential living spaces

 1 acre for:

o Hand dispersal of granules to grass, industrial/commercial areas, building 

foundations/perimeters, and ant mounds

o Backpack application of granules to industrial/commercial areas

o Belly grinder application of granules to grass, building foundations/perimeters, 

and industrial/commercial areas

o Spoon or cup applications to building foundations/perimeters and 

industrial/commercial areas

 1 (20 oz.) container of dust for shaker can and bulb duster applications to greenhouses, 

nurseries, landscaping, warehouses, poultry houses, building foundations/perimeters, 

interior landscaping, food handling establishments, residential living spaces, and schools

 5 acres for:

o Liquid spray applications with a groundboom sprayer to golf course tees and 

greens

o Mechanically-pressurized handgun applications of liquid sprays to grass (lawns, 

athletic fields, parks, etc.)

o Granule applications via rotary spreader to golf course turf, ant mounds, grass 

(lawns, athletic fields, parks, etc.), and industrial/commercial areas

 20 acres for airblast applications to nurseries

 40 acres for:

o Tractor drawn spreader applications of granules to golf course turf and grass 

(lawns, athletic fields, parks, etc.)

o Airblast applications to orchards/vineyards

o Groundboom application of liquid sprays to golf course fairways, tees, and 

greens, field-grown ornamental crops, and orchards/vineyards

 40 gallons for:

o Backpack application to orchards/vineyards, greenhouses, nurseries, landscaping 

(grass, flowers, trees), and structural building components

o Manually-pressurized handwand greenhouses, nurseries, landscaping (grass, 

flowers, trees), residential living spaces, and structural building components

o Airless sprayer and brush/roller application of solutions to structural building 

components

 60 acres for:

o Granule applications via tractor drawn spreader to industrial/commercial areas

o Groundboom application to greenhouses and nurseries

 80 acres for groundboom application to typical-acreage field crops

 200 acres for groundboom application to high-acreage field crops

 1000 gallons for mechanically-pressurized handgun applications to orchards/vineyards, 
Page 33 of 60

greenhouses, nurseries, landscaping, structural building components, typical-acreage field 

crops, and poultry houses

 1000 square feet (0.023 acres) for application to tree stumps (equivalent to approximately 

100 tree stumps each with a diameter of 4 feet)

 

Exposure Duration: 

HED typically 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 onemonth 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). 

Additionally, given that labels for boric acid and its sodium salts products generally do not 

specify retreatment intervals and its nature as a multi-use pesticide (as an insecticide, herbicide, 

and fungicide), it is not unreasonable to consider applicators handling this active ingredient 

relatively frequently. Thus, both short- and intermediate-term exposures are anticipated. 

However, the toxicological endpoint selected for the short-term assessment is protective of both 

short- and intermediate-term durations.

Mitigation/Personal Protective Equipment: 

Product labels vary with respect to work attire and levels of personal protective equipment, with 

some labels not providing any specifications to others requiring use of chemical/water-resistant 

gloves or respirators. 

As previously described, dermal toxicity was not identified so dermal risks are not quantified in 

this section. Dermal exposure-related work attire and PPE (e.g., chemical-resistant gloves) 

should therefore be considered in the context of end-use-product acute toxicity requirements.

Inhalation exposure is assessed assuming no respiratory protection and then, when risks of 

concern might indicate a need for them, assessed assuming different types of respirators. 

Respiratory protection requirements, beyond end-use-product acute toxicity requirements, should 

be considered for certain scenarios as described in this section. 

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.

Combining Exposures/Risk Estimates

As no dermal hazard was identified, there is no combination of dermal and inhalation exposures 

for risk assessment purposes.

Summary of Occupational Handler Non-Cancer Exposure and Risk Estimates
Page 34 of 60

The occupational handler exposure and risk estimates indicate the following scenarios have 

inhalation risk estimates of concern (MOEs < 100) without respiratory protection:

 Loading granules to support tractor-drawn spreader applications in industrial/commercial 

areas

 Applying granules to industrial/commercial areas via:

o Hand dispersal

o Tractor-drawn spreaders

o Spoons or cups

 Applying dusts with:

o Bulb dusters to food handling establishments, warehouses, residential living 

spaces, and structural building components

o Plunger dusters to structural building components

o Power dusters/blowers poultry houses

o Shaker cans to tree stumps

 Mixing/loading/applying liquid solutions with mechanically-pressurized handgun 

sprayers and airless sprayers to structural building components

 Mixing/loading dusts/powders with water and applying with:

o Mechanically pressurized handguns to poultry houses

o Manually pressurized handwands to residential living spaces and structural 

building components

Hand dispersal of granules in industrial/commercial areas and shaker can applications of dusts to 

tree stumps do not result in risk estimates of concern (MOE > 100) with a respirator that offers 

90% reduction in inhalation exposure (e.g., a half-face cartridge/canister style mask). All other

scenarios of concern without a respirator do not result in risk estimates of concern with a 

respirator that offers 80% reduction in inhalation exposure (e.g. a quarter-face dust/mist filtering 

face mask).

For the following two scenarios, inhalation exposures are of a magnitude that no standard 

respiratory protection12 reduces exposures to a level where inhalation risks are not of concern

(MOEs ≥ 100):

 Applying dusts with:

o Plunger dusters to structural building components and poultry houses

o Power dusters/blowers to poultry houses

Overall, application rates for boric acid/sodium salts products are relatively high – for the 

scenarios above, some on the order of 100 pounds of active ingredient or more per acre or almost 

1⁄2 pound of active ingredient per gallon of dilute solution. These high application rates, as well 

as, for applicable scenarios, the fact that exposure data indicates dust formulations present some 

of the highest inhalation exposures, is driving the presence of inhalation risks.

 

12 While a self-contained breathing apparatus or a powered-air supply respirator will likely sufficiently reduce 

exposures, it is assumed that these are infeasible/impractical options.
Page 35 of 60

Finally, all inhalation risk estimates – those of concern and not of concern – should be 

considered in concert with existing labels that require respirators under certain conditions as well 

as the default end-use product acute toxicity-based respiratory protection requirements. 

Table 8.1.1 presents detailed exposure and risk calculations.
Page 36 of 60

Table 8.1.1. Summary of Occupational Handler Risk Estimates for Boric Acid and its Sodium Salts

Exposure 

Scenario Crop / Target Category App Rate1

Amount 

Handled/Area 

Treated2

Inhalation3

Unit Exposure 

(ug/lb ai)4

Dose 

(mg/kg/day)5

MOE6

(LOC = 100)

Mixing /

loading / 

applying

liquids 

Backpack 

sprayer 

Nursery, Landscaping (turf, 

trees, plants) 0.000073 lb 

ai/gallon dilute 

solution

40 gallons dilute 

solution

69.1 2.5E-06 3,500,000

Greenhouse 140 5.1E-06 1,700,000

Structural Building 

Components

0.32 lb ai/gallon 

dilute solution 30 0.0048 1800

Manuallypressurized 

Handwand

Residential Living Spaces 0.15 lb ai/gallon 

dilute solution 1100 0.083 110

Nursery, Landscaping (turf, 

trees, plants), Greenhouse

0.000073 lb 

ai/gallon dilute 

solution

40 gallons dilute 

solution 30 1.1E-06 8,000,000

Mechanicallypressurized 

handgun

Field Crops (typicalacreage), Landscaping 

(trees, plants), Nursery, 

Orchards/vineyards

1000 gallons 

dilute solution

8.68 7.9E-06 1,100,000

Greenhouse 120 1.1E-04 80,000

Structural Building 

Components

0.32 lb ai/gallon 

dilute solution

79 (NR)

15.8 (PF5)

0.316 (NR)

0.063 (PF5)

28 (NR)

140 (PF5)

Landscaping (turf) 0.003 lb ai/acre 5 acres 1.9 3.6E-07 25,000,000

Airless sprayer

Structural Building 

Components

0.32 lb ai/gallon 

dilute solution

40 gallons dilute 

solution

560 (NR)

112 (PF5)

0.09 (NR)

0.018 (PF5)

98 (NR)

490 (PF5)

Brush/roller 280 0.045 200

Mixing / 

loading / 

applying 

Mechanicallypressurized 

handgun

Poultry house 0.15 lb ai/gallon 

dilute solution

1000 gallons 

dilute solution

79 (NR)

15.8 (PF5)

0.149 (NR)

0.03 (PF5)

59 (NR)

300 (PF5)
Page 37 of 60

Table 8.1.1. Summary of Occupational Handler Risk Estimates for Boric Acid and its Sodium Salts

Exposure 

Scenario Crop / Target Category App Rate1

Amount 

Handled/Area 

Treated2

Inhalation3

Unit Exposure 

(ug/lb ai)4

Dose 

(mg/kg/day)5

MOE6

(LOC = 100)

wettable 

dusts/ 

powders

Manuallypressurized 

Handwand

Residential Living Spaces 0.18 lb ai/gallon 

dilute solution 40 gallons dilute 

solution

1100 (NR)

220 (PF5)

0.099 (NR)

0.0198 (PF5)

89 (NR)

440 (PF5)

Structural building 

components

0.31 lb ai/gallon 

dilute solution

1100 (NR)

220 (PF5)

0.17 (NR)

0.0341 (PF5)

52 (NR)

260 (PF5)

Tree stumps 0.0023 lb ai/ft2 1,000 ft2 of tree 

stumps 30 0.00085 10,000

Loading/ 

applying 

dusts

Bulb duster

Crack and crevice

(residential areas, 

warehouses, food handling 

establishments)

0.00068 lb ai/ft2 10,000 ft2

1690 (NR)

338 (PF5)

0.144 (NR)

0.029 (PF5)

61 (NR)

310 (PF5)

0.22 lb ai/20 oz 

container

One 20 oz 

container 0.0047 1900

Plunger duster

Structural building 

components 0.0065 lb ai/ft2 10,000 ft2

1690 (NR)

338 (PF5)

169 (PF10)

1.38 (NR)

0.275 (PF5)

0.138 (PF10)

6.4 (NR)

32 (PF5)

64 (PF10)

Industrial/commercial areas 0.00068 lb ai/ft2 10,000 ft2 0.144 (NR)

0.029 (PF5)

61 (NR)

310 (PF5)

Poultry house 0.01 lb ai/ft2 10,000 ft2

2.18 (NR)

0.435 (PF5)

0.218 (PF10)

4 (NR)

20 (PF5)

40 (PF10)

Power 

duster/blower Poultry house 0.01 lb ai/ft2 10,000 ft2

17,500 (NR)

3500 (PF5)

17500 (PF10)

22.5 (NR)

4.5 (PF5)

2.25 (PF10)

< 1 (NR)

2 (PF5)

4 (PF10)

Shaker can

Greenhouse, Nursery, 

Landscaping 

(plants/flowers), 

Warehouse, Poultry house, 

Foundations/Perimeters

0.22 lb ai/20 oz 

container

One 20 oz 

container 17,500 (NR)

3500 (PF5)

17500 (PF10)

0.048 180

Tree stumps 0.0023 lb ai/ft2 1,000 ft2 of tree 

stumps

0.495 (NR)

0.099 (PF5)

0.05 (PF10)

18 (NR)

89 (PF5)

180 (PF10)
Page 38 of 60

Table 8.1.1. Summary of Occupational Handler Risk Estimates for Boric Acid and its Sodium Salts

Exposure 

Scenario Crop / Target Category App Rate1

Amount 

Handled/Area 

Treated2

Inhalation3

Unit Exposure 

(ug/lb ai)4

Dose 

(mg/kg/day)5

MOE6

(LOC = 100)

Mixing / 

loading 

liquids

Groundboom

Golf course (tees and 

greens)

0.0018 lb ai/acre

5 acres

0.219

2.5E-08 360,000,000

Golf course (fairways, tees, 

and greens), Field-grown 

ornamentals, 

Orchard/vineyards

40 acres 2.0E-07 44,000,000

Nursery, Greenhouse 60 acres 3.0E-07 30,000,000

Field crops (typical acreage) 80 acres 3.9E-07 22,000,000

Field crops (high acreage) 200 acres 9.9E-07 8,900,000

Airblast

Nursery 20 acres 9.9E-08 89,000,000

Orchards/vineyards 40 acres 2.0E-07 44,000,000

Applying 

sprays

Groundboom

Golf course (tees and 

greens)

0.0018 lb ai/acre

5 acres

0.34

3.8E-08 230,000,000

Golf course (fairways, tees, 

and greens), Field-grown 

ornamentals, 

Orchard/vineyards

40 acres 3.1E-07 29,000,000

Nursery, Greenhouse 60 acres 4.6E-07 19,000,000

Field crops (typical acreage) 80 acres 6.1E-07 14,000,000
Page 39 of 60

Table 8.1.1. Summary of Occupational Handler Risk Estimates for Boric Acid and its Sodium Salts

Exposure 

Scenario Crop / Target Category App Rate1

Amount 

Handled/Area 

Treated2

Inhalation3

Unit Exposure 

(ug/lb ai)4

Dose 

(mg/kg/day)5

MOE6

(LOC = 100)

Field crops (high acreage) 200 acres 1.5E-06 5,800,000

Airblast

Nursery 20 acres

4.71

2.1E-06 4,100,000

Orchards/vineyards 40 acres 4.2E-06 2,100,000

Mixing/ 

loading 

granules 

Tractor drawn 

spreader

Golf course (fairways, tees, 

and greens) 1.5 lb ai/acre 40 acres

1.7 (NR)

0.34 (PF5)

0.0013 6900

Industrial/commercial areas 105 lb ai/acre 60 acres 0.134 (NR)

0.027 (PF5)

66 (NR)

330 (PF5)

Applying 

granules/ 

baits

Hand dispersal

Residential areas, food 

handling establishments 0.017 lb ai/1000 ft2 10,000 ft2

470 (NR)

94 (PF5)

47 (PF10)

0.001 8500

Foundations/perimeters 1.5 lb ai/acre

1 acre

0.009 1000

Industrial/commercial areas 105 lb ai/acre

0.618 (NR)

0.123 (PF5)

0.062 (PF10)

14 NR)

72 (PF5)

140 (PF10)

Belly grinder

Landscaping (turf), 

Foundations/perimeters 1.5 lb ai/acre 1 acre

62

0.0012 7600

Industrial/commercial areas 105 lb ai/acre 1 acre 6.51 110

Tractor drawn 

spreader

Golf course (fairways, tees, 

and greens) 1.5 lb ai/acre 40 acres

1.2 (NR)

0.24 (PF5)

0.0009 9800

Industrial/commercial areas 105 lb ai/acre 60 acres 0.095 (NR)

0.019 (PF5)

93 (NR)

470 (PF5)
Page 40 of 60

Table 8.1.1. Summary of Occupational Handler Risk Estimates for Boric Acid and its Sodium Salts

Exposure 

Scenario Crop / Target Category App Rate1

Amount 

Handled/Area 

Treated2

Inhalation3

Unit Exposure 

(ug/lb ai)4

Dose 

(mg/kg/day)5

MOE6

(LOC = 100)

Rotary spreader

Golf course (fairways, tees, 

and greens), Landscaping 

(turf)

1.5 lb ai/acre 5 acres

10

0.0009 9400

Industrial/commercial areas 105 lb ai/acre 5 acres 0.066 130

Spoon

Foundations/perimeters 1.5 lb ai/acre 1 acre

121 (NR)

24.2 (PF5)

0.0023 3900

Industrial/commercial areas 105 lb ai/acre 1 acre 0.159 (NR)

0.032 (PF5)

55 (NR)

280 (PF5)

Cup

Foundations/perimeters 1.5 lb ai/acre 1 acre

12.5

0.00024 37000

Industrial/commercial areas 105 lb ai/acre 1 acre 0.0164 5400

Backpack Industrial/commercial areas 105 lb ai/acre 1 acre 23.8 0.031 280

Applying 

gels/pastes

Crack and crevice (residential areas, 

warehouses, food handling establishments) No exposure/risks expected from gel/paste formulations.

1 Based on registered label on registered labels outlined in Table 4.1. All rates expressed in terms of boron.

2 Exposure Science Advisory Council Policy #9.1 and information provided on labels

3 NR = no respirator; PF5 = “Protection Factor 5”, indicating a reduction in exposure of 80%; PF10 = “Protection Factor 10” indicating a reduction in exposure of 90%. Unless noted, results reflect no 

respirator (NR).

4 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (September 2015).

5 Inhalation Dose = Inhalation Unit Exposure (μg/lb ai) × Conversion Factor (0.001 mg/μg) × Application Rate (lb ai/acre) × Area Treated (A/day) ÷ BW (kg). Expressed in terms of boron.

6 Inhalation MOE = Inhalation POD (mg/kg/day) ÷ Inhalation Dose (mg/kg/day)
Page 41 of 60

8.2 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.

8.2.1 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.epa.gov/scipoly/sap/meetings/2009/120109meeting.html). 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-HQOPP-2014-0219). During Registration Review, the agency will utilize this analysis to determine 

if data (i.e., flux studies) or further analysis is required for boric acid/sodium salts.

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.

For applications within greenhouses, the Worker Protection Standard for Agricultural Pesticides 

contains requirements for protecting workers from inhalation exposures during and after 

greenhouse applications through the use of ventilation requirements [40 CFR 170.110, (3) 

(Restrictions associated with pesticide applications)]. Additionally, commercial applicators do 

not typically return to the treated areas after an indoor commercial pesticide application (sites 

such as warehouses, food handling establishments, and hotels, etc.) and thus an occupational 

post-application inhalation exposure assessment was not performed for commercial applicators.

8.2.2 Occupational Post-application Dermal Exposure/Risk Estimates

Dermal exposures are possible for workers re-entering treated areas (e.g., agricultural crops), 

however, as no systemic dermal toxicity was identified, occupational dermal risks are not of 

concern.
Page 42 of 60

Restricted-entry intervals (REIs) therefore default to technical grade active ingredient acute 

toxicity-based requirements. Currently, REIs on product labels vary considerably from 4 hours 

to 48 hours. These differences may reflect the different acute toxicity profiles of the various 

borate sodium salts, or the presence of an additional active ingredient in the product. REIs 

should be reconciled with the acute toxicity-based requirements.

Products having 4 hour REIs should be reviewed to be sure they meet certain criteria in 

accordance with the Pesticide Registration (PR) Notice 95-3 [Reduction of WPS Interim REIs 

for Certain Low Risk Pesticides]13. In PR Notice 95-3, there are a set of criteria listed for the 

active ingredient that must be met for chemicals to be eligible for a reduced REI. These criteria 

include:

1. The active ingredient is in Toxicity category III or IV based upon data for acute dermal 

toxicity, acute inhalation toxicity, primary skin irritation, and primary eye irritation. 

Acute oral toxicity data were used if no acute dermal data were available. If EPA lacked 

data on primary skin irritation, acute inhalation, or primary eye irritation of the active 

ingredient, the Agency reviewed data on that end-point for similar active ingredients 

(analogs), and excluded such active ingredients from consideration for the reduced REI, 

if the analog is in Toxicity Category I or II for that endpoint.

2. The active ingredient is not a dermal sensitizer (or in the case of biochemical and 

microbial active ingredients, no known reports of hypersensitivity exist).

3. The active ingredient is not a cholinesterase inhibitor (NMethyl carbamate and 

Organophosphate) as these chemicals are known to cause large numbers of pesticide 

poisonings and have the potential for serious neurological effects.

4. No known reproductive, developmental, carcinogenic, or neurotoxic effects have been 

associated with the active ingredient. If active ingredients did not have data available for 

these chronic health effects, EPA considered data on appropriate chemical and biological 

analogs. Active ingredients that have been classified as carcinogenic in Category B 

(probable human carcinogen) or Category C with a potency factor, Q* (possible human 

carcinogen, for which quantification of potential risk is considered appropriate), or are 

scheduled for the Health Effects Division's Cancer Peer Review process, were omitted 

from consideration.

5. EPA does not possess incident information (illness or injury reports) that are “definitely” 

or “probably” related to post-application exposures to the active ingredient.

Upon review of the criteria for boric acid and its sodium salts, it appears that they are not 

consistent with the criteria in PRN 95-3 that allow for a 4-hour REI, based primarily on the 

prevalence of acute toxicity category I for eye irritation. Note that similar criteria apply to the 

acute toxicity of the end-use products, but HED has only evaluated the 4 hour REI in the context 

of the acute toxicity of the active ingredients.

 

13 Available: http://www.epa.gov/PR_Notices/pr95-3.html
Page 43 of 60

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

RESIDENTIAL NON-CANCER HANDLER ALGORITHMS

Daily dermal and inhalation exposure (mg/day) for residential pesticide handlers, for a given 

formulation-application method combination, is estimated by multiplying the formulationapplication method-specific unit exposure by an estimate of the amount of active ingredient 

handled in a day, using the equation below:

E = UE * AR * A

where:

E = exposure (mg/day);

UE = unit exposure (mg/lb ai);

AR = application rate (e.g., lb ai/ft2, lb ai/gal); and

A = area treated or amount handled (e.g., ft2/day, gal/day).

Dermal and/or inhalation absorbed doses normalized to body weight are calculated as:

D = E *AF / BW

where:

D = dose (mg/kg-day);

E = exposure (mg/day);

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

BW = body weight (kg).

RESIDENTIAL NON-CANCER POST-APPLICATION ALGORITHMS

Post-application Dermal Exposure Algorithm – Physical Activities on Turf

Exposure resulting from contacting previously treated turf while performing physical activities is 

calculated as shown below. Residential post-application exposure assessment must include 

calculation of exposure on the day of application. Therefore, though an assessment can present 

exposures for any day “t” following the application, it must include “day 0” exposure.

E = TTRt * CF1 * TC * ET

where:

E = exposure (mg/day);

TTRt = turf transferable residue on day t (μg/cm2);

CF1 = weight unit conversion factor (0.001 mg/μg);

TC = transfer coefficient (cm2/hr); and
Page 44 of 60

ET = exposure time (hr/day).

If chemical-specific TTR data are available, then surface residues from the day of application 

should be used (assume that individuals could be exposed to residues immediately after 

application). However, if data are not available, then TTRt can be calculated using the following 

formula:

TTRt= AR * F * (1-FD)t * CF2 * CF3

where:

TTRt = turf transferable residue on day t (μg/cm2);

AR = application rate (lbs ai/ft2or lb ai/acre);

F = fraction of ai as transferable residue following application (unitless);

FD = fraction of residue that dissipates daily (unitless);

t = post-application day on which exposure is being assessed;

CF2 = weight unit conversion factor (4.54 x 108 μg/lb); and

CF3 = area unit conversion factor (1.08 x 10-3ft2/ cm2or 2.47 x 10-8acre/cm2).

Dermal absorbed doses are calculated as:

BW

E AF D*



where:

D = dose (mg/kg-day);

E = exposure (mg/day);

AF = absorption factor (dermal); and

BW = body weight (kg).

Table A-1: Turf (Physical Activities) -- Inputs for Residential Post-application Dermal Exposure

Algorithm Notation Exposure Factor

(units) Point Estimate(s)

AR Application rate

(mass active ingredient per unit area) [input]

F

Fraction of AR as TTR 

following application (if 

chemical-specific data is 

unavailable)

L/WP/WDG 0.01

Granules 0.002

FD

Daily residue dissipation 

(if chemical-specific data 

is unavailable)

(fraction)

L/WP/WDG 0.1

Granules 0.1

TC

Transfer 

Coefficient 

(cm2/hr)

L/WP/WDG

Adults 180,000

Children 1 < 2 years old 49,000

Granules

Adults 200,000

Children 1 < 2 years old 54,000
Page 45 of 60

Table A-1: Turf (Physical Activities) -- Inputs for Residential Post-application Dermal Exposure

Algorithm Notation Exposure Factor

(units) Point Estimate(s)

ET Exposure Time

(hours per day)

Adults 1.5

Children 1 < 2 years old 1.5

BW Body Weight

(kg)

Adults 80

Children 1 < 2 years old 11

L/WP/WDG = Liquids/Wettable Powders/Water-dispersible Granules

Post-application Hand-to-Mouth Exposure Algorithm– Physical Activities on Turf

Exposure from hand-to-mouth activity is calculated as follows (based on the algorithm utilized in 

the SHEDS-Multimedia model):

E = [HR * (FM * SAH) * (ET * N_Replen) * (1- (1- SE)

(Freq_HtM/N-Replen))]

where:

E = exposure (mg/day);

HR = hand residue loading (mg/cm2);

FM = fraction hand surface area mouthed / event (fraction/event);

SAH = typical surface area of one hand (cm2);

ET = exposure time (hr/day);

N_Replen = number of replenishment intervals per hour (intervals/hour);

SE = saliva extraction factor (i.e., mouthing removal efficiency); and

Freq_HtM = number of hand-to-mouth contacts events per hour (events/hour).

and

SA * 2

Fai *DE

HR

H

hands



where:

HR = hand residue loading (mg/cm2);

Faihands = fraction ai on hands compared to total surface residue from dermal transfer coefficient 

study (unitless);

DE = dermal exposure (mg); and

SAH = typical surface area of one hand (cm2).

Dose, normalized to body weight, is calculated as:

BW

E

D 

where:

D = dose (mg/kg-day);
Page 46 of 60

E = exposure (mg/day); and

BW = body weight (kg).

Table A-2: Turf (Physical Activities) – Inputs for Residential Post-application Hand-to-Mouth 

Exposure 

Algorithm 

Notation

Exposure Factor

(units) Point Estimate(s)

Faihands

Fraction of ai on hands 

from dermal transfer 

coefficient study

(unitless)

Liquid formulations 0.06

Granular formulations 0.027

DE Dermal exposure (mg) Calculated

SAH

Typical surface area of one hand (cm2), children 1 < 

2 years old 150

AR Application rate

(mass active ingredient per unit area) [input]

HR Residue available on the hands (mg/cm2) Calculated via (DE * Faihands)/SAH

FM

Fraction hand surface area mouthed

(fraction/event) 0.127

N_Replen Replenishment intervals per hour

(intervals/hr) 4

ET Exposure time 

(hrs/day) 1.5

SE Saliva extraction factor

(unitless) 0.48

Freq_HtM Hand-to-mouth events per hour

(events/hr) 13.9

BW Body Weight

(kg)

Children 1 < 2 years 

old 11

Post-application Object-to-Mouth Exposure Algorithm– Physical Activities on Turf

Exposure from object-to-mouth activity is calculated as follows (based on the algorithm utilized 

in SHEDS-Multimedia):

E = [OR* CF1 * SAMO * (ET * N_Replen) * (1- (1- SEO)

(Freq_OtM/N_Replen))]

where:

E = exposure (mg/day);

OR = chemical residue loading on the object on day “t” (ug/cm2);

CF1 = weight unit conversion factor (0.001 mg/μg);

SAMO = area of the object surface that is mouthed (cm2/event);

ET = exposure time (hr/day);

N_Replen = number of replenishment intervals per hour (intervals/hour);

SEO = saliva extraction factor (i.e., mouthing removal efficiency); and

Freq_OtM = number of object-to-mouth contact events per hour (events/hour).
Page 47 of 60

and

OR = AR * FO * CF2 * CF3

where:

OR = chemical residue loading on the object (μg/cm2);

AR = application rate (lbs ai/ft2or lb ai/acre);

FO = fraction of residue available on the object (unitless);

CF2 = weight unit conversion factor (4.54 x 108 μg/lb); and

CF3 = area unit conversion factor (1.08 x 10-3ft2/cm2or 2.47 x 10-8acre/cm2).

Dose, normalized to body weight, is calculated as:

BW

E

D 

where:

D = dose (mg/kg-day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A-3: Turf (Physical Activities) – Inputs for Residential Post-application Object-to-Mouth 

Exposure 

Algorithm 

Notation

Exposure Factor

(units) Point Estimate(s)

AR Application rate (to turf)

(mass active ingredient per unit area) [input]

FO Fraction of AR as OR following application 1 0.01

SAMO

Surface area of object mouthed 

(cm2/event) 10

N_Replen Replenishment intervals per hour (intervals/hour) 4

SEO

Saliva extraction factor

(fraction) 0.48

ET Exposure time 

(hours per day) 1.5

Freq_OtM Object-to-mouth events per hour (events/hr) 8.8

BW Body Weight (kg) Children 1 < 2 years old 11

1 This SOP assumes that all of the residue on the turf could be transferred to the object (e.g., object residue is 

equal to turf transferable residue).

Post-application Incidental Soil Ingestion Exposure Algorithm– Physical Activities on Turf

Exposure from incidental soil ingestion is calculated as follows:

E = SRt * SIgR * CF1

where:
Page 48 of 60

E = exposure (mg/day);

SRt = soil residue on day "t" (μg/g);

SIgR = ingestion rate of soil (mg/day); and

CF1 = weight unit conversion factor (1 x 10-6g/μg).

and

SRt = AR * FS * (1-FD)

t

* CF2 * CF3 * CF4

where:

SRt = soil residue on day "t" (μg/g);

AR = application rate (lbs ai/ft2or lb ai/acre);

FS = fraction of ai available in uppermost cm of soil (fraction/cm);

FD = fraction of residue that dissipates daily (unitless);

T = post-application day on which exposure is being assessed;

CF2 = weight unit conversion factor (4.54 x 108 μg/lb);

CF3 = area unit conversion factor (1.08 x 10-3ft2/cm2 or 2.47 x 10-8acre/cm2); and

CF4 = soil volume to weight unit conversion factor (0.67 cm3/g soil).

Dose, normalized to body weight, are calculated as:

BW

E

D 

where:

D = dose (mg/kg-day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A-4: Turf (Physical Activities) – Inputs for Residential Post-application Incidental Soil Ingestion 

Exposure 

Algorithm 

Notation

Exposure Factor

(units) Point Estimate(s)

AR Application rate

(mass active ingredient per unit area) [input]

FS Fraction of AR available in uppermost 1 cm of soil

(unitless) 1

FD

Daily residue dissipation

(fraction) 0.1

SIgR Soil ingestion rate (mg/day) 50

BW Body weight (kg) Children 1 < 2 years old 11

Post-application Episodic Granular Ingestion Exposure Algorithm– Physical Activities on Turf

Exposure from incidental ingestion of pesticide pellets or granules is calculated as follows:
Page 49 of 60

 E = GIgR* FD * CF1

where:

E = exposure (mg/day);

GIgR = ingestion rate of dry pesticide formulation (g/day);

FD = fraction of ai in dry formulation (unitless); and

CF1 = weight unit conversion factor (1,000 mg/g).

Dose, normalized to body weight, are calculated as:

BW

E

D 

where:

D = dose (mg/kg-day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A-5: Turf (Physical Activities) – Inputs for Residential Post-application Episodic Granular 

Ingestion Exposure 

Algorithm 

Notation

Exposure Factor 

(units) Point Estimate(s)

FD Fraction of active ingredient in dry formulation [input]

AR Application rate (lbs/A or lbs/1,000 ft2) [input]

GIgR Granule ingestion rate per day

(g/day) 1 0.3

BW Body Weight (kg) Children 1 < 2 years old 11

1 See discussion below on how this value may be adjusted if product specific information is available.

Turf/Mowing

Post-application Dermal Exposure Algorithm – Mowing

Exposure resulting from contacting previously treated turf while mowing is calculated as 

follows:

E = TTRt * CF1 * TC * ET

where:

E = exposure (mg/day);

TTRt = turf transferable residue on day "t" (μg/cm2);

CF1 = weight unit conversion factor (0.001 mg/μg);

TC = transfer coefficient (cm2/hr); and

ET = exposure time (hr/day).

and
Page 50 of 60

TTRt = AR * FAR * (1-FD)

t

* CF2 * CF3

where:

TTRt = turf transferable residue on day "t" (μg/cm2);

AR = application rate (lbs ai/ft2or lb ai/acre);

FAR = fraction of ai retained on turf (unitless);

FD = fraction of residue that dissipates daily (unitless);

t = post-application day on which exposure is being assessed;

CF2= weight unit conversion factor (4.54 x 108 μg/lb); and

CF3 = area unit conversion factor (1.08 x 10-3ft2/cm2or 2.47 x 10-8acre/cm2).

Absorbed dose, normalized to body weight, are calculated as:

BW

E AF D*



where:

D = dose (mg/kg-day);

E = exposure (mg/day); 

AF = absorption factor (dermal); and

BW = body weight (kg).

Table A-6: Turf (Mowing) – Inputs for Residential Post-application Dermal Exposure 

Algorithm Notation Exposure Factor

(units) Point Estimate(s)

AR Application rate

mass active ingredient per unit area [input]

FAR

Fraction of AR as 

TTR following 

application

L/WP/WDG 0.01

Granules 0.002

FD

Daily residue 

dissipation

L/WP/WDG 0.1

Granules 0.1

TC Transfer Coefficient

(cm2/hr)

Adult 5,500

Children 11 < 16 years 

old 4,500

ET Exposure time 

(hours per day) 1

BW Body Weight 

(kg)

Adults 80

Children 11 < 16 years 

old 57

L/WP/WDG = liquid/wettable powder/water dispersible granule

Post-Application Inhalation Exposure Algorithms
Page 51 of 60

Exposure to pesticide vapors 

The following algorithm is used to determine post-application inhalation exposure from indoor 

surface-directed sprays:

E =

IR ∗ Mlabel

ACH ∗ Vroom [1 − (

(ACH ∗ e

−k∗ET) − (k ∗ e−ACH∗ET

ACH − k

)]

where:

E = exposure (mg/day);

IR = inhalation rate (m3/hr);

Mlabel = mass of active ingredient applied, determined from product label (mg);

Vroom = volume of room (m3);

ACH = air exchanges per hour (1/hr);

k = first order decay rate (1/hr); and

ET = exposure time (hr).

In the above equation, a mass of pesticide is applied to a surface and the emission of the 

pesticide from the surface is assumed to decline over time due to dissipation of the pesticide (i.e., 

emission from the treated surface and removal due to the air exchange rate). The mass of active 

ingredient applied can be calculated using the following formula:

Mlabel = AR ∗ A ∗ CF1

where:

Mlabel = mass of active ingredient applied, determined from product label (mg);

AR = application rate (e.g., lb ai/ft2, lb ai/gal); 

A = area treated or amount handled (e.g., ft2/day, gal/day); and

CF1 = conversion factor (4.54x105 mg/lb).

The exposure equation models an emission rate that decreases over time, which is based on a 

first-order decay rate constant (k). Evans (1994) proposed calculating such a decay rate based on 

work done by Chinn (1981). Chinn developed the following relationship between the volatility, 

or saturation concentration (Csat), of a chemical and the time required for 90% of the chemical to 

evaporate (EvapT): 

EvapT = 10[7.3698−0.9546∗ log10(Csat)]

where:

EvapT = evaporation time (sec); and

Csat = saturation concentration (mg/m3).
Page 52 of 60

Evans proposed the following equation to calculate the decay rate (or dissipation rate) that 

defines the change in the emission rate based on the evaporation time described by Chinn:

k =

ln(0.1) ∗ CF1

EvapT

where:

k = first order decay rate (1/hr),

CF1 = conversion factor (sec/hr), and

EvapT = evaporation time (sec).

**Saturation concentration verification**

In the vapor emission assessment, post-application inhalation exposure occurs from the release 

of vapors following a surface treatment indoors. The concentration of pesticide in the air is 

modeled over time to calculate exposure. The maximum concentration allowed in the air 

should be the saturation concentration, calculated as a function of the pesticide’s molecular 

weight and vapor pressure. The equation used to model the air concentration is not bound 

by the saturation concentration; therefore, the reviewer must perform a check to make 

sure the exposures being calculated are valid. 

The exposure equation above is based on the mass of pesticide applied, not the concentration of 

the pesticide in the air; therefore, the reviewer must check that the input for mass applied (Mlabel) 

is predicting an air concentration less than or equal to the saturation concentration. The 

following equation can be used to calculate the theoretical mass applied that would result in an 

air concentration that reaches the saturation concentration for a pesticide (MCsat): 

MCsat =

Csat ∗ (ACH − k) ∗ V

k

MCsat should be compared to Mlabel. 

 If Mlabel > MCsat  Mlabel will predict an air concentration higher than the saturation 

concentration. Use MCsat in the exposure calculation. 

 If Mlabel < MCsat,  Mlabel will not predict an air concentration higher than the saturation 

concentration. Use Mlabel in the exposure calculation. 

Once the post-application inhalation exposure is calculated, the inhalation dose normalized to 

body weight is calculated as:

D =

E ∗ AF

BW
Page 53 of 60

where:

D = dose (mg/kg-day);

E = exposure (mg/day);

AF = absorption factor (inhalation); and

BW = body weight (kg).

Table A-7: Indoor Environments – Inputs for Residential Post-application Inhalation Exposure 

Algorithm 

Notation

Exposure Factor

(units) Point Estimate(s)

Generic Variables Used in Calculating Post-application Inhalation Exposure

IR Inhalation rate 

(m3/hour)

Adult 0.64

Children 1 < 2 years old 0.33

ACH Air changes per hour 

(hr-1)

0.45

BW Body weight

(kg)

Adult 80

Children 1 < 2 years old 11

Vroom

Volume of room 

(m3)

33

Variables Specific to Post-application Inhalation Exposure to Pesticide Aerosols

Co

Initial air concentration

(mg/m3)

Calculated; concentration at 

time “0”

AR Application rate

(lb ai/ ft3)

[input]

A.I. Percent ai in product

(%) [input]

Vproduct

Volume of product

(mL) [input]

Dproduct

Product density

(g/mL)

Water-based products 1

Solvent-based products 0.8

ET Exposure time 

(hr/day) 2

Variables Specific to Post-application Inhalation Exposure to Pesticide Vapors

Csat

Saturation concentration

(mg/m3)

Calculated

VP Vapor pressure 

(mmHg) [input]

MW Molecular weight 

(g/mol) [input]

R

Gas constant 

(L-atm/mol-K) 0.0821 

T

Temperature of the air

(kelvin, K) 298

Mlabel

Mass of active ingredient applied 

(mg) [input]

k First order decay rate Calculated

ET Exposure time 

(hr/day)

Adult 16

Children 1 < 2 years old 18
Page 54 of 60

Post-Application Dermal Exposure Algorithm (hard surfaces and carpets)

The algorithm to calculate exposure is as follows:

E = TR ∗ TC ∗ ET ∗ CF1

where:

E = exposure (mg/day);

TR = indoor surface transferable residue (μg/cm2);

TC = transfer coefficient (cm2/hr); 

ET = exposure time (hr/day); and

CF1 = conversion factor (0.001 mg/μg).

If chemical-specific TR data are available, this is preferred and should be used to calculate 

exposure. However, if chemical-specific TR data are not available, then TR can be calculated 

using the following formula:

TR = DepR ∗ Fai

where:

TR = indoor surface transferable residue (μg/cm2);

DepR = deposited residue (g/cm2), based on (in order of preference):

(1) Chemical-specific residue deposition data (g/cm2),

(2) Application rate (lb ai/area), or

(3) Default residue based on type of application (g/cm2); and

Fai = fraction of ai available for transfer from carpet or hard surface (unitless).

Absorbed dermal dose, normalized to body weight, are calculated as:

D =

E ∗ AF

BW

where:

D = dose (mg/kg-day);

E = exposure (mg/day);

AF = absorption factor; and

BW = body weight (kg).

Table A-8: Indoor Environments (Hard Surfaces and Carpets) – Inputs for Residential Post-application

Dermal Exposure 

Algorithm 

Notation

Exposure Factor

(units) Point Estimate(s)

TR Transferable residue

(g/cm2)

(1) Chemical-specific transferable 

residue data OR
Page 55 of 60

Table A-8: Indoor Environments (Hard Surfaces and Carpets) – Inputs for Residential Post-application

Dermal Exposure 

Algorithm 

Notation

Exposure Factor

(units) Point Estimate(s)

(2) Estimated: DepR * Fai

DepR Deposited residue

(g/cm2)

(1) Chemical-specific residue 

deposition data,

(2) Estimated based on application 

rate, or 

(3) Estimated based on default 

residue related to type of application

Fai

Fraction of DepR as TR 

following application

Carpets 0.06

Hard surfaces 0.08

TC Transfer Coefficient

(cm2/hr)

Adult 6,800

Children 1 < 2 years old 1,800

ET Exposure Time (hrs/day)

Adults

Carpets 8

Hard 

Surfaces 2

Children 1 < 2 

years old

Carpets 4

Hard 

Surfaces 2

BW Body weight (kg) Adult 80

Children 1 < 2 years old 11

Post-Application Dermal Exposure Algorithm (mattresses)

The algorithm to calculate absorbed dose is as follows:

D = DR ∗

SA

BW ∗ F ∗ Fai ∗ PF ∗ AF ∗ CF1

where:

D = Dermal dose (mg/kg-day);

DR = Deposited residue (mg/cm2);

SA/BW = Surface area / Body Weight Ratio (cm2/kg);

F = Fraction of body that contacts residue;

CF1 = Conversion factor (mg/g);

AF = Absorption factor;

Fai = fraction of ai available for transfer from treated mattress; and

PF = Protection factor to account for the presence of a single layer of 

fabric (e.g. bed sheet) between the treated material and individual.
Page 56 of 60

Table A-9: Indoor Environments (mattresses) – Inputs for Residential Post-application Dermal Exposure

Algorithm

Notation

Exposure Factor

(units) Point Estimate(s)

DR Deposited residue

(g/cm2)

(1) Calculated based on information provided on 

label

OR

(2) based on default residue values

SA/BW

Surface area / Body Weight 

Ratio

(cm2/kg)

Adult 280

Children 1 < 2 

years old 640

F Fraction of body that contacts residue 0.5

Fai Fraction of DR available for transfer 0.06

PF Protection Factor 0.5

Post-application Hand-to-Mouth Exposure Algorithm

Exposure from hand-to-mouth activity is calculated as follows (based on algorithm utilized in 

SHEDS-Multimedia):

E = [HR ∗ (FM ∗ SAH) ∗ (ET ∗ N_Replen) ∗ (1 − (1 − SE)

Freq_HtM

N_Replen )]

where:

E = exposure (mg/day);

HR = hand residue loading (mg/cm2);

FM = fraction hand surface area mouthed / event (fraction/event);

ET = exposure time (hr/day);

SAH = surface area of one hand (cm2);

N_Replen = number of replenishment intervals per hour (intervals/hour);

SE = saliva extraction factor (i.e., mouthing removal efficiency); and

Freq_HtM = number of hand-to-mouth contacts events per hour (events/hour).

and

HR =

Faihands ∗ DE

SAH ∗ 2

where:

HR = hand residue loading (mg/cm2);

Faihands = fraction ai on hands compared to total surface residue from jazzercise 

study (unitless);

DE = dermal exposure (mg); and
Page 57 of 60

SAH = typical surface area of one hand (cm2).

and

Dose, normalized to body weight, is calculated as:

D =

E

BW

where:

D = dose (mg/kg-day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A-10: Indoor Environments – Inputs for Residential Post-application Hand-to-Mouth Exposure 

Algorithm 

Notation

Exposure Factor

(units) Point Estimate(s)

Faihands

Fraction of ai on hands from jazzercise study

(unitless) 0.15

DE Dermal exposure

(mg) Calculated

HR Residue available on the hands 

(mg/cm2)

Calculated

SAH

Surface area of one hand 

(cm2)

Children 1 < 2 years old 150

AR Application rate

(mass active ingredient per unit area) [input]

FM

Fraction of hand mouthed per event 

(fraction/event) 0.13

N_Replen Replenishment intervals per hour

(intervals/hr) 4

ET Exposure time

(hours per day)

Children 1 < 2 

years old

Carpets 4

Hard Surfaces 2

SE Saliva extraction factor

(fraction) 0.48

Freq_HtM

Hand-to-mouth events 

per hour

(events/hr)

Children 1 < 2 years old 20

BW Body Weight

(kg) Children 1 < 2 years old 11
Page 58 of 60

Post-application Object-to-Mouth Exposure Algorithm

Exposure from object-to-mouth activity is calculated as follows (based on algorithm utilized in 

SHEDS-Multimedia):

E = OR ∗ CF1 ∗ SAMO ∗ (ET ∗ N_Replen) ∗ (1 − (1 − SE)

Freq_OtM

N_Replen )

where:

E = exposure (mg/day);

OR = chemical residue loading on an object (g/cm2);

CF1 = weight unit conversion factor (0.001 mg/g);

SAMO = area of the object surface that is mouthed (cm2/event);

ET = exposure time (hr/day);

N_Replen = number of replenishment intervals per hour (intervals/hour);

SE = saliva extraction factor (i.e., mouthing removal efficiency); and

Freq_OtM = number of object-to-mouth contact events per hour (events/hour).

and

OR = DepR ∗ FO

where:

OR = chemical residue loading on the object (μg/cm2);

DepR = deposited residue (μg/cm2); and

FO = fraction of residue transferred to an object (unitless).

and

Oral dose, normalized to body weight, is calculated as:

D =

E

BW

where:

D = dose (mg/kg-day);

E = exposure (mg/day); and

BW = body weight (kg).
Page 59 of 60

Table A-11: Indoor Environments – Inputs for Residential Post-application Object-to-Mouth Exposure

Algorithm 

Notation

Exposure Factor

(units) Point Estimate(s)

AR Application rate

(mass active ingredient per unit area) [input]

FO

Fraction of residue 

transferred to an 

object

Carpets 0.06

Hard surfaces 0.08

SAMO

Surface area of object mouthed

(cm2/event) 10

N_Replen Replenishment intervals per hour

(intervals/hour) 4

SEO Saliva extraction factor 0.48

ET Exposure Time

(hours per day)

Children 1 < 

2 years old

Carpets 4

Hard Surfaces 2

Freq_OtM

Object-to-mouth events 

per hour

(events/hour)

Children 1 < 2 years old 14

BW Body Weight

(kg) Children 1 < 2 years old 11

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 registered labels (lb ai A, lb ai/gal, etc.), 

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:
Page 60 of 60

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 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).