The following Pesticide Hazard Tricolour (PHT) alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement. The alerts for Highly Hazardous Pesticides (HHPs) are based on applying the FAO/WHO (Type 1) and the PAN (Type II) criteria to PPDB data. Further details on the HHP indicators are given in the tables below. Neither the PHT nor the HHP hazard alerts take account of usage patterns or exposure, thus they do not represent risk.
No UK approval for use as a plant protection agent
EC Regulation 1107/2009 (repealing 91/414)
EC Regulation 1107/2009 status
Approved
Dossier rapporteur/co-rapporteur
Poland/Belgium
Date EC 1107/2009 inclusion expires
31/01/2026
EU Candidate for substitution (CfS)
No
Listed in EU database
Yes
Approved for use (✓) under EC 1107/2009 in the following EU Member States
ATAustria
BEBelgium
BGBulgaria
CYCyprus
CZCzech Republic
DEGermany
DKDenmark
EEEstonia
ELGreece
ESSpain
FIFinland
FRFrance
HRCroatia
HUHungary
IEIreland
ITItaly
LTLithuania
LULuxembourg
✓
LVLatvia
MTMalta
NLNetherlands
PLPoland
PTPortugal
RORomania
SESweden
SISlovenia
SKSlovakia
Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries
ISIceland
NONorway
Additional information
Also used in
Morocco
Chemical structure
Isomerism
Tea tree oil is a complex natural and many of its constituents exhibit both structural and stereoisomeric isomerism. These include the three structural isomers of terpinene, terpinen-4-ol that is part of a family of compounds that includes optical isomers, cineole that is known to have stereoisomeric forms and the structural isomers of pinene.
Chemical formula
-
Canonical SMILES
-
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
-
International Chemical Identifier (InChI)
-
2D structure diagram/image available?
No
General status
Biopesticide type
Fungicide
Other bioactivity & uses
Antimicrobial
Substance groups
Plant-derived substance; Plant oil
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Natural; Complex mixture
Mode of action
Via the disruption of the structural and functional integrity of bacterial membrane, inhibiting the formation of germ tubes, or mycelial conversion and by suppressing superoxide production
Substance source
Extracted for the Tea tree shrub (Melaleuca alternifolia), a species of tree or tall shrub in the myrtle family
Mixture composition
Tea tree oil is a complex mixture of over 100 volatile compounds, predominantly monoterpenes, sesquiterpenes, and their oxygenated derivatives. Its composition is standardised by the international norm ISO 4730:2017 ("Oil of Melaleuca, terpinen-4-ol type"), which defines acceptable ranges for key components to ensure quality and consistency in commercial products. The dominant and most biologically active constituent is terpinene-4-ol (35-48%). Other major components include: gamma-terpinene (14-28%), alpha-terpinene (6-12%), 1,8-vineole ( traces to 10%), terpinolene (1.5–5%), p-cymene (0.5-8%), alpha-pinene (1-6%) and alpha-terpineol (2-8%). Minor but notable sesquiterpenes include aromadendrene (0.2-3%), ledene/viridiflorene (0.1-3%).
Pale straw coloured liquid comprised of a complex nd variable mixture of botanicl chemicals including terpinen-4-ol (35 to 45%), gamma-terpinene (14 to 28%), alpha-terpinene (6 to 12%) and 1,8-cineole (0 to 10%)
Example manufacturers & suppliers of products using this active now or historically
Syngenta AG
Summit Agro USA
Example products using this active
Formulation and application details
Often formulated as liquid concetrates and ready-to-use products
Commercial production
The oil is produced through steam distillation of the leaves and terminal branchlets of the tea tree shrub (Melaleuca alternifolia)
Impact on climate of production and use
While specific data for tea tree oil is scarce, similar essential oils (like eucalyptus or lavender) have estimated carbon footprints ranging from 1.5 to 5 kg CO₂e per kg of oil, depending on farming practices and energy sources used in distillation. This is in line with general data for plant oils which have been estimated at between 1.0 and 4.0 kg CO₂e per kg of oil.
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C at pH 7 (mg l⁻¹)
-
-
-
Solubility - In organic solvents at 20 °C (mg l⁻¹)
-
-
-
Melting point (°C)
-
-
-
Boiling point (°C)
-
-
-
Degradation point (°C)
-
-
-
Flashpoint (°C)
39
E4 E = Manufacturers safety data sheets 4 = Verified data
-
Octanol-water partition coefficient at pH 7, 20 °C
P
-
-
-
Log P
-
-
-
Fat solubility of residues
Solubility
-
-
-
Data type
-
-
-
Density (g ml⁻¹)
0.925
E4 E = Manufacturers safety data sheets 4 = Verified data
-
Dissociation constant pKa) at 25 °C
-
-
-
-
Vapour pressure at 20 °C (mPa)
-
-
-
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
-
-
-
Volatilisation as max % of applied dose lost
From plant surface
-
-
-
From soil surface
-
-
-
Maximum UV-vis absorption L mol⁻¹ cm⁻¹
-
-
-
Surface tension (mN m⁻¹)
-
-
-
Degradation
Property
Value
Source; quality score; and other information
Interpretation
General biodegradability
Readily biodegradable
Soil degradation (days)
DT₅₀ (typical)
-
-
-
DT₅₀ (lab at 20 °C)
-
-
-
DT₅₀ (field)
-
-
-
DT₉₀ (lab at 20 °C)
-
-
-
DT₉₀ (field)
-
-
-
DT₅₀ modelling endpoint
-
-
-
Note
-
Soil mineralisation
Aerobic (at 20 °C)
-
-
-
Anaerobic (at 20 °C)
-
-
Dissipation rate RL₅₀ (days) on plant matrix
Value
-
-
-
Note
-
Dissipation rate RL₅₀ (days) on and in plant matrix
Value
-
-
-
Note
-
Aqueous photolysis DT₅₀ (days) at pH 7
Value
-
-
-
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
-
-
-
Note
-
Water-sediment DT₅₀ (days)
-
-
-
Water phase only DT₅₀ (days)
-
-
-
Sediment phase only DT₅₀ (days)
-
-
-
Air degradation
As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.
Decay in stored produce DT₅₀
-
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd (mL g⁻¹)
-
-
-
Koc (mL g⁻¹)
-
Notes and range
-
Freundlich
Kf (mL g⁻¹)
-
-
-
Kfoc (mL g⁻¹)
-
1/n
-
Notes and range
-
pH sensitivity
-
Known metabolites
None
ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 2000
E4 E = Manufacturers safety data sheets 4 = Verified data
Rat
Low
Mammals - Short Term Oral NOAEL (mg kg⁻¹ bw d⁻¹)
-
-
-
Mammals - Long Term (Chronic) Oral NOAEL (mg kg⁻¹ bw d⁻¹)
-
-
-
Birds - Acute LD₅₀ (mg kg⁻¹)
> 2000
R4 R = Peer reviewed scientific publications 4 = Verified data
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
> 331
R4 R = Peer reviewed scientific publications 4 = Verified data
Apis mellifera
Low
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
> 66.0
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes
Apis mellifera
Moderate
Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
-
-
-
Chronic
-
-
-
Notes
-
Bumblebees (Bombus spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
-
-
-
-
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
-
-
-
-
Mason bees (Osmia spp.)
Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
-
-
-
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
-
-
-
Other bee species (1)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
-
-
-
Mode of exposure
-
Other bee species (2)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
-
-
-
Mode of exposure
-
Beneficial insects (Ladybirds)
-
-
-
Beneficial insects (Lacewings)
-
-
-
Beneficial insects (Parasitic wasps)
-
-
-
Beneficial insects (Predatory mites)
-
-
-
Beneficial insects (Ground beetles)
-
-
-
Beneficial insects (Butterflies)
Contact
-
-
-
Notes
-
Oral
-
-
-
Notes
-
Aquatic ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
5.67
R4 R = Peer reviewed scientific publications 4 = Verified data
Oncorhynchus mykiss
Moderate
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
-
-
-
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
A0 A = Chromosome aberration (EFSA database) 0 = No data
;
B0 B = DNA damage/repair (EFSA database) 0 = No data
;
C0 C = Gene mutation (EFSA database) 0 = No data
;
D0 D = Genome mutation (EFSA database) 0 = No data
;
E0 E = Unspecified genotoxicity type (miscellaneous data source) 0 = No data
XNo, known not to cause a problem
Reproduction / development effects
Acetyl cholinesterase inhibitor
Neurotoxicant
No data found
XNo, known not to cause a problem
XNo, known not to cause a problem
Respiratory tract irritant
Skin irritant
Skin sensitiser
?Possibly, status not identified
✓Yes, known to cause a problem
✓Yes, known to cause a problem
Eye irritant
Phototoxicant
✓Yes, known to cause a problem
No data found
General human health issues
Tea tree oil is not a substance of serios toxicological concern when used as a pesticide but is an irritant
Handling issues
Property
Value and interpretation
General
Flammable Use foam, carbon dioxide or dry chemical for fire fighting Portect against electrostatic charges Not explosive or oxidising IMDG Transport Hazard Class 3
Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242
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Ecotoxicity
Human health
