A1-1

Appendix 1. Pyrethroid Studies Evaluated for Endpoint Selection

Pyrethroid (PC Code) MRID Study Route of 

Administration Doses (mg/kg) Species

LOAEL*

(mg/kg) Endpoints

Allethrin; S-Bioallethrin

(004001)

44517801 Acute gavage (1% 

CMC), 10 ml/kg

0, 5, 30, 90 rat 90 neurotoxicity including hunched 

posture, head and/or body twitches, 

tremor, abnormal gait, increased body 

temperature, and decreased hindlimb 

and forelimb grip strength in females

43343301 Acute gavage (corn 

oil) 10 ml/kg

0, 30, 100, 300 rat 300 reduced motor activity in both sexes,

transient muscle tremors, and death in 

females

43694501 Subchronic dietary admix 0, 9.3, 74, 363 

(M); 0, 11.1, 

88, 420 (F)

rat 363 decreases in mean bodyweight and food 

consumption; No indications of 

neuropathology

46582501 Subchronic dietary admix 0, 5, 18.1, 144, 

452 

rat 452 decreases in body weight, body weight 

gain, and food conversion in both sexes; 

No indications of neurotoxicity

Bifenthrin (128825) 44862101 Subchronic dietary admix 0, 2.5, 5, 10B

(0, 50, 100, 

200 ppm)

rat >10 LOAEL – Not Observed

44862102 Acute gavage ( no 

vehicle; actual 

volumes 0.063 

water, 0.0084, 

0.0294, and 

0.063 ml/kg 

BW)

0, 10, 35, 75 rat 75 clinical and FOB findings and differences 

in motor activity, and mortality

44862103 Acute Dietary Admix 0, 2.97, 6.0, 

11.8

rat 6.0 neuromuscular findings including 

tremors, changes in grip strength and 

landing foot-splay
Appendix 1. Toxicity Data for Screening Level Cumulative Risk Assessment

A1-2

Pyrethroid (PC Code) MRID Study Route of 

Administration Doses (mg/kg) Species

LOAEL*

(mg/kg) Endpoints

46750501 DNT dietary admix 0, 3.6, 7.2, 9.0 

pre-lactation; 

0, 8.3, 16.2, 

20.7 during 

lactation

rat Maternal: 7.2

Offspring: 7.2

Maternal: clinical signs of neurotoxicity 

(tremors, clonic convulsions, and 

increased grooming counts)

Offspring: clinical signs of neurotoxicity 

(excessive grooming)

00141199 Subchronic dietary admix 0, 1, 4, 8, 15 rat 8 increased incidence of tremors in both 

sexes

00141200 Subchronic capsules 0, 2.2, 4.4, 8.8, 

17.7

Dog 4.4 increased incidence of tremors in both 

sexes

00163065 Chronic capsules 0, 0.66, 1.3, 

2.7, 4.4 

Dog 2.7 increased incidence of tremors in both 

sexes

46750501 DNT dietary admix 0, 3.6, 7.2, 9 rat Maternal: 3.6

Offspring: 7.2

Maternal: tremors

Offspring clinical signs of neurotoxicity 

including tremors, clonic convulsions, 

and increased grooming counts

Cyfluthrin, betacyfluthrin (128831)00157801 Acute gavage (PEG 

400)

0, 50, 60 rat <50 non-specific disturbed behavior, rolling, 

tremors, stretched gait, uncoordinated 

gait, and salivation

00157802 Acute gavage (2% 

aqueous 

cremophor EL)

0.01, 0.03, 0.1, 

0.3, 1, 5

rat 0.1 based on ability to maintain stationary 

posture

00157887 Acute gavage (PEG 

400)

0, 40, 80 rat 80 startled gait, slow leg movement, and 

titubation

44296001 Subchronic dietary admix 0, 2.02, 7.99, 

26.81 

rat 26.81 clinical signs, changes in FOB 

parameters and possibly decreased 

body weights, body weight gains, and 

food consumption

44401101 Acute gavage (1% 

Cremophor EL)

0, 0.5, 2, 10 rat 10 clinical signs, changes in FOB 

parameters and decreases in motor 

activity
Appendix 1. Toxicity Data for Screening Level Cumulative Risk Assessment

A1-3

Pyrethroid (PC Code) MRID Study Route of 

Administration Doses (mg/kg) Species

LOAEL*

(mg/kg) Endpoints

46054101 DNT dietary admix Gestation; 0, 

2.4, 11.0, and 

17.8 

mg/kg/day: 

lactation-0, 

5.9, 25.4, and 

40.9 

mg/kg/day 

rat Maternal: 

>17.8

Offspring: 

17.8

Maternal: LOAEL not established; 

Offspring: decreased body weight gain 

and decreased brain weights in females 

at termination

47033001 Subchronic dietary admix 0, 3.07, 12.5, 

49.1

rat 49.1 decreased food consumption, body 

weight and body gain

00131530 Chronic dietary admix 0, 1.6, 5, 15B

(converted 

from ppm)

dog 15 hind limb abnormalities such as stiff 

gait, incoordination, arching backs

00151358 Chronic dietary admix 0, 1, 4, 16 

(converted 

from ppm)

dog 16 ataxia in 2 dogs on one occasion each

41267801 Subchronic dietary admix 0, 0.39, 2.36, 

13.9

dog 13.9 gait abnormalities, increased incidence 

of vomiting, and suggestive decreased 

body weight gain

44435401 Chronic corn oil/diet 0, 1.36, 2.43, 

10.64, 15.47 

dog 10.64 clinical signs, gait abnormalities, and 

abnormal postural reactions in males 

and females

lambda-cyhalothrin

(128897, 128867)

44861510 Acute gavage (corn 

oil, 1ml/100g 

BW)

0, 2.5, 10, 35 rat 35 clinical signs of toxicity and FOB 

parameters

45689101 

(43013301 

through 05)

Subchronic Dietary Admix 0, 2.0, 4.6, 

11.4

rat >11.4 LOAEL - not observed

00154795 Subchronic capsules (corn 

oil)

0, 1, 205, 10 dog 2.5 LOAEL- 2.5 mg/kg/d based on an 

increase in incidence of liquid feces

40027902 Chronic capsules (corn 

oil)

0, 0.1, 0.5, 3.5 dog 0.5 clinical signs of neurotoxicity (gait 

abnormalities, convulsions)
Appendix 1. Toxicity Data for Screening Level Cumulative Risk Assessment

A1-4

Pyrethroid (PC Code) MRID Study Route of 

Administration Doses (mg/kg) Species

LOAEL*

(mg/kg) Endpoints

46449102 DNT Dietary Admix Gestation -0, 

1.8, 4.3, 10.0; 

Lactation - 0, 

4.0, 9.4, 23.1 

rat Maternal: 

10;

Offspring: 

NA

Maternal: decreased body weight, 

body weight gain, and food 

consumption; 

Offspring LOAEL/NOAEL not determined 

due to lack of brain morphometrics at 

low and mid doses, inadequate 

assessments of auditory startle 

response in PND 61 females and motor 

activity

None, data 

provided 

Pytech 

Chemicals 

Gmbh Inc.

Acute Dietary Admix 0, 0.22, 0.85, 

4.2, 8.81 

rat 8.81 decreased body weight gain and 

neurotoxic effects (incoordination, 

abnormal posture, flaccid musculature)

Cypermethrin; zetacypermethrin; betacypermethrin (109702, 

129064)

, 

43152001 Acute Gavage (Corn 

Oil )

0, 30, 100, 200 

mg/kg

rat 100 ataxia and related conditions

43152002 Subchronic Dietary Admix 0, 31, 77, 102 rat 77 Males - decreased body weight gain, 

and increased landing foot splay: 

Females - ataxia, splayed hindlimbs, 

impaired gait and decreased body 

weight gain

46449102 DNT Dietary Admix Gestation-0, 

1.8, 4.3, and 

10.0: 

Lactation-0, 

4.0, 9.4, and 

23.1

rat Maternal: 

10.0

Offspring: 

>10

Maternal: decreased body weight, body 

weight gain, and food consumption;

Offspring-LOAEL not observed
Appendix 1. Toxicity Data for Screening Level Cumulative Risk Assessment

A1-5

Pyrethroid (PC Code) MRID Study Route of 

Administration Doses (mg/kg) Species

LOAEL*

(mg/kg) Endpoints

46670402 DNT Dietary Admix Gestation-0, 0, 

2.9, 7.4, or 

17.3 : 

Lactation-0, 

7.1, 17.5, and 

39.8

rat Maternal: 

>17.3

Offspring: 

17.4

Maternal: LOAEL-Not established; 

Offspring: decreased body weights and 

body weight gains in females, altered 

motor activity in males and females, 

and changes in brain morphometrics

44962201 Acute Gavage 

(undiluted)

0, 10, 50, 250 

mg/kg

rat LOAEL - 50 mg/kg based on clinical signs 

of toxicity and FOB findings; NOAEL - 10 

mg/kg

44962202 Subchronic Dietary Admix 0, 5.0, 26.3, 

47.2

rat 26.3 decreased motor activity increased 

landing foot splay, decreased body 

weights, body weight gains and food 

consumption in males

45657401 Acute Gavage (Corn 

Oil, 1 ml/kg)

0, 20, 60, 

100/120

rat <20 decreased motor activity and gait 

abnormalities

00112909/ 

42068503/ 

92027037

Chronic capsule (corn 

oil)

0, 1, 5, 15 dog 5 gastrointestinal effects (liquid stool)

00112929/

42068502

Subchronic Dietary Admix 0, 0.13, 1.25, 

12.5, 37.5

dog 37.5 clinical signs (whole body tremors, 

exaggerated gait, ataxia, incoordination, 

hyperaesthesia, licking & chewing of 

paws; diarrhea, anorexia) & decreased 

body wt

44527002 Subchronic Dietary Admix 0, 10.4, 20.7, 

24.6, 37.0

dog 37.0 tremor activity in both sexes and 

decreased body weight and body weight 

gains in the males and females

44536801 Chronic Dietary Admix 0, 2.9, 6.0, 

20.4, 33.9 

dog 20.4 mortality (1 male) and abnormal clinical 

signs in males (irregular gait, excessive 

salivation, tremors), and decreased 

body weights and body weight gains in 

females

Cyphenothrin (129013) 00155352/ 

42681112)

Subchronic Dietary Admix 0, 5.6, 16.8, 

56.4

rat >56.4 LOAEL-Not observed
Appendix 1. Toxicity Data for Screening Level Cumulative Risk Assessment

A1-6

Pyrethroid (PC Code) MRID Study Route of 

Administration Doses (mg/kg) Species

LOAEL*

(mg/kg) Endpoints

42706903 Chronic capsule 0, 3, 10, 60 dog 30 clinical signs of toxicity, such as 

tremors, reddish/pale mucosa, and 

emesis

42717503 Subchronic capsule 0, 1, 3, 10, 30 dog 30 clinical signs of toxicity (emesis, tremor, 

reddish/pale mucosa)

42706904/ 

42826003

Chronic Dietary Admix 0, 4.8, 14.5, 

48.2 

rat >48.2 LOAEL-Not observed 

Deltamethrin (097805) 44557901 Acute Gavage (Corn 

Oil, 5 ml/kg)

0, 5, 15, 50 

mg/kg

rat 15 salivation, soiled fur, impaired mobility, 

and no reaction to approach or touch 

response

46814301 DNT Dietary Admix 0, 1.64, 6.78, 

16.1 

rat Maternal: 

16.1

Offspring: 

16.1

Maternal: decreased body weight, 

body weight gain, and food 

consumption

Offspring: decreased body weight and 

body weight gain during pre- and postweaning, increased incidence of 

vocalizations (males) during FOB 

handling, and decreased fixed brain 

weight in females

44557902 Subchronic Dietary Admix 0, 4, 14, 54 rat 54 mortality, clinical signs of toxicity, FOB 

findings, decreased body weights, body 

weight gains and food consumption

00098104 Subchronic capsule (PEG 

200)

0, 0.1, 1, 2.5, 

10

dog 2.5 CNS effects, vomiting, diarrhea, and 

decreased body weight gains of treated 

male and female dogs

Esfenvalerate (109301) 45228301 Acute Gavage (Corn 

Oil, 10 ml/kg)

0, 1.75, 1.90 

20, 80

rat 1.9 Tremors in females (tremors observed 

in males at 20 mg/kg/day)

45157501 Subchronic Dietary Admix 0, 3.22, 6.39, 

20.8

rat 6.39 reduced forelimb grip strength and 

superficial skin wounds in male rats
Appendix 1. Toxicity Data for Screening Level Cumulative Risk Assessment

A1-7

Pyrethroid (PC Code) MRID Study Route of 

Administration Doses (mg/kg) Species

LOAEL*

(mg/kg) Endpoints

45202301 Subchronic Dietary Admix 0, 3, 8.9, 28.8 rat 8.9 decreased body weight and body 

weight gain in males and decreased

motor activity in females

00151030 Subchronic Dietary Admix 0, 2.5, 7.5, 15, 

25B

rat 7.5 neurologic dysfunction ("jerky leg 

movements)

40215601 Subchronic Dietary Admix 0, 3.8, 5, 6.3, 

15B

rat 15 decreased body weight gains and 

clinical signs of neurologic dysfunction 

(hyperactivity and “jerky leg 

movements”) in both sexes

00163855 Subchronic Dietary Admix 0, 0.63, 1.3, 5 dog 7.5 (rangefinding study)decreased body weights in both sexes 

and ataxia in one male during week 3

41637801 Acute Gavage (Corn 

Oil, 5ml/kg)

Esfen (5, 20, 

360); 

Fenvalerate 

(20, 80, 360)

rat Esfen: 20

Fenvalerate: 

80

Esfen: muscular fibrillation, salivation 

and ataxia

Fenvalerate: muscular fibrillation

Fenpropathrin (127901) 00127362 Subchronic Dietary Admix 0, 0.1, 0.5, 2.5, 

12.5B

rat >12.5 LOAEL-Not observed

00127363 Subchronic Dietary Admix 0, 0.2, 1.5, 5, 

15, 30B

(0, 3, 30, 100, 

300, 600 ppm)

rat 30 blood chemistry (14% decrease in 

kaolin-cephalin clotting time), increased 

brain and kidney weights

00127364 Subchronic Dietary Admix 0, 6.25, 12.5, 

18.75B

(0, 250, 500, 

750 ppm)

Dog 12.5 tremors and decreased BWG
Appendix 1. Toxicity Data for Screening Level Cumulative Risk Assessment

A1-8

Pyrethroid (PC Code) MRID Study Route of 

Administration Doses (mg/kg) Species

LOAEL*

(mg/kg) Endpoints

00126827 Chronic Dietary Admix 0, 0.05, 0.25, 

1.25, 6.25, 25B

(0, 1, 5, 25, 

125, 500 ppm)

rat 6.25 decreased body weight gain

00143130 Chronic Dietary Admix 0, 2.5, 6.25, 

18.75B

(0, 100, 250, 

750 ppm)

Dog 6.25 tremors and soft stool

473745605 Acute gavage, corn 

oil, 5 mL/kg

0, 3, 6, 15, 30 rat 30 slight tremors and clonic convulsions

47345607 Subchronic Dietary Admix 0, 4, 13, 38 rat 38 tremors, convulsions, impaired gait, and 

related FOB findings predominantly in 

the females

47345609 DNT Dietary Admix Gestation-0, 3, 

8, 19; 

Lactation-0, 7, 

16, 40

rat Maternal: 19

Offspring: 19

Maternal: tremors during lactation;

Offspring: decreased BWG during preweaning period and increased 

maximum startle response amplitude in 

females and decreased brain weights in 

males

Fluvalinate, tau

(109302)

43433901 Acute Gavage (corn 

oil, 10 ml/kg)

0, 10, 60, 100 rat 60 clinical signs of toxicity (decreased body 

weights, salivation, ruffled fur, dyspnea, 

muscle spasms, and sedation) and 

peripheral nerve damage in males

44900601 Subchronic Gavage (corn 

oil)

0, 2, 8, 32 rat 2 clinical signs of toxicology, excessive 

grooming and bulging eyes (females)

Metofluthrin (109709) 46406728 Acute Gavage (Corn 

Oil, 5 ml/kg)

0, 20, 50, 100 rat 100 mortality, adverse signs (twitching, 

tremors, and convulsions), FOB effects 

and increased motor activity
Appendix 1. Toxicity Data for Screening Level Cumulative Risk Assessment

A1-9

Pyrethroid (PC Code) MRID Study Route of 

Administration Doses (mg/kg) Species

LOAEL*

(mg/kg) Endpoints

46406729 Subchronic Dietary Admix 0,18.3, 59.8, 

178.8

rat 178 mortality (females only), clinical signs 

(soft/liquid feces and scant feces in the 

males and tremors and twitches in the 

females), decreased body weight, body 

weight gain, and absolute and relative 

food consumption

Permethrin (109701 43046301 Acute gavage (Corn 

Oil, 0/300 

mg/kg-30

ml/kg, 10 

mg/kg-1 ml/kg, 

150 mg/kg-15 

ml/kg)

0, 10, 150, 300 rat 300 death (1 female), tremors, staggered 

gait, gait impairment, splayed 

hindlimbs, decreased forelimb grip 

strength

45657401 Acute gavage (corn 

oil, 1 ml/kg)

0, 25, 75, 150 rat 75 several neurotoxicity parameters 

affected

40766807 Subchronic dietary admix 0, 100, 200, 

400

rat 200 tremors and irritability

42933701 Subchronic dietary admix 0, 15.5, 91.5, 

150.3

rat 91.5 tremors, staggered and/or impaired 

gait, splayed hindlimbs, increased

landing foot splay, abnormal posture 

and decreased grip strength, decreased 

body weight

00129600 Chronic capsule (corn 

oil)

0, 5, 100, 1000 dog 1000 tremors, uncoordinated gait, 

convulsions, excessive salivation, 

vomiting

00110647 Subchronic capsule 0, 5, 50, 500 dog 500 clinical signs of toxicity (tremors, 

transient narcosis with nystagmus)

Pyrethrins (69001) 42925801 Acute gavage (corn 

oil, 

0, 40, 125, 400 

pyrethrum 

extract 

containing 

57.5% 

pyrethrins

rat 63 tremors in females
Appendix 1. Toxicity Data for Screening Level Cumulative Risk Assessment

A1-10

Pyrethroid (PC Code) MRID Study Route of 

Administration Doses (mg/kg) Species

LOAEL*

(mg/kg) Endpoints

Resmethrin, 

bioresmethrin, transbioresmethrin (097801)

43838101 Subchronic dietary admix 0, 35, 88, 180, 

366

rat 88 increased absolute liver weight, 

increased BUN, moderate thyroid 

follicular cell vacuolization in females, 

moderate periportal to diffuse 

hepatocyte hypertrophy and 

vacuolization

Tefluthrin (128912) 40141304 Subchronic dietary admix 0, 2.5, 7.5, 

17.5B

(0, 50, 150, 

350 ppm)

rat 7.5 changes in hemoglobin, cholesterol and 

liver weight

Tetramethrin (069003) 42601501/

43495501

Acute gavage (0.5% 

carboxymethylc

ellulose, 20 

ml/kg)

0, 500, 1000, 

2000

rat >2000 LOAEL – Not Observed

A

Acute studies are single dose studies; therefore exposure is mg/kg B

Doses in study listed as parts per million (PPM); mg/kg/day values are approximations by author