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Chlorfenac
(Also known as: fenac; trifene)
SUMMARY
Chlorfenac is an obsolete herbicide for the control of annual weeds and grasses. It has a low aqueous solubility and ishighly volatile. It may be persistent in both soil and water systems. It is moderately toxic to aquatic fife but has a low toxicity to birds. It is moderately toxic to mammals if ingested.
Data alerts

The following 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.

Environmental fate Ecotoxicity Human health
Environmental fate
High alert:
GUS: High leachability
Warning:
Significant data are missing
Ecotoxicity
Moderate alert:
Fish acute ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate
Human health
Moderate alert:
Mammals acute toxicity: Moderate
Warning:
Significant data are missing
GENERAL INFORMATION
Description
An obsolete herbicide used to control annual weeds and grasses in sugarcane and non-cropped areas
Example pests controlled
Dandelion; Nightshade; Docks; Plaintains; Foxtail; Purslane; Thistles; Nettles; Crabgrass
Example applications
Sugarcane; Non-cropped areas such as rights-of-way, rangeland; Submerged aquatic weeds
Efficacy & activity
-
Availability status
Considered obsolete but may be available in some countries
Introduction & key dates
Early 1960s, developed
UK regulatory status
UK COPR regulatory status
Not approved
Date COPR inclusion expires
Not applicable
UK LERAP status
No UK approval for use
EC Regulation 1107/2009 (repealing 91/414)
EC Regulation 1107/2009 status
Not approved
Dossier rapporteur/co-rapporteur
Not applicable
Date EC 1107/2009 inclusion expires
Not applicable
EU Candidate for substitution (CfS)
Not applicable
Listed in EU database
No
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
-
Chemical structure
Isomerism
None
Chemical formula
C₈H₅Cl₃O₂
Canonical SMILES
C1=CC(=C(C(=C1Cl)CC(=O)O)Cl)Cl
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
QZXCCPZJCKEPSA-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C8H5Cl3O2/c9-5-1-2-6(10)8(11)4(5)3-7(12)13/h1-2H,3H2,(H,12,13)
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
chlorfenac -
General status
Pesticide type
Herbicide
Substance groups
Aromatic carboxylic acid compound; Unclassified pesticide
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Inhibits cell wall synthesis, Systemic, absorbed predominately by plant roots, with translocation. Auxin mimic.
CAS RN
85-34-7
EC number
201-599-3
CIPAC number
None allocated
US EPA chemical code
082601
PubChem CID
6805
CLP index number
607-074-00-9
Molecular mass
239.48
PIN (Preferred Identification Name)
(2,3,6-trichlorophenyl)acetic acid
IUPAC name
(2,3,6-trichlorophenyl)acetic acid
CAS name
2,3,6-trichlorobenzeneacetic acid
Other status information
Risk of drift
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Classification (HRAC)
O
Herbicide Resistance Classification (WSSA)
4
Insecticide Resistance Classification (IRAC)
Not applicable
Fungicide Resistance Classification (FRAC)
Not applicable
Examples of recorded resistance
-
Physical state
Colourless solid
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Amchem Products
  • Rhone-Poulenc Agrochemic
  • Hooker Chemical Company
  • Union Carbide
Example products using this active
  • Fenatrol
  • Trifene
  • Fenac
  • Tri-Fen
Formulation and application details
Usually supplied as granules or as an aqueous solution
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
6.14
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
 Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
- - -
Melting point (°C)
156
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 -
Boiling point (°C)
Decomposes before boiling
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
 -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
1.58 X 1003 Calculated -
Log P
3.2
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
 High
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.57
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
 -
Dissociation constant pKa) at 25 °C
3.7
DW4 DW = Don Wauchope personal database for Pka data: Wauchope, R. D. and Edwards, J. Dissociation constants for pesticide active ingredients: a database and comparison with predicted values. Dataset is no longer available.
4 = Verified data
 -
Weak acid
Vapour pressure at 20 °C (mPa)
1100
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 Highly volatile
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
- - -
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
-
Soil degradation (days) (aerobic)
DT₅₀ (typical)
180
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
 Persistent
DT₅₀ (lab at 20 °C)
- - -
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
USDA data
Dissipation rate RL₅₀ on plant matrix
Value
- - -
Note
-
Dissipation rate RL₅₀ 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
Stable
R4 R = Peer reviewed scientific publications
4 = Verified data
 Stable
Note
Stable at pH 5, 7 and 9
Water-sediment DT₅₀ (days)
- - -
Water phase only DT₅₀ (days)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
-
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
 Moderately mobile
Koc
400
Notes and range
-
Freundlich
Kf
- - -
Kfoc
-
1/n
-
Notes and range
-
pH sensitivity
-
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
3.15 Calculated High leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
4.12 X 10-01 Calculated -
Note
-
Potential for particle bound transport index
Medium Calculated -
Potential for loss via drain flow
Moderately mobile Calculated -
Bio-concentration factor
BCF (l kg⁻¹)
- - -
CT₅₀ (days)
- -
Known metabolites

None
ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 576
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat		 Moderate
Mammals - Short term dietary NOEL
(mg kg⁻¹)
- - -
(ppm diet)
- -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
> 5000
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Colinus virginianus		 Low
Birds - Short term dietary (LC₅₀/LD₅₀)
- - -
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)
- - -
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)
- - -
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
- - -
Soil micro-organisms
- - -
Collembola
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
Non-target plants
- - -
- - -
Honeybees (Apis 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)
- - -
Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
- - -
Chronic
- - -
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)
- - -
Aquatic ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
> 7.50
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Oncorhynchus mykiss		 Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
> 4.50
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Daphnia magna		 Moderate
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)
- - -
Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)
- - -
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)
- - -
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
- - -
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
19.16
P3 P = Other non-EU, UK or US Governments and Regulators
3 = Unverified data of known source
Chlamydomonas moewusii 7 day		 Low
Mesocosm study data
NOEAEC mg l⁻¹
- - -
NOEAEC mg l⁻¹
- - -
HUMAN HEALTH AND PROTECTION
General
Property
Value
Source; quality score; and other information
Interpretation
Threshold of Toxicological Concern (Cramer Class)
High (class III) - -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 576
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat		 Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
1440
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat		 -
Mammals - Inhalation LC₅₀ (mg l⁻¹)
- - -
Other Mammal toxicity endpoints
- - -
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
- - -
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
- - -
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)
- - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)
- - -
Dermal penetration studies (%)
- - -
Dangerous Substances Directive 76/464
- - -
Exposure Routes
Public
-
Occupational
-
MRLs
European
EU MRL pesticide database 
Great Britain
GB MRL Register 
Notes
-
Drinking Water Standards
- - -
Drinking Water MAC (μg l⁻¹)
- - -
Mammalian dose elimination route and rate
- - -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
No data found
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
 No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
No data found
XNo, known not to cause a problem
 No data found
Respiratory tract irritant Skin irritant Skin sensitiser
No data found No data found No data found
Eye irritant Phototoxicant  
No data found No data found  
General human health issues
Harmful if swallowed
May disturb body temperature regulation
May cause hypotension
Handling issues
Property
Value and interpretation
General
Not expected to autoignite; Not highly flammable
CLP classification 2013
Health: H302
Environment: H411
WHO Classification
III (Slightly hazardous)
UN Number
-
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
chlorfenac
French
chlorfenac
German
Chlorfenac
Danish
-
Italian
-
Spanish
clorfenac
Greek
-
Polish
chlorofenak
Swedish
-
Hungarian
-
Dutch
-
Norwegian
-
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