BIOPESTICIDES REGISTRATION ACTION DOCUMENT

Tea Tree Oil 

 PC Code : 028853 

U.S. Environmental Protection Agency 

 Office of Pesticide Programs 

Biopesticides and Pollution Prevention Division 

August 11, 2014 
Tea Tree Oil 

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 TABLE OF CONTENTS 

I. EXECUTIVE SUMMARY: ................................................................................................ 5

II. ACTIVE INGREDIENT OVERVIEW ............................................................................. 6

III. REGULATORY BACKGROUND...................................................................................... 6

A. Classification ........................................................................................................................ 6

B. Food Clearances/Tolerances ............................................................................................... 6

IV. RISK ASSESSMENT ......................................................................................................... 7

A. Active Ingredient Characterization.................................................................................... 7

B. Human Health Assessment.................................................................................................. 8

1. Toxicology ...................................................................................................................................................... 8

2. Dose Response Assessment ......................................................................................................................... 13

3. Food Quality Protection Act (FQPA) Considerations .............................................................................. 13

4. Occupational, Residential, School and Day Care Exposure and Risk Characterization ...................... 18

5. Aggregate Exposure from Multiple Routes Including Dermal, Oral, and Inhalation ........................... 20

6. Cumulative Effects ...................................................................................................................................... 20

7. Risk Characterization ................................................................................................................................. 21

C. Environmental Assessment ............................................................................................... 21

1. Ecological Hazards ...................................................................................................................................... 21

2. Environmental Fate and Ground Water Data .......................................................................................... 21

3. Ecological Exposure and Risk Characterization ...................................................................................... 22

4. Endangered Species Assessment ................................................................................................................ 22

D. Product Performance Data .............................................................................................. 22

V. RISK MANAGEMENT DECISION ................................................................................ 23

A. Determination of Eligibility for Registration .................................................................. 23

B. Regulatory Decision ........................................................................................................... 23

C. Environmental Justice ....................................................................................................... 23

VI. ACTIONS REQUIRED BY REGISTRANTS................................................................. 23

A. Reporting of Adverse Effects ............................................................................................ 24

B. Reporting of Hypersensitivity Incidents .......................................................................... 24
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VII. APPENDIX A. DATA REQUIREMENTS (40 CFR PART 158-SUBPART U) .......... 24

VIII. APPENDIX B. .................................................................................................................... 29

IX. APPENDIX C. ................................................................................................................... 29

X. GLOSSARY OF ACRONYMS AND ABBREVIATIONS ............................................. 30

 
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Biopesticides Registration Action Document 

BIOPESTICIDES REGISTRATION ACTION DOCUMENT (BRAD) TEAM 

Branch Chief 

Linda A. Hollis, M.S. 

Product Chemistry/Human Health Effects/Nontarget Organisms 

Angela L. Gonzales, Biologist 

Regulatory Action Leader

Colin G. Walsh, M.S., Biologist 
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I. EXECUTIVE SUMMARY: 

Tea tree oil is a new biochemical pesticide active ingredient intended for non-food use treatment 

as a fungicide/bactericide on the following food commodities: leafy vegetables (group 4), 

fruiting vegetables (group 8), cucurbit vegetables (group 9), berries (group 13), tree nuts (group 

14), cereal grains (group 15), avocado, banana, mango, papaya, passion fruit, plantain, and 

peanuts. The active ingredient is extracted from the leaves and terminal branches of the tea tree 

(Melaleuca alternifolia), which is a member of the plant family Myrtaceae and is indigenous to 

Australia, New Zealand, and Southeast Asia. Tea tree oil is composed of approximately 100 

different compounds which consist of terpene hydrocarbons, primarily monoterpenes, 

sesquiterpenes, and their associated alcohols. The active ingredient has antifungal properties and 

is effective against a broad spectrum of plant-pathogenic fungi. Tea tree oil has been shown to 

affect cell respiration and alter cell membrane structure in yeast. Based on this information, the 

Agency considers the mode of action to be nontoxic. 

The Biopesticides and Pollution Prevention Division (BPPD) has reviewed all of the data and 

other information submitted in support of the registration of tea tree oil as a fungicide/bactericide 

under Section 3(c)(5) of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), and 

has determined that the current data requirements (40 CFR part 158.2010 through 158.2070) for 

registration of a biochemical pesticide have been satisfied. Given that tea tree oil is of low 

toxicity and presents little, if any, risks to humans, including infants and children, and the 

environment, the U.S. Environmental Protection Agency (EPA or the Agency) has concluded 

that it is in the best interest of the public to issue registrations for the manufacturing-use product 

(MP), Tea Tree Oil Technical (EPA File Symbol No. 86182-E), and the end-use product (EP), 

Timorex Gold (EPA File Symbol No. 86182-R), which contain this new active ingredient, tea 

tree oil. The basis for this decision is described in more detail in section IV of this Biopesticide 

Registration Action Document (BRAD). 

On October 1, 2009, EPA announced a policy to provide a more meaningful opportunity for the 

public to participate on major registration decisions before they occur. According to this policy, 

EPA provides a public comment period prior to making a registration decision for the following 

types of applications: new active ingredients, first food use, first outdoor use, first residential 

use; and any registration decisions for which the Agency believes there may be substantial public 

interest. 

Consistent with the policy of making registration actions more transparent, tea tree oil is subject 

to a 15-day comment period as a “new active ingredient.” EPA has established a comment period 

of 15 days on the basis of tea tree oil’s low toxicity, the determination that tea tree oil presents 

low risk of any adverse effects to human health and the environment, and need for this active 

ingredient. The notice for this comment period includes the draft BRAD and draft product labels 

for the MP, Tea Tree Oil Technical, and EP, Timorex Gold, which contain this new active 

ingredient, tea tree oil. The docket identification (ID) number is EPA-HQ-OPP-2009-0440. The 

Agency believes that based on the risk assessment and information submitted in support of the 

registration of the MP and EP containing tea tree oil, it is in the best interests of the public to 

issue the registration for Tea Tree Oil Technical and Timorex Gold. The basis for this decision 

can be found in the risk assessment for tea tree oil, which is characterized in this BRAD. 
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For definitions of scientific terms, please refer to http://www.epa.gov/pesticides/glossary/. 

II. ACTIVE INGREDIENT OVERVIEW 

Common Name: Tea Tree Oil

 Chemical Names: Tea Tree Oil; Oils, tea-tree

 

Trade & Other Names: Tea Tree Oil Technical 

 CAS Registry Number: 68647-73-4 

OPP Chemical Code: 028853 

Type of Pesticide: Fungicide/Bactericide 

III. REGULATORY BACKGROUND 

On April 10, 2009, EPA received an application filed by Technology Sciences Group, Inc. 

(TSG), 1150 18th Street, NW, Suite 1000, Washington, DC 20036, on behalf of Biomor Israel, 

Ltd. (Biomor), P.O. Box 81, Qatzrin, 12900 Israel, to register the products, Timorex Gold (EPA 

File Symbol No. 86182-R) and Tea Tree Oil Technical (EPA File Symbol No. 86182-E), 

containing the new biochemical active ingredient, tea tree oil. A notice of receipt (NOR) of this 

application, allowing for a 30-day comment period, was published in the Federal Register on 

July 22, 2009 (74 FR 36215). No comments were received following this publication. 

A. Classification

On October 28, 2004, EPA’s Biochemical Classification Committee determined that tea tree oil 

is a biochemical pesticide. The biochemical classification committee indicated that tea tree oil is 

a fungicide/bactericide. The active ingredient has been shown to disrupt membranes of 

fungal/bacterial species. Tea tree oil is the essential oil of the Melaleuca tree (tea tree) and is rich 

in terpene alcohols (such as terpinen-4-ol and eucalpyptol). The oil is manufactured to contain at 

least 30% terpinen-4-ol (germicidal) and no more than 15% eucalpyptol (anti-fungal). The 

terpinen-4-ol is generally accepted to be the active component of tea tree oil. There is a long 

history of use of tea tree oil as an antiseptic and antifungal agent and it is formulated into creams, 

soaps, mouthwashes, toothpaste, and other cosmetic products. 

B. Food Clearances/Tolerances 

The consultant, TSG on behalf of Biomor, filed a petition (PP 9F7558) proposing to establish an 

exemption from the requirement of a tolerance for residues of tea tree oil in or on all food 

commodities. A notice of filing (NOF), allowing for a 30-day comment period, was published in 
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the Federal Register on July 22, 2009 (74 FR 36200). No comments were received following this 

publication. 

EPA determined during the review of the petition that the data and information submitted was 

insufficient to support an exemption from the requirement of a tolerance for residues of tea tree 

oil in or on all food commodities. However, as noted in the Risk Assessment section of this 

BRAD (Section IV), EPA has made a non-food use determination, with limitations, for the 

following food commodities: leafy vegetables (group 4), fruiting vegetables (group 8), cucurbit 

vegetables (group 9), berries (group 13), tree nuts (group 14), cereal grains (group 15), avocado, 

banana, mango, papaya, passion fruit, plantain, and peanuts. The limitations for the non-food use 

determination are a pre-harvest interval (PHI) of 48 hours and a maximum application rate of 

1.54 lbs a.i./acre (EPA, 2014b). 

IV. RISK ASSESSMENT 

A. Active Ingredient Characterization 

Tea tree oil is a new biochemical pesticide active ingredient intended for use to prevent and 

control diseases such as powdery mildew, Botrytis, and black sigatoka in horticultural and 

agricultural crops. The active ingredient has antifungal properties and is effective against a broad 

spectrum of plant-pathogenic fungi, but the mode of action is not clearly understood. It has been 

shown to affect cell respiration and alter cell membrane structure in yeast. Based on this 

information, the Agency considers the mode of action to be nontoxic. 

The active ingredient is extracted from the leaves and terminal branches of the tea tree 

(Melaleuca alternifolia) which is a member of the plant family Myrtaceae and is indigenous to 

Australia, New Zealand, and Southeast Asia. Tea tree oil is composed of approximately 100 

different compounds which consist of terpene hydrocarbons: primarily monoterpenes, 

sesquiterpenes, and their associated alcohols. These biogenic chemicals are aromatic 

hydrocarbons which are found in the essential oils of a multitude of plants and are characterized 

by their high volatility and low aqueous solubility (EPA, 2010). The composition of tea tree oil 

used in commerce is regulated by an international standard (ISO 4730, International 

Organization for Standardisation), which sets maximum and minimum limits for 14 of its 

components. Of the several varieties or chemotypes of tea tree oil, only the terpinen-4-ol 

chemotype, which contains 30-48% terpinen-4-ol, will be used as the TGAI in the proposed MP, 

Tea Tree Oil Technical (EPA File Symbol No. 86182-E). ISO 4730 defines the main ingredients 

as α-terpinine (5-13%); 1,8-cineole (traces to 15%); γ-terpinine (10-28%); p-cymene (0.5-12%); 

and terpinen-4-ol (30-48%). The specifications for all 14 ingredients are listed in Table 1 below. 

TABLE 1. Specifications of Tea Tree Oil Components per ISO Standard 47301

Name CAS No. Minimum % Maximum % 

Terpinen-4-ol 562-74-3 30 48 

γ-Terpinine 99-85-4 10 28 

α-Terpinine 99-86-5 5 13 

α-Terpineol 98-55-5 1.5 8 

α-Terpinolene 586-62-9 1.5 5 
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α-Pinene 80-56-8 1 6 

p-Cymene 99-87-6 0.5 8 

1,8-Cineole 470-82-6 Trace 15 

Limonene 138-86-3 0.5 1.5 

Aromadendrene 489-39-4 0.5 3 

δ-Cadinene 483-76-1 Trace 3 

Sabinene 3387-41-5 Trace 3.5 

Globulol 489-41-8 Trace 1 

Viridiflorol 552-02-3 Trace 1 

Ledene Trace 3 1

from MRID 47730409 

Humans are already naturally exposed to the major constituents of tea tree oil (terpinen-4-ol, γterpinene, 1,8-cineole, and α-terpinene) in the diet as they are found in herbs, spices, fruits, and 

some vegetables (EPA, 2014b). Humans are also exposed to the major constituents of tea tree oil 

as food additives in the diet, as they have been approved as substances that may directly be 

added to food by the U.S. Food and Drug Administration (FDA) under 21 CFR § 172.515(b). 

Tea tree oil is comprised of primarily terpenes and their associated alcohols which are found in 

the environment as they are emitted by and present in a variety of plant species and water 

sources. Additionally, tea tree oil has a long history of use as a remedy for acne, eczema, skin 

infections, cold sores, blisters, and warts; and is used in cosmetic and personal care products 

such as shampoo, toothpaste, mouthwash, deodorants, lotions, and bath oils, as well as in animal 

care products (EPA, 2010). 

Descriptions of the product formulation and production process, formation of impurities, and 

physical and chemical characteristics of tea tree oil were examined by BPPD and found to be 

acceptable in meeting current guideline standards. 

All product chemistry data requirements for registration of tea tree oil have been satisfied. 

For more information regarding product chemistry data requirements, refer to Tables 4 and 5 in 

Appendix A. 

B. Human Health Assessment

1. Toxicology 

For acute toxicity data requirements, toxicity categories are assigned based on the hazard(s) 

identified from studies and/or information on file with the Agency. The active ingredient is 

classified into Toxicity Category I, II, III, or IV where Toxicity Category I indicates the highest 

toxicity and Toxicity Category IV indicates the lowest toxicity. 

Adequate mammalian toxicology data/information is available to support registration of tea tree 

oil. All toxicology data requirements for tea tree oil have been satisfied. 
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a. Acute Toxicity 

Acute toxicity testing is required to: 1) determine systemic toxicity from acute exposure via the 

dermal, inhalation, and oral routes; 2) determine irritant effects from exposure to the eyes; and 3) 

determine the potential for skin sensitization (allergic contact dermatitis). 

A Tier I primary dermal irritation study in rabbits submitted and reviewed showed that tea tree 

oil is corrosive to the skin at undiluted concentrations (toxicity category I). Based on the results 

in the primary dermal irritation study, the primary eye irritation and dermal sensitization data 

requirements were waived; therefore, tea tree oil is classified as corrosive to the eye (toxicity 

category I). Tea tree oil is a toxicity category III (slightly toxic) compound via the acute oral and 

dermal toxicity routes of exposure based on a median lethal dose (LD50) of 1,752 mg/kg body 

weight in rats and a LD50 of greater than 2,000 mg/kg in rabbits, respectively. Tea tree oil is a 

toxicity category IV (not toxic) compound for acute inhalation toxicity based on a medial lethal 

concentration (LC50) of 3.64 mg/L. 

For more information regarding acute toxicity data requirements, refer to Table 6 in Appendix A. 

 b. Subchronic Toxicity 

Subchronic data are required to determine a no-observed-effect-level (NOEL) and any toxic 

effects associated with repeated or continuous exposure to a test substance for a period of 90 

days via the oral, dermal, and inhalation routes of exposure. 

A 90-day oral toxicity study (OCSPP 870.3100) was conducted on tea tree oil and submitted in 

MRID 48598702. Adequate supportive information regarding homogeneity testing of the test 

substance was submitted in MRID 48878202. Tea tree oil was administered to Wistar rats by 

gavage at dosages of 0 (peanut oil), 30, 60 or 120 mg/kg/day. An additional 20 rats were 

included in the high dose group, and an additional 10 rats were included in the control group. To 

determine the reversibility of any effects observed, 10 rats from the high dose group and 5 rats 

from the control group were sacrificed 14 days and 28 days after completion of the 90-day 

dosing period. No mortality was observed in male rats. Two moribund females in the high dose 

group were sacrificed during the treatment period. At all dose levels salivation was observed 

which persisted for about 30 minutes after dosing. Salivation incidences were dose-related. No 

treatment-related effects on body weight and body weight gain were observed. Toxicologically 

relevant hematological, clinical chemistry, or urinalysis findings were not noted at any dose 

level. In the high dose group, some motor activity measurements were statistically (p≤0.05) 

affected in both sexes; however, the toxicological significance of these observations is unclear as 

there was no correlation with abnormal functional observations. Statistically significant increases 

in liver to body weight ratios at the mid- and high-dose levels (+11% and +9%, respectively) 

were noted in females, and a significant increase in ovary to body weight ratio was noted in the 

28-day high dose recovery group (+31%). There was no microscopic correlation for the organ 

weight findings in females. Flaccid testes, some with a small appearance, were observed in highdose males (4/10 at the end of treatment; 2/10 after the 14-day recovery period; 8/10 after the 28-

day recovery period). Absolute organ weight and organ-to-body-weight ratios were significantly 

reduced in the testes and epididymides of males in the high-dose 28-day recovery group. These 
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findings were microscopically associated with degenerative changes in the seminiferous tubules 

(loss of germ cells, formation of multinucleated germ cells, presence of cell debris in tubular 

lumen, atrophic appearance, and sertoli cell vacuolation). The testicular effects occurred at the 

same or higher rate of incidence with an overall greater degree of severity in the high dose 

animals in the 14-day and 28-day recovery groups. Sperm granulomas and cellular debris in the 

lumen (inflammation involving epididymal lumen and interstitium with the presence of large 

zones of spermatozoa surrounded by a zone of macrophages, giant cells and fibroblasts) were 

observed in the epididymides of high dose males at the end of the 90-day treatment period. The 

incidence of sperm granulomas peaked in the 14-day recovery group, but the incidence and 

severity of cellular debris in the epididymal lumen increased in the 14- and 28-day recovery 

groups. Minimal cell debris was observed in the lumen of the epididymides in 1/10 male rats 

dosed at 60 mg/kg/day. No treatment-related histological changes were observed in males dosed 

at 30 mg/kg/day. Statistically significant treatment-related effects on sperm motility, sperm 

morphology, and epididymal sperm counts were observed at the high dose level at the end of the 

treatment period and in the 14- and 28-day recovery groups. Sperm counts were significantly 

lower relative to controls in the mid-dose group, and there was a significant decrease in sperm 

motility and an insignificant increase in abnormal sperm at this dose level. Based on these data, 

the lowest-observed-adverse-effect level (LOAEL) of tea tree oil in rats was 60 mg/kg/day based 

on testicular toxicity in males and increased liver to body weight ratios in females. The noobserved-adverse-effect level (NOAEL) is 30 mg/kg/day for males and females (EPA, 2013). 

A 90-day dermal toxicity study was not submitted and is not required. Exposure via the dermal 

route is not anticipated due to the following: 1) prolonged dermal exposure is not expected 

because the product is not purposely applied to the skin and handlers/applicators are required to 

wear appropriate personal protective equipment (PPE); 2) a 4-hour restricted-entry interval (REI) 

requirement has been included on the proposed EP label which will further mitigate exposure; 

and 3) tea tree oil has a long history of use in a variety of dermally-applied products, including 

shampoo, deodorants, lotions, and antifungal treatments. In a non-guideline 30-day dermal 

irritation study on rabbits (MRID 47730404), undiluted tea tree oil caused severe irritation to the 

skin on the first day of the study. For the remainder of the study, a 25% solution in paraffin oil 

was applied to the skin which did not result in visible irritation; however, non-specific 

microscopic dermatitis consistent with irritation was observed (EPA, 2013). 

A 90-day inhalation toxicity study was not submitted for tea tree oil. In lieu of a study, the 

applicant cited the data from the 90-day oral toxicity study (MRID 48598702). Due to the use 

pattern of the active ingredient as a spray and the volatility of the constituents of tea tree oil, 

exposure to handlers/applicators is possible. There are no PPE requirements regarding mitigation 

of inhalation exposure on the proposed EP label. A route to route extrapolation using the default 

assumption that 100% of the tea tree oil is absorbed into the body has been employed. The 

Agency is confident that this approach is protective of potential repeat exposure inhalation 

toxicity for the following reasons: 1) tea tree oil is classified into Toxicity Category IV for acute 

inhalation toxicity and Toxicity Category III for acute oral toxicity; and 2) humans are already 

exposed to the constituents of tea tree oil as the oil is used in a variety of dermally-applied 

cosmetic and pharmaceutical products. Moreover, five of the main components of tea tree oil 

(terpinen-4-ol, γ-terpinine, α-terpinine, p-cymene, and 1,8-cineole) are all approved for use by 

the FDA as direct food additives under 21 CFR 172.515. Further, in an occupational risk 
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assessment conducted for applicators and handlers (who may be exposed via inhalation to tea 

tree oil), margins of exposure (MOEs) were derived and were significantly higher than the 

Agency’s level of concern (LOC) of 100 (MOEs ranged from 4,900 to 150,000). Because the 

MOEs were significantly higher than the LOC, the Agency believes that an adequate margin of 

safety has been achieved to account for any potential difference in toxicity from oral versus 

inhalation exposure (EPA, 2013). 

For more information regarding the subchronic toxicity data requirements, refer to Table 7 in 

Appendix A. 

 c. Developmental Toxicity and Mutagenicity 

A developmental toxicity study conducted on tea tree oil was submitted in MRID 49166401. In 

the study, Wistar rats were administered doses of tea tree oil by gavage at 0, 30, 60, or 120 

mg/kg/day from day 5 to day 19 of gestation. Each treatment group consisted of 24 female rats; 

the control group which received peanut oil, the test substance vehicle, also consisted of 24 

female rats. Initially, rats were dosed at 75, 150, and 300 mg/kg/day; however, there was a 

mortality on day two of treatment in the high dose group and treatment related clinical signs in 

the mid- and high-dose groups. Consequently, doses were reduced to 30, 60 and 120 mg/kg/day. 

At the start of treatment, animals were approximately 13-15 weeks old, within a weight range of 

approximate 224g ± 15g and healthy in appearance. Animal acclimatization, housing, diet, and 

water supply were reported adequately. Test substance characterization and preparation was also 

reported adequately. Animals were dosed once a day at approximately the same time each day. 

Physical examinations occurred on day 0 of gestation and at weekly intervals during the 

gestation period. Clinical observations occurred at least twice a day on treatment days (pre- and 

post-dosing) and once a day on other days. Body weights were measured on days 0, 3 and 5, 8, 

11, 14, 17, and 20 after mating and food consumption was measured throughout the study. 

Animals were sacrificed on day 20 after mating under isoflurane anesthesia. Gross necropsy was 

performed on all rats, which consisted of external observation and examination of thoracic and 

abdomen viscera and examination of uterine contents. Gravid uterine weights, the number of 

corpora lutea in each ovary, the number of implantation sites, the number of early and late 

resorptions sites, the number of live and dead fetuses, individual fetal body weights, fetal sex, 

and the fetal sex ratio were recorded. Fetuses were also examined for external abnormalities, 

visceral organ abnormalities and skeletal development and abnormalities. Statistical analyses of 

the data were provided in the study. Significant reductions in maternal body weight gain and 

food intake were observed during the treatment period in the mid- and high-dose groups and 

throughout gestation in the high dose group. These observations were considered treatment 

related. No gross pathological findings were observed in the dams in any group. At all dose 

levels, mean gravid uterine weights, the number of corpora lutea, the number of implantations, 

and pre and post-implantation losses were all statistically comparable to the control group. 

Significant resorption was observed in dams in the high dose group when compared to the 

control group. At all dose levels, the total number of fetuses, mean litter size, number of live 

fetuses, and the sex ration were all statistically comparable to the control group. Mean fetal body 

weights of males, females, and total fetuses were significantly reduced at the mid and high dose 

level; however, the weights of the fetuses in the mid dose group were comparable to historical 

control data. Any fetal anomalies and abnormalities that were observed were routinely observed 
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in rat fetuses, were comparable to the control group or were comparable to historical control 

data; none were considered treatment related. Based on the results of the study, the maternal 

NOAEL is 30 mg/kg/day and the LOAEL is 60 mg/kg/day based on reduced body weight gain 

and food consumption. The developmental NOAEL is 60 mg/kg/day and the LOAEL is 120 

mg/kg/day based on reduced fetal body weight (EPA, 2014a). 

In a study published in the New England Journal of Medicine (Henley, 2007), study authors 

reported that repeated topical exposure to lavender and tea tree oils may cause prepubertal 

gynecomastia in boys. Three prepubertal boys who were otherwise healthy and had normal 

serum concentrations of endogenous steroids exhibited gynecomastia that coincided with the 

topical application of products that contained lavender and tea tree oils. The effect resolved in 

each boy shortly after the use of the products was discontinued. The authors also reported that 

studies in human cell lines indicated that lavender and tea tree oils had estrogenic and 

antiandrogenic activities. Although the study suggests that exposure to topical applications of 

products containing lavender and tea tree oils may result in gynecomastia in boys, the Agency 

has concluded that the uses of tea tree oil as a pesticide will not result in unreasonable adverse 

effects to this population subgroup. This conclusion is based upon the following: 1) tea tree oil 

will not be applied topically to the skin. The active ingredient will be applied to crops as an 

agricultural use; thus, exposure is mainly anticipated to be via the oral route, 2) dietary exposure 

to tea tree oil as a pesticide is anticipated to be minimal as it degrades rapidly in the 

environment, 3) dermal exposure is not anticipated to result in risk as occupational exposure 

assessments (see subchronic toxicity section above) indicate MOEs that do not exceed the 

Agency’s level of concern, and 4) humans are already exposed to the constituents of tea tree oil 

as they are found naturally in the diet, are used as food additives, and are found in a variety of 

cosmetic and pharmaceutical products. 

A Tier I mutagenicity study [in vitro reverse gene mutation assay (Ames) using Salmonella 

typhimurium strains TA98, TA100, and TA102 (MRID 47730404)] showed that tea tree oil did 

not increase the number of revertants at doses of <50 μg in the presence or absence of S9 

metabolic activation. A Tier II mutagenicity study [in vivo mammalian erythrocyte micronucleus 

assay (MRID 47730407)] showed that tea tree oil did not produce a statistically significant 

increase in the frequency of micronucleated polychromatic erythrocytes in bone marrow of mice 

given oral doses of 1000-1750 mg/kg body weight. Therefore, under the conditions of both 

assays, tea tree oil is considered to be non-mutagenic. 

For more information regarding prenatal developmental and mutagenicity data requirements, 

refer to Table 7 in Appendix A. 

d. Tier II/Tier III 

Tiers II and III data were not required due to the nature of the active ingredient and its intended 

uses in potential new EP products (fungicides/bactericides). 

e. Effects on the Endocrine System 

As required under Federal Food, Drug, and Cosmetic Act (FFDCA) section 408(p), EPA has 
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developed the Endocrine Disruptor Screening Program (EDSP) to determine whether certain 

substances (including pesticide active and other ingredients) may have an effect in humans or 

wildlife similar to an effect produced by a “naturally occurring estrogen, or other such endocrine 

effects as the Administrator may designate.” The EDSP employs a two-tiered approach to 

making the statutorily required determinations. Tier 1 consists of a battery of 11 screening assays 

to identify the potential of a chemical substance to interact with the estrogen, androgen, or 

thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and are found 

to have the potential to interact with E, A, or T hormonal systems will proceed to the next stage 

of the EDSP where EPA will determine which, if any, of the Tier 2 tests are necessary based on 

the available data. Tier 2 testing is designed to identify any adverse endocrine related effects 

caused by the substance, and establish a dose-response relationship between the dose and the E, 

A, or T effect.

Between October 2009 and February 2010, EPA issued test orders/data call-ins for the first 

group of 67 chemicals, which contains 58 pesticide active ingredients and nine inert ingredients. 

This list of chemicals was selected based on the potential for human exposure through pathways 

such as food and water, residential activity, and certain post-application agricultural scenarios. 

This list should not be construed as a list of known or likely endocrine disruptors.

Tea tree oil is not among the group of 58 pesticide active ingredients on the initial list to be 

screened under the EDSP. Under FFDCA section 408(p) the Agency must screen all pesticide 

chemicals. Accordingly, EPA anticipates issuing future EDSP test orders/data call-ins for all 

pesticide active ingredients. 

For further information on the status of the EDSP, the policies and procedures, the list of 67 

chemicals, the test guidelines and the Tier 1 screening battery, please visit our website: 

http://www.epa.gov/endo/.

2. Dose Response Assessment

The NOAEL of 30 mg/kg bw/day has been selected as the point of departure (POD) for the 

hazard and risk assessment. The NOAEL is based on toxic endpoints observed in the 90-day oral 

toxicity study. The POD is protective of developmental toxicity because the NOAEL in the 90-

day oral toxicity study is lower than the developmental (fetal) toxicity NOAEL of 60 mg/kg 

bw/day. 

3. Food Quality Protection Act (FQPA) Considerations 

 a. Dietary Exposure and Risk Characterization

EPA has made a non-food use determination, with limitations, for the following food 

commodities: leafy vegetables (group 4), fruiting vegetables (group 8), cucurbit vegetables 

(group 9), berries (group 13), tree nuts (group 14), cereal grains (group 15), avocado, banana, 

mango, papaya, passion fruit, plantain, and peanuts. The limitations for the non-food use 

determination are a PHI of 48 hours and a maximum application rate of 1.54 lbs a.i./acre (EPA, 
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2014b). The Agency’s reasoning for the non-food use determination, with limitations, for tea tree 

oil is provided below. 

As stated earlier in the document, the major components of tea tree oil are moderately to highly 

volatile substances. A substance with a high vapor pressure at normal temperatures is often 

referred to as volatile. The vapor pressure is an indication of a substance's evaporation rate and 

relates to the tendency of particles to escape from the substance. Up to 90% of tea tree oil has 

been shown to volatilize within 24 hours after application (Chadwick, 2008; Gatenio, 2007). 

Based on these studies, substantial volatilization is expected within the first 24 hours of 

application from plant, soil, and water surfaces. Tea tree oil constituents are quickly broken 

down in air through atmospheric reactions (PMRA, 2014; EFSA, 2012). Further, residue data 

reviewed by EPA in support of this non-food use determination indicate the absence of 

quantifiable residues on tomatoes, peppers, and bananas immediately after application when tea 

tree oil was applied at a proposed application rate of 1.54 pounds of active ingredient per acre. 

These data demonstrate that tea tree oil, when applied at that application rate, volatilizes even 

faster than what is reported in the Chadwick & Gatenio reports referenced above in this 

paragraph, and volatilizes completely. Volatilization from plant surfaces and soil can be a major 

dissipation pathway for pesticides applied to crops. Generally, pesticides volatilize from plant 

surfaces faster and to a greater extent than from soil (Bedos, 2002). Pesticide volatilization from 

plant surfaces often occurs rapidly after application (Bedos, 2002). For example, 30 to 50% of 

lindane (vapor pressure estimated at 5 x 10-4 mmHg) was reported to volatilize from plant 

surfaces within one hour application regardless of the crop species, canopy structure or plant age 

(Bedos et al., 2002). More than 90% of the lindane application volatilized from the plant surfaces 

over a period of 3 days. The data suggest that over longer periods after application, leaf 

characteristics do not interfere with volatilization (Bedos, 2002). Most of the pesticides evaluated 

by Bedos for volatilization after application have low vapor pressures, such as diazinon, with a 

vapor pressure of 5.43 x 10-5 mmHg, or dieldrin with a vapor pressure of 1.77x 10-5 mmHg (as 

estimated by EpiSuiteTM). These data suggest that tea tree oil, which has a much higher vapor 

pressure than the example pesticides presented by Bedos (2002), would readily volatilize from 

plant surfaces soon after application, regardless of the surface area of the plant. Table 2 provides 

information on the vapor pressures of the constituents of tea tree oil all of which were measured 

at or near room temperature. As indicated in the table, the vapor pressure of tea tree oil is 

significantly higher than (by a magnitude of ~ 10,000) diazinon, a pesticide that has a low vapor 

pressure and therefore is not considered to be a volatile substance. 

Table 2. Vapor Pressures of Tea Tree Oil Constituents 

Component Temperature (°C) Vapor Pressure (mmHg) 

Terpinen-4-ol 20 0.40 

ɤ-terpinene 20 0.70 

ɤ-terpinene 23.5 0.77 

α-terpinene 20 0.80 

p-cymene 25 1.50 

1,8-cineole 25 1.90 

Residue studies were submitted in which products containing varying amounts of tea tree oil 

(one to seven times the proposed application rate) were applied to tomatoes, peppers, and 

bananas. Analyses for residues of the three major components in the oil (terpinen-4-ol, γ-
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terpinene, and 1,8-cineole) were performed in the studies. No detectable residues (below the 

limit of quantification [LOQ] which was 0.05 ppm for the residue studies) were found in any of 

the commodities at the proposed application rate. The LOQ is the lowest amount of a substance 

that can be distinguished from the absence of that substance for any particular analytical method. 

Residue studies were submitted in which a product was tested at approximately seven times (7X) 

the proposed application rate on tomatoes and peppers. No detectable residues were found in 

tomatoes. Detectable residues of terpinen-4-ol only were found for up to 48-hours on peppers at 

the 7X application rate. No detectable residues were found at 48-hours post-application. 

Acceptable residue data have not been submitted for any other crop. The available data indicate 

that residues of tea tree oil are not likely to be present on edible commodities when tea tree oil is 

applied at the proposed application rate with a PHI of 48 hours. As stated above, the major 

constituents of tea tree oil are found naturally in most of the crops and crop groups listed in this 

document. Tea tree oil is primarily comprised of terpenes and their associated alcohols, all of 

which are found in a multitude of plants, as they are ubiquitous in the environment. Therefore, 

based on the rapid volatilization from the plant surfaces, it is likely that even if there are any tea 

tree oil constituent residues, the residues of these substances will not be distinguishable from 

background levels when tea tree oil is applied at the proposed application rate and at the PHI of 

48 hours. 

Rationale behind the non-food use determination for each crop group 

Fruiting vegetables (group 8): tomatoes and peppers are representative commodities in this crop 

group. Residue studies on these crops indicate that 1) residues are not likely to be present on 

treated commodities in this crop group when tea tree oil is applied at an application rate of 1.54 

lbs a.i./acre and 2) residues are not likely to be present on treated commodities after 48 hours 

when tea tree oil is applied at an application rate approximately seven times the proposed rate. 

The limitation in the non-food use determination for tea tree oil would be that the active 

ingredient cannot be applied at more than 1.54 lbs a.i./acre; therefore, residues are not likely to 

be present on these commodities when consumed. 

Leafy vegetables (group 4): even though residue data have not been submitted for leafy 

vegetables, the residue data on fruiting vegetables (tomatoes and peppers) can be bridged to this 

crop group and a non-food use determination can be made based on the following: 1) as stated 

above, the data from Bedos (2002) suggest that leaf characteristics do not interfere with 

volatilization; thus, the difference in surface texture between fruiting and leafy vegetables is not 

likely to affect residue profiles; 2) a 48-hour PHI would give ample time for volatilization of the 

constituents of tea tree oil from plant surfaces. Further, the PHI of 48 hours is further supported 

because residues of terpinen-4-ol were below the LOQ by 48 hours in the residue study where 

tea tree oil was applied at the 7X application rate; and 3) the limitation in the non-food use 

determination for tea tree oil would be that the active ingredient cannot be applied at more than 

1.54 lbs a.i./acre, the level at which no detectable residues of tea tree oil were found. This 

information indicates that residues of tea tree oil are not likely to be present when these 

commodities are consumed. 

Cucurbit vegetables (group 9): even though residue data have not been submitted for cucurbits, 

the residue data on fruiting vegetables (tomatoes and peppers) can be bridged to this crop group 
Tea Tree Oil 

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Biopesticides Registration Action Document 

and a non-food use determination can be made based on the following: 1) residue profiles are 

anticipated to be similar between cucurbits and fruiting vegetables because they have similar 

surfaces (smooth, non-textured); 2) a 48-hour PHI would give ample time for volatilization of 

the constituents of tea tree oil from plant surfaces. Further, the PHI of 48 hours is further 

supported because residues of terpinen-4-ol were below the LOQ by 48 hours in the residue 

study where tea tree oil was applied at the 7X application rate and 3) the limitation in the nonfood use determination for tea tree oil would be that the active ingredient cannot be applied at 

more than 1.54 lbs a.i./acre, the level at which no detectable residues of tea tree oil were found. 

This information indicates that residues of tea tree oil are not likely to be present when these 

commodities are consumed. 

Berries (group 13): even though residue data have not been submitted for berries, the residue 

data on fruiting vegetables (tomatoes and peppers) can be bridged to this crop group and a nonfood use determination can be made based on the following: 1) as stated above, the data from 

Bedos (2002) suggest that leaf characteristics do not interfere with volatilization; thus, the 

difference in surface texture between fruiting vegetables and berries is not likely to affect residue 

profiles; 2) a 48-hour PHI would give ample time for volatilization of the constituents of tea tree 

oil from plant surfaces. Further, the PHI of 48 hours is further supported because residues of 

terpinen-4-ol were below the LOQ by 48 hours in the residue study where tea tree oil was 

applied at the 7X application rate; and 3) the limitation in the non-food use determination for tea 

tree oil would be that the active ingredient cannot be applied at more than 1.54 lbs a.i./acre, the 

level at which no detectable residues of tea tree oil were found. This information indicates that 

residues of tea tree oil are not likely to be present when these commodities are consumed. 

Tree nuts (group 14): even though residue data have not been submitted for tree nuts, the residue 

data on fruiting vegetables (tomatoes and peppers) can be bridged to this crop group and a nonfood use determination can be made based on the following: 1) as stated above, the data from 

Bedos (2002) suggest that leaf characteristics do not interfere with volatilization; thus, the 

difference in surface texture between fruiting vegetables and tree nuts is not likely to affect 

residue profiles; 2) a 48-hour PHI would give ample time for volatilization of the constituents of 

tea tree oil from plant surfaces. Further, the PHI of 48 hours is further supported because 

residues of terpinen-4-ol were below the LOQ by 48 hours in the residue study where tea tree oil 

was applied at the 7X application rate; and 3) the limitation in the non-food use determination for 

tea tree oil would be that the active ingredient cannot be applied at more than 1.54 lbs a.i./acre, 

the level at which no detectable residues of tea tree oil were found. This information indicates 

that residues of tea tree oil are not likely to be present when these commodities are consumed. 

Additionally, although not anticipated, if residues were available, they would be found on the 

shells of the nuts, which are not consumed. 

Cereal grains (group 15): even though residue data have not been submitted for cereal grains, the 

residue data on fruiting vegetables (tomatoes and peppers) can be bridged to this crop group and 

a non-food use determination can be made based on the following: 1) as stated above, the data 

from Bedos (2002) suggest that leaf characteristics do not interfere with volatilization; thus, the 

difference in surface texture between fruiting vegetables and cereal grains is not likely to affect 

residue profiles; 2) a 48-hour PHI would give ample time for volatilization of the constituents of 

tea tree oil from plant surfaces. Further, the PHI of 48 hours is further supported because 
Tea Tree Oil 

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Biopesticides Registration Action Document 

residues of terpinen-4-ol were below the LOQ by 48 hours in the residue study where tea tree oil 

was applied at the 7X application rate; and 3) the limitation in the non-food use determination for 

tea tree oil would be that the active ingredient cannot be applied at more than 1.54 lbs a.i./acre, 

the level at which no detectable residues of tea tree oil were found. This information indicates 

that residues of tea tree oil are not likely to be present when these commodities are consumed. 

Additionally, cereal grains are not typically consumed straight from the field and are processed 

and/or cooked prior to consumption which would further mitigate the potential for residues due 

to the increased time for volatilization and/or removal of tea tree oil’s constituents. 

Avocado, banana, mango, papaya, passion fruit, peanut, and plantain: residue data have been 

submitted for bananas which indicated that no residues were found at the proposed application 

rate. Even though residue data have not been submitted for the other crops, the residue data on 

fruiting vegetables (tomatoes and peppers) can be bridged to this crop group and a non-food use 

determination can be made based on the following: 1) as stated above, the data from Bedos 

(2002) suggest that leaf characteristics do not interfere with volatilization; thus, the difference in 

surface texture between fruiting vegetables and tree nuts is not likely to affect residue profiles; 2) 

a 48-hour PHI would give ample time for volatilization of the constituents of tea tree oil from 

plant surfaces. Further, the PHI of 48 hours is further supported because residues of terpinen-4-ol 

were below the LOQ by 48 hours in the residue study where tea tree oil was applied at the 7X 

application rate; and 3) the limitation in the non-food use determination for tea tree oil would be 

that the active ingredient cannot be applied at more than 1.54 lbs a.i./acre, the level at which no 

detectable residues of tea tree oil were found. This information indicates that residues of tea tree 

oil are not likely to be present when these commodities are consumed. Further, for the crops for 

which the skin is not consumed, (avocado, plantain, and peanuts), the potential for residues 

available at the time of consumption is further reduced. 

There is sufficient justification to support a non-food use determination for tea tree oil with 

limitations on the crops and crop groups identified previously in this document. The non-food 

use determination is based on the following: 1) the constituents of tea tree oil are very volatile 

which indicates that residues are not likely to be present in or on food; 2) no residues of the 

major constituents of tea tree oil were found on bananas, peppers, and tomatoes in residue 

studies at the proposed application rate for the rule; 3) a PHI of 48-hours is sufficient to 

compensate for the lack of residue data on the other listed crops and will provide ample time for 

dissipation of any residues; 4) the application rate limitation mitigates the potential for residues 

because no residues were found on bananas, peppers, and tomatoes at this application rate; 5) 

even if residues of tea tree oil’s constituents were found on edible crops they are not likely to be 

distinguishable from background levels since these substances are naturally found in plants; and 

6) washing, rinsing, and processing of commodities and weather events such as rain will further 

reduce any possibility for residues. 

Based on the analysis provided in this BRAD, the Agency concludes that use of tea tree oil in 

accordance with the limitations specified in the paragraph above will not result in residues on 

food. For the sake of transparency, the Agency intends to promulgate an amendment to 40 CFR § 

180.2020 to document this finding as follows: 
Tea Tree Oil 

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Biopesticides Registration Action Document 

Pesticide 

Chemical 

CAS Reg. No. Limits Uses 

Tea Tree Oil 68647-73-4 Post-harvest interval of 48 hours; maximum 

application rate of 1.54 lbs a.i./acre 

Fruiting vegetables (group 

8), leafy vegetables 

(group 4), cucurbit 

vegetables (group 9), 

berries (group 13), tree 

nuts (group 14), cereal 

grains (group 15), 

avocados, bananas, 

mangoes, papaya, passion 

fruit, peanuts, and 

plantains 

 b. Drinking Water Exposure and Risk Characterization 

Residues of the constituents of tea tree oil in drinking water are not expected when pesticide 

products are used according to label instructions. Tea tree oil and its constituents are expected to 

volatilize and degrade rapidly in the environment and are not directly applied to water; therefore, 

residues of tea tree oil in drinking water are unlikely. 

 c. Acute and Chronic Dietary Risks for Sensitive Subpopulations Particularly 

Infants and Children

The Agency has made a non-food use determination, with limitations, for the active ingredient, 

tea tree oil; therefore, there are no foreseeable dietary risks to sensitive subpopulations, including 

infants and children, from the use of tea tree oil in the proposed product when label instructions 

are followed. This conclusion is based on the following: 1) significant dietary exposure is not 

anticipated when label instructions for the proposed product are followed, 2) dietary risk to 

infants and children is anticipated to be negligible based on the results of the dietary risk 

assessments that the Agency has conducted (see Section IV.B.3.a above) and 3) humans are 

already exposed to tea tree oil in cosmetic and personal care products, and its major constituents 

are found naturally in the diet, in the environment, and are used as food additives. 

4. Occupational, Residential, School and Day Care Exposure and Risk Characterization 

 a. Occupational Exposure and Risk Characterization 

Dermal exposure to mixers/loaders and applicators is not anticipated as adequate PPE 

requirements are on the proposed EP label. Additionally, the active ingredient degrades rapidly 

in the environment which further mitigates dermal exposure. Due to the potential for inhalation 

exposure of residues of tea tree oil to mixers/loaders and applicators (the EP is applied as a 

spray, fog or drench), and the effects observed in the 90-day oral toxicity and prenatal 

developmental studies, an occupational exposure and risk assessment was conducted. The results 

of the risk assessment indicate that risk from inhalation exposure to tea tree oil is negligible for 

mixers/loaders and applicators when the pesticide product (Timorex Gold [EPA File Symbol No. 

86182-R]) is used according to label instructions. A summary of the assessment is provided 

below. 
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The assessment was conducted using a POD of 30 mg/kg bw/day (the NOAEL from the 90-day 

oral and developmental toxicity studies) and the occupational handler exposure calculation 

spreadsheet developed by OPP’s Health Effects Division (HED). Because 90-day inhalation 

toxicity data are not available, the Agency has bridged the data from the 90-day oral toxicity 

study and assumed 100% absorption via inhalation. The standard body weight for females (69 

kg) was used for all exposure scenarios in the assessment due to the incidence of developmental 

effects. Based on label instructions, exposure scenarios consisted of the following application 

methods: ground boom, airblast, aerial, and mechanically-pressured handgun. The application 

rate used for the exposure assessment was the maximum application rate on the label (1.6 lbs 

a.i./acre on a previously proposed label). Potential daily exposures for occupational handlers 

(mixer/loaders and applicators) were calculated in the spreadsheet using the following formulas: 

Daily exposure to the pesticide: 

Daily Exposure (mg ai /day) = UE (μg ai / lb ai) * AR (lb ai /A) * AT (A /day) * 1E-3 mg/μg 

Daily Exposure = amount of the active ingredient that is available for inhalation absorption, 

UE = Unit Exposure (generic values derived using measurements of exposure data in the field) 

AR = maximum application rate according to proposed label 

AT = daily acres treated. 

 

The average daily dose (daily exposure adjusted for absorption and body weight) was calculated 

using the following formula: 

Average Daily Dose (mg ai/kg/day) = [Daily Exposure (mg ai/day) * Absorption (%)] 

 Body Weight (kg) 

Average Daily Dose (ADD) = absorbed dose received from exposure to the active ingredient in a 

given scenario 

Daily Exposure = amount of the active ingredient that is available for inhalation absorption 

Absorption Factor = a measure of the amount of chemical that crosses a biological boundary 

such as the skin and lungs (%) 

Body Weight = body weight determined to represent the population of interest in a risk 

assessment 

Risk for each application handler scenario was calculated using a MOE, which is a ratio of the 

toxicological endpoint to the daily dose of concern. The daily inhalation dose received by 

occupational handlers was compared to the POD (i.e.: NOAEL) to assess the risk to occupational 

handlers. All MOE values were calculated using the following formula: 

MOE = POD (i.e.: NOAEL in mg/kg/day) 

 ADD (mg/kg/day) 

All MOEs calculated for mixers/loaders and applicators using no inhalation PPE were 

significantly greater than the Agency’s LOC of 100 (10X for intraspecies variation and 10x for 
Tea Tree Oil 

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Biopesticides Registration Action Document 

interspecies variation). MOEs greater than 100 do not exceed the Agency’s LOC; therefore, risks 

are not considered to be of concern. Based on the results of the occupational risk assessment, 

unreasonable adverse effects to handlers are not anticipated when the pesticide product is used 

according to label instructions. A summary of the exposure scenarios and MOEs is provided in 

Table 3 below. 

 

Significant post-application exposure to tea tree oil is not anticipated as there is a 24-hour REI on 

the EP label and the active ingredient is expected to rapidly degrade in the environment. 

 b. Residential, School and Day Care Exposure and Risk Characterization 

Significant exposure to tea tree oil is not anticipated in residential, school, and day care areas, as 

the product containing this active ingredient is intended for use on horticultural and agricultural 

crops.

5. Aggregate Exposure from Multiple Routes Including Dermal, Oral, and Inhalation 

There is reasonable certainty that no harm to the U.S. population will result from aggregate 

exposure to tea tree oil. This includes all exposures for which there is reliable information. The 

Agency arrived at this conclusion based on the following: 1) the non-food use determination, 

with limitations, for the active ingredient, tea tree oil, 2) residential exposures are not anticipated 

based on the pesticidal use pattern of tea tree oil, 3) drinking water exposure is not anticipated 

based on the rapid degradation of the active ingredient in the environment and tea tree oil is not 

directly applied to water. The risks from aggregate exposure via oral, dermal, and inhalation 

exposure are a compilation of three low-risk exposure scenarios and are negligible. 

6. Cumulative Effects

Section 408(b)(2)(D)(v) of FFDCA requires that, when considering whether to establish, modify, 

or revoke a tolerance, the Agency consider “available information” concerning the cumulative 

TABLE 3. Occupational Risk Assessment Summaries for Tea Tree Oil (Inhalation Route of Exposure)

Worker Activity Application Equipment/Application Type Application Type MOE 

Mixer/Loader Aerial/Broadcast Orchard 17,000 

Mixer/Loader Aerial/Broadcast Field crop, typical 17,000 

Mixer/Loader Aerial/Broadcast Field crop, high-acreage 4,900 

Mixer/Loader Airblast/Broadcast Orchard 150,000 

Mixer/Loader Groundboom/Broadcast Field crop, typical 74,000 

Mixer/Loader Groundboom/Broadcast Field crop, high-acreage 29,000 

Applicator Aerial/Broadcast Orchard Exposure not anticipated 

Applicator Aerial/Broadcast Field crop, typical Exposure not anticipated 

Applicator Aerial/Broadcast Field crop, high-acreage Exposure not anticipated 

Applicator Airblast/Broadcast Orchard 6,900 

Applicator Groundboom/Broadcast Field crop, typical 48,000 

Applicator Groundboom/Broadcast Field crop, high-acreage 19,000 

Flagger Aerial/Broadcast Orchard 11,000 

Flagger Aerial/Broadcast Field crop, typical 11,000 

Flagger Aerial/Broadcast Field crop, high-acreage 11,000 
Tea Tree Oil 

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Biopesticides Registration Action Document 

effects of a particular pesticide’s residues and “other substances that have a common mechanism 

of toxicity.” EPA has not found tea tree oil to share a common mechanism of toxicity with any 

other substances, and tea tree oil does not appear to produce a toxic metabolite produced by other 

substances. For the purposes of this tolerance action, therefore, EPA has assumed that tea tree oil 

does not have a common mechanism of toxicity with other substances. For information regarding 

EPA’s efforts to determine which chemicals have a common mechanism of toxicity and to 

evaluate the cumulative effects of such chemicals, see EPA’s website at 

http://www.epa.gov/pesticides/cumulative. 

7. Risk Characterization 

The Agency has considered human exposure to tea tree oil in light of the relevant safety factors 

in FQPA and FIFRA. A determination has been made that no unreasonable adverse effects to the 

U.S. population in general, and to infants and children in particular, will result from the use of 

tea tree oil as a pesticide when label instructions are followed. 

C. Environmental Assessment 

1. Ecological Hazards 

Adequate nontarget toxicology data/information is available to support registration of tea tree oil 

with the submission of nontarget toxicology data on the TGAI. All nontarget toxicology data 

requirements for tea tree oil have been satisfied.

Tea tree oil is highly toxic to aquatic invertebrates. Tea tree oil is practically nontoxic to fish and 

insects. Tea tree oil is not phytotoxic. Significant exposure of tea tree oil to birds is not expected 

due to volatilization and rapid degradation of the active ingredient in the environment (EPA, 

2013). 

For more information regarding nontarget organism toxicity data requirements, refer to Table 8 

in Appendix A. 

2. Environmental Fate and Ground Water Data 

Tea tree oil is expected to degrade rapidly in the environment. Up to 90% of tea tree oil has been 

shown to volatilize within 24 hours after application and residue studies indicate the lack of 

detectable residues of three of the major constituents of tea tree oil at 48 hours post-application 

(EPA, 2013). In MRID 48275004, a study was submitted in which the biodegradation of tea tree 

oil was determined in a 28-day ready biodegradability assay (OECD Guideline 310 and EN ISO 

14593) by monitoring the release of carbon dioxide with a non-adapted activated sewage sludge. 

Based on the results of the assay, biodegradation of tea tree oil was 10% after 2 days, 60% after 

5 days, 87% by day 7, and 106% at study termination. 
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Biopesticides Registration Action Document 

3. Ecological Exposure and Risk Characterization

Significant exposure to birds is not expected because the active ingredient is volatile and 

degrades rapidly in the environment. Additionally, birds are already exposed to the components 

of tea tree oil, as they are present in a multitude of plants. Although exposure to fish, insects, and 

plants is anticipated from use of the product through direct application, accidental application, 

drift or run-off, results of toxicity testing on pure tea tree oil indicate that tea tree oil is 

practically nontoxic to these organisms. The proposed EP which contains 23.8% tea tree oil will 

also be diluted with water prior to application, which will further reduce exposure to these 

organisms. The aquatic invertebrate toxicity study submitted indicates that tea tree oil is highly 

toxic to these organisms. Because of the potential for toxicity to freshwater invertebrates, a risk 

assessment for these organisms was conducted for the EP based on nontarget organism 

toxicology data on the EP (EPA, 2014a). The results of the risk assessment for the EP indicated 

that mitigation language for aquatic invertebrates is required on the EP label. 

4. Endangered Species Assessment 

The Agency has not conducted a risk assessment that supports a complete endangered species 

determination. The ecological risk assessment planned during registration review will allow the 

Agency to determine whether tea tree oil’s use has “no effect” or “may effect” federally listed 

threatened or endangered species (listed species) or their designated critical habitats. When an 

assessment concludes that a pesticide’s use “may affect” a listed species or its designated critical 

habitat, the Agency will consult with the U.S. Fish and Wildlife Service and/or National Marine 

Fisheries Services (the Services) as appropriate. 

 

D. Product Performance Data 

Product performance data must be developed for all pesticides to ensure that pesticide products 

will perform as intended and that unnecessary pesticide exposure to the environment will not 

occur as a result of the use of ineffective products. The Agency reserves the right to require on a 

case-by-case basis, submission of efficacy data for any pesticide product registered or proposed 

for registration that are intended to be used to control a pest of significance public health 

importance and a public health pest as defined in FIFRA section 28(d) and section 2(nn). For 

further guidance on product performance requirement, refer to Pesticide Registration Notice (PR) 

Notices 96-7, 2002-1 and Explanation of Statutory Framework for Risk-Benefit Balancing for 

Public Health Pesticides (http://www.epa.gov/PR _Notices/pr1996-7.pdf) 

(http://www.ea.gov/PR_Notices/pr2002-1.pdf) and (http://www.epa.gov/pesticides/health/riskbenefit.htm). 

The EP submitted with this new active ingredient did not list pests of significant public health 

importance or a public health pest as defined in FIFRA section 28(d) and section 2(nn). 

Therefore, product performance (efficacy) was not evaluated. 
Tea Tree Oil 

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Biopesticides Registration Action Document 

V. RISK MANAGEMENT DECISION

A. Determination of Eligibility for Registration 

Section 3(c)(5) of FIFRA provides for the registration of a new active ingredient if it is 

determined that: (A) its composition warrants proposed claims; (B) its labeling and other 

materials comply with the requirements of FIFRA; (C) it will perform its intended function 

without unreasonable adverse effects on the environment; and (D) when used in accordance with 

widespread and commonly recognized practice, it will not generally cause unreasonable adverse 

effects on the environment. 

The four criteria of the Eligibility Determination for Pesticidal Active Ingredients are satisfied by 

the science assessments supporting products containing the TGAI, tea tree oil. Such products are 

not expected to cause unreasonable adverse effects. Therefore, tea tree oil as a TGAI is eligible 

for registration for the labeled uses. 

B. Regulatory Decision 

The data submitted fulfill the registration requirements of tea tree oil for use as a 

fungicide/bactericide. Refer to Appendix B for product-specific information. 

 Conditional/Unconditional Registration

All data requirements are fulfilled, and EPA determined that an unconditional registration of tea 

tree oil is appropriate.

C. Environmental Justice 

EPA seeks to achieve environmental justice—the fair treatment and meaningful involvement of 

all people regardless of race, color, national origin, or income—with respect to the development, 

implementation, and enforcement of environmental laws, regulations, and policies. At this time, 

EPA does not believe that use of tea tree oil pesticide products will cause harm or a 

disproportionate impact on at-risk communities. For additional information regarding 

environmental justice issues, please visit EPA’s website at 

http://www.epa.gov/compliance/environmentaljustice/index.html. 

VI. ACTIONS REQUIRED BY REGISTRANTS

EPA evaluated all data submitted in connection with the registration of the tea tree oil pesticide 

products and determined that these data are sufficient to satisfy current registration data 

requirements. At this time, no additional data must be submitted to EPA for these particular 

products. For new uses and/or changes to existing uses, EPA may require additional data. 

Notwithstanding the information stated in the previous paragraph, it should be clearly understood 

that certain specific data are required to be reported to EPA as a requirement for maintaining the 
Tea Tree Oil 

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Biopesticides Registration Action Document 

Federal registration for a pesticide product. A brief summary of these types of data are listed 

below. 

A. Reporting of Adverse Effects 

Pursuant to FIFRA section 6(a)(2), reports of all incidents of adverse effects to the environment 

must be submitted to EPA. 

B. Reporting of Hypersensitivity Incidents 

Additionally, all incidents of hypersensitivity (including both suspected and confirmed incidents) 

must be reported to the Agency under the provisions of 40 CFR Part 158.2050(d). 

VII. APPENDIX A. DATA REQUIREMENTS (40 CFR PART 158-SUBPART U) 

*NOTE: Master Record Identification (MRID) numbers listed in the following tables are 

representative of supporting data/information for the original registration of the product 

containing this active ingredient. Subsequent to this registration, there may be additional MRIDs 

that support registration of other products containing this active ingredient. 

TABLE 4. Product Chemistry Data Requirements for Tea Tree Oil (40 CFR § 158.2030)

OCSPP Guideline Reference No./Study Description of Result MRID 

880.1100 Product identity and composition The product identity and composition were 

adequately addressed. Confidential Business 

Information (CBI). 

47730401 

880.1200 Description of starting materials, 

production, and formulation 

process 

The description of the starting materials, 

production, and formulation process were 

adequately addressed. CBI. 

47730401 

880.1400 Discussion of formation of 

impurities 

The discussion of formation of impurities was 

adequately addressed. CBI. 47730401 

830.1700 Preliminary analysis The preliminary analysis of the product was 

acceptable. CBI. 47730402, 47730403 

830.1750 Certified limits The certified limits listed on the CSF are 

acceptable. 47730401 

830.1800 Enforcement analytical method The enforcement analytical method was 

adequately addressed. CBI. 47730401
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Biopesticides Registration Action Document 

TABLE 5. Physical and Chemical Properties for Tea Tree Oil (40 CFR § 158.2030)

OCSPP Guideline Reference No./Property Description of Result MRID 

830.6302 Color Colorless to pale yellow 47730401 

830.6303 Physical State Liquid 47730401

830.6304 Odor Characteristic 47730401

830.6313 Stability to normal and elevated 

temperatures, metals and metal 

ions 

Decomposition temperature is expected to be 

>200°C (based on values for the individual 

components). 

Generally stable to galvanized steel 

(packaging material) over 8 months at 

ambient warehouse storage, 10-35 ̊C. 

47730401 

Correspondence 

between Canada’s Pest 

Management 

Regulatory Agency 

(PMRA) and TSG 

dated May 11, 2009 

and PMRA product 

chemistry review.

830.6315 Flammability Flashpoint = 55°C 

 59°C 

47918402 

47730401

830.6317 Storage Stability Composition of TGAI may vary considerably 

during storage, with ρ-cymene levels 

increasing and α- and γ-terpinene levels 

decreasing. Light, heat, air exposure and 

moisture affect oil stability. The MP should be 

stored in dark, cool, dry conditions in an 

airtight container. 

During the 8 month study, of the 5 major 

components, α-terpinene decreased ~13% and 

ρ-cymene increased ~15.5%, with the other 

three not changing significantly. 

Correspondence 

between PMRA and 

TSG dated May 11, 

2009, and PMRA 

product chemistry 

review. 

830.6319 Miscibility Not applicable, the product is not to be mixed 

with petroleum solvents. 

47730401

830.6320 Corrosion Characteristics Generally stable to galvanized steel 

(packaging material) over 8 months at 

ambient warehouse storage, 10-35 ̊C. No 

visual changes (corrosion, color change) were 

observed. 

Correspondence 

between PMRA and 

TSG dated May 11, 

2009, and PMRA 

product chemistry 

review.

830.7000 pH Not applicable 47730401

830.7050 UV/Visible light absorption In propan-2-ol, a single maximum at 265 nm 

was observed.

47730409 and 

47918403 

830.7100 Viscosity 2.47 cSt at 25oC 48275001 

830.7200 Melting Range Not applicable, the product is a liquid. 47730401

830.7220 Boiling Range Expected to be ca. 200°C (derived from 

values of the individual components) 

47730401

830.7300 Density/Relative Density/Bulk 

Density 

Minimum density = 0.885 g/mL at 20°C 

Maximum density = 0.906 g/mL at 20°C 

47730401

830.7520 Particle size, fiber length, and 

diameter distribution 

Not known for TGAI. Relevant components 

of TGAI are not expected to dissociate. 

47730401 and 

47730409
Tea Tree Oil 

Page 26 of 32 

Biopesticides Registration Action Document 

TABLE 5. Physical and Chemical Properties for Tea Tree Oil (40 CFR § 158.2030)

OCSPP Guideline Reference No./Property Description of Result MRID 

830.7550 Partition Coefficient (n-Octanol/ 

830.7560 Water) 

830.7570 

Not known for TGAI. 

 Component log Kow

terpinen-4-ol 2.643 

 3.33 

γ-terpinene 4.47 

α-terpinene 4.75 

p-cymene 4.44 

1,8-cineole 3.13 

47730401 and 

47730409

830.7840 Water Solubility Not known for TGAI. 

Component Temp ( ̊C) Solubility 

terpinen-4-ol - 1767 mg/L 

γ -terpinene 22-25 8.72 mg/L 

α-terpinene - 5.92 mg/L 

p-cymene - 5.0 mg/L 

1,8-cineole - 552 mg/L 

47730401 and 

47730409

830.7950 Vapor Pressure Not known for TGAI. 

Component Temp ( ̊C) VP (Pa) 

terpinen-4-ol 20 53.2 

-terpinene 20 93.1 

 23.5 103 

α-terpinene 20 106.4 

p-cymene 25 199.5 

1,8-cineole 25 253 

47730401 and 

47730409
Tea Tree Oil 

Page 27 of 32 

Biopesticides Registration Action Document 

Table 6: Mammalian Toxicology Data Requirements for Tea Tree Oil (40 CFR § 158.2050)

Study/OCSPP Guideline No. Results Toxicity 

Category/Description MRID 

Acute oral toxicity (rat) 

(870.1100) 

LD50 = 1752 mg/kg (1752-2450 mg/kg) Toxicity Category III 47730404 

Acute dermal toxicity (rat) 

(870.1200) 

LD50 > 2000 mg/kg Toxicity Category III 47730404 

Acute inhalation toxicity (rat) 

(870.1300) 

LC50 = 3.64 mg/L Toxicity Category IV 48598701 

48878201 

Primary eye irritation (rabbit) 

(870.2400) 

Waived: MP is corrosive to skin. 

A chorioallantioic membrane vascular assay 

(chicken egg) was submitted, but is 

unacceptable as EPA has not established this 

assay to be appropriate to fulfill the primary 

eye irritation data requirement. 

Toxicity Category I 

47730405 

Primary dermal irritation (rabbit) 

(870.2500) 

Corrosive. Well-defined to severe erythema 

and barely perceptible to slight edema were 

noted on the intact sites of 6/6 rabbits at the 

24- and 72-hour evaluations. Well-defined 

to severe erythema and barely perceptible to 

moderate edema were noted on the abraded 

sites of 6/6 rabbits at the 24 and 72 hour 

evaluations. Three animals had erosion on 

abraded sites at the 72-hour evaluation. The 

primary irritation index (PII) was 5.0. 

Toxicity Category I 

47730404 

Dermal sensitization (guinea pig) 

(870.2600) 

Waived: MP is corrosive to skin. 

A skin sensitization study was submitted. 

After intradermal and epidermal inductions, 

the test and control animals showed no signs 

of reactivity 24 hours after challenge. 

However, study classification is 

unacceptable due to the lack of positive 

control data. 

- 

47730404 

90-Day oral toxicity 

(870.3100) 

LOAEL = 60 mg/kg/day based on testicular 

toxicity in males and increased liver to body 

weight ratios in females 

NOAEL = 30 mg/kg/day for males and 

females 

- 

48598702 

48878202 

90-Day dermal toxicity 

(870.3250) 

Waived: prolonged dermal exposure not 

anticipated. TGAI is corrosive to skin and 

adequate PPE is required on the label. 

Undiluted tea tree oil caused severe 

irritation to the skin on the first day of a 

non-guideline 30-day dermal irritation study 

on rabbits. For the remainder of the study, a 

25% solution in paraffin oil was applied to 

the skin which did not result in visible 

irritation; however, non-specific 

microscopic dermatitis consistent with 

irritation was observed. 

- 

47730411 

47730404

90-Day inhalation toxicity 

(870.3465) 

The data from the 90-data oral toxicity study 

has been bridged to satisfy this data 

requirement. A route to route extrapolation 

will be employed using a 100% absorption 

assumption. 

- 

48598704 

48878201
Tea Tree Oil 

Page 28 of 32 

Biopesticides Registration Action Document 

Table 6: Mammalian Toxicology Data Requirements for Tea Tree Oil (40 CFR § 158.2050)

Study/OCSPP Guideline No. Results Toxicity 

Category/Description MRID 

Developmental toxicity 

 (870.3700) 

Maternal: 

NOAEL = 30 mg/kg/day 

LOAEL = 60 mg/kg/day based on treatment 

related decreased body weight gain and food 

intake 

Developmental: 

NOAEL = 60 mg/kg/day 

LOAEL = 120 mg/kg/day based on 

decreased fetal weights 

- 49166401 

Mutagenicity – Tier I 

(870.5100, 5300 and 5375) 

Mutagenicity – Tier II 

(870.5395) 

Not mutagenic in Salmonella reverse 

mutation assay at doses below 50 μg. 

Negative in in vivo mouse bone marrow 

micronucleus assay. 

- 

47730404 

47730407 

47730409 

Table 7: Nontarget Organism Toxicity Data Requirements for Tea Tree Oil (40 CFR § 158.2060)

Study/OCSPP Guideline No. Results Toxicity 

Category/Description MRID 

Avian acute oral toxicity 

 (850.2100) 

Adequate information to support data 

requirement: significant exposure to birds is 

not expected due to volatilization and rapid 

degradation of the active ingredient in the 

environment. Additionally, components of 

the TGAI are already found in a multitude of 

plants. 

Significant exposure 

not expected 

47730411 

Avian dietary toxicity 

(850.2200) 

Adequate information to support data 

requirement: significant exposure to birds is 

not expected due to volatilization and rapid 

degradation of the active ingredient in the 

environment. Additionally, components of 

the TGAI are already found in a multitude of 

plants. 

Significant exposure 

not expected 

47730411 

Aquatic invertebrate acute 

toxicity, freshwater 

 (850.1010) 

48-hour EC50 = 0.591 mg/L 

(95% CL: 0.499-0.700 mg/L) Highly toxic 48598703

Fish acute toxicity, freshwater 

(850.1075) 

LC50 > 100 mg/L Practically non-toxic 

47730408 

Terrestrial plant toxicity, Seedling 

emergence/Vegetative vigor 

(850.4100 and 850.4150) 

Adequate information to support data 

requirement: using the proposed EP in 

efficacy trials on squash, potatoes, apples, 

no phytotoxicity was observed. Minor 

phytotoxicity was observed in one South 

African grape variety (brown spots) in one 

trial; however, in nine other trials in grapes 

no phytotoxicity was observed. Minor 

phytotoxicity was observed in one trial in 

tomatoes and cucumbers (small necrotic 

spots); however, no phytoxicity was 

observed in eleven other trials in tomatoes. 

The components of tea tree oil are volatile 

and are also already found in a multitude of 

plants. 

Not phytotoxic 47730521 

Nontarget insect testing Apis millifera: oral LD50 > 98.5 μg a.i./bee; 477305201
Tea Tree Oil 

Page 29 of 32 

Biopesticides Registration Action Document 

Table 7: Nontarget Organism Toxicity Data Requirements for Tea Tree Oil (40 CFR § 158.2060)

Study/OCSPP Guideline No. Results Toxicity 

Category/Description MRID 

(880.4350) contact LD50 > 331 μg a.i./bee 

Bombus terrestris: oral LD50 > 105.49 μg 

a.i./bee; contact LD50 > 100 μg a.i./bee 

Aphidius rhopalosiphi: ER50 and LR50 

>1.08 L EP/ha 

Typhlodromus pyri: ER50 = 1.78 L EP/ha 

(95% c.i., 1.54-2.09 L EP/ha); 7d LR50 

>4.32 L EP/ha

Practically non-toxic 477305192

477305183

477305173

1Study conducted on the proposed EP, Timorex Gold (EPA File Symbol No. 86182-R), at target doses of 100 μg a.i./bee (oral) 

and 18, 32, 56, 100, 180, and 320 μg a.i./bee (contact) 2 Study conducted on the proposed EP, Timorex Gold (EPA File Symbol No. 86182-R), at a target dose of 100 μg a.i./bee 

(nominally equivalent to 423.73 μg EP/bee) 3 Supplemental data. Values reported are based on the proposed EP, Timorex Gold (EPA File Symbol No. 86182-R), and have 

not been corrected for active ingredient concentration. 

VIII. APPENDIX B. 

For product specific information, please refer to http://www.epa.gov/pesticides/pestlabels. 

IX. APPENDIX C. 

REFERENCES 

Bedos C, Cellier P, Calvet R, et. al. (2002) Mass transfer of pesticides into the atmosphere by 

volatilization from soils and plants: overview. Agronomie 22: 21-33. 

Chadwick G. (2008). Final Report on Project AF/12583/BB. Agrisearch UK Ltd. Laboratory 

Project ID AF/12583/BB. September 18, 2008. MRID 47730522. 

EPA. 2010. Memorandum from Angela L. Gonzales to Colin Walsh. Joint Science Review with 

Health Canada Pest Management Regulatory Agency (PMRA) In Support of the Registration of 

Tea Tree Oil Technical containing Tea Tree Oil as its active ingredient. U.S. Environmental 

Protection Agency Office of Pesticide Programs. February 28, 2010. 

EPA. 2013. Memorandum from Angela L. Gonzales thru Felecia A. Fort to Colin Walsh. Joint 

Science Review with Health Canada Pest Management Regulatory Agency In Support of the 

Registration of Tea Tree Oil Technical Containing Tea Tree Oil as its Active Ingredient. U.S. 

Environmental Protection Agency Office of Pesticide Programs. January 30, 2013. 

EPA. 2014a. Memorandum from Angela L. Gonzales to Colin Walsh. Science Review In 

Support of the Registration of Tea Tree Oil Technical Containing Tea Tree Oil as its Active 

Ingredient. U.S. Environmental Protection Agency Office of Pesticide Programs. April 10, 2014. 

EPA. 2014b. Memorandum from Angela L. Gonzales to Linda A. Hollis. Nonfood-Use 
Tea Tree Oil 

Page 30 of 32 

Biopesticides Registration Action Document 

Determination In Support of the Registration of Tea Tree Oil Technical Containing Tea Tree Oil 

as its Active Ingredient. U.S. Environmental Protection Agency Office of Pesticide Programs. 

July 23, 2014. 

European Food Safety Authority (EFSA). (2012). Conclusion on the peer review of the pesticide 

risk assessment of the active substance extract from tea tree. EFSA Journal: 10(2):2542. 

http://www.efsa.europa.eu/en/efsajournal/doc/2542.pdf. 

Gatenio I, Ofer D. (2007). Determination of Tea Tree Oil Residues in Grapes (Treated with BM 

608). Bactochem. January 11, 2007. MRID 47730523. 

Henley DV, Lipson N, Korach KS, Block CA. 2007. Prepubertal gynecomastia linked to 

lavender and tea tree oils. N Engl J Med.; 356(5): 479-85 

Pest Management Regulatory Agency (PMRA). Health Canada. (2014). Evaluation Report 

ERC2014-01, Tea Tree Oil. Catalogue number: H113-26/2014-1E-PDF. http://www.hcsc.gc.ca/cps-spc/pubs/pest/_decisions/erc2014-01/index-eng.php. 

REVIEWS AND OTHER REFERENCES 

EPA. 2010. Memorandum from Angela L. Gonzales to Colin Walsh. Joint Science Review with 

Health Canada Pest Management Regulatory Agency (PMRA) In Support of the Registration of 

Timorex Gold containing Tea Tree Oil as its active ingredient. U.S. Environmental Protection 

Agency Office of Pesticide Programs. February 28, 2010. 

EPA. 2013. Memorandum from Angela L. Gonzales to Colin Walsh. Joint Science Review with 

Health Canada Pest Management Regulatory Agency (PMRA) In Support of the Registration of 

Timorex Gold containing Tea Tree Oil as its active ingredient. U.S. Environmental Protection 

Agency Office of Pesticide Programs. January 30, 2013. 

EPA. 2014. Memorandum from Angela L. Gonzales to Colin Walsh. Science Review in Support 

of the Registration of Timorex Gold containing Tea Tree Oil as its Active Ingredient. U.S. 

Environmental Protection Agency Office of Pesticide Programs. April 10, 2014.

X. GLOSSARY OF ACRONYMS AND ABBREVIATIONS 

a.i. active ingredient 

ARS Agricultural Research Service (USDA) 

Biomor Biomor Israel, Ltd. 

BPPD Biopesticides and Pollution Prevention Division 

BRAD Biopesticide Registration Action Document 

bw body weight 

CBI Confidential Business Information 

CFR Code of Federal Regulations 

cm3

 cubic centimeter 
Tea Tree Oil 

Page 31 of 32 

Biopesticides Registration Action Document 

CSF Confidential Statement of Formula 

cSt centistokes 

°C degrees Celsius 

DEEM-FCID Dietary Exposure Evaluation Model - Food Commodity Intake Database 

EC50 median effective concentration. A statistically derived single concentration in 

environmental medium that can be expected to cause an effect in 50% of the test 

animals when administrated by the route indicated (inhalation). It is expressed 

as a concentration in air or water (e.g. mg/L). 

EDSP Endocrine Disruptor Screening Program 

EDSTAC Endocrine Disruptor Screening and Testing Advisory Committee 

EP end-use product 

EPA Environmental Protection Agency (the “Agency”) 

FDA U.S. Food and Drug Administration 

FFDCA Federal Food, Drug, and Cosmetic Act 

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act 

FQPA Food Quality Protection Act 

FR Federal Register 

g gram 

ha hectare 

kg kilogram 

Kow octanol-water partition coefficient 

L liter 

LC50 median lethal concentration. A statistically derived single concentration in air or 

water that can be expected to cause death in 50% of the test animals when 

administrated by the route indicated (inhalation and environment). It is 

expressed as a concentration in air or water (e.g. mg/L). 

LD50 median lethal dose. A statistically derived single dose that can be expected 

 to cause death in 50% of the test animals when administered by the route 

 indicated (oral and dermal). It is expressed as a weight of 

 substance per unit weight of animal (e.g., mg/kg). 

LOAEL lowest-observed-adverse-effect-level 

LOC level of concern 

LOQ limit of quantification 

MOE margin of exposure 

MRID No. Master Record Identification Number 

mg milligram 

mPa millipascal 

mL milliliter 

MP manufacturing-use product 

N/A not applicable 

NE “No Effect” 

nm nanometer 

NOAEL no-observed-adverse-effect-level 

NOEL no-observed-effect-level 

NOF notice of filing 

NOR notice of receipt 
Tea Tree Oil 

Page 32 of 32 

Biopesticides Registration Action Document 

OPP Office of Pesticide Programs 

OCSPP Office of Chemical Safety and Pollution Prevention 

pa pascal 

PHI pre-harvest interval 

PMRA Canada’s Pesticide Management Regulatory Authority 

POD point of departure 

PPE personal protective equipment 

PR Notice Pesticide Registration Notice 

REI restricted-entry interval 

RfD reference dose 

 TGAI technical grade of the active ingredient 

 TSG Technology Sciences Group, Inc. 

 UF uncertainty factor 

 ug microgram 

 USDA United States Department of Agriculture 

 UV ultra-violet